Direct Evidence for Neutrino Flavour Transformation from Neutral Current Interactions in SNO

The Sudbury Neutrino Observatory is a 1 kilotonne D₂O Cerenkov detector designed to determine whether the currently observed solar neutrino deficit is a result of neutrino oscillations. Recent results confirming this hypothesis from 306 days of data will be presented. The analysis is based on observations of neutrinos from the decay of ⁸B via the charged current (CC) and Neutral Current (NC) reactions on deuterium and the elastic scattering (ES) of electrons above thresholds of 2.2 MeV (NC) and 5 MeV (CC and ES). This is the first direct measurement of the total flux of active ⁸B neutrinos arriving form the Sun. It is determined to be in good agreement with the predictions of solar models. The analysis will be discussed in the context of the Solar Neutrino Problem and the future science program at SNO will be presented, with mention of the challenging requirements of ultra-low levels of radioactivity.