Measured performance of the prototype polar coordinate CCD array

This paper describes the design and testing of a prototype high frame rate CCD imager called the polar coordinate detector developed as part of a project led by the W. M. Keck Observatory (WMKO) and funded by the Adaptive Optics Development Program and the Thirty Meter Telescope (TMT) Project. The polar coordinate detector is designed to address the problem of adaptive optics (AO) laser guide star (LGS) spot image elongation in Shack Hartmann wavefront sensors for extremely large telescopes. The prototype detector, designated the CCID-61, was developed in collaboration with the MIT Lincoln Laboratory. The CCID-61 implements a detector for one quadrant (30 x 30 subapertures) of the planned 60 x 60 subaperture LGS wavefront sensors of the TMT early light AO system NFIRAOS. Testing of front illuminated, packaged detectors has been completed and performance results including read noise, readout speed, charge diffusion, and dark current are reported.