College Park, MD (August 31, 2010) -- In December 2010, IceCube -- the world's first kilometer-scale neutrino observatory, whiuch is located beneath the Antarctic ice -- will finally be completed after two decades of planning. In an article in the AIP's Review of Scientific Instruments, Francis Halzen, the principal investigator of the IceCube project, and his colleague Spencer Klein of Lawrence Berkeley National Laboratory provide a comprehensive description of the observatory, its instrumentation, and its scientific mission--including its most publicized goal: finding the sources of cosmic rays.
"Almost a century after their discovery, we do not know from where the most energetic particles to hit the Earth originate and how they acquire their incredible energies," says Halzen, a professor of physics at the University of Wisconsin in Madison.
After light, neutrinos, which are created in the decay of radioactive particles, are the most abundant particles in the universe. High-energy neutrinos are formed in the universe's most violent events, like exploding stars and gamma ray bursts. Because the neutrino has no charge, essentially no mass, and only interacts weakly with matter, trillions of neutrinos pass through our bodies each day, without effect. On extremely rare occasions, a neutrino will strike the nucleus of an atom, creating a particle, called a muon, and blue light that can be detected with optical sensors. The trick is spying those collisions--and, in particular, the collisions of high-energy neutrinos. IceCube does it by sheer virtue of its size.
At 1 kilometer on a side -- with 5,160 optical sensors occupying a gigaton of ice -- the observatory is orders of magnitude bigger than other neutrino detectors; the Superkamiokande detector in the Japanese Alps, for example, is only 40 meters on a side.
"IceCube has been totally optimized for size in order to be sensitive to the very small neutrino fluxes that may reveal the sources of cosmic rays and the particle nature of dark matter," Halzen says.
The article, "IceCube: An instrument for neutrino astronomy" by Francis Halzen and Spencer R. Klein appears in the journal Review of Scientific Instruments. See: http://rsi.
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This work is supported by the National Science Foundation.
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First Image Caption: Signals from the sensors are carried by cables to the IceCube counting house that houses a large cluster of computers to reconstruct in real time some 2,000 muon tracks every second. (Photo by J. Haugen, This material is based upon work supported by the National Science Foundation. The news media is free to use the image.)
Second Image Caption: IceCube scientists deploy a calibration light source, called the Standard Candle in one of the 2.5 km deep holes. Each of the 86 holes contains a string of 60 Digital Optical Modules (DOMs) that detect the blue light from neutrino events in the deep, clear ice. (Photo by J. Haugen, This material is based upon work supported by the National Science Foundation. The news media is free to use the image.)
REVIEW OF SCIENTIFIC INSTRUMENTS
Review of Scientific Instruments, published by the American Institute of Physics, is devoted to scientific instruments, apparatus, and techniques. Its contents include original and review articles on instruments in physics, chemistry, and the life sciences; and sections on new instruments and new materials. One volume is published annually. Conference proceedings are occasionally published and supplied in addition to the Journal's scheduled monthly issues. RSI publishes information on instruments, apparatus, techniques of experimental measurement, and related mathematical analysis. Since the use of instruments is not confined to the physical sciences, the journal welcomes contributions from any of the physical and biological sciences and from related cross-disciplinary areas of science and technology. See: http://rsi.
The American Institute of Physics is a federation of 10 physical science societies representing more than 135,000 scientists, engineers, and educators and is one of the world's largest publishers of scientific information in the physical sciences. Offering partnership solutions for scientific societies and for similar organizations in science and engineering, AIP is a leader in the field of electronic publishing of scholarly journals. AIP publishes 12 journals (some of which are the most highly cited in their respective fields), two magazines, including its flagship publication Physics Today; and the AIP Conference Proceedings series. Its online publishing platform Scitation hosts nearly two million articles from more than 185 scholarly journals and other publications of 28 learned society publishers.