Synthesis and characterization of Dy3Â + doped lithium borate glass for thermoluminescence dosimetry

Lithium borate glass systems were synthesized to study their feasibility for measuring high radiation doses using thermoluminescence (TL) technique. Lithium borate glass with a composition (mol%) of 30Li2O-70B2O3 was prepared by conventional melt quenched technique. To see the effect of Dy3 + on thermoluminescence, photoluminescence and thermal properties of the glass, 0.5 wt% of Dy2O3 was added prior to the glass making. One more glass with exact lithium tetraboarte (Li2B4O7) composition doped with 0.5 wt% Dy2O3 was also prepared. Thermo-physical properties like density, and glass transition did not show significant changes with addition of Dy2O3. However, optical properties like band gap, UV visible absorption and photoluminescence showed substantial changes. The optical band gap decrease from 3.05 to 2.78 eV with addition of Dy2O3. Photoluminescence (PL) analysis showed a broad emission at around 475 nm in all the glasses and very sharp intense emission at 570 nm for Dy2O3 doped glasses. After gamma irradiation in the dose range of 0.5-5 kGy the samples exhibited TL peak at around 136 and 152 °C for Dy2O3 doped lithium borate and tetraborate samples, respectively. A linear dose response in TL intensity was also observed which was useful for quantitative estimation of absorbed dose.