Optimization of the Rowland circle grating for high-resolution astrophysical spectrometers working at soft x-ray and EUV wavelengths

The continued maturation of X-ray and EUV astronomy has created a requirement for high-resolution spectroscopy to resolve spectral features and measure line profiles and Doppler shifts. This paper considers the familiar fixed-grating spectrometer (Rowland configuration) operating at grazing incidence behind the focus of a grazing-incidence telescope. By optimizing the grating shape and grating-detector geometry, it is found that a peak resolving power near 10 to the 4th and greater should be achievable in the 50-500-A band. An important innovation to the standard configuration is the addition of an elliptical mirror. The optimization technique used is adaptable to other geometries as well as other applications in which a fixed grating is desired.