![]() Ninety-eight percent of IceCubes over 5,000 DOMs are working perfectly, and another one percent are usable reassuring numbers, given that the DOMs now frozen in the ice will never be seen again. Their superb performance resulted in the DOM technology being selected for IceCube.īerkeley Labs built-in electronics have performed with astonishing dependability. Robert Stokstad and David Nygren of Berkeley Labs Nuclear Science and Physics Divisions developed and championed the idea of digital optical modules and led the String 18 operation, with Physics Division engineer Jerry Przybylski doing much of the hardware work. The PMTs and circuit boards are housed together in transparent glass pressure vessels.īerkeley Lab and the University of Wisconsin worked together with other institutions to design and build String 18, a single string of 40 prototype DOMs installed at AMANDA in 2000. Electronics convert the PMT signals to digital form. Called Digital Optical Modules (DOMs), their optical parts are photomultiplier tubes (PMTs) that detect and amplify Cherenkov radiation from passing muons. Sixty basketball-sized detectors are mounted on each IceCube string. Because these muons (and other debris from the collision) are moving faster than light can travel through ice, they radiate a shock wave of blue Cherenkov radiation visible to IceCubes photodetectors.Ĭatching neutrinos with Digital Optical Modules Seeing them at all is only possible because when neutrinos collide with the nuclei of oxygen atoms in the ice, they turn into energetic charged particles called muons, moving in the same direction. The telescope has to be this big because neutrino collisions with matter are exceedingly rare: out of uncounted trillions of neutrinos constantly passing through the ice, IceCube will observe just a few hundred a day. Under construction since 2004, IceCube encloses a cubic kilometer of clear ice, beginning one and a half kilometers beneath the surface and extending downward another kilometer. Department of Energys Lawrence Berkeley National Laboratory has been a major contributor to the design and construction of its key components. IceCube is supported largely by the National Science Foundation and led by the University of Wisconsin-Madison. Members of the IceCube Collaboration celebrated the event at the South Pole and around the world, at about 40 affiliated institutions located in the U.S., Germany, Belgium, Sweden, Barbados, Canada, Japan, New Zealand, Switzerland, and the United Kingdom. ∿inally science can start with a stable instrument that already yields neutrinos with unprecedented energy and statistics. With the completion of IceCube, the 1970s dream of building a kilometer-scale neutrino detector has finally become a reality, says Francis Halzen, a professor of physics at the University of Wisconsin-Madison and the IceCube Collaborations principal investigator.
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