Novel Phenomenon of Scintillation Performances with the Component Variation in the Mg Co-/Nondoped GAGG:Ce Crystal

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Gd 3 Al 2 Ga 3 O 12:Ce (GAGG:Ce) shows potential application in the next-generation positron emission tomography material due to its high light yield and excellent energy resolution. The main method currently available to accelerate the scintillation decay time of GAGG:Ce is mainly through the codoping of low valence ions such as Mg 2+, which partially converts Ce 3+ to Ce 4+ through a charge compensation mechanism. However, there is no clear and reasonable explanation for the deterioration of light yield by codoping with Mg 2+ in GAGG:Ce. Therefore, further study of the Mg 2+ codoping GAGG:Ce crystal is of great importance for improving the scintillation properties of GAGG:Ce. In this study, two sets of GAGG crystal samples containing different Ce concentrations without or with 0.5 atom % of Mg 2+ ion codoping were grown by the micropulling down method. The optimal Ce concentration decreases after Mg 2+ codoping, whereas the light yield degenerates significantly. This novel phenomenon suggests that the reduction of light yield after Mg 2+ codoping is not only due to the reduction of the luminescence center but also the formation of {Ce 3+ –Mg 2+ } and {Ce 4+ –Mg 2+ } associates affects the luminescence emission. This work can provide a novel and significant view for high-performance codoped GAGG:Ce component design and performance modification.