A large area gas proportional scintillation counter for balloon borne solar X-ray spectrometry

A compact xenon filled gas proportional scintillation counter (GPSC) having a window area of 12.5 cm/sup 2/ coupled to low weight, low volume and low power associated electronics is described to be used in a balloon gondola to fly at high altitudes (30 to 40 km) and measure X-ray spectra in the 20 to 80 keV energy range, arising from solar flares. The detector has an energy resolution of 4.3% at 59.6 keV for the full window opening, and 2.7% for a 2-mm-diameter collimated X-ray beam.