Anomalous heating rate response of beta irradiated Sm3+ and Tb3+ doped BaAl2O4 phosphors
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Date
2018
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Abstract
The stuffed derivative of the tridymite structure, the oxide BaAl2O4 has been regarded as a long persistent phosphor. Thermoluminescence (TL) glow curve peaks of thin pellet samples of undoped and, Sm3+ and Tb3+ doped BaAl2O4 prepared by combustion method was reported. The structure of the compounds was monitored by X-ray diffraction and found a single-phase compound with a hexagonal structure. Performing a series of TL measurements for the temperature range from room temperature to 400 °C, the effect of beta radiation dose on TL response, various TL heating rate (HR) properties of undoped and Sm3+ and Tb3+ doped BaAl2O4 phosphors were investigated. Peak shape method was also utilized to assess the trap parameters. The activation energy of the main peak at 128 °C was found to be 0.97 eV. TL glow curves obtained from undoped and Tb3+ doped BaAl2O4 decrease with increasing HR value (varying from 0.5 to 15 °C s−1) in a way matching with thermal quenching effect. Contrary to expectations, anomalous HR dependence was observed on Sm3+ doped BaAl2O4 sample and a semi-localized transition model has been used in order to explain such behaviour. © 2018 Elsevier B.V.
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Activation energy , Aluminum compounds , Electron transitions , Heating rate , Phosphors , Rare earths , Samarium compounds , Silica , Silicate minerals , Terbium compounds , Thermoluminescence , Anomalous heating , BaAl2O4 , Hexagonal structures , Long persistent phosphor , Peak shape methods , Semi-localized transitions , Single-phase compound , Temperature range , Barium compounds