| Funded
in 1990, the Sudbury Neutrino Observatory is a unique facility which is measuring
neutrinos from the sun in a $ 75 million laboratory, 2000 meters underground in
Inco's Creighton Mine about 25 minutes from the university. Planned and operated
by scientists from 12 institutions in Canada, the United States, and the United
Kingdom, SNO began its measurements in 1999, and in 2001 published major findings
which showed that neutrinos oscillate from one species to another on their way
from the sun. When neutrinos of all species are included, the total measured flux
of solar neutrinos now agrees with the best solar theories - the solar neutrino
problem - a large discrepancy of earlier experimental measurements at other laboratories
with predictions - has been solved. Over a five year measurement period, precision
measurements of this neutrino mixing have been made, and a small mass (actually
a mass difference) is now assigned to neutrino species. The SNO experiment is
now in its third phase of neutrino measurements, in which 3He neutron counters
are inserted in the heavy water core, to add to the precision of SNO's neutral
current reaction measurements. See the SNO web site (http://www.sno.phy.queensu.ca)
for lots more information. |
