Heidelberg 2015 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 62: Poster: Quantum Optics and Photonics III
Q 62.77: Poster
Thursday, March 26, 2015, 17:00–19:00, C/Foyer
A split-and-delay unit for the European XFEL: Enabling hard x-ray pump/probe experiments at the HED instrument — •Tobias Hovestädt1, Sebastian Roling1, Karen Appel2, Stefan Braun3, Peter Gawlitza3, Liubov Samoylova2, Harald Sinn2, Björn Siemer1, Frank Siewert4, Frank Wahlert1, Michael Wöstmann1, and Helmut Zacharias1 — 1Westfälische Wilhelms-Universität Münster — 2European XFEL GmbH, Hamburg — 3Fraunhofer IWS, Dresden — 4Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin
For the High Energy Density (HED) instrument at the SASE2 - Undulator at European XFEL an x-ray split-and-delay unit (SDU) is built covering photon energies from hν = 5 keV up to hν = 20 keV. This SDU will enable time-resolved x-ray pump / x-ray probe experiments as well as sequential diffractive imaging on a femtosecond to picosecond time scale. Further, direct measurements of the temporal coherence properties will be possible by making use of a linear autocorrelation. The set-up is based on geometric wavefront beam splitting, which has successfully been implemented at an autocorrelator at FLASH. The x-ray FEL pulses will be split by a sharp edge of a silicon mirror coated with Mo/B4C and W/B4C multilayers. Both partial beams will then pass variable delay lines. For different wavelengths the angle of incidence onto the multilayer mirrors will be adjusted in order to match the Bragg condition. For a photon energy of hν = 20 keV a grazing angle of θ = 0.57∘ has to be set, while for hν = keV the angle amounts to 2.3∘.