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

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 European XFEL, an upgrade project to equip the soft X-ray SASE3 beamline with a magnetic chicane is underway. In the present paper we describe the status of the project, its scientific focus and expected performance, including start-to-end simulations of the photon beam transport up to the sample, as well as recent experimental results demonstrating two-color lasing at photon energies of 805 eV + 835 eV and 910 eV + 950 eV. Additionally, we discuss methods to analyze the spectral properties and the intensity of the generated radiation to provide on-line diagnostics for future user experiments.

Download Full-text

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

New Journal of Physics ◽

10.1088/1367-2630/12/7/075002 ◽

2010 ◽

Vol 12 (7) ◽

pp. 075002 ◽

Cited By ~ 132

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

Download Full-text

Spectral monitoring at SwissFEL using a high-resolution on-line hard X-ray single-shot spectrometer

Journal of Synchrotron Radiation ◽

10.1107/s1600577521009619 ◽

2021 ◽

Vol 28 (6) ◽

Author(s):

Christian David ◽

Gediminas Seniutinas ◽

Mikako Makita ◽

Benedikt Rösner ◽

Jens Rehanek ◽

...

Keyword(s):

Free Electron ◽

Free Electron Laser ◽

Reference Data ◽

Diffraction Order ◽

Laser Pulses ◽

Single Shot ◽

Spectral Measurements ◽

X Ray ◽

On Line ◽

Spectral Monitoring

The performance and parameters of the online photon single-shot spectrometer (PSSS) at the Aramis beamline of the SwissFEL free-electron laser are presented. The device operates between the photon energies 4 and 13 keV and uses diamond transmission gratings and bent Si crystals for spectral measurements on the first diffraction order of the beam. The device has an energy window of 0.7% of the median photon energy of the free-electron laser pulses and a spectral resolution (full width at half-maximum) ΔE/E on the order of 10−5. The device was characterized by comparing its performance with reference data from synchrotron sources, and a parametric study investigated other effects that could affect the reliability of the spectral information.

Download Full-text

The photon beamline vacuum system of the European XFEL

Journal of Synchrotron Radiation ◽

10.1107/s1600577521005154 ◽

2021 ◽

Vol 28 (4) ◽

Author(s):

Martin Dommach ◽

Massimiliano Di Felice ◽

Bianca Dickert ◽

Denis Finze ◽

Janni Eidam ◽

...

Keyword(s):

Free Electron ◽

Free Electron Laser ◽

Vacuum System ◽

Entire System ◽

Scientific Instruments ◽

Beam Transport ◽

X Ray ◽

Laser Facility ◽

Reliability And Robustness ◽

Vacuum Systems

The photon beamline vacuum system of the European X-ray Free-Electron Laser Facility (European XFEL) is described. The ultra-large, in total more than 3 km-long, fan-like vacuum system, consisting of three photon beamlines is an essential part of the photon beam transport. It is located between the accelerator vacuum system and the scientific instruments. The main focus of the design was on the efficiency, reliability and robustness of the entire system to ensure the retention of beam properties and the operation of the X-ray optics and X-ray photon diagnostics components. Installation started in late 2014, the first of the three beamline vacuum systems was commissioned in spring 2017, and the last one was operational in mid-2018. The present state and experience from the first years of operation are outlined.

Download Full-text

The European X-ray Free-Electron Laser: toward an ultra-bright, high repetition-rate x-ray source

High Power Laser Science and Engineering ◽

10.1017/hpl.2015.17 ◽

2015 ◽

Vol 3 ◽

Cited By ~ 19

Author(s):

M. Altarelli

Keyword(s):

Free Electron ◽

Free Electron Laser ◽

Linear Accelerator ◽

High Repetition Rate ◽

Modes Of Operation ◽

X Ray ◽

High Repetition ◽

The Status ◽

Scientific Results ◽

Under Construction

The status of the European X-ray Free-Electron Laser (European XFEL), under construction near Hamburg, Germany, is described. The start of operations of the LCLS at SLAC and of SACLA in Japan has already produced impressive scientific results. The European XFEL facility is powered by a 17.5 GeV superconducting linear accelerator that, compared to these two operating facilities, will generate two orders of magnitude more pulses per second, up to 27 000. It can therefore support modes of operation switching the beam up to 30 times per second among three different experiments, providing each of them with thousands of pulses per second. The scientific possibilities opened up by these capabilities are briefly described, together with the current instrumental developments (in optics, detectors, lasers, etc.) that are necessary to implement this program.

Download Full-text

Slice collective dynamics, projected emittance deterioration and free electron laser performances detrimental effects

Journal of Plasma Physics ◽

10.1017/s0022377820001324 ◽

2020 ◽

Vol 86 (6) ◽

Author(s):

G. Dattoli ◽

S. Di Mitri ◽

F. Nguyen ◽

A. Petralia

Keyword(s):

Phase Space ◽

Output Power ◽

Free Electron ◽

Free Electron Laser ◽

Coherence Length ◽

Electron Bunch ◽

Laser Intensity ◽

Beam Transport ◽

X Ray ◽

Laser Dynamics

Self-amplified spontaneous emission (SASE) free electron laser (FEL) devices have disclosed an unexpected interplay between the laser intensity growth and regions of the electron bunch of the order of the coherence length. They are usually identified with the bunch slice and contribute to the laser dynamics with their own characteristics. The dynamical effects inducing geometrical and phase space misalignment of bunch slice in X-ray operating FELs can be traced back to a plethora of phenomena, both in the Linac accelerating section or inside the beam transport optic magnet. They are responsible for spoiling of the beam projected qualities and, if not corrected properly, induce an increase of the saturation length and a decreasing of the output power. We discuss the inclusion of these effects in models employing scaling formulae.

Download Full-text

X-ray photon diagnostics at the European XFEL

Journal of Synchrotron Radiation ◽

10.1107/s1600577519006611 ◽

2019 ◽

Vol 26 (5) ◽

pp. 1422-1431 ◽

Cited By ~ 7

Author(s):

Jan Grünert ◽

Marc Planas Carbonell ◽

Florian Dietrich ◽

Torben Falk ◽

Wolfgang Freund ◽

...

Keyword(s):

Free Electron ◽

Repetition Rate ◽

Free Electron Laser ◽

First Year ◽

X Rays ◽

Beam Transport ◽

Beam Position ◽

X Ray ◽

Time Period ◽

Beam Delivery

The European X-ray Free-Electron Laser (European XFEL) (Altarelli et al., 2006; Tschentscher et al., 2017), the world's largest and brightest X-ray free-electron laser (Saldin et al., 1999; Pellegrini et al., 2016), went into operation in 2017. This article describes the as-built realization of photon diagnostics for this facility, the diagnostics commissioning and their application for commissioning of the facility, and results from the first year of operation, focusing on the SASE1 beamline, which was the first to be commissioned. The commissioning consisted of pre-beam checkout, first light from the bending magnets, X-rays from single undulator segments, SASE tuning with many undulator segments, first lasing, optics alignment for FEL beam transport through the tunnel up to the experiment hutches, and finally beam delivery to first users. The beam properties assessed by photon diagnostics throughout these phases included per-pulse intensity, beam position, shape, lateral dimensions and spectral properties. During this time period, the machine provided users with up to 14 keV photon energy, 1.5 mJ pulse energy, 300 FEL pulses per train and 4.5 MHz intra-bunch train repetition rate at a 10 Hz train repetition rate. Finally, an outlook is given into the diagnostic prospects for the future.

Download Full-text

Compact hard X-ray split-and-delay line for studying ultrafast dynamics at free-electron laser sources

Journal of Synchrotron Radiation ◽

10.1107/s1600577519004570 ◽

2019 ◽

Vol 26 (4) ◽

pp. 1052-1057 ◽

Cited By ~ 4

Author(s):

Rustam Rysov ◽

Wojciech Roseker ◽

Michael Walther ◽

Gerhard Grübel

Keyword(s):

Free Electron ◽

Free Electron Laser ◽

Time Delays ◽

Delay Line ◽

Ultrafast Dynamics ◽

X Ray ◽

Continuous Energy ◽

On Line ◽

Laser Sources ◽

Performance Estimates

A compact hard X-ray split-and-delay line for studying ultrafast dynamics at free-electron laser sources is presented. The device is capable of splitting a single X-ray pulse into two fractions to introduce time delays from −5 to 815 ps with femtosecond resolution. The split-and-delay line can operate in a wide and continuous energy range between 7 and 16 keV. Compact dimensions of 60 × 60 × 30 cm with a total weight of about 60 kg make it portable and suitable for direct installation in an experimental hutch. The concept of the device is based on crystal diffraction. The piezo-driven stages utilized in the device give nanometre positioning accuracy. On-line monitoring systems based on X-ray cameras and intensity monitors are implemented to provide active alignment feedback. Performance estimates of the system are also presented.

Download Full-text

xcalib: a focal spot calibrator for intense X-ray free-electron laser pulses based on the charge state distributions of light atoms

Journal of Synchrotron Radiation ◽

10.1107/s1600577519003564 ◽

2019 ◽

Vol 26 (4) ◽

pp. 1017-1030 ◽

Cited By ~ 3

Author(s):

Koudai Toyota ◽

Zoltan Jurek ◽

Sang-Kil Son ◽

Hironobu Fukuzawa ◽

Kiyoshi Ueda ◽

...

Keyword(s):

Charge State ◽

Free Electron ◽

Free Electron Laser ◽

Focal Spot ◽

Experimental Results ◽

Experimental Conditions ◽

X Ray ◽

Wide Range ◽

Light Atoms ◽

Charge State Distributions

The xcalib toolkit has been developed to calibrate the beam profile of an X-ray free-electron laser (XFEL) at the focal spot based on the experimental charge state distributions (CSDs) of light atoms. Characterization of the fluence distribution at the focal spot is essential to perform the volume integrations of physical quantities for a quantitative comparison between theoretical and experimental results, especially for fluence-dependent quantities. The use of the CSDs of light atoms is advantageous because CSDs directly reflect experimental conditions at the focal spot, and the properties of light atoms have been well established in both theory and experiment. Theoretical CSDs are obtained using xatom, a toolkit to calculate atomic electronic structure and to simulate ionization dynamics of atoms exposed to intense XFEL pulses, which involves highly excited multiple core-hole states. Employing a simple function with a few parameters, the spatial profile of an XFEL beam is determined by minimizing the difference between theoretical and experimental results. The optimization procedure employing the reinforcement learning technique can automatize and organize calibration procedures which, before, had been performed manually. xcalib has high flexibility, simultaneously combining different optimization methods, sets of charge states, and a wide range of parameter space. Hence, in combination with xatom, xcalib serves as a comprehensive tool to calibrate the fluence profile of a tightly focused XFEL beam in the interaction region.

Download Full-text