Method and device for measuring radon exhalation rate on medium surface

Abstract

The invention discloses a method and a device for measuring a radon exhalation rate on a medium surface. The measuring method comprises a measuring process and a calculating process. The measuring method comprises the following steps: during measurement, inversely covering a radon accumulation chamber on the surface of a medium to be measured; connecting a sealed measuring chamber with the radon accumulation chamber to form a loop; after collecting a certain time period of 5 minutes, turning on an air pump to mix the radon in the radon accumulation chamber and the measuring chamber at a smallflow rate less than 3L/min for 5 minutes, wherein at this time, the radon concentration in the measuring chamber is the radon concentration in the radon accumulation chamber at the time T; repeatedlymeasuring the radon concentration in the radon accumulation chamber to obtain a group of data of radon concentration in the radon accumulation chamber at equal time intervals by taking T which is greater than or equal to 10 minutes as a period; and solving the radon exhalation on the surface of the medium to be measured according to a theoretical formula. The measuring device consists of the radon accumulation chamber, the air pump, the measuring chamber, a secondary instrument and a drying pipe, wherein one end of the air pump is connected with the radon accumulation chamber, while the otherend is connected with the measuring chamber through a pipe; one end of the drying pipe is connected with the radon accumulation radon through a pipe, while the other end is connected with the measuring chamber through a pipe; and the secondary instrument is connected with the measuring chamber.

Description

technical field [0001] The invention relates to a nuclear radiation detection technology, in particular to a method and a device for measuring the radon exhalation rate on the surface of a medium. Background technique [0002] Radon in the air environment mainly comes from the precipitation on the surface of the medium. The main methods for measuring the precipitation rate of radon on the surface of the medium are: accumulation method and activated carbon adsorption method. The activated carbon adsorption method is to use activated carbon to adsorb the precipitated radon, and obtain the radon precipitation rate by measuring the γ spectrum generated by the decay of radon adsorbed in the activated carbon. This method takes a long time to measure and is not easy to automate; the accumulation method is mainly used for measuring Average radon exhalation rate over time. The current use of the accumulation method to measure the radon release rate on the surface of the medium does ...

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Problems solved by technology

The activated carbon adsorption method is to use activated carbon to adsorb the precipitated radon, and obtain the radon precipitation rate by measuring the γ spectrum generated by the decay of radon adsorbed in the activated carbon. This method takes a long time to measure and is not easy to automate; the accumulation method is mainly used for measuring Average radon exhalation rate over time

The current use of the accumulation method to measure the radon release rate on the surface of the medium does not consider the impact of leakage and back diffusion caused by the concentration accumulation of radon after the release, nor does it consider the interference of environmental radon and thoron (including the environment and the release of the medium surface) , the measurement results obtained have a large error

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, but it not only has the above disadvantages, but also it is difficult to eliminate the influence of humidity

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