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How to achieve ultra-clean detectors and cryostats at astronomical instruments: measures to avoid contamination and dust on CCD detectors

ESO developed in its detector laboratory a complete routine to achieve ultra-clean detectors with lasting effect with special materials and surface treatments. All components of the detector cryostats are washed in ultrasonic baths, then baked to its maximum temperature in vacuum ovens. As final step plasma cleaning is used of individual and integrated systems. All handlings and the complete integrations are done in the clean room before its integration the detectors are dust cleaned with new methods e.g.: vapor cleaning. At observatory operation the detectors can be monitored by new methods (e.g.: pseudo FF dust evaluation, UV QE test) as a long term contamination control. The always unavoidable moisture in the ready installed instrument can even be cured by UV flashing in dry synthetic air without removing anything from the telescope. Such ESO provides ultra-clean detectors and instruments, which also do not degrade even after years of operation at their telescope sites.