scholarly journals X-ray photon diagnostics at the European XFEL

2019 ◽  
Vol 26 (5) ◽  
pp. 1422-1431 ◽  
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.

scholarly journals High Repetition Rate and Coherent Free-Electron Laser in the X-Rays Range Tailored for Linear Spectroscopy

Instruments ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 47 ◽  
Author(s):  
Vittoria Petrillo ◽  
Michele Opromolla ◽  
Alberto Bacci ◽  
Illya Drebot ◽  
Giacomo Ghiringhelli ◽  
...  
Keyword(s):  
Free Electron ◽  
Repetition Rate ◽  
Free Electron Laser ◽  
Extreme Ultraviolet ◽  
High Harmonic ◽  
High Repetition Rate ◽  
X Rays ◽  
Regenerative Amplifier ◽  
X Ray ◽  
High Repetition

Fine time-resolved analysis of matter—i.e., spectroscopy and photon scattering—in the linear response regime requires fs-scale pulsed, high repetition rate, fully coherent X-ray sources. A seeded Free Electron Laser (FEL) driven by a Linac based on Super Conducting cavities, generating 10 8 – 10 10 coherent photons at 2–5 keV with 0.2–1 MHz of repetition rate, can address this need. Three different seeding schemes, reaching the X-ray range, are described hereafter. The first two are multi-stage cascades upshifting the radiation frequency by a factor of 10–30 starting from a seed represented by a coherent flash of extreme ultraviolet light. This radiation can be provided either by the High Harmonic Generation of an optical laser or by an FEL Oscillator operating at 12–14 nm. The third scheme is a regenerative amplifier working with X-ray mirrors. The whole chain of the X-ray generation is here described by means of start-to-end simulations.

scholarly journals Nanofocusing Optics for an X-Ray Free-Electron Laser Generating an Extreme Intensity of 100 EW/cm2 Using Total Reflection Mirrors

2020 ◽  
Vol 10 (7) ◽  
pp. 2611
Author(s):  
Hirokatsu Yumoto ◽  
Yuichi Inubushi ◽  
Taito Osaka ◽  
Ichiro Inoue ◽  
Takahisa Koyama ◽  
...  
Keyword(s):  
Photon Energy ◽  
Pulse Energy ◽  
Free Electron ◽  
Free Electron Laser ◽  
Total Reflection ◽  
Experimental Chamber ◽  
X Rays ◽  
X Ray ◽  
Set Up ◽  
Focused Beam

A nanofocusing optical system—referred to as 100 exa—for an X-ray free-electron laser (XFEL) was developed to generate an extremely high intensity of 100 EW/cm2 (1020 W/cm2) using total reflection mirrors. The system is based on Kirkpatrick-Baez geometry, with 250-mm-long elliptically figured mirrors optimized for the SPring-8 Angstrom Compact Free-Electron Laser (SACLA) XFEL facility. The nano-precision surface employed is coated with rhodium and offers a high reflectivity of 80%, with a photon energy of up to 12 keV, under total reflection conditions. Incident X-rays on the optics are reflected with a large spatial acceptance of over 900 μm. The focused beam is 210 nm × 120 nm (full width at half maximum) and was evaluated at a photon energy of 10 keV. The optics developed for 100 exa efficiently achieved an intensity of 1 × 1020 W/cm2 with a pulse duration of 7 fs and a pulse energy of 150 μJ (25% of the pulse energy generated at the light source). The experimental chamber, which can provide different stage arrangements and sample conditions, including vacuum environments and atmospheric-pressure helium, was set up with the focusing optics to meet the experimental requirements.

scholarly journals Liquid sample delivery techniques for serial femtosecond crystallography

2014 ◽  
Vol 369 (1647) ◽  
pp. 20130337 ◽  
Author(s):  
Uwe Weierstall
Keyword(s):  
Flow Rate ◽  
Free Electron ◽  
Repetition Rate ◽  
Free Electron Laser ◽  
Room Temperature ◽  
Liquid Flow Rate ◽  
Free Electron Lasers ◽  
Liquid Sample ◽  
X Ray ◽  
Serial Femtosecond Crystallography

X-ray free-electron lasers overcome the problem of radiation damage in protein crystallography and allow structure determination from micro- and nanocrystals at room temperature. To ensure that consecutive X-ray pulses do not probe previously exposed crystals, the sample needs to be replaced with the X-ray repetition rate, which ranges from 120 Hz at warm linac-based free-electron lasers to 1 MHz at superconducting linacs. Liquid injectors are therefore an essential part of a serial femtosecond crystallography experiment at an X-ray free-electron laser. Here, we compare different techniques of injecting microcrystals in solution into the pulsed X-ray beam in vacuum. Sample waste due to mismatch of the liquid flow rate to the X-ray repetition rate can be addressed through various techniques.

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 Perspectives towards Sub-Ångström Working Regime of the European X-ray Free-Electron Laser with Low-Emittance Electron Beams

2021 ◽  
Vol 11 (22) ◽  
pp. 10768
Author(s):  
Ye Chen ◽  
Frank Brinker ◽  
Winfried Decking ◽  
Matthias Scholz ◽  
Lutz Winkelmann
Keyword(s):  
Electron Beam ◽  
Photon Energy ◽  
Free Electron ◽  
Free Electron Laser ◽  
Electron Beams ◽  
Energy Levels ◽  
Energetic Electron ◽  
X Rays ◽  
X Ray ◽  
Low Emittance

Sub-ångström working regime refers to a working state of free-electron lasers which allows the generation of hard X-rays at a photon wavelength of 1 ångström and below, that is, a photon energy of 12.5 keV and above. It is demonstrated that the accelerators of the European X-ray Free-Electron Laser can provide highly energetic electron beams of up to 17.5 GeV. Along with long variable-gap undulators, the facility offers superior conditions for exploring self-amplified spontaneous emission (SASE) in the sub-ångström regime. However, the overall FEL performance relies quantitatively on achievable electron beam qualities through a kilometers-long accelerator beamline. Low-emittance electron beam production and the associated start-to-end beam physics thus becomes a prerequisite to dig in the potentials of SASE performance towards higher photon energies. In this article, we present the obtained results on electron beam qualities produced with different accelerating gradients of 40 MV/m–56 MV/m at the cathode, as well as the final beam qualities in front of the undulators via start-to-end simulations considering realistic conditions. SASE studies in the sub-ångström regime, using optimized electron beams, are carried out at varied energy levels according to the present state of the facility, that is, a pulsed mode operating with a 10 Hz-repetition 0.65 ms-long bunch train energized to 14 GeV and 17.5 GeV. Millijoule-level SASE intensity is obtained at a photon energy of 25 keV at 14 GeV electron beam energy using a gain length of about 7 m. At 17.5 GeV, half-millijoule lasing is achieved at 40 keV. Lasing at up to 50 keV is demonstrated with pulse energies in the range of a few hundreds and tens of microjoules with existing undulators and currently achievable electron beam qualities.

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