  Two different technologies are considered for the Beam Calorimeters of the
ILC detector. Simulation studies of the performance have been done for a
diamond-tungsten sandwich calorimeter and for a homogeneous heavy element
crystal calorimeter with optical fiber readout. Studies of the stability and
the linearity of a polycrystalline diamond were done for the diamond-tungsten
option. For the heavy crystal option the light yield reduction due to the
wavelength shifting fiber readout was studied.
