Main Injector Neutrino Oscillation Search: What is MINOS?

The Main Injector Neutrino Oscillation Search (MINOS) seeks to investigate the natural phenomena of neutrino oscillation. Neutrino oscillation, first observed in the 1960's, is predicted by quantum mechanics. The quantum mechanics suggests that though a neutrino is observed at a given time to be of a particular type or 'flavor' (electron neutrino, muon neutrino, or tau neutrino) if it has mass there is a probability that it can be observed later as a different flavor. For the neutrino to change flavor or 'oscillate,' it must have mass, which is contrary to the hypothesis in the standard model of particle physics.

The MINOS experiment begins at Fermi National Accelerator Laboratory (Fermilab or FNAL) in Batavia, IL. The NuMI beam (Neutrinos at the Main Injector) creates a concentrated beam of muon neutrinos aimed at Soudan Mine. This beam travels through the MINOS 'near detector' at Fermilab and then (455 miles later) through MINOS 'far detector.' The far detector is located 2341 feet below the surface of the Earth in Soudan Mine Lab.  MINOS searches for an absence of muon neutrino events as evidence of oscillation. This is done by comparing the 'before' data from the near detector to the 'after' data from the far detector.

Wilson Hall at Fermi National Accelerator Lab