MCNP simulation for gamma-ray buildup factors of shielding material

Abstract

BackgroundIn the shielding design of γ-ray, it is very important to select the appropriate buildup factor for the shielding effect. As far as the current data are concerned, when designing the shielding material, the effect of bremsstrahlung is considered for the single-layer materials, but not for composite materials.PurposeThis study aims to improve the accuracy of the shielding thickness calculation with the consideration of γ-ray buildup factors by simulation.MethodsThe Monte Carlo method was used to simulate the buildup factors in different γ-ray energies and different shielding material thickness. Buildup factors of single-layer materials and multilayer composite materials were calculated with the consideration of bremsstrahlung and compared with those without bremsstrahlung.ResultsSimulation results show that the contribution of bremsstrahlung to the buildup factor is lower at low energies and thin shielding thicknesses for single-layer materials and composite materials, but it is more obvious at high energies and high shielding thicknesses. The buildup factors show a decreasing trend with the increase of γ-ray energy, and show an increasing trend with the increase of shielding thickness.ConclusionsThis study provides a reference and calculation method for the buildup factor for shielding design of high-energy γ-ray in actual situations.

Keywords

• buildup factor
• shielding material
• mcnp simulation
• bremsstrahlung