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Paper: Non-linear pixels in the USNO Tektronix 2048 X 2048 CCD
Volume: 8, CCDs in Astronomy
Page: 53
Authors: Levison, Harold F.
Abstract: Approximately 4.4 percent of the pixels on the USNO Tektronix 2048 x 2048 CCD are nonlinear. These nonlinearities can be fit by analytic functions in two regimes. When I(exp) is less than about 400 ADU, the bad pixels are fit by I(obs)/I(exp) = 1 - fe exp gIobs. For I(exp) of more than about 600 ADU, I(exp) = aI(obs) exp b is used. Unfortunately, it was not possible to find an analytic function that fit all pixels between these two regimes. since the CCD must be preflashed to remove charge transfer inefficiencies, it is only necessary to fit the nonlinearities at high charge levels. Using the second fitting function, it was possible to correct 93 percent of the bad pixels over approximately 2 orders of magnitude in the illumination.
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