Prototype of White Rabbit network in LHAASO

Synchronization is a crucial concern in distributed measurement and control systems. White Rabbit provides sub-nanosecond accuracy and picoseconds precision for large distributed systems. In the Large High Altitude Air Shower Observatory project, to guarantee the angular resolution of reconstructed air shower event, a 500 ps overall synchronization precision must be achieved among thousands of detectors. A small prototype built at Yangbajin, Tibet, China has been working well for a whole year. A portable calibration node directly synced with the grandmaster switch and a simple detectors stack named Telescope are used to verify the overall synchronization precision of the whole prototype. The preliminary experiment results show that the long term synchronization of the White-Rabbit network is promising and 500 ps overall synchronization precision is achievable with node by node calibration and temperature correction. (author)