A5052336272- Particle Accelerators and Free-Electron Lasers
- Advanced X-ray Imaging Techniques
- Particle accelerators and beam dynamics
- Gyrotron and Vacuum Electronics Research
- Laser-Plasma Interactions and Diagnostics
- Advanced Electron Microscopy Techniques and Applications
- Superconducting Materials and Applications
- Laser Design and Applications
- Crystallography and Radiation Phenomena
- Laser-Matter Interactions and Applications
- Photocathodes and Microchannel Plates
- X-ray Spectroscopy and Fluorescence Analysis
- Particle Detector Development and Performance
- Electromagnetic Simulation and Numerical Methods
- Advancements in Photolithography Techniques
- Adrenal and Paraganglionic Tumors
- Scientific Computing and Data Management
- Adaptive optics and wavefront sensing
- Photonic and Optical Devices
- Atomic and Subatomic Physics Research
- Distributed and Parallel Computing Systems
- Electron and X-Ray Spectroscopy Techniques
- Experimental Learning in Engineering
- Diamond and Carbon-based Materials Research
- Terahertz technology and applications
SLAC National Accelerator Laboratory
2016-2025
Dalhousie University
2024
Menlo School
2007-2023
Stanford University
2008-2023
RIKEN
2020
University of Science and Technology of China
1994-2019
Shanghai Institute of Applied Physics
2019
Pohang Accelerator Laboratory
2019
Huazhong University of Science and Technology
2019
Shanghai Advanced Research Institute
2019
Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time length scales. SLAC National Accelerator Laboratory recently launched Electron Diffraction (UED) microscopy Initiative aiming at developing next generation ultrafast scattering instruments. As first...
The Linac Coherent Light Source (LCLS) is an x-ray free-electron laser project presently in a commissioning phase at the SLAC National Accelerator Laboratory. We report here on very low-emittance measurements made low bunch charge, and few femtosecond length produced by LCLS compressors. Start-to-end simulations associated with these beam parameters show possibilities of generating hundreds GW 1.5 \AA{} wavelength nearly single longitudinally coherent spike nm 2-fs duration.
The Linac Coherent Light Source is a SASE x-ray free-electron laser (FEL) project presently under construction at SLAC [J. Arthur et al., SLAC-R-593, 2002.]. injector section, from drive and rf photocathode gun through first bunch compressor chicane, was installed in the fall of 2006. initial system commissioning with an electron beam completed August 2007, goal 1.2-micron emittance 1-nC demonstrated. second phase commissioning, including full linac, planned for 2008, FEL 2009. We report...
A microbunching instability driven by longitudinal space charge, coherent synchrotron radiation, and linac wakefields is studied for the light source (LCLS) accelerator system. Since uncorrelated (local) energy spread of electron beams generated from a photocathode rf gun very small, gain may be large enough to significantly amplify rf-gun modulations or even shot-noise fluctuations beam. The can increased an order magnitude provide strong Landau damping against without degrading...
The Linac Coherent Light Source has added a self-seeding capability to the soft x-ray range using grating monochromator system. We report demonstration of with measured resolving power 2000--5000, wavelength stability ${10}^{\ensuremath{-}4}$, and an increase in peak brightness by factor 2--5 across photon energy 500--1000 eV. By avoiding need for at experimental station, self-seeded beam can deliver as much 50-fold higher users.
The very bright electron beam required for an x-ray free-electron laser (FEL), such as the linac coherent light source (LCLS), is susceptible to a microbunching instability in magnetic bunch compressors, prior FEL undulator. uncorrelated energy spread LCLS can be increased by order of magnitude provide strong Landau damping against without degrading performance. To this end, ``laser-heater'' system has been installed injector, which modulates 135-MeV with IR-laser short undulator, enclosed...
We report the first measurements of x-ray single-pulse duration and two-pulse separation at Linac Coherent Light Source using a cross-correlation technique involving x rays electrons. An emittance-spoiling foil is adopted as very simple effective method to control output pulse. A minimum pulse about 3 fs full width half maximum has been measured together with controllable (delay) between two pulses. This provides critical temporal diagnostics for experiments such pump-probe studies.
A novel approach to generating coherent x rays with 10(9)-10(10) photons and femtoseconds duration per laser pulse is proposed. This high intensity x-ray source realized first by the front tilt of a lateral fed extend electron-laser synchronic interaction time several orders, which accomplishes high-gain free-electron-laser-type exponential growth process emission highly microbunched electron beam. Second, two methods are presented enhance effective optical undulator strength parameter. One...
Energy extraction efficiency of a free electron laser (FEL) can be greatly increased using tapered undulator and self-seeding. However, the rate is limited by various effects that eventually lead to saturation peak intensity power. To better understand these effects, we develop model extending Kroll-Morton-Rosenbluth, one-dimensional theory include physics diffraction, optical guiding, radially resolved particle trapping. The predictions agree well with GENESIS single-frequency numerical...
We show that the spectral properties of a self-amplified spontaneous emission x-ray free-electron laser can be controlled by modulating gain in magnetic undulators, thus producing one or several lines within single few femtosecond pulse. By varying field along undulator and electron beam transport line, system we demonstrate tailor spectrum to optimally meet numerous experimental requirements for multicolor operation.
We report the generation of ultrahigh brightness X-ray pulses using Fresh Bunch Self-Seeding (FBSS) method in an Free Electron Laser (XFEL). The FBSS uses two different electron slices or bunches, one to generate seed and other amplify it after monochromator. This circumvents trade-off between power slice energy spread, which limits efficiency regular self-seeded FELs. experiment, performance is limited by existing hardware, shows feasibility, generating 5.5 keV photon are 9 fs long 7.3...
The linac coherent light source (LCLS) is a self-amplified spontaneous emission (SASE) free-electron laser (FEL) operating at fundamental photon energies from 0.5 to 10 keV. Characterization of the higher harmonics present in FEL beam important users, for whom harder x rays can either extend useful wavelength range or increase experimental backgrounds. We measurements power both second and third harmonics, compare results expectations simulations. also studies transport harmonic as function...
We present a novel method for measuring the duration of femtosecond x-ray pulses from self-amplified spontaneous emission free electron lasers by performing statistical analysis in spectral domain. Analytical expressions correlation function were derived linear regime to extract both pulse and spectrometer resolution. Numerical simulations confirmed that can be also used nonlinear regime. The was demonstrated experimentally at Linac Coherent Light Source durations down 13 fs FWHM.
In this paper we present undulator magnet tapering methods for obtaining high efficiency and multiterawatt peak powers in x-ray free electron lasers (XFELs), a key requirement enabling 3D atomic resolution single molecule imaging nonlinear science. The power of tapered XFELs is sensitive to time dependent effects, like synchrotron sideband growth. To analyze dependence detail perform comparative numerical optimization the magnetic field profile including intentionally disabling these...
In order to reach the high peak current required for an x-ray free electron laser, two separate magnetic dipole chicanes are used in Linac Coherent Light Source accelerator compress bunch length stages. these compressors, coherent synchrotron radiation (CSR) can be emitted either by a short or any longitudinal density modulation that may on bunch. this paper, we report detailed measurements of CSR-induced energy loss and transverse emittance growth compressors. Good agreement is found...
This Letter reports the first observations of an anomalous hollow electron beam in Duke storage ring. Created by exciting single-bunch a lattice with negative chromaticity, consists solid core inside and large ring outside. We report detailed measurements phenomenon, including its distinct image pattern, spectrum signature, evolution time. By capturing postinstability bursting beam, is unique model system for studying transverse instabilities, particular, interplay wakefield nonlinearity. In...
Abstract C 3 is an opportunity to realize e + - collider for the study of Higgs boson at √ s = 250 GeV, with a well defined upgrade path 550 GeV while staying on same short facility footprint [2,3]. based fundamentally new approach normal conducting linear accelerators that achieves both high gradient and efficiency relatively low cost. Given advanced state designs, key system requires technical maturation main linac. This paper presents staged towards demonstrate technology Direct (source...