Epitaxial growth of single crystalline film scintillators based on the Pr3+ doped solid solution of Lu3Al5−xGaxO12 garnet

Abstract

UV emitting scintillating screens based on single crystalline films (SCFs) of Lu₃Al_5−xGa_xO₁₂:Pr garnet have been developed by the liquid phase epitaxy (LPE) growth method onto Y₃Al₅O₁₂ (YAG) substrates using a lead-free BaO based flux. The absorbance, luminescence and scintillation properties of these SCFs have been investigated depending on the Ga content in the x = 0–1.9 range. We have found that the absorption and luminescence spectra of Pr³⁺ ions as well as the scintillation light yield (LY) and decay kinetics of Lu₃Al_5−xGa_xO₁₂ SCFs are non-linearly affected by the gallium concentration x in the mentioned solid solution due to preference for the distribution of Ga³⁺ and Al³⁺ ions between the tetrahedral and octahedral positions of the garnet host, respectively. The best scintillation properties of Lu₃Al_5−xGa_xO₁₂:Pr SCFs are achieved at the Ga content in the x = 1.0–1.2 range. The LY of the Lu₃Ga_1.2Al_3.8O₁₂:Pr SCF is comparable with the LY of the best reference LuAG:Pr single crystal counterpart and significantly (up to 3 times) overcomes the LY of LuAG:Pr and Lu₃Al_4–3.5Ga_1.0–1.5O₁₂ SCFs, grown onto the YAG substrates from the conventional PbO–B₂O₃ flux.