@article{SchickLeGuyaderPontiusetal.2016, author = {Schick, Daniel and Le Guyader, Loic and Pontius, Niko and Radu, Ilie and Kachel, Torsten and Mitzner, Rolf and Zeschke, Thomas and Schuessler-Langeheine, Christian and F{\"o}hlisch, Alexander and Holldack, Karsten}, title = {Analysis of the halo background in femtosecond slicing experiments}, series = {Journal of synchrotron radiation}, volume = {23}, journal = {Journal of synchrotron radiation}, publisher = {International Union of Crystallography}, address = {Chester}, issn = {1600-5775}, doi = {10.1107/S160057751600401X}, pages = {700 -- 711}, year = {2016}, abstract = {The slicing facility FemtoSpeX at BESSY II offers unique opportunities to study photo-induced dynamics on femtosecond time scales by means of X-ray magnetic circular dichroism, resonant and non-resonant X-ray diffraction, and X-ray absorption spectroscopy experiments in the soft X-ray regime. Besides femtosecond X-ray pulses, slicing sources inherently also produce a so-called `halo' background with a different time structure, polarization and pointing. Here a detailed experimental characterization of the halo radiation is presented, and a method is demonstrated for its correct and unambiguous removal from femtosecond time-resolved data using a special laser triggering scheme as well as analytical models. Examples are given for time-resolved measurements with corresponding halo correction, and errors of the relevant physical quantities caused by either neglecting or by applying a simplified model to describe this background are estimated.}, language = {en} } @article{SchickEckertPontiusetal.2016, author = {Schick, Daniel and Eckert, Sebastian and Pontius, Niko and Mitzner, Rolf and F{\"o}hlisch, Alexander and Holldack, Karsten and Sorgenfrei, Florian}, title = {Versatile soft X-ray-optical cross-correlator for ultrafast applications}, series = {Structural dynamics}, volume = {3}, journal = {Structural dynamics}, publisher = {American Institute of Physics}, address = {Melville}, issn = {2329-7778}, doi = {10.1063/1.4964296}, pages = {054304-1 -- 054304-8}, year = {2016}, abstract = {We present an X-ray-optical cross-correlator for the soft (> 150 eV) up to the hard X-ray regime based on a molybdenum-silicon superlattice. The cross-correlation is done by probing intensity and position changes of superlattice Bragg peaks caused by photoexcitation of coherent phonons. This approach is applicable for a wide range of X-ray photon energies as well as for a broad range of excitation wavelengths and requires no external fields or changes of temperature. Moreover, the cross-correlator can be employed on a 10 ps or 100 fs time scale featuring up to 50\% total X-ray reflectivity and transient signal changes of more than 20\%. (C) 2016 Author(s).}, language = {en} } @misc{SchickEckertPontiusetal.2016, author = {Schick, Daniel and Eckert, Sebastian and Pontius, Niko and Mitzner, Rolf and F{\"o}hlisch, Alexander and Holldack, Karsten and Sorgenfrei, Florian}, title = {Versatile soft X-ray-optical cross-correlator for ultrafast applications}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1331}, issn = {1866-8372}, doi = {10.25932/publishup-43696}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-436962}, pages = {054304-1 -- 054304-8}, year = {2016}, abstract = {We present an X-ray-optical cross-correlator for the soft (> 150 eV) up to the hard X-ray regime based on a molybdenum-silicon superlattice. The cross-correlation is done by probing intensity and position changes of superlattice Bragg peaks caused by photoexcitation of coherent phonons. This approach is applicable for a wide range of X-ray photon energies as well as for a broad range of excitation wavelengths and requires no external fields or changes of temperature. Moreover, the cross-correlator can be employed on a 10 ps or 100 fs time scale featuring up to 50\% total X-ray reflectivity and transient signal changes of more than 20\%. (C) 2016 Author(s).}, language = {en} }