Liquid phase epitaxy growth of high-performance composite scintillators based on single crystalline films and crystals of LuAG

Abstract

This work is devoted to the development of two novel types of advanced composite scintillators based on single crystalline films (SCFs) of Lu₃Al₅O₁₂ garnet (LuAG), doped with Ce³⁺ and Pr³⁺ ions, and substrates from single crystals (SCs) of Sc³⁺ doped LuAG using the liquid phase epitaxy (LPE) method. We show the possibility for simultaneous registration of α-particles and γ-quanta using separation of the decay kinetics of the SCF and crystal parts of such composite scintillators. Namely, large differences in the respective scintillation decay kinetics and decay time values t_α and t_γ are observed for LuAG:Ce SCF/LuAG:Sc SC and LuAG:Pr SCF/LuAG:Sc SC composite scintillators under excitation by α-particles from an ²⁴¹Am (5.5 MeV) source and γ-quanta from a ¹³⁷Cs (662 keV) source. Thus, both developed types of composite scintillators can be applied for simultaneous registration of α-particles and γ-quanta in mixed radiation fluxes. The rate of discrimination of the scintillation signals, coming from the SCF and SC parts of the LuAG:Ce SCF/LuAG:Sc SC composite scintillator, expressed by the t_γ/t_α ratio, is equal to 1.34–1.96 in the 0–1100 ns time interval. For the LuAG:Pr SCF/LuAG:Sc SC composite scintillators, more significant differences in the scintillation decay kinetics are achieved. In this case, the t_γ/t_α ratio for these composite scintillators reaches the values 9.6–15.6 in the wide 0–2500 ns time interval. This is the best result among all the types of composite scintillators we developed based on epitaxial structures of garnet compounds.