1. Department of Physics, Stockholm University, 10691 Stockholm, Sweden
2. Photon Science, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
3. DESY NanoLab, Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg, Germany
4. PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, 94305 California, United States
5. Physics Department, University of Hamburg, 20148 Hamburg, Germany