A special groundbreaking was held today (July 21) deep underground in South Dakota. Scientists, engineers and guests turned the first shovelfuls of the 800,000 tons of rock that will be excavated to build the Long Baseline Neutrino Facility (LBNF) at the Sanford Underground Research Facility. The cavern will house a giant detector for the Deep Underground Neutrino Experiment (DUNE).
The goal of DUNE is to better understand neutrinos and their role in the evolution of the universe, including why our universe is made of matter and not antimatter. DUNE will also be able to detect neutrinos from deep space, emitted by supernovae or black holes.
One mile below the surface, the detector will be nearly four stories tall and filled with 70,000 tons of liquid argon called to minus 300 degrees Fahrenheit. It will be on the receiving end of a beam of neutrinos sent from Fermilab in Illinios, 800 miles away. When a neutrino passes through the tank and interacts with an atom of argon, it should give off a flash of light. The underground location is meant to screen out other radiation including cosmic rays that could set off the detector.
DUNE and BACON
DUNE was conceived, designed and will be built by a team of 1,000 scientists and engineers from more than 160 institutions in 30 countries. UC Davis Physics Professor Robert Svoboda was principal investigator of the project from 2009 to 2014, and project spokesperson from 2010 to 2013.
“We got the project rolling and set up the initial scientific collaboration, including having the very first LBNF meeting in South Dakota,” Svoboda said. Current UC Davis personnel working on the project include Svoboda, Professor Emilija Pantic, postdoctoral researcher Jingbo Wang, graduate student Steven Gardiner and Hans Berns, research engineer at the Crocker Nuclear Laboratory.
As part of the project, the UC Davis team has been carrying out experiments to predict what DUNE will be able to see. For example, the BACON (Bucket of Argon Counting Neutrons) experiment at the Crocker Nuclear Lab was designed to measure the “background noise” caused by neutrons. By placing a small tank of argon in the path of the neutron beam from the Crocker lab’s cyclotron, the team could measure the likely “neutron noise” in an argon neutrino detector so it could be removed from the experiment.
The team is also working on a related experiment at the Los Alamos National Laboratory, and carrying out basic research and development for “Theia,” a future neutrino detector.
Deep Dark Matter Laboratory
Svoboda, Professor Mani Tripathi and other UC Davis researchers also worked on the LUX (Large Underground Xenon) experiment at the Sanford lab. The experiment was designed to look for Weakly Interacting Massive Particles or WIMPs, a candidate for the “dark matter” particles that make up about a quarter of the universe.
LUX completed its experimental run in 2016 without detecting any WIMPs but having successfully ruled out a wide range of masses for a potential dark matter particle.
The Sanford Underground Research Facility is located in the former Homestake gold mine near Lead, South Dakota. The mine closed in 2000, and in 2007 it was selected by the National Science Foundation as the site for a national underground science laboratory. The DUNE project is funded by the U.S. Department of Energy Office of Science in conjunction with CERN and international partners from 30 countries.
News release from Fermilab
UC Davis News: Supernovae Go Better With BACON (story and video)