Radiation hard sensors for the beam calorimeter of the ILC

The beam calorimeter in the forward region of the ILC detectors will be hit by a large amount of electron-positron pairs originating from beamstrahlung, a new phenomenon at the ILC. The by ionization deposited energy in the BeamCal sensor planes can be as high as 10 MGy per year of operation. The FCAL collaboration investigates different alternatives as possible sensor materials: polycrystalline and single crystal CVD diamond and GaAs. The investigation of these materials includes the measurement of the charge collection distance and the radiation hardness against irradiation with 10 MeV electrons in a test beam to doses of several MGy.