A5053299225- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Advanced X-ray Imaging Techniques
- Superconducting Materials and Applications
- Gyrotron and Vacuum Electronics Research
- Photocathodes and Microchannel Plates
- Electron and X-Ray Spectroscopy Techniques
- Laser-Plasma Interactions and Diagnostics
- Advanced Electron Microscopy Techniques and Applications
- Laser Design and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Crystallography and Radiation Phenomena
- Magnetic confinement fusion research
- Particle Detector Development and Performance
- Advancements in Photolithography Techniques
- Laser-Matter Interactions and Applications
- Distributed and Parallel Computing Systems
- Spectroscopy and Laser Applications
- Photonic and Optical Devices
- Plasma Diagnostics and Applications
- Atomic and Subatomic Physics Research
- Pulsed Power Technology Applications
- Advanced Data Storage Technologies
- Advanced Surface Polishing Techniques
- Integrated Circuits and Semiconductor Failure Analysis
Brookhaven National Laboratory
2016-2025
National Synchrotron Light Source II
2003-2025
Brookhaven College
2019
Stanford Synchrotron Radiation Lightsource
2006-2017
RIKEN BNL Research Center
2002-2011
Budker Institute of Nuclear Physics
1993-2001
Siberian Branch of the Russian Academy of Sciences
2001
We report the first experimental results on a high-gain harmonic-generation (HGHG) free-electron laser (FEL) operating in ultraviolet. An 800 nm seed from Ti:sapphire has been used to produce saturated amplified radiation at 266 third harmonic. The confirm predictions for HGHG FEL operation: stable central wavelength, narrow bandwidth, and small pulse-energy fluctuation.
Driven by life-science applications, a mega-electron-volt Scanning Transmission Electron Microscope (MeV-STEM) has been proposed here to image thick frozen biological samples as conventional (TEM) may not be suitable thicker than 300–500 nm and various volume electron microscopy (EM) techniques either suffering from low resolution, or speed. The high penetration of inelastic scattering signals MeV electrons could make the MeV-STEM an appropriate microscope for 10 μm more with nanoscale...
We investigate properties of optical elements in the cavity an x-ray laser oscillator with emphasis on power loss a monochromatic Gaussian radiation beam upon passing through them using analytical and numerical approaches. Here we assume comprises refractive lenses Bragg crystals exploiting symmetric scattering. For lens, include focusing curvature effects while angular filtering due to finite Darwin width crystal. Our results indicate feasibility out-coupling range 0.5%–28% intracavity...
High-resolution imaging using Transmission Electron Microscopy (TEM) is essential for applications such as grain boundary analysis, microchip defect characterization, and biological imaging. However, TEM images are often compromised by electron energy spread other factors. In mode, where the objective projector lenses positioned downstream of sample, electron–sample interactions cause loss, which adversely impacts image quality resolution. This study introduces a simulation tool to estimate...
A measurable chaos indicator is used as the online optimization objective in tuning a complicated nonlinear system—the National Synchrotron Light Source-II storage ring. Through analyzing Shannon entropy measured Poincaré maps, not only can commonly characterizations be extracted, but more importantly, quantified and then for an regularization of these maps. The method itself general applicable to other tunable systems well. Published by American Physical Society 2025
The external seed of the high-gain harmonic generation (HGHG) free-electron laser (FEL) determines wavelength output radiation. Therefore, tunability such a depends upon seed. In this paper, we present and discuss an alternative scheme for tunable HGHG FEL wherein seed's is fixed variations in radiation are achieved by tuning accelerator. As illustration, apply our proposed to deep ultraviolet free electron (DUV FEL) at Brookhaven National Laboratory demonstrating ability attain about +/-10%...
We report on an experimental investigation characterizing the output of a high-gain harmonic-generation (HGHG) free-electron laser (FEL) at saturation. A seed CO2 wavelength 10.6 microm was used to generate amplified FEL 5.3 microm. Measurement frequency spectrum, pulse duration, and correlation length verified that light is longitudinally coherent. Investigation electron energy distribution harmonic energies provides evidence for saturated HGHG operation.
To optimize electron energy for in situ imaging of large biological samples up to 10 μm thickness with nanoscale resolutions, we implemented an analytical model based on elastic and inelastic characteristic angles. This has been benchmarked by Monte Carlo simulations can be used predict the transverse beam size broadening as a function while probe traverses through sample. As result, optimal choice realized. In addition, impact dose-limited resolution was analysed. While sample is less than...
Inverse Compton Scattering (ICS) is an emerging compact X-ray source technology, where the small size and high spectral brightness are of interest for multitude applications. However, to satisfy practical flux requirements, a high-repetition-rate ICS system needs be developed. To this end, paper reports experimental demonstration peak operating in burst mode at 40 MHz. A pulse train interaction has been achieved by recirculating picosecond CO2 laser inside active optical cavity synchronized...
We present the experimental investigation of a collective effect driving strong modulation in longitudinal phase space high-brightness electron beam. The measured beam energy spectrum was analyzed order to reveal main parameters modulation. results were compared with model space-charge oscillations space. measurements and analysis allowed us determine range observed on dynamics illustrate its potential impact short-wavelength free-electron laser performance.
In this paper, we explore a method to manipulate low energy electron bunches in space charge dominated regime, and use design linac bunch compressors compress regime. the method, effects instead of avoiding them; i.e., forces generate required chirp ordinary which uses rf accelerating system chirp. We redefine concepts dispersion function beta functions regime guide optimization. Using study (5--22 MeV) compressor produce short ($\ensuremath{\sim}150\text{ }\mathrm{fs}$) small size...
Measurements of the thermal emittance an electron beam produced by photoemission from copper cathode a high power RF cavity are presented. The RMS normalized has been measured as function laser spot size, applied surface field, and polarization at normal incidence. Local field enhancement due to effects is found increase substantially beyond that expected for perfect planar surface.
We investigate properties of optical elements in the cavity an X-ray free electron laser oscillator with emphasis on power loss a monochromatic Gaussian radiation beam upon passing through them using analytical and numerical approaches. Here we assume comprises refractive lenses Bragg crystals exploiting symmetric scattering. For lens, include focusing curvature effects while angular filtering due to finite Darwin width crystals. Our results indicate feasibility outcoupling range 0.5-28 %...
To align with the global trend of integrating synchrotron light source (SLS) and free electron laser (FEL) facilities on one site, in line examples such as SPring-8 SACLA Japan ELETTRA FERMI Italy, we actively explore FEL options leveraging ultralow-emittance beam NSLS-II upgrade. These show promising potential for synergy storage ring (SR) operations, thereby significantly enhancing our facility’s capabilities. Echo-enabled harmonic generation (EEHG) is well-suited to SR-based FELs, has...
We present a detailed derivation of formula for the small-gain calculation an x-ray free electron laser oscillator (XFELO) based on medium-energy (3–4 GeV) storage ring. found harmonic lasing and strong focusing are essential this beam energy range. Taking small-signal low-gain developed by Kim his colleagues, we modified it in such way that gain can be calculated without “no approximation,” applied, as well lasing. In formula, is represented product two factors with one them depending only...
The resolution of a mega-electron-volt scanning transmission electron microscope (MeV-STEM) is primarily governed by the properties incident beam and angular broadening effects that occur within thick biological samples microchips. A precise understanding mitigation these constraints require detailed knowledge emittance, aberrations in STEM column optics, energy-dependent elastic inelastic critical angles materials being examined. This simulation study proposes standardized experimental...
Having previously reported that separating the two stages of echo-enabled harmonic generation (EEHG) with one or more bending magnet (BM) sections allows BMs to serve as desired source momentum compaction, here we demonstrate this arrangement can greatly reduce total energy modulation required by any 4th synchrotron light source, leading higher repetition rates well stronger coherent radiation output power, significant benefits. Since EEHG beamline performance is mainly determined beam...
Several proposals have been put forward for converting electron accelerators to inverse Compton scattering (ICS) gamma sources. Typical approaches suggest combining near-IR solid-state lasers operating continuously at a multimegahertz repetition rate with e-beams when setting their interaction point inside field-enhancement, Fabry-Perot optical cavity. We introduce here an alternative method of pairing particle accelerator beams trains long-wave-infrared,...
A preliminary design of a mega-electron-volt (MeV) monochromator with 10-5 energy spread for ultrafast electron diffraction (UED) and microscopy (UEM) is presented. Such narrow advantageous in both the single shot mode, where momentum resolution improved, accumulation shot-to-shot jitter reduced. In single-shot we numerically optimized efficiency up to 13% achieving 1.3 million electrons per pulse. mitigate degradation caused by jitter, an gun phase yields only mild reduction efficiency,...
Prebunching via echo-enabled harmonic generation (EEHG) is an efficient way to reduce the radiator length and improve longitudinal coherence as well output stability in storage-ring-based free-electron lasers. We propose a conceptual design, which uses two straight sections seed coherent extreme-ultraviolet (EUV) soft X-ray emission with nearly MHz repetition rate. To take large energy spread (10-3) of storage ring into account utilize existing bending magnets between first chicane, we...