Performance of microstrip proportional counters for x-ray astronomy on spectrum-roentgen-gamma

DSRI will provide a set of four imaging proportional counters for the Danish-Soviet X-ray telescopes XSPECT/SODART. The sensor principle is based on the novel micro-strip proportional counter (MSPC), where the strip electrodes are deposited by photolithography onto a rigid substrate. The MSPC offers many advantages : A uniform gas gain, an excellent energy resolution, the possibility to match the strip pitch to the desired positron resolution, a fast charge collection and low operating voltages.

However, a stable behaviour of the MSPC requires a careful choice of both substrate and strip electrode material. The low energy detectors will be equipped with polyimide windows of 0.5 pm thickness, providing a high quantum efficiency even at 200 eV with an energy resolution comparable to that of solid state detectors.

The MSPC is capable of operating at high counting rates (iO ph s1) and the electronics is designed to match this capability.