Epitaxial growth of composite scintillators based on Tb3Al5O12 : Ce single crystalline films and Gd3Al2.5Ga2.5O12 : Ce crystal substrates

Abstract

This work presents our latest achievements in the development of advanced composite scintillators for simultaneous registration of α-particles and γ-quanta in mixed ionizing fluxes based on single crystalline films (SCFs) of Tb₃Al₃O₁₂ : Ce (TbAG : Ce) garnet and Gd₃Al_2.5Ga_2.5O₁₂ : Ce (GAGG : Ce) single crystal (SC) substrates using the liquid phase epitaxy (LPE) growth method from a melt-solution based on a PbO–B₂O₃ flux. The separation of the signals from the SCF and SC components of such composite scintillators can be realized by means of registration of the difference in the scintillation decay times of SCF and substrate scintillators and can be achieved at a large K = t(SCF)/t(SC) ratio, which is usually above 2. The TbAG : Ce SCFs exhibit relatively fast scintillation response under α-particle excitation with decay times of t_1/e = 344–380 ns and t_1/100 = 3130–3770 ns. Meanwhile, the scintillation response of TbAG : Ce SCFs under α-particle excitation is significantly slower in the 500–4000 ns range than that of the GAGG : Ce crystals with decay times of t_1/e = 270–280 ns and t_1/20 = 1280–1300 ns. We have found that for TbAG : Ce/GAGG : Ce composite scintillators, the optimal K ratio changes from 2.0 to 3.0 at the registration of scintillations with shaping times of 700–4000 ns. For this reason, TbAG : Ce/GAGG : Ce composite scintillators possess the best scintillation properties among all known LPE grown analogues for simultaneous registration of α-particles and γ-quanta in mixed fluxes.