A simulation study on beam property of 124Sb–Be isotope-based neutron for BNCT

Abstract The 9Be(γ,n) neutrons with the energies at 21–24 keV generated by 1.691 MeV photons from 124Sb was investigated as a source of epithermal neutrons for BNCT, using PHITS code. A beam shaping assembly composed of 13 mm thick Be target, a gamma ray shield made of 30 cm thick Bi, and a reflector of 30 cm thick Pb satisfied the beam requirements of IAEA-TECDOC-1223. The needed 124Sb activity was estimated in the order of 1016–1017 Bq. Feasibility of BNCT using 124Sb–Be neutrons would be influenced by the capability of periodic supply of short-lived 124Sb (half-life: 60 days) with such high activity.