Commissioning of ATLAS Data Quality Infrastructure with First Collision Data

During particle physics data taking, the data being recorded must be monitored and checked continuously and promptly. The data quality system of the ATLAS experiment at the Large Hadron Collider provides the means to investigate and monitor the data recorded. Over the course of 2010, this system has been commissioned successfully with first collision data. Data quality monitoring enables prompt investigation of the first pass of full event processing at the Tier-0 CERN computing centre, the validation of calibration and other reconstruction parameters, and any detector issues to be diagnosed and, wherever possible, fixed. Automatically filled histograms are checked by algorithms and against references, the results of which are stored as status flags in a database, and published onto a web server, where they can be inspected by shifters and experts. The data quality for approximately 100 data quality regions is determined, and propagated in a convenient format for data analysis teams.