Proposal to Build a Neutrino Observatory in Sudbury, Canada

The proposal to build a heavy-water Cerenkov detector deep underground is discussed. The main physics objectives are to measure the8B solar neutrino flux, to identify neutrino oscillations and to watch for gravitational collapse. The measurements of the sources of background and the optical properties of heavy water, which are necessary to prove the feasibility of the detector, are reported. The present status of the project is indicated.