A primary scintillation gated high pressure position sensitive ,gas scintillation proportionalcounter (HPGSPC) for applications to x -ray astronomyS. Giarrusso, G. Manzo, S. ReIsituto di Fisica Cosmica ed Applicazioni dell' Informatica del CNR, via M. Stabile 172,90139 - Palermo, ItalyABSTRACTWe describe a new instrument for x -ray astronomy.The instrument, based on a high pressure (5 atm.), xenon filled, position sensitive Gas ScintillationProportional counter (HPGSPC) is expected to feature an energy resolution better than 4% at 60 keV, anangular resolution of approximately 20 arc -minutes over the full energy range (4 to 100 keV) and a field ofview (FOV) of up 30x30 degrees.A prototype flight unit of the gas cell on which the instrument is based is presently under technologicaldevelopment in the framework of the SAX project.INTRODUCTIONGas Scintillation Proportional Counters have found useful application in the field of x -ray astronomy up