Located more than 2,000 feet below the ground, China is close to completing its state-of-the-art neutrino detector.
The Jiangmen Underground Neutrino Observatory (JUNO) is a massive sphere filled with 20,000 tons of liquid scintillator that will produce flashes of light when neutrinos collide with matter. The collisions will be detected by a network of 43,200 photomultiplier tubes. Neutrinos are the most mysterious particles in the universe, often called the ghost particles.
The elusive neutrino
The neutrino is the smallest non-zero particle in the universe, roughly a million times smaller than an electron. It may seem counter-intuitive to build a massive detector more than 2,000 feet underground just to detect the tiniest particle in the known universe, but it is the only way scientists would ever have the chance to spot them.
“The solution for how we measure these neutrinos is to build very, very big detectors,” said Andre de Gouvea, a theoretical physicist at Northwestern University who is not involved with the project.
Neutrinos are very different from protons, electrons and neutrons, not only because of their size, but also because of their charge. Protons carry a positive charge, electrons a negative one, and neutrons a neutral charge. However, a neutrino produces no charge, making it able to pass through most material undetected, hence the name ghost particle.
Neutrinos also have virtually no mass, meaning that on the rare occasions they can be detected, they are still difficult to spot. They are the least understood particles in the universe and have been around since the Big Bang.
“It’s the least understood particle in our world,” said Cao Jun, who will help manage JUNO. “That’s why we need to study it.”
China’s neutrino detector
🇨🇳CHINA BUILDS A GIANT NEUTRINO SNIFFER TO HUNT GHOST PARTICLES
Deep beneath a granite hill, China’s Jiangmen Underground Neutrino Observatory (JUNO) is gearing up to chase neutrinos—those sneaky “ghost particles” that’ve been zooming around since the Big Bang.
Built 2,297… pic.twitter.com/eKvHT2TILM
— Mario Nawfal (@MarioNawfal) December 18, 2024
China’s $300 million project is set to go live next year. According to de Gouvea, the new detector will push the boundaries of universal understanding and neutrino-detecting technology.
“If they can pull that off, it would be amazing,” said de Gouvea.
The machine will be focused on the anti-neutrinos produced by nuclear reactors about 30 miles away from the JUNO site. When they collide with the detector scientists will be able to study the signals emitted.
“By studying neutrinos, we can understand why the universe has become what it is today, and what will be the future of the universe,” said Wang Yifang.
Other nations are working on neutrino detectors similar to China’s JUNO project. Japan’s Hyper-Kamiokande is set to go online in 2027 barring any disruptions, and the United States Deep Underground Neutrino Experiment (DUNE) should be operational by 2031.