作者机构：
[Tan, Yanliang] Hengyang Normal Univ, Dept Phys & Elect, Hengyang, Peoples R China.;[Tan, Yanliang; Xiao, Detao] Univ South China, Sch Nucl Sci & Technol, Hengyang, Peoples R China.
通讯机构：
[Tan, Yanliang] H;Hengyang Normal Univ, Dept Phys & Elect, Hengyang, Peoples R China.
关键词：
RAD7;Soil;Thoron exhalation rate
摘要：
Thoron exhalation rate can be obtained through the combination of the "accumulation chamber" technique and RAD7. Thoron's rapid decay causes the intake path and the air flow rate to become important factors in calibration. In field conditions, since the flow rate of the internal pump in RAD7 will change as the voltage of the battery decreases, the big drying tube is more suitable for a long measurement than the small drying tube. We developed the method for recalibration of the thoron concentration reading of RAD7 based on the calibration factor for 222Rn, and obtained the thoron exhalation rate from soil surface near by the Radon Laboratory of the University of South China. This method can be applied to develop and improve instruments for measuring the radon exhalation rate.
作者机构：
[申超; 肖德涛; 陈凌] School of Nuclear Science and Technology, University of South China, Hengyang 421001, China;[谭延亮] Department of Physics and Electronic Information Science, Hengyang Normal University, Hengyang 421008, China;[陈凌] China Institute of Atomic Energy, P. O. Box 275-24, Beijing 102413, China
通讯机构：
School of Nuclear Science and Technology, University of South China, China
摘要：
The radon exhalation rate from the medium surface is commonly derived using a scheme involving a radon detector and an accumulation chamber. The accumulation chamber accumulates the radon gas to make its concentration level inside the chamber detectable by the radon detector in the scheme. The common calculation method for deriving the exhalation rate is based on an assumption that the radon concentrations in the detector's internal cell and that in the accumulation chamber become equal with sufficient accumulation time. However, based on our recent experiments, this method tends to underestimate the actual exhalation rates as generated by our simulation facility. To correct this, we develop a new method for computing the exhalation rate based on the non-equilibrium concept. This paper presents the new method.
期刊：
Review of Scientific Instruments,2011年82(4):043503 ISSN：0034-6748
通讯作者：
Tan, Yanliang
作者机构：
[Tan, Yanliang] Hengyang Normal Univ, Dept Phys & Elect, Hengyang 421008, Hunan, Peoples R China.;[Tan, Yanliang; Xiao, Detao] Univ S China, Sch Nucl Sci & Technol, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Tan, Yanliang] H;Hengyang Normal Univ, Dept Phys & Elect, Hengyang 421008, Hunan, Peoples R China.
关键词：
chemical variables measurement, instruments, polonium, radon
摘要：
Several measurements of the radon concentration are performed by RAD7 in the University of South China. We find that 30-40 min is needed for RAD7 for tracing the concentration of the standard radon chamber. There are two reasons. The first is that the sufficient time of air cycle is needed for the radon concentration in internal cell of RAD7 equal to that of the environment; and the second is that the sufficient decay time is needed for the (218)Po concentration in internal cell of RAD7 equal to that of the radon. We used a zeroth order approximation to describe the evolution of the environment radon concentration, and obtained a novel algorithm for quick and continuous tracing the change of radon concentration. The corrected radon concentration obtained through this method is in good agreement with the reference value. This method can be applied to develop and improve the instruments for tracing the change of radon concentration quickly. (C) 2011 American Institute of Physics. [doi:10.1063/1.3572271]
