1. Max Planck Institute for the Structure and Dynamics of Matter 1 , Luruper Chaussee 149, 22761 Hamburg, Germany
2. Center for Free-Electron Laser Science 2 , Luruper Chaussee 149, 22761 Hamburg, Germany
3. University of Southampton 3 , Southampton SO17 1BJ, United Kingdom
4. Department of Physics, University of Hamburg 4 , Jungiusstrasse 9, 20355 Hamburg, Germany
5. Department of Earth Science and Engineering, Imperial College London 5 , London SW7 2AZ, United Kingdom