Construction starts on DUNE, the giant underground neutrino hunt

A beam of neutrinos and antineutrinos, generated at Fermilab near Chicago, will travel 1,300 kilometres to the underground detectors in South Dakota. A smaller detector at Fermilab will measure the particles close to their source, so scientists can compare what arrives at each end. By studying how the particles change in transit, researchers hope to learn:

• why the Universe contains so much more matter than antimatter
• how neutrinos behave and transform as they travel
• what neutrinos can reveal about exploding stars, including supernovae

The deep underground location shields the detectors from cosmic rays and other background radiation. CERN is leading the construction of two cryostats at SURF, each built from thousands of steel support beams transported underground, and each holding around 17,000 tonnes of liquid argon. The Illinois and South Dakota facilities together form the Long-Baseline Neutrino Facility (LBNF), the infrastructure backbone for DUNE.

Who is powering the beam?

DUNE's neutrino beam depends on a major Fermilab accelerator upgrade called PIP-II (the Proton Improvement Plan-II). Daresbury Laboratory is delivering three superconducting accelerator modules and components for a fourth, helping accelerate the protons that generate the beam. Rutherford Appleton Laboratory researchers have contributed specialist expertise to the target system: when the proton beam strikes the target, it produces the neutrinos that head toward South Dakota.

RAL also plays the leading international role in DUNE's data-acquisition system — the hardware and software that must capture and record the enormous data volumes the detectors will produce.

What did the scientists say?

Professor Gary Barker of the University of Warwick, Principal Investigator for DUNE-UK, said: "The UK neutrino community is making a major contribution to DUNE, providing unique expertise to the international project across precision engineering, advanced software and physics analysis deliverables. We are well advanced to completing our production runs, and this milestone is a key step towards our goal of having detectors installed underground and taking physics data."

Professor Dave Newbold, Executive Director of National Laboratories at STFC and recently elected co-spokesperson of the DUNE collaboration, said: "The DUNE experiment has the potential to change our understanding of the universe." He added that the UK contributions have come "not only from academics and students, but also from engineers and technicians in our national laboratories and in British industry."

CERN director general Mark Thomson said: "Collaboration is in CERN's DNA, and our contribution to DUNE is a brilliant example of cross-organisational partnership. After years of planning and careful coordination, I am thrilled to see that we are ready to start installation."

When will data start flowing?

The underground space is planned for completion by 2029, with the detector apparatus installed by 2030. From that date, an 1,800-strong worldwide team will begin observing particles from the Sun and outer space. The terrestrial neutrino beam from Fermilab's PIP-II upgrade is expected to reach the South Dakota detectors by 2031, launching DUNE's long-term scientific programme.

Professor Ryan Nichol of University College London said: "Once they are built, the DUNE detectors will be some of the most precise scientific instruments ever constructed. They will be capable of detecting particles from stars exploding on the other side of our galaxy, and of using quantum physics to measure the difference in mass between two of the lightest particles in the universe."

A mile of rock, 17,000 tonnes of cold argon and 137 British-built wire panels now stand between physicists and some of nature's oldest questions.