Thermoluminescence of 9 MeV electron irradiated CaAl2O4:Sm3+ phosphor and its implication in dosimetry.

This work reports the Thermoluminescence (TL) of 9 MeV electron irradiated nanocrystalline CaAl₂O₄: Sm³⁺ phosphor. In the dose range, 0.5 to 5.0 Gy excitation in all the cases the profile of the TL curves are similar showing prominent peaks in the region 191 ± 1.87˚C and 398 ± 6.44˚C. Whole curve fitting reveals the existence of six discrete traps levels of depth 0.84 ± 0.01eV, 0.92 ± 0.00 eV, 1.00 ± 0.01 eV, 1.14 ± 0.02 eV, 1.26 ± 0.01 eV and 1.40 ± 0.01eV. All the peaks follow non-first order (b≠ 1) kinetics with frequency factor(s) in the range 10⁹ ≤ s ≤ 10¹⁰ s^-1. Electron lifetimes (τ) of charge in these traps are 5.67±0.97 Days, 13.01 ± 3.67 Days, 10.43 ± 4.60 Years, 5.92 ± 4.60×10⁰³ Years, 1.16 ± 0.68×10⁰⁶ Years, 2.02 ± 0.57×10⁰⁸ Years. This shows that the intense TL peaks a 1.40 ± 0.01eV at 398 ± 6.44˚C may be optimized for application in clinical dosimetry of electron beam therapy. [ABSTRACT FROM AUTHOR]