Flashes in the deep

Infrastructure from MacArtney helps scientists look deep into space

Capturing glimpses of particles that can travel through anything is a real challenge. As above-ground telescopes cannot filter out enough/sufficient disturbances to be able to detect neutrinos, they needed to go deep. ANTARES, a collaboration of 30 European universities and research laboratories, designed an underwater telescope array for installation at the bottom of the Mediterranean Sea off the coast of Toulon.

Depths of 2500 metres, however, present their own challenges and through its French subsidiary, EurOceanique, underwater technology experts, MacArtney, helped to design and produce a series of cables and connectors to support the 1000 sensors that make up the underwater telescope.

Underwater telescope array - Copy right Antares


Catching impact flashes at depth

The utter darkness at depths of around 2500 metres is the best place to observe neutrinos. As they travel almost unimpeded through everything, collisions with other atoms are rare. But because trillions of neutrinos pass through the earth every second, there are enough impact flashes to be detected by an array of sensors. These impact flashes can only be detected if all other light sources are filtered out. To catch a glimpse, the ANTARES team needed to construct a large area water Cherenkov detector, an array of photomultiplier sensors on the seafloor 40km off the coast of Toulon.

The large area water Cherenkov detector constructed by the ANTARES Collaboration is made up of an array of approximately 1000 photomultipliers. These are sensors linked by cables in vertical strings anchored to the seabed. The armoured cables needed to be robust enough to withstand the forces at 2½ kilometre depths and reliable for permanent installation.

The electro mechanical cables and mouldings supplied by underwater technology experts, the MacArtney Group through their French subsidiary, EurOceanique, are constructed to endure such depths and forces. 450metre Kevlar armoured connecting cables and penetrators make up each of the 12 strings and connect the photomultiplier sensors that make up the neutrino telescope that is permanently installed off Toulon. The detector is spread over an area of about 40,000 square metres and has a height of around 450 metres.