Assembly and installation of the main structure for the central detector of the Jiangmen Underground Neutrino Observatory (JUNO) were successfully completed on June 24. The main structure consists of a spherical stainless steel shell 41 meters in diameter. It sits inside a water pool approximately 44 meters deep that is located 700 meters underground. The structure will support an acrylic vessel 35.4 meters in diameter that is filled with liquid scintillators weighing 20,000 tons. Key components, including 20,000 20-inch photomultiplier tubes, 25,000 3-inch photomultiplier tubes, front-end electronics, cables, anti-geomagnetic field coils, and many others, are also supported by the main structure.

The completion of the main structure also means beginning on-site installation of the acrylic vessel, which weighs more than 600 tons and has a wall thickness of 120 mm. The vessel’s production and installation will be unprecedented. When completed, it will be the world's largest single acrylic structure. Completing its installation in a short period will be a challenging task for the collaboration and will require developing nontraditional approaches.

JUNO is a large scientific facility jointly built by the Chinese Academy of Sciences and Guangdong Province. It is scheduled to begin operation in 2023. Its main scientific goals are the determination of neutrino mass ordering and accurate measurement of neutrino mixing parameters. It will also play a role in a number of other cutting-edge scientific research projects.

The completion of the main structure also means beginning on-site installation of the acrylic vessel, which weighs more than 600 tons and has a wall thickness of 120 mm. The vessel’s production and installation will be unprecedented. When completed, it will be the world's largest single acrylic structure. Completing its installation in a short period will be a challenging task for the collaboration and will require developing nontraditional approaches.

JUNO is a large scientific facility jointly built by the Chinese Academy of Sciences and Guangdong Province. It is scheduled to begin operation in 2023. Its main scientific goals are the determination of neutrino mass ordering and accurate measurement of neutrino mixing parameters. It will also play a role in a number of other cutting-edge scientific research projects.