European X Ray Free Electronic Laser Facility

Hamburg, Germany

European X Ray Free Electronic Laser Facility

Hamburg, Germany
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Boesenberg U.,European X Ray Free Electronic Laser Facility | Samoylova L.,European X Ray Free Electronic Laser Facility | Roth T.,European X Ray Free Electronic Laser Facility | Zhu D.,SLAC | And 9 more authors.
Optics Express | Year: 2017

A precise spectral characterization of every single pulse is required in many x-ray free-electron laser (XFEL) experiments due to the fluctuating spectral content of self-amplified spontaneous emission (SASE) beams. Bent single-crystal spectrometers can provide sufficient spectral resolution to resolve the SASE spikes while also covering the full SASE bandwidth. To better withstand the high heat load induced by the 4.5 MHz repetition rate of pulses at the forthcoming European XFEL facility, a spectrometer based on single-crystal diamond has been developed. We report a direct comparison of the diamond spectrometer with its Si counterpart in experiments performed at the Linac Coherent Light Source. © 2017 Optical Society of America.


Kurta R.P.,German Electron Synchrotron | Dronyak R.,German Electron Synchrotron | Altarelli M.,European X ray Free Electronic Laser Facility | Weckert E.,German Electron Synchrotron | And 2 more authors.
New Journal of Physics | Year: 2013

While the implementation of single-particle coherent diffraction imaging for non-crystalline particles is complicated by current limitations on photon flux, hit rate and sample delivery, the concept of many-particle coherent diffraction imaging offers an alternative way of overcoming these difficulties. In this paper, we present a direct, non-iterative approach for the recovery of the diffraction pattern corresponding to a single particle using coherent x-ray data collected from a two-dimensional disordered system of identical particles; this approach does not require a priori information about the particles and can be applied to the general case of particles without symmetry. The reconstructed single-particle diffraction pattern can be directly used in common iterative phase retrieval algorithms to recover the structure of the particle. © IOP Publishing and Deutsche Physikalische Gesellschaft.


Kurta R.P.,German Electron Synchrotron | Altarelli M.,European X Ray Free Electronic Laser Facility | Vartanyants I.A.,German Electron Synchrotron | Vartanyants I.A.,National Research Nuclear University MEPhI
Advances in Condensed Matter Physics | Year: 2013

Angular X-ray cross-correlation analysis (XCCA) is an approach to study the structure of disordered systems using the results of X-ray scattering experiments. In this paper we summarize recent theoretical developments related to the Fourier analysis of the cross-correlation functions. Results of our simulations demonstrate the application of XCCA to two- and three-dimensional (2D and 3D) disordered ensembles of particles. We show that the structure of a single particle can be recovered using X-ray data collected from a 2D disordered system of identical particles. We also demonstrate that valuable structural information about the local structure of 3D systems, inaccessible from a standard small-angle X-ray scattering experiment, can be resolved using XCCA. © 2013 R. P. Kurta et al.


Altarelli M.,European X ray Free Electronic Laser Facility
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2011

Activities on free-electron laser (FEL) X-ray sources, based on linear accelerators, to produce spatially coherent, ultra-short (∼100 fs) pulses with very high peak brilliance (1028-1032 photons/s/mm2/mrad2/0.1% BW) are summarized, with special emphasis on the European XFEL project in Hamburg. The scientific case includes time-resolved studies of dynamics on sub-ps scales, structural studies by imaging of non-periodic systems, and investigation of high energy-density phenomena such as non-linear X-ray optics and the production of warm dense matter. Examples are presented, with reference to the experience gained on the presently operational facilities, FLASH at DESY, Hamburg and LCLS in Stanford, California. © 2011 Elsevier B.V. All rights reserved.


Altarelli M.,European X ray Free Electronic Laser Facility | Altarelli M.,German Electron Synchrotron | Kurta R.P.,German Electron Synchrotron | Vartanyants I.A.,European X ray Free Electronic Laser Facility
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

In a recent paper x-ray scattering intensity correlations around a ring, in the speckle diffraction pattern of a colloidal glass, were shown to display a remarkable ∼cos (nφ) dependence on the angular coordinate φ around the ring, with integer index n depending on the magnitude of the scattering wave vector. With an analytical derivation that preserves full generality in the Fraunhofer diffraction limit, we clarify the relationship between this result and previous x-ray studies of bond-orientation order, and provide a sound basis to the statement that the angular intensity correlations deliver information on local bond arrangements in a disordered (or partially ordered) system. We present a detailed analysis of the angular cross-correlation function and show its applicability for studies of a wide range of structural properties of disordered systems, from local structure to spatial correlations between distant structural elements. © 2010 The American Physical Society.


Altarelli M.,European X ray Free Electronic Laser Facility
Crystallography Reports | Year: 2010

Activities on free-electron laser (FEL) x-ray sources, based on linear accelerators, to produce spatially coherent, ultra-short (∼100 fs) pulses with very high peak brilliance (10 28-10 32 photons/s/mm 2/mrad 2/0.1% BW) are summarized. The scientific case includes time-resolved studies of dynamics on sub-ps scales, structural studies by imaging of non-periodic systems, and investigation of high energy-density phenomena such as non-linear x-ray optics and the production of warm dense matter. Examples are presented, with emphasis on the operational facilities, FLASH at DESY, Hamburg and LCLS in Stanford, California, and on the European XFEL project in Hamburg. © 2010 Pleiades Publishing, Ltd.


Madsen A.,European X Ray Free Electronic Laser Facility | Als-Nielsen J.,Copenhagen University | Hallmann J.,European X Ray Free Electronic Laser Facility | Roth T.,European X Ray Free Electronic Laser Facility | Lu W.,European X Ray Free Electronic Laser Facility
Physical Review B - Condensed Matter and Materials Physics | Year: 2016

β-brass exhibits an archetypical example of an order-disorder transition with a critical behavior that was previously investigated by neutron scattering. The data were well described by the three-dimensional (3d) Ising model but the relatively crude experimental resolution prevented an in-depth examination of the single-length scaling hypothesis, a cornerstone in the theory of critical phenomena. With the development of synchrotron x-ray experiments, high-resolution data could be recorded and surprisingly it was found that the single-length scaling did not hold in most critical systems, possibly due to strain originating from surface defects and/or impurities. In this paper we demonstrate single-length critical behavior using high-resolution x-ray scattering in β-brass. The investigations confirm that β-brass behaves like a 3d Ising system over a wide range of length scales comprising correlated clusters of millions of atoms. To vary the surface sensitivity, experiments have been performed both in Bragg reflection and Laue transmission geometries but without any substantial differences observed in the scaling and critical behavior. © 2016 American Physical Society.


van Thor J.J.,Imperial College London | Madsen A.,European X Ray Free Electronic Laser Facility
Structural Dynamics | Year: 2015

In order to exploit the femtosecond pulse duration of X-ray Free-Electron Lasers (XFEL) operating in the hard X-ray regime for ultrafast time-resolved protein crystallography experiments, critical parameters that determine the crystallographic signal-to-noise (I/σI) must be addressed. For single-crystal studies under low absorbed dose conditions, it has been shown that the intrinsic pulse intensity stability as well as mode structure and jitter of this structure, significantly affect the crystallographic signal-to-noise. Here, geometrical parameters are theoretically explored for a three-beam scheme: X-ray probe, optical pump, X-ray probe (or "probe-pump-probe") which will allow experimental determination of the photoinduced structure factor amplitude differences, ΔF, in a ratiometric manner, thereby internally referencing the intensity noise of the XFEL source. In addition to a noncollinear split-beam geometry which separates un-pumped and pumped diffraction patterns on an area detector, applying an additional convergence angle to both beams by focusing leads to integration over mosaic blocks in the case of wellordered stationary protein crystals. Ray-tracing X-ray diffraction simulations are performed for an example using photoactive yellow protein crystals in order to explore the geometrical design parameters which would be needed. The specifications for an X-ray split and delay instrument that implements both an offset angle and focused beams are discussed, for implementation of a probe-pump-probe scheme at the European XFEL. We discuss possible extension of single crystal studies to serial femtosecond crystallography, particularly in view of the expected X-ray damage and ablation due to the first probe pulse. © 2015 Author(s).


Kurta R.P.,German Electron Synchrotron | Altarelli M.,European X ray Free Electronic Laser Facility | Weckert E.,German Electron Synchrotron | Vartanyants I.A.,German Electron Synchrotron | Vartanyants I.A.,National Research Nuclear University MEPhI
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

Angular x-ray cross-correlation analysis (XCCA) is an approach to study the structure of disordered systems using the results of coherent x-ray scattering experiments. Here, we present the results of simulations that validate our theoretical findings for XCCA obtained in a previous paper. We consider as a model two-dimensional (2D) disordered systems composed of noninteracting colloidal clusters with fivefold symmetry and with orientational and positional disorder. We simulate a coherent x-ray scattering in the far field from such disordered systems and perform the angular cross-correlation analysis of calculated diffraction data. The results of our simulations show the relation between the Fourier series representation of the cross-correlation functions (CCFs) and different types of correlations in disordered systems. The dependence of structural information extracted by XCCA on the density of disordered systems and the degree of orientational disorder of clusters is investigated. The statistical nature of the fluctuations of the CCFs in the model "single-shot" experiments is demonstrated and the potential of extracting structural information from the analysis of CCFs averaged over a large number of diffraction patterns is discussed. We also demonstrate the effect of partial coherence of the incident x-ray beams on the results of XCCA. © 2012 American Physical Society.


PubMed | European X Ray Free Electronic Laser Facility and Imperial College London
Type: Journal Article | Journal: Structural dynamics (Melville, N.Y.) | Year: 2016

In order to exploit the femtosecond pulse duration of X-ray Free-Electron Lasers (XFEL) operating in the hard X-ray regime for ultrafast time-resolved protein crystallography experiments, critical parameters that determine the crystallographic signal-to-noise (I/I) must be addressed. For single-crystal studies under low absorbed dose conditions, it has been shown that the intrinsic pulse intensity stability as well as mode structure and jitter of this structure, significantly affect the crystallographic signal-to-noise. Here, geometrical parameters are theoretically explored for a three-beam scheme: X-ray probe, optical pump, X-ray probe (or probe-pump-probe) which will allow experimental determination of the photo-induced structure factor amplitude differences, F, in a ratiometric manner, thereby internally referencing the intensity noise of the XFEL source. In addition to a non-collinear split-beam geometry which separates un-pumped and pumped diffraction patterns on an area detector, applying an additional convergence angle to both beams by focusing leads to integration over mosaic blocks in the case of well-ordered stationary protein crystals. Ray-tracing X-ray diffraction simulations are performed for an example using photoactive yellow protein crystals in order to explore the geometrical design parameters which would be needed. The specifications for an X-ray split and delay instrument that implements both an offset angle and focused beams are discussed, for implementation of a probe-pump-probe scheme at the European XFEL. We discuss possible extension of single crystal studies to serial femtosecond crystallography, particularly in view of the expected X-ray damage and ablation due to the first probe pulse.

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