Simulation of signal in irradiated silicon pixel detectors

Induced currents in silicon pixel detectors of different geometries were simulated. The general properties of charge collection in irradiated segmented devices were investigated. A significant difference in charge collection efficiency (CCE) between n**+-n and p **+-n detectors was predicted after irradiation to the LHC fluences. A possible use of silicon detectors for the LHC upgrade was investigated by simulation of thin pixel sensors. The reduced CCE due to charge trapping seems to be the largest obstacle for their use.