Space Telescope Science Institute   4.2.3 Quantum Efficiency Hysteresis  4.2.5 Readout Format

4.2.4 CCD Long-Wavelength Fringing


Like most thinned CCDs, the ACS CCDs exhibit fringing in the red, longward of ~7500 Å. The amplitude of the fringes is a strong function of wavelength and spectral resolution. The fringe pattern can be corrected by rectification with an appropriate flat field. The fringe pattern is a convolution of the contours of constant distance between the front and back surfaces of the CCD, and the wavelength of light on a particular part of the CCD. The fringe pattern has been shown to be very stable in similar devices, as long as the wavelength of light on a particular part of the CCD stays constant. In practice, this means that the fringe pattern is dependent on the spectrum of the light incident on the detector, with the sensitivity to the source spectrum a function of the bandwidth of the filter.


 4.2.3 Quantum Efficiency Hysteresis  4.2.5 Readout Format
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