1. European X-Ray Free-Electron Laser Facility, Holzkoppel 4, 22869Schenefeld, Germany
2. Department Physik, Universität Siegen, Walter-Flex-Straße 3, 57072Siegen, Germany
3. Department of Mathematical, Physical and Computer Sciences, University of Parma, Parco Area Scienze 7/A, 43124Parma, Italy
4. Deutsches Elektronen-Synchrotron, Notkestraße 85, 22607Hamburg, Germany
5. European Synchrotron Radiation Facility, 71, Avenue des Martyrs, 38043Grenoble, France