Prompt Calibration, Assessment of Data Quality and Data Processing

All data collected by the ATLAS experiment are processed "promptly" at the CERN Tier0 to provide fast access to high quality data for physics analyses. The high quality of the data is achieved by a so-called "calibration loop" that relies on the detector calibrations to become available on a time scale of 36 hours based on a selected subset of the data designed to allow detailed data investigations. Based on these data new calibrations and updated lists of dead or hot channels are created and those calibrations and/or lists of masked channels are created. These are then used for the so-called "bulk processing" which is the main processing for the physics streams. In 2010 this model was implemented in mid April and was successfully applied throughout the year, and indeed the quality of the data was sufficiently high so that many physics publications were based on this initial Tier0 processing.