Fast neutron spectra from a 14 MeV source in hybrid reactor system materials. 1.Pt

A single crystal fast neutron scintillation spectrometer is designed on the basis of the FEY-13 photoelectron multiplier with a stilbene crystal. A high discrimination level for the gamma-background is achieved. The neutron separation from the gamma-quanta is performed by the applied circuit comparing the charge associated with the fast part to the total charge of the scintillating pulse. The nonlinearity of FEY-13 is eliminated employing a higher discrimination threshold (3MeV) which makes possible the utilization of its favourable time characteristics in the spectrometric system. The relatively good energy resolution of the spectrometer allows its application in the form measurement of continuous fast neutron energy distributions in the 3 up to 14 MeV range for the hybrid reactor system materials as investigated by the authors