CCD-world: Need help - Cleaning of contaminated CCD surface boundary="------------B8D053A34C37B0889F5C8376"

[Byeong-Gon Park (¹Úº´°ï)]

Dear Gurus;

Is anybody there who has experience to clean
a contaminated CCD surface?

I have a TK1024 chip whose surface is covered by
thousands of liquid drops. The situation is as the following.

When we evacuate our camera dewar which was attached at the
telescope with LN2 filled, the pump accidentally stopped
by unknown cause. Our pump is turbo molecular pump of Balzers.

Later, when I looked the CCD surface through quartz window,
I found strange patterns there. Under microscope it looked
so many liquid drops. At first I guessed they were water drops
frosted on the surface, so put the CCD into an oven and baked
at 60C for 6 hours. There was no change. The liquid might be
oil drops rather than water. But I don't understand how the oil
in the rotary pump could run back to the dewar in this type
of vacuum pump. My pump is full-automatic, that is, I just
push a start button to on/off the system and the security
system did not show any problem after the accident.

Any way, I have to clean this contaminated CCD and need
help from those who out there.

Thanks,
Byeong-Gon

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