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21 February 2003 Low readout noise CCDs in optical interferometry
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Most current CCDs cannot be used as optical interferometric sensors because the high readout noise disguises the small signal. However, new low light level charge coupled devices (L3CCD) have a large on-chip gain which can allow a signal to be detected above the noisy readout amplifier. This gain has a statistical nature, meaning that the photon input cannot be predicted exactly. We investigate several techniques for photon prediction at different light levels, and demonstrate how this affects the noise on the signal. Accurate signal estimation can be achieved with very faint signals, up to about one photon per pixel per read. Above this, accuracy gradually decreases, though our signal-to-noise ratio is never worse than square root(2n). Optical interferometry requires detection of very faint signals, and the use of an L3CCD is found to allow reproduction of interferometric visibilities to high precision. Custom instrumentation used for control is also detailed.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Alastair G. Basden, David F. Buscher, Christopher A. Haniff, and Craig D. Mackay "Low readout noise CCDs in optical interferometry", Proc. SPIE 4838, Interferometry for Optical Astronomy II, (21 February 2003);

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