A closed-loop method and device for measuring radon exhalation rate in emanation medium

Abstract

The invention discloses a closed-loop method and device for measuring a radon exhalation rate of a gas emitting medium. The method comprises the following steps that (1) a gas pump is opened, and theflow rate entering a gas equalizing chamber is controlled to be Q through a flow regulator; the radon concentration C0 in the external environment measured by a radon measuring instrument is taken asthe radon concentration C0 of a gas collecting hood at zero time t0; when the radon concentration in the gas collecting hood is measured, the radon concentrations C1, C2,... and Cn ( n>=5) is recordedat this time in sequence at the same time interval delta T; and (2) the solution of differential equation (shown in the description) is fitted with the above measured values, and then radon exhalation rate J is calculated. The radon exhalation rate and equivalent decay constant can be obtained by the method before the radon concentration is balanced, the closed-loop method and device for measuring the radon exhalation rate of the gas emitting medium have the advantages of short time and accurate calculation.

Description

technical field [0001] The present invention relates to a closed-loop method and device for measuring radon exhalation rate of emanation medium, in particular to a seepage device for generating controllable flow rate in particle accumulation type emanation medium and a method for determining radon exhalation rate under the action of seepage-diffusion , belonging to the technical field of nuclear radiation measurement. Background technique [0002] Radon is an inert radioactive gas, which is colorless and odorless, and widely exists in rocks, soil and groundwater. The World Health Organization (WHO) lists radon as 19 major environmental carcinogens. Radon release rate is a physical quantity to evaluate the ability of emanating media to release radon. Reasonable and scientific measurement of radon release rate and release law is a research hotspot among scholars at home and abroad. [0003] Due to the small amount of radon exhalation in the medium in the natural environment, ...

AI Technical Summary

Problems solved by technology

The gas collecting hood of this invention has no air pressure balance port, so the seepage of radon is limited, and the seepage item is ignored in the calculation. The experimental results obtained are inaccurate and do not conform to the actual mechanism of radon precipitation in porous media.

Moreover, this method can only be used when the radon concentration in the gas collecting hood tends to be balanced, and the effective decay constant and radon exhalation rate cannot be obtained quickly.

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