Gem detectors for X-ray astronomy

Applicability of a Gas Electron Multiplier (GEM) detector for the X-ray astronomy will be studied. The final goal of this feasibility study is to produce a sealed GEM detector designed for space flights and several GEM detectors will be constructed during the project. The design of the first prototype GEM with a double GEM foil structure, and its data acquisition system is described. The front-end electronics is installed within the gas volume. To qualify as a space instrument, the detector system has to sustain reliable long-term operation. Therefore special attention is paid to the measurements of the outgassing properties of the construction materials and on the aging characteristics of the detector. The design criteria of the detector include the following specifications: 1) position resolution better than 0.2 mm at 6 keV, 2) energy resolution 20% at 6 keV and 3) large active area (about 15 cm×15 cm) with a thin Be window (75–150 μm).