目的 通过对大剂量照射后的热释光探测器(LiF:Mg,Cu,P)进行研究,探讨热释光探测器性能是否发生改变.方法 采用热释光退火炉对大剂量辐照后的热释光探测器进行退火,直至完全退火,然后用137Cs辐照仪照射固定剂量(0.5 Gy),验证热释光探测器的准确性.结果 大剂量照射后的热释光探测器在常规240℃条件下不能完全退火,在400℃高温条件下可以完全退火;退火后的热释光探测器经137Cs辐照仪辐照0.5 Gy后测量结果明显偏小,探测器的剂量响应和分散性也发生了明显改变.结论 经过大于5 Gy电子辐照场照射后,热释光探测器的晶体结构发生了改变,出现了240℃以上高温峰,导致常规温度下不能完全退火.因此,大剂量照射后的热释光探测器不能再用于剂量测定.
Objective To investigate effect of high dose irradiation on the performances of thermolumines-cence detectors (LiF:Mg, Cu, P). Methods The high-dose irradiated thermoluminescence detector was annealed by a thermoluminescence annealing furnace until the annealing was completed, and then the annealed thermoluminescent detector was irradiated 0.5Gy by 137Cs irradiator to verify the accuracy of the thermoluminescentdetector. Results The thermoluminescence detector after high-dose irradiation could not be completely annealed under the temperature condition of 240 ℃, and it could be completely annealed at a high temperature as 400℃. After 0.5 Gy irradiation by 137Cs irradiator, the measurement results of the annealed thermoluminescence detector were significantly smaller, and the dose response and dispersion of the detector were also changed significantly. Conclusions After a more than 5 Gy irradiation, the crystal structure of the thermoluminescence detector has changed, and a high temperature peak above 240 ℃ has appeared, which leads to the failure to completely anneal at normal temperature. Therefore, the thermoluminescence detector can no longer be used for dosimetry after high-dose irradiation.