Compressed gaseous xenon gamma-ray detector with high energy resolution

A high pressure xenon parallel plate ionization chamber was designed for measurements of cosmic gamma-ray lines. The 3 liter chamber was filled with 0.6 g/cu cm density of xenon, mixed with hydrogen for increasing the drift velocity of the electrons. The noise-subtracted energy resolution was 1.3 percent FWHM at energy 1 MeV. This chamber was installed on the space station 'MIR', currently in orbit and the measurements are being carried out. No energy resolution degradation has been observed for two years, despite the strong irradiation by the Brazil anomaly.