This note describes a study of the possibilities for selecting an electron
calibration stream using the High level electron trigger (Level 2 and the event
filter). Using the electromagnetic calorimeter reconstruction and the track
reconstruction algorithms, an evaluation has been performed of the selection
efficiencies and purities for different physics channels with single or double
electrons in the final state. A study of the calibration stream composition,
including the background from QCD processes, is presented.Comment: 14 page