Measuring Cosmic Ray and Atmospheric Neutrinos in the Sudbury Neutrino Observatory

High energy muons and neutrinos are produced by the interaction of primary cosmic rays in the Earth's upper atmosphere. These primary interactions produce mesons that decay into muons and neutrinos. SNO is in a unique position amongst underground experiments in the world. At the depth of over 6 km water equivalent, it is the deepest underground laboratory currently in operation. SNO can make a number of novel measurements using muons. First, SNO is sensitive to the downward muon rate coming from primary cosmic ray interactions. Second, SNO's great depth makes possible the detection of atmospheric neutrinos (via the detection of neutrino induced muons) from the nadir to inclinations as large as cos (θ zenith ) ≃ 0.4 above the horizon. Although SNO is a modest-size Cherenkov detector, SNO's unique niche allows it to make important model-independent checks of atmospheric neutrino oscillations.