Equilibration correction of temporal measurements for sudden 222Rn concentration changes
Equilibration correction of temporal measurements for sudden 222Rn concentration changes
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DOI：
10.1088/1748-0221/11/02/t02002
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发表时间：
2016-02
影响因子：
1.3
通讯作者：
Y. Tan;S. Tokonami;H. Liu;K. Kearfott
中科院分区：
文献类型：
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作者：
Y. Tan;S. Tokonami;H. Liu;K. Kearfott
222Rn和220Rn可作为地下水或海底泉水的示踪剂，水中的222Rn还可指示某些地区的室内氡问题。222Rn的半衰期足够长，在相对较长距离的传输过程中，其浓度可能仍然很大，而220Rn的半衰期则不够长。以前的研究表明，在水流量为17.5Min−1的情况下，氡达到气体平衡大约需要15分钟，这大约相当于222Rn-218Po对达到放射性平衡所需的时间，在测量氡浓度突变方面是有限的。在这项工作中，应用了一种算法来改进野外环境中氡浓度的连续跟踪。应用该分析方法分析的实验室实验结果表明，它能够立即识别浓度急剧增加的情况。本文发现，由于测量不确定度的原因，氡浓度的急剧下降会导致不正确的校正值，并提出了在这种情况下用零值代替负值来减少不确定度的方法。
222Rn and 220Rn can be used as tracers of groundwater or submarine springs, and 222Rn in water also could indicate indoor radon problems in some regions. The half-life of 222Rn is long enough that its concentration may remain significant during transit over relatively long distances, while that of 220Rn is not. Prior research revealed that it took about 15 min for the radon to achieve gas equilibrium at a water flow rate of 17.5 L min−1, which is approximately equivalent to the time required for the 222Rn-218Po pair to approach radioactive equilibrium and is limiting in terms of measurements of sudden radon concentration change. In this work, an algorithm is applied to improve the continuous tracing of radon concentrations in the field environment. Results of a laboratory experiment analyzed applying the analysis method illustrated its ability to allow immediate identification of sharp concentration increases. In this paper we find that a precipitous drop in radon concentrations lead to improper corrected values as the result of measurement uncertainties prior to the drop, and a method using zero instead negative values for reducing the uncertainties under such condition also is proposed.