X-ray monochromator designs based on extreme off-plane grating mountings

Several monochromator designs are presented in which the beam is incident on the grating nearly parallel to the grooves. The efficiency of such mountings, when obeying the blaze condition, is much higher than that of classical arrangements. Because only the Snell's components of the angular coordinates are varied, this high efficiency is found over the complete wavelength range. With the designs described the wavelength region from 0.6 to 100 nm can be covered without interchanging gratings. For each wavelength the spectral resolution can be increased to ~10(4). Entrance and exit slit positions and the corresponding beam orientations are fixed.