New types of composite scintillators based on the single crystalline films and crystals of Gd3(Al,Ga)5O12:Ce mixed garnets

Abstract This work presents the results of creation of novel composite scintillators based on the Gd3Al5-x GaxO12:Ce (x = 1.16–2.67) single crystalline films (SCF), grown by the LPE method onto Gd3Al2.5 Ga2.5O12:Ce single crystal (SC) substrates. The scintillation properties of film/crystal epitaxial structures were investigated under α–particle and γ–quantum excitations. Under α–particle excitation, the light yield of mentioned SCF scintillators is significantly less than that in their substrates due to the influence of Pb2+ flux contamination and formation of Pb2+-Ce4+ centers. Meanwhile, these SCF scintillators under α–excitation possess significantly faster decay kinetics than that of their substrates under γ–excitation. Therefore, the Gd3Al5-xGaxO12:Ce SCFs (x = 1.16–2.67) /Gd3Al2.5Ga2.5O12:Ce SC epitaxial structures can be used as composite scintillators for simultaneous registration of the components of mixed ionizing fluxes, specifically for detection of α–particles (SCF) and γ–quanta (substrate). The separation of the response from the SCF and substrate parts of composite scintillators under α–particle (241Am) and γ–quantum (137Cs) excitations occurs at large tγ/tα = 1.7–4.2 ratio.