Abstract: A beamline combining the highest possible photon density on the sample with medium energy resolving power is under construction at the third generation storage ring ELETTRA in Trieste. It is designed to meet the requirements for the best instrumental performance of two imaging microscopes, which are going to be used for surface science research and micro- characterization of magnetic materials. The high photon density on the sample will be preserved within a rather wide photon energy range, between 20 to 1000 eV. In order to meet these requirements, building a simple while economical beamline we use a Variable Line Space (VLS) grating solution for the monochromator and adaptive plane elliptical mirrors for the re-focusing. In particular two low groove density VLS plane gratings (made by Jobin-Yvon) will cover the energy range between 20 and 1000 eV and a spherical grating will cover the lower energy (less than 20 eV) and focus the zero order light, still in grazing incidence mode. Before the monochromator, an internally cooled toroidal mirror (developed at ELETTRA) will pre-focus the radiation in different positions for the sagittal and tangential directions. After the exit slit, two different branches will host two couples of adaptive plane elliptical mirrors (developed in collaboration with S.E.S.O.) mounted in a Kirkpatrick-Baez configuration. The minimum final spot size will be of the order of 4 micrometer$+2$/ with a maximum photon density of the order of 10$+14$/ ph/sec/micrometer$+2$/. The advantage of the selected solutions and the overall expected performance will be described in detail. !9
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