Luminescence and scintillation properties of Cs2ZnCl4 and Cs3ZnCl5

Fast scintillation materials based on the ternary halide crystals of Cs2ZnCl4 and Cs3ZnCl5 were synthesized. Under X-ray irradiation, an emission band at 310 nm with shoulders at 260 and 410 nm was observed for Cs2ZnCl4, and emission bands at 240, 290, and 390 nm were observed for Cs3ZnCl5. The observed bands were primarily attributable to Auger-free luminescence (AFL). In the temporal scintillation profiles, scintillation decay time constants of 1.7 and 1.1 ns were found for Cs2ZnCl4 and Cs3ZnCl5, respectively. These fast components are attributed to AFL and constituted greater than 88% of the total scintillation amount. On the basis of the pulse height spectra, the light yields of Cs2ZnCl4 and Cs3ZnCl5 were estimated to be 1280 and 440 photons MeV−1, respectively. The light yield of the fast component of Cs2ZnCl4 was slightly lower than that of BaF2, which is a commercially available fast scintillator exhibiting AFL.