The Cosmic Electron Background in Low Energy IACTs. Effect of the   Geomagnetic Field
  A new generation of low threshold Imaging Atmospheric Cherenkov Telescopes (IACTs) may reach gamma-ray energies about 10 GeV with high sensitivities and very large collection areas. At these low energies cosmic electrons significantly contribute to the telescope background and are in principle indistinguishable from gamma-rays. In this paper we estimate the electron background expected for two configurations of the low energy IACT MAGIC. We discuss in particular the reduction of the background caused by the geomagnetic field at different locations on the Earth's surface. 
J. Cortina, J. C. Gonzalez (MPI fuer Physik, Munich, Germany)