用G(E)函数法计算γ射线空气吸收剂量率

Determination of air dose rate of γ-rays by using G(E) function method

基于Φ75 mm×75 mm NaI(Tl)多道能谱仪实验测量结果,采用全谱法测定空气吸收剂量率,从理论和实验入手建立能谱剂量转换函数G(E)。选取铀、钍、钾模型和铀、钍、钾混合模型,以及人工放射性核素60Co、137Cs获取标准能谱N(E),用最小二乘法拟合得到G(E)函数的系数,并用G(E)函数法和贝克公式法估算剂量率结果与实测数据进行比对,前者的偏差小于后者。利用模型站和野外实地测量数据对该函数的准确性进行验证,误差均<10%。

G（E） function is a software method by adjusting energy response of dosimetry instrument to obtain the dose rate. In this paper, we use U, Th, K, ^60Co and ^137Cs models, and U/Th/K mixed model, to obtain the standard spectrum, and then the G（E） function by least-square method. Comparisons of the dose rate results obtained by different methods, the G（E） function method is much better than the Baker formula method. Using the data from stand model and field measurements, analytical error of the G（E） function method is less than 10%.