On the slowing-down of 14 MeV fusion neutrons: A spectrometry benchmark and perspectives on future neutron science facilities

Abstract

The spectral fluence rate of the thermalized neutron field obtained by slowing down the 14 MeV fusion neutrons produced at the accelerator-driven Frascati Neutron Generator is measured by means of the Bonner Sphere Spectrometer. Neutron thermalization is achieved by means of a moderator assembly made of a copper pre-moderator and a polyethylene moderator. A Monte Carlo simulation reproducing the experimental set-up is also performed by means of the MCNP code and the results are compared to the experimental data. The benchmarked Monte Carlo is then used to predict the brilliance of a thermal moderator operating at a potential highintensity 14 MeV neutron continuous source featuring a neutron emission rate of 10 15 s −1 . The results obtained show that if a D-T neutron source featuring a continuous neutron emission rate of 10 15 s −1 could be made operative, it could be effectively exploited for neutron science.