Spatial distribution of reflected gamma rays by Monte Carlo simulation

In nuclear facilities, the reflection of gamma rays of the walls and metals constitutes an unknown origin of radiation. These reflected gamma rays must be estimated and determined. This study concerns reflected gamma rays on metal slabs. We evaluated the spatial distribution of the reflected gamma rays spectra by using the Monte Carlo method. An appropriate estimator for the double differential albedo is used to determine the energy spectra and the angular distribution of reflected gamma rays by slabs of iron and aluminium. We took into the account the principal interactions of gamma rays with matter: photoelectric, coherent scattering (Rayleigh), incoherent scattering (Compton) and pair creation. The Klein-Nishina differential cross section was used to select direction and energy of scattered photons after each Compton scattering. The obtained spectra show peaks at 0.511^∗ MeV for higher source energy. The Results are in good agreement with those obtained by the TRIPOLI code J.C. Nimal et al., TRIPOLI02: Programme de Monte Carlo Polycin?etique à Trois dimensions, CEA Rapport, Commissariat à l’Energie Atomique. 1]].