Fig5_4 Sudbury Neutrino Observatory

Fig5_4 Sudbury Neutrino Observatory

Fig. 5.4 . Neutrinos from the Sun travel through more than two kilometers of rock, entering the acrylic tank of the Sudbury Neutrino Observatory, which contains 1,000 tons (1 million liters) of heavy water. When one of these neutrinos interacts with a water molecule, it produces a flash of light that is detected by a geodesic array of photo-multiplier tubes. Some 7,800 tons (7.8 million liters) of ordinary water surrounding the acrylic tank blocks radiation from the rock, while the overlying rock blocks energetic particles generated by cosmic rays in our atmosphere. The heavy water is sensitive to all three types of neutrinos.

Copyright 2010, Professor Kenneth R. Lang, Tufts University