Luminescence properties of Tb and Eu activated CaSO4 phosphor. (February 2023) - Guckan, V.
Abstract: In this study, the precipitation technique was used for the synthesis of calcium sulfate (CaSO4 ) phosphor. Eu and Tb lanthanide ions were included as dopants to achieve the high-performance phosphorous material. We observed the influence of dopant contents controlling luminescence intensity of CaSO4 :Tb, Eu phosphor. The X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques were used to characterize the structural analyses and surface morphology of the material, respectively. Spectroscopic analysis was performed using the radioluminescence (RL) measurement. Under X-ray excitation, the strongest emission line located at ∼369 nm was assigned as the F 6 4 D 1 → F 7 4 5 transition of Eu 2+ ions. Eu 3+ ions showed emissions at 592, 618, and 696 nm which originate its D 0 5 → F j 7, ( j = 1 − 3 ) transitions. The probable correlation between the OSL signal and the peaks in the TL glow curve was also examined. The OSL signal was found to be originated from the traps between 80 and 360 °C. The OSL dose-response of the CaSO4 :Tb0.01%, Eu0.1% was found to be linear up to 20 Gy. The minimum detectable dose (MDD) value was estimated at the mGy level. The fading amount was 11% after 4 weeks of storage in dark. The lifetimes of the OSL decay components were determined as 0.06, 0.98, and 14.68 s using the curve fitting method. The conclusion from these data verifies the suitability of using CaSO4 :Tb0.01%, Eu0.1% phosphor for radiation dosimetry, and the possibility of its development for this use. Highlights: The luminescence properties of Tb activated CaSO4 :Eu phosphor were characterized by RL, TL and OSL methods. Dosimetric properties of CaSO4 :Tb, Eu samples were examined. TL curve recorded at 5 °C/s produces two glow peaks at ∼180 and 220 °C in VIS region. There are four electron traps (E = 0.79, 1.03, 1.17 and 1.38 eV). OSL decay curve of the sample consists a fast-, medium- and slow-components with first order kinetic approximation.