Investigation of Dose Rate Distribution in an Experimental Hall of a RIKEN Accelerator-Driven Compact Neutron Source Based on the ⁹Be(p, n) Reaction With 7 MeV Proton Injection

To characterize the dose rate distribution in an experimental hall of a RIKEN accelerator-driven compact neutron source (RANS) based on 9Be(p, n) reaction with 7 MeV proton injection, systematical measurements and calculations for gamma-ray rates by GEometry ANd Tracking (GEANT), Particle Heavy Ion Transport code System (PHITS), Monte Carlo N-Particle (MCNP) codes were performed. Calculations always underestimated when beam loss effect was not considered. Relatively good agreements observed among different simulation codes. explain underestimations, additional dominant sources due to identified at position around exit drift tube linac (DTL), made copper, pipe from quadrupole (Q) magnets steering (ST) magnets, aluminum, placing collimators along linac. The fractions 2%–3% copper 1% respectively, most appropriate estimation. In addition, we proposed possible measures reduce measured total $3.8~\mu $ Sv/h operator control room, addition wall entrance extension borated polyethylene (BPE) end beam. As result, became 2.5 times lower than current one.