The MiniBooNE detector tank holds 807 tons of ultra-pure mineral oil. Neutrinos colliding with the nuclei of atoms in the oil create charged particles, and these charged particles in turn generate light that the photomultiplier tubes detect. The detector enclosure lies beneath 20 feet of earth; this overburden provides additional shielding against incoming cosmic rays.
MiniBooNE not only tests the LSND result, it reuses a significant amount of LSND's equipment. About three-fourths of MiniBooNE's photomultiplier tubes, along with a good bit of electronics and part of the data acquisition system are being recycled from LSND.
While MiniBooNE shares some components and a few design features with the LSND detector, there are some significant differences, as well. LSND added chemical dopants to the mineral oil in its tank to increase the amount of a certain kind of light produced by the charged particles zipping through the oil; MiniBooNE uses undoped oil. The MiniBooNE tank is spherical, avoiding any potential "corner" issues that might have arisen with LSND's cylindrical tank. The MiniBooNE tank is also completely surrounded by veto shielding to better reject incoming cosmic ray particles.
The beam that passes through the MiniBooNE detector starts out as just about 100% muon neutrinos. If we detect more electron neutrino events than we expect, we'll have confirmed the oscillation of muon neutrinos to electron neutrinos seen by LSND.
|Mineral oil arrives at Fermilab railhead.|