A Facility for the DUNE Experiment

DUNE is being designed to explore the field of neutrino physics using a high-intensity, accelerator-based neutrino beam, a long baseline for neutrino oscillations, a fine-grained near detector and a very large, deep underground detector. The effort to design, build and operate the envisioned experiment is divided between the entities that manage the facility (LBNF) and the experiment (DUNE). These entities are responsible for interacting with the funding agencies in the various countries to construct the experimental and conventional facilities.

The international LBNF Project has been formed to work with the DOE for construction of the U.S. portion of the facility, and with international funding agencies for the additional contributions. The DUNE collaboration is responsible for the design and construction of the experiment, i.e., the detectors.

Close and continuous coordination between DUNE and LBNF is required to ensure the success of the combined enterprise. An Experiment-Facility Interface Group oversees and ensures the required coordination during the current design phase, and will continue to do so during the construction and operational phases of the facility and the experiment.

Near Site Layout

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Courtesy Fermilab

The LBNF beamline will be built off of Fermilab's Main Injector, extracting a proton beam from this source (at MI-10 in the expanded figure) and will use magnets to direct the proton beam toward the DUNE detectors (the near detector will be under LBNF-40). Once the beam direction is established, the protons will smash into a target (at LBNF-20) creating secondary particles, most of which decay into neutrinos in the decay pipe and continue travelling in the same direction. An absorber (under LBNF-30) will stop the leftover secondaries, creating a very pure beam of neutrinos for the experiment.

Near Detector Spaces

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Courtesy Fermilab

The DUNE near detector will require LBNF to excavate and provision a cavern 200 ft (60 m) below grade on the Fermilab site and to construct a surface building directly above it. An elevator will provide the primary access between the two spaces; the stairway shown is planned for emergency egress. This complex will be constructed a minimum of 690 feet (210 m) downstream of the beamline target.

Far Detector Caverns

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Courtesy SURF

The DUNE far detector will consist of four modules, each of which will be housed in a cryostat containing 17,000 metric tons of liquid argon target material. LBNF will excavate and provision a set of four caverns — 5,000 ft (1500 m) underground — arranged as a pair of double caverns, in which to place them. The double caverns, aligned parallel to the beam, will each have 50 ft (15 m) of rock separating two end-to-end modules. A fifth cavern, between the pair, will house the cryogenics equipment.

LBNF will provide the cryostats as well as the cryogenics equipment that is used to maintain the argon in the liquid state and to keep it pure and circulating smoothly during operations.