Optical and scintillation properties of LuGd_2Al_2Ga_3O_(12):Ce, Lu_2GdAl_2Ga_3O_(12):Ce, and Lu_2YAl_2Ga_3O_(12):Ce single crystals: A comparative study

摘要

Optical and scintillation properties of LuGd_2Al_2Ga_3O_(12):Ce, Lu_2GdAl_2Ga_3O_(12):Ce, and Lu_2YAl_2Ga_3O_(12):Ce single crystals are compared. The blue-shift of 5d_1→4f photoluminescence emission (PL) band is observed upon partial substitution of Gd~(3+) with a smaller Lu~(3+) (or Y~(3+)) ion. At 662 keV γ-ays, the light yield of 35,400 ± 1,700 ph/MeV obtained for LuGd_2Al_2Ga_3O_(12):Ce is higher than that of 29,200 ± 1,500 ph/MeV and 20,200 ± 1,000 ph/MeV for Lu_2GdAl_2Ga_3O_(12):Ce and Lu_2YAl_2Ga_3O_(12):Ce, respectively. Scintillation decays are approximated by sum of exponentials with the fast component decay time and relative intensity of 78 ns (42%) for LuGd_2Al_2Ga_3O_(12):Ce, 48 ns (71%) for Lu_2GdAl_2Ga_3O_(12):Ce and 45 ns (88%) for Lu_2YAl_2Ga_3O_(12):Ce, which leads to a superior coincidence time resolution of Lu_2YAl_2Ga_3O_(12):Ce. PL decay time at 110 K and 290 K, afterglow characteristics, and mass attenuation coefficient at 59.5 keV and 662 keV γ - rays are also presented.