Image credit: Fermilab.
The particle detector for MicroBooNE, a new short-baseline neutrino experiment at Fermi National Accelerator Laboratory, was gently lowered into place on 23 June. It is expected to detect its first neutrinos this winter.
The detector – a time-projection chamber surrounded by a 12-m-long cylindrical vessel – was carefully transported by truck across the Fermilab site, from the assembly building where the detector was constructed to the experimental hall nearly 5 km away. The 30-tonne object was then hoisted up by a crane, lowered through the open roof of a new building and placed into its permanent home, directly in the path of Fermilab’s Booster neutrino beamline.
When filled with 170 tonnes of liquid argon, MicroBooNE will look for low-energy neutrino oscillations to help to resolve the origin of a mysterious low-energy excess of particle events seen by the MiniBooNE experiment, which used the same beam line and relied on a Cherenkov detector filled with mineral oil.
The MicroBooNE time-projection chamber is the largest ever built in the US and is equipped with 8256 delicate gold-plated wires. The three layers of wires will capture pictures of particle interactions at different points in space and time. The superb resolution of the time-projection chamber will allow scientists to check whether the excess of MiniBooNE events is due to photons or electrons.
Using one of the most sophisticated processing programs ever designed for a neutrino experiment, computers will sift through the thousands of neutrino interactions recorded every day and create 3D images of the most interesting ones. The MicroBooNE team will use that data to learn more about neutrino oscillations and to narrow the search for a hypothesized fourth type of neutrino.
MicroBooNE is a cornerstone of Fermilab’s short-baseline neutrino programme, which could also see the addition of two more neutrino detectors along the Booster neutrino beamline, to refute or confirm hints of a fourth type of neutrino first reported by the LSND collaboration at Los Alamos National Laboratory. In its recent report, the Particle Physics Project Prioritization Panel (P5) expressed strong support for a short-baseline neutrino programme at Fermilab. The report was commissioned by the High Energy Physics Advisory Panel, which advises both the US Department of Energy and the National Science Foundation on funding priorities.
The detector technology used in MicroBooNE will serve as a prototype for a much larger liquid-argon detector that has been proposed as part of a long-baseline neutrino facility to be hosted at Fermilab. The P5 report strongly supports this larger experiment, which will be designed and funded through a global collaboration.
