scholarly journals Emergence of anomalous dynamics in soft matter probed at the European XFEL

2020 ◽  
Vol 117 (39) ◽  
pp. 24110-24116 ◽  
Author(s):  
Felix Lehmkühler ◽  
Francesco Dallari ◽  
Avni Jain ◽  
Marcin Sikorski ◽  
Johannes Möller ◽  
...  
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Soft Matter ◽  
Correlation Spectroscopy ◽  
Laser Source ◽  
X Ray ◽  
High Fluences ◽  
Diffusion Dynamics ◽  
Diffraction Patterns ◽  
Soft Matter Physics

Dynamics and kinetics in soft matter physics, biology, and nanoscience frequently occur on fast (sub)microsecond but not ultrafast timescales which are difficult to probe experimentally. The European X-ray Free-Electron Laser (European XFEL), a megahertz hard X-ray Free-Electron Laser source, enables such experiments via taking series of diffraction patterns at repetition rates of up to 4.5 MHz. Here, we demonstrate X-ray photon correlation spectroscopy (XPCS) with submicrosecond time resolution of soft matter samples at the European XFEL. We show that the XFEL driven by a superconducting accelerator provides unprecedented beam stability within a pulse train. We performed microsecond sequential XPCS experiments probing equilibrium and nonequilibrium diffusion dynamics in water. We find nonlinear heating on microsecond timescales with dynamics beyond hot Brownian motion and superheated water states persisting up to 100 μs at high fluences. At short times up to 20 μs we observe that the dynamics do not obey the Stokes–Einstein predictions.

scholarly journals Comparison of EMC and CM methods for orienting diffraction images in single-particle imaging experiments

IUCrJ ◽  
2021 ◽  
Vol 8 (6) ◽  
Author(s):  
Miklós Tegze ◽  
Gábor Bortel
Keyword(s):  
Intensity Distribution ◽  
Single Particle ◽  
Free Electron ◽  
Free Electron Laser ◽  
Biological Molecules ◽  
Crucial Step ◽  
X Ray ◽  
Diffraction Patterns ◽  
Particle Imaging ◽  
Single Particle Imaging

In single-particle imaging (SPI) experiments, diffraction patterns of identical particles are recorded. The particles are injected into the X-ray free-electron laser (XFEL) beam in random orientations. The crucial step of the data processing of SPI is finding the orientations of the recorded diffraction patterns in reciprocal space and reconstructing the 3D intensity distribution. Here, two orientation methods are compared: the expansion maximization compression (EMC) algorithm and the correlation maximization (CM) algorithm. To investigate the efficiency, reliability and accuracy of the methods at various XFEL pulse fluences, simulated diffraction patterns of biological molecules are used.

STUDY OF TRANSVERSE EFFECTS IN THE PRODUCTION OF X-RAYS WITH A FREE-ELECTRON LASER BASED ON AN OPTICAL UNDULATOR

2007 ◽  
Vol 22 (23) ◽  
pp. 4270-4279
Author(s):  
A. BACCI ◽  
C. MAROLI ◽  
V. PETRILLO ◽  
L. SERAFNI ◽  
M. FERRARIO
Keyword(s):  
Electron Beam ◽  
Free Electron ◽  
Free Electron Laser ◽  
Laser Energy ◽  
Laser Pulses ◽  
Collective Effects ◽  
Laser Source ◽  
X Rays ◽  
X Ray ◽  
Back Scattering

The interaction between high-brilliance electron beams and counter-propagating laser pulses produces X rays via Thomson back-scattering. If the laser source is long and intense enough, the electrons of the beam can bunch and a regime of collective effects can establish. In this case of dominating collective effects, the FEL instability can develop and the system behaves like a free-electron laser based on an optical undulator. Coherent X-rays can be irradiated, with a bandwidth very much thinner than that of the corresponding incoherent emission. The emittance of the electron beam and the distribution of the laser energy are the principal quantities that limit the growth of the X-ray signal. In this work we analyse with a 3-D code the transverse effects in the emission produced by a relativistic electron beam when it is under the action of an optical laser pulse and the X-ray spectra obtained. The scalings typical of the optical wiggler, characterized by very short gain lengths and overall time durations of the process make possible considerable emission also with emittance of the order of 1mm mrad.

scholarly journals The FERMI@Elettra free-electron-laser source for coherent x-ray physics: photon properties, beam transport system and applications

2010 ◽  
Vol 12 (7) ◽  
pp. 075002 ◽  
Author(s):  
E Allaria ◽  
C Callegari ◽  
D Cocco ◽  
W M Fawley ◽  
M Kiskinova ◽  
...  
Keyword(s):  
Transport System ◽  
Free Electron ◽  
Free Electron Laser ◽  
Laser Source ◽  
Beam Transport ◽  
X Ray

scholarly journals Imaging ultrafast excited state pathways in transition metal complexes by X-ray transient absorption and scattering using X-ray free electron laser source

2016 ◽  
Vol 194 ◽  
pp. 639-658 ◽  
Author(s):  
Lin X. Chen ◽  
Megan L. Shelby ◽  
Patrick J. Lestrange ◽  
Nicholas E. Jackson ◽  
Kristoffer Haldrup ◽  
...  
Keyword(s):  
Excited State ◽  
Transition Metal ◽  
Free Electron ◽  
Free Electron Laser ◽  
Electronic Configuration ◽  
Laser Source ◽  
Relaxation Processes ◽  
Valence Orbital ◽  
X Ray ◽  
Orbital Energies

This report will describe our recent studies of transition metal complex structural dynamics on the fs and ps time scales using an X-ray free electron laser source, Linac Coherent Light Source (LCLS). Ultrafast XANES spectra at the Ni K-edge of nickel(ii) tetramesitylporphyrin (NiTMP) were measured for optically excited states at a timescale from 100 fs to 50 ps, providing insight into its sub-ps electronic and structural relaxation processes. Importantly, a transient reduced state Ni(i) (π, 3dx2−y2) electronic state is captured through the interpretation of a short-lived excited state absorption on the low-energy shoulder of the edge, which is aided by the computation of X-ray transitions for postulated excited electronic states. The observed and computed inner shell to valence orbital transition energies demonstrate and quantify the influence of the electronic configuration on specific metal orbital energies. A strong influence of the valence orbital occupation on the inner shell orbital energies indicates that one should not use the transition energy from 1s to other orbitals to draw conclusions about the d-orbital energies. For photocatalysis, a transient electronic configuration could influence d-orbital energies up to a few eV and any attempt to steer the reaction pathway should account for this to ensure that external energies can be used optimally in driving desirable processes. NiTMP structural evolution and the influence of the porphyrin macrocycle conformation on relaxation kinetics can be likewise inferred from this study.

scholarly journals Data processing software suiteSITENNOfor coherent X-ray diffraction imaging using the X-ray free-electron laser SACLA

2014 ◽  
Vol 21 (3) ◽  
pp. 600-612 ◽  
Author(s):  
Yuki Sekiguchi ◽  
Tomotaka Oroguchi ◽  
Yuki Takayama ◽  
Masayoshi Nakasako
Keyword(s):  
Data Processing ◽  
Free Electron ◽  
Free Electron Laser ◽  
Single Shot ◽  
X Ray Diffraction ◽  
X Ray ◽  
Custom Made ◽  
Diffraction Imaging ◽  
Diffraction Patterns ◽  
Ccd Detectors

Coherent X-ray diffraction imaging is a promising technique for visualizing the structures of non-crystalline particles with dimensions of micrometers to sub-micrometers. Recently, X-ray free-electron laser sources have enabled efficient experiments in the `diffraction before destruction' scheme. Diffraction experiments have been conducted at SPring-8 Angstrom Compact free-electron LAser (SACLA) using the custom-made diffraction apparatus KOTOBUKI-1 and two multiport CCD detectors. In the experiments, ten thousands of single-shot diffraction patterns can be collected within several hours. Then, diffraction patterns with significant levels of intensity suitable for structural analysis must be found, direct-beam positions in diffraction patterns determined, diffraction patterns from the two CCD detectors merged, and phase-retrieval calculations for structural analyses performed. A software suite namedSITENNOhas been developed to semi-automatically apply the four-step processing to a huge number of diffraction data. Here, details of the algorithm used in the suite are described and the performance for approximately 9000 diffraction patterns collected from cuboid-shaped copper oxide particles reported. Using theSITENNOsuite, it is possible to conduct experiments with data processing immediately after the data collection, and to characterize the size distribution and internal structures of the non-crystalline particles.

scholarly journals The Effect of Intensity Fluctuations on Sequential X-ray Photon Correlation Spectroscopy at the X-ray Free Electron Laser Facilities

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1109
Author(s):  
Yue Cao ◽  
Dina Sheyfer ◽  
Zhang Jiang ◽  
Siddharth Maddali ◽  
Hoydoo You ◽  
...  
Keyword(s):  
Time Scales ◽  
Free Electron ◽  
Free Electron Laser ◽  
Photon Correlation Spectroscopy ◽  
Signal To Noise Ratio ◽  
Correlation Spectroscopy ◽  
Signal To Noise ◽  
Photon Correlation ◽  
X Ray ◽  
Intensity Fluctuations

How materials evolve at thermal equilibrium and under external excitations at small length and time scales is crucial to the understanding and control of material properties. X-ray photon correlation spectroscopy (XPCS) at X-ray free electron laser (XFEL) facilities can in principle capture dynamics of materials that are substantially faster than a millisecond. However, the analysis and interpretation of XPCS data is hindered by the strongly fluctuating X-ray intensity from XFELs. Here we examine the impact of pulse-to-pulse intensity fluctuations on sequential XPCS analysis. We show that the conventional XPCS analysis can still faithfully capture the characteristic time scales, but with substantial decrease in the signal-to-noise ratio of the g2 function and increase in the uncertainties of the extracted time constants. We also demonstrate protocols for improving the signal-to-noise ratio and reducing the uncertainties.

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