23 May 2017 Characterization of the LCLS “nanosecond two-bunch” mode for x-ray speckle visibility spectroscopy experiments
Author Affiliations +
The generation of two X-ray pulses with tunable nanosecond scale time separations has recently been demonstrated at the Linac Coherent Light Source using an accelerator based technique. This approach offers the opportunity to extend X-ray Photon Correlation Spectroscopy techniques to the yet unexplored regime of nanosecond timescales by means of X-ray Speckle Visibility Spectroscopy. As the two pulses originate from two independent Spontaneous Amplified Stimulated Emission processes, the beam properties fluctuate from pulse pair to pulse pair, but as well between the individual pulses within a pair. However, two-pulse XSVS experiments require the intensity of the individual pulses to be either identical in the ideal case, or with a accurately known intensity ratio. We present the design and performances of a non-destructive intensity diagnostic based on measurement of scattering from a transparent target using a high-speed photo-detector. Individual pulses within a pulse pair with time delays as short as 0.7 ns can be resolved. Moreover, using small angle coherent scattering, we characterize the averaged spatial overlap of the focused pulse pairs. The multi-shot average-speckle contrasts from individual pulses and pulse pairs are compared.
Conference Presentation
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Yanwen Sun, Yanwen Sun, Diling Zhu, Diling Zhu, Sanghoon Song, Sanghoon Song, Franz-Josef Decker, Franz-Josef Decker, Mark Sutton, Mark Sutton, Karl Ludwig, Karl Ludwig, Wojciech Roseker, Wojciech Roseker, Gerhard Grübel, Gerhard Grübel, Stephan Hruszkewycz, Stephan Hruszkewycz, G. Brian Stephenson, G. Brian Stephenson, Paul H. Fuoss, Paul H. Fuoss, Aymeric Robert, Aymeric Robert, } "Characterization of the LCLS “nanosecond two-bunch” mode for x-ray speckle visibility spectroscopy experiments", Proc. SPIE 10237, Advances in X-ray Free-Electron Lasers Instrumentation IV, 102370N (23 May 2017); doi: 10.1117/12.2265454; https://doi.org/10.1117/12.2265454

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