Application Of Microdosimetric Concepts In Caco3:Ce3+/Dy3+ For Megalevel Radiation Dosimetry

The 150 degrees C and 290 degrees C thermoluminescence (TL) peaks in CaCO3:Ce were attributed to generically related traps. TL process in calcites arises from O2- interstitial ions and anion vacancies created during pre-sintering which serve as hole traps and electron traps, respectively. The TL response of CaCO3:Ce is supralinear in the dose range 0.5-5 kGy due to secondary electron track interaction and sublinear beyond 5 kGy due to saturation of traps. The charge state surrounding a cation vacancy and Oi(2) in CaCO3:Ce3+ can be considered as 3 (2from oxygen and 1 from Ce3+) since Ce3+ is prone to oxidation to Ce4+ state which increases 2-track interaction during gamma-irradiation at high doses and 2-hole trapping by densely ionizing radiations. TL of CaCO3:Dy is dominated by Dy3+ emission (480 and 570 nm) and a linear TL response with dose in the range 0.5-15 kGy since track interaction probability is less.