First results from the high resolution XUV undulator beamline BW3 at HASYLAB

In English Initial results from the XUV undulator beamline at the 4.5 GeV storage ring DORIS are reported. The beamline consists of three different undulators mounted on a revolver type device and a modified SX-700 plane grating monochromator with a spherical focusing mirror. It covers the spectral range from 50–2000 eV with excellent spectral resolution and high photon flux. In the energy range 400 eV to 1 keV a spectral resolution estimated to 4500–9000 is obtained which is slightly better than the best values previously reported. In the energy range 50–1700 eV the photon flux is of the order of 1011–1013/s for a resolving power of a thousand normalized to a ring current of 100 mA. A study of the photofragmentation of H2O following K-shell excitation energetically close to the oxygen K-edge at 540 eV demonstrates the excellent performance of the beamline, in particular for the investigation of secondary processes where a high flux is necessary.