[1] Aarhus Univ, Dept Phys & Astron, Interdisciplinary Nanosci Ctr iNANO, DK-8000 Aarhus C, Denmark
[2] Deutsch Elektronen Synchrotron DESY, Hamburg, Germany
[3] Tech Univ Denmark, Dept Phys, Ctr Atom Scale Mat Design, DK-2800 Lyngby, Denmark
[4] Martin Luther Univ Halle Wittenberg, Dept Phys, D-06099 Halle, Germany
[5] Max Planck Inst Microstruct Phys, D-06120 Halle, Germany
[6] STFC Rutherford Appleton Lab, Cent Laser Facil, Didcot OX11 0QX, Oxon, England
[7] Univ Trieste, Dept Phys, Via Valerio 2, I-34127 Trieste, Italy
[8] Elettra Sincrotrone Trieste SCpA, AREA Sci Pk,SS 14 Km 163-5, I-34149 Trieste, Italy
[9] CNR, Inst Complex Syst, Via Fosso del Cavaliere 100, I-00133 Rome, Italy
[10] CNR, IOM, Lab TASC, AREA Sci Pk,SS 14 Km 163-5, I-34149 Trieste, Italy