Monitoring and Data Quality assessments for the ATLAS Liquid Argon Calorimeter at the LHC

The ATLAS detector at the Large Hadron Collider is expected to collect an unprecedented wealth of data at a completely new energy scale. In particular its Liquid Argon (LAr) electromagnetic and hadronic calorimeters will play an essential role in measuring final states with electrons and photons and in contributing to the measurement of jets and missing transverse energy. The ATLAS LAr calorimeter is a system of three sampling calorimeters (electromagnetic barrel, hadronic endcaps and forward calorimeters) with LAr as sensitive medium. It is composed by 182,468 readout channels and covers a pseudo-rapidity region up to 4.9. Efficient monitoring will be crucial from the earliest data taking onward and at multiple levels of the electronic readout and triggering systems. Detection of serious data integrity issues along the read-out chain during data taking will be essential so that quick actions can be taken. Moreover, by providing essential information about the performance of each sub-detector, the quality of the data collected (hot or dead channels, alignment and calibration problems, timing problems...) and their impact on physics measurable, the monitoring will be critical in guaranteeing that data is ready for physics analysis in due time. Software tools and criteria for monitoring the LAr data during the cosmic muon runs, which have been taking place since October 2006, are discussed. The further extension to the strategy f or monitoring collisions data expected for the end of year 2009 is also described.