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.