Development and Testing of WCDA Time Calibration System

The Water Cerenkov Detector Array (WCDA) is an important part of Large High Altitude Air Shower Observatory (LHAASO). The main physical goal is to achieve a survey of the gamma source of the entire northern sky in the very high energy medium and low energy section (100 GeV-30 TeV). In order to ensure the accuracy of the detected radiation source, the detector array needs to be time-calibrated. Therefore, the time calibration method and calibration system construction of the WCDA detector are studied, and the key component-split fiber bundle is tested in batches.