Thermoluminescence properties of gamma irradiated CaO: Sm3+ phosphor

Pure and samarium doped calcium oxide (CaO) is synthesized by solution combustion technique. The samples are annealed at 600 °C for two hours. X-ray diffraction (XRD) pattern of the annealed sample show cubic phase with space group Fm3m. The average crystallite size is found to be ∼54 nm. Fourier transform infra red (FTIR) spectrum exhibits bands at 424, 544 cm−1 (Ca-O bond), 875 cm−1 (C-O bond), 1460 cm−1 (C-O stretch) and 3640 cm−1 (O-H stretch). The samples are irradiated with gamma rays in a dose range 100-4000 Gy. Thermoluminescence (TL) glow curves are recorded at a linear heating rate (β) of 5 Ks−1. A prominent TL glow with a peak at 636 K is observed in undoped sample. A new TL glow with peak at ∼458 K is observed in addition to 636 K in samarium doped (1 mol%) CaO. TL glow peak intensity (Imax) at 636 K increases with γ - dose in the study range. TL emissions at 560, 600 and 640 nm are observed in doped samples corresponding to Sm3+ transitions along with pristine emissions. TL glow curves are deconvoluted to obtain kinetic parameters. The mean value of activation energy and the frequency factor of the prominent deconvoluted TL glow peak (626 K) are found to be 1.26 eV and 4.49 × 109 s−1 respectively.