The Sudbury Neutrino Observatory

This site is an archive of the achievements of the Carleton University physicists involved in the highly successful  Sudbury Neutrino Observatory (SNO) project from 2001-2011. 

The Sudbury Neutrino Observatory (SNO) was built as a water Cherenkov detector dedicated to investigate elementary particles called neutrinos. It was built  2070 m below the surface in shaft number 9 of the INCO Creighton Nickel Mine near Sudbury, Ontario.

Prior to the SNO project, all of the solar neutrino experiments conducted had detected only a fraction of the number of expected neutrinos from the sun. This is called the Solar Neutrino Problem.

It was thought that If the previous experiments were correct, then either the general understanding of the sun is seriously wrong, or 'neutrino oscillations' (which imply a non-zero neutrino mass) are reducing the number of detected electron neutrinos.

SNO was designed to determine whether the currently observed solar neutrino deficit is a result of neutrino oscillations. The detector was unique in its use of heavy water as a detection medium, permitting it to make a solar model-independent test of the neutrino oscillation hypothesis by comparison of the charged- and neutral-current interaction rates.