The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform
Cheng Wang - One of the best experts on this subject based on the ideXlab platform.
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Resonant Soft X-Ray scattering for polymer materials
European Polymer Journal, 2016Co-Authors: Michael A. Brady, Cheng WangAbstract:Abstract Resonant Soft X-Ray Scattering (RSoXS) was developed over the last a few years, and the first dedicated resonant Soft X-Ray scattering beamline for Soft materials was constructed at the Advanced Light Source, LBNL. RSoXS combines Soft X-Ray spectroscopy with X-Ray scattering and thus offers statistical information for 3D chemical morphology over a large length scale range from nanometers to micrometers. Using RSoXS to characterize multi-length scale Soft materials with heterogeneous chemical structures, we have demonstrated that Soft X-Ray scattering is a unique complementary technique to conventional hard X-Ray and neutron scattering. Its unique chemical sensitivity, large accessible size scale, molecular bond orientation sensitivity with polarized X-Rays, and high coherence have shown great potential for chemically specific structural characterization for many classes of materials.
Adam P. Hitchcock - One of the best experts on this subject based on the ideXlab platform.
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Introduction of Soft X-Ray spectromicroscopy as an advanced technique for plant biopolymers research
PLoS ONE, 2015Co-Authors: Chithra Karunakaran, Colleen R. Christensen, Cedric Gaillard, Rachid Lahlali, Lisa M. Blair, Vijayan Perumal, Shea S. Miller, Adam P. HitchcockAbstract:Soft X-Ray absorption spectroscopy coupled with nano-scale microscopy has been widely used in material science, environmental science, and physical sciences. In this work, the advantages of Soft X-Ray absorption spectromicroscopy for plant biopolymer research were demonstrated by determining the chemical sensitivity of the technique to identify common plant biopolymers and to map the distributions of biopolymers in plant samples. The chemical sensitivity of Soft X-Ray spectroscopy to study biopolymers was determined by recording the spectra of common plant biopolymers using Soft X-Ray and Fourier Transform mid Infrared (FT-IR) spectroscopy techniques. The Soft X-Ray spectra of lignin, cellulose, and polygalacturonic acid have distinct spectral features. However, there were no distinct differences between cellulose and hemicellulose spectra. Mid infrared spectra of all biopolymers were unique and there were differences between the spectra of water soluble and insoluble xylans. The advantage of nano-scale spatial resolution exploited using Soft X-Ray spectromicroscopy for plant biopolymer research was demonstrated by mapping plant cell wall biopolymers in a lentil stem section and compared with the FT-IR spectromicroscopy data from the same sample. The Soft X-Ray spectromicroscopy enables mapping of biopolymers at the sub-cellular (similar to 30 nm) resolution whereas, the limited spatial resolution in the micron scale range in the FT-IR spectromicroscopy made it difficult to identify the localized distribution of biopolymers. The advantages and limitations of Soft X-Ray and FT-IR spectromicroscopy techniques for biopolymer research are also discussed.
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Soft X-Ray spectromicroscopy and ptychography
Journal of Electron Spectroscopy and Related Phenomena, 2015Co-Authors: Adam P. HitchcockAbstract:Abstract Instrumentation and current capabilities of Soft X-Ray (50–2000 eV) spectromicroscopy are outlined with examples from recently published and some new work. Four common techniques are treated—transmission X-Ray microscopy (TXM), scanning transmission X-Ray microscopy (STXM), X-Ray photoemission electron microscopy (XPEEM) and scanning photoemission microscopy (SPEM). I also present a fifth, emerging technique, that of Soft X-Ray spectro-ptychography which has significantly improved spatial resolution and provides new contrast mechanisms. Perspectives for near future (5–10 years) evolution of Soft X-Ray spectromicroscopy are outlined based on current trends and instrumentation under development.
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Zone plate focused Soft X-Ray lithography
Applied Physics A, 2011Co-Authors: Adam F. G. Leontowich, Adam P. HitchcockAbstract:The zone plate focused Soft X-Rays of a scanning transmission X-Ray microscope have been used to pattern poly(methyl methacrylate) and poly(dimethylglutarimide) films by a direct write method which is analogous to lithography with a focused electron beam. The lithographic characteristics of both polymers have been determined for 300 eV X-Rays. With low doses (1 MGy), developed lines 40±5 nm wide were created in poly(methyl methacrylate). At higher doses an exposure spreading phenomenon substantially increases the lateral dimensions of the developed patterns. The spreading mechanism has been identified as the point-spread function of the zone plate lens. The performance of focused Soft X-Ray lithography is compared to other direct write methods. The practicality of a dedicated focused Soft X-Ray writer instrument is discussed.
Sophie Kazamias - One of the best experts on this subject based on the ideXlab platform.
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Fourier-limited seeded Soft X-Ray laser pulse
Optics Letters, 2010Co-Authors: O Guilbaud, D Ros, K Cassou, F. Tissandier, Jean-philippe Goddet, Maxime Ribière, Stéphane Sebban, Julien Gautier, Denis Joyeux, Sophie KazamiasAbstract:We present what we believe to be the first measurement of the spectral properties of a Soft X-Ray laser seeded by a high-order harmonic beam. Using an interferometric method, the spectral profile of a seeded Ni-like krypton Soft X-Ray laser (32.8 nm) generated by optical field ionization has been experimentally determined, and the shortest possible pulse duration has been deduced. The source exhibits a Voigt spectral profile with an FWHM of 3.1±0.3 mÅ, leading to a Fourier-transform pulse duration of 4.7 ps. This value is comparable with the upper limit of the Soft X-Ray pulse duration determined by experimentally investigating the gain dynamics, from which we conclude that the source has reached the Fourier limit. The measured bandwidth is in good agreement with the predictions of a radiative transfer code, including gain line narrowing and saturation rebroadening.
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Homogeneous focusing with a transient Soft X-Ray laser for irradiations experiments
Optics Communications, 2006Co-Authors: Sophie Kazamias, K Cassou, Annie Klisnick, David Ros, Olivier Guilbaud, Fabien Ple, Gérard Jamelot, Bedrich Rus, M. Koslova, M. StupkaAbstract:We report the work done on a transient Soft X-Ray laser (SXRL) beam to deliver a proper extreme UV irradiation source for applications. The same optical tool was first demonstrated on a quasi stationnary state (QSS) Soft X-Ray laser at the PALS Institute in Prague. The problem set by the transient Soft X-Ray laser developed by the LIXAM at the LULI installation in Palaiseau is more crucial, first because the beam spatial profile is more irregular secondly because high repetition rate Soft X-Ray laser facilities in the future are based on this SXRL type. The spots obtained show a 20 micron average diameter and a rather homogeneous and smooth profile that make them a realistic irradiation source to interact with targets requiring relatively high fluence (near 1 J/cm2) or intensity (near 1011 W/cm2) in the extreme UV domain.
A. L. D. Kilcoyne - One of the best experts on this subject based on the ideXlab platform.
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Resonant Soft X-Ray scattering from structured polymer nanoparticles
Applied Physics Letters, 2006Co-Authors: Tohru Araki, Harald Ade, Jeffrey M. Stubbs, Donald C. Sundberg, G. E. Mitchell, Jeffrey B. Kortright, A. L. D. KilcoyneAbstract:The application of resonant Soft X-Ray scattering to chemically heterogeneous Soft condensed matter materials is presented. Two structured styrene-acrylic polymer composite latex particles ∼230nm in diameter were utilized to delineate the potential utility of this technique. Angular scans at photon energies corresponding to strong scattering contrast between specific chemical moieties made it possible to infer the effective radii that correspond to the two polymer phases in the nanoparticles. The results show that resonant Soft X-Ray scattering should be a powerful complementary tool to neutron and hard X-Ray scattering for the characterization of structured Soft condensed matter nanomaterials.
Jinghua Guo - One of the best experts on this subject based on the ideXlab platform.
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In-situ/operando Soft X-Ray spectroscopy characterization of energy and catalytic materials
Solar Energy Materials and Solar Cells, 2020Co-Authors: Yi-sheng Liu, Xuefei Feng, Per-anders Glans, Jinghua GuoAbstract:Abstract The capabilities of Soft X-Ray absorption (XAS), Soft X-Ray emission spectroscopy (XES), resonant inelastic Soft X-Ray scattering (RIXS), and their application to characterization of solar energy materials are presented. We have discussed some recent developments of in-situ Soft X-Ray spectroscopy cells, which enable the investigation of critical solid/liquid or solid/gas interfaces in chemical and electrochemical processes under real-world practical conditions. In particular, in-situ Soft X-Ray spectroscopies can be utilized to probe the formation of intermediate species, charge separation upon illumination of sunlight and electron transfer to the interfacial reactions. A number of examples using Soft X-Ray spectroscopies to study these solar energy and catalytic materials are discussed to demonstrate how these powerful characterization tools could be helpful to further understand the energy conversion and energy storage systems.
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Soft-X-Ray spectroscopy experiment of liquids
Journal of Vacuum Science & Technology A: Vacuum Surfaces and Films, 2007Co-Authors: Jinghua Guo, Tyler Tong, Lukas Svec, Chung-li Dong, Jau-wern ChiouAbstract:The authors show an experimental setup to carry out Soft-X-Ray fluorescence spectroscopy of liquids under an ultrahigh vacuum (UHV) condition. The flow liquid cell has a window to attain compatibility with UHV conditions of the fluorescence spectrometer and synchrotron radiation beamline. The Soft-X-Ray photons enter the liquid cell through a 100nm thick silicon nitride window, and the emitted Soft x rays exit through the same window to be detected by photon diode and microchannel plate detectors. This setup allows liquids and, in particular, liquid-solid interfaces to be studied. Such a liquid cell has been used to study the electronic structure of a variety of systems ranging from water solutions of inorganic salts and nanomaterials under wet conditions.
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Soft-X-Ray spectroscopy study of nanoscale materials
Physical Chemistry of Interfaces and Nanomaterials IV, 2005Co-Authors: Jinghua GuoAbstract:The ability to control the particle size and morphology of nanoparticles is of crucial importance nowadays both from a fundamental and industrial point of view considering the tremendous amount of high-tech applications. Controlling the crystallographic structure and the arrangement of atoms along the surface of nanostructured material will determine most of its physical properties. In general, electronic structure ultimately determines the properties of matter. Soft X-Ray spectroscopy has some basic features that are important to consider. X-Ray is originating from an electronic transition between a localized core state and a valence state. As a core state is involved, elemental selectivity is obtained because the core levels of different elements are well separated in energy, meaning that the involvement of the inner level makes this probe localized to one specific atomic site around which the electronic structure is reflected as a partial density-of-states contribution. The participation of valence electrons gives the method chemical state sensitivity and further, the dipole nature of the transitions gives particular symmetry information. The new generation synchrotron radiation sources producing intensive tunable monochromatized Soft X-Ray beams have opened up new possibilities for Soft X-Ray spectroscopy. The introduction of selectively excited Soft X-Ray emission has opened a new field of study by disclosing many new possibilities of Soft X-Ray resonant inelastic scattering. In this paper, some recent findings regarding Soft X-Ray absorption and emission studies of various nanostructured systems are presented.
