Fabrication of Gd2O2S:Pr scintillation ceramics from water-bath synthesized nanopowders

Crystallized precursor (Pr,Gd)(2) (OH)(4)SO4 center dot nH(2)O with stacked layered structure was prepared through a simple water-bath method with rare earth oxide powders and concentrated sulfuric acid as the only starting materials. Phase transformations of the precursor in air or reducing atmosphere together with various calcining temperature were investigated. Pure Gd2O2 S:Pr nanopowder that obtained by reducing the precursor under flowing hydrogen atmosphere remained same layered structure as the precursor. The Gd2O2 S:Pr scintillation ceramics with the relative density over 99% of theoretical value were prepared through pre-sintering in vacuum followed by HIP post-treatment in argon atmosphere. Under X-ray excitation, bright green emission centered at 511 nm could be observed in both Gd2O2 S:Pr powders and ceramics due to the P-3(0)-H-3(4) transition of Pr3+. CIE chromaticity coordinates of (0.232, 0.610) and (0.253, 0.596) correspond to the PL and XEL luminescence of the ceramics, respectively. The photoluminescent lifetime of Pr3+ P-3(0)-H-3(4) transition was measured to be 6.73 us under 337 nm excitation. Method for preparing GOS powder and ceramics in this work is relatively simple and environmentally friendly and is expected to be applied in the preparation of rare earth ions doped GOS materials.