Introduction

The emergence of contamination on CCD detectors during their operational phase is a problem known to several observatories. In some cases, finger grease or gloves used during assembly were found to be the origin of these deposits on the chip, but mechanical or electronical components with highly volatile substances are also assumed to be a cause.

The ESO Optical Detector Team takes great care to eliminate suspicious materials in order to avoid this problem. Furthermore, the remaining components are high-grade cleaned and baked at high temperatures in a vacuum oven. For general interest, we analyzed possible outgassing of these devices.

In chapter "Experimental setup" the experimental setup used for this work is explained. A description of the cabling for the residual gas analyzer as well as a manual for its operation is given in the   Annex. The annex contains a table with key fragment ions for the identification of the evaporated substances. We characterize the probes used in chapter "Characterized probes" and summarize our work in chapter "Conclusions".