Pulse Shape Analysis of LiI:Tl Crystal Scintillators

The LiI:Tl crystal is a candidate for thermal neutron measurements and rare event searches due to the advantage of the lithium and iodide isotopes in its composition. This study shows the pulse shape discrimination (PSD) capability of thermal neutron irradiation. Particle discrimination is essential for improving neutron measurement and rare event searches to reduce unwanted backgrounds. To investigate the pulse-shape characteristics of LiI:Tl crystals with different radiations, digital analysis of pulse shape has been considered. The raw pulses were fitted with a suitable pulse form. The fitted pulses were studied in both the time and frequency domains which improve the Figure-of-Merit over the charge comparison methods. Our results show the change of PSD for LiI:Tl crystals with different Thallium concentrations. The surface effect is discussed, and other related scintillation characteristics were also studied.