Transient-Diffusion Measurements of Radon: Practical Interpretation of Measured Data


          

刊名：Journal of Nuclear Science and Technology
作者：Tomozo SASAKI
Yasuyoshi GUNJI
Takao IIDA
刊号：723D0064
ISSN：0022-3131
出版年：2007
年卷期：2007, vol.44, no.7
页码：1032-1037
总页数：6
分类号：TL1
关键词：Radon diffusion；Radon diffusion coefficient；Radon；Transient-diffusion measurement
参考中译：
语种：eng
文摘：The mathematical calculation to obtain a radon diffusion coefficient from measured radon transient-diffusion data is usually done by fitting a difference equation to the data. The difference equation is obtained through transformation of the time-dependent diffusion equation based on Fick' s law. But, actual measured transient-diffusion data often have much scatter. Therefore just fitting over the whole range of the measured data through the method of least squares may not always be valid, because the method offers a mathematical interpretation rather than a physical one. Instead, the actual radon diffusion coefficients must be otherwise obtainable from measured radon transient data. Taking this viewpoint, the present paper claims that about a 90% leveling-off time is often easily discernible regardless of the shape of the radon transient curve obtained from the measured data and it can be a decisive factor for determining the radon diffusion coefficient. Alternatively, transient diffusion data during the taking-off period of the transient for a ramp-wise introduction of radon into the targeted soil column are not so scattered and can also be decisive. The present paper provides theoretical justifications to support these claims.



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