Characteristics of K2Ca2(SO4)3:Eu TLD nanophosphor for its applications in electron and gamma rays dosimetry

Abstract

Nanorods (~25 nm × 200 nm) of K2Ca2(SO4)3:Eu phosphor (powder) were synthesized by chemical coprecipitation method followed by annealing at 700 °C. Dimensions of nanorods were confirmed by TEM and XRD. The material (pellets) was irradiated by 60 Co gamma rays for various doses over the range of 0.1 Gy to 100 kGy and also by 6 MeV electrons at different fluences varying from 2.5×10 11 e/cm 2 to 5×10 13 e/cm 2 at room temperature. Thermoluminescence (TL) and photoluminescence (PL) of the gamma and electron irradiated phosphors were also studied. TL glow curve apparently exhibited a peak at around 152 °C with a small hump around 258 °C. The exact number of peaks in a glow curve were determined by thermal cleaning method and glow curves were further deconvoluted by CGCD method to determine trapping parameters. PL emission spectrum consisted of a single emission band at 388 nm (Eu 2+ emission) on excitation by 320 nm. The intensity of this peak increased with the electron fluence up to 5×10 12 e/cm 2 and decreases thereafter. The TL response is linear in the dose range from 0.1 Gy to 1 kGy of gamma radiation and electron fluence range from 2.5×10 11 e/cm 2 to 2.5×10 12 e/cm 2 . The electronic structures of the pristine and Eu doped K2Ca2(SO4)3 materials were analyzed by means of firstprinciples density functional theory (DFT) calculations. The dosimetric characteristics suggest that the K2Ca2(SO4)3:Eu nanophosphor can be useful for its application in radiation dosimetry, especially, for measurement of high-doses of gamma and electrons.