Characterizations of a New Tl-based Elpasolite Scintillator: Tl2LiScCl6

A new Tl2LiScCl6 (TLSC) single crystal was grown by using the two-zone vertical Bridgman method. The TLSC belongs to the cubic chloro-elpasolite crystal family. Under X-ray excitation at room temperature, an emission spectrum from 300 to 550 nm was obtained, with the maximum emission being at 385 nm. The scintillation properties, such as the energy resolution, light yield and decay time of the TLSC crystal, were measured at room temperature by using a Cs-137 gamma-ray source. The energy resolution at the 662 keV photopeak was found to be 8.3% (full width at half maximum). Using the LYSO light yield as a reference, we obtained the light yield of the TLSC crystal as 26000 +/- 2600 ph/MeV under excitation by 662 keV gamma-rays. The developed crystal shows a single exponential decay time of 1.147 mu s under 662 keV gamma-ray excitation from a Cs-137 source. Due to the high effective Z-number (67) and density of the TLSC crystal, it can be used for efficient detection of X- and gamma-rays in various applications. It also has a potential to be used for detection of thermal neutrons via the Li-6(n, alpha) reaction. Further improvements in the scintillation properties are expected with rare-earth doping in this compound, which is the subject of our future work.