We evaluated the accelerator beam power and the neutron-induced radioactivity of 9Be(p, n) boron neutron capture therapy (BNCT) neutron sources having a MgF2, CaF2, or AlF3 moderator and driven by protons with energy from 8MeV to 30MeV. The optimal moderator materials were found to be MgF2 for proton energies less than 10MeV because of lower required accelerator beam power and CaF2 for higher proton energies because of lower photon dose rate at the treatment position after neutron irradiation. •We examined moderators depending on proton energy about accelerator-based sources.•We evaluated γ-dose rate due to neutron-induced radioactivity about the sources.•MgF2 was best for energy less than 10MeV due to a lower accelerator beam power.•CaF2 was best for energy more than 10MeV due to a lower dose at a patient place.