影响窗玻璃γ辐射响应的电子自旋共振波谱研究

为更好应用于人员剂量估算和事故等级测定,探索了影响窗玻璃电子自旋共振波谱剂量学性质的因素。实验将窗玻璃处理成不同粒度大小,分别研究研磨处理对本底信号和辐射信号的影响。给予窗玻璃样本不同照射剂量,存储在不同条件下,观察温度、光线、时间等对电子自旋共振波谱(ESR)信号的影响。对比了来源不同的窗玻璃剂量响应曲线和最小检测剂量。结果表明,前期样本处理对窗玻璃辐射信号并无明显影响,但会产生机械信号;温度越高,窗玻璃辐射信号越不稳定。高温加热(≥200 ℃,≥5 min)可使照射后的ESR信号衰退至本底信号;透明袋-灯光和黑袋存储条件下的样本结果大致相同:11小时信号强度衰减9%左右,150小时衰减约18%。透明袋-阳光样品:11小时信号衰减了17%,150小时衰减38%。三种存储条件下的样本在150小时左右之后均达到稳定状态;窗玻璃样品在g=2.005 7处ESR信号与吸收剂量线性相关,线性相关性系数因来源于不同生产厂家而有差异。窗玻璃最小检测剂量是4~5 Gy。因此,在窗玻璃作为剂量计的实践中,注意以上问题,建立合理的剂量评估操作程序,可以估算出更为准确的结果。

ESR response of window glass to γ radiation

The factors affecting ESR dosimetry of window glass were explored for better application in personal dose estimation and accident grade determination. The effect of sample processing on the background signal and the radiation signal was studied by grinding the window glass into different particle sizes. The window glass samples were given different dose of radiation, and were stored under different conditions. The effects of temperature, light, and time on the ESR signal were observed. The dose response curves and the minimum detection doses of window glass from different manufacturers were compared. The results show that the sample processing has no obvious effect on the radiation signal, but it will produce mechanical signal; the higher the temperature, the more unstable the radiation signal. High-temperature heating (≥200 ℃, ≥5 min) can decay the ESR radiation signal to background level. The results of samples(transparent bag-lamplight storage,and black bag storage) are approximately the same: after 11 hours, the signal intensity reduced about 9%; after 150 hours, the signal intensity reduced about 18%.Signal decayed 17% after 11 hours and decayed 38% after 150 hours for samples with transparent bag-sunlight storage. The samples under the three storage conditions all reached to a stable state after about 150 hours; the ESR signal of the window glass sample at g=2.0057 is linearly related to the absorbed dose, and the linear correlation coefficients varied with different manufacturers. The minimum detectable dose is 4-5 Gy. Therefore, in the practice of window glass as dosimeter, a reasonable dose assessment procedure should be set up for more accurate results.