RADIO-OPTICAL response of cerium-doped lithium gadolinium bismuth borate glasses

Bismuth borate glasses containing lithium and gadolinium were doped with (0.1–2.5 mol%) of Ce and their optical and radiation response were investigated. These modified glasses exhibited photoluminescent properties in response to the radiations, which were evidenced by their broad-band spectral features around 378 nm due to 5d→4f transitions of the Ce3+ ions. The intensity response of these glasses increased with increasing concentration of cerium up to 2.0 mol% which decreased upon further increase in the concentration of cerium due to the quenching effect and cross-relaxation between the nearest ions. Gamma irradiation of samples with 1 and 2 Gy doses demonstrated an increase in the intensity of photoluminescence peaks with increase in the irradiation dose. The observed increase caused the formation of relatively more electron and hole trap centers that eventually led to more recombinations in the glass matrix. This enhancement in the intensity after irradiation was also proportional to the dose as expected and the photoluminescence peaks observed for the irradiation samples were broader than those of un-irradiated samples. The observed decrease in intensity after irradiation of samples with high cerium concentration (i.e. 2.5 mol%) may be linked to the energy transfer and dissipation occurring during cross-relaxation among the nearest cerium ions.