1. Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany
2. ESRF-The European Synchrotron, CS 40220, 38043 Grenoble Cedex 9, France
3. Photon Science, DESY, D-22607 Hamburg, Germany
4. Laboratory of Crystallography, Material Physics and Technology at Extreme Conditions, Universität Bayreuth, D-95440 Bayreuth, Germany