Underground Excavation for DUNE Detectors Completed in South Dakota; Neutrino Detection Technology to Solve Key Mystery in Physics

Neutrinos are among the most abundant particles that make up the universe, yet they are the least understood. Since they do not have any charge, these subatomic particles interact only through gravity and the weak subatomic force.

These tiny bits of materials are also called quantum chameleons, meaning neutrinos can change their identity, with one type transforming into another before returning to its original form. Studying their behavior can help experts understand why our observable universe looks like it does.

DUNE Experiment

To better understand the behavior of neutrinos, experts working at Fermi National Accelerator Laboratory (Fermilab) decided to build gigantic particle detectors. They are much closer to achieving their goals with the completion of underground excavation works.

Crews started hauling colossal caverns seven years ago, digging 800,000 tons of rock from a former gold mine near Lead, South Dakota. They were able to unearth three underground tunnels that measure 500 feet (152 meters) long, comparable to the size of eight soccer fields. The caverns are located a mile below the surface and are tall enough to hold a seven-story building.

The Project DUNE (Deep Underground Neutrino Experiment) is estimated to cost at least $3 billion. It will release a beam of neutrinos from the Fermilab campus 800 miles (1,300 kilometers) to a detector complex housed at the Sanford Underground Research Facility (SURF) in South Dakota.

When fully completed, the facility will consist of four large detectors, each containing 17,500 tons of liquid argon. This substance will detect stoedetecteutrinos that pass through them.

At its normal state, argon is a gas, making up about 1% of the Earth's atmosphere. However, it can become a transparent liquid when extracted, purified, and cooled to -300 degrees Fahrenheit (-186 degrees Celsius). When neutrinos pass through liquid argon, a small fraction interact and generate electric signals and a fleeting flash of light. This information can determine the nature of the interaction and identify whether the neutrino has changed its identity as it travels from one facility to the other.

After the installation of the support structure, scientists will start installing the detectors themselves. The first detectors are expected to begin collecting data in 2028, with other detectors coming online in the coming years.

What Will DUNE Try To Solve?

DUNE will carry out different measurements, primarily the transformation properties of neutrinos and their antimatter analogs. When different forms of matter and antimatter combine, they can release huge amounts of energy. However, just like matter neutrinos, antimatter neutrinos rarely interact as well.

Neutrinos could be classified into electrons, muons, and tau particles based on the particles created during interactions. Among these three types, muons and tau particles are essentially heavy and unstable electrons.

Upon completing the underground facility, Fermilab will generate a beam of nearly pure muon neutrinos and use the far detector to observe their transformation. This will be repeated with the use of antimatter muon neutrinos.