China Moves Closer to Detecting Mysterious Neutrinos with the Installation of a Giant Underground Spherical Detector in Guangdong Province
The spherical detector, with a diameter of approximately 35 meters, is the centerpiece of the Jiangmen Underground Neutrino Observatory (Juno) project located in Jiangmen City, Guangdong Province. This sphere will contain around 20,000 tons of scintillating material, suspended in 35,000 tons of pure water at a depth of 700 meters underground, to measure the mass of various types of neutrinos generated by two nearby nuclear power plants, as reported by MSN on October 13.
Spherical detector at the Jiangmen Underground Neutrino Observatory (Juno). (Photo: Xinhua).
Known as “ghost particles”, neutrinos are fundamental particles that are extremely difficult to detect due to their lack of electric charge, very small mass, and their travel at speeds nearly equal to that of light. While almost all particles pass through liquid environments without leaving traces, a few types interact with the liquid, producing two flashes of light that thousands of photomultiplier tubes can detect.
According to CCTV, the spherical detector has been installed, and engineers are currently assembling its outer metal shell along with the photomultiplier tubes. The installation process is expected to be completed by the end of November, with data collection starting in August of next year. Previously, data collection was scheduled for 2023.
Construction of the laboratory began in 2015 but faced delays due to groundwater issues. This international project involves a team of 750 researchers from 74 institutions across 17 countries and territories, with nearly 300 experts from Europe, including Italy, Germany, and France.
Juno is a follow-up to the Daya Bay Reactor Neutrino Experiment, which operated from 2003 to 2020 near Shenzhen, Guangdong Province. American scientists participated in the Daya Bay project but are not collaborating on the Juno project. Juno is expected to be the first operating machine among the new generation of neutrino detectors worldwide.
Both the Deep Underground Neutrino Experiment in the United States and the Hyper-Kamiokande observatory in Japan are scheduled to be inaugurated and operational around 2027-2028. According to Wang Yifang, the director of the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences, the expert team has developed many technologies to upgrade Juno, including the most efficient photomultiplier tubes in the world. All results obtained during the construction and future operation of Juno will be published by the international collaboration team. Juno is expected to take 5-6 years to collect a total of 100,000 signals to address the question of neutrino mass.
