Fabrication of Gd2O2S:Tb scintillation ceramics using water-bath method: The influence of initial reaction temperature

Gd2O2S:Tb nanopowders were synthesized in hot water-bath with the equal mole ratio of Gd2O3 and H2SO4 as raw materials. The influence of initial bathing temperature of Gd2O3 and H2SO4, which was defined as initial temperature, on the properties of precursors and powders was investigated. The precursors and Gd2O2S:Tb powders showed a layered structure, and all the reduced powders exhibit a pure Gd2O2S phase. With the increase of the initial temperature, the size and thickness of the flakes in the precursors and Gd2O2S:Tb powders increased. Using the obtained powders as starting materials, Gd2O2S:Tb scintillation ceramics were successfully fabricated by vacuum pre-sintering at 1250 degrees C for 3 h, followed by HIP post-treatment at 1450 degrees C for 3 h. The Gd2O2S:Tb ceramics from the powders prepared at lower initial temperature show a rapid densification rate during pre-sintering. The Gd2O2S:Tb ceramics from powders synthesized at 7 degrees C show the highest optical transmittance and XEL intensity, and the total transmittance of the ceramics with the thickness of 1.0 mm is 25.5% at 545 nm. The microstructures of the Gd2O2S:Tb ceramics from powders synthesized at different initial temperatures were also studied.