1. Kirensky Institute of Physics, Federal Research Center KSC SB RAS, 660036 Krasnoyarsk, Russia
2. Institut für Mineralogie, University of Münster, Corrensstr. 24, 48149 Münster, Germany
3. Division of Synchrotron Radiation Research, Department of Physics, Lund University, Box 118, Lund 221 00, Sweden
4. Materials Science and Applied Mathematics, Malmö University, Malmö 204 06, Sweden