Radiation hardness of CCD vertex detectors for the ILC

Results of detailed simulations of the charge transfer inefficiency of a prototype CCD chip are reported. The effect of radiation damage in a particle detector operating at the ILC is studied for two electron trap levels, 0.17 eV and 0.44 eV below the conduction band. Good agreement is found between simulations and an analytical model for the 0.17 eV level. Optimum operation is at about 250 K, approximately independent of readout frequency.