Thermally stimulated luminescence in X-ray irradiated oxide glasses doped with Ce(III)
Tanaka Katsuhisa; Hirao Kazuyuki; Tanaka Hideaki; Soga Naohiro
Abstract:Thermally stimulated luminescence has been observed in X-ray irradiated alkali borate and sodium silicate glasses doped with Ce3+. The emission wavelength is about 360 nm which corresponds to the 5d-4f transition of Ce3+. For the alkali borate glasses doped with Ce3+, oxygen hole center and electron trapped nearby alkali ion induced by X-ray irradiation contribute to the thermally simulated luminescence, while Sm3+ acts as an electron acceptor in the thermally stimulated luminescence of alkali borate glasses codoped with Ce3+ and Sm3+. In both cases, Ce3+ is ionized by X-ray to form Ce4+ and an electron which is trapped by an impurity level (oxygen hole center or Sm3+ in glasses with or without Sm3+, respectively). The thermal stimulation excites the electron (electron trapped nearby alkali ion or Sm3+), which transfers to the 5d level of Ce3+. The electronic transition from the 5d to the 4f levels gives rise to the emission observed. The temperature which gives the maximum emission intensity in the glow curve tends to decrease as the concentration of Na2O increases in the sodium borate glasses doped with Ce3+ and Sm3+. In contrast, the temperature corresponding to the maximum emission intensity is independent of the glass composition for the sodium silicate glasses doped with Ce3+ and Sm3+. These facts suggest that the compositional dependence of local basicity for Sm3+ ion site in sodium borate glasses is different than that in sodium silicate glasses Key Words:thermally stimulated luminescence, X-ray irradiation, oxide glass, defect, Ce3+, Sm3+