Underground Neutrino Detector

Sudbury Neutrino Observatory

The Sudbury Neutrino Observatory held in the Creighton Mine of Sudbury, Ontario, Canada.
Image Credit/Copyright: Lawrence Berkeley Nat'l Lab - Roy Kaltschmidt, photographer

Until 2006, the Sudbury Neutrino Observatory searched for fusion artifacts emerging from the heart of the Sun — neutrinos. Neutrinos are neutral subatomic particles that come in three flavors: electron, muon, and tau.

When neutrinos interact with heavy water, they emit a detectable radiation. Heavy water has higher amounts of deuterium — an isotope of hydrogen that has one neutron as opposed to the typical zero neutrons found in most hydrogen atoms.

SNO has an enormous 1000-ton tank of such water, seen in the sphere above. The experiment's almost 10,000 light detectors  pick up on the emitted radiation from the water-neutrino interaction.

Scientists are still analyzing the data collected from this experiment even though it's been offline for years. Analyses from the experiment have gleaned new information on the abundance of neutrinos and revealed that neutrinos can oscillate among their three flavors.

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