Calculation of the Useful Width of a System of Two Concave Gratings Mounted at Grazing Incidence

摘要

This article investigates the possibility of increasing the resolving power of ultrasoft x-ray spectrographs by using a system of two concave gratings working at grazing angle. The distribution of brightness in the images given by this system from a point source is calculated. The useful width of the system is deduced and a comparison is made with the case of a single grating. (ERA citation 09:031635)