Noise sensitivity to gamma radiation in Si-jfet devices

The result of noise measurements for a Charge Sensitive Preamplifier based on Si-Field Effect Transistor exposed to a total Gamma ray dose of 30 v Mrad have been reported. The radiation effect on the DC parameters of single transistors was also tested. Our study has shown that, there are no changes on the DC parameters. Meanwhile the noise level, which was evaluated by the total equivalent noise charge, was clearly increased. The results of noise measurements were analyzed and compared with theoretical predictions. The temperature and time-dependent effects on the noise had also been reported after irradiation. All measurements were performed for biased and unbiased irradiated transistors.