Neutron spectrometry with a recoil radiator-silicon detector device

A neutron spectrometer consisting of a commercial p–i–n diode coupled with a polyethylene converter was developed and tested. The spectra of the energy deposited by recoil-protons in the silicon detector were measured with mono-energetic neutron beams. The spectra of deposited energy were also calculated analytically and with Monte Carlo simulations using the FLUKA code. The effect of secondary charged particles produced by thermal and fast neutron interactions in the silicon diode was also investigated. Further measurements were made for neutrons generated by 5 MeV protons striking a thick beryllium target. The derived neutron spectrum was compared with spectra from the literature. Satisfactory agreement was found. The use of the spectrometer is limited by the effect of photons.