A5073240104- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Advanced X-ray Imaging Techniques
- Advanced Electron Microscopy Techniques and Applications
- Gyrotron and Vacuum Electronics Research
- Electron and X-Ray Spectroscopy Techniques
- Terahertz technology and applications
- Superconducting Materials and Applications
- Laser-Matter Interactions and Applications
- Laser-Plasma Interactions and Diagnostics
- Photonic and Optical Devices
- Magnetic confinement fusion research
- Crystallography and Radiation Phenomena
- X-ray Spectroscopy and Fluorescence Analysis
- Parallel Computing and Optimization Techniques
- Integrated Circuits and Semiconductor Failure Analysis
- Atomic and Subatomic Physics Research
- Laser Design and Applications
- Laser-induced spectroscopy and plasma
- X-ray Diffraction in Crystallography
- Digital Holography and Microscopy
- Crystallization and Solubility Studies
- Photocathodes and Microchannel Plates
- Analytical chemistry methods development
- Advanced Data Compression Techniques
Brookhaven National Laboratory
2016-2025
National Synchrotron Light Source II
2017-2025
Boston University
2024
China National Petroleum Corporation (China)
2024
Duke University
2021-2024
SLAC National Accelerator Laboratory
2023
Henan University
2019
Lyncean Technologies (United States)
2018
Stanford Synchrotron Radiation Lightsource
2017
Donghua University
2015
Cryo-electron microscopy (cryo-EM) is a powerful tool for imaging biological samples but typically limited by sample thickness, which restricted to few hundred nanometers depending on the electron energy. However, there growing need techniques capable of studying up 10 µm in thickness while maintaining nanoscale resolution. This motivates use mega-electron-volt scanning transmission (MeV-STEM), leverages high penetration power MeV electrons generate high-resolution images thicker samples. In...
We report the generation of tunable, narrow-band, few-cycle and multicycle coherent terahertz (THz) pulses from a temporally modulated relativistic electron beam. demonstrate that frequency THz radiation number oscillation cycles electric field can be tuned by changing modulation period beam through shaped photocathode drive laser. The central spectrum is tunable $\ensuremath{\sim}0.26$ to 2.6 with bandwidth $\ensuremath{\sim}0.16\text{ }\text{ }\mathrm{THz}$.
A variety of volume electron microscopy techniques have been developed to visualize thick biological samples. However, the resolution is limited by sliced section thickness (>30–60 nm). To preserve samples in a hydrated state, cryo-focused ion beam scanning has developed, providing nm resolutions. this method time-consuming, requiring 15–20 h image 10 μm sample with an 8 slice thickness. There pressing need for that allows rapid and efficient study while maintaining nanoscale resolution....
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...
Objectives We aimed to clarify the influence of facial expressions on providing early recognition and diagnosis Parkinson’s disease (PD). Methods included 18 people with PD controls. The participants were asked perform 12 monosyllabic tests, 8 disyllabic 6 multisyllabic tests whole process recorded. Then 26 video clips recorded used decipher muscle movements face expression via Noldus FaceReader 7.0 software. 16 suitable variables selected construct a Bayesian network model. Results area...
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...
This paper investigates the combination of laser-induced breakdown spectroscopy (LIBS) and deep convolutional neural networks (CNNs) to classify copper concentrate samples using pretrained CNN models through transfer learning. Four were compared. The LIBS profiles augmented into 2D matrices. Three learning methods tried. All got a high classification accuracy >92%, with highest at 96.2% for VGG16. These results suggested that knowledge learned from machine vision by can accelerate training...
Two transmission-mode diamond X-ray beam position monitors installed at National Synchrotron Light Source (NSLS) beamline X25 are described. Each monitor is constructed around two horizontally tiled electronic-grade (p.p.b. nitrogen impurity) single-crystal (001) CVD synthetic diamonds. The position, angle and flux of the white can be monitored in real time with a resolution 500 nm horizontal direction 100 vertical for 3 mm × 1 beam. first has been operation more than one year without any...
Laser-induced breakdown spectroscopy system based on high-repetition-rate microchip laser (HR-LIBS) has been widely used in elemental analysis due to its high energy stability, good portability and fast spectral acquisition speed. However, repeated ablation powder pellets like soil coal using HR-LIBS encounters the problem of serious decline measurement accuracy. In this work, relationship between scanning parameters, their correlation with intensity, as well optimization approach were...
Advanced light sources using relativistic electrons rely on coherent emission from high-density (compressed) beams. These beams, typically produced by photoinjected linear accelerators, can suffer uncontrolled microbunching instabilities that are difficult to manage, since a complete understanding of their growth due space charge and other wakefields is lacking. Here we present the first systematic measurements instability electron beams premodulated in controlled fashion. By comparing...
We study the dynamics of an isolated spike radiation in superradiant regime. show that conditions exist where pulse moves with a group velocity larger than light vacuum and is followed by pedestal resulting from complex postsaturation dynamics. The tail constituted train subpulses both transverse longitudinal coherence decaying amplitudes. analyze dynamical leading to formation main tail. correlation structure phase space electrons, provide recipe partially suppress this
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...
Segmentation of brain tissue from MR images provides detailed quantitative analysis for accurate diagnosis, detection, and classification diseases, plays an important role in neuroimaging research clinical environments. Recently, a plethora deep learning-based approaches have been employed to achieve segmentation fetuses, infants, adults with impressive outcomes. However, owing the existence noise, motion artifacts, edge blurriness images, automatically segmenting accurately is still very...
We demonstrate that the intense electric field of a subpicosecond single-cycle terahertz pulse can control and manipulate temporal, spectral, spatial phase copropagating ultrashort laser through Pockels effect in an electro-optic crystal. In temporal spectral domains, THz impart either positive or negative quadratic modulation to probe pulse, leading shift, broadening, expansion compression. While acting domain, THz-induced induces lenslike effect, providing focusing defocusing beam. The...
We demonstrate that an intense single-cycle terahertz (THz) pulse can act as a time lens to phase modulate and compress copropagating ultrashort laser pulse. By using the THz-induced modulation glass plate group velocity dispersive element, we have compressed unchirped $~165$ fs $~45$ fs.
Fully coherent x rays can be generated by self-seeding x-ray free electron lasers (XFELs). Self-seeding a forward Bragg diffraction (FBD) monochromator has been recently proposed [G. Geloni, V. Kocharyan, and E. Saldin, J. Mod. Opt. 58, 1391 (2011)] demonstrated [J. Amann et al., Nat. Photonics 6, 693 (2012)]. Characteristic time ${\mathcal{T}}_{0}$ of FBD determines the power, spectral, characteristics seed [Yu. Shvyd'ko R. Lindberg, Phys. Rev. ST Accel. Beams 15, 100702 Here we show that...
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...