A5027728986- Particle Accelerators and Free-Electron Lasers
- Advanced X-ray Imaging Techniques
- Particle accelerators and beam dynamics
- Gyrotron and Vacuum Electronics Research
- Superconducting Materials and Applications
- Advanced Electron Microscopy Techniques and Applications
- Laser-Plasma Interactions and Diagnostics
- Adrenal and Paraganglionic Tumors
- Planetary Science and Exploration
- Semiconductor materials and interfaces
- Silicon Nanostructures and Photoluminescence
- Space Science and Extraterrestrial Life
- Astro and Planetary Science
- Laser Design and Applications
- Thin-Film Transistor Technologies
- Plant Ecology and Taxonomy Studies
- Aquaculture disease management and microbiota
- Reproductive biology and impacts on aquatic species
- Botanical Studies and Applications
- Atomic and Subatomic Physics Research
- Photocathodes and Microchannel Plates
- Spaceflight effects on biology
- Radiation Therapy and Dosimetry
- Geological and Geochemical Analysis
- Nanowire Synthesis and Applications
Deutsches Elektronen-Synchrotron DESY
2021-2025
Delft University of Technology
2022-2024
Utrecht University
2022
Lund University
2020-2021
Uppsala University
2021
Peking University
2001-2019
National Synchrotron Radiation Research Center
2019
MAX IV Laboratory
2019
SLAC National Accelerator Laboratory
2017-2018
Menlo School
2017
Resonant oscillators with stable frequencies and large quality factors help us to keep track of time high precision. Examples range from quartz crystal in wristwatches atomic clocks, which are, at present, our most precise measurement devices1. The search for more convenient reference is continuing2-6. Nuclear are better than because their naturally higher resilience against external perturbations7-9. One the promising cases an ultra-narrow nuclear resonance transition 45Sc between ground...
Abstract High-resolution X-ray spectroscopy in the sub-nanosecond to femtosecond time range requires ultrashort pulses and a spectral flux considerably larger than that presently available. free-electron laser (XFEL) radiation from hard self-seeding (HXRSS) setups has been demonstrated past offers necessary peak properties. So far, these systems could not provide high repetition rates enabling average flux. We report results for cascaded HXRSS system installed at European XFEL, currently...
Hard-x-ray self-seeded (HXRSS) free-electron lasers (FELs) can provide nearly fully coherent radiation pulses in the hard-x-ray domain with extremely high spectral density, which opens up new possibilities for a wide range of scientific applications such as resonant inelastic x-ray scattering, nuclear resonance and Raman spectroscopy. Spectral bandwidth signal-to-noise ratio (SNR) are two important parameters seeded FELs. Our theoretical experimental studies demonstrate that SNR HXRSS FELs...
Abstract Ångstrom and attosecond are the fundamental spatiotemporal scales for electron dynamics in various materials. Although pulses with wavelengths comparable to atomic expected be a key tool advancing science, producing high-power hard X-ray at ångstrom remains formidable challenge. Here, we report generation of terawatt-scale using free-electron laser special operation mode. We achieved 9 keV single-spike mean pulse energy around 180 μJ, exceeding previous reports by more than an order...
Two-color high intensity x-ray free-electron lasers (FELs) provide powerful tools for probing ultrafast dynamic systems. A novel concept of realizing fresh-slice two-color lasing through slice-dependent transverse mismatch has been proposed by one the authors [Y. Chao, SLAC Report No. SLAC-PUB-16935, 2016]. In this paper we present a feasible example following based on Linac Coherent Light Source parameters. Time-dependent along bunch is generated passive dechirper module and controlled...
Time-resolved diagnostics at free-electron laser (FEL) facilities, in particular electron beam longitudinal phase space (LPS) and FEL power profile measurements, provide information highly valuable for users, machine development studies, setup. We investigate the slice energy resolution of passive streaker setups, effect an chirp on measured spread. Downstream hard x-ray SASE2 beamline European XFEL, these measurements are enabled by a single-plate nonmovable wakefield streaker, essentially...
We demonstrated selective slice-dependent lasing by controlling the matching to undulator of different slices within an electron bunch. The mismatch was realized through quadrupole wakefield generated in a corrugated structure. A deterministic procedure based on empirical beam transport and phase space information is used match selected turns lase while keeping all other from lasing, thus staying fresh. Measurements time-resolved bunch energy loss transverse deflecting cavity confirmed...
An X-ray free-electron laser oscillator (XFELO) is a new type of hard source that would produce fully coherent pulses with meV bandwidth and stable intensity. The XFELO complements existing sources based on self-amplified spontaneous emission (SASE) from high-gain lasers (XFEL) ultra-short broad-band chaotic spectra. This report discussions scientific opportunities enabled by an during workshop held at SLAC June 29 - July 1, 2016
Abstract Minimizing projected emittance of high brightness electron beam is important for efficient overlap between and radiation pulse in an FEL facility. Coherent synchrotron (CSR) emission a single bending section the transport system usually introduces different slice energy modulation hence transverse kicks designed dispersion-free lattice, causing growth. Here we present theoretical simulation study CSR effect on growth switchyard arc before SASE2 undulator beamline at European XFEL....
Microbunching instability (MBI) has been one of the most challenging issues in designs high-brightness beam transport lines for single-pass or recirculating accelerators. Although intrabeam scattering (IBS) long studied lepton hadron storage rings as a slow diffusion process high-intensity proton linear accelerators mechanism halo, effects IBS on electron have drawn attention only recent two decades due to emergence linac-based energy-recovery-linac-based fourth-generation light sources,...
We study a self-seeded high-gain harmonic generation (HGHG) free-electron laser (FEL) scheme to extend the wavelength of soft X-ray FEL. This uses regular self-seeding monochromator generate seed at 1.52 nm, followed by HGHG configuration produce coherent, narrow-bandwidth radiations GW level. The 2nd and 3rd radiation is investigated with start-to-end simulations. Detailed studies FEL performance shot-to-shot fluctuations are presented.
In this paper the design of free-electron laser (FEL) in SXL (Soft X-ray Laser) project at MAX IV Laboratory is presented. The target performance parameters originate a science case put forward by Swedish users and FEL foreseen to be driven existing 3 GeV linac. planned realized different stages focus on Phase 1, where basic operation mode for will SASE (self-amplified spontaneous emission), with an emphasis short pulses. Simulation results two linac bunches (high low charge) pulse duration...
We present analytical and numerical studies of short-range wakefields in an L-shaped corrugated structure. This structure has variable streaking polarization the quadrupole wakefield component is suppressed when beam moves with equal distances to both plates. These features provide promising capability multidimensional phase space diagnostic fresh-slice applications. first give zeroth-order expressions longitudinal transverse wake functions using conformal mapping method. Then we combine...
The studies of incoherent single-particle and collective multi-particle effects are, in general, separated accelerator beam dynamics that the two dynamical phenomena involve quite different time scales. Recent experimental measurements indicate some parameter regime, small-angle, multiple scattering within a high-brightness electron can have strong influence on microbunched dynamics. In this paper, we apply our recently developed semi-analytical kinetic analysis to investigate phase space...
The microbunching instability driven by beam collective effects in a linear accelerator of free-electron laser (FEL) facility significantly degrades the electron quality and FEL performance. A conventional method to suppress this is introduce an additional uncorrelated energy spread laser-electron interaction, which has been successfully operated Linac Coherent Light Source Fermi@Elettra, etc. Some other ideas are recently proposed without increasing spread, could benefit seeded schemes. In...
Abstract The European XFEL is currently the only high-repetition rate hard X-ray free electron laser (FEL) facility in operation worldwide. We significantly improved its capabilities by installing a cascaded Hard Self-Seeding (HXRSS) system, composed of two single-crystal monochromators. With this mJ-level pulses photon energy range 6 -14keV with bandwidth around 1eV (corresponding to about 1mJ/eV spectral density) were generated. Combined burst-mode, multi-MHz repetition accelerator, HXRSS...
Room-temperature 1.54 μm electroluminescence (EL) was compared for Au/SiO2:Er/n+-Si and Au/SiOx:Si:Er/n+-Si diodes under reverse bias. The 18 nm thick SiO2:Er SiOx:Si:Er films were deposited by the magnetron sputtering technique. maximum of EL intensity reached after annealing at 900 °C (SiO2:Er) 800 (SiOx:Si:Er). threshold potential about 4 6 V diodes, respectively. power efficiency larger diode than that six times. Our experimental results demonstrate existence Si nanoclusters reduces...
The proposed high repetition-rate electron beam from the LCLS-II and High Energy (LCLS-II-HE) upgrade are promising sources as drivers for an X-ray FEL Oscillator (XFELO) operating at both harmonic fundamental frequencies. In this contribution we present start-to-end simulations XFELO fifth with 4 GeV 8 LCLS-II-HE beam. longitudinal phase space is optimized by shaping photoinjector laser adjusting various machine parameters. show that high-flux output radiation pulses 10¹⁰ photons 3 meV...
Time-resolved diagnostics at Free-Electron Laser (FEL) facilities, in particular electron beam longitudinal phase space (LPS) and FEL power profile measurements, provide information highly valuable for users, machine development studies, setup. We investigate the slice energy resolution of passive streaker setups, effect an chirp on measured spread. Downstream hard X-ray SASE2 beamline European XFEL, these measurements are enabled by a single-plate non-movable wakefield streaker, essentially...