Thermoluminescence spectra of gamma-ray-irradiated Al2O3

Thermoluminescence (TL) spectra of the crystal system Al2O3 and the Linde Al2O3 irradiated with Ir-192 gamma-ray were measured over the temperature interval of 300 similar to 540 K and the spectral range of 300 similar to 800 nm. The TL glow curve of the crystal system sample has one peak at 363 K, while the Linde sample has two peaks at 385 K and 508 K with two small shoulders at 373 K and 410 K, respectively. For the TL glow curve with the single peak located at 363 K, the activation energy and the escape frequency factor were calculated by a peak shape and a curve fitting method. The emission spectrum of the crystal system sample at 363 K was split into 1.90-eV, 3.00-eV, and 3.50-eV emission bands. The average frequency energy, h (v) over bar, and the Huang-Rhys factor, s, for the 3.00-eV emission band were calculated to be 324 cm(-1) and 16.6, respectively. The emission spectra of the Linde sample, both at 385 K and 508 K, were resolved into 1.78-eV and 1.90-eV emission bands; besides, an additional 3.80-eV emission band existed in the spectrum at 385 K. Cr3+ impurities were initially contained in both the crystal system sample and the Linde sample, but the former originally F-center-type defects and the latter F+-center-type defects.