MIT/Lincoln Labs CCID20 W94C1 CCD Test Results

This phase 2 MIT/Lincoln Labs 2Kx4K CCD has more problems than many CCID20s. A summary report is available. Noteworthy points about this CCD include:

• Bad "brickwall" pattern. We're calling this the type-3 brickwall.
• Lower than normal serial CTE (0.999948).
• Some very hot columns.

Original postscript files are available from our anonymous ftp server and these provide better resolution and clarity than is usually possible on a web page. Here are a few figures to illustrate device highlights:

"Brick wall" resulting in poor QE
The brick wall pattern on this device is much worse than most and has a characteristic pattern we call type-3. As detailed in the report and shown in this image, peak-to-valley variations are very large.
Serial CTE
CTE measurements show lower than normal serial CTE.

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This graph shows the QE variations caused by the brick wall pattern. QE was measured at the peak and in the valley of the brick wall as well as over a large area to obtain an average QE.

Serial CTE as measured with Fe⁵⁵ is show here. Readout was through the left or B amplifier. CTE was about 0.999948 per pixel. As this plot shows, about 10% of the charge is left behind after 2048 transfers. Parallel CTE was much better, at about 0.999985 per pixel, or 6% loss after 4096 transfers.

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