Probing the Mysteries of Neutrinos a Mile Underground
Rohit Raut, James Wilhelmi, Tyler Stokes, Frank Lopez, and Karsten Heeger in the DUNE clean room assembly area in a Wright Lab high bay.
4,850 feet beneath the surface of the Earth in a former gold mine, scientists and engineers are building one of the most ambitious physics experiments ever conceived: the Deep Underground Neutrino Experiment (DUNE).
Neutrinos are the most abundant matter particles in the Universe. They were produced in the early Universe, are emitted from the inside of stars and nuclear decays, and continue to stream at essentially the speed of light through the Universe.
At Yale’s Wright Lab, the group of Karsten Heeger, Eugene Higgins Professor of Physics and Director of Wright Lab, is building critical components for DUNE’s neutrino detectors in order to study the behavior of neutrinos and their antiparticles, catch neutrinos from the atmosphere and the Sun, and probe if neutrinos might be able to explain the predominance of matter in the Universe.
DUNE is an international experiment designed to detect neutrinos produced on Earth and in astrophysical sources and measure a phenomenon known as neutrino oscillation. The U.S. Department of Energy’s Fermi National Accelerator Laboratory (Fermilab) will send a high-energy neutrino beam over a distance of 1300 km through the Earth’s crust from Chicago, Illinois to the Sanford Underground Research Facility (SURF) in South Dakota to enable the precision studies of neutrinos as they travel through the Earth.
DUNE’s primary science goals are to investigate whether neutrinos and antineutrinos behave the same and understand the ordering of the neutrino mass states. DUNE will also look for neutrinos emerging from an exploding star, perhaps witnessing the birth of a neutron star or a black hole and detect neutrinos produced in the atmosphere.
Fermilab is the host laboratory for DUNE, in partnership with funding agencies and more than 1,400 scientists and engineers from all over the globe, including the Heeger Group at Wright Lab.
Large Science Deep Underground
Tyler Stokes, Rohit Raut, and James Wilhelmi in front of a signed beam, pointing at Raut’s signature.
Massive 17 kiloton Liquid Argon (LAr) Time Projection Chamber (TPC) neutrino detectors will be constructed in the DUNE caverns 4850 feet underground at SURF to image neutrino interactions and reconstruct their tracks as they enter the detectors. Earlier this year, DUNE was named the Project of the Year by the Underground Construction Association for the excavation and construction of the underground facilities.
On May 7, DUNE celebrated the beginning of cryostat assembly at SURF with a special ceremony and a signing of the first beam to go down into the caverns. Collaboration members were also invited to sign a beam during a collaboration meeting at the end of May to celebrate this milestone for DUNE.
Members of the Heeger group work on the DUNE CRP assembly in a clean room setup at Wright Lab.
Yale is one of two US assembly sites for DUNE’s charge readout planes (CRPs), critical components of the far detectors. The CRPs are the basic readout components of the detector modules; the mechanism that translates the data obtained by the DUNE experiment into machine-readable output.
At Yale, large circuit boards, their composite support structure, and electronics are integrated to form the Charge Readout Planes. Following cryogenic testing in liquid nitrogen, the CRPs are delivered to SURF for the installation underground.
The CRP assembly effort at Wright Lab is a collaboration between Yale University, CERN, the Department of Energy’s Brookhaven National Laboratory (BNL), and the University of Indiana.
Tyler Stokes, Wright Lab postdoctoral associate, the scientific lead for the CRP assembly and testing at Yale and the Young DUNE Spokesperson Liaison, explained that a critical step is the “cold box” test at Yale.
Stokes said, “Once the CRPs leave Yale, they will not be cryogenically tested again before they are installed a mile underground, and the complete detector will be turned on. So the testing phase at Yale is critical.”
Following installation, the Heeger group will be involved in the commissioning of the detectors and first data-taking with DUNE. DUNE is set to begin taking science data in 2029, with the first beam of neutrinos arriving at SURF in 2031.
Impressions from Underground
Rohit Raut, Karsten Heeger, Tyler Stokes, and James Wilhelmi in the DUNE cavern.
During a recent DUNE collaboration meeting, the Heeger group visited the DUNE caverns at the 4,850-foot level.
Heeger, who has worked in several major underground research facilities around the world, said, “Seeing the DUNE underground facilities was truly impressive and their scale is awe-inspiring.”
Stokes reflected, “I am in my eighth year working on the DUNE experiment, so I have followed the excavation and construction of the DUNE caverns from afar since that work began. Seeing the future home of DUNE in person puts many years of work into perspective.”
Stokes continued, “Our DUNE CRP assembly site here at Wright Lab occupies a large portion of the high bay, yet a single DUNE Far Detector module is more than twice that size in volume and located nearly a mile underground.”
Wright Lab graduate student Rohit Raut added, “Standing in the cavern that will one day house the DUNE Far Detector was one of the most memorable experiences of my Ph.D. so far. For years, the experiment had existed in my mind through simulations, engineering drawings, meetings, and the Charge Readout Planes we assemble at Yale’s Wright Laboratory. Descending nearly a mile underground transformed that abstract picture into something tangible.”
Raut continued, “What struck me most was not only the immense scale of the space, far greater than any photograph can convey, but also the realization that this cavern will soon become home to one of the most ambitious scientific instruments ever built.¨
Heeger said, ¨With the outstanding facilities at Wright Lab, we have an opportunity to build critical detector components for one of the world’s largest underground neutrino experiments. This is a unique opportunity for Wright Lab to play a critical role in this international collaboration and to help build the U.S. DUNE experiment. Students and young researchers gain hands-on technical and scientific experience and work with colleagues from near and far.¨
Raut concluded, “As a member of the team producing Charge Readout Planes for the detector, seeing its future home gave me a new appreciation for the scope of what thousands of scientists and engineers are working together to achieve. Knowing that I will return to South Dakota to help install and commission components that I am helping build today connected the workbench, the detector, and the scientific goals of DUNE into a single vision. Walking through that cavern, I felt I was seeing more than a construction site. I was seeing the future of an experiment that will shape the next chapter of my research career, and I felt privileged to play a part in bringing it to life.”
The Yale DUNE team currently includes Heeger, Stokes, Raut, and engineer James Wilhelmi. The CRP assembly and testing efforts are supported by Wright Lab’s expert technical staff, including research technicians Tom Hurteau, Frank Lopez, and Craig Miller. For more detailed information on the Heeger group’s DUNE efforts, see the DUNE Projects webpage.