Effect of nanostructuring of coprecipitated precursors on the morphology and scintillation properties of multication ceramics with a garnet structure

Single-phase polycrystalline samples of the (Gd,Y)$_3$Al$_2$Ga$_3$O$_{12}$:Ce,Tb composition with a garnet structural type were obtained. Using various approaches to the preparation of the initial powders of hydroxycarbonate precursors and compaction methods, the grain size of the ceramics was varied. The scanning electron microscopy method was used to establish the features of the microstructure of the initial powders with different processing temperatures and the microstructure of the resulting ceramics. It is shown that an increase in the grain size of the ceramics and a decrease in the residual porosity gives a noticeable increase in optical transparency in the visible region of the spectrum, in which Ce$^{3+}$ and Tb$^{3+}$ ions emit during scintillation. The effect of intergrain boundaries of the ceramics on the diffusion features of nonequilibrium carriers, electrons and holes, as well as excitons formed during the absorption of ionizing radiation on the scintillation yield and energy resolution is considered.