1. Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
2. Department of Applied Physics, Stanford University, Stanford, CA 94305, USA.
3. Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin, Germany.
4. Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.
5. National Science Foundation BioXFEL Science and Technology Center, Buffalo, NY 14203, USA.
6. Division of Physics and Astronomy, Kyoto University, Kyoto 606-8501, Japan.
7. Pulse Institute, Stanford University and SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
8. Argonne National Laboratory, Lemont, IL 60439, USA.
9. Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208, USA.