Performance of a broad-range X-ray spectrometer composed of a two-dime
nsional position-sensitive proportional counter (PSPC) and a flat crys
tal has been investigated. The 6cm x 6cm PSPC with 130 mu M position r
esolution along anode wires and 2mm wire spacing has been used. The ir
on K alpha(1) and K alpha(2) lines are clearly resolved with a ''mosai
c'' LiF(200) crystal at a certain crystal-PSPC distance. This is inter
preted as an intrinsic focusing effect due to the mosaic structure of
the flat crystal.