Enhanced Scintillation Efficiency and Reduced Afterglow in Gd2O2S:Pr Ceramics via La-Induced Structural Disorder and Liquid-Phase Synthesis

Abstract

Pr-doped gadolinium oxysulfide (Gd₂O₂S:Pr, GOS:Pr) ceramic scintillators are widely utilized in medical CT detectors and security screening systems. However, their lower scintillation efficiency compared to emerging gadolinium-based garnet scintillators, combined with the inefficiencies and contamination risks associated with traditional solid-state synthesis methods, limit the advantages of their continued application. To address these challenges, we developed a liquid-phase synthesis method for GOS:Pr powders incorporating Gd–La substitution. This approach enables the production of high-density ceramics through pressure-less sintering and hot isostatic pressing, thereby improving both processing efficiency and material integrity. The introduction of La³⁺ and the associated La–S bond formation result in increased structural disorder, leading to a 21% enhancement in scintillation efficiency and a 27% reduction in afterglow at 100 ms. These improvements are crucial for reducing patient radiation exposure and enhancing image quality in CT imaging, while maintaining the practical advantages of GOS:Pr scintillators.