1. II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, 50937 Köln, Germany
2. Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
3. Division of Synchrotron Radiation Research, Lund University, Box 118, 22100 Lund, Sweden
4. Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Wien, Austria
5. Division of Synchrotron Radiation Research and the MAX IV Laboratory, Lund University, Box 118, 22100 Lund, Sweden
6. Department of Applied Physics, Aalto University, P.O. Box 11100, FI-00076 Aalto, Finland