Figure 4: top : This photo illustrates the source change procedure in the clean room of ESTEC at Noordwijk. We see also on the photo the top part of the INTEGRAL payload. bottom : The calibration device built by the CEA/DAPNIA to accommodate, with an high mechanical precision, the calibration sources. We see from left to right the carrousel for the fluorescence target, the X-ray generator (in blue), and the source holder and collimator. (Photos S. Schanne).