1. Deutsches Elektronen-Synchrotron (DESY), D-22607 Hamburg, Germany.
2. University of Hamburg, Physics Department, D-20355 Hamburg, Germany.
3. Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology, D-76344 Eggenstein-Leopoldshafen, Germany.
4. National Research Nuclear University MEPhI, Moscow 115409, Russia.