View source for Irvine–Michigan–Brookhaven (detector)

'''IMB''', the '''Irvine-Michigan-Brookhaven detector''', was a [[nucleon]] decay experiment and [[neutrino]] [[observatory]] located in a [[Morton Salt]] company's  [[Fairport Harbor, Ohio|Fairport]] mine on the shore of [[Lake Erie]] in the [[United States]] 600 meters underground. It was a joint venture of the [[University of California, Irvine]], the [[University of Michigan]], and the [[Brookhaven National Laboratory]].<ref>The Underground Search for Clues to an Unstable Universe, [https://books.google.com/books?id=XBZpIPL1lloC&pg=PA64 Popular Science], Vol. 219, No. 8 (December, 1981); pages 64-67.</ref>  Like several other particle detectors (see ''[[Kamiokande II]]''), it was built primarily with the goal of observing [[proton decay]], but it achieved greater fame through neutrino observation, particularly those from Supernova [[SN 1987A]].<ref>[http://www-personal.umich.edu/~jcv/imb/imb.html John C. Vander Velde's IMB page], accessed 11 April 2008.</ref>

== Design == 

IMB consisted of a roughly [[cube|cubical]] tank about 17 × 17.5 × 23 meters, filled with 2.5 million gallons of [[ultrapure water]] which was surrounded by 2,048 [[photomultiplier]] tubes.<ref>[http://lss.fnal.gov/archive/test-proposal/0000/fermilab-proposal-0805.pdf A Proposal for a Long Baseline Oscillation Experiment Using A High Intensity Neutrino Beam from the Fermilab Main Injector to the IMB Water Cerenkov Detector; FNAL P805.]</ref>  IMB detected fast-moving particles such as those produced by proton decay or neutrino interactions by picking up the [[Cherenkov radiation]] generated when such a particle moves faster than light's speed in water.  Since directional information was available from the phototubes, IMB was able to estimate the initial direction of neutrinos.

== History ==

Ground was broken at the salt mine in 1979; the water tank for the detector itself was finished in 1981. The project was delayed by funding problems and leaks in the water tank, but by the end of summer 1982 the detector was operating at full capacity. The first results were published in 1982.<ref>"IMB Detector: The First 30-Days." D. Sinclair et al. 1982. Los Alamos 1982, Proceedings, Science Underground, pg. 138-142.</ref>  In 1987, it gained fame for detecting 8 of the roughly 10<sup>58</sup> [[Supernova neutrinos|neutrinos]] emitted by [[Supernova 1987A]].  This discovery was completely unexpected; supernovas as near as 1987a are extremely rare and virtually unpredictable.  The detector collected data until 1991.<ref>[http://www-meg.phys.cmu.edu/~clark/imb.html Russell J. Clark's IMB page] {{webarchive|url=https://web.archive.org/web/20041214041312/http://www-meg.phys.cmu.edu/~clark/imb.html |date=2004-12-14 }}, accessed 5 July 2006.</ref>

This volume of water contains on the order of 10<sup>31</sup> [[proton]]s. In one year of observation no proton decay event was recorded. This put the half-life of a proton at or above 10<sup>31</sup> years.

== References ==

<references/>

== External links ==
* [https://inspirehep.net/experiments/1109561 IMB experiment] record on [[INSPIRE-HEP]]
* "[https://www.cleveland.com/news/2024/08/a-star-exploded-in-a-distant-galaxy-and-it-made-history-at-morton-salt-170000-years-later.html A star exploded in a distant galaxy, and it made history in Northeast Ohio at Morton Salt 170,000 years later]" (''[[The Plain Dealer]]'', 30 August 2024)
* "[https://www.facebook.com/ohiodnr/posts/earlier-this-week-odnr-and-ohio-state-parks-unveiled-a-new-historical-marker-at-/970127705158105/ The Birth of Neutrino Astronomy]"<!-- official account; nothing yet at remarkableohio.org or hmdb.org --> marker, [[Ohio Department of Natural Resources]], May 2023

{{Neutrino detectors}}
{{Proton decay experiments}}

{{DEFAULTSORT:Irvine-Michigan-Brookhaven (Detector)}}
[[Category:Particle experiments]]
[[Category:Neutrino observatories]]
[[Category:University of Michigan]]