Portable Calibration Node for LHAASO-KM2A Detector Array

Aiming to high sensitivity and wide spectrum of cosmic ray detection, the 1 km
²
complex array of large high altitude air shower observatory (LHAASO-KM2A) project consists of over 7000 detectors of different types. To reconstruct the air shower events with high angular resolution, timestamps of all detector electronics and digitizers should be aligned better than 500 ps RMS. White Rabbit (WR) technology, a fully deterministic Ethernet-based network with subnanosecond synchronization accuracy and picoseconds precision, is applied to build the dedicated data and timing network. To guarantee the overall synchronization precision, individual calibration of each WR node is essential to compensate device deviation. This paper talks about autocalibration procedure of all nodes in the LHAASO-KM2A WR network using the portable calibration node (PCN). Usage of the PCN in deploying the detectors array and validating synchronization performance of the WR network is also discussed.