Radiation effects on the Viking-2 preamplifier-readout chip

We have studied the radiation sensitivity of the Viking-2 VLSI circuit which has been designed for the readout of silicon strip detectors and manufactured at Mietec in 1.5 μm CMOS technology. Both biased and unbiased chips have been irradiated with a 137Cs γ source up to a total dose of 2 kGy (200 krad) after which all tested chips were still fully functional. We report the characteristic changes of device parameters with dose, including equivalent noise charge for different capacitive loads, and determine transistor threshold shifts and change of mobilities.