The development of $$^{222}\hbox {Rn}$$ detectors for JUNO prototype

Background JUNO (The Jiangmen Underground Neutrino Observatory) is a multipurpose neutrino experiment, and it has very strict requirements for the detector. According to the MC simulation for JUNO experiment requirements, the Rn concentration in the water of the veto detector should be less than 0.2Bq/m\(^{3}\). In order to measure such low Rn concentration, two kinds of high-sensitivity Rn measurement systems have been developed.