for a Si CID damaged incrementally by 12 MeV protons. The increase over the pre- irradiation dark current is determined for each pixel and the three histograms are formed from the 61,504 pixel population following each exposure. The high dark current tail is produced from single-particle inelastic nuclear reactions that deposit large amounts of displacement damage energy within the pixel, but are rare enough that relatively few pixels are affected at low fluences. Marshall et al. [Mars89b, Mars90] and Dale et al. [Dale89b, Dale90, Dale94] have studied the statistics of dark current fluctuations in detail and developed quantitative descriptions of the effect. As seen in figure 19, the analytic predictions (solid lines) of the dark current distributions [Mars90] agree well with the experimental results. At higher proton energies, where the primary recoil ranges approach the pixel dimensions, Monte Carlo techniques are required to model the dark current distributions [Dale94]. In some devices, the presence of even very small high electric field regions can result in dark current distributions that are significantly more skewed than those seen in figure 19 [Srou89, Mars89b, Mars90, Dale90, Hopk92]. Improved device design and a reduction of the applied biases can greatly minimize the occurrence of these very high dark current pixels. The high dark current pixels (so-called spikes) have been observed by several groups in a variety of devices, and also have been noted to have an erratic time dependence [e.g., Srou86, Hopk89, Mars90, Mill94, Dai96]. Hopkins and Hopkinson IV-86 showed that the dark current within a single pixel not only fluctuates in time, but also switches between well-defined levels and has the characteristics of random telegraph noise [Hopk92, Hopk93, Hopk95]. This behavior is illustrated in figure 20 for an EEV CCD irradiated by 10 MeV protons. This type of noise represents a significant calibration problem for some applications. EEV CCD05, 10 MeV Protons Time (Hours) Figure 20 After the proton irradi