The ICE board: a Hi-Rel electronics board for sub-nanosecond synchronization of submarine instrumentation

IDMAR, a submarine interdisciplinary laboratory, is being developed off Sicily coast at a depth of 3500 m. The main component of the underwater infrastructure is a node, called Junction Box, that distributes electrical power and fiber optics to underwater user experiments. Inside the Junction Box, a board is dedicated to the management of the underwater instrumentation generally needed for detector calibration and for environmental monitoring. This contribution describes this board and its performance, with a special attention to reliability and timing performance.