A5019098210- Particle Accelerators and Free-Electron Lasers
- Advanced X-ray Imaging Techniques
- Particle accelerators and beam dynamics
- Electron and X-Ray Spectroscopy Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Laser-Plasma Interactions and Diagnostics
- Advanced Electron Microscopy Techniques and Applications
- Advancements in Photolithography Techniques
- Gyrotron and Vacuum Electronics Research
- Superconducting Materials and Applications
- Laser-Matter Interactions and Applications
- Magnetic properties of thin films
- Crystallography and Radiation Phenomena
- Silicon Carbide Semiconductor Technologies
- Medical Imaging Techniques and Applications
- Advanced Surface Polishing Techniques
- Photocathodes and Microchannel Plates
- Laser Design and Applications
- High-Energy Particle Collisions Research
- Nuclear Physics and Applications
- Magneto-Optical Properties and Applications
- Quantum Chromodynamics and Particle Interactions
- HVDC Systems and Fault Protection
- Semiconductor materials and devices
- Electrical Fault Detection and Protection
Barts Health NHS Trust
2025
Texas Instruments (United States)
2025
Old Dominion University
2016-2023
Met Office
2023
Brookhaven National Laboratory
2000-2022
University of Arkansas at Fayetteville
2008-2012
RIKEN BNL Research Center
1999-2007
National Synchrotron Light Source II
1987-2003
Stanford Synchrotron Radiation Lightsource
1991
Cornell University
1984-1985
A high-gain harmonic-generation free-electron laser is demonstrated. Our approach uses a laser-seeded to produce amplified, longitudinally coherent, Fourier transform-limited output at harmonic of the seed laser. carbon dioxide wavelength 10.6 micrometers produced saturated, amplified second-harmonic wavelength, 5.3 micrometers. The experiment verifies theoretical foundation for technique and prepares way application this in vacuum ultraviolet region spectrum, with ultimate goal extending...
Specular reflectivity of p-polarized light near the iron ${\mathit{L}}_{\mathrm{II}}$ and ${\mathit{L}}_{\mathrm{III}}$ absorption edges was measured from a single-crystal film with an external magnetic field perpendicular to scattering plane. Large changes in were observed upon reversal direction field. We attribute this resonant magnetization-sensitive effect interference between nonmagnetic contribution scattering. Similar effects can be expected other ferromagnetic ferrimagnetic systems.
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.
Abstract Planar transition aluminas are gaining attention as models for alumina-based catalysts [I] because of their attractiveness study by modern surface analytical techniques [2], electron optical methods [3], and reflection spectroscopy [4–7]. In this context "planar" means a thin (<10–4 cm) flat oxide layer uniform thickness. Conventional high area which used commercially adsorbents, catalysts, catalyst supports usually require grinding /or pressing into disks characterization these...
Dichroic interference effects were observed in circularly polarized soft-x-ray reflectivity at the Co ${\mathit{L}}_{2,3}$ edges of a magnetic multilayer. The data show maximum asymmetry ratio 80%, greater than degree circular polarization incident light, changeover dichroic characteristics with increasing grazing angle, and an inverted pattern angular dependence ratio. These observations are explained successfully by classical electromagnetic model calculation which includes complete state...
The scanning photoelectron microscope at the National Synchrotron Light Source (NSLS) has recently recorded micrographs with a resolution below half micron. To demonstrate elemental and chemical sensitivity submicron level, an artificial structure consisting of Al SiO2 lines on boron-doped silicon substrate was examined. 2p Si primary photoelectrons as well O KVV Auger electrons were used for image formation. Contrast reversal between areas observed in images formed from oxide-shifted...
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.
By making a relativistic electron beam wiggle its way through an array of magnets, one can generate intense coherent light with wavelengths tunable from centimeters to angstroms.
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation H. Ade, J. Kirz, S. Hulbert, E. Johnson, Anderson, D. Kern; Images of a microelectronic device with the X1‐SPEM, first generation scanning photoemission microscope at National Synchrotron Light Source. Vac. Sci. Technol. A 1 May 1991; 9 (3): 1902–1906. https://doi.org/10.1116/1.577541 Download citation file:...
VISA (Visible to Infrared SASE Amplifier) is a high-gain self-amplified spontaneous emission (SASE) free-electron laser (FEL), which achieved saturation at 840 nm within single-pass 4-m undulator. The experiment was performed the Accelerator Test Facility BNL, using high brightness 70-MeV electron beam. A gain length shorter than 18 cm has been obtained, yielding total of 2 x 10(8) saturation. FEL performance, including spectral, angular, and statistical properties radiation, characterized...
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 report the first implementation of an in situ glow discharge cleaning procedure for removal carbon contamination from x-ray optical surfaces. In obviates need time-consuming and costly process element removal, or repolishing, remounting, realignment usually necessary to restore optics their original condition. The apparatus required is quite simple can easily be fitted most existing UHV (ultrahigh vacuum) mirror boxes monochromators. Results with several monochromators at Brookhaven...
We present a new paradigm for computation of radiation spectra in the non-linear regime operation inverse Compton sources characterized by high laser intensities. The resulting simulations show an unprecedented level agreement with experiments. Increasing intensity changes longitudinal velocity electrons during their collision, leading to considerable broadening scattered spectra. effects such ponderomotive are so deleterious that most either remain at low intensities or pay steep price...
Previous work on calculating energy spectra from Compton scattering events has either neglected considering the pulsed structure of incident laser beam, or calculated these effects in an approximate way subject to criticism. In this paper, problem been reconsidered within a linear plane wave model for beam. By performing proper Lorentz transformation Klein-Nishina cross section, spectrum calculation can be created which allows electron beam spread and emittance accurately calculated,...
As Compton x-ray and gamma-ray sources become more prevalent, to understand their performance in a precise way, it becomes important be able compute the distribution of scattered photons precisely. For example, codes have been developed at Old Dominion University which were used Dresden Source detail. An ideal model would (i) include full effect frequency relations between incident photons, (ii) allow field strength large enough that nonlinear effects are captured, (iii) electron beam...
We have been developing an instrument that combines the techniques of x-ray photoelectron spectroscopy and zone plate microfocusing to perform spectromicroscopy. The X1A undulator provides a bright photon source in soft range with high degree spatial coherence (a requirement for focusing). A spherical grating monochromator selects desired energy 280–800 eV range. Fresnel focuses beam small spot. Photoelectron spectra can be acquired from irradiated area electron analyzer. With focused on...
In this work we combine elements of chirped pulse amplification techniques, now familiar in solid-state lasers, with an amplifier based upon a seeded free-electron laser (FEL). The resulting device would produce amplified pulses unprecedented brevity at wavelengths shorter than can be currently obtained by any tunable system. We use subharmonically FEL to illustrate the concept. Radiation from Ti:sapphire is frequency tripled and stretched optically provide coherent seed for FEL. When...
We have developed a new compact water-cooled beam position monitor for use at the NSLS X-13 Insertion Device Development beamline, currently fitted with high-power, high-brightness soft-x-ray undulator. describe novel geometry of and present results tests which explore its sensitivity, stability, linearity. These were obtained on Beamline Research white light U14B, VUV ring suggest that monitors this type might be adapted to other facilities similar spectral characteristics.
Due to increased demand and deployment of new technologies, such as electric vehicles, utilities face increasing fault currents in their systems. As a consequence protection devices must have higher ratings. Replacing existing infrastructure can prove expensive complicated. Fault current limiters promise an upgrade solution that will mitigate the need for replacing breakers keep within ratings equipment. SiC offers several key advantages grid-connected power electronics, smaller footprint,...