A large area gas proportional scintillation counter for solar X-ray spectrometry in a balloon born experiment

A compact xenon filled Gas Proportional Scintillation Counter 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 5.0% at 59.6 keV for the full window opening.