Photoluminescence, photoacoustic, and scintillation properties of Te4+ -doped Cs2HfCl6 crystals

Photoluminescence, photoacoustic, and scintillation properties are reported for 1.0, 3.0, 5.0, and 10 mol% Te4+ doped Cs2HfCl6 crystals grown using the vertical Bridgman-Stockbarger method. The UV - VIS light excited emission spectra showed an emission band peaking at 575 nm which can be ascribed to transitions from the T-3(1u) and (3)A(1u) states to the (1)A(1g) state of Te4+ ions. Excitation spectra monitored at emission wavelength of 575 nm showed bands at 230-250 (charge transfer on a HfCl62-), 275-300 ((1)A(1g) -> T-3(1u)), 300-340 ((1)A(1g) -> T-3(2u), E-3(u)), and 360-460 nm ((1)A(1g) -> T-1(1u)). The X-ray induced scintillation spectra exhibited a yellow emission band at 575 nm, which is similar to the emission band for excitation by UV-VIS light. Scintillation light yields of the crystals were estimated to be approximately 11,700 (1.0 mol%), 13,100 (3.0 mol%), 9600 (5.0 mol%), and 9000 (10 mol%) photons/MeV, respectively. Scintillation light yield was inversely correlated with the PA intensity.