Study of characteristics of silicon detectors irradiated with 24 GeV/c protons between −20°C and +20°C

High resistivity ion-implanted silicon pad detectors have been irradiated at +20°C, +10°C, 0°C and −20°C with 24 GeV/c protons at a flux of ∼ 5 × 109cm−2s−1, up to fluences of ∼ 1.1 × 1014cm−2, and maintained at these temperatures during several months after the end of irradiation. The change of the diode reverse current, full depletion voltage and collection efficiency of the charge, deposited by relativistic electrons, are presented as a function of the proton fluence and of annealing time. It is found that operating the detectors below +10°C limits the diode reverse current and the bias voltage necessary to achieve full depletion. Moreover, at these temperatures, the charge collection efficiency for an integration time of 20 ns (typical of LHC operation) is better than 90% for 300 μm detectors irradiated to a fluence of 1014 cm−2 and biased at 160 V.