A high-throughput high-spectral-resolution grating X-ray spectrometer for XEUS

XEUS1,3 is a single focus X-ray telescope which will provide a collecting area of 10-20 m(2) at 1 keV with angular resolution 2-5 arc seconds. Such a large area can be achieved with low mass using pore optics manufactured from silicon.(2) A high resolution X-ray spectrometer which can exploit this enormous collecting area to the full is difficult to construct. Non-dispersive devices are limited by solid state device technology and objective grating spectrometers require a very large number of massive high quality gratings. We describe an alternative focal plane grating spectrometer which employs relatively few plane reflection gratings and focusing MCP square pore optics to utilize a large fraction of the full aperture from the primary mirror.