Dr
Wojciech Roseker
(Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany)
One of the important challenges in condensed matter science is to understand ultrafast, atomic-scale fluctuations that dictate dynamic processes in equilibrium and non-equilibrium materials. These fluctuations can be measured on the relevant time scale by time-correlating coherent scattering speckle patterns taken with ultrashort X-ray pulses from a free electron laser (FEL) in an X-ray Photon Correlation Spectroscopy (XPCS) experiment if the time separation of the X-ray pulses can be controlled on that very timescale. Here, we report an important step towards reaching that goal by using a prototype perfect crystal-based split-and-delay system, capable of splitting individual X-ray pulses and introducing femto- to nanosecond time delays. We show the results of the first ultrafast XPCS experiment[1] at LCLS where split X-ray pulses were used to measure the dynamics of gold nanoparticles suspended in a liquid and verify the validity of the Stokes-Einstein relation on ns-ps timescales. We show how reliable speckle contrast values can be extracted even from very low intensity FEL speckle patterns by applying maximum likelihood fitting, thus demonstrating the potential of a split-and-delay approach for dynamics measurements at FEL sources. This capability promises to elucidate the underlying dynamics of a wide variety of systems and will enable the discovery of new physical processes therein.
References:
[1] Roseker, W. et al. Nature Communications 9,1704 (2018).
Dr
Wojciech Roseker
(Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany)
Dr
Stephan Hruszkewycz
(Argonne National Laboratory, Argonne, Illinois 60439 USA)
Dr
Felix Lehmkühler
(Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany)
Dr
Michael Walther
(Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany)
Dr
Horst Schulte-Schrepping
(Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany)
Dr
Sooheyong Lee
(Korea Research Institute of Standards and Science, Daejeon 305-340, Rep.of Korea)
Dr
Taito Osaka
(RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan)
Dr
Lothar Strüder
(PNSensor GmbH, Otto-Hahn-Ring 6, 81739 München, Germany )
Dr
Robert Hartmann
(PNSensor GmbH, Otto-Hahn-Ring 6, 81739 München, Germany )
Dr
Marcin Sikorski
(European X-Ray Free-Electron Laser Facility, Holzkoppel 4, 22869 Schenefeld, Germany)
Dr
Sanghoon Song
(LAC National Accelerator Laboratory, Menlo Park, CA 94025, USA)
Aymeric Robert
(LAC National Accelerator Laboratory, Menlo Park, CA 94025, USA)
Dr
Paul Fuoss
(LAC National Accelerator Laboratory, Menlo Park, CA 94025, USA)
Prof.
Mark Sutton
(McGill University, Montreal, Quebec H3A2T8, Canada)
Dr
Brian Stephenson
(Argonne National Laboratory, Argonne, Illinois 60439 USA)
Prof.
Gerhard Grübel
(Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany)
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