Measurement of the energy of fast neutrons in the presence of gamma rays using a NaI(Tl) and a plastic scintillator

In many radiological laboratories, the energies of fast neutrons are very important for radiation diagnostics. In this paper we propose a method based on NaI and plastic scintillation (PS) detectors that measures the fast neutrons. The PS detector is sensitive to both gamma rays and fast neutrons. The NaI(Tl) detector is only sensitive to gamma rays. By subtracting the gamma information from the neutron–gamma mixed energy spectrum, pure neutron radiation information is obtained. Then, applying an unfolding method, the energy distribution of the fast neutron is generated. To verify this method, an experiment measuring the energy of monoenergetic neutrons was performed with the result confirming the effectiveness of this method.