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Sudbury Neutrino Observatory Wins First Polanyi Award

SUDBURY, ONTARIO - The winners of the inaugural $250,000 NSERC John C. Polanyi Award are the scientists at the Sudbury Neutrino Observatory (SNO), who are being honoured for their groundbreaking research on neutrinos, announced Natural Sciences and Engineering Research Council (NSERC) President Suzanne Fortier.

SNO operates a $100 million detector housed in the world's deepest underground laboratory at Inco Ltd.'s Creighton nickel mine near Sudbury, Ont. The heart of this detector is a 10-storey cavern excavated by Inco miners. There you will find the world's largest acrylic vessel, holding 1,000 tonnes of heavy water on loan from Atomic Energy of Canada Ltd. (AECL) and worth an additional $330 million. In contrast to its massive size, the detector is used to look for neutrinos, tiny subatomic particles that make up all matter in the universe.

Photo of Raymond Davis

The idea behind SNO’s most notable achievement – proving that the type of neutrinos released from the sun can “disappear” as they travel to earth by switching into the other two known neutrino types – began with Brookhaven chemist and Nobel Laureate Ray Davis Jr. in the early 1970s. In an experiment set up in a South Dakota gold mine, Davis confirmed that the sun produces neutrinos, but also found that only about one-third of the number of neutrinos predicted by theory could be detected on earth.

Neutrinos are extremely difficult to detect, because they can pass through most forms of matter easily. In fact, billions of neutrinos pass through people's bodies every second with no noticeable effect, and it would take a block of lead one light-year thick (about 10,000,000,000,000 kilometres) to stop even half of any neutrino stream.

The heavy water in the SNO detector allows the detection of these ghostly particles on the rare occurrences where they crash directly into an electron or a nucleus of an atom in a heavy water molecule. The collisions emit small pulses of light, which are captured by 9,600 photomultiplier tubes that surround the heavy water vessel. False signals from cosmic rays and other radiation are kept to a minimum by the two kilometres of rock above and an obsession for cleanliness at this unique underground facility.

The SNO team gained international recognition by proving that neutrinos released in the core of the sun change their "flavour" or type as they travel to earth. About two-thirds of them change into two other types of neutrinos, not visible to earlier detectors used at other laboratories.

Finding these "missing" neutrinos solved a 30-year-old scientific problem: the discrepancy between the number of neutrinos observed and the previous predictions of theoretical models for the sun. The SNO measurements also proved that the most basic laws of physics are incomplete. SNO research data also has led to a more complete description of nature at the subatomic level.

The SNO team being honoured includes scientists from Queen's University, Carleton University, Laurentian University, the University of British Columbia, the University of Guelph, AECL, TRIUMF, and the National Research Council. As well, SNO has a number of international partners. The American partners include the University of Pennsylvania, Los Alamos National Laboratory, Lawrence Berkeley National Laboratory, University of Washington, Brookhaven National Laboratory, the University of Texas at Austin and Louisiana State University. In Europe, SNO partners include Oxford University, Rutherford Appleton Laboratory, the University of Sussex, and Laboratório de Instrumentação e Física Experimental de Partículas in Lisbon.

"This award is a recognition of the excellent work by a great international team of scientists and dedicated laboratory staff members," said SNO Director Art McDonald.

"NSERC has been the single largest funder of SNO since its inception and I am very proud of the research accomplishments of the scientists who have so ably taken advantage of this tremendous research tool," said Fortier. "Given the wonderful example they offer as discoverers par excellence to Canadians everywhere, this award, named for a Canadian Nobel prizewinner, is well deserved."

About John C. Polanyi

John C. Polanyi made Canada proud when he won the 1986 Nobel Prize in Chemistry. Thirty years before, Polanyi had begun his groundbreaking work documenting the energy status and movements of molecules at the very moment of chemical reaction. Through his molecular beam and infrared chemiluminescence experiments, he clarified chemical dynamics right down to the level of atoms and molecules. His discoveries dramatically advanced the understanding of the physics of chemical reactions and led to the development of powerful new lasers.


NSERC is a federal agency whose role is to make investments in people, discovery and innovation for the benefit of all Canadians. The agency supports some 22,000 university students and postdoctoral fellows in their advanced studies. NSERC promotes discovery by funding more than 10,000 university professors every year and fosters innovation by encouraging more than 800 Canadian companies to participate and invest in university research projects.

For more information, contact:
Michael Dwyer
Media and Public Affairs Officer
NSERC Public Affairs
Tel.: 613-992-9001
Cell: 613-794-9170

Tags: physics

2006-563  |  Media & Communications Office