The excavation and construction of an area 700 meters underground for the Jiangmenneutrino observatory has been completed, and lab equipment will be installed soon. It was announced yesterday at a Shanghai Jiao Tong University conference.

The Jiangmen Underground Neutrino Observatory will be ready for experiments in 2021, and is expected to run for at least 20 years.

The research team, led by Chinese scientists with participation from 600 scientists from 17 countries and regions, is expected to determine the neutrino mass hierarchy in six years.

“Neutrinos are one of the fundamental particles which make up the universe,” said Xu Donglian, a scientist from Shanghai Jiao Tong University and a member in the program.

“The findings of the neutrino mass hierarchy will help us know more about space and the world, such as the evolution of stars and black holes and also the detailed structure of the Earth core.”

Neutrinos are among the least known particles as they interact only via weak subatomic force and gravity.

They had been believed to be weightless as photons until scientists found in 1998 that they turned from one type to another when flying, a phenomenon called “neutrino oscillation.”

Three types of neutrinos are currently known but many more discoveries await, such as the precise values of their masses, their mass hierarchy and whether they are antiparticles of each other.

In 2014, the Jiangmen neutrino observatory program was launched in Jiangmen City,south China’s Guangdong Province, to examine the remaining problems.

The huge facility is being built 700m underground to avoid interference from cosmic rays.

The space has been excavated and the basic structure built. It will host a spheroidal facility, with a diameter of 35 meters and weighing 20,000 tons.

The “ball” will be assembled with numerous components attached with super acute detectors to catch and analyze neutrinos.

By studyingneutrinos sent from the nearby nuclear plants in Yangjiang and Taishan, researchers hope to not only determine the neutrino mass hierarchy, but also measure neutrino oscillations more accurately.

The team will also conduct research in other cutting-edge areas, such as supernova neutrinos, atmospheric neutrinos, solar neutrinos, Earth neutrinos, sterile neutrinos, nuclear decay and detection of dark matter.

“After experiments start in Jiangmen, we will be able to find answers to many key scientific problems, such as the neutrino mass hierarchy and the supernova burst mechanism,” said Wang Yifang.

He is the director of the Jiangmen program and also director of the Institute of High Energy Physics of the Chinese Academy of Sciences.

“It will make great contributions to the understanding of micro particle physic laws, cosmology, astrophysics and geophysics,” he said.

Liu Jianglai, another scientist from Shanghai Jiao Tong University and a member in the program, said the United States and Japan were also doing similar research via different approaches, but Jiangmen had the advantage in research of low-energy neutrinos and is set to be the quickest. “We plan to solve the mass hierarchy problem within six years,” he said.