A5039488752- Advanced X-ray Imaging Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Electron Microscopy Techniques and Applications
- Crystallography and Radiation Phenomena
- Advanced X-ray and CT Imaging
- Medical Imaging Techniques and Applications
- Astro and Planetary Science
- Electron and X-Ray Spectroscopy Techniques
- Planetary Science and Exploration
- Digital Holography and Microscopy
- Enzyme Structure and Function
- Advancements in Photolithography Techniques
- Nuclear Physics and Applications
- Advanced MRI Techniques and Applications
- Particle Accelerators and Free-Electron Lasers
- X-ray Diffraction in Crystallography
- Isotope Analysis in Ecology
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Atmospheric Ozone and Climate
- Hydrocarbon exploration and reservoir analysis
- Advanced Fluorescence Microscopy Techniques
- Laser-Plasma Interactions and Diagnostics
- Geochemistry and Geologic Mapping
- Advanced Materials Characterization Techniques
Argonne National Laboratory
2014-2023
Northwestern University
2014-2023
University of Arizona
2022
Institut de l'Information Scientifique et Technique
2022
New York University Press
2010-2022
University of the Sunshine Coast
2022
Brookhaven National Laboratory
1996-2021
Advanced Photonix (United States)
2021
Hewlett-Packard (United States)
2002-2020
Keysight Technologies (United States)
2018-2020
The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. preliminary examination these samples shows that the nonvolatile portion is an unequilibrated assortment materials have both presolar solar system origin. contains abundance silicate grains are much larger than predictions interstellar grain models, many high-temperature minerals appear formed in inner regions nebula. Their presence a proves formation included...
Analysis of tomographic datasets at synchrotron light sources (including X-ray transmission tomography, fluorescence microscopy and diffraction tomography) is becoming progressively more challenging due to the increasing data acquisition rates that new technologies in detectors enable. The next generation facilities are currently under design or construction throughout world will provide diffraction-limited expected boost current by several orders magnitude, stressing need for development...
Organics found in comet 81P/Wild 2 samples show a heterogeneous and unequilibrated distribution abundance composition. Some organics are similar, but not identical, to those interplanetary dust particles carbonaceous meteorites. A class of aromatic-poor organic material is also present. The rich oxygen nitrogen compared with meteoritic organics. Aromatic compounds present, the tend be relatively poorer aromatics than meteorites particles. presence deuterium nitrogen-15 excesses suggest that...
Coherent x-ray diffraction microscopy is a method of imaging nonperiodic isolated objects at resolutions limited, in principle, by only the wavelength and largest scattering angles recorded. We demonstrate with high resolution all three dimensions, as determined quantitative analysis reconstructed volume images. These images are retrieved from three-dimensional data using no priori knowledge about shape or composition object, which has never before been demonstrated on object. also construct...
We have used the method of x-ray diffraction microscopy to image complex-valued exit wave an intact and unstained yeast cell. The images freeze-dried cell, obtained by using 750-eV x-rays from different angular orientations, portray several cell's major internal components 30-nm resolution. good agreement among independently recovered structures demonstrates accuracy imaging technique. To obtain best possible reconstructions, we implemented procedures for handling noisy incomplete data,...
We present spatial coherence measurements of extreme-ultraviolet light generated using the process high-harmonic upconversion a femtosecond laser. Using phase-matched hollow-fiber geometry, beam is found to exhibit essentially full coherence. The this laser-like EUV source demonstrated by recording Gabor holograms small objects. This work demonstrates capability do holography tabletop experimental setup. Such an source, with low divergence and high coherence, can be used for experiments such...
A method is described whereby a sequence of X‐ray images at closely spaced photon energies acquired using scanning transmission microscope, and aligned. Near‐edge absorption spectra can then be obtained both from large, irregular regions, regions as small the spatial resolution microscope (about 40 nm in examples shown here). The use technique illustrated examination layered polymer film, micrometeorite section, an interplanetary dust particle section.
Small‐scale heterogeneity of organic carbon (C) forms in soils is poorly quantified since appropriate analytical techniques were not available up to now. Specifically, tools for the identification functional groups on surface micrometer‐sized black C particles Scanning Transmission X‐ray Microscopy (STXM) using synchrotron radiation was used conjunction with Near‐Edge Absorption Fine Structure (NEXAFS) spectroscopy investigate nano‐scale distribution (50‐nm resolution) and compared...
Fourier transform x-ray holography has been used to image gold test objects with submicrometer structure, resolving features as small 60 nanometers. The hologram-recording instrument uses coherent 3.4-nanometer radiation from the soft undulator beamline X1A at National Synchrotron Light Source. specimen be imaged is placed near first-order focal spot produced by a Fresnel zone plate; other orders, chiefly zeroth, illuminate specimen. wave scattered interferes spherical reference spot,...
The study of trace metal cycling by aquatic protists is limited current analytical techniques. Standard "bulk" element analysis techniques that rely on physical separations to concentrate cells for cannot separate from co-occurring detrital material or other differing taxonomy trophic function. Here we demonstrate the ability a synchrotron-based X-ray fluorescence (SXRF) microprobe quantify elements Si, Mn, Fe, Ni, and Zn in individual protist cells. This technique distinguishes between...
We present comprehensive measurements of the C (carbon) K edge near-edge X-ray absorption (NEXAFS) spectra all 20 amino acids commonly occurring in nature. Qualitative trends among with similar chemical character are identified and spectral features compared extensive ab initio calculations. The contributions individual units substitutional groups have been determined to explore their fingerprinting using building block concept. Several such found. Two that give particularly clear 1s NEXAFS...
Natural organic matter (NOM) is a highly active component of soils and sediments, plays an important role in global C cycling. However, NOM has defied molecular‐level structural characterization, owing to variations along the decomposition continuum its existence as functionalized polyelectrolytes. We conducted comprehensive systematic overview spectral signatures peak positions major molecules that occur part using near‐edge x‐ray absorption fine structure (NEXAFS) spectroscopy. The spectra...
In vascular plants, the polysaccharide-based walls of water-conducting cells are strengthened by impregnation with polyphenolic polymer lignin. The fine-scale patterning lignin deposition in is shown here to vary phylogenetically across plants. extent which water transport xylem can be modified response changes ionic content sap also correlation variation lignification patterns, consistent proposed mechanism for hydraulic through size change middle-lamella pectins. This covariation suggests...
Significance X-ray fluorescence microscopy provides unparalleled sensitivity for measuring the distribution of trace elements in many-micrometer-thick specimens, whereas ptychography offers a path to imaging weakly fluorescing biological ultrastructure at beyond-focusing-optic resolution. We demonstrate here first time, our knowledge, combination and frozen-hydrated specimens cryogenic temperatures, with excellent structural chemical preservation. This combined approach will have significant...
Details are provided of the algorithm used for reconstruction yeast cell images in recent demonstration diffraction microscopy by Shapiro, Thibault, Beetz, Elser, Howells, Jacobsen, Kirz, Lima, Miao, Nieman & Sayre [Proc. Natl Acad. Sci. USA (2005), 102, 15343–15346]. Two refinements iterative constraint-based scheme developed to address current experimental realities this imaging technique, which include missing central data and noise. A constrained power operator is defined whose...
Hard X-ray fluorescence microscopy is one of the most sensitive techniques for performing trace elemental analysis biological samples such as whole cells and tissues. Conventional sample preparation methods usually involve dehydration, which removes cellular water may consequently cause structural collapse, or invasive processes embedding. Radiation-induced artifacts also become an issue, particularly spatial resolution increases beyond sub-micrometer scale. To allow imaging under hydrated...
X-ray fluorescence tomography promises to map elemental distributions in unstained and unfixed biological specimens three dimensions at high resolution sensitivity, offering unparalleled insight medical, biological, environmental sciences. of has been viewed as impractical-and perhaps even impossible for routine application-due the large time required scanning significant radiation dose delivered specimen during imaging process. Here, we demonstrate submicron a whole specimen, quantifying...
Abstract— Synchrotron‐based soft X‐ray micro‐analysis was performed on particles extracted from the Stardust aerogel collector in order to obtain detailed organic functional group information any solids captured as part of Principal Examination suite analyses for samples comet 81P/Wild 2. It is observed that cometary carbon present a number different manifestations and often intimately associated with silicates. Carbon absorption near edge structure (XANES) spectra reveal considerable...