Sub-nanosecond synchronization node for high-energy astrophysics: The KM3NeT White Rabbit Node

Abstract The first Detection Units of the KM3NeTinfrastructure, whose main goal is the detection of cosmic neutrinos, are currently being deployed on the Mediterranean Seabed. The collaboration has chosen WhiteRabbit for providing sub-nanosecond synchronization between the Digital Optical Modules, the main detection component of the detector. WhiteRabbit functionality is provided by the main front-end electronics board, the so called Central Logic Board, that embeds both the WhiteRabbit firmware, as an IP core on a XILINX Kintex FPGA, and the tunable oscillators, the hardware needed to make WhiteRabbit to work. The present article describes the Central Logic Board of KM3NeT, focusing on how it provides WhiteRabbit functionalities.