Shielding design of NanoTerasu for gas bremsstrahlung and photonuclear reaction

To exclude an experimental hall from a radiation-controlled area at the state-of-the-art 3 GeV synchrotron radiation facility, NanoTerasu, Japan, the shielding design of optical hatches for gas bremsstrahlung from a storage ring and secondary radiations induced by photonuclear reactions was precisely undertaken using the particle-transport Monte Carlo code, PHITS. The energy spectrum of gas bremsstrahlung expected for the NanoTerasu storage ring was calculated using analytical formulas and PHITS with EGS5 algorithm. The effective dose rates behind the optical elements and hatches estimated using PHITS and analytical formulas were consistent with accuracy factors of 1-2.