Dose Rate and Bias Effects on COTS Array CCDs Induce Dark Signals Increase

The experiments of dose rate and bias effects on commercial-off-the-shelf array charge-coupled devices (CCDs) are presented. The dark signal (V-D) is calculated with the output signal voltages measured at different integration times when no light is incident on the CCDs. The dark signal voltages (V-D) versus the total dose at the dose rates of 0.01, 0.1, 1.0, 10.0, and 50 rad(Si)/s are compared. Annealing tests are performed to eliminate the time-dependent effects. Degradation levels were found to depend on the dose rates. The CCDs are divided into two groups-with one group biased and the other unbiased during Co-60 gamma irradiation. The biased CCDs are shown to degrade more severely than the unbiased CCDs.