Optical properties of gamma-irradiated sodium diborate glasses containing copper and cerium

Absorption spectra of Na2B4O7-CuO and Na2B4O7-CeO2 binary systems as well as the Na2B4O7-CuO-CeO2 ternary system have been measured and effects of dopant concentration and gamma-dose have been studied. The radiation induced band at 550 nm in the base diborate glass is suppressed by the presence of cerium due to the transformation of Ce4+ to Ce3+. The released electrons are then used to annihilate positive holes responsible for this band. Copper in the binary glass system gives rise to its characteristic band at 780 nm due to the cupric ions either originally present as Cu2+ ions or Cu++ ions induced by irradiation. Absorption of the irradiated ternary glass system is controlled by the cerium concentration when it exceeds that of copper in the glass, while the copper ions dominate the absorption process at a copper concentration exceeding that of cerium.