On 23–26 January, more than 230 members of the international Deep Underground Neutrino Experiment (DUNE) collaboration met at CERN to discuss the project’s status and plans. A main focus of the meeting was to coordinate the assembly of prototype modules for the vast DUNE detector, which are being constructed in a new facility on the CERN site (see “ProtoDUNE revealed”).
DUNE will comprise four detector modules with a total of 68,000 tonnes of liquid argon to detect neutrinos and look for rare subatomic phenomena such as proton decay. It will be situated 1.5 km underground at Sanford Underground Research Facility (SURF) in South Dakota, US. The experiment will be the target for intense beams of neutrinos and antineutrinos produced by a new facility to be built at Fermilab 1300 km away, and will address specific puzzles such as the neutrino mass hierarchy and CP violation in the neutrino sector.
CERN is playing a significant role in the DUNE programme via its recently established neutrino platform (CERN Courier July/August 2016 p21). A collaboration agreement was signed between CERN and the US in December 2015, in which CERN committed to the construction of prototype DUNE detectors and the delivery of one cryostat for the experiment in the US. Two large “protoDUNE” detectors are now taking shape in a new building in the north area of the CERN site.
DUNE aims to be for the neutrino what the LHC is for the Higgs boson, and enormous progress has been made in the past two years. Formed in early 2015, the collaboration now comprises 945 scientists and engineers from 161 institutions in 30 nations and is still growing, with about 60% of the collaborating institutions located outside the US. In September 2016, the US Department of Energy approved the excavation of the first caverns for DUNE, with preparatory work expected to begin at SURF this summer. A small, 3 × 1 × 1 m3 dual-phase demonstrator module constructed at CERN is also ready for filling and operation.
One of the highlights of the CERN meeting was a tour of the construction site for the large protoDUNE detectors. The vessel for the cryostat of the 6 × 6 × 6 m3 single-phase liquid-argon prototype module is almost complete, and the construction of an identical cryostat for a dual-phase detector will start soon. Preparing for the installation of liquid-argon time-projection-chamber (TPC) detector components, which will start this summer, was one of the main focuses of the meeting. Both single- and dual-phase protoDUNE detectors are scheduled to be operational and take data with the tertiary charged-particle beam from the Super Proton Synchrotron in 2018.
The DUNE collaboration is also starting to prepare a Technical Design Report (TDR) for the large underground detectors at SURF, and is working on the conceptual design for the DUNE near detector that will be placed about 55 m underground at the Fermilab site to measure neutrino interactions close to the source before the neutrinos start to oscillate.
Discussions about the responsibilities for building the vast number of detector components for the DUNE far detectors have begun, and additional scientists and institutions are welcome to join the collaboration. The goal is to finish the TDR for review in 2019 and to begin the construction of the far-detector components in 2021, with the first detector modules at SURF operational in 2024.