KM3NeT, an acronym for Cubic Kilometre Neutrino Telescope, is a future European research infrastructure which will be located at the bottom of the Mediterranean Sea. It will host a neutrino telescope in the form of a water Cherenkov detector with a volume of at least one cubic kilometre.
KM3NeT will search for neutrinos from distant astrophysical sources like gamma-ray bursts, supernovae or colliding stars and will be a powerful tool in the search for dark matter in the universe. An array of thousands of optical sensors will detect the faint light in the deep sea from charged particles originating from collisions of the neutrinos and the Earth. The facility will also house instrumentation from other sciences like marine biology and geophysics for long term and on-line monitoring of the deep sea environment and the sea bottom at depth of several kilometres.
In February 2006, a three-year design study of the infrastructure started with the objective to define the technology required to build it. This design study ended 31 October 2009. The deliverable of the study will be a Technical Design Report (TDR) which will be made public early 2010.
For the design of the neutrino detector, KM3NeT builds on the experience of three pilot projects in the Mediterranean Sea: the ANTARES detector, the NEMO experiment and the NESTOR Project. ANTARES was completed on 30 May 2008, and is the largest neutrino telescope in the northern hemisphere. It consists of twelve strings (vertical cables) with 900 photomultiplier tubes attached. The lines are anchored at the sea bottom at a depth of 2.5 kilometres (1.6 mi) and are about 70 metres (230 ft) apart from each other. The relative position of the photomultiplier tubes in the sea are monitored with an acoustic positioning system. The NEMO and NESTOR projects each have chosen a different approach: they have designed rigid structures, named towers, to support the array of photomultipliers. The choice between the three different designs is part of the KM3NeT design study.
It is expected that KM3NeT will house in the order of 10,000 optical modules, which can be distributed in many ways in the detector volume. The choice for the best configuration is part of the KM3NeT design study.
In the southern hemisphere, at Antarctica, the IceCube Neutrino Observatory is under construction, with a completion date of 2011. Together, IceCube and KM3NeT will view the full sky.