Explanipedia

Single-shot sorting of Mössbauer time-domain data at X-ray free electron lasers Open

Miriam Gerharz, Willi Hippler, Berit Marx-Glowna, Sakshath Sadashivaiah, Kai S. Schulze , et al. · 2025

Mössbauer spectroscopy is widely used to study structure and dynamics of matter with remarkably high energy resolution, provided by the narrow nuclear resonance line widths. However, the narrow width implies low count rates, such that expe…

Lasing of a Cavity Based X-ray Source Open

Patrick Rauer, Immo Bahns, Bertram Friedrich, S. Casalbuoni, Massimiliano Di Felice , et al. · 2025

Cavity-based X-ray Free Electron Lasers (CBXFELs) promise to transform the field of hard X-ray science by delivering radiation with exceptional brilliance, stability, and full three-dimensional coherence. At the European XFEL, we have real…

Attosecond inner-shell lasing at ångström wavelengths Open

Thomas Linker, Aliaksei Halavanau, Thomas Kröll, Andrei Benediktovitch, Yu Zhang , et al. · 2025

Since the invention of the laser, nonlinear effects such as filamentation¹, Rabi cycling^2,3 and collective emission⁴ have been explored in the optical regime, leading to a wide range of scientific and indus…

Control of bandwidth and signal-to-noise ratio for hard-x-ray self-seeded free-electron lasers Open

Tianyun Long, Ye Chen, Winfried Decking, Gianluca Geloni, Marc Guetg , et al. · 2025

Hard-x-ray self-seeded (HXRSS) free-electron lasers (FELs) can provide nearly fully coherent radiation pulses in the hard-x-ray domain with extremely high spectral density, which opens up new possibilities for a wide range of scientific ap…

Updates on the Hard X-Ray Self-Seeding at the European XFEL Open

Shan Liu, Gianluca Geloni, Tianyun Long, Weilun Qin, Vitali Kocharyan , et al. · 2025

Terawatt-attosecond hard X-ray free-electron laser at high repetition rate Open

Jiawei Yan, Weilun Qin, Ye Chen, Winfried Decking, Philipp Dijkstal , et al. · 2024

Ångstrom and attosecond are the fundamental spatiotemporal scales for electron dynamics in various materials. Although attosecond pulses with wavelengths comparable to the atomic scales are expected to be a key tool in advancing attosecond…

Attosecond Inner-Shell Lasing at Angstrom Wavelengths Open

Thomas Linker, Aliaksei Halavanau, Thomas Kröll, Andrei Benediktovitch, Yu Zhang , et al. · 2024

Since the invention of the laser nonlinear effects such as filamentation, Rabi-cycling and collective emission have been explored in the optical regime leading to a wide range of scientific and industrial applications. X-ray free electron …

Capturing Nonlinear Electron Dynamics with Fully Characterised Attosecond X-ray Pulses Open

Lars Funke, Markus Ilchen, Kristina Dingel, Tommaso Mazza, Terry Mullins , et al. · 2024

Attosecond X-ray pulses are the key to studying electron dynamics at their natural timescale in specifically targeted electronic states. They promise to build the conceptual bridge between physical and chemical photo-reaction processes. Fr…

Crystal-based absolute photon energy calibration methods for hard x-ray free-electron lasers Open

Christian Grech, Marc Guetg, Gianluca Geloni, Ulrike Boesenberg, Naresh Kujala , et al. · 2024

Bragg diffraction from crystals is widely used to select a very narrow spectral range of x-ray pulses. The diffracted signal can be used to calibrate the photon energy, a fact that can be exploited very effectively at x-ray free-electron l…

Novel Photocathode Lasers for the Hard- and Soft-X-ray Free Electron Lasers EuXFEL and FLASH Open

Christoph Mahnke, Chen Li, Areeb Ahmed, Oender Akcaalan, Frank Brinker , et al. · 2024

We developed, constructed and commissioned novel photocathode lasers for the X-ray FELs European XFEL and FLASH which allow emittance optimization via beam shaping. Both facilities operate continuously with those lasers since Jan. 2024 wit…

Cascaded hard X-ray self-seeded free-electron laser at megahertz repetition rate Open

Shan Liu, Christian Grech, Marc Guetg, Suren Karabekyan, Vitali Kocharyan , et al. · 2023

High-resolution X-ray spectroscopy in the sub-nanosecond to femtosecond time range requires ultrashort X-ray pulses and a spectral X-ray flux considerably larger than that presently available. X-ray free-electron laser (XFEL) radiation fro…

Resonant X-ray excitation of the nuclear clock isomer 45Sc Open

Yuri Shvyd’ko, Ralf Röhlsberger, Оlga Kocharovskaya, Jörg Evers, Gianluca Geloni , et al. · 2023

Computer vision approaches for the absolute energy calibration of Bragg crystal setups Open

Christian Grech, Gianluca Geloni, Marc Guetg · 2023

Bragg crystals are widely used in free electron lasers to diffract and isolate an extremely narrow spectral range from the initial self-amplified spontaneous emission (SASE) signal. By rotating the crystal along one of its axes, multiple r…

Imaging via Correlation of X-Ray Fluorescence Photons Open

F. Trost, Kartik Ayyer, Mauro Prasciolu, Holger Fleckenstein, Miriam Barthelmeß , et al. · 2023

We demonstrate that x-ray fluorescence emission, which cannot maintain a stationary interference pattern, can be used to obtain images of structures by recording photon-photon correlations in the manner of the stellar intensity interferome…

Experimental Demonstration of Attoseconds-at-Harmonics at the SASE3 Undulator of the European XFEL Open

Andrei Trebushinin, Gianluca Geloni, Svitozar Serkez, Giuseppe Mercurio, Natalia Gerasimova , et al. · 2023

We report on observations of single spike spectra (3–13% of events) upon employing a previously proposed method for single spike generation via harmonic conversion. The method was tested at the soft X-ray SASE3 undulator of the European XF…

Cascaded hard X-ray self-seeded free-electron laser at MHz-repetition-rate Open

Shan Liu, Christian Grech, Marc Guetg, Suren Karabekyan, Vitali Kocharyan , et al. · 2023

The European XFEL is currently the only high-repetition rate hard X-ray free electron laser (FEL) facility in operation worldwide. We significantly improved its capabilities by installing a cascaded Hard X-ray Self-Seeding (HXRSS) system, …

Shot-to-shot two-dimensional photon intensity diagnostics within megahertz pulse-trains at the European XFEL Open

Trey Guest, Richard Bean, Johan Bielecki, Šarlota Birnšteinová, Gianluca Geloni , et al. · 2022

Characterizing the properties of X-ray free-electron laser (XFEL) sources is a critical step for optimization of performance and experiment planning. The recent availability of MHz XFELs has opened up a range of new opportunities for novel…

Revision of optical klystron enhancement effects in self-amplified spontaneous emission free electron lasers Open

Gianluca Geloni, Marc Guetg, Svitozar Serkez, E.A. Schneidmiller · 2021

We review the theory of optical klystrons, with its applications for self-amplified spontaneous emission free electron lasers in mind. We show that previous theories miss terms in the power gain factor that cannot be neglected, and we illu…

Frequency-Mixing Lasing Mode at European XFEL Open

Gianluca Geloni, Frank Brinker, Winfried Decking, Jan Grünert, Marc Guetg , et al. · 2021

We demonstrate generation of X-ray Free-Electron Laser (XFEL) pulses in frequency mixing mode at the SASE3 line of the European XFEL. The majority of the SASE3 FEL segments are tuned at two frequencies ω1 and ω2 following an alternate patt…

Experimental demonstration of two-color x-ray free-electron-laser pulses via wakefield excitation Open

S. Bettoni, P. Craievich, A. Dax, R. Ganter, Marc Guetg , et al. · 2021

Several beam manipulation methods have been studied and experimentally demonstrated to generate x-ray multipulses in free-electron-laser (FEL) facilities, advancing the fields of material science, molecular physics, and photochemistry by e…

Beam Loss Study for the Implementation of Dechirper at the European XFEL Open

Junjie Guo, Winfried Decking, Qiang Gu, Marc Guetg, Shan Liu , et al. · 2021

The European XFEL is a free-electron laser facility based on superconducting linac with high repetition rate up to 4.5 MHz. Wakefield structure (also called dechirper module) is planned to be installed in front of the SASE beam line at the…

Delay-detune scan for longitudinal electron beam characterization at free-electron lasers Open

Svitozar Serkez, Gianluca Geloni, Marc Guetg, Vitali Kocharyan, Shan Liu , et al. · 2020

We present first experimental results of a novel method to study the energy chirp of the electron beam lasing window at a free-electron laser operating in self-amplified spontaneous emission mode. The method requires a single magnetic chic…

Observation of Seeded Mn Stimulated X-Ray Emission Using Two-Color X-Ray Free-Electron Laser Pulses Open

Thomas Kröll, Clemens Weninger, Franklin D. Fuller, Marc Guetg, Andrei Benediktovitch , et al. · 2020

Kβ x-ray emission spectroscopy is a powerful probe for electronic structure analysis of 3d transition metal systems and their ultrafast dynamics. Selectively enhancing specific spectral regions would increase this sensitivity and provide f…

Opportunities for Two-Color Experiments in the Soft X-ray Regime at the European XFEL Open

Svitozar Serkez, Winfried Decking, L. Froehlich, Natalia Gerasimova, Jan Grünert , et al. · 2020

X-ray pump/X-ray probe applications are made possible at X-ray Free Electron Laser (XFEL) facilities by generating two X-ray pulses with different wavelengths and controllable temporal delay. In order to enable this capability at the Europ…

Simulation analysis and optimization of fresh-slice multistage free-electron lasers Open

Zhaoheng Guo, Marc Guetg, Yuantao Ding, Agostino Marinelli, Juhao Wu , et al. · 2020

The generation of femtosecond soft x-ray free-electron laser (XFEL) pulses with an energy of hundreds of microjoules has been demonstrated at the Linac Coherent Light Source (LCLS) based on fresh-slice multistage amplifications. In this pa…

Measurements of wake-induced electron beam deflection in a dechirper at the Linac Coherent Light Source Open

Johann Zemella, K. Bane, A. Fisher, Marc Guetg, Zhirong Huang , et al. · 2019

The RadiaBeam/SLAC dechirper, a structure consisting of pairs of flat, metallic, corrugated plates, has been installed just upstream of the undulators in the Linac Coherent Light Source (LCLS). As a dechirper, with the beam passing between…

XFEL Operational Flexibility due to the Dechirper System Open

Alberto Lutman, K. Bane, Yuantao Ding, Claudio Emma, Marc Guetg , et al. · 2019

The RadiaBeam/SLAC dechirper was installed to demonstrate the concept of using wakefields from a corrugated structure to change the energy profile along an electron bunch. Since installation, the system has allowed a large number of additi…

Study of XFEL Third Harmonic Radiation at LCLS Open

Claudio Emma, Marc Guetg, Aliaksei Halavanau, Alberto Lutman, Gabriel Marcus , et al. · 2019

In this paper, we focus on characterization of the nonlinear third harmonic radiation properties at Linac Coherent Light Source (LCLS). In addition, we experimentally perform third harmonic self-seeding, using diamond crystal attenuator in…

A simple method for a very short X-ray pulse production and attosecond diagnostic at LCLS Open

Alexander Novokhatski, Dorian Bohler, A. Brachmann, William Colocho, Franz-Josef Decker , et al. · 2018

Dispersion-Based Fresh-Slice Scheme for Free-Electron Lasers Open

Marc Guetg, Alberto Lutman, Yuantao Ding, T. Maxwell, Zhirong Huang · 2018

The fresh-slice technique improved the performance of several self-amplified spontaneous emission free-electron laser schemes by granting selective control on the temporal lasing slice without spoiling the other electron bunch slices. So f…

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