X-ray optics. II - A technique for high resolution spectroscopy

A novel combination of optical elements and properties is combined to achieve high-spectral resolution using grazing incidence optics of modest quality. Analysis and ray tracing of examples show that using radial groove gratings at high blaze angles in the manner of an echelle spectrograph can provide high spectral resolution. This arrangement is compared to the conventional in-plane designs to show that the off-plane is superior in nearly every respect. Cross dispersion can be provided by the energy resolution of a CCD detector. Additional resolution can be squeezed from the system by strategic placement of gratings to take advantage of the azimuthal response of a Wolter X-ray optic.