Single and multiple proton-induced NIEL events in silicon

Computer simulations of proton-induced spallation reactions predict the deposition of as much as 200 KeV of non ionizing energy loss (NIEL) within the active regions of CCD pixels as the result of individual spallation reactions. Peaks in the NIEL-deposition spectra at low fluence correspond to the recoils of different nuclear fragment isotopes. The increase in pixel dark current from such events is a design constraint for the use of CCDs in satellite communications, hyperspectral imaging and other applications which require low-noise imaging. Individual pixels can be functionally impaired by single-event NIEL. At high fluence, the spallation reactions will be responsible for at least half the increased pixel noise and dominate the shape of the measured noise spectra. Calculations show good agreement with available measurements.<
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