Fabrication of Gd2O2S:Tb scintillation ceramics from the uniformly doped nanopowder

Single-phase 2Gd2O3 center dot(Gd,Tb)2(SO4)3 center dot nH2O precursor with strong crystallinity was synthesized by the water-bath method through optimizing the introducing method of Tb3+ doping, where Tb3+ was introduced from Tb(NO3)3. The formation process and phase evolution of the precursor were analyzed in detail. Compared with the conventional method of introducing Tb3+ via Tb4O7, the inhomogeneous doping caused by the appearance of 2Tb2O3 center dot(Gd,Tb)2(SO4)3 center dot nH2O in the precursor was avoided. Pure Gd2O2S:Tb nanopowders with layered structure were obtained after calcination in flowing H2-Ar. The Gd2O2S:Tb powder prepared with Tb(NO3)3 has higher XEL intensity than that with Tb4O7. Using the synthesized powders as starting material, Gd2O2S:Tb scintillation ceramics with high relative density (over 99% of the theoretical value) were fabricated by vacuum pre-sintering and HIP post-treatment in an argon atmosphere. The influences of the introducing method of Tb3+ doping on the microstructure, photoluminescence and X-ray excited luminescence of the Gd2O2S:Tb ceramics were studied. The ceramic sample prepared with Tb(NO3)3 has better luminescence properties due to the homogeneous doping in the ceramics. Temperature-dependent XEL measurements imply that the green emission of the ceramic sample is always dominant with the increase of temperature from 77 K to 340 K, attributed to the cross-relaxation between 5D3 and 5D4 levels of Tb3+.

Automated summary

By optimizing the introducing method of Tb3+ doping, single-phase 2Gd2O3·(Gd,Tb)2(SO4)3·nH2O precursor with strong crystallinity was successfully synthesized. Pure Gd2O2S:Tb nanopowders with layered structure were obtained, and high relative density Gd2O2S:Tb scintillation ceramics were fabricated with vacuum pre-sintering and HIP post-treatment. The luminescence properties of the ceramics were improved with homogeneous doping, and temperature-dependent XEL measurements showed dominant green emission attributed to cross-relaxation between Tb3+ levels.