A Bragg spectrometer for stellar X-ray astronomy.

Poor energy resolution and the steeply varying continuum spectrum make it impossible to obtain with proportional counters an unambiguous identification of certain emission features of Sco X-1. For this reason a Bragg crystal spectrometer was constructed. The instrument, flown successfully aboard an Aerobee-170 rocket, scanned the spectral range from 2.4 to 2.9 keV. The spectrometer consists of two large reflecting crystals of synthetic graphite. The results obtained during the flight of the instrument clearly indicate that the Bragg method can yield much higher sensitivity to line emission than can proportional counter methods.