An x-ray spectrometer using a two-dimensional PSPC and a flat crystal

Performance of a broad-range x-ray spectrometer composed of a twodimensional position-sensitive proportional counter (PSPC) and a flat crystal has been investigated. The 6 cm × 6 cm PSPC with 130 μm position resolution along anode wires and 2 mm wire spacing has been used. The iron Kα1 and Kα2 lines are clearly resolved with a "mosaic" LiF(200) crystal at a certain crystal-PSPC distance. This is interpreted as an intrinsic focussing effect due to the mosaic structure of the flat crystal.