Construction site of Japan's upgraded neutrino observatory unveiled to media

TOKYO, Oct 31 (NHK) - Reporters have been invited to get their first look at the ongoing construction of the third-generation Hyper-Kamiokande detector in central Japan. The underground detector is designed to observe elementary particles called neutrinos falling from space.

The detector's predecessors, Kamiokande and Super-Kamiokande, have led to Japanese scientists winning two Nobel Prizes in Physics. One of them was the late 2002 laureate Koshiba Masatoshi, who was the first researcher to observe neutrinos at the Kamiokande built in Hida City, Gifu Prefecture.

Construction of the Hyper-Kamiokande began three years ago at a site 600 meters underground. It is expected to enable researchers to detect about eight times as many neutrinos than the Super-Kamiokande.

The University of Tokyo's Institute for Cosmic Ray Research, which operates the detectors, on Sunday allowed the media to enter a cavern under construction.

A giant water tank will be placed inside the cavity. Its dome section has a diameter of 69 meters and a height of 21 meters. Some 40,000 photodetectors will be installed inside the water tank.

Operation of the Hyper-Kamiokande is scheduled to begin in 2027.

Researchers hope that the upgraded facility will result in new discoveries of neutrinos, and enhance research on the evolution of the universe.