Inflight performance of the position sensitive proportional counter on board the X-ray astronomy satellite ROSAT

Abstract

Two redundant position sensitive proportional counters (PSPC) operating in the energy range from 0.1 to 2.4 keV are the prime focal plane instruments on board the X-ray astronomy satellite Rosat, Rosat was launched on June 1, 1990 and has operated highly efficiently since then. The authors report on the in-orbit performance of the PSPC. Apart from its food energy and position resolution ( delta E/E=41% and 230 mu m full width at half maximum at 1 keV, respectively) the detector has a very high charged particle background rejection efficiency of 99.8%. The gas gain of the detector is very stable. Short-time variations due to thermal variations over one orbit are less than 1%. The long-term drift over one month is 0.5%. >