WorldWideScience

Sample records for rutherford backscattering analysis

  1. Rutherford backscattering analysis of contaminants in PET

    Science.gov (United States)

    Pierce, D. E.; Pfeffer, R. L.; Sadler, G. D.

    1997-05-01

    Rutherford Backscattering Spectrometry (RBS) was used to understand the sorption and desorption of organic contaminants in the polymer Poly(ethylene terephthalate), or PET. Samples were exposed to a range of organics to simulate contamination of PET that can take place in the post-consumer waste stream. From RBS analysis, concentration depth profiles were shown to vary from a monolayer regime surface layer to a saturation level, depending on the contaminant. Heat treatments were also applied to contaminated polymer to simulate thermal processing steps in the recycling of PET. Heating caused a dramatic decrease in contaminants and in some cases a complete removal of contamination was achieved to the limit of RBS detectability.

  2. Artificial neural networks for instantaneous analysis of real-time Rutherford backscattering spectra

    Energy Technology Data Exchange (ETDEWEB)

    Demeulemeester, J., E-mail: Jelle.Demeulemeester@fys.kuleuven.b [Instituut voor Kern- en Stralingsfysica and INPAC, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Smeets, D. [Instituut voor Kern- en Stralingsfysica and INPAC, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Barradas, N.P. [Instituto Tecnologico e Nuclear, Estrada Nacional 10, Apartado 21, 2686-953 Sacavem (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1699 Lisboa Codex (Portugal); Vieira, A. [Instituto Superior de Engenharia do Porto, Rua S. Tome, 4200 Porto (Portugal); Comrie, C.M. [Department of Physics, University of Cape Town, Rondebosch 7700 (South Africa); Temst, K.; Vantomme, A. [Instituut voor Kern- en Stralingsfysica and INPAC, K.U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)

    2010-05-15

    This paper reports on the advantage of using artificial neural networks (ANNs) to analyze large sets of real-time Rutherford backscattering spectrometry (RBS) data. Real-time RBS, i.e. collecting RBS spectra at periodic time intervals during a thermal treatment, probes the full response of a thin film to the annealing in situ. Although very valuable insights can be gained by this technique, the time-consuming analysis of the vast amount of RBS spectra acquired during real-time RBS measurements has so far prevented the widespread use of real-time RBS. Setting up an ANN is quite an intensive process as well, but once trained, these ANNs can handle the analysis of large data sets practically instantaneously. As such, the beneficial combination of real-time RBS and ANN analysis forms a perfect synergy. In this test case, a network was trained and applied to analyze the Ni silicide growth during annealing of a thin 80 nm Ni film on Si(1 0 0). The ANN performance was validated by comparing the ANN results with the conventional analysis performed on the same data set.

  3. Rutherford Backscattering Spectrometry analysis of iron-containing Bi2Se3 topological insulator thin films

    Science.gov (United States)

    Alarcon-Diez, V.; Eddrief, M.; Vickridge, I.

    2016-03-01

    Fe-containing Bi2Se3 topological insulators (TI) thin films have been grown to investigate the intricate interplay between topological order and the incorporation of ferromagnetic atoms. Here we present the quantitative characterisation of the Bi2Se3 thin films with up to 16 at% Fe incorporated during the growth process on GaAs (1 1 1) substrate by Molecular Beam Epitaxy. We report the elemental composition and depth profiles of the Bi2Se3:Fe films obtained using Rutherford Backscattering Spectrometry (RBS) and their formed crystalline phase obtained by X-ray diffraction (XRD). Resistance of the TI to beam-induced damage was investigated by channelling RBS. Using the elemental composition from RBS and the thickness from XRD measurements the Fe-free film density was deduced. For Fe-containing samples, the diffraction reveals the formation of two distinct crystalline phases, as well as their intergrowth pattern, in which the basal planes of Bi2Se3 coexist with an additional Fe-Se phase. This intergrown composite, with chemical compatibility of the Fe-Se phase with the crystalline Bi2Se3 structure, preserves the intrinsic topological surface states of the TI component despite the inhomogeneous distribution of the constituent phases. RBS analysis gives the stoichiometry of the Bi2Se3, and Bi2Se3:Fe samples (estimated between 0 and 16 at% Fe) and gives insights into the composition of FeSex phases present.

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

    Directory of Open Access Journals (Sweden)

    Pia C. Lansåker

    2014-10-01

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

  5. Lattice location of O18 in ion implanted Fe crystals by Rutherford backscattering spectrometry, channeling and nuclear reaction analysis

    Science.gov (United States)

    Vairavel, Mathayan; Sundaravel, Balakrishnan; Panigrahi, Binaykumar

    2016-09-01

    There are contradictory theoretical predictions of lattice location of oxygen interstitial atom at tetrahedral and octahedral interstices in bcc Fe. For validating these predictions, 300 keV O18 ions with fluence of 5 × 1015 ions/cm2 are implanted into bcc Fe single crystals at room temperature and annealed at 400 °C. The Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA)/channeling measurements are carried out with 850 keV protons. The lattice location of implanted O18 is analysed using the α-particles yield from O18(p,α)N15 nuclear reaction. The tilt angular scans of α-particle yield along and axial directions are performed at room temperature. Lattice location of O18 is found to be at tetrahedral interstitial site by comparing the experimental scan with simulated scans using FLUX7 software.

  6. Simulation of Rutherford backscattering spectrometry from arbitrary atom structures

    Science.gov (United States)

    Zhang, S.; Nordlund, K.; Djurabekova, F.; Zhang, Y.; Velisa, G.; Wang, T. S.

    2016-10-01

    Rutherford backscattering spectrometry in a channeling direction (RBS/C) is a powerful tool for analysis of the fraction of atoms displaced from their lattice positions. However, it is in many cases not straightforward to analyze what is the actual defect structure underlying the RBS/C signal. To reveal insights of RBS/C signals from arbitrarily complex defective atomic structures, we develop here a method for simulating the RBS/C spectrum from a set of arbitrary read-in atom coordinates (obtained, e.g., from molecular dynamics simulations). We apply the developed method to simulate the RBS/C signals from Ni crystal structures containing randomly displaced atoms, Frenkel point defects, and extended defects, respectively. The RBS/C simulations show that, even for the same number of atoms in defects, the RBS/C signal is much stronger for the extended defects. Comparison with experimental results shows that the disorder profile obtained from RBS/C signals in ion-irradiated Ni is due to a small fraction of extended defects rather than a large number of individual random atoms.

  7. Investigation of the solid-state reaction between nickel oxide and alumina by Rutherford backscattering (RBS)

    NARCIS (Netherlands)

    Roos, G. de; Geus, John W.; Fluit, J.M.; Wit, J.H. de

    1980-01-01

    The reaction of NiO and Al2O3 to form NiAl2O4 was investigated by means of Rutherford backscattering of 3 MeV He+-ions. The NiO was obtained by oxidation at 900°C of a nickel film vapour-deposited onto alumina substrates. The reaction of NiO and Al2O3 did not proceed markedly at 900°C. The reaction

  8. Interface defects in GaN/sapphire studied using Rutherford backscattering spectroscopy and channeling

    Indian Academy of Sciences (India)

    S K Sinha; P K Barhai

    2004-06-01

    GaN on sapphire was grown by MOCVD technique. Rutherford backscattering spectra together with channeling along [0 0 0 1] axis were recorded to study the defects at the interface. Detailed calculation shows that the defects at GaN/sapphire interface are due to dislocations which are distributed into the whole thickness of the film and are mainly aligned on the growth direction.

  9. Study of cerium diffusion in undoped lithium-6 enriched glass with Rutherford backscattering spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaodong, E-mail: xzhang39@utk.edu [Department of Nuclear Engineering, University of Tennessee, TN 37996 (United States); Moore, Michael E.; Lee, Kyung-Min; Lukosi, Eric D. [Department of Nuclear Engineering, University of Tennessee, TN 37996 (United States); Hayward, Jason P. [Department of Nuclear Engineering, University of Tennessee, TN 37996 (United States); Oak Ridge National Lab, Oak Ridge, TN 37831 (United States)

    2016-07-01

    Undoped lithium-6 enriched glasses coated with pure cerium (99.9%) with a gold protection layer on top were heated at three different temperatures (500, 550, and 600 °C) for varied durations (1, 2, and 4 h). Diffusion profiles of cerium in such glasses were obtained with the conventional Rutherford backscattering technique. Through fitting the diffusion profiles with the thin-film solution of Fick’s second law, diffusion coefficients of cerium with different annealing temperatures and durations were solved. Then, the activation energy of cerium for the diffusion process in the studied glasses was found to be 114 kJ/mol with the Arrhenius equation.

  10. Study of cerium diffusion in undoped lithium-6 enriched glass with Rutherford backscattering spectrometry

    Science.gov (United States)

    Zhang, Xiaodong; Moore, Michael E.; Lee, Kyung-Min; Lukosi, Eric D.; Hayward, Jason P.

    2016-07-01

    Undoped lithium-6 enriched glasses coated with pure cerium (99.9%) with a gold protection layer on top were heated at three different temperatures (500, 550, and 600 °C) for varied durations (1, 2, and 4 h). Diffusion profiles of cerium in such glasses were obtained with the conventional Rutherford backscattering technique. Through fitting the diffusion profiles with the thin-film solution of Fick's second law, diffusion coefficients of cerium with different annealing temperatures and durations were solved. Then, the activation energy of cerium for the diffusion process in the studied glasses was found to be 114 kJ/mol with the Arrhenius equation.

  11. Proton irradiation induced defects in GaN: Rutherford backscattering and thermally stimulated current studies

    Science.gov (United States)

    Nakamura, T.; Nishikata, N.; Kamioka, K.; Kuriyama, K.; Kushida, K.

    2016-03-01

    The proton irradiation induced defects in GaN are studied by combining elastic recoil detection analysis (ERDA), thermally stimulated current (TSC), and Rutherford backscattering spectroscopy (RBS) measurements. The proton irradiation (peak concentration: 1.0 × 1015 cm-2) into GaN films with a thickness of 3 μm is performed using a 500 keV implanter. The proton concentration by a TRIM simulation is maximum at 3600 nm in depth, which means that the proton beam almost passes through the GaN film. The carrier concentration decreases three orders of magnitude to 1015 cm-3 by the proton irradiation, suggesting the existence of the proton irradiation-induced defects. The ERDA measurements using the 1.5 MeV helium beam can evaluate hydrogen from the surface to ∼300 nm. The hydrogen concentration at ∼220 nm is ∼8.3 × 1013 cm-2 and ∼1.0 × 1014 cm-2 for un-irradiated and as-irradiated samples, respectively, suggesting that electrical properties are almost not affected by hydrogen. TSC measurements show a broad spectrum at around 110 K which can be divided into three traps, P1 (ionization energy 173 meV), P2 (251 meV), and P3 (330 meV). The peak intensity of P1 is much larger than that of P2 and P3. These traps are related to the N vacancy and/or complex involving N vacancy (P1), neutral Ga vacancy (VGa) (P2), and complex involving VGa (P3). The Ga displacement concentration evaluated by RBS measurements is 1.75 × 1019 cm-3 corresponding to 1/1000 of the Ga concentration in GaN. The observed Ga displacement may be origins of P2 and P3 traps.

  12. Rutherford backscattering and channelling studies of erbium implanted SIMOX refid="FN1">**SIMOX: separation by implanted oxygen. structures

    Science.gov (United States)

    Zhang, Jingping; Tang, Y. S.; Hemment, P. L. F.; Sealy, B. J.

    1990-04-01

    The behaviour of 250 keV 166Er + implanted into SIMOX structures has been investigated by Rutherford backscattering and channelling analysis. The implantation doses were 1.5 ×10 14 cm -2 and 1.5 × 10 15 cm -2. Both conventional furnace and rapid therm annealing were carried out in the temperature range 600°C-1100°C. Regrowth of the amorphized silicon and redistribution of the erbium were found to be strongly influenced by the status of the damaged layer. Different regrowth processes of the completely damaged silicon overlayer were suggested respectively for conventional furnace and rapid thermal annealing. It is found that the regrowth rate increases rapidly when the temperature is higher than 900° C in both cases. The redistribution of the erbium atoms was controlled by the regrowth boundary between the damaged and the recrystallized silicon.

  13. Rutherford Backscattering Spectrometry studies of 100 keV nitrogen ion implanted polypropylene polymer

    Science.gov (United States)

    Chawla, Mahak; Aggarwal, Sanjeev; Sharma, Annu

    2017-09-01

    The effect of nitrogen ion implantation on the structure and composition in polypropylene (PP) polymer has been studied. Implantation was carried out using 100 keV N+ ions at different fluences of 1 × 1015, 1 × 1016 and 1 × 1017 ions cm-2 with beam current density of ∼0.65 μA cm-2. Surface morphological changes in the pre- and post-implanted PP specimens have been studied using Rutherford Backscattering Spectrometry (RBS) and UV-Visible Spectroscopy. The spatial distribution of implantation induced modification in the form of carbonization and dehydrogenation in the near surface region of PP matrix, the projected range, retained dose of implanted nitrogen, the various elements present in the implanted layers and their differential cross-sections have been analyzed using RBS spectra. RUMP simulation yielded an increase in the concentration of carbon near the surface from 33 at.% (virgin) to 42 at.% at fluence of 1 × 1017 N+ cm-2. Further, optical absorption has been found to increase with a shift in the absorption edge from UV towards visible region with increasing fluence. UV-Vis absorption spectra also indicate a drastic decrease in optical energy gap from 4.12 eV (virgin) to 0.25 eV (1 × 1017 N+ cm-2) indicating towards the formation of carbonaceous network in the implanted region. All these changes observed using UV-Visible have been further correlated with the outcomes of the RBS characterization.

  14. Computer simulation program for medium-energy ion scattering and Rutherford backscattering spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Tomoaki, E-mail: t-nishi@hosei.ac.jp

    2016-03-15

    A computer simulation program for ion scattering and its graphical user interface (MEISwin) has been developed. Using this program, researchers have analyzed medium-energy ion scattering and Rutherford backscattering spectrometry at Ritsumeikan University since 1998, and at Rutgers University since 2007. The main features of the program are as follows: (1) stopping power can be chosen from five datasets spanning several decades (from 1977 to 2011), (2) straggling can be chosen from two datasets, (3) spectral shape can be selected as Gaussian or exponentially modified Gaussian, (4) scattering cross sections can be selected as Coulomb or screened, (5) simulations adopt the resonant elastic scattering cross section of {sup 16}O({sup 4}He, {sup 4}He){sup 16}O, (6) pileup simulation for RBS spectra is supported, (7) natural and specific isotope abundances are supported, and (8) the charge fraction can be chosen from three patterns (fixed, energy-dependent, and ion fraction with charge-exchange parameters for medium-energy ion scattering). This study demonstrates and discusses the simulations and their results.

  15. Computer simulation program for medium-energy ion scattering and Rutherford backscattering spectrometry

    Science.gov (United States)

    Nishimura, Tomoaki

    2016-03-01

    A computer simulation program for ion scattering and its graphical user interface (MEISwin) has been developed. Using this program, researchers have analyzed medium-energy ion scattering and Rutherford backscattering spectrometry at Ritsumeikan University since 1998, and at Rutgers University since 2007. The main features of the program are as follows: (1) stopping power can be chosen from five datasets spanning several decades (from 1977 to 2011), (2) straggling can be chosen from two datasets, (3) spectral shape can be selected as Gaussian or exponentially modified Gaussian, (4) scattering cross sections can be selected as Coulomb or screened, (5) simulations adopt the resonant elastic scattering cross section of 16O(4He, 4He)16O, (6) pileup simulation for RBS spectra is supported, (7) natural and specific isotope abundances are supported, and (8) the charge fraction can be chosen from three patterns (fixed, energy-dependent, and ion fraction with charge-exchange parameters for medium-energy ion scattering). This study demonstrates and discusses the simulations and their results.

  16. Kinetic study of wet oxidation of Si0.5Ge0.5 alloy by Rutherford backscattering spectroscopy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The oxidation of Si0. sGeo.5 alloy has been investigated at the temperatures of 800℃ and 900 ℃. Rutherford backscattering spectroscopy has been employed to determine the composition and thickness of the oxide layers. Only Sio.5Geo. 5O2 layer formed during the oxidation at 800℃, whilst three layers, Si0.5Ge0.5O2, SiO2 and Ge, are existed after the oxidation at 900℃. Experimental results are interpreted by adding a germanium flux F4 in Deal-Grove oxidation model of Silicon.

  17. Stoichiometry and local bond configuration of In2S3:Cl thin films by Rutherford backscattering spectrometry

    Science.gov (United States)

    Juma, Albert O.

    2016-10-01

    In2S3 thin films deposited using chemical methods always contain residual elements from the precursors, which modify their properties. As buffer layers in solar cells, the residual elements in the In2S3 layer affect the performance of these devices. The stoichiometry of In2S3 thin films deposited by spray ion layer gas reaction (ILGAR) was studied as a function of the residual Cl from InCl3 precursor by varying the deposition parameters. The chemical formula was deduced from the elemental composition determined using Rutherford backscattering (RBS). Incomplete sulfurization of the precursor implies that residual Cl- remains bonded to the In3+ ions while some occupy interstitial and/or antisite positions in the In2S3 matrix. This results in thin films with different stoichiometry, described by the formula In4S6-xCl2x+2y. This changes the local bond configuration and geometry and underpins the influence of residual Cl on the physical properties of In2S3 thin films.

  18. Interaction of europium and nickel with calcite studied by Rutherford Backscattering Spectrometry and Time-Resolved Laser Fluorescence Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Sabau, A. [Agence Nationale pour la gestion des Déchets RAdioactifs, 1-7 rue J. Monnet, Parc de la Croix Blanche, 92298 Châtenay-Malabry Cedex (France); Université de Nice Sophia Antipolis, Ecosystèmes Côtiers Marins et Réponses aux Stress (ECOMERS), 28 avenue Valrose, 06108 Nice Cedex 2 (France); Pipon, Y., E-mail: pipon@ipnl.in2p3.fr [Institut de Physique Nucléaire de Lyon (IPNL), Université Lyon 1, CNRS/IN2P3, 4 rue Enrico Fermi, 69 622 Villeurbanne Cedex (France); Institut Universitaire de Technologie (IUT) Lyon-1, Université Claude Bernard Lyon 1, 69 622 Villeurbanne Cedex (France); Toulhoat, N. [Institut de Physique Nucléaire de Lyon (IPNL), Université Lyon 1, CNRS/IN2P3, 4 rue Enrico Fermi, 69 622 Villeurbanne Cedex (France); CEA/DEN, Saclay, 91191 Gif sur Yvette (France); Lomenech, C. [Université de Nice Sophia Antipolis, Ecosystèmes Côtiers Marins et Réponses aux Stress (ECOMERS), 28 avenue Valrose, 06108 Nice Cedex 2 (France); Jordan, N. [Helmholtz Zentrum Dresden Rossendorf (HZDR), Institute of Resource Ecology (IRE) (Germany); Moncoffre, N. [Institut de Physique Nucléaire de Lyon (IPNL), Université Lyon 1, CNRS/IN2P3, 4 rue Enrico Fermi, 69 622 Villeurbanne Cedex (France); Barkleit, A. [Helmholtz Zentrum Dresden Rossendorf (HZDR), Institute of Resource Ecology (IRE) (Germany); and others

    2014-08-01

    This study aims at elucidating the mechanisms regulating the interaction of Eu and Ni with calcite (CaCO{sub 3}). Calcite powders or single crystals (some mm sized) were put into contact with Eu or Ni solutions at concentrations ranging from 10{sup −3} to 10{sup −5} mol L{sup −1} for Eu and 10{sup −3} mol L{sup −1} for Ni. The sorption durations ranged from 1 week to 1 month. Rutherford Backscattering Spectrometry (RBS) well adapted to discriminate incorporation processes such as: (i) adsorption or co precipitation at the mineral surfaces or, (ii) incorporation into the mineral structure (through diffusion for instance), has been carried out. Moreover, using the fluorescence properties of europium, the results have been compared to those obtained by Time-Resolved Laser Fluorescence Spectroscopy (TRLFS) on calcite powders. For the single crystals, complementary SEM observations of the mineral surfaces at low voltage were also performed. Results showed that Ni accumulates at the calcite surface whereas Eu is also incorporated at a greater depth. Eu seems therefore to be incorporated into two different states in calcite: (i) heterogeneous surface accumulation and (ii) incorporation at depth greater than 160 nm after 1 month of sorption. Ni was found to accumulate at the surface of calcite without incorporation.

  19. FEM Analysis of Nb-Sn Rutherford-type Cables

    Energy Technology Data Exchange (ETDEWEB)

    Barzi, Emanuela; Gallo, Giuseppe; Neri, Paolo; /Fermilab

    2011-01-01

    An important part of superconducting accelerator magnet work is the conductor. To produce magnetic fields larger than 10 T, brittle conductors are typically used. For instance, for Nb{sub 3}Sn the original round wire, in the form of a composite of Copper, Niobium and Tin, is assembled into a so-called Rutherford-type cable, which is used to wind the magnet. The magnet is then subjected to a high temperature heat treatment to produce the chemical reactions that make the material superconducting. At this stage the superconductor is brittle and its superconducting properties sensitive to strain. This work is based on the development of a 2D finite element model, which simulates the mechanical behavior of Rutherford-type cable before heat treatment. The model was applied to a number of different cable architectures. To validate a critical criterion adopted into the single Nb-Sn wire analysis, the results of the model were compared with those measured experimentally on cable cross sections.

  20. A remotely controlled, semi-automatic target system for Rutherford backscattering spectrometry and elastic recoil detection analyses of polymeric membrane samples

    Energy Technology Data Exchange (ETDEWEB)

    Attayek, P.J. [Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7431 (United States); Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7575 (United States); Meyer, E.S.; Lin, L. [Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7431 (United States); Rich, G.C.; Clegg, T.B. [Triangle Universities Nuclear Laboratory (TUNL), Durham, NC 27708-0308 (United States); Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255 (United States); Coronell, O., E-mail: coronell@unc.edu [Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7431 (United States)

    2012-06-01

    A new target system for Rutherford backscattering spectrometry and elastic recoil detection analysis is described which enables remotely controlled, semi-automatic analysis of multiple organic polymer samples without exceeding damaging incident beam fluences. Control of fluence at a given beam current is achieved using two stepper motors to move a thin aluminum disk loaded with polymer samples both radially and azimuthally across the beam. Flexible beam spot locations and sample irradiation times are remotely controlled in two steps via two custom LabVIEW Trade-Mark-Sign programs. In the first step, a digital image of the target disk is converted into precise radial and azimuthal coordinates for each mounted polymer sample. In the second step, the motors implement the user-directed sample irradiation and fluence. Schematics of the target system hardware, a block diagram of interactions between the target system components, a description of routine procedures, and illustrative data taken with a 2 MeV {sup 4}He{sup 2+} analysis beam are provided.

  1. Selective Rutherford backscattering techniques in the study of transition-metal implanted YBa{sub 2}C{sub 3}O{sub 7-{delta}}

    Energy Technology Data Exchange (ETDEWEB)

    Martin, J.W.; Russell, G.J. [New South Wales Univ., Kensington, NSW (Australia). School of Physics; Cohen, D.D.; Evans, P.J. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1993-12-31

    Using a metal-vapor vacuum arc ion source, several as-grown, large single crystal YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} were implanted with a dose of 1x10{sup 17} zinc, nickel and iron ions. After implantation the crystal was subjected to two anneal cycles that has allowed to examine crystal structure, superconducting transitions and composition, through X-ray diffraction, rutherford backscattering spectroscopy (RBS) and AC susceptibility measurements respectively. Although RBS discriminates strongly against light elements, such as oxygen, the use of resonant reaction {sup 16}O ({alpha}, {alpha}){sup 16}O at 3.4 MeV was beneficial, as its cross section is nearly 23 times that of the rutherford cross section. 4 figs.

  2. Characterization of a compact filament-driven multicusp ion source for low energy time-of-flight Rutherford backscattering spectrometry application

    Science.gov (United States)

    Dangtip, S.; Junphong, P.; Ano, V.; Lekprasert, B.; Suwannakachorn, D.; Thongnopparat, N.; Vilaithong, T.

    2004-05-01

    Because of the limited pulse height energy resolution of a detector, conventional Rutherford backscattering spectrometry (RBS) requires an energy of the incident α particle to be in the MeV region. At Chiang Mai University we have researched the possibility of utilizing a 280 keV nanosecond pulse of helium ions for RBS applications. We have chosen a compact filament-driven multicusp ion source of 2.6 cm in diameter and 8 cm in length being investigated for the time-of-flight RBS applications. In this article, we present the general ion source performance using helium, nitrogen, and argon for generating the discharge plasma. The general ion source characteristics have been measured and analyzed. The measurements also include the extractable ion current and the ion beam emittance. We have performed beam extraction calculations with a computer simulation code KOBRA. Results of the measurements and calculations will be presented and discussed.

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  4. Characterization of a ZnO Epilayer Grown on Sapphire by using Rutherford Backscattering/Channeling and X-Ray Diffraction

    Institute of Scientific and Technical Information of China (English)

    DING Bin-Feng

    2012-01-01

    A ZnO layer with rather good crystalline quality (Xmin =9.4%) is grown on a sapphire substrate by plasma enhanced chemical vapor deposition (PECVD).Rutherford backscattering (RBS)/channeling and high-resolution x-ray diffraction (XRD) are used to characterize the elastic strain in the ZnO epilayer.The tetragonal distortion is positive and depth dependent.It is highest near the interface and decreases towards the sample surface.By combining the results of RBS and XRD,the average elastic strains in the parallel and the perpendicular directions can be calculated to be 0.50% and -0.17%,respectively.

  5. Sputtering of SiN films by 540 keV C{sub 60}{sup 2+} ions observed using high-resolution Rutherford backscattering spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, K.; Morita, Y.; Kitayama, T.; Suzuki, M. [Department of Micro Engineering, Kyoto University, Kyoto 615-8540 (Japan); Narumi, K.; Saitoh, Y. [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gumma 370-1292 (Japan); Tsujimoto, M.; Isoda, S. [Institute for Integrated Cell-Material Sciences, Kyoto University, Kyoto 606-8501 (Japan); Fujii, Y. [Center for Supports to Research and Education Activities, Kobe University, Kobe 657-8501 (Japan); Kimura, K., E-mail: kimura@kues.kyoto-u.ac.jp [Department of Micro Engineering, Kyoto University, Kyoto 615-8540 (Japan)

    2014-08-01

    Amorphous silicon nitride films deposited on Si(0 0 1) were irradiated with 540 keV C{sub 60} ions to fluences ranging from 2.5 × 10{sup 11} to 1 × 10{sup 14} ions/cm{sup 2}. The composition depth profiles of the irradiated samples were measured using high-resolution Rutherford backscattering spectroscopy. Both silicon and nitrogen in the film decrease rapidly with fluence. From the observed result the sputtering yields are obtained as 3900 ± 500 N atoms/ion and 1500 ± 1000 Si atoms/ion. Such large sputtering yield cannot be explained by either the elastic sputtering or the electronic sputtering, indicating that the synergy effect between the elastic sputtering and the electronic sputtering plays an important role.

  6. Computerized Control and Operation of Rutherford Backscattering/Channeling for an in situ Ion Beam System and Its Application for Measurement of Si(001) and ZnO(001)

    Institute of Scientific and Technical Information of China (English)

    HE Jun; J. C. LEE; LI Ming; WANG Ze-Song; LIU Chuan-Sheng; FU De-Jun

    2011-01-01

    A computer-automated Rutherford backscattering/channeling (RBS/C) system is developed to provide in situ ion beam analysis of the accelerator-TEM system in Wuhan University. The basic system components are a PC equipped with a multichannel analyzer data acquisition board, motion control hardware including the Panmure stepping motor controller and integrated circuit modules, and a Labview programmed operating system with associated electronics. Single crystalline Si(Ool) and ZnO(Ool) implanted with Mn ions were characterized with this computerized setup. The crystalline quality Xmin and channeling half angle of Si(001) were measured to be 4.65% and 0.52°, respectively, which are comparable to theoretical values 4.2% and 0.32°. The ion implantation induced damage depth profile derived from channeling and random spectrum is in reasonable agreement with the result calculated by the SRIM Monte-Carlo simulation code.

  7. Dislocation and Elastic Strain in an InN Film Characterized by Synchrotron Radiation X-Ray Diffraction and Rutherford Backscattering/Channeling

    Institute of Scientific and Technical Information of China (English)

    CHENG Feng-Feng; FA Tao; WANG Xin-Qiang; YAO Shu-De

    2012-01-01

    Dislocation information and strain-related tetragonal distortion as well as crystalline qualities of a 2-μm-thick InN film grown by molecular beam epitaxy (MBE) are characterized by Rutherford backscattering/channeling (RBS/C) and synchrotron radiation x-ray diffraction (SR-XRD).The minimum yield xmin=2.5% deduced from the RBS/C results indicates a fairly good crystalline quality.From the SR-XRD results,we obtain the values of the screw and edge densities to be ρscrew =7.0027 X 109 and ρedge =8.6115 × 109 cm-2,respectively.The tetragonal distortion of the sample is found to be -0.27 % by angular scans,which is close to the -0.28 % derived by SR-XRD.The value of |e(⊥)/e‖| =0.6742 implies that the InN layer is much stiffer along the a axis than that along the c axis,where e‖ is the parallel elastic strain,and e⊥ is the perpendicular elastic strain.Photoluminescence results reveal a main peak of 0.653eV with the linewidth of 60meV,additional shoulder band could be due to impurities and related defects.%Dislocation information and strain-related tetragonal distortion as well as crystalline qualities of a 2-μm-thick InN film grown by molecular beam epitaxy (MBE) are characterized by Rutherford backscattering/'channeling (RBS/C) and synchrotron radiation x-ray diffraction (SR-XRD). The minimum yield Xmin=2.5% deduced from the RBS/C results indicates a fairly good crystalline quality. From the SR-XRD results, we obtain the values of the screw and edge densities to be pscrew = 7.0027 ×109 and pedge = 8.6115 ×109 cm-2, respectively. The tetragonal distortion of the sample is found to be-0.27% by angular scans, which is close to the -0.28 % derived by SR-XRD. The value of |e⊥/e|| | = 0.6742 implies that the InN layer is much stiffer along the a axis than that along the c axis, where e|| is the parallel elastic strain, and e⊥ is the perpendicular elastic strain. Photoluminescence results reveal a main peak of 0.653eV with the linewidth of 60me

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-04-01

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

  9. Rutherford's war

    Science.gov (United States)

    Campbell, John

    2016-02-01

    Seagulls, sea lions and the comic-book hero Professor Radium were all recruited to fight the threat of submarines during the First World War. But as John Campbell explains, it was Ernest Rutherford who led the way a century ago in using acoustics to deter these deadly craft.

  10. Rutherford Experiment

    CERN Multimedia

    This experiment, carried out by Ernest Rutherford in 1910, revolutionised understanding of the structure of matter, showing that almost all the mass of an atom is concentrated in a very small, positively charged nucleus. Alpha particles emitted at bombard a thin gold foil. A detector records the number of alpha particles crossing the foil per second. The number is displayed on the counter and updated every minute. Alpha particles are helium nuclei, they consist of 2 protons and 2 neutrons. Rotate the central knob to change the angle between the foil and the detector. The number of alpha particles detected depends on the angle. Most of the alpha particles travel straight through the foil because the gold atoms are mainly empty space. However some hit the atomic nucleus and are deflected.

  11. Spectrometry of the Rutherford backscattering of ions and the Raman scattering of light in GaS single crystals irradiated with 140-keV H{sub 2}{sup +} ions

    Energy Technology Data Exchange (ETDEWEB)

    Garibov, A. A.; Madatov, R. S., E-mail: msrahim@mail.ru [Azerbaijan National Academy of Sciences, Institute of Radiation Problems (Azerbaijan); Komarov, F. F.; Pilko, V. V. [Belarus State University, RTCCU of “Nanotechnology and Physical Electronics” (Belarus); Mustafayev, Yu. M.; Akhmedov, F. I.; Jakhangirov, M. M. [Azerbaijan National Academy of Sciences, Institute of Radiation Problems (Azerbaijan)

    2015-05-15

    The methods of the Raman scattering of light and Rutherford backscattering are used to study the degree of structural disorder in layered GaS crystals before and after irradiation with 140-keV H{sub 2}{sup +} ions. It is shown that the distribution of the crystal’s components over depth is homogeneous; for doses as high as 5 × 10{sup 15} cm{sup −2}, the stoichiometric composition of the compound’s components is retained. The experimental value of the critical dose for the beginning of amorphization amounts to about 5 × 10{sup 15} cm{sup −2} and is in accordance with the calculated value. The results obtained by the method of the Raman scattering of light confirm conservation of crystalline structure and the start of the amorphization process.

  12. Depth Dependence of Tetragonal Distortion of a ZnO/Mg_(0.1)Zn_(0.9)O/ZnO Heterostructure Studied by Rutherford Backscattering/Channeling

    Institute of Scientific and Technical Information of China (English)

    WANG Kun; DING Zhi-Bo; LI Lin; YAO Shu-De

    2009-01-01

    Rutherford backscattering and channeling are used to characterize the structure of a ZnO/Mg_(0.1) Zn_(0.9)O/ZnO heterostructure grown on a sapphire (0001) substrate by rf plasma-assisted molecular beam epitaxy.The results show that the Mg_(0.1)Zn_(0.9) O layer has the same hexagonal wurtzite structure as the underlying ZnO layer, and the heterostructure has a good crystalline quality with xmin=5%, which is the ratio of the backscattering yields of aligned and random spectra in the near-surface region.Using the channeling angular scan around an off-normal axis in the {1010} plane of both ZnO and MgZnO layer, the tetragonal distortion eT, which is caused by the elastic strain in the epilayer, is determined.The depth dependence of eT is obtained by using this technique.It can clearly be seen that the elastic strain rapidly decreases with the increase in thickness of the ZnO film in the early growth stage and becomes slightly larger in the region of the Mg_(0.1)Zn_(0.9)O layer.

  13. 4He和12C离子Rutherford背散射的Geant4模拟%Geant4-Based Simulation of 4 He and 12C Ions Rutherford Backscattering on Thin Films

    Institute of Scientific and Technical Information of China (English)

    王振超; 马玉刚; 杨海芳; 牛璐莹; 周庆; 赵广义; 宋明珠

    2013-01-01

    The Rutherford backscattering spectra (RBS) of 4 He and 12C normally incident on Au,Ag,Cu thin films at 270 keV and 500 keV were simulated via Geant4.Effects of different materials,thickness and energy of incident ions on RBS were discussed.The characters of 4He,12C RBS were analyzed.It was found that the mass resolution is much better for 12C RBS than that for 4He RBS.%利用Geant4程序模拟270,500 keV 4 He和12C离子垂直入射Au,Ag,Cu薄膜上的Rutherford背散射谱(RBS),并讨论材料、厚度和入射离子能量对背散射谱的影响.结果表明,能量较大的12C离子具有较好的质量分辨率.

  14. Analysis of forest backscattering characteristics based on polarization coherence tomography

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    It is difficult to make an inventory of vertical profiles of forest structure parameters in field measurements.However,analysis and understanding of forest backscattering characteristics contribute to estimation and detection of forest vertical structure because of the close relationships between backscattering characteristics and structure parameters.The vertical structure function in the complex interferometric coherence definition,which represents the vertical variation of microwave scattering with the penetration depth at a point in the 2-D radar image and can be used to analyze the forest backscattering characteristics,can be reconstructed from polarization coherence tomography(PCT).Based on PCT,the paper analyzes the forest backscattering characteristics and explores the inherent relationship between the result of PCT and the forest structure parameters from numerical simulation of Random Volume over Ground model(RVoG),Polarimetric SAR interferometry(PolInSAR)simulation of forest scene and PolInSAR data at L-band of the test site Traunstein.Firstly,the effects of the extinction coefficient and surface-to-volume scattering ratio in RVoG model on vertical backscattering characteristics are analyzed by means of numerical simulation.Secondly,by applying PCT to L-band POLInSAR simulations of forest scene,different variations of vertical backscattering due to different extinction coefficients and the ratios of surface-to-volume scattering resulting from different polarizations,forest types and densities are displayed and analyzed.Then a concept of relative average backscattering intensity is presented,and the factors which affect its vertical distribution are also discussed.Preliminary results show that there is high sensitivity of the vertical distribution of forest relative average backscattering intensity to the polarization,forest type and density.Finally,based on repeat pass DLR E-SAR L-band airborne POLInSAR data,the capability of PCT technology for detection

  15. RUTHERFORD B.HAYES

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    AFTER the scandals of Grant's administration the Republicans wanted an especially upright candidate; they found him in Rutherford B. Hayes, a devout, conscientious Ohioan whose Puritan ancestors had come from New England. In his third term as Governor of Ohio in 1876,

  16. Theoretical Analysis of Rayleigh Backscattering Noise in Fiber Raman Amplifiers

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In this paper, a new theoretical model for Rayleigh backscattering (RB) analysis of fiber Raman amplifiers is proposed. The model includes all the interactions among the pumps, signals, and all orders of RB. The results show that the higher order RB has a negligible influence on the performance of the amplifier. The co-propagating and counterpropagating RB power of the signal grow quadratically with the net-gain of the amplifier. The signal to double Rayleigh backscattering noise ratio (OSNRDRB ) of backward-pumped FRAs is better than that of the forward-pumped ones at high net-gain level (> 13 dB), while at low net-gain level the OSNRDrb of the forward-pumped FRAs is slightly better than that of the backward-pumped ones.

  17. Analysis of the quench propagation along Nb3Sn Rutherford cables with the THELMA code. Part II: application to the quench longitudinal propagation

    CERN Document Server

    Manfreda, G.; Bajas, H.; Perez, J.C.

    2016-01-01

    To improve the technology of the new generation of accelerator magnets, prototypes are being manufactured and tested in several laboratories. In parallel, many numerical analyses are being carried out to predict the magnets behaviour and interpret the experimental results. This paper focuses on the quench propagation velocity, which is a crucial parameter as regards the energy dissipation along the magnet conductor. The THELMA code, originally developed for cable-in-conduit conductors for fusion magnets, has been used to study such quench propagation. To this purpose, new code modules have been added to describe the Rutherford cable geometry, the material non-linear thermal properties and to describe the thermal conduction problem in transient regime. THELMA can describe the Rutherford cable at the strand level, modelling both the electrical and thermal contact resistances between strands and enabling the analysis of the effects of local hot spots and quench heaters. This paper describes the model application...

  18. Earnest Rutherford, the solution

    CERN Multimedia

    2003-01-01

    If you did not make it to the Science & Society talk by John Campbell last week and are still wondering about the spelling of "Earnest", here is the solution: Two months after the birth of his fourth child on 30 August 1871 in Spring Grove, New Zealand, James Rutherford registered his son, who was recorded as "Earnest" in the Birth Register. Presumably the Registrar wrote the name down as it sounded and the father failed to notice the mistake when signing the Register.

  19. Ernest Rutherford: scientist supreme

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J. [Physics Department, University of Canterbury, Christchurch (New Zealand)

    1998-09-01

    One hundred years ago this month, Ernest Rutherford a talented young New Zealander who had just spent three years as a postgraduate student in Britain left for Canada, where he was to do the work that won him a Nobel prize. All three countries can justifiably claim this great scientist as their own. Ernest Rutherford is one of the most illustrious scientists that the world has ever seen. He achieved enduring international fame because of an incredibly productive life, during which he altered our view of nature on three separate occasions. Combining brilliantly conceived experiments with much hard work and special insight, he explained the perplexing problem of naturally occurring radioactivity, determined the structure of the atom, and was the world's first successful alchemist, changing nitrogen into oxygen. Rutherford received a Nobel prize for the first discovery, but the other two would have been equally worthy candidates, had they been discovered by someone else. Indeed, any one of his other secondary achievements many of which are now almost forgotten would have been enough to bring fame to a lesser scientist. For example, he invented an electrical method for detecting individual ionizing radiations, he dated the age of the Earth, and briefly held the world record for the distance over which wireless waves could be detected. He predicted the existence of neutrons, he oversaw the development of large-scale particle accelerators, and, during the First World War, he led the allied research into the detection of submarines. In this article the author describes the life and times of Ernest Rutherford. (UK)

  20. Method for analysis of low energy backscattering spectra

    Energy Technology Data Exchange (ETDEWEB)

    Hnatowicz, V.; Kvitek, J. (Ceskoslovenska Akademie Ved, Rez. Ustav Jaderne Fyziky); Pelikan, L. (Ceske Vysoke Uceni Technicke, Prague (Czechoslavika). Dept. of Microelectronics); Rybka, V.; Krejci, P. (Tesla, Prague (Czechoslovakia))

    1982-04-15

    An analytical formula is proposed describing the shape of the energy spectra of particles backscattered from samples implanted with heavy impurities. The method is suitable for quantitative evaluation of backscattering spectra measured with low energy ions.

  1. Analysis of the quench propagation along Nb3Sn Rutherford cables with the THELMA code. Part I: geometric and thermal models

    CERN Document Server

    Manfreda, G.

    2016-01-01

    The paper describes the new lumped thermal model recently implemented in THELMA code for the coupled electromagnetic–thermal analysis of superconducting cables. A new geometrical model is also presented, which describes the Rutherford cables used for the accelerator magnets. A first validation of these models has been given by the analysis of the quench longitudinal propagation velocity in the Nb3Sn prototype coil SMC3, built and tested in the frame of the EUCARD project for the development of high field magnets for LHC machine. This paper shows in detail the models, while their application to the quench propagation analysis is presented in a companion paper.

  2. Strong Localization in Disordered Media: Analysis of the Backscattering Cone

    KAUST Repository

    Delgado, Edgar

    2012-06-01

    A very interesting effect in light propagation through a disordered system is Anderson localization of light, this phenomenon emerges as the result of multiple scattering of waves by electric inhomogeneities like spatial variations of index of refraction; as the amount of scattering is increased, light propagation is converted from quasi-diffusive to exponentially localized, with photons confined in a limited spatial region characterized by a fundamental quantity known as localization length. Light localization is strongly related to another interference phenomenon emerged from the multiple scattering effect: the coherent backscattering effect. In multiple scattering of waves, in fact, coherence is preserved in the backscattering direction and produces a reinforcement of the field flux originating an observable peak in the backscattered intensity, known as backscattering cone. The study of this peak provide quantitative information about the transport properties of light in the material. In this thesis we report a complete FDTD ab-initio study of light localization and coherent backscattering. In particular, we consider a supercontinuum pulse impinging on a sample composed of randomly positioned scatterers. We study coherent backscattering by averaging over several realizations of the sample properties. We study then the coherent backscattering cone properties as the relative permittivity of the sample is changed, relating the latter with the light localization inside the sample. We demonstrate important relationships between the width of the backscattering cone and the localization length, which shows a linear proportionality in the strong localization regime.

  3. Analysis of the quench propagation along Nb3Sn Rutherford cables with the THELMA code. Part II: Model predictions and comparison with experimental results

    Science.gov (United States)

    Manfreda, G.; Bellina, F.; Bajas, H.; Perez, J. C.

    2016-12-01

    To improve the technology of the new generation of accelerator magnets, prototypes are being manufactured and tested in several laboratories. In parallel, many numerical analyses are being carried out to predict the magnets behaviour and interpret the experimental results. This paper focuses on the quench propagation velocity, which is a crucial parameter as regards the energy dissipation along the magnet conductor. The THELMA code, originally developed for cable-in-conduit conductors for fusion magnets, has been used to study such quench propagation. To this purpose, new code modules have been added to describe the Rutherford cable geometry, the material non-linear thermal properties and to describe the thermal conduction problem in transient regime. THELMA can describe the Rutherford cable at the strand level, modelling both the electrical and thermal contact resistances between strands and enabling the analysis of the effects of local hot spots and quench heaters. This paper describes the model application to a sample of Short Model Coil tested at CERN: a comparison is made between the experimental results and the model prediction, showing a good agreement. A comparison is also made with the prediction of the most common analytical models, which give large inaccuracies when dealing with low n-index cables like Nb3Sn cables.

  4. Complementary use of ion beam elastic backscattering and recoil detection analysis for the precise determination of the composition of thin films made of light elements

    Energy Technology Data Exchange (ETDEWEB)

    Climent-Font, A. [Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain); Centro de Micro-Analisis de Materiales (CMAM), Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain)], E-mail: acf@uam.es; Cervera, M.; Hernandez, M.J. [Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain); Laboratorio de Microelectronica, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain); Munoz-Martin, A. [Centro de Micro-Analisis de Materiales (CMAM), Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain); Piqueras, J. [Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain); Laboratorio de Microelectronica, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain)

    2008-04-15

    Rutherford backscattering spectrometry (RBS) is a well known powerful technique to obtain depth profiles of the constituent elements in a thin film deposited on a substrate made of lighter elements. In its standard use the probing beam is typically 2 MeV He. Its capabilities to obtain precise composition profiles are severely diminished when the overlaying film is made of elements lighter than the substrate. In this situation the analysis of the energy of the recoiled element from the sample in the elastic scattering event, the ERDA technique may be advantageous. For the detection of light elements it is also possible to use beams at specific energies producing elastic resonances with these light elements to be analyzed, with a much higher scattering cross sections than the Rutherford values. This technique may be called non-RBS. In this work we report on the complementary use of ERDA with a 30 MeV Cl beam and non-RBS with 1756 keV H ions to characterize thin films made of boron, carbon and nitrogen (BCN) deposited on Si substrates.

  5. 27 CFR 9.133 - Rutherford.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Rutherford. 9.133 Section... Rutherford. (a) Name. The name of the viticultural area described in this section is “Rutherford.” (b) Approved maps. The appropriate maps for determining the boundary of the Rutherford viticultural area...

  6. A Rutherford Scattering Simulation with Microcomputer Graphics.

    Science.gov (United States)

    Calle, Carlos I.; Wright, Lavonia F.

    1989-01-01

    Lists a program for a simulation of Rutherford's gold foil experiment in BASIC for both Apple II and IBM compatible computers. Compares Rutherford's model of the atom with Thompson's plum pudding model of the atom. (MVL)

  7. Quantitative Analysis of Venus Radar Backscatter Data in ArcGIS

    Science.gov (United States)

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

    2005-01-01

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

  8. The Spatial Distribution and Morphology of Supported Nanocatalysts using Rutherford-Scattered Electron Imaging

    Science.gov (United States)

    Gai, Pratibha; Midgley, Paul; Weyland, Matthew; Thomas, John; Boyes, Edward

    2003-03-01

    Back-scattered electron (BSE) imaging, combined with scanning transmission electron microscopic (STEM) high angle annular dark field (HAADF) imaging, both using Rutherford-scattered electrons, are ideal in recording images of supported nanocatalysts. The incoherent scattering process ensures that images are ideal for electron tomography and the reconstruction of three-dimensional (3D) nanocatalyst distribution such as Pd on carbon.

  9. A Strange Box and a Stubborn Brit: Rutherford's Experiments with Alpha Particles.

    Science.gov (United States)

    Digilov, M.

    1991-01-01

    Discusses 5 innovative experiments conducted by Rutherford in early 1900s utilizing the 30 milligrams of radium salt he personally carried from Europe to Canada in 1903. Traces his work with alpha particles from his original results which determined their nature, charge, and mass, to his technique of backscattering which helped to advance…

  10. Rutherford, Maestro of the Atom

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, John (University of Canterbury, New Zealand)

    2003-12-10

    This talk will cover some of the lesser known aspects of Rutherford's work, including his early work in wireless signaling and his later encouragement of radio studies of the ionosphere, the development of what was later improved to be now called the Geiger-Muller tube, his acoustic work for submarine detection during the First World War, the development of particle accelerators and the race to splitting the atom, the first use of coincidence detectors, and why he received just one Nobel Prize.

  11. Backscattering analysis of high frequency ultrasonic imaging for ultrasound-guided breast biopsy

    Science.gov (United States)

    Cummins, Thomas; Akiyama, Takahiro; Lee, Changyang; Martin, Sue E.; Shung, K. Kirk

    2017-03-01

    A new ultrasound-guided breast biopsy technique is proposed. The technique utilizes conventional ultrasound guidance coupled with a high frequency embedded ultrasound array located within the biopsy needle to improve the accuracy in breast cancer diagnosis.1 The array within the needle is intended to be used to detect micro- calcifications indicative of early breast cancers such as ductal carcinoma in situ (DCIS). Backscattering analysis has the potential to characterize tissues to improve localization of lesions. This paper describes initial results of the application of backscattering analysis of breast biopsy tissue specimens and shows the usefulness of high frequency ultrasound for the new biopsy related technique. Ultrasound echoes of ex-vivo breast biopsy tissue specimens were acquired by using a single-element transducer with a bandwidth from 41 MHz to 88 MHz utilizing a UBM methodology, and the backscattering coefficients were calculated. These values as well as B-mode image data were mapped in 2D and matched with each pathology image for the identification of tissue type for the comparison to the pathology images corresponding to each plane. Microcalcifications were significantly distinguished from normal tissue. Adenocarcinoma was also successfully differentiated from adipose tissue. These results indicate that backscattering analysis is able to quantitatively distinguish tissues into normal and abnormal, which should help radiologists locate abnormal areas during the proposed ultrasound-guided breast biopsy with high frequency ultrasound.

  12. Rutherford's curriculum vitae, 1894-1907.

    Science.gov (United States)

    Cohen, M

    1995-06-01

    A single page, handwritten document was discovered when the Macdonald Physics building of McGill University in Montreal was gutted in 1978. This proved to be the draft of Ernest Rutherford's curriculum vitae (C.V.) covering the years 1894-1907, probably written in the autumn of 1906 when Rutherford was preparing to leave McGill. The C.V. contains 21 headings in chronological order, referring to research and other activities of Rutherford and his coauthors (especially Soddy and Barnes), plus a further set of headings relating to the associated investigations of Rutherford's team, including Eve and Hahn. A transcript of the document is provided, although in several places, Rutherford's handwriting is difficult to interpret, and the significance of his abbreviations is not always clear. Each of the items in the C.V. is discussed briefly in this review, in the light both of Rutherford's personal career and of the contribution of his team to the development and understanding of radioactivity. This contribution included the cause and nature of radioactivity (with Soddy), energy aspects of radioactive decay (with Barnes), elucidation of the uranium-radium, thorium and actinium series (Godlewski and Hahn), the radioactivity of the earth and atmosphere (Eve), the nature of the gamma rays (Eve) and, perhaps most important of all, the nature and properties of the alpha particle (Rutherford himself). The latter investigations led directly to Rutherford's later work in Manchester, including the nuclear model of the atom and artificial disintegration of the nucleus.

  13. An application of the multibeam sounder for seabed backscattering analysis

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Raju, Y.S.N.

    A theoretical analysis of vertical farfield pattern for a multibeam sounder is performed. The farfield pattern for different steered angles establish the usefulness of present multibeam arrays. An interaction effect of different steered multibeam...

  14. Spectral analysis, digital integration, and measurement of low backscatter in coherent laser radar

    Science.gov (United States)

    Vaughan, J. M.; Callan, R. D.; Bowdle, D. A.; Rothermel, J.

    1989-01-01

    A method of surface acoustic wave (SAW) spectral analysis and digital integration that has been used previously in coherent CW laser work with CO2 lasers at 10.6 microns is described. Expressions are derived for the signal to noise ratio in the measured voltage spectrum with an approximation for the general case and rigorous treatment for the low signal case. The atmospheric backscatter data accumulated by the airborne LATAS (laser true airspeed) coherent laser radar system are analyzed.

  15. Analysis of multi-layer ERBS spectra

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-15

    Highlights: • Electron Rutherford backscattering (ERBS) spectra are presented. • The spectra are fitted based on physical meaningful quantities. • Very consistent results are obtained for spectra taken under different conditions. • This establishes that ERBS can be used to measure film thicknesses. - Abstract: A systematic way of analysis of multi-layer electron Rutherford backscattering spectra is described. The approach uses fitting in terms of physical meaningful parameters. Simultaneous analysis then becomes possible for spectra taken at different incoming energies and measurement geometries. Examples are given to demonstrate the level of detail that can be resolved by this technique.

  16. AN ANALYSIS OF THE MICROSTRUCTURE CHARACTERISTICS IN HUMAN KIDNEY WITH ULTRASONIC BACKSCATTERING

    Institute of Scientific and Technical Information of China (English)

    Yan Bige; Ta Dean; Wang Rong

    2005-01-01

    Objective To investigate the microstructure characteristics in human kidney with the WD cepstrum of ultrasonic backscattering. Methods By using this method, an analysis of the backscattering signals of normal and pathological human kidney in vitro was made and the mean spacing of the scatterers of biological soft tissues was estimated, then compared the means of this new approach with the means of the AR cepstrum. Results The results show that the mean spacings of the scatterers of the two different kidney tissues are noticeably different, which reveals the fact that the WD cepstrum works more effective than the AR cepstrum in showing the features of the microstructure of soft tissues. Conclusion The WD cepstrum is an effective mean to analyze the ultrasonic scattering signals and determine the features of the mean spacing of the scatterers of soft tissues. This method provides more available clinical diagnosis and improves the results of mean spacing of the scatterers of soft tissues.

  17. Thin film depth profiling using simultaneous particle backscattering and nuclear resonance profiling

    Science.gov (United States)

    Barradas, N. P.; Mateus, R.; Fonseca, M.; Reis, M. A.; Lorenz, K.; Vickridge, I.

    2010-06-01

    We report an important extension to the DataFurnace code for Ion Beam Analysis which allows users to simultaneously and self-consistently analyse Rutherford (RBS) or non-Rutherford (EBS) elastic backscattering together with particle-induced gamma-ray (PIGE) spectra. We show that the code works correctly with a well-known sample. Previously it has not been feasible to self-consistently treat PIGE and RBS/EBS data to extract the depth profiles. The PIGE data can be supplied to the code in the usual way as counts versus beam energy, but the differential cross-sections for the PIGE reaction are required. We also compared the results obtained by the new routine with high resolution narrow resonance profiling (NRP) simulations obtained with the stochastic model of energy loss.

  18. Phase analysis on dual-phase steel using band slope of electron backscatter diffraction pattern.

    Science.gov (United States)

    Kang, Jun-Yun; Park, Seong-Jun; Moon, Man-Been

    2013-08-01

    A quantitative and automated phase analysis of dual-phase (DP) steel using electron backscatter diffraction (EBSD) was attempted. A ferrite-martensite DP microstructure was produced by intercritical annealing and quenching. An EBSD map of the microstructure was obtained and post-processed for phase discrimination. Band slope (BS), which was a measure of pattern quality, exhibited much stronger phase contrast than another conventional one, band contrast. Owing to high sensitivity to lattice defect and little orientation dependence, BS provided handiness in finding a threshold for phase discrimination. Its grain average gave a superior result on the discrimination and volume fraction measurement of the constituent phases in the DP steel.

  19. A continuum model for current distribution in Rutherford cables

    CERN Document Server

    Akhmedov, A I; Breschi, M

    2001-01-01

    An analysis of eddy currents induced in flat Rutherford-type cables by external time dependent magnetic fields has been performed. The induced currents generate in turn a secondary magnetic field which has a longitudinal periodicity (periodic pattern). The dependence of the amplitude of the pattern on the history of the cable excitation has been investigated. The study has been carried out with two different models for the simulation of current distribution in Rutherford cables, namely a network model, based on a lumped parameters circuit and a "continuum" model, based on a distributed parameters circuit. We show the results of simulations of the current distribution in the inner cable of a short LHC dipole model in different powering conditions and compare them to experimental data. (12 refs).

  20. Infrared reflectometry of skin: Analysis of backscattered light from different skin layers

    Science.gov (United States)

    Pleitez, Miguel A.; Hertzberg, Otto; Bauer, Alexander; Lieblein, Tobias; Glasmacher, Mathias; Tholl, Hans; Mäntele, Werner

    2017-09-01

    We have recently reported infrared spectroscopy of human skin in vivo using quantum cascade laser excitation and photoacoustic or photothermal detection for non-invasive glucose measurement . Here, we analyze the IR light diffusely reflected from skin layers for spectral contributions of glucose. Excitation of human skin by an external cavity tunable quantum cascade laser in the spectral region from 1000 to 1245 cm- 1, where glucose exhibits a fingerprint absorption, yields reflectance spectra with some contributions from glucose molecules. A simple three-layer model of skin was used to calculate the scattering intensities from the surface and from shallow and deeper layers using the Boltzmann radiation transfer equation. Backscattering of light at wavelengths around 10 μm from the living skin occurs mostly from the Stratum corneum top layers and the shallow layers of the living epidermis. The analysis of the polarization of the backscattered light confirms this calculation. Polarization is essentially unchanged; only a very small fraction (skin would have the drawback that only shallow layers containing some glucose at concentrations only weakly related to blood glucose are monitored.

  1. Rutherford, Radioactivity, and the Atomic Nucleus

    CERN Document Server

    Kragh, Helge

    2012-01-01

    Modern atomic and nuclear physics took its start in the early part of the twentieth century, to a large extent based upon experimental investigations of radioactive phenomena. Foremost among the pioneers of the new kind of physics was Ernest Rutherford, who made fundamental contributions to the structure of matter for more than three decades and, in addition, founded important research schools in Manchester and Cambridge. This paper reviews the most important aspects of Rutherford's scientific work in the period from about 1900 to 1920, and it also refers to some of his last experiments of the 1930s. The emphasis is on his theory of radioactive disintegration (1902), the discovery of the atomic nucleus (1911), and the first artificially produced element transformation (1919). Following the transmutation experiments, Rutherford developed elaborate models of the atomic nucleus, but these turned out to be unsuccessful. Other subjects could be included, but the three mentioned are undoubtedly those of the greates...

  2. Transfer matrix analysis of backscattering and reflection effects on WDM-PON systems.

    Science.gov (United States)

    Simatupang, Joni Welman; Lee, San-Liang

    2013-11-18

    This paper proposes using power transfer matrix analysis to characterize the effects of Rayleigh backscattering and Fresnel reflection on WDM-PON systems. The modeling of a WDM-PON system can be carried out simply by matrix multiplication of the corresponding matrices for all the building blocks, where all possible guided backward lights and resonant configurations along the optical network can be accounted for. The total sum of all interferences affecting the bidirectional transmission that leads to an optical crosstalk-to-signal (C/S) ratio can be modeled as back-reflections through cascaded two-port networks for the downstream and upstream signals. This approach is simple, robust, efficient, and also accurate. Its accuracy is verified for simple system architectures and then applied to study more complicated cases. The results show its versatility to analyze a wide variety of bidirectional optical transmission systems.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-05-10

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

  4. A Multivariate Correlation Analysis of High- Frequency Bottom Backscattering Strength Measurements With Geotechnical Parameters

    NARCIS (Netherlands)

    Simons, D.G.; Snellen, M.; Ainslie, M.A.

    2007-01-01

    Sound backscattered from the seabed has been measured in a 10x10-nmi2 region of the North Sea, characterized by a variety of bottom types, including mud, sand, and gravel. The backscattering strength measurements are made by a forward- looking sonar, operating at 100 kHz and tilted at an angle of 30

  5. A multivariate correlation analysis of high-frequency bottom backscattering strength measurements with geotechnical parameters

    NARCIS (Netherlands)

    Simons, D.G.; Snellen, M.; Ainslie, M.A.

    2007-01-01

    Sound backscattered from the seabed has been measured in a 10 × 10-nmi2 region of the North Sea, characterized by a variety of bottom types, including mud, sand, and gravel. The backscattering strength measurements are made by a forward-looking sonar, operating at 100 kHz and tilted at an angle of 3

  6. A Multivariate Correlation Analysis of High- Frequency Bottom Backscattering Strength Measurements With Geotechnical Parameters

    OpenAIRE

    2007-01-01

    Sound backscattered from the seabed has been measured in a 10x10-nmi2 region of the North Sea, characterized by a variety of bottom types, including mud, sand, and gravel. The backscattering strength measurements are made by a forward- looking sonar, operating at 100 kHz and tilted at an angle of 30 from the horizontal. Fifty bottom-grab samples, representative of the uppermost 20 cm, were taken and analyzed for gravel content, shell content, and grain-size distribution. The backscatter measu...

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-11-15

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

  9. Quantitative analysis of martensite and bainite microstructures using electron backscatter diffraction.

    Science.gov (United States)

    Wang, Yongzhe; Hua, Jiajie; Kong, Mingguang; Zeng, Yi; Liu, Junliang; Liu, Ziwei

    2016-09-01

    In the present work, ultra-high-strength steels with multiphase microstructures containing martensite and bainite were prepared by controlling the cooling rate. A new approach was proposed for quantitatively statistical phase analysis using electron backscatter diffraction (EBSD) based on the band contrast which correlates to the quality and intensity of the diffraction patterns. This approach takes advantage of the inherently greater lattice imperfections of martensite, such as dislocations and low-angle grain boundaries, relative to that of bainite. These can reduce the intensity and quality of the EBSD patterns of martensite, which decrease the band contrast. Thus, combined with morphological observations, Gaussian two-peak fitting was employed to analyze the band contrast profile and confirm the ranges of band contrast for the two phases. The volume fractions of bainite and martensite in different samples were determined successfully. In addition, the results show that increased cooling rates improve the proportion of martensite and the ratio of martensite to bainite. Microsc. Res. Tech. 79:814-819, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. Automatic backscatter analysis of regional left ventricular systolic function using color kinesis.

    Science.gov (United States)

    Schwartz, S L; Cao, Q L; Vannan, M A; Pandian, N G

    1996-06-15

    Assessment of regional wall motion by 2-dimensional echocardiography can be performed by either semiquantitative wall motion scoring or by quantitative analysis. The former is subjective and requires expertise. Quantitative methods are too time-consuming for routine use in a busy clinical laboratory. Color kinesis is a new algorithm utilizing acoustic backscatter analysis. It provides a color encoded map of endocardial motion in real time. In each frame a new color layer is added; the thickness of the color beam represents endocardial motion during that frame. The end-systolic image has multiple color layers, representing regional and temporal heterogeneity of segmental motion. The purpose of this study was to validate the use of color kinesis for semiquantitative analysis of regional left ventricular systolic function and quantitatively in measurement of endocardial excursion. Semiquantitative wall motion scoring was performed in 18 patients using both 2-dimensional echo and color kinesis. Scoring was identical in 74% of segments; there was 84% agreement in definition of normal vs. abnormal. There was less interobserver variability in wall motion scoring using color kinesis. Endocardial excursion was quantified in 21 patients. 70% of the imaged segments were suitable for analysis. Correlation between 2-dimensional echocardiographic measurements and color kinesis was excellent, r = 0.87. The mean difference in excursion as measured by the 2 methods was -0.05 +/- 2.0 mm. In conclusion, color kinesis is a useful method for assessing regional contraction by displaying a color map of systolic endocardial excursion. This algorithm may improve the confidence and accuracy of assessment of segmental ventricular function by echocardiographic methods.

  11. Quantitative evaluation of myocardial fibrosis by cardiac integrated backscatter analysis in Kawasaki disease.

    Science.gov (United States)

    Xie, Lijian; Wang, Renjian; Huang, Min; Zhang, Yongwei; Shen, Jie; Xiao, Tingting

    2016-01-12

    Kawasaki disease is an acute, systemic vasculitis that affects the coronary arteries. However, the relationship between myocardial fibrosis and Kawasaki disease has been completely unknown until now. We aimed to provide quantitative information about myocardial fibrosis using cardiac integrated backscatter in Han race Kawasaki disease patients. Ninety Kawasaki disease patients and 90 healthy control subjects were recruited. Based on Kawasaki disease status, the patients were categorized into 3 groups: acute, subacute, and convalescence phase. Based on coronary artery status, the Kawasaki disease patients were categorized into 3 groups: without coronary artery lesions, with coronary artery dilation, and with coronary artery aneurysms. All subjects underwent two-dimensional and Doppler examinations to measure clinical echocardiographic parameters. Myocardial fibrosis was detected with calibrated integrated backscatter imaging. Left ventricle systolic functions were normal in both the Kawasaki disease and control participants. The myocardial calibrated integrated backscatter values of the left ventricles of the acute (p Kawasaki disease patients were significantly greater than those of the healthy controls. The left ventricle myocardial calibrated integrated backscatter values were significantly smaller in the Kawasaki disease patients without coronary artery lesions than in the Kawasaki disease patients with coronary artery dilations and coronary artery aneurysms in different phases. The left ventricle myocardial calibrated integrated backscatter results were positively correlated with coronary artery status in the acute (r = 0.331, p Kawasaki disease. Our findings may suggest that myocardial fibrosis occurs during early episodes of Kawasaki disease given uncertainties that exist regarding correlations of calibrated integrated backscatter and myocardial fibrosis.

  12. Super-resolved time-frequency analysis of wideband backscattered data

    DEFF Research Database (Denmark)

    Moore, John; Ling, H.

    1995-01-01

    A time-frequency super-resolution procedure is presented for processing wideband backscattered data containing both scattering center and natural resonance information. In this procedure, Prony's method is first applied in the frequency domain to locate scattering centers. The data is processed one...

  13. Photonic Rutherford Scattering: A Classical and Quantum Mechanical Analogy in Ray- and Wave-Optics

    CERN Document Server

    Selmke, Markus

    2012-01-01

    Using Fermat's least optical path principle the family of ray-trajectories through a special but common type of a gradient refractive index lens, n(r)=n_0+\\Delta n R/r, is solved analytically. The solution, i.e. the ray-equation r(phi), is shown to be closely related to the famous Rutherford scattering and therefore termed photonic Rutherford scattering. It is shown that not only do these classical limits correspond, but also the wave-mechanical pictures coincide: The time-independent Schr\\"odingier equation and the inhomogeneous Helmholz equation permit the same mapping between massive particle scattering and diffracted optical scalar waves. Scattering of narrow wave-packets finally recovers the classical trajectories. The analysis suggests that photothermal single particle microscopy infact measures photonic Rutherford scattering in specific limits.

  14. Analysis of the eight-year trend in ozone depletion from empirical models of solar backscattered ultraviolet instrument degradation

    Science.gov (United States)

    Herman, J. R.; Hudson, R. D.; Serafino, G.

    1990-01-01

    Arguments are presented showing that the basic empirical model of the solar backscatter UV (SBUV) instrument degradation used by Cebula et al. (1988) in their analysis of the SBUV data is likely to lead to an incorrect estimate of the ozone trend. A correction factor is given as a function of time and altitude that brings the SBUV data into approximate agreement with the SAGE, SME, and Dobson network ozone trends. It is suggested that the currently archived SBUV ozone data should be used with caution for periods of analysis exceeding 1 yr, since it is likely that the yearly decreases contained in the archived data are too large.

  15. Analysis of dose and risk associated with the use of backscatter vans

    Energy Technology Data Exchange (ETDEWEB)

    Correa, Samanda C.A.; Aquino, Josilto O., E-mail: scorrea@cnen.gov.b, E-mail: josilto@cnen.gov.b [Comissao Nacional de Energia Nuclear (DIAPI/CGMI/CNEN), Rio de Janeiro, RJ (Brazil). Coordenacao Geral de Instalacoes Medicas e Industriais. Div. de Aplicacoes Industriais; Souza, Edmilson M., E-mail: emonteiro@nuclear.ufrj.b [Centro Universitario Estadual da Zona Oeste (CAPI/UEZO), Rio de Janeiro, RJ (Brazil); Silva, Ademir X., E-mail: ademir@con.ufrj.b [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

    2011-07-01

    In recent years, imaging technology using radiation has been gaining in importance for the screening of persons for security reasons and in order to detect contraband. And currently, new X-ray detection technologies have been introduced such as the Backscatter Van. The Backscatter Van is used in port and border security, force protection, urban surveillance, and other critical security applications in order to seize drugs, explosives, and more. The system is mobile, affordable and the faster, more effective, and less expensive than any mobile screening solution in the marketplace. However, although the application of this equipment in the national security area is indeed relevant, its use has caused a great deal of controversy, especially with regard to the doses absorbed and to the cancer induction risk associated with these exposures. The aim of this study is to use the Monte Carlo MCNPX code and the male adult voxel (MAX) and female adult voxel (FAX) phantoms, to evaluate the absorbed dose, effective dose and cancer induction risk values associated with the exposures of individuals submitted to Backscatter Van. The effective dose values were calculated as recommended by the new ICRP 103 and the cancer induction risk values were estimated through the BEIR VII document. (author)

  16. Secret in the Margins: Rutherford's Gold Foil Experiment

    Science.gov (United States)

    Aydin, Sevgi; Hanuscin, Deborah L.

    2011-01-01

    In this article, the authors describe a lesson that uses the 5E Learning Cycle to help students not only understand the atomic model but also how Ernest Rutherford helped develop it. The lesson uses Rutherford's gold foil experiment to focus on three aspects of the nature of science: the empirical nature of science, the tentativeness of scientific…

  17. PREFACE: Rutherford Centennial Conference on Nuclear Physics

    Science.gov (United States)

    Freeman, Sean

    2012-09-01

    Just over one hundred years ago, Ernest Rutherford presented an interpretation of alpha-particle scattering experiments, performed a couple of years earlier by Geiger and Marsden, to the Manchester Literary and Philosophical Society. The work was summarised shortly afterwards in a paper in the Philosophical Magazine. He postulated that a dense speck of matter must exist at the centre of an atom (later to become known as the nucleus) if the details of the experiments, particularly the yield of alpha particles scattered through large angles, were to be explained. The nuclear hypothesis, combined with the experimental work by Moseley on X-rays and Bohr's theoretical ideas, both also initiated at the Victoria University of Manchester, established our view of atomic structure and gave birth to the field of nuclear physics. The Rutherford Centennial Conference on Nuclear Physics was held at The University of Manchester in August 2011 to celebrate this anniversary by addressing the wide range of contemporary topics that characterise modern nuclear physics. This set of proceedings covers areas including nuclear structure and astrophysics, hadron structure and spectroscopy, fundamental interactions studied within the nucleus and results of relativistic heavy-ion collisions. We would like to thank all those who presented their recent research results at the conference; the proceedings stand as a testament to the excitement and interest that still pervades the pursuit of this field of physics. We would also like to thank those who contributed in other ways to the conference. To colleagues at the Manchester Museum of Science and Industry for putting together an exhibition to coincide with the conference that included the manuscript of the 1911 paper, letters, notebooks and equipment used by Rutherford. These items were kindly loaned by Cambridge and Manchester Universities. Winton Capital generously supported this exhibition. We would also like to thank Professor Mary Fowler

  18. Time evolution analysis of the electron distribution in Thomson/Compton back-scattering

    Energy Technology Data Exchange (ETDEWEB)

    Petrillo, V.; Bacci, A.; Curatolo, C.; Maroli, C.; Serafini, L.; Rossi, A. R. [INFN-Universitá degli Studi Milano, Via Celoria, 16 20133 Milano (Italy)

    2013-07-28

    We present the time evolution of the energy distribution of a relativistic electron beam after the Compton back-scattering with a counter-propagating laser field, performed in the framework of the Quantum Electrodynamics, by means of the code CAIN. As the correct angular distribution of the spontaneous emission is accounted, the main effect is the formation of few stripes, followed by the diffusion of the more energetic particles toward lower values in the longitudinal phase space. The Chapman-Kolmogorov master equation gives results in striking agreement with the numerical ones. An experiment on the Thomson source at SPARC-LAB is proposed.

  19. Time evolution analysis of the electron distribution in Thomson/Compton back-scattering

    Science.gov (United States)

    Petrillo, V.; Bacci, A.; Curatolo, C.; Maroli, C.; Serafini, L.; Rossi, A. R.

    2013-07-01

    We present the time evolution of the energy distribution of a relativistic electron beam after the Compton back-scattering with a counter-propagating laser field, performed in the framework of the Quantum Electrodynamics, by means of the code CAIN. As the correct angular distribution of the spontaneous emission is accounted, the main effect is the formation of few stripes, followed by the diffusion of the more energetic particles toward lower values in the longitudinal phase space. The Chapman-Kolmogorov master equation gives results in striking agreement with the numerical ones. An experiment on the Thomson source at SPARC-LAB is proposed.

  20. Theoretical analysis on double Rayleigh backscattering noise in optical fibre Raman amplifiers and its suppression

    Institute of Scientific and Technical Information of China (English)

    Jiang Wen-Ning; Chen Jian-Ping; Li Xin-Wan; Shang Tao

    2004-01-01

    In this paper, amplified double Rayleigh backscattering noise (DRB) in the optical fibre Raman amplifier is analysed. Expressions are presented for both forward pumping and backward pumping schemes. Calculation is performed to show the effective suppression of DRB noise by employing an optical isolator. The optimal position for the isolator is determined and is found to be insensitive to the power levels of the signals and pumps. The results show that a reduction of the DRB noise by almost 2 to 3 orders can be reached.

  1. CERN celebrates the ‘Rutherford centenary’

    CERN Multimedia

    Maximilien Brice

    2011-01-01

    CERN marked the centenary of the discovery of the atomic nucleus, as published in Ernest Rutherford’s famous paper of 1911, with its Rutherford Centennial Colloquium, held on 15 November in the presence of John Adank, New Zealand’s ambassador to the World Trade Organization in Geneva. After an introduction by CERN’s director-general, Rolf Heuer, the speakers covered topics ranging from Rutherford’s early life in New Zealand, presented by his great grand-daughter Mary Fowler, through to his role as an inspiration to young scientists in his homeland, as seen by New Zealander Mark Kruse, who is now at Duke University and a member of the ATLAS collaboration. Fellow New Zealander, John Campbell, spoke about Rutherford’s road to discovery of the nuclear atom. Rutherford’s scientific legacy in nuclear physics was covered by Sean Freeman, appropriately from Manchester University, where the famous scattering experiment took place. Jerome Friedman delved deeper into matter with his talk detailing the scatt...

  2. Metallographic preparation of Zn-21Al-2Cu alloy for analysis by electron backscatter diffraction (EBSD).

    Science.gov (United States)

    Rodríguez-Hernández, M G; Martínez-Flores, E E; Torres-Villaseñor, G; Escalera, M Dolores

    2014-08-01

    Samples of Zn-21Al-2Cu alloy (Zinalco) that will be heavily deformed were prepared using five different manual mechanical metallographic methods. Samples were analyzed before tensile testing using the orientation imaging microscopy-electron backscatter diffraction (OIM-EBSD) technique. The effect of type and particle size during the final polishing stages for this material were studied in order to identify a method that produces a flat, damage free surface with a roughness of about 50 nm and clean from oxide layers, thereby producing diffraction patterns with high image quality (IQ) and adequate confidence indexes (CI). Our results show that final polishing with alumina and silica, as was previously suggested by other research groups for alloys that are difficult to prepare or alloys with low melting point, are not suitable for manual metallographic preparation of this alloy. Indexes of IQ and CI can be used to evaluate methods of metallographic preparation of samples studied using the OIM-EBSD technique.

  3. Electron Backscatter Diffraction Analysis of Inconel 718 Parts Fabricated by Selective Laser Melting Additive Manufacturing

    Science.gov (United States)

    Wang, Xiaoqing; Chou, Kevin

    2017-02-01

    In this study, the crystallographic texture of an Inconel 718 part fabricated by selective laser melting was investigated. The front surface (X-Z plane) microstructure is characterized by the columnar grains growing along the build direction, and the width of columnar grains is in the range of about 75-150 µm, with the bottom layers having narrower grains as a result of a higher cooling rate. In addition to equiaxed grains, the top surface (X-Y plane) has a feature of patch patterns resulting from the laser scanning strategy. Based on the electron backscatter diffraction results, there appears only weak crystallographic texture in both the X-Z plane and the X-Y plane of the part. From the grain boundary map, the microstructures are composed of high-angle boundaries with a larger fraction of subgrain boundaries.

  4. Analysis of Orange Peel Defect in St14 Steel Sheet by Electron Backscattered Diffraction (EBSD)

    Institute of Scientific and Technical Information of China (English)

    Shengquan CAO; Jinxu ZHANG; Jiansheng WU; Jiaguang CHEN

    2005-01-01

    In this paper, the orange peel defect in the surface range of the st14 steel sheet has been investigated using the electron backscattered diffraction (EBSD) technique. It has been found that the orange peel defect in the st14steel sheet was resulted from the local coarse grains which were produced during hot-rolling due to the critical deformation in dual-phase zone. During deep drawing, the coarse grains with {100}<001> microtexture can slip on the {112}<111> slip system to form bulging and yields orange peel defects, while the coarse grains with {112}<110>orientation do not form the defect as the Schmid factor of {112}<111> slip system in it equals zero.

  5. Electron Backscatter Diffraction Analysis of Inconel 718 Parts Fabricated by Selective Laser Melting Additive Manufacturing

    Science.gov (United States)

    Wang, Xiaoqing; Chou, Kevin

    2016-11-01

    In this study, the crystallographic texture of an Inconel 718 part fabricated by selective laser melting was investigated. The front surface (X-Z plane) microstructure is characterized by the columnar grains growing along the build direction, and the width of columnar grains is in the range of about 75-150 µm, with the bottom layers having narrower grains as a result of a higher cooling rate. In addition to equiaxed grains, the top surface (X-Y plane) has a feature of patch patterns resulting from the laser scanning strategy. Based on the electron backscatter diffraction results, there appears only weak crystallographic texture in both the X-Z plane and the X-Y plane of the part. From the grain boundary map, the microstructures are composed of high-angle boundaries with a larger fraction of subgrain boundaries.

  6. Improved angular resolution in electron backscatter diffraction analysis by use of image correlation techniques

    Institute of Scientific and Technical Information of China (English)

    CUI HY; Andrew GODFREY; WANG W

    2008-01-01

    In this paper we describe a method for improving the angular resolution of the electron backscatter diffraction(EBSD)technique based on a correlative matching of EBSD patterns.Standard image interpolation methods are used to detect shifts between selected regions of the EBSD patterns to an accuracy of one tenth of a pixel.Simulated data sets are used to show that such accuracy,combined with a small angle approximation in calculation of the rotation angle,allows determination of the misorientation between patterns to an accuracy of 0.01 degrees.The method is tested on samples of both single crystal aluminum and recrystallized nickel.The results demonstrate the accuracy and stability of the new method compared to the conventional method.

  7. Parcels and Land Ownership, Published in 2011, Rutherford County Government.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Parcels and Land Ownership dataset as of 2011. The extent of these data is generally Rutherford County, TN. This metadata was auto-generated through the Ramona...

  8. On the Rutherford-Santilli neutron model

    Energy Technology Data Exchange (ETDEWEB)

    Burande, Chandrakant S. [Vilasrao Deshmukh College of Engineering and Technology, Mouda, India-441104, Email: csburande@gmail.com (India)

    2015-03-10

    In 1920 H. Rutherford conjectured that the first particle synthesized in stars is neutron from a proton and an electron after which all known matter is progressively synthesized. However, Pauli objected Rutherford’s version of neutron synthesis because inability to represent spin 1/2 of the neutron. Using this objection E. Fermi proposed emission of massless particle, called “neutrino”. However, Santilli has dismissed the neutrino hypothesis following certain ambiguities such as positive binding energy required in synthesis of neutron. He found that celebrated Schrödinger’s equation of quantum physics is not suitable for obtaining positive binding energy for bound state at the dimension of 10{sup −13}cm. In order to remove these shortcomings, Santilli has developed isomathematics and then hadronic mechanics, which allowed the time invariant representation of Hamiltonian and non-Hamiltonian interactions as needed for the neutron synthesis (see for example: References cited at [1]).Thus the anomalies pertaining to the binding energy, the spin and the magnetic moment got resolved. He successfully calculated missing positive binding energy via isonormalization of the mass for electron when totally immersed within the hyper-dense medium inside the proton. Considering Rutherford’s compression of the isoelectron within the proton in the singlet coupling, he also identified the spin 1/2 for neutron and calculated the magnetic moment of the neutron. In order to verify his logical concept, he repeated the Don Carlo Borghi experiment of synthesis of the neutron from proton and electrons and verified that the said setup indeed produces neutron-type particles called “neutroids” which latter is absorbed by the activated detector substances that produces known nuclear reactions. He dismissed the neutrino hypothesis and replaced it with a longitudinal impulse originating from the ether as a universal substratum, named, “etherino”. He pointed out that all the

  9. Traffic modifications on Routes Rutherford, Democrite and Fermi

    CERN Multimedia

    2015-01-01

    The GS Department would like to inform you that until the end of December, the construction of Building 245 will result in the following traffic modifications: Traffic on Route Rutherford will be partially restricted in front of the construction site, Traffic on Route Democrite will be one-way towards Route Rutherford. Also, please note that due to construction work in front of Building 377, Route Fermi will be closed from Wednesday, 10 June until Friday, 7 August. Thank you for your understanding.

  10. STUDY OF Ag DIFFUSION INTO Cu SINGLE CRYSTALS BY RUTHERFORD BACKSCATTERING SPECTROMETRY

    Institute of Scientific and Technical Information of China (English)

    R. Wang

    2003-01-01

    4. 0Me V 7 Li++ RBS was used for investigations of thermal diffusion of Ag in Cu single crystals. The annealing of samples was carried out in vacuum in the temperature range from 498K to 613K. The element depth concentration profiles transformed fiom RBS spectra indicate that the diffusion of Ag into Cu is a typical volume diffusion. The Arrhenius parameters corresponding to the diffusion were obtained.

  11. Backscattered electron imaging and windowless energy dispersive x-ray microanalysis: a new technique for gallstone analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kaufman, H.S.; Lillemoe, K.D.; Magnuson, T.H.; Frasca, P.; Pitt, H.A. (Johns Hopkins Univ. School of Medicine, Baltimore, MD (USA))

    1990-12-01

    Scanning electron microscopy with or without conventional energy dispersive x-ray microanalysis is currently used to identify gallstone microstructure and inorganic composition. Organic calcium salts are among many biliary constituents thought to have a role in gallstone nidation and growth. However, current analytical techniques which identify these salts are destructive and compromise gallstone microstructural data. We have developed a new technique for gallstone analysis which provides simultaneous structural and compositional identification of calcium salts within gallstones. Backscattered electron imaging is used to localize calcium within cholesterol at minimum concentrations of 0.01%. Windowless energy dispersive x-ray microanalysis produces elemental spectra of gallstone calcium salts which are qualitatively and quantitatively different. These combined techniques provide simultaneous structural and compositional information obtained from intact gallstone cross-sections and have been used to identify calcium salts in gallstones obtained at cholecystectomy from 106 patients.

  12. Comparison of ischemic side effects of levosimendan and dobutamine with integrated backscatter analysis.

    Science.gov (United States)

    Duygu, Hamza; Nalbantgil, Sanem; Zoghi, Mehdi; Ozerkan, Filiz; Yildiz, Ahmet; Akilli, Azem; Akin, Mustafa

    2009-04-01

    Levosimendan improves cardiac contractility without increasing oxygen consumption. However, its effects on ischemia were not supported with the utilization of a noninvasive parameter of myocardial characterization. The changes observed in integrated backscatter (IBS) may be reflective of change in myocardial ischemia. In this study, the effect of levosimendan on ischemia detected by IBS was evaluated in patients with ischemic heart failure (HF). Patients who had LVEF medications were similar in both groups. A significant reduction in CVIBS was detected in anteroseptal (7.6 +/- 1.4 dB versus 5.9 +/- 0.8 dB, p = 0.01), inferior wall (7.4 +/- 0.8 dB versus 6.7 +/- 1.5 dB, p = 0.03), and posterolateral wall (9.0 +/- 1.2 dB versus 8.2 +/- 0.6 dB, p = 0.04) after dobutamine administration, while no significant changes were observed in the levosimendan group in all walls. Unlike dobutamine, levosimendan may not induce myocardial ischemia as shown by CVIBS at commonly used dosages in the setting of decompensated HF without active ischemia.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-08-15

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

  14. Analysis and Assessment of Neutron Backscattering Technique for Landmine Detection%中子背散射探雷技术的分析与评估

    Institute of Scientific and Technical Information of China (English)

    曹琳; 储诚胜; 滕君锐; 胡广春; 熊宗华; 郝樊华; 雷家荣; 陈涵德

    2012-01-01

    The analysis of physics principles of neutron backscattering technique and Monte Carlo simulation were presented for assessment of landmine detection by neutron backscattering technique. The results are greatly valuable for future research and engineering.%本文分析了中子背散射探雷技术的原理,通过数值模拟对中子背散射探雷技术进行研究,并对该技术进行分析评估,为进一步开展中子背散射探雷技术的工程研究提供理论基础.

  15. Imaging and analysis of subsurface Cu interconnects by detecting backscattered electrons in the scanning electron microscope

    Science.gov (United States)

    Gignac, L. M.; Kawasaki, M.; Boettcher, S. H.; Wells, O. C.

    2005-06-01

    Cu -SiO2-SiNx interconnects that were located 0.65-2.7-μm below the surface of silicon-integrated circuits were imaged in a scanning electron microscope and a transmission electron microscope with a scanning attachment by detecting backscattered electrons (BSEs) with an incident electron-beam energy (Eo) in the range of 30-400keV. BSE images could be used to detect voids in subsurface Cu interconnects, even in regions covered with upper level Cu lines or vias. As Eo was increased from 30to400keV, structures could be seen as a result of atomic number (Z) contrast farther below the surface while structures closer to the surface had reduced Z contrast. The subsurface beam diameter was measured from BSE images as a function of Eo and depth below the surface. For all Eo, the subsurface beam diameter initially rapidly increased with SiO2 overlayer thickness but, for 150keV, a leveling off in the beam spread was seen for depths >1.7μm. Beam broadening affected whether the TaN /Ta liners that surrounded the Cu conductors could be seen at the edges of the lines; this contrast was observed only when the subsurface beam diameter was ⩽1.5× the liner thickness. The BSE information depth for imaging 0.2-μm-sized voids in subsurface Cu -SiO2-SiNx interconnect structures at 30 and 150keV was estimated to be 0.65 and 3μm, respectively.

  16. Determination of nitrogen content in thick TiN layers by proton backscattering

    Energy Technology Data Exchange (ETDEWEB)

    Havranek, V.; Hnatowicz, V.; Kvitek, J. (Nuclear Physics Inst., Czechoslovak Academy of Sciences, Rez (Czechoslovakia)); Musil, J.; Poulek, V. (Inst. of Physics, Czechoslovak Academy of Sciences, Prague (Czechoslovakia))

    1990-06-01

    Non-Rutherford proton backscattering has been employed for the determination of the nitrogen content in TiN layers of a thickness of several micrometres deposited on a steel backing. The required proton scattering cross section has been measured using standards comprising thin TiN films on a light substrate. The scattering cross section of 2 MeV protons of nitrogen for {theta}{sub lab}=160deg was found to be 5.7 times the Rutherford value. Nitrogen detection limits in thick TiN samples are discussed. (orig.).

  17. submitter Optimization of Nb$_{3}$Sn Rutherford Cables Geometry for the High Luminosity LHC

    CERN Document Server

    Fleiter, Jerome; Bonasia, Angelo; Bordini, Bernardo; Richter, David

    2017-01-01

    The quadrupole and dipole magnets for the LHC High Luminosity (HL-LHC) upgrade will be based on Nb3Sn Rutherford cables that operate at 1.9 K and experience magnetic fields of up to about 12 T. An important step in the design of these magnets is the development of the high aspect ratio Nb3Sn cables to achieve the nominal field with sufficient margin. The strong plastic deformation of unreacted $Nb_3Sn$ strands during the Rutherford cabling process may induce non negligible $I_c$ and RRR degradation. In this paper, the cabling degradation is investigated as a function of the cable geometry for both PIT and RRP conductors. Based on this analysis, new baseline geometries for both 11 T and QXF magnets of HL-LHC are proposed.

  18. Traffic modifications on Routes Rutherford, Democrite and Fermi

    CERN Multimedia

    2015-01-01

    The GS Department would like to inform you that, until the end of December, the construction of Building 245 will result in the following traffic modifications: Traffic on Route Rutherford will be partially restricted in front of the construction site, Traffic on Route Democrite will be one-way towards Route Rutherford. Also, please note that due to construction work in front of Building 377, Route Fermi will be closed from Wednesday, 10 June until Friday, 7 August. Thank you for your understanding.

  19. Structural analysis of multilayer metal nitride films CrN/MoN using electron backscatter diffraction (EBSD)

    Science.gov (United States)

    Postolnyi, Bogdan; Bondar, Oleksandr; Opielak, Marek; Rogalski, Przemysław; Araújo, João. Pedro

    2016-12-01

    The electron backscatter diffraction (EBSD) analysis method was used for studying structure and properties of multilayer nitride CrN/MoN coatings fabricated by cathode arc physical vapour deposition (Arc-PVD). Samples were deposited on steel substrate with different single layer thickness from tens nanometers to 1 micron and with total thickness of coatings up to 8-13 μm. Colour grains mapping, grain size distribution profiles, pole figures and texture analyses were the main research instruments. Studying of obtained coatings was performed on specially prepared polished cross-section samples. The dependence between single layer thickness and grain size of materials, which is also changing through depth profile of the coating, was observed. In addition, it was possible to study phase composition, prevailing crystals orientation, dominant texture and grains growth. Studying of grains size, as well as other indicated parameters, is a very important task because it gives an information about grains interfaces volume, which causes changes in mechanical properties of material. Obtained results were cross-checked by X-ray diffraction analysis (XRD) where it was possible.

  20. Ultrasonic backscatter from cancellous bone: the apparent backscatter transfer function.

    Science.gov (United States)

    Hoffmeister, Brent K; Mcpherson, Joseph A; Smathers, Morgan R; Spinolo, P Luke; Sellers, Mark E

    2015-12-01

    Ultrasonic backscatter techniques are being developed to detect changes in cancellous bone caused by osteoporosis. Many techniques are based on measurements of the apparent backscatter transfer function (ABTF), which represents the backscattered power from bone corrected for the frequency response of the measurement system. The ABTF is determined from a portion of the backscatter signal selected by an analysis gate of width τw delayed by an amount τd from the start of the signal. The goal of this study was to characterize the ABTF for a wide range of gate delays (1 μs ≤ τd ≤ 6 μs) and gate widths (1 μs ≤ τw ≤ 6 μs). Measurements were performed on 29 specimens of human cancellous bone in the frequency range 1.5 to 6.0 MHz using a broadband 5-MHz transducer. The ABTF was found to be an approximately linear function of frequency for most choices of τd and τw. Changes in τd and τw caused the frequency-averaged ABTF [quantified by apparent integrated backscatter (AIB)] and the frequency dependence of the ABTF [quantified by frequency slope of apparent backscatter (FSAB)] to change by as much as 24.6 dB and 6.7 dB/MHz, respectively. τd strongly influenced the measured values of AIB and FSAB and the correlation of AIB with bone density (-0.95 ≤ R ≤ +0.68). The correlation of FSAB with bone density was influenced less strongly by τd (-0.97 ≤ R ≤ -0.87). τw had a weaker influence than τd on the measured values of AIB and FSAB and the correlation of these parameters with bone density.

  1. Displacement analysis of diagnostic ultrasound backscatter: a methodology for characterizing, modeling, and monitoring high intensity focused ultrasound therapy.

    Science.gov (United States)

    Speyer, Gavriel; Kaczkowski, Peter J; Brayman, Andrew A; Crum, Lawrence A

    2010-07-01

    Accurate monitoring of high intensity focused ultrasound (HIFU) therapy is critical for widespread clinical use. Pulse-echo diagnostic ultrasound (DU) is known to exhibit temperature sensitivity through relative changes in time-of-flight between two sets of radio frequency (RF) backscatter measurements, one acquired before and one after therapy. These relative displacements, combined with knowledge of the exposure protocol, material properties, heat transfer, and measurement noise statistics, provide a natural framework for estimating the administered heating, and thereby therapy. The proposed method, termed displacement analysis, identifies the relative displacements using linearly independent displacement patterns, or modes, each induced by a particular time-varying heating applied during the exposure interval. These heating modes are themselves linearly independent. This relationship implies that a linear combination of displacement modes aligning the DU measurements is the response to an identical linear combination of heating modes, providing the heating estimate. Furthermore, the accuracy of coefficient estimates in this approximation is determined a priori, characterizing heating, thermal dose, and temperature estimates for any given protocol. Predicted performance is validated using simulations and experiments in alginate gel phantoms. Evidence for a spatially distributed interaction between temperature and time-of-flight changes is presented.

  2. Evaluation of ozone column amount from the solar backscattering spectra measured with the Airborne-OPUS and error analysis

    Science.gov (United States)

    Nakata, T.; Kita, K.; Suzuki, M.; Shiomi, K.; Okumura, S.; Ogawa, T.

    Satellite observation is one of the best methods to monitor the increase of atmospheric pollutants including tropospheric ozone especially due to industrial activities in Asia It is significant to investigate the satellite sensor and data processing algorithm for developing next generation monitoring system The Airborne Ozone and Pollution measuring Ultraviolet Spectrometer Airborne-OPUS sensor was developed by JAXA EORC to study the solar ultraviolet backscattering measurement of ozone nitrogen dioxide sulfur dioxide and some other species from a satellite In this study we deduced slant column amounts of ozone from the Airborne-OPUS data during an aircraft observation and estimated analytical errors The Airborne-OPUS which consists of a compact spectrometer Jobin-Yvon CP-200 thermoelectric-cooled CCD SpectraVideo SV11C and optics measures backward-scattered ultraviolet spectra between 300 and 455 nm with a spectral resolution of 0 9 nm FWHM from an aircraft In this study the spectra between 315 and 325 nm obtained during Pacific Exploration and Asia and Continental Emission phase-A campaign Parrish et al 2004 in January 2002 were analyzed to evaluate the ozone column amount In this analysis the absorption by ozone the scattering by atmospheric molecules and the Ring effect were estimated from the ratios between the target spectra derived when the solar zenith angle SZA exceeded about 60o and the reference spectra when SZA was minimum at the same day The scattering by aerosols surface albedo and artificial continuous

  3. Coupling currents in Rutherford cables under time varying conditions

    NARCIS (Netherlands)

    Verweij, A.P.; Kate, ten H.H.J.

    1993-01-01

    A network model is presented to simulate fully transposed Rutherford cables under time varying conditions. The intrinsic properties of the cable and the external applied conditions can be changed spatially. Several statistical distributions of the contact resistances are built in to investigate loca

  4. Experimenting from a Distance in the Case of Rutherford Scattering

    Science.gov (United States)

    Grober, S.; Vetter, M.; Eckert, B.; Jodl, H. -J.

    2010-01-01

    The Rutherford scattering experiment plays a central role in working out atomic models in physics and chemistry. Nevertheless, the experiment is rarely performed at school or in introductory physics courses at university. Therefore, we realized this experiment as a remotely controlled laboratory (RCL), i.e. the experiment is set up in reality and…

  5. Dark energy and the Rutherford-Soddy radiative decay law

    CERN Document Server

    Bento, M C

    2009-01-01

    It is argued that a putative evolution of the fundamental couplings of strong and weak interactions via coupling to dark energy through a generalized Bekenstein-type model may, for a linear model of variation, cause deviations on the statistical nuclear decay Rutherford-Soddy law unless bounds are imposed on the parameters of this variation.

  6. Ion Temperature-Measurements in Tokamak Plasmas by Rutherford Scattering

    NARCIS (Netherlands)

    Vanblokland, A. A. E.; Barbian, E. P.; Donne, A. J. H.; van der Grift, A. F.; Grimbergen, T. W. M.; Oyevaar, T.; Schüller, F. C.; Tammen, H. F.; Vanderven, H. W.; Vijverberg, T. F.; Dewinter, F. D. A.; Bertschinger, G.; Cosler, A.; Korten, M.

    1992-01-01

    A Rutherford scattering diagnostic has been applied at the TEXTOR tokamak to obtain spatially and temporally resolved information on the temperature of the bulk ions in the plasma. In the experimental setup, a helium atomic beam (30-keV, 12-mA equivalent current) passes vertically through the plasma

  7. Numerical Analysis of Ultrasound Backscattered Waves in Cancellous Bone Using a Finite-Difference Time-Domain Method: Isolation of the Backscattered Waves From Various Ranges of Bone Depths.

    Science.gov (United States)

    Hosokawa, Atsushi

    2015-06-01

    Using a finite-difference time-domain method, ultrasound backscattered waves inside cancellous bone were numerically analyzed to investigate the backscatter mechanism. Two bone models with different thicknesses were modeled with artificial absorbing layers positioned at the back surfaces of the model, and an ultrasound pulse wave was transmitted toward the front surface. By calculating the difference between the simulated waveforms obtained using the two bone models, the backscattered waves from a limited range of depths in cancellous bone could be isolated. The results showed that the fast and slow longitudinal waves, which have previously been observed only in the ultrasound waveform transmitted through the bone, could be distinguished in the backscattered waveform from a deeper bone depth when transmitting the ultrasound wave parallel to the main orientation of the trabecular network. The amplitudes of the fast and slow backscattered waves were more closely correlated with the bone porosity [R2 = 0.84 and 0.66 (p different times.

  8. High resolution backscattering studies of nanostructured magnetic and semiconducting materials

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, A. [Instituto Tecnologico e Nuclear, Dept. Fisica, Estrada Nac. 10, 2686-953 Sacavem (Portugal)]. E-mail: afonseca@itn.pt; Franco, N. [Instituto Tecnologico e Nuclear, Dept. Fisica, Estrada Nac. 10, 2686-953 Sacavem (Portugal); Alves, E. [Instituto Tecnologico e Nuclear, Dept. Fisica, Estrada Nac. 10, 2686-953 Sacavem (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Barradas, N.P. [Instituto Tecnologico e Nuclear, Dept. Fisica, Estrada Nac. 10, 2686-953 Sacavem (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal); Leitao, J.P. [Departamento de Fisica da Universidade de Aveiro, 3810-193 Aveiro (Portugal); Sobolev, N.A. [Departamento de Fisica da Universidade de Aveiro, 3810-193 Aveiro (Portugal); Banhart, D.F. [Z. E. Elektronenmikroskopie, Universitaet Ulm, Albert-Einstein-Allee 11, D-89069 Ulm (Germany); Presting, H. [Daimler-Chrysler Forschungszentrum, 89081 Ulm (Germany); Ulyanov, V.V. [Institute of Semiconductor Physics, 630090 Novosibirsk (Russian Federation); Nikiforov, A.I. [Institute of Semiconductor Physics, 630090 Novosibirsk (Russian Federation)

    2005-12-15

    Low dimension structures raises inevitably new technological challenges in materials science. The new structures must fulfill stringent requirements in composition, crystalline quality and interface sharpness among others. We present and discuss the results of Si/Ge quantum structures and FePt/C multilayer structures deposited at different temperatures by ion beam sputtering. Evidence for the presence of FePt nanoparticles embedded in the C matrix and Ge islands in Ge/Si multilayers structures was found. Size and stoichiometry of the nanoparticles and the multilayer periodicity was obtained using Rutherford backscattering at grazing angles of incidence. The strain state of the single crystalline layers was determined by tilt axis channelling.

  9. Blind breast tissue diagnosis using independent component analysis of localized backscattering response

    Science.gov (United States)

    Eguizabal, Alma; Laughney, Ashley M.; García Allende, Pilar Beatriz; Krishnaswamy, Venkataramanan; Wells, Wendy A.; Paulsen, Keith D.; Pogue, Brian W.; Lopez-Higuera, Jose M.; Conde, Olga M.

    2012-03-01

    A blind separation technique based on Independent Component Analysis (ICA) is proposed for breast tumor delineation and pathologic diagnosis. Tissue morphology is determined by fitting local measures of tissue reflectance to a Mie theory approximation, parameterizing the scattering power, scattering amplitude and average scattering irradiance. ICA is applied on the scattering parameters by spatial analysis using the Fast ICA method to extract more determinant features for an accurate diagnostic. Neither training, nor comparisons with reference parameters are required. Tissue diagnosis is provided directly following ICA application to the scattering parameter images. Surgically resected breast tissues were imaged and identified by a pathologist. Three different tissue pathologies were identified in 29 samples and classified as not-malignant, malignant and adipose. Scatter plot analysis of both ICA results and optical parameters where obtained. ICA subtle ameliorates those cases where optical parameter's scatter plots were not linearly separable. Furthermore, observing the mixing matrix of the ICA, it can be decided when the optical parameters themselves are diagnostically powerful. Moreover, contrast maps provided by ICA correlate with the pathologic diagnosis. The time response of the diagnostic strategy is therefore enhanced comparing with complex classifiers, enabling near real-time assessment of pathology during breast-conserving surgery.

  10. Dynamic coherent backscattering mirror

    Energy Technology Data Exchange (ETDEWEB)

    Zeylikovich, I.; Xu, M., E-mail: mxu@fairfield.edu [Physics Department, Fairfield University, Fairfield, CT 06824 (United States)

    2016-02-15

    The phase of multiply scattered light has recently attracted considerable interest. Coherent backscattering is a striking phenomenon of multiple scattered light in which the coherence of light survives multiple scattering in a random medium and is observable in the direction space as an enhancement of the intensity of backscattered light within a cone around the retroreflection direction. Reciprocity also leads to enhancement of backscattering light in the spatial space. The random medium behaves as a reciprocity mirror which robustly converts a diverging incident beam into a converging backscattering one focusing at a conjugate spot in space. Here we first analyze theoretically this coherent backscattering mirror (CBM) phenomenon and then demonstrate the capability of CBM compensating and correcting both static and dynamic phase distortions occurring along the optical path. CBM may offer novel approaches for high speed dynamic phase corrections in optical systems and find applications in sensing and navigation.

  11. Dynamic coherent backscattering mirror

    Science.gov (United States)

    Xu, M.

    2016-01-01

    The phase of multiply scattered light has recently attracted considerable interest. Coherent backscattering is a striking phenomenon of multiple scattered light in which the coherence of light survives multiple scattering in a random medium and is observable in the direction space as an enhancement of the intensity of backscattered light within a cone around the retroreflection direction. Reciprocity also leads to enhancement of backscattering light in the spatial space. The random medium behaves as a reciprocity mirror which robustly converts a diverging incident beam into a converging backscattering one focusing at a conjugate spot in space. Here we first analyze theoretically this coherent backscattering mirror (CBM) phenomenon and then demonstrate the capability of CBM compensating and correcting both static and dynamic phase distortions occurring along the optical path. CBM may offer novel approaches for high speed dynamic phase corrections in optical systems and find applications in sensing and navigation. PMID:26937296

  12. Alexander Cameron Rutherford: A Gentleman and a Scholar. Documents in the Classroom.

    Science.gov (United States)

    Hodysh, Henry W.

    2000-01-01

    Provides information about Alexander Cameron Rutherford, a provincial politician. Includes a letter written by Rutherford in 1912 that provides insights into his responsibilities to the general public, information about Rutherford himself, the economic conditions of Alberta, Canada in 1912, and information about the individual to whom it was…

  13. Clinical characteristics of patients with Rutherford category IV, compared with V and VI

    Directory of Open Access Journals (Sweden)

    Taketsugu Tsuchiya

    2015-07-01

    Full Text Available Objective: Patients categorized Rutherford category IV might have different characteristics compared with Rutherford category V and VI. Our study aims were to estimate the clinical differences between Rutherford category IV and Rutherford category V and VI, for those underwent endovascular therapy for isolated infrapopliteal disease, and also to find risk factors for endovascular therapy in Rutherford category IV. Methods: Based on the Japanese multi-center registry data, 1091 patients with 1332 limbs (Rutherford category IV: 226 patients with 315 limbs, Rutherford category V and VI: 865 patients with 1017 limbs were analyzed retrospectively. Results: Patients’ backgrounds and lesions’ characteristics had significant differences. Both freedom rate from major adverse limb event with perioperative death and amputation-free survival rate at 1 year were better in Rutherford category IV than Rutherford category V and VI (93.6% vs 78.3%, 87.7% vs 66.7% and those maintained to 3 years (p  3.0 mg/dL, chronic obstructive pulmonary disease, and coronary artery disease in Rutherford category IV. Conclusion: From the present results, Rutherford category IV should be recognized to have quite different backgrounds and better outcome from Rutherford category V and VI.

  14. Analysis of snowpack properties and structure from TerraSAR-X data, based on multilayer backscattering and snow evolution modeling approaches

    CERN Document Server

    Phan, Xuan-Vu; Gay, Michel; Durand, Yves; Dumont, Marie; Allain, Sophie; D'Urso, Guy

    2012-01-01

    Recently launched high precision Synthetic Aperture Radar (SAR) satellites such as TerraSAR-X, COSMO-SkyMed, etc. present a high potential for better observation and characterization of the cryosphere. This study introduces a new approach using high frequency (X-band) SAR data and an Electromagnetic Backscattering Model (EBM) to constrain the detailed snowpack model Crocus. A snowpack EBM based on radiative transfer theory, previously used for C-band applications, is adapted for the X-band. From measured or simulated snowpack stratigraphic profiles consisting of snow optical grain radius and density, this forward model calculates the backscattering coefficient for different polarimetric channels. The output result is then compared with spaceborne TerraSAR-X acquisitions to evaluate the forward model. Next, from the EBM, the adjoint operator is developed and used in a variational analysis scheme in order to minimize the discrepancies between simulations and SAR observations. A time series of TerraSAR-X acquisi...

  15. Back-scatter analysis based algorithms for increasing transmission through highly-scattering random media using phase-only modulated wavefronts

    CERN Document Server

    Jin, Curtis; Michielssen, Eric; Rand, Stephen

    2014-01-01

    Recent theoretical and experimental advances have shed light on the existence of so-called `perfectly transmitting' wavefronts with transmission coefficients close to 1 in strongly backscattering random media. These perfectly transmitting eigen-wavefronts can be synthesized by spatial amplitude and phase modulation. Here, we consider the problem of transmission enhancement using phase-only modulated wavefronts. We develop physically realizable iterative and non-iterative algorithms for increasing the transmission through such random media using backscatter analysis. We theoretically show that, despite the phase-only modulation constraint, the non-iterative algorithms will achieve at least about 25$\\pi$% or about 78.5% transmission assuming there is at least one perfectly transmitting eigen-wavefront and that the singular vectors of the transmission matrix obey a maximum entropy principle so that they are isotropically random. We numerically analyze the limits of phase-only modulated transmission in 2-D with f...

  16. Energy-dispersive spectroscopy and electron backscatter diffraction analysis of isothermally aged SAF 2507 type superduplex stainless steel

    Science.gov (United States)

    Dobranszky, J.; Szabo, P. J.; Berecz, T.; Hrotko, V.; Portko, M.

    2004-10-01

    Due to thermal effects, several precipitation and segregation processes are known in duplex stainless steels. These microstructural changes influence both of the original phases, but in different ways. Isothermal ageing in a large range of temperature was performed on SAF 2507 type steel. The temperature range was 300-1000 °C, the ageing time was between 100 s and 24 h. This paper discusses the results of ageing at 900 °C. Microstructural changes were investigated by electron microscopy, energy-dispersive spectroscopy and electron backscattered diffraction analysis. This technique allowed the determination of the microstructure of the secondary austenite and sigma phase and their mutual orientation properties. Beside this, thermoelectric power measurements were also performed, which gave information about the kinetics of the precipitation process. Results showed that sigma-phase precipitation started right after 200 s in the case of annealed steel, and faster than 100 s in the cold-rolled state. After 5000 s, the delta-ferrite disappeared. Chemical composition of sigma phase was independent on the ageing time. A small decrease in nickel content was observed with a slight increase of Cr content. Small amount of chi phase had also been observed on the ferrite-ferrite boundaries, but later they changed into sigma phase. Similarly to sigma phase, chi phase showed significant phosphorus enrichment. During ageing, small chrome nitride precipitates developed, which amount increased in time, and some vanadium could be measured in them. The orientation relationship between austenite and sigma phase deviated from Nenno-orientationship with about 24°, and seems to form a [110]‖[310] relationship, which was characteristic right from the beginning of the process, and remains more or less constant.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-01

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

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

    Science.gov (United States)

    Choudhury, Soud Farhan; Ladani, Leila

    2014-04-01

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

  19. Science & Society: The search for the real Earnest Rutherford*

    CERN Multimedia

    2003-01-01

    Every physicist knows the name Rutherford who radically altered our understanding of nature on three separate occasions. Through brilliantly conceived experiments, and with special insight, he explained the perplexing problem of radioactivity as the spontaneous disintegration of atoms (they were not necessarily stable entities as had been assumed since the time of the ancient Greeks), he determined the structure of the atom and he was the world's first successful alchemist (he converted nitrogen into oxygen). This talk given by John Campbell, however, will cover some of the lesser known aspects of Rutherford's work, including his early wireless signalling, development of what was later improved to be now called the Geiger-Muller tube, his acoustic work for submarine detection during the First World War, the development of particle accelerators and the race to use them, the first use of a coincidence detector, and why he received just one Nobel Prize. Dr Campbell, a condensed matter physicist at the Universi...

  20. Design, processing, and properties of Bi 2212\\/Ag Rutherford cables

    CERN Document Server

    Collings, E W; Scanlan, R M; Dietderich, D R; Motowidlo, L R; Sokolowski, R S; Aoki, Y; Hasegawa, T

    1999-01-01

    In a program intended to explore the use of high temperature superconducting (HTSC) cables in high field synchrotron dipole magnets model Bi:2212/Ag Rutherford cables were designed bearing in mind the needs for mechanical integrity, relatively high tensile strength, and low coupling losses. To satisfy these needs a core-type cable design was selected and a readily available heat-resistant core material acquired. Cables were wound for critical current- and AC loss measurement. Both winding-induced (mechanical) and core-induced (chemical) critical current degradation was examined. Interstrand coupling loss was measured calorimetrically on model cable samples with bare- and oxide-coated cores. From the results it was predicted that the losses of full-scale Bi:2212/Ag-wound LHC-type Rutherford cables would fall close to the acceptability range for the windings of high-field accelerator dipoles. (10 refs).

  1. New Measurements and Quantitative Analysis of Electron Backscattering in the Energy Range of Neutron Beta-Decay

    CERN Document Server

    Martin, J W; Filippone, B W; Hoedl, S A; Ito, T M; Plaster, B; Young, A R; Yuan, J

    2006-01-01

    We report on the first detailed measurements of electron backscattering from plastic scintillator targets, extending our previous work on beryllium and silicon targets. The scintillator experiment posed several additional experimental challenges associated with charging of the scintillator target, and those challenges are addressed in detail. In addition, we quantitatively compare the energy and angular distributions of this data, and our previous data, with electron transport simulations based on the Geant4 and Penelope Monte Carlo simulation codes. The Penelope simulation is found globally to give a superior description of the data. Such information is crucial for a broad array of weak-interaction physics experiments, where electron backscattering can give rise to the dominant detector-related systematic uncertainty.

  2. Displacement analysis of diagnostic ultrasound backscatter: A methodology for characterizing, modeling, and monitoring high intensity focused ultrasound therapy

    OpenAIRE

    2010-01-01

    Accurate monitoring of high intensity focused ultrasound (HIFU) therapy is critical for widespread clinical use. Pulse-echo diagnostic ultrasound (DU) is known to exhibit temperature sensitivity through relative changes in time-of-flight between two sets of radio frequency (RF) backscatter measurements, one acquired before and one after therapy. These relative displacements, combined with knowledge of the exposure protocol, material properties, heat transfer, and measurement noise statistics,...

  3. Ion beam analysis fundamentals and applications

    CERN Document Server

    Nastasi, Michael; Wang, Yongqiang

    2015-01-01

    Ion Beam Analysis: Fundamentals and Applications explains the basic characteristics of ion beams as applied to the analysis of materials, as well as ion beam analysis (IBA) of art/archaeological objects. It focuses on the fundamentals and applications of ion beam methods of materials characterization.The book explains how ions interact with solids and describes what information can be gained. It starts by covering the fundamentals of ion beam analysis, including kinematics, ion stopping, Rutherford backscattering, channeling, elastic recoil detection, particle induced x-ray emission, and nucle

  4. Experimenting from a distance in the case of Rutherford scattering

    Science.gov (United States)

    Gröber, S.; Vetter, M.; Eckert, B.; Jodl, H.-J.

    2010-07-01

    The Rutherford scattering experiment plays a central role in working out atomic models in physics and chemistry. Nevertheless, the experiment is rarely performed at school or in introductory physics courses at university. Therefore, we realized this experiment as a remotely controlled laboratory (RCL), i.e. the experiment is set up in reality and can be operated by a computer via the Internet. We present results of measurements and supplementary didactical material. In addition, we make suggestions on how to use the RCL in class and we describe the added value of performing this experiment as an RCL.

  5. Strand critical current degradation in $Nb_{3}$ Sn Rutherford cables

    CERN Document Server

    Barzi, E; Higley, H C; Scanlan, R M; Yamada, R; Zlobin, A V

    2001-01-01

    Fermilab is developing 11 Tesla superconducting accelerator magnets based on Nb/sub 3/Sn superconductor. Multifilamentary Nb/sub 3/Sn strands produced using the modified jelly roll, internal tin, and powder-in-tube technologies were used for the development and test of the prototype cable. To optimize the cable geometry with respect to the critical current, short samples of Rutherford cable with packing factors in the 85 to 95% range were fabricated and studied. In this paper, the results of measurements of critical current, n-value and RRR made on the round virgin strands and on the strands extracted from the cable samples are presented. (5 refs).

  6. Calculation of minimum quench energies in Rutherford cables

    CERN Document Server

    Wilson, M N

    1996-01-01

    The Minimum Quench Energy MQE of a conductor may give some indication about the likelihood of training in magnets. We have used a numerical solution of the heat flow equation to calculate the MQE of a single superconducting wire and have found the results to be in good agreement with experiment. This model was then extended to an approximate representation of Rutherford cable by including current and heat transfer between strands. Reasonable agreement with experiment has been found, although in some cases it appears that the effective thermal contact between strands is greater than expected from electrical resistance measurements.

  7. The collected papers of Lord Rutherford of Nelson

    CERN Document Server

    Rutherford, Ernest

    2014-01-01

    This is the third of three volumes which together contain the complete range of Lord Rutherford's scientific papers, incorporating in addition addresses, general lectures, letters to editors, accounts of his scientific work and personal recollections by friends and colleagues. The final volume, first published in 1965, covers his period as Cavendish Professor from 1919 to 1937. Following on the immense fertility of his years in Manchester - only overshadowed towards the end by the war - we now turn to his last years as a world figure at the Cavendish Laboratory, where he continued his work on

  8. The collected papers of Lord Rutherford of Nelson

    CERN Document Server

    Rutherford, Ernest

    1962-01-01

    This is the third of three volumes which together contain the complete range of Lord Rutherford's scientific papers, incorporating in addition addresses, general lectures, letters to editors, accounts of his scientific work and personal recollections by friends and colleagues. The final volume, first published in 1965, covers his period as Cavendish Professor from 1919 to 1937. Following on the immense fertility of his years in Manchester - only overshadowed towards the end by the war - we now turn to his last years as a world figure at the Cavendish Laboratory, where he continued his work on

  9. Analysis of the Dielectric constant of saline-alkali soils and the effect on radar backscattering coefficient: a case study of soda alkaline saline soils in Western Jilin Province using RADARSAT-2 data.

    Science.gov (United States)

    Li, Yang-yang; Zhao, Kai; Ren, Jian-hua; Ding, Yan-ling; Wu, Li-li

    2014-01-01

    Soil salinity is a global problem, especially in developing countries, which affects the environment and productivity of agriculture areas. Salt has a significant effect on the complex dielectric constant of wet soil. However, there is no suitable model to describe the variation in the backscattering coefficient due to changes in soil salinity content. The purpose of this paper is to use backscattering models to understand behaviors of the backscattering coefficient in saline soils based on the analysis of its dielectric constant. The effects of moisture and salinity on the dielectric constant by combined Dobson mixing model and seawater dielectric constant model are analyzed, and the backscattering coefficient is then simulated using the AIEM. Simultaneously, laboratory measurements were performed on ground samples. The frequency effect of the laboratory results was not the same as the simulated results. The frequency dependence of the ionic conductivity of an electrolyte solution is influenced by the ion's components. Finally, the simulated backscattering coefficients measured from the dielectric constant with the AIEM were analyzed using the extracted backscattering coefficient from the RADARSAT-2 image. The results show that RADARSAT-2 is potentially able to measure soil salinity; however, the mixed pixel problem needs to be more thoroughly considered.

  10. Spectral variability of the particulate backscattering ratio

    Science.gov (United States)

    Whitmire, A. L.; Boss, E.; Cowles, T. J.; Pegau, W. S.

    2007-05-01

    The spectral dependency of the particulate backscattering ratio is relevant in the fields of ocean color inversion, light field modeling, and inferring particle properties from optical measurements. Aside from theoretical predictions for spherical, homogeneous particles, we have very limited knowledge of the actual in situ spectral variability of the particulate backscattering ratio. This work presents results from five research cruises that were conducted over a three-year period. Water column profiles of physical and optical properties were conducted across diverse aquatic environments that offered a wide range of particle populations. The main objective of this research was to examine the behavior of the spectral particulate backscattering ratio in situ, both in terms of its absolute magnitude and its variability across visible wavelengths, using over nine thousand 1-meter binned data points for each of five wavelengths of the spectral particulate backscattering ratio. Our analysis reveals no spectral dependence of the particulate backscattering ratio within our measurement certainty, and a geometric mean value of 0.013 for this dataset. This is lower than the commonly used value of 0.0183 from Petzold’s integrated volume scattering data. Within the first optical depth of the water column, the mean particulate backscattering ratio was 0.010.

  11. GLOBE backscatter - Climatologies and mission results. [Global Backscatter Experiment

    Science.gov (United States)

    Menzies, Robert T.; Post, Madison J.

    1991-01-01

    The Global Backscatter Experiment (GLOBE) goals require intensive study of the global climatology of atmospheric aerosol backscatter at IR wavelengths. Airborne and ground-based lidars have been developed to measure atmospheric backscatter profiles at CO2 laser wavelengths. Descriptions of the calibration techniques and selected measurement results are presented.

  12. Comparison of carotid plaque tissue characteristics in patients with acute coronary syndrome or stable angina pectoris: assessment by iPlaque, transcutaneous carotid ultrasonography with integrated backscatter analysis.

    Science.gov (United States)

    Bando, Mika; Yamada, Hirotsugu; Kusunose, Kenya; Fukuda, Daiju; Amano, Rie; Tamai, Rina; Torii, Yuta; Hirata, Yukina; Nishio, Susumu; Yamaguchi, Koji; Soeki, Takeshi; Wakatsuki, Tetsuzo; Sata, Masataka

    2015-07-25

    The association of the tissue characteristics of carotid plaques with coronary artery disease has attracted interest. The present study compared the tissue characteristics of carotid plaques in patients with acute coronary syndrome (ACS) with those in patients with stable angina pectoris (SAP) using the iPlaque system, which is based on ultrasound integrated backscatter. Carotid ultrasound examinations were performed in 26 patients with ACS, and 38 age- and gender-matched patients with SAP. Neither plaque area nor maximal intima-media thickness differed significantly between the two groups. However, the average integrated backscatter value within the plaque was greater in the ACS patients than in the SAP patients. iPlaque analysis revealed that the percentage blue area (lipid pool) was greater in the ACS patients than in the SAP patients (43.4 ± 11.2 vs 18.3 ± 10.3%, p < 0.0001), and that the percentage green area (fibrosis) was lower in the ACS than in the SAP patients (7.5 ± 7.5% vs 20.7 ± 11.7%, p < 0.0001). The lipid component of carotid plaques is greater in ACS patients than in SAP patients. Our iPlaque system provides a useful and feasible method for the tissue characterization of carotid plaques in the clinical setting.

  13. Backscatter Analysis Using Multi-Temporal and Multi-Frequency SAR Data in the Context of Flood Mapping at River Saale, Germany

    Directory of Open Access Journals (Sweden)

    Sandro Martinis

    2015-06-01

    Full Text Available In this study, an analysis of multi-temporal and multi-frequency Synthetic Aperture Radar data is performed to investigate the backscatter behavior of various semantic classes in the context of flood mapping in central Europe. The focus is mainly on partially submerged vegetation such as forests and agricultural fields. The test area is located at River Saale, Saxony-Anhalt, Germany, which is covered by a time series of 39 TerraSAR-X data acquired within the time interval December 2009 to June 2013. The data set is supplemented by ALOS PALSAR L-band and RADARSAT-2 C-band data. The time series covers two inundations in January 2011 and June 2013 which allows evaluating backscatter variations between flood periods and normal water level conditions using different radar wavelengths. According to the results, there is potential in detecting flooding beneath vegetation in all microwave wavelengths, even in X-band for sparse vegetation or leaf-off forests.

  14. Iterative, backscatter-analysis algorithms for increasing transmission and focusing light through highly-scattering random media

    CERN Document Server

    Jin, Curtis; Michielssen, Eric; Rand, Stephen

    2013-01-01

    Scattering hinders the passage of light through random media and consequently limits the usefulness of optical techniques for sensing and imaging. Thus, methods for increasing the transmission of light through such random media are of interest. Against this backdrop, Dorokhov, Pendry and others theoretically predicted the existence of a few highly transmitting eigen-wavefronts with transmission coefficients close to one in strongly backscattering random media. The breakthrough experiments of Vellekoop and Mosk confirmed the existence of these highly transmitting eigen-wavefronts and demonstrated that they could be discovered by using information from the far side of the scattering medium. Here, we numerically analyze this phenomenon in 2-D with fully spectrally accurate simulators and provide rigorous numerical evidence confirming the existence of these highly transmitting eigen-wavefronts in random media composed of hundreds of thousands of non-absorbing scatterers. We then develop physically realizable algo...

  15. THERMAL NEUTRON BACKSCATTER IMAGING.

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-10-16

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

  16. Towards a more comprehensive microstructural analysis of Zr-2.5Nb pressure tubing using image analysis and electron backscattered diffraction (EBSD)

    Energy Technology Data Exchange (ETDEWEB)

    Hovington, P., E-mail: hovington.pierre@ireq.c [Materials Science, Institut de recherche d' Hydro-Quebec, 1800 Lionel-Boulet, Varennes, Quebec, J3X 1S1 (Canada); Pinard, P.T. [Mining and Materials Engineering Department, McGill University, 3610 University St., Montreal, Quebec, H3A 2B2 (Canada); Lagace, M.; Rodrigue, L. [Materials Science, Institut de recherche d' Hydro-Quebec, 1800 Lionel-Boulet, Varennes, Quebec, J3X 1S1 (Canada); Gauvin, R. [Mining and Materials Engineering Department, McGill University, 3610 University St., Montreal, Quebec, H3A 2B2 (Canada); Trudeau, M.L. [Materials Science, Institut de recherche d' Hydro-Quebec, 1800 Lionel-Boulet, Varennes, Quebec, J3X 1S1 (Canada)

    2009-08-15

    Zr-2.5Nb pressure tubes used in CANDU (CANada Deuterium Uranium) reactors have a very complex microstructure, with two major crystallographic phases, {alpha} and {beta}. These phases include a fair amount of deformation from the extrusion process and the cold working ({approx}25%) performed at the end of the manufacturing process. This microstructure (texture, grain aspect ratio, etc.) changes along the tube's length and differs from tube to tube. In order to better understand the deformation mechanisms, these microstructural differences must be statistically characterized. Scanning electron microscopy combined with direct image analysis or with electron backscattered diffraction (EBSD) are good techniques for carrying out such a measurement. However it is not possible, using specimen preparation methods specific for each of these techniques, to reveal all of the grain and phase boundaries. We have thus developed post-treatment algorithms to be able to partially analyze the revealed Zr-2.5Nb microstructure. The first algorithm was used for image analysis treatments of micrographs taken at 5 kV on the radial-tangential plane of etched samples using a reactive ion etch (RIE, CF{sub 4} + O{sub 2}). The second was developed for EBSD grain mapping and can be used to characterize {alpha}-Zr grain shape and orientation. The two techniques are complementary: EBSD gives information about the micro-texture and the relationship between the microstructure and micro-texture while image analyses of SEM micrographs reveal the direction and distribution of the {alpha}-Zr lamellae more easily and over a greater sample area than EBSD. However, the SEM micrographs that were used did not reveal any grain boundary (only phase boundary). An analysis of EBSD grain maps reveals that the average {alpha}-Zr grain size, mainly in the elongated direction (tangential), is smaller than what is normally obtained from an image analysis of SEM micrographs. The grain size distribution of type

  17. Ion beam analysis of metal ion implanted surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Evans, P.J.; Chu, J.W.; Johnson, E.P.; Noorman, J.T. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Sood, D.K. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1993-12-31

    Ion implantation is an established method for altering the surface properties of many materials. While a variety of analytical techniques are available for the characterisation of implanted surfaces, those based on particle accelerators such as Rutherford backscattering (RBS) and nuclear reaction analysis (NRA) provide some of the most useful and powerful for this purpose. Application of the latter techniques to metal ion implantation research at ANSTO will be described with particular reference to specific examples from recent studies. Where possible, the information obtained from ion beam analysis will be compared with that derived from other techniques such as Energy Dispersive X-ray (EDX) and Auger spectroscopies. 4 refs., 5 figs.

  18. Simultaneous quantification of light elements in thin films deposited on Si substrates using proton EBS (Elastic Backscattering Spectroscopy)

    Science.gov (United States)

    Ferrer, F. J.; Alcaire, M.; Caballero-Hernández, J.; Garcia-Garcia, F. J.; Gil-Rostra, J.; Terriza, A.; Godinho, V.; García-López, J.; Barranco, A.; Fernández-Camacho, A.

    2014-08-01

    Quantification of light elements content in thin films is an important and difficult issue in many technological fields such as polymeric functional thin films, organic thin film devices, biomaterials, and doped semiconducting structures. Light elements are difficult to detect with techniques based on X-ray emission, such as energy dispersive analysis of X-rays (EDAX). Other techniques, like X-ray photoelectron spectroscopy (XPS), can easily quantify the content of light elements within a surface but often these surface measurements are not representative of the lights elements global composition of the thin film. Standard Rutherford backscattering spectroscopy (RBS), using alpha particles as probe projectiles, is not a good option to measure light elements deposited on heavier substrates composed of heavier elements like Si or glass. Nuclear Reaction Analysis (NRA) offers a good quantification method, but most of the nuclear reactions used are selective for the quantification of only one element, so several reactions and analysis are necessary to measure different elements. In this study, Elastic Backscattering Spectroscopy (EBS) using proton beams of 2.0 MeV simultaneously quantified different light elements (helium, carbon, nitrogen, oxygen, and fluorine) contained in thin films supported on silicon substrates. The capabilities of the proposed quantification method are illustrated with examples of the analysis for a series of thin film samples: amorphous silicon with helium bubbles, fluorinated silica, fluorinated diamond-like carbon and organic thin films. It is shown that this simple and versatile procedure allows the simultaneous quantification of light elements in thin films with thicknesses in the 200-500 nm range and contents lower than 10 at.%.

  19. 77 FR 61653 - Notice of Intent To Rule on Request To Release Airport Property at the Smyrna-Rutherford County...

    Science.gov (United States)

    2012-10-10

    ... Smyrna-Rutherford County Airport, Smyrna, TN AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... the release of land at the Smyrna-Rutherford County Airport, Smyrna, Tennessee. This property... review at the Smyrna--Rutherford County Airport, 278 Doug Warpoole Road, Smyrna, Tennessee 37167 and...

  20. Development of scaling rules for Rutherford type superconducting cables

    Energy Technology Data Exchange (ETDEWEB)

    Royet, J.M.; Scanlan, R.M.

    1990-09-01

    During the R D phase of the Superconducting Supercollider (SSC) program, LBL was responsible for establishing the parameters for cables used in SSC dipole and quadrupole magnets. In addition, the design and fabrication of a new cable for use in the Low Beta Quadrupoles. As a result of the development work on these and other cables, we have arrived a set of scaling rules which provide guidelines for choosing the parameters for a wide range of superconducting cables. These parameters include strand size, strand number, keystone angle, percent compaction, cable pitch and compacted cable dimensions. In addition, we have defined the tolerance ranges for the key cable manufacturing parameters such as mandrel size and shape, stand tension, and Turkshead temperature control. In this paper, we present the results on cables ranging from 8 strands to 36 strands of 0.65mm wire and from 8 strands to 30 strands of 0.8mm wire. We use these results to demonstrate the application of the scaling rules for Rutherford-type cable.

  1. SAR backscatter from coniferous forest gaps

    Science.gov (United States)

    Day, John L.; Davis, Frank W.

    1992-01-01

    A study is in progress comparing Airborne Synthetic Aperture Radar (AIRSAR) backscatter from coniferous forest plots containing gaps to backscatter from adjacent gap-free plots. Issues discussed are how do gaps in the range of 400 to 1600 sq m (approximately 4-14 pixels at intermediate incidence angles) affect forest backscatter statistics and what incidence angles, wavelengths, and polarizations are most sensitive to forest gaps. In order to visualize the slant-range imaging of forest and gaps, a simple conceptual model is used. This strictly qualitative model has led us to hypothesize that forest radar returns at short wavelengths (eg., C-band) and large incidence angles (e.g., 50 deg) should be most affected by the presence of gaps, whereas returns at long wavelengths and small angles should be least affected. Preliminary analysis of 1989 AIRSAR data from forest near Mt. Shasta supports the hypothesis. Current forest backscatter models such as MIMICS and Santa Barbara Discontinuous Canopy Backscatter Model have in several cases correctly predicted backscatter from forest stands based on inputs of measured or estimated forest parameters. These models do not, however, predict within-stand SAR scene texture, or 'intrinsic scene variability' as Ulaby et al. has referred to it. For instance, the Santa Barbara model, which may be the most spatially coupled of the existing models, is not truly spatial. Tree locations within a simulated pixel are distributed according to a Poisson process, as they are in many natural forests, but tree size is unrelated to location, which is not the case in nature. Furthermore, since pixels of a simulated stand are generated independently in the Santa Barbara model, spatial processes larger than one pixel are not modeled. Using a different approach, Oliver modeled scene texture based on an hypothetical forest geometry. His simulated scenes do not agree well with SAR data, perhaps due to the simple geometric model used. Insofar as texture

  2. Highly resolving Rutherford-scattering spectrometry for the study of ZrO{sub 2} layer growth in the beginning stage; Hochaufloesende Rutherford-Streuspektrometrie zur Untersuchung von ZrO{sub 2}-Schichtwachstum im Anfangsstadium

    Energy Technology Data Exchange (ETDEWEB)

    Vieluf, Maik

    2010-06-15

    By means of High Resolution Rutherford Backscattering Spectrometry (HR-RBS) the diffusion behaviour and layer growth of ZrO{sub 2} on SiO{sub 2} and TiN in the initial regime were investigated. The analysis of concentration profiles in ultrathin layers and interfaces was the focus of this work, made possible by the excellent depth resolution of less than 0.3 nm near the surface. For the first time a two-dimensional position sensitive semiconductor detector was implemented and characterized in the setup of the HR-RBS for the improvement of the quality of the measurement results. Furthermore, a measurement procedure was put into operation that allowed the reduction of ion induced damage. Through the optimization of the experimental conditions and the development of a program package for the support of the analyst, an efficient measurement procedure could be routinely ensured. At the time of a binary collision between the incident ion and the target element with a small impact factor, the charge state changes frequently, especially due to the abruptly decreasing ion velocity of the projectile and the overlapping of the electron clouds. For HR-RBS with an energy-separating dipole magnet, the charge state distribution of the scattered ions must be known for the interpretation of the measured spectra. For the first time a significant dependence of the charge state distribution of the scattered C ions on the layer thickness as well as atomic number of the detected target elements, here from the fourth subgroup, was demonstrated. This new knowledge allowed systematic investigations of the ZrO{sub 2} layer growth in the initial regime. The ZrO{sub 2} layers were produced by means of the atomic layer deposition (ALD). Based on the evidence for agglomeration of ZrO{sub 2} on SiO{sub 2} a method was introduced, which takes local thickness variations into account during the simulation of the HR-RBS spectra. An accurate statement about the ZrO{sub 2}/SiO{sub 2} interface was

  3. CHANGES OF BACKSCATTERING PARAMETERS DURING CHILLING INJURY IN BANANAS

    Directory of Open Access Journals (Sweden)

    NORHASHILA HASHIM

    2014-06-01

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

  4. Napa River Restoration Project: Rutherford Reach Completion and Oakville to Oak Knoll Reach

    Science.gov (United States)

    Information about the SFBWQP Napa River Restoration Project: Rutherford Reach Completion/Oakville to Oak Knoll, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  5. Rutherford's Enlarged: A Content-Embedded Activity To Teach about Nature of Science.

    Science.gov (United States)

    Abd-El-Khalick, Fouad

    2002-01-01

    Describes an activity that can be used to help middle and secondary school students develop more informed understandings of some important aspects of the nature of science in the context of teaching Rutherford's experiments and atomic structure. (Author/MM)

  6. Corneal Backscatter Analysis by In Vivo Confocal Microscopy: Fellow Eye Comparison of Small Incision Lenticule Extraction and Femtosecond Laser-Assisted LASIK

    Directory of Open Access Journals (Sweden)

    Alper Agca

    2014-01-01

    Full Text Available Purpose. To evaluate and compare corneal backscatter from anterior stroma between small incision lenticule extraction (SMILE and femtosecond laser-assisted LASIK (femto-LASIK. Methods. A cohort of 60 eyes of 30 patients was randomized to receive SMILE in one eye and femto-LASIK in the fellow eye. In vivo confocal microscopy was performed at 1 week and 1, 3, and 6 months after surgery. The main outcome measurements were maximum backscattered intensity and the depth from which it was measured, the backscattered light intensity 30 μm below Bowman’s membrane at the flap interface and 150 μm below the superficial epithelium, and the number of refractive particles at the flap interface. Results. The mean backscattered light intensity (LI at all measured depths and the maximum backscattered LI were higher in the SMILE group than the femto-LASIK group at all postoperative visits. LI differences at 1 week and 1- and 3-month visits were statistically significant (P<0,05. LI differences at 6 months were not statistically significant. There was no difference in the number of refractive particles at the flap interface between the groups at any visit. Conclusions. SMILE results in increased backscattered LI in the anterior stroma when compared with femto-LASIK were evaluated.

  7. Backscatter imagery in Jobos Bay

    Data.gov (United States)

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

  8. Collective stimulated Brillouin backscatter

    CERN Document Server

    Lushnikov, Pavel M

    2007-01-01

    We develop the statistical theory of the stimulated Brillouin backscatter (BSBS) instability of a spatially and temporally partially incoherent laser beam for laser fusion relevant plasma. We find a new regime of BSBS which has a much larger threshold than the classical threshold of a coherent beam in long-scale-length laser fusion plasma. Instability is collective because it does not depend on the dynamics of isolated speckles of laser intensity, but rather depends on averaged beam intensity. We identify convective and absolute instability regimes. Well above the incoherent threshold the coherent instability growth rate is recovered. The threshold of convective instability is inside the typical parameter region of National Ignition Facility (NIF) designs although current NIF bandwidth is not large enough to insure dominance of collective instability and suggests lower instability threshold due to speckle contribution. In contrast, we estimate that the bandwidth of KrF-laser-based fusion systems would be larg...

  9. Computer simulation of backscattering spectra from paint

    Science.gov (United States)

    Mayer, M.; Silva, T. F.

    2017-09-01

    To study the role of lateral non-homogeneity on backscattering analysis of paintings, a simplified model of paint consisting of randomly distributed spherical pigment particles embedded in oil/binder has been developed. Backscattering spectra for lead white pigment particles in linseed oil have been calculated for 3 MeV H+ at a scattering angle of 165° for pigment volume concentrations ranging from 30 vol.% to 70 vol.% using the program STRUCTNRA. For identical pigment volume concentrations the heights and shapes of the backscattering spectra depend on the diameter of the pigment particles: This is a structural ambiguity for identical mean atomic concentrations but different lateral arrangement of materials. Only for very small pigment particles the resulting spectra are close to spectra calculated supposing atomic mixing and assuming identical concentrations of all elements. Generally, a good fit can be achieved when evaluating spectra from structured materials assuming atomic mixing of all elements and laterally homogeneous depth distributions. However, the derived depth profiles are inaccurate by a factor of up to 3. The depth range affected by this structural ambiguity ranges from the surface to a depth of roughly 0.5-1 pigment particle diameters. Accurate quantitative evaluation of backscattering spectra from paintings therefore requires taking the correct microstructure of the paint layer into account.

  10. Elastic forward analysis using sup 7 Li ions A useful tool for H and light elements determination

    CERN Document Server

    Romero, S; Murillo, G; Berdejo, H M

    2002-01-01

    Films of CN sub x /Si, TiN sub x /AISI 304 and AlO sub x /Si were analyzed with sup 7 Li ions from 4.0 to 4.5 MeV and an experimental arrangement that, through detection of scattered projectiles and recoils by a single detector, allows quantification of H, light elements and heavier ones. A discussion is presented of the capabilities of Rutherford backscattering spectrometry (RBS) and conventional elastic recoil detection analysis (ERDA) compared to elastic forward analysis.

  11. Elastic recoil detection analysis of hydrogen in polymers

    Energy Technology Data Exchange (ETDEWEB)

    Winzell, T.R.H.; Whitlow, H.J. [Lund Univ. (Sweden); Bubb, I.F.; Short, R.; Johnston, P.N. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1996-12-31

    Elastic recoil detection analysis (ERDA) of hydrogen in thick polymeric films has been performed using 2.5 MeV He{sup 2+} ions from the tandem accelerator at the Royal Melbourne Institute of Technology. The technique enables the use of the same equipment as in Rutherford backscattering analysis, but instead of detecting the incident backscattered ion, the lighter recoiled ion is detected at a small forward angle. The purpose of this work is to investigate how selected polymers react when irradiated by helium ions. The polymers are to be evaluated for their suitability as reference standards for hydrogen depth profiling. Films investigated were Du Pont`s Kapton and Mylar, and polystyrene. 11 refs., 3 figs.

  12. Retrieval of ocean subsurface particulate backscattering coefficient from space-borne CALIOP lidar measurements.

    Science.gov (United States)

    Lu, Xiaomei; Hu, Yongxiang; Pelon, Jacques; Trepte, Charles; Liu, Katie; Rodier, Sharon; Zeng, Shan; Lucker, Patricia; Verhappen, Ron; Wilson, Jamie; Audouy, Claude; Ferrier, Christophe; Haouchine, Said; Hunt, Bill; Getzewich, Brian

    2016-12-12

    A new approach has been proposed to determine ocean subsurface particulate backscattering coefficient bbp from CALIOP 30° off-nadir lidar measurements. The new method also provides estimates of the particle volume scattering function at the 180° scattering angle. The CALIOP based layer-integrated lidar backscatter and particulate backscattering coefficients are compared with the results obtained from MODIS ocean color measurements. The comparison analysis shows that ocean subsurface lidar backscatter and particulate backscattering coefficient bbp can be accurately obtained from CALIOP lidar measurements, thereby supporting the use of space-borne lidar measurements for ocean subsurface studies.

  13. Intercomparison of ion beam analysis software for the simulation of backscattering spectra from two-dimensional structures

    Science.gov (United States)

    Mayer, M.; Malinský, P.; Schiettekatte, F.; Zolnai, Z.

    2016-10-01

    The codes RBS-MAST, STRUCTNRA, F95-Rough and CORTEO are simulation codes for ion beam analysis spectra from two- or three-dimensional sample structures. The codes were intercompared in a code-code comparison using an idealized grating structure and by comparison to experimental data from a silicon grating on tantalum interlayer. All codes are in excellent agreement at higher incident energies and not too large energy losses. At lower incident energies, grazing angles of incidence and/or larger energy losses plural scattering effects play an increasing role. Simulation codes with plural scattering capabilities offer higher accuracy and better agreement to experimental results in this regime.

  14. Rutherford cable made of single-core MgB2 wires

    Science.gov (United States)

    Kopera, L.; Kováč, P.; Hušek, I.; Melišek, T.

    2013-12-01

    A flexible Rutherford cable stranded from twelve single-core MgB2 wires has been made. Individual MgB2/Ti/Cu/Monel strands of the cable were prepared by wire drawing down to an outer diameter of 300 μm. The strands were wound into the rectangular Rutherford-type cable with the aid of a back-twist cabling machine. The transposition length of the cable, shaped into the final overall dimensions of 0.54 mm × 2 mm, is 20 mm. In order to analyse the electrical and mechanical properties, short specimens of a heat-treated reference sample (as-drawn wire), wire strand extracted from the cable, as well as Rutherford cable specimens were prepared and measured. It was found that final cold forming of the cable by a rolling die increased the critical current density of individual strands by 65% in comparison to drawn ones. Consequently, the critical current of the Rutherford cable is considerably higher than the 12Ic of the reference sample. Bending stress applied to the Rutherford cable has shown that critical current degradation starts below a diameter of 35 mm, which suggests using the cable for the construction of small-scale windings and applications where low bending diameters are required.

  15. Materials analysis fast ions

    CERN Document Server

    Denker, A; Rauschenberg, J; Röhrich, J; Strub, E

    2006-01-01

    Materials analysis with ion beams exploits the interaction of ions with the electrons and nuclei in the sample. Among the vast variety of possible analytical techniques available with ion beams we will restrain to ion beam analysis with ion beams in the energy range from one to several MeV per mass unit. It is possible to use either the back-scattered projectiles (RBS – Rutherford Back Scattering) or the recoiled atoms itself (ERDA – Elastic Recoil Detection Analysis) from the elastic scattering processes. These techniques allow the simultaneous and absolute determination of stoichiometry and depth profiles of the detected elements. The interaction of the ions with the electrons in the sample produces holes in the inner electronic shells of the sample atoms, which recombine and emit X-rays characteristic for the element in question. Particle Induced X-ray Emission (PIXE) has shown to be a fast technique for the analysis of elements with an atomic number above 11.

  16. Detection of Coaxial Backscattered Electrons in SEM

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    We present a coaxial detection of the backscattered electrons in SEM. The lens-aperture has been used to filter in energy and focus the backscattered electrons. This particular geometry allows us to eliminate the iow energy backscattered electrons and collect the backscattered electrons, which are backscattered close to the incident beam orientation. The main advantage of this geometry is adapted to topographic contrast attenuation and atomic number contrast enhancement. Thus this new SEM is very suitable to analyze the material composition.

  17. Differential scattering cross-sections, inelastic energy losses and ion fractions in backscattering of keV He sup + ions from monolayer metal adsorbates on solid surfaces measured by means of CAICISS

    CERN Document Server

    Kishi, N

    2002-01-01

    Energy spectra of He atoms and He sup + ions backscattered at an angle of approx 180 deg. by monolayer metal adsorbates (Ag, Sn, Sb, Pb and Bi) on the Si(1 1 1)-sq root 3x sq root 3 surfaces and monolayer Si atoms on the graphite surface have been measured by means of the coaxial impact collision ion scattering spectroscopy technique combined with low energy electron diffraction, Auger electron spectroscopy and Rutherford backscattering spectrometry techniques in the energy range from 0.5 to 3.0 keV. It is found from their data analysis that the ratios of the experimental scattering cross-section to the magic formula of the Thomas-Fermi cross-section for different adsorbates deviate from unity: for instance 1.2 for Si, 0.8 for Ag, 1.5 for Sn, 1.2 for Sb, 1.2 for Pb and 1.6 for Bi. It is also found that the average inelastic energy loss for Si increases monotonically with increasing the incident energy, while those for the other adsorbates increase stepwisely at around 1.0 keV and thereafter gradually. Moreove...

  18. 3D Backscatter Imaging System

    Science.gov (United States)

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

    2016-01-01

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

  19. Physics for Teachers: Understanding Physics: David Cassidy, Gerald Holton, & James Rutherford

    Science.gov (United States)

    Hubisz, John L.

    2009-11-01

    Physics for Teachers: Understanding Physics, by David Cassidy, Gerald Holton, & James Rutherford and published by Springer Verlag, New York, NY 10010 (2002), pp. xxiii + 851 80.00 hardback. ISBN 0-387-98756-8. Student Guide & Instructor Guide are also available. The text and Instructor Guide are available online at http://www.dcassidybooks.com/up.html

  20. Turning Plastic into Gold: An Analogy to Demonstrate The Rutherford Gold Foil Experiment

    Science.gov (United States)

    Gregory, Robert B.

    2007-01-01

    The Rutherford-Geiger-Marsden gold foil experiment is demonstrated to give students a useful mental image of the concept or principle of chemistry. The experiment shows students that in a short time one unexpected result can change the way science looks at the world.

  1. Rutherford B. Hayes Presidential Center Library and Archives: Patron Use of Collections and Services.

    Science.gov (United States)

    Grove, Myrna J.

    The Rutherford B. Hayes Library opened in 1916, when the building in Fremont, Ohio was dedicated as the first presidential library and museum. The library's original purpose was to preserve the 12,000 volume personal library of President Hayes along with archival material from his careers in law, the military, and politics. This was a radical idea…

  2. Substance Abuse among Health-Care Professionals in Rutherford and Surrounding Counties.

    Science.gov (United States)

    Edwards, Sherri Reid; Heritage, Jeannette G.

    Drug abuse is a serious problem in today's work force. It is found in every occupation, from the entry-level employee to the chief executive officer. Among health care professionals alcohol is the number-one substance abused, prescription drugs are second, and cocaine is third. Substance abuse among health-care professionals in Rutherford,…

  3. S.T.E.P. in Bay County. The Rutherford Project.

    Science.gov (United States)

    Florida State Dept. of Education, Tallahassee. Office of Environment Education.

    This document presents an explanation, illustration, and evaluation of a Students Toward Environmental Participation (S.T.E.P.) Project at Rutherford High School in Bay County, Florida. The main objective of this S.T.E.P. Project was to train high school students to teach environmental awareness activities to elementary students. This booklet…

  4. X-ray backscatter imaging

    Science.gov (United States)

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

    2008-04-01

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

  5. Fundamentals of Acoustic Backscatter Imagery

    Science.gov (United States)

    2011-09-20

    41 6.12 Geocoding ...47 7.6 Errors in Geocoding .............................................................................................................. 47...h = z - R cos6 (39a) and x = rt sin6. (39b) 6.12 Geocoding Acoustic backscatter imagery data are collected by recording the across-track signals

  6. Nodule bottom backscattering study using multibeam echosounder

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Raju, Y.S.N.; Nair, R.R.

    A study is carried out to observe the angular dependence of backscattering strength at nodule area where grab sample and photographic data is available. Theoretical study along with the experimentally observed data shows that the backscattering...

  7. Backscatter B [8101]--Offshore Bolinas, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bolinas map area, California. Backscatter data are provided as separate grids...

  8. Backscatter A [8101]--Offshore San Gregorio, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3306 presents data for the acoustic-backscatter map (see sheet 3, SIM 3306) of the Offshore of San Gregorio map area, California. Backscatter data...

  9. BackscatterA [8101]--Offshore Pacifica, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pacifica map area, California. Backscatter data are provided as two separate grids...

  10. Backscatter C [7125]--Offshore Bolinas, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bolinas map area, California. Backscatter data are provided as separate grids...

  11. BackscatterB [7125]--Offshore Pacifica, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pacifica map area, California. Backscatter data are provided as two separate grids...

  12. Backscatter A [8101]--Offshore Bolinas, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bolinas map area, California. Backscatter data are provided as separate grids...

  13. Backscatter D [Snippets]--Offshore Bolinas, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bolinas map area, California. Backscatter data are provided as separate grids...

  14. BackscatterA [8101]--Offshore Pacifica, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pacifica map area, California. Backscatter data are provided as two separate grids...

  15. BackscatterB [7125]--Offshore Pacifica, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pacifica map area, California. Backscatter data are provided as two separate grids...

  16. Backscatter [5m]--Offshore Monterey, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Monterey map area, California. Backscatter data are provided as separate grids...

  17. Backscatter E [Swath]--Offshore Bolinas, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bolinas map area, California. Backscatter data are provided as separate grids...

  18. Backscatter B [7125]--Offshore San Gregorio, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3306 presents data for the acoustic-backscatter map (see sheet 3, SIM 3306) of the Offshore of San Gregorio map area, California. Backscatter data...

  19. Backscatter [SWATH]--Offshore Santa Cruz, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Santa Cruz map area, California. Backscatter data are provided as three separate...

  20. Backscatter [SWATH]--Offshore Santa Cruz, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Santa Cruz map area, California. Backscatter data are provided as three separate...

  1. Backscatter [5m]--Offshore Monterey, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Monterey map area, California. Backscatter data are provided as separate grids...

  2. Backscatter C [7125]--Offshore Bolinas, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bolinas map area, California. Backscatter data are provided as separate grids...

  3. Backscatter A [8101]--Offshore Bolinas, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bolinas map area, California. Backscatter data are provided as separate grids...

  4. Backscatter B [8101]--Offshore Bolinas, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bolinas map area, California. Backscatter data are provided as separate grids...

  5. Backscatter D [Snippets]--Offshore Bolinas, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bolinas map area, California. Backscatter data are provided as separate grids...

  6. Elementary polarization properties in the backscattering configuration.

    Science.gov (United States)

    Arteaga, Oriol; Garcia-Caurel, Enric; Ossikovski, Razvigor

    2014-10-15

    In the normal incidence backscattering configuration, a polarimetric measurement always preserves the reciprocal symmetry. For a reciprocal Jones matrix, the number of elementary polarization properties is reduced from six to four. In this work, the physical interpretation of these properties is examined and they are compared with the equivalent polarization properties in transmission. It is found that, with the exception of natural optical activity, a polarimetric backreflection experiment can essentially provide the same type of information about the anisotropy of a medium as a transmission analysis, although transmission and backreflection information comes in a completely different form. Experimental examples are provided to illustrate the discussion.

  7. Data analysis of backscattering LIDAR system correlated with meteorological data; Analise de dados de sistema LIDAR de retroespalhamento correlacionada com dados meteorologicos

    Energy Technology Data Exchange (ETDEWEB)

    Uehara, Sandro Toshio

    2009-07-01

    In these last years, we had an increase in the interest in the monitoring of the effect of the human activity being on the atmosphere and the climate in the planet. The remote sensing techniques has been used in many studies, also related the global changes. A backscattering LIDAR system, the first of this kind in Brazil, has been used to provide the vertical profile of the aerosol backscatter coefficient at 532 nm up to an altitude of 4-6 km above sea level. In this study, data has was collected in the year of 2005. These data had been correlated with data of solar photometer CIMEL and also with meteorological data. The main results had indicated to exist a standard in the behavior of these meteorological data and the vertical distribution of the extinction coefficient gotten through LIDAR. In favorable periods of atmospheric dispersion, that is, rise of the temperature of associated air the fall of relative humidity, increase of the atmospheric pressure and low ventilation tax, was possible to determine with good precision the height of the Planetary Boundary Layer, as much through the vertical profile of the extinction coefficient how much through the technique of the vertical profile of the potential temperature. The technique LIDAR showed to be an important tool in the determination of the thermodynamic structure of the atmosphere, assisting to characterize the evolution of the CLP throughout the day, which had its good space and secular resolution. (author)

  8. Analysis of Terminal Velocity and VHF Backscatter of Precipitation Particles Using Chung-Li VHF Radar Combined with Ground-Based Disdrometer

    Directory of Open Access Journals (Sweden)

    Ching-Lun Su and Yen-Hsyang Chu

    2007-01-01

    Full Text Available The backscatter from precipitation particles observed by the vertically pointed antenna beam of the Chung-Li VHF radar and the drop size distributions measured by a ground-based disdrometer co-located at the radar site are analyzed and studied in this article. We find that the disdrometermeasured drop size distribution can be well approximated to a Gamma distribution. On the basis of this property and a power law approximation to the fallspeed-diameter relation VD = ADB, we derive the theoretical relation between terminal velocity VD and range-corrected VHF backscatter P of the precipitation particles. We find that the VD - P relation follows a power law in the form of VD = _ where _ _ both the functions of the precipitation parameters. Chu et al. (1999 first found that the relation between _ _ be empirically approximated to an exponential form of _ _ where _ a function of B and _ a factor associated with precipitation. In this article, under the assumptions of the Gamma distribution of the drop size distribution and the power-law relation between VD and D, we theoretically show that the analytical relation between _ _ follows an exponential form of _ _ where _ a function of the drop size distribution. The experimental results obtained by the Chung-Li VHF radar combined with the ground-based disdrometer measurements validate the exponential approximation to the _ _ The uses of the _ _ for the investigations of the rainfall rate and properties of drop size distribution are presented and discussed.

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

    Science.gov (United States)

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

    2010-10-01

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

  10. Hanle effect in coherent backscattering

    CERN Document Server

    Labeyrie, G; Müller, C A; Sigwarth, O; Delande, D; Kaiser, R

    2002-01-01

    We study the shape of the coherent backscattering (CBS) cone obtained when resonant light illuminates a thick cloud of laser-cooled rubidium atoms in presence of a homogenous magnetic field. We observe new magnetic field-dependent anisotropies in the CBS signal. We show that the observed behavior is due to the modification of the atomic radiation pattern by the magnetic field (Hanle effect in the excited state).

  11. Study of Transient Heat Transport Mechanisms in Superfluid Helium Cooled Rutherford-Cables

    CERN Document Server

    AUTHOR|(CDS)2100615

    The Large Hadron Collider leverages superconducting magnets to focus the particle beam or keep it in its circular track. These superconducting magnets are composed of NbTi-cables with a special insulation that allows superfluid helium to enter and cool the superconducting cable. Loss mechanisms, e.g. continuous random loss of particles escaping the collimation system heating up the magnets. Hence, a local temperature increase can occur and lead to a quench of the magnets when the superconductor warms up above the critical temperature. A detailed knowledge about the temperature increases in the superconducting cable (Rutherford type) ensures a secure operation of the LHC. A sample of the Rutherford cable has been instrumented with temperature sensors. Experiments with this sample have been performed within this study to investigate the cooling performance of the helium in the cable due to heat deposition. The experiment uses a superconducting coil, placed in a cryostat, to couple with the magnetic field loss m...

  12. Electron Backscatter Diffraction and Transmission Kikuchi Diffraction Analysis of an Austenitic Stainless Steel Subjected to Surface Mechanical Attrition Treatment and Plasma Nitriding.

    Science.gov (United States)

    Proust, Gwénaëlle; Retraint, Delphine; Chemkhi, Mahdi; Roos, Arjen; Demangel, Clemence

    2015-08-01

    Austenitic 316L stainless steel can be used for orthopedic implants due to its biocompatibility and high corrosion resistance. Its range of applications in this field could be broadened by improving its wear and friction properties. Surface properties can be modified through surface hardening treatments. The effects of such treatments on the microstructure of the alloy were investigated here. Surface Mechanical Attrition Treatment (SMAT) is a surface treatment that enhances mechanical properties of the material surface by creating a thin nanocrystalline layer. After SMAT, some specimens underwent a plasma nitriding process to further enhance their surface properties. Using electron backscatter diffraction, transmission Kikuchi diffraction, energy dispersive spectroscopy, and transmission electron microscopy, the microstructural evolution of the stainless steel after these different surface treatments was characterized. Microstructural features investigated include thickness of the nanocrystalline layer, size of the grains within the nanocrystalline layer, and depth of diffusion of nitrogen atoms within the material.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-07

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

  14. SU-E-T-235: Monte Carlo Analysis of the Dose Enhancement in the Scalp of Patients Due to Titanium Plate Backscatter During Post-Operative Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hardin, M; Elson, H; Lamba, M [University of Cincinnati, Cincinnati, OH (United States); Wolf, E [Precision Radiotherapy, West Chester, OH (United States); Warnick, R [UC Health Physicians, West Chester, OH (United States)

    2014-06-01

    Purpose: To quantify the clinically observed dose enhancement adjacent to cranial titanium fixation plates during post-operative radiotherapy. Methods: Irradiation of a titanium burr hole cover was simulated using Monte Carlo code MCNPX for a 6 MV photon spectrum to investigate backscatter dose enhancement due to increased production of secondary electrons within the titanium plate. The simulated plate was placed 3 mm deep in a water phantom, and dose deposition was tallied for 0.2 mm thick cells adjacent to the entrance and exit sides of the plate. These results were compared to a simulation excluding the presence of the titanium to calculate relative dose enhancement on the entrance and exit sides of the plate. To verify simulated results, two titanium burr hole covers (Synthes, Inc. and Biomet, Inc.) were irradiated with 6 MV photons in a solid water phantom containing GafChromic MD-55 film. The phantom was irradiated on a Varian 21EX linear accelerator at multiple gantry angles (0–180 degrees) to analyze the angular dependence of the backscattered radiation. Relative dose enhancement was quantified using computer software. Results: Monte Carlo simulations indicate a relative difference of 26.4% and 7.1% on the entrance and exit sides of the plate respectively. Film dosimetry results using a similar geometry indicate a relative difference of 13% and -10% on the entrance and exit sides of the plate respectively. Relative dose enhancement on the entrance side of the plate decreased with increasing gantry angle from 0 to 180 degrees. Conclusion: Film and simulation results demonstrate an increase in dose to structures immediately adjacent to cranial titanium fixation plates. Increased beam obliquity has shown to alleviate dose enhancement to some extent. These results are consistent with clinically observed effects.

  15. Lord Rutherford of Nelson, His 1908 Nobel Prize in Chemistry and Why He Didn't Get a Second Prize

    CERN Document Server

    Jarlskog, C

    2008-01-01

    "I have dealt with many different transformations with various periods of time, but the quickest that I have met was my own transformation in one moment from a physicist to a chemist." Ernest Rutherford (Nobel Banquet, 1908) This article is about how Ernest Rutherford (1871-1937) got the 1908 Nobel Prize in Chemistry and why he did not get a second Prize for his subsequent outstanding discoveries in physics, specially the discovery of the atomic nucleus and the proton. Who were those who nominated him and who did he nominate for the Nobel Prizes. In order to put the Prize issue into its proper context, I will briefly describe Rutherford's whereabouts. Rutherford, an exceptionally gifted scientist who revolutionized chemistry and physics, was moulded in the finest classical tradition. What were his opinions on some scientific issues such as Einstein's photon, uncertainty relations and the future prospects for atomic energy? What would he have said about the "Theory of Everything"?

  16. Backscatter coefficient estimation using tapers with gaps.

    Science.gov (United States)

    Luchies, Adam C; Oelze, Michael L

    2015-04-01

    When using the backscatter coefficient (BSC) to estimate quantitative ultrasound parameters such as the effective scatterer diameter (ESD) and the effective acoustic concentration (EAC), it is necessary to assume that the interrogated medium contains diffuse scatterers. Structures that invalidate this assumption can affect the estimated BSC parameters in terms of increased bias and variance and decrease performance when classifying disease. In this work, a method was developed to mitigate the effects of echoes from structures that invalidate the assumption of diffuse scattering, while preserving as much signal as possible for obtaining diffuse scatterer property estimates. Backscattered signal sections that contained nondiffuse signals were identified and a windowing technique was used to provide BSC estimates for diffuse echoes only. Experiments from physical phantoms were used to evaluate the effectiveness of the proposed BSC estimation methods. Tradeoffs associated with effective mitigation of specular scatterers and bias and variance introduced into the estimates were quantified. Analysis of the results suggested that discrete prolate spheroidal (PR) tapers with gaps provided the best performance for minimizing BSC error. Specifically, the mean square error for BSC between measured and theoretical had an average value of approximately 1.0 and 0.2 when using a Hanning taper and PR taper respectively, with six gaps. The BSC error due to amplitude bias was smallest for PR (Nω = 1) tapers. The BSC error due to shape bias was smallest for PR (Nω = 4) tapers. These results suggest using different taper types for estimating ESD versus EAC. © The Author(s) 2014.

  17. Source point calibration from an arbitrary electron backscattering pattern

    DEFF Research Database (Denmark)

    Lassen, Niels Christian Krieger

    1999-01-01

    Precise knowledge of the position of the source point is a requirement if electron backscattering patterns (EBSPs) are to be used for crystal orientation measurements or other types of measurements which demand a geometrical analysis of the patterns. Today, possibly the most popular method...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1987-10-01

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

  19. Gravitational Rutherford scattering and Keplerian orbits for electrically charged bodies in heterotic string theory

    Energy Technology Data Exchange (ETDEWEB)

    Villanueva, J.R. [Universidad de Valparaiso, Instituto de Fisica y Astronomia, Valparaiso (Chile); Centro de Astrofisica de Valparaiso, Valparaiso (Chile); Olivares, Marco [Universidad Diego Portales, Avenida Ejercito Libertador 441, Facultad de Ingenieria, Santiago (Chile)

    2015-11-15

    Properties of the motion of electrically charged particles in the background of the Gibbons-Maeda-Garfinkle-Horowitz-Strominger black hole is presented in this paper. Radial and angular motions are studied analytically for different values of the fundamental parameter. Therefore, gravitational Rutherford scattering and Keplerian orbits are analyzed in detail. Finally, this paper complements previous work by Fernando for null geodesics (Phys Rev D 85:024033, 2012), Olivares and Villanueva (Eur Phys J C 73:2659, 2013) and Blaga (Automat Comp Appl Math 22:41-48, 2013; Serb Astron 190:41, 2015) for time-like geodesics. (orig.)

  20. Gravitational Rutherford scattering and Keplerian orbits for electrically charged bodies in heterotic string theory

    Energy Technology Data Exchange (ETDEWEB)

    Villanueva, J. R., E-mail: jose.villanuevalob@uv.cl [Instituto de Física y Astronomía, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso (Chile); Centro de Astrofísica de Valparaíso, Gran Bretaña 1111, Playa Ancha, Valparaíso (Chile); Olivares, Marco, E-mail: marco.olivaresr@mail.udp.cl [Facultad de Ingeniería, Universidad Diego Portales, Avenida Ejército Libertador 441, Casilla 298–V, Santiago (Chile)

    2015-11-27

    Properties of the motion of electrically charged particles in the background of the Gibbons–Maeda–Garfinkle–Horowitz–Strominger black hole is presented in this paper. Radial and angular motions are studied analytically for different values of the fundamental parameter. Therefore, gravitational Rutherford scattering and Keplerian orbits are analyzed in detail. Finally, this paper complements previous work by Fernando for null geodesics (Phys Rev D 85:024033, 2012), Olivares and Villanueva (Eur Phys J C 73:2659, 2013) and Blaga (Automat Comp Appl Math 22:41–48, 2013; Serb Astron 190:41, 2015) for time-like geodesics.

  1. Gravitational Rutherford scattering and Keplerian orbits for electrically charged bodies in heterotic string theory

    CERN Document Server

    Villanueva, J R

    2015-01-01

    Properties of the motion of electrically charged particles in the background of the Gibbons-Maeda-Garfinkle-Horowitz-Strominger (GMGHS) black hole is presented in this paper. Radial and angular motion are studied analytically for different values of the fundamental parameter. Therefore, gravitational Rutherford scattering and Keplerian orbits are analysed in detail. Finally, this paper complements previous work by Fernando for null geodesics (Phys. Rev. D 85: 024033, 2012), Olivares & Villanueva (Eur. Phys. J. C 73: 2659, 2013) and Blaga (Automat. Comp. Appl. Math. 22, 41 (2013); Serb. Astron. J. 190, 41 (2015)) for time-like geodesics.

  2. A comparative analysis of extended water cloud model and backscatter modelling for above-ground biomass assessment in Corbett Tiger Reserve

    Science.gov (United States)

    Kumar, Yogesh; Singh, Sarnam; Chatterjee, R. S.; Trivedi, Mukul

    2016-04-01

    Forest biomass acts as a backbone in regulating the climate by storing carbon within itself. Thus the assessment of forest biomass is crucial in understanding the dynamics of the environment. Traditionally the destructive methods were adopted for the assessment of biomass which were further advanced to the non-destructive methods. The allometric equations developed by destructive methods were further used in non-destructive methods for the assessment, but they were mostly applied for woody/commercial timber species. However now days Remote Sensing data are primarily used for the biomass geospatial pattern assessment. The Optical Remote Sensing data (Landsat8, LISS III, etc.) are being used very successfully for the estimation of above ground biomass (AGB). However optical data is not suitable for all atmospheric/environmental conditions, because it can't penetrate through clouds and haze. Thus Radar data is one of the alternate possible ways to acquire data in all-weather conditions irrespective of weather and light. The paper examines the potential of ALOS PALSAR L-band dual polarisation data for the estimation of AGB in the Corbett Tiger Reserve (CTR) covering an area of 889 km2. The main focus of this study is to explore the accuracy of Polarimetric Scattering Model (Extended Water Cloud Model (EWCM) with respect to Backscatter model in the assessment of AGB. The parameters of the EWCM were estimated using the decomposition components (Raney Decomposition) and the plot level information. The above ground biomass in the CTR ranges from 9.6 t/ha to 322.6 t/ha.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-12-01

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

  4. A comparative study of RADAR Ka-band backscatter

    Science.gov (United States)

    Mapelli, D.; Pierdicca, N.; Guerriero, L.; Ferrazzoli, Paolo; Calleja, Eduardo; Rommen, B.; Giudici, D.; Monti Guarnieri, A.

    2014-10-01

    Ka-band RADAR frequency range has not yet been used for Synthetic Aperture Radar (SAR) from space so far, although this technology may lead to important applications for the next generation of SAR space sensors. Therefore, feasibility studies regarding a Ka-band SAR instrument have been started [1][2], for the next generation of SAR space sensors. In spite of this, the lack of trusted references on backscatter at Ka-band revealed to be the main limitation for the investigation of the potentialities of this technology. In the framework of the ESA project "Ka-band SAR backscatter analysis in support of future applications", this paper is aimed at the study of wave interaction at Ka-band for a wide range of targets in order to define a set of well calibrated and reliable Ka-band backscatter coefficients for different kinds of targets. We propose several examples of backscatter data resulting from a critical survey of available datasets at Ka-band, focusing on the most interesting cases and addressing both correspondences and differences. The reliability of the results will be assessed via a preliminary comparison with ElectroMagnetic (EM) theoretical models. Furthermore, in support of future technological applications, we have designed a prototypal software acting as a "library" of earth surface radar response. In our intention, the output of the study shall contribute to answer to the need of a trustworthy Ka-Band backscatter reference. It will be of great value for future technological applications, such as support to instrument analysis, design and requirements' definition (e.g.: Signal to Noise Ratio, Noise Equivalent Sigma Zero).

  5. Simulation of the cabling process for Rutherford cables: An advanced finite element model

    Science.gov (United States)

    Cabanes, J.; Garlasche, M.; Bordini, B.; Dallocchio, A.

    2016-12-01

    In all existing large particle accelerators (Tevatron, HERA, RHIC, LHC) the main superconducting magnets are based on Rutherford cables, which are characterized by having: strands fully transposed with respect to the magnetic field, a significant compaction that assures a large engineering critical current density and a geometry that allows efficient winding of the coils. The Nb3Sn magnets developed in the framework of the HL-LHC project for improving the luminosity of the Large Hadron Collider (LHC) are also based on Rutherford cables. Due to the characteristics of Nb3Sn wires, the cabling process has become a crucial step in the magnet manufacturing. During cabling the wires experience large plastic deformations that strongly modify the geometrical dimensions of the sub-elements constituting the superconducting strand. These deformations are particularly severe on the cable edges and can result in a significant reduction of the cable critical current as well as of the Residual Resistivity Ratio (RRR) of the stabilizing copper. In order to understand the main parameters that rule the cabling process and their impact on the cable performance, CERN has developed a 3D Finite Element (FE) model based on the LS-Dyna® software that simulates the whole cabling process. In the paper the model is presented together with a comparison between experimental and numerical results for a copper cable produced at CERN.

  6. Critical currents of Rutherford MgB2 cables compacted by two-axial rolling

    Science.gov (United States)

    Kopera, L.; Kováč, P.; Kulich, M.; Melišek, T.; Rindfleisch, M.; Yue, J.; Hušek, I.

    2017-01-01

    Two types of Rutherford cables made of two strand layers of commercial MgB2 wires manufactured by Hyper Tech Research, Inc. have been made. Flat rectangular cables consisting of 12 single-core MgB2/Nb/Cu10Ni, or 6-filaments MgB2/Nb/Cu strands, both of diameter 390 mewm, were assembled using a back-twist cabling machine with transposition length of 20 mm. In order to analyze impact of the cable compaction on critical currents, cables were two-axially rolled, each by a single step reduction of 3.5%-29.7% to thickness range of 0.775-0.62 mm. It was found that by increasing the packing factor (PF) of cable above 0.79, the critical current begins to increase. It is improved nearly two times up to the PF limit 0.89. Compaction over the PF limit introduced cable degradation and decrease of critical current. Bending tests applied to cables showed that critical current degradation starts below the bending diameter 120 mm for 6-filaments Cu sheath and 70 mm for single-core Cu10Ni sheath cable. Tensile tests showed similar irreversible strain values for the both types of cables. Rutherford cables assembled of single-core strands are promising for low field (2.7-4 T) applications where low bending diameters are required.

  7. Low coupling loss core-strengthened Bi 2212\\/Ag Rutherford cables

    CERN Document Server

    Collings, E W; Scanlan, R M; Dietderich, D R; Motowidlo, L R

    1999-01-01

    In a comprehensive "vertically integrated" program multifilamentary (MF) high temperature superconducting (HTSC) Bi:2212/Ag strand was fabricated using the powder-in-tube process and heat treated in oxygen by a modified standard $9 procedure. The reaction-heat-treatment (HT) was adjusted to maximize critical current (density), I/sub c/ (J /sub c/), as measured in various magnetic fields, B. A series of Rutherford cables was designed, each of which included a $9 metallic (Nichrome-80) core for strengthening and reduction of coupling loss. Prior to cable winding a series of tests examined the possibility of strand "poisoning" by the core during HT. Small model Rutherford cables were wound, $9 and after HT were prepared for I/sub c/(B) measurement and calorimetric measurement of AC loss and hence interstrand contact resistance I/sub c/(B). It was deduced that, if in direct contact with the strand during HT, the core $9 material can degrade the I/sub c/ of the cable; but steps can be taken to eliminate this probl...

  8. Aluminum strand coating for increasing the interstrand contact resistance in Rutherford type superconducting cables

    CERN Document Server

    Scheuerlein, C; Verweij, A; Bonasia, A; Oberli, L; Taborelli, M; Richter, R

    2009-01-01

    The interstrand contact resistance (Rc) in Rutherford type cables for fast cycling superconducting magnets must be sufficiently high in order to limit eddy current losses. The required value for Rc depends on the cable and magnet geometries and on the foreseen cycling rate, but is typically of the order of one mW. Such values can be reached with a dedicated strand coating or with a resistive internal cable barrier. As a possible candidate Al strand coatings have been tested. For a Rutherford type inner conductor cable of the Large Hadron Collider (LHC) made of Al coated strands Rc values higher than 500 Omega are achieved. The native Al2O3 oxide layer formed at ambient temperature in air is sufficient to reach this high contact resistance. A 6 h-200 °C oxidation heat treatment in air with 100% relative humidity further increases Rc to values above 600 μOmega . Due to the high thermal and mechanical stability of Al2O3 only a relatively moderate Rc drop of about 40 % is obtained during a 190 °C heat treatmen...

  9. Performance of a 14-T CuNb/Nb3Sn Rutherford coil with a 300 mm wide cold bore

    Science.gov (United States)

    Oguro, Hidetoshi; Watanabe, Kazuo; Awaji, Satoshi; Hanai, Satoshi; Ioka, Shigeru; Sugimoto, Masahiro; Tsubouchi, Hirokazu

    2016-08-01

    A large-bore 14-T CuNb/Nb3Sn Rutherford coil was developed for a 25 T cryogen-free superconducting magnet. The magnet consisted of a low-temperature superconducting (LTS) magnet of NbTi and Nb3Sn Rutherford coils, and a high-temperature superconducting magnet. The Nb3Sn Rutherford coil was fabricated by the react-and-wind method for the first time. The LTS magnet reached the designed operation current of 854 A without a training quench at a 1 h ramp rate. The central magnetic field generated by the LTS magnet was measured by a Hall sensor to be 14.0 T at 854 A in a 300 mm cold bore.

  10. Ion beam analysis of pottery from Teotihuacan, Mexico

    Science.gov (United States)

    Ontalba Salamanca, M. Á.; Ruvalcaba-Sil, J. L.; Bucio, L.; Manzanilla, L.; Miranda, J.

    2000-03-01

    This work presents the characterization of sherds and pottery paints from Teotihuacan, Mexico, belonging to the Mesoamerican Epiclassic (700-900 AD) and Postclassic (900-1521 AD) periods. A simultaneous analysis by Particle Induced X-ray Emission (PIXE) and Rutherford Backscattering Spectroscopy (RBS) was carried out to measure the elemental composition of pottery and clays sources of the Teotihuacan region. Also, a semiquantitative X-Ray Diffraction study (XRD) was performed to determine the mineralogical phases. From elemental and mineralogical composition, groups of local and foreign sherds were established. Results showed that the PIXE-RBS method combined with XRD proved to be a very powerful and general procedure for archaeological characterization. Moreover, non-vacuum differential PIXE analysis was carried out on colored regions of some representative vessels to study the layered structure of the paints-clay system.

  11. Averaging of Backscatter Intensities in Compounds

    Science.gov (United States)

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

    2002-01-01

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

  12. Intercomparisons of Lidar Backscatter Measurements and In-situ Data from GLOBE

    Science.gov (United States)

    Chudamani, S.; Spinhirne, James D.

    1992-01-01

    The Global Backscatter Experiment (GLOBE) took place during Nov. 1989 and May - Jun. 1990 and involved flight surveys of the Pacific region by the NASA DC-8 aircraft. The experimental instruments were lidars operating at wavelengths ranging from the visible to the thermal infrared and various optical particle counters for in-situ measurements. The primary motivation for GLOBE was the development of spaceborne wind sensing lidar. This paper will concern a comparison of direct backscatter measurements and backscatter calculated from particle counter data. Of special interest is that the particle measurements provided data on composition, and thus refractive index variation may be included in the analysis.

  13. Thin film depth profiling by ion beam analysis.

    Science.gov (United States)

    Jeynes, Chris; Colaux, Julien L

    2016-10-17

    The analysis of thin films is of central importance for functional materials, including the very large and active field of nanomaterials. Quantitative elemental depth profiling is basic to analysis, and many techniques exist, but all have limitations and quantitation is always an issue. We here review recent significant advances in ion beam analysis (IBA) which now merit it a standard place in the analyst's toolbox. Rutherford backscattering spectrometry (RBS) has been in use for half a century to obtain elemental depth profiles non-destructively from the first fraction of a micron from the surface of materials: more generally, "IBA" refers to the cluster of methods including elastic scattering (RBS; elastic recoil detection, ERD; and non-Rutherford elastic backscattering, EBS), nuclear reaction analysis (NRA: including particle-induced gamma-ray emission, PIGE), and also particle-induced X-ray emission (PIXE). We have at last demonstrated what was long promised, that RBS can be used as a primary reference technique for the best traceable accuracy available for non-destructive model-free methods in thin films. Also, it has become clear over the last decade that we can effectively combine synergistically the quite different information available from the atomic (PIXE) and nuclear (RBS, EBS, ERD, NRA) methods. Although it is well known that RBS has severe limitations that curtail its usefulness for elemental depth profiling, these limitations are largely overcome when we make proper synergistic use of IBA methods. In this Tutorial Review we aim to briefly explain to analysts what IBA is and why it is now a general quantitative method of great power. Analysts have got used to the availability of the large synchrotron facilities for certain sorts of difficult problems, but there are many much more easily accessible mid-range IBA facilities also able to address (and often more quantitatively) a wide range of otherwise almost intractable thin film questions.

  14. Multidirectional channeling analysis of epitaxial CdTe layers using an automatic RBS/channeling system

    Energy Technology Data Exchange (ETDEWEB)

    Wielunski, L.S.; Kenny, M.J. [CSIRO, Lindfield, NSW (Australia). Applied Physics Div.

    1993-12-31

    Rutherford Backscattering Spectrometry (RBS) is an ion beam analysis technique used in many fields. The high depth and mass resolution of RBS make this technique very useful in semiconductor material analysis [1]. The use of ion channeling in combination with RBS creates a powerful technique which can provide information about crystal quality and structure in addition to mass and depth resolution [2]. The presence of crystal defects such as interstitial atoms, dislocations or dislocation loops can be detected and profiled [3,4]. Semiconductor materials such as CdTe, HgTe and Hg+xCd{sub 1-x}Te generate considerable interest due to applications as infrared detectors in many technological areas. The present paper demonstrates how automatic RBS and multidirectional channeling analysis can be used to evaluate crystal quality and near surface defects. 6 refs., 1 fig.

  15. Observation of transverse coherent backscattering in disordered photonic structures

    CERN Document Server

    Brake, Sebastian; Leykam, Daniel; Desyatnikov, Anton; Denz, Cornelia

    2015-01-01

    We report on the experimental observation of weak localization in an optically induced disordered (2+1)-dimensional photonic structure. Our flexible method of optical induction is applied with a nondiffracting random intensity distribution. We focus on the analysis of a statistical output spectrum for many probe events with variance of the incoming beam's transverse spatial frequency. For particular spatial frequencies we find considerable signatures of transverse coherent backscattering.

  16. Stimulated Raman backscattering at high laser intensities

    Energy Technology Data Exchange (ETDEWEB)

    Skoric, M.M. [Vinca Inst. of Nuclear Sciences, Belgrade (Yugoslavia); Tajima, Toshiki; Sasaki, Akira; Maluckov, A.; Jovanovic, M.

    1998-03-01

    Signatures of Stimulated Raman backscattering of a short-pulse high-intensity laser interacting with an underdense plasma are discussed. We introduce a nonlinear three-wave interaction model that accounts for laser pump depletion and relativistic detuning. A mechanism is revealed based on a generic route to chaos, that predicts a progressive increase of the backscatter complexity with a growing laser intensity. Importance of kinetic effects is outlined and demonstrated in fluid-hybrid and particle simulations. As an application, we show that spectral anomalies of the backscatter, predicted by the above model, are consistent with recent sub-picosecond, high-intensity laser gas-target measurements at Livermore and elsewhere. Finally, a recently proposed scheme for generation of ultra-short, low-prepulse laser pulses by Raman backscattering in a thin foil target, is shown. (author)

  17. Current Redistribution around the Superconducting-to-normal Transition in Superconducting Nb-Ti Rutherford Cables

    CERN Document Server

    Willering, G P; ten Kate, H H J

    2008-01-01

    Sufficient thermal-electromagnetic stability against external heat sources is an essential design criterion for superconducting Rutherford cables, especially if operated close to the critical current. Due to the complex phenomena contributing to stability such as helium cooling, inter-strand current and heat transfer, its level is difficult to quantify. In order to improve our understanding, many stability tests were performed on different cable samples, each incorporating several point-like heaters. The current redistribution around the heat front is measured after inducing a local normal zone in one strand of the cable. By using voltage taps, expansion of the normal zone is monitored in the initially quenched strand as well as in adjacent strands. An array of Hall probes positioned at the cable edge is used to scan the selffield generated by the cable by which it becomes possible to estimate the inter-strand current transfer. In this paper it is demonstrated that two different stability regimes can be disti...

  18. CUDI A Model for Calculation of Electrodynamic and Thermal Behaviour of Superconducting Rutherford Cables

    CERN Document Server

    Verweij, A

    2006-01-01

    CUDI is the extended Fortran code to calculate the electrodynamic and thermal behaviour of any type of Rutherford cable subject to global and/or local variations in field, transport current, and external heat release. The internal parameters of the cable can be freely varied along the length and across the width, such as contact resistances, critical current, cooling rates etc. In this way, all the typical non-uniformities occurring in a cable, e.g. broken filaments, strand welds, cable joints, and edge degradation can be simulated. Also the characteristics of the strands in the cable can be varied from strand to strand. Heat flows through the matrix, through the interstrand contacts, and to the helium are incorporated, as well as the self-field and self- and mutual inductances between the strands. The main features and structure of the program will be discussed.

  19. Validation of automated supervised segmentation of multibeam backscatter data from the Chatham Rise, New Zealand

    Science.gov (United States)

    Hillman, Jess I. T.; Lamarche, Geoffroy; Pallentin, Arne; Pecher, Ingo A.; Gorman, Andrew R.; Schneider von Deimling, Jens

    2017-01-01

    Using automated supervised segmentation of multibeam backscatter data to delineate seafloor substrates is a relatively novel technique. Low-frequency multibeam echosounders (MBES), such as the 12-kHz EM120, present particular difficulties since the signal can penetrate several metres into the seafloor, depending on substrate type. We present a case study illustrating how a non-targeted dataset may be used to derive information from multibeam backscatter data regarding distribution of substrate types. The results allow us to assess limitations associated with low frequency MBES where sub-bottom layering is present, and test the accuracy of automated supervised segmentation performed using SonarScope® software. This is done through comparison of predicted and observed substrate from backscatter facies-derived classes and substrate data, reinforced using quantitative statistical analysis based on a confusion matrix. We use sediment samples, video transects and sub-bottom profiles acquired on the Chatham Rise, east of New Zealand. Inferences on the substrate types are made using the Generic Seafloor Acoustic Backscatter (GSAB) model, and the extents of the backscatter classes are delineated by automated supervised segmentation. Correlating substrate data to backscatter classes revealed that backscatter amplitude may correspond to lithologies up to 4 m below the seafloor. Our results emphasise several issues related to substrate characterisation using backscatter classification, primarily because the GSAB model does not only relate to grain size and roughness properties of substrate, but also accounts for other parameters that influence backscatter. Better understanding these limitations allows us to derive first-order interpretations of sediment properties from automated supervised segmentation.

  20. Core-suppressed AC loss and strand-moderated contact resistance in a Nb3Sn Rutherford cable

    NARCIS (Netherlands)

    Sumption, M.D.; Collings, E.W.; Scanlan, R.M.; Nijhuis, A.; Kate, ten H.H.J.

    1999-01-01

    Calorimetric measurements of AC loss and hence interstrand contact resistance (ICR), have been performed on two types of Rutherford cable wound with unplated Nb3Sn strand. One of the cable types was furnished with a thin core of AISI 316L stainless steel and the other was left uncored. The cables we

  1. Lord Rutherford of Nelson, his 1908 Nobel Prize in Chemistry, and why he didn't get a second prize

    Science.gov (United States)

    Jarlskog, Cecilia

    2008-11-01

    'I have dealt with many different transformations with various periods of time, but the quickest that I have met was my own transformation in one moment from a physicist to a chemist.' Ernest Rutherford (Nobel Banquet, 1908) This article is about how Ernest Rutherford (1871-1937) got the 1908 Nobel Prize in Chemistry and why he did not get a second Prize for his subsequent outstanding discoveries in physics, specially the discovery of the atomic nucleus and the proton. Who were those who nominated him and who did he nominate for the Nobel Prizes? In order to put the Prize issue into its proper context, I will briefly describe Rutherford's whereabouts. Rutherford, an exceptionally gifted scientist who revolutionized chemistry and physics, was moulded in the finest classical tradition. What were his opinions on some scientific issues such as Einstein's photon, uncertainty relations and the future prospects for atomic energy? What would he have said about the 'Theory of Everything'? Extended version of an invited talk presented at the conference 'Neutrino 2008', Christchurch, NZ, 25-31 May 2008

  2. Interstrand contact resistance and magnetization of Nb3Sn Rutherford cables with cores of different materials and widths

    NARCIS (Netherlands)

    Collings, E.W.; Sumption, M.D.; Dietderich, D.R.; Susner, M.; Krooshoop, H.J.G.; Nijhuis, A.

    2012-01-01

    Rutherford cables with cores of E-glass and S-glass woven tape and types AISI-316 and AISI-304 stainless steel (SS) ribbon were subjected to calorimetric AC loss measurement in transverse magnetic fields of amplitude 400 mT and frequencies of up to 90 mHz applied in the face-on (FO) and edge-on (EO)

  3. Ion beam analysis of ground coffee and roasted coffee beans

    Science.gov (United States)

    Debastiani, R.; dos Santos, C. E. I.; Yoneama, M. L.; Amaral, L.; Dias, J. F.

    2014-01-01

    The way that coffee is prepared (using roasted ground coffee or roasted coffee beans) may influence the quality of beverage. Therefore, the aim of this work is to use ion beam techniques to perform a full elemental analysis of packed roasted ground coffee and packed roasted coffee beans, as well as green coffee beans. The samples were analyzed by PIXE (particle-induced X-ray emission). Light elements were measured through RBS (Rutherford backscattering spectrometry) experiments. Micro-PIXE experiments were carried out in order to check the elemental distribution in the roasted and green coffee beans. In general, the elements found in ground coffee were Mg, P, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Rb and Sr. A comparison between ground coffee and grinded roasted beans shows significant differences for several elements. Elemental maps reveal that P and K are correlated and practically homogeneously distributed over the beans.

  4. Validation Test of Geant4 Simulation of Electron Backscattering

    CERN Document Server

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

    2015-01-01

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

  5. Present State of Electron Backscatter Diffraction and Prospective Developments

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-10-24

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

  6. Three-dimensional surface analysis system using a compact nuclear microprobe

    Science.gov (United States)

    Kishimoto, T.; Mimura, R.; Sawaragi, H.; Aihara, R.; Takai, M.

    1995-09-01

    A nondestructive three-dimensional Rutherford backscattering spectroscopy (RBS) and medium energy ion scattering (MEIS) analysis system with a compact 200 kV focused ion beam column has been developed. A liquid metal ion source (LMIS) such as lithium and/or beryllium (from Au/Si/Be eutectic alloy) was mounted on the short column. A high-vacuum sample chamber with a six-axis goniometer stage and an electrostatic toroidal analyzer for channeling and RBS analysis was connected to the acceleration column. The beam spot size was evaluated by microprobe-induced secondary electron image and a knife edge method using a thin gold pattern on a Si wafer. The beam current of 47 pA was obtained with a beam-spot diameter of 80 × 100 nm 2 for 400 keV Be ++ microprobes.

  7. International Atomic Energy Agency intercomparison of ion beam analysis software

    Science.gov (United States)

    Barradas, N. P.; Arstila, K.; Battistig, G.; Bianconi, M.; Dytlewski, N.; Jeynes, C.; Kótai, E.; Lulli, G.; Mayer, M.; Rauhala, E.; Szilágyi, E.; Thompson, M.

    2007-09-01

    Ion beam analysis (IBA) includes a group of techniques for the determination of elemental concentration depth profiles of thin film materials. Often the final results rely on simulations, fits and calculations, made by dedicated codes written for specific techniques. Here we evaluate numerical codes dedicated to the analysis of Rutherford backscattering spectrometry, non-Rutherford elastic backscattering spectrometry, elastic recoil detection analysis and non-resonant nuclear reaction analysis data. Several software packages have been presented and made available to the community. New codes regularly appear, and old codes continue to be used and occasionally updated and expanded. However, those codes have to date not been validated, or even compared to each other. Consequently, IBA practitioners use codes whose validity, correctness and accuracy have never been validated beyond the authors' efforts. In this work, we present the results of an IBA software intercomparison exercise, where seven different packages participated. These were DEPTH, GISA, DataFurnace (NDF), RBX, RUMP, SIMNRA (all analytical codes) and MCERD (a Monte Carlo code). In a first step, a series of simulations were defined, testing different capabilities of the codes, for fixed conditions. In a second step, a set of real experimental data were analysed. The main conclusion is that the codes perform well within the limits of their design, and that the largest differences in the results obtained are due to differences in the fundamental databases used (stopping power and scattering cross section). In particular, spectra can be calculated including Rutherford cross sections with screening, energy resolution convolutions including energy straggling, and pileup effects, with agreement between the codes available at the 0.1% level. This same agreement is also available for the non-RBS techniques. This agreement is not limited to calculation of spectra from particular structures with predetermined

  8. Integrating multibeam backscatter angular response, mosaic and bathymetry data for benthic habitat mapping.

    Directory of Open Access Journals (Sweden)

    Rozaimi Che Hasan

    Full Text Available Multibeam echosounders (MBES are increasingly becoming the tool of choice for marine habitat mapping applications. In turn, the rapid expansion of habitat mapping studies has resulted in a need for automated classification techniques to efficiently map benthic habitats, assess confidence in model outputs, and evaluate the importance of variables driving the patterns observed. The benthic habitat characterisation process often involves the analysis of MBES bathymetry, backscatter mosaic or angular response with observation data providing ground truth. However, studies that make use of the full range of MBES outputs within a single classification process are limited. We present an approach that integrates backscatter angular response with MBES bathymetry, backscatter mosaic and their derivatives in a classification process using a Random Forests (RF machine-learning algorithm to predict the distribution of benthic biological habitats. This approach includes a method of deriving statistical features from backscatter angular response curves created from MBES data collated within homogeneous regions of a backscatter mosaic. Using the RF algorithm we assess the relative importance of each variable in order to optimise the classification process and simplify models applied. The results showed that the inclusion of the angular response features in the classification process improved the accuracy of the final habitat maps from 88.5% to 93.6%. The RF algorithm identified bathymetry and the angular response mean as the two most important predictors. However, the highest classification rates were only obtained after incorporating additional features derived from bathymetry and the backscatter mosaic. The angular response features were found to be more important to the classification process compared to the backscatter mosaic features. This analysis indicates that integrating angular response information with bathymetry and the backscatter mosaic, along with

  9. Integrating multibeam backscatter angular response, mosaic and bathymetry data for benthic habitat mapping.

    Science.gov (United States)

    Che Hasan, Rozaimi; Ierodiaconou, Daniel; Laurenson, Laurie; Schimel, Alexandre

    2014-01-01

    Multibeam echosounders (MBES) are increasingly becoming the tool of choice for marine habitat mapping applications. In turn, the rapid expansion of habitat mapping studies has resulted in a need for automated classification techniques to efficiently map benthic habitats, assess confidence in model outputs, and evaluate the importance of variables driving the patterns observed. The benthic habitat characterisation process often involves the analysis of MBES bathymetry, backscatter mosaic or angular response with observation data providing ground truth. However, studies that make use of the full range of MBES outputs within a single classification process are limited. We present an approach that integrates backscatter angular response with MBES bathymetry, backscatter mosaic and their derivatives in a classification process using a Random Forests (RF) machine-learning algorithm to predict the distribution of benthic biological habitats. This approach includes a method of deriving statistical features from backscatter angular response curves created from MBES data collated within homogeneous regions of a backscatter mosaic. Using the RF algorithm we assess the relative importance of each variable in order to optimise the classification process and simplify models applied. The results showed that the inclusion of the angular response features in the classification process improved the accuracy of the final habitat maps from 88.5% to 93.6%. The RF algorithm identified bathymetry and the angular response mean as the two most important predictors. However, the highest classification rates were only obtained after incorporating additional features derived from bathymetry and the backscatter mosaic. The angular response features were found to be more important to the classification process compared to the backscatter mosaic features. This analysis indicates that integrating angular response information with bathymetry and the backscatter mosaic, along with their derivatives

  10. Reducing parametric backscattering by polarization rotation

    Science.gov (United States)

    Barth, Ido; Fisch, Nathaniel J.

    2016-10-01

    When a laser passes through underdense plasmas, Raman and Brillouin Backscattering can reflect a substantial portion of the incident laser energy. This is a major loss mechanism, for example, in employing lasers in inertial confinement fusion. However, by slow rotation of the incident linear polarization, the overall reflectivity can be reduced significantly. Particle in cell simulations show that, for parameters similar to those of indirect drive fusion experiments, polarization rotation reduces the reflectivity by a factor of 5. A general, fluid-model based analytical estimation for the reflectivity reduction agrees with simulations. However, in identifying the source of the backscatter reduction, it is difficult to disentangle the rotating polarization from the frequency separation based approach used to engineer the beam's polarization. Although the backscatter reduction arises similarly to other approaches that employ frequency separation, in the case here, the intensity remains constant in time.

  11. Predicting seabed properties from acoustic backscatter on the UK continental shelf (Invited)

    Science.gov (United States)

    McGonigle, C.; Collier, J.

    2010-12-01

    The relationship between backscatter imagery, sediment grain size and measures of biological community diversity are investigated using a quantitative approach at an aggregate extraction site in the Southern North Sea, UK. Previous work conducted at Oban in Scotland (Collier and Brown, 2005) showed the potential for estimating sediment grain size from first order backscatter statistics. In particular this study reported r2 correlation values of 0.531 between mean backscatter and mean sediment grain size, with r2=0.351 between standard deviation backscatter and sediment grain size sorting (n=19). Here we test these simple linear relationships in a different environment where the sediments are coarser and the degree of sorting is lower. We present the analysis of a dataset collected in 2008 off the coast of East Anglia, UK. Beam-time series backscatter imagery was acquired from a 300 kHz source MBES (Kongsberg Simard EM3000D), and ground-truth data obtained from a series of 100 Hamon and 16 Clamshell grabs processed for particle size analysis. Pixels were extracted from 32-bit backscatter imagery at 50 m2 window based on the ground-truth data locations. So far 19 of the 100 Hamon samples have been processed. These show a significant correlation between mean backscatter intensity and mean sediment grain size (r2=0.427). The level of agreement between standard deviation backscatter and grain size distribution however, was lower at r2=0.078. Correlation of univariate measures of biological diversity and mean backscatter were low for the 19 samples; the maximum observed value was r2=0.074 (Fisher’s diversity index). Relative to the standard deviation backscatter, the strongest correlation was r2=0.192 (Brillion’s). The analysis of the Clamshell samples is completed. In this case, the MBES backscatter imagery established a stronger positive correlation (r2=0.628) between the means. The level of agreement observed between the standard deviation of the backscatter and

  12. Heat Treatment Optimization of Rutherford Cable for a 15 T Nb3Sn Dipole Demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Barzi, Emanuela [barzi@fnal.gov

    2016-12-22

    FNAL has been developing a 15 T Nb3Sn dipole demonstrator for a future Very High Energy pp Collider based on an optimized 60-mm aperture 4-layer “cos-theta” coil. To increase magnet efficiency, the coil was graded by using two cables with same 15 mm width and different thicknesses made of two different Restacked Rod Process (RRP®) wires. Due to the non-uniform field distribution in dipole coils the maximum field in the inner coil will reach 15-16 T, whereas the maximum field in the outer coil is 12-13 T. In preparation for the 15 T dipole coil reaction, heat treatment studies were performed on strands extracted from these cables with the goal of achieving the best coil performance in the corresponding magnetic fields. In particular, the effect of maximum temperature and time on the cable critical current was studied to take into account actual variations of these parameters during coil reaction. In parallel and in collaboration with OST, development was performed on optimizing Nb3Sn RRP® wire design and layout. Index Terms— Accelerator magnet, critical current density, Nb3Sn strand, Rutherford cable.

  13. submitter Geometrical Behavior of $Nb_{3}Sn$ Rutherford Cables During Heat Treatment

    CERN Document Server

    Durante, Maria; Ferracin, Paolo; Manil, Pierre; Perez, Juan Carlos; Rifflet, Jean-Michel; Rondeaux, Francoise

    2016-01-01

    In $Nb_{3}Sn$ accelerator magnets, non-superconducting precursor cables are wound into their final coil shape and then heat treated at a high temperature to form the A15 superconducting phase. The growth of cable strands during reaction and the differential thermal dilatation in the coil components lead to both stress in the cable and geometrical deformations of the winding, with possible consequences on magnet performances. An experimental campaign on different types of Rutherford cables has been carried out at CEA Saclay, in collaboration with CERN, in order to measure cable dimension changes in all directions, with respect to cable configuration and winding geometry. A 700-mm-long versatile test bench has been designed for several cable topologies up to 22 mm in width. This paper describes the tooling and presents the results of the experimental campaign led on the cables, made of powder-in-tube and restacked-rod-process strands, of FRESCA2, a 13-T dipole magnet

  14. Characterization of Nb3Sn Rutherford cables for the LHC 11-T Dipole Magnet

    CERN Document Server

    Wuis, A J; Ballarino, A; Oberli, L; Ten Kate, H H J

    2013-01-01

    The so-called CERN-LHC DS upgrade relies on the use of 11 T dipole magnets. For these magnets 40 strands Nb3Sn type Rutherford cables based on 0.7 mm wires are being developed. Recently four samples of the cables were characterized in the CERN FRESCA cable test station. The critical current and the premature quench current due to magneto-thermal instability were measured at 1.9 K and 4.3 K in a background magnetic field between 0 and 9.6 T (the peak magnetic field on the conductor, including the self-field of the cable, ranges from ~ 2 T to ~ 12 T). Two cable samples were based on Powder-In-Tube (PIT) wire and two on Restacked-Rod-Process (RRP) wire. The PIT samples were identical and without a core in the cable while one of the RRP samples features a 25 μm thick stainless steel core. All cables samples tested have a width and a thickness of about 14.7 mm and 1.25 mm, respectively. Cables and sample holders were manufactured at CERN. In this paper we report and discuss the cable test results and compare them...

  15. Target studies for the neutrino factory at the Rutherford Appleton laboratory

    CERN Document Server

    Drumm, P V; Bennett, R

    2001-01-01

    Target studies at the Rutherford Appleton Laboratory have concentrated on studies of a solid heavy metal target. The suggestion to use a radiatively cooled target which rotates in beam was made shortly after the first NuFact workshop as a means of dissipating large amounts of power at a high temperature, and as an alternative to the proposed water-cooled rotating band and liquid metal jet targets. This paper examines the proposed drive scheme for the target ring, which uses induced currents and magnetic forces to both levitate and drive the target. Estimates of the power required to levitate and drive the target ring and the forces exerted on the moving ring as it enters the target capture solenoid are given. One of the principle concerns in the operation of a solid target is the severe shock stress experienced due to the impact of an intense energetic proton beam in a short time compared to the transit time of sound in the material. Calculations of the stresses induced in the target ring and their evolution ...

  16. Experimental results of current distribution in Rutherford-type LHC cables

    CERN Document Server

    Verweij, A P

    2000-01-01

    Current distribution among the wires of multi-strand superconducting cables is an important item for accelerator magnets. A non-uniform distribution could cause additional field distortions in the magnet bore and can as well be one of the reasons of premature quenching. Since two years electrical measurements on superconducting Rutherford-type cables are performed at CERN as part of the reception tests for the Large Hadron Collider (LHC). Cable samples of 2.4 m length are tested at currents up to 32 kA, temperatures around 1.9 and 4.3 K, and fields up to 10 T, applied perpendicularly as well as parallel to the broad face of the cable. Last year, an array of 24 Hall probes was installed in the test set-up in order to measure the self-field of the cable samples along one cable pitch. Each of the probes measures the local field generated by the current in the strands close by, and the results of the all probes reflect therefore the distribution of the strand currents. Experiments are done varying the applied fie...

  17. Matching an H{sup –} beam into a radio frequency quadrupole at Rutherford Appleton Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Gabor, C., E-mail: christoph.gabor@stfc.ac.uk; Faircloth, D. C.; Lawrie, S. R.; Letchford, A. P. [STFC, Rutherford Appleton Laboratory, Harwell, Didcot OX11 0QX (United Kingdom); Back, J. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2014-02-15

    A major component of work being carried out to upgrade the ISIS spallation neutron source at Rutherford Appleton Laboratory (RAL) is the Front End Test Stand (FETS). FETS is aimed at improving the luminosity of the linac, and consists of a Penning ion source, Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ), and Medium Energy Beam Transport (MEBT). It may serve as a first part of the accelerator chain providing a 60 mA, 3 MeV H{sup –} beam up to a 10% duty cycle. The current output of the source and the transmission of the LEBT are reasonable, but there are issues with the alignment to provide a centred beam matched into the acceptance of the RFQ. Improvements have been made to the post acceleration to address this problem. Measurements with a collimated beam have been performed to understand the behaviour of the solenoids and steerer magnets. Comparing these results with simulations proved that, besides possible mechanical imperfections of the ion source and post acceleration assembly, agreement can only be achieved if the magnetic fields are distorted.

  18. Interstrand and AC-loss measurements on Rutherford-type cables for accelerator magnet applications

    CERN Document Server

    Otmani, R; Tixador, P

    2001-01-01

    One of the main issues for particle accelerator magnets is the control of interstrand resistances. Too low resistances result in large coupling currents during ramping, which distort field quality, while too large resistances may prevent current redistribution among cable strands, resulting in degraded quench performance. In this paper, we review a series of interstrand resistance and AC-loss measurements performed on four Rutherford-type cables. The four cables have the same number of strands and similar outer dimensions, corresponding to LHC quadrupole cable specifications. The first cable is made from NbTi strands, coated with silver-tin alloy, the second one is made from bare Nb/sub 3/Sn strands, the third one is made also from bare Nb/sub 3/Sn strands but includes a 25- mu m-thick stainless steel core between the strand layers, and the last one is made from Nb/sub 3/Sn strands plated with chromium. To cross-check the two measurement types and assess their consistency, we compare the coupling-current time...

  19. Influence of strand surface condition on interstrand contact resistance and coupling loss in NbTi-wound Rutherford cables

    CERN Document Server

    Sumption, M D; Scanlan, R M; Nijhuis, A; ten Kate, H H J; Kim, S W; Wake, M; Shintomi, T

    1999-01-01

    Presented in this work are the results of directly measured and AC- loss-derived interstrand contact resistance (ICR) measurements performed magnetically or resistively on bare-Cu and coated-strand pairs, calorimetrically on $9 11-strand Rutherford cables wound with strands that had been coated with various metallic and insulating layers, and calorimetrically and magnetically on 28-strand Rutherford cables (LHC-type) wound with bare-Cu-, Ni-, and $9 stabrite-plated strands. Comparisons are made of the effects of various conditions of heat treatment, HT (time and temperature), and pressure (applied during HT and then either maintained or re-applied during measurement). The $9 resulting ICRs are compared and interpreted in terms of the oxide layer on the strand coating and its response to curing conditions. (66 refs).

  20. Heat transfer through Rutherford superconducting cable with novel pattern of polyimide electrical insulation in pressurized superfluid helium environment

    Science.gov (United States)

    Chorowski, Maciej; Polinski, Jaroslaw; Strychalski, Michal

    2012-06-01

    Future LHC accelerator luminosity upgrade will increase a beam losses heat deposition in the superconducting magnet coils. Main barrier of the heat evacuation from the coils made of Rutherford type cables is a cable electrical insulation. The insulation is made of polyimide tapes wrapped around the cable in a special configuration. Presently used insulation wrapping schemes constitute very good electrical insulation with relatively low heat transport ability. Therefore a new insulation wrapping schemes with enhanced helium permeability and adequate dielectric properties have been developed at CERN. An experimental comparative study of heat transfer perpendicular to the Rutherford type cable, for an old and new insulation wrapping schemes have been accomplished at Wroclaw University of Technology. The tests have been performed in pressurized superfluid helium conditions, and at 60 MPa of the sample applied external pressure simulating the Lorentz forces. This paper presents the measurements methodology and gives experimental results.

  1. Incidence angle normalization of radar backscatter data

    Science.gov (United States)

    NASA’s Soil Moisture Passive Active (SMAP) satellite (~2014) will include a radar system that will provide L-band multi-polarization backscatter at a constant incidence angle of 40º. During the pre-launch phase of the project there is a need for observations that will support the radar-based soil mo...

  2. Backscatter nephelometer to calibrate scanning lidar

    Science.gov (United States)

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

    2008-01-01

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

  3. IBA analysis and corrosion resistance of TiAlPtN/TiAlN/TiAl multilayer films deposited over a CoCrMo using magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Canto, C.E., E-mail: carloscanto2012@yahoo.com.mx [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 México D.F. (Mexico); Andrade, E.; Lucio, O. de; Cruz, J.; Solís, C. [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 México D.F. (Mexico); Rocha, M.F. [ESIME-Z, IPN, U.P. ALM, Gustavo A. Madero, C.P. 07738 México D.F. (Mexico); Alemón, B. [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, J. Guadalupe Zuno 48, Los Belenes, Zapopan, Jalisco 45101 (Mexico); Tecnológico de Monterrey, Av. General Ramón Corona 2514, Col. Nuevo México, Zapopan, Jalisco 45201 (Mexico); Flores, M. [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, J. Guadalupe Zuno 48, Los Belenes, Zapopan, Jalisco 45101 (Mexico); Huegel, J.C. [Tecnológico de Monterrey, Av. General Ramón Corona 2514, Col. Nuevo México, Zapopan, Jalisco 45201 (Mexico)

    2016-03-15

    The corrosion resistance and the elemental profile of multilayer coatings of TiAlPtN/TiAlN/TiAl synthesized by Physical Vapor Deposition (PVD) reactive magnetron sputtering over a CoCrMo alloy substrate in 10 periods of 30 min each were analyzed and compared to those of the substrate alone and to that of a TiAlPtN single layer coating of the same thickness. The objective of the present work was to create multilayers with different amounts of Pt to enhance the corrosion resistance of a biomedical alloy of CoCrMo. Corrosion tests were performed using Simulated Body Fluid (SBF) using potentiodynamic polarization tests at typical body temperature. The elemental composition and thickness of the coatings were evaluated with the combination of two ion beam analysis (IBA) techniques: a Rutherford Backscattering Spectroscopy (RBS) with alpha beam and a Nuclear Reaction Analysis with a deuteron beam.

  4. Backscatter A [8101]--Offshore of Tomales Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Tomales Point map area, California. Backscatter data are provided as separate...

  5. Backscatter C [Swath]--Offshore of Bodega Head, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bodega Head map area, California. Backscatter data are provided as separate...

  6. BackscatterA [8101]--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pigeon Point map area, California. Backscatter data are provided as three separate...

  7. Preliminary backscatter results from the hydrosweep multibeam system

    Digital Repository Service at National Institute of Oceanography (India)

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

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

  8. Backscatter A [8101]--Offshore of Tomales Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Tomales Point map area, California. Backscatter data are provided as separate...

  9. Backscatter C [8101]--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate...

  10. BackscatterA [8101]--Offshore Scott Creek, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Scott Creek map area, California. Backscatter data are provided as three separate...

  11. BackscatterB [7125]--Offshore Scott Creek, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Scott Creek map area, California. Backscatter data are provided as three separate...

  12. BackscatterB [EM300]--Offshore Aptos, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Aptos map area, California. Backscatter data are provided as two separate grids...

  13. BackscatterB [7125]--Offshore Scott Creek, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Scott Creek map area, California. Backscatter data are provided as three separate...

  14. Backscatter A [8101]--Offshore of Fort Ross, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Fort Ross map area, California. Backscatter data are provided as separate grids...

  15. Backscatter A [8101]--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate...

  16. BackscatterB [EM300]--Offshore Aptos, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Aptos map area, California. Backscatter data are provided as two separate grids...

  17. Backscatter A [8101]--Offshore of Bodega Head, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bodega Head map area, California. Backscatter data are provided as separate...

  18. Backscatter C [8101]--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate...

  19. Backscatter D [USGS]--Offshore of Tomales Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Tomales Point map area, California. Backscatter data are provided as separate...

  20. Backscatter C [Swath]--Offshore of Bodega Head, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bodega Head map area, California. Backscatter data are provided as separate...

  1. BackscatterC [SWATH]--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pigeon Point map area, California. Backscatter data are provided as three separate...

  2. Backscatter C [Swath]--Offshore of Tomales Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Tomales Point map area, California. Backscatter data are provided as separate...

  3. Backscatter B [7125]--Offshore of Tomales Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Tomales Point map area, California. Backscatter data are provided as separate...

  4. BackscatterA [SWATH]--Offshore Aptos, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Aptos map area, California. Backscatter data are provided as two separate grids...

  5. Backscatter A [8101]--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Drakes bay and Vicinity map area, California. Backscatter data are provided as separate grids...

  6. BackscatterB [7125]--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pigeon Point map area, California. Backscatter data are provided as three separate...

  7. Backscatter A [8101]--Offshore Half Moon Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Half Moon Bay map area, California. Backscatter data are provided as two...

  8. Backscatter B [8101]--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate...

  9. Backscatter A [8101]--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate...

  10. BackscatterC [7125]--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Monterey Canyon and Vicinity map area, California. Backscatter data are provided as separate...

  11. Backscatter D [7125]--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate...

  12. BackscatterC [SWATH]--Offshore Scott Creek, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Scott Creek map area, California. Backscatter data are provided as three separate...

  13. Backscatter B [7125]--Offshore of Fort Ross, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Fort Ross map area, California. Backscatter data are provided as separate grids...

  14. Backscatter C [Swath]--Offshore of Fort Ross, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Fort Ross map area, California. Backscatter data are provided as separate grids...

  15. Backscatter B [7125]--Offshore of Bodega Head, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bodega Head map area, California. Backscatter data are provided as separate...

  16. Backscatter B [Swath]--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Drakes bay and Vicinity map area, California. Backscatter data are provided as separate grids...

  17. Backscatter A [8101]--Offshore of Fort Ross, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Fort Ross map area, California. Backscatter data are provided as separate grids...

  18. BackscatterA [8101]--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pigeon Point map area, California. Backscatter data are provided as three separate...

  19. BackscatterB [7125]--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pigeon Point map area, California. Backscatter data are provided as three separate...

  20. BackscatterB [EM300]--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Monterey Canyon and Vicinity map area, California. Backscatter data are provided as separate...

  1. Backscatter B [7125]--Offshore of Fort Ross, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Fort Ross map area, California. Backscatter data are provided as separate...

  2. Backscatter C [Swath]--Offshore of Fort Ross, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Fort Ross map area, California. Backscatter data are provided as separate...

  3. Backscatter A [8101]--Offshore of Fort Ross, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Fort Ross map area, California. Backscatter data are provided as separate...

  4. Backscatter C [Swath]--Offshore of Fort Ross, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Fort Ross map area, California. Backscatter data are provided as separate grids...

  5. Backscatter C [7125]--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Drakes bay and Vicinity map area, California. Backscatter data are provided as separate grids...

  6. BackscatterC [SWATH]--Offshore Pigeon Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Pigeon Point map area, California. Backscatter data are provided as three separate...

  7. Backscatter B [8101]--Offshore of San Francisco, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of San Francisco map area, California. Backscatter data are provided as separate...

  8. Backscatter A [8101]--Offshore of Bodega Head, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bodega Head map area, California. Backscatter data are provided as separate...

  9. Backscatter B [7125]--Offshore Half Moon Bay, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Half Moon Bay map area, California. Backscatter data are provided as two...

  10. BackscatterA [8101]--Offshore Scott Creek, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Scott Creek map area, California. Backscatter data are provided as three separate...

  11. BackscatterC [SWATH]--Offshore Scott Creek, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Scott Creek map area, California. Backscatter data are provided as three separate...

  12. BackscatterA [SWATH]--Offshore Aptos, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Offshore of Aptos map area, California. Backscatter data are provided as two separate grids...

  13. BackscatterC [7125]--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Monterey Canyon and Vicinity map area, California. Backscatter data are provided as separate...

  14. BackscatterB [EM300]--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Monterey Canyon and Vicinity map area, California. Backscatter data are provided as separate...

  15. Backscatter B [7125]--Offshore of Tomales Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Tomales Point map area, California. Backscatter data are provided as separate...

  16. Backscatter A [8101]--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Drakes bay and Vicinity map area, California. Backscatter data are provided as separate grids...

  17. Backscatter C [Swath]--Offshore of Tomales Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Tomales Point map area, California. Backscatter data are provided as separate...

  18. Backscatter C [7125]--Drakes Bay and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Drakes bay and Vicinity map area, California. Backscatter data are provided as separate grids...

  19. Backscatter B [7125]--Offshore of Bodega Head, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Bodega Head map area, California. Backscatter data are provided as separate...

  20. AAAS News: Questions of Science Literacy Addressed by Rutherford/AAAS; 1982 Exhibit; Energy and Health to Be Discussed in Berkeley; Short Courses at Pacific Division, Annual Meeting.

    Science.gov (United States)

    Science, 1981

    1981-01-01

    Presents the views of F. James Rutherford concerning the status of science education and his role as advisor on science education to the Board of Directors of the American Association for the Advancement of Science. (SK)

  1. The ion velocity distribution of tokamak plasmas: Rutherford scattering at TEXTOR

    Energy Technology Data Exchange (ETDEWEB)

    Tammen, H.F.

    1995-01-10

    One of the most promising ways to gererate electricity in the next century on a large scale is nuclear fusion. In this process two light nuclei fuse and create a new nucleus with a smaller mass than the total mass of the original nuclei, the mass deficit is released in the form of kinetic energy. Research into this field has already been carried out for some decades now, and will have to continue for several more decades before a commercially viable fusion reactor can be build. In order to obtain fusion, fuels of extremely high temperatures are needed to overcome the repulsive force of the nuclei involved. Under these circumstances the fuel is fully ionized: it consists of ions and electrons and is in the plasma state. The problem of confining such a hot substance is solved by using strong magnetic fields. One specific magnetic configuration, in common use, is called the tokamak. The plasma in this machine has a toroidal, i.e. doughnut shaped, configuration. For understanding the physical processes which take place in the plasma, a good temporally and spatially resolved knowledge of both the ion and electron velocity distribution is required. The situation concerning the electrons is favourable, but this is not the case for the ions. To improve the existing knowledge of the ion velocity distribution in tokamak plasmas, a Rutherford scattering diagnostic (RUSC), designed and built by the FOM-Institute for Plasmaphysics `Rijnhuizen`, was installed at the TEXTOR tokamak in Juelich (D). The principle of the diagnostic is as follows. A beam of monoenergetic particles (30 keV, He) is injected vertically into the plasma. A small part of these particles collides elastically with the moving plasma ions. By determining the energy of a scattered beam particle under a certain angle (7 ), the initial velocity of the plasma ion in one direction can be computed. (orig./WL).

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

    Science.gov (United States)

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

    2016-07-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2016-01-01

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

  4. Study of new sheep bone and Zn/Ca ratio around TiAlV screw: PIXE-RBS analysis

    Energy Technology Data Exchange (ETDEWEB)

    Guibert, G. [Haute Ecole Arc Ingenierie, IMA-Arc-NEODE, 17 Eplatures-Grise, CH-2300 La Chaux-de-Fonds (Switzerland)], E-mail: geoffroy.guibert@he-arc.ch; Munnik, F. [Haute Ecole Arc Ingenierie, IMA-Arc-NEODE, 17 Eplatures-Grise, CH-2300 La Chaux-de-Fonds (Switzerland); Langhoff, J.D.; Von Rechenberg, B. [MSRU, Universitaet Zuerich, CH-8057 Zuerich (Switzerland); Buffat, Ph.A.; Laub, D. [EPFL-CIME, CH-1015 Lausanne (Switzerland); Faber, L.; Ducret, F. [DePuy ACE, CH-2400 Le Locle (Switzerland); Gerber, I. [Institute of Cell Biology, ETH Hoenggerberg, CH-8093 Zurich (Switzerland); Mikhailov, S. [Haute Ecole Arc Ingenierie, IMA-Arc-NEODE, 17 Eplatures-Grise, CH-2300 La Chaux-de-Fonds (Switzerland)

    2008-03-15

    This study reports on in vivo particle induced X-ray emission (PIXE) measurements combined with Rutherford backscattering spectroscopy (RBS) analyses of new remodeled sheep bone formed around TiAlV screws. The implants (screws) were anodized by a modified TiMax{sup TM} process. The interface between the implant and the bone was carefully investigated. [Zn]/[Ca] in-depth composition profiles as well as Ca, Fe elemental maps were recorded. The thickness of new bone formed around the screw reached 300-400 {mu}m. Osteon and Osteoid phases were identified in the new bone. A higher [Zn]/[Ca] ratio was observed in the new bone as compared to the mature bone. Blood vessels were observed in the bone in close contact with the screw. This study shows the potential of ion beam analysis for biological and biomedical characterization.

  5. Characterization of pre-Hispanic pottery from Teotihuacan, Mexico, by a combined PIXE-RBS and XRD analysis

    Science.gov (United States)

    Ruvalcaba-Sil, J. L.; Ontalba Salamanca, M. A.; Manzanilla, L.; Miranda, J.; Cañetas Ortega, J.; López, C.

    1999-04-01

    A combined analysis of IBA techniques (Proton Induced X-ray Emission (PIXE) and Rutherford Backscattering Spectroscopy (RBS)) and a complementary study by X-ray Diffraction (XRD) were performed to characterize pottery corresponding to the Epiclassic period (A.D. 700-900) from Teotihuacan, Mexico. Elemental compositions of pottery samples were measured by simultaneous PIXE and RBS using 2.6 MeV protons. Red, white and brown pottery pigments were studied by non-vacuum PIXE and a proton beam of 3 MeV. The various mineralogical phases of the pottery were identified by XRD. From pottery elemental compositions and its mineralogical phases, some differences among the pottery samples and groups were established.

  6. Characterization of pre-Hispanic pottery from Teotihuacan, Mexico, by a combined PIXE-RBS and XRD analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ruvalcaba-Sil, J.L.; Ontalba Salamanca, M.A.; Manzanilla, L.; Miranda, J.; Canetas Ortega, J.; Lopez, C

    1999-04-02

    A combined analysis of IBA techniques (Proton Induced X-ray Emission (PIXE) and Rutherford Backscattering Spectroscopy (RBS)) and a complementary study by X-ray Diffraction (XRD) were performed to characterize pottery corresponding to the Epiclassic period (A.D. 700-900) from Teotihuacan, Mexico. Elemental compositions of pottery samples were measured by simultaneous PIXE and RBS using 2.6 MeV protons. Red, white and brown pottery pigments were studied by non-vacuum PIXE and a proton beam of 3 MeV. The various mineralogical phases of the pottery were identified by XRD. From pottery elemental compositions and its mineralogical phases, some differences among the pottery samples and groups were established.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-01

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

  8. Compositional analysis and depth profiling of thin film CrO{sub 2} by heavy ion ERDA and standard RBS: a comparison

    Energy Technology Data Exchange (ETDEWEB)

    Khamlich, S., E-mail: skhamlich@gmail.com [Nano-Sciences Laboratories, Materials Research Department, iThemba LABS, P.O. Box 722, Somerset West 7129 (South Africa); Department of Chemistry, Tshwane University of Technology, Private Bag X 680, Pretoria, 0001 (South Africa); The African Laser Centre, CSIR campus, P.O. Box 395, Pretoria (South Africa); Msimanga, M., E-mail: mandla@tlabs.ac.za [Nano-Sciences Laboratories, Materials Research Department, iThemba LABS, P.O. Box 722, Somerset West 7129 (South Africa); iThemba LABS Gauteng, Private Bag 11, WITS 2050, Johannesburg (South Africa); Pineda-Vargas, C.A. [Nano-Sciences Laboratories, Materials Research Department, iThemba LABS, P.O. Box 722, Somerset West 7129 (South Africa); Faculty of Health and Wellness Sciences, C.P.U.T., P.O. Box 1906, Bellville 7535 (South Africa); Nuru, Z.Y. [Nano-Sciences Laboratories, Materials Research Department, iThemba LABS, P.O. Box 722, Somerset West 7129 (South Africa); McCrindle, R. [Department of Chemistry, Tshwane University of Technology, Private Bag X 680, Pretoria, 0001 (South Africa); Maaza, M. [Nano-Sciences Laboratories, Materials Research Department, iThemba LABS, P.O. Box 722, Somerset West 7129 (South Africa); Department of Chemistry, Tshwane University of Technology, Private Bag X 680, Pretoria, 0001 (South Africa); The African Laser Centre, CSIR campus, P.O. Box 395, Pretoria (South Africa)

    2012-08-15

    Chromium dioxide (CrO{sub 2}) thin film has generated considerable interest in applied research due to the wide variety of its technological applications. It has been extensively investigated in recent years, attracting the attention of researchers working on spintronic heterostructures and in the magnetic recording industry. However, its synthesis is usually a difficult task due to its metastable nature and various synthesis techniques are being investigated. In this work a polycrystalline thin film of CrO{sub 2} was prepared by electron beam vaporization of Cr{sub 2}O{sub 3} onto a Si substrate. The polycrystalline structure was confirmed through XRD analysis. The stoichiometry and elemental depth distribution of the deposited film were measured by ion beam nuclear analytical techniques heavy ion elastic recoil detection analysis (ERDA) and Rutherford backscattering spectrometry (RBS), which both have relative advantage over non-nuclear spectrometries in that they can readily provide quantitative information about the concentration and distribution of different atomic species in a layer. Moreover, the analysis carried out highlights the importance of complementary usage of the two techniques to obtain a more complete description of elemental content and depth distribution in thin films. - Graphical abstract: Heavy ion elastic recoil detection analysis (ERDA) and Rutherford backscattering spectrometry (RBS) both have relative advantage over non-nuclear spectrometries in that they can readily provide quantitative information about the concentration and distribution of different atomic species in a layer. Highlights: Black-Right-Pointing-Pointer Thin films of CrO{sub 2} have been grown by e-beam evaporation of Cr{sub 2}O{sub 3} target in vacuum. Black-Right-Pointing-Pointer The composition was determined by heavy ion-ERDA and RBS. Black-Right-Pointing-Pointer HI-ERDA and RBS provided information on the light and heavy elements, respectively.

  9. Surface quality studies of high T$_{c}$ superconductors of the Hg , Tl and Hg$_{x}$Tl$_{1-x}$-families RBS and resonant C and O backscattering studies

    CERN Document Server

    Vantomme, A; Correia, J G; Bryntse, I; Johansson, L G; Loureiro, S M; Le Floc'h, S; Toulemonde, T; Bordet, P; Bougerol-Chaillout, C

    2002-01-01

    The composition, crystallinity, uniformity, purity, and thermal stability of cuprate superconductors have been studied by Rutherford backscattering and channeling spectrometry, and 3.045 MeV He$^{+}$ oxygen non-Rutherford resonant scattering. Further experiments have been performed with 1.75 MeV H$^{+}$carbon non-Rutherford resonant scattering. Three sets of samples were studied : HgBa$_{2}$CuO$_{(4+\\delta)}$ (Hg1201), Hg$_{x}$T1$_{1-x}$Ba$_{2}$Ca$_{2}$Cu$_{3}$O$_{(2n+\\delta)}$ (Hg,T1-1223) and T1$_{1.85}$Ba$_{2}$CuO$_{6}$/LaA10$_{3}$ (T1-2201), either in bulk or as an epitaxial thin film. It was observed that the superconductors exhibit a metal deficiency near the surface, which is largely compensated by excess oxygen. Moreover, the samples are significantly contaminated with carbon within the probing region of the H$^+$ beam. The thermal stability and surface degradation were studied in both oxidizing ambient and vacuum. As a general trend, the heavy metal deficiency — and consequently the compensating o...

  10. Spectra of Particulate Backscattering in Natural Waters

    Science.gov (United States)

    Gordon, Howard, R.; Lewis, Marlon R.; McLean, Scott D.; Twardowski, Michael S.; Freeman, Scott A.; Voss, Kenneth J.; Boynton, Chris G.

    2009-01-01

    Hyperspectral profiles of downwelling irradiance and upwelling radiance in natural waters (oligotrophic and mesotrophic) are combined with inverse radiative transfer to obtain high resolution spectra of the absorption coefficient (a) and the backscattering coefficient (bb) of the water and its constituents. The absorption coefficient at the mesotrophic station clearly shows spectral absorption features attributable to several phytoplankton pigments (Chlorophyll a, b, c, and Carotenoids). The backscattering shows only weak spectral features and can be well represented by a power-law variation with wavelength (lambda): b(sub b) approx. Lambda(sup -n), where n is a constant between 0.4 and 1.0. However, the weak spectral features in b(sub b), suggest that it is depressed in spectral regions of strong particle absorption. The applicability of the present inverse radiative transfer algorithm, which omits the influence of Raman scattering, is limited to lambda < 490 nm in oligotrophic waters and lambda < 575 nm in mesotrophic waters.

  11. Variations in Optical Scattering and Backscattering by Organic and Inorganic Particulates in Chinese Lakes of Taihu, Chaohu and Dianchi

    Institute of Scientific and Technical Information of China (English)

    LYU Heng; WANG Qiao; WU Chuanqing; ZHU Li; LI Yunmei; HUANG Jiazhu

    2015-01-01

    This stu dy presents an investigation of the scattering and backscattering properties of the particulates in three Chinese inlandlakes (the Taihu Lake,the Chaohu Lake and the Dianchi Lake) based on in situ measurements taken at 119 sites.We modeled the particulate scattering spectra using a wavelength-dependent power-law function,finding that the power-law exponents in the Taihu Lake and the Chaohu Lake differ from those in the Dianchi Lake but are similar to the values in the U.S.coastal waters.In contrast to the open ocean,the backscattering properties in the three lakes can not be determined only from chlorophyll-a concentration.The backscattering ratio spectra exhibit a wavelength dependence feature in all three lakes,generally decreasing with the increasing wavelength.Analysis results of the correlations between the backscattering ratio and the individual water quality parameters clearly show that there are distinctive relations among the three lakes,attributed primarily to different compositions of optically active materials in the three lakes.Analysis of the mass-specific scattering and backscattering coefficients shows that the coefficients at wavelength 532 nm in the Taihu Lake and Chaohu Lake are similar,but they are apparently different from those in the Dianehi Lake.Lastly,Model I multiple linear regressions were adopted to partition the mass-specific cross-sections for scattering and backscattering into organic and inorganic cross-sections to further interpret the scattering and backscattering properties.The relative contribution of organic and inorganic particulates to scattering and backscattering is clearly different among the three lakes.The scattering and backscattering properties of the particulates in the three inland lakes vary significantly based on our collected data.The results indicated that the existing semi-analytical water quality retrieval models of the Taihu Lake can not be applied perfectly to the Chaohu Lake and the Dianchi Lake.

  12. Concentration measurement of yeast suspensions using high frequency ultrasound backscattering.

    Science.gov (United States)

    Elvira, Luis; Vera, Pedro; Cañadas, Francisco Jesús; Shukla, Shiva Kant; Montero, Francisco

    2016-01-01

    This work proposes the use of an ultrasound based technique to measure the concentration of yeasts in liquid suspension. This measurement was achieved by the detection and quantification of ultrasonic echoes backscattered by the cells. More specifically, the technique was applied to the detection and quantification of Saccharomyces cerevisiae. A theoretical approach was proposed to get the average density and sound speed of the yeasts, which were found to be 1116 kg/m(3) and 1679 m/s, respectively. These parameters were needed to model the waves backscattered by each single cell. A pulse-echo arrangement working around 50 MHz, being able to detect echoes from single yeasts was used to characterize experimentally yeast solutions from 10(2) to 10(7)cells/ml. The Non-negative Matrix Factorization denoising technique was applied for data analysis. This technique required a previous learning of the spectral patterns of the echoes reflected from yeasts in solution and the base noise from the liquid medium. Comparison between pulse correlation (without denoising) and theoretical and experimental pattern learning was made to select the best signal processing. A linear relation between ultrasound output and concentration was obtained with correlation coefficient R(2)=0.996 for the experimental learning. Concentrations from 10(4) to 10(7)cells/ml were detected above the base noise. These results show the viability of using the ultrasound backscattering technique to detect yeasts and measure their concentration in liquid cultures, improving the sensitivity obtained using spectrophotometric methods by one order of magnitude.

  13. Radar Backscatter Study of Sea Ice.

    Science.gov (United States)

    1980-02-01

    in controlling the "state" of the ice ( temperatura and salinity) are shown in Figure 4.3-79. The salinity profile is a typical irregular c-shaped...the University of Kansas to provide well- controlled systematic studies to relate radar backscatter return to sea ice and to pin down some of the...34..,. : . - " ... ,. -.. .... .. .. ... ,,, ... ... _ ., ’.. . . , 72. Profiles of the parameters most important in controlling the "state" of the ice (temperature and salinity

  14. Low-Frequency Electromagnetic Backscattering from Tunnels

    Energy Technology Data Exchange (ETDEWEB)

    Casey, K; Pao, H

    2007-01-16

    Low-frequency electromagnetic scattering from one or more tunnels in a lossy dielectric half-space is considered. The tunnel radii are assumed small compared to the wavelength of the electromagnetic field in the surrounding medium; a tunnel can thus be modeled as a thin scatterer, described by an equivalent impedance per unit length. We examine the normalized backscattering width for cases in which the air-ground interface is either smooth or rough.

  15. Nondestructive atomic compositional analysis of BeMgZnO quaternary alloys using ion beam analytical techniques

    Energy Technology Data Exchange (ETDEWEB)

    Zolnai, Z., E-mail: zolnai.zsolt@ttk.mta.hu [Research Centre for Natural Sciences, Institute of Technical Physics and Materials Science (MFA), Konkoly-Thege M. út 29-33, H-1121 Budapest (Hungary); Toporkov, M. [Department of Electrical and Computer Engineering, Virginia Commonwealth University, 601W Main St, Richmond, VA 23284 (United States); Volk, J. [Research Centre for Natural Sciences, Institute of Technical Physics and Materials Science (MFA), Konkoly-Thege M. út 29-33, H-1121 Budapest (Hungary); Department of Electrical and Computer Engineering, Virginia Commonwealth University, 601W Main St, Richmond, VA 23284 (United States); Demchenko, D.O. [Department of Physics, Virginia Commonwealth University, 701W. Grace St., Richmond, VA 23284 (United States); Okur, S. [Department of Electrical and Computer Engineering, Virginia Commonwealth University, 601W Main St, Richmond, VA 23284 (United States); Szabó, Z. [Research Centre for Natural Sciences, Institute of Technical Physics and Materials Science (MFA), Konkoly-Thege M. út 29-33, H-1121 Budapest (Hungary); Özgür, Ü.; Morkoç, H.; Avrutin, V. [Department of Electrical and Computer Engineering, Virginia Commonwealth University, 601W Main St, Richmond, VA 23284 (United States); Kótai, E. [Wigner Research Centre for Physics, Institute for Particle and Nuclear Physics, Konkoly-Thege M. út 29-33, H-1121 Budapest (Hungary)

    2015-02-01

    Highlights: • BeMgZnO thin layers were grown with plasma-assisted molecular beam epitaxy (MBE). • The Be contents were accurately measured with RBS and proton elastic backscattering. • The Tauc bandgap was measured from optical transmittance experiments. • The bandgap has been varied between 3.26 eV and 4.62 eV via the Be and Mg content. • Experimental and density functional theory calculated bandgaps were in good agreement. - Abstract: The atomic composition with less than 1–2 atom% uncertainty was measured in ternary BeZnO and quaternary BeMgZnO alloys using a combination of nondestructive Rutherford backscattering spectrometry with 1 MeV He{sup +} analyzing ion beam and non-Rutherford elastic backscattering experiments with 2.53 MeV energy protons. An enhancement factor of 60 in the cross-section of Be for protons has been achieved to monitor Be atomic concentrations. Usually the quantitative analysis of BeZnO and BeMgZnO systems is challenging due to difficulties with appropriate experimental tools for the detection of the light Be element with satisfactory accuracy. As it is shown, our applied ion beam technique, supported with the detailed simulation of ion stopping, backscattering, and detection processes allows of quantitative depth profiling and compositional analysis of wurtzite BeZnO/ZnO/sapphire and BeMgZnO/ZnO/sapphire layer structures with low uncertainty for both Be and Mg. In addition, the excitonic bandgaps of the layers were deduced from optical transmittance measurements. To augment the measured compositions and bandgaps of BeO and MgO co-alloyed ZnO layers, hybrid density functional bandgap calculations were performed with varying the Be and Mg contents. The theoretical vs. experimental bandgaps show linear correlation in the entire bandgap range studied from 3.26 eV to 4.62 eV. The analytical method employed should help facilitate bandgap engineering for potential applications, such as solar blind UV photodetectors and

  16. Calculations of Backscattering Mueller Matrices for Turbid Media with a Sphere Queue Model

    Institute of Scientific and Technical Information of China (English)

    WANG Qing-Hua; LI Zhen-Hua; LAI Jian-Cheng; ZHANG Ying-Ying; HE An-Zhi

    2006-01-01

    A sphere queue model is introduced to calculate Mueller matrices of turbid media. Combined with the single scattering approximation, the backscattering Mueller matrices of turbid media can be computed rapidly by Mie theory. The numerical results agree with the azimuthal dependences of backscattering Mueller matrices' patterns from turbid media, which indicates that the major contribution to the Mueller matrices' patterns comes from the single scattering of the sphere queue, and the multiple scattering considered as a high-order correction does not change the patterns. The numerical analysis reveals that the contrast of Mueller matrices' patterns will decrease with increase of the concentration of media and the distance from the incident point.

  17. Inversion of dielectric constant and moisture of bare soil surface from backscattering coefficient

    Institute of Scientific and Technical Information of China (English)

    李宗谦; 冯孔豫

    1997-01-01

    An inverse method of dielectric constant and moisture of bare wet soil surface from backscattering coefficients is presented, which is based upon the small perturbation model of electromagnetic wave scattering from rough surfaces and the empirical and dielectric mixing models of wet soil. Some sets of curves which describe the relation between the moisture of soil and the ratio of like polarization backscattering coefficients σvv and σhh are obtained, and some principles on how to choose the incident frequencies and the incident angles of the electromagnetic wave are given Analysis and calculation show that the mam advantage of this inverse method is its efficiency and simplicity.

  18. Three-dimensional imaging of hidden objects using positron emission backscatter

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dongwon [Los Alamos National Laboratory; Cowee, Misa [Los Alamos National Laboratory; Fenimore, Ed [Los Alamos National Laboratory; Galassi, Mark [Los Alamos National Laboratory; Looker, Quinn [Los Alamos National Laboratory; Mcneil, Wendy V [Los Alamos National Laboratory; Stonehill, Laura [Los Alamos National Laboratory; Wallace, Mark [Los Alamos National Laboratory

    2009-01-01

    Positron emission backscatter imaging is a technique for interrogation and three-dimensional (3-D) reconstruction of hidden objects when we only have access to the objects from one side. Using time-of-flight differences in detected direct and backscattered positron-emitted photons, we construct 3-D images of target objects. Recently at Los Alamos National Laboratory, a fully three-dimensional imaging system has been built and the experimental results are discussed in this paper. Quantitative analysis of images reconstructed in both two- and three-dimensions are also presented.

  19. An Ultrasonic Backscatter Instrument for Cancellous Bone Evaluation in Neonates

    Directory of Open Access Journals (Sweden)

    Chengcheng Liu

    2015-09-01

    Full Text Available Ultrasonic backscatter technique has shown promise as a noninvasive cancellous bone assessment tool. A novel ultrasonic backscatter bone diagnostic (UBBD instrument and an in vivo application for neonatal bone evaluation are introduced in this study. The UBBD provides several advantages, including noninvasiveness, non-ionizing radiation, portability, and simplicity. In this study, the backscatter signal could be measured within 5 s using the UBBD. Ultrasonic backscatter measurements were performed on 467 neonates (268 males and 199 females at the left calcaneus. The backscatter signal was measured at a central frequency of 3.5 MHz. The delay (T1 and duration (T2 of the backscatter signal of interest (SOI were varied, and the apparent integrated backscatter (AIB, frequency slope of apparent backscatter (FSAB, zero frequency intercept of apparent backscatter (FIAB, and spectral centroid shift (SCS were calculated. The results showed that the SOI selection had a direct influence on cancellous bone evaluation. The AIB and FIAB were positively correlated with the gestational age (|R| up to 0.45, P10 µs. Moderate positive correlations (|R| up to 0.45, P10 µs. The T2 mainly introduced fluctuations in the observed correlation coefficients. The moderate correlations observed with UBBD demonstrate the feasibility of using the backscatter signal to evaluate neonatal bone status. This study also proposes an explicit standard for in vivo SOI selection and neonatal cancellous bone assessment.

  20. Discriminant classification of different fish-species backscattering

    Science.gov (United States)

    Zhang, Qiao; Xu, Feng; Liu, Yin; Zhang, Chun

    2012-11-01

    The complex structure of fish and multispecies composition complicate the analysis of acoustic data. Consequently, it is difficult to obtain a highly accurate rate of classification by using current approaches. This paper introduces two discriminating methods: the adaptive segmentation temporal centroid method and the wavelet packet multi-scale information entropy method. To verify and compare these two methods, an ex situ experiment has been performed with three kinds of fish: Crucian carp (Carassius auratus), Yellow-headed catfish (Pelteobagrus fulvidraco) and Bluntnose black bream (Megalobrama amblycephale). The backscattering signals of these fishes are obtained. Then the temporal centroid in the divided sub-segmentation of the backscattering envelope is calculated, and the multi-scale information entropy of the wavelet packet decomposition in different frequency bands is extracted. Finally, three kinds of fish are successfully classified by using a BP neural network. The result shows that the adaptive segmentation temporal centroid method is 4% more accurate than the wavelet packet multi-scale information entropy method.

  1. Subgrid-scale backscatter after the shock-turbulence interaction

    Science.gov (United States)

    Livescu, Daniel; Li, Zhaorui

    2017-01-01

    The statistics of the subgrid scales (SGS) are studied in the context of Large Eddy Simulations (LES) of turbulence after the interaction with a nominally normal shock wave. In general, in practical applications, the shock wave width is much smaller than the turbulence scales and the upstream turbulent Mach number is modest. In this case, recent high resolution shock-resolved Direct Numerical Simulations (DNS) (Ryu and Livescu, J. Fluid Mech., 756, R1, 2014) show that the interaction can be described by the Linear Interaction Approximation (LIA). By using LIA to alleviate the need to resolve the shock wave, DNS post-shock data can be generated at much higher Reynolds numbers than previously possible. Here, such results with Taylor Reynolds number ≈ 180 are used for an analysis of the SGS backscatter properties. In particular, it is shown that the interaction with the shock wave decreases the asymmetry of the SGS dissipation Probability Density Function (PDF) as the shock Mach number increases, with a significant enhancement in size of the regions and magnitude of backscatter.

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

    DEFF Research Database (Denmark)

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

    2013-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2000-01-01

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

  4. Backscattering Differential Ghost Imaging in Turbid Media

    CERN Document Server

    Bina, M; Molteni, M; Gatti, A; Lugiato, L A; Ferri, F

    2012-01-01

    In this Letter we present experimental results concerning the retrieval of images of absorbing objects immersed in turbid media via differential ghost imaging (DGI) in a backscattering configuration. The method has been applied, for the first time to our knowledge, to the imaging of small thin black objects located at different depths inside a turbid solution of polystyrene nanospheres and its performances assessed via comparison with standard imaging techniques. A simple theoretical model capable of describing the basic optics of DGI in turbid media is proposed.

  5. Simulation of ultrasound backscatter images from fish

    DEFF Research Database (Denmark)

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

    2011-01-01

    The objective of this work is to investigate ultrasound (US) backscatter in the MHz range from fis to develop a realistic and reliable simulation model. The long term objective of the work is to develop the needed signal processing for fis species differentiation using US. In in-vitro experiments...... is 10 MHz and the Full Width at Half Maximum (FWHM) at the focus point is 0.54 mm in the lateral direction. The transducer model in Field II was calibrated using a wire phantom to validate the simulated point spread function. The inputs to the simulation were the CT image data of the fis converted...

  6. Laser remote sensing of tropospheric aerosol over Southern Ireland using a backscatter Raman LIDAR

    Science.gov (United States)

    Ruth, Albert A.; Acheson, Karen; Apituley, Arnoud; Chaikovsky, Anatoli; Nicolae, Doina; Ortiz-Amezcua, Pablo; Stoyanov, Dimitar; Trickl, Thomas

    2016-04-01

    Raman backscatter coefficients, extinction coefficients and lidar ratios were measured with a ground based Raman lidar system at University College Cork, Ireland, during the periods of July 2012 - August 2012, April 2013 - December 2013 and March 2014 - May 2014. Statistical analysis of these parameters in this time provided information about seasonal effects of Raman backscatter coefficients and the altitude of the top of the planetary boundary layer. The mean of the altitude of the top of the planetary boundary layer over these time periods is 950 ± 302 m. The values are larger in summer, 1206 ± 367 m, than in winter, 735 m. The altitude of the top of the planetary boundary layer measured at Cork is lower than most EARLINET stations. Raman backscatter coefficients above and altitude of 2 km are highest in summer and spring where the values are greater than 0.28 Mm-1 sr-1. Winter values of Raman backscatter coefficient are less than 0.06 Mm-1 sr-1. These seasonal effects are consistent with most EARLINET stations. Large aerosol loads were detected in July 2013 due to a Canadian forest fire event. HYSPLIT air-mass back trajectory models were used to trace the origin of the detected aerosol layers. The aerosol forecast model, MACC, was used to further investigate and verify the propagation of the smoke. The Lidar ratio values and Klett and Raman backscatter coefficients at Cork, for the 4th July, the 7th to 9th of July and the 11th July were compared with observations at Cabauw, Minsk, Granada, Bucharest, Sofia and Garmisch. Lidar ratio values for the smoke detected at Cork were determined to be between 33 sr and 62 sr. The poster will discuss the seasonal changes of Raman backscatter coefficients and the altitude of the top of the planetary boundary layer at Cork. An investigation of a Canadian forest fire event measured at Cork will be compared with other data from the EARLINET database.

  7. Demonstration of zero optical backscattering from single nanoparticles

    CERN Document Server

    Person, Steven; Lapin, Zachary; Saenz, Juan Jose; Wicks, Gary; Novotny, Lukas

    2012-01-01

    We present the first experimental demonstration of zero backscattering from nanoparticles at op- tical frequencies as originally discussed by Kerker et. al. [M. Kerker, D. Wang, and C. Giles, J. Opt. Soc. A 73, 765 (1983)]. GaAs pillars were fabricated on a fused silica substrate and the spectrum of the backscattered radiation was measured in the wavelength range 600-1000 nm. Suppression of backscattering occurred at ~725 nm, agreeing with calculations based on the discrete dipole approximation. Particles with zero backscattering provide new functionality for metamaterials and optical antennas.

  8. CRED Acoustic Backscatter Guam 2003, Imagery Extracted from Gridded Bathymetry

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Backscatter extracted from gridded bathymetry of the banktops and shelf environments of Guam, of the Mariana Islands Archipelago.

  9. Sea Floor Analyses Based On Multibeam Backscatter Strength

    Science.gov (United States)

    Beyer, A.

    Measurements of acoustic backscatter strength can be applied to analyse sea floor coverage on a spatial extent. They provide consistent coverage compared to analy- ses based on only a few surface samples. In particular the spatial validity of surface samples can be determined by analyses based on acoustic backscatter strength and sampling locations representative for the surrounding area can be determined. Dur- ing the cruise ANTXVII/4 of the German RV "Polarstern", a high precision swath bathymetry survey was performed along the European continental margin in the Por- cupine Seabight off southwest Ireland. Within the Porcupine Seabight a number of mound structures have been discovered earlier, most of them being carbonate mounds. The structure and genesis of these mounds are the main objective of recent investiga- tions. The cruise and the subsequent investigations are part of the EU project GEO- MOUND. They focus on the Belgica mound province. Besides the depth measure- ments, the acoustic intensities of the received echos have been recorded. Taking into account the transmitted and received sound level, acoustic beam patterns, and acous- tic attenuation in the water column, the backscatter strength of the ensonified area was calculated. This backscatter information is used to analyse the sea floor cover- age. Based on the data of the systematic survey the spatial variation of the backscatter strength was derived. Regions of equal backscatter characteristic can be combined and functions showing the dependency between backscatter strength and incidence angle of the acoustic wave can be determined. These functions help interpreting sea floor coverage. The mapping of the backscatter strength of the mound area indicates clear changes in backscatter strength. Small and shallow channels show a lower backscat- ter strength than their surroundings. That means the surface coverage of the channels is smooth with respect to the surroundings. One interpretation of this

  10. The aCORN backscatter-suppressed beta spectrometer

    Science.gov (United States)

    Hassan, M. T.; Bateman, F.; Collett, B.; Darius, G.; DeAngelis, C.; Dewey, M. S.; Jones, G. L.; Komives, A.; Laptev, A.; Mendenhall, M. P.; Nico, J. S.; Noid, G.; Stephenson, E. J.; Stern, I.; Trull, C.; Wietfeldt, F. E.

    2017-09-01

    Backscatter of electrons from a beta detector, with incomplete energy deposition, can lead to undesirable effects in many types of experiments. We present and discuss the design and operation of a backscatter-suppressed beta spectrometer that was developed as part of a program to measure the electron-antineutrino correlation coefficient in neutron beta decay (aCORN). An array of backscatter veto detectors surrounds a plastic scintillator beta energy detector. The spectrometer contains an axial magnetic field gradient, so electrons are efficiently admitted but have a low probability for escaping back through the entrance after backscattering. The design, construction, calibration, and performance of the spectrometer are discussed.

  11. Radar backscatter properties of milo and soybeans

    Science.gov (United States)

    Bush, T. F.; Ulaby, F. T.; Metzler, T.

    1975-01-01

    The radar backscatter from fields of milo and soybeans was measured with a ground based radar as a function of frequency (8-18 GHz), polarization (HH and VV) and angle of incidence (0 deg-70 deg) during the summer of 1974. Supporting ground truth was gathered contemporaneously with the backscatter data. At nadir sigma deg of milo correlated highly, r = 0.96, with soil moisture in the milo field at 8.6 GHz but decreased to a value of r = 0.78 at a frequency of 17.0 GHz. Correlation studies of the variations of sigma deg with soil moisture in the soybean fields were not possible due to a lack of a meaningful soil moisture dynamic range. At the larger angles of incidence, however, sigma deg of soybeans did appear to be dependent on precipitation. It is suggested this phenomenon was caused by the rain altering plant geometry. In general sigma deg of both milo and soybeans had a relatively small dynamic range at the higher angles of incidence and showed no significant dependence on the measured crop parameters.

  12. 卢瑟福公式中正负号问题的探讨%Discussion on Positive an d Negative Signs in Rutherford Formula

    Institute of Scientific and Technical Information of China (English)

    尹海峰; 曾春花

    2014-01-01

    分析了某些理论力学教材在推导卢瑟福公式过程中,处理正负号问题不完善的地方,并给出了一种新的推导方式,从而达到对卢瑟福公式全面完整的认识。%By analyzing imperfections of some teaching materials in calculating Rutherford formula ,this paper gives a new derivation mode ,and provides a full and complete comprehension on Rutherford formula .

  13. Remote identification of a shipwreck site from MBES backscatter.

    Science.gov (United States)

    Masetti, Giuseppe; Calder, Brian

    2012-11-30

    The method described attempts to remotely identify the shape of an anthropogenic object, such as a wreck of a modern vessel, using reflectivity data from Multi-Beam Echosounder (MBES) systems. In the beam domain, the backscatter strength values - geometrically and radiometrically corrected - are used to extract a large number of Gray Level Co-occurrence Matrix (GLCM) features with different input parameters. Principal Component Analysis (PCA) is applied in order to achieve dimensionality reduction whilst a K-means algorithm clusters as "shipwreck site" a large number of beams for each line. After the geo-referencing process, a K-nearest-neighbors (K-NN) technique is applied as a filter for possible misclassifications. Finally, the shape of the shipwreck site is defined from the georeferenced beams using the α-shape method, constructing an output compatible with Geographic Information Systems (GIS).

  14. Diffuse Backscattering Mueller Matrices Patterns from Turbid Media

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lian-Shun; ZHU Chen; WANG Zhi-Ping; ZHANG Jing

    2006-01-01

    We present experimental measurements and theory of the diffusely backscattered Mueller matrix patterns that arise from illuminating a turbid medium with a polarized laser beam. Our technique employs polarized light from a He-Ne laser (λ= 632.8 nm) focused onto the surface of the scattering medium. A surface area of approximately 2×2 cm2 centred on the light input point is imaged through polarization analysis optics onto a CCD camera. The Mueller matrix is reconstructed by 49 intensity measurements with various orientations of polarizer and analyser. The measured Mueller matrix of polystyrene spheres is compared with the theory result of incoherent scattering of light by spheres. It shows that the azimuthal patterns of the Mueller matrix are determined by the symmetry of the turbid media and the shape of scattering particles. The result is further proved by experiments with polystyrene spheres of different concentrations in de-ionized water.

  15. Ray-based calculations of laser backscatter in ICF targets

    CERN Document Server

    Strozzi, D J; Hinkel, D E; Froula, D H; London, R A; Callahan, D A

    2008-01-01

    A steady-state model for Brillouin and Raman backscatter along a laser ray path is presented. The daughter plasma waves are treated in the strong damping limit, and have amplitudes given by the (linear) kinetic response to the ponderomotive drive. Pump depletion, inverse-bremsstrahlung damping, bremsstrahlung emission, Thomson scattering off density fluctuations, and whole-beam focusing are included. The numerical code Deplete, which implements this model, is described. The model is compared with traditional linear gain calculations, as well as ``plane-wave'' simulations with the paraxial propagation code pF3D. Comparisons with Brillouin-scattering experiments at the Omega Laser Facility show that laser speckles greatly enhance the reflectivity over the Deplete results. An approximate upper bound on this enhancement is given by doubling the Deplete coupling coefficient. Analysis with Deplete of an ignition design for the National Ignition Facility (NIF), with a peak radiation temperature of 285 eV, shows enco...

  16. First beam measurements on the vessel for extraction and source plasma analyses (VESPA) at the Rutherford Appleton Laboratory (RAL)

    Energy Technology Data Exchange (ETDEWEB)

    Lawrie, Scott R., E-mail: scott.lawrie@stfc.ac.uk [ISIS Neutron and Muon Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, OX11 0QX (United Kingdom); John Adams Institute for Accelerator Science, Department of Physics, University of Oxford (United Kingdom); Faircloth, Daniel C.; Letchford, Alan P.; Perkins, Mike; Whitehead, Mark O.; Wood, Trevor [ISIS Neutron and Muon Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, OX11 0QX (United Kingdom)

    2015-04-08

    In order to facilitate the testing of advanced H{sup −} ion sources for the ISIS and Front End Test Stand (FETS) facilities at the Rutherford Appleton Laboratory (RAL), a Vessel for Extraction and Source Plasma Analyses (VESPA) has been constructed. This will perform the first detailed plasma measurements on the ISIS Penning-type H{sup −} ion source using emission spectroscopic techniques. In addition, the 30-year-old extraction optics are re-designed from the ground up in order to fully transport the beam. Using multiple beam and plasma diagnostics devices, the ultimate aim is improve H{sup −} production efficiency and subsequent transport for either long-term ISIS user operations or high power FETS requirements. The VESPA will also accommodate and test a new scaled-up Penning H{sup −} source design. This paper details the VESPA design, construction and commissioning, as well as initial beam and spectroscopy results.

  17. Coherent Backscattering of Ultra-cold Atoms

    CERN Document Server

    Jendrzejewski, Fred; Richard, Jérémie; Date, Aditya; Plisson, Thomas; Bouyer, Philippe; Aspect, Alain; Josse, Vincent

    2012-01-01

    We report on the direct observation of coherent backscattering (CBS) of ultra-cold atoms, in a quasi two dimensional configuration. Launching atoms with a well defined momentum in a laser speckle disordered potential, we follow the progressive build up of the momentum scattering pattern, consisting of a ring associated with multiple elastic scattering, and the CBS peak in the backward direction. Monitoring the depletion of the initial momentum component and the formation of the angular ring profile allow us to determine microscopic transport quantities. The time resolved evolution of the CBS peak is studied and is found a fair agreement with predictions, at long times as well as at short times. The observation of CBS can be considered a direct signature of coherence in quantum transport of particles in disordered media. It is responsible for the so called weak localization phenomenon, which is the precursor of Anderson localization.

  18. Electron Backscatter Diffraction in Low Vacuum Conditions

    Energy Technology Data Exchange (ETDEWEB)

    El-Dasher, B S; Torres, S G

    2008-07-17

    Most current scanning electron microscopes (SEMs) have the ability to analyze samples in a low vacuum mode, whereby a partial pressure of water vapor is introduced into the SEM chamber, allowing the characterization of nonconductive samples without any special preparation. Although the presence of water vapor in the chamber degrades electron backscatter diffraction (EBSD) patterns, the potential of this setup for EBSD characterization of nonconductive samples is immense. In this chapter we discuss the requirements, advantages and limitations of low vacuum EBSD (LV-EBSD), and present how this technique can be applied to a two-phase ceramic composite as well as hydrated biominerals as specific examples of when LV-EBSD can be invaluable.

  19. Electron backscatter diffraction in materials characterization

    Directory of Open Access Journals (Sweden)

    Dejan Stojakovic

    2012-03-01

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

  20. Characterization of highly scattering media by measurement of diffusely backscattered polarized light

    Energy Technology Data Exchange (ETDEWEB)

    Hielscher, A.H.; Mourant, J.R.; Bigio, I.J.

    2000-01-04

    An apparatus and method for recording spatially dependent intensity patterns of polarized light that is diffusely backscattered from highly scattering media are described. These intensity patterns can be used to differentiate different turbid media, such as polystyrene-sphere and biological-cell suspensions. Polarized light from a He-Ne laser ({lambda} = 543 nm) is focused onto the surface of the scattering medium, and a surface area of approximately 4 x 4 cm centered on the light input point is imaged through polarization analysis optics onto a CCD camera. A variety of intensity patterns may be observed by varying the polarization state of the incident laser light and changing the analyzer configuration to detect different polarization components of the backscattered light. Experimental results for polystyrene-sphere and intralipid suspensions demonstrate that the radial and azimuthal variations of the observed pattern depend on the concentration, size, and anisotropy factor, g, of the particles constituting the scattering medium. Measurements performed on biological cell suspensions show that intensity patterns can be used to differentiate between suspensions of cancerous and non-cancerous cells. Introduction of the Mueller-matrix for diffusely backscattered light, permits the selection of a subset of measurements which comprehensively describes the optical properties of backscattering media.

  1. Characterization of highly scattering media by measurement of diffusely backscattered polarized light

    Energy Technology Data Exchange (ETDEWEB)

    Hielscher, Andreas H. (Brooklyn, NY); Mourant, Judith R. (Los Alamos, NM); Bigio, Irving J. (Los Alamos, NM)

    2000-01-01

    An apparatus and method for recording spatially dependent intensity patterns of polarized light that is diffusely backscattered from highly scattering media are described. These intensity patterns can be used to differentiate different turbid media, such as polystyrene-sphere and biological-cell suspensions. Polarized light from a He-Ne laser (.lambda.=543 nm) is focused onto the surface of the scattering medium, and a surface area of approximately 4.times.4 cm centered on the light input point is imaged through polarization analysis optics onto a CCD camera. A variety of intensity patterns may be observed by varying the polarization state of the incident laser light and changing the analyzer configuration to detect different polarization components of the backscattered light. Experimental results for polystyrene-sphere and Intralipid suspensions demonstrate that the radial and azimuthal variations of the observed pattern depend on the concentration, size, and anisotropy factor, g, of the particles constituting the scattering medium. Measurements performed on biological cell suspensions show that intensity patterns can be used to differentiate between suspensions of cancerous and non-cancerous cells. Introduction of the Mueller-matrix for diffusely backscattered light, permits the selection of a subset of measurements which comprehensively describes the optical properties of backscattering media.

  2. Multi-angle backscatter classification and sub-bottom profiling for improved seafloor characterization

    Science.gov (United States)

    Alevizos, Evangelos; Snellen, Mirjam; Simons, Dick; Siemes, Kerstin; Greinert, Jens

    2017-06-01

    This study applies three classification methods exploiting the angular dependence of acoustic seafloor backscatter along with high resolution sub-bottom profiling for seafloor sediment characterization in the Eckernförde Bay, Baltic Sea Germany. This area is well suited for acoustic backscatter studies due to its shallowness, its smooth bathymetry and the presence of a wide range of sediment types. Backscatter data were acquired using a Seabeam1180 (180 kHz) multibeam echosounder and sub-bottom profiler data were recorded using a SES-2000 parametric sonar transmitting 6 and 12 kHz. The high density of seafloor soundings allowed extracting backscatter layers for five beam angles over a large part of the surveyed area. A Bayesian probability method was employed for sediment classification based on the backscatter variability at a single incidence angle, whereas Maximum Likelihood Classification (MLC) and Principal Components Analysis (PCA) were applied to the multi-angle layers. The Bayesian approach was used for identifying the optimum number of acoustic classes because cluster validation is carried out prior to class assignment and class outputs are ordinal categorical values. The method is based on the principle that backscatter values from a single incidence angle express a normal distribution for a particular sediment type. The resulting Bayesian classes were well correlated to median grain sizes and the percentage of coarse material. The MLC method uses angular response information from five layers of training areas extracted from the Bayesian classification map. The subsequent PCA analysis is based on the transformation of these five layers into two principal components that comprise most of the data variability. These principal components were clustered in five classes after running an external cluster validation test. In general both methods MLC and PCA, separated the various sediment types effectively, showing good agreement (kappa >0.7) with the Bayesian

  3. Statistics of vertical backscatter profile of cirrus clouds

    Directory of Open Access Journals (Sweden)

    P. Veglio

    2011-09-01

    Full Text Available A nearly global statistical analysis of vertical backscatter and extinction profiles of cirrus clouds collected by the CALIOP lidar, on-board of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation, is presented.

    Statistics on frequency of occurrence and distributions of bulk properties of cirrus clouds in general and, for the first time, of horizontally homogeneous (on a 5-km field of view cirrus clouds only are provided. Annual and seasonal backscatter profiles (BSP are computed for the horizontally homogeneous cirri. Differences found in the day/night cases and for midlatitudes and tropics are studied in terms of the mean physical parameters of the clouds from which they are derived.

    The relation between cloud physical parameters (optical depth, geometrical thickness and temperature and the shape of the BSP is investigated. It is found that cloud geometrical thickness is the main parameter affecting the shape of the mean CALIOP BSP. Specifically, cirrus clouds with small geometrical thicknesses show a maximum in mean BSP curve placed near cloud top. As the cloud geometrical thickness increases the BSP maximum shifts towards cloud base. Cloud optical depth and temperature have smaller effect on the shape of the CALIOP BSPs. In general a slight increase in the BSP maximum is observed as cloud temperature and optical depth increase.

    In order to fit mean BSPs, as functions of geometrical thickness and position within the cloud layer, polynomial functions are provided. The impact on satellite radiative transfer simulations in the infrared spectrum when using either a constant ice-content (IWC along the cloud vertical dimension or an IWC profile derived from the BSP fitting functions is evaluated. It is, in fact, demonstrated that, under realistic hypotheses, the mean BSP is linearly proportional to the IWC profile.

  4. Statistics of vertical backscatter profiles of cirrus clouds

    Directory of Open Access Journals (Sweden)

    P. Veglio

    2011-12-01

    Full Text Available A nearly global statistical analysis of vertical backscatter and extinction profiles of cirrus clouds collected by the CALIOP lidar, on-board of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation, is presented.

    Statistics on frequency of occurrence and distribution of bulk properties of cirrus clouds in general and, for the first time, of horizontally homogeneous (on a 5-km field of view cirrus clouds only are provided. Annual and seasonal backscatter profiles (BSP are computed for the horizontally homogeneous cirri. Differences found in the day/night cases and for midlatitudes and tropics are studied in terms of the mean physical parameters of the clouds from which they are derived.

    The relationship between cloud physical parameters (optical depth, geometrical thickness and temperature and the shape of the BSP is investigated. It is found that cloud geometrical thickness is the main parameter affecting the shape of the mean CALIOP BSP. Specifically, cirrus clouds with small geometrical thicknesses show a maximum in mean BSP curve located near cloud top. As the cloud geometrical thickness increases the BSP maximum shifts towards cloud base. Cloud optical depth and temperature have smaller effects on the shape of the CALIOP BSPs. In general a slight increase in the BSP maximum is observed as cloud temperature and optical depth increase.

    In order to fit mean BSPs, as functions of geometrical thickness and position within the cloud layer, polynomial functions are provided. The impact on satellite radiative transfer simulations in the infrared spectrum when using either a constant ice-content (IWC along the cloud vertical dimension or an IWC profile derived from the BSP fitting functions is evaluated. It is, in fact, demonstrated that, under realistic hypotheses, the mean BSP is linearly proportional to the IWC profile.

  5. Monte Carlo simulations of backscattering process in dislocation-containing SrTiO{sub 3} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Jozwik, P., E-mail: przemyslaw.jozwik@itme.edu.pl [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warszawa (Poland); National Centre for Nuclear Research, Andrzeja Soltana 7, 05-400 Swierk/Otwock (Poland); Sathish, N. [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warszawa (Poland); Nowicki, L. [National Centre for Nuclear Research, Andrzeja Soltana 7, 05-400 Swierk/Otwock (Poland); Jagielski, J.; Turos, A. [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warszawa (Poland); National Centre for Nuclear Research, Andrzeja Soltana 7, 05-400 Swierk/Otwock (Poland); Kovarik, L.; Arey, B. [Pacific Northwest National Laboratory, Richland, WA 99352 (United States)

    2014-05-01

    Studies of defects formation in crystals are of obvious importance in electronics, nuclear engineering and other disciplines where materials are exposed to different forms of irradiation. Rutherford Backscattering/Channeling (RBS/C) and Monte Carlo (MC) simulations are the most convenient tool for this purpose, as they allow one to determine several features of lattice defects: their type, concentration and damage accumulation kinetic. On the other hand various irradiation conditions can be efficiently modeled by ion irradiation method without leading to the radioactivity of the sample. Combination of ion irradiation with channeling experiment and MC simulations appears thus as a most versatile method in studies of radiation damage in materials. The paper presents the results on such a study performed on SrTiO{sub 3} (STO) single crystals irradiated with 320 keV Ar ions. The samples were analyzed also by using HRTEM as a complementary method which enables the measurement of geometrical parameters of crystal lattice deformation in the vicinity of dislocations. Once the parameters and their variations within the distance of several lattice constants from the dislocation core are known, they may be used in MC simulations for the quantitative determination of dislocation depth distribution profiles. The final outcome of the deconvolution procedure are cross-sections values calculated for two types of defects observed (RDA and dislocations)

  6. Monte Carlo simulations of backscattering process in dislocation-containing SrTiO3 single crystal

    Science.gov (United States)

    Jozwik, P.; Sathish, N.; Nowicki, L.; Jagielski, J.; Turos, A.; Kovarik, L.; Arey, B.

    2014-05-01

    Studies of defects formation in crystals are of obvious importance in electronics, nuclear engineering and other disciplines where materials are exposed to different forms of irradiation. Rutherford Backscattering/Channeling (RBS/C) and Monte Carlo (MC) simulations are the most convenient tool for this purpose, as they allow one to determine several features of lattice defects: their type, concentration and damage accumulation kinetic. On the other hand various irradiation conditions can be efficiently modeled by ion irradiation method without leading to the radioactivity of the sample. Combination of ion irradiation with channeling experiment and MC simulations appears thus as a most versatile method in studies of radiation damage in materials. The paper presents the results on such a study performed on SrTiO3 (STO) single crystals irradiated with 320 keV Ar ions. The samples were analyzed also by using HRTEM as a complementary method which enables the measurement of geometrical parameters of crystal lattice deformation in the vicinity of dislocations. Once the parameters and their variations within the distance of several lattice constants from the dislocation core are known, they may be used in MC simulations for the quantitative determination of dislocation depth distribution profiles. The final outcome of the deconvolution procedure are cross-sections values calculated for two types of defects observed (RDA and dislocations).

  7. Lord Rutherford of Nelson, his 1908 Nobel Prize in Chemistry, and why he didn't get a second prize

    Energy Technology Data Exchange (ETDEWEB)

    Jarlskog, Cecilia [Division of Mathematical Physics, LTH, Lund University, Box 118, S-22100 Lund (Sweden)], E-mail: cecilia.jarlskog@matfys.lth.se

    2008-11-01

    'I have dealt with many different transformations with various periods of time, but the quickest that I have met was my own transformation in one moment from a physicist to a chemist.' Ernest Rutherford (Nobel Banquet, 1908) This article is about how Ernest Rutherford (1871-1937) got the 1908 Nobel Prize in Chemistry and why he did not get a second Prize for his subsequent outstanding discoveries in physics, specially the discovery of the atomic nucleus and the proton. Who were those who nominated him and who did he nominate for the Nobel Prizes? In order to put the Prize issue into its proper context, I will briefly describe Rutherford's whereabouts. Rutherford, an exceptionally gifted scientist who revolutionized chemistry and physics, was moulded in the finest classical tradition. What were his opinions on some scientific issues such as Einstein's photon, uncertainty relations and the future prospects for atomic energy? What would he have said about the 'Theory of Everything'? Extended version of an invited talk presented at the conference 'Neutrino 2008', Christchurch, NZ, 25-31 May 2008.

  8. Variations in daily quality assurance dosimetry from device levelling, feet position and backscatter material.

    Science.gov (United States)

    Ceylan, Abdurrahman; Butson, Martin; Cullen, Ashley; Yu, Peter K N; Alnawaf, Hani

    2012-12-01

    Daily quality assurance procedures are an essential part of radiotherapy medical physics. Devices such as the Sun Nuclear, DQA3 are effective tools for analysis of daily dosimetry including flatness, symmetry, energy, field size and central axis radiation dose measurement. The DQA3 can be used on the treatment couch of the linear accelerator or on a dedicated table/bed for superficial and orthovoltage x-ray machines. This device is levelled using its dedicated feet. This work has shown that depending on the quantity of backscatter material behind the DQA3 device, the position of the levelling feet can affect the measured central axis dose by up to 1.8 % (250 kVp and 6 MV) and that the introduction of more backscatter material behind the DQA3 can lead to up to 7.2 % (6 MV) variations in measured central axis dose. In conditions where no backscatter material is present, dose measurements can vary up to 1 %. As such this work has highlighted the need to keep the material behind the DQA3 device constant as well as maintaining the accuracy of the feet position on the device to effectively measure the most accurate daily constancy achievable. Results have also shown that variations in symmetry and energy calculations of up to 1 % can occur if the device is not levelled appropriately. As such, we recommend the position of the levelling feet on the device be as close as possible to the device so that a constant distance is kept between the DQA3 and the treatment couch and thus minimal levelling variations also occur. We would also recommend having no extra backscattering material behind the DQA3 device during use to minimise any variations which might occur from these backscattering effects.

  9. Large areas elemental mapping by ion beam analysis techniques

    Science.gov (United States)

    Silva, T. F.; Rodrigues, C. L.; Curado, J. F.; Allegro, P.; Moro, M. V.; Campos, P. H. O. V.; Santos, S. B.; Kajiya, E. A. M.; Rizzutto, M. A.; Added, N.; Tabacniks, M. H.

    2015-07-01

    The external beam line of the Laboratory for Material Analysis with Ion Beams (LAMFI) is a versatile setup for multi-technique analysis. X-ray detectors for Particle Induced X-rays Emission (PIXE) measurements, a Gamma-ray detector for Particle Induced Gamma- ray Emission (PIGE), and a particle detector for scattering analysis, such as Rutherford Backscattering Spectrometry (RBS), were already installed. In this work, we present some results, using a large (60-cm range) XYZ computer controlled sample positioning system, completely developed and build in our laboratory. The XYZ stage was installed at the external beam line and its high spacial resolution (better than 5 μm over the full range) enables positioning the sample with high accuracy and high reproducibility. The combination of a sub-millimeter beam with the large range XYZ robotic stage is being used to produce elemental maps of large areas in samples like paintings, ceramics, stones, fossils, and all sort of samples. Due to its particular characteristics, this is a unique device in the sense of multi-technique analysis of large areas. With the continuous development of the external beam line at LAMFI, coupled to the robotic XYZ stage, it is becoming a robust and reliable option for regular analysis of trace elements (Z > 5) competing with the traditional in-vacuum ion-beam-analysis with the advantage of automatic rastering.

  10. Ion-Beam Analysis of Airborne Pollution

    Science.gov (United States)

    Harrington, Charles; Gleason, Colin; Schuff, Katie; Battaglia, Maria; Moore, Robert; Turley, Colin; Labrake, Scott; Vineyard, Michael

    2010-11-01

    An undergraduate laboratory research program in ion-beam analysis (IBA) of atmospheric aerosols is being developed to study pollution in the Capitol District and Adirondack Mountains of New York. The IBA techniques applied in this project include proton induced X-ray emission (PIXE), proton induced gamma-ray emission (PIGE), Rutherford backscattering (RBS), and proton elastic scattering analysis (PESA). These methods are well suited for studying air pollution because they are quick, non-destructive, require little to no sample preparation, and capable of investigating microscopic samples. While PIXE spectrometry is used to analyze most elements from silicon to uranium, the other techniques are being applied to measure some of the remaining elements and complement PIXE in the study of aerosols. The airborne particulate matter is collected using nine-stage cascade impactors that separate the particles according to size and the samples are bombarded with proton beams from the Union College 1.1-MV Pelletron Accelerator. The reaction products are measured with SDD X-ray, Ge gamma-ray, and Si surface barrier charged particle detectors. Here we report on the progress we have made on the PIGE, RBS, and PESA analysis of aerosol samples.

  11. X-ray backscatter imaging of nuclear materials

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-09-30

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

  12. Portable fluorescence meter with reference backscattering channel

    Science.gov (United States)

    Kornilin, Dmitriy V.; Grishanov, Vladimir N.; Zakharov, Valery P.; Burkov, Dmitriy S.

    2016-09-01

    Methods based on fluorescence and backscattering are intensively used for determination of the advanced glycation end products (AGE) concentration in the biological tissues. There are strong correlation between the AGE concentration and the severity of such diseases like diabetes, coronary heart disease and renal failure. This fact can be used for diagnostic purposes in medical applications. Only few investigations in this area can be useful for development of portable and affordable in vivo AGE meter because the most of them are oriented on using spectrometers. In this study we describe the design and the results of tests on volunteers of portable fluorescence meter based on two photodiodes. One channel of such fluorimeter is used for measurement of the autofluorescence (AF) intensity, another one - for the intensity of elastically scattered radiation, which can be used as a reference. This reference channel is proposed for normalization of the skin autofluorescence signal to the human skin photo type. The fluorimeter, that was developed is relatively compact and does not contain any expensive optical and electronic components. The experimental results prove that proposed tool can be used for the AGE estimation in human skin.

  13. Aerosol measurement program strategy for global aerosol backscatter model development

    Science.gov (United States)

    Bowdle, David A.

    1985-01-01

    The purpose was to propose a balanced program of aerosol backscatter research leading to the development of a global model of aerosol backscatter. Such a model is needed for feasibility studies and systems simulation studies for NASA's prospective satellite-based Doppler lidar wind measurement system. Systems of this kind measure the Doppler shift in the backscatter return from small atmospheric aerosol wind tracers (of order 1 micrometer diameter). The accuracy of the derived local wind estimates and the degree of global wind coverage for such a system are limited by the local availability and by the global scale distribution of natural aerosol particles. The discussions here refer primarily to backscatter model requirements at CO2 wavelengths, which have been selected for most of the Doppler lidar systems studies to date. Model requirements for other potential wavelengths would be similar.

  14. Backscatter B [USGS]--Offshore of Santa Barbara, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3281 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3281) of the Offshore of Santa Barbara map area, California. The...

  15. Backscatter B [USGS]--Offshore of Ventura, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3254 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3254) of the Offshore Ventura map area, California. The raster data...

  16. Backscatter [7125]-- Offshore of Monterey Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents 2-m-resolution Reson 7125 data for the acoustic-backscatter map of Offshore of Monterey map area, California. These metadata describe...

  17. Backscatter [Swath]-- Offshore of Monterey Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents 2-m-resolution SWATHPlus data for the acoustic-backscatter map of Offshore of Monterey map area, California. These metadata describe...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-11-30

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

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

    Digital Repository Service at National Institute of Oceanography (India)

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

    Algorithms to determine the inherent optical properties of water, backscattering probability and single scattering albedo at 490 and 676 nm from the apparent optical property, remote sensing reflectance are presented here. The measured scattering...

  20. Reson 8101 Backscatter imagery of Penguin Bank, Molokai, Hawaii, USA

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Backscatter imagery extracted from gridded bathymetry of Penguin Bank, Molokai, Hawaii, USA. These data provide almost complete coverage between 0 and 100 meters....

  1. Bathymetry and Acoustic Backscatter: Northern Santa Barbara Channel, Southern California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This report presents bathymetry and acoustic backscatter data collected in July 2008 in the northern Santa Barbara Channel, California, using a bathymetric sidescan...

  2. Backscatter [8101]--Offshore of Monterey Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents 2-m-resolution Reson 8101 data for the acoustic-backscatter map of the Offshore of Monterey map area, California. These metadata...

  3. LIDAR for atmospheric backscatter and temperature measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objectives of this effort are to measure atmospheric backscatter profiles and temperature using a zenith looking lidar, designed for a small lander.The lidar...

  4. Backscatter B [USGS]--Offshore of Santa Barbara, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3281 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3281) of the Offshore of Santa Barbara map area, California. The...

  5. Backscatter A [CSUMB]--Offshore of Carpinteria, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3261 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3261) of the Offshore of Carpinteria map area, California. The raster...

  6. Backscatter B [USGS]--Offshore of Ventura, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3254 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3254) of the Offshore Ventura map area, California. The raster data...

  7. Backscatter A [CSUMB]--Offshore of Santa Barbara, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3281 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3281) of the Offshore of Santa Barbara map area, California. The...

  8. Backscatter [Swath]-- Offshore of Monterey Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents 2-m-resolution SWATHPlus data for the acoustic-backscatter map of Offshore of Monterey map area, California. These metadata describe...

  9. Backscatter B [USGS]--Offshore of Carpinteria, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3261 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3261) of the Offshore of Carpinteria map area, California. The raster...

  10. Backscatter A [CSUMB]--Offshore of Ventura, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3254 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3254) of the Offshore of Ventura map area, California. The raster...

  11. Backscatter A [CSUMB]--Offshore of Carpinteria, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3261 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3261) of the Offshore of Carpinteria map area, California. The raster...

  12. Impact of carrier heating on backscattering in inversion layers

    Science.gov (United States)

    Clerc, R.; Palestri, P.; Selmi, L.; Ghibaudo, G.

    2011-11-01

    In this work, Monte Carlo simulations and analytical modeling are used to investigate quasi-ballistic transport in nanometric metal oxide semiconductor field effect transistors (MOSFETs). In particular, we examine how the thermal nature of the distribution functions, which is implicitly assumed in the most common expression for the backscattering coefficient, leads to an underestimation of the backscattering coefficient in high field conditions and erroneous velocity distribution along the channel. An improved analytical model is proposed, which better captures the nonequilibrium nature of the distribution function and its impact on backscattering and by allowing velocity profiles to exceed the thermal limit. The improved model provides additional insights on the impact of several assumptions on backscattering and could serve as the basis for the development of physically based compact models of quasi-ballistic MOSFETs.

  13. Reson 8101 multibeam backscatter data from Galvez Bank.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Multibeam backscatter imagery extracted from gridded bathymetry of the Mariana archipelago between the U.S. Territory of Guam and Farallon De Pajaros Island in the...

  14. Moessbauer backscatter spectrometer with full data processing capability

    Energy Technology Data Exchange (ETDEWEB)

    O' Connell, T.; Hartzell, R.; Liebermann, M.

    1976-01-01

    The design and operation of a Moessbauer backscatter spectrometer with full data processing capability is described, and the investigation of the applicability of this technique to a variety of practical metallurgical problems is discussed. (WHK)

  15. Backscatter--Offshore of Refugio Beach Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3319 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3319) of Offshore Refugio Beach map area, California. The raster data...

  16. Backscatter [7125]-- Offshore of Monterey Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents 2-m-resolution Reson 7125 data for the acoustic-backscatter map of Offshore of Monterey map area, California. These metadata describe...

  17. Backscatter A [CSUMB]--Offshore of Santa Barbara, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3281 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3281) of the Offshore of Santa Barbara map area, California. The...

  18. Bathymetry and Acoustic Backscatter: Northern Santa Barbara Channel, Southern California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This report presents bathymetry and acoustic backscatter data collected in July 2008 in the northern Santa Barbara Channel, California, using a bathymetric sidescan...

  19. Aerosol measurement program strategy for global aerosol backscatter model development

    Science.gov (United States)

    Bowdle, David A.

    1985-01-01

    The purpose was to propose a balanced program of aerosol backscatter research leading to the development of a global model of aerosol backscatter. Such a model is needed for feasibility studies and systems simulation studies for NASA's prospective satellite-based Doppler lidar wind measurement system. Systems of this kind measure the Doppler shift in the backscatter return from small atmospheric aerosol wind tracers (of order 1 micrometer diameter). The accuracy of the derived local wind estimates and the degree of global wind coverage for such a system are limited by the local availability and by the global scale distribution of natural aerosol particles. The discussions here refer primarily to backscatter model requirements at CO2 wavelengths, which have been selected for most of the Doppler lidar systems studies to date. Model requirements for other potential wavelengths would be similar.

  20. Backscatter B [USGS]--Offshore of Carpinteria, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3261 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3261) of the Offshore of Carpinteria map area, California. The raster...

  1. Backscatter [8101]--Offshore of Monterey Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents 2-m-resolution Reson 8101 data for the acoustic-backscatter map of the Offshore of Monterey map area, California. These metadata...

  2. Optimal Time Allocation in Backscatter Assisted Wireless Powered Communication Networks

    Science.gov (United States)

    Lyu, Bin; Yang, Zhen; Gui, Guan; Sari, Hikmet

    2017-01-01

    This paper proposes a wireless powered communication network (WPCN) assisted by backscatter communication (BackCom). This model consists of a power station, an information receiver and multiple users that can work in either BackCom mode or harvest-then-transmit (HTT) mode. The time block is mainly divided into two parts corresponding to the data backscattering and transmission periods, respectively. The users first backscatter data to the information receiver in time division multiple access (TDMA) during the data backscattering period. When one user works in the BackCom mode, the other users harvest energy from the power station. During the data transmission period, two schemes, i.e., non-orthogonal multiple access (NOMA) and TDMA, are considered. To maximize the system throughput, the optimal time allocation policies are obtained. Simulation results demonstrate the superiority of the proposed model. PMID:28587171

  3. [Analysis of Scattered Radiation in an Irradiated Body by Means of the Monte Carlo Simulation: Back-scatter Factors of Diagnostic X-rays in the Incident Surface Which is Not Flat].

    Science.gov (United States)

    Kato, Hideki; Minami, Kazuyuki; Asada, Yasuki; Suzuki, Shoichi

    2016-05-01

    To obtain patient entrance surface dose in X-ray photography, a calculation method based on measured exposure or air kerma radiated from X-ray tube is generally used. Two factors are necessary for this calculation: (1) exposure/air kerma to absorb dose conversion factor and (2) back-scatter factor (BSF) based on X-ray quality and on field size. These BSFs are commonly obtained by interpolation from existent data which were given for a water phantom whose entrance surface is flat. Since patient's surface in X-ray photograph is not flat, some error may occur when existent BSF is used in this calculation. In this article, BSF for water phantom with cylindrical surface and elliptic cylinder surface were calculated by means of the Monte Carlo simulation. And these BSFs were compared with BSF for flat surface phantom. As a result (1) radius of curvature of cylindrical phantom or horizontal axis of elliptic cylinder phantom is smaller, (2) half value layer of X-ray is larger, (3) field size is larger, difference of these BSF with that for flat surface phantom tends to be larger. Maximum difference by calculation condition assumed in this article was more than 10%. The cause of this difference is because scattering volume in irradiated body of cylindrical or elliptic cylinder phantom is smaller than flat surface phantom. To obtain patient entrance surface dose more precisely, it is necessary to use BSF respectively calculated for phantom resembling patient's body such as cylindrical or elliptic cylinder phantom by means of the Monte Carlo simulation.

  4. Aerosol Lidar for the Relative Backscatter Amplification Measurements

    Science.gov (United States)

    Razenkov, Igor A.; Banakh, Victor A.; Nadeev, Alexander I.

    2016-06-01

    Backscatter amplification presents only in a turbulent atmosphere, when the laser beam is propagates twice through the same inhomogeneities. We proposed technical solution to detect backscatter amplification. An aerosol micro pulse lidar with a beam expansion via receiving telescope was built to study this effect. Our system allows simultaneous detection of two returns from the same scattering volume: exactly on the axis of the laser beam and off the axis.

  5. A Laboratory Investigation into Microwave Backscattering from Sea Ice

    Science.gov (United States)

    1989-08-01

    froze to form saline slush ice. Continued freezing of * the salty water directly beneath the slush ice led to the formation of columnar-textured...significant influence on backscatter from extremely smooth saline ice at C band. We determined that backscatter at C band from moderately smooth desalinated ...that volume scatter from desalinated ice is important at X band and that it is dominant at Ku band at angles of 100 or more from nadir Conclusions

  6. Constraining the physical properties of Titan's empty lake basins using nadir and off-nadir Cassini RADAR backscatter

    Science.gov (United States)

    Michaelides, R. J.; Hayes, A. G.; Mastrogiuseppe, M.; Zebker, H. A.; Farr, T. G.; Malaska, M. J.; Poggiali, V.; Mullen, J. P.

    2016-05-01

    We use repeat synthetic aperture radar (SAR) observations and complementary altimetry passes acquired by the Cassini spacecraft to study the scattering properties of Titan's empty lake basins. The best-fit coefficients from fitting SAR data to a quasi-specular plus diffuse backscatter model suggest that the bright basin floors have a higher dielectric constant, but similar facet-scale rms surface facet slopes, to surrounding terrain. Waveform analysis of altimetry returns reveals that nadir backscatter returns from basin floors are greater than nadir backscatter returns from basin surroundings and have narrower pulse widths. This suggests that floor deposits are structurally distinct from their surroundings, consistent with the interpretation that some of these basins may be filled with evaporitic and/or sedimentary deposits. Basin floor deposits also express a larger diffuse component to their backscatter, which is likely due to variations in subsurface structure or an increase in roughness at the wavelength scale (Hayes, A.G. et al. [2008]. Geophys. Res. Lett. 35, 9). We generate a high-resolution altimetry radargram of the T30 altimetry pass over an empty lake basin, with which we place geometric constraints on the basin's slopes, rim heights, and depth. Finally, the importance of these backscatter observations and geometric measurements for basin formation mechanisms is briefly discussed.

  7. Enhancement of phonon backscattering due to confinement of ballistic phonon pathways in silicon as studied with a microfabricated phonon spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Otelaja, O. O. [School of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14853 (United States); Robinson, R. D., E-mail: rdr82@cornell.edu [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States)

    2015-10-26

    In this work, the mechanism for enhanced phonon backscattering in silicon is investigated. An understanding of phonon propagation through substrates has implications for engineering heat flow at the nanoscale, for understanding sources of decoherence in quantum systems, and for realizing efficient phonon-mediated particle detectors. In these systems, phonons that backscatter from the bottom of substrates, within the crystal or from interfaces, often contribute to the overall detector signal. We utilize a microscale phonon spectrometer, comprising superconducting tunnel junction emitters and detectors, to specifically probe phonon backscattering in silicon substrates (∼500 μm thick). By etching phonon “enhancers” or deep trenches (∼90 μm) around the detectors, we show that the backscattered signal level increases by a factor of ∼2 for two enhancers versus one enhancer. Using a geometric analysis of the phonon pathways, we show that the mechanism of the backscattered phonon enhancement is due to confinement of the ballistic phonon pathways and increased scattering off the enhancer walls. Our result is applicable to the geometric design and patterning of substrates that are employed in phonon-mediated detection devices.

  8. Lattice constant measurement from electron backscatter diffraction patterns.

    Science.gov (United States)

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

    2017-02-20

    Kikuchi bands in election backscattered diffraction patterns (EBSP) contain information about lattice constants of crystallographic samples that can be extracted via the Bragg equation. An advantage of lattice constant measurement from EBSPs over diffraction (XRD) is the ability to perform local analysis. In this study, lattice constants of cubic STN and cubic YSZ in the pure materials and in co-sintered composites were measured from their EBSPs acquired at 10 kV using a silicon single crystal as a calibration reference. The EBSP distortion was corrected by spherical back projection and Kikuchi band analysis was made using in-house software. The error of the lattice constant measurement was determined to be in the range of 0.09-1.12% compared to values determined by XRD and from literature. The confidence level of the method is indicated by the standard deviation of the measurement, which is approximately 0.04 Å. Studying Kikuchi band size dependence of the measurement precision shows that the measurement error decays with increasing band size (i.e. decreasing lattice constant). However, in practice, the sharpness of wide bands tends to be low due to their low intensity, thus limiting the measurement precision. Possible methods to improve measurement precision are suggested.

  9. Elemental thin film depth profiles by ion beam analysis using simulated annealing - a new tool

    Energy Technology Data Exchange (ETDEWEB)

    Jeynes, C [University of Surrey Ion Beam Centre, Guildford, GU2 7XH (United Kingdom); Barradas, N P [Instituto Tecnologico e Nuclear, E.N. 10, Sacavem (Portugal); Marriott, P K [Department of Statistics, National University of Singapore, Singapore (Singapore); Boudreault, G [University of Surrey Ion Beam Centre, Guildford, GU2 7XH (United Kingdom); Jenkin, M [School of Electronics Computing and Mathematics, University of Surrey, Guildford (United Kingdom); Wendler, E [Friedrich-Schiller-Universitaet Jena, Institut fuer Festkoerperphysik, Jena (Germany); Webb, R P [University of Surrey Ion Beam Centre, Guildford, GU2 7XH (United Kingdom)

    2003-04-07

    Rutherford backscattering spectrometry (RBS) and related techniques have long been used to determine the elemental depth profiles in films a few nanometres to a few microns thick. However, although obtaining spectra is very easy, solving the inverse problem of extracting the depth profiles from the spectra is not possible analytically except for special cases. It is because these special cases include important classes of samples, and because skilled analysts are adept at extracting useful qualitative information from the data, that ion beam analysis is still an important technique. We have recently solved this inverse problem using the simulated annealing algorithm. We have implemented the solution in the 'IBA DataFurnace' code, which has been developed into a very versatile and general new software tool that analysts can now use to rapidly extract quantitative accurate depth profiles from real samples on an industrial scale. We review the features, applicability and validation of this new code together with other approaches to handling IBA (ion beam analysis) data, with particular attention being given to determining both the absolute accuracy of the depth profiles and statistically accurate error estimates. We include examples of analyses using RBS, non-Rutherford elastic scattering, elastic recoil detection and non-resonant nuclear reactions. High depth resolution and the use of multiple techniques simultaneously are both discussed. There is usually systematic ambiguity in IBA data and Butler's example of ambiguity (1990 Nucl. Instrum. Methods B 45 160-5) is reanalysed. Analyses are shown: of evaporated, sputtered, oxidized, ion implanted, ion beam mixed and annealed materials; of semiconductors, optical and magnetic multilayers, superconductors, tribological films and metals; and of oxides on Si, mixed metal silicides, boron nitride, GaN, SiC, mixed metal oxides, YBCO and polymers. (topical review)

  10. TCR backscattering characterization for microwave remote sensing

    Science.gov (United States)

    Riccio, Giovanni; Gennarelli, Claudio

    2014-05-01

    A Trihedral Corner Reflector (TCR) is formed by three mutually orthogonal metal plates of various shapes and is a very important scattering structure since it exhibits a high monostatic Radar Cross Section (RCS) over a wide angular range. Moreover it is a handy passive device with low manufacturing costs and robust geometric construction, the maintenance of its efficiency is not difficult and expensive, and it can be used in all weather conditions (i.e., fog, rain, smoke, and dusty environment). These characteristics make it suitable as reference target and radar enhancement device for satellite- and ground-based microwave remote sensing techniques. For instance, TCRs have been recently employed to improve the signal-to-noise ratio of the backscattered signal in the case of urban ground deformation monitoring [1] and dynamic survey of civil infrastructures without natural corners as the Musmeci bridge in Basilicata, Italy [2]. The region of interest for the calculation of TCR's monostatic RCS is here confined to the first quadrant containing the boresight direction. The backscattering term is presented in closed form by evaluating the far-field scattering integral involving the contributions related to the direct illumination and the internal bouncing mechanisms. The Geometrical Optics (GO) laws allow one to determine the field incident on each TCR plate and the patch (integration domain) illuminated by it, thus enabling the use of a Physical Optics (PO) approximation for the corresponding surface current densities to consider for integration on each patch. Accordingly, five contributions are associated to each TCR plate: one contribution is due to the direct illumination of the whole internal surface; two contributions originate by the impinging rays that are simply reflected by the other two internal surfaces; and two contributions are related to the impinging rays that undergo two internal reflections. It is useful to note that the six contributions due to the

  11. The backscatter electron signal as an additional tool for phase segmentation in electron backscatter diffraction.

    Science.gov (United States)

    Payton, E J; Nolze, G

    2013-08-01

    The advent of simultaneous energy dispersive X-ray spectroscopy (EDS) data collection has vastly improved the phase separation capabilities for electron backscatter diffraction (EBSD) mapping. A major problem remains, however, in distinguishing between multiple cubic phases in a specimen, especially when the compositions of the phases are similar or their particle sizes are small, because the EDS interaction volume is much larger than that of EBSD and the EDS spectra collected during spatial mapping are generally noisy due to time limitations and the need to minimize sample drift. The backscatter electron (BSE) signal is very sensitive to the local composition due to its atomic number (Z) dependence. BSE imaging is investigated as a complimentary tool to EDS to assist phase segmentation and identification in EBSD through examination of specimens of meteorite, Cu dross, and steel oxidation layers. The results demonstrate that the simultaneous acquisition of EBSD patterns, EDS spectra, and the BSE signal can provide new potential for advancing multiphase material characterization in the scanning electron microscope.

  12. New insights into the generalized Rutherford equation for nonlinear neoclassical tearing mode growth from 2D reduced MHD simulations

    Science.gov (United States)

    Westerhof, E.; de Blank, H. J.; Pratt, J.

    2016-03-01

    Two dimensional reduced MHD simulations of neoclassical tearing mode growth and suppression by ECCD are performed. The perturbation of the bootstrap current density and the EC drive current density perturbation are assumed to be functions of the perturbed flux surfaces. In the case of ECCD, this implies that the applied power is flux surface averaged to obtain the EC driven current density distribution. The results are consistent with predictions from the generalized Rutherford equation using common expressions for Δ \\text{bs}\\prime and Δ \\text{ECCD}\\prime . These expressions are commonly perceived to describe only the effect on the tearing mode growth of the helical component of the respective current perturbation acting through the modification of Ohm’s law. Our results show that they describe in addition the effect of the poloidally averaged current density perturbation which acts through modification of the tearing mode stability index. Except for modulated ECCD, the largest contribution to the mode growth comes from this poloidally averaged current density perturbation.

  13. A global-scale model of aerosol backscatter at CO2 wavelengths for satellite-based lidar sensors

    Science.gov (United States)

    Bowdle, David A.

    1986-01-01

    The status of a global-scale model of background aerosol backscatter cross-sections at CO2 wavelengths is described. The model needs, strategy, concept, parameters, and capabilities are addressed, and the data base is discussed, concluding data selection, CO2 backscatter measurements, aerosol optical measurements, aerosol microphysical measurements, water vapor measurements, and data analysis. Strong evidence is reported for a 'universal' background tropospheric aerosol population. Typical background backscatter values at CO2 wavelengths appear to be about 3 x 10 to the -11th to 8 x 10 to the -11th/m/sr. Background signatures are evident in most aerosol data sets which have global-scale coverage in space or time.

  14. Backscattering of linearly polarized light from turbid tissue-like scattering medium with rough surface

    Science.gov (United States)

    Doronin, Alexander; Tchvialeva, Lioudmila; Markhvida, Igor; Lee, Tim K.; Meglinski, Igor

    2016-07-01

    In the framework of further development of a unified computational tool for the needs of biomedical optics, we introduce an electric field Monte Carlo (MC) model for simulation of backscattering of coherent linearly polarized light from a turbid tissue-like scattering medium with a rough surface. We consider the laser speckle patterns formation and the role of surface roughness in the depolarization of linearly polarized light backscattered from the medium. The mutual phase shifts due to the photons' pathlength difference within the medium and due to reflection/refraction on the rough surface of the medium are taken into account. The validation of the model includes the creation of the phantoms of various roughness and optical properties, measurements of co- and cross-polarized components of the backscattered/reflected light, its analysis and extensive computer modeling accelerated by parallel computing on the NVIDIA graphics processing units using compute unified device architecture (CUDA). The analysis of the spatial intensity distribution is based on second-order statistics that shows a strong correlation with the surface roughness, both with the results of modeling and experiment. The results of modeling show a good agreement with the results of experimental measurements on phantoms mimicking human skin. The developed MC approach can be used for the direct simulation of light scattered by the turbid scattering medium with various roughness of the surface.

  15. Ultrasonic tissue characterization with integrated backscatter. Acute myocardial ischemia, reperfusion, and stunned myocardium in patients

    Energy Technology Data Exchange (ETDEWEB)

    Milunski, M.R.; Mohr, G.A.; Perez, J.E.; Vered, Z.; Wear, K.A.; Gessler, C.J.; Sobel, B.E.; Miller, J.G.; Wickline, S.A. (Washington Univ., St. Louis, MO (USA))

    1989-09-01

    We have previously shown in studies of experimental animals that myocardium exhibits a cardiac cycle-dependent variation of integrated backscatter that reflects regional myocardial contractile performance and that is blunted promptly after arterial occlusion and recovers after reperfusion. To define the clinical utility of ultrasonic tissue characterization with integrated backscatter for detection of acute myocardial infarction and reperfusion, 21 patients (14 men and seven women) were studied in the cardiac care unit within the first 24 hours (mean time, 11.3 hours; range, 3.5-23.8 hours) after the onset of symptoms indicative of acute myocardial infarction with conventional two-dimensional and M-mode echocardiography and with analysis of integrated backscatter. The magnitude of cyclic variation of integrated backscatter was measured from several sites within acute infarct regions and normal regions remote from the infarct zone for each patient. The average magnitude of cyclic variation among all patients (n = 21) was 4.8 +/- 0.5 dB in normal regions compared with 0.8 +/- 0.3 dB in infarct regions (p less than 0.05) within the first 24 hours after the onset of symptoms. Among the patients who had two studies, 15 (mean, 7.1 days; range, 2-31 days for second study) underwent coronary arteriography to define vessel patency. In patients with vessels with documented patency (n = 10), the magnitude of cyclic variation in infarct regions increased over time from 1.3 +/- 0.6 to 2.5 +/- 0.5 dB from the initial to final study (p less than 0.05). Patients with occluded infarct-related arteries (n = 5) exhibited no significant recovery of cyclic variation (0.3 +/- 0.3-0.6 +/- 0.3 dB). A blinded analysis of standard two-dimensional echocardiographic images revealed no significant recovery of wall thickening in either group over the same time intervals.

  16. Angioplastia infra-inguinal em pacientes com isquemia crítica grau III, categoria 5 de Rutherford Infra-inguinal angioplasty in patients with critical limb ischemia Rutherford grade III, category 5

    Directory of Open Access Journals (Sweden)

    Abdo Farret Neto

    2008-06-01

    Full Text Available OBJETIVO: Analisar a eficiência da angioplastia primária infra-inguinal como método de salvamento de membros em pacientes portadores de lesões tróficas por isquemia crítica. MATERIAIS E MÉTODOS: Foram analisados 36 pacientes submetidos a angioplastias primárias sem stent. Todos os pacientes apresentavam isquemia crítica com lesão trófica - grau III, categoria 5 de Rutherford -, sendo 17 lesões na artéria femoral superficial, 16 na artéria poplítea e 51 em artérias da perna, totalizando 84 angioplastias. Foram analisadas também as prevalências em relação a sexo, membro afetado, idade e principais comorbidades, sendo tecidas considerações técnicas sobre os procedimentos, assim como os materiais utilizados. RESULTADOS: Considerou-se sucesso quando a lesão trófica que motivou a angioplastia cicatrizou, ou o nível de amputação limitou-se a artelhos ou ao antepé, sem ter havido necessidade de procedimento cirúrgico de reconstituição do fluxo sanguíneo (bypass, independentemente de tempo, drogas associadas e números de desbridamentos realizados. CONCLUSÃO: As angioplastias no segmento femoropoplíteo e infrapoplíteo são procedimentos de elevado sucesso técnico, baixa morbidade e mortalidade, constituindo-se procedimento eficaz em pacientes com isquemia crítica de membro inferior.OBJECTIVE: To evaluate the efficacy of infra-inguinal, primary angioplasty as a method of limb salvage in patients with trophic lesions secondary to critical ischemia. MATERIALS AND METHODS: Thirty-six patients submitted to primary percutaneous transluminal angioplasty without stenting were evaluated. All of them presented critical limb ischemia with trophic lesion (Rutherford grade III, category 5. Eighty-four angioplasties were performed for 17 lesions in superficial femoral artery, 16 lesions in popliteal artery, and 51 lesions in below-knee arteries. Additionally, prevalence in relation to sex, age, limb involved and main comorbidities

  17. Effect of intervening tissues on ultrasonic backscatter measurements of bone: An in vitro study.

    Science.gov (United States)

    Hoffmeister, Brent K; Spinolo, P Luke; Sellers, Mark E; Marshall, Peyton L; Viano, Ann M; Lee, Sang-Rok

    2015-10-01

    Ultrasonic backscatter techniques are being developed to diagnose osteoporosis. Tissues that lie between the transducer and the ultrasonically interrogated region of bone may produce errors in backscatter measurements. The goal of this study is to investigate the effects of intervening tissues on ultrasonic backscatter measurements of bone. Measurements were performed on 24 cube shaped specimens of human cancellous bone using a 5 MHz transducer. Measurements were repeated after adding a 1 mm thick plate of cortical bone to simulate the bone cortex and a 3 cm thick phantom to simulate soft tissue at the hip. Signals were analyzed to determine three apparent backscatter parameters (apparent integrated backscatter, frequency slope of apparent backscatter, and frequency intercept of apparent backscatter) and three backscatter difference parameters [normalized mean backscatter difference (nMBD), normalized slope of the backscatter difference, and normalized intercept of the backscatter difference]. The apparent backscatter parameters were impacted significantly by the presence of intervening tissues. In contrast, the backscatter difference parameters were not affected by intervening tissues. However, only one backscatter difference parameter, nMBD, demonstrated a strong correlation with bone mineral density. Thus, among the six parameters tested, nMBD may be the best choice for in vivo backscatter measurements of bone when intervening tissues are present.

  18. Ray-Based Calculations of Backscatter in Laser Fusion Targets

    Energy Technology Data Exchange (ETDEWEB)

    Strozzi, D J; Williams, E A; Hinkel, D E; Froula, D H; London, R A; Callahan, D A

    2008-02-26

    A steady-state model for Brillouin and Raman backscatter along a laser ray path is presented. The daughter plasma waves are treated in the strong damping limit, and have amplitudes given by the (linear) kinetic response to the ponderomotive drive. Pump depletion, inverse-bremsstrahlung damping, bremsstrahlung emission, Thomson scattering off density fluctuations, and whole-beam focusing are included. The numerical code deplete, which implements this model, is described. The model is compared with traditional linear gain calculations, as well as 'plane-wave' simulations with the paraxial propagation code pf3d. Comparisons with Brillouin-scattering experiments at the OMEGA Laser Facility [T. R. Boehly et al., Opt. Commun. 133, p. 495 (1997)] show that laser speckles greatly enhance the reflectivity over the deplete results. An approximate upper bound on this enhancement, motivated by phase conjugation, is given by doubling the deplete coupling coefficient. Analysis with deplete of an ignition design for the National Ignition Facility (NIF) [J. A. Paisner, E. M. Campbell, and W. J. Hogan, Fusion Technol. 26, p. 755 (1994)], with a peak radiation temperature of 285 eV, shows encouragingly low reflectivity. Doubling the coupling to bound the speckle enhancement suggests a less optimistic picture. Re-absorption of Raman light is seen to be significant in this design.

  19. Criteria of backscattering in chiral one-way photonic crystals

    Science.gov (United States)

    Cheng, Pi-Ju; Chang, Shu-Wei

    2016-03-01

    Optical isolators are important devices in photonic circuits. To reduce the unwanted reflection in a robust manner, several setups have been realized using nonreciprocal schemes. In this study, we show that the propagating modes in a strongly-guided chiral photonic crystal (no breaking of the reciprocity) are not backscattering-immune even though they are indeed insensitive to many types of scatters. Without the protection from the nonreciprocity, the backscattering occurs under certain circumstances. We present a perturbative method to calculate the backscattering of chiral photonic crystals in the presence of chiral/achiral scatters. The model is, essentially, a simplified analogy to the first-order Born approximation. Under reasonable assumptions based on the behaviors of chiral photonic modes, we obtained the expression of reflection coefficients which provides criteria for the prominent backscattering in such chiral structures. Numerical examinations using the finite-element method were also performed and the results agree well with the theoretical prediction. From both our theory and numerical calculations, we find that the amount of backscattering critically depends on the symmetry of scatter cross sections. Strong reflection takes place when the azimuthal Fourier components of scatter cross sections have an order l of 2. Chiral scatters without these Fourier components would not efficiently reflect the chiral photonic modes. In addition, for these chiral propagating modes, disturbances at the most significant parts of field profiles do not necessarily result in the most effective backscattering. The observation also reveals what types of scatters or defects should be avoided in one-way applications of chiral structures in order to minimize the backscattering.

  20. Monte Carlo simulations as a feasibility tool for non-metallic land-mine detection by thermal-neutron backscattering

    NARCIS (Netherlands)

    Maucec, M; de Meijer, RJ

    2002-01-01

    The use of Monte Carlo simulations is presented for modelling a simplified land-mine detector system with thermal neutron backscattering (TNB) analysis based on a Cf-252-neutron source. Different aspects and a variety of external conditions, related to localisation and identification of a buried obj

  1. PIXE-RBS analysis on potteries unearthed from Lijiaba Site

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Q.Q.; Zhu, J.J.; Liu, M.T.; Zhou, Z. [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 (China); An, Z., E-mail: anzhu@scu.edu.cn [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 (China); Huang, W.; He, Y.H.; Zhao, D.Y. [School of History and Culture, Sichuan University, Chengdu 610064 (China)

    2013-02-01

    A simultaneous proton induced X-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) analysis using 2 MeV proton beam and an aluminum funny filter was performed to identify and characterize elemental composition of 52 pottery shards in Shang-Zhou Dynasty (B.C.1700–B.C.221) unearthed from the Lijiaba Site, one of the habitations of Ba clan in the Three Gorges reservoir area in China. From the result of factor analysis of elemental composition, there was no obvious element assemblage phenomenon among the pottery shards with different types, which may suggest that there was no special clay source for special pottery at that time. Furthermore, a group of pottery elemental data from the Jinsha Site (B.C.1200–B.C.650) of Chengdu in China, the representative relic of Shu culture, was also employed to compare with those from the Lijiaba Site, and an obvious difference in elemental composition was observed, which perhaps indicated that only based on the elemental analysis of these potteries, no evidence of interchange was found between the two sites.

  2. PIXE-RBS analysis on potteries unearthed from Lijiaba Site

    Science.gov (United States)

    Wu, Q. Q.; Zhu, J. J.; Liu, M. T.; Zhou, Z.; An, Z.; Huang, W.; He, Y. H.; Zhao, D. Y.

    2013-02-01

    A simultaneous proton induced X-ray emission (PIXE) and Rutherford backscattering spectrometry (RBS) analysis using 2 MeV proton beam and an aluminum funny filter was performed to identify and characterize elemental composition of 52 pottery shards in Shang-Zhou Dynasty (B.C.1700-B.C.221) unearthed from the Lijiaba Site, one of the habitations of Ba clan in the Three Gorges reservoir area in China. From the result of factor analysis of elemental composition, there was no obvious element assemblage phenomenon among the pottery shards with different types, which may suggest that there was no special clay source for special pottery at that time. Furthermore, a group of pottery elemental data from the Jinsha Site (B.C.1200-B.C.650) of Chengdu in China, the representative relic of Shu culture, was also employed to compare with those from the Lijiaba Site, and an obvious difference in elemental composition was observed, which perhaps indicated that only based on the elemental analysis of these potteries, no evidence of interchange was found between the two sites.

  3. Modeling multi-frequency diurnal backscatter from a walnut orchard

    Science.gov (United States)

    Mcdonald, Kyle C.; Dobson, Myron C.; Ulaby, Fawwaz T.

    1991-01-01

    The Michigan Microwave Canopy Scattering Model (MIMICS) is used to model scatterometer data that were obtained during the August 1987 EOS (Earth Observing System) synergism study. During this experiment, truck-based scatterometers were used to measure radar backscatter from a walnut orchard in Fresno County, California. Multipolarized L- and X-band data were recorded for orchard plots for which dielectric and evapotranspiration characteristics were monitored. MIMICS is used to model a multiangle data set in which a single orchard plot was observed at varying impedance angles and a series of diurnal measurements in which backscatter from this same plot was measured continuously over several 24-h periods. MIMICS accounts for variations in canopy backscatter driven by changes in canopy state that occur diurnally as well as on longer time scales. L-band backscatter is dependent not only on properties of the vegetation but also on properties of the underlying soil surface. The behavior of the X-band backscatter is dominated by properties of the tree crowns.

  4. Development and demonstration of a high-altitude atmospheric backscatter Lidar system

    Science.gov (United States)

    Dolash, Thomas M.; Garvey, John; Leonelli, Joseph; Bradford, Mark; Rose, Lynn

    1994-06-01

    Battelle has designed and fabricated an upward-looking atmospheric backscatter lidar for high-altitude airborne applications. The compact, rugged system was assembled and integrated into a cupola on top of a Lear 36 aircraft to provide particle backscatter data and aerosol profile distributions of cirrus clouds occurring between 50,000 and 100,000 ft ASL. The high altitude airborne lidar system consists of a laser transmitter operating at 532 and 1064 nm simultaneously with output energy of 75 mJ at both wavelengths and a collecting telescope aperture of 10 inches in diameter. Laser backscatter energy is collected and directed via a dichroic beamsplitter to two avalanche photodetectors (APD) through narrow bandpass optical filters at 532 and 1064 nm. The outputs of the APDs are digitized by a 10-bit, 100-MHz transient digitizer before being recorded to a 1.2-Gbyte hard disk with IRIG timing for data analysis. This paper describes the lidar system design, predicted performance, and some of the operational challenges.

  5. Sensitivity of L-Band SAR Backscatter to Aboveground Biomass of Global Forests

    Directory of Open Access Journals (Sweden)

    Yifan Yu

    2016-06-01

    Full Text Available Synthetic Aperture Radar (SAR backscatter measurements are sensitive to forest aboveground biomass (AGB, and the observations from space can be used for mapping AGB globally. However, the radar sensitivity saturates at higher AGB values depending on the wavelength and geometry of radar measurements, and is influenced by the structure of the forest and environmental conditions. Here, we examine the sensitivity of SAR at the L-band frequency (~25 cm wavelength to AGB in order to examine the performance of future joint National Aeronautics and Space Administration, Indian Space Research Organisation NASA-ISRO SAR mission in mapping the AGB of global forests. For SAR data, we use the Phased Array L-Band SAR (PALSAR backscatter from the Advanced Land Observing Satellite (ALOS aggregated at a 100-m spatial resolution; and for AGB data, we use more than three million AGB values derived from the Geoscience Laser Altimeter System (GLAS LiDAR height metrics at about 0.16–0.25 ha footprints across eleven different forest types globally. The results from statistical analysis show that, over all eleven forest types, saturation level of L-band radar at HV polarization on average remains ≥100 Mg·ha−1. Fresh water swamp forests have the lowest saturation with AGB at ~80 Mg·ha−1, while needleleaf forests have the highest saturation at ~250 Mg·ha−1. Swamp forests show a strong backscatter from the vegetation-surface specular reflection due to inundation that requires to be treated separately from those on terra firme. Our results demonstrate that L-Band backscatter relations to AGB can be significantly different depending on forest types and environmental effects, requiring multiple algorithms to map AGB from time series of satellite radar observations globally.

  6. How does the Warm Breeze affect the heliospheric backscatter glow of interstellar neutral helium?

    Science.gov (United States)

    Bzowski, Maciej; Kubiak, Marzena; Sokół, Justyna

    2017-04-01

    Based on direct sampling observations of interstellar neutral helium (ISN He) by IBEX, we have discovered a new population of ISN He, dubbed the Warm Breeze (WB), and identified it as the secondary population of ISN He, created in the outer heliosheath. The WB flow is twice slower and hotter by half than the primary ISN He, and it flows from a direction different by 5° in longitude and 6° in latitude. Its density is 5% of that of ISN He. ISN He had been extensively studied in the past by analysis of the backscatter glow, but the WB was not considered in these analyses because its existence had been unknown. However, the ISN He speed and temperature derived from analyses of the heliospheric helium glow tended to be systematically biased towards slower speeds or higher temperatures with respect to those obtained from direct-sampling experiments. We calculate the expected intensity of the backscatter glow due to the ISN He and WB using the best-fit parameters recently obtained from IBEX direct-sampling observations and compare its distribution in the sky with that expected only from the primary ISN gas. In the modeling, we use a time-dependent hot model of Maxwell-Boltzmann distribution of ISN gas and carefully account for the bulk velocities and temperatures of the direct and indirect beams of the two populations, as well as for details of the ionization rates. We discuss differences between intensities of the backscatter glow expected from different regions in the sky, obtained for the models including and excluding the WB and point out that the absence of the WB component in the modeling may have biased the parameters of the primary population of ISN He derived from the helium backscatter glow and lead to underestimating the Mach number of the flow, due to a slower bulk speed or higher temperature.

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

    Science.gov (United States)

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

    2009-02-01

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

  8. Ion beam analysis of Cu(In,Ga)Se{sub 2} thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Karydas, A.G. [International Atomic Energy Agency (IAEA), IAEA Laboratories, Nuclear Science and Instrumentation Laboratory, A-2444 Seibersdorf (Austria); Institute of Nuclear and Particle Physics, NCSR “Demokritos”, 153 10 Aghia Paraskevi, Athens Greece (Greece); Streeck, C. [Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin (Germany); Radovic, I. Bogdanovic [Ruđer Bošković Institute (RBI), Zagreb (Croatia); Kaufmann, C.; Rissom, T. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Beckhoff, B. [Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin (Germany); Jaksic, M. [Ruđer Bošković Institute (RBI), Zagreb (Croatia); Barradas, N.P. [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, E. N. 10, Apartado 21, 2686-953 Sacavém (Portugal)

    2015-11-30

    Graphical abstract: - Highlights: • Elemental depth profiles for various CIGS thin films were quantitatively determined. • Pure absorbers, complete cell and bilayer solar cells were prepared and analyzed. • Synergistic PIXE and RBS analysis of thin solar cells using alpha beam particles. • High energy alpha beam resolved completely the Indium depth profile. • Synchrotron based Reference Free GIXRF quantitative analysis validated IBA results. - Abstract: The present work investigates the potential of ion beam analysis (IBA) techniques such as the Rutherford backscattering spectrometry (RBS) and particle induced X-ray emission (PIXE) using helium ions to provide quantitative in-depth elemental analysis of various types of Cu(In,Ga)Se{sub 2} thin films. These films with a thickness of about 2 μm are used as absorber layers in photovoltaic devices with continuously increasing the performance of this technology. The preparation process generally aims to obtain an in-depth gradient of In and Ga concentrations that optimizes the optoelectronic and electrical properties of the solar cell. The measurements were performed at directly accessible single or double layered CIGS absorbers and at buried absorbers in completed thin film solar cells. The IBA data were analyzed simultaneously in order to derive best fitted profiles that match all experimental RBS and PIXE spectra. For some samples elemental profiles deduced form synchrotron based, reference free grazing incidence X-ray fluorescence analysis were compared with the IBA results and an overall good agreement was observed within quoted uncertainties.

  9. Measurement of backscatter factor for diagnostic radiology: methodology and uncertainties

    Energy Technology Data Exchange (ETDEWEB)

    Rosado, P.H.G.; Nogueira, M.D.S.; Squair, P.L.; Da Silva, T.A. [Centro de Desenvolvimento da Tecnoogia Nuclear (CDTN/CNEN) 30123-970, Minas Gerais (Brazil)]. e-mail: phgr@cdtn.br

    2007-07-01

    Full text: Backscatter factors were experimentally determined for the diagnostic X-ray qualities recommended by the International Electrotechnical Commission (IEC) for primary beams (RQR). Harshaw LiF-1 100H thermoluminescent dosemeters used for determining the backscatter were calibrated against an ionization chamber traceable to the National Metrology Laboratory. A 300mm x 300mm x 150mm PMMA slab phantom was used for deep-doses measurements. To perform the in-phantom measurements, the dosemeters were placed in the central axis of the x-ray beam at five different depths d in the phantom (5, 10, 15, 25 and 35 mm) upstream the beam direction. The typical combined standard uncertainty of the backscatter factor value was 6%. The main sources of uncertainties were the calibration procedure, the TLD dosimetry and the use of deep-dose curves. (Author)

  10. Backscatter signatures of biological aerosols in the infrared.

    Science.gov (United States)

    Thrush, Evan; Salciccioli, Nicolas; Brown, David M; Siegrist, Karen; Brown, Andrea M; Thomas, Michael E; Boggs, Nathan; Carter, Christopher C

    2012-04-20

    To develop a deeper understanding of the optical signatures of both biological aerosols and potential interferents, we made field measurements of optical cross sections and compared them to model-based predictions. We measured aerosol cross sections by conducting a hard-target calibration of a light detection and ranging system (LIDAR) based on the Frequency Agile Laser (FAL). The elastic backscatter cross sections are estimated at 19 long-wave infrared (LWIR) wavelengths spanning the range from 9.23 to 10.696 μm. The theoretical modeling of the elastic backscatter cross sections is based on the measured refractive index and size distribution of the aerosols, which are used as inputs into Mie calculations. Both model calculations and experimental measurements show good agreement and also indicate the presence of spectral features based on single particle absorption in the backscatter cross sections that can be used as a basis for discrimination for both standoff and point sensors.

  11. Effects of optical backscattering on silicon photonic hybrid laser performance

    Science.gov (United States)

    Pacradouni, V.; Klein, J.; Pond, J.

    2016-04-01

    We present numerical results on the effect of backscattering at the junctions of double bus ring resonators in a Vernier ring hybrid laser design. The structure is comprised off a pair of III-V gain media evanescently coupled to a silicon on insulator racetrack comprised of a pair of double bus ring resonators coupled together through straight and flared waveguide sections. We show how the small backscattering at the ring resonator junctions has the effect of splitting and shifting the resonances off the clockwise and counter clockwise propagating modes thereby modifying the feedback spectrum from the ideal case. We then simulate results such as light current (LI) curves, relative intensity noise (RIN) and laser spectrum, and compare the laser performance including backscattering effects with the ideal case.

  12. Laser light backscatter from intermediate and high Z plasmas

    Science.gov (United States)

    Berger, R. L.; Constantin, C.; Divol, L.; Meezan, N.; Froula, D. H.; Glenzer, S. H.; Suter, L. J.; Niemann, C.

    2006-09-01

    In experiments at the Omega Laser Facility [J. M. Soures et al., Fusion Technol. 30, 492 (1996)], stimulated Brillouin backscatter (SBS) from gasbags filled with krypton and xenon gases was ten times lower than from CO2-filled gasbags with similar electron densities. The SBS backscatter was a 1%-5% for both 527 and 351nm interaction beams at an intensity of ˜1015W /cm2. The SRS backscatter was less than 1%. The 351nm interaction beam is below the threshold for filamentation and the SBS occurs in the density plateau between the blast waves. Inverse bremsstrahlung absorption of the incident and SBS light account for the lower reflectivity from krypton than from CO2. The 527nm interaction beam filaments in the blowoff plasma before the beam propagates through the blast wave, where it is strongly absorbed. Thus, most of the 527nm SBS occurs in the flowing plasma outside the blast waves.

  13. Bruce Thompson: Adventures and advances in ultrasonic backscatter

    Science.gov (United States)

    Margetan, Frank J.

    2012-05-01

    Over the course of his professional career Dr. R. Bruce Thompson published several hundred articles on non-destructive evaluation, the majority dealing with topics in ultrasonics. One longtime research interest of Dr. Thompson, with applications both to microstructure characterization and defect detection, was backscattered grain noise in metals. Over a 20 year period he led a revolving team of staff members and graduate students investigating various aspects of ultrasonic backscatter. As a member of that team I had the privilege of working along side Dr. Thompson for many years, serving as a sort of Dr. Watson to Bruce's Sherlock Holmes. This article discusses Dr. Thompson's general approaches to modeling backscatter, the research topics he chose to explore to systematically elucidate a better understanding of the phenomena, and the many contributions to the field achieved under his leadership. The backscatter work began in earnest around 1990, motivated by a need to improve inspections of aircraft engine components. At that time Dr. Thompson launched two research efforts. The first led to the heuristic Independent Scatterer Model which could be used to estimate the average grain noise level that would be seen in any given ultrasonic inspection. There the contribution from the microstructure was contained in a measureable parameter known as the Figure-of-Merit or FOM. The second research effort, spearheaded by Dr. Jim Rose, led to a formal relationship between FOM and details of the metal microstructure. The combination of the Independent Scattering Model and Rose's formalism provided a powerful tool for investigating backscatter in metals. In this article model developments are briefly reviewed and several illustrative applications are discussed. These include: the determination of grain size and shape from ultrasonic backscatter; grain noise variability in engine-titanium billets and forgings; and the design of ultrasonic inspection systems to improve defect

  14. Weak "A" blood subgroup discrimination by a rheo-optical method: a new application of laser backscattering

    Science.gov (United States)

    Rasia, Rodolfo J.; Rasia-Valverde, Juana R.; Stoltz, Jean F.

    1996-01-01

    Laser backscattering is an excellent tool to investigate size and concentration of suspended particles. It was successfully applied to the analysis of erythrocyte aggregation. A method is proposed that applies laser backscattering to the evaluation of the strength of the immunologic erythrocyte agglutination by approaching the energy required for the mechanical dissociation of agglutinates. Mills and Snabre have proposed a theory of laser backscattering for erythrocyte aggregation analysis. It is applied here to analyze the dissociation process of erythrocyte agglutinates performed by imposing a constant shear rate to the agglutinate suspension in a couette viscometer until a dispersion of isolated red cells is attained. Experimental verifications of the method were performed on the erythrocytes of the ABO group reacting against an anti-A test serum in twofold series dilutions. Spent energy is approached by a numerical process carried out on the backscattered intensity data registered during mechanical dissociation. Velocities of agglutination and dissociation lead to the calculation of dissociation parameters These values are used to evaluate the strength of the immunological reaction and to discriminate weak subgroups of ABO system.

  15. Recovering an electromagnetic obstacle by a few phaseless backscattering measurements

    Science.gov (United States)

    Li, Jingzhi; Liu, Hongyu; Wang, Yuliang

    2017-03-01

    We consider the electromagnetic scattering from a convex polyhedral PEC or PMC obstacle due to a time-harmonic incident plane wave. It is shown that the modulus of the far-field pattern in the backscattering aperture possesses a certain local maximum behavior. Using the local maximum indicating phenomena, one can determine the exterior unit normal directions, as well as the face areas, of the front faces of the obstacle. Then we propose a recovery scheme of reconstructing the obstacle by phaseless backscattering measurements. This work significantly extends our recent study in Li and Liu (2014 preprint) from two dimensions and acoustic scattering to the more challenging three dimensions and electromagnetic scattering.

  16. Seabed habitat mapping employing single and multi-beam backscatter data: A case study from the western continental shelf of India

    Science.gov (United States)

    Haris, K.; Chakraborty, Bishwajit; Ingole, Baban; Menezes, Andrew; Srivastava, Ratan

    2012-10-01

    Acoustic backscatter from multi-beam echo-sounder (MBES) and dual-frequency single-beam echo-sounding systems (SBES) operable at 95 kHz and 33/210 kHz, respectively, were used to study the distribution of sediment texture and benthic macro-fauna along the central part of the western continental shelf of India (off Goa). To characterize the continental shelf seafloor, single-beam and multi-beam backscatter signals were acquired along with grab sediment samples. The relationships between processed acoustic backscatter strength, grain size, and benthic macro-fauna abundance were demonstrated employing clustering technique (PCA) and Geographic Information System (GIS) based mapping. The clustering analysis delineated that the backscatter values at three frequencies are strongly correlated with both substrate type and faunal functional groups. The preferences of deposit feeders (soft body benthic macro-fauna) for the fine-sediment regions and filter feeders (hard body benthic macro-fauna) for coarse sediment regions were linked to the variations in sediment granulometry as well as backscatter strengths in the study area. This study further demonstrates the utility of high frequency backscatter data employing echo-sounding systems towards the interpretation of seafloor sediments and benthic habitat characteristics across large areas of seafloor.

  17. Particle-Induced X-Ray Emission Analysis of Atmospheric Aerosols

    Science.gov (United States)

    Gleason, Colin; Harrington, Charles; Schuff, Katie; Battaglia, Maria; Moore, Robert; Turley, Colin; Vineyard, Michael; Labrake, Scott

    2010-11-01

    We are developing a research program in ion-beam analysis (IBA) of atmospheric aerosols at the Union College Ion-Beam Analysis Laboratory to study the transport, transformation, and effects of airborne pollution in Upstate New York. The simultaneous applications of the IBA techniques of particle-induced X-ray emission (PIXE), Rutherford back-scattering spectrometry (RBS), particle-induced gamma-ray emission (PIGE), and proton elastic scattering analysis (PESA) is a powerful tool for the study of airborne pollution because they are non-destructive and provide quantitative information on nearly all elements of the periodic table. PIXE is the main IBA technique because it is able to detect nearly all elements from Na to U with high sensitivities and low detection limits. The aerosol samples are collected with cascade impactors that allow for the study of particulate matter as a function of particle size and the samples are analyzed using proton beams with energies around 2 MeV from the Union College 1.1-MV Pelletron Accelerator. The emitted X-rays are measured using a silicon drift detector with a resolution of 136 eV. We will describe how the aerosol samples were collected, discuss the PIXE analysis, and present preliminary results.

  18. Optical backscattering properties of the "clearest" natural waters

    Directory of Open Access Journals (Sweden)

    M. S. Twardowski

    2007-07-01

    Full Text Available During the BIOSOPE field campaign October–December 2004, measurements of inherent optical properties from the surface to 500 m depth were made with a ship profiler at stations covering over ~8000 km through the Southeast Pacific Ocean. Data from a ~3000 km section containing the very clearest waters in the central gyre are reported here. The total volume scattering function at 117°, βt(117°, was measured with a WET Labs ECO-BB3 sensor at 462, 532, and 650 nm with estimated uncertainties of 2×10−5, 5×10−6, and 2×10−6 m−1 sr−1, respectively. These values were approximately 6%, 3%, and 3% of the scattering by pure seawater at their respective wavelengths. From a methodological perspective, there were several results:

    bbp distributions were resolvable even though some of the values from the central gyre were an order of magnitude lower than the lowest previous measurements in the literature;
    – Direct in-situ measurements of instrument dark offsets were necessary to accurately resolve backscattering at these low levels;
    – accurate pure seawater backscattering values are critical in determining particulate backscattering coefficients in the open ocean (not only in these very clear waters; the pure water scattering values determined by Buiteveld et al. (1994 with a [1 + 0.3S/37] adjustment for salinity based on Morel (1974 appear to be the most accurate estimates, with aggregate accuracies as low as a few percent; and
    – closure was demonstrated with subsurface reflectance measurements reported by Morel et al. (2007 within instrument precisions, a useful factor in validating the backscattering measurements.

    This methodology enabled several observations with respect to the hydrography and the use of backscattering as a biogeochemical proxy:

    – The clearest waters sampled were found at

  19. Optical backscattering properties of the "clearest" natural waters

    Directory of Open Access Journals (Sweden)

    M. S. Twardowski

    2007-11-01

    Full Text Available During the BIOSOPE field campaign October–December 2004, measurements of inherent optical properties from the surface to 500 m depth were made with a ship profiler at stations covering over 8000 km through the Southeast Pacific Ocean. Data from a ~3000 km section containing the very clearest waters in the central gyre are reported here. The total volume scattering function at 117°, βt(117°, was measured with a WET Labs ECO-BB3 sensor at 462, 532, and 650 nm with estimated uncertainties of 2×10-5, 5×10-6, and 2×10-6 m−1 sr−1, respectively. These values were approximately 6%, 3%, and 3% of the volume scattering by pure seawater at their respective wavelengths. From a methodological perspective, there were several results:

    – distributions were resolvable even though some of the values from the central gyre were an order of magnitude lower than the lowest previous measurements in the literature;
    – Direct in-situ measurements of instrument dark offsets were necessary to accurately resolve backscattering at these low levels;
    – accurate pure seawater backscattering values are critical in determining particulate backscattering coefficients in the open ocean (not only in these very clear waters; the pure water scattering values determined by Buiteveld et al. (1994 with a [1+0.3S/37] adjustment for salinity based on Morel (1974 appear to be the most accurate estimates, with aggregate accuracies as low as a few percent; and
    – closure was demonstrated with subsurface reflectance measurements reported by Morel et al. (2007 within instrument precisions, a useful factor in validating the backscattering measurements.

    This methodology enabled several observations with respect to the hydrography and the use of backscattering as a biogeochemical proxy:

    –The clearest waters sampled were found at depths between 300 and 350 m, from 23.5° S

  20. Statistics of the integrated backscatter estimate from a blood-mimicking fluid.

    Science.gov (United States)

    Cakareski, E; Pedersen, P C

    2001-11-01

    This work evaluates the variance of the integrated backscatter (IBS) from moving blood [or blood-mimicking fluid (bmf)] as a way of determining the quality of the mean IBS estimate. The main motivation for this work comes from the fact that absolute IBS values from tissues adjacent to arterial blood can be found by normalizing the measured backscatter energy with the IBS of moving, deaggregated blood. The paper describes the parameters that control the statistics of the IBS estimate, which is calculated for the stochastic ultrasound backscatter signals from flowing blood. It further formulates how the measurement parameters should be specified so that an appropriately low blood IBS variance is ensured or, alternatively, a specified accuracy of the tissue IBS estimate is obtained. First, the paper provides an analytic formulation of the statistics of the IBS, based on a sequence of sampled echoes from a nonstationary Gaussian scattering medium. The analysis incorporates the correlation between the sample values as well as the correlation between the IBS of the individual echoes. The estimate of the mean IBS has been shown to be chi-squared distributed with a determinable order. With the degree of correlation between the samples and between the IBS of individual echoes specified, the number of measurements required to obtain an IBS estimate with a specified variance is readily calculated. Next, a sequence of synthetic echoes is produced and arranged as columns in a data matrix. The echoes are generated such that the second-order statistics along the rows and columns of the matrix match that of actually observed echoes. The actual variance of the mean IBS estimate for the synthetic echoes is calculated and compared with the variance determined from the analytic model, and a good agreement has been found. Finally, sequences of actual backscattered echoes from circulating blood-mimicking fluid are acquired and analyzed to determine the variance of their mean IBS

  1. Influence of Contractility on Myocardial Ultrasonic Integrated Backscatter and Cyclic Variation in Integrated Backscatter

    Institute of Scientific and Technical Information of China (English)

    毕小军; 邓又斌; 潘敏; 杨好意; 向慧娟; 常青; 黎春雷

    2002-01-01

    Summary: To evaluate the effects of left ventricular contractility on the changes of average image intensity (AII) of the myocardial integrated backscatter (IB) and cyclic variation in IB (CVIB), 7 adult mongrel dogs were studied. The magnitude of AII and CVIB were measured from myocardial IB carves before and after dobutamine or propranolol infusion. Dobutamine or propranolol did not affect the magnitude of AII (13.8±0. 7 vs 14.7±0. 5, P>0. 05 or 14.3±0.5 vs 14.2±0. 4, P>0. 05). However, dobutamine produced a significant increase in the magnitude of CVIB (6.8±0.3 vs 9.5 ± 0. 6, P<0. 001) and propranolol induced significant decrease in the magnitude of CVIB (7.1±0. 2 vs 5.2±0. 3, P<0. 001). The changes of the magnitude of AII and CVIB in the myocardium have been demonstrated to reflect different myocardial physiological and pathological changes respectively. The alteration of contractility did not affect the magnitude of AII but induced significant change in CVIB. The increase of left ventricular contractility resulted in a significant rise of the magnitude of CVIB and the decrease of left ventricular contractility resulted in a significant fall of the magnitude of CVIB.

  2. On the maximum backscattering cross section of passive linear arrays

    DEFF Research Database (Denmark)

    Solymar, L.; Appel-Hansen, Jørgen

    1974-01-01

    The maximum backscattering cross section of an equispaced linear array connected to a reactive network and consisting of isotropic radiators is calculated forn = 2, 3, and 4 elements as a function of the incident angle and of the distance between the elements. On the basis of the results obtained...

  3. Backscatter B [USGS]--Offshore of Coal Oil Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3302 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3302) of the Offshore of Coal Oil Point map area, California. The...

  4. Backscatter C [Fugro]--Offshore of Coal Oil Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3302 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3302) of the Offshore of Coal Oil Point map area, California. The...

  5. Lattice constant measurement from electron backscatter diffraction patterns

    DEFF Research Database (Denmark)

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

    2017-01-01

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

  6. Using Back-Scattering to Enhance Efficiency in Neutron Detectors

    CERN Document Server

    Kittelmann, Thomas; Cai, Xiao Xiao; Kanaki, Kalliopi; Cooper-Jensen, Carsten P; Hall-Wilton, Richard

    2015-01-01

    The principle of using strongly scattering materials to recover efficiency in neutron detectors, via back-scattering of unconverted thermal neutrons, is discussed in general. Feasibility of the method is illustrated through Geant4-based simulations of a specific setup involving a moderator-like material placed behind a single layered boron-10 thin film gaseous detector.

  7. Backscatter C [Fugro]--Offshore of Coal Oil Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3302 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3302) of the Offshore of Coal Oil Point map area, California. The...

  8. The Growth and Decay of Equatorial Backscatter Plumes.

    Science.gov (United States)

    1980-02-01

    spatially connected to bottomside backscatter, a feature noted in Jica - marca radar observations that led Woodman and La Hoz (1976) to speculate that...described in Section Ill-B, this pattern of plume growth resembles the "C-shaped" and "fishtail" patterns found in Jica - marca radar RTI displays of 50-MHz

  9. Backscatter B [USGS]--Offshore of Coal Oil Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3302 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3302) of the Offshore of Coal Oil Point map area, California. The...

  10. Radar Backscatter Across the Gulf Stream Sea Surface Temperature Front

    Science.gov (United States)

    Nghiem, S. V.; Li, F. K.; Walsh, E. J.; Lou, S. H.

    1998-01-01

    Ocean backscatter signatures were measured by the Jet Propulsion Laboratory airborne NUSCAT K(sub u)-band scatterometer across the Gulf Stream sea surface temperature front. The measurements were made during the Surface Wave Dynamics Experiment (SWADE) off the coast of Virginia and Maryland in the winter of 1991.

  11. Backscatter gauge description for inspection of neutron absorber content

    Energy Technology Data Exchange (ETDEWEB)

    Dewberry, R. A.; Gibbs, K. M.; Couture, A. H.

    2013-01-19

    This paper describes design, calibration, and testing of a dual He-3 detector neutron backscatter gauge for use in the Savannah River Site Mixed Oxide Fuel project. The gauge is demonstrated to measure boron content and uniformity in concrete slabs used in the facility construction.

  12. Backscatter A [CSUMB]--Offshore Coal Oil Point, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3302 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3302) of the Offshore of Coal Oil Point map area, California. The...

  13. Backscatter A [CSUMB]--Offshore of Ventura, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of SIM 3254 presents data for part of the acoustic-backscatter map (see sheet 3, SIM 3254) of the Offshore of Ventura map area, California. The raster data...

  14. Transport properties and superconductivity in presence of backscattering

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H.; Mattis, D. (Utah Univ., Salt Lake City, UT (United States). Dept. of Physics); Rudin, S. (Army Electronics Technology and Devices Lab., Fort Monmouth, NJ (United States))

    1992-04-20

    In this paper, the authors achieve an exact evaluation of the Kubo formula for electrical resistivity, with a model in which random impurity scattering is parametrized by random back-scattering matrix elements. If the alloy is a superconductor, our theory allows us to correlate T{sub c} with the normal-phase resistivity. The results are in nice agreement with experiment.

  15. Ultrasonic Characterization of Tissues via Backscatter Frequency Dependence

    DEFF Research Database (Denmark)

    Stetson, Paul F.; Sommer, F.G.

    1997-01-01

    , significantly lower mean frequency of ultrasound backscattered from cirrhotic, compared to normal, liver tissue was noted, Studies of benign and malignant liver tumors (hemangiomas and metastases, respectively) indicated differences in frequency content of these tumors, compared to the adjacent normal liver...

  16. Tracking California seafloor seeps with bathymetry, backscatter and ROVs

    Science.gov (United States)

    Orange, Daniel L.; Yun, Janet; Maher, Norman; Barry, James; Greene, Gary

    2002-11-01

    The California (USA) margin includes two different tectonic regimes: subduction north of the Mendocino Triple Junction and translation south. Both margins include seeps, and their distribution can be inferred using seafloor bathymetry and backscatter as well as subsurface seismic data. Anomalous bathymetric and backscatter features related to fluid expulsion include headless submarine canyons, fault zones, anticlines, pockmarks, and mud volcanoes. Anomalous backscatter may be caused by authigenic carbonate (related to the bacterial oxidation of methane) or cold seep clams—both have an impedance and roughness that may be higher than the surrounding seafloor. Remote-operated vehicle (ROV) dives to such suspect seep sites document the presence of extensive authigenic carbonate, areally restricted cold seep communities, carpets of chemoautotrophic bacteria, and bubbling gas. Our operations in the Monterey Bay, on the translational California margin, and the Eel River basin, on the convergent margin, indicate that bathymetric and backscatter maps of the seafloor, if sufficiently high resolution, can be used to map seep sites, and that the distribution of such seeps can be used to constrain subsurface conduits of fluid flow. ROVs, due to their combination of visualization, propulsion, manipulation, sonar, and navigation, provide an excellent platform for ground-truthing, mapping, and sampling seafloor seeps.

  17. Simulation of multistatic and backscattering cross sections for airborne radar

    Science.gov (United States)

    Biggs, Albert W.

    1986-07-01

    In order to determine susceptibilities of airborne radar to electronic countermeasures and electronic counter-countermeasures simulations of multistatic and backscattering cross sections were developed as digital modules in the form of algorithms. Cross section algorithms are described for prolate (cigar shape) and oblate (disk shape) spheroids. Backscattering cross section algorithms are also described for different categories of terrain. Backscattering cross section computer programs were written for terrain categorized as vegetation, sea ice, glacial ice, geological (rocks, sand, hills, etc.), oceans, man-made structures, and water bodies. PROGRAM SIGTERRA is a file for backscattering cross section modules of terrain (TERRA) such as vegetation (AGCROP), oceans (OCEAN), Arctic sea ice (SEAICE), glacial snow (GLASNO), geological structures (GEOL), man-made structures (MAMMAD), or water bodies (WATER). AGCROP describes agricultural crops, trees or forests, prairies or grassland, and shrubs or bush cover. OCEAN has the SLAR or SAR looking downwind, upwind, and crosswind at the ocean surface. SEAICE looks at winter ice and old or polar ice. GLASNO is divided into a glacial ice and snow or snowfields. MANMAD includes buildings, houses, roads, railroad tracks, airfields and hangars, telephone and power lines, barges, trucks, trains, and automobiles. WATER has lakes, rivers, canals, and swamps. PROGRAM SIGAIR is a similar file for airborne targets such as prolate and oblate spheroids.

  18. BackscatterB [Swath]--Offshore of Point Reyes Map Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Point Reyes map area, California. Backscatter data are provided as separate...

  19. BackscatterC [7125]--Offshore of Salt Point Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Salt Point map area, California. Backscatter data are provided as separate...

  20. Characterizing Indian Ocean manganese nodule-bearing seafloor using multi-beam angular backscatter

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Kodagali, V.N.

    backscattering in delineating seafloor parameters characteristic of nodule-rich sediments. In this paper, processed Hydrosweep multi-beam backscatter data from 45 spot locations in the CIOB (where nodule samples are available) were analysed to estimate seafloor...

  1. BackscatterA [8210]--Offshore of Salt Point Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Salt Point map area, California. Backscatter data are provided as separate...

  2. BackscatterA [8101]--Offshore of Point Reyes Map Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Point Reyes map area, California. Backscatter data are provided as separate...

  3. BackscatterC [7125]--Offshore of Point Reyes Map Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Point Reyes map area, California. Backscatter data are provided as separate...

  4. BackscatterB [Swath]--Offshore of Salt Point Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Salt Point map area, California. Backscatter data are provided as separate...

  5. BackscatterA [USGS SWATH]--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Monterey Canyon and Vicinity map area, California. Backscatter data are provided as separate...

  6. BackscatterD [CSUMB Swath]--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Monterey Canyon and Vicinity map area, California. Backscatter data are provided as separate...

  7. Impact of diurnal variation in vegetation water content on radar backscatter from maize during water stress

    NARCIS (Netherlands)

    Van Emmerik, T.H.M.; Dunne, S.C.; Judge, J.; van de Giesen, N.C.

    2014-01-01

    Microwave backscatter from vegetated surfaces is influenced by vegetation structure and vegetation water content (VWC), which varies with meteorological conditions and moisture in the root zone. Radar backscatter observations are used for many vegetation and soil moisture monitoring applications und

  8. Super-virtual Interferometric Separation and Enhancement of Back-scattered Surface Waves

    KAUST Repository

    Guo, Bowen

    2015-08-19

    Back-scattered surface waves can be migrated to detect near-surface reflectors with steep dips. A robust surface-wave migration requires the prior separation of the back-scattered surface-wave events from the data. This separation is often difficult to implement because the back-scattered surface waves are masked by the incident surface waves. We mitigate this problem by using a super-virtual interferometric method to enhance and separate the back-scattered surface waves. The key idea is to calculate the virtual back-scattered surface waves by stacking the resulting virtual correlated and convolved traces associated with the incident and back-scattered waves. Stacking the virtual back-scattered surface waves improves their signal-to-noise ratio and separates the back-scattered surface-waves from the incident field. Both synthetic and field data results validate the robustness of this method.

  9. Multibeam Backscatter Data for Selected U.S. Locations in the Pacific

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Multibeam backscatter imagery extracted from gridded bathymetry for selected U.S. locations in the Pacific. The backscatter datasets include data collected using the...

  10. BackscatterD [CSUMB Swath]--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Monterey Canyon and Vicinity map area, California. Backscatter data are provided as separate...

  11. BackscatterA [USGS SWATH]--Monterey Canyon and Vicinity, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of Monterey Canyon and Vicinity map area, California. Backscatter data are provided as separate...

  12. BackscatterB [Swath]--Offshore of Salt Point Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Salt Point map area, California. Backscatter data are provided as separate...

  13. BackscatterC [7125]--Offshore of Salt Point Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Salt Point map area, California. Backscatter data are provided as separate...

  14. BackscatterC [7125]--Offshore of Point Reyes Map Map Area, California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This part of DS 781 presents data for the acoustic-backscatter map of the Offshore of Point Reyes map area, California. Backscatter data are provided as separate...

  15. Design and Evaluation of joint resistance in SSC Rutherford type cable splices for Torus magnet for the Jefferson Lab 12 GeV Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Ghoshal, Probir K. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Fair, Ruben J. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Kashy, David H. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Legg, Robert A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Rajput-Ghoshal, Renuka [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Hampshire, Damian; Tsui, Yeekin; Haden-Gates, Virginia

    2016-06-01

    The Hall B 3.6-T superconducting torus magnet is being designed and built as part of the Jefferson Lab 12-GeV upgrade. The magnet consists of six trapezoidal coils connected in series, with an operating current of 3770 A. The magnet and the joints (or splices) connecting the coils are all conduction cooled by supercritical 4.6-K helium. This paper studies the design and manufacturing process of the splices made between two SSC Rutherford-type cables and discusses the tests performed to evaluate the performance of the splices under varying incident magnetic fields.

  16. Surface Science Analysis of GaAs Photocathodes Following Sustained Electron Beam Delivery

    Energy Technology Data Exchange (ETDEWEB)

    Shutthanandan, V.; Zhu, Zihua; Stutzman, Marcy L.; Hannon, Fay; Hernandez-Garcia, Carlos; Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana V N T; Thevuthasan, Suntharampillai; Hess, Wayne P.

    2012-06-12

    Degradation of the photocathode materials employed in photoinjectors represents a challenge for sustained operation of nuclear physics accelerators and high power Free Electron Lasers (FEL). Several photocathode degradation processes are suspected, including defect formation by ion back bombardment, photochemistry of surface adsorbed species and irradiation-induced surface defect formation. To better understand the mechanisms of photocathode degradation, we have conducted surface and bulk analysis studies of two GaAs photocathodes removed from the FEL photoinjector after delivering electron beam for a few years. The analysis techniques include Helium Ion Microscopy (HIM), Rutherford Backscattering Spectrometry (RBS), Atomic Force Microscopy (AFM) and Secondary Ion Mass Spectrometry (SIMS). In addition, strained super-lattice GaAs photocathode samples, removed from the CEBAF photoinjector were analyzed using Transmission Electron Microscopy (TEM) and SIMS. This analysis of photocathode degradation during nominal photoinjector operating conditions represents first steps towards developing robust new photocathode designs necessary for generating sub-micron emittance electron beams required for both fourth generation light sources and intense polarized CW electron beams for nuclear and high energy physics facilities.

  17. Compositional analysis of silicon oxide/silicon nitride thin films

    Directory of Open Access Journals (Sweden)

    Meziani Samir

    2016-06-01

    Full Text Available Hydrogen, amorphous silicon nitride (SiNx:H abbreviated SiNx films were grown on multicrystalline silicon (mc-Si substrate by plasma enhanced chemical vapour deposition (PECVD in parallel configuration using NH3/SiH4 gas mixtures. The mc-Si wafers were taken from the same column of Si cast ingot. After the deposition process, the layers were oxidized (thermal oxidation in dry oxygen ambient environment at 950 °C to get oxide/nitride (ON structure. Secondary ion mass spectroscopy (SIMS, Rutherford backscattering spectroscopy (RBS, Auger electron spectroscopy (AES and energy dispersive X-ray analysis (EDX were employed for analyzing quantitatively the chemical composition and stoichiometry in the oxide-nitride stacked films. The effect of annealing temperature on the chemical composition of ON structure has been investigated. Some species, O, N, Si were redistributed in this structure during the thermal oxidation of SiNx. Indeed, oxygen diffused to the nitride layer into Si2O2N during dry oxidation.

  18. Ion-implantation and analysis for doped silicon slot waveguides

    Directory of Open Access Journals (Sweden)

    McCallum J. C.

    2012-10-01

    Full Text Available We have utilised ion implantation to fabricate silicon nanocrystal sensitised erbium-doped slot waveguide structures in a Si/SiO2/Si layered configuration and photoluminescence (PL and Rutherford backscattering spectrometry (RBS to analyse these structures. Slot waveguide structures in which light is confined to a nanometre-scale low-index region between two high-index regions potentially offer significant advantages for realisation of electrically-pumped Si devices with optical gain and possibly quantum optical devices. We are currently investigating an alternative pathway in which high quality thermal oxides are grown on silicon and ion implantation is used to introduce the Er and Si-ncs into the SiO2 layer. This approach provides considerable control over the Er and Si-nc concentrations and depth profiles which is important for exploring the available parameter space and developing optimised structures. RBS is well-suited to compositional analysis of these layered structures. To improve the depth sensitivity we have used a 1 MeV α beam and results indicate that a layered silicon-Er:SiO2/silicon structure has been fabricated as desired. In this paper structural results will be compared to Er photoluminescence profiles for samples processed under a range of conditions.

  19. 3D Visualization of Radar Backscattering Diagrams Based on OpenGL

    Science.gov (United States)

    Zhulina, Yulia V.

    2004-12-01

    A digital method of calculating the radar backscattering diagrams is presented. The method uses a digital model of an arbitrary scattering object in the 3D graphics package "OpenGL" and calculates the backscattered signal in the physical optics approximation. The backscattering diagram is constructed by means of rotating the object model around the radar-target line.

  20. Drivers of ASCAT C band backscatter variability in the dry snow zone of Antarctica

    NARCIS (Netherlands)

    Fraser, Alexander D.; Nigro, Melissa A.; Ligtenberg, Stefan R. M.; Legresy, Benoit; Inoue, Mana; Cassano, John J.; Munneke, Peter Kuipers; Lenaerts, Jan T. M.; Young, Neal W.; Treverrow, Adam; Van Den Broeke, Michiel; Enomot, Hiroyuki

    2016-01-01

    C band backscatter parameters contain information about the upper snowpack/firn in the dry snow zone. The wide incidence angle diversity of the Advanced Scatterometer (ASCAT) gives unprecedented characterisation of backscatter anisotropy, revealing the backscatter response to climatic forcing. The A

  1. Comparison of Ultrasound Attenuation and Backscatter Estimates in Layered Tissue-Mimicking Phantoms among Three Clinical Scanners

    Science.gov (United States)

    Nam, Kibo; Rosado-Mendez, Ivan M.; Wirtzfeld, Lauren A.; Ghoshal, Goutam; Pawlicki, Alexander D.; Madsen, Ernest L.; Lavarello, Roberto J.; Oelze, Michael L.; Zagzebski, James A.; O’Brien, William D.; Hall, Timothy J.

    2013-01-01

    Backscatter and attenuation coefficient estimates are needed in many quantitative ultrasound strategies. In clinical applications, these parameters may not be easily obtained because of variations in scattering by tissues overlying a region of interest (ROI). The goal of this study is to assess the accuracy of backscatter and attenuation estimates for regions distal to nonuniform layers of tissue-mimicking materials. In addition, this work compares results of these estimates for “layered” phantoms scanned using different clinical ultrasound machines. Two tissue-mimicking phantoms were constructed, each exhibiting depth-dependent variations in attenuation or backscatter. The phantoms were scanned with three ultrasound imaging systems, acquiring radio frequency echo data for offline analysis. The attenuation coefficient and the backscatter coefficient (BSC) for sections of the phantoms were estimated using the reference phantom method. Properties of each layer were also measured with laboratory techniques on test samples manufactured during the construction of the phantom. Estimates of the attenuation coefficient versus frequency slope, α0, using backscatter data from the different systems agreed to within 0.24 dB/cm-MHz. Bias in the α0 estimates varied with the location of the ROI. BSC estimates for phantom sections whose locations ranged from 0 to 7 cm from the transducer agreed among the different systems and with theoretical predictions, with a mean bias error of 1.01 dB over the used bandwidths. This study demonstrates that attenuation and BSCs can be accurately estimated in layered inhomogeneous media using pulse-echo data from clinical imaging systems. PMID:23160474

  2. Characteristics of CALIOP attenuated backscatter noise: implication for cloud/aerosol detection

    Directory of Open Access Journals (Sweden)

    D. L. Wu

    2010-07-01

    Full Text Available To study cloud/aerosol features in the upper troposphere and lower stratosphere (UT/LS with the NASA's A-Train sensors, a research algorithm is developed for a re-gridded CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization Level 1 (L1 backscatter dataset. This paper provides a detailed analysis of the measurement noise of this re-gridded dataset in order to compare the lidar measurements with other collocated measurements (e.g., CloudSat, Microwave Limb Sounder. The re-gridded dataset has a manageable data volume for multi-year analysis. It has a fixed (5 km horizontal resolution, and the measurement error is derived empirically from the background-corrected backscatter profile on a profile-by-profile basis. The 532-nm and 1064-nm measurement noises, determined from the data at altitudes above 19 km, are analyzed and characterized in terms of the mean (μ, standard deviation (σ, and normalized probability density function (PDF. These noises show a larger variance over landmasses and bright surfaces during day, and in regions with enhanced flux of energetic particles during night, where the instrument's ability for feature detection is slightly degraded. An increasing trend in the nighttime 1064-nm σ appears to be significant, which likely causes the increasing differences in cloud occurrence frequency between the 532-nm and 1064-nm channels. Most of the CALIOP backscatter noise distributions exhibit a Gaussian-like behavior but the nighttime 532-nm perpendicular measurements show multi-Gaussian characteristics. We apply σ – based thresholds to detect cloud/aerosol features in the UT/LS from the subset L1 data. The observed morphology is similar to that from the Level 2 (L2 05km_CLAY+05km_ALAY product, but the occurrence frequency obtained in this study is slightly lower than the L2 product due to differences in spatial averaging and detection threshold. In the case where the measurement noises of two data sets are different, the

  3. Control of coherent backscattering by breaking optical reciprocity

    CERN Document Server

    Bromberg, Y; Popoff, S M; Cao, H

    2015-01-01

    Reciprocity is a universal principle that has a profound impact on many areas of physics. A fundamental phenomenon in condensed-matter physics, optical physics and acoustics, arising from reciprocity, is the constructive interference of quantum or classical waves which propagate along time-reversed paths in disordered media, leading to, for example, weak localization and metal-insulator transition. Previous studies have shown that such coherent effects are suppressed when reciprocity is broken. Here we show that by breaking reciprocity in a controlled manner, we can tune, rather than simply suppress, these phenomena. In particular, we manipulate coherent backscattering of light, also known as weak localization. By utilizing a non-reciprocal magneto-optical effect, we control the interference between time-reversed paths inside a multimode fiber with strong mode mixing, and realize a continuous transition from the well-known peak to a dip in the backscattered intensity. Our results may open new possibilities fo...

  4. Lidar extinction-to-backscatter ratio of the ocean.

    Science.gov (United States)

    Churnside, James H; Sullivan, James M; Twardowski, Michael S

    2014-07-28

    Bio-optical models are used to develop a model of the lidar extinction-to-backscatter ratio applicable to oceanographic lidar. The model is based on chlorophyll concentration, and is expected to be valid for Case 1 waters. The limiting cases of narrow- and wide-beam lidars are presented and compared with estimates based on in situ optical measurements. Lidar measurements are also compared with the model using in situ or satellite estimates of chlorophyll concentration. A modified lidar ratio is defined, in which the properties of pure sea water are removed. This modified ratio is shown to be nearly constant for wide-beam lidar operating in low-chlorophyll waters, so accurate inversion to derive extinction and backscattering is possible under these conditions. This ratio can also be used for lidar calibration.

  5. RFID tag modification for full depth backscatter modulation

    Science.gov (United States)

    Scott, Jeffrey Wayne [Pasco, WA; Pratt, Richard M [Richland, WA

    2010-07-20

    A modulated backscatter radio frequency identification device includes a diode detector configured to selectively modulate a reply signal onto an incoming continuous wave; communications circuitry configured to provide a modulation control signal to the diode detector, the diode detector being configured to modulate the reply signal in response to be modulation control signal; and circuitry configured to increase impedance change at the diode detector which would otherwise not occur because the diode detector rectifies the incoming continuous wave while modulating the reply signal, whereby reducing the rectified signal increases modulation depth by removing the reverse bias effects on impedance changes. Methods of improving depth of modulation in a modulated backscatter radio frequency identification device are also provided.

  6. Bathymetry and Acoustic Backscatter: Northern Santa Barbara Channel, Southern California

    Science.gov (United States)

    Dartnell, Pete; Finlayson, David; Conrad, Jamie; Cochrane, Guy; Johnson, Samuel

    2010-01-01

    In the summer of 2008, as part of the California Seafloor Mapping Program (CSMP) the U.S. Geological Survey, Coastal and Marine Geology mapped a nearshore region of the northern Santa Barbara Channel in Southern California (fig 1). The CSMP is a cooperative partnership between Federal and State agencies, Universities, and Industry to create a comprehensive coastal/marine geologic and habitat basemap series to support the Marine Life Protection Act (MLPA) inititive. The program is supported by the California Ocean Protection Council and the California Coastal Conservancy. The 2008 mapping collected high resolution bathymetry and acoustic backscatter data using a bathymetric side scan system within State waters from about the 10-m isobath out over 3-nautical miles. This Open-File Report provides these data in a number of different formats, as well as a summary of the mapping mission, maps of bathymetry and backscatter, and FGDC metadata.

  7. Coherent inelastic backscattering of laser light from three isotropic atoms

    CERN Document Server

    Ketterer, Andreas; Shatokhin, Vyacheslav N

    2014-01-01

    We study the impact of double and triple scattering contributions on coherent backscattering of laser light from saturated isotropic atoms, in the helicity preserving polarization channel. Using the recently proposed diagrammatic pump-probe approach, we analytically derive single-atom spectral responses to a classical polychromatic driving field, combine them self-consistently to double and triple scattering processes, and numerically deduce the corresponding elastic and inelastic spectra, as well as the total backscattered intensities. We find that account of the triple scattering contribution leads to a faster decay of phase-coherence with increasing saturation of the atomic transition as compared to double scattering alone, and to a better agreement with the experiment on strontium atoms.

  8. On the collocation between dayside auroral activity and coherent HF radar backscatter

    Directory of Open Access Journals (Sweden)

    J. Moen

    Full Text Available The 2D morphology of coherent HF radar and optical cusp aurora has been studied for conditions of predominantly southward IMF conditions, which favours low-latitude boundary layer reconnection. Despite the variability in shape of radar cusp Doppler spectra, the spectral width criterion of > 220 m s–1 proves to be a robust cusp discriminator. For extended periods of well-developed radar backscatter echoes, the equatorward boundary of the > 220 m s–1 spectral width enhancement lines up remarkably well with the equatorward boundary of the optical cusp aurora. The spectral width boundary is however poorly determined during development and fading of radar cusp backscatter. Closer inspection of radar Doppler profile characteristics suggests that a combination of spectral width and shape may advance boundary layer identification by HF radar. For the two December days studied the onset of radar cusp backscatter occurred within pre-existing 630.0 nm cusp auroral activity and appear to be initiated by sunrise, i.e. favourable radio wave propagation conditions had to develop. Better methods are put forward for analysing optical data, and for physical interpretation of HF radar data, and for combining these data, as applied to detection, tracking, and better understanding of dayside aurora. The broader motivation of this work is to develop wider use by the scientific community, of results of these techniques, to accelerate understanding of dynamic high-latitude boundary-processes. The contributions in this work are: (1 improved techniques of analysis of observational data, yielding meaningfully enhanced accuracy for deduced cusp locations; (2 a correspondingly more pronounced validation of correlation of boundary locations derived from the observational data set; and (3 a firmer physical rationale as to why the good correlation observed should theoretically be expected.

    Key words: Ionosphere (ionospheric

  9. Surface effects on the microwave backscatter and emission of snow

    Science.gov (United States)

    Fung, A. K.; Stiles, W. H.; Ulaby, F. T.

    1980-01-01

    Measurements were performed with active and passive microwave sensors for both dry and wet snow conditions. A layer of Rayleigh scatterers with irregular surface boundaries is found to be a reasonable model for interpreting passive and active measurements in X- and Ku-bands. It was found that roughness had a significant effect on both backscatter and emission from wet snow; however, only a small effect was noted for dry snow.

  10. Valley-protected backscattering suppression in silicon photonic graphene

    CERN Document Server

    Chen, Xiao-Dong

    2016-01-01

    In this paper, we study valley degree of freedom in all dielectric silicon photonic graphene. Photonic band gap opening physics under inversion symmetry breaking is revisited by the viewpoint of nonzero valley Chern number. Bulk valley modes with opposite orbital angular momentum are unveiled by inspecting time-varying electric fields. Topological transition is well illustrated through photonic Dirac Hamiltonian. Valley dependent edge states and the associated valley-protected backscattering suppression around Z-shape bend waveguide have been demonstrated.

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

    Science.gov (United States)

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

    2016-01-01

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

  12. Reduced Brillouin backscatter in CO2 laser-target interaction

    Science.gov (United States)

    Ng, A.; Offenberger, A. A.; Karttunen, S. J.

    1981-02-01

    A substantially reduced Brillouin reflection has been found for CO2 laser-irradiated high-density gas targets. In contrast to the high reflectivity (60%) previously observed for underdense hydrogen plasma, total backscatter (stimulated plus specular) is found to peak at 30% for incident intensity 5 times 10 to the twelfth W per square centimeter and decrease thereafter to 18% at 10 to the thirteenth W per square centimeter. The ponderomotive effects are postulated to account for these observations.

  13. Relating Soil Moisture to TRMMPR Backscatter in Southern United States

    Science.gov (United States)

    Puri, S.; Stephen, H.; Ahmad, S.

    2009-12-01

    Soil Moisture is an important variable in hydrological cycle. It plays a vital role in agronomy, meteorology, and hydrology. In spite of being an important variable, soil moisture measuring stations are sparse. This is due to high cost involved in the installation of dense network of measuring stations required to map a comprehensive spatio-temporal behavior of soil moisture. Hence, there is a need to develop an alternate method to measure soil moisture. This research relates soil moisture (SM) to backscatter (σ°) obtained from Tropical Rainfall Measuring Mission Precipitation Radar (TRMMPR) and Normalized Difference Vegetation Index (NDVI) obtained from Advanced Very High Resolution Radiometer. SM data is obtained from Soil Climate Analysis Network (SCAN). σ° measurements are normalized at an incidence angle of 10° at which it has the highest sensitivity to SM. An empirical model that relates SM to normalized σ° and NDVI is developed. NDVI takes into account the different vegetation densities. The relationship between model variables is approximated to be linear. The model is applied to data from 1998 to 2008 where 75% of the data is used for calibration and the remaining 25% for validation. Figure 1 shows the comparison of observed and modeled soil moisture for a site with low vegetation. Even though the model underestimates the soil moisture content, it captures the signal well and produces peaks similar to the observed soil moisture. The model performs well with a correlation of 0.71 and root mean square error of 4.0%. The accuracy of the model depends on vegetation density. Table 1 summarizes the model performance for different vegetation densities. The model performance decreases with the increase in vegetation as the leaves in the vegetation canopy attenuate the incident microwaves which reduces the penetration depth and subsequently the sensitivity to soil moisture. This research provides a new insight into the microwave remote sensing of soil

  14. Backscatter LIDAR signal simulation applied to spacecraft LIDAR instrument design

    Science.gov (United States)

    Fochesatto, J.; Ristori, P.; Flamant, P.; Machado, M. E.; Singh, U.; Quel, E.

    2004-01-01

    In the framework of the scientific cooperation between the CEILAP laboratory (Argentina) and IPSL Institut Pierre Simon Laplace (France), devoted to the development of LIDAR techniques for Atmospheric sciences, a new area of scientific research, involving LIDARs, is starting in Argentine space technology. This new research area is under consideration at CEILAP in a joint effort with CONAE, the Argentine space agency, responsible for the development of future space missions. The LIDAR technique is necessary to improve our knowledge of meteorological, dynamic, and radiative processes in the South American region, for the whole troposphere and the lower stratosphere. To study this future mission, a simple model for the prediction of backscatter LIDAR signal from a spacecraft platform has been used to determine dimensions and detection characteristics of the space borne LIDAR instrument. The backscatter signal was retrieved from a modeled atmosphere considering its molecular density profile and taking into account different aerosols and clouds conditions. Signal-to-noise consideration, within the interval of possible dimension of the instrument parameters, allows us to constrain the telescope receiving area and to derive maximum range achievable, integration time and the final spatial and temporal resolutions of backscatter profiles.

  15. Simulation Studies of the Backscattering Signal in HSRL Technique

    CERN Document Server

    Georgakopoulou, Angelika

    2012-01-01

    The technique of High Spectral Resolution Lidar (HSRL) for atmospheric monitoring allows the determination of the aerosol to molecular ratio and can be used in UHECR Observatories using air fluorescence telescopes. By this technique a more accurate estimate of the Cherenkov radiation superimposed to the fluorescence signal can be achieved. A laboratory setup was developed to determine the backscattering coefficients using microparticles diluted in water and diffusion interfaces. In this setup we used a CW SLM laser at 532 nm and a 250 mm Newtonian telescope. Simulations of the above experimental configuration have been made using Scatlab\\c{opyright}, FINESSE\\c{opyright} 0.99.8 and MATLAB\\c{opyright} and are presented in this work. We compare the simulated 2-dimensional Fabry-Perot fringe images of the backscattering signal recorded in the CCD sensor with that of experimental ones. Additionally, we simulated the backscattering of the laser beam by the atmosphere at a height of 2000 m and we have studied the in...

  16. Investigation of phonon coherence and backscattering using silicon nanomeshes

    Science.gov (United States)

    Lee, Jaeho; Lee, Woochul; Wehmeyer, Geoff; Dhuey, Scott; Olynick, Deirdre L.; Cabrini, Stefano; Dames, Chris; Urban, Jeffrey J.; Yang, Peidong

    2017-01-01

    Phonons can display both wave-like and particle-like behaviour during thermal transport. While thermal transport in silicon nanomeshes has been previously interpreted by phonon wave effects due to interference with periodic structures, as well as phonon particle effects including backscattering, the dominant mechanism responsible for thermal conductivity reductions below classical predictions still remains unclear. Here we isolate the wave-related coherence effects by comparing periodic and aperiodic nanomeshes, and quantify the backscattering effect by comparing variable-pitch nanomeshes. We measure identical (within 6% uncertainty) thermal conductivities for periodic and aperiodic nanomeshes of the same average pitch, and reduced thermal conductivities for nanomeshes with smaller pitches. Ray tracing simulations support the measurement results. We conclude phonon coherence is unimportant for thermal transport in silicon nanomeshes with periodicities of 100 nm and higher and temperatures above 14 K, and phonon backscattering, as manifested in the classical size effect, is responsible for the thermal conductivity reduction. PMID:28051081

  17. Sentinel-1 backscatter sensitivity to vegetation dynamics at the field scale.

    Science.gov (United States)

    Vreugdenhil, Mariette; Eder, Alexander; Bauer-Marschallinger, Bernhard; Cao, Senmao; Naeimi, Vahid; Oismueller, Markus; Strauss, Peter; Wagner, Wolfgang

    2017-04-01

    four different cropfields. An in situ soil moisture network provides continuous soil moisture measurements at 31 locations within the catchment. Different polarizations and ratios thereof were calculated and compared, both spatially and temporally, to the in situ measurements of vegetation height, LAI, vegetation water content and soil moisture. Preliminary results show a clear spatial pattern in cross-polarized backscatter, which is related to different crop types. Time series analysis suggests that a ratio between cross- and co-polarized backscatter is affected by both vegetation water content and vegetation structure. This presentation will provide a comprehensive assessment of Sentinel-1's capability for monitoring of vegetation over croplands, using in situ reference data obtained over a full growing season.

  18. Amorphous Carbon Gold Nanocomposite Thin Films: Structural and Spectro-ellipsometric Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Montiel-Gonzalez, Z., E-mail: zeuzmontiel@hotmail.com [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito exterior s/n, Ciudad Universitaria, Coyoacan 04510, Mexico D.F (Mexico); Rodil, S.E.; Muhl, S. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito exterior s/n, Ciudad Universitaria, Coyoacan 04510, Mexico D.F (Mexico); Mendoza-Galvan, A. [Centro de Investigacion y de Estudios Avanzados del Instituto Politecnico Nacional, Unidad Queretaro, 76010 Queretaro, Queretaro (Mexico); Rodriguez-Fernandez, L. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito de la Investigacion Cientifica, Ciudad Universitaria, 04510, Mexico D.F (Mexico)

    2011-07-01

    Spectroscopic Ellipsometry was used to determine the optical and structural properties of amorphous carbon:gold nanocomposite thin films deposited by dc magnetron co-sputtering at different deposition power. The incorporation of gold as small particles distributed in the amorphous carbon matrix was confirmed by X-ray Diffraction, Rutherford Backscattering measurements and High Resolution Transmission Electron Microscopy. Based on these results, an optical model for the films was developed using the Maxwell-Garnett effective medium with the Drude-Lorentz model representing the optical response of gold and the Tauc-Lorentz model for the amorphous carbon. The gold volume fraction and particle size obtained from the fitting processes were comparable to those from the physical characterization. The analysis of the ellipsometric spectra for all the samples showed strong changes in the optical properties of the carbon films as a consequence of the gold incorporation. These changes were correlated to the structural modification observed by Raman Spectroscopy, which indicated a clustering of the sp{sup 2} phase with a subsequent decrease in the optical gap. Finally, measurements of Reflection and Transmission Spectroscopy were carried out and Transmission Electron Microscopy images were obtained in order to support the ellipsometric model results.

  19. Timepix and FitPix detection system for RBS/C materials analysis

    CERN Document Server

    David-Bosne, Eric; Wahl, Ulrich

    This thesis reports the implementation of a Timepix position sensitive detector in a ion beam facility with a 0.5 mm collimated beam of 2MeV 1H$^{+}$ and 4He$^{+}$ for use in Rutherford Back-scattering Spectrometry channeling (RBS/C). A complete description is given of the methodology used for energy calibration, RBS data analysis and simulation with the FLUX Monte Carlo simulation program. Energy calibration was performed with internal test pulses and resulting resolution and accuracy were verified in two ways. The first time using a triple alpha source with the isotopes $^{239}$Pu, $^{241}$Am and $^{244}$Cm and secondly using a RBS spectrum of a thin film sample of Au/SiO$_{2}$/C. Setup characterization for channeling measurements was performed using single crystals of Si, 6H$^{-}$SiC and SrTiO$_{3}$. An energy resolution of 47.2 keV at 1862 keV for He$^{+}$ and an angular resolution of 0.11 (standard deviation) was achieved. Count rates as high as 2kHz were achieved with a frame rate of 15 frames/s. Higher...

  20. Quantitative analysis of amorphous indium zinc oxide thin films synthesized by Combinatorial Pulsed Laser Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Axente, E.; Socol, G.; Luculescu, C.R.; Craciun, V. [National Institute for Lasers, Plasma and Radiation Physics, Laser-Surface-Plasma Interactions Laboratory, Lasers Department, Magurele-Bucharest (Romania); Beldjilali, S.A. [LP3, CNRS-Aix-Marseille University, Marseille (France); LPPMCA, USTOMB-Universite des Sciences et de la Technologie d' Oran, BP 1505, Oran (Algeria); Mercadier, L.; Hermann, J. [LP3, CNRS-Aix-Marseille University, Marseille (France); Trinca, L.M.; Galca, A.C. [National Institute of Materials Physics, Laboratory of Multifunctional Materials and Structures, Magurele-Bucharest (Romania); Pantelica, D.; Ionescu, P. [National Institute of Physics and Nuclear Engineering Horia Hulubei, Magurele-Bucharest (Romania); Becherescu, N. [Apel Laser, Bucharest (Romania)

    2014-10-15

    The use of amorphous and transparent oxides is a key for the development of new thin film transistors and displays. Recently, indium zinc oxide (IZO) was shown to exhibit high transparency in the visible range, low resistivity, and high mobility. Since the properties and the cost of these films depend on the In/(In + Zn) values, the measurement of this ratio is paramount for future developments and applications. We report on accurate analysis of the elemental composition of IZO thin films synthesized using a Combinatorial Pulsed Laser Deposition technique. The monitoring of the thin films elemental composition by Laser-Induced Breakdown Spectroscopy was chosen in view of further in situ and real-time technological developments and process control during IZO fabrication. Our analytical approach is based on plasma modeling, the recorded spectra being then compared to the spectral radiance computed for plasmas in local thermal equilibrium. The cation fractions measured were compared to values obtained by complementary measurements using energy dispersive X-ray spectroscopy and Rutherford backscattering spectrometry. Spectroscopic ellipsometry assisted the scientific discussion. A good agreement between methods was found, independently of the relative fraction of indium and zinc that varied from about 65 to 90 and 35 to 10 at%, respectively, and the measurement uncertainties associated to each analytical method. (orig.)

  1. Generation of tens-of-MeV photons by compton backscatter from laser-plasma-accelerated GeV electrons

    Science.gov (United States)

    Shaw, J. M.; Bernstein, A. C.; Hannasch, A.; LaBerge, M.; Chang, Y.-Y.; Weichman, K.; Welch, J.; Zgadzaj, R.; Henderson, W.; Tsai, H.-E.; Fazel, N.; Wang, X.; Wagner, C.; Donovan, M.; Dyer, G.; Gaul, E.; Gordon, J.; Martinez, M.; Spinks, M.; Toncian, T.; Ditmire, T.; Downer, M. C.

    2017-03-01

    Previous work has demonstrated the use of a plasma mirror (PM), after a laser-plasma accelerator (LPA), for generating Compton γ-rays by retro-reflecting the spent laser pulse into the just-accelerated electrons. Here, we investigate the use of a PM to stimulate Compton backscatter (CBS) by retro-reflecting a spent pulse from the Texas Petawatt (TPW) laser after it has driven a cm-scale, GeV LPA. A comparative analysis between the electron and CBS pointing and divergence reveals strong agreement, from shot-to-shot, suggesting a reliable, non-invasive extension for GeV-beam metrology. Our observations confirm the self-aligning PM method is scalable to GeV LPAs, while also suggesting a technique with unique advantages and a robustness that can potentially be exploited for investigations of nonlinear Compton backscatter from ultralow divergence, GeV electrons using the Texas Petawatt Laser.

  2. Development of ΔE-E telescope ERDA with 40 MeV 35Cl7+ beam at MALT in the University of Tokyo optimized for analysis of metal oxynitride thin films

    Science.gov (United States)

    Harayama, I.; Nagashima, K.; Hirose, Y.; Matsuzaki, H.; Sekiba, D.

    2016-10-01

    We have developed a compact ΔE-E telescope elastic recoil detection analysis (ERDA) system, for the first time at Micro Analysis Laboratory, Tandem Accelerator (MALT) in the University of Tokyo, which consists of a gas ionization chamber and solid state detector (SSD) for the quantitative analysis of light elements. The gas ionization chamber is designed to identify the recoils of O and N from metal oxynitrides thin films irradiated with 40 MeV 35Cl7+. The length of the electrodes along the beam direction is 50 mm optimized to sufficiently separate energy loss of O and N recoils in P10 gas at 6.0 × 103 Pa. The performance of the gas ionization chamber was examined by comparing the ERDA results on the SrTaO2N thin films with semi-empirical simulation and the chemical compositions previously determined by nuclear reaction analysis (NRA) and Rutherford backscattering spectrometry (RBS). We also confirmed availability of the gas ionization chamber for identifying not only the recoils of O and N but also those of lithium, carbon and fluorine.

  3. Multibeam volume acoustic backscatter imagery and reverberation measurements in the northeastern Gulf of Mexico

    Science.gov (United States)

    Gallaudet, Timothy C.; deMoustier, Christian P.

    2002-08-01

    Multibeam volume acoustic backscatter imagery and reverberation measurements are derived from data collected in 200-m-deep waters in the northeastern Gulf of Mexico, with the Toroidal Volume Search Sonar (TVSS), a 68-kHz cylindrical sonar operated by the U.S. Navy's Coastal System Station. The TVSS's 360-degree vertical imaging plane allows simultaneous identification of multiple volume scattering sources and their discrimination from backscatter at the sea surface or the seafloor. This imaging capability is used to construct a three-dimensional representation of a pelagic fish school near the bottom. Scattering layers imaged in the mixed layer and upper thermocline are attributed to assemblages of epipelagic zooplankton. The fine scale patchiness of these scatterers is assessed with the two-dimensional variance spectra of vertical volume scattering strength images in the upper and middle water column. Mean volume reverberation levels exhibit a vertical directionality which is attributed to the volume scattering layers. Boundary echo sidelobe interference and reverberation is shown to be the major limitation in obtaining bioacoustic data with the TVSS. Because net tow and trawl samples were not collected with the acoustic data, the analysis presented is based upon comparison to previous biologic surveys in the northeastern Gulf of Mexico and reference to the bioacoustic literature. copyright 2002 Acoustical Society of America.

  4. Performance of Dynamically Simulated Reference Patterns for Cross-Correlation Electron Backscatter Diffraction.

    Science.gov (United States)

    Jackson, Brian E; Christensen, Jordan J; Singh, Saransh; De Graef, Marc; Fullwood, David T; Homer, Eric R; Wagoner, Robert H

    2016-08-01

    High-resolution (or "cross-correlation") electron backscatter diffraction analysis (HR-EBSD) utilizes cross-correlation techniques to determine relative orientation and distortion of an experimental electron backscatter diffraction pattern with respect to a reference pattern. The integrity of absolute strain and tetragonality measurements of a standard Si/SiGe material have previously been analyzed using reference patterns produced by kinematical simulation. Although the results were promising, the noise levels were significantly higher for kinematically produced patterns, compared with real patterns taken from the Si region of the sample. This paper applies HR-EBSD techniques to analyze lattice distortion in an Si/SiGe sample, using recently developed dynamically simulated patterns. The results are compared with those from experimental and kinematically simulated patterns. Dynamical patterns provide significantly more precision than kinematical patterns. Dynamical patterns also provide better estimates of tetragonality at low levels of distortion relative to the reference pattern; kinematical patterns can perform better at large values of relative tetragonality due to the ability to rapidly generate patterns relating to a distorted lattice. A library of dynamically generated patterns with different lattice parameters might be used to achieve a similar advantage. The convergence of the cross-correlation approach is also assessed for the different reference pattern types.

  5. Coherent Backscatter Opposition Effect from Scratches on Solid Surfaces

    Science.gov (United States)

    Hapke, B. W.; Piatek, J. L.; Nelson, R. M.; Smythe, W. D.; Hale, A. S.

    2003-05-01

    Shepard and Arvidson [1] discovered that the solid surfaces of rocks exhibit an opposition effect. We have measured the phase curve of a natural surface of a piece of solid basalt between 0.05 and 5 degrees in circularly polarized light using the JPL long arm goniometer and confirmed that it has an opposition effect. The circular polarization ratio (CPR) increased with decreasing phase angle, consistent with a coherent backscatter opposition effect (CBOE) Recent laboratory investigations of the CBOE in planetary regolith analogs [2,3,4] have revealed that the width of the peak is remarkably insensitive to particle size, in strong contrast to theoretical expectations. We have hypothesized that one of the reasons for this might be that multiple scattering between irregularities, such as scratches, on the surfaces of a particle could cause coherent backscatter, in addition to scattering between particles. To test this hypothesis we ground the surface of a piece of plate glass with 5 micrometer abrasive and measured its phase curve. As the phase angle decreases, the intensity increases and the CPR decreases, consistent with specular reflection. However, near zero phase there is a nonlinear rise about 2 degrees wide superimposed on the linear specular peak accompanied by an increase in CPR, showing that coherent backscatter is occuring. A piece of commercial diffusing glass exhibited the same phenomena. These results support our hypothesis and also provide a possible explanation for the observations of opposition effects from the solid surfaces of rocks. This research was supported by a grant from NASA's PGG Program References cited: [1] Shepard and Arvidson, Icarus, 141, 172-178 (1999). [2] Nelson et al, Icarus, 147, 545-558 (2000). [3] Nelson et al, Planet. Space Sci., 50, 849-856 (2002). [4] Piatek et al, Abstract, DPS Conference (2003).

  6. Evaluation of a compact sensor for backscattering and absorption.

    Science.gov (United States)

    Bogdan, Alina Gainusa; Boss, Emmanuel S

    2011-07-20

    Seawater inherent optical properties (IOPs) are key parameters in a wide range of applications in environmental studies and oceanographic research. In particular, the absorption coefficient (a) is the typical IOP used to obtain the concentration of chlorophyll-a in the water-a critical parameter in biological oceanography studies and the backscattering coefficient (b(b)) is used as a measure of turbidity. In this study, we test a novel instrument concept designed to obtain both the absorption and backscattering coefficients. The instrument would emit a collimated monochromatic light beam into the water retrieving the backscattered light intensity as a function of distance from the center of illumination. We use Monte Carlo modeling of light propagation to create an inversion algorithm that translates the signal from such an instrument into values of a and b(b). Our results, based on simulations spanning the bulk of natural values of seawater IOP combinations, indicate that a 6.2 cm diameter instrument with a radial resolution of 1 cm would be capable of predicting b(b) within less than 13.4% relative difference and a within less than 57% relative difference (for 90% of the inverted a values, the relative errors fall below 29.7%). Additionally, these errors could be further reduced by constraining the inversion algorithm with information from concurrent measurements of other IOPs. Such a compact and relatively simple device could have multiple applications for in situ optical measurements, including a and b(b) retrievals from instrumentation mounted on autonomous underwater vehicles. Furthermore, the same methodology could possibly be used for an out-of-water sensor. © 2011 Optical Society of America

  7. Quantifying Fish Backscattering using SONAR Instrument and Kirchhoff Ray Mode (KRM) Model

    Science.gov (United States)

    Manik, Henry M.

    2016-08-01

    Sonar instrument was used to study backscattering from tuna fish. Extraction of target strength, incidence angle, and frequency dependence of the backscattered signal for individual scatterer was important for biological information. For this purpose, acoustic measurement of fish backscatter was conducted in the laboratory. Characteristics and general trends of the target strength of fish with special reference to tuna fish were investigated by using a Kirchhoff Ray Mode (KRM) model. Backscattering strength were calculated for the KRM having typical morphological and physical parameters of actual fish. Those backscattering amplitudes were shown as frequency, body length, backscattering patterns, the density and sound speed dependences, and orientation dependence. These results were compared with experimentally measured target strength data and good agreement was found. Measurement and model showed the target strength from the fish are depend on the presence of swimbladder. Target Strength increase with increasing the frequency and fish length.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-11-01

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

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

    Directory of Open Access Journals (Sweden)

    C. A. Brau

    2004-02-01

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

  10. A Backscatter-Suppressed Beta Spectrometer for Neutron Decay Studies

    CERN Document Server

    Wietfeldt, F E; Anderman, R; Bateman, F B; Dewey, M S; Komives, A; Thompson, A K; Balashov, S; Mostovoy, Y; Mostovoy, Yu.

    2004-01-01

    We describe a beta electron spectrometer for use in an upcoming experiment that will measure the beta-antineutrino correlation coefficient (a-coefficient) in neutron beta decay. Electron energy is measured by a thick plastic scintillator detector. A conical array of plastic scintillator veto detectors is used to suppress events where the electron backscattered. A Monte Carlo simulation of this device in the configuration of the a-coefficient experiment is presented. The design, construction, and testing of a full-scale prototype device is described. We discuss the performance of this spectrometer with respect to its suitability for the experiment.

  11. DUNBID, the Delft University neutron backscattering imaging detector

    Energy Technology Data Exchange (ETDEWEB)

    Bom, V.R. [Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands)]. E-mail: vb@iri.tudelft.nl; Eijk, C.W.E. van [Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Ali, M.A. [Atomic Energy Authority, Nuclear Research Center, Reactor and Neutron Physics Department, P.O. Box 13759, Abu Zabal, Cairo (Egypt)

    2005-12-01

    In the search for low-metallic land mines, the neutron backscattering technique may be applied if the soil is sufficiently dry. An advantage of this method is the speed of detection: the scanning speed may be made comparable to that of a metal detector. A two-dimensional position sensitive detector is tested to obtain an image of the back scattered thermal neutron radiation. Results of experiments using a radionuclide neutron source are presented. The on-mine to no-mine signal ratio can be improved by the application of a window on the neutron time-of-flight. Results using a pulsed neutron generator are also presented.

  12. Combined backscatter and transmission method for nuclear density gauge

    Directory of Open Access Journals (Sweden)

    Golgoun Seyed Mohammad

    2015-01-01

    Full Text Available Nowadays, the use of nuclear density gauges, due to the ability to work in harsh industrial environments, is very common. In this study, to reduce error related to the ρ of continuous measuring density, the combination of backscatter and transmission are used simultaneously. For this reason, a 137Cs source for Compton scattering dominance and two detectors are simulated by MCNP4C code for measuring the density of 3 materials. Important advantages of this combined radiometric gauge are diminished influence of μ and therefore improving linear regression.

  13. Bulk media assay using backscattered Pu-Be neutrons

    CERN Document Server

    Csikai, J

    1999-01-01

    Spectral yields of elastically backscattered Pu-Be neutrons measured for graphite, water, polyethylene, liquid nitrogen, paraffin oil, SiO sub 2 , Al, Fe, and Pb slabs show a definite correlation with the energy dependence of the elastic scattering cross sections, sigma sub E sub L (E sub n). The C, N and O can be identified by the different structures in their sigma sub E sub L (E sub n) functions. The integrated spectral yields versus thickness exhibit saturation for each sample. The interrogated volume is limited by the presence of hydrogen in the sample. (author)

  14. Photoneutron production with the Laser-Compton backscattered photons

    Energy Technology Data Exchange (ETDEWEB)

    Toyokawa, Hiroyuki; Ohgaki, Hideaki; Sugiyama, Suguru; Mikado, Tomohisa; Yamada, Kawakatsu; Suzuki, Ryoichi; Ohdaira, Toshiyuki; Sei, Norihiro; Chiwaki, Mitsukuni [Electrotechnical Laboratory, Tsukuba, Ibaraki (Japan)

    1999-03-01

    A method to produce quasi-monoenergetic photoneutrons for detector calibration was examined. The photoneutrons were produced with a photo-induced neutron emission of a {sup 9}Be using the Laser-Compton backscattered photons. Because the photon energy is continuously tunable, neutrons with various energies are obtained. Yield of the neutrons was measured with a liquid scintillation detector at the photon energies from 1651 keV to 3019 keV. Neutron yield at around the threshold energy for the {sup 9}Be ({gamma}, n) reaction was measured by changing the photon energy in a 10 keV step. (author)

  15. HAB detection based on absorption and backscattering properties of phytoplankton

    Science.gov (United States)

    Lei, Hui; Pan, Delu; Bai, Yan; Chen, Xiaoyan; Zhou, Yan; Zhu, Qiankun

    2011-11-01

    The coastal area of East China Sea (ECS) suffers from the harmful algal blooms (HAB) frequently every year in the warm season. The most common causative phytoplankton algal species of HAB in the ECS in recent years are Prorocentrum donghaiense (dinoflagellates), Karenia mikimotoi (dinoflagellates which could produce hemolytic and ichthyotoxins) and Skeletonema costatum (diatom). The discrimination between the dinoflagellates and diatom HAB through ocean color remote sensing approach can add the knowledge of HAB events in ECS and help to the precaution. A series of in-situ measurement consisted of absorption coefficient, total scattering and particulate backscattering coefficient was conducted in the southern coast of Zhejiang Province in May 2009, and the estuary of Changjiang River in August 2009 and December 2010, which encountered two HAB events and a moderate bloom. The Inherent Optical Properties (IOPs) of the bloom waters have significant difference between phytoplankton species in absorption and backscattering properties. The chlorophyll a specific absorption coefficient (a*phy(λ)) for the bloom patches (chlorophyll a concentration >6mg m-3) differ greatly from the adjacent normal seawater, with the a*phy(λ) of bloom water lower than 0.03 m2 mg-1 while the a*phy(λ) of the adjacent normal seawater is much higher (even up to 0.06 m2 mg-1). Meanwhile, the backscattering coefficients at 6 wavebands (420, 442, 470, 510, 590 and 700nm) are also remarkably lower for bloom waters ( 0.02 m-1). The backscattering coefficient ratio (Rbp(λ)) is much lower for diatom bloom waters than for dinoflagellates types (0.01079 vs. 0.01227). A discrimination model based on IOPs is established, and several typical dinoflagellates and diatom bloom events including Prorocentrum donghaiense, Karenia mikimotoi and Skeletonema costatum in the ECS are picked out for testing with the MODIS-L2 and L3 ocean color remote sensing products from NASA website. The result proves that the

  16. 3D Visualization of Radar Backscattering Diagrams Based on OpenGL

    Directory of Open Access Journals (Sweden)

    Yulia V. Zhulina

    2004-03-01

    Full Text Available A digital method of calculating the radar backscattering diagrams is presented. The method uses a digital model of an arbitrary scattering object in the 3D graphics package “OpenGL” and calculates the backscattered signal in the physical optics approximation. The backscattering diagram is constructed by means of rotating the object model around the radar-target line.

  17. Monte Carlo Simulation of the Coaxial Electrons Backscattering from Thin Films

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By using the Monte Carlo method, we simulated the trajectories of coaxial backscattering electrons corresponding to a new type of scanning electron microscope. From the calculated results, we obtain a universal expression, which describes with good accuracy the backscattering coefficient versus film thickness under all conditions used. By measuring the coaxial backscattering coefficient and using this universal formula, the thickness of thin films can be determined if the composition is known.

  18. The effect of wind-generated bubbles on sea-surface backscatter

    OpenAIRE

    Vossen, R.; Ainslie, M.A.

    2009-01-01

    Predictions of sea-surface back-scattering strength are needed for sonar performance modelling. Such predictions are hampered by two problems. First, measurements of surface back-scattering are not available at small grazing angles. These are of special interest to low-frequency active sonar since they mainly contribute to long range propagation. Second, existing theoretical models based on a bubble-free interface underestimate the surface back-scattering strength at larger grazing angles. We...

  19. VIBA-Lab 3.0: Computer program for simulation and semi-quantitative analysis of PIXE and RBS spectra and 2D elemental maps

    Energy Technology Data Exchange (ETDEWEB)

    Orlić, Ivica; Mekterović, Darko [Department of Physics, University of Rijeka, Radmile Matejčić 2, 51000 Rijeka (Croatia); Mekterović, Igor [Faculty of Electrical Engineering and Computing, University of Zagreb (Croatia); Ivošević, Tatjana [Faculty of Engineering, University of Rijeka, Vukovarska 58, HR-51000 Rijeka (Croatia)

    2015-11-15

    VIBA-Lab is a computer program originally developed by the author and co-workers at the National University of Singapore (NUS) as an interactive software package for simulation of Particle Induced X-ray Emission and Rutherford Backscattering Spectra. The original program is redeveloped to a VIBA-Lab 3.0 in which the user can perform semi-quantitative analysis by comparing simulated and measured spectra as well as simulate 2D elemental maps for a given 3D sample composition. The latest version has a new and more versatile user interface. It also has the latest data set of fundamental parameters such as Coster–Kronig transition rates, fluorescence yields, mass absorption coefficients and ionization cross sections for K and L lines in a wider energy range than the original program. Our short-term plan is to introduce routine for quantitative analysis for multiple PIXE and XRF excitations. VIBA-Lab is an excellent teaching tool for students and researchers in using PIXE and RBS techniques. At the same time the program helps when planning an experiment and when optimizing experimental parameters such as incident ions, their energy, detector specifications, filters, geometry, etc. By “running” a virtual experiment the user can test various scenarios until the optimal PIXE and BS spectra are obtained and in this way save a lot of expensive machine time.

  20. Scanning transmission ion microscopy mass measurements for quantitative trace element analysis within biological samples and validation using atomic force microscopy thickness measurements

    Science.gov (United States)

    Devès, Guillaume; Cohen-Bouhacina, Touria; Ortega, Richard

    2004-10-01

    We used the nuclear microprobe techniques, micro-PIXE (particle-induced X-ray emission), micro-RBS (Rutherford backscattering spectrometry) and scanning transmission ion microscopy (STIM) in order to perform the characterization of trace element content and spatial distribution within biological samples (dehydrated cultured cells, tissues). The normalization of PIXE results was usually expressed in terms of sample dry mass as determined by micro-RBS recorded simultaneously to micro-PIXE. However, the main limit of RBS mass measurement is the sample mass loss occurring during irradiation and which could be up to 30% of the initial sample mass. We present here a new methodology for PIXE normalization and quantitative analysis of trace element within biological samples based on dry mass measurement performed by mean of STIM. The validation of STIM cell mass measurements was obtained in comparison with AFM sample thickness measurements. Results indicated the reliability of STIM mass measurement performed on biological samples and suggested that STIM should be performed for PIXE normalization. Further information deriving from direct confrontation of AFM and STIM analysis could as well be obtained, like in situ measurements of cell specific gravity within cells compartment (nucleolus and cytoplasm).