DAQ architecture design of Daya Bay Reactor Neutrino Experiment

The main task of the data acquisition (DAQ) system in Daya Bay Reactor Neutrino Experiment is to record antineutrino candidate events and other background events. There are seventeen detectors in three sites. Each detector will have a separate VME readout crate that contains the trigger and DAQ electronics modules. The DAQ system reads event data from front end electronics modules, concatenates data fragments of the modules and packs them to a subsystem event, then transmits to the backend system to do data stream merging, monitoring and recording. The DAQ architecture design is a multi-level system using advanced commercial computers and the network technology. The architecture requires multiple independent or part joint DAQ systems at each site. The run control will be configurable and flexible; it should allow both global operation of all detector systems in all three sites, and operations of parts of detectors whenever debugging or commissioning is required. The system should allow each subsystem in any detector site to start its own run control so that debugging and commissioning can be conducted in parallel. This paper presents the main DAQ design requirements, the system architecture design and the software architecture design.