The excavation of the main cavern for the Hyper-Kamiokande neutrino detector has been completed, marking a key milestone in the construction of one of the world’s largest underground physics experiments.
The cavern, located in Hida, Gifu Prefecture, is designed to house a giant water tank that will form the core of the next-generation detector. According to the Jagiellonian University, the space consists of a dome-shaped ceiling about 69 meters in diameter and 21 meters high, connected to a cylindrical section 73 meters in height.
The next stage of the project will transform the cavern into a reservoir for “ultra-pure” water. Installation of detector components is scheduled for completion in 2027, with operations expected to begin in 2028.
Hyper-Kamiokande’s scientific goals include precise measurements of neutrino properties and searches for proton decay, which may shed light on the fundamental structure of matter and test Grand Unified Theories.
Polish researchers are part of the international effort, which involves nearly 630 scientists from 22 countries.
Nine Polish institutions are represented: the National Centre for Nuclear Research (the Polish consortium coordinator), the Institute of Nuclear Physics of the Polish Academy of Sciences, the University of Silesia, the Warsaw University of Technology, the University of Warsaw, the University of Wrocław, AGH University of Science and Technology, the Jagiellonian University, and the Nicolaus Copernicus Astronomical Centre.
Hyper-Kamiokande will consist of a water tank with a volume more than eight times larger than its predecessor, the Super-Kamiokande detector.
The facility will be equipped with over 20,000 newly developed photodetectors.
On its website, the University of Silesia describes how the detector will operate: “The advantage of this type of detector is the relatively simple operating principle: neutrinos are detected in a large volume of extremely pure water, surrounded by light detectors called photomultipliers. When a neutrino interacts with water, it can create charged particles that travel faster than the speed of light in water.
“This results in the emission of Cherenkov radiation, which has the shape of a cone. This phenomenon can be compared to the shock wave that occurs when an object exceeds the speed of sound in air, except in this case, it concerns light in water.
“Photomultipliers placed on the walls of the tank detect the characteristic blue radiation in the form of light rings. Based on these rings, it is possible to reconstruct the parameters of the particle that generated the radiation, as well as the neutrino itself.”
The Hyper-Kamiokande project is led by the University of Tokyo and Japan’s High Energy Accelerator Research Organization (KEK). (PAP)
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