Five new lines for KM3NeT detector placed on the seabed off Sicily

15 April 2021

During a week-long campaign, five new detector lines of the KM3NeT neutrino telescope were installed in the deep sea off Sicily and connected to a new connection box on the seafloor. In total, six detector units are now in operation in the Italian part of KM3NeT.

The ARCA telescope is located in the Mediterranean Sea at a depth of 3,500 meters, about 80 kilometers off the coast of Capo Passero, Sicily, and together with its sister detector ORCA, located off the coast of Toulon, France, will allow scientists to identify the astrophysical sources of high-energy cosmic neutrinos and study the fundamental properties of neutrinos, the most elusive and ubiquitous of the known elementary particles. The two detectors will also provide unprecedented opportunities for Earth and marine science research.

Nikhef is one of the partners in the KM3NeT project in the Mediterranean Sea. Detector globes are being designed and assembled in Amsterdam. Nikhef designer Edward Berbee sailed along last week at the launch of the new lines, from the offshore service ship Miss Marilene Tide.

 

Once complete, the KM3NeT/ARCA detector will form an array of more than two hundred detection units. Each of these 700-m-high structures consists of 18 modules equipped with ultra-sensitive light sensors that record the faint flashes of light generated by neutrino interactions in the pitch-black abyss of the Mediterranean Sea.

During the first part of the operation at sea, a new junction box, a hub for the power distribution and data transmission of the detection units, was added to the infrastructure on the seabed. The junction box is connected by electro-optical cable to the newly renovated INFN laboratory on the mainland in Portopalo di Capo Passero.

In the second part of the operation, five new KM3NeT detection units were deployed, individually connected to the junction box by a remotely operated submarine and deployed in their final vertical configuration. As a final step, the device’s first detection unit, which had already been deployed in 2015, was connected to the new junction box.

A total of six detection units are now in operation, forming the initial core of the neutrino telescope KM3NeT/ARCA. With the six ORCA detection units already collecting data, the KM3NeT neutrino observatory has a sensitivity comparable to its predecessor, the ANTARES neutrino telescope.

KM3NeT is an international collaboration of more than 250 scientists from more than 50 scientific institutions around the world. KM3NeT is included in the list of high priority projects selected by the European Strategy Forum for Research Infrastructures (ESFRI).

Paschal Coyle, spokesperson for the partnership, emphasizes, “The successful installation and operation of multiple ARCA detection units is another important step forward for the KM3NeT project. Now it is full steam ahead with the construction of the hundreds of detection units that will be deployed at the French and Italian sites.’

Berbee calls sailing along with the deployment a true adventure.  ‘After a few teething problems with the new unmanned submarine, two days of hard work proved sufficient to successfully place the five lines on the seabed, unwind them, and put them into operation. This was truly a very special experience.’