Bent crystal spectrometer for solar X-ray spectroscopy

Abstract

A bent crystal spectrometer employs a collimated beam of X-rays incident on the crystal over a range of Bragg angles determined by the orientation and curvature of the crystal surface. It provides continuous and simultaneous coverage of all X-ray wavelengths within its spectral range. In-flight testing for solar X-ray spectroscopy was performed using a small instrument to supplement the wavelength coverage of several scanning spectrometers used to study solar active regions in the 9-24 A range. Later testing included modifications to alleviate problems caused by ultraviolet radiation. Future usage of the device will include studies of time variable emission from solar flares or discrete galactic X-ray sources, and the first major experiment to utilize bent crystal spectrometers will be the Solar Maximum Mission satellite in 1979.