The Sudbury Neutrino Observatory (SNO) was a neutrino observatory located 2100 m underground in Vale's Creighton Mine in Sudbury, Ontario, Canada. The detector was designed to detect solar neutrinos through their interactions with a large tank of heavy water.
The detector was turned on in May 1999, and was turned off on 28 November 2006. The SNO collaboration is actively analyzing the data taken.
The director of the experiment, Art McDonald, was co-awarded the Nobel Prize in Physics in 2015 for the experiment's contribution to the discovery of neutrino oscillation.
The underground laboratory has been enlarged into a permanent facility and now operates multiple experiments as SNOLAB. The SNO equipment itself is currently being refurbished for use in the SNO+ experiment.