Detection of fast neutrons with NaI(Tl) crystal

An attempt has been made of using NaI(Tl) crystal as fast neutron detector in conventional Time-of-flight apparatus. Typical pulse hight distributions, in the γ-ray energy range below 1 MeV, produced by the incidence of fast neutrons are presented. The characteristics of this neutron detection system have been studied, using pulsed neutrons from the T(p, n) and D(d, n) reactions. Neutron detection efficiency curves are presented, covering both whole γ-rays and those from a few low excited levels of ¹²⁷I nucleus. The detection bias can be stably set at the first excitation energy (58 keV), which is lower than possible for an organic scintillator. (author)