GIRAFFE CCD Decontamination April 2005During April 2005, on the FLAMES-GIRAFFE CCD a decontamination procedure was executed. This consisted in warming up the CCD to ambient temperature so to get rid of dirt that had collected on the surface of the CCD.
You can see here a flat field taken just before decontamination . The black area is obut 4000 counts below the surrounding area.
After the procudere took place, the CCD went back to almost normal performances. Here is a flat after decontamination . The black region is now less than 1000 counts below the surrounding area.
After about a week the CCD recovered full operational capability. Here you can see the flat field of the fully recovered CCD.