Color centers of CaF2 crystals subjected to three high-dose gamma-ray irradiation treatments were studied. Three absorption bands at 349, 409 and 478 nm are ascribed to the F interstitials through the variation in dif...Color centers of CaF2 crystals subjected to three high-dose gamma-ray irradiation treatments were studied. Three absorption bands at 349, 409 and 478 nm are ascribed to the F interstitials through the variation in difference additional absorption values. The transformation of interstitial F atoms to F ions (Fi-) is demonstrated using data with increasing radiation dose. The decrease in the 600 nm absorption band and the occurrence of the 580 nm band correspond to F2+ center conversion to F center. The complex (F^--Fi0 ) might be associated with the 962 and 1196 nm bands.展开更多
Color center concentrations of the Al2O3 crystal grown by temperature gradient techniques were calculated from Gaussian fits to absorption spectra. The concentrations for F- and F + -centers at 204, 232, and 255 nm we...Color center concentrations of the Al2O3 crystal grown by temperature gradient techniques were calculated from Gaussian fits to absorption spectra. The concentrations for F- and F + -centers at 204, 232, and 255 nm were determined to be 1.361×10 17 , 0.098×10 17 , and 0.325×10 17cm-3 , respectively. Studies have shown that the thermoluminescence (TL) glow curve exhibits a prominent 450 K peak that matches well the first-order fitting curve. The thermal activation energy E and frequency factor s of the trap were determined to be 0.94456±0.00545 eV and 5.8703×10 11 s-1 . With this theoretical analysis, a simple one-trap/one-center TL model is presented to provide a theoretical explanation of the TL process.展开更多
文摘Color centers of CaF2 crystals subjected to three high-dose gamma-ray irradiation treatments were studied. Three absorption bands at 349, 409 and 478 nm are ascribed to the F interstitials through the variation in difference additional absorption values. The transformation of interstitial F atoms to F ions (Fi-) is demonstrated using data with increasing radiation dose. The decrease in the 600 nm absorption band and the occurrence of the 580 nm band correspond to F2+ center conversion to F center. The complex (F^--Fi0 ) might be associated with the 962 and 1196 nm bands.
文摘Color center concentrations of the Al2O3 crystal grown by temperature gradient techniques were calculated from Gaussian fits to absorption spectra. The concentrations for F- and F + -centers at 204, 232, and 255 nm were determined to be 1.361×10 17 , 0.098×10 17 , and 0.325×10 17cm-3 , respectively. Studies have shown that the thermoluminescence (TL) glow curve exhibits a prominent 450 K peak that matches well the first-order fitting curve. The thermal activation energy E and frequency factor s of the trap were determined to be 0.94456±0.00545 eV and 5.8703×10 11 s-1 . With this theoretical analysis, a simple one-trap/one-center TL model is presented to provide a theoretical explanation of the TL process.
