Choice of the Target Material for a Compact Neutron Source at a Proton Energy of 20-100 MeV

Be, Nb, Ta and W are considered as possible target materials for a compact neutron source. The thermal characteristics and the hydrogen-diffusion coefficients are taken into account. Using the simulation of particle transport in the PHITS program, estimates are obtained for the neutron yield when the target is irradiated with protons of various energies. Different optimal materials correspond to different energy ranges. The best results at energies up to 20 MeV are shown by Be, 20-35 MeV by Nb, and above 35 MeV by Ta. The latter two materials have an increased blistering resistance compared to beryllium but are behind it in terms of thermal conductivity. An increase in the energy of incident protons also leads to an increase in the number of neutrons generated per source proton due to a reduced time of the Coulomb interaction between the particle and the target-atom nucleus.