ANTARES (telescope)
From Wikipedia, the free encyclopedia
ANTARES is the name of a neutrino telescope currently under construction that will reside in the Mediterranean Sea off the coast of Toulon, France. It will observe neutrinos from the Southern Hemisphere to complement the northern hemisphere work of IceCube. The name comes from Astronomy with a Neutrino Telescope and Abyss environmental RESearch project; the acronym also being the name of a prominent star. Other neutrino telescopes designed for use in the nearby area include the Greek NESTOR telescope and the Italian NEMO telescope , which are both in early design stages.
When complete, the array will contain a set of twelve different strings of photomultiplier tubes. Each one will have 75 optical modules, measure about 350 meters long, and be spaced roughly 70 meters apart. Unlike traditional telescopes, ANTARES works by facing downward, into the earth. This is because the earth is nearly transparent to neutrinos. When neutrinos enter the southern hemisphere of the earth, they usually continue traveling directly through it. Facing downward filters out many of the noisy atmospheric muons. On rare occasions, a few muon neutrinos interact with the water in the Mediterranean Sea. When this happens, they produce high energy muons. As the muons pass through the water, they emit Cherenkov radiation, which ANTARES expects to detect on the photomultiplier tubes.
ANTARES uses water instead of ice as its Cherenkov medium. As light in water is less scattered than in ice this results in a better resolving power. On the other hand water contains more sources of background light than ice (radioactive isotopes of sea salt and bioluminescent organisms) which leads to a higher energy thresholds for ANTARES with respect to IceCube.
[edit] Construction status
As of February 2007, ANTARES is well advanced in its construction. Initial testing began in 2000. Equipment indirectly related to the detector such as a seismometer were deployed in 2005. The first string of photomulitplier tubes was moved into place in February 2006 and is fully functional. On September 21st, the second line has been successfully connected. The third, forth and fifth line has been deployed end of 2006 and have been connected in January 2007. This important step makes Antares the biggest neutrino telescope in the Northern hemisphere (surpassing the Baikal neutrino telescope).
[edit] Experimental goals
The ANTARES project plans to be a counterpart to IceCube. The detection principles of the two projects are very similar, and they point toward opposite hemispheres. ANTARES will detect neutrinos from high energy origin, particularly in the range from 1011 to 1021 electron-volts. Over several years of operation, it may be able to produce a map of the neutrino flux from cosmic origins in the southern hemisphere. It may also help answer some of the unsolved problems in physics including the appearance of dark matter and the unobserved prediction in string theory of a sterile neutrino, made from a closed string.
