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arXiv · 2403.12414

Development of low-radon ultra-pure water for the Jiangmen Underground Neutrino Observatory

T. Y. Guan·Y. P. Zhang·B. Wang·C. Guo·J. C. Liu·Q. Tang·C. G. Yang·C. Li
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Abstract

The Jiangmen Underground Neutrino Observatory(JUNO) is a state-of-the-art liquid scintillator-based neutrino physics experiment under construction in South China. To reduce the background from external radioactivities, a water Cherenkov detector composed of 35~kton ultra-pure water and 2,400 20-inch photomultiplier tubes is developed. Even after specialized treatment, ultra-pure water still contains trace levels of radioactive elements that can contribute to the detector background. Among which $^{222}$Rn is particularly significant. To address this, an online radon removal system based on the JUNO prototype has been developed. By integrating micro-bubble generators to enhance degasser's radon removal efficiency, the radon concentration in water can be reduced to 1~mBq/m$^{3}$ level, meeting the stringent requirements of JUNO. Additionally, a highly sensitive online radon concentration measurement system capable of detecting concentrations $\sim$1~mBq/m$^3$ has been developed to monitor the radon concentration in water. In this paper, the details regarding both systems will be presented.

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T. Y. Guan, Y. P. Zhang, B. Wang, C. Guo, J. C. Liu, Q. Tang, C. G. Yang, C. Li. 2024-03-19. Development of low-radon ultra-pure water for the Jiangmen Underground Neutrino Observatory. https://arxiv.org/abs/2403.12414

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