Design of a low-energy extended UV beamline for bending magnet radiation

The design of a beamline, covering the energy range from 5 to 200 eV, based on a double incidence spherical gratings monochromator designed for ELETTRA bending magnet radiation is described. The monochromator consists of two interchangeable sets of gratings working one at normal incidence and the other at grazing incidence, to cover the entire spectral interval. The photon energy range of interest is covered with five gratings (two at normal and three at grazing incidence) achieving a resolving power of the order of 10000 and a photon flux approximately 1012 (photons/s/0.1% bandwidth/mm2) at the sample position.