Construction and operation of the ANTARES underwater neutrino telescope

The ANTARES underwater neutrino telescope is in an advanced stage of construction at a depth of 2500 m in the Mediterranean Sea near Toulon. The complete detector will contain 12 anchored detection lines, each equipped with 75 photomultipliers housed in glass pressure spheres and arranged in 25 triplets between 100 and 450 m above the sea floor. The photomultipliers are arranged to look down at 45 ∘ to be sensitive to Cherenkov light from upward going muon tracks produced by extraterrestrial high energy neutrinos traversing the Earth. Such neutrinos arrive undeviated from a variety of astrophysical sources and might be produced in the possible annihilation of dark matter neutralinos. Data from five detection lines in operation since January 2007—and 10 lines since December 2007—are allowing not only a detailed study of detector performance but also the reconstruction of downgoing cosmic ray muons and the search for the first upward going neutrino-induced muons. Constructional details of the telescope are presented and the current status and operations are discussed.