South Dakota crews excavate 800,000 tons of rock to build world’s largest neutrino detector

Solving physics puzzles a mile underground

In context: Neutrinos are among the most elusive elementary particles ever discovered. They have a very small mass, they rarely interact with ordinary matter, but they could be the key to answering some of the most fundamental questions in particle physics.

Researchers leading the Deep Underground Neutrino Experiment (DUNE) at the Long-Baseline Neutrino Facility (LBNF) have completed the first phase of a major science project led by US facilities. Engineers and construction workers removed 800,000 tons of rock from the Sanford Underground Research Facility in Lead, South Dakota, making way for one of the most advanced research projects into neutrinos and their elusive nature.

The underground excavation was completed in August, and the US Department of Energy is now publishing plans for how researchers will use the new cave system, which is a mile underground. This facility will house several large, seven-story neutrino detectors and their essential science equipment, which will bring the project to life in the coming years.

LBNF-DUNE is an international collaboration that aims to “solve the neutrino mystery,” according to Fermilab researchers. The US works with international partners from 35 countries, sending a “stream” of neutrinos from the Department of Energy’s Fermi National Accelerator Laboratory in Illinois to the remote detector in South Dakota.

The neutrinos will pass through natural rock and stone as they travel from the facility in Illinois to the underground detectors in South Dakota. Each detector will be filled with 17,000 tons of liquid argon, which will maximize the chance of detecting neutrino interactions while protecting the detectors from cosmic neutrinos.

The excavation process took three years, and 800,000 tons of rock were moved to the surface for storage in a closed mine. The next step involves installing the long detector in the newly excavated underground system, and work is expected to begin in 2028. After that, the LBNF team will -DUNE the “closer” detector at Fermilab to complete the experiment.

The Department of Energy has described the LBNF-DUNE project as the beginning of a new era in understanding neutrinos and their role in the standard model of particle physics. Despite being theorized 100 years ago, neutrinos still puzzle scientists, especially because they are supposed, according to the General Model, to be massless.

However, neutrinos are not completely damageless like photons. Although we have not measured the exact mass, scientists believe that neutrinos may be the most important in solving the puzzle of Standard Model particles, which may explain the non- balance between matter and antimatter that shaped our universe after the Big Bang. The LBNF-DUNE project aims to solve this crucial piece of our scientific understanding.