Development of a New Laser Beacon for Time Calibration in the ANTARES Neutrino Telescope

The ANTARES collaboration has built a deep sea neutrino telescope in the Mediterranean Sea consisting of a matrix of pressure resistant glass spheres holding large area photomultipliers. The aim of the telescope is to observe cosmic neutrinos through the Cerenkov light induced in sea water by charged particles produced in neutrino interactions with the surrounding medium. A relative time calibration between photomultipliers of the order of 1 ns is required to achieve an optimal performance. To this end, several time calibration subsystems have been developed for the whole telescope. In this article, the design, tests and integration of the last Laser Beacon model, developed to measure and monitor the relative time offsets between photomultipliers, are described.