A5032964532- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Advanced X-ray Imaging Techniques
- Laser-Plasma Interactions and Diagnostics
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Laser-Matter Interactions and Applications
- Gyrotron and Vacuum Electronics Research
- Particle Detector Development and Performance
- High-Energy Particle Collisions Research
- X-ray Diffraction in Crystallography
- Advanced Fiber Laser Technologies
- Crystallization and Solubility Studies
- Plasma Diagnostics and Applications
- Laser-induced spectroscopy and plasma
- Laser Design and Applications
- Spectroscopy and Quantum Chemical Studies
- Magnetic confinement fusion research
- Advanced Electron Microscopy Techniques and Applications
- Atomic and Subatomic Physics Research
- Photoreceptor and optogenetics research
- Photochemistry and Electron Transfer Studies
- Superconducting Materials and Applications
- Astrophysics and Cosmic Phenomena
- Photonic and Optical Devices
Deutsches Elektronen-Synchrotron DESY
2012-2022
Universität Hamburg
2014-2022
University College London
2022
University of Strathclyde
2022
Cockcroft Institute
2022
Siemens Healthcare (Germany)
2019
University of Cologne
2017
Walter de Gruyter (Germany)
2014
Institut für Automatisierung und Informatik
2014
Menlo Systems (Germany)
2007-2014
The following topics are dealt with: TTF/FLASH in the XFEL context, general layout of facility, accelerator, undulators for SAES and spontaneous emission, photon beamlines scientific instruments, infrastructure auxiliary systems, commissioning operation, project management organization, cost time schedule. (HSI)
The electro-optic (EO) effect is a powerful diagnostic tool for determining the time profile of ultrashort relativistic electron bunches. When bunch passes within few mm an crystal, its transient electric field equivalent to half-cycle THz pulse passing through crystal. induced birefringence can be detected with polarized femtosecond laser pulses. A simulation code has been written in order understand faithfulness and limitations shape reconstruction by EO sampling. are propagated as wave...
Coherent transition radiation (CTR) in the THz regime is an important diagnostic tool for analyzing temporal structure of ultrashort electron bunches needed ultraviolet and x-ray free-electron lasers. It also a powerful source such radiation, covering exceptionally broad frequency range from about 200 GHz to 100 THz. At soft laser FLASH we have installed beam transport channel (TR) with intention guide large fraction laboratory outside accelerator tunnel. The produced on screen inside...
A tunable plasma-based energy dechirper has been developed at FLASHForward to remove the correlated spread of a 681 MeV electron bunch. Through interaction bunch with wakefields excited in plasma projected was reduced from FWHM 1.31% 0.33% without reducing stability incoming beam. The experimental results for variable density are good agreement analytic predictions and three-dimensional simulations. proof-of-principle dechirping strength 1.8 GeV/mm/m significantly exceeds those demonstrated...
Energy-efficient plasma-wakefield acceleration of particle bunches with low energy spread is a promising path to realizing compact free-electron lasers and colliders. High efficiency can be achieved simultaneously by strong beam loading plasma wakefields when accelerating carefully tailored current profiles [M. Tzoufras et al., Phys. Rev. Lett. 101, 145002 (2008)]. We experimentally demonstrate such optimal in nonlinear electron-driven accelerator. Bunches an initial 1 GeV were accelerated...
The longitudinal profiles of ultrashort relativistic electron bunches at the soft x-ray free-electron laser FLASH have been investigated using two single-shot detection schemes: an electro-optic (EO) detector measuring Coulomb field bunch and a radio-frequency structure transforming charge distribution into transverse streak. A comparison permits absolute calibration EO technique. signals as short 60 fs (rms) observed, which is new record in single close to limit given by material properties.
High-gain free-electron lasers (FELs) in the ultraviolet and x-ray regime put stringent demands on peak current, transverse emittance, energy spread of driving electron beam. At soft FEL FLASH, a deflecting microwave structure (TDS) has been installed to determine these parameters for longitudinally compressed bunches, which are characterized by narrow leading high charge density long tail. The rapidly varying electromagnetic field TDS deflects electrons vertically transforms time profile...
High-gain free-electron lasers (FELs) are capable of generating femtosecond x-ray pulses with peak brilliances many orders magnitude higher than at other existing sources. In order to fully exploit the opportunities offered by these light in time-resolved experiments, an unprecedented synchronization accuracy is required. this Letter, we distributed pulse train a mode-locked fiber laser stability different locations linear accelerator soft FEL FLASH. A novel electro-optic detection scheme...
Precise measurements of the temporal profile ultrashort electron bunches are high interest for optimization and operation ultraviolet x-ray free-electron lasers. The electro-optic (EO) technique has been applied a single-shot direct visualization time individual at FLASH. This paper presents thorough description experimental setup results. An absolute calibration EO performed utilizing simultaneous with transverse-deflecting radio-frequency structure that transforms longitudinal bunch charge...
One of the most challenging tasks for extreme ultraviolet, soft and hard x-ray free-electron laser photon diagnostics is precise determination pulse duration, which typically in sub 100 fs range. Nine different methods, able to determine such ultrashort durations, were compared experimentally at FLASH, self-amplified spontaneous emission DESY Hamburg, order identify advantages disadvantages methods. Radiation pulses a wavelength 13.5 24.0 nm together with corresponding electron bunch...
The ultrafast photoisomerization of a push−pull substituted azobenzene (4-nitro-4'-(dimethylamino)azobenzene, NA) is studied by means femtosecond fluorescence and absorption spectroscopy. dynamics biphasic. initial with narrow intense spectrum decays in ∼100 fs. This decay accompanied the rise broad red-shifted much weaker emission. same time constants recur transient spectra which hold additional information on ground-state dynamics. ground state recovers 0.8 ps, demonstrating that only...
Terahertz (THz) pulses with energies up to 100 μJ and corresponding electric fields 1 MV/cm were generated by coherent transition radiation from 500 MeV electron bunches at the free-electron laser Freie-Elektronen-Laser in Hamburg (FLASH). The characterized time domain electro-optical sampling a synchronized femtosecond jitter of less than fs. High THz field strengths quality synchronization an optical will enable observation nonlinear phenomena.
The successful operation of X-ray free-electron lasers (FELs), like the Linac Coherent Light Source or Free-Electron Laser in Hamburg (FLASH), makes unprecedented research on matter at atomic length and ultrafast time scales possible. However, order to take advantage these unique light sources meet strict requirements many experiments photon science, FEL pulse durations need be known tunable. This can achieved by controlling driving electron beams, high-resolution longitudinal beam...
We present single-shot measurements of the longitudinal bunch profile from a laser-wakefield accelerator with sub-fs resolution, based on detection coherent transition radiation in broad spectral range. A previously developed phase retrieval algorithm enables reconstruction without prior assumptions about its shape. In this study, variable-length gas target is used to explore dynamics evolution. Our results show that once laser energy depleted time structure generated electron beam changes...
The formation and quenching of the triplet state xanthone are studied by femtosecond techniques. As revealed fluorescence spectroscopy, primarily excited 1ππ* decays within 1.5 ps. In a transient absorption experiment, this time constant is associated with partial rise signature. This has second slower component 12 presence high concentrations quencher 1-methylnaphthalene, slow ps absent. finding gives strong evidence that biphasic due to sequential mechanism, namely, 1ππ * → 3nπ* fast...