A5023393186- Advanced X-ray Imaging Techniques
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- X-ray Spectroscopy and Fluorescence Analysis
- Superconducting Materials and Applications
- Particle physics theoretical and experimental studies
- Radiation Detection and Scintillator Technologies
- Particle accelerators and beam dynamics
- High-pressure geophysics and materials
- Advanced Electron Microscopy Techniques and Applications
- Advanced MRI Techniques and Applications
- Magnetic properties of thin films
- Magnetic confinement fusion research
- Solid State Laser Technologies
- Neutrino Physics Research
- Electromagnetic Launch and Propulsion Technology
- Atomic and Subatomic Physics Research
- Non-Destructive Testing Techniques
- Nuclear Physics and Applications
- Photocathodes and Microchannel Plates
- Crystallography and Radiation Phenomena
- Fossil Insects in Amber
- Medical Imaging Techniques and Applications
- Enzyme Structure and Function
- Laser-Matter Interactions and Applications
Lawrence Berkeley National Laboratory
2007-2018
SLAC National Accelerator Laboratory
2015
Planetary Science Institute
2008
University of California, Berkeley
2008
Argonne National Laboratory
1992-1996
Moscow Engineering Physics Institute
1994
Massachusetts Institute of Technology
1994
We present the development and characterization of a dedicated resonant soft x-ray scattering facility. Capable operation over wide energy range, beamline endstation are primarily used for from matter systems around carbon K-edge (∼285 eV). describe specialized design instrument characteristics beamline. Operational immediate interest to users such as polarization control, degree higher harmonic spectral contamination, detector noise delineated. Of special is rejection system that improves...
The X-ray micro-Tomography Facility at the Advanced Light Source has been in operation since 2004. source is a superconducting bend magnet of critical energy 11.5 keV; photon coverage 8-45 KeV monochromatic mode, and filtered white light option yields useful photons up to 50 keV. A user-friendly graphical user interface allows users collect tomographic radiographic data sets with options including tiled time series sets. We will focus on recent projects that utilize sample environments for...
A compact ultrahigh temperature tensile testing instrument has been designed and fabricated for in situ x-ray micro-tomography using synchrotron radiation at the Advanced Light Source, Lawrence Berkeley National Laboratory. It allows real time micro-tomographic imaging of test materials under mechanical load temperatures up to 2300 °C controlled environments (vacuum or gas flow). Sample heating is by six infrared halogen lamps with ellipsoidal reflectors arranged a confocal configuration,...
Nano-roughness limits the emittance of electron beams that can be generated by high efficiency photocathodes, such as thermally reacted alkali antimonide thin films. However there is an urgent need for photocathodes produce order magnitude or more lower than present day systems in to increase transverse coherence width beam. In this paper we demonstrate a method producing cathodes with near atomic smoothness reproducibility.
Measurements of the intrinsic emittance and transverse momentum distributions obtained from a metal (antimony thin film) photocathode near below photoemission threshold are presented. show that is limited by lattice temperature cathode as incident photon energy approaches threshold. A theoretical model to calculate this An excellent match between experimental measurements calculations demonstrated. These relevant low electron sources for Free Electron Lasers Ultrafast Diffraction experiments.
With a membrane based mechanism to allow for pressure change in sample radial diffraction diamond anvil cell and simultaneous infrared laser heating, it is now possible investigate texture changes during deformation phase transformations over wide range of temperature-pressure conditions. The device used study bcc (α), fcc (γ), hcp (ε) iron. In iron, room temperature compression generates characterized by (100) (111) poles parallel the direction. During induced transformation subset...
An x-ray streak camera with high resolution in both temporal and spatial dimensions has been developed. It is achieved by using extraction-mesh acceleration a large opening aperture magnetic solenoid lens design. High resolutions the can be retained wide 53ps time window. A of 233fs 10μm have demonstrated Au photocathode.
The role of orbital magnetism in the laser-induced demagnetization Fe∕Gd multilayers was investigated using time-resolved x-ray magnetic circular dichroism at 2ps time resolution given by an streak camera. An ultrafast transfer angular momentum from spin via to lattice observed which characterized rapidly thermalizing and momenta. Strong interlayer exchange coupling between Fe Gd led a simultaneous both layers.
K-Cs-Sb bialkali antimonide photocathodes grown by a triple-element codeposition method have been found to excellent quantum efficiency (QE) and outstanding near-atomic surface smoothness employed in the VHF gun Advanced Photoinjector Experiment (APEX), however, their robustness terms of lifetime at elevated photocathode temperature has not yet investigated. In this paper, relationship between The origin significant QE degradation temperatures over $70\text{...
The transverse momentum of electrons produced by a photocathode contributes significantly to the performance several different types accelerator-based light sources, such as Free Electron Lasers, well systems designed for ultrafast electron diffraction and dynamic transmission microscopy. Minimization emittance from photocathodes is subject intensive research, therefore measurement this parameter great importance. Here, we describe simple system that offers real time measurements can be...
Most advanced applications of polymers rely on heterogeneous structures or specific interfacial properties to yield desired performance and functionalities. Rational design application require that these be characterized. Recently, it has been demonstrated soft x-ray scattering is a unique complementary technique conventional hard neutron an excellent tool for polymer structure determination with improved chemical sensitivity. Efforts enhance the capabilities efficiency through use CCD...
Laser driven plasma light sources offer highly intense output in the UV-visible region combined with a source size as small 100 μm. In order to effectively use high brightness applications, stigmatic monochromator and focusing system must be used. Here we describe simple preserving optical that should useful across broad range of applications. The flux this is between 6 × 10(11) ph∕s 4 10(12) spectra resolution 1.7 nm field spot 0.1 mm from UV VIS range.
An ultrafast x-ray streak camera is under development at LBNL for application primarily to studies of magnetization dynamics. In initial work, a temporal resolution 900fs in accumulative mode 5 KHz has been achieved. These results and methods currently being developed improve the repetition rate are resented. One primary limits caused by finite energy width electron distribution from photocathode. The positive time flight dispersion with accelerating region can be countered introduction...
A titanium-doped sapphire regenerative dual-amplifier array operating at multi-kHz repetition rates has been developed for synchrotron radiation ultra-fast x-ray applications. The thermal lensing of the crystal in amplifiers is virtually eliminated by cryogenic cooling laser crystal. output energy measured to be greater than 2.6 mJ and pulse length was compressed less 70 fs. mode a near perfect Gaussian TEM00 with an M(2) factor 1.02. performance amplifier system excellent agreement...
After the formidable results of X-ray 4th generation light sources based on free electron lasers around world, a new revolutionary step is undergoing to extend FEL performance from present few hundred Hz MHz-class repetition rates. In such facilities, temporally equi-spaced pulses will allow for wide range previously non-accessible experiments. The Advanced Photo-injector EXperiment (APEX) at Lawrence Berkeley National Laboratory (LBNL), devoted test capability novel scheme source, VHF-Gun,...
Science needs are pushing the development of MHz-class repetition-rate linac-based facilities generating high-brightness electron beams. The successful lower RF gun schemes cannot be scaled up to MHz rates. At LBNL, we developed VHF-Gun, a room-temperature designed for CW operation and beam performance.
Our experiments at beamline 5.3.1 of the Advanced Light Source feature a 45-cm long x-ray deformable mirror (XDM). We describe experiment and present recent results in two areas. First, we directly image 3 keV beam demonstrate customized shaping its intensity near field. Detailed physics simulations agree very well with actual measurements. Second, use grating interferometer to measure known figure errors applied surface XDM. A relative height change on XDM 2.5 nm RMS is measured an SNR...
The spin dynamics of ferromagnetic thin films following an excitation by ultrashort 100-fs near-infrared laser pulses has recently received much attention. Here, a new approach is described using x-ray magnetic circular dichroism to investigate demagnetization and magnetization switching processes. In contrast magneto-optical measurements, the advantage determining separately orbital components moment. relatively low time resolution synchrotron probe (80 ps FWHM) overcome employing ultrafast...
The Vanadium/Lithium system has been the recent focus of ANL's Blanket Technology Program, and for last several years, Liquid Metal activities have carried out in direct support ITER (International Thermonuclear Experimental Reactor) breeding blanket task area. A key feasibility issue is development insulator coatings. Design calculations, Hua Gohar,1 show that an electrically insulating layer necessary to maintain acceptably low magnetohydrodynamic (MHD) pressure drop current design....
One of the greatest challenges facing crystallographers has always been how to collect good data. This become especially challenging as chemists are creating more complex compounds and looking extract new exotic structural information from crystals which getting smaller smaller. Often, these produce little or no diffraction on a laboratory diffractometer with long exposures. The past two decades have provided world-class synchrotron facilities help solve problems through combination high...