2017/04/23 by Y. Nakano, H. Sekiya, S. Tasaka +4
Chemistry · Physics and Astronomy · #Activated charcoal #Adsorption #Analytical Chemistry (journal) #Buffer (optical fiber) #Buffer gas #Calibration #Chemistry #Contamination #Detector #Environmental chemistry #Environmental science #Materials science #Neutrino Physics Research #Nuclear physics #Optics #Particle physics theoretical and experimental studies #Physics #Radiation Detection and Scintillator Technologies #Radiochemistry #Radon #Radon gas #Soil gas #Super-Kamiokande #hep-ex #physics.ins-det
paper · pdf · doi:10.1016/j.nima.2017.04.037
15 pages, 9 figures (accepted for publication in Nuclear Inst. and Methods in Physics Research, A)
arxiv created 2017/04/23 · openalex publication_date 2017/04/24 · arxiv updated 2017/04/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
To precisely measure radon concentrations in purified air supplied to the Super-Kamiokande detector as a buffer gas, we have developed a highly sensitive radon detector with an intrinsic background as low as 0.33±0.07 mBq/m3. In this article, we discuss the construction and calibration of this detector as well as results of its application to the measurement and monitoring of the buffer gas layer above Super-Kamiokande. In March 2013, the chilled activated charcoal system used to remove radon in the input buffer gas was upgraded. After this improvement, a dramatic reduction in the radon concentration of the supply gas down to 0.08 ± 0.07 mBq/m3. Additionally, the Rn concentration of the in-situ buffer gas has been measured 28.8±1.7 mBq/m3 using the new radon detector. Based on these measurements we have determined that the dominant source of Rn in the buffer gas arises from contamination from the Super-Kamiokande tank itself.