VARIABLE GROOVE SPACED GRATING MONOCHROMATORS FOR SYNCHROTRON LIGHT-SOURCES

Several generic spectrometer types have been developed for research us ing VUV light at synchrotron radiation sources. They all have used gra tings with a constant groove spacing and they all have tried to incorp orate high resolution, high throughput, rejection of second and higher order radiation, and design simplicity in their construction. The use of gratings ruled with variable spaced grooves to reduce defocus, com a, and spherical aberration was suggested almost twenty years ago. An instrument using this grating concept was built five years ago for con ventional sources. The first monochromator using a variable line space d grating was installed at the National Synchrotron Light Source almos t two years ago, and a high resolution version of such an instrument h as been built at the Synchrotron Radiation Center operated by the Univ ersity of Wisconsin. In this presentation we review the development of monochromators using variable line space gratings and the possible ap plications of this type of instrumentation.