By rosebell
Being located 600m beneath ground near the city of Hida in Gifu Prefecture, the cavern’s digging process has been completed.
Hyper-Kamiokande (Hyper-K) is an international scientific project co-ordinated by the University of Tokyo and the High Energy Accelerator Research Organisation (KEK) and involves 640 scientists from 22 countries.
Including a gigantic water tank with a volume 8.4 times greater than its predecessor, Super-Kamiokande, the Hyper-Kamiokande is a next-generation detector and equipped with over 20,000 photomultiplier tubes.
Progressing understanding of the Grand Unified Theory and the evolutionary history of the universe by investigating phenomena such as proton decay, CP violation (the asymmetry between neutrinos and antineutrinos), and observing neutrinos from supernova explosions, are the intentions of this project.
The date of commencing excavation of the main cavern was November 2022, following the completion of the approach and access tunnels. While in October 2023 the main dome, 69m in diameter and 21m in height, was completed, boring of the vertical cavern for the main detector has been ongoing since then.
Currently work is undergoing on converting the main chamber into a giant water tank capable of holding 260,000m3 of ultra-pure water. It will be fitted with approximately 20,000 newly developed photosensors and around 1,000 multi-photosensor modules designed to detect the faint light produced by neutrino interactions.
The scheduled date for starting construction of the two-layer structure of the detector is next year, followed by the installation of photomultiplier tubes and other components.
It is expected that all internal detector components be installed by 2027, after which the tank is due to be filled with ultra-pure water, whereas Hyper-K is due to begin operations in 2028.
During a tour by representatives from the University of Tokyo, Japan’s Ministry of Education, Culture, Sports, Science and Technology (MEXT), Gifu Prefecture, and construction-related companies in June, University of Tokyo president Teruo Fujii said: “Over the next 20 years, Hyper-Kamiokande would become a hub for international collaborative research, attracting scientists from around the world.”
According to Director of MEXT’s Research Promotion Bureau, Mizue Shiomi: “Deep respect for the achievement of creating this unprecedentedly large cavern, made possible by Japan’s outstanding excavation technology and the collective wisdom of world-leading researchers.”
