How the LBNE would fit into the Fermilab accelerator complex. Courtesy Fermilab.
Work toward the world’s most intense long-distance neutrino beam received key government approval last week, invigorating US and global collaborators.
The Long Baseline Neutrino Experiment passed the first Department of Energy approval stage Friday, Jan. 8, when it received Critical Decision-0. This designation cements the DOE’s support for the need and physics goals of the experiment. In a field where researchers work on multiple projects at once, the designation also helps laboratories prioritize efforts.
“The fact that we have CD-0 motivates scientists and engineers to give this project a larger fraction of their time, optimize efforts and make faster progress,” says Vaia Papadimitriou, project manager for the Fermilab Neutrino Beam Facility.
LBNE will use the Main Injector accelerator at Fermilab to produce protons that collide with a fixed target to generate a beam of muon neutrinos. This neutrino beam will strike a small detector on the Fermilab site and then travel more than 620 miles to strike an underground detector more than 10 times the size of the largest LHC detector.
Three caverns, each as tall as a 20-story building and located deep underground, are necessary to build a 300-kiloton Water Cerenkov detector. Scientists are also advancing the R&D for liquid-argon detectors, which would be smaller but more difficult to build. Courtesy DUSEL
The experiment could help explain the matter/antimatter asymmetry we see in the universe today and determine the ordering of the three light-neutrino masses.
Physicists and engineers have made substantial R&D design progress already toward this cutting-edge, one-of-a-kind experiment. LBNE will create the world’s most intense neutrino beam. The beam will start at 700 kilowatts of power, close to double the power of the NuMI beam. Scientists can upgrade the LBNE beam's power in the future to increase the intensity and quicken the pace to discovery.
The mammoth far detector, which may sit in the proposed DUSEL facility in the Homestake Mine in South Dakota, will test liquid particle detection capability at a volume never before attempted. Collaborators continue to investigate which detector option to pursue: water Cerenkov technology like that used at Super-Kamiokande in Japan, or a less-developed technology known as a liquid-argon time projection chamber, which is planned for Fermilab’s MicroBooNE experiment.
On the accelerator side of the experiment, collaborators continue to work toward optimizing the design. Several engineers and scientists from Facilities Engineering Services Section, Technical, Accelerator and Particle Physics divisions and the Accelerator Physics Center have joined in to help design civil structures, magnets, targets, horns, absorbers, and many other technical components.
The design of a high-power target is a particularly challenging task. Fermilab staff is performing this R&D work with the help of IHEP in Russia, Brookhaven and Argonne national laboratories, and Rutherford Appleton Laboratory in the United Kingdom. For example, about a half a dozen possible target materials will be studied at the Brookhaven Linac Isotope Producer, or BLIP, facility.
Ground coring of Fermilab’s site is expected to finish by mid-January. Scientists expect the coring report due in mid-February to validate assumptions about soil and rock quality and ground-water conditions. This information will advance the civil construction conceptual design.
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How to make neutrinos with a fixed target. Courtesy Fermilab.
Preliminary design on-site work plans include constructing a new 1900-foot-long primary beamline off the current NuMI line, installing a fixed target, digging a particle decay tunnel 820 feet long and 13 feet in diameter and placing a small detector underground on the Fermilab site near Kirk Road. In total, that will require the excavation of about 60,000 cubic yards of rock and the movement of 40,000 cubic yards of earth.
By March collaborators expect an optimized neutrino beamline configuration, and by May the civil construction conceptual design.
