Coverage of the XMM-CDFS survey (solid black lines) in the 2 − 10 keV (left panel) and 5 − 10 keV band (right panel), defined as the fraction of simulated sources which were successfully detected as a function of their output flux, and normalized to the area probed by the catalogues. The dotted red lines show, for comparison, the same quantity for Chandra (left panel: 4 Ms survey, X11; right panel: 1 Ms survey, Rosati et al. 2002). The dashed blue line in the right panel shows the coverage for the XMM-Newton Lockman Hole (Brunner et al. 2008). We have not shown in the right panel the CDFS 4 Ms (Lehmer et al. 2012) since formally it is in a softer band (4 − 8 keV).