Department of Physics, Engineering Physics & Astronomy

Department of Physics, Engineering Physics & Astronomy
Department of Physics, Engineering Physics & Astronomy

How to Tell a Neutrino from a Hole in the Ground

Dr. Art McDonald
Department of Physics, Queen's University, Director of Sudbury Neutrino Observatory

Thursday, March 11, 2004
7:30 PM @ the ROM (The Royal Ontario Museum, Toronto)


Neutrinos, along with electrons and quarks, are presently thought to be fundamen­tal building blocks of matter…particles that we do not know how to subdivide further. Neutrinos are the least known of these particles because they have very small mass, interact only through the weak force, and penetrate through vast amounts of material without stopping. Neutrinos are produced copiously by the nuclear reac­tions that power the Sun and these solar neutrinos, if detected, can tell us a lot about the Sun and about neutrinos themselves. Canada has two tremendous advan­tages in the detection of neutrinos through large reserves of heavy water (used in the CANDU style of nuclear reactor) and an ideal site 2 km underground, away from the cosmic rays that would prevent the detection of neutrinos.

The Sudbury Neutrino Observatory (SNO), in INCO's Creighton mine near Sudbury has performed unique measurements of neutrinos that confirm our theories of the Sun in great detail and exhibit new properties of neutrinos that go beyond the previously accepted basic theories of physics. The SNO story to date will be told, including the enormous efforts required to build an experiment the size of a ten story building with ultra clean conditions in an active nickel mine and the very fundamental scientific results that have been obtained. Exciting future experiments in the expanded SNOLAB underground facility now under development will also be discussed.