1. II. Physikalisches Institut, Universität zu Köln, Cologne, D-50937, Germany
2. Institute of Physics, Bijenička cesta 46, 10000, Zagreb, Croatia
3. Faculty of Physics, Vienna University, Boltzmanngasse 5, 1090, Vienna, Austria
4. MAX IV Laboratory and Division of Synchrotron Radiation Research, Lund University, Box 118, 22100 Lund, Sweden
5. Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14 Km 163.5, I-34149 Trieste, Italy