KM3NeT

Infrastructure and User Services

The infrastructure consists of three so-called building blocks. A building block is comprised of 115 strings, each string has 18 optical modules module with 31 photo-multiplier tubes (PMTs). This 3-dimensional array of photo-sensors allows for the detection of the Cherenkov light produced by relativistic particles emerging from neutrino interactions. Two building blocks will be configured to fully explore cosmic neutrino sources (ARCA: Astroparticle Research with Cosmics in the Abyss). One building block will be configured to measure precisely atmospheric neutrino oscillations (ORCA: Oscillations Research with Cosmics in the Abyss). ARCA will be realised at the Capo Passero site (Italy) and ORCA at the Toulon site (France). The technical implementation of ARCA and ORCA is almost identical. The deep-sea sites are linked to shore with a network of cables for electrical power and high-bandwidth fibre-optic communication. On site, shore stations provide power, computing and high-bandwidth connections to central data repositories. The flexible and cost-effective detector design has major Dutch intellectual and technical contributions.
The collaboration has opted for a phased implementation of KM3NeT. Phase-1 included a validation programme, partial construction of the sea-floor networks and the installation of 31 strings. Currently 57 strings are deployed (24 ORCA, 33 ARCA). Data taking is ongoing and several physics results were already obtained. The data includes recorded optical data (precisely-timed hits in the PMTs), acoustic data and environmental data such as water temperature and Sea current. Apart from calibration periods, data taking proceeds on a 24/7 basis. All data is sent to the shore stations, where it is filtered for interesting events.
 

Examples/description of the type of research

The research infrastructure will be ideally suited for the discovery and subsequent observations of the sources of high-energy neutrinos in the Universe. KM3NeT offers hereby a unique view of the center region of the Galactic plane and with this an opportunity especially for the study of galactic sources. The observations will complement existing astronomical observations and allow to solve the question about the so far still unknown origin of very high energy cosmic rays. They will bring new insights about the astrophysical processes inside cosmic accelerators.

The abundant observations of neutrinos created in the Earth’s atmosphere will allow to study neutrinos themselves and to determine relevant fundamental properties like the still unknown mass ordering of neutrinos or the parameters governing the phenomenon of neutrino oscillations. This will advance our understanding of  the fundamental objects in the current standard model of particle physics and can also contribute to unravelling the so far unknown nature of dark matter. The data also allow to probe various different new physics scenarios.

The abundant observations of muons from cosmic ray interactions in the atmosphere also enable contributions to cosmic ray science, probing the composition of cosmic rays and bringing new information on fundamental particle interactions at very high energies unreachable in Earthbound accelerators.

KM3NeT also offers interdisciplinary opportunities for continuous, real-time measurements, in the Mediterranean of optical and acoustic data as well as Sea current and temperature, which are useful also for marine biology, oceanography or environmental sciences.
 

How to access the infrastructure?

1. Data access: data is processed to make them meaningful for the users. Data access is exclusive to members of the Collaboration for a certain embargo period.
2. Access to user ports: earth and sea scientists (and others) will have the opportunity to connect their devices to the user ports.
3. Observation time: New or additional filter algorithms (“observation filters”) are implemented to search for neutrinos from e.g. specific astrophysical sources.
4. Alert networks: A network system has been established. KM3NeT will provide alerts for other nodes of this system and will receive and follow up alerts by these nodes