Akselrod A E, Akselrod M S
Landauer Inc., Stillwater Crystal Growth Division, OK 74074, USA.
Radiat Prot Dosimetry. 2002;100(1-4):217-20. doi: 10.1093/oxfordjournals.rpd.a005850.
Al2O3:C single crystals are known to exhibit some variation of their thermoluminescence (TL) glow curve shape from sample to sample. This variation is attributed to the fact that the TL peak in Al2O3:C is produced by the set of several traps. It is important to understand what part of the trap distribution correlates with the optically stimulated luminescence (OSL) process in this material. Crystals with a difference in the full-width, half-maximum (FWHM) of the TL peak as big as 30% and crystals having double-peak glow curves were used in this study. It was found that bleaching with a wavelength longer than 525 nm depletes mostly the low temperature part of the TL glow curve, leaving the high temperature peak unaffected. It was shown that when the pre-irradiation annealing temperature was increased from 500 to 1000 degrees C, the high temperature part of the abnormal double peak disappears. The phototransferred luminescence (PTTL) processes and conversion of F and F+ centres were also studied for samples having different glow curves shape. The practical aspect of this research is important for OSL dosimetry, because such crystals with wide or double TL peak can make it difficult to bleach OSL dosemeters for very low dose measurements.
已知Al2O3:C单晶的热释光（TL）发光曲线形状在不同样品之间存在一些变化。这种变化归因于Al2O3:C中的TL峰是由多个陷阱产生的。了解陷阱分布的哪一部分与该材料中的光激发发光（OSL）过程相关很重要。本研究使用了TL峰半高宽（FWHM）差异高达30%的晶体以及具有双峰发光曲线的晶体。结果发现，用波长大于525 nm的光进行漂白主要消耗TL发光曲线的低温部分，而高温峰不受影响。结果表明，当预辐照退火温度从500℃提高到1000℃时，异常双峰的高温部分消失。还对具有不同发光曲线形状的样品研究了光转移发光（PTTL）过程以及F和F+中心的转换。这项研究的实际意义对于OSL剂量测定很重要，因为这种具有宽TL峰或双峰的晶体可能会使极低剂量测量的OSL剂量计难以漂白。
