Speaker
Description
Spurious charge (SC), generated by the clocking of the gate phases, is a dominant noise source in single-electron-resolution CCDs and a critical parameter for the next generation of low-noise astronomical detectors. We present a systematic experimental study of SC in the multiple-amplifier sensing CCD (MAS-CCD), characterizing its dependence on the horizontal-clock voltages, the pixel readout time, the number of charge transfers, and the physical region of the sensor. Using a covariance-based technique that leverages the MAS architecture to measure SC directly from standard readout images, we disentangle the SC generated in the active serial register from that generated in the extended register between amplifiers. We find that the MAS extended-register contribution is small, which supports extending the number of in-line amplifiers without degrading performance. Among the operating parameters, the voltage swing and the number of transfers both affect SC, but the time the charge spends under the clock gates is the dominant factor—motivating faster readout schemes to minimize SC. Using a a set of purpose-built clocking sequences, we further identify localized generation sites along the active region, visible as hot columns, and characterize their temporal behavior as a step toward resolving the underlying trap time constants that could explain SC generation. These results establish a practical framework for fast, systematic SC characterization and inform the design of MAS-CCD sensors for future ground- and space-based spectroscopic instruments.