A combined spectrometric detector of fast neutrons

A combined spectrometric detector consisting of two subdetectors for fast and thermal neutrons has been developed. The fast neutron detector is a total absorption detector with a polystyrene-based scintillator generating a signal proportional to the absorbed energy of a fast neutron. The thermal neutron detector based on a 6 LiF/ZnS(Ag) scintillator in the form of a thin screen detects neutrons that have lost almost all their energy in the first detector and have been thermalized. The electronics of the combined detector operates in coincidence: if a neutron has been detector by the thermal neutron detector, the signal from the fast neutron detector participates in the formation of the amplitude spectrum within a predetermined time interval (fast neutron moderation time). The methods for reconstructing the neutron spectrum by the spectrum recorded using the combined detector are considered. The measured neutron spectra from various sources are presented.