Development of a hard X-ray split-and-delay line and performance simulations for two-color pump-probe experiments at the European XFEL

Lu, Wei; Friedrich, B.; Noll, T.; Zhou, Kaixiong; Hallmann, Jörg; Ansaldi, Gabriele; Roth, Thomas; Serkez, Svitozar; Geloni, Gianluca; Madsen, Anders; Eisebitt, Stefan

doi:10.1063/1.5027071

Cited by 52 publications

(31 citation statements)

References 45 publications

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“…It is common to model the aggregate effect of energybandwidth and mosaicity in a single Gaussian equation (Parkhurst, 2020, Chapter 5), yet diffBragg is a general framework. Notably, the work shown is directly applicable to two-color serial diffraction (Hara et al, 2013;Lu et al, 2018;Lutman et al, 2014) and pink-beam serial diffraction (Dejoie et al, 2013;Milne et al, 2017;Martin-Garcia et al, 2019) where indexing, refinement and data reduction protocols are in early development (Gevorkov et al, 2020). The work presented here assumed a perfect detector geometry; however, we demonstrated the robustness of diffBragg refinement to typical levels of detector panel displacement (see Section S3, Figs.…”

Section: Discussionmentioning

confidence: 65%

Beyond integration: modeling every pixel to obtain better structure factors from stills

Mendez

Bolotovsky

Bhowmick

et al. 2020

IUCrJ

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Most crystallographic data processing methods use pixel integration. In serial femtosecond crystallography (SFX), the intricate interaction between the reciprocal lattice point and the Ewald sphere is integrated out by averaging symmetrically equivalent observations recorded across a large number (104−106) of exposures. Although sufficient for generating biological insights, this approach converges slowly, and using it to accurately measure anomalous differences has proved difficult. This report presents a novel approach for increasing the accuracy of structure factors obtained from SFX data. A physical model describing all observed pixels is defined to a degree of complexity such that it can decouple the various contributions to the pixel intensities. Model dependencies include lattice orientation, unit-cell dimensions, mosaic structure, incident photon spectra and structure factor amplitudes. Maximum likelihood estimation is used to optimize all model parameters. The application of prior knowledge that structure factor amplitudes are positive quantities is included in the form of a reparameterization. The method is tested using a synthesized SFX dataset of ytterbium(III) lysozyme, where each X-ray laser pulse energy is centered at 9034 eV. This energy is 100 eV above the Yb3+ L-III absorption edge, so the anomalous difference signal is stable at 10 electrons despite the inherent energy jitter of each femtosecond X-ray laser pulse. This work demonstrates that this approach allows the determination of anomalous structure factors with very high accuracy while requiring an order-of-magnitude fewer shots than conventional integration-based methods would require to achieve similar results.

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Section: Discussionmentioning

confidence: 65%

Beyond integration: modeling every pixel to obtain better structure factors from stills

Mendez

Bolotovsky

Bhowmick

et al. 2020

IUCrJ

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“…We expect that our computational approach provides detailed atomic data for NLTE kinetic simulation tools, avoiding usage of standard IPD models based on LTE. It is worthwhile to note that the transient IP values reported here can be potentially measured by using singlecolor [80] and two-color [81] pump-probe schemes at XFEL facilities.…”

Section: Discussionmentioning

confidence: 99%

Transient ionization potential depression in nonthermal dense plasmas at high x-ray intensity

et al. 2021

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The advent of x-ray free-electron lasers (XFELs), which provide intense ultrashort x-ray pulses, has brought a new way of creating and analyzing hot and warm dense plasmas in the laboratory. Because of the ultrashort pulse duration, the XFEL-produced plasma will be out of equilibrium at the beginning, and even the electronic subsystem may not reach thermal equilibrium while interacting with a femtosecond timescale pulse. In the dense plasma, the ionization potential depression (IPD) induced by the plasma environment plays a crucial role for understanding and modeling microscopic dynamical processes. However, all theoretical approaches for IPD have been based on local thermal equilibrium (LTE), and it has been controversial to use LTE IPD models for the nonthermal situation. In this work, we propose a non-LTE (NLTE) approach to calculate the IPD effect by combining a quantum-mechanical electronic-structure calculation and a classical molecular dynamics simulation. This hybrid approach enables us to investigate the time evolution of ionization potentials and IPDs during and after the interaction with XFEL pulses, without the limitation of the LTE assumption. In our NLTE approach, the transient IPD values are presented as distributions evolving with time, which cannot be captured by conventional LTE-based models. The time-integrated ionization potential values are in good agreement with benchmark experimental data on solid-density aluminum plasma and other theoretical predictions based on LTE. The present work is promising to provide critical insights into nonequilibrium dynamics of dense plasma formation and thermalization induced by XFEL pulses.

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“…In this geometry, there would still be very high correlation possible between pumped and unpumped diffraction images, while still exploiting the diffract-before-destruct regime. While such an instrument would rely on a high performance split-and-delay line, 57 further instrumentation including microarrays of compound refractive lenses (CRLs) would also be needed for implementation. Nevertheless, with the potential to achieve orders of magnitude enhancement of difference measurement, this would be a route to develop the ability to measure nuclear coherence for protein crystallography specifically using low- or intermediate repetition rate accelerator technology.…”

Section: X-ray Source Parameters and Crystallographic Signal-to-noisementioning

confidence: 99%

Advances and opportunities in ultrafast X-ray crystallography and ultrafast structural optical crystallography of nuclear and electronic protein dynamics

Thor

2019

Structural Dynamics

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Both nuclear and electronic dynamics contribute to protein function and need multiple and complementary techniques to reveal their ultrafast structural dynamics response. Real-space information obtained from the measurement of electron density dynamics by X-ray crystallography provides aspects of both, while the molecular physics of coherence parameters and frequency-frequency correlation needs spectroscopy methods. Ultrafast pump-probe applications of protein dynamics in crystals provide real-space information through direct X-ray crystallographic structure analysis or through structural optical crystallographic analysis. A discussion of methods of analysis using ultrafast macromolecular X-ray crystallography and ultrafast nonlinear structural optical crystallography is presented. The current and future high repetition rate capabilities provided by X-ray free electron lasers for ultrafast diffraction studies provide opportunities for optical control and optical selection of nuclear coherence which may develop to access higher frequency dynamics through improvements of sensitivity and time resolution to reveal coherence directly. Specific selection of electronic coherence requires optical probes, which can provide real-space structural information through photoselection of oriented samples and specifically in birefringent crystals. Ultrafast structural optical crystallography of photosynthetic energy transfer has been demonstrated, and the theory of two-dimensional structural optical crystallography has shown a method for accessing the structural selection of electronic coherence.

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Development of a hard X-ray split-and-delay line and performance simulations for two-color pump-probe experiments at the European XFEL

Cited by 52 publications

References 45 publications

Beyond integration: modeling every pixel to obtain better structure factors from stills

Beyond integration: modeling every pixel to obtain better structure factors from stills

Transient ionization potential depression in nonthermal dense plasmas at high x-ray intensity

Advances and opportunities in ultrafast X-ray crystallography and ultrafast structural optical crystallography of nuclear and electronic protein dynamics

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