WorldWideScience

Sample records for backscattered electron imaging

  1. The complementary use of electron backscatter diffraction and ion channelling imaging for the characterization of nanotwins

    DEFF Research Database (Denmark)

    Alimadadi, Hossein; da Silva Fanta, Alice Bastos; Pantleon, Karen

    2013-01-01

    On the example of electrodeposited nickel films, it is shown that unique information on twins with dimensions on the nanoscale can be obtained by suitable combination of ion channelling imaging and electron backscatter diffraction analysis, whereas both (routine) single techniques cannot meet...

  2. An open-source engine for the processing of electron backscatter patterns: EBSD-image.

    Science.gov (United States)

    Pinard, Philippe T; Lagacé, Marin; Hovington, Pierre; Thibault, Denis; Gauvin, Raynald

    2011-06-01

    An open source software package dedicated to processing stored electron backscatter patterns is presented. The package gives users full control over the type and order of operations that are performed on electron backscatter diffraction (EBSD) patterns as well as the results obtained. The current version of EBSD-Image (www.ebsd-image.org) offers a flexible and structured interface to calculate various quality metrics over large datasets. It includes unique features such as practical file formats for storing diffraction patterns and analysis results, stitching of mappings with automatic reorganization of their diffraction patterns, and routines for processing data on a distributed computer grid. Implementations of the algorithms used in the software are described and benchmarked using simulated diffraction patterns. Using those simulated EBSD patterns, the detection of Kikuchi bands in EBSD-Image was found to be comparable to commercially available EBSD systems. In addition, 24 quality metrics were evaluated based on the ability to assess the level of deformation in two samples (copper and iron) deformed using 220 grit SiC grinding paper. Fourteen metrics were able to properly measure the deformation gradient of the samples.

  3. THERMAL NEUTRON BACKSCATTER IMAGING.

    Energy Technology Data Exchange (ETDEWEB)

    VANIER,P.; FORMAN,L.; HUNTER,S.; HARRIS,E.; SMITH,G.

    2004-10-16

    Objects of various shapes, with some appreciable hydrogen content, were exposed to fast neutrons from a pulsed D-T generator, resulting in a partially-moderated spectrum of backscattered neutrons. The thermal component of the backscatter was used to form images of the objects by means of a coded aperture thermal neutron imaging system. Timing signals from the neutron generator were used to gate the detection system so as to record only events consistent with thermal neutrons traveling the distance between the target and the detector. It was shown that this time-of-flight method provided a significant improvement in image contrast compared to counting all events detected by the position-sensitive {sup 3}He proportional chamber used in the imager. The technique may have application in the detection and shape-determination of land mines, particularly non-metallic types.

  4. Characterization of gold nanoparticle films: Rutherford backscattering spectroscopy, scanning electron microscopy with image analysis, and atomic force microscopy

    Directory of Open Access Journals (Sweden)

    Pia C. Lansåker

    2014-10-01

    Full Text Available Gold nanoparticle films are of interest in several branches of science and technology, and accurate sample characterization is needed but technically demanding. We prepared such films by DC magnetron sputtering and recorded their mass thickness by Rutherford backscattering spectroscopy. The geometric thickness dg—from the substrate to the tops of the nanoparticles—was obtained by scanning electron microscopy (SEM combined with image analysis as well as by atomic force microscopy (AFM. The various techniques yielded an internally consistent characterization of the films. In particular, very similar results for dg were obtained by SEM with image analysis and by AFM.

  5. Backscattered electron SEM imaging of resin sections from plant specimens: observation of histological to subcellular structure and CLEM.

    Science.gov (United States)

    Rizzo, N W; Duncan, K E; Bourett, T M; Howard, R J

    2016-08-01

    We have refined methods for biological specimen preparation and low-voltage backscattered electron imaging in the scanning electron microscope that allow for observation at continuous magnifications of ca. 130-70 000 X, and documentation of tissue and subcellular ultrastructure detail. The technique, based upon early work by Ogura & Hasegawa (1980), affords use of significantly larger sections from fixed and resin-embedded specimens than is possible with transmission electron microscopy while providing similar data. After microtomy, the sections, typically ca. 750 nm thick, were dried onto the surface of glass or silicon wafer and stained with heavy metals-the use of grids avoided. The glass/wafer support was then mounted onto standard scanning electron microscopy sample stubs, carbon-coated and imaged directly at an accelerating voltage of 5 kV, using either a yttrium aluminum garnet or ExB backscattered electron detector. Alternatively, the sections could be viewed first by light microscopy, for example to document signal from a fluorescent protein, and then by scanning electron microscopy to provide correlative light/electron microscope (CLEM) data. These methods provide unobstructed access to ultrastructure in the spatial context of a section ca. 7 × 10 mm in size, significantly larger than the typical 0.2 × 0.3 mm section used for conventional transmission electron microscopy imaging. Application of this approach was especially useful when the biology of interest was rare or difficult to find, e.g. a particular cell type, developmental stage, large organ, the interface between cells of interacting organisms, when contextual information within a large tissue was obligatory, or combinations of these factors. In addition, the methods were easily adapted for immunolocalizations. PMID:26708578

  6. 3D Backscatter Imaging System

    Science.gov (United States)

    Turner, D. Clark (Inventor); Whitaker, Ross (Inventor)

    2016-01-01

    Systems and methods for imaging an object using backscattered radiation are described. The imaging system comprises both a radiation source for irradiating an object that is rotationally movable about the object, and a detector for detecting backscattered radiation from the object that can be disposed on substantially the same side of the object as the source and which can be rotationally movable about the object. The detector can be separated into multiple detector segments with each segment having a single line of sight projection through the object and so detects radiation along that line of sight. Thus, each detector segment can isolate the desired component of the backscattered radiation. By moving independently of each other about the object, the source and detector can collect multiple images of the object at different angles of rotation and generate a three dimensional reconstruction of the object. Other embodiments are described.

  7. X-ray backscatter imaging

    Science.gov (United States)

    Dinca, Dan-Cristian; Schubert, Jeffrey R.; Callerame, J.

    2008-04-01

    In contrast to transmission X-ray imaging systems where inspected objects must pass between source and detector, Compton backscatter imaging allows both the illuminating source as well as the X-ray detector to be on the same side of the target object, enabling the inspection to occur rapidly and in a wide variety of space-constrained situations. A Compton backscatter image is similar to a photograph of the contents of a closed container, taken through the container walls, and highlights low atomic number materials such as explosives, drugs, and alcohol, which appear as especially bright objects by virtue of their scattering characteristics. Techniques for producing X-ray images based on Compton scattering will be discussed, along with examples of how these systems are used for both novel security applications and for the detection of contraband materials at ports and borders. Differences between transmission and backscatter images will also be highlighted. In addition, tradeoffs between Compton backscatter image quality and scan speed, effective penetration, and X-ray source specifications will be discussed.

  8. Staining plastic blocks with triiodide to image cells and soft tissues in backscattered electron SEM of skeletal and dental tissues.

    Science.gov (United States)

    Boyde, A

    2012-01-01

    Backscattered electron scanning electron microscopy (BSE SEM) is an invaluable method for studying the histology of the hard, mineralised components of poly-methyl methacrylate (PMMA) or other resin embedded skeletal and dental tissues. Intact tissues are studied in micro-milled or polished block faces with an electron-optical section thickness of the order of a half to one micron and with the area of the section as big as a whole--large or small--bone organ. However, BSE SEM does not give information concerning the distribution of uncalcified, 'soft', cellular and extracellular matrix components. This can be obtained by confocal microscopy of the same block and the two sorts of images merged but the blocks have to be studied in two microscope systems. The present work shows a new, simple and economic approach to visualising both components by using the triiodide ion in Lugol's iodine solution to stain the block surface prior to the application of any conductive coating--and the latter can be omitted if charging is suppressed by use of poor vacuum conditions in the SEM sample chamber. The method permits the use of archival tissue, and it will be valuable in studies of both normal growth and development and pathological changes in bones and joints, including osteoporosis and osteoarthritis, and tissue adaptation to implants. PMID:22828992

  9. Monte-Carlo simulation of backscattered electrons in Auger electron spectroscopy. Part 1: Backscattering factor calculation

    Energy Technology Data Exchange (ETDEWEB)

    Tholomier, M.; Vicario, E.; Doghmane, N.

    1987-10-01

    The contribution of backscattered electrons to Auger electrons yield was studied with a multiple scattering Monte-Carlo simulation. The Auger backscattering factor has been calculated in the 5 keV-60 keV energy range. The dependence of the Auger backscattering factor on the primary energy and the beam incidence angle were determined. Spatial distributions of backscattered electrons and Auger electrons are presented for a point incident beam. Correlations between these distributions are briefly investigated.

  10. A pseudo-3D approach based on electron backscatter diffraction and backscatter electron imaging to study the character of phase boundaries between Mg and long period stacking ordered phase in a Mg–2Y–Zn alloy

    Energy Technology Data Exchange (ETDEWEB)

    Afshar, Mehran, E-mail: m.afshar@mpie.de; Zaefferer, Stefan, E-mail: s.zaefferer@mpie.de

    2015-03-15

    In Mg–2 at.% Y–1 at.% Zn alloys, the LPSO (Long Period Stacking Ordered) phase is important to improve mechanical properties of the material. The aim of this paper is to present a study on the phase boundary character in these two-phase alloys. Using EBSD pattern analysis it was found that the 24R structure is the dominant LPSO phase structure in the current alloy. The phase boundary character between the Mg matrix and the LPSO phase was investigated using an improved pseudo-3D EBSD (electron backscatter diffraction) technique in combination with BSE or SE (backscatter or secondary electron) imaging. A large amount of very low-angle phase boundaries was detected. The (0 0 0 2) plane in the Mg matrix which is parallel to the (0 0 0 24) plane in the LPSO phase was found to be the most frequent plane for these phase boundaries. This plane is supposed to be the habit plane of the eutectic co-solidification of the Mg matrix and the LPSO phase. - Highlights: • It is shown that for the investigated alloy the LPSO phase has mainly 24R crystal structure. • A new method is presented which allows accurate determination of the 5-parameter grain or phase boundary character. • It is found that the low-angle phase boundaries appearing in the alloy all have basal phase boundary planes.

  11. Harvesting backscatter electrons for radiation therapy

    International Nuclear Information System (INIS)

    Purpose: An innovative technique is used to harvest backscatter electrons for the treatment of superficial small lesions of skin, oral cavity, and rectum where a significant dose gradient and maximum surface dose is desired. Methods and Materials: Backscatter electrons are harvested out of the primary electron beams from the linear accelerators. The design consists of a short cylindrical cone that fits snugly over a long cylindrical electron cone. The short cylindrical cone has a thick circular plate of high atomic number medium (Pb) attached to the distal end, and a lateral slit of variable length and width. The width of the slit could be closed as desired by rotating the two cones and the length can be increased by lowering the short cylindrical cone. Primary electrons strike the Pb plate perpendicularly and produce backscatter electrons that pass through the lateral slit for treatment. Using film and a parallel plate ion chamber, backscattered electron dose characteristics are studied. Results: The depth dose characteristic of the backscatter electron is very similar to that of the 0.2 mm Al half-value layer x-ray beam that is commonly used for the intracavitary and superficial lesions. The backscatter electron energy is nearly constant and effectively ≤ 1 MeV from the clinical megavoltage beams. The backscatter electron dose rate of 0.32-0.8 Gy/min could be achieved from modern accelerators without any modification. The beam flatness is dependent on the slit size and the depth of treatment, but is satisfactory to treat small lesions. Conclusions: The measured data for backscatter electron energy, fluence, depth dose, flatness, dose rate, and absolute dose indicates that the harvested backscattered electrons are suitable for clinical use

  12. Backscattered electron imaging: The role in calcified tissue and implant analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bloebaum, R.D.; Bachus, K.N.; Boyce, T.M. (Department of Veterans Affairs Medical Center (151F), Salt Lake City, UT (USA))

    1990-07-01

    The working distance and tilt studies helped to clarify the influences of specimen variability when the BSE mode is used in calcified tissue research. This work has shown that the BSEPs of cortical bone may be accurately maintained within 2 percent error over a 10 degree range of tilt, or 300 microns working distance variation. If future bone and implant investigators wish to conduct accurate, quantitative mineral microanalysis in bone, then standard grinding and polishing techniques should be adequate if calibration procedures are developed. The BSEP characteristics of the pure metals make them suitable to be used for calibrating the BSE signal. BSE analysis, with correlated biomechanical studies, will lead us to a better understanding of the relationships between structure, function, and mineral content in bone. On-line BSEP analysis techniques will expand our understanding of the mineralization events in bone which are associated with aging, weightlessness, pharmaceutical therapies, and the presence of biomaterials. The future of the BSE imaging technology and the contributions to be made in understanding the histometry, biomechanics and mineral content of bone as well as bone's response to implant materials has just begun to unfold. 74 references.

  13. Electron backscatter diffraction in materials characterization

    Directory of Open Access Journals (Sweden)

    Dejan Stojakovic

    2012-03-01

    Full Text Available Electron Back-Scatter Diffraction (EBSD is a powerful technique that captures electron diffraction patterns from crystals, constituents of material. Captured patterns can then be used to determine grain morphology, crystallographic orientation and chemistry of present phases, which provide complete characterization of microstructure and strong correlation to both properties and performance of materials. Key milestones related to technological developments of EBSD technique have been outlined along with possible applications using modern EBSD system. Principles of crystal diffraction with description of crystallographic orientation, orientation determination and phase identification have been described. Image quality, resolution and speed, and system calibration have also been discussed. Sample preparation methods were reviewed and EBSD application in conjunction with other characterization techniques on a variety of materials has been presented for several case studies. In summary, an outlook for EBSD technique was provided.

  14. Demonstration of differential backscatter absorption gas imaging

    International Nuclear Information System (INIS)

    Backscatter absorption gas imaging (BAGI) is a technique that uses infrared active imaging to generate real-time video imagery of gas plumes. We describe a method that employs imaging at two wavelengths (absorbed and not absorbed by the gas to be detected) to allow wavelength-differential BAGI. From the frames collected at each wavelength, an absorbance image is created that displays the differential absorbance of the atmosphere between the imager and the backscatter surface. This is analogous to a two-dimensional topographic differential absorption lidar or differential optical absorption spectroscopy measurement. Gas plumes are displayed, but the topographic scene image is removed. This allows a more effective display of the plume image, thus ensuring detection under a wide variety of conditions. The instrument used to generate differential BAGI is described. Data generated by the instrument are presented and analyzed to estimate sensitivity. (c) 2000 Optical Society of America

  15. Present State of Electron Backscatter Diffraction and Prospective Developments

    Energy Technology Data Exchange (ETDEWEB)

    Schwarzer, R A; Field, D P; Adams, B L; Kumar, M; Schwartz, A J

    2008-10-24

    Electron backscatter diffraction (EBSD), when employed as an additional characterization technique to a scanning electron microscope (SEM), enables individual grain orientations, local texture, point-to-point orientation correlations, and phase identification and distributions to be determined routinely on the surfaces of bulk polycrystals. The application has experienced rapid acceptance in metallurgical, materials, and geophysical laboratories within the past decade (Schwartz et al. 2000) due to the wide availability of SEMs, the ease of sample preparation from the bulk, the high speed of data acquisition, and the access to complementary information about the microstructure on a submicron scale. From the same specimen area, surface structure and morphology of the microstructure are characterized in great detail by the relief and orientation contrast in secondary and backscatter electron images, element distributions are accessed by energy dispersive spectroscopy (EDS), wavelength dispersive spectroscopy (WDS), or cathodoluminescence analysis, and the orientations of single grains and phases can now be determined, as a complement, by EBSD.

  16. Structure and mineralisation density of antler and pedicle bone in red deer (Cervus elaphus L.) exposed to different levels of environmental fluoride: a quantitative backscattered electron imaging study

    Science.gov (United States)

    KIERDORF, UWE; KIERDORF, HORST; BOYDE, ALAN

    2000-01-01

    The structure and relative degree of mineralisation of antler and pedicle bone of yearling red deer stags exposed either to low or high levels of environmental fluoride were determined by digital quantitative backscattered electron (BSE) imaging. Bone fluoride content (BFC) in antlers (845±86 mg F−/kg ash, arithmetic mean± S.E.M.) and pedicles (1448±154 mg F−/kg ash) of deer from a highly fluoride polluted area in North Bohemia (Czech Republic) were significantly higher (P fluoride induced disturbance of bone mineralisation. The rapid growth of antlers leads both to a high mineral demand and a high rate of fluoride uptake during antlerogenesis. This, and the limited lifespan of antlers, which does not allow for a compensation of a delay in the onset or progression of the mineralisation process, renders antler bone particularly susceptible to fluoride. Antlers are therefore considered a useful model for studying fluoride effects on bone formation. Furthermore, analysis of cast antlers enables a noninvasive monitoring of environmental pollution by fluorides. PMID:10697290

  17. Simulation of ultrasound backscatter images from fish

    DEFF Research Database (Denmark)

    Pham, An Hoai; Stage, Bjarne; Hemmsen, Martin Christian;

    2011-01-01

    , a cod (Gadus morhua) was scanned with both a BK Medical ProFocus 2202 ultrasound scanner and a Toshiba Aquilion ONE computed tomography (CT) scanner. The US images of the fis were compared with US images created using the ultrasound simulation program Field II. The center frequency of the transducer...... is 10 MHz and the Full Width at Half Maximum (FWHM) at the focus point is 0.54 mm in the lateral direction. The transducer model in Field II was calibrated using a wire phantom to validate the simulated point spread function. The inputs to the simulation were the CT image data of the fis converted...... to simulated scatter maps. The positions of the point scatterers were assumed to be uniformly distributed. The scatter amplitudes were generated with a new method based on the segmented CT data in Hounsfiel Units and backscatter data for the different types of tissues from the literature. The simulated US...

  18. Electron energy loss and diffraction of backscattered electrons from silicon

    Science.gov (United States)

    Winkelmann, Aimo; Aizel, Koceila; Vos, Maarten

    2010-05-01

    Electrons backscattered from crystals can show Kikuchi patterns: variations in intensity for different outgoing directions due to diffraction by the lattice. Here, we measure these effects as a function of their energy loss for 30 keV electrons backscattered from silicon. The change in diffraction contrast with energy loss depends strongly on the scattering geometry. At steep incidence on the sample, diffraction contrast in the observed Kikuchi bands decreases rapidly with energy loss. For an energy loss larger than about 150 eV the contrast is more than 5 times less than the contrast due to electrons near zero energy loss. However, for grazing incidence angles, maximum Kikuchi band contrast is observed for electrons with an energy loss near 60 eV, where the contrast is more than 2.5× larger than near zero energy loss. In addition, in this grazing incidence geometry, the Kikuchi diffraction effects stay significant even for electrons that have lost hundreds of electron volts. For the maximum measured energy loss of 440 eV, the electrons still show a contrast that is 1.5 × larger than that of the electrons near zero energy loss. These geometry-dependent observations of Kikuchi band diffraction contrast are interpreted based on the elastic and inelastic scattering properties of electrons and dynamical diffraction simulations.

  19. Effects of Odanacatib on bone mineralization density distribution in thoracic spine and femora of ovariectomized adult rhesus monkeys: a quantitative backscattered electron imaging study.

    Science.gov (United States)

    Fratzl-Zelman, Nadja; Roschger, Paul; Fisher, John E; Duong, Le T; Klaushofer, Klaus

    2013-03-01

    Odanacatib (ODN) has been developed as a selective inhibitor of cathepsin K, the major cysteine protease in osteoclasts. In adult rhesus monkeys, treatment with ODN prevents ovariectomy-induced bone loss in lumbar vertebrae and hip. In this study, we evaluate the effects of ODN on bone mineralization density distribution (BMDD) by quantitative backscattered electron imaging in vertebral spongiosa, distal femoral metaphyseal and cortical shaft from monkeys (aged 16-23 years), treated with vehicle (n=5) or ODN (6 mg/kg, n=4 or 30 mg/kg, n=4, PO daily) for 21 months. Dual-energy X-ray absorptiometry was measured in a subset of distal femoral samples. In lumbar vertebrae there was a shift to higher mineralization in samples from ODN-treated groups, compared to vehicle: CaMean (+4%), CaPeak (+3%), CaWidth (-9%), CaLow (-28%) in the 6 mg/kg group and CaMean (+5.1%, p<0.023), CaPeak (+3.4%, p<0.046), CaWidth (-15.7%, p=0.06) and CaLow (-38.2%, p<0.034) in the 30 mg/kg group. In distal femoral metaphyseal cancellous bone, there was a clear tendency toward a dose-dependent increase in matrix mineralization, as in the spine. However, primary and osteonal bone of the distal cortical diaphyses showed no significant change in BMDD, whereas bone mineral density was significantly increased after treatment. In ovariectomized monkeys, this study shows that ODN treatment increased trabecular BMDD, consistent with its previously reported ability to reduce cancellous remodeling. Here, ODN also showed no changes in BMDD in cortical bone sites, consistent with its actions on maintaining endocortical and stimulating periosteal bone formation. PMID:23179105

  20. Working at higher magnifications in scanning electron microscopy with secondary and backscattered electrons on metal coated biological specimens and imaging macromolecular cell membrane structures.

    Science.gov (United States)

    Peters, K R

    1985-01-01

    Membrane structures of macromolecular dimensions were imaged with high resolution secondary electron type I (SE-I) signal contrasts on metal coated biological specimens. The quality of the surface information was strongly dependent on the signal used for microscopy and on the properties of metal films, i.e., thickness, continuity, structure and decoration effects. Films of 10 nm thickness produced so much type II electrons that identical images were obtained with the conventional SE-II and BSE-II signals. In such images, the type I SE signal was so low that only very weak contrasts were recognizable. If the films--continuous or discontinuous--were composed of large metal aggregates (gold and platinum) a strong micro-roughness contrast was produced by the type II signal. At high magnifications (100,000 x) this background signal greatly reduced the S/N ratio of the SE-I signal. A similar effect was previously shown to be produced by the type III background signal. The type II background signal minimized when continuous films of small aggregates (tantalum and chromium) were applied. SE-I contrast dominated in the image if the film thickness was limited to 1 nm. Additionally, it was found that gold and platinum decorated membrane surface structures, less than 20 nm in size, and did not reveal all the topographic information available (size, shape, orientation spacing of small surface features) but merely displayed center-to-center distances. These decoration effects were avoided and extensive topographic information was obtained through surface coating with Ta or Cr. PMID:4095499

  1. Characterization of a γ-backscattering imaging device

    Science.gov (United States)

    González, N.; Fajardo, E.; Blanco, W.; Cristancho, F.

    2012-02-01

    The Compton Camera is a γ-backscattering imaging device that allows us to obtain images of hidden objects. In order to evaluate the factors that affect the quality of those images, experiments were carried out to determine its response to different materials. Mathematical methods have been developed to quantify the image quality.

  2. A backscattered x-ray imager for medical applications

    Science.gov (United States)

    Morris, Eric Jude L.; Dibianca, Frank A.; Shukla, Hemant; Gulabani, Daya

    2005-04-01

    Conventional X-ray radiographic systems rely on transmitted photons for the production of images. Backscatter imaging makes use of the more abundant scattered photons for image formation. Specifically, incoherently (Compton) scattered X-ray photons are detected and used for image formation in this modality of medical imaging. However, additional information is obtained when the transmitted X-ray photons are also detected and used. Transmission radiography produces a two-dimensional image of a three dimensional system, therefore image information from a shallower object is often contaminated by image information from underlying objects. Backscattered x-ray imaging largely overcomes this deficiency by imaging depth selectively, which reduces corruption of shallow imaging information by information from deeper objects lying under it. Backscattered x-ray imaging may be particularly useful for examining anatomical structures at shallow depths beneath the skin. Some typical applications for such imaging might be breast imaging, middle ear imaging, imaging of skin melanomas, etc. Previous investigations, by way of theoretical calculations and computational simulations into the feasibility of this kind of imaging have uncovered high-contrast and SNR parameters. Simulations indicate that this method can be used for imaging relatively high-density objects at depths of up to approximately five centimeters below the surface. This paper presents both theoretical and experimental SNR results on this new medical imaging modality.

  3. Profiling of back-scattered electrons in opposed magnetic field of a Twin Electron Beam Gun

    International Nuclear Information System (INIS)

    Electron gun is extensively used in material processing, physical vapour deposition and atomic vapour based laser processes. In these processes where the electron beam is incident on the substrate, a significant fraction of electron beam gets back-scattered from the target surface. The trajectory of this back scattered electron beam depends on the magnetic field in the vicinity. The fraction of back-scattered depends on the atomic number of the target metal and can be as high as ∼40% of the incident beam current. These back-scattered electrons can cause undesired hot spots and also affect the overall process. Hence, the study of the trajectory of these back-scattered electrons is important. This paper provides the details of experimentally mapped back-scattered electrons of a 2×20kW Twin Electron Beam Gun (TEBG) in opposed magnetic field i.e. with these guns placed at 180° to each other.

  4. Formation of Nanoporous Gold Studied by Transmission Electron Backscatter Diffraction

    NARCIS (Netherlands)

    de Jeer, Leo T. H.; Gomes, Diego Ribas; Nijholt, Jorrit E.; van Bremen, Rik; Ocelik, Vaclav; De Hosson, Jeff Th. M.

    2015-01-01

    Transmission electron backscatter diffraction (t-EBSD) was used to investigate the effect of dealloying on the microstructure of 140-nm thin gold foils. Statistical and local comparisons of the microstructure between the nonetched and nanoporous gold foils were made. Analyses of crystallographic tex

  5. Analysis of a proposed Compton backscatter imaging technique

    Science.gov (United States)

    Hall, James M.; Jacoby, Barry A.

    1994-03-01

    One-sided imaging techniques are currently being used in nondestructive evaluation of surfaces and shallow subsurface structures. In this work we present both analytical calculations and detailed Monte Carlo simulations aimed at assessing the capability of a proposed Compton backscattering imaging technique designed to detect and characterize voids located several centimeters below the surface of a solid.

  6. Pattern matching approach to pseudosymmetry problems in electron backscatter diffraction.

    Science.gov (United States)

    Nolze, Gert; Winkelmann, Aimo; Boyle, Alan P

    2016-01-01

    We demonstrate an approach to overcome Kikuchi pattern misindexing problems caused by crystallographic pseudosymmetry in electron backscatter diffraction (EBSD) measurements. Based on the quantitative comparison of experimentally measured Kikuchi patterns with dynamical electron diffraction simulations, the algorithm identifies the best-fit orientation from a set of pseudosymmetric candidates. Using measurements on framboidal pyrite (FeS2) as an example, we also show the improvement of the orientation precision using this approach.

  7. X-ray backscatter imaging for radiography by selective detection and snapshot: Evolution, development, and optimization

    Science.gov (United States)

    Shedlock, Daniel

    Compton backscatter imaging (CBI) is a single-sided imaging technique that uses the penetrating power of radiation and unique interaction properties of radiation with matter to image subsurface features. CBI has a variety of applications that include non-destructive interrogation, medical imaging, security and military applications. Radiography by selective detection (RSD), lateral migration radiography (LMR) and shadow aperture backscatter radiography (SABR) are different CBI techniques that are being optimized and developed. Radiography by selective detection (RSD) is a pencil beam Compton backscatter imaging technique that falls between highly collimated and uncollimated techniques. Radiography by selective detection uses a combination of single- and multiple-scatter photons from a projected area below a collimation plane to generate an image. As a result, the image has a combination of first- and multiple-scatter components. RSD techniques offer greater subsurface resolution than uncollimated techniques, at speeds at least an order of magnitude faster than highly collimated techniques. RSD scanning systems have evolved from a prototype into near market-ready scanning devices for use in a variety of single-sided imaging applications. The design has changed to incorporate state-of-the-art detectors and electronics optimized for backscatter imaging with an emphasis on versatility, efficiency and speed. The RSD system has become more stable, about 4 times faster, and 60% lighter while maintaining or improving image quality and contrast over the past 3 years. A new snapshot backscatter radiography (SBR) CBI technique, shadow aperture backscatter radiography (SABR), has been developed from concept and proof-of-principle to a functional laboratory prototype. SABR radiography uses digital detection media and shaded aperture configurations to generate near-surface Compton backscatter images without scanning, similar to how transmission radiographs are taken. Finally, a

  8. Phase Identification of Dual-Phase (DP980) Steels by Electron Backscatter Diffraction and Nanoindentation Techniques.

    Science.gov (United States)

    Zhang, Fan; Ruimi, Annie; Field, David P

    2016-02-01

    Phase identification of multi-phase materials provides essential information relating the material to its mechanical properties. In this study we selected DP980, a type of dual-phase steel, to investigate the content of martensite and ferrite grains. A combination of advanced techniques was used to provide detailed and precise information of the microstructure. Scanning and transmission electron microscopy were used to provide observations of the sample surface at different scales. Martensite and ferrite phases of DP980 were further identified and characterized using electron backscatter diffraction and scanning probe microscopy. Results obtained with nanoindentation tests confirmed that the differences in nanohardness values in single-phase grains are martensite and ferrite with different surface heights shown by scanning probe microscopy. The similarity shown in the image quality map and scanning probe microscopy proves that a large fraction of martensite can be distinguished in this undeformed material using image quality parameters obtained during electron backscatter diffraction imaging. PMID:26781200

  9. Electron backscatter diffraction of a plutonium-gallium alloy

    Science.gov (United States)

    Boehlert, C. J.; Zocco, T. G.; Schulze, R. K.; Mitchell, J. N.; Pereyra, R. A.

    2003-01-01

    An experimental technique has recently been developed to characterize reactive metals, including plutonium (Pu) and cerium, using electron backscatter diffraction (EBSD). Microstructural characterization of Pu and its alloys by EBSD had been previously elusive primarily because of the extreme toxicity and rapid surface oxidation rate associated with Pu metal. The experimental technique, which included ion-sputtering the metal surface using a scanning Auger microprobe (SAM) followed by vacuum transfer of the sample from the SAM to the scanning electron microscope (SEM), used to obtain electron backscatter diffraction Kikuchi patterns and orientation maps for a Pu-gallium alloy is described and the initial microstructural observations based on the analysis are discussed. The phase transformation behavior between the δ (face-centered cubic) and ɛ (body-centered-cubic) structures is explained by combining the SEM and EBSD observations.

  10. Detection and imaging in strongly backscattering randomly layered media

    International Nuclear Information System (INIS)

    Echoes from small reflectors buried in the heavy clutter are weak and difficult to distinguish from the medium backscatter. Detection and imaging with sensor arrays in such media require filtering out the unwanted backscatter and enhancing the echoes from the reflectors that we wish to locate. We consider a filtering and detection approach based on the singular value decomposition of the local cosine transform of the array response matrix. The algorithm is general and can be used for detection and imaging in the heavy clutter, but its analysis depends on the model of the cluttered medium. This paper is concerned with the analysis of the algorithm in finely layered random media. We obtain a detailed characterization of the singular values of the transformed array response matrix and justify the systematic approach of the filtering algorithm for detecting and refining the time windows that contain the echoes that are useful in imaging

  11. Reproducible methods for calibrating the backscattered electron signal for quantitative assessment of mineral content in bone

    Energy Technology Data Exchange (ETDEWEB)

    Boyce, T.M.; Bloebaum, R.D.; Bachus, K.N.; Skedros, J.G. (VA Medical Center, Salt Lake City, UT (USA))

    1990-09-01

    Backscattered electron (BSE) imaging shows promise for orthopaedic and bone research. BSE images of bone may be captured on-line directly from the scanning electron microscope (SEM), and then analyzed to produce a backscattered electron profile (BSEP), a modified image graylevel histogram which is representative of the mineral content in bone. The goals of this work were (1) develop a reproducible graylevel calibration technique for bone specimens, and (2) determine a conservative time interval during which SEM operating conditions would remain stable. Calibration standards containing pure aluminum and pure magnesium wires were placed in the SEM with human cancellous bone. Baseline imaging conditions were first established by adjusting the SEM until the bone image displayed good resolution and graylevel separation between regions of different mineral content. Microscope brightness and contrast controls were randomly changed to initiate the new operating conditions of another imaging session, and graylevel values from the calibration metals were used to readjust the microscope back to baseline operating conditions. Weighted mean graylevel values of the BSEPs from calibration trials were compared to those of the baseline. Data showed that bone images could be reproduced within 1.2 percent. It was also concluded that our equipment required calibration checks at 20 minute intervals.

  12. Many-beam dynamical simulation of electron backscatter diffraction patterns

    Energy Technology Data Exchange (ETDEWEB)

    Winkelmann, Aimo [Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, D-06120 Halle (Germany)], E-mail: winkelm@mpi-halle.mpg.de; Trager-Cowan, Carol; Sweeney, Francis [Department of Physics, University of Strathclyde, Glasgow G4 ONG, Scotland (United Kingdom); Day, Austin P. [Aunt Daisy Scientific Ltd., Dixton Rd., Monmouth, Gwent, NP25 3PP (United Kingdom); Parbrook, Peter [EPSRC National Centre for III-V Technologies, University of Sheffield (United Kingdom)

    2007-04-15

    We present an approach for the simulation of complete electron backscatter diffraction (EBSD) patterns where the relative intensity distributions in the patterns are accurately reproduced. The Bloch wave theory is applied to describe the electron diffraction process. For the simulation of experimental patterns with a large field of view, a large number of reflecting planes has to be taken into account. This is made possible by the Bethe perturbation of weak reflections. Very good agreement is obtained for simulated and experimental patterns of gallium nitride GaN{l_brace}0001{r_brace} at 20 kV electron energy. Experimental features like zone-axis fine structure and higher-order Laue zone rings are accurately reproduced. We discuss the influence of the diffraction of the incident beam in our experiment.

  13. Many-beam dynamical simulation of electron backscatter diffraction patterns.

    Science.gov (United States)

    Winkelmann, Aimo; Trager-Cowan, Carol; Sweeney, Francis; Day, Austin P; Parbrook, Peter

    2007-01-01

    We present an approach for the simulation of complete electron backscatter diffraction (EBSD) patterns where the relative intensity distributions in the patterns are accurately reproduced. The Bloch wave theory is applied to describe the electron diffraction process. For the simulation of experimental patterns with a large field of view, a large number of reflecting planes has to be taken into account. This is made possible by the Bethe perturbation of weak reflections. Very good agreement is obtained for simulated and experimental patterns of gallium nitride GaN{0001} at 20kV electron energy. Experimental features like zone-axis fine structure and higher-order Laue zone rings are accurately reproduced. We discuss the influence of the diffraction of the incident beam in our experiment. PMID:17126489

  14. Applications of the electron backscatter diffraction technique to ceramic materials

    Science.gov (United States)

    Koblischka, M. R.; Koblischka-Veneva, A.

    2013-07-01

    A technique with a relatively high spatial resolution is required for an effective analysis of the microstructure of ceramic materials. The recently developed electron backscatter diffraction (EBSD) technique, which works within a scanning electron microscope, enables a spatially highly resolved study of crystallographic orientations while recording Kikuchi patterns on a user-defined grid. However, such an EBSD texture analysis was until now not often performed on ceramic materials - in contrary, the technique is widely employed in the analysis of metallic materials, including the investigation of various types of steels. The use of ceramics possesses a variety of problems for EBSD investigations like: (i) complicated crystal structure, (ii) difficult surface preparation, and (iii) problems arising from a low conductivity of the ceramic materials. Here, we discuss these problems and present solutions in order to obtain high-quality Kikuchi patterns from such ceramics.

  15. Transport equation theory of electron backscattering and x-ray production

    International Nuclear Information System (INIS)

    A transport equation theory of electron backscattering and x ray production is derived and applied to energy dissipation of 30-KeV electrons for copper as a function of depth and to the energy distribution of backscattered electrons for copper, aluminum, and gold. These results are plotted and compared with experiment. Plots for variations of backscattering with atomic number and with angle of incidence, and polar plots of backscattering for 30-keV electrons at normal incidence are also presented. 10 references, seven figures

  16. Correcting for 3D distortion when using backscattered electron detectors in a scanning electron microscope.

    Science.gov (United States)

    Proctor, Jacob M

    2009-01-01

    A variable pressure scanning electron microscope (VPSEM) can produce a topographic surface relief of a physical object under examination, in addition to its two-dimensional (2D) image. This topographic surface relief is especially helpful when dealing with porous rock because it may elucidate the pore-space structure as well as grain shape and size. Whether the image accurately reproduces the physical object depends on the management of the hardware, acquisition, and postprocessing. Two problems become apparent during testing: (a) a topographic surface relief of a precision ball bearing is distorted and does not correspond to the physical dimensions of the actual sphere and (b) an image of a topographic surface relief of a Berea sandstone is geometrically tilted and topographically distorted even after standard corrections are applied. The procedure presented here is to ensure the veracity of the image, and includes: (a) adjusting the brightness and contrast levels originally provided by the manufacturer and (b) tuning the amplifiers of the backscatter detector plates to be equal to each other, and producing zero voltage when VPSEM is idle. This procedure is tested and verified on the said two physical samples. SCANNING 31: 59-64, 2009. (c) 2009 Wiley Periodicals, Inc.

  17. Crack nucleation using combined crystal plasticity modelling, high-resolution digital image correlation and high-resolution electron backscatter diffraction in a superalloy containing non-metallic inclusions under fatigue

    Science.gov (United States)

    Zhang, Tiantian; Jiang, Jun; Britton, Ben; Shollock, Barbara; Dunne, Fionn

    2016-05-01

    A crystal plasticity finite-element model, which explicitly and directly represents the complex microstructures of a non-metallic agglomerate inclusion within polycrystal nickel alloy, has been developed to study the mechanistic basis of fatigue crack nucleation. The methodology is to use the crystal plasticity model in conjunction with direct measurement at the microscale using high (angular) resolution-electron backscatter diffraction (HR-EBSD) and high (spatial) resolution-digital image correlation (HR-DIC) strain measurement techniques. Experimentally, this sample has been subjected to heat treatment leading to the establishment of residual (elastic) strains local to the agglomerate and subsequently loaded under conditions of low cyclic fatigue. The full thermal and mechanical loading history was reproduced within the model. HR-EBSD and HR-DIC elastic and total strain measurements demonstrate qualitative and quantitative agreement with crystal plasticity results. Crack nucleation by interfacial decohesion at the nickel matrix/agglomerate inclusion boundaries is observed experimentally, and systematic modelling studies enable the mechanistic basis of the nucleation to be established. A number of fatigue crack nucleation indicators are also assessed against the experimental results. Decohesion was found to be driven by interface tensile normal stress alone, and the interfacial strength was determined to be in the range of 1270-1480 MPa.

  18. Crack nucleation using combined crystal plasticity modelling, high-resolution digital image correlation and high-resolution electron backscatter diffraction in a superalloy containing non-metallic inclusions under fatigue

    Science.gov (United States)

    Zhang, Tiantian; Britton, Ben; Shollock, Barbara; Dunne, Fionn

    2016-01-01

    A crystal plasticity finite-element model, which explicitly and directly represents the complex microstructures of a non-metallic agglomerate inclusion within polycrystal nickel alloy, has been developed to study the mechanistic basis of fatigue crack nucleation. The methodology is to use the crystal plasticity model in conjunction with direct measurement at the microscale using high (angular) resolution-electron backscatter diffraction (HR-EBSD) and high (spatial) resolution-digital image correlation (HR-DIC) strain measurement techniques. Experimentally, this sample has been subjected to heat treatment leading to the establishment of residual (elastic) strains local to the agglomerate and subsequently loaded under conditions of low cyclic fatigue. The full thermal and mechanical loading history was reproduced within the model. HR-EBSD and HR-DIC elastic and total strain measurements demonstrate qualitative and quantitative agreement with crystal plasticity results. Crack nucleation by interfacial decohesion at the nickel matrix/agglomerate inclusion boundaries is observed experimentally, and systematic modelling studies enable the mechanistic basis of the nucleation to be established. A number of fatigue crack nucleation indicators are also assessed against the experimental results. Decohesion was found to be driven by interface tensile normal stress alone, and the interfacial strength was determined to be in the range of 1270–1480 MPa. PMID:27279765

  19. Energy Filtering and Coaxial Detection of the Backscattered Electrons in Scanning Electron Microscope

    Institute of Scientific and Technical Information of China (English)

    JIANG Chang-Zhong; P. Morin; N. Rosenberg

    2000-01-01

    A new detection system in scanning electron microscope, which filters in energy and detects the backscattered electrons close to the microscope axis, is described. This technique ameliorates the dependence of the back. scat tering coefficient on atomic number, and suppresses effectively the relief contrast at the same time. Therefore this new method is very suitable to the composition analysis.

  20. Principles of depth-resolved Kikuchi pattern simulation for electron backscatter diffraction.

    Science.gov (United States)

    Winkelmann, A

    2010-07-01

    This paper presents a tutorial discussion of the principles underlying the depth-dependent Kikuchi pattern formation of backscattered electrons in the scanning electron microscope. To illustrate the connections between various electron diffraction methods, the formation of Kikuchi bands in electron backscatter diffraction in the scanning electron microscope and in transmission electron microscopy are compared with the help of simulations employing the dynamical theory of electron diffraction. The close relationship between backscattered electron diffraction and convergent beam electron diffraction is illuminated by showing how both effects can be calculated within the same theoretical framework. The influence of the depth-dependence of diffuse electron scattering on the formation of the experimentally observed electron backscatter diffraction contrast and intensity is visualized by calculations of depth-resolved Kikuchi patterns. Comparison of an experimental electron backscatter diffraction pattern with simulations assuming several different depth distributions shows that the depth-distribution of backscattered electrons needs to be taken into account in quantitative descriptions. This should make it possible to obtain more quantitative depth-dependent information from experimental electron backscatter diffraction patterns via correlation with dynamical diffraction simulations and Monte Carlo models of electron scattering.

  1. Source point calibration from an arbitrary electron backscattering pattern

    DEFF Research Database (Denmark)

    Lassen, Niels Christian Krieger

    1999-01-01

    Precise knowledge of the position of the source point is a requirement if electron backscattering patterns (EBSPs) are to be used for crystal orientation measurements or other types of measurements which demand a geometrical analysis of the patterns. Today, possibly the most popular method...... for locating the source point is a computational technique which uses the positions of a number of indexed Kikuchi bands for calculating the coordinates of the point. A serious limitation of this calibration technique is, however, that the localized bands must first be indexed, which is difficult...... if the location of the source point is not known with reasonable precision. This paper describes a new technique which determines the location of the source point from the positions of a number of bands in an arbitrary EBSP. Besides the positions of the Kikuchi bands, the only information which is required...

  2. Electron backscatter diffraction: Strategies for reliable data acquisition and processing

    International Nuclear Information System (INIS)

    In electron backscatter diffraction (EBSD) software packages there are many user choices both in data acquisition and in data processing and display. In order to extract maximum scientific value from an inquiry, it is helpful to have some guidelines for best practice in conducting an EBSD investigation. The purpose of this article therefore is to address selected topics of EBSD practice, in a tutorial manner. The topics covered are a brief summary on the principles of EBSD, specimen preparation, calibration of an EBSD system, experiment design, speed of data acquisition, data clean-up, microstructure characterisation (including grain size) and grain boundary characterisation. This list is not meant to cover exhaustively all areas where EBSD is used, but rather to provide a resource consisting of some useful strategies for novice EBSD users.

  3. Monte Carlo simulations of landmine detection using neutron backscattering imaging

    Energy Technology Data Exchange (ETDEWEB)

    Datema, Cor P. E-mail: c.datema@iri.tudelft.nl; Bom, Victor R.; Eijk, Carel W.E. van

    2003-11-01

    Neutron backscattering is a technique that has successfully been applied to the detection of non-metallic landmines. Most of the effort in this field has concentrated on single detectors that are scanned across the soil. Here, two new approaches are presented in which a two-dimensional image of the hydrogen distribution in the soil is made. The first method uses an array of position-sensitive {sup 3}He-tubes that is placed in close proximity of the soil. The second method is based on coded aperture imaging. Here, thermal neutrons from the soil are projected onto a detector which is typically placed one to several meters above the soil. Both methods use a pulsed D/D neutron source. The Monte Carlo simulation package GEANT 4 was used to investigate the performance of both imaging systems.

  4. Towards high accuracy calibration of electron backscatter diffraction systems

    Energy Technology Data Exchange (ETDEWEB)

    Mingard, Ken [National Physical Laboratory, Hampton Road, Teddington, TW11 0LW (United Kingdom); Day, Austin, E-mail: Austin.Day@ADSci.co.uk [Aunt Daisy Scientific Ltd., Claremont House, Lydney, GL15 5DX (United Kingdom); Maurice, Claire [Ecole des Mines, Centre SMS-UMR CNRS 5146, 158 cours Fauriel, 42023 Saint Etienne Cedex 2 (France); Quested, Peter [National Physical Laboratory, Hampton Road, Teddington, TW11 0LW (United Kingdom)

    2011-04-15

    For precise orientation and strain measurements, advanced Electron Backscatter Diffraction (EBSD) techniques require both accurate calibration and reproducible measurement of the system geometry. In many cases the pattern centre (PC) needs to be determined to sub-pixel accuracy. The mechanical insertion/retraction, through the Scanning Electron Microscope (SEM) chamber wall, of the electron sensitive part of modern EBSD detectors also causes alignment and positioning problems and requires frequent monitoring of the PC. Optical alignment and lens distortion issues within the scintillator, lens and charge-coupled device (CCD) camera combination of an EBSD detector need accurate measurement for each individual EBSD system. This paper highlights and quantifies these issues and demonstrates the determination of the pattern centre using a novel shadow-casting technique with a precision of {approx}10 {mu}m or {approx}1/3 CCD pixel. -- Research highlights: {yields} Issues with accurate EBSD calibration are discussed. {yields} Optical distortion data for 17 EBSD detectors are tabulated. {yields} A new shadow-casting system is demonstrated; it gives a pattern centre precision of {approx}10 {mu}m and allows changes to be observed on the live EBSP.

  5. Feasibility of using backscattered muons for archeological imaging

    Science.gov (United States)

    Bonal, N.; Preston, L. A.

    2013-12-01

    Use of nondestructive methods to accurately locate and characterize underground objects such as rooms and tools found at archeological sites is ideal to preserve these historic sites. High-energy cosmic ray muons are very sensitive to density variation and have been used to image volcanoes and archeological sites such as the Egyptian and Mayan pyramids. Muons are subatomic particles produced in the upper atmosphere that penetrate the earth's crust up to few kilometers. Their absorption rate depends on the density of the materials through which they pass. Measurements of muon flux rate at differing directions provide density variations of the materials between the muon source (cosmic rays and neutrino interactions) and the detector, much like a CAT scan. Currently, muon tomography can resolve features to the sub-meter scale making it useful for this type of work. However, the muon detector must be placed below the target of interest. For imaging volcanoes, the upper portion is imaged when the detector is placed on the earth's surface at the volcano's base. For sites of interest beneath the ground surface, the muon detector would need to be placed below the site in a tunnel or borehole. Placing the detector underground can be costly and may disturb the historical site. We will assess the feasibility of imaging the subsurface using upward traveling muons, to eliminate the current constraint of positioning the detector below the target. This work consists of three parts 1) determine the backscattered flux rate from theory, 2) distinguish backscattered from forward scattered muons at the detector, and 3) validate the theoretical results with field experimentation. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  6. Characterization of calcium and zinc spatial distributions at the fibrocartilage zone of bone-tendon junction by synchrotron radiation-based micro X-ray fluorescence analysis combined with backscattered electron imaging

    Science.gov (United States)

    Lu, Hongbin; Chen, Can; Wang, Zhanwen; Qu, Jin; Xu, Daqi; Wu, Tianding; Cao, Yong; Zhou, Jingyong; Zheng, Cheng; Hu, Jianzhong

    2015-09-01

    Tendon attaches to bone through a functionally graded fibrocartilage zone, including uncalcified fibrocartilage (UF), tidemark (TM) and calcified fibrocartilage (CF). This transition zone plays a pivotal role in relaxing load transfer between tendon and bone, and serves as a boundary between otherwise structurally and functionally distinct tissue types. Calcium and zinc are believed to play important roles in the normal growth, mineralization, and repair of the fibrocartilage zone of bone-tendon junction (BTJ). However, spatial distributions of calcium and zinc at the fibrocartilage zone of BTJ and their distribution-function relationship are not totally understood. Thus, synchrotron radiation-based micro X-ray fluorescence analysis (SR-μXRF) in combination with backscattered electron imaging (BEI) was employed to characterize the distributions of calcium and zinc at the fibrocartilage zone of rabbit patella-patellar tendon complex (PPTC). For the first time, the unique distributions of calcium and zinc at the fibrocartilage zone of the PPTC were clearly mapped by this method. The distributions of calcium and zinc at the fibrocartilage zone of the PPTC were inhomogeneous. A significant accumulation of zinc was exhibited in the transition region between UF and CF. The highest zinc content (3.17 times of that of patellar tendon) was found in the TM of fibrocartilage zone. The calcium content began to increase near the TM and increased exponentially across the calcified fibrocartilage region towards the patella. The highest calcium content (43.14 times of that of patellar tendon) was in the transitional zone of calcified fibrocartilage region and the patella, approximately 69 μm from the location with the highest zinc content. This study indicated, for the first time, that there is a differential distribution of calcium and zinc at the fibrocartilage zone of PPTC. These observations reveal new insights into region-dependent changes across the fibrocartilage zone of

  7. Ion beam polishing for three-dimensional electron backscattered diffraction

    DEFF Research Database (Denmark)

    Saowadee, Nath; Agersted, Karsten; Ubhi, H.S.;

    2013-01-01

    Serial sectioning by focused ion beam milling for three-dimensional electron backscatter diffraction (3D-EBSD) can create surface damage and amorphization in certain materials and consequently reduce the EBSD signal quality. Poor EBSD signal causes longer data acquisition time due to signal...... averaging and/or poor 3D-EBSD data quality. In this work a low kV focused ion beam was successfully implemented to automatically polish surfaces during 3D-EBSD of La- and Nb-doped strontium titanate of volume 12.6 × 12.6 × 3.0 μm. The key to achieving this technique is the combination of a defocused low k......V high current ion beam and line scan milling. The line scan was used to restrict polishing to the sample surface and the ion beam was defocused to ensure the beam contacted the complete sample surface. In this study 1 min polishing time per slice increases total acquisition time by approximately 3...

  8. Characterization of calcium and zinc spatial distributions at the fibrocartilage zone of bone–tendon junction by synchrotron radiation-based micro X-ray fluorescence analysis combined with backscattered electron imaging

    International Nuclear Information System (INIS)

    Tendon attaches to bone through a functionally graded fibrocartilage zone, including uncalcified fibrocartilage (UF), tidemark (TM) and calcified fibrocartilage (CF). This transition zone plays a pivotal role in relaxing load transfer between tendon and bone, and serves as a boundary between otherwise structurally and functionally distinct tissue types. Calcium and zinc are believed to play important roles in the normal growth, mineralization, and repair of the fibrocartilage zone of bone–tendon junction (BTJ). However, spatial distributions of calcium and zinc at the fibrocartilage zone of BTJ and their distribution–function relationship are not totally understood. Thus, synchrotron radiation-based micro X-ray fluorescence analysis (SR-μXRF) in combination with backscattered electron imaging (BEI) was employed to characterize the distributions of calcium and zinc at the fibrocartilage zone of rabbit patella–patellar tendon complex (PPTC). For the first time, the unique distributions of calcium and zinc at the fibrocartilage zone of the PPTC were clearly mapped by this method. The distributions of calcium and zinc at the fibrocartilage zone of the PPTC were inhomogeneous. A significant accumulation of zinc was exhibited in the transition region between UF and CF. The highest zinc content (3.17 times of that of patellar tendon) was found in the TM of fibrocartilage zone. The calcium content began to increase near the TM and increased exponentially across the calcified fibrocartilage region towards the patella. The highest calcium content (43.14 times of that of patellar tendon) was in the transitional zone of calcified fibrocartilage region and the patella, approximately 69 μm from the location with the highest zinc content. This study indicated, for the first time, that there is a differential distribution of calcium and zinc at the fibrocartilage zone of PPTC. These observations reveal new insights into region-dependent changes across the fibrocartilage

  9. Characterization of calcium and zinc spatial distributions at the fibrocartilage zone of bone–tendon junction by synchrotron radiation-based micro X-ray fluorescence analysis combined with backscattered electron imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Hongbin; Chen, Can; Wang, Zhanwen; Qu, Jin; Xu, Daqi [Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha 410008 (China); Wu, Tianding; Cao, Yong [Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha 410008 (China); Zhou, Jingyong; Zheng, Cheng [Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha 410008 (China); Hu, Jianzhong, E-mail: jianzhonghu@hotmail.com [Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha 410008 (China); Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha 410008 (China)

    2015-09-01

    Tendon attaches to bone through a functionally graded fibrocartilage zone, including uncalcified fibrocartilage (UF), tidemark (TM) and calcified fibrocartilage (CF). This transition zone plays a pivotal role in relaxing load transfer between tendon and bone, and serves as a boundary between otherwise structurally and functionally distinct tissue types. Calcium and zinc are believed to play important roles in the normal growth, mineralization, and repair of the fibrocartilage zone of bone–tendon junction (BTJ). However, spatial distributions of calcium and zinc at the fibrocartilage zone of BTJ and their distribution–function relationship are not totally understood. Thus, synchrotron radiation-based micro X-ray fluorescence analysis (SR-μXRF) in combination with backscattered electron imaging (BEI) was employed to characterize the distributions of calcium and zinc at the fibrocartilage zone of rabbit patella–patellar tendon complex (PPTC). For the first time, the unique distributions of calcium and zinc at the fibrocartilage zone of the PPTC were clearly mapped by this method. The distributions of calcium and zinc at the fibrocartilage zone of the PPTC were inhomogeneous. A significant accumulation of zinc was exhibited in the transition region between UF and CF. The highest zinc content (3.17 times of that of patellar tendon) was found in the TM of fibrocartilage zone. The calcium content began to increase near the TM and increased exponentially across the calcified fibrocartilage region towards the patella. The highest calcium content (43.14 times of that of patellar tendon) was in the transitional zone of calcified fibrocartilage region and the patella, approximately 69 μm from the location with the highest zinc content. This study indicated, for the first time, that there is a differential distribution of calcium and zinc at the fibrocartilage zone of PPTC. These observations reveal new insights into region-dependent changes across the fibrocartilage

  10. Scanning electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1998-01-01

    Scanning Electron Microscopy provides a description of the physics of electron-probe formation and of electron-specimen interations The different imaging and analytical modes using secondary and backscattered electrons, electron-beam-induced currents, X-ray and Auger electrons, electron channelling effects, and cathodoluminescence are discussed to evaluate specific contrasts and to obtain quantitative information

  11. X-ray backscatter imaging of nuclear materials

    Science.gov (United States)

    Chapman, Jeffrey Allen; Gunning, John E; Hollenbach, Daniel F; Ott, Larry J; Shedlock, Daniel

    2014-09-30

    The energy of an X-ray beam and critical depth are selected to detect structural discontinuities in a material having an atomic number Z of 57 or greater. The critical depth is selected by adjusting the geometry of a collimator that blocks backscattered radiation so that backscattered X-ray originating from a depth less than the critical depth is not detected. Structures of Lanthanides and Actinides, including nuclear fuel rod materials, can be inspected for structural discontinuities such as gaps, cracks, and chipping employing the backscattered X-ray.

  12. Photon beams for radiosurgery produced by laser Compton backscattering from relativistic electrons

    Science.gov (United States)

    Girolami, B.; Larsson, B.; Preger, M.; Schaerf, C.; Stepanek, J.

    1996-09-01

    The frontal collisions of a laser beam with relativistic electrons result in Compton-backscattered photons. The energy of these photons is dependent on the laser and electron energy in the range from kilo-electron-volts to tens of mega-electron-volts. In a sufficiently narrow backscattering angle the photons are nearly monochromatic. Over the past 30 years there have been several attempts to produce photon beams by laser backscattering from relativistic electrons stored in magnetic ring structures. One aim is to produce photons in the high mega-electron-volt energy range with fluxes useful for nuclear physics research; another is to produce photons in the high kilo-electron-volt energy range, which would be useful for medical applications, such as coronary angiography or treatment of tumour. Our present interest is to investigate the possibility of using 34 keV to 10 MeV photon beams for applications in stereotactic functional radiosurgery. We foresee the possibility of neurosurgical operations through the intact skull with precise and effective destruction of deeply lying millimetre-sized targets with minimal effects on intervening structures, high reproducibility and good prediction of the results. Our paper presents: a Monte Carlo study of radiosurgery based on cross firing with 34 keV to 100 MeV photon beams and 200 and 580 MeV proton beams, a theoretical description of the kinematics of Compton backscattering and estimates of the backscattered photon flux from several combinations of laser cavities at Nd:YAG (1.17 eV) and images/0031-9155/41/9/002/img8.gif" ALIGN="TOP"/> (0.117 eV) laser energies and electron storage rings energies in the range 0.1 - 1.3 GeV. As examples, existing magnetic structures, such as the images/0031-9155/41/9/002/img9.gif" ALIGN="TOP"/> Accumulator in the lower energy range and the Trieste Synchrotron Light Source ELETTRA in the higher energy range have been utilized in the calculations. The Monte Carlo study has shown that

  13. Quantitative measurements of Kikuchi bands in diffraction patterns of backscattered electrons using an electrostatic analyzer.

    Science.gov (United States)

    Went, M R; Winkelmann, A; Vos, M

    2009-09-01

    Diffraction patterns of backscattered electrons can provide important crystallographic information with high spatial resolution. Recently, the dynamical theory of electron diffraction was applied to reproduce in great detail backscattering patterns observed in the scanning electron microscope (SEM). However, a fully quantitative comparison of theory and experiment requires angle-resolved measurements of the intensity and the energy of the backscattered electrons, which is difficult to realize in an SEM. This paper determines diffraction patterns of backscattered electrons using an electrostatic analyzer, operating at energies up to 40 keV with sub-eV energy resolution. Measurements are done for different measurement geometries and incoming energies. Generally a good agreement is found between theory and experiment. This spectrometer also allows us to test the influence of the energy loss of the detected electron on the backscattered electron diffraction pattern. It is found that the amplitude of the intensity variation decreases only slowly with increasing energy loss from 0 to 60 eV.

  14. Misorientations in [001] magnetite thin films studied by electron backscatter diffraction and magnetic force microscopy

    Science.gov (United States)

    Koblischka-Veneva, A.; Koblischka, M. R.; Wei, J. D.; Zhou, Y.; Murphy, S.; Mücklich, F.; Hartmann, U.; Shvets, I. V.

    2007-05-01

    Magnetite thin films grown on [001] oriented MgO substrates are analyzed by means of electron backscatter diffraction (EBSD) analysis and magnetic force microscopy in applied fields. The EBSD technique enables the crystallographic orientation of individual grains to be determined with a high spatial resolution up to 20nm on such ceramic samples. A high image quality of the recorded Kikuchi patterns was achieved enabling multiphase scans and high spatial resolution measurements. Upon annealing in air, the magnetic properties of the magnetite thin films were found to change considerably. Using the EBSD analysis, we find that misoriented grains remaining after the annealing step form small islands with a size of about 100nm. The size and distribution of these islands correspond well to the observations of antiferromagnetic pinning centers within the magnetic domain structures carried out by magnetic force microscopy on the same samples.

  15. Contribution of backscattered electrons to the total electron yield produced in collisions of 8–28 keV electrons with tungsten

    Indian Academy of Sciences (India)

    R K Yadav; R Shanker

    2007-03-01

    It is shown experimentally that under energetic electron bombardment the backscattered electrons from solid targets contribute significantly (∼ 80%) to the observed total electron yield, even for targets of high backscattering coefficients. It is further found that for tungsten ( = 74) with a backscattering coefficient of about 0.50, about 20% of the total electron yield is contributed by the total secondary electrons for impact energies in the range of 8–28 keV. The yield of true backscattered electrons at normal incidence (0), total secondary electrons () and the total electron yield (tot) produced in collisions of 8–28 keV electrons with W have been measured and compared with predictions of available theories. The present results indicate that the constant-loss of primary electrons in the target plays a significant role in producing the secondary electrons and that it yields a better fit to the experiment compared to the power-law.

  16. Electron back-scattering coefficient below 5 keV: Analytical expressions and surface-barrier effects

    Science.gov (United States)

    Cazaux, J.

    2012-10-01

    Simple analytical expressions for the electron backscattering coefficient, η, are established from published data obtained in the ˜0.4-5 keV range for 21 elements ranging from Be to Au. They take into account the decline in η with a decrease in energy E° for high-Z elements and the reverse behavior for low-Z elements. The proposed expressions for η (E°) lead to crossing energies situated in the 0.4-1 keV range and they may be reasonably extended to any of the other elements—via an interpolation procedure—to metallic alloys and probably to compounds. The influence of the surface barrier on the escape probability of the back-scattered electrons is next evaluated. This evaluation provides a theoretical basis to explain the observed deviation between various published data as a consequence of surface contamination or oxidation. Various practical applications and strategies are deduced for the η-measurements in dedicated instruments as well for the image interpretation in low voltage scanning electron microscopy based on the backscattered electron detection. In this microscopy, the present investigation allows to generalize the scarce contrast changes and contrast reversals previously observed on multi elemental samples and it suggests the possibility of a new type of contrast: the work function contrast.

  17. Monte Carlo simulation of MOSFET dosimeter for electron backscatter using the GEANT4 code.

    Science.gov (United States)

    Chow, James C L; Leung, Michael K K

    2008-06-01

    The aim of this study is to investigate the influence of the body of the metal-oxide-semiconductor field effect transistor (MOSFET) dosimeter in measuring the electron backscatter from lead. The electron backscatter factor (EBF), which is defined as the ratio of dose at the tissue-lead interface to the dose at the same point without the presence of backscatter, was calculated by the Monte Carlo simulation using the GEANT4 code. Electron beams with energies of 4, 6, 9, and 12 MeV were used in the simulation. It was found that in the presence of the MOSFET body, the EBFs were underestimated by about 2%-0.9% for electron beam energies of 4-12 MeV, respectively. The trend of the decrease of EBF with an increase of electron energy can be explained by the small MOSFET dosimeter, mainly made of epoxy and silicon, not only attenuated the electron fluence of the electron beam from upstream, but also the electron backscatter generated by the lead underneath the dosimeter. However, this variation of the EBF underestimation is within the same order of the statistical uncertainties as the Monte Carlo simulations, which ranged from 1.3% to 0.8% for the electron energies of 4-12 MeV, due to the small dosimetric volume. Such small EBF deviation is therefore insignificant when the uncertainty of the Monte Carlo simulation is taken into account. Corresponding measurements were carried out and uncertainties compared to Monte Carlo results were within +/- 2%. Spectra of energy deposited by the backscattered electrons in dosimetric volumes with and without the lead and MOSFET were determined by Monte Carlo simulations. It was found that in both cases, when the MOSFET body is either present or absent in the simulation, deviations of electron energy spectra with and without the lead decrease with an increase of the electron beam energy. Moreover, the softer spectrum of the backscattered electron when lead is present can result in a reduction of the MOSFET response due to stronger

  18. AnyStitch: a tool for combining electron backscatter diffraction data sets.

    Science.gov (United States)

    Pilchak, A L; Shiveley, A R; Tiley, J S; Ballard, D L

    2011-10-01

    Recent advances in electron backscatter diffraction equipment and software have permitted increased data acquisition rates on the order of hundreds of points per second with additional increases in the foreseeable future likely. This increase in speed allows users to collect data from statistically significant areas of samples by combining beam-control scans and automated stage movements. To facilitate data analysis, however, the individual tiles must be combined, or stitched, into a single data set. In this paper, we describe a matlab(®) (The Mathworks, Inc., Natick, MA, USA) program to facilitate stitching of electron backscatter diffraction data. The method offers users a wide range of controls for tile placement including independent overlaps for horizontal and vertical tiles and also includes a parameter to account for systematic stage positioning errors or improperly calibrated scan rotation. The code can stitch data collected on either square or hexagonal grids and contains a function to reduce the resolution of square grid data if the resulting file is too large (or has too many grains) to be opened by the analysis software. The software was primarily written to work with TSL(®) OIM™ data sets and includes a function to quickly read compressed *.osc files into a variable in the matlab(®) workspace as opposed to using slower, text-reading functions. The output file is in *.ang format and can be opened directly by TSL(®) OIM™ Analysis software. A set of functions to facilitate stitching of text-based *.ctf files produced by Oxford Instruments HKL systems are also included. Finally, the code can also be used to combine *.tif images to produce a montage. The source code, a graphical user interface and a compiled version of the software was made available in the online version of this paper.

  19. Mitigating the effect of optical back-scatter in multispectral underwater imaging

    International Nuclear Information System (INIS)

    Multispectral imaging is a very useful technique for extracting information from the underwater world. However, optical back-scatter changes the intensity value in each spectral band and this distorts the estimated spectrum. In this work, a filter is used to detect the level of optical back-scatter in each spectral band from a set of multispectral images. Extraction of underwater object spectra can be done by subtracting the estimated level of optical back-scatter and scaling the remainder in each spectral band from the captured image in the corresponding band. An experiment has been designed to show the performance of the proposed filter for correcting the set of multispectral underwater images and recovering the pixel spectra. The multispectral images are captured by a B/W CCD digital camera with a fast tunable liquid-crystal filter in 33 narrow spectral bands in clear and different levels of turbid water. Reference estimates for the optical back-scatter spectra are found by comparing a clear and a degraded set of multispectral images. The accuracy and consistency of the proposed method, the extended Oakley–Bu cost function, is examined by comparing the estimated values with the reference level of an optical back-scatter spectrum. The same comparison is made for the simple estimation approach. The results show that the simple method is not reliable and fail to estimate the level of optical back-scatter spectrum accurately. The results from processing experimental images in turbid water show that the effect of optical back-scatter can be mitigated in the image of each spectral band and, as a result, the spectra of the object can be recovered. However, for a very high level of turbid water the recovery is limited because of the effect of extinction. (paper)

  20. Advantages and artifacts of higher order modes in nanoparticle-enhanced backscattering Raman imaging.

    Science.gov (United States)

    Schultz, Zachary D; Stranick, Stephan J; Levin, Ira W

    2009-12-01

    In order to facilitate nanoparticle-enhanced Raman imaging of complicated biological specimens, we have examined the use of higher order modes with radial and azimuthal polarizations focused onto a Au nanoparticle atomic force microscope (AFM) tip utilizing a backscattering reflection configuration. When comparing the Raman intensity profiles with the observed sample topography, the radial-polarized configuration demonstrates enhanced spatial resolution. This enhanced resolution results from the direction of the induced electron oscillation in the metal nanoparticle oriented by the electromagnetic field at the laser focus. The electric field component along the direction of laser propagation, attendant to the radial polarization, creates an enhanced field along the z-axis and normal to the sample. Substantial enhancement is observed utilizing an intermediate numerical aperture objective (NA = 0.7), necessary for backscattering measurements. The azimuthal polarization, similar to linear polarization, results in an enhanced field predominantly parallel to the sample, resulting in imaging artifacts. The Raman intensity profiles observed as the exciting laser polarization is switched between either a radially polarized or an azimuthally polarized state illustrate these imaging artifacts. Because azimuthal polarization arises readily from changes in the incident polarization onto the mode converter, the results presented here aid in identifying such artifacts when analyzing nanoparticle-enhanced Raman spectroscopic images. Due to the power law decay of the enhanced field, an enhancement orientation normal to the sample enables contrast between structures smaller than the tip dimensions as the apex of the nanoparticle tip, where the enhancement is strongest, passes over the sample. These effects are demonstrated using both carbon nanotube and fixed biological samples. PMID:19947663

  1. Crystallographic Relationships of Silicate-hosted Magnetite Inclusions Determined with Electron Backscatter Pattern Indexing (EBSP)

    Science.gov (United States)

    Feinberg, J. M.; Wenk, H.; Renne, P. R.; Scott, G. R.

    2002-12-01

    Crystallographically controlled laths of magnetite exsolved in silicates such as clinopyroxene and plagioclase are common features in gabbros and mafic granulite facies rocks. As the inclusions cool below the Curie temperature of magnetite (580°C) they record a component of the direction and intensity of the Earth's ambient magnetic field. The extreme anisotropy of the inclusions' aspect ratio allows them to retain an unusually stable magnetization, as exemplified by their single-domain behavior. In order to transform these magnetite inclusions into a useful paleomagnetic tool it is necessary to clearly describe the epitaxial relationship between the magnetite and its host silicate phases. In the past the crystallographic orientation of magnetite inclusions and their host silicates were determined using single-crystal X-ray diffraction or diffraction patterns obtained with a transmission electron microscope. Although both of these techniques are ultimately successful, they are time consuming and cumbersome. The Electron Backscatter Diffraction Pattern (EBSP) technique is an alternative approach that uses diffraction patterns of Kikuchi bands generated in a scanning electron microscope. The geometric relationships between intersecting Kikuchi bands can be used to determine the orientation of a crystal. Generally the EBSP technique is used to determine preferred orientation patterns in aggregates. However, in this application we use it to investigate local crystallographic relationships. First, inclusions in a thin section are visualized on a backscattered electron image and verified chemically with an EDX signal. Then EBSPs are produced for both the host silicate and the magnetite inclusions and the orientation relationship is ascertained. The EBSP technique's straightforward sample preparation and rapid measurement time, combined with the broad accessibility of scanning electron microscopes allow scientists to more efficiently determine crystallographic

  2. Multi-beam backscatter image data processing techniques employed to EM 1002 system

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, W.A.; Chakraborty, B.

    data for bathymetric depths such as backscatter images. The available algorithms are found to be limited in application aspects from the scientific user point of view. Moreover output file formats are as decided by manufacturer, which brings... incompatibility issues with other analyzing other systems such as ArcGIS etc [5]. Due to these problems, during the past we have developed algorithms for processing the backscatter intensities for other multi-beam systems (Hydrosweep -manufactured by STN ATLAS...

  3. Cyclic bending experiments on free-standing Cu micron lines observed by electron backscatter diffraction

    International Nuclear Information System (INIS)

    Polycrystalline Cu samples 20 × 20 μm2 in size were cyclically bent inside a scanning electron microscope until fracture occurred. The microstructural changes were investigated by secondary electron imaging and electron backscatter diffraction. The in situ experiments revealed that, for the coarse-grained samples, it is not the external stress that dominates the cyclic deformation, but the local internal strength. This is in strong contrast to macroscopic bending samples, where deformation always happens near the fixed end of the bending beam and decreases constantly with increasing distance from the fixation. For micron-sized polycrystalline samples, the grain dimensions, dislocation density evolution and grain orientation (Taylor factor) can define the location of failure if the grain size and sample diameter become similar in size. A comparison with cyclic in situ tension–tension experiments (ratio of minimum stress to maximum stress R ≈ 0) reveals that cyclic bending experiments (R ≈ −1) undergo bulk-like fatigue deformation with extrusions/intrusions, in contrast to the experiments with R ≈ 0. Both the cyclic tension–tension and bending experiments can be described by a Basquin equation, although different mechanisms lead to failure of the samples

  4. Analysis of Kikuchi band contrast reversal in electron backscatter diffraction patterns of silicon.

    Science.gov (United States)

    Winkelmann, Aimo; Nolze, Gert

    2010-02-01

    We analyze the contrast reversal of Kikuchi bands that can be seen in electron backscatter diffraction (EBSD) patterns under specific experimental conditions. The observed effect can be reproduced using dynamical electron diffraction calculations. Two crucial contributions are identified to be at work: First, the incident beam creates a depth distribution of incoherently backscattered electrons which depends on the incidence angle of the beam. Second, the localized inelastic scattering in the outgoing path leads to pronounced anomalous absorption effects for electrons at grazing emission angles, as these electrons have to go through the largest amount of material. We use simple model depth distributions to account for the incident beam effect, and we assume an exit angle dependent effective crystal thickness in the dynamical electron diffraction calculations. Very good agreement is obtained with experimental observations for silicon at 20keV primary beam energy.

  5. Image restoration techniques using Compton backscatter imaging for the detection of buried land mines

    Science.gov (United States)

    Wehlburg, Joseph C.; Keshavmurthy, Shyam P.; Watanabe, Yoichi; Dugan, Edward T.; Jacobs, Alan M.

    1995-06-01

    Earlier landmine imaging systems used two collimated detectors to image objects. These systems had difficulty in distinguishing between surface features and buried features. Using a combination of collimated and uncollimated detectors in a Compton backscatter imaging (CBI) system, allows the identification of surface and buried features. Images created from the collimated detectors contain information about the surface and the buried features, while the uncollimated detectors respond (approximately 80%) to features on the surface. The analysis of surface features are performed first, then these features can be removed and the buried features can be identified. Separation of the surface and buried features permits the use of a globbing algorithm to define regions of interest that can then be quantified [area, Y dimension, X dimension, and center location (xo, yo)]. Mine composition analysis is also possible because of the properties of the four detector system. Distinguishing between a pothole and a mine, that was previously very difficult, can now be easily accomplished.

  6. Quantitative microstructure characterization of self-annealed copper films with electron backscatter diffraction

    DEFF Research Database (Denmark)

    Pantleon, Karen; Gholinia, A.; Somers, Marcel A. J.

    2008-01-01

    Electron backscatter diffraction (EBSD) was applied to analyze cross sections of self-annealed copper electrodeposits, for which earlier the kinetics of self-annealing had been investigated by in-situ X-ray diffraction (XRD). The EBSD investigations on the grain size, grain boundary character and...... microstructure evolution at room temperature (self-annealing)....

  7. On the optimum resolution of transmission-electron backscattered diffraction (t-EBSD)

    NARCIS (Netherlands)

    van Bremen, R.; Gomes, D. Ribas; de Jeer, L. T. H.; Ocelik, V.; De Hosson, J. Th. M.

    2016-01-01

    The work presented aims at determining the optimum physical resolution of the transmission-electron backscattered diffraction (t-EBSD) technique. The resolution depends critically on intrinsic factors such as the density, atomic number and thickness of the specimen but also on the extrinsic experime

  8. Time-lapse misorientation maps for the analysis of electron backscatter diffraction data from evolving microstructures

    NARCIS (Netherlands)

    Wheeler, J.; Cross, A.; Drury, M.; Hough, R.M.; Mariani, E.; Piazolo, S.; Prior, D.J.

    2011-01-01

    A “time-lapse misorientation map” is defined here as a map which shows the orientation change at each point in an evolving crystalline microstructure between two different times. Electron backscatter diffraction data from in situ heating experiments can be used to produce such maps, which then highl

  9. An automated method of quantifying ferrite microstructures using electron backscatter diffraction (EBSD) data

    Energy Technology Data Exchange (ETDEWEB)

    Shrestha, Sachin L., E-mail: sachin.shrestha@sydney.edu.au [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006 (Australia); Breen, Andrew J.; Trimby, Patrick [Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); Proust, Gwénaëlle [School of Civil Engineering, The University of Sydney, NSW 2006 (Australia); Ringer, Simon P.; Cairney, Julie M. [School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006 (Australia); Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia)

    2014-02-01

    The identification and quantification of the different ferrite microconstituents in steels has long been a major challenge for metallurgists. Manual point counting from images obtained by optical and scanning electron microscopy (SEM) is commonly used for this purpose. While classification systems exist, the complexity of steel microstructures means that identifying and quantifying these phases is still a great challenge. Moreover, point counting is extremely tedious, time consuming, and subject to operator bias. This paper presents a new automated identification and quantification technique for the characterisation of complex ferrite microstructures by electron backscatter diffraction (EBSD). This technique takes advantage of the fact that different classes of ferrite exhibit preferential grain boundary misorientations, aspect ratios and mean misorientation, all of which can be detected using current EBSD software. These characteristics are set as criteria for identification and linked to grain size to determine the area fractions. The results of this method were evaluated by comparing the new automated technique with point counting results. The technique could easily be applied to a range of other steel microstructures. - Highlights: • New automated method to identify and quantify ferrite microconstituents in HSLA steels is presented. • Unique characteristics of the ferrite microconstituents are investigated using EBSD. • Characteristics of ferrite microconstituents are exploited to identify the type of ferrite grains within the steel's microstructures. • The identified ferrite grains are linked to their associated grain's size for area fraction calculations.

  10. Electron backscatter diffraction analysis of a CZT growth tip from a vertical gradient freeze furnace

    Energy Technology Data Exchange (ETDEWEB)

    Sundaram, S. K.; Henager, C. H.; Edwards, D. J.; Schemer-Kohrn, A. L.; Bliss, M.; Riley, B. R.

    2011-08-15

    Electron backscatter diffraction (EBSD) was used to characterize the growth-tip region of a 4.2-cm diameter CdZnTe (CZT) boule grown using low-pressure Bridgman method in a vertical gradient freeze furnace. The boule was sectioned and polished and a section taken along the boule longitudinal centerline with an approximate surface area of 1-cm2 was used for optical and scanning electron microscopy. A collage was assembled using EBSD/SEM images to show morphological features, e.g., twin structure, grain structure, and overall crystal growth direction. Severely twinned regions originating from the tip and side walls were observed. The overall growth orientation was close to (1 1 0) and (1 1 2) directions. In some regions, the (0 0 1) poles of the CZT matrix aligned with the growth direction, while twins aligned such that (1 1 1) and (1 1 2) poles aligned with the growth direction. Finally, in some other areas, (1 1 2) or (0 1 1) poles of the CZT matrix aligned with the growth direction. New relationships between the CZT matrix and large Te polycrystalline particles were revealed: {1 1 2-}CZTΙΙ{1 1- 0 0}Te and {0 0 1}CZTII{0 1-1-1}Te.

  11. Single-shot radiography using X-rays from Compton-backscattering with laser-wakefield accelerated electron beams

    CERN Document Server

    Döpp, A; Thaury, C; Gautier, J; Andriyash, I; Lifschitz, A; Goddet, J-P; Tafzi, A; Malka, V; Rousse, A; Phuoc, K Ta

    2015-01-01

    We present results from the production of high energy femtosecond X-rays by Compton-backscattering of an intense femtosecond laser pulse with quasi-monoenergetic laser-accelerated electron beams using a plasma mirror. In our parameter regime electrons of $\\sim$ 150 MeV peak energy emit a high energy radiation beam with a broad spectrum extending up to $\\sim$ 500 keV. The photon yield from the source is sufficiently high to illuminate a centimeter-size sample placed 90 centimeters behind the source and record a single-shot radiograph. The small diameter of the laser-accelerated electron beams translates into a micrometer X-ray source size, making it a promising candidate for advanced X-ray imaging techniques as e.g. propagation-based phase contrast imaging.

  12. Skeletal growth phases of the cold-water coral Lophelia pertusa shown by scanning electron microscope and electron backscatter diffraction

    Science.gov (United States)

    Mouchi, Vincent; Vonlanthen, Pierre; Verrecchia, Eric P.; Crowley, Quentin G.

    2016-04-01

    Lophelia pertusa is a cold-water coral, which may form reefs by the association of multiple coralites within which a polyp lives. Each individual polyp builds an aragonite skeleton by an initial phase of early mineralization (traditionally referred to as centres of calcification) from which aragonite fibres grow in thickening deposits. The skeleton wall features successive optically opaque and translucent bands previously attributed to different regimes of growth as either uniform in crystal orientation (translucent bands) or with a chaotic organization (opaque bands). The processes involved in any organizational changes are still unknown. Microlayers in the coral wall, which represent separate periods of skeletal growth, have been recently identified and described. These growth patterns are readily visible under scanning electron microscope (SEM) after etching in dilute formic acid, but they do not necessarily form continuously visible structures. Here we present high quality SEM images and electron backscatter diffraction (EBSD) maps to study aragonite fibre orientation across the wall of L. pertusa. Both microlayers and opaque and translucent bands are compared to the crystallographic orientation of the aragonite fibres. EBSD maps and SEM images indicate that aragonite fibres do not exhibit a chaotic orientation, even in opaque bands. The absence of continuity of microlayers is partially explained by an association of multiple crystallographic preferred orientations of aragonite fibres. In the case of L. pertusa, careful textural characterisation is necessary prior to elemental or isotope analysis in order to select a skeletal transect representing a linear and continuous time period.

  13. Image combination enhancement method for X-ray compton back-scattering security inspection body scanner

    International Nuclear Information System (INIS)

    As for X-ray Compton Back-Scattering (CBS) body scanner, image clearness is very important for the performance of detecting the contraband hidden on the body. A new image combination enhancement method is provided based on characteristics of CBS body images and points of human vision. After processed by this method, the CBS image will be obviously improved with clear levels, distinct outline and uniform background. (authors)

  14. Quantitative Test of the Evolution of Geant4 Electron Backscattering Simulation

    CERN Document Server

    Basaglia, Tullio; Hoff, Gabriela; Kim, Chan Hyeong; Kim, Sung Hun; Pia, Maria Grazia; Saracco, Paolo

    2016-01-01

    Evolutions of Geant4 code have affected the simulation of electron backscattering with respect to previously published results. Their effects are quantified by analyzing the compatibility of the simulated electron backscattering fraction with a large collection of experimental data for a wide set of physics configuration options available in Geant4. Special emphasis is placed on two electron scattering implementations first released in Geant4 version 10.2: the Goudsmit-Saunderson multiple scattering model and a single Coulomb scattering model based on Mott cross section calculation. The new Goudsmit-Saunderson multiple scattering model appears to perform equally or less accurately than the model implemented in previous Geant4 versions, depending on the electron energy. The new Coulomb scattering model was flawed from a physics point of view, but computationally fast in Geant4 version 10.2; the physics correction released in Geant4 version 10.2p01 severely degrades its computational performance. Evolutions in ...

  15. 2D Doppler backscattering using synthetic aperture microwave imaging of MAST edge plasmas

    OpenAIRE

    Thomas, D.A.; Brunner, K.J.; Freethy, S.J.; Huang, B.K.; Shevchenko, V. F.; Vann, R. G. L.

    2016-01-01

    Doppler backscattering (DBS) is already established as a powerful diagnostic; its extension to 2D enables imaging of turbulence characteristics from an extended region of the cut-off surface. The Synthetic Aperture Microwave Imaging (SAMI) diagnostic has conducted proof-of-principle 2D DBS experiments of MAST edge plasma. SAMI actively probes the plasma edge using a wide (±40° vertical and horizontal) and tuneable (10–34.5 GHz) beam. The Doppler backscattered signal is digitised in vector for...

  16. Coherent backscattering of inelastic photons from atoms and their mirror images

    CERN Document Server

    Moriya, P H; Teixeira, R Celistrino; Máximo, C E; Piovella, N; Bachelard, R; Kaiser, R; Courteille, Ph W

    2016-01-01

    Coherent backscattering is a coherence effect in the propagation of waves through disordered media involving two or more scattering events. Here, we report on the observation of coherent backscattering from individual atoms and their mirror images. This system displays two important advantages: First, the effect can be observed at low optical densities, which allows to work in very dilute clouds or far from resonance. Second, due to the fact that the radiation of an atom interferes constructively with that of its own image, the phenomenon is much more robust to dephasing induced by strong saturation. In particular, the contribution of inelastically scattered photons to the interference process is demonstrated.

  17. Geometrically necessary dislocation densities in olivine obtained using high-angular resolution electron backscatter diffraction.

    Science.gov (United States)

    Wallis, David; Hansen, Lars N; Ben Britton, T; Wilkinson, Angus J

    2016-09-01

    Dislocations in geological minerals are fundamental to the creep processes that control large-scale geodynamic phenomena. However, techniques to quantify their densities, distributions, and types over critical subgrain to polycrystal length scales are limited. The recent advent of high-angular resolution electron backscatter diffraction (HR-EBSD), based on diffraction pattern cross-correlation, offers a powerful new approach that has been utilised to analyse dislocation densities in the materials sciences. In particular, HR-EBSD yields significantly better angular resolution (densities to be analysed. We develop the application of HR-EBSD to olivine, the dominant mineral in Earth's upper mantle by testing (1) different inversion methods for estimating geometrically necessary dislocation (GND) densities, (2) the sensitivity of the method under a range of data acquisition settings, and (3) the ability of the technique to resolve a variety of olivine dislocation structures. The relatively low crystal symmetry (orthorhombic) and few slip systems in olivine result in well constrained GND density estimates. The GND density noise floor is inversely proportional to map step size, such that datasets can be optimised for analysing either short wavelength, high density structures (e.g. subgrain boundaries) or long wavelength, low amplitude orientation gradients. Comparison to conventional images of decorated dislocations demonstrates that HR-EBSD can characterise the dislocation distribution and reveal additional structure not captured by the decoration technique. HR-EBSD therefore provides a highly effective method for analysing dislocations in olivine and determining their role in accommodating macroscopic deformation. PMID:27337604

  18. Advanced microstructural analysis of ferrite materials by means of electron backscatter diffraction (EBSD)

    Science.gov (United States)

    Koblischka-Veneva, A.; Koblischka, M. R.; Mücklich, F.

    2010-05-01

    The analysis of the achieved texture is of great importance for the performance of ferrite materials, either bulk or thin films. The recently developed electron backscatter diffraction (EBSD) technique enables a spatially resolved study of the crystallographic orientations by means of recording of Kikuchi patterns. To our knowledge, such a thorough EBSD analysis was not yet performed in any oxidic magnetic material, and only very recently on magnetite thin films by us. A good surface polishing/cleaning is essential for this analysis, as the method requires an undisturbed surface area for a high image quality (IQ). This information is recorded to each measured Kikuchi pattern, together with a parameter describing the quality of indexation. Here, the spatially highly resolved EBSD mappings provide additional information as compared to the standard analysis techniques, which can contribute to an optimization of the growth process. Furthermore, an analysis of the grain aspect ratio is possible which provides further insight to the microstructural dependence of the magnetic properties of ferrites.

  19. Forty-five degree backscattering-mode nonlinear absorption imaging in turbid media.

    Science.gov (United States)

    Cui, Liping; Knox, Wayne H

    2010-01-01

    Two-color nonlinear absorption imaging has been previously demonstrated with endogenous contrast of hemoglobin and melanin in turbid media using transmission-mode detection and a dual-laser technology approach. For clinical applications, it would be generally preferable to use backscattering mode detection and a simpler single-laser technology. We demonstrate that imaging in backscattering mode in turbid media using nonlinear absorption can be obtained with as little as 1-mW average power per beam with a single laser source. Images have been achieved with a detector receiving backscattered light at a 45-deg angle relative to the incoming beams' direction. We obtain images of capillary tube phantoms with resolution as high as 20 microm and penetration depth up to 0.9 mm for a 300-microm tube at SNR approximately 1 in calibrated scattering solutions. Simulation results of the backscattering and detection process using nonimaging optics are demonstrated. A Monte Carlo-based method shows that the nonlinear signal drops exponentially as the depth increases, which agrees well with our experimental results. Simulation also shows that with our current detection method, only 2% of the signal is typically collected with a 5-mm-radius detector. PMID:20459249

  20. Strongly Enhanced Stimulated Brillouin Backscattering in an Electron-Positron Plasma

    Science.gov (United States)

    Edwards, Matthew R.; Fisch, Nathaniel J.; Mikhailova, Julia M.

    2016-01-01

    Stimulated Brillouin backscattering of light is shown to be drastically enhanced in electron-positron plasmas, in contrast to the suppression of stimulated Raman scattering. A generalized theory of three-wave coupling between electromagnetic and plasma waves in two-species plasmas with arbitrary mass ratios, confirmed with a comprehensive set of particle-in-cell simulations, reveals violations of commonly held assumptions about the behavior of electron-positron plasmas. Specifically, in the electron-positron limit three-wave parametric interaction between light and the plasma acoustic wave can occur, and the acoustic wave phase velocity differs from its usually assumed value.

  1. Time-lapse misorientation maps for the analysis of electron backscatter diffraction data from evolving microstructures

    International Nuclear Information System (INIS)

    A 'time-lapse misorientation map' is defined here as a map which shows the orientation change at each point in an evolving crystalline microstructure between two different times. Electron backscatter diffraction data from in situ heating experiments can be used to produce such maps, which then highlight areas of microstructural change and also yield statistics indicative of how far different types of boundary (with different misorientations) have moved.

  2. Thomson backscattering diagnostics of nanosecond electron bunches in high space charge regime

    OpenAIRE

    B. Paroli

    2012-01-01

    The intra-beam repulsions play a significant role in determining the performances of free-electron devices when an high brilliance of the beam is required. The transversal and longitudinal spread of the beam, its energy and density are fundamental parameters in any beam experiment and different beam diagnostics are available to measure such parameters. A diagnostic method based on the Thomson backscattering of a laser beam impinging on the particle beam is proposed in this work for the study ...

  3. Landmine Detection: on the Role of Soil Composition in the Imaging Capabilities of Gamma-ray Compton Backscattering

    International Nuclear Information System (INIS)

    Two issues related with the use of γ-ray Compton backscattering as an imaging technique are addressed: γ-soil interaction, and image processing. Promising methodologies are described in both topics. (author)

  4. Three-Dimensional Backscatter X-Ray Imaging System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall objective of the proposal is to design, develop and demonstrate a potentially portable Compton x-ray scatter 3D-imaging system by using specially...

  5. Three-Dimensional Backscatter X-Ray Imaging System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA application requires a system that can generate 3D images of non-metallic material when access is limited to one side of the material. The objective of...

  6. Measurement of the BESSY II electron beam energy by Compton-backscattering of laser photons

    CERN Document Server

    Klein, R; Thornagel, R; Brandt, G; Görgen, R; Ulm, G

    2002-01-01

    Accurate knowledge of all storage ring parameters is essential for the Physikalisch-Technische Bundesanstalt (PTB) to operate the electron storage ring BESSY II as a primary source standard. One parameter entering the Schwinger equation for the calculation of the spectral photon flux of bending magnet radiation is the electron beam energy. So at BESSY II the electron beam energy is measured by two independent techniques one of which is described in this paper: the photons from a CO sub 2 -laser are scattered in a head-on collision with the stored electrons. From the spectrum of the backscattered photons that are detected by an energy-calibrated HPGe detector the electron beam energy can be determined. The experimental set-up at the BESSY II electron storage ring as well as the current experimental status are described for operation of the storage ring at the energies of 900 and 1700 MeV.

  7. Experimental observation of the strong influence of crystal orientation on Electron Rutherford Backscattering Spectra

    Science.gov (United States)

    Vos, Maarten; Aizel, Koceila; Winkelmann, Aimo

    2010-06-01

    In Electron Rutherford Backscattering Spectroscopy (ERBS) energetic electrons (in our case up to 40 keV) impinge on a target and one measures the energy of elastically scattered electrons. This energy depends on the mass of the scattering atom, due to the recoil effect. This technique thus provides information about the sample composition. For single crystals the interaction of the projectile electron with the crystal potential modifies the angular intensity distribution of the scattered electrons. This leads, for example, to the well-known Kikuchi patterns. Here we investigate if such modified angular distribution has any influence on the intensity ratio of the observed elastic peaks in ERBS. Dramatic effects are found. Implications of these observations for quantitative surface analysis using energetic electrons are discussed.

  8. Backscattering of fast electrons from solids within a multiple collision model

    Science.gov (United States)

    Vukanic, J.; Davidovic, D. M.

    2008-07-01

    Reflection of electrons from solids is treated by the approximate analytic solution of the linearized transport equation. Scattering of electrons on target atoms is determined by the screened Coulomb interaction and the energy loss due to interaction with target electrons is defined by Bethe- Bloch formula. The anisotropic P_3 approximation of the collision integral is utilized and the Bolzmann transport equation is Laplace transformed in relative path length and solved by applying the DP0 technique. The approach is applicable in a wide range of electron energy --from several tens of keV to several MeV- and for materials where the mean number of collisions of an electron with target atoms during slowing down is large. Analytic expressions for energy distribution of backscattered electrons as well as for the particle and energy reflection coefficients were derived. Comparison of our results with data of the computational bipartition model is presented.

  9. Advantages and Artifacts of Higher Order Modes in Nanoparticle Enhanced Back-Scattering Raman Imaging

    OpenAIRE

    Schultz, Zachary D.; Stephan J. Stranick; Levin, Ira W.

    2009-01-01

    In order to facilitate nanoparticle enhanced Raman imaging of complicated biological specimens, we have examined the use of higher order modes with radial and azimuthal polarizations focused onto a Au nanoparticle AFM tip utilizing a back-scattering reflection configuration. When comparing the Raman intensity profiles with the observed sample topography, the radial polarized configuration demonstrates enhanced spatial resolution. This enhanced resolution results from the direction of the indu...

  10. Use of Reciprocal Lattice Layer Spacing in Electron Backscatter Diffraction Pattern Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Eades, J.A.; Michael, J.R.

    1999-05-10

    In the scanning electron microscope (SEM), using electron backscattered diffraction (EBSD), it is possible to measure the spacing of the layers in the reciprocal lattice. These values are of great use in confirming the identification of phases. The technique derives the layer spacing from the HOLZ rings which appear in patterns from many materials. The method adapts results from convergent-beam electron diffraction (CBED) in the transmission electron microscope (TEM). For many materials the measured layer spacing compares well with the calculated layer spacing. A noted exception is for higher atomic number materials. In these cases an extrapolation procedure is described that requires layer spacing measurements at a range of accelerating voltages. This procedure is shown to improves the accuracy of the technique significantly. The application of layer spacing measurements in EBSD is shown to be of use for the analysis of two polytypes of SiC.

  11. Seafloor Backscatter Image of North of Santa Rosa Island, Channel Islands National Marine Sanctuary (8m resolution tif)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents an 8 meter resolution backscatter of the seafloor south of Santa Rosa Island in Channel Islands National Marine Sanctuary. It was acquired...

  12. Electron backscatter diffraction analysis applied to [0 0 1] magnetite thin films grown on MgO substrates

    Science.gov (United States)

    Koblischka-Veneva, A.; Koblischka, M. R.; Zhou, Y.; Murphy, S.; Mücklich, F.; Hartmann, U.; Shvets, I. V.

    2007-09-01

    Electron backscatter diffraction (EBSD) analysis is applied to [0 0 1] oriented magnetite thin films grown on MgO substrates. A high image quality of the Kikuchi patterns was achieved enabling multi-phase scans. Several types of magnetite thin films were analyzed; one as-grown and the others after different annealing steps in oxygen atmosphere. From the EBSD mappings, we learn that the optimum orientation in [0 0 1]-direction is not yet achieved for the as-grown sample, but develops upon oxygen treatment. Furthermore, the distribution of misorientation angles within the investigated area (=1 grain) is found to change during the annealing steps. After 3 min of annealing, most of the misorientations around 30°-40° have vanished, and some islands with high misorientation angles remain, which may play a role as antiferromagnetic pinning centers.

  13. Investigation of microstructure of bulk Ni 2MnGa alloy by means of electron backscatter diffraction analysis

    Science.gov (United States)

    Koblischka-Veneva, A.; Gachot, C.; Leibenguth, P.; Mücklich, F.

    2007-09-01

    The microstructure of bulk samples of the shape memory alloy Ni 2MnGa is evaluated by means of electron backscatter diffraction (EBSD). The crystallographic orientation of individual grains can be determined with a high spatial resolution using an automated recording of Kikuchi patterns. The obtained data are presented in form of image quality (IQ) and orientation maps, pole figures and orientation distribution functions. Local EBSD maps and pole figures reveal details about the orientation of the twin structure. The twin structure is clearly resolved within the EBSD mappings; the matrix is oriented in [1 0 0] direction and there is a 90° misorientation to the neighboring twin. Furthermore, pole figures obtained by EBSD are compared to those determined by means of X-ray texture analysis. Therefore, the EBSD measurements give information not accessible to the X-ray pole figure analysis.

  14. Energy and angular distributions of backscattered electrons from collisions of 5 keV electrons with thick Al, Ti, Ag, W and Pt targets

    Indian Academy of Sciences (India)

    R K Yadav; R Shanker

    2007-03-01

    The energy and angular distributions of backscattered electrons produced under the impact of 5 keV electrons with thick Al, Ti, Ag, W and Pt targets are measured. The energy range of backscattered electrons is considered between B = 50 eV and 5000 eV. The angle of incidence α and take-off angle are chosen to have values = 0° and 10° and = 100°, 110° and 120° respectively. The measured energy spectra are compared with the available theoretical models for = 0° and 10°. The elastic peak intensity of backscattered electrons is found to be a function of angle of incidence, take-off angle and atomic number of the target material. The considered theories are reasonably in good agreement with experiment for the energy spectra of the backscattered electrons having their reduced energies (= B/0) in the range of 0.20 to 1.00.

  15. Linear and nonlinear ultrasonic imaging of tight crack surface with backscattered transverse wave

    International Nuclear Information System (INIS)

    Focusing ultrasonic beams of the mode-converted transverse wave at every point on cracked surfaces, and receiving the backscattered wave signal from those points, we have imaged the tight crack surfaces themselves with a conventional C-scan imaging system. The validity of the technique is confirmed by FEM analyses of scattered wave propagation. The proposed ultrasonic imaging technique was applied to nearly closed fatigue cracks and stress corrosion cracking of stainless steel. In addition to linear ultrasonic imaging, we also visualized higher harmonic amplitude scattered by these crack surfaces by using a high-powered burst wave pulser and bandpass filters. By comparing linear images with higher harmonic images, we can estimate the gap width of the tight cracks.

  16. Validation of neutron texture data on GEM at ISIS using electron backscattered diffraction

    Science.gov (United States)

    Davies, Peter; Kockelmann, Winfried; Wynne, Brad; Eccleston, Roger; Hutchinson, Bevis; Rainforth, W. Mark

    2008-03-01

    The high solid angular coverage of the general materials (GEM) diffractometer at the ISIS pulsed neutron source located at the UK Rutherford Appleton Laboratory offers the capability of obtaining quantitative bulk crystallographic texture data in a 'single shot' within a matter of minutes. This enables the possibility of in situ texture measurements to be made as a function of temperature to monitor and quantify texture changes during phase transformation or microstructure restoration processes like recrystallization. The purpose of this paper is to determine the quality of the texture data produced from GEM in order to define a level of confidence for subsequent texture model validation. This has been achieved by comparing textures of sections of a 200 mm diameter titanium alloy billet using data obtained from GEM with data obtained using electron backscattered diffraction (EBSD). In both cases, the data were obtained at room temperature. EBSD, unlike time-of-flight neutron diffraction analysis, obtains texture data directly from orientation measurements via backscattered Kikuchi patterns in the scanning electron microscope. In all analysed locations, both methods show near-identical textures, with regard to both the general orientation distributions and the levels of intensity of the distributions. This shows that the GEM diffractometer is capable of accurately determining bulk textures in a single shot, thus confirming its suitability for in situ high temperature experiments.

  17. Analytical studies of a backscatter x-ray imaging landmine detection system

    Science.gov (United States)

    Keshavmurthy, Shyam P.; Dugan, Edward T.; Wehlburg, Joseph C.; Jacobs, Alan M.

    1996-05-01

    The Compton Backscatter Imaging (CBI) technique has been applied successfully to detect buried plastic anti-tank landmines. The images acquired by a CBI system are often cluttered by surface features. Additionally, some buried objects give the same response as the plastic landmines. The landmine detection can be successful only when the detection system is capable of distinguishing between surface features and the mine-like objects. This can be accomplished by designing detectors that differentiate between the surface features and the buried objects. An understanding of the physical phenomena underlining the CB image formation helps us to design these detectors. To study the physics of the Compton backscattering, the photon transport in a CBI system is simulated using Monte-Carlo calculations with the generalized particle transport program MCNP. The photon tracks are graphically displayed using a visualization program SABRINA. On the basis of the results from these Monte-Carlo analyses, a four-detector system has been designed. This detector design utilizes the unique nature of various collision components of the scattered photons to generate separate images of buried objects and surface features. The success of this detector design is demonstrated through a series of analytically generated images. The results of the experimental measurements that validate these analytical predictions are brought out in a separate paper to be presented in this conference.

  18. Conversion electron surface imaging

    CERN Document Server

    Irwin, G M; Wehner, A

    1999-01-01

    A method of imaging the Moessbauer absorption over the surface of a sample based on counting conversion electrons emitted from the surface following resonant absorption of gamma radiation is described. This Conversion Electron Surface Imaging (CESI) method is somewhat analogous to Magnetic Resonance Imaging (MRI), particularly chemical shift imaging, and similar tomographic reconstruction techniques are involved in extracting the image. The theory behind the technique and a prototype device is described, as well as the results of proof-of-principle experiments which demonstrate the function of the device. Eventually this same prototype device will be part of a system to determine the spatial variation of the Moessbauer spectrum over the surface of a sample. Applications include imaging of variations of surface properties of steels and other iron containing alloys, as well as other surfaces over which sup 5 sup 7 Fe has been deposited.

  19. Mobile x-ray backscatter imaging system for inspection of vehicles

    Science.gov (United States)

    Swift, Roderick D.

    1997-02-01

    A mobile, rapid-deployment, x-ray system for the inspection of vehicles and freight containers has been developed and delivered in a prototype configuration. The system is based on 450 kV flying-spot x-ray beam technology originally developed for inspection of commercial vehicles at fixed- site border crossings and ports. The fixed-site system includes both transmission and Compton backscatter imaging capabilities. The prototype mobile system employs backscatter imaging only, which allowed it to be brought into service sooner and at lower cost, while still achieving most of the functionality and detection capabilities of a full system. Work is in progress to incorporate transmission imaging. Both the primary radiation dose and the environmental dose due to leakage and scatter are low. Measured primary and secondary radiation exposure rates are presented. The prototype system was configured and certified as a 'cabinet' x-ray system. The pros and cons of this certification compared to alternative 'industrial' certification is discussed. The mobile vehicle/ cargo inspection system is typically deployed and operated by a crew of three. Deployment requires about 10 minutes after its arrival on-site. During acquisition of scan data, a slow-speed hydraulic drive system moves the inspection system past the inspected object at a speed of 6 inches per second. Smaller vehicles (less than about 6 feet in height) can be scanned in a single pass for each side; taller vehicles require multiple scans for full coverage. Sample backscatter images obtained during system tests are presented.

  20. Characterization of the energy response and backscatter contribution for two electronic personal dosimeter models.

    Science.gov (United States)

    Meier, Joseph; Kappadath, S Cheenu

    2015-11-08

    We characterized the energy response of personal dose equivalent (Hp(10) in mrem) and the contribution of backscatter to the readings of two electronic personal dosimeter (EPD) models with radionuclides commonly used in a nuclear medicine clinic. The EPD models characterized were the RADOS RAD-60R, and the SAIC PD-10i. The experimental setup and calculation of EPD energy response was based on ANSI/HPS N13.11-2009. Fifteen RAD-60R and 2 PD-10i units were irradiated using (99m)Tc, (131)I, and (18)F radionuclides with emission energies at 140 keV, 364 keV, and 511 keV, respectively. At each energy, the EPDs output in Hp(10) [mrem] were recorded with 15 inch thick PMMA to simulate backscatter form the torso. Simultaneous free-in-air exposure rate measurements were also performed using two Victoreen ionization survey meters to calculate the expected EPD Hp(10) values per ANSI/HPS N13.11-2009. The energy response was calculated by taking the ratio of the EPD Hp(10) readings with the expected Hp(10) readings and a two-tailed z-test was used to determine the significance of the ratio deviating away from unity. The contribution from backscatter was calculated by taking the ratio of the EPD Hp(10) readings with and without backscatter material. A paired, two-tailed t-test was used to determine the significance of change in EPD Hp(10) readings. The RAD-60R mean energy response at 140 keV was 0.85, and agreed to within 5% and 11% at 364 and 511 keV, respectively. The PD-10i mean energy response at 140 keV was 1.20, and agreed to within 5% at 364 and 511 keV, respectively. On average, in the presence of acrylic, RAD-60R values increased by 32%, 12%, and 14%, at 140, 364, and 511 keV, respectively; all increases were statistically significant. The PD-10i increased by 25%, 19%, and 10% at 140 keV, 364 keV, and 511 keV, respectively; however, only the 140 keV measurement was statistically significant. Although both EPD models performed within the manufacturers' specifications of

  1. Simulation study of x-ray backscatter imaging of pressure-plate improvised explosive devices

    Science.gov (United States)

    van den Heuvel, Johan; Fiore, Franco

    2012-06-01

    Improvised Explosive Devices (IEDs) triggered by pressure-plates are a serious threat in current theatres of operation. X-ray backscatter imaging (XBI) is a potential method for detecting buried pressure-plates. Monte-Carlo simulation code was developed in-house and has been used to study the potential of XBI for pressure-plate detection. It is shown that pressure-plates can be detected at depths up to 7 cm with high photon energies of 350 keV with reasonable speeds of 1 to 10 km/h. However, spatial resolution is relatively low due to multiple scattering.

  2. Electron imaging with an EBSD detector

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Stuart I., E-mail: stuart.wright@ametek.com [EDAX, 392 East 12300 South, Suite H, Draper, UT 84020 (United States); Nowell, Matthew M. [EDAX, 392 East 12300 South, Suite H, Draper, UT 84020 (United States); Kloe, René de [EDAX, Ringbaan Noord 103, 5046 AA Tilburg (Netherlands); Camus, Patrick; Rampton, Travis [EDAX, 91 McKee Drive, Mahwah, NJ 07430 (United States)

    2015-01-15

    Electron Backscatter Diffraction (EBSD) has proven to be a useful tool for characterizing the crystallographic orientation aspects of microstructures at length scales ranging from tens of nanometers to millimeters in the scanning electron microscope (SEM). With the advent of high-speed digital cameras for EBSD use, it has become practical to use the EBSD detector as an imaging device similar to a backscatter (or forward-scatter) detector. Using the EBSD detector in this manner enables images exhibiting topographic, atomic density and orientation contrast to be obtained at rates similar to slow scanning in the conventional SEM manner. The high-speed acquisition is achieved through extreme binning of the camera—enough to result in a 5×5 pixel pattern. At such high binning, the captured patterns are not suitable for indexing. However, no indexing is required for using the detector as an imaging device. Rather, a 5×5 array of images is formed by essentially using each pixel in the 5×5 pixel pattern as an individual scattered electron detector. The images can also be formed at traditional EBSD scanning rates by recording the image data during a scan or can also be formed through post-processing of patterns recorded at each point in the scan. Such images lend themselves to correlative analysis of image data with the usual orientation data provided by and with chemical data obtained simultaneously via X-Ray Energy Dispersive Spectroscopy (XEDS). - Highlights: • The EBSD detector can be used as a set of multiple electron scattering detectors for microstructural imaging. • Extreme binning enables the use of the EBSD detector as an imaging detector with image collection times similar to slow scan SEM imaging. • Using an EBSD detector as an imaging detector provides images showing topographic, atomic density and orientation contrast or a mix of all three. • These images can collect prior to performing a scan, during a scan or through post-processing of patterns

  3. Lead foil in dental X-ray film: Backscattering rejection or image intensifier?

    Energy Technology Data Exchange (ETDEWEB)

    Hönnicke, M.G., E-mail: marcelo.honnicke@unila.edu.br [Universidade Federal da Integração Latino-Americana, Foz do Iguaçu (Brazil); Delben, G.J. [Faculdade de Tecnologia Tupy, Curitiba (Brazil); Godoi, W.C. [Universidade Tecnológica Federal do Paraná, Curitiba (Brazil); Swinka-Filho, V. [Instituto de Tecnologia para o Desenvolvimento – LACTEC, Curitiba (Brazil)

    2014-11-01

    Dental X-ray films are still largely used due to sterilization issues, simplicity and, mainly, economic reasons. These films almost always are double coated (double emulsion) and have a lead foil in contact with the film for X-ray backscattering rejection. Herein we explore the use of the lead foil as an image intensifier. In these studies, spatial resolution was investigated when images were acquired on the dental X-ray films with and without the lead foil. Also, the lead foil was subjected to atomic analysis (fluorescent measurements) and structure analysis (X-ray diffraction). We determined that the use of the lead foil reduces the exposure time, however, does not affect the spatial resolution on the acquired images. This suggests that the fluorescent radiation spread is smaller than the grain sizes of the dental X-ray films.

  4. Lead foil in dental X-ray film: Backscattering rejection or image intensifier?

    International Nuclear Information System (INIS)

    Dental X-ray films are still largely used due to sterilization issues, simplicity and, mainly, economic reasons. These films almost always are double coated (double emulsion) and have a lead foil in contact with the film for X-ray backscattering rejection. Herein we explore the use of the lead foil as an image intensifier. In these studies, spatial resolution was investigated when images were acquired on the dental X-ray films with and without the lead foil. Also, the lead foil was subjected to atomic analysis (fluorescent measurements) and structure analysis (X-ray diffraction). We determined that the use of the lead foil reduces the exposure time, however, does not affect the spatial resolution on the acquired images. This suggests that the fluorescent radiation spread is smaller than the grain sizes of the dental X-ray films

  5. Research on application of CNN in Compton back-scattering image processing

    International Nuclear Information System (INIS)

    A cellular neural network (CNN) is a large-scale nonlinear analog circuit suitable for real-time signal and image processing. CNN can be used for high-speed parallel computation and is easy to be translated into a VLSI implementation. This paper presents one new approach for Compton back-scattering (CBS) image filter and segmentation using CNN. Furthermore presents one new way for eliminating isolated point on CNN and morphologic method. CNN Some practical results are presented and briefly discussed, which demonstrates the successful operation of the proposed algorithm. Those new approaches is very affordable to parallelism and analog VLSI implementation, which allowing the CBS image processing to be performed in real-time. (authors)

  6. Notes on representing grain size distributions obtained by electron backscatter diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Toth, Laszlo S., E-mail: laszlo.metz@univ-lorraine.fr [Laboratoire d' Etude des Microstructures et de Mécanique des Matériaux (LEM3), UMR 7239, CNRS/Université de Lorraine, F-57045 Metz (France); Laboratory of Excellence on Design of Alloy Metals for low-mAss Structures (DAMAS), Université de Lorraine (France); Biswas, Somjeet, E-mail: somjeetbiswas@gmail.com [Laboratory of Excellence on Design of Alloy Metals for low-mAss Structures (DAMAS), Université de Lorraine (France); Gu, Chengfan, E-mail: chengfan.gu@unsw.edu.au [School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052 (Australia); Beausir, Benoit, E-mail: benoit.beausir@univ-lorraine.fr [Laboratoire d' Etude des Microstructures et de Mécanique des Matériaux (LEM3), UMR 7239, CNRS/Université de Lorraine, F-57045 Metz (France); Laboratory of Excellence on Design of Alloy Metals for low-mAss Structures (DAMAS), Université de Lorraine (France)

    2013-10-15

    Grain size distributions measured by electron backscatter diffraction are commonly represented by histograms using either number or area fraction definitions. It is shown here that they should be presented in forms of density distribution functions for direct quantitative comparisons between different measurements. Here we make an interpretation of the frequently seen parabolic tales of the area distributions of bimodal grain structures and a transformation formula between the two distributions are given in this paper. - Highlights: • Grain size distributions are represented by density functions. • The parabolic tales corresponds to equal number of grains in a bin of the histogram. • A simple transformation formula is given to number and area weighed distributions. • The particularities of uniform and lognormal distributions are examined.

  7. Spectral Ellipsometry and Electron Backscatter Diffraction Analyses of Silicon Surfaces Implanted with Silver Ions

    Science.gov (United States)

    Bazarov, V. V.; Nuzhdin, V. I.; Valeev, V. F.; Vorobev, V. V.; Osin, Yu. N.; Stepanov, A. L.

    2016-03-01

    Amorphous silicon (a-Si) produced on surfaces of single-crystal substrates (c-Si) by low-energy low-dose implantation of silver ions is studied by spectral ellipsometry and electron backscatter diffraction. Implantation was done with an ion energy of 30 keV at a constant ion beam current density of 2 μA/cm2 and doses of 6.24·1012-1.25·1016 ions/cm2 on room temperature substrate targets. Irradiation was carried out with a current density of 0.1-5 μA/cm2 for implantation doses of 6.24·1013 and 1.87·1014 ions/cm2. It was found that spectral ellipsometry is an accurate andreliable method for monitoring low-dose ion implantation processes.

  8. Electron backscatter diffraction study of polycrystalline YBa 2Cu 3O 7- δ ceramics

    Science.gov (United States)

    Koblischka-Veneva, Anjela; Koblischka, Michael R.; Simon, Petra; Mücklich, Frank; Murakami, Masato

    2002-11-01

    The electron backscatter diffraction (EBSD) technique was applied to polycrystalline YBa 2Cu 3O 7- δ ceramics. To obtain good quality EBSD Kikuchi patterns on the ceramic superconductors, a new sample polishing route was established. Samples with and without KClO 3-doping were investigated; and the crystallographic orientations of the grains were analyzed using pole figures and EBSD orientation mapping. On the polycrystalline KClO 3-doped YBa 2Cu 3O 7- δ samples we found two major orientations (0 0 1) and (1 0 0) normal to the sample surface, while the undoped sample did not exhibit any orientation maxima. We ascribe this observation to the effect of a liquid phase due to the KClO 3-additive during the preparation process.

  9. Adaptive characterization of recrystallization kinetics in IF steel by electron backscatter diffraction.

    Science.gov (United States)

    Kim, Dong-Kyu; Park, Won-Woong; Lee, Ho Won; Kang, Seong-Hoon; Im, Yong-Taek

    2013-12-01

    In this study, a rigorous methodology for quantifying recrystallization kinetics by electron backscatter diffraction is proposed in order to reduce errors associated with the operator's skill. An adaptive criterion to determine adjustable grain orientation spread depending on the recrystallization stage is proposed to better identify the recrystallized grains in the partially recrystallized microstructure. The proposed method was applied in characterizing the microstructure evolution during annealing of interstitial-free steel cold rolled to low and high true strain levels of 0.7 and 1.6, respectively. The recrystallization kinetics determined by the proposed method was found to be consistent with the standard method of Vickers microhardness. The application of the proposed method to the overall recrystallization stages showed that it can be used for the rigorous characterization of progressive microstructure evolution, especially for the severely deformed material.

  10. Determination of quality parameters in apple `Smoothee Golden Delicious' using backscattering laser imaging

    Science.gov (United States)

    Lafuente, Victoria; Val, Jesús; Urzola, Concha; Negueruela, Ignacio

    2013-11-01

    The objective of this study was to evaluate in `Smoothee Golden Delicious' apples, the use of backscattering images as a non-destructive method to estimate some quality parameters during the ripening process of fruits. In this experiment, 208 apples were collected from an experimental orchard of the Estación Experimental de Aula Dei (CSIC) in Zaragoza (Northeastern, Spain). Backscattering images were kept from samples picked up every 15 days during 7 months until harvest. In the same fruits, soluble solids contents (SSC) and firmness were measured by traditional destructive methods. The light source was a solid state laser diode module emitting at three different spectral bands (670, 785 and 980 nm) PLS calibration methods were used to create the statistical model to predict SSC and firmness. Good results were obtained when PLS calibration was applied to Feret diameter corresponding at different levels of gray. The Rcv2 values were 0.87 for firmness and 0.93 for SSC, which are higher than other reported in the literature for the same commodity.

  11. Three-dimensional electron backscattered diffraction analysis of deformation in MgO micropillars

    Energy Technology Data Exchange (ETDEWEB)

    Korte, S., E-mail: sandra.korte@cantab.net [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Ritter, M. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Jiao, C. [FEI Company, Achtseweg Noord 5, 5651 GG Eindhoven (Netherlands); Midgley, P.A.; Clegg, W.J. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom)

    2011-11-15

    Small-scale testing is extensively used to study the effects of size on plasticity or characterise plastic deformation of brittle materials, where cracking is suppressed on the microscale. Geometrical and experimental constraints have been shown to affect small-scale deformation and efforts are underway to understand these better. However, current analytical techniques tend to possess high resolution in only one or two dimensions, impeding a detailed analysis of the entire deformed volume. Here electron backscattered diffraction in three dimensions is presented as a way of characterising three-dimensional (3-D) deformation at high spatial resolution. It is shown that, by reconstruction of compressed and then successively sliced and indexed MgO micropillars, this 3-D technique yields information complementary to {mu}-Laue diffraction or electron microscopy, allowing a correlation of experimental artefacts and the distribution of plasticity. In addition, deformation features which are difficult to visualise by standard scanning electron microscopy are easily detected, for example where only small surface traces are produced or minimal plastic strain can be introduced before failure in brittle materials.

  12. Design of a proton-electron beam overlap monitor for the new RHIC electron lens, based on detecting energetic backscattered electrons

    Energy Technology Data Exchange (ETDEWEB)

    Thieberger T.; Beebe, E.; Fischer, W.; Gassner, D.; Gu, X.; Hamdi, K.; Hock, J.; Minty, M.; Miller, T.; Montag, C.; Pikin, A.

    2012-04-15

    The optimal performance of the two electron lenses that are being implemented for high intensity polarized proton operation of RHIC requires excellent collinearity of the {approx}0.3 mm RMS wide electron beams with the proton bunch trajectories over the {approx}2m interaction lengths. The main beam overlap diagnostic tool will make use of electrons backscattered in close encounters with the relativistic protons. These electrons will spiral along the electron guiding magnetic field and will be detected in a plastic scintillator located close to the electron gun. A fraction of these electrons will have energies high enough to emerge from the vacuum chamber through a thin window thus simplifying the design and operation of the detector. The intensity of the detected electrons provides a measure of the overlap between the e- and the opposing proton beams. Joint electron arrival time and energy discrimination may be used additionally to gain some longitudinal position information with a single detector per lens.

  13. Imaging near-surface heterogeneities by natural migration of backscattered surface waves

    KAUST Repository

    AlTheyab, Abdullah

    2016-02-01

    We present a migration method that does not require a velocity model to migrate backscattered surface waves to their projected locations on the surface. This migration method, denoted as natural migration, uses recorded Green\\'s functions along the surface instead of simulated Green\\'s functions. The key assumptions are that the scattering bodies are within the depth interrogated by the surface waves, and the Green\\'s functions are recorded with dense receiver sampling along the free surface. This natural migration takes into account all orders of multiples, mode conversions and non-linear effects of surface waves in the data. The natural imaging formulae are derived for both active source and ambient-noise data, and computer simulations show that natural migration can effectively image near-surface heterogeneities with typical ambient-noise sources and geophone distributions.

  14. The Simulation of AN Imaging Gamma-Ray Compton Backscattering Device Using GEANT4

    Science.gov (United States)

    Flechas, D.; Sarmiento, L. G.; Cristancho, F.; Fajardo, E.

    2014-02-01

    A gamma-backscattering imaging device dubbed Compton Camera, developed at GSI (Darmstadt, Germany) and modified and studied at the Nuclear Physics Group of the National University of Colombia in Bogotá, uses the back-to-back emission of two gamma rays in the positron annihilation to construct a bidimensional image that represents the distribution of matter in the field-of-view of the camera. This imaging capability can be used in a host of different situations, for example, to identify and study deposition and structural defects, and to help locating concealed objects, to name just two cases. In order to increase the understanding of the response of the Compton Camera and, in particular, its image formation process, and to assist in the data analysis, a simulation of the camera was developed using the GEANT4 simulation toolkit. In this work, the images resulting from different experimental conditions are shown. The simulated images and their comparison with the experimental ones already suggest methods to improve the present experimental device

  15. Crystallographic Characteristic of Intermetallic Compounds in Al-Si-Mg Casting Alloys Using Electron Backscatter Diffraction

    Institute of Scientific and Technical Information of China (English)

    ZOU Yongzhi; XU Zhengbing; HE Juan; ZENG Jianmin

    2010-01-01

    The Al-Si-Mg alloy which can be strengthened by heat treatment is widely applied to the key components of aerospace and aeronautics. Iron-rich intermetallic compounds are well known to be strongly influential on mechanical properties in Al-Si-Mg alloys. But intermetallic compounds in cast Al-Si-Mg alloy intermetallics are often misidentified in previous metallurgical studies. It was described as many different compounds, such as AlFeSi, Al8Fe2Si, Al5(Fe, Mn)3Si2 and so on. For the purpose of solving this problem, the intermetallic compounds in cast Al-Si alloys containing 0.5% Mg were investigated in this study. The iron-rich compounds in Al-Si-Mg casting alloys were characterized by optical microscope(OM), scanning electron microscope(SEM), energy dispersive X-ray spectrometer(EDS), electron backscatter diffraction(EBSD) and X-ray powder diffraction(XRD). The electron backscatter diffraction patterns were used to assess the crystallographic characteristics of intermetallic compounds. The compound which contains Fe/Mg-rich particles with coarse morphologies was Al8FeMg3Si6 in the alloy by using EBSD. The compound belongs to hexagonal system, space group P2m, with the lattice parameter a=0.662 nm, c=0.792 nm. The β-phase is indexed as tetragonal Al3FeSi2, space group I4/mcm, a=0.607 nm and c=0.950 nm. The XRD data indicate that Al8FeMg3Si6 and Al3FeSi2 are present in the microstructure of Al-7Si-Mg alloy, which confirms the identification result of EBSD. The present study identified the iron-rich compound in Al-Si-Mg alloy, which provides a reliable method to identify the intermetallic compounds in short time in Al-Si-Mg alloy. Study results are helpful for identification of complex compounds in alloys.

  16. On the optimum resolution of transmission-electron backscattered diffraction (t-EBSD).

    Science.gov (United States)

    van Bremen, R; Ribas Gomes, D; de Jeer, L T H; Ocelík, V; De Hosson, J Th M

    2016-01-01

    The work presented aims at determining the optimum physical resolution of the transmission-electron backscattered diffraction (t-EBSD) technique. The resolution depends critically on intrinsic factors such as the density, atomic number and thickness of the specimen but also on the extrinsic experimental set-up of the electron beam voltage, specimen tilt and detector position. In the present study, the so-called physical resolution of a typical t-EBSD set-up was determined with the use of Monte Carlo simulations and confronted to experimental findings. In the case of a thin Au film of 20 nm, the best resolution obtained was 9 nm whereas for a 100 nm Au film the best resolution was 66 nm. The precise dependence of resolution on thickness was found to vary differently depending on the specific elements involved. This means that the resolution of each specimen should be determined individually. Experimentally the median probe size of the t-EBSD for a 140 nm thick AuAg specimen was measured to be 87 nm. The first and third quartiles of the probe size measurements were found to be 60 nm and 118 nm. Simulation of this specimen resulted in a resolution of 94 nm which fits between these quartiles.

  17. A flying spot X-ray system for Compton backscatter imaging.

    Science.gov (United States)

    Herr, M D; McInerney, J J; Lamser, D G; Copenhaver, G L

    1994-01-01

    A Compton X-ray backscatter imaging (CBI) system using a single detector and a mechanically rastered "flying spot" X-ray beam has been designed, built, and tested. While retaining the essential noninvasive imaging capability of previous multiple detector CBI devices, this single detector system incorporates several advances over earlier CBI devices: more efficient detection of scattered X-rays, reduced X-ray exposure, and a simplified scan protocol more suitable for use with humans. This new CBI system also has specific design features to permit automating data acquisition from multiple two-dimensional image planes for integration into a 3D dynamic surface image. A simulated multislice scan study of a human thorax phantom provided X-ray dosimetry data verifying a very low X-ray dose (~50 mrem) delivered by this imaging device. Validation experiments with mechanical models show that surface displacement at typical heart beat frequencies can be measured to the nearest 0.1 mm (SD). PMID:18218521

  18. Tackling pseudosymmetry problems in electron backscatter diffraction (EBSD) analyses of perovskite structures

    Science.gov (United States)

    Mariani, Elisabetta; Kaercher, Pamela; Mecklenburgh, Julian; Wheeler, John

    2016-04-01

    Perovskite minerals form an important mineral group that has applications in Earth science and emerging alternative energy technologies, however crystallographic quantification of these minerals with electron backscatter diffraction (EBSD) is not accurate due to pseudosymmetry problems. The silicate perovskite Bridgmanite, (Mg,Fe)SiO3, is understood to be the dominant phase in the Earth's lower mantle. Gaining insight into its physical and rheological properties is therefore vital to understand the dynamics of the Earth's deep interior. Rock deformation experiments on analogue perovskite phases, for example (Ca,Sr)TiO3, combined with quantitative microstructural analyses of the recovered samples by EBSD, yield datasets that can reveal what deformation mechanisms may dominate the flow of perovskite in the lower mantle. Additionally, perovskite structures have important technological applications as new, suitable cathodes for the operation of more efficient and environmentally-friendly solid oxide fuel cells (SOFC). In recent years they have also been recognised as a potential substitute for silicon in the next generation of photovoltaic cells for the construction of economic and energy efficient solar panels. EBSD has the potential to be a valuable tool for the study of crystal orientations achieved in perovskite substrates as crystal alignment has a direct control on the properties of these materials. However, perovskite structures currently present us with challenges during the automated indexing of Kikuchi bands in electron backscatter diffraction patterns (EBSPs). Such challenges are represented by the pseudosymmetric character of perovskites, where atoms are subtly displaced (0.005 nm to 0.05 nm) from their higher symmetry positions. In orthorhombic Pbnm perovskites, for example, pseudosymmetry may be evaluated from the c/a unit cell parameter ratio, which is very close to 1. Two main types of distortions from the higher symmetry structure are recognised: a

  19. Determination of the easy axes of small ferromagnetic precipitates in a bulk material by combined magnetic force microscopy and electron backscatter diffraction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Batista, L., E-mail: leonardo.batista@izfp.fraunhofer.de [Fraunhofer Institute for Non-destructive Testing (IZFP), Campus E3 1, 66123 Saarbrücken (Germany); Rabe, U. [Fraunhofer Institute for Non-destructive Testing (IZFP), Campus E3 1, 66123 Saarbrücken (Germany); University of the Saarland, LZPQ, 66123 Saarbrücken (Germany); Hirsekorn, S. [Fraunhofer Institute for Non-destructive Testing (IZFP), Campus E3 1, 66123 Saarbrücken (Germany)

    2014-11-15

    A method to determine the magnetic easy axes of micro- and nanoscopic ferromagnetic precipitates embedded in a bulk material is proposed and applied to globular cementite (Fe{sub 3}C) embedded in a ferrite matrix. The method combines magnetic force microscopy (MFM) with electron backscattered diffraction (EBSD) measurements. Magnetic domain structures in globular and in lamellar cementite precipitates in unalloyed pearlitic steels were imaged using MFM. The domain structure of the precipitates was analyzed in dependency of their size, shape and crystallographic orientation. It was found that the magnetic moments of the cementite precipitates are highly geared to their crystalline axes. The combined MFM and EBSD studies allow the conclusion that the cementite easy direction of magnetization is the long [010] axis. For fine lamellae cementite the determination of their crystallographic orientations using electron diffraction techniques is very difficult. With the previous knowledge of the behavior of the domain structure in globular cementite, the crystalline orientations of the fine lamellae cementite can be estimated by simply observing the magnetic microstructures and the topographic profiles. - Highlights: • We develop a method to determine the easy axes of nanoscopic ferromagnetic precipitates in a matrix. • We combine the magnetic force microscopy and the electron backscatter diffraction techniques. • Globular and lamellar cementite (Fe{sub 3}C) precipitates are taken as examples. • MFM images revealed different orientations of the magnetic moments in cementite. • The cementite easy direction of magnetization is the long [010] axis.

  20. Determination of the easy axes of small ferromagnetic precipitates in a bulk material by combined magnetic force microscopy and electron backscatter diffraction techniques

    International Nuclear Information System (INIS)

    A method to determine the magnetic easy axes of micro- and nanoscopic ferromagnetic precipitates embedded in a bulk material is proposed and applied to globular cementite (Fe3C) embedded in a ferrite matrix. The method combines magnetic force microscopy (MFM) with electron backscattered diffraction (EBSD) measurements. Magnetic domain structures in globular and in lamellar cementite precipitates in unalloyed pearlitic steels were imaged using MFM. The domain structure of the precipitates was analyzed in dependency of their size, shape and crystallographic orientation. It was found that the magnetic moments of the cementite precipitates are highly geared to their crystalline axes. The combined MFM and EBSD studies allow the conclusion that the cementite easy direction of magnetization is the long [010] axis. For fine lamellae cementite the determination of their crystallographic orientations using electron diffraction techniques is very difficult. With the previous knowledge of the behavior of the domain structure in globular cementite, the crystalline orientations of the fine lamellae cementite can be estimated by simply observing the magnetic microstructures and the topographic profiles. - Highlights: • We develop a method to determine the easy axes of nanoscopic ferromagnetic precipitates in a matrix. • We combine the magnetic force microscopy and the electron backscatter diffraction techniques. • Globular and lamellar cementite (Fe3C) precipitates are taken as examples. • MFM images revealed different orientations of the magnetic moments in cementite. • The cementite easy direction of magnetization is the long [010] axis

  1. An electron backscatter diffraction investigation of crystallographic orientations of embedded nanoparticles within melt-textured YBCO high temperature superconductors

    Science.gov (United States)

    Koblischka-Veneva, A.; Koblischka, M. R.; Babu, N. Hari; Cardwell, D. A.; Shlyk, L.; Krabbes, G.

    2006-07-01

    Microstructures of melt-textured YBCO samples with embedded nanosized particles of Y2BaCuO5 (Y-211) and Y2Ba4CuMOx (M-2411 with M = U,Zr) are analysed by means of electron backscatter diffraction (EBSD). With the recent developments of the EBSD technique, we can directly measure the crystallographic orientation of the embedded nanoparticles, employing a spatial resolution of about 40 nm. The high image quality of the Kikuchi patterns allows true three-phase (YBCO, Y-211 and M-2411) scans to be performed. The Y-211 particles do not exhibit any preferred orientation, even if their size is considerably reduced, to the 100 nm range. The size reduction reduces the negative influence of the Y-211 particles on the YBCO matrix, however. U-2411 particles, which are formed during the processing stage, do not show any orientation, and with increasing concentration, some texture develops. In contrast to this, embedded Zr-2411 particles are fully oriented in the (001) orientation according to the surrounding superconducting matrix.

  2. Assessing strain mapping by electron backscatter diffraction and confocal Raman microscopy using wedge-indented Si.

    Science.gov (United States)

    Friedman, Lawrence H; Vaudin, Mark D; Stranick, Stephan J; Stan, Gheorghe; Gerbig, Yvonne B; Osborn, William; Cook, Robert F

    2016-04-01

    The accuracy of electron backscatter diffraction (EBSD) and confocal Raman microscopy (CRM) for small-scale strain mapping are assessed using the multi-axial strain field surrounding a wedge indentation in Si as a test vehicle. The strain field is modeled using finite element analysis (FEA) that is adapted to the near-indentation surface profile measured by atomic force microscopy (AFM). The assessment consists of (1) direct experimental comparisons of strain and deformation and (2) comparisons in which the modeled strain field is used as an intermediate step. Direct experimental methods (1) consist of comparisons of surface elevation and gradient measured by AFM and EBSD and of Raman shifts measured and predicted by CRM and EBSD, respectively. Comparisons that utilize the combined FEA-AFM model (2) consist of predictions of distortion, strain, and rotation for comparison with EBSD measurements and predictions of Raman shift for comparison with CRM measurements. For both EBSD and CRM, convolution of measurements in depth-varying strain fields is considered. The interconnected comparisons suggest that EBSD was able to provide an accurate assessment of the wedge indentation deformation field to within the precision of the measurements, approximately 2×10(-4) in strain. CRM was similarly precise, but was limited in accuracy to several times this value. PMID:26939030

  3. Position-dependent texture analysis of melt-textured YBCO by means of electron backscatter diffraction

    Science.gov (United States)

    Koblischka-Veneva, A.; Koblischka, M. R.; Ogasawara, K.; Murakami, M.

    2003-10-01

    The texture and phase distribution of melt-textured YBa 2Cu 3O x (YBCO) was studied by means of automated electron backscatter diffraction (EBSD) analysis as a function of the position in the bulk pellet of 4 cm diameter. A total of five samples was cut from the pellet; four samples from the surface of the bulk with different distances to the seed crystal, and one cut in vertical direction in the middle of the pellet. The melt-textured YBCO samples require a two-phase analysis to be performed, so a high surface quality is necessary to enable an automated EBSD scan. Good quality Kikuchi patterns are obtained from both the 1 2 3 and 2 1 1 phases. We found an inhomogeneous distribution of the 2 1 1 particles. Whereas the samples cut from the surface contain a large amount of 2 1 1 particles, in the samples of the vertical direction only traces of 2 1 1 particles are found. Furthermore, we measured the misorientation angle distribution of all samples. The data are presented in form of phase mappings, misorientation distribution functions and pole figures.

  4. Application of electron backscatter diffraction to bulk high-Tc superconductors

    Science.gov (United States)

    Koblischka-Veneva, A.; Koblischka, M. R.; Simon, P.; Mücklich, F.; Murakami, M.

    2002-05-01

    We have successfully obtained electron backscatter diffraction (EBSD) Kikuchi patterns on various bulk high-Tc superconductors (polycrystalline KClO3-doped and undoped YBa2Cu3O7-δ (YBCO), single crystalline YBCO and NdBa2Cu3O7-y) and on YBCO and NdBCO thin films. We have established a sample polishing procedure to obtain intense Kikuchi patterns without an additional carbon coating of the ceramic superconductors. We present Kikuchi patterns, pole figures and orientation maps of the samples. On the polycrystalline KClO3-doped YBCO samples we find two major orientations (001) and (100) normal to the sample surface, while the undoped sample does not exhibit any orientation maxima, which is ascribed to the effect of a liquid phase due to the KClO3-additive during the preparation process. Furthermore, we discuss the future possibilities for the application of the EBSD technique for growing larger, bulk melt-textured samples for applications.

  5. In situ electron backscatter diffraction investigation of recrystallization in a copper wire.

    Science.gov (United States)

    Brisset, François; Helbert, Anne-Laure; Baudin, Thierry

    2013-08-01

    The microstructural evolution of a cold drawn copper wire (reduction area of 38%) during primary recrystallization and grain growth was observed in situ by electron backscatter diffraction. Two thermal treatments were performed, and successive scans were acquired on samples undergoing heating from ambient temperature to a steady state of 200°C or 215°C. During a third in situ annealing, the temperature was continuously increased up to 600°C. Nuclei were observed to grow at the expense of the deformed microstructure. This growth was enhanced by the high stored energy difference between the nuclei and their neighbors (driving energy in recrystallization) and by the presence of high-angle grain boundaries of high mobility. In the early stages of growth, the nuclei twin and the newly created orientations continue to grow to the detriment of the strained copper. At high temperatures, the disappearance of some twins was evidenced by the migration of the incoherent twin boundaries. Thermal grooving of grain boundaries is observed at these high temperatures and affects the high mobile boundaries but tends to preserve the twin boundaries of lower energy. Thus, grooving may contribute to the twin vanishing.

  6. Lateral migration radiography: a new x-ray backscatter imaging technique

    Science.gov (United States)

    Jacobs, Alan M.; Dugan, Edward T.; Brygoo, Stephanie; Ekdahl, Dan; Houssay, Laurent; Su, Zhong

    2002-11-01

    A new Compton backscatter imaging (CBI) technique, described as lateral migration radiography (LMR), has been developed and applied successfully to two difficult diagnostic problems: Detection of buried, plastic landmines, and detection of material flaws which lie close to, and parallel to, a surface, the method is based on image contrast generated by alteration of photon lateral migration relative to the illuminating beam direction. It is extraordinarily sensitive to density and/or atomic number variation along the photon lateral-direction travel paths. In LMR, relevant information-carrying photon detection efficiencies are two to three orders-of-magnitude greater than other CBI techniques such that the electric energy requirement for x-ray generation is only about one joule per acquired image pixel. The resulting small product of pixel illumination dwell time and x-ray generator electric power implies that current, easily accessible technology can be used to fabricate LMR systems with practical usage protocols. Three have been designed and built at the University of Florida: A laboratory device for perfecting buried landmine acquisition; a mobile system for field-demonstrating landmine detection; and, a laboratory system for detection of material defects in small structural parts. The LMR images, acquired in a laboratory landmine detection setting, are so definitive that identification of the mine-type, as well as presence, can be often accomplished. Results of a field test are near-perfect, both in determining buried landmine presence and in lack of false positive response. Images acquired in material flaw detection indicate ability to detect lateral cracks or delaminations with thickness less than 100 microns, as well as corrosion on surfaces between layers of structural sheets. These applications provide evidence of the viability of a new, one-sided x-ray radiography technique which images hidden structures of objects which have here-to-fore been difficult, or

  7. Simulation of emittance dilution in electron storage ring from Compton backscattering

    International Nuclear Information System (INIS)

    A Monte-Carlo simulation of Compton backscattered λL =3.2-μm (EL = .38494 eV) photons from an IR-FEL on 75-MeV electrons in a storage ring yields an RMS electron energy spread of ΔE= 11.9-keV for a sample of 107 single scattering events. Electrons are sampled from a beam of natural energy spread σE = 5.6-keV and damped transverse angle spreads σx = .041-mrad and σy = .052-mrad (100%) coupling, scaled from the 200-MeV BNL XLS compact storage ring. The Compton-scattered X-Rays are generated from an integral of the CM Klein-Nishina cross-section transformed to the lab. A tracking calculation has also been performed in 6-dimensional phase space. Initial electron coordinates are selected randomly from a Gaussian distribution of RMS spreads σxo =.102-mm, σx'o=0.41-mrad, σyo=0.18-mm, σy'o=0.52-mrad, σφo=22-mrad and σEo=6-keV. A sample of 10000 electrons were each following for 40000 turns around the ring through an RF cavity of frf=211.54-MHz and peak voltage Vm=300-keV. Preliminary results indicate that the resulting energy distribution is quite broad with an RMS width of ΔE = 124-keV. The transverse widths are only slightly increased from their original values, i.e. Δx =.106-mm and ΔE=.043 mrad. The scaled energy spread of ΔE∼360-keV for ∼350,000 turns desired in a 10-msec X-Ray angiography exposure is well within the RF bucket used here; even VmEX=.32-keV. The electron energy damping time of τE=379-msec at 75-MeV in an XLS-type ring allows for damping this induced spread and top-off the ring between heart cycles

  8. Simulation of emittance dilution in electron storage ring from Compton backscattering

    International Nuclear Information System (INIS)

    A Monte-Carlo simulation of Compton backscattered κL=3.2-μm photons from an IR-FEL on 75-MeV electrons in a storage ring yields an RMS electron energy spread of ΔE=11.9-keV for a sample of 107 single scattering events. Electrons are sampled from a beam of natural energy spread σE = 5.6-keV and damped transverse angle spreads σx', = .041-mrad and σy' = .052-mrad (100%) coupling, scaled from the 200-MeV BNL XLS compact storage ring. The Compton-scattered X-Rays are generated from an integral of the CM Klein-Nishina cross-section transformed to the lab. A tracking calculation has also been performed in 6-dimensional phase space. Initial electron coordinates are selected randomly from a Gaussian distribution of RMS spreads σxo=.102-mm, σx'o=.041-mrad, σyo=.018-mm, σy'o=.052-mrad, σφo=22-mrad and σEo=6-keV. A sample of 10000 electrons were each following for 40000 turns around the ring through an RF cavity of frf=211.54-MHz and peak voltage Vm=300-keV. Preliminary results indicate that the resulting energy distribution is quite broad with an RMS width of ΔE = 124-keV. The transverse widths are only slightly increased from their original values, i.e. Δx = .106-mm and Δx'=.043 mrad. The scaled energy spread of ΔE ∼ 360-keV for ∼ 350,000 turns desired in a 10-msec X-Ray angiography exposure is well within the RF bucket used here; even Vm Ex=.32-keV. The electron energy damping time of τE=379-msec at 75-MeV in an XLS-type ring allows for damping this induced spread and top-off of the ring between heart cycles

  9. Detector for high-energy photon backscatter

    Science.gov (United States)

    Silver, Michael D.; Erker, Joseph W.; Duncan, Michael Z.; Hartford, Thomas J.; Sivers, E. A.; Hopkinson, James F.

    1993-12-01

    High energy photon backscatter uses pair production to probe deep beneath surfaces with single side accessibility or to image thick, radiographically opaque objects. At the higher photon energies needed to penetrate thick and/or highly attenuating objects, Compton backscatter becomes strongly forward peaked with relatively little backscatter flux. Furthermore, the downward energy shift of the backscattered photon makes it more susceptible to attenuation on its outbound path. Above 1.022 MeV, pair production is possible; at about 10 MeV, pari production crosses over Compton scatter as the dominant x-ray interaction mechanism. The backscattered photons can be hard x rays from the bremsstrahlung of the electrons and positrons or 0.511 MeV photons from the annihilation of the positron. Monte Carlo computer simulations of such a backscatter system were done to characterize the output signals and to optimize a high energy detector design. This paper touches on the physics of high energy backscatter imaging and describes at some length the detector design for tomographic and radiographic imaging.

  10. Compton back-scattering of X-photons from 8 GeV electrons at SPring-8

    CERN Document Server

    Nelyubin, V V; Nakano, T; Wojtsekhowski, B B

    1999-01-01

    The experimental feasibility of using an intensive photon beam at the SPring-8 for producing a high-energy gamma-ray beam is examined. Compton back-scattering of the soft X-photons emitted by an undulator and reflected back by a multi-layer mirror from the electron beam can produce a quasi-monochromatic gamma-ray beam up to an energy very close to 8 GeV. The intensity of the gamma-ray beam in the energy range of 6.6-7.8 GeV has been estimated at 2x10 sup 4 per second. The energy shape and the scattered angle of gamma-rays produced in Compton back-scattering of the soft X-photons from an 8 GeV electron beam are calculated.

  11. Backscattering of Laser Radiation on Ultrarelativistic Electrons in a Transverse Magnetic Field: Evidence of MeV-Scale Photon Interference

    Science.gov (United States)

    Abakumova, E. V.; Achasov, M. N.; Berkaev, D. E.; Kaminsky, V. V.; Muchnoi, N. Yu.; Perevedentsev, E. A.; Pyata, E. E.; Shatunov, Yu. M.

    2013-04-01

    In this Letter we report an observation of interference effects in Compton scattering in the experiment held on the VEPP-2000 collider. Infrared laser radiation was scattered head-on the 990 MeV electrons inside the dipole magnet, where an electron orbit radius is about 140 cm. It was observed that the energy spectrum of backscattered photons, measured by a HPGe detector, differs from that defined by the Klein-Nishina cross section and scattering kinematics of free electrons. The explanation of the effect, proposed in terms of classical electrodynamics, is in agreement with QED calculations.

  12. Direct imaging of turbid media using long-time back-scattered photons, a numerical study

    Energy Technology Data Exchange (ETDEWEB)

    Boulanger, Joan; Liu, Fengshan [Groupe de Recherche en Ingenierie des Procedes et Systemes, Departement des Sciences Appliquees, Universite du Quebec a Chicoutimi, 555 Boulevard de l' Universite, Chicoutimi, PQ, G7H 2B1 (Canada); El Akel, Azad; Charette, Andre [Technologie de la Combustion, Institut de Technologie des Procedes Chimiques et de l' Environnement, Conseil National de Recherche du Canada, 1200 Chemin de Montreal, Ottawa, ON, K1A 0R6 (Canada)

    2006-06-15

    Direct imaging is a convenient way to obtain information on the interior of a semi-transparent turbid material by non-invasive probing using laser beams. The major difficulty is linked to scattering which scrambles the directional information coming from the laser beam. It is found in this paper that the long-term multiple-scattered reflected photons may provide structural information on the inside of a material, which offers an interesting alternative to using information only from un-scattered or least-scattered photons as obtained from current direct imaging set-ups for thin media. Based on some observations on a non-homogeneous three layered 1-D slab irradiated by a laser pulse, a direct probing methodology making use of the long-term back-scattered photons is illustrated to recover inclusions positions in a turbid 2-D medium. First, the numerical model is presented. Second, an extended parametrical study is conducted on 1-D homogeneous and non-homogeneous slabs with different laser pulse durations. It is found that the reflected asymptotic logarithmic slope carries information about the presence of the inclusion and that short laser pulses are not necessary since only the decaying parts of the remanent optical signature is important. Longer laser pulses allow a higher level of energy injection and signal to noise ratio. Third, those observations are used for the probing of a 2-D non-homogeneous phantom. (author)

  13. Evaluation of image-based multibeam sonar backscatter classification for benthic habitat discrimination and mapping at Stanton Banks, UK

    Science.gov (United States)

    McGonigle, Chris; Brown, Craig; Quinn, Rory; Grabowski, Jonathan

    2009-02-01

    In recent years, efforts have increased to develop quantitative, computer-directed methods for segmentation of multibeam (MBES) backscatter data. This study utilises MBES backscatter data acquired at Stanton Banks (UK) and subsequently processed through the QTC-Multiview software environment in a bid to evaluate the program's ability to perform unsupervised classification. Statistical comparison with ground-truth data (grab, stills and video) enabled cross validation of acoustic segmentation and biological assemblages observed at the site. 132 unspecified variables were extracted from user-specified rectangular patches of the backscatter image, reduced to three vectors by PCA, then clustered and classified by the software. Multivariate analyses of ground-truth data were conducted on 75 stills images and 51 grab samples. Video footage coincident with the stills was divided into 30 s segments and coded by dominant substrate and species. Cross tabulation determined the interrelationship between software classifications, multivariate analysis of the biological assemblages and coded video segments. Multiview optimally identified 19 classes using the automated clustering engine. These were revised to 6 habitats a posteriori, using combined analysis of ground-truth data and Multiview data products. These habitats broadly correspond to major physiographic provinces within the region. Multivariate statistical analysis reveals low levels of assemblage similarity (MBES backscatter imagery into acoustic provinces; however a degree of caution is required prior to ascribing ecological significance to these classifications.

  14. Texture analysis of monofilamentary, Ag-sheathed (Pb,Bi) 2Sr 2Ca 2Cu 3O x tapes by electron backscatter diffraction (EBSD)

    Science.gov (United States)

    Koblischka-Veneva, A.; Koblischka, M. R.; Qu, T.; Han, Z.; Mücklich, F.

    2008-02-01

    Using automated orientation imaging, the grain orientations and texture of monofilamentary, Ag-sheathed (Pb,Bi) 2Sr 2Ca 2Cu 3O x (Bi-2223) tape is analysed in detail by means of electron backscatter diffraction (EBSD). The achieved high image quality of the Kikuchi patterns enables multi-phase scans including Bi-2223, Bi 2Sr 2CaCu 2O x, Bi 2Sr 2CuO x, (Sr,Ca) 14Cu 24O 41 and Ag to be performed. Two areas are selected for the EBSD analysis, one close to the silver sheath, the other located in the center of the sample. The grain orientation maps are presented for each phase separately allowing a new insight into the microtexture of Ag-sheathed Bi-2223 tapes. Furthermore, the EBSD analysis provides the possibility for a misorientation angle analysis within each individual phase.

  15. NDE of spacecraft materials using 3D Compton backscatter x-ray imaging

    Science.gov (United States)

    Burke, E. R.; Grubsky, V.; Romanov, V.; Shoemaker, K.

    2016-02-01

    We present the results of testing of the NDE performance of a Compton Imaging Tomography (CIT) system for single-sided, penetrating 3D inspection. The system was recently developed by Physical Optics Corporation (POC) and delivered to NASA for testing and evaluation. The CIT technology is based on 3D structure mapping by collecting the information on density profiles in multiple object cross sections through hard x-ray Compton backscatter imaging. The individual cross sections are processed and fused together in software, generating a 3D map of the density profile of the object which can then be analyzed slice-by-slice in x, y, or z directions. The developed CIT scanner is based on a 200-kV x-ray source, flat-panel x-ray detector (FPD), and apodized x-ray imaging optics. The CIT technology is particularly well suited to the NDE of lightweight aerospace materials, such as the thermal protection system (TPS) ceramic and composite materials, micrometeoroid and orbital debris (MMOD) shielding, spacecraft pressure walls, inflatable habitat structures, composite overwrapped pressure vessels (COPVs), and aluminum honeycomb materials. The current system provides 3D localization of defects and features with field of view 20x12x8 cm3 and spatial resolution ˜2 mm. In this paper, we review several aerospace NDE applications of the CIT technology, with particular emphasis on TPS. Based on the analysis of the testing results, we provide recommendations for continued development on TPS applications that can benefit the most from the unique capabilities of this new NDE technology.

  16. A system of beam energy measurement based on the Compton backscattered laser photons for the VEPP-2000 electron-positron collider

    CERN Document Server

    Abakumova, E V; Berkaev, D E; Kaminsky, V V; Koop, I A; Korol, A A; Koshuba, S V; Krasnov, A A; Muchnoi, N Yu; Perevedentsev, E A; Pyata, E E; Shatunov, P Yu; Shatunov, Yu M; Shwartz, D B

    2013-01-01

    The beam energy measurement system for the VEPP-2000 electron-positron collider is described. The method of Compton backscattering of $CO$ laser photons on the electron beam is used. The relative systematic uncertainty of the beam energy determination is estimated as 6\\cdot10^{-5}. It was obtained through comparison of the results of the beam energy measurements using the Compton backscattering and resonance depolarization methods.

  17. A system of beam energy measurement based on the Compton backscattered laser photons for the VEPP-2000 electron-positron collider

    Science.gov (United States)

    Abakumova, E. V.; Achasov, M. N.; Berkaev, D. E.; Kaminsky, V. V.; Koop, I. A.; Korol, A. A.; Koshuba, S. V.; Krasnov, A. A.; Muchnoi, N. Yu.; Perevedentsev, E. A.; Pyata, E. E.; Shatunov, P. Yu.; Shatunov, Yu. M.; Shwartz, D. B.

    2014-04-01

    The beam energy measurement system for the VEPP-2000 electron-positron collider is described. The method of Compton backscattering of CO laser photons on the electron beam is used. The relative systematic uncertainty of the beam energy determination is estimated as 6×10-5. It was obtained through comparison of the results of the beam energy measurements using the Compton backscattering and resonance depolarization methods.

  18. Polarimetric analysis of radar backscatter from ground-based scatterometers and wheat biomass monitoring with advanced synthetic aperture radar images

    Science.gov (United States)

    He, Lei; Tong, Ling; Li, Yuxia; Chen, Yan; Tan, Longfei; Guo, Caizheng

    2016-04-01

    This article presents an analysis of the scattering measurements for an entire wheat growth cycle by ground-based scatterometers at a frequency of 5.3 GHz. Since wheat ears are related to wheat growth and yield, the radar backscatter of wheat was analyzed at two different periods, i.e., with and without wheat ears. Simultaneously, parameters such as wheat and soil characteristics as well as volume scattering and soil scattering were analyzed for the two periods during the entire growth cycle. Wheat ears have been demonstrated to have a great influence on radar backscatter; therefore, a modified version of water-cloud model used for retrieving biomass should consider the effect of wheat ears. This work presents two retrieval models based on the water-cloud model and adopts the advanced integral equation model to simulate the soil backscatter before the heading stage and the backscatter from the layer under wheat ears after the heading stage. The research results showed that the biomass retrieved from the advanced synthetic aperture radar (ASAR) images to agree well with the data measured in situ after setting the modified water-cloud model for the growth stages with ears. Furthermore, it was concluded that wheat ears should form an essential component of theoretical modeling as they influence the final yield.

  19. A novel lobster-eye imaging system based on Schmidt-type objective for X-ray-backscattering inspection

    Science.gov (United States)

    Xu, Jie; Wang, Xin; Zhan, Qi; Huang, Shengling; Chen, Yifan; Mu, Baozhong

    2016-07-01

    This paper presents a novel lobster-eye imaging system for X-ray-backscattering inspection. The system was designed by modifying the Schmidt geometry into a treble-lens structure in order to reduce the resolution difference between the vertical and horizontal directions, as indicated by ray-tracing simulations. The lobster-eye X-ray imaging system is capable of operating over a wide range of photon energies up to 100 keV. In addition, the optics of the lobster-eye X-ray imaging system was tested to verify that they meet the requirements. X-ray-backscattering imaging experiments were performed in which T-shaped polymethyl-methacrylate objects were imaged by the lobster-eye X-ray imaging system based on both the double-lens and treble-lens Schmidt objectives. The results show similar resolution of the treble-lens Schmidt objective in both the vertical and horizontal directions. Moreover, imaging experiments were performed using a second treble-lens Schmidt objective with higher resolution. The results show that for a field of view of over 200 mm and with a 500 mm object distance, this lobster-eye X-ray imaging system based on a treble-lens Schmidt objective offers a spatial resolution of approximately 3 mm.

  20. Experimental measurement of noise-removal techniques for Compton backscatter imaging systems as applied to the detection of landmines

    Science.gov (United States)

    Wehlburg, Joseph C.; Keshavmurthy, Shyam P.; Dugan, Edward T.; Jacobs, Alan M.

    1996-05-01

    The measurement and removal of noise from images created using lateral migration backscatter radiography (LMBR) a form of Compton backscatter imaging (CBI) is applied to the detection and identification of landmines. The photons that interact with the landmine produce the signal component of interest. The signal is corrupted by both quantum and structured noise. The structured noise is due to photon interaction with non-mine material. Due to the strong response of all detectors to soil surface features and other buried objects, image enhancement methods are essential for landmine identification. A four detector system is used to generate the LMBR/CB images. The inner two detectors are uncollimated and positioned to optimally detect first scattered photons. The outer detectors are collimated to detect photons that have had two or more scatterings. The difference between the collimated and uncollimated detector responses to the different types of landmine image masking phenomena, form the basis of the image enhancement and landmine identification procedures. The surface feature information is obtained by the uncollimated detectors. The collimated detector signal contains information about the surface features as well as the buried objects. Using images from these two sets of detectors the surface objects can be analyzed for possible landmines and then removed. The buried objects can then be resolved. The measurements and image enhancements demonstrate that it is possible to detect 12' plastic landmines at a buried of 3' under simulated battlefield conditions.

  1. Electron backscattering on Si(Li) detectors and determination of the transmission curve of a Mini-Orange Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Guerro, Leonardo, E-mail: leonardo.guerro@unicam.it [Division of Physics, School of Science and Technology, University of Camerino, Camerino (Italy); INFN-Sezione di Perugia (Italy); Blasi, Nives [INFN-Sezione di Milano (Italy); Saltarelli, Alessandro [Division of Physics, School of Science and Technology, University of Camerino, Camerino (Italy); INFN-Sezione di Perugia (Italy)

    2014-03-01

    A detailed electron backscattering analysis in Si(Li) detectors was done in order to evaluate the response function of the Mini-Orange Spectrometer. The analysis was performed via Monte Carlo simulations and by measuring the energy and the angular dependencies without and with the insertion of the Mini-Orange Spectrometer in the detection system, combining data taken with a continuous β{sup −} source ({sup 90}Sr) with those from discrete electron transitions of an electron conversion source ({sup 207}Bi). A simple but accurate method is described to determine the transmission function T(E) of the Mini-Orange. - Highlights: • We analyze electron backscattering in Si(Li) detectors. • We evaluate the response function of a Mini-Orange Spectrometer. • We perform Monte Carlo simulations and measure MOS energy and angular dependencies. • Data are taken with a continuous source combined with a discrete conversion source. • An accurate method is described to determine the transmission of a Mini-Orange.

  2. Scale invariance and scaling law of Thomson backscatter spectra by electron moving in laser-magnetic resonance regime

    CERN Document Server

    Fu, Yi-Jia; Wan, Feng; Sang, Hai-Bo; Xie, Bai-Song

    2016-01-01

    The Thomson scattering spectra by an electron moving in the laser-magnetic resonance acceleration regime are computed numerically and analytically. The dependence of fundamental frequency on the laser intensity and magnetic resonance parameter is examined carefully. By calculating the emission of a single electron in a circularly polarized plane-wave laser field and constant external magnetic field, the scale invariance of the radiation spectra is evident in terms of harmonic orders. The scaling law of backscattered spectra are exhibited remarkably for the laser intensity as well for the initial axial momentum of the electron when the cyclotron frequency of the electron approaches the laser frequency. The results indicate that the magnetic resonance parameter plays an important role on the strength of emission. And the rich features of scattering spectra found may be applicable to the radiation source tunability.

  3. NOAA TIFF Image - 1 m Backscatter Mosaic of Bajo de Cico, Puerto Rico, Project NF-07-06, 2007, UTM 19 NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of Bajo de Cico off the coast of western Puerto Rico, collected using a Kongsberg EM 1002 (95 kHz)...

  4. NOAA TIFF Image - 2 m Backscatter Mosaic of Isla de Mona, Puerto Rico, Project NF-07-06, 2007, UTM 19 NAD83 (NCEI Accession 0131853)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 2 meter resolution backscatter mosaic of the southern coast of Isla de Mona, collected using a Kongsberg EM 1002 (95 kHz) multibeam...

  5. NOAA TIFF Image - 1 m Backscatter Mosaic of Abrir La Sierra Bank, PR (2007) collected using a SeaBat Reson 8124 (200 kHz) multibeam echosounder

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the Abrir La Sierra Bank off the coast of western Puerto Rico, collected using a SeaBat Reson 8124...

  6. NOAA TIFF Image - 1 m Backscatter Mosaic of Abrir La Sierra Bank, PR (2007) collected using a Kongsberg EM 1002 (95 kHz) multibeam echosounder

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the Abrir La Sierra Bank off the coast of western Puerto Rico, collected using a Kongsberg EM 1002...

  7. NOAA TIFF Image- 0.5 meter Backscatter Mosaic of Grammanik Bank - East (St. Thomas), US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of Grammanik Bank, south of St. Thomas, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography Team,...

  8. NOAA TIFF Image- 0.5 meter Backscatter Mosaic of Mid Shelf Reef (St. Thomas), US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the Mid Shelf Reef south of St. Thomas, US Virgin IslandsNOAA's NOS/NCCOS/CCMA Biogeography Team,...

  9. NOAA TIFF Image - 1 m Backscatter Mosaic of Bajo de Cico, Puerto Rico, Project NF-07-06, 2007, UTM 19 NAD83 (NCEI Accession 0131853)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of Bajo de Cico off the coast of western Puerto Rico, collected using a Kongsberg EM 1002 (95 kHz)...

  10. NOAA TIFF Image - 2 m Backscatter Mosaic of Isla de Mona, PR, Project NF-07-06, 2007, UTM 19 NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 2 meter resolution backscatter mosaic of the southern coast of Isla de Mona, collected using a Kongsberg EM 1002 (95 kHz) multibeam...

  11. Work hardening mechanism in high nitrogen austenitic steel studied by in situ neutron diffraction and in situ electron backscattering diffraction

    International Nuclear Information System (INIS)

    With a focus on microstructural hierarchy, work hardening behaviour in high nitrogen-bearing austenitic steel (HNS) was investigated mainly by a combined technique of in situ neutron diffraction and in situ electron backscattering diffraction (EBSD). Stress partitioning due to difference in deformability among grains is enhanced in HNS. The larger stress partitioning among [h k l]-oriented family grains seems to realize high work hardening at a small strain. At a larger strain, dislocation density is higher in HNS than in low nitrogen austenitic steel (LNS), which is a possible reason for high work hardening after straining proceeds, resulting in large uniform elongation.

  12. An assessment of COMSCAN, a Compton backscatter imaging camera, for the one-sided non-destructive inspection of aerospace components

    Science.gov (United States)

    Sponder, L.

    1993-07-01

    This report presents some results obtained using a Compton backscatter imaging camera, developed by Philips Industries, which were obtained during a visit to the Defense Research Establishment Pacific (DREP) during May/June 1992. Compton backscatter imaging is an X-ray technique which can be used to non-destructively inspect the interior of both metallic and non-metallic structures and, unlike conventional X-ray methods, requires access to only one side of the part being inspected.

  13. Detection of Subsurface Defects Using X-Ray Lateral Migration Radiography - A New Backscatter Imaging Technique

    Energy Technology Data Exchange (ETDEWEB)

    Edward T. Dugan; Alan M. Jacobs

    2003-02-10

    A new Compton X-ray backscatter imaging technique called lateral migration radiography (LMR) is applied to detecting a class of sub-surface defects in materials and structures of industrial importance. These include flaws and defects for which there is either no known method or an effective method for detection. Examples are delamination in layered composite structures, defects in deposited coatings on metal surfaces such as in aircraft jet engine components and geometrical structural/composition changes (e.g. due to corrosion) on the inside of shell-like components with only outside surface area access.Research efforts include: the construction of simulated flawed test objects on which experimental measurements are performed to establish LMR flaw detection capabilities; performance of Monte Carlo simulations of these measurements to assist in predicting optimum source-detector configurations and to help obtain a detailed understanding of the physics of lateral migration in small voids and how this impacts the resulting LMR image contrasts; the procurement of samples of materials of industrial importance with flaws and defects; the application of LMR to the detection of flaws and defects in these samples; the development of a multi-detector scanning system to provide for faster, more effective flaw detection; and a determination, for the types of samples examined, of the limits and capabilities of flaw detection using LMR.LMR imaging measurements on the machined samples showed that the optimum contrast in flaw-to-background signal intensity occurred at an X-ray energy of 75 kVp for the aluminum samples and at 35 kVp for the Delrin sample. Monte Carlo simulations and experimental measurements on the aluminum samples showed that LMR is capable of detecting defects down to the tens of microns range. Measurements on the aluminum samples also showed that LMR is capable of detecting relatively small composition variations; a 30 % difference in image intensity was

  14. The role of dislocations in varied olivine deformation mechanisms investigated using high-angular resolution electron backscatter diffraction

    Science.gov (United States)

    Wallis, David; Hansen, Lars; Britton, Ben; Wilkinson, Angus

    2016-04-01

    Experimentally-derived flow laws can be used to predict the rheology of rocks deformed under natural conditions only if the same microphysical processes can be demonstrated to control the rate-limiting deformation mechanism in both cases. Olivine rheology may exert a principle control on the strength of the lithosphere, and therefore considerable research effort has been applied to assessing its rheology through experimental, geological, and geophysical approaches. Nonetheless, considerable uncertainty remains regarding the dominant deformation mechanisms in the upper mantle. This uncertainty arises in large part due to our limited understanding of the fundamental deformation processes associated with each mechanism. Future improvements to microphysical models of distinct deformation mechanisms require new insight into the contributions those fundamental processes to the macroscopic behaviour. The dynamics of dislocations is central to modelling viscous deformation of olivine, but characterisation techniques capable of constraining dislocation types, densities, and distributions over the critical grain to polycrystal length-scales have been lacking. High angular resolution electron backscatter diffraction (HR-EBSD), developed and increasingly applied in the material sciences, offers an approach capable of such analyses. HR-EBSD utilises diffraction pattern image cross-correlation to achieve dramatically improved angular resolution (~0.01°) of lattice orientation gradients compared to conventional Hough-based EBSD (~0.5°). This angular resolution allows very low densities (≥ 10^11 m^-2) of geometrically necessary dislocations (GND) to be resolved, facilitating analysis of a wide range of dislocation microstructures. We have developed the application of HR-EBSD to olivine and applied it to samples deformed both experimentally and naturally in grain-size sensitive and grain-size insensitive regimes. The results quantitatively highlight variations in the types and

  15. Texture analysis of melt-spun Ni-Mn-Ga tapes by means of electron backscatter diffraction (EBSD)

    Science.gov (United States)

    Koblischka-Veneva, A.; Koblischka, M. R.; Schmauch, J.; Mitra, A.; Panda, A. K.

    2010-01-01

    A texture analysis is performed by means of the electron-backscatter diffraction technique (EBSD) on melt-spun ribbon-like samples of the composition Ni52.5Mn24.5Ga23 (at.-%) were prepared. A dedicated surface treatment is required in order to achieve high quality Kikuchi patterns. For this purpose, mechanical polishing plus ion polishing was employed. EBSD analysis and transmission electron microscopy revealed that the samples have a polycrystalline, granular morphology, with grain sizes around 1 - 2 μm. Several larger grains being present in the region selected for EBSD analysis, and many small grains are found, even embedded in the larger ones. The larger grains exhibit a common direction of elongation, yielding to a specific texture.

  16. Two and three dimensional electron backscattered diffraction analysis of solid oxide cells materials

    DEFF Research Database (Denmark)

    Saowadee, Nath

    There are two main technique were developed in this work: a technique to calculate grain boundary energy and pressure and a technique to measure lattice constant from EBSD. The techniques were applied to Nb-doped Strontium titanate (STN) and yttria stabilized zirconia (YSZ) which are commonly used...... in solid oxide fuel cell and electrolysis cell. Conductivity of STN is one of the important properties that researchers desire to improve. Grin boundary conductivity contributes to the overall conductivity of the STN. Grain boundary density controlled by mainly grain growth in material processing. Grain...... compared to a mechanically polished surface but yielded a high pattern quality on YSZ. The difference between STN and YSZ pattern quality is thought to be caused by difference in the degree of ion damage as their backscatter coefficients and ion penetration depths are virtually identical. Reducing the FIB...

  17. Heavy Element Staining of Sedimentary Organic Matter Functional Groups for Backscattered Electron Imaging Marquage par éléments lourds de la matière organique sédimentaire pour la microscopie électronique en électrons rétrodiffusés

    Directory of Open Access Journals (Sweden)

    Belin-Geindre S.

    2006-11-01

    Full Text Available The scanning electron microscopy (SEM in backscattered electron mode (BSE, which imaging is based upon atomic number (Z contrasts between constituents, allows to visualize the organic matter distribution within the sediment. However the precise identification of organic matter is not possible as all the organic matter appears black. The contrasts between the different types of organic matter were enhanced for the use of the SEM/BSE imaging by staining organic matter with high Z elements. Experimental procedure was tested in terms of faisability, selectivity and specificity on polymers containing functional groups likely to occur in sedimentary organic matter. Then staining was applied to sedimentary organic matter, i. e. to purely organic sediments (algal mats, kukersite and coal and to clayey sediments (Kimmeridge Clay Formation. The chosen staining solutions comprised : ruthenium tetroxide, osmium tetroxide, phosphotungstic acid (PTA and silver methenamine. Samples were immersed in staining solutions for 24 hours, rinsed and observed with SEM/BSE. The penetration depth ranges between 20 and 150 µm. Other complementary tests with ruthenium tetroxide and mercury acetate were also performed on polymers. Tests with PTA, silver methenamine and osmium tetroxide were satisfying and presented a more or less broad specificity. Osmium allows the distinction of each algal laminite of the algal mat. The different parts of the kukersite react specifically with osmium, PTA and silver. The coal constituents display a specific staining with silver methenamine. Osmium and PTA allow in the Kimmeridge Clay sample (a to differenciate several types of organic particles according to their chemical composition; (b to locate the organic matter finely dispersed within the mineral, clayey matrix. La microscopie électronique à balayage (MEB en mode électrons rétrodiffusés (ER permet de visualiser la répartition de toute la matière organique d'un sédiment (Belin

  18. Effects of focused ion beam milling on electron backscatter diffraction patterns in strontium titanate and stabilized zirconia

    DEFF Research Database (Denmark)

    Saowadee, Nath; Agersted, Karsten; Bowen, Jacob R.

    2012-01-01

    This study investigates the effect of focused ion beam (FIB) current and accelerating voltage on electron backscatter diffraction pattern quality of yttria‐stabilized zirconia (YSZ) and Nb‐doped strontium titanate (STN) to optimize data quality and acquisition time for 3D‐EBSD experiments by FIB...... serial sectioning. Band contrast and band slope were used to describe the pattern quality. The FIB probe currents investigated ranged from 100 to 5000 pA and the accelerating voltage was either 30 or 5 kV. The results show that 30 kV FIB milling induced a significant reduction of the pattern quality...... milling. For 3D‐EBSD experiments of a material such as STN, it is recommended to combine a high kV FIB milling and low kV polishing for each slice in order to optimize the data quality and acquisition time....

  19. On the mechanistic basis of fatigue crack nucleation in Ni superalloy containing inclusions using high resolution electron backscatter diffraction

    International Nuclear Information System (INIS)

    A series of interrupted three-point bend low-cycle fatigue tests were carried out on a powder metallurgy FHG96 nickel superalloy sample containing non-metallic inclusions. High resolution electron backscatter diffraction (HR-EBSD) was used to characterise the distribution and evolution of geometrically necessary dislocation (GND) density, residual stress and total dislocation density near a non-metallic inclusion. A systematic study of room temperature cyclic deformation is presented in which slip localisation, cyclic hardening, ratcheting and stabilisation occur, through to crack formation and microstructurally-sensitive propagation. Particular focus is brought to bear at the inclusion–matrix interface. Complex inhomogeneous deformation structures were directly observed from the first few loading cycles, and these structures were found not to vary significantly with increasing number of cycles. A clear link was observed between crack nucleation site and microstructurally-sensitive growth path and the spatially-resolved sites of extreme values of residual stress and GND density

  20. Deformation micro-mechanism for compression of magnesium alloys at room temperature analyzed by electron backscatter diffraction

    International Nuclear Information System (INIS)

    Highlights: • In-situ tracking on the evolution of grains orientation of magnesium alloy was carried out by EBSD. • Distributions of twin bands were closely related to the activation of extension twin variants. • Activation of extension twin significantly changes the order of Schmid factor of slips. • Pyramidal slips become the dominant deformation mode at the late stage of compression. - Abstract: In-situ tracking on the evolution of grains orientation of rolled magnesium alloy sheets compressed uniaxially at room temperature was carried out by the method of electron backscatter diffraction (EBSD), and meanwhile, distributions of twin bands, activations of twin and slips were also analyzed. The results show that the distributions of twin bands were closely related to the activation of extension twin variants. The activation of extension twin significantly changes the order of Schmid factor of different slips, and accordingly affects the activation of slips during the subsequent deformation

  1. Novel CMOS electron imaging sensor

    Science.gov (United States)

    Finkelstein, Hod; Ginosar, Ran

    1998-09-01

    Electron detector arrays are employed in numerous imaging applications, from low-light-light-level imaging to astronomy, electron microscopy, and nuclear instrumentation. The majority of these detectors are fabricated with dedicated processes, use the semiconductor as a stopping and detecting layer, and utilize CCD-type charge transfer and detection. We present a new detector, wherein electrons are stopped by an exposed metal layer, and are subsequently detected either through charge collection in a CCD-type well, or by a measurement of a potential drop across a capacitor which is discharged by these electrons. Spatial localization is achieved by use of two metal planes, one for protecting the underlying gate structures, and another, with metal pixel structures, for 2D detection. The new device does not suffer from semiconductor non-uniformities, and blooming effects are minimized. It is effective for electrons with energies of 2-6 keV. The unique structure makes it possible to achieve a high fill factor, and to incorporate on-chip processing. An imaging chip implementing several test structures incorporating the new detector has been fabricated using a 2 micron double-poly double-metal process, and tested inside a JEOL 640 electron microscope.

  2. A correlative approach to segmenting phases and ferrite morphologies in transformation-induced plasticity steel using electron back-scattering diffraction and energy dispersive X-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gazder, Azdiar A., E-mail: azdiar@uow.edu.au [Electron Microscopy Centre, University of Wollongong, New South Wales 2500 (Australia); Al-Harbi, Fayez; Spanke, Hendrik Th. [School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, New South Wales 2522 (Australia); Mitchell, David R.G. [Electron Microscopy Centre, University of Wollongong, New South Wales 2500 (Australia); Pereloma, Elena V. [Electron Microscopy Centre, University of Wollongong, New South Wales 2500 (Australia); School of Mechanical, Materials and Mechatronic Engineering, University of Wollongong, New South Wales 2522 (Australia)

    2014-12-15

    Using a combination of electron back-scattering diffraction and energy dispersive X-ray spectroscopy data, a segmentation procedure was developed to comprehensively distinguish austenite, martensite, polygonal ferrite, ferrite in granular bainite and bainitic ferrite laths in a thermo-mechanically processed low-Si, high-Al transformation-induced plasticity steel. The efficacy of the ferrite morphologies segmentation procedure was verified by transmission electron microscopy. The variation in carbon content between the ferrite in granular bainite and bainitic ferrite laths was explained on the basis of carbon partitioning during their growth. - Highlights: • Multi-condition segmentation of austenite, martensite, polygonal ferrite and ferrite in bainite. • Ferrites in granular bainite and bainitic ferrite segmented by variation in relative carbon counts. • Carbon partitioning during growth explains variation in carbon content of ferrites in bainites. • Developed EBSD image processing tools can be applied to the microstructures of a variety of alloys. • EBSD-based segmentation procedure verified by correlative TEM results.

  3. A correlative approach to segmenting phases and ferrite morphologies in transformation-induced plasticity steel using electron back-scattering diffraction and energy dispersive X-ray spectroscopy

    International Nuclear Information System (INIS)

    Using a combination of electron back-scattering diffraction and energy dispersive X-ray spectroscopy data, a segmentation procedure was developed to comprehensively distinguish austenite, martensite, polygonal ferrite, ferrite in granular bainite and bainitic ferrite laths in a thermo-mechanically processed low-Si, high-Al transformation-induced plasticity steel. The efficacy of the ferrite morphologies segmentation procedure was verified by transmission electron microscopy. The variation in carbon content between the ferrite in granular bainite and bainitic ferrite laths was explained on the basis of carbon partitioning during their growth. - Highlights: • Multi-condition segmentation of austenite, martensite, polygonal ferrite and ferrite in bainite. • Ferrites in granular bainite and bainitic ferrite segmented by variation in relative carbon counts. • Carbon partitioning during growth explains variation in carbon content of ferrites in bainites. • Developed EBSD image processing tools can be applied to the microstructures of a variety of alloys. • EBSD-based segmentation procedure verified by correlative TEM results

  4. Effects of focused ion beam milling on electron backscatter diffraction patterns in strontium titanate and stabilized zirconia.

    Science.gov (United States)

    Saowadee, N; Agersted, K; Bowen, J R

    2012-06-01

    This study investigates the effect of focused ion beam (FIB) current and accelerating voltage on electron backscatter diffraction pattern quality of yttria-stabilized zirconia (YSZ) and Nb-doped strontium titanate (STN) to optimize data quality and acquisition time for 3D-EBSD experiments by FIB serial sectioning. Band contrast and band slope were used to describe the pattern quality. The FIB probe currents investigated ranged from 100 to 5000 pA and the accelerating voltage was either 30 or 5 kV. The results show that 30 kV FIB milling induced a significant reduction of the pattern quality of STN samples compared to a mechanically polished surface but yielded a high pattern quality on YSZ. The difference between STN and YSZ pattern quality is thought to be caused by difference in the degree of ion damage as their backscatter coefficients and ion penetration depths are virtually identical. Reducing the FIB probe current from 5000 to 100 pA improved the pattern quality by 20% for STN but only showed a marginal improvement for YSZ. On STN, a conductive coating can help to improve the pattern quality and 5 kV polishing can lead to a 100% improvement of the pattern quality relatively to 30 kV FIB milling. For 3D-EBSD experiments of a material such as STN, it is recommended to combine a high kV FIB milling and low kV polishing for each slice in order to optimize the data quality and acquisition time. PMID:22582798

  5. Electron Backscatter Diffraction (EBSD) Analysis and U-Pb Geochronology of the Oldest Lunar Zircon: Constraining Early Lunar Differentiation and Dating Impact-Related Deformation

    Science.gov (United States)

    Timms, Nick; Nemchin, Alexander; Grange, Marion; Reddy, Steve; Pidgeon, Bob; Geisler, Thorsten; Meyer, Chuck

    2009-01-01

    The evolution of the early moon was dominated by two processes (i) crystallization of the Lunar Magma Ocean (LMO) and differentiation of potassium-rare earth element-phosphorous-rich residual magma reservoir referred to as KREEP, and (ii) an intense meteorite bombardment referred to as lunar cataclysm . The exact timing of these processes is disputed, and resolution relies on collection and interpretation of precise age data. This study examines the microstructure and geochronology of zircon from lunar impact breccias collected during the Apollo 17 mission. A large zircon clast within lunar breccia 72215,195 shows sector zoning in optical microscopy, cathodoluminescence (CL) imaging and Raman mapping, and indicates that it was a relict fragment of a much larger magmatic grain. Sensitive high resolution ion microprobe (SHRIMP) U-Pb analysis of the zircon shows that U and Th concentration correlate with sector zoning, with darkest CL domains corresponding with high-U and Th (approx.150 and approx.100 ppm respectively), and the brightest-CL sectors containing approx.30-50 ppm U and approx.10-20 ppm Th. This indicates that variations in optical CL and Raman properties correspond to differential accumulation of alpha-radiation damage in each sector. Electron backscatter diffraction (EBSD) mapping shows that the quality of electron backscatter patterns (band contrast) varies with sector zoning, with the poorest quality patterns obtained from high-U and Th, dark-CL zones. EBSD mapping also reveals a deformation microstructure that is cryptic in optical, CL and Raman imaging. Two orthogonal sets of straight discrete and gradational low-angle boundaries accommodate approx.12 misorientation across the grain. The deformation bands are parallel to the crystallographic {a}-planes of the zircon, have misorientation axes parallel to the c-axis, and are geometrically consistent with formation by dislocation creep associated with {010} slip. The deformation bands are unlike curved

  6. Grain size distributions of chalk from image analysis of electron micrographs

    DEFF Research Database (Denmark)

    Røgen, Birte; Gommesen, Lars; Fabricius, Ida Lykke

    2001-01-01

    In the chalk of the Ekofisk formation in the Chalk Group of the North Sea, substantial depth-related variations in porosityare observed. With the aim of obtaining a textural interpretation of these porositydata, we have developed a method to assess the grain size distribution of the chalk from...... image analysis. The chalk is composed of a fine-grained matrix of nannofossils and predominantlycalcitic fossil debris with larger microfossil grains, but the chalk may also contain significant amounts of silica and siliciclastic clay. For image analysis, we used backscatter electron images of epoxy......-impregnated, polished samples from the Ekofisk Formation, Tyra field, Danish North Sea. On backscatter images the calcite phase will appear light as opposed to the dark pore space. The procedure involves the combination of data acquired at two magnifications and bythis method analysis of only four images per sample...

  7. Artificial electron heating of winter mesospheric radar clouds (PMWE) and the interpretation of the radar backscatter variation during the heater cycling.

    Science.gov (United States)

    Kassa Bekele, Meseret; Havnes, Ove; La Hoz, Cesar; Baroni, Giovanni; Rietveld, Mike; Biebricher, Alexander

    The effect of artificial electron heating (in our case with the EISCAT Heating Facility) on the Polar Mesospheric Winter Echoes (PMWE) the weak radar clouds which occur in the winter mesosphere between heights 55 to 80 km, is normally different from its effect on the much stronger Polar Mesospheric Summer Echoes (PMSE) which occur between 80 and 90 km height. They both show a weakening of the backscatter when the heater is switched on, sometimes close to extinguishing of the radar backscatter, signaling that the increased electron pressure has smoothed the electron density gradients which are responsible for the coherent backscatter. However, while the PMSE backscatter very often show a considerable recovery during the 20 sec the heater (normally) is on and dust particles are charged more negatively by the heated electrons, this recovery is at best very weak for PMWE. The PMWE also have weak overshoots, where the backscatter flares up only by a factor 1.1 to 1.2 when the heater is switched off, compared to the undisturbed PMWE backscatter before the heater was switched on. For PMSE the overshoot factor can be as high as 7. This demonstrate that if dust particles control the PMWE their sizes must be much smaller than the PMSE particles. Modeling has shown that the likely PMWE dust sizes are in the range 3-4 nanometer making it probable that PMWE is associated with the small meteoric smoke particles. When the heater is switched off the charge of the dust particles and the intensity of the backscatter relax back to its undisturbed values. If the decharging mechanism was the same for the larger PMSE and the small PMWE dust particles one would expect a very much longer relaxation time for the PMWE than for the PMSE. The fact that the PMWE relaxation time is comparable to the PMSE show that the small meteoric dust particles must be de-charged by a more effective mechanism than ion attachment. We find that the photodetachment effect where photons of energy less than the

  8. An optical storage cavity-based, Compton-backscatter x-ray source using the MKV free electron laser

    Science.gov (United States)

    Hadmack, Michael R.

    A compact, high-brightness x-ray source is presently under development at the University of Hawai`i Free Electron Laser Laboratory. This source utilizes Compton backscattering of an infrared laser from a relativistic electron beam to produce a narrow beam of monochromatic x-rays. The scattering efficiency is greatly increased by tightly focusing the two beams at an interaction point within a near-concentric optical storage cavity, designed with high finesse to coherently stack the incident laser pulses and greatly enhance the number of photons available for scattering with the electron beam. This dissertation describes the effort and progress to integrate and characterize the most important and challenging aspects of the design of this system. A low-power, near-concentric, visible-light storage cavity has been constructed as a tool for the exploration of the performance, alignment procedures, and diagnostics required for the operation of a high power infrared storage cavity. The use of off-axis reflective focussing elements is essential to the design of the optical storage cavity, but requires exquisite alignment to minimize astigmatism and other optical aberrations. Experiments using a stabilized HeNe laser have revealed important performance characteristics, and allowed the development of critical alignment and calibration procedures, which can be directly applied to the high power infrared storage cavity. Integration of the optical and electron beams is similarly challenging. A scanning-wire beam profiler has been constructed and tested, which allows for high resolution measurement of the size and position of the laser and electron beams at the interaction point. This apparatus has demonstrated that the electron and laser beams can be co-aligned with a precision of less than 10 microm, as required to maximize the x-ray production rate. Equally important is the stabilization of the phase of the GHz repetition rate electron pulses arriving at the interaction point

  9. Conditions required for high quality high magnification images in secondary electron-I scanning electron microscopy.

    Science.gov (United States)

    Peters, K R

    1982-01-01

    High quality of secondary electron (SE) images, taken at useful magnifications of 100,000 to 200,000, require new signal generation and collection methods and new metal coating procedures. High quality is defined as the condition under which image contrast describes accurately the topographic features of the specimen in a size range that approximates the beam diameter. Such high resolution contrasts are produced by the SE (SE-I) generated by a small electron probe on the specimen surface. Tobacco mosiac virus and ferritin molecules deposited on bulk substrates were introduced as test specimens to check the image quality obtained. The SE-I signal contrast could be imaged when SE (SE-III), produced by backscattered electrons (BSE) at the pole piece of the final lens, were eliminated with an electron absorption device attached to the pole piece. This signal collection procedure will be referred to as "Secondary Electron-I Image" (SE-I image) mode. In addition to the SE-III, BSE generate SE-II in the specimen itself. On specimens deposited on bulk gold or platinum, and coated with the same metals SE-II produced a microroughness contrast that limited particle resolution in the SE-I image mode to approximately 10 nm. Reduction of SE-II and enrichment of the signal in SE-I was achieved by using continuous fine crystalline coatings of tantalum, niobium and chromium. By applying these metals in films of approximately 2.0 nm thickness, the SE-I contrast generation was found to be indepedent of the atomic number of the metal. Edge sharpness was improved when the specimens were coated with low atomic number metals. Under these conditions, the quality of images obtained in SE-I image mode equals that of images obtained in TEM from identically coated specimens and was limited only by the size of the topographic details, beam diameter and beam current. PMID:7184136

  10. Aspects of Electron Acoustic Wave Physics in Laser Backscatter from Plasmas

    CERN Document Server

    Sircombe, N J; Dendy, R O

    2006-01-01

    Recent experimental results from the Trident laser confirm the importance of kinetic effects in determining laser reflectivities at high intensities. Examples observed include scattering from low frequency electron acoustic waves (EAWs), and the first few stages of a cascade towards turbulence through the Langmuir decay instability. Interpretive and predictive computational capability in this area is assisted by the development of Vlasov codes, which offer high velocity space resolution in high energy regions of particle phase space, and do not require analytical pre-processing of the fundamental equations. A direct Vlasov solver, capable of resolving these kinetic processes, is used here to address fundamental aspects of the existence and stability of the electron acoustic wave, together with its collective scattering properties. These simulations are extended to realistic laser and plasma parameters characteristic of single hot-spot experiments. Results are in qualitative agreement with experiments displayi...

  11. Solution to the transport equation for electron backscattering on massive materials

    International Nuclear Information System (INIS)

    The scattering of a monoenergetic electron beam (Albedo problem) vertical to the plane of the boundary layer of a massive material is treated as transportproblem using the Boltzmann Transport Equation (BTE). The strong anistropic to 1 standardized differential effective cross section (DEC) of the single scattering of the electrons enters into the integral term. A complete, orthogonal set of solution units of the BTE can be given by a new type of approximation of the DEC in a generalization of a solution method from CASE 1960. By continuously changing an anisotropy parameter, the region of strong anisotropic and isotropic single scattering is simultaneously determined, the case results are taken as special case. (orig./RW)

  12. Backscatter imagery in Jobos Bay

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1x1 meter resolution backscatter mosaic of Jobos Bay, Puerto Rico (in NAD83 UTM 19 North). The backscatter values are in relative 8-bit (0 –...

  13. Pseudo sidescan images from backscatter amplitude data of the Hydrosweep multibean sonar system

    Digital Repository Service at National Institute of Oceanography (India)

    Kodagali, V.N.; Hagen, R.; Schenke, H.W.

    in the southeast Pacific Ocean is presented. The two sidescan images are perfectly comparable. This result will enhance the utility of the Hydrosweep multibeam system so that, even in the absence of sidescan option, the offline pseudo sidescan images can...

  14. Study of grain boundary properties in Ag-clad Bi2Sr2Ca2Cu3Ox tapes by multi-phase electron backscatter diffraction analysis

    Science.gov (United States)

    Koblischka-Veneva, A.; Koblischka, M. R.

    2008-01-01

    The properties of grain boundaries within Ag-clad (Pb,Bi)2Sr2Ca2Cu3Ox (Bi-2223) tapes are studied by means of electron backscatter diffraction (EBSD). The achieved high image quality of the Kikuchi patterns enables multi-phase EBSD scans including Bi-2223, Bi2Sr2CaCu2Ox (Bi-2212), Bi2Sr2CuOx (Bi-2201), (Sr,Ca)14Cu24O41 and Ag to be performed. For the EBSD scans a maximum spatial resolution of 30 nm was reached enabling a detailed orientation analysis. The nature of the grain boundaries is discussed on the base of the EBSD data. While the main orientation of the tape is in [0 0 1] direction, a large number of misorientations is detected. These misorientations are visualized using crystal direction (CD) maps. Furthermore, EBSD enables the spatially resolved mapping of the misorientation angles within each phase separately. The influence of these grain boundaries on the current transport properties is discussed.

  15. Silicon location through backscattered electron imaging and X-ray microanalysis in leaves of Cyperus ligularis L. and Rhynchospora aberrans C. B. Clarke (Cyperaceae Localização de sílica por elétrons retroespalhados em folhas de Cyperus ligularis L. and Rhynchospora aberrans C. B. Clarke (Cyperaceae

    Directory of Open Access Journals (Sweden)

    Maria Emília Maranhão Estelita

    2012-06-01

    Full Text Available The Cyperaceae show the ability to incorporate silicon by depositing colloidal silica, which is recorded by the occurrence of projections in the form of cones, in inner tangential walls of some epidermal cells or "silica cells". Leaves of C. ligularis and R. aberrans were analyzed through the technique of electron backscatter. Cyperus ligularis accumulates silica, in addition to "silica cells", in some stomata, trichomes and the cell walls that surround the cavities of the aerenchyma. The silica in the latter occurs in various forms; however, the cells located near the vascular bundles have conical projections, similar to those of the epidermis. Rhynchospora aberrans presents "silica cells" whose projections have tapered "satellites". In this species, silica also occurs in stomata and certain epidermal cells adjacent to them. It appears that the silicon deposition occurs in combination with the wall (with no apparent structural changes, and structures of secretion, or projections of the wall. These structural changes in the species, and location, are probably related to functional and environmental factors, especially the soil, in addition to relation with taxonomic groups.As Cyperaceae têm a capacidade de incorporação do ácido silícico mediante depósito de sílica coloidal, que é registrada pela ocorrência de projeções sob a forma de cones, nas paredes tangenciais internas de determinadas células epidérmicas ou "células de sílica". Folhas de C. ligularis e R. aberrans foram analisadas pela técnica de elétrons retroespalhados. C. ligularis além de acumular sílica nas "células de sílica", acumula também em alguns estômatos, nos tricomas e nas paredes das células que contornam as cavidades do aerênquima. Este último apresenta formas diversas, entretanto, as células que se localizam junto aos feixes vasculares mostram projeções cônicas, semelhantes àquelas da epiderme. R. aberrans contém "células de silica" cujas

  16. Mapping local orientation of aligned fibrous scatterers for cancerous tissues using backscattering Mueller matrix imaging

    Science.gov (United States)

    He, Honghui; Sun, Minghao; Zeng, Nan; Du, E.; Liu, Shaoxiong; Guo, Yihong; Wu, Jian; He, Yonghong; Ma, Hui

    2014-10-01

    Polarization measurements are sensitive to the microstructure of tissues and can be used to detect pathological changes. Many tissues contain anisotropic fibrous structures. We obtain the local orientation of aligned fibrous scatterers using different groups of the backscattering Mueller matrix elements. Experiments on concentrically well-aligned silk fibers and unstained human papillary thyroid carcinoma tissues show that the m22, m33, m23, and m32 elements have better contrast but higher degeneracy for the extraction of orientation angles. The m12 and m13 elements show lower contrast, but allow us to determine the orientation angle for the fibrous scatterers along all directions. Moreover, Monte Carlo simulations based on the sphere-cylinder scattering model indicate that the oblique incidence of the illumination beam introduces some errors in the orientation angles obtained by both methods. Mapping the local orientation of anisotropic tissues may not only provide information on pathological changes, but can also give new leads to reduce the orientation dependence of polarization measurements.

  17. Texture development study during the primary recrystallization of ferritic steels by using X ray and electron backscattering diffraction

    International Nuclear Information System (INIS)

    X ray and electron backscattering diffraction, in distinct levels, were applied to evaluate microstructural changes in two low carbon ferritic steels (2 per cent Si and ABNT 1006), observing the texture development in cold lamination step (skin-pass) and in the subsequent annealing at 760 deg C. In these two steels, results showed that after the skin-pass and annealing in the conditions of the present work, the observed phenomenon is the primary recrystallization. By applying skin-pass dislocations were introduced mostly in low Taylor factor grains as they are prone to be more deformed. Nucleation and grain growth were observed in high density dislocation cell regions. Silicon presence delayed the recovery favoring the sub-boundaries increase. It was not observed the abnormal grain growth, even in the presence of Gross grains. CSL boundaries did not guarantee the grains growth. Growing nuclei gave rise to grains with distinct orientations, showing that the grain growth was not dependent on the previous presence of grains with the developed orientation. This fact demonstrates that the abnormal grain growth is not necessarily related to the Gross grains. (author)

  18. Standard practice for determining average grain size using electron backscatter diffraction (EBSD) in fully recrystallized polycrystalline materials

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice is used to determine grain size from measurements of grain areas from automated electron backscatter diffraction (EBSD) scans of polycrystalline materials. 1.2 The intent of this practice is to standardize operation of an automated EBSD instrument to measure ASTM G directly from crystal orientation. The guidelines and caveats of E112 apply here, but the focus of this standard is on EBSD practice. 1.3 This practice is only applicable to fully recrystallized materials. 1.4 This practice is applicable to any crystalline material which produces EBSD patterns of sufficient quality that a high percentage of the patterns can be reliably indexed using automated indexing software. 1.5 The practice is applicable to any type of grain structure or grain size distribution. 1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.7 The values stated in inch-pound units are to be regarded as standard. The values given in parenthe...

  19. Characterization of Sputtered CdTe Thin Films with Electron Backscatter Diffraction and Correlation with Device Performance.

    Science.gov (United States)

    Nowell, Matthew M; Scarpulla, Michael A; Paudel, Naba R; Wieland, Kristopher A; Compaan, Alvin D; Liu, Xiangxin

    2015-08-01

    The performance of polycrystalline CdTe photovoltaic thin films is expected to depend on the grain boundary density and corresponding grain size of the film microstructure. However, the electrical performance of grain boundaries within these films is not well understood, and can be beneficial, harmful, or neutral in terms of film performance. Electron backscatter diffraction has been used to characterize the grain size, grain boundary structure, and crystallographic texture of sputtered CdTe at varying deposition pressures before and after CdCl2 treatment in order to correlate performance with microstructure. Weak fiber textures were observed in the as-deposited films, with (111) textures present at lower deposition pressures and (110) textures observed at higher deposition pressures. The CdCl2-treated samples exhibited significant grain recrystallization with a high fraction of twin boundaries. Good correlation of solar cell efficiency was observed with twin-corrected grain size while poor correlation was found if the twin boundaries were considered as grain boundaries in the grain size determination. This implies that the twin boundaries are neutral with respect to recombination and carrier transport. PMID:26077102

  20. Assessment of surface hardening effects from shot peening on a Ni-based alloy using electron backscatter diffraction techniques

    International Nuclear Information System (INIS)

    An electron backscatter diffraction (EBSD)-based tool is described to assess the depth of strain-hardening effects of shot-peening treatments applied to the Ni-based superalloy, Udimet (copy right) alloy 720Li. The method consists of a statistical analysis of a number of data points from each grain scanned based on the grain orientation spread and their relative position from the shot-peened edge. The output is a quantitative measure of the depth of strain-hardening effects. The tool is used at various shot-peening intensities to demonstrate the ability to distinguish between these changes, using a range of intensities from 4 to 10 Almen. An increase in shot-peening intensity is observed to increase the depth of strain-hardening effects in the alloy. A comparison with residual stress measurements using X-ray diffraction for the same material shows that the strain-hardened depth determined by EBSD extends to approximately half the distance of the residual stress present due to shot peening. A comparison is also made with predicted profiles from the PeenstressSM model and subsequent microhardness testing. A positive correlation is observed between strained hardened depth and surface roughness of the peened samples. In each case, the increases in surface roughness and strain-hardened depth diminish toward the upper end of the shot-peening intensity range studied for this alloy.

  1. Advances in imaging and electron physics

    CERN Document Server

    Hawkes, Peter W

    1995-01-01

    Academic Press is pleased to announce the creation of Advances in Imaging and Electron Physics. This serial publication results from the merger of two long running serials--Advances in Electronics and Electron Physics and Advances in Optical & Electron Microscopy. Advances in Imaging & Electron Physics will feature extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies,microlithography, image science and digital image processing, electromagnetic wave propagation, electron microscopy, and the computing methods used in all these domains. Continuation order customers for either of the original Advances will receiveVolume 90, the first combined volume.

  2. Advances in imaging and electron physics

    CERN Document Server

    Mulvey, Tom

    1995-01-01

    Academic Press is pleased to announce the creation of Advances in Imaging and Electron Physics. This serial publication results from the merger of two long-running serials--Advances in Electronics and Electron Physics and Advances in Optical & Electron Microscopy. Advances in Imaging & Electron Physics will feature extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies,microlithography, image science and digital image processing, electromagnetic wave propagation, electron microscopy, and the computing methods used in all these domains.

  3. Electron backscatter diffraction analysis on the microstructures of electrolytic Cu deposition in the through hole filling process

    Energy Technology Data Exchange (ETDEWEB)

    Ho, C.E., E-mail: ceho1975@hotmail.com [Department of Chemical Engineering and Materials Science, Yuan Ze University, Taiwan, ROC (China); Liao, C.W. [Department of Chemical Engineering and Materials Science, Yuan Ze University, Taiwan, ROC (China); School of Physics and Technology, Wuhan University, Wuhan, Hubei 430072 (China); Pan, C.X. [School of Physics and Technology, Wuhan University, Wuhan, Hubei 430072 (China); Chen, H.J. [Department of Chemical Engineering and Materials Science, Yuan Ze University, Taiwan, ROC (China); Kuo, J.C.; Chen, D. [Department of Materials Science and Engineering, National Cheng Kung University, Taiwan, ROC (China)

    2013-10-01

    Through hole (TH) filling by electrolytic Cu deposition has become a critical process for high density interconnection technologies associated with three-dimensional packaging. In this study, the morphological and crystallographic evolutions of the electrolytic Cu TH filling with the plating time (t) were investigated using an optical microscope and a field-emission scanning electron microscope equipped with an electron backscatter diffraction (EBSD) analysis system. The Cu deposition rate in the TH was strongly dependent on t, which was established at a moderate rate of ∼ 0.3 μm/min at t = 40 min–74 min, then dramatically accelerated to ∼ 4 μm/min at t = 74 min–80 min (termed “fast deposition regime”), and subsequently decelerated in the final plating regime (t = 80 min–100 min). EBSD analyses showed that the electrolytic Cu predominantly possessed high-angle grain boundaries with strong coincidence site lattices at ∑3 (60° rotation at <111>) and ∑9 (38.9° rotation at <101>) for all t examined. Interestingly, the [111]‖TD (transverse direction) orientation displayed a relatively strong presence in the initial induction regime, while the [111]‖TD + [101]‖TD orientations with large grain sizes became dominant in the fast deposition regime (i.e., t = 74 min–80 min), and there was a very low concentration of the [111]‖TD orientation in the final deposition regime. This research offered a better understanding of the morphological and crystallographic evolutions in each stage of the electrolytic Cu TH filling. - Highlights: • Through hole (TH) filling by electrolytic Cu deposition • The Cu deposition rate is strongly dependent on the plating time in the THs. • The dominant Cu orientations were [111]‖TD (transverse direction) and [101]‖TD. • Cu possessed high angle grain boundaries with strong coincidence site lattices.

  4. Electron backscatter diffraction characterization of electrolytic Cu deposition in the blind-hole structure: Current density effect

    Energy Technology Data Exchange (ETDEWEB)

    Ho, C.E., E-mail: ceho1975@hotmail.com; Chen, C.C.; Hsu, L.H.; Lu, M.K.

    2015-06-01

    Blind-hole (BH) filling via direct-current Cu electrodeposition is widely used in high-density interconnection technology for advanced printed circuit boards (PCBs). In this study, electrolytic Cu BH fillings deposited at various current densities (j = 2, 4, 5, and 6 A/dm{sup 2}) were investigated using transmission X-ray microscopy (TXM), field-emission scanning electron microscopy (FE-SEM), and electron backscatter diffraction (EBSD). The TXM, FE-SEM, and EBSD investigations indicated that the Cu deposition morphology (e.g., void formation and concave surface Cu) and its crystallographic microstructure (e.g., orientation and twin structure) were strongly dependent on j. The formation of voids and concave surface Cu in the BH fillings inevitably degraded the thermomechanical and electrical characteristics of the Cu deposition, deteriorating the reliability of PCB Cu interconnection. These dependencies revealed that j is an important factor of the Cu electrodeposition in the BH structure and should be reduced to a level of j < 4 A/dm{sup 2} to avoid the undesired microstructures. This knowledge serves to advance the understanding of the role of the current density in the Cu BH filling process. - Highlights: • Pronounced effect of current density (j) on Cu blind-hole (BH) filling • High-current-density induced void formation in the BH structure. • Concave Cu surface was caused in a high-j electrodeposition process. • Crystallographic transition of the [111] Cu to [101] was induced by increasing j. • Formation of Cu twin structure (60° rotation at 〈111〉) strongly depended on j.

  5. Grain Growth Orientation and Anisotropy in Cu6Sn5 Intermetallic: Nanoindentation and Electron Backscatter Diffraction Analysis

    Science.gov (United States)

    Choudhury, Soud Farhan; Ladani, Leila

    2014-04-01

    As the size of joints in micro/nano-electronics diminishes, the role of intermetallic (IMC) layers becomes more significant. It was shown that solder joint strength is controlled largely by IMC strength at higher strain rates. Additionally, there is a possibility that very small joints are completely composed of IMCs. Further miniaturization of joints may result in statistical grain size effects. Therefore, it is essential to characterize IMC materials and understand their anisotropic mechanical properties. One of the most common types of IMCs in microelectronic joints is Cu6Sn5, which is formed in a variety of bonding materials with different compositions of Sn, Cu, and Ag. This work studies through nanoindentation elastic-plastic properties of a single grain of Cu6Sn5 IMC in a Sn-3.5Ag/Cu system with reflow soldering. Elastic properties such as elastic modulus and hardness were determined from the nanoindentation load-depth curve. The reverse analysis model described by Dao et al. was used to extract plastic properties such as yield strength and strain hardening exponent from nanoindentation data. Care was taken to achieve indentation of single grains with sufficient accuracy and repeatability. Electron backscatter diffraction (EBSD) mapping was used to determine orientation of Cu6Sn5 grains and to relate the orientation with the load-depth curve results of nanoindentation and the corresponding elastic and plastic properties. The EBSD results indicated that the Cu6Sn5 crystal structure is hexagonal. Columnar growth of the Cu6Sn5 grains was observed as the grains mostly grew along the c-axis of the crystal. Indentation of different grains parallel to the basal plane showed no significant difference in mechanical properties.

  6. Identification of magnetic Fe-Ti oxides in marine sediments by electron backscatter diffraction in scanning electron microscopy

    NARCIS (Netherlands)

    Franke, C.; Pennock, G.M.; Drury, M.R.; Engelmann, R.; Lattard, D.; Garming, J.F.L.; Dobeneck, T. von; Dekkers, M.J.

    2007-01-01

    In paleomagnetic and environmental magnetic studies the magnetomineralogical identification is usually based on a set of rock magnetic parameters, complemented by crystallographic and chemical information retrieved from X-ray diffraction (XRD), (electron) microscopy or energy dispersive spectroscopy

  7. Study of ferrous corrosion products on iron archaeological objects by electron backscattered diffraction (EBSD)

    Energy Technology Data Exchange (ETDEWEB)

    Azoulay, Ilanith; Conforto, Egle; Refait, Philippe; Remazeilles, Celine [FRE 3474 CNRS - Universite de La Rochelle, Laboratoire des Sciences de l' Ingenieur pour l' Environnement, La Rochelle cedex 01 (France)

    2013-02-15

    The corrosion of iron-based archaeomaterials in anoxic environments leads mainly to Fe(II) compounds, like the hydroxychloride {beta}-Fe{sub 2}(OH){sub 3}Cl, chukanovite Fe{sub 2}(OH){sub 2}CO{sub 3} or siderite FeCO{sub 3}. The understanding of the mechanisms then necessarily implies a thorough investigation of the chemical, mechanical and morphological characteristics of the Fe(II)-based layer that develops between the metal surface and the environment. In the peculiar case of Fe(II) compounds, generally very reactive towards O{sub 2}, the main concern is to prevent any transformation by air during the analysis. The EBSD technique is adapted on a scanning electron microscope (SEM) where the samples are analysed under vacuum and consequently sheltered from air. Different options offered by EBSD for phase characterisation and microstructural study were tested for the first time on the rust layers of two archaeological iron nails. Results were confronted to those obtained by micro-Raman spectroscopy, which was used as reference method. Magnetite, Fe(II) hydroxychloride {beta}-Fe{sub 2}(OH){sub 3}Cl and siderite were analysed successfully but improvements have to be brought for the study of other compounds such as iron oxyhydroxides and chukanovite. The choice of experimental parameters in our approach as well as the potentialities and limits of the technique for this kind of application are discussed. (orig.)

  8. Dependence of the relative backscatter cross section of 1-m density fluctuations in the auroral electrojet on the angle between electron drift and radar wave vector

    International Nuclear Information System (INIS)

    With the STARE radar system it is possible to measure, with high spatial and temporal resolution the electron drift velocity V/sub D/ and the relative amplitude of electron density fluctuations of 1-m wavelength in the auroral electrojet. These density fluctuations are generated by the combined effects of the two-stream and the gradient drift instabilities. We have determined the angular dependence of the backscatter intensity (which is proportional to the square of the amplitude of the density fluctuations) on the angle theta betweeen the electron drift direction and the direction from the scattering volume to the radar in the plane perpendicular to the magnetic field. We find a fluctuation minimum for theta = 900 and an increase towards theta = 00 over the whole velocity range up to 1000 m/s. This increase is small for velocities below the ion acoustic velocity C/sub N/ but reaches over 20 dB gain in the backscatter intensity (corresponding to a density fluctuation more than 10 times as great) for higher velocities. We explain that the backscatter is caused mainly by two-stream instability in the range cos theta>C/sub S//V/sub d/ and by secondary gradient drift instability elsewhere

  9. Determination of the analyzing power of the A4 Compton-backscattering polarimeter for the measurement of the longitudinal spin polarization of the MAMI electron beam

    International Nuclear Information System (INIS)

    The A4 experiment determines the strange quark contribution to the electromagnetic from factors of the nucleon by measuring the parity violation in elastic electron nucleon scattering. These measurements are carried out using the spin polarized electron beam of the Mainzer Mikrotron (MAMI) with beam energies in the range from 315 to 1508 MeV. For the data analysis it is essential to determine the degree of polarization of the electron beam in order to extract the physics asymmetry from the measured parity violating asymmetry. For this reason the A4 collaboration has developed a novel type of Compton laser backscattering polarimeter that allows for a non-destructive measurement of the beam polarization in parallel to the running parity experiment. In the scope of this work the polarimeter was refined in order to enable reliable continuous operation of the polarimeter. The data acquisition system for the photon and electron detector was re-designed and optimized to cope with high count rates. A novel detector (LYSO) for the backscattered photons was commissioned. Furthermore, GEANT4 simulations of the detectors have been performed and an analysis environment for the extraction of Compton asymmetries from the backscattered photon data has been developed. The analysis makes use of the possibility to detect backscattered photons in coincidence with the scattered electrons, thus tagging the photons. The tagging introduces a differential energy scale which enables the precise determination of the analyzing power. In this work the analyzing power of the polarimeter has been determined. Therefore, at a beam current of 20 μA the product of electron and laser polarization can be determined, while the parity experiment is running, with a statistical accuracy of 1 % in 24 hours at 855 MeV or 2=0.6 (GeV/c)2 the analysis yields a raw asymmetry of ARohPV=(-20.0±0.9stat) x 10-6 at the moment. For a beam polarization of 80 % the total error would be 1,68 x 10-6 with ΔPe/Pe=5

  10. Backscatter measurements for NIF ignition targets (invited).

    Science.gov (United States)

    Moody, J D; Datte, P; Krauter, K; Bond, E; Michel, P A; Glenzer, S H; Divol, L; Niemann, C; Suter, L; Meezan, N; MacGowan, B J; Hibbard, R; London, R; Kilkenny, J; Wallace, R; Kline, J L; Knittel, K; Frieders, G; Golick, B; Ross, G; Widmann, K; Jackson, J; Vernon, S; Clancy, T

    2010-10-01

    Backscattered light via laser-plasma instabilities has been measured in early NIF hohlraum experiments on two beam quads using a suite of detectors. A full aperture backscatter system and near backscatter imager (NBI) instrument separately measure the stimulated Brillouin and stimulated Raman scattered light. Both instruments work in conjunction to determine the total backscattered power to an accuracy of ∼15%. In order to achieve the power accuracy we have added time-resolution to the NBI for the first time. This capability provides a temporally resolved spatial image of the backscatter which can be viewed as a movie.

  11. A novel approach for site-specific atom probe specimen preparation by focused ion beam and transmission electron backscatter diffraction

    International Nuclear Information System (INIS)

    Atom probe tomography (APT) is a suitable technique for chemical analyses with almost atomic resolution. However, the time-consuming site-specific specimen preparation can be improved. Recently, transmission electron backscatter diffraction (t-EBSD) has been established for high resolution crystallographic analyses of thin foils. In this paper we present the first successful application of a combined focused ion beam (FIB)/t-EBSD preparation of site-specific APT specimens using the example of grain boundary segregation in technically pure molybdenum. It will be shown that the preparation of a grain boundary can be substantially accelerated by t-EBSD analyses in-between the annular milling FIB procedure in the same microscope. With this combined method, a grain boundary can easily be recognized and positioned in the first 220 nm of an APT sample much faster than e.g. with complementary investigations in a transmission electron microscope. Even more, the high resolution technique of t-EBSD gives the opportunity to get crystallographic information of the mapped area and, therefore, an analysis of the grain boundary character to support the interpretation of the APT data files. To optimize this newly developed technique for the application on needle-shaped APT specimens, a parameter study on enhanced background correction, acceleration voltage, and tilt angle was carried out. An acceleration voltage of 30 kV at specimen surface tilt angles between −45° and −35° from horizontal plane leads to the best results. Even for molybdenum the observation of crystal orientation data up to about 200 nm specimen thickness is possible. - Highlights: • We developed a new site-specific APT specimen preparation method by FIB and t-EBSD. • A grain boundary was positioned in the first 220 nm of the APT tip by the FIB/t-EBSD method. • Crystallographic information of the mapped area can be quickly obtained. • An acceleration voltage of 30 kV at specimen surface tilt angles

  12. X-ray Compton backscattering techniques for process tomography: imaging and characterization of materials

    Science.gov (United States)

    Zhu, P.; Duvauchelle, P.; Peix, G.; Babot, D.

    1996-03-01

    Non-destructive evaluation by Compton scattering using an industrial x-ray tube allows three-dimensional (3D) imaging of materials. The x-ray tube and the detector are set on the same side of the object. Thus, non-destructive evaluation of the wall of a tank, even when it is full, is possible without the requirement for the x-ray beam to cross the whole object. Several applications were tried in our laboratory. Besides 3D imaging, a method allowing thickness measurement of a wall was developed, which was especially suitable for multilayer compounds. The accuracy is 0957-0233/7/3/008/img1 mm. Compton scattering techniques also allow point-by-point density measurements in the near-surface zone of any component (even dense and bulky ones). An accuracy of 1% was achieved for light composite materials and also for dense components (0957-0233/7/3/008/img2) provided by powder metallurgy. A new application allows us to perform 3D imaging using a linear accelerator (6 MeV) as the photon source. Thus, testing can be performed inside a tank, even through a thick and dense wall (8 mm of steel).

  13. A correlative approach to segmenting phases and ferrite morphologies in transformation-induced plasticity steel using electron back-scattering diffraction and energy dispersive X-ray spectroscopy.

    Science.gov (United States)

    Gazder, Azdiar A; Al-Harbi, Fayez; Spanke, Hendrik Th; Mitchell, David R G; Pereloma, Elena V

    2014-12-01

    Using a combination of electron back-scattering diffraction and energy dispersive X-ray spectroscopy data, a segmentation procedure was developed to comprehensively distinguish austenite, martensite, polygonal ferrite, ferrite in granular bainite and bainitic ferrite laths in a thermo-mechanically processed low-Si, high-Al transformation-induced plasticity steel. The efficacy of the ferrite morphologies segmentation procedure was verified by transmission electron microscopy. The variation in carbon content between the ferrite in granular bainite and bainitic ferrite laths was explained on the basis of carbon partitioning during their growth.

  14. A correlative approach to segmenting phases and ferrite morphologies in transformation-induced plasticity steel using electron back-scattering diffraction and energy dispersive X-ray spectroscopy.

    Science.gov (United States)

    Gazder, Azdiar A; Al-Harbi, Fayez; Spanke, Hendrik Th; Mitchell, David R G; Pereloma, Elena V

    2014-12-01

    Using a combination of electron back-scattering diffraction and energy dispersive X-ray spectroscopy data, a segmentation procedure was developed to comprehensively distinguish austenite, martensite, polygonal ferrite, ferrite in granular bainite and bainitic ferrite laths in a thermo-mechanically processed low-Si, high-Al transformation-induced plasticity steel. The efficacy of the ferrite morphologies segmentation procedure was verified by transmission electron microscopy. The variation in carbon content between the ferrite in granular bainite and bainitic ferrite laths was explained on the basis of carbon partitioning during their growth. PMID:25126753

  15. NOAA TIFF Image - 4m Multibeam Backscatter for Red Snapper Research Areas in the South Atlantic Bight, 2010

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains unified Multibeam Backscatter GeoTiffs with 4x4 meter cell resolution describing the geomorphology of 15 areas along the shelf edge off the...

  16. NOAA TIFF Image - 3m Backscatter Mosaic, Florida Deep Coral Areas - Lost Coast Explorer - (2010), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 3x3 meter cell size representing the backscatter (intensity) of several deep coral priority areas off the Atlantic...

  17. NOAA TIFF Image - 50m Backscatter, Charleston Bump - Deep Coral Priority Areas - Nancy Foster - (2006), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 30x30 meter cell size representing the backscatter intensity of the Charleston Bump off of the South Atlantic Bight,...

  18. Pig model of chronic myocardial ischemia and its investigation by ultrasonic integrated backscatter and Doppler tissue imaging

    Institute of Scientific and Technical Information of China (English)

    XU Jing; ZHAO Bao-zhen; WANG Zhong; GU Jun-yan; LU Shi-ping

    2004-01-01

    Objective: To construct an animal model of chronic ischemic myocardium, and evaluate it by ultrasonic integrated backscatter (IBS) and Doppler tissue imaging (DTI). Methods: An Ameroid constrictor was placed around the porcine left circumflex coronary artery (LCX). The calibrated average image intensity ( % AII), cyclic variation of IBS(CVIB), transmural gradient index (TGI) of CVIB in lateral- posterior wall (LPW), and DTI spectrum of LPW in left ventricular papillary muscle level short axis view (LVPM-SAM) and apical four chamber view (AP-4CV) at normal state, 2, 4,6 and 8 weeks postoperatively were measured. Results: Normal %AII, CVIB and TGI were 2.29 ± 0.32, 9.69 ± 2.22dB and 0.22 ± 0.08, respectively. The % AII increased gradually postoperatively. The CVIB decreased also gradually, and the decrease was higher in subepicardium than in subendocardium. Most of TGI decrease occurred from 2 to 4 weeks postoperatively and became zero at 8 weeks (P < O. 01 ); Normal Vs (peak systolic velocity) of AP-4CV was higher than that of LVPM-SAM ( P < 0.01 ). VE (peak early diastolic velocity) of AP-4CV was lower than that of LVPM-SAM ( P < 0.05). Vs and VE were all decreased after operation ( P < 0.01 ). The decrease of Vs in AP-4CV was greater than that in LVPM-SAM.Conclusion: The pathological changes of the myocardium in human ischemic heart disease (IHD) are similar to that of Ameriod model. IBS and DTI can detect echo changes and ventricular wall motion in chronic ischemic myocardium, and provide more information for clinical investigation and treatment of IHD.

  19. Transmission Electron Microscopy Physics of Image Formation

    CERN Document Server

    Kohl, Helmut

    2008-01-01

    Transmission Electron Microscopy: Physics of Image Formation presents the theory of image and contrast formation, and the analytical modes in transmission electron microscopy. The principles of particle and wave optics of electrons are described. Electron-specimen interactions are discussed for evaluating the theory of scattering and phase contrast. Also discussed are the kinematical and dynamical theories of electron diffraction and their applications for crystal-structure analysis and imaging of lattices and their defects. X-ray microanalysis and electron energy-loss spectroscopy are treated as analytical methods. Specimen damage and contamination by electron irradiation limits the resolution for biological and some inorganic specimens. This fifth edition includes discussion of recent progress, especially in the area of aberration correction and energy filtering; moreover, the topics introduced in the fourth edition have been updated. Transmission Electron Microscopy: Physics of Image Formation is written f...

  20. Electron backscatter diffraction study of deformation and recrystallization textures of individual phases in a cross-rolled duplex steel

    International Nuclear Information System (INIS)

    The evolution of microstructure and texture during cross-rolling and annealing was investigated by electron backscatter diffraction in a ferritic–austenitic duplex stainless steel. For this purpose an alloy with nearly equal volume fraction of the two phases was deformed by multi-pass cross-rolling process up to 90% reduction in thickness. The rolling and transverse directions were mutually interchanged in each pass by rotating the sample by 90° around the normal direction. In order to avoid deformation induced phase transformation and dynamic strain aging, the rolling was carried out at an optimized temperature of 898 K (625 °C) at the warm-deformation range. The microstructure after cross warm-rolling revealed a lamellar structure with alternate arrangement of the bands of two phases. Strong brass and rotated brass components were observed in austenite in the steel after processing by cross warm-rolling. The ferrite in the cross warm-rolling processed steel showed remarkably strong RD-fiber (RD//< 011 >) component (001)< 011 >. The development of texture in the two phases after processing by cross warm-rolling could be explained by the stability of the texture components. During isothermal annealing of the 90% cross warm-rolling processed material the lamellar morphology was retained before collapse of the lamellar structure to the mutual interpenetration of the phase bands. Ferrite showed recovery resulting in annealing texture similar to the deformation texture. In contrast, the austenite showed primary recrystallization without preferential orientation selection leading to the retention of deformation texture. The evolution of deformation and annealing texture in the two phases of the steel was independent of one another. - Highlights: • Effect of cross warm-rolling on texture formation is studied in duplex steel. • Brass texture in austenite and (001)<110 > in ferrite are developed. • Ferrite shows recovery during annealing retaining the (001

  1. NOAA TIFF Image - 8m Backscatter Mosaic, W00221-222 USVI 2012, Seafloor Characterization of the US Caribbean - Nancy Foster - M-I907-NF-12 (2012), UTM 20N NAD83 (NCEI Accession 0131856)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 8 meter resolution backscatter mosaic of of a sharply sloping swath of the St. John Shelf, south of NE Reserve, offshore of Fajardo, Puerto...

  2. NOAA TIFF Image - 1 m Backscatter Mosaic of the St. John Shelf, U.S. Virgin Islands, Project NF-10-03, 2010, UTM 20 WGS84 (NCEI Accession 0131854)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the St. John Shelf, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team, in collaboration...

  3. NOAA TIFF Image - 4m Backscatter Mosaic, Puerto Rico 2013, Escollo Grappler Seamount, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-13-2 USVI (2013), UTM 20N NAD83 (NCEI Accession 0131855)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 4 meter resolution backscatter mosaic of a seamount/bank East of Fajardo, Puerto Rico. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  4. NOAA TIFF Image - 1m Backscatter Mosaic, Puerto Rico 2013, Northeast Reserve, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-13-2 USVI, UTM 20N NAD83 (NCEI Accession 0131855)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the bathymetry of a reef shelf/bank and the steep slopes and canyons of the NE Reserve, offshore of...

  5. NOAA TIFF Image - 1m Backscatter Mosaic, W00221-222 USVI 2012, Seafloor Characterization of the US Caribbean - Nancy Foster - M-I907-NF-12 (2012), UTM 20N NAD83 (NCEI Accession 0131856)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the bathymetry of a reef shelf/bank and the steep slopes and canyons of the NE Reserve, offshore of...

  6. NOAA TIFF Image - 8m Backscatter Mosaic, Puerto Rico 2013, Northeast Reserve, Haystack Seamount, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-13-2 USVI (2013), UTM 20N NAD83 (NCEI Accession 0131855)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents an 8 meter resolution backscatter mosaic of a seamount/bank east of Fajardo, Puerto Rico. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  7. NOAA TIFF Image - 8m Backscatter Mosaic, Puerto Rico 2013, Vieques, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-13-2 USVI (2013), UTM 20N NAD83 (NCEI Accession 0131855)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents an 8 meter resolution backscatter mosaic of a reef shelf/bank south of Vieques, Puerto Rico. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  8. NOAA TIFF Image - 1 m Backscatter Mosaic of Abrir La Sierra Bank, PR (2007) collected using a Kongsberg EM 1002 (95 kHz) multibeam echosounder (NCEI Accession 0131853)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the Abrir La Sierra Bank off the coast of western Puerto Rico, collected using a Kongsberg EM 1002...

  9. NOAA TIFF Image - 1m Backscatter Mosaic, W00221-222 USVI 2012, Seafloor Characterization of the US Caribbean - Nancy Foster - M-I907-NF-12 (2012), UTM 20N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the bathymetry of a reef shelf/bank and the steep slopes and canyons of the NE Reserve, offshore of...

  10. NOAA TIFF Image - 8m Backscatter Mosaic, W00221-222 USVI 2012, Seafloor Characterization of the US Caribbean - Nancy Foster - M-I907-NF-12 (2012), UTM 20N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 8 meter resolution backscatter mosaic of of a sharply sloping swath of the St. John Shelf, south of NE Reserve, offshore of Fajardo, Puerto...

  11. NOAA TIFF Image - 1m Backscatter Mosaic, Puerto Rico 2013, Vieques, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-13-2 USVI, UTM 20N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the bathymetry of a reef shelf/bank south of Vieques, Puerto Rico. NOAA's NOS/NCCOS/CCMA...

  12. NOAA TIFF Image - 1m Backscatter Mosaic, Puerto Rico 2013, Vieques, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-13-2 USVI, UTM 20N NAD83 (NCEI Accession 0131855)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the bathymetry of a reef shelf/bank south of Vieques, Puerto Rico. NOAA's NOS/NCCOS/CCMA...

  13. NOAA TIFF Image - 1 m Backscatter Mosaic of the Virgin Passage and the St. John Shelf, U.S. Virgin Islands, Project NF-10-03, 2010, UTM 20 WGS84 (NCEI Accession 0131854)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the Virgin Passage in the US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  14. NOAA TIFF Image - 1 m Backscatter Mosaic of an offshore portion of the NPS's Virgin Islands Coral Reef National Monument, south of St. John, US Virgin Islands, Project NF-05-05, 2005, UTM 20 WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of an offshore portion of the NPS's Virgin Islands Coral Reef National Monument, south of St. John, US...

  15. NOAA TIFF Image - 8m Backscatter Mosaic, Puerto Rico 2013, Northeast Reserve, Haystack Seamount, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-13-2 USVI (2013), UTM 20N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents an 8 meter resolution backscatter mosaic of a seamount/bank east of Fajardo, Puerto Rico. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  16. NOAA TIFF Image - 1 m Backscatter Mosaic of Abrir La Sierra Bank, PR (2007) collected using a SeaBat Reson 8124 (200 kHz) multibeam echosounder (NCEI Accession 0131853)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the Abrir La Sierra Bank off the coast of western Puerto Rico, collected using a SeaBat Reson 8124...

  17. NOAA TIFF Image - 1m Backscatter Mosaic, Puerto Rico 2013, Northeast Reserve, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-13-2 USVI, UTM 20N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the bathymetry of a reef shelf/bank and the steep slopes and canyons of the NE Reserve, offshore of...

  18. NOAA TIFF Image - 4m Backscatter Mosaic, Puerto Rico 2013, Escollo Grappler Seamount, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-13-2 USVI (2013), UTM 20N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 4 meter resolution backscatter mosaic of a seamount/bank East of Fajardo, Puerto Rico. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  19. NOAA TIFF Image - 2m Backscatter Mosaic, W00217 USVI 2011, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-11-1 (2011), UTM 20N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 2 meter resolution backscatter mosaic of a broad bank south of St. Thomas, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  20. NOAA TIFF Image - 1m Backscatter Mosaic, Puerto Rico 2012-2013, Northeast Reserve, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-13-2 USVI, UTM 20N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the bathymetry of a reef shelf/bank and the steep slopes and canyons of the NE Reserve, offshore of...

  1. NOAA TIFF Image - 2m Backscatter Mosaic, W00217 USVI 2011, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-11-1 (2011), UTM 20N NAD83 (NCEI Accession 0131858)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 2 meter resolution backscatter mosaic of a broad bank south of St. Thomas, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  2. NOAA TIFF Image - 3 m Backscatter Mosaic of the north shore of St. Croix, U.S. Virgin Islands, Project NF-06-03, 2006, UTM 20 WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 3 meter resolution backscatter mosaic of the north shore of St. Croix, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  3. NOAA TIFF Image- 0.5 meter Backscatter Mosaic of Grammanik Bank - East (St. Thomas), US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83 (NCEI Accession 0131860)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of Grammanik Bank, south of St. Thomas, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography Team,...

  4. NOAA TIFF Image- 0.5 meter Backscatter Mosaic of Mid Shelf Reef (St. Thomas), US Virgin Islands, Project NF-05-05, 2005, UTM 20 NAD83 (NCEI Accession 0131860)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the Mid Shelf Reef south of St. Thomas, US Virgin IslandsNOAA's NOS/NCCOS/CCMA Biogeography Team,...

  5. NOAA TIFF Image - 1 m Backscatter Mosaic of the Virgin Passage and the St. John Shelf, U.S. Virgin Islands, Project NF-10-03, 2010, UTM 20 WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the Virgin Passage in the US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  6. NOS TIFF Image, St. Croix, U.S. Virgin Islands, 2006, 3 m Backscatter Mosaic of the North Shore of Project NF-06-03, UTM 20 WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 3 meter resolution backscatter mosaic of the north shore of St. Croix, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  7. Coherent Electron Source for Ultrafast Electron Diffraction and Imaging

    Directory of Open Access Journals (Sweden)

    Xu C.

    2013-03-01

    Full Text Available We numerically investigate the suitability of photoexcited nanotips as a source of coherent femtosecond single electron pulses for ultrafast surface-sensitive electron diffraction and non-destructive imaging with low-energy electrons. The experimental parameters for realizing hundred femtosecond time resolution are identified by evaluating the effects of vacuum dispersion and beam divergence on the temporal broadening of the electron wave packet during its propagation to the sample.

  8. Gravitational Laser Back-Scattering

    OpenAIRE

    Novaes, S. F.; Spehler, D.

    1993-01-01

    A possible way of producing gravitons in the laboratory is investigated. We evaluate the cross section electron + photon $\\rightarrow$ electron + graviton in the framework of linearized gravitation, and analyse this reaction considering the photon coming either from a laser beam or from a Compton back-scattering process.

  9. Merging of image data in electron crystallography.

    Science.gov (United States)

    Arheit, Marcel; Castaño-Diéz, Daniel; Thierry, Raphaël; Abeyrathne, Priyanka; Gipson, Bryant R; Stahlberg, Henning

    2013-01-01

    Electron crystallography of membrane proteins uses cryo-transmission electron microscopy to record images and diffraction patterns of frozen-hydrated 2D crystals. Each two-dimensional (2D) crystal is only imaged once, at one specific tilt angle, and the recorded images can be automatically processed with the 2dx/MRC software package. Processed image data from non-tilted and tilted 2D crystals then need to be merged into a 3D reconstruction of the membrane protein structure. We here describe the process of the 3D merging, using the 2dx software system.

  10. Electronic imaging of the human body.

    OpenAIRE

    Vannier, M. W.; Yates, R. E.; Whitestone, J.

    1992-01-01

    The Human Engineering Division of the Armstrong Laboratory (USAF); the Mallinckrodt Institute of Radiology; the Washington University School of Medicine; and the Lister-Hill National Center for Biomedical Communication, National Library of Medicine are sponsoring a working group on electronic imaging of the human body. Electronic imaging of the surface of the human body has been pursued and developed by a number of disciplines including radiology, forensics, surgery, engineering, medical educ...

  11. Electron image reconstruction of helical protein assemblies

    International Nuclear Information System (INIS)

    The analysis of projections of large ordered biological systems obtained by electron microscopy of negatively stained specimens is described. The biological structures amenable to this approach are constructed from a large number of identical protein molecules, which are arranged according to helical symmetry. Electron images of these structures generally contain sufficient information in order to calculate a three-dimensional density map. (Auth.)

  12. Averaging of Backscatter Intensities in Compounds

    Science.gov (United States)

    Donovan, John J.; Pingitore, Nicholas E.; Westphal, Andrew J.

    2002-01-01

    Low uncertainty measurements on pure element stable isotope pairs demonstrate that mass has no influence on the backscattering of electrons at typical electron microprobe energies. The traditional prediction of average backscatter intensities in compounds using elemental mass fractions is improperly grounded in mass and thus has no physical basis. We propose an alternative model to mass fraction averaging, based of the number of electrons or protons, termed “electron fraction,” which predicts backscatter yield better than mass fraction averaging. PMID:27446752

  13. Electron accelerating unit for streak image tubes

    Indian Academy of Sciences (India)

    Fangke Zong; Qinlao Yang; Houzhi Cai; Li Gu; Xiang Li; Jingjin Zhang

    2015-12-01

    An electron accelerating unit is proposed for use in streak image tubes (SITs). An SIT with this new accelerating unit was simulated using the Monte Carlo method. The simulation results show that the accelerating unit improves both the spatial and temporal resolution. Compared to a traditional SIT, the transit time spread for electrons in the cathode-to-mesh region is reduced from 247 to 162 fs, the line width of the electron beam on the image surface is reduced from 42.7 to 26.1 m, and the temporal resolution is improved from 515 to 395 fs.

  14. Electron Paramagnetic Resonance Imaging: 1. CW-EPR Imaging

    Indian Academy of Sciences (India)

    2016-07-01

    Twentieth century bore witness to remarkable scientists whohave advanced our understanding of the brain. Among them,EPR (Electron Paramagnetic Resonance) imaging is particularlyuseful in monitoring hypoxic zones in tumors which arehighly resistant to radiation and chemotherapeutic treatment.This first part of the article covers aspects of CW(continuous wave) imaging with details of FT (pulsed FourierTransform)-EPR imaging covered in Part 2, to be publishedin the next issue of Resonance.

  15. 2D microwave imaging reflectometer electronics

    Energy Technology Data Exchange (ETDEWEB)

    Spear, A. G.; Domier, C. W., E-mail: cwdomier@ucdavis.edu; Hu, X.; Muscatello, C. M.; Ren, X.; Luhmann, N. C. [Electrical and Computer Engineering, University of California, Davis, California 95616 (United States); Tobias, B. J. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2014-11-15

    A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.

  16. Factors influencing the austenite stability during tensile testing of Quenching and Partitioning steel determined via in-situ Electron Backscatter Diffraction

    Energy Technology Data Exchange (ETDEWEB)

    De Knijf, Dorien, E-mail: dorien.deknijf@ugent.be [Department of Materials Science and Engineering, Ghent University, Technologiepark 903, B-9052 Zwijnaarde (Ghent) (Belgium); Föjer, Cecilia [ArcelorMittal Global R& D Gent, President J.F. Kennedylaan 3, B-9060 Zelzate (Belgium); Kestens, Leo A.I. [Department of Materials Science and Engineering, Ghent University, Technologiepark 903, B-9052 Zwijnaarde (Ghent) (Belgium); Department Material Science and Engineering, TUDelft, Mekelweg 2, NL-2628 CD Delft (Netherlands); Petrov, Roumen [Department of Materials Science and Engineering, Ghent University, Technologiepark 903, B-9052 Zwijnaarde (Ghent) (Belgium); ArcelorMittal Global R& D Gent, President J.F. Kennedylaan 3, B-9060 Zelzate (Belgium)

    2015-06-25

    The effect of the microstructural characteristics of retained austenite on its transformation stability in steel after Quenching and Partitioning (Q&P) was studied via interrupted tensile tests and Electron Backscatter Diffraction measurements on a pre-determined zone of a micro-tensile test sample. The evolution of the retained austenite fraction was obtained as a function of the plastic strain. The dependence of the austenite transformation stability on the corresponding grain size, morphology, and local crystallographic orientation was discussed. Furthermore, the importance of the parameters on the austenite stability was analysed and it was shown that the austenite grains rotated, in addition to being transformed, constituting therefore an additional contribution to the ductility of Q&P steel.

  17. Comparative Characterization of InGaN/GaN Multiple Quantum Wells by Transmission Electron Microscopy, X-Ray Diffraction and Rutherford Backscattering

    Institute of Scientific and Technical Information of China (English)

    ZHOU Sheng-Qiang; WU Ming-Fang; YAO Shu-De; ZHANG Guo-Yi

    2005-01-01

    @@ The composition, elastic strain and structural defects of InGaN/GaN multiple quantum wells (MQWs) are comparatively investigated by using x-ray diffraction (XRD), transmission electron microscopy and Rutherford backscattering/channelling. The InGaN well layers are fully strained on GaN, i.e. the degree of relaxation is zero.The multilayered structure has a clear defined periodic thickness and abrupt interfaces. The In composition is deduced by XRD simulation. We show how the periodic structure, the In composition, the strain status and the crystalline quality of the InGaN/GaN MQWs can be determined and cross-checked by various techniques.

  18. Characterization of local strain/stress in copper through-silicon via structures using synchrotron x-ray microdiffraction, electron backscattered diffraction and nonlinear thermomechanical model

    International Nuclear Information System (INIS)

    In this study, the thermomechanical characteristics of copper through-silicon via (Cu TSV) structures were studied using synchrotron x-ray microdiffraction, electron backscattered diffraction (EBSD), and nonlinear numerical modeling. The strain and stress distribution in the Si substrate was measured by synchrotron x-ray microdiffraction from the tops of the TSV structures. The strain distribution map in a Cu via was determined from EBSD data by the kernel average misorientation (KAM) method and microstructural characteristics of the Cu via were investigated. The results offered direct evaluation of the local strain and stress induced in the Cu via and its surrounding silicon substrate. A finite element model including nonlinear plastic deformation was built for predicting thermomechanical behaviors of Cu TSV structures. The results show that the stress distribution obtained by finite element modeling is in relatively good agreement with the measurements of synchrotron x-ray microdiffraction and EBSD. (paper)

  19. Electron backscatter diffraction analysis of gold nanoparticles on Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7−δ}

    Energy Technology Data Exchange (ETDEWEB)

    Bochmann, A.; Teichert, S., E-mail: steffen.teichert@fh-jena.de [University of Applied Sciences Jena, Carl Zeiss Promenade 2, Jena 07745 (Germany); Katzer, C.; Schmidl, F. [Friedrich Schiller University Jena, Fürstengraben 1, Jena 07743 (Germany)

    2015-06-07

    It has been shown recently that the incorporation of gold nanoparticles into Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7−δ} enhances the superconducting properties of this material in a significant way. Previous XRD and TEM investigations suggest different crystallographic relations of the gold nanoparticles with respect to the epitaxial Y{sub 1}Ba{sub 2}Cu{sub 3}O{sub 7−δ}. Here, detailed investigations of the crystal orientations for a large ensemble of gold nanoparticles with electron backscatter diffraction are reported. The average size of the gold nanoparticles is in the range of 60 nm–80 nm. We identified five different types of heteroepitaxial relationships between the gold nanoparticles and the superconductor film, resulting in complex pole figures. The observed different types of crystallographic orientations are discussed based on good lattice matching and the formation of low energy interfaces.

  20. Improvement of depth resolution and detection efficiency by control of secondary-electrons in single-event three-dimensional time-of-flight Rutherford backscattering spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Abo, Satoshi, E-mail: s-abo@stec.es.osaka-u.ac.jp [Graduate School of Engineering Science, Osaka University, 1-3, Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Hamada, Yasuhisa [Graduate School of Engineering Science, Osaka University, 1-3, Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Seidl, Albert [Graduate School of Engineering Science, Osaka University, 1-3, Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Engineering Science and Industrial Design, Magdeburg-Stendal University of Applied Sciences, Breitscheidstraße 2, 39114 Magdeburg (Germany); Wakaya, Fujio; Takai, Mikio [Graduate School of Engineering Science, Osaka University, 1-3, Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)

    2015-04-01

    An improvement of a depth resolution and a detection efficiency in single-event three-dimensional time-of-flight (TOF) Rutherford backscattering spectrometry (RBS) is discussed on both simulation and experiment by control of secondary electron trajectories using sample bias voltage. The secondary electron, used for a start signal in single-event TOF-RBS, flies more directly to a secondary electron detector with the positive sample bias voltage of several tens of volt than that without sample bias voltage in the simulation. The simulated collection efficiency of the secondary electrons also increases with the positive sample bias voltage of several tens of volt. These simulation results indicate the possibility of a smaller depth resolution and a shorter measurement time in single-event TOF-RBS with positive sample bias voltage. The measurement time for the Pt-stripe sample using single-event three-dimensional TOF-RBS with the sample bias voltage of +100 V is 65% shorter than that without sample bias voltage, resulting in a less sample damage by a probe beam. The depth resolution for the Pt stripes under the 50-nm-thick SiO{sub 2} cover-layer with the sample bias voltage of +100 V is 4 nm smaller than that without sample bias voltage. Positive sample bias voltage improves the depth resolution and the detection efficiency in single-event three-dimensional TOF-RBS without an influence on the beam focusing.

  1. Study of Pd--Ta on Si(100) using Auger electron spectroscopy, Rutherford backscattering spectrometry, and variable energy positron annihilation

    Energy Technology Data Exchange (ETDEWEB)

    van der Kolk, G.J.; Kuiper, A.E.T.; Duchateau, J.P.W.B.; Willemsen, M.; Nielsen, B.; Lynn, K.G.

    1989-05-01

    The applicability of Pd/sub x/Ta/sub 1-//sub x/ as a diffusion barrier on Si has been investigated. For this purpose Pd/sub x/Ta/sub 1-//sub x/ films of 200-nm thickness (x ranges from 0 to 1) were deposited on Si(100), and the reaction between overlayer and substrate was studied as a function of temperature. Interaction was found to occur at temperatures increasing with the Ta content. The as-deposited Pd/sub x/Ta/sub 1-//sub x/ films with 0.2less than or equal toxless than or equal to0.6 were found to be amorphous. The amorphous phase had a higher reaction temperature than the crystalline one, causing a discontinuous step in the reaction temperature. Rutherford backscattering spectrometry spectra revealed that for the Pd-rich compositions, first a stoichiometric Pd/sub 2/Si layer formed underneath a pure Ta layer. At higher temperatures TaSi/sub 2/ formed at the surface. For Ta-rich compositions Pd/sub 2/Si formed first as well; however, the reaction temperature was so high that Pd/sub 2/Si grains formed in a Si matrix. The defect density of the Ta layer, which remained after outdiffusion of Pd, was investigated using variable energy positron annihilation. The defect concentration is very high, as deduced from the trapped positron fraction. A model is presented that describes the composition dependence of the reaction temperature.

  2. On line ultrasonic integrated backscatter

    International Nuclear Information System (INIS)

    A new equipment for on-line evaluation of index based on two-dimensional integrated backscatter from ultrasonic images is described. The new equipment is fully integrated into a B-mode ultrasonic apparatus which provides a simultaneous display of conventional information together with parameters of tissue characterization. The system has been tested with a backscattering model of microbubbles in polysaccharide solution, characterized by a physiological exponential time decay. An exponential fitting to the experimental data was performed which yielded r=0.95

  3. Assessment of Multiple Delamination in Laminated Composites for Aircrafts using X-ray Backscattering

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Noh Yu [College of Medicine, Hanyang University, Cheonan (Korea, Republic of)

    2010-02-15

    A Compton X-ray backscatter technique has been developed to quantitatively assess impact damage in quasi-isotropic laminated composites made by a drop-weight tester. X-ray backscatter imaging system with a slit-type camera is constructed to obtain a cross-sectional profile of impact-damaged laminated composites from the electron-density variation of the cross section. A nonlinear scattering model based on Boltsman equation is introduced to compute Compton X-ray backscattering field for the defect assessment. An adaptive filter is also used to reduce noises from many sources including quantum noise and irregular distributions of fibers and matrix in composites. Delaminations masked or distorted by the first delamination are detected and characterized effectively by the Compton X-ray backscatter technique, both in width and location, by application of error minimization algorithm

  4. A reconfigurable image tube using an external electronic image readout

    Science.gov (United States)

    Lapington, J. S.; Howorth, J. R.; Milnes, J. S.

    2005-08-01

    We have designed and built a sealed tube microchannel plate (MCP) intensifier for optical/NUV photon counting applications suitable for 18, 25 and 40 mm diameter formats. The intensifier uses an electronic image readout to provide direct conversion of event position into electronic signals, without the drawbacks associated with phosphor screens and subsequent optical detection. The Image Charge technique is used to remove the readout from the intensifier vacuum enclosure, obviating the requirement for additional electrical vacuum feedthroughs and for the readout pattern to be UHV compatible. The charge signal from an MCP intensifier is capacitively coupled via a thin dielectric vacuum window to the electronic image readout, which is external to the sealed intensifier tube. The readout pattern is a separate item held in proximity to the dielectric window and can be easily detached, making the system easily reconfigurable. Since the readout pattern detects induced charge and is external to the tube, it can be constructed as a multilayer, eliminating the requirement for narrow insulator gaps and allowing it to be constructed using standard PCB manufacturing tolerances. We describe two readout patterns, the tetra wedge anode (TWA), an optimized 4 electrode device similar to the wedge and strip anode (WSA) but with a factor 2 improvement in resolution, and an 8 channel high speed 50 ohm device, both manufactured as multilayer PCBs. We present results of the detector imaging performance, image resolution, linearity and stability, and discuss the development of an integrated readout and electronics device based on these designs.

  5. Influence of orbital symmetry on diffraction imaging with rescattering electron wave packets

    CERN Document Server

    Pullen, M G; Le, A -T; Baudisch, M; Sclafani, M; Pires, H; Schröter, C D; Ullrich, J; Moshammer, R; Pfeifer, T; Lin, C D; Biegert, J

    2016-01-01

    The ability to directly follow and time resolve the rearrangement of the nuclei within molecules is a frontier of science that requires atomic spatial and few-femtosecond temporal resolutions. While laser induced electron diffraction can meet these requirements, it was recently concluded that molecules with particular orbital symmetries (such as {\\pi}g) cannot be imaged using purely backscattering electron wave packets without molecular alignment. Here, we demonstrate, in direct contradiction to these findings, that the orientation and shape of molecular orbitals presents no impediment for retrieving molecular structure with adequate sampling of the momentum transfer space. We overcome previous issues by showcasing retrieval of the structure of randomly oriented O2 and C2H2 molecules, with {\\pi}g and {\\pi}u symmetries, respectively, and where their ionisation probabilities do not maximise along their molecular axes. While this removes a serious bottleneck for laser induced diffraction imaging, we find unexpec...

  6. New method for the determination of the correction function of a hemisperical electron analyser based on elastic electron images

    International Nuclear Information System (INIS)

    Highlights: • Determination of correction function of a hemispherical analyzer (HSA). • Visualization of analysis area using elastic backscattered electron images. • Dependence of analysis area and transmission function with the kinetic energy. • Efficiency of these functions for quantitative interpretations of XPS. • Description of the general methodology to use these functions. - Abstract: The correction function of a hemispherical analyzer (HSA) is determined for quantitative interpretations of electron spectroscopy. In this way, electron elastic images are performed using a scanning electron gun. This new method allowed the determination of the analysis area A(EK) of a HSA for the first time. An important result is the dependence of this analysis area on the electron kinetic energy EK. Indeed, results show that A(EK) varies as EK−1.2 regardless of the spectrometer configuration. This parameter is different from the so-called transmission function and must be taken into account for quantitative interpretation. Moreover, the transmission function T(EK) is also determined in this work and varies as a power function EKx where x is a fitting parameter which depends only on the width in the energy dispersive direction of the hemisphere entrance slit. These two apparatus functions are then validated thanks to XPS measurements by comparing results obtained on two different Ag surfaces. Then a general methodology to use these functions is given

  7. New method for the determination of the correction function of a hemisperical electron analyser based on elastic electron images

    Energy Technology Data Exchange (ETDEWEB)

    Mahjoub, Mohamed Aymen [Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6602, IP, F-63171 Aubière (France); Monier, Guillaume, E-mail: guillaume.monier@univ-bpclermont.fr [Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6602, IP, F-63171 Aubière (France); Robert-Goumet, Christine; Bideux, Luc; Gruzza, Bernard [Clermont Université, Université Blaise Pascal, Institut Pascal, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6602, IP, F-63171 Aubière (France)

    2014-12-15

    Highlights: • Determination of correction function of a hemispherical analyzer (HSA). • Visualization of analysis area using elastic backscattered electron images. • Dependence of analysis area and transmission function with the kinetic energy. • Efficiency of these functions for quantitative interpretations of XPS. • Description of the general methodology to use these functions. - Abstract: The correction function of a hemispherical analyzer (HSA) is determined for quantitative interpretations of electron spectroscopy. In this way, electron elastic images are performed using a scanning electron gun. This new method allowed the determination of the analysis area A(E{sub K}) of a HSA for the first time. An important result is the dependence of this analysis area on the electron kinetic energy E{sub K}. Indeed, results show that A(E{sub K}) varies as E{sub K}{sup −1.2} regardless of the spectrometer configuration. This parameter is different from the so-called transmission function and must be taken into account for quantitative interpretation. Moreover, the transmission function T(E{sub K}) is also determined in this work and varies as a power function E{sub K}{sup x} where x is a fitting parameter which depends only on the width in the energy dispersive direction of the hemisphere entrance slit. These two apparatus functions are then validated thanks to XPS measurements by comparing results obtained on two different Ag surfaces. Then a general methodology to use these functions is given.

  8. A novel imaging technique based on the spatial coherence of backscattered waves: demonstration in the presence of acoustical clutter

    Science.gov (United States)

    Dahl, Jeremy J.; Pinton, Gianmarco F.; Lediju, Muyinatu; Trahey, Gregg E.

    2011-03-01

    In the last 20 years, the number of suboptimal and inadequate ultrasound exams has increased. This trend has been linked to the increasing population of overweight and obese individuals. The primary causes of image degradation in these individuals are often attributed to phase aberration and clutter. Phase aberration degrades image quality by distorting the transmitted and received pressure waves, while clutter degrades image quality by introducing incoherent acoustical interference into the received pressure wavefront. Although significant research efforts have pursued the correction of image degradation due to phase aberration, few efforts have characterized or corrected image degradation due to clutter. We have developed a novel imaging technique that is capable of differentiating ultrasonic signals corrupted by acoustical interference. The technique, named short-lag spatial coherence (SLSC) imaging, is based on the spatial coherence of the received ultrasonic wavefront at small spatial distances across the transducer aperture. We demonstrate comparative B-mode and SLSC images using full-wave simulations that include the effects of clutter and show that SLSC imaging generates contrast-to-noise ratios (CNR) and signal-to-noise ratios (SNR) that are significantly better than B-mode imaging under noise-free conditions. In the presence of noise, SLSC imaging significantly outperforms conventional B-mode imaging in all image quality metrics. We demonstrate the use of SLSC imaging in vivo and compare B-mode and SLSC images of human thyroid and liver.

  9. Application of particle-induced X-ray emission, backscattering spectrometry and scanning electron microscopy in the evaluation of orthodontic materials

    International Nuclear Information System (INIS)

    The focus of this investigation was on orthodontic materials used in the manufacture of dental brackets. The properties of these dental materials are subjected to various physical parameters such as elongation, yield strength and elasticity that justify their application. In turn, these parameters depend on the quantitative elemental concentration distribution (QECD) in the materials used in the manufacture. For compositional analysis, proton-induced X-ray emission (PIXE), backscatter spectrometry (BS) and scanning electron microscopy (SEM) were applied. QECD analysis was performed to correlate the physical parameters with the composition and to quantify imperfections in the materials. PIXE and BS analyses were performed simultaneously with a 3 MeV proton beam while electrons accelerated at 25 keV were used for the SEM analysis. From the QECDs it was observed that: (1) the major elements Cr, Fe and Ni were homogeneously distributed in the orthodontic plate; (2) the distribution of Mo and O correlated with one another; (3) there was a spread of Cr around regions of high C concentration; and, (4) areas of high concentrations of Mo and O corresponded to a decrease in C concentrations. Elemental concentration correlations are shown to indicate the similarities and differences in the ease of formation of phases, based on the tangent of linearity. (author)

  10. Oriented Nucleation of both Ge-Fresnoite and Benitoite/BaGe4O9 during the Surface Crystallisation of Glass Studied by Electron Backscatter Diffraction.

    Science.gov (United States)

    Wisniewski, Wolfgang; Patschger, Marek; Murdzheva, Steliana; Thieme, Christian; Rüssel, Christian

    2016-01-01

    Two glasses of the compositions 2 BaO - TiO2 - 2.75 GeO2 and 2 BaO - TiO2 -3.67 GeO2 (also known as BTG55) are annealed at temperatures from 680 to 970 °C to induce surface crystallization. The resulting samples are analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) including electron backscatter diffraction (EBSD). Ge-Fresnoite (Ba2TiGe2O8, BTG) is observed at the immediate surface of all samples and oriented nucleation is proven in both compositions. After a very fast kinetic selection, the crystal growth of BTG into the bulk occurs via highly oriented dendrites where the c-axes are oriented perpendicular to the surface. The growth of this oriented layer is finally blocked by dendritc BTG originating from bulk nucleation. The secondary phases BaTiGe3O9 (benitoite) and BaGe4O9 are also identified near the surface by XRD and localized by EBSD which additionally indicates orientation preferences for these phases. This behaviour is in contrast with previous reports from the Ba2TiSi2O8 as well as the Sr2TiSi2O8 systems. PMID:26853738

  11. 极化SAR影像弱散射地物统计分类%Statistical classification of weak backscattering scatterers of PolSAR image

    Institute of Scientific and Technical Information of China (English)

    赵伶俐; 杨杰; 李平湘; 郎丰铠; 史磊

    2013-01-01

    The Wishart classifier has the major issue of drastically favoring the intensity over the polarimetric information, so the weak backscattering targets such as water, road, bare soil and shadow in Polariemtric Synthetic Aperture Radar (PolSAR) image are hard to be made fine distinction. This paper proposed an unsupervised statistical classifier of the weak backscattering scatterers based on H-α target decomposition and hypothesis test. Likelihood ratio test is used as a distance measure to compare the similarity of a pixel and class centers. Pixels with small similarity are rejected according to the first type error and the distribution of the test statistics to reduce the effect on classification. The others pixels being not rejected are assigned to the class with the smallest statistics. The experiential results using E-SAR L band and Radarsat-2 C band quad polarimetric image demonstrate that this algorithm making advantage of the polarimetric information, improves the classification accuracy of the weak backscattering scatterers greatly.%针对Wishart分类器对功率具有较强的依赖性,不易区分极化SAR影像上水体、道路、裸土、阴影等弱后向散射地物的问题,提出一种利用极化目标分解和假设检验的弱散射地物统计分类方法.即在H-α初始化的基础上,使用似然比检验得出像元与每个类中心的相似性,并将其作为像元与类中心的距离测度.根据第一类错误概率和统计量的概率分布,将相似性很小的强散射点归为拒绝类,减少对分类的影响;对不能显著拒绝的像元归入具有最小统计量的类别中.通过使用E-SAR L波段和Radarsat-2 C波段全极化数据进行实验,结果表明本文方法有利于弱散射地物极化信息的利用,能够实现水体、道路、裸露的土壤和阴影等的精确分类.

  12. Influence of orbital symmetry on diffraction imaging with rescattering electron wave packets.

    Science.gov (United States)

    Pullen, M G; Wolter, B; Le, A-T; Baudisch, M; Sclafani, M; Pires, H; Schröter, C D; Ullrich, J; Moshammer, R; Pfeifer, T; Lin, C D; Biegert, J

    2016-01-01

    The ability to directly follow and time-resolve the rearrangement of the nuclei within molecules is a frontier of science that requires atomic spatial and few-femtosecond temporal resolutions. While laser-induced electron diffraction can meet these requirements, it was recently concluded that molecules with particular orbital symmetries (such as πg) cannot be imaged using purely backscattering electron wave packets without molecular alignment. Here, we demonstrate, in direct contradiction to these findings, that the orientation and shape of molecular orbitals presents no impediment for retrieving molecular structure with adequate sampling of the momentum transfer space. We overcome previous issues by showcasing retrieval of the structure of randomly oriented O2 and C2H2 molecules, with πg and πu symmetries, respectively, and where their ionization probabilities do not maximize along their molecular axes. While this removes a serious bottleneck for laser-induced diffraction imaging, we find unexpectedly strong backscattering contributions from low-Z atoms. PMID:27329236

  13. Influence of orbital symmetry on diffraction imaging with rescattering electron wave packets

    Science.gov (United States)

    Pullen, M. G.; Wolter, B.; Le, A. -T.; Baudisch, M.; Sclafani, M.; Pires, H.; Schröter, C. D.; Ullrich, J.; Moshammer, R.; Pfeifer, T.; Lin, C. D.; Biegert, J.

    2016-01-01

    The ability to directly follow and time-resolve the rearrangement of the nuclei within molecules is a frontier of science that requires atomic spatial and few-femtosecond temporal resolutions. While laser-induced electron diffraction can meet these requirements, it was recently concluded that molecules with particular orbital symmetries (such as πg) cannot be imaged using purely backscattering electron wave packets without molecular alignment. Here, we demonstrate, in direct contradiction to these findings, that the orientation and shape of molecular orbitals presents no impediment for retrieving molecular structure with adequate sampling of the momentum transfer space. We overcome previous issues by showcasing retrieval of the structure of randomly oriented O2 and C2H2 molecules, with πg and πu symmetries, respectively, and where their ionization probabilities do not maximize along their molecular axes. While this removes a serious bottleneck for laser-induced diffraction imaging, we find unexpectedly strong backscattering contributions from low-Z atoms. PMID:27329236

  14. Spin probes for electron paramagnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    YAN GuoPing; PENG Lei; JIAN ShuangQuan; LI Liang; BOTTLE Steven Eric

    2008-01-01

    Electron paramagnetic resonance imaging (EPRI) is a relatively recent imaging technique, which provides potentially multidimensional imaging of the spatial distribution of paramagnetic species. Thanks to the use of stable spin probes, low frequency EPR imaging has recently allowed the use of large tissue samples or whole animals in vivo in the field of biology and medicine. It is normally necessary to introduce prior intravenous or intramuscular infusion of stable or slowly metabolizable non-toxic water-soluble paramagnetic materials, or stable implantable particulate materials as spin probes into the system. The classification and research progress of spin probes at present were described briefly.Three important potential approaches in water-soluble paramagnetic materials design including deuterated, site-specific and macromolecular conjugated nitroxides were also investigated.

  15. Plastic and elastic strains in short and long cracks in Alloy 600 studied by polychromatic X-ray microdiffraction and electron backscatter diffraction

    International Nuclear Information System (INIS)

    The microscopic strain distributions were studied for stress corrosion cracks produced electrochemically in C-rings of Alloy 600 (0.65 Ni, 0.16 Cr, 0.08 Fe). The strain data were obtained using polychromatic X-ray microdiffraction (PXM) and (in part) by electron back-scatter diffraction (EBSD). PXM was used to measure plastic and elastic strain distributions around the tip of a short crack, along with the changes to the direction and shape of the diffraction spots (ellipticity). For a sample with a short (30 μm) crack, the misorientation map showed a well-defined region of plastic deformation along the grain boundary in advance of the crack tip, extending to the next triple point. For the large crack sample, plastic and elastic stains as well as crystalline order could be measured in high detail with respect to the crack path. However, no correlation between these could be obtained, except for a notable degradation of crystalline order near the crack mouth. A comparable EBSD misorientation map shows strong correlation between misorientation and the crack edges; this may in part reflect the role of sharp edges in the more surface-sensitive approach.

  16. Crystallographic measurement of the β to α phase transformation and δ-hydride precipitation in a laser-welded Zircaloy-2 tube by electron backscattering diffraction

    International Nuclear Information System (INIS)

    Crystallographic measurement of the β to α phase transformation and δ-hydride precipitation in a laser-welded Zircaloy-2 ferrule tube were carried out using an electron backscattering diffraction pattern (EBSP). A basket-weave structure with sub-micron lath width caused by quenching from the β to α phase was observed in the heat-affected and fusion zones, and mainly showed a grain boundary misorientation angle of 60 deg. with an rotation axis. This result is consistent with the Burgers orientation relationship of {1 1 0}β//(0 0 0 1)α and β//α for the β to α phase transformation. The texture of the quenched α' phase was strongly inherited from the original α phase, having a radial (0 0 0 1) basal pole and axial {1 1 2-bar0} textures, even in the fusion zone. The primary hydride habit plane in the welded Zircaloy-2 was (0 0 0 1)α//{1 1 1}δ, matching previously obtained results for recrystallized cladding tubes. In addition to the primary habit plane, secondary habit planes were observed for the other low-index planes {1 0 1-bar0} and {1 0 1-bar1} in the fusion zone. The heterogeneous accumulation of hydrides in the transition zone between heat-affected and unaffected zones was mainly due to the residual stress distribution in the narrow region.

  17. Crystallographic measurement of the β to α phase transformation and δ-hydride precipitation in a laser-welded Zircaloy-2 tube by electron backscattering diffraction

    Science.gov (United States)

    Une, K.; Ishimoto, S.

    2009-06-01

    Crystallographic measurement of the β to α phase transformation and δ-hydride precipitation in a laser-welded Zircaloy-2 ferrule tube were carried out using an electron backscattering diffraction pattern (EBSP). A basket-weave structure with sub-micron lath width caused by quenching from the β to α phase was observed in the heat-affected and fusion zones, and mainly showed a grain boundary misorientation angle of 60° with an rotation axis. This result is consistent with the Burgers orientation relationship of {1 1 0} β//(0 0 0 1) α and β// α for the β to α phase transformation. The texture of the quenched α' phase was strongly inherited from the original α phase, having a radial (0 0 0 1) basal pole and axial {1 1 2¯ 0} textures, even in the fusion zone. The primary hydride habit plane in the welded Zircaloy-2 was (0 0 0 1) α//{1 1 1} δ, matching previously obtained results for recrystallized cladding tubes. In addition to the primary habit plane, secondary habit planes were observed for the other low-index planes {1 0 1¯ 0} and {1 0 1¯ 1} in the fusion zone. The heterogeneous accumulation of hydrides in the transition zone between heat-affected and unaffected zones was mainly due to the residual stress distribution in the narrow region.

  18. Interactions of Y2BaCuO5 particles and the YBCO matrix within melt-textured YBCO samples studied by means of electron backscatter diffraction

    Science.gov (United States)

    Koblischka-Veneva, A.; Koblischka, M. R.; Mücklich, F.; Ogasawara, K.; Murakami, M.

    2005-02-01

    By means of automated electron backscatter diffraction (EBSD) analysis, we studied the local orientations of embedded Y2BaCuO5(211) particles within melt-textured YBa2Cu3Ox (YBCO) samples. On both components, we obtained high-quality Kikuchi patterns, thus allowing the automated mapping of the crystal orientations and a two-phase analysis of the samples. Investigations were performed on a variety of melt-textured YBCO samples. In melt-textured YBCO with (001) orientation, we find that the embedded 211 particles do not have any preferred orientation. The EBSD maps also reveal that at certain orientations of the 211 particles the YBCO growth is not altered. From the obtained EBSD mappings, we can conclude that the formation of small 211 particles will not disturb the YBCO matrix growth, whereas the presence of large 211 particles causes severe changes in the YBCO growth, leading to the formation of subgrains. The EBSD results are presented in the form of local orientation maps and local pole figures.

  19. Imaging Electron Spectrometer (IES) Electron Preprocessor (EPP) Design

    Science.gov (United States)

    Fennell, J. F.; Osborn, J. V.; Christensen, John L. (Technical Monitor)

    2001-01-01

    The Aerospace Corporation developed the Electron PreProcessor (EPP) to support the Imaging Electron Spectrometer (IES) that is part of the RAPID experiment on the ESA/NASA CLUSTER mission. The purpose of the EPP is to collect raw data from the IES and perform processing and data compression on it before transferring it to the RAPID microprocessor system for formatting and transmission to the CLUSTER satellite data system. The report provides a short history of the RAPID and CLUSTER programs and describes the EPP design. Four EPP units were fabricated, tested, and delivered for the original CLUSTER program. These were destroyed during a launch failure. Four more EPP units were delivered for the CLUSTER II program. These were successfully launched and are operating nominally on orbit.

  20. The role of electronic media in shaping the country's image

    Directory of Open Access Journals (Sweden)

    Azel Zhanibek

    2011-07-01

    Full Text Available This article discusses the influence of electronic media in the country to external image of Kazakhstan. Special attention is paid to the experience of various countries in promoting the country's image by electronic media.

  1. Theory of dynamical electron channeling contrast images of near-surface crystal defects

    Energy Technology Data Exchange (ETDEWEB)

    Picard, Y.N., E-mail: yoosuf@andrew.cmu.edu; Liu, M., E-mail: mincongl@andrew.cmu.edu; Lammatao, J., E-mail: jlammmat@andrew.cmu.edu; Kamaladasa, R., E-mail: rkamalad@andrew.cmu.edu; De Graef, M., E-mail: degraef@cmu.edu

    2014-11-15

    This paper describes the dynamical simulation of electron channeling contrast images (ECCIs) of dislocations. The approach utilizes both the Bloch wave formalism and the scattering matrix formalism to generate electron channeling patterns (ECPs). The latter formalism is then adapted to include the effect of lattice defects on the back-scattered electron yield, resulting in a computational algorithm for the simulation of ECCIs. Dislocations of known line direction and Burgers vector are imaged experimentally by ECCI and match well with simulated ECCIs for various channeling conditions. Experiment/simulation comparisons for ECPs and ECCIs are demonstrated for metals (Al), semiconductors (Si), and ceramics (SrTiO{sub 3}). - Highlights: • We provide a new formulation for electron channeling patterns formation. • We adapt the ECP model to include defect contrast, leading to a new ECCI algorithm. • We provide examples of excellent matches between experimental and simulated ECPs. • We illustrate the importance of surface relaxation for accurate ECCI simulations. • We obtain an excellent match of experimental and simulated dislocation images.

  2. High-resolution imaging by scanning electron microscopy of semithin sections in correlation with light microscopy.

    Science.gov (United States)

    Koga, Daisuke; Kusumi, Satoshi; Shodo, Ryusuke; Dan, Yukari; Ushiki, Tatsuo

    2015-12-01

    In this study, we introduce scanning electron microscopy (SEM) of semithin resin sections. In this technique, semithin sections were adhered on glass slides, stained with both uranyl acetate and lead citrate, and observed with a backscattered electron detector at a low accelerating voltage. As the specimens are stained in the same manner as conventional transmission electron microscopy (TEM), the contrast of SEM images of semithin sections was similar to TEM images of ultrathin sections. Using this technique, wide areas of semithin sections were also observed by SEM, without the obstruction of grids, which was inevitable for traditional TEM. This study also applied semithin section SEM to correlative light and electron microscopy. Correlative immunofluorescence microscopy and immune-SEM were performed in semithin sections of LR white resin-embedded specimens using a FluoroNanogold-labeled secondary antibody. Because LR white resin is hydrophilic and electron stable, this resin is suitable for immunostaining and SEM observation. Using correlative microscopy, the precise localization of the primary antibody was demonstrated by fluorescence microscopy and SEM. This method has great potential for studies examining the precise localization of molecules, including Golgi- and ER-associated proteins, in correlation with LM and SEM.

  3. Low energy electron imaging of domains and domain walls in magnesium-doped lithium niobate

    Science.gov (United States)

    Nataf, G. F.; Grysan, P.; Guennou, M.; Kreisel, J.; Martinotti, D.; Rountree, C. L.; Mathieu, C.; Barrett, N.

    2016-09-01

    The understanding of domain structures, specifically domain walls, currently attracts a significant attention in the field of (multi)-ferroic materials. In this article, we analyze contrast formation in full field electron microscopy applied to domains and domain walls in the uniaxial ferroelectric lithium niobate, which presents a large 3.8 eV band gap and for which conductive domain walls have been reported. We show that the transition from Mirror Electron Microscopy (MEM – electrons reflected) to Low Energy Electron Microscopy (LEEM – electrons backscattered) gives rise to a robust contrast between domains with upwards (Pup) and downwards (Pdown) polarization, and provides a measure of the difference in surface potential between the domains. We demonstrate that out-of-focus conditions of imaging produce contrast inversion, due to image distortion induced by charged surfaces, and also carry information on the polarization direction in the domains. Finally, we show that the intensity profile at domain walls provides experimental evidence for a local stray, lateral electric field.

  4. Low energy electron imaging of domains and domain walls in magnesium-doped lithium niobate

    Science.gov (United States)

    Nataf, G. F.; Grysan, P.; Guennou, M.; Kreisel, J.; Martinotti, D.; Rountree, C. L.; Mathieu, C.; Barrett, N.

    2016-01-01

    The understanding of domain structures, specifically domain walls, currently attracts a significant attention in the field of (multi)-ferroic materials. In this article, we analyze contrast formation in full field electron microscopy applied to domains and domain walls in the uniaxial ferroelectric lithium niobate, which presents a large 3.8 eV band gap and for which conductive domain walls have been reported. We show that the transition from Mirror Electron Microscopy (MEM – electrons reflected) to Low Energy Electron Microscopy (LEEM – electrons backscattered) gives rise to a robust contrast between domains with upwards (Pup) and downwards (Pdown) polarization, and provides a measure of the difference in surface potential between the domains. We demonstrate that out-of-focus conditions of imaging produce contrast inversion, due to image distortion induced by charged surfaces, and also carry information on the polarization direction in the domains. Finally, we show that the intensity profile at domain walls provides experimental evidence for a local stray, lateral electric field. PMID:27608605

  5. Low energy electron imaging of domains and domain walls in magnesium-doped lithium niobate.

    Science.gov (United States)

    Nataf, G F; Grysan, P; Guennou, M; Kreisel, J; Martinotti, D; Rountree, C L; Mathieu, C; Barrett, N

    2016-01-01

    The understanding of domain structures, specifically domain walls, currently attracts a significant attention in the field of (multi)-ferroic materials. In this article, we analyze contrast formation in full field electron microscopy applied to domains and domain walls in the uniaxial ferroelectric lithium niobate, which presents a large 3.8 eV band gap and for which conductive domain walls have been reported. We show that the transition from Mirror Electron Microscopy (MEM - electrons reflected) to Low Energy Electron Microscopy (LEEM - electrons backscattered) gives rise to a robust contrast between domains with upwards (Pup) and downwards (Pdown) polarization, and provides a measure of the difference in surface potential between the domains. We demonstrate that out-of-focus conditions of imaging produce contrast inversion, due to image distortion induced by charged surfaces, and also carry information on the polarization direction in the domains. Finally, we show that the intensity profile at domain walls provides experimental evidence for a local stray, lateral electric field. PMID:27608605

  6. Damage Assessment of Heat Resistant Steels through Electron BackScatter Diffraction Strain Analysis under Creep and Creep-Fatigue Conditions

    Science.gov (United States)

    Fujiyama, Kazunari; Kimachi, Hirohisa; Tsuboi, Toshiki; Hagiwara, Hiroyuki; Ogino, Shotaro; Mizutani, Yoshiki

    EBSD(Electron BackScatter Diffraction) analyses were conducted for studying the quantitative microstructural metrics of creep and creep-fatigue damage for austenitic SUS304HTB boiler tube steel and ferritic Mod.9Cr piping steel. KAM(Kernel Average Misorientation) maps and GOS(Grain Orientation Spread) maps were obtained for these samples and the area averaged values KAMave and GOSave were obtained. While the increasing trends of these misorientation metrics were observed for SUS304HTB steel, the decreasing trends were observed for damaged Mod.9Cr steel with extensive recovery of subgrain structure. To establish more universal parameter representing the accumulation of damage to compensate these opposite trends, the EBSD strain parameters were introduced for converting the misorientation changes into the quantities representing accumulated permanent strains during creep and creep-fatigue damage process. As KAM values were dependent on the pixel size (inversely proportional to the observation magnification) and the permanent strain could be expressed as the shear strain which was the product of dislocation density, Burgers vector and dislocation movement distance, two KAM strain parameters MεKAMnet and MεδKAMave were introduced as the sum of product of the noise subtracted KAMnet and the absolute change from initial value δKAMave with dislocation movement distance divided by pixel size. MεδKAMave parameter showed better relationship both with creep strain in creep tests and accumulated creep strain range in creep-fatigue tests. This parameter can be used as the strain-based damage evaluation and detector of final failure.

  7. Analysis of verification image using electronic portal imaging devices (EPID)

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Shinichi; Matsumoto, Mitsuhiro; Hasegawa, Hironori; Satoh, Kazuhiko; Sakurai, Kuniaki; Kawagoe, Yasumitsu; Kusumi, Yoshimi [Osaka Univ., Suita (Japan). Hospital

    1999-05-01

    We studied the evaluation of patient set-up error by verification image using electronic portal imaging devices (EPID). We analyzed which cleared 3 mm in our hospital for visual by using a distance measurement function. The body parts examined included the head and neck, thorax, pelvis and abdomen. The items that were evaluated included shell, Pb block, multi-leaf collimator and landmark. Patient set-up error was 10.4%, with that for the pelvis especially poor. The visual false rate was 17.9%. The result for the abdomen was poor because of the absence of landmark. We showed a decrease in patient set-up error by using EPID and improvement of radiotherapy. (author)

  8. Response in electrostatic analyzers due to backscattered electrons: case study analysis with the Juno Jovian Auroral Distribution Experiment-Electron instrument.

    Science.gov (United States)

    Clark, G; Allegrini, F; Randol, B M; McComas, D J; Louarn, P

    2013-10-01

    In this study, we introduce a model to characterize electron scattering in an electrostatic analyzer. We show that electrons between 0.5 and 30 keV scatter from internal surfaces to produce a response up to ~20% of the ideal, unscattered response. We compare our model results to laboratory data from the Jovian Auroral Distribution Experiment-Electron sensor onboard the NASA Juno mission. Our model reproduces the measured energy-angle response of the instrument well. Understanding and quantifying this scattering process is beneficial to the analysis of scientific data as well as future instrument optimization. PMID:24182165

  9. Correlative scanning electron and confocal microscopy imaging of labeled cells coated by indium-tin-oxide.

    Science.gov (United States)

    Rodighiero, Simona; Torre, Bruno; Sogne, Elisa; Ruffilli, Roberta; Cagnoli, Cinzia; Francolini, Maura; Di Fabrizio, Enzo; Falqui, Andrea

    2015-06-01

    Confocal microscopy imaging of cells allows to visualize the presence of specific antigens by using fluorescent tags or fluorescent proteins, with resolution of few hundreds of nanometers, providing their localization in a large field-of-view and the understanding of their cellular function. Conversely, in scanning electron microscopy (SEM), the surface morphology of cells is imaged down to nanometer scale using secondary electrons. Combining both imaging techniques have brought to the correlative light and electron microscopy, contributing to investigate the existing relationships between biological surface structures and functions. Furthermore, in SEM, backscattered electrons (BSE) can image local compositional differences, like those due to nanosized gold particles labeling cellular surface antigens. To perform SEM imaging of cells, they could be grown on conducting substrates, but obtaining images of limited quality. Alternatively, they could be rendered electrically conductive, coating them with a thin metal layer. However, when BSE are collected to detect gold-labeled surface antigens, heavy metals cannot be used as coating material, as they would mask the BSE signal produced by the markers. Cell surface could be then coated with a thin layer of chromium, but this results in a loss of conductivity due to the fast chromium oxidation, if the samples come in contact with air. In order to overcome these major limitations, a thin layer of indium-tin-oxide was deposited by ion-sputtering on gold-decorated HeLa cells and neurons. Indium-tin-oxide was able to provide stable electrical conductivity and preservation of the BSE signal coming from the gold-conjugated markers. PMID:25810353

  10. Correlative scanning electron and confocal microscopy imaging of labeled cells coated by indium-tin-oxide

    KAUST Repository

    Rodighiero, Simona

    2015-03-22

    Confocal microscopy imaging of cells allows to visualize the presence of specific antigens by using fluorescent tags or fluorescent proteins, with resolution of few hundreds of nanometers, providing their localization in a large field-of-view and the understanding of their cellular function. Conversely, in scanning electron microscopy (SEM), the surface morphology of cells is imaged down to nanometer scale using secondary electrons. Combining both imaging techniques have brought to the correlative light and electron microscopy, contributing to investigate the existing relationships between biological surface structures and functions. Furthermore, in SEM, backscattered electrons (BSE) can image local compositional differences, like those due to nanosized gold particles labeling cellular surface antigens. To perform SEM imaging of cells, they could be grown on conducting substrates, but obtaining images of limited quality. Alternatively, they could be rendered electrically conductive, coating them with a thin metal layer. However, when BSE are collected to detect gold-labeled surface antigens, heavy metals cannot be used as coating material, as they would mask the BSE signal produced by the markers. Cell surface could be then coated with a thin layer of chromium, but this results in a loss of conductivity due to the fast chromium oxidation, if the samples come in contact with air. In order to overcome these major limitations, a thin layer of indium-tin-oxide was deposited by ion-sputtering on gold-decorated HeLa cells and neurons. Indium-tin-oxide was able to provide stable electrical conductivity and preservation of the BSE signal coming from the gold-conjugated markers. © 2015 Wiley Periodicals, Inc.

  11. Backscattering of gyrotron radiation and short-wavelength turbulence during electron cyclotron resonance plasma heating in the L-2M stellarator

    Energy Technology Data Exchange (ETDEWEB)

    Batanov, G. M.; Borzosekov, V. D., E-mail: tinborz@gmail.com; Kovrizhnykh, L. M.; Kolik, L. V.; Konchekov, E. M.; Malakhov, D. V.; Petrov, A. E.; Sarksyan, K. A.; Skvortsova, N. N.; Stepakhin, V. D.; Kharchev, N. K. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation)

    2013-06-15

    Backscattering of gyrotron radiation ({theta} = {pi}) by short-wavelength density fluctuations (k{sub Up-Tack} = 30 cm{sup -1}) in the plasma of the L-2M stellarator was studied under conditions of electron cyclotron resonance (ECR) plasma heating at the second harmonic of the electron gyrofrequency (75 GHz). The scattering of the O-wave emerging due to the splitting of the linearly polarized gyrotron radiation into the X- and O-waves was analyzed. The signal obtained after homodyne detection of scattered radiation is a result of interference of the reference signal, the quasi-steady component, and the fast oscillating component. The coefficients of reflection of the quasi-steady component, R{sub =}{sup 2}(Y), and fast oscillating component, R{sub {approx}}{sup 2}(Y), of scattered radiation are estimated. The growth of the R{sub {approx}}{sup 2}(Y) coefficient from 3.7 Multiplication-Sign 10{sup -4} to 5.2 Multiplication-Sign 10{sup -4} with increasing ECR heating power from 190 to 430 kW is found to correlate with the decrease in the energy lifetime from 1.9 to 1.46 ms. The relative density of short-wavelength fluctuations is estimated to be Left-Pointing-Angle-Bracket n{sub {approx}}{sup 2} Right-Pointing-Angle-Bracket / Left-Pointing-Angle-Bracket n{sub e}{sup 2} Right-Pointing-Angle-Bracket = 3 Multiplication-Sign 10{sup -7}. It is shown that the frequencies of short-wavelength fluctuations are in the range 10-150 kHz. The recorded short-wavelength fluctuations can be interpreted as structural turbulence, the energy of which comprises {approx}10% of the total fluctuations energy. Simulations of transport processes show that neoclassical heat fluxes are much smaller than anomalous ones. It is suggested that short-wavelength turbulence plays a decisive role in the anomalous heat transport.

  12. 1 meter resolution GeoTIFF image of the sidescan sonar backscatter imagery of Boston Harbor and Approaches (BH_1MBS.TIF, UTM 19, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data are high-resolution acoustic backscatter measurements of the seafloor from Boston Harbor and the harbor approaches, Massachusetts. Approximately 170 km...

  13. NOAA TIFF Image - 50m Backscatter, Charleston Bump - Deep Coral Priority Areas - NOAA Ship Thomas Jefferson - (2007), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 30x30 meter cell size representing the backscatter intensity of the Charleston Bump off of the South Atlantic Bight,...

  14. NOAA TIFF Image - .75m Multibeam Backscatter, US Virgin Islands - Vieques Island (El Seco) - Project NF-09-01 - (2009), UTM 20N WGS 84 (NCEI Accession 0131857)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a GeoTIFF with .75x.75 meter cell size representing the backscatter or intensity of sound returned from the seafloor in "El Seco" east of...

  15. NOAA TIFF Image - .75m Multibeam Backscatter, US Virgin Islands - Vieques Island (El Seco) - Project NF-09-01 - (2009), UTM 20N WGS 84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a GeoTIFF with .75x.75 meter cell size representing the backscatter or intensity of sound returned from the seafloor in "El Seco" east of...

  16. NOAA TIFF Image - LIS_2014_Biogeo_Backscatter_1m.tif - Benthic Habitat Characterization - Biogeographic Branch - (2014), UTM 18N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified backscatter GeoTiff with 1x1 meter cell size representing the 2014 Long Island Sound Benthic Habitat Priority Area of Interest off...

  17. NOAA TIFF Image - 3x3m Multibeam Backscatter, US Virgin Islands - Vieques Island (South Bank) - Project NF-09-01 - (2009), UTM 20N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a GeoTIFF with 3x3 meter cell size representing the backscatter or intensity of sound returned from the seafloor on the bank/shelf escarpment...

  18. NOAA TIFF Image - 3m Backscatter Mosaic, Florida Deep Coral Areas (Miami) - Lost Coast Explorer - (2010), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 3x3 meter cell size representing the backscatter (intensity) of several deep coral priority areas off the Atlantic...

  19. NOAA TIFF Image - 10m Backscatter Mosaic, South Atlantic Bight - Deep Coral Priority Areas - NOAA Ship Nancy Foster - (2009), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 10x10 meter cell size representing the backscatter (intensity) of several deep coral priority areas off the South...

  20. NOAA TIFF Image - 5m Backscatter Mosaic, South Atlantic Bight - Deep Coral Priority Areas - NOAA Ship Nancy Foster - (2007), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 5x5 meter cell size representing the backscatter (intensity) of several deep coral priority areas off the South...

  1. NOAA TIFF Image - 30m Backscatter, Charleston Bump - Deep Coral Priority Areas - NOAA Ship Thomas Jefferson - (2007), UTM 17N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified GeoTiff with 30x30 meter cell size representing the backscatter intensity of the Charleston Bump off of the South Atlantic Bight,...

  2. The next generation of electron cyclotron emission imaging diagnostics (invited)

    NARCIS (Netherlands)

    Zhang, P.; Domier, C.W.; Liang, T.; Kong, X.; Tobias, B.; Shen, Z.; N C Luhmann Jr.,; Park, H.; Classen, I.G.J.; van de Pol, M.J.; Donne, A. J. H.; R. Jaspers,

    2008-01-01

    A 128 channel two-dimensional electron cyclotron emission imaging system collects time-resolved 16x8 images of T-e profiles and fluctuations on the TEXTOR tokamak. Electron cyclotron emission imaging (ECEI) is undergoing significant changes which promise to revolutionize and extend its capabilities

  3. The use of electron Rutherford backscattering to characterize novel electronic materials as illustrated by a case study of sputter-deposited NbO{sub x} films

    Energy Technology Data Exchange (ETDEWEB)

    Vos, M., E-mail: maarten.vos@anu.edu.au [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Liu, X. [Electronic Materials Engineering Department, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Grande, P.L. [Electronic Materials Engineering Department, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Nandi, S.K. [Electronic Materials Engineering Department, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Research School of Astronomy and Astrophysics, The Australian National University, Canberra, ACT 2611 (Australia); Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh); Venkatachalam, D.K.; Elliman, R.G. [Electronic Materials Engineering Department, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia)

    2014-12-01

    Electrons scattered over large angles at relatively high energies (40 keV) are used to study NbO{sub x} films. These films were deposited by reactive sputter deposition on a Si substrate using a Nb target and an Ar/O{sub 2} gas mixture. Energy spectra of electrons scattered from such samples exhibit elastic scattering peaks for each component due to the energy difference associated with scattering from different masses. The spectra provide in this way information about the film thickness as well as its stoichiometry. The stoichiometry and the deposition rate depends on the concentration of O{sub 2} in the mixture. For Nb{sub 2}O{sub 5}-like films the energy loss measurements also give an estimate of the band gap, but for Nb films with lower O concentration the band gap is not resolved. This work illustrates the possibility of characterizing modern transition metal oxide films in a fairly simple electron scattering experiment.

  4. Imaging Cytoskeleton Components by Electron Microscopy

    Science.gov (United States)

    Svitkina, Tatyana

    2016-01-01

    The cytoskeleton is a complex of detergent-insoluble components of the cytoplasm playing critical roles in cell motility, shape generation, and mechanical properties of a cell. Fibrillar polymers—actin filaments, microtubules, and intermediate filaments—are major constituents of the cytoskeleton, which constantly change their organization during cellular activities. The actin cytoskeleton is especially polymorphic, as actin filaments can form multiple higher order assemblies performing different functions. Structural information about cytoskeleton organization is critical for understanding its functions and mechanisms underlying various forms of cellular activity. Because of the nanometer-scale thickness of cytoskeletal fibers, electron microscopy (EM) is a key tool to determine the structure of the cytoskeleton. This article describes application of rotary shadowing (or metal replica) EM for visualization of the cytoskeleton. The procedure is applicable to thin cultured cells growing on glass coverslips and consists of detergent extraction of cells to expose their cytoskeleton, chemical fixation to provide stability, ethanol dehydration and critical point drying to preserve three-dimensionality, rotary shadowing with platinum to create contrast, and carbon coating to stabilize replicas. This technique provides easily interpretable three-dimensional images, in which individual cytoskeletal fibers are clearly resolved, and individual proteins can be identified by immunogold labeling. More importantly, replica EM is easily compatible with live cell imaging, so that one can correlate the dynamics of a cell or its components, e.g., expressed fluorescent proteins, with high resolution structural organization of the cytoskeleton in the same cell. PMID:26498781

  5. Electronic terahertz imaging for security applications

    Science.gov (United States)

    Trontelj, J.; Sešek, A.

    2016-02-01

    A sophisticated THz system with 3D imaging and narrow band spectroscopy capability is presented in the paper. The key system components are the THz source, THz detector/mixer array, scanning optics, and the signal processing unit. The system is all electronic and is portable. A battery operation option allows several hours of autonomy. The most important parameters of the THz source are output power, illumination beam size and directivity, frequency modulation range, and maximal modulation frequency. The low phase noise is also a very important parameter. Optimization of these parameters is discussed in the paper. The THz source is all solid state, composed of a phase-locked oscillator, an amplifier, and frequency multipliers. The most important element of the THz system is its sensor, which performs both signal detection and at the same time mixing of the LO signal and received signal from the target. The sensor is antenna coupled nanobolometer fabricated in a linear array of eight pixels. The sensors are suspended in the vacuum to achieve an excellent signal-to-noise ratio. The quadratic characteristic of the nano-bolometer extends over six decades allowing a large dynamic range and very high LO signal levels. The scanning mirror integrated into the system allows imaging of 1024 to 8162 pixels in the x and y dimensions that are expanded to the third dimension with a resolution of few micrometers.

  6. NOAA TIFF Image - 8m Backscatter Mosaic, Puerto Rico 2012-2013, Northeast Reserve, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-13-2 USVI (2013) and M-I907-NF-12 (2012), UTM 20N NAD83 (NCEI Accession 0131855)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents an 8 meter resolution backscatter mosaic of a reef shelf/bank and the steep slopes and canyons of the NE Reserve, offshore of Fajardo, Puerto...

  7. NOAA TIFF Image - 8m Backscatter Mosaic, Puerto Rico 2012-2013, Northeast Reserve, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-13-2 USVI (2013) and M-I907-NF-12 (2012), UTM 20N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents an 8 meter resolution backscatter mosaic of a reef shelf/bank and the steep slopes and canyons of the NE Reserve, offshore of Fajardo, Puerto...

  8. Thermal imaging diagnostics of high-current electron beams.

    Science.gov (United States)

    Pushkarev, A; Kholodnaya, G; Sazonov, R; Ponomarev, D

    2012-10-01

    The thermal imaging diagnostics of measuring pulsed electron beam energy density is presented. It provides control of the electron energy spectrum and a measure of the density distribution of the electron beam cross section, the spatial distribution of electrons with energies in the selected range, and the total energy of the electron beam. The diagnostics is based on the thermal imager registration of the imaging electron beam thermal print in a material with low bulk density and low thermal conductivity. Testing of the thermal imaging diagnostics has been conducted on a pulsed electron accelerator TEU-500. The energy of the electrons was 300-500 keV, the density of the electron current was 0.1-0.4 kA/cm(2), the duration of the pulse (at half-height) was 60 ns, and the energy in the pulse was up to 100 J. To register the thermal print, a thermal imager Fluke-Ti10 was used. Testing showed that the sensitivity of a typical thermal imager provides the registration of a pulsed electron beam heat pattern within one pulse with energy density over 0.1 J/cm(2) (or with current density over 10 A/cm(2), pulse duration of 60 ns and electron energy of 400 keV) with the spatial resolution of 0.9-1 mm. In contrast to the method of using radiosensitive (dosimetric) materials, thermal imaging diagnostics does not require either expensive consumables, or plenty of processing time. PMID:23126757

  9. Transmission electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1989-01-01

    The aim of this book is to present the theory of image and contrast formation and the analytical modes in transmission electron microscopy The principles of particle and wave optics of electrons are described Electron-specimen interactions are discussed for evaluating the theory of scattering and phase contrast Also discussed are the kinematical and dynamical theories of electron diffraction and their applications for crystal structure determination and imaging of lattice defects X-ray microanalysis and energy-loss spectroscopy are treated as analytical methods The second edition includes discussion of recent progress, especially in the areas of energy-loss spectroscopy, crystal-lattice imaging and reflection electron microscopy

  10. Electronic imaging and high spatial resolution slow electron spectroscopy

    International Nuclear Information System (INIS)

    Scanning electron microscopy and scanning Auger are now commonly used techniques. They are extended here to the complete electron energy distribution. It is shown that pictures can be obtained with electron energy loss peaks or with true secondary electron peaks of very low energy. These pictures are performed with very low primary electron energies (Esub(p) approximately 250 eV) and a fairly good spatial resolution. A very wide field of application of these techniques is now open. In the next future, work function and adsorbed hydrogen micromapping will be obtained

  11. Transmission electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1993-01-01

    "Transmission Electron Microscopy" presents the theory of image and contrastformation, and the analytical modes in transmission electron microscopy Theprinciples of particle and wave optics of electrons are described Electron-specimen interactions are discussed for evaluating the theory of scattering and phase contrast Also analysed are the kinetical and dynamical theories of electron diffraction and their applications for crystal-structure determination and imaging of lattices and their defects X-ray microanalysis and electron energy-loss spectroscopy are treated as analytical methods The third edition includes a brief discussionof Schottky emission guns, some clarification of minor details, and references to the recent literature

  12. Characteristics of different frequency ranges in scanning electron microscope images

    Energy Technology Data Exchange (ETDEWEB)

    Sim, K. S., E-mail: kssim@mmu.edu.my; Nia, M. E.; Tan, T. L.; Tso, C. P.; Ee, C. S. [Faculty of Engineering and Technology, Multimedia University, 75450 Melaka (Malaysia)

    2015-07-22

    We demonstrate a new approach to characterize the frequency range in general scanning electron microscope (SEM) images. First, pure frequency images are generated from low frequency to high frequency, and then, the magnification of each type of frequency image is implemented. By comparing the edge percentage of the SEM image to the self-generated frequency images, we can define the frequency ranges of the SEM images. Characterization of frequency ranges of SEM images benefits further processing and analysis of those SEM images, such as in noise filtering and contrast enhancement.

  13. Sub-MeV tunably polarized X-ray production with laser Thomson backscattering

    Science.gov (United States)

    Kawase, K.; Kando, M.; Hayakawa, T.; Daito, I.; Kondo, S.; Homma, T.; Kameshima, T.; Kotaki, H.; Chen, L.-M.; Fukuda, Y.; Faenov, A.; Shizuma, T.; Fujiwara, M.; Bulanov, S. V.; Kimura, T.; Tajima, T.

    2008-05-01

    Reported in this article is the generation of unique polarized x-rays in the sub-MeV region by means of the Thomson backscattering of the Nd:YAG laser photon with a wavelength of 1064nm on the 150MeV electron from the microtron accelerator. The maximum energy of the x-ray photons is estimated to be about 400keV. The total energy of the backscattered x-ray pulse is measured with an imaging plate and a LYSO scintillator. The angular divergence of the x-rays is also measured by using the imaging plate. We confirm that the x-ray beam is polarized according to the laser polarization direction with the Compton scattering method. In addition, we demonstrate the imaging of the object shielded by lead with the generated x-rays.

  14. Compact low-cost detection electronics for optical coherence imaging

    OpenAIRE

    Akcay, A. C.; Lee, K. S.; Furenlid, L.R.; Costa, M A; Rolland, J.P.

    2006-01-01

    A compact and low-cost detection electronics scheme for optical coherence imaging is demonstrated. The performance of the designed electronics is analyzed in comparison to a commercial lock-in amplifier of equal bandwidth. Images of a fresh-onion sample are presented for each detection configuration.

  15. Electromagnetic backscattering from one-dimensional drifting fractal sea surface II:Electromagnetic backscattering model

    Institute of Scientific and Technical Information of China (English)

    谢涛; William Perrie; 赵尚卓; 方贺; 于文金; 何宜军

    2016-01-01

    Sea surface current has a significant influence on electromagnetic (EM) backscattering signals and may constitute a dominant synthetic aperture radar (SAR) imaging mechanism. An effective EM backscattering model for a one-dimensional drifting fractal sea surface is presented in this paper. This model is used to simulate EM backscattering signals from the drifting sea surface. Numerical results show that ocean currents have a significant influence on EM backscattering signals from the sea surface. The normalized radar cross section (NRCS) discrepancies between the model for a coupled wave-current fractal sea surface and the model for an uncoupled fractal sea surface increase with the increase of incidence angle, as well as with increasing ocean currents. Ocean currents that are parallel to the direction of the wave can weaken the EM backscattering signal intensity, while the EM backscattering signal is intensified by ocean currents propagating oppositely to the wave direction. The model presented in this paper can be used to study the SAR imaging mechanism for a drifting sea surface.

  16. Electromagnetic backscattering from one-dimensional drifting fractal sea surface II: Electromagnetic backscattering model

    Science.gov (United States)

    Tao, Xie; William, Perrie; Shang-Zhuo, Zhao; He, Fang; Wen-Jin, Yu; Yi-Jun, He

    2016-07-01

    Sea surface current has a significant influence on electromagnetic (EM) backscattering signals and may constitute a dominant synthetic aperture radar (SAR) imaging mechanism. An effective EM backscattering model for a one-dimensional drifting fractal sea surface is presented in this paper. This model is used to simulate EM backscattering signals from the drifting sea surface. Numerical results show that ocean currents have a significant influence on EM backscattering signals from the sea surface. The normalized radar cross section (NRCS) discrepancies between the model for a coupled wave-current fractal sea surface and the model for an uncoupled fractal sea surface increase with the increase of incidence angle, as well as with increasing ocean currents. Ocean currents that are parallel to the direction of the wave can weaken the EM backscattering signal intensity, while the EM backscattering signal is intensified by ocean currents propagating oppositely to the wave direction. The model presented in this paper can be used to study the SAR imaging mechanism for a drifting sea surface. Project supported by the National Natural Science Foundation of China (Grant No. 41276187), the Global Change Research Program of China (Grant No. 2015CB953901), the Priority Academic Program Development of Jiangsu Higher Education Institutions, China, the Program for the Innovation Research and Entrepreneurship Team in Jiangsu Province, China, the Canadian Program on Energy Research and Development, and the Canadian World Class Tanker Safety Service Program.

  17. Transmission electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1997-01-01

    Transmission Electron Microscopy presents the theory of image and contrast formation, and the analytical modes in transmission electron microscopy. The principles of particle and wave optics of electrons are described. Electron-specimen interactions are discussed for evaluating the theory of scattering and phase contrast. Also discussed are the kinematical and dynamical theories of electron diffraction and their applications for crystal-structure analysis and imaging of lattices and their defects. X-ray micronanalysis and electron energy-loss spectroscopy are treated as analytical methods. Specimen damage and contamination by electron irradiation limits the resolution for biological and some inorganic specimens. This fourth edition includes discussion of recent progress, especially in the area of Schottky emission guns, convergent-beam electron diffraction, electron tomography, holography and the high resolution of crystal lattices.

  18. CHANGES OF BACKSCATTERING PARAMETERS DURING CHILLING INJURY IN BANANAS

    Directory of Open Access Journals (Sweden)

    NORHASHILA HASHIM

    2014-06-01

    Full Text Available The change in backscattering parameters during the appearance of chilling injury in bananas was investigated. Bananas were stored at a chilling temperature for two days and the degrees of the chilling injuries that appeared were measured before, during and after storage using backscattering imaging and visual assessment. Laser lights at 660 nm and 785 nm wavelengths were shot consecutively onto the samples in a dark room and a camera was used to capture the backscattered lights that appeared on the samples. The captured images were analysed and the changes of intensity against pixel count were plotted into graphs. The plotted graph provides useful information of backscattering parameters such as inflection point (IP, slope after inflection point (SA, and full width at half maximum (FWHM and saturation radius (RSAT. Results of statistical analysis indicated that there were significant changes of these backscattering parameters as chilling injury developed.

  19. Foucault imaging by using non-dedicated transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, Yoshifumi [Science and Medical Systems Business Group, Hitachi High-Technologies Corp., Ichige, Hitachinaka, Ibaraki 312-8504 (Japan); Matsumoto, Hiroaki [Corporate Manufacturing Strategy Group, Hitachi High-Technologies Corp., Ishikawa-cho, Hitachinaka, Ibaraki 312-1991 (Japan); Harada, Ken [Central Research Laboratory, Hitachi Ltd., Hatoyama, Saitama 350-0395 (Japan)

    2012-08-27

    An electron optical system for observing Foucault images was constructed using a conventional transmission electron microscope without any special equipment for Lorentz microscopy. The objective lens was switched off and an electron beam was converged by a condenser optical system to the crossover on the selected area aperture plane. The selected area aperture was used as an objective aperture to select the deflected beam for Foucault mode, and the successive image-forming lenses were controlled for observation of the specimen images. The irradiation area on the specimen was controlled by selecting the appropriate diameter of the condenser aperture.

  20. Foucault imaging by using non-dedicated transmission electron microscope

    Science.gov (United States)

    Taniguchi, Yoshifumi; Matsumoto, Hiroaki; Harada, Ken

    2012-08-01

    An electron optical system for observing Foucault images was constructed using a conventional transmission electron microscope without any special equipment for Lorentz microscopy. The objective lens was switched off and an electron beam was converged by a condenser optical system to the crossover on the selected area aperture plane. The selected area aperture was used as an objective aperture to select the deflected beam for Foucault mode, and the successive image-forming lenses were controlled for observation of the specimen images. The irradiation area on the specimen was controlled by selecting the appropriate diameter of the condenser aperture.

  1. Foucault imaging by using non-dedicated transmission electron microscope

    International Nuclear Information System (INIS)

    An electron optical system for observing Foucault images was constructed using a conventional transmission electron microscope without any special equipment for Lorentz microscopy. The objective lens was switched off and an electron beam was converged by a condenser optical system to the crossover on the selected area aperture plane. The selected area aperture was used as an objective aperture to select the deflected beam for Foucault mode, and the successive image-forming lenses were controlled for observation of the specimen images. The irradiation area on the specimen was controlled by selecting the appropriate diameter of the condenser aperture.

  2. Automated Classification Of Scanning Electron Microscope Particle Images Using Morphological Analysis

    Science.gov (United States)

    Lamarche, B. L.; Lewis, R. R.; Girvin, D. C.; McKinley, J. P.

    2008-12-01

    We are developing a software tool that can automatically classify anthropogenic and natural aerosol particulates using morphological analysis. Our method was developed using SEM (background and secondary electron) images of single particles. Particle silhouettes are detected and converted into polygons using Intel's OpenCV image processing library. Our analysis then proceeds independently for the two kinds of images. Analysis of secondary images concerns itself solely with the silhouette and seeks to quantify its shape and roughness. Traversing the polygon with spline interpolation, we uniformly sample k(s), the signed curvature of the silhouette's path as a function of distance along the perimeter s. k(s) is invariant under rotation and translation. The power spectrum of k(s) qualitatively shows both shape and roughness: more power at low frequencies indicates variation in shape; more power at higher frequencies indicates a rougher silhouette. We present a series of filters (low-, band-, and high-pass) which we convolve with k(s) to yield a set of parameters that characterize the shape and roughness numerically. Analysis of backscatter images focuses on the (visual) texture, which is the result of both composition and geometry. Using the silhouette as a boundary, we compute the variogram, a statistical measure of inter-pixel covariance as a function of distance. Variograms take on characteristic curves, which we fit with a heuristic, asymptotic function that uses a small set of parameters. The combination of silhouette and variogram fit parameters forms the basis of a multidimensional classification space whose dimensionality we may reduce by principal component analysis and whose region boundaries allow us to classify new particles. This analysis is performed without a priori knowledge of other physical, chemical, or climatic properties. The method will be adapted to multi-particulate images.

  3. Imaging electron detectors for low-voltage TEM

    Energy Technology Data Exchange (ETDEWEB)

    Moldovan, G; Kirkland, A I, E-mail: grigore.moldovan@materials.ox.ac.u [Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH (United Kingdom)

    2010-07-01

    There is an increasing effort for the development of transmission electron microscopes operating at accelerating voltages of less that 100 kV, down to 20 kV. This work aims to clarify if the technology of conventional indirect scintillator-CCD cameras is suitable to record images formed with electrons of such low energy and how its performance compare to that of novel direct silicon imaging detectors. The performance of these imaging detectors is discussed in terms of modulation transfer function and detective quantum efficiency. It is demonstrated that whilst the performance of conventional scintillator-CCDs improves as the electron energy is dropped, it then peaks at 70 keV and then drops again. Optimum imaging performance at even lower energies is expected for the novel directly exposed detectors, which are capable of near 100% detective quantum efficiency at very low electron energies.

  4. Electronic aperture control devised for solid state imaging system

    Science.gov (United States)

    Anders, R. A.; Callahan, D. E.; Mc Cann, D. H.

    1968-01-01

    Electronic means of performing the equivalent of automatic aperture control has been devised for the new class of television cameras that incorporates a solid state imaging device in the form of phototransistor mosaic sensors.

  5. Imaging population transfer in atoms with ultrafast electron pulses

    Science.gov (United States)

    Shao, Hua-Chieh; Starace, Anthony F.

    2016-05-01

    Ultrafast electron diffraction and microscopy have made significant progress recently in investigating atomic-scale structural dynamics in gas-phase and condensed materials. With these advances, direct imaging of electronic motions in atoms and molecules by ultrafast electron diffraction is anticipated. We propose imaging a laser-driven coherent population transfer in lithium atoms by femtosecond ultrafast electron pulses. Valuable information and insight can be obtained from studying such a system in order to refine ultrafast electron techniques and to interpret experimental results. Adiabatic passage by level crossing is used to transfer the electron population from the 2 s to the 2 p state. Our simulations demonstrate the ability of ultrafast electron diffraction to image this population transfer, as the time-dependent diffraction images reflect the electronic motion in the scattering intensity and angular distribution. Furthermore, asymmetric diffraction patterns indicate that even the relative phases of the electronic wave function can be resolved, provided there is sufficient temporal resolution. This work has been supported in part by DOE Award No. DE-SC0012193 [H.-C.S.] and by NSF Grant No. PHYS-1505492 [A.F.S.].

  6. A new clustering algorithm for scanning electron microscope images

    Science.gov (United States)

    Yousef, Amr; Duraisamy, Prakash; Karim, Mohammad

    2016-04-01

    A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning it with a focused beam of electrons. The electrons interact with the sample atoms, producing various signals that are collected by detectors. The gathered signals contain information about the sample's surface topography and composition. The electron beam is generally scanned in a raster scan pattern, and the beam's position is combined with the detected signal to produce an image. The most common configuration for an SEM produces a single value per pixel, with the results usually rendered as grayscale images. The captured images may be produced with insufficient brightness, anomalous contrast, jagged edges, and poor quality due to low signal-to-noise ratio, grained topography and poor surface details. The segmentation of the SEM images is a tackling problems in the presence of the previously mentioned distortions. In this paper, we are stressing on the clustering of these type of images. In that sense, we evaluate the performance of the well-known unsupervised clustering and classification techniques such as connectivity based clustering (hierarchical clustering), centroid-based clustering, distribution-based clustering and density-based clustering. Furthermore, we propose a new spatial fuzzy clustering technique that works efficiently on this type of images and compare its results against these regular techniques in terms of clustering validation metrics.

  7. Dosimetry with a fluoroscopic electronic portal imaging device

    NARCIS (Netherlands)

    K.L. Pasma

    1999-01-01

    textabstractechniques for dosimetric verification of radiotherapy treatments using a CCD camera based fluoroscopic electronic portal imaging device (EPID) are described. The dosimetric characteristics of the EPID were investigated and a method was developed to derive portal dose images (PDIs) from m

  8. Thermal analysis of the ultraviolet imager camera and electronics

    Science.gov (United States)

    Dirks, Gregory J.

    1991-01-01

    The Ultraviolet Imaging experiment has undergone design changes that necessiate updating the reduced thermal models (RTM's) for both the Camera and Electronics. In addition, there are several mission scenarios that need to be evaluated in terms of thermal response of the instruments. The impact of these design changes and mission scenarios on the thermal performance of the Camera and Electronics assemblies is discussed.

  9. Analysis of electron energy-loss spectra and images

    NARCIS (Netherlands)

    C.W.J. Sorber (Lianne)

    1993-01-01

    textabstractSeveral methods are proposed for the elemental analysis of biological material with the use of electron energy-loss spectroscopy (EELS) and electron spectroscopic imaging (ESI) in a Zeiss EM902. For spectra, the Simplex-method was tested and compared to Egerton's 2- area method, the Stee

  10. CMOS Image Sensors: Electronic Camera On A Chip

    Science.gov (United States)

    Fossum, E. R.

    1995-01-01

    Recent advancements in CMOS image sensor technology are reviewed, including both passive pixel sensors and active pixel sensors. On- chip analog to digital converters and on-chip timing and control circuits permit realization of an electronic camera-on-a-chip. Highly miniaturized imaging systems based on CMOS image sensor technology are emerging as a competitor to charge-coupled devices for low cost uses.

  11. Scanning transmission electron microscopy imaging and analysis

    CERN Document Server

    Pennycook, Stephen J

    2011-01-01

    Provides the first comprehensive treatment of the physics and applications of this mainstream technique for imaging and analysis at the atomic level Presents applications of STEM in condensed matter physics, materials science, catalysis, and nanoscience Suitable for graduate students learning microscopy, researchers wishing to utilize STEM, as well as for specialists in other areas of microscopy Edited and written by leading researchers and practitioners

  12. Imaging and Measuring Electron Beam Dose Distributions Using Holographic Interferometry

    DEFF Research Database (Denmark)

    Miller, Arne; McLaughlin, W. L.

    1975-01-01

    Holographic interferometry was used to image and measure ionizing radiation depth-dose and isodose distributions in transparent liquids. Both broad and narrowly collimated electron beams from accelerators (2–10 MeV) provided short irradiation times of 30 ns to 0.6 s. Holographic images and measur......Holographic interferometry was used to image and measure ionizing radiation depth-dose and isodose distributions in transparent liquids. Both broad and narrowly collimated electron beams from accelerators (2–10 MeV) provided short irradiation times of 30 ns to 0.6 s. Holographic images...... and measurements of absorbed dose distributions were achieved in liquids of various densities and thermal properties and in water layers thinner than the electron range and with backings of materials of various densities and atomic numbers. The lowest detectable dose in some liquids was of the order of a few k...

  13. Scanning electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1985-01-01

    The aim of this book is to outline the physics of image formation, electron­ specimen interactions, imaging modes, the interpretation of micrographs and the use of quantitative modes "in scanning electron microscopy (SEM). lt forms a counterpart to Transmission Electron Microscopy (Vol. 36 of this Springer Series in Optical Sciences) . The book evolved from lectures delivered at the University of Münster and from a German text entitled Raster-Elektronenmikroskopie (Springer-Verlag), published in collaboration with my colleague Gerhard Pfefferkorn. In the introductory chapter, the principles of the SEM and of electron­ specimen interactions are described, the most important imaging modes and their associated contrast are summarized, and general aspects of eiemental analysis by x-ray and Auger electron emission are discussed. The electron gun and electron optics are discussed in Chap. 2 in order to show how an electron probe of small diameter can be formed, how the elec­ tron beam can be blanked at high fre...

  14. Quantitative methods for the analysis of electron microscope images

    DEFF Research Database (Denmark)

    Skands, Peter Ulrik Vallø

    1996-01-01

    The topic of this thesis is an general introduction to quantitative methods for the analysis of digital microscope images. The images presented are primarily been acquired from Scanning Electron Microscopes (SEM) and interfermeter microscopes (IFM). The topic is approached though several examples...... foundation of the thesis fall in the areas of: 1) Mathematical Morphology; 2) Distance transforms and applications; and 3) Fractal geometry. Image analysis opens in general the possibility of a quantitative and statistical well founded measurement of digital microscope images. Herein lies also the conditions...

  15. Survey of standards for electronic image displays

    Science.gov (United States)

    Rowe, William A.

    1996-01-01

    Electronic visual displays have been evolving from the 1960s basis of cathode ray tube (CRT) technology. Now, many other technologies are also available, including both flat panels and projection displays. Standards for these displays are being developed at both the national level and the international levels. Standards activity within the United States is in its infancy and is fragmented according to the inclination of each of the standards developing organizations. The latest round of flat panel display technology was primarily developed in Japan. Initially standards arose from component vendor-to-OEM customer relationships. As a result, Japanese standards for components are the best developed. The Electronics Industries Association of Japan (EIAJ) is providing their standards to the International Electrotechnical Commission (IEC) for adoption. On the international level, professional societies such as the human factors society (hfs) and the International Organization for Standardization (ISO) have completed major standards. Human factors society developed the first ergonomic standard hfs-100 and the ISO has developed some sections of a broader ergonomic standard ISO 9241. This paper addresses the organization of standards activity. Active organizations and their areas of focus are identified. The major standards that have been completed or are in development are described. Finally, suggestions for improving this standards activity are proposed.

  16. Detection of buried landmine with X-ray backscatter technique

    Science.gov (United States)

    Yuk, Sunwoo; Kim, Kwang Hyun; Yi, Yun

    2006-11-01

    We describe a continuously operating scanning X-ray imaging system developed for landmine detection based on a backscatter X-ray principle, thus detection is done from the same side as the source. The source operates at 120 kV p and 3 mA. To study the physics of Compton X-ray backscattering, the photon transport factor, backscatter factor (BSF) and backscatter probability (BSP) were simulated using Monte-Carlo calculations using the generalized particle transport program MCNP. Based on the Monte-Carlo analyses results, a mine detecting system has been designed. It potentially has a low false alarm rate and a high detection probability, and a direct imaging facility.

  17. Detection of buried landmine with X-ray backscatter technique

    Energy Technology Data Exchange (ETDEWEB)

    Yuk, Sunwoo [Department of Electronics and Information Engineering, Korea University, Seoul (Korea, Republic of)]. E-mail: sunwoo@korea.ac.kr; Kim, Kwang Hyun [Chosun University, 375, Seosuk-Dong, Dong-Gu, Gwangju (Korea, Republic of); Yi, Yun [Department of Electronics and Information Engineering, Korea University, Seoul (Korea, Republic of)

    2006-11-30

    We describe a continuously operating scanning X-ray imaging system developed for landmine detection based on a backscatter X-ray principle, thus detection is done from the same side as the source. The source operates at 120 kV p and 3 mA. To study the physics of Compton X-ray backscattering, the photon transport factor, backscatter factor (BSF) and backscatter probability (BSP) were simulated using Monte-Carlo calculations using the generalized particle transport program MCNP. Based on the Monte-Carlo analyses results, a mine detecting system has been designed. It potentially has a low false alarm rate and a high detection probability, and a direct imaging facility.

  18. TU-A-9A-03: Development and Verification of a Forward Model That Assists in Iterative Post-Processing Algorithms Used to Reduce Blur in Compton Backscatter Imaging Systems

    Energy Technology Data Exchange (ETDEWEB)

    Juneja, B; Gilland, D; Hintenlang, D; Doxsee, K; Bova, F [University Florida, Gainesville, FL (United States)

    2014-06-15

    Purpose: In Compton Backscatter Imaging (CBI), the source and detector reside on the same side of the patient. We previously demonstrated the applicability of CBI systems for medical purposes using an industrial system. To assist in post-processing images from a CBI system, a forward model based on radiation absorption and scatter principles has been developed. Methods: The forward model was developed in C++ using raytracing to track particles. The algorithm accepts phantoms of any size and resolution to calculate the fraction of incident photons scattered back to the detector, and can perform these calculations for any detector geometry and source specification. To validate the model, results were compared to MCNP-X, which is a Monte Carlo based simulation software, for various combinations of source specifications, detector geometries, and phantom compositions. Results: The model verified that the backscatter signal to the detector was based on three interaction probabilities: a) attenuation of photons going into the phantom, b) Compton scatter of photons toward the detector, and c) attenuation of photons coming out of the phantom. The results from the MCNP-X simulations and the forward model varied from 1 to 5%. This difference was less than 1% for energies higher than 30 keV, but was up to 4% for lower energies. At 50 keV, the difference was less than 1% for multiple detector widths and for both homogeneous and heterogeneous phantoms. Conclusion: As part of the optimization of a medical CBI system, an efficient and accurate forward model was constructed in C++ to estimate the output of CBI system. The model characterized individual components contributing to CBI output and increased computational efficiency over Monte Carlo simulations. It is now used in the development of novel post-processing algorithms that reduce image blur by reversing undesired contribution from outside the region of interest.

  19. TU-A-9A-03: Development and Verification of a Forward Model That Assists in Iterative Post-Processing Algorithms Used to Reduce Blur in Compton Backscatter Imaging Systems

    International Nuclear Information System (INIS)

    Purpose: In Compton Backscatter Imaging (CBI), the source and detector reside on the same side of the patient. We previously demonstrated the applicability of CBI systems for medical purposes using an industrial system. To assist in post-processing images from a CBI system, a forward model based on radiation absorption and scatter principles has been developed. Methods: The forward model was developed in C++ using raytracing to track particles. The algorithm accepts phantoms of any size and resolution to calculate the fraction of incident photons scattered back to the detector, and can perform these calculations for any detector geometry and source specification. To validate the model, results were compared to MCNP-X, which is a Monte Carlo based simulation software, for various combinations of source specifications, detector geometries, and phantom compositions. Results: The model verified that the backscatter signal to the detector was based on three interaction probabilities: a) attenuation of photons going into the phantom, b) Compton scatter of photons toward the detector, and c) attenuation of photons coming out of the phantom. The results from the MCNP-X simulations and the forward model varied from 1 to 5%. This difference was less than 1% for energies higher than 30 keV, but was up to 4% for lower energies. At 50 keV, the difference was less than 1% for multiple detector widths and for both homogeneous and heterogeneous phantoms. Conclusion: As part of the optimization of a medical CBI system, an efficient and accurate forward model was constructed in C++ to estimate the output of CBI system. The model characterized individual components contributing to CBI output and increased computational efficiency over Monte Carlo simulations. It is now used in the development of novel post-processing algorithms that reduce image blur by reversing undesired contribution from outside the region of interest

  20. Electron Spin Resonance Imaging Utilizing Localized Microwave Magnetic Field

    Science.gov (United States)

    Furusawa, Masahiro; Ikeya, Motoji

    1990-02-01

    A method for two-dimensional electron spin resonance (ESR) imaging utilizing a localized microwave field is presented with an application of the image processing technique. Microwaves are localized at the surface of a sample by placing a sample in contact with a pinholed cavity wall. A two-dimensional ESR image can be obtained by scanning the sample in contact with the cavity. Some ESR images which correspond to distribution of natural radiation damages and paramagnetic impurities in carbonate fossils of a crinoid and an ammonite are presented as applications in earth science. Resolution of a raw ESR image is restricted by the diameter of the hole (1 mm). Higher resolution of 0.2 mm is obtained by using a deconvolution algorithm and instrument function for the hole. Restored images of a test sample of DPPH and of a fossil crinoid are presented.

  1. Imaging hydrated microbial extracellular polymers: Comparative analysis by electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dohnalkova, A.C.; Marshall, M. J.; Arey, B. W.; Williams, K. H.; Buck, E. C.; Fredrickson, J. K.

    2011-01-01

    Microbe-mineral and -metal interactions represent a major intersection between the biosphere and geosphere but require high-resolution imaging and analytical tools for investigating microscale associations. Electron microscopy has been used extensively for geomicrobial investigations and although used bona fide, the traditional methods of sample preparation do not preserve the native morphology of microbiological components, especially extracellular polymers. Herein, we present a direct comparative analysis of microbial interactions using conventional electron microscopy approaches of imaging at room temperature and a suite of cryogenic electron microscopy methods providing imaging in the close-to-natural hydrated state. In situ, we observed an irreversible transformation of the hydrated bacterial extracellular polymers during the traditional dehydration-based sample preparation that resulted in their collapse into filamentous structures. Dehydration-induced polymer collapse can lead to inaccurate spatial relationships and hence could subsequently affect conclusions regarding nature of interactions between microbial extracellular polymers and their environment.

  2. Importance of daily electronic portal imaging in radiotherapy

    International Nuclear Information System (INIS)

    Full text: An audit was conducted on 20 randomly selected patients who had daily electronic portal imaging during the course of their radiotherapy treatment. The daily images were reviewed to determine whether they were within tolerance according to departmental protocol. If they were not, the actions that were taken were documented. Four treatment areas (spine, chest, breast and prostate) were compared among five patients belonging to each of these categories. The patients were also categorized according to their treatment intent (radical or palliative). A total of 889 electronic portal images of 475 fractions were audited and 33.5% of all fractions were outside tolerance. It was found that 95% of patients needed an action during their treatment and 80% of the patients needed a treatment centre move during the course of their treatment. We found that errors occurred throughout the treatment and it was not possible to predict patients who could have daily imaging omitted. Concordance between radiation therapists and radiation oncologists for identification of error was also investigated. Despite the use of familiar electronic portal imaging protocols, image reviewers (radiation therapists and radiation oncologists) disagreed in interpretation 10% of the time. Our results support the hypothesis that daily imaging may be a useful tool for patients undergoing radiotherapy and that imaging may be ideally carried out before each fraction. Image assessments would be ideally carried out by a team approach, with all images reviewed by both radiation therapists and radiation oncologists. This approach has significant resource implications and may require review of current Medicare and Health Program Grant reimbursements.

  3. The application of similar image retrieval in electronic commerce.

    Science.gov (United States)

    Hu, YuPing; Yin, Hua; Han, Dezhi; Yu, Fei

    2014-01-01

    Traditional online shopping platform (OSP), which searches product information by keywords, faces three problems: indirect search mode, large search space, and inaccuracy in search results. For solving these problems, we discuss and research the application of similar image retrieval in electronic commerce. Aiming at improving the network customers' experience and providing merchants with the accuracy of advertising, we design a reasonable and extensive electronic commerce application system, which includes three subsystems: image search display subsystem, image search subsystem, and product information collecting subsystem. This system can provide seamless connection between information platform and OSP, on which consumers can automatically and directly search similar images according to the pictures from information platform. At the same time, it can be used to provide accuracy of internet marketing for enterprises. The experiment shows the efficiency of constructing the system. PMID:24883411

  4. The application of similar image retrieval in electronic commerce.

    Science.gov (United States)

    Hu, YuPing; Yin, Hua; Han, Dezhi; Yu, Fei

    2014-01-01

    Traditional online shopping platform (OSP), which searches product information by keywords, faces three problems: indirect search mode, large search space, and inaccuracy in search results. For solving these problems, we discuss and research the application of similar image retrieval in electronic commerce. Aiming at improving the network customers' experience and providing merchants with the accuracy of advertising, we design a reasonable and extensive electronic commerce application system, which includes three subsystems: image search display subsystem, image search subsystem, and product information collecting subsystem. This system can provide seamless connection between information platform and OSP, on which consumers can automatically and directly search similar images according to the pictures from information platform. At the same time, it can be used to provide accuracy of internet marketing for enterprises. The experiment shows the efficiency of constructing the system.

  5. The Application of Similar Image Retrieval in Electronic Commerce

    Directory of Open Access Journals (Sweden)

    YuPing Hu

    2014-01-01

    Full Text Available Traditional online shopping platform (OSP, which searches product information by keywords, faces three problems: indirect search mode, large search space, and inaccuracy in search results. For solving these problems, we discuss and research the application of similar image retrieval in electronic commerce. Aiming at improving the network customers’ experience and providing merchants with the accuracy of advertising, we design a reasonable and extensive electronic commerce application system, which includes three subsystems: image search display subsystem, image search subsystem, and product information collecting subsystem. This system can provide seamless connection between information platform and OSP, on which consumers can automatically and directly search similar images according to the pictures from information platform. At the same time, it can be used to provide accuracy of internet marketing for enterprises. The experiment shows the efficiency of constructing the system.

  6. Note: An improved 3D imaging system for electron-electron coincidence measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Yun Fei; Lee, Suk Kyoung; Adhikari, Pradip; Herath, Thushani; Lingenfelter, Steven; Winney, Alexander H.; Li, Wen, E-mail: wli@chem.wayne.edu [Department of Chemistry, Wayne State University, Detroit, Michigan 48202 (United States)

    2015-09-15

    We demonstrate an improved imaging system that can achieve highly efficient 3D detection of two electrons in coincidence. The imaging system is based on a fast frame complementary metal-oxide semiconductor camera and a high-speed waveform digitizer. We have shown previously that this detection system is capable of 3D detection of ions and electrons with good temporal and spatial resolution. Here, we show that with a new timing analysis algorithm, this system can achieve an unprecedented dead-time (<0.7 ns) and dead-space (<1 mm) when detecting two electrons. A true zero dead-time detection is also demonstrated.

  7. Monte Carlo simulation of secondary electron images for real sample structures in scanning electron microscopy.

    Science.gov (United States)

    Zhang, P; Wang, H Y; Li, Y G; Mao, S F; Ding, Z J

    2012-01-01

    Monte Carlo simulation methods for the study of electron beam interaction with solids have been mostly concerned with specimens of simple geometry. In this article, we propose a simulation algorithm for treating arbitrary complex structures in a real sample. The method is based on a finite element triangular mesh modeling of sample geometry and a space subdivision for accelerating simulation. Simulation of secondary electron image in scanning electron microscopy has been performed for gold particles on a carbon substrate. Comparison of the simulation result with an experiment image confirms that this method is effective to model complex morphology of a real sample.

  8. Imaging of magnetic and electric fields by electron microscopy

    Science.gov (United States)

    Zweck, Josef

    2016-10-01

    Nanostructured materials become more and more a part of our daily life, partly as self-assembled particles or artificially patterned. These nanostructures often possess intrinsic magnetic and/or electric fields which determine (at least partially) their physical properties. Therefore it is important to be able to measure these fields reliably on a nanometre scale. A rather common instrument for the investigation of these fields is the transmission electron microscope as it offers high spatial resolution. The use of an electron microscope to image electric and magnetic fields on a micron down to sub-nanometre scale is treated in detail for transmission electron microscopes (TEM) and scanning transmission electron microscopes (STEM). The formation of contrast is described for the most common imaging modes, the specific advantages and disadvantages of each technique are discussed and examples are given. In addition, the experimental requirements for the use of the techniques described are listed and explained.

  9. Imaging of magnetic and electric fields by electron microscopy.

    Science.gov (United States)

    Zweck, Josef

    2016-10-12

    Nanostructured materials become more and more a part of our daily life, partly as self-assembled particles or artificially patterned. These nanostructures often possess intrinsic magnetic and/or electric fields which determine (at least partially) their physical properties. Therefore it is important to be able to measure these fields reliably on a nanometre scale. A rather common instrument for the investigation of these fields is the transmission electron microscope as it offers high spatial resolution. The use of an electron microscope to image electric and magnetic fields on a micron down to sub-nanometre scale is treated in detail for transmission electron microscopes (TEM) and scanning transmission electron microscopes (STEM). The formation of contrast is described for the most common imaging modes, the specific advantages and disadvantages of each technique are discussed and examples are given. In addition, the experimental requirements for the use of the techniques described are listed and explained.

  10. Characterization of encapsulated quantum dots via electron channeling contrast imaging

    Science.gov (United States)

    Deitz, Julia I.; Carnevale, Santino D.; De Graef, Marc; McComb, David W.; Grassman, Tyler J.

    2016-08-01

    A method for characterization of encapsulated epitaxial quantum dots (QD) in plan-view geometry using electron channeling contrast imaging (ECCI) is presented. The efficacy of the method, which requires minimal sample preparation, is demonstrated with proof-of-concept data from encapsulated (sub-surface) epitaxial InAs QDs within a GaAs matrix. Imaging of the QDs under multiple diffraction conditions is presented, establishing that ECCI can provide effectively identical visualization capabilities as conventional two-beam transmission electron microscopy. This method facilitates rapid, non-destructive characterization of sub-surface QDs giving immediate access to valuable nanostructural information.

  11. Transmission electron microscopy physics of image formation and microanalysis

    CERN Document Server

    Reimer, Ludwig

    1984-01-01

    The aim of this book is to outline the physics of image formation, electron­ specimen interactions and image interpretation in transmission electron mic­ roscopy. The book evolved from lectures delivered at the University of Munster and is a revised version of the first part of my earlier book Elek­ tronenmikroskopische Untersuchungs- und Priiparationsmethoden, omitting the part which describes specimen-preparation methods. In the introductory chapter, the different types of electron microscope are compared, the various electron-specimen interactions and their applications are summarized and the most important aspects of high-resolution, analytical and high-voltage electron microscopy are discussed. The optics of electron lenses is discussed in Chapter 2 in order to bring out electron-lens properties that are important for an understanding of the function of an electron microscope. In Chapter 3, the wave optics of elec­ trons and the phase shifts by electrostatic and magnetic fields are introduced; Fresne...

  12. Determining the effective electron density of hip prosthesis using an electronic portal imaging device

    International Nuclear Information System (INIS)

    A method of determining the effective electron density of hip prostheses using a scanning liquid ionization chamber (SLIC) electronic portal imaging device (EPID) is described. The method involves establishing an empirical relationship between the pixel intensity values (extracted from a portal image) and the corresponding equivalent thickness of an inhomogeneity such as a hip prosthesis. This is done using a composite phantom made of polystyrene with embedded inhomogeneities of aluminum, copper and lead. Results for 6 and 10 MV photons show that the relationship depends on the characteristics of the imaging device and on the photon energy, provided the atomic number (Z) of the inhomogeneity is sufficiently low such that the Compton effect remains the dominant photon interaction. The portal images of a pelvic phantom with prosthesis were then used to provide x-ray attenuation information, which allowed the determination of the equivalent path length containing the inhomogeneity and, therefore, its effective electron density. (author)

  13. Low-Temperature Scanning Capacitance Probe for Imaging Electron Motion

    International Nuclear Information System (INIS)

    Novel techniques to probe electronic properties at the nanoscale can shed light on the physics of nanoscale devices. In particular, studying the scattering of electrons from edges and apertures at the nanoscale and imaging the electron profile in a quantum dot, have been of interest [1]. In this paper, we present the design and implementation of a cooled scanning capacitance probe that operates at liquid He temperatures to image electron waves in nanodevices. The conducting tip of a scanned probe microscope is held above the nanoscale structure, and an applied sample-to-tip voltage creates an image charge that is measured by a cooled charge amplifier [2] adjacent to the tip. The circuit is based on a low-capacitance, high- electron-mobility transistor (Fujitsu FHX35X). The input is a capacitance bridge formed by a low capacitance pinched-off HEMT transistor and tip-sample capacitance. We have achieved low noise level (0.13 e/VHz) and high spatial resolution (100 nm) for this technique, which promises to be a useful tool to study electronic behavior in nanoscale devices

  14. Development of a new electronic neutron imaging system

    International Nuclear Information System (INIS)

    An electronic neutron imaging camera system was developed for use with thermal, epithermal, and fast neutrons in applications that include nondestructive inspection of explosives, corrosion, turbine blades, electronics, low Z components, etc. The neutron images are expected to provide information to supplement that available from X-ray tests. The primary camera image area was a 30x30 cm field-of-view with a spatial resolution approaching 1.6 line pairs/mm (lp/mm). The camera had a remotely changeable second lens to limit the field-of-view to 7.6x7.6 cm for high spatial resolution (at least 4 lp/mm) thermal neutron imaging, but neutron and light scatter will limit resolution for fast neutrons to about 0.5 lp/mm. Remote focus capability enhanced camera set-up for optimum operation. The 75 dB dynamic range camera system included 6Li-based screens for imaging of thermal and epithermal neutrons and ZnS(Ag)-based screens for fast neutron imaging. The fast optics was input to a Super S-25 Gen II image intensifier, fiber optically coupled to a 1134 (h)x486 (v) frame transfer CCD camera. The camera system was designed to be compatible with a Navy-sponsored accelerator neutron source. The planned neutron source is an RF quadrupole accelerator that will provide a fast neutron flux of 107 n/cm2-s (at a source distance of 1 m) at an energy of about 2.2 MeV and a thermal neutron flux of 106 n/cm2-s at a source L/D ratio of 30. The electronic camera produced good quality real-time images at these neutron levels. On-chip integration could be used to improve image quality for low flux situations. The camera and accelerator combination provided a useful non-reactor neutron inspection system

  15. Application of Transmission Electron Backscattered Diffraction in Nanomaterials Research%透射模式电子背散射衍射技术在纳米材料研究中的应用

    Institute of Scientific and Technical Information of China (English)

    刘紫微; 华佳捷; 林初城; 姜彩芬; 曾毅

    2015-01-01

    为了提高电子背散射衍射技术的空间分辨率,使之能够对纳米尺度的晶粒或超细粉末进行相鉴定和取向分析,本研究通过自主设计的透射模式电子背散射衍射技术的样品台,及调整EBSD探头位置及角度,收集到清晰、完整的透射电子菊池衍射花样。研究了减薄块体样品厚度对透射电子菊池衍射花样的影响,对减薄氧化锆涂层样品进行了t-EBSD面分布分析,其结果的平均角度偏差(MAD)值仅为0.38,成功鉴定出小于30 nm尺度的纳米氧化锆涂层立方相;将超声分散后的纳米TiO2粉体滴在铜网上,采用t-EBSD对纳米颗粒进行点分析,成功鉴定了锐钛矿相和金红石相TiO2,其中纳米锐钛矿TiO2粉体的最小尺寸为20 nm左右,使得扫描电镜中相鉴定的最小分辨率从目前的约100 nm提高到小于30 nm,大大拓展了电子背散射衍射技术在纳米材料研究中的应用范围。%To improve the spatial resolution of electron backscatter diffraction technique, by which phase identification and orientation analysis of the nano scale grain or ultrafine powders can be achieved, a special specimen holder for transmission electron backscatter diffraction techniques (t-EBSD) accompanied by adjusting position and angle of EBSD detector, was newly designed. The new sample holder could fix the STEM samples, enabling clear TEM Kiku-chi diffraction patterns to be successfully collected by EBSD detector. Then the effect of sample thickness on Kikuchi diffraction pattern was investigated. Based on the newly designed holder, the t-EBSD mapping of zirconia coating was acquired with the mean angle deviation (MAD) at only 0.38, successfully identified the cubic phase of less than 30 nm zirconia coating. Put the ultrasonic dispersed TiO2 powder on copper mesh, the point analysis of t-EBSD could identify the anatase and the rutile of TiO2, distinguishing minimum size of anatase phase TiO2less than 20 nm. Therefore, the minimum

  16. Interlinking backscatter, grain size and benthic community structure

    Science.gov (United States)

    McGonigle, Chris; Collier, Jenny S.

    2014-06-01

    The relationship between acoustic backscatter, sediment grain size and benthic community structure is examined using three different quantitative methods, covering image- and angular response-based approaches. Multibeam time-series backscatter (300 kHz) data acquired in 2008 off the coast of East Anglia (UK) are compared with grain size properties, macrofaunal abundance and biomass from 130 Hamon and 16 Clamshell grab samples. Three predictive methods are used: 1) image-based (mean backscatter intensity); 2) angular response-based (predicted mean grain size), and 3) image-based (1st principal component and classification) from Quester Tangent Corporation Multiview software. Relationships between grain size and backscatter are explored using linear regression. Differences in grain size and benthic community structure between acoustically defined groups are examined using ANOVA and PERMANOVA+. Results for the Hamon grab stations indicate significant correlations between measured mean grain size and mean backscatter intensity, angular response predicted mean grain size, and 1st principal component of QTC analysis (all p response predicted mean grain size (r2 = 0.692; p response predicted grain size (p < 0.001), and QTC class (p = 0.009). Mean grain size (Clamshell) shows a significant difference between groups for mean backscatter (p = 0.001); other methods were not significant. PERMANOVA for the Hamon abundance shows benthic community structure was significantly different between acoustic groups for all methods (p ≤ 0.001). Overall these results show considerable promise in that more than 60% of the variance in the mean grain size of the Clamshell grab samples can be explained by mean backscatter or acoustically-predicted grain size. These results show that there is significant predictive capacity for sediment characteristics from multibeam backscatter and that these acoustic classifications can have ecological validity.

  17. Imaging of tissue sections with very slow electrons

    Energy Technology Data Exchange (ETDEWEB)

    Frank, L., E-mail: ludek@isibrno.cz [Institute of Scientific Instruments AS CR, v.v.i., Královopolská 147, 61264 Brno (Czech Republic); Nebesářová, J.; Vancová, M. [Biology Centre AS CR, v.v.i., Branišovská 31, 37005 České Budějovice (Czech Republic); Paták, A.; Müllerová, I. [Institute of Scientific Instruments AS CR, v.v.i., Královopolská 147, 61264 Brno (Czech Republic)

    2015-01-15

    The examination of thin sections of tissues with electron microscopes is an indispensable tool. Being composed of light elements, samples of living matter illuminated with electrons at the usual high energies of tens or even hundreds of kiloelectronvolts provide very low image contrasts in transmission or scanning transmission electron microscopes. Therefore, heavy metal salts are added to the specimen during preparation procedures (post-fixation with osmium tetroxide or staining). However, these procedures can modify or obscure the ultrastructural details of cells. Here we show that the energy of electrons used for the scanned transmission imaging of tissue sections can be reduced to mere hundreds or even tens of electronvolts and can produce extremely high contrast even for samples free of any metal salts. We found that when biasing a sufficiently thin tissue section sample to a high negative potential in a scanning transmission electron microscope, thereby reducing the energy of the electrons landing on the sample, and collecting the transmitted electrons with a grounded detector, we obtain a high contrast revealing structure details not enhanced by heavy atoms. Moreover, bombardment with slow electrons sensitively depolymerises the resin in which the tissue is embedded, thereby enhancing the transmitted signal with no observable loss of structure details. The use of low-energy electrons requires ultrathin sections of a thickness of less than 10 nm, but their preparation is now possible. Ultralow energy STEM provides a tool enabling the observation of very thin biological samples without any staining. This method should also be advantageous for examination of 2D crystals, thin films of polymers, polymer blends, etc. - Highlights: • Sections of a thickness below 10 nm were imaged in STEM at hundreds and tens of eV. • Image contrast grows steeply with decreasing electron energy in the STEM. • Very slow electrons provide high contrast for samples free of

  18. 2D electron cyclotron emission imaging at ASDEX Upgrade (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Classen, I. G. J. [Max Planck Institut fuer Plasmaphysik, 85748 Garching (Germany); FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Boom, J. E.; Vries, P. C. de [FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Suttrop, W.; Schmid, E.; Garcia-Munoz, M.; Schneider, P. A. [Max Planck Institut fuer Plasmaphysik, 85748 Garching (Germany); Tobias, B.; Domier, C. W.; Luhmann, N. C. Jr. [University of California at Davis, Davis, California 95616 (United States); Donne, A. J. H. [FOM-Institute for Plasma Physics, Rijnhuizen, 3430 BE Nieuwegein (Netherlands); Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Jaspers, R. J. E. [Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands); Park, H. K. [POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of); Munsat, T. [University of Colorado, Boulder, Colorado 80309 (United States)

    2010-10-15

    The newly installed electron cyclotron emission imaging diagnostic on ASDEX Upgrade provides measurements of the 2D electron temperature dynamics with high spatial and temporal resolution. An overview of the technical and experimental properties of the system is presented. These properties are illustrated by the measurements of the edge localized mode and the reversed shear Alfven eigenmode, showing both the advantage of having a two-dimensional (2D) measurement, as well as some of the limitations of electron cyclotron emission measurements. Furthermore, the application of singular value decomposition as a powerful tool for analyzing and filtering 2D data is presented.

  19. Development of a new electronic neutron imaging system

    CERN Document Server

    Brenizer, J S; Gibbs, K M; Mengers, P; Stebbings, C T; Polansky, D; Rogerson, D J

    1999-01-01

    An electronic neutron imaging camera system was developed for use with thermal, epithermal, and fast neutrons in applications that include nondestructive inspection of explosives, corrosion, turbine blades, electronics, low Z components, etc. The neutron images are expected to provide information to supplement that available from X-ray tests. The primary camera image area was a 30x30 cm field-of-view with a spatial resolution approaching 1.6 line pairs/mm (lp/mm). The camera had a remotely changeable second lens to limit the field-of-view to 7.6x7.6 cm for high spatial resolution (at least 4 lp/mm) thermal neutron imaging, but neutron and light scatter will limit resolution for fast neutrons to about 0.5 lp/mm. Remote focus capability enhanced camera set-up for optimum operation. The 75 dB dynamic range camera system included sup 6 Li-based screens for imaging of thermal and epithermal neutrons and ZnS(Ag)-based screens for fast neutron imaging. The fast optics was input to a Super S-25 Gen II image intensifi...

  20. Image process in imaging through a scattering medium using fs electronic holography

    Institute of Scientific and Technical Information of China (English)

    侯比学; 陈国夫

    1999-01-01

    Aimed at imaging technology through scattering medium using fs electronic holography, a set of image process algorithm is put forward. This algorithm can be divided into three stages. First, every hologram is pre-processed, whose contrast is enhanced. Second, the first-order spatial spectrum is low-pass-filtered through a two-step process, so that high-frequency noise can be removed. Finally, many reconstructed images are ensemble-averaged. This stage can smooth random noise and is advantageous to restraining the speckle noise of image. The operation of this algorithm shows that all of processes in the three stages have obvious effects on improving image quality.

  1. A Document Imaging Technique for Implementing Electronic Loan Approval Process

    Directory of Open Access Journals (Sweden)

    J. Manikandan

    2015-04-01

    Full Text Available The image processing is one of the leading technologies of computer applications. Image processing is a type of signal processing, the input for image processor is an image or video frame and the output will be an image or subset of image [1]. Computer graphics and computer vision process uses an image processing techniques. Image processing systems are used in various environments like medical fields, computer-aided design (CAD, research fields, crime investigation fields and military fields. In this paper, we proposed a document image processing technique, for establishing electronic loan approval process (E-LAP [2]. Loan approval process has been tedious process, the E-LAP system attempts to reduce the complexity of loan approval process. Customers have to login to fill the loan application form online with all details and submit the form. The loan department then processes the submitted form and then sends an acknowledgement mail via the E-LAP to the requested customer with the details about list of documents required for the loan approval process [3]. The approaching customer can upload the scanned copies of all required documents. All this interaction between customer and bank take place using an E-LAP system.

  2. 77 FR 38829 - Certain Electronic Imaging Devices; Institution of Investigation

    Science.gov (United States)

    2012-06-29

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Electronic Imaging Devices; Institution of Investigation AGENCY: U.S. International Trade.... International Trade Commission on May 23, 2012, under section 337 of the Tariff Act of 1930, as amended, 19...

  3. Time-resolved tomographic images of a relativistic electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Koehler, H.A.; Jacoby, B.A.; Nelson, M.

    1984-07-01

    We obtained a sequential series of time-resolved tomographic two-dimensional images of a 4.5-MeV, 6-kA, 30-ns electron beam. Three linear fiber-optic arrays of 30 or 60 fibers each were positioned around the beam axis at 0/sup 0/, 61/sup 0/, and 117/sup 0/. The beam interacting with nitrogen at 20 Torr emitted light that was focused onto the fiber arrays and transmitted to a streak camera where the data were recorded on film. The film was digitized, and two-dimensional images were reconstructed using the maximum-entropy tomographic technique. These images were then combined to produce an ultra-high-speed movie of the electron-beam pulse.

  4. Nanodiamond Landmarks for Subcellular Multimodal Optical and Electron Imaging

    CERN Document Server

    Zurbuchen, Mark A; Kohan, Sirus A; Leung, Belinda; Bouchard, Louis-S

    2015-01-01

    There is a growing need for biolabels that can be used in both optical and electron microscopies, are non-cytotoxic, and do not photobleach. Such biolabels could enable targeted nanoscale imaging of sub-cellular structures, and help to establish correlations between conjugation-delivered biomolecules and function. Here we demonstrate a subcellular multi-modal imaging methodology that enables localization of inert particulate probes, consisting of nanodiamonds having fluorescent nitrogen-vacancy centers. These are functionalized to target specific structures, and are observable by both optical and electron microscopies. Nanodiamonds targeted to the nuclear pore complex are rapidly localized in electron-microscopy diffraction mode to enable "zooming-in" to regions of interest for detailed structural investigations. Optical microscopies reveal nanodiamonds for in-vitro tracking or uptake-confirmation. The approach is general, works down to the single nanodiamond level, and can leverage the unique capabilities of...

  5. Understanding the radar backscattering from flooded and nonflooded Amazonian forests: results from canopy backscatter modeling

    International Nuclear Information System (INIS)

    To understand the potential of using multiwavelength imaging radars to detect flooding in Amazonian floodplain forests, we simulated the radar backscatter from a floodplain forest with a flooded or nonflooded ground condition at C-, L-, and P-bands. Field measurements of forest structure in the Anavilhanas archipelago of the Negro River, Brazil, were used as inputs to the model. Given the same wavelength or incidence angle, the ratio of backscatter from the flooded forest to that from the nonflooded forest was higher at HH polarization than at VV polarization. Given the same wavelength or polarization, the ratio was larger at small incidence angles than at large incidence angles. Given the same polarization or incidence angle, the ratio was larger at a long wavelength than at a short wavelength. As the surface soil moisture underneath the nonflooded forest increased from 10% to 50% of volumetric moisture, the flooded/nonflooded backscatter ratio decreased; the decreases were small at C- and L-band but large at P-band. When the leaf size was comparable to or larger than the wavelength of C-band, the leaf area index (LAI) had a large effect on the simulated C-band (not L-band or P-band) backscatter from the flooded and nonflooded forests. (author)

  6. Electron temperature fluctuation in the HT-7 tokamak plasma observed by electron cyclotron emission imaging

    Institute of Scientific and Technical Information of China (English)

    Xu Xiao-Yuan; Wang Jun; Yu Yi; Wen Yi-Zhi; Yu Chang-Xuan; Liu Wan-Dong; Wan Bao-Nian; Gao Xiang; N. C. Luhmann; C. W. Domier; Jian Wang; Z. G. Xia; Zuowei Shen

    2009-01-01

    The fluctuation of the electron temperature has been measured by using the electron cyclotron emission imaging in the Hefei Tokamak-7 (HT-7) plasma. The electron temperature fluctuation with a broadband spectrum shows that it propagates in the electron diamagnetic drift direction, and the mean poloidal wave-number kg is calculated to be about 1.58 cm-1, or keps ≈0.34. It indicates that the fluctuation should come from the electron drift wave turbulence. The linear global scaling of the electron temperature fluctuation with the gradient of electron temperature is consistent with the mixing length scale qualitatively. Evolution of spectrum of the fluctuation during the sawtooth oscillation phases is investigated, and the fluctuation is found to increase with the gradient of electron temperature increasing during most phases of the sawtooth oscillation. The results indicate that the electron temperature gradient is probably the driver of the fluctuation enhancement. The steady heat flux driven by electron temperature fluctuation is estimated and compared with the results from power balance estimation.

  7. Electron Microscopy and Image Analysis for Selected Materials

    Science.gov (United States)

    Williams, George

    1999-01-01

    This particular project was completed in collaboration with the metallurgical diagnostics facility. The objective of this research had four major components. First, we required training in the operation of the environmental scanning electron microscope (ESEM) for imaging of selected materials including biological specimens. The types of materials range from cyanobacteria and diatoms to cloth, metals, sand, composites and other materials. Second, to obtain training in surface elemental analysis technology using energy dispersive x-ray (EDX) analysis, and in the preparation of x-ray maps of these same materials. Third, to provide training for the staff of the metallurgical diagnostics and failure analysis team in the area of image processing and image analysis technology using NIH Image software. Finally, we were to assist in the sample preparation, observing, imaging, and elemental analysis for Mr. Richard Hoover, one of NASA MSFC's solar physicists and Marshall's principal scientist for the agency-wide virtual Astrobiology Institute. These materials have been collected from various places around the world including the Fox Tunnel in Alaska, Siberia, Antarctica, ice core samples from near Lake Vostoc, thermal vents in the ocean floor, hot springs and many others. We were successful in our efforts to obtain high quality, high resolution images of various materials including selected biological ones. Surface analyses (EDX) and x-ray maps were easily prepared with this technology. We also discovered and used some applications for NIH Image software in the metallurgical diagnostics facility.

  8. Quantitative analysis of mouse corpus callosum from electron microscopy images

    Directory of Open Access Journals (Sweden)

    Kathryn L. West

    2015-12-01

    Full Text Available This article provides morphometric analysis of 72 electron microscopy images from control (n=4 and hypomyelinated (n=2 mouse corpus callosum. Measures of axon diameter and g-ratio were tabulated across all brains from two regions of the corpus callosum and a non-linear relationship between axon diameter and g-ratio was observed. These data are related to the accompanying research article comparing multiple methods of measuring g-ratio entitled ‘A revised model for estimating g-ratio from MRI’ (West et al., NeuroImage, 2015.

  9. Adaptive noise Wiener filter for scanning electron microscope imaging system.

    Science.gov (United States)

    Sim, K S; Teh, V; Nia, M E

    2016-03-01

    Noise on scanning electron microscope (SEM) images is studied. Gaussian noise is the most common type of noise in SEM image. We developed a new noise reduction filter based on the Wiener filter. We compared the performance of this new filter namely adaptive noise Wiener (ANW) filter, with four common existing filters as well as average filter, median filter, Gaussian smoothing filter and the Wiener filter. Based on the experiments results the proposed new filter has better performance on different noise variance comparing to the other existing noise removal filters in the experiments. SCANNING 38:148-163, 2016. © 2015 Wiley Periodicals, Inc. PMID:26235517

  10. Ultrafast Molecular Imaging by Laser Induced Electron Diffraction

    CERN Document Server

    Peters, Michel; Cornaggia, Christian; Saugout, Sébastien; Charron, Eric; Keller, Arne; Atabek, Osman

    2010-01-01

    We address the feasibility of imaging geometric and orbital structure of a polyatomic molecule on an attosecond time-scale using the Laser Induced Electron Diffraction, LIED, technique [T. Zuo \\textit{et al.}, Chem. Phys. Lett. \\textbf{259}, 313 (1996)]. We present numerical results obtained for the CO$_2$ molecule using a single active electron model. The molecular geometry (bond-lengths) is determined within 3% of accuracy from a diffraction pattern which also reflects the nodal properties of the initial molecular orbital. Robustness of the structure determination is discussed with respect to vibrational and rotational motions with a complete interpretation of the laser-induced mechanisms.

  11. Image simulations of kinked vortices for transmission electron microscopy

    DEFF Research Database (Denmark)

    Beleggia, Marco; Pozzi, G.; Tonomura, A.

    2010-01-01

    We present an improved model of kinked vortices in high-Tc superconductors suitable for the interpretation of Fresnel or holographic observations carried out with a transmission electron microscope. A kinked vortex is composed of two displaced half-vortices, perpendicular to the film plane...... observations of high-Tc superconducting films, where the Fresnel contrast associated with some vortices showed a dumbbell like appearance. Here, we show that under suitable conditions the JV segment may reveal itself in Fresnel imaging or holographic phase mapping in a transmission electron microscope....

  12. Revealing Dissociative Electron Attachment Dynamics in Polyatomic Molecules Using Momentum Imaging Experiments and Electron Scattering Calculations

    Science.gov (United States)

    Belkacem, Ali; Slaughter, Daniel

    2015-05-01

    Understanding electron-driven chemical reactions is important for improving a variety of technological applications such as materials processing and the important role they play in the radiation damage in bulk matter. Furthermore, dissociative electron attachment often exhibits site-selective bond cleavage, which holds promise for prediction and precise control of electron-driven chemical reactions. Recent dynamical studies of these reactions have demonstrated that an understanding of anion dissociation dynamics beyond simple one-dimensional models is crucial in interpreting the measured fragment angular distributions. We combine ion fragment momentum imaging experiments with electron attachment entrance amplitude calculations to interrogate the non-Born-Oppenheimer dynamics of dissociative electron attachment in polyatomic molecules. We will report recent experimental developments in molecules of technological interest including methanol, methane and uracil. Work supported by Chemical Sciences, Geosciences and Biosciences division of BES/DOE.

  13. Flux maximization techniques for compton backscatter depth profilometry.

    Science.gov (United States)

    Lawson, L

    1993-01-01

    Resolution in x-ray backscatter imaging has often been hampered by low fluxes. But, for a given set of resolution requirements and geometric constraints, it is possible to define a maximization problem in the geometric parameters for which the solution is the maximum flux possible in those circumstances. In this way, resolution in noncritical directions can be traded for improved resolution in a desired direction. Making this the thickness, or surface normal direction, makes practicable the depth profiling of layered structures. Such techniques were applied to the problem of imaging the layered structure of corroding aircraft sheet metal joints using Compton backscatter. PMID:21307450

  14. Reconstruction of images from radiofrequency electron paramagnetic resonance spectra.

    Science.gov (United States)

    Smith, C M; Stevens, A D

    1994-12-01

    This paper discusses methods for obtaining image reconstructions from electron paramagnetic resonance (EPR) spectra which constitute object projections. An automatic baselining technique is described which treats each spectrum consistently; rotating the non-horizontal baselines which are caused by stray magnetic effects onto the horizontal axis. The convolved backprojection method is described for both two- and three-dimensional reconstruction and the effect of cut-off frequency on the reconstruction is illustrated. A slower, indirect, iterative method, which does a non-linear fit to the projection data, is shown to give a far smoother reconstructed image when the method of maximum entropy is used to determine the value of the final residual sum of squares. Although this requires more computing time than the convolved backprojection method, it is more flexible and overcomes the problem of numerical instability encountered in deconvolution. Images from phantom samples in vitro are discussed. The spectral data for these have been accumulated quickly and have a low signal-to-noise ratio. The results show that as few as 16 spectra can still be processed to give an image. Artifacts in the image due to a small number of projections using the convolved backprojection reconstruction method can be removed by applying a threshold, i.e. only plotting contours higher than a given value. These artifacts are not present in an image which has been reconstructed by the maximum entropy technique. At present these techniques are being applied directly to in vivo studies.

  15. Carrier-envelope phase-tagged imaging of the controlled electron acceleration from SiO2 nanospheres in intense few-cycle laser fields

    Science.gov (United States)

    Zherebtsov, S.; Süßmann, F.; Peltz, C.; Plenge, J.; Betsch, K. J.; Znakovskaya, I.; Alnaser, A. S.; Johnson, N. G.; Kübel, M.; Horn, A.; Mondes, V.; Graf, C.; Trushin, S. A.; Azzeer, A.; Vrakking, M. J. J.; Paulus, G. G.; Krausz, F.; Rühl, E.; Fennel, T.; Kling, M. F.

    2012-07-01

    Waveform-controlled light fields offer the possibility of manipulating ultrafast electronic processes on sub-cycle timescales. The optical lightwave control of the collective electron motion in nanostructured materials is key to the design of electronic devices operating at up to petahertz frequencies. We have studied the directional control of the electron emission from 95 nm diameter SiO2 nanoparticles in few-cycle laser fields with a well-defined waveform. Projections of the three-dimensional (3D) electron momentum distributions were obtained via single-shot velocity-map imaging (VMI), where phase tagging allowed retrieving the laser waveform for each laser shot. The application of this technique allowed us to efficiently suppress background contributions in the data and to obtain very accurate information on the amplitude and phase of the waveform-dependent electron emission. The experimental data that are obtained for 4 fs pulses centered at 720 nm at different intensities in the range (1-4) × 1013 W cm-2 are compared to quasi-classical mean-field Monte-Carlo simulations. The model calculations identify electron backscattering from the nanoparticle surface in highly dynamical localized fields as the main process responsible for the energetic electron emission from the nanoparticles. The local field sensitivity of the electron emission observed in our studies can serve as a foundation for future research on propagation effects for larger particles and field-induced material changes at higher intensities.

  16. NANP1M.TIF - North Anacapa Passage sidescan sonar backscatter image in nearshore Benthic Habitat mapping Project S. California map Series. (UTM 10N, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The sidescan sonar image of the nearshore seafloor (0 to 100 m water depths) of the North Anacapa Passage area was mosaicked from data collected in 2000. A Klein...

  17. SANA1M.TIF - South Anacapa Island sidescan sonar backscatter image in nearshore Benthic Habitat mapping Project S. California map Series. (UTM 10N, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The sidescan sonar image of the nearshore seafloor (0 to 100 m water depths) of the South Anacapa area was mosaicked from data collected in 1999 and 2000. A Klein...

  18. BSYC1M.TIF - Big Sycamore Reserve sidescan sonar backscatter image in the Nearshore Benthic Habitat Mapping Project S. California map series. (UTM 11N, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The sidescan sonar image of the nearshore seafloor (0 to 100 m water depths) of the Big Sycamore reserve area was mosaicked from data collected in 1998. A Klein...

  19. SANP1M.TIF - South Anacapa Passage sidescan sonar backscatter image in nearshore Benthic Habitat mapping Project S. California map Series. (UTM 10N, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The sidescan sonar image of the nearshore seafloor (0 to 100 m water depths) of the southern Anacapa Passage area was mosaicked from data collected in 1999 and...

  20. SECRU1M.TIF - Southeast Santa Cruz sidescan sonar backscatter image in nearshore Benthic Habitat mapping Project S. California map Series. (UTM 10N, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The sidescan sonar image of the nearshore seafloor (0 to 100 m water depths) of the Southeast Santa Cruz area was mosaicked from data collected in 1999. A Klein...

  1. NANA1M.TIF - Anacapa Island Reserve sidescan sonar backscatter image in nearshore Benthic Habitat mapping Project S. California map Series. (UTM 10N, NAD83)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The sidescan sonar image of the nearshore seafloor (0 to 100 m water depths) of the Big Sycamore reserve area was mosaicked from data collected in 1998. A Klein...

  2. Analysis of forest backscattering characteristics based on polarization coherence tomography

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    It is difficult to make an inventory of vertical profiles of forest structure parameters in field measurements.However,analysis and understanding of forest backscattering characteristics contribute to estimation and detection of forest vertical structure because of the close relationships between backscattering characteristics and structure parameters.The vertical structure function in the complex interferometric coherence definition,which represents the vertical variation of microwave scattering with the penetration depth at a point in the 2-D radar image and can be used to analyze the forest backscattering characteristics,can be reconstructed from polarization coherence tomography(PCT).Based on PCT,the paper analyzes the forest backscattering characteristics and explores the inherent relationship between the result of PCT and the forest structure parameters from numerical simulation of Random Volume over Ground model(RVoG),Polarimetric SAR interferometry(PolInSAR)simulation of forest scene and PolInSAR data at L-band of the test site Traunstein.Firstly,the effects of the extinction coefficient and surface-to-volume scattering ratio in RVoG model on vertical backscattering characteristics are analyzed by means of numerical simulation.Secondly,by applying PCT to L-band POLInSAR simulations of forest scene,different variations of vertical backscattering due to different extinction coefficients and the ratios of surface-to-volume scattering resulting from different polarizations,forest types and densities are displayed and analyzed.Then a concept of relative average backscattering intensity is presented,and the factors which affect its vertical distribution are also discussed.Preliminary results show that there is high sensitivity of the vertical distribution of forest relative average backscattering intensity to the polarization,forest type and density.Finally,based on repeat pass DLR E-SAR L-band airborne POLInSAR data,the capability of PCT technology for detection

  3. The use of combined three-dimensional electron backscatter diffraction and energy dispersive X-ray analysis to assess the characteristics of the gamma/gamma-prime microstructure in alloy 720Li Trade-Mark-Sign

    Energy Technology Data Exchange (ETDEWEB)

    Child, D.J., E-mail: d.child@lboro.ac.uk [Department of Materials, Loughborough University, Loughborough, Leicestershire, LE11 3TU (United Kingdom); West, G.D., E-mail: g.west@lboro.ac.uk [Department of Materials, Loughborough University, Loughborough, Leicestershire, LE11 3TU (United Kingdom); Thomson, R.C., E-mail: r.c.thomson@lboro.ac.uk [Department of Materials, Loughborough University, Loughborough, Leicestershire, LE11 3TU (United Kingdom)

    2012-03-15

    Multiple three-dimensional reconstructions of a {gamma}/{gamma} Prime phase structure in Alloy 720Li have been carried out by employing a serial milling technique with simultaneous electron backscatter diffraction (EBSD) and energy dispersive x-ray (EDX) analysis data collection. Combining EBSD data with EDX is critical in obtaining maps to distinguish between the chemically differing, but crystallographically similar {gamma} and {gamma} Prime phases present in the alloy studied. EDX is shown to allow the differentiation of {gamma} and {gamma} Prime phases, with EBSD providing increased grain shape accuracy. The combination of data sources also allowed identification of coherent {gamma}/{gamma} Prime phase interfaces that would not be identified using solely EBSD or EDX. The study identifies a region of grain banding within the alloy, which provides the basis for a three-dimensional comparison and discussion of {gamma} Prime phase size between coarse and fine grain regions, whilst also identifying coherent {gamma} Prime phase interfaces, possible only using both EDX and EBSD systems simultaneously. The majority of the {gamma} Prime phase lies in the range of 1-10 {mu}m in non-banded regions, with a detectable particle size limit of 500 nm being established. The validity of the reconstruction has been demonstrated using an electron interaction volumes model, and an assessment of the validity of EBSD and EDX data sources is discussed showing {gamma} Prime phase connectivity in all dimensions. -- Highlights: Black-Right-Pointing-Pointer Use of combined EBSD/EDX for the 3D analysis of gamma prime in a Ni-based alloy. Black-Right-Pointing-Pointer Assessment of 3D reconstruction accuracy using CASINO. Black-Right-Pointing-Pointer Observation and validation of gamma prime phase connectivity throughout the alloy. Black-Right-Pointing-Pointer Identification and characterisation of grain banding in gamma prime. Black-Right-Pointing-Pointer Distinction of phase coherency

  4. Low energy electron point source microscopy: beyond imaging

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, Andre; Goelzhaeuser, Armin [Physics of Supramolecular Systems and Surfaces, University of Bielefeld, Postfach 100131, 33501 Bielefeld (Germany)

    2010-09-01

    Low energy electron point source (LEEPS) microscopy has the capability to record in-line holograms at very high magnifications with a fairly simple set-up. After the holograms are numerically reconstructed, structural features with the size of about 2 nm can be resolved. The achievement of an even higher resolution has been predicted. However, a number of obstacles are known to impede the realization of this goal, for example the presence of electric fields around the imaged object, electrostatic charging or radiation induced processes. This topical review gives an overview of the achievements as well as the difficulties in the efforts to shift the resolution limit of LEEPS microscopy towards the atomic level. A special emphasis is laid on the high sensitivity of low energy electrons to electrical fields, which limits the structural determination of the imaged objects. On the other hand, the investigation of the electrical field around objects of known structure is very useful for other tasks and LEEPS microscopy can be extended beyond the task of imaging. The determination of the electrical resistance of individual nanowires can be achieved by a proper analysis of the corresponding LEEPS micrographs. This conductivity imaging may be a very useful application for LEEPS microscopes. (topical review)

  5. Advanced electron crystallography through model-based imaging.

    Science.gov (United States)

    Van Aert, Sandra; De Backer, Annick; Martinez, Gerardo T; den Dekker, Arnold J; Van Dyck, Dirk; Bals, Sara; Van Tendeloo, Gustaaf

    2016-01-01

    The increasing need for precise determination of the atomic arrangement of non-periodic structures in materials design and the control of nanostructures explains the growing interest in quantitative transmission electron microscopy. The aim is to extract precise and accurate numbers for unknown structure parameters including atomic positions, chemical concentrations and atomic numbers. For this purpose, statistical parameter estimation theory has been shown to provide reliable results. In this theory, observations are considered purely as data planes, from which structure parameters have to be determined using a parametric model describing the images. As such, the positions of atom columns can be measured with a precision of the order of a few picometres, even though the resolution of the electron microscope is still one or two orders of magnitude larger. Moreover, small differences in average atomic number, which cannot be distinguished visually, can be quantified using high-angle annular dark-field scanning transmission electron microscopy images. In addition, this theory allows one to measure compositional changes at interfaces, to count atoms with single-atom sensitivity, and to reconstruct atomic structures in three dimensions. This feature article brings the reader up to date, summarizing the underlying theory and highlighting some of the recent applications of quantitative model-based transmisson electron microscopy. PMID:26870383

  6. Photon Counting Imaging with an Electron-Bombarded Pixel Image Sensor.

    Science.gov (United States)

    Hirvonen, Liisa M; Suhling, Klaus

    2016-01-01

    Electron-bombarded pixel image sensors, where a single photoelectron is accelerated directly into a CCD or CMOS sensor, allow wide-field imaging at extremely low light levels as they are sensitive enough to detect single photons. This technology allows the detection of up to hundreds or thousands of photon events per frame, depending on the sensor size, and photon event centroiding can be employed to recover resolution lost in the detection process. Unlike photon events from electron-multiplying sensors, the photon events from electron-bombarded sensors have a narrow, acceleration-voltage-dependent pulse height distribution. Thus a gain voltage sweep during exposure in an electron-bombarded sensor could allow photon arrival time determination from the pulse height with sub-frame exposure time resolution. We give a brief overview of our work with electron-bombarded pixel image sensor technology and recent developments in this field for single photon counting imaging, and examples of some applications. PMID:27136556

  7. Photon Counting Imaging with an Electron-Bombarded Pixel Image Sensor

    Directory of Open Access Journals (Sweden)

    Liisa M. Hirvonen

    2016-04-01

    Full Text Available Electron-bombarded pixel image sensors, where a single photoelectron is accelerated directly into a CCD or CMOS sensor, allow wide-field imaging at extremely low light levels as they are sensitive enough to detect single photons. This technology allows the detection of up to hundreds or thousands of photon events per frame, depending on the sensor size, and photon event centroiding can be employed to recover resolution lost in the detection process. Unlike photon events from electron-multiplying sensors, the photon events from electron-bombarded sensors have a narrow, acceleration-voltage-dependent pulse height distribution. Thus a gain voltage sweep during exposure in an electron-bombarded sensor could allow photon arrival time determination from the pulse height with sub-frame exposure time resolution. We give a brief overview of our work with electron-bombarded pixel image sensor technology and recent developments in this field for single photon counting imaging, and examples of some applications.

  8. Efecto de la distribución superficial de potencial eléctrico en GaAs, debida a un potencial eléctrico externo, sobre imágenes de electrones secundarios en microscopía electrónica de barrido

    Directory of Open Access Journals (Sweden)

    David A. Miranda

    2011-06-01

    Full Text Available The effects upon the images of secondary electrons, back-scattered electrons and energy dispersive spectroscopy (EDS spectrum, due to an external electrical potential applied to a GaAs semiconductor surface, were studied. The potential distribution over the semiconductor surface was modeled by finite elements. Significant similarities between the model and secondary electrons images were observed. The results show that the GaAs surface electrical potential distribution affects the images of secondary electrons, but it does not affect the images of neither the backscattering electrons nor the EDS.

  9. Non-destructive imaging of buried electronic interfaces using a decelerated scanning electron beam.

    Science.gov (United States)

    Hirohata, Atsufumi; Yamamoto, Yasuaki; Murphy, Benedict A; Vick, Andrew J

    2016-01-01

    Recent progress in nanotechnology enables the production of atomically abrupt interfaces in multilayered junctions, allowing for an increase in the number of transistors in a processor. However, uniform electron transport has not yet been achieved across the entire interfacial area in junctions due to the existence of local defects, causing local heating and reduction in transport efficiency. To date, junction uniformity has been predominantly assessed by cross-sectional transmission electron microscopy, which requires slicing and milling processes that can potentially introduce additional damage and deformation. It is therefore essential to develop an alternative non-destructive method. Here we show a non-destructive technique using scanning electron microscopy to map buried junction properties. By controlling the electron-beam energy, we demonstrate the contrast imaging of local junction resistances at a controlled depth. This technique can be applied to any buried junctions, from conventional semiconductor and metal devices to organic devices. PMID:27586090

  10. Non-destructive imaging of buried electronic interfaces using a decelerated scanning electron beam

    Science.gov (United States)

    Hirohata, Atsufumi; Yamamoto, Yasuaki; Murphy, Benedict A.; Vick, Andrew J.

    2016-09-01

    Recent progress in nanotechnology enables the production of atomically abrupt interfaces in multilayered junctions, allowing for an increase in the number of transistors in a processor. However, uniform electron transport has not yet been achieved across the entire interfacial area in junctions due to the existence of local defects, causing local heating and reduction in transport efficiency. To date, junction uniformity has been predominantly assessed by cross-sectional transmission electron microscopy, which requires slicing and milling processes that can potentially introduce additional damage and deformation. It is therefore essential to develop an alternative non-destructive method. Here we show a non-destructive technique using scanning electron microscopy to map buried junction properties. By controlling the electron-beam energy, we demonstrate the contrast imaging of local junction resistances at a controlled depth. This technique can be applied to any buried junctions, from conventional semiconductor and metal devices to organic devices.

  11. Ultrasonic backscatter from cancellous bone: the apparent backscatter transfer function.

    Science.gov (United States)

    Hoffmeister, Brent K; Mcpherson, Joseph A; Smathers, Morgan R; Spinolo, P Luke; Sellers, Mark E

    2015-12-01

    Ultrasonic backscatter techniques are being developed to detect changes in cancellous bone caused by osteoporosis. Many techniques are based on measurements of the apparent backscatter transfer function (ABTF), which represents the backscattered power from bone corrected for the frequency response of the measurement system. The ABTF is determined from a portion of the backscatter signal selected by an analysis gate of width τw delayed by an amount τd from the start of the signal. The goal of this study was to characterize the ABTF for a wide range of gate delays (1 μs ≤ τd ≤ 6 μs) and gate widths (1 μs ≤ τw ≤ 6 μs). Measurements were performed on 29 specimens of human cancellous bone in the frequency range 1.5 to 6.0 MHz using a broadband 5-MHz transducer. The ABTF was found to be an approximately linear function of frequency for most choices of τd and τw. Changes in τd and τw caused the frequency-averaged ABTF [quantified by apparent integrated backscatter (AIB)] and the frequency dependence of the ABTF [quantified by frequency slope of apparent backscatter (FSAB)] to change by as much as 24.6 dB and 6.7 dB/MHz, respectively. τd strongly influenced the measured values of AIB and FSAB and the correlation of AIB with bone density (-0.95 ≤ R ≤ +0.68). The correlation of FSAB with bone density was influenced less strongly by τd (-0.97 ≤ R ≤ -0.87). τw had a weaker influence than τd on the measured values of AIB and FSAB and the correlation of these parameters with bone density.

  12. Low-voltage coherent electron imaging based on a single-atom electron

    CERN Document Server

    Chang, Wei-Tse; Hsu, Wei-Hao; Chang, Mu-Tung; Chen, Yi-Sheng; Hwu, En-Te; Hwang, Ing-Shouh

    2015-01-01

    It has been a general trend to develop low-voltage electron microscopes due to their high imaging contrast of the sample and low radiation damage. Atom-resolved transmission electron microscopes with voltages as low as 15-40 kV have been demonstrated. However, achieving atomic resolution at voltages lower than 10 kV is extremely difficult. An alternative approach is coherent imaging or phase retrieval imaging, which requires a sufficiently coherent source and an adequately small detection area on the sample as well as the detection of high-angle diffracted patterns with a sufficient resolution. In this work, we propose several transmission-type schemes to achieve coherent imaging of thin materials (less than 5 nm thick) with atomic resolution at voltages lower than 10 kV. Experimental schemes of both lens-less and lens-containing designs are presented and the advantages and challenges of these schemes are discussed. Preliminary results based on a highly coherent single-atom electron source are presented. The ...

  13. Backscatter and attenuation characterization of ventricular myocardium

    Science.gov (United States)

    Gibson, Allyson Ann

    2009-12-01

    This Dissertation presents quantitative ultrasonic measurements of the myocardium in fetal hearts and adult human hearts with the goal of studying the physics of sound waves incident upon anisotropic and inhomogeneous materials. Ultrasound has been used as a clinical tool to assess heart structure and function for several decades. The clinical usefulness of this noninvasive approach has grown with our understanding of the physical mechanisms underlying the interaction of ultrasonic waves with the myocardium. In this Dissertation, integrated backscatter and attenuation analyses were performed on midgestational fetal hearts to assess potential differences in the left and right ventricular myocardium. The hearts were interrogated using a 50 MHz transducer that enabled finer spatial resolution than could be achieved at more typical clinical frequencies. Ultrasonic data analyses demonstrated different patterns and relative levels of backscatter and attenuation from the myocardium of the left ventricle and the right ventricle. Ultrasonic data of adult human hearts were acquired with a clinical imaging system and quantified by their magnitude and time delay of cyclic variation of myocardial backscatter. The results were analyzing using Bayes Classification and ROC analysis to quantify potential advantages of using a combination of two features of cyclic variation of myocardial backscatter over using only one or the other feature to distinguish between groups of subjects. When the subjects were classified based on hemoglobin A1c, the homeostasis model assessment of insulin resistance, and the ratio of triglyceride to high-density lipoprotein-cholesterol, differences in the magnitude and normalized time delay of cyclic variation of myocardial backscatter were observed. The cyclic variation results also suggested a trend toward a larger area under the ROC curve when information from magnitude and time delay of cyclic variation is combined using Bayes classification than when

  14. An image correlation procedure for digitally reconstructed radiographs and electronic portal images

    International Nuclear Information System (INIS)

    Purpose: To study a procedure that uses megavoltage digitally reconstructed radiographs (DRRs) calculated from patient's three-dimensional (3D) computed tomography (CT) data as a reference image for correlation with on-line electronic portal images (EPIs) to detect patient setup errors. Methods and Materials: Megavoltage DRRs were generated by ray tracing through a modified volumetric CT data set in which CT numbers were converted into linear attenuation coefficients for the therapeutic beam energy. The DRR transmission image was transformed to the grayscale window of the EPI by a histogram-matching technique. An alternative approach was to calibrate the transmission DRR using a measured response curve of the electronic portal imaging device (EPID). This forces the calculated transmission fluence values to be distributed in the same range as that of the EPID image. A cross-correlation technique was used to determine the degree of alignment of the patient anatomy found in the EPID image relative to the reference DRR. Results: Phantom studies demonstrated that the correlation procedure had a standard deviation of 0.5 mm and 0.5 deg. in aligning translational shifts and in-plane rotations. Systematic errors were found between a reference DRR and a reference EPID image. The automated grayscale image-correlation process was completed within 3 s on a workstation computer or 12 s on a PC. Conclusion: The alignment procedure allows the direct comparison of a patient's treatment portal designed with a 3D planning computer with a patient's on-line portal image acquired at the treatment unit. The image registration process is automated to the extent that it requires minimal user intervention, and it is fast and accurate enough for on-line clinical applications

  15. A High-Efficiency Electron Momentum Spectrometer for Direct Imaging of Orbital Electron Density

    Institute of Scientific and Technical Information of China (English)

    REN Xue-Guang; NING Chuan-Gang; DENG Jing-Kang; ZHANG Shu-Feng; SU Guo-Lin; LI Bin; CHEN Xue-Jun

    2005-01-01

    @@ Direct three-dimensional images for orbital electron density are obtained by using our newly developed electron momentum spectrometer with simultaneous detection in energy and momentum, and the instruments resolutions of Aθ = ±0.7°, △φ = ±1.9°, △E = 1.2 eV, and △T = 2.0ns. The detection efficiency is about 100 times higher than conventional spectrometers. The design and performance of the apparatus are reported together with the experimental results on argon to show the extensive improvements in experimental resolutions, detection efficiency and versatility.

  16. Suppression of COTR in electron beam imaging diagnosis at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Minjie

    2012-05-15

    The Free-Electron Laser in Hamburg (FLASH) demands electron beams with high peak current to generate high-brilliant, coherent X-ray pulses. Magnetic chicanes are used for longitudinal compression of the electron bunches to achieve the required high peak current. During bunch compression process, microstructures with a modulation length comparable to the visible light can be induced inside the bunch. This leads to coherent emission of optical transition radiation (OTR), which may impede the widely used beam diagnostic based on OTR imaging. In this thesis, two methods of using incoherent scintillation light are proposed to circumvent the problem of coherence effects in beam imaging diagnostics. The method of temporal separation has been proved experimentally to have successfully suppressed coherence effects. The longitudinal beam profiles measured using this method are in good agreement with reference measurements, verifying further the reliability of the method. The method of spatial separation has been investigated in preparation studies, from which an improved experimental setup has been designed.

  17. Alternative optical concept for electron cyclotron emission imaging

    Energy Technology Data Exchange (ETDEWEB)

    Liu, J. X., E-mail: jsliu9@berkeley.edu [Department of Physics, University of California Berkeley, Berkeley, California 94720 (United States); Milbourne, T. [Department of Physics, College of William and Mary, Williamsburg, Virginia 23185 (United States); Bitter, M.; Delgado-Aparicio, L.; Dominguez, A.; Efthimion, P. C.; Hill, K. W.; Kramer, G. J.; Kung, C.; Pablant, N. A.; Tobias, B. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Kubota, S. [Department of Physics, University of California Los Angeles, Los Angeles, California 90095 (United States); Kasparek, W. [Department of Electrical Engineering, University of Stuttgart, Stuttgart (Germany); Lu, J. [Department of Physics, Chongqing University, Chongqing 400044 (China); Park, H. [Ulsan National Institute of Science and Technology, Ulsan 689-798 (Korea, Republic of)

    2014-11-15

    The implementation of advanced electron cyclotron emission imaging (ECEI) systems on tokamak experiments has revolutionized the diagnosis of magnetohydrodynamic (MHD) activities and improved our understanding of instabilities, which lead to disruptions. It is therefore desirable to have an ECEI system on the ITER tokamak. However, the large size of optical components in presently used ECEI systems have, up to now, precluded the implementation of an ECEI system on ITER. This paper describes a new optical ECEI concept that employs a single spherical mirror as the only optical component and exploits the astigmatism of such a mirror to produce an image with one-dimensional spatial resolution on the detector. Since this alternative approach would only require a thin slit as the viewing port to the plasma, it would make the implementation of an ECEI system on ITER feasible. The results obtained from proof-of-principle experiments with a 125 GHz microwave system are presented.

  18. Low-kilovolt coherent electron diffractive imaging instrument based on a single-atom electron source

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chun-Yueh [Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Chang, Wei-Tse; Chen, Yi-Sheng; Hwu, En-Te; Chang, Chia-Seng; Hwang, Ing-Shouh, E-mail: ishwang@phys.sinica.edu.tw [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China); Hsu, Wei-Hao [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2016-03-15

    In this work, a transmission-type, low-kilovolt coherent electron diffractive imaging instrument was constructed. It comprised a single-atom field emitter, a triple-element electrostatic lens, a sample holder, and a retractable delay line detector to record the diffraction patterns at different positions behind the sample. It was designed to image materials thinner than 3 nm. The authors analyzed the asymmetric triple-element electrostatic lens for focusing the electron beams and achieved a focused beam spot of 87 nm on the sample plane at the electron energy of 2 kV. High-angle coherent diffraction patterns of a suspended graphene sample corresponding to (0.62 Å){sup −1} were recorded. This work demonstrated the potential of coherent diffractive imaging of thin two-dimensional materials, biological molecules, and nano-objects at a voltage between 1 and 10 kV. The ultimate goal of this instrument is to achieve atomic resolution of these materials with high contrast and little radiation damage.

  19. Application of FPGA's in Flexible Analogue Electronic Image Generator Design

    Directory of Open Access Journals (Sweden)

    Peter Kulla

    2006-01-01

    Full Text Available This paper focuses on usage of the FPGAs (Field Programmable Gate Arrays Xilinx as a part of our more complex workdedicated to design of flexible analogue electronic images generator for application in TV measurement technique or/and TV servicetechnique or/and education process. The FPGAs performs here the role of component colour R, G, B, synchronization and blanking signals source. These signals are next processed and amplified in other parts of the generator as NTSC/PAL source encoder and RF modulator. The main aim of this paper is to show the possibilities how with suitable development software use a FPGAs in analog TV technology.

  20. Electronic image stabilization system based on global feature tracking

    Institute of Scientific and Technical Information of China (English)

    Zhu Juanjuan; Guo Baolong

    2008-01-01

    A new robust electronic image stabilization system is presented, which involves feature-point, tracking based global motion estimation and Kalman filtering based motion compensation. First, global motion is estimated from the local motions of selected feature points. Considering the local moving objects or the inevitable mismatch,the matching validation, based on the stable relative distance between the points set is proposed, thus maintaining high accuracy and robustness. Next, the global motion parameters are accumulated for correction by Kalman filter-ation. The experimental result illustrates that the proposed system is effective to stabilize translational, rotational,and zooming jitter and robust to local motions.

  1. Laser induced - tunneling, electron diffraction and molecular orbital imaging

    International Nuclear Information System (INIS)

    Full text: Multiphoton ionization in the tunneling limit is similar to tunneling in a scanning tunneling microscope. In both cases an electron wave packet tunnels from a bound (or valence) state to the continuum. I will show that multiphoton ionization provides a route to extend tunneling spectroscopy to the interior of transparent solids. Rotating the laser polarization is the analogue of scanning the STM tip - a means of measuring the crystal symmetry of a solid. In gas phase molecules the momentum spectrum of individual electrons can be measured. I will show that, as we rotate the molecule with respect to the laser polarization, the photoelectron spectrum samples a filter projection of the momentum wave function (the molecular analogue to the band structure) of the ionizing orbital. Some electrons created during multiphoton ionization re-collide with their parent ion. I will show that they diffract, revealing the scattering potential of the ion - the molecular structure. The electron can also interfere with the initial orbital from which it separated, creating attosecond XUV pulses or pulse trains. The amplitude and phase of the radiation contains all information needed to re-construct the image of the orbital (just as a sheared optical interferometer can fully characterize an optical pulse). Strong field methods provide an extensive range of new tools to apply to atomic, molecular and solid-state problems. (author)

  2. Infrared imaging diagnostics for intense pulsed electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiao; Shen, Jie; Liu, Wenbin; Zhong, Haowen; Zhang, Jie; Zhang, Gaolong; Le, Xiaoyun, E-mail: xyle@buaa.edu.cn [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); International Research Center for Nuclei and Particles in the Cosmos, Beihang University, Beijing 100191 (China); Qu, Miao; Yan, Sha [Institute of Heavy Ion Physics, Peking University, Beijing 100871 (China)

    2015-08-15

    Infrared imaging diagnostic method for two-dimensional calorimetric diagnostics has been developed for intense pulsed electron beam (IPEB). By using a 100-μm-thick tungsten film as the infrared heat sink for IPEB, the emitting uniformity of the electron source can be analyzed to evaluate the efficiency and stability of the diode system. Two-dimensional axisymmetric finite element method heat transfer simulation, combined with Monte Carlo calculation, was performed for error estimation and optimization of the method. The test of the method was finished with IPEB generated by explosive emission electron diode with pulse duration (FWHM) of 80 ns, electron energy up to 450 keV, and a total beam current of over 1 kA. The results showed that it is possible to measure the cross-sectional energy density distribution of IPEB with energy sensitivity of 0.1 J/cm{sup 2} and spatial resolution of 1 mm. The technical details, such as irradiation protection of bremsstrahlung γ photons and the functional extensibility of the method were discussed in this work.

  3. Electron cyclotron emission imaging and applications in magnetic fusion energy

    Science.gov (United States)

    Tobias, Benjamin John

    Energy production through the burning of fossil fuels is an unsustainable practice. Exponentially increasing energy consumption and dwindling natural resources ensure that coal and gas fueled power plants will someday be a thing of the past. However, even before fuel reserves are depleted, our planet may well succumb to disastrous side effects, namely the build up of carbon emissions in the environment triggering world-wide climate change and the countless industrial spills of pollutants that continue to this day. Many alternatives are currently being developed, but none has so much promise as fusion nuclear energy, the energy of the sun. The confinement of hot plasma at temperatures in excess of 100 million Kelvin by a carefully arranged magnetic field for the realization of a self-sustaining fusion power plant requires new technologies and improved understanding of fundamental physical phenomena. Imaging of electron cyclotron radiation lends insight into the spatial and temporal behavior of electron temperature fluctuations and instabilities, providing a powerful diagnostic for investigations into basic plasma physics and nuclear fusion reactor operation. This dissertation presents the design and implementation of a new generation of Electron Cyclotron Emission Imaging (ECEI) diagnostics on toroidal magnetic fusion confinement devices, or tokamaks, around the world. The underlying physics of cyclotron radiation in fusion plasmas is reviewed, and a thorough discussion of millimeter wave imaging techniques and heterodyne radiometry in ECEI follows. The imaging of turbulence and fluid flows has evolved over half a millennium since Leonardo da Vinci's first sketches of cascading water, and applications for ECEI in fusion research are broad ranging. Two areas of physical investigation are discussed in this dissertation: the identification of poloidal shearing in Alfven eigenmode structures predicted by hybrid gyrofluid-magnetohydrodynamic (gyrofluid-MHD) modeling, and

  4. Compton backscattered and primary X-rays from solar flares: angle dependent Green's function correction for photospheric albedo

    CERN Document Server

    Kontar, E P; Schwartz, R A; Brown, J C; Kontar, Eduard P.; Kinnon, Alec L. Mac; Schwartz, Richard A.; Brown, John C.

    2006-01-01

    The observed hard X-ray (HXR) flux spectrum $I(\\epsilon)$ from solar flares is a combination of primary bremsstrahlung photons $I_P(\\epsilon)$ with a spectrally modified component from photospheric Compton backscatter of downward primary emission. The latter can be significant, distorting or hiding the true features of the primary spectrum which are key diagnostics for acceleration and propagation of high energy electrons and of their energy budget. For the first time in solar physics, we use a Green's function approach to the backscatter spectral deconvolution problem, constructing a Green's matrix including photoelectric absorption. This approach allows spectrum-independent extraction of the primary spectrum for several HXR flares observed by the {\\it Ramaty High Energy Solar Spectroscopic Imager} (RHESSI). We show that the observed and primary spectra differ very substantially for flares with hard spectra close to the disk centre. We show in particular that the energy dependent photon spectral index $\\gamm...

  5. NOAA TIFF Image - 8m Backscatter Mosaic, Puerto Rico 2013, Vieques, Seafloor Characterization of the US Caribbean - Nancy Foster - NF-13-2 USVI (2013), UTM 20N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This geotiff represents an 8 meter resolution backscatter mosaic of a reef shelf/bank south of Vieques, Puerto Rico. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  6. 4-m Image of the Northern Half of the Pseudo-colored Backscatter Intensity of the Sea Floor off Northeastern Cape Cod (CAPENORTHPSEUDO_GEO4M_WGS84.TIF, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes pseudo-colored backscatter intensity of the sea floor offshore of northeastern Cape Cod, Massachusetts. The data were collected with a...

  7. NOAA TIFF Image - Backscatter - Lang Bank, St. Croix, USVI - Benthic Habitat Characterization - NOAA Ship Nancy Foster - M-1907-NF-14 (2014), UTM 20N NAD83 (NCEI Accession 0128255)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This geotiff represents a 1 meter resolution backscatter mosaic of the reef shelf and the steep slopes of the Lang Bank (H12639) of St. Croix, US Virgin Islands....

  8. 4-m Image of the Northern Half of the Backscatter Intensity Mosaic of the Sea Floor off Northeastern Cape Cod from USGS Cruise 98015 (CAPENORTHMOS_GEO4M_WGS84.TIF, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes backscatter intensity of the sea floor offshore of northern Cape Cod, Massachusetts. The data were collected with a multibeam sea floor...

  9. 4-m Image of the Southern Half of the Pseudo-colored Backscatter Intensity of the Sea Floor off Eastern Cape Cod (CAPESOUTHPSEUDO_GEO4M_WGS84.TIF, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes pseudo-colored backscatter intensity of the sea floor offshore of northeastern Cape Cod, Massachusetts. The data were collected with a...

  10. 4-m Image of the Southern Half of the Backscatter Intensity Mosaic of the Sea Floor off Eastern Cape Cod from USGS Cruise 98015 (CAPESOUTHMOS_GEO4M_WGS84.TIF, Geographic, WGS84)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set includes backscatter intensity of the sea floor offshore of eastern Cape Cod, Massachusetts. The data were collected with a multibeam sea floor...

  11. NOAA TIFF Image - 3x3m Multibeam Backscatter, US Virgin Islands - Vieques Island (South Bank) - Project NF-09-01 - (2009), UTM 20N NAD83 (NCEI Accession 0131857)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a GeoTIFF with 3x3 meter cell size representing the backscatter or intensity of sound returned from the seafloor on the bank/shelf escarpment...

  12. The dose from Compton backscatter screening.

    Science.gov (United States)

    Rez, Peter; Metzger, Robert L; Mossman, Kenneth L

    2011-04-01

    Systems based on the detection of Compton backscattered X rays have been deployed for screening personnel for weapons and explosives. Similar principles are used for screening vehicles at border-crossing points. Based on well-established scattering cross sections and absorption coefficients in conjunction with reasonable estimates of the image contrast and resolution, the entrance skin dose and the dose at a depth of 1 cm can be calculated. The effective dose can be estimated using the same conversion coefficients as used to convert exposure measurements to the effective dose. It is shown that the effective dose is highly dependent on image resolution (i.e. pixel size).The effective doses for personnel screening systems are unlikely to be in compliance with the American National Standards Institute standard NS 43.17 unless the pixel sizes are >4 mm. Nevertheless, calculated effective doses are well below doses associated with health effects. PMID:21068018

  13. An observer study for direct comparison of clinical efficacy of electronic to film portal images

    International Nuclear Information System (INIS)

    Purpose: To directly compare clinical efficacy of electronic to film portal images. Methods and Materials: An observer study was designed to compare clinical efficacy of electronic to film portal images acquired using a liquid matrix ion-chamber electronic portal imaging device and a conventional metal screen/film system. Both images were acquired simultaneously for each treatment port and the electronic portal images were printed on gray-level thermal paper. Four radiation oncologists served as observers and evaluated a total of 44 sets of images for four different treatment sites: lung, pelvis, brain, and head/neck. Each set of images included a simulation image, a double-exposure portal film, and video paper prints of electronic portal images. Eight to nine anatomical landmarks were selected from each treatment site. Each observer was asked to rate each landmark in terms of its clinical visibility and to rate the ease of making the pertinent verification decision in the corresponding electronic and film portal images with the aid of the simulation image. Results: Ratings for the visibility of landmarks and for the verification decision of treatment ports were similar for electronic and film images for most landmarks. However, vertebral bodies and several landmarks in the pelvis such as the acetabulum and pubic symphysis were more visible in the portal film images than in the electronic portal images. Conclusion: The visibility of landmarks in electronic portal images is comparable to that in film portal images. Verification of treatment ports based only on electronic portal images acquired using an electronic portal imaging device is generally achievable

  14. Probing Molecular Dynamics by Laser-Induced Backscattering Holography

    Science.gov (United States)

    Haertelt, Marko; Bian, Xue-Bin; Spanner, Michael; Staudte, André; Corkum, Paul B.

    2016-04-01

    We use differential holography to overcome the forward scattering problem in strong-field photoelectron holography. Our differential holograms of H2 and D2 molecules exhibit a fishbonelike structure, which arises from the backscattered part of the recolliding photoelectron wave packet. We demonstrate that the backscattering hologram can resolve the different nuclear dynamics between H2 and D2 with subangstrom spatial and subcycle temporal resolution. In addition, we show that attosecond electron dynamics can be resolved. These results open a new avenue for ultrafast studies of molecular dynamics in small molecules.

  15. Dosimetric properties of the Theraview fluoroscopic electronic portal imaging device.

    Science.gov (United States)

    Glendinning, A G; Bonnett, D E

    2000-05-01

    Electronic portal imaging devices (EPIDs) can be used for non-imaging applications in radiotherapy such as patient dosimetry. Of the systems available, the fluoroscopic camera-based EPID Theraview (InfiMed Inc.) has not been studied to date, and a review of the dosimetric properties of the system is presented here. In the "single set-up" mode of image acquisition, pixel intensity increases sublinearly with applied dose. The response was dependent on the system's video signal gain and showed a threshold dose to the detector in the range 0.05-0.35 cGy, and pixel saturation at detector doses in the range 1.2-1.6 cGy. Repeated exposures of the EPID were observed to be extremely reproducible (standard deviation 0.5%). The sensitivity of the system showed a linear decline of 0.04% day-1 over a 68-day period, during which time the relative off-axis response within 10 x 10 cm2 field was constant to within a standard deviation of 0.56%. The system shows spatial non-uniformity, which requires correction for application to dose measurements in two-dimensions. Warm-up of the camera control unit required a period of at least 40 min and was associated with an enhancement in pixel intensity of up to 12%. A radiation dose history effect was observed at doses as low as 0.2 Gy. Camera dark current was shown to be negligible at normal accelerator operation. No discernible image distortion was found. Mechanical stability on gantry rotation was also assessed and image displacement of up to 5 mm at the isocentre was observed. It was concluded that the device could be used for dosimetry provided necessary precautions were observed and corrections made. PMID:10884749

  16. BackscatterA [8101]--Offshore Pacifica, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pacifica map area, California. Backscatter data are provided as two separate grids...

  17. Backscatter C [7125]--Offshore Bolinas, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bolinas map area, California. Backscatter data are provided as separate grids...

  18. Backscatter B [8101]--Offshore Bolinas, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bolinas map area, California. Backscatter data are provided as separate grids...

  19. BackscatterB [7125]--Offshore Pacifica, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pacifica map area, California. Backscatter data are provided as two separate grids...

  20. Backscatter [SWATH]--Offshore Santa Cruz, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Santa Cruz map area, California. Backscatter data are provided as three separate...

  1. Backscatter A [8101]--Offshore Bolinas, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bolinas map area, California. Backscatter data are provided as separate grids...

  2. Backscatter E [Swath]--Offshore Bolinas, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bolinas map area, California. Backscatter data are provided as separate grids...

  3. Backscatter D [Snippets]--Offshore Bolinas, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bolinas map area, California. Backscatter data are provided as separate grids...

  4. Backscatter [5m]--Offshore Monterey, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Monterey map area, California. Backscatter data are provided as separate grids...

  5. Nodule bottom backscattering study using multibeam echosounder

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Raju, Y.S.N.; Nair, R.R.

    A study is carried out to observe the angular dependence of backscattering strength at nodule area where grab sample and photographic data is available. Theoretical study along with the experimentally observed data shows that the backscattering...

  6. Backscatter A [8101]--Offshore San Gregorio, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3306 presents data for the acoustic-backscatter map (see sheet 3, SIM 3306) of the Offshore of San Gregorio map area, California. Backscatter data...

  7. Backscatter B [7125]--Offshore San Gregorio, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3306 presents data for the acoustic-backscatter map (see sheet 3, SIM 3306) of the Offshore of San Gregorio map area, California. Backscatter data...

  8. Ion Momentum Imaging of Dissociative Electron Attachment to Small Molecules

    Science.gov (United States)

    Fogle, Michael

    2015-09-01

    In recent years, low energy dissociative electron attachment (DEA) interactions have been of interest to varying biological and technological applications. To study the dynamics resulting from DEA, we used an ion-momentum imaging apparatus based on the Cold Target Recoil Ion Momentum Spectroscopy (COLTRIMS) technique in which a molecular beam is crossed by a pulsed electron beam. The beam interaction takes place in a 4 π pulsed electrostatic spectrometer that collects the anion fragments resulting from DEA. The molecular beam is formed by a supersonic expansion which results in a well-localized and cold target. Using this apparatus we have investigated the DEA dynamics for several small molecules: CO2 at the 4 eV shape resonance and the 8 eV Feshbach resonance; N2O at the 2.3 eV shape resonance; HCCH at the 3 eV shape resonance; and CF4 near the 7 eV resonance. An overview of these experimental ion-momentum results will be compared to ab initio electronic structure and fixed-nuclei scattering calculations to gauge the resulting dynamics driven by DEA. In many cases, conical intersections play a pivotal role in driving the dynamics. Some of these systems exhibit non-axial recoil conditions indicative of a bending dynamics in the transitory negative ion state while others exhibit a direct axial recoil dissociation without any bending. This work is supported by the National Science Foundation under Contract NSF-PHYS1404366.

  9. Clinical task performance and imaging task performance compared for two different commercial electronic portal imaging systems

    International Nuclear Information System (INIS)

    Full text: This paper reports on the investigation and comparison of performance of a Varian Portal Vision system and a Siemens Beamview Plus system using the framework outlined by ICRU Report 54. Radiation Therapy EPI (Electronic Portal Imaging) systems are one of the main applications of digital imaging technology in a radiation therapy department. Radiation Therapy EPI systems may produce images of a lesser quality than the diagnostic radiology equivalent. It is therefore important to optimise the system to obtain the best performance possible. Contrasting opinion on the performance of EPI by clinicians, radiation therapists, medical physicists and engineers often exists, even when the same system and even the same image are being evaluated. Differing opinion occurs because of differences in task end points and task assessment methods of two broad groups of individuals, the human-observer group and the technical-measurement group. Each group uses different task criteria and methodology for assessing performance. The human-observer group is primarily interested in system performance that assures a high level clinical-task performance while the technical-measurement group is concerned with system performance that assures a high level of imaging-task performance. The technical-measurement group tends to be closely associated with imaging system technology, testing, adjustment and optimisation tasks which are couched in terms imaging-task criteria. The human-observer group is usually attempting to optimise performance using clinical-task criteria. The challenge is to provide a balanced evaluation using complementary imaging-task performance and clinical-task performance assessments. Comparison of the systems is on the basis of imaging-task performance i.e. technical-measurement through physical performance assessments such as spatial resolution and noise level, and clinical-task performance i.e. human-observer measurements through the application of psychophysical

  10. Serial section scanning electron microscopy (S3EM on silicon wafers for ultra-structural volume imaging of cells and tissues.

    Directory of Open Access Journals (Sweden)

    Heinz Horstmann

    Full Text Available High resolution, three-dimensional (3D representations of cellular ultrastructure are essential for structure function studies in all areas of cell biology. While limited subcellular volumes have been routinely examined using serial section transmission electron microscopy (ssTEM, complete ultrastructural reconstructions of large volumes, entire cells or even tissue are difficult to achieve using ssTEM. Here, we introduce a novel approach combining serial sectioning of tissue with scanning electron microscopy (SEM using a conductive silicon wafer as a support. Ribbons containing hundreds of 35 nm thick sections can be generated and imaged on the wafer at a lateral pixel resolution of 3.7 nm by recording the backscattered electrons with the in-lens detector of the SEM. The resulting electron micrographs are qualitatively comparable to those obtained by conventional TEM. S(3EM images of the same region of interest in consecutive sections can be used for 3D reconstructions of large structures. We demonstrate the potential of this approach by reconstructing a 31.7 µm(3 volume of a calyx of Held presynaptic terminal. The approach introduced here, Serial Section SEM (S(3EM, for the first time provides the possibility to obtain 3D ultrastructure of large volumes with high resolution and to selectively and repetitively home in on structures of interest. S(3EM accelerates process duration, is amenable to full automation and can be implemented with standard instrumentation.

  11. ILC Beam Energy Measurement by means of Laser Compton Backscattering

    OpenAIRE

    Muchnoi, N.; Schreiber, H. J.; Viti, M

    2008-01-01

    A novel, non-invasive method of measuring the beam energy at the International Linear Collider is proposed. Laser light collides head-on with beam particles and either the energy of the Compton scattered electrons near the kinematic end-point is measured or the positions of the Compton backscattered $\\gamma$-rays, the edge electrons and the unscattered beam particles are recorded. A compact layout for the Compton spectrometer is suggested. It consists of a bending magnet and position sensitiv...

  12. NOAA TIFF Graphic- 0.5m Backscatter Mosaic of St. Thomas, US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the south shore of St. Thomas, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography Team and...

  13. Backscatter 0.5m TIFF Mosaic of St. Croix (Buck Island), US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the north shore of Buck Island, St. Croix, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography...

  14. Backscatter 0.5m TIFF Mosaic of St. Thomas, US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the south shore of St. Thomas, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team and...

  15. Combining angular response classification and backscatter imagery segmentation for benthic biological habitat mapping

    Science.gov (United States)

    Che Hasan, Rozaimi; Ierodiaconou, Daniel; Laurenson, Laurie

    2012-01-01

    Backscatter information from multibeam echosounders (MBES) have been shown to contain useful information for the characterisation of benthic habitats. Compared to backscatter imagery, angular response of backscatter has shown advantages for feature discrimination. However its low spatial resolution inhibits the generation of fine scale habitat maps. In this study, angular backscatter response was combined with image segmentation of backscatter imagery to characterise benthic biological habitats in Discovery Bay Marine National Park, Victoria, Australia. Angular response of backscatter data from a Reson Seabat 8101 MBES (240 kHz) was integrated with georeferenced underwater video observations for constructing training data. To produce benthic habitat maps, decision tree supervised classification results were combined with mean shift image segmentation for class assignment. The results from mean angular response characteristics show effects of incidence angle at the outer angle for invertebrates (INV) and mixed red and invertebrates (MRI) classes, whilst mixed brown algae (MB) and mixed brown algae and invertebrates (MBI) showed similar responses independent from incidence angle. Automatic segmentation processing produce over segmented results but showed good discrimination between heterogeneous regions. Accuracy assessment from habitat maps produced overall accuracies of 79.6% (Kappa coefficient = 0.66) and 80.2% (Kappa coefficient = 0.67) for biota and substratum classifications respectively. MRI and MBI produced the lowest average accuracy while INV the highest. The ability to combine angular response and backscatter imagery provides an alternative approach for investigating biological information from acoustic backscatter data.

  16. Improvements in backscatter measurement devices

    International Nuclear Information System (INIS)

    Improvements in measuring the thickness of a coating on a substrate by the technique of backscattered particles are described. These improvements enable the measurements to be carried out continuously as an integral part of the coating production line and also permit measurements where the coated elements are separated from one another by a predetermined distance. The former is achieved by situating the backscatter probe and detector on the rim of the measurement wheel and rotating this wheel at a speed such that the coated element and probe are stationary relative to one another. The latter improvement is achieved by an indexing apparatus which automatically positions the probe beside a coated element. (U.K.)

  17. A Micropulse eye-safe all-fiber molecular backscatter coherent temperature lidar

    Science.gov (United States)

    Abari, Cyrus F.; Chu, Xinzhao; Mann, Jakob; Spuler, Scott

    2016-06-01

    In this paper, we analyze the performance of an all-fiber, micropulse, 1.5 μm coherent lidar for remote sensing of atmospheric temperature. The proposed system benefits from the recent advances in optics/electronics technology, especially an all-fiber image-reject homodyne receiver, where a high resolution spectrum in the baseband can be acquired. Due to the presence of a structured spectra resulting from the spontaneous Rayleigh-Brillouine scattering, associated with the relevant operating regimes, an accurate estimation of the temperature can be carried out. One of the main advantages of this system is the removal of the contaminating Mie backscatter signal by electronic filters at the baseband (before signal conditioning and amplification). The paper presents the basic concepts as well as a Monte-Carlo system simulation as the proof of concept.

  18. A Micropulse eye-safe all-fiber molecular backscatter coherent temperature lidar

    Directory of Open Access Journals (Sweden)

    Abari Cyrus F.

    2016-01-01

    Full Text Available In this paper, we analyze the performance of an all-fiber, micropulse, 1.5 μm coherent lidar for remote sensing of atmospheric temperature. The proposed system benefits from the recent advances in optics/electronics technology, especially an all-fiber image-reject homodyne receiver, where a high resolution spectrum in the baseband can be acquired. Due to the presence of a structured spectra resulting from the spontaneous Rayleigh-Brillouine scattering, associated with the relevant operating regimes, an accurate estimation of the temperature can be carried out. One of the main advantages of this system is the removal of the contaminating Mie backscatter signal by electronic filters at the baseband (before signal conditioning and amplification. The paper presents the basic concepts as well as a Monte-Carlo system simulation as the proof of concept.

  19. Current profile reconstruction using electron temperature imaging diagnostics

    Science.gov (United States)

    Tritz, K.; Stutman, D.; Delgado-Aparicio, L. F.; Finkenthal, M.; Pacella, D.; Kaita, R.; Stratton, B.; Sabbagh, S.

    2004-10-01

    Flux surface shape information can be used to constrain the current profile for reconstruction of the plasma equilibrium. One method of inferring flux surface shape relies on plasma x-ray emission; however, deviations from the flux surfaces due to impurity and density asymmetries complicate the interpretation. Electron isotherm surfaces should correspond well to the plasma flux surfaces, and equilibrium constraint modeling using this isotherm information constrains the current profile. The KFIT code is used to assess the profile uncertainty and to optimize the number, location and SNR required for the Te detectors. As Te imaging detectors we consider tangentially viewing, vertically spaced, linear gas electron multiplier arrays operated in pulse height analysis (PHA) mode and multifoil soft x-ray arrays. Isoflux coordinate sets provided by Te measurements offer a strong constraint on the equilibrium reconstruction in both a stacked horizontal array configuration and a crossed horizontal and vertical beam system, with q0 determined to within ±4%. The required SNR can be provided with either PHA or multicolor diagnostic techniques, though the multicolor system requires ˜×4 better statistics for comparable final errors.

  20. ILC Beam Energy Measurement by means of Laser Compton Backscattering

    CERN Document Server

    Muchnoi, N; Viti, M

    2008-01-01

    A novel, non-invasive method of measuring the beam energy at the International Linear Collider is proposed. Laser light collides head-on with beam particles and either the energy of the Compton scattered electrons near the kinematic end-point is measured or the positions of the Compton backscattered $\\gamma$-rays, the edge electrons and the unscattered beam particles are recorded. A compact layout for the Compton spectrometer is suggested. It consists of a bending magnet and position sensitive detectors operating in a large radiation environment. Several options for high spatial resolution detectors are discussed. Simulation studies support the use of an infrared or green laser and quartz fiber detectors to monitor the backscattered photons and edge electrons. Employing a cavity monitor, the beam particle position downstream of the magnet can be recorded with submicrometer precision. Such a scheme provides a feasible and promising method to access the incident beam energy with precisions of $10^{-4}$ or bette...

  1. Characteristics of final particles in multiple Compton backscattering process

    Science.gov (United States)

    Potylitsyn, A.; Kol‘chuzhkin, A.

    2013-08-01

    An electron passing through a counter propagating intense laser beam can interact with a few laser photons with emission of a hard photon in each collision event. In contrast with the well-known nonlinear Compton backscattering process the above mentioned process may be named as multiple Compton backscattering process (MCBS). In this paper we have investigated the evolution of the electron energy distribution during MCBS process using Monte-Carlo (M-C) simulation. The main characteristics of such a distribution as mean energy and variance obtained by M-C technique were compared with analytical solutions of kinetic equations. We found the kinematic region where the analytical solutions are applicable with a good accuracy. A photon spectrum, even for the case when each electron emits one photon (in average) differs significantly from that described by the Klein-Nishina formula.

  2. Characteristics of Final Particles in Multiple Compton Backscattering Process

    CERN Document Server

    Potylitsyn, A

    2013-01-01

    An electron passing through a counter propagating intense laser beam can interact with a few laser photons with emission of a hard photon in each collision event. In contrast with the well-known nonlinear Compton backscattering process the above mentioned process may be named as multiple Compton backscattering process (MCBS). In this paper we have investigated the evolution of the electron energy distribution during MCBS process using Monte-Carlo (M-C) simulation. The main characteristics of such a distribution as mean energy and variance obtained by M-C technique were compared with analytical solutions of kinetic equations. We found the kinematic region where the analytical solutions are applicable with a good accuracy. A photon spectrum, even for the case when each electron emits one photon (in average) differs significantly from that described by the Klein-Nishina formula.

  3. Electronic intraoral dental x-ray imaging system employing a direct sensing CCD array

    International Nuclear Information System (INIS)

    A commercial prototype intraoral radiography system has been developed that can provide digital x-ray images for diagnosis. The system consists of an intraoral detector head, an intermediate drive electronics package, a main drive electronics package and a PC-based digital image management system. The system has the potential to replace the use of dental film in intraoral radiographic examinations. High-resolution images are acquired, then displayed on a CRT within seconds of image acquisition

  4. Electronic intraoral dental x-ray imaging system employing a direct-sensing CCD array

    Science.gov (United States)

    Cox, John D.; Langford, D. S.; Williams, Donald W.

    1993-12-01

    A commercial prototype intraoral radiography system has been developed that can provide digital x-ray images for diagnosis. The system consists of an intraoral detector head, an intermediate drive electronics package, a main drive electronics package, and a PC-based digital image management system. The system has the potential to replace the use of dental film in intraoral radiographic examinations. High-resolution images are acquired, then displayed on a CRT within seconds of image acquisition.

  5. Statistical simulation of multiple Compton backscattering process

    Science.gov (United States)

    Potylitsyn, A. P.; Kolchuzhkin, A. M.

    2014-09-01

    A number of laboratories are currently developing monochromatic sources of X-rays and gamma quanta based on the Compton backscattering (CBS) of laser photons by relativistic electrons. Modern technologies are capable of providing a concentration of electrons and photons in the interaction point such that each primary electron can emit several hard photons. In contrast to the well-known nonlinear CBS process, in which an initial electron "absorbs" a few laser photons and emits a single hard one, the above-mentioned process can be called a multiple CBS process and is characterized by a mean number of emitted photons. The present paper is devoted to simulating the parameters of a beam of back scattered quanta based on the Monte Carlo technique. It is shown that, even in the case of strong collimation of a resulting photon beam, the radiation monochromaticity may deteriorate because of the contribution coming from the multiple photon emission, which is something that must be considered while designing new CBS sources.

  6. Application of Ion and Electron Momentum Imaging to Atomic Collisions

    Science.gov (United States)

    Cocke, C. L.

    2000-06-01

    COLTRIMS (COLd Target Recoil Ion Momentum Spectroscopy) combines fast imaging detectors with a supersonically cooled gas target to allow the charged particles from any ionizing collision, including both recoil ions and electrons, to be collected with extremely high efficiency and with fully measured vector momenta. Since all particles are measured in event mode, the full multi-dimensional momentum space is mapped. We will review several examples of the use of this technique to study two- , three- and four-body final states created in ionizing interactions of photons and charged particles with He and D2 . The momentum spectra of electrons ejected from these targets by slow projectiles reveal the stucture of the molecular orbitals which are promoted into the continuum. Double photoionization of the same targets reveals patterns which can be interpreted in terms of collective coordinates. Two-electron removal from D2 by Xe ^26+ reveals the influence of the projectile field on the dissociation process. A recent application of the technique to ionization by high intensity laser fields will be discussed. Work performed in collaboration with M.A.Abdallah^1, I.Ali^1, Matthias Achler^2, H.Braeuning^2,3, Angela Braeuning-Deminian^2, Achim Czasch^2,3, R.Doerner^2,3, R.DuBois^6, A. Landers^1,5, V.Mergel^2, R.E.Olson^6, T.Osipov^1, M.Prior^3, H.Schmidt-Boecking^2, M.Singh^1, A.Staudte^2,3, T.Weber^2, W.Wolff^4, and H.E.Wolf^4 ^1J.R.Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS 66506; ^2 Institut fuer Kernphysik, Univ. Frankfurt, August-Euler-Str.6,D-60486 Frankfurt, Germany ; ^3Lawrence Berkeley National Laboratory, Berkeley, CA 94720; ^4Instituto de Fisica, Universidade Federal do Rio de Janeiro Caixa Postal 68.528, 21945-970, Rio de Janeiro, Brazil; ^5Physics Dept., Western Michigan University, Kalamazoo, MI 49008; ^6Physics Dept., Univ. Missouri Rolla, Rolla, MO 65409 Work supported by the Division of Chemical Sciences, Office of Basic

  7. Analysis of the IMAGE RPI electron density data and CHAMP plasmasphere electron density reconstructions with focus on plasmasphere modelling

    Science.gov (United States)

    Gerzen, T.; Feltens, J.; Jakowski, N.; Galkin, I.; Reinisch, B.; Zandbergen, R.

    2016-09-01

    The electron density of the topside ionosphere and the plasmasphere contributes essentially to the overall Total Electron Content (TEC) budget affecting Global Navigation Satellite Systems (GNSS) signals. The plasmasphere can cause half or even more of the GNSS range error budget due to ionospheric propagation errors. This paper presents a comparative study of different plasmasphere and topside ionosphere data aiming at establishing an appropriate database for plasmasphere modelling. We analyze electron density profiles along the geomagnetic field lines derived from the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) satellite/Radio Plasma Imager (RPI) records of remote plasma sounding with radio waves. We compare these RPI profiles with 2D reconstructions of the topside ionosphere and plasmasphere electron density derived from GNSS based TEC measurements onboard the Challenging Minisatellite Payload (CHAMP) satellite. Most of the coincidences between IMAGE profiles and CHAMP reconstructions are detected in the region with L-shell between 2 and 5. In general the CHAMP reconstructed electron densities are below the IMAGE profile densities, with median of the CHAMP minus IMAGE residuals around -588 cm-3. Additionally, a comparison is made with electron densities derived from passive radio wave RPI measurements onboard the IMAGE satellite. Over the available 2001-2005 period of IMAGE measurements, the considered combined data from the active and passive RPI operations cover the region within a latitude range of ±60°N, all longitudes, and an L-shell ranging from 1.2 to 15. In the coincidence regions (mainly 2 ⩽ L ⩽ 4), we check the agreement between available active and passive RPI data. The comparison shows that the measurements are well correlated, with a median residual of ∼52 cm-3. The RMS and STD values of the relative residuals are around 22% and 21% respectively. In summary, the results encourage the application of IMAGE RPI data for

  8. Scanning transmission and computer-aided volumic electron microscopy: 3-D modeling of entire cells by electronic imaging

    Science.gov (United States)

    Bron, Christophe; Gremillet, Philip; Launay, D.; Jourlin, Michel; Gautschi, H. P.; Baechi, Thomas; Schuepbach, Joerg

    1990-05-01

    The digital processing of electron microscopic images from serial sections containing laser-induced topographical references allows a 3-D reconstruction at a depth resolution of 30 to 40 nm of entire cells by the use of image analysis methods, as already demonstrated for Transmission Electron Microscopy (TEM) coupled with a video camera. We decided to use a Scanning Transmission Electron Microscope (STEM) to get higher contrast and better resolution at medium magnification. The scanning of our specimens at video frequencies is an attractive and easy way to link a STEM with an image processing system but the hysteresis of the electronic spools responsible for the magnetic deviation of the scanning electron beam induces deformations of images which have to be modelized and corrected before registration. Computer algorithms developed for image analysis and treatment correct the artifacts caused by the use of STEM and by serial sectioning to automatically reconstruct the third dimension of the cells. They permit the normalization of the images through logarithmic processing of the original grey level infonnation. The automatic extraction of cell limits allows to link the image analysis and treatments with image synthesis methods by minimal human intervention. The surface representation and the registered images provide an ultrastructural data base from which quantitative 3-D morphological parameters, as well as otherwise impossible visualizations, can be computed. This 3-D image processing named C.A.V.U.M. for Computer Aided Volumic Ultra-Microscopy offers a new tool for the documentation and analysis of cell ultrastructure and for 3-D morphometric studies at EM magnifications. Further, a virtual observer can be computed in such a way as to simulate a visit of the reconstructed object.

  9. The influence of structure depth on image blurring of micrometres-thick specimens in MeV transmission electron imaging.

    Science.gov (United States)

    Wang, Fang; Sun, Ying; Cao, Meng; Nishi, Ryuji

    2016-04-01

    This study investigates the influence of structure depth on image blurring of micrometres-thick films by experiment and simulation with a conventional transmission electron microscope (TEM). First, ultra-high-voltage electron microscope (ultra-HVEM) images of nanometer gold particles embedded in thick epoxy-resin films were acquired in the experiment and compared with simulated images. Then, variations of image blurring of gold particles at different depths were evaluated by calculating the particle diameter. The results showed that with a decrease in depth, image blurring increased. This depth-related property was more apparent for thicker specimens. Fortunately, larger particle depth involves less image blurring, even for a 10-μm-thick epoxy-resin film. The quality dependence on depth of a 3D reconstruction of particle structures in thick specimens was revealed by electron tomography. The evolution of image blurring with structure depth is determined mainly by multiple elastic scattering effects. Thick specimens of heavier materials produced more blurring due to a larger lateral spread of electrons after scattering from the structure. Nevertheless, increasing electron energy to 2MeV can reduce blurring and produce an acceptable image quality for thick specimens in the TEM.

  10. Microstructure and properties of laser clad coatings studied by orientation imaging microscopy

    NARCIS (Netherlands)

    Ocelik, V.; Furar, I.; De Hosson, J. Th. M.

    2010-01-01

    In this work orientation imaging microscopy (OIM), based on electron backscatter diffraction in scanning electron microscopy, was employed to examine in detail the relationship between laser cladding processing parameters and he properties and the microstructure of single and overlapping laser track

  11. Ultrasound Backscattering Is Anisotropic in Bovine Articular Cartilage.

    Science.gov (United States)

    Inkinen, Satu I; Liukkonen, Jukka; Tiitu, Virpi; Virén, Tuomas; Jurvelin, Jukka S; Töyräs, Juha

    2015-07-01

    Collagen, proteoglycans and chondrocytes can contribute to ultrasound scattering in articular cartilage. However, anisotropy of ultrasound scattering in cartilage is not fully characterized. We investigate this using a clinical intravascular ultrasound device with ultrasound frequencies of 9 and 40 MHz. Osteochondral samples were obtained from intact bovine patellas, and cartilage was imaged in two perpendicular directions: through articular and lateral surfaces. At both frequencies, ultrasound backscattering was higher (p < 0.05) when measured through the lateral surface of cartilage. In addition, the composition and structure of articular cartilage were investigated with multiple reference methods involving light microscopy, digital densitometry, polarized light microscopy and Fourier infrared imaging. Reference methods indicated that acoustic anisotropy of ultrasound scattering arises mainly from non-uniform distribution of chondrocytes and anisotropic orientation of collagen fibers. To conclude, ultrasound backscattering in articular cartilage was found to be anisotropic and dependent on the frequency in use. PMID:25933711

  12. Post calibration of the two-dimensional electron cyclotron emission imaging instrument with electron temperature characteristics of the magnetohydrodynamic instabilities.

    Science.gov (United States)

    Choi, M J; Park, H K; Yun, G S; Nam, Y B; Choe, G H; Lee, W; Jardin, S

    2016-01-01

    The electron cyclotron emission imaging (ECEI) instrument is widely used to study the local electron temperature (Te) fluctuations by measuring the ECE intensity IECE ∝ Te in tokamak plasmas. The ECEI measurement is often processed in a normalized fluctuation quantity against the time averaged value due to complication in absolute calibration. In this paper, the ECEI channels are relatively calibrated using the flat Te assumption of the sawtooth crash or the tearing mode island and a proper extrapolation. The 2-D relatively calibrated electron temperature (Te,rel) images are reconstructed and the displacement amplitude of the magnetohydrodynamic modes can be measured for the accurate quantitative growth analysis.

  13. Conductance and noise signatures of Majorana backscattering

    OpenAIRE

    Chung, Suk Bum; Qi, Xiao-Liang; Maciejko, Joseph; Zhang, Shou-Cheng

    2010-01-01

    We propose a conductance measurement to detect the backscattering of chiral Majorana edge states. Because normal and Andreev processes have equal probability for backscattering of a single chiral Majorana edge state, there is qualitative difference from backscattering of a chiral Dirac edge state, giving rise to half-integer Hall conductivity and decoupling of fluctuation in incoming and outgoing modes. The latter can be detected through thermal noise measurement. These experimental signature...

  14. Algorithms for contrast enhancement of electronic portal images

    Science.gov (United States)

    Díez, S.; Sánchez, S.

    2015-11-01

    An implementation of two new automatized image processing algorithms for contrast enhancement of portal images is presented as suitable tools which facilitate the setup verification and visualization of patients during radiotherapy treatments. In the first algorithm, called Automatic Segmentation and Histogram Stretching (ASHS), the portal image is automatically segmented in two sub-images delimited by the conformed treatment beam: one image consisting of the imaged patient obtained directly from the radiation treatment field, and the second one is composed of the imaged patient outside it. By segmenting the original image, a histogram stretching can be independently performed and improved in both regions. The second algorithm involves a two-step process. In the first step, a Normalization to Local Mean (NLM), an inverse restoration filter is applied by dividing pixel by pixel a portal image by its blurred version. In the second step, named Lineally Combined Local Histogram Equalization (LCLHE), the contrast of the original image is strongly improved by a Local Contrast Enhancement (LCE) algorithm, revealing the anatomical structures of patients. The output image is lineally combined with a portal image of the patient. Finally the output images of the previous algorithms (NLM and LCLHE) are lineally combined, once again, in order to obtain a contrast enhanced image. These two algorithms have been tested on several portal images with great results.

  15. Enhancing availability of the electronic image record for patients and caregivers during follow-up care

    OpenAIRE

    Mehta, Amit; Dreyer, Keith; Thrall, James

    1999-01-01

    To develop a personal computer (PC)-based software package that allows portability of the electronic imaging record. To create custom software that enhances the transfer of images in two fashions. Firstly, to an end user, whether physician or patient, provide a browser capable of viewing digital images on a conventional personal computer. Second, to provide the ability to transfer the archived Digital Imaging and Communications in Medicine (DICOM) images to other institutional picture archivi...

  16. Innovative Concepts for the Electronic Interface of Massively Parallel MRI Phased Imaging Arrays

    OpenAIRE

    Jouda, Mazin

    2016-01-01

    In Magnetic Resonance Imaging (MRI), the concept of parallel imaging shows significant enhancements in boosting the signal-to-noise ratio, reducing the imaging time, and enlarging the imaging field of view. However, this concept necessitates increased size, cost, and complexity of the MR system. This thesis introduces an innovative solution for the electronics of the MRI system that allows parallel imaging with massive number of channels while avoiding, at the same time, the associated drawbacks

  17. Evaluation of usefulness of portal image using Electronic Portal Imaging Device (EPID) in the patients who received pelvic radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Woo Chul; Kim, Heon Jong; Park, Seong Young; Cho, Young Kap; Loh, John J. K. [College of Medicine, Inha Univ., Pusan (Korea, Republic of); Park, Won; Suh, Chang Ok; Kim, Gwi Eon [College of Medicine, Yonsei Univ., Seoul (Korea, Republic of)

    1998-12-01

    To evaluate the usefulness of electronic portal imaging device through objective compare of the images acquired using an EPID and a conventional port film. From Apr. to Oct. 1997, a total of 150 sets of images from 20 patients who received radiation therapy in the pelvis area were evaluated in the Inha University Hospital and Severance Hospital. A dual image recording technique was devised to obtain both electronic portal images and port film images simultaneously with one treatment course. We did not perform double exposure. Five to ten images were acquired from each patient. All images were acquired from posteroanterior (PA) view except images from two patients. A dose rate of 100-300 MU/min and a 10-MV X-ray beam were used and 2-10 MUs were required to produce a verification image during treatment. Kodak diagnostic film with metal/film imaging cassette which was located on the top of the EPID detector was used for the port film. The source to detector distance was 140 cm. Eight anatomical landmarks (pelvic brim, sacrum, acetabulum, iliopectineal line, symphysis, ischium, obturator foramen, sacroiliac joint) were assessed. Four radiation oncologist joined to evaluate each image. The individual landmarks in the port film or in the EPID were rated-very clear (1), clear (2), visible (3), notclear (4), not visible (5). Using an video camera based EPID system, there was no difference of image quality between no enhanced EPID images and port film images. However, when we provided some change with window level for the portal image, the visibility of the sacrum and obturator foramen was improved in the portal images than in the port film images. All anatomical landmarks were more visible in the portal images than in the port film when we applied the CLAHE mode enhancement. The images acquired using an matrix ion chamber type EPID were also improved image quality after window level adjustment. The quality of image acquired using an electronic portal imaging device was

  18. An application of ultrasonic phased array imaging in electron beam welding inspection

    Institute of Scientific and Technical Information of China (English)

    周琦; 刘方军; 李志军; 李旭东; 齐铂金

    2002-01-01

    The basic principle and features of ultrasonic phased array imaging are discussed in this paper. Through the ultrasonic phased array technology, the electron beam welding defects and frozen keyholes characterization and imaging were realized. The ultrasonic phased array technology can detect kinds of defects in electron beam welding (EBW) quickly and easily.

  19. 76 FR 55944 - In the Matter of Certain Electronic Devices With Image Processing Systems, Components Thereof...

    Science.gov (United States)

    2011-09-09

    ... COMMISSION In the Matter of Certain Electronic Devices With Image Processing Systems, Components Thereof, and... filed by S3 Graphics Co. Ltd. and S3 Graphics Inc. (collectively, ``S3G''). 75 FR 38118 (July 1, 2010... importation of certain electronic devices with image processing systems, components thereof, and...

  20. Measurement of changes in surface profile due to wear using a 147Pm β particle backscatter technique. 2

    International Nuclear Information System (INIS)

    A 147Pm β particle backscatter instrument has been developed and its applications to the measurement of changes in the surface profiles, due to wear, of dental restorations is described. The response of the β particle backscatter instrument to small changes in surface profile are adequately described by a model based on the known behaviour of backscattered electrons. The simulated wear of dental amalgam restorations, composite resin restorations and metal-coated replicas has been studied using this technique. The β particle backscatter instrument is capable of detecting changes of the order of 15 μm in the profile of irregularly shaped surfaces. (Auth.)

  1. Generation and Investigation of Backscatter Mosaics using TerraSAR-X Data

    OpenAIRE

    Rizzoli, Paola; Bräutigam, Benjamin; Wollstadt, Steffen; Mittermayer, Josef

    2010-01-01

    Global backscatter data is required for accurate performance estimation and instrument commanding inside the TerraSAR-X and TanDEM-X missions. The goal of this work is the generation of an X-Band backscatter map by assembling images acquired by the TSX satellite. The complete data ground coverage will be achievable with TanDEM-X mission data. An interpolator, that allows the estimation of the on ground backscatter for any required polarization and incidence angle from the available data, has ...

  2. The relationship between VHF radar auroral backscatter amplitude and Doppler velocity: a statistical study

    Directory of Open Access Journals (Sweden)

    B. A. Shand

    Full Text Available A statistical investigation of the relationship between VHF radar auroral backscatter intensity and Doppler velocity has been undertaken with data collected from 8 years operation of the Wick site of the Sweden And Britain Radar-auroral Experiment (SABRE. The results indicate three different regimes within the statistical data set; firstly, for Doppler velocities <200 m s–1, the backscatter intensity (measured in decibels remains relatively constant. Secondly, a linear relationship is observed between the backscatter intensity (in decibels and Doppler velocity for velocities between 200 m s–1 and 700 m s–1. At velocities greater than 700 m s–1 the backscatter intensity saturates at a maximum value as the Doppler velocity increases. There are three possible geophysical mechanisms for the saturation in the backscatter intensity at high phase speeds: a saturation in the irregularity turbulence level, a maximisation of the scattering volume, and a modification of the local ambient electron density. There is also a difference in the dependence of the backscatter intensity on Doppler velocity for the flow towards and away from the radar. The results for flow towards the radar exhibit a consistent relationship between backscatter intensity and measured velocities throughout the solar cycle. For flow away from the radar, however, the relationship between backscatter intensity and Doppler velocity varies during the solar cycle. The geometry of the SABRE system ensures that flow towards the radar is predominantly associated with the eastward electrojet, and flow away is associated with the westward electrojet. The difference in the backscatter intensity variation as a function of Doppler velocity is attributed to asymmetries between the eastward and westward electrojets and the geophysical parameters controlling the backscatter amplitude.

  3. Technical characterization by image analysis: an automatic method of mineralogical studies

    International Nuclear Information System (INIS)

    The application of a modern method of image analysis fully automated for the study of grain size distribution modal assays, degree of liberation and mineralogical associations is discussed. The image analyser is interfaced with a scanning electron microscope and an energy dispersive X-rays analyser. The image generated by backscattered electrons is analysed automatically and the system has been used in accessment studies of applied mineralogy as well as in process control in the mining industry. (author)

  4. Scanning electron microscope images of uncoated microfossils: applications, perspectives and limitations

    OpenAIRE

    Spezzaferri, Silvia; Neururer, Christoph; Pirkenseer, Claudius; Grobéty, Bernard

    2007-01-01

    We present a recently developed method using a field emission scanning electron microscope (FEG) to view and photograph microfossil specimens that are not coated by conductive material. The FEG microscope provides high electron flux and offers the option to capture images at low beam voltage. Balancing incident energy with absorbed energy from the detector leads to charge-free images of non-conductive material. As an example of the application, we show images of planktonic foraminifers and os...

  5. Imaging techniques for a high-power THz free electron laser

    International Nuclear Information System (INIS)

    Two imaging techniques based on the thermal effect have been developed and implemented for recording images using radiation of a high-power terahertz free electron laser. The techniques were applied for the visualization of images in experiments on classical optics, as well as in a holographic experiment

  6. Structure of mitochondrial F1-ATPase studied by electron microscopy and image processing

    NARCIS (Netherlands)

    Boekema, Egbert J.; Berden, Jan A.; Heel, Marin G. van

    1986-01-01

    The structure of soluble F1-ATPase (EC 3.6.1.3) has been investigated by computer analysis of individual molecular images extracted from electron micrographs of negatively stained particles. A total of 1241 images was interactively selected from several digitized micrographs and these images were su

  7. Theoretical analysis of backscattered polarization patterns of turbid media containing glucose

    Institute of Scientific and Technical Information of China (English)

    Lanqing Xu; Hui Li; Shusen Xie

    2007-01-01

    Single scattering model and Stokes-Mueller formalism are introduced to investigate the influence of glucose on backscattered polarization patterns in turbid media. Glucose molecules rotate the polarization plane and induce changes in backscattered Mueller matrix patterns. Some Mueller matrix elements present higher optical rotation as the concentration of glucose augments. Using image subtraction and integration,linear relationship between low glucose concentration in the physiological range and optical rotation degree can be derived.

  8. Features of atomic images reconstructed from photoelectron, Auger electron, and internal detector electron holography using SPEA-MEM

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, Tomohiro, E-mail: matusita@spring8.or.jp [Japan Synchrotron Radiation Research Institute, SPring-8, Sayo, Hyogo 679-5198 (Japan); Matsui, Fumihiko [Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0192 (Japan)

    2014-08-15

    Highlights: • We develop a 3D atomic image reconstruction algorithm for photoelectron, Auger electron, and internal detector holography. • We examine the shapes of the atomic images reconstructed by using a developed kernel function. • We examine refraction effect at surface, limitation effect of the hologram data, energy resolution effect, and angular resolution effect. • These discussions indicate the experimental requirements to obtain the clear 3D atomic image. - Abstract: Three-dimensional atomic images can be reconstructed from photoelectron, Auger electron, and internal detector electron holograms using a scattering pattern extraction algorithm using the maximum entropy method (SPEA-MEM) that utilizes an integral transform. An integral kernel function for the integral transform is the key to clear atomic image reconstruction. We composed the kernel function using a scattering pattern function and estimated its ability. Image distortion caused by multiple scattering was also evaluated. Four types of Auger electron wave functions were investigated, and the effect of these wave function types was estimated. In addition, we addressed refraction at the surface, the effects of data limitation, and energy and angular resolutions.

  9. Detection of defects in foam thermal insulation using lateral migration backscatter x-ray radiography

    Science.gov (United States)

    Dugan, Edward T.; Jacobs, Alan M.; Shedlock, Dan; Ekdahl, Dan

    2004-10-01

    A new Compton x-ray backscatter imaging technique called lateral migration radiography (LMR) has been successfully applied to the detection of voids and delaminations in the foam thermal insulation used on the shuttle external tank. LMR employs detection of selected scatter field velocity components, by using specially designed detectors and detector collimators, to achieve high image contrast. LMR is based on image contrast generated by migration of probe x-ray radiation in directions transverse to the illumination radiation beam. Because LMR is sensitive to electron density variations in these directions, thin, but large density variations, such as cracks and delaminations, generate signal-to-background ratios sufficient to produce images of features which are not even detectable in the usually interrogated thin dimension. The examined foam thermal insulation test panels consist of aluminum plates onto which the sprayed-on foam insulation (SOFI) is applied. Some of the test panels include structural features bolted to the base plate. The SOFI was layed down over the base plate and structure with a thickness varying from a few tens of mm up to a few hundred mm. The test panels included voids and simulated delaminations in the SOFI ranging in cross-sectional size from 6 x 6 mm to 50 x 50 mm. High quality images were acquired using pixels of 2 to 3 mm and irradiation times as low as 0.05 s per pixel.

  10. Compton backscattered and primary X-rays from solar flares: angle dependent Green's function correction for photospheric albedo

    Science.gov (United States)

    Kontar, E. P.; MacKinnon, A. L.; Schwartz, R. A.; Brown, J. C.

    2006-02-01

    The observed hard X-ray (HXR) flux spectrum I(ɛ) from solar flares is a combination of primary bremsstrahlung photons I_P(ɛ) with a spectrally modified component from photospheric Compton backscatter of downward primary emission. The latter can be significant, distorting or hiding the true features of the primary spectrum which are key diagnostics for acceleration and propagation of high energy electrons and of their energy budget. For the first time in solar physics, we use a Green's function approach to the backscatter spectral deconvolution problem, constructing a Green's matrix including photoelectric absorption. This approach allows spectrum-independent extraction of the primary spectrum for several HXR flares observed by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). We show that the observed and primary spectra differ very substantially for flares with hard spectra close to the disk centre. We show in particular that the energy dependent photon spectral index γ (ɛ)=-d log I/d log ɛ is very different for I_P(ɛ) and for I(ɛ) and that inferred mean source electron spectra F(E) differ greatly. Even for a forward fitting of a parametric F(E) to the data, a clear low-energy cutoff required to fit I(ɛ) essentially disappears when the fit is to I_P(ɛ) - i.e. when albedo correction is included. The self-consistent correction for backscattered photons is thus shown to be crucial in determining the energy spectra of flare accelerated electrons, and hence their total number and energy.

  11. Image formation mechanisms in scanning electron microscopy of carbon nanotubes, and retrieval of their intrinsic dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Jackman, H., E-mail: henrik.jackman@kau.se [Department of Physics and Electrical Engineering, Karlstad University, SE-651 88 Karlstad (Sweden); Krakhmalev, P. [Department of Mechanical and Materials Engineering, Karlstad University, SE-651 88 Karlstad (Sweden); Svensson, K. [Department of Physics and Electrical Engineering, Karlstad University, SE-651 88 Karlstad (Sweden)

    2013-01-15

    We present a detailed analysis of the image formation mechanisms that are involved in the imaging of carbon nanotubes with scanning electron microscopy (SEM). We show how SEM images can be modelled by accounting for surface enhancement effects together with the absorption coefficient for secondary electrons, and the electron-probe shape. Images can then be deconvoluted, enabling retrieval of the intrinsic nanotube dimensions. Accurate estimates of their dimensions can thereby be obtained even for structures that are comparable to the electron-probe size (on the order of 2 nm). We also present a simple and robust model for obtaining the outer diameter of nanotubes without any detailed knowledge about the electron-probe shape. -- Highlights: Black-Right-Pointing-Pointer We model the image formation of free-standing carbon nanotubes in SEM. Black-Right-Pointing-Pointer The electron-probe shape is characterized from SEM-images. Black-Right-Pointing-Pointer We use the electron-probe shape to deconvolute SEM-images of carbon nanotubes. Black-Right-Pointing-Pointer We present a simple method for retrieval of intrinsic nanotube dimensions.

  12. Incorporate elastic and inelastic scattering into image calculation for low-voltage transmission electron microscope

    OpenAIRE

    Lee, Zhongbo

    2014-01-01

    In this work, we have studied the dependence of image contrast on different parameters for low voltage TEM by means of image calculation. For pure elastic scattering, we have utilized a semi-experimental model which calculates the image by averaging over the energy distribution of the elastically scattered imaging electrons, derived from the experimental EELS data. The calculations were performed for graphene under the accelerating voltage of 80 kV and 20 kV. We have investigated the influen...

  13. Monokinetic electron backsttering from amorphous or polycrystalline specimens

    International Nuclear Information System (INIS)

    We have considered the interaction of electrons with thin amorphous specimens: one part of these electrons is transmitted through the substance, the other being backscattered. This last phenomena, which is not perfectly understood, has been studied in the energy range from 0.3 to 3 MeV. First this work deals with the realization of a fully automatic apparatus which has been adapted to the column of the 3 MeV electron microscope of the HVFM laboratory in Toulouse. The variation of the transmission and backscattering coefficients, for amorphous and polycrystalline specimens, is determined. From this coefficient the electron range in this substance can be deduced. In addition the experimental results can be used to understand the image contrast in scanning electron microscopy. A short presentation of the cross-section, introduces the theoretical study of Monte-Carlo calculation. The Monte-Carlo calculation is used to take into account all elementary processus, which take place during electron scattering

  14. On the application of electron cyclotron emission imaging to the validation of theoretical models of magnetohydrodynamic activity

    NARCIS (Netherlands)

    Tobias, B. J.; Boivin, R. L.; Boom, J. E.; Classen, I.G.J.; Domier, C.W.; Donne, A. J. H.; Heidbrink, W. W.; N C Luhmann Jr.,; Munsat, T.; Muscatello, C. M.; Nazikian, R.; Park, H. K.; Spong, D. A.; Turnbull, A. D.; VanZeeland, M. A.; Yun, G. S.

    2011-01-01

    Two-dimensional (2D) imaging of electron temperature perturbations provides a powerful constraint for validating theoretical models describing magnetohydrodynamic plasma behavior. In observation of Alfven wave induced temperature fluctuations, electron cyclotron emission imaging provides unambiguous

  15. Laser induced electron diffraction: a tool for molecular orbital imaging

    CERN Document Server

    Peters, Michel; Charron, Eric; Keller, Arne; Atabek, Osman

    2012-01-01

    We explore the laser-induced ionization dynamics of N2 and CO2 molecules subjected to a few-cycle, linearly polarized, 800\\,nm laser pulse using effective two-dimensional single active electron time-dependent quantum simulations. We show that the electron recollision process taking place after an initial tunnel ionization stage results in quantum interference patterns in the energy resolved photo-electron signals. If the molecule is initially aligned perpendicular to the field polarization, the position and relative heights of the associated fringes can be related to the molecular geometrical and orbital structure, using a simple inversion algorithm which takes into account the symmetry of the initial molecular orbital from which the ionized electron is produced. We show that it is possible to extract inter-atomic distances in the molecule from an averaged photon-electron signal with an accuracy of a few percents.

  16. Effects of image noise on contact edge roughness and critical dimension uniformity measurement in synthesized scanning electron microscope images

    Science.gov (United States)

    Constantoudis, Vassilios; Kuppuswamy, Vijaya-Kumar Murugesan; Gogolides, Evangelos

    2013-01-01

    We study the effects of noise in scanning electron microscope (SEM) images on the size and roughness of contact holes when they are measured using top-down SEM images. The applied methodology is based on the generation of synthesized top-down SEM images, including several model contact edges with controlled roughness, critical dimension (CD) uniformity, and noise. The sources of image noise can be the shot noise of SEM electron beams and microscope electronics. The results show that noise reduces CD and correlation length while it increases the rms value of contact edge roughness (CER). CD variation is increased with noise in images with smooth and identical contacts, whereas it remains almost unaltered in images including rough contacts with CD nonuniformity. Furthermore, we find that the application of a noise-smoothing filter before image analysis rectifies the values of CD (at small filter parameter) and of rms and correlation length (at larger filter parameters), whereas it leads to marginally larger deviations from the true values of CD variation. Quantitative assessment of the model predictions reveals that the noise-induced variations of CD and CER values are less important compared with those caused by process stochasticity and material inhomogeneities.

  17. Estimating slash pine biomass using radar backscatter

    Science.gov (United States)

    Hussin, Yousif Ali; Reich, Robin M.; Hoffer, Roger M.

    1991-01-01

    L-band HV multiple-incidence-angle aircraft synthetic aperture radar (SAR) data were analyzed in relation to average stand biomass, basal area, and tree height for 55 slash pine plantations located in northern Florida. This information was used to develop a system of equations to predict average stand biomass as a function of L-band (24.5-cm) radar backscatter. The system of equations developed in this study using three-stage least-squares and combinatorial screening accounted for 97 percent of the variability observed in average stand biomass per hectare. When applied to an independent data set, the biomass equations had an average bias of less than 1 percent with a standard error of approximately 3 percent. These results indicate that future Shuttle Imaging Radar Systems (e.g., SIR-C, which will have cross-polarized radar sensors) should be able to obtain better estimates of forest biomass than were obtained with previous satellite radar missions, which utilized only HH-polarized SAR data.

  18. NOAA TIFF Graphic- 0.5m Backscatter Mosaic of St. Croix (Buck Island), US Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 1 meter resolution backscatter mosaic of the north shore of Buck Island, St. Croix, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography...

  19. Backscatter Mosaic used to identify, delineate and classify moderate-depth benthic habitats around St. John, USVI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 2x2 meter resolution backscatter mosaic of the moderate-depth portion of the NPS's Virgin Islands Coral Reef National Monument, south of St....

  20. NOAA TIFF Graphic - 0.5 meter Backscatter Mosaic of St. John, U.S. Virgin Islands, 2004

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 0.5 meter resolution backscatter mosaic of the southern shore of St. John, US Virgin Islands.NOAA's NOS/NCCOS/CCMA Biogeography Team and...

  1. 75 FR 38118 - In the Matter of Certain Electronic Devices With Image Processing Systems, Components Thereof...

    Science.gov (United States)

    2010-07-01

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION In the Matter of Certain Electronic Devices With Image Processing Systems, Components Thereof, and Associated Software; Notice of Investigation AGENCY: U.S. International Trade Commission. ACTION:...

  2. 77 FR 4059 - Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof; Receipt...

    Science.gov (United States)

    2012-01-26

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof; Receipt... Trade Commission. ACTION: Notice. SUMMARY: Notice is hereby given that the U.S. International...

  3. 77 FR 32995 - Certain Electronic Imaging Devices Corrected: Notice of Receipt of Complaint; Solicitation of...

    Science.gov (United States)

    2012-06-04

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Electronic Imaging Devices Corrected: Notice of Receipt of Complaint; Solicitation of Comments Relating to the Public Interest AGENCY: U.S. International Trade Commission. ACTION:...

  4. 77 FR 31875 - Certain Electronic Imaging Devices; Notice of Receipt of Complaint; Solicitation of Comments...

    Science.gov (United States)

    2012-05-30

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Electronic Imaging Devices; Notice of Receipt of Complaint; Solicitation of Comments Relating to the Public Interest AGENCY: U.S. International Trade Commission. ACTION: Notice....

  5. 77 FR 11588 - Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof

    Science.gov (United States)

    2012-02-27

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof AGENCY: U.S. International Trade Commission. ACTION: Notice. SUMMARY: Notice is hereby given that a...

  6. Imaging the dynamics of free-electron Landau states.

    Science.gov (United States)

    Schattschneider, P; Schachinger, Th; Stöger-Pollach, M; Löffler, S; Steiger-Thirsfeld, A; Bliokh, K Y; Nori, Franco

    2014-08-08

    Landau levels and states of electrons in a magnetic field are fundamental quantum entities underlying the quantum Hall and related effects in condensed matter physics. However, the real-space properties and observation of Landau wave functions remain elusive. Here we report the real-space observation of Landau states and the internal rotational dynamics of free electrons. States with different quantum numbers are produced using nanometre-sized electron vortex beams, with a radius chosen to match the waist of the Landau states, in a quasi-uniform magnetic field. Scanning the beams along the propagation direction, we reconstruct the rotational dynamics of the Landau wave functions with angular frequency ~100 GHz. We observe that Landau modes with different azimuthal quantum numbers belong to three classes, which are characterized by rotations with zero, Larmor and cyclotron frequencies, respectively. This is in sharp contrast to the uniform cyclotron rotation of classical electrons, and in perfect agreement with recent theoretical predictions.

  7. Imaging instantaneous electron flow with ultrafast resonant x-ray scattering

    CERN Document Server

    Popova-Gorelova, Daria

    2015-01-01

    We propose a novel way to image dynamical properties of nonstationary electron systems using ultrafast resonant x-ray scattering. Employing a rigorous theoretical analysis within the framework of quantum electrodynamics, we demonstrate that a single scattering pattern from a nonstationary electron system encodes the instantaneous interatomic electron current in addition to the structural information usually obtained by resonant x-ray scattering from stationary systems. Thus, inelastic contributions that are indistinguishable from elastic processes induced by a broadband probe pulse, instead of being a concern, serve as an advantage for time-resolved resonant x-ray scattering. Thereby, we propose an approach combining elastic and inelastic resonant x-ray scattering for imaging dynamics of nonstationary electron systems in both real space and real time. In order to illustrate its power, we show how it can be applied to image the electron hole current in an ionized diatomic molecule.

  8. 3D Imaging of mammalian cells with ion-abrasion scanning electron microscopy

    OpenAIRE

    Heymann, Jurgen A. W.; Shi, Dan; Kim, Sang; Bliss, Donald; Milne, Jacqueline L. S.; Subramaniam, Sriram

    2008-01-01

    Understanding the hierarchical organization of molecules and organelles within the interior of large eukaryotic cells is a challenge of fundamental interest in cell biology. We are using ion-abrasion scanning electron microscopy (IA-SEM) to visualize this hierarchical organization in an approach that combines focused ion-beam milling with scanning electron microscopy. Here, we extend our previous studies on imaging yeast cells to image subcellular architecture in human melanoma cells and mela...

  9. Atomic scale imaging and spectroscopy of individual electron trap states using force detected dynamic tunnelling

    International Nuclear Information System (INIS)

    We report the first atomic scale imaging and spectroscopic measurements of electron trap states in completely non-conducting surfaces by dynamic tunnelling force microscopy/spectroscopy. Single electrons are dynamically shuttled to/from individual states in thick films of hafnium silicate and silicon dioxide. The new method opens up surfaces that are inaccessible to the scanning tunnelling microscope for imaging and spectroscopy on an atomic scale.

  10. Post calibration of the two-dimensional electron cyclotron emission imaging instrument with electron temperature characteristics of the magnetohydrodynamic instabilities

    Energy Technology Data Exchange (ETDEWEB)

    Choi, M. J., E-mail: mjchoi@nfri.re.kr [National Fusion Research Institute, Daejeon 34133 (Korea, Republic of); Park, H. K. [National Fusion Research Institute, Daejeon 34133 (Korea, Republic of); Ulsan National Institute of Science and Technology, Ulsan 689-798 (Korea, Republic of); Yun, G. S.; Nam, Y. B.; Choe, G. H. [Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784 (Korea, Republic of); Lee, W. [Ulsan National Institute of Science and Technology, Ulsan 689-798 (Korea, Republic of); Jardin, S. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2016-01-15

    The electron cyclotron emission imaging (ECEI) instrument is widely used to study the local electron temperature (T{sub e}) fluctuations by measuring the ECE intensity I{sub ECE} ∝ T{sub e} in tokamak plasmas. The ECEI measurement is often processed in a normalized fluctuation quantity against the time averaged value due to complication in absolute calibration. In this paper, the ECEI channels are relatively calibrated using the flat T{sub e} assumption of the sawtooth crash or the tearing mode island and a proper extrapolation. The 2-D relatively calibrated electron temperature (T{sub e,rel}) images are reconstructed and the displacement amplitude of the magnetohydrodynamic modes can be measured for the accurate quantitative growth analysis.

  11. Some Theoretical Estimations of Spatial Distribution of Compton Backscattered Laser Photons Beam

    CERN Document Server

    Peresunko, Yu P

    2003-01-01

    Spatial distribution of intensity, degree and direction of linear polarization of tagged photon beam, which is obtained due to Compton backscattering of laser light on high-energy electron beam, are calculated. Effects of angular dispersion and spatial spread of electron beam are taken into account. Calculations have been carried out for the example of LEGS facility.

  12. Simulation Studies of the Backscattering Signal in HSRL Technique

    CERN Document Server

    Georgakopoulou, Angelika

    2012-01-01

    The technique of High Spectral Resolution Lidar (HSRL) for atmospheric monitoring allows the determination of the aerosol to molecular ratio and can be used in UHECR Observatories using air fluorescence telescopes. By this technique a more accurate estimate of the Cherenkov radiation superimposed to the fluorescence signal can be achieved. A laboratory setup was developed to determine the backscattering coefficients using microparticles diluted in water and diffusion interfaces. In this setup we used a CW SLM laser at 532 nm and a 250 mm Newtonian telescope. Simulations of the above experimental configuration have been made using Scatlab\\c{opyright}, FINESSE\\c{opyright} 0.99.8 and MATLAB\\c{opyright} and are presented in this work. We compare the simulated 2-dimensional Fabry-Perot fringe images of the backscattering signal recorded in the CCD sensor with that of experimental ones. Additionally, we simulated the backscattering of the laser beam by the atmosphere at a height of 2000 m and we have studied the in...

  13. Stimulated Raman backscattering at high laser intensities

    Energy Technology Data Exchange (ETDEWEB)

    Skoric, M.M. [Vinca Inst. of Nuclear Sciences, Belgrade (Yugoslavia); Tajima, Toshiki; Sasaki, Akira; Maluckov, A.; Jovanovic, M.

    1998-03-01

    Signatures of Stimulated Raman backscattering of a short-pulse high-intensity laser interacting with an underdense plasma are discussed. We introduce a nonlinear three-wave interaction model that accounts for laser pump depletion and relativistic detuning. A mechanism is revealed based on a generic route to chaos, that predicts a progressive increase of the backscatter complexity with a growing laser intensity. Importance of kinetic effects is outlined and demonstrated in fluid-hybrid and particle simulations. As an application, we show that spectral anomalies of the backscatter, predicted by the above model, are consistent with recent sub-picosecond, high-intensity laser gas-target measurements at Livermore and elsewhere. Finally, a recently proposed scheme for generation of ultra-short, low-prepulse laser pulses by Raman backscattering in a thin foil target, is shown. (author)

  14. Commissioning of electron cyclotron emission imaging instrument on the DIII-D tokamak and first data

    NARCIS (Netherlands)

    Tobias, B.; Domier, C.W.; Liang, T.; Kong, X.; Yu, L.; Yun, G. S.; Park, H. K.; Classen, I.G.J.; Boom, J. E.; Donne, A. J. H.; Munsat, T.; Nazikian, R.; Van Zeeland, M.; Boivin, R. L.; N C Luhmann Jr.,

    2010-01-01

    A new electron cyclotron emission imaging diagnostic has been commissioned on the DIII-D tokamak. Dual detector arrays provide simultaneous two-dimensional images of T-e fluctuations over radially distinct and reconfigurable regions, each with both vertical and radial zoom capability. A total of 320

  15. An Anomalous Contrast of Insulators in Scanning Electron Microscope: The Split Image

    OpenAIRE

    Xie, Lilin; Zhang, Xiaona

    2016-01-01

    A novel phenomenon of anomalous contrast in scanning electron microscope when the instrument is used to observe an insulator specimen with a wolfram probe, we called double imaging, is reported in this article. We give a detail analysis of this phenomenon in its occurrence, and discuss the influence of the added probe to internal electric field which lead to the occurrence of double imaging.

  16. Magnetic imaging with a Zernike-type phase plate in a transmission electron microscope

    DEFF Research Database (Denmark)

    Pollard, Shawn; Malac, Marek; Beleggia, Marco;

    2013-01-01

    We demonstrate the use of a hole-free phase plate (HFPP) for magnetic imaging in transmission electron microscopy by mapping the domain structure in PrDyFeB samples. The HFPP, a Zernike-like imaging method, allows for detecting magnetic signals in-focus to correlate the sample crystal structure...

  17. Sparse sampling and reconstruction for electron and scanning probe microscope imaging

    Science.gov (United States)

    Anderson, Hyrum; Helms, Jovana; Wheeler, Jason W.; Larson, Kurt W.; Rohrer, Brandon R.

    2015-07-28

    Systems and methods for conducting electron or scanning probe microscopy are provided herein. In a general embodiment, the systems and methods for conducting electron or scanning probe microscopy with an undersampled data set include: driving an electron beam or probe to scan across a sample and visit a subset of pixel locations of the sample that are randomly or pseudo-randomly designated; determining actual pixel locations on the sample that are visited by the electron beam or probe; and processing data collected by detectors from the visits of the electron beam or probe at the actual pixel locations and recovering a reconstructed image of the sample.

  18. A single probe for imaging photons, electrons and physical forces

    Science.gov (United States)

    Pilet, Nicolas; Lisunova, Yuliya; Lamattina, Fabio; Stevenson, Stephanie E.; Pigozzi, Giancarlo; Paruch, Patrycja; Fink, Rainer H.; Hug, Hans J.; Quitmann, Christoph; Raabe, Joerg

    2016-06-01

    The combination of complementary measurement techniques has become a frequent approach to improve scientific knowledge. Pairing of the high lateral resolution scanning force microscopy (SFM) with the spectroscopic information accessible through scanning transmission soft x-ray microscopy (STXM) permits assessing physical and chemical material properties with high spatial resolution. We present progress from the NanoXAS instrument towards using an SFM probe as an x-ray detector for STXM measurements. Just by the variation of one parameter, the SFM probe can be utilised to detect either sample photo-emitted electrons or transmitted photons. This allows the use of a single probe to detect electrons, photons and physical forces of interest. We also show recent progress and demonstrate the current limitations of using a high aspect ratio coaxial SFM probe to detect photo-emitted electrons with very high lateral resolution. Novel probe designs are proposed to further progress in using an SFM probe as a STXM detector.

  19. Molecular shape of Lumbricus terrestris erythrocruorin studied by electron microscopy and image analysis

    NARCIS (Netherlands)

    Boekema, Egbert J.; Heel, Marin van

    1989-01-01

    The molecular structure of erythrocruorin (hemoglobin) from Lumbricus terrestris has been studied by electron microscopy of negatively stained particles. Over 1000 molecular projections were selected from a number of electron micrographs and were then classified by multivariate statistical image-pro

  20. Image of electron densities from line and plane projections

    Science.gov (United States)

    Kontrym-Sznajd, G.; Samsel-Czekała, M.; Biasini, M.

    2008-04-01

    We compare Fourier transforms with orthogonal polynomials techniques applied in reconstructing three-dimensional electron-positron momentum densities from two-dimensional angular correlation of annihilation radiation (2D-ACAR) spectra and electron momentum densities from one-dimensional Compton profiles (1D-CP). In the case of Fourier transforms, we show results for two different algorithms: filtered back projection and Fourier-Bessel method. These techniques are presented for 2D-ACAR spectra in Y, ErGa3 and model profiles.

  1. Applications of Secondary Electron Composition Contrast Imaging Method in Microstructure Studies on Heterojunction Semiconductor Devices and Multilayer Materials

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The principle, imaging condition and experimental method for obtaining high resolution composition contrast in secondary electron image were described. A new technique of specimen preparation for secondary electron composition contrast observation was introduced and discussed. By using multilayer P+-Si1-xGex/p-Si heterojunction internal photoemission infrared detector as an example, the applications of secondary electron composition contrast imaging in microstructure studies on heterojunction semiconducting materials and devices were stated. The characteristics of the image were compared with the ordinary transmission electron diffraction contrast image. The prospects of applications of the imaging method in heterojunction semiconductor devices and multilayer materials are also discussed.

  2. Classification of kidney and liver tissue using ultrasound backscatter data

    Science.gov (United States)

    Aalamifar, Fereshteh; Rivaz, Hassan; Cerrolaza, Juan J.; Jago, James; Safdar, Nabile; Boctor, Emad M.; Linguraru, Marius G.

    2015-03-01

    Ultrasound (US) tissue characterization provides valuable information for the initialization of automatic segmentation algorithms, and can further provide complementary information for diagnosis of pathologies. US tissue characterization is challenging due to the presence of various types of image artifacts and dependence on the sonographer's skills. One way of overcoming this challenge is by characterizing images based on the distribution of the backscatter data derived from the interaction between US waves and tissue. The goal of this work is to classify liver versus kidney tissue in 3D volumetric US data using the distribution of backscatter US data recovered from end-user displayed Bmode image available in clinical systems. To this end, we first propose the computation of a large set of features based on the homodyned-K distribution of the speckle as well as the correlation coefficients between small patches in 3D images. We then utilize the random forests framework to select the most important features for classification. Experiments on in-vivo 3D US data from nine pediatric patients with hydronephrosis showed an average accuracy of 94% for the classification of liver and kidney tissues showing a good potential of this work to assist in the classification and segmentation of abdominal soft tissue.

  3. Imaging the potential distribution of charged adsorbates on graphene by low-energy electron holography

    CERN Document Server

    Latychevskaia, Tatiana; Escher, Conrad; Fink, Hans-Werner

    2016-01-01

    While imaging individual atoms can routinely be achieved in high resolution transmission electron microscopy, visualizing the potential distribution of individually charged adsorbates leading to a phase shift of the probing electron wave is still a challenging task. Since low-energy electrons are sensitive to localized potential gradients, we employed this tool in the 30 eV kinetic energy range to visualize the potential distribution of localized charged adsorbates present on free-standing graphene.

  4. Imaging electron dynamics with time- and angle-resolved photoelectron spectroscopy

    Science.gov (United States)

    Popova-Gorelova, Daria; Küpper, Jochen; Santra, Robin

    2016-07-01

    We theoretically study how time- and angle-resolved photoemission spectroscopy can be applied for imaging coherent electron dynamics in molecules. We consider a process in which a pump pulse triggers coherent electronic dynamics in a molecule by creating a valence electron hole. An ultrashort extreme ultraviolet probe pulse creates a second electron hole in the molecule. Information about the electron dynamics is accessed by analyzing angular distributions of photoemission probabilities at a fixed photoelectron energy. We demonstrate that a rigorous theoretical analysis, which takes into account the indistinguishability of transitions induced by the ultrashort, broadband probe pulse and electron hole correlation effects, is necessary for the interpretation of time- and angle-resolved photoelectron spectra. We show how a Fourier analysis of time- and angle-resolved photoelectron spectra from a molecule can be applied to follow its electron dynamics by considering photoelectron distributions from an indole molecular cation with coherent electron dynamics.

  5. Spectral variability of the particulate backscattering ratio

    Science.gov (United States)

    Whitmire, A. L.; Boss, E.; Cowles, T. J.; Pegau, W. S.

    2007-05-01

    The spectral dependency of the particulate backscattering ratio is relevant in the fields of ocean color inversion, light field modeling, and inferring particle properties from optical measurements. Aside from theoretical predictions for spherical, homogeneous particles, we have very limited knowledge of the actual in situ spectral variability of the particulate backscattering ratio. This work presents results from five research cruises that were conducted over a three-year period. Water column profiles of physical and optical properties were conducted across diverse aquatic environments that offered a wide range of particle populations. The main objective of this research was to examine the behavior of the spectral particulate backscattering ratio in situ, both in terms of its absolute magnitude and its variability across visible wavelengths, using over nine thousand 1-meter binned data points for each of five wavelengths of the spectral particulate backscattering ratio. Our analysis reveals no spectral dependence of the particulate backscattering ratio within our measurement certainty, and a geometric mean value of 0.013 for this dataset. This is lower than the commonly used value of 0.0183 from Petzold’s integrated volume scattering data. Within the first optical depth of the water column, the mean particulate backscattering ratio was 0.010.

  6. ILC beam energy measurement by means of laser Compton backscattering

    Energy Technology Data Exchange (ETDEWEB)

    Muchnoi, N. [Budker Inst. for Nuclear Physics, Novosibirsk (Russian Federation); Schreiber, H.J.; Viti, M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2008-10-15

    A novel, non-invasive method of measuring the beam energy at the International Linear Collider is proposed. Laser light collides head-on with beam particles and either the energy of the Compton scattered electrons near the kinematic end-point is measured or the positions of the Compton backscattered {gamma}-rays, the edge electrons and the unscattered beam particles are recorded. A compact layout for the Compton spectrometer is suggested. It consists of a bending magnet and position sensitive detectors operating in a large radiation environment. Several options for high spatial resolution detectors are discussed. Simulation studies support the use of an infrared or green laser and quartz fiber detectors to monitor the backscattered photons and edge electrons. Employing a cavity monitor, the beam particle position downstream of the magnet can be recorded with submicrometer precision. Such a scheme provides a feasible and promising method to access the incident beam energy with precisions of 10{sup -4} or better on a bunch-to-bunch basis while the electron and positron beams are in collision. (orig.)

  7. Imaging the dynamics of free-electron Landau states.

    Science.gov (United States)

    Schattschneider, P; Schachinger, Th; Stöger-Pollach, M; Löffler, S; Steiger-Thirsfeld, A; Bliokh, K Y; Nori, Franco

    2014-01-01

    Landau levels and states of electrons in a magnetic field are fundamental quantum entities underlying the quantum Hall and related effects in condensed matter physics. However, the real-space properties and observation of Landau wave functions remain elusive. Here we report the real-space observation of Landau states and the internal rotational dynamics of free electrons. States with different quantum numbers are produced using nanometre-sized electron vortex beams, with a radius chosen to match the waist of the Landau states, in a quasi-uniform magnetic field. Scanning the beams along the propagation direction, we reconstruct the rotational dynamics of the Landau wave functions with angular frequency ~100 GHz. We observe that Landau modes with different azimuthal quantum numbers belong to three classes, which are characterized by rotations with zero, Larmor and cyclotron frequencies, respectively. This is in sharp contrast to the uniform cyclotron rotation of classical electrons, and in perfect agreement with recent theoretical predictions. PMID:25105563

  8. Electron beam density study using a portable slit imaging system at the Shanghai Electron Beam Ion Trap

    Institute of Scientific and Technical Information of China (English)

    Yang Yang; Lu Di; Pu Yun-Qing; Yao Ke; Chen wei-Dong; Xiao Jun; Geng Zhi-xian; Roger Hutton; Zou Ya-Ming

    2011-01-01

    In this work,a portable slit imaging system is developed to study both the electron beam diameter and the profile of the newly developed Shanghai Electron Beam Ion Trap(Shanghai EBIT).Images are detected by a charge coupled device(CCD)sensitive to both X rays and longer wavelength photons(up to visible).Large scale ray tracings were conducted for correcting the image broadening effects caused by the finite slit width and the finite width of the CCD pixels.A numerical de-convolution method was developed to analyse and reconstruct the electron beam density distribution in the EBIT.As an example of the measured beam diameter and current density,the FWHM(full width at half maximum)diameter of the electron beam at 81 keV and 120 mA is found to be 76.2 μm and the density 20.00×103 A·cm-2,under a magnetic field of 3 T,including all corrections.

  9. Novel X-ray backscatter technique for detection of dangerous materials: application to aviation and port security

    International Nuclear Information System (INIS)

    Radiological inspections, in general, are the nondestructive testing (NDT) methods to detect the bulk of explosives in large objects. In contrast to personal luggage, cargo or building components constitute a complexity that may significantly hinder the detection of a threat by conventional X-ray transmission radiography. In this article, a novel X-ray backscatter technique is presented for detecting suspicious objects in a densely packed large object with only a single sided access. It consists of an X-ray backscatter camera with a special twisted slit collimator for imaging backscattering objects. The new X-ray backscatter camera is not only imaging the objects based on their densities but also by including the influences of surrounding objects. This unique feature of the X-ray backscatter camera provides new insights in identifying the internal features of the inspected object. Experimental mock-ups were designed imitating containers with threats among a complex packing as they may be encountered in reality. We investigated the dependence of the quality of the X-ray backscatter image on (a) the exposure time, (b) multiple exposures, (c) the distance between object and slit camera, and (d) the width of the slit. At the end, the significant advantages of the presented X-ray backscatter camera in the context of aviation and port security are discussed

  10. Diffractive imaging of transient electronic core-shell structures in a nanoplasma

    CERN Document Server

    Rupp, Daniela; Adolph, Marcus; Gorkhover, Tais; Krikunova, Maria; Müller, Jan-Phillipe; Müller, Maria; Oelze, Tim; Ovcharenko, Yevheniy; Sauppe, Mario; Schorb, Sebastian; Wolter, David; Harmand, Marion; Treusch, Rolf; Bostedt, Christoph; Möller, Thomas

    2016-01-01

    We have recorded the coherent diffraction images of individual xenon clusters using intense extreme ultraviolet free-electron laser pulses tuned to atomic and ionic resonances in order to elucidate the influence of light induced electronic changes on the diffraction pattern. The data show the emergence of a transient core-shell structure within the otherwise homogeneous sample. Simulations indicate that ionization and nanoplasma formation result in a cluster shell with strongly altered refraction. The presented resonant scattering approach enables the imaging of ultrafast electron dynamics with unprecedented spatial resolution on their natural time scale.

  11. Sub-micron imaging of buried integrated circuit structures using scanning confocal electron microscopy.

    Energy Technology Data Exchange (ETDEWEB)

    Frigo, S. P.; Levine, Z.; Zaluzec, N. J.; Materials Science Division; Northern Arizona Univ.; NIST

    2002-09-09

    Two-dimensional images of model integrated circuit components were collected using the technique of scanning confocal electron microscopy. For structures embedded about 5 {mu}m below the surface of a silicon oxide dielectric, a lateral resolution of 76{+-}9 nm was measured. Elemental mapping via x-ray emission spectrometry is demonstrated. A parallax analysis of images taken for various tilt angles to the electron beam allowed determination of the spacing between two wiring planes. The results show that scanning confocal electron microscopy is capable of probing buried structures at resolutions that will be necessary for the inspection of next-generation integrated circuit technology.

  12. Results from the Daresbury Compton backscattering X-ray source

    Science.gov (United States)

    Laundy, D.; Priebe, G.; Jamison, S. P.; Graham, D. M.; Phillips, P. J.; Smith, S. L.; Saveliev, Y.; Vassilev, S.; Seddon, E. A.

    2012-10-01

    The Daresbury Compton Backscattering X-ray Source uses a high power Ti Sapphire laser interacting in head on geometry with electron bunches in the ALICE energy recovery linear accelerator. X-ray photons with peak energy of 21 keV were generated with the accelerator operating at an energy of 29.6 MeV. The spatial profile of the X-rays emitted near the electron beam axis was measured. The characteristics of the X-ray yield measured as a function of relative timing between the laser pulse and the interacting electron bunch was found to be consistent with the modelled intensity behaviour using measured electron and laser beam parameters.

  13. Compton Backscattering for the Calibration of KEDR Tagging System

    CERN Document Server

    Kaminskiy, V V; Zhilich, V N

    2014-01-01

    KEDR detector has the tagging system (TS) to study the gamma-gamma processes. To determine the two-photon invariant mass, the energies of the scattered at small angles electrons and positrons are measured by the magnetic spectrometer embedded into the lattice of the VEPP--4M collider. The energy resolution (scattered electron/positron energy resolution divided by the beam energy) of this spectrometer varies from 0.6% to 0.03% depending on the electron/positron energy. The Compton backscattering of laser radiation on the electron/positron beam is used for the accurate energy scale and resolution calibration of the tagging system. The report covers the design, recent results and current status of the KEDR TS calibration system.

  14. Compton backscattering for the calibration of KEDR tagging system

    Science.gov (United States)

    Kaminskiy, V. V.; Muchnoi, N. Yu; Zhilich, V. N.

    2014-08-01

    KEDR detector has the tagging system (TS) to study the gamma-gamma processes. To determine the two-photon invariant mass, the energies of the scattered at small angles electrons and positrons are measured by the magnetic spectrometer embedded into the lattice of the VEPP-4M collider. The energy resolution (scattered electron/positron energy resolution divided by the beam energy) of this spectrometer varies from 0.6% to 0.03% depending on the electron/positron energy. The Compton backscattering of laser radiation on the electron/positron beam is used for the accurate energy scale and resolution calibration of the tagging system. The report covers the design, recent results and current status of the KEDR TS calibration system.

  15. Separation of image-distortion sources and magnetic-field measurement in scanning electron microscope (SEM).

    Science.gov (United States)

    Płuska, Mariusz; Czerwinski, Andrzej; Ratajczak, Jacek; Katcki, Jerzy; Oskwarek, Lukasz; Rak, Remigiusz

    2009-01-01

    The electron-microscope image distortion generated by electromagnetic interference (EMI) is an important problem for accurate imaging in scanning electron microscopy (SEM). Available commercial solutions to this problem utilize sophisticated hardware for EMI detection and compensation. Their efficiency depends on the complexity of distortions influence on SEM system. Selection of a proper method for reduction of the distortions is crucial. The current investigations allowed for a separation of the distortions impact on several components of SEM system. A sum of signals from distortion sources causes wavy deformations of specimen shapes in SEM images. The separation of various reasons of the distortion is based on measurements of the periodic deformations of the images for different electron beam energies and working distances between the microscope final aperture and the specimen. Using the SEM images, a direct influence of alternating magnetic field on the electron beam was distinguished. Distortions of electric signals in the scanning block of SEM were also separated. The presented method separates the direct magnetic field influence on the electron beam below the SEM final aperture (in the chamber) from its influence above this aperture (in the electron column). It also allows for the measurement of magnetic field present inside the SEM chamber. The current investigations gave practical guidelines for selecting the most efficient solution for reduction of the distortions.

  16. A High-Speed CMOS Image Sensor with Global Electronic Shutter Pixels Using Pinned Diodes

    Science.gov (United States)

    Yasutomi, Keita; Tamura, Toshihiro; Furuta, Masanori; Itoh, Shinya; Kawahito, Shoji

    This paper describes a high-speed CMOS image sensor with a new type of global electronic shutter pixel. A global electronic shutter is necessary for imaging fast-moving objects without motion blur or distortion. The proposed pixel has two potential wells with pinned diode structure for two-stage charge transfer that enables a global electronic shuttering and reset noise canceling. A prototype high-speed image sensor fabricated in 0.18μm standard CMOS image sensor process consists of the proposed pixel array, 12-bit column-parallel cyclic ADC arrays and 192-channel digital outputs. The sensor achieves a good linearity at low-light intensity, demonstrating the perfect charge transfer between two pinned diodes. The input referred noise of the proposed pixel is measured to be 6.3 e-.

  17. Datapath system for multiple electron beam lithography systems using image compression

    Science.gov (United States)

    Yang, Jeehong; Savari, Serap A.; Harris, H. Rusty

    2013-07-01

    The datapath throughput of electron beam lithography systems can be improved by applying lossless image compression to the layout images and using an electron beam writer that contains a decoding circuit packed in single silicon to decode the compressed image on-the-fly. In our past research, we had introduced Corner2, a lossless layout image compression algorithm that achieved significantly better performance in compression ratio, encoding/decoding speed, and decoder memory requirement than Block C4. However, it assumed a somewhat different writing strategy from those currently suggested by multiple electron beam (MEB) system designers. The Corner2 algorithm is modified so that it can support the writing strategy of an MEB system.

  18. Cavitation inception by the backscattering of pressure waves from a bubble interface

    Science.gov (United States)

    Takahira, Hiroyuki; Ogasawara, Toshiyuki; Mori, Naoto; Tanaka, Moe

    2015-10-01

    The secondary cavitation that occurs by the backscattering of focused ultrasound from a primary cavitation bubble caused by the negative pressure part of the ultrasound (Maxwell, et al., 2011) might be useful for the energy exchange due to bubble oscillations in High Intensity Focused Ultrasound (HIFU). The present study is concerned with the cavitation inception by the backscattering of ultrasound from a bubble. In the present experiment, a laser-induced bubble which is generated by a pulsed focused laser beam with high intensity is utilized as a primary cavitation bubble. After generating the bubble, focused ultrasound is emitted to the bubble. The acoustic field and the bubble motion are observed with a high-speed video camera. It is confirmed that the secondary cavitation bubble clouds are generated by the backscattering from the laser-induced bubble. The growth of cavitation bubble clouds is analyzed with the image processing method. The experimental results show that the height and width of the bubble clouds grow in stepwise during their evolution. The direct numerical simulations are also conducted for the backscattering of incident pressure waves from a bubble in order to evaluate a pressure field near the bubble. It is shown that the ratio of a bubble collapse time t0 to a characteristic time of wave propagation tS, η = t0/ts, is an important determinant for generating negative pressure region by backscattering. The minimum pressure location by the backscattering in simulations is in good agreement with the experiment.

  19. Medical Image Resource Center--making electronic teaching files from PACS.

    Science.gov (United States)

    Lim, C C Tchoyoson; Yang, Guo Liang; Nowinski, Wieslaw L; Hui, Francis

    2003-12-01

    A picture archive and communications system (PACS) is a rich source of images and data suitable for creating electronic teaching files (ETF). However, the potential for PACS to support nonclinical applications has not been fully realized: at present there is no mechanism for PACS to identify and store teaching files; neither is there a standardized method for sharing such teaching images. The Medical Image Resource Center (MIRC) is a new central image repository that defines standards for data exchange among different centers. We developed an ETF server that retrieves digital imaging and communication in medicine (DICOM) images from PACS, and enables users to create teaching files that conform to the new MIRC schema. We test-populated our ETF server with illustrative images from the clinical case load of the National Neuroscience Institute, Singapore. Together, PACS and MIRC have the potential to benefit radiology teaching and research.

  20. Evaluation of the health risk of body backscatter x ray scanners; Evaluation du risque sanitaire des scanners corporels a rayons X backscatter

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-01

    Following the attempted attack between Amsterdam and Detroit on the 25 december 2009, the council of interior safety decided a quick display of equipment using more efficient imaging techniques than metals detectors usually in place in French airports. Two technologies of devices are susceptible to be implemented on the airports: scanners using non ionizing radiation, (called millimetric waves) or scanners using ionizing radiation (x radiation, measurement by backscattering called backscatter). This report evaluates the dosimetric impact and the sanitary risk of backscatter x ray scanners and formulates recommendations to authorities to allow them to rule on the type of technology to use. Then, this report gives leads to conceive elements of information to communicate to travelers susceptible to be controlled by a such scanner in a foreign airport. (N.C.)