Polarization of silicon detectors by minimum ionizing particles

This work presents quantitative predictions of the properties of highly irradiated (e.g. by high-energy particles, up to an equivalent fluence of 1×1014 n cm−2) silicon detectors operating at cryogenic temperature. It is shown that the exposure to the Minimum Ionising Particle (MIP) with counting rates of about 106 cm−2 s−1 can influence the electric field distribution in the detectorʹs 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 87 K with an infrared (1030 nm) laser to simulate MIPs.