Modeling Background Attenuation by Sample Matrix in Gamma Spectrometric Analyses
Modeling Background Attenuation by Sample Matrix in Gamma Spectrometric Analyses
复制标题
在伽马能谱分析中通过样本矩阵模拟背景衰减
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
C. Appoloni
中科院分区：
文献类型：
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作者：
R. O. Bastos;C. Appoloni
在实验室伽马光谱分析中，估计背景的程序通常高估了它。如果测量的空容器与用来装样品的容器相似，则不考虑样品矩阵的背景衰减。如果测量的是一个“空白”样品，该样品将不含放射性核素的假设通常是不正确的。这种“空白”样本的活动常常足以掩盖或压倒衰减的影响，因此背景仍然被高估。为了克服这一问题，建立了一个从空容器获取的光谱中获得衰减背景的模型。除了合理的假设之外，该模型还假定知道样品的线性衰减系数及其对光子能量和样品密度的依赖。给出了该模型对地质样品最低检测限（LLD）的影响的评价，这些地质样品被放置在完全覆盖地面的圆柱形容器中。
In laboratory gamma spectrometric analyses, the procedures for estimating background usually overestimate it. If an empty container similar to that used to hold samples is measured, it does not consider the background attenuation by sample matrix. If a “blank” sample is measured, the hypothesis that this sample will be free of radionuclides is generally not true. The activity of this “blank” sample is frequently sufficient to mask or to overwhelm the effect of attenuation so that the background remains overestimated. In order to overcome this problem, a model was developed to obtain the attenuated background from the spectrum acquired with the empty container. Beyond reasonable hypotheses, the model presumes the knowledge of the linear attenuation coefficient of the samples and its dependence on photon energy and samples densities. An evaluation of the effects of this model on the Lowest Limit of Detection (LLD) is presented for geological samples placed in cylindrical containers that completely cover the...