KM3NeT
KM3NeT (the name is derived from "cubic kilometer neutrino telescope") is a large submarine instrument that has been under construction since the end of 2015 for the detection of neutrinos of cosmic origin. The neutrino telescope consists of a Cherenkov detector with an instrumented volume of around five cubic kilometers, which is distributed over three locations in the Mediterranean: KM3NeT-Fr (off Toulon , France), KM3NeT-It (off Portopalo di Capo Passero , Sicily, Italy) and KM3NeT-Gr (off Pylos , Peloponnese, Greece).
KM3NeT will search for neutrinos from distant astrophysical sources such as supernova remnants, gamma ray bursts , supernovae or colliding stars and will be a powerful tool in the search for dark matter in the universe. Its main goal is to discover neutrinos from sources in our galaxy . Arrays made up of thousands of optical sensor modules will detect the weak light from charged particles in the deep sea, resulting from the collisions of neutrinos with matter near the detector. The research infrastructure will also include instruments for other sciences such as marine biology, oceanography and geophysics to monitor the deep-sea environment and the seabed at a depth of several kilometers over the long term and online.
Upon completion, the KM3NeT research infrastructure will consist of seven large sub-detectors. Six of these will form the actual telescope in the search for neutrino sources. The seventh sub-detector is optimized to measure the properties of the neutrino itself. In this sense, the latter detector is a neutrino particle physics detector.
design
The complete neutrino telescope will contain around 12,000 pressure-resistant glass spheres attached to around 600 strands. The strands each contain 18 sensor spheres that are anchored to the sea floor and carried by floating bodies. Each sphere, known as a "digital optical module" (DOM), has a diameter of about 43 cm, contains 31 7.6 cm photomultiplier tubes with supporting electronics and communicates with high bandwidth using an optical network.
On the bank of each KM3NeT installation site, a computer farm performs the first data filter when searching for signals from cosmic neutrinos before the data is streamed to a central KM3NeT data center for storage and further analysis by the KM3NeT scientists.
The KM3NeT-IT system at a depth of 3400 m houses the ARCA detector with widely spaced DOMs that are optimized for the detection of high-energy cosmic neutrinos in the TeV-PeV range. Its strands are 650 m long and 90 m apart.
The French KM3NeT site at a depth of 2,475 m houses the ORCA detector, a more compact arrangement with narrow sensors that are optimized for atmospheric neutrinos in the GeV range. This consists of 115 strings in a 20 m triangular grid with a distance of 9 m between the DOMs on one strand. Overall, the array has a diameter of about 210 m and the strands are 200 m long.
construction
In 2012, the first phase of implementation of the KM3NeT research facility began with the construction of the seabed infrastructure at the KM3NeT-Fr and KM3NeT-It locations. A prototype of the KM3NeT Digital Optical Module (KM3NeT-DOM) has been successfully recording data from the ANTARES telescope for over a year . The KM3NeT-Fr installation site near the ANTARES telescope is being prepared for the installation of the first strings for the KM3NeT / ORCA detector for neutrino particle physics. At the KM3NET Italian site, the first KM3NeT prototyping string successfully recorded data for about a year. This page is being prepared for the installation of the first full strings from the end of 2015.