Highly efficient Na_5Gd_9F_32:Tb^3+ glass ceramic as nanocomposite scintillator for X-ray imaging

Mono-crystal scintillator materials suffer from issues of complex, time-consuming techniques as well as small volume. Here, bulk Tb3+-doped Na5Gd9F32 glass ceramic (GC) scintillators with relatively high transparency were successfully manufactured via the melt-quenching method with further thermal treatment. Their structural and luminescent properties were systemically investigated by a series of characterization techniques including XRD, TEM, absorption spectra, photoluminescence (PL) excitation and emission spectra, lifetime measurements, and X-ray excited luminescence (XEL). Luminescent spectroscopy results show that the optimum doping concentrations of Tb3+ in precursor glass (PG) and GC systems are both 4 mol%. The XEL intensity of PG is about 64% of that of a commercial Bi4Ge3O14 (BGO) scintillator with the same thickness. Benefiting from the incorporation of Tb3+ ions into Na5Gd9F32 nanocrystals, enhanced PL and XEL of Tb3+ ion are realized after crystallization. The internal PL quantum yield of GC is 43.0% and the XEL intensity of GC reaches 130% of that of a BGO scintillator. Our results demonstrate that Na5Gd9F32 GC may act as an efficient scintillator with large-volume and low-cost.