Soudan 2 was aparticle detector located in theSoudan Mine in Northern Minnesota, United States, that operated from 1989 to 2001. It was a 960-ton iron trackingcalorimeter whose primary purpose was to search forproton decay, although its data were also used to investigate the properties ofneutrinos. It found no evidence of proton decay, but it did help confirmSuper-Kamiokande's atmospheric neutrino result, supporting the theory ofneutrino oscillation.[1]
The Soudan Mine was also home to theMINOS andCDMS detectors.
Soudan 2 was the successor to theSoudan 1, a similar 30 ton detector also intended to search for proton decay.[2]
The excavation for Soudan 2 was done in 1984–1985. Installation was started in 1986 and was completed in 1993. The experiment was run from April 1989 to June 2001, beginning with a partial detector of 275 tons.[3] It was disassembled in 2005 to make room for further lowbackground physics experiments, includingMINOS.