Preparation of Ce-Doped Gd3(Al, Ga)5O12 Nanopowders via Microwave-Assisted Homogenization Precipitation for Transparent Ceramic Scintillators.

ABSTRACT

Ce-doped gadolinium gallium aluminum oxide (Ce GGAG) precursors were first prepared by the microwave-assisted homogeneous precipitation method (MAHP). Thermal gravity-differential thermal analysis (TG-DTA), X-ray diffraction (XRD), specific surface area analysis (BET) and field emission scanning electron microscopy (FE-SEM) were employed to investigate the crystal structure, phase evolution and morphologies of the Ce GGAG precursors and powders. The influence of Ga ion concentration in the salt solution on the properties of Ce GGAG powders was investigated. All the precursors were transformed into single-phase GGAG after being calcined at 950 °C in a furnace for 3 h. Monodispersed Ce GGAG powders were obtained as the Ga ion concentration was lower than 0.06 mol/L. Single-phase and dense Ce GGAG ceramics were obtained after sintering at 1600 °C in a flowing oxygen atmosphere for 10 h. Specifically, the Ce GGAG ceramic reached its maximum density of ~6.68 g/cm3, which was close to its theoretical density of 6.70 g/cm3, and exhibited the highest optical transmittance of 65.2% at 800 nm after hot isostatic pressing sintering (HIP) as the Ga ion concentration was 0.02 mol/L. The decay time and light yield of the GGAG ceramic were 35 ns and 35,000 ± 1250 ph/MeV, respectively, suggesting that Ce GGAG ceramics prepared using MAHP-synthesized nanopowders are promising for scintillation applications.