Thermoluminescence characteristics of gamma-irradiated nano-alumina

Abstract

The focus of this study lies in exploring the properties of thermoluminescence (TL) in nano-alumina, including the correlation between TL intensity and absorbed dose, identification of individual luminescence peaks, and investigation of trap parameters for potential dosimetry applications. The samples were irradiated by 60Co with doses ranging from 530 to 2646 Gy. Micro-sized α-Al2O3 had a prominent dosimetry peak at maximum temperature Tm = 435 K. Nano-α-Al2O3 samples with 40 and 50 nm particle sizes exhibited a TL luminescence glow curve, with the main dosimetry peak in the low-temperature region and a complex structure at higher temperatures (above 500 K). The observed maximum of the main dosimetry peak depended on the nanoparticle size and was 460 K for the sample with particle size of 40 nm and 467 K for 50 nm. The main dosimetry peak was described by the superposition of the two peaks.A computerized glow curve deconvolution method was applied to determine the parameters of the traps responsible for TL using the Microsoft Windows-operated GlowFit program, assuming first-order kinetics. The found values of the activation energies were 0.97 ± 0.01 eV for the trapping center responsible for the peak with Tm = 458 ± 3 K and, accordingly, 1.05 eV for the peak with Tm = 473 ± 3 K. The estimated values of the frequency factor were s ≈ 1.01 × 1010 and 1.3 × 1010 s−1 for the peak with Tm = 458 ± 3 K, and 2.06 × 1011 s−1 for the peak with Tm = 473 ± 3K, respectively. The lifetime for the traps in nano-α-Al2O3 was estimated as 43–56 days for the first trap and approximately 65 days for the second trap. It is assumed that these traps are responsible for TL emission at the low-temperature part of the glow curve.