Recent Progress in the Development of a Gas Scintillation Proportional Counter for X-Ray Astronomy

In X-ray astronomy there is a need for a large-area satellite-borne detector, which has a significantly better energy resolution than the classical proportional counter, in order to observe det-ailed X-ray spectral features in a variety of astrophysical objects. A gas scintillation proportional counter, (GSPC), seems to fulfill these requirements. Results are presented demonstrating: (a) an energy resolution of 8.35% (FWHM) at 6 keV, (b) the ability of the GSPC to reject more than 90% of the background events normally falling within a selected energy window. In addition results are presented on the optimisation of the working parameters of the GSPC, and on the development of a large area detector.