Engineers are scheduled to start building the Deep Underground Neutrino Experiment on Monday, a U.S.-led project a mile beneath Lead, South Dakota, that physicists hope will help explain why the universe is made of matter rather than antimatter.
The experiment, known as DUNE, will place four detectors in caverns cut from the rock of the former Homestake gold mine. Assembly should take nearly three years, and filling the detectors with liquid argon will take about one more.
The hardware is massive. The detectors will use more than 4,000 metric tons of steel, rise as high as five stories and together hold 70,000 metric tons of liquid argon chilled to minus 200 degrees Celsius. Prof. David Newbold, a DUNE spokesperson with the UK's Science and Technology Facilities Council, likened the job to building a ship underground.
How the experiment works
Fermilab, the government particle physics lab near Chicago, will fire an intense neutrino beam through 800 miles of Earth's crust and mantle toward the mine. Most of those particles will pass straight through, but a few will hit argon atoms, each leaving a flash of light and a pulse of electric charge for researchers to analyze.
Those signals could address a long-standing puzzle. By hunting for slight differences between neutrinos and antineutrinos, their antimatter counterparts, the team hopes to learn why matter exists in the first place.
Why neutrinos are so elusive
Neutrinos carry no charge and barely interact with anything, so about a trillion slip through a human body every second unnoticed. Only photons outnumber them in the universe.
Neutrinos do not make sense yet and they could open a door to new physics.
Dr. Kate Shaw, experimental particle physicist, University of Sussex
They also change identity. The particles come in three varieties with tiny but different masses, and they switch from one to another as they travel, a process known as oscillation. Learning which variety is heaviest and which is lightest could reveal new fundamental forces of nature.
DUNE will also catch neutrinos from the sun and distant supernovae, which could yield new information on dying stars and the birth of black holes. This month, the Nobel Prize in Physics honored Belgian researcher Francis Halzen, who used a cubic kilometer of Antarctica to detect high-energy neutrinos from deep space.
Partners and a mine's history
The United Kingdom is the project's largest international partner. It is making core detector components, the computing needed to reconstruct events inside the detectors, and the graphite target that will generate neutrinos at Fermilab.
Lead already holds a place in neutrino history. In the 1960s, physicist Ray Davis built a detector in the mine from a 100,000-gallon tank of dry-cleaning fluid, and it became the first to record neutrinos from the sun. The mine shut down in 2001 and became the Sanford Underground Research Facility, also home to the LZ experiment, which announced a possible first detection of dark matter last month.
We’ve gone from mining the Earth to helping scientists explore the universe
Robin Lucero, Lead city administrator
City administrator Robin Lucero, whose family has lived in the area for generations, said the science is bringing new people and opportunities to local businesses and young residents.
