Effect of europium concentration on gamma ray exposed thermoluminescence behaviour of LiF: Sm3+, Dy3+, Eu3+ nanophosphor

LiF: 0.05 mol% Sm3+, 0.08 mol% Dy3+ with varying concentrations of Eu3+ (x = 0.02, 0.04, 0.06, 0.08 mol%) nanophosphors were synthesized by chemical co-precipitation method at fixed 8 pH value, to study the thermoluminescence behaviour for dosimetric applications. XRD confirmed the cubical crystalline phase of the nanophosphors. The average size of the nanophosphor particle calculated as 45 nm from XRD was well confirmed by TEM. The synthesized nanophosphors were exposed by doses of 0.1 kGy to 30 kGy from Co-60 gamma- source. For recording TL glow curves, 5 mg of exposed nanophosphor was taken each time and heated at the constant heating rate of 5 K s(-1) for the temperature range 323 K-673 K. The thermoluminescence revealed a prominent peak at temperature around 398 K to 412 K. The glow curves were deconvoluted using TLAna1 program and the trapping parameters viz. activation energy (E), order of kinetics (b) and frequency factor (s) were calculated by using Chen's peak shape method. Nanophosphors indicated a linear behaviour of TL for the dose from 0.1 kGy to 30 kGy and was described by using track interaction model (TIM).The activation energies ranged between 0.71 to 2.24 eV and the frequency factor(s) were in the range 7.09 x 10(-4) to 1.74 x 10(18) s(-1).