Spectroscopy in X-Ray Astronomy Using Gas Scintillation Cameras

Experimental results obtained from a new, position sensitive, gas scintillation proportional counter are presented. The counter, for use in X-ray astronomy as a focal plane instrument in conjunction with a grazing incidence imaging telescope, features a useful aperture of ~ 7 cm, a two-stage scintillation region and a seven photomultiplier tube Anger camera read-out system. An energy resolution of ¿ 20% FWHM at 1.25 keV (< 10% at 6 keV) and a position resolution of 900 ¿m at 6 keV at the centre of the useful aperture are achieved.