This paper discusses the x-ray luminescence properties of Gd2O2S:Pr:Ce ceramic as a function of its chemical composition. It is established that heat treatment of the ceramic in air affects its x-ray luminescence parameters. A Gd2O2S:Pr:Ce ceramic has been fabricated that possesses weak phosphorescence—less than 20×10−6 of the initial luminescence intensity in 500 ms.
L. S. Bolyasnikova, V. A. Demidenko, S. B. Eron'ko, O. P. Ovsyannikova, and S. B. Mikhrin, "Gd2O2S:Pr:Ce optical scintillation ceramics and their properties," J. Opt. Technol. 73, 138-142 (2006)