Method and device for measuring radon exhalation rate in open loop way

Abstract

The invention relates to a method and a device for measuring a ring-opening radon exhalation rate in an open loop way. The method comprises a measurement process and a calculation method. When the measurement is performed, after a radon collecting cover is covered on the surface of a medium to be measured, ends A and B of an electromagnetic tee valve are connected; a constant flow pump is opened to continuously suck in clean air from outside; when exhaust is performed for a given reference balance time, ends A and C of the electromagnetic tee valve are connected; when exhaust is performed to allow radon concentration in a measuring room to be consistent with that in the radon collecting cover, the constant flow pump and the electromagnetic tee valve are closed and measurement is performed to obtain a balanced radon concentration C; and the radon exhalation rate J is calculated through the balanced radon concentration C. The measuring device provided by the invention consists of the radon collecting cover, the sampling constant flow pump, high-efficiency 222RN and 220Rn sub-filters, a drier, the electromagnetic tee valve and a measuring module, wherein the measuring module comprises a measuring chamber, a semiconductor probe, a secondary instrument, a preamplifier and a high-voltage module.

Description

technical field [0001] The invention relates to a nuclear radiation detection technology, in particular to a method and a measuring device for measuring the radon exhalation rate on the surface of a medium. Background technique [0002] The radon exhalation rate refers to the activity of radon that is exuded into the air through a unit area of ​​the medium surface in a unit time. Measuring the radon exhalation rate on the surface of the medium is one of the important means to evaluate the natural radiation level, judge whether the radon of building materials meets the standard, and evaluate whether the decommissioning treatment of uranium mines is qualified. Common methods for measuring radon exhalation rate include accumulation method and activated carbon adsorption method. Among them, the activated carbon adsorption method needs a long measurement time, and the measurement results cannot be obtained quickly; the accumulation method is to buckle a radon collection cover on...

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Problems solved by technology

Among them, the activated carbon adsorption method needs a long measurement time, and the measurement results cannot be obtained quickly; the accumulation method is to buckle a radon collection cover on the surface of the emanation medium, and seal the surrounding area with an airtight material, so that the radon precipitated on the surface of the measured medium is collected. Radon hood collection, the radon concentration in the hood increases with time, and the radon exhalation rate can be calculated by measuring the change of radon concentration in the hood

Although the electrostatic collection type radon exhalation rate meter using the accumulation method has been widely used because of its simplicity, rapidity, and instant measurement results, this method should not only consider the influence of leakage and back diffusion, but also 218 Po unbalance correction, so the calculation is more complicated

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