Li⁺, Na⁺ and K⁺ co-doping effects on scintillation properties of Ce:Gd₃Ga₃Al₂O₁₂ single crystals

Ce0.5%: Ce:Gd₃Ga₃Al₂O₁₂(GGAG) single crystals co-doped with 500at.ppm Li⁺, Na⁺ and K⁺ were grown by using the micro-pulling down method. The smooth Ce⁴⁺ charge transfer absorption below 350 nm and decay time acceleration were observed in Li co-doped sample. Na⁺ and K⁺ co-doping did not show a large effect on the acceleration of decay time compared with Li co-doping. Ce0.5%:GGAG single crystals co-doped with 500 at.ppm Li⁺ were also grown by the Czochralski method. Optical, scintillation properties and timing performance were evaluated to investigate the effect of univalent alkali metal ions co-doping on Ce:GGAG scintillators. The scintillation decay curves were accelerated by Li co-doping: the decay time was significantly accelerated to 54.8 ns (47%) for the faster component and 158 ns (53%) for the slower component. The light output was 94% of the non co-doped Ce:GGAG standard. The coincidence time resolution was improved to 258 ps by Li co-doping.