Determination of ²²²Rn by Electrostatic Collection α-spectroscopy in the Environment of High ²²⁰Rn and Low ²²²Rn

The trace ²²²Rn concentration in the ²²⁰Rn source intended to be used in the PandaX detector of CJPL (China Jinping Underground Laboratory) was measured, and a method for measuring the concentration of ²²⁰Rn and ²²²Rn under the environment of high ²²⁰Rn and low ²²²Rn was established. The phenomenon of hat the measured concentration of ²²⁰Rn in the high-purity ²²⁰Rn source by electrostatic collection a-spectroscopy is about 2% of the corresponding ²²⁰Rn. concentration count was explained by theoretical explanation and experimental verification. The upper limit of the activity ratio of ²²²Rn/²²⁰Rn of the ²²⁰Rn source intended for PandaX detector was 6.2 × 10^-5 measured by the combined measurement method of time delayed pipeline and electrostatic collection alpha spectrometer. (authors)