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15 September 2004 Optimization of SDSU-2 CCD controller hardware and software for CCD mosaics
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The San Diego State University Generation 2 CCD controller (SDSU-2) architecture is widely used in both optical and infrared astronomical instruments. This architecture was employed in the CCD controllers for the DEIMOS instrument commissioned on Keck-II in June 2002. In 2004, the CCD dewar in the HIRES instrument on Keck-I will be upgraded to a 3 x 1 mosaic of MIT/LL 2K x 4K CCDs controlled by an SDSU-2 CCD controller. For each of these SDSU-2 CCD controllers, customized versions of PAL chips were developed to extend the capabilities of this controller architecture. For both mosaics, a custom timing board PAL enables rapid, software-selectable switching between dual- and single-amplifier-per-CCD readout modes while reducing excess utilization of fiber optic bandwidth for the latter. For the HIRES CCD mosaic, a custom PAL for the clock generation boards provides software selection of different clock waveforms that can address the CCDs of the mosaic either individually or globally, without any need to reset the address jumpers on these boards. The custom PAL for the clock generation boards enables a method for providing differing exposure times on each CCD of the mosaic. These distinct exposure times can be implemented in terms of a series of sub-exposures within a single, global mosaic observation. This allows for more effective observing of sources that have flux gradients across the spectral dimension of the CCD mosaic because those CCDs located near the higher end of the flux gradient can be read out more frequently, thus reducing the number of cosmic rays in each individual sub-exposure from those CCDs.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Robert I. Kibrick, Chris Wright, Steven L. Allen, and De A. Clarke "Optimization of SDSU-2 CCD controller hardware and software for CCD mosaics", Proc. SPIE 5496, Advanced Software, Control, and Communication Systems for Astronomy, (15 September 2004);


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