UES Document
Spectral Response Curve for the UES CCD
The pixel size is 22 microns square and the surface has
been coated to enhance the blue response. The rather longish delay in
providing this large format device has been due to the
anomolous dark current we measured (now almost 2 years ago! )
several hundred electrons per hour.
As this is a 2-edge buttable detector, the packaging has meant it was
difficult to secure the device to the cold block and we hence assumed
that this was the cause of the high dark current. I have recently
been involved in some work to 'glue' the chip down onto a piece of
Kovar and this has resulted in a package which can be handled more
easily. The Kovar is secured by 4 retaining screws and we are
confident that this has now ensured that the CCD is making appropriate
contact with the block.. Measurements are under way. The goal we are
seeking is a dark current of around 1-2 e/hour and consistent with
what we measure on other devices of similar type.
We hope to have it on the telescope by Christmas.
Spectral Response of the UES, S/N=A3204-18-11 CCD
Response Curve
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