Listjak Martin, Slaninka Alojz, Nečas Vladimír
VUJE, Inc., Okružná 5, 91864 Trnava, Slovakia.
Institute of Nuclear and Physical Engineering, Slovak University of Technology in Bratislava, Ilkovičova 3, 81219 Bratislava, Slovakia.
Radiat Prot Dosimetry. 2019 Dec 31;186(2-3):301-305. doi: 10.1093/rpd/ncz222.
Uncertainty analysis for nondestructive estimation of contamination depth is presented. The contamination depth was determined using the peak-to-peak method as an in-situ measurement in which gamma spectra were measured by an HPGe detector. Since exponential activity distribution is a crucial assumption of this method, the distribution profile was confirmed by laboratory tests of core drill samples. The main parameter influencing uncertainty of contamination depth is uncertainty of relaxation length. The uncertainty is composed for statistical error represented by the ratio of net peak areas and systematic error given detection efficiency of measurement setup. Systematic relative error was evaluated to be 7.45%. Statistical relative error was evaluated to 9.97% for the proposed optimum net peak area. Variability of relaxation length was identified to be very low with mean value 2 mm with standard deviation 0.73 mm. For fixed relaxation length, it should be possible to estimate contamination depth by nonspectrometric devices.
本文介绍了用于无损估计污染深度的不确定性分析。污染深度是使用峰峰值法作为现场测量来确定的，其中通过HPGe探测器测量伽马能谱。由于指数活度分布是该方法的一个关键假设，因此通过岩芯钻取样品的实验室测试来确认分布情况。影响污染深度不确定性的主要参数是弛豫长度的不确定性。该不确定性由净峰面积比表示的统计误差和测量装置给定探测效率下的系统误差组成。系统相对误差评估为7.45%。对于建议的最佳净峰面积，统计相对误差评估为9.97%。弛豫长度的变化被确定为非常低，平均值为2毫米，标准差为0.73毫米。对于固定的弛豫长度，应该可以通过非光谱设备估计污染深度。
