1. Photon Science Division Paul Scherrer Institut Villigen CH‐5232 Switzerland
2. Departamento de Física Universidade Federal de Minas Gerais C.P. 702 Belo Horizonte Minas Gerais 30123 Brazil
3. Elettra‐Sincrotrone Trieste S.C.p.A, S.S 14‐km 163.5 in AREA Science Park, Basovizza Trieste 34149 Italy
4. Department of Energy Conversion and Storage Technical University of Denmark Kgs. Lyngby 2800 Denmark
5. Institut de Physique École Polytechnique Fédérale de Lausanne Lausanne CH‐1015 Switzerland