World's deepest, largest underground lab opened

A 2.4-kilometer-deep physics laboratory in Southwest China's Sichuan province became operational on Thursday, making it the deepest and largest underground lab in the world.

Scientists believe the laboratory provides a "clean" space for them to pursue the invisible substance known as dark matter. They said the extreme depth helps block most cosmic rays that mess with observations.

The Deep Underground and Ultra-low Radiation Background Facility for Frontier Physics Experiments (DURF) is located beneath Jinping Mountain in Sichuan's Liangshan Yi autonomous prefecture.

The DURF, with a total area of 330,000 cubic meters, is the second phase of the giant China Jinping Underground Laboratory. It started construction in December 2020 and was jointly built by Tsinghua University and Yalong River Hydropower Development Company.

Thanks to its location, the DURF is exposed to only a tiny flux of cosmic rays that are one hundred millionth that on the Earth's surface. It boasts advantages including extremely low environmental radiation, extremely low radon concentration and an ultra-clean space, which will boost dark matter detection, said Yue Qian, a researcher at Tsinghua University's Department of Engineering Physics.

The DURF has sufficient electricity and water supply, convenient transportation and adequate infrastructure, the researcher said.

Scientists infer that visible matter accounts for only about 5 percent of the universe, while some 95 percent of the universe is made up of dark matter and dark energy.

The first 10 teams from Chinese universities and research institutions, such as Tsinghua University and Shanghai Jiao Tong University, have been stationed in the DURF to carry out scientific experiments.

The research fields of those teams cover a variety of disciplines such as dark matter detection, neutrino research, nuclear astrophysics and weak force measurement.

The DURF will become a world-class interdisciplinary deep underground research center, Yue said.

China Daily - Xinhua