Radiation discrimination in LiBaF3 scintillator using digital signal processing techniques

Pulse analysis techniques with the scintillator LiBaF₃:Ce allow very clean separation of densely ionizing radiation (protons, deuterons, tritons, alphas, etc.) from less densely ionizing radiation (electrons). Consequently, pulse height spectra for each type of radiation can be obtained simultaneously. The pulse discrimination is based on the presence or absence of sub-nanosecond core-valence luminescence and in crystals doped with Ce⁺³ the presence or absence of Ce luminescence having a ^-35 ns lifetime. We are developing a pulse discrimination technique based on digital signal processing (DSP) using a CAMAC based module from XIA, Inc. Discrimination between electrons (gammas) and the light charged particles is based on the ratio of signal amplitude in the first 50 ns to signal amplitude at a longer time interval. We are evaluating more complicated algorithms to determine whether discrimination between hydrogen isotopes and alpha particles can be achieved. These techniques may allow determination of pulse height spectra for thermal neutron capture events, fast neutron capture events, fast-neutron-induced nuclear reactions, alpha events from Ra impurities in the scintillator, and gamma events simultaneously using a single scintillator.