Effect of Li+ ions co-doping on luminescence, scintillation properties and defects characteristics of LuAG:Ce ceramics

Monovalent Li+ codoped Lu3Al5O12:Ce (LuAG:Ce) optical ceramics were fabricated by solid state reaction method and further optimized by an air-annealing process. Optical absorption, radioluminescence spectra and scintillation properties such as light yield, scintillation decay times and afterglow were measured and compared with those of the Li+ free LuAG:Ce ceramic and the commercial LuAG:Ce single crystal samples. Positive effect of Li+ codopant consists mainly in the significant increase of scintillation light yield, acceleration of scintillation decay as well as the decrease of afterglow intensity. With 0.3% Li codoping, the obtained LuAG:Ce,Li ceramic displays a light yield of ∼29200 ph/MeV at 10 μs shaping time, higher than that of the LuAG:Ce single crystal and optical ceramic scintillators ever reported. The partial conversion of the stable Ce3+ to Ce4+ centers and the shallow and deep traps effect suppression by the Li+ codoping are discussed.