MINOS, or Main Injector Neutrino Oscillation Search, is an experiment at Fermilab designed to study the phenomena of neutrino oscillations.
MINOS is a long baseline neutrino oscillation experiment. An intense beam of neutrinos is made at the Main Injector particle accelerator at Fermilab (near Chicago), and travels 735km through the earth to the Soudan mine in northern Minnesota. At its source the beam is mostly made of muon neutrinos with a small background of electron neutrinos. The energy spectrum of neutrinos of each flavour (electron, muon, tau) is measured in the "Near Detector" at Fermilab and the "Far Detector" in the Soudan Mine. MINOS then compares the spectra measured in the two detectors to understand if the flavour content of the beam changes as it propagates and, if so, how the changes depend on neutrino energy. The data is used to test theories, such as neutrino oscillations, which predict flavour changes.
MINOS began collecting beam data in March 2005 and is currently a running experiment which has already provided the world's best measurement of the neutrino oscillation parameter associated with the difference between the second and third neutrino mass state. The Far Detector has been recording atmospheric neutrino and cosmic ray data since construction was completed in the summer of 2003. The Near Detector's primary role is to determine the initial flavour content of the neutrino beam. However, the large quantity of data collected by the Near detector will also be used to measure neutrino cross sections and nucleon structure.
The MINOS collaboration involves US, UK, Poland, Greece and Russia.
STFC Rutherford Appleton Laboratory
University College London
University of Cambridge
University of Oxford
University of Sussex