Design of a high-flux low-energy synchrotron radiation monochromator

The characteristics and the performance of a new design low-energy high-flux synchrotron radiation beamline are here presented. This instrument, initially conceived for being applied to DAΦNE at the Frascati electron-positron collider, has been developed for a possible application to a fully dedicated synchrotron radiation third generation bending magnet. The beamline has a very innovative point in locating the first optics within the accelerator tunnel to collect as much flux as possible; the light is then focused on the entrance slit of a double normal and grazing incidence monochromator, to cover the 5-200 eV energy range; finally, a refocusing system collects the light from the monochromator exit slit and focuses it on the sample under study. The goal of this beamline is to deliver an high flux of photons in the energy range 5-200 eV with a resolution R larger than 10 000 for energy range 5-20 eV, and larger than 3000 for the range 30-200 eV. With this performance, the flux delivered is comparable to the one obtained by existing undulator beamlines: this shows that placing the first optical element as close as possible to the ring guarantees the required performance without the need of a straight section and an undulator.