Background The Jiangmen Underground Neutrino Observatory(JUNO),a 20-kton multipurpose underground liquid scintillator detector,was proposed with the determination of the neutrino mass hierarchy as a primary physics go...Background The Jiangmen Underground Neutrino Observatory(JUNO),a 20-kton multipurpose underground liquid scintillator detector,was proposed with the determination of the neutrino mass hierarchy as a primary physics goal.To veto the cosmogenic background and shield the central detector from the environmental radioactivity,a multi-veto system,which consists of a water Cherenkov detector and a top tracker detector,is required.In order to keep the water quality good and remove the radon from water,an ultrapure water system,a radon removal system and radon concentration measurement system have been designed.Method The JUNO ultrapure water system was designed on the basis of the water system of the Daya Bay experiment.By installing the degassing membrane devices on the water system of JUNO prototype and Daya Bay experiment which can remove radon from water,the radon removal efficiency has been measured at the conditions of different gas–liquid phase pressures and different gas concentrations in water using the radon measurement system.Result Loading carbon dioxide into the water and increasing the inlet water pressure could help to improve the radon removal efficiency of the degassing membrane devices,and the radon concentration in water can be reduced to∼0.1 Bq/m^(3).Conclusion A reliable ultrapure water production and circulation system has been designed to keep the water quality good and to reduce the radon concentration in water for JUNO water Cherenkov detector.The radon concentration in water can satisfy the requirement of JUNO by using the Liqui-Cel degassing membrane devices.展开更多
基金This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA10010300).
文摘Background The Jiangmen Underground Neutrino Observatory(JUNO),a 20-kton multipurpose underground liquid scintillator detector,was proposed with the determination of the neutrino mass hierarchy as a primary physics goal.To veto the cosmogenic background and shield the central detector from the environmental radioactivity,a multi-veto system,which consists of a water Cherenkov detector and a top tracker detector,is required.In order to keep the water quality good and remove the radon from water,an ultrapure water system,a radon removal system and radon concentration measurement system have been designed.Method The JUNO ultrapure water system was designed on the basis of the water system of the Daya Bay experiment.By installing the degassing membrane devices on the water system of JUNO prototype and Daya Bay experiment which can remove radon from water,the radon removal efficiency has been measured at the conditions of different gas–liquid phase pressures and different gas concentrations in water using the radon measurement system.Result Loading carbon dioxide into the water and increasing the inlet water pressure could help to improve the radon removal efficiency of the degassing membrane devices,and the radon concentration in water can be reduced to∼0.1 Bq/m^(3).Conclusion A reliable ultrapure water production and circulation system has been designed to keep the water quality good and to reduce the radon concentration in water for JUNO water Cherenkov detector.The radon concentration in water can satisfy the requirement of JUNO by using the Liqui-Cel degassing membrane devices.
