Fujita Hiroki, Hashimoto Tetsuo
Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1194, Japan.
Radiat Prot Dosimetry. 2007;123(2):143-7. doi: 10.1093/rpd/ncl108. Epub 2006 Aug 25.
To develop retrospective dosimetry of unexpected radiation accident, basic studies on violet thermoluminescence (VTL) phenomena were conducted using natural quartz grains. All VTL glowcurves of as-received samples did not exhibit peaks <250 degrees C, although for artificially irradiated quartz samples there were VTL peaks in the temperature region <250 degrees C. Therefore, accident doses could be estimated without the interference of naturally accumulated doses by VTL measurements from natural quartz. The mean lives of VTL were evaluated by the various heating rates method and the range of values was found to be between some days and ten thousands of years depending on each peak. Especially, the mean life of VTL peak at 200 degrees C was years order. Furthermore, the lower detection limit was calculated to be tens of mGy from the response curve. This value was lower than that of other methods such as ESR dosimetry. From these results, we conclude that VTL dosimetry can be preferred for accidental evaluation.
为开展意外辐射事故的回顾性剂量测定，使用天然石英颗粒对紫光热释光（VTL）现象进行了基础研究。尽管人工辐照石英样品在低于250℃的温度区域存在VTL峰，但所接收样品的所有VTL发光曲线在低于250℃时均未出现峰值。因此，通过对天然石英进行VTL测量，可以在不受自然累积剂量干扰的情况下估算事故剂量。采用不同加热速率法评估了VTL的平均寿命，发现其值范围在几天到数万年之间，具体取决于每个峰。特别是，200℃时VTL峰的平均寿命为数年量级。此外，根据响应曲线计算出的最低检测限为几十毫戈瑞。该值低于电子自旋共振剂量测定等其他方法的值。基于这些结果，我们得出结论，VTL剂量测定法在事故评估中更具优势。
