Tl2NaScCl6: A New Tl-based Elpasolite Crystalline Scintillator

Abstract

A scintillator for X-ray and gamma-ray detection must possess high light yield, good energy resolution, and high effective atomic number. In this study, we fabricated Tl2NaScCl6 crystals using the vertical Bridgman method and investigated their luminescence, scintillation properties, and scintillation mechanisms. The photoluminescence and X-ray-induced radioluminescence (XRL) spectra reveal broad emission bands peaking at 410 and 430 nm, respectively. The temperature dependence of the intensity of XRL spectra follows the Arrhenius equation, indicating that the luminescence of the Tl2NaScCl6 crystals is a self-trapped exciton emission or exciton-related emission. The light yield and energy resolution calculated from the 137Cs-gamma-ray pulse-height spectra are 20000 photons/MeV and 5.3%, respectively. These results suggest that Tl2NaScCl6 crystals are promising scintillators for X- and gamma-ray detection.