A monochromator based on wic multilayers of 40Å layer spacing

ABSTRACT A simple two-mirror monochromator based on multilayer films has been developed for use with synchrotron radiation. Measurements of the performance of this monochromator and the characterization of a typical component mirror are described.1. INTRODUCTIONMultilayer x-ray mirrors are one-dimensional periodic structures fabricated of alternating layers of materials of high and low values of the refractive index. The layer periodicity simulates the lattice of a natural crystal, but with a longer lattice constant, and can therefore be used for diffraction of soft x-ray si.High reflectivity, adjustable layer spacing, stability under high-intensity radiation, and ultrahigh vacuum compatibility suggest that multilayers may be useful as monochromators. In terms of currently usable monochromatic wavelengths, multilayers fill the gap, albeit generally with poorer resolution, between gratings, usable at long wavelengths, and natural crystals, which are limited to producing monochromatic radiation with wavelengths shorter than 25A2. Many applications in reflectometry and optics, x-ray lithography, biology, and medicine require high fluxes without extremely high resolution. Unlike gratings and Langmuir-Blodgett films, multilayers can handle large radiation fluxes.2. DESIGN OF THE TWO-MIRROR MONOCHROMATORThe monochromator we have constructed is of a two-mirror, fixed-output-angle design. Variation of the wavelength is accomplished by rotation about an axis fixed at the surface of the first multilayer. The present configuration utilizes multilayers deposited on 3" silicon wafers mounted on 3/16" thick OFHC copper backing plates that fit into a* To whom correspondences should be addressed.