Table 2: Predicted number of faint, high- X-ray sources.

Mission conceptPSF HPDMosaicsTotal FOVz = 4-5z = 5–5.8
Arcsecdeg2 ( )

Athena* 10  Msec 10
Athena* 5  Msec 1.0
Athena 5  Msec 7.0

WFXT* 10  Msec 24
WFXT* 5  Msec 4
WFXT 5  Msec 60

Super-Chandra 2  Msec 0.6
Super-Chandra 2  Msec 2.4
Super-Chandra 1  Msec 0.2
Super-Chandra 1  Msec 0.6

*Close to confusion limit (40 beams per source).