Luminescence and scintillation properties of Lu3Al5O12 nanoceramics sintered by SPS method

• Ce-doped scintillation nanoceramics were prepared by a Spark-Plasma-Sintering method.
• High overall scintillation efficiency was found.
• For samples prepared with slower pre-heating, scintillation efficiency can be increased by annealing.
• Higher sintering temperatures and slower pre-heating stages positively influence scintillation efficiency.

Ce-doped lutetium aluminum garnet Lu3Al5O12 (LuAG) nanoceramics were fabricated at 1600 °C and 1700 °C by spark-plasma sintering (SPS) method from nano-powders prepared by radiation synthesis. Both undoped and Ce-doped LuAG ceramic samples were also prepared from the nano-powders at 1700 °C with significantly increased pre-heating rate. The backscattered electron images revealed large amount of pores in all the Ce-doped samples causing their significant opacity. On the other hand, very large grains and no pores were revealed in the undoped sample, which was the only transparent one. The radioluminescence measurements revealed superior overall scintillation efficiency of the samples sintered at the temperature 1700 °C, and their defect emission in the UV region was ascribed to oxygen-vacancy-related defects such as F+ centers. The photoluminescence decay of the defect emission was characterized by an extremely fast decay time of a few nanoseconds. Influence of sintering procedure and subsequent annealing on the luminescence and scintillation properties is discussed.