Abstract
The Precision Radiotherapy α-Isotope R&D Platform in Gansu Province aims to produce several alpha emitting isotopes. Due to the bombardment of Th-232 targets with 100 MeV protons, a high-energy n-γ mixed radiation field is generated. Here, we compared the calculated results for calculating the dose attenuation of neutrons in iron and concrete using FLUKA code and the analytical methods in standard DIN 6875-20. We analyzed the impact of carbon content on the shielding capabilities of iron, the results indicate that a small amount of carbon improves the shielding effect, and then compared the effects of different thicknesses of low-carbon steel and heavy concrete composite shielding on forward neutron dose attenuation. Additionally, we calculated and analyzed dose attenuation curves and energy spectra for 1 MeV and 20 MeV neutrons passing through heavy concrete, boron carbide, carbon steel, polyethylene, and borated polyethylene. The shielding capabilities of various materials and their combinations against the n-γ mixed field were compared, and then we optimized the lateral shielding compensation structures based on the results. Finally, we simulated the overall dose distribution of the target station. This study has its reference significance for engineering design of the target stations in the isotope production facilities.