Inter-Calibration of the CMS Electromagnetic Calorimeter with Isolated Electrons

The CMS electromagnetic crystal calorimeter must be precisely inter-calibrated if its full potential performance is to be realized. In this note we describe a detailed Monte Carlo study of in-situ inter-calibration of the ECAL crystals using isolated electrons. The achievable precision depends on the quality and number of available electrons per crystal. This in turn depends upon the position of the crystals and the corresponding thickness of material in front of the ECAL.