Complete characterization of SU5: a VUV high resolution beamline with variable polarizations

The SU5 VUV beamline aims towards a dual scientific program: high resolutio n spectroscopy on dilute targets and linear/circular dichroism on anisotrop ic systems. A crossed planar/helicoidal electromagnetic undulator has been designed and built, providing both flux and variable polarizations. We have shown a complete versatility of the polarization state of the emitted ligh t with high polarization rates. Besides, the harmonics of the undulator can be suppressed owing to a gas filter, acting as a low-energy pass filter, w ith rejection factors above 10(5). The beamline is centered around a 6.65m off-plane Eagle normal incidence monochromator which has shown unprecedente d raw resolving powers. (117 000 at 21.6 eV, 133000 at 15.8 eV) with typica l flux in a 1/50000 bandwidth of 10(10)-10(9)photons/s between 6 and 30 eV. (C) 2001 Elsevier Science B.V. All rights reserved.