KTb3−xGdxF10 Nano-Glass Composite Scintillator with Excellent Thermal Stability and Record X-Ray Imaging Resolution

Scintillators exhibiting both excellent spatial resolution and thermal stability are highly sought after. Herein, by employing a suite of techniques—including phase-separation-assisted crystallization, energy transfer, and compensation—Tb 3+ -doped nano-glass composite (nano-GC) scintillators are developed with good scintillation performance. The Tb 3+ -doped nano-GC scintillator exhibits an unprecedented enhancement in the integrated intensity of X-ray excited luminescence (XEL) by more than five times, as compared with Bi 4 Ge 3 O 12 (BGO) crystal. It achieves an estimated light yield of 54 900 photons MeV −1 and a sensitivity of 635.31 nGy air s −1 . An X-ray imaging system based on the Tb 3+ -doped nano-GC scintillator delivers a record resolution of 28.7 lp mm −1 at room temperature and 28.1 lp mm −1 even at 500 °C, thanks to the excellent thermal stability, namely, the scintillator preserves the original XEL intensity up to 300 °C, and ≈73% at 500 °C. The heat resistance excels currently available high-temperature scintillation materials. These attributes, combined with robust moisture resistance, position the developed nano-GC scintillator an exceptionally promising candidate for high-temperature X-ray imaging used in harsh environments.