China completes giant sphere to hunt for ghost seeds

China is one step closer to measuring the mysterious neutrino particle after installing a giant spherical detector underground in Guangdong province.

The sphere is about 35 meters in diameter and is the central part of the Jiangmen Underground Neutrino Observatory (Juno) , a project in Jiangmen City, Guangdong Province. The sphere will contain about 20,000 tons of scintillators and be suspended in 35,000 tons of pure water at a depth of 700 meters underground to measure the masses of different types of neutrinos produced by two nearby nuclear power plants, MSN reported on October 13.

The spherical detector at the Jiangmen Underground Neutrino Observatory (Juno). (Photo: Xinhua).

Nicknamed "ghost particles ," neutrinos are elementary particles that are difficult to detect because they have no electric charge , very little mass, and travel at nearly the speed of light. Although most particles pass through a liquid without leaving a trace, some interact with the liquid, creating two flashes of light that can be detected by thousands of photodetectors.

According to CCTV, the sphere has been installed and engineers are currently assembling its outer metal shell and optical tubes. The installation is expected to be completed by the end of November and the facility will begin collecting data in August next year. Previously, data collection was scheduled for 2023.

Construction of the laboratory began in 2015 but was delayed due to groundwater issues. The international project involves 750 researchers from 74 institutes in 17 countries and regions, nearly 300 of whom are 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 did not collaborate on the Juno project. Juno is expected to be the first of a new generation of neutrino detectors operating around the world.

Both the Deep Underground Neutrino Experiment in the US and the Hyper-Kamiokande Observatory in Japan are scheduled to be completed and operational around 2027-2028. According to Wang Yifang, director of the Institute of High Energy Physics (IHEP) of the Chinese Academy of Sciences, the team has developed many technologies to upgrade Juno, including the world's most efficient light-detecting optical tube. All results obtained during Juno's construction and future operations will be published by the international collaboration. Juno will take 5-6 years to collect a total of 100,000 signals to resolve the question of neutrino mass.