Heavy Concrete Attenuation Study as Radiation Shield in Proton Therapy Using Monte Carlo Simulation

This research was conducted to attenuation of various types of concrete as shielding materials against neutron and photon radiation emitted from a proton source with an energy range of 100 MeV - 230 MeV. The MCNP 6.2 code is used to analyze the interaction of radiation with shielding materials, specifically on linear energy deposition (MeV/g) from various shield thicknesses and the linear attenuation coefficient (μ) as well as the mass attenuation coefficient (μ/ρ) from different energy ranges. The materials analyzed include concrete with heavy aggregates such as hematite and galena, compared to Low Activation Concrete (LAC). The research results show that the values of μ and μ/ρ decrease as the energy used increases. In a high-energy proton source, the values of μ and μ/ρ tend to be smaller because protons have high momentum and can penetrate materials more efficiently. Heavy galena concrete has a higher linear attenuation coefficient value of 0.073116 cm^-1 compared to heavy hematite concrete 0.049318 cm^-1 and LAC 0.056358 cm^-1. The selection of shielding material must consider not only the thickness of the shield but also the density and composition of the material's elements that affect its high radiation absorption capacity. From the research, this type of concrete can be used as a reference for making effective heavy concrete shields in proton therapy.