Revision for measuring radon exhalation rate in open loop

Abstract

We propose a novel method for quickly measuring the radon exhalation rate in open loop. We first obtain the temporal variation of radon concentration in the internal cell of the RAD7 by analyzing the work principle of RAD7. We then obtain the temporal variation of radon concentration in the ventilation-type accumulation chamber when the effects of leakage and back diffusion are neglected. This method uses the measured value before the radon concentration in the ventilation-type accumulation chamber reaches a steady state. The diameter of the air input tube to the ventilation-type accumulation is large enough to keep the differential pressure in the accumulation chamber and outdoors negligible. Short cycle time and large flow rate will be appropriate for reducing measurement error. Several radon exhalation rate measurements of the medium surface have been performed in the Radon Laboratory of the University of South China. The radon exhalation rates obtained by verification experiments are in good agreement with the reference value. This method can be applied to develop and improve the instruments for measuring radon exhalation rate.

Comparison of two models for measuring radon exhalation rate with a ventilation chamber by numerical simulation

“…The radon exhalation rate can be calculated with the measured data and the physics model. The "ventilation chamber" technique is simple [11,12], and it is suitable for surveying the radon exhalation rate continuously [13]. Two models can be used to measure the radon exhalation rate with a ventilation chamber.…”

“…The first is the custom model, in which the radon concentration inside the ventilation chamber needs to be stable, prior to the calculation of the radon exhalation rate through eq. (1.1) [12]:…”