Monte Carlo simulation-based design for an electron-linear-accelerator-driven subcritical neutron multiplier for boron neutron capture therapy

Fuel configurations for a subcritical neutron multiplier, which was embedded in a beam-shaping assembly and irradiated by electrons from a linear accelerator, were examined to maximize the production of the epithermal neutron flux for boron neutron capture therapy. The epithermal neutron flux at the treatment position increased as the area per uranium fuel plate increased and was estimated to be 2 × 109 cm−2 s−1 when the subcritical neutron multiplier was irradiated by a 4.4 kW (0.22 mA) beam of 20 MeV electrons.