|WEBHMULT04||Sub-nanosecond Timing System Design and Development for LHAASO Project||646|
Funding: National Science Foundation of China (No.11005065)
The Large High Altitude Air Shower Observatory (LHAASO)  project is designed to trace galactic cosmic ray sources by approximately 10,000 different types of ground air shower detectors. Reconstruction of cosmic ray arrival directions requires sub-nanosecond time synchronization, a novel design of the LHAASO timing system by means of packet-based frequency distribution and time synchronization over Ethernet is proposed. The White Rabbit Protocol (WR)  is applied as the infrastructure of the timing system, which implements a distributed adaptive phase tracking technology based on Synchronous Ethernet to lock all local clocks, and a real time delay calibration method based on the Precision Time Protocol to keep all local time synchronized within a nanosecond. We also demonstrate the development and test status on prototype WR switches and nodes.
 Cao Zhen, "A future project at tibet: the large high altitude air shower observatory (LHAASO)", Chinese Phys. C 34 249,2010
 P. Moreira, et al, "White Rabbit: Sub-Nanosecond Timing Distribution over Ethernet", ISPCS 2009
|Slides WEBHMULT04 [8.775 MB]|