WorldWideScience

Sample records for monochromatic cathodoluminescence imaging

  1. Cathodoluminescence Imaging Using Nanodiamond Color Centers

    Science.gov (United States)

    Glenn, David; Zhang, Huiliang; Kasthuri, Narayanan; Trifonov, Alexei; Schalek, Richard; Lichtman, Jeff; Walsworth, Ronald

    2011-05-01

    We demonstrate a nanoscale imaging technique based on cathodoluminescence (CL) emitted by color centers in nanodiamonds (NDs) under excitation by an electron beam in a scanning electron microscope (SEM). We have identified several classes of color centers that are spectrally distinct at room temperature and can be obtained with high reliability in NDs with diameters on the order of 50 nm or smaller. Compared to standard CL markers, ND color centers are bright and highly stable under SEM excitation. In conjunction with appropriate functionalization of the ND surfaces, ND-CL will provide nanoscale information about molecular function to augment the structural information obtained with standard SEM techniques. We discuss an exciting application of this approach to neuroscience, specifically in the generation of high-resolution maps of the connections between neurons (``Connectomics'').

  2. Angle-resolved cathodoluminescence imaging polarimetry

    CERN Document Server

    Osorio, Clara I; Brenny, Benjamin; Polman, Albert; Koenderink, A Femius

    2015-01-01

    Cathodoluminescence spectroscopy (CL) allows characterizing light emission in bulk and nanostructured materials and is a key tool in fields ranging from materials science to nanophotonics. Previously, CL measurements focused on the spectral content and angular distribution of emission, while the polarization was not fully determined. Here we demonstrate a technique to access the full polarization state of the cathodoluminescence emission, that is the Stokes parameters as a function of the emission angle. Using this technique, we measure the emission of metallic bullseye nanostructures and show that the handedness of the structure as well as nanoscale changes in excitation position induce large changes in polarization ellipticity and helicity. Furthermore, by exploiting the ability of polarimetry to distinguish polarized from unpolarized light, we quantify the contributions of different types of coherent and incoherent radiation to the emission of a gold surface, silicon and gallium arsenide bulk semiconductor...

  3. Cement stratigraphy: Image probes of cathodoluminescent facies.

    OpenAIRE

    Vuillemin, Aurèle; Ndiaye, Mapathe; Martini, Rossana; Davaud, Eric Jean

    2011-01-01

    Cement stratigraphy of carbonates aims to establish the chronology of processes involved in the rock diagenesis. Regional cement stratigraphy allows correlations and understanding of the petrological heterogeneities in reservoirs and aquifers, but is a long and rigorous approach. This article exposes a methodology of image analysis that facilitates the spatial correlation of diagenetic events in carbonate rocks. Based on the statistical comparison of signals extracted from the red spectrum em...

  4. Reconstruction of quasi-monochromatic images from a multiple monochromatic x-ray imaging diagnostic for inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Izumi, N; Turner, R; Barbee, T; Koch, J; Welser, L; Mansini, R

    2004-04-15

    We have developed a software package for image reconstruction of a multiple monochromatic x-ray imaging diagnostics (MMI) for diagnostic of inertial conferment fusion capsules. The MMI consists of a pinhole array, a multi-layer Bragg mirror, and a charge injection device image detector (CID). The pinhole array projects {approx}500 sub-images onto the CID after reflection off the multi-layer Bragg mirror. The obtained raw images have continuum spectral dispersion on its vertical axis. For systematic analysis, a computer-aided reconstruction of the quasi-monochromatic image is essential.

  5. Detailed Study of Defects in Silicon Solar Cells by Cathodoluminescence Spectrum Imaging: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Romero, M. J.; Ostapenko, S.; Al-Jassim, M. M.; Tarasov, I.; Sheldon, P.

    2003-08-01

    We have recently developed a spectrum imaging system for cathodoluminescence (CLsi) at NREL, which has been successfully applied to different semiconductors. The advanced multi-channel detection required for CLsi consists of an ultrafast spectrum acquisition triggered by the electron beam during scanning. Spectra are acquired either with a Roper Scientific silicon EEV-1340400 cryogenic CCD or an InGaAs 5121 cryogenic PDA, depending on the range of spectral emission. Acquisition times by pixel are typically of 10 to 20 ms (180 seconds for a 100100 pixel image). The output of spectrum imaging measurements is thus represented by a series of emission spectra. CCDIMAG, the software developed for CLsi, processes this spectrum series to reconstruct monochromatic images or extract the spectrum from any area on the image. This system is operated on the JEOL-5800 scanning electron microscope (SEM). CLsi measurements can be performed at temperatures between 15 K and 300 K. A low-vibration ARS Displex DE-202 closed-circuit cryostat provides cryogenic operation. The interface for vibration isolation has been developed to be compatible with SEM observation.

  6. Atlas of monochromatic images of planetary nebulae

    CERN Document Server

    Weidmann, W A; Valdarenas, R R Vena; Ahumada, J A; Volpe, M G; Mudrik, A

    2016-01-01

    We present an atlas of more than one hundred original images of planetary nebulae (PNe). These images were taken in a narrow-band filter centred on the nebular emission of the [N II] during several observing campaigns using two moderate-aperture telescopes, at the Complejo Astron\\'omico El Leoncito (CASLEO), and the Estaci\\'on Astrof\\'isica de Bosque Alegre (EABA), both in Argentina. The data provided by this atlas represent one of the most extensive image surveys of PNe in [N II]. We compare the new images with those available in the literature, and briefly describe all cases in which our [N II] images reveal new and interesting structures.

  7. Broadband, monochromatic and quasi-monochromatic x-ray propagation in multi-Z media for imaging and diagnostics

    Science.gov (United States)

    Westphal, Maximillian S.; Lim, Sara N.; Nahar, Sultana N.; Chowdhury, Enam; Pradhan, Anil K.

    2017-08-01

    With the advent of monochromatic and quasi-monochromatic x-ray sources, we explore their potential with computational and experimental studies on propagation through a combination of low and high-Z (atomic number) media for applications to imaging and detection. The multi-purpose code GEANT4 and a new code PHOTX are employed in numerical simulations, and a variety of x-ray sources are considered: conventional broadband devices with well-known spectra, quasi-monochromatic laser driven sources, and monochromatic synchrotron x-rays. Phantom samples consisting of layers of low-Z and high-Z material are utilized, with atomic-molecular species ranging from H2O to gold. Differential and total attenuation of x-ray fluxes from the different x-ray sources are illustrated through simulated x-ray images. Main conclusions of this study are: I. It is shown that a 65 keV Gaussian quasi-monochromatic source is capable of better contrast with less radiation exposure than a common 120 kV broadband simulator. II. A quantitative measure is defined and computed as a metric to compare the efficacy of any two x-ray sources, as a function of concentration of high-Z moieties in predominantly low-Z environment and depth of penetration. III. Characteristic spectral features of \

  8. Fusion of colour and monochromatic images with edge emphasis

    Directory of Open Access Journals (Sweden)

    Rade M. Pavlović

    2014-02-01

    Full Text Available We propose a novel method to fuse true colour images with monochromatic non-visible range images that seeks to encode important structural information from monochromatic images efficiently but also preserve the natural appearance of the available true chromacity information. We utilise the β colour opponency channel of the lαβ colour as the domain to fuse information from the monochromatic input into the colour input by the way of robust grayscale fusion. This is followed by an effective gradient structure visualisation step that enhances the visibility of monochromatic information in the final colour fused image. Images fused using this method preserve their natural appearance and chromacity better than conventional methods while at the same time clearly encode structural information from the monochormatic input. This is demonstrated on a number of well-known true colour fusion examples and confirmed by the results of subjective trials on the data from several colour fusion scenarios. Introduction The goal of image fusion can be broadly defined as: the representation of visual information contained in a number of input images into a single fused image without distortion or loss of information. In practice, however, a representation of all available information from multiple inputs in a single image is almost impossible and fusion is generally a data reduction task.  One of the sensors usually provides a true colour image that by definition has all of its data dimensions already populated by the spatial and chromatic information. Fusing such images with information from monochromatic inputs in a conventional manner can severely affect natural appearance of the fused image. This is a difficult problem and partly the reason why colour fusion received only a fraction of the attention than better behaved grayscale fusion even long after colour sensors became widespread. Fusion method Humans tend to see colours as contrasts between opponent

  9. Contrast imaging with a monochromatic x-ray scanner

    Science.gov (United States)

    Pole, Donald J.; Popovic, Kosta; Williams, Mark B.

    2008-03-01

    We are currently developing a monochromatic x-ray source for small animal tomographic imaging. This source consists of a conventional cone beam microfocus x-ray tube with a tungsten target coupled to a filter that uses Bragg diffraction to transmit only x-rays within a narrow energy range (~3 keV FWHM). A tissue-equivalent mouse phantom was used to a) evaluate how clearly CT imaging using the quasi-monoenergetic beam is able to differentiate tissue types compared to conventional polyenergetic CT, and b) to test the ability of the source and Bragg filter combination to perform dual energy, iodine contrast enhanced imaging. Single slice CT scans of the phantom were obtained both with polyenergetic (1.8 mm Al filtration) and quasi-monoenergetic beams. Region of interest analysis showed that pixel value variance was signifcantly reduced in the quasi-monochromatic case compared to the polyenergetic case, suggesting a reduction in the variance of the linear attenuation coefficients of the tissue equivalent materials due to the narrower energy spectrum. To test dual energy iodine K-edge imaging, vials containing solutions with a range of iodine contrasts were added to the phantom. Single-slice CT scans were obtained using spectra with maximum values at 30 and 35 keV, respectively. Analysis of the resulting difference images (35 keV image - 30 keV image) shows that the magnitude of the difference signal produced by iodine exceeds that of bone for iodine concentrations above ~20 mg/ml, and that of muscle and fat tissues for iodine concentrations above ~5 mg/ml.

  10. Cathodoluminescence : an imaging technique for the search of extraterrestrial life

    Science.gov (United States)

    Ramboz, C.; Rubert, Y.; Bost, N.; Westall, F.; Lerouge, C.

    2012-04-01

    Solids irradiated by a 10-20 keV electron beam emit ligth in the UV-visible range, which is called cathodoluminescence (CL). CL imagery is a powerful tool for visualizing minerals and their internal structures (lattice defects, zoning). For example, terrestrial calcite, either of sedimentary or biogenic origin, often display a bright orange CL, as a result of the incorporation of trace Mn2+ in its lattice. Aragonite can also be discriminated from calcite by its green CL. Carbonates are a major target for the search of life on Mars, and CL imagery could contribute to reveal carbonates in situ. Thomas et al. [1] have validated the concept of an electron lamp to make CL imagery of a rock surface placed in a martian CO2 atmosphere. We present 2 examples of terrestrial bacterial microstructures that are revealed by CL. (1) In Sinemurian sediments from the Montmiral borehole (Valence Basin, France), banded wavy calcite in contact with pyrite represents fossilized biofilms of sulfato-reducing bacteria, as confirmed by the sulfur isotopic composition of pyrite ~+36 %0 PDB. (2) At l'Ile Crémieux, north of the Valence basin, a dense filamentous microbial/fungal community with a bright orange CL signature is embedded in vuggy calcite from a tectonic vein. The mat is anchored 1-2 mm deep in the oolitic veinwall and emerges at right angle in the 'open' fracture space. Finally, carbonate vesicles and exhalite crusts from the Svalbard basalt in Groendland, with orange CL, are shown as analogues to carbonates from the martian ALH84001 igneous meteorite. [1]Thomas et al. (2009) in A. Gucsik (Ed.) "Cathodoluminescence and Its Application in the Planetary Sciences"

  11. Syn- and postkinematic cement textures in fractured carbonate rocks: Insights from advanced cathodoluminescence imaging

    Science.gov (United States)

    Ukar, Estibalitz; Laubach, Stephen E.

    2016-10-01

    In calcite and dolomite deposits in fractures, transmitted light and optical cathodoluminescence methods detect crack-seal texture in some fractures, but scanning electron microscope-based cathodoluminescence (SEM-CL) combined with secondary-electron images and element maps, reveals crack-seal and cement growth textures where previous SEM-CL imaging methods found massive or featureless deposits. In a range of fractured carbonate rocks, patterns and textures of calcite and dolomite cements precipitated during and after fracture growth resemble complex accumulation patterns found in quartz in sandstone fractures, suggesting that some apparent differences between carbonate mineral and quartz deposits in fractures reflect the limits of previous imaging methods. Advances in delineating textures in widespread carbonate mineral deposits in fractures provide evidence for growth and occlusion of fracture porosity.

  12. Monochromatic X-ray propagation in multi-Z media for imaging and diagnostics including Kα Resonance Fluorescence

    Science.gov (United States)

    Westphal, Maximillian; Lim, Sara; Nahar, Sultana; Pradhan, Anil

    2016-05-01

    Aimed at monochromatic X-ray imaging and therapy, broadband, monochromatic, and quasi-monochromatic X-ray sources and propagation through low and high-Z (HZ) media were studied with numerically and experimentally. Monte Carlo simulations were performed using the software package Geant4, and a new code Photx, to simulate X-ray image contrast, depth of penetration, and total attenuation. The data show that monochromatic and quasi-monochromatic X-rays achieve improved contrast at lower absorbed radiation doses compared to conventional broadband 120 kV or CT scans. Experimental quasi-monochromatic high-intensity laser-produced plasma sources and monochromatic synchrotron beam data are compared. Physical processes responsible for X-ray photoexcitation and absorption are numerically modelled, including a novel mechanism for accelerating Kα resonance fluorescence via twin monochromatic X-ray beam. Potential applications are medical diagnostics and high-Z material detection. Acknowledgement: Ohio Supercomputer Center, Columbus, OH.

  13. The monochromatic imaging mode of a RITA-type neutron spectrometer

    DEFF Research Database (Denmark)

    Bahl, C.R.H.; Andersen, P.; Klausen, S.N.;

    2004-01-01

    The imaging monochromatic mode of a neutron spectrometer with a multi-bladed RITA analyser system is so far unexplored. We present analytical calculations that define the mode. It is shown that the mode can be realised for PG (002) analyser crystals, from incident energies of about 3.2 meV and up......, allowing the important cases of 3.7, 5.0 and 13.7 meV. Due to beam divergence, the neutron rays from neighbouring analyser blades are found to overlap slightly. Hence, the optimal use of the monochromatic imaging mode would be found by employing an adjustable radial collimator to limit the spread...

  14. The role of transition radiation in cathodoluminescence imaging and spectroscopy of thin-foils

    Energy Technology Data Exchange (ETDEWEB)

    Mendis, B.G. [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Howkins, A. [Experimental Techniques Centre, Brunel University, Uxbridge UB8 3PH (United Kingdom); Stowe, D. [Gatan UK, 25 Nuffield Way, Abingdon, Oxfordshire OX14 1RL (United Kingdom); Major, J.D.; Durose, K. [Stephenson Institute for Renewable Energy, University of Liverpool, Liverpool L69 7ZF (United Kingdom)

    2016-08-15

    There is renewed interest in cathodoluminescence (CL) in the transmission electron microscope, since it can be combined with low energy loss spectroscopy measurements and can also be used to probe defects, such as grain boundaries and dislocations, at high spatial resolution. Transition radiation (TR), which is emitted when the incident electron crosses the vacuum-specimen interface, is however an important artefact that has received very little attention. The importance of TR is demonstrated on a wedge shaped CdTe specimen of varying thickness. For small specimen thicknesses (<250 nm) grain boundaries are not visible in the panchromatic CL image. Grain boundary contrast is produced by electron–hole recombination within the foil, and a large fraction of that light is lost to multiple-beam interference, so that thicker specimens are required before the grain boundary signal is above the TR background. This is undesirable for high spatial resolution. Furthermore, the CL spectrum contains additional features due to TR which are not part of the ‘bulk’ specimen. Strategies to minimise the effects of TR are also discussed. - Highlights: • Grain boundary cathodoluminescence contrast is anomalously low in the TEM. • This is due to transition radiation (TR) generated at the vacuum-specimen interface. • Thick foils are required for the recombination luminescence to suppress TR. • This is undesirable for high spatial resolution analysis of grain boundaries. • Strategies to minimise TR are also discussed.

  15. Excitation and Imaging of Resonant Optical Modes of Au Triangular Nano-Antennas Using Cathodoluminescence Spectroscopy

    CERN Document Server

    Kumar, Anil; Mabon, James C; Chow, Edmond; Fang, Nicholas X

    2010-01-01

    Cathodoluminescence (CL) imaging spectroscopy is an important technique to understand resonant behavior of optical nanoantennas. We report high-resolution CL spectroscopy of triangular gold nanoantennas designed with near-vacuum effective index and very small metal-substrate interface. This design helped in addressing issues related to background luminescence and shifting of dipole modes beyond visible spectrum. Spatial and spectral investigations of various plasmonic modes are reported. Out-of-plane dipole modes excited with vertically illuminated electron beam showed high-contrast tip illumination in panchromatic imaging. By tilting the nanostructures during fabrication, in-plane dipole modes of antennas were excited. Finite-difference time-domain simulations for electron and optical excitations of different modes showed excellent agreement with experimental results. Our approach of efficiently exciting antenna modes by using low index substrates is confirmed both with experiments and numerical simulations....

  16. Scanning electron microscope cathodoluminescence imaging of subgrain boundaries, twins and planar deformation features in quartz

    Science.gov (United States)

    Hamers, M. F.; Pennock, G. M.; Drury, M. R.

    2016-11-01

    The study of deformation features has been of great importance to determine deformation mechanisms in quartz. Relevant microstructures in both growth and deformation processes include dislocations, subgrains, subgrain boundaries, Brazil and Dauphiné twins and planar deformation features (PDFs). Dislocations and twin boundaries are most commonly imaged using a transmission electron microscope (TEM), because these cannot directly be observed using light microscopy, in contrast to PDFs. Here, we show that red-filtered cathodoluminescence imaging in a scanning electron microscope (SEM) is a useful method to visualise subgrain boundaries, Brazil and Dauphiné twin boundaries. Because standard petrographic thin sections can be studied in the SEM, the observed structures can be directly and easily correlated to light microscopy studies. In contrast to TEM preparation methods, SEM techniques are non-destructive to the area of interest on a petrographic thin section.

  17. Automated sub-5 nm image registration in integrated correlative fluorescence and electron microscopy using cathodoluminescence pointers

    Science.gov (United States)

    Haring, Martijn T.; Liv, Nalan; Zonnevylle, A. Christiaan; Narvaez, Angela C.; Voortman, Lenard M.; Kruit, Pieter; Hoogenboom, Jacob P.

    2017-03-01

    In the biological sciences, data from fluorescence and electron microscopy is correlated to allow fluorescence biomolecule identification within the cellular ultrastructure and/or ultrastructural analysis following live-cell imaging. High-accuracy (sub-100 nm) image overlay requires the addition of fiducial markers, which makes overlay accuracy dependent on the number of fiducials present in the region of interest. Here, we report an automated method for light-electron image overlay at high accuracy, i.e. below 5 nm. Our method relies on direct visualization of the electron beam position in the fluorescence detection channel using cathodoluminescence pointers. We show that image overlay using cathodoluminescence pointers corrects for image distortions, is independent of user interpretation, and does not require fiducials, allowing image correlation with molecular precision anywhere on a sample.

  18. Automated sub-5 nm image registration in integrated correlative fluorescence and electron microscopy using cathodoluminescence pointers

    Science.gov (United States)

    Haring, Martijn T.; Liv, Nalan; Zonnevylle, A. Christiaan; Narvaez, Angela C.; Voortman, Lenard M.; Kruit, Pieter; Hoogenboom, Jacob P.

    2017-01-01

    In the biological sciences, data from fluorescence and electron microscopy is correlated to allow fluorescence biomolecule identification within the cellular ultrastructure and/or ultrastructural analysis following live-cell imaging. High-accuracy (sub-100 nm) image overlay requires the addition of fiducial markers, which makes overlay accuracy dependent on the number of fiducials present in the region of interest. Here, we report an automated method for light-electron image overlay at high accuracy, i.e. below 5 nm. Our method relies on direct visualization of the electron beam position in the fluorescence detection channel using cathodoluminescence pointers. We show that image overlay using cathodoluminescence pointers corrects for image distortions, is independent of user interpretation, and does not require fiducials, allowing image correlation with molecular precision anywhere on a sample. PMID:28252673

  19. Monochromatic imaging instrumentation for applications in aeronomy of the earth and planets

    Science.gov (United States)

    Baumgardner, Jeffrey; Flynn, Brian; Mendillo, Michael

    1992-01-01

    Monochromatic imaging instrumentation has been developed that uses narrow-band (12 A FWHP) interference filters or plane reflection gratings for 2D imaging and imaging spectrograph applications. By changing the optics in front of the filter or grating, the field of view of the instruments can be varied from 180 deg to 6 deg. In the case of the 2D monochromatic imager, the 12 mm-diameter filtered image is formed at about f/1 on the input photocathode of an intensified CCD camera (380 x 488 pixels). The sensitivities of the systems are about 50-100 R s (S/N about 2). Examples of data taken with both of these instruments include detection and mapping of Jupiter's sodium magnetonebula and stable auroral red arcs in the terrestrial ionosphere.

  20. Spectrum-per-Pixel Cathodoluminescence Imaging of CdTe Thin-Film Bevels

    Energy Technology Data Exchange (ETDEWEB)

    Moseley, John; Al-Jassim, Mowafak M.; Burst, James; Guthrey, Harvey L.; Metzger, Wyatt K.

    2016-11-21

    We conduct T=6 K cathodoluminescence (CL) spectrum imaging with a nano-scale electron beam on beveled surfaces of CdTe thin-films at different critical stages of standard CdTe device fabrication. The through-thickness total CL intensity profiles are consistent with a reduction in grain boundary recombination due to the CdCl2 treatment. Color-coded maps of the low-temperature luminescence transition energies reveal that CdTe thin films have remarkably non-uniform opto-electronic properties, which depend strongly on sample processing history. The grain-to-grain S content in the interdiffused CdTe/CdS region is estimated from a sample size of thirty-five grains, and the S content in adjacent grains varies significantly in CdCl2-treated samples. A low-temperature luminescence model is developed to interpret spectral behavior at grain boundaries and grain interiors.

  1. Imaging the Hidden Modes of Ultrathin Plasmonic Strip Antennas by Cathodoluminescence

    KAUST Repository

    Barnard, Edward S.

    2011-10-12

    We perform spectrally resolved cathodoluminescence (CL) imaging nanoscopy using a 30 keV electron beam to identify the resonant modes of an ultrathin (20 nm), laterally tapered plasmonic Ag nanostrip antenna. We resolve with deep-subwavelength resolution four antenna resonances (resonance orders m = 2-5) that are ascribed to surface plasmon polariton standing waves that are confined on the strip. We map the local density of states on the strip surface and show that it has contributions from symmetric and antisymmetric surface plasmon polariton modes, each with a very different mode index. This work illustrates the power of CL experiments that can visualize hidden modes that for symmetry reasons have been elusive in optical light scattering experiments. © 2011 American Chemical Society.

  2. Single-image measurements of monochromatic subdiffraction dimolecular separations

    CERN Document Server

    DeCenzo, Shawn H; Wang, Y M

    2010-01-01

    Measuring subdiffraction separations between single fluorescent particles is important for biological, nano-, and medical-technology studies. Major challenges include (i) measuring changing molecular separations with high temporal resolution while (ii) using identical fluorescent labels. Here we report a method that measures subdiffraction separations between two identical fluorophores by using a single image of milliseconds exposure time and a standard single-molecule fluorescent imaging setup. The fluorophores do not need to be bleached and the separations can be measured down to 40 nm with nanometer precision. The method is called single-molecule image deconvolution -- SMID, and in this article it measures the standard deviation (SD) of Gaussian-approximated combined fluorescent intensity profiles of the two subdiffraction-separated fluorophores. This study enables measurements of (i) subdiffraction dimolecular separations using a single image, lifting the temporal resolution of seconds to milliseconds, wh...

  3. Dual energy CT: How well can pseudo-monochromatic imaging reduce metal artifacts?

    Energy Technology Data Exchange (ETDEWEB)

    Kuchenbecker, Stefan, E-mail: stefan.kuchenbecker@dkfz.de; Faby, Sebastian; Sawall, Stefan; Kachelrieß, Marc [German Cancer Research Center (DKFZ), Heidelberg 69120 (Germany); Lell, Michael [Friedrich-Alexander-University (FAU), Erlangen 91054 (Germany)

    2015-02-15

    Purpose: Dual Energy CT (DECT) provides so-called monoenergetic images based on a linear combination of the original polychromatic images. At certain patient-specific energy levels, corresponding to certain patient- and slice-dependent linear combination weights, e.g., E = 160 keV corresponds to α = 1.57, a significant reduction of metal artifacts may be observed. The authors aimed at analyzing the method for its artifact reduction capabilities to identify its limitations. The results are compared with raw data-based processing. Methods: Clinical DECT uses a simplified version of monochromatic imaging by linearly combining the low and the high kV images and by assigning an energy to that linear combination. Those pseudo-monochromatic images can be used by radiologists to obtain images with reduced metal artifacts. The authors analyzed the underlying physics and carried out a series expansion of the polychromatic attenuation equations. The resulting nonlinear terms are responsible for the artifacts, but they are not linearly related between the low and the high kV scan: A linear combination of both images cannot eliminate the nonlinearities, it can only reduce their impact. Scattered radiation yields additional noncanceling nonlinearities. This method is compared to raw data-based artifact correction methods. To quantify the artifact reduction potential of pseudo-monochromatic images, they simulated the FORBILD abdomen phantom with metal implants, and they assessed patient data sets of a clinical dual source CT system (100, 140 kV Sn) containing artifacts induced by a highly concentrated contrast agent bolus and by metal. In each case, they manually selected an optimal α and compared it to a raw data-based material decomposition in case of simulation, to raw data-based material decomposition of inconsistent rays in case of the patient data set containing contrast agent, and to the frequency split normalized metal artifact reduction in case of the metal

  4. Correlative cathodoluminescence and near-infrared fluorescence imaging for bridging from nanometer to millimeter scale bioimaging.

    Science.gov (United States)

    Niioka, H; Fukushima, S; Ichimiya, M; Ashida, M; Miyake, J; Araki, T; Hashimoto, M

    2014-11-01

    Correlative light and electron microscopy (CLEM) is one attractive method of observing biological specimens because it combines the advantages of both light microscopy (LM) and electron microscopy (EM). In LM, specimens are fully hydrated, and molecular species are distinguished based on the fluorescence colors of probes. EM provides both high-spatial-resolution images superior to those obtained with LM and ultrastructural information of cellular components. The combination of LM and EM gives much more information than either method alone, which helps us to analyze cellular function in more detail.We propose a Y2O3:Tm,Yb phosphor nanoparticle which allows upconversion luminescence (UCL) imaging with near-infrared (NIR) light excitation and cathodoluminescence (CL) imaging [1], where the light emission induced by an electron beam is called cathodoluminescence (CL). Due to electron beam excitation, the spatial resolution of CL microscopy is on the order of nanometers [2,3]. Upconversion is a process in which lower energy, longer wavelength excitation light is transduced to higher energy, shorter wavelength emission light. So far, in LM observation for CLEM, ultraviolet (UV) or visible light has been used for excitation. However, UV and visible light have limited ability to observe deep tissue regions due to absorption, scattering, and autofluorescence. On the other hand, NIR light does not suffer from these problems. Rare-earth-doped upconversion nanophosphors have been applied to biological imaging because of the advantages of NIR excitation [4].We investigated the UCL and CL spectra of Y2O3:Tm,Yb nanophosphors. Y2O3:Tm,Yb nanophosphors that emit visible and near-infrared UCL under 980nm irradiation and blue CL via electron beam excitation. To confirm bimodality of our nanophosphors, correlative UCL/CL images of the nanophosphors were obtained for the same region. The nanophosphors were poured onto a P doped Si substrate (Fig. 1(a)) and were irradiated with 980 nm

  5. Cathodoluminescence spectrum imaging analysis of CdTe thin-film bevels

    Energy Technology Data Exchange (ETDEWEB)

    Moseley, John [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA; Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA; Al-Jassim, Mowafak M. [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA; Guthrey, Harvey L. [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA; Burst, James M. [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA; Duenow, Joel N. [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA; Ahrenkiel, Richard K. [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA; Colorado School of Mines, 1500 Illinois Street, Golden, Colorado 80401, USA; Metzger, Wyatt K. [National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, USA

    2016-09-09

    We conducted T = 6 K cathodoluminescence (CL) spectrum imaging with a nanoscale electron beam on beveled surfaces of CdTe thin films at the critical stages of standard CdTe solar cell fabrication. We find that the through-thickness CL total intensity profiles are consistent with a reduction in grain-boundary recombination due to the CdCl2 treatment. The color-coded CL maps of the near-band-edge transitions indicate significant variations in the defect recombination activity at the micron and sub-micron scales within grains, from grain to grain, throughout the film depth, and between films with different processing histories. We estimated the grain-interior sulfur-alloying fraction in the interdiffused CdTe/CdS region of the CdCl2-treated films from a sample of 35 grains and found that it is not strongly correlated with CL intensity. A kinetic rate-equation model was used to simulate grain-boundary (GB) and grain-interior CL spectra. Simulations indicate that the large reduction in the exciton band intensity and relatively small decrease in the lower-energy band intensity at CdTe GBs or dislocations can be explained by an enhanced electron-hole non-radiative recombination rate at the deep GB or dislocation defects. Simulations also show that higher GB concentrations of donors and/or acceptors can increase the lower-energy band intensity, while slightly decreasing the exciton band intensity.

  6. Cathodoluminescence spectrum imaging analysis of CdTe thin-film bevels

    Science.gov (United States)

    Moseley, John; Al-Jassim, Mowafak M.; Guthrey, Harvey L.; Burst, James M.; Duenow, Joel N.; Ahrenkiel, Richard K.; Metzger, Wyatt K.

    2016-09-01

    We conducted T = 6 K cathodoluminescence (CL) spectrum imaging with a nanoscale electron beam on beveled surfaces of CdTe thin films at the critical stages of standard CdTe solar cell fabrication. We find that the through-thickness CL total intensity profiles are consistent with a reduction in grain-boundary recombination due to the CdCl2 treatment. The color-coded CL maps of the near-band-edge transitions indicate significant variations in the defect recombination activity at the micron and sub-micron scales within grains, from grain to grain, throughout the film depth, and between films with different processing histories. We estimated the grain-interior sulfur-alloying fraction in the interdiffused CdTe/CdS region of the CdCl2-treated films from a sample of 35 grains and found that it is not strongly correlated with CL intensity. A kinetic rate-equation model was used to simulate grain-boundary (GB) and grain-interior CL spectra. Simulations indicate that the large reduction in the exciton band intensity and relatively small decrease in the lower-energy band intensity at CdTe GBs or dislocations can be explained by an enhanced electron-hole non-radiative recombination rate at the deep GB or dislocation defects. Simulations also show that higher GB concentrations of donors and/or acceptors can increase the lower-energy band intensity, while slightly decreasing the exciton band intensity.

  7. Frequency-locked pulse sequencer for high-frame-rate monochromatic tissue motion imaging.

    Science.gov (United States)

    Azar, Reza Zahiri; Baghani, Ali; Salcudean, Septimiu E; Rohling, Robert

    2011-04-01

    To overcome the inherent low frame rate of conventional ultrasound, we have previously presented a system that can be implemented on conventional ultrasound scanners for high-frame-rate imaging of monochromatic tissue motion. The system employs a sector subdivision technique in the sequencer to increase the acquisition rate. To eliminate the delays introduced during data acquisition, a motion phase correction algorithm has also been introduced to create in-phase displacement images. Previous experimental results from tissue- mimicking phantoms showed that the system can achieve effective frame rates of up to a few kilohertz on conventional ultrasound systems. In this short communication, we present a new pulse sequencing strategy that facilitates high-frame-rate imaging of monochromatic motion such that the acquired echo signals are inherently in-phase. The sequencer uses the knowledge of the excitation frequency to synchronize the acquisition of the entire imaging plane to that of an external exciter. This sequencing approach eliminates any need for synchronization or phase correction and has applications in tissue elastography, which we demonstrate with tissue-mimicking phantoms.

  8. Solar monochromatic images in magneto-sensitive spectral lines and maps of vector magnetic fields

    Science.gov (United States)

    Shihui, Y.; Jiehai, J.; Minhan, J.

    1985-01-01

    A new method which allows by use of the monochromatic images in some magneto-sensitive spectra line to derive both the magnetic field strength as well as the angle between magnetic field lines and line of sight for various places in solar active regions is described. In this way two dimensional maps of vector magnetic fields may be constructed. This method was applied to some observational material and reasonable results were obtained. In addition, a project for constructing the three dimensional maps of vector magnetic fields was worked out.

  9. A monochromatic x-ray imaging system for characterizing low-density foams

    Energy Technology Data Exchange (ETDEWEB)

    Lanier, Nicholas E. [Los Alamos National Laboratory; Taccetti, Jose M. [Los Alamos National Laboratory; Hamilton, Christopher E. [Los Alamos National Laboratory

    2012-05-04

    In High Energy Density (HED) laser experiments, targets often require small, low-density, foam components. However, their limited size can preclude single component characterization, forcing one to rely solely on less accurate bulk measurements. We have developed a monochromatic imaging a system to characterize both the density and uniformity of single component low-mass foams. This x-ray assembly is capable of determining line-averaged density variations near the 1% level, and provides statistically identical results to those obtained at the Brookhaven's NSLS. This system has the added benefit of providing two-dimensional density data, allowing an assessment of density uniformity.

  10. Quantitative investigation of felsic rock textures using cathodoluminescence images and other techniques

    Science.gov (United States)

    Higgins, Michael Denis

    2017-04-01

    The qualitative and quantitative study of the textures (microstructures) of felsic rocks has been somewhat neglected, as compared to mafic rocks. This is partly because the major phases are all colourless with similar birefringence. This problem has been addressed using cold-cathode cathodoluminescence (CL). This microscope-based method easily distinguishes quartz, K-feldspar and plagioclase, and can also identify zoning and other structures. A combination of CL and cross-polarised light images can be used to trace the outlines of most crystals in a thin section. These techniques have been applied to a dacite and three granitoids in order to understand the process of solidification. In three of the rocks, macrocrysts or oikocrysts have sealed-in textures whilst the rock was partially solid. These data are used to construct diagrams illustrating possible paths of phase abundance, crystal sizes and temperature during solidification. In all four rocks, the saturation order appears to be amphibole ± biotite + apatite:plagioclase:K-feldspar:quartz. Plagioclase initially crystallises in a regime of increasing undercooling to give a kinetic texture. It is generally coarsened after K-feldspar has saturated. K-feldspar saturated and then immediately started to coarsen in three of the rocks. Competition between the growth of orthoclase and plagioclase may determine if macrocrysts or oikocrysts are formed. Quartz is the last phase to saturate and was coarsened in some rocks. The overall rock texture is therefore controlled by a combination of compositional effects on saturation temperatures, such as volatile content and cooling path. The solidification paths determined here are not unique, but do show what can be achieved from a textural study, with no knowledge of the volatile content of the magma.

  11. Silicon-Vacancy Color Centers in Nanodiamonds: Cathodoluminescence Imaging Marker in the Near Infrared

    OpenAIRE

    Zhang, Huiliang; Aharonovich, Igor; Glenn, David R.; Schalek, R.; Magyar, Andrew P.; Lichtman, Jeff W.; Hu, Evelyn L.; Walsworth, Ronald L.

    2013-01-01

    We demonstrate that nanodiamonds fabricated to incorporate silicon-vacancy (Si-V) color centers provide bright, spectrally narrow, and stable cathodoluminescence (CL) in the near-infrared. Si-V color centers containing nanodiamonds are promising as non-bleaching optical markers for correlated CL and secondary electron microscopy, including applications to nanoscale bioimaging.

  12. X-ray Absorption Imaging of High-Intensity Discharge Lamps Using Monochromatic Synchrotron Radiation

    Science.gov (United States)

    Curry, John J.; Sansonetti, Craig J.; Hechtfischer, Ulrich; Adler, Helmar G.

    2002-10-01

    We will report results from the imaging of Hg vapor in high-intensity discharge lamps using synchrotron radiation and digital detectors. These measurements extend previous work on x-ray absorption imaging in arc lamps using an x-ray tube and a passive phosphor image plate detector^i. The large x-ray flux obtained from the Advanced Photon Source (Argonne National Laboratory) combined with the electronic gating capabilities of an intensified charge-coupled device detector have allowed us to obtain time-resolved Hg distributions with high spatial resolution. Monochromatic synchrotron radiation improves the accuracy over what can be obtained with quasi-continuum radiation from an x-ray tube source. ^iJ. J. Curry, M. Sakai, and J. E. Lawler, Journal of Applied Physics 84, 3066 (1998).

  13. SU-E-I-40: Phantom Research On Monochromatic Images Taken by Dual CBCT with Multiple Energy Sets

    Energy Technology Data Exchange (ETDEWEB)

    Gao, R [Duke University, Durham, NC - North Carolina (United States); Shandong University, Jinan, Shandong (China); Wang, H [Shandong University, Jinan, Shandong (China); Zhang, Y [Duke University, Durham, NC - North Carolina (United States); Mao, R [The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan (China); Ren, L; Yin, F [Duke University Medical Center, Durham, NC (United States)

    2015-06-15

    Purpose: To evaluate the quality of monochromatic images at the same virtual monochromatic energy using dual cone-beam computed tomography (CBCT) with either kV/kV or MV/kV or MV/MV energy sets. Methods: CT images of Catphan 504 phantom were acquired using four different KV and MV settings: 80kV, 140kV, 4MV, 6MV. Three sets of monochromatic images were calculated: 80kV-140kV, 140kV-4MV and 4MV-6MV. Each set of CBCT images were reconstructed from the same selected virtual monochromatic energy of 1MeV. Contrast-to-Noise Ratios (CNRs) were calculated and compared between each pair of images with different energy sets. Results: Between kV/MV and MV/MV images, the CNRs are comparable for all inserts. However, differences of CNRs were observed between the kV/kV and kV/MV images. Delrin’s CNR ratio between kV/kV image and kV/MV image is 1.634. LDPE’s (Low-Density Polyethylene) CNR ratio between kV/kV and kV/MV images is 0.509. Polystyrene’s CNR ratio between kV/kV image and kV/MV image is 2.219. Conclusion: Preliminary results indicated that the CNRs calculated from CBCT images reconstructed from either kV/MV projections or MV/MV projections for the same selected virtual monochromatic energy may be comparable.

  14. Virtual monochromatic imaging in dual-source and dual-energy CT for visualization of acute ischemic stroke

    CERN Document Server

    Hara, Hidetake; Matsuzawa, Hiroki; Inoue, Toshiyuki; Abe, Shinji; Satoh, Hitoshi; Nakajima, Yasuo

    2015-01-01

    We have recently developed a phantom that simulates acute ischemic stroke. We attempted to visualize acute-stage cerebral infarction by applying virtual monochromatic images to this phantom using dual-energy CT (DECT). Virtual monochromatic images were created using DECT from 40 to 100 keV at every 10 keV and from 60 to 80 keV at every 1 keV, under three energy conditions of tube voltages with thin (Sn) filters. Calculation of the CNR values allowed us to evaluate the visualization of acute-stage cerebral infarction. The CNR value of a virtual monochromatic image was the highest at 68 keV under 80 kV / Sn 140 kV, at 72 keV under 100 kV / Sn 140 kV, and at 67 keV under 140 kV / 80 kV. The CNR values of virtual monochromatic images between 65 and 75 keV were significantly higher than those obtained for all other created energy images. Therefore, optimal conditions for visualizing acute ischemic stroke were achievable.

  15. Virtual monochromatic imaging in dual-source and dual-energy CT for visualization of acute ischemic stroke

    Science.gov (United States)

    Hara, Hidetake; Muraishi, Hiroshi; Matsuzawa, Hiroki; Inoue, Toshiyuki; Nakajima, Yasuo; Satoh, Hitoshi; Abe, Shinji

    2015-07-01

    We have recently developed a phantom that simulates acute ischemic stroke. We attempted to visualize an acute-stage cerebral infarction by using dual-energy Computed tomography (DECT) to obtain virtual monochromatic images of this phantom. Virtual monochromatic images were created by using DECT voltages from 40 to 100 keV in steps of 10 keV and from 60 to 80 keV in steps of 1 keV, under three conditions of the tube voltage with thin (Sn) filters. Calculation of the CNR values allowed us to evaluate the visualization of acute-stage cerebral infarction. The CNR value of a virtual monochromatic image was the highest at 68 keV under 80 kV / Sn 140 kV, at 72 keV under 100 kV / Sn 140 kV, and at 67 keV under 140 kV / 80 kV. The CNR values of virtual monochromatic images at voltages between 65 and 75 keV were significantly higher than those obtained for all other created images. Therefore, the optimal conditions for visualizing acute ischemic stroke were achievable.

  16. Metal artifacts reduction using monochromatic images from spectral CT: Evaluation of pedicle screws in patients with scoliosis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yang, E-mail: wangzhang227@163.com [Department of Radiology, The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008 (China); Qian, Bangping, E-mail: qianbangping@163.com [Spine Service, Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008 (China); Li, Baoxin, E-mail: wangzhi68@163.com [Department of Radiology, The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008 (China); Qin, Guochu, E-mail: qgc7605@yahoo.com.cn [Department of Radiology, The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008 (China); Zhou, Zhengyang, E-mail: zyzhou@nju.edu.cn [Department of Radiology, The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008 (China); Qiu, Yong, E-mail: scoliosis2002@sina.com [Spine Service, Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008 (China); Sun, Xizhao, E-mail: sunxizhaonj@163.com [Department of Radiology and Urology, The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, No. 321 Zhongshan Road, Nanjing 210008 (China); Zhu, Bin, E-mail: gobin10266@163.com [Department of Radiology, The Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008 (China)

    2013-08-15

    Purpose: To evaluate the effectiveness of spectral CT in reducing metal artifacts caused by pedicle screws in patients with scoliosis. Materials and methods: Institutional review committee approval and written informed consents from patients were obtained. 18 scoliotic patients with a total of 228 pedicle screws who underwent spectral CT imaging were included in this study. Monochromatic image sets with and without the additional metal artifacts reduction software (MARS) correction were generated with photon energy at 65 keV and from 70 to 140 keV with 10 keV interval using the 80 kVp and 140 kVp projection sets. Polychromatic images corresponded to the conventional 140 kVp imaging were also generated from the same scan data as a control group. Both objective evaluation (screw width and quantitative artifacts index measurements) and subjective evaluation (depiction of pedicle screws, surrounding structures and their relationship) were performed. Results: Image quality of monochromatic images in the range from 110 to 140 keV (0.97 ± 0.28) was rated superior to the conventional polychromatic images (2.53 ± 0.54) and also better than monochromatic images with lower energy. Images of energy above 100 keV also give accurate measurement of the width of screws and relatively low artifacts index. The form of screws was slightly distorted in MARS reconstruction. Conclusions: Compared to conventional polychromatic images, monochromatic images acquired from dual-energy CT provided superior image quality with much reduced metal artifacts of pedicle screws in patients with scoliosis. Optimal energy range was found between 110 and 140 keV.

  17. Distinction between amorphous and healed planar deformation features in shocked quartz using composite color scanning electron microscope cathodoluminescence (SEM-CL) imaging

    NARCIS (Netherlands)

    Hamers, Maartje F.; Pennock, Gill M.; Herwegh, Marco; Drury, Martyn R.

    2016-01-01

    Planar deformation features (PDFs) in quartz are one of the most reliable and most widely used forms of evidence for hypervelocity impact. PDFs can be identified in scanning electron microscope cathodoluminescence (SEM-CL) images, but not all PDFs show the same CL behavior: there are nonluminescent

  18. Spectrally resolved cathodoluminescence imaging study of periodic [001]/[00-1] GaAs structures for nonlinear optical conversion

    Energy Technology Data Exchange (ETDEWEB)

    Hortelano, V.; Martinez, O.; Jimenez, J. [GdS Optronlab., Univ. de Valladolid, Paseo de Belen 1, 47011 Valladolid (Spain); Lynch, C.; Snure, M.; Bliss, D. [Air Force Research Laboratory, Sensors Directorate, Hanscom AFB, MA 01731 (United States)

    2012-07-15

    Orientation patterned (OP)-GaAs crystals are very promising as nonlinear optical materials. They are suitable for mid-infrared and terahertz laser sources, by frequency conversion of shorter wavelength pump sources. OP-GaAs crystals must contain low concentrations of defects and must be homogeneous to reduce fluctuations, in the refractive index and the concomitant optical propagation losses. Understanding of the defects with electrooptic signature is crucial to improve the growth conditions for reducing their presence. Spectrally resolved cathodoluminescence imaging is used to study the main defects and how they are distributed throughout the OP-GaAs crystal (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

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

    Science.gov (United States)

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

    2011-04-01

    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 detail, the three-dimensional diamond zonation adjacent to a diamond inclusion. EBSD reveals that mineral inclusions in a single diamond have similar crystallographic orientations to the host, within ±0.4°. The chromite inclusions record a systematic change in Mg# and Cr# from core to the rim of the diamond that corresponds with a ~80°C decrease of their formation temperature as established by zinc thermometry. A chromite inclusion, positioned adjacent to a boundary between two major diamond growth zones, is multi-faceted with preferred octahedral and cubic faces. The chromite is surrounded by a volume of non-luminescent diamond (CL halo) that partially obscures any diamond growth structures. The CL halo has apparent crystallographic morphology with symmetrically oriented pointed features. The CL halo is enriched in ~200 ppm Cr and ~80 ppm Fe and is interpreted to have a secondary origin as it overprints a major primary diamond growth structure. The diamond zonation adjacent to the chromite is complex and records both syngenetic and protogenetic features based on current inclusion entrapment models. In this specific case, a syngenetic origin is favoured with the complex form of the inclusion and growth layers indicating changes of growth rates at the diamond-chromite interface. Combined EBSD and 3D-CL imaging appears an extremely useful tool in resolving the ongoing discussion about the timing of inclusion growth and the significance of diamond inclusion studies.

  20. Improvement of Image Quality in Transmission Computed Tomography Using Synchrotron Monochromatic X-Ray Sheet Beam

    Science.gov (United States)

    2001-10-25

    7] T. Takeda, M. Kazama, T. Zeniya, T. Yuasa, M. Akiba, A. Uchida, K. Hyodo, T. Akatsuka, M. Ando, and Y. Itai , “Development of a Mono- chromatic X...Uyama (Springer-Verlag, Tokyo), pp. 103-110 (1998). [8] Y. Itai , T. Takeda, T. Akatsuka, T. Maeda, K. Hyodo, A. Uchida, T. Yuasa, M. Kazama, J. Wu...T. Yuasa, K. Hyodo, M. Ando, T. Akatsuka, and Y. Itai , “Performance Study of Monochromatic Synchro- tron X-ray Computed Tomography using a Linear

  1. Dual Energy CT (DECT Monochromatic Imaging: Added Value of Adaptive Statistical Iterative Reconstructions (ASIR in Portal Venography.

    Directory of Open Access Journals (Sweden)

    Liqin Zhao

    Full Text Available To investigate the effect of the adaptive statistical iterative reconstructions (ASIR on image quality in portal venography by dual energy CT (DECT imaging.DECT scans of 45 cirrhotic patients obtained in the portal venous phase were analyzed. Monochromatic images at 70keV were reconstructed with the following 4 ASIR percentages: 0%, 30%, 50%, and 70%. The image noise (IN (standard deviation, SD of portal vein (PV, the contrast-to-noise-ratio (CNR, and the subjective score for the sharpness of PV boundaries, and the diagnostic acceptability (DA were obtained. The IN, CNR, and the subjective scores were compared among the four ASIR groups.The IN (in HU of PV (10.05±3.14, 9.23±3.05, 8.44±2.95 and 7.83±2.90 decreased and CNR values of PV (8.04±3.32, 8.95±3.63, 9.80±4.12 and 10.74±4.73 increased with the increase in ASIR percentage (0%, 30%, 50%, and 70%, respectively, and were statistically different for the 4 ASIR groups (p<0.05. The subjective scores showed that the sharpness of portal vein boundaries (3.13±0.59, 2.82±0.44, 2.73±0.54 and 2.07±0.54 decreased with higher ASIR percentages (p<0.05. The subjective diagnostic acceptability was highest at 30% ASIR (p<0.05.30% ASIR addition in DECT portal venography could improve the 70 keV monochromatic image quality.

  2. Cathodoluminescence of uranium oxides

    Energy Technology Data Exchange (ETDEWEB)

    Winer, K.; Colmenares, C.; Wooten, F.

    1984-08-09

    The cathodoluminescence of uranium oxide surfaces prepared in-situ from clean uranium exposed to dry oxygen was studied. The broad asymmetric peak observed at 470 nm is attributed to F-center excitation.

  3. TU-EF-204-12: Quantitative Evaluation of Spectral Detector CT Using Virtual Monochromatic Images: Initial Results

    Energy Technology Data Exchange (ETDEWEB)

    Duan, X; Guild, J [UT Southwestern Medical Center, Dallas, TX (United States); Arbique, G; Anderson, J [UT Southwestern Medical Ctr at Dallas, Dallas, TX (United States); Dhanantwari, A [Philips Healthcare, Highland Heights, OH (United States); Yagil, Y [Philips Medical Systems, Haifa (Israel)

    2015-06-15

    Purpose To evaluate the image quality and spectral information of a spectral detector CT (SDCT) scanner using virtual monochromatic (VM) energy images. Methods The SDCT scanner (Philips Healthcare) was equipped with a dual-layer detector and spectral iterative reconstruction (IR), which generates conventional 80–140 kV polychromatic energy (PE) CT images using both detector layers, PE images from the low-energy (upper) and high-energy (lower) detector layers and VM images. A solid water phantom with iodine (2.0–20.0 mg I/ml) and calcium (50.0–600.0 mg Ca/ml) rod inserts was used to evaluate effective energy estimate (EEE) and iodine contrast to noise ratio (CNR). The EEE corresponding to an insert CT number in a PE image was calculated from a CT number fit to the VM image set. Since PE image is prone to beam-hardening artifact EEE may underestimate the actual energy separation from two layers of the detector. A 30-cm-diameter water phantom was used to evaluate noise power spectrum (NPS). The phantoms were scanned at 120 and 140 kV with the same CTDIvol. Results The CT number difference for contrast inserts in VM images (50–150 keV) was 1.3±6% between 120 and 140 kV scans. The difference of EEE calculated from low- and high-energy detector images was 11.5 and 16.7 keV for 120 and 140 kV scans, respectively. The differences calculated from 140 and 100 kV conventional PE images were 12.8, and 20.1 keV from 140 and 80 kV conventional PE images. The iodine CNR increased monotonically with decreased keV. Compared to conventional PE images, the peak of NPS curves from VM images were shifted to lower frequency. Conclusion The EEE results indicates that SDCT at 120 and 140 kV may have energy separation comparable to 100/140 kV and 80/140 kV dual-kV imaging. The effects of IR on CNR and NPS require further investigation for SDCT. Author YY and AD are Philips Healthcare employees.

  4. Mapping the Ionization State of Laser-Irradiated Ar Gas Jets With Multi-Wavelength Monochromatic X-Ray Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kugland, N L; Doppner, T; Kemp, A; Schaeffer, D; Glenzer, S H; Niemann, C

    2010-04-08

    Two-dimensional monochromatic images of fast-electron stimulated Ar K{alpha} and He-{alpha} x-ray self-emission have recorded a time-integrated map of the extent of Ar{sup {approx}6+} and Ar{sup 16+} ions, respectively, within a high density (10{sup 20} cm{sup -3} atomic density) Ar plasma. This plasma was produced by irradiating a 2 mm wide clustering Ar gas jet with an ultra-high intensity (10{sup 19} W/cm{sup 2}, 200 fs) Ti:Sapphire laser operating at 800 nm. Spherically bent quartz crystals in the 200 (for K{alpha}) and 201 (for He-{alpha}) planes were used as near-normal incidence reflective x-ray optics. We see that a large (830 {micro}m long) region of plasma emits K{alpha} primarily along the laser axis, while the He-{alpha} emission is confined to smaller hot spot (230 {micro}m long) region that likely corresponds to the focal volume of the f/8 laser beam. X-ray spectra from a Bragg spectrometer operating in the von Hamos geometry, which images in one dimension, indicate that the centroids of the K{alpha} and He-{alpha} emission regions are separated by approximately 330 {micro}m along the laser axis.

  5. Inelastic neutron scattering experiments with the monochromatic imaging mode of the RITA-II spectrometer

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden; Lefmann, Kim; Abrahamsen, Asger Bech;

    2006-01-01

    to perform real inelastic neutron scattering experiments. We present the results from inelastic powder, single crystal dispersion and single crystal constant energy mapping experiments. The advantages and complications of performing these experiments are discussed along with a comparison between the imaging...

  6. New Data On The Cathodoluminescence Of White Marbles: Interpretation Of Peaks And Relationships To Weathering

    Science.gov (United States)

    Garcia-Guinea, J.; Crespo-Feo, E.; Correcher, V.; Iordanidis, A.; Charalampides, G.; Karamitrou-Mentessidi, G.

    This work focus on the Thermoluminescence (TL), the Spatially Resolved Spectral Cathodoluminescence (CL) and Raman spectroscopy (Raman) of white marble specimens collected from the archaeological park of Aiani (Greece) and from patterns of Iceland calcite and Macael marble for comparison purposes. The spectra CL were measured with a high sensitivity cathodoluminescence spectrometer MonoCL3 of Gatan (UK) attached to an FEI-ESEM microscope (CL-ESEM). The experimental set of spectra CL curves of Aiani white marbles suggest that the blue band is more resistant to weathering in comparison with the red band which drops down easily under weathering. The comparison among CL spectra of CaCO3 patterns give a slight difference between the small 330 nm peak, detected in marble and not observed in the monocrystal pattern of Iceland calcite. The Backscattering Electron Dispersed (BSED) images of the white marble are similar to the CL monochromatic plots at 330 nm which highlight the surfaces with remarkable clarity, suggesting a CL emission-defect associated to the marble crystal interfaces, such as protons or hydroxyls. Conversely, the 395 nm monochromatic mapping depicts a CL image emitting from bulk and not from interfaces attributable to point defects or cationic activators in Ca2+ positions. The blue band of the spectra luminescence of marble is composed by several peaks associated to very different types of luminescent defects. This statement is not inconsequential since in archaeological TL dating of marbles the regenerated luminescence in the blue region of the spectrum is a serious difficulty and further research on this topic is necessary.

  7. Atomic Resolution Imaging at an Ultralow Accelerating Voltage by a Monochromatic Transmission Electron Microscope

    Science.gov (United States)

    Morishita, Shigeyuki; Mukai, Masaki; Suenaga, Kazu; Sawada, Hidetaka

    2016-10-01

    Transmission electron microscopy using low-energy electrons would be very useful for atomic resolution imaging of specimens that would be damaged at higher energies. However, the resolution at low voltages is degraded because of geometrical and chromatic aberrations. In the present study, we diminish the effect of these aberrations by using a delta-type corrector and a monochromator. The dominant residual aberration in a delta-type corrector, which is the sixth-order three-lobe aberration, is counterbalanced by other threefold aberrations. Defocus spread caused by chromatic aberration is reduced by using a monochromated beam with an energy spread of 0.05 eV. We obtain images of graphene and demonstrate atomic resolution at an ultralow accelerating voltage of 15 kV.

  8. Distinction between amorphous and healed planar deformation features in shocked quartz using composite color scanning electron microscope cathodoluminescence (SEM-CL) imaging

    Science.gov (United States)

    Hamers, Maartje F.; Pennock, Gill M.; Herwegh, Marco; Drury, Martyn R.

    2016-10-01

    Planar deformation features (PDFs) in quartz are one of the most reliable and most widely used forms of evidence for hypervelocity impact. PDFs can be identified in scanning electron microscope cathodoluminescence (SEM-CL) images, but not all PDFs show the same CL behavior: there are nonluminescent and red luminescent PDFs. This study aims to explain the origin of the different CL emissions in PDFs. Focused ion beam (FIB) thin foils were prepared of specific sample locations selected in composite color SEM-CL images and were analyzed in a transmission electron microscope (TEM). The FIB preparation technique allowed a direct, often one-to-one correlation between the CL images and the defect structure observed in TEM. This correlation shows that composite color SEM-CL imaging allows distinction between amorphous PDFs on one hand and healed PDFs and basal Brazil twins on the other: nonluminescent PDFs are amorphous, while healed PDFs and basal Brazil twins are red luminescent, with a dominant emission peak at 650 nm. We suggest that the red luminescence is the result of preferential beam damage along dislocations, fluid inclusions, and twin boundaries. Furthermore, a high-pressure phase (possibly stishovite) in PDFs can be detected in color SEM-CL images by its blue luminescence.

  9. Initial application of dual energy CT in enterography: monochromatic images of normal intestinal wall%正常回肠壁双能CT成像

    Institute of Scientific and Technical Information of China (English)

    容蓉; 邱建星; 王霄英; 孙晓伟; 蒋学祥

    2012-01-01

    Objective:To evaluate the image quality of CT enterography (CTE) with monochromatic images of dual energy CT. Methods:Eighteen patients underwent CT enterography with dual energy CT (Gemstone spectral imaging,GSI) examinations. The spectrum analysis was used to select the monochromatic images for obtaining the best contrast-to-noise ratio (CNR) for ileum wall. The CNR and image noise of ileum wall at the selected monochromatic level and the conventional polychromatic images were measured. Two readers assessed the image quality, noise and sharpness of both optimal CNR monochromatic level and the conventional polychromatic images. Results: At the selected monochromatic level,the image noise of monochromatic images was higher than that of polychromatic images (fat: 16. 87±2. 73 vs 14. 58±2. 26,t= 3. 85,P<0. 01;fluid: 16. 08±4. 17 vs 13. 51 ±2. 85,t= 4. 96,P<0. 01). The CNR of ileum wall in monochromatic images was also higher than that of polychromatic images (4. 36±0. 71 vs 3. 34±0. 78,t=4. 702,P<0. 01). The intraclass correlation coefficient values among readers for optimal CNR monochromatic images quality was 1. 00. Conclusion: Monochromatic images at optimal CNR keV for CTE can improve CNR for normal ileum wall and improve the overall image quality of CTE.%目的:探讨双能CT小肠成像单能量图像显示正常回肠壁的成像质量及其与混合能量图像在小肠CT成像中的差异.方法:对18例拟诊为炎症性肠病患者行小肠CT成像(CTE),采用双能CT宝石能谱成像技术行CT平扫及双期增强扫描(实质期和延迟期),将实质期图像数据分别进行混合能量和GSI单能量重建,应用能谱分析软件,获得正常回肠壁最佳对比噪声比(CNR)单能图像的KeY值.计算混合能量和单能图像上正常回肠壁的对比噪声比,测量两种图像的噪声并进行配对t检验;由两位医师对两种图像上主动脉锐利度、噪声和图像质量进行主观评分并进行配对t检验,计算组

  10. Abdominal CT: An intra-individual comparison between virtual monochromatic spectral and polychromatic 120-kVp images obtained during the same examination

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Yoshitake, E-mail: yamada@rad.med.keio.ac.jp [Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Jinzaki, Masahiro, E-mail: jinzaki@rad.med.keio.ac.jp [Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Hosokawa, Takahiro, E-mail: snowglobe@infoseek.jp [Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Tanami, Yutaka, E-mail: tanami@rad.med.keio.ac.jp [Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Abe, Takayuki, E-mail: tabe@z5.keio.jp [Center for Clinical Research, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan); Kuribayashi, Sachio, E-mail: skuribay@med.keio.ac.jp [Department of Diagnostic Radiology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582 (Japan)

    2014-10-15

    Highlights: • We compared virtual monochromatic spectral (VMS) images with 120-kVp images. • VMS images are generated using accurate two-material beam-hardening correction. • Abdominal 70-keV VMS images provide better image quality than 120-kVp images. • Iterative reconstruction can further improve the image quality of VMS images. - Abstract: Objectives: To compare quantitative and subjective image quality between virtual monochromatic spectral (VMS) and conventional polychromatic 120-kVp imaging performed during the same abdominal computed tomography (CT) examination. Materials and methods: Our institutional review board approved this prospective study; each participant provided written informed consent. 51 patients underwent sequential fast kVp-switching dual-energy (80/140 kVp, volume CT dose index: 12.7 mGy) and single-energy (120-kVp, 12.7 mGy) abdominal enhanced CT over an 8 cm scan length with a random acquisition order and a 4.3-s interval. VMS images with filtered back projection (VMS-FBP) and adaptive statistical iterative reconstruction (so-called hybrid IR) (VMS-ASIR) (at 70 keV), as well as 120-kVp images with FBP (120-kVp-FBP) and ASIR (120-kVp-ASIR), were generated from dual-energy and single-energy CT data, respectively. The objective image noises, signal-to-noise ratios and contrast-to-noise ratios of the liver, kidney, pancreas, spleen, portal vein and aorta, and the lesion-to-liver and lesion-to-kidney contrast-to-noise ratios were measured. Two radiologists independently and blindly assessed the subjective image quality. The results were analyzed using the paired t-test, Wilcoxon signed rank sum test and mixed-effects model with Bonferroni correction. Results: VMS-ASIR images were superior to 120-kVp-FBP, 120-kVp-ASIR and VMS-FBP images for all the quantitative assessments and the subjective overall image quality (all P < 0.001), while VMS-FBP images were superior to 120-kVp-FBP and 120-kVp-ASIR images (all P < 0.004). Conclusions: VMS

  11. An important criterion for reliable multi-monochromatic x-ray imager diagnostics and its impact on the reconstructed images

    Institute of Scientific and Technical Information of China (English)

    T.Nagayama; R.C.Mancini; D.Mayes; R.Tommasini; R.Florido

    2015-01-01

    Temperature and density asymmetry diagnosis is critical to advance inertial confinement fusion(ICF) science. A multimonochromatic x-ray imager, MMI, records the spectral signature from an ICF implosion core with time resolution, 2D spatial resolution and spectral resolution. While narrow-band images and 2D space-resolved spectra from the MMI data constrain the temperature and the density spatial structure of the core, the accuracy of the images and the spectra highly depends on the quality of the MMI data and the processing tools. Here, we synthetically investigate the criterion for reliable MMI diagnostics and its effects on the accuracy of the reconstructed images. The pinhole array tilt determines the object spatial sampling efficiency and the minimum reconstruction width, w. When the spectral width associated with w is significantly narrower than the spectral linewidth, the line images reconstructed from the MMI data become reliable. The MMI setup has to be optimized for every application to meet this criterion for reliable ICF diagnostics.

  12. Analysis and interpretation of the first monochromatic X-ray tomography data collected at the Australian Synchrotron Imaging and Medical beamline.

    Science.gov (United States)

    Stevenson, Andrew W; Hall, Christopher J; Mayo, Sheridan C; Häusermann, Daniel; Maksimenko, Anton; Gureyev, Timur E; Nesterets, Yakov I; Wilkins, Stephen W; Lewis, Robert A

    2012-09-01

    The first monochromatic X-ray tomography experiments conducted at the Imaging and Medical beamline of the Australian Synchrotron are reported. The sample was a phantom comprising nylon line, Al wire and finer Cu wire twisted together. Data sets were collected at four different X-ray energies. In order to quantitatively account for the experimental values obtained for the Hounsfield (or CT) number, it was necessary to consider various issues including the point-spread function for the X-ray imaging system and harmonic contamination of the X-ray beam. The analysis and interpretation of the data includes detailed considerations of the resolution and efficiency of the CCD detector, calculations of the X-ray spectrum prior to monochromatization, allowance for the response of the double-crystal Si monochromator used (via X-ray dynamical theory), as well as a thorough assessment of the role of X-ray phase-contrast effects. Computer simulations relating to the tomography experiments also provide valuable insights into these important issues. It was found that a significant discrepancy between theory and experiment for the Cu wire could be largely resolved in terms of the effect of the point-spread function. The findings of this study are important in respect of any attempts to extract quantitative information from X-ray tomography data, across a wide range of disciplines, including materials and life sciences.

  13. Confocal filtering in cathodoluminescence microscopy of nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Narváez, Angela C., E-mail: a.c.narvaez@tudelft.nl, E-mail: j.p.hoogenboom@tudelft.nl; Weppelman, I. Gerward C.; Moerland, Robert J.; Hoogenboom, Jacob P., E-mail: a.c.narvaez@tudelft.nl, E-mail: j.p.hoogenboom@tudelft.nl; Kruit, Pieter [Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628CJ Delft (Netherlands)

    2014-06-23

    Cathodoluminescence (CL) microscopy allows optical characterization of nanostructures at high spatial resolution. At the nanoscale, a main challenge of the technique is related to the background CL generated within the sample substrate. Here, we implement confocal detection of the CL signal to minimize the background contribution to the measurement. Nano-phosphors were used as point sources to evaluate the filtering capabilities of our confocal CL system, obtaining an axial intensity profile with 2.7 μm full width at half maximum for the central peak, in good correspondence with theoretical expectations. Considering the electron interaction volume, we found that the confocal filter becomes effective for electron energies above 20 keV, when using a 25 μm pinhole (0.86 Airy units). To illustrate our approach, we present confocal CL imaging of gold nanowires and triangular shaped plates deposited on an indium-tin oxide covered glass substrate, comparing the images with those obtained in standard unfiltered CL detection. The results show that confocal CL microscopy is a valuable tool for the investigation of nanostructures on highly cathodoluminescent substrates, widely used in biological and optical applications.

  14. Photoinitiation and Inhibition under Monochromatic Green Light for Storage of Colored 3D Images in Holographic Polymer-Dispersed Liquid Crystals.

    Science.gov (United States)

    Chen, Guannan; Ni, Mingli; Peng, Haiyan; Huang, Feihong; Liao, Yonggui; Wang, Mingkui; Zhu, Jintao; Roy, V A L; Xie, Xiaolin

    2017-01-18

    Holographic photopolymer composites have garnered a great deal of interest in recent decades, not only because of their advantageous light sensitivity but also due to their attractive capabilities of realizing high capacity three-dimensional (3D) data storage that is long-term stable within two-dimensional (2D) thin films. For achieving high performance holographic photopolymer composites, it is of critical importance to implement precisely spatiotemporal control over the photopolymerization kinetics and gelation during holographic recording. Though a monochromatic blue light photoinitibitor has been demonstrated to be useful for improving the holographic performance, it is impractical to be employed for constructing holograms under green light due to the severe restriction of the First Law of Photochemistry, while holography under green light is highly desirable considering the relatively low cost of laser source and high tolerance to ambient vibration for image reconstruction. Herein, we disclose the concurrent photoinitiation and inhibition functions of the rose bengal (RB)/N-phenylglycine (NPG) system upon green light illumination, which result in significant enhancement of the diffraction efficiency of holographic polymer-dispersed liquid crystal (HPDLC) gratings from zero up to 87.6 ± 1.3%, with an augmentation of the RB concentration from 0.06 × 10(-3) to 9.41 × 10(-3) mol L(-1). Interestingly, no detectable variation of the ϕ(1/2)kp/kt(1/2), which reflects the initiation efficiency and kinetic constants, is given when increasing the RB concentration. The radical inhibition by RBH(•) is believed to account for the greatly improved phase separation and enhanced diffraction efficiency, through shortening the weight-average polymer chain length and subsequently delaying the photopolymerization gelation. The reconstructed colored 3D images that are easily identifiable to the naked eye under white light demonstrate great potential to be applied for advanced

  15. Monochromatic subdiffusive spatial frequency domain imaging provides in-situ sensitivity to intratumoral morphological heterogeneity in a murine model.

    Science.gov (United States)

    McClatchy, David M; Hoopes, P Jack; Pogue, Brian W; Kanick, Stephen Chad

    2017-02-01

    For the first time, spatially resolved quantitative metrics of light scattering recovered with sub-diffusive spatial frequency domain imaging (sd-SFDI) are shown to be sensitive to changes in intratumoral morphology and viability by direct comparison to histopathological analysis. Two freshly excised subcutaneous murine tumor cross-sections were measured with sd-SFDI, and recovered optical scatter parameter maps were co-registered to whole mount histology. Unique clustering of the optical scatter parameters μs' vs. γ (i.e. diffuse scattering vs. relative backscattering) evaluated at a single wavelength showed complete separation between regions of viable tumor, aggresive tumor with stromal growth, varying levels of necrotic tumor, and also peritumor muscle. The results suggest that with further technical development, sd-SFDI may represent a non-destructive screening tool for analysis of excised tissue or a non-invasive approach to investigate suspicious lesions without the need for exogenous labels or spectrally resolved imaging. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. (U) Estimating the Photonics Budget, Resolution, and Signal Requirements for a Multi-Monochromatic X-ray Imager

    Energy Technology Data Exchange (ETDEWEB)

    Tregillis, Ian Lee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-22

    This document examines the performance of a generic flat-mirror multimonochromatic imager (MMI), with special emphasis on existing instruments at NIF and Omega. We begin by deriving the standard equation for the mean number of photons detected per resolution element. The pinhole energy bandwidth is a contributing factor; this is dominated by the finite size of the source and may be considerable. The most common method for estimating the spatial resolution of such a system (quadrature addition) is, technically, mathematically invalid for this case. However, under the proper circumstances it may produce good estimates compared to a rigorous calculation based on the convolution of point-spread functions. Diffraction is an important contribution to the spatial resolution. Common approximations based on Fraunhofer (farfield) diffraction may be inappropriate and misleading, as the instrument may reside in multiple regimes depending upon its configuration or the energy of interest. It is crucial to identify the correct diffraction regime; Fraunhofer and Fresnel (near-field) diffraction profiles are substantially different, the latter being considerably wider. Finally, we combine the photonics and resolution analyses to derive an expression for the minimum signal level such that the resulting images are not dominated by photon statistics. This analysis is consistent with observed performance of the NIF MMI.

  17. Coupling between creep and redox behavior in nickel - yttria stabilized zirconia observed in-situ by monochromatic neutron imaging

    Science.gov (United States)

    Makowska, Malgorzata Grazyna; Kuhn, Luise Theil; Frandsen, Henrik Lund; Lauridsen, Erik Mejdal; De Angelis, Salvatore; Cleemann, Lars Nilausen; Morgano, Manuel; Trtik, Pavel; Strobl, Markus

    2017-02-01

    Ni-YSZ (nickel - yttria stabilized zirconia) is a material widely used for electrodes and supports in solid oxide electrochemical cells. The mechanical and electrochemical performance of these layers, and thus the whole cell, depends on their microstructure. During the initial operation of a cell, NiO is reduced to Ni. When this process is conducted under external load, like also present in a stack assembly, significant deformations of NiO/Ni-YSZ composite samples are observed. The observed creep is orders of magnitude larger than the one observed after reduction during operation. This phenomenon is referred to as accelerated creep and is expected to have a significant influence on the microstructure development and stress field present in the Ni-YSZ in solid oxide electrochemical cells (SOCs), which is highly important for the durability of the SOC. In this work we present energy selective neutron imaging studies of the accelerated creep phenomenon in Ni/NiO-YSZ composite during reduction and also during oxidation. This approach allowed us to observe the phase transition and the creep behavior simultaneously in-situ under SOC operation-like conditions.

  18. Cathodoluminescence and its application in the planetary sciences

    CERN Document Server

    Gucsik, Arnold

    2009-01-01

    This book provides an overview of cathodoluminescence properties of the planetary materials. It provides a unique introduction to cathodoluminescence which is widely used in the geosciences, because it is a non-destructive and "easy to use" method.

  19. 对数螺旋型劳厄弯晶的X射线单色成像应用%Logarithmic Spiral Bent Laue Crystals for X-Ray Monochromatic Imaging Applications

    Institute of Scientific and Technical Information of China (English)

    毋玉芬; 肖沙里; 鲁建; 钱家渝; 刘利锋; 黄显宾

    2013-01-01

    Taking advantages of the monochromatic X-ray diffraction property of Laue crystals,an innovative use of logarithmic spiral bent Laue crystals for X-ray monochromatic imaging is investigated.According to the ray tracing method and the surface equation of the logarithmic spiral,the imaging principles and characteristics of the logarithmic spiral bent Laue crystals are studied,including the condition that the diffracted beam can be separated from the transmitted beam,the magnifications and the field of view (FOV).A logarithmic spiral bent quartz (1010) Laue crystal analyzer is developed.With the proposed crystal analyzer,the monochromatic backlight imaging experiment for the mesh grid with a diameter of 50 μm is carried out by taking an X-ray source of Cu target as the backlighter.The experimental results show that the spatial resolution of the analyzer is approximately 11.9 μm under a source diameter of 110 μm.Furthermore,the FOVs of the crystal analyzer are 22.3557 mm and 8.2602 mm in horizontal and vertical directions,respectively.%利用劳厄晶体研究了X射线的单色衍射性质,研究了对数螺旋型劳厄弯晶在等离子体X射线单色成像中的应用.根据光线追迹原理及对数螺旋线的表面方程,研究了对数螺旋型劳厄弯晶的单色成像原理,分析了单色衍射像不受透射白光X射线影响的准则,以及子午、弧矢放大倍数和单色成像视场等性能参数.研制了石英晶体(1010)对数螺旋劳厄弯晶分析器,以铜靶X射线源作为背光源,对网丝直径为50 μm的金属网格进行了单色背光成像实验.实验结果表明,当背光源尺寸为110 μm时,对数螺旋型劳厄弯晶的空间分辨力约为11.9μm,分析器在子午和弧矢方向的视场分别达到22.3557 mm和8.2602 mm.

  20. Cathodoluminescence Microscopy of Nanostructures on Transparent Substrates

    NARCIS (Netherlands)

    Narváez, A.C.

    2014-01-01

    Cathodoluminescence (CL), the excitation of light by an electron beam, has gained attention as an analysis tool for investigating the optical response of a structure, at a resolution that approaches that in electron microscopy, in the nanometer range. However, the application possibilities are limit

  1. Cathodoluminescence Microscopy of nanostructures on glass substrates

    NARCIS (Netherlands)

    Narvaez, A.C.; Weppelman, I.G.C.; Moerland, R.J.; Liv, N.; Zonnevylle, A.C.; Kruit, P.; Hoogenboom, J.P.

    2013-01-01

    Cathodoluminescence (CL) microscopy is an emerging analysis technique in the fields of biology and photonics, where it is used for the characterization of nanometer sized structures. For these applications, the use of transparent substrates might be highly preferred, but the detection of CL from nan

  2. The Clinical Value of CT Enterography with Spectral Monochromatic Imaging for Crohn's Disease%能谱CT单能量小肠成像应用于克罗恩病临床评估的价值

    Institute of Scientific and Technical Information of China (English)

    石桥; 谢婷婷; 袁知东; 邓乾华; 言伟强; 郭学军

    2016-01-01

    Objective To evaluate the value of CT enterography with spectral monochromatic imaging for Crohn's disease.Methods 48 cases of clinically diagnosed Crohn's disease underwent CT spectral imaging. Contrast-to-noise ratio (CNR) analysis was performed to obtain the best monochromatic imaging. Observation indicators include intestinal lesions position, intestinal wall thickness, intestinal stenosis, intestinal enhancement level, manifestation around intestine (serosal layer, fat space, mesentery vascular), lymph node enlargement and related complications. Enhancement rate of normal bowel wall and lesions in the segments of intestine on arterial phase(△A%) and venous phase(△V%) were calculated. All patients underwent endoscopic (colonoscopy or endoscopy) examination, 2 patients underwent surgical treatment.Results CT enterography with spectral monochromatic imaging combined with material separation function could clearly display the intestinal lesions range and position and revealed a total of 132 lesions of the bowel segment. The intestinal wall thickness was between 3.1 to 26 mm. The jejunum were involved in 9 cases, 39 cases of ileal involvement and ileocecal involvement in 42 cases, colorectal lesion of 29 patients. 25 cases displayed bowel wall edema and enhancement of concentric circles or layered like change, 39 cases displayed fuzzy of serous layer, 18 cases displayed fuzzy of fat space around the intestine, 36 displayed increasing of mesenteric vessel, in which, 24 cases were observed obvious "comb like" sign. 22 cases were observed having mesenteric and retroperitoneal lymph node enlargement. Complications included Intestinal perforation with abdominal abscess formation occurred in one patient, anal fistula occurred in 3 cases and incomplete intestinal obstruction in 4 cases, 2 cases bowel stenosis with retention of capsule endoscopy. CT value of intestinal wall lesion and normal intestinal wall had no significant difference (P>0.05) on plain scan image

  3. 体外实验中宝石CT能谱成像技术血管成像最佳单能量图像的选择%In vitro optimal monochromatic image for CT vasculargraphy using gemstone spectral imaging technique

    Institute of Scientific and Technical Information of China (English)

    汪洁; 王万勤; 刘斌; 王乐; 张帅

    2011-01-01

    Objective To investigate the optimal monochromatic image for CT vasculargraphy using gemstone spectral imaging (GSI) in vitro. Methods Ten test tubes of solution varied in iodine concentrations (1. 04, 1. 17, 1. 56, 2. 08, 2. 34, 3. 13, 4. 17, 4. 69, 6. 25, 9. 38 mgl/ml) embedded in pork which were fixed in a water tank. The tank was scanned with spectral CT using GSI mode. All the data were transferred to GSI viewer to obtain a set of polychromatic images (140 kVp) and 7 sets of monochromatic images (40-70 keV, interval of 5 keV). CNR, SNR and noise were compared a-mong 7 sets monochromatic images and polychromatic images. The image quality was assessed according to sharp-edged degree of the test tube, displaying of muscle and fat as well as the noise. Results CNR of 50 keV (13. 28±3. 06) and 55 keV (14. 68±3. 75) images were the highest in all sets of monochromatic images and polychromatic images (P<0. 001). There was no significant difference between 50 keV and 55 keV (P = 0. 139). SNR of 55 keV image (22. 18±3. 95) was the highest in all sets of monochromatic images and polychromatic images (P<0. 001). Compared to the polychromatic image, reduction of the noise of 65 keV image (23. 08%) was higher than those of other monochromatic images. And the subjective image quality scales in 55 keV (11. 76±0. 33) were the highest in all sets of monochromatic images and polychromatic images (x2 =73. 05, P<0. 001). Conclusion In GSI of vasculargraphy, 55 keV is the optimal monochromatic level for in vitro CT vasculargraphy to offer the overall good image quality, imaging quality is better than that of polychromatic images.%目的 通过体外实验探讨宝石CT能谱成像(GSI)技术血管成像的最佳单能量图像.方法 将非离子型对比剂(碘海醇,300 mgI/ml)用生理盐水稀释成10种不同浓度的溶液置于2 ml硬塑料试管中,浓度依次为1.04、1.17、1.56、2.08、2.34、3.13、4.17、4.69、6.25及9.38 mgl/ml.用猪肉包裹试管后置入

  4. Evaluation of monochromatic imaging spectal CT for intestinal bleeding using an experimental pig intestine model%能谱CT单能量成像诊断活动性小肠出血的实验研究

    Institute of Scientific and Technical Information of China (English)

    刘文冬; 吴兴旺; 刘斌; 李红文; 王斌

    2014-01-01

    Objective To discuss the diagnostic value of monochromatic energy image spectral CT in active small bowel bleeding and to screen the optimal energy level that indicates active bleeding of the gastrointestinal tract.Methods The bleeding model was established using the small intestines of pigs in vitro.Seven blood flow rates were simulated:0.500,0.400,0.300,0.200,0.100,0.050,0.025 ml/min,respectively.For each rate,a GE Discovery HD750 CT scanner was used in GSI scan mode and 64 slice CT was performed,with a delay of 15 s and 40 s simulated the arterial phase and portal venous phase,respectively.Each out of the blood flow rate in the 2 modes was respectively scanned 5 times.The GSI reconstruction platform was employed to obtain 7 monochromatic energy images(40,50,60,70,80,90,100 keV).A set of polychromatic energy images was obtained from an ordinary scan.The detection rates of the contrast agent exudation regions using the two scanning methods were compared.The contrast to noise ratios(CNR) for the contrast agent exudation regions were measured.Randomized block analysis of Variance was performed to compare the differences in CNR between energy levels.The x2 test was used to compare the detection rates obtained from the 2 scanning methods.Results The detection rates for energy spectral CT and 64 slice CT in the arterial phase were 31/35 and 23/35,respectively; there was significant difference(x2=5.185,P=0.023).The total detection rates of portal venous phase were 35/35 and 32/35,respectively,there was no significant difference(x2=l.393,P=0.238).On the ordinary scan mode,the detection rates of arterial and portal venous phase difference was statistically significant(x2 =6.873,P =0.009);but on the GSI scan mode,there was no significant difference(x2=2.386,P=0.122). The CNR values at 8 group energy levels for arterial phase and portal venous phase were statistically different(respectively P< 0.05),the CNR value of the contrast agent exudation regions at 50 keV and 60 ke

  5. Monochromatic gamma emitter for low energy quanta

    CERN Document Server

    Tomova, Z R; Mironova, S A

    2004-01-01

    The possibility of creating of a monochromatic gamma emitter of low energy quanta is analyzed. The idea is based on Daning's scheme. Except for purely scientific problems the monochromator is actual for therapy of wide range of diseases.

  6. Multilayer optics for monochromatic high-resolution X-ray imaging diagnostic in a broad photon energy range from 2 keV to 22 keV

    Energy Technology Data Exchange (ETDEWEB)

    Troussel, Ph., E-mail: philippe.troussel@cea.fr [CEA, DAM, DIF, F-91297 Arpajon (France); Dennetiere, D. [Synchrotron Soleil, L’orme des Merisiers, 91190 Saint-Aubin (France); Maroni, R. [CEA, DAM, DIF, F-91297 Arpajon (France); Høghøj, P.; Hedacq, S. [Xenocs SA, 19, rue François Blumet, F-38360 Sassenage (France); Cibik, L.; Krumrey, M. [Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin (Germany)

    2014-12-11

    The “Commissariat à l’énergie atomique et aux énergies alternatives” (CEA) studies and designs advanced X-ray diagnostics to probe dense plasmas produced at the future Laser MegaJoule (LMJ) facility. Mainly for X-ray imaging with high spatial resolution, different types of multilayer mirrors were developed to provide broadband X-ray reflectance at grazing incidence. These coatings are deposited on two toroidal mirror substrates that are then mounted into a Wolter-type geometry (working at a grazing angle of 0.45°) to realize an X-ray microscope. Non-periodic (depth graded) W/Si multilayer can be used in the broad photon energy range from 2 keV to 22 keV. A third flat mirror can be added for the spectral selection of the microscope. This mirror is coated with a Mo/Si multilayer for which the d-spacing varies in the longitudinal direction to satisfy the Bragg condition within the angular acceptance of the microscope and also to compensate the angular dispersion due to the field of the microscope. We present a study of such a so-called Göbel mirror which was optimized for photon energy of 10.35 keV. The three mirrors were coated using magnetron sputtering technology by Xenocs SA. The reflectance in the entire photon energy range was determined in the laboratory of the Physikalisch-Technische Bundesanstalt (PTB) at the synchrotron radiation facility BESSY II in Berlin.

  7. Cathodoluminescence spectra of gallium nitride nanorods.

    Science.gov (United States)

    Tsai, Chia-Chang; Li, Guan-Hua; Lin, Yuan-Ting; Chang, Ching-Wen; Wadekar, Paritosh; Chen, Quark Yung-Sung; Rigutti, Lorenzo; Tchernycheva, Maria; Julien, François Henri; Tu, Li-Wei

    2011-12-14

    Gallium nitride [GaN] nanorods grown on a Si(111) substrate at 720°C via plasma-assisted molecular beam epitaxy were studied by field-emission electron microscopy and cathodoluminescence [CL]. The surface topography and optical properties of the GaN nanorod cluster and single GaN nanorod were measured and discussed. The defect-related CL spectra of GaN nanorods and their dependence on temperature were investigated. The CL spectra along the length of the individual GaN nanorod were also studied. The results reveal that the 3.2-eV peak comes from the structural defect at the interface between the GaN nanorod and Si substrate. The surface state emission of the single GaN nanorod is stronger as the diameter of the GaN nanorod becomes smaller due to an increased surface-to-volume ratio.

  8. Cathodoluminescence for the 21st Century: Learning More from Light

    Energy Technology Data Exchange (ETDEWEB)

    Haegel, Nancy M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Coenen, T. [DELMIC B.V.

    2017-09-08

    Cathodoluminescence (CL) is the emission of light from a material in response to excitation by incident electrons. The technique has had significant impact in the characterization of semiconductors, minerals, ceramics, and many nanostructured materials. Since 2010, there have been a number of innovative developments that have revolutionized and expanded the information that can be gained from CL and broadened the areas of application. While the primary historical application of CL was for spatial mapping of luminescence variations (e.g., imaging dark line defects in semiconductor lasers or providing high resolution imaging of compositional variations in geological materials), new ways to collect and analyze the emitted light have expanded the science impact of CL, particularly at the intersection of materials science and nanotechnology. These developments include (1) angular and polarized CL, (2) advances in time resolved CL, (3) far-field and near-field transport imaging that enable drift and diffusion information to be obtained through real space imaging, (4) increasing use of statistical analyses for the study of grain boundaries and interfaces, (5) 3D CL including tomography and combined work utilizing dual beam systems with CL, and (6) combined STEM/CL measurements that are reaching new levels of resolution and advancing single photon spectroscopy. This focused review will first summarize the fundamentals and then briefly describe the state-of-the-art in conventional CL imaging and spectroscopy. We then review these recent novel experimental approaches that enable added insight and information, providing a range of examples from nanophotonics, photovoltaics, plasmonics, and studies of individual defects and grain boundaries.

  9. Cathodoluminescence for the 21st century: Learning more from light

    Science.gov (United States)

    Coenen, T.; Haegel, N. M.

    2017-09-01

    Cathodoluminescence (CL) is the emission of light from a material in response to excitation by incident electrons. The technique has had significant impact in the characterization of semiconductors, minerals, ceramics, and many nanostructured materials. Since 2010, there have been a number of innovative developments that have revolutionized and expanded the information that can be gained from CL and broadened the areas of application. While the primary historical application of CL was for spatial mapping of luminescence variations (e.g., imaging dark line defects in semiconductor lasers or providing high resolution imaging of compositional variations in geological materials), new ways to collect and analyze the emitted light have expanded the science impact of CL, particularly at the intersection of materials science and nanotechnology. These developments include (1) angular and polarized CL, (2) advances in time resolved CL, (3) far-field and near-field transport imaging that enable drift and diffusion information to be obtained through real space imaging, (4) increasing use of statistical analyses for the study of grain boundaries and interfaces, (5) 3D CL including tomography and combined work utilizing dual beam systems with CL, and (6) combined STEM/CL measurements that are reaching new levels of resolution and advancing single photon spectroscopy. This focused review will first summarize the fundamentals and then briefly describe the state-of-the-art in conventional CL imaging and spectroscopy. We then review these recent novel experimental approaches that enable added insight and information, providing a range of examples from nanophotonics, photovoltaics, plasmonics, and studies of individual defects and grain boundaries.

  10. Thermo- and cathodoluminescence properties of Sepiolite

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez L, Y. [Universidad Autonoma de Nayarit, Ciudad de la cultura Amado Nervo s/n, 63155 Tepic, Nayarit (Mexico); Correcher, V. [CIEMAT, Av. Complutense 22, 28040 Madrid (Spain); Garcia G, J., E-mail: yamilet.lazcano@uan.edu.mx [Consejo Superior de Investigaciones Cientificas, Museo Nacional de Ciencias Naturales, Jose Gutierrez Abascal 2, 28006 Madrid (Spain)

    2015-10-15

    Full text: Sepiolite, Si{sub 12}Mg{sub 8}O{sub 30}(OH){sub 4}(OH{sub 2}){sub 4}·8H{sub 2}O, has been well studied from the chemical and structural point of view; however, studies on their luminescence properties have been scarcely reported. This work focuses on the thermoluminescence (Tl) and cathodoluminescence (Cl) response of a natural sepiolite from Madrid, Spain previously characterized by means of environmental scanning electron microscope, X-ray fluorescence (X RF) and X-ray diffraction (XRD) techniques. The complexity of the thermoluminescence glow curves of non-irradiated and irradiated samples suggests a structure of a continuous trap distribution involving multi-order kinetics. UV-IR Cl spectral emission shows five peaks centered at 330, 400, 440, 520 and 770 nm. Such emission bands could be due to (i) structural defects, [AlO{sub 4}] or non bridging oxygen hole centers, and (II) the presence of point defects associated with Mn{sup 2+} and Fe{sup 3+}. Sepiolite, which has different household applications such as: moisture control, containment of accidental liquid spillages, in ashtrays to avoid smoke odor, control of liquid leakages, and odours in dustbins and cat litters; is a good candidate for personal dosimetry in the case of radiation accident or radiological terrorism. in situations where knowledge of doses to individuals is required, but monitoring was not planned. (Author)

  11. Cathodoluminescence of natural, plastically deformed pink diamonds.

    Science.gov (United States)

    Gaillou, E; Post, J E; Rose, T; Butler, J E

    2012-12-01

    The 49 type I natural pink diamonds examined exhibit color restricted to lamellae or bands oriented along {111} that are created by plastic deformation. Pink diamonds fall into two groups: (1) diamonds from Argyle in Australia and Santa Elena in Venezuela are heavily strained throughout and exhibit pink bands alternating with colorless areas, and (2) diamonds from other localities have strain localized near the discrete pink lamellae. Growth zones are highlighted by a blue cathodoluminescence (CL) and crosscut by the pink lamellae that emit yellowish-green CL that originates from the H3 center. This center probably forms by the recombination of nitrogen-related centers (A-aggregates) and vacancies mobilized by natural annealing in the Earth's mantle. Twinning is the most likely mechanism through which plastic deformation is accommodated for the two groups of diamonds. The plastic deformation creates new centers visible through spectroscopic methods, including the one responsible for the pink color, which remains unidentified. The differences in the plastic deformation features, and resulting CL properties, for the two groups might correlate to the particular geologic conditions under which the diamonds formed; those from Argyle and Santa Elena are deposits located within Proterozoic cratons, whereas most diamonds originate from Archean cratons.

  12. Cathodoluminescence degradation of PLD thin films

    Science.gov (United States)

    Swart, H. C.; Coetsee, E.; Terblans, J. J.; Ntwaeaborwa, O. M.; Nsimama, P. D.; Dejene, F. B.; Dolo, J. J.

    2010-12-01

    The cathodoluminescence (CL) intensities of Y2SiO5:Ce3+, Gd2O2S:Tb3+ and SrAl2O4:Eu2+,Dy3+ phosphor thin films that were grown by pulsed laser deposition (PLD) were investigated for possible application in low voltage field emission displays (FEDs) and other infrastructure applications. Several process parameters (background gas, laser fluence, base pressure, substrate temperature, etc.) were changed during the deposition of the thin films. Atomic force microscopy (AFM) was used to determine the surface roughness and particle size of the different films. The layers consist of agglomerated nanoparticle structures. Samples with good light emission were selected for the electron degradation studies. Auger electron spectroscopy (AES) and CL spectroscopy were used to monitor changes in the surface chemical composition and luminous efficiency of the thin films. AES and CL spectroscopy were done with 2 keV energy electrons. Measurements were done at 1×10-6 Torr oxygen pressure. The formation of different oxide layers during electron bombardment was confirmed with X-ray photoelectron spectroscopy (XPS). New non-luminescent layers that formed during electron bombardment were responsible for the degradation in light intensity. The adventitious C was removed from the surface in all three cases as volatile gas species, which is consistent with the electron stimulated surface chemical reaction (ESSCR) model. For Y2SiO5:Ce3+ a luminescent SiO2 layer formed during the electron bombardment. Gd2O3 and SrO thin films formed on the surfaces of Gd2O2S:Tb3+ and SrAl2O4:Eu2+,Dy3+, respectively, due to ESSCRs.

  13. The selection of monochromatic images in the post process of hepatic arterial CT angiology before TACE%肝癌化疗栓塞术前肝动脉能谱CT成像中最佳单能量的选择

    Institute of Scientific and Technical Information of China (English)

    孙奕波; 李铭; 毛定彪; 白爱国; 齐琳; 任庆国; 高丰; 杨艳丽; 陆芳

    2013-01-01

    Objective To investigate the value of using optimal contrast noise ratio to select one optimal keV monochromatic images to improve image quality of hepatic arterial CT angiology before transcatheter arterial chemoembolization.Methods 96 patients with hepatic malignant tumors were underwent spectral CT examination from October 2011 to October 2012.There were 52 males and 44 females with ages ranging from 51 to 62 years(mean age of 57.61 years).Using GE ADW 4.4 and GSI view software to post process the images and measure optimal CNR in transverse image to select an optimal keV monochromatic images.Measure contrast and noise of proper hepatic artery and the right hepatic artery in QC images,predefine keV monochromatic images selected by system and monochromatic images select by using optimal contrast noise ratio.Two radiologists major in abdominal and vascular radiology evaluate those images using score 1-5.Statistical analysis was carried out using the Stata version 10.0 software.P < 0.05 was defined as statistical significance.Results The score,contrast and noise of monochromatic images select by using optimal contrast noise ratio was significantly higher than other two methods,and those of monochromatic images selected by system was significantly higher than QC images(P <0.05).Conclusions Using optimal contrast noise ratio to select one keV monochromatic images set will enhance contrast between hepatic arteries and surrounding tissue,make arteries more visible and improve image quality of hepatic arterial CT angiology.%目的 探讨选择最佳对比信噪比(CNR)获得最理想keV单能量图像质量以指导肝癌肝动脉化疗栓塞术的价值.方法 收集我院2011年10月至2012年10月临床诊断无手术切除指征的肝细胞癌患者96例(其中男52例,女44例),采用GE Discovaery 750 HDCT扫描,范围从膈顶至双肾下极.图像后处理采用ADW 4.4工作站和GSI-view软件,在单能量轴位图像上测量最佳CNR,并从101个单能

  14. FIB-SEM cathodoluminescence tomography: practical and theoretical considerations.

    Science.gov (United States)

    De Winter, D A M; Lebbink, M N; Wiggers De Vries, D F; Post, J A; Drury, M R

    2011-09-01

    Focused ion beam-scanning electron microscope (FIB-SEM) tomography is a powerful application in obtaining three-dimensional (3D) information. The FIB creates a cross section and subsequently removes thin slices. The SEM takes images using secondary or backscattered electrons, or maps every slice using X-rays and/or electron backscatter diffraction patterns. The objective of this study is to assess the possibilities of combining FIB-SEM tomography with cathodoluminescence (CL) imaging. The intensity of CL emission is related to variations in defect or impurity concentrations. A potential problem with FIB-SEM CL tomography is that ion milling may change the defect state of the material and the CL emission. In addition the conventional tilted sample geometry used in FIB-SEM tomography is not compatible with conventional CL detectors. Here we examine the influence of the FIB on CL emission in natural diamond and the feasibility of FIB-SEM CL tomography. A systematic investigation establishes that the ion beam influences CL emission of diamond, with a dependency on both the ion beam and electron beam acceleration voltage. CL emission in natural diamond is enhanced particularly at low ion beam and electron beam voltages. This enhancement of the CL emission can be partly explained by an increase in surface defects induced by ion milling. CL emission enhancement could be used to improve the CL image quality. To conduct FIB-SEM CL tomography, a recently developed novel specimen geometry is adopted to enable sequential ion milling and CL imaging on an untilted sample. We show that CL imaging can be manually combined with FIB-SEM tomography with a modified protocol for 3D microstructure reconstruction. In principle, automated FIB-SEM CL tomography should be feasible, provided that dedicated CL detectors are developed that allow subsequent milling and CL imaging without manual intervention, as the current CL detector needs to be manually retracted before a slice can be milled

  15. Contrast and decay of cathodoluminescence from phosphor particles in a scanning electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Engelsen, Daniel den; Harris, Paul G.; Ireland, Terry G., E-mail: terry.ireland@brunel.ac.uk; Fern, George R.; Silver, Jack

    2015-10-15

    Cathodoluminescence (CL) studies are reported on phosphors in a field emission scanning electron microscope (FESEM). ZnO: Zn and other luminescent powders manifest a bright ring around the periphery of the particles: this ring enhances the contrast. Additionally, particles resting on top of others are substantially brighter than underlying ones. These phenomena are explained in terms of the combined effects of electrons backscattered out of the particles, together with light absorption by the substrate. The contrast is found to be a function of the particle size and the energy of the primary electrons. Some phosphor materials exhibit a pronounced comet-like structure at high scan rates in a CL-image, because the particle continues to emit light after the electron beam has moved to a position without phosphor material. Image analysis has been used to study the loss of brightness along the tail and hence to determine the decay time of the materials. The effect of phosphor saturation on the determination of decay times by CL-microscopy was also investigated. - Highlights: • Contrast enhancement are observed in secondary electron and cathodoluminescent images of phosphor particles sitting on top of others. • Backscattered electrons largely explain the observed contrast enhancement. • After glow effects in CL-micrographs of phosphors enable the determination of decay times. • Phosphor saturation can be used to determine the decay time of individual spectral transitions.

  16. A mirror for lab-based quasi-monochromatic parallel x-rays.

    Science.gov (United States)

    Nguyen, Thanhhai; Lu, Xun; Lee, Chang Jun; Jung, Jin-Ho; Jin, Gye-Hwan; Kim, Sung Youb; Jeon, Insu

    2014-09-01

    A multilayered parabolic mirror with six W/Al bilayers was designed and fabricated to generate monochromatic parallel x-rays using a lab-based x-ray source. Using this mirror, curved bright bands were obtained in x-ray images as reflected x-rays. The parallelism of the reflected x-rays was investigated using the shape of the bands. The intensity and monochromatic characteristics of the reflected x-rays were evaluated through measurements of the x-ray spectra in the band. High intensity, nearly monochromatic, and parallel x-rays, which can be used for high resolution x-ray microscopes and local radiation therapy systems, were obtained.

  17. A mirror for lab-based quasi-monochromatic parallel x-rays

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Thanhhai; Lu, Xun; Lee, Chang Jun; Jeon, Insu, E-mail: i-jeon@chonnam.ac.kr [School of Mechanical Engineering, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757 (Korea, Republic of); Jung, Jin-Ho [Pro-optics Co., Ltd., 475 Ami-ri, Bubal-eup, Icheon 467-866 (Korea, Republic of); Jin, Gye-Hwan [Department of Radiology, Nambu University, 76 Chumdan Jungang 1-ro, Gwangsan-gu, Gwangju 506-706 (Korea, Republic of); Kim, Sung Youb [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology, 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of)

    2014-09-15

    A multilayered parabolic mirror with six W/Al bilayers was designed and fabricated to generate monochromatic parallel x-rays using a lab-based x-ray source. Using this mirror, curved bright bands were obtained in x-ray images as reflected x-rays. The parallelism of the reflected x-rays was investigated using the shape of the bands. The intensity and monochromatic characteristics of the reflected x-rays were evaluated through measurements of the x-ray spectra in the band. High intensity, nearly monochromatic, and parallel x-rays, which can be used for high resolution x-ray microscopes and local radiation therapy systems, were obtained.

  18. Fabrication and Cathodoluminescence Spectroscopy of Optical Nanostructures

    Science.gov (United States)

    Redinbo, Gregory Finley

    1995-01-01

    This thesis presents the fabrication of buried optical nanostructures in III-V materials by modifying semiconductor quantum wells using an implantation enhanced interdiffusion (IEI) technique. An investigation of the effect of fabrication parameters on the resulting nanostructures is carried out, and the characteristics of the fabricated structures are measured using room temperature and low temperature cathodoluminescence (CL). IEI using protons is reported for the first time in this work and is found to increase the diffusion length of Al in GaAs/AlGaAs single quantum wells. The enhanced diffusion lengths compare favorably to Ga^ {+} IEI studies and the enhanced interdiffusion mechanism is determined to be due to implantation generated point defects. The use of H^{+} IEI for laterally patterning 100-nm optical nanostructures is demonstrated and is found to be limited by the lateral straggle of the light ions during implantation. Optical quantum wires with widths down to 40 nm are fabricated using low energy Ga^{+ } and electron beam lithography generated metal masks on GaAs/AlGaAs quantum wells. Single nanostructures are measured with low temperature CL, and an increasing blue shift of wire emission with decreasing mask size is measured. The lateral extent of intermixing is found to be 30 nm, independent of Ga^{+} implantation energy. Based on a model of emission energy shift, a lateral quantization energy of ~3 meV for carriers is achieved in these structures. Optical nanostructures are also fabricated with direct write IEI using a Ga^{+ } focused ion beam (FIB) and are compared to the quantum wires. A larger effective lateral extent of intermixing of 200 nm is found with the FIB. IEI patterning of strained InGaAs/GaAs quantum wells is demonstrated and a model of the resulting lateral bandgap profile leads to a lateral defect diffusion length of ~1 mum. Strain enhanced lateral diffusion of defects during IEI cause this length to be substantially larger than that

  19. Breast tomosynthesis with monochromatic beams: a feasibility study using Monte Carlo simulations

    Science.gov (United States)

    Malliori, A.; Bliznakova, K.; Sechopoulos, I.; Kamarianakis, Z.; Fei, B.; Pallikarakis, N.

    2014-08-01

    The aim of this study is to investigate the impact on image quality of using monochromatic beams for lower dose breast tomosynthesis (BT). For this purpose, modeling and simulation of BT and mammography imaging processes have been performed using two x-ray beams: one at 28 kVp and a monochromatic one at 19 keV at different entrance surface air kerma ranging between 0.16 and 5.5 mGy. Two 4 cm thick computational breast models, in a compressed state, were used: one simple homogeneous and one heterogeneous based on CT breast images, with compositions of 50% glandular-50% adipose and 40% glandular-60% adipose tissues by weight, respectively. Modeled lesions, representing masses and calcifications, were inserted within these breast phantoms. X-ray transport in the breast models was simulated with previously developed and validated Monte Carlo application. Results showed that, for the same incident photon fluence, the use of the monochromatic beam in BT resulted in higher image quality compared to the one using polychromatic acquisition, especially in terms of contrast. For the homogenous phantom, the improvement ranged between 15% and 22% for calcifications and masses, respectively, while for the heterogeneous one this improvement was in the order of 33% for the masses and 17% for the calcifications. For different exposures, comparable image quality in terms of signal-difference-to-noise ratio and higher contrast for all features was obtained when using a monochromatic 19 keV beam at a lower mean glandular dose, compared to the polychromatic one. Monochromatic images also provide better detail and, in combination with BT, can lead to substantial improvement in visualization of features, and particularly better edge detection of low-contrast masses.

  20. Diamonds in meteorites – Raman mapping and cathodoluminescence studies

    Directory of Open Access Journals (Sweden)

    A.T. Karczemska

    2010-11-01

    Full Text Available diversity among the diversity of other extraterrestrial carbon phases. The main subject of research shown here are example meteorites consisting diamonds: ureilites DaG 868 and Dho 3013. Results are compared with previous investigations. Diamonds exist in many different meteorites, interplanetary dust particles (IDPs and in comets dust. Origin of different diamonds is still debated among the scientists, two main possibilities are taken into consideration CVD process or shock metamorphism. Understanding laboratory techniques of manufacturing diamond helps in understanding the processes taking place in the Space. From the other side, the new findings and discoveries give the new insight to material science and laboratory techniques.Design/methodology/approach: The samples were examined with different methods, the most investigations presented here are Raman Mapping and Cathodoluminescence (CL.Findings: Diamonds have been found in different samples with different shock stages. It means that not all diamonds in urelites could have shock origin. Diamonds from examined samples show high diversity, they exist in different sizes, from nanodiamonds to micrometer sizes diamonds and in different polytypes. Shifts of Raman diamond peaks indicates this.Research limitations/implications: Results show the possibilities of creating the new diamond-based materials similar to those found in meteorites. Diamond polytypes are not well characterized yet and could give some surprises for materials science. For future research it would be interesting to apply more methods such as X-ray diffraction or HRTEM.Originality/value: SEM+BSE+EDS+CL results and Raman imaging results of DaG 868 and Dho 1303 ureilites are shown for the first time.

  1. High-resolution photocurrent microscopy using near-field cathodoluminescence of quantum dots

    Directory of Open Access Journals (Sweden)

    Heayoung P. Yoon

    2013-06-01

    Full Text Available We report a fast, versatile photocurrent imaging technique to visualize the local photo response of solar energy devices and optoelectronics using near-field cathodoluminescence (CL from a homogeneous quantum dot layer. This approach is quantitatively compared with direct measurements of high-resolution Electron Beam Induced Current (EBIC using a thin film solar cell (n-CdS / p-CdTe. Qualitatively, the observed image contrast is similar, showing strong enhancement of the carrier collection efficiency at the p-n junction and near the grain boundaries. The spatial resolution of the new technique, termed Q-EBIC (EBIC using quantum dots, is determined by the absorption depth of photons. The results demonstrate a new method for high-resolution, sub-wavelength photocurrent imaging measurement relevant for a wide range of applications.

  2. In-situ analysis of optoelectronic properties of twin boundaries in AlGaAs by polarized cathodoluminescence spectroscopy in a TEM.

    Science.gov (United States)

    Ohno, Yutaka

    2010-08-01

    Optoelectronic properties of nanoscale twin boundaries (TBs) in indirect-gap AlGaAs layers were studied by polarized cathodoluminescence spectroscopy in a transmission electron microscope. TBs arranged orderly in a short range, i.e. four or more parallel TBs arranged at regular intervals of nanometre length, emitted an intense monochromatic light polarized parallel to the boundaries. The intensity and the photon energy of the light were examined at different temperatures with different electron fluxes, and the origin of the light was discussed based on a twinning superlattice model. According to the study, it was suggested that the photon energy is tunable by controlling the intervals of TBs, without changing the crystal structure and the composition.

  3. Status report on the tunable monochromatic gamma—ray source

    Institute of Scientific and Technical Information of China (English)

    M.Bertschy; W.Mondelaers; 等

    1996-01-01

    The tunable monochromatic gamma-ray source at the Ghent 15MeV linac is described.The characteristics of the monochromatic beam are given,and some applications,as the detection of heavy elements in other materials,are presented.

  4. Correction: β-Sialon nanowires, nanobelts and hierarchical nanostructures: morphology control, growth mechanism and cathodoluminescence properties

    Science.gov (United States)

    Huang, Juntong; Huang, Zhaohui; Liu, Yangai; Fang, Minghao; Chen, Kai; Huang, Yaoting; Huang, Saifang; Ji, Haipeng; Yang, Jingzhou; Wu, Xiaowen; Zhang, Shaowei

    2016-07-01

    Correction for `β-Sialon nanowires, nanobelts and hierarchical nanostructures: morphology control, growth mechanism and cathodoluminescence properties' by Juntong Huang, et al., Nanoscale, 2014, 6, 424-432.

  5. Optical Defect in GaN-Based Laser Diodes Detected by Cathodoluminescence

    Institute of Scientific and Technical Information of China (English)

    ZHAO Lu-Bing; WU Jie-Jun; XU Ke; BAO Sui; YANG Zhi-Jian; PAN Yao-Bo; HU Xiao-Dong; ZHANG Guo-Yi

    2008-01-01

    @@ GaN-based laser diodes (LDs) with 399 nm wavelength are grown on sapphire substrates by metal organic chemical vapour deposition (MOCVD).Electroluminescence spectra of the fabricated LDs show that the LDs from some grown wafers failed to emit laser.The SEM and XRD results show the similar surface morphology and interface qualities of multi quantum wells (MQWs) and super-lattices between LDs that succeed and fail to emit laser.However, the cathodoluminescence (CL) measurements reveal a kind of optical defect rather than structural defect in un-emitted LDs.Further depth-dependent CL imaging observation indicates that such optical defects originate from the MQWs to the surface of LDs as a non-irradiative recombination centre that should cause the failure of laser emitting of LDs.

  6. Dislocation related droop in InGaN/GaN light emitting diodes investigated via cathodoluminescence

    Science.gov (United States)

    Pozina, Galia; Ciechonski, Rafal; Bi, Zhaoxia; Samuelson, Lars; Monemar, Bo

    2015-12-01

    Today's energy saving solutions for general illumination rely on efficient white light emitting diodes (LEDs). However, the output efficiency droop experienced in InGaN based LEDs with increasing current injection is a serious limitation factor for future development of bright white LEDs. We show using cathodoluminescence (CL) spatial mapping at different electron beam currents that threading dislocations are active as nonradiative recombination centers only at high injection conditions. At low current, the dislocations are inactive in carrier recombination due to local potentials, but these potentials are screened by carriers at higher injection levels. In CL images, this corresponds to the increase of the dark contrast around dislocations with the injection (excitation) density and can be linked with droop related to the threading dislocations. Our data indicate that reduction of droop in the future efficient white LED can be achieved via a drastic reduction of the dislocation density by using, for example, bulk native substrates.

  7. High-Q band edge mode of plasmonic crystals studied by cathodoluminescence

    Science.gov (United States)

    Honda, Masahiro; Yamamoto, Naoki

    2014-02-01

    We have investigated the quality factor (Q-factor) of the band edge modes in the plasmonic crystal by a cathodoluminescence technique. We have found that the Q-factor at the Γ point depends on the terrace width (D)/period (P) ratio of the plasmonic crystal. The finite-difference time-domain methods predict that the band edge mode at D/P = 3/4 has a high-Q-factor (Q ˜ 250 by Palik's permittivity data and Q ˜ 530 by Johnson and Christy's data). The beam-scan spectral images allowed us to visualize the standing surface plasmon polariton waves at the band edge energies, and a high-Q-factor of ˜200 was observed at D/P ˜ 3/4.

  8. High-Q band edge mode of plasmonic crystals studied by cathodoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Masahiro; Yamamoto, Naoki, E-mail: nyamamot@phys.titech.ac.jp [Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551 (Japan)

    2014-02-24

    We have investigated the quality factor (Q-factor) of the band edge modes in the plasmonic crystal by a cathodoluminescence technique. We have found that the Q-factor at the Γ point depends on the terrace width (D)/period (P) ratio of the plasmonic crystal. The finite-difference time-domain methods predict that the band edge mode at D/P = 3/4 has a high-Q-factor (Q ∼ 250 by Palik's permittivity data and Q ∼ 530 by Johnson and Christy's data). The beam-scan spectral images allowed us to visualize the standing surface plasmon polariton waves at the band edge energies, and a high-Q-factor of ∼200 was observed at D/P ∼ 3/4.

  9. Dislocation related droop in InGaN/GaN light emitting diodes investigated via cathodoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Pozina, Galia [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Ciechonski, Rafal [GLO AB, Scheelevägen 22, SE-22363 Lund (Sweden); Bi, Zhaoxia [Solid State Physics, Lund University, Box 118, SE-22100 Lund (Sweden); Samuelson, Lars [GLO AB, Scheelevägen 22, SE-22363 Lund (Sweden); Solid State Physics, Lund University, Box 118, SE-22100 Lund (Sweden); Monemar, Bo [Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping (Sweden); Solid State Physics, Lund University, Box 118, SE-22100 Lund (Sweden); TokyoUniversity of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)

    2015-12-21

    Today's energy saving solutions for general illumination rely on efficient white light emitting diodes (LEDs). However, the output efficiency droop experienced in InGaN based LEDs with increasing current injection is a serious limitation factor for future development of bright white LEDs. We show using cathodoluminescence (CL) spatial mapping at different electron beam currents that threading dislocations are active as nonradiative recombination centers only at high injection conditions. At low current, the dislocations are inactive in carrier recombination due to local potentials, but these potentials are screened by carriers at higher injection levels. In CL images, this corresponds to the increase of the dark contrast around dislocations with the injection (excitation) density and can be linked with droop related to the threading dislocations. Our data indicate that reduction of droop in the future efficient white LED can be achieved via a drastic reduction of the dislocation density by using, for example, bulk native substrates.

  10. Simultaneous cathodoluminescence and electron microscopy cytometry of cellular vesicles labeled with fluorescent nanodiamonds.

    Science.gov (United States)

    Nagarajan, Sounderya; Pioche-Durieu, Catherine; Tizei, Luiz H G; Fang, Chia-Yi; Bertrand, Jean-Rémi; Le Cam, Eric; Chang, Huan-Cheng; Treussart, François; Kociak, Mathieu

    2016-06-02

    Light and Transmission Electron Microscopies (LM and TEM) hold potential in bioimaging owing to the advantages of fast imaging of multiple cells with LM and ultrastructure resolution offered by TEM. Integrated or correlated LM and TEM are the current approaches to combine the advantages of both techniques. Here we propose an alternative in which the electron beam of a scanning TEM (STEM) is used to excite concomitantly the luminescence of nanoparticle labels (a process known as cathodoluminescence, CL), and image the cell ultrastructure. This CL-STEM imaging allows obtaining luminescence spectra and imaging ultrastructure simultaneously. We present a proof of principle experiment, showing the potential of this technique in image cytometry of cell vesicular components. To label the vesicles we used fluorescent diamond nanocrystals (nanodiamonds, NDs) of size ≈150 nm coated with different cationic polymers, known to trigger different internalization pathways. Each polymer was associated with a type of ND with a different emission spectrum. With CL-STEM, for each individual vesicle, we were able to measure (i) their size with nanometric resolution, (ii) their content in different ND labels, and realize intracellular component cytometry. In contrast to the recently reported organelle flow cytometry technique that requires cell sonication, CL-STEM-based image cytometry preserves the cell integrity and provides a much higher resolution in size. Although this novel approach is still limited by a low throughput, the automatization of data acquisition and image analysis, combined with improved intracellular targeting, should facilitate applications in cell biology at the subcellular level.

  11. Native point defect formation in flash sintered ZnO studied by depth-resolved cathodoluminescence spectroscopy

    Science.gov (United States)

    Gao, Hantian; Asel, Thaddeus J.; Cox, Jon W.; Zhang, Yuanyao; Luo, Jian; Brillson, L. J.

    2016-09-01

    Depth-resolved cathodoluminescence spectroscopy studies of flash sintered ZnO reveal that thermal runaway induces the formation of native point defects inside individual grains. Defects associated with oxygen vacancies (VO) form preferentially, contributing additional donors that increase conductivity within the grains of the polycrystalline material. Hyperspectral imaging of the granular cross sections shows filaments of increased VO following thermal runaway between the capacitor anode and cathode, supporting a heating mechanism localized on a granular scale. Within the grains, these defects form preferentially inside rather than at their boundaries, further localizing the dominant heating mechanism.

  12. Cathodoluminescence study of thin films of high Tc superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Barkay, Z.; Azoulay, J.; Lereah, Y.; Dai, U.; Hess, N.; Racah, D.; Gruenbaum, E.; Deutscher, G. (School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 69978 Ramat Aviv (Israel))

    1990-10-22

    Cathodoluminescence (CL) of thin films of high {ital T}{sub {ital c}} superconductors was studied in the scanning electron microscope. The depth and the lateral locations of the different phases can be revealed. In thin films, unlike the bulk superconductors, the CL information can be obtained either from the film itself or the substrate by varying the primary beam energy. At high beam energy, substrate defects and slight thickness variations of a single high {ital T}{sub {ital c}} phase are observed. The resolution of the CL measurements improves at low temperatures.

  13. Study on paper moisture measurement method by monochromatic light sources

    Science.gov (United States)

    Mo, Changtao; Du, Xin; He, Ping; Zhang, Lili; Li, Nan; Wang, Ming

    2010-10-01

    We design the emission and detection optical paths of three monochromatic infrared light sources with different wavelength. The three light sources are placed according to the different angles, so that the three kinds of monochromatic lights are converged on the same point of the sample. Using the method, we can detect the same point and improve the measurement accuracy. We choose the standard near-infrared monochromatic light source, so that we can save some equipments, such as tungsten- halogen lamp, filtered wheel, collimation focalizer, electric machine, and so on. In particular, we save the cumbersome cooling system, reduce the volume of the instrument greatly and reduce the cost. The three monochromatic light sources are supplied by the same pulse power source, to ensure their synchronous working.

  14. Relief Restoration of Complicated form Objects by Monochromatic Microwave Radiation

    Directory of Open Access Journals (Sweden)

    Kuzmenko Ivan

    2016-01-01

    Full Text Available Article demonstrates possibility of monochromatic radiation usage for relief restoration. There is a problem with restoration when scanned object is not flat and it is not parallel to the scanning plane. It was discovered that two-dimensional phase distribution could be applied for distance determination. It is reliable way to solve problems listed above. In conclusion offered methods allow monochromatic microwave radiation usage for screening system development.

  15. Dual-energy tissue cancellation in mammography with quasi-monochromatic x-rays.

    Science.gov (United States)

    Marziani, M; Taibi, A; Tuffanelli, A; Gambaccini, M

    2002-01-21

    Dual-energy radiography has not evolved into a routine clinical examination yet due to intrinsic limitations of both dual-kVp imaging and single-exposure imaging with conventional x-ray sources. The recent introduction of novel quasi-monochromatic x-ray sources and detectors could lead to interesting improvements, especially in mammography where the complex structure of healthy tissues often masks the detectability of lesions. A dual-energy radiography technique based on a tissue cancellation algorithm has been developed for mammography, with the aim of maximizing the low intrinsic contrast of pathologic tissues while being able to minimize or cancel the contrast between glandular and fat tissues. Several images of a plastic test object containing various tissue equivalent inserts were acquired in the energy range 17-36 keV using a quasi-monochromatic x-ray source and a scintillator-coated CCD detector. Images acquired at high and low energies were nonlinearly combined to generate two energy-independent basis images. Suitable linear combinations of these two basis images result in the elimination of the contrast of a given material with respect to another. This makes it possible to selectively cancel certain details in the processed image.

  16. Photomosaics of the cathodoluminescence of 60 sections of meteorites and lunar samples

    Science.gov (United States)

    Akridge, D.G.; Akridge, J.M.C.; Batchelor, J.D.; Benoit, P.H.; Brewer, J.; DeHart, J.M.; Keck, B.D.; Jie, L.; Meier, A.; Penrose, M.; Schneider, D.M.; Sears, D.W.G.; Symes, S.J.K.; Yanhong, Z.

    2004-01-01

    Cathodoluminescence (CL) petrography provides a means of observing petrographic and compositional properties of geological samples not readily observable by other techniques. We report the low-magnification CL images of 60 sections of extraterrestrial materials. The images we report include ordinary chondrites (including type 3 ordinary chondrites and gas-rich regolith breccias), enstatite chondrites, CO chondrites and a CM chondrite, eucrites and a howardite, lunar highland regolith breccias, and lunar soils. The CL images show how primitive materials respond to parent body metamorphism, how the metamorphic history of EL chondrites differs from that of EH chondrites, how dark matrix and light clasts of regolith breccias relate to each other, how metamorphism affects eucrites, the texture of lunar regolith breccias and the distribution of crystallized lunar spherules ("lunar chondrules"), and how regolith working affects the mineral properties of lunar soils. More particularly, we argue that such images are a rich source of new information on the nature and history of these materials and that our efforts to date are a small fraction of what can be done. Copyright 2004 by the American Geophysical Union.

  17. Determining contrast sensitivity functions for monochromatic light emitted by high-brightness LEDs

    Science.gov (United States)

    Ramamurthy, Vasudha; Narendran, Nadarajah; Freyssinier, Jean Paul; Raghavan, Ramesh; Boyce, Peter

    2004-01-01

    Light-emitting diode (LED) technology is becoming the choice for many lighting applications that require monochromatic light. However, one potential problem with LED-based lighting systems is uneven luminance patterns. Having a uniform luminance distribution is more important in some applications. One example where LEDs are becoming a viable alternative and luminance uniformity is an important criterion is backlighted monochromatic signage. The question is how much uniformity is required for these applications. Presently, there is no accepted metric that quantifies luminance uniformity. A recent publication proposed a method based on digital image analysis to quantify beam quality of reflectorized halogen lamps. To be able to employ such a technique to analyze colored beams generated by LED systems, it is necessary to have contrast sensitivity functions (CSFs) for monochromatic light produced by LEDs. Several factors including the luminance, visual field size, and spectral power distribution of the light affect the CSFs. Although CSFs exist for a variety of light sources at visual fields ranging from 2 degrees to 20 degrees, CSFs do not exist for red, green, and blue light produced by high-brightness LEDs at 2-degree and 10-degree visual fields and at luminances typical for backlighted signage. Therefore, the goal of the study was to develop a family of CSFs for 2-degree and 10-degree visual fields illuminated by narrow-band LEDs at typical luminances seen in backlighted signs. The details of the experiment and the results are presented in this manuscript.

  18. Cathodoluminescent properties of Tb3+-doped yttria nanocrystallites

    Institute of Scientific and Technical Information of China (English)

    P.Psuja; D.Hreniak; W.Str(e)k

    2009-01-01

    The Tb3+-doped Y2O3 nanopowders were synthesized using the modified Pechini method.The average size of nanocrystallites was controlled by different sintering temperatures.The structure and morphology of obtained nanopowders were examined using the XRD and SEM analyses.The Cr:Al2O3 was mixed with Tb3+:Y2O3 powders and its normalized emission was used.to measure a relative intensity of Tb3+:Y2O3.The mixtures were electrophorefically deposited on ITO-glass slides.The cathodoluminescence spectra of obtained layers were recorded and analysed.The discussion over an influence of average grains size on phosphor efficiency was presented.

  19. Cathodoluminescence and Magnetic Properties of Mn+ Implanted AIN

    Institute of Scientific and Technical Information of China (English)

    LI Ming-Kai; LI Cheng-Bin; LIU Chuan-Sheng; FAN Xiang-Jun; FU De-Jun; SHON Yun; KANG Tae-Won

    2004-01-01

    @@ The Ⅲ-Ⅴ wide band gap semiconductors show the potential in applications for dilute magnetic semiconductors.AlN films are implanted with 20-keV Mn+ ions with a dose of 5 × 1016cm-2. The cross section of as-implanted AlN are investigated by field-emission scanning electron microscopy and the energy dispersive spectra. The result confirms that the implantation depth is about 100nm. Cathodoluminescence measurements show the main peak at 2.6eV attributed to a donor-to-Mn2+ transition. It is argued that the Mn element in AlN can act as a p-type dopant peak at 2.07eV. The magnetic measurement shows a transition temperature of 100K in the implanted AlN annealed at 500℃ for 30min. Clear ferromagnetic hysteresis was observed at 77K, with a coercive field of 212.7Oe.

  20. Azimuthally polarized cathodoluminescence from InP nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Brenny, B. J. M.; Osorio, C. I.; Polman, A., E-mail: polman@amolf.nl [Center for Nanophotonics, FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam (Netherlands); Dam, D. van [COBRA Research Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Gómez Rivas, J. [COBRA Research Institute, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); FOM Institute DIFFER, P.O. Box 6336, 5600 HH Eindhoven (Netherlands)

    2015-11-16

    We determine the angle and polarization dependent emission from 1.75 µm and 2.50 µm long InP nanowires by using cathodoluminescence polarimetry. We excite the vertical wires using a 5 keV electron beam, and find that the 880 nm bandgap emission shows azimuthally polarized rings, with the number of rings depending on the wire height. The data agree well with a model in which spontaneous emission from the wire emitted into the far field interferes with emission reflected off the substrate. From the model, the depth range from which the emission is generated is found to be up to 400 nm below the top surface of the wires, well beyond the extent of the primary electron cloud. This enables a probe of the carrier diffusion length in the InP nanowires.

  1. Simultaneous cathodoluminescence and electron microscopy cytometry of cellular vesicles labeled with fluorescent nanodiamonds

    Science.gov (United States)

    Nagarajan, Sounderya; Pioche-Durieu, Catherine; Tizei, Luiz H. G.; Fang, Chia-Yi; Bertrand, Jean-Rémi; Le Cam, Eric; Chang, Huan-Cheng; Treussart, François; Kociak, Mathieu

    2016-06-01

    Light and Transmission Electron Microscopies (LM and TEM) hold potential in bioimaging owing to the advantages of fast imaging of multiple cells with LM and ultrastructure resolution offered by TEM. Integrated or correlated LM and TEM are the current approaches to combine the advantages of both techniques. Here we propose an alternative in which the electron beam of a scanning TEM (STEM) is used to excite concomitantly the luminescence of nanoparticle labels (a process known as cathodoluminescence, CL), and image the cell ultrastructure. This CL-STEM imaging allows obtaining luminescence spectra and imaging ultrastructure simultaneously. We present a proof of principle experiment, showing the potential of this technique in image cytometry of cell vesicular components. To label the vesicles we used fluorescent diamond nanocrystals (nanodiamonds, NDs) of size ~150 nm coated with different cationic polymers, known to trigger different internalization pathways. Each polymer was associated with a type of ND with a different emission spectrum. With CL-STEM, for each individual vesicle, we were able to measure (i) their size with nanometric resolution, (ii) their content in different ND labels, and realize intracellular component cytometry. In contrast to the recently reported organelle flow cytometry technique that requires cell sonication, CL-STEM-based image cytometry preserves the cell integrity and provides a much higher resolution in size. Although this novel approach is still limited by a low throughput, the automatization of data acquisition and image analysis, combined with improved intracellular targeting, should facilitate applications in cell biology at the subcellular level.Light and Transmission Electron Microscopies (LM and TEM) hold potential in bioimaging owing to the advantages of fast imaging of multiple cells with LM and ultrastructure resolution offered by TEM. Integrated or correlated LM and TEM are the current approaches to combine the advantages of

  2. Cathodoluminescence investigations on quartz cement in sandstones of Khabour Formation from Iraqi Kurdistan region, northern Iraq

    DEFF Research Database (Denmark)

    Omer, Muhamed Fakhri; Friis, Henrik

    The Ordovician deltaic to shallow marine Khabour Formation in Northern Iraq consists mainly of sandstone with minor siltstone and interbedded shale. The sandstones are pervasively cemented by quartz that resulted in very little preserved primary porosity. Cathodoluminescence and petrographic stud...

  3. Display of the complex degree of coherence due to quasi-monochromatic spatially incoherent sources.

    Science.gov (United States)

    Michalski, M; Sicre, E E; Rabal, H J

    1985-12-01

    A method for displaying the complex degree of coherence (CDC) of a quasi-monochromatic spatially incoherent source is proposed. The phase of the CDC is encoded in a method similar to that used in interferometric imaging with incoherent light. The method is based on Fourier analysis of the speckle pattern that appears when a diffuser is illuminated with the partially coherent field whose CDC is to be displayed. In addition, an intensity pattern that resembles the spatial distribution of the incoherent source can also be obtained.

  4. Statistical analysis of ocular monochromatic aberrations in Chinese population for adaptive optics ophthalmoscope design

    Directory of Open Access Journals (Sweden)

    Junlei Zhao

    2017-01-01

    Full Text Available It is necessary to know the distribution of the Chinese eye’s aberrations in clinical environment to guide high-resolution retinal imaging system design for large Chinese population application. We collected the monochromatic wave aberration of 332 healthy eyes and 344 diseased eyes in Chinese population across a 6.0-mm pupil. The aberration statistics of Chinese eyes including healthy eyes and diseased eyes were analyzed, and some differences of aberrations between the Chinese and European race were concluded. On this basis, the requirement for adaptive optics (AO correction of the Chinese eye’s monochromatic aberrations was analyzed. The result showed that a stroke of 20μm and ability to correct aberrations up to the 8th Zernike order were needed for reflective wavefront correctors to achieve near diffraction-limited imaging in both groups for a reference wavelength of 550nm and a pupil diameter of 6.0mm. To verify the analysis mentioned above, an AO flood-illumination system was established, and high-resolution retinal imaging in vivo was achieved for Chinese eye including both healthy and diseased eyes.

  5. On monochromatic arm exponents for 2D critical percolation

    CERN Document Server

    Beffara, Vincent

    2009-01-01

    We investigate the so-called monochromatic arm exponents for critical percolation in two dimensions. These exponents, describing the probability of observing j disjoint macroscopic paths, are shown to exist and to form a different family from the (now well-understood) polychromatic exponents.

  6. Kernels by Monochromatic Paths and Color-Perfect Digraphs

    Directory of Open Access Journals (Sweden)

    Galeana-Śanchez Hortensia

    2016-05-01

    Full Text Available For a digraph D, V (D and A(D will denote the sets of vertices and arcs of D respectively. In an arc-colored digraph, a subset K of V(D is said to be kernel by monochromatic paths (mp-kernel if (1 for any two different vertices x, y in N there is no monochromatic directed path between them (N is mp-independent and (2 for each vertex u in V (D \\ N there exists v ∈ N such that there is a monochromatic directed path from u to v in D (N is mp-absorbent. If every arc in D has a different color, then a kernel by monochromatic paths is said to be a kernel. Two associated digraphs to an arc-colored digraph are the closure and the color-class digraph CC(D. In this paper we will approach an mp-kernel via the closure of induced subdigraphs of D which have the property of having few colors in their arcs with respect to D. We will introduce the concept of color-perfect digraph and we are going to prove that if D is an arc-colored digraph such that D is a quasi color-perfect digraph and CC(D is not strong, then D has an mp-kernel. Previous interesting results are generalized, as for example Richardson′s Theorem.

  7. Classical stabilization of the hydrogen atom in a monochromatic field

    Energy Technology Data Exchange (ETDEWEB)

    Benvenuto, F.; Casati, G. (Dipartimento di Fisica dell' Universita, Via Castelnuovo 7, 22100 Como (Italy)); Shepelyansky, D.L. (Laboratoire de Physique Quantique, Universite Paul Sabatier, 31062, Toulouse (France))

    1993-02-01

    We report the results of analytical and numerical investigations on the ionization of a classical atom in a strong, linearly polarized, monochromatic field. We show that the ionization probability decreases with increasing field intensity at field amplitudes much larger than the classical chaos border. This effect should be observable in real laboratory experiments.

  8. New Developments in Cathodoluminescence Spectroscopy for the Study of Luminescent Materials

    Directory of Open Access Journals (Sweden)

    Daniel den Engelsen

    2017-03-01

    Full Text Available Herein, we describe three advanced techniques for cathodoluminescence (CL spectroscopy that have recently been developed in our laboratories. The first is a new method to accurately determine the CL-efficiency of thin layers of phosphor powders. When a wide band phosphor with a band gap (Eg > 5 eV is bombarded with electrons, charging of the phosphor particles will occur, which eventually leads to erroneous results in the determination of the luminous efficacy. To overcome this problem of charging, a comparison method has been developed, which enables accurate measurement of the current density of the electron beam. The study of CL from phosphor specimens in a scanning electron microscope (SEM is the second subject to be treated. A detailed description of a measuring method to determine the overall decay time of single phosphor crystals in a SEM without beam blanking is presented. The third technique is based on the unique combination of microscopy and spectrometry in the transmission electron microscope (TEM of Brunel University London (UK. This combination enables the recording of CL-spectra of nanometre-sized specimens and determining spatial variations in CL emission across individual particles by superimposing the scanning TEM and CL-images.

  9. Spatially Resolved Cathodoluminescence of CdTe Thin Films and Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Romero, M. J.; Metzger, W.; Gessert, T. A.; Albin, D. S.; Al-Jassim, M. M.

    2003-05-01

    We have investigated the spatial distribution of different transitions identified in the emission spectra of CdTe thin films and solar cells by cathodoluminescence spectroscopic imaging (CLSI). Prior to back-contact deposition, the spectra are dominated by excitons (X) and donor-to-acceptor (DAP) transitions. After contacting, Cu acceptor states are found in addition to the X and DAP recombination processes. A very systematic behavior found in CdTe is that DAP transitions occur preferentially at grain boundaries (GBs). The distribution of these states responsible for the passivation of GBs is not affected by further processing, although additional levels participate in the recombination process. We believe that this stability is one of the reasons for the success of thin-film CdTe solar cells. Estimates of the densities of different donors and acceptors participating in the recombination process are possible from the analysis of the evolution of the emission spectra with the excitation level. It is found that the back contact suppresses some intrinsic acceptors (associated with the A center) near the back-contact interface and, therefore, Cu acceptor states should be responsible for the p-typeness of the back surface more than a reduction of compensation. CLSI measurements are shown to be helpful in understanding the physics of back-contact formation.

  10. Cathodoluminescence Emission Studies for Selected Phosphor-Based Sensor Materials

    Energy Technology Data Exchange (ETDEWEB)

    Goedeke, Shawn [ORNL; Hollerman, William Andrew [ORNL; Allison, Stephen W [ORNL; Gray, P A [Integrated Concepts and Research Corporation - Huntsville, AL; Lewis, Linda A [ORNL; Smithwick III, Robert W [ORNL; Boatner, Lynn A [ORNL; Glasgow, David C [ORNL; Ivanov, Ilia N [ORNL; Wise, H. [Integrated Concepts and Research Corporation - Huntsville, AL

    2005-01-01

    The current interest in returning to the Moon and Mars by 2030 makes cost effective and low mass health monitoring sensors essential for spacecraft development. In space, there are many surface measurements that are required to monitor the condition of the spacecraft including: surface temperature, radiation dose, and impact. Through the use of phosphors, these conditions can be monitored. Practical space-based phosphor sensors will depend heavily upon research investigating the resistance of phosphors to ionizing radiation and the ability to anneal or self-heal from damage caused by ionizing radiation. The cathodoluminescence (CL) testing was performed using the low energy electron system located at the NASA Marshall Space Flight Center (MSFC) in Huntsville, Alabama. For the materials tested, several interesting results were observed. For most materials, increases in both beam energy and current density improved the CL fluorescence yield. It was also noted that YAG:Nd,Ce has the greatest near infrared intensity for any of the tested materials. The evaluation of dopant concentration in YPO{sub 4}:Nd showed minimal differences in spectral shape and intensity. While the total electron dose was small, the intention was to maximize the number of irradiated materials.

  11. Monochromatic computed tomography with a compact laser-driven X-ray source.

    Science.gov (United States)

    Achterhold, K; Bech, M; Schleede, S; Potdevin, G; Ruth, R; Loewen, R; Pfeiffer, F

    2013-01-01

    A laser-driven electron-storage ring can produce nearly monochromatic, tunable X-rays in the keV energy regime by inverse Compton scattering. The small footprint, relative low cost and excellent beam quality provide the prospect for valuable preclinical use in radiography and tomography. The monochromaticity of the beam prevents beam hardening effects that are a serious problem in quantitative determination of absorption coefficients. These values are important e.g. for osteoporosis risk assessment. Here, we report quantitative computed tomography (CT) measurements using a laser-driven compact electron-storage ring X-ray source. The experimental results obtained for quantitative CT measurements on mass absorption coefficients in a phantom sample are compared to results from a rotating anode X-ray tube generator at various peak voltages. The findings confirm that a laser-driven electron-storage ring X-ray source can indeed yield much higher CT image quality, particularly if quantitative aspects of computed tomographic imaging are considered.

  12. How do granites solidify? Information from quantitative textural studies using cathodoluminescence and other techniques

    Science.gov (United States)

    Higgins, Michael

    2017-04-01

    The qualitative and quantitative study of granitic textures (microstructures) has been somewhat neglected, as compared to mafic rocks. Certainly some granite samples are not readily susceptible to textural analysis, particularly if they are altered, but many acidic rocks can be examined in the same way as mafic rocks, using the same techniques. The earliest studies were of K-feldspar megacrysts in granitoids, a component that can be easily quantified by direct measurement in the field and image analysis of stained slabs. However, analysis of thin sections requires other techniques. Although the main components of granites, plagioclase, K-feldspar and quartz, can be readily distinguished in thin section by experienced petrographers, they cannot be quantified readily from optical images using automatic or semi-automatic image analysis methods. An alternative approach is to use cold-cathode cathodoluminescence (CL). This microscope-based method easily distinguishes these three phases and can also identify alteration. Minor colour differences and zonation in CL can sometimes reveal the presence of different crystal populations. Apatite, zircon and other minor phases are also imaged, but all silicate minerals that contain iron do not luminesce. A combination of CL and unpolarised light can be used to classify a thin section into almost all significant phases. In these phase maps adjoining crystals of the same phase are amalgamated. Segmenting the phase maps into crystal maps requires the addition of a cross-polarised image and manual crystal tracing, but provides much richer data. CL images of unaltered granites can reveal a wealth of different textures which will be illustrated with granitoid samples from the Illapel Plutonic suite, Chile and elsewhere. The overall goal is to understand the solidification process. CL was used to select the least altered samples and a mosaic of about half a thin section was produced for each sample. Plagioclase is always the earliest

  13. Origin and Characteristics of Blue Light Emission in Solid State Cathodoluminescence of MEH-PPV

    Institute of Scientific and Technical Information of China (English)

    QU Chong; XU Zheng; TENG Feng; QIAN Lei; YU Wen-Ge; QUAN Shan-Yu; XU Xu-Rong

    2004-01-01

    Based on our previous study [Chin. Phys. Lett. 20 (2003) 1144] on the solid-state cathodoluminescence from organic luminescent materials, here we study the origin and characteristics of blue light emission in solid-state cathodoluminescence of Poly [(2-methoxy-5-(2′-ethyl-hexyloxy)phenylene vinyene] (MEH-PPV) and the dependence of each spectral peak on electric field strength. The results demonstrate that the blue spectral shift benefits from field ionization of excitons, and three regions of electric field are found, in which there are pure exciton emission, coexistence of exciton emission and radiative recombination, and pure radiative recombination.

  14. Can cathodoluminescence of feldspar be used as provenance indicator?

    Science.gov (United States)

    Scholonek, Christiane; Augustsson, Carita

    2016-05-01

    We have studied feldspar from crystalline rocks for its textural and spectral cathodoluminescence (CL) characteristics with the aim to reveal their provenance potential. We analyzed ca. 60 rock samples of plutonic, volcanic, metamorphic, and pegmatitic origin from different continents and of 16 Ma to 2 Ga age for their feldspar CL textures and ca. 1200 feldspar crystals from these rocks for their CL color spectra. Among the analyzed rocks, igneous feldspar is most commonly zoned, whereby oscillatory zoning can be confirmed to be typical for volcanic plagioclase. The volcanic plagioclase also less commonly contains twin lamellae that are visible in CL light than crystals from other rock types. Alkali feldspar, particularly from igneous and pegmatitic rocks, was noted to be most affected by alteration features, visible as dark spots, lines and irregular areas. The size of all textural features of up to ca. 150 μm, in combination with possible alteration in both the source area and the sedimentary system, makes the CL textures of feldspar possible to use for qualitative provenance research only. We observed alkali feldspar mostly to luminesce in a bluish color and sometimes in red, and plagioclase in green to yellow. The corresponding CL spectra are dominated by three apparent intensity peaks at 440-520 nm (mainly blue), 540-620 nm (mainly green) and 680-740 nm (red to infrared). A dominance of the peak in the green wavelength interval over the blue one for plagioclase makes CL particularly useful for the differentiation of plagioclase from alkali feldspar. An apparent peak position in red to infrared at < 710 nm for plagioclase mainly is present in mafic rocks. Present-day coastal sand from Peru containing feldspar with the red to infrared peak position mainly exceeding 725 nm for northern Peruvian sand and a larger variety for sand from southern Peru illustrates a discriminative effect of different source areas. We conclude that the provenance application

  15. Diagenetic history of lower Pliocene rhodoliths of the Azores Archipelago (NE Atlantic): Application of cathodoluminescence techniques.

    Science.gov (United States)

    Rebelo, A C; Meireles, R P; Barbin, V; Neto, A I; Melo, C; Ávila, S P

    2016-01-01

    The diagenetic history of calcareous fossils is required for their application as palaeoenvironmental indicators. In this study, cathodoluminescence-microscopy (CL microscopy) and back scatter electron image-energy dispersive X-ray spectroscopy (BSE-EDS microscopy) were applied to Pliocene rhodoliths from the Azores Archipelago (NE Atlantic) in order to gain additional insight regarding the trace element content distribution throughout the algae thalli, and to ascertain palaeoenvironmental interpretations. Two types of luminescence were obtained: (1) high and (2) low luminescence. Rhodoliths with high luminescence are related with high concentrations of Mn(2+) in seawater and low luminescence rhodoliths are related with low concentrations of Mn(2+) in seawater. When the rhodoliths were deposited at about 4.0-4.5 Ma, the shoreline configuration of Santa Maria Island was much different than today. The influence of volcanic activity due to the extrusion of lavas and associated products and/or the presence of active shallow-water hydrothermal vents, was reflected in the sea water chemistry, with penecontemporaneous palaeoshores of the island featuring a high sea water concentration of Mn(2+), which mirrored on the rhodolith Mn(2+) high concentration. By contrast, rhodoliths located about 2.8 and 2.9 km from the shore, in areas with low seawater Mn(2+) concentration, had low luminescence, reflecting the low Mn(2+) concentration in seawater. Rhodoliths chemical data and the geological history of the island proved to be congruent with the palaeogeographical reconstruction of Santa Maria Island at the time of the formation of the rhodoliths.

  16. Memory effect and cathodoluminescent properties of YAG:Nd3+ nanoceramics

    Science.gov (United States)

    Orekhova, K. N.; Trofimov, A. N.; Zamoryanskaya, M. V.; Stręk, W.

    2016-06-01

    The cathodoluminescent properties of nanoceramics based on neodymium-doped yttrium-aluminum garnet (YAG:Nd3+) are studied in a wide optical spectral range (from UV to IR). It is shown that the spectral positions of the emission bands of nanoceramics are identical to that of single crystal, but the bands of nanoceramics are broadened by no more than 15% from the half bandwidths of single crystal. The intensity of cathodoluminescence bands in nanoceramics is lower, and the lifetimes of radiative levels are shorter. It is found for the first time that electron-beam irradiation of nanoceramics increases the cathodoluminescence intensity of bands in visible and UV ranges (by two or more times). Preliminary electron beam irradiation of YAG:Nd3+ nanoceramics samples leads to the increase of cathodoluminescence efficiency. Such effect retains for a long time (a year and more) and can be compared to the memory effect. This effect is not observed in single crystal. We propose a model describing this effect in nanoceramics.

  17. Trace chemical characterization using monochromatic X-ray undulator radiation

    Science.gov (United States)

    Eba; Numako; Iihara; Sakurai

    2000-06-01

    An efficient Johansson-type X-ray fluorescence spectrometer has been developed for advanced X-ray spectroscopic analysis with third-generation synchrotron radiation. Kalpha and Kbeta X-ray fluorescence spectra for trace metals have been collected by a Ge(220) analyzing crystal with a Rowland radius of 150 mm, under monochromatic X-ray excitation at the undulator beamline at the SPring-8. The energy resolution is approximately 10 eV for most of the K lines for 3d transition metals. In light of the greatly improved efficiency, as well as the excellent signal-to-background ratio, the relative and absolute detection limits achieved are 1 ppm and 1.2 ng of copper in a carbon matrix, respectively. The energy resolution of the present spectrometer permits the observation of some chemical effects in Kbeta spectra. It has been demonstrated that the changes in Kbeta5 and Kbeta'' intensity for iron and cobalt compounds can be used for the analysis of chemical states. Resonant X-ray fluorescent spectra are another important application of monochromatic excitation. In view of trace chemical characterization, the present spectrometer can be a good alternative to a conventional Si(Li) detector system when combined with highly brilliant X-rays.

  18. SU-D-BRA-06: Dual-Energy Chest CT: The Effects of Virtual Monochromatic Reconstructions On Texture Analysis Features

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, J; Duran, C; Stingo, F; Wei, W; Rao, A; Zhang, L; Court, L; Erasmus, J; Godoy, M [UT MD Anderson Cancer Center, Houston, TX (United States)

    2015-06-15

    Purpose: To characterize the effect of virtual monochromatic reconstructions on several commonly used texture analysis features in DECT of the chest. Further, to assess the effect of monochromatic energy levels on the ability of these textural features to identify tissue types. Methods: 20 consecutive patients underwent chest CTs for evaluation of lung nodules using Siemens Somatom Definition Flash DECT. Virtual monochromatic images were constructed at 10keV intervals from 40–190keV. For each patient, an ROI delineated the lesion under investigation, and cylindrical ROI’s were placed within 5 different healthy tissues (blood, fat, muscle, lung, and liver). Several histogram- and Grey Level Cooccurrence Matrix (GLCM)-based texture features were then evaluated in each ROI at each energy level. As a means of validation, these feature values were then used in a random forest classifier to attempt to identify the tissue types present within each ROI. Their predictive accuracy at each energy level was recorded. Results: All textural features changed considerably with virtual monochromatic energy, particularly below 70keV. Most features exhibited a global minimum or maximum around 80keV, and while feature values changed with energy above this, patient ranking was generally unaffected. As expected, blood demonstrated the lowest inter-patient variability, for all features, while lung lesions (encompassing many different pathologies) exhibited the highest. The accuracy of these features in identifying tissues (76% accuracy) was highest at 80keV, but no clear relationship between energy and classification accuracy was found. Two common misclassifications (blood vs liver and muscle vs fat) accounted for the majority (24 of the 28) errors observed. Conclusion: All textural features were highly dependent on virtual monochromatic energy level, especially below 80keV, and were more stable above this energy. However, in a random forest model, these commonly used features were

  19. Cathodoluminescence investigations on quartz cement in the sandstones of Khabour Formation from Iraqi Kurdistan Region, Northern Iraq

    DEFF Research Database (Denmark)

    Omer, Muhamed Fakhri; Friis, Henrik

    2014-01-01

    The Ordovician deltaic to shallow marine Khabour Formation in Northern Iraq consists mainly of sandstone with minor siltstone and interbedded shale. The sandstones are pervasively cemented by quartz that resulted in very little preserved primary porosity. Cathodoluminescence and petrographic stud...

  20. Cathodoluminescence spectroscopy of single GaN/AlN quantum dots directly performed in a scanning transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Bertram, Frank; Schmidt, Gordon; Mueller, Marcus; Petzold, Silke; Veit, Peter; Christen, Juergen [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg (Germany); Das, Aparna; Monroy, Eva [CEA/CNRS Group Nanophysique et Semiconducteurs, INAC/SP2M, CEA-Grenoble (France)

    2013-07-01

    In this study we will present a nanoscale optical and structural characterization of a III-nitride based quantum dot (QD) heterostructure. A 1 μm thick AlN layer grown on a sapphire substrate using metal organic vapor phase epitaxy (MOVPE) serves as template for the further growth process. Subsequent, a stack of 10 GaN QD layers, each embedded in 50 nm thick AlN barrier, were grown under an optimized plasma-assisted molecular beam epitaxy process on an AlN-MOVPE/sapphire template. The cross-section high angle annular dark field image (HAADF) in a scanning transmission electron microscope (STEM) clearly reveals the GaN QD layers. The comparison of the HAADF image with the simultaneously recorded panchromatic cathodoluminescence mapping at 16 K exhibits a spot like luminescence distribution of the upper six QD layers solely, indicating no formation of the first four intentionally grown QD layers. Addressing a very few to single QDs we observe a broad luminescence between 3.0 eV and 4.0 eV originating from the superposition of the single emission lines.

  1. On the detectability of Galactic dark matter annihilation into monochromatic gamma-rays

    Institute of Scientific and Technical Information of China (English)

    唐志成; 袁强; 毕效军; 陈国明

    2011-01-01

    Monochromatic y-rays are thought to be the smoking gun signal for identifying dark matter annihilation. However, the flux of monochromatic y-rays is usually suppressed by virtual quantum effects since dark matter should be neutral and does not couple with

  2. On the detectability of Galactic dark matter annihilation into monochromatic gamma-rays

    Institute of Scientific and Technical Information of China (English)

    TANG Zhi-Cheng; YUAN Qiang; BI Xiao-Jun; CHEN Guo-Ming

    2011-01-01

    Monochromatic γ-rays are thought to be the smoking gun signal for identifying dark matter annihilation. However, the flux of monochromatic γ-rays is usually suppressed by virtual quantum effects since dark matter should be neutral and does not couple with γ-rays directly. In this work, we study the detection strategy of the monochromatic γ-rays in a future space-based detector. The flux of monochromatic γ-rays between 50 GeV and several TeV is calculated by assuming the supersymmetric neutralino as a typical dark matter candidate. The detection both by focusing on the Galactic center and in a scan mode that detects γ-rays from the whole Galactic halo are compared. The detector performance for the purpose of monochromatic γ-ray detection, with different energy and angular resolution, field of view, and background rejection efficiencies, is carefully studied with both analytical and fast Monte-Carlo methods.

  3. On the Detectability of Galactic Dark Matter Annihilation into Monochromatic Gamma-rays

    CERN Document Server

    Tang, Zhi-Cheng; Bi, Xiao-Jun; Chen, Guo-Ming

    2010-01-01

    Monochromatic gamma-rays are thought to be the smoking gun signal for identifying the dark matter annihilation. However, the flux of monochromatic gamma-rays is usually suppressed by the virtual quantum effects since dark matter should be neutral and does not couple with gamma-rays directly. In the work we study the detection strategy of the monochromatic gamma-rays in a future space-based detector. The monochromatic gamma-ray flux is calculated by assuming supersymmetric neutralino as a typical dark matter candidate. We discuss both the detection focusing on the Galactic center and in a scan mode which detects gamma-rays from the whole Galactic halo are compared. The detector performance for the purpose of monochromatic gamma-rays detection, with different energy and angular resolution, field of view, background rejection efficiencies, is carefully studied with both analytical and fast Monte-Carlo method.

  4. Cathodoluminescence and epitaxy after laser annealing of Cs{sup +}-irradiated {alpha}-quartz

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, P.K. [II. Physikalisches Institut, Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Gasiorek, S. [II. Physikalisches Institut, Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Dhar, S. [II. Physikalisches Institut, Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Lieb, K.P. [II. Physikalisches Institut, Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Schaaf, P. [II. Physikalisches Institut, Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany)]. E-mail: pschaaf@uni-goettingen.de

    2006-04-30

    In the course of a systematic investigation of dynamic, chemical, and laser-induced solid phase epitaxy of {alpha}-quartz after ion implantation, we have studied epitaxy and cathodoluminescence emission after 250 keV Cs-ion implantation and subsequent pulsed excimer laser treatment in air. Rutherford backscattering channelling analysis showed partial epitaxy for all the laser-irradiated samples; however, no full epitaxy was achieved. The optical properties of these samples were analyzed using cathodoluminescence spectroscopy, giving evidence of five emission bands at 2.42, 2.79, 3.25, 3.65, and 4.30 eV photon energy. Their intensity relation to the laser power and retained Cs-ion fraction are discussed and the present results will be compared with those obtained after chemical and dynamic epitaxy of quartz after alkali-ion, Ge, and Ba implantation.

  5. Electroluminescence and cathodoluminescence from polyethylene and polypropylene films: Spectra reconstruction from elementary components and underlying mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, B. [Université de Toulouse, UPS, INP, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, F-31062 Toulouse (France); Teyssedre, G.; Laurent, C. [Université de Toulouse, UPS, INP, LAPLACE (Laboratoire Plasma et Conversion d' Energie), 118 route de Narbonne, F-31062 Toulouse (France); CNRS, LAPLACE, F-31062 Toulouse (France)

    2016-01-14

    The mechanisms of electroluminescence from large band gap polymers used as insulation in electric components are still under debate. It becomes important to unravel the underlying physics of the emission because of increasing thermo-electric stress and a possible relationship between electroluminescence and field withstand. We report herein on the cathodoluminescence spectra of polyethylene and polypropylene films as a way to uncover the nature of its contributions to electroluminescence emission. It is shown that spectra from the two materials are structured around four elementary components, each of them being associated with a specific process contributing to the overall emission with different weights depending on excitation conditions and on materials. The cathodoluminescence and electroluminescence spectra of each material are reconstructed from the four spectral components and their relative contribution are discussed. It is shown that electroluminescence from polyethylene and polypropylene has the same origin pointing towards generic mechanisms in both.

  6. Electroluminescence and cathodoluminescence from polyethylene and polypropylene films: Spectra reconstruction from elementary components and underlying mechanisms

    Science.gov (United States)

    Qiao, B.; Teyssedre, G.; Laurent, C.

    2016-01-01

    The mechanisms of electroluminescence from large band gap polymers used as insulation in electric components are still under debate. It becomes important to unravel the underlying physics of the emission because of increasing thermo-electric stress and a possible relationship between electroluminescence and field withstand. We report herein on the cathodoluminescence spectra of polyethylene and polypropylene films as a way to uncover the nature of its contributions to electroluminescence emission. It is shown that spectra from the two materials are structured around four elementary components, each of them being associated with a specific process contributing to the overall emission with different weights depending on excitation conditions and on materials. The cathodoluminescence and electroluminescence spectra of each material are reconstructed from the four spectral components and their relative contribution are discussed. It is shown that electroluminescence from polyethylene and polypropylene has the same origin pointing towards generic mechanisms in both.

  7. A nano-graphite cold cathode for an energy-efficient cathodoluminescent light source

    Directory of Open Access Journals (Sweden)

    Alexander N. Obraztsov

    2013-08-01

    Full Text Available The development of new types of light sources is necessary in order to meet the growing demands of consumers and to ensure an efficient use of energy. The cathodoluminescence process is still under-exploited for light generation because of the lack of cathodes suitable for the energy-efficient production of electron beams and appropriate phosphor materials. In this paper we propose a nano-graphite film material as a highly efficient cold cathode, which is able to produce high intensity electron beams without energy consumption. The nano-graphite film material was produced by using chemical vapor deposition techniques. Prototypes of cathodoluminescent lamp devices with a construction optimized for the usage of nano-graphite cold cathodes were developed, manufactured and tested. The results indicate prospective advantages of this type of lamp and the possibility to provide advanced power efficiency as well as enhanced spectral and other characteristics.

  8. Cathodoluminescence, reflectivity changes, and accumulation of graphitic carbon during electron beam aging of phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Seager, C.H.; Tallant, D.R.; Warren, W.L. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

    1997-11-01

    We demonstrate that extended e-beam exposure produces a contaminating overlayer on phosphors whose opacity increases roughly linearly with time. Raman scattering data and optical analysis indicate that this layer is graphitic in nature, arising from the electron-beam-stimulated conversion of hydrocarbons adsorbed from the vacuum ambient. The presence of this contamination optically attenuates emitted cathodoluminescence, prevents many low energy electrons from ever reaching the phosphor grains, and exacerbates surface charging which reduces the arrival energy of electrons above 1.5{endash}2 keV. All of these effects are shown to impact cathodoluminescent output in an important way, but an accurate accounting of their total impact will be required to assess the importance of other degradation mechanisms like enhanced nonradiative electron-hole recombination at surfaces, both carbon and noncarbon related. {copyright} {ital 1997 American Institute of Physics.}

  9. Cathodoluminescence and photoluminescence of swift ion irradiation modified zinc oxide-porous silicon nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Yogesh [CIICAp, UAEM, Av. Univ. 1001, Col. Chamilpa, Cuer., Mor., C.P. 62209 (Mexico); CIMAV, Av. Miguel de Cervantes 120, Compl. Indus. Chih., Chih., C.P. 31109 (Mexico); Herrera, Manuel [CNyN-UNAM, Ensenada Apdo. Postal 14, CP. 22800, Ensenada, B.C. (Mexico); Singh, Fouran [Inter University Accelarator Centre, Aruna Asaf Ali Marg, New Delhi-110067 (India); Olive-Mendez, S.F. [CIMAV, Av. Miguel de Cervantes 120, Compl. Indus. Chih., Chih., C.P. 31109 (Mexico); Kanjilal, D.; Kumar, Shiv [Inter University Accelarator Centre, Aruna Asaf Ali Marg, New Delhi-110067 (India); Agarwal, V., E-mail: vagarwal@uaem.mx [CIICAp, UAEM, Av. Univ. 1001, Col. Chamilpa, Cuer., Mor., C.P. 62209 (Mexico)

    2012-09-20

    We report the room temperature cathodoluminescence and photoluminescence of swift ion irradiated (130 MeV Nickel ion) porous silicon zinc oxide nanocomposites. The evolution of a broad and flat emission band from 1.5 to 3.5 eV is demonstrated. Annealing effect of irradiation is found to result in a relative increase in the band edge emission. Emission wavelength can be tuned in the complete visible range by changing the substrate characteristics.

  10. Dislocation related droop in InGaN/GaN light emitting diodes investigated via cathodoluminescence

    OpenAIRE

    Pozina, Galia; Ciechonski, Rafal; Bi, Zhaoxia; SAMUELSON, Lars; Monemar, Bo

    2015-01-01

    Todays energy saving solutions for general illumination rely on efficient white light emitting diodes (LEDs). However, the output efficiency droop experienced in InGaN based LEDs with increasing current injection is a serious limitation factor for future development of bright white LEDs. We show using cathodoluminescence (CL) spatial mapping at different electron beam currents that threading dislocations are active as nonradiative recombination centers only at high injection conditions. At lo...

  11. Synthesis and cathodoluminescence characterization of ZrO{sub 2}:Er{sup 3+} films

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Hernández, A.; Guzmán-Mendoza, J. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada del Instituto Politécnico Nacional, Unidad Legaria, Av. Legaria 694, 11500 México, D. F. (Mexico); Rivera-Montalvo, T., E-mail: trivera@ipn.mx [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada del Instituto Politécnico Nacional, Unidad Legaria, Av. Legaria 694, 11500 México, D. F. (Mexico); Sánchez-Guzmán, D.; Guzmán-Olguín, J.C. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada del Instituto Politécnico Nacional, Unidad Legaria, Av. Legaria 694, 11500 México, D. F. (Mexico); García-Hipólito, M. [Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior, Cd. Universitaria, 04510 México, D. F. (Mexico); Falcony, C. [Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado Postal 14-740, 07000 México, D.F., México (Mexico)

    2014-09-15

    Trivalent erbium doped zirconium oxide films were deposited by the ultrasonic spray pyrolysis technique. Films were deposited using zirconium tetrachloride octahydrate (ZrCl{sub 4}O·8H{sub 2}O) and erbium nitrate hexahydrate ((NO{sub 3}){sub 3}Er·6H{sub 2}O) as precursors and deionized water as solvent. The dopant concentrations in the spray solution were 1, 3, 5, 10 and 15 at% in ratio to zirconium content. The films were deposited on corning glass substrates at different temperatures from 400 up to 550 °C. Films deposited at temperatures lower than 400 °C were amorphous, however, as substrate temperatures are increased, the ZrO{sub 2} films presented a better crystallinity and showed a tetragonal phase. Cathodoluminescence (CL) emission spectra showed bands centred at 524, 544 and 655 nm associated with the electronic transition of Er{sup 3+}. - Highlights: • The films of ZrO{sub 2}:Er{sup 3+} were obtained by spray pyrolysis. • Emission spectra of ZrO{sub 2}:Er{sup 3+} films were reported. • Cathodoluminescence of ZrO{sub 2}:Er{sup 3+} films was analyzed. • Cathodoluminescence of ZrO{sub 2}:Er{sup 3+} films showed strong dependence on substrate temperature and electron voltage.

  12. Dual energy computed tomography quantification of carotid plaques calcification: comparison between monochromatic and polychromatic energies with pathology correlation

    Energy Technology Data Exchange (ETDEWEB)

    Mannelli, Lorenzo [University of Washington, Departments of Radiology, Seattle, WA (United States); Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY (United States); MacDonald, Lawrence; Ferguson, Marina; Shuman, William P.; Xu, Dongxiang; Yuan, Chun; Mitsumori, Lee M. [University of Washington, Departments of Radiology, Seattle, WA (United States); Mancini, Marcello; Ragucci, Monica; Monti, Serena [IRCCS Fondazione SDN, Naples (Italy)

    2015-05-01

    We compared carotid plaque calcification detection sensitivity and apparent cross-sectional area on CT as a function of CT beam energy using conventional CT techniques and virtual mono-energetic CT images generated from dual-energy acquisitions. Five ex-vivo carotid endarterectomy (CEA) specimens were imaged with dual-energy computed tomography. Virtual monochromatic spectrum (VMS) CT images were reconstructed at energies between 40-140 keV. The same specimens were imaged using conventional polyenergetic spectrum (PS) CT with peak beam energies 80, 100, 120, and 140 kVp. The histological calcium areas on each corresponding CEA specimen were traced manually on digitized images of Toluidine-Blue/Basic-Fuchsin stained plastic sections. 40 keV VMS CT images provided high detection sensitivity (97 %) similar to conventional PS CT images (∝96 %). The calcification size measured on CT decreased systematically with increasing CT beam energy; the rate of change was larger for the VMS images than for PS images. From a single dual-energy CT, multiple VMS-CT images can be generated, yielding equivalent detection sensitivity and size correlations as conventional PS-CT in CEA calcification imaging. VMS-CT at 80-100 keV provided the most accurate estimates of calcification size, as compared to histology, but detection sensitivity was reduced for smaller calcifications on these images. (orig.)

  13. A study of cathodoluminescence and trace element compositional zoning in natural quartz from volcanic rocks: mapping titanium content in quartz.

    Science.gov (United States)

    Leeman, William P; MacRae, Colin M; Wilson, Nick C; Torpy, Aaron; Lee, Cin-Ty A; Student, James J; Thomas, Jay B; Vicenzi, Edward P

    2012-12-01

    This article concerns application of cathodoluminescence (CL) spectroscopy to volcanic quartz and its utility in assessing variation in trace quantities of Ti within individual crystals. CL spectroscopy provides useful details of intragrain compositional variability and structure but generally limited quantitative information on element abundances. Microbeam analysis can provide such information but is time-consuming and costly, particularly if large numbers of analyses are required. To maximize advantages of both approaches, natural and synthetic quartz crystals were studied using high-resolution hyperspectral CL imaging (1.2-5.0 eV range) combined with analysis via laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). Spectral intensities can be deconvolved into three principal contributions (1.93, 2.19, and 2.72 eV), for which intensity of the latter peak was found to correlate directly with Ti concentration. Quantitative maps of Ti variation can be produced by calibration of the CL spectral data against relatively few analytical points. Such maps provide useful information concerning intragrain zoning or heterogeneity of Ti contents with the sensitivity of LA-ICPMS analysis and spatial resolution of electron microprobe analysis.

  14. Trace elements and cathodoluminescence of detrital quartz in Arctic marine sediments – a new ice-rafted debris provenance proxy

    Directory of Open Access Journals (Sweden)

    A. Müller

    2013-07-01

    Full Text Available The records of ice-rafted debris (IRD provenance in the North Atlantic – Barents Sea allow the reconstruction of the spatial and temporal changes of ice-flow drainage patterns during glacial and deglacial periods. In this study a new approach to characterisation of the provenance of detrital quartz grains in the fraction > 500 μm of marine sediments offshore of Spitsbergen is introduced, utilizing scanning electron microscope backscattered electron and cathodoluminescence (CL imaging, combined with laser ablation inductively-coupled plasma mass spectrometry. Based on their micro-inclusions, CL and trace element characteristics the investigated IRD grains can be classified into five distinct populations. Three of the populations are indicative of potential IRD provenance provinces in the Storfjord area including Barentsøya and Egdeøya. The results imply that under modern (interglacial conditions IRD deposition along the western Spitsbergen margin is mainly governed by the East Svalbard Current controlling the ice-drift pattern. The presence of detrital quartz from local provinces, however, indicates that variations in IRD supply from western Spitsbergen may be quantified as well. In this pilot study it is demonstrated that this new approach applied on Arctic continental margin sediments, bears a considerable potential for the definition of the sources of IRD and thus of spatial/temporal changes in ice-flow drainage patterns during glacial/interglacial cycles.

  15. Sex and vision II: color appearance of monochromatic lights

    Directory of Open Access Journals (Sweden)

    Abramov Israel

    2012-09-01

    Full Text Available Abstract Background Because cerebral cortex has a very large number of testosterone receptors, we examined the possible sex differences in color appearance of monochromatic lights across the visible spectrum. There is a history of men and women perceiving color differently. However, all of these studies deal with higher cognitive functions which may be culture-biased. We study basic visual functions, such as color appearance, without reference to any objects. We present here a detailed analysis of sex differences in primary chromatic sensations. Methods We tested large groups of young adults with normal vision, including spatial and temporal resolution, and stereopsis. Based on standard color-screening and anomaloscope data, we excluded all color-deficient observers. Stimuli were equi-luminant monochromatic lights across the spectrum. They were foveally-viewed flashes presented against a dark background. The elicited sensations were measured using magnitude estimation of hue and saturation. When the only permitted hue terms are red (R yellow (Y, green (G, blue (B, alone or in combination, such hue descriptions are language-independent and the hue and saturation values can be used to derive a wide range of color-discrimination functions. Results There were relatively small but clear and significant, differences between males and females in the hue sensations elicited by almost the entire spectrum. Generally, males required a slightly longer wavelength to experience the same hue as did females. The spectral loci of the unique hues are not correlated with anomaloscope matches; these matches are directly determined by the spectral sensitivities of L- and M-cones (genes for these cones are on the X-chromosomes. Nor are there correlations between loci of pairs of unique hues (R, Y, G, B. Wavelength-discrimination functions derived from the scaling data show that males have a broader range of poorer discrimination in the middle of the spectrum. The

  16. The quasi-monochromatic ULF wave foreshock boundary at Venus

    Science.gov (United States)

    Shan, Lican; Mazelle, Christian; Meziane, Karim; Romanelli, Norberto; Ge, Yasong; Du, Aimin; Lu, Quanming; Zhang, Tielong

    2017-04-01

    The location of ULF quasi-monochromatic wave onsets upstream of Venus bow shock is explored using VEX magnetic field data. We report the existence of a spatial foreshock boundary from which ULF waves are present. It is found that the ULF boundary is sensitive to the interplanetary magnetic field (IMF) direction and appears well defined for a cone-angle larger than 30 degrees. In the Venusian foreshock, the slope of the boundary increases with the cone-angle and for a nominal direction of the IMF, it makes an inclination of 70 degrees with the Sun-Venus direction. Moreover, we have found that the velocity of an ion traveling along the ULF boundary presents a qualitative agreement with the hypothesis of a quasi-adiabatic reflection of a portion of the solar wind at the bow shock. For a nominal IMF direction, the ions associated with the boundary have enough momentum to overcome the solar wind convection. These elements strongly suggest that backstreaming ions upstream of Venus bow shock provide the main energy source of the ULF foreshock waves.

  17. The effect of monochromatic infrared energy on diabetic wound healing.

    Science.gov (United States)

    He, Yayi; Yip, Selina Ly; Cheung, Kwok-Kuen; Huang, Lin; Wang, Shijie; Cheing, Gladys Ly

    2013-12-01

    This study examined the effect of monochromatic infrared energy (MIRE) on diabetic wound healing. Fifteen diabetic rats were given MIRE intervention on their skin wounds located on the dorsum and compared with 15 control diabetic rats. Assessments were conducted for each group at weeks 1, 2 and 4 post wounding (five rats at each time point) by calculating the percentage of wound closures (WCs) and performing histological and immunohistochemical staining on sections of wound tissue. Evaluations of WCs and histological examinations of reepithelialisation, cellular content and granulation tissue formation showed no significant difference between the MIRE and the control group at each time point. Through semi-quantitative immunohistochemical staining, the deposition of type I collagen in the MIRE group was found to have improved when compared with the control group at the end of week 2 (P = 0.05). No significant differences in the myofibroblast population were detected between the two groups. In conclusion, MIRE appeared to promote collagen deposition in the early stage of wound healing in diabetic rats, but the overall wound healing in the MIRE group was not significantly different from that of the control group. © 2012 The Authors. International Wound Journal © 2012 John Wiley & Sons Ltd and Medicalhelplines.com Inc.

  18. How accurate are infrared luminosities from monochromatic photometric extrapolation?

    CERN Document Server

    Lin, Zesen; Kong, Xu

    2016-01-01

    Template-based extrapolations from only one photometric band can be a cost-effective method to estimate the total infrared (IR) luminosities ($L_{\\mathrm{IR}}$) of galaxies. By utilizing multi-wavelength data that covers across 0.35--500\\,$\\mathrm{\\mu m}$ in GOODS-North and GOODS-South fields, we investigate the accuracy of this monochromatic extrapolated $L_{\\mathrm{IR}}$ based on three IR spectral energy distribution (SED) templates (\\citealt[CE01]{Chary2001}; \\citealt[DH02]{Dale2002}; \\citealt[W08]{Wuyts2008a}) out to $z\\sim 3.5$. We find that the CE01 template provides the best estimate of $L_{\\mathrm{IR}}$ in {\\it Herschel}/PACS bands, while the DH02 template performs best in {\\it Herschel}/SPIRE bands. To estimate $L_{\\mathrm{IR}}$, we suggest that extrapolations from the available longest wavelength PACS band based on the CE01 template can be a good estimator. Moreover, if PACS measurement is unavailable, extrapolations from SPIRE observations but based on the \\cite{Dale2002} template can also provide ...

  19. Cell response to quasi-monochromatic light with different coherence

    Science.gov (United States)

    Budagovsky, A. V.; Solovykh, N. V.; Budagovskaya, O. N.; Budagovsky, I. A.

    2015-04-01

    The problem of the light coherence effect on the magnitude of the photoinduced cell response is discussed. The origins of ambiguous interpretation of the known experimental results are considered. Using the biological models, essentially differing in anatomy, morphology and biological functions (acrospires of radish, blackberry microsprouts cultivated in vitro, plum pollen), the effect of statistical properties of quasi-monochromatic light (λmax = 633 nm) on the magnitude of the photoinduced cell response is shown. It is found that for relatively low spatial coherence, the cell functional activity changes insignificantly. The maximal enhancement of growing processes (stimulating effect) is observed when the coherence length Lcoh and the correlation radius rcor are greater than the cell size, i.e., the entire cell fits into the field coherence volume. In this case, the representative indicators (germination of seeds and pollen, the spears length) exceeds those of non-irradiated objects by 1.7 - 3.9 times. For more correct assessment of the effect of light statistical properties on photocontrol processes, it is proposed to replace the qualitative description (coherent - incoherent) with the quantitative one, using the determination of spatial and temporal correlation functions and comparing them with the characteristic dimensions of the biological structures, e.g., the cell size.

  20. First Sub-arcsecond Collimation of Monochromatic Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Wagh, Apoorva G; Abbas, Sohrab; Treimer, Wolfgang, E-mail: nintsspd@barc.gov.in

    2010-11-01

    We have achieved the tightest collimation to date of a monochromatic neutron beam by diffracting neutrons from a Bragg prism, viz. a single crystal prism operating in the vicinity of Bragg incidence. An optimised silicon {l_brace}111{r_brace} Bragg prism has collimated 5.26A neutrons down to 0.58 arcsecond. In conjunction with a similarly optimised Bragg prism analyser of opposite asymmetry, this ultra-parallel beam yielded a 0.62 arcsecond wide rocking curve. This beam has produced the first SUSANS spectrum in Q {approx} 10{sup -6} A{sup -1} range with a hydroxyapatite casein protein sample and demonstrated the instrument capability of characterising agglomerates upto 150 {mu}m in size. The super-collimation has also enabled recording of the first neutron diffraction pattern from a macroscopic grating of 200 {mu}m period. An analysis of this pattern yielded the beam transverse coherence length of 175 {mu}m (FWHM), the greatest achieved to date for A wavelength neutrons.

  1. Coloring random graphs online without creating monochromatic subgraphs

    CERN Document Server

    Mütze, Torsten; Spöhel, Reto

    2011-01-01

    Consider the following random process: The vertices of a binomial random graph $G_{n,p}$ are revealed one by one, and at each step only the edges induced by the already revealed vertices are visible. Our goal is to assign to each vertex one from a fixed number $r$ of available colors immediately and irrevocably without creating a monochromatic copy of some fixed graph $F$ in the process. Our first main result is that for any $F$ and $r$, the threshold function for this problem is given by $p_0(F,r,n)=n^{-1/m_1^*(F,r)}$, where $m_1^*(F,r)$ denotes the so-called \\emph{online vertex-Ramsey density} of $F$ and $r$. This parameter is defined via a purely deterministic two-player game, in which the random process is replaced by an adversary that is subject to certain restrictions inherited from the random setting. Our second main result states that for any $F$ and $r$, the online vertex-Ramsey density $m_1^*(F,r)$ is a computable rational number. Our lower bound proof is algorithmic, i.e., we obtain polynomial-time...

  2. Cell response to quasi-monochromatic light with different coherence

    Energy Technology Data Exchange (ETDEWEB)

    Budagovsky, A V; Solovykh, N V [I.V.Michurin All-Russian Recearch Institute of Fruit Crops Genetics and Breeding (Russian Federation); Budagovskaya, O N [I.V.Michurin All-Russia Research and Development Institute of Gardening, Michurinsk, Tambov region (Russian Federation); Budagovsky, I A [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2015-04-30

    The problem of the light coherence effect on the magnitude of the photoinduced cell response is discussed. The origins of ambiguous interpretation of the known experimental results are considered. Using the biological models, essentially differing in anatomy, morphology and biological functions (acrospires of radish, blackberry microsprouts cultivated in vitro, plum pollen), the effect of statistical properties of quasi-monochromatic light (λ{sub max} = 633 nm) on the magnitude of the photoinduced cell response is shown. It is found that for relatively low spatial coherence, the cell functional activity changes insignificantly. The maximal enhancement of growing processes (stimulating effect) is observed when the coherence length L{sub coh} and the correlation radius r{sub cor} are greater than the cell size, i.e., the entire cell fits into the field coherence volume. In this case, the representative indicators (germination of seeds and pollen, the spears length) exceeds those of non-irradiated objects by 1.7 – 3.9 times. For more correct assessment of the effect of light statistical properties on photocontrol processes, it is proposed to replace the qualitative description (coherent – incoherent) with the quantitative one, using the determination of spatial and temporal correlation functions and comparing them with the characteristic dimensions of the biological structures, e.g., the cell size. (biophotonics)

  3. Relations between integrated and monochromatic luminosities of flat-spectrum radio quasars

    Institute of Scientific and Technical Information of China (English)

    Zhi-Fu Chen; Zhao-Yu Chen; Yi-Ping Qin; Min-Feng Gu; Lian-Zhong Lü; Cheng-Yue Su; You-Bing Li; Ye Chen

    2011-01-01

    We employ a sample of 362 flat-spectrum radio quasars (FSRQs) to calculate their integrated luminosities by integrating the spectral energy distribution (SED) constructed with multi-band (radio, IR, optical, UV and X-ray) data.We compare these luminosities with those estimated from monochromatic luminosities by multiplying them by the conventional bolometric correction factors.Our analysis shows that the integrated luminosities calculated from the SED are much larger than the bolometric luminosities estimated from monochromatic luminosities.Their departing behavior tightly correlates with radio luminosities.The relations between integrated and monochromatic luminosities are explored, which are regarded as empirical relations that might be more suitable to be applied to estimate integrated luminosities of FSRQs from their monochromatic luminosities.

  4. A monochromatized chopped beam of cold neutrons for low background experiments

    Energy Technology Data Exchange (ETDEWEB)

    Bussiere, A. (Lab. de Physique des Particules, 74 - Annecy le Vieux (France)); Grivot, P. (Inst. des Sciences Nucleaires, 38 - Grenoble (France)); Kossakowski, R. (Lab. de Physique des Particules, 74 - Annecy le Vieux (France)); Liaud, P. (Lab. de Physique des Particules, 74 - Annecy le Vieux (France)); Saintignon, P. de (Inst. des Sciences Nucleaires, 38 - Grenoble (France)); Schreckenbach, K. (Inst. Laue-Langevin, 38 - Grenoble (France))

    1993-07-15

    The design and performance of a monochromatized, chopped beam of cold neutrons are described. The beam is particularly suited for experiments where a low level of gamma ray and diffused neutron background is required. (orig.)

  5. Emission of monochromatic microwave radiation from a nonequilibrium condensation of excited magnons

    OpenAIRE

    Vannucchi, FS; Vasconcellos, AR; Luzzi,R.

    2013-01-01

    The observation of monochromatic emission of radiation from a nonequilibrium Bose-Einstein-like condensate of magnons suggests the possibility of creating a monochromatic microwave generator pumped by incoherent broadband sources. The device would have a tunable emitted frequency as a function of the applied constant magnetic field. We present an analysis of the mechanisms of interaction between the condensate of magnons and the radiation field producing the super-radiant emission of photons....

  6. Cathodoluminescence (CL) features of the Anatolian agates, hydrothermally deposited in different volcanic hosts from Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Hatipoglu, Murat, E-mail: murat.hatipoglu@deu.edu.t [Dokuz Eylul University, IMYO, Izmir Multidisciplinary Vocational School, Gemmology and Jewellery Programme, TR-35380 Buca-Izmir (Turkey); Ajo, David [Institute of Inorganic Chemistry and Surfaces, CNR, Corso Stati Uniti 4, I-35127 Padova (Italy); SMATCH (Scientific Methodologies Applied to Cultural Heritage), Largo Ugo Bartolomei 5, I-00136 Rome (Italy); Sezai Kirikoglu, M. [Istanbul Technical University, Faculty of Mine, Department of Geological Engineering, TR-34469 Maslak-Istanbul (Turkey)

    2011-06-15

    Two different types of multi-colored gem-quality agate samples were investigated. They are both found in the same area in the Cubuk-Ankara region of Turkey although the first group is morphologically and geologically distinct from the second, being nodular-shaped agates occurring in cavity-spaces of a rhyolite host rock with an acidic character. They generally do not have any macroscopic inclusions, but the second group of rather block-shaped agates occurs in the fracture-spaces of an andesite host rock with a more neutral character, i.e. of lower free silica content, and they may display pseudomorphic bar-like macroscopic inclusions. Cathodoluminescence results at room temperature were obtained using measurements with alternating current (AC) (at energies of 14 and 24 keV) as well as direct current (DC) (at 14 keV energy), and they display remarkably different patterns between the two types of agates. It reveals a relation between the CL emissions and the presence of some transition metal elements. It is obvious that all trace elements do not play a direct role. Gaussian fitting of the cathodoluminescence AC experimental data at 14 keV energy obtained from the agates of rhyolite host indicates that there are three major spectral emissions, the dominant one being in the longer-visible wavelength region (red region) at about 690 nm. Additionally, two lesser emission lines occur in the middle-visible wavelength region (yellow region) at about 590 nm, and in the smaller-visible wavelength region (blue region) at about 430 nm. In spite of these, the same data from the agates of andesite host indicate that there is only one remarkable spectral emission which is in the in the middle-visible wavelength region (yellow region) at about 590 nm. On the other hand, Gaussian fitting of the cathodoluminescence AC experimental data at 24 keV energy obtained from the agates of rhyolite host indicates that these initial spectral emissions shift from the red and yellow regions to

  7. Monochromatic 4-term arithmetic progressions in 2-colorings of $\\mathbb Z_n$

    CERN Document Server

    Lu, Linyuan

    2011-01-01

    This paper is motivated by a recent result of Wolf \\cite{wolf} on the minimum number of monochromatic 4-term arithmetic progressions(4-APs, for short) in $\\Z_p$, where $p$ is a prime number. Wolf proved that there is a 2-coloring of $\\Z_p$ with 0.000386% fewer monochromatic 4-APs than random 2-colorings; the proof is probabilistic and non-constructive. In this paper, we present an explicit and simple construction of a 2-coloring with 9.3% fewer monochromatic 4-APs than random 2-colorings. This problem leads us to consider the minimum number of monochromatic 4-APs in $\\Z_n$ for general $n$. We obtain both lower bound and upper bound on the minimum number of monochromatic 4-APs in all 2-colorings of $\\Z_n$. Wolf proved that any 2-coloring of $\\Z_p$ has at least $(1/16+o(1))p^2$ monochromatic 4-APs. We improve this lower bound into $(7/96+o(1))p^2$. Our results on $\\Z_n$ naturally apply to the similar problem on $[n]$ (i.e., $\\{1,2,..., n\\}$). In 2008, Parillo, Robertson, and Saracino \\cite{prs} constructed a 2-...

  8. Correlative near-infrared light and cathodoluminescence microscopy using Y2O3:Ln, Yb (Ln = Tm, Er) nanophosphors for multiscale, multicolour bioimaging

    Science.gov (United States)

    Fukushima, S.; Furukawa, T.; Niioka, H.; Ichimiya, M.; Sannomiya, T.; Tanaka, N.; Onoshima, D.; Yukawa, H.; Baba, Y.; Ashida, M.; Miyake, J.; Araki, T.; Hashimoto, M.

    2016-05-01

    This paper presents a new correlative bioimaging technique using Y2O3:Tm, Yb and Y2O3:Er, Yb nanophosphors (NPs) as imaging probes that emit luminescence excited by both near-infrared (NIR) light and an electron beam. Under 980 nm NIR light irradiation, the Y2O3:Tm, Yb and Y2O3:Er, Yb NPs emitted NIR luminescence (NIRL) around 810 nm and 1530 nm, respectively, and cathodoluminescence at 455 nm and 660 nm under excitation of accelerated electrons, respectively. Multimodalities of the NPs were confirmed in correlative NIRL/CL imaging and their locations were visualized at the same observation area in both NIRL and CL images. Using CL microscopy, the NPs were visualized at the single-particle level and with multicolour. Multiscale NIRL/CL bioimaging was demonstrated through in vivo and in vitro NIRL deep-tissue observations, cellular NIRL imaging, and high-spatial resolution CL imaging of the NPs inside cells. The location of a cell sheet transplanted onto the back muscle fascia of a hairy rat was visualized through NIRL imaging of the Y2O3:Er, Yb NPs. Accurate positions of cells through the thickness (1.5 mm) of a tissue phantom were detected by NIRL from the Y2O3:Tm, Yb NPs. Further, locations of the two types of NPs inside cells were observed using CL microscopy.

  9. Cathodoluminescence Study of Orientation-Patterned GaAs Crystals for Nonlinear Optics

    Science.gov (United States)

    Martínez, O.; Avella, M.; Hortelano, V.; Jiménez, J.; Lynch, C.; Bliss, D.

    2010-06-01

    Orientation-patterned (OP) GaAs crystals are very promising for their use in nonlinear optical applications. In particular, mid-infrared and terahertz lasers can be generated by frequency conversion from shorter-wavelength sources. However, the quality of the crystals is crucial for high conversion efficiency, as the presence of defects with electrooptical signatures can contribute to optical losses. The study of these defects is a step toward the improvement of OP-GaAs crystals. We present here a spectroscopic cathodoluminescence study of the distribution of the main defects. Tentative relations between defects and the optical propagation losses are discussed.

  10. Transient demonstration of exciton behaviours in solid state cathodoluminescence under different driving voltage

    Institute of Scientific and Technical Information of China (English)

    Zhang Fu-Jun; Zhao Su-Ling; Xu Zheng; Huang Jin-Zhao; Xu Xu-Rong

    2007-01-01

    In the solid state cathodoluminescence (SSCL), organic materials were excited by hot electrons accelerated in silicon oxide (SiO2) layer under alternating current (AC). In this paper exciton behaviours were analysed by using transient spectra under different driving voltages. The threshold voltages of SSCL and exciton ionization were obtained from the transient spectra. The recombination radiation occurred when the driving voltage went beyond the threshold voltage of exciton ionization. Prom the transient spectrum of two kinds of luminescence (exciton emission and recombination radiation), it was demonstrated that recombination radiation should benefit from the exciton ionization.

  11. Cathodoluminescent and electrical properties of an individual ZnO nanowire with oxygen vacancies

    Institute of Scientific and Technical Information of China (English)

    He Xiao-Bo; Yang Tian-Zhong; Cai Jin-Ming; Zhang Chen-Dong; Guo Hai-Ming; Shi Dong-Xia; Shen Cheng-Min; Gao Hong-Jun

    2008-01-01

    A single ZnO nanowire with intrinsic oxygen vacancies is utilized to fabricate four-contact device with focus ion beam lithography technique.Cathodoluminescent spectra indicate strong near-UV and green emission at both room temperature and low temperatures.Experimented measurement shows the temperature-dependent conductivity of the ZnO nanowire at low temperatures(below 100 K).The further theoretical analysis confirms that weak localization plays an important role in the electrical transport,which is attributed to the surface states induced by plenty of oxygen vacancies in ZnO nanowire.

  12. Cathodoluminescence studies of GaAs nano-wires grown on shallow-trench-patterned Si

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ling; Fan, Wen-Chung; Ku, Jui-Tai; Chang, Wen-Hao; Chen, Wei-Kuo; Chou, Wu-Ching [Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan (China); Ko, Chih-Hsin; Wu, Cheng-Hsien; Lin, You-Ru; Wann, Clement H [Taiwan Semiconductor Manufacturing Co., Ltd, Hsinchu 300, Taiwan (China); Hsu, Chao-Wei; Chen, Yung-Feng; Su, Yan-Kuin, E-mail: acceptor.ep89g@nctu.edu.tw, E-mail: wuchingchou@mail.nctu.edu.tw [Institute of Microelectronics and Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan (China)

    2010-11-19

    The optical properties of GaAs nano-wires grown on shallow-trench-patterned Si(001) substrates were investigated by cathodoluminescence. The results showed that when the trench width ranges from 80 to 100 nm, the emission efficiency of GaAs can be enhanced and is stronger than that of a homogeneously grown epilayer. The suppression of non-radiative centers is attributed to the trapping of both threading dislocations and planar defects at the trench sidewalls. This approach demonstrates the feasibility of growing nano-scaled GaAs-based optoelectronic devices on Si substrates.

  13. LabVIEW-based control and data acquisition system for cathodoluminescence experiments.

    Science.gov (United States)

    Bok, J; Schauer, P

    2011-11-01

    Computer automation of cathodoluminescence (CL) experiments using equipment developed in our laboratory is described. The equipment provides various experiments for CL efficiency, CL spectra, and CL time response studies. The automation was realized utilizing the graphical programming environment LabVIEW. The developed application software with procedures for equipment control and data acquisition during various CL experiments is presented. As the measured CL data are distorted by technical limitations of the equipment, such as equipment spectral sensitivity and time response, data correction algorithms were incorporated into the procedures. Some examples of measured data corrections are presented.

  14. Combinatorial Ion Synthesis and Cathodoluminescence Analyses of Materials Libraries on Thermally Grown SiO2

    Institute of Scientific and Technical Information of China (English)

    Chang-Ming Chen; H.C.Pan; D.Z. Zhu; J.Hu; M.Q.Li

    2000-01-01

    We first report a method combining ion implantationand physical masking to generate material libraries of various ion-implanted samples. This approach offers rapid synthesis of samples with potential new compounds formed in the matrix, which may have specific luminescent properties. The depthresolved cathodoluminescence (CL) measurements, accompanied with Rutherford backscattering spectrometry (RBS) and proton elastic scattering (PES) revealed some specific optical properties in the samples correlated with implanted ion distributions. These measurements are capable of nondestructively and rapidly characterizing the composition and the inhomogeneity of the combinatorial film libraries, which may determine their physical properties.

  15. Cathodoluminescence zoning and minor elements in forsterites from the Murchison (C2) and Allende (C3V) carbonaceous chondrites

    Energy Technology Data Exchange (ETDEWEB)

    Steele, I.M.; Smith, J.V.; Skirius, C. (Chicago Univ., IL (USA). Dept. of Geophysical Sciences)

    1985-01-24

    The authors have applied the cathodoluminescence technique to look for textural features of olivine in carbonaceous meteorites relevant to the unresolved dispute over its origin, whether from a vapour or a liquid. The cathodoluminescence photographs of forsterite grains in Murchison (C2) and Allende (C3) meteorites reveal a blue core (inclusion-free) with planar boundaries to a red or dark rim. Also performed are high-precision electron microprobe analyses revealing in these forsterites unusually large amounts of the 'minor' elements Al, Ti and Ca in the blue cores, suggesting formation by crystallization at high temperatures from a source rich in these metals.

  16. Cathodoluminescence and Raman Spectromicroscopy of Forsterite in Tagish Lake Meteorite: Implications for Astromineralogy

    Directory of Open Access Journals (Sweden)

    Arnold Gucsik

    2016-01-01

    Full Text Available The Tagish Lake meteorite is CI/CM2 chondrite, which fell by a fireball event in January 2000. This study emphasizes the cathodoluminescence (CL and Raman spectroscopical properties of the Tagish Lake meteorite in order to classify the meteoritic forsterite and its relation to the crystallization processes in a parent body. The CL-zoning of Tagish Lake meteorite records the thermal history of chondrules and terrestrial weathering. Only the unweathered olivine is forsterite, which is CL-active. The variation of luminescence in chondrules of Tagish Lake meteorite implies chemical inhomogeneity due to low-grade thermal metamorphism. The blue emission center in forsterite due to crystal lattice defect is proposed as being caused by rapid cooling during the primary crystallization and relatively low-temperature thermal metamorphism on the parent body of Tagish Lake meteorite. This is in a good agreement with the micro-Raman spectroscopical data. A combination of cathodoluminescence and micro-Raman spectroscopies shows some potentials in study of the asteroidal processes of parent bodies in solar system.

  17. Cathodoluminescence study of SnO{sub 2} powders aimed for gas sensor applications

    Energy Technology Data Exchange (ETDEWEB)

    Korotcenkov, G. [Technical University of Moldova, Chisinau (Moldova, Republic of)]. E-mail: ghkoro@yahoo.com; Nazarov, M. [Technical University of Moldova, Chisinau (Moldova, Republic of); Zamoryanskaya, M.V. [A.F. Ioffe Physical Technical Institute, RAS, St. Petersburg, Russia (Russian Federation); Ivanov, M. [Technical University of Moldova, Chisinau (Moldova, Republic of); Cirera, A. [EME/CERMAE. Dep. Elect., University of Barcelona, Barcelona (Spain); Shimanoe, K. [Kyushu University, Kasuga-shi, Fukuoka (Japan)

    2006-06-15

    In this paper we report on cathodoluminescence (CL) spectra of SnO{sub 2} powders, synthesized using the wet chemical route. The analysis of influence of the modes of calcination (T {sub an}-450-800 deg. C), and doping by both Pd and Pt (0.01-10.0 wt.%) on CL spectra was made. It was found that the measurement of CL spectra could be an effective research method of nanostructured metal oxides, aimed for gas sensor applications. It was established that in nanocrystalline SnO{sub 2} the same system of energy levels, associated with radiative recombination, as in single crystalline and polycrystalline SnO{sub 2}, is retained. It was found that doping by both Pd and Pt modifies the structural properties of SnO{sub 2} grains. Also, there is an optimum doping; near 0.1-0.2 wt.%, at which a maximum intensity of cathodoluminescence is reached. It was concluded that for low concentrations of both Pd and Pt additives in SnO{sub 2} an improvement of the material's crystal structure is promoted, and is associated with a decrease in the non-radiating recombination rate.

  18. Cathodoluminescence microscopy of hydrothermal and flux grown ZnO single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Urbieta, A.; Fernandez, P.; Piqueras, J.; Hardalov, Ch. [Departamento de Fisica de Materiales, Facultad de Fisicas, Universidad Complutense, Madrid (Spain); Sekiguchi, T. [Nanomaterials Laboratory, National Institute for Materials Science, Sengen, Tsukuba (Japan)

    2001-10-07

    Bulk ZnO single crystals grown by the hydrothermal and flux methods have been characterized by steady-state and time resolved cathodoluminescence measurements performed on the different crystalline faces. A shift of the peak near band edge towards lower energies is observed in spectra recorded with increasing delay times. This behaviour is often observed in the etch pit regions in alkali flux grown crystals, which suggests the presence of a band related to dislocations or to the point defects surrounding the dislocations. In the low-energy region, cathodoluminescence spectra show that the relative intensity of the different components of the deep level band also depends on the atomic structure of the face under study. This complex behaviour is clearly revealed from the time resolved spectra. The differences observed are attributed to the nature of the defects present in each face and, in particular, to different impurity incorporation processes that could be mainly controlled by the atomic configuration and polarity of the planes. (author)

  19. Cycles and transitivity by monochromatic paths in arc-coloured digraphs

    Directory of Open Access Journals (Sweden)

    Enrique Casas-Bautista

    2015-11-01

    The result by Sands et al. (1982 that asserts: Every 2-coloured digraph has a kernel by monochromatic paths, and the result by Galeana-Sánchez et al. (2011 that asserts: If D is a finite m-coloured digraph that admits a partition {C1,C2} of the set of colours of D such that for each i∈{1,2} every cycle in the subdigraph D[Ci] spanned by the arcs with colours in Ci is monochromatic, C(D does not contain neither rainbow triangles nor rainbow P3⃗ (path of length 3 involving colours of both C1 and C2; then D has a kernel by monochromatic paths.

  20. Note on 2-edge-colorings of complete graphs with small monochromatic k-connected subgraphs

    Institute of Scientific and Technical Information of China (English)

    JIN Ze-min; WANG Yu-ling; WEN Shi-li

    2014-01-01

    Bollob´as and Gy´arf´as conjectured that for n > 4(k-1) every 2-edge-coloring of Kn contains a monochromatic k-connected subgraph with at least n-2k+2 vertices. Liu, et al. proved that the conjecture holds when n ≥ 13k-15. In this note, we characterize all the 2-edge-colorings of Kn where each monochromatic k-connected subgraph has at most n-2k+2 vertices for n≥13k-15.

  1. Dispersion-free monochromatization method for selecting a single-order harmonic beam

    CERN Document Server

    Takahashi, Eiji J; Ichimaru, Satoshi; Midorikawa, Katsumi

    2015-01-01

    We propose a method to monochromatize multiple orders of high harmonics by using a proper designed multilayer mirror. Multilayer mirrors designed by our concept realize the perfect extraction of a single-order harmonic from multiple-order harmonic beam, and exhibit broadband tenability and high reflectivity in the soft-x-ray region. Furthermore, the proposed monochromatization method can preserve the femtosecond to attosecond pulse duration for the reflected beam. This device is very useful for ultrafast soft x-ray experiments that require high-order harmonic beams, such as femtosecond/attosecond, time-resolved, pump-probe spectroscopy.

  2. Cathodoluminescence study of e-irradiated and plastically deformed ZnO crystals

    Energy Technology Data Exchange (ETDEWEB)

    Avella, M.; Hortelano, V.; Martinez, O.; Jimenez, J. [GdS Optronlab., Univ. de Valladolid, Paseo de Belen 1, 47011 Valladolid (Spain); Mass, J. [Grupo de Fisica Aplicada, Universidad del Norte, km 5, Via Pto. Colombia, Barranquilla (Colombia); Wang, B. [Solid State Scientific Corp., 27-2 Wright Rd., Hollis, NH 03049 (United States); Drevinsky, P.; Bliss, D. [Air Force Research Laboratory, Sensors Directorate, Hanscom AFB, MA 01731 (United States)

    2012-07-15

    Intrinsic defects are generated by e-irrradiation, and plastic deformation in ZnO crystals. Spectrally resolved cathodoluminescence (CL) experiments permit the analysis of the optical signature of those defects. We present herein a CL analysis of ZnO crystals irradiated with high energy electrons, and plastically deformed by Vickers indentation. Spectral changes around 3.3 eV and in the deep level emission are observed in the irradiated samples. These changes are compared to those observed around the extended defects introduced by Vickers indentation, which present a similar signature to the e-irradiated samples, suggesting relation between the defects generated by plastic deformation and e-irradiation. Zn vacancies seem to be the dominant defects generated in both processes (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. Cathodoluminescence characterization of polystyrene-BaZrO3 hybrid composites

    Science.gov (United States)

    Savchyn, V. P.; Popov, A. I.; Aksimentyeva, O. I.; Klym, H.; Horbenko, Yu. Yu.; Serga, V.; Moskina, A.; Karbovnyk, I.

    2016-07-01

    The radiation properties and the electronic structure of hybrid composites based on suspension polystyrene (PS) and nanocrystals of BaZrO3 (BZO) (d < 50 nm) have been studied using luminescent spectroscopy and x-ray analysis. A strong cathodoluminescence (CL) in BZO-nanocrystals is observed in temperature range 80-293 K. It is modified in BZO-PS composites: both the low- and a high-energy bands (near 4 eV) appear, together with a significant reduction in the CL intensity. A decrease of the lattice parameter a for BZO phase in the composite and the modification of CL spectra indicate for changes in the nanocrystalline structure induced by the polymer.

  4. Excitons and defects in homoepitaxial diamond films from cathodoluminescence of p-/p+ samples

    Science.gov (United States)

    Wade, M.; Kadri, M.; Bustarret, E.; Deneuville, A.; Muret, P.; Araujo, D.

    2004-09-01

    We study the signals from excitons and defects from the cathodoluminescence spectra (CL) of the p-/pseudo substrate sample. The CL from the p- film are determined from the variation of the CL of the sample as the voltage of the exciting electron beam increases. At the lower voltages, it probes the p- film. The CL is dominated by the free exciton associated with the TO phonon (FETO, FWHM = 6 meV), but shows also small signals (ratio = 5 × 10-2) mainly from the A band (and other 2.6, 3.6 and 4.05 eV wide bands) and tiny signals from the 5 RL defect. At the higher voltages it probes also the Ib substrate and is dominated by the signals of the H3 defects in the Ib substrate. The p- film appears almost homogeneous, and of good quality from the characteristics of its exciton.

  5. Variations in Cathodoluminescent Intensity of Spacecraft Materials Exposed to Energetic Electron Bombardment

    Science.gov (United States)

    Dekany, Justin; Christensen, Justin; Dennison, J. R.; Jensen, Amberly Evans; Wilson, Gregory; Schneider, Todd; Bowers, Charles W.; Meloy, Robert

    2015-01-01

    Many contemporary spacecraft materials exhibit cathodoluminescence when exposed to electron flux from the space plasma environment. A quantitative, physics-based model has been developed to predict the intensity of the total glow as a function of incident electron current density and energy, temperature, and intrinsic material properties. We present a comparative study of the absolute spectral radiance for more than 20 types of dielectric and composite materials based on this model which spans more than three orders of magnitude. Variations in intensity are contrasted for different electron environments, different sizes of samples and sample sets, different testing and analysis methods, and data acquired at different test facilities. Together, these results allow us to estimate the accuracy and precision to which laboratory studies may be able to determine the response of spacecraft materials in the actual space environment. It also provides guidance as to the distribution of emissions that may be expected for sets of similar flight hardware under similar environmental conditions.

  6. Flexible, cathodoluminescent and free standing mesoporous silica films with entrapped quasi-2D perovskites

    Science.gov (United States)

    Vassilakopoulou, Anastasia; Papadatos, Dionysios; Koutselas, Ioannis

    2017-04-01

    The effective entrapment of hybrid organic-inorganic semiconductors (HOIS) into mesoporous polymer-silica hybrid matrices, formed as free standing flexible films, is presented for the first time. A blend of quasi-2D HOIS, simply synthesized by mixing two-dimensional (2D) and three dimensional (3D) HOIS, exhibiting strong photoluminescence, is embedded into porous silica matrices during the sol-gel synthesis, using tetraethylorthosilicate as precursor and Pluronic F-127 triblock copolymer as structure directing agent, under acidic conditions. The final nanostructure hybrid forms flexible, free standing films, presenting high cathodoluminescence and long stable excitonic luminescence, indicating the protective character of the hybrid matrix towards the entrapped perovskite. A significant result is that the photoluminescence of the entrapped HOIS is not affected even after films' prolonged exposure to water.

  7. Solvothermal route to S-deficient CoS nanoplates and their cathodoluminescence and magnetic properties.

    Science.gov (United States)

    Lei, M; Fu, X L; Yang, H J; Wang, Y G; Zhang, Y B; Li, P G

    2012-03-01

    A facile solvothermal method was developed to fabricate CoS nanoplates using ethylenediamine as solvent. The microstructure characterizations indicate that the CoS nanoplates have well-crystalline hexagonal phase and regular hexagonal or pentagonal shape. The XPS and ICP-AES measurements confirm the chemical composition of nanoplates is S-deficient CoS0.921. Cathodoluminescence spectra of both a large area of the nanoplates and individual nanoplate show broad emission bands centered at 615 nm. Magnetic measurements including magnetization dependence of temperature and magnetic hysteresis loops reveals that the CoS nanoplates exhibit room-temperature ferromagnetic behavior. It is found that intrinsic point defects mainly as V(s), Co(i) and/or the complex defects of V(s) and Co(i) should be responsible for both the broad emission band and the unique ferromagnetism.

  8. Cathodoluminescence microscopy and spectroscopy of micro- and nanodiamonds: an implication for laboratory astrophysics.

    Science.gov (United States)

    Gucsik, Arnold; Nishido, Hirotsugu; Ninagawa, Kiyotaka; Ott, Ulrich; Tsuchiyama, Akira; Kayama, Masahiro; Simonia, Irakli; Boudou, Jean-Paul

    2012-12-01

    Color centers in selected micro- and nanodiamond samples were investigated by cathodoluminescence (CL) microscopy and spectroscopy at 298 K [room temperature (RT)] and 77 K [liquid-nitrogen temperature (LNT)] to assess the value of the technique for astrophysics. Nanodiamonds from meteorites were compared with synthetic diamonds made with different processes involving distinct synthesis mechanisms (chemical vapor deposition, static high pressure high temperature, detonation). A CL emission peak centered at around 540 nm at 77 K was observed in almost all of the selected diamond samples and is assigned to the dislocation defect with nitrogen atoms. Additional peaks were identified at 387 and 452 nm, which are related to the vacancy defect. In general, peak intensity at LNT at the samples was increased in comparison to RT. The results indicate a clear temperature-dependence of the spectroscopic properties of diamond. This suggests the method is a useful tool in laboratory astrophysics.

  9. Solid solution, phase separation, and cathodoluminescence of GaP-ZnS nanostructures.

    Science.gov (United States)

    Liu, Baodan; Bando, Yoshio; Dierre, Benjamin; Sekiguchi, Takashi; Golberg, Dmitri; Jiang, Xin

    2013-09-25

    Quaternary solid-solution nanowires made of GaP and ZnS have been synthesized through well-designed synthetic routines. The as-synthesized GaP-ZnS solid-solution nanowires exhibit decent crystallinity with the GaP phase as the host, while a large amount of twin structural defects are observed in ZnS-rich nanowires. Cathodoluminescence studies showed that GaP-rich solid-solution nanowires have a strong visible emission centered at 600 nm and the ZnS-rich solid-solution nanowires exhibited a weak emission peak in the UV range and a broad band in the range 400-600 nm. The formation mechanism, processes, and optical emissions of GaP-ZnS solid-solution nanowires were discussed in detail.

  10. Cathodoluminescence of Cr-doped diamond-like carbon film by filtered cathodic vacuum arc plasma

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Meng-Wen; Jao, Jui-Yun [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan (China); Lin, Chun-Chun; Hsieh, Wei-Jen; Yang, Yu-Hsiang [Department of Materials Science and Engineering, National Tsing Hua University, 101, Sec. 2, Kuang-Fu Road, Hsinchu 300, Taiwan (China); Cheng, Li-Shin; Shieu, F.S. [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan (China); Shih, Han C., E-mail: hcshih@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung 402, Taiwan (China); Department of Materials Science and Engineering, National Tsing Hua University, 101, Sec. 2, Kuang-Fu Road, Hsinchu 300, Taiwan (China); Institute of Materials Science and Nanotechnology, Chinese Culture University, 55 Hwa Kang Road, Yang Ming Shan, Taipei 111, Taiwan (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer The formation of the DLC:Cr films dependent on the flow rates of C{sub 2}H{sub 2}/Ar have been achieved in our FCVA plasma. Black-Right-Pointing-Pointer The amorphous DLC:Cr have high sp{sup 2} content can be completely converted to nanocrystalline Cr{sub 3}C{sub 2}. Black-Right-Pointing-Pointer The effect of doping with Cr is apparently to change the band structure of the DLC and its consequent cathodoluminescence property. - Abstract: Cr doped diamond-like carbon (DLC:Cr) film was synthesized in various flow rates of C{sub 2}H{sub 2}/Ar under a substrate voltage of -50 V at 500 Degree-Sign C by a filtered cathodic vacuum arc plasma. This work has found that the structure of the films was correlated to the flow rate of C{sub 2}H{sub 2}/Ar but the luminescence properties are similar. The cathodoluminescence spectra of DLC:Cr films obtained at 1.9-2.4 eV verifies that the luminescence from the films is in the visible region. The incorporation of Cr into the carbon network results in red emission shifted to 1.99 eV and the orange emission (2.03 eV) also appeared due to the transitions between chromium-related electron levels and {sigma}* states. The peak at 2.10 eV may result from the defects of the structures in DLC:Cr films.

  11. Cathodoluminescence and Raman characteristics of CaSO{sub 4}:Tm{sup 3+}, Cu phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Ekdal, E. [Ege University, Institute of Nuclear Sciences, 35100 Bornova, İzmir (Turkey); Guinea, J. Garcia [MuseoNacional Ciencias Naturales, Jose Gutierrez Abascal 2, Madrid 28006 (Spain); Kelemen, A. [Centre for Energy Research, Radiation Safety Laboratory, P.O. Box 49, H-1121 Budapest (Hungary); Ayvacikli, M. [Celal Bayar University, Faculty of Arts and Sciences, Department of Physics, Muradiye, Manisa (Turkey); Canimoglu, A. [Nigde University, Faculty of Arts and Sciences, Department of Physics, Nigde (Turkey); Jorge, A. [MuseoNacional Ciencias Naturales, Jose Gutierrez Abascal 2, Madrid 28006 (Spain); Karali, T. [Ege University, Institute of Nuclear Sciences, 35100 Bornova, İzmir (Turkey); Can, N., E-mail: cannurdogan@yahoomail.com [Celal Bayar University, Faculty of Arts and Sciences, Department of Physics, Muradiye, Manisa (Turkey); Physics Department, Jazan University, P.O. Box 114, 45142 Jazan (Saudi Arabia)

    2015-05-15

    The physical characterization and phosphor emission spectra are presented for CaSO{sub 4} doped with Tm and Cu. All spectral wavelengths are related to electronic transitions of Tm{sup 3+} ions. The powder X-ray diffraction pattern showed that the compound exhibits orthorhombic structure and all reflections were indexed without any other secondary impurity phases. Chemical and structural properties of the samples have been characterized by means of Raman spectroscopy and environmental scanning electron microscope (ESEM) with an attached X-ray energy dispersive system (EDS). Group frequencies concept is essential point to the interpretation of the bands due to the main SO{sub 4} vibrational units and these displayed main characteristic intensive Raman bands including typical strong intensity at 1016 cm{sup −1} that corresponds to ν{sub 1}SO{sub 4} vibrational mode. From the spatially-resolved cathodoluminescence (CL) spectrum, main emission bands of Tm{sup 3+} centered at 346, 362, and 452 nm, due to the respective transitions of {sup 3}P{sub 0}→{sup 3}H{sub 4}, {sup 1}D{sub 2}→{sup 3}H{sub 6}, {sup 1}D{sub 2}→{sup 3}F{sub 4} were clearly identified. The study is novel as no such CL-ESEM data are available for this doped compound. - Highlights: • Characteristic and cathodoluminescence properties of CaSO{sub 4}:Tm{sup 3+}, Cu have been investigated. • Several sharp and strong CL emission bands due to rare earth ion were observed for rare earth doped sample. • The nature and limitation of the interaction between CaSO{sub 4} and the activator ions were discussed.

  12. Effect of a combination of green and blue monochromatic light on broiler immune response.

    Science.gov (United States)

    Zhang, Ziqiang; Cao, Jing; Wang, Zixu; Dong, Yulan; Chen, Yaoxing

    2014-09-05

    Our previous study suggested that green light or blue light would enhance the broiler immune response; this study was conducted to evaluate whether a combination of green and blue monochromatic light would result in improved immune response. A total of 192 Arbor Acre male broilers were exposed to white light, red light, green light, and blue light from 0 to 26 days. From 27 to 49 days, half of the broilers in green light and blue light were switched to blue light (G-B) and green light (B-G), respectively. The levels of anti-Newcastle disease virus (NDV) and anti-bovine serum albumin (BSA) IgG in G-B group were elevated by 11.9-40.3% and 17.4-48.7%, respectively, compared to single monochromatic lights (Plight groups. However, the serum TNF-α concentration in the G-B group was reduced by 3.64-40.5% compared to other groups, and no significant difference was found between the G-B and B-G groups in any type of detection index at the end of the experiment. These results suggested that the combination of G-B and B-G monochromatic light could effectively enhance the antibody titer, the proliferation index of lymphocytes and alleviate the stress response in broilers. Therefore, the combination of green and blue monochromatic light can improve the immune function of broilers. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Pustular Palmoplantar Psoriasis Successfully Treated with Nb-UVB Monochromatic Excimer Light: A Case-Report

    Directory of Open Access Journals (Sweden)

    Serena Gianfaldoni

    2017-07-01

    Full Text Available Barber’s palmoplantar pustulosis (PPP is a form of localised pustular psoriasis, affecting the palmar and plantar surfaces. It is a chronic disease, with a deep impact on the patients’ quality of life. The Authors discuss a case of Baber Psoriasis successfully treated with monochromatic excimer light.

  14. Resonant three-photon ionization of hydrogenic atoms by a non-monochromatic laser field

    NARCIS (Netherlands)

    Yakhontov, V.; Santra, R.; Jungmann, K.

    1999-01-01

    We present ionization probability and lineshape calculations for the two-step three- photon ionization process, 1S (2(h)over-bar-omega)under-right-arrow, 2S ((h)over-bar-omega)under-right-arrow epsilon P, of the ground state of hydrogenic atoms in a non-monochromatic laser field with a time-dependen

  15. Resonant three-photon ionization of hydrogenic atoms by a non-monochromatic laser field

    NARCIS (Netherlands)

    Yakhontov, V.; Santra, R.; Jungmann, K.

    1999-01-01

    We present ionization probability and lineshape calculations for a specifed two-step three-photon ionization process of the ground state of hydrogenic atoms in a non-monochromatic laser field with a time-dependent amplitude. Within the framework of a three-level model, the AC Stark shifts and non-ze

  16. Broadband EM radiation amplification by means of a monochromatically driven two-level system

    Science.gov (United States)

    Soldatov, Andrey V.

    2017-02-01

    It is shown that a two-level quantum system possessing dipole moment operator with permanent non-equal diagonal matrix elements and driven by external semiclassical monochromatic high-frequency electromagnetic (EM) (laser) field can amplify EM radiation waves of much lower frequency.

  17. Infrared upconversion hyperspectral imaging

    DEFF Research Database (Denmark)

    Kehlet, Louis Martinus; Tidemand-Lichtenberg, Peter; Dam, Jeppe Seidelin

    2015-01-01

    conversion process. From this, a sequence of monochromatic images in the 3.2-3.4 mu m range is generated. The imaged object consists of a standard United States Air Force resolution target combined with a polystyrene film, resulting in the presence of both spatial and spectral information in the infrared...

  18. Cathodoluminescence zoning and minor elements in forsterites from the Murchison (C2) and Allende (C3V) carbonaceous chondrites

    Science.gov (United States)

    Steele, I. M.; Smith, J. V.; Skirius, C.

    1985-01-01

    Cathodoluminescence has been applied to look for textural features of olivine in carbonaceous meteorites relevant to the unresolved dispute over the origin of the olivine, whether from a vapor or a liquid. Cathodoluminescence photographs of forsterite grains in Murchison (C2) and Allende (C3) meteorites presented here reveal a blue core with planar boundaries to a red or dark rim. High-precision electron microprobe analyses have been performed which reveal unusually large amounts of the 'minor' elements Al, Ti, and Ca in the blue cores of these forsterites, suggesting formation by crystallization at high temperatures from a source rich in these metals. Following conclusions drawn from previous analyses of olivine in meteorites, it is argued that the minor element signature should be able to characterize olivines in micrometeorites and in deep-sea particles.

  19. Characterization of kesterite thin films fabricated by rapid thermal processing of stacked elemental layers using spatially resolved cathodoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Künecke, Ulrike; Hetzner, Christina; Möckel, Stefan [Materials Department 6, University of Erlangen-Nürnberg (FAU), Martensstr, 7, D-91058 Erlangen (Germany); Yoo, Hyesun; Hock, Rainer [Crystallography and Structure Physics, University of Erlangen-Nürnberg (FAU), Staudtstr, 3, 91058 Erlangen (Germany); Wellmann, Peter, E-mail: peter.wellmann@fau.de [Materials Department 6, University of Erlangen-Nürnberg (FAU), Martensstr, 7, D-91058 Erlangen (Germany)

    2015-05-01

    We report on the microstructure analysis of kesterite (Cu{sub 2}ZnSnSe{sub 4}) layers from rapid thermal processing of sequential elemental layers by spatially resolved cathodoluminescence in a scanning electron microscope. Energy dispersive X-ray fluorescence, X-ray diffraction and Raman spectroscopy were carried out for the validation of the findings. Special emphasis is put on the discussion of the occurrence of the secondary phases Cu{sub 2}SnSe{sub 3}, Cu{sub 2}Se, ZnSe and SnSe. - Highlights: • Spectrally resolved cathodoluminescence of Cu{sub 2}ZnSnSe{sub 4} • Material analysis with a μm spatial resolution • Determination of secondary phases Cu{sub 2}SnSe{sub 3}, Cu{sub 2}Se, SnSe and ZnSe.

  20. Cathodoluminescence characterization of quartz grains from the Upper Cretaceous of dinosaur fossil localities in the Gobi desert, Mongolia

    Science.gov (United States)

    Saneyoshi, M.; Nishido, H.; Masuda, R.; Tsogtbaatar, K.; Chinzorig, T.

    2013-12-01

    The Upper Cretaceous eolian sediments in Mongolia's Gobi desert are one of the most important occurrences of the dinosaurs in the world. Large numbers of confiscated dinosaur fossils illegally worked out by poachers has been stored in the Mongolian Paleontological Center at Ulaanbaatar. In most cases, their localities are unknown. The purpose of this study is to identify their localities by cathodoluminescence (CL) features of quartz grains attached to the dinosaur specimens by comparing to the quartz samples collected from the sediments of circumjacent resources in this area. This study focuses on the confiscated specimen which makes up the nest with the babies' Protoceratops. Most of all Protoceratops in every growth process, have been discovered from the Djadokhta Formation in the Gobi desert. This formation crops out at Tugrikin Shireh and Bayn Dzak in the central part of the Gobi desert, and is derived from medium- to fine-grained sand mainly composed of quartz grains, of which sedimentary environments should be obvious to be eolian. The formation age of the sand beds at Tugrikin Shireh and Bayn Dzak has been estimated to be Middle Campanian. CL spectra of quartz have been demonstrated to show different features between the quartz from hydrothermal, plutonic, volcanic and metamorphic origins, suggesting the spectra reflect the condition of the quartz formation and the local environment. Therefore, we have applied the CL characterization of quartz grains to the evaluation of the provenance of the desert sediments. The quartz grains after sieving (#60-80 mesh size) were embedded in the brass holders with non-luminescent epoxy resin, and their surfaces were polished with 1 μm diamond abrasive. Color CL images obtained by the Luminoscope exhibit blue, violet and red emissions in the grains, suggesting various types of emission centers in the quartz. SEM-CL analysis was conducted using an SEM (JSM-5410) combined with a grating monochromator (Mono CL2) to measure

  1. Properties of Cathodoluminescence for Cryogenic Applications of SiO2-based Space Observatory Optics and Coatings

    Science.gov (United States)

    Evans, Amberly; Dennison, J.R.; Wilson, Gregory; Dekany, Justin; Bowers Charles W.; Meloy, Robert; Heaney, James B.

    2013-01-01

    Disordered thin film SiO2SiOx coatings undergoing electron-beam bombardment exhibit cathodoluminescence, which can produce deleterious stray background light in cryogenic space-based astronomical observatories exposed to high-energy electron fluxes from space plasmas. As future observatory missions push the envelope into more extreme environments and more complex and sensitive detection, a fundamental understanding of the dependencies of this cathodoluminescence becomes critical to meet performance objectives of these advanced space-based observatories. Measurements of absolute radiance and emission spectra as functions of incident electron energy, flux, and power typical of space environments are presented for thin (60-200 nm) SiO2SiOx optical coatings on reflective metal substrates over a range of sample temperatures (40-400 K) and emission wavelengths (260-5000 nm). Luminescent intensity and peak wavelengths of four distinct bands were observed in UVVISNIR emission spectra, ranging from 300 nm to 1000 nm. A simple model is proposed that describes the dependence of cathodoluminescence on irradiation time, incident flux and energy, sample thickness, and temperature.

  2. Fast tomography using quasi-monochromatic undulator radiation.

    Science.gov (United States)

    Uesugi, Kentaro; Sera, Toshihiro; Yagi, Naoto

    2006-09-01

    A beamline with a helical undulator has been used without a monochromator for fast high-resolution tomographic imaging with an X-ray energy of 12.4-16.5 keV and an energy bandwidth of 2-3%. The X-ray beam was expanded with two mirrors to 12 mm x 4 mm. The X-ray field was made uniform by a diffuser. The detector pixel size was 9.9 microm x 9.9 microm. At the highest speed, a 180 degrees scan was completed in 6 s with 454 projections. Beam-hardening effects were not significant. This technique may be useful in studying time-dependent structural changes of soft materials such as polymers and biological samples.

  3. Nanometer scale correlation of optical and structural properties of individual InGaN/GaN nanorods by scanning transmission electron microscope cathodoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Marcus; Schmidt, Gordon; Veit, Peter; Petzold, Silke; Bertram, Frank; Christen, Juergen [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg (Germany); Albert, Steven; Bengoechea-Encabo, Ana Maria; Sanchez-Garcia, Miguel Angel; Calleja, Enrique [ISOM e Departamento de Ingenieria Electronica, Universidad Politecnica de Madrid (Spain)

    2013-07-01

    A potential benefit of nanorods as light emitters, aside from their very high crystal quality, relies on better light extraction efficiency as compared to thin films, because of the high surface to volume ratio. In this study we present a direct nano-scale correlation of the optical properties with the actual crystalline structure of ordered InGaN/GaN nanorods using low temperature cathodoluminescence spectroscopy in a scanning transmission electron microscope (STEM-CL). Direct comparison of the high-angle annular dark field image with the simultaneously recorded panchromatic CL mapping at 15 K reveals a weak luminescence from the bottom GaN layer. We observe the highest CL intensity in the middle of the InGaN region. The spectral position of the InGaN emission shifts continuously red from the GaN/InGaN interface (λ=409 nm) to the NR top (λ=446 nm) due to lattice pulling effects and InGaN partial decomposition. Additionally, optical active basal stacking faults in the GaN layer emitting at 366 nm can be found.

  4. Cathodoluminescence and Cross-sectional Transmission Electron Microscopy Studies for Deformation Behaviors of GaN Thin Films Under Berkovich Nanoindentation

    Directory of Open Access Journals (Sweden)

    Teng I-Ju

    2008-01-01

    Full Text Available AbstractIn this study, details of Berkovich nanoindentation-induced mechanical deformation mechanisms of metal-organic chemical-vapor deposition-derived GaN thin films have been systematic investigated with the aid of the cathodoluminescence (CL and the cross-sectional transmission electron microscopy (XTEM techniques. The multiple “pop-in” events were observed in the load-displacement (P–h curve and appeared to occur randomly by increasing the indentation load. These instabilities are attributed to the dislocation nucleation and propagation. The CL images of nanoindentation show very well-defined rosette structures with the hexagonal system and, clearly display the distribution of deformation-induced extended defects/dislocations which affect CL emission. By using focused ion beam milling to accurately position the cross-section of an indented area, XTEM results demonstrate that the major plastic deformation is taking place through the propagation of dislocations. The present observations are in support to the massive dislocations activities occurring underneath the indenter during the loading cycle. No evidence of either phase transformation or formation of micro-cracking was observed by means of scanning electron microscopy and XTEM observations. We also discuss how these features correlate with Berkovich nanoindentation produced defects/dislocations structures.

  5. Pulsed Cathodoluminescence Spectra of Solid Oxides with Low Concentrations of Optically-Active Impurities

    CERN Document Server

    Kozlov, V A; Pestovskii, N V; Petrov, A A; Savinov, S Yu; Zavartsev, Yu D; Zavertyaev, M V; Zagumenniy, A I

    2016-01-01

    Pulsed cathodoluminescence (PCL) spectra of ultra-pure SiO2, GeO2, SnO2, TiO2, La2O3, Y2O3, Sc2O3, CaCO3 powders and {\\alpha}-quartz, Ca:YVO4, LiNbO3 and Sc:LiNbO3 crystals were studied under the same experimental conditions. It was found that PCL spectra of SiO2, SnO2, GeO2, TiO2, La2O3 and CaCO3 powders contain a common band with maximum intensity at 500 nm, PCL spectra of samples Y2O3, Sc2O3, PbWO4 and Ca:YVO4 contain a common band at 490 nm and PCL spectra of LiNbO3 and Sc:LiNbO3 crystals contain a common band at 507 nm. It was found that the average intensity of the PCL spectra and position of the maximum intensity of these common bands depend on the type of a band gap transition of the material. We suppose that these common bands have the same origin in PCL spectra of all the materials studied and are related to recombination of O2--O-oxygen complexes. These complexes appear in the vicinities of anionic and cationic vacancies, where the geometry and orientation of coordination polyhedrons are violated d...

  6. Cathodoluminescence measurements on heavily boron doped homoepitaxial diamond films and their interfaces with their Ib substrates

    Science.gov (United States)

    Baron, C.; Deneuville, A.; Wade, M.; Jomard, F.; Chevallier, J.

    2006-02-01

    Heavily boron doped 1.8 to 2.4 μm thick homoepitaxial diamond films with 1.5 × 1021 cm-3 [B] 1.75 × 1021 cm-3 have been deposited directly on their (100) Ib substrates at 830 °C. Their cathodoluminescence spectra probe the controlled thicknesses from 0.28 to 2.8 μm, therefore the bulk of the films as well as their interfaces with their substrates. The bulk of these films exhibit a band with shoulders ascribed to BETO (5.036 eV), FETO (5.094 eV) and BENP (5.184 eV) excitons whose energies are downward shifted by about 180 meV in comparison with monocrystalline diamond with low [B] FETO and BENP from interfacial layers with low [B]. From their BETO to FETO ratio, their concentration of boron on isolated substitutional sites is significantly lower than their total low [B] content measured by SIMS. A tentative model is proposed to explain the characteristics of these 40 to 160 quasihomogeneous interfacial layers.

  7. Three-dimensional cathodoluminescence characterization of a semipolar GaInN based LED sample

    Science.gov (United States)

    Hocker, Matthias; Maier, Pascal; Tischer, Ingo; Meisch, Tobias; Caliebe, Marian; Scholz, Ferdinand; Mundszinger, Manuel; Kaiser, Ute; Thonke, Klaus

    2017-02-01

    A semipolar GaInN based light-emitting diode (LED) sample is investigated by three-dimensionally resolved cathodoluminescence (CL) mapping. Similar to conventional depth-resolved CL spectroscopy (DRCLS), the spatial resolution perpendicular to the sample surface is obtained by calibration of the CL data with Monte-Carlo-simulations (MCSs) of the primary electron beam scattering. In addition to conventional MCSs, we take into account semiconductor-specific processes like exciton diffusion and the influence of the band gap energy. With this method, the structure of the LED sample under investigation can be analyzed without additional sample preparation, like cleaving of cross sections. The measurement yields the thickness of the p-type GaN layer, the vertical position of the quantum wells, and a defect analysis of the underlying n-type GaN, including the determination of the free charge carrier density. The layer arrangement reconstructed from the DRCLS data is in good agreement with the nominal parameters defined by the growth conditions.

  8. Forensic discrimination of glass using cathodoluminescence and CIE LAB color coordinates: a feasibility study.

    Science.gov (United States)

    Bell, Suzanne C; Nawrocki, Heidi D; Morris, Keith B

    2009-08-10

    Cathodoluminescence (CL) spectroscopy has been shown to be useful for differentiating typical evidentiary glass samples. CL occurs when a surface is bombarded with an electron beam as in scanning electron microscopy and most of this luminescence is in the visible range. In effect, CL imparts color to colorless evidence and as a result, proven methods of forensic color analysis can be applied. In this work, spectral data dimensions were reduced to three and plotted in the CIE LAB color space. This approach allows for incorporation of uncertainties generated principally by intra-sample variation. NIST glass standards were used for method development and validation while potential case applications were studied with collections of window, consumer, and auto headlamp glasses. Using refractive index as the initial grouping variable, all of the window and consumer glasses were differentiated as were 6 of 10 automobile headlamp glasses. The potential advantages of CL include low cost instrumentation, its non-destructive nature, and ease of operation. The current limitations of CL in this context are the lack of databases and standards and the relatively low resolution of typical CL spectra.

  9. Solid state cathodoluminescence based on tris-(8-hydroxyquinoline) aluminum and its quenching mechanism

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A novel solid state cathodoluminescence(SSCL) device(the device has a structure of ITO/SiO2/Alq3/SiO2/Al) is fabricated using organic materials as the fluorescent film sandwiched between two SiO2 layers.When alternating current(AC) voltage is applied to this device,uniform emissions are observed.When the voltage is 50 V,a longer wavelength emission(522 nm) is obtained,but the shorter wavelength emission(465 nm) is dominant when the voltage is 76 V.The origins of these emissions are discussed.The interface formed between SiO2 and tris-(8-hydroquinoline) aluminum(Alq3) of SSCL device was investigated by using X-ray photoelectron spectroscopy(XPS).Analyses of the XPS spectra reveal a deep diffusion of the indium into the interface.On the other hand,the interaction between indium and Alq3 occurs at the interface and results in the formation of a carbon-oxygen-metal(In or Al) complex in the contact region.This effect causes a luminescence quenching in the SSCL device.

  10. Surface charging of phosphors and its effects on cathodoluminescence at low electron energies

    Energy Technology Data Exchange (ETDEWEB)

    Seager, C.H.; Warren, W.L.; Tallant, D.R.

    1997-05-01

    Measurements of the threshold for secondary electron emission and shifts of the carbon Auger line position have been used to deduce the surface potential of several common phosphors during irradiation by electrons in the 0.5--5.0 keV range. All of the insulating phosphors display similar behavior: the surface potential is within {+-}1 V of zero at low electron energies. However, above 2--3 kV it becomes increasingly negative, reaching hundreds of volts within 1 keV of the turn-on energy. The electron energy at which this charging begins decreases dramatically after Coulomb aging at 17 {micro}A/cm{sup 2} for 30--60 min. Measurements using coincident electron beams at low and high electron energies to control the surface potential were made to investigate the dependence of the cathodoluminescence (CL) process on charging. Initially, the CL from the two beams is identical to the sum of the separate beam responses, but after Coulomb aging large deviations from this additivity are observed. These results indicate that charging has important, detrimental effects on CL efficiency after prolonged e-beam irradiation. Measurements of the electron energy dependence of the CL efficiency before and after Coulomb aging will also be presented, and the implications of these data on the physics of the low-voltage CL process will be discussed.

  11. Scanning Electron Microscope-Cathodoluminescence Analysis of Rare-Earth Elements in Magnets.

    Science.gov (United States)

    Imashuku, Susumu; Wagatsuma, Kazuaki; Kawai, Jun

    2016-02-01

    Scanning electron microscope-cathodoluminescence (SEM-CL) analysis was performed for neodymium-iron-boron (NdFeB) and samarium-cobalt (Sm-Co) magnets to analyze the rare-earth elements present in the magnets. We examined the advantages of SEM-CL analysis over conventional analytical methods such as SEM-energy-dispersive X-ray (EDX) spectroscopy and SEM-wavelength-dispersive X-ray (WDX) spectroscopy for elemental analysis of rare-earth elements in NdFeB magnets. Luminescence spectra of chloride compounds of elements in the magnets were measured by the SEM-CL method. Chloride compounds were obtained by the dropwise addition of hydrochloric acid on the magnets followed by drying in vacuum. Neodymium, praseodymium, terbium, and dysprosium were separately detected in the NdFeB magnets, and samarium was detected in the Sm-Co magnet by the SEM-CL method. In contrast, it was difficult to distinguish terbium and dysprosium in the NdFeB magnet with a dysprosium concentration of 1.05 wt% by conventional SEM-EDX analysis. Terbium with a concentration of 0.02 wt% in an NdFeB magnet was detected by SEM-CL analysis, but not by conventional SEM-WDX analysis. SEM-CL analysis is advantageous over conventional SEM-EDX and SEM-WDX analyses for detecting trace rare-earth elements in NdFeB magnets, particularly dysprosium and terbium.

  12. Biosynthesis of cathodoluminescent zinc oxide replicas using butterfly (Papilio paris) wing scales as templates

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Wang [State Key Lab of Metal Matrix Composites, Shanghai Jiao Tong University, 200240, Shanghai (China); Zhang Di [State Key Lab of Metal Matrix Composites, Shanghai Jiao Tong University, 200240, Shanghai (China)], E-mail: zhangdi@sjtu.edu.cn; Fan Tongxiang; Ding Jian; Gu Jiajun [State Key Lab of Metal Matrix Composites, Shanghai Jiao Tong University, 200240, Shanghai (China); Guo Qixin; Ogawa, Hiroshi [Department of Electrical and Electronic Engineering, Saga University, Saga 840-8502 (Japan)

    2009-01-01

    Papilio paris butterflies have an iridescent blue color patch on their hind wings which is visible over a wide viewing angle. Optical and scanning electron microscopy observations of scales from the wings show that the blue color scales have very different microstructure to the matt black ones which also populate the wings. Scanning electron micrographs of the blue scales show that their surfaces comprise a regular two-dimensional array of concavities. By contrast the matt black scales have fine, sponge-like structure, between the ridges and the cross ribs in the scales. Using both types of scale as bio-templates, we obtain zinc oxide (ZnO) replicas of the microstructures of the original scales. Room temperature (T = 300 K) cathodoluminescence spectra of these ZnO replicas have also been studied. Both spectra show a similar sharp near-band-edge emission, but have different green emission, which we associate with the different microstructures of the ZnO replicas.

  13. Photo and cathodoluminescence characteristics of dysprosium doped yttrium oxide nanoparticles prepared by Polyol method

    Energy Technology Data Exchange (ETDEWEB)

    Balderas-Xicohténcatl, R., E-mail: rbalderas@fis.cinvestav.mx [Centro de Investigación y de Estudios Avanzados-IPN, Departamento de Física, Apdo, Postal 14-470, Del. Gustavo A. Madero, C.P. 07360, México, D.F. (Mexico); Martínez-Martínez, R. [Instituto de Física y Matemáticas, Universidad Tecnológica de la Mixteca, Carretera a Acatlima Km. 2.5, Huajuapan de León, Oaxaca 69000 (Mexico); Rivera-Alvarez, Z.; Santoyo-Salazar, J.; Falcony, C. [Centro de Investigación y de Estudios Avanzados-IPN, Departamento de Física, Apdo, Postal 14-470, Del. Gustavo A. Madero, C.P. 07360, México, D.F. (Mexico)

    2014-02-15

    The luminescent characteristics of Dy{sup 3+}-doped Y{sub 2}O{sub 3} nanopowders synthesized using the polyol method are reported. The Y{sub 2}O{sub 3} nanoparticles presented a cubic phase crystalline structure of Y{sub 2}O{sub 3} after an annealing treatment in oxygen ambient at temperatures above 600 °C. The averaged crystallite size determined from the X-ray diffraction peaks width was in the 20–32 nm range depending on the annealing temperature. Scanning and transmission electron microscopy studies indicate the formation of nanoparticle aggregates up to 175 nm in diameter. Photoluminescence and cathodoluminescence measurements show a predominant emission at 573 nm, which is attributed to the {sup 4}F{sub 9/2}→{sup 6}H{sub 13/2} of the Dy{sup 3+} ion. The luminescence emission dependence with the dopant concentration and post-annealing temperatures is discussed. -- Highlights: • Nanoparticles of Y{sub 2}O{sub 3}:Dy{sup 3+} have been successfully synthesized by the polyol method. • XRD shows a grain size from 20 to 32 nm which is in agreement with SEM and TEM. • Electronic micrographs indicate the formation agglomerates of ∼175 nm. • The method used in the synthesis is industrial scalable and a low cost. • CL emission is observed at naked eye.

  14. Towards a Monochromatization Scheme for Direct Higgs Production at FCC-ee

    CERN Document Server

    Valdivia Garcia, Marco Alan; Zimmermann, Frank

    2016-01-01

    Direct Higgs production in e+e− collisions at the FCC is of interest if the centre-of-mass energy spread can be reduced by at least an order of magnitude. A monochromatization scheme, to accomplish this, can be realized with horizontal dispersion of opposite sign for the two colliding beams at the interaction point (IP). We recall historical approaches to monochromatization, then derive a set of IP parameters which would provide the required performance in FCC e+e− collisions at 62.5 GeV beam energy, compare these with the baseline optics parameters at neighbouring energies (45.6 and 80 GeV), comment on the effect of beamstrahlung, and indicate the modifications of the FCC-ee final-focus optics needed to obtain the required parameters.

  15. Monochromatization of femtosecond XUV light pulses with the use of reflection zone plates.

    Science.gov (United States)

    Metje, Jan; Borgwardt, Mario; Moguilevski, Alexandre; Kothe, Alexander; Engel, Nicholas; Wilke, Martin; Al-Obaidi, Ruba; Tolksdorf, Daniel; Firsov, Alexander; Brzhezinskaya, Maria; Erko, Alexei; Kiyan, Igor Yu; Aziz, Emad F

    2014-05-05

    We report on a newly built laser-based tabletop setup which enables generation of femtosecond light pulses in the XUV range employing the process of high-order harmonic generation (HHG) in a gas medium. The spatial, spectral, and temporal characteristics of the XUV beam are presented. Monochromatization of XUV light with minimum temporal pulse distortion is the central issue of this work. Off-center reflection zone plates are shown to be advantageous when selection of a desired harmonic is carried out with the use of a single optical element. A cross correlation technique was applied to characterize the performance of the zone plates in the time domain. By using laser pulses of 25 fs length to pump the HHG process, a pulse duration of 45 fs for monochromatized harmonics was achieved in the present setup.

  16. Monochromatic wavelength dispersive x-ray fluorescence providing sensitive and selective detection of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Havrilla, George J [Los Alamos National Laboratory; Collins, Michael L [Los Alamos National Laboratory; Montoya, Velma M [Los Alamos National Laboratory; Chen, Zewu [XOS; Wei, Fuzhong [XOS

    2010-01-01

    Monochromatic wavelength dispersive X-ray fluorescence (MWDXRF) is a sensitive and selective method for elemental compositional analyses. The basis for this instrumental advance is the doubly curved crystal (DCC) optic. Previous work has demonstrated the feasibility of sensitive trace element detection for yttrium as a surrogate for curium in aqueous solutions. Additional measurements have demonstrated similar sensitivity in several different matrix environments which attests to the selectivity of the DCC optic as well as the capabilities of the MWDXRF concept. The objective of this effort is to develop an improved Pu characterization method for nuclear fuel reprocessing plants. The MWDXRF prototype instrument is the second step in a multi-year effort to achieve an improved Pu assay. This work will describe a prototype MWDXRF instrument designed for uranium detection and characterization. The prototype consists of an X-ray tube with a rhodium anode and a DCC excitation optic incorporated into the source. The DCC optic passes the RhK{alpha} line at 20.214 keV for monochromatic excitation of the sample. The source is capable of 50 W power at 50 kV and 1.0 mA operation. The x-ray emission from the sample is collected by a DCC optic set at the UL{alpha} line of 13.613 keV. The collection optic transmits the UL{alpha} x-rays to the silicon drift detector. The x-ray source, sample, collection optic and detector are all mounted on motion controlled stages for the critical alignment of these components. The sensitivity and selectivity of the instrument is obtained through the monochromatic excitation and the monochromatic detection. The prototype instrument performance has a demonstrated for sensitivity for uranium detection of around 2 ppm at the current state of development. Further improvement in sensitivity is expected with more detailed alignment.

  17. Feasibility of Strong and Quasi-Monochromatic Gamma-Ray Generation by the Laser Compton Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jiyoung; Rehman, Haseeb ur; Kim, Yonghee [KAIST, Daejeon (Korea, Republic of)

    2015-10-15

    This is because LCS γ-rays are energy-tunable, quasi-monochromatic, and beam-like. The photon intensity of the mono-chromatic LCS gamma-ray should be high or strong for efficient and high transmutation rate. It was recently reported that a so-called energy-recovery linac system is able to produce a very high-intensity LCS photons in the order of approximately 1013 photons/s economically. It however did not evaluate quality of the LCS photon beam although a quasi-monoenergetic LCS beam is of huge importance in the photo-nuclear transmutation reactions. It is upon this observation that this paper was prepared. Specifically, this work attempts to quantify intensity of the quasi-monochromatic LCS beam from the said linac system. In addition, this paper aims to discuss general characteristics of the LCS photon, and possible approaches to increase its intensity. This paper presents essential characteristics of the laser Compton scattering (LCS) in terms of its photon energy, cross-section and photon intensity. By using different combinations of electron energy, laser energy and scattering angle, we can effectively generate high-intensity and highly-chromatic LCS gamma-rays. Our preliminary analyses indicate that, in view of Compton cross-section, higher-energy photon can be better generated by increasing the electron energy rather than increasing the laser energy. However, in order to maximize the intensity of monochromatic beam, the laser energy should be maximized for a targeted LCS photon energy.

  18. In-ovo monochromatic green light photostimulation enhances embryonic somatotropic axis activity.

    Science.gov (United States)

    Dishon, L; Avital-Cohen, N; Malamud, D; Heiblum, R; Druyan, S; Porter, T E; Gumulka, M; Rozenboim, I

    2017-06-01

    Previous studies demonstrated that in ovo photostimulation with monochromatic green light increases body weight and accelerates muscle development in broilers. The mechanism in which in ovo photostimulation accelerates growth and muscle development is not clearly understood. The objective of the current study was to define development of the somatotropic axis in the broiler embryo associated with in ovo green light photostimulation. Two-hundred-forty fertile broiler eggs were divided into 2 groups. The first group was incubated under intermittent monochromatic green light using light-emitting diode (LED) lamps with an intensity of 0.1 W\\m2 at shell level, and the second group was incubated under dark conditions and served as control. In ovo green light photostimulation increased plasma growth hormone (GH) and prolactin (PRL) levels, as well as hypothalamic growth hormone releasing hormone (GHRH), liver growth hormone receptor (GHR), and insulin-like growth factor-1 (IGF-1) mRNA levels. The in ovo photostimulation did not, however, increase embryo's body weight, breast muscle weight, or liver weight. The results of this study suggest that stimulation with monochromatic green light during incubation increases somatotropic axis expression, as well as plasma prolactin levels, during embryonic development. © 2017 Poultry Science Association Inc.

  19. Dichromatic and monochromatic laser radiation effects on survival and morphology of Pantoea agglomerans

    Science.gov (United States)

    Thomé, A. M. C.; Souza, B. P.; Mendes, J. P. M.; Soares, L. C.; Trajano, E. T. L.; Fonseca, A. S.

    2017-05-01

    Despite the beneficial effects of low-level lasers on wound healing, their application for treatment of infected injuries is controversial because low-level lasers could stimulate bacterial growth exacerbating the infectious process. Thus, the aim of this work was to evaluate in vitro effects of low-level lasers on survival, morphology and cell aggregation of Pantoea agglomerans. P. agglomerans samples were isolated from human pressure injuries and cultures were exposed to low-level monochromatic and simultaneous dichromatic laser radiation to study the survival, cell aggregation, filamentation and morphology of bacterial cells in exponential and stationary growth phases. Fluence, wavelength and emission mode were those used in therapeutic protocols for wound healing. Data show no changes in morphology and cell aggregation, but dichromatic laser radiation decreased bacterial survival in exponential growth phase and monochromatic red and infrared lasers increased bacterial survival at the same fluence. Simultaneous dichromatic laser radiation induces biological effects that differ from those induced by monochromatic laser radiation and simultaneous dichromatic laser could be the option for treatment of infected pressure injuries by Pantoea agglomerans.

  20. Melatonin modulates monochromatic light-induced GHRH expression in the hypothalamus and GH secretion in chicks.

    Science.gov (United States)

    Zhang, Liwei; Cao, Jing; Wang, Zixu; Dong, Yulan; Chen, Yaoxing

    2016-04-01

    To study the mechanism by which monochromatic lights affect the growth of broilers, a total of 192 newly hatched broilers, including the intact, sham-operated and pinealectomy groups, were exposed to white light (WL), red light (RL), green light (GL) and blue light (BL) using a light-emitting diode (LED) system for 2 weeks. The results showed that the GHRH-ir neurons were distributed in the infundibular nucleus (IN) of the chick hypothalamus. The mRNA and protein levels of GHRH in the hypothalamus and the plasma GH concentrations in the chicks exposed to GL were increased by 6.83-31.36%, 8.71-34.52% and 6.76-9.19% compared to those in the chicks exposed to WL (P=0.022-0.001), RL (P=0.002-0.000) and BL (P=0.290-0.017) in the intact group, respectively. The plasma melatonin concentrations showed a positive correlation with the expression of GHRH (r=0.960) and the plasma GH concentrations (r=0.993) after the various monochromatic light treatments. After pinealectomy, however, these parameters decreased and there were no significant differences between GL and the other monochromatic light treatments. These findings suggest that melatonin plays a critical role in GL illumination-enhanced GHRH expression in the hypothalamus and plasma GH concentrations in young broilers. Copyright © 2016 Elsevier GmbH. All rights reserved.

  1. Excitation of monochromatic and stable electron acoustic wave by two counter-propagating laser beams

    Science.gov (United States)

    Xiao, C. Z.; Liu, Z. J.; Zheng, C. Y.; He, X. T.

    2017-07-01

    The undamped electron acoustic wave is a newly-observed nonlinear electrostatic plasma wave and has potential applications in ion acceleration, laser amplification and diagnostics due to its unique frequency range. We propose to make the first attempt to excite a monochromatic and stable electron acoustic wave (EAW) by two counter-propagating laser beams. The matching conditions relevant to laser frequencies, plasma density, and electron thermal velocity are derived and the harmonic effects of the EAW are excluded. Single-beam instabilities, including stimulated Raman scattering and stimulated Brillouin scattering, on the excitation process are quantified by an interaction quantity, η =γ {τ }B, where γ is the growth rate of each instability and {τ }B is the characteristic time of the undamped EAW. The smaller the interaction quantity, the more successfully the monochromatic and stable EAW can be excited. Using one-dimensional Vlasov-Maxwell simulations, we excite EAW wave trains which are amplitude tunable, have a duration of thousands of laser periods, and are monochromatic and stable, by carefully controlling the parameters under the above conditions.

  2. Dark Matter Decay to a Photon and a Neutrino: the Double Monochromatic Smoking Gun Scenario

    CERN Document Server

    Aisati, Chaïmae El; Hambye, Thomas; Scarna, Tiziana

    2015-01-01

    In the energy range from few TeV to 25 TeV, upper bounds on the dark matter decay rate into high energy monochromatic neutrinos have recently become comparable to those on monochromatic gamma-ray lines. This implies clear possibilities of a future double "smoking-gun" evidence for the dark matter particle, from the observation of both a gamma and a neutrino line at the same energy. In particular, we show that a scenario where both lines are induced from the same dark matter particle decay leads to correlations that can already be tested. We study this "double monochromatic" scenario by considering the complete list of lowest dimensional effective operators that could induce such a decay. Furthermore, we argue that, on top of lines from decays into two-body final states, three-body final states can also be highly relevant. In addition to producing a distinct hard photon spectrum, three-body final states also produce a line-like feature in the neutrino spectrum that can be searched for by neutrino telescopes.

  3. Implementation of dual-energy technique for virtual monochromatic and linearly mixed CBCTs

    Energy Technology Data Exchange (ETDEWEB)

    Li Hao; Giles, William; Ren Lei; Bowsher, James; Yin Fangfang [Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710 (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2012-10-15

    Purpose: To implement dual-energy imaging technique for virtual monochromatic (VM) and linearly mixed (LM) cone beam CTs (CBCTs) and to demonstrate their potential applications in metal artifact reduction and contrast enhancement in image-guided radiation therapy (IGRT). Methods: A bench-top CBCT system was used to acquire 80 kVp and 150 kVp projections, with an additional 0.8 mm tin filtration. To implement the VM technique, these projections were first decomposed into acrylic and aluminum basis material projections to synthesize VM projections, which were then used to reconstruct VM CBCTs. The effect of VM CBCT on the metal artifact reduction was evaluated with an in-house titanium-BB phantom. The optimal VM energy to maximize contrast-to-noise ratio (CNR) for iodine contrast and minimize beam hardening in VM CBCT was determined using a water phantom containing two iodine concentrations. The LM technique was implemented by linearly combining the low-energy (80 kVp) and high-energy (150 kVp) CBCTs. The dose partitioning between low-energy and high-energy CBCTs was varied (20%, 40%, 60%, and 80% for low-energy) while keeping total dose approximately equal to single-energy CBCTs, measured using an ion chamber. Noise levels and CNRs for four tissue types were investigated for dual-energy LM CBCTs in comparison with single-energy CBCTs at 80, 100, 125, and 150 kVp. Results: The VM technique showed substantial reduction of metal artifacts at 100 keV with a 40% reduction in the background standard deviation compared to a 125 kVp single-energy scan of equal dose. The VM energy to maximize CNR for both iodine concentrations and minimize beam hardening in the metal-free object was 50 keV and 60 keV, respectively. The difference of average noise levels measured in the phantom background was 1.2% between dual-energy LM CBCTs and equivalent-dose single-energy CBCTs. CNR values in the LM CBCTs of any dose partitioning are better than those of 150 kVp single-energy CBCTs. The

  4. 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

  5. Distinguishing the Asian dust sources based on cathodoluminescence analysis of single quartz grain

    Science.gov (United States)

    Nagashima, K.; Nishido, H.; Kayama, M.; Tada, R.; Isozaki, Y.; Sun, Y.; Igarashi, Y.

    2009-12-01

    Numerous tracers, such as mineralogical component, strontium (87Sr/86Sr) and neodymium (eNd(0)) isotopes (Liu et al., 1994; Biscaye et al.,1997; Bory et al., 2002, 2003; Kanayama et al., 2002, 2005), rare earth element composition (e.g., Svensson et al., 2000), oxygen isotope (Mizota et al., 1992; Hou et al., 2003) and ESR intensity of quartz (Ono et al., 1998; Sun et al., 2007), have been investigated to discriminate source areas of Asian dust. However, these analyses need large volume of samples (mostly more than 10 mg) and the applications to the dust samples are limited. Then, here we developed a provenance-tracing method by using a cathodoluminescence (CL) spectral of “single” quartz grain for applying it to small volume of aeolian dust samples, such as aeolian dust in the ice cores and marine sediments with the location of long distance from the Asian deserts. CL is the emission from a material which is excited by electron beam. Since CL spectroscopy and microscopy provide information on the existence and distribution of defects and trace elements in minerals, CL analyses have potential to characterize dust-source areas. CL spectra of quartz have been demonstrated to show different patterns between the quartz from hydrothermal, plutonic, volcanic and metamorphic origins (e.g., Zinkernagel, 1978; Götze et al., 2001), suggesting the spectra reflect the condition of the quartz formation and the local environment. Then, here we conducted CL spectral analysis of silt size quartz in the surface samples from the major Asian deserts, such as the Taklimakan Desert and Gobi Desert in southern Mongolia (hereafter Mongolian Gobi). CL spectra were measured in the areas of approximately 4 micron square for each quartz grain by a Scanning Electron Microscope-Cathodoluminescence (SEM-CL) at the Okayama University of Science, a SEM (Jeol: JSM-5410) attached with a grating monochromator (Oxford Instruments: Mono CL2), where EDS system can be used in combination with SEM

  6. Monochromatic Minibeams Radiotherapy: From Healthy Tissue-Sparing Effect Studies Toward First Experimental Glioma Bearing Rats Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Deman, Pierre [INSERM, Grenoble (France); Universite Joseph Fourier, Institut des Neurosciences, Grenoble (France); European Synchrotron Radiation Facility, Grenoble (France); Vautrin, Mathias [INSERM, Grenoble (France); Universite Joseph Fourier, Institut des Neurosciences, Grenoble (France); European Synchrotron Radiation Facility, Grenoble (France); DOSIsoft, Cachan (France); Edouard, Magali [INSERM, Grenoble (France); Universite Joseph Fourier, Institut des Neurosciences, Grenoble (France); European Synchrotron Radiation Facility, Grenoble (France); Stupar, Vasile [INSERM, Grenoble (France); Universite Joseph Fourier, Institut des Neurosciences, Grenoble (France); Bobyk, Laure; Farion, Regine [INSERM, Grenoble (France); Universite Joseph Fourier, Institut des Neurosciences, Grenoble (France); European Synchrotron Radiation Facility, Grenoble (France); Elleaume, Helene [INSERM, Grenoble (France); Universite Joseph Fourier, Institut des Neurosciences, Grenoble (France); European Synchrotron Radiation Facility, Grenoble (France); Grenoble University Hospital, Grenoble (France); Remy, Chantal; Barbier, Emmanuel L. [INSERM, Grenoble (France); Universite Joseph Fourier, Institut des Neurosciences, Grenoble (France); Esteve, Francois [INSERM, Grenoble (France); Universite Joseph Fourier, Institut des Neurosciences, Grenoble (France); European Synchrotron Radiation Facility, Grenoble (France); Grenoble University Hospital, Grenoble (France); Adam, Jean-Francois, E-mail: adam@esrf.fr [INSERM, Grenoble (France); Universite Joseph Fourier, Institut des Neurosciences, Grenoble (France); European Synchrotron Radiation Facility, Grenoble (France); Grenoble University Hospital, Grenoble (France)

    2012-03-15

    Purpose: The purpose of this study was to evaluate high-dose single fraction delivered with monochromatic X-rays minibeams for the radiotherapy of primary brain tumors in rats. Methods and Materials: Two groups of healthy rats were irradiated with one anteroposterior minibeam incidence (four minibeams, 123 Gy prescribed dose at 1 cm depth in the brain) or two interleaved incidences (54 Gy prescribed dose in a 5 Multiplication-Sign 5 Multiplication-Sign 4.8 mm{sup 3} volume centered in the right hemisphere), respectively. Magnetic resonance imaging (MRI) follow-up was performed over 1 year. T2-weighted (T2w) images, apparent diffusion coefficient (ADC), and blood vessel permeability maps were acquired. F98 tumor bearing rats were also irradiated with interleaved minibeams to achieve a homogeneous dose of 54 Gy delivered to an 8 Multiplication-Sign 8 Multiplication-Sign 7.8 mm{sup 3} volume centered on the tumor. Anatomic and functional MRI follow-up was performed every 10 days after irradiation. T2w images, ADC, and perfusion maps were acquired. Results: All healthy rats were euthanized 1 year after irradiation without any clinical alteration visible by simple examination. T2w and ADC measurements remain stable for the single incidence irradiation group. Localized Gd-DOTA permeability, however, was observed 9 months after irradiation for the interleaved incidences group. The survival time of irradiated glioma bearing rats was significantly longer than that of untreated animals (49 {+-} 12.5 days versus 23.3 {+-} 2 days, p < 0.001). The tumoral cerebral blood flow and blood volume tend to decrease after irradiation. Conclusions: This study demonstrates the sparing effect of minibeams on healthy tissue. The increased life span achieved for irradiated glioma bearing rats was similar to the one obtained with other radiotherapy techniques. This experimental tumor therapy study shows the feasibility of using X-ray minibeams with high doses in brain tumor radiotherapy.

  7. Cathodoluminescence emission of REE (Dy, Pr and Eu) doped LaAlO3 phosphors

    Science.gov (United States)

    Boronat, C.; Rivera, T.; Garcia-Guinea, J.; Correcher, V.

    2017-01-01

    Luminescence emission from rare earth (REE) ions doped materials are being of interest since can be employed as scintillators, catalysts, battery and magnetic materials, etc. We herein report on the preliminary results obtained from the cathodoluminescence (CL) properties of undoped LaAlO3 (LAO) and LaAlO3: REE3+ (REE=Dy3+, Pr3+ and Eu3+) samples synthesized by a sol-gel process based on the Pechini's method with a spray-drying technique. The samples, previously characterized by means of Environmental Scanning Electron Microscopy and Energy Dispersive X-Ray Analysis Spectrometry, display CL spectra with well-defined peaks that could specifically be associated with the LAO structure (in the range of 300-450 nm) and point defects (from 450 to 800 nm) spectral regions. The observed wavebands are as follows: (i) 480 and 570 from the Dy-doped LAO correspond respectively to 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions, (ii) 490-638 from the Pr-doped LAO is linked to 3P0→3H4, 1D2→3H4 transitions and (iii) 590 and 620 where the dopant Eu3+ gives rise to 5D0→7F1 and 5D0→7F2 transitions and (iv) a UV-blue broad band is associated with NBHOC in undoped LAO. Such emissions are due to the presence of the 4f electrons of rare earth ions that are shielded by the outer 5s and 5p electrons, the intra-4f emission spectra of REE that induce sharp and narrow wavebands.

  8. Cathodoluminescence and green-thermoluminescence response of CaSO{sub 4}:Dy,P films

    Energy Technology Data Exchange (ETDEWEB)

    Roman-Lopez, J., E-mail: holand_jeos@hotmail.com [CICATA-IPN, Legaria 694, D.F. 11500, Mexico, CIEMAT, Av., Complutense 22, Madrid 28040 (Spain); Correcher, V. [CIEMAT, Av., Complutense 22, Madrid 28040 (Spain); Garcia-Guinea, J. [Museo Nacional de Ciencias Naturales (CSIC), Jose Gutierrez Abascal 2, Madrid 28006 (Spain); Rivera, T.; Lozano, I.B. [CICATA-IPN, Legaria 694, D.F. 11500 (Mexico)

    2013-03-15

    We herein report on the cathodoluminescence (CL) and green-thermoluminescence (TL) emission of CaSO{sub 4}:Dy,P films deposited by the spray pyrolysis method at different temperatures. The samples have been previously structurally and chemically characterized by means of Raman spectroscopy and energy dispersive spectroscopy (EDS). The CL spectra show (i) a broad emission band centered at 374 nm that corresponds to the intrinsic emission of (SO{sub 4}){sup 2-} and (ii) emission bands centered on 486, 574, 668, 758 nm assigned to the electronic transitions of the Dy{sup 3+} ions. The TL glow curves of the films showed three groups of components peaked at around of 98, 152 and 300 Degree-Sign C that exhibit a gradual and progressively linear shifting of the T{sub max} as function of T{sub stop}. This TL behavior is related to a continuum in the trap distribution associated with general or multi-order kinetics and involving continuous processes of trapping-detrapping. The activation energy in the range of 0.97-1.53 eV has been estimated using the initial rise method. - Highlights: Black-Right-Pointing-Pointer The CaSO{sup 4}:Dy,P films were prepared by using the ultrasonic spray pyrolysis method. Black-Right-Pointing-Pointer Luminescence spectra of the CaSO{sub 4}:Dy,P films display the emission bands of the ions (SO{sub 4}){sup 2-} and Dy{sup 3+}. Black-Right-Pointing-Pointer The CaSO{sub 4}:Dy,P films were irradiated with a {sup 90}Sr/{sup 90}Y beta source. Black-Right-Pointing-Pointer The TL intensity of the films depends on the temperature of deposit.

  9. Study of coal and graphite specimens by means of Raman and cathodoluminescence

    Science.gov (United States)

    Kostova, Irena; Tormo, Laura; Crespo-Feo, Elena; Garcia-Guinea, Javier

    2012-06-01

    The weak luminescence shown by coals has been attributed to accessorial minerals and poly-nuclear aromatic hydrocarbons, such as exinite, vitrinite or inertinite, while the luminescence quenching has been found in asphaltenes produced by coal hydrogenation or in pyridine extracts. Nowadays, the spatial resolution and the improved luminescence efficiency of the modern spectrometers allow some details of the luminescent emission centers to be explained. We have selected museum historical coal specimens with different rank, i.e., peat, lignite, sub-bituminous, bituminous, and anthracite to be analyzed by their spectra from cathodoluminescence probe (CL) of an environmental scanning electron microscopy (ESEM), with an energy dispersive spectrometry analyzer (EDS). Additional analytical controls were also performed by X-ray diffraction (XRD), X-ray fluorescence (XRF) and Raman spectrometries. We conclude that coals may display different luminescence emission features coming from several different sources, as follows: (i) broadband of intense luminescence from polynuclear aromatic hydrocarbons, (ii) weakly visible broadband luminescence attributed to band-tail states caused by variations in the energy gap of individual sp2 carbon clusters, which are different in size and/or shape, (iii) silicate impurities causing the common luminescence peak at 325 nm observed in coals. This peak is due to non-bridging oxygen hole centres (tbnd Sisbnd Orad ) probably generated by precursor Sisbnd Osbnd C species formed by tbnd Sisbnd Orad defects and carbon atoms; (iv) a 710 nm CL emission commonly detected also in wood and ivory, which has been correlated with hydrocarbon groups of chlorophyll or lignine. Coals are very complex rocks, composed by both organic and inorganic phases with variable and complex spectra. More analyses are necessary and carbonaceous standards of graphite, silicon carbide, stuffed carbon silica and diamond at variable experimental conditions have to be

  10. Long-Term Cathodoluminescent Characterization of Thin-Film Oxide Phosphors in a Wide Range of Electron Excitation Densities

    Energy Technology Data Exchange (ETDEWEB)

    Bondar, V D; Felter, T E; Hunt, C E; Dubov, Y G; Chakhovskoi, A G

    2001-05-06

    Long-term processes of cathodoluminescence degradation of thin film phosphors Zn{sub 2}SiO{sub 4}:Ti and Zn{sub 2}GeO{sub 4}:Mn were investigated in a wide range of e-beam energies, current and power densities. The time dependencies describing decreasing of emission intensity have been found. At high-level densities of e-beam irradiation the specific behavior of long-term degradation processes was observed, which is characteristic with rapid degradation at initial stage and slow consequent decrease of intensity. The most probable mechanisms responsible for long-term processes of degradation in investigated phosphors are proposed.

  11. Long-Term Cathodoluminescent Characterization of Thin-Film Oxide Phosphors in a Wide Range of Electron Excitation Densities

    Energy Technology Data Exchange (ETDEWEB)

    Bondar, V D; Felter, T E; Hunt, C E; Dubov, Y G; Chakhovskoy, A G

    2001-04-09

    Long-term processes of cathodoluminescence degradation of thin film phosphors Zn{sub 2}SiO{sub 4}:Ti and Zn{sub 2}GeO{sub 4}:Mn were investigated in a wide range of e-beam energies, current and power densities. The time dependencies describing decreasing of emission intensity have been found. At high-level densities of e-beam irradiation the specific behavior of long-term degradation processes was observed, which is characteristic with rapid degradation at initial stage and slow consequent decrease of intensity. The most probable mechanisms responsible for long-term processes of degradation in investigated phosphors are proposed.

  12. Low luminance/eyes closed and monochromatic stimulations reduce variability of flash visual evoked potential latency

    Directory of Open Access Journals (Sweden)

    Senthil Kumar Subramanian

    2013-01-01

    Full Text Available Context: Visual evoked potentials are useful in investigating the physiology and pathophysiology of the human visual system. Flash visual evoked potential (FVEP, though technically easier, has less clinical utility because it shows great variations in both latency and amplitude for normal subjects. Aim: To study the effect of eye closure, low luminance, and monochromatic stimulation on the variability of FVEPs. Subjects and Methods: Subjects in self-reported good health in the age group of 18-30 years were divided into three groups. All participants underwent FVEP recording with eyes open and with white light at 0.6 J luminance (standard technique. Next recording was done in group 1 with closed eyes, group 2 with 1.2 and 20 J luminance, and group 3 with red and blue lights, while keeping all the other parameters constant. Two trials were given for each eye, for each technique. The same procedure was repeated at the same clock time on the following day. Statistical Analysis: Variation in FVEP latencies between the individuals (interindividual variability and the variations within the same individual for four trials (intraindividual variability were assessed using coefficient of variance (COV. The technique with lower COV was considered the better method. Results: Recording done with closed eyes, 0.6 J luminance, and monochromatic light (blue > red showed lower interindividual and intraindividual variability in P2 and N2 as compared to standard techniques. Conclusions: Low luminance flash stimulations and monochromatic light will reduce FVEP latency variability and may be clinically useful modifications of FVEP recording technique.

  13. Source mechanics for monochromatic icequakes produced during iceberg calving at Columbia Glacier, AK

    Science.gov (United States)

    O'Neel, Shad; Pfeffer, W.T.

    2007-01-01

    Seismograms recorded during iceberg calving contain information pertaining to source processes during calving events. However, locally variable material properties may cause signal distortions, known as site and path effects, which must be eliminated prior to commenting on source mechanics. We applied the technique of horizontal/vertical spectral ratios to passive seismic data collected at Columbia Glacier, AK, and found no dominant site or path effects. Rather, monochromatic waveforms generated by calving appear to result from source processes. We hypothesize that a fluid-filled crack source model offers a potential mechanism for observed seismograms produced by calving, and fracture-processes preceding calving.

  14. Directional and monochromatic thermal emitter from epsilon-near-zero conditions in semiconductor hyperbolic metamaterials

    Science.gov (United States)

    Campione, Salvatore; Marquier, Francois; Hugonin, Jean-Paul; Ellis, A. Robert; Klem, John F.; Sinclair, Michael B.; Luk, Ting S.

    2016-01-01

    The development of novel thermal sources that control the emission spectrum and the angular emission pattern is of fundamental importance. In this paper, we investigate the thermal emission properties of semiconductor hyperbolic metamaterials (SHMs). Our structure does not require the use of any periodic corrugation to provide monochromatic and directional emission properties. We show that these properties arise because of epsilon-near-zero conditions in SHMs. The thermal emission is dominated by the epsilon-near-zero effect in the doped quantum wells composing the SHM. Furthermore, different properties are observed for s and p polarizations, following the characteristics of the strong anisotropy of hyperbolic metamaterials.

  15. Enhancing monochromatic multipole emission by a subwavelength enclosure of degenerate Mie resonances

    KAUST Repository

    Zhao, Jiajun

    2017-07-06

    Sound emission is inefficient at low frequencies as limited by source size. This letter presents enhancing emission of monochromatic monopole and multipole sources by enclosing the source with a subwavelength circular enclosure filled of an anisotropic material of a low radial sound speed. The anisotropy is associated with an infinite tangential density along the azimuth. Numerical simulations show that emission gain is produced at frequencies surrounding degenerate Mie resonant frequencies of the enclosure, and meanwhile the radiation directivity pattern is well preserved. The degeneracy is theoretically analyzed. A realization of the material is suggested by using a space-coiling structure.

  16. Response of vegetable organisms to quasi-monochromatic light of different duration, intensity and wavelength

    Energy Technology Data Exchange (ETDEWEB)

    Budagovsky, A V; Solovykh, N V [I.V.Michurin All-Russian Recearch Institute of Fruit Crops Genetics and Breeding (Russian Federation); Budagovskaya, O N [I.V.Michurin All-Russia Research and Development Institute of Gardening, Michurinsk, Tambov region (Russian Federation); Budagovsky, I A [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2015-04-30

    By the example of vegetable organisms differing in structure and functional properties it is shown that their response to the action of quasi-monochromatic light from laser sources does not obey the Bunsen – Roscoe dose law. The dependence of biological effect on the irradiation time has the multimodal (multiextremal) form with alternating maxima and minima of the stimulating effect. Such a property manifests itself in the spectral ranges, corresponding to photoinduced conversion of chromoproteins of photocontrol systems and is probably related to the cyclic variations of metabolic activity in vegetable cells. (biophotonics)

  17. Directional and monochromatic thermal emitter from epsilon-near-zero conditions in semiconductor hyperbolic metamaterials

    Science.gov (United States)

    Campione, Salvatore; Marquier, Francois; Hugonin, Jean-Paul; Ellis, A. Robert; Klem, John F.; Sinclair, Michael B.; Luk, Ting S.

    2016-10-01

    The development of novel thermal sources that control the emission spectrum and the angular emission pattern is of fundamental importance. In this paper, we investigate the thermal emission properties of semiconductor hyperbolic metamaterials (SHMs). Our structure does not require the use of any periodic corrugation to provide monochromatic and directional emission properties. We show that these properties arise because of epsilon-near-zero conditions in SHMs. The thermal emission is dominated by the epsilon-near-zero effect in the doped quantum wells composing the SHM. Furthermore, different properties are observed for s and p polarizations, following the characteristics of the strong anisotropy of hyperbolic metamaterials.

  18. A noise-optimized virtual monochromatic reconstruction algorithm improves stent visualization and diagnostic accuracy for detection of in-stent re-stenosis in lower extremity run-off CT angiography.

    Science.gov (United States)

    Mangold, Stefanie; De Cecco, Carlo N; Schoepf, U Joseph; Yamada, Ricardo T; Varga-Szemes, Akos; Stubenrauch, Andrew C; Caruso, Damiano; Fuller, Stephen R; Vogl, Thomas J; Nikolaou, Konstantin; Todoran, Thomas M; Wichmann, Julian L

    2016-12-01

    To evaluate the impact of noise-optimized virtual monochromatic imaging (VMI+) on stent visualization and accuracy for in-stent re-stenosis at lower extremity dual-energy CT angiography (DE-CTA). We evaluated third-generation dual-source DE-CTA studies in 31 patients with prior stent placement. Images were reconstructed with linear blending (F_0.5) and VMI+ at 40-150 keV. In-stent luminal diameter was measured and contrast-to-noise ratio (CNR) calculated. Diagnostic confidence was determined using a five-point scale. In 21 patients with invasive catheter angiography, accuracy for significant re-stenosis (≥50 %) was assessed at F_0.5 and 80 keV-VMI+ chosen as the optimal energy level based on image-quality analysis. At CTA, 45 stents were present. DSA was available for 28 stents whereas 12 stents showed significant re-stenosis. CNR was significantly higher with ≤80 keV-VMI+ (17.9 ± 6.4-33.7 ± 12.3) compared to F_0.5 (16.9 ± 4.8; all p VMI+ (4.90 ± 0.48-4.88 ± 0.63 vs. 4.60 ± 0.66, p = 0.001, 0.0042). Sensitivity, negative predictive value and accuracy for re-stenosis were higher with 80 keV-VMI+ (100, 100, 96.4 %) than F_0.5 (90.9, 94.1, 89.3 %). 80 keV-VMI+ improves image quality, diagnostic confidence and accuracy for stent evaluation at lower extremity DE-CTA. • The impact of noise-optimized virtual monochromatic imaging on stent visualization was assessed. • Virtual monochromatic imaging significantly improves stent lumen visualization and diagnostic confidence. • At 80 keV diagnostic performance for detection of in-stent restenosis was increased. • 80 keV virtual monochromatic images are recommended for stent evaluation of lower extremity vasculature.

  19. Trace element composition and cathodoluminescence of kyanite and its petrogenetic implications

    Science.gov (United States)

    Müller, Axel; van den Kerkhof, Alfons M.; Selbekk, Rune S.; Broekmans, Maarten A. T. M.

    2016-09-01

    Kyanite crystals from fourteen localities worldwide were analysed for their abundances of the trace elements Na, Mg, K, Ca, Ti, V, Cr, Mn, and Fe and cathodoluminescence (CL) properties. Based on protolith type, metamorphic setting, and distinctive trace element fingerprints, a genetic classification of kyanite-bearing rocks is suggested: (A) Al-rich metasediments which commonly contain coarse-grained quartz-kyanite segregations; (B) metamorphosed granitic rocks, specifically granulites; (C) metamorphosed argillic alteration zones hosted originally in felsic igneous rocks; (D) metamorphosed argillic alteration zones hosted originally in mafic igneous rocks; and (E) metamorphosed mafic to ultramafic rocks, specifically eclogites. Vanadium and Cr concentrations reflect both protolith and host rock compositions and therefore may provide a geochemical fingerprint for the nature of the protolith. The incorporation of Fe into kyanite is largely controlled by oxygen fugacity during kyanite formation, and therefore, in most cases, its concentration cannot be related to that of the protolith. From our results, Ti concentration appears to be related to metamorphic grade, particularly formation temperature. If proven by further studies, Ti-in-kyanite may provide a useful geothermometer. Correlation of trace element abundances with CL spectra confirms that common red CL, which is composed of the spectral bands centred at 1.69 eV (734 nm), 1.75 eV (708 nm), and 1.80 eV (689 nm), is related to Cr3+ defects. CL spectra of most kyanites show in addition a low-intensity blue emission centred at 2.56 eV (485 nm). Correlation of the intensity of the blue emission with Ti suggests that it is related to or sensitized by Ti4+ or Ti3+ defects. Kyanites with >3200 µgg-1 Fe show generally no detectable CL due to the CL-quenching effect of Fe2+. Our findings provide new criteria in the exploration for and quality assessment of new kyanite deposits. The Ti content, one of the critical

  20. Comparison of thermoluminescence (TL) and cathodoluminescence (ESEM-CL) properties between hydrothermal and metamorphic quartzes

    Energy Technology Data Exchange (ETDEWEB)

    Topaksu, M., E-mail: mtopaksu@adiyaman.edu.tr [Department of Physics, Faculty of Science and Art, Adiyaman University, 02040 Adiyaman (Turkey); Correcher, V. [CIEMAT, Av. Complutense 22, Madrid 28040 (Spain); Garcia-Guinea, J. [CSIC, Museo Nacional de Ciencias Naturales, C/Jose Gutierrez Abascal 2, Madrid 28006 (Spain); Topak, Y. [Adiyaman University, Vocational High School, 02040 Adiyaman (Turkey); Goeksu, H.Y. [Department of Physics, Faculty of Science and Art, Adiyaman University, 02040 Adiyaman (Turkey)

    2012-06-15

    This paper reports on the Thermoluminescence (TL) and Cathodoluminescence (CL) emission of well-characterized hydrothermal milky quartz specimens from Hakkari in Turkey, labeled THQ, and Madrid in Spain, labeled SHQ, and metamorphic quartz from Madrid, in Spain, labeled SMQ. Both hydrothermal and metamorphic quartz samples display similar UV-IR CL spectra consisting of five groups of components centered at 330 nm and 380 nm linked to [AlO{sub 4}] Degree-Sign centers, 420 nm due to intrinsic defects such as oxygen vacancies, lattice defects, and impurities which modify the crystal structure, 480 nm associated with [AlO{sub 4}] Degree-Sign centers of substitutional Al{sup 3+}, and a red broad band related to the hydroxyl defects in the quartz lattice as precursors of non-bridging oxygen hole centers (NBOHC) and substitutional point defects. The Turkish quartz specimen exhibits higher CL intensity in the UV region (up to 330 nm) than the Spanish specimens probably linked to the presence of Ca (0.95% in THQ and less than 0.1% in SHQ and SMQ). At wavelengths greater than 330 nm, SMQ (formed at high pressure 6000 bars and temperatures over 500-600 Degree-Sign C) shows higher intensity than the hydrothermal (growth at 2000 bars and temperatures 200-300 Degree-Sign C) samples associated with the formation process. The natural blue TL glow curves of both THQ and SHQ display a weaker TL intensity than the SMQ, attributable to the Al (0.32%), Ti (0.14%), K (0.01%) and Zr (76 ppm) content. It is shown that mineralogical formation, crystallinity index and the content of the impurities seem to be the main parameters of influence in the shape intensity of the CL and TL glow curve emission. - Highlights: Black-Right-Pointing-Pointer We reported on the TL and CL emission of well-characterized hydrothermal milky and metamorphic quartz specimens. Black-Right-Pointing-Pointer Hydrothermal and metamorphic quartz samples displayed similar UV-IR CL spectra. Black

  1. Fluid inclusion and cathodoluminescence studies on fluorite from the Kerio valley, Kenya

    Science.gov (United States)

    Ogola, J. S.; Behr, H. J.; van den Kerkhof, A. M.

    1994-04-01

    The Kerio valley lies between the Elgeyo escarpment and the Tugen hills which mark the western margin of the Kenya rift valley. The main fluorite deposits are located in the southern part of the valley at Kimwarer, Choff and Kamnaon. Three types of inclusion fillings were identified: Liquid+Vapour, Liquid+Daughter Minerals and Liquid. The L+V type is dominant. Inclusions occur as clusters, trails along the crystal growth zones and as isolated ones. Low salinities, apparently lower than the 5% wt. NaCl equivalent, were established. Homogenization temperatures suggest that fluorite mineralization took place at different stages and at temperatures between 120 and 180 °C. Isolated readings above 180°C may be referring to the original inclusions in limestone. These measurements and the absence of CO 2 in the inclusions, as well as the occurrence of vugs and crustifications with fluorite, suggest that mineralization took place at relatively shallow depths. Emission spectrum lines representing Eu 2+, Dy 3+, Tb 3+ and Sm 3+ in fluorite were identified. Sm 3+ was detected only in the pinkish luminescence of veined fluorite, whereas the pinkish zone in banded fluorite contains Tb 3+. Eu 2+ which gives the strongest emission lines in the blue part of the visible spectrum, apparently is responsible for the strong blue cathodoluminescence (CL) in fluorite. The dominance of Eu 2+ peaks further points to the fact that fluorite mineralization in the Kerio valley took place in an environment that was enriched in Lanthanide Rare Earth Elements (LREE). The presence of rare earths and radioactive elements in fluorite points towards their enrichment in the environment of fluorite mineralization. A juvenile origin of mineral forming solutions is proposed. Two generations of fluorite were established: allotriomorphic fluorite, forming the matrix, and the idiomorphic variety, occurring either in barite or in druzes in early fluorite. Barite in turn forms idiomorphic crystals in

  2. Defects in a mixed-habit Yakutian diamond: Studies by optical and cathodoluminescence microscopy, infrared absorption, Raman scattering and photoluminescence spectroscopy

    Science.gov (United States)

    Lang, A. R.; Bulanova, G. P.; Fisher, D.; Furkert, S.; Sarua, A.

    2007-12-01

    Widespread occurrences in the crystallisation history of natural diamonds are epochs of mixed-habit growth in which normal {1 1 1}-faceted growth is accompanied by non-faceted growth on curved surfaces of mean orientation ˜{1 0 0}, termed 'cuboid'. This paper analyses mixed-habit-related phenomena in a near-central, (1 1 0)-polished slice of an octahedron from the Mir pipe, previously studied principally by SIMS probes analysing N impurity content and C and N isotope composition. In the present work, newly studied features include dislocation content, fine structure in cathodoluminescence (CL) patterns, refined IR absorption data, Raman and photoluminescence (PL) microspectroscopy and microscopy of internal non-diamond bodies. Topographic imaging and spectroscopic techniques traced the specimen's morphological evolution from a cubo-octahedral core containing complex relative development of {1 1 1} and cuboid sectors, both populated by graphite crystallites, diameters up to ˜5 μm, lying on all diamond host {1 1 1}. Coherently overgrowing the core was a zone of widely but smoothly varying relative development of {1 1 1} and cuboid sectors, both on birefringence evidence dislocation-free, emitting strongly from cuboid sectors the PL spectra associated with Ni-N-vacancy complexes. An enclosing octahedral shell of solely {1 1 1} lamellae terminated mixed-habit growth. High-resolution FTIR absorption measurements of I( B'), the integrated absorption due to {1 0 0}-platelet defects, showed from its absence or weakness that total or substantial platelet degradation had taken place in the mixed-habit zones, indicating that these had undergone conditions close to the diamond-graphite phase boundary in their history.

  3. Constraining the monochromatic gamma-rays from dark matter annihilation by the LHC

    Science.gov (United States)

    Esmaili, Arman; Khatibi, Sara; Mohammadi Najafabadi, Mojtaba

    2017-07-01

    The installation of forward detectors in CMS and ATLAS turn the LHC into an effective photon-photon collider. The elastic scattering of the beam protons via the emission of photons, which can be identified by tagging the intact protons in the forward detectors, provides a powerful diagnostic of the central production of new particles through photon-photon annihilation. In this paper we study the central production of dark matter particles and the potential of the LHC to constrain the cross section of this process. By virtue of the crossing symmetry, this limit can immediately be used to constrain the production of monochromatic gamma rays in dark matter annihilation, a smoking gun signal under investigation in indirect dark matter searches. We show that with the integrated luminosity L =30 fb-1 in the LHC at center-of-mass energy √{s }=13 TeV , for dark matter masses ˜(50 - 600 ) GeV , a model-independent constraint on the cross section of dark matter annihilation to monochromatic gamma rays at the same order of magnitude as the current Fermi-LAT and the future limits from CTA can be obtained.

  4. Control of cell interaction using quasi-monochromatic light with varying spatiotemporal coherence

    Science.gov (United States)

    Budagovsky, A. V.; Maslova, M. V.; Budagovskaya, O. N.; Budagovsky, I. A.

    2017-02-01

    By the example of plants, fungi and bacteria, we consider the possibility of controlling the interaction of cells, being in competitive, antagonistic, or parasitic relations. For this aim we used short-time irradiation (a few seconds or minutes) with the red (633 nm) quasi-monochromatic light having different spatiotemporal coherence. It is shown that the functional activity is mostly increased in the cells whose size does not exceed the coherence length and the correlation radius of the light field. Thus, in the case of cells essentially differing in size, it is possible to increase the activity of smaller cells, avoiding the stimulation of larger ones. For example, the radiation having relatively low coherence (Lcoh, rcor plant cells by pathogen fungi, while the exposure to light with less statistical regularity (Lcoh = 4 μm, rcor = 5 μm) inhibits the growth of the Fusarium microcera fungus, infected by the bacterium of the Pseudomonas species. The quasi-monochromatic radiation with sufficiently high spatiotemporal coherence stimulated all interacting species (bacteria, fungi, plants). In the considered biocenosis, the equilibrium was shifted towards the favour of organisms having the highest rate of cell division or the ones better using their adaptation potential.

  5. Rod and Rod-driven Function in Achromatopsia and Blue Cone Monochromatism

    Science.gov (United States)

    Moskowitz, Anne; Hansen, Ronald M.; Akula, James D.; Eklund, Susan E.; Fulton, Anne B.

    2008-01-01

    Purpose To evaluate rod photoreceptor and postreceptor retinal function in pediatric patients with achromatopsia (ACHR) and blue cone monochromatism (BCM) using contemporary electroretinographic (ERG) procedures. Methods Fifteen patients (age 1 to 20 years) with ACHR and six patients (age 4 to 22 years) with BCM were studied. ERG responses to full-field stimuli were obtained in scotopic and photopic conditions. Rod photoreceptor (Srod, Rrod) and rod-driven postreceptor (log σ, Vmax) response parameters were calculated from the a-wave and b-wave. The ERG records were digitally filtered to demonstrate the oscillatory potentials (OPs); a sensitivity parameter, log SOPA1/2, and an amplitude parameter, SOPAmax, were used to characterize the OP response. Response parameters were compared to those of 12 normal control subjects. Results As expected, photopic responses were non-detectable in patients with ACHR and BCM. In addition, mean scotopic photoreceptor (Rrod) and postreceptor (Vmax and SOPAmax) amplitude parameters were significantly reduced compared to those in normal controls. The flash intensity required to evoke a half maximum b-wave amplitude (log σ) was significantly increased. Conclusions The results of this study provide evidence that deficits in rod and rod mediated function occur in the primary cone dysfunction syndromes, achromatopsia and blue cone monochromatism. PMID:18824728

  6. Monochromatic light-emitting diode (LED source in layers hens during the second production cycle

    Directory of Open Access Journals (Sweden)

    Rodrigo Borille

    2015-09-01

    Full Text Available ABSTRACTLight is an important environmental factor for birds, allowing not only their vision, but also influencing their physiological responses, such as behavioral and reproductive activity. The objective of this experiment was to evaluate the impact of different colors of monochromatic light (LED sources in laying hens production during the second laying cycle. The study was conducted in an experimental laying house during 70 days. A total of 300 laying hens Isa Brown® genetic strain, aged 95 weeks, in the second laying cycle were used in the study. The artificial light sources used were blue, yellow, green, red and white. The light regimen was continuous illumination of 17 h per day (12 h natural and 5 h artificial in a daily light regimen of 17L:5D (light: dark. The Latin Square design was adopted with five treatments (five colors divided into five periods, and five boxes, with six replicates of ten birds in each box. The production and egg quality were evaluated. The different colors of light source did not affect production parameters or egg quality (p > 0.05. The monochromatic light source may be considered as an alternative to artificial lighting in laying hens during the second production cycle.

  7. Constraining the monochromatic gamma-rays from dark matter annihilation by the LHC

    CERN Document Server

    Esmaili, Arman; Najafabadi, Mojtaba Mohammadi

    2016-01-01

    The installation of forward detectors in CMS and ATLAS turn the LHC to an effective photon-photon collider. The elastic scattering of the beam-protons via the emission of photons, which can be identified by tagging the intact protons in the forward detectors, provides a powerful diagnostic of the central production of new particles through photon-photon annihilation. In this letter we study the central production of dark matter particles and the potential of LHC to constrain the cross section of this process. By virtue of the crossing symmetry, this limit can immediately be used to constrain the production of monochromatic gamma-rays in dark matter annihilation, a smoking gun signal under investigation in indirect dark matter searches. We show that with the integrated luminosity $\\mathcal{L}=30~{\\rm fb}^{-1}$ in LHC at center-of-mass energy $\\sqrt{s}=$ 13 TeV, for dark matter masses $\\sim (50-600)$ GeV, a model-independent constraint on the cross section of dark matter annihilation to monochromatic gamma-rays...

  8. Effects of monochromatic light on quality properties and antioxidation of meat in broilers.

    Science.gov (United States)

    Ke, Y Y; Liu, W J; Wang, Z X; Chen, Y X

    2011-11-01

    Our previous study demonstrated that blue monochromatic light was better to promote the growth and development of broilers than red light. However, consumer research suggests that the eating quality of the meat is more important. The present study was, therefore, designed to further evaluate the effects of various monochromatic lights on the muscle growth and quality properties and antioxidation of meat. A total of 288 newly hatched Arbor Acre male broilers were exposed to blue light (BL), green light (GL), red light (RL), and white light (WL) by a light-emitting diode system for 49 d, respectively. Results showed that the broilers reared under BL significantly increased BW and carcass yield as compared with RL, WL, and GL (P 0.05). Compared with RL, the muscles of breast and thigh in GL and BL had higher pH, water-holding capacity, and protein content, whereas cooking loss, lightness value, shear value, and fat content were lower (P 0.05). These results suggest that BL better improves meat quality of Arbor Acre broilers by elevating antioxidative capacity than does RL.

  9. Skin Treatment with Pulsed Monochromatic UVA1 355 Device and Computerized Morphometric Analysis of Histochemically Identified Langerhans Cells

    Directory of Open Access Journals (Sweden)

    Nicola Zerbinati

    2016-01-01

    Full Text Available Fluorescent or metal halide lamps are widely used in therapeutic applications in dermatological diseases, with broadband or narrow band emission UVA/UVA1 (320–400 nm obtained with suitable passive filters. Recently, it has been possible for us to use a new machine provided with solid state source emitting pulsed monochromatic UVA1 355 nm. In order to evaluate the effects of this emission on immunocells of the skin, human skin samples were irradiated with monochromatic 355 nm UVA1 with different energetic fluences and after irradiation Langerhans cells were labeled with CD1a antibodies. The immunohistochemical identification of these cells permitted evaluating their modifications in terms of density into the skin. Obtained results are promising for therapeutical applications, also considering that a monochromatic radiation minimizes thermic load and DNA damage in the skin tissues.

  10. Co-doping of Ag into Mn:ZnSe Quantum Dots: Giving Optical Filtering effect with Improved Monochromaticity

    OpenAIRE

    Zhiyang Hu; Shuhong Xu; Xiaojing Xu; Zhaochong Wang; Zhuyuan Wang; Chunlei Wang; Yiping Cui

    2015-01-01

    In optics, when polychromatic light is filtered by an optical filter, the monochromaticity of the light can be improved. In this work, we reported that Ag dopant atoms could be used as an optical filter for nanosized Mn:ZnSe quantum dots (QDs). If no Ag doping, aqueous Mn:ZnSe QDs have low monochromaticity due to coexisting of strong ZnSe band gap emission, ZnSe trap emission, and Mn dopant emission. After doping of Ag into QDs, ZnSe band gap and ZnSe trap emissions can be filtered, leaving o...

  11. Detection limits for actinides in a monochromatic, wavelength-dispersive x-ray fluorescence instrument

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Michael L [Los Alamos National Laboratory; Havrilla, George J [Los Alamos National Laboratory

    2009-01-01

    Recent developments in x-ray optics have made it possible to examine the L x-rays of actinides using doubly-curved crystals in a bench-top device. A doubly-curved crystal (DCC) acts as a focusing monochromatic filter for polychromatic x-rays. A Monochromatic, Wavelength-Dispersive X-Ray Fluorescence (MWDXRF) instrument that uses DCCs to measure Cm and Pu in reprocessing plant liquors was proposed in 2007 by the authors at Los Alamos National Laboratory. A prototype design of this MWDXRF instrument was developed in collaboration with X-ray Optical Systems Inc. (XOS), of East Greenbush, New York. In the MWDXRF instrument, x-rays from a Rhodium-anode x-ray tube are passed through a primary DCC to produce a monochromatic beam of 20.2-keV photons. This beam is focused on a specimen that may contain actinides. The 20.2-keV interrogating beam is just above the L3 edge of Californium; each actinide (with Z = 90 to 98) present in the specimen emits characteristic L x-rays as the result of L3-shell vacancies. In the LANL-XOS prototype MWDXRf, these x-rays enter a secondary DCC optic that preferentially passes 14.961-keV photons, corresponding to the L-alpha-1 x-ray peak of Curium. In the present stage of experimentation, Curium-bearing specimens have not been analyzed with the prototype MWDXRF instrument. Surrogate materials for Curium include Rubidium, which has a K-beta-l x-ray at 14.961 keV, and Yttrium, which has a K-alpha-1 x-ray at 14.958 keV. In this paper, the lower limit of detection for Curium in the LANL-XOS prototype MWDXRF instrument is estimated. The basis for this estimate is described, including a description of computational models and benchmarking techniques used. Detection limits for other actinides are considered, as well as future safeguards applications for MWDXRF instrumentation.

  12. UHP-Metamorphic Pyrope Quartzites From Dora Maira: Cathodoluminescence of Silica and Twinning of Coesite

    Science.gov (United States)

    Schertl, H.; Medenbach, O.; Neuser, R. D.

    2005-12-01

    Since the first discovery of metamorphic coesite in ultrahigh-pressure (UHP) rocks from the Dora Maira Massif/Western Alps, much attention was drawn on its characteristics: the paragenesis, influence of OH on the kinetics of the coesite-quartz transition, present day overpressure in coesite inclusions, features like palisade-quartz as typical breakdown product, experimental studies on the rheology of polycrystalline coesite, oxygen isotope signatures, etc. Here we would like to focus on the cathodoluminescence (CL) of coesite and its breakdown products. Since luminescence is triggered even by minor differences in composition or structure of a mineral, in this study the CL microscope is employed not only as a powerful tool to distinguish between different mineral phases but also to characterize different generations of a coesite breakdown product. A second topic concerns the twinning of coesite which is very rarely observed in nature. The investigations were made on pyrope quartzite previously representing a pyrope coesitite at UHP metamorphic conditions (Chopin, 1984; Schertl et al., 1991). Main constituent phases are pyrope, quartz, phengite, talc, and kyanite with minor amounts of coesite and jadeite. The rock can be subdivided in a fine-grained type containing pyropes up to about 1.5 cm and a coarse-grained type with pyrope crystals up to 25 cm. The boundaries between both types are irregular, but they exhibit significant differences concerning their mineral inclusions: inclusions of coesite/quartz (in paragenesis with kyanite and phengite) are only observed in small pyropes whereas in big pyropes no silica phase occurs. Typical mineral inclusions in big pyropes essentially are kyanite, talc, and chlorite with minor amounts of ellenbergerite, Mg-dumortierite and sodic amphibole. Coesite typically shows bluish-green luminescence colours, whereas palisade-like quartz as breakdown product (interpreted to be formed at high temperatures) surrounding coesite is

  13. Surface Characterisation and Cathodoluminescent Response of Nanodot-Patterned GaSb Surfaces by Low Energy Ion Sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Plaza, J L [Laboratorio de Crecimiento de Cristales, Departamento de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, 28049, Cantoblanco, Madrid (Spain); Hidalgo, P [Departamento de Fisica de Materiales, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, 28045, Madrid (Spain); Dieguez, E [Laboratorio de Crecimiento de Cristales, Departamento de Fisica de Materiales, Facultad de Ciencias, Universidad Autonoma de Madrid, 28049, Cantoblanco, Madrid (Spain)

    2007-04-15

    The scope of this paper is to analyse the effect of Au and Cr impurities, diffused onto GaSb substrates on the formation of nanodots created by LEIS using Ar+ ions It is concluded that oblique incidence in rotating configuration delays the formation of the nanodots compared to previously reported normal incidence experiments. The presence of cracks induced by the sputtering process has been observed both in the Au and Cr diffused samples. Cathodoluminescence (CL) spectra obtained in irradiated samples both pure and Crdiffused have revealed no difference between them, showing the usual three band encountered in this material (Band Gap at 798 meV, A Band at 777 meV and tail-states at 815 meV). However, a fourth band has been detected in the Au sample centered at 769 meV.

  14. Cathodoluminescence and electroluminescence from multi-layered organic structures induced by field electron emission from carbon nanotubes

    Science.gov (United States)

    Kuznetzov, Alexander A.; Zakhidov, Alexander A.; Ovalle, Raquel; Nanjundaswami, Rashmi; Williams, Christopher; Zhang, Mei; Lee, Sergey B.; Ferraris, John; Zakhidov, Anvar A.

    2005-10-01

    We report the observation of cathodoluminescence (CL) of organic multilayers of tris-(8-hydroxyquinoline) aluminium (Alq3) and 2- (4biphenyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole (PBD) deposited on ITO-coated glass, with and without hole transport layer and compare it with electroluminescence (EL) from similar devices. Excitation of the CL of such multilayer organic anodes was accomplished by low energy electrons field emitted by single walled carbon nanotube cathodes. The dependence of CL spectrum and intensity on voltage (V), current (I), type of transport layer and the cathode-anode geometry has been studied. We propose carbon nanotubes as efficient cathodes for stable CL emission from multi-layer anodes at small cathode-anode separations. The role of hole-transport layer is also discussed.

  15. Computational study of nonlinear plasma waves: 1: Simulation model and monochromatic wave propagation

    Science.gov (United States)

    Matda, Y.; Crawford, F. W.

    1974-01-01

    An economical low noise plasma simulation model is applied to a series of problems associated with electrostatic wave propagation in a one-dimensional, collisionless, Maxwellian plasma, in the absence of magnetic field. The model is described and tested, first in the absence of an applied signal, and then with a small amplitude perturbation, to establish the low noise features and to verify the theoretical linear dispersion relation at wave energy levels as low as 0.000,001 of the plasma thermal energy. The method is then used to study propagation of an essentially monochromatic plane wave. Results on amplitude oscillation and nonlinear frequency shift are compared with available theories. The additional phenomena of sideband instability and satellite growth, stimulated by large amplitude wave propagation and the resulting particle trapping, are described.

  16. Energy dependence of CP-violation reach for monochromatic neutrino beam

    Energy Technology Data Exchange (ETDEWEB)

    Bernabeu, Jose [IFIC, Universitat de Valencia-CSIC, E-46100, Burjassot, Valencia (Spain); Espinoza, Catalina [IFIC, Universitat de Valencia-CSIC, E-46100, Burjassot, Valencia (Spain)], E-mail: m.catalina.espinoza@uv.es

    2008-06-26

    The ultimate goal of future neutrino facilities is the determination of CP violation in neutrino oscillations. Besides |U(e3)|{ne}0, this will require precision experiments with a very intense neutrino source and energy control. With this objective in mind, the creation of monochromatic neutrino beams from the electron capture decay of boosted ions by the SPS of CERN has been proposed. We discuss the capabilities of such a facility as a function of the energy of the boost and the baseline for the detector. We compare the physics potential for two different configurations: (I) {gamma}=90 and {gamma}=195 (maximum achievable at present SPS) to Frejus; (II) {gamma}=195 and {gamma}=440 (maximum achievable at upgraded SPS) to Canfranc. We conclude that the SPS upgrade to 1000 GeV is important to reach a better sensitivity to CP violation iff it is accompanied by a longer baseline.

  17. A Photodegradation Study of Three Common Paint and Plaster Biocides under monochromatic UV Light

    DEFF Research Database (Denmark)

    Minelgaite, Greta; Vollertsen, Jes; Nielsen, Asbjørn Haaning

    2014-01-01

    Photodegradation of the three common paint-and-plaster biocides (carbendazim, diuron and terbutryn) was investigated at controlled laboratory conditions. Samples prepared in two types of water (demineralized water and pond water) were subjected to 254 nm monochromatic UV light. Light intensity (W m......-2) in the experimental chamber was measured by a fiber optic spectrometer. The observed decline in biocide concentration was related with the light energy, accumulated during the time of degradation (kJ m-2), and 1st order photodegradation rate constants (m2 kJ-1) were determined. The obtained...... results demonstrated that diuron and terbutryn were readily degradable at the tested conditions, while carbendazim remained stable throughout the 28 – 34 hours of the experiments. Photodegradation rate constants of diuron and terbutryn were found to be slightly higher in demineralized water (0.0183 – 0...

  18. Monochromatic radiography of high energy density physics experiments on the MAGPIE generator.

    Science.gov (United States)

    Hall, G N; Burdiak, G C; Suttle, L; Stuart, N H; Swadling, G F; Lebedev, S V; Smith, R A; Patankar, S; Suzuki-Vidal, F; de Grouchy, P; Harvey-Thompson, A J; Bennett, M; Bland, S N; Pickworth, L; Skidmore, J

    2014-11-01

    A monochromatic X-ray backlighter based on Bragg reflection from a spherically bent quartz crystal has been developed for the MAGPIE pulsed power generator at Imperial College (1.4 MA, 240 ns) [I. H. Mitchell et al., Rev. Sci. Instrum. 67, 1533 (2005)]. This instrument has been used to diagnose high energy density physics experiments with 1.865 keV radiation (Silicon He-α) from a laser plasma source driven by a ∼7 J, 1 ns pulse from the Cerberus laser. The design of the diagnostic, its characterisation and performance, and initial results in which the instrument was used to radiograph a shock physics experiment on MAGPIE are discussed.

  19. A compact design for monochromatic OSL measurements in the wavelength range 380-1020 nm

    Energy Technology Data Exchange (ETDEWEB)

    Boetter-Jensen, L.; Poolton, N.R.J.; Willumsen, F.; Christiansen, H. [Risoe National Lab., Roskilde (Denmark)

    1994-04-01

    The development and performance of a compact module is described that allows for the monochromatic illumination of samples in the wavelength range 380-1020 nm, enabling the measurement of energy-resolved optically stimulated luminescence. The unit is designed to couple directly to the existing automated Risoe TL/OSL dating apparatus, thus allowing for either routine scanning or more detailed thermo-optical investigations. The high throughput efficiency of the unit means that the existing 75 W tungsten-halogen lamp can be directly used for such measurements on both quartz and feldspar samples. The design allows for rapid spectral scanning with a choice of resolution of anywhere between 10 and 80 nm: stray light levels are less than 0.01%. The unit can equally be used for recording wavelength-resolved emission spectra, whether photo-excited or thermally stimulated; the capabilities of the system are demonstrated in the article. (author).

  20. Monochromatic radiography of high energy density physics experiments on the MAGPIE generator

    Energy Technology Data Exchange (ETDEWEB)

    Hall, G. N., E-mail: gareth.hall@imperial.ac.uk; Burdiak, G. C.; Suttle, L.; Stuart, N. H.; Swadling, G. F.; Lebedev, S. V.; Smith, R. A.; Patankar, S.; Suzuki-Vidal, F.; Grouchy, P. de; Harvey-Thompson, A. J.; Bennett, M.; Bland, S. N.; Pickworth, L.; Skidmore, J. [The Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom)

    2014-11-15

    A monochromatic X-ray backlighter based on Bragg reflection from a spherically bent quartz crystal has been developed for the MAGPIE pulsed power generator at Imperial College (1.4 MA, 240 ns) [I. H. Mitchell et al., Rev. Sci. Instrum. 67, 1533 (2005)]. This instrument has been used to diagnose high energy density physics experiments with 1.865 keV radiation (Silicon He-α) from a laser plasma source driven by a ∼7 J, 1 ns pulse from the Cerberus laser. The design of the diagnostic, its characterisation and performance, and initial results in which the instrument was used to radiograph a shock physics experiment on MAGPIE are discussed.

  1. Parametric decay of a parallel propagating monochromatic whistler wave: Particle-in-cell simulations

    Science.gov (United States)

    Ke, Yangguang; Gao, Xinliang; Lu, Quanming; Wang, Shui

    2017-01-01

    In this paper, by using one-dimensional (1-D) particle-in-cell simulations, we investigate the parametric decay of a parallel propagating monochromatic whistler wave with various wave frequencies and amplitudes. The pump whistler wave can decay into a backscattered daughter whistler wave and an ion acoustic wave, and the decay instability grows more rapidly with the increase of the frequency or amplitude. When the frequency or amplitude is sufficiently large, a multiple decay process may occur, where the daughter whistler wave undergoes a secondary decay into an ion acoustic wave and a forward propagating whistler wave. We also find that during the parametric decay a considerable part of protons can be accelerated along the background magnetic field by the enhanced ion acoustic wave through the Landau resonance. The implication of the parametric decay to the evolution of whistler waves in Earth's magnetosphere is also discussed in the paper.

  2. Statistical analysis of monochromatic whistler waves near the Moon detected by Kaguya

    Directory of Open Access Journals (Sweden)

    Y. Katoh

    2011-05-01

    Full Text Available Observations are presented of monochromatic whistler waves near the Moon detected by the Lunar Magnetometer (LMAG on board Kaguya. The waves were observed as narrowband magnetic fluctuations with frequencies close to 1 Hz, and were mostly left-hand polarized in the spacecraft frame. We performed a statistical analysis of the waves to identify the distributions of their intensity and occurrence. The results indicate that the waves were generated by the solar wind interaction with lunar crustal magnetic anomalies. The conditions for observation of the waves strongly depend on the solar zenith angle (SZA, and a high occurrence rate is recognized in the region of SZA between 40° to 90° with remarkable north-south and dawn-dusk asymmetries. We suggest that ion beams reflected by the lunar magnetic anomalies are a possible source of the waves.

  3. Non-destructive characterization of minerals in ancient Greek ceramics using monochromatic neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Siouris, I M [Department of Production and Management Engineering, Democritus University of Thrace Xanthi, 67100 Xanthis (Greece); Department of Informatics and Communication, Technological and Educational, Institute of Serres, SimLab, 62124 Serres (Greece)], E-mail: jsiou@pme.duth.gr

    2008-03-12

    A collection of ancient Greek ceramic pieces originating from different excavations from Neos Scopos, Serres, in the North East of Greece has been studied at room temperature by means of non-destructive neutron diffraction using a monochromatic beam. Quantitative phase analyses revealed different compositions of the mineral fractions present, but a general similarity of the main materials is still recognizable. It is shown that the observed variations are partly due to the experimental set-up and they can be remedied by taking a sufficient number of measurements for different sample orientations while bathing the entire object in the beam. An additional reason for the observed anomaly in the mineral phase compositions may be the different heat treatments to which the mixtures of clays/pastes was subjected as well as the postproduction environmental conditions for the selected samples. The firing temperatures were estimated to be in the range of 850-1000 deg. C.

  4. Electron Spin Resonance of Single Crystals of Cystine Dihydrochloride Irradiated with Monochromatic UV Radiation at Various Wavelenghts

    DEFF Research Database (Denmark)

    Lund-Thomsen, E.; Nielsen, S. O.

    1972-01-01

    Single crystals of cystine dihydrochloride were irradiated at room temperature with monochromatic uv radiation. The optical bandwidth was about 20 Å for each wavelength used. Essentially two ESR centers were observed, the relative yield being approximately 1. One center is identified as the RS...

  5. SEM-Cathodoluminescence and fluid inclusion study of quartz veins in Hugo Dummett porphyry Cu-Au deposit,South Mongolia

    Science.gov (United States)

    Sanjaa, M.; Fujimaki, H.; Ken-Ichiro, H.

    2010-12-01

    The Hugo Dummett porphyry copper-gold deposit in Oyu Tolgoi, South Mongolia is a high-sulfidation type deposit which consists of Cu-Au bearing quartz veins. Cathodoluminescence (CL) analysis using scanning electron microscope (SEM) and fluid inclusion microthermometer were performed to elucidate the relationship between CL structures, fluid inclusion microthermometer of different quartz generations, and ore forming process of the Hugo Dummett deposit. Hydrothermal quartz from quartz-sulfide veins in the porphyry Cu-Au deposit in Hugo Dummett, revealing the following textures: (1) euhedral growth zones (2) embayed and rounded CL-bright cores, with CL-dark and CL-gray overgrowths, (3) concentric and non concentric growth zones, and (4) CL dark/bright microfractures. These textures indicate that many veins have undergone fracturing, growth of quartz into fluid-filled space and quartz dissolution of quartz. SEM-CL imaging indicates vein quartz in the Hugo Dummett deposit, initially grew as individual CL-bright crystals 356 ± 10°C liquid-reservoir (average Th value for fluid inclusions in the crystal cores is 359°C). In contract, SEM-CL imaging shows the edges of the micron-scale growth zones of varying CL intensity, reflecting quartz precipitation at some later time, when the Hugo Dummett deposit hydrothermal system had cooled, when reservoir conditions were about 211 ± 25°C (average Th value of 212°C). Crystal growth is SEM-CL evidence of the vein quartz having been partly dissolved. Pressure change has a large effect on quartz solubility and may have been responsible for quartz dissolution and precipitation textures in the cooling hydrothermal system. CL-dark microfractures homogenization temperatures lower 169 ± 16°C (average Th value 170°C) than CL bright and CL gray. Temperature and pressure of the mineralized fluid estimates a pressure of formation of 0.3-0.5 kbar (lithostatic), was formed at approximately 2 km depth, as well as a formation temperature

  6. Effects of monochromatic light on mucosal mechanical and immunological barriers in the small intestine of broilers.

    Science.gov (United States)

    Xie, D; Li, J; Wang, Z X; Cao, J; Li, T T; Chen, J L; Chen, Y X

    2011-12-01

    Our previous studies demonstrated that green and blue monochromatic lights were effective to stimulate immune response of the spleen in broilers. This study was designed to investigate the effects of monochromatic light on both gut mucosal mechanical and immunological barriers. A total of 120 Arbor Acre male broilers on post-hatching day (P) 0 were exposed to red light, green light (GL), blue light (BL), and white light (WL) for 49 d, respectively. As compared with broilers exposed to WL, the broilers exposed to GL showed that the villus height of small intestine was increased by 19.5% (P = 0.0205) and 38.8% (P = 0.0149), the crypt depth of small intestine was decreased by 15.1% (P = 0.0049) and 10.1% (P = 0.0005), and the ratios of villus height to crypt depth were increased by 39.3% (P < 0.0001) and 52.5% (P < 0.0001) at P7 and P21, respectively. Until P49, an increased villus height (33.6%, P = 0.0076), a decreased crypt depth (15.4%, P = 0.0201), and an increased villus height-to-crypt depth ratio (58.5%, P < 0.0001) were observed in the BL group as compared with the WL group. On the other hand, the numbers of intestinal intraepithelial lymphocytes (27.9%, P < 0.0001 and 37.0%, P < 0.0001), goblet cells (GC, 22.1%, P < 0.0001 and 18.1%, P < 0.0001), and IgA(+) cells (14.8%, P = 0.0543 and 47.9%, P = 0.0377) in the small intestine were significantly increased in the GL group as compared with the WL group at P7 and P21, respectively. The numbers of intestinal intraepithelial lymphocytes (36.2%, P < 0.0001), GC (26.5%, P < 0.0001), and IgA(+) cells (68.0%, P = 0.0177) in the BL group were also higher than those in the WL group at P49. These results suggest that both mucosal mechanical and immunological barriers of the small intestine may be improved by rearing broilers under GL at an early age and under BL at an older age.

  7. Geochemistry of the Spor Mountain rhyolite, western Utah, as revealed by laser ablation ICP-MS, cathodoluminescence, and electron microprobe analysis

    Science.gov (United States)

    Dailey, S. R.; Christiansen, E. H.; Dorais, M.; Fernandez, D. P.

    2015-12-01

    The Miocene topaz rhyolite at Spor Mountain in western Utah hosts one of the largest beryllium deposits in the world and was responsible for producing 85% of the beryllium mined worldwide in 2010 (Boland, 2012). The Spor Mountain rhyolite is composed primarily of Ca-poor plagioclase (An8), sodic sanidine (Or40), Fe-rich biotite (Fe/(Fe+Mg)>0.95; Al 1.2-1.4 apfu), and Ti-poor quartz, along with several trace-element rich accessory phases including zircon, monazite, thorite, columbite, and allanite. Cathodoluminescence (CL) studies of quartz show oscillatory zoning, with 80% of the examined crystals displaying euhedral edges and slightly darker rims. CL images were used to guide laser ablation (LA) ICP-MS analysis of quartz, along with analyses of plagioclase, sanidine, biotite, and glass. Ti concentrations in quartz are 20±6 ppm; there is no quantifiable variation of Ti from core to rim within the diameter of the laser spot (53 microns). Temperatures, calculated using Ti in quartz (at 2 kb, aTiO2=0.34), vary between 529±10 C (Thomas et al., 2011), 669±13 C (Huang and Audetat, 2012), and 691±13 C (Wark and Watson, 2006). Two feldspar thermometry yield temperatures of 686±33 C (Elkins and Grove, 1990) and 670±41 C (Benisek et al., 2010). Zr saturation temperatures (Watson and Harrison, 1983) average 711±28 C. Analysis of the glass reveal the Spor Mountain rhyolite is greatly enriched in rare elements (i.e. Li, Be, F, Ga, Rb, Nb, Mo, Sn, and Ta) compared to average continental crust (Rudnick and Gao, 2003). Be in the glass can have as much as 100 ppm, nearly 50 times the concentration in continental crust. REE partition coefficients for sanidine are 2 to 3 times higher in the Spor Mountain rhyolite when compared to other silicic magmas (Nash and Crecraft, 1985; Mahood and Hildreth, 1983), although plagioclase tends to have lower partition coefficients; biotite has lower partition coefficients for LREE and higher partition coefficients for HREE. The patterns of

  8. Characterization of grown-in dislocations in high-quality glucose isomerase crystals by synchrotron monochromatic-beam X-ray topography

    Science.gov (United States)

    Suzuki, Ryo; Koizumi, Haruhiko; Kojima, Kenichi; Fukuyama, Seijiro; Arai, Yasutomo; Tsukamoto, Katsuo; Suzuki, Yoshihisa; Tachibana, Masaru

    2017-06-01

    High quality glucose isomerase (GI) single crystals are grown by using chemical cross-linked seed crystals. The crystal structure is an orthorhombic system in which the molecular arrangement is close to a body-centered cubic (bcc) one. The crystal defects, especially dislocations, in GI crystals are experimentally characterized by synchrotron monochromatic-beam X-ray topography. Two straight dislocations are clearly observed, which originate from the interface between the cross-linked seed crystal and the grown crystal. From the invisibility criterion of the dislocation images, it is experimentally identified that they are close to be of pure edge character with the Burgers vector of [1 1 bar 1] which is typical one in bcc metal crystals. Moreover, bead-like contrasts along the dislocation images and the equal-thickness fringes, related to Pendellösung fringes, at crystal edges are clearly observed, which have never been observed in other protein crystals so far. These contrasts can attributed to the dynamical diffraction effect which has been often observed in high-quality crystals such as Si. Thus it seems that the perfection of GI crystals shown in this paper is extremely high compared with other protein crystals reported so far.

  9. Far-ultraviolet astronomical narrowband imaging.

    Science.gov (United States)

    Cook, Timothy A; Hicks, Brian A; Jung, Paul G; Chakrabarti, Supriya

    2009-04-01

    We describe an all-reflective system for narrowband imaging suitable for imaging emission lines in the far ultraviolet. The system, which we call a monochromatic imager, combines a pupil plane grating monochromator with a telescope and camera to image a scene in one or more very narrow bands. The monochromator uses physical stops at its input and output apertures, and, as a result, the system has excellent rejection of out-of-band and off-axis light.

  10. Intensity of quartz cathodoluminescence and trace-element content in quartz from the porphyry copper deposit at Butte, Montana

    Science.gov (United States)

    Rusk, B.G.; Reed, M.H.; Dilles, J.H.; Kent, A.J.R.

    2006-01-01

    Textures of hydrothermal quartz revealed by cathodoluminescence using a scanning electron microscope (SEM-CL) reflect the physical and chemical environment of quartz formation. Variations in intensity of SEM-CL can be used to distinguish among quartz from superimposed mineralization events in a single vein. In this study, we present a technique to quantify the cathodoluminescent intensity of quartz within individual and among multiple samples to relate luminescence intensity to specific mineralizing events. This technique has been applied to plutonic quartz and three generations of hydrothermal veins at the porphyry copper deposit in Butte, Montana. Analyzed veins include early quartz-molybdenite veins with potassic alteration, pyrite-quartz veins with sericitic alteration, and Main Stage veins with intense sericitic alteration. CL intensity of quartz is diagnostic of each mineralizing event and can be used to fingerprint quartz and its fluid inclusions, isotopes, trace elements, etc., from specific mineralizing episodes. Furthermore, CL intensity increases proportional to temperature of quartz formation, such that plutonic quartz from the Butte quartz monzonite (BQM) that crystallized at temperatures near 750 ??C luminesces with the highest intensity, whereas quartz that precipitated at ???250 ??C in Main Stage veins luminesces with the least intensity. Trace-element analyses via electron microprobe and laser ablation-ICP-MS indicate that plutonic quartz and each generation of hydrothermal quartz from Butte is dominated by characteristic trace amounts of Al, P, Ti, and Fe. Thus, in addition to CL intensity, each generation of quartz can be distinguished based on its unique trace-element content. Aluminum is generally the most abundant element in all generations of quartz, typically between 50 and 200 ppm, but low-temperature, Main Stage quartz containing 400 to 3600 ppm Al is enriched by an order of magnitude relative to all other quartz generations. Phosphorous

  11. Tunable, all-optical quasi-monochromatic Thomson X-ray source

    CERN Document Server

    Khrennikov, K; Buck, A; Xu, J; Heigoldt, M; Veisz, L; Karsch, S

    2014-01-01

    Brilliant X-ray sources are of great interest for many research fields from biology via medicine to material research. The quest for a cost-effective, brilliant source with unprecedented temporal resolution has led to the recent realization of various high-intensity-laser-driven X-ray beam sources. Here we demonstrate the first all-laser-driven, energy-tunable and quasi-monochromatic X-ray source based on Thomson backscattering. This is a decisive step beyond previous results, where the emitted radiation exhibited an uncontrolled broad energy distribution. In the experiment, one part of the laser beam was used to drive a few-fs bunch of quasi-monoenergetic electrons from a Laser-Wakefield Accelerator (LWFA), while the remainder was scattered off the bunch in a near-counter-propagating geometry. When the electron energy was tuned from 10-50 MeV, narrow-bandwidth X-ray spectra peaking at 5-35keV were directly measured, limited in photon energy by the sensitivity curve of our X-ray detector. Due to the ultrashor...

  12. The capabilities of monochromatic EC neutrino beams with the SPS upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Espinoza, C; Bernabeu, J [IFIC, Universidad de Valencia-CSIC, E-46100, Burjassot, Valencia (Spain)], E-mail: m.catalina.espinoza@uv.es, E-mail: jose.bernabeu@uv.es

    2008-05-15

    The goal for future neutrino facilities is the determination of the U(e3) mixing and CP violation in neutrino oscillations. This will require precision experiments with a very intense neutrino source and energy control. With this objective in mind, the creation of monochromatic neutrino beams from the electron capture decay of boosted ions by the SPS of CERN has been proposed. We discuss the capabilities of such a facility as a function of the energy of the boost and the baseline for the detector. We conclude that the SPS upgrade to 1000 GeV is crucial to reach a better sensitivity to CP violation iff it is accompanied by a longer baseline. We compare the physics potential for two different configurations: I) {gamma} = 90 and {gamma} = 195 (maximum achievable at present SPS) to Frejus; II) {gamma} = 195 and {gamma} = 440 (maximum achievable at upgraded SPS) to Canfranc. The main conclusion is that, whereas the gain in the determination of U(e3) is rather modest, setup II provides much better sensitivity to CP violation.

  13. Modulatory Effect of Monochromatic Blue Light on Heat Stress Response in Commercial Broilers

    Science.gov (United States)

    Abdo, Safaa E.; Mahmoud, Shawky

    2017-01-01

    In a novel approach, monochromatic blue light was used to investigate its modulatory effect on heat stress biomarkers in two commercial broiler strains (Ross 308 and Cobb 500). At 21 days old, birds were divided into four groups including one group housed in white light, a second group exposed to blue light, a 3rd group exposed to white light + heat stress, and a 4th group exposed to blue light + heat stress. Heat treatment at 33°C lasted for five h for four successive days. Exposure to blue light during heat stress reduced MDA concentration and enhanced SOD and CAT enzyme activities as well as modulated their gene expression. Blue light also reduced the degenerative changes that occurred in the liver tissue as a result of heat stress. It regulated, though variably, liver HSP70, HSP90, HSF1, and HSF3 gene expression among Ross and Cobb chickens. Moreover, the Cobb strain showed better performance than Ross manifested by a significant reduction of rectal temperature in the case of H + B. Furthermore, a significant linear relationship was found between the lowered rectal temperature and the expression of all HSP genes. Generally, the performance of both strains by most assessed parameters under heat stress is improved when using blue light. PMID:28698764

  14. Experimental and Numerical Studies on Wave Breaking Characteristics over a Fringing Reef under Monochromatic Wave Conditions

    Directory of Open Access Journals (Sweden)

    Jong-In Lee

    2014-01-01

    Full Text Available Fringing reefs play an important role in protecting the coastal area by inducing wave breaking and wave energy dissipation. However, modeling of wave transformation and energy dissipation on this topography is still difficult due to the unique structure. In the present study, two-dimensional laboratory experiments were conducted to investigate the cross-shore variations of wave transformation, setup, and breaking phenomena over an idealized fringing reef with the 1/40 reef slope and to verify the Boussinesq model under monochromatic wave conditions. One-layer and two-layer model configurations of the Boussinesq model were used to figure out the model capability. Both models predicted well (r2>0.8 the cross-shore variation of the wave heights, crests, troughs, and setups when the nonlinearity is not too high (A0/h0<0.07 in this study. However, as the wave nonlinearity and steepness increase, the one-layer model showed problems in prediction and stability due to the error on the vertical profile of fluid velocity. The results in this study revealed that one-layer model is not suitable in the highly nonlinear wave condition over a fringing reef bathymetry. This data set can contribute to the numerical model verification.

  15. Optical theorem for two-dimensional (2D) scalar monochromatic acoustical beams in cylindrical coordinates.

    Science.gov (United States)

    Mitri, F G

    2015-09-01

    The optical theorem for plane waves is recognized as one of the fundamental theorems in optical, acoustical and quantum wave scattering theory as it relates the extinction cross-section to the forward scattering complex amplitude function. Here, the optical theorem is extended and generalized in a cylindrical coordinates system for the case of 2D beams of arbitrary character as opposed to plane waves of infinite extent. The case of scalar monochromatic acoustical wavefronts is considered, and generalized analytical expressions for the extinction, absorption and scattering cross-sections are derived and extended in the framework of the scalar resonance scattering theory. The analysis reveals the presence of an interference scattering cross-section term describing the interaction between the diffracted Franz waves with the resonance elastic waves. The extended optical theorem in cylindrical coordinates is applicable to any object of arbitrary geometry in 2D located arbitrarily in the beam's path. Related investigations in optics, acoustics and quantum mechanics will benefit from this analysis in the context of wave scattering theory and other phenomena closely connected to it, such as the multiple scattering by a cloud of particles, as well as the resulting radiation force and torque.

  16. Time-reversing a monochromatic subwavelength optical focus by optical phase conjugation of multiply-scattered light

    CERN Document Server

    Park, Jongchan; Lee, KyeoReh; Cho, Yong-Hoon; Park, YongKeun

    2016-01-01

    Due to its time-reversal nature, optical phase conjugation generates a monochromatic light wave which retraces its propagation paths. Here, we demonstrate the regeneration of a subwavelength optical focus by phase conjugation. Monochromatic light from a subwavelength source is scattered by random nanoparticles, and the scattered light is phase conjugated at the far-field region by coupling its wavefront into a single-mode optical reflector using a spatial light modulator. Then the conjugated beam retraces its propagation paths and forms a refocus on the source at the subwavelength scale. This is the first direct experimental realization of subwavelength focusing beyond the diffraction limit with far-field time reversal in the optical domain.

  17. Thermoluminescence dependence on the wavelength of monochromatic UV-radiation in Cu-doped KCl and KBr at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Perez R, A.; Piters, T.; Aceves, R.; Rodriguez M, R.; Perez S, R., E-mail: rperez@cifus.uson.mx [Universidad de Sonora, Departamento de Investigaciones en Fisica, Apdo. Postal 5-088, 83190 Hermosillo, Sonora (Mexico)

    2014-08-15

    Thermoluminescence (Tl) dependence on the UV irradiation wavelengths from 200 to 500 nm in Cu-doped KCl and KBr crystals with different thermal treatment has been analyzed. Spectrum of the Tl intensity of each material show lower intensity at wavelengths longer than 420 nm. The Tl intensity depends on the irradiation wavelength. Structure of the Tl intensity spectrum of each sample is very similar to the structure of its optical absorption spectrum, indicating that at each wavelength, monochromatic radiation is absorbed to produce electronic transitions and electron hole pairs. Thermoluminescence of materials with thermal treatment at high temperature shows electron-hole trapping with less efficiency. The results show that Cu-doped alkali-halide materials are good detectors of a wide range of UV monochromatic radiations and could be used to measure UV radiation doses. (Author)

  18. Co-doping of Ag into Mn:ZnSe Quantum Dots: Giving Optical Filtering effect with Improved Monochromaticity.

    Science.gov (United States)

    Hu, Zhiyang; Xu, Shuhong; Xu, Xiaojing; Wang, Zhaochong; Wang, Zhuyuan; Wang, Chunlei; Cui, Yiping

    2015-10-08

    In optics, when polychromatic light is filtered by an optical filter, the monochromaticity of the light can be improved. In this work, we reported that Ag dopant atoms could be used as an optical filter for nanosized Mn:ZnSe quantum dots (QDs). If no Ag doping, aqueous Mn:ZnSe QDs have low monochromaticity due to coexisting of strong ZnSe band gap emission, ZnSe trap emission, and Mn dopant emission. After doping of Ag into QDs, ZnSe band gap and ZnSe trap emissions can be filtered, leaving only Mn dopant emission with improved monochromaticity. The mechanism for the optical filtering effect of Ag was investigated. The results indicate that the doping of Ag will introduce a new faster deactivation process from ZnSe conduction band to Ag energy level, leading to less electrons deactived via ZnSe band gap emission and ZnSe trap emission. As a result, only Mn dopant emission is left.

  19. Effect of Mg co-doping on cathodoluminescence properties of LuGAGG:Ce single crystalline garnet films

    Science.gov (United States)

    Schauer, P.; Lalinský, O.; Kučera, M.; Lučeničová, Z.; Hanuš, M.

    2017-10-01

    Mg2+ co-doped (LuGd)3(GaAl)5O12:Ce (LuGAGG:Ce,Mg) multicomponent single crystalline epitaxial garnet films were prepared and their cathodoluminescence (CL) and thermoluminescence (TSL) properties were studied in this paper. The films were prepared using the liquid phase epitaxy from lead-free BaO-B2O3-BaF2 flux and their scintillation properties were characterized using the 10 keV collimated e-beam. More specifically, temperature dependent CL intensity, CL emission spectra, CL decay characteristics as well as TSL emission characteristics of the mentioned films were measured. At the highest content of Mg (700 ppm), the CL decay time was as low as 28 ns and the CL afterglow was as low as 0.01% at 1 μs after the e-beam excitation cut-off, which are important parameters for electron detectors in e-beam devices. The CL temperature quenching of the studied films began above room temperature. An increase of Mg concentration to or above 280 ppm quenched the characteristic CL emission of LuGAGG:Ce,Mg. The TSL measurements show that the trap population in studied garnet samples is considerably suppressed. The LuGAGG:Ce,Mg multicomponent single crystalline epitaxial films were evaluated as the perspective fast scintillators for the electron detectors in the e-beam devices.

  20. Cathodoluminescence investigations on quartz cement in the sandstones of Khabour Formation from Iraqi Kurdistan Region, Northern Iraq

    Science.gov (United States)

    Omer, Muhamed F.; Friis, Henrik

    2014-03-01

    The Ordovician deltaic to shallow marine Khabour Formation in Northern Iraq consists mainly of sandstone with minor siltstone and interbedded shale. The sandstones are pervasively cemented by quartz that resulted in very little preserved primary porosity. Cathodoluminescence and petrographic studies showed that the silica cementation occurred in five successive phases which can be distinguished by their luminescence pattern. The precipitations of two phases have predated the major compaction process while the other phases are younger. The successive phases represent a sequence of changes in silica supply which were classified as very early and early, derived from dissolved biogenic silica that precipitated as opal/microquartz, possibly pre-compactional and of non-luminescent quartz overgrowth type. This was followed by phases whose silica supply derived from pressure solution of quartz, dissolution of feldspar, and hydrothermal fluids related to major thrust fault event. These successive quartz cement phases showed an increase in luminescence and the development of complicated zonation pattern in late-stage quartz cementation.

  1. High resolution cathodoluminescence spectroscopy of carbonate cementation in Khurmala Formation (Paleocene-L. Eocene) from Iraqi Kurdistan Region, Northern Iraq

    Science.gov (United States)

    Omer, Muhamed F.; Omer, Dilshad; Zebari, Bahroz Gh.

    2014-12-01

    A combination of high resolution cathodoluminsecnce-spectroscopy (HRS-CL) with spatial electron microprobe analysis and optical microscopy is used to determine paragenesis and history of cementation in the limestones and dolostones of Khurmala Formation which is exposed in many parts of Northern Iraq. Khurmala Formation was subjected to different diagenetic processes such as micritization, compaction, dissolution, neomorphism, pyritization and cementation that occurred during marine to shallow burial stages and culminated during intermediate to deep burial later stages. Five dolomite textures are recognized and classified according to crystal size distribution and crystal-boundary shape. Dolomitization is closely associated with the development of secondary porosity that pre-and postdates dissolution and corrosion; meanwhile such porosity was not noticed in the associated limestones. Microprobe analysis revealed three types of cement, calcite, dolomite and ankerite which range in their luminescence from dull to bright. Cathodoluminescence study indicated four main texture generations. These are (1) unzoned microdolomite of planar and subhedral shape, with syntaxial rim cement of echinoderm that show dull to red luminescence, (2) equant calcite cements filling interparticle pores which shows dull luminescence and weak zonal growth, (3.1) homogenous intrinsic blue stoichiometric calcite with dull luminescence and without activators, (3.2) coarse blocky calcite cement with strong oscillatory zoning and bright orange luminescence which postdates other calcite cements, (4) ankerite cement with red to orange, non-luminescence growth zonation which is the last formed cement.

  2. Cathodoluminescence Properties of Red-Emitting Sr{sub 1-x}Ca{sub x}S : Eu Phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young-Sik; Huh, Young-Duk [Dankook University, Yongin (Korea, Republic of)

    2016-07-15

    Sr{sub 1-x}Ca{sub x}S:Eu (x = 0, 0.2, 0.4, 0.6, 0.8, 1) phosphors were prepared from CaS, SrS, and EuS via a solid-state reaction in air. The cathodoluminescence (CL) spectra of the Sr{sub 1-x}Ca{sub x}S:Eu phosph ors for the moderate voltage ranging from 4 to 10 kV were obtained to test their usefulness in field emission displays (FEDs). The maximum wavelength of the CL spectra of the Sr{sub 1-x}Ca{sub x}S:Eu phosphors increases from 629 to 668 nm as the mole fraction of calcium increases up to x = 0.8, and then decreases to 663 nm at x = 1. The relationship between the CL spectra and crystal structures of the Sr{sub 1-x}Ca{sub x}S:Eu phosphors was determined.

  3. Influences of Interfacial Misfit Dislocations on Cathodoluminescence of ZnS/GaAs(001) Studied by Transmission Electron Microscopy

    Science.gov (United States)

    Mitsui, Tadashi; Yamamoto, Naoki

    2000-03-01

    The change in cathodoluminescence (CL) spectra of thin ZnS films grown by molecular beam epitaxy (MBE) on GaAs(001) has been examined by a low-temperature CL measurement system combined with a transmission electron microscope (TEM). It was found that structural defects such as dislocations and stacking faults formed in the ZnS films seriously affect CL intensity within a distance of 200 nm from the interface, and their effect becomes negligibly small at distances of more than 600 nm. The relative intensities of the exciton-associated emissions are small in comparison with the non-exciton-associated emissions for the thin samples that have relatively large stacking fault densities. This fact suggests that the stacking faults accompanying the partial dislocations suppress the generation of excitons. Moreover, the peak of the non-exciton-associated emission shifts markedly to long wavelengths, as the epitaxial layer thickness becomes less than 200 nm. The peak shift is attributed to the internal stress change in the ZnS film due to the stress caused by the lattice mismatch and the relaxation by the introduced defects.

  4. Cathodoluminescence Phenomena of Treated Rubies%优化处理红宝石的阴极发光特征

    Institute of Scientific and Technical Information of China (English)

    李敬敬

    2012-01-01

    使用阴极发光仪对热处理红宝石、染色处理红宝石、充填处理红宝石样品进行发光现象观察,并与天然红宝石、合成红宝石的阴极发光现象对比,得知优化红宝石的阴极发光现象与天然红宝石相近,而处理红宝石的发光强度比天然红宝石及合成红宝石要弱,但处理特征在阴极发光仪下清晰可见.%In this paper,experiments were made on series of rubies with the help of cathodoluminescence instrument;and luminous phenomena of heat-treated ruby,dyed ruby ,and filling processing ruby samples were discussed. Conclusions are drawn that luminous phenomenon of enhancing rubies is similar to that of natural rubies, yet luminous intensity of treated rubies is poorer than that of natural and synthetic rubies.

  5. Excitonic emission and N- and B-incorporation in homoepitaxial CVD-grown diamond investigated by cathodoluminescence

    Science.gov (United States)

    Araujo, D.; Kadri, M.; Wade, M.; Bustarret, E.; Deneuville, A.

    2005-03-01

    Diamond is a very large bandgap material arising high expectations either for optoelectronic applications or for active semiconducting layers in specific electronic devices to be used under extreme conditions of pressure, temperature, wear or radiation, as well as in chemically aggressive environments. Unintentionally boron-doped diamond layers were grown by microwave plasma-assisted chemical vapour deposition (CVD) on {001}-oriented undoped Ib substrates with the addition of oxygen gas during growth. The relative quantities of nitrogen and boron incorporated in the diamond lattice are evaluated by cathodoluminescence (CL) spectra recorded at 5 K. Two different effects are shown to limit nitrogen incorporation: the substrate crystalline quality and the addition of oxygen into the precursor during the growth. First, the CL spectra are shown to change strongly near the edges of the substrate in the regions corresponding to different bulk crystal growth modes. Some regions show a luminescence governed by UV emission while in other regions, where the H3 defect-related luminescence of the substrate is much stronger, the film UV emission is reduced. Second, the relative importance of the free exciton emission with respect to those from the nitrogen-related H3 centre and from the boron-bound exciton is shown to increase with the addition of oxygen during growth. Such observations are of first importance to improve the spectral emission and absorption threshold of the diamond material in the deep UV range.

  6. Cathodoluminescence, laser ablasion inductively coupled plasma mass spectrometry, electron probe microanalysis and electron paramagnetic resonance analyses of natural sphalerite

    Science.gov (United States)

    Karakus, M.; Hagni, R.D.; Koenig, A.; Ciftc, E.

    2008-01-01

    Natural sphalerite associated with copper, silver, lead-zinc, tin and tungsten deposits from various world-famous mineral deposits have been studied by cathodoluminescence (CL), laser ablasion inductively coupled plasma mass spectrometry (LA-ICP-MS), electron probe microanalysis (EPMA) and electron paramagnetic resonance (EPR) to determine the relationship between trace element type and content and the CL properties of sphalerite. In general, sphalerite produces a spectrum of CL colour under electron bombardment that includes deep blue, turquoise, lime green, yellow-orange, orange-red and dull dark red depending on the type and concentration of trace quantities of activator ions. Sphalerite from most deposits shows a bright yellow-orange CL colour with ??max centred at 585 nm due to Mn2+ ion, and the intensity of CL is strongly dependent primarily on Fe2+ concentration. The blue emission band with ??max centred at 470-490 nm correlates with Ga and Ag at the Tsumeb, Horn Silver, Balmat and Kankoy mines. Colloform sphalerite from older well-known European lead-zinc deposits and late Cretaceous Kuroko-type VMS deposits of Turkey shows intense yellowish CL colour and their CL spectra are characterised by extremely broad emission bands ranging from 450 to 750 nm. These samples are characterised by low Mn (behaviour of sphalerite serves to characterise ore types and help detect technologically important trace elements.

  7. Spatially resolved investigation of competing nanocluster emission in quantum-disks-in-nanowires structure characterized by nanoscale cathodoluminescence

    KAUST Repository

    Prabaswara, Aditya

    2017-06-30

    We report on the study and characterization of nanoclusters-related recombination centers within quantum-disks-in-nanowires heterostructure by utilizing microphotoluminescence (mu-PL) and cathodoluminescence scanning transmission electron microscopy (CL-STEM). mu-PL measurement shows that the nanoclusters-related recombination center exhibits different temperature-dependent characteristics compared with the surrounding InGaN quantum-disksrelated recombination center. CL-STEM measurements reveal that these recombination centers mainly arise from irregularities within the quantum disks, with a strong, spatially localized emission when measured at low temperature. The spectra obtained from both CL-STEM and mu-PL correlate well with each other. Our work sheds light on the optical and structural properties of simultaneously coexisting recombination centers within nanowires heterostructures. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

  8. Images

    Data.gov (United States)

    National Aeronautics and Space Administration — Images for the website main pages and all configurations. The upload and access points for the other images are: Website Template RSW images BSCW Images HIRENASD...

  9. Does pupil constriction under blue and green monochromatic light exposure change with age?

    Science.gov (United States)

    Daneault, Véronique; Vandewalle, Gilles; Hébert, Marc; Teikari, Petteri; Mure, Ludovic S; Doyon, Julien; Gronfier, Claude; Cooper, Howard M; Dumont, Marie; Carrier, Julie

    2012-06-01

    Many nonvisual functions are regulated by light through a photoreceptive system involving melanopsin-expressing retinal ganglion cells that are maximally sensitive to blue light. Several studies have suggested that the ability of light to modulate circadian entrainment and to induce acute effects on melatonin secretion, subjective alertness, and gene expression decreases during aging, particularly for blue light. This could contribute to the documented changes in sleep and circadian regulatory processes with aging. However, age-related modification in the impact of light on steady-state pupil constriction, which regulates the amount of light reaching the retina, is not demonstrated. We measured pupil size in 16 young (22.8±4 years) and 14 older (61±4.4 years) healthy subjects during 45-second exposures to blue (480 nm) and green (550 nm) monochromatic lights at low (7×10(12) photons/cm2/s), medium (3×10(13) photons/cm2/s), and high (10(14) photons/cm2/s) irradiance levels. Results showed that young subjects had consistently larger pupils than older subjects for dark adaptation and during all light exposures. Steady-state pupil constriction was greater under blue than green light exposure in both age groups and increased with increasing irradiance. Surprisingly, when expressed in relation to baseline pupil size, no significant age-related differences were observed in pupil constriction. The observed reduction in pupil size in older individuals, both in darkness and during light exposure, may reduce retinal illumination and consequently affect nonvisual responses to light. The absence of a significant difference between age groups for relative steady-state pupil constriction suggests that other factors such as tonic, sympathetic control of pupil dilation, rather than light sensitivity per se, account for the observed age difference in pupil size regulation. Compared to other nonvisual functions, the light sensitivity of steady-state pupil constriction appears to

  10. Human wavelength discrimination of monochromatic light explained by optimal wavelength decoding of light of unknown intensity.

    Directory of Open Access Journals (Sweden)

    Li Zhaoping

    Full Text Available We show that human ability to discriminate the wavelength of monochromatic light can be understood as maximum likelihood decoding of the cone absorptions, with a signal processing efficiency that is independent of the wavelength. This work is built on the framework of ideal observer analysis of visual discrimination used in many previous works. A distinctive aspect of our work is that we highlight a perceptual confound that observers should confuse a change in input light wavelength with a change in input intensity. Hence a simple ideal observer model which assumes that an observer has a full knowledge of input intensity should over-estimate human ability in discriminating wavelengths of two inputs of unequal intensity. This confound also makes it difficult to consistently measure human ability in wavelength discrimination by asking observers to distinguish two input colors while matching their brightness. We argue that the best experimental method for reliable measurement of discrimination thresholds is the one of Pokorny and Smith, in which observers only need to distinguish two inputs, regardless of whether they differ in hue or brightness. We mathematically formulate wavelength discrimination under this wavelength-intensity confound and show a good agreement between our theoretical prediction and the behavioral data. Our analysis explains why the discrimination threshold varies with the input wavelength, and shows how sensitively the threshold depends on the relative densities of the three types of cones in the retina (and in particular predict discriminations in dichromats. Our mathematical formulation and solution can be applied to general problems of sensory discrimination when there is a perceptual confound from other sensory feature dimensions.

  11. Does pupil constriction under blue and green monochromatic light exposure change with age?

    Science.gov (United States)

    Daneault, Véronique; Vandewalle, Gilles; Hébert, Marc; Teikari, Petteri; Mure, Ludovic S.; Doyon, Julien; Gronfier, Claude; Cooper, Howard M.; Dumont, Marie; Carrier, Julie

    2017-01-01

    Many non-visual functions are regulated by light through a photoreceptive system involving melanopsin-expressing retinal ganglion cells that are maximally sensitive to blue light. Several studies have suggested that the ability of light to modulate circadian entrainment and to induce acute effects on melatonin secretion, subjective alertness and gene expression, decreases during aging, particularly for blue light. This could contribute to the documented changes in sleep and circadian regulatory processes with aging. However, age-related modification in the impact of light on steady-state pupil constriction, which regulates the amount of light reaching the retina, is not demonstrated. We measured pupil size in 16 young (22.8±4y) and 14 older (61±4.4y) healthy subjects during 45s exposures to blue (480nm) and green (550nm) monochromatic lights at low (7×1012 photons/cm2/s), medium (3×1013 photons/cm2/s), and high (1014 photons/cm2/s) irradiance levels. Results showed that young subjects had consistently larger pupils than older subjects, for dark adaptation and during all light exposures. Steady-state pupil constriction was greater under blue than green light exposure in both age groups and increased with increasing irradiance. Surprisingly, when expressed in relation to baseline pupil size, no significant age-related differences were observed in pupil constriction. The observed reduction in pupil size in older individuals, both in darkness and during light exposure, may reduce retinal illumination and consequently affect non-visual responses to light. The absence of a significant difference between age groups for relative steady-state pupil constriction suggests that other factors such as tonic, sympathetic control of pupil dilation, rather than light sensitivity per se, account for the observed age difference in pupil size regulation. Compared to other nonvisual functions, the light sensitivity of steady-state pupil constriction appears to remain relatively

  12. Compact High-Repetition-Rate Monochromatic Terahertz Source Based on Difference Frequency Generation from a Dual-Wavelength Nd:YAG Laser and DAST Crystal

    Science.gov (United States)

    Zhong, Kai; Mei, Jialin; Wang, Maorong; Liu, Pengxiang; Xu, Degang; Wang, Yuye; Shi, Wei; Yao, Jianquan; Teng, Bing; Xiao, Yong

    2017-01-01

    Although high-repetition-rate dual-wavelength Nd:YAG lasers at 1319 and 1338 nm have been realized for quite a long time, we have employed it in generating monochromatic terahertz (THz) wave in this paper for the first time. The dual-wavelength laser was LD-end-pumped and acousto-optically (AO) Q-switched with the output power of watt level operating at different repetition rates from 5.5 to 30 kHz. Using a 0.6-mm-thick organic nonlinear crystal DAST for difference frequency generation (DFG), a compact terahertz source was achieved at 3.28 THz. The maximum average output power was about 0.58 μW obtained at a repetition rate of 5.5 kHz, corresponding to the conversion efficiency of about 6.4 × 10-7. The output power scaling is still feasible with higher pump power and a longer nonlinear DFG crystal. Owing to the compactness of the dual-wavelength laser and the nonlinear crystal, a palm-top terahertz source is expected for portable applications such as imaging and so on.

  13. Software for producing trichromatic images in astronomy

    CERN Document Server

    Morel, S; Morel, Sebastien; Davoust, Emmanuel

    1995-01-01

    We present a software package for combining three monochromatic images of an astronomical object into a trichromatic color image. We first discuss the meaning of "true" colors in astronomical images. We then describe the different steps of our method, choosing the relevant dynamic intensity range in each filter, inventorying the different colors, optimizing the color map, modifying the balance of colors, and enhancing contrasts at low intensity levels. While the first steps are automatic, the last two are interactive.

  14. Origin of ~2.5 Ga potassic granite from the Nellore Schist Belt, SE India: textural, cathodoluminescence, and SHRIMP U-Pb data

    Science.gov (United States)

    Vijaya Kumar, K.; Ernst, W. G.; Leelanandam, C.; Wooden, J. L.; Grove, M. J.

    2011-10-01

    In a geochemical and geochronological investigation of Archean and Proterozoic magmatism in the Nellore Schist Belt, we conducted SHRIMP U-Pb analyses of zircons from two cospatial granitic bodies at Guramkonda and Vendodu. The former is a Ba- and Sr-rich hornblende-bearing tonalite, whereas the latter is a Rb-, Zr-, Pb-, Th-, U-, and REE-rich biotite-bearing leucogranite. The Guramkonda tonalite displays a restitic texture with remnants of trapped granitic melt, whereas the Vendodu leucogranite contains residual/partially melted plagioclase grains. Both rock types contain two generations of zircon: tonalite contains a group of euhedral zoned zircons enclosed within plagioclase and a group of subhedral patchy zircons associated with trapped melt (quartz + feldspar matrix), and leucogranite also contains a group of doubly terminated euhedral zircons included within orthoclase as well as a group of zircons with visible cores mantled by later rim growth. Cathodoluminescence images also clearly document two distinctly textured varieties of zircon: the tonalite contains a population characterized by narrowly spaced uninterrupted oscillatory zoning and a second population lacking zoning but exhibiting a random distribution of dark (U-rich) and light (U-poor) regions; the leucogranite contains U-rich zoned zircons and U-poor zircon cores mantled by U-rich rims. The REE chemistry of zircon cores from the Vendodu leucogranite is very similar to the REE of zoned zircons from the Guramkonda tonalite. Zircon ages from both plutons exhibit bimodal distributions in U-Pb concordia diagrams. The tonalite defines an age of 2,521 Ma ± 5 Ma for zoned magmatic zircons and 2,485 Ma ± 5 Ma for unzoned newly precipitated zircons, whereas the leucogranite has an age of 2,518 Ma ± 5 Ma for U-poor zircon cores (relics of the tonalite pluton) and 2,483 Ma ± 3 Ma for U-rich zoned magmatic zircons. The trace element geochemistry of the ~2,520 Ma zircons is distinctly different from the ~2

  15. Three-dimensional point spread function measurements of imaging spectrometers

    Science.gov (United States)

    Jemec, Jurij; Pernuš, Franjo; Likar, Boštjan; Bürmen, Miran

    2017-09-01

    Measuring the three-dimensional point spread function (3D PSF) of imaging spectrometers is a challenging task since it requires a small, monochromatic and bright source. Here we introduce a powerful and practical new approach for 3D PSF measurement on the basis of a bright virtual monochromatic point-like source, which is formed by a collimated light beam and a convex spherical mirror. The effectiveness of the proposed methodology is demonstrated and discussed through 3D PSF measurements of an acousto-optic tunable filter based imaging spectrometer.

  16. Geochemistry, geochronology, and cathodoluminescence imagery of the Salihli and Turgutlu granites (central Menderes Massif, Western Turkey): Implications for Aegean tectonics

    Science.gov (United States)

    Catlos, E. J.; Baker, C.; Sorensen, S. S.; Çemen, I.; Hançer, M.

    2009-04-01

    The Menderes Massif (western Turkey) is an important metamorphic core complex located in the Aegean region; geochemical and geochronological data from this extensional domain facilitates our understanding of large-scale extension of the Earth's lithosphere. S-type, peraluminous granites (Salihli and Turgutlu) that intrude the Alasehir detachment which bounds the northern edge of the central Menderes Massif may have been generated due to subduction of the Eastern Mediterranean floor along the Hellenic trench. In situ Th-Pb ion microprobe monazite ages from the granites range from 21.7±4.5 Ma to 9.6±1.6 Ma (±1s). The range is consistent with cathodoluminescence (CL) imagery that document complex textures within the samples. Salihli and Turgutlu granites share many similar characteristics, including multiple generations of plagioclase (some with shocked cores consistent with magma mixing), plagioclase replacing K-feldspar and the development of myrmekite, clear evidence for fluid infiltration, and multiple generations of microcracks and microfaults. The granites may have evolved from compositionally distinct magma sources, as Salihli samples in general contain allanite as the major accessory mineral, whereas Turgutlu granites contain monazite. However, the CL imagery document similar alteration textures. Ages reported here are similar to dates constraining extension reported elsewhere in the Aegean, but indicate a level of complexity when linking movement within the Menderes Massif to the large-scale geodynamic processes that created other metamorphic core complexes in the region. Difficulties exist in linking the ages obtained from the granites to specific tectonic events due to the presence of secondary alteration textures, generations of mineral growth, and multiple episodes of deformation.

  17. Carbonate cements and grains in submarine fan sandstones—the Cergowa Beds (Oligocene, Carpathians of Poland) recorded by cathodoluminescence

    Science.gov (United States)

    Pszonka, Joanna; Wendorff, Marek

    2017-01-01

    The cathodoluminescence (CL) observations with cold cathode, supplemented by reconnaissance scanning electron microscope analyses, bring new data on petrology, provenance and diagenesis of the Oligocene-age Cergowa sandstones from the Outer Carpathians (SE Poland). The sandstones represent a variety of mass gravity flow sediments deposited on a submarine fan, which now forms a lenticular lithosome—a part of the Menilite Beds-Krosno Beds suite important for the hydrocarbons industry. The most common components of the Cergowa sandstones observed under the CL are carbonates—cement and grains that are mainly represented by lithoclasts. Carbonate cement is represented by five generations: brown (Cb), orange (Co), yellow (Cy), zoned (Cz) and black (Ck). Pore-filling Cb and Co calcite cements are interpreted as genetically related to eo- and mesodiagenetic phases. The mesodiagenetic phase is characterised by randomly distributed relatively large monocrystalline-zoned rhombs of dolomite cement (Cz) and ankerite/ferroan dolomite (Ck). The telodiagenetic phase is represented by pore-filling yellow calcite (Cy) that crystallised under the influence of suboxic meteoric waters. Lithoclasts represent six microfacies of carbonate rocks eroded in the source area, i.e. microbreccia, tectonised immature calcarenite/wacke, microsparite, sparite, biomicrosparite/packstone and dolostone. Pronounced indentations of terrigenous sand grains into intraclasts of packstone/biomicrosparite, coupled with commonly present similar packstone-type matrix, suggest that a significant part of matrix resulted from compaction of soft biomicrosparite grains. Terrigenous grains bound by calcite cement are commonly corroded by acidic diagenetic fluids, and partial or even complete replacement of silicates by calcite and clay minerals is illustrated here by feldspar grains. Substantial carbonate cementation has resulted in both the significant hardness and abrasion resistance of the Cergowa sandstones

  18. Visualizing trace element distribution in quartz using cathodoluminescence, electron microprobe, and laser ablation-inductively coupled plasma-mass spectrometry

    Science.gov (United States)

    Rusk, Brian; Koenig, Alan; Lowers, Heather

    2011-01-01

    Cathodoluminescent (CL) textures in quartz reveal successive histories of the physical and chemical fluctuations that accompany crystal growth. Such CL textures reflect trace element concentration variations that can be mapped by electron microprobe or laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Trace element maps in hydrothermal quartz from four different ore deposit types (Carlin-type Au, epithermal Ag, porphyry-Cu, and MVT Pb-Zn) reveal correlations among trace elements and between trace element concentrations and CL textures. The distributions of trace elements reflect variations in the physical and chemical conditions of quartz precipitation. These maps show that Al is the most abundant trace element in hydrothermal quartz. In crystals grown at temperatures below 300 °C, Al concentrations may vary by up to two orders of magnitude between adjacent growth zones, with no evidence for diffusion. The monovalent cations Li, Na, and K, where detectable, always correlate with Al, with Li being the most abundant of the three. In most samples, Al is more abundant than the combined total of the monovalent cations; however, in the MVT sample, molar Al/Li ratios are ~0.8. Antimony is present in concentrations up to ~120 ppm in epithermal quartz (~200–300 °C), but is not detectable in MVT, Carlin, or porphyry-Cu quartz. Concentrations of Sb do not correlate consistently with those of other trace elements or with CL textures. Titanium is only abundant enough to be mapped in quartz from porphyry-type ore deposits that precipitate at temperatures above ~400 °C. In such quartz, Ti concentration correlates positively with CL intensity, suggesting a causative relationship. In contrast, in quartz from other deposit types, there is no consistent correlation between concentrations of any trace element and CL intensity fluctuations.

  19. Wave-flume experiments of soft-rock cliff erosion under monochromatic waves

    Science.gov (United States)

    Regard, Vincent; Astruc, Dominique; Caplain, Bastien

    2017-04-01

    We investigate how cliffs erode under wave attack. Rocky coast erosion works through cycles, each one corresponding to three successive phases: (i) notch creation at cliff toe by mechanical action of waves, (ii) cliff fracturation leading to collapse, and (iii) evacuation of scree aprons by waves and currents. We performed experiments in a 5m x 14cm x 25cm wave flume (15 cm water depth) to investigate how waves are eroding a rocky coast. The cliff is made of wet sand and models a relatively soft rock. We used 3 different grain size (D50 = 0.28-0.41-0.48 mm), changing the cliff rheology. Waves are monochromatic; their height and period differ for the various experiments. Actual wave parameters are estimated by capacitive probes located offshore. The experiments are monitored by two video cameras both on the side and above the flume. Pictures are taken at a rate of 1Hz during the first 4h and then the rate is decreased to 0.1Hz till the end of experiment (about 1 day). The monitoring ensure a confident characterization of experiments in terms of waves (surf similarity parameter ξ and the incident wave energy flux F) and in terms of sediment (Dean number Ω and Shields number θb at breakers). Experiments begin by an initial phase of quick cliff retreat. Then the system evolves with slower cliff retreat. We focus on bottom morphology which we characterize in function of wave forcing (ξ, F). We show that the bottom morphology mainly depends on ξ. For our reference sediment (Dm = 0.41 mm), we observed: (i) surging breakers on a steep terrace (type T1) for ξ > 0.65; (ii)collapsing breakers on a bared profile attached to the inner platform (type T2) for 0.55< ξ <0.6; (iii) spilling breakers on gentle terrace (type T3) for F < 1.3 W/m and 0.55< ξ <0.6. Another bottom morphology, type T4, displays two sub-systems, an outer system with a double-bar profile where breaking waves are plunging, and an inner system with a T1, T2 or T3 profile. Some of these bottom

  20. Effect of monochromatic and combined light colour on performance, blood parameters, ovarian morphology and reproductive hormones in laying hens

    Directory of Open Access Journals (Sweden)

    Md. Rakibul Hassan

    2013-07-01

    Full Text Available We evaluated the effect of monochromatic and combined light emitting diode (LED light colour on performance, ovarian morphology, and reproductive hormone and biochemical blood parameters in laying hens. A total of 600 Hy-line Brown pullets, 12 weeks of age, were divided (25×4×6 = birds × replications × treatments as follows: red (R, green (G, blue (B, and combinations of R→G and R→G→B treatments. Fluorescent white light (W was the control. The results showed that higher egg production was found under the monochromatic R and combination R→G treatments, and that heavier eggs were laid by the B and G treatments (P<0.05. Consequently, better feed conversion ratio was attained in the R→G treatment. Serum follicle stimulating hormone and 17β-estradiol levels were significantly higher in the R and R→G treatments. B treated birds came into production 15 days later than those treated with R light. Organ weight (ovary and stroma and ovarian follicle numbers (1-3 and 4-6 mm were significantly higher in R treated birds, as well as serum glucose and triglyceride contents. Serum IgG concentrations and the heterophil to lymphocyte ratio were not influenced by light colour. In these laying hens, 14 h R with 2 h G light in the later part of the day increased reproductive hormone levels, ovarian weight, and follicle number and hence increased egg production. Thus, these results suggest that a combination of R→G light may be comparable with monochromatic R light to enhance egg production in laying hens.

  1. Steady state of a low-density ensemble of atoms in a monochromatic field taking into account recoil effects

    Science.gov (United States)

    Prudnikov, O. N.; Il'enkov, R. Ya.; Taichenachev, A. V.; Tumaikin, A. M.; Yudin, V. I.

    2011-06-01

    A method has been developed for obtaining the steady-state solution of a quantum kinetic equation for the atomic density matrix in an arbitrarily polarized monochromatic field with the complete inclusion of recoil effects and degeneracy of atomic levels in the projection of the angular momentum. This method makes it possible to obtain the most general solution beyond the previously accepted approximations (semiclassical approximation, secular approximation, etc.). In particular, it has been shown that the laser cooling temperature is a function of not only the depth of the optical potential (as was previously thought), but also the mass of an atom.

  2. Amplified spontaneous emission spectrum at the output of a diode amplifier saturated by an input monochromatic wave

    Science.gov (United States)

    Bogatov, A. P.; Drakin, A. E.; D'yachkov, N. V.; Gushchik, T. I.

    2016-08-01

    Expressions for the amplitudes of amplified spontaneous emission waves in a diode amplifier near the frequency ω0 of a 'strong' input monochromatic wave have been derived in terms of a random function of a stationary Gaussian process. We have found expressions for the spectral density of the amplitudes and shown that, on the red side of the spectrum with respect to frequency ω0, spontaneous emission waves obtain additional nonlinear gain, induced by the strong wave, whereas on the blue side of the spectrum an additional loss is induced. Such behaviour of the amplitudes of amplified waves agrees with previous results.

  3. Hydrothermal Evolution of the Giant Cenozoic Kadjaran porphyry Cu-Mo deposit, Tethyan metallogenic belt, Armenia, Lesser Caucasus: mineral paragenetic, cathodoluminescence and fluid inclusion constraints

    Science.gov (United States)

    Hovakimyan, Samvel; Moritz, Robert; Tayan, Rodrik; Rezeau, Hervé

    2016-04-01

    stockwork. One of them is the east-west-oriented 6th vein zone in the northern part of the deposit, which contains quartz-molybdenite veins and late quartz-galena-sphalerite veins. This is interpreted as a telescoping between porphyry and epithermal environments. It is supported by microscopic studies of mineral paragenesis, which reveal the presence of enargite and tennantite-tetrahedrite, luzonite, sphalerite, and galena, generally in a gangue of quartz, followed by a late carbonate and gypsum stage. On-going fluid inclusion studies are being carried out on quartz samples from the different mineralization stages. Five types of fluid inclusions were distinguished according to their nature, bubble size, and daughter mineral content: vapor-rich, aqueous-carbonic, brine, polyphase brine and liquid-rich inclusions. Cathodoluminescence images from the porphyry veins reveal four generations of quartz. Molybdenite and chalcopyrite are associated with two different dark luminescent quartz generations, which contain typical brine, aqueous-carbonic and vapour-rich H2O fluid inclusions, with some of them coexisting locally as boiling assemblages. Epithermal veins are mainly characterized by liquid-rich H2O fluid inclusions. Microthermometric studies of fluid inclusions reveal a major difference in homogenisation temperatures between the early quartz-molybdenite- chalcopyrite stage (Thtotal between 3600 and 4250C) and the late quartz-galena-sphalerite vein stage (Thtotal 300-2700C), which is attributed to the transition from a porphyry to an epithermal environment in the Kadjaran deposit.

  4. The effect of pupil size on stimulation of the melanopsin containing retinal ganglion cells, as evaluated by monochromatic pupillometry

    DEFF Research Database (Denmark)

    Nissen, Claus Jeppe; Sander, Birgit; Lund-Andersen, Henrik

    2012-01-01

    Purpose: To evaluate the influence of the size of the light exposed pupil in one eye on the pupillary light reflex of the other eye. Method: Using a monochromatic pupillometer, the left eye in each of 10 healthy subjects was exposed to 20¿s of monochromatic light of luminance 300¿cd/m(2), first red...... (660¿nm) and in a following session, blue (470¿nm) light. The consensual pupillary diameter in the right eye was continuously measured before, during, and after light exposure. Subsequently, Tropicamide 1% or Pilocarpine 2% was instilled into the left eye and when the pupil was either maximally dilated...... or contracted, the entire sequence of red and blue light exposure repeated. After at least 3¿days, when the effect of the eye drop had subsided, the entire experiment was repeated, this time employing the other substance. Results: Prior dilatation of the left pupil augmented the post light contraction to blue...

  5. Analysis of gas exchange, stomatal behaviour and micronutrients uncovers dynamic response and adaptation of tomato plants to monochromatic light treatments.

    Science.gov (United States)

    O'Carrigan, Andrew; Babla, Mohammad; Wang, Feifei; Liu, Xiaohui; Mak, Michelle; Thomas, Richard; Bellotti, Bill; Chen, Zhong-Hua

    2014-09-01

    Light spectrum affects the yield and quality of greenhouse tomato, especially over a prolonged period of monochromatic light treatments. Physiological and chemical analysis was employed to investigate the influence of light spectral (blue, green and red) changes on growth, photosynthesis, stomatal behaviour, leaf pigment, and micronutrient levels. We found that plants are less affected under blue light treatment, which was evident by the maintenance of higher A, gs, Tr, and stomatal parameters and significantly lower VPD and Tleaf as compared to those plants grown in green and red light treatments. Green and red light treatments led to significantly larger increase in the accumulation of Fe, B, Zn, and Cu than blue light. Moreover, guard cell length, width, and volume all showed highly significant positive correlations to gs, Tr and negative links to VPD. There was negative impact of monochromatic lights-induced accumulation of Mn, Cu, and Zn on photosynthesis, leaf pigments and plant growth. Furthermore, most of the light-induced significant changes of the physiological traits were partially recovered at the end of experiment. A high degree of morphological and physiological plasticity to blue, green and red light treatments suggested that tomato plants may have developed mechanisms to adapt to the light treatments. Thus, understanding the optimization of light spectrum for photosynthesis and growth is one of the key components for greenhouse tomato production.

  6. Measurement of Monochromatic Emissivity of Cement Clinker with Various Fe2O3 Content at High Temperature

    Institute of Scientific and Technical Information of China (English)

    Z.J.Ye; C.F.Ma; 等

    1996-01-01

    An applicatiopn of the optical pyrometer is studied for measuring monochromatic emissivities of cement clinker with various Fe2O3 contnet.The idsa of using “brightness temperature” is introduced into the eimssivity measurement.In this method,there is no need for measuring an actual temperature of sample surfaces,only with determining both brightness temperatures of a sample and a blackbody can the required emissivity be evaluated according to Wien's radiation law.In practice,the cement clinker is regarded as a greybody,the monochromatic emissivity is approximately equal to the total emissivity,so a single-colour optical pyrometer is applied for this purpose,Test measurements are carried out on 10 kinds of cement clinkers,Experimental data are treated by the least square method.As a result ,the emissivity variation with temperature at a certain Fe2O3 content is quite well represented by εn=a+bT.Furthermore,this work first reported that the eimissivities of cement clinker change consierably with Fe2O3 contents.In multiple cement production this conclusion is very important.

  7. Cathodoluminescence and micro-structural evidence for crystallisation and deformation processes of granites in the Eastern Lachlan Fold Belt (SE Australia)

    Science.gov (United States)

    Müller, Axel; Lennox, Paul; Trzebski, Robert

    2002-05-01

    Trace elements (Al, K, Ti, Fe), growth and deformation pattern in quartz of the multiple deformed Carcoar, Barry and Sunset Hills granites were investigated by electron micro probe and cathodoluminescence. Zoned quartz phenocrysts with high Ti concentrations (>70 ppm) that show blue cathodoluminescence originated from the early stage of magma crystallisation. Multiple deformation of quartz causes the redistribution of Al and K in the quartz lattice, which results in the accumulation of these elements in submicroscopic inclusions (Carcoar and Barry granodiorites and Sunset Hills granite were intruded in the Late Ordovician-Early Silurian at depths of 4-8.6 and 10-12 km, respectively. In contrast to the continuous crystallisation of the granodiorite magmas, the magma of the Sunset Hills granite ascended in a stepwise fashion, causing multiple quartz nucleation. The two granodiorites were multiple, post-magmatically deformed, first, during Early Devonian under more brittle conditions at temperatures of 350-400 °C, whereas the Sunset Hills granite experienced more ductile deformation at temperatures of around 550 °C.

  8. Deciphering igneous and metamorphic events in high-grade rocks of the Wilmington complex, Delaware: Morphology, cathodoluminescence and backscattered electron zoning, and SHRIMP U-Pb geochronology of zircon and monazite

    Science.gov (United States)

    Aleinikoff, J.N.; Schenck, W.S.; Plank, M.O.; Srogi, L.A.; Fanning, C.M.; Kamo, S.L.; Bosbyshell, H.

    2006-01-01

    High-grade rocks of the Wilmington Complex, northern Delaware and adjacent Maryland and Pennsylvania, contain morphologically complex zircons that formed through both igneous and metamorphic processes during the development of an island-arc complex and suturing of the arc to Laurentia. The arc complex has been divided into several members, the protoliths of which include both intrusive and extrusive rocks. Metasedimentary rocks are interlayered with the complex and are believed to be the infrastructure upon which the arc was built. In the Wilmingto n Complex rocks, both igneous and metamorphic zircons occur as elongate and equant forms. Chemical zoning, shown by cathodoluminescence (CL), includes both concentric, oscillatory patterns, indicative of igneous origin, and patchwork and sector patterns, suggestive of metamorphic growth. Metamorphic monazites are chemically homogeneous, or show oscillatory or spotted chemical zoning in backscattered electron images. U-Pb geochronology by sensitive high resolution ion microprobe (SHRIMP) was used to date complexly zoned zircon and monazite. All but one member of the Wilmington Complex crystallized in the Ordovician between ca. 475 and 485 Ma; these rocks were intruded by a suite of gabbro-to-granite plutonic rocks at 434 ?? Ma. Detrital zircons in metavolcanic and metasedimentary units were derived predominantly from 0.9 to 1.4 Ga (Grenvillian) basement, presumably of Laurentian origin. Amphibolite to granulite facies metamorphism of the Wilmington Complex, recorded by ages of metamorphic zircon (428 ?? 4 and 432 ?? 6 Ma) and monazite (429 ?? 2 and 426 ?? 3 Ma), occurred contemporaneously with emplacement of the younger plutonic rocks. On the basis of varying CL zoning patterns and external morphologies, metamorphic zircons formed by different processes (presumably controlled by rock chemistry) at slightly different times and temperatures during prograde metamorphism. In addition, at least three other thermal episodes are

  9. Coupling between creep and redox behavior in nickel - yttria stabilized zirconia observed in-situ by monochromatic neutron imaging

    DEFF Research Database (Denmark)

    Makowska, Malgorzata Grazyna; Kuhn, Luise Theil; Frandsen, Henrik Lund

    2017-01-01

    Ni-YSZ (nickel - yttria stabilized zirconia) is a material widely used for electrodes and supports in solid oxide electrochemical cells. The mechanical and electrochemical performance of these layers, and thus the whole cell, depends on their microstructure. During the initial operation of a cell...

  10. Effect of Monochromatic Light on Expression of Estrogen Receptor (ER) and Progesterone Receptor (PR) in Ovarian Follicles of Chicken.

    Science.gov (United States)

    Liu, Lingbin; Li, Diyan; Gilbert, Elizabeth R; Xiao, Qihai; Zhao, Xiaoling; Wang, Yan; Yin, Huadong; Zhu, Qing

    2015-01-01

    Artificial illumination is widely used in modern poultry houses and different wavelengths of light affect poultry production and behaviour. In this study, we measure mRNA and protein abundance of estrogen receptors (ERs) and progesterone receptors (PRs) in order to investigate the effect of monochromatic light on egg production traits and gonadal hormone function in chicken ovarian follicles. Five hundred and fifty-two 19-wk-old laying hens were exposed to three monochromatic lights: red (RL; 660 nm), green (GL; 560 nm), blue (BL; 480 nm) and control cool white (400-760 nm) light with an LED (light-emitting diode). There were 4 identical light-controlled rooms (n = 138) each containing 3 replicate pens (46 birds per pen). Water was supplied ad libitum and daily rations were determined according to the nutrient suggestions for poultry. Results showed that under BL conditions there was an increase in the total number of eggs at 300 days of age and egg-laying rate during the peak laying period. The BL and GL extended the duration of the peak laying period. Plasma melatonin was lowest in birds reared under BL. Plasma estradiol was elevated in the GL-exposed laying hens, and GL and BL increased progesterone at 28 wk of age. In the granulosa layers of the fifth largest preovulatory follicle (F5), the third largest preovulatory follicle (F3) and the largest preovulatory follicle (F1), ERα mRNA was increased by BL and GL. Treatment with BL increased ERβ mRNA in granulosa layers of F5, F3 and F1, while GL increased ERβ mRNA in F5 and F3. There was a corresponding increase in abundance of the proteins in the granulosa layers of F5, with an increase in PR-B, generated via an alternative splice site, relative to PR-A. Treatment with BL also increased expression of PR mRNA in all of the granulosa layers of follicles, while treatment with GL increased expression of PR mRNA in granulosa layers of SYF(small yellow follicle), F5 and F1. These results indicate that blue and green

  11. Effect of Monochromatic Light on Expression of Estrogen Receptor (ER and Progesterone Receptor (PR in Ovarian Follicles of Chicken.

    Directory of Open Access Journals (Sweden)

    Lingbin Liu

    Full Text Available Artificial illumination is widely used in modern poultry houses and different wavelengths of light affect poultry production and behaviour. In this study, we measure mRNA and protein abundance of estrogen receptors (ERs and progesterone receptors (PRs in order to investigate the effect of monochromatic light on egg production traits and gonadal hormone function in chicken ovarian follicles. Five hundred and fifty-two 19-wk-old laying hens were exposed to three monochromatic lights: red (RL; 660 nm, green (GL; 560 nm, blue (BL; 480 nm and control cool white (400-760 nm light with an LED (light-emitting diode. There were 4 identical light-controlled rooms (n = 138 each containing 3 replicate pens (46 birds per pen. Water was supplied ad libitum and daily rations were determined according to the nutrient suggestions for poultry. Results showed that under BL conditions there was an increase in the total number of eggs at 300 days of age and egg-laying rate during the peak laying period. The BL and GL extended the duration of the peak laying period. Plasma melatonin was lowest in birds reared under BL. Plasma estradiol was elevated in the GL-exposed laying hens, and GL and BL increased progesterone at 28 wk of age. In the granulosa layers of the fifth largest preovulatory follicle (F5, the third largest preovulatory follicle (F3 and the largest preovulatory follicle (F1, ERα mRNA was increased by BL and GL. Treatment with BL increased ERβ mRNA in granulosa layers of F5, F3 and F1, while GL increased ERβ mRNA in F5 and F3. There was a corresponding increase in abundance of the proteins in the granulosa layers of F5, with an increase in PR-B, generated via an alternative splice site, relative to PR-A. Treatment with BL also increased expression of PR mRNA in all of the granulosa layers of follicles, while treatment with GL increased expression of PR mRNA in granulosa layers of SYF(small yellow follicle, F5 and F1. These results indicate that blue

  12. Monochromatic backlighting of direct-drive cryogenic DT implosions on OMEGA

    Science.gov (United States)

    Stoeckl, C.; Epstein, R.; Betti, R.; Bittle, W.; Delettrez, J. A.; Forrest, C. J.; Glebov, V. Yu.; Goncharov, V. N.; Harding, D. R.; Igumenshchev, I. V.; Jacobs-Perkins, D. W.; Janezic, R. T.; Kelly, J. H.; Kosc, T. Z.; McCrory, R. L.; Michel, D. T.; Mileham, C.; McKenty, P. W.; Marshall, F. J.; Morse, S. F. B.; Regan, S. P.; Radha, P. B.; Rice, B.; Sangster, T. C.; Shoup, M. J.; Shmayda, W. T.; Sorce, C.; Theobald, W.; Ulreich, J.; Wittman, M. D.; Meyerhofer, D. D.; Frenje, J. A.; Gatu Johnson, M.; Petrasso, R. D.

    2017-05-01

    Backlighting is a powerful technique to observe the flow of cold and dense material in high-energy-density-plasma experiments. High-performance, direct-drive cryogenic deuterium-tritium (DT) implosions are a challenging backlighting configuration because of the low opacity of the DT shell, the high shell velocity, the small size of the stagnating shell, and the very bright self-emission of the hot core. A crystal imaging system with a Si Heα backlighter at 1.865 keV driven by ˜20-ps short pulses from OMEGA EP was developed to radiograph the OMEGA cryogenic implosions. The high throughput of the crystal imaging system makes it possible to record high-quality images with good photon statistics and a spatial resolution of ˜15 μm at 10% to 90% modulation. This imager has been used to study the evolution of preimposed mass-density perturbations in the ablator, to quantify the perturbations caused by the stalk that is used to mount the target, and to study the mix caused by laser imprint or small-scale debris on the target surface. Because of the very low opacity of DT relative to carbon, even 0.1% of mix of carbon into the DT ice can be reliably inferred from the images. With the current implosion designs, mix is only observed for an adiabat below α = 4.

  13. "How to" incorporate dual-energy imaging into a high volume abdominal imaging practice.

    Science.gov (United States)

    Tamm, Eric P; Le, Ott; Liu, Xinming; Layman, Rick R; Cody, Dianna D; Bhosale, Priya R

    2017-03-01

    Dual-energy CT imaging has many potential uses in abdominal imaging. It also has unique requirements for protocol creation depending on the dual-energy scanning technique that is being utilized. It also generates several new types of images which can increase the complexity of image creation and image interpretation. The purpose of this article is to review, for rapid switching and dual-source dual-energy platforms, methods for creating dual-energy protocols, different approaches for efficiently creating dual-energy images, and an approach to navigating and using dual-energy images at the reading station all using the example of a pancreatic multiphasic protocol. It will also review the three most commonly used types of dual-energy images: "workhorse" 120kVp surrogate images (including blended polychromatic and 70 keV monochromatic), high contrast images (e.g., low energy monochromatic and iodine material decomposition images), and virtual unenhanced images. Recent developments, such as the ability to create automatically on the scanner the most common dual-energy images types, namely new "Mono+" images for the DSDECT (dual-source dual-energy CT) platform will also be addressed. Finally, an approach to image interpretation using automated "hanging protocols" will also be covered. Successful dual-energy implementation in a high volume practice requires careful attention to each of these steps of scanning, image creation, and image interpretation.

  14. Cathodoluminescence plasmon microscopy

    NARCIS (Netherlands)

    Kuttge, M.

    2009-01-01

    Surface plasmon polaritons (SPPs) are electromagnetic waves that are strongly coupled to the collective oscillation of free electrons at an interface between a dielectric and a metal. Strong confinement of the electromagnetic field and tunability of SPP dispersion allow two-dimensional optics. This

  15. Cylindrical shock waves in rotational axisymmetric non-ideal dusty gas with increasing energy under the action of monochromatic radiation

    Science.gov (United States)

    Sahu, P. K.

    2017-08-01

    The propagation of a cylindrical shock wave in a rotational axisymmetric non-ideal dusty gas under the action of monochromatic radiation with increasing energy, which has variable azimuthal and axial components of fluid velocity, is investigated. The dusty gas is assumed to be a mixture of non-ideal (or perfect) gas and small solid particles, in which solid particles are continuously distributed. Similarity solutions are obtained as well as the effects of the variation of the radiation parameters, the parameter of non-idealness of the gas, the mass concentration of solid particles in the mixture, the ratio of the density of solid particles to the initial density of the gas, and the piston velocity index are worked out in detail. The total energy of the shock wave is varying and increases with time. It is observed that the radiation parameter and the piston velocity index have opposite behaviour on the flow variables as well as the shock strength.

  16. Influence of monochromatic light on quality traits, nutritional, fatty acid, and amino acid profiles of broiler chicken meat.

    Science.gov (United States)

    Kim, M J; Parvin, R; Mushtaq, M M H; Hwangbo, J; Kim, J H; Na, J C; Kim, D W; Kang, H K; Kim, C D; Cho, K O; Yang, C B; Choi, H C

    2013-11-01

    The role of monochromatic lights was investigated on meat quality in 1-d-old straight-run broiler chicks (n = 360), divided into 6 light sources with 6 replicates having 10 chicks in each replicate. Six light sources were described as incandescent bulbs (IBL, as a control) and light-emitting diode (LED) light colors as white light (WL), blue light, red light (RL), green light, and yellow light. Among LED groups, the RL increased the concentration of monounsaturated fatty acids (P light produced by LED responded similar to the IBL light in influencing nutrient contents of meat. Moreover, LED is not decisive in improving fatty acid composition of meat. However, the role of IBL in reducing n-6:n-3 ratio and enhancing n-3 cannot be neglected. Among LED, WL is helpful in improving essential and nonessential amino acid contents of broiler meat.

  17. Role of monochromatic light on daily variation of clock gene expression in the pineal gland of chick.

    Science.gov (United States)

    Jiang, Nan; Wang, Zixu; Cao, Jing; Dong, Yulan; Chen, Yaoxing

    2016-11-01

    The avian pineal gland is a master clock that can receive external photic cues and translate them into output rhythms. To clarify whether a shift in light wavelength can influence the circadian expression in chick pineal gland, a total of 240 Arbor Acre male broilers were exposed to white light (WL), red light (RL), green light (GL) or blue light (BL). After 2weeks light illumination, circadian expressions of seven core clock genes in pineal gland and the level of melatonin in plasma were examined. The results showed after illumination with monochromatic light, 24h profiles of all clock gene mRNAs retained circadian oscillation, except that RL tended to disrupt the rhythm of cCry2. Compared to WL, BL advanced the acrophases of the negative elements (cCry1, cCry2, cPer2 and cPer3) by 0.1-1.5h and delayed those of positive elements (cClock, cBmal1 and cBmal2) by 0.2-0.8h. And, RL advanced all clock genes except cClock and cPer2 by 0.3-2.1h, while GL delayed all clock genes by 0.5-1.5h except cBmal2. Meanwhile, GL increased the amplitude and mesor of positive and reduced both parameters of negative clock genes, but RL showed the opposite pattern. Although the acrophase of plasma melatonin was advanced by both GL and RL, the melatonin level was significantly increased in GL and decreased in RL. This tendency was consistent with the variations in the positive clock gene mRNA levels under monochromatic light and contrasted with those of negative clock genes. Therefore, we speculate that GL may enhance positive clock genes expression, leading to melatonin synthesis, whereas RL may enhance negative genes expression, suppressing melatonin synthesis. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Effects of monochromatic light sources on sex hormone levels in serum and on semen quality of ganders.

    Science.gov (United States)

    Chang, Shen-Chang; Zhuang, Zi-Xuan; Lin, Min-Jung; Cheng, Chuen-Yu; Lin, Tsung-Yi; Jea, Yu-Shine; Huang, San-Yuan

    2016-04-01

    Light is an essential external factor influencing various physiological processes, including reproductive performance, in birds. Although several attempts have been made to understand the effect of light on poultry production, the effect of light of a particular wavelength (color) on the reproductive function in geese remains unclear. This study evaluated the effect of various monochromatic light sources on the levels of sex hormone and on semen quality of ganders. Of 30 male White Roman geese in their third reproductive season (average age=3 years), 27 were divided into three groups receiving monochromatic white or red or blue lights. The birds were kept in an environmentally controlled house with a lighting photoperiod of 7L:17D for six weeks as the adaptation period. The photoperiod was subsequently changed to 9L:15D and maintained for 24 weeks. Three ganders at the beginning of the study and three from each group at the end of the adjusting period and the 20th and 30th week of the study period were sacrificed, and their testes and blood samples were collected for determining the sex hormone levels. Semen samples were collected for determining semen quality parameters, including the semen collection index, sperm concentration, semen volume, sperm motility, sperm viability, sperm morphology, and semen quality factor. The results showed that the testosterone and estradiol levels remained unchanged in all three groups at all time points. The ratio of testosterone to estradiol of ganders exposed to white light was significantly higher than that of ganders exposed to red light at the 30th week (Plight were significantly the lowest (Plight were the highest (Plight may maintain a better semen quality than that with red or blue lights in ganders.

  19. Close Up of Monochromatic Aberrations Using Snell's Law: An Undergraduate Computational Experiment

    Science.gov (United States)

    Levesque, L.

    2009-01-01

    Images formed from light rays refracting a spherical surface are often introduced in textbooks using the paraxial approximation. Incoming rays propagating from the object meeting the surface of a transparent medium at a given point for which the angle is larger than 15 degrees with respect to the normal are not described accurately from the…

  20. Close Up of Monochromatic Aberrations Using Snell's Law: An Undergraduate Computational Experiment

    Science.gov (United States)

    Levesque, L.

    2009-01-01

    Images formed from light rays refracting a spherical surface are often introduced in textbooks using the paraxial approximation. Incoming rays propagating from the object meeting the surface of a transparent medium at a given point for which the angle is larger than 15 degrees with respect to the normal are not described accurately from the…

  1. Ultrahigh-resolution optical coherence tomography with monochromatic and chromatic aberration correction.

    Science.gov (United States)

    Zawadzki, Robert J; Cense, Barry; Zhang, Yan; Choi, Stacey S; Miller, Donald T; Werner, John S

    2008-05-26

    We have developed an improved adaptive optics - optical coherence tomography (AO-OCT) system and evaluated its performance for in vivo imaging of normal and pathologic retina. The instrument provides unprecedented image quality at the retina with isotropic 3D resolution of 3.5 x 3.5 x 3.5 microm(3). Critical to the instrument's resolution is a customized achromatizing lens that corrects for the eye's longitudinal chromatic aberration and an ultra broadband light source (Delta lambda=112 nm lambda(0)= approximately 836 nm). The eye's transverse chromatic aberrations is modeled and predicted to be sufficiently small for the imaging conditions considered. The achromatizing lens was strategically placed at the light input of the AO-OCT sample arm. This location simplifies use of the achromatizing lens and allows straightforward implementation into existing OCT systems. Lateral resolution was achieved with an AO system that cascades two wavefront correctors, a large stroke bimorph deformable mirror (DM) and a micro-electromechanical system (MEMS) DM with a high number of actuators. This combination yielded diffraction-limited imaging in the eyes examined. An added benefit of the broadband light source is the reduction of speckle size in the axial dimension. Additionally, speckle contrast was reduced by averaging multiple B-scans of the same proximal patch of retina. The combination of improved micron-scale 3D resolution, and reduced speckle size and contrast were found to significantly improve visibility of microscopic structures in the retina.

  2. Improvement of the tuneable monochromatic gamma-ray source at the 15 MeV linac of the University of Gent

    Science.gov (United States)

    Masschaele, B.; Jolie, J.; Mondelaers, W.; Materna, T.; Cauwels, P.; Dierick, M.

    2001-07-01

    It is shown how the tuneable gamma-ray source based on a bremsstrahlung source and a crystal, diffracting in Cauchois geometry, can be made intense and monochromatic using an asymmetrically cut Si crystal. The results and implications are here presented.

  3. Effect of monochromatic light stimuli during embryogenesis on muscular growth, chemical composition, and meat quality of breast muscle in male broilers.

    Science.gov (United States)

    Zhang, L; Zhang, H J; Qiao, X; Yue, H Y; Wu, S G; Yao, J H; Qi, G H

    2012-04-01

    This study was conducted to evaluate the effect of monochromatic light stimuli during embryogenesis on breast muscle growth, chemical composition, and meat quality of male broilers. Fertile broiler eggs (Arbor Acres; n = 1,320) were preweighed and randomly assigned to 1 of 3 treatment groups in 3 modified incubators: 1) control group (in dark condition), 2) monochromatic green light group (560 nm), and 3) monochromatic blue light group (480 nm). The monochromatic lighting systems sourced from light-emitting diode lamps and were equalized at the intensity of 15 lx at eggshell level. After hatch, 120 male chicks from each group were placed in 6 replicates with 20 birds each. All of the birds were housed under white light (30 lx at bird-head level) with a light schedule of 23L:1D. At 21, 35, and 42 d of age, BW and breast muscle weight in the green light group were significantly increased compared with birds in the blue or dark groups (P dark condition or blue group at 42 d of market age (P dark condition (P 0.05). Green light stimuli tended to increase cooking loss (P = 0.08) and L* value of 24-h meat color (P = 0.09). These results suggest that green light stimuli during embryogenesis enhanced the posthatch BW of male broilers, increased breast muscle growth, and improved the feed conversion ratio, but it did not cause any noticeable changes in breast chemical composition or overall meat quality characteristics.

  4. Sensitivity and specificity of monochromatic photography of the ocular fundus in differentiating optic nerve head drusen and optic disc oedema: optic disc drusen and oedema.

    Science.gov (United States)

    Gili, Pablo; Flores-Rodríguez, Patricia; Yangüela, Julio; Orduña-Azcona, Javier; Martín-Ríos, María Dolores

    2013-03-01

    Evaluation of the efficacy of monochromatic photography of the ocular fundus in differentiating optic nerve head drusen (ONHD) and optic disc oedema (ODE). Sixty-six patients with ONHD, 31 patients with ODE and 70 healthy subjects were studied. Colour and monochromatic fundus photography with different filters (green, red and autofluorescence) were performed. The results were analysed blindly by two observers. The sensitivity, specificity and interobserver agreement (k) of each test were assessed. Colour photography offers 65.5 % sensitivity and 100 % specificity for the diagnosis of ONHD. Monochromatic photography improves sensitivity and specificity and provides similar results: green filter (71.20 % sensitivity, 96.70 % specificity), red filter (80.30 % sensitivity, 96.80 % specificity), and autofluorescence technique (87.8 % sensitivity, 100 % specificity). The interobserver agreement was good with all techniques used: autofluorescence (k = 0.957), green filter (k = 0.897), red filter (k = 0.818) and colour (k = 0.809). Monochromatic fundus photography permits ONHD and ODE to be differentiated, with good sensitivity and very high specificity. The best results were obtained with autofluorescence and red filter study.

  5. Direct evidence of single quantum dot emission from GaN islands formed at threading dislocations using nanoscale cathodoluminescence: A source of single photons in the ultraviolet

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Gordon, E-mail: Gordon.Schmidt@ovgu.de; Berger, Christoph; Veit, Peter; Metzner, Sebastian; Bertram, Frank; Bläsing, Jürgen; Dadgar, Armin; Strittmatter, André; Christen, Jürgen [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, 39106 Magdeburg (Germany); Callsen, Gordon; Kalinowski, Stefan; Hoffmann, Axel [Institute of Solid State Physics, Technical University Berlin, 10623 Berlin (Germany)

    2015-06-22

    Intense emission from GaN islands embedded in AlN resulting from GaN/AlN quantum well growth is directly resolved by performing cathodoluminescence spectroscopy in a scanning transmission electron microscope. Line widths down to 440 μeV are measured in a wavelength region between 220 and 310 nm confirming quantum dot like electronic properties in the islands. These quantum dot states can be structurally correlated to islands of slightly enlarged thicknesses of the GaN/AlN quantum well layer preferentially formed in vicinity to dislocations. The quantum dot states exhibit single photon emission in Hanbury Brown-Twiss experiments with a clear antibunching in the second order correlation function at zero time delay.

  6. Chemical and physical studies of chondrites. X - Cathodoluminescence and phase composition studies of metamorphism and nebular processes in chondrules of type 3 ordinary chondrites

    Science.gov (United States)

    Dehart, John M.; Lofgren, Gary E.; Jie, LU; Benoit, Paul H.; Sears, Derek W. G.

    1992-01-01

    The cathodoluminescence (CL) characteristics of eight type-3 ordinary chondrites and one L5 chondrite were investigated with particular emphasis on detailed compositions of the relevant phases in four of these chondrites: Semarkona (type-3.0); Krymka (3.1); Allan Hills A77214 (3.5); and Dhajala (3.8). By sorting the chondrules into eight groups according to the CL of mesostasis and to certain compositional criteria and by determining the number of chondrules in these groups as a function of petrological type, it was possible to deduce genetic/evolutionary sequences of the chondrules. It is shown that there are major compositional differences in chondrules, which account for their CL properties and the chondrule groups.

  7. Preliminary Application of High-Definition CT Gemstone Spectral Imaging in Hand and Foot Tendons

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Kai; Zhang, Cheng Qi; Li, Wei; Wang, Xin Yi; Pang, Tao Peng; Wang, Guang Li [Dept. of Medical Imaging, Qianfoshan Hospital Affiliated to Shandong University, Jinan (China); Wang, Jun Jun [The Medical College of Shandong University, Jinan (China); Lui, Cheng [CT Room, Shandong Medical Imaging Research Institute, Jinan (China)

    2012-11-15

    To assess the feasibility of visualizing hand and foot tendon anatomy and disorders by Gemstone Spectral Imaging (GSI) high-definition CT (HDCT). Thirty-five patients who suffered from hand or foot pain were scanned with GSI mode HDCT and MRI. Spectrum analysis was used to select the monochromatic images that provide the optimal contrast-to-noise ratio (CNR) for tendons. The image quality at the best selected monochromatic level and the conventional polychromatic images were compared. Tendon anatomy and disease were also analyzed at GSI and MRI. The monochromatic images at about 65 keV (mean 65.09 {+-} 2.98) provided the optimal CNR for hand and foot tendons. The image quality at the optimal selected monochromatic level was superior to conventional polychromatic images (p = 0.005, p < 0.05). GSI was useful in visualizing hand and foot tendon anatomy and disorders. There were no statistical differences between GSI and MRI with regard to tendon thickening (X{sup 2} = 0, p > 0.05), compression (X{sup 2} = 0.5, p > 0.05), absence (X{sup 2} = 0, p > 0.05) and rupture (X{sup 2} = 0, p > 0.05). GSI was significantly less sensitive than MRI in displaying tendon adhesion (X{sup 2} = 4.17, p < 0.05), degeneration (X{sup 2} = 4.17, p < 0.05), and tendinous sheath disease (X{sup 2} = 10.08, p < 0.05). GSI with monochromatic images at 65 keV displays clearly the most hand and foot tendon anatomy and disorders with image quality improved, as compared with conventional polychromatic images. It may be used solely or combined with MRI in clinical work, depending on individual patient disease condition.

  8. Time reversal of continuous-wave, monochromatic signals in elastic media

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Brian E [Los Alamos National Laboratory; Guyer, Robert A [Los Alamos National Laboratory; Ulrich, Timothy J [Los Alamos National Laboratory; Johnson, Paul A [Los Alamos National Laboratory

    2009-01-01

    Experimental observations of spatial focusing of continuous-wave, steady-state elastic waves in a reverberant elastic cavity using time reversal are reported here. Spatially localized focusing is achieved when multiple channels are employed, while a single channel does not yield such focusing. The amplitude of the energy at the focal location increases as the square of the number of channels used, while the amplitude elsewhere in the medium increases proportionally with the number of channels used. The observation is important in the context of imaging in solid laboratory samples as well as problems involving continuous-wave signals in Earth.

  9. Automatic spectral imaging protocol selection and iterative reconstruction in abdominal CT with reduced contrast agent dose: initial experience

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Peijie; Liu, Jie; Chai, Yaru; Yan, Xiaopeng; Gao, Jianbo; Dong, Junqiang [The First Affiliated Hospital of Zhengzhou University, Department of Radiology, Zhengzhou, Henan Province (China)

    2017-01-15

    To evaluate the feasibility, image quality, and radiation dose of automatic spectral imaging protocol selection (ASIS) and adaptive statistical iterative reconstruction (ASIR) with reduced contrast agent dose in abdominal multiphase CT. One hundred and sixty patients were randomly divided into two scan protocols (n = 80) each; protocol A, 120 kVp/450 mgI/kg, filtered back projection algorithm (FBP); protocol B, spectral CT imaging with ASIS and 40 to 70 keV monochromatic images generated per 300 mgI/kg, ASIR algorithm. Quantitative parameters (image noise and contrast-to-noise ratios [CNRs]) and qualitative visual parameters (image noise, small structures, organ enhancement, and overall image quality) were compared. Monochromatic images at 50 keV and 60 keV provided similar or lower image noise, but higher contrast and overall image quality as compared with 120-kVp images. Despite the higher image noise, 40-keV images showed similar overall image quality compared to 120-kVp images. Radiation dose did not differ between the two protocols, while contrast agent dose in protocol B was reduced by 33 %. Application of ASIR and ASIS to monochromatic imaging from 40 to 60 keV allowed contrast agent dose reduction with adequate image quality and without increasing radiation dose compared to 120 kVp with FBP. (orig.)

  10. [Imaging].

    Science.gov (United States)

    Chevrot, A; Drapé, J L; Godefroy, D; Dupont, A M; Pessis, E; Sarazin, L; Minoui, A

    1997-01-01

    The panoply of imaging techniques useful in podology is essentially limited to X-rays. Standard "standing" and "lying" X-rays furnish most of the required information. Arthrography is sometimes performed, in particular for trauma or tumour of the ankle. CT scan and MRI make a decisive contribution in difficult cases, notably in fractures and in small fractures without displacement. The two latter techniques are useful in tendon, ligament and muscular disorders, where echography is also informative. Rigorous analysis of radiographies and a good knowledge of foot disorders make these imaging techniques efficacious.

  11. Light-dependent magnetoreception in birds: increasing intensity of monochromatic light changes the nature of the response

    Directory of Open Access Journals (Sweden)

    Bischof Hans-Joachim

    2007-02-01

    Full Text Available Abstract Background The Radical Pair model proposes that magnetoreception is a light-dependent process. Under low monochromatic light from the short-wavelength part of the visual spectrum, migratory birds show orientation in their migratory direction. Under monochromatic light of higher intensity, however, they showed unusual preferences for other directions or axial preferences. To determine whether or not these responses are still controlled by the respective light regimes, European robins, Erithacus rubecula, were tested under UV, Blue, Turquoise and Green light at increasing intensities, with orientation in migratory direction serving as a criterion whether or not magnetoreception works in the normal way. Results The birds were well oriented in their seasonally appropriate migratory direction under 424 nm Blue, 502 nm Turquoise and 565 nm Green light of low intensity with a quantal flux of 8·1015 quanta s-1 m-2, indicating unimpaired magnetoreception. Under 373 nm UV of the same quantal flux, they were not oriented in migratory direction, showing a preference for the east-west axis instead, but they were well oriented in migratory direction under UV of lower intensity. Intensities of above 36·1015 quanta s-1 m-2 of Blue, Turquoise and Green light elicited a variety of responses: disorientation, headings along the east-west axis, headings along the north-south axis or 'fixed' direction tendencies. These responses changed as the intensity was increased from 36·1015 quanta s-1 m-2 to 54 and 72·1015 quanta s-1 m-2. Conclusion The specific manifestation of responses in directions other than the migratory direction clearly depends on the ambient light regime. This implies that even when the mechanisms normally providing magnetic compass information seem disrupted, processes that are activated by light still control the behavior. It suggests complex interactions between different types of receptors, magnetic and visual. The nature of the

  12. Brain responses to violet, blue, and green monochromatic light exposures in humans: prominent role of blue light and the brainstem.

    Directory of Open Access Journals (Sweden)

    Gilles Vandewalle

    Full Text Available BACKGROUND: Relatively long duration retinal light exposure elicits nonvisual responses in humans, including modulation of alertness and cognition. These responses are thought to be mediated in part by melanopsin-expressing retinal ganglion cells which are more sensitive to blue light than violet or green light. The contribution of the melanopsin system and the brain mechanisms involved in the establishment of such responses to light remain to be established. METHODOLOGY/PRINCIPAL FINDINGS: We exposed 15 participants to short duration (50 s monochromatic violet (430 nm, blue (473 nm, and green (527 nm light exposures of equal photon flux (10(13ph/cm(2/s while they were performing a working memory task in fMRI. At light onset, blue light, as compared to green light, increased activity in the left hippocampus, left thalamus, and right amygdala. During the task, blue light, as compared to violet light, increased activity in the left middle frontal gyrus, left thalamus and a bilateral area of the brainstem consistent with activation of the locus coeruleus. CONCLUSION/SIGNIFICANCE: These results support a prominent contribution of melanopsin-expressing retinal ganglion cells to brain responses to light within the very first seconds of an exposure. The results also demonstrate the implication of the brainstem in mediating these responses in humans and speak for a broad involvement of light in the regulation of brain function.

  13. Computer simulations on resonant fluorescence spectra in atomic gases in two monochromatic laser fields of arbitrary intensity and magnetic field

    Science.gov (United States)

    Karagodova, Tamara Y.

    1996-03-01

    In the intense radiation fields with power density from 104W/cm2 to 109W/cm2 the essential modification of electronic states of atoms occurs displaying, in particular, in modifications of resonant fluorescence (rf) spectra. We use 'Fermi golden rule' for calculations of relative intensities and frequencies for rf multiplet for real multilevel initially unexcited atoms in two monochromatic laser fields of arbitrary intensity resonant to adjacent transitions of (Xi) or (Lambda) types and magnetic field, giving the level splittings of different values from Zeeman to Paschen-Back effect. The dependence of quasienergies on parameters obtained with the help of a sorting program permits us to define the values of parameters for which the states of the system are mixed and so to receive the correct probability amplitudes for instantaneous or adiabatic regimes of switching the perturbation. The analysis of the quasienergies and form of rf spectra permits us to get relations between the form of the spectra and modifications of electronic structure of the atom due to radiation fields and external magnetic field.

  14. Spitzer Analysis of HII Region Complexes in the Magellanic Clouds: Determining a Suitable Monochromatic Obscured Star Formation Indicator

    CERN Document Server

    Lawton, Brandon; Babler, Brian; Block, Miwa; Bolatto, Alberto D; Bracker, Steve; Carlson, Lynn R; Engelbracht, Charles W; Hora, Joseph L; Indebetouw, Remy; Madden, Suzanne C; Meade, Marilyn; Meixner, Margaret; Misselt, Karl; Oey, M S; Oliveira, Joana M; Robitaille, Thomas; Sewilo, Marta; Shiao, Bernie; Vijh, Uma P; Whitney, Barbara

    2010-01-01

    HII regions are the birth places of stars, and as such they provide the best measure of current star formation rates (SFRs) in galaxies. The close proximity of the Magellanic Clouds allows us to probe the nature of these star forming regions at small spatial scales. We aim to determine the monochromatic IR band that most accurately traces the bolometric IR flux (TIR), which can then be used to estimate an obscured SFR. We present the spatial analysis, via aperture/annulus photometry, of 16 LMC and 16 SMC HII region complexes using the Spitzer IRAC and MIPS bands. UV rocket data and SHASSA H-alpha data are also included. We find that nearly all of the LMC and SMC HII region SEDs peak around 70um, from ~10 to ~400 pc from the central sources. As a result, the sizes of HII regions as probed by 70um is approximately equal to the sizes as probed by TIR (about 70 pc in radius); the radial profile of the 70um flux, normalized by TIR, is constant at all radii (70um ~ 0.45 TIR); the 1-sigma standard deviation of the 7...

  15. An alignment method for the ATLAS end-cap TRT detector using a narrow monochromatic X-ray beam

    CERN Document Server

    Åkesson, T; Dixon, N; Dolgoshein, B A; Eerola, Paule Anna Mari; Farthouat, Philippe; Fedin, O; Froidevaux, Daniel; Gavrilenko, I; Hajduk, Z; Hauviller, Claude; Ivanov, V; Ivochkin, V G; Jelamkov, A; Konovalov, S V; Lichard, P; Lundberg, B; Muraviev, S; Nadtochy, A; Nevski, P; Peshekhonov, V D; Platonov, Yu P; Price, M; Romaniouk, A; Shchegelskii, V; Shmeleva, A; Smirnov, A; Smirnov, S; Sosnovtsev, V V

    2001-01-01

    The end-cap transition radiation tracker (TRT), consisting of 36 modules (wheels), is being constructed as a part of the ATLAS Inner Detector at the CERN LHC. This paper describes a method for determining the wire positions inside the straw proportional tubes (SPT), which are the basic building blocks of the ATLAS TRT, with an accuracy of better than 10 mu m. The procedure involves moving a narrow monochromatic X-ray beam across the straw and measuring the counting rate as a function of the position of the X-ray beam in the straw. To achieve this goal, a beam directing device (BDD), providing the possibility to direct the X-ray beam in a chosen direction within some solid angle and supplying an accurate angular measurement system, has been constructed. The results of the wire position measurements performed using this BDD on a full-scale mechanical prototype end-cap wheel of the TRT are presented in this paper. (11 refs).

  16. Successful treatment with 308-nm monochromatic excimer light and subsequent tacrolimus 0.03% ointment in refractory plasma cell cheilitis.

    Science.gov (United States)

    Yoshimura, Kazuhiro; Nakano, Shunji; Tsuruta, Daisuke; Ohata, Chika; Hashimoto, Takashi

    2013-06-01

    Plasma cell cheilitis is a chronic inflammatory disease that presents with erythema, erosions, ulcers and occasional nodules within the mucosa, including the lips. It is histopathologically characterized by dense plasma cell infiltration in the lamina propria of the mucous membranes. Several treatments for plasma cell cheilitis have been reported, including topical steroids, topical antibiotics or topical tacrolimus. However, 308-nm monochromatic excimer light (MEL) has never been reported as a treatment option, while it was reported to be very effective in treating erosive oral lichen planus. We report a 62-year-old man who had chronic plasma cell cheilitis on the lower lip, which was refractory to topical and systemic corticosteroid. The lesion and severe pain were significantly improved by the treatment with nine sessions of 308-nm MEL twice per week with a total dose of 1120 mJ/cm(2). However, the lesion gradually worsened after treatment frequency was reduced to once per month. Subsequent tacrolimus 0.03% ointment cleared the lesion completely in a month and no recurrence was observed a year later. Refractory plasma cell cheilitis and concomitant severe pain quickly responded to 308-nm MEL when administrated twice per week. Because the long interval between each MEL treatment seemed ineffective to improve the lesion, appropriate frequency and adequate total dose of MEL treatment may be necessary for a successful treatment.

  17. The Effect of Monochromatic Infrared Photo Energy on the Irritability of Myofascial Trigger Spot of Rabbit Skeletal Muscle

    Directory of Open Access Journals (Sweden)

    Ta-Shen Kuan

    2015-01-01

    Full Text Available Objective. To determine whether the vasodilatation effect of monochromatic infrared photo energy (MIRE had the potential for the treatment of myofascial trigger spot (MTrS in rabbits. Design. A randomized-controlled animal study. Subjects. Twelve adult New Zealand rabbits. Methods. For each rabbit, a MTrS (equivalent to a myofascial trigger point in humans in one side of the biceps femoris muscle was randomly selected for MIRE treatment (experimental side, while another MTrS in the other side (control side received a sham treatment. The intervention consisted of a daily 40 minutes treatment, three times per week for 2 weeks. The prevalence of endplate noise (EPN loci in the MTrS was assessed before, immediately after, and one week after the completion of the 2-week treatment. Results. MIRE could suppress the prevalence of EPN in the MTrS. The degree of reduction in EPN prevalence in the MTrS between the experimental side and the control side was significantly different immediately after MIRE treatment, but not significantly different one week after MIRE treatment. Conclusion. Our study suggests that MIRE may be a useful therapeutic option for the management of the myofascial trigger point in humans.

  18. Application of FEL technique for constructing high-intensity, monochromatic, polarized gamma-sources at storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Saldin, E.L.; Schneidmiller, E.A.; Ulyanov, Yu.N. [Automatic Systems Corporation, Samara (Russian Federation)] [and others

    1995-12-31

    A possibility to construct high-intensity tunable monochromatic{gamma}-source at high energy storage rings is discussed. It is proposed to produce {gamma}-quanta by means of Compton backscattering of laser photons on electrons circulating in the storage. The laser light wavelength is chosen in such a way that after the scattering, the electron does not leave the separatrix. So as the probability of the scattering is rather small, energy oscillations are damped prior the next scattering. As a result, the proposed source can operate in {open_quotes}parasitic{close_quote} mode not interfering with the main mode of the storage ring operation. Analysis of parameters of existent storage rings (PETRA, ESRF, Spring-8, etc) shows that the laser light wavelength should be in infrared, {lambda}{approximately} 10 - 400 {mu}m, wavelength band. Installation at storage rings of tunable free-electron lasers with the peak and average output power {approximately} 10 MW and {approximately} 1 kW, respectively, will result in the intensity of the {gamma}-source up to {approximately} 10{sup 14}s{sup -1} with tunable {gamma}-quanta energy from several MeV up to several hundreds MeV. Such a {gamma}-source will reveal unique possibilities for precision investigations in nuclear physics.

  19. Emission properties of hydrothermal Yb{sup 3+}, Er{sup 3+} and Yb{sup 3+}, Tm{sup 3+}-codoped Lu{sub 2}O{sub 3} nanorods: upconversion, cathodoluminescence and assessment of waveguide behavior

    Energy Technology Data Exchange (ETDEWEB)

    Barrera, Elixir William; Pujol, MarIa Cinta; DIaz, Francesc [Fisica i Cristal.lografia de Materials, Universitat Rovira i Virgili, Campus Sescelades c/ Marcel.lI Domingo s/n, E-43007 Tarragona (Spain); Choi, Soo Bong; Rotermund, Fabian [Division of Energy Systems Research, Ajou University, 443-749 Suwon (Korea, Republic of); Park, Kyung Ho [Korea Advanced Nano Fab Center, 443-270 Suwon (Korea, Republic of); Jeong, Mun Seok [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, 500-712 Gwangju (Korea, Republic of); Cascales, Concepcion, E-mail: ccascales@icmm.csic.es [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones CientIficas, c/Sor Juana Ines de la Cruz, 3 Cantoblanco, E-28049 Madrid (Spain)

    2011-02-18

    Yb{sup 3+} and Ln{sup 3+} (Ln{sup 3+} = Er{sup 3+} or Tm{sup 3+}) codoped Lu{sub 2}O{sub 3} nanorods with cubic Ia3-bar symmetry have been prepared by low temperature hydrothermal procedures, and their luminescence properties and waveguide behavior analyzed by means of scanning near-field optical microscopy (SNOM). Room temperature upconversion (UC) under excitation at 980 nm and cathodoluminescence (CL) spectra were studied as a function of the Yb{sup +} concentration in the prepared nanorods. UC spectra revealed the strong development of Er{sup 3+4}F{sub 9/2} {yields} 4I{sub 15/2} (red) and Tm{sup 3+1}G{sub 4} {yields} {sup 3}H{sub 6} (blue) bands, which became the pre-eminent and even unique emissions for corresponding nanorods with the higher Yb{sup 3+} concentration. Favored by the presence of large phonons in current nanorods, UC mechanisms that privilege the population of {sup 4}F{sub 9/2} and {sup 1}G{sub 4} emitting levels through phonon-assisted energy transfer and non-radiative relaxations account for these observed UC luminescence features. CL spectra show much more moderate development of the intensity ratio between the Er{sup 3+4}F{sub 9/2} {yields}{sup 4}I{sub 15/2} (red) and {sup 2}H{sub 11/2}, {sup 4}S{sub 3/2} {yields} {sup 4}I{sub 15/2} (green) emissions with the increase in the Yb{sup 3+} content, while for Yb{sup 3+}, Tm{sup 3+}-codoped Lu{sub 2}O{sub 3} nanorods the dominant CL emission is Tm{sup 3+1}D{sub 2} {yields} {sup 3}F{sub 4} (deep-blue). Uniform light emission along Yb{sup 3+}, Er{sup 3+}-codoped Lu{sub 2}O{sub 3} rods has been observed by using SNOM photoluminescence images; however, the rods seem to be too thin for propagation of light.

  20. Preliminary experimental study and simulation of an energy-tunable quasi-monochromatic laser-Compton X/γ-ray source

    Institute of Scientific and Technical Information of China (English)

    LUO We; XU Wang; ZHUO Hong-Bin; MA Yan-Yun

    2012-01-01

    We propose a slanting collision scheme for Compton scattering of a laser light against a relativistic electron beam.This scheme is suitable to generate an energy-tunable X/γ-ray source.In this paper,we present theoretical study and simulation of the spectral,spatial and temporal characteristics of such a source.We also describe two terms laser-Compton scattering (LCS) experiments at the 100 MeV Linac of Shanghai Institute of Applied Physics,where quasi-monochromatic LCS X-ray energy spectra with peak energies of ~30 keV are observed successfully.These preliminary investigations are carried out to understand the feasibility of developing an energy-tunable quasi-monochromatic X/γ-ray source,the future Shanghai Laser Electron Gamma Source.

  1. Stimulation with monochromatic green light during incubation alters satellite cell mitotic activity and gene expression in relation to embryonic and posthatch muscle growth of broiler chickens.

    Science.gov (United States)

    Zhang, L; Zhang, H J; Wang, J; Wu, S G; Qiao, X; Yue, H Y; Yao, J H; Qi, G H

    2014-01-01

    Previous studies showed that monochromatic green light stimuli during embryogenesis accelerated posthatch body weight (BW) and pectoral muscle growth of broilers. In this experiment, we further investigated the morphological and molecular basis of this phenomenon. Fertile broiler eggs (Arbor Acres, n=880) were pre-weighed and randomly assigned to 1 of the 2 incubation treatment groups: (1) dark condition (control group), and (2) monochromatic green light group (560 nm). The monochromatic lighting systems sourced from light-emitting diode lamps and were equalized at the intensity of 15 lx at eggshell level. The dark condition was set as a commercial control from day 1 until hatching. After hatch, 120 male 1-day-old chicks from each group were housed under incandescent white light with an intensity of 30 lx at bird-head level. No effects of light stimuli during embryogenesis on hatching time, hatchability, hatching weight and bird mortality during the feeding trial period were observed in the present study. Compared with the dark condition, the BW, pectoral muscle weight and myofiber cross-sectional areas were significantly greater on 7-day-old chicks incubated under green light. Green light also increased the satellite cell mitotic activity of pectoral muscle on 1- and 3-day-old birds. In addition, green light upregulated MyoD, myogenin and myostatin mRNA expression in late embryos and/ or newly hatched chicks. These data suggest that stimulation with monochromatic green light during incubation promote muscle growth by enhancing proliferation and differentiation of satellite cells in late embryonic and newly hatched stages. Higher expression of myostatin may ultimately help prevent excessive proliferation and differentiation of satellite cells in birds incubated under green light.

  2. Can AERONET data be used to accurately model the monochromatic beam and circumsolar irradiances under cloud-free conditions in desert environment?

    Directory of Open Access Journals (Sweden)

    Y. Eissa

    2015-07-01

    Full Text Available Routine measurements of the beam irradiance at normal incidence (DNI include the irradiance originating from within the extent of the solar disc only (DNIS whose angular extent is 0.266° ± 1.7 %, and that from a larger circumsolar region, called the circumsolar normal irradiance (CSNI. This study investigates if the spectral aerosol optical properties of the AERONET stations are sufficient for an accurate modelling of the monochromatic DNIS and CSNI under cloud-free conditions in a desert environment. The data from an AERONET station in Abu Dhabi, United Arab Emirates, and a collocated Sun and Aureole Measurement (SAM instrument which offers reference measurements of the monochromatic profile of solar radiance, were exploited. Using the AERONET data both the radiative transfer models libRadtran and SMARTS offer an accurate estimate of the monochromatic DNIS, with a relative root mean square error (RMSE of 5 %, a relative bias of +1 % and acoefficient of determination greater than 0.97. After testing two configurations in SMARTS and three in libRadtran for modelling the monochromatic CSNI, libRadtran exhibits the most accurate results when the AERONET aerosol phase function is presented as a Two Term Henyey–Greenstein phase function. In this case libRadtran exhibited a relative RMSE and a bias of respectively 22 and −19 % and a coefficient of determination of 0.89. The results are promising and pave the way towards reporting the contribution of the broadband circumsolar irradiance to standard DNI measurements.

  3. Analysis of monochromatic signals by using data from the detector of Allegro gravitational waves; Analise de sinais monocromaticos utilizando dados do detector de ondas gravitacionais Allegro

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Fernanda Gomes de

    2010-07-01

    The present work is developed in the searching for monochromatic gravitational waves signals in ALLEGRO's data. We have two procedures for data analysis based on the periodogram of Welch, which a method for the detection of monochromatic signals in the middle of noise which basically makes power spectrum estimates using averaged modified periodograms. By using this method it was possible to obtain a power spectrum for the data which reinforce peaks due to monochromatic signals. The two procedures of analysis for the years 1997 and 1999, were focused on monitoring a peak that appears in the spectral density of ALLEGRO's detector, so called 'mystery mode' (near 887 Hz). We look for variations in the frequency of the mystery mode that agree with the variation of the Doppler effect. In the rst analysis we have used by the variation of daily and annual Doppler shift. For the second one, we have only searched annual Doppler shift. We have applied the periodogram of Welch in both tests in the raw data of the detector in the search for a real signal and we found some peaks that can be candidates of gravitational radiation only the second analysis. In order to test the method we used in both analysis a simulated gravitational wave signal modulated by the Doppler effect injected in the data. We detected in both methods the artificial signal of GW simulated. Therefore we have reason to conclude that both methods are efficient in the search for monochromatic signals. (author)

  4. 1D Modeling of a Bifacial Silicon Solar Cell under Frequency Modulation Monochromatic Illumination: Determination of the Equivalent Electrical Circuit Related to the Surface Recombination Velocity

    Directory of Open Access Journals (Sweden)

    H. Ly Diallo

    2012-06-01

    Full Text Available We present in this study the determination of the equivalent electrical circuits associated to the recombination velocities for a bifacial silicon solar cell under frequency modulation and monochromatic illumination. This determination is based on Bode and Nyquist diagrams that is the variations of the phase and the module of the back surface and intrinsic junction recombination velocities. Their dependence on illumination wavelength is also shown.

  5. Disposal of metal artifacts by monochrome virtual images generated by TC dual power planning in radiation therapy; Eliminacion de artefactos metalicos mediante imagenes virtuales nonocromaticas generadas mediante TC de energia dual para planificacion en radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Perez, V.; Bartres Salido, A.; Arana Fernandez Moya, E.; Crispin Contreras, V.; Dolores Alemany, V. de los; Campo Sanmartin, V.; Moratal Perez, D.

    2015-07-01

    Using monochromatic high-energy virtual images reconstructed by a scanner TCED is viable for planning radiotherapy treatments and improves image quality. Such images using the DICOM standard, and have been successfully exported to the planning system XiO treatments. (Author)

  6. Local and Systemic Cardiovascular Effects from Monochromatic Infrared Therapy in Patients with Knee Osteoarthritis: A Double-Blind, Randomized, Placebo-Controlled Study

    Directory of Open Access Journals (Sweden)

    Ru-Lan Hsieh

    2012-01-01

    Full Text Available Infrared (IR therapy is used for pain relief in patients with knee osteoarthritis (OA. However, IR’s effects on the cardiovascular system remain uncertain. Therefore, we investigated the local and systemic cardiovascular effects of monochromatic IR therapy on patients with knee OA in a double-blind, randomized, placebo-controlled study. Seventy-one subjects with knee OA received one session of 40 min of active or placebo monochromatic IR treatment (with power output of 6.24 W, wavelength of 890 nm, power density of 34.7 mW/cm2 for 40 min, total energy of 41.6 J/cm2 per knee per session over the knee joints. Heart rate, blood pressure, and knee arterial blood flow velocity were periodically assessed at the baseline, during, and after treatment. Data were analyzed by repeated-measure analysis of covariance. Compared to baseline, there were no statistically significant group x time interaction effects between the 2 groups for heart rate (P=0.160, blood pressure (systolic blood pressure: P=0.861; diastolic blood pressure: P=0.757, or mean arterial blood flow velocity (P=0.769 in follow-up assessments. The present study revealed that although there was no increase of knee arterial blood flow velocity, monochromatic IR therapy produced no detrimental systemic cardiovascular effects.

  7. LIGHT PRESSURE: Theoretical study of the light pressure force acting on a spherical dielectric particle of an arbitrary size in the interference field of two plane monochromatic electromagnetic waves

    Science.gov (United States)

    Guzatov, D. V.; Gaida, L. S.; Afanas'ev, Anatolii A.

    2008-12-01

    The light pressure force acting on a spherical dielectric particle in the interference field of two plane monochromatic electromagnetic waves is studied in detail for different particle radii and angles of incidence of waves.

  8. Acceleration of relativistic electrons due to resonant interaction with oblique monochromatic whistler-mode waves generated in the ionosphere.

    Science.gov (United States)

    Kuzichev, Ilya; Shklyar, David

    2016-04-01

    One of the most challenging problems of the radiation belt studies is the problem of particles energization. Being related to the process of particle precipitation and posing a threat to scientific instruments on satellites, the problem of highly energetic particles in the radiation belts turns out to be very important. A lot of progress has been made in this field, but still some aspects of the energization process remain open. The main mechanism of particle energization in the radiation belts is the resonant interaction with different waves, mainly, in whistler frequency range. The problem of special interest is the resonant wave-particle interaction of the electrons of relativistic energies. Relativistic resonance condition provides some important features such as the so-called relativistic turning acceleration discovered by Omura et al. [1, 2]. This process appears to be a very efficient mechanism of acceleration in the case of interaction with the whistler-mode waves propagating along geomagnetic field lines. But some whistler-mode waves propagate obliquely to the magnetic field lines, and the efficiency of relativistic turning acceleration in this case is to be studied. In this report, we present the Hamiltonian theory of the resonant interaction of relativistic electrons with oblique monochromatic whistler-mode waves. We have shown that the presence of turning point requires a special treatment when one aims to derive the resonant Hamiltonian, and we have obtained two different resonant Hamiltonians: one to be applied far enough from the turning point, while another is valid in the vicinity of the turning point. We have performed numerical simulation of relativistic electron interaction with whistler-mode waves generated in the ionosphere by a monochromatic source. It could be, for example, a low-frequency transmitter. The wave-field distribution along unperturbed particle trajectory is calculated by means of geometrical optics. We show that the obliquity of

  9. A Continuous Millimeter-Wave Imaging Scanner for Art Conservation Science

    Directory of Open Access Journals (Sweden)

    Ayesha Younus

    2011-01-01

    Full Text Available A monochromatic continuous millimeter-wave imaging system coupled with an infrared temperature sensor has been used to investigate artistic objects such as painting artworks or antiquities preserved at the museum of Aquitaine. Especially, 2D and 3D analyses have been performed in order to reveal the internal structure of a nearly 3500-year-old sealed Egyptian jar.

  10. Measuring the amplitude characteristic of an image recorder based on a CCD matrix

    NARCIS (Netherlands)

    Zhurovich, KA; Kirillov, VP; Mikhailov, YA; Sklizkov, GV; Starodub, AN; Sudakov, OA

    2001-01-01

    A method for studying the amplitude characteristic of an image recorder designed on the basis of a charge-coupled device (CCD) matrix is described. The recorder input signal is an intensity of distribution a monochromatic light formed upon Fraunhofer diffraction of the light by two identical slits.

  11. Comprehensive Analysis of Photosynthetic Characteristics and Quality Improvement of Purple Cabbage under Different Combinations of Monochromatic Light

    Science.gov (United States)

    Yang, Biyun; Zhou, Xiangzhu; Xu, Ru; Wang, Jin; Lin, Yizhang; Pang, Jie; Wu, Shuang; Zhong, Fenglin

    2016-01-01

    Light is essential for plant growth. Light intensity, photoperiod, and light quality all affect plant morphology and physiology. Compared to light intensity, photoperiod, little is known about the effects of different monochromatic lights on crop species. To investigate how different lighting conditions influence crops with heterogeneous colors in leaves, we examined photosynthetic characteristics and quality (regarding edibility and nutrition) of purple cabbage under different combinations of lights. Eight different treatments were applied including monochromic red (R), monochromic blue (B), monochromic yellow (Y), monochromic green (G), and the combination of red and blue (3/1, RB), red/blue/yellow (3/1/1, RBY), red/blue/green (3/1/1,RBG), and white light as the control. Our results indicate that RBY (3/1/1) treatment promotes the PSII activity of purple cabbage, resulting in improved light energy utilization. By contrast, both G and Y lights alone have inhibitory effect on the PSII activity of purple cabbage. In addition, RBY (3/1/1) significantly boosts the anthocyanin and flavonoids content compared with other treatments. Although we detected highest soluble protein and vitamin C content under B treatment (increased by 30.0 and 14.3% compared with the control, respectively), RBY (3/1/1) appeared to be the second-best lighting condition (with soluble protein and vitamin C content increased by 8.6 and 4.1%, respectively compared with the control). Thus we prove that the addition of yellow light to the traditional combination of red/blue lighting conditions is beneficial to synthesizing photosynthetic pigments and enables superior outcome of purple cabbage growth. Our results indicate that the growth and nutritional quality of purple cabbage are greatly enhanced under RBY (3/1/1) light, and suggest that strategical management of lighting conditions holds promise in maximizing the economic efficiency of plant production and food quality of vegetables grown in

  12. Effect of melatonin on monochromatic light-induced T-lymphocyte proliferation in the thymus of chickens.

    Science.gov (United States)

    Chen, Fuju; Reheman, Aikebaier; Cao, Jing; Wang, Zixu; Dong, Yulan; Zhang, Yuxian; Chen, Yaoxing

    2016-08-01

    A total of 360 post-hatching day 0 (P0) Arbor Acre male broilers, including intact, sham operation and pinealectomy groups, were exposed to white light (WL), red light (RL), green light (GL) and blue light (BL) from a light-emitting diode (LED) system until for P14. We studied the effects of melatonin and its receptors on monochromatic light-induced T-lymphocyte proliferation in the thymus of broilers. The density of proliferating cell nuclear antigen (PCNA) cells and the proliferation of T-lymphocytes in response to Concanavalin A (ConA) in GL significantly increased both in vivo and in vitro (from 9.57% to 32.03% and from 34.30% to 50.53%, respectively) compared with other lights (plights (p<0.005). However, exogenous melatonin (10(-9)M) significantly increased the proliferative activity of T-lymphocyte by 9.64% (p=0.002). In addition, GL significantly increased mRNA expression levels of Mel1a, Mel1b and Mel1c receptors from 21.09% to 32.57%, and protein expression levels from 24.43% to 42.92% compared with RL (p<0.05). However, these effects were blocked after pinealectomy. Furthermore, 4P-PDOT (a selective Mel1b antagonist) and prazosin (a selective Mel1c antagonist) attenuated GL-induced T-lymphocyte proliferation in response to ConA (p=0.000). Luzindole (a nonselective Mel1a/Mel1b antagonist), however, did not induce these effects (p=0.334). These results suggest that melatonin may mediate GL-induced T-lymphocyte proliferation via the Mel1b and Mel1c receptors but not via the Mel1a receptor.

  13. Impact of different monochromatic LED light colours and bird age on the behavioural output and fear response in ducks

    Directory of Open Access Journals (Sweden)

    Shabiha Sultana

    2013-12-01

    Full Text Available This study was performed to observe the effect of monochromatic light emitting diode (LED light colour and bird age on the behaviour and fear response of ducks. A total of 200 1-day-old ducklings were used in the experiment (two replications, 25 ducklings/pen, and lighting was set up as follows: white (W, control, 400-770 nm, yellow (Y, 600 nm, green (G, 520 nm and blue (B, 460 nm LED lights. Ducks were subjected to 23L: 1D h lighting with 0.1 Watt/m2 light intensity. Video was recorded twice per day (2 h in the morning and 2 h in the afternoon and observed five consecutive days per week. Duration of feeding, drinking, sitting, walking, standing, preening, wing flapping, wing stretching, tail wagging, head shaking, body shaking, ground pecking, peck object, and social interaction behaviour were recorded. At 3 and 6 weeks of age, 10 birds per treatment were subjected to the tonic immobility (TI test (three times/duck. Ducks reared in Y and W light were more active, as expressed by more walking, ground pecking, drinking and social interaction activities than those of ducks under the B light treatment (P<0.05. Ducks showed more time sitting, standing, and preening under B light (P<0.05. Feeding, sitting, standing and drinking behaviours increased, and walking and social interaction behaviours decreased with age of the ducks (P<0.05. Differences in behaviours among different light colours were observed. In addition, the TI test results indicated that B and G light reduced the fear response of the ducks.

  14. Core-shell InGaN/GaN nanowire light emitting diodes analyzed by electron beam induced current microscopy and cathodoluminescence mapping.

    Science.gov (United States)

    Tchernycheva, M; Neplokh, V; Zhang, H; Lavenus, P; Rigutti, L; Bayle, F; Julien, F H; Babichev, A; Jacopin, G; Largeau, L; Ciechonski, R; Vescovi, G; Kryliouk, O

    2015-07-21

    We report on the electron beam induced current (EBIC) microscopy and cathodoluminescence (CL) characterization correlated with compositional analysis of light emitting diodes based on core/shell InGaN/GaN nanowire arrays. The EBIC mapping of cleaved fully operational devices allows to probe the electrical properties of the active region with a nanoscale resolution. In particular, the electrical activity of the p-n junction on the m-planes and on the semi-polar planes of individual nanowires is assessed in top view and cross-sectional geometries. The EBIC maps combined with CL characterization demonstrate the impact of the compositional gradients along the wire axis on the electrical and optical signals: the reduction of the EBIC signal toward the nanowire top is accompanied by an increase of the CL intensity. This effect is interpreted as a consequence of the In and Al gradients in the quantum well and in the electron blocking layer, which influence the carrier extraction efficiency. The interface between the nanowire core and the radially grown layer is shown to produce in some cases a transitory EBIC signal. This observation is explained by the presence of charged traps at this interface, which can be saturated by electron irradiation.

  15. Cathodoluminescence study of Mg activation in non-polar and semi-polar faces of undoped/Mg-doped GaN core-shell nanorods

    Science.gov (United States)

    Hortelano, V.; Martínez, O.; Cuscó, R.; Artús, L.; Jiménez, J.

    2016-03-01

    Spectrally and spatially resolved cathodoluminescence (CL) measurements were carried out at 80 K on undoped/Mg-doped GaN core-shell nanorods grown by selective area growth metalorganic vapor phase epitaxy in order to investigate locally the optical activity of the Mg dopants. A study of the luminescence emission distribution over the different regions of the nanorods is presented. We have investigated the CL fingerprints of the Mg incorporation into the non-polar lateral prismatic facets and the semi-polar facets of the pyramidal tips. The amount of Mg incorporation/activation was varied by using several Mg/Ga flow ratios and post-growth annealing treatment. For lower Mg/Ga flow ratios, the annealed nanorods clearly display a donor-acceptor pair band emission peaking at 3.26-3.27 eV and up to 4 LO phonon replicas, which can be considered as a reliable indicator of effective p-type Mg doping in the nanorod shell. For higher Mg/Ga flow ratios, a substantial enhancement of the yellow luminescence emission as well as several emission subbands are observed, which suggests an increase of disorder and the presence of defects as a consequence of the excess Mg doping.

  16. Correlation between the structural and cathodoluminescence properties in InGaN/GaN multiple quantum wells with large number of quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jing; Zhao, Degang, E-mail: dgzhao@red.semi.ac.cn; Jiang, Desheng; Chen, Ping; Zhu, Jianjun; Liu, Zongshun; Le, Lingcong; He, Xiaoguang; Li, Xiaojing [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, PO BOX 912, Beijing 100083 (China); Wang, Hui; Yang, Hui [Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123 (China); Jahn, Uwe [Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5–7, 10117 Berlin (Germany)

    2014-09-01

    Cathodoluminescence (CL) characteristics on 30-period InGaN/GaN multiple quantum well (MQW) solar cell structures are investigated, revealing the relationship between optical and structural properties of the MQW structures with a large number of quantum wells. In the bottom MQW layers, a blueshift of CL peak along the growth direction is found and attributed to the decrease of indium content due to the compositional pulling effect. An obvious split of emission peak and a redshift of the main emission energy are found in the top MQW layers when the MQW grows above the critical layer thickness. They are attributed to the segregation of In-rich InGaN clusters rather than the increase of indium content in quantum well layer. The MQW structure is identified to consist of two regions: a strained one in the bottom, where the indium content is gradually decreased, and a partly relaxed one in the top with segregated In-rich InGaN clusters.

  17. Upconversion emission and cathodoluminescence of Er{sup 3+}-doped NaYbF{sub 4} nanoparticles for low-temperature thermometry and field emission displays

    Energy Technology Data Exchange (ETDEWEB)

    Du, Peng; Yu, Jae Su [Kyung Hee University, Department of Electronics and Radio Engineering, Yongin (Korea, Republic of); Luo, Laihui [Ningbo University, Department of Microelectronic Science and Engineering, Ningbo (China)

    2017-03-15

    The Er{sup 3+}-doped NaYbF{sub 4} nanoparticles were fabricated by a hydrothermal method. The green and red emissions located at around 525, 542 and 657 nm corresponding to the {sup 2}H{sub 11/2} → {sup 4}I{sub 15/2}, {sup 4}S{sub 3/2} → {sup 4}I{sub 15/2} and {sup 4}F{sub 9/2} → {sup 4}I{sub 15/2} transitions of Er{sup 3+} ions, respectively, were observed when pumped at 980 nm light. Furthermore, with the help of the fluorescence intensity ratio technique, the thermometric properties of as-prepared products from the thermally coupled {sup 2}H{sub 11/2} and {sup 4}S{sub 3/2} levels of Er{sup 3+} ions were studied by analyzing temperature-dependent upconversion (UC) emission spectra. The maximum sensitivity for the Er{sup 3+}-doped NaYbF{sub 4} nanoparticles was found to be around 0.0043 K{sup -} {sup 1} with a temperature range of 93-293 K. In addition, the cathodoluminescence (CL) spectrum of the synthesized nanoparticles was nearly the same as the UC emission spectrum and the CL emission intensity did not exhibit saturation with the increase of accelerating voltage and filament current. (orig.)

  18. Local carrier recombination and associated dynamics in m-plane InGaN/GaN quantum wells probed by picosecond cathodoluminescence

    Science.gov (United States)

    Zhu, Tongtong; Gachet, David; Tang, Fengzai; Fu, Wai Yuen; Oehler, Fabrice; Kappers, Menno J.; Dawson, Phil; Humphreys, Colin J.; Oliver, Rachel A.

    2016-12-01

    We report on spatially resolved and time-resolved cathodoluminescence (CL) studies of the recombination mechanisms of InGaN/GaN quantum wells (QWs) grown by metal-organic vapour phase epitaxy on bulk m-plane Ammono GaN substrates. As a result of the 2° miscut of the GaN substrate, the sample surface exhibits step bunches, where semi-polar QWs with a higher indium concentration than the planar m-plane QWs form during the QW growth. Spatially resolved time-integrated CL maps under both continuous and pulsed excitation show a broad emission band originating from the m-plane QWs and a distinct low energy emission originating from the semi-polar QWs at the step bunches. High resolution time-resolved CL maps reveal that when the m-QWs are excited well away from the step bunches the emission from the m-plane QWs decays with a time constant of 350 ps, whereas the emission originating semi-polar QWs decays with a longer time constant of 489 ps. The time constant of the decay from the semi-polar QWs is longer due to the separation of the carrier wavefunctions caused by the electric field across the semi-polar QWs.

  19. Cathodoluminescence properties of Tb{sup 3+}-doped Na{sub 3}YSi{sub 2}O{sub 7} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Wenyu; Li, Songbo [Innermongolia University of Science and Technology, School of Chemistry and Chemical Engineering, Baotou (China); University of Science and Technology Beijing, School of Metallurgical and Ecological Engineering, Beijing (China); An, Shengli [University of Science and Technology Beijing, School of Metallurgical and Ecological Engineering, Beijing (China); Innermongolia University of Science and Technology, School of Material and Metallurgical Engineering, Baotou (China); Fan, Bin [Innermongolia University of Science and Technology, School of Chemistry and Chemical Engineering, Baotou (China)

    2013-05-15

    Tb{sup 3+}-doped Na{sub 3}YSi{sub 2}O{sub 7} phosphors were prepared by the sol-gel method and then characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy, and cathodoluminescence spectroscopy. The XRD results reveal that the Tb{sup 3+} ions have been introduced as dopants into the Na{sub 3}YSi{sub 2}O{sub 7} host lattice. Under low-voltage electron beam excitation, the phosphors exhibit the characteristic emissions of Tb{sup 3+} ({sup 5} D{sub 3,4}{yields}{sup 7} F{sub J}, J=3-6 transitions). The luminescence color of the phosphors can be tuned from greenish-blue to bluish-green and to green by controlling the Tb {sup 3+} concentration within the 0.0005-0.15 (x value). The optimum Tb {sup 3+} doping concentration is 10 mol%, and the ''dead voltage'' is approximately 1.35 kV. All results indicate that the sample is a phosphor candidate for field-emission displays. (orig.)

  20. Interface properties of Si-SiO{sub 2}-Ta{sub 2}O{sub 5} structure by cathodoluminescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Baraban, A. P.; Dmitriev, V. A.; Drozd, V. E.; Prokofiev, V. A.; Filatova, E. O. [St. Petersburg State University, St. Petersburg 198504 (Russian Federation); Samarin, S. N. [St. Petersburg State University, St. Petersburg 198504 (Russian Federation); School of Physics, The University of Western Australia, Perth, Western Australia 6009 (Australia)

    2016-02-07

    We studied formation of the SiO{sub 2}-T{sub 2}O{sub 5} interface in the Si-SiO{sub 2}-Ta{sub 2}O{sub 5} structure using Cathodoluminescence Spectroscopy (CLS). Analyzing the evolution of CLS spectrum of the Si-SiO{sub 2} structure while depositing the Ta{sub 2}O{sub 5} layer allowed to estimate an optical transmittance of the Ta{sub 2}O{sub 5} layer and its band gap. Spectral features related to the formation of the SiO{sub 2}-Ta{sub 2}O{sub 5} interface were identified by comparison of the experimental CL spectrum of the Si-SiO{sub 2}-Ta{sub 2}O{sub 5} structure and its simulated counterpart. This formation involves a decomposition of silanol groups at the outer surface of the SO{sub 2} layer and creation of the Si{sub x}Ta{sub y}O-type layer containing luminescence centers with the emission band centered at 3 eV photon energy.

  1. Cathodoluminescence spectroscopy of deep defect levels at the ZnSe/GaAs interface with a composition-control interface layer

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, J.; Young, A.P.; Levin, T.M.; Brillson, L.J. [Ohio State Univ., Columbus, OH (United States); Paggel, J.J.; Vanzetti, L. [Lab. Nazionale TASC-INFM, Trieste (Italy); Franciosi, A. [Lab. Nazionale TASC-INFM, Trieste (Italy)]|[Univ. di Trieste (Italy). Dipt. di Fisica]|[Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Science

    1999-07-01

    In this work the authors investigate ZnSe/GaAs heterostructures with an additional 2 nm controlled interfacial layer (CIL) of Se- or Zn-rich composition to modify the band offset. The samples are analyzed as a function of annealing temperature by cathodoluminescence spectroscopy. The as-prepared samples show defect luminescence at {approximately}0.9 eV. With staged annealing at increasing temperatures, both the Zn-rich as well as the Se-rich interfacial layer exhibits luminescence at {approximately}1.9 eV, indicative of defect formation with an onset temperature of {approximately}400 C. Excitation-dependent spectroscopy provides evidence for defect formation near the interface, which extends into the ZnSe epilayer at higher temperatures. Compared to earlier work, where the threshold temperature for defect formation in bulk samples fabricated under Se-rich growth conditions occurs at temperatures as low as 325 C, the resistance to defect formation has now been improved to that of stoichiometric ZnSe. These results demonstrate that epitaxially grown CILs provide a means to alter ZnSe/GaAs band offsets without degrading the heterojunction`s resistance to defect formation at elevated temperatures.

  2. Effect of Size-Dependent Thermal Instability on Synthesis of Zn2 SiO4-SiOx Core–Shell Nanotube Arrays and Their Cathodoluminescence Properties

    Directory of Open Access Journals (Sweden)

    Dierre Benjamin

    2010-01-01

    Full Text Available Abstract Vertically aligned Zn2SiO4-SiOx(x < 2 core–shell nanotube arrays consisting of Zn2SiO4-nanoparticle chains encapsulated into SiOx nanotubes and SiOx-coated Zn2SiO4 coaxial nanotubes were synthesized via one-step thermal annealing process using ZnO nanowire (ZNW arrays as templates. The appearance of different nanotube morphologies was due to size-dependent thermal instability and specific melting of ZNWs. With an increase in ZNW diameter, the formation mechanism changed from decomposition of “etching” to Rayleigh instability and then to Kirkendall effect, consequently resulting in polycrystalline Zn2SiO4-SiOx coaxial nanotubes, single-crystalline Zn2SiO4-nanoparticle-chain-embedded SiOx nanotubes, and single-crystalline Zn2SiO4-SiOx coaxial nanotubes. The difference in spatially resolved optical properties related to a particular morphology was efficiently documented by means of cathodoluminescence (CL spectroscopy using a middle-ultraviolet emission at 310 nm from the Zn2SiO4 phase.

  3. Local Field Enhancement-Induced Enriched Cathodoluminescence Behavior from CuI-RGO Nanophosphor Composite for Field-Emission Display Applications.

    Science.gov (United States)

    Saha, Subhajit; Roy, Rajarshi; Das, Swati; Sen, Dipayan; Ghorai, Uttam Kumar; Mazumder, Nilesh; Chattopadhyay, Kalyan Kumar

    2016-09-28

    Field-emission displays (FEDs) constitute one of the major foci of the cutting edge materials research because of the increasingly escalating demand for high-resolution display panels. However, poor efficiencies of the concurrent low voltage cathodoluminescence (CL) phosphors have created a serious bottleneck in the commercialization of such devices. Herein we report a novel CuI-RGO composite nanophosphor that exhibits bright red emission under low voltage electron beam excitation. Quantitative assessment of CL spectra reveals that CuI-RGO nanocomposite phosphor leads to the 4-fold enhancement in the CL intensity as compared to the pristine CuI counterpart. Addition of RGO in the CuI matrix facilitates efficient triggering of luminescence centers that are activated by local electric field enhancement at the CuI-RGO contact points. In addition, conducting RGO also reduces the negative loading problem on the surface of the nanophosphor composite. The concept presented here opens up a novel generic route for enhancing CL intensity of the existing (nano)phosphors as well as validates the bright prospects of the CuI-RGO composite nanophosphor in this rapidly growing field.

  4. Incoherent imaging in the presence of unwanted laser radiation: vortex and axicon wavefront coding

    Science.gov (United States)

    Watnik, Abbie T.; Ruane, Garreth J.; Swartzlander, Grover A.

    2016-12-01

    Vortex and axicon phase masks are introduced to the pupil plane of an imaging system, altering both the point spread function and optical transfer function for monochromatic and broadband coherent and incoherent light. Each phase mask results in the reduction of the maximum irradiance of a localized coherent laser source, while simultaneously allowing for the recovery of the incoherent background scene. We describe the optical system, image processing, and resulting recovered images obtained through this wavefront encoding approach for laser suppression.

  5. Photon-exposure-dependent photon-stimulated desorption for obtaining photolysis cross section of molecules adsorbed on surface by monochromatic soft x-ray photons.

    Science.gov (United States)

    Chou, L-C; Jang, C-Y; Wu, Y-H; Tsai, W-C; Wang, S-K; Chen, J; Chang, S-C; Liu, C-C; Shai, Y; Wen, C-R

    2008-12-07

    Photon-exposure-dependent positive- and negative-ion photon-stimulated desorption (PSD) was proposed to study the photoreactions and obtain the photolysis cross sections of molecules adsorbed on a single-crystal surface by monochromatic soft x-ray photons with energy near the core level of adsorbate. The changes in the F(+) and F(-) PSD ion yields were measured from CF(3)Cl molecules adsorbed on Si(111)-7x7 at 30 K (CF(3)Cl dose=0.3x10(15) molecules/cm(2), approximately 0.75 monolayer) during irradiation of monochromatic soft x-ray photons near the F(1s) edge. The PSD ion yield data show the following characteristics: (a) The dissociation of adsorbed CF(3)Cl molecules is due to a combination of direct photodissociation via excitation of F(1s) core level and substrate-mediated dissociation [dissociative attachment and dipolar dissociation induced by the photoelectrons emitting from the silicon substrate]. (b) the F(+) ion desorption is associated with the bond breaking of the surface CF(3)Cl, CF(2)Cl, CFCl, and SiF species. (c) the F(-) yield is mainly due to DA and DD of the adsorbed CF(3)Cl molecules. (d) The surface SiF is formed by reaction of the surface Si atom with the neutral fluorine atom, F(+), or F(-) ion produced by scission of C-F bond of CF(3)Cl, CF(2)Cl, or CFCl species. A kinetic model was proposed for the explanation of the photolysis of this submonolayer CF(3)Cl-covered surface. Based on this model and the variation rates of the F(+)F(-) signals during fixed-energy monochromatic photon bombardment at 690.2 and 692.6 eV [near the F(1s) edge], the photolysis cross section was deduced as a function of energy.

  6. Effects of monochromatic light stimuli on the development and Muc2 expression of goblet cells in broiler small intestines during embryogenesis.

    Science.gov (United States)

    Yu, Y; Wang, Z; Cao, J; Dong, Y; Wang, T; Chen, Y

    2014-07-01

    The effects of monochromatic light on the ontogeny, differentiation, and Muc2 expression level in goblet cells were studied in the small intestines of late-stage broiler embryos. The embryos were exposed to blue light (B group), green light (G group), red light (R group), or darkness (D group) throughout the incubation period. On d 15 of incubation (E15), a few acidic goblet cells (only the sulfated subtype) were observed, and Muc2 mRNA expression was detected. On E18, however, neutral, acidic, and intermediate types, as well as the sulfated subtype, were observed in the small intestine, and a decreasing gradient of goblet cell density was found along the duodenum to ileum axis. Up to E21, 3 types of goblet cells and 3 acidic cell subtypes were found in all the small intestines. The goblet cell density increased along the duodenum to ileum axis. Monochromatic light stimulation resulted in no significant differences in the density and types of goblet cells between the different treatment groups on E15 and E18, but an increased Muc2 mRNA expression level was detected on E18 in the G group compared with the other treatment groups. On E21, the goblet cell density, proportion of acidic goblet cells, and Muc2 mRNA expression level increased in the G group compared with other treatment groups. These results suggest that the ontogeny and differentiation of goblet cells in broiler embryos display temporal and spatial differences. Green monochromatic light may have the potential to promote the proliferation and maturation of as well as the expression of Muc2 mRNA in goblet cells of broiler embryos.

  7. Changes of plasma growth hormone, insulin-like growth factors-I, thyroid hormones, and testosterone concentrations in embryos and broiler chickens incubated under monochromatic green light

    Directory of Open Access Journals (Sweden)

    Lin Zhang

    2014-07-01

    Full Text Available Previous studies showed that monochromatic green light stimuli during embryogenesis accelerated posthatch body weight and pectoral muscle growth of broilers. In this experiment, we further investigated whether the regulation of broiler embryonic or posthatch growth by green light stimulus during incubation is associated with the changes of some important hormones at different ages of embryos and broiler chickens. Fertile broiler eggs (Arbor Acres, n=880 were pre-weighed and randomly assigned 1 of 2 incubation treatment groups: i dark condition (control group, and ii monochromatic green light group (560 nm. The monochromatic lighting systems sourced from light-emitting diode lamps were equalised at the intensity of 15 lux (lx at eggshell level. The dark condition was set as a commercial control from day one until hatching. After hatch, 120 day-old male chicks from each group were housed under white light with an intensity of 30 lx at bird-head level. Compared with the dark condition, chicks incubated under the green light showed significantly higher growth hormone (GH levels from 19 d of embryogenesis (E19 to 5 d of posthatch (H5, and higher plasma insulinlike growth factor (IGF-I levels from both E17 to E19 and H3 to H35. No significant differences were found in plasma thyroxine, triiodothyronine, and testosterone in embryos or hatched birds between the 2 groups. These results indicate that somatotropic axis hormones (GH and IGF-I may be the most important contributor to chicken growth promoted by green light stimuli during embryogenesis.

  8. Improved space bandwidth product in image upconversion

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Pedersen, Christian; Tidemand-Lichtenberg, Peter

    2012-01-01

    We present a technique increasing the space bandwidth product of a nonlinear image upconversion process used for spectral imaging. The technique exploits the strong dependency of the phase-matching condition in sum frequency generation (SFG) on the angle of propagation of the interacting fields...... with respect to the optical axis. Appropriate scanning of the phase-match condition (Δk=0) while acquiring images, allow us to perform monochromatic image reconstruction with a significantly increased space bandwidth product. We derive the theory for the image reconstruction process and demonstrate acquisition...... of images with >10 fold increase in space bandwidth product, i.e. the number of pixel elements, when compared to upconversion of images using fixed phase-match conditions....

  9. Monochromatic photography of the Cygnus Loop supernova remnant. Plotting of isophotes of partial nebula radiation in the (OIII) and (NII)+H. cap alpha. lines

    Energy Technology Data Exchange (ETDEWEB)

    Sitnik, T.G.; Toropova, M.S. (Moskovskij Gosudarstvennyj Univ. (USSR). Gosudarstvennyj Astronomicheskij Inst. ' ' GAISh' ' )

    1982-11-01

    System of the isophotes of the 9' size in the west part of the Cyg Loop supernova remnant using monochromatic photographs in the (O3) and (N2)+Hsub(..cap alpha..) lines is obtained. A relative displacement of the regions of emission in these lines is discovered and explained by temperature reduction due to radiative losses behind the shock wave of the supernova explosion. The morphology difference between the (O3) and (N2)+Hsub(..cap alpha..) lines is explained. Anomalously large intensity ratios Isub((O3))/Isub(Hsub(..beta..)) are supposed to be due to spatial separation of the corresponding emission regions.

  10. Photoluminescence and cathodoluminescence properties of Eu{sup 3+} ions activated AMoO{sub 4} (A = Mg, Ca, Sr, Ba) phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Du, Peng; Yu, Jae Su, E-mail: jsyu@khu.ac.kr

    2015-10-15

    Highlights: • Under 393 nm excitation, strong red emission located at 615 nm was observed in all the samples. • The Eu{sup 3+}-activated CaMoO{sub 4} phosphor exhibited the strongest PL properties. • The CIE chromaticity coordinate of Eu{sup 3+}-activated CaMoO{sub 4} phosphor was (0.647,0.352). • The color purity of Eu{sup 3+}-activated CaMoO{sub 4} phosphor was 92.8%. • Strong CL properties were observed in the Eu{sup 3+}-activated CaMoO{sub 4} phosphor. - Abstract: Eu{sup 3+}-activated AMoO{sub 4} (A = Mg, Ca, Sr, Ba) phosphors were synthesized by a solid-state reaction method. Photoluminescence and cathodoluminescence (CL) spectra as well as X-ray diffraction patterns were measured to characterize the fabricated samples. Under 393 nm excitation, strong red emissions located at ∼615 nm corresponding to the {sup 5}D{sub 0} → {sup 7}F{sub 2} transition of Eu{sup 3+} ions were observed in all the samples. Compared with other Eu{sup 3+} ions activated AMoO{sub 4} (A = Mg, Sr, Ba) phosphors, Eu{sup 3+}-activated CaMoO{sub 4} phosphor exhibited the strongest red emission intensity with better Commission Internationale de L’Eclairage chromaticity coordinate and higher color purity. Furthermore, the CL results indicated that the Eu{sup 3+}-activated CaMoO{sub 4} phosphor had excellent luminescence properties.

  11. The Role of Activator-Activator Interactions In Reducing in Low-Voltage-Cathodoluminescence Efficiency in Eu and Tb Doped Phosphors

    Energy Technology Data Exchange (ETDEWEB)

    SEAGER,CARLETON H.; TALLANT,DAVID R.

    1999-12-08

    High resolution measurements of spectrally resolved cathodoluminescence (CL) decay have been made in several commercial and experimental phosphors doped with Eu and Tb at beam energies ranging from 0.8 to 4 keV. CL emission from the lowest two excited states of both rare earth activators was compared to the decay of photoluminescence (PL) after pulsed laser excitation. We find that, at long times after the cessation of electron excitation, the CL decay rates are comparable to those measured in PL, at short times, the decay process is considerably faster and has a noticeable dependence on the energy of the electron beam. These beam energy effects are largest for the higher excited states and for phosphors with larger activator concentrations. Measurements of the experimental phosphors over a range of activator fractions from 0.1 to 0.002 show that the beam energy dependence of the steady-state CL efficiency is larger for higher excited states and weakens as the activator concentration is reduced. The latter effect is strongest for Y{sub 2}SiO{sub 5}:Tb, but also quite evident in Y{sub 2}O{sub 3}:Eu. We suggest that the electron beam dependence of both the decay lifetimes and the steady state CL efficiency may be due to interaction of nearby excited states which occurs as a result of the large energy deposition rate for low energy electrons. This picture-for non-radiative quenching of rare earth emission is an excited state analog of the well-known (ground state-excited state) concentration quenching mechanism.

  12. Comment on "Perspectives of medical X-ray imaging"

    CERN Document Server

    Taibi, A; Tuffanelli, A; Gambaccini, M

    2002-01-01

    In the paper 'Perspectives of medical X-ray imaging' (Nucl. Instr. and Meth. A 466 (2001) 99) the infer, from simple approximations, that the use of HOPG monochromator has no advantage in mammography compared to existing systems. We show that in order to compare imaging properties of different X-ray sources it is necessary to evaluate the spectra after the attenuation of the tissue to be imaged. Indeed, quasi-monochromatic X-ray sources have the potential to enhance image contrast and to reduce patient dose.

  13. Comment on ``Perspectives of medical X-ray imaging''

    Science.gov (United States)

    Taibi, A.; Baldelli, P.; Tuffanelli, A.; Gambaccini, M.

    2002-07-01

    In the paper "Perspectives of medical X-ray imaging" (Nucl. Instr. and Meth. A 466 (2001) 99) the authors infer, from simple approximations, that the use of HOPG monochromator has no advantage in mammography compared to existing systems. We show that in order to compare imaging properties of different X-ray sources it is necessary to evaluate the spectra after the attenuation of the tissue to be imaged. Indeed, quasi-monochromatic X-ray sources have the potential to enhance image contrast and to reduce patient dose.

  14. Utilizing broadband X-rays in a Bragg coherent X-ray diffraction imaging experiment

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Wonsuk; Liu, Wenjun; Harder, Ross; Xu, Ruqing; Fuoss, Paul H.; Hruszkewycz, Stephan O.

    2016-07-26

    A method is presented to simplify Bragg coherent X-ray diffraction imaging studies of complex heterogeneous crystalline materials with a two-stage screening/imaging process that utilizes polychromatic and monochromatic coherent X-rays and is compatible within situsample environments. Coherent white-beam diffraction is used to identify an individual crystal particle or grain that displays desired properties within a larger population. A three-dimensional reciprocal-space map suitable for diffraction imaging is then measured for the Bragg peak of interest using a monochromatic beam energy scan that requires no sample motion, thus simplifyingin situchamber design. This approach was demonstrated with Au nanoparticles and will enable, for example, individual grains in a polycrystalline material of specific orientation to be selected, then imaged in three dimensions while under load.

  15. Utilizing broadband X-rays in a Bragg coherent X-ray diffraction imaging experiment.

    Science.gov (United States)

    Cha, Wonsuk; Liu, Wenjun; Harder, Ross; Xu, Ruqing; Fuoss, Paul H; Hruszkewycz, Stephan O

    2016-09-01

    A method is presented to simplify Bragg coherent X-ray diffraction imaging studies of complex heterogeneous crystalline materials with a two-stage screening/imaging process that utilizes polychromatic and monochromatic coherent X-rays and is compatible with in situ sample environments. Coherent white-beam diffraction is used to identify an individual crystal particle or grain that displays desired properties within a larger population. A three-dimensional reciprocal-space map suitable for diffraction imaging is then measured for the Bragg peak of interest using a monochromatic beam energy scan that requires no sample motion, thus simplifying in situ chamber design. This approach was demonstrated with Au nanoparticles and will enable, for example, individual grains in a polycrystalline material of specific orientation to be selected, then imaged in three dimensions while under load.

  16. Colliding. gamma. e and. gamma gamma. beams based in single-pass e/sup +/e/sup -/ accelerators. Pt. 2. Polarization effects, monochromatization improvement

    Energy Technology Data Exchange (ETDEWEB)

    Ginzburg, I.F.; Kotkin, G.L.; Serbo, V.G.; Panfil, S.L.; Telnov, V.I.

    Polarization effects are considered in colliding ..gamma..e and ..gamma gamma.. beams, which are proposed to be obtained on the basis of linear e/sup +/e/sup -/ colliders (by backward Compton scattering of laser light on electron beams). It is shown that using electrons and laser photons with helicities lambda and Psub(c), such that lambdaPsub(c) < 0, essentially improves the monochromatization. The characteristic laser flash energy, A/sub 0/, which is necessary to obtain a conversion coefficient k proportional 1 with a definite degree of monochromatization, is considerably less (somestimes by one order of magnitude) in the case 2 lambdaPsub(c) = -1 in contrast to the case lambdaPsub(c) = 0. Simultaneously the luminosities Lsub(..gamma..e) and Lsub(..gamma gamma..) essentially increase. Formulae are obtained which allow one to extract the polarization information about ..gamma..e -> X and ..gamma gamma.. -> X reactions. Perculiarities connected with the specific scheme of the ..gamma.. beam preparation are discussed. Problems of the calibration of the ..gamma..e and ..gamma gamma.. collisions for the polarized beams are discussed.

  17. Verification of TG-61 dose for synchrotron-produced monochromatic x-ray beams using fluence-normalized MCNP5 calculations

    CERN Document Server

    Brown, Thomas A D; Alvarez, Diane; Matthews, Kenneth L; Ham, Kyungmin; 10.1118/1.4761870

    2012-01-01

    Ion chamber dosimetry is being used to calibrate dose for cell irradiations designed to investigate photoactivated Auger electron therapy at the Louisiana State University CAMD synchrotron facility. This study performed a dosimetry intercomparison for synchrotron-produced monochromatic x-ray beams at 25 and 35 keV. Ion chamber depth-dose measurements in a PMMA phantom were compared with the product of MCNP5 Monte Carlo calculations of dose per fluence and measured incident fluence. Monochromatic beams of 25 and 35 keV were generated on the tomography beamline at CAMD. A cylindrical, air-equivalent ion chamber was used to measure the ionization created in a 10x10x10-cm3 PMMA phantom for depths from 0.6 to 7.7 cm. The American Association of Physicists in Medicine TG-61 protocol was applied to convert measured ionization into dose. Photon fluence was determined using a NaI detector to make scattering measurements of the beam from a thin polyethylene target at angles 30 degrees to 60 degrees. Differential Compto...

  18. Perspective of monochromatic gamma-ray line detection with the High Energy cosmic-Radiation Detection (HERD) facility onboard China's Space Station

    CERN Document Server

    Huang, Xiaoyuan; Tsai, Yue-Lin Sming; Xu, Ming; Yuan, Qiang; Chang, Jin; Dong, Yong-Wei; Hu, Bing-Liang; Lü, Jun-Guang; Wang, Le; Wu, Bo-Bing; Zhang, Shuang-Nan

    2015-01-01

    HERD is the High Energy cosmic-Radiation Detection instrument proposed to operate onboard China's space station in the 2020s. It is designed to detect energetic cosmic ray nuclei, leptons and photons with a high energy resolution ($\\sim1\\%$ for electrons and photons and $20\\%$ for nuclei) and a large geometry factor ($>3\\, m^2sr$ for electrons and diffuse photons and $>2\\, m^2sr$ for nuclei). In this work we discuss the capability of HERD to detect monochromatic $\\gamma$-ray lines, based on simulations of the detector performance. It is shown that HERD will be one of the most sensitive instruments for monochromatic $\\gamma$-ray searches at energies between $\\sim10$ to a few hundred GeV. Above hundreds of GeV, Cherenkov telescopes will be more sensitive due to their large effective area. As a specific example, we show that a good portion of the parameter space of a supersymmetric dark matter model can be probed with HERD.

  19. Perspective of monochromatic gamma-ray line detection with the High Energy cosmic-Radiation Detection (HERD) facility onboard China's space station

    Science.gov (United States)

    Huang, Xiaoyuan; Lamperstorfer, Anna S.; Tsai, Yue-Lin Sming; Xu, Ming; Yuan, Qiang; Chang, Jin; Dong, Yong-Wei; Hu, Bing-Liang; Lü, Jun-Guang; Wang, Le; Wu, Bo-Bing; Zhang, Shuang-Nan

    2016-05-01

    HERD is the High Energy cosmic-Radiation Detection instrument proposed to operate onboard China's space station in the 2020s. It is designed to detect energetic cosmic ray nuclei, leptons and photons with a high energy resolution (∼1% for electrons and photons and 20% for nuclei) and a large geometry factor (>3 m2 sr for electrons and diffuse photons and > [2]m2 sr for nuclei). In this work we discuss the capability of HERD to detect monochromatic γ-ray lines, based on simulations of the detector performance. It is shown that HERD will be one of the most sensitive instruments for monochromatic γ-ray searches at energies between ∼ 10 to a few hundred GeV. Above hundreds of GeV, Cherenkov telescopes will be more sensitive due to their large effective area. As a specific example, we show that a good portion of the parameter space of a supersymmetric dark matter model can be probed with HERD.

  20. Dose-response curve of EBT, EBT2, and EBT3 radiochromic films to synchrotron-produced monochromatic x-ray beams

    CERN Document Server

    Brown, Thomas A D; Alvarez, Diane; Matthews, Kenneth L; Ham, Kyungmin; Dugas, Joseph P; 10.1118/1.4767770

    2012-01-01

    This work investigates the dose-response curves of GAFCHROMIC EBT, EBT2, and EBT3 radiochromic films using synchrotron-produced monochromatic x-ray beams. EBT2 film is being utilized for dose verification in photoactivated Auger electron therapy at the Louisiana State University CAMD synchrotron facility. Monochromatic beams of 25, 30, and 35 keV were generated on the tomography beamline at CAMD. Ion chamber depth-dose measurements were used to determine the dose delivered to films irradiated at depths from 0.7 to 8.5 cm in a 10x10x10-cm3 PMMA phantom. AAPM TG-61 protocol was applied to convert measured ionization into dose. Films were digitized using an Epson 1680 Professional flatbed scanner and analyzed using the net optical density (NOD) derived from the red channel. A dose-response curve was obtained at 35 keV for EBT film, and at 25, 30, and 35 keV for EBT2 and EBT3 films. Calibrations of films for 4 MV x-rays were obtained for comparison using a radiotherapy accelerator at Mary Bird Perkins Cancer Cent...

  1. Characterization of four-color multi-package white light-emitting diodes combined with various green monochromatic phosphor-converted light-emitting diodes

    Science.gov (United States)

    Oh, Ji Hye; Lee, Keyong Nam; Do, Young Rag

    2012-03-01

    In this study, several combinations of multi-package white light-emitting diodes (LEDs), which combine an InGaN blue LED with green, amber, and red phosphor-converted LEDs (pc-LEDs), were characterized by changing the peak wavelength of green pc-LEDs between 515nm and 560nm (515, 521, 530, 540, 550, 560nm) in color temperature of 6,500K and 3,500K. Various green monochromatic pc-LEDs were fabricated by capping a long-wave pass-filter (LWPF) on top of pc-LEDs to improve luminous efficacy and color purity. LWPF-capped green monochromatic pc-LED can address the drawback of green semiconductor-type III-V LED, such as low luminous efficacy in the region of green gap wavelength. Luminous efficacy and color rendering index (CRI) of multi-package white LEDs are compared with changing the driving current of individual LED in various multi-package white LEDs. This study provides a best combination of four-color multi-package white LEDs which has high luminous efficacy and good CRI.

  2. A noise-optimized virtual monochromatic reconstruction algorithm improves stent visualization and diagnostic accuracy for detection of in-stent re-stenosis in lower extremity run-off CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Mangold, Stefanie [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); De Cecco, Carlo N.; Yamada, Ricardo T.; Varga-Szemes, Akos; Stubenrauch, Andrew C.; Fuller, Stephen R. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Schoepf, U.J. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Caruso, Damiano [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' , Department of Radiological Sciences, Oncology and Pathology, Rome (Italy); Vogl, Thomas J.; Wichmann, Julian L. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); University Hospital Frankfurt, Department of Diagnostic and Interventional Radiology, Frankfurt (Germany); Nikolaou, Konstantin [Eberhard-Karls University Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Todoran, Thomas M. [Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States)

    2016-12-15

    To evaluate the impact of noise-optimized virtual monochromatic imaging (VMI+) on stent visualization and accuracy for in-stent re-stenosis at lower extremity dual-energy CT angiography (DE-CTA). We evaluated third-generation dual-source DE-CTA studies in 31 patients with prior stent placement. Images were reconstructed with linear blending (F{sub 0}.5) and VMI+ at 40-150 keV. In-stent luminal diameter was measured and contrast-to-noise ratio (CNR) calculated. Diagnostic confidence was determined using a five-point scale. In 21 patients with invasive catheter angiography, accuracy for significant re-stenosis (≥50 %) was assessed at F{sub 0}.5 and 80 keV-VMI+ chosen as the optimal energy level based on image-quality analysis. At CTA, 45 stents were present. DSA was available for 28 stents whereas 12 stents showed significant re-stenosis. CNR was significantly higher with ≤80 keV-VMI+ (17.9 ± 6.4-33.7 ± 12.3) compared to F{sub 0}.5 (16.9 ± 4.8; all p < 0.0463); luminal stent diameters were increased at ≥70 keV (5.41 ± 1.8-5.92 ± 1.7 vs. 5.27 ± 1.8, all p < 0.001) and diagnostic confidence was highest at 70-80 keV-VMI+ (4.90 ± 0.48-4.88 ± 0.63 vs. 4.60 ± 0.66, p = 0.001, 0.0042). Sensitivity, negative predictive value and accuracy for re-stenosis were higher with 80 keV-VMI+ (100, 100, 96.4 %) than F{sub 0}.5 (90.9, 94.1, 89.3 %). 80 keV-VMI+ improves image quality, diagnostic confidence and accuracy for stent evaluation at lower extremity DE-CTA. (orig.)

  3. Prior image constrained image reconstruction in emerging computed tomography applications

    Science.gov (United States)

    Brunner, Stephen T.

    Advances have been made in computed tomography (CT), especially in the past five years, by incorporating prior images into the image reconstruction process. In this dissertation, we investigate prior image constrained image reconstruction in three emerging CT applications: dual-energy CT, multi-energy photon-counting CT, and cone-beam CT in image-guided radiation therapy. First, we investigate the application of Prior Image Constrained Compressed Sensing (PICCS) in dual-energy CT, which has been called "one of the hottest research areas in CT." Phantom and animal studies are conducted using a state-of-the-art 64-slice GE Discovery 750 HD CT scanner to investigate the extent to which PICCS can enable radiation dose reduction in material density and virtual monochromatic imaging. Second, we extend the application of PICCS from dual-energy CT to multi-energy photon-counting CT, which has been called "one of the 12 topics in CT to be critical in the next decade." Numerical simulations are conducted to generate multiple energy bin images for a photon-counting CT acquisition and to investigate the extent to which PICCS can enable radiation dose efficiency improvement. Third, we investigate the performance of a newly proposed prior image constrained scatter correction technique to correct scatter-induced shading artifacts in cone-beam CT, which, when used in image-guided radiation therapy procedures, can assist in patient localization, and potentially, dose verification and adaptive radiation therapy. Phantom studies are conducted using a Varian 2100 EX system with an on-board imager to investigate the extent to which the prior image constrained scatter correction technique can mitigate scatter-induced shading artifacts in cone-beam CT. Results show that these prior image constrained image reconstruction techniques can reduce radiation dose in dual-energy CT by 50% in phantom and animal studies in material density and virtual monochromatic imaging, can lead to radiation

  4. Enhanced production of reactive oxygen species by gadolinium oxide nanoparticles under core-inner-shell excitation by proton or monochromatic X-ray irradiation: implication of the contribution from the interatomic de-excitation-mediated nanoradiator effect to dose enhancement.

    Science.gov (United States)

    Seo, Seung-Jun; Han, Sung-Mi; Cho, Jae-Hoon; Hyodo, Kazuyuki; Zaboronok, Alexander; You, He; Peach, Ken; Hill, Mark A; Kim, Jong-Ki

    2015-11-01

    Core-inner-valence ionization of high-Z nanoparticle atomic clusters can de-excite electrons through various interatomic de-excitation processes, thereby leading to the ionization of both directly exposed atoms and adjacent neutral atoms within the nanoparticles, and to an enhancement in photon-electron emission, which is termed the nanoradiator effect. To investigate the nanoradiator-mediated dose enhancement in the radio-sensitizing of high-Z nanoparticles, the production of reactive oxygen species (ROS) was measured in a gadolinium oxide nanoparticle (Gd-oxide NP) solution under core-inner-valence excitation of Gd with either 50 keV monochromatic synchrotron X-rays or 45 MeV protons. This measurement was compared with either a radiation-only control or a gadolinium-chelate magnetic resonance imaging contrast agent solution containing equal amounts of gadolinium as the separate atomic species in which Gd-Gd interatomic de-excitations are absent. Ionization excitations followed by ROS measurements were performed on nanoparticle-loaded cells or aqueous solutions. Both photoexcitation and proton impact produced a dose-dependent enhancement in the production of ROS by a range of factors from 1.6 to 1.94 compared with the radiation-only control. Enhanced production of ROS, by a factor of 1.83, was observed from Gd-oxide NP atomic clusters compared with the Gd-chelate molecule, with a Gd concentration of 48 μg/mL in the core-level photon excitation, or by a factor of 1.82 under a Gd concentration of 12 μg/mL for the proton impact at 10 Gy (p < 0.02). The enhanced production of ROS in the irradiated nanoparticles suggests the potential for additional therapeutic dose enhancements in radiation treatment via the potent Gd-Gd interatomic de-excitation-driven nanoradiator effect.

  5. Depth of interaction and bias voltage depenence of the spectral response in a pixellated CdTe detector operating in time-over-threshold mode subjected to monochromatic X-rays

    Science.gov (United States)

    Fröjdh, E.; Fröjdh, C.; Gimenez, E. N.; Maneuski, D.; Marchal, J.; Norlin, B.; O'Shea, V.; Stewart, G.; Wilhelm, H.; Modh Zain, R.; Thungström, G.

    2012-03-01

    High stopping power is one of the most important figures of merit for X-ray detectors. CdTe is a promising material but suffers from: material defects, non-ideal charge transport and long range X-ray fluorescence. Those factors reduce the image quality and deteriorate spectral information. In this project we used a monochromatic pencil beam collimated through a 20μm pinhole to measure the detector spectral response in dependance on the depth of interaction. The sensor was a 1mm thick CdTe detector with a pixel pitch of 110μm, bump bonded to a Timepix readout chip operating in Time-Over-Threshold mode. The measurements were carried out at the Extreme Conditions beamline I15 of the Diamond Light Source. The beam was entering the sensor at an angle of \\texttildelow20 degrees to the surface and then passed through \\texttildelow25 pixels before leaving through the bottom of the sensor. The photon energy was tuned to 77keV giving a variation in the beam intensity of about three orders of magnitude along the beam path. Spectra in Time-over-Threshold (ToT) mode were recorded showing each individual interaction. The bias voltage was varied between -30V and -300V to investigate how the electric field affected the spectral information. For this setup it is worth noticing the large impact of fluorescence. At -300V the photo peak and escape peak are of similar height. For high bias voltages the spectra remains clear throughout the whole depth but for lower voltages as -50V, only the bottom part of the sensor carries spectral information. This is an effect of the low hole mobility and the longer range the electrons have to travel in a low field.

  6. Dose-response curve of EBT, EBT2, and EBT3 radiochromic films to synchrotron-produced monochromatic x-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Thomas A. D.; Hogstrom, Kenneth R.; Alvarez, Diane; Matthews, Kenneth L. II; Ham, Kyungmin; Dugas, Joseph P. [Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809 and Department of Physics and Astronomy, Louisiana State University and A and M College, 202 Nicholson Hall, Baton Rouge, Louisiana 70803 (United States); Department of Physics and Astronomy, Louisiana State University and A and M College, 202 Nicholson Hall, Baton Rouge, Louisiana 70803 (United States); Center for Advanced Microstructures and Devices, Louisiana State University and A and M College, 6980 Jefferson Highway, Baton Rouge, Louisiana 70806 (United States); Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, Louisiana 70809 and Department of Physics and Astronomy, Louisiana State University and A and M College, 202 Nicholson Hall, Baton Rouge, Louisiana 70803 (United States)

    2012-12-15

    Purpose: This work investigates the dose-response curves of GAFCHROMIC{sup Registered-Sign} EBT, EBT2, and EBT3 radiochromic films using synchrotron-produced monochromatic x-ray beams. EBT2 film is being utilized for dose verification in photoactivated Auger electron therapy at the Louisiana State University Center for Advanced Microstructures and Devices (CAMD) synchrotron facility. Methods: Monochromatic beams of 25, 30, and 35 keV were generated on the tomography beamline at CAMD. Ion chamber depth-dose measurements were used to determine the dose delivered to films irradiated at depths from 0.7 to 8.5 cm in a 10 Multiplication-Sign 10 Multiplication-Sign 10-cm{sup 3} polymethylmethacrylate phantom. AAPM TG-61 protocol was applied to convert measured ionization into dose. Films were digitized using an Epson 1680 Professional flatbed scanner and analyzed using the net optical density (NOD) derived from the red channel. A dose-response curve was obtained at 35 keV for EBT film, and at 25, 30, and 35 keV for EBT2 and EBT3 films. Calibrations of films for 4 MV x-rays were obtained for comparison using a radiotherapy accelerator at Mary Bird Perkins Cancer Center. Results: The sensitivity (NOD per unit dose) of EBT film at 35 keV relative to that for 4-MV x-rays was 0.73 and 0.76 for doses 50 and 100 cGy, respectively. The sensitivity of EBT2 film at 25, 30, and 35 keV relative to that for 4-MV x-rays varied from 1.09-1.07, 1.23-1.17, and 1.27-1.19 for doses 50-200 cGy, respectively. For EBT3 film the relative sensitivity was within 3% of unity for all three monochromatic x-ray beams. Conclusions: EBT and EBT2 film sensitivity showed strong energy dependence over an energy range of 25 keV-4 MV, although this dependence becomes weaker for larger doses. EBT3 film shows weak energy dependence, indicating that it would be a better dosimeter for kV x-ray beams where beam hardening effects can result in large changes in the effective energy.

  7. Perspectives of medical X-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Freudenberger, J. E-mail: joerg.freudenberger@med.siemens.de; Hell, E.; Knuepfer, W

    2001-06-21

    While X-ray image intensifiers (XII), storage phosphor screens and film-screen systems are still the work horses of medical imaging, large flat panel solid state detectors using either scintillators and amorphous silicon photo diode arrays (FD-Si), or direct X-ray conversion in amorphous selenium are reaching maturity. The main advantage with respect to image quality and low patient dose of the XII and FD-Si systems is caused by the rise of the Detector Quantum Efficiency originating from the application of thick needle-structured phosphor X-ray absorbers. With the detectors getting closer to an optimal state, further progress in medical X-ray imaging requires an improvement of the usable source characteristics. The development of clinical monochromatic X-ray sources of high power would not only allow an improved contrast-to-dose ratio by allowing smaller average photon energies in applications but would also lead to new imaging techniques.

  8. Perspectives of medical X-ray imaging

    Science.gov (United States)

    Freudenberger, J.; Hell, E.; Knüpfer, W.

    2001-06-01

    While X-ray image intensifiers (XII), storage phosphor screens and film-screen systems are still the work horses of medical imaging, large flat panel solid state detectors using either scintillators and amorphous silicon photo diode arrays (FD-Si), or direct X-ray conversion in amorphous selenium are reaching maturity. The main advantage with respect to image quality and low patient dose of the XII and FD-Si systems is caused by the rise of the Detector Quantum Efficiency originating from the application of thick needle-structured phosphor X-ray absorbers. With the detectors getting closer to an optimal state, further progress in medical X-ray imaging requires an improvement of the usable source characteristics. The development of clinical monochromatic X-ray sources of high power would not only allow an improved contrast-to-dose ratio by allowing smaller average photon energies in applications but would also lead to new imaging techniques.

  9. EEG based image encryption via quantum walks.

    Science.gov (United States)

    Rawat, N; Shin, Y; Balasingham, I

    2016-08-01

    An electroencephalogram (EEG) based image encryption combined with Quantum walks (QW) is encoded in Fresnel domain. The computational version of EEG randomizes the original plaintext whereas QW can serve as an excellent key generator due to its inherent nonlinear chaotic dynamic behavior. First, a spatially coherent monochromatic laser beam passes through an SLM, which introduces an arbitrary EEG phase-only mask. The modified beam is collected by a CCD. Further, the intensity is multiply with the QW digitally. EEG shows high sensitivity to system parameters and capable of encrypting and transmitting the data whereas QW has unpredictability, stability and non-periodicity. Only applying the correct keys, the original image can be retrieved successfully. Simulations and comparisons show the proposed method to be secure enough for image encryption and outperforms prior works. The proposed method opens the door towards introducing EEG and quantum computation into image encryption and promotes the convergence between our approach and image processing.

  10. Monochromatic excimer light versus combination of topical steroid with vitamin D3 analogue in the treatment of nonsegmental vitiligo: a randomized blinded comparative study.

    Science.gov (United States)

    Abdel Latif, Azmy Ahmed; Ibrahim, Shady Mahmoud Attia

    2015-01-01

    Vitiligo is a difficult disease to treat, socially stigmatizing its patients. Monochromatic excimer light (MEL) was developed for use in dermatology and adapted for the treatment of vitiligo. Comparing the efficacy of MEL versus topical combination therapy of vitamin D3 analogue and steroid in the treatment of nonsegmental vitiligo. Forty-four patients with localized and stable nonsegmental vitiligo participated in the present study. In each patient, two lesions were selected and divided randomly into two groups, group A was treated with daily topical combination of calcipotriol and betamethasone and group B was treated with biweekly sessions of MEL for 3 months. Efficacy based on repigmentation percentages were blindly evaluated by two independent physicians and patient's satisfaction. There was significant improvement in both treatment modalities at the end of the study, but without significant differences in both groups. There was a significant difference between both groups regarding the onset of repigmentation (p-value vitiligo.

  11. A possibility of parallel and anti-parallel diffraction measurements on neutron diffractometer employing bent perfect crystal monochromator at the monochromatic focusing condition

    Indian Academy of Sciences (India)

    Yong Nam Choi; Shin Ae Kim; Sung Kyu Kim; Sung Baek Kim; Chang-Hee Lee; Pivel Mikula

    2004-07-01

    In a conventional diffractometer having single monochromator, only one position, parallel position, is used for the diffraction experiment (i.e. detection) because the resolution property of the other one, anti-parallel position, is very poor. However, a bent perfect crystal (BPC) monochromator at monochromatic focusing condition can provide a quite flat and equal resolution property at both parallel and anti-parallel positions and thus one can have a chance to use both sides for the diffraction experiment. From the data of the FWHM and the / measured on three diffraction geometries (symmetric, asymmetric compression and asymmetric expansion), we can conclude that the simultaneous diffraction measurement in both parallel and anti-parallel positions can be achieved.

  12. QED-based Optical Bloch Equations without electric dipole approximation: A model for a two-level atom interacting with a monochromatic X-ray laser beam

    CERN Document Server

    Zhang, Wen-Zhuo

    2012-01-01

    We derive a set of optical Bloch equations (OBEs) directly from the minimal-coupling Hamiltonian density of the bound-state quantum electrodynamics (bound-state QED). Such optical Bloch equations are beyond the former widely-used ones due to that there is no electric dipole approximation (EDA) on the minimal-coupling Hamiltonian density of the bound-state QED. Then our optical Bloch equations can describe a two-level atom interacting with a monochromatic light of arbitrary wavelength, which are suitable to study the spectroscopy and the Rabi oscillations of two-level atoms in X-ray laser beams since that the wavelength of X-ray is close to an atom to make the electric dipole approximation (EDA) invalid.

  13. Characteristics of a multi-keV monochromatic point x-ray source based on vacuum diode with laser-produced plasma as cathode

    Indian Academy of Sciences (India)

    A Moorti; A Raghuramaiah; P A Naik; P D Gupta

    2004-11-01

    Temporal, spatial and spectral characteristics of a multi-keV monochromatic point x-ray source based on vacuum diode with laser-produced plasma as cathode are presented. Electrons from a laser-produced aluminium plasma were accelerated towards a conical point tip titanium anode to generate K-shell x-ray radiation. Approximately 1010 photons/pulse were generated in x-ray pulses of ∼ 18 to ∼ 28 ns duration from a source of ∼ 300 m diameter, at ℎ = 4.51 keV ( emission of titanium), with a brightness of ∼ 1020 photons/cm2 /s/sr. This was sufficient to record single-shot x-ray radiographs of physical objects on a DEF-5 x-ray film kept at a distance of up to ∼ 10 cm.

  14. Inactivation and potential reactivation of pathogenic Escherichia coli O157:H7 in apple juice following ultraviolet light exposure at three monochromatic wavelengths.

    Science.gov (United States)

    Yin, Fugui; Zhu, Yan; Koutchma, Tatiana; Gong, Joshua

    2015-04-01

    Ultraviolet (UV) light irradiation at 254 nm is considered as a novel non-thermal method for decontamination of foodborne pathogenic bacteria. However, lower penetration depth of UV light at 254 nm in apple juice resulted in higher UV dose consumption during apple juice decontamination. In addition, no studies are available on the reactivation of pathogens following exposure to UV light in drinks and beverages. Two novel monochromatic UV light sources (λ = 222 and 282 nm) have been developed for bacterial disinfection. However, the inactivation of pathogenic Escherichia coli O157:H7 following exposure to these UV wavelengths is still unclear. Therefore, the present study was conducted to determine the inactivation and reactivation potential of pathogenic E. coli O157:H7 in apple juice following exposure to UV light at three monochromatic wavelengths: Far UV (λ = 222 nm), Far UV+ (λ = 282 nm) and UVC light (λ = 254 nm). The results showed that E. coli O157:H7 is acid-resistant, and up to 99.50% of cells survived in apple juice when incubated at 20 °C for 24 h. Inactivation of E. coli O157:H7 following exposure to Far UV light (2.81 Log reduction) was higher (P exposure to UV light as determined by the regular plating method. In addition, the exposure to Far UV light at 222 nm followed by incubating at 37 °C significantly decreased (P < 0.05) the survival of E. coli O157:H7 during dark incubation phase compared to that of UVC and Far UV+ light.

  15. Cathodoluminescence of Irradiated Hafnium Dioxide

    Science.gov (United States)

    2011-03-01

    with the findings Ito et al. Mendoza et al., 2010, studied HfO2 films deposited by ultrasonic spray pyrolysis process on corning glass substrates at...examined were grown by either atomic layer deposition (ALD) or pulsed laser deposition (PLD); the PLD samples were deposited on substrates maintained at...varying temperatures during deposition (300°C, 500°C, and 750°C), the AQLD samples on substrates at 250°C. It was found that the ALD samples had a much

  16. Nanoscale imaging using a compact laser plasma EUV source

    Science.gov (United States)

    Wachulak, Przemyslaw; Bartnik, Andrzej; Fiedorowicz, Henryk; Kostecki, Jerzy; Jarocki, Roman; Szczurek, Miroslaw; Szczurek, Anna; Feigl, Torsten; Pina, Ladislav

    2012-05-01

    High resolution imaging methods and techniques are currently under development. One of them is an extreme ultraviolet (EUV) microscopy, based on Fresnel zone plates. In this paper a compact, high-repetition, laser-plasma EUV source, emitting quasi-monochromatic radiation at 13.8nm wavelength was used in a desktop EUV transmission microscopy with a spatial (half-pitch) resolution of 50nm. EUV microscopy images of objects with various thicknesses and the spatial resolution measurements using the knife-edge test are presented.

  17. Fluorescence polarization imaging for delineating nonmelanoma skin cancers

    Science.gov (United States)

    Yaroslavsky, A. N.; Neel, V.; Anderson, R. R.

    2004-09-01

    We present a method for detecting nonmelanoma skin cancers using exogenous fluorescence polarization. We built an automated system that permits exogenous fluorescence polarization imaging. It includes a tunable linearly polarized monochromatic light source and a CCD camera equipped with a rotating linear polarizer and a filter to reject excitation light. Two fluorophores that are retained in tumors, toluidine blue and methylene blue, are employed. We demonstrate that fluorescence polarization imaging can be used for accurate delineation of nonmelanoma cancers. The results suggest that this optical technique may be suitable for real-time noninvasive demarcation of epithelial cancers.

  18. Comment on 'Perspectives of medical X-ray imaging'

    Energy Technology Data Exchange (ETDEWEB)

    Taibi, A. E-mail: taibi@fe.infn.it; Baldelli, P.; Tuffanelli, A.; Gambaccini, M

    2002-07-21

    In the paper 'Perspectives of medical X-ray imaging' (Nucl. Instr. and Meth. A 466 (2001) 99) the authors infer, from simple approximations, that the use of HOPG monochromator has no advantage in mammography compared to existing systems. We show that in order to compare imaging properties of different X-ray sources it is necessary to evaluate the spectra after the attenuation of the tissue to be imaged. Indeed, quasi-monochromatic X-ray sources have the potential to enhance image contrast and to reduce patient dose.

  19. High Frequency Active Auroral Research Program (HAARP) imager. Final report, 29 August 1991-29 August 1993

    Energy Technology Data Exchange (ETDEWEB)

    Lance, C.; Eather, R.

    1993-09-30

    A low-light-level monochromatic imaging system was designed and fabricated which was optimized to detect and record optical emissions associated with high-power rf heating of the ionosphere. The instrument is capable of detecting very low intensities, of the order of 1 Rayleigh, from typical ionospheric atomic and molecular emissions. This is achieved through co-adding of ON images during heater pulses and subtraction of OFF (background) images between pulses. Images can be displayed and analyzed in real time and stored in optical disc for later analysis. Full image processing software is provided which was customized for this application and uses menu or mouse user interaction.

  20. Monochromatic excimer light (308 nm) for the treatment of skin diseases%308 nm准分子光治疗皮肤病进展

    Institute of Scientific and Technical Information of China (English)

    丛林; 杨蓉娅

    2015-01-01

    308 nm准分子光是一种单频中波紫外光,为治疗白癜风的首选疗法之一.308 nm准分子光和308 nm准分子激光治疗白癜风的疗效无明显差异.研究表明,308 nm准分子光还可作为银屑病、掌跖脓疱病、斑秃等慢性皮肤病新的治疗选择.目前已有308 nm准分子光治疗无色素痣、蕈样肉芽肿、CD30+淋巴瘤样丘疹病、硬化性苔癣、结节性痒疹、局限性硬皮病、环状肉芽肿及浆细胞唇炎的个案报道,与传统光疗相比,308 nm准分子光累积照射剂量少,发生皮肤癌的风险极低,其不良反应主要为暂时性红斑.308 nm准分子光的治疗机制尚不明确.%As a kind of monochromatic ultraviolet B,308-nm monochromatic excimer light (MEL) is one of the first choice treatments for vitiligo.There is no significant difference in the therapeutic effect on vitiligo between 308-nm MEL and 308-nm excimer laser.Recent studies have shown that 308-nm MEL can also serve as the treatment of choice for some other chronic skin diseases,such as psoriasis,palmoplantaris pustulosis and alopecia areata.Furthermore,there have been case reports on the use of 308-nm MEL for the treatment of achromic naevus,mycosis fungoides,CD30+ lymphomatoid papulosis,lichen sclerosus,prurigo nodularis,localized scleroderma,granuloma annulare and plasma cell cheilitis.Compared with conventional phototherapy,308-nm MEL has the advantages of less cumulative radiation dose and lower risks of skin cancers.The main adverse reaction to 308-nm MEL is transient erythema.The therapeutic mechanism of 308-nm MEL is still unclear.

  1. High-Resolution Large-Field-of-View Ultrasound Breast Imager

    Science.gov (United States)

    2013-06-01

    The views, opinions and/or findings contained in this report are those of the author(s) and should not be construed as...Projection images can be acquired at multiple transducer frequencies with several monochromatic sources. Assuming normal breast parenchyma containing ...three point mount • Attach support to mirror back • Use mirror with toroid and comatic shape Secondary mirror: • Needs to be able to tilt in

  2. Photosynthesis-dependent and -independent responses of stomata to blue, red and green monochromatic light: differences between the normally oriented and inverted leaves of sunflower.

    Science.gov (United States)

    Wang, Yin; Noguchi, Ko; Terashima, Ichiro

    2011-03-01

    The effects of growth light environment on stomatal light responses were analyzed. We inverted leaves of sunflower (Helianthus annuus) for 2 weeks until their full expansion, and measured gas exchange properties of the adaxial and abaxial sides separately. The sensitivity to light assessed as the increase in stomatal conductance was generally higher in the abaxial stomata than in the adaxial stomata, and these differences could not be completely changed by the inversion treatment. We also treated the leaves with DCMU to inhibit photosynthesis and evaluated the photosynthesis-dependent and -independent components of stomatal light responses. The red light response of stomata in both normally oriented and inverted leaves relied only on the photosynthesis-dependent component. The blue light response involved both the photosynthesis-dependent and photosynthesis-independent components, and the relative contributions of the two components differed between the normally oriented and inverted leaves. A green light response was observed only in the abaxial stomata, which also involved the photosynthesis-dependent and photosynthesis-independent components, strongly suggesting the existence of a green light receptor in sunflower leaves. Moreover, acclimation of the abaxial stomata to strong direct light eliminated the photosynthesis-independent component in the green light response. The results showed that stomatal responses to monochromatic light change considerably in response to growth light environment, although some of these responses appear to be determined inherently. © The Author 2011. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.

  3. Spectral responsivity calibration of the reference radiation thermometer at KRISS by using a super-continuum laser-based high-accuracy monochromatic source

    Science.gov (United States)

    Yoo, Yong Shim; Kim, Gun Jung; Park, Seongchong; Lee, Dong-Hoon; Kim, Bong-Hak

    2016-12-01

    We report on the calibration of the relative spectral responsivity of the reference radiation thermometer, model LP4, which is used for the experimental realisation of the international temperature scale of 1990 above 960 °C at the Korea Research Institute of Standards and Science. The relative spectral responsivity of LP4 is measured by using a monochromatic source consisting of a super-continuum laser and a double-grating monochromator. By monitoring the wavelength of the output beam directly with a calibrated wavelength-meter, we achieved a high-accuracy measurement of spectral responsivity with a maximum wavelength error of less than 3 pm, a narrow spectral bandwidth of less than 0.4 nm, and a high dynamic range over 8 decades. We evaluated the contributions of various uncertainty components of the spectral responsivity measurement to the uncertainty of the temperature scale based on a practical estimation approach, which numerically calculates the maximal effects of the variations of each component. As a result, we evaluate the uncertainty contribution from the spectral responsivity measurement to the temperature scale to be less than 64 mK (k  =  1) in a range from 660 °C to 2749 °C for the LP4 with a filter at 650 nm.

  4. Absorption of monochromatic and narrow band radiation in the visible and near IR by both mitochondrial and non-mitochondrial photoacceptors results in photobiomodulation.

    Science.gov (United States)

    Passarella, Salvatore; Karu, Tiina

    2014-11-01

    In addition to the major functions performed by in the cell, mitochondria play a major role in cell-light interaction. Accordingly it is generally accepted that mitochondria are crucial in cell photobiomodulation; however a variety of biomolecules themselves proved to be targets of light irradiation. We describe whether and how mitochondria can interact with monochromatic and narrow band radiation in the red and near IR optical regions with dissection of both structural and functional effects likely leading to photobiostimulation. Moreover we also report that a variety of biomolecules localized in mitochondria and/or in other cell compartments including cytochrome c oxidase, some proteins, nucleic acids and adenine nucleotides are light sensitive with major modifications in their biochemistry. All together the reported investigations show that the elucidation of the mechanism of the light interaction with biological targets still remains to be completed, this needing further research, however the light sensitivity of a variety of molecules strongly suggests that photobiomodulation could be used in both in photomedicine and in biotechnology.

  5. A new technique to study transient conductivity under pulsed monochromatic light in Cr-doped GaAs using acoustoelectric voltage measurement

    Science.gov (United States)

    Tabib-Azar, Massood

    1991-01-01

    The transient conductivity of high-resistivity Bridgman-grown Cr-doped GaAs under pulsed monochromatic light is monitored using transverse acoustoelectric voltage (TAV) at 83 K. Keeping the photon flux constant, the height and transient time constant at the TAV are used to calculate the energy dependence of the trap density and its cross section, respectively. Two prominent trap profiles with peak trap densities of approximately 10 to the 17th/cu cm eV near the valence and the conduction bands are detected. These traps have very small capture cross sections in the range of 10 to the -23 to 10 to the -21st cm sq. A phenomenon similar to the persistent photoconductivity with transient time constants in excess of a few seconds in high-resistivity GaAs at T = 83 K is also detected using this technique. These long relaxation times are readily explained by the spatial separation of the photo-excited electron-hole pairs and the small capture cross section and large density of trap distribution near the conduction band.

  6. Ultrahigh brilliance quasi-monochromatic MeV γ-rays based on self-synchronized all-optical Compton scattering

    Science.gov (United States)

    Yu, Changhai; Qi, Rong; Wang, Wentao; Liu, Jiansheng; Li, Wentao; Wang, Cheng; Zhang, Zhijun; Liu, Jiaqi; Qin, Zhiyong; Fang, Ming; Feng, Ke; Wu, Ying; Tian, Ye; Xu, Yi; Wu, Fenxiang; Leng, Yuxin; Weng, Xiufeng; Wang, Jihu; Wei, Fuli; Yi, Yicheng; Song, Zhaohui; Li, Ruxin; Xu, Zhizhan

    2016-07-01

    Inverse Compton scattering between ultra-relativistic electrons and an intense laser field has been proposed as a major route to generate compact high-brightness and high-energy γ-rays. Attributed to the inherent synchronization mechanism, an all-optical Compton scattering γ-ray source, using one laser to both accelerate electrons and scatter via the reflection of a plasma mirror, has been demonstrated in proof-of-principle experiments to produce a x-ray source near 100 keV. Here, by designing a cascaded laser wakefield accelerator to generate high-quality monoenergetic e-beams, which are bound to head-on collide with the intense driving laser pulse via the reflection of a 20-um-thick Ti foil, we produce tunable quasi-monochromatic MeV γ-rays (33% full-width at half-maximum) with a peak brilliance of ~3 × 1022 photons s-1 mm-2 mrad-2 0.1% BW at 1 MeV. To the best of our knowledge, it is one order of magnitude higher than ever reported value of its kinds in MeV regime. This compact ultrahigh brilliance γ-ray source may provide applications in nuclear resonance fluorescence, x-ray radiology and ultrafast pump-probe nondestructive inspection.

  7. Reconnection Remnants in the Magnetic Cloud of October 18-19, 1995: A Shock, Monochromatic Wave, Heat Flux Dropout and Energetic Ion Beam

    Science.gov (United States)

    Collier, Michael R.; Szabo, A.; Farrell, W.; Slavin, J. A.; Lepping, R. P.; Fitzenreiter, R.; Thompson, B.; Hamilton, D. C.; Gloeckler, G.; Ho, G. C.

    2000-01-01

    Evidence is presented that the WIND spacecraft observed particle and field signatures on October 18-19, 1995 due to reconnection near the footpoints of a magnetic cloud (i.e., between 1 and 5 solar radii). These signatures include: (1) an internal shock traveling approximately along the axis of the magnetic cloud, (2) a simple compression of the magnetic field consistent with the footpoint magnetic fields being thrust outwards at speeds much greater than the solar wind speed, (3) an electron heat flux dropout occurring within minutes of the shock indicating a topological change resulting from disconnection from the solar surface, (4) a very cold 5 keV proton beam and (5) an associated monochromatic wave. We expect that, given observations of enough magnetic clouds, Wind and other spacecraft will see signatures similar to the ones reported here indicating reconnection. However, these observations require the spacecraft to be fortuitously positioned to observe the passing shock and other signatures and will therefore be associated with only a small fraction of magnetic clouds. Consistent with this, a few magnetic clouds observed by Wind have been found to possess internal shock waves.

  8. Compton scattering monochromatic X-ray source based on X-band multi-bunch linac at the University of Tokyo

    Science.gov (United States)

    Sakamoto, F.; Uesaka, M.; Taniguchi, Y.; Natsui, T.; Hashimoto, E.; Woo, L. K.; Yamamoto, T.; Urakawa, J.; Yoshida, M.; Higo, T.; Fukuda, S.; Kaneko, N.; Nose, H.; Sakae, H.; Nakamura, N.; Yamamoto, M.

    2009-09-01

    We are currently developing a compact monochromatic X-ray source based on laser-electron Compton scattering for the purpose of medical applications at the University of Tokyo. To realize remarkably compact-, high-intensity- and highly stable system, we adopt an X-band (11.424 GHz) multi-bunch linear accelerator (linac) and reliable Q-switch Nd:YAG laser. The injector of the system consists of a 3.5-cell X-band thermionic cathode RF-gun and an alpha magnet. So far, we have continued high-power experiment and beam generation on X-band thermionic cathode RF-gun. However, breakdown was frequently occurred at coaxial structure around the thermionic cathode. In order to resolve the breakdown, we adopt a choke structure around the thermionic cathode. In this paper, the details of Compton scattering X-ray source the University of Tokyo, the experimental results of the X-ray generation, and upgrade of the X-band thermionic cathode RF-gun will be presented.

  9. Spectral CT in patients with small HCC: investigation of image quality and diagnostic accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Peijie; Gao, Jianbo [The First Affiliated Hospital of Zhengzhou University, The Department of Radiology, Zhengzhou, Henan Province (China); Lin, Xiao Zhu; Chen, Kemin [Rui Jin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai (China)

    2012-10-15

    To assess image quality and diagnostic accuracy of monochromatic imaging from spectral CT in patients with small HCC ({<=}3 cm). Twenty-seven patients with 31 HCC underwent spectral CT to generate conventional 140-kVp polychromatic images (group A) and monochromatic images with energy levels from 40 to 140 keV (group B) during the late arterial phase (LAP) and the portal venous phase (PVP). Two-sample t tests compared the tumour-to-liver contrast-to-noise ratio (CNR) and mean image noise. Lesion detection for LAP, reader confidence and readers' subjective evaluations of image quality were recorded. Highest CNRs in group B were distributed at 40, 50 and 70 keV. Higher CNR values and lesion conspicuity scores (LCS) were obtained in group B than in group A (CNR 3.36 {+-} 2.07 vs. 1.47 {+-} 0.89 in LAP; 2.29 {+-} 2.26 vs. 1.58 {+-} 1.75 in PVP; LCS 2.82, 2.84, 2.63 and 2.53 at 40-70 keV, respectively, vs. 1.95) (P < 0.001). Lowest image noise for group B was at 70 keV, resulting in higher image quality than that in group A (4.70 vs. 4.07; P < 0.001). Monochromatic energy levels of 40-70 keV can increase detectability in small HCC and this increase might not result in image quality degradation. (orig.)

  10. IMAGES, IMAGES, IMAGES

    Energy Technology Data Exchange (ETDEWEB)

    Marcus, A.

    1980-07-01

    The role of images of information (charts, diagrams, maps, and symbols) for effective presentation of facts and concepts is expanding dramatically because of advances in computer graphics technology, increasingly hetero-lingual, hetero-cultural world target populations of information providers, the urgent need to convey more efficiently vast amounts of information, the broadening population of (non-expert) computer users, the decrease of available time for reading texts and for decision making, and the general level of literacy. A coalition of visual performance experts, human engineering specialists, computer scientists, and graphic designers/artists is required to resolve human factors aspects of images of information. The need for, nature of, and benefits of interdisciplinary effort are discussed. The results of an interdisciplinary collaboration are demonstrated in a product for visualizing complex information about global energy interdependence. An invited panel will respond to the presentation.

  11. Transmission diamond imaging detector

    Energy Technology Data Exchange (ETDEWEB)

    Smedley, John, E-mail: smedley@bnl.gov; Pinelli, Don; Gaoweia, Mengjia [Brookhaven National Laboratory, Upton, NY (United States); Muller, Erik; Ding, Wenxiang; Zhou, Tianyi [Stony Brook University, Stony Brook, NY (United States); Bohon, Jen [Case Center for Synchrotron Biosciences, Center for Proteomics and Bioinformatics, Case Western Reserve University, Cleveland, OH (United States)

    2016-07-27

    Many modern synchrotron techniques are trending toward use of high flux beams and/or beams which require enhanced stability and precise understanding of beam position and intensity from the front end of the beamline all the way to the sample. For high flux beams, major challenges include heat load management in optics (including the vacuum windows) and a mechanism of real-time volumetric measurement of beam properties such as flux, position, and morphology. For beam stability in these environments, feedback from such measurements directly to control systems for optical elements or to sample positioning stages would be invaluable. To address these challenges, we are developing diamond-based instrumented vacuum windows with integrated volumetric x-ray intensity, beam profile and beam-position monitoring capabilities. A 50 µm thick single crystal diamond has been lithographically patterned to produce 60 µm pixels, creating a >1kilopixel free-standing transmission imaging detector. This device, coupled with a custom, FPGA-based readout, has been used to image both white and monochromatic x-ray beams and capture the last x-ray photons at the National Synchrotron Light Source (NSLS). This technology will form the basis for the instrumented end-station window of the x-ray footprinting beamline (XFP) at NSLS-II.

  12. Reflection type of terahertz imaging system using a high-T{sub c} superconducting oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Kashiwagi, T.; Minami, H.; Kadowaki, K. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Division of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Nakade, K.; Saiwai, Y.; Kitamura, T.; Watanabe, C.; Ishida, K.; Sekimoto, S.; Asanuma, K.; Yasui, T.; Shibano, Y. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Marković, B.; Mirković, J. [Faculty of Sciences, University of Montenegro, George Washington Str., 81000 Podgorica (Montenegro); Tsujimoto, M. [Department of Electronic Science and Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Yamamoto, T. [National Institute for Materials Science, Wide Bandgap Materials Group, Optical and Electronic Materials Unit, Environment and Energy Materials Division, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2014-01-13

    A reflection type of imaging system is shown at sub-terahertz frequencies generated from high-T{sub c} superconducting intrinsic Josephson junction mesa structures fabricated by single crystalline Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+δ} to demonstrate how the sub-terahertz imaging technique using monochromatic radiation is powerful and unique for the variety of practical applications. Several examples are discussed in detail and are compared to other terahertz imaging systems.

  13. Structural and optical properties of AlN grown by solid source solution growth method

    Science.gov (United States)

    Kangawa, Yoshihiro; Suetsugu, Hiroshige; Knetzger, Michael; Meissner, Elke; Hazu, Kouji; Chichibu, Shigefusa F.; Kajiwara, Takashi; Tanaka, Satoru; Iwasaki, Yosuke; Kakimoto, Koichi

    2015-08-01

    Structural and optical properties of AlN grown on AlN(0001) by the solid source solution growth (3SG) method were investigated. Transmission electron microscopy (TEM) analysis revealed that the geometrical relationship between the growth directions and slip planes influenced the dislocation propagation behaviors and annihilation mechanisms. Panchromatic and monochromatic images in the cathodoluminescence (CL) spectrum further revealed that C impurities were segregated near the surface, while Al vacancies were widely distributed in the AlN/AlN(0001) grown using the 3SG method.

  14. Coded Aperture Imaging for Fluorescent X-rays-Biomedical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Haboub, Abdel; MacDowell, Alastair; Marchesini, Stefano; Parkinson, Dilworth

    2013-06-01

    Employing a coded aperture pattern in front of a charge couple device pixilated detector (CCD) allows for imaging of fluorescent x-rays (6-25KeV) being emitted from samples irradiated with x-rays. Coded apertures encode the angular direction of x-rays and allow for a large Numerical Aperture x- ray imaging system. The algorithm to develop the self-supported coded aperture pattern of the Non Two Holes Touching (NTHT) pattern was developed. The algorithms to reconstruct the x-ray image from the encoded pattern recorded were developed by means of modeling and confirmed by experiments. Samples were irradiated by monochromatic synchrotron x-ray radiation, and fluorescent x-rays from several different test metal samples were imaged through the newly developed coded aperture imaging system. By choice of the exciting energy the different metals were speciated.

  15. Nonlinear images of scatterers in chirped pulsed laser beams

    Institute of Scientific and Technical Information of China (English)

    Hu Yong-Hua; Wang You-Wen; Wen Shuang-Chun; Fan Dian-Yuan

    2010-01-01

    The bandwidth and the duration of incident pulsed beam are proved to play important roles in modifying the nonlinear image of amplitude-type scatterer.It is found that the initially positive chirp-type bandwidth can suppress the nonlinear image,while the negative one can enhance it,and that both effects are inversely proportional to the incident pulse duration.Numerical simulations further demonstrate that the location of nonlinear image is at the conjugate plane of the scatterer and that,for negatively pre-chirped pulsed beam,the nonlinear image peak intensity can be higher than that in the corresponding monochromatic case under certain conditions.Moreover the effect of group velocity dispersion on nonlinear image is found to be similar to that of chirp-type bandwidth.

  16. K-edge digital subtraction imaging with dichromatic x-ray sources: SNR and dose studies

    Science.gov (United States)

    Sarnelli, A.; Elleaume, H.; Taibi, A.; Gambaccini, M.; Bravin, A.

    2006-09-01

    The aim of the present work is to analytically evaluate the signal to noise ratio (SNR) and the delivered dose in K-edge digital subtraction imaging (KES) using two types of x-ray sources: a monochromatic x-ray source (available at synchrotron radiation facilities and considered as gold standard) and a quasi-monochromatic compact source. The energy separation ΔE between the two monochromatic beams is 1 keV and 4 keV for the two sources, respectively. The evaluation has been performed for both radiography and computed tomography. Different geometries have been studied to mimic clinical situations. In mammography, a pathology perfused by a contrast agent has been modelled; in angiography, a vessel superimposed to a ventricle or a stand-alone artery stenosis has been studied. The SNR and the skin dose have been calculated as a function of the detail diameter, the contrast agent (iodine and gadolinium), and its concentration in the tissues. Results show that for ΔE = 4 keV a slightly higher delivered dose is required to obtain the same SNR with respect to ΔE < 1 keV. A similar study has been performed for KES-CT. Computer simulations of CT images performed with Snark software are shown to validate the analytical calculations.

  17. Physiological crosstalk between the AC/PKA and PLC/PKC pathways modulates melatonin-mediated, monochromatic-light-induced proliferation of T-lymphocytes in chickens.

    Science.gov (United States)

    Guo, Qingyun; Wang, Zixu; Dong, Yulan; Cao, Jing; Chen, Yaoxing

    2017-06-28

    Previous study has demonstrated that melatonin plays a critical role in monochromatic-light-induced lymphocyte proliferation in response to T cell mitogen concanavalin A (ConA). However, its intracellular mechanism is still unclear. In this study, we investigate the intracellular signal pathways of melatonin receptor-mediated T-lymphocyte proliferation in the spleens of chicks exposed to different light wavelengths. Results showed that green light enhanced T-lymphocyte proliferation by 2.46-6.83% and increased splenic mRNA and protein expressions of melatonin receptor subtypes (Mel1a, Mel1b and Mel1c) by 16.05-40.43% compared with the white, red and blue light groups. However, pinealectomy resulted in a decrease in T-lymphocyte proliferation and melatonin receptor expression with no statistically significant differences between the different light groups. In vitro experiments showed that the Mel1b selective antagonist 4P-PDOT, the Mel1c selective antagonist prazosin and the mitogen-activated protein kinase kinase-1 (MEK-1) inhibitor PD98059 suppressed both melatonin-induced lymphocyte proliferation in response to ConA and melatonin- and ConA-stimulated extracellular signal-regulated kinase 1/2 (ERK1/2) activity but that the Mel1a/Mel1b non-selective antagonist luzindole did not. In addition, pretreatment with forskolin (FSK, the adenylyl cyclase activator), H89 (the PKA inhibitor), U73122 (the PLC inhibitor) or Go6983 (the broad spectrum PKC inhibitor) markedly attenuated melatonin- and ConA-stimulated T-lymphocyte proliferation and ERK1/2 activity. These results demonstrate that melatonin mediates green-light-induced T-lymphocyte proliferation via the Mel1b and Mel1c receptors by triggering crosstalk between the cAMP/PKA and PLC/PKC signal pathways followed by ERK1/2 activation.

  18. Characterization of morphology and hydration products of high-volume fly ash paste by monochromatic scanning x-ray micro-diffraction (μ-SXRD)

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Sungchul [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States); Meral, Cagla [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States); Department of Civil Engineering, Middle East Technical University, 06800 Ankara (Turkey); Oh, Jae-eun [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798 (Korea, Republic of); Moon, Juhyuk [Civil Engineering Program, Department of Mechanical Engineering, State University of New York at Stony Brook, NY 11794 (United States); Kunz, Martin [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Monteiro, Paulo J.M., E-mail: monteiro@ce.berkeley.edu [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)

    2014-05-01

    The present study focuses on identification and micro-structural characterization of the hydration products formed in high-volume fly ash (HVFA)/portland cement (PC) systems using monochromatic scanning x-ray micro-diffraction (μ-SXRD) and SEM-EDS. Pastes with up to 80% fly ash replacement were studied. Phase maps for HVFA samples using μ-SXRD patterns prove that μ-SXRD is an effective method to identify and visualize the distribution of phases in the matrix. μ-SXRD and SEM-EDS analysis shows that the C-S-H formed in HVFA system containing 50% or more of fly ash has a similar structure as C-S-H(I) with comparatively lower Ca/Si ratio than the one produced in PC system. Moreover, coexistence of C-S-H(I) and strätlingite is observed in the system containing 80% of fly ash, confirming that the amount of alumina and silicate phases provided by the fly ash is a major factor for the formation of C-S-H(I) and strätlingite in HVFA system. - Highlights: • High-volume fly ash (HVFA) paste was studied by scanning x-ray micro-diffraction. • Coexistence of C-S-H(I) and strätlingite in the HVFA system is clearly shown. • The distribution of minor phases in the HVFA system is shown. • Differences between inner and outer products of fly ash are observed by SEM-EDS.

  19. Effects of monochromatic infrared phototherapy in patients with diabetic peripheral neuropathy: a systematic review and meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Robinson, Caroline Cabral; Klahr, Patrícia Da Silva; Stein, Cinara; Falavigna, Maicon; Sbruzzi, Graciele; Plentz, Rodrigo Della Méa

    Monochromatic infrared energy (MIRE) or phototherapy has been used to improve plantar sensitivity and pain in lower limbs of patients with diabetic sensorimotor peripheral neuropathy (DSPN), but the available primary results are inconsistent. To review systematically the effects of MIRE on plantar sensitivity and neuropathic pain in patients with DSPN. Medline, EMBASE, Cochrane CENTRAL, and Google Scholar were searched up to September 2016. Randomized controlled trials addressing the effects of MIRE on plantar sensitivity and neuropathic pain in patients with DSPN were selected. Study inclusion, risk of bias and quality assessment, and data extraction were completed by two independent reviewers. Of 2549 records identified, six studies met the selection criteria, with 304 patients (594 feet) randomized. MIRE was not associated with improvement in plantar tactile sensitivity (SMD=0.22, 95%CI -0.07 to 0.51, low quality of evidence). Subgroups of studies with short-term (up to 2 weeks) follow-up showed significant improvement in plantar sensitivity (SMD=0.41, 95% CI 0.18-0.64). Neuropathic pain increased significantly in patients who received MIRE (MD=0.49, 95% CI 0.30-0.68, low quality of evidence). There was limited evidence that MIRE results in short-term improvement of tactile sensitivity probably not sustained over time. Limited evidence also suggested that MIRE does not provide relief for neuropathic pain. As quality of evidence is low, further studies are likely to change the estimated effect. Copyright © 2017 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights reserved.

  20. Spatial luminescence imaging of dopant incorporation in CdTe Films

    Science.gov (United States)

    Guthrey, Harvey; Moseley, John; Colegrove, Eric; Burst, James; Albin, David; Metzger, Wyatt K.; Al-Jassim, Mowafak

    2017-01-01

    State-of-the-art cathodoluminescence (CL) spectrum imaging with spectrum-per-pixel CL emission mapping is applied to spatially profile how dopant elements are incorporated into Cadmium telluride (CdTe). Emission spectra and intensity monitor the spatial distribution of additional charge carriers through characteristic variations in the CL emission based on computational modeling. Our results show that grain boundaries play a role in incorporating dopants in CdTe exposed to copper, phosphorus, and intrinsic point defects in CdTe. The image analysis provides critical, unique feedback to understand dopant incorporation and activation in the inhomogeneous CdTe material, which has struggled to reach high levels of hole density.

  1. Spatial luminescence imaging of dopant incorporation in CdTe Films

    Energy Technology Data Exchange (ETDEWEB)

    Guthrey, Harvey; Moseley, John; Colegrove, Eric; Burst, James; Albin, David; Metzger, Wyatt K.; Al-Jassim, Mowafak

    2017-01-28

    State-of-the-art cathodoluminescence (CL) spectrum imaging with spectrum-per-pixel CL emission mapping is applied to spatially profile how dopant elements are incorporated into Cadmium telluride (CdTe). Emission spectra and intensity monitor the spatial distribution of additional charge carriers through characteristic variations in the CL emission based on computational modeling. Our results show that grain boundaries play a role in incorporating dopants in CdTe exposed to copper, phosphorus, and intrinsic point defects in CdTe. The image analysis provides critical, unique feedback to understand dopant incorporation and activation in the inhomogeneous CdTe material, which has struggled to reach high levels of hole density.

  2. A Monochromatic electron neutrino beam

    CERN Document Server

    Lindroos, Mats; Burguet-Castell, J; Espinoza, C

    In the last few years spectacular results have been achieved with the demonstration of non vanishingneutrino masses and flavour mixing. Here, a novel method to create a monochromaticneutrino beam, an old dream for neutrino physics, is described based on the recent discoveryof nuclei with fast decay through electron-capture to Gamow-Teller resonances in super allowedtransitions.

  3. Imaging performance of phase-contrast breast computed tomography with synchrotron radiation and a CdTe photon-counting detector.

    Science.gov (United States)

    Sarno, A; Mettivier, G; Golosio, B; Oliva, P; Spandre, G; Di Lillo, F; Fedon, C; Longo, R; Russo, P

    2016-05-01

    Within the SYRMA-CT collaboration based at the ELETTRA synchrotron radiation (SR) facility the authors investigated the imaging performance of the phase-contrast computed tomography (CT) system dedicated to monochromatic in vivo 3D imaging of the female breast, for breast cancer diagnosis. Test objects were imaged at 38keV using monochromatic SR and a high-resolution CdTe photon-counting detector. Signal and noise performance were evaluated using modulation transfer function (MTF) and noise power spectrum. The analysis was performed on the images obtained with the application of a phase retrieval algorithm as well as on those obtained without phase retrieval. The contrast to noise ratio (CNR) and the capability of detecting test microcalcification clusters and soft masses were investigated. For a voxel size of (60μm)(3), images without phase retrieval showed higher spatial resolution (6.7mm(-1) at 10% MTF) than corresponding images with phase retrieval (2.5mm(-1)). Phase retrieval produced a reduction of the noise level and an increase of the CNR by more than one order of magnitude, compared to raw phase-contrast images. Microcalcifications with a diameter down to 130μm could be detected in both types of images. The investigation on test objects indicates that breast CT with a monochromatic SR source is technically feasible in terms of spatial resolution, image noise and contrast, for in vivo 3D imaging with a dose comparable to that of two-view mammography. Images obtained with the phase retrieval algorithm showed the best performance in the trade-off between spatial resolution and image noise. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  4. A regularized tri-linear approach for optical interferometric imaging

    Science.gov (United States)

    Birdi, Jasleen; Repetti, Audrey; Wiaux, Yves

    2017-06-01

    In the context of optical interferometry, only undersampled power spectrum and bispectrum data are accessible. It poses an ill-posed inverse problem for image recovery. Recently, a tri-linear model was proposed for monochromatic imaging, leading to an alternated minimization problem. In that work, only a positivity constraint was considered, and the problem was solved by an approximated Gauss-Seidel method. In this paper, we propose to improve the approach on three fundamental aspects. First, we define the estimated image as a solution of a regularized minimization problem, promoting sparsity in a fixed dictionary using either an ℓ1 or a (re)weighted-ℓ1 regularization term. Secondly, we solve the resultant non-convex minimization problem using a block-coordinate forward-backward algorithm. This algorithm is able to deal both with smooth and non-smooth functions, and benefits from convergence guarantees even in a non-convex context. Finally, we generalize our model and algorithm to the hyperspectral case, promoting a joint sparsity prior through an ℓ2,1 regularization term. We present simulation results, both for monochromatic and hyperspectral cases, to validate the proposed approach.

  5. Orbital effects of a monochromatic plane gravitational wave with ultra-low frequency incident on a gravitationally bound two-body system

    Directory of Open Access Journals (Sweden)

    Lorenzo Iorio

    2014-09-01

    Full Text Available We analytically compute the long-term orbital variations of a test particle orbiting a central body acted upon by an incident monochromatic plane gravitational wave. We assume that the characteristic size of the perturbed two-body system is much smaller than the wavelength of the wave. Moreover, we also suppose that the wave's frequency νg is much smaller than the particle's orbital one nb. We make neither a priori assumptions about the direction of the wavevector kˆ nor on the orbital configuration of the particle. While the semi-major axis a is left unaffected, the eccentricity e, the inclination I, the longitude of the ascending node Ω, the longitude of pericenter ϖ and the mean anomaly ℳ undergo non-vanishing long-term changes of the form dΨ/dt=F(Kij;e,I,Ω,ω,Ψ=e,I,Ω,ϖ,M, where Kij, i,j=1,2,3 are the coefficients of the tidal matrix K. Thus, in addition to the variations of its orientation in space, the shape of the orbit would be altered as well. Strictly speaking, such effects are not secular trends because of the slow modulation introduced by K and by the orbital elements themselves: they exhibit peculiar long-term temporal patterns which would be potentially of help for their detection in multidecadal analyses of extended data records of planetary observations of various kinds. In particular, they could be useful in performing independent tests of the inflation-driven ultra-low gravitational waves whose imprint may have been indirectly detected in the Cosmic Microwave Background by the Earth-based experiment BICEP2. Our calculation holds, in general, for any gravitationally bound two-body system whose orbital frequency nb is much larger than the frequency νg of the external wave, like, e.g., extrasolar planets and the stars orbiting the Galactic black hole. It is also valid for a generic perturbation of tidal type with constant coefficients over timescales of the order of the orbital period of the perturbed particle.

  6. Cherenkov detectors for spatial imaging applications using discrete-energy photons

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Paul B.; Erickson, Anna S., E-mail: erickson@gatech.edu [Georgia Institute of Technology, Nuclear and Radiological Engineering, G.W. Woodruff School of Mechanical Engineering, 770 State St., Atlanta, Georgia 30332 (United States)

    2016-08-14

    Cherenkov detectors can offer a significant advantage in spatial imaging applications when excellent timing response, low noise and cross talk, large area coverage, and the ability to operate in magnetic fields are required. We show that an array of Cherenkov detectors with crude energy resolution coupled with monochromatic photons resulting from a low-energy nuclear reaction can be used to produce a sharp image of material while providing large and inexpensive detector coverage. The analysis of the detector response to relative transmission of photons with various energies allows for reconstruction of material's effective atomic number further aiding in high-Z material identification.

  7. Cherenkov detectors for spatial imaging applications using discrete-energy photons

    Science.gov (United States)

    Rose, Paul B.; Erickson, Anna S.

    2016-08-01

    Cherenkov detectors can offer a significant advantage in spatial imaging applications when excellent timing response, low noise and cross talk, large area coverage, and the ability to operate in magnetic fields are required. We show that an array of Cherenkov detectors with crude energy resolution coupled with monochromatic photons resulting from a low-energy nuclear reaction can be used to produce a sharp image of material while providing large and inexpensive detector coverage. The analysis of the detector response to relative transmission of photons with various energies allows for reconstruction of material's effective atomic number further aiding in high-Z material identification.

  8. X-ray imaging with a silicon microstrip detector coupled to the RX64 ASIC

    Energy Technology Data Exchange (ETDEWEB)

    Baldazzi, G.; Bollini, D.; Cabal Rodriguez, A.E.; Dabrowski, W.; Diaz Garcia, A.; Gambaccini, M.; Giubellino, P.; Gombia, M.; Grybos, P.; Idzik, M.; Marzari-Chiesa, A.; Montano Zetina, L.M.; Prino, F.; Ramello, L. E-mail: ramello@to.infn.it; Sitta, M.; Swientek, K.; Taibi, A.; Tuffanelli, A.; Wheadon, R.; Wiacek, P

    2003-08-21

    A single photon counting X-ray imaging system, with possible applications to dual energy mammography and angiography, is presented. A silicon microstrip detector with 100 {mu}m pitch strips is coupled to RX64 ASICs, each of them including 64 channels of preamplifier, shaper, discriminator and scaler. The system has low noise, good spatial resolution and high counting rate capability. Results on energy resolution have been obtained with a fluorescence source and quasi-monochromatic X-rays beams. Preliminary images obtained with an angiographic phantom are presented.

  9. Optical encryption in spatially-incoherent light using two LC SLMs for both information input and encryption element imaging

    Science.gov (United States)

    Bondareva, Alyona P.; Cheremkhin, Pavel A.; Evtikhiev, Nikolay N.; Krasnov, Vitaly V.; Rodin, Vladislav G.; Starikov, Sergey N.

    2014-10-01

    At present time methods of optical encryption are actively developed. The majority of existing methods of optical encryption use not only light intensity distribution, easily registered with photosensors, but also its phase distribution which require application of complex holographic schemes in conjunction with spatially coherent monochromatic illumination. This leads to complex optical schemes and low decryption quality. To eliminate these disadvantages it is possible to implement optical encryption using spatially incoherent monochromatic illumination which requires registration of light intensity distribution only. Encryption is accomplished by means of optical convolution of image of scene to be encrypted and encryption diffractive optical element (DOE) point spread function (PSF) which serves as encryption key. Encryption process is described as follows. Scene is illuminated with spatially-incoherent monochromatic light. In the absence of encryption DOE lens forms image of scene in photosensor plane. DOE serves as encryption element, its PSF - encryption key. Light passing through DOE forms convolution of object image and DOE PSF. Registered by photosensor convolution is encrypted image. Decryption was conducted numerically on computer by means of inverse filtration with regularization. Kinoforms were used as encryption DOE because they have single diffraction order. Two liquid crystal (LC) spatial light modulators (SLM) were used to implement dynamic digital information input and dynamic encryption key change. As input scene amplitude LC SLM HoloEye LC2002 with 800×600 pixels 32×32 μm2 and 256 gray levels was used. To image synthesized encryption kinoforms phase LC SLM HoloEye PLUTO VIS with 1920×1080 pixels 8×8 μm2 and 256 phase levels was used. Set of test images was successfully optically encrypted and then numerically decrypted. Encrypted images contents are hidden. Decrypted images despite quite high noise levels are positively recognizable

  10. WE-A-BRF-01: Dual-Energy CT Imaging in Diagnostic Imaging and Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Molloi, S [University of California, Irvine, CA (United States); Li, B [Boston University Medical Center, Boston, MA (United States); Yin, F [Duke University Medical Center, Durham, NC (United States); Chen, H [New York Presbyterian Hospital, New York, NY (United States)

    2014-06-15

    The quantification accuracy of dual-energy imaging is influenced by the fundamentals of x-ray physics, system geometry, data acquisition hardware/protocol, system calibration, and image processing technique. This symposium will provide updates on the following advanced application areas: Mammography. Volumetric breast density techniques based on standard mammograms require estimation of breast thickness, which is difficult to accurately measure. By comparison, calculation of breast density using dual energy mammography does not require measurement of breast thickness. Dual energy mammography has been implemented using both energy integrating flat panel detectors in conjunction with beam energy switching and energy resolved photon counting detectors. These techniques have been optimized using simulation studies and validated using physical phantoms and postmortem breasts. Chemical decomposition was used as the gold standard for volumetric breast density measurement in postmortem breasts. Breast density measurements have also been compared with results from four-category BI-RADS density rankings, standard image thresholding and Fuzzy k-mean clustering techniques. These studies indicate that dual energy mammography can be used to accurately measure volumetric breast density. Cardiovascular CT. The predicative accuracy of risk models for recurrent stroke and cardiac arrest depends heavily on accurate differentiation of thrombus or calcium from iodine in left atrial appendage or coronary arteries. The amount of energy separation is constrained by image noise; therefore, optimal kVp, beam filtration, and balanced flux are essential for the quantification accuracy of iodine and calcium. The basis materials are combined linearly to generate monochromatic energy images, where CT# accuracy and CNR are energy dependent. With optimal monochromatic energy, the mean iodine concentration for the thrombus, circulatory stasis, and control groups are significantly different. Risk

  11. Pulsed cathodoluminescence and Raman spectra of MoS{sub 2} and WS{sub 2} nanocrystals and their combination MoS{sub 2}/WS{sub 2} produced by self-propagating high-temperature synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Bozheyev, Farabi, E-mail: farabi.bozheyev@gmail.com [Institute of High Technology Physics, National Research Tomsk Polytechnic University, 30 Lenin Ave., 634050 Tomsk (Russian Federation); National Nanolaboratory, al-Farabi Kazakh National University, 71 al-Farabi Ave., 050000 Almaty (Kazakhstan); Nazarbayev University Research and Innovation System, 53 Kabanbay Batyr St., 010000 Astana (Kazakhstan); Valiev, Damir [Institute of High Technology Physics, National Research Tomsk Polytechnic University, 30 Lenin Ave., 634050 Tomsk (Russian Federation); Nemkayeva, Renata [National Nanolaboratory, al-Farabi Kazakh National University, 71 al-Farabi Ave., 050000 Almaty (Kazakhstan)

    2016-02-29

    Molybdenum and tungsten disulfide nanoplates were produced by self-propagating high-temperature synthesis in argon atmosphere. This method provides an easy way to produce MoS{sub 2} and WS{sub 2} from nanoplates up to single- and several layers. The Raman peak intensities corresponding to in-plane E{sup 1}{sub 2g} and out-of-plane A{sub 1g} vibration modes and their shifts strongly depend on the thicknesses of the MoS{sub 2} and WS{sub 2} platelets indicating size-dependent scaling laws and properties. An electron beam irradiation of MoS{sub 2} and WS{sub 2} powders leads to an occurrence of pulsed cathodoluminescence (PCL) spectra at 575 nm (2.15 eV) and 550 nm (2.25 eV) characteristic to their intrinsic band gaps. For the combination of MoS{sub 2} and WS{sub 2} nanopowders, a PCL shoulder at 430 nm (2.88 eV) was observed, which is explained by the radiative electron-hole recombination at the MoS{sub 2}/WS{sub 2} grain boundaries. The luminescence decay kinetics of the MoS{sub 2}/WS{sub 2} nanoplates appears to be slower than for individual MoS{sub 2} and WS{sub 2} platelets due to a spatial separation of electrons and holes at MoS{sub 2}/WS{sub 2} junction resulting in extension of recombination time.

  12. Temperature dependence of exciton-surface plasmon polariton coupling in Ag, Au, and Al films on In{sub x}Ga{sub 1−x}N/GaN quantum wells studied with time-resolved cathodoluminescence

    Energy Technology Data Exchange (ETDEWEB)

    Estrin, Y.; Rich, D. H., E-mail: danrich@bgu.ac.il [Department of Physics and The Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, P.O.B 653, Beer-Sheva 84105 (Israel); Keller, S.; DenBaars, S. P. [Electrical and Computer Engineering and Materials Departments, University of California, Santa Barbara, California 93111 (United States)

    2015-01-28

    The optical properties and coupling of excitons to surface plasmon polaritons (SPPs) in Ag, Au, and Al-coated In{sub x}Ga{sub 1−x}N/GaN multiple and single quantum wells (SQWs) were probed with time-resolved cathodoluminescence. Excitons were generated in the metal coated SQWs by injecting a pulsed high-energy electron beam through the thin metal films. The Purcell enhancement factor (F{sub p}) was obtained by direct measurement of changes in the temperature-dependent radiative lifetime caused by the SQW exciton-SPP coupling. Three chosen plasmonic metals of Al, Ag, and Au facilitate an interesting comparison of the exciton-SPP coupling for energy ranges in which the SP energy is greater than, approximately equal to, and less than the excitonic transition energy for the InGaN/GaN QW emitter. A modeling of the temperature dependence of the Purcell enhancement factor, F{sub p}, included the effects of ohmic losses of the metals and changes in the dielectric properties due to the temperature dependence of (i) the intraband behavior in the Drude model and (ii) the interband critical point transition energies which involve the d-bands of Au and Ag. We show that an inclusion of both intraband and interband effects is essential when calculating the ω vs k SPP dispersion relation, plasmon density of states (DOS), and the dependence of F{sub p} on frequency and temperature. Moreover, the “back bending” in the SPP dispersion relation when including ohmic losses can cause a finite DOS above ω{sub sp} and lead to a measurable F{sub p} in a limited energy range above ω{sub sp}, which can potentially be exploited in plasmonic devices utilizing Ag and Au.

  13. Imaging system of wavelet optics described by the Gaussian linear frequency-modulated complex wavelet

    Science.gov (United States)

    Tan, Liying; Ma, Jing; Wang, Guangming

    2005-12-01

    The image formation and the point-spread function of an optical system are analyzed by use of the wavelet basis function. The image described by a wavelet is no longer an indivisible whole image. It is, rather, a complex image consisting of many wavelet subimages, which come from the changes of different parameters (scale) a and c, and parameters b and d show the positions of wavelet subimages under different scales. A Gaussian frequency-modulated complex-valued wavelet function is introduced to express the point-spread function of an optical system and used to describe the image formation. The analysis, in allusion to the situation of illumination with a monochromatic plain light wave, shows that using the theory of wavelet optics to describe the image formation of an optical system is feasible.

  14. Recent developments on techniques for differential phase imaging at the medical beamline of ELETTRA

    Science.gov (United States)

    Arfelli, F.; Pelliccia, D.; Cedola, A.; Astolfo, A.; Bukreeva, I.; Cardarelli, P.; Dreossi, D.; Lagomarsino, S.; Longo, R.; Rigon, L.; Sodini, N.; Menk, R. H.

    2013-06-01

    Over the last decade different phase contrast approaches have been exploited at the medical beamline SYRMEP of the synchrotron radiation facility Elettra in Trieste, Italy. In particular special focus has been drawn to analyzer based imaging and the associated imaging theory and processing. Analyzer based Imaging (ABI) and Diffraction Enhanced Imaging (DEI) techniques have been successfully applied in several biomedical applications. Recently it has been suggested to translate the acquired knowledge in this field towards a Thomson Backscattering Source (TBS), which is presently under development at the Frascati National Laboratories of INFN (Istituto Nazionale di Fisica Nucleare) in Rome, Italy. Such source is capable of producing intense and quasi-monochromatic hard X-ray beams. For the technical implementation of biomedical phase imaging at the TBS a grating interferometer for differential phase contrast imaging has been designed and successfully tested at SYRMEP beamline.

  15. Spectrum multiplexing and coherent-state decomposition in Fourier ptychographic imaging

    CERN Document Server

    Dong, Siyuan; Nanda, Pariksheet; Zheng, Guoan

    2014-01-01

    Information multiplexing is important for biomedical imaging and chemical sensing. In this paper, we report a microscopy imaging technique, termed state-multiplexed Fourier ptychography (FP), for information multiplexing and coherent-state decomposition. Similar to a typical Fourier ptychographic setting, we use an array of light sources to illuminate the sample from different incident angles and acquire corresponding low-resolution images using a monochromatic camera. In the reported technique, however, multiple light sources are lit up simultaneously for information multiplexing, and the acquired images thus represent incoherent summations of the sample transmission profiles corresponding to different coherent states. We show that, by using the state-multiplexed FP recovery routine, we can decompose the incoherent mixture of the FP acquisitions to recover a high-resolution sample image. We also show that, color-multiplexed imaging can be performed by simultaneously turning on R/G/B LEDs for data acquisition...

  16. Diffraction-enhanced imaging of the rat spine

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, M.E. [Cleveland Clinic, Dept. of Neurosurgery, Cleveland, Ohio (United States)]. E-mail: mebkelly@gmail.com; Beavis, R.C. [Univ. of Saskatchewan, Royal Univ. Hospital, Div. of Orthopaedic Surgery, Saskatoon, Saskatchewan (Canada); Fourney, D.R. [Univ. of Saskatchewan, Royal Univ. Hospital, Div. of Neurosurgery, Saskatoon, Saskatchewan (Canada); Schultke, E. [Univ. of Saskatchewan, Dept. of Anatomy and Cell Biology, Saskatoon, Saskatchewan (Canada); Parham, C. [Univ. of North Carolina, Dept. of Biomedical Engineering, Chapel Hill, North Carolina (United States); Juurlink, B.H. [Univ. of Saskatchewan, Dept. of Anatomy and Cell Biology, Saskatoon, Saskatchewan (Canada); Zhong, Z. [Brookhaven National Laboratory, National Synchrotron Light Source, Upton, New York (United States); Chapman, L.D. [Univ. of Saskatchewan, Dept. of Anatomy and Cell Biology, Saskatoon, Saskatchewan (Canada)

    2006-10-15

    Diffraction-enhanced imaging (DEI) uses monochromatic synchrotron X-rays to image tissue. This technique has been shown to produce superior bony and soft tissue characterization when compared with conventional absorption radiography. Application of this imaging modality is under investigation, and this study represents the first DEI analysis of the vertebral column. Four male Wistar rats were studied. Spine muscle blocks were imaged in 3 of the rats after thoracic laminectomy (n = 1), after lumbar laminectomy (n = 1), and in a control condition (n = 1). The fourth rat was imaged as a whole animal control. Conventional radiography and synchrotron-supported DEI at 40 keV were performed on all specimens. We compared images side by side, using a nonvalidated subjective assessment technique. DEI produced superior visualization of the vertebral anatomy, compared with conventional absorption radiography for all specimens. Greater bony and soft tissue detail was noted, with improved image contrast. In addition to imaging the anatomical structures, DEI showed the polyglactin suture material used for fascial closure in the 2 animals that underwent surgery. Artifact from air bubbles was present on DEI images but not on plain radiographs. This represents the first use of DEI, a novel imaging modality, to image the vertebral column. It provides excellent anatomic detail with superior contrast and visualization of both bone and soft tissue when compared with conventional radiography. Future applications of this investigational technique may include analysis of spinal fusion as well as degenerative and neoplastic conditions of the spine. (author)

  17. Specification of multiple image characteristics viewed through a grating

    Science.gov (United States)

    Abolhassani, Mohammad

    2016-11-01

    When a person observes an object, illuminated incoherently by a quasi-monochromatic source, through a grating, he will see more than one image. Angular positions of these images are derived in terms of wavelength, period of the grating, separation between the object and the grating, and position of the object relative to the observer. In a special case, when the object is another grating, the condition of coincidence of its multiple images is investigated. The relation derived is, to some extent, similar to that seen in the Lau effect. As a secondary outcome, it is shown that the sum of the squared modulus of the odd Fourier series coefficients for a binary grating function is equal to that of the even coefficients.

  18. CMOS APS detector characterization for quantitative X-ray imaging

    Energy Technology Data Exchange (ETDEWEB)

    Endrizzi, Marco, E-mail: m.endrizzi@ucl.ac.uk [Dipartimento di Fisica, Università di Siena, Via Roma 56, 53100 Siena (Italy); Istituto Nazionale di Fisica Nucleare INFN, sezione di Pisa, 56127 Pisa (Italy); Oliva, Piernicola [Dipartimento di Chimica e Farmacia, Università di Sassari, via Piandanna 4, 07100 Sassari (Italy); Istituto Nazionale di Fisica Nucleare INFN, Sezione di Cagliari, 09042 Cagliari (Italy); Golosio, Bruno [Sezione di Matematica, Fisica e Ingegneria dell' Informazione, Università di Sassari, via Piandanna 4, 07100 Sassari (Italy); Istituto Nazionale di Fisica Nucleare INFN, Sezione di Cagliari, 09042 Cagliari (Italy); Delogu, Pasquale [Dipartimento di Fisica “E. Fermi”, Università di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Istituto Nazionale di Fisica Nucleare INFN, sezione di Pisa, 56127 Pisa (Italy)

    2013-03-01

    An X-ray Imaging detector based on CMOS Active Pixel Sensor and structured scintillator is characterized for quantitative X-ray imaging in the energy range 11–30 keV. Linearity, dark noise, spatial resolution and flat-field correction are the characteristics of the detector subject of investigation. The detector response, in terms of mean Analog-to-Digital Unit and noise, is modeled as a function of the energy and intensity of the X-rays. The model is directly tested using monochromatic X-ray beams and it is also indirectly validated by means of polychromatic X-ray-tube spectra. Such a characterization is suitable for quantitative X-ray imaging and the model can be used in simulation studies that take into account the actual performance of the detector.

  19. Chromaffin cell calcium signal and morphology study based on multispectral images

    Science.gov (United States)

    Wu, Hongxiu; Wei, Shunhui; Qu, Anlian; Zhou, Zhuan

    1998-09-01

    Increasing or decreasing the internal calcium concentration can promote or prevent programmed cell death (PCD). We therefore performed a Ca2+ imaging study using Ca2+ indicator dye fura-2 and a sensitive cooled-CCD camera with a 12 bit resolution. Monochromatic beams of light with a wavelength of 345,380 nm were isolated from light emitted by a xenon lamp using a monochromator. The concentration of free calcium can be directly calculated from the ratio of two fluorescence values taken at two appropriately selected wavelength. Fluorescent light emitted from the cells was capture using a camera system. The cell morphology study is based on multispectral scanning, with smear images provided as three monochromatic images by illumination with light of 610,535 and 470 nm wavelengths. The nuclear characteristic parameters extracted from individual nuclei by system are nuclear area, nuclear diameter, nuclear density vector. The results of the restoration of images and the performance of a primitive logic for the detection of nuclei with PCD proved the usefulness of the system and the advantages of using multispectral images in the restoration and detection procedures.

  20. Panoramic, Macro and Micro Multispectral Imaging: An Affordable System for Mapping Pigments on Artworks

    Directory of Open Access Journals (Sweden)

    Antonino Cosentino

    2015-07-01

    Full Text Available Multispectral imaging systems are used in art examinations to map and identify pigments, binders and areas of retouching. A monochromatic camera is combined with an appropriate wavelength selection system and acquires a variable number of spectral images of a scene. These images are then stacked into a reflectance imaging cube to reconstruct reflectance spectra from each of the images’ pixels. This paper presents an affordable multispectral imaging system composed of a monochromatic CCD camera and a set of only 12 interference filters for mapping pigments on works of art and for the tentative identification of such pigments. This work demonstrates the versatility of this set-up, a versatility enabling it to be applied to different tasks, involving examination and documentation of objects of varying size. Use of this multispectral camera for both panoramic and macro photography is discussed, together with the possibilities facilitated from the coupling of the system to a stereomicroscope and a compound microscope. This system is of particular interest for the cultural heritage sector because of its hardware simplicity and acquisition speed, as well as its lightness and small dimensions.

  1. Scatter free imaging for the improvement of breast cancer detection in mammography

    Science.gov (United States)

    Green, F. H.; Veale, M. C.; Wilson, M. D.; Seller, P.; Scuffham, J.; Pani, S.

    2016-10-01

    In mammography, the reduction of scattered x-rays is vital due to the low contrast or small dimension of the details that are searched for. The typical method of doing so in current conventional mammography is the anti-scatter grid. The disadvantage of this method is the absorption of a proportion of the primary beam and therefore an increase in dose is required to compensate for the loss of counts. An alternative method is proposed, using quasi-monochromatic beams and a pixellated spectroscopic detector. As Compton-scattered x-rays lose energy in the scattering process, they are detected at a lower energy in the spectrum. Therefore the spectrum can be windowed around the monochromatic energy peak, removing the scattered x-rays from the image. The work presented here shows contrast improvement of up to 50% and contrast to noise ratio improvements of around 20% for scatter free imaging in comparison to full spectrum imaging. Contrast improvements of around 45% were found when comparing scatter free images to conventional polychromatic imaging for both the low contrast test object and the Rachel anthropomorphic breast phantom.

  2. Mars Digital Image Mosaic Globe

    Science.gov (United States)

    2000-01-01

    The photomosaic that forms the base for this globe was created by merging two global digital image models (DIM's) of Mars-a medium-resolution monochrome mosaic processed to emphasize topographic features and a lower resolution color mosaic emphasizing color and albedo variations.The medium-resolution (1/256 or roughly 231 m/pixel) monochromatic image model was constructed from about 6,000 images having resolutions of 150-350 m/pixel and oblique illumination (Sun 20 o -45 o above the horizon). Radiometric processing was intended to suppress or remove the effects of albedo variations through the use of a high-pass divide filter, followed by photometric normalization so that the contrast of a given topographic slope would be approximately the same in all images.The global color mosaic was assembled at 1/64 or roughly 864 m/pixel from about 1,000 red- and green-filter images having 500-1,000 m/pixel resolution. These images were first mosaiced in groups, each taken on a single orbit of the Viking spacecraft. The orbit mosaics were then processed to remove spatially and temporally varying atmospheric haze in the overlap regions. After haze removal, the per-orbit mosaics were photometrically normalized to equalize the contrast of albedo features and mosaiced together with cosmetic seam removal. The medium-resolution DIM was used for geometric control of this color mosaic. A green-filter image was synthesized by weighted averaging of the red- and violet-filter mosaics. Finally, the product seen here was obtained by multiplying each color image by the medium-resolution monochrome image. The color balance selected for images in this map series was designed to be close to natural color for brighter, redder regions, such as Arabia Terra and the Tharsis region, but the data have been stretched so that the relatively dark regions appear darker and less red than they actually are.The images are presented in a projection that portrays the entire surface of Mars in a manner

  3. CT能谱单能量成像用于提高脑血管CTA成像质量%Spectral CT monochromatic imaging in improving the image quality of head CT angiography

    Institute of Scientific and Technical Information of China (English)

    廖海; 邓德茂; 黄增超; 万荣超; 陈燕静; 袁捷; 陈加军; 李敏; 何欣

    2014-01-01

    目的 探讨CT能谱单能量图像对提高脑血管CTA成像质量的价值.方法 回顾性分析53例接受脑血管能谱CTA检查的患者,获得5组单能量图像(50、70、90、110、130 keV)、1组质量控制(QC)图像.分别测定6组图像的噪声、CNR,并对图像质量进行评分.采用单因素方差分析比较6组图像的CNR及噪声差异,组间两两比较采用LSD-t检验;采用多组独立样本秩和检验(K ruskal-Wallis H)比较图像质量评分差异.结果 6组中,70 keV组与90 keV组图像噪声差异无统计学意义(P>0.05),其余各组间两两比较差异均有统计学意义(P均<0.05);6组图像CNR、图像质量评分两两比较差异均有统计学意义(P均<0.05),50 keV单能量图CNR、图像质量评分均最高,70keV单能量图、QC图及90、110、130 keV单能量图的CNR、图像评分均依次递减.结论 能谱CT 50keV单能量图像能显著提高脑血管CTA的图像质量,值得临床推广应用.

  4. Development of a multilayer mirror for high-intensity monochromatic x-ray using lab-based x-ray source.

    Science.gov (United States)

    Nguyen, Thanh-hai; Song, Seonggeun; Jung, Jin-Ho; Jeon, Insu

    2012-09-15

    A parabolic, multilayer x-ray mirror, which can be used with a general lab-based x-ray source, was designed and fabricated. A glass substrate for the mirror was fabricated. Its surface was determined by following the rotation of a parabolic curve and was polished precisely. On the substrate surface, six W/Al bilayers were deposited to form the multilayer mirror. The effects of the mirror on x-ray images were investigated based on the calculated modulation transfer function (MTF) and image intensity values. Higher MTF and intensity values of an x-ray image were obtained using the mirror.

  5. Computed tomography image using sub-terahertz waves generated from a high-T{sub c} superconducting intrinsic Josephson junction oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Kashiwagi, T., E-mail: kashiwagi@ims.tsukuba.ac.jp; Minami, H.; Kadowaki, K. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Division of Materials Science, Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Nakade, K.; Saiwai, Y.; Kitamura, T.; Watanabe, C.; Ishida, K.; Sekimoto, S.; Asanuma, K.; Yasui, T.; Shibano, Y. [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba (Japan); Tsujimoto, M. [Department of Electronic Science and Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Yamamoto, T. [Wide Bandgap Materials Group, Optical and Electronic Materials Unit, Environment and Energy Materials Division, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Marković, B. [Faculty of Sciences, University of Montenegro, George Washington Str., 81000 Podgorica (Montenegro); Mirković, J. [Faculty of Science, University of Montenegro, and CETI, Put Radomira Ivanovica, 81000 Podgorica (Montenegro); Klemm, R. A. [Department of Physics, University of Central Florida, 4000 Central Florida Blvd., Orlando, Florida 32816-2385 (United States)

    2014-02-24

    A computed tomography (CT) imaging system using monochromatic sub-terahertz coherent electromagnetic waves generated from a device constructed from the intrinsic Josephson junctions in a single crystalline mesa structure of the high-T{sub c} superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+δ} was developed and tested on three samples: Standing metallic rods supported by styrofoam, a dried plant (heart pea) containing seeds, and a plastic doll inside an egg shell. The images obtained strongly suggest that this CT imaging system may be useful for a variety of practical applications.

  6. Broadband Phase Retrieval for Image-Based Wavefront Sensing

    Science.gov (United States)

    Dean, Bruce H.

    2007-01-01

    A focus-diverse phase-retrieval algorithm has been shown to perform adequately for the purpose of image-based wavefront sensing when (1) broadband light (typically spanning the visible spectrum) is used in forming the images by use of an optical system under test and (2) the assumption of monochromaticity is applied to the broadband image data. Heretofore, it had been assumed that in order to obtain adequate performance, it is necessary to use narrowband or monochromatic light. Some background information, including definitions of terms and a brief description of pertinent aspects of image-based phase retrieval, is prerequisite to a meaningful summary of the present development. Phase retrieval is a general term used in optics to denote estimation of optical imperfections or aberrations of an optical system under test. The term image-based wavefront sensing refers to a general class of algorithms that recover optical phase information, and phase-retrieval algorithms constitute a subset of this class. In phase retrieval, one utilizes the measured response of the optical system under test to produce a phase estimate. The optical response of the system is defined as the image of a point-source object, which could be a star or a laboratory point source. The phase-retrieval problem is characterized as image-based in the sense that a charge-coupled-device camera, preferably of scientific imaging quality, is used to collect image data where the optical system would normally form an image. In a variant of phase retrieval, denoted phase-diverse phase retrieval [which can include focus-diverse phase retrieval (in which various defocus planes are used)], an additional known aberration (or an equivalent diversity function) is superimposed as an aid in estimating unknown aberrations by use of an image-based wavefront-sensing algorithm. Image-based phase-retrieval differs from such other wavefront-sensing methods, such as interferometry, shearing interferometry, curvature

  7. CHARACTERIZATION OF DIESEL SPRAY IMAGES USING THE LOGARITHMIC IMAGE PROCESSING FRAMEWORK

    Directory of Open Access Journals (Sweden)

    Cecile Petit

    2011-05-01

    Full Text Available The increasing levels of emission standards in Diesel Engines require a detailed understanding, combustion and after treatment. This paper focuses on the spray development as one key parameter in the mixture preparation. The presentation of a methodology to differentiate the internal symmetry of spray images taken under different environmental conditions is presented. In a first step, a preprocessing is performed, then an image re-centering is made using the logarithmic average, afterwards different symmetry axes based on grey levels or on the plume boundary are calculated and, finally, the logarithmic distance characterizing the spray plume internal symmetry is computed. This distance gives more importance to the high grey level pixels, so using our optical setup, it characterizes the liquid continuous core symmetry. The methodology relies on the logarithmic image processing framework, providing a set of specific algebraic and functional operations to analyze images. This paper is an application of the logarithmic image processing framework on Diesel spray characterization. This is a step further in the quantitative diesel spray characterization by means of image analysis. The presented method can be applied to Diesel sprays illuminated with polychromatic or monochromatic light, under atmospheric or pressurized conditions.

  8. An evaluation of three commercially available metal artifact reduction methods for CT imaging

    Science.gov (United States)

    Huang, Jessie Y.; Kerns, James R.; Nute, Jessica L.; Liu, Xinming; Balter, Peter A.; Stingo, Francesco C.; Followill, David S.; Mirkovic, Dragan; Howell, Rebecca M.; Kry, Stephen F.

    2015-02-01

    Three commercial metal artifact reduction methods were evaluated for use in computed tomography (CT) imaging in the presence of clinically realistic metal implants: Philips O-MAR, GE’s monochromatic gemstone spectral imaging (GSI) using dual-energy CT, and GSI monochromatic imaging with metal artifact reduction software applied (MARs). Each method was evaluated according to CT number accuracy, metal size accuracy, and streak artifact severity reduction by using several phantoms, including three anthropomorphic phantoms containing metal implants (hip prosthesis, dental fillings and spinal fixation rods). All three methods showed varying degrees of success for the hip prosthesis and spinal fixation rod cases, while none were particularly beneficial for dental artifacts. Limitations of the methods were also observed. MARs underestimated the size of metal implants and introduced new artifacts in imaging planes beyond the metal implant when applied to dental artifacts, and both the O-MAR and MARs algorithms induced artifacts for spinal fixation rods in a thoracic phantom. Our findings suggest that all three artifact mitigation methods may benefit patients with metal implants, though they should be used with caution in certain scenarios.

  9. X-ray tube-based diffraction enhanced imaging prototype images of full-thickness breast specimens: reader study evaluation

    Science.gov (United States)

    Faulconer, L. S.; Parham, C.; Connor, D. J.; Koomen, M.; Kuzmiak, C.; Pavic, D.; Livasy, C. A.; Kim, E.; Zeng, D.; Cole, E. B.; Zhong, Z.; Pisano, E. D.

    2009-02-01

    Conventional mammographic image contrast is derived from x-ray absorption, resulting in breast structure visualization due to density gradients that attenuate radiation without distinction between transmitted and scattered or refracted x-rays. This leads to image blurring and contrast reduction, hindering the early detection of small or otherwise occult cancers. Diffraction enhanced imaging (DEI) allows for dramatically increased contrast with decreased radiation dose compared to conventional mammographic imaging due to monochromatic x-rays, its unique refraction-based contrast mechanism and excellent scatter rejection. However, a lingering drawback to the clinical translation of DEI has been the requirement for synchrotron radiation. Our laboratory developed a DEI prototype (DEI-PR) utilizing a readily available Tungsten xray tube source and traditional DEI crystal optics, providing soft tissue images at 60keV. To demonstrate the clinical utility of our DEI-PR, we acquired images of full-thickness human breast tissue specimens on synchrotron-based DEI, DEI-PR and digital mammography systems. A reader study was designed to allow unbiased assessment of system performance when analyzing three systems with dissimilar imaging parameters and requiring analysis of images unfamiliar to radiologists. A panel of expert radiologists evaluated lesion feature visibility and histopathology correlation after receiving training on the interpretation of refraction contrast mammographic images. Preliminary data analysis suggests that our DEI system performed roughly equivalently with the traditional DEI system, demonstrating a significant step toward clinical translation of this modality for breast cancer applications.

  10. 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.

  11. Photofission of {sup NAT} Pt by monochromatic and polarized photons in the quasi-deuteron region; Fotofissao da {sup NAT} Pt por fotons monocromaticos e polarizados na regiao do quase-deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Paiva, Eduardo de

    1992-01-01

    The measurement of the Nat Pt photofission yield at 69 MeV of effective average energy of the incident photon is made using a polarized and monochromatic photon beam from the LADON system of the National Laboratory of Frascati, Italy, produced by inverse Compton scattering of laser light by high energy electrons of the ADONE Accelerator and using as fission track solid detector the Makrofol, being the developing made by usual procedure. The experimental value of the nuclear fissionability is compared to a theoretical value obtained following a model at two stages: in the first, the photon energy is absorbed by a neutron-proton pair inducing to the nucleus excitation, and in the second the nucleus de-excites due to the competition between nucleon evaporation and fission. The effect of fast nucleon emission during the first stage and the successive evaporation of neutrons in the second stage are considered. 40 refs, 12 figs, 9 tabs.

  12. Auger-electron spectra of F{sub 3}SiCH{sub 2}CH{sub 2}Si(CH{sub 3}){sub 3} obtained by using monochromatized synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Nagaoka, Shin-ichi, E-mail: nagaoka@ehimegw.dpc.ehime-u.ac.j [Department of Chemistry, Faculty of Science, Ehime University, Matsuyama 790-8577 (Japan); Nitta, Akiko [Department of Chemistry, Faculty of Science, Ehime University, Matsuyama 790-8577 (Japan); Tamenori, Yusuke [Japan Synchrotron Radiation Research Institute/SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun 679-5198 (Japan); Fukuzawa, Hironobu; Ueda, Kiyoshi [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577 (Japan); Takahashi, Osamu [Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526 (Japan); Kakiuchi, Takuhiro [Department of Chemistry, Faculty of Science, Ehime University, Matsuyama 790-8577 (Japan); Institute of Materials Structure Science (IMSS), High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba 305-0801 (Japan); Kitajima, Yoshinori; Mase, Kazuhiko; Suzuki, Isao H. [Institute of Materials Structure Science (IMSS), High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba 305-0801 (Japan)

    2009-12-15

    A study on Auger-electron spectra of F{sub 3}SiCH{sub 2}CH{sub 2}Si(CH{sub 3}){sub 3} was performed by using monochromatized synchrotron radiation. The normal Si:L{sub 23}VV Auger-electron spectrum was measured in the vapor phase and characterized through the ab initio molecular orbital calculation. The cascade Si:L{sub 23}VV Auger-electron spectra were also obtained by L{sub 23}-holes creation through Si:KL{sub 23}L{sub 23} Auger transitions after Si:1s photoexcitation in the vapor phase or its photoelectron emission in the condensed phase. Further the C:KVV and F:KVV Auger-electron spectra were measured and discussed in comparison with those of some related molecules.

  13. Cellular resolution volumetric in vivo retinal imaging with adaptive optics–optical coherence tomography◊

    Science.gov (United States)

    Zawadzki, Robert J.; Choi, Stacey S.; Fuller, Alfred R.; Evans, Julia W.; Hamann, Bernd; Werner, John S.

    2009-01-01

    Ultrahigh-resolution adaptive optics–optical coherence tomography (UHR-AO-OCT) instrumentation allowing monochromatic and chromatic aberration correction was used for volumetric in vivo retinal imaging of various retinal structures including the macula and optic nerve head (ONH). Novel visualization methods that simplify AO-OCT data viewing are presented, and include co-registration of AO-OCT volumes with fundus photography and stitching of multiple AO-OCT sub-volumes to create a large field of view (FOV) high-resolution volume. Additionally, we explored the utility of Interactive Science Publishing by linking all presented AO-OCT datasets with the OSA ISP software. PMID:19259248

  14. Cellular resolution volumetric in vivo retinal imaging with adaptive optics-optical coherence tomography.

    Science.gov (United States)

    Zawadzki, Robert J; Choi, Stacey S; Fuller, Alfred R; Evans, Julia W; Hamann, Bernd; Werner, John S

    2009-03-02

    Ultrahigh-resolution adaptive optics-optical coherence tomography (UHR-AO-OCT) instrumentation allowing monochromatic and chromatic aberration correction was used for volumetric in vivo retinal imaging of various retinal structures including the macula and optic nerve head (ONH). Novel visualization methods that simplify AO-OCT data viewing are presented, and include co-registration of AO-OCT volumes with fundus photography and stitching of multiple AO-OCT sub-volumes to create a large field of view (FOV) high-resolution volume. Additionally, we explored the utility of Interactive Science Publishing by linking all presented AO-OCT datasets with the OSA ISP software.

  15. The structure and properties of color spaces and the representation of color images

    CERN Document Server

    Dubois, Eric

    2009-01-01

    This lecture describes the author's approach to the representation of color spaces and their use for color image processing. The lecture starts with a precise formulation of the space of physical stimuli (light). The model includes both continuous spectra and monochromatic spectra in the form of Dirac deltas. The spectral densities are considered to be functions of a continuous wavelength variable. This leads into the formulation of color space as a three-dimensional vector space, with all the associated structure. The approach is to start with the axioms of color matching for normal human vie

  16. Cathodoluminescence and Photoemission of Doped Lithium Tetraborate

    Science.gov (United States)

    2011-03-01

    41 The Photoemission Spectroscopy System .....................................................................43 Source ...Page 1. Measured and Standard Wavelengths for the non VUV system ......................................... 53 2. Mean Gaussian...explored. Neutron detection has the advantages of low natural background count, few neutron sources in normal commerce operations, and different

  17. Depth-Resolved Cathodoluminescence of Thorium Dioxide

    Science.gov (United States)

    2013-03-01

    saw. The cut samples were also polished with a series of diamond pastes to produce optically flat single-crystal wafers approximately 0.25 mm...to temperature variance, observe the evidence of a bump in the higher energy side of the 52 K and 77 K spectra. 62 Figure 39. Post-TOF

  18. Dual energy CT: New horizon in medical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Hyun Woo [Dept. of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Goo, Jin Mo [Dept. of Radiology, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2017-08-01

    Dual-energy CT has remained underutilized over the past decade probably due to a cumbersome workflow issue and current technical limitations. Clinical radiologists should be made aware of the potential clinical benefits of dual-energy CT over single-energy CT. To accomplish this aim, the basic principle, current acquisition methods with advantages and disadvantages, and various material-specific imaging methods as clinical applications of dual-energy CT should be addressed in detail. Current dual-energy CT acquisition methods include dual tubes with or without beam filtration, rapid voltage switching, dual-layer detector, split filter technique, and sequential scanning. Dual-energy material-specific imaging methods include virtual monoenergetic or monochromatic imaging, effective atomic number map, virtual non-contrast or unenhanced imaging, virtual non-calcium imaging, iodine map, inhaled xenon map, uric acid imaging, automatic bone removal, and lung vessels analysis. In this review, we focus on dual-energy CT imaging including related issues of radiation exposure to patients, scanning and post-processing options, and potential clinical benefits mainly to improve the understanding of clinical radiologists and thus, expand the clinical use of dual-energy CT; in addition, we briefly describe the current technical limitations of dual-energy CT and the current developments of photon-counting detector.

  19. Dual-Energy CT: New Horizon in Medical Imaging.

    Science.gov (United States)

    Goo, Hyun Woo; Goo, Jin Mo

    2017-01-01

    Dual-energy CT has remained underutilized over the past decade probably due to a cumbersome workflow issue and current technical limitations. Clinical radiologists should be made aware of the potential clinical benefits of dual-energy CT over single-energy CT. To accomplish this aim, the basic principle, current acquisition methods with advantages and disadvantages, and various material-specific imaging methods as clinical applications of dual-energy CT should be addressed in detail. Current dual-energy CT acquisition methods include dual tubes with or without beam filtration, rapid voltage switching, dual-layer detector, split filter technique, and sequential scanning. Dual-energy material-specific imaging methods include virtual monoenergetic or monochromatic imaging, effective atomic number map, virtual non-contrast or unenhanced imaging, virtual non-calcium imaging, iodine map, inhaled xenon map, uric acid imaging, automatic bone removal, and lung vessels analysis. In this review, we focus on dual-energy CT imaging including related issues of radiation exposure to patients, scanning and post-processing options, and potential clinical benefits mainly to improve the understanding of clinical radiologists and thus, expand the clinical use of dual-energy CT; in addition, we briefly describe the current technical limitations of dual-energy CT and the current developments of photon-counting detector.

  20. High dynamic range imaging for fringe projection profilometry with single-shot raw data of the color camera

    Science.gov (United States)

    Yin, Yongkai; Cai, Zewei; Jiang, Hao; Meng, Xiangfeng; Xi, Jiangtao; Peng, Xiang

    2017-02-01

    It is a challenging issue to get satisfied results in terms of 3D imaging for shiny surface with fringe projection profilometry (FPP), as the wide variation of surface reflectance for shiny surface will lead to bad exposure, which requires the high dynamic range imaging (HDRI) technique. HDRI with monochromatic illumination and single-shot raw data of the color camera is presented in this paper. From the single-shot raw data, 4 monochrome sub-images corresponding to R, G, G and B channels can be separated respectively. After the attenuation ratios between R&G, G&B channels are calibrated, an image with higher dynamic range can be synthesized with the 4 sub-images, which can help to avoid the impact of bad exposure and improve the accuracy of phase calculation. Experiments demonstrate the validity of proposed method for shiny surface.

  1. Determination of the optimal energy level in spectral CT imaging for displaying abdominal vessels in pediatric patients

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Di, E-mail: hudi0415@163.com [Beijing Children' s Hospital, Capital Medical University, Imaging Center, No. 56, Nanlishi Road, Xicheng District, Beijing 100045 (China); Yu, Tong, E-mail: hemophilia@126.com [Beijing Children' s Hospital, Capital Medical University, Imaging Center, No. 56, Nanlishi Road, Xicheng District, Beijing 100045 (China); Duan, Xiaomin, E-mail: potatocat@yeah.net [Beijing Children' s Hospital, Capital Medical University, Imaging Center, No. 56, Nanlishi Road, Xicheng District, Beijing 100045 (China); Peng, Yun, E-mail: ppengyun@yahoo.com [Beijing Children' s Hospital, Capital Medical University, Imaging Center, No. 56, Nanlishi Road, Xicheng District, Beijing 100045 (China); Zhai, Renyou, E-mail: zhairenyou@163.com [Beijing Chaoyang Hospital, Capital Medical University, Imaging Center, No. 8, Gongti South Road, Chaoyang District, Beijing 100020 (China)

    2014-03-15

    Purpose: To determine the optimal energy level in contrast-enhanced spectral CT imaging for displaying abdominal vessels in pediatric patients. Materials and methods: This retrospective study was institutional review board approved. 15 children (8 males and 7 females, age range, 6–15 years, mean age 10.1 ± 3.1 years) underwent contrast-enhanced spectral CT imaging for diagnosing solid tumors in abdomen and pelvic areas were included. A single contrast-enhanced scan was performed using a dual energy spectral CT mode with a new split contrast injection scheme (iodixanol at 1–1.5 ml/kg dose. 2/3 first, 1/3 at 7–15 s after the first injection). 101 sets of monochromatic images with photon energies of 40–140 keV with 1 keV interval were reconstructed. Contrast-noise-ratio (CNR) for hepatic portal or vein were generated and compared at every energy level to determine the optimal energy level to maximize CNR. 2 board-certified radiologists interpreted the selected image sets independently for image quality scores. Results: CT values and CNR for the vessels increased as photon energy decreased from 140 to 40 keV: (CT value: 48.29–570.12 HU, CNR: 0.08–14.90) in the abdominal aorta, (58.48–369.73 HU, 0.64–5.87) in the inferior vena cava, and (58.48–369.73 HU, 0.06–6.96) in the portal vein. Monochromatic images at 40–50 keV (average 42.0 ± 4.67 keV) could display vessels above three levels clearly, and with excellent image quality scores of 3.17 ± 0.58 (of 4) (k = 0.50). The CNR values at the optimal energy level were significantly higher than those at 70 keV, an average energy corresponding to the conventional 120 kVp for abdominal CT imaging. Conclusion: Spectral CT imaging provides a set of monochromatic images to optimize image quality and enhance vascular visibility, especially in the hepatic portal and vein systems. The best CNR for displaying abdominal vessels in children was obtained at 42 keV photon energy level.

  2. Cathodoluminescence investigation of relaxor-based ferroelectrics Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-0.3PbTiO{sub 3} (PMN-0.3PT) single-crystal

    Energy Technology Data Exchange (ETDEWEB)

    Ge Wanyin, E-mail: wanyinge@gmail.co [Ceramic Physics Laboratory and Research Institute for Nanoscience (RIN), Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, 606-8585 Kyoto (Japan); Zhu Wenliang [Ceramic Physics Laboratory and Research Institute for Nanoscience (RIN), Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, 606-8585 Kyoto (Japan); Pezzotti, Giuseppe, E-mail: pezzotti@kit.ac.j [Ceramic Physics Laboratory and Research Institute for Nanoscience (RIN), Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, 606-8585 Kyoto (Japan)

    2010-01-01

    Relaxor-based ferroelectric lead magnesium niobate-lead titanate Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-PbTiO{sub 3} (PMN-PT) possesses ultrahigh electromechanical coefficients near the morphotropic phase boundary (MPB). In this paper, the electro-stimulated emission characteristics of a [0 0 1]-oriented PMN-0.3PTsingle-crystal were studied using high resolution cathodoluminescence (CL) spectroscopy at room temperature. Four luminescence bands were observed in the range of 200-900 nm and they were assigned to polaron, nanometre cluster emission, interband emission and structure-related emission. Besides, it was found that the residual stress field ahead of a crack tip of a Vickers indentation had a considerable influence on these luminescence bands. The relationship between the intensities of CL bands and the residual stress field has been investigated and discussed in this paper.

  3. Polychromatic phase contrast imaging as a basic step towards a widespread application of the technique

    Science.gov (United States)

    Olivo, A.; Speller, R.

    2007-10-01

    Phase contrast imaging (PCI) is probably the most exciting amongst emerging X-ray imaging techniques, as it has the potential to remove some of the main limitations of conventional radiology. As a consequence, significant effort is currently directed towards developing the technique for the first clinical implementations. In recent years, PCI has been widely experimented, but its use has been mainly restricted to synchrotron radiation (SR) facilities. Source-related limitations are in fact the most relevant in this context, and the fact that most phase techniques require monochromatic radiation makes these limitations even more severe. Amongst the different techniques, free-space propagation is the most suited to a polychromatic implementation. A detailed simulation, based on Fresnel/Kirchoff diffraction integrals, was devised to describe this imaging modality. This simulation accounts for source dimensions, beam spectrum and divergence and detector point spread function, and can thus be applied to any X-ray imaging system. In particular, by accepting these parameters as input, along with ones describing the sample, the model can be used to optimize the geometry of the set-up, i.e. to assess the source-to-sample and sample-to-detector distances that maximize feature detection. The simulation was validated experimentally by acquiring a range of images of different samples with a laboratory X-ray source. Good agreement was found between simulated and experimental data in all cases. In order to maximize the generality of the results, all acquisitions were carried out using a polychromatic source and an energy-resolving detector. This effectively allowed the recording of a range of monochromatic and polychromatic images in a single acquisition, as an assortment of the former can be created by integrating different parts of the acquired spectra. The most notable result obtained in this study is that in most practical cases polychromatic PCI can provide the same image

  4. A multispectral testbed for cardiovascular sensing using imaging photoplethysmography

    Science.gov (United States)

    Blackford, Ethan B.; Estepp, Justin R.

    2017-02-01

    Imaging photoplethysmography uses image sensors to measure changes in light absorption resulting from skin microvascular blood volume pulsations throughout the cardiac cycle. Imaging photoplethysmography has been demonstrated as an effective, non-contact means of assessing pulse rate, pulse rate variability, and respiration rate. Other potential uses include measuring spatial blood perfusion, oxygenation, and flow dynamics. Herein we demonstrate the development of a multispectral testbed for imaging photoplethysmography consisting of 12 monochromatic, 120fps imagers with 50nm, bandpass filters distributed from 400-750nm and contained in a 3D-printed, 4x3 grid housing mounted on a tripod positioned orthogonal to the subject. A co-located dual-CCD RGB/near-infrared imager records conventional RGB and NIR images expanding the spectral window recorded. After image registration, a multispectral image cube of the 13, partially overlapping bands is created. A spectrometer records high (spectral) resolution data from the participant's right cheek using a collimating lens attached to the measurement fiber. In addition, a spatial array of 5 RGB imagers placed at 0°, +/-20° and +/-40° positions with respect to the subject is employed for motion and spatial robustness. All imagers are synchronized by a hardware trigger source synchronized with a reference, physiological measurement device recording the subject's electrocardiography, bilateral fingertip and/or ear lobe photoplethysmography, bilateral galvanic skin response, and respiration signals. The development of the testbed and pilot data is presented. A full-scale evaluation of the spectral components of the imaging photoplethysmographic signal, optimization of iPPG SNR, and spatial perfusion and blood flow dynamics is currently underway.

  5. Hard X-ray Microscopic Imaging Of Human Breast Tissues

    Science.gov (United States)

    Park, Sung H.; Kim, Hong T.; Kim, Jong K.; Jheon, Sang H.; Youn, Hwa S.

    2007-01-01

    X-ray microscopy with synchrotron radiation will be a useful tool for innovation of x-ray imaging in clinical and laboratory settings. It helps us observe detailed internal structure of material samples non-invasively in air. And, it also has the potential to solve some tough problems of conventional breast imaging if it could evaluate various conditions of breast tissue effectively. A new hard x-ray microscope with a spatial resolution better than 100 nm was installed at Pohang Light Source, a third generation synchrotron radiation facility in Pohang, Korea. The x-ray energy was set at 6.95 keV, and the x-ray beam was monochromatized by W/B4C monochromator. Condenser and objective zone plates were used as x-ray lenses. Zernike phase plate next to condenser zone plate was introduced for improved contrast imaging. The image of a sample was magnified 30 times by objective zone plate and 20 times by microscope objective, respectively. After additional 10 times digital magnification, the total magnifying power was up to 6000 times in the end. Phase contrast synchrotron images of 10-μm-thick female breast tissue of the normal, fibroadenoma, fibrocystic change and carcinoma cases were obtained. By phase contrast imaging, hard x-rays enable us to observe many structures of breast tissue without sample preparations such as staining or fixation.

  6. Visualization of pigment distributions in paintings using synchrotron K-edge imaging

    Energy Technology Data Exchange (ETDEWEB)

    Krug, K.; Dik, J. [TU Delft, Department of Materials Science and Engineering, Delft (Netherlands); Leeuw, M. [Atelier for Restoration and Research of Paintings, The Hague (Netherlands); Whitson, A. den [L3 Communications, Woburn, MA (United States); Tortora, J. [JK Consulting, Sudbury, MA (United States); Coan, P.; Nemoz, C.; Bravin, A. [European Synchrotron Radiation Facility, Grenoble (France)

    2006-05-15

    X-ray radiography plays an important role in the study of artworks and archaeological artifacts. The internal structure of objects provides information on genesis, authenticity, painting technique, material condition and conservation history. Transmission radiography, however, does not provide information on the exact elemental composition of objects and heavy metal layers can shadow or obscure the ones including lighter elements. This paper presents the first application of synchrotron-based K-edge absorption imaging applied to paintings. Using highly monochromatic radiation, K-edge imaging is used to obtain elemental distribution images over large areas. Such elemental maps visualize the distribution of an individual pigment throughout the paint stratigraphy. This provides color information on hidden paint layers, which is of great relevance to art historians and painting conservators. The main advantage is the quick data acquisition time and the sensitivity to elements throughout the entire paint stratigraphy. The examination of a test painting is shown and further instrumental developments are discussed. (orig.)

  7. BIGRE: a low cross-talk integral field unit tailored for extrasolar planets imaging spectroscopy

    CERN Document Server

    Antichi, Jacopo; Gratton, Raffaele G; Mesa, Dino; Claudi, Riccardo U; Giro, Enrico; Boccaletti, Anthony; Mouillet, David; Puget, Pascal; Beuzit, Jean-Luc

    2009-01-01

    Integral field spectroscopy (IFS) represents a powerful technique for the detection and characterization of extrasolar planets through high contrast imaging, since it allows to obtain simultaneously a large number of monochromatic images. These can be used to calibrate and then to reduce the impact of speckles, once their chromatic dependence is taken into account. The main concern in designing integral field spectrographs for high contrast imaging is the impact of the diffraction effects and the non-common path aberrations together with an efficient use of the detector pixels. We focus our attention on integral field spectrographs based on lenslet-arrays, discussing the main features of these designs: the conditions of appropriate spatial and spectral sampling of the resulting spectrograph's slit functions and their related cross-talk terms when the system works at the diffraction limit. We present a new scheme for the integral field unit (IFU) based on a dual-lenslet device (BIGRE), that solves some of the ...

  8. Influence of partial coherence on analyzer-based imaging with asymmetric Bragg reflection.

    Science.gov (United States)

    Modregger, Peter; Lübbert, Daniel; Schäfer, Peter; Richter, Jane; Köhler, Rolf; Baumbach, Tilo

    2009-07-06

    Image magnification via twofold asymmetric Bragg reflection (a setup called the "Bragg Magnifier") is a recently established technique allowing to achieve both sub-micrometer spatial resolution and phase contrast in X-ray imaging. The present article extends a previously developed theoretical formalism to account for partially coherent illumination. At a typical synchrotron setup polychromatic illumination is identified as the main influence of partial coherence and the implications on imaging characteristics are analyzed by numerical simulations. We show that contrast decreases by about 50% when compared to the monochromatic case, while sub-micrometer spatial resolution is preserved. The theoretical formalism is experimentally verified by correctly describing the dispersive interaction of the two orthogonal magnifier crystals, an effect that has to be taken into account for precise data evaluation.

  9. The characteristic analysis of spectral image for cabbage leaves damaged by diamondback moth pests

    Science.gov (United States)

    Lin, Li-bo; Li, Hong-ning; Cao, Peng-fei; Qin, Feng; Yang, Shu-ming; Feng, Jie

    2015-02-01

    Cabbage growth and health diagnosis are important parts for cabbage fine planting, spectral imaging technology with the advantages of obtaining spectrum and space information of the target at the same time, which has become a research hotspot at home and abroad. The experiment measures the reflection spectrum at different stages using liquid crystal tunable filter (LCTF) and monochromatic CMOS camera composed of spectral imaging system for cabbage leaves damaged by diamondback moth pests, and analyzes its feature bands and the change of spectral parameters. The study shows that the feature bands of cabbage leaves damaged by diamondback moth pests have a tendency to blue light direction, the red edge towards blue shift, and red valley raising in spectral characteristic parameters, which have a good indication in diagnosing the extent of cabbage damaged by pests. Therefore, it has a unique advantage of monitoring the cabbage leaves damaged by diamondback moth pests by combinating feature bands and spectral characteristic parameters in spectral imaging technology.

  10. Measuring reflective-band imaging systems for performance prediction

    Science.gov (United States)

    Slonopas, Andre; Preece, Bradley L.; Haefner, David P.

    2017-05-01

    An objective performance of the reflective-band imaging systems is required in order to provide the warfighter with the right technology for a specific task. Various methods to measure and model performance in the visible (Vis) spectral regions have been proposed in the literature. This correspondence shows the influence of the spectral region averaging on the monochromatic modulation transfer function (MTF). This works unequivocally shows that the illumination source plays a crucial role in the accurate predictive analysis of the system performance. For accurate analysis the illumination sources need to be carefully considered for the atmospheric conditions. This work shows the possibility of using an LED configuration in the system performance analysis. Such configurations need rigorous calibration in order to become a valuable asset in system characterization.

  11. Two-dimensional pixel array image sensor for protein crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Beuville, E.; Beche, J.-F.; Cork, C. [and others

    1996-07-01

    A 2D pixel array image sensor module has been designed for time resolved Protein Crystallography. This smart pixels detector significantly enhances time resolved Laue Protein crystallography by two to three orders of magnitude compared to existing sensors like films or phosphor screens coupled to CCDs. The resolution in time and dynamic range of this type of detector will allow one to study the evolution of structural changes that occur within the protein as a function of time. This detector will also considerably accelerate data collection in static Laue or monochromatic crystallography and make better use of the intense beam delivered by synchrotron light sources. The event driven pixel array detectors, based on the column Architecture, can provide multiparameter information (energy discrimination, time), with sparse and frameless readout without significant dead time. The prototype module consists of a 16x16 pixel diode array bump-bonded to the integrated circuit. The detection area is 150x150 square microns.

  12. Photon activated therapy (PAT using monochromatic Synchrotron x-rays and iron oxide nanoparticles in a mouse tumor model: feasibility study of PAT for the treatment of superficial malignancy

    Directory of Open Access Journals (Sweden)

    Choi Gi-Hwan

    2012-10-01

    Full Text Available Abstract Background X-rays are known to interact with metallic nanoparticles, producing photoelectric species as radiosensitizing effects, and have been exploited in vivo mainly with gold nanoparticles. The purpose of this study was to investigate the potential of sensitizing effect of iron oxide nanoparticles for photon activated therapy. Methods X-rays photon activated therapy (PAT was studied by treating CT26 tumor cells and CT26 tumor-bearing mice loaded with 13-nm diameter FeO NP, and irradiating them at 7.1 keV near the Fe K-edge using synchrotron x-rays radiation. Survival of cells was determined by MTT assay, and tumor regression assay was performed for in vivo model experiment. The results of PAT treated groups were compared with x-rays alone control groups. Results A more significant reduction in viability and damage was observed in the FeO NP-treated irradiated cells, compared to the radiation alone group (p Conclusions An iron oxide nanoparticle enhanced therapeutic effect with relatively low tissue concentration of iron and 10 Gy of monochromatic X-rays. Since 7.1 keV X-rays is attenuated very sharply in the tissue, FeO NP-PAT may have promise as a potent treatment option for superficial malignancies in the skin, like chest wall recurrence of breast cancer.

  13. Experimental test of a newly developed single-moderator, multi-detector, directional neutron spectrometer in reference monochromatic fields from 144 keV to 16.5 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Bedogni, R., E-mail: roberto.bedogni@lnf.infn.it [INFN – LNF, via E. Fermi n. 40, 00044 Frascati (Roma) (Italy); Gómez-Ros, J.M. [INFN – LNF, via E. Fermi n. 40, 00044 Frascati (Roma) (Italy); CIEMAT, Av. Complutense 40, 28040 Madrid (Spain); Pola, A.; Bortot, D. [Politecnico di Milano, Dipartimento di Energia, via La Masa 34, 20156 Milano (Italy); INFN – Milano, Via Celoria 16, 20133 Milano (Italy); Gentile, A. [INFN – LNF, via E. Fermi n. 40, 00044 Frascati (Roma) (Italy); Introini, M.V. [Politecnico di Milano, Dipartimento di Energia, via La Masa 34, 20156 Milano (Italy); INFN – Milano, Via Celoria 16, 20133 Milano (Italy); Buonomo, B. [INFN – LNF, via E. Fermi n. 40, 00044 Frascati (Roma) (Italy); Lorenzoli, M. [Politecnico di Milano, Dipartimento di Energia, via La Masa 34, 20156 Milano (Italy); INFN – Milano, Via Celoria 16, 20133 Milano (Italy); Mazzitelli, M. [INFN – LNF, via E. Fermi n. 40, 00044 Frascati (Roma) (Italy); Sacco, D. [INFN – LNF, via E. Fermi n. 40, 00044 Frascati (Roma) (Italy); INAIL – DPIA, Via di Fontana Candida n.1, 00040 Monteporzio Catone (Italy)

    2015-05-11

    A new directional neutron spectrometer called CYSP (CYlindrical SPectrometer) was developed within the NESCOFI@BTF (2011–2013) collaboration. The device, composed by seven active thermal neutron detectors located along the axis of a cylindrical moderator, was designed to simultaneously respond from the thermal domain up to hundreds of MeV neutrons. The new spectrometer condenses the performance of the Bonner Sphere Spectrometer in a single moderator; thus requiring only one exposure to determine the whole spectrum. The CYSP response matrix, determined with MCNP, has been experimentally evaluated with monochromatic reference neutron fields from 144 keV to 16.5 MeV, plus a {sup 252}Cf source, available at NPL (Teddington, UK). The results of the experiment confirmed the correctness of the response matrix within an overall uncertainty of ±2.5%. The new active spectrometer CYSP offers an innovative option for real-time monitoring of directional neutron fields as those produced in neutron beam-lines.

  14. Trial to active SWD using artificial energy source. Use of monochromatic source wavelet; Jinko shingen wo mochiita SWD eno kokoromi. Tan`itsu shuhasu no shingen hakei no riyo

    Energy Technology Data Exchange (ETDEWEB)

    Tsuru, T.; Kozawa, T. [Japan National Oil Corp., Tokyo (Japan); Taniguchi, R. [Mitsubishi Electric Corp., Tokyo (Japan); Matsuhashi, K. [Matsuhashi Techno Research, Hiroshima (Japan); Nishikawa, N. [Fuji Research Institute Corp., Tokyo (Japan)

    1998-04-01

    Seismic while drilling (SWD) is an accurate and safe method for drilling, by which real-time information regarding bit location and bedding boundary below the bit can be predicted by using elastic wave during drilling of rocks in a borehole. However, the signal level is rather low compared with the noise generated from the rig during drilling, resulting in the deteriorated data quality. Since the impact resiliency is small in soft beds, it is difficult to obtain good data due to the small energy of seismic wave propagating along drilling pipe. In order to overcome these problems, active SWD method using artificial seismic source has been developed. This method provides stable low-frequency seismic wave with large energy by the artificial seismic source adopting spring-mass system resonance method. Although the seismic source wave is monochromatic, the direct wave can be sufficiently analyzed and the bit location can be detected on the time profile of seismic prospecting. Protection of borehole damage during dropping of the equipment, energy propagation efficiency in the beds, and analysis of reflected wave are future problems. 11 refs., 6 figs., 4 tabs.

  15. The Research on the Non-monochromatic Lighting on Visibility of Michelson Interference Based on Matlab%基于MATLAB方法的非单色光迈克尔逊干涉研究

    Institute of Scientific and Technical Information of China (English)

    李芳菊

    2012-01-01

    从光的干涉理论出发,分析了光源的非单色性对迈克尔逊等倾干涉条纹可见度的影响,并利用Matlab对等倾干涉条纹可见度进行了数值模拟和实验模拟,用直观的可视化图像将抽象的时间相干性理论形象化,同时对迈克尔逊干涉仪的理论教学和实践应用都有一定的指导意义.%According to the basic theory of optical interference,the changes of visibility of Michelson interferometer fringe was analyzed because of non-monochromatic light,which can realize the simulation of Michelson interferometer experiment.These computer pictures make the Abstract concept of temporal coherence of light visual.It also makes up for the drawback that theoretical teaching is divorced from practice.

  16. TESIS experiment on EUV imaging spectroscopy of the Sun

    Science.gov (United States)

    Kuzin, S. V.; Bogachev, S. A.; Zhitnik, I. A.; Pertsov, A. A.; Ignatiev, A. P.; Mitrofanov, A. M.; Slemzin, V. A.; Shestov, S. V.; Sukhodrev, N. K.; Bugaenko, O. I.

    2009-03-01

    TESIS is a set of solar imaging instruments in development by the Lebedev Physical Institute of the Russian Academy of Science, to be launched aboard the Russian spacecraft CORONAS-PHOTON in December 2008. The main goal of TESIS is to provide complex observations of solar active phenomena from the transition region to the inner and outer solar corona with high spatial, spectral and temporal resolution in the EUV and Soft X-ray spectral bands. TESIS includes five unique space instruments: the MgXII Imaging Spectroheliometer (MISH) with spherical bent crystal mirror, for observations of the Sun in the monochromatic MgXII 8.42 Å line; the EUV Spectoheliometer (EUSH) with grazing incidence difraction grating, for the registration of the full solar disc in monochromatic lines of the spectral band 280-330 Å; two Full-disk EUV Telescopes (FET) with multilayer mirrors covering the band 130-136 and 290-320 Å; and the Solar EUV Coronagraph (SEC), based on the Ritchey-Chretien scheme, to observe the inner and outer solar corona from 0.2 to 4 solar radii in spectral band 290-320 Å. TESIS experiment will start at the rising phase of the 24th cycle of solar activity. With the advanced capabilities of its instruments, TESIS will help better understand the physics of solar flares and high-energy phenomena and provide new data on parameters of solar plasma in the temperature range 10-10K. This paper gives a brief description of the experiment, its equipment, and its scientific objectives.

  17. Body Image

    Science.gov (United States)

    ... About Us Contact Us Text size | Print | Body Image Developing a positive body image and a healthy mental attitude is crucial to ... on for tips to have a healthy body image. Topics About body image When you look in ...

  18. A multiple monochromatic X-ray imaging spectrometer based on flat Bragg mirror%基于布拉格反射镜的X射线多色单能成像谱仪

    Institute of Scientific and Technical Information of China (English)

    胡昕; 张继彦; 杨国洪; 刘慎业; 丁永坤

    2009-01-01

    报道了一种基于布拉格反射镜的多色单能成像谱仪研制工作,谱仪由针孔阵列、布拉格反射镜和CCD相机组成.大约有300个微孔的针孔阵列板置于布拉格镜前用于空间成像,通过布拉格反射镜的单色化,投射到CCD上的数百个小孔成像沿色散方向获得了能量分辨.经过图像处理,可以还原得到目标的多色单能二维成像.根据采用的布拉格分光元件和图像还原方法,谱仪的能量分辨达到了50-200(λ/△λ);针孔成像的空间分辨优于10 μm.同时还为该谱仪开发了专门的单能图像重建软件及图像数据后处理软件,可以在任意选择的窄能带内还原准单能图像.并重点介绍了该谱仪的优化设计、获得的技术指标以及专门研制的超短周期(2.5 nm)X射线W/B4C多层镜.

  19. Angle-resolved catholdoluminescence imaging polarimetry

    NARCIS (Netherlands)

    Osorio, C.I.; Coenen, T.; Brenny, B.J.M.; Polman, A.; Koenderink, A.F.

    2015-01-01

    Cathodoluminescence spectroscopy (CL) allows characterizing light emission in bulk and nanostructured materials and is a key tool in fields ranging from materials science to nanophotonics. Previously, CL measurements focused on the spectral content and angular distribution of emission, while the pol

  20. Feasibility study to demonstrate cardiac imaging using fast kVp switching dual-energy computed tomography: phantom study

    Science.gov (United States)

    Madhav, Priti; Imai, Yasuhiro; Narayanan, Suresh; Dutta, Sandeep; Chandra, Naveen; Hsieh, Jiang

    2012-03-01

    Dual-energy computed tomography is a novel imaging tool that has the potential to reduce beam hardening artifacts and enhance material separation over conventional imaging techniques. Dual-energy acquisitions can be performed by using a fast kVp technology to switch between acquiring adjacent projections at two distinct x-ray spectra (80 and 140 kVp). These datasets can be used to further compute material density and monochromatic images for better material separation and beam hardening reduction by virtue of the projection domain process. The purpose of this study was to evaluate the feasibility of using dual-energy in cardiac imaging for myocardial perfusion detection and coronary artery lumen visualization. Data was acquired on a heart phantom, which consisted of the chambers and aorta filled with Iodine density solution (500 HU @ 120 kVp), a defect region between the aorta and chamber (40 HU @ 120 kVp), two Iodinefilled vessels (400 HU @ 120 kVp) of different diameters with high attenuation (hydroxyapatite) plaques (HAP), and with a 30-cm water equivalent body ring around the phantom. Prospective ECG-gated single-energy and prospective ECG-gated dual-energy imaging was performed. Results showed that the generated monochromatic images had minimal beam hardening artifacts which improved the accuracy and detection of the myocardial defect region. Material density images were useful in differentiating and quantifying the actual size of the plaque and coronary artery lumen. Overall, this study shows that dual-energy cardiac imaging will be a valuable tool for cardiac applications.

  1. Image Coding Based on Address Vector Quantization.

    Science.gov (United States)

    Feng, Yushu

    Image coding is finding increased application in teleconferencing, archiving, and remote sensing. This thesis investigates the potential of Vector Quantization (VQ), a relatively new source coding technique, for compression of monochromatic and color images. Extensions of the Vector Quantization technique to the Address Vector Quantization method have been investigated. In Vector Quantization, the image data to be encoded are first processed to yield a set of vectors. A codeword from the codebook which best matches the input image vector is then selected. Compression is achieved by replacing the image vector with the index of the code-word which produced the best match, the index is sent to the channel. Reconstruction of the image is done by using a table lookup technique, where the label is simply used as an address for a table containing the representative vectors. A code-book of representative vectors (codewords) is generated using an iterative clustering algorithm such as K-means, or the generalized Lloyd algorithm. A review of different Vector Quantization techniques are given in chapter 1. Chapter 2 gives an overview of codebook design methods including the Kohonen neural network to design codebook. During the encoding process, the correlation of the address is considered and Address Vector Quantization is developed for color image and monochrome image coding. Address VQ which includes static and dynamic processes is introduced in chapter 3. In order to overcome the problems in Hierarchical VQ, Multi-layer Address Vector Quantization is proposed in chapter 4. This approach gives the same performance as that of the normal VQ scheme but the bit rate is about 1/2 to 1/3 as that of the normal VQ method. In chapter 5, a Dynamic Finite State VQ based on a probability transition matrix to select the best subcodebook to encode the image is developed. In chapter 6, a new adaptive vector quantization scheme, suitable for color video coding, called "A Self -Organizing

  2. Bystander Effects During Synchrotron Imaging Procedures?

    Science.gov (United States)

    Schültke, Elisabeth; Bewer, Brian; Wysokinski, Tomasz; Chapman, Dean; Nikkhah, Guido

    2010-07-01

    Using monochromatic beam and synchrotron phase-contrast technique at the biomedical beamline of the Italian synchrotron facility Elettra (SYRMEP), we have shown in a small animal model of malignant brain tumor that it is possible to obtain high-resolution images of very small tumors when they have developed from implanted tumor cells loaded with colloidal gold nanoparticles (GNP). All previous experiments were conducted in post-mortem samples. We have now designed a cell culture experiment to investigate the effects of synchrotron radiation with an energy and dose profile similar to that expected in our first in vivo imaging studies according to the protocol developed at SYRMEP. Materials and Methods: Culture flasks containing either gold-loaded or naïve C6 glioma cells were exposed to a dose of 0.5 Gy at 24 keV. The irradiated medium was aspirated and replaced with fresh growth medium. Twenty-four hours later this non-irradiated medium exposed to irradiated cells was aspirated, then added to non-irradiated C6 cells in order to investigate whether bystander effects are seen under the conditions of our image acquisition protocol. The irradiated medium was added to a number of other non-irradiated cell cultures. Cell counts were followed until 72 hrs after irradiation. Western blots were conducted with H2AX antibodies. This experiment was one of the first biomedical experiments conducted at BMIT, the new biomedical imaging and therapy beamline of the Canadian Light Source. Results: No significant differences in proliferation were seen between cells that were directly irradiated, exposed to irradiated medium or exposed to the non-irradiated 24-hr-medium from the irradiated cells. However, there was a tendency towards a higher number of double strand breaks in previously irradiated cells when they were exposed to non-irradiated medium that had been in contact with irradiated cells for 24 hrs.

  3. Summary of Quantitative Interpretation of Image Far Ultraviolet Auroral Data

    Science.gov (United States)

    Frey, H. U.; Immel, T. J.; Mende, S. B.; Gerard, J.-C.; Hubert, B.; Habraken, S.; Span, J.; Gladstone, G. R.; Bisikalo, D. V.; Shematovich, V. I.; hide

    2002-01-01

    Direct imaging of the magnetosphere by instruments on the IMAGE spacecraft is supplemented by simultaneous observations of the global aurora in three far ultraviolet (FUV) wavelength bands. The purpose of the multi-wavelength imaging is to study the global auroral particle and energy input from thc magnetosphere into the atmosphere. This paper describes provides the method for quantitative interpretation of FUV measurements. The Wide-Band Imaging Camera (WIC) provides broad band ultraviolet images of the aurora with maximum spatial and temporal resolution by imaging the nitrogen lines and bands between 140 and 180 nm wavelength. The Spectrographic Imager (SI), a dual wavelength monochromatic instrument, images both Doppler-shifted Lyman alpha emissions produced by precipitating protons, in the SI-12 channel and OI 135.6 nm emissions in the SI-13 channel. From the SI-12 Doppler shifted Lyman alpha images it is possible to obtain the precipitating proton flux provided assumptions are made regarding the mean energy of the protons. Knowledge of the proton (flux and energy) component allows the calculation of the contribution produced by protons in the WIC and SI-13 instruments. Comparison of the corrected WIC and SI-13 signals provides a measure of the electron mean energy, which can then be used to determine the electron energy fluxun-. To accomplish this reliable modeling emission modeling and instrument calibrations are required. In-flight calibration using early-type stars was used to validate the pre-flight laboratory calibrations and determine long-term trends in sensitivity. In general, very reasonable agreement is found between in-situ measurements and remote quantitative determinations.

  4. Indexing Images.

    Science.gov (United States)

    Rasmussen, Edie M.

    1997-01-01

    Focuses on access to digital image collections by means of manual and automatic indexing. Contains six sections: (1) Studies of Image Systems and their Use; (2) Approaches to Indexing Images; (3) Image Attributes; (4) Concept-Based Indexing; (5) Content-Based Indexing; and (6) Browsing in Image Retrieval. Contains 105 references. (AEF)

  5. K-edge digital subtraction imaging based on a dichromatic and compact x-ray source

    Science.gov (United States)

    Sarnelli, A.; Taibi, A.; Tuffanelli, A.; Baldazzi, G.; Bollini, D.; Cabal Rodriguez, A. E.; Gombia, M.; Prino, F.; Ramello, L.; Tomassi, E.; Gambaccini, M.

    2004-07-01

    This work proposes a compact dichromatic imaging system for the application of the K-edge digital subtraction technique based on a conventional x-ray tube and a monochromator system. A quasi-monochromatic x-ray beam at the energy of iodine K-edge is produced by Bragg diffraction on a mosaic crystal. Two thin adjacent beams with energies that bracket the K-edge discontinuity are obtained from the diffracted beam by means of a proper collimation system. They are then detected using an array of Si detectors. A home-made phantom is used to study the image quality as a function of iodine concentration. Signal and signal-to-noise ratio analysis has also been performed. The results are compared with theoretical expectations.

  6. Focal length measurement of microlens-array by the clarity function of digital image

    Science.gov (United States)

    Zhu, Xianchang; Wu, Fan; Cao, Xuedong; Wu, Shibin; Zhang, Peng; Jing, Hongwei

    2012-10-01

    In this paper, a method for the focal length measurement of Microlens-array (MLA) is introduced. The measuring setup is composed by monochromatic, condenser, collimator, MLA, microscope and CCD sensor. An experiment was performed using a MLA whose focal length is about 8 mm and a GUI based on Matlab software was developed to analyze the image gathered at the vertex and the focus by the clarity of digital image processing technology. The measuring uncertainty of this method is about 0.8% and this method introduced in this paper can finish tens of microlens array measurement at a single shot. Compared with traditional technology for MLA measuring, this method not only has a preferable precision but also super efficiency.

  7. K-edge digital subtraction imaging based on a dichromatic and compact x-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Sarnelli, A [Dipartimento di Fisica dell' Universita di Ferrara and INFN Sezione di Ferrara, Via Paradiso 12, I-44100 Ferrara (Italy); Taibi, A [Dipartimento di Fisica dell' Universita di Ferrara and INFN Sezione di Ferrara, Via Paradiso 12, I-44100 Ferrara (Italy); Tuffanelli, A [Dipartimento di Fisica dell' Universita di Ferrara and INFN Sezione di Ferrara, Via Paradiso 12, I-44100 Ferrara (Italy); Baldazzi, G [Dipartimento di Fisica dell' Universita di Bologna and INFN Sezione di Bologna, Viale Berti Pichat 64/2, 40127 Bologna (Italy); Bollini, D [Dipartimento di Fisica dell' Universita di Bologna and INFN Sezione di Bologna, Viale Berti Pichat 64/2, 40127 Bologna (Italy); Rodriguez, A E Cabal [CAEDAN, Havana (Cuba); Gombia, M [Dipartimento di Fisica dell' Universita di Bologna and INFN Sezione di Bologna, Viale Berti Pichat 64/2, 40127 Bologna (Italy); Prino, F [Dipartimento di Scienze e Tecnologie Avanzate, Universita del Piemonte Orientale and INFN Sezione di Alessandria, C.so, Borsalino 54, I-15100 Alessandria (Italy); Ramello, L [Dipartimento di Scienze e Tecnologie Avanzate, Universita del Piemonte Orientale and INFN Sezione di Alessandria, C.so, Borsalino 54, I-15100 Alessandria (Italy); Tomassi, E [Dipartimento di Scienze e Tecnologie Avanzate, Universita del Piemonte Orientale and INFN Sezione di Alessandria, C.so, Borsalino 54, I-15100 Alessandria (Italy); Gambaccini, M [Dipartimento di Fisica dell' Universita di Ferrara and INFN Sezione di Ferrara, Via Paradiso 12, I-44100 Ferrara (Italy)

    2004-07-21

    This work proposes a compact dichromatic imaging system for the application of the K-edge digital subtraction technique based on a conventional x-ray tube and a monochromator system. A quasi-monochromatic x-ray beam at the energy of iodine K-edge is produced by Bragg diffraction on a mosaic crystal. Two thin adjacent beams with energies that bracket the K-edge discontinuity are obtained from the diffracted beam by means of a proper collimation system. They are then detected using an array of Si detectors. A home-made phantom is used to study the image quality as a function of iodine concentration. Signal and signal-to-noise ratio analysis has also been performed. The results are compared with theoretical expectations.

  8. Imaging spectrophotometry of ionized gas in NGC 1068. I - Kinematics of the narrow-line region

    Science.gov (United States)

    Cecil, Gerald; Bland, Jonathan; Tully, R. Brent

    1990-01-01

    The kinematics of collisionally excited forbidden N II 6548, 6583 across the inner 1 arcmin diameter of the nearby Seyfert galaxy NGC 1068 is mapped using an imaging Fabry-Perot interferometer and low-noise CCD. The stack of monochromatic images, which spatially resolved the high-velocity gas, was analyzed for kinematic and photometric content. Profiles agree well with previous long-slit work, and their complete spatial coverage makes it possible to constrain the gas volume distribution. It is found that the narrow-line region is distributed in a thick center-darkened, line-emitting cylinder that envelopes the collimated radio jet. Three distinct kinematic subsystems, of which the cylinder is composed, are discussed in detail. Detailed behavior of the emission-line profiles, at the few points in the NE quadrant with simple kinematics, argues that the ionized gas develops a significant component of motion perpendicular to the jet axis.

  9. High-Contrast Near-Infrared Imaging Polarimetry of the Protoplanetary Disk around RY Tau

    CERN Document Server

    Takami, Michihiro; Hashimoto, Jun; Kim, Hyosun; Wisnewski, John; Henning, Thomas; Grady, Carol A; Kandori, Ryo; Hodapp, Klaus W; Kudo, Tomoyuki; Kusakabe, Nobuhiko; Chou, Mei-Yin; Itoh, Yoichi; Momose, Munetake; Mayama, Satoshi; Currie, Thayne; Follette, Katherine B; Kwon, Jungmi; Abe, Lyu; Brandner, Wolfgang; Brandt, Timothy D; Carson, Joseph; Egner, Sebastian E; Feldt, Markus; Guyon, Olivier; Hayano, Yutaka; Hayashi, Masahiko; Hayashi, Saeko; Ishii, Miki; Iye, Masanori; Janson, Markus; Knapp, Gillian R; Kuzuhara, Masayuki; McElwain, Michael W; Matsuo, Taro; Miyama, Shoken; Morino, Jun-Ichi; Moro-Martin, Amaya; Nishimura, Tetsuo; Pyo, Tae-Soo; Serabyn, Eugene; Suto, Hiroshi; Suzuki, Ryuji; Takato, Naruhisa; Terada, Hiroshi; Thalmann, Christian; Tomono, Daigo; Turner, Edwin L; Watanabe, Makoto; Yamada, Toru; Takami, Hideki; Usuda, Tomonori; Tamura, Motohide

    2013-01-01

    We present near-infrared coronagraphic imaging polarimetry of RY Tau. The scattered light in the circumstellar environment was imaged at H-band at a high resolution (~0".05) for the first time, using Subaru-HiCIAO. The observed polarized intensity (PI) distribution shows a butterfly-like distribution of bright emission with an angular scale similar to the disk observed at millimeter wavelengths. This distribution is offset toward the blueshifted jet, indicating the presence of a geometrically thick disk or a remnant envelope, and therefore the earliest stage of the Class II evolutionary phase. We perform comparisons between the observed PI distribution and disk models with: (1) full radiative transfer code, using the spectral energy distribution (SED) to constrain the disk parameters; and (2) monochromatic simulations of scattered light which explore a wide range of parameters space to constrain the disk and dust parameters. We show that these models cannot consistently explain the observed PI distribution, S...

  10. Imaging of local temperature distributions in mesas of high-Tc superconducting terahertz sources

    Science.gov (United States)

    Tsujimoto, M.; Kambara, H.; Maeda, Y.; Yoshioka, Y.; Nakagawa, Y.; Kakeya, I.

    2014-12-01

    Stacks of intrinsic Josephson junctions in high-Tc superconductors are a promising source of intense, continuous, and monochromatic terahertz waves. In this paer, we establish a fluorescence-based temperature imaging system to directly image the surface temperature on a Bi2Sr2CaCu2O8+δ mesa sample. Intense terahertz emissions are observed in both high- and low-bias regimes, where the mesa voltage satisfies the cavity resonance condition. In the high- bias regime, the temperature distributions are shown to be inhomogeneous with a considerable temperature rise. In contrast, in the low-bias regime, the distributions are rather uniform and the local temperature is close to the bath temperature over the entire sample.

  11. High-speed 3D imaging using two-wavelength parallel-phase-shift interferometry.

    Science.gov (United States)

    Safrani, Avner; Abdulhalim, Ibrahim

    2015-10-15

    High-speed three dimensional imaging based on two-wavelength parallel-phase-shift interferometry is presented. The technique is demonstrated using a high-resolution polarization-based Linnik interferometer operating with three high-speed phase-masked CCD cameras and two quasi-monochromatic modulated light sources. The two light sources allow for phase unwrapping the single source wrapped phase so that relatively high step profiles having heights as large as 3.7 μm can be imaged in video rate with ±2  nm accuracy and repeatability. The technique is validated using a certified very large scale integration (VLSI) step standard followed by a demonstration from the semiconductor industry showing an integrated chip with 2.75 μm height copper micro pillars at different packing densities.

  12. High spatial resolution X-UV Fresnel zone plates imaging; Imagerie a haute resolution spatiale dans le domaine X-UV a l'aide de lentilles a zone de Fresnel

    Energy Technology Data Exchange (ETDEWEB)

    Pichet-Thomasset, M

    1999-07-01

    The goal of this work is to study the capabilities of imaging of Fresnel zone plates in the 1.5. and 2 keV X-ray range for the imaging of laser-produced plasmas. The diagnostic is composed of a Fresnel zone plate with good imaging capabilities and a multilayer mirror to select the spectral emission bandwidth of the plasma we want to study. This diagnostic was evaluated at the Centre d'Etudes de Limeil-Valenton experiments to study spatial resolution with this kind of X-ray source. The images we obtained showed that there is no geometric aberrations over an object field of several millimetre. Fresnen zone plates are often used for monochromatic biological objects imaging in the water window around 400 eV but they offer large prospects for laser produced plasma imaging. (author)

  13. Comparison between Digital Image Processing and Spectrophotometric Measurements Methods

    Directory of Open Access Journals (Sweden)

    Bogdan Adnan HAIFA

    2011-03-01

    Full Text Available Background: Spectrophotometer is a very common instrument in various scientific fields and gives accurate information about light absorbance and transmittance through materials using monochromatic light source. Though, devices used in spectrophotometry can be quite expensive, using components with high technical specifications and the procedure itself is time consuming. Regular digital image acquisition instruments like scanners and cameras on the other hand uses very cheap electronic components to record the information on 3 wide band channels (Red, Green, Blue. Purpose: This paper studies the possibility of correlating the measurements from the spectrophotometer with raw data from digital image acquisition instruments. Materials and Methods: Because the results will be used in protein electrophoresis, we prepared o set of plates with blood serum in different dilutions, stained with Coomassie Brilliant Blue. The absorbance of the resulting plates has been measured using a spectrophotometer and after that, the plates were scanned with a regular office scanner. The digital image was converted in different color spaces (gray scale, RGB, HSV, HSL, CIEXYZ and CIELAB using custom developed software in C++. We statistically measured the correlation coefficient of different parameters from the color space with the absorption measured with the spectrophotometer. Results and Discussion: The findings of this work show that a consumer digital scanner can be used as a fast and inexpensive alternative to spectrophotometers. This offers the possibility of using scanned images of protein electrophoresis to make quantitative estimations regarding the proteinogram.

  14. Multiplexed Imaging of Trace Residues in a Single Latent Fingerprint.

    Science.gov (United States)

    Zhang, Yuyan; Zhou, Wen; Xue, Yang; Yang, Jie; Liu, Dingbin

    2016-12-20

    The development of highly sensitive, selective, nondestructive, and multiplexed imaging modalities is essential for latent fingerprint (LFP) identification and fingerprint residues detection. Herein, we present a versatile strategy to identify LFPs and to probe the multiple trace residues in a single LFP simultaneously. With the purpose of achieving high sensitivity, we for the first time introduced a polydopamine (PDA)-triggered Au growth method to prepare superbright and multiplex surface-enhanced Raman scattering (SERS) tags, which were endowed with high selectivity by conjugating with specific antibodies. In combination with a rapid Raman mapping technique, the sensitivity of the SERS probes was down to picogram scale and all the three levels of LFP features can be clearly seen. More significantly, the multiplexed imaging of diverse residues in a single LFP provides more accurate information than that using monochromatic imaging of individuals alone. The high analytical figures of merit enable this approach great promise for use in the fields ranging from chemical detection to molecular imaging.

  15. Imaging Multispettrale low-cost con filtri interferenziali

    Directory of Open Access Journals (Sweden)

    Antonio Cosentino

    2015-08-01

    Full Text Available Multispectral imaging systems are used in art examination in order to mapand identify pigments and binders as well as retouches. A monochromaticcamera (CCD or InGaAs is combined with an appropriate wavelength selectionsystem, simple as a set of interferential filters or powerful but expensive asliquid-crystal tunable filters. A variable number of spectral images of a sceneare then acquired and stacked into a reflectance imaging cube to be used toreconstruct reflectance spectra from each of their pixel.This work presents an affordable and simple multispectral imaging systemcomposed of a monochromatic CCD camera and a set of only 12 interferentialfilters. The system was tested on a mock-up painting realized with traditionaland modern pigments and also on a late 1800 authentic oil painting. Thissystem is of particular interest for the cultural heritage sector because of itshardware simplicity, the acquisition speed as well as its lightweight and smalldimensions. It must be pointed out that since its small number of filters, thissystem has limited analytical capacity and it must be used only for the preliminary mapping and identification of the pigments.

  16. Image Gallery

    Science.gov (United States)

    ... Accredited Practices EER Endowment for Education & Research Journal Image Gallery Click each image to enlarge. Fetal nose/lips Fetal nose, upper ... in the third trimester of pregnancy; the ultrasound image shows the chest of each fetus with the ...

  17. Image Statistics

    Energy Technology Data Exchange (ETDEWEB)

    Wendelberger, Laura Jean [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-08

    In large datasets, it is time consuming or even impossible to pick out interesting images. Our proposed solution is to find statistics to quantify the information in each image and use those to identify and pick out images of interest.

  18. Designing a wearable navigation system for image-guided cancer resection surgery.

    Science.gov (United States)

    Shao, Pengfei; Ding, Houzhu; Wang, Jinkun; Liu, Peng; Ling, Qiang; Chen, Jiayu; Xu, Junbin; Zhang, Shiwu; Xu, Ronald

    2014-11-01

    A wearable surgical navigation system is developed for intraoperative imaging of surgical margin in cancer resection surgery. The system consists of an excitation light source, a monochromatic CCD camera, a host computer, and a wearable headset unit in either of the following two modes: head-mounted display (HMD) and Google glass. In the HMD mode, a CMOS camera is installed on a personal cinema system to capture the surgical scene in real-time and transmit the image to the host computer through a USB port. In the Google glass mode, a wireless connection is established between the glass and the host computer for image acquisition and data transport tasks. A software program is written in Python to call OpenCV functions for image calibration, co-registration, fusion, and display with augmented reality. The imaging performance of the surgical navigation system is characterized in a tumor simulating phantom. Image-guided surgical resection is demonstrated in an ex vivo tissue model. Surgical margins identified by the wearable navigation system are co-incident with those acquired by a standard small animal imaging system, indicating the technical feasibility for intraoperative surgical margin detection. The proposed surgical navigation system combines the sensitivity and specificity of a fluorescence imaging system and the mobility of a wearable goggle. It can be potentially used by a surgeon to identify the residual tumor foci and reduce the risk of recurrent diseases without interfering with the regular resection procedure.

  19. Current studies and future perspectives of synchrotron radiation imaging trials in human patients

    Energy Technology Data Exchange (ETDEWEB)

    Longo, Renata, E-mail: renata.longo@ts.infn.it [Department of Physics, University of Trieste, via Valerio 2 3410 Trieste (Italy); INFN- sezione di Trieste, via Valerio 2 3410 Trieste (Italy)

    2016-02-11

    The coherent and monochromatic x-ray beams available at the synchrotron radiation (SR) laboratories are ideal tools for the development and the initial application of new imaging techniques. In the present paper the history of the clinical studies in k-edge subtraction imaging with SR is summarized, including coronary angiography and bronchography. The results of the recent trial in phase-contrast mammography at Elettra (Trieste, Italy) are discussed, in order to assess the clinical impact of the new imaging modality and the potential interest in its translation to clinical practice. The direct measurement of linear attenuation coefficient obtained during the SR mammography trial is also discussed. The new program of phase-contrast breast CT under development at Elettra is presented. Recently, 3D breast imaging (tomosynthesis and cone beam breast CT) has been introduced in clinical practice with significant improvement in diagnostic accuracy. The aim of this research is to study the contribution of the phase-contrast to the image quality of breast CT. Increasing the image quality of the x-ray medical images at the level of the results obtained at the SR laboratories is highly desirable, hence the promising techniques for the translation of the phase-contrast imaging to the hospitals are briefly discussed.

  20. Designing a wearable navigation system for image-guided cancer resection surgery

    Science.gov (United States)

    Shao, Pengfei; Ding, Houzhu; Wang, Jinkun; Liu, Peng; Ling, Qiang; Chen, Jiayu; Xu, Junbin; Zhang, Shiwu; Xu, Ronald

    2015-01-01

    A wearable surgical navigation system is developed for intraoperative imaging of surgical margin in cancer resection surgery. The system consists of an excitation light source, a monochromatic CCD camera, a host computer, and a wearable headset unit in either of the following two modes: head-mounted display (HMD) and Google glass. In the HMD mode, a CMOS camera is installed on a personal cinema system to capture the surgical scene in real-time and transmit the image to the host computer through a USB port. In the Google glass mode, a wireless connection is established between the glass and the host computer for image acquisition and data transport tasks. A software program is written in Python to call OpenCV functions for image calibration, co-registration, fusion, and display with augmented reality. The imaging performance of the surgical navigation system is characterized in a tumor simulating phantom. Image-guided surgical resection is demonstrated in an ex vivo tissue model. Surgical margins identified by the wearable navigation system are co-incident with those acquired by a standard small animal imaging system, indicating the technical feasibility for intraoperative surgical margin detection. The proposed surgical navigation system combines the sensitivity and specificity of a fluorescence imaging system and the mobility of a wearable goggle. It can be potentially used by a surgeon to identify the residual tumor foci and reduce the risk of recurrent diseases without interfering with the regular resection procedure. PMID:24980159

  1. Multiscale Morphological Filtering for Analysis of Noisy and Complex Images

    Science.gov (United States)

    Kher, A.; Mitra, S.

    1993-01-01

    Images acquired with passive sensing techniques suffer from illumination variations and poor local contrasts that create major difficulties in interpretation and identification tasks. On the other hand, images acquired with active sensing techniques based on monochromatic illumination are degraded with speckle noise. Mathematical morphology offers elegant techniques to handle a wide range of image degradation problems. Unlike linear filters, morphological filters do not blur the edges and hence maintain higher image resolution. Their rich mathematical framework facilitates the design and analysis of these filters as well as their hardware implementation. Morphological filters are easier to implement and are more cost effective and efficient than several conventional linear filters. Morphological filters to remove speckle noise while maintaining high resolution and preserving thin image regions that are particularly vulnerable to speckle noise were developed and applied to SAR imagery. These filters used combination of linear (one-dimensional) structuring elements in different (typically four) orientations. Although this approach preserves more details than the simple morphological filters using two-dimensional structuring elements, the limited orientations of one-dimensional elements approximate the fine details of the region boundaries. A more robust filter designed recently overcomes the limitation of the fixed orientations. This filter uses a combination of concave and convex structuring elements. Morphological operators are also useful in extracting features from visible and infrared imagery. A multiresolution image pyramid obtained with successive filtering and a subsampling process aids in the removal of the illumination variations and enhances local contrasts. A morphology-based interpolation scheme was also introduced to reduce intensity discontinuities created in any morphological filtering task. The generality of morphological filtering techniques in

  2. Extra flat, flexible and disposable endoscope for lateral imaging

    Science.gov (United States)

    Basset, G.; Marinov, D.; Hofer, C.; Cattaneo, S.; Volet, P.; Gallinet, B.; Schnieper, M.; Ferrini, R.

    2016-03-01

    We present an innovative disposable endoscope based on extra flat flexible polymer slabs used as multimode waveguides. The waveguides are compatible with low-cost roll-to-roll production technologies and can be easily customized by patterning, coating and printing techniques according to the specifications of the target application. In order to couple the light (i.e. the illumination beam and the imaging beam) in and out of the waveguide, diffractive subwavelength gratings are used. These nano-scale optical structures enable an efficient and controlled light trapping by total internal reflection, thus minimizing the distortion effects generated by the rough edges. Nano-patterning is obtained using established techniques (i.e. hot embossing and/or UV casting) that are compatible with industrial roll-to-roll production lines or plastic injection molding. Unique features of these innovative endoscopes are i) the achievable very thin form that can be reduced to thicknesses below 200 μm, ii) the ability to record lateral images with respect to the endoscope direction, iii) the ability to image samples (e.g. tissues, tiny objects) in direct contact with the polymer slab, with a minimum imaging distance equal to zero, and iv) the access to high volume fabrication techniques that can enable the production of low-cost disposable endoscopes. A possible device implementation is demonstrated and tested, which consists of a flat line-scanning endoscope enabling the acquisition of 1D images in monochromatic illumination and the reconstruction of 2D images by scanning. Images taken with such a disposable endoscope are discussed and the related technological constraints such as manufacturing tolerances, image distortion, scattered light and signal to noise ratio are further described. Finally, advantages and disadvantages with respect to other endoscopic techniques will be discussed, thus demonstrating the potential of this innovative approach for endoscopic applications in very

  3. Can even monochromatic radiation ensure ideal invisibility?

    Energy Technology Data Exchange (ETDEWEB)

    Rozanov, Nikolai N [St. Petersburg State University of Information Technologies, Mechanics and Optics, St.-Petersburg (Russian Federation)

    2011-07-31

    Discusses conclusions reached by A E Dubinov and D A Mytareva in their paper 'Invisible cloaking of material bodies using the wave flow method' (Usp. Fiz. Nauk 180 475 (2010) [Phys. Usp. 53 455 (2010)]) on whether the perfect optical cloaking of material objects is possible. (letters to the editors)

  4. High efficiency quasi-monochromatic infrared emitter

    Science.gov (United States)

    Brucoli, Giovanni; Bouchon, Patrick; Haïdar, Riad; Besbes, Mondher; Benisty, Henri; Greffet, Jean-Jacques

    2014-02-01

    Incandescent radiation sources are widely used as mid-infrared emitters owing to the lack of alternative for compact and low cost sources. A drawback of miniature hot systems such as membranes is their low efficiency, e.g., for battery powered systems. For targeted narrow-band applications such as gas spectroscopy, the efficiency is even lower. In this paper, we introduce design rules valid for very generic membranes demonstrating that their energy efficiency for use as incandescent infrared sources can be increased by two orders of magnitude.

  5. Cartilage and soft tissue imaging using X-rays: propagation-based phase-contrast computed tomography of the human knee in comparison with clinical imaging techniques and histology.

    Science.gov (United States)

    Horng, Annie; Brun, Emmanuel; Mittone, Alberto; Gasilov, Sergei; Weber, Loriane; Geith, Tobias; Adam-Neumair, Silvia; Auweter, Sigrid D; Bravin, Alberto; Reiser, Maximilian F; Coan, Paola

    2014-09-01

    This study evaluates high-resolution tomographic x-ray phase-contrast imaging in whole human knee joints for the depiction of soft tissue with emphasis on hyaline cartilage. The method is compared with conventional computed tomography (CT), synchrotron radiation absorption-based CT, and magnetic resonance imaging (MRI). After approval of the institutional review board, 2 cadaveric human knees were examined at an synchrotron institution using a monochromatic x-ray beam of 60 keV, a detector with a 90-mm field of view, and a pixel size of 46 × 46 μm. Images of phase-contrast imaging CT were reconstructed with the filtered back projection algorithm and the equally sloped tomography method. Image quality and tissue contrast were evaluated and compared in all modalities and with histology. Phase-contrast imaging provides visualization of altered cartilage regions invisible in absorption CT with simultaneous high detail of the underlying bony abnormalities. The delineation of surface changes is similar to 3-T MRI using cartilage-dedicated sequences. Phase-contrast imaging CT presents soft tissue contrast surpassing that of conventional CT with a clear discrimination of ligamentous, muscular, neural, and vascular structures. In addition, phase-contrast imaging images show cartilage and meniscal calcifications that are not perceptible on conventional CT or on MRI. Phase-contrast imaging CT may facilitate a more complete evaluation of the human knee joint by providing concurrent comprehensive information about cartilage, the underlying subchondral bone, and their changes in osteoarthritic conditions.

  6. Image processing

    NARCIS (Netherlands)

    Heijden, van der F.; Spreeuwers, L.J.; Blanken, H.M.; Vries de, A.P.; Blok, H.E.; Feng, L

    2007-01-01

    The field of image processing addresses handling and analysis of images for many purposes using a large number of techniques and methods. The applications of image processing range from enhancement of the visibility of cer- tain organs in medical images to object recognition for handling by industri

  7. Image city

    DEFF Research Database (Denmark)

    2003-01-01

    Image city exhibition explores a condition of mediation, through a focus on image and sound narratives with a point of departure on a number of Asian cities.......Image city exhibition explores a condition of mediation, through a focus on image and sound narratives with a point of departure on a number of Asian cities....

  8. X-ray imaging and imaging spectroscopy of fusion plasmas and light-source experiments with spherical optics and pixel array detectors

    Science.gov (United States)

    Hill, K. W.; Bitter, M.; Delgado-Aparicio, L.; Pablant, N. A.; Beiersdorfer, P.; Sanchez del Rio, M.; Zhang, L.

    2012-10-01

    High resolution (λ/Δλ ~10,000) 1D imaging x-ray spectroscopy using a spherically bent crystal and a 2D hybrid pixelarray detector (PAD) is used world wide for Doppler measurements of ion-temperature (Ti) and plasma flow-velocityprofiles in magnetic confinement fusion (MCF) plasmas. Meter sized plasmas are diagnosed with cm spatial resolution and 10 ms time resolution. This concept can also be used as a diagnostic of small sources, such as inertial confinement fusion (ICF) plasmas and targets on x-ray light source beam lines, with spatial resolution of microns. A new concept of using matched pairs of spherically bent crystals for monochromatic stigmatic 2D x-ray imaging of mm sized sources offers the possibility of spatial resolution of microns and large solid angle, relative to that achieved with pinhole imaging. Other potential applications of the 2D imaging schemes include x-ray lithography and x-ray microscopy for biological and materials science research. Measurements from MFE plasmas, as well as laboratory experiments and ray tracing computations validating the 1D imaging spectroscopy and 2D x-ray imaging techniques will be presented.

  9. Imaging spectrophotometry of the nuclear outflow of NGC 1068

    Science.gov (United States)

    Cecil, Gerald

    1990-01-01

    This observational program (in conjunction with R. B. Tully (IfA, Honolulu), and J. Bland (Rice U., Houston)) aims to constrain the kinematic organization and dominant excitation mechanisms of ionized gas in active galaxies. More generally, researchers are interested in the dynamics of radiative, supersonic flows in the Interstellar Medium (ISM). Imaging Fabry-Perot interferometers and low-noise Charge Coupled Devices (CCDs) are used for complete spatial coverage of the complex gas distribution in circumnuclear narrow-line regions (NLRs). Extranuclear emission line widths in NLRs can exceed 3000 km s(-1), so to avoid inter-order confusion researchers use an etalon of 4000 km s(-1) free spectral range to map (N II) lambda lambda 6548, 6583 and H alpha. To maximize spatial resolution, researchers select nearby active systems independent of luminosity but known to possess interesting morphologies and/or high-velocity extranuclear ionized gas. Monochromatic images Full Width Half Maximum (FWHM) approx. 65 km s(-1) have thus far been obtained in 1 second or better seeing at the U. Hawaii 2.2m, CFH 3.6m, and CTIO 4.0m telescopes. These are stacked into grids of line profiles, of spectrophotometric quality, at sub-arcsecond increments across a 3 second field. To handle the approx. 20,000 to 300,000 useful spectra that arise from a typical night's work, researchers have developed a complete analysis and reduction package for VAX and Sun image workstations. Reduction involves parametrization of approx. 10 to the 8th raw data points to a few maps (e.g., velocities of each kinematic subsystem, continuum-free line fluxes) containing approx. 10 to the 5th pixels. Researchers identify kinematic and structural symmetries by examining these maps and the point to point variations of the synthesized line profiles. The combination of monochromatic images and full spatial sampling of line profiles has allowed them to isolate such symmetries and has led to reliable kinematic

  10. Analyzer-based imaging of spinal fusion in an animal model

    Science.gov (United States)

    Kelly, M. E.; Beavis, R. C.; Fiorella, David; Schültke, E.; Allen, L. A.; Juurlink, B. H.; Zhong, Z.; Chapman, L. D.

    2008-05-01

    Analyzer-based imaging (ABI) utilizes synchrotron radiation sources to create collimated monochromatic x-rays. In addition to x-ray absorption, this technique uses refraction and scatter rejection to create images. ABI provides dramatically improved contrast over standard imaging techniques. Twenty-one adult male Wistar rats were divided into four experimental groups to undergo the following interventions: (1) non-injured control, (2) decortication alone, (3) decortication with iliac crest bone grafting and (4) decortication with iliac crest bone grafting and interspinous wiring. Surgical procedures were performed at the L5-6 level. Animals were killed at 2, 4 and 6 weeks after the intervention and the spine muscle blocks were excised. Specimens were assessed for the presence of fusion by (1) manual testing, (2) conventional absorption radiography and (3) ABI. ABI showed no evidence of bone fusion in groups 1 and 2 and showed solid or possibly solid fusion in subjects from groups 3 and 4 at 6 weeks. Metal artifacts were not present in any of the ABI images. Conventional absorption radiographs did not provide diagnostic quality imaging of either the graft material or fusion masses in any of the specimens in any of the groups. Synchrotron-based ABI represents a novel imaging technique which can be used to assess spinal fusion in a small animal model. ABI produces superior image quality when compared to conventional radiographs.

  11. Visidep (TM): A Three-Dimensional Imaging System For The Unaided Eye

    Science.gov (United States)

    McLaurin, A. Porter; Jones, Edwin R.; Cathey, LeConte

    1984-05-01

    The VISIDEP process for creating images in three dimensions on flat screens is suitable for photographic, electrographic and computer generated imaging systems. Procedures for generating these images vary from medium to medium due to the specific requirements of each technology. Imaging requirements for photographic and electrographic media are more directly tied to the hardware than are computer based systems. Applications of these technologies are not limited to entertainment, but have implications for training, interactive computer/video systems, medical imaging, and inspection equipment. Through minor modification the system can provide three-dimensional images with accurately measureable relationships for robotics and adds this factor for future developments in artificial intelligence. In almost any area requiring image analysis or critical review, VISIDEP provides the added advantage of three-dimensionality. All of this is readily accomplished without aids to the human eye. The system can be viewed in full color, false-color infra-red, and monochromatic modalities from any angle and is also viewable with a single eye. Thus, the potential of application for this developing system is extensive and covers the broad spectrum of human endeavor from entertainment to scientific study.

  12. Identifying fecal matter contamination in produce fields using multispectral reflectance imaging under ambient solar illumination

    Science.gov (United States)

    Everard, Colm D.; Kim, Moon S.; Lee, Hoonsoo; O'Donnell, Colm P.

    2016-05-01

    An imaging device to detect fecal contamination in fresh produce fields could allow the producer avoid harvesting fecal contaminated produce. E.coli O157:H7 outbreaks have been associated with fecal contaminated leafy greens. In this study, in-field spectral profiles of bovine fecal matter, soil, and spinach leaves are compared. A common aperture imager designed with two identical monochromatic cameras, a beam splitter, and optical filters was used to simultaneously capture two-spectral images of leaves contaminated with both fecal matter and soil. The optical filters where 10 nm full width half maximum bandpass filters, one at 690 nm and the second at 710 nm. These were mounted in front of the object lenses. New images were created using the ratio of these two spectral images on a pixel by pixel basis. Image analysis results showed that the fecal matter contamination could be distinguished from soil and leaf on the ratio images. The use of this technology has potential to allow detection of fecal contamination in produce fields which can be a source of foodbourne illnesses. It has the added benefit of mitigating cross-contamination during harvesting and processing.

  13. Photothermal imaging

    Science.gov (United States)

    Lapotko, Dmitry; Antonishina, Elena

    1995-02-01

    An automated image analysis system with two imaging regimes is described. Photothermal (PT) effect is used for imaging of a temperature field or absorption structure of the sample (the cell) with high sensitivity and spatial resolution. In a cell study PT-technique enables imaging of live non-stained cells, and the monitoring of the cell shape/structure. The system includes a dual laser illumination unit coupled to a conventional optical microscope. A sample chamber provides automated or manual loading of up to 3 samples and cell positioning. For image detection a 256 X 256 10-bit CCD-camera is used. The lasers, scanning stage, and camera are controlled by PC. The system provides optical (transmitted light) image, probe laser optical image, and PT-image acquisition. Operation rate is 1 - 1.5 sec per cell for a cycle: cell positioning -- 3 images acquisition -- image parameters calculation. A special database provides image/parameters storage, presentation, and cell diagnostic according to quantitative image parameters. The described system has been tested during live and stained blood cell studies. PT-images of the cells have been used for cell differentiation. In experiments with the red blood cells (RBC) that originate from normal and anaemia blood parameters for disease differentiation have been found. For white blood cells in PT-images the details of cell structure have found that absent in their optical images.

  14. TIRCIS: thermal infrared compact imaging spectrometer for small satellite applications

    Science.gov (United States)

    Wright, Robert; Lucey, Paul; Crites, Sarah; Garbeil, Harold; Wood, Mark; Pilger, Eric; Gabrieli, Andrea; Honniball, Casey

    2016-10-01

    Measurements of reflectance or emittance in tens of narrow, contiguous wavebands, allow for the derivation of laboratory quality spectra remotely, from which the chemical composition and physical properties of targets can be determined. Although spaceborne (e.g. EO-1 Hyperion) hyperspectral data in the 0.4-2.5 micron (VSWIR) region are available, the provision of equivalent data in the log-wave infrared has lagged behind, there being no currently operational high spatial resolution LWIR imaging spectrometer on orbit. TIRCIS (Thermal Infra-Red Compact Imaging Spectrometer), uses a Fabry-Perot interferometer, an uncooled microbolometer array, and push-broom scanning to acquire hyperspectral image data. Radiometric calibration is provided by blackbody targets while spectral calibration is achieved using monochromatic light sources. The instrument has a mass of <15 kg and dimensions of 53 cm × 25 cm ♢ 22 cm, and has been designed to be compatible with integration into a micro-satellite platform. (A precursor to this instrument was launched onboard a 55 kg microsatellite in October 2015). The optical design yields a 120 m ground sample size given an orbit of 500 km. Over the wavelength interval of 7.5 to 14 microns up to 50 spectral samples are possible. Measured signal-to-noise ratios range from peak values of 500:1 to 1500:1, for source temperature of 10 to 100°C.

  15. Fringing in MonoCam Y4 filter images

    Science.gov (United States)

    Brooks, J.; Fisher-Levine, M.; Nomerotski, A.

    2017-05-01

    We study the fringing patterns observed in MonoCam, a camera with a single Large Synoptic Survey Telescope (LSST) CCD sensor. Images were taken at the U.S. Naval Observatory in Flagstaff, Arizona (NOFS) employing its 1.3 m telescope and an LSST y4 filter. Fringing occurs due to the reflection of infrared light (700 nm or larger) from the bottom surface of the CCD which constructively or destructively interferes with the incident light to produce a net ``fringe'' pattern which is superimposed on all images taken. Emission lines from the atmosphere, dominated by hydroxyl (OH) spectra, can change in their relative intensities as the night goes on, producing different fringe patterns in the images taken. We found through several methods that the general shape of the fringe patterns remained constant, though with slight changes in the amplitude and phase of the fringes. We also found that a superposition of fringes from two monochromatic lines taken in the lab offered a reasonable description of the sky data.

  16. Spectral ladar: towards active 3D multispectral imaging

    Science.gov (United States)

    Powers, Michael A.; Davis, Christopher C.

    2010-04-01

    In this paper we present our Spectral LADAR concept, an augmented implementation of traditional LADAR. This sensor uses a polychromatic source to obtain range-resolved 3D spectral images which are used to identify objects based on combined spatial and spectral features, resolving positions in three dimensions and up to hundreds of meters in distance. We report on a proof-of-concept Spectral LADAR demonstrator that generates spectral point clouds from static scenes. The demonstrator transmits nanosecond supercontinuum pulses generated in a photonic crystal fiber. Currently we use a rapidly tuned receiver with a high-speed InGaAs APD for 25 spectral bands with the future expectation of implementing a linear APD array spectrograph. Each spectral band is independently range resolved with multiple return pulse recognition. This is a critical feature, enabling simultaneous spectral and spatial unmixing of partially obscured objects when not achievable using image fusion of monochromatic LADAR and passive spectral imagers. This enables higher identification confidence in highly cluttered environments such as forested or urban areas (e.g. vehicles behind camouflage or foliage). These environments present challenges for situational awareness and robotic perception which can benefit from the unique attributes of Spectral LADAR. Results from this demonstrator unit are presented for scenes typical of military operations and characterize the operation of the device. The results are discussed here in the context of autonomous vehicle navigation and target recognition.

  17. Ultra-realistic imaging: a new beginning for display holography

    Science.gov (United States)

    Bjelkhagen, Hans I.; Brotherton-Ratcliffe, David

    2014-02-01

    Recent improvements in key foundation technologies are set to potentially transform the field of Display Holography. In particular new recording systems, based on recent DPSS and semiconductor lasers combined with novel recording materials and processing, have now demonstrated full-color analogue holograms of both lower noise and higher spectral accuracy. Progress in illumination technology is leading to a further major reduction in display noise and to a significant increase of the clear image depth and brightness of such holograms. So too, recent progress in 1-step Direct-Write Digital Holography (DWDH) now opens the way to the creation of High Virtual Volume Displays (HVV) - large format full-parallax DWDH reflection holograms having fundamentally larger clear image depths. In a certain fashion HVV displays can be thought of as providing a high quality full-color digital equivalent to the large-format laser-illuminated transmission holograms of the sixties and seventies. Back then, the advent of such holograms led to much optimism for display holography in the market. However, problems with laser illumination, their monochromatic analogue nature and image noise are well cited as being responsible for their failure in reality. Is there reason for believing that the latest technology improvements will make the mark this time around? This paper argues that indeed there is.

  18. Monitoring combat wound healing by IR hyperspectral imaging

    Science.gov (United States)

    Howle, Chris R.; Spear, Abigail M.; Gazi, Ehsan; Crane, Nicole J.

    2016-03-01

    In recent conflicts, battlefield injuries consist largely of extensive soft injuries from blasts and high energy projectiles, including gunshot wounds. Repair of these large, traumatic wounds requires aggressive surgical treatment, including multiple surgical debridements to remove devitalised tissue and to reduce bacterial load. Identifying those patients with wound complications, such as infection and impaired healing, could greatly assist health care teams in providing the most appropriate and personalised care for combat casualties. Candidate technologies to enable this benefit include the fusion of imaging and optical spectroscopy to enable rapid identification of key markers. Hence, a novel system based on IR negative contrast imaging (NCI) is presented that employs an optical parametric oscillator (OPO) source comprising a periodically-poled LiNbO3 (PPLN) crystal. The crystal operates in the shortwave and midwave IR spectral regions (ca. 1.5 - 1.9 μm and 2.4 - 3.8 μm, respectively). Wavelength tuning is achieved by translating the crystal within the pump beam. System size and complexity are minimised by the use of single element detectors and the intracavity OPO design. Images are composed by raster scanning the monochromatic beam over the scene of interest; the reflection and/or absorption of the incident radiation by target materials and their surrounding environment provide a method for spatial location. Initial results using the NCI system to characterise wound biopsies are presented here.

  19. A regularized tri-linear approach for optical interferometric imaging

    CERN Document Server

    Birdi, Jasleen; Wiaux, Yves

    2016-01-01

    In the context of optical interferometry, only under-sampled power spectrum and bispectrum data are accessible. It poses an ill-posed inverse problem for image recovery. Recently, a tri-linear model was proposed for monochromatic imaging, leading to an alternated minimization problem. In that work, only a positivity constraint was considered, and the problem was solved by an approximated Gauss-Seidel method. In this paper, we propose to improve the approach on three fundamental aspects. Firstly, we define the estimated image as a solution of a regularized minimization problem, promoting sparsity in a fixed dictionary using either an $\\ell_1$ or a weighted-$\\ell_1$ regularization term. Secondly, we solve the resultant non-convex minimization problem using a block-coordinate forward-backward algorithm. This algorithm is able to deal both with smooth and non-smooth functions, and benefits from convergence guarantees even in a non-convex context. Finally, we generalize our model and algorithm to the hyperspectral...

  20. The CORONAS-Photon/TESIS experiment on EUV imaging spectroscopy of the Sun

    Science.gov (United States)

    Kuzin, S.; Zhitnik, I.; Bogachev, S.; Bugaenko, O.; Ignat'ev, A.; Mitrofanov, A.; Perzov, A.; Shestov, S.; Slemzin, V.; Suhodrev, N.

    The new experiment TESIS is developent for russian CORONAS-Photon mission launch is planned on the end of 2007 The experiment is aimed on the study of activity of the Sun in the phases of minimum rise and maximum of 24 th cycle of Solar activity by the method of XUV imaging spectroscopy The method is based on the registration full-Sun monochromatic images with high spatial and temporal resolution The scientific tasks of the experiment are i Investigation dynamic processes in corona flares CME etc with high spatial up to 1 and temporal up to 1 second resolution ii determination of the main plasma parameters like plasma electron and ion density and temperature differential emission measure etc iii study of the processes of appearance and development large scale long-life magnetic structures in the solar corona study of the fluency of this structures on the global activity of the corona iv study of the mechanisms of energy accumulation and release in the solar flares and mechanisms of transformation of this energy into the heating of the plasma and kinematics energy To get the information for this studies the TESIS will register full-Sun images in narrow spectral intervals and the monochromatic lines of HeII SiXI FeXXI-FeXXIII MgXII ions The instrument includes 5 independent channels 2 telescopes for 304 and 132 A wide-field 2 5 degrees coronograph 280-330A and 8 42 A spectroheliographs The detailed description of the TESIS experiment and the instrument is presented