1. Consiglio Nazionale delle Ricerche–Istituto Officina dei Materiali, Laboratorio TASC, 34149 Trieste, Italy
2. Department of Physics, Lund University, P.O. Box 118, 22100 Lund, Sweden
3. Department of Physics, University of Oulu, P.O. Box 3000, 90014 Oulu, Finland
4. MAX IV Laboratory, Lund University, P.O. Box 118, 22100 Lund, Sweden
5. Colegio Los Naranjos, Fuenlabrada, 28941 Madrid, Spain
6. Elettra-Sincrotrone Trieste, Area Science Park Basovizza, 34149 Trieste, Italy