Commissioning of the ATLAS Electron and Photon Trigger Selection

This talk gives an overview of the calorimeter based performance of the electron and photon trigger selection in the first 7 TeV collisions data collected by ATLAS at the beginning of 2010. Data selected by the hardware based Level-1 trigger was processed online by the software based Level-2 and Event Filter which were mainly running without active rejection. Examples of comparisons of the three trigger levels with the offline reconstruction will be presented, such at the Level-1 turn-on and the distributions of the calorimeter based selection variables used to distinguish between signal and background. This is an important step in the commissioning of these triggers to ensure their correct functioning. Furthermore, examples of comparisons between data and simulations of some of the selection variables will be presented. At the end of the talk a brief outlook will be given of the steps to be taken to fully commission these trigger and on the strategy how the e/g menu will evolve with increasing luminosities.