Download or read book Radiation Damage and Its Influence on Source Requirements for High Resolution X ray Holography written by and published by . This book was released on 1989 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soft x-ray holography offers the possibility of obtaining high resolution, 3-D images of living cells and organelles therein. To achieve a specified resolution, a certain number of photons must be scattered by the smallest features of interest within the sample. This requires a certain irradiating fluence, the magnitude of which depends on the wavelength of the x rays and the scattering cross- sections of the features. Unfortunately, irradiation of the sample will be accompanied by the absorption of x rays. If the dose is large, the sample will be damaged, possibly compromising the quality of the image. A theoretical study of the scattering and absorption of x rays during the creation of a hologram is described. Using a new prescription for scattering by condensed biological materials (e.g., protein and/or DNA) within the aqueous environment of a cell, we estimate the irradiating fluence required for a certain resolution and the associated sample dose. The relative merits of different x-ray wavelengths are discussed. A wavelength of about 44Å, just outside the water window'' (23.2--43.7Å), appears to be optimal in that the required fluence and dose are minimized, while reasonable x-ray penetrability is maintained. Estimates are given for the minimum source energy required and the maximum duration of an exposure to capture an image before blurring due heat induce motion. The use of colloidal gold tagging can enhance image contrast and reduce the required irradiating fluence and sample damage. 6 refs., 5 figs.
Download or read book X Ray Near Field Holography Beyond Idealized Assumptions of the Probe written by Johannes Hagemann and published by Göttingen University Press. This book was released on 2017 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: All images are flawed, no matter how good your lenses, mirrors etc. are. Especially in the hard X-ray regime it is challenging to manufacture high quality optics due to the weak interaction of multi-keV photons with matter. This is a tremendous challenge for obtaining high resolution quantitative X-ray microscopy images. In recent years lensless phase contrast imaging has become an alternative to classical absorptionbased imaging methods. Without any optics, the image is formed only by the free space propagation of the wave field. The actual image has to be formed posteriori by numerical reconstruction methods. Advanced phasing methods enable the experimentalist to recover a complex valued specimen from a single or a set of intensity measurement. This would be the ideal case - reality teaches us that there are no ideal imaging conditions. Describing, understanding and circumventing these non ideal imaging conditions and their effects on X-ray near-field holographic (NFH) imaging are the leitmotifs for this thesis. In NFH the non ideal conditions manifest themselves in the illuminating wave field or probe. The probe generally does not satisfy the canonical assumptions of fully coherent and monochromatic radiation emitted by a point source. The main results of this thesis are compiled as a collection of publications. An approach is shown to reconstruct the probe of a X-ray nano-focus setup by a series of measurements of the probe at varied Fresnel number. The following chapter presents a study concerning the reconstruction efficiency in terms of resolution for near- and far-field based lensless imaging. In the following, the reconstruction scheme for the probe is extended to incorporate the effects of partial coherence in the near field. This enables the recovery of the modal structure of the probe which yields a full description of its coherence properties. Giving up the assumption of temporal stability due to the stochastic pulses, delivered by X-ray free electron lasers, the reconstruction of probe and specimen must be achieved from a single shot. A suitable scheme for this purpose is proposed in this work.
Download or read book X ray Holography of Biological Specimens written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The author reviews the reasons for x-ray imaging of biological specimens and the techniques presently being used for x-ray microscopy. The author points out the advantages of x-ray holography and the difficulties of obtaining the requisite coherence with conventional sources. The author discusses the problems of radiation damage and the remarkable fact that short pulse x-ray sources circumvent these problems and obtain high-resolution images of specimens in the living state. Finally, the author reviews some of the efforts underway to develop high-intensity coherent x-ray sources for the laboratory. 14 references, 5 figures, 2 tables.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 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 X ray Microimaging for the Life Sciences written by and published by . This book was released on 1989 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Asia pacific Physics Conference Proceedings Of The Fifth Conference In 2 Volumes written by A C Chew and published by World Scientific. This book was released on 1994-04-19 with total page 1407 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1994-03 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Lensless Holography Methods for Soft X ray Resonant Coherent Imaging written by Diling Zhu and published by Stanford University. This book was released on 2010 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ability to interpret and inverse x-ray diffraction patterns from crystals has largely shaped our understanding of the structure of matter. However, structure determination of noncrystalline objects from their diffraction patterns is a much more difficult task. The dramatic increase in available coherent x-ray photon flux over the past decade has made possible a technique known as lensless coherent diffractive imaging (CDI), that addresses exactly this problem. The central question around CDI is the so-called phase problem: upon detection of the diffraction intensity, the phase information of the diffracted wave is inevitably lost. Generally, the phase problem is approached using iterative phase retrieval algorithms. Holographic methods, through interference with reference diffractions, encode the phase information directly inside the measured x-ray holograms, and are therefore able to avoid the stagnation and uniqueness problems commonly encountered by the iterative algorithms. This dissertation discusses two novel holographic methods for coherent lensless imaging using resonant soft x-rays. The first part focuses on generalizing the multiple-wavelength anomalous diffraction technique, a highly successful method for solving the crystal structures of biomacromolecules, into a multiple-wavelength holography technique for nanoscale resonant x-ray imaging. Using this method I show element specific reconstructions of nanoparticles and magnetization distribution in magnetic thin films with sub 50 nm resolution. The second part discusses progress in X-ray Fourier holography, an ultrafast lensless imaging platform that can be used with the upcoming x-ray free electron lasers. In particular, I will present experiments using two novel types of extended reference structures that bring the resolution beyond the precision of reference fabrication, previously regarded as the resolution limit for x-ray Fourier transform holography. Finally, future applications of holographic methods, especially experimental considerations for time-resolved studies of nanostructures using X-FELs, will be discussed.
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1990 with total page 1356 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book X Ray Lasers 1996 written by Sune Svanberg and published by CRC Press. This book was released on 1996-01-01 with total page 1162 pages. Available in PDF, EPUB and Kindle. Book excerpt: X-Ray Lasers 1996 provides not only an overview and progress report on this fast moving field, but also important reference material on which future work can be built. Topics covered include collisional x-ray lasers, table-top x-ray lasers, beam optics, x-ray optics, OFI and photo-pumped schemes, capillary schemes, international laser facilities, XUV nonlinear mixing, alternative soft x-ray sources, diagnostics, and applications. The volume is an essential addition to the libraries of researchers in the field.
Download or read book Modern Microscopies written by P.J. Duke and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: For several decades the electron microscope has been the instrument of choice for the examination of biological structures at high resolution. Biologists have be come familiar with the techniques and pitfalls of sample preparation and with the interpretation of the images obtained. The purpose of this book is to introduce the biologist to a number of new imaging techniques that are now becoming avail able to supplement and even extend the information that can be obtained from the now-traditional electron microscope. Some of these techniques are still at the experimental stage, while others, such as cryoelectron microscopy and confocal optical microscopy, are at advanced stages of development and are already avail able commercially. This book represents a first attempt to quantify the progress made by bring ing together, in one volume, an account of the technical bases and the future potentials of the various techniques. Although the content is primarily aimed at biologists, microscopists in other fields should also find the information of interest and use. All the chapters are written by leading experts who are at the forefront of these exciting developments. About half the book is concerned with x-ray microscopy; the editors make no apology for this since they are both intimately involved with developments associated with this field and therefore view it, perhaps with bias, as being of the utmost importance.
Download or read book X Ray Microscopy III written by Alan G. Michette and published by Springer. This book was released on 2013-06-05 with total page 499 pages. Available in PDF, EPUB and Kindle. Book excerpt: The growth of interest and research activity in X -ray microscopy is reflected in the increasing size and scope of a related series of international conferences, the latest of which (XRM90) was held at King's College London (3-7 September 1990) with over 130 delegates. Previous conferences in Gottingen and Brookhaven resulted in books in the Springer Series in Optical Sciences, and this volume, the proceedings of XRM90, maintains this tradition. Because of the large number of papers their lengths were strictly limited and, while most papers can be directly identified with conference presentations, in a few cases those on similar topics by the same authors have been combined into a longer paper to allow better use of the space. The book is divided into six parts, with Parts IT-VI covering the major areas of interest at the conference. In Part 1 are two overviews; Ron Burge presented the opening paper of the conference, while the closing, summary, contrlbution by Janos Kirz is included here as a comprehensive introduction to the remainder of the book. Part IT covers developments in X -ray sources and optics. The high average brightnesses of synchrotron radiation sources have made many applications pos sible, while the more convenient, laboratory-based, plasma sources offer much promise for the future. Several contributions report significant advances in X-ray optics, which must clearly continue fully to exploit the latest sources.
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 Measurements for the safe use of radiation written by Sherman P. Fivozinsky and published by . This book was released on 1976 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1973 with total page 670 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Exploratory Research and Development written by Lawrence Livermore National Laboratory and published by . This book was released on 1990 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:
