The Experts below are selected from a list of 51867 Experts worldwide ranked by ideXlab platform
Ian K. Robinson - One of the best experts on this subject based on the ideXlab platform.
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Nanoparticle Structure by Coherent X-Ray Diffraction
Journal of the Physical Society of Japan, 2013Co-Authors: Ian K. RobinsonAbstract:This review examines the physical reasons why nanoparticles differ in structure from the bulk. Certain simple properties of nanoparticles are explained through these structural differences. A powerful method of measuring the three dimensional structure of nanoparticles, Coherent X-Ray diffraction (CXD), is introduced. A key experiment is described that uses CXD to study the redistribution of strains on the surface of a Au nanocrystal. Some future perspectives are discussed in conclusion.
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Coherent X-Ray diffraction imaging of paint pigment particles by scanning a phase plate modulator
New Journal of Physics, 2011Co-Authors: Bo Chen, Yong S. Chu, Felisa Berenguer, Fucai Zhang, Richard Bean, Cameron M. Kewish, Joan Vila-comamala, John M. Rodenburg, Ian K. RobinsonAbstract:We have implemented a Coherent X-Ray diffraction imaging technique that scans a phase plate to modulate wave-fronts of the X-Ray beam transmitted by samples. The method was applied to measure a decorative alkyd paint containing iron oxide red pigment particles. By employing an iterative algorithm for wave-front modulation phase retrieval, we obtained an image of the paint sample that shows the distribution of the pigment particles and is consistent with the result obtained from a transmission X-Ray microscope. The technique has been experimentally proven to be a feasible Coherent X-Ray imaging method with about 120 nm spatial resolution and was shown to work well with industrially relevant specimens.
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Imaging of complex density in silver nanocubes by Coherent X-Ray diffraction
New Journal of Physics, 2010Co-Authors: Ross Harder, M Liang, Yugang Sun, Younan Xia, Ian K. RobinsonAbstract:When using Coherent X-Rays to perform lensless imaging, it is the complex wave field exiting the sample or, in the case of the Bragg geometry, the deformed electron density distribution of a crystal, that is being sought. For most samples, to some extent, the image will be complex, containing both an amplitude and phase variation across the sample. We have developed versions of the hybrid input-output (HIO) and error reduction (ER) algorithms that are very robust for the inversion to complex objects from three-dimensional (3D) Coherent X-Ray diffraction (CXD) data measured around a Bragg spot of a small crystal. The development and behavior of these algorithms will be discussed in the context of inverting a 3D CXD pattern measured around a (111) Bragg spot of a silver nanocube.
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Coherent X-Ray diffraction from collagenous soft tissues
P NATL ACAD SCI USA, 2009Co-Authors: Ian K. RobinsonAbstract:Coherent X-Ray diffraction has been applied in the imaging of inorganic materials with great success. However, its application to biological specimens has been limited to some notable exceptions, due to the induced radiation damage and the extended nature of biological samples, the last limiting the application of most part of the phasing algorithms. X-Ray ptychography, still under development, is a good candidate to overcome such difficulties and become a powerful imaging method for biology. We describe herein the feasibility of applying ptychography to the imaging of biological specimens, in particular collagen rich samples. We report here speckles in diffraction patterns from soft animal tissue, obtained with an optimized small angle X-Ray setup that exploits the natural coherence of the beam. By phasing these patterns, dark field images of collagen within tendon, skin, bone, or cornea will eventually be obtained with a resolution of 60-70 nm. We present simulations of the contrast mechanism in collagen based on atomic force microscope images of the samples. Simulations confirmed the 'speckled' nature of the obtained diffraction patterns. Once inverted, the patterns will show the disposition and orientation of the fibers within the tissue, by enhancing the phase contrast between protein and no protein regions of the sample. Our work affords the application of the most innovative Coherent X-Ray diffraction tools to the study of biological specimens, and this approach will have a significant impact in biology and medicine because it overcomes many of the limits of current microscopy techniques.
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Imaging of Domain Structures by Coherent X-Ray Diffraction
Frontiers in Optics 2009 Laser Science XXV Fall 2009 OSA Optics & Photonics Technical Digest, 2009Co-Authors: Ian K. RobinsonAbstract:Following successful ab initio imaging small objects by Coherent X-Ray Diffraction using their three-dimensional diffraction patterns, comes the harder problem of domain structures. This talk summarises progress solving them using the new method of X-Ray ptychography.
Tetsuya Ishikawa - One of the best experts on this subject based on the ideXlab platform.
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Visualization of a Mammalian Mitochondrion by Coherent X-Ray Diffractive Imaging.
Scientific Reports, 2017Co-Authors: Yoonhee Kim, Tetsuya Ishikawa, Chan Kim, Ou Young Kwon, Daewoong Nam, Sangsoo Kim, Jaehyun Park, Sunam Kim, Marcus Gallagher-jones, Yoshiki Kohmura, Tetsuya IshikawaAbstract:We report a three dimensional (3D) quantitative visualization of a mammalian mitochondrion by Coherent X-Ray diffractive imaging (CXDI) using synchrotron radiation. The internal structures of a mitochondrion from a mouse embryonic fibroblast cell line (NIH3T3) were visualized by tomographic imaging at approximately 60 nm resolution without the need for sectioning or staining. The overall structure consisted of a high electron density region, composed of the outer and inner membranes and the cristae cluster, which enclosed the lower density mitochondrial matrix. The average mass density of the mitochondrion was about 1.36 g/cm3. Sectioned images of the cristae reveal that they have neither a baffle nor septa shape but were instead irregular. In addition, a high resolution, about 14 nm, 2D projection image was captured of a similar mitochondrion with the aid of strongly scattering Au reference objects. Obtaining 3D images at this improved resolution will allow CXDI to be an effective and nondestructive method for investigating the innate structure of mitochondria and other important life supporting organelles.
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beyond crystallography diffractive imaging using Coherent x ray light sources
Science, 2015Co-Authors: Jianwei Miao, Tetsuya Ishikawa, I K Robinson, Margaret M MurnaneAbstract:X-Ray crystallography has been central to the development of many fields of science over the past century. It has now matured to a point that as long as good-quality crystals are available, their atomic structure can be routinely determined in three dimensions. However, many samples in physics, chemistry, materials science, nanoscience, geology, and biology are noncrystalline, and thus their three-dimensional structures are not accessible by traditional X-Ray crystallography. Overcoming this hurdle has required the development of new Coherent imaging methods to harness new Coherent X-Ray light sources. Here we review the revolutionary advances that are transforming X-Ray sources and imaging in the 21st century.
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Development of Coherent X‐ray Diffraction Apparatus with Kirkpatrick‐Baez Mirror Optics
2011Co-Authors: Yukio Takahashi, Yoshinori Nishino, Ryosuke Tsutsumi, Hidekazu Mimura, Satoshi Matsuyama, Tetsuya Ishikawa, Kazuto YamauchiAbstract:To realize Coherent x‐ray diffraction microscopy with higher spatial resolution, it is necessary to increase the density of x‐ray photons illuminated onto the sample. In this study, we developed a Coherent x‐ray diffraction apparatus with Kirkpatrick‐Baez mirror optics. By using mirrors fabricated by elastic emission machining, a high‐density Coherent x‐ray beam was produced. In a demonstration experiment using a silver nanocube as a sample, a high‐contrast Coherent x‐ray diffraction pattern was observed over a wide‐q range. This proves that both the density and the degree of coherence of the focused beam were high.
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development of incident x ray flux monitor for Coherent x ray diffraction microscopy
Journal of Physics: Conference Series, 2009Co-Authors: Yukio Takahashi, Tetsuya Ishikawa, Kazuto Yamauchi, Hayato Furukawa, Hideto Kubo, Eiichiro Matsubara, Yoshinori NishinoAbstract:An incident X-Ray flux monitor for Coherent X-Ray diffraction microscopy was developed. The intensities of X-Rays passing through the sample were measured using an X-Ray photodiode, with the simultaneous measurement of the X-Ray diffraction intensities of the sample. As a result of the normalization of the X-Ray diffraction intensities by the incident X-Ray flux determined from the monitor, the fluctuation of the speckle intensities was successfully suppressed.
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Observation of electromigration in a Cu thin line by in situ Coherent X-Ray diffraction microscopy
Journal of Applied Physics, 2009Co-Authors: Yukio Takahashi, Yoshinori Nishino, Tetsuya Ishikawa, Kazuto Yamauchi, Hayato Furukawa, Hideto Kubo, Eiichiro MatsubaraAbstract:Electromigration (EM) in a 1‐μm-thick Cu thin line was investigated by in situ Coherent X-Ray diffraction microscopy (CXDM). Characteristic X-Ray speckle patterns due to both EM-induced voids and thermal deformation in the thin line were observed in the Coherent X-Ray diffraction patterns. Both parts of the voids and the deformation were successfully visualized in the images reconstructed from the diffraction patterns. This result not only represents the first demonstration of the visualization of structural changes in metallic materials by in situ CXDM but is also an important step toward studying the structural dynamics of nanomaterials using X-Ray free-electron lasers in the near future.
Yoshinori Nishino - One of the best experts on this subject based on the ideXlab platform.
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Coherent X-Ray zoom condenser lens for diffractive and scanning microscopy.
Optics express, 2013Co-Authors: Takashi Kimura, Kazuto Yamauchi, Satoshi Matsuyama, Yoshinori NishinoAbstract:We propose a Coherent X-Ray zoom condenser lens composed of two-stage deformable Kirkpatrick-Baez mirrors. The lens delivers Coherent X-Rays with a controllable beam size, from one micrometer to a few tens of nanometers, at a fixed focal position. The lens is suitable for diffractive and scanning microscopy. We also propose non-scanning Coherent diffraction microscopy for extended objects by using an apodized focused beam produced by the lens with a spatial filter. The proposed apodized-illumination method will be useful in highly efficient imaging with ultimate storage ring sources, and will also open the way to single-shot Coherent diffraction microscopy of extended objects with X-Ray free-electron lasers.
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Development of Coherent X‐ray Diffraction Apparatus with Kirkpatrick‐Baez Mirror Optics
2011Co-Authors: Yukio Takahashi, Yoshinori Nishino, Ryosuke Tsutsumi, Hidekazu Mimura, Satoshi Matsuyama, Tetsuya Ishikawa, Kazuto YamauchiAbstract:To realize Coherent x‐ray diffraction microscopy with higher spatial resolution, it is necessary to increase the density of x‐ray photons illuminated onto the sample. In this study, we developed a Coherent x‐ray diffraction apparatus with Kirkpatrick‐Baez mirror optics. By using mirrors fabricated by elastic emission machining, a high‐density Coherent x‐ray beam was produced. In a demonstration experiment using a silver nanocube as a sample, a high‐contrast Coherent x‐ray diffraction pattern was observed over a wide‐q range. This proves that both the density and the degree of coherence of the focused beam were high.
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development of incident x ray flux monitor for Coherent x ray diffraction microscopy
Journal of Physics: Conference Series, 2009Co-Authors: Yukio Takahashi, Tetsuya Ishikawa, Kazuto Yamauchi, Hayato Furukawa, Hideto Kubo, Eiichiro Matsubara, Yoshinori NishinoAbstract:An incident X-Ray flux monitor for Coherent X-Ray diffraction microscopy was developed. The intensities of X-Rays passing through the sample were measured using an X-Ray photodiode, with the simultaneous measurement of the X-Ray diffraction intensities of the sample. As a result of the normalization of the X-Ray diffraction intensities by the incident X-Ray flux determined from the monitor, the fluctuation of the speckle intensities was successfully suppressed.
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Observation of electromigration in a Cu thin line by in situ Coherent X-Ray diffraction microscopy
Journal of Applied Physics, 2009Co-Authors: Yukio Takahashi, Yoshinori Nishino, Tetsuya Ishikawa, Kazuto Yamauchi, Hayato Furukawa, Hideto Kubo, Eiichiro MatsubaraAbstract:Electromigration (EM) in a 1‐μm-thick Cu thin line was investigated by in situ Coherent X-Ray diffraction microscopy (CXDM). Characteristic X-Ray speckle patterns due to both EM-induced voids and thermal deformation in the thin line were observed in the Coherent X-Ray diffraction patterns. Both parts of the voids and the deformation were successfully visualized in the images reconstructed from the diffraction patterns. This result not only represents the first demonstration of the visualization of structural changes in metallic materials by in situ CXDM but is also an important step toward studying the structural dynamics of nanomaterials using X-Ray free-electron lasers in the near future.
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Three-dimensional visualization of a human chromosome using Coherent X-Ray diffraction.
Physical review letters, 2009Co-Authors: Yoshinori Nishino, Yukio Takahashi, Tetsuya Ishikawa, Naoko Imamoto, Kazuhiro MaeshimaAbstract:Coherent X-Ray diffraction microscopy is a lensless phase-contrast imaging technique with high image contrast. Although electron tomography allows intensive study of the three-dimensional structure of cellular organelles, it has inherent difficulty with thick objects. X rays have the unique benefit of allowing noninvasive analysis of thicker objects and high spatial resolution. We observed an unstained human chromosome using Coherent X-Ray diffraction. The reconstructed images in two or three dimensions show an axial structure, which has not been observed under unstained conditions.
I. A. Vartanyants - One of the best experts on this subject based on the ideXlab platform.
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Dynamical effects in Bragg Coherent X-Ray diffraction imaging of finite crystals
Physical Review B, 2017Co-Authors: Anatoly Shabalin, Oleksandr Yefanov, V. L. Nosik, V. A. Bushuev, I. A. VartanyantsAbstract:We present simulations of Bragg Coherent X-Ray Diffractive Imaging (CXDI) data from finite crystals in the frame of the dynamical theory of X-Ray diffraction. The developed approach is based on numerical solution of modified Takagi-Taupin equations and can be applied for modeling of a broad range of X-Ray diffraction experiments with finite three-dimensional crystals of arbitrary shape also in the presence of strain. We performed simulations for nanocrystals of a cubic and hemispherical shape of different sizes and provided a detailed analysis of artifacts in the Bragg CXDI reconstructions introduced by the dynamical diffraction. A convenient way to treat effects of refraction and absorption supported by analytical derivations is described. Our results elucidate limitations for the kinematical approach in the Bragg CXDI and suggest a natural criterion to distinguish between kinematical and dynamical cases in Coherent X-Ray diffraction on a finite crystal.
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Coherent X-Ray Diffraction Imaging of Nanostructures
arXiv: Mesoscale and Nanoscale Physics, 2013Co-Authors: I. A. Vartanyants, Oleksandr YefanovAbstract:We present here an overview of Coherent X-Ray Diffraction Imaging (CXDI) with its application to nanostructures. This imaging approach has become especially important recently due to advent of X-Ray Free-Electron Lasers (XFEL) and its applications to the fast developing technique of serial X-Ray crystallography. We start with the basic description of Coherent scattering on the finite size crystals. The difference between conventional crystallography applied to large samples and Coherent scattering on the finite size samples is outlined. The formalism of Coherent scattering from a finite size crystal with a strain field is considered. Partially Coherent illumination of a crystalline sample is developed. Recent experimental examples demonstrating applications of CXDI to the study of crystalline structures on the nanoscale, including experiments at FELs, are also presented.
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Coherent X‐ray nanodiffraction on single GaAs nanowires
physica status solidi (a), 2011Co-Authors: J. Gulden, Oleksandr Yefanov, Adrian P. Mancuso, S. O. Mariager, J. Baltser, Peter Krogstrup, J. Patommel, Manfred Burghammer, Robert Feidenhans'l, I. A. VartanyantsAbstract:Coherent X-Ray nanodiffraction was applied to investigate single GaAs nanowires. Using the nanofocus hard X-Ray setup at ID13 of the ESRF, the diffraction signal from isolated nanowires was measured. The diffraction patterns were recorded for different rotations of the sample. These diffraction patterns were then combined to yield three-dimensional information around a Wurzite [101] Bragg peak.
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Coherent X-Ray imaging of defects in colloidal crystals
Physical Review B, 2010Co-Authors: J. Gulden, Oleksandr Yefanov, Adrian P. Mancuso, V. V. Abramova, Jan Hilhorst, D. V. Byelov, Irina Snigireva, Anatoly Snigirev, Andrei V. Petukhov, I. A. VartanyantsAbstract:Coherent X-Ray diffractive imaging CXDI was applied to reveal the structure of colloidal crystals. The colloidal sample was illuminated by a Coherent X-Ray beam through a 7 m pinhole aperture. The resulting diffraction patterns contain several Bragg peaks and an additional interference structure between the peaks due to the Coherent illumination of a finite part of the sample. The inversion of these diffraction patterns reveals the arrangement of colloidal particles in a face-centered cubic fcc lattice as well as defects in the form of stacking faults in the 111 planes.
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Coherent X-Ray scattering and lensless imaging at the european XFEL facility
Journal of Synchrotron Radiation, 2007Co-Authors: I. A. Vartanyants, Ian K. Robinson, I. Mcnulty, C. David, Peter Wochner, Th. TschentscherAbstract:Coherent X-Ray diffraction imaging is a rapidly advancing form of lensless microscopy. The phase information of the diffraction pattern is embedded in a sufficiently sampled Coherent diffraction pattern. Using advanced computational methods, this diffraction pattern can be inverted to produce an image of a sample with diffraction-limited resolution. It is attractive to use high-power Coherent X-Ray beams produced by future X-Ray free-electron lasers for imaging nanoscale condensed matter, materials and biological samples. Here, the scientific case, requirements and the possible realisation of the Coherent X-Ray diffraction imaging beamlines at the European XFEL Facility are presented.
A. Locatelli - One of the best experts on this subject based on the ideXlab platform.
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Coherent X-Ray scattering in an XPEEM setup
Ultramicroscopy, 2020Co-Authors: T.o. Menteş, F. Genuzio, V. Schánilec, J. Sadílek, Nicolas Rougemaille, A. LocatelliAbstract:X-Ray photoemission electron microscopy has been one of the most productive X-Ray microscopy tools with chemical and magnetic sensitivity. We demonstrate that an existing XPEEM setup can be readily adapted to simultaneously perform Coherent X-Ray scattering measurements in reflectivity mode. Photon-in photon-out X-Ray scattering measurement provides the sensitivity to buried interfaces as well as the possibility to work under external fields not accessible in an electron-based measurement. XPEEM, in turn, greatly alleviates the difficulties associated with the reconstruction methods used in Coherent diffraction imaging. The combination of the two methods is demonstrated for a spin-ice lattice showing both chemical and magnetic contrast.
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Coherent X-Ray scattering in an XPEEM setup
Ultramicroscopy, 2020Co-Authors: T.o. Menteş, F. Genuzio, V. Schánilec, J. Sadílek, Nicolas Rougemaille, A. LocatelliAbstract:Abstract X-Ray photoemission electron microscopy, one of the most successful imaging tools at synchrotrons, is known to have limitations related to the application of external fields and to the short electron mean free path. In order to overcome such issues, we adapt an existing XPEEM instrument to simultaneously perform Coherent X-Ray scattering measurements in reflectivity mode, thus adding a complementary method to XPEEM. Photon-in photon-out X-Ray scattering provides the sensitivity to buried interfaces as well as the possibility to work under external fields, which is challenging when using charged particles for imaging. XPEEM, in turn, greatly alleviates the difficulties associated with the reconstruction methods used in Coherent diffraction imaging. The combination of the two methods is demonstrated for an artifical spin-ice lattice showing both chemical and magnetic contrast.