Evaluation of Skyshine Dose for the Proton Accelerator Facility of the Proton Engineering Frontier Project in Korea

Evaluation of the skyshine dose for the proton linac facility of the Proton Engineering Frontier Project in Korea was performed in this study. To predict the skyshine dose level outside of the facility, a Monte Carlo method (MCNPX code), analytical method using an estimation formula, and SKYSHINE-KSU codes using an integral line-beam method were considered in the evaluations. The neutron spectrum at the outer surface of the roof of the facility was considered as the radiation source term. The results from each method were in good agreement for the distance from 200 to 1000 m. The neutron dose of 1.65 × 10^-4 Sv/h is expected at the fence of the facility, which is 400 m from the accelerator room.