Integration of the Trigger and Data Acquisition Systems in ATLAS

During 2006 and spring 2007, integration and commissioning of trigger and data acquisition (TDAQ) equipment in the ATLAS experimental area has progressed. Much of the work has focused on a final prototype setup consisting of around eighty computers representing a subset of the full TDAQ system. There have been a series of technical runs using this setup. Various tests have been run including those where around 6 k Level-1 preselected simulated proton–proton events have been processed in a loop mode through the trigger and dataflow chains. The system included the readout buffers containing the events, event building, second level and third level trigger processors. Aspects critical for the final system, such as event processing times, have been studied using different trigger algorithms as well as the different dataflow components.