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MiniBooNE opens the box

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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.

A neutrino signal observed by the MiniBooNE experiment.

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 data.

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 Janet Conrad, professor of physics at Columbia University, holds one of the 1520 light sensors (called photomultiplier tubes) installed inside the MiniBooNE detector.

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.

MiniBooNE Collaboration

The inside of the MiniBooNE tank is covered with 1280 inward-facing photomultiplier tubes. The picture shows a section of the upper hemisphere of the tank.

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

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Last modified: 04/28/2009 |