A5020090520- Advanced X-ray Imaging Techniques
- Advanced Measurement and Metrology Techniques
- Particle Accelerators and Free-Electron Lasers
- Optical measurement and interference techniques
- Surface Roughness and Optical Measurements
- X-ray Spectroscopy and Fluorescence Analysis
- Advancements in Photolithography Techniques
- Optical Coatings and Gratings
- Electron and X-Ray Spectroscopy Techniques
- Spectroscopy Techniques in Biomedical and Chemical Research
- Gyrotron and Vacuum Electronics Research
- Calibration and Measurement Techniques
- Advanced Electron Microscopy Techniques and Applications
- Advanced Surface Polishing Techniques
- Scientific Measurement and Uncertainty Evaluation
- Advanced X-ray and CT Imaging
- Particle accelerators and beam dynamics
- Photonic and Optical Devices
- Adaptive optics and wavefront sensing
- Advanced optical system design
- Optical Systems and Laser Technology
- Cultural Heritage Materials Analysis
- Laser-Plasma Interactions and Diagnostics
- Spectroscopy and Laser Applications
- Terahertz technology and applications
Lawrence Berkeley National Laboratory
2009-2021
Uppsala University
2021
Diablo Valley College
2015-2016
University of California, Berkeley
1992-2008
Utah State University
2002
Montana State University
2002
Oak Ridge National Laboratory
1999
University of California, Davis
1996
Pennsylvania State University
1996
Fusion Academy
1990-1992
Synchrotron radiation based Fourier transform IR (SR-FTIR) spectromicroscopy allows the study of individual living cells with a high signal to noise ratio. Here we report use SR-FTIR technique investigate changes in spectral features from human lung fibroblast (IMR-90) vitro at different points their cell cycle. Clear are observed regions corresponding proteins, DNA, and RNA as G1-phase S-phase finally into mitosis. These include markers for changing secondary structure proteins cell, well...
Bursts of coherent synchrotron radiation at far-infrared and millimeter wavelengths have been observed several storage rings. A microbunching instability has proposed as the source for bursts. However, mechanism yet to be elucidated. We provide first evidence that bursts are due a driven by emission in bunch. Observations made Advanced Light Source consistent with values predicted model. These results demonstrate new regime high energy sources could impact design future sources.
The performance of ALS beamline 7.0 is described. This an integrated system for delivering radiation from a 5 cm period undulator to spectroscopy and microscopy experiments across the range photon energies 60 1200 eV. engineered deliver highest possible flux, with negligible deformation optic surfaces due heating. Two experiment stations are served rapid interchangeability. measured operational parameters, resolution flux delivered, refocus light into small spot at all discussed.
Optical absorption studies were performed to investigate the dependence of fundamental band gap AlxGa1−xN epitaxial films on Al content and applied hydrostatic pressure. The results measurements at atmospheric pressure yielded variation band-gap energy E(x)=3.43+1.44x+1.33x2 eV for system. edge associated with direct Γ shifts linearly towards higher under By examining in samples different AlN mole fractions taking into account difference compressibility between sapphire substrate,...
The role of humic acid (HA) in the biodegradation toxic polycyclic aromatic hydrocarbons (PAHs) has been subject controversy, particularly unsaturated environments. By utilizing an infrared spectromicroscope and a very bright, nondestructive synchrotron photon source, we monitored situ and, over time, influence HA on progression degradation pyrene (a model PAH) by bacterial colony magnetite surface. Our results indicate that dramatically shortens onset time for PAH from 168 to 2 h. In...
We present a variable line-space grating spectrometer for soft x-rays that covers the photon energy range between 130 and 650 eV. The optical design is based on Hettrick–Underwood principle tailored to synchrotron-based studies of radiation-sensitive biological samples. able record entire spectral in one shot, i.e., without any mechanical motion, at resolving power 1200 or better. Despite its slitless design, such can be achieved source spot as large (30×3000) μm2, which important keeping...
At the Advanced Light Source, three protein crystallography beamlines have been built that use as a source one of 6 T single-pole superconducting bending magnets (superbends) were recently installed in ring. The such bend enables development hard X-ray program on relatively low-energy 1.9 GeV ring without taking up insertion-device straight sections. is low power but, owing to small electron beam emittance, it has high brightness. optics are required preserve brightness and match...
The <i>Journal of Biomedical Optics</i> (JBO) is a Gold Open Access journal that publishes peer-reviewed papers on the use novel optical systems and techniques for improved health care biomedical research.
The advent of fully coherent free-electron laser and diffraction-limited synchrotron radiation storage ring sources x-rays is catalyzing the development new ultrahigh accuracy metrology methods. To exploit these sources, needs to be capable determining figure an optical element with subnanometer height accuracy. major limiting factors current absolute ex situ are drift errors due temporal instabilities lab’s environmental conditions systematic inherent instruments. Here, we discuss in detail...
Synchrotron radiation‐based Fourier transform infrared (SR‐FTIR) spectromicroscopy is a newly emerging bioanalytical and imaging tool. This unique technique provides mid‒infrared (IR) spectra, hence chemical information, with high signal‐to‐noise at spatial resolutions as fine 3 to 10 microns. Thus it enables researchers locate, identify, track specific events within an individual living mammalian cell. Mid‐IR photons are too low in energy (0.05−0.5 eV) either break bonds or cause...
The next generation of synchrotrons and free electron laser facilities requires x-ray optical systems with extremely high performance, generally diffraction limited quality. Fabrication use such optics adequate, highly accurate metrology dedicated instrumentation. Previously, we suggested ways to improve the performance Long Trace Profiler (LTP), a slope measuring instrument widely used characterize at long spatial wavelengths. main way is CCD detector corresponding technique for calibration...
We suggest and describe the use of a binary pseudorandom (BPR) grating as standard test surface for measurement modulation transfer function (MTF) interferometric microscopes. Knowledge MTF microscope is absolutely necessary to convert measured height distribution undergoing metrology into an accurate power spectral density (PSD) distribution. For ideal with independent spatial frequency out Nyquist detector array zero response at higher frequencies, BPR would produce flat 1-D PSD spectrum,...
The long trace profiler (Takacs et al.) has found significant applications in measuring the surfaces of synchrotron optics. However, requirements small slope errors at all spatial wavelengths optics mandate more accurate measurements. A straightness reference for greatly increases accuracy instrument. Methods using by interpreting sequential interference patterns are discussed and results measurements presented.
The development of third generation light sources like the Advanced Light Source (ALS) or BESSY II brought to a focus need for high performance synchrotron optics with unprecedented tolerances slope error and micro roughness. Proposed beam lines at Free Electron Lasers (FEL) require optical elements up length one meter, characterized by residual in range 0.1 μrad (rms), rms values nm These must be inspected highly accurate measuring instruments, providing measurement uncertainty lower than...
The X-Ray Optics Laboratory (XROL) at the Advanced Light Source (ALS), a unique optical metrology lab, has been recently moved to new, dedicated clean-room facility that provides improved environmental and instrumental conditions vitally required for high accuracy with state-of-the-art X-ray optics. Besides ALS, XROL serves several DOE labs lack on-site capabilities, including Linac Coherent (LCLS) SLAC LBNL's Center (CXRO). major role of is proactively support development optimal beamline...
The use of synchrotron sources for infrared (IR) spectromicroscopy provides greatly increased brightness that enables high-quality IR measurements at diffraction-limited spatial resolutions. This capability permits synchrotron-based to be applied biological applications resolutions on the order size a single mammalian cell. question then arises, “Does intense beam harm samples?” Mid-IR photons are too low in energy break bonds directly; however, they could cause damage molecules due heating....
Synchrotron radiation (SR)-based Fourier transform infrared (FTIR) spectromicroscopy measurements are presented of HepG2 cells exposed to an environmental contaminant that is a known ligand for the aryl hydrocarbon (Ah) receptor. Measurements were made on treated with Ah receptor-binding model compound 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Compared untreated control cells, displayed unique spectral changes TCDD concentrations 0.01−10.0 nM. Key involved PO, C−O, and C−H stretching...
The performance of a 55-meter Spherical Grating Monochromator (SGM) is described. A resolution 60 meV has been achieved at 400eV, inferred from the linewidths nitrogen 1s-π* resonance. photon flux 4 × 1010 photons/s observed 440eV (and with 0.5 eV resolution). An initial experiment studied core-shell resonances gas-phase ethylene, C2H4. Vibrational fine structure was resolved both for carbon and 1s-Rydberg excitations. Comparison vibrational frequencies ground state ethylene implies that ν1...
A general method is described for the design of single concave grating optical systems. Proper parameter and variable sets are defined, a straightforward technique leads to final set optimized values which minimize merit function based on spectroscopic performance.