scholarly journals Two- and Multi-bucket X-ray Free-Electron Laser at LCLS

2021 ◽  
Author(s):  
Franz-Josef Decker ◽  
Karl L. Bane ◽  
William Colocho ◽  
Sasha Gilevich ◽  
Agostino Marinelli ◽  
...  
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Single Pulse ◽  
Free Electron Lasers ◽  
Pulse Operation ◽  
Modes Of Operation ◽  
X Ray ◽  
Narrow Bandwidth ◽  
The One ◽  
Special Modes

Abstract X-ray Free Electron Lasers provide femtosecond X-ray pulses with narrow bandwidth and unprecedented peak brightness. Special modes of operation have been developed to deliver double pulses for X-ray pump, X-ray probe experiments. However, the longest delay between the two pulses achieved with existing single bucket methods is less than 1 picosecond, thus preventing exploration of longer timescales dynamics. We present a novel Two-bucket scheme covering delays from 350 picoseconds to hundreds of nanoseconds in discrete steps of 350 picoseconds. Performance for each pulse can be similar to the one in single pulse operation. The method has been experimentally tested with LCLS-I and LCLS-II hard x-ray undulators.

scholarly journals Switching of the harmonic order in free-electron lasers by controlling the density modulation of an electron bunch

2018 ◽  
Vol 25 (5) ◽  
pp. 1317-1322 ◽  
Author(s):  
Norihiro Sei ◽  
Hiroshi Ogawa ◽  
QiKa Jia
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Extreme Ultraviolet ◽  
Free Electron Lasers ◽  
Harmonic Order ◽  
Third Harmonic ◽  
X Ray ◽  
The Third ◽  
Density Modulation ◽  
Higher Harmonic

It was demonstrated that harmonic order in free-electron laser (FEL) oscillations could be switched by adjusting the dispersive gap of the optical klystron ETLOK-III in the storage ring NIJI-IV. The effective gains for the fundamental and third-harmonic FEL oscillations were evaluated and it was confirmed that the FEL oscillated at the order of the harmonic with the higher effective gain. The ratio between the effective gain for the fundamental and that for the third harmonic was controlled by the dispersive gap. It was also demonstrated that a spectral measurement of the FEL-based Compton scattering X-ray beam was effective for directly observing the switching of the harmonic order. These results contribute to the development of higher-harmonic FEL oscillations suppressing the fundamental FEL oscillation in the extreme ultraviolet and X-ray regions.

FREE-ELECTRON LASER SPECTROSCOPY OF SURFACES AND INTERFACES

1995 ◽  
Vol 02 (04) ◽  
pp. 501-512 ◽  
Author(s):  
N.H. TOLK ◽  
J.T. MCKINLEY ◽  
G. MARGARITONDO
Keyword(s):  
Synchrotron Radiation ◽  
Free Electron ◽  
Free Electron Laser ◽  
Interface Energy ◽  
Free Electron Lasers ◽  
Semiconductor Interface ◽  
X Ray ◽  
Surface And Interface ◽  
Surfaces And Interfaces ◽  
Radiation Sources

Synchrotron-radiation sources have become, since the late 1960’s, one of the fundamental experimental tools for surface and interface research. Only recently, however, a related type of photon sources - the free-electron lasers (FELs) — has begun to make important contributions to this field. For example, FELs have been used to reach unprecedented levels of accuracy and reliability in measuring semiconductor interface energy barriers. We review some of the present and proposed experiments that are made possible by the unmatched brightness and broad tunability of infrared FELs. Practical examples discussed in the review are supplied by our own programs at the Vanderbilt Free-Electron Laser. We also briefly analyze the possible future development of FELs and of their applications to surface and interface research, in particular, the possibility of x-ray FELs.

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.

scholarly journals Cryo-coherent diffractive imaging of biological samples with X-ray free-electron lasers

2016 ◽  
Vol 72 (2) ◽  
pp. 177-178
Author(s):  
Huaidong Jiang
Keyword(s):  
Biological Samples ◽  
Free Electron ◽  
Free Electron Laser ◽  
Free Electron Lasers ◽  
Diffractive Imaging ◽  
X Ray ◽  
Coherent Diffractive Imaging ◽  
Recent Developments

Recent developments in the imaging of biological samples using the X-ray free-electron laser at the SACLA facility are highlighted.

scholarly journals Electron-bunch lengthening on higher-harmonic oscillations in storage-ring free-electron lasers

2017 ◽  
Vol 24 (5) ◽  
pp. 912-918 ◽  
Author(s):  
Norihiro Sei ◽  
Hiroshi Ogawa ◽  
Shuichi Okuda
Keyword(s):  
Electron Beam ◽  
Storage Ring ◽  
Free Electron ◽  
Free Electron Laser ◽  
Cavity Length ◽  
Extreme Ultraviolet ◽  
Bunch Length ◽  
Free Electron Lasers ◽  
X Ray ◽  
Higher Harmonic

The influence of higher-harmonic free-electron laser (FEL) oscillations on an electron beam have been studied by measuring its bunch length at the NIJI-IV storage ring. The bunch length and the lifetime of the electron beam were measured, and were observed to have become longer owing to harmonic lasing, which is in accord with the increase of the FEL gain. It was demonstrated that the saturated FEL power could be described by the theory of bunch heating, even for the harmonic lasing. Cavity-length detuning curves were measured for the harmonic lasing, and it was found that the width of the detuning curve was proportional to a parameter that depended on the bunch length. These experimental results will be useful for developing compact resonator-type FELs by using higher harmonics in the extreme-ultraviolet and the X-ray regions.

Multi-colour pulses from seeded free-electron-lasers: towards the development of non-linear core-level coherent spectroscopies

2014 ◽  
Vol 171 ◽  
pp. 487-503 ◽  
Author(s):  
Filippo Bencivenga ◽  
Flavio Capotondi ◽  
Francesco Casolari ◽  
Francesco Dallari ◽  
Miltcho B. Danailov ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Free Electron ◽  
Free Electron Laser ◽  
Extreme Ultraviolet ◽  
Core Level ◽  
Wave Mixing ◽  
Free Electron Lasers ◽  
Diffraction Experiment ◽  
X Ray ◽  
Ultrafast Science

We report on new opportunities for ultrafast science thanks to the use of two-colour extreme ultraviolet (XUV) pulses at the FERMI free electron laser (FEL) facility. The two pulses have been employed to carry out a pioneering FEL-pump/FEL-probe diffraction experiment using a Ti target and tuning the FEL pulses to the M2/3-edge in order to explore the dependence of the dielectric constant on the excitation fluence. The future impact that the use of such a two-colour FEL emission will have on the development of ultrafast wave-mixing methods in the XUV/soft X-ray range is addressed and discussed.

scholarly journals An X-ray harmonic separator for next-generation synchrotron X-ray sources and X-ray free-electron lasers

2018 ◽  
Vol 25 (2) ◽  
pp. 346-353 ◽  
Author(s):  
Ichiro Inoue ◽  
Taito Osaka ◽  
Kenji Tamasaku ◽  
Haruhiko Ohashi ◽  
Hiroshi Yamazaki ◽  
...  
Keyword(s):  
Free Electron ◽  
Free Electron Laser ◽  
Grazing Incidence ◽  
Incidence Geometry ◽  
Photon Flux ◽  
Free Electron Lasers ◽  
Undulator Radiation ◽  
X Ray ◽  
Grazing Incidence Geometry ◽  
Selection Of

An X-ray prism for the extraction of a specific harmonic of undulator radiation is proposed. By using the prism in a grazing incidence geometry, the beam axes of fundamental and harmonics of undulator radiation are separated with large angles over 10 µrad, which enables the selection of a specific harmonic with the help of apertures, while keeping a high photon flux. The concept of the harmonic separation was experimentally confirmed using X-ray beams from the X-ray free-electron laser SACLA.

scholarly journals Systematic study of a corrugated waveguide as a microwave undulator

2019 ◽  
Vol 26 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Liang Zhang ◽  
Wenlong He ◽  
Jim Clarke ◽  
Kevin Ronald ◽  
Alan D. R. Phelps ◽  
...  
Keyword(s):  
Systematic Study ◽  
Free Electron ◽  
Free Electron Laser ◽  
Short Wavelength ◽  
Free Electron Lasers ◽  
Corrugated Waveguide ◽  
X Ray ◽  
Fast Estimation

Microwave undulators have great potential to be used in short-wavelength free-electron lasers. In this paper, the properties of a corrugated waveguide and its performance as an undulator cavity for a UK X-ray free-electron laser were systematically studied. The equations presented in this paper allow a fast estimation of the dimensions of the corrugated waveguide. An undulator cavity operating at 36 GHz designed for the HE11 and HE12 modes was investigated and the performance of both modes compared.

On-line monitoring of the spatial properties of hard X-ray free-electron lasers based on a grating splitter

2019 ◽  
Vol 26 (3) ◽  
pp. 619-628 ◽  
Author(s):  
Wenqiang Hua ◽  
Guangzhao Zhou ◽  
Zhe Hu ◽  
Shumin Yang ◽  
Keliang Liao ◽  
...  
Keyword(s):  
Free Electron ◽  
Incident Beam ◽  
Single Pulse ◽  
X Rays ◽  
Free Electron Lasers ◽  
Spatial Characteristics ◽  
X Ray ◽  
First Order ◽  
Spatial Properties ◽  
On Line

X-ray free-electron lasers (XFELs) play an increasingly important role in addressing the new scientific challenges relating to their high brightness, high coherence and femtosecond time structure. As a result of pulse-by-pulse fluctuations, the pulses of an XFEL beam may demonstrate subtle differences in intensity, energy spectrum, coherence, wavefront, etc., and thus on-line monitoring and diagnosis of a single pulse are required for many XFEL experiments. Here a new method is presented, based on a grating splitter and bending-crystal analyser, for single-pulse on-line monitoring of the spatial characteristics including the intensity profile, coherence and wavefront, which was suggested and applied experimentally to the temporal diagnosis of an XFEL single pulse. This simulation testifies that the intensity distribution, coherence and wavefront of the first-order diffracted beam of a grating preserve the properties of the incident beam, by using the coherent mode decomposition of the Gaussian–Schell model and Fourier optics. Indicatively, the first-order diffraction of appropriate gratings can be used as an alternative for on-line monitoring of the spatial properties of a single pulse without any characteristic deformation of the principal diffracted beam. However, an interesting simulation result suggests that the surface roughness of gratings will degrade the spatial characteristics in the case of a partially coherent incident beam. So, there exists a suitable roughness value for non-destructive monitoring of the spatial properties of the downstream beam, which depends on the specific optical path. Here, experiments based on synchrotron radiation X-rays are carried out in order to verify this method in principle. The experimental results are consistent with the theoretical calculations.

scholarly journals In vivo crystallography at X-ray free-electron lasers: the next generation of structural biology?

2014 ◽  
Vol 369 (1647) ◽  
pp. 20130497 ◽  
Author(s):  
François-Xavier Gallat ◽  
Naohiro Matsugaki ◽  
Nathan P. Coussens ◽  
Koichiro J. Yagi ◽  
Marion Boudes ◽  
...  
Keyword(s):  
Structural Biology ◽  
Free Electron ◽  
Free Electron Laser ◽  
Protein Crystal ◽  
X Ray ◽  
Sample Characterization ◽  
The One ◽  
Serial Femtosecond Crystallography

The serendipitous discovery of the spontaneous growth of protein crystals inside cells has opened the field of crystallography to chemically unmodified samples directly available from their natural environment. On the one hand, through in vivo crystallography, protocols for protein crystal preparation can be highly simplified, although the technique suffers from difficulties in sampling, particularly in the extraction of the crystals from the cells partly due to their small sizes. On the other hand, the extremely intense X-ray pulses emerging from X-ray free-electron laser (XFEL) sources, along with the appearance of serial femtosecond crystallography (SFX) is a milestone for radiation damage-free protein structural studies but requires micrometre-size crystals. The combination of SFX with in vivo crystallography has the potential to boost the applicability of these techniques, eventually bringing the field to the point where in vitro sample manipulations will no longer be required, and direct imaging of the crystals from within the cells will be achievable. To fully appreciate the diverse aspects of sample characterization, handling and analysis, SFX experiments at the Japanese SPring-8 angstrom compact free-electron laser were scheduled on various types of in vivo grown crystals. The first experiments have demonstrated the feasibility of the approach and suggest that future in vivo crystallography applications at XFELs will be another alternative to nano-crystallography.

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