Method and device for valuing <220>Rn concentration reference level by utilizing low pressure scintillation chamber

Abstract

The invention discloses a method and a device for valuing a <220>Rn concentration reference level by utilizing a low pressure scintillation chamber. The device consists of a <220>Rn chamber, a flow meter, a regulating valve, a filter, the scintillation chamber, a scintillation chamber measurement device, a vacuum meter and a sampling pump. The method comprises the following steps of: in measurement, opening the sampling pump, and regulating the regulating valve to circulate air containing <220>Rn in a loop at a certain flow rate, thereby balancing the <220>Rn in the scintillation chamber and the <220>Rn in a measurement environment, wherein an air pressure in the scintillation chamber is P which is lower than an atmospheric pressure; then starting a scintillation chamber measurement system, performing counting for the counting time T of 5 to 30min to obtain a count N of which a unit time background count is N0 by using the scintillation chamber measurement device, and converting <220>Rn concentration under the next atmospheric pressure in the scintillation chamber; and performing reverse calculation to obtain the <220>Rn concentration in air by combining the circulation time delayof the <220>Rn in a pipeline and the scintillation chamber.

Description

technical field [0001] The invention relates to a nuclear radiation detection technology, in particular to a low-voltage scintillation chamber 220 A method and device for determining a reference level of Rn concentration. Background technique [0002] In recent years, the environmental 220 Interest in surveys of Rn levels is clearly on the rise, and the survey found that some environments 220 The concentration of Rn is relatively high, while in the soil of our country 232 Th content is significantly higher than the world average. because 220 The half-life of Rn is very short, it is difficult to establish a stable and uniform 220 Rn level environment, plus for 220 The hazards of Rn are not taken seriously enough, so 220 The measurement technique of Rn and its progeny is far less than that of radon ( 222 Rn) so convenient and perfect. current pair 220 The methods for determining the concentration of Rn gas are mainly gamma spectrum method, small scintillation chamber...

AI Technical Summary

Problems solved by technology

The use of gamma spectroscopy needs to be adsorbed with an adsorbent material first. 220 Rn, then take out the measurement, the measurement system is complicated, the measurement time is long, and it is not easy to realize automation

Using the small scintillation chamber method, due to its small size, results in the same 220 Under the concentration of Rn, its count is less than that of the standard scintillation chamber, which increases the statistical fluctuation, and the small scintillation chamber is a non-standard product, with high cost and poor consistency

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