Device and method for measuring ionization rate of water vapor molecules in air

Abstract

The invention discloses a device and a method for measuring the ionization rate of water vapor molecules in air. The measuring device comprises a measuring box, a radon chamber, a pump and a high-pressure module. The measuring box is a rectangular box body, a first joint and a second joint are respectively arranged on two corresponding side walls of the box body, a panel and a bottom plate of the box body are both conductive metal plates, and a circular semiconductor detector is arranged on the panel. A first connector of the measuring box is connected with a first connector of the radon chamber, a second connector of the measuring box is connected with one end of the pump, the other end of the pump is connected with a second connector of the radon chamber, a panel of the measuring box is connected with a cathode of the high-voltage module, and a bottom plate of the measuring box is connected with an anode of the high-voltage module. During measurement, the high-voltage module is turned on, a cylindrical uniform electrostatic field is formed between the detector and the bottom plate, positively charged Po-218 is collected to the surface of the detector, the collection efficiency of the Po-218 under different voltages is obtained, the collision frequency of the Po-218 and OH<-> and the value of the composite probability of the Po-218 and OH<-> are obtained through fitting, and then the ionization rate of water vapor molecules in air is obtained through calculation.

Description

technical field

[0001] The present invention relates to a kind of nuclear radiation measuring technique, especially a kind of measuring hydroxide (OH) in the air - ) device and method for ion concentration. Background technique

[0002] Po-218 (RaA) is formed by the decay of radon and is also radioactive. After inhalation, it will cause internal exposure to the human respiratory system. Therefore, its physical and chemical properties are very important for understanding the behavior of daughter bodies in indoor air. Po-218 produced after radon decay was found to be 88% positively charged ions. It is generally believed that the main reason for the decrease in the collection efficiency of the electrostatic collection method is the positively charged Po-218 and the OH produced by ionization in the air. - The ions bound to become neutral cannot be collected on the surface of the detector, so the detector cannot detect the alpha particles produced by the decay of Po-218. Ther...

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