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Sample records for backscattered electron imaging

  1. Unconventional Imaging with Backscattered Electrons

    Czech Academy of Sciences Publication Activity Database

    Müllerová, Ilona; Mikmeková, Šárka; Hovorka, Miloš; Frank, Luděk

    2011-01-01

    Roč. 17, Suppl. 2 (2011), s. 900-901 ISSN 1431-9276 Institutional research plan: CEZ:AV0Z20650511 Keywords : SEM * low energies * grain contrast * dopant contrast * internal stress Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.007, year: 2011

  2. About the information depth of backscattered electron imaging

    Czech Academy of Sciences Publication Activity Database

    Piňos, Jakub; Mikmeková, Šárka; Frank, Luděk

    2017-01-01

    Roč. 266, č. 3 (2017), s. 335-342 ISSN 0022-2720 Institutional support: RVO:68081731 Keywords : backscattered electrons * information depth * penetration of electrons Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering OBOR OECD: Materials engineering Impact factor: 1.692, year: 2016

  3. Backscattered electron imaging and electron backscattered diffraction in the study of bacterial attachment to titanium alloy structure.

    Science.gov (United States)

    Wang, Anqi; Jones, Ian P; Landini, Gabriel; Mei, Junfa; Tse, Yau Y; Li, Yue X; Ke, Linnan; Huang, Yuanli; Liu, L I; Wang, Chunren; Sammons, Rachel L

    2018-04-01

    The application of secondary electron (SE) imaging, backscattered electron imaging (BSE) and electron backscattered diffraction (EBSD) was investigated in this work to study the bacterial adhesion and proliferation on a commercially pure titanium (cp Ti) and a Ti6Al4V alloy (Ti 64) with respect to substrate microstructure and chemical composition. Adherence of Gram-positive Staphylococcus epidermidis 11047 and Streptococcus sanguinis GW2, and Gram-negative Serratia sp. NCIMB 40259 and Escherichia coli 10418 was compared on cp Ti, Ti 64, pure aluminium (Al) and vanadium (V). The substrate microstructure and the bacterial distribution on these metals were characterised using SE, BSE and EBSD imaging. It was observed that titanium alloy-phase structure, grain boundaries and grain orientation did not influence bacterial adherence or proliferation at microscale. Adherence of all four strains was similar on cp Ti and Ti 64 surfaces whilst inhibited on pure Al. This work establishes a nondestructive and straight-forward statistical method to analyse the relationship between microbial distribution and metal alloy structure. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  4. Composition quantification of electron-transparent samples by backscattered electron imaging in scanning electron microscopy.

    Science.gov (United States)

    Müller, E; Gerthsen, D

    2017-02-01

    The contrast of backscattered electron (BSE) images in scanning electron microscopy (SEM) depends on material parameters which can be exploited for composition quantification if some information on the material system is available. As an example, the In-concentration in thin In x Ga 1-x As layers embedded in a GaAs matrix is analyzed in this work. The spatial resolution of the technique is improved by using thin electron-transparent specimens instead of bulk samples. Although the BSEs are detected in a comparably small angular range by an annular semiconductor detector, the image intensity can be evaluated to determine the composition and local thickness of the specimen. The measured intensities are calibrated within one single image to eliminate the influence of the detection and amplification system. Quantification is performed by comparison of experimental and calculated data. Instead of using time-consuming Monte-Carlo simulations, an analytical model is applied for BSE-intensity calculations which considers single electron scattering and electron diffusion. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. 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...... the requirements for analysis of these films. High‐resolution electron backscatter diffraction is inadequate for full characterization of nanotwins, but image quality maps obtained from electron backscatter diffraction at least yield a qualitative estimation of the location and number of nanotwins. Complementing...... EBSD data based on ion channelling images are proposed. Thorough selection of the complementary techniques opens future perspectives for the investigation of other challenging samples with nanoscale features in the microstructure....

  6. A simple way to obtain backscattered electron images in a scanning transmission electron microscope.

    Science.gov (United States)

    Tsuruta, Hiroki; Tanaka, Shigeyasu; Tanji, Takayoshi; Morita, Chiaki

    2014-08-01

    We have fabricated a simple detector for backscattered electrons (BSEs) and incorporated the detector into a scanning transmission electron microscope (STEM) sample holder. Our detector was made from a 4-mm(2) Si chip. The fabrication procedure was easy, and similar to a standard transmission electron microscopy (TEM) sample thinning process based on ion milling. A TEM grid containing particle objects was fixed to the detector with a silver paste. Observations were carried out using samples of Au and latex particles at 75 and 200 kV. Such a detector provides an easy way to obtain BSE images in an STEM. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Characterization of Damage in Magnesium Using Digital Image Correlation and Electron Backscattered Diffraction Patterning

    Science.gov (United States)

    Nemcko, Michael J.; Mas, Pauline; Bruhis, Moisei; Wilkinson, David S.

    The microscopic strain distribution of commercially pure magnesium has been investigated during room temperature deformation. Digital image correlation (DIC) coupled with electron backscattered diffraction (EBSD) patterning has been used to relate strain measurements with the microstructure. Sheet magnesium tensile samples were etched and a random pattern of points were machined onto the sample surface using a focused ion beam (FIB). The samples were pulled in tension under an optical microscope. Images were obtained in increments and the DIC method was used to calculate the strain distribution. The strain distribution was compared to the EBSD pattern and the results show that strain localization is associated with twin and grain boundaries.

  8. False colour backscatter electron images and their application during electron microprobe analysis of ores and host rocks

    International Nuclear Information System (INIS)

    Cousens, D.R.; French, D.H.; Ramsden, A.R.

    1989-01-01

    The limited contrast range of conventional black and white imaging does not enable full use to be made of the dynamic range of the video signal obtained from a scanning electron microscope or microprobe. The use of false colour substantially increases the information that can be derived from such images enabling relationships to be displayed that cannot be observed in black and white. This capability is now used extensively in combination with quantitative electron microprobe analysis as a research tool for ore characterization and host rocks studies related to minerals exploration in the CSIRO Div.sion of Exploration Geoscience. Thus the CAMEBAX scanning electron microprobe has been modified to allow digital images acquisition and software (IMAGE) developed which allows false colour backscatter electron (BSE) images to be obtained during the course of routine electron microprobe analysis. 1 fig

  9. Point-spread functions for backscattered imaging in the scanning electron microscope

    Science.gov (United States)

    Hennig, Philipp; Denk, Winfried

    2007-12-01

    One knows the imaging system's properties are central to the correct interpretation of any image. In a scanning electron microscope regions of different composition generally interact in a highly nonlinear way during signal generation. Using Monte Carlo simulations we found that in resin-embedded, heavy metal-stained biological specimens staining is sufficiently dilute to allow an approximately linear treatment. We then mapped point-spread functions for backscattered-electron contrast, for primary energies of 3 and 7 keV and for different detector specifications. The point-spread functions are surprisingly well confined (both laterally and in depth) compared even to the distribution of only those scattered electrons that leave the sample again.

  10. Application of backscatter electrons for large area imaging of cavities produced by neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Pastukhov, V.I. [Joint Stock Company “Institute of Nuclear Materials” (JSC “INM”), Zarechny, Sverdlovsk Region (Russian Federation); Ural Federal University Named After the First President of Russia, B. N. Yeltsyn, Ekaterinburg (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation); Averin, S.A.; Panchenko, V.L. [Joint Stock Company “Institute of Nuclear Materials” (JSC “INM”), Zarechny, Sverdlovsk Region (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation); Portnykh, I.A. [Joint Stock Company “Institute of Nuclear Materials” (JSC “INM”), Zarechny, Sverdlovsk Region (Russian Federation); Freyer, P.D. [Westinghouse Electric Company, Pittsburgh, PA (United States); Giannuzzi, L.A. [L.A. Giannuzzi & Associates LLC, Fort Myers, FL (United States); Garner, F.A., E-mail: frank.garner@dslextreme.com [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation); Radiation Effects Consulting LLC, Richland, WA (United States); Texas A& M University, College Station, TX (United States)

    2016-11-15

    It is shown that with proper optimization, backscattered electrons in a scanning electron microscope can produce images of cavity distribution in austenitic steels over a large specimen surface for a depth of ∼500–700 nm, eliminating the need for electropolishing or multiple specimen production. This technique is especially useful for quantifying cavity structures when the specimen is known or suspected to contain very heterogeneous distributions of cavities. Examples are shown for cold-worked EK-164, a very heterogeneously-swelling Russian fast reactor fuel cladding steel and also for AISI 304, a homogeneously-swelling Western steel used for major structural components of light water cooled reactors. This non-destructive overview method of quantifying cavity distribution can be used to direct the location and number of required focused ion beam prepared transmission electron microscopy specimens for examination of either neutron or ion-irradiated specimens. This technique can also be applied in stereo mode to quantify the depth dependence of cavity distributions.

  11. Can X-ray spectrum imaging replace backscattered electrons for compositional contrast in the scanning electron microscope?

    Science.gov (United States)

    Newbury, Dale E; Ritchie, Nicholas W M

    2011-01-01

    The high throughput of the silicon drift detector energy dispersive X-ray spectrometer (SDD-EDS) enables X-ray spectrum imaging (XSI) in the scanning electron microscope to be performed in frame times of 10-100 s, the typical time needed to record a high-quality backscattered electron (BSE) image. These short-duration XSIs can reveal all elements, except H, He, and Li, present as major constituents, defined as 0.1 mass fraction (10 wt%) or higher, as well as minor constituents in the range 0.01-0.1 mass fraction, depending on the particular composition and possible interferences. Although BSEs have a greater abundance by a factor of 100 compared with characteristic X-rays, the strong compositional contrast in element-specific X-ray maps enables XSI mapping to compete with BSE imaging to reveal compositional features. Differences in the fraction of the interaction volume sampled by the BSE and X-ray signals lead to more delocalization of the X-ray signal at abrupt compositional boundaries, resulting in poorer spatial resolution. Improved resolution in X-ray elemental maps occurs for the case of a small feature composed of intermediate to high atomic number elements embedded in a matrix of lower atomic number elements. XSI imaging strongly complements BSE imaging, and the SDD-EDS technology enables an efficient combined BSE-XSI measurement strategy that maximizes the compositional information. If 10 s or more are available for the measurement of an area of interest, the analyst should always record the combined BSE-XSI information to gain the advantages of both measures of compositional contrast. Copyright © 2011 Wiley Periodicals, Inc.

  12. High-efficiency detector of secondary and backscattered electrons for low-dose imaging in the ESEM.

    Science.gov (United States)

    Neděla, Vilém; Tihlaříková, Eva; Runštuk, Jiří; Hudec, Jiří

    2018-01-01

    A new Combined System for high-efficiency detection of Secondary and Backscattered Electrons (CSSBE) in the ESEM consists of three detectors: an ionisation SE detector, an improved scintillation BSE detector, and a new Ionisation Secondary Electron Detector with an electrostatic Separator (ISEDS). The ISEDS optimizes conditions for electron-gas ionisation phenomena in the ESEM to achieve a strongly amplified signal from the secondary electrons with a minimal contribution from backscattered and beam electrons. For this purpose, it is originally equipped with an electrostatic separator, which focuses signal electrons towards a detection electrode and controls the concentration of positive ions above the sample. The working principle of the ISEDS is explained by simulations of signal electron trajectories in gas using the EOD program with our Monte Carlo module. The ability to detect the signal electrons in a selected range of energies is described with Geant4 Monte Carlo simulations of electron-solid interactions and proven by experimental results. High-efficiency detection of the ISEDS is demonstrated by imaging a low atomic number sample under a reduced beam energy of 5 keV, very low beam currents of up to 0.2 pA, and gas pressure of hundreds of Pa. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. 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.

  14. Analytical purpose electron backscattering system

    International Nuclear Information System (INIS)

    Desdin, L.; Padron, I.; Laria, J.

    1996-01-01

    In this work an analytical purposes electron backscattering system improved at the Center of Applied Studies for Nuclear Development is described. This system can be applied for fast, exact and nondestructive testing of binary and AL/Cu, AL/Ni in alloys and for other applications

  15. Dark-field imaging based on post-processed electron backscatter diffraction patterns of bulk crystalline materials in a scanning electron microscope.

    Science.gov (United States)

    Brodusch, Nicolas; Demers, Hendrix; Gauvin, Raynald

    2015-01-01

    Dark-field (DF) images were acquired in the scanning electron microscope with an offline procedure based on electron backscatter diffraction (EBSD) patterns (EBSPs). These EBSD-DF images were generated by selecting a particular reflection on the electron backscatter diffraction pattern and by reporting the intensity of one or several pixels around this point at each pixel of the EBSD-DF image. Unlike previous studies, the diffraction information of the sample is the basis of the final image contrast with a pixel scale resolution at the EBSP providing DF imaging in the scanning electron microscope. The offline facility of this technique permits the selection of any diffraction condition available in the diffraction pattern and displaying the corresponding image. The high number of diffraction-based images available allows a better monitoring of deformation structures compared to electron channeling contrast imaging (ECCI) which is generally limited to a few images of the same area. This technique was applied to steel and iron specimens and showed its high capability in describing more rigorously the deformation structures around micro-hardness indents. Due to the offline relation between the reference EBSP and the EBSD-DF images, this new technique will undoubtedly greatly improve our knowledge of deformation mechanism and help to improve our understanding of the ECCI contrast mechanisms. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Characterization of the thickness and distribution of latex coatings on polyvinylidene chloride beads by backscattered electron imaging.

    Science.gov (United States)

    Todd, Clifford S; Beyer, Douglas E

    2015-04-01

    Polyvinylidene chloride (PVDC) co-polymer resins are commonly formulated with a variety of solid additives for the purpose of processing or stabilization. A homogeneous distribution of these additives during handling and processing is important. The Dow Chemical Company developed a process to incorporate solid materials in latex form onto PVDC resin bead surfaces using a coagulation process. In this context, we present a method to characterize the distribution and thickness of these latex coatings. The difference in backscattered electron signal from the higher mean atomic number PVDC core and lower atomic number latex coating in conjunction with scanning electron microscopy (SEM) imaging using a range of accelerating voltages was used to characterize latex thickness and distribution across large numbers of beads quickly and easily. Monte Carlo simulations were used to quantitatively estimate latex thickness as a function of brightness in backscatter electron images. This thickness calibration was validated by cross-sectioning using a focused ion-beam SEM. Thicknesses from 100 nm up to about 1.3 µm can be determined using this method.

  17. Electron backscattering for process control in electron beam welding

    International Nuclear Information System (INIS)

    Ardenne, T. von; Panzer, S.

    1983-01-01

    A number of solutions to the automation of electron beam welding is presented. On the basis of electron backscattering a complex system of process control has been developed. It allows an enlarged imaging of the material's surface, improved adjustment of the beam focusing and definite focus positioning. Furthermore, both manual and automated positioning of the electron beam before and during the welding process has become possible. Monitoring of the welding process for meeting standard welding requirements can be achieved with the aid of a control quantity derived from the results of electronic evaluation of the high-frequency electron backscattering

  18. Detection of secondary and backscattered electrons for 3D imaging with multi-detector method in VP/ESEM.

    Science.gov (United States)

    Slówko, Witold; Wiatrowski, Artur; Krysztof, Michał

    2018-01-01

    The paper considers some major problems of adapting the multi-detector method for three-dimensional (3D) imaging of wet bio-medical samples in Variable Pressure/Environmental Scanning Electron Microscope (VP/ESEM). The described method pertains to "single-view techniques", which to create the 3D surface model utilise a sequence of 2D SEM images captured from a single view point (along the electron beam axis) but illuminated from four directions. The basis of the method and requirements resulting from them are given for the detector systems of secondary (SE) and backscattered electrons (BSE), as well as designs of the systems which could work in variable conditions. The problems of SE detection with application of the Pressure Limiting Aperture (PLA) as the signal collector are discussed with respect to secondary electron backscattering by a gaseous environment. However, the authors' attention is turned mainly to the directional BSE detection, realized in two ways. The high take off angle BSE were captured through PLA with use of the quadruple semiconductor detector placed inside the intermediate chamber, while BSE starting at lower angles were detected by the four-folded ionization device working in the sample chamber environment. The latter relied on a conversion of highly energetic BSE into low energetic SE generated on walls and a gaseous environment of the deep discharge gap oriented along the BSE velocity direction. The converted BSE signal was amplified in an ionising avalanche developed in the electric field arranged transversally to the gap. The detector system operation is illustrated with numerous computer simulations and examples of experiments and 3D images. The latter were conducted in a JSM 840 microscope with its combined detector-vacuum equipment which could extend capabilities of this high vacuum instrument toward elevated pressures (over 1kPa) and environmental conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Three-dimensional cathodoluminescence imaging and electron backscatter diffraction: tools for studying the genetic nature of diamond inclusions

    NARCIS (Netherlands)

    Wiggers de Vries, D.F.; Drury, M.R.; Winter, D.A.M.; Bulanova, G.P.; Pearson, D.G.; Davies, G.R.

    2011-01-01

    As a step towards resolving the genesis of inclusions in diamonds, a new technique is presented. This technique combines cathodoluminescence (CL) and electron backscatter diffraction (EBSD) using a focused ion beam-scanning electron microscope (FIB-SEM) instrument with the aim of determining, in

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

    Directory of Open Access Journals (Sweden)

    A Boyde

    2012-07-01

    Full Text Available 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.

  1. Contribution of backscattered electrons to the total electron yield ...

    Indian Academy of Sciences (India)

    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 ...

  2. Use of backscattered electron imaging, X-ray microanalysis and X-ray microscopy in demonstrating physiological cell death

    International Nuclear Information System (INIS)

    Bowen, I.D.; Worrill, N.A.; Winters, C.A.; Mullarkey, K.

    1988-01-01

    The cytochemical localization of enzymatic activity by means of backscattered electron imaging (BEI) is reviewed and the application of BEI to changes in acid phosphatase and ATPase distribution during physiological (programmed) cell death in Heliothis midgut is explored. Programmed cell death entails the release of nascent free acid phosphatase as extracisternal hydrolase. This shift can readily be detected by means of the atomic number contrast imparted by BEI of the lead phosphatase reaction product, thus enabling the distribution of dying cells to be mapped. BEI is particularly useful in this context as it allows the examination of bulk specimens at low magnification. Death of cells is also accompanied by a collapse in ATPase activity which shows up as cytochemically negative areas in the X-ray microscope and by means of BEI. Acid phosphatase in normal cells is localized in the apical microvilli and lysosomes. Senescent or dying cells, however, clearly show a basally situated free hydrolase which migrates throughout the cell. Parallel TEM results confirm that this enzyme is ribosomal and extracisternal rather than lysosomal in origin. ATPase activity is largely limited to the apical microvilli, although there is some activity associated with the basal plasma membranes. The apical ATPase, however is partially resistant to ouabain. Young and mature cells are positive although in the latter case some microvilli may be lost as the cells acquire a negative cap or dome. Inhibition by bromotetramizole indicates that apical activity is not to any significant extent contributed to by alkaline phosphatase. Degenerate or dead cells are negative and can be seen as a mozaic of black patches among normal cells when imaged by means of BEI or X-ray microscopy

  3. Analytical expressions for the electron backscattering coefficient

    International Nuclear Information System (INIS)

    August, H.J.; Wernisch, J.

    1989-01-01

    Several analytical expressions for the electron backscattering coefficient for massive homogeneous samples are compared with experimental data, directing special attention to the dependence of this quantity on the electron acceleration energy. It is shown that this dependence generally cannot be neglected. The expression proposed by Hunger and Kuechler turns out to be better than that of Love and Scott, although even the better formula can be slightly improved by a small modification. (author)

  4. Simulation of ultrasound backscatter images from fish

    DEFF Research Database (Denmark)

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

    2011-01-01

    The objective of this work is to investigate ultrasound (US) backscatter in the MHz range from fis to develop a realistic and reliable simulation model. The long term objective of the work is to develop the needed signal processing for fis species differentiation using US. In in-vitro experiments...... images reproduce most of the important characteristics of the measured US image....

  5. Energy and angular distributions of backscattered electrons from ...

    Indian Academy of Sciences (India)

    Abstract. 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 EB = 50 eV and 5000. eV. The angle of incidence α and take-off angle θ are ...

  6. Energy and angular distributions of backscattered electrons from ...

    Indian Academy of Sciences (India)

    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 ...

  7. TU-E-BRA-02: A Method to Remove Support Arm Backscatter from EPID Images.

    Science.gov (United States)

    King, B; Greer, P

    2012-06-01

    To develop a method for removing the effect of support arm backscatter from Varian electronic portal imaging devices (EPIDs), improving the dosimetric abilities of the imager. A physical, kernel based model of the backscatter signal produced during an exposure was developed. The model parameters were determined through an optimization process, comparing measured images without arm backscatter (EPID removed from arm) to measured images that include arm backscatter. The backscatter model was used to develop a backscatter correction process that removes the support arm backscatter from measured EPID images. The correction process was tested by applying the method to measured images of 17 rectangular asymmetric fields and comparing the Result to off-arm images. The same process was repeated with 42 IMRT fields. The backscatter removal process was able to effectively remove the arm backscatter from all of the measured images and accurately predict the measured off-arm images. Comparing the corrected images to the measured off-arm images, the mean absolute difference at the centre of each rectangular field was 0.29% (standard deviation 0.18%). This is an improvement over the uncorrected images which gave a mean difference of 1.01% (standard deviation 0.73%). The largest discrepancy observed with the corrected images was 0.6%, compared to 2.8% for the uncorrected images. Comparing the corrected IMRT images to the measured off-arm images, an overall mean gamma value of 0.28 (standard deviation 0.04) was found using 2%, 2mm criteria. Comparison of the uncorrected images to the measured off-arm images resulted in an overall mean gamma of 0.40 (standard deviation 0.10). A method for accurately and reliably removing the effect of support arm backscatter from EPID images has been developed and extensively tested. The method can be applied to any measured EPID image and does not require any additional information about the exposure. © 2012 American Association of Physicists in

  8. Ultrastructural study by backscattered electron imaging and elemental microanalysis of bone-to-biomaterial interface and mineral degradation of porcine xenografts used in maxillary sinus floor elevation.

    Science.gov (United States)

    Ramírez-Fernández, Maria Piedad; Calvo-Guirado, Jose Luis; Maté-Sánchez Del Val, Jose Eduardo; Delgado-Ruiz, Rafael Arcesio; Negri, Bruno; Barona-Dorado, Cristina

    2013-05-01

    The aim of this study was to carry out an ultrastructural study of the biomaterial-to-bone interface and biomaterial mineral degradation in retrieved bone biopsies following maxillary sinus augmentation using collagenized porcine xenografts (Osteobiol(®) Mp3) in 15 clinical cases. Nine months after sinus lifting, bone cores were harvested from the maxillary sinus. The specimens were processed for observation under a scanning electron microscope with backscattered electron imaging (SEM-BSE). In addition, chemical analysis and elemental mapping of the mineral composition were generated using a microanalytical system based on energy-dispersive X-ray spectrometry (EDX). No clinical complications were evident during surgery. Scanning electron microscopy revealed that newly formed bone had become closely attached to the xenograft. Statistical analysis showed a significantly high Ca/P ratio in the biomaterial (2.46 ± 0.16) and at the bone interface (2.00 ± 0.48) compared to bone (1.97 ± 0.36), which suggests that there may be a gradual diffusion of Ca ions from the biomaterial into the newly forming bone at the interface as part of the biomaterial's resorption process. EDX analysis of the residual porcine biomaterial at different points showed some particle categories with different mean ratios of Ca/P according to size, pointing to different stages of the resorption process. The biomaterial proved to be biocompatible, bioreabsorbable and osteoconductive when used as a bone substitute for maxillary sinus elevation. SEM-BSE revealed that newly formed bone had become closely attached to the xenografts. EDX analysis monitored the resorption process of the porcine bone xenograft. Elemental mapping showed that there was a gradual diffusion of Ca ions from the biomaterial to the newly forming bone at the interface. © 2012 John Wiley & Sons A/S.

  9. Principles of electron backscattering by solids and thin films

    International Nuclear Information System (INIS)

    Niedrig, H.

    1977-01-01

    The parameters concerning the electron backscattering from thin films and solids (atomic scattering cross-section, atomic number, single/multiple scattering, film thickness of self-supporting films and of surface films on bulk substrates, scattering angular distribution, angle of incidence, diffraction effects) are described. Their influence on some important contrast mechanisms in scanning electron microscopy (thickness contrast, Z/material contrast, tilting/topography contrast, orientation contrast) is discussed. The main backscattering electron detection systems are briefly described. (orig.) [de

  10. Implementing Transmission Electron Backscatter Diffraction for Atom Probe Tomography.

    Science.gov (United States)

    Rice, Katherine P; Chen, Yimeng; Prosa, Ty J; Larson, David J

    2016-06-01

    There are advantages to performing transmission electron backscattering diffraction (tEBSD) in conjunction with focused ion beam-based specimen preparation for atom probe tomography (APT). Although tEBSD allows users to identify the position and character of grain boundaries, which can then be combined with APT to provide full chemical and orientation characterization of grain boundaries, tEBSD can also provide imaging information that improves the APT specimen preparation process by insuring proper placement of the targeted grain boundary within an APT specimen. In this report we discuss sample tilt angles, ion beam milling energies, and other considerations to optimize Kikuchi diffraction pattern quality for the APT specimen geometry. Coordinated specimen preparation and analysis of a grain boundary in a Ni-based Inconel 600 alloy is used to illustrate the approach revealing a 50° misorientation and trace element segregation to the grain boundary.

  11. Validation Test of Geant4 Simulation of Electron Backscattering

    CERN Document Server

    Kim, Sung Hun; Basaglia, Tullio; Han, Min Cheol; Hoff, Gabriela; Kim, Chan Hyeong; Saracco, Paolo

    2015-01-01

    Backscattering is a sensitive probe of the accuracy of electron scattering algorithms implemented in Monte Carlo codes. The capability of the Geant4 toolkit to describe realistically the fraction of electrons backscattered from a target volume is extensively and quantitatively evaluated in comparison with experimental data retrieved from the literature. The validation test covers the energy range between approximately 100 eV and 20 MeV, and concerns a wide set of target elements. Multiple and single electron scattering models implemented in Geant4, as well as preassembled selections of physics models distributed within Geant4, are analyzed with statistical methods. The evaluations concern Geant4 versions from 9.1 to 10.1. Significant evolutions are observed over the range of Geant4 versions, not always in the direction of better compatibility with experiment. Goodness-of-fit tests complemented by categorical analysis tests identify a configuration based on Geant4 Urban multiple scattering model in Geant4 vers...

  12. Method and Apparatus for Computed Imaging Backscatter Radiography

    Science.gov (United States)

    Shedlock, Daniel (Inventor); Meng, Christopher (Inventor); Sabri, Nissia (Inventor); Dugan, Edward T. (Inventor); Jacobs, Alan M. (Inventor)

    2013-01-01

    Systems and methods of x-ray backscatter radiography are provided. A single-sided, non-destructive imaging technique utilizing x-ray radiation to image subsurface features is disclosed, capable of scanning a region using a fan beam aperture and gathering data using rotational motion.

  13. Application of electron back-scatter diffraction to texture research

    International Nuclear Information System (INIS)

    Randle, V.

    1996-01-01

    The application of electron back-scatter diffraction (EBSD) to materials research is reviewed. A brief history of the technique is given, followed by a description of present-day operation. The methodology of 'microtexture', i.e. spatially specific orientations, is described and recent examples of its application using EBSD are given, in particular to interstitial-free steel processing, growth of phases in a white iron and grain boundary phenomena in a superplastic alloy. The advantages and disadvantages of EBSD compared to use of X-rays for texture determination are discussed in detail

  14. Simulation of the backscattered electron intensity of multi layer structure for the explanation of secondary electron contrast

    Energy Technology Data Exchange (ETDEWEB)

    Sulyok, A.; Toth, A.L. [Research Institute for Technical Physics and Materials Science, Budapest H-1525, P.O. Box 49 (Hungary); Zommer, L., E-mail: lzommer@ichf.edu.pl [Polish Academy of Sciences, Institute of Physical Chemistry, ul. Kasprzaka 44/52, 01-224 Warsaw (Poland); Menyhard, M. [Research Institute for Technical Physics and Materials Science, Budapest H-1525, P.O. Box 49 (Hungary); Jablonski, A. [Polish Academy of Sciences, Institute of Physical Chemistry, ul. Kasprzaka 44/52, 01-224 Warsaw (Poland)

    2013-01-15

    The intensities of the secondary electrons (SE) and of the backscattered electrons (BSE) at energy 100 eV have been measured on a Ni/C/Ni/C/Ni/C/(Si substrate) multilayer structure by exciting it with primary electrons of 5, 2.5 and 1.25 keV energies. It has been found that both intensities similarly vary while thinning the specimen. The difference as small as 4 nm in the underlying layer thicknesses resulted in visible intensity change. Utilizing this intensity change, the thickness difference of neighboring regions could be revealed from the SE image. No simple phenomenological model was found to interpret the change of intensity, thus the intensity of the BSE electrons has been calculated by means of a newly developed Monte Carlo simulation. This code also considers the secondary electron generation and transport through the solid. The calculated and measured intensities agree well supporting the validity of the model. -- Highlights: Black-Right-Pointing-Pointer similarities in scanning electron microscopy and backscattered electrons were used. Black-Right-Pointing-Pointer MC algorithm for sample made from metal and semiconductor layers was workout. Black-Right-Pointing-Pointer electron backscattering depth dependence resembles Auger depth profiling curves.

  15. Application of Electron Backscatter Diffraction to Phase Identification

    Energy Technology Data Exchange (ETDEWEB)

    El-Dasher, B S; Deal, A

    2008-07-16

    The identification of crystalline phases in solids requires knowledge of two microstructural properties: crystallographic structure and chemical composition. Traditionally, this has been accomplished using X-ray diffraction techniques where the measured crystallographic information, in combination with separate chemical composition measurements for specimens of unknown pedigrees, is used to deduce the unknown phases. With the latest microstructural analysis tools for scanning electron microscopes, both the crystallography and composition can be determined in a single analysis utilizing electron backscatter diffraction and energy dispersive spectroscopy, respectively. In this chapter, we discuss the approach required to perform these experiments, elucidate the benefits and limitations of this technique, and detail via case studies how composition, crystallography, and diffraction contrast can be used as phase discriminators.

  16. Automated determination of crystal orientations from electron backscattering patterns

    DEFF Research Database (Denmark)

    Lassen, Niels Christian Krieger

    1994-01-01

    these calibration parameters can be estimated with high precision. The quality of EBSPs provides important information about the reliability of the measured crystal orientations and about the perfection of the lattice in which the pattern is generated. A measure which allows the quality of EBSPs to be evaluated......The electron backscattering pattern (EBSP) technique is widely accepted as being an extremely powerful tool for measuring the crystallographic orientation of individual crystallites in polycrystalline materials. Procedures which allow crystal orientations to be calculated on the bases...... of a pattern recognition procedure which enables 8 to 12 bands to be localized in typical EBSPs from a modern system. It will be described, how these automatically localized bands can be indexed and used for optimal estimation of the unknown crystal orientations. A necessary prerequisite for precise...

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

    International Nuclear Information System (INIS)

    Randle, Valerie

    2009-01-01

    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.

  18. Contribution of backscattered electrons to the total electron yield ...

    Indian Academy of Sciences (India)

    Hunger and Kuchler [21] have also made a theoretical study of this variation in the range of 4–40 keV. The curve shown in the figure is the prediction of their theoretical calculations which is found to be in a good agreement with our experimental data. For studying the behavior of electrons penetrating a solid target, there are ...

  19. Angle selective backscattered electron contrast in the low-voltage scanning electron microscope: Simulation and experiment for polymers

    Energy Technology Data Exchange (ETDEWEB)

    Wan, Q., E-mail: qwan2@sheffield.ac.uk [Department of Material Science and Engineering, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom); Masters, R.C. [Department of Material Science and Engineering, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom); Lidzey, D. [Department of Physics and Astronomy, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom); Abrams, K.J. [Department of Material Science and Engineering, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom); Dapor, M. [European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT-FBK) and Trento Institute for Fundamental Physics and Applications (TIFPA-INFN), via Sommarive 18, I-38123 Trento (Italy); Plenderleith, R.A. [Department of Material Science and Engineering, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom); Rimmer, S. [Department of Chemistry, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom); Claeyssens, F.; Rodenburg, C. [Department of Material Science and Engineering, University of Sheffield, Western Bank, Sheffield S10 2TN (United Kingdom)

    2016-12-15

    Recently developed detectors can deliver high resolution and high contrast images of nanostructured carbon based materials in low voltage scanning electron microscopes (LVSEM) with beam deceleration. Monte Carlo Simulations are also used to predict under which exact imaging conditions purely compositional contrast can be obtained and optimised. This allows the prediction of the electron signal intensity in angle selective conditions for back-scattered electron (BSE) imaging in LVSEM and compares it to experimental signals. Angle selective detection with a concentric back scattered (CBS) detector is considered in the model in the absence and presence of a deceleration field, respectively. The validity of the model prediction for both cases was tested experimentally for amorphous C and Cu and applied to complex nanostructured carbon based materials, namely a Poly(N-isopropylacrylamide)/Poly(ethylene glycol) Diacrylate (PNIPAM/PEGDA) semi-interpenetration network (IPN) and a Poly(3-hexylthiophene-2,5-diyl) (P3HT) film, to map nano-scale composition and crystallinity distribution by avoiding experimental imaging conditions that lead to a mixed topographical and compositional contrast - Highlights: • An optimised model for nano-scale analysis of beam sensitive materials by LVSEM. • Simulation and separation of composition and topography in a CBS detector. • Selective angle backscattered electron collection for mapping of polymers.

  20. A Dictionary Approach to Electron Backscatter Diffraction Indexing.

    Science.gov (United States)

    Chen, Yu H; Park, Se Un; Wei, Dennis; Newstadt, Greg; Jackson, Michael A; Simmons, Jeff P; De Graef, Marc; Hero, Alfred O

    2015-06-01

    We propose a framework for indexing of grain and subgrain structures in electron backscatter diffraction patterns of polycrystalline materials. We discretize the domain of a dynamical forward model onto a dense grid of orientations, producing a dictionary of patterns. For each measured pattern, we identify the most similar patterns in the dictionary, and identify boundaries, detect anomalies, and index crystal orientations. The statistical distribution of these closest matches is used in an unsupervised binary decision tree (DT) classifier to identify grain boundaries and anomalous regions. The DT classifies a pattern as an anomaly if it has an abnormally low similarity to any pattern in the dictionary. It classifies a pixel as being near a grain boundary if the highly ranked patterns in the dictionary differ significantly over the pixel's neighborhood. Indexing is accomplished by computing the mean orientation of the closest matches to each pattern. The mean orientation is estimated using a maximum likelihood approach that models the orientation distribution as a mixture of Von Mises-Fisher distributions over the quaternionic three sphere. The proposed dictionary matching approach permits segmentation, anomaly detection, and indexing to be performed in a unified manner with the additional benefit of uncertainty quantification.

  1. Orientation effects on indexing of electron backscatter diffraction patterns

    International Nuclear Information System (INIS)

    Nowell, Matthew M.; Wright, Stuart I.

    2005-01-01

    Automated Electron Backscatter Diffraction (EBSD) has become a well-accepted technique for characterizing the crystallographic orientation aspects of polycrystalline microstructures. At the advent of this technique, it was observed that patterns obtained from grains in certain crystallographic orientations were more difficult for the automated indexing algorithms to accurately identify than patterns from other orientations. The origin of this problem is often similarities between the EBSD pattern of the correct orientation and patterns from other orientations or phases. While practical solutions have been found and implemented, the identification of these problem orientations generally occurs only after running an automated scan, as problem orientations are often readily apparent in the resulting orientation maps. However, such an approach only finds those problem orientations that are present in the scan area. It would be advantageous to identify all regions of orientation space that may present problems for automated indexing prior to initiating an automated scan, and to minimize this space through the optimization of acquisition and indexing parameters. This work presents new methods for identifying regions in orientation space where the reliability of the automated indexing is suspect prior to performing a scan. This methodology is used to characterize the impact of various parameters on the indexing algorithm

  2. Reconstruction of chalk pore networks from 2D backscatter electron micrographs using a simulated annealing technique

    Energy Technology Data Exchange (ETDEWEB)

    Talukdar, M.S.; Torsaeter, O. [Department of Petroleum Engineering and Applied Geophysics, Norwegian University of Science and Technology, Trondheim (Norway)

    2002-05-01

    We report the stochastic reconstruction of chalk pore networks from limited morphological information that may be readily extracted from 2D backscatter electron (BSE) images of the pore space. The reconstruction technique employs a simulated annealing (SA) algorithm, which can be constrained by an arbitrary number of morphological descriptors. Backscatter electron images of a high-porosity North Sea chalk sample are analyzed and the morphological descriptors of the pore space are determined. The morphological descriptors considered are the void-phase two-point probability function and lineal path function computed with or without the application of periodic boundary conditions (PBC). 2D and 3D samples have been reconstructed with different combinations of the descriptors and the reconstructed pore networks have been analyzed quantitatively to evaluate the quality of reconstructions. The results demonstrate that simulated annealing technique may be used to reconstruct chalk pore networks with reasonable accuracy using the void-phase two-point probability function and/or void-phase lineal path function. Void-phase two-point probability function produces slightly better reconstruction than the void-phase lineal path function. Imposing void-phase lineal path function results in slight improvement over what is achieved by using the void-phase two-point probability function as the only constraint. Application of periodic boundary conditions appears to be not critically important when reasonably large samples are reconstructed.

  3. 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.

    Using the rms (root mean square) backscatter amplitude values, a procedure was evolved to generate pseudo sidescan images. A comparison of the pseudo sidescan image with actual Hydrosweep sidescan image, from an area covering a pear shaped seamount...

  4. Evaluation of the photon monitor backscatter in medical electron accelerators

    International Nuclear Information System (INIS)

    Zrenner, M.; Krieger, H.

    1999-01-01

    Background: Modern linear accelerators permit the use of irregular fields due to their flexible collimator systems with separately movable jaws or multileaf collimators. When using such irregular fields in the clinical practice output factors have to be corrected for enhanced backscatter to the dose monitor as compared with the conventional block shieldings. Methods: A method is presented to detect the monitor backscatter contributions to the output factor for irregular field settings. Results: The monitor backscatter factors have been measured using a telescopic device for 2 different treatment head geometries (Varian Clinac 2100C/D, General Electric Saturne 15) and for 3 photon radiation qualities (nominal energies X6, X18, X12). A method is introduced to calculate the monitor backscatter for arbitrary irregular treatment fields from the experimental data for square or rectangular fields. Conclusions: Besides the corrections for changes in phantom scatter and changes in the aperture, corrections for monitor backscatter have to be taken into account in many clinical cases. They can contribute up to more than 10% compared with the monitor values for free regular fields. (orig.) [de

  5. A multislice theory of electron scattering in crystals including backscattering and inelastic effects.

    Science.gov (United States)

    Spiegelberg, Jakob; Rusz, Ján

    2015-12-01

    In the framework of the slice transition operator technique, a general multislice theory for electron scattering in crystals is developed. To achieve this generalization, we combine the approaches for inelastic scattering derived by Yoshioka [J. Phys. Soc. Jpn. 12, 6 (1957)] and backscattering based on the formalism of Chen and Van Dyck [Ultramicroscopy 70, 29-44 (1997)]. A computational realization of the obtained equations is suggested. The proposed computational scheme is tested on elastic backscattering of electrons, where we consider single backscattering in analogy to the computational scheme proposed by Chen and Van Dyck. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Lattice constant measurement from electron backscatter diffraction patterns

    DEFF Research Database (Denmark)

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

    2017-01-01

    Kikuchi bands in election backscattered diffraction patterns (EBSP) contain information about lattice constants of crystallographic samples that can be extracted via the Bragg equation. An advantage of lattice constant measurement from EBSPs over diffraction (XRD) is the ability to perform local ...

  7. 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

  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)

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

    2015-01-01

    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

  9. 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

  10. Lattice constant measurement from electron backscatter diffraction patterns

    DEFF Research Database (Denmark)

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

    2017-01-01

    Kikuchi bands in election backscattered diffraction patterns (EBSP) contain information about lattice constants of crystallographic samples that can be extracted via the Bragg equation. An advantage of lattice constant measurement from EBSPs over diffraction (XRD) is the ability to perform local...... is approximately 0.04 Å. Studying Kikuchi band size dependence of the measurement precision shows that the measurement error decays with increasing band size (i.e. decreasing lattice constant). However, in practice, the sharpness of wide bands tends to be low due to their low intensity, thus limiting...

  11. Clean image synthesis and target numerical marching for optical imaging with backscattering light.

    Science.gov (United States)

    Xu, Min; Pu, Yang; Wang, Wubao

    2011-03-14

    Scanning backscattering imaging and independent component analysis (ICA) are used to probe targets hidden in the subsurface of a turbid medium. A new correction procedure is proposed and used to synthesize a "clean" image of a homogeneous host medium numerically from a set of raster-scanned "dirty" backscattering images of the medium with embedded targets. The independent intensity distributions on the surface of the medium corresponding to individual targets are then unmixed using ICA of the difference between the set of dirty images and the clean image. The target positions are localized by a novel analytical method, which marches the target to the surface of the turbid medium until a match with the retrieved independent component is accomplished. The unknown surface property of the turbid medium is automatically accounted for by this method. Employing clean image synthesis and target numerical marching, three-dimensional (3D) localization of objects embedded inside a turbid medium using independent component analysis in a backscattering geometry is demonstrated for the first time, using as an example, imaging a small piece of cancerous prostate tissue embedded in a host consisting of normal prostate tissue.

  12. Angle selective backscattered electron contrast in the low-voltage scanning electron microscope: Simulation and experiment for polymers.

    Science.gov (United States)

    Wan, Q; Masters, R C; Lidzey, D; Abrams, K J; Dapor, M; Plenderleith, R A; Rimmer, S; Claeyssens, F; Rodenburg, C

    2016-12-01

    Recently developed detectors can deliver high resolution and high contrast images of nanostructured carbon based materials in low voltage scanning electron microscopes (LVSEM) with beam deceleration. Monte Carlo Simulations are also used to predict under which exact imaging conditions purely compositional contrast can be obtained and optimised. This allows the prediction of the electron signal intensity in angle selective conditions for back-scattered electron (BSE) imaging in LVSEM and compares it to experimental signals. Angle selective detection with a concentric back scattered (CBS) detector is considered in the model in the absence and presence of a deceleration field, respectively. The validity of the model prediction for both cases was tested experimentally for amorphous C and Cu and applied to complex nanostructured carbon based materials, namely a Poly(N-isopropylacrylamide)/Poly(ethylene glycol) Diacrylate (PNIPAM/PEGDA) semi-interpenetration network (IPN) and a Poly(3-hexylthiophene-2,5-diyl) (P3HT) film, to map nano-scale composition and crystallinity distribution by avoiding experimental imaging conditions that lead to a mixed topographical and compositional contrast. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  13. 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. Published 2011. This article is a US Government work and is in the public domain in the USA.

  14. Surface excitations in electron backscattering from silicon surfaces

    Czech Academy of Sciences Publication Activity Database

    Zemek, Josef; Jiříček, Petr; Lesiak, B.; Jablonski, A.

    2004-01-01

    Roč. 562, - (2004), s. 92-100 ISSN 0039-6028 R&D Projects: GA ČR GA202/02/0237 Institutional research plan: CEZ:AV0Z1010914 Keywords : electron-solid interactions * electron-solid scattering and transmission-elastic * electron-solid scattering and transmission-inelastic * Monte Carlo simulation * electron bombardment * silicon Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.168, year: 2004

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

    International Nuclear Information System (INIS)

    Mortazavi, Halleh; Oakley, John P; Barkat, Braham

    2013-01-01

    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)

  16. Absorption and backscatter of internal conversion electrons in the measurements of surface contamination of 137Cs

    International Nuclear Information System (INIS)

    Yunoki, A.; Kawada, Y.; Yamada, T.; Unno, Y.; Sato, Y.; Hino, Y.

    2013-01-01

    We measured 4π and 2π counting efficiencies for internal conversion electrons (ICEs), gross β-particles and also β-rays alone with various source conditions regarding absorber and backing foil thickness using e-X coincidence technique. Dominant differences regarding the penetration, attenuation and backscattering properties among ICEs and β-rays were revealed. Although the abundance of internal conversion electrons of 137 Cs- 137 Ba is only 9.35%, 60% of gross counts may be attributed to ICEs in worse source conditions. This information will be useful for radionuclide metrology and for surface contamination monitoring. - Highlights: • Counting efficiencies for internal conversion electrons from 137 Cs were measured, and compared with those for β-rays. • Electron-X coincidence technique was employed. • A thin NaI(Tl) scintillation detector was used for X-ray detection. • Backscattering fractions of electrons and beta particles were studied by similar experiments

  17. Carbon/Hydrogen ratio determination in hydrocarbons and its mixtures by electron backscattering technique

    International Nuclear Information System (INIS)

    Padron, I.; Desdin, L.F.; Navarro, A.; Fuentes, M.

    1996-01-01

    A method carbon/hydrogen ratio (C/H) determination in hydrocarbons and its mixtures was improved using the electron backscattering technique. Besides the hetero atoms (S,O and N) influence in petroleum is studied for being able to determinate the C/H ratio in cuban petroleum with high sulphur contents

  18. Contribution of back-scattered electromagnetic rays to the Moessbauer conversion electron spectrum

    International Nuclear Information System (INIS)

    Ruskov, T.; Ruskov, R.; Paneva, D.; Lefterov, D.

    1999-01-01

    The contribution of back-scattered electromagnetic rays in a 57 Fe conversion electron Moessbauer spectrum is considered using proportional counter as a detector. A simplified method for measuring this contribution is described. The experimental results show that this contribution strongly depends on the construction of the counter and the selected fraction in the pulse-height spectrum

  19. Evaluation of backscatter dose from internal lead shielding in clinical electron beams using EGSnrc Monte Carlo simulations.

    Science.gov (United States)

    De Vries, Rowen J; Marsh, Steven

    2015-11-08

    Internal lead shielding is utilized during superficial electron beam treatments of the head and neck, such as lip carcinoma. Methods for predicting backscattered dose include the use of empirical equations or performing physical measurements. The accuracy of these empirical equations required verification for the local electron beams. In this study, a Monte Carlo model of a Siemens Artiste linac was developed for 6, 9, 12, and 15 MeV electron beams using the EGSnrc MC package. The model was verified against physical measurements to an accuracy of better than 2% and 2mm. Multiple MC simulations of lead interfaces at different depths, corresponding to mean electron energies in the range of 0.2-14 MeV at the interfaces, were performed to calculate electron backscatter values. The simulated electron backscatter was compared with current empirical equations to ascertain their accuracy. The major finding was that the current set of backscatter equations does not accurately predict electron backscatter, particularly in the lower energies region. A new equation was derived which enables estimation of electron backscatter factor at any depth upstream from the interface for the local treatment machines. The derived equation agreed to within 1.5% of the MC simulated electron backscatter at the lead interface and upstream positions. Verification of the equation was performed by comparing to measurements of the electron backscatter factor using Gafchromic EBT2 film. These results show a mean value of 0.997 ± 0.022 to 1σ of the predicted values of electron backscatter. The new empirical equation presented can accurately estimate electron backscatter factor from lead shielding in the range of 0.2 to 14 MeV for the local linacs.

  20. A preliminary electron backscattered diffraction study of sintered NdFeB-type magnets.

    Science.gov (United States)

    Lillywhite, S J; Williams, A J; Davies, B E; Harris, I R

    2002-03-01

    This paper reports, for the first time, the use of electron backscattered diffraction (EBSD) to study orientation in sintered NdFeB type magnets. The magnetic properties of NdFeB magnets are greatly improved if a strong crystallographic texture is firstly achieved, namely, the direction of the c-axis is along the direction of magnetization. A systematic survey of sample preparation techniques showed that samples that were mechanically polished and then etched gave the most reliable EBSD data. Analyses were made using both fully automated EBSD scans and by EBSD measurements taken after manual movement of the beam. The EBSD results are presented as secondary electron SEM micrographs, orientation images and 001 pole figures. For the selection of grains investigated, the deviation of the c-axis was shown to be between 10 degrees and 30 degrees from the ideal [001]//magnetization direction. It is demonstrated that EBSD is a valuable tool for characterizing the microstructure and texture relationships and for assessing the performance of the processing routes of NdFeB magnets.

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

    International Nuclear Information System (INIS)

    Shrestha, Sachin L.; Breen, Andrew J.; Trimby, Patrick; Proust, Gwénaëlle; Ringer, Simon P.; Cairney, Julie M.

    2014-01-01

    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

  2. Electronic Imaging

    Science.gov (United States)

    1997-10-01

    image blur, as in Fig. 5, is well suited to efficient and private data transmission and we describe the use of DPCM and DCT-based algorithms. For... DPCM compression, we find that the bit rates required in a Huffman code can be reduced up to 50% by using a multiple-point blur prefilter

  3. 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 ...

  4. 3D invariant embedding model for backscattering electrons applied to materials characterization

    International Nuclear Information System (INIS)

    Figueroa, C.; Nieva, N.; Heluani, S.P.

    2007-01-01

    In this work, the results of a 3D model used to describe the fraction of backscattered electrons, together with its energy and angular distributions, are reported. This 3D model is the result of improvements in the Invariant Embedding Approach to Microanalysis (IEAM). Comparisons with experiment show that the theoretical results follow the general trend of experimental data, when parameters (such as atomic number, energy of the impinging electrons and tilted angle) are changed

  5. Electron backscattering and secondary electron emission from carbon targets: comparison of experimental results with Monte Carlo simulations

    International Nuclear Information System (INIS)

    Farhang, H.; Blott, B.H.; Napchan, E.

    1993-01-01

    Electron backscattering (EBS) and secondary electron emission (SEE) yield have been measured for bulk carbon with a density of 1.8 g cm -3 , for primary electron energies in the range from 100 to 500 eV and from 12 to 1000 ev respectively. The backscattering results were in agreement with an empirical formula to within 2%. The SEE yield value was 0.04 at lowest measured energy (12 eV) and reached a maximum value of 0.54 at about 300 eV. The backscattering coefficients and SEE yield have also been calculated using a Monte Carlo simulation for the energy range from 12 to 1000 eV. In the simulation, two different energy loss characteristics were used. The first was obtained from a set of optical data and gave good agreement with the experiment SEE yield but poor agreement with the backscattering data. The second was obtained from a modified Bethe energy loss function which fitted the backscattering data well. Using the Bethe loss function for each primary electron, the SEE yield was calculated for every path length between scattering events by dividing the primary electron energy lost per unit path length by the average energy required to create a secondary electron. The SEE data was fitted on the assumption that the average energy to create a secondary varied with primary electron energy according to a four parameter function. Comparison of the calculated SEE yield with the experimental SEE yield, as a function of incident angle of the primary beam, was good over the energy range from 100 to 500 eV. (Author)

  6. Effects of fatty infiltration in human livers on the backscattered statistics of ultrasound imaging.

    Science.gov (United States)

    Wan, Yung-Liang; Tai, Dar-In; Ma, Hsiang-Yang; Chiang, Bing-Hao; Chen, Chin-Kuo; Tsui, Po-Hsiang

    2015-06-01

    Ultrasound imaging has been widely applied to screen fatty liver disease. Fatty liver disease is a condition where large vacuoles of triglyceride fat accumulate in liver cells, thereby altering the arrangement of scatterers and the corresponding backscattered statistics. In this study, we used ultrasound Nakagami imaging to explore the effects of fatty infiltration in human livers on the statistical distribution of backscattered signals. A total of 107 patients volunteered to participate in the experiments. The livers were scanned using a clinical ultrasound scanner to obtain the raw backscattered signals for ultrasound B-mode and Nakagami imaging. Clinical scores of fatty liver disease for each patient were determined according to a well-accepted sonographic scoring system. The results showed that the Nakagami image can visualize the local backscattering properties of liver tissues. The Nakagami parameter increased from 0.62 ± 0.11 to 1.02 ± 0.07 as the fatty liver disease stage increased from normal to severe, indicating that the backscattered statistics vary from pre-Rayleigh to Rayleigh distributions. A significant positive correlation (correlation coefficient ρ = 0.84; probability value (p value) applications in fatty liver disease diagnosis. © IMechE 2015.

  7. 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.

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

    International Nuclear Information System (INIS)

    Wang Huaiying; Zhang Yujin; Yang Lirui; Li Dong

    2011-01-01

    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)

  9. Transmission electron imaging in the Delft multibeam scanning electron microscope 1

    NARCIS (Netherlands)

    Ren, Y.; Kruit, P.

    2016-01-01

    Our group is developing a multibeam scanning electron microscope (SEM) with 196 beams in order to increase the throughput of SEM. Three imaging systems using, respectively, transmission electron detection, secondary electron detection, and backscatter electron detection are designed in order to

  10. Microstructural evolution in adiabatic shear bands of copper at high strain rates: Electron backscatter diffraction characterization

    International Nuclear Information System (INIS)

    Tang Lin; Chen Zhiyong; Zhan Congkun; Yang Xuyue; Liu Chuming; Cai Hongnian

    2012-01-01

    The microstructural evolution of adiabatic shear bands in annealed copper with different large strains at high strain rates has been investigated by electron backscatter diffraction. The results show that mechanical twinning can occur with minimal contribution to shear localization under dynamic loading. Elongated ultrafine grains with widths of 100–300 nm are observed during the evolution of the adiabatic shear bands. A rotational dynamic recrystallization mechanism is proposed to explain the formation of the elongated ultrafine grains. - Highlights: ► The microstructural evolution of ASB is studied by electron backscatter diffraction. ► Twinning can occur in ASB while the contribution to shear localization is slight. ► Elongated ultrafine grains are observed during the evolution process of ASB. ► A possible mechanism is proposed to explain the microstructure evolution of ASB.

  11. Gas effect on the emission and detection of the backscattered electrons in a VP-SEM at low energy.

    Science.gov (United States)

    Hafsi, Z; Mansour, O; Kadoun, A; Khouchaf, L; Mathieu, C

    2018-01-01

    The effect of the electron beam skirting on the emission and detection of the backscattered electrons (BSE) in a low vacuum scanning electron microscope is investigated at low energy regime. Monte Carlo computed dependencies of the BSE distribution on the water vapor and air pressure shown a significant increase of the extent of the BSE exit zone. The pressure variation has however a little effect when helium gas is used. A new approach based on the comparison between the sizes of the skirt and the BSE exit zone on the specimen surface provides a useful tool to determine the operating pressure range that ensures minimal degradation of the lateral resolution in BSE imaging mode. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Energy analyzer for Auger electron spectroscopy and low-energy backscattering ion spectroscopy

    International Nuclear Information System (INIS)

    Volkov, S.S.; Gorelik, V.A.; Gutenko, V.T.; Protopopov, O.D.; Trubitsin, A.A.; Shuvalova, Z.A.; Yakushev, G.A.

    1988-01-01

    Energy analyzer for electron Auger spectroscopy and low-energy backscattering ion spectroscopy is described. Analyzer presents one-cascade variant of cylindrical mirror with second-order focusing. Energy relative resolution is continuously adjusted within 0.2-1.2% limits. Signal/noise relation by Cu Auger-line at 1 muA current of exciting beam changes upper limit of range 150-450

  13. Backscattered electron technique used for studying the grain boundary structure in polycrystals

    International Nuclear Information System (INIS)

    Lopes, Luiz Carlos Rolim; Thomson, Chris Boyd; Randle, Valerie

    1996-01-01

    In this work the electron backscatter diffraction technique has been used to study the grain boundary character distribution in a austenitic steel and a ordered intermetallic Fe Al. For the first material it has been found that the hot rolling and solubilization process produce grain boundary character distribution with 1/4 of Σ = 3 interface. For the intermetallic Fe Al it was found that Σ = 1 and Σ = 5 interfaces to do not show tendency to show intergranular cracking. (author)

  14. 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.

  15. Metallographic Preparation of Space Shuttle Reaction Control System Thruster Electron Beam Welds for Electron Backscatter Diffraction

    Science.gov (United States)

    Martinez, James

    2011-01-01

    A Space Shuttle Reaction Control System (RCS) thruster failed during a firing test at the NASA White Sands Test Facility (WSTF), Las Cruces, New Mexico. The firing test was being conducted to investigate a previous electrical malfunction. A number of cracks were found associated with the fuel closure plate/injector assembly (Fig 1). The firing test failure generated a flight constraint to the launch of STS-133. A team comprised of several NASA centers and other research institutes was assembled to investigate and determine the root cause of the failure. The JSC Materials Evaluation Laboratory was asked to compare and characterize the outboard circumferential electron beam (EB) weld between the fuel closure plate (Titanium 6Al-4V) and the injector (Niobium C-103 alloy) of four different RCS thrusters, including the failed RCS thruster. Several metallographic challenges in grinding/polishing, and particularly in etching were encountered because of the differences in hardness, ductility, and chemical resistance between the two alloys and the bimetallic weld. Segments from each thruster were sectioned from the outboard weld. The segments were hot-compression mounted using a conductive, carbon-filled epoxy. A grinding/polishing procedure for titanium alloys was used [1]. This procedure worked well on the titanium; but a thin, disturbed layer was visible on the niobium surface by means of polarized light. Once polished, each sample was micrographed using bright field, differential interference contrast optical microscopy, and scanning electron microscopy (SEM) using a backscatter electron (BSE) detector. No typical weld anomalies were observed in any of the cross sections. However, areas of large atomic contrast were clearly visible in the weld nugget, particularly along fusion line interfaces between the titanium and the niobium. This prompted the need to better understand the chemistry and microstructure of the weld (Fig 2). Energy Dispersive X-Ray Spectroscopy (EDS

  16. Determination of dislocation density by electron backscatter diffraction and X-ray line profile analysis in ferrous lath martensite

    International Nuclear Information System (INIS)

    Berecz, Tibor; Jenei, Péter; Csóré, András; Lábár, János; Gubicza, Jenő

    2016-01-01

    The microstructure and the dislocation density in as-quenched ferrous lath martensite were studied by different methods. The blocks, packets and variants formed due to martensitic transformation were identified and their sizes were determined by electron backscatter diffraction (EBSD). Concomitant transmission electron microscopy (TEM) investigation revealed that the laths contain subgrains with the size between 50 and 100 nm. A novel evaluation procedure of EBSD images was elaborated for the determination of the density and the space distribution of geometrically necessary dislocations from the misorientation distribution. The total dislocation density obtained by X-ray diffraction line profile analysis was in good agreement with the value determined by EBSD, indicating that the majority of dislocations formed due to martensitic transformation during quenching are geometrically necessary dislocations.

  17. Implementation of a near backscattering imaging system on the National Ignition Facility

    International Nuclear Information System (INIS)

    Mackinnon, A.J.; McCarville, T.; Piston, K.; Niemann, C.; Jones, G.; Reinbachs, I.; Costa, R.; Celeste, J.; Holtmeier, G.; Griffith, R.; Kirkwood, R.; MacGowan, B.; Glenzer, S.H.; Latta, M.R.

    2004-01-01

    A near backscattering imaging diagnostic system is being implemented on the first quad of beams on the National Ignition Facility. This diagnostic images diffusing scatter plates, placed around the final focus lenses on the National Ignition Facility target chamber, to quantitatively measure the fraction of light backscattered outside of the focusing cone angle of incident laser beam. A wide-angle imaging system relays an image of light scattered outside the lens onto a gated charge coupled device camera, providing 3 mm resolution over a 2 m field of view. To account for changes of the system throughput due to exposure to target debris the system will be routinely calibrated in situ at 532 and 355 nm using a dedicated pulsed laser source

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

    International Nuclear Information System (INIS)

    Cortes, M.L.; Merchan, E.; Blanco, W.J.; Cristancho, F.; Gerl, J.; Ameil, F.

    2010-01-01

    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)

  19. Backscattered electron emission after proton impact on carbon and gold films: Experiments and simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hespeels, F.; Heuskin, A.C. [University of Namur, PMR, 61 rue de Bruxelles, B-5000 Namur (Belgium); Scifoni, E. [TIFPA-INFN, Trento Institute for Fundamental Physics and Applications, Via Sommarive 14, I-38123 Trento (Italy); GSI-Helmholtzzentrum für Schwerionenforschung, Biophysik, Max Planck-Strasse 1, D-64291 Darmstadt (Germany); Kraemer, M. [GSI-Helmholtzzentrum für Schwerionenforschung, Biophysik, Max Planck-Strasse 1, D-64291 Darmstadt (Germany); Lucas, S., E-mail: stephane.lucas@unamur.be [University of Namur, PMR, 61 rue de Bruxelles, B-5000 Namur (Belgium)

    2017-06-15

    This work aims at measuring the proton induced secondary electron energy spectra from nanometer thin films. Backscattered electron energy spectra were measured within an energy range from 0 to 600 eV using a Retarding Field Analyser (RFA). This paper presents energy spectra obtained for proton (0.5 MeV; 1 MeV; 1.5 MeV; 2 MeV) irradiation of thin carbon films (50 and 100 nm thick) and thin gold film (200 nm). These experimental spectra were compared with Monte Carlo simulations based on TRAX code and Geant4 simulation toolkit. Good agreement between experimental, TRAX and Geant4 results were observed for the carbon target. For the gold target, we report major differences between both Monte Carlo environments. Limitation of Geant4 models for low energy electron emission was highlighted. On the contrary, TRAX simulations present encouraging results for the modeling of low-energy electron emission from gold target.

  20. Comparative study of macrotexture analysis using X-ray diffraction and electron backscattered diffraction techniques

    International Nuclear Information System (INIS)

    Serna, Marilene Morelli

    2002-01-01

    The macrotexture is one of the main characteristics in metallic materials, which the physical properties depend on the crystallographic direction. The analysis of the macrotexture to middles of the decade of 80 was just accomplished by the techniques of Xray diffraction and neutrons diffraction. The possibility of the analysis of the macrotexture using, the technique of electron backscattering diffraction in the scanning electronic microscope, that allowed to correlate the measure of the orientation with its location in the micro structure, was a very welcome tool in the area of engineering of materials. In this work it was studied the theoretical aspects of the two techniques and it was used of both techniques for the analysis of the macrotexture of aluminum sheets 1050 and 3003 with intensity, measured through the texture index 'J', from 2.00 to 5.00. The results obtained by the two techniques were shown reasonably similar, being considered that the statistics of the data obtained by the technique of electron backscatter diffraction is much inferior to the obtained by the X-ray diffraction. (author)

  1. Terahertz Imaging and Backscatter Radiography Probability of Detection Study for Space Shuttle Foam Inspections

    Science.gov (United States)

    Ussery, Warren; Johnson, Kenneth; Walker, James; Rummel, Ward

    2008-01-01

    This slide presentation reviews the use of terahertz imaging and Backscatter Radiography in a probability of detection study of the foam on the external tank (ET) shedding and damaging the shuttle orbiter. Non-destructive Examination (NDE) is performed as one method of preventing critical foam debris during the launch. Conventional NDE methods for inspection of the foam are assessed and the deficiencies are reviewed. Two methods for NDE inspection are reviewed: Backscatter Radiography (BSX) and Terahertz (THZ) Imaging. The purpose of the Probability of Detection (POD) study was to assess performance and reliability of the use of BSX and or THZ as an appropriate NDE method. The study used a test article with inserted defects, and a sample of blanks included to test for false positives. The results of the POD study are reported.

  2. First combined electron backscatter diffraction and transmission electron microscopy study of grain boundary structure of deformed quartzite.

    Science.gov (United States)

    Shigematsu, N; Prior, D J; Wheeler, J

    2006-12-01

    The structures of boundaries in a deformed and dynamically recovered and recrystallized quartz polycrystal (mylonite) were characterized by transmission electron microscopy, after the misorientation angles across the same grain boundaries had been analysed using electron backscatter diffraction in a scanning electron microscope. In this new approach, a specific sample area is mapped with electron backscatter diffraction, and the mapped area is then attached to a foil, and by the ion beam thinned for transmission electron microscopy analysis. Dislocations in grain boundaries were recognized as periodic and parallel fringes. The fringes associated with dislocations are observed in boundaries with misorientations less than 9 degrees , whereas such fringes cannot be seen in the boundaries with misorientations larger than 17 degrees . Some boundaries with misorientations between 9 degrees and 17 degrees generally have no structures associated with dislocation. One segment of a boundary with a misorientation of 13.5 degrees has structures associated with dislocations. It is likely that the transition from low-angle to high-angle boundaries occurs at misorientations ranging from approximately 9 degrees to 14 degrees . Change in the grain boundary structure presumably influences the mobility of the boundaries. In the studied deformed quartz vein, a relative dearth of boundaries between misorientation angles of theta = 2 degrees and theta = 15 degrees has previously been reported, and high-angle boundaries form cusps where they intersect low-angle boundaries, suggesting substantial mobility of high-angle boundaries.

  3. A Monte Carlo investigation of saturation thickness and attenuation coefficient for backscattered and transmitted electrons of continuum spectrum

    International Nuclear Information System (INIS)

    Abrahantes, Arian; Diaz, Rafael

    2003-01-01

    Reliable data on electron backscattering in different media are not available in literature, even more for electrons of continuum spectrum. Material's parameters which depend or could be inferred from those data might have some uncertainties. Back in 1978, K. K. Sharma and M. Singh determined the value of saturation thickness for backscattered electrons and attenuation coefficient in some metals for radioisotopical sources of 90 Sr/ 90 Y and 204 Ti in a particular experimental set up. In this work, new values of those parameters were calculated by Monte Carlo transport of electrons in different materials. The saturation thickness was found to be dependent of the material atomic number and an explanation was proposed to interpret the obtained behavior. Furthermore, results of attenuation coefficient and the saturation thickness differed from those reported by Sharma. It is also mentioned a consideration to Sharma's empirical relation for backscattered intensity of beta particles

  4. 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...

  5. 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.

    to compensate outer-beam backscatter strength data in such a way that the effect of angular backscatter strength is removed. In this work we have developed backscatter data processing techniques for EM1002 multi-beam system...

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

    Energy Technology Data Exchange (ETDEWEB)

    Friedman, Lawrence H.; Vaudin, Mark D.; Stranick, Stephan J.; Stan, Gheorghe; Gerbig, Yvonne B.; Osborn, William; Cook, Robert F., E-mail: robert.cook@nist.gov

    2016-04-15

    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{sup −4} in strain. CRM was similarly precise, but was limited in accuracy to several times this value. - Highlights: • We map strain by electron backscatter diffraction and confocal Raman microscopy. • The test vehicle is the multi-axial strain field of wedge-indented silicon. • Strain accuracy is assessed by direct experimental intercomparison. • Accuracy is also assessed by atomic force microscopy and finite element analyses. • Electron diffraction measurements are accurate; Raman measurements need refinement.

  7. A flying spot x-ray system for Compton backscatter imaging

    International Nuclear Information System (INIS)

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

    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 3-D 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 delivered by this imaging device. Validation experiments with mechanical models show that surface displacement of typical heart beam frequencies can be measured to the nearest 0.1 mm (SD)

  8. Total electron count variability and stratospheric ozone effects on solar backscatter and LWIR emissions

    Science.gov (United States)

    Ross, John S.; Fiorino, Steven T.

    2017-05-01

    The development of an accurate ionospheric Total Electron Count (TEC) model is of critical importance to high frequency (HF) radio propagation and satellite communications. However, the TEC is highly variable and is continually influenced by geomagnetic storms, extreme UV radiation, and planetary waves. Being able to capture this variability is essential to improve current TEC models. The growing body of data involving ionospheric fluctuations and stratospheric variations has revealed a correlation. In particular, there is a marked and persistent association between increases in stratospheric ozone and variability of the TEC. The spectral properties of ozone show that it is a greenhouse gas that alters long wave emissions from Earth and interacts with the UV spectrum coming from the sun. This study uses the Laser Environment Effects Definition and Reference (LEEDR) radiative transfer and atmospheric characterization code to model the effects of changes in stratospheric ozone on solar backscatter and longwave (LWIR) terrestrial emissions and infer TEC and TEC variability.

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

    DEFF Research Database (Denmark)

    Saowadee, Nath

    structure. In this case, lattice parameters analysis aid to differential the secondary phases. However lattice constant of secondary phase cannot measure by general tools such as x-ray diffraction due to its insufficiency. Point analysis in electron backscattered diffraction (EBSDX allows measuring......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...... 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...

  10. 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. © 2013 The Authors Journal of Microscopy © 2013 Royal Microscopical Society.

  11. High resolution electron backscatter diffraction (EBSD) data from calcite biominerals in recent gastropod shells.

    Science.gov (United States)

    Pérez-Huerta, Alberto; Dauphin, Yannicke; Cuif, Jean Pierre; Cusack, Maggie

    2011-04-01

    Electron backscatter diffraction (EBSD) is a microscopy technique that reveals in situ crystallographic information. Currently, it is widely used for the characterization of geological materials and in studies of biomineralization. Here, we analyze high resolution EBSD data from biogenic calcite in two mollusk taxa, Concholepas and Haliotis, previously used in the understanding of complex biomineralization and paleoenvironmental studies. Results indicate that Concholepas has less ordered prisms than in Haliotis, and that in Concholepas the level of order is not homogenous in different areas of the shell. Overall, the usefulness of data integration obtained from diffraction intensity and crystallographic orientation maps, and corresponding pole figures, is discussed as well as its application to similar studies. © 2010 Elsevier Ltd. All rights reserved.

  12. Practical considerations in the calculation of orientation distribution functions from electron back-scattered diffraction patterns

    International Nuclear Information System (INIS)

    Bowen, A.W.

    1994-01-01

    Using model data sets for the Brass orientation, the importance of scatter width, angular accuracy and grain size and volume fraction on the sensitivity of the calculated Orientation Distribution Functions have been determined in order to highlight some of the practical considerations needed in the processing of experimental data from individual grain orientation measurements determined by the Electron Back-Scattered Diffraction technique. It is suggested that the most appropriate scatter width can be calculated from the maximum function height versus scatter width curve in order to accommodate variations in texture sharpness. The sensitivity of the ODF to careful sample preparation, mounting and pattern analysis, in order to keep errors in angular accuracy to 1 or less is demonstrated, as is the imperative need to correct for the size of grains, and their volume fractions. (orig.)

  13. Optical transmission of glass for the National Ignition Facility near backscatter imagers under x-ray exposurea)

    Science.gov (United States)

    London, R. A.; Froula, D. H.; Sorce, C. M.; Moody, J. D.; Suter, L. J.; Glenzer, S. H.; Jones, O. S.; Meezan, N. B.; Rosen, M. D.

    2008-10-01

    In experiments at the National Ignition Facility (NIF), the near backscatter imager materials need to maintain high optical transmission while exposed to hohlraum generated x rays. Glass plates are incorporated in the design to protect the optical scattering plates from x-ray damage. Radiation environments spanning those expected on NIF have been produced at the Omega Laser Facility by symmetric laser illumination of 1mm sized gold spheres. The time-dependent ultraviolet transmission of sample glass plates was measured. The data are interpreted with a free electron absorption model. Combined with the simulations of the hohlraum x-ray emission, this model is used to predict the transmission of the glass plates on the NIF. We predict that the plates should perform adequately up to the peak of the laser pulse.

  14. Mechanical assessment of bovine pericardium using Müeller matrix imaging, enhanced backscattering and digital image correlation analysis.

    Science.gov (United States)

    Cuando-Espitia, Natanael; Sánchez-Arévalo, Francisco; Hernández-Cordero, Juan

    2015-08-01

    Mechanical characterization of tissue is an important but complex task. We demonstrate the simultaneous use of Mueller matrix imaging (MMI), enhanced backscattering (EBS) and digital image correlation (DIC) in a bovine pericardium (BP) tensile test. The interest in BP relies on its wide use as valve replacement and biological patch. We show that the mean free path (MFP), obtained through EBS measurements, can be used as an indicator of the anisotropy of the fiber ensemble. Our results further show a good correlation between retardance images and displacement vector fields, which are intrinsically related with the fiber interaction within the tissue.

  15. 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...

  16. Response function and optimum configuration of semiconductor backscattered-electron detectors for scanning electron microscopes

    International Nuclear Information System (INIS)

    Rau, E. I.; Orlikovskiy, N. A.; Ivanova, E. S.

    2012-01-01

    A new highly efficient design for semiconductor detectors of intermediate-energy electrons (1–50 keV) for application in scanning electron microscopes is proposed. Calculations of the response function of advanced detectors and control experiments show that the efficiency of the developed devices increases on average twofold, which is a significant positive factor in the operation of modern electron microscopes in the mode of low currents and at low primary electron energies.

  17. 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.

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

    International Nuclear Information System (INIS)

    Wang Huaiying; Yang Lirui; Zhang Yujin

    2010-01-01

    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)

  19. Imaging near-surface heterogeneities by natural migration of backscattered surface waves: Field data test

    KAUST Repository

    Liu, Zhaolun

    2017-03-06

    We have developed a methodology for detecting the presence of near-surface heterogeneities by naturally migrating backscattered surface waves in controlled-source data. The near-surface heterogeneities must be located within a depth of approximately one-third the dominant wavelength λ of the strong surface-wave arrivals. This natural migration method does not require knowledge of the near-surface phase-velocity distribution because it uses the recorded data to approximate the Green’s functions for migration. Prior to migration, the backscattered data are separated from the original records, and the band-passed filtered data are migrated to give an estimate of the migration image at a depth of approximately one-third λ. Each band-passed data set gives a migration image at a different depth. Results with synthetic data and field data recorded over known faults validate the effectiveness of this method. Migrating the surface waves in recorded 2D and 3D data sets accurately reveals the locations of known faults. The limitation of this method is that it requires a dense array of receivers with a geophone interval less than approximately one-half λ.

  20. 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.

  1. 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.

  2. The effect of pattern overlap on the accuracy of high resolution electron backscatter diffraction measurements

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Vivian, E-mail: v.tong13@imperial.ac.uk [Department of Materials, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom); Jiang, Jun [Department of Materials, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom); Wilkinson, Angus J. [Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH (United Kingdom); Britton, T. Ben [Department of Materials, Imperial College London, Prince Consort Road, London SW7 2AZ (United Kingdom)

    2015-08-15

    High resolution, cross-correlation-based, electron backscatter diffraction (EBSD) measures the variation of elastic strains and lattice rotations from a reference state. Regions near grain boundaries are often of interest but overlap of patterns from the two grains could reduce accuracy of the cross-correlation analysis. To explore this concern, patterns from the interior of two grains have been mixed to simulate the interaction volume crossing a grain boundary so that the effect on the accuracy of the cross correlation results can be tested. It was found that the accuracy of HR-EBSD strain measurements performed in a FEG-SEM on zirconium remains good until the incident beam is less than 18 nm from a grain boundary. A simulated microstructure was used to measure how often pattern overlap occurs at any given EBSD step size, and a simple relation was found linking the probability of overlap with step size. - Highlights: • Pattern overlap occurs at grain boundaries and reduces HR-EBSD accuracy. • A test is devised to measure the accuracy of HR-EBSD in the presence of overlap. • High pass filters can sometimes, but not generally, improve HR-EBSD measurements. • Accuracy of HR-EBSD remains high until the reference pattern intensity is <72%. • 9% of points near a grain boundary will have significant error for 200nm step size in Zircaloy-4.

  3. Analysis of soft magnetic materials by electron backscatter diffraction as a powerful tool

    Science.gov (United States)

    Schuller, David; Hohs, Dominic; Loeffler, Ralf; Bernthaler, Timo; Goll, Dagmar; Schneider, Gerhard

    2018-04-01

    The current work demonstrates that electron backscatter diffraction (EBSD) is a powerful and versatile characterization technique for investigating soft magnetic materials. The properties of soft magnets, e.g., magnetic losses strongly depend on the materials chemical composition and microstructure, including grain size and shape, texture, degree of plastic deformation and elastic strain. In electrical sheet stacks for e-motor applications, the quality of the machined edges/surfaces of each individual sheet is of special interest. Using EBSD, the influence of the punching process on the microstructure at the cutting edge is quantitatively assessed by evaluating the crystallographic misorientation distribution of the deformed grains. Using an industrial punching process, the maximum affected deformation depth is determined to be 200 - 300 μm. In the case of laser cutting, the affected deformation depth is determined to be approximately zero. Reliability and detection limits of the developed EBSD approach are evaluated on non-affected sample regions and model samples containing different indentation test bodies. A second application case is the investigation of the recrystallization process during the annealing step of soft magnetic composites (SMC) toroids produced by powder metallurgy as a function of compaction pressure, annealing parameters and powder particle size. With increasing pressure and temperature, the recrystallized area fraction (e.g., grains with crystallographic misorientations size distributions. Here, large particles with coarse internal grain structures show a favorable recrystallization behavior which results in large bulk permeability of up to 600 - 700 and lower amount of residual misorientations (>3°).

  4. Reconstruction of Laser-Induced Surface Topography from Electron Backscatter Diffraction Patterns.

    Science.gov (United States)

    Callahan, Patrick G; Echlin, McLean P; Pollock, Tresa M; De Graef, Marc

    2017-08-01

    We demonstrate that the surface topography of a sample can be reconstructed from electron backscatter diffraction (EBSD) patterns collected with a commercial EBSD system. This technique combines the location of the maximum background intensity with a correction from Monte Carlo simulations to determine the local surface normals at each point in an EBSD scan. A surface height map is then reconstructed from the local surface normals. In this study, a Ni sample was machined with a femtosecond laser, which causes the formation of a laser-induced periodic surface structure (LIPSS). The topography of the LIPSS was analyzed using atomic force microscopy (AFM) and reconstructions from EBSD patterns collected at 5 and 20 kV. The LIPSS consisted of a combination of low frequency waviness due to curtaining and high frequency ridges. The morphology of the reconstructed low frequency waviness and high frequency ridges matched the AFM data. The reconstruction technique does not require any modification to existing EBSD systems and so can be particularly useful for measuring topography and its evolution during in situ experiments.

  5. Application of electron backscatter diffraction (EBSD) to fracture studies of ferritic steels.

    Science.gov (United States)

    Davies, P A; Novovic, M; Randle, V; Bowen, P

    2002-03-01

    The application of electron backscatter diffraction (EBSD) to fracture studies has provided a new method for investigating the crystallography of fracture surfaces. The crystallographic indices of cleavage planes can be measured both directly from the fracture surface and indirectly from metallographic sections perpendicular to the plane of the adjoining fracture surfaces. The results of direct individual cleavage facet plane orientation measurements are presented for carbon-manganese (C-Mn) and low-alloy Mn-Mo-Ni (similar to ASTM A553 type-B). Pressure vessel steel weld metals, obtained from fracture surfaces of Charpy impact test specimens fractured at various test temperatures and for an ultra-low carbon steel (Fe-0.002C- 0.058P) fractured at -196 degrees C by impact. In addition to the direct measurement from the fracture surface, cleavage facet orientation measurements for the ultra-low carbon steel were complemented by the results obtained from the metallographic sections. Fractographic observations revealed that cleavage fracture is accommodated by a microvoid coalescence fracture micromechanism, which was induced by decohesion of second phase particles (inclusions). The correlation between the direct and indirect methodologies shows that the cleavage facet planes are dominated by the [001] plane orientations, and indicated that even when information concerning the full five degrees of freedom is inaccessible, the cleavage facet plane could still be determined. Finally, the advantages and disadvantages of direct orientation measurements from the fracture surface and indirectly by a destructive sectioning technique are discussed.

  6. In situ electron backscatter diffraction (EBSD) during the compression of micropillars

    International Nuclear Information System (INIS)

    Niederberger, C.; Mook, W.M.; Maeder, X.; Michler, J.

    2010-01-01

    For the first time, in situ electron backscatter diffraction (EBSD) measurements during compression experiments by a modified nanoindenter on micron-sized single crystal pillars are demonstrated here. The experimental setup and the requirements concerning the compression sample are described in detail. EBSD mappings have been acquired before loading, under load and after unloading for consecutive compression cycles on a focused ion beam (FIB) milled GaAs micropillar. In situ EBSD allows for the determination of crystallographic orientation with sub-100 nm spatial resolution. Thereby, it provides highly localized information pertaining to the deformation phenomena such as elastic bending of the micropillar or the formation of deformation twins and plastic orientation gradients due to geometrically necessary dislocations. The most striking features revealed by in situ EBSD are the non-negligible amount of reversible (elastic) bending of the micropillar and the fact that deformation twinning and dislocation glide initiate where the bending is strongest. Due to this high spatial and orientation resolution, in situ EBSD measurements during micromechanical testing are demonstrated to be a promising technique for the investigation of deformation phenomena at the nano- to micro-scale.

  7. Electron Backscatter Diffraction Studies on the Formation of Superlattice Metal Hydride Alloys

    Directory of Open Access Journals (Sweden)

    Shuli Yan

    2017-12-01

    Full Text Available Microstructures of a series of La-Mg-Ni-based superlattice metal hydride alloys produced by a novel method of interaction of a LaNi5 alloy and Mg vapor were studied using a combination of X-ray energy dispersive spectroscopy and electron backscatter diffraction. The conversion rate of LaNi5 increased from 86.8% into 98.2%, and the A2B7 phase abundance increased from 42.5 to 45.8 wt % and reduced to 39.2 wt % with the increase in process time from four to 32 h. During the first stage of reaction, Mg formed discrete grains with the same orientation, which was closely related to the orientation of the host LaNi5 alloy. Mg then diffused through the ab-phase of LaNi5 and formed the AB2, AB3, and A2B7 phases. Diffusion of Mg stalled at the grain boundary of the host LaNi5 alloy. Good alignments in the c-axis between the newly formed superlattice phases and LaNi5 were observed. The density of high-angle grain boundary decreased with the increase in process time and was an indication of lattice cracking.

  8. Experimental evidence concerning the significant information depth of electron backscatter diffraction (EBSD)

    Energy Technology Data Exchange (ETDEWEB)

    Wisniewski, Wolfgang, E-mail: wolfgang.w@uni-jena.de [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany); Saager, Stefan [Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, Winterbergstraße 28, 01277 Dresden (Germany); Böbenroth, Andrea [Fraunhofer Institute for the Microstructure of Materials and Systems IMWS, Walter-Huelse-Straße 1, 06120 Halle (Saale) (Germany); Rüssel, Christian [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany)

    2017-02-15

    Experiments concerning the information depth of electron backscatter diffraction (EBSD) are performed on samples featuring an amorphous wedge on a crystalline substrate and a crystalline wedge on an amorphous substrate. The effects of the acceleration voltage and exemplary software settings on the ability to measure through an amorphous layer are presented. Changes in the EBSD-signal could be detected through a ≈142 nm thick layer of amorphous Si while orientation measurements could be performed through a ≈116 nm thick layer when using a voltage of 30 kV. The complexity of the information depth significant to a given EBSD-pattern and the multiple parameters influencing it are discussed. It is suggested that a “core information depth” is significant to high quality patterns while a larger “maximum information depth” becomes relevant when the pattern quality decreases or the sample is inhomogeneous within the information volume, i.e. in the form of partially crystalline materials or crystal layers in the nm scale. - Highlights: • Experimental evidence of the significant information depth of EBSD is presented. • Effects of the voltage and exemplary software settings are discussed. • Dependence of the significant information depth on the pattern quality is proposed. • The information depth may reach up to 142 nm in Si when using a voltage of 30 kV. • The information depth depends on the available technology.

  9. Microstructural analysis of quartz crystals in an andalusite-cordierite schist using electron backscatter diffraction

    International Nuclear Information System (INIS)

    Rahimi-Chakdel, A.; Boyle, A. P.

    2012-01-01

    The present study investigates the shape preferred orientation and crystal preferred orientation of quartz crystals using electron backscatter diffraction in andalusite-cordierite schist from the Ythan Valley, Aberdeenshire, in the Scottish Dalradian block. Quartz crystals in the matrix and andalusite pophyroblasts have inequant to slightly equant shapes. Quartz crystals show weak shape preferred orientation in the matrix and andalusite pophyroblasts, which are sub-parallel to each other. The weak shape preferred orientation in quartz crystals of the studied sample can be related to (1) Grain boundary migration of quartz crystals and (2) non-quartz crystals (e.g. mica) at junction of quartz crystals. Also, quartz crystals show random crystal preferred orientation in the matrix and inclusion. The lack of crystal preferred orientation of quartz crystals in the matrix can be explained by (i) absence, or low amounts of strain in the rock that is experienced only low temperature and pressure and (ii) diffusion creep. The random crystallographic orientation of quartz inclusions may confirm non-selective orientations of the matrix quartz crystals by andalusite pophyroblast during growth.

  10. Initial microstructural study of a Ce-La alloy using electron backscattered diffraction

    International Nuclear Information System (INIS)

    Scott, Thomas B.; Younes, Charles M.; Ling, Michael; Jones, Christopher P.; Nicholson, John A.; Heard, Peter J.; Jenkins, Roderick

    2011-01-01

    Research highlights: → First ever successful EBSD microstructural analysis of Ce-La alloy. → Successful preparation using electro-polishing in the open laboratory. → Equiaxed grains 20-40 μm in size dominate the microstructure, with random orientations, relatively straight grain boundary contacts and no evidence for crystal twinning. → All grains matched to a fcc γ-phase. → Problematic presence of entrapped oxide particles. - Abstract: To better understand and exploit the unique electronic and structural properties of f-block metals and their alloys it is perceived that an improved knowledge of the microstructural characteristics and phase changes as a function of temperature and pressure, is necessary. For other different types of metallic systems, the use of electron back-scattered diffraction (EBSD) is becoming a common practice in order to obtain detailed microstructural information, but this has, as yet, been very limited in case of f-block metals. Because of their extreme affinity to oxygen and rapid surface reaction, EBSD studies of this metal-category are very sparse with only one work published on cerium metal providing an example of technical hurdles for a prerequisite oxide-free metal surface. Specifically the need to remove the oxide by ion etching was considered essential to enable a successful EBSD analysis. The current work presents the results of a first attempt to characterise the microstructure of a Ce-La alloy using EBSD. It demonstrates that high quality diffraction patterns and crystal orientation maps can be successfully obtained following a carefully controlled preparation of the alloy surface in the open laboratory by applying a simple and reproducible electro-polishing procedure without a further need for ion etching in vaccuo.

  11. Electron Paramagnetic Resonance Imaging

    Indian Academy of Sciences (India)

    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 ...

  12. A flying spot x-ray system for Compton backscatter imaging

    Energy Technology Data Exchange (ETDEWEB)

    Herr, M.D.; McInerney, J.J.; Copenhaver, G.L. (Pennsylvania State Univ., Hershey, PA (United States)); Lamser, D.G. (Hologic, Waltham, MA (United States))

    1994-09-01

    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 3-D 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 delivered by this imaging device. Validation experiments with mechanical models show that surface displacement of typical heart beam frequencies can be measured to the nearest 0.1 mm (SD).

  13. THE LOW BACKSCATTERING OBJECTS CLASSIFICATION IN POLSAR IMAGE BASED ON BAG OF WORDS MODEL USING SUPPORT VECTOR MACHINE

    Directory of Open Access Journals (Sweden)

    L. Yang

    2018-04-01

    Full Text Available Due to the forward scattering and block of radar signal, the water, bare soil, shadow, named low backscattering objects (LBOs, often present low backscattering intensity in polarimetric synthetic aperture radar (PolSAR image. Because the LBOs rise similar backscattering intensity and polarimetric responses, the spectral-based classifiers are inefficient to deal with LBO classification, such as Wishart method. Although some polarimetric features had been exploited to relieve the confusion phenomenon, the backscattering features are still found unstable when the system noise floor varies in the range direction. This paper will introduce a simple but effective scene classification method based on Bag of Words (BoW model using Support Vector Machine (SVM to discriminate the LBOs, without relying on any polarimetric features. In the proposed approach, square windows are firstly opened around the LBOs adaptively to determine the scene images, and then the Scale-Invariant Feature Transform (SIFT points are detected in training and test scenes. The several SIFT features detected are clustered using K-means to obtain certain cluster centers as the visual word lists and scene images are represented using word frequency. At last, the SVM is selected for training and predicting new scenes as some kind of LBOs. The proposed method is executed over two AIRSAR data sets at C band and L band, including water, bare soil and shadow scenes. The experimental results illustrate the effectiveness of the scene method in distinguishing LBOs.

  14. Effect of different electron elastic-scattering cross sections on inelastic mean free paths obtained from elastic-backscattering experiments

    International Nuclear Information System (INIS)

    Jablonskiz, A.; Salvatz, F.; Powellz, C.J.

    2004-01-01

    Inelastic mean free paths (IMFPs) of electrons with energies between 100 eV and 5,000 eV have been frequently obtained from measurements of elastic-backscattering probabilities for different specimen materials. A calculation of these probabilities is also required to determine IMFPs. We report calculations of elastic-backscattering probabilities for gold at energies of 100 eV and 500 eV with differential elastic-scattering cross sections obtained from the Thomas-Fermi-Dirac potential and the more reliable Dirac-Hartree-Fock potential. For two representative experimental configurations, the average deviation between IMFPs obtained with cross sections from the two potentials was 11.4 %. (author)

  15. Distinguishing Biologically Controlled Calcareous Biomineralization in Fossil Organisms Using Electron Backscatter Diffraction (EBSD)

    Science.gov (United States)

    Päßler, Jan-Filip; Jarochowska, Emilia; Bestmann, Michel; Munnecke, Axel

    2018-02-01

    Although carbonate-precipitating cyanobacteria are ubiquitous in aquatic ecosystems today, the criteria used to identify them in the geological record are subjective and rarely testable. Differences in the mode of biomineralization between cyanobacteria and eukaryotes, i.e. biologically induced calcification (BIM) vs. biologically controlled calcification (BCM), result in different crystallographic structures which might be used as a criterion to test cyanobacterial affinities. Cyanobacteria are often used as a ‘wastebasket taxon’, to which various microfossils are assigned. The lack of a testable criterion for the identification of cyanobacteria may bias their fossil record severely. We employed electron backscatter diffraction (EBSD) to investigate the structure of calcareous skeletons in two microproblematica widespread in Palaeozoic marine ecosystems: Rothpletzella, hypothesized to be a cyanobacterium, and an incertae sedis microorganism Allonema. We used a calcareous trilobite shell as a BCM reference. The mineralized structure of Allonema has a simple single-layered structure of acicular crystals perpendicular to the surface of the organism. The c-axes of these crystals are parallel to the elongation and thereby normal to the surface of the organism. EBSD pole figures and misorientation axes distribution reveal a fibre texture around the c-axis with a small degree of variation (up to 30°), indicating a highly ordered structure. A comparable pattern was found in the trilobite shell. This structure allows excluding biologically induced mineralization as the mechanism of shell formation in Allonema. In Rothpletzella, the c-axes of the microcrystalline sheath show a broader clustering compared to Allonema, but still reveal crystals tending to be perpendicular to the surface of the organism. The misorientation axes of adjacent crystals show an approximately random distribution. Rothpletzella also shares morphological similarities with extant cyanobacteria. We

  16. Distinguishing Biologically Controlled Calcareous Biomineralization in Fossil Organisms Using Electron Backscatter Diffraction (EBSD

    Directory of Open Access Journals (Sweden)

    Jan-Filip Päßler

    2018-02-01

    Full Text Available Although carbonate-precipitating cyanobacteria are ubiquitous in aquatic ecosystems today, the criteria used to identify them in the geological record are subjective and rarely testable. Differences in the mode of biomineralization between cyanobacteria and eukaryotes, i.e., biologically induced calcification (BIM vs. biologically controlled calcification (BCM, result in different crystallographic structures which might be used as a criterion to test cyanobacterial affinities. Cyanobacteria are often used as a “wastebasket taxon,” to which various microfossils are assigned. The lack of a testable criterion for the identification of cyanobacteria may bias their fossil record severely. We employed electron backscatter diffraction (EBSD to investigate the structure of calcareous skeletons in two microproblematica widespread in Palaeozoic marine ecosystems: Rothpletzella, hypothesized to be a cyanobacterium, and an incertae sedis microorganism Allonema. We used a calcareous trilobite shell as a BCM reference. The mineralized structure of Allonema has a simple single-layered structure of acicular crystals perpendicular to the surface of the organism. The c-axes of these crystals are parallel to the elongation and thereby normal to the surface of the organism. EBSD pole figures and misorientation axes distribution reveal a fiber texture around the c-axis with a small degree of variation (up to 30°, indicating a highly ordered structure. A comparable pattern was found in the trilobite shell. This structure allows excluding biologically induced mineralization as the mechanism of shell formation in Allonema. In Rothpletzella, the c-axes of the microcrystalline sheath show a broader clustering compared to Allonema, but still reveal crystals tending to be perpendicular to the surface of the organism. The misorientation axes of adjacent crystals show an approximately random distribution. Rothpletzella also shares morphological similarities with extant

  17. Mapping local anisotropy axis for scattering media using backscattering Mueller matrix imaging

    Science.gov (United States)

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

    2014-03-01

    Mueller matrix imaging techniques can be used to detect the micro-structure variations of superficial biological tissues, including the sizes and shapes of cells, the structures in cells, and the densities of the organelles. Many tissues contain anisotropic fibrous micro-structures, such as collagen fibers, elastin fibers, and muscle fibers. Changes of these fibrous structures are potentially good indicators for some pathological variations. In this paper, we propose a quantitative analysis technique based on Mueller matrix for mapping local anisotropy axis of scattering media. By conducting both experiments on silk sample and Monte Carlo simulation based on the sphere-cylinder scattering model (SCSM), we extract anisotropy axis parameters from different backscattering Mueller matrix elements. Moreover, we testify the possible applications of these parameters for biological tissues. The preliminary experimental results of human cancerous samples show that, these parameters are capable to map the local axis of fibers. Since many pathological changes including early stage cancers affect the well aligned structures for tissues, the experimental results indicate that these parameters can be used as potential tools in clinical applications for biomedical diagnosis purposes.

  18. Giant Andreev Backscattering through a Quantum Point Contact Coupled via a Disordered Two-Dimensional Electron Gas to Superconductors

    International Nuclear Information System (INIS)

    den Hartog, S.G.; van Wees, B.J.; Klapwijk, T.M.; Nazarov, Y.V.; Borghs, G.

    1997-01-01

    We have investigated the superconducting-phase-modulated reduction in the resistance of a ballistic quantum point contact (QPC) connected via a disordered two-dimensional electron gas (2DEG) to superconductors. We show that this reduction is caused by coherent Andreev backscattering of holes through the QPC, which increases monotonically by reducing the bias voltage to zero. In contrast, the magnitude of the phase-dependent resistance of the disordered 2DEG displays a nonmonotonic reentrant behavior versus bias voltage. copyright 1997 The American Physical Society

  19. 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)

    Ojima, M.; Adachi, Y.; Tomota, Y.; Ikeda, K.; Kamiyama, T.; Katada, Y.

    2009-01-01

    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.

  20. Electronic portal imaging devices

    International Nuclear Information System (INIS)

    Lief, Eugene

    2008-01-01

    The topics discussed include, among others, the following: Role of portal imaging; Port films vs. EPID; Image guidance: Elekta volume view; Delivery verification; Automation tasks of portal imaging; Types of portal imaging (Fluorescent screen, mirror, and CCD camera-based imaging; Liquid ion chamber imaging; Amorpho-silicon portal imagers; Fluoroscopic portal imaging; Kodak CR reader; and Other types of portal imaging devices); QA of EPID; and Portal dosimetry (P.A.)

  1. Monitoring imaging of lesions induced by high intensity focused ultrasound based on differential ultrasonic attenuation and integrated backscatter estimation.

    Science.gov (United States)

    Zhong, Hui; Wan, Ming-Xi; Jiang, Yi-Feng; Wang, Su-Pin

    2007-01-01

    We investigated the feasibility of two monitoring imaging methods to visualize and evaluate the high intensity focused ultrasound (HIFU) induced lesions in vitro during and after their formation, which were based on differential ultrasonic parameter estimation. Firstly, ultrasonic attenuation slope of tissue sample was estimated based on the spectral analysis of ultrasound RF backscattered signals. The differential attenuation slope maps were acquired, which were interpreted as the differences between the pretreatment image and those obtained in different stages during HIFU therapy. Secondly, ultrasonic integrated backscatter (IBS), defined as the frequency average of the backscatter transfer function over the useful bandwidth, was proposed quantitatively to evaluate the extent of lesions with the same RF signals as the first method. Differential IBS maps were also acquired to visualize temporal evolution of lesion formation. It was found in pig liver in vitro that more precise definition of the treated area was obtained from the differential IBS images than from differential attenuation slope images. Dramatic increase in both attenuation and IBS value was observed during the therapy, which may be related to dramatic enhancement of cavitation due to boiling and accompanying tissue damage. Two methods to obtain one differential image were compared and the cumulative differential image was found to be able to eliminate noises and artifacts to some extent, which was the cumulation of a series of differential images acquired from the differences between the temporally adjacent RF data frames. Moreover, we presented a bidirectional color code for identification of the artifacts due to tissue movements caused by HIFU radiation force. We conclude that cumulative differential IBS images have the potential to monitor the formation of HIFU-induced lesions.

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

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jie; Wang, Xin, E-mail: wangx@tongji.edu.cn, E-mail: mubz@tongji.edu.cn; Zhan, Qi; Huang, Shengling; Chen, Yifan; Mu, Baozhong, E-mail: wangx@tongji.edu.cn, E-mail: mubz@tongji.edu.cn [MOE Key Laboratory of Advanced Micro-Structured Materials, No. 1239 Siping Road, Shanghai 200092 (China); School of Physics Science and Engineering, Tongji University, No. 1239 Siping Road, Shanghai 200092 (China)

    2016-07-15

    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.

  3. Backscattering and absorption coefficients for electrons: Solutions of invariant embedding transport equations using a method of convergence

    International Nuclear Information System (INIS)

    Figueroa, C.; Brizuela, H.; Heluani, S. P.

    2014-01-01

    The backscattering coefficient is a magnitude whose measurement is fundamental for the characterization of materials with techniques that make use of particle beams and particularly when performing microanalysis. In this work, we report the results of an analytic method to calculate the backscattering and absorption coefficients of electrons in similar conditions to those of electron probe microanalysis. Starting on a five level states ladder model in 3D, we deduced a set of integro-differential coupled equations of the coefficients with a method know as invariant embedding. By means of a procedure proposed by authors, called method of convergence, two types of approximate solutions for the set of equations, namely complete and simple solutions, can be obtained. Although the simple solutions were initially proposed as auxiliary forms to solve higher rank equations, they turned out to be also useful for the estimation of the aforementioned coefficients. In previous reports, we have presented results obtained with the complete solutions. In this paper, we present results obtained with the simple solutions of the coefficients, which exhibit a good degree of fit with the experimental data. Both the model and the calculation method presented here can be generalized to other techniques that make use of different sorts of particle beams

  4. NOAA TIFF Image - 1 m Backscatter Mosaic of 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 St. John Shelf, US Virgin Islands. NOAA's NOS/NCCOS/CCMA Biogeography Team, in collaboration...

  5. NOAA TIFF Image - 3 m Backscatter Mosaic of the south west shore (La Parguera) of Puerto Rico, Project NF-06-03, 2006, UTM 19 WGS84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 3 meter resolution backscatter mosaic of the south west shore (La Parguera) of Puerto Rico. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  6. 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)...

  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, in...

  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 - 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...

  10. NOS TIFF Image, 3M Backscatter Mosaic La Parguera, Puerto Rico, 2006 : Project NF-06-03, UTM 19 NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 3 meter resolution backscatter mosaic of the south west shore (La Parguera) of Puerto Rico. NOAA's NOS/NCCOS/CCMA Biogeography Team, in...

  11. 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...

  12. Electron backscatter diffraction analysis of gold nanoparticles on Y1Ba2Cu3O7−δ

    International Nuclear Information System (INIS)

    Bochmann, A.; Teichert, S.; Katzer, C.; Schmidl, F.

    2015-01-01

    It has been shown recently that the incorporation of gold nanoparticles into Y 1 Ba 2 Cu 3 O 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 1 Ba 2 Cu 3 O 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

  13. Analysis of recrystallization behavior of hot-deformed austenite reconstructed from electron backscattering diffraction orientation maps of lath martensite

    International Nuclear Information System (INIS)

    Kubota, Manabu; Ushioda, Kohsaku; Miyamoto, Goro; Furuhara, Tadashi

    2016-01-01

    The recrystallization behavior of hot-deformed austenite of a 0.55% C steel at 800 °C was investigated by a method of reconstructing the parent austenite orientation map from an electron backscattering diffraction orientation map of lath martensite. Recrystallized austenite grains were clearly distinguished from un-recrystallized austenite grains. Very good correlation was confirmed between the static recrystallization behavior investigated mechanically by double-hit compression tests and the change in austenite microstructure evaluated by the reconstruction method. The recrystallization behavior of hot-deformed 0.55% C steel at 800 °C is directly revealed and it was observed that by addition of 0.1% V the recrystallization was significantly retarded.

  14. 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

  15. Use of simulation to optimize the pinhole diameter and mask thickness for an x-ray backscatter imaging system

    Science.gov (United States)

    Vella, A.; Munoz, Andre; Healy, Matthew J. F.; Lane, David; Lockley, D.

    2017-08-01

    The PENELOPE Monte Carlo simulation code was used to determine the optimum thickness and aperture diameter of a pinhole mask for X-ray backscatter imaging in a security application. The mask material needs to be thick enough to absorb most X-rays, and the pinhole must be wide enough for sufficient field of view whilst narrow enough for sufficient image spatial resolution. The model consisted of a fixed geometry test object, various masks with and without pinholes, and a 1040 x 1340 pixels' area detector inside a lead lined camera housing. The photon energy distribution incident upon masks was flat up to selected energy limits. This artificial source was used to avoid the optimisation being specific to any particular X-ray source technology. The pixelated detector was modelled by digitising the surface area represented by the PENELOPE phase space file and integrating the energies of the photons impacting within each pixel; a MATLAB code was written for this. The image contrast, signal to background ratio, spatial resolution, and collimation effect were calculated at the simulated detector as a function of pinhole diameter and various thicknesses of mask made of tungsten, tungsten/epoxy composite or bismuth alloy. A process of elimination was applied to identify suitable masks for a viable X-ray backscattering security application.

  16. Electron Paramagnetic Resonance Imaging

    Indian Academy of Sciences (India)

    IAS Admin

    principle behind imaging is to generate profiles of EPR spectra in presence of space-encoding linear field gradients oriented in all directions and uniformly distributed over the surface of a sphere centered on the object. We construct the image with filtered back projection, well known in ultrasound and computerized tomogra ...

  17. Monte Carlo simulation of electron depth distribution and backscattering for carbon films deposited on aluminium as a function of incidence angle and primary energy

    International Nuclear Information System (INIS)

    Dapor, Maurizio

    2005-01-01

    Carbon films are deposited on various substrates (polymers, polyester fabrics, polyester yarns, metal alloys) both for experimental and technological motivations (medical devices, biocompatible coatings, food package and so on). Computational studies of the penetration of electron beams in supported thin film of carbon are very useful in order to compare the simulated results with analytical techniques data (obtained by scanning electron microscopy and/or Auger electron spectroscopy) and investigate the film characteristics. In the present paper, the few keV electron depth distribution and backscattering coefficient for the special case of film of carbon deposited on aluminium are investigated, by a Monte Carlo simulation, as a function of the incidence angle and primary electron energy. The simulated results can be used as a way to evaluate the carbon film thickness by a set of measurements of the backscattering coefficient

  18. Structural evolution of a Ta-filament during hot-wire chemical vapour deposition of Silicon investigated by electron backscatter diffraction

    CSIR Research Space (South Africa)

    Oliphant, CJ

    2012-03-01

    Full Text Available microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and for the first time electron backscatter diffraction showed that various silicides form preferentially along the length of the filament. At the cooler filament ends the TaSi2 phase forms...

  19. 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.

  20. Effect of Welding Heat Input on Microstructure and Texture of Inconel 625 Weld Overlay Studied Using the Electron Backscatter Diffraction Method

    Science.gov (United States)

    Kim, Joon-Suk; Lee, Hae-Woo

    2016-12-01

    The grain size and the texture of three specimens prepared at different heat inputs were determined using optical microscopy and the electron backscatter diffraction method of scanning electron microscopy. Each specimen was equally divided into fusion line zone (FLZ), columnar dendrite zone (CDZ), and surface zone (SZ), according to the location of the weld. Fine dendrites were observed in the FLZ, coarse dendrites in the CDZ, and dendrites grew perpendicular to the FLZ and CDZ. As the heat input increased, the melted zone in the vicinity of the FLZ widened due to the higher Fe content. A lower image quality value was observed for the FLZ compared to the other zones. The results of grain size measurement in each zone showed that the grain size of the SZ became larger as the heat input increased. From the inverse pole figure (IPF) map in the normal direction (ND) and the rolling direction (RD), as the heat input increased, a specific orientation was formed. However, a dominant [001] direction was observed in the RD IPF map.

  1. Electron Paramagnetic Resonance Imaging

    Indian Academy of Sciences (India)

    IAS Admin

    NIH, USA. His research encompasses free radicals, redox biology of nitroxides,. CW- and FT-EPR imaging of tumor hypoxia, EPRI–MRI co- registration, etc. In this part we shall outline .... in the SPI mode we use a Cartesian raster where gradients are rastered systematically in a looped fashion about two or all the three axes ...

  2. Electron Paramagnetic Resonance Imaging

    Indian Academy of Sciences (India)

    IAS Admin

    MRI deals with the in vivo distribution of endogenous protons in water and tissue, whereas for EPRI we have to introduce bio- compatible free radicals before imaging. ..... no spectral information, but only spatial information. We can understand the spectral–spatial projections if we define a pseudo- viewing angle defined by.

  3. Electron Paramagnetic Resonance Imaging

    Indian Academy of Sciences (India)

    IAS Admin

    the signals are filtered through a TTE band-pass filter3 and further amplified using a low-noise amplifier4 and an RF-amplifier5. Adjustable attenuators are used in between amplification stages to set the appropriate signal levels and to avoid amplifier overload. The Free Induction Decay (FID) under imaging conditions ...

  4. 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

  5. Application of low-energy backscattered electron detection in the inspection of semiconductor devices technology

    Czech Academy of Sciences Publication Activity Database

    Hutař, Otakar; Oral, Martin; Müllerová, Ilona; Romanovský, Vladimír

    2000-01-01

    Roč. 45, č. 10 (2000), s. 271-272 ISSN 0447-6441 R&D Projects: GA AV ČR IBS2065017 Institutional research plan: CEZ:AV0Z2065902 Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  6. Angular and energy distribution of backscattered electrons simulated by Monte Carlo - assessment by experiment

    Czech Academy of Sciences Publication Activity Database

    Starý, V.; Zemek, Josef; Pavluch, J.

    2008-01-01

    Roč. 82, č. 2 (2008), 121-124 ISSN 0042-207X R&D Projects: GA AV ČR IAA100100622; GA ČR GA202/06/0459 Institutional research plan: CEZ:AV0Z10100521 Keywords : Monte - Carlo simulation * elastic electron reflection * elektron spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.114, year: 2008

  7. Aspects of electron acoustic wave physics in laser backscatter from plasmas

    International Nuclear Information System (INIS)

    Sircombe, N J; Arber, T D; 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 displaying both stimulated Raman and stimulated electron acoustic scattering. The amplitude of simulated EAWs is greater than that observed experimentally and is accompanied by a higher phase velocity. These minor differences can be attributed to the limitations of a one-dimensional collisionless model

  8. 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 –...

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

    International Nuclear Information System (INIS)

    Child, D.J.; West, G.D.; Thomson, R.C.

    2011-01-01

    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 Peenstress SM 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.

  10. An electron back-scattered diffraction study on the microstructure evolution of severely deformed aluminum AI6061 alloy

    Science.gov (United States)

    Vaseghi, M.; Karimi Taheri, A.; Kim, H. S.

    2014-08-01

    In this paper dynamic strain ageing behavior in an Al-Mg-Si alloy related to equal channel angular pressing (ECAP) was investigated. In order to examine the combined plastic deformation and ageing effects on microstructure evolutions and strengthening characteristics, the Al6061 alloy were subjected to phi=90° ECAP die for up to 4 passes via route Bc at high temperatures. For investigating the effects of ageing temperature and strain rate in ECAP, Vickers hardness tests were performed. The combination of the ECAP process with dynamic ageing at higher temperatures resulted in a significant increase in hardness. The microstructural evolution of the samples was studied using electron back-scattering diffraction (EBSD). The grains of Al6061 aluminum alloy were refined significantly at 100 and 150 °C with greater pass numbers and the distributions of grain size tended to be more uniform with pass number increasing. Frequency of sub-boundaries and low angle grain boundaries (LAGBs) increased at initial stage of deformation, and sub-boundaries and LAGBs evolved into highangle grain boundaries (HAGBs) with further deformation, which resulted in the high frequency of HAGBs in the alloy after ECAP 4 passes.

  11. Comparison of quartz crystallographic preferred orientations identified with optical fabric analysis, electron backscatter and neutron diffraction techniques.

    Science.gov (United States)

    Hunter, N J R; Wilson, C J L; Luzin, V

    2017-02-01

    Three techniques are used to measure crystallographic preferred orientations (CPO) in a naturally deformed quartz mylonite: transmitted light cross-polarized microscopy using an automated fabric analyser, electron backscatter diffraction (EBSD) and neutron diffraction. Pole figure densities attributable to crystal-plastic deformation are variably recognizable across the techniques, particularly between fabric analyser and diffraction instruments. Although fabric analyser techniques offer rapid acquisition with minimal sample preparation, difficulties may exist when gathering orientation data parallel with the incident beam. Overall, we have found that EBSD and fabric analyser techniques are best suited for studying CPO distributions at the grain scale, where individual orientations can be linked to their source grain or nearest neighbours. Neutron diffraction serves as the best qualitative and quantitative means of estimating the bulk CPO, due to its three-dimensional data acquisition, greater sample area coverage, and larger sample size. However, a number of sampling methods can be applied to FA and EBSD data to make similar approximations. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

  12. 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...

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

    International Nuclear Information System (INIS)

    Loew, Marjorie

    2006-01-01

    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)

  14. 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.)

  15. Direct electron imaging in electron microscopy with monolithic active pixel sensors

    Energy Technology Data Exchange (ETDEWEB)

    Deptuch, G. [Brookhaven National Laboratory, Upton, NY 11973 (United States)], E-mail: deptuch@ieee.org; Besson, A. [IPHC, CNRS-IN2P3/ULP, 23 rue du Loess, BP 28, 67037 Strasbourg Cedex 02 (France); Rehak, P. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Szelezniak, M. [IPHC, CNRS-IN2P3/ULP, 23 rue du Loess, BP 28, 67037 Strasbourg Cedex 02 (France); Wall, J. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Winter, M. [IPHC, CNRS-IN2P3/ULP, 23 rue du Loess, BP 28, 67037 Strasbourg Cedex 02 (France); Zhu, Y. [Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2007-08-15

    A new imaging device for dynamic electron microscopy is in great demand. The detector should provide the experimenter with images having sufficient spatial resolution at high speed. Immunity to radiation damage, accumulated during exposures, is critical. Photographic film, a traditional medium, is not adequate for studies that require large volumes of data or rapid recording and charge coupled device (CCD) cameras have limited resolution, due to phosphor screen coupling. CCD chips are not suitable for direct recording due to their extreme sensitivity to radiation damage. This paper discusses characterization of monolithic active pixel sensors (MAPS) in a scanning electron microscope (SEM) as well as in a transmission electron microscope (TEM). The tested devices were two versions of the MIMOSA V (MV) chip. This 1 M pixel device features pixel size of 17x17 {mu}m{sup 2} and was designed in a 0.6 {mu}m CMOS process. The active layer for detection is a thin (less than 20 {mu}m) epitaxial layer, limiting the broadening of the electron beam. The first version of the detector was a standard imager with electronics, passivation and interconnection layers on top of the active region; the second one was bottom-thinned, reaching the epitaxial layer from the bottom. The electron energies used range from a few keV to 30 keV for SEM and from 40 to 400 keV for TEM. Deterioration of the image resolution due to backscattering was quantified for different energies and both detector versions.

  16. Spatially coded backscatter radiography

    International Nuclear Information System (INIS)

    Thangavelu, S.; Hussein, E.M.A.

    2007-01-01

    Conventional radiography requires access to two opposite sides of an object, which makes it unsuitable for the inspection of extended and/or thick structures (airframes, bridges, floors etc.). Backscatter imaging can overcome this problem, but the indications obtained are difficult to interpret. This paper applies the coded aperture technique to gamma-ray backscatter-radiography in order to enhance the detectability of flaws. This spatial coding method involves the positioning of a mask with closed and open holes to selectively permit or block the passage of radiation. The obtained coded-aperture indications are then mathematically decoded to detect the presence of anomalies. Indications obtained from Monte Carlo calculations were utilized in this work to simulate radiation scattering measurements. These simulated measurements were used to investigate the applicability of this technique to the detection of flaws by backscatter radiography

  17. Comparison of Electron Imaging Modes for Dimensional Measurements in the Scanning Electron Microscope.

    Science.gov (United States)

    Postek, Michael T; Vladár, András E; Villarrubia, John S; Muto, Atsushi

    2016-08-01

    Dimensional measurements from secondary electron (SE) images were compared with those from backscattered electron (BSE) and low-loss electron (LLE) images. With the commonly used 50% threshold criterion, the lines consistently appeared larger in the SE images. As the images were acquired simultaneously by an instrument with the capability to operate detectors for both signals at the same time, the differences cannot be explained by the assumption that contamination or drift between images affected the SE, BSE, or LLE images differently. Simulations with JMONSEL, an electron microscope simulator, indicate that the nanometer-scale differences observed on this sample can be explained by the different convolution effects of a beam with finite size on signals with different symmetry (the SE signal's characteristic peak versus the BSE or LLE signal's characteristic step). This effect is too small to explain the >100 nm discrepancies that were observed in earlier work on different samples. Additional modeling indicates that those discrepancies can be explained by the much larger sidewall angles of the earlier samples, coupled with the different response of SE versus BSE/LLE profiles to such wall angles.

  18. Effects of Estimators on Ultrasound Nakagami Imaging in Visualizing the Change in the Backscattered Statistics from a Rayleigh Distribution to a Pre-Rayleigh Distribution.

    Science.gov (United States)

    Tsui, Po-Hsiang; Wan, Yung-Liang; Tai, Dar-In; Shu, Yu-Chen

    2015-08-01

    Ultrasound Nakagami imaging has recently attracted interest as an imaging technique for analyzing envelope statistics. Because the presence of structures has a strong effect on estimation of the Nakagami parameter, previous studies have indicated that Nakagami imaging should be used specifically for characterization of soft tissues with fewer structures, such as liver tissues. Typically, changes in the properties of the liver parenchyma cause the backscattered statistics to transform from a Rayleigh distribution to a pre-Rayleigh distribution, and this transformation can be visualized using a Nakagami imaging technique. However, different estimators result in different estimated values; thus, the performance of a Nakagami image may depend on the type of estimator used. This study explored the effects of various estimators on ultrasound Nakagami imaging to describe the backscattered statistics as they change from a Rayleigh distribution to a pre-Rayleigh distribution. Simulations and clinical measurements involving patients with liver fibrosis (n = 85) yielded image data that were used to construct B-mode and conventional Nakagami images based on the moment estimator (denoted as mINV images) and maximum-likelihood estimator (denoted as mML images). In addition, novel window-modulated compounding Nakagami images based on the moment estimator (denoted as mWMC images) were also obtained. The means and standard deviations of the Nakagami parameters were examined as a function of the backscattered statistics. The experimental results indicate that the mINV, mML and mWMC images enabled quantitative visualization of the change in backscattered statistics from a Rayleigh distribution to a pre-Rayleigh distribution. Importantly, the mWMC image is superior to both mINV and mML images because it simultaneously realizes sensitive detection of the backscattered statistics and a reduction of estimation variance for image smoothness improvement. We therefore recommend using m

  19. 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.

  20. 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.

  1. SU-C-209-05: Monte Carlo Model of a Prototype Backscatter X-Ray (BSX) Imager for Projective and Selective Object-Plane Imaging

    International Nuclear Information System (INIS)

    Rolison, L; Samant, S; Baciak, J; Jordan, K

    2016-01-01

    Purpose: To develop a Monte Carlo N-Particle (MCNP) model for the validation of a prototype backscatter x-ray (BSX) imager, and optimization of BSX technology for medical applications, including selective object-plane imaging. Methods: BSX is an emerging technology that represents an alternative to conventional computed tomography (CT) and projective digital radiography (DR). It employs detectors located on the same side as the incident x-ray source, making use of backscatter and avoiding ring geometry to enclose the imaging object. Current BSX imagers suffer from low spatial resolution. A MCNP model was designed to replicate a BSX prototype used for flaw detection in industrial materials. This prototype consisted of a 1.5mm diameter 60kVp pencil beam surrounded by a ring of four 5.0cm diameter NaI scintillation detectors. The imaging phantom consisted of a 2.9cm thick aluminum plate with five 0.6cm diameter holes drilled halfway. The experimental image was created using a raster scanning motion (in 1.5mm increments). Results: A qualitative comparison between the physical and simulated images showed very good agreement with 1.5mm spatial resolution in plane perpendicular to incident x-ray beam. The MCNP model developed the concept of radiography by selective plane detection (RSPD) for BSX, whereby specific object planes can be imaged by varying kVp. 10keV increments in mean x-ray energy yielded 4mm thick slice resolution in the phantom. Image resolution in the MCNP model can be further increased by increasing the number of detectors, and decreasing raster step size. Conclusion: MCNP modelling was used to validate a prototype BSX imager and introduce the RSPD concept, allowing for selective object-plane imaging. There was very good visual agreement between the experimental and MCNP imaging. Beyond optimizing system parameters for the existing prototype, new geometries can be investigated for volumetric image acquisition in medical applications. This material is

  2. Polarimetric imaging of turbid inhomogeneous slab media based on backscattering using a pencil beam for illumination: Monte Carlo simulation

    Science.gov (United States)

    Otsuki, Soichi

    2018-04-01

    Polarimetric imaging of absorbing, strongly scattering, or birefringent inclusions is investigated in a negligibly absorbing, moderately scattering, and isotropic slab medium. It was proved that the reduced effective scattering Mueller matrix is exactly calculated from experimental or simulated raw matrices even if the medium is anisotropic and/or heterogeneous, or the outgoing light beam exits obliquely to the normal of the slab surface. The calculation also gives a reasonable approximation of the reduced matrix using a light beam with a finite diameter for illumination. The reduced matrix was calculated using a Monte Carlo simulation and was factorized in two dimensions by the Lu-Chipman polar decomposition. The intensity of backscattered light shows clear and modestly clear differences for absorbing and strongly scattering inclusions, respectively, whereas it shows no difference for birefringent inclusions. Conversely, some polarization parameters, for example, the selective depolarization coefficients exhibit only a slight difference for the absorbing inclusions, whereas they showed clear difference for the strongly scattering or birefringent inclusions. Moreover, these quantities become larger with increasing the difference in the optical properties of the inclusions relative to the surrounding medium. However, it is difficult to recognize inclusions that buried at the depth deeper than 3 mm under the surface. Thus, the present technique can detect the approximate shape and size of these inclusions, and considering the depth where inclusions lie, estimate their optical properties. This study reveals the possibility of the polarization-sensitive imaging of turbid inhomogeneous media using a pencil beam for illumination.

  3. Three-Dimensional Backscatter X-Ray Imaging System, Phase I

    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...

  4. Three-Dimensional Backscatter X-Ray Imaging System, Phase II

    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. 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.

  6. 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.

  7. 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,...

  8. Image Resolution in Scanning Transmission Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pennycook, S. J.; Lupini, A.R.

    2008-06-26

    Digital images captured with electron microscopes are corrupted by two fundamental effects: shot noise resulting from electron counting statistics and blur resulting from the nonzero width of the focused electron beam. The generic problem of computationally undoing these effects is called image reconstruction and for decades has proved to be one of the most challenging and important problems in imaging science. This proposal concerned the application of the Pixon method, the highest-performance image-reconstruction algorithm yet devised, to the enhancement of images obtained from the highest-resolution electron microscopes in the world, now in operation at Oak Ridge National Laboratory.

  9. NOAA TIFF Image - 2m Backscatter Mosaic, W00216 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 the bathymetry of a sharply sloping swath of the St. John Shelf, St. John, USVI. NOAA's...

  10. 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...

  11. NOAA TIFF Image - 4m Backscatter Mosaic , W00216 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 4 meter resolution backscatter mosaic of of a sharply sloping swath of the St. John Shelf, south of St. John, US Virgin Islands. NOAA's...

  12. 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...

  13. 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...

  14. 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,...

  15. 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, in...

  16. NOAA TIFF Image - 1 m Backscatter Mosaic of an inshore 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 (NCEI Accession 0131860)

    Data.gov (United States)

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

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. NOAA TIFF Image - 4m Backscatter Mosaic , W00216 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 4 meter resolution backscatter mosaic of of a sharply sloping swath of the St. John Shelf, south of St. John, US Virgin Islands. NOAA's...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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 (NCEI Accession 0131860)

    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...

  16. 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...

  17. NOAA TIFF Image - 1 m Backscatter Mosaic of an inshore 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 the inshore portion of the NPS's Virgin Islands Coral Reef National Monument, south of St. John, US...

  18. NOAA TIFF Image - 2m Backscatter Mosaic, W00216 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 the bathymetry of a sharply sloping swath of the St. John Shelf, St. John, USVI. NOAA's...

  19. Scanning Electron Microscopy Sample Preparation and Imaging.

    Science.gov (United States)

    Nguyen, Jenny Ngoc Tran; Harbison, Amanda M

    2017-01-01

    Scanning electron microscopes allow us to reach magnifications of 20-130,000× and resolve compositional and topographical images with intense detail. These images are created by bombarding a sample with electrons in a focused manner to generate a black and white image from the electrons that bounce off of the sample. The electrons are detected using positively charged detectors. Scanning electron microscopy permits three-dimensional imaging of desiccated specimens or wet cells and tissues by using variable pressure chambers. SEM ultrastructural analysis and intracellular imaging supplement light microscopy for molecular profiling of prokaryotes, plants, and mammals. This chapter demonstrates how to prepare and image samples that are (a) desiccated and conductive, (b) desiccated and nonconductive but coated with an electron conductive film using a gold sputter coater, and (c) wet and maintained in a hydrated state using a Deben Coolstage.

  20. Image formation and image analysis in electron microscopy

    International Nuclear Information System (INIS)

    Heel, M. van.

    1981-01-01

    This thesis covers various aspects of image formation and image analysis in electron microscopy. The imaging of relatively strong objects in partially coherent illumination, the coherence properties of thermionic emission sources and the detection of objects in quantum noise limited images are considered. IMAGIC, a fast, flexible and friendly image analysis software package is described. Intelligent averaging of molecular images is discussed. (C.F.)

  1. 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...

  2. Coherent backscatter radar imaging in Brazil: large-scale waves in the bottomside F-region at the onset of equatorial spread F

    Directory of Open Access Journals (Sweden)

    F. S. Rodrigues

    2008-10-01

    Full Text Available The 30 MHz coherent backscatter radar located at the equatorial observatory in São Luís, Brazil (2.59° S, 44.21° W, −2.35° dip lat has been upgraded to perform coherent backscatter radar imaging. The wide field-of-view of this radar makes it well suited for radar imaging studies of ionospheric irregularities. Radar imaging observations were made in support to the spread F Experiment (SpreadFEx campaign. This paper describes the system and imaging technique and presents results from a bottom-type layer that preceded fully-developed radar plumes on 25 October 2005. The radar imaging technique was able to resolve decakilometric structures within the bottom-type layer. These structures indicate the presence of large-scale waves (~35 km in the bottomside F-region with phases that are alternately stable and unstable to wind-driven gradient drift instabilities. The observations suggest that these waves can also cause the initial perturbation necessary to initiate the Generalized Rayleigh-Taylor instability leading to spread F. The electrodynamic conditions and the scale length of the bottom-type layer structures suggest that the waves were generated by the collisional shear instability. These results indicate that monitoring bottom-type layers may provide helpful diagnostics for spread F forecasting.

  3. Fundamentals of electronic image processing

    CERN Document Server

    Weeks, Arthur R

    1996-01-01

    This book is directed to practicing engineers and scientists who need to understand the fundamentals of image processing theory and algorithms to perform their technical tasks. It is intended to fill the gap between existing high-level texts dedicated to specialists in the field and the need for a more practical, fundamental text on image processing. A variety of example images are used to enhance reader understanding of how particular image processing algorithms work.

  4. On the annealing behaviour of dysprosium ion implanted nickel: a combined study using Rutherford backscattering, transmission electron microscopy, and total current spectroscopy

    International Nuclear Information System (INIS)

    Chadderton, L.T.; Johnson, E.

    1977-01-01

    Despite continuing improvements in applications of the analytical method of Rutherford backscattering (RBS) to solid state physics it is recognized that more complete information can be obtained if other techniques - for example transmission electron microscopy (TEM) - are employed simultaneously. Experiments are described in which a combined RBS and TEM study of the annealing of nickel, rendered amorphous by implantation of 20 keV dysprosium ions is supplemented with a completely new technique - total current spectroscopy (TCS). In TCS low energy electrons (0-15 eV) are used to probe the damaged nickel. Observations have been made during annealing of both the reappearance of the bulk band structure of the metal and of a 'surface peak' which is highly sensitive to the recovery process. Changes in the height of the surface peak reveal three sharp annealing stages, the first two being preceded by reverse annealing which correlates well with RBS and TEM results. The first annealing stage - following the amorphous to crystalline transition - may be associated with electronic effects in the vicinity of the Curie point. Changes in the position of the surface peak allow one to trace the diffusion of dysprosium to the surface. Quantum mechanical resonances at the damage/crystal interface have also been followed throughout annealing. The initially amorphous layer (approximately 2.2nm) increases in thickness slightly during recovery. (Auth.)

  5. Combining pixel and object based image analysis of ultra-high resolution multibeam bathymetry and backscatter for habitat mapping in shallow marine waters

    Science.gov (United States)

    Ierodiaconou, Daniel; Schimel, Alexandre C. G.; Kennedy, David; Monk, Jacquomo; Gaylard, Grace; Young, Mary; Diesing, Markus; Rattray, Alex

    2018-01-01

    Habitat mapping data are increasingly being recognised for their importance in underpinning marine spatial planning. The ability to collect ultra-high resolution (cm) multibeam echosounder (MBES) data in shallow waters has facilitated understanding of the fine-scale distribution of benthic habitats in these areas that are often prone to human disturbance. Developing quantitative and objective approaches to integrate MBES data with ground observations for predictive modelling is essential for ensuring repeatability and providing confidence measures for habitat mapping products. Whilst supervised classification approaches are becoming more common, users are often faced with a decision whether to implement a pixel based (PB) or an object based (OB) image analysis approach, with often limited understanding of the potential influence of that decision on final map products and relative importance of data inputs to patterns observed. In this study, we apply an ensemble learning approach capable of integrating PB and OB Image Analysis from ultra-high resolution MBES bathymetry and backscatter data for mapping benthic habitats in Refuge Cove, a temperate coastal embayment in south-east Australia. We demonstrate the relative importance of PB and OB seafloor derivatives for the five broad benthic habitats that dominate the site. We found that OB and PB approaches performed well with differences in classification accuracy but not discernible statistically. However, a model incorporating elements of both approaches proved to be significantly more accurate than OB or PB methods alone and demonstrate the benefits of using MBES bathymetry and backscatter combined for class discrimination.

  6. Electron image reconstruction of helical protein assemblies

    International Nuclear Information System (INIS)

    Cremers, A.F.M.

    1980-01-01

    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.)

  7. 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

    2016-02-01

    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.

  8. Direct imaging detectors for electron microscopy

    Science.gov (United States)

    Faruqi, A. R.; McMullan, G.

    2018-01-01

    Electronic detectors used for imaging in electron microscopy are reviewed in this paper. Much of the detector technology is based on the developments in microelectronics, which have allowed the design of direct detectors with fine pixels, fast readout and which are sufficiently radiation hard for practical use. Detectors included in this review are hybrid pixel detectors, monolithic active pixel sensors based on CMOS technology and pnCCDs, which share one important feature: they are all direct imaging detectors, relying on directly converting energy in a semiconductor. Traditional methods of recording images in the electron microscope such as film and CCDs, are mentioned briefly along with a more detailed description of direct electronic detectors. Many applications benefit from the use of direct electron detectors and a few examples are mentioned in the text. In recent years one of the most dramatic advances in structural biology has been in the deployment of the new backthinned CMOS direct detectors to attain near-atomic resolution molecular structures with electron cryo-microscopy (cryo-EM). The development of direct detectors, along with a number of other parallel advances, has seen a very significant amount of new information being recorded in the images, which was not previously possible-and this forms the main emphasis of the review.

  9. The Scanning Electron Microscope and the Archaeologist

    Science.gov (United States)

    Ponting, Matthew

    2004-01-01

    Images from scanning electron microscopy are now quite common and they can be of great value in archaeology. Techniques such as secondary electron imaging, backscattered electron imaging and energy-dispersive x-ray analysis can reveal information such as the presence of weevils in grain in Roman Britain, the composition of Roman coins and the…

  10. Cellular imaging electron tomography and related techniques

    CERN Document Server

    2018-01-01

    This book highlights important techniques for cellular imaging and covers the basics and applications of electron tomography and related techniques. In addition, it considers practical aspects and broadens the technological focus by incorporating techniques that are only now becoming accessible (e.g. block face imaging).  The first part of the book describes the electron microscopy 3D technique available to scientists around the world, allowing them to characterize organelles, cells and tissues. The major emphasis is on new technologies like scanning transmission electron microscopy (STEM) tomography, though the book also reviews some of the more proven technologies like electron tomography. In turn, the second part is dedicated to the reconstruction of data sets, signal improvement and interpretation.

  11. 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.

  12. Electron Holography Image Simulation of Nanoparticles

    NARCIS (Netherlands)

    Keimpema, K.; Raedt, H. De; Hosson, J.Th.M. De

    We discuss a real-space and a Fourier-space technique to compute numerically, the phase images observed by electron holography of nanoscale particles. An assessment of the applicability and accuracy of these techniques is made by calculating numerical results for simple geometries for which

  13. Electronic Imaging in Astronomy Detectors and Instrumentation

    CERN Document Server

    McLean, Ian

    2008-01-01

    The second edition of Electronic Imaging in Astronomy: Detectors and Instrumentation describes the remarkable developments that have taken place in astronomical detectors and instrumentation in recent years – from the invention of the charge-coupled device (CCD) in 1970 to the current era of very large telescopes, such as the Keck 10-meter telescopes in Hawaii with their laser guide-star adaptive optics which rival the image quality of the Hubble Space Telescope. Authored by one of the world’s foremost experts on the design and development of electronic imaging systems for astronomy, this book has been written on several levels to appeal to a broad readership. Mathematical expositions are designed to encourage a wider audience, especially among the growing community of amateur astronomers with small telescopes with CCD cameras. The book can be used at the college level for an introductory course on modern astronomical detectors and instruments, and as a supplement for a practical or laboratory class.

  14. Transit Dosimetry for Patient Treatment Verification with an Electronic Portal Imaging Device

    Science.gov (United States)

    Berry, Sean L.

    The complex and individualized photon fluence patterns constructed during intensity modulated radiation therapy (IMRT) treatment planning must be verified before they are delivered to the patient. There is a compelling argument for additional verification throughout the course of treatment due to the possibility of data corruption, unintentional modification of the plan parameters, changes in patient anatomy, errors in patient alignment, and even mistakes in identifying the correct patient for treatment. Amorphous silicon (aSi) Electronic Portal Imaging Devices (EPIDs) can be utilized for IMRT verification. The goal of this thesis is to implement EPID transit dosimetry, measurement of the dose at a plane behind the patient during their treatment, within the clinical process. In order to achieve this goal, a number of the EPID's dosimetric shortcomings were studied and subsequently resolved. Portal dose images (PDIs) acquired with an aSi EPID suffer from artifacts related to radiation backscattered asymmetrically from the EPID support structure. This backscatter signal varies as a function of field size (FS) and location on the EPID. Its presence can affect pixel values in the measured PDI by up to 3.6%. Two methods to correct for this artifact are offered: discrete FS specific correction matrices and a single generalized equation. The dosimetric comparison between the measured and predicted through-air dose images for 49 IMRT treatment fields was significantly improved (p impact of transit dosimetry on the clinical workflow for these nine patients was analyzed to identify improvements that could be made to the procedure in order to ease widespread clinical implementation. EPID transit dosimetry is a worthwhile treatment verification technique that strikes a balance between effectiveness and efficiency. This work, which focused on the removal of backscattered radiation artifacts, verification of the EPID's stability with gantry rotation, and the formulation and

  15. The potential of materials analysis by electron Rutherford backscattering as illustrated by a case study of mouse bones and related compounds

    International Nuclear Information System (INIS)

    Vos, M.; Toekesi, K.; Benkoe, I.

    2012-01-01

    Complete text of publication follows. Electron Rutherford backscattering (ERBS) has a number of distinct advantages for semi-quantitative analysis of samples. These are for example: a) Its high energy makes it rather insensitive to surface effects. b) The peaks appear well approximated by Gaussian with no obvious problems due to background subtraction. c) All the electrons involved have very similar kinetic energy, and hence one does not need to consider changes of the mean-free path or the analyzer transmission function. d) There are no intrinsic satellites to complicate the quantitative interpretation. On the other hand ERBS has a weak point, peaks tend to overlap. Peak separation is proportional to the incoming energy E0, but the intrinsic peak width increases proportional to the square root of E 0 . In practice one has to live with overlapping peaks. In the present work we mainly focus on the measurement and analysis procedure, and compare our best estimate of the concentration of the various elements in mouse bone with that obtained in a recent paper. The promise of ERBS as an analytical technique is clear from the successful analysis of the simple case of calcium carbonate and the somewhat more complicated case of hydroxyapatite. Here agreement between the measured and actual composition are on a very respectable 10% level. The actual bone sample showed more variation in outcome and a somewhat less satisfactory agreement between experiment and theory (see Fig. 1). The variation in outcome between the different measurements can be due to the fact that we average over very few grains, and that the grain composition will vary somewhat with its original position in the bone. In summary, ERBS can become a useful tool to study bone mineralization. As our knowledge of bone mineralization is incomplete this is currently an active topic of multidisciplinary research involving people working in physics, chemistry and biological/medical sciences. One of the important

  16. An electron backscattered diffraction study on the dynamic recrystallization behavior of a nickel–chromium alloy (800H) during hot deformation

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Yu, E-mail: vieri32825@126.com [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Di, Hongshuang; Zhang, Jingqi; Zhang, Jiecen; Ma, Tianjun [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Misra, R.D.K. [Center for Structural and Functional Materials, University of Louisiana at Lafayette, P.O. Box 44130, LA 70503 (United States)

    2013-11-15

    The objective of the study described here is to evaluate the effect of temperature, strain rate, and strain on the microstructure of dynamically recrystallized nickel–chromium alloy (800H) subjected to hot compression over a wide range of strain rates. The microstructural evolution was studied by electron backscattered diffraction (EBSD) and the effect of adiabatic heating on hot deformation was analyzed to correct the flow curves at high strains. The grain orientation spread (GOS) approach was used to distinguish the dynamic recrystallization (DRX) grains from the deformed matrix. The nucleation mechanism of DRX and the role of Σ3{sup n} CSL boundaries during DRX were explored. Additionally, the influence of carbides on the DRX behavior was studied within the temperature of 850–950 °C. The results indicated that the DRX can be stimulated by adiabatic heating and strong dislocation–dislocation interaction occurring with increase in the strain rate in the range of 1–30 s{sup −1}. The threshold value of GOS (1.2°) separated the DRX grains from the deformed matrix. The recrystallized grains nucleated at pre-existing grain boundaries by extensive bulging associated with grain fragmentation. The Σ3{sup n} CSL boundaries play an important role in DRX and they can be generated through interaction among them after the initiation of DRX. The precipitation of Cr{sub 23}C{sub 6} and Ti(C, N) at the parent grain boundary could restrain or even inhibit the occurrence of DRX in the temperature range of 850–950 °C.

  17. Investigation of fatigue crack initiation facets in Ti-6Al-4V using focused ion beam milling and electron backscatter diffraction.

    Science.gov (United States)

    Everaerts, J; Verlinden, B; Wevers, M

    2017-07-01

    In the very high cycle fatigue regime, internal crack initiation can occur in Ti-6Al-4V because of the formation of facets, which are α grains that have fractured in a transcrystalline and planar manner. Because this crack initiation phase occupies most of the fatigue life, it is essential to understand which mechanisms lead to facet formation. Fatigue tests have been performed on drawn and heat-treated Ti-6Al-4V wires, and the facets at internal crack initiation sites have been analysed in detail in terms of their appearance, their spatial orientation and their crystallographic orientation. The facets were not smooth, but showed surface markings at the nanoscale. In nearly all cases, these markings followed a linear pattern. One anomalous facet, in a sample with the largest grain size, contained a fan-shaped pattern. The facets were at relatively steep angles, mostly between 50° and 70°. Cross-sections of the fracture surfaces have been made by focused ion beam milling and were used to measure the crystallographic orientation of facets by electron backscatter diffraction. Most facet planes coincided with a prismatic lattice plane, and the linear markings were parallel to the prismatic slip direction, which is a strong indication that prismatic slip and slip band formation led to crack initiation. However, the anomalous facet had a near-basal orientation, which points to a possible cleavage mechanism. The cross-sections also exposed secondary cracks, which had formed on prismatic lattice planes, and in some cases early stage facet formation and short crack growth phenomena. The latter observations show that facets can extend through more than one grain, and that there is crack coalescence between facets. The fact that drawn wires have a specific crystallographic texture has led to a different facet formation behaviour compared to what has been suggested in the literature. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  18. 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.

  19. Effects of electron back-scattering in observations of cross-sectioned GaAs/AlAs superlattice with auger electron spectroscopy.

    Science.gov (United States)

    Suzuki, Mineharu; Urushihara, Nobuaki; Sanada, Noriaki; Paul, Dennis F; Bryan, Scott; Hammond, John S

    2010-01-01

    Cross-sections of GaAs/AlAs thin films prepared by cleavage of MBE-grown superlattices have been analyzed with Auger electron spectroscopy with a spatial resolution of 6 nm. Elemental distributions of Ga, Al, and As were clearly distinguished in line analysis as well as in two dimensional mapping for 50, 20, and 10 nm thin film structures. We have found an oscillation of Al KLL peak position between the two values while the peak positions of Ga LMM and As LMM remain constant. The origin of the Al KLL peak shift is a primary electron beam induced reduction of oxidized Al atoms formed during specimen preparation. The Auger spectra of Al oxide are generated by scattered electrons at regions with small amounts of electron dose, corresponding to AlAs areas further than 10 to 25 nm from the primary beam. The intensity of the Al KLL peaks excited by scattered electrons from the 25 kV primary electron beam is about 10% of the Ga LMM peak intensity originating from the GaAs stripe.

  20. Imaging Electrons in Ultra-thin Nanowires

    Science.gov (United States)

    Boyd, Erin E.

    2011-12-01

    Ultra-thin semiconductor nanowires are promising systems in which to explore novel low-dimensional physics and are attractive candidates for future nanoelectronics. Ultra-thin nanowires with diameters of 20 to 30 nm are essentially one-dimensional (ID) for moderate electron number, because only one radial subband is occupied. Low-temperature scanning gate microscopy is especially well suited for improving our understanding of nanowires in order to optimize the construction of nanowire systems. We use a home-built liquid-He cooled scanning gate microscope (SGM) to probe and manipulate electrons beneath the surface of devices. The SGM's conductance images are obtained by scanning the charged SGM tip above the sample and recording the change in conductance through the device as a function of tip position. We present simulations of extracting the amplitude of the 1D electron wavefunction along the length of the quantum dot in an ultra-thin InAs/InP heterostructure nanowire (diameter = 30 nm) using a SGM. A weakly perturbing SGM tip slightly dents the electron wavefunction inside the quantum dot, and we propose measuring the change in energy of the dot due to the perturbation as a function of tip position. By measuring the change in energy of the dot and by knowing the form of the tip potential, the amplitude of the wavefunction can be found. This extraction technique could serve as a powerful tool to improve our understanding of electron behavior in quasi-1 D systems. We have used our SGM to image the conductance through an ultra-thin (diameter ˜ 30 nm) 1nAs nanowire with two InP barriers. Our imaging technique provides detailed information regarding the position and flow of electrons in the nanowire. We demonstrate that the charged SPM tip's position or voltage can be used to control the number of electrons on the quantum dots. We spatially locate three quantum dots in series along the length of the ultra-thin nanowire. Using energy level spectroscopy and the

  1. SU-E-J-176: Results of Images Acquired with Backscattered MV Radiation Using a Pinhole Collimator

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, D; Turian, J; Wu, Z; Darwish, N; Chu, J; Bernard, D [Rush University Medical Center, Chicago, IL (United States)

    2014-06-01

    Purpose: To ascertain the feasibility of acquiring real time images of small lung tumors from scattered photons while undergoing radiation treatment.There are several methodologies currently used to track tumor location such as MV-cine acquisition and kV fluoroscopy. However, MVcine offers no information parallel to the beam axis while kV fluoroscopy offers little potential for soft tissue discernability while also increasing the patient dose. This study investigates the feasibility of observing an actual simulated tumor while exploring techniques that may improve image quality. Methods: A prototype imager consisting of a gamma camera pinhole collimator and a computed radiography (CR) plate were used in conjunction with a Varian TrueBeam linac. One study consisted of a 2.5 cm diameter solid water cylinder representing a solid tumor imbedded within a lung equivalent material slab. The cylinder with the lung slab was sandwiched between 1 cm lung equivalent slabs and these were sandwiched between 2 slabs of solid water. The top water slab was 1 cm thick. The other imaging study consisted of three different density plugs, 0.46, 1.09, and 1.82 g/cm3 placed on the accelerator couch. The gantry was orientated 70° relative to the CR plate. The slabs and plugs were irradiated with 2000 MU and 500 MU respectively using the 6FFF mode. Results: The solid water plug was visually discernible in the slab phantom. The ratio of the signal coming from the higher density plugs (placed on the treatment couch) to that between the plugs increased from 1.02 to about 3.0 after subtracting the background image acquired with no plugs present. Conclusion: Preliminary results indicate that a lung tumor could be visualized with scattered radiation during treatment. Improvements in discerning an object can be enhanced by filtering out the head leakage and background scattered radiation not emanating from the imaged object.

  2. Rutherford Backscattering Spectrometry

    International Nuclear Information System (INIS)

    Gyulai, J.

    1981-02-01

    The bases of Rutherford ion backscattering and its combination with channeling effect technique are reviewed. This combined method is recently referred to as Backscattering Spectrometry. The measurement of chemical compositions, the detection of crystal defects etc are dealt with. Comparison with other surface analysis methods is also given. The review was delivered as a lecture during the ''International School for Surface Physics'' (Varna, Bulgaria, Sep 18 - Oct 20, 1980). (author)

  3. 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.

  4. Advances in imaging and electron physics time resolved electron diffraction for chemistry, biology and material science

    CERN Document Server

    Hawkes, Peter W

    2014-01-01

    Advances in Imaging & Electron Physics merges two long-running serials-Advances in Electronics & Electron Physics and Advances in Optical & Electron Microscopy. The series features 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. Contributions from leading authorities Informs and updates on all the latest developments in the field.

  5. 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. © The Author 2015. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. An Automatic Target Detection Algorithm for Swath Sonar Backscatter Imagery, Using Image Texture and Independent Component Analysis

    Directory of Open Access Journals (Sweden)

    Elias Fakiris

    2016-04-01

    Full Text Available In the present paper, a methodological scheme, bringing together common Acoustic Seabed Classification (ASC systems and a powerful data decomposition approach, called Independent Component Analysis (ICA, is demonstrated regarding its suitability for detecting small targets in Side Scan Sonar imagery. Traditional ASC systems extract numerous texture descriptors, leading to a large feature vector, the dimensionality of which is reduced by means of data decomposition techniques, usually Principal Component Analysis (PCA, prior to classification. However, in the target detection issue, data decomposition should point towards finding components that represent sub-ordinary image information (i.e., small targets rather than a dominant one. ICA has long been proved to be suitable for separating targets from a background, and this study represents a novel exhibition of its applicability to Side Scan Sonar (SSS images. The present study attempts to build a fully automated target detection approach that combines image based feature extraction, ICA, and unsupervised classification. The suitability of the proposed approach has been demonstrated using an SSS data-set containing more than 70 manmade targets, most of them metallic, validated through a marine magnetic survey or ground truthing inspection. The method exhibited very good performance as it was able to detect more than 77% of the targets and it produced less than seven false alarms per km2. Moreover, it was compared to cases where, in the exact same methodological scheme, no decomposition technique is used, or PCA is employed instead of ICA, achieving the highest detection rate, but, more importantly, producing more than six times less false alarms, thus proving that ICA successfully manages to maximize target to background separation.

  7. 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 Atlantic...

  8. 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,...

  9. 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,...

  10. 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...

  11. NOAA TIFF Image - 3m Backscatter Mosaic, Florida Deep Coral Areas (Jacksonville) - 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 Coast...

  12. 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 of...

  13. NOAA TIFF Image - Backscatter - Lang Bank, St. Croix, USVI - Benthic Habitat Characterization - NOAA Ship Nancy Foster - M-1907-NF-14 (2014), UTM 20N NAD83

    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. The...

  14. 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

  15. 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. © 2015 Wiley Periodicals, Inc.

  16. 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.

  17. 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...

  18. 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...

  19. Card controlled beta backscatter thickness measuring instrument

    International Nuclear Information System (INIS)

    Schlesinger, J.

    1978-01-01

    An improved beta backscatter instrument for the nondestructive measurement of the thickness of thin coatings on a substrate is described. Included therein is the utilization of a bank of memory stored data representative of isotope, substrate, coating material and thickness range characteristics in association with a control card having predetermined indicia thereon selectively representative of a particular isotope, substrate material, coating material and thickness range for conditioning electronic circuit means by memory stored data selected in accord with the predetermined indicia on a control card for converting backscattered beta particle counts into indicia of coating thickness

  20. 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.

  1. 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.

  2. 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

  3. Initial backscatter occurrence statistics from the CUTLASS HF radars

    Directory of Open Access Journals (Sweden)

    S. E. Milan

    Full Text Available A statistical study of the occurrence of ground and ionospheric backscatter within the fields-of-view of the CUTLASS HF radars, at an operating frequency of 10 MHz, during the first 20 months of operation has been undertaken. The diurnal variation of the occurrence of backscatter and the range at which such backscatter is observed is found to be highly dependent on seasonal changes of the ionospheric electron density in both the E and F region, determined from ionosonde observations. In general, ionospheric backscatter is observed at far ranges during the local day in winter months and at near ranges during the local night in summer months. The Iceland radar observes more near-range E region backscatter than the Finland radar as a consequence of its more zonal look-direction. The dependence of the occurrence of backscatter on geomagnetic activity and radar operating frequency are also investigated. The occurrence of ground and ionospheric backscatter is discussed in terms of HF propagation modes and ionospheric electron densities as well as geophysical processes. A brief assessment of the possible impact of solar cycle variations on the observations is made and frequency management is discussed. Such a study, with its focus on the `instrumental' aspect of backscatter occurrence, is essential for a full interpretation of HF coherent radar observations.

  4. 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

  5. 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.

  6. Low energy electron imaging using Medipix 2 detector

    NARCIS (Netherlands)

    Sikharulidze, I.; van Gastel, Raoul; Schramm, S.; Abrahams, J.P.; Poelsema, Bene; Tromp, R.M.; van der Molen, S.J.

    2011-01-01

    Low Energy Electron Microscopy (LEEM) and Photo-Emission Electron Microscopy (PEEM) predominantly use a combination of microchannel plate (MCP), phosphor screen and optical camera to record images formed by 10–20 keV electrons. We have tested the performance of a LEEM/PEEM instrument with a Medipix2

  7. Imaging differential polarization microscope with electronic readout

    International Nuclear Information System (INIS)

    Mickols, W.; Tinoco, I.; Katz, J.E.; Maestre, M.F.; Bustamante, C.

    1985-01-01

    A differential polarization microscope forms two images: one of the transmitted intensity and the other due to the change in intensity between images formed when different polarizations of light are used. The interpretation of these images for linear dichroism and circular dichroism are described. The design constraints on the data acquisition systems and the polarization modulation are described. The advantage of imaging several biological systems which contain optically anisotropic structures are described

  8. Angularly-selective transmission imaging in a scanning electron microscope.

    Science.gov (United States)

    Holm, Jason; Keller, Robert R

    2016-08-01

    This work presents recent advances in transmission scanning electron microscopy (t-SEM) imaging control capabilities. A modular aperture system and a cantilever-style sample holder that enable comprehensive angular selectivity of forward-scattered electrons are described. When combined with a commercially available solid-state transmission detector having only basic bright-field and dark-field imaging capabilities, the advances described here enable numerous transmission imaging modes. Several examples are provided that demonstrate how contrast arising from diffraction to mass-thickness can be obtained. Unanticipated image contrast at some imaging conditions is also observed and addressed. Published by Elsevier B.V.

  9. A fast and reliable approach to simulating the output from an x-ray tube used for developing security backscatter imaging

    Science.gov (United States)

    Vella, A.; Munoz, A.; Healy, M. J. F.; Lane, D. W.; Lockley, D.; Zhou, J.

    2017-08-01

    The PENELOPE Monte Carlo simulation code was used alongside the SpekCalc code to simulate X-ray energy spectra from a VJ Technologies' X-ray generator at a range of anode voltages. The PENELOPE code is often utilised in medicine but is here applied to develop coded aperture and pinhole imaging systems for security purposes. The greater computational burden of PENELOPE over SpekCalc is warranted by its greater flexibility and output information. The model was designed using the PENGEOM sub-tool and consists of a tungsten anode and five layers of window materials. The photons generated by a mono-energetic electron beam are collected by a virtual detector placed after the last window layer, and this records the spatial, angular and energy distributions which are then used as the X-ray source for subsequent simulations. The process of storing X-ray outputs and using them as a virtual photon source can then be used efficiently for exploring a range of imaging conditions as the computationally expensive electron interactions in the anode need not be repeated. The modelled spectra were validated with experimentally determined spectra collected with an Amptek X-123 Cadmium Telluride detector placed in front of the source.

  10. Imaging electron flow from collimating contacts in graphene

    Science.gov (United States)

    Bhandari, S.; Lee, G. H.; Watanabe, K.; Taniguchi, T.; Kim, P.; Westervelt, R. M.

    2018-04-01

    The ballistic motion of electrons in graphene opens exciting opportunities for electron-optic devices based on collimated electron beams. We form a collimating contact in a hBN-encapsulated graphene hall bar by adding zigzag contacts on either side of an electron emitter that absorb stray electrons; collimation can be turned off by floating the zig-zag contacts. The electron beam is imaged using a liquid-He cooled scanning gate microscope (SGM). The tip deflects electrons as they pass from the collimating contact to a receiving contact on the opposite side of the channel, and an image of electron flow can be made by displaying the change in transmission as the tip is raster scanned across the sample. The angular half width Δθ of the electron beam is found by applying a perpendicular magnetic field B that bends electron paths into cyclotron orbits. The images reveal that the electron flow from the collimating contact drops quickly at B  =  0.05 T when the electron orbits miss the receiving contact. The flow for the non-collimating case persists longer, up to B  =  0.19 T, due to the broader range of entry angles. Ray-tracing simulations agree well with the experimental images. By fitting the fields B at which the magnitude of electron flow drops in the experimental SGM images, we find Δθ  =  9° for electron flow from the collimating contact, compared with Δθ  =  54° for the non-collimating case.

  11. Compton backscattering axial spectrometer

    International Nuclear Information System (INIS)

    Rad'ko, V.E.; Mokrushin, A.D.; Razumovskaya, I.V.

    1981-01-01

    Compton gamma backscattering axial spectrometer of new design with the 200 time larger aperture as compared with the known spectrometers at the equal angular resolution (at E=159 keV) is described. Collimator unit, radiation source and gamma detector are located in the central part of the spectrometer. The investigated specimen (of cylindrical form) and the so called ''black body'' used for absorption of photons, passed through the specimen are placed in the peripheric part. Both these parts have an imaginary symmetry axis that is why the spectrometer is called axial. 57 Co is used as the gamma source. The 122 keV spectral line which corresponds to the 83 keV backscattered photon serves as working line. Germanium disk detector of 10 mm diameter and 4 mm height has energy resolution not worse than 900 eV. The analysis of results of test measurements of compton water profile and their comparison with data obtained earlier show that only finity of detector resolution can essentially affect the form of Compton profile. It is concluded that the suggested variant of the spectrometer would be useful for determination of Compton profiles of chemical compounds of heavy elements [ru

  12. High energy electron multibeam diffraction and imaging

    International Nuclear Information System (INIS)

    Bourret, Alain.

    1980-04-01

    The different theories of dynamical scattering of electrons are firstly reviewed with special reference to their basis and the validity of the different approximations. Then after a short description of the different experimental set ups, structural analysis and the investigation of the optical potential by means of high energy electrons will be surveyed

  13. Coincidence imaging system with electron optics

    Czech Academy of Sciences Publication Activity Database

    Kroupa, M.; Jakubek, J.; Krejčí, F.; Žemlička, J.; Horáček, Miroslav; Radlička, Tomáš; Vlček, Ivan

    2011-01-01

    Roč. 633, Supl. 1 (2011), S270-S273 ISSN 0168-9002 R&D Projects: GA AV ČR IAA100650803 Institutional research plan: CEZ:AV0Z20650511 Keywords : electron optics * coincidence Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.207, year: 2011

  14. A Micropulse eye-safe all-fiber molecular backscatter coherent temperature lidar

    DEFF Research Database (Denmark)

    Abari, Cyrus F.; Chu, Xinzhao; Mann, Jakob

    2016-01-01

    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...... 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....

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

    International Nuclear Information System (INIS)

    Taniguchi, Yoshifumi; Matsumoto, Hiroaki; Harada, Ken

    2012-01-01

    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.

  16. 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.

  17. 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.

  18. Advances in imaging and electron physics the scanning transmission electron microscope

    CERN Document Server

    Hawkes, Peter W

    2009-01-01

    Advances in Imaging and Electron Physics merges two long-running serials--Advances in Electronics and Electron Physics and Advances in Optical and Electron Microscopy. This series features 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.  This particular volume presents several timely articles on the scanning transmission electron microscope. Updated with contributions from leading international scholars and industry experts Discusses hot topic areas and presents current and future research trends Provides an invaluable reference and guide for physicists, engineers and mathematicians.

  19. Simulation study of secondary electron images in scanning ion microscopy

    CERN Document Server

    Ohya, K

    2003-01-01

    The target atomic number, Z sub 2 , dependence of secondary electron yield is simulated by applying a Monte Carlo code for 17 species of metals bombarded by Ga ions and electrons in order to study the contrast difference between scanning ion microscopes (SIM) and scanning electron microscopes (SEM). In addition to the remarkable reversal of the Z sub 2 dependence between the Ga ion and electron bombardment, a fine structure, which is correlated to the density of the conduction band electrons in the metal, is calculated for both. The brightness changes of the secondary electron images in SIM and SEM are simulated using Au and Al surfaces adjacent to each other. The results indicate that the image contrast in SIM is much more sensitive to the material species and is clearer than that for SEM. The origin of the difference between SIM and SEM comes from the difference in the lateral distribution of secondary electrons excited within the escape depth.

  20. Electronic imaging applied to neutron radiography

    International Nuclear Information System (INIS)

    Garrett, D.A.; Bracher, D.A.

    1976-01-01

    A commercially - available image intensifier was used with a scan conversion memory and a mobile 252 Cf based neutron radiography system to obtain neutron radiographs on a television monitor in 0.5 minutes to 10.0 minutes

  1. Ultrafast Imaging of Electronic Motion in Atoms and Molecules

    Science.gov (United States)

    2016-01-12

    AFRL-AFOSR-VA-TR-2016-0045 Ultrafast Imaging of Electronic Motion in Atoms and Molecules Martin Centurion UNIVERSITY OF NEBRSKA Final Report 01/12...Ultrafast Imaging of Electronic Motion in Atoms and Molecules 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-12-1-0149 5c. PROGRAM ELEMENT NUMBER 6...a gaseous target of atoms or molecules. An optical setup was designed and constructed to compensate for the blurring of the temporal resolution due

  2. On the Progress of Scanning Transmission Electron Microscopy (STEM) Imaging in a Scanning Electron Microscope.

    Science.gov (United States)

    Sun, Cheng; Müller, Erich; Meffert, Matthias; Gerthsen, Dagmar

    2018-03-28

    Transmission electron microscopy (TEM) with low-energy electrons has been recognized as an important addition to the family of electron microscopies as it may avoid knock-on damage and increase the contrast of weakly scattering objects. Scanning electron microscopes (SEMs) are well suited for low-energy electron microscopy with maximum electron energies of 30 keV, but they are mainly used for topography imaging of bulk samples. Implementation of a scanning transmission electron microscopy (STEM) detector and a charge-coupled-device camera for the acquisition of on-axis transmission electron diffraction (TED) patterns, in combination with recent resolution improvements, make SEMs highly interesting for structure analysis of some electron-transparent specimens which are traditionally investigated by TEM. A new aspect is correlative SEM, STEM, and TED imaging from the same specimen region in a SEM which leads to a wealth of information. Simultaneous image acquisition gives information on surface topography, inner structure including crystal defects and qualitative material contrast. Lattice-fringe resolution is obtained in bright-field STEM imaging. The benefits of correlative SEM/STEM/TED imaging in a SEM are exemplified by structure analyses from representative sample classes such as nanoparticulates and bulk materials.

  3. 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.

  4. Radiation imaging with glass gas electron multipliers (G -GEMs)

    Science.gov (United States)

    Fujiwara, Takeshi; Mitsuya, Yuki; Takahashi, Hiroyuki

    2018-01-01

    This review investigates the advantages and disadvantages of gaseous radiation detectors when compared with solid-state detectors, for use in radiation imaging, which are caused by the differing properties of gases and solids. Imaging applications for which micro-pattern gas detectors (MPGDs) are superior, include neutron imaging, high-linear-energy-transfer (LET) radiation imaging, and low-energy-depositing radiation imaging. This paper is focused on these applications where MPGDs, in particular, the glass gas electron multiplier (G-GEM), are superior, and their development is described and relevant experimental results are discussed.

  5. Quantitative characterization of abyssal seafloor with transit multibeam backscatter data

    Science.gov (United States)

    Pockalny, R. A.; Ferrini, V. L.

    2014-12-01

    The expanding volume of deep-water multibeam echosounder data provides emerging opportunities for the improved characterization of the abyssal seafloor. Nearly 500 cruises criss-cross the oceans with modern wide-swath multibeam systems, and these cruise tracks have imaged a variety of morphologic, tectonic and magmatic environments. The qualitative analysis of the seafloor backscatter data strongly suggests a local and regional variability that correlates with sediment thickness, sediment type and/or depositional environment. We present our initial attempts to develop a method that quantifies this observed seafloor backscatter variability and to explore the causes and potential implications of this variability. Our approach is rooted in the Angular Range Analysis methodology, which utilizes changes in backscatter amplitude observed as a function of grazing angle, to characterize the seafloor. The primary difference in our approach is that we do not invert for geo-acoustical parameters, but rather explores empirical relationships between geological observations and stacked slope and y-intercept values. In addition, we also include the mean and the variance of detrended backscatter measurements. Our initial results indicate intriguing relationships between backscatter parameters and the CaCO3 content of surface sediments. Seafloor regions reported to have high manganese nodule concentrations also tend to have characteristic trends in backscatter parameters. We will present these regional correlations as well as some preliminary statistical analyses of the backscatter parameters and key environmental factors.

  6. Electron accelerating unit for streak image tubes

    Indian Academy of Sciences (India)

    Keywords. High-speed photography; streak camera; Monte Carlo; electro-optical devices. 1. Introduction. Streak cameras are among the most valuable instruments for recording ultrafast phenomena in laser-driven inertial confinement fusion (ICF) experiments, and streak image tubes (SITs) are a core part of streak cameras.

  7. [Electronic Device for Retinal and Iris Imaging].

    Science.gov (United States)

    Drahanský, M; Kolář, R; Mňuk, T

    This paper describes design and construction of a new device for automatic capturing of eye retina and iris. This device has two possible ways of utilization - either for biometric purposes (persons recognition on the base of their eye characteristics) or for medical purposes as supporting diagnostic device. eye retina, eye iris, device, acquisition, image.

  8. 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

  9. A fast iterative technique for restoring scanning electron microscope images

    Energy Technology Data Exchange (ETDEWEB)

    Nakahira, Kenji, E-mail: kenji.nakahira.kp@hitachi.com; Miyamoto, Atsushi; Honda, Toshifumi

    2014-12-21

    This paper proposes a fast new technique for restoring scanning electron microscope images to improve their sharpness. The images with our approach are sharpened by deconvolution with the point spread function modeled as the intensity distribution of the electron beam at the specimen's surface. We propose an iterative technique that employs a modified cost function based on the Richardson–Lucy method to achieve faster processing. The empirical results indicate significant improvements in image quality. The proposed approach speeds up deconvolution by about 10–50 times faster than that with the conventional Richardson–Lucy method.

  10. Scanning electron microscopy image representativeness: morphological data on nanoparticles.

    Science.gov (United States)

    Odziomek, Katarzyna; Ushizima, Daniela; Oberbek, Przemyslaw; Kurzydłowski, Krzysztof Jan; Puzyn, Tomasz; Haranczyk, Maciej

    2017-01-01

    A sample of a nanomaterial contains a distribution of nanoparticles of various shapes and/or sizes. A scanning electron microscopy image of such a sample often captures only a fragment of the morphological variety present in the sample. In order to quantitatively analyse the sample using scanning electron microscope digital images, and, in particular, to derive numerical representations of the sample morphology, image content has to be assessed. In this work, we present a framework for extracting morphological information contained in scanning electron microscopy images using computer vision algorithms, and for converting them into numerical particle descriptors. We explore the concept of image representativeness and provide a set of protocols for selecting optimal scanning electron microscopy images as well as determining the smallest representative image set for each of the morphological features. We demonstrate the practical aspects of our methodology by investigating tricalcium phosphate, Ca 3 (PO 4 ) 2 , and calcium hydroxyphosphate, Ca 5 (PO 4 ) 3 (OH), both naturally occurring minerals with a wide range of biomedical applications. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

  11. Platinum replica electron microscopy: Imaging the cytoskeleton globally and locally.

    Science.gov (United States)

    Svitkina, Tatyana M

    2017-05-01

    Structural studies reveal how smaller components of a system work together as a whole. However, combining high resolution of details with full coverage of the whole is challenging. In cell biology, light microscopy can image many cells in their entirety, but at a lower resolution, whereas electron microscopy affords very high resolution, but usually at the expense of the sample size and coverage. Structural analyses of the cytoskeleton are especially demanding, because cytoskeletal networks are unresolvable by light microscopy due to their density and intricacy, whereas their proper preservation is a challenge for electron microscopy. Platinum replica electron microscopy can uniquely bridge the gap between the "comfort zones" of light and electron microscopy by allowing high resolution imaging of the cytoskeleton throughout the entire cell and in many cells in the population. This review describes the principles and applications of platinum replica electron microscopy for studies of the cytoskeleton. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. 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...

  13. Image processing of small protein-crystals in electron microscopy

    International Nuclear Information System (INIS)

    Feinberg, D.A.

    1978-11-01

    This electron microscope study was undertaken to determine whether high resolution reconstructed images could be obtained from statistically noisy micrographs by the super-position of several small areas of images of well-ordered crystals of biological macromolecules. Methods of rotational and translational alignment which use Fourier space data were demonstrated to be superior to methods which use Real space image data. After alignment, the addition of the diffraction patterns of four small areas did not produce higher resolution because of unexpected image distortion effects. A method was developed to determine the location of the distortion origin and the coefficients of spiral distortion and pincushion/barrel distortion in order to make future correction of distortions in electron microscope images of large area crystals

  14. Image processing of small protein-crystals in electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Feinberg, D.A.

    1978-11-01

    This electron microscope study was undertaken to determine whether high resolution reconstructed images could be obtained from statistically noisy micrographs by the super-position of several small areas of images of well-ordered crystals of biological macromolecules. Methods of rotational and translational alignment which use Fourier space data were demonstrated to be superior to methods which use Real space image data. After alignment, the addition of the diffraction patterns of four small areas did not produce higher resolution because of unexpected image distortion effects. A method was developed to determine the location of the distortion origin and the coefficients of spiral distortion and pincushion/barrel distortion in order to make future correction of distortions in electron microscope images of large area crystals.

  15. Algorithms for contrast enhancement of electronic portal images

    International Nuclear Information System (INIS)

    Díez, S.; Sánchez, S.

    2015-01-01

    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. - Highlights: • Two Algorithms are implemented to improve the contrast of Electronic Portal Images. • The multi-leaf and conformed beam are automatically segmented into Portal Images. • Hidden anatomical and bony structures in portal images are revealed. • The task related to the patient setup verification is facilitated by the contrast enhancement then achieved.

  16. Future directions in electronic image handling.

    Science.gov (United States)

    Lemke, H U

    1993-08-01

    After a relatively slow start compared with the United States and Japan, several projects are now being established in Europe that are aimed at the development of prototype systems for medical image processing and management. Frequently, this includes aspects of multimedia communication, as well as legal, ethical, and economic issues. Consideration is also often given to systems security, reliability, and data protection. All these projects are based on the application of modern computer and communication technologies. The following interesting conclusions can be drawn from these preliminary activities: 1. PACS and IMAC systems should not be regarded as products or devices, but as a means to improve the infrastructure in a given medical care environment. Sometimes this activity is also referred to as knowledge business. Individual components of these systems, for example image acquisition devices, networks, storage facilities, and medical workstations, should be provided with standard interfaces allowing a modular build-up and an easy adaptation to the specific conditions of clinical departments. 2. Digital luminescence radiography will further establish itself as a method for image acquisition and increasingly will replace analog radiologic methods. Consequently, digital processing, archiving, and communication will be a necessity for optimal patient care. 3. New network technologies and magnetic-optical storage media offer the possibility of an improved cost-effectiveness for communication and storage. They should therefore be considered an important factor in future economic considerations regarding health care services. 4. The practice of modern medicine is based on team-work; good communication among the parties concerned is a critical factor.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Survey of standards for electronic image displays

    Science.gov (United States)

    Rowe, William A.

    1996-02-01

    Electronic visual displays have been evolving from the 1960's 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, hfs 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 the this standards activity are proposed.

  18. Image timing and detector performance of a matrix ion-chamber electronic portal imaging device

    International Nuclear Information System (INIS)

    Greer, P.

    1996-01-01

    The Oncology Centre of Auckland Hospital recently purchased a Varian PortalVision TM electronic portal imaging device (EPID). Image acquisition times, input-output characteristics and contrast-detail curves of this matrix liquid ion-chamber EPID have been measured to examine the variation in imaging performance with acquisition mode. The variation in detector performance with acquisition mode has been examined. The HV cycle time can be increased to improve image quality. Consideration should be given to the acquisition mode and HV cycle time used when imaging to ensure adequate imaging performance with reasonable imaging time. (author)

  19. Orientation-dependent imaging of electronically excited quantum dots

    Science.gov (United States)

    Nguyen, Duc; Goings, Joshua J.; Nguyen, Huy A.; Lyding, Joseph; Li, Xiaosong; Gruebele, Martin

    2018-02-01

    We previously demonstrated that we can image electronic excitations of quantum dots by single-molecule absorption scanning tunneling microscopy (SMA-STM). With this technique, a modulated laser beam periodically saturates an electronic transition of a single nanoparticle, and the resulting tunneling current modulation ΔI(x0, y0) maps out the SMA-STM image. In this paper, we first derive the basic theory to calculate ΔI(x0, y0) in the one-electron approximation. For near-resonant tunneling through an empty orbital "i" of the nanostructure, the SMA-STM signal is approximately proportional to the electron density |φi) (x0,y0)|imaged. We then show experimentally that we can nudge quantum dots on the surface and roll them, thus imaging excited state electronic structure of a single quantum dot at different orientations. We use density functional theory to model ODMs at various orientations, for qualitative comparison with the SMA-STM experiment. The model demonstrates that our experimentally observed signal monitors excited states, localized by defects near the surface of an individual quantum dot. The sub-nanometer super-resolution imaging technique demonstrated here could become useful for mapping out the three-dimensional structure of excited states localized by defects within nanomaterials.

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

    International Nuclear Information System (INIS)

    Wang, Y.; Hess, L.L.; Filoso, S.; Melack, J.M.

    1995-01-01

    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)

  1. Subparticle ultrafast spectrum imaging in 4D electron microscopy.

    Science.gov (United States)

    Yurtsever, Aycan; van der Veen, Renske M; Zewail, Ahmed H

    2012-01-06

    Single-particle imaging of structures has become a powerful methodology in nanoscience and molecular and cell biology. We report the development of subparticle imaging with space, time, and energy resolutions of nanometers, femtoseconds, and millielectron volts, respectively. By using scanning electron probes across optically excited nanoparticles and interfaces, we simultaneously constructed energy-time and space-time maps. Spectrum images were then obtained for the nanoscale dielectric fields, with the energy resolution set by the photon rather than the electron, as demonstrated here with two examples (silver nanoparticles and the metallic copper-vacuum interface). This development thus combines the high spatial resolution of electron microscopy with the high energy resolution of optical techniques and ultrafast temporal response, opening the door to various applications in elemental analysis as well as mapping of interfaces and plasmonics.

  2. 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.

  3. On the Stability of Reversely Formed Austenite and Related Mechanism of Transformation in an Fe-Ni-Mn Martensitic Steel Aided by Electron Backscattering Diffraction and Atom Probe Tomography

    Science.gov (United States)

    Koohdar, Hamidreza; Nili-Ahmadabadi, Mahmoud; Habibi-Parsa, Mohammad; Jafarian, Hamid Reza; Bhattacharjee, Tilak; Tsuji, Nobuhiro

    2017-11-01

    The stability of reversely formed austenite and related mechanism of transformation were investigated against temperature and time in an Fe-9.6Ni-7.1Mn (at. pct) martensitic steel during intercritical annealing at a dual-phase ( α + γ) region. Dilatometry, electron backscattering diffraction (EBSD), atom probe tomography (APT), and X-ray diffraction (XRD) were used to characterize the mechanism of reverse transformation. It was found that under intercritical annealing at 853 K (580 °C), when the heating rate is 20 K/s (20 °C/s), reverse transformation takes place through a mixed diffusion control mechanism, i.e., controlled by bulk diffusion and diffusion along the interface, where Ni controls the diffusion as its diffusivity is lower than that of Mn in the martensite and austenite. Increasing the intercritical annealing to 873 K (600 °C) at an identical heating rate of 20 K/s (20 °C/s) showed that reverse transformation occurs through a sequential combination of both martensitic and diffusional mechanisms. The transition temperature from diffusional to martensitic transformation was obtained close to 858 K (585 °C). Experimental results revealed that the austenite formed by the diffusional mechanism at 853 K (580 °C) mainly remains untransformed after cooling to ambient temperature due to the enrichment with Ni and Mn. It was also found that the stability of the reversely formed austenite by martensitic mechanism at 873 K (600 °C) is related to grain refinement.

  4. 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...

  5. Automatic solar image motion measurements. [electronic disk flux monitoring

    Science.gov (United States)

    Colgate, S. A.; Moore, E. P.

    1975-01-01

    The solar seeing image motion has been monitored electronically and absolutely with a 25 cm telescope at three sites along the ridge at the southern end of the Magdalena Mountains west of Socorro, New Mexico. The uncorrelated component of the variations of the optical flux from two points at opposite limbs of the solar disk was continually monitored in 3 frequencies centered at 0.3, 3 and 30 Hz. The frequency band of maximum signal centered at 3 Hz showed the average absolute value of image motion to be somewhat less than 2sec. The observer estimates of combined blurring and image motion were well correlated with electronically measured image motion, but the observer estimates gave a factor 2 larger value.

  6. 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.

  7. 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.

  8. 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

  9. Importance of daily electronic portal imaging in radiotherapy

    International Nuclear Information System (INIS)

    Bell, L. J.; Shakespeare, T. P.; Willis, A.

    2008-01-01

    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.

  10. Transmission scanning electron microscopy: Defect observations and image simulations.

    Science.gov (United States)

    Callahan, Patrick G; Stinville, Jean-Charles; Yao, Eric R; Echlin, McLean P; Titus, Michael S; De Graef, Marc; Gianola, Daniel S; Pollock, Tresa M

    2018-03-01

    The new capabilities of a FEG scanning electron microscope (SEM) equipped with a scanning transmission electron microscopy (STEM) detector for defect characterization have been studied in parallel with transmission electron microscopy (TEM) imaging. Stacking faults and dislocations have been characterized in strontium titanate, a polycrystalline nickel-base superalloy and a single crystal cobalt-base material. Imaging modes that are similar to conventional TEM (CTEM) bright field (BF) and dark field (DF) and STEM are explored, and some of the differences due to the different accelerating voltages highlighted. Defect images have been simulated for the transmission scanning electron microscopy (TSEM) configuration using a scattering matrix formulation, and diffraction contrast in the SEM is discussed in comparison to TEM. Interference effects associated with conventional TEM, such as thickness fringes and bending contours are significantly reduced in TSEM by using a convergent probe, similar to a STEM imaging modality, enabling individual defects to be imaged clearly even in high dislocation density regions. Beyond this, TSEM provides significant advantages for high throughput and dynamic in-situ characterization. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Watershed Merge Tree Classification for Electron Microscopy Image Segmentation

    OpenAIRE

    Liu, Ting; Jurrus, Elizabeth; Seyedhosseini, Mojtaba; Ellisman, Mark; Tasdizen, Tolga

    2012-01-01

    Automated segmentation of electron microscopy (EM) images is a challenging problem. In this paper, we present a novel method that utilizes a hierarchical structure and boundary classification for 2D neuron segmentation. With a membrane detection probability map, a watershed merge tree is built for the representation of hierarchical region merging from the watershed algorithm. A boundary classifier is learned with non-local image features to predict each potential merge in the tree, upon which...

  12. High-resolution imaging in the scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Pennycook, S.J.; Jesson, D.E.

    1992-03-01

    The high-resolution imaging of crystalline materials in the scanning transmission electron microscopy (STEM) is reviewed with particular emphasis on the conditions under which an incoherent image can be obtained. It is shown that a high-angle annular detector can be used to break the coherence of the imaging process, in the transverse plane through the geometry of the detector, or in three dimensions if multiphonon diffuse scattering is detected. In the latter case, each atom can be treated as a highly independent source of high-angle scattering. The most effective fast electron states are therefore tightly bound s-type Bloch states. Furthermore, they add constructively for each incident angle in the coherent STEM probe, so that s states are responsible for practically the entire image contrast. Dynamical effects are largely removed, and almost perfect incoherent imaging is achieved. s states are relatively insensitive to neighboring strings, so that incoherent imaging is maintained for superlattice and interfaces, and supercell calculations are unnecessary. With an optimum probe profile, the incoherent image represents a direct image of the crystal projection, with compositional sensitivity built in through the strong dependence of the scattering cross sections on atomic number Z

  13. Atomic imaging using secondary electrons in a scanning transmission electron microscope: experimental observations and possible mechanisms.

    Science.gov (United States)

    Inada, H; Su, D; Egerton, R F; Konno, M; Wu, L; Ciston, J; Wall, J; Zhu, Y

    2011-06-01

    We report detailed investigation of high-resolution imaging using secondary electrons (SE) with a sub-nanometer probe in an aberration-corrected transmission electron microscope, Hitachi HD2700C. This instrument also allows us to acquire the corresponding annular dark-field (ADF) images both simultaneously and separately. We demonstrate that atomic SE imaging is achievable for a wide range of elements, from uranium to carbon. Using the ADF images as a reference, we studied the SE image intensity and contrast as functions of applied bias, atomic number, crystal tilt, and thickness to shed light on the origin of the unexpected ultrahigh resolution in SE imaging. We have also demonstrated that the SE signal is sensitive to the terminating species at a crystal surface. A possible mechanism for atomic-scale SE imaging is proposed. The ability to image both the surface and bulk of a sample at atomic-scale is unprecedented, and can have important applications in the field of electron microscopy and materials characterization. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Imaging femtosecond laser-induced electronic excitation in glass

    International Nuclear Information System (INIS)

    Mao Xianglei; Mao, Samuel S.; Russo, Richard E.

    2003-01-01

    While substantial progress has been achieved in understanding laser ablation on the nanosecond and picosecond time scales, it remains a considerable challenge to elucidate the underlying mechanisms during femtosecond laser material interactions. We present experimental observations of electronic excitation inside a wide band gap glass during single femtosecond laser pulse (100 fs, 800 nm) irradiation. Using a femtosecond time-resolved imaging technique, we measured the evolution of a laser-induced electronic plasma inside the glass and calculated the electron number density to be on the order of 10 19 cm -3

  15. Hybrid fluorescence and electron cryo-microscopy for simultaneous electron and photon imaging.

    Science.gov (United States)

    Iijima, Hirofumi; Fukuda, Yoshiyuki; Arai, Yoshihiro; Terakawa, Susumu; Yamamoto, Naoki; Nagayama, Kuniaki

    2014-01-01

    Integration of fluorescence light and transmission electron microscopy into the same device would represent an important advance in correlative microscopy, which traditionally involves two separate microscopes for imaging. To achieve such integration, the primary technical challenge that must be solved regards how to arrange two objective lenses used for light and electron microscopy in such a manner that they can properly focus on a single specimen. To address this issue, both lateral displacement of the specimen between two lenses and specimen rotation have been proposed. Such movement of the specimen allows sequential collection of two kinds of microscopic images of a single target, but prevents simultaneous imaging. This shortcoming has been made up by using a simple optical device, a reflection mirror. Here, we present an approach toward the versatile integration of fluorescence and electron microscopy for simultaneous imaging. The potential of simultaneous hybrid microscopy was demonstrated by fluorescence and electron sequential imaging of a fluorescent protein expressed in cells and cathodoluminescence imaging of fluorescent beads. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Local dynamic range compensation for scanning electron microscope imaging system.

    Science.gov (United States)

    Sim, K S; Huang, Y H

    2015-01-01

    This is the extended project by introducing the modified dynamic range histogram modification (MDRHM) and is presented in this paper. This technique is used to enhance the scanning electron microscope (SEM) imaging system. By comparing with the conventional histogram modification compensators, this technique utilizes histogram profiling by extending the dynamic range of each tile of an image to the limit of 0-255 range while retains its histogram shape. The proposed technique yields better image compensation compared to conventional methods. © Wiley Periodicals, Inc.

  17. Imaging detectors and electronics - A view of the future

    International Nuclear Information System (INIS)

    Spieler, Helmuth

    2004-01-01

    Imaging sensors and readout electronics have made tremendous strides in the past two decades. The application of modern semiconductor fabrication techniques and the introduction of customized monolithic integrated circuits have made large scale imaging systems routine in high energy physics. This technology is now finding its way into other areas, such as space missions, synchrotron light sources, and medical imaging. I review current developments and discuss the promise and limits of new technologies. Several detector systems are described as examples of future trends. The discussion emphasizes semiconductor detector systems, but I also include recent developments for large-scale superconducting detector arrays

  18. Imaging detectors and electronics - A view of the future

    Energy Technology Data Exchange (ETDEWEB)

    Spieler, Helmuth

    2004-06-16

    Imaging sensors and readout electronics have made tremendous strides in the past two decades. The application of modern semiconductor fabrication techniques and the introduction of customized monolithic integrated circuits have made large scale imaging systems routine in high energy physics. This technology is now finding its way into other areas, such as space missions, synchrotron light sources, and medical imaging. I review current developments and discuss the promise and limits of new technologies. Several detector systems are described as examples of future trends. The discussion emphasizes semiconductor detector systems, but I also include recent developments for large-scale superconducting detector arrays.

  19. Secondary-electron-bremsstrahlung imaging for proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, Mitsutaka; Nagao, Yuto [Takasaki Advanced Radiation Research Institute, Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki-Machi, Takasaki, Gunma (Japan); Ando, Koki; Yamamoto, Seiichi [Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, 1-1-20 Daiko-Minami, Higashi-Ku, Nagoya, Aichi (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center, 1-1-1 Hirate-cho, Kita-Ku, Nagoya, Aichi (Japan); Kataoka, Jun [Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo (Japan); Kawachi, Naoki [Takasaki Advanced Radiation Research Institute, Quantum Beam Science Research Directorate, National Institutes for Quantum and Radiological Science and Technology, 1233 Watanuki-Machi, Takasaki, Gunma (Japan)

    2016-10-11

    A feasibility study on an imaging technique of a therapeutic proton-beam trajectory using a gamma camera by measuring secondary electron bremsstrahlung (SEB) was performed by means of Monte Carlo simulations and a beam-irradiation experiment. From the simulation and experimental results, it was found that a significant amount of SEB yield exists between the beam-injection surface and the range position along the beam axis and the beam trajectory is clearly imaged by the SEB yield. It is concluded that the SEB imaging is a promising technique for monitoring of therapeutic proton-beam trajectories.

  20. 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...

  1. Electronic roentgenographic images in presurgical X-ray diagnostics

    International Nuclear Information System (INIS)

    Haendle, J.; Hohmann, D.; Maass, W.; Siemens A.G., Erlangen

    1981-01-01

    An essential part of radiation exposure in surgery is due to devices and results from the required radiation time interval for continuous X-ray play-back up to the point at which all diagnostically relevant information can be retrieved from the screening image. With single-image storage and short exposure times as well as instant image play-back, this superfluous i.e. redundant radiation can be avoided. The electronic X-ray image is realized by means of a laboratory prototype and evaluated in hospitals. There is a report on clinical results and new technical developments. Remarkable are: the high radiation reduction that could be obtained, the problem - free instant image technique, and especially the advantages of automated exposure in direct film settings. The positive results yield the basis for the product development. (orig./MG) [de

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

    Science.gov (United States)

    2012-06-29

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-850] Certain Electronic Imaging Devices; Institution of Investigation AGENCY: U.S. International Trade Commission. ACTION: Notice. SUMMARY: Notice is hereby given that a complaint was filed with the U.S. International Trade Commission on May 23, 2012...

  3. Structure Identification in High-Resolution Transmission Electron Microscopic Images

    DEFF Research Database (Denmark)

    Vestergaard, Jacob Schack; Kling, Jens; Dahl, Anders Bjorholm

    2014-01-01

    A connection between microscopic structure and macroscopic properties is expected for almost all material systems. High-resolution transmission electron microscopy is a technique offering insight into the atomic structure, but the analysis of large image series can be time consuming. The present ...

  4. Removal of vesicle structures from transmission electron microscope images

    DEFF Research Database (Denmark)

    Jensen, Katrine Hommelhoff; Sigworth, Fred J.; Brandt, Sami Sebastian

    2016-01-01

    In this paper, we address the problem of imaging membrane proteins for single-particle cryo-electron microscopy reconstruction of the isolated protein structure. More precisely, we propose a method for learning and removing the interfering vesicle signals from the micrograph, prior to reconstruct...

  5. Imaging of ionizing radiations from electronic avalanches, limited, in gases

    International Nuclear Information System (INIS)

    Charpak, G.

    1995-01-01

    This work deals with the imaging of ionizing radiations from electronic avalanches in gases. Some applications realized with the help of physical instruments like : fog chambers, Geiger-Mueller counters, proportional counters, scintillation counters, semiconductor detectors, nuclear emulsions, bubble chambers, drift chambers, wire spark chambers and calorimeters are described and their performances compared. (O.L.). 5 refs., 10 figs

  6. Multibeam sonar backscatter data processing

    Science.gov (United States)

    Schimel, Alexandre C. G.; Beaudoin, Jonathan; Parnum, Iain M.; Le Bas, Tim; Schmidt, Val; Keith, Gordon; Ierodiaconou, Daniel

    2018-01-01

    Multibeam sonar systems now routinely record seafloor backscatter data, which are processed into backscatter mosaics and angular responses, both of which can assist in identifying seafloor types and morphology. Those data products are obtained from the multibeam sonar raw data files through a sequence of data processing stages that follows a basic plan, but the implementation of which varies greatly between sonar systems and software. In this article, we provide a comprehensive review of this backscatter data processing chain, with a focus on the variability in the possible implementation of each processing stage. Our objective for undertaking this task is twofold: (1) to provide an overview of backscatter data processing for the consideration of the general user and (2) to provide suggestions to multibeam sonar manufacturers, software providers and the operators of these systems and software for eventually reducing the lack of control, uncertainty and variability associated with current data processing implementations and the resulting backscatter data products. One such suggestion is the adoption of a nomenclature for increasingly refined levels of processing, akin to the nomenclature adopted for satellite remote-sensing data deliverables.

  7. Effective cellulose nanocrystal imaging using transmission electron microscopy.

    Science.gov (United States)

    Stinson-Bagby, Kelly L; Roberts, Rose; Foster, E Johan

    2018-04-15

    Characterization of cellulose nanocrystals (CNCs) is often complex and tedious. With their increased use for biological materials, polymer reinforcing agents, and other applications, better characterization methods of CNCs are needed to ensure product quality. However, because of their small size, hydrogen bonding, and low electron density, individual CNCs are difficult to image with high resolution and magnification using electron microscopy. Methods to help counter these challenges include staining for increased contrast and techniques to increase dispersion. This work tested several stains, dispersing agents, and sample supports to find a consistent method of individualizing CNCs and providing good contrast for imaging in transmission electron microscopy (TEM). The most consistent method found uses a low concentration of CNCs, bovine serum albumin as a dispersing agent, and Nanovan ® as the contrasting stain on a silicon monoxide-coated Formvar TEM grid. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. 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.

  9. An electron density measurement using an analyzer based imaging system

    International Nuclear Information System (INIS)

    Bewer, Brian

    2011-01-01

    Using a monochromatic X-ray beam from a synchrotron source the electron density of a homogeneous target was determined by measuring the refraction that occurs at the air-target interface for a known angle of incidence. The angle of deviation that these X-rays undergo at the transition between materials is micro-radian to submicro-radian in scale. Existing analyzer based imaging systems are designed to measure submicro-radian angle changes and commonly use monochromatic hard X-ray beams generated from synchrotron sources. A preliminary experiment using the analyzer based imaging apparatus at the Canadian Light Source Biomedical Imaging and Therapy beamline and a half cylinder shaped plastic target will be presented. By measuring the angle of deviation of the photon beam at several discrete angular positions of the target the electron density of the target material was determined.

  10. 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

  11. Electron optical analysis of a retarding Wien filter for electron spectroscopic imaging

    Science.gov (United States)

    Tsuno, K.

    1993-03-01

    A new Wien filter has been designed for electron spectroscopic imaging. The shape of the electrodes and the magnetic pole pieces of the filter has fourfold symmetry and therefore the Wien condition giving a straight optical axis is satisfied even in the fringing field region. The second-order aberration coefficients of the filter are formulated in a simple form. The filter is applied to a spectroscopic low-energy reflection electron microscope in a retarding condition. The optics of the image-forming lens system is analyzed using the transfer matrix method. The achromatic focus is achieved when the distances of the objective plane and the imaginary image plane to the filter are equal. A condition for obtaining the image free from second-order aberrations is found. The total magnification of the instrument is 3000-14000 times; energy resolution of 2 eV is attained for an initial beam divergence angle of 10 mrad.

  12. Genesis of diamond inclusions: An integrated cathodoluminescence (CL) and Electron backscatter diffraction (EBSD) study on eclogitic and peridotitic inclusions and their diamond host.

    Science.gov (United States)

    van den Heuvel, Quint; Matveev, Sergei; Drury, Martyn; Gress, Michael; Chinn, Ingrid; Davies, Gareth

    2017-04-01

    Diamond inclusions are potentially fundamental to understanding the formation conditions of diamond and the volatile cycles in the deep mantle. In order to fully understand the implications of the compositional information recorded by inclusions it is vital to know whether the inclusions are proto-, syn-, or epigenetic and the extent to which they have equilibrated with diamond forming fluids. In previous studies, the widespread assumption was made that the majority of diamond inclusions are syngenetic, based upon observation of cubo-octahedral morphology imposed on the inclusions. Recent work has reported the crystallographic relationship between inclusions and the host diamond to be highly complex and the lack of crystallographic relationships between inclusions and diamonds has led some to question the significance of imposed cubo-octahedral morphology. This study presents an integrated EBSD and CL study of 9 diamonds containing 20 pyropes, 2 diopsides, 1 forsterite and 1 rutile from the Jwaneng and Letlhakane kimberlite clusters, Botswana. A new method was developed to analyze the crystallographic orientation of the host diamond and the inclusions with EBSD. Diamonds plates were sequentially polished to expose inclusions at different levels in the diamond. CL imaging at different depths was performed in order to produce a 3D view of diamond growth zones around the inclusions. Standard diamond polishing techniques proved too aggressive for silicate inclusions as they were damaged to such a degree that EBSD measurements on the inclusions were impossible. The inclusions were milled with a Ga+ focused ion beam (FIB) at a 12° angle to clean the surface for EBSD measurements. Of the 24 inclusions, 9 have an imposed cubo-octahedral morphology. Of these inclusions, 6 have faces orientated parallel to diamond growth zones and/or appear to have nucleated on a diamond growth surface, implying syngenesis. In contrast, other diamonds record resorption events such that

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

    International Nuclear Information System (INIS)

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

    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 k-bar θ is calculated to be about 1.58 cm −1 , or k-bar θρ s thickapprox 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. (fluids, plasmas and electric discharges)

  14. Electron microscopy analysis of structural changes within white etching areas

    DEFF Research Database (Denmark)

    Diederichs, Annika Martina; Schwedt, A.; Mayer, J.

    2016-01-01

    In the present work, crack networks with white etching areas (WEAs) in cross-sections of bearings were investigated by a complementary use of SEM and TEM with the focus on the use of orientation contrast imaging and electron backscatter diffraction (EBSD). Orientation contrast imaging was used...

  15. Volume scanning electron microscopy for imaging biological ultrastructure.

    Science.gov (United States)

    Titze, Benjamin; Genoud, Christel

    2016-11-01

    Electron microscopy (EM) has been a key imaging method to investigate biological ultrastructure for over six decades. In recent years, novel volume EM techniques have significantly advanced nanometre-scale imaging of cells and tissues in three dimensions. Previously, this had depended on the slow and error-prone manual tasks of cutting and handling large numbers of sections, and imaging them one-by-one with transmission EM. Now, automated volume imaging methods mostly based on scanning EM (SEM) allow faster and more reliable acquisition of serial images through tissue volumes and achieve higher z-resolution. Various software tools have been developed to manipulate the acquired image stacks and facilitate quantitative analysis. Here, we introduce three volume SEM methods: serial block-face electron microscopy (SBEM), focused ion beam SEM (FIB-SEM) and automated tape-collecting ultramicrotome SEM (ATUM-SEM). We discuss and compare their capabilities, provide an overview of the full volume SEM workflow for obtaining 3D datasets and showcase different applications for biological research. © 2016 Société Française des Microscopies and Société de Biologie Cellulaire de France. Published by John Wiley & Sons Ltd.

  16. Enhanced contrast separation in scanning electron microscopes via a suspended-thin sample approach.

    Science.gov (United States)

    Ji, Yuan; Wang, Li; Guo, Zhenxi; Wei, Bin; Zhao, Jie; Wang, Xiaodong; Zhang, Yinqi; Sui, Manling; Han, Xiaodong

    2014-11-01

    A suspended-thin-sample (STS) approach for signal selection and contrast separation is developed in scanning electron microscopes with commonly used primary beam energies and traditional detectors. Topography contrast, electron channeling contrast and composition contrast are separated and largely enhanced from suspended thin samples of several hundred nanometers in thickness, which is less than the escape depth of backscattered electrons. This imaging technique enables to detect relatively pure secondary electron and elastic backscattered electron singles, whereas suppress multiple inelastic scattering effects. The provided contrast features are different from those of bulk samples, which are largely mixed with inelastic scattering effects. The STS imaging concept and method could be expected to have more applications in distinguishing materials of nanostructures, multilayers, compounds and composites, as well as in SEM-based electron backscatter diffraction, cathodoluminesence, and x-ray microanalysis. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. From the physics of secondary electron emission to image contrasts in scanning electron microscopy.

    Science.gov (United States)

    Cazaux, Jacques

    2012-01-01

    Image formation in scanning electron microscopy (SEM) is a combination of physical processes, electron emissions from the sample, and of a technical process related to the detection of a fraction of these electrons. For the present survey of image contrasts in SEM, simplified considerations in the physics of the secondary electron emission yield, δ, are combined with the effects of a partial collection of the emitted secondary electrons. Although some consideration is initially given to the architecture of modern SEM, the main attention is devoted to the material contrasts with the respective roles of the sub-surface and surface compositions of the sample, as well as with the roles of the field effects in the vacuum gap. The recent trends of energy filtering in normal SEM and the reduction of the incident energy to a few electron volts in very low-energy electron microscopy are also considered. For an understanding by the SEM community, the mathematical expressions are explained with simple physical arguments.

  18. Imaging systems in the Delft Multi-Beam Scanning Electron Microscope 1

    NARCIS (Netherlands)

    Ren, Y.

    2017-01-01

    The goal of this Ph.D. research is to develop imaging systems for the multiple beam scanning electron microscope (MBSEM) built in Delft University of Technology. This thesis includes two imaging systems, transmission electron (TE) imaging system, and secondary electron (SE) imaging system. The major

  19. Prospective clinical evaluation of an electronic portal imaging device

    International Nuclear Information System (INIS)

    Michalski, Jeff M.; Graham, Mary V.; Bosch, Walter R.; Wong, John; Gerber, Russell L.; Cheng, Abel; Tinger, Alfred; Valicenti, Richard K.

    1996-01-01

    Purpose: To determine whether the clinical implementation of an electronic portal imaging device can improve the precision of daily external beam radiotherapy. Methods and Materials: In 1991, an electronic portal imaging device was installed on a dual energy linear accelerator in our clinic. After training the radiotherapy technologists in the acquisition and evaluation of portal images, we performed a randomized study to determine whether online observation, interruption, and intervention would result in more precise daily setup. The patients were randomized to one of two groups: those whose treatments were actively monitored by the radiotherapy technologists and those that were imaged but not monitored. The treating technologists were instructed to correct the following treatment errors: (a) field placement error (FPE) > 1 cm; (b) incorrect block; (c) incorrect collimator setting; (d) absent customized block. Time of treatment delivery was recorded by our patient tracking and billing computers and compared to a matched set of patients not participating in the study. After the patients radiation therapy course was completed, an offline analysis of the patient setup error was planned. Results: Thirty-two patients were treated to 34 anatomical sites in this study. In 893 treatment sessions, 1,873 fields were treated (1,089 fields monitored and 794 fields unmonitored). Ninety percent of the treated fields had at least one image stored for offline analysis. Eighty-seven percent of these images were analyzed offline. Of the 1,011 fields imaged in the monitored arm, only 14 (1.4%) had an intervention recorded by the technologist. Despite infrequent online intervention, offline analysis demonstrated that the incidence of FPE > 10 mm in the monitored and unmonitored groups was 56 out of 881 (6.1%) and 95 out of 595 (11.2%), respectively; p 10 mm was confined to the pelvic fields. The time to treat patients in this study was 10.78 min (monitored) and 10.10 min (unmonitored

  20. 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....

  1. Online measurement of electron beam parameters by image processing

    International Nuclear Information System (INIS)

    Tyagi, Y.; Puntambekar, T.A.

    2010-01-01

    The basic image acquisition software which was developed earlier has been recently upgraded to support online measurement of beam centroid, beam height and beam width from the diagnostic devices namely fluorescent screen beam profile monitors and beam slit monitor installed in Transport Line -1(TL-1) at Indus Accelerator Complex at RRCAT, Indore. The online measurement of these electron beam parameters has helped the Indus operation team to take necessary corrective action if required before injection of the electron beam into booster synchrotron. This paper presents the methodology adopted for online measurement of above parameters in the software. (author)

  2. Pico-femtosecond image-tube photography in quantum electronics

    International Nuclear Information System (INIS)

    Schelev, M Ya

    2001-01-01

    The possibility of experimental achievement of the time resolution of image-converter tubes (ICTs) corresponding to the theoretical limit of 10 fs is considered as applied to quantum electronics problems. A new generation of ICTs with a temporal resolution of 200 - 500 fs has been developed for recording femtosecond laser radiation. The entirely new devices based on time-analysing ICTs such as femtosecond photoelectronic diffractometers, have been created for studying the dynamics of phase transitions in substances using diffrac-tion of electrons with energies ranging from 20 to 40 keV. (femtosecond technologies)

  3. Simultaneous Scanning Electron Microscope Imaging of Topographical and Chemical Contrast Using In-Lens, In-Column, and Everhart-Thornley Detector Systems.

    Science.gov (United States)

    Zhang, Xinming; Cen, Xi; Ravichandran, Rijuta; Hughes, Lauren A; van Benthem, Klaus

    2016-06-01

    The scanning electron microscope provides a platform for subnanometer resolution characterization of material morphology with excellent topographic and chemical contrast dependent on the used detectors. For imaging applications, the predominantly utilized signals are secondary electrons (SEs) and backscattered electrons (BSEs) that are emitted from the sample surface. Recent advances in detector technology beyond the traditional Everhart-Thornley geometry have enabled the simultaneous acquisition and discrimination of SE and BSE signals. This study demonstrates the imaging capabilities of a recently introduced new detector system that consists of the combination of two in-lens (I-L) detectors and one in-column (I-C) detector. Coupled with biasing the sample stage to reduce electron-specimen interaction volumes, this trinity of detector geometry allows simultaneous acquisition of signals to distinguish chemical contrast from topographical changes of the sample, including the identification of surface contamination. The I-C detector provides 4× improved topography, whereas the I-L detector closest to the sample offers excellent simultaneous chemical contrast imaging while not limiting the minimization of working distance to obtain optimal lateral resolution. Imaging capabilities and contrast mechanisms for all three detectors are discussed quantitatively in direct comparison to each other and the conventional Everhart-Thornley detector.

  4. Scanning electron image analysis to monitor of implant degradation and host healing following implantation of a drug-eluting bone graft void filler - biomed 2013.

    Science.gov (United States)

    Davidoff, Sherry N; Lawson, Scott T; Grainger, David W; Brooks, Amanda E

    2013-01-01

    Osteomyelitis is most commonly caused by Staphylococcus aureus and often sourced during orthopedic surgical intervention. Successful treatment or prevention of this bone penetrating infection requires antibiotics be delivered in excess of the minimal inhibitory concentration to prohibit the growth of the causative organism for sufficient duration. Unfortunately, current standard-of-care antibiotic therapies, administered via intravenous or oral delivery, suffer not only from systemic toxicity and low patient compliance but also provide insufficient local concentrations for therapy. To overcome these clinical inadequacies, a synthetic bone graft material was coated with an antibiotic (tobramycin)-releasing polymer (polycaprolactone) matrix to create a polymer-controlled antibiotic- releasing combination therapy for use as a bone void filler in orthopedic surgeries. Even though this local delivery strategy allows antibiotic delivery over a clinically relevant time frame to prevent infection, complete healing requires the host bone to infiltrate and reabsorb the bone void filler, ultimately replacing the defect with healthy tissue. Unfortunately, the same polymer matrix that allows for controlled local antibiotic delivery may also discourage host bone healing. Efficient orthopedic healing requires the rate of polymer degradation to match the rate of host-bone infiltration. Current imaging techniques, such as histological staining and x-ray imaging, are insufficient to simultaneously assess polymer degradation and host bone integration. Alternative techniques relying on backscatter electron detection during scanning electron microscopy (SEM) imaging may allow a visual differentiation between host bone, synthetic bone, and polymer. Analysis of backscattered SEM images was automated using a custom MATLAB program to determine the ratio of bone to polymer based upon the contrast between the bone (white) and polymer (dark grey). By collecting images of the implant over time

  5. Adaptive noise Wiener filter for scanning electron microscope imaging system.

    Science.gov (United States)

    Sim, K S; Teh, V; Nia, M E

    2016-01-01

    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. © Wiley Periodicals, Inc.

  6. 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.

  7. 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 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......Rad. The precision limits of the measurement of dose were found to be ±4%. The procedure was simple and the holographic equipment stable and compact, thus allowing experimentation under routine laboratory conditions and limited space....

  8. Electronic photography: a new age of medical imaging?

    Science.gov (United States)

    Tübergen, D; Manegold, B C

    1993-07-01

    This is a critical overview of present conceptions of the introduction of electronic photography in medicine. It is not a complete list of products, rather it is a description of how the requirements of the physician have influenced medical illustration in the past and will continue to do so in the future. Video systems are widely used in medicine. Besides the learning and teaching of effects of television, minimal invasive surgery (MIS) has become reality through endoscopy, rapidly accepted worldwide. Documentation of endoscopic procedures and their effects is becoming routine. Therefore, the conversion of complex optical information into binary units is a logical development to save space for storage. The reproduction, storage and transfer of detailed images is already realized by digital camera systems, photo CD, scanners and picture archiving and communicating system (PACS). Now electronic imaging in medicine has to be regarded as a matter of routine. The real impact of accelerated editing will be shown in the future.

  9. 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...

  10. Imaging local electronic corrugations and doped regions in graphene.

    Science.gov (United States)

    Schultz, Brian J; Patridge, Christopher J; Lee, Vincent; Jaye, Cherno; Lysaght, Patrick S; Smith, Casey; Barnett, Joel; Fischer, Daniel A; Prendergast, David; Banerjee, Sarbajit

    2011-06-28

    Electronic structure heterogeneities are ubiquitous in two-dimensional graphene and profoundly impact the transport properties of this material. Here we show the mapping of discrete electronic domains within a single graphene sheet using scanning transmission X-ray microscopy in conjunction with ab initio density functional theory calculations. Scanning transmission X-ray microscopy imaging provides a wealth of detail regarding the extent to which the unoccupied levels of graphene are modified by corrugation, doping and adventitious impurities, as a result of synthesis and processing. Local electronic corrugations, visualized as distortions of the π*cloud, have been imaged alongside inhomogeneously doped regions characterized by distinctive spectral signatures of altered unoccupied density of states. The combination of density functional theory calculations, scanning transmission X-ray microscopy imaging, and in situ near-edge X-ray absorption fine structure spectroscopy experiments also provide resolution of a longstanding debate in the literature regarding the spectral assignments of pre-edge and interlayer states.

  11. 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

  12. Advanced electron crystallography through model-based imaging

    Directory of Open Access Journals (Sweden)

    Sandra Van Aert

    2016-01-01

    Full Text Available 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.

  13. Low energy electron point source microscopy: beyond imaging.

    Science.gov (United States)

    Beyer, André; Gölzhäuser, Armin

    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.

  14. Imaging and electron energy-loss spectroscopy using single nanosecond electron pulses.

    Science.gov (United States)

    Picher, Matthieu; Bücker, Kerstin; LaGrange, Thomas; Banhart, Florian

    2018-03-13

    We implement a parametric study with single electron pulses having a 7 ns duration to find the optimal conditions for imaging, diffraction, and electron energy-loss spectroscopy (EELS) in the single-shot approach. Photoelectron pulses are generated by illuminating a flat tantalum cathode with 213 nm nanosecond laser pulses in a 200 kV transmission electron microscope (TEM) with thermionic gun and Wehnelt electrode. For the first time, an EEL spectrometer is used to measure the energy distribution of single nanosecond electron pulses which is crucial for understanding the ideal imaging conditions of the single-shot approach. By varying the laser power, the Wehnelt bias, and the condenser lens settings, the optimum TEM operation conditions for the single-shot approach are revealed. Due to space charge and the Boersch effect, the energy width of the pulses under maximized emission conditions is far too high for imaging or spectroscopy. However, by using the Wehnelt electrode as an energy filter, the energy width of the pulses can be reduced to 2 eV, though at the expense of intensity. The first EEL spectra taken with nanosecond electron pulses are shown in this study. With 7 ns pulses, an image resolution of 25 nm is attained. It is shown how the spherical and chromatic aberrations of the objective lens as well as shot noise limit the resolution. We summarize by giving perspectives for improving the single-shot time-resolved approach by using aberration correction. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Fast imaging with inelastically scattered electrons by off-axis chromatic confocal electron microscopy.

    Science.gov (United States)

    Zheng, Changlin; Zhu, Ye; Lazar, Sorin; Etheridge, Joanne

    2014-04-25

    We introduce off-axis chromatic scanning confocal electron microscopy, a technique for fast mapping of inelastically scattered electrons in a scanning transmission electron microscope without a spectrometer. The off-axis confocal mode enables the inelastically scattered electrons to be chromatically dispersed both parallel and perpendicular to the optic axis. This enables electrons with different energy losses to be separated and detected in the image plane, enabling efficient energy filtering in a confocal mode with an integrating detector. We describe the experimental configuration and demonstrate the method with nanoscale core-loss chemical mapping of silver (M4,5) in an aluminium-silver alloy and atomic scale imaging of the low intensity core-loss La (M4,5@840  eV) signal in LaB6. Scan rates up to 2 orders of magnitude faster than conventional methods were used, enabling a corresponding reduction in radiation dose and increase in the field of view. If coupled with the enhanced depth and lateral resolution of the incoherent confocal configuration, this offers an approach for nanoscale three-dimensional chemical mapping.

  16. 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...

  17. 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...

  18. Electron imaging with Medipix2 hybrid pixel detector

    CERN Document Server

    McMullan, G; Chen, S; Henderson, R; Llopart, X; Summerfield, C; Tlustos, L; Faruqi, A R

    2007-01-01

    The electron imaging performance of Medipix2 is described. Medipix2 is a hybrid pixel detector composed of two layers. It has a sensor layer and a layer of readout electronics, in which each 55 μm×55 μm pixel has upper and lower energy discrimination and MHz rate counting. The sensor layer consists of a 300 μm slab of pixellated monolithic silicon and this is bonded to the readout chip. Experimental measurement of the detective quantum efficiency, DQE(0) at 120 keV shows that it can reach 85% independent of electron exposure, since the detector has zero noise, and the DQE(Nyquist) can reach 35% of that expected for a perfect detector (4/π2). Experimental measurement of the modulation transfer function (MTF) at Nyquist resolution for 120 keV electrons using a 60 keV lower energy threshold, yields a value that is 50% of that expected for a perfect detector (2/π). Finally, Monte Carlo simulations of electron tracks and energy deposited in adjacent pixels have been performed and used to calculate expected v...

  19. High-resolution, high-throughput imaging with a multibeam scanning electron microscope.

    Science.gov (United States)

    Eberle, A L; Mikula, S; Schalek, R; Lichtman, J; Knothe Tate, M L; Zeidler, D

    2015-08-01

    Electron-electron interactions and detector bandwidth limit the maximal imaging speed of single-beam scanning electron microscopes. We use multiple electron beams in a single column and detect secondary electrons in parallel to increase the imaging speed by close to two orders of magnitude and demonstrate imaging for a variety of samples ranging from biological brain tissue to semiconductor wafers. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  20. Nanodiamond Landmarks for Subcellular Multimodal Optical and Electron Imaging

    Science.gov (United States)

    Zurbuchen, Mark A.; Lake, Michael P.; Kohan, Sirus A.; Leung, Belinda; Bouchard, Louis-S.

    2013-01-01

    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 sub-cellular 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 nanodiamonds, such as biocompatibility, sensitive magnetometry, and gene and drug delivery. PMID:24036840

  1. 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.

  2. Diverse Protocols for Correlative Super-Resolution Fluorescence Imaging and Electron Microscopy of Cells and Tissue

    Science.gov (United States)

    2016-05-25

    super - resolution fluorescence imaging and electron microscopy of cells and tissue Benjamin G. Kopek1, Maria G...have recently developed related approaches for super - resolution imaging within endogenous cellular environments using correlative light and electron...low as ~10 nm under ideal conditions), collectively dubbed “ super - resolution imaging ”5-10. A major super - resolution imaging modality is

  3. Imaging and Quantification of Extracellular Vesicles by Transmission Electron Microscopy.

    Science.gov (United States)

    Linares, Romain; Tan, Sisareuth; Gounou, Céline; Brisson, Alain R

    2017-01-01

    Extracellular vesicles (EVs) are cell-derived vesicles that are present in blood and other body fluids. EVs raise major interest for their diverse physiopathological roles and their potential biomedical applications. However, the characterization and quantification of EVs constitute major challenges, mainly due to their small size and the lack of methods adapted for their study. Electron microscopy has made significant contributions to the EV field since their initial discovery. Here, we describe the use of two transmission electron microscopy (TEM) techniques for imaging and quantifying EVs. Cryo-TEM combined with receptor-specific gold labeling is applied to reveal the morphology, size, and phenotype of EVs, while their enumeration is achieved after high-speed sedimentation on EM grids.

  4. 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...

  5. P12 V ORBITING RADAR DERIVED BACKSCATTER CROSS SECTION V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of a VICAR2 format image of Venus large-angle radar backscatter cross section, from the side-looking mode of the Pioneer Venus radar mapper...

  6. 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...

  7. 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...

  8. Backscattered Helium Spectroscopy in the Helium Ion Microscope: Principles, Resolution and Applications

    NARCIS (Netherlands)

    van Gastel, Raoul; Hlawacek, G.; Dutta, S.; Poelsema, Bene

    2015-01-01

    We demonstrate the possibilities and limitations for microstructure characterization using backscattered particles from a sharply focused helium ion beam. The interaction of helium ions with matter enables the imaging, spectroscopic characterization, as well as the nanometer scale modification of

  9. 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.

  10. Watershed Merge Tree Classification for Electron Microscopy Image Segmentation.

    Science.gov (United States)

    Liu, Ting; Jurrus, Elizabeth; Seyedhosseini, Mojtaba; Ellisman, Mark; Tasdizen, Tolga

    2012-11-01

    Automated segmentation of electron microscopy (EM) images is a challenging problem. In this paper, we present a novel method that utilizes a hierarchical structure and boundary classification for 2D neuron segmentation. With a membrane detection probability map, a watershed merge tree is built for the representation of hierarchical region merging from the watershed algorithm. A boundary classifier is learned with non-local image features to predict each potential merge in the tree, upon which merge decisions are made with consistency constraints to acquire the final segmentation. Independent of classifiers and decision strategies, our approach proposes a general framework for efficient hierarchical segmentation with statistical learning. We demonstrate that our method leads to a substantial improvement in segmentation accuracy.

  11. Initial experience with a electronic CT image transfer system.

    Science.gov (United States)

    Bell, K. E.; Loughrey, C.; Morrison, C. M.

    1994-01-01

    An electronic image transfer system for computed tomographic images links the CT scanner in Altnagelvin Hospital, Londonderry with the regional neuroradiology department in the Royal Victoria Hospital, Belfast. In the first 13 months of operation, scans of 100 patients were transferred; 49 scans were taken in acute neurosurgical emergencies, and 51 were non-acute sent for a specialist neuroradiological opinion. Potentially hazardous inter-hospital transfer was avoided in 21 cases of acute neurosurgical emergency, and more efficient and appropriate referral was achieved in the cases whose scans had been sent for sent for radiological second opinion. We believe that the system has substantially improved the diagnosis and management of patients with neurosurgical problems in both hospitals. PMID:8658991

  12. 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.

  13. Diffuse optical microscopy for quantification of depth-dependent epithelial backscattering in the cervix

    Science.gov (United States)

    Bodenschatz, Nico; Lam, Sylvia; Carraro, Anita; Korbelik, Jagoda; Miller, Dianne M.; McAlpine, Jessica N.; Lee, Marette; Kienle, Alwin; MacAulay, Calum

    2016-06-01

    A fiber optic imaging approach is presented using structured illumination for quantification of almost pure epithelial backscattering. We employ multiple spatially modulated projection patterns and camera-based reflectance capture to image depth-dependent epithelial scattering. The potential diagnostic value of our approach is investigated on cervical ex vivo tissue specimens. Our study indicates a strong backscattering increase in the upper part of the cervical epithelium caused by dysplastic microstructural changes. Quantization of relative depth-dependent backscattering is confirmed as a potentially useful diagnostic feature for detection of precancerous lesions in cervical squamous epithelium.

  14. Coherent backscattering in the soft x-ray region

    International Nuclear Information System (INIS)

    Matone, G.; Luccio, A.

    1986-06-01

    It is shown that coherent polarized soft x-rays can be produced by a combination of two techniques - stimulated amplification of laser light in a magnetic undulator, and Compton scattering of laser photons on an electron beam. In the combined technique, laser radiation is Compton scattered from a relativistic electron beam, whose current or charge density is periodically modulated. An electron beam and a laser beam propagate through an undulator along the same line. Inside the undulator, the laser electromagnetic waste produces a modulation of the electron energy. After some drift space, the modulation of the electron energy transforms into a modulation of the beam longitudinal charge density. The laser photons are reflected by a concave mirror against the electrons and are backscattered. In the process, their energy is greatly increased. If the electron and laser photon energy are matched properly, the modulated electron beam may act as a moving diffraction grating, and the backscattered x-rays show a high degree of coherence. The mechanism of modulation is described. The effects of electron beam energy spread, finite electron beam emittance, and undulator imperfections are discussed. The theory of scattering of a light wave by a bunched electron beam and the properties of the scattered radiation are examined

  15. Residual Deconvolutional Networks for Brain Electron Microscopy Image Segmentation.

    Science.gov (United States)

    Fakhry, Ahmed; Zeng, Tao; Ji, Shuiwang

    2017-02-01

    Accurate reconstruction of anatomical connections between neurons in the brain using electron microscopy (EM) images is considered to be the gold standard for circuit mapping. A key step in obtaining the reconstruction is the ability to automatically segment neurons with a precision close to human-level performance. Despite the recent technical advances in EM image segmentation, most of them rely on hand-crafted features to some extent that are specific to the data, limiting their ability to generalize. Here, we propose a simple yet powerful technique for EM image segmentation that is trained end-to-end and does not rely on prior knowledge of the data. Our proposed residual deconvolutional network consists of two information pathways that capture full-resolution features and contextual information, respectively. We showed that the proposed model is very effective in achieving the conflicting goals in dense output prediction; namely preserving full-resolution predictions and including sufficient contextual information. We applied our method to the ongoing open challenge of 3D neurite segmentation in EM images. Our method achieved one of the top results on this open challenge. We demonstrated the generality of our technique by evaluating it on the 2D neurite segmentation challenge dataset where consistently high performance was obtained. We thus expect our method to generalize well to other dense output prediction problems.

  16. An electron beam imaging system for quality assurance in IORT

    Science.gov (United States)

    Casali, F.; Rossi, M.; Morigi, M. P.; Brancaccio, R.; Paltrinieri, E.; Bettuzzi, M.; Romani, D.; Ciocca, M.; Tosi, G.; Ronsivalle, C.; Vignati, M.

    2004-01-01

    Intraoperative radiation therapy is a special radiotherapy technique, which enables a high dose of radiation to be given in a single fraction during oncological surgery. The major stumbling block to the large-scale application of the technique is the transfer of the patient, with an open wound, from the operating room to the radiation therapy bunker, with the consequent organisational problems and the increased risk of infection. To overcome these limitations, in the last few years a new kind of linear accelerator, the Novac 7, conceived for direct use in the surgical room, has become available. Novac 7 can deliver electron beams of different energies (3, 5, 7 and 9 MeV), with a high dose rate (up to 20 Gy/min). The aim of this work, funded by ENEA in the framework of a research contract, is the development of an innovative system for on-line measurements of 2D dose distributions and electron beam characterisation, before radiotherapy treatment with Novac 7. The system is made up of the following components: (a) an electron-light converter; (b) a 14 bit cooled CCD camera; (c) a personal computer with an ad hoc written software for image acquisition and processing. The performances of the prototype have been characterised experimentally with different electron-light converters. Several tests have concerned the assessment of the detector response as a function of impulse number and electron beam energy. Finally, the experimental results concerning beam profiles have been compared with data acquired with other dosimetric techniques. The achieved results make it possible to say that the developed system is suitable for fast quality assurance measurements and verification of 2D dose distributions.

  17. Low-noise heterodyne receiver for electron cyclotron emission imaging and microwave imaging reflectometry

    Energy Technology Data Exchange (ETDEWEB)

    Tobias, B., E-mail: bjtobias@pppl.gov [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Domier, C. W.; Luhmann, N. C.; Luo, C.; Mamidanna, M.; Phan, T.; Pham, A.-V.; Wang, Y. [University of California at Davis, Davis, California 95616 (United States)

    2016-11-15

    The critical component enabling electron cyclotron emission imaging (ECEI) and microwave imaging reflectometry (MIR) to resolve 2D and 3D electron temperature and density perturbations is the heterodyne imaging array that collects and downconverts radiated emission and/or reflected signals (50–150 GHz) to an intermediate frequency (IF) band (e.g. 0.1–18 GHz) that can be transmitted by a shielded coaxial cable for further filtering and detection. New circuitry has been developed for this task, integrating gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs) mounted on a liquid crystal polymer (LCP) substrate. The improved topology significantly increases electromagnetic shielding from out-of-band interference, leads to 10× improvement in the signal-to-noise ratio, and dramatic cost savings through integration. The current design, optimized for reflectometry and edge radiometry on mid-sized tokamaks, has demonstrated >20 dB conversion gain in upper V-band (60-75 GHz). Implementation of the circuit in a multi-channel electron cyclotron emission imaging (ECEI) array will improve the diagnosis of edge-localized modes and fluctuations of the high-confinement, or H-mode, pedestal.

  18. Multi-Mode Elastic Peak Electron Microscopy (MM-EPEM): A new imaging technique with an ultimate in-depth resolution for surface analysis.

    Science.gov (United States)

    Aymen Mahjoub, Mohamed; Monier, Guillaume; Bideux, Luc; Gruzza, Bernard; Robert-Goumet, Christine

    2018-05-01

    A non-destructive new imaging technique called Multi-Mode Elastic Peak Electron Microscopy (MM-EPEM), hypersensitive to surface chemistry and with an in-depth resolution of one atomic monolayer was developed. This method consists on performing several MM-EPEM images containing n × n pixels associated to an intensity of the elastic backscattered electrons by varying the incident electron energy in the range 200-2000 eV. This approach allows obtaining depth sampling information of the analyzed structures. Furthermore, MM-EPEM is associated with Monte-Carlo simulations describing the electron pathway in materials in order to obtain very precise quantitative information, for instance the growth mode and the organization of ultra-thin layers (2D materials) or nanoparticules. In this work, we used this new method to study the deposition of very small amount of gold down to one monolayer. Example of 3D reconstruction is also provided. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. 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.

  20. Understanding oxide interfaces: From microscopic imaging to electronic phases

    Science.gov (United States)

    Ilani, Shahal

    2014-03-01

    In the last decade, the advent of complex oxide interfaces has unleashed a wealth of new possibilities to create materials with unexpected functionalities. A notable example is the two-dimensional electron system formed at the interface between LaAlO3 and SrTiO3 (LAO/STO), which exhibits ferromagnetism, superconductivity, and a wide range of unique magneto-transport properties. A key challenge is to find the microscopic mechanisms that underlie these emergent phenomena. While there is a growing understanding that these phenomena might reflect rich structures at the micro-scale, experimental progress toward microscopic imaging of this system has been so far rather limited due to the buried nature of its interface. In this talk I will discuss our experiments that study this system on microscopic and macroscopic scales. Using a newly-developed nanotube-based scanning electrometer we image on the nanoscale the electrostatics and mechanics of this buried interface. We reveal the dynamics of structural domains in STO, their role in generating the contested anomalous piezoelectricity of this substrate, and their direct effects on the physics of the interface electrons. Using macroscopic magneto-transport experiments we demonstrate that a universal Lifshitz transition between the population of d-orbitals with different symmetries underlies many of the transport phenomena observed to date. We further show that the interactions between the itinerant electrons and localized spins leads to an unusual, gate-tunable magnetic phase diagram. These measurements highlight the unique physical settings that can be realized within this new class of low dimensional systems.

  1. Robust image alignment for cryogenic transmission electron microscopy.

    Science.gov (United States)

    McLeod, Robert A; Kowal, Julia; Ringler, Philippe; Stahlberg, Henning

    2017-03-01

    Cryo-electron microscopy recently experienced great improvements in structure resolution due to direct electron detectors with improved contrast and fast read-out leading to single electron counting. High frames rates enabled dose fractionation, where a long exposure is broken into a movie, permitting specimen drift to be registered and corrected. The typical approach for image registration, with high shot noise and low contrast, is multi-reference (MR) cross-correlation. Here we present the software package Zorro, which provides robust drift correction for dose fractionation by use of an intensity-normalized cross-correlation and logistic noise model to weight each cross-correlation in the MR model and filter each cross-correlation optimally. Frames are reliably registered by Zorro with low dose and defocus. Methods to evaluate performance are presented, by use of independently-evaluated even- and odd-frame stacks by trajectory comparison and Fourier ring correlation. Alignment of tiled sub-frames is also introduced, and demonstrated on an example dataset. Zorro source code is available at github.com/CINA/zorro. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Backscatter, anisotropy, and polarization of solar hard X-rays

    International Nuclear Information System (INIS)

    Bai, T.; Ramaty, R.

    1978-01-01

    Hard X-rays incident upon the photosphere with energies > or approx. =15 keV have high probabilities of backscatter due to Compton collisions with electrons. This effect has a strong influence on the spectrum, intensity, and polarization of solar hard X-rays - especially for anisotropic models in which the primary X-rays are emitted predominantly toward the photosphere. We have carried out a detailed study of X-ray backscatter, and we have investigated the interrelated problems of anisotropy, polarization, center-to-limb variation of the X-ray spectrum, and Compton backscatter in a coherent fashion. The results of this study are compared with observational data. Because of the large contribution from backscatter, for an anisotropic primary X-ray source which is due to bremsstrahlung of accelerated electrons moving predominantly down toward the photosphere, the observed X-ray flux around 30 keV does not depend significantly on the position of flare on the Sun. For such an anisotropic source, the X-ray spectrum observed in the 15-50 keV range becomes steeper with the increasing heliocentric angle of the flare. These results are compatible with the data. The degree of polarization of the sum of the primary and reflected X-rays with energies between about 15 and 30 keV can be very large for anisotropic primary X-ray sources, but it is less than about 4% for isotropic sources. We also discuss the characteristics of the brightness distribution of the X-ray albedo patch created by the Compton backscatter. The height and anisotropy of the primary hard X-ray source might be inferred from the study of the albedo patch

  3. Electron energy loss spectroscopy microanalysis and imaging in the transmission electron microscope: example of biological applications

    International Nuclear Information System (INIS)

    Diociaiuti, Marco

    2005-01-01

    This paper reports original results obtained in our laboratory over the past few years in the application of both electron energy loss spectroscopy (EELS) and electron spectroscopy imaging (ESI) to biological samples, performed in two transmission electron microscopes (TEM) equipped with high-resolution electron filters and spectrometers: a Gatan model 607 single magnetic sector double focusing EEL serial spectrometer attached to a Philips 430 TEM and a Zeiss EM902 Energy Filtering TEM. The primary interest was on the possibility offered by the combined application of these spectroscopic techniques with those offered by the TEM. In particular, the electron beam focusing available in a TEM allowed us to perform EELS and ESI on very small sample volumes, where high-resolution imaging and electron diffraction techniques can provide important structural information. I show that ESI was able to improve TEM performance, due to the reduced chromatic aberration and the possibility of avoiding the sample staining procedure. Finally, the analysis of the oscillating extended energy loss fine structure (EXELFS) beyond the ionization edges characterizing the EELS spectra allowed me, in a manner very similar to the extended X-ray absorption fine structure (EXAFS) analysis of the X-ray absorption spectra, to obtain short-range structural information for such light elements of biological interest as O or Fe. The Philips EM430 (250-300 keV) TEM was used to perform EELS microanalysis on Ca, P, O, Fe, Al and Si. The assessment of the detection limits of this method was obtained working with well-characterized samples containing Ca and P, and mimicking the actual cellular matrix. I applied EELS microanalysis to Ca detection in bone tissue during the mineralization process and to P detection in the cellular membrane of erythrocytes treated with an anti-tumoral drug, demonstrating that the cellular membrane is a drug target. I applied EELS microanalysis and selected area electron

  4. Backscattering technique to surface inspection

    International Nuclear Information System (INIS)

    Anjos, M.J. dos; Lopes, R.T.

    1989-01-01

    A new surface inspection system, starting of the backscattering of the gamma radiation is described. A cesium 137 source of 7,4x10 10 Bq (2Ci) and one cintillation detector are used. One calibration curve of the system was obtained. This technique can be very useful when the acess to one of the side of the object in inspection is limited. The scattering angle choosed was 115 0 . The object used was composed of aluminium, brass and stainless steel. The localization of defects is simple and ummediate. (V.R.B.)

  5. Chemical Reactions of Molecules Promoted and Simultaneously Imaged by the Electron Beam in Transmission Electron Microscopy.

    Science.gov (United States)

    Skowron, Stephen T; Chamberlain, Thomas W; Biskupek, Johannes; Kaiser, Ute; Besley, Elena; Khlobystov, Andrei N

    2017-08-15

    The main objective of this Account is to assess the challenges of transmission electron microscopy (TEM) of molecules, based on over 15 years of our work in this field, and to outline the opportunities in studying chemical reactions under the electron beam (e-beam). During TEM imaging of an individual molecule adsorbed on an atomically thin substrate, such as graphene or a carbon nanotube, the e-beam transfers kinetic energy to atoms of the molecule, displacing them from equilibrium positions. Impact of the e-beam triggers bond dissociation and various chemical reactions which can be imaged concurrently with their activation by the e-beam and can be presented as stop-frame movies. This experimental approach, which we term ChemTEM, harnesses energy transferred from the e-beam to the molecule via direct interactions with the atomic nuclei, enabling accurate predictions of bond dissociation events and control of the type and rate of chemical reactions. Elemental composition and structure of the reactant molecules as well as the operating conditions of TEM (particularly the energy of the e-beam) determine the product formed in ChemTEM processes, while the e-beam dose rate controls the reaction rate. Because the e-beam of TEM acts simultaneously as a source of energy for the reaction and as an imaging tool monitoring the same reaction, ChemTEM reveals atomic-level chemical information, such as pathways of reactions imaged for individual molecules, step-by-step and in real time; structures of illusive reaction intermediates; and direct comparison of catalytic activity of different transition metals filmed with atomic resolution. Chemical transformations in ChemTEM often lead to previously unforeseen products, demonstrating the potential of this method to become not only an analytical tool for studying reactions, but also a powerful instrument for discovery of materials that can be synthesized on preparative scale.

  6. Oscillations in the spectrum of nonlinear Thomson-backscattered radiation

    Directory of Open Access Journals (Sweden)

    C. A. Brau

    2004-02-01

    Full Text Available When an electron beam collides with a high-intensity laser beam, the spectrum of the nonlinear Thomson scattering in the backward direction shows strong oscillations like those in the spectrum of an optical klystron. Laser gain on the backward Thomson scattering is estimated using the Madey theorem, and the results suggest that Thomson-backscatter free-electron lasers are possible at wavelengths extending to the far uv using a terawatt laser beam from a chirped-pulse amplifier and a high-brightness electron beam from a needle cathode.

  7. Users guide to the HELIOS backscattering spectrometer (BSS)

    International Nuclear Information System (INIS)

    Bunce, L.J.

    1986-10-01

    The BSS is a backscattering spectrometer installed on the Harwell 136 Mev electron linear accelerator, HELIOS. A general description of the instrument is given, along with the time of flight scales, and the run and sample changer control units. The sample environment, vacuum system and detectors of the BSS are described, as well as the preparation, starting and running of an experiment using the BSS. (UK)

  8. Current profile reconstruction using electron temperature imaging diagnostics

    International Nuclear Information System (INIS)

    Tritz, K.; Stutman, D.; Delgado-Aparicio, L.F.; Finkenthal, M.; Pacella, D.; Kaita, R.; Stratton, B.; Sabbagh, S.

    2004-01-01

    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 T e 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 q 0 determined to within ±4%. The required SNR can be provided with either PHA or multicolor diagnostic techniques, though the multicolor system requires ∼x4 better statistics for comparable final errors

  9. Imaging photoelectron photoion coincidence spectroscopy with velocity focusing electron optics

    International Nuclear Information System (INIS)

    Bodi, Andras; Johnson, Melanie; Gerber, Thomas; Gengeliczki, Zsolt; Sztaray, Balint; Baer, Tomas

    2009-01-01

    An imaging photoelectron photoion coincidence spectrometer at the vacuum ultraviolet (VUV) beamline of the Swiss Light Source is presented and a few initial measurements are reported. Monochromatic synchrotron VUV radiation ionizes the cooled or thermal gas-phase sample. Photoelectrons are velocity focused, with better than 1 meV resolution for threshold electrons, and also act as start signal for the ion time-of-flight analysis. The ions are accelerated in a relatively low, 40-80 V cm -1 field, which enables the direct measurement of rate constants in the 10 3 -10 7 s -1 range. All electron and ion events are recorded in a triggerless multiple-start/multiple-stop setup, which makes it possible to carry out coincidence experiments at >100 kHz event frequencies. As examples, the threshold photoelectron spectrum of the argon dimer and the breakdown diagrams for hydrogen atom loss in room temperature methane and the chlorine atom loss in cold chlorobenzene are shown and discussed.

  10. The relationship between VHF radar auroral backscatter amplitude and Doppler velocity: a statistical study

    Directory of Open Access Journals (Sweden)

    B. A. Shand

    1996-08-01

    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.

  11. 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.

  12. Scanning ultrafast electron microscopy.

    Science.gov (United States)

    Yang, Ding-Shyue; Mohammed, Omar F; Zewail, Ahmed H

    2010-08-24

    Progress has been made in the development of four-dimensional ultrafast electron microscopy, which enables space-time imaging of structural dynamics in the condensed phase. In ultrafast electron microscopy, the electrons are accelerated, typically to 200 keV, and the microscope operates in the transmission mode. Here, we report the development of scanning ultrafast electron microscopy using a field-emission-source configuration. Scanning of pulses is made in the single-electron mode, for which the pulse contains at most one or a few electrons, thus achieving imaging without the space-charge effect between electrons, and still in ten(s) of seconds. For imaging, the secondary electrons from surface structures are detected, as demonstrated here for material surfaces and biological specimens. By recording backscattered electrons, diffraction patterns from single crystals were also obtained. Scanning pulsed-electron microscopy with the acquired spatiotemporal resolutions, and its efficient heat-dissipation feature, is now poised to provide in situ 4D imaging and with environmental capability.

  13. Large-field electron imaging and X-ray elemental mapping unveil the morphology, structure, and fractal features of a Cretaceous fossil at the centimeter scale.

    Science.gov (United States)

    Oliveira, Naiara C; Silva, João H; Barros, Olga A; Pinheiro, Allysson P; Santana, William; Saraiva, Antônio A F; Ferreira, Odair P; Freire, Paulo T C; Paula, Amauri J

    2015-10-06

    We used here a scanning electron microscopy approach that detected backscattered electrons (BSEs) and X-rays (from ionization processes) along a large-field (LF) scan, applied on a Cretaceous fossil of a shrimp (area ∼280 mm(2)) from the Araripe Sedimentary Basin. High-definition LF images from BSEs and X-rays were essentially generated by assembling thousands of magnified images that covered the whole area of the fossil, thus unveiling morphological and compositional aspects at length scales from micrometers to centimeters. Morphological features of the shrimp such as pleopods, pereopods, and antennae located at near-surface layers (undetected by photography techniques) were unveiled in detail by LF BSE images and in calcium and phosphorus elemental maps (mineralized as hydroxyapatite). LF elemental maps for zinc and sulfur indicated a rare fossilization event observed for the first time in fossils from the Araripe Sedimentary Basin: the mineralization of zinc sulfide interfacing to hydroxyapatite in the fossil. Finally, a dimensional analysis of the phosphorus map led to an important finding: the existence of a fractal characteristic (D = 1.63) for the hydroxyapatite-matrix interface, a result of physical-geological events occurring with spatial scale invariance on the specimen, over millions of years.

  14. Electron dose dependence of signal-to-noise ratio, atom contrast and resolution in transmission electron microscope images

    International Nuclear Information System (INIS)

    Lee, Z.; Rose, H.; Lehtinen, O.; Biskupek, J.; Kaiser, U.

    2014-01-01

    In order to achieve the highest resolution in aberration-corrected (AC) high-resolution transmission electron microscopy (HRTEM) images, high electron doses are required which only a few samples can withstand. In this paper we perform dose-dependent AC-HRTEM image calculations, and study the dependence of the signal-to-noise ratio, atom contrast and resolution on electron dose and sampling. We introduce dose-dependent contrast, which can be used to evaluate the visibility of objects under different dose conditions. Based on our calculations, we determine optimum samplings for high and low electron dose imaging conditions. - Highlights: • The definition of dose-dependent atom contrast is introduced. • The dependence of the signal-to-noise ratio, atom contrast and specimen resolution on electron dose and sampling is explored. • The optimum sampling can be determined according to different dose conditions

  15. Fiber taper characterization by optical backscattering reflectometry.

    Science.gov (United States)

    Lai, Yu-Hung; Yang, Ki Youl; Suh, Myoung-Gyun; Vahala, Kerry J

    2017-09-18

    Fiber tapers provide a way to rapidly measure the spectra of many types of optical microcavities. Proper fabrication of the taper ensures that its width varies sufficiently slowly (adiabatically) along the length of the taper so as to maintain single spatial mode propagation. This is usually accomplished by monitoring the spectral transmission through the taper. In addition to this characterization method it is also helpful to know the taper width versus length. By developing a model of optical backscattering within the fiber taper, it is possible to use backscatter measurements to characterize the taper width versus length. The model uses the concept of a local taper numerical aperture to accurately account for varying backscatter collection along the length of the taper. In addition to taper profile information, the backscatter reflectometry method delineates locations along the taper where fluctuations in fiber core refractive index, cladding refractive index, and taper surface roughness each provide the dominant source of backscattering. Rayleigh backscattering coefficients are also extracted by fitting the data with the model and are consistent with the fiber manufacturer's datasheet. The optical backscattering reflectometer is also used to observe defects resulting from microcracks and surface contamination. All of this information can be obtained before the taper is removed from its fabrication apparatus. The backscattering method should also be prove useful for characterization of nanofibers.

  16. Producing Science-Ready Radar Datasets for the Retrieval of Forest Structure Parameters from Backscatter: Correcting for Terrain Topography and Changes in Vegetation Reflectivity

    Science.gov (United States)

    Simard, M.; Riel, Bryan; Hensley, S.; Lavalle, Marco

    2011-01-01

    Radar backscatter data contain both geometric and radiometric distortions due to underlying topography and the radar viewing geometry. Our objective is to develop a radiometric correction algorithm specific to the UAVSAR system configuration that would improve retrieval of forest structure parameters. UAVSAR is an airborne Lband radar capable of repeat?pass interferometry producing images with a spatial resolution of 5m. It is characterized by an electronically steerable antenna to compensate for aircraft attitude. Thus, the computation of viewing angles (i.e. look, incidence and projection) must include aircraft attitude angles (i.e. yaw, pitch and roll) in addition to the antenna steering angle. In this presentation, we address two components of radiometric correction: area projection and vegetation reflectivity. The first correction is applied by normalization of the radar backscatter by the local ground area illuminated by the radar beam. The second is a correction due to changes in vegetation reflectivity with viewing geometry.

  17. 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

  18. Interferometric evidence for the observation of ground backscatter originating behind the CUTLASS coherent HF radars

    Directory of Open Access Journals (Sweden)

    S. E. Milan

    1997-01-01

    Full Text Available Interferometric techniques allow the SuperDARN coherent HF radars to determine the elevation angles of returned backscatter, giving information on the altitude of the scatter volume, in the case of ionospheric backscatter, or the reflection altitude, in the case of ground backscatter. Assumptions have to be made in the determination of elevation angles, including the direction of arrival, or azimuth, of the returned signals, usually taken to be the forward look-direction (north of the radars, specified by the phasing of the antenna arrays. It is shown that this assumption is not always valid in the case of ground backscatter, and that significant returns can be detected from the backward look-direction of the radars. The response of the interferometer to backscatter from behind the radar is modelled and compared with observations. It is found that ground backscatter from a field-of-view that is the mirror image of the forward-looking field-of-view is a common feature of the observations, and this interpretation successfully explains several anomalies in the received backscatter.

  19. Interferometric evidence for the observation of ground backscatter originating behind the CUTLASS coherent HF radars

    Directory of Open Access Journals (Sweden)

    S. E. Milan

    Full Text Available Interferometric techniques allow the SuperDARN coherent HF radars to determine the elevation angles of returned backscatter, giving information on the altitude of the scatter volume, in the case of ionospheric backscatter, or the reflection altitude, in the case of ground backscatter. Assumptions have to be made in the determination of elevation angles, including the direction of arrival, or azimuth, of the returned signals, usually taken to be the forward look-direction (north of the radars, specified by the phasing of the antenna arrays. It is shown that this assumption is not always valid in the case of ground backscatter, and that significant returns can be detected from the backward look-direction of the radars. The response of the interferometer to backscatter from behind the radar is modelled and compared with observations. It is found that ground backscatter from a field-of-view that is the mirror image of the forward-looking field-of-view is a common feature of the observations, and this interpretation successfully explains several anomalies in the received backscatter.

  20. Gas-Filled Targets to Study Laser Backscatter on the National Ignition Facility

    Science.gov (United States)

    London, R. A.; Williams, E. A.; Hinkel, D. E.; Moody, J. D.; Suter, L. J.

    2009-11-01

    To achieve indirect drive fusion at the National Ignition Facility (NIF), laser beams must propagate through several millimeters of high-density plasma to reach the hohlraum walls. Stimulated Brillouin and Raman backscatter could create problems with energetics and/or symmetry. Laser backscatter at NIF will be diagnosed with full aperture backscatter systems (FABS) and near backscatter imagers (NBI). Several gas-filled targets (``gas pipes'') have been designed to provide backscatter sources to commission the diagnostics. The 7-mm long gas pipes are filled with various gases, including C5H12 and CO2, and are irradiated by a NIF quad with 16 kJ of energy in 2-4 ns pulses. We describe the design of the gas pipes using hydrodynamics and laser-plasma-interaction computer codes. The relationship between the design parameters (gas composition and density and laser pulse shape) and the character of the backscatter (Brillouin versus Raman and narrow versus broad angle) are discussed. Comparisons of predicted and measured backscatter distributions and levels are discussed.

  1. Nicotiana Occidentalis Chloroplast Ultrastructure imaged with Transmission Electron Microscopes Working at Different Accelerating Voltages

    OpenAIRE

    SVIDENSKÁ, Silvie

    2010-01-01

    The main goal of this thesis is to study and compare electron microscopy images of Nicotiana Occidentalis chloroplasts, obtained from two types of transmission electron microscopes,which work with different accelerating voltage of 80kV and 5kV. The two instruments, TEM JEOL 1010 and low voltage electron microscope LVEM5 are employed for experiments. In the first theoretical part, principle of electron microscopy and chloroplast morphology is described. In experimental part, electron microscop...

  2. 77 FR 32995 - Certain Electronic Imaging Devices Corrected: Notice of Receipt of Complaint; Solicitation of...

    Science.gov (United States)

    2012-06-04

    ... INTERNATIONAL TRADE COMMISSION [Docket No. 2898] Certain Electronic Imaging Devices Corrected.... International Trade Commission. ACTION: Notice. SUMMARY: Notice is hereby given that the U.S. International Trade Commission has received a complaint entitled Certain Electronic Imaging Devices, DN 2898; the...

  3. 77 FR 31875 - Certain Electronic Imaging Devices; Notice of Receipt of Complaint; Solicitation of Comments...

    Science.gov (United States)

    2012-05-30

    ... INTERNATIONAL TRADE COMMISSION [Docket No. 2898] Certain Electronic Imaging Devices; Notice of... Trade Commission. ACTION: Notice. SUMMARY: Notice is hereby given that the U.S. International Trade Commission has received a complaint entitled Certain Electronic Imaging Devices, DN 2898; the Commission is...

  4. Laboratory experiments on backscattering from regolith samples

    Science.gov (United States)

    Kaasalainen, Sanna; Piironen, Jukka; Muinonen, Karri; Karttunen, Hannu; Peltoniemi, Jouni

    2002-07-01

    The investigation of the backscattering peak has applications in the surface texture characterization of asteroids and planetary surfaces. Laboratory experiments are important because they give an opportunity for systematic variation and comparison of samples. A backscattering experiment from regolith samples, which uses a laser light source and a beam splitter to reach the smallest phase angles, is presented. Measurements at zero and small phase angles for Sahara sand and meteorite rocks are made, and the preliminary results are presented in comparison with the phase curve observed for asteroid 69 Hesperia. The results are applicable to the further interpretation of the coherent backscattering opposition effect.

  5. 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.

  6. Technical characterization by image analysis: an automatic method of mineralogical studies

    International Nuclear Information System (INIS)

    Oliveira, J.F. de

    1988-01-01

    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) [pt

  7. Athermal electron distribution probed by femtosecond multiphoton photoemission from image potential states

    International Nuclear Information System (INIS)

    Ferrini, Gabriele; Giannetti, Claudio; Pagliara, Stefania; Banfi, Francesco; Galimberti, Gianluca; Parmigiani, Fulvio

    2005-01-01

    Image potential states are populated through indirect, scattering-mediated multiphoton absorption induced by femtosecond laser pulses and revealed by single-photon photoemission. The measured effective mass is significantly different from that obtained with direct, resonant population. These features reveal a strong coupling of the electrons residing in the image potential state, outside the solid, with the underlying hot electron population created by the laser pulse. The coupling is mediated by a many-body scattering interaction between the image potential state electrons and bulk electrons in highly excited states

  8. Assessing the contamination of SuperDARN global convection maps by non-F-region backscatter

    Directory of Open Access Journals (Sweden)

    G. Chisham

    2002-01-01

    Full Text Available Global convection mapping using line-of-sight Doppler velocity data from the Super Dual Auroral Radar Network (SuperDARN is now an accepted method of imaging high-latitude ionospheric convection. This mapping process requires that the flow measured by the radars is defined solely by the convection electric field. This is generally only true of radar backscatter from the ionospheric F-region. We investigate the extent to which the E-region and ground backscatter in the SuperDARN data set may be misidentified as F-region backscatter, and assess the contamination of global convection maps which results from the addition of this non-F-region backscatter. We present examples which highlight the importance of identifying this contamination, especially with regard to the mesoscale structure in the convection maps.Key words. Ionosphere (plasma convection – Radio science (radio wave propagation; instruments and techniques

  9. New electronic imaging system for Cf-252 based neutron radiography

    International Nuclear Information System (INIS)

    Ito, S.; Mochiki, K.; Matsumoto, T.

    2004-01-01

    We have developed a new imaging camera and a signal processing system for Cf-252 based neutron radiography. The imaging part consists of cascaded image intensifiers and a progressive-scan monochromatic CCD camera (SONY XC-55) with standard frame rate. The video signal is converted to 12 bits and processed by large-scale field programmable arrays (FPGAs). The signal processing system has three frame accumulation memories for normal frame images, binary-converted frame images and center-of-gravity frame images. A preliminary experiment was made using a Cf-252 neutron source at Atomic Energy Research Laboratory of Musashi Institute of Technology. (author)

  10. Problems during the determination of grain-sizes in austenitic plates by the application of ultrasonic-backscattering

    International Nuclear Information System (INIS)

    Hecht, A.; Neumann, E.; Mundry, E.; Thiel, R.

    1980-01-01

    Ultrasonic backscattering makes possible the nondestructive determination of grain size in austenitic strips. In immersion technique a short pulse is sent into the material and the backscattered sound-amplitude is measured. When using a calibration curve, grain sizes can be calculated from the backscattered sound-amplitudes. There are problems in practical use because of mechanical and electronical data having an influence on the results of measurement. An exact determination of grain size depends on accurate mechanical adjustment and on stability of the electronical equipment, too. (orig.) [de

  11. Electronic noise in CT detectors: Impact on image noise and artifacts.

    Science.gov (United States)

    Duan, Xinhui; Wang, Jia; Leng, Shuai; Schmidt, Bernhard; Allmendinger, Thomas; Grant, Katharine; Flohr, Thomas; McCollough, Cynthia H

    2013-10-01

    The objective of our study was to evaluate in phantoms the differences in CT image noise and artifact level between two types of commercial CT detectors: one with distributed electronics (conventional) and one with integrated electronics intended to decrease system electronic noise. Cylindric water phantoms of 20, 30, and 40 cm in diameter were scanned using two CT scanners, one equipped with integrated detector electronics and one with distributed detector electronics. All other scanning parameters were identical. Scans were acquired at four tube potentials and 10 tube currents. Semianthropomorphic phantoms were scanned to mimic the shoulder and abdominal regions. Images of two patients were also selected to show the clinical values of the integrated detector. Reduction of image noise with the integrated detector depended on phantom size, tube potential, and tube current. Scans that had low detected signal had the greatest reductions in noise, up to 40% for a 30-cm phantom scanned using 80 kV. This noise reduction translated into up to 50% in dose reduction to achieve equivalent image noise. Streak artifacts through regions of high attenuation were reduced by up to 45% on scans obtained using the integrated detector. Patient images also showed superior image quality for the integrated detector. For the same applied radiation level, the use of integrated electronics in a CT detector showed a substantially reduced level of electronic noise, resulting in reductions in image noise and artifacts, compared with detectors having distributed electronics.

  12. 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)

  13. SMAPVEX08 PALS Backscatter Data V001

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains backscatter data obtained by the Passive Active L-band System (PALS) microwave aircraft radar instrument as part of the Soil Moisture Active...

  14. 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....

  15. 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...

  16. 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 Team...

  17. NOAA ESRI Geotiff - 3m Backscatter Mosaic, Puerto Rico (Isla de Vieques) - UTM 20N NAD83 (NCEI Accession 0131852)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 3 meter resolution backscatter mosaic of selected portions of seafloor around Isla de Vieques, Puerto Rico. NOAA's NOS/NCCOS/CCFHR, in...

  18. 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.)

  19. Single atom image observation by means of scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Komoda, Tsutomu; Todokoro, Hideo; Nomura, Setsuo

    1977-01-01

    In a scanning transmission electron microscope, electrons emitted from the ion source are finely focused to a spot on a specimen, and scanned with the deflection coil. The electrons transmitted through the specimen are detected by the scintillate, and converted to image signals with the photomultiplier, and the image is obtained on the cathode ray tube. The Hitachi scanning transmission electron microscope employs a field emission type electron gun, thus it can focus the electron beam to 0.3 nm diameter. In the microscope, elastically scattered electrons are captured by a doughnut shaped detector, while the electrons transmitted through the specimen without colliding with atoms and the non-elastically scattered electrons which has lost a part of their energy due to the ionization or excitation of atoms are detected by the energy analyzer installed at the bottom of the microscope. Though single atom image observation requires the fixation of the atoms to be marked on a support, the problem is how to discriminate the aimed atoms from the atoms of the support. The most sensitive method is the dark-field method which uses the difference of elastically scattered electron intensity as the signal. Thorium and iodine atom images have been successfully observed as the trials to prove the feasibility of observation of heavy atoms with the scanning transmission electron microscope. (Wakatsuki, Y.)

  20. Image formation mechanisms in scanning electron microscopy of carbon nanotubes, and retrieval of their intrinsic dimensions.

    Science.gov (United States)

    Jackman, H; Krakhmalev, P; Svensson, K

    2013-01-01

    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. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Electron beam imaging and spectroscopy of plasmonic nanoantenna resonances

    Science.gov (United States)

    Vesseur, E. J. R.

    2011-07-01

    Nanoantennas are metal structures that provide strong optical coupling between a nanoscale volume and the far field. This coupling is mediated by surface plasmons, oscillations of the free electrons in the metal. Increasing the control over the resonant plasmonic field distribution opens up a wide range of applications of nanoantennas operating both in receiving and transmitting mode. This thesis presents how the dispersion and confinement of surface plasmons in nanoantennas are resolved and further engineered. Fabrication of nanostructures is done using focused ion beam milling (FIB) in metallic surfaces. We demonstrate that patterning in single-crystal substrates allows us to precisely control the geometry in which plasmons are confined. The nanoscale properties of the resonant plasmonic fields are resolved using a new technique developed in this thesis: angle- and polarization controlled cathodoluminescence (CL) imaging spectroscopy. The use of a tightly focused electron beam allows us to probe the optical antenna properties with deep subwavelength resolution. We show using this technique that nanoantennas consisting of 500-1200 nm long polycrystalline Au nanowires support standing plasmon waves. We directly observe the plasmon wavelengths which we use to derive the dispersion relation of guided nanowire plasmons. A 590-nm-long ridge-shaped nanoantenna was fabricated using FIB milling on a single-crystal Au substrate, demonstrating a level of control over the fabrication impossible with polycrystalline metals. CL experiments show that the ridge supports multiple-order resonances. The confinement of surface plasmons to the ridge is confirmed by boundary-element-method (BEM) calculations. The resonant modes in plasmonic whispering gallery cavities consisting of a FIB-fabricated circular groove are resolved. We find an excellent agreement between boundary element method calculations and the measured CL emission from the ring-shaped cavities. The calculations show

  2. SPR imaging based electronic tongue via landscape images for complex mixture analysis.

    Science.gov (United States)

    Genua, Maria; Garçon, Laurie-Amandine; Mounier, Violette; Wehry, Hillary; Buhot, Arnaud; Billon, Martial; Calemczuk, Roberto; Bonnaffé, David; Hou, Yanxia; Livache, Thierry

    2014-12-01

    Electronic noses/tongues (eN/eT) have emerged as promising alternatives for analysis of complex mixtures in the domain of food and beverage quality control. We have recently developed an electronic tongue by combining surface plasmon resonance imaging (SPRi) with an array of non-specific and cross-reactive receptors prepared by simply mixing two small molecules in varying and controlled proportions and allowing the mixtures to self-assemble on the SPRi prism surface. The obtained eT generated novel and unique 2D continuous evolution profiles (CEPs) and 3D continuous evolution landscapes (CELs) based on which the differentiation of complex mixtures such as red wine, beer and milk were successful. The preliminary experiments performed for monitoring the deterioration of UHT milk demonstrated its potential for quality control applications. Furthermore, the eT exhibited good repeatability and stability, capable of operating after a minimum storage period of 5 months. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Electronically shuttered camera system for the acquisition of precise images

    Science.gov (United States)

    Struck, Jacob K.

    1992-08-01

    An accuracy requirement of +/-0.011 degrees in the declination measurement of a remotely imaged munition cannot be satisfied using a conventional camera. A camera, error characterization, and error correction techniques are designed and developed that satisfy the accuracy requirement. The images are acquired and processed using an ARDEC developed data acquisition and image processing system. Based on internal testing, the developed system is expected to meet design goals during a formal certification process.

  4. From Relativistic Electrons to X-ray Phase Contrast Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A. H. [Fermilab; Garson, A. B. [Washington U., St. Louis; Anastasio, M. A. [Washington U., St. Louis

    2017-10-09

    We report the initial demonstrations of the use of single crystals in indirect x-ray imaging for x-ray phase contrast imaging at the Washington University in St. Louis Computational Bioimaging Laboratory (CBL). Based on single Gaussian peak fits to the x-ray images, we observed a four times smaller system point spread function (21 μm (FWHM)) with the 25-mm diameter single crystals than the reference polycrystalline phosphor’s 80-μm value. Potential fiber-optic plate depth-of-focus aspects and 33-μm diameter carbon fiber imaging are also addressed.

  5. Novel X-ray backscatter technique for detection of dangerous materials: application to aviation and port security

    International Nuclear Information System (INIS)

    Kolkoori, S; Wrobel, N; Osterloh, K; Zscherpel, U; Ewert, U

    2013-01-01

    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

  6. Novel X-ray backscatter technique for detection of dangerous materials: application to aviation and port security

    Science.gov (United States)

    Kolkoori, S.; Wrobel, N.; Osterloh, K.; Zscherpel, U.; Ewert, U.

    2013-09-01

    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.

  7. Electron microscope image contrast from small dislocation loops

    International Nuclear Information System (INIS)

    Holmes, S.M.; Eyre, B.L.; English, C.A.; Perrin, R.C.

    1979-01-01

    The theoretical study of image contrast from small finite dislocation loops in an isotropic BCC crystal, reported in parts I and II, has been extended to include non-edge loops. Computer image simulation has again been used to study the influence of loop normal, n, Burger's vector, b, diffraction vector, g, and image plane normal, z, on the distribution of black-white intensities in images from loops located in layer 1, i.e. within 0.25 xisub(g) of the surface, where xisub(g) is the extinction distance for the diffracting vector g. As before, the choice and range of parameters have been determined by the authors' interest in radiation damage in BCC molybdenum. The main conclusion from a survey of non-edge perfect loop images is that modifications are predicted to the images from edge loops on going to the non-edge configuration, but that in the majority of cases the scheme of image classification introduced for edge loops based on /g.b/ is still appropriate. Generally, the modifications to the edge images take the form of some skewing of the black-white lobes or rotation of the black-white interface. In particular, it was found that, firstly, the images where /g.b/ > 1 always retain their characteristic interface structure between the black and white lobes. Secondly, the g.b = 0 images from loops with b normal to z may be distorted significantly from the symmetrical 'butterfly' obtained from pure edge loops and, thirdly, for some specific combinations of g, b, n and z, difficulty is encountered in distinguishing between modified g.b = 0 and 0 < /g.b/ < 1 images. Lastly, the application of these results to the experimental determination of b and n is discussed. (author)

  8. Quantitative Analysis of Venus Radar Backscatter Data in ArcGIS

    Science.gov (United States)

    Long, S. M.; Grosfils, E. B.

    2005-01-01

    Ongoing mapping of the Ganiki Planitia (V14) quadrangle of Venus and definition of material units has involved an integrated but qualitative analysis of Magellan radar backscatter images and topography using standard geomorphological mapping techniques. However, such analyses do not take full advantage of the quantitative information contained within the images. Analysis of the backscatter coefficient allows a much more rigorous statistical comparison between mapped units, permitting first order selfsimilarity tests of geographically separated materials assigned identical geomorphological labels. Such analyses cannot be performed directly on pixel (DN) values from Magellan backscatter images, because the pixels are scaled to the Muhleman law for radar echoes on Venus and are not corrected for latitudinal variations in incidence angle. Therefore, DN values must be converted based on pixel latitude back to their backscatter coefficient values before accurate statistical analysis can occur. Here we present a method for performing the conversions and analysis of Magellan backscatter data using commonly available ArcGIS software and illustrate the advantages of the process for geological mapping.

  9. MEASURING THE PARTICULATE BACKSCATTERING OF INLAND WATERS: A COMPARISON OF TECHNIQUES

    Directory of Open Access Journals (Sweden)

    G. Campbell

    2012-07-01

    Full Text Available The objective of this work was to examine whether the standard particulate backscattering IOP (Inherent Optical Properties measurement method could be simplified. IOP measurements are essential for parameterising several forms of algorithms used to estimate water quality parameters from airborne and satellite images. Field measurements of the backscattering IOPs are more difficult to make than absorption measurements as correction of the raw Hydroscat-6 backscattering sensor observations is required to allow for the systematic errors associated with the water and water quality parameter absorption. The standard approach involves making simultaneous measurement of the absorption and attenuation of the water with an absorption and attenuation meter (ac-9 or making assumptions about the particulate backscattering probability. Recently, a number of papers have been published that use an alternative method to retrieve the particulate backscattering spectrum by using laboratory measured absorption values and in situ spectroradiometric observations. The alternative method inverts a model of reflectance iteratively using non-linear least squares fitting to solve for the particulate backscattering at 532 nm (bbp0(532 and the particulate backscattering spectral slope (γ. In this paper, eleven observations made at Burdekin Falls Dam, Australia are used to compare the alternative reflectance method to the conventional corrected Hydroscat-6 observations. Assessment of the alternative reflectance method showed that the result of the inversions were highly dependent on the starting conditions. To overcome this limitation, Particle Swarm Optimisation, a stochastic search technique which includes a random element in the search approach, was used. It was found that when compared to the conventionally corrected Hydroscat-6 observations, the alternative reflectance method underestimated bbp0(532 by approximately 50% and overestimated γ by approximately 40

  10. Prototype system for proton beam range measurement based on gamma electron vertex imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Han Rim [Neutron Utilization Technology Division, Korea Atomic Energy Research Institute, 111, Daedeok-daero 989beon-gil, Yuseong-gu, Daejeon 34057 (Korea, Republic of); Kim, Sung Hun; Park, Jong Hoon [Department of Nuclear Engineering, Hanyang University, Seongdong-gu, Seoul 04763 (Korea, Republic of); Jung, Won Gyun [Heavy-ion Clinical Research Division, Korean Institute of Radiological & Medical Sciences, Seoul 01812 (Korea, Republic of); Lim, Hansang [Department of Electronics Convergence Engineering, Kwangwoon University, Seoul 01897 (Korea, Republic of); Kim, Chan Hyeong, E-mail: chkim@hanyang.ac.kr [Department of Nuclear Engineering, Hanyang University, Seongdong-gu, Seoul 04763 (Korea, Republic of)

    2017-06-11

    In proton therapy, for both therapeutic effectiveness and patient safety, it is very important to accurately measure the proton dose distribution, especially the range of the proton beam. For this purpose, recently we proposed a new imaging method named gamma electron vertex imaging (GEVI), in which the prompt gammas emitting from the nuclear reactions of the proton beam in the patient are converted to electrons, and then the converted electrons are tracked to determine the vertices of the prompt gammas, thereby producing a 2D image of the vertices. In the present study, we developed a prototype GEVI system, including dedicated signal processing and data acquisition systems, which consists of a beryllium plate (= electron converter) to convert the prompt gammas to electrons, two double-sided silicon strip detectors (= hodoscopes) to determine the trajectories of those converted electrons, and a plastic scintillation detector (= calorimeter) to measure their kinetic energies. The system uses triple coincidence logic and multiple energy windows to select only the events from prompt gammas. The detectors of the prototype GEVI system were evaluated for electronic noise level, energy resolution, and time resolution. Finally, the imaging capability of the GEVI system was tested by imaging a {sup 90}Sr beta source, a {sup 60}Co gamma source, and a 45-MeV proton beam in a PMMA phantom. The overall results of the present study generally show that the prototype GEVI system can image the vertices of the prompt gammas produced by the proton nuclear interactions.

  11. Prototype system for proton beam range measurement based on gamma electron vertex imaging

    Science.gov (United States)

    Lee, Han Rim; Kim, Sung Hun; Park, Jong Hoon; Jung, Won Gyun; Lim, Hansang; Kim, Chan Hyeong

    2017-06-01

    In proton therapy, for both therapeutic effectiveness and patient safety, it is very important to accurately measure the proton dose distribution, especially the range of the proton beam. For this purpose, recently we proposed a new imaging method named gamma electron vertex imaging (GEVI), in which the prompt gammas emitting from the nuclear reactions of the proton beam in the patient are converted to electrons, and then the converted electrons are tracked to determine the vertices of the prompt gammas, thereby producing a 2D image of the vertices. In the present study, we developed a prototype GEVI system, including dedicated signal processing and data acquisition systems, which consists of a beryllium plate (= electron converter) to convert the prompt gammas to electrons, two double-sided silicon strip detectors (= hodoscopes) to determine the trajectories of those converted electrons, and a plastic scintillation detector (= calorimeter) to measure their kinetic energies. The system uses triple coincidence logic and multiple energy windows to select only the events from prompt gammas. The detectors of the prototype GEVI system were evaluated for electronic noise level, energy resolution, and time resolution. Finally, the imaging capability of the GEVI system was tested by imaging a 90Sr beta source, a 60Co gamma source, and a 45-MeV proton beam in a PMMA phantom. The overall results of the present study generally show that the prototype GEVI system can image the vertices of the prompt gammas produced by the proton nuclear interactions.

  12. Proposed imaging of the ultrafast electronic motion in samples using x-ray phase contrast.

    Science.gov (United States)

    Dixit, Gopal; Slowik, Jan Malte; Santra, Robin

    2013-03-29

    Tracing the motion of electrons has enormous relevance to understanding ubiquitous phenomena in ultrafast science, such as the dynamical evolution of the electron density during complex chemical and biological processes. Scattering of ultrashort x-ray pulses from an electronic wave packet would appear to be the most obvious approach to image the electronic motion in real time and real space with the notion that such scattering patterns, in the far-field regime, encode the instantaneous electron density of the wave packet. However, recent results by Dixit et al. [Proc. Natl. Acad. Sci. U.S.A. 109, 11636 (2012)] have put this notion into question and have shown that the scattering in the far-field regime probes spatiotemporal density-density correlations. Here, we propose a possible way to image the instantaneous electron density of the wave packet via ultrafast x-ray phase contrast imaging. Moreover, we show that inelastic scattering processes, which plague ultrafast scattering in the far-field regime, do not contribute in ultrafast x-ray phase contrast imaging as a consequence of an interference effect. We illustrate our general findings by means of a wave packet that lies in the time and energy range of the dynamics of valence electrons in complex molecular and biological systems. This present work offers a potential to image not only instantaneous snapshots of nonstationary electron dynamics, but also the laplacian of these snapshots which provide information about the complex bonding and topology of the charge distributions in the systems.

  13. Electron-beam lithography simulation for mask making: VI. Comparison of 10- and 50-kV GHOST proximity effect correction

    Science.gov (United States)

    Mack, Chris A.

    2001-09-01

    GHOST uses two exposures, the primary dose and its complement, in an attempt to equalize the effects of backscattering and reduce proximity effects. Unfortunately, image contrast is reduced compared to exposures done without GHOST. A simplified raster scan theory is developed in order to examine the effects of backscattering and GHOST proximity correction on the quality of the images produced. Electron beam lithography simulation is used to examine the effect of spot size and voltage on the spot image generated in 400 nm of ZEP 7000 resist, and the effects of GHOST on proximity effects and process latitude.

  14. Atomically resolved real-space imaging of hot electron dynamics

    Science.gov (United States)

    Lock, D.; Rusimova, K. R.; Pan, T. L.; Palmer, R. E.; Sloan, P. A.

    2015-01-01

    The dynamics of hot electrons are central to understanding the properties of many electronic devices. But their ultra-short lifetime, typically 100 fs or less, and correspondingly short transport length-scale in the nanometre range constrain real-space investigations. Here we report variable temperature and voltage measurements of the nonlocal manipulation of adsorbed molecules on the Si(111)-7 × 7 surface in the scanning tunnelling microscope. The range of the nonlocal effect increases with temperature and, at constant temperature, is invariant over a wide range of electron energies. The measurements probe, in real space, the underlying hot electron dynamics on the 10 nm scale and are well described by a two-dimensional diffusive model with a single decay channel, consistent with 2-photon photo-emission (2PPE) measurements of the real time dynamics. PMID:26387703

  15. Design of a cathodoluminescence image generator using a Raspberry Pi coupled to a scanning electron microscope

    Science.gov (United States)

    Benítez, Alfredo; Santiago, Ulises; Sanchez, John E.; Ponce, Arturo

    2018-01-01

    In this work, an innovative cathodoluminescence (CL) system is coupled to a scanning electron microscope and synchronized with a Raspberry Pi computer integrated with an innovative processing signal. The post-processing signal is based on a Python algorithm that correlates the CL and secondary electron (SE) images with a precise dwell time correction. For CL imaging, the emission signal is collected through an optical fiber and transduced to an electrical signal via a photomultiplier tube (PMT). CL Images are registered in a panchromatic mode and can be filtered using a monochromator connected between the optical fiber and the PMT to produce monochromatic CL images. The designed system has been employed to study ZnO samples prepared by electrical arc discharge and microwave methods. CL images are compared with SE images and chemical elemental mapping images to correlate the emission regions of the sample.

  16. Design of a cathodoluminescence image generator using a Raspberry Pi coupled to a scanning electron microscope.

    Science.gov (United States)

    Benítez, Alfredo; Santiago, Ulises; Sanchez, John E; Ponce, Arturo

    2018-01-01

    In this work, an innovative cathodoluminescence (CL) system is coupled to a scanning electron microscope and synchronized with a Raspberry Pi computer integrated with an innovative processing signal. The post-processing signal is based on a Python algorithm that correlates the CL and secondary electron (SE) images with a precise dwell time correction. For CL imaging, the emission signal is collected through an optical fiber and transduced to an electrical signal via a photomultiplier tube (PMT). CL Images are registered in a panchromatic mode and can be filtered using a monochromator connected between the optical fiber and the PMT to produce monochromatic CL images. The designed system has been employed to study ZnO samples prepared by electrical arc discharge and microwave methods. CL images are compared with SE images and chemical elemental mapping images to correlate the emission regions of the sample.

  17. General filtering method for electronic speckle pattern interferometry fringe images with various densities based on variational image decomposition.

    Science.gov (United States)

    Li, Biyuan; Tang, Chen; Gao, Guannan; Chen, Mingming; Tang, Shuwei; Lei, Zhenkun

    2017-06-01

    Filtering off speckle noise from a fringe image is one of the key tasks in electronic speckle pattern interferometry (ESPI). In general, ESPI fringe images can be divided into three categories: low-density fringe images, high-density fringe images, and variable-density fringe images. In this paper, we first present a general filtering method based on variational image decomposition that can filter speckle noise for ESPI fringe images with various densities. In our method, a variable-density ESPI fringe image is decomposed into low-density fringes, high-density fringes, and noise. A low-density fringe image is decomposed into low-density fringes and noise. A high-density fringe image is decomposed into high-density fringes and noise. We give some suitable function spaces to describe low-density fringes, high-density fringes, and noise, respectively. Then we construct several models and numerical algorithms for ESPI fringe images with various densities. And we investigate the performance of these models via our extensive experiments. Finally, we compare our proposed models with the windowed Fourier transform method and coherence enhancing diffusion partial differential equation filter. These two methods may be the most effective filtering methods at present. Furthermore, we use the proposed method to filter a collection of the experimentally obtained ESPI fringe images with poor quality. The experimental results demonstrate the performance of our proposed method.

  18. Guiding the Design of Radiation Imagers with Experimentally Benchmarked Geant4 Simulations for Electron-Tracking Compton Imaging

    Science.gov (United States)

    Coffer, Amy Beth

    Radiation imagers are import tools in the modern world for a wide range of applications. They span the use-cases of fundamental sciences, astrophysics, medical imaging, all the way to national security, nuclear safeguards, and non-proliferation verification. The type of radiation imagers studied in this thesis were gamma-ray imagers that detect emissions from radioactive materials. Gamma-ray imagers goal is to localize and map the distribution of radiation within their specific field-of-view despite the fact of complicating background radiation that can be terrestrial, astronomical, and temporal. Compton imaging systems are one type of gamma-ray imager that can map the radiation around the system without the use of collimation. Lack of collimation enables the imaging system to be able to detect radiation from all-directions, while at the same time, enables increased detection efficiency by not absorbing incident radiation in non-sensing materials. Each Compton-scatter events within an imaging system generated a possible cone-surface in space that the radiation could have originated from. Compton imaging is limited in its reconstructed image signal-to-background due to these source Compton-cones overlapping with background radiation Compton-cones. These overlapping cones limit Compton imaging's detection-sensitivity in image space. Electron-tracking Compton imaging (ETCI) can improve the detection-sensitivity by measuring the Compton-scattered electron's initial trajectory. With an estimate of the scattered electron's trajectory, one can reduce the Compton-back-projected cone to a cone-arc, thus enabling faster radiation source detection and localization. However, the ability to measure the Compton-scattered electron-trajectories adds another layer of complexity to an already complex methodology. For a real-world imaging applications, improvements are needed in electron-track detection efficiency and in electron-track reconstruction. One way of measuring Compton

  19. Comparative study of image contrast in scanning electron microscope and helium ion microscope.

    Science.gov (United States)

    O'Connell, R; Chen, Y; Zhang, H; Zhou, Y; Fox, D; Maguire, P; Wang, J J; Rodenburg, C

    2017-12-01

    Images of Ga + -implanted amorphous silicon layers in a 110 n-type silicon substrate have been collected by a range of detectors in a scanning electron microscope and a helium ion microscope. The effects of the implantation dose and imaging parameters (beam energy, dwell time, etc.) on the image contrast were investigated. We demonstrate a similar relationship for both the helium ion microscope Everhart-Thornley and scanning electron microscope Inlens detectors between the contrast of the images and the Ga + density and imaging parameters. These results also show that dynamic charging effects have a significant impact on the quantification of the helium ion microscope and scanning electron microscope contrast. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  20. 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.

  1. Assessment of Multibeam Backscatter Texture Analysis for Seafloor Sediment Classification

    Science.gov (United States)

    Samsudin, S. A.; Hasan, R. C.

    2017-10-01

    Recently, there have been many debates to analyse backscatter data from multibeam echosounder system (MBES) for seafloor classifications. Among them, two common methods have been used lately for seafloor classification; (1) signal-based classification method which using Angular Range Analysis (ARA) and Image-based texture classification method which based on derived Grey Level Co-occurrence Matrices (GLCMs). Although ARA method could predict sediment types, its low spatial resolution limits its use with high spatial resolution dataset. Texture layers from GLCM on the other hand does not predict sediment types, but its high spatial resolution can be useful for image analysis. The objectives of this study are; (1) to investigate the correlation between MBES derived backscatter mosaic textures with seafloor sediment type derived from ARA method, and (2) to identify which GLCM texture layers have high similarities with sediment classification map derived from signal-based classification method. The study area was located at Tawau, covers an area of 4.7 km2, situated off the channel in the Celebes Sea between Nunukan Island and Sebatik Island, East Malaysia. First, GLCM layers were derived from backscatter mosaic while sediment types (i.e. sediment map with classes) was also constructed using ARA method. Secondly, Principal Component Analysis (PCA) was used determine which GLCM layers contribute most to the variance (i.e. important layers). Finally, K-Means clustering algorithm was applied to the important GLCM layers and the results were compared with classes from ARA. From the results, PCA has identified that GLCM layers of Correlation, Entropy, Contrast and Mean contributed to the 98.77 % of total variance. Among these layers, GLCM Mean showed a good agreement with sediment classes from ARA sediment map. This study has demonstrated different texture layers have different characterisation factors for sediment classification and proper analysis is needed before

  2. Imaging nanometer-scale beamlets arrays of relativistic electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Li, R. K.; To, H.; Musumeci, P. [Department of Physics and Astronomy, UCLA, Los Angeles, California, 90095 (United States)

    2012-12-21

    In this paper we study the evolution of nanometer scale transverse density modulation of a high brightness electron beam through a drift and simple focusing channel. With the help of particle tracking simulations we analyze the effects of space charge forces, emittance and energy spread on the feasibility of recovering an initial nm-scale transverse modulation after transport through a magnifying optical system. These studies are relevant for applications such as time-resolved MeV transmission electron microscopy and in the high brightness electron beam community due to the recent developments of nano-structured cathodes and due to the possibility of taking advantage of nm-structures in the beam for coherent radiation generation.

  3. Image processing for cryogenic transmission electron microscopy of symmetry-mismatched complexes.

    Science.gov (United States)

    Huiskonen, Juha T

    2018-02-08

    Cryogenic transmission electron microscopy (cryo-TEM) is a high-resolution biological imaging method, whereby biological samples, such as purified proteins, macromolecular complexes, viral particles, organelles and cells, are embedded in vitreous ice preserving their native structures. Due to sensitivity of biological materials to the electron beam of the microscope, only relatively low electron doses can be applied during imaging. As a result, the signal arising from the structure of interest is overpowered by noise in the images. To increase the signal-to-noise ratio, different image processing-based strategies that aim at coherent averaging of signal have been devised. In such strategies, images are generally assumed to arise from multiple identical copies of the structure. Prior to averaging, the images must be grouped according to the view of the structure they represent and images representing the same view must be simultaneously aligned relatively to each other. For computational reconstruction of the three-dimensional structure, images must contain different views of the original structure. Structures with multiple symmetry-related substructures are advantageous in averaging approaches because each image provides multiple views of the substructures. However, the symmetry assumption may be valid for only parts of the structure, leading to incoherent averaging of the other parts. Several image processing approaches have been adapted to tackle symmetry-mismatched substructures with increasing success. Such structures are ubiquitous in nature and further computational method development is needed to understanding their biological functions. ©2018 The Author(s).

  4. Trends in the electronic X-ray image formation and processing

    International Nuclear Information System (INIS)

    Meyer-Ebrecht, D.; Spiesberger, W.

    1976-01-01

    A report is given on the technological progress in components for the electronic imaging and reproduction in X-ray diagnostics which could enable the partial replacement of radiophotography. Furthermore, electronic post processing methods, in particular in tomography, are reviewed. (ORU) [de

  5. A new apparatus for electron-ion multiple coincidence momentum imaging spectroscopy

    International Nuclear Information System (INIS)

    Morishita, Y.; Kato, M.; Pruemper, G.; Liu, X.-J.; Lischke, T.; Ueda, K.; Tamenori, Y.; Oura, M.; Yamaoka, H.; Suzuki, I.H.; Saito, N.

    2006-01-01

    We have developed a new experimental apparatus for the electron-ion multiple coincidence momentum imaging spectroscopy in order to obtain the angular distributions of vibration-resolved photoelectrons from molecules fixed in space. The apparatus consists of a four-stage molecular supersonic jet and a spectrometer analyzing three-dimensional momenta of fragment ions and electrons in coincidence

  6. Predicting Electron Population Characteristics in 2-D Using Multispectral Ground-Based Imaging

    Science.gov (United States)

    Grubbs, Guy; Michell, Robert; Samara, Marilia; Hampton, Donald; Jahn, Jorg-Micha

    2018-01-01

    Ground-based imaging and in situ sounding rocket data are compared to electron transport modeling for an active inverted-V type auroral event. The Ground-to-Rocket Electrodynamics-Electrons Correlative Experiment (GREECE) mission successfully launched from Poker Flat, Alaska, on 3 March 2014 at 11:09:50 UT and reached an apogee of approximately 335 km over the aurora. Multiple ground-based electron-multiplying charge-coupled device (EMCCD) imagers were positioned at Venetie, Alaska, and aimed toward magnetic zenith. The imagers observed the intensity of different auroral emission lines (427.8, 557.7, and 844.6 nm) at the magnetic foot point of the rocket payload. Emission line intensity data are correlated with electron characteristics measured by the GREECE onboard electron spectrometer. A modified version of the GLobal airglOW (GLOW) model is used to estimate precipitating electron characteristics based on optical emissions. GLOW predicted the electron population characteristics with 20% error given the observed spectral intensities within 10° of magnetic zenith. Predictions are within 30% of the actual values within 20° of magnetic zenith for inverted-V-type aurora. Therefore, it is argued that this technique can be used, at least in certain types of aurora, such as the inverted-V type presented here, to derive 2-D maps of electron characteristics. These can then be used to further derive 2-D maps of ionospheric parameters as a function of time, based solely on multispectral optical imaging data.

  7. ESTUDIO DEL DESGASTE EROSIVO POR CAVITACIÓN DE UN ACERO AUSTENÍTICO DE ALTO NITRÓGENO APOYADO EN EL USO DE LA DIFRACCIÓN DE ELECTRONES RETROPROYECTADOS-EBSD ASSESSMENT OF CAVITATION-EROSION WEAR OF A HIGH NITROGEN AUSTENITIC STAINLESS STEEL FROM ELECTRON BACKSCATTERING DIFFRACTION-EBSD

    Directory of Open Access Journals (Sweden)

    Dairo Hernán Mesa Grajales

    2010-08-01

    S31803. The samples were characterized by electron backscattering diffraction, EBSD to obtain the crystalline orientation of individual grains. In addition, mass loss measurements were obtained and surface damage evolution was analyzed by scanning electron microscopy (SEM at different times of the test. These results were analyzed as a function of the prior crystallographic characterization. For comparison, a conventional austenitic stainless steel, UNS S30403, was also investigated. It was observed that both the nucleation and the growth of damage are heterogeneous at the grain-size scale due to mesoscale plasticity anisotropy, induced during the CE tests. The heterogeneous character of the cavitation damage is related to both the grain boundary character and the microtexture inside the grains.

  8. Bathymetry and acoustic backscatter: Estero Bay, California

    Science.gov (United States)

    Hartwell, Stephen R.; Finlayson, David P.; Dartnell, Peter; Johnson, Samuel Y.

    2013-01-01

    Between July 30 and August 9, 2012, scientists from the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC), acquired bathymetry and acoustic-backscatter data from Estero Bay, San Luis Obispo, California, under PCMSC Field Activity ID S-05-12-SC. The survey was done using the R/V Parke Snavely outfitted with a multibeam sonar for swath mapping and highly accurate position and orientation equipment for georeferencing. This report provides these data in a number of different formats, as well as a summary of the mapping mission, maps of bathymetry and backscatter, and Federal Geographic Data Committee (FGDC) metadata.

  9. 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 a...

  10. A simple methodology for obtaining X-ray color images in scanning electron microscopy

    International Nuclear Information System (INIS)

    Veiga, M.M. da; Pietroluongo, L.R.V.

    1985-01-01

    A simple methodology for obtaining at least 3 elements X-ray images in only one photography is described. The fluorescent X-ray image is obtained from scanning electron microscopy with energy dispersion analysis system. The change of detector analytic channels, color cellophane foils and color films are used sequentially. (M.C.K.) [pt

  11. Novel low-dose imaging technique for characterizing atomic structures through scanning transmission electron microscope

    Science.gov (United States)

    Su, Chia-Ping; Syu, Wei-Jhe; Hsiao, Chien-Nan; Lai, Ping-Shan; Chen, Chien-Chun

    2017-08-01

    To investigate dislocations or heterostructures across interfaces is now of great interest to condensed matter and materials scientists. With the advances in aberration-corrected electron optics, the scanning transmission electron microscope has demonstrated its excellent capability of characterizing atomic structures within nanomaterials, and well-resolved atomic-resolution images can be obtained through long-exposure data acquisition. However, the sample drifting, carbon contamination, and radiation damage hinder further analysis, such as deriving three-dimensional (3D) structures from a series of images. In this study, a method for obtaining atomic-resolution images with significantly reduced exposure time was developed, using which an original high-resolution image with approximately one tenth the electron dose can be obtained by combining a fast-scan high-magnification image and a slow-scan low-magnification image. The feasibility of obtaining 3D atomic structures using the proposed approach was demonstrated through multislice simulation. Finally, the feasibility and accuracy of image restoration were experimentally verified. This general method cannot only apply to electron microscopy but also benefit to image radiation-sensitive materials using various light sources.

  12. Soft X-ray imaging with axisymmetry microscope and electronic readout

    International Nuclear Information System (INIS)

    Sauneuf, A.; Cavailler, C.; Henry, Ph.; Launspach, J.; Mascureau, J. de; Rostaing, M.

    1984-11-01

    An axisymmetric microscope with 10 X magnification has been constructed; its resolution has been measured using severals grids, backlighted by an X-ray source and found to be near 25 μm. So it could be used to make images of laser driven plasmas in the soft X-ray region. In order to see rapidly those images we have associated it with a new detector. It is a small image converter tube with a soft X-ray photocathode and a P20 phosphor deposited on an optic fiber plate. The electronic image appearing on the screen is read by a CCD working in the spectral range. An electronic image readout chain, which is identical to those we use with streak cameras, then processes automatically and immediatly the images given by the microscope

  13. A Simple Metric for Determining Resolution in Optical, Ion, and Electron Microscope Images.

    Science.gov (United States)

    Curtin, Alexandra E; Skinner, Ryan; Sanders, Aric W

    2015-06-01

    A resolution metric intended for resolution analysis of arbitrary spatially calibrated images is presented. By fitting a simple sigmoidal function to pixel intensities across slices of an image taken perpendicular to light-dark edges, the mean distance over which the light-dark transition occurs can be determined. A fixed multiple of this characteristic distance is then reported as the image resolution. The prefactor is determined by analysis of scanning transmission electron microscope high-angle annular dark field images of Si. This metric has been applied to optical, scanning electron microscope, and helium ion microscope images. This method provides quantitative feedback about image resolution, independent of the tool on which the data were collected. In addition, our analysis provides a nonarbitrary and self-consistent framework that any end user can utilize to evaluate the resolution of multiple microscopes from any vendor using the same metric.

  14. Quantitative methods for the analysis of electron microscope images

    DEFF Research Database (Denmark)

    Skands, Peter Ulrik Vallø

    1996-01-01

    in a number work cases. These mainly falls in the three categories: (i) Description of coarse scale measures to quantify surface structure or texture (topography); (ii) Characterization of fracture surfaces in steels (fractography); (iii) Grain boundary segmentation in sintered ceramics. The theoretical...... 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. Imaging of tissue sections with very slow electrons

    Czech Academy of Sciences Publication Activity Database

    Frank, Luděk; Nebesářová, Jana; Vancová, Marie; Paták, Aleš; Müllerová, Ilona

    2015-01-01

    Roč. 148, JAN 2015 (2015), s. 146-150 ISSN 0304-3991 R&D Projects: GA TA ČR TE01020118; GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 ; RVO:60077344 Keywords : Biological STEM * Ultralow energy STEM * Tissue sections * Cathode lens * Depolymerisation Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.874, year: 2015

  16. Ion and electron beam interaction on surfaces - a detection mechanism for obtaining visual ion beam images

    International Nuclear Information System (INIS)

    Fine, J.; Gorden, R. Jr.

    1978-01-01

    Two-dimensional images have been obtained of ion beam impact cross sections on solid surfaces by the coincident interaction of a rastered electron beam. This detection method is effective in producing images in real time on various insulator surfaces. The size of these images correlates well with ion beam current density profile measurements (at full width) and, therefore, can be very useful for ion beam diagnostics and alignment. (Auth.)

  17. Magnetic Resonance Imaging of Biological Specimens by Electron Paramagnetic Resonance of Nitroxide Spin Labels

    Science.gov (United States)

    Berliner, Lawrence J.; Fujii, Hirotada

    1985-02-01

    Electron paramagnetic resonance imaging was demonstrated on two plant species, Apium graveolens and Coleus blumei. This was accomplished by soaking stems of these plants in the paramagnetic nitroxide imaging agent 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl. The experiments were accomplished at L-band frequency (1.4 to 1.9 gigahertz) with single-turn, flat-loop surface coils. One-dimensional imaging spectra were diagnostic of capillary structure and long-term stability.

  18. Free electron lifetime achievements in Liquid Argon Imaging TPC

    CERN Document Server

    Baibussinov, B; Calligarich, E; Centro, S; Cieslik, K; Farnese, C; Fava, A; Gibin, D; Guglielmi, A; Meng, G; Pietropaolo, F; Rubbia, C; Varanini, F; Ventura, S

    2010-01-01

    A key feature for the success of the Liquid Argon TPC technology is the industrial purification against electro-negative impurities, especially Oxygen and Nitrogen remnants, which have to be initially and continuously kept at an exceptional purity. New purification techniques have been applied to a 120 litres LAr-TPC test facility in the INFN-LNL laboratory. Through-going muon tracks have been used to monitor the LAr purity. The short path length used (30 cm) is compensated by the high accuracy in the observation of the specific ionization of cosmic rays muons at sea level. A free electron lifetime of (21.4+7.3-4.3) ms, namely > 15.8 ms at 90 % C.L. has been observed under stable conditions over several weeks, corresponding to about 15 ppt (part per trillion) of Oxygen equivalent. At 500 V/cm, where the electron speed is approximately of 1.5 mm/us, the free electron lifetime >15 ms corresponds to an attenuation <15 % for a drift path of 5 m, opening the way to reliable operation of LAr TPC for exceptionall...

  19. How well do time-integrated Kα images represent hot electron spatial distributions?

    Science.gov (United States)

    Ovchinnikov, V. M.; Kemp, G. E.; Schumacher, D. W.; Freeman, R. R.; Van Woerkom, L. D.

    2011-07-01

    A computational study is described, which addresses how well spatially resolved time-integrated Kα images recorded in intense laser-plasma experiments correlate with the distribution of "hot" (>1 MeV) electrons as they propagate through the target. The hot electron angular distribution leaving the laser-plasma region is critically important for many applications such as Fast Ignition or laser based x-ray sources; and Kα images are commonly used as a diagnostic. It is found that Kα images can easily mislead due to refluxing and other effects. Using the particle-in-cell code LSP, it is shown that a Kα image is not solely determined by the initial population of forward directed hot electrons, but rather also depends upon "delayed" hot electrons, and in fact continues to evolve long after the end of the laser interaction. Of particular note, there is a population of hot electrons created during the laser-plasma interaction that acquire a velocity direction opposite that of the laser and subsequently reflux off the front surface of the target, deflect when they encounter magnetic fields in the laser-plasma region, and then traverse the target in a wide spatial distribution. These delayed fast electrons create significant features in the Kα time-integrated images. Electrons refluxing from the sides and the back of the target are also found to play a significant role in forming the final Kα image. The relative contribution of these processes is found to vary depending on depth within target. These effects make efforts to find simple correlations between Kα images and, for example, Fast Ignition relevant parameters prone to error. Suggestions for future target design are provided.

  20. New developments in electron microscopy for serial image acquisition of neuronal profiles.

    Science.gov (United States)

    Kubota, Yoshiyuki

    2015-02-01

    Recent developments in electron microscopy largely automate the continuous acquisition of serial electron micrographs (EMGs), previously achieved by laborious manual serial ultrathin sectioning using an ultramicrotome and ultrastructural image capture process with transmission electron microscopy. The new systems cut thin sections and capture serial EMGs automatically, allowing for acquisition of large data sets in a reasonably short time. The new methods are focused ion beam/scanning electron microscopy, ultramicrotome/serial block-face scanning electron microscopy, automated tape-collection ultramicrotome/scanning electron microscopy and transmission electron microscope camera array. In this review, their positive and negative aspects are discussed. © The Author 2015. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Backscattering of light ions from metal surfaces

    International Nuclear Information System (INIS)

    Verbeek, H.

    1975-07-01

    When a metal target is bombarded with light ions some are implanted and some are reflected from the surface or backscattered from deeper layers. This results in an energy distribution of the backscattered particles which reaches from zero to almost the primary energy. The number of the backscattered particles and their energy, angular, and charge distributions depends largely on the energy and the ion target combination. For high energies (i.e., greater than50 keV for protons) particles are backscattered in a single collision governed by the Rutherford cross section. Protons and He-ions with energies of 100 keV to several MeV are widely used for thin film analysis. For lower energies multiple collisions and the screening of the Coulomb potential have to be taken into account, which makes the theoretical treatment more difficult. This energy region is, however, of special interest in the field of nuclear fusion research. Some recent results for energies below 20 keV are discussed in some detail. (auth)

  2. Backscatter nephelometer to calibrate scanning lidar

    Science.gov (United States)

    Cyle E. Wold; Vladmir A. Kovalev; Wei Min Hao

    2008-01-01

    The general concept of an open-path backscatter nephelometer, its design, principles of calibration and the operational use are discussed. The research-grade instrument, which operates at the wavelength 355 nm, will be co-located with a scanning-lidar at measurement sites near wildfires, and used for the lidar calibration. Such a near-end calibration has significant...

  3. Ultra high speed image processing techniques. [electronic packaging techniques

    Science.gov (United States)

    Anthony, T.; Hoeschele, D. F.; Connery, R.; Ehland, J.; Billings, J.

    1981-01-01

    Packaging techniques for ultra high speed image processing were developed. These techniques involve the development of a signal feedthrough technique through LSI/VLSI sapphire substrates. This allows the stacking of LSI/VLSI circuit substrates in a 3 dimensional package with greatly reduced length of interconnecting lines between the LSI/VLSI circuits. The reduced parasitic capacitances results in higher LSI/VLSI computational speeds at significantly reduced power consumption levels.

  4. SEM technique for imaging and measuring electronic transport in nanocomposites based on electric field induced contrast

    Science.gov (United States)

    Jesse, Stephen [Knoxville, TN; Geohegan, David B [Knoxville, TN; Guillorn, Michael [Brooktondale, NY

    2009-02-17

    Methods and apparatus are described for SEM imaging and measuring electronic transport in nanocomposites based on electric field induced contrast. A method includes mounting a sample onto a sample holder, the sample including a sample material; wire bonding leads from the sample holder onto the sample; placing the sample holder in a vacuum chamber of a scanning electron microscope; connecting leads from the sample holder to a power source located outside the vacuum chamber; controlling secondary electron emission from the sample by applying a predetermined voltage to the sample through the leads; and generating an image of the secondary electron emission from the sample. An apparatus includes a sample holder for a scanning electron microscope having an electrical interconnect and leads on top of the sample holder electrically connected to the electrical interconnect; a power source and a controller connected to the electrical interconnect for applying voltage to the sample holder to control the secondary electron emission from a sample mounted on the sample holder; and a computer coupled to a secondary electron detector to generate images of the secondary electron emission from the sample.

  5. X-ray backscatter radiography. Intrusive instead of penetrating, X-ray shadow phenomenon

    International Nuclear Information System (INIS)

    Wrobel, Norma; Kolkoori, Sanjeevareddy; Osterloh, Kurt; European Federation for Non-Destructive Testing

    2013-01-01

    Generally, the primary practical advantage of X-ray backscattering radiography is that there is no need to place a detector on the side of the specimen opposite to the source. Such a situation usually is encountered whenever the specimen is not only standing right in front of a wall or even inside a wall but also if the specimen is such big that radiography is not possible because of the layer thickness to be penetrated. The method used here differs fundamentally from the conventional method to interrogate the object with a scanning beam ('pencil beam') and to collect the whole backscattered radiation from the area. The object is fully illuminated by a (uncollimated) cone beam. Here, the image is recorded with a camera of absorbent material (tungsten, lead), which contains a matrix detector as the image receiver. The optical effect is generated by a special twisted slit collimator which operates according to an extended pinhole camera. The independent positioning of source and camera allows a variable irradiation geometry which causes different images as a result. As a consequence, a complex object in front of a backscattering wall appears completely different than standing alone. So X-ray backscatter images have to be interpreted according to their illumination with X-rays and their surroundings. (orig.)

  6. Designing scheme of a γ-ray ICT system using compton back-scattering

    International Nuclear Information System (INIS)

    Xiao Jianmin

    1998-01-01

    The designing scheme of a γ ray ICT system by using Compton back-scattering is put forward. The technical norms, detector system, γ radioactive source, mechanical scanning equipment, and data acquisition and image reconstruction principle of this ICT are described

  7. Interferometric evidence for the observation of ground backscatter originating behind the CUTLASS coherent HF radars

    Science.gov (United States)

    Milan, S. E.; Jones, T. B.; Robinson, T. R.; Thomas, E. C.; Yeoman, T. K.

    1997-01-01

    Interferometric techniques allow the SuperDARN coherent HF radars to determine the elevation angles of returned backscatter, giving information on the altitude of the scatter volume, in the case of ionospheric backscatter, or the reflection altitude, in the case of ground backscatter. Assumptions have to be made in the determination of elevation angles, including the direction of arrival, or azimuth, of the returned signals, usually taken to be the forward look-direction (north) of the radars, specified by the phasing of the antenna arrays. It is shown that this assumption is not always valid in the case of ground backscatter, and that significant returns can be detected from the backward look-direction of the radars. The response of the interferometer to backscatter from behind the radar is modelled and compared with observations. It is found that ground backscatter from a field-of-view that is the mirror image of the forward-looking field-of-view is a common feature of the observations, and this interpretation successfully explains several anomalies in the received backscatter. Acknowledgements. The authors are grateful to Prof. D. J. Southwood (Imperial College, London), J. C. Samson (University of Alberta, Edmonton), L. J. Lanzerotti (AT&T Bell Laboratories), A. Wolfe (New York City Technical College) and to Dr. M. Vellante (University of LÁquila) for helpful discussions. They also thank Dr. A. Meloni (Istituto Nazionale di Geofisica, Roma) who made available geomagnetic field observations from LÁquila Geomagnetic Observatory. This research activity at LÁquila is supported by MURST (40% and 60% contracts) and by GIFCO/CNR. Topical Editor K.-H. Glaßmeier thanks C. Waters and S. Fujita for their help in evaluating this paper.-> Correspondence to :P. Francia->

  8. Imaging Electron Motion in a Few Layer MoS2 Device

    Science.gov (United States)

    Bhandari, S.; Wang, K.; Watanabe, K.; Taniguchi, T.; Kim, P.; Westervelt, R. M.

    2017-06-01

    Ultrathin sheets of MoS2 are a newly discovered 2D semiconductor that holds great promise for nanoelectronics. Understanding the pattern of current flow will be crucial for developing devices. In this talk, we present images of current flow in MoS2 obtained with a Scanned Probe Microscope (SPM) cooled to 4 K. We previously used this technique to image electron trajectories in GaAs/AlGaAs heterostructures and graphene. The charged SPM tip is held just above the sample surface, creating an image charge inside the device that scatters electrons. By measuring the change in resistance ΔR while the tip is raster scanned above the sample, an image of electron flow is obtained. We present images of electron flow in an MoS2 device patterned into a hall bar geometry. A three-layer MoS2 sheet is encased by two hBN layers, top and bottom, and patterned into a hall-bar with multilayer graphene contacts. An SPM image shows the current flow pattern from the wide contact at the end of the device for a Hall density n = 1.3×1012 cm-2. The SPM tip tends to block flow, increasing the resistance R. The pattern of flow was also imaged for a narrow side contact on the sample. At density n = 5.4×1011 cm-2; the pattern seen in the SPM image is similar to the wide contact. The ability to image electron flow promises to be very useful for the development of ultrathin devices from new 2D materials.

  9. Preliminary backscatter results from the hydrosweep multibeam system

    Digital Repository Service at National Institute of Oceanography (India)

    Hagen, R.A.; Chakraborty, B.; Schenke, H.W.

    of Oceanography to convert the measured electrical energy into acoustic backscatter energy. This conversion includes corrections for the position, slope, and area of the scattering surface. In this paper we present backscatter data from several areas surveyed...

  10. San Francisco Bay Multi-beam Backscatter Imagery: Area A

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Backscatter imagery data were collected over shallow subtidal areas in the San Francisco Bay estuary system. Bathymetric and acoustic backscatter data were collected...

  11. Imaging the potential distribution of individual charged impurities on graphene by low-energy electron holography.

    Science.gov (United States)

    Latychevskaia, Tatiana; Wicki, Flavio; Escher, Conrad; Fink, Hans-Werner

    2017-11-01

    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. Low-energy electrons (30 - 250 eV) are sensitive to localized potential gradients. We employed low-energy electron holography to acquire in-line holograms of individual charged impurities on free-standing graphene. By applying an iterative phase retrieval reconstruction routine we recover the potential distribution of the localized charged impurities present on free-standing graphene. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Assessing the contamination of SuperDARN global convection maps by non-F-region backscatter

    OpenAIRE

    G. Chisham; G. Chisham; M. Pinnock; M. Pinnock

    2002-01-01

    Global convection mapping using line-of-sight Doppler velocity data from the Super Dual Auroral Radar Network (SuperDARN) is now an accepted method of imaging high-latitude ionospheric convection. This mapping process requires that the flow measured by the radars is defined solely by the convection electric field. This is generally only true of radar backscatter from the ionospheric F-region. We investigate the extent to which the E-region and ground backscatter in the SuperDARN data s...

  13. Scanning electron microscope image signal-to-noise ratio monitoring for micro-nanomanipulation.

    Science.gov (United States)

    Marturi, Naresh; Dembélé, Sounkalo; Piat, Nadine

    2014-01-01

    As an imaging system, scanning electron microscope (SEM) performs an important role in autonomous micro-nanomanipulation applications. When it comes to the sub micrometer range and at high scanning speeds, the images produced by the SEM are noisy and need to be evaluated or corrected beforehand. In this article, the quality of images produced by a tungsten gun SEM has been evaluated by quantifying the level of image signal-to-noise ratio (SNR). In order to determine the SNR, an efficient and online monitoring method is developed based on the nonlinear filtering using a single image. Using this method, the quality of images produced by a tungsten gun SEM is monitored at different experimental conditions. The derived results demonstrate the developed method's efficiency in SNR quantification and illustrate the imaging quality evolution in SEM. © 2014 Wiley Periodicals, Inc.

  14. Carbon Nanotube Electron Emitter for X-ray Imaging

    Directory of Open Access Journals (Sweden)

    Jung Su Kang

    2012-11-01

    Full Text Available The carbon nanotube field emitter array was grown on silicon substrate through a resist-assisted patterning (RAP process. The shape of the carbon nanotube array is elliptical with 2.0 × 0.5 mm2 for an isotropic focal spot size at anode target. The field emission properties with triode electrodes show a gate turn-on field of 3 V/µm at an anode emission current of 0.1 mA. The author demonstrated the X-ray source with triode electrode structure utilizing the carbon nanotube emitter, and the transmitted X-ray image was of high resolution.

  15. Cherenkov Ring Imaging Detector front-end electronics

    International Nuclear Information System (INIS)

    Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dasu, S.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.; Marshall, D.; Muller, D.; Nagamine, T.; Oxoby, G.; Ratcliff, B.; Rensing, P.; Schultz, D.; Shapiro, S.; Simopoulos, C.; Solodov, E.; Suekane, F.; Toge, N.; Va'Vra, J.; Williams, S.; Wilson, R.J.; Whitaker, J.S.; Bean, A.; Caldwell, D.; Duboscq, J.; Huber, J.; Lu, A.; Mathys, L.; McHugh, S.; Morrison, R.; Witherell, M.; Yellin, S.; Coyle, P.; Coyne, D.; Spencer, E.; d'Oliveira, A.; Johnson, R.A.; Martinez, J.; Nussbaum, M.; Santha, A.K.S.; Shoup, A.; Stockdale, I.; Jacques, P.; Plano, R.; Stamer, P.; Abe, K.; Hasegawa, K.; Yuta, H.

    1990-10-01

    The SLD Cherenkov Ring Imaging Detector use a proportional wire detector for which a single channel hybrid has been developed. It consists of a preamplifier, gain selectable amplifier, load driver amplifier, power switching, and precision calibrator. For this hybrid, a bipolar, semicustom integrated circuit has been designed which includes video operational amplifiers for two of the gain stages. This approach allows maximization of the detector volume, allows DC coupling, and enables gain selection. System tests show good noise performance, calibration precision, system linearity, and signal shape uniformity over the full dynamic range. 10 refs., 8 figs

  16. User expectations for multibeam echo sounders backscatter strength data-looking back into the future

    Science.gov (United States)

    Lucieer, Vanessa; Roche, Marc; Degrendele, Koen; Malik, Mashkoor; Dolan, Margaret; Lamarche, Geoffroy

    2017-05-01

    With the ability of multibeam echo sounders (MBES) to measure backscatter strength (BS) as a function of true angle of insonification across the seafloor, came a new recognition of the potential of backscatter measurements to remotely characterize the properties of the seafloor. Advances in transducer design, digital electronics, signal processing capabilities, navigation, and graphic display devices, have improved the resolution and particularly the dynamic range available to sonar and processing software manufacturers. Alongside these improvements the expectations of what the data can deliver has also grown. In this paper, we identify these user-expectations and explore how MBES backscatter is utilized by different communities involved in marine seabed research at present, and the aspirations that these communities have for the data in the future. The results presented here are based on a user survey conducted by the GeoHab (Marine Geological and Biological Habitat Mapping) association. This paper summarises the different processing procedures employed to extract useful information from MBES backscatter data and the various intentions for which the user community collect the data. We show how a range of backscatter output products are generated from the different processing procedures, and how these results are taken up by different scientific disciplines, and also identify common constraints in handling MBES BS data. Finally, we outline our expectations for the future of this unique and important data source for seafloor mapping and characterisation.

  17. A Practical and Portable Solids-State Electronic Terahertz Imaging System

    Directory of Open Access Journals (Sweden)

    Ken Smart

    2016-04-01

    Full Text Available A practical compact solid-state terahertz imaging system is presented. Various beam guiding architectures were explored and hardware performance assessed to improve its compactness, robustness, multi-functionality and simplicity of operation. The system performance in terms of image resolution, signal-to-noise ratio, the electronic signal modulation versus optical chopper, is evaluated and discussed. The system can be conveniently switched between transmission and reflection mode according to the application. A range of imaging application scenarios was explored and images of high visual quality were obtained in both transmission and reflection mode.

  18. Imaging properties and energy aberrations of a double-pass cylindrical-mirror electron energy analyzer

    International Nuclear Information System (INIS)

    Erickson, N.E.; Powell, C.J.

    1986-01-01

    The imaging properties and energy aberrations of a commercial double-pass cylindrical-mirror analyzer have been characterized using an extension of the method recently reported by Seah and Mathieu. The electron beam from the coaxial electron gun was rastered across a test surface and the intensity of either elastically scattered electrons or of electrons at other selected energies was stored in a computer as a function of beam position on the specimen and other experimental parameters. The intensity data were later plotted to provide an ''image'' of the detected intensity. Images of this type are presented for electron energies of 100, 500, and 1000 eV and for the application of small offset voltages (typically between -1 and +5 V) between the analyzer and the gun cathode with the instrument operated in conditions appropriate for XPS or AES. Small offset voltages ( or approx. =5 V) lead to image shapes similar to those for the elastic peak but with 20%--40% increased widths. Deflection of the incident beam by up to 2 mm from the axis caused variations of up to +-0.15 eV in the measured positions of the elastic peak. Our observations can be interpreted qualitatively in terms of the known relationship between detected signal and combinations of position of electron emission from the specimen, angle of emission, and electron energy. The images obtained with elastically and inelastically scattered electrons provide a convenient and quantitative means of assessing instrument performance and of defining the specimen area being analyzed for the particular combination of instrument operating conditions and the energy width of AES or XPS features from the specimen

  19. Phase recovery and lensless imaging by iterative methods in optical, X-ray and electron diffraction.

    Science.gov (United States)

    Spence, J C H; Weierstall, U; Howells, M

    2002-05-15

    Thomas Young's quantitative analysis of interference effects provided the confidence needed to revive the wave theory of light, and firmly established the concept of phase in optics. Phase plays a similarly fundamental role in matter-wave interferometry, for which the field-emission electron microscope provides ideal instrumentation. The wave-particle duality is vividly demonstrated by experimental 'Young's fringes' using coherent electron beams under conditions in which the flight time is less than the time between particle emission. A brief historical review is given of electron interferometry and holography, including the Aharonov-Bohm effect and the electron Sagnac interferometer. The simultaneous development of phase-contrast imaging at subnanometre spatial resolution has greatly deepened our understanding of atomic processes in biology, materials science and condensed-matter physics, while electron holography has become a routine tool for the mapping of electrostatic and magnetic fields in materials on a nanometre scale. The encoding of phase information in scattered farfield intensities is discussed, and non-interferometric, non-crystallographic methods for phase retrieval are reviewed in relationship to electron holography. Examples of phase measurement and diffraction-limited imaging using the hybrid input-output iterative algorithm are given, including simulations for soft X-ray imaging, and new experimental results for coherent electron and visible-light scattering. Image reconstruction is demonstrated from experimental electron and visible-light Fraunhofer diffraction patterns. The prospects this provides for lensless imaging using particles for which no lenses exist (such as neutrons, condensates, coherent atom beams and X-rays) are discussed. These new interactions can be expected to provide new information, perhaps, for example, in biology, with the advantage of less damage to samples.

  20. New Insights on Subsurface Imaging of Carbon Nanotubes in Polymer Composites via Scanning Electron Microscopy

    Science.gov (United States)

    Zhao, Minhua; Ming, Bin; Kim, Jae-Woo; Gibbons, Luke J.; Gu, Xiaohong; Nguyen, Tinh; Park, Cheol; Lillehei, Peter T.; Villarrubia, J. S.; Vladar, Andras E.; hide

    2015-01-01

    Despite many studies of subsurface imaging of carbon nanotube (CNT)-polymer composites via scanning electron microscopy (SEM), significant controversy exists concerning the imaging depth and contrast mechanisms. We studied CNT-polyimide composites and, by threedimensional reconstructions of captured stereo-pair images, determined that the maximum SEM imaging depth was typically hundreds of nanometers. The contrast mechanisms were investigated over a broad range of beam accelerating voltages from 0.3 to 30 kV, and ascribed to modulation by embedded CNTs of the effective secondary electron (SE) emission yield at the polymer surface. This modulation of the SE yield is due to non-uniform surface potential distribution resulting from current flows due to leakage and electron beam induced current. The importance of an external electric field on SEM subsurface imaging was also demonstrated. The insights gained from this study can be generally applied to SEM nondestructive subsurface imaging of conducting nanostructures embedded in dielectric matrices such as graphene-polymer composites, silicon-based single electron transistors, high resolution SEM overlay metrology or e-beam lithography, and have significant implications in nanotechnology.

  1. An algorithm to determine backscattering ratio and single scattering albedo

    Digital Repository Service at National Institute of Oceanography (India)

    Suresh, T.; Desa, E.; Matondkar, S.G.P.; Mascarenhas, A.A.M.Q.; Nayak, S.R.; Naik, P.

    and backscattering coefficients and the remote sensing reflectance are used to obtain a relationship for the backscattering ratio, which is defined as the ratio of the total backscattering to the total scattering in terms of the remote sensing reflectance of two...

  2. Ice cloud backscatter study and comparison with CALIPSO and MODIS satellite data.

    Science.gov (United States)

    Ding, Jiachen; Yang, Ping; Holz, Robert E; Platnick, Steven; Meyer, Kerry G; Vaughan, Mark A; Hu, Yongxiang; King, Michael D

    2016-01-11

    An invariant imbedding T-matrix (II-TM) method is used to calculate the single-scattering properties of 8-column aggregate ice crystals. The II-TM based backscatter values are compared with those calculated by the improved geometric-optics method (IGOM) to refine the backscattering properties of the ice cloud radiative model used in the MODIS Collection 6 cloud optical property product. The integrated attenuated backscatter-to-cloud optical depth (IAB-ICOD) relation is derived from simulations using a CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite) lidar simulator based on a Monte Carlo radiative transfer model. By comparing the simulation results and co-located CALIPSO and MODIS (Moderate Resolution Imaging Spectroradiometer) observations, the non-uniform zonal distribution of ice clouds over ocean is characterized in terms of a mixture of smooth and rough ice particles. The percentage of the smooth particles is approximately 6% and 9% for tropical and midlatitude ice clouds, respectively.

  3. Practical implications of backscatter from outside the patient on the dose distribution during total body irradiation

    International Nuclear Information System (INIS)

    Van Dam, J.; Rijnders, A.; Vanuytsel, L.; Zhang, H.-Z.

    1988-01-01

    Total body irradiation (TBI) sometimes requires the set-up of the patient very close to the wall of the treatment room in order to obtain sufficiently large irradiation fields. Under these conditions, backscattered electrons can become clinically important. In the present study, an attempt was made to quantify the dose contribution to the patient from these electrons. Measurements were performed both in experimental conditions and on patients during their TBI treatment. It is concluded that, with the patient close to the wall, backscattered electrons constitute a significant (up to 20% of the dose obtained under electronic equilibrium at the exit port of the beam) radiation dose which can (under certain conditions) influence measurements of exit dose leading to an overestimation of the midline dose and contribute a suuperficial irradiation of the patient without therapeutic benefit. This problem can be solved by interposing a 2 cm thick low-Z absorber between wall and patient. 9 refs.; 5 figs.; 1 table

  4. Investigation of bulk electron densities for dose calculations on cone-beam CT images

    International Nuclear Information System (INIS)

    Lambert, J.; Parker, J.; Gupta, S.; Hatton, J.; Tang, C.; Capp, A.; Denham, J.W.; Wright, P.

    2010-01-01

    Full text: If cone-beam CT images are to be used for dose calculations, then the images must be able to provide accurate electron density information. Twelve patients underwent twice weekly cone-beam CT scans in addition to the planning CT scan. A standardised 5-field treatment plan was applied to 169 of the CBCT images. Doses were calculated using the original electron density values in the CBCT and with bulk electron densities applied. Bone was assigned a density of 288 HU, and all other tissue was assigned to be water equivalent (0 HU). The doses were compared to the dose calculated on the original planning CT image. Using the original HU values in the cone-beam images, the average dose del i vered by the plans from all 12 patients was I. I % lower than the intended 200 cOy delivered on the original CT plans (standard devia tion 0.7%, maximum difference -2.93%). When bulk electron densities were applied to the cone-beam images, the average dose was 0.3% lower than the original CT plans (standard deviation 0.8%, maximum difference -2.22%). Compared to using the original HU values, applying bulk electron densities to the CBCT images improved the dose calculations by almost I %. Some variation due to natural changes in anatomy should be expected. The application of bulk elec tron densities to cone beam CT images has the potential to improve the accuracy of dose calculations due to inaccurate H U values. Acknowledgements This work was partially funded by Cancer Council NSW Grant Number RG 07-06.

  5. Estimation of four-dimensional dose distribution using electronic portal imaging device in radiation therapy

    International Nuclear Information System (INIS)

    Mizoguchi, Asumi; Arimura, Hidetaka; Shioyama, Yoshiyuki

    2013-01-01

    We are developing a method to evaluate four-dimensional radiation dose distribution in a patient body based upon the animated image of EPID (electronic portal imaging device) which is an image of beam-direction at the irradiation. In the first place, we have obtained the image of the dose which is emitted from patient body at therapy planning using therapy planning CT image and dose evaluation algorism. In the second place, we have estimated the emission dose image at the irradiation using EPID animated image which is obtained at the irradiation. In the third place, we have got an affine transformation matrix including respiratory movement in the body by performing linear registration on the emission dose image at therapy planning to get the one at the irradiation. In the fourth place, we have applied the affine transformation matrix on the therapy planning CT image and estimated the CT image 'at irradiation'. Finally we have evaluated four-dimensional dose distribution by calculating dose distribution in the CT image 'at irradiation' which has been estimated for each frame of the EPID animated-image. This scheme may be useful for evaluating therapy results and risk management. (author)

  6. Counterfeit Electronics Detection Using Image Processing and Machine Learning

    International Nuclear Information System (INIS)

    Asadizanjani, Navid; Tehranipoor, Mark; Forte, Domenic

    2017-01-01

    Counterfeiting is an increasing concern for businesses and governments as greater numbers of counterfeit integrated circuits (IC) infiltrate the global market. There is an ongoing effort in experimental and national labs inside the United States to detect and prevent such counterfeits in the most efficient time period. However, there is still a missing piece to automatically detect and properly keep record of detected counterfeit ICs. Here, we introduce a web application database that allows users to share previous examples of counterfeits through an online database and to obtain statistics regarding the prevalence of known defects. We also investigate automated techniques based on image processing and machine learning to detect different physical defects and to determine whether or not an IC is counterfeit. (paper)

  7. Counterfeit Electronics Detection Using Image Processing and Machine Learning

    Science.gov (United States)

    Asadizanjani, Navid; Tehranipoor, Mark; Forte, Domenic

    2017-01-01

    Counterfeiting is an increasing concern for businesses and governments as greater numbers of counterfeit integrated circuits (IC) infiltrate the global market. There is an ongoing effort in experimental and national labs inside the United States to detect and prevent such counterfeits in the most efficient time period. However, there is still a missing piece to automatically detect and properly keep record of detected counterfeit ICs. Here, we introduce a web application database that allows users to share previous examples of counterfeits through an online database and to obtain statistics regarding the prevalence of known defects. We also investigate automated techniques based on image processing and machine learning to detect different physical defects and to determine whether or not an IC is counterfeit.

  8. Sparsity based noise removal from low dose scanning electron microscopy images

    Science.gov (United States)

    Lazar, A.; Fodor, P. S.

    2015-03-01

    Scanning electron microscopes are some of the most versatile tools for imaging materials with nanometer resolution. However, images collected at high scan rates to increase throughput and avoid sample damage, suffer from low signalto- noise ratio (SNR) as a result of the Poisson distributed shot noise associated with the electron production and interaction with the surface imaged. The signal is further degraded by additive white Gaussian noise (AWGN) from the detection electronics. In this work, denoising frameworks are applied to this type of images, taking advantage of their sparsity character, along with a methodology for determining the AWGN. A variance stabilization technique is applied to the raw data followed by a patch-based denoising algorithm. Results are presented both for images with known levels of mixed Poisson-Gaussian noise, and for raw images. The quality of the image reconstruction is assessed based both on the PSNR as well as on measures specific to the application of the data collected. These include accurate identification of objects of interest and structural similarity. High-quality results are recovered from noisy observations collected at short dwell times that avoid sample damage.

  9. Sensitivity of Multi-Source SAR Backscatter to Changes in Forest Aboveground Biomass

    Directory of Open Access Journals (Sweden)

    Wenli Huang

    2015-07-01

    Full Text Available Accurate estimates of forest aboveground biomass (AGB after anthropogenic disturbance could reduce uncertainties in the carbon budget of terrestrial ecosystems and provide critical information to policy makers. Yet, the loss of carbon due to forest disturbance and the gain from post-disturbance recovery have not been sufficiently assessed. In this study, a sensitivity analysis was first conducted to investigate: (1 the influence of incidence angle and soil moisture on Synthetic Aperture Radar (SAR backscatter; (2 the feasibility of cross-image normalization between multi-temporal and multi-sensor SAR data; and (3 the possibility of applying normalized backscatter data to detect forest biomass changes. An empirical model was used to reduce incidence angle effects, followed by cross-image normalization procedure to lessen soil moisture effect. Changes in forest biomass at medium spatial resolution (100 m were mapped using both spaceborne and airborne SAR data. Results indicate that (1 the effect of incidence angle on SAR backscatter could be reduced to less than 1 dB by the correction model for airborne SAR data; (2 over 50% of the changes in SAR backscatter due to soil moisture could be eliminated by the cross-image normalization procedure; and (3 forest biomass changes greater than 100 Mg·ha−1 or above 50% of 150 Mg·ha−1 are detectable using cross-normalized SAR data.

  10. High-frequency attenuation and backscatter measurements of rat blood between 30 and 60 MHz

    International Nuclear Information System (INIS)

    Huang, Chih-Chung

    2010-01-01

    There has recently been a great deal of interest in noninvasive high-frequency ultrasound imaging of small animals such as rats due to their being the preferred animal model for gene therapy and cancer research. Improving the interpretation of the obtained images and furthering the development of the imaging devices require a detailed knowledge of the ultrasound attenuation and backscattering of biological tissue (e.g. blood) at high frequencies. In the present study, the attenuation and backscattering coefficients of the rat red blood cell (RBC) suspensions and whole blood with hematocrits ranging from 6% to 40% were measured between 30 and 60 MHz using a modified substitution approach. The acoustic parameters of porcine blood under the same conditions were also measured in order to compare differences in the blood properties between these two animals. For porcine blood, both whole blood and RBC suspension were stirred at a rotation speed of 200 rpm. Three different rotation speeds of 100, 200 and 300 rpm were carried out for rat blood experiments. The attenuation coefficients of both rat and porcine blood were found to increase linearly with frequency and hematocrit (the values of coefficients of determination (r 2 ) are around 0.82-0.97 for all cases). The average attenuation coefficient of rat whole blood with a hematocrit of 40% increased from 0.26 Nepers mm -1 at 30 MHz to 0.47 Nepers mm -1 at 60 MHz. The maximum backscattering coefficients of both rat and porcine RBC suspensions were between 10% and 15% hematocrits at all frequencies. The fourth-power dependence of backscatter on frequency was approximately valid for rat RBC suspensions with hematocrits between 6% and 40%. However, the frequency dependence of the backscatter estimate deviates from a fourth-power law for porcine RBC suspension with hematocrit higher than 20%. The backscattering coefficient plateaued for hematocrits higher than 15% in porcine blood, but for rat blood it was maximal around a

  11. High-frequency attenuation and backscatter measurements of rat blood between 30 and 60 MHz

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Chih-Chung, E-mail: j648816n@ms23.hinet.ne [Department of Electrical Engineering, Fu Jen Catholic University, Taipei, Taiwan (China)

    2010-10-07

    There has recently been a great deal of interest in noninvasive high-frequency ultrasound imaging of small animals such as rats due to their being the preferred animal model for gene therapy and cancer research. Improving the interpretation of the obtained images and furthering the development of the imaging devices require a detailed knowledge of the ultrasound attenuation and backscattering of biological tissue (e.g. blood) at high frequencies. In the present study, the attenuation and backscattering coefficients of the rat red blood cell (RBC) suspensions and whole blood with hematocrits ranging from 6% to 40% were measured between 30 and 60 MHz using a modified substitution approach. The acoustic parameters of porcine blood under the same conditions were also measured in order to compare differences in the blood properties between these two animals. For porcine blood, both whole blood and RBC suspension were stirred at a rotation speed of 200 rpm. Three different rotation speeds of 100, 200 and 300 rpm were carried out for rat blood experiments. The attenuation coefficients of both rat and porcine blood were found to increase linearly with frequency and hematocrit (the values of coefficients of determination (r{sup 2}) are around 0.82-0.97 for all cases). The average attenuation coefficient of rat whole blood with a hematocrit of 40% increased from 0.26 Nepers mm{sup -1} at 30 MHz to 0.47 Nepers mm{sup -1} at 60 MHz. The maximum backscattering coefficients of both rat and porcine RBC suspensions were between 10% and 15% hematocrits at all frequencies. The fourth-power dependence of backscatter on frequency was approximately valid for rat RBC suspensions with hematocrits between 6% and 40%. However, the frequency dependence of the backscatter estimate deviates from a fourth-power law for porcine RBC suspension with hematocrit higher than 20%. The backscattering coefficient plateaued for hematocrits higher than 15% in porcine blood, but for rat blood it was

  12. Backscattering and negative polarization of agglomerate particles.

    Science.gov (United States)

    Zubko, Evgenij; Shkuratov, Yuriy; Hart, Matthew; Eversole, Jay; Videen, Gorden

    2003-09-01

    We used the discrete dipole approximation to study the backscattering of agglomerate particles consisting of oblong monomers. We varied the aspect ratio of the monomers from approximately 1 (sphere) to 4, while we kept the total particle volume equivalent to that of an x = 10 sphere for m = 1.59 + i0 and 1.50 + i0 and considered two values of agglomerate packing density: rho = 0.25 and rho = 0.1. We found that these particles do not display a prominent brightness opposition effect but do produce significant negative polarization over a range of near-backscattering angles. Increasing the monomers' aspect ratio can make the negative polarization much more prominent. We have noted also that decreasing m and p can reduce the amplitude of the negative polarization for these particles.

  13. Precipitates Segmentation from Scanning Electron Microscope Images through Machine Learning Techniques

    OpenAIRE

    João P. Papa; Clayton R. Pereira; Victor H.C. de Albuquerque; Cleiton C. Silva; Alexandre X. Falcão; João Manuel R. S.Tavares

    2011-01-01

    The presence of precipitates in metallic materials affects its durability, resistance and mechanical properties. Hence, its automatic identification by image processing and machine learning techniques may lead to reliable and efficient assessments on the materials. In this paper, we introduce four widely used supervised pattern recognition techniques to accomplish metallic precipitates segmentation in scanning electron microscope images from dissimilar welding on a Hastelloy C-276 alloy: Supp...

  14. X-Ray Imaging of Ultrafast Magnetic Reconnection Driven by Relativistic Electrons

    Science.gov (United States)

    Raymond, Anthony; McKelvey, Andrew; Zulick, Calvin; Maksimchuk, Anatoly; Thomas, Alexander; Willingale, Louise; Chvykov, Vladimir; Yanovsky, Victor; Krushelnick, Karl

    2014-10-01

    Magnetic reconnection events driven by relativistic electrons are observed between two high intensity laser/plasma interaction sites. The two laser focuses were on average 20 μm FWHM containing 50 TW of power each, delivered with a split f/3 paraboloid onto copper foil targets at a focused intensity of 4×1018 W/cm2. A spherically bent k-alpha X-ray Bragg crystal was utilized to image the interactions, and by motorizing one half of the paraboloid vertically the focal separation was varied between 0-200 μm. While these k-alpha images demonstrated a ring structure surrounding a single focus (due to electrons returning from vacuum to the rear of the target surface), splitting the focuses revealed the rings of either spot interacting and enhancing between the focuses, evidencing magnetic reconnection driven by the relativistic electron currents. Imaging the transversely propagating electrons with a filtered LANEX screen demonstrated relativistic currents with spatial nonuniformities potentially directly originating from reconnection events, and varying target geometries were used to investigate the resulting effects on the spatial electron profiles. At present PIC simulations are being conducted to better understand and attempt to reproduce the measured electron outflow dynamics. Currently at: ELI Attosecond Light Pulse Source.

  15. Backscatter Correction Algorithm for TBI Treatment Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Nieto, B.; Sanchez-Doblado, F.; Arrans, R.; Terron, J.A. [Dpto. Fisiología Médica y Biofísica, Universidad de Sevilla, Avda. Sánchez Pizjuán, 4. E-41009, Sevilla (Spain); Errazquin, L. [Servicio Oncología Radioterápica, Hospital Univ.V. Macarena. Dr. Fedriani, s/n. E-41009, Sevilla (Spain)

    2015-01-15

    The accuracy requirements in target dose delivery is, according to ICRU, ±5%. This is so not only in standard radiotherapy but also in total body irradiation (TBI). Physical dosimetry plays an important role in achieving this recommended level. The semi-infinite phantoms, customarily used for dosimetry purposes, give scatter conditions different to those of the finite thickness of the patient. So dose calculated in patient’s points close to beam exit surface may be overestimated. It is then necessary to quantify the backscatter factor in order to decrease the uncertainty in this dose calculation. The backward scatter has been well studied at standard distances. The present work intends to evaluate the backscatter phenomenon under our particular TBI treatment conditions. As a consequence of this study, a semi-empirical expression has been derived to calculate (within 0.3% uncertainty) the backscatter factor. This factor depends lineally on the depth and exponentially on the underlying tissue. Differences found in the qualitative behavior with respect to standard distances are due to scatter in the bunker wall close to the measurement point.

  16. Submolecular Electronic Mapping of Single Cysteine Molecules by in Situ Scanning Tunneling Imaging

    DEFF Research Database (Denmark)

    Zhang, Jingdong; Chi, Qijin; Nazmutdinov, R. R.

    2009-01-01

    based on a slab model for the metal surface. The ordered monolayer offers a platform for submolecular scale electronic mapping that is an issue of fundamental interest but remains a challenge in STM imaging science and surface chemistry. Single Cys molecules were mapped as three electronic subunits...... bulk. The correlation between physical location and electronic contrast of the adsorbed molecules was also revealed by the computational data. The present study shows that cysteine packing in the adlayer on Au(110) from the liquid environment is in contrast to that from the ultrahigh-vacuum environment...

  17. Optimization of Monochromated TEM for Ultimate Resolution Imaging and Ultrahigh Resolution Electron Energy Loss Spectroscopy

    KAUST Repository

    Lopatin, Sergei

    2017-09-01

    The performance of a monochromated transmission electron microscope with Wien type monochromator is optimized to achieve an extremely narrow energy spread of electron beam and an ultrahigh energy resolution with spectroscopy. The energy spread in the beam is improved by almost an order of magnitude as compared to specified values. The optimization involves both the monochromator and the electron energy loss detection system. We demonstrate boosted capability of optimized systems with respect to ultra-low loss EELS and sub-angstrom resolution imaging (in a combination with spherical aberration correction).

  18. Time-resolved imaging of purely valence-electron dynamics during a chemical reaction

    DEFF Research Database (Denmark)

    Hockett, Paul; Bisgaard, Christer Z.; Clarkin, Owen J.

    2011-01-01

    Chemical reactions are manifestations of the dynamics of molecular valence electrons and their couplings to atomic motions. Emerging methods in attosecond science can probe purely electronic dynamics in atomic and molecular systems(1-6). By contrast, time-resolved structural-dynamics methods......,17): in both cases, this sensitivity derives from the ionization-matrix element(18,19). Here we demonstrate a time-resolved molecular-frame photoelectron-angular-distribution (TRMFPAD) method for imaging the purely valence-electron dynamics during a chemical reaction. Specifically, the TRMFPADs measured during...

  19. Comparing Fourier optics and contrast transfer function modeling of image formation in low energy electron microscopy.

    Science.gov (United States)

    Yu, K M; Locatelli, A; Altman, M S

    2017-12-01

    A theoretical understanding of image formation in cathode lens microscopy can facilitate image interpretation. We compare Fourier Optics (FO) and Contrast Transfer Function (CTF) approaches that were recently adapted from other realms of microscopy to model image formation in low energy electron microscopy (LEEM). Although these two approaches incorporate imaging errors from several sources similarly, they differ in the way that the image intensity is calculated. The simplification that is used in the CTF calculation advantageously leads to its computational efficiency. However, we find that lens aberrations, and spatial and temporal coherence may affect the validity of the CTF approach to model LEEM image formation under certain conditions. In particular, these effects depend strongly on the nature of the object being imaged and also become more pronounced with increasing defocus. While the use of the CTF approach appears to be justified for objects that are routinely imaged with LEEM, comparison of theory to experimental observations of a focal image series for rippled, suspended graphene reveals one example where FO works, but CTF does not. This work alerts us to potential pitfalls and guides the effective use of FO and CTF approaches. It also lays the foundation for quantitative image evaluation using these methods. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Deblurring of class-averaged images in single-particle electron microscopy

    International Nuclear Information System (INIS)

    Park, Wooram; Chirikjian, Gregory S; Madden, Dean R; Rockmore, Daniel N

    2010-01-01

    This paper proposes a method for the deblurring of class-averaged images in single-particle electron microscopy (EM). Since EM images of biological samples are very noisy, the images which are nominally identical projection images are often grouped, aligned and averaged in order to cancel or reduce the background noise. However, the noise in the individual EM images generates errors in the alignment process, which creates an inherent limit on the accuracy of the resulting class averages. This inaccurate class average due to the alignment errors can be viewed as the result of a convolution of an underlying clear image with a blurring function. In this work, we develop a deconvolution method that gives an estimate for the underlying clear image from a blurred class-averaged image using precomputed statistics of misalignment. Since this convolution is over the group of rigid-body motions of the plane, SE(2), we use the Fourier transform for SE(2) in order to convert the convolution into a matrix multiplication in the corresponding Fourier space. For practical implementation we use a Hermite-function-based image modeling technique, because Hermite expansions enable lossless Cartesian-polar coordinate conversion using the Laguerre–Fourier expansions, and Hermite expansion and Laguerre–Fourier expansion retain their structures under the Fourier transform. Based on these mathematical properties, we can obtain the deconvolution of the blurred class average using simple matrix multiplication. Tests of the proposed deconvolution method using synthetic and experimental EM images confirm the performance of our method

  1. Olympic Coast National Marine Sanctuary - mos110_0204b.tif - Multibeam backscatter mosaic from survey area 110_0204b

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A multibeam backscatter image (0-35 m water depths) mosaiced from hydrographic data collected during a August/September 2003seafloor survey. A Reson 8101 multibeam...

  2. Olympic Coast National Marine Sanctuary - mos110_0204c.tif - Multibeam backscatter mosaic from survey area 110_0204c

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A multibeam backscatter image (0-35 m water depths) mosaiced from hydrographic data collected during a August/September 2003seafloor survey. A Reson 8101 multibeam...

  3. Olympic Coast National Marine Sanctuary - mos110_0204a.tif - Multibeam backscatter mosaic from survey area 110_0204a

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A multibeam backscatter image (0-35 m water depths) mosaiced from hydrographic data collected during a July/August 2002seafloor survey. A Reson 8101 multibeam...

  4. NOAA ESRI Geotiff - NOAA ESRI Geotiff - 3 m Backscatter Mosaic of Mona Island, Puerto Rico, Project NF-08-04, UTM 19N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 3 meter resolution backscatter mosaic of selected portions of seafloor around Mona Island, Puerto Rico. NOAA's NOS/NCCOS/CCMA Biogeography...

  5. NOS TIFF Unified 3M Backscatter Mosaic, La Parguera, Puerto Rico and St. Croix 2006: of US Virgin Islands, 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 and southwest shore (La Parguera) of Puerto Rico....

  6. NOAA ESRI Grid - NOAA ESRI GRID - 3 m Backscatter Mosaic of Tourmaline Bank, Puerto Rico, Project NF-08-04, UTM 19N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 3 meter resolution backscatter mosaic of selected portions of seafloor around Tourmaline Bank, Puerto Rico. NOAA's NOS/NCCOS/CCMA...

  7. NOAA TIFF Graphic - 0.5 meter Backscatter Mosaic of St. John, U.S. Virgin Islands, 2004 (NCEI Accession 0131850)

    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...

  8. NOAA TIFF Graphic- 0.5m Backscatter Mosaic of St. Croix (Buck Island), US Virgin Islands, 2005 (NCEI Accession 0131860)

    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 Team...

  9. NOAA ESRI Grid - NOAA ESRI GRID - 3 m Backscatter Mosaic of Mona Island, Puerto Rico, Project NF-08-04, UTM 19N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This image represents a 3 meter resolution backscatter mosaic of selected portions of seafloor around Mona Island, Puerto Rico. NOAA's NOS/NCCOS/CCMA Biogeography...

  10. Testing and Comparison of Imaging Detectors for Electrons in the Energy Range 10-20 keV

    Science.gov (United States)

    Matheson, J.; Moldovan, G.; Kirkland, A.; Allinson, N.; Abrahams, J. P.

    2017-11-01

    Interest in direct detectors for low-energy electrons has increased markedly in recent years. Detection of electrons in the energy range up to low tens of keV is important in techniques such as photoelectron emission microscopy (PEEM) and electron backscatter diffraction (EBSD) on scanning electron microscopes (SEMs). The PEEM technique is used both in the laboratory and on synchrotron light sources worldwide. The ubiquity of SEMs means that there is a very large market for EBSD detectors for materials studies. Currently, the most widely used detectors in these applications are based on indirect detection of incident electrons. Examples include scintillators or microchannel plates (MCPs), coupled to CCD cameras. Such approaches result in blurring in scintillators/phosphors, distortions in optical systems, and inefficiencies due the limited active area of MCPs. In principle, these difficulties can be overcome using direct detection in a semiconductor device. Growing out of a feasibility study into the use of a direct detector for use on an XPEEM, we have built at Rutherford Appleton Laboratory a system to illuminate detectors with an electron beam of energy up to 20 keV . We describe this system in detail. It has been used to measure the performance of a custom back-thinned monolithic active pixel sensor (MAPS), a detector based on the Medipix2 chip, and a commercial detector based on MCPs. We present a selection of the results from these measurements and compare and contrast different detector types.

  11. Testing an inversion method for estimating electron energy fluxes from all-sky camera images

    Directory of Open Access Journals (Sweden)

    N. Partamies

    2004-06-01

    Full Text Available An inversion method for reconstructing the precipitating electron energy flux from a set of multi-wavelength digital all-sky camera (ASC images has recently been developed by tomografia. Preliminary tests suggested that the inversion is able to reconstruct the position and energy characteristics of the aurora with reasonable accuracy. This study carries out a thorough testing of the method and a few improvements for its emission physics equations.

    We compared the precipitating electron energy fluxes as estimated by the inversion method to the energy flux data recorded by the Defense Meteorological Satellite Program (DMSP satellites during four passes over auroral structures. When the aurorae appear very close to the local zenith, the fluxes inverted from the blue (427.8nm filtered ASC images or blue and green line (557.7nm images together give the best agreement with the measured flux values. The fluxes inverted from green line images alone are clearly larger than the measured ones. Closer to the horizon the quality of the inversion results from blue images deteriorate to the level of the ones from green images. In addition to the satellite data, the precipitating electron energy fluxes were estimated from the electron density measurements by the EISCAT Svalbard Radar (ESR. These energy flux values were compared to the ones of the inversion method applied to over 100 ASC images recorded at the nearby ASC station in Longyearbyen. The energy fluxes deduced from these two types of data are in general of the same order of magnitude. In 35% of all of the blue and green image inversions the relative errors were less than 50% and in 90% of the blue and green image inversions less than 100%.

    This kind of systematic testing of the inversion method is the first step toward using all-sky camera images in the way in which global UV images have recently been used to estimate the energy fluxes. The

  12. Testing an inversion method for estimating electron energy fluxes from all-sky camera images

    Directory of Open Access Journals (Sweden)

    N. Partamies

    2004-06-01

    Full Text Available An inversion method for reconstructing the precipitating electron energy flux from a set of multi-wavelength digital all-sky camera (ASC images has recently been developed by tomografia. Preliminary tests suggested that the inversion is able to reconstruct the position and energy characteristics of the aurora with reasonable accuracy. This study carries out a thorough testing of the method and a few improvements for its emission physics equations. We compared the precipitating electron energy fluxes as estimated by the inversion method to the energy flux data recorded by the Defense Meteorological Satellite Program (DMSP satellites during four passes over auroral structures. When the aurorae appear very close to the local zenith, the fluxes inverted from the blue (427.8nm filtered ASC images or blue and green line (557.7nm images together give the best agreement with the measured flux values. The fluxes inverted from green line images alone are clearly larger than the measured ones. Closer to the horizon the quality of the inversion results from blue images deteriorate to the level of the ones from green images. In addition to the satellite data, the precipitating electron energy fluxes were estimated from the electron density measurements by the EISCAT Svalbard Radar (ESR. These energy flux values were compared to the ones of the inversion method applied to over 100 ASC images recorded at the nearby ASC station in Longyearbyen. The energy fluxes deduced from these two types of data are in general of the same order of magnitude. In 35% of all of the blue and green image inversions the relative errors were less than 50% and in 90% of the blue and green image inversions less than 100%. This kind of systematic testing of the inversion method is the first step toward using all-sky camera images in the way in which global UV images have recently been used to estimate the energy fluxes. The advantages of ASCs, compared to the space-born imagers, are

  13. Dynamics of annular bright field imaging in scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Findlay, S.D.; Shibata, N.; Sawada, H.; Okunishi, E.; Kondo, Y.; Ikuhara, Y.

    2010-01-01

    We explore the dynamics of image formation in the so-called annular bright field mode in scanning transmission electron microscopy, whereby an annular detector is used with detector collection range lying within the cone of illumination, i.e. the bright field region. We show that this imaging mode allows us to reliably image both light and heavy columns over a range of thickness and defocus values, and we explain the contrast mechanisms involved. The role of probe and detector aperture sizes is considered, as is the sensitivity of the method to intercolumn spacing and local disorder.

  14. PENGARUH ELECTRONIC WORD OF MOUTH (eWOM TWITTER @batikair TERHADAP BRAND IMAGE

    Directory of Open Access Journals (Sweden)

    Cherry Kartika

    2015-05-01

    Full Text Available This study aims to determine the influence of the Electronic Word of Mouth twitter @batikair in terms of the following dimensions are intensity dimension to the brand image, valence of opinion dimension to the brand image, and content dimension to the brand image.The sampling technique in this study using purposive sampling technique with criteria from Batik Air passengers in period of June 2015. The data in this study are primary data that collected through questionnaires. Data were analyzed using multiple regression analysis with the classical assumptions.Based on the results of data analysis and discussion, it can be concluded as follows: (1 There is eWOM twitter @batikair influence in terms of intensity dimension to the brand image. (2 There is a eWOM twitter @batikair influence in terms of valence of opinion dimension to the brand image. @batikair. (3 There is a positive eWOM twitter @batikair influence in terms of content dimension to the brand image, it means that the better available information from social network sites relating to products and services will be a positive influence on @batikairbrand image enhancement.   Penelitian ini bertujuan untuk mengetahui pengaruh Electronic Word of Mouth (eWOM twitter @batikair ditinjau dari dimensi-dimensi berikut yaitu dimensi intensity terhadap brand image, dimensi valence of opinion terhadap brand image, dan dimensi content terhadap brand image.Teknik pengambilan sampel pada penelitian ini menggunakan teknik purposive sampling dengan kriteria tertentu yaitu para penumpang Batik Air. Data pada penelitian ini adalah data primer yang dikumpulkan melalui kuesioner. Teknik analisis data menggunakan analisis regresi berganda dengan asumsi klasik.Berdasarkan pada hasil analisis data dan pembahasan maka dapat disimpulkan sebagai berikut: (1 Terdapat pengaruh eWOM twitter @batikair ditinjau dari dimensi intensity terhadap brand imag.e. (2 Terdapat pengaruh eWOM twitter @batikair ditinjau dari dimensi

  15. Reducing charging effects in scanning electron microscope images by Rayleigh contrast stretching method (RCS).

    Science.gov (United States)

    Wan Ismail, W Z; Sim, K S; Tso, C P; Ting, H Y

    2011-01-01

    To reduce undesirable charging effects in scanning electron microscope images, Rayleigh contrast stretching is developed and employed. First, re-scaling is performed on the input image histograms with Rayleigh algorithm. Then, contrast stretching or contrast adjustment is implemented to improve the images while reducing the contrast charging artifacts. This technique has been compared to some existing histogram equalization (HE) extension techniques: recursive sub-image HE, contrast stretching dynamic HE, multipeak HE and recursive mean separate HE. Other post processing methods, such as wavelet approach, spatial filtering, and exponential contrast stretching, are compared as well. Overall, the proposed method produces better image compensation in reducing charging artifacts. Copyright © 2011 Wiley Periodicals, Inc.

  16. An introduction to sample preparation and imaging by cryo-electron microscopy for structural biology

    Science.gov (United States)

    Thompson, Rebecca F.; Walker, Matt; Siebert, C. Alistair; Muench, Stephen P.; Ranson, Neil A.

    2016-01-01

    Transmission electron microscopy (EM) is a versatile technique that can be used to image biological specimens ranging from intact eukaryotic cells to individual proteins >150 kDa. There are several strategies for preparing samples for imaging by EM, including negative staining and cryogenic freezing. In the last few years, cryo-EM has undergone a ‘resolution revolution’, owing to both advances in imaging hardware, image processing software, and improvements in sample preparation, leading to growing number of researchers using cryo-EM as a research tool. However, cryo-EM is still a rapidly growing field, with unique challenges. Here, we summarise considerations for imaging of a range of specimens from macromolecular complexes to cells using EM. PMID:26931652

  17. Correlation of live-cell imaging with volume scanning electron microscopy.

    Science.gov (United States)

    Lucas, Miriam S; Günthert, Maja; Bittermann, Anne Greet; de Marco, Alex; Wepf, Roger

    2017-01-01

    Live-cell imaging is one of the most widely applied methods in live science. Here we describe two setups for live-cell imaging, which can easily be combined with volume SEM for correlative studies. The first procedure applies cell culture dishes with a gridded glass support, which can be used for any light microscopy modality. The second approach is a flow-chamber setup based on Ibidi μ-slides. Both live-cell imaging strategies can be followed up with serial blockface- or focused ion beam-scanning electron microscopy. Two types of resin embedding after heavy metal staining and dehydration are presented making best use of the particular advantages of each imaging modality: classical en-bloc embedding and thin-layer plastification. The latter can be used only for focused ion beam-scanning electron microscopy, but is advantageous for studying cell-interactions with specific substrates, or when the substrate cannot be removed. En-bloc embedding has diverse applications and can be applied for both described volume scanning electron microscopy techniques. Finally, strategies for relocating the cell of interest are discussed for both embedding approaches and in respect to the applied light and scanning electron microscopy methods. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. The stability of liquid-filled matrix ionization chamber electronic portal imaging devices for dosimetry purposes

    NARCIS (Netherlands)

    Louwe, R. J. W.; Tielenburg, R.; van Ingen, K. M.; Mijnheer, B. J.; van Herk, M. B.

    2004-01-01

    This study was performed to determine the stability of liquid-filled matrix ionization chamber (LiFi-type) electronic portal imaging devices (EPID) for dosimetric purposes. The short- and long-term stability of the response was investigated, as well as the importance of factors influencing the

  19. 77 FR 11588 - Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof

    Science.gov (United States)

    2012-02-27

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-831] Certain Electronic Devices for Capturing and Transmitting Images, and Components Thereof AGENCY: U.S. International Trade Commission... Trade Commission on January 10, 2012, under section 337 of the Tariff Act of 1930, as amended, 19 U.S.C...

  20. 75 FR 39971 - In the Matter of Certain Electronic Imaging Devices; Notice of Investigation

    Science.gov (United States)

    2010-07-13

    ... INTERNATIONAL TRADE COMMISSION [Inv. No. 337-TA-726] In the Matter of Certain Electronic Imaging Devices; Notice of Investigation AGENCY: U.S. International Trade Commission. ACTION: Institution of....S. International Trade Commission on May 13, 2010, under section 337 of the Tariff Act of 1930, as...