Data Acquisition and Transport for NEMO Project

NEMO collaboration is planning to build an underwater neutrino telescope located South-East off the Sicily coast. This paper will describe the concepts underlying the communication link design going over the whole data acquisition and transport from the front-end electronics, with signal digitization and transmission, to the module gathering four front-end boards and sending data on-shore through a fiber optic link which relies on Dense Wavelength Division Multiplexing. An on-shore board, plugged into a PC, extracts and distributes data both to first-level trigger and control systems. Underwater apparatus monitoring and control is guaranteed by the use of oceanographic instruments and dedicated sensors, whose data are packed and sent back to shore using the same optical link. The communication is fully bidirectional, allowing control information to be exchanged. The architecture described here provides a complete real-time data transport layer between the onshore laboratory and the underwater detector.