Oxidation suppression of Cu in alkaline aluminophosphate glass and the effects for radiation-induced luminescence characteristics

A glass phosphor is an attractive material for applications in radiation detections because of its high workability and availability with a wide range of chemical compositions. Recently, X-ray-induced luminescence of glasses containing various luminescent activators are actively investigated worldwide. In applications as phosphor, tailoring valence state of activators, which can take multiple valence states in glass, is very important. In this research, we studied effects of glass melting atmosphere on the valence state of copper-activator ion in alkaline aluminophosphate glasses and the radiation-induced luminescence characteristics. Optical absorption and X-ray absorption near edge structure spectra of Cu-doped glasses showed that the glass fused in Ar atmosphere contains higher concentration of Cu(+) than those prepared in air. In addition, the presence of Cu(+) enhances the photoluminescence (PL) quantum yield and PL kinetic constant. Furthermore, the increase of Cu(+) concentration resulted an improvement of the X-ray-induced scintillation and thermally-stimulated luminescence intensity.