A fast X-ray timing capability on XEUS

The Rossi X-ray Timing Explorer has demonstrated that fast X-ray timing can be used to probe strong gravity fields around collapsed objects and constrain the equation of state of dense matter in neutron stars. These studies require extremely good photon statistics. In view of the huge collecting area of its mirrors, XEUS could make a unique contribution to this field. For this reason, it has been proposed to include a fast X-ray timing capability in the focal plane of the XEUS mirrors. We outline the scientific motivation for such a capability, present some sensitivity estimates, and discuss briefly a possible detector implementation.