Thermoluminescence kinetic features of Eu3+ doped strontium pyrophosphate after beta irradiation

Abstract

Strontium pyrophosphate (Sr₂P₂O₇) doped with various concentrations of Eu³⁺ as a doping agent is synthesized using a combustion method and to study the thermoluminescence dosimetry [TLD] and applications. The synthesized phosphors with different concentrations of doping ions were irradiated using a ⁹⁰Sr β-source for different doses from 5 Gy to 50 Gy. TL glow curves of all the samples were measured with a heating rate of 6 K s⁻¹ from room temperature [325] to 550 K. Each time 5 mg of irradiated phosphor was taken for TL measurement. The TL exhibited by the phosphor shows a single bell-shaped curve at a peak temperature of around 415 to 420 K. From the TL glow curves the kinetic parameters of phosphors were calculated using the initial rise method (IR), whole glow peak method, peak shape method (PSM) and Kitis et al. second-order equation and also necessary statistical analysis was done. The TL glow curve parameters like activation energy (E_a), frequency factor (s) and order of kinetics (b) found from all analytical methods of all beta irradiated phosphor samples revealed that the glow curves have second-order kinetics with an activation energy of 0.90–1.10 eV and a frequency factor 10¹⁰ to 10¹¹ s⁻¹. All samples showed a linear response of TL as a function of dose from 5 Gy to 50 Gy. The sensitivity, fading effect and TL glow curve shape are unaffected by the doping concentration which implies that the phosphor shows consistent TL output except for intensity variation. The calculated TL parameters and results are consistent and well matched with the theoretical aspects.