Abstract:
Gd
2O
2S:Tb scintillation ceramics exhibit a high neutron absorption cross-section, high light output, and excellent spectral matching performance. These ceramics eliminate optical losses associated with bubbles, powder particles, and binders commonly observed in traditional neutron powder scintillation screens. Gd
2O
2S:Tb ceramics enhance irradiation stability and extend service life, offering promising applications in neutron imaging. To obtain Gd
2O
2S:Tb powders with homogeneous composition, superior dispersion, and high sintering activity, precursors were synthesized from Gd
2O
3 powders, Tb(NO
3)
3, and H
2SO
4 via a hot water-bath reaction at 90 ℃. The precursors were transformed into Gd
2O
2SO
4 after air calcination at 600 ℃ for 3 h. Subsequent hydrogen reduction at 750 ℃ for 2.5 h yielded Gd
2O
2S:Tb powders with smaller lamellar particle size and more uniform dispersion. The morphology of the Gd
2O
2S:Tb powders was optimized by modulating the morphology of the initial Gd
2O
3 powders in combination with an analysis of the hot water-bath reaction mechanism. The influence of different Gd
2O
3 powders (commercial nano-, precipitation -synthesized, commercial micron-, and ball-milled commercial micron- Gd
2O
3 powders) on the morphology of Gd
2O
2S:Tb powders was investigated. Gd
2O
2S:Tb powders with smaller lamellar size, more uniform dispersion, and higher sintering activity were obtained using commercial nano-Gd
2O
3 powders. The Gd
2O
2S:Tb ceramics prepared from commercial nano-Gd
2O
3 powders via vacuum pre-sintering at
1300 ℃ for 3 h and hot isostatic pressing post-treatment at
1350 ℃ for 3 h under 176 MPa exhibited the highest total optical transmittance of 11.3%@545 nm (1 mm thickness) and the highest X-ray excited luminescence intensity. However, the presence of a secondary phase of Gd
2O
3 within the ceramics limits further improvement in the optical quality of Gd
2O
2S:Tb ceramics.