Scientists have spent years puzzling over the apparent gap between the number of neutrinos thought to be generated in the core of the sun and the number detected on earth. Either something was profoundly wrong with our model of fusion reactions in the sun, or many of the elusive subatomic particles that are considered the basic building blocks of the universe somehow disappeared en route.
After painstakingly designing and building the Sudbury Neutrino Observatory (SNO), a Canadian-led team finally confirmed in 2002 that neutrinos escape detection because they spontaneously change their "flavour," or type, after leaving the sun. The results confirmed not only that the models of energy generation in the sun are correct, but that the most basic laws of physics are incomplete. The discovery provided revolutionary insight into the fundamental nature of matter and was one of the top scientific breakthroughs of the year.
SNO sits in a mineshaft two kilometres underground. The massive rock shield overhead and the cleanliness of the laboratory makes for what is considered the world's lowest-radioactivity experimental location. The SNO detector is built around 1,000 tonnes of heavy water in an acrylic vessel. As neutrinos pass through the water, they produce flashes of light called Cherenkov radiation, which are detected by an array of 9,600 photomultiplier tubes.
Members of the Sudbury Neutrino Observatory Team
Dr. Alain Bellerive, Carleton University
Dr. Mark Boulay, Queen's University
Dr. Mark Chen, Queen's University
Dr. Hugh Evans, Queen's University
Dr. George Ewan, Queen's University
Dr. Jacques Farine, Laurentian University
Dr. Aksel Hallin, Queen's University
Dr. Douglas Hallman, Laurentian University
Dr. Cliff Hargrove, Carleton University
Dr. Rich Helmer, TRIUMF
Dr. Richard Hemingway, Carleton University
Dr. Jimmy Law, University of Guelph
Dr. Hamish Leslie, Queen's University
Dr. Hay-Boon Mak, Queen's University
Dr. Arthur McDonald, Queen's University
Dr. Anthony Noble, Queen's University
Dr. Robin Ollerhead, University of Guelph
Dr. Scott Oser, University of British Columbia
Dr. Barry Robertson, Queen's University
Dr. David Sinclair, Carleton University
Dr. Clarence Virtue, Laurentian University
Dr. Christopher Waltham, University of British Columbia