Click on images for high-resolution jpeg images. When using these images, please credit Fermilab.
The MiniBooNE experiment relies on a 250,000-gallon tank filled with mineral oil, which is clearer than water from a faucet. Light-sensitive devices (PMTs) mounted inside the tank are capable of detecting collisions between neutrinos and carbon nuclei of oil molecules
A close-up view of the MiniBooNE tank shows the inner layer of 1280 photomultiplier tubes (PMTs) that detects neutrinos produced by Fermilab's Booster accelerator. A second layer of 240 PMTs, still inside the tank but facing outward, detects signals caused by cosmic ray showers.
The observations made by the LSND experiment in the 1990s suggested the
presence of neutrino oscillation in a neutrino mass region (blue shaded
areas) vastly different from other experiments (which are outside the region
shown in this plot, at much smaller values of Δ m2). The MiniBooNE
experiment rules out the region to the right of the black and blue lines,
ruling out the simple two-neutrino oscillation interpretation of the LSND
The top plot shows the raw number of electron neutrino events recorded by
the MiniBooNE experiment (black dots). The bottom plot shows the number of
excess events observed after subtracting the background. The solid curves in
the bottom plot show two examples (green and purple curves) of predictions
made for electron neutrino excess according to the two-neutrino oscillation
interpretation of the LSND results. The MiniBooNE data rule out such
two-neutrino oscillation predictions.
MiniBooNE cospokesperson Bill Louis, here checking the MiniBooNE data acquisition system, is a scientist at Los Alamos National Laboratory. In the 1990s, he worked on the LSND experiment, which triggered the idea for the MiniBooNE experiment.
A close-up of the interior of the MiniBooNE tank, before it was filled with ultrapure mineral oil.
Filling of oil into MiniBooNE Tank
Take a virtual tour of MiniBooNE