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 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.

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.

Free-electron laser multiplex driven by a superconducting linear accelerator

2016 ◽  
Vol 23 (5) ◽  
pp. 1070-1075 ◽  
Author(s):  
Tim Plath ◽  
Philipp Amstutz ◽  
Jörn Bödewadt ◽  
Günter Brenner ◽  
Nagitha Ekanayake ◽  
...  
Keyword(s):  
Research And Development ◽  
Free Electron ◽  
Free Electron Laser ◽  
Linear Accelerator ◽  
Extreme Ultraviolet ◽  
Free Electron Lasers ◽  
X Ray ◽  
User Facility ◽  
20 Nm ◽  
Simultaneous Lasing

Free-electron lasers (FELs) generate femtosecond XUV and X-ray pulses at peak powers in the gigawatt range. The FEL user facility FLASH at DESY (Hamburg, Germany) is driven by a superconducting linear accelerator with up to 8000 pulses per second. Since 2014, two parallel undulator beamlines, FLASH1 and FLASH2, have been in operation. In addition to the main undulator, the FLASH1 beamline is equipped with an undulator section, sFLASH, dedicated to research and development of fully coherent extreme ultraviolet photon pulses using external seed lasers. In this contribution, the first simultaneous lasing of the three FELs at 13.4 nm, 20 nm and 38.8 nm is presented.

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.

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 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.

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