Recent developments in the field of far U.V. monochromators using toroidal holographic gratings

Abstract

After a short review of the method of calculation and optimisation of grazing incidence toroidal holographic gratings, we present a summary of the characteristic of a wide range of such gratings working in the 15–1000 Å range with instrumental resolutions between 0.007 and 0.6 Å. The main characteristics of such systems, the parameters limiting their resolution and their performance in the direct and reverse use configurations are discussed. We illustrate in a particular case the aberration correction possibilities and performances of Type I and Type IV toroidal gratings for monochromator configurations.