Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 43: Poster Session II - MA 141/144 (Surface Spectroscopy on Kondo Systems; Frontiers of Surface Sensitive Electron Microscopy; Methods: Scanning Probe Techniques+Electronic Structure Theory+Other; Time-Resolved Spectroscopy of Surface Dynamics with EUV and XUV Radiation; joined by SYNF posters)
O 43.42: Poster
Dienstag, 26. Februar 2008, 18:30–19:30, Poster F
first test of a beam splitter and delay line for the XUV at FLASH — •Rolf Mitzner1, Björn Siemer1, Marco Rutkowski1, Sebastian Roling1, Matthias Neeb2, Tino Noll2, Kai Tiedtke3, Wolfgang Eberhardt2, and Helmut Zacharias1 — 1Physikalisches Institut, Westfälische Wilhels-Universität, 48149 Münster — 2BESSY GmbH, Albert Einstein Str. 15, 12489 Berlin — 3HASYLAB, DESY, 22603 Hamburg
In order to do jitter-free X-ray pump and probe experiments at the Free Electron Laser in Hamburg (FLASH) as well as to characterize the temporal structure of its high power pulses a novel beam splitter and delay unit (autocorrelator) has been designed and constructed [1]. Based on geometrical beam splitting by a mirror edge the apparatus covers the XUV energy range up to photon energies of 200 eV providing a total delay of about 20 picoseconds with femtosecond resolution. Using 13.5 nm radiation from the FEL the beam has been split in two beams delayed to each other. The shape of the split beams as well as its fluctuations has been recorded for different delays up to several picoseconds. Overlapping the split beams under a small angle 10 m behind the autocorrelator lateral interference fringes have been observerved at zero delay between the two beams. When changing the path difference the fringes have been disappeared thus demonstrating the proper function of the delay line in the XUV. The visibility of the fringes as a function of the delay (path length difference) should allow the direct determination of the average coherence time of the FEL pulses. [1] R. Mitzner et.al., Proc. Of SPIE 592000D (2005)