This work presents quantitative predictions of the properties of highly irradiated (e.g. by high-energy particles, up to an equivalent fluence of 1x10 1 4 ncm - 2 ) silicon detectors operating at cryogenic temperature. It is shown that the exposure to the Minimum Ionising Particle (MIP) with counting rates of about 10 6 cm - 2 s - 1 can influence the electric field distribution in the detector's sensitive volume. This change in the electric field distribution and its effect on the charge collection efficiency are discussed in the frame of a model based on trapping of carriers generated by MIPs. The experiment was performed at 87K with an infrared (1030nm) laser to simulate MIPs.