Study of gamma ray induced defect centers in MnO doped calcium fluoro borophosphate glasses by means of EPR spectroscopy

• CaF2–P2O5–B2O3 glasses mixed with 0.2 mol% of MnO were prepared.
• Samples were exposed to γ-rays for dose rate of 1.5 kGy/h for two hours.
• ESR spectra were recorded in the temperature range 300–475 K.
• The spectra exhibited near axially symmetric signal with doublet hyperfine structure.
• The signal is attributed to PO42- radical formed by trapped hole O− orbital.

CaF2–P2O5–B2O3 glasses mixed with 0.2 mol% of MnO were prepared. The prepared samples were exposed to γ-rays for dose rate of 1.5 kGy/h for two hours and their EPR spectra were recorded in the temperature range 300–475 K. The spectra of pure as well as MnO doped glass samples exhibited a new and nearly axially symmetric (g⊥=2.0085 and g||=2.0090, A⊥= 34 G and A||= 52 G) signal with doublet hyperfine structure. The signal is attributed to PO42- radical formed by trapped hole on non-bonding orbital of oxygen. The analysis of these data together with thermoluminescence (TL) studies indicated that PO42- radical plays a crucial role in TL emission.

EPR spectra recorded at 475 K with super imposition of TL emission for calcium fluoro boro phosphate glass.Figure optionsDownload as PowerPoint slide