Fast neutron and alpha detection using LiBaF3 scintillator

Pulse-shape discrimination techniques using the scintillator LiBaF3 allow v ery clean separation of densely ionizing radiation (protons, tritons, alpha s, etc.) from less densely ionizing radiation (electrons). The pulse-shape discrimination is based on the presence or absence of subnanosecond core-va lence luminescence and in crystals doped with Ce+3 the presence or absence of Ce luminescence. We use a pulse discrimination technique based on integr ation of the signal over a short time interval compared to integration over a long time interval. Thermal neutron capture events, fast neutron capture events, fast neutron elastic scattering events on Li, and alpha events fro m Ra impurities in the scintillator have distinctive loci in a two-dimensio nal plot of the short-gate pulse heights versus long-gate pulse heights. Th e resolution (full-width at half-maximum) of the (CS)-C-137 gamma photopeak is about 16%, and the resolution of the thermal neutron peak from neutron capture on Li-6 is about 17%. Applications of this scintillator include mea surements of fast to thermal neutron ratios, fast neutron spectroscopy, alp ha contamination, etc., in the presence of significant gamma radiation.