Electron Identification Studies for the ATLAS Level 1 Trigger Upgrade

We study options available for achieving an efficient selection of electrons against an overwhelming background of neutral pions at the hardware-based trigger of the ATLAS trigger system. The lateral profiles of electrons and neutral pions are different when the interaction point of the colliding protons is at $z=0$ and an efficient selection is achieved. We show that this efficiency is lost for a more realistic model of the luminous profile of the proton beam. A variable used at the software-based trigger is also shown to be unstable against increasing pileup.