Li Co-Doped NaI:Tl (NaIL)—A Large Volume Neutron-Gamma Scintillator With Exceptional Pulse Shape Discrimination

We have demonstrated that Li can be substantially incorporated into the matrix of NaI under an optimized crystal growth process. The incorporation of Li introduces efficient neutron detection into an already successful commercial gammaray scintillator. Exceptional gamma-neutron pulse shape discrimination (PSD) has been demonstrated in Li co-doped NaI:Tl crystals with up to 8% Li concentration. Neutron-gamma PSD figure of merits are typically above 2 and can be high as 4.3 depending on the Li concentration. Gamma-ray performance of a single crystal Li co-doped NaI:Tl is on par with standard NaI:Tl. Simulations show that a Ø 50 mm × 50 mm
⁶
Li doped at 2% NaI:Tl detector has comparable neutron detection efficiency as a
⁶
Li-enriched Cs
₂
LiYCl
₆
:Ce of the same size. Hightemperature measurements have confirmed good gamma-neutron PSD to at least 160 °C. Creation of large volume (>1000 cm
³
), low cost, and dual-gamma spectroscopy/neutron sensitive detectors is possible with this technology.