The underwater power and communications hub of the ANTARES neutrino telescope

The ANTARES deep sea neutrino telescope, under construction off the French Mediterranean coast, will contain 900 photomultiplier tubes arranged along 12 moored detection lines. The detector is powered and read out via an underwater junction box hub and a telecommunications cable linking the site to the shore station. The junction box contains the power delivery and management system and the fibreoptic routing for all the clock and data signals for the detector. Power distribution is based on a transformer with 18 independent secondary windings. Electrical energy in the range 3700 to 4100 V AC from the shore station is transformed from 435 to 480 V AC to power the detection lines and from 200 to 230 V for the junction box slow control electronics. An external plugboard of deep sea-mateable electro-optic connectors allows the connection of up to sixteen detection lines or oceanographic packages using manned or remotely operated submersible vehicles. The triply-redundant power management and slow control system of the junction box is based on two distinct technologies; two identical systems powered from the internal transformer communicate with the shore through fibreoptic 160 Mb/s G-links while a third battery-powered system communicates through a low power, low speed link. We describe the power and slow control systems of the underwater junction box hub. Data from nearly three years' continuous operation of the slow control system are also presented.