The Stable Ce4+ Center: A New Tool to Optimize Ce-Doped Oxide Scintillators

Abstract

The role and effect of stable Ce4+ centers in Ce-doped LuAG single crystal scintillator is further studied by means of measurements of several optical, luminescence and scintillation characteristics. Two LuAG:Ce single crystal samples are compared: in one of them the dominating Ce4+ center is stabilized by high concentration Mg2+ codoping while the other one shows only the presence of stable Ce3+ center. Tailored (Eu, Mg)-doped LuAG single crystal is also prepared to test the presence and thermal stability of hole traps in the host which affect the timing characteristics of Ce4+ scintillation cycle, namely its restoration back to 4+ charge state in last step of the cycle. EPR experiment was also employed at Mg- and (Eu, Mg) doped LuAG samples and the signature of the O- hole center stabilized by Mg2+ ion was clearly obtained.