Download or read book Experimental Coherent X ray Diffractive Imaging written by Andreas Schropp and published by . This book was released on 2008 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coherent X ray diffractive imaging on the single cell level of microbial samples written by Robin Niklas Wilke and published by Göttingen University Press. This book was released on 2015 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its first experimental demonstration in 1999, Coherent X-Ray Diffractive Imaging has become one of the most promising high resolution X-Ray imaging techniques using coherent radiation produced by brilliant synchrotron storage rings. The ability to directly invert diffraction data with the help of advanced algorithms has paved the way for microscopic investigations and wave-field analyses on the spatial scale of nanometres without the need for inefficient imaging lenses. X-Ray phase contrast which is a measure of the electron density is an important contrast mode of soft biological specimens. For the case of many dominant elements of soft biological matter, the electron density can be converted into an effective mass density offering a unique quantitative information channel which may shed light on important questions such as DNA compaction in the bacterial nucleoid through ‚weighing with light‘. In this work X-Ray phase contrast maps have been obtained from different biological samples by exploring different methods. In particular, the techniques Ptychography and Waveguide-Holographic-Imaging have been used to obtain twodimensional and three-dimensional mass density maps on the single-cell-level of freeze-dried cells of the bacteria Deinococcus radiodurans, Bacillus subtilis and Bacillus thuringiensis allowing, for instance, to estimate the dry weight of the bacterial genome in a near native state. On top of this, reciprocal space information from coherent small angle X-Ray scattering (cellular Nano-Diffraction) of the fine structure of the bacterial cells has been recorded in a synergistic manner and has been analysed down to a resolution of about 2.3/nm exceeding current limits of direct imaging approaches. Furthermore, the dynamic range of present detector technology being one of the major limiting factors of ptychographic phasing of farfield diffraction data has been significantly increased. Overcoming this problem for the case of the very intense X-Ray beam produced by Kirkpatrick-Baez mirrors has been explored by using semi-transparent central stops.
Download or read book X Ray Diffraction written by Oliver H. Seeck and published by CRC Press. This book was released on 2015-02-10 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: High-resolution x-ray diffraction and scattering is a key tool for structure analysis not only in bulk materials but also at surfaces and buried interfaces from the sub-nanometer range to micrometers. This book offers an overview of diffraction and scattering methods currently available at modern synchrotron sources and illustrates bulk and interface investigations of solid and liquid matter with up-to-date research examples. It presents important characteristics of the sources, experimental set-up, and new detector developments. The book also considers future exploitation of x-ray free electron lasers for diffraction applications.
Download or read book Ultrafast Coherent Diffractive Imaging at FLASH written by H. N. Chapman and published by . This book was released on 2006 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using the FLASH facility we have demonstrated high-resolution coherent diffractive imaging with single soft-X-ray free-electron laser pulses [1]. The intense focused FEL pulse gives a high resolution low-noise coherent diffraction pattern of an object before that object turns into a plasma and explodes. Our experiments are an important milestone in the development of single-particle diffractive imaging with future X-ray free-electron lasers [2, 3]. Our apparatus provides a new and unique tool at FLASH to perform imaging of biological specimens beyond conventional radiation damage resolution limits [2, 4] and to acquire images of ultrafast processes initiated by an FEL pulse or other laser pulse. Coherent diffractive imaging is an ideal method for high-resolution ultrafast imaging with an FEL. Since no optical element is required, the method can in principle be scaled to atomic resolution with short enough wavelength. Spatial and temporal coherence are necessary to ensure that the scattered light waves from all positions across the sample are correlated when they interfere at the detector, giving rise to a coherent diffraction pattern that can be phased and inverted to give a high-resolution image of the sample. In contrast to crystals, where scattering from the many unit cells constructively interfere to give Bragg spots, the coherent diffraction pattern of a non-periodic object is continuous. Such a coherent diffraction pattern contains as much as twice the information content of the pattern of its crystallized periodic counterpart--exactly the amount of information needed to solve the phase problem and deterministically invert the pattern to yield an image of the object [5, 6]. The computer algorithm that performs this function replaces the analogue computations of a lens: summing the complex-valued amplitudes of scattered waves to form an image at a particular plane. Our experimental geometry is shown in Fig. 1. We focus a coherent X-ray pulse from the FLASH source onto the sample and record the far-field diffraction pattern of the object on an area detector (a direct-detection CCD chip) centered on the forward direction. The CCD is protected from destruction by the intense forward scattered beam by a mirror that reflects only the diffracted light onto the detector; the direct beam harmlessly passes through a hole in the mirror. The mirror is coated with a resonant X-ray multilayer coating. We fabricated the coating so that the layer period varies across the mirror in such a way that only in-band X-rays propagating from near the sample interaction point are efficiently reflected. In this way the mirror is a very effective filter that rejects noise such as broadband emission from the sample (e.g. when it turns into a plasma and explodes) and off-axis stray light from scattering and emission of beam line components. This arrangement was crucial here to record clean single-pulse diffraction patterns that could be phased and inverted.
Download or read book Nanoscale Photonic Imaging written by Tim Salditt and published by Springer Nature. This book was released on 2020-06-09 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book, edited and authored by a team of world-leading researchers, provides a broad overview of advanced photonic methods for nanoscale visualization, as well as describing a range of fascinating in-depth studies. Introductory chapters cover the most relevant physics and basic methods that young researchers need to master in order to work effectively in the field of nanoscale photonic imaging, from physical first principles, to instrumentation, to mathematical foundations of imaging and data analysis. Subsequent chapters demonstrate how these cutting edge methods are applied to a variety of systems, including complex fluids and biomolecular systems, for visualizing their structure and dynamics, in space and on timescales extending over many orders of magnitude down to the femtosecond range. Progress in nanoscale photonic imaging in Göttingen has been the sum total of more than a decade of work by a wide range of scientists and mathematicians across disciplines, working together in a vibrant collaboration of a kind rarely matched. This volume presents the highlights of their research achievements and serves as a record of the unique and remarkable constellation of contributors, as well as looking ahead at the future prospects in this field. It will serve not only as a useful reference for experienced researchers but also as a valuable point of entry for newcomers.
Download or read book Coherent X Ray Diffractive Imaging on the Single celll Level of Microbial Samples written by and published by . This book was released on 2014 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its first experimental demonstration in 1999, Coherent X-Ray Diffractive Imaging has become one of the most promising high resolution X-Ray imaging techniques using coherent radiation produced by brilliant synchrotron storage rings. The ability to directly invert diffraction data with the help of advanced algorithms has paved the way for microscopic investigations and wave-field analyses on the spatial scale of nanometres without the need for inefficient imaging lenses. X-Ray phase contrast which is a measure of the electron density is an important contrast mode of soft biological spe...
Download or read book X Ray Diffraction Imaging of Biological Cells written by Masayoshi Nakasako and published by Springer. This book was released on 2018-03-29 with total page 243 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, the author describes the development of the experimental diffraction setup and structural analysis of non-crystalline particles from material science and biology. Recent advances in X-ray free electron laser (XFEL)-coherent X-ray diffraction imaging (CXDI) experiments allow for the structural analysis of non-crystalline particles to a resolution of 7 nm, and to a resolution of 20 nm for biological materials. Now XFEL-CXDI marks the dawn of a new era in structural analys of non-crystalline particles with dimensions larger than 100 nm, which was quite impossible in the 20th century. To conduct CXDI experiments in both synchrotron and XFEL facilities, the author has developed apparatuses, named KOTOBUKI-1 and TAKASAGO-6 for cryogenic diffraction experiments on frozen-hydrated non-crystalline particles at around 66 K. At the synchrotron facility, cryogenic diffraction experiments dramatically reduce radiation damage of specimen particles and allow tomography CXDI experiments. In addition, in XFEL experiments, non-crystalline particles scattered on thin support membranes and flash-cooled can be used to efficiently increase the rate of XFEL pulses. The rate, which depends on the number density of scattered particles and the size of X-ray beams, is currently 20-90%, probably the world record in XFEL-CXDI experiments. The experiment setups and results are introduced in this book. The author has also developed software suitable for efficiently processing of diffraction patterns and retrieving electron density maps of specimen particles based on the diffraction theory used in CXDI.
Download or read book A Study on New Approaches in Coherent X ray Microscopy of Biological Specimens written by Klaus Giewekemeyer and published by Universitätsverlag Göttingen. This book was released on 2011 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of coherent x rays for microscopic imaging has seen a rapid and ongoing development within the past decade, driven by an increasing availability of highly brilliant and coherent sources worldwide. Accordingly, novel methods have been developed, which replace the microscope‘s objective lens by a numerical reconstruction scheme. The aim of the present work is to study how very recent experimental and algorithmic developments in the field can be implemented towards a highly sensitive and fully quantitative microscopy method for imaging of biological cells. To this end, different experimental approaches are studied, based on coherent far-field as well as near-field diffraction. At first, an application of the novel ptychographic imaging method to single biological cells is presented. In particular, it is demonstrated how weakly scattering biological specimens can be imaged with fully quantitative density contrast. Alongside, a sueccessful extension of the method towards soft x-ray energies is described.In the second part of the work it is shown how x-ray waveguides can be used as a point source for propagation-based microscopy of single cells in the hard x-ray regime. The specifically devised iterative reconstruction scheme allows for full quantitativity and high sensitivity and thus enables an application to single biological cells. The work contains a thorough introduction into the x-ray optical methods applied and aims at a useful and self-contained overview on aspects of signal and Fourier theory relevant for the used numerical propagation schemes.
Download or read book High Harmonic Generation for Coherent Diffractive Imaging written by Sven Teichmann and published by LAP Lambert Academic Publishing. This book was released on 2010-09 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sven Teichmann s doctorate features experimental work on a high-harmonic generation source and coherent diffractive imaging. High-harmonic generation allows generating coherent and laser-like extreme- ultraviolet and soft x-ray radiation based on the frequency-upconversion of laser light. A novel and successful approach of employing harmonic emission that consists of multiple harmonic orders is presented. This emission is utilized for coherent diffractive imaging by illuminating a sample of unknown structure, e.g. a membrane protein. The diffractive image of that sample is then processed by means of computational algorithms and the structure of the sample can be recovered. This innovative work of a very high level of technical achievement is considered as internationally significant by world leaders in the field of high- harmonic generation and may prove valuable particularly for time-resolved spectroscopy, sources of soft x-ray and extreme-ultraviolet radiation, and imaging based on harmonic emission.
Download or read book Soft X ray Coherence and Coherent Diffractive Imaging written by Mr. Ramon Rick and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The increased brightness of third-generation synchrotron X-ray sources using undulator insertion devices has opened up new fields for coherent lensless imaging experiments. While in the optical regime, coherent light sources allowed the pursuit of holography and imaging of non-periodic micron-sized objects, hard X-ray crystallography relied on the constructive interference of periodic lattices to image atomic structures. In the intermediate regime of soft X-rays, we now have the capability to coherently image non-periodic nanoscopic structures. Several elemental resonances, from carbon, nitrogen and oxygen to iron, cobalt and nickel, fall into the soft X-ray range of 100 eV to 1 keV. In order to pursue soft X-ray coherent imaging experiments at a synchrotron, an understanding of the origin of coherence is required. The first part of this work thus addresses the coherence properties of the undulator source. Imaging in this regime is both photon and spatial coherence thirsty and there is an inherent trade-off between these two resources. The incoherent source structure and the Heisenberg uncertainty principle lie at the heart of this matter. In reconstructing images of materials from intensity diffraction patterns, one faces the well-known phase problem. The second part of this work addresses two imaging techniques that were extended to the imaging of magnetic domains using X-ray magnetic circular dichroism. Fourier transform holography encodes the lost phase information into the intensity diffraction pattern, while multi-wavelength anomalous diffraction utilizes the energy dependence of the material's refractive index to regain the phase information. This latter method simplifies the sample preparation process and has the potential for coherent scanning microscopy.
Download or read book Hard X ray Microscopy Enhanced by Coherent Image Reconstruction written by Jakob Soltau and published by Universitätsverlag Göttingen. This book was released on 2022 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: X-ray microscopy is used to study the structure, dynamics and bulk properties of matter with high spatial resolutions. It is widely applied, from physics and chemistry to material and life sciences. In the past two decades, progress in X-ray microscopy was driven either by improvements in X-ray optics or by improvements in the image reconstruction by using algorithms as computational lenses. In this work both approaches are combined to exploit the advantages of X-ray imaging with a large numerical aperture and the advantages of coherent image reconstruction. It is shown that a combined X-ray microscope using both, advanced optics and algorithms, is neither limited by flawed optics nor by constraints imposed by reconstruction algorithms, which enables to go beyond current limits in resolution and applications. The thesis is structured in four parts. In the first part hard X-ray lenses, so called multilayer zone plates, are simulated to investigate volume diffraction effects within the multilayer structure, and to study the potential for smaller focus sizes and higher efficiencies. In the second part, the multilayer zone plates are characterized and implemented in an X-ray microscope. In the third part, a new imaging scheme is presented, which combines in-line holography and coherent diffractive imaging. This method overcomes the current resolution limit of in-line holography and can achieve super-resolution with respect to the numerical aperture of the illuminating beam. Finally, in the fourth part a multilayer zone plate is used as an objective lens with a known transfer function in a novel coherent full-field imaging experiment based on iterative phase retrieval, for high resolution and quantitative contrast.
Download or read book Experimental Phase Retrieval Using Coherent X ray Diffraction written by Adrian P. Mancuso and published by . This book was released on 2005 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coherent Diffractive Imaging Using Randomly Coded Masks written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We experimentally demonstrate an extension to coherent diffractive imaging that encodes additional information through the use of a series of randomly coded masks, removing the need for typical object-domain constraints while guaranteeing a unique solution to the phase retrieval problem. Phase retrieval is performed using a numerical convex relaxation routine known as "PhaseCut," an iterative algorithm known for its stability and for its ability to find the global solution, which can be found efficiently and which is robust to noise. As a result, the experiment is performed using a laser diode at 532.2 nm, enabling rapid prototyping for future X-ray synchrotron and even free electron laser experiments.
Download or read book Three dimensional Coherent X ray Diffractive Imaging of Whole Frozen hydrated Cells written by and published by . This book was released on 2015 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synchrotron Light Sources and Free Electron Lasers written by Eberhard J. Jaeschke and published by Springer. This book was released on 2016-05-27 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hardly any other discovery of the nineteenth century did have such an impact on science and technology as Wilhelm Conrad Röntgen’s seminal find of the X-rays. X-ray tubes soon made their way as excellent instruments for numerous applications in medicine, biology, materials science and testing, chemistry and public security. Developing new radiation sources with higher brilliance and much extended spectral range resulted in stunning developments like the electron synchrotron and electron storage ring and the freeelectron laser. This handbook highlights these developments in fifty chapters. The reader is given not only an inside view of exciting science areas but also of design concepts for the most advanced light sources. The theory of synchrotron radiation and of the freeelectron laser, design examples and the technology basis are presented. The handbook presents advanced concepts like seeding and harmonic generation, the booming field of Terahertz radiation sources and upcoming brilliant light sources driven by laser-plasma accelerators. The applications of the most advanced light sources and the advent of nanobeams and fully coherent x-rays allow experiments from which scientists in the past could not even dream. Examples are the diffraction with nanometer resolution, imaging with a full 3D reconstruction of the object from a diffraction pattern, measuring the disorder in liquids with high spatial and temporal resolution. The 20th century was dedicated to the development and improvement of synchrotron light sources with an ever ongoing increase of brilliance. With ultrahigh brilliance sources, the 21st century will be the century of x-ray lasers and their applications. Thus, we are already close to the dream of condensed matter and biophysics: imaging single (macro)molecules and measuring their dynamics on the femtosecond timescale to produce movies with atomic resolution.
Download or read book Multiscale X Ray Analysis of Biological Cells and Tissues by Scanning Diffraction and Coherent Imaging written by Jan-David Nicolas and published by Göttingen University Press. This book was released on 2019 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the intricate details of muscle contraction has a long-standing tradition in biophysical research. X-ray diffraction has been one of the key techniques to resolve the nanometer-sized molecular machinery involved in force generation. Modern, powerful X-ray sources now provide billions of X-ray photons in time intervals as short as microseconds, enabling fast time-resolved experiments that shed further light on the complex relationship between muscle structure and function. Another approach harnesses this power by repeatedly performing such an experiment at different locations in a sample. With millions of repeated exposures in a single experiment, X-ray diffraction can seamlessly be turned into a raster imaging method, neatly combining real- and reciprocal space information. This thesis has focused on the advancement of this scanning scheme and its application to soft biological tissue, in particular muscle tissue. Special emphasis was placed on the extraction of meaningful, quantitative structural parameters such as the interfilament distance of the actomyosin lattice in cardiac muscle. The method was further adapted to image biological samples on a range of scales, from isolated cells to millimeter-sized tissue sections. Due to the ‘photon-hungry’ nature of the technique, its full potential is often exploited in combination with full-field imaging techniques. From the vast set of microscopic tools available, coherent full-field X-ray imaging has proven to be particularly useful. This multimodal approach allows to correlate two- and three-dimensional images of cells and tissue with diffraction maps of structure parameters. With the set of tools developed in this thesis, scanning X-ray diffraction can now be efficiently used for the structural analysis of soft biological tissues with overarching future applications in biophysical and biomedical research.
Download or read book Nanobeam X Ray Scattering written by Julian Stangl and published by John Wiley & Sons. This book was released on 2013-09-10 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive overview of the possibilities and potential of X-ray scattering using nanofocused beams for probing matter at the nanoscale, including guidance on the design of nanobeam experiments. The monograph discusses various sources, including free electron lasers, synchrotron radiation and other portable and non-portable X-ray sources. For scientists using synchrotron radiation or students and scientists with a background in X-ray scattering methods in general.
