Influence of copper ions on thermoluminescence characteristics of CaF2–B2O3–P2O5 glass system

Thermoluminescence (TL) characteristics of γ−ray irradiated calcium fluoro borophosphate glasses doped with different concentrations of CuO (0.2–1 mol%) have been studied in the temperature range 30–300 °C. The γ−ray dose is varied from 0.25 kGy to 10 kGy. The glow curves of these glasses have exhibited a dosimetric peak at about 200 °C and a high temperature peak at about 300 °C. The glasses doped with 0.2 mol% of CuO have exhibited maximum TL light output. The increase of dopant concentration beyond 0.2 mol% caused the inhibition of TL emission drastically with shifting of peak positions towards higher temperatures. The probable mechanism responsible for quenching of TL emission in these glasses has been explained based on the variations in the valence state of copper ions with the aid of optical absorption spectra. The dose response of 0.2 mol% CuO doped borophosphate glass samples showed linear behavior within the dose range of 0.25 to 4 kGy. Samples containing higher concentrations of CuO (>0.2 mol%) were found to be not suitable for radiation dosimetry within 10 kGy dose.