The ATLAS Trigger and Data Acquisition System during the 2002 combined testbeam run

The Trigger and Data Acquisition System of the ATLAS experiment at CERN has undergone a series of design and prototyping phases, with the aim of studying different architectural and technological choices suited to sustaining the very high event rate and data size of this experiment: up to 100 kHz Level 1 trigger accept rate, with events of the order of 2 MB. The DAQ/EF-1 project, a vertical slice of the Data AcQuisition and Event Filter, is one of these prototypes. After the completion of its development and implementation, this prototype was reengineered for exploitation as a DAQ system for the ATLAS detectors in testing and calibration phase. During summer 2002 DAQ/EF-1 has been successfully integrated with several detectors. This paper presents an overview of DAQ/EF-1 the implementation of a PC based setup that has been prepared for the combined testbeam of the Pixel, the tile calorimeter and the MDT detectors, and the usage of the Event Filter during data taking. (7 refs).