Km3net

KM3NeT is a future European research infrastructure which will be located at the bottom of the Mediterranean Sea. It is an acronym for cubic kilometer size (KM3) Neutrino Telescope.

It will host a neutrino telescope in the form of a water Cherenkov detector with a volume of at least one cubic kilometre. KM3NeT (KM3NeT stands for km³ NEutrino Telescope) 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 kilometers.

In February 2006 a 3-year design study of the infrastructure started with the objective to define the technology required to build it.

For the design of the neutrino detector, KM3NeT builds on the experience of three pilot projects in the Mediterranean Sea: the Antares telescope, the NEMO telescope and the Nestor telescope. The Antares neutrino telescope has been completed May 30th, 2008. It is the largest neutrino telescope in the Northern hemisphere and consist of twelve strings - vertical cables with in total 900 photomultiplier tubes attached to it. The lines are anchored at the sea bottom at a depth of 2.5 km, about 70 m 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.

The picture shows an artists view of a possible configuration of the large array of optical modules - pressure resistive glass spheres containing the photomultipliers. It is expected that KM3NeT will house in the order of 10000 optical modules, which can be distributed in many ways in the detector volume. The choice for the most optimal configuration is part of the KM3NeT design study.

At the southern hemispere of the Earth, at Antarctica, the IceCube neutrino telescope is being built already. Together, IceCube and KM3NeT will view the full sky.

References

[http://www.km3net.org/ KM3NeT Homepage]

[http://icecube.wisc.edu IceCube Homepage]

[http://antares.in2p3.fr Antares home page]

[http://nemoweb.lns.infn.it NEMO home page]

[http://www.nestor.org.gr Nestor Homepage]