Luminescence and vacuum ultraviolet excitation spectroscopy of cerium doped Gd3Ga3Al2O12 single crystalline scintillators under synchrotron radiation excitations

Cerium doped Gd₃Ga₃Al₂O₁₂ (GGAG) single crystals as well as GGAG:Ce single crystals co-doped by divalent (Mg²⁺, Ca²⁺), trivalent (Sc³⁺) or tetravalent (Zr⁴⁺, Ti⁴⁺) ions have been studied by means of the excitation luminescence spectroscopy in vacuum ultraviolet spectral range. Synchrotron radiation from the undulator beam was utilized for the luminescence excitation in the energy range from 4.5 to 800 eV. The influence of the co-dopant ions on the excitonic transitions as well as on the intrinsic defects in GGAG was revealed examining the luminescence emission and excitation spectra of both Gd³⁺ and Ce³⁺ ions in all single crystals studied. Special attention was paid to the analysis of Ce³⁺ excitation spectra in VUV spectral range (4.5–45 eV) where multiplication of electronic excitation (MEE) processes occur. It was obtained that GGAG:Ce single crystals having different co-dopant ions reveal distinguished efficiency of MEE. The role of intrinsic defects in MEE processes in the co-doped GGAG:Ce single crystals was elucidated.