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Sample records for scattering studies showed

  1. Small-angle scattering studies show distinct conformations of calmodulin in its complexes with two peptides based on the regulatory domain of the catalytic subunit of phosphorylase kinase

    International Nuclear Information System (INIS)

    Trewhella, J.; Blumenthal, D.K.; Rokop, S.E.; Seeger, P.A.

    1990-01-01

    Small-angle X-ray and neutron scattering have been used to study the solution structures of calmodulin complexed with synthetic peptides corresponding to residues 342-366 and 301-326, designated PhK5 and PhK13, respectively, in the regulatory domain of the catalytic subunit of skeletal muscle phosphorylase kinase. The scattering data show that binding of PhK5 to calmodulin induces a dramatic contraction of calmodulin, similar to that previously observed when calmodulin is complexed with the calmodulin-binding domain peptide from rabbit skeletal muscle myosin light chain kinase. In contrast, calmodulin remains extended upon binding PhK13. In the presence of both peptides, calmodulin also remains extended. Apparently, the presence of PhK13 inhibits calmodulin from undergoing the PhK5-induced contraction. These data indicate that there is a fundamentally different type of calmodulin-target enzyme interaction in the case of the catalytic subunit of phosphorylase kinase compared with that for myosin light chain kinase

  2. Light scattering studies at UNICAMP

    International Nuclear Information System (INIS)

    Luzzi, R.; Cerdeira, H.A.; Salzberg, J.; Vasconcellos, A.R.; Frota Pessoa, S.; Reis, F.G. dos; Ferrari, C.A.; Algarte, C.A.S.; Tenan, M.A.

    1975-01-01

    Current theoretical studies on light scattering spectroscopy at UNICAMP is presented briefly, such as: inelastic scattering of radiation from a solid state plasma; resonant Ramman scattering; high excitation effects; saturated semiconductors and glasses

  3. Recent development in magnetic neutron scattering studies

    International Nuclear Information System (INIS)

    Endoh, Yasuo

    1993-01-01

    Neutron scattering results contain many new concepts in modern magnetism. We review here the most recent neutron magnetic scattering studies from so called '214' copper oxide lamellar materials, because a number of important developments in magnetism are condensed in this novel subject. We show that neutron scattering has played crucial role in our understanding of modern magnetism. (author)

  4. Neutron scattering studies of modulated magnetic structures

    Energy Technology Data Exchange (ETDEWEB)

    Aagaard Soerensen, Steen

    1999-08-01

    This report describes investigations of the magnetic systems DyFe{sub 4}Al{sub 8} and MnSi by neutron scattering and in the former case also by X-ray magnetic resonant scattering. The report is divided into three parts: An introduction to the technique of neutron scattering with special emphasis on the relation between the scattering cross section and the correlations between the scattering entities of the sample. The theoretical framework of neutron scattering experiments using polarized beam technique is outlined. The second part describes neutron and X-ray scattering investigation of the magnetic structures of DyFe{sub 4}Al{sub 8}. The Fe sublattice of the compound order at 180 K in a cycloidal structure in the basal plane of the bct crystal structure. At 25 K the ordering of the Dy sublattice shows up. By the element specific technique of X-ray resonant magnetic scattering, the basal plane cycloidal structure was also found for the Dy sublattice. The work also includes neutron scattering studies of DyFe{sub 4}Al{sub 8} in magnetic fields up to 5 T applied along a <110> direction. The modulated structure at the Dy sublattice is quenched by a field lower than 1 T, whereas modulation is present at the Fe sublattice even when the 5 T field is applied. In the third part of the report, results from three small angle neutron experiments on MnSi are presented. At ambient pressure, a MnSi is known to form a helical spin density wave at temperature below 29 K. The application of 4.5 kbar pressure intended as hydrostatic decreased the Neel temperature to 25 K and changed the orientation of the modulation vector. To understand this reorientation within the current theoretical framework, anisotropic deformation of the sample crystal must be present. The development of magnetic critical scattering with an isotropic distribution of intensity has been studied at a level of detail higher than that of work found in the literature. Finally the potential of a novel polarization

  5. A neutron scattering study of DCN

    International Nuclear Information System (INIS)

    Mackenzie, G.A.; Pawley, G.S.

    1979-01-01

    Phonons in deuterium cyanide have been measured by neutron coherent inelastic scattering. The main subject of study was the transverse acoustic mode in the (110) direction polarised along (110) which is associated with the first-order structural phase transition at 160 K. Measurements have shown that the frequency decreases by about 25% between about 225 and 160 K as the transition temperature is approached. The other acoustic modes observable in the a*b* scattering plane have been measured and show no anomalous temperature dependence. Optic modes were unobservable because of the small size of the single-crystal sample which gave insufficient scattered intensity. Apart from the 'soft' mode, the measured frequencies are in good agreement with lattice dynamics calculations. (author)

  6. Neutron scattering studies in the actinide region

    International Nuclear Information System (INIS)

    Kegel, G.H.R.; Egan, J.J.

    1993-09-01

    This report discusses the following topics: Prompt fission neutron energy spectra for 235 U and 239 Pu; Two-parameter measurement of nuclear lifetimes; ''Black'' neutron detector; Data reduction techniques for neutron scattering experiments; Inelastic neutron scattering studies in 197 Au; Elastic and inelastic scattering studies in 239 Pu; and neutron induced defects in silicon dioxide MOS structures

  7. A didactic experiment showing the Compton scattering by means of a clinical gamma camera.

    Science.gov (United States)

    Amato, Ernesto; Auditore, Lucrezia; Campennì, Alfredo; Minutoli, Fabio; Cucinotta, Mariapaola; Sindoni, Alessandro; Baldari, Sergio

    2017-06-01

    We describe a didactic approach aimed to explain the effect of Compton scattering in nuclear medicine imaging, exploiting the comparison of a didactic experiment with a gamma camera with the outcomes from a Monte Carlo simulation of the same experimental apparatus. We employed a 99m Tc source emitting 140.5keV photons, collimated in the upper direction through two pinholes, shielded by 6mm of lead. An aluminium cylinder was placed on the source at 50mm of distance. The energy of the scattered photons was measured on the spectra acquired by the gamma camera. We observed that the gamma ray energy measured at each step of rotation gradually decreased from the characteristic energy of 140.5keV at 0° to 102.5keV at 120°. A comparison between the obtained data and the expected results from the Compton formula and from the Monte Carlo simulation revealed a full agreement within the experimental error (relative errors between -0.56% and 1.19%), given by the energy resolution of the gamma camera. Also the electron rest mass has been evaluated satisfactorily. The experiment was found useful in explaining nuclear medicine residents the phenomenology of the Compton scattering and its importance in the nuclear medicine imaging, and it can be profitably proposed during the training of medical physics residents as well. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  8. Neutron scattering studies of solid electrolytes

    International Nuclear Information System (INIS)

    Shapiro, S.M.

    1976-01-01

    The role which neutron scattering can play in determining the nature of the disorder and the conducting mechanism in the solid electrolytes is discussed. First, some of the general formalism for elastic and inelastic neutron scattering is reviewed, and the quantities which can be measured are pointed out. Then the application of neutron scattering to the studies of three different problems is examined; the anion disorder in the fluorite system, the dynamical behavior in beta-alumina, and the cation diffusion in αAgI are discussed. 8 figures

  9. Neutron scattering shows a droplet of oleic acid at the center of the BAMLET complex.

    Science.gov (United States)

    Rath, Emma M; Duff, Anthony P; Gilbert, Elliot P; Doherty, Greg; Knott, Robert B; Church, W Bret

    2017-07-01

    The anti-cancer complex, Bovine Alpha-lactalbumin Made LEthal to Tumors (BAMLET), has intriguing broad-spectrum anti-cancer activity. Although aspects of BAMLET's anti-cancer mechanism are still not known, it is understood that it involves the oleic acid or oleate component of BAMLET being preferentially released into cancer cell membranes leading to increased membrane permeability and lysis. The structure of the protein component of BAMLET has previously been elucidated by small angle X-ray scattering (SAXS) to be partially unfolded and dramatically enlarged. However, the structure of the oleic acid component of BAMLET and its disposition with respect to the protein component was not revealed as oleic acid has the same X-ray scattering length density (SLD) as water. Employing the difference in the neutron SLDs of hydrogen and deuterium, we carried out solvent contrast variation small angle neutron scattering (SANS) experiments of hydrogenated BAMLET in deuterated water buffers, to reveal the size, shape, and disposition of the oleic acid component of BAMLET. Our resulting analysis and models generated from SANS and SAXS data indicate that oleic acid forms a spherical droplet of oil incompletely encapsulated by the partially unfolded protein component. This model provides insight into the anti-cancer mechanism of this cache of lipid. The model also reveals a protein component "tail" not associated with the oleic acid component that is able to interact with the tail of other BAMLET molecules, providing a plausible explanation of how BAMLET readily forms aggregates. Proteins 2017; 85:1371-1378. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  10. Neutron Scattering studies of magnetic molecular magnets

    International Nuclear Information System (INIS)

    Chaboussant, G.

    2009-01-01

    This work deals with inelastic neutron scattering studies of magnetic molecular magnets and focuses on their magnetic properties at low temperature and low energies. Several molecular magnets (Mn 12 , V 15 , Ni 12 , Mn 4 , etc.) are reviewed. Inelastic neutron scattering is shown to be a perfectly suited spectroscopy tool to -a) probe magnetic energy levels in such systems and -b) provide key information to understand the quantum tunnel effect of the magnetization in molecular spin clusters. (author)

  11. Neutron scattering studies in the actinide region

    International Nuclear Information System (INIS)

    Beghian, L.E.; Kegel, G.H.R.

    1991-08-01

    During the report period we have investigated the following areas: Neutron elastic and inelastic scattering measurements on 14 N, 181 Ta, 232 Th, 238 U and 239 Pu; Prompt fission spectra for 232 Th, 235 U, 238 U and 239 Pu; Theoretical studies of neutron scattering; Neutron filters; New detector systems; and Upgrading of neutron target assembly, data acquisition system, and accelerator/beam-line apparatus

  12. Analytic scattering kernels for neutron thermalization studies

    International Nuclear Information System (INIS)

    Sears, V.F.

    1990-01-01

    Current plans call for the inclusion of a liquid hydrogen or deuterium cold source in the NRU replacement vessel. This report is part of an ongoing study of neutron thermalization in such a cold source. Here, we develop a simple analytical model for the scattering kernel of monatomic and diatomic liquids. We also present the results of extensive numerical calculations based on this model for liquid hydrogen, liquid deuterium, and mixtures of the two. These calculations demonstrate the dependence of the scattering kernel on the incident and scattered-neutron energies, the behavior near rotational thresholds, the dependence on the centre-of-mass pair correlations, the dependence on the ortho concentration, and the dependence on the deuterium concentration in H 2 /D 2 mixtures. The total scattering cross sections are also calculated and compared with available experimental results

  13. Innovative scattering analysis shows that hydrophobic disordered proteins are expanded in water

    Energy Technology Data Exchange (ETDEWEB)

    Riback, Joshua A.; Bowman, Micayla A.; Zmyslowski, Adam M.; Knoverek, Catherine R.; Jumper, John M.; Hinshaw, James R.; Kaye, Emily B.; Freed, Karl F.; Clark, Patricia L.; Sosnick, Tobin R.

    2017-10-12

    A substantial fraction of the proteome is intrinsically disordered, and even well-folded proteins adopt non-native geometries during synthesis, folding, transport, and turnover. Characterization of intrinsically disordered proteins (IDPs) is challenging, in part because of a lack of accurate physical models and the difficulty of interpreting experimental results. We have developed a general method to extract the dimensions and solvent quality (self-interactions) of IDPs from a single small-angle x-ray scattering measurement. We applied this procedure to a variety of IDPs and found that even IDPs with low net charge and high hydrophobicity remain highly expanded in water, contrary to the general expectation that protein-like sequences collapse in water. Our results suggest that the unfolded state of most foldable sequences is expanded; we conjecture that this property was selected by evolution to minimize misfolding and aggregation.

  14. Alpha resonant scattering for astrophysical reaction studies

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, H.; Kahl, D.; Nakao, T. [Center for Nuclear Study (CNS), University of Tokyo, RIKEN campus, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Wakabayashi, Y.; Kubano, S. [The Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Hashimoto, T. [Research Center for Nuclear Physics (RCNP), Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Hayakawa, S. [Istituto Nazionale Fisica Nucleare - Laboratori Nazionali del Sud (INFN-LNS), Via S. Sofia 62, 95125 Catania (Italy); Kawabata, T. [Department of Physics, Kyoto University, Kita-Shirakawa, Kyoto 606-8502 (Japan); Iwasa, N. [Department of Physics, Tohoku University, Aoba, Sendai, Miyagi 980-8578 (Japan); Teranishi, T. [Department of Physics, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581 (Japan); Kwon, Y. K. [Institute for Basic Science, 70, Yuseong-daero 1689-gil, Yuseong-gu, Daejeon 305-811 (Korea, Republic of); Binh, D. N. [30 MeV Cyclotron Center, Tran Hung Dao Hospital, Hoan Kiem District, Hanoi (Viet Nam); Khiem, L. H.; Duy, N. G. [Institute of Physics, Vietnam Academy of Science and Technology, 18 Hong Quoc Viet, Nghia do, Hanoi (Viet Nam)

    2014-05-02

    Several alpha-induced astrophysical reactions have been studied at CRIB (CNS Radioactive Ion Beam separator), which is a low-energy RI beam separator at Center for Nuclear Study (CNS) of the University of Tokyo. One of the methods to study them is the α resonant scattering using the thick-target method in inverse kinematics. Among the recent studies at CRIB, the measurement of {sup 7}Be+α resonant scattering is discussed. Based on the result of the experiment, we evaluated the contributions of high-lying resonances for the {sup 7}Be(α,γ) reaction, and proposed a new cluster band in {sup 11}C.

  15. Alpha resonant scattering for astrophysical reaction studies

    International Nuclear Information System (INIS)

    Yamaguchi, H.; Kahl, D.; Nakao, T.; Wakabayashi, Y.; Kubano, S.; Hashimoto, T.; Hayakawa, S.; Kawabata, T.; Iwasa, N.; Teranishi, T.; Kwon, Y. K.; Binh, D. N.; Khiem, L. H.; Duy, N. G.

    2014-01-01

    Several alpha-induced astrophysical reactions have been studied at CRIB (CNS Radioactive Ion Beam separator), which is a low-energy RI beam separator at Center for Nuclear Study (CNS) of the University of Tokyo. One of the methods to study them is the α resonant scattering using the thick-target method in inverse kinematics. Among the recent studies at CRIB, the measurement of 7 Be+α resonant scattering is discussed. Based on the result of the experiment, we evaluated the contributions of high-lying resonances for the 7 Be(α,γ) reaction, and proposed a new cluster band in 11 C

  16. Neutron scattering study of dilute supercritical solutions

    International Nuclear Information System (INIS)

    Cochran, H.D.; Wignall, G.D.; Shah, V.M.; Londono, J.D.; Bienkowski, P.R.

    1994-01-01

    Dilute solutions in supercritical solvents exhibit interesting microstructures that are related to their dramatic macroscopic behavior. In typical attractive solutions, solutes are believed to be surrounded by clusters of solvent molecules, and solute molecules are believed to congregate in the vicinity of one another. Repulsive solutions, on the other hand, exhibit a local region of reduced solvent density around the solute with solute-solute congregation. Such microstructures influence solubility, partial molar volume, reaction kinetics, and many other properties. We have undertaken to observe these interesting microstructures directly by neutron scattering experiments on dilute noble gas systems including Ar. The three partial structure factors for such systems and the corresponding pair correlation functions can be determined by using the isotope substitution technique. The systems studied are uniquely suited for our objectives because of the large coherent neutron scattering length of the isotope 36 Ar and because of the accurate potential energy functions that are available for use in molecular simulations and theoretical calculations to be compared with the scattering results. We will describe our experiment, the unique apparatus we have built for it, and the neutron scattering results from our initial allocations of beam time. We will also describe planned scattering experiments to follow those with noble gases, including study of long-chain molecules in supercritical solvents. Such studies will involve hydrocarbon mixtures with and without deuteration to provide contrast

  17. Studies in small angle scattering techniques

    International Nuclear Information System (INIS)

    Moellenbach, K.

    1980-03-01

    Small angle scattering of neutrons, X-rays and γ-rays are found among the spectroscopic methods developed in the recent years. Although these techniques differ from each other in many respects, e.g. radiation sources and technical equipment needed, their power to resolve physical phenomena and areas of application can be discussed in a general scheme. Selected examples are given illustrating the use of specific technical methods. Jahn-Teller driven structural phase transitions in Rare Earth zircons were studied with neutron scattering as well as small angle γ-ray diffraction. The study of neutron scattering from formations of magnetic domains in the Ising ferromagnet LiTbF 4 is a second example. Both these examples represent more than experimental test cases since the theoretical interpretations of the data obtained are discussed as well. As a last example the use of small angle scattering methods for the study of molecular biological samples is discussed. In particular the experimental procedures used in connection with scattering from aqueous solutions of proteins and protein complexes are given. (Auth.)

  18. Light scattering studies of solids and atomic vapors

    International Nuclear Information System (INIS)

    Chiang, T.C.

    1978-09-01

    The general technique of light scattering and luminescence was used to study the properties of a number of material systems. First, multi-phonon resonant Raman scattering up to four phonons in GaSe and one- and two-phonon resonant Raman scattering in the mixed GaS/sub x/Se/sub 1-x/ crystals with x 2 is reported. The result is used to determine the position of the direct gap of HfS 2 . Third, the first observation of the π-polarized one-magnon luminescence sideband of the 4 T/sub lg/ ( 4 G) → 6 A/sub lg/( 6 S) excitonic transition in antiferromagnetic MnF 2 is presented. An effective temperature of the crystal is deduced from the simultaneously observed anti-Stokes sideband emission. Multi-magnon ( 2 , KMnF 2 , and RbMnF 3 using pulsed excitation and detection. A simple model based on two-ion local exchange is proposed to explain the results qualitatively. Fourth, the first observation of two-magnon resonant Raman scattering in MnF 2 around the magnon sidebands is reported. A simple theoretical description explains the experimental observations. Fifth, a detailed theory of exciton-exciton interaction in MnF 2 is developed to explain and to predict the experimental results on two-exciton absorption, high level excitation, and exciton--exciton scattering. Sixth, Brillouin scattering was used to obtain the five independent elastic constants of the layered compound GaSe. The results show clear elastic anisotropy of the crystal. Resonant Brillouin scattering near the absorption edge was also studied, but no resonant enhancement was found. Seventh, two-photon parametric scattering in sodium vapor was studied. Phase matching angles and scattering cross sections are calculated for a given set of experimental conditions

  19. Nucleon structure study by virtual compton scattering

    International Nuclear Information System (INIS)

    Berthot, J.; Bertin, P.Y.; Breton, V.; Fonvielle, H.; Hyde-Wright, C.; Quemener, G.; Ravel, O.; Braghieri, A.; Pedroni, P.; Boeglin, W.U.; Boehm, R.; Distler, M.; Edelhoff, R.; Friedrich, J.; Geiges, R.; Jennewein, P.; Kahrau, M.; Korn, M.; Kramer, H.; Krygier, K.W.; Kunde, V.; Liesenfeld, A.; Merle, K.; Neuhausen, R.; Offermann, E.A.J.M.; Pospischil, T.; Rosner, G.; Sauer, P.; Schmieden, H.; Schardt, S.; Tamas, G.; Wagner, A.; Walcher, T.; Wolf, S.

    1995-01-01

    We propose to study nucleon structure by Virtual Compton Scattering using the reaction p(e,e'p)γ with the MAMI facility. We will detect the scattered electron and the recoil proton in coincidence in the high resolution spectrometers of the hall A1. Compton events will be separated from the other channels (principally π 0 production) by missing-mass reconstruction. We plan to investigate this reaction near threshold. Our goal is to measure new electromagnetic observables which generalize the usual magnetic and electric polarizabilities. (authors). 9 refs., 18 figs., 7 tabs

  20. NEUTRON-SCATTERING STUDY OF DCN

    DEFF Research Database (Denmark)

    Mackenzie, Gordon A.; Pawley, G. S.

    1979-01-01

    Phonons in deuterium cyanide have been measured by neutron coherent inelastic scattering. The main subject of study was the transverse acoustic mode in the (110) direction polarised along (110) which is associated with the first-order structural phase transition at 160K. Measurements have shown...

  1. Instrumentation for millisecond-resolution scattering studies

    International Nuclear Information System (INIS)

    Stephenson, G.B.; Ludwig, K.F. Jr.; Jordan-Sweet, J.L.; Brauer, S.; Mainville, J.; Yang, Y.S.; Sutton, M.

    1989-01-01

    Time-resolved x-ray scattering studies of phase transition kinetics have been carried out using the wide-bandpass monochromator and fast linear position-sensitive detector system at the IBM/MIT beamline X-20C at the National Synchrotron Light Source (NSLS). We report here on the instrumentation that has been developed for these studies, and in particular on the methods used to measure, change, and control sample temperature with millisecond resolution

  2. Resonant inelastic x-ray scattering studies of elementary excitations

    NARCIS (Netherlands)

    Ament, Lucas Johannes Peter (Luuk)

    2010-01-01

    Resonant Inelastic X-ray Scattering (RIXS) is an X-ray in, X-ray out technique that enables one to study the dispersion of excitations in solids. In this thesis, we investigated how various elementary excitations of transition metal oxides show up in RIXS spectra.

  3. Study of nuclei by electron scattering

    International Nuclear Information System (INIS)

    Torizuka, Yoshiharu; Saito, Teijiro; Ito, Kohei; Terasawa, Tatsuo; Hosoyama, Kenji.

    1974-01-01

    It is urgently required to clarify the physical meaning of the quasi-elastic scattering associated with the background, in order to develop rapidly the study of giant resonance. The experimental works performed in the present term aimed at the synthetic understanding of both giant resonance and quasi-elastic scattering, and presented the possibility of the separability of giant resonance from quasi-elastic scattering. The object of this experiment was to measure higher order multi-pole moment of 51 V by using relatively high energy electron beam. Targets of chemically pure 51 V had thickness of 68.2 or 100.5 mg/cm 2 . The measurement was made at the position where scattering angle was 155 0 . The state of M7 can be well explained by the model with (fsub(7/2)) 3 coordination. This may be because the nuclei with stretched configuration such as 51 V do not have any contribution of orbital motion, but have the contribution of eigen magnetic moment to the highest multiplicity. States of M3 and M5 are a little complicated. Since in the experimental equipment used, the contribution of charge distribution was so large, that it was difficult to make the precision measurement of M3 and M5. In 51 V, however, it can be considered that M3 and M5 decreased by the contribution of 2Psub(3/2) and 1fsub(5/2). On the other hand, there is no contribution from these energy states to M7. (Tai, I.)

  4. Neutron Inelastic Scattering Study of Liquid Argon

    Energy Technology Data Exchange (ETDEWEB)

    Skoeld, K; Rowe, J M; Ostrowski, G [Solid State Science Div., Argonne National Laboratory, Argonne, Illinois (US); Randolph, P D [Nuclear Technology Div., Idaho Nuclear Corporation, Idaho Falls, Idaho (US)

    1972-02-15

    The inelastic scattering functions for liquid argon have been measured at 85.2 K. The coherent scattering function was obtained from a measurement on pure A-36 and the incoherent function was derived from the result obtained from the A-36 sample and the result obtained from a mixture of A-36 and A-40 for which the scattering is predominantly incoherent. The data, which are presented as smooth scattering functions at constant values of the wave vector transfer in the range 10 - 44/nm, are corrected for multiple scattering contributions and for resolution effects. Such corrections are shown to be essential in the derivation of reliable scattering functions from neutron scattering data. The incoherent data are compared to recent molecular dynamics results and the mean square displacement as a function of time is derived. The coherent data are compared to molecular dynamics results and also, briefly, to some recent theoretical models

  5. Wines: water inelastic neutron scattering experimental study

    International Nuclear Information System (INIS)

    Risch, P.; Ait Abderrahim, H.; D'hondt, P.; Malabu, E.

    1997-01-01

    An intercomparison of calculated fast neutron flux (E > 1 MeV) traverse through a very thick water zone obtained using both S N , (DORT) and Monte-Carlo (TRIPOLI and MCBEND) codes in combination with different cross-sections libraries (based on ENDF/B-III, IV, V and VI), showed small discrepancies either between S N , and Monte-Carlo results or even between S N , or Monte-Carlo results when we consider different cross-sections libraries except for S N , calculation when using P 0 , cross-sections. In order to validate our calculations we looked for experimental data. Unfortunately no experiment, dedicated for the fast neutron transport in large thickness of water, was found in the literature. Therefore SCK-CEN and EDF decided to launch the WINES experiment which is dedicated to study this phenomenon. WINES sands for Water Inelastic Neutron scattering Experimental Study. The aim of this experiment is to provide-experimental data for validation of neutron transport codes and nuclear cross-sections libraries used for LWR surveillance dosimetry analysis. The experimental device is made of 1 m 3 cubic plexiglass container filled with demineralized water. At one face of this cube, a 235 U neutron fission source system is screwed. The source device is made of a 235 U (93 % weight enriched) 18.55 x 16 cm 2 plate cladded with aluminium which is inserted in neutron beam emerging from the graphite gas-cooled BR1 reactor. Fission chambers ( 238 U(n,f), 232 Th(n,f), 237 Np(n,f) and 235 U(n,f)) are used to measure the flux traverses on the central axis of the water cube perpendicular to the fission sources. In this paper we will compare the experimental data to the calculated results using the S N , transport code DORT with the P 3 , ELXSIR library, based on ENDF/B-V, and the P 7 -BUGLE-93 library, based on ENDF/B-VI as well as the Monte-Carlo transport code TRIPOLI with a cross-section library based on ENDF/B IV and ENDF/B-VI. (authors)

  6. Study of material science by neutron scattering

    International Nuclear Information System (INIS)

    Kim, H.J.; Yoon, B.K.; Cheon, B.C.; Lee, C.Y.; Kim, C.S.

    1980-01-01

    To develop accurate methods of texture measurement in metallic materials by neutron diffraction, (100),(200),(111) and (310) pole figures have been measured for the oriented silicon steel sheet, and currently study of correction methods for neutron absorption and extinction effects are in progress. For quantitative analysis of texture of polycrystalline material with a cubic structure, a software has been developed to calculate inverse pole figures for arbitrary direction specified in the speciman as well as pole figures for arbitrary chosen crystallographic planes from three experimental pole figures. This work is to be extended for the calculation of three dimensional orientation distribution function and for the evaluation of errors in the quantitative analysis of texture. Work is also for the study of N-H...O hydrogen bond in amino acid by observing molecular motions using neutron inelastic scattering. Measurement of neutron inelastic scattering spectrum of L-Serine is completed at 100 0 K and over the energy transfer range of 20-150 meV. (KAERI INIS Section)

  7. Multiple small-angle neutron scattering studies of anisotropic materials

    CERN Document Server

    Allen, A J; Long, G G; Ilavsky, J

    2002-01-01

    Building on previous work that considered spherical scatterers and randomly oriented spheroidal scatterers, we describe a multiple small-angle neutron scattering (MSANS) analysis for nonrandomly oriented spheroids. We illustrate this with studies of the multi-component void morphologies found in plasma-spray thermal barrier coatings. (orig.)

  8. SCATTER

    International Nuclear Information System (INIS)

    Broome, J.

    1965-11-01

    The programme SCATTER is a KDF9 programme in the Egtran dialect of Fortran to generate normalized angular distributions for elastically scattered neutrons from data input as the coefficients of a Legendre polynomial series, or from differential cross-section data. Also, differential cross-section data may be analysed to produce Legendre polynomial coefficients. Output on cards punched in the format of the U.K. A. E. A. Nuclear Data Library is optional. (author)

  9. Neutron scattering studies of the actinides

    International Nuclear Information System (INIS)

    Lander, G.H.

    1979-01-01

    The electronic structure of actinide materials presents a unique example of the interplay between localized and band electrons. Together with a variety of other techniques, especially magnetization and the Mossbauer effect, neutron studies have helped us to understand the systematics of many actinide compounds that order magnetically. A direct consequence of the localization of 5f electrons is the spin-orbit coupling and subsequent spin-lattice interaction that often leads to strongly anisotropic behavior. The unusual phase transition in UO 2 , for example, arises from interactions between quadrupole moments. On the other hand, in the monopnictides and monochalcogenides, the anisotropy is more difficult to understand, but probably involves an interaction between actinide and anion wave functions. A variety of neutron experiments, including form-factor studies, critical scattering and measurements of the elementary excitations have now been performed, and the conceptual picture emerging from these studies will be discussed

  10. Neutron scattering studies on frustrated magnets

    International Nuclear Information System (INIS)

    Arima, Taka-hisa

    2013-01-01

    A lot of frustrated magnetic systems exhibit a nontrivial magnetic order, such as long-wavelength modulation, noncollinear, or noncoplanar order. The nontrivial order may pave the way for the novel magnetic function of matter. Neutron studies are necessary to determine the magnetic structures in the frustrated magnetic systems. In particular, spin-polarized neutron scattering is a useful technique for the investigation of the novel physical properties relevant to the nontrivial spin arrangement. Here some neutron studies on a multiferroic perovskite manganese oxide system are demonstrated as a typical case. The frustrated magnetic systems may also a playground of novel types of local magnetic excitations, which behave like particles in contrast to the magnetic waves. It is becoming a good challenge to study such particle-type magnetic excitations relevant to the magnetic frustration. (author)

  11. Studying coherent scattering in the CP stars atmospheres

    Science.gov (United States)

    Fišák, J.; Kubát, J.; Krtička, J.

    2018-01-01

    Chemically peculiar stars form a very interesting class of stars which frequently show variability. The variability is probably caused by the uneven surface distribution of chemical elements. Some elements are overabundant and some elements are underabundant compared to the solar chemical composition. In the case of chemically overabundant composition some of the rare photon-atom processes can be more important than in the atmospheres of stars with solar chemical composition. We study the importance of Rayleigh scattering by helium.

  12. High energy gravitational scattering: a numerical study

    CERN Document Server

    Marchesini, Giuseppe

    2008-01-01

    The S-matrix in gravitational high energy scattering is computed from the region of large impact parameters b down to the regime where classical gravitational collapse is expected to occur. By solving the equation of an effective action introduced by Amati, Ciafaloni and Veneziano we find that the perturbative expansion around the leading eikonal result diverges at a critical value signalling the onset of a new regime. We then discuss the main features of our explicitly unitary S-matrix down to the Schwarzschild's radius R=2G s^(1/2), where it diverges at a critical value b ~ 2.22 R of the impact parameter. The nature of the singularity is studied with particular attention to the scaling behaviour of various observables at the transition. The numerical approach is validated by reproducing the known exact solution in the axially symmetric case to high accuracy.

  13. Neutron scattering studies of Mn12-acetate

    International Nuclear Information System (INIS)

    Robinson, R.A.

    2000-01-01

    Full text: The S=10 magnetic molecule Mn 12 -acetate, which crystallises into a tetragonal crystal structure, has attracted substantial recent attention by virtue of its low temperature bulk magnetic properties, which give evidence for resonant quantum tunnelling of the magnetisation. We report a full neutron crystal structure including positions of all protons/deuterons, including the solvated water and acetic acid, a polarised-neutron study of the real space magnetisation, which confirms a simple magnetic-structure model for the molecule, albeit with reduced Mn moments, and inelastic neutron scattering data containing both the excitations within the 21-fold degenerate S=10 manifold, and those from S=10 to the S=9 manifolds. Both manifolds are split by uniaxial magnetic anisotropy, and we report coefficients for 2nd and 4th-order terms in the magnetic Hamiltonian

  14. Systematic study on nuclear resonant scattering

    International Nuclear Information System (INIS)

    Suarez, A.A.; Freitas, M.L.

    1974-01-01

    New resonant scattering effect of thermal neutron capture gamma rays from Ti and Fe on Sb, Cu, Se and Ce target were observed. These results together with those published by other authors are summarized and discussed in terms of a possible systematic search for new resonant scattering effects

  15. Study of Compton broadening due to electron-photon scattering

    Directory of Open Access Journals (Sweden)

    Srinivasa Rao M.

    2010-01-01

    Full Text Available We have investigated the effects of Compton broadening due to electron-photon scattering in hot stellar atmospheres. A purely electron-photon scattering media is assumed to have plane parallel geometry with an input radia­tion field localized on one side of the slab. The method is based on the discrete space theory of radiative transfer for the intensity of emitted radiation. The solution is developed to study the importance of scattering of radiation by free electrons in high temperature stellar atmospheres which produces a brodening and shift in spectral lines because of the Compton effect and the Doppler effect arising from mass and thermal motions of scattering electrons. It is noticed that the Comptonized spectrum depends on three parameters: the optical depth of the medium, the temperature of the thermal electrons and the viewing angle. We also showed that the Compton effect produces red shift and asymmetry in the line. These two effects increase as the optical depth increases. It is also noticed that the emergent specific intensities become completely asymmetric for higher optical depths.

  16. Study of Compton Broadening Due to Electron-Photon Scattering

    Directory of Open Access Journals (Sweden)

    Srinivasa Rao, M.

    2010-06-01

    Full Text Available We have investigated the effects of Compton broadening due to electron-photon scattering in hot stellar atmospheres. A purely electron-photon scattering media is assumed to have plane parallel geometry with an input radiation field localized on one side of the slab. The method is based on the discrete space theory of radiative transfer for the intensity of emitted radiation.The solution is developed to study the importance of scattering of radiation by free electrons in high temperature stellar atmospheres which produces a brodening and shift in spectral lines because of the Compton effect and the Doppler effect arising from mass and thermal motions of scattering electrons.It is noticed that the Comptonized spectrum depends on three parameters: the optical depth of the medium, the temperature of the thermal electrons and the viewing angle.We also showed that the Compton effect produces red shift and asymmetry in the line. These two effects increase as the optical depth increases. It is also noticed that the emergent specific intensities become completely asymmetric for higher optical depths.

  17. Study on the Light Scattering from Random Rough Surfaces by Kirrhoff Approximation

    Directory of Open Access Journals (Sweden)

    Keding Yan

    2014-07-01

    Full Text Available In order to study the space distribution characteristics of light scattering from random rough surfaces, the linear filtering method is used to generate a series of Gaussian randomly rough surfaces, and the Kirchhoff Approximation is used to calculate the scattered light intensity distribution from random metal and dielectric rough surfaces. The three characteristics of the scattered light intensity distribution peak, the intensity distribution width and the position of peak are reviewed. Numerical calculation results show that significant differences between scattering characteristics of metal surfaces and the dielectric surfaces exist. The light scattering characteristics are jointly influenced by the slope distribution and reflectance of surface element. The scattered light intensity distribution is affected by common influence of surface local slope distribution and surface local reflectivity. The results can provide a basis theory for the research to lidar target surface scattering characteristics.

  18. Incoherent scatter studies of upper atmosphere dynamics and coding technique

    International Nuclear Information System (INIS)

    Haeggstroem, Ingemar.

    1990-09-01

    Observations by the EISCAT incoherent scatter radar are used to study the dynamics of the auroral upper atmosphere. The study describes some effects of the strong plasma convection occurring at these latitudes and a new coding technique for incoherent scatter radars. A technique to determine the thermospheric neutral wind from incoherent scatter measurements is described. Simultaneous Fabry-Perot interferometer measurements of the wind are compared with those derived from the radar data. F-region electron density depletions in the afternoon/evening sector of the auroral zone, identified as the main ionospheric trough, are investigated. In a statistical study, based on wide latitude scanning experiment made at solar minimum, the trough appearance at a given latitude is compared to the geomagnetic index K p , and an empirical model predicting the latitude of the trough is proposed. Detailed studies, using different experiment modes, show that the equatorward edge of the auroral oval is co-located of up to 1 degree poleward of the trough minimum, which in turn is co-located with the peak convective electric field, with its boundary 1 degree - 2 degree equatorward of the trough minimum. It is shown that the F-region ion composition changes from pure 0 + to molecular ion dominated (NO + /O 2 + ) as the trough moves into the region probed by the radar. In a special case, where a geomagnetic sudden impulse caused an expansion of the plasma convection pattern, the equatorward trough progression is studied together with ionosonde measurements. A new coding technique for incoherent scatter radar measurement is introduced and described. The method, called alternating codes, provides significantly more accurate estimates of the plasma parameters than can be obtained by frequency commutated multipulse measurements. Simple explanations of the method are given as well as a precise definition. Two examples of application of the alternating codes are presented, showing the high

  19. Nonlinear scattering in hard tissue studied with ultrashort laser pulses

    International Nuclear Information System (INIS)

    Eichler, J.; Kim, B.M.

    2002-01-01

    The back-scattered spectrum of ultrashort laser pulses (800 nm, 0.2 ps) was studied in human dental and other hard tissues in vitro below the ablation threshold. Frequency doubled radiation (SHG), frequency tripled radiation and two-photon fluorescence were detected. The relative yield for these processes was measured for various pulse energies. The dependence of the SHG signal on probe thickness was determined in forward and back scattering geometry. SHG is sensitive to linear polarization of the incident laser radiation. SHG in human teeth was studied in vitro showing larger signals in dentin than in cementum and enamel. In carious areas no SHG signal could be detected. Possible applications of higher harmonic radiation for diagnostics and microscopy are discussed. (orig.)

  20. Neutron scattering studies of biological molecules suggest

    Indian Academy of Sciences (India)

    tions of temperature, pressure or solvent environment for survival. ... scale that depends on the scattering vector range and energy resolution of the in- .... the structures) are good indicators of global evolutionary adaptation mechanisms.

  1. Raman scattering study of filled skutterudite compounds

    International Nuclear Information System (INIS)

    Ogita, N; Kojima, R; Hasegawa, T; Takasu, Y; Udagawa, M; Kondo, T; Takeda, N; Ikeno, T; Ishikawa, K; Sugawara, H; Kikuchi, D; Sato, H; Sekine, C; Shirotani, I

    2007-01-01

    Raman scattering of skutterudite compounds RT 4 X 12 (R=La, Ce, Pr, Nd, Sm and Yb, T=Fe, Ru and Os, X=P and Sb) have been measured. All first-order Raman active phonons are observed and are assigned as the pnicogen vibrations. At the low energy region, the second-order phonons, due to the vibration of the rare earth ions with a flat phonon dispersion, are observed in the spectra of RRu 4 P 12 (R=La and Sm) and ROs 4 Sb 12 (R=La, Ce, Pr, Nd, and Sm). The appearance of the second-order phonons in the spectra is caused by an anharmonic vibrations of rare earth ions in large cage space and a large density of state due to the flat phonon dispersion. However, in spite of the similar cage space, the 2nd-order phonons are hardly observed for RFe 4 Sb 12 and RRu 4 Sb 12 . Thus, these results suggest that the dynamics of the rare earth ion is closely related to not only the cage size but also the electronic state due to the transition metals. Raman spectra of PrRu 4 P 12 show the drastic spectral change due to the metal-insulator transition. The phonon spectra and crystal field excitations due to the structural change have been assigned above and below the transition temperature

  2. Neutron-scattering studies of chromatin

    International Nuclear Information System (INIS)

    Bradbury, E.M.; Baldwin, J.P.; Carpenter, B.G.; Hjelm, R.P.; Hancock, R.; Ibel, K.

    1976-01-01

    It is clear that a knowledge of the basic molecular structure of chromatin is a prerequisite for any progress toward an understanding of chromosome organization. With a two-component system, protein and nucleic acid, neutrons have a particularly powerful application to studies of the spatial arrangements of these components because of the ability, by contrast matching with H 2 O-D 2 O mixtures, to obtain neutron-scattering data on the individual components. With this approach it has been shown that the neutron diffraction of chromatin is consistent with a ''beads on a string'' model in which the bead consists of a protein core with DNA coiled on the outside. However, because chromatin is a gel and gives limited structural data, confirmation of such a model requires extension of the neutron studies by deuteration of specific chromatin components and the isolation of chromatin subunits. Although these studies are not complete, the neutron results so far obtained support the subunit model described above

  3. Small-angle neutron scattering technique in liquid crystal studies

    International Nuclear Information System (INIS)

    Shahidan Radiman

    2005-01-01

    The following topics discussed: general principles of SAS (Small-angle Neutron Scattering), liquid crystals, nanoparticle templating on liquid crystals, examples of SAS results, prospects of this studies

  4. Crystal defect studies using x-ray diffuse scattering

    International Nuclear Information System (INIS)

    Larson, B.C.

    1980-01-01

    Microscopic lattice defects such as point (single atom) defects, dislocation loops, and solute precipitates are characterized by local electronic density changes at the defect sites and by distortions of the lattice structure surrounding the defects. The effect of these interruptions of the crystal lattice on the scattering of x-rays is considered in this paper, and examples are presented of the use of the diffuse scattering to study the defects. X-ray studies of self-interstitials in electron irradiated aluminum and copper are discussed in terms of the identification of the interstitial configuration. Methods for detecting the onset of point defect aggregation into dislocation loops are considered and new techniques for the determination of separate size distributions for vacancy loops and interstitial loops are presented. Direct comparisons of dislocation loop measurements by x-rays with existing electron microscopy studies of dislocation loops indicate agreement for larger size loops, but x-ray measurements report higher concentrations in the smaller loop range. Methods for distinguishing between loops and three-dimensional precipitates are discussed and possibilities for detailed studies considered. A comparison of dislocation loop size distributions obtained from integral diffuse scattering measurements with those from TEM show a discrepancy in the smaller sizes similar to that described above

  5. Crystal defect studies using x-ray diffuse scattering

    Energy Technology Data Exchange (ETDEWEB)

    Larson, B.C.

    1980-01-01

    Microscopic lattice defects such as point (single atom) defects, dislocation loops, and solute precipitates are characterized by local electronic density changes at the defect sites and by distortions of the lattice structure surrounding the defects. The effect of these interruptions of the crystal lattice on the scattering of x-rays is considered in this paper, and examples are presented of the use of the diffuse scattering to study the defects. X-ray studies of self-interstitials in electron irradiated aluminum and copper are discussed in terms of the identification of the interstitial configuration. Methods for detecting the onset of point defect aggregation into dislocation loops are considered and new techniques for the determination of separate size distributions for vacancy loops and interstitial loops are presented. Direct comparisons of dislocation loop measurements by x-rays with existing electron microscopy studies of dislocation loops indicate agreement for larger size loops, but x-ray measurements report higher concentrations in the smaller loop range. Methods for distinguishing between loops and three-dimensional precipitates are discussed and possibilities for detailed studies considered. A comparison of dislocation loop size distributions obtained from integral diffuse scattering measurements with those from TEM show a discrepancy in the smaller sizes similar to that described above.

  6. Diffusion of water adsorbed in hydrotalcite: neutron scattering Study

    Energy Technology Data Exchange (ETDEWEB)

    Mitra, S [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai (India); Pramanik, A [Unilever Research India, Bangalore 500 066 (India); Chakrabarty, D [Godrej Sara Lee Limited, Research and Development Centre, Mumbai 400 079 (India); Juranyi, F [Laboratory for Neutron Scattering, ETHZ and PSI, CH-5232 Villigen PSI (Switzerland); Gautam, S [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai (India); Mukhopadhyay, R [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai (India)

    2007-12-15

    Layered double hydroxides (LDH) are a class of ionic lamellar solids with positively charged layers of two kinds of metallic cations and exchangeable hydrated anions. Quasi-elastic neutron scattering (QENS) measurements are performed in this type of LDH structured hydrated hydrotalcite sample to study the dynamical behaviour of the water in geometric confinement within the layers. Dynamical parameters correspond to the confined water molecules revealed that depending on the amount of excess water present, behaves differently and approaches bulk values at high concentration. Both translational and rotational dynamical parameters showed that at very low concentration of excess water, water molecules are attached to the surfaces and show the confinement effect.

  7. Neutron scattering study of yttrium iron garnet

    Science.gov (United States)

    Shamoto, Shin-ichi; Ito, Takashi U.; Onishi, Hiroaki; Yamauchi, Hiroki; Inamura, Yasuhiro; Matsuura, Masato; Akatsu, Mitsuhiro; Kodama, Katsuaki; Nakao, Akiko; Moyoshi, Taketo; Munakata, Koji; Ohhara, Takashi; Nakamura, Mitsutaka; Ohira-Kawamura, Seiko; Nemoto, Yuichi; Shibata, Kaoru

    2018-02-01

    The nuclear and magnetic structure and full magnon dispersions of yttrium iron garnet Y3Fe5O12 have been studied using neutron scattering. The refined nuclear structure is distorted to a trigonal space group of R 3 ¯ . The highest-energy dispersion extends up to 86 meV. The observed dispersions are reproduced by a simple model with three nearest-neighbor-exchange integrals between 16 a (octahedral) and 24 d (tetrahedral) sites, Ja a, Ja d, and Jd d, which are estimated to be 0.00 ±0.05 , -2.90 ±0.07 , and -0.35 ±0.08 meV, respectively. The lowest-energy dispersion below 14 meV exhibits a quadratic dispersion as expected from ferromagnetic magnons. The imaginary part of q -integrated dynamical spin susceptibility χ″(E ) exhibits a square-root energy dependence at low energies. The magnon density of state is estimated from χ″(E ) obtained on an absolute scale. The value is consistent with the single chirality mode for the magnon branch expected theoretically.

  8. Experimental studies of the critical scattering of neutrons for large scattering vectors

    International Nuclear Information System (INIS)

    Ciszewski, R.

    1972-01-01

    The most recent results concerned with the critical scattering of neutrons are reviewed. The emphasis is on the so-called thermal shift, that is the shift of the main maximum in the intensity of critically scattered neutrons with temperature changes. Four theories of this phenomenon are described and their shortcomings are shown. It has been concluded that the situation is involved at present and needs further theoretical and experimental study. (S.B.)

  9. Development of new methods for studying nanostructures using neutron scattering

    International Nuclear Information System (INIS)

    Pynn, Roger

    2016-01-01

    The goal of this project was to develop improved instrumentation for studying the microscopic structures of materials using neutron scattering. Neutron scattering has a number of advantages for studying material structure but suffers from the well-known disadvantage that neutrons' ability to resolve structural details is usually limited by the strength of available neutron sources. We aimed to overcome this disadvantage using a new experimental technique, called Spin Echo Scattering Angle Encoding (SESAME) that makes use of the neutron's magnetism. Our goal was to show that this innovation will allow the country to make better use of the significant investment it has recently made in a new neutron source at Oak Ridge National Laboratory (ORNL) and will lead to increases in scientific knowledge that contribute to the Nation's technological infrastructure and ability to develop advanced materials and technologies. We were successful in demonstrating the technical effectiveness of the new method and established a baseline of knowledge that has allowed ORNL to start a project to implement the method on one of its neutron beam lines.

  10. Development of new methods for studying nanostructures using neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Pynn, Roger [Indiana Univ., Bloomington, IN (United States)

    2016-03-18

    The goal of this project was to develop improved instrumentation for studying the microscopic structures of materials using neutron scattering. Neutron scattering has a number of advantages for studying material structure but suffers from the well-known disadvantage that neutrons’ ability to resolve structural details is usually limited by the strength of available neutron sources. We aimed to overcome this disadvantage using a new experimental technique, called Spin Echo Scattering Angle Encoding (SESAME) that makes use of the neutron’s magnetism. Our goal was to show that this innovation will allow the country to make better use of the significant investment it has recently made in a new neutron source at Oak Ridge National Laboratory (ORNL) and will lead to increases in scientific knowledge that contribute to the Nation’s technological infrastructure and ability to develop advanced materials and technologies. We were successful in demonstrating the technical effectiveness of the new method and established a baseline of knowledge that has allowed ORNL to start a project to implement the method on one of its neutron beam lines.

  11. Neutrons scattering studies in the actinide region

    International Nuclear Information System (INIS)

    Kegel, G.H.R.; Egan, J.J.

    1992-09-01

    During the report period were investigated the following areas: prompt fission neutron energy spectra measurements; neutron elastic and inelastic scattering from 239 Pu; neutron scattering in 181 Ta and 197 Au; response of a 235 U fission chamber near reaction thresholds; two-parameter data acquisition system; ''black'' neutron detector; investigation of neutron-induced defects in silicon dioxide; and multiple scattering corrections. Four Ph.D. dissertations and one M.S. thesis were completed during the report period. Publications consisted of three journal articles, four conference papers in proceedings, and eleven abstracts of presentations at scientific meetings. There are currently four Ph.D. and one M.S. candidates working on dissertations directly associated with the project. In addition, three other Ph.D. candidates are working on dissertations involving other aspects of neutron physics in this laboratory

  12. Spectroscopic study of light scattering in linear alkylbenzene for liquid scintillator neutrino detectors

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiang; Zhang, Zhenyu [Wuhan University, Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan (China); Liu, Qian; Zheng, Yangheng [University of Chinese Academy of Sciences, School of Physics, Beijing (China); Han, Junbo [Huazhong University of Science and Technology, Wuhan National High Magnetic Field Center, Wuhan (China); Zhang, Xuan; Ding, Yayun; Zhou, Li; Cao, Jun; Wang, Yifang [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China)

    2015-11-15

    We have set up a light scattering spectrometer to study the depolarization of light scattering in linear alkylbenzene. The scattering spectra show that the depolarized part of light scattering is due to Rayleigh scattering. The additional depolarized Rayleigh scattering can make the effective transparency of linear alkylbenzene much better than expected. Therefore, sufficient scintillation photons can transmit through large liquid scintillator detector, such as that of the JUNO experiment. Our study is crucial to achieving an unprecedented energy resolution of 3 %/√(E(MeV)) required for the JUNO experiment to determine the neutrino mass hierarchy. The spectroscopic method can also be used to examine the depolarization of other organic solvents used in neutrino experiments. (orig.)

  13. Spectroscopic study of light scattering in linear alkylbenzene for liquid scintillator neutrino detectors

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xiang, E-mail: xiangzhou@whu.edu.cn [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, 430072, Wuhan (China); Liu, Qian, E-mail: liuqian@ucas.ac.cn [School of Physics, University of Chinese Academy of Sciences, 100049, Beijing (China); Han, Junbo [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, 430074, Wuhan (China); Zhang, Zhenyu [Hubei Nuclear Solid Physics Key Laboratory, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, 430072, Wuhan (China); Zhang, Xuan; Ding, Yayun [Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing (China); Zheng, Yangheng [School of Physics, University of Chinese Academy of Sciences, 100049, Beijing (China); Zhou, Li; Cao, Jun; Wang, Yifang [Institute of High Energy Physics, Chinese Academy of Sciences, 100049, Beijing (China)

    2015-11-21

    We have set up a light scattering spectrometer to study the depolarization of light scattering in linear alkylbenzene. The scattering spectra show that the depolarized part of light scattering is due to Rayleigh scattering. The additional depolarized Rayleigh scattering can make the effective transparency of linear alkylbenzene much better than expected. Therefore, sufficient scintillation photons can transmit through large liquid scintillator detector, such as that of the JUNO experiment. Our study is crucial to achieving an unprecedented energy resolution of 3 %/√(E(MeV)) required for the JUNO experiment to determine the neutrino mass hierarchy. The spectroscopic method can also be used to examine the depolarization of other organic solvents used in neutrino experiments.

  14. Studying time of flight imaging through scattering media across multiple size scales (Conference Presentation)

    Science.gov (United States)

    Velten, Andreas

    2017-05-01

    Light scattering is a primary obstacle to optical imaging in a variety of different environments and across many size and time scales. Scattering complicates imaging on large scales when imaging through the atmosphere when imaging from airborne or space borne platforms, through marine fog, or through fog and dust in vehicle navigation, for example in self driving cars. On smaller scales, scattering is the major obstacle when imaging through human tissue in biomedical applications. Despite the large variety of participating materials and size scales, light transport in all these environments is usually described with very similar scattering models that are defined by the same small set of parameters, including scattering and absorption length and phase function. We attempt a study of scattering and methods of imaging through scattering across different scales and media, particularly with respect to the use of time of flight information. We can show that using time of flight, in addition to spatial information, provides distinct advantages in scattering environments. By performing a comparative study of scattering across scales and media, we are able to suggest scale models for scattering environments to aid lab research. We also can transfer knowledge and methodology between different fields.

  15. Army Study Shows Decline In Behavioral Health Stigma

    Science.gov (United States)

    2012-01-01

    Army Study Shows Decline in Behavioral Health Stigma By Rob McIlvaine Army News Service WASHINGTON, Jan. 20, 2012 - A newly released Army study on...conference yesterday. The three-year study outlines the problem of suicide in the Army and related issues of substance abuse, spouse abuse and child abuse...REPORT TYPE 3. DATES COVERED 00-00-2012 to 00-00-2012 4. TITLE AND SUBTITLE Army Study Shows Decline In Behavioral Health Stigma 5a. CONTRACT

  16. Neutron scattering studies of the heavy Fermion superconductors

    International Nuclear Information System (INIS)

    Goldman, A.I.

    1985-01-01

    Recent neutron scattering measurements of the heavy Fermion superconductors are described. Those materials offer an exciting opportunity for neutron scattering since the f-electrons, which couple directly to magnetic scattering measurements, seem to be the same electrons which form the superconducting state below T/sub c/. In addition, studies of the magnetic fluctuations in these, and other heavy Fermion systems, by inelastic magnetic neutron scattering can provide information about the nature of the low temperature Fermi liquid character of these novel compounds

  17. Electron scattering studies by means of various nuclear models

    International Nuclear Information System (INIS)

    Essaniyazov, Sh.; Juraev, Sh.; Ismatov, E.I.

    2006-01-01

    Full text: Let us consider a general case of various interaction processes of electrons with nuclei. The study of the scattering o electrons of nuclei is the source of information on the structure of nuclei. At collision of fast electrons with nuclei, both elastic and inelastic scattering can be observed. Elastic scattering gives information on the sizes of nuclei, whereas the electrons inelastic scattering processes give important information on the dynamical properties of nuclei. In the first case, the characteristics of excited states, energy levels, their widths and others, and in the second case, momentum distribution of nucleons and other particles in nuclei are studied. Let us denote the momentum and the energy of the incident electron before and after the scattering as k and ε, and k' and ε', respectively. The angle between the vectors k and k' is denoted as θ. The scattering process is characterized by three parameters: k, k' and θ. However, it is convenient to introduce three other parameters instead of the indicated above. They are: energy ω ε - ε' and momentum q = k - k', transferred by electron at scattering, and the scattering angle θ. It is worth of mentioning the two reasons why the study of electron scattering is very effective tool to study the nuclear structure. First of all, the character of electron interaction with nucleus is a well-known electromagnetic interaction of electron with current and charge in nucleus. Secondly, this interaction is relatively weak (e 2 /ℎc) 2 = ω 2 is possible (since the photon mass is zero). In case of electrons, at fixed energy transfer ω various momentum transfer are possible. Therefore, at electron scattering study one can establish the dependence of the matrix elements of q, which are the Fourier-representations of the charge and current densities. Thus, it is possible to determine directly the spatial distribution of charge and current in nucleus. The inelastic scattering is accompanied by

  18. Surface magnetism studied by polarized light emission after He+ scattering

    NARCIS (Netherlands)

    Manske, J; Dirska, M; Lubinski, G; Schleberger, M; Narmann, A; Hoekstra, R

    Surface magnetism is studied by means of an ion beam of low energy (2-15 keV) scattered off the surface under grazing incidence conditions. During the scattering, a small fraction of the ions is neutralized into excited states which decay subsequently by light emission. The circular polarization of

  19. Scatter correction method with primary modulator for dual energy digital radiography: a preliminary study

    Science.gov (United States)

    Jo, Byung-Du; Lee, Young-Jin; Kim, Dae-Hong; Jeon, Pil-Hyun; Kim, Hee-Joung

    2014-03-01

    In conventional digital radiography (DR) using a dual energy subtraction technique, a significant fraction of the detected photons are scattered within the body, resulting in the scatter component. Scattered radiation can significantly deteriorate image quality in diagnostic X-ray imaging systems. Various methods of scatter correction, including both measurement and non-measurement-based methods have been proposed in the past. Both methods can reduce scatter artifacts in images. However, non-measurement-based methods require a homogeneous object and have insufficient scatter component correction. Therefore, we employed a measurement-based method to correct for the scatter component of inhomogeneous objects from dual energy DR (DEDR) images. We performed a simulation study using a Monte Carlo simulation with a primary modulator, which is a measurement-based method for the DEDR system. The primary modulator, which has a checkerboard pattern, was used to modulate primary radiation. Cylindrical phantoms of variable size were used to quantify imaging performance. For scatter estimation, we used Discrete Fourier Transform filtering. The primary modulation method was evaluated using a cylindrical phantom in the DEDR system. The scatter components were accurately removed using a primary modulator. When the results acquired with scatter correction and without correction were compared, the average contrast-to-noise ratio (CNR) with the correction was 1.35 times higher than that obtained without correction, and the average root mean square error (RMSE) with the correction was 38.00% better than that without correction. In the subtraction study, the average CNR with correction was 2.04 (aluminum subtraction) and 1.38 (polymethyl methacrylate (PMMA) subtraction) times higher than that obtained without the correction. The analysis demonstrated the accuracy of scatter correction and the improvement of image quality using a primary modulator and showed the feasibility of

  20. A Neutron Scattering Study of Collective Excitations in Superfluid Helium

    DEFF Research Database (Denmark)

    Graf, E. H.; Minkiewicz, V. J.; Bjerrum Møller, Hans

    1974-01-01

    Extensive inelastic-neutron-scattering experiments have been performed on superfluid helium over a wide range of energy and momentum transfers. A high-resolution study has been made of the pressure dependence of the single-excitation scattering at the first maximum of the dispersion curve over...... of the multiexcitation scattering was also studied. It is shown that the multiphonon spectrum of a simple Debye solid with the phonon dispersion and single-excitation cross section of superfluid helium qualitatively reproduces these data....

  1. Study of elastic scattering between heavy ions. Reaction channel influence

    International Nuclear Information System (INIS)

    Doubre, Hubert.

    1978-01-01

    The role of absorption on the behavior of heavy ion angular distributions and excitaton functions has been investigated on light and medium mass systems. Comparison between 20 Ne+ 12 C and 16 O+ 16 O systems which lead to the same compound nucleus, shows that it originates from the direct channels strongly coupled to the entrance channel. Structures in the excitation functions occur for almost all the light systems and it is shown that the damping observed for heavier systems such as 40 Ca+ 40 Ca, essentially results on the predominance of Coulomb effects which hide the nuclear structure effects. Thus no valuable information on the details of S-matrix can be extracted for such an heavy system. A coherent description of the elastic scattering, based on a splitting of the scattering amplitude into two components, the modulus of each component varying smoothly as a function of energy and angle. The interference between these sub-amplitudes give rise to interference effects in angular distributions and excitation functions. The study of the main reaction channels of the 40 Ca+ 40 Ca system - i.e. deep inelastic reactions and fusion - also shows that the closed-shell nature of the interacting nuclei does not play any role in these processes due to the excitation processes in the first stage of the reactions which destroy the specific structure of the nuclei [fr

  2. Annual report on neutron scattering studies in JAERI

    International Nuclear Information System (INIS)

    Sato, Masatoshi; Nishi, Masakazu; Fujishita, Hideshi; Iizumi, Masashi

    1982-07-01

    Neutron scattering studies carried out from September 1979 to August 1981 by Division of Physics, JAERI, and universities with JRR-2 and -3 neutron beam facilities are described: 61 summary reports, and a list of publications. (author)

  3. The dynamics of physisorbed layers studied by neutron scattering

    International Nuclear Information System (INIS)

    Nielsen, M.; McTague, J.P.

    1978-01-01

    We discuss the neutron scattering technique applied to the study of adsorbed thin films. Despite the fact that neutrons are scattered very weakly by surfaces, recent studies have shown that both structural and dynamical information can be obtained even for submonolayer coverages. Results will be shown for films of Ar, D 2 , H 2 , and O 2 adsorbed on (001) surfaces of graphite and for H 2 molecules adsorbed on activated alumina. (orig.) [de

  4. X-ray scattering studies of surfaces and interfaces

    International Nuclear Information System (INIS)

    Sanyal, M.K.

    1998-01-01

    Here we shall briefly review the basics and some applications of x-ray specular reflectivity and diffuse scattering techniques. These x-ray scattering techniques are uniquely suited to study of the structure of surfaces and interfaces at atomic resolutions as they are nondestructive and can probe even interfaces which are buried. The study of structure of surfaces and interfaces is not only required in understanding physics in reduced dimensions but is also essential in developing technologically important materials

  5. Resonance magnetic x-ray scattering study of erbium

    DEFF Research Database (Denmark)

    Sanyal, M.K.; Gibbs, D.; Bohr, J.

    1994-01-01

    The magnetic phases of erbium have been studied by resonance x-ray-scattering techniques. When the incident x-ray energy is tuned near the L(III) absorption edge, large resonant enhancements of the magnetic scattering are observed above 18 K. We have measured the energy and polarization dependence...... of this magnetic scattering and analyzed it using a simple model based on electric dipole and quadrupole transitions among atomic orbitals. The line shapes can be fitted to a magnetic structure combining both c-axis-modulated and basal-plane components. Below 18 K, we have observed unusual behavior of the magnetic...

  6. Inelastic Neutron Scattering Study of Mn

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Y.; Sarachik, M.P.; Friedman, J.R.; Robinson, R.A.; Kelley, T.M.; Nakotte, H.; Christianson, A.C.; Trouw, F.; Aubin, S.M.J.; Hendrickson, D.N.

    1998-11-09

    The authors report zero-field inelastic neutron scattering experiments on a 14-gram deuterated sample of Mn{sub 12}-Acetate consisting of a large number of identical spin-10 magnetic clusters. Their resolution enables them to see a series of peaks corresponding to transitions between the anisotropy levels within the spin-10 manifold. A fit to the spin Hamiltonian H = {minus}DS{sub z}{sup 2} + {mu}{sub B}B{center_dot}g{center_dot}S-BS{sub z}{sup 4} + C(S{sub +}{sup 4} + S{sub {minus}}{sup 4}) yields an anisotropy constant D = (0.54 {+-} 0.02) K and a fourth-order diagonal anisotropy coefficient B = (1.2 {+-} 0.1) x 10{sup {minus}3}K. Unlike EPR measurements, their experiments do not require a magnetic field and yield parameters that do not require knowledge of the g-value.

  7. Neutron scattering studies on chromatin higher-order structure

    Energy Technology Data Exchange (ETDEWEB)

    Graziano, V.; Gerchman, S.E.; Schneider, D.K.; Ramakrishnan, V. [Brookhaven National Laboratory, Upton, NY (United States)

    1994-12-31

    We have been engaged in studies of the structure and condensation of chromatin into the 30nm filament using small-angle neutron scattering. We have also used deuterated histone H1 to determine its location in the chromatin 30nm filament. Our studies indicate that chromatin condenses with increasing ionic strength to a limiting structure that has a mass per unit length of 6-7 nucleosomes/11 nm. They also show that the linker histone H1/H5 is located in the interior of the chromatin filament, in a position compatible with its binding to the inner face of the nucleosome. Analysis of the mass per unit length as a function of H5 stoichiometry suggests that 5-7 contiguous nucleosomes need to have H5 bound before a stable higher order structure can exist.

  8. Neutron scattering studies on chromatin higher-order structure

    International Nuclear Information System (INIS)

    Graziano, V.; Gerchman, S.E.; Schneider, D.K.; Ramakrishnan, V.

    1994-01-01

    We have been engaged in studies of the structure and condensation of chromatin into the 30nm filament using small-angle neutron scattering. We have also used deuterated histone H1 to determine its location in the chromatin 30nm filament. Our studies indicate that chromatin condenses with increasing ionic strength to a limiting structure that has a mass per unit length of 6-7 nucleosomes/11 nm. They also show that the linker histone H1/H5 is located in the interior of the chromatin filament, in a position compatible with its binding to the inner face of the nucleosome. Analysis of the mass per unit length as a function of H5 stoichiometry suggests that 5-7 contiguous nucleosomes need to have H5 bound before a stable higher order structure can exist

  9. The use of Raman scattering for studying the defects created by implantation in semiconductors

    International Nuclear Information System (INIS)

    Morhange, J.F.; Beserman, R.; Bourgoin, J.

    1974-01-01

    The evolution of Raman scattering with the dose of implanted ions and annealing temperature in silicon and diamond was studied. The variation in the concentration of the defects introduced by implantation, with the dose and annealing temperature were deduced. These results were compared with results obtained using electron paramagnetic resonance. The comparison shows that Raman scattering is a good technique to study the behavior of the defects in ion implanted semiconductors [fr

  10. Studies of Water by Scattering of Slow Neutrons

    International Nuclear Information System (INIS)

    Skoeld, K.; Pilcher, E.; Larsson, K.E.

    1964-01-01

    The quasielastic scattering peak in light water at room temperature has been studied with neutrons of energy ∼ 5x10 -3 eV. The width and shape of the peak has been determined by the time-of-flight technique at two scattering angles. If it is assumed that the broad inelastic spectrum is due to scattering by a monoatomic gas of mass 18, it is found that the quasielastic scattering is in good agreement with the predictions by the continuous diffusion model. Inelastic spectra were recorded up to 13x10 -3 eV. Indications of two discrete energy transfers (8 and 14x10 -4 eV) are observed in the 90 deg run. The results are discussed and compared with earlier observations

  11. ANGULAR LIGHT-SCATTERING STUDIES ON ISOLATED MITOCHONDRIA

    Science.gov (United States)

    Gotterer, Gerald S.; Thompson, Thomas E.; Lehninger, Albert L.

    1961-01-01

    Angular light-scattering studies have been carried out on suspensions of isolated rat liver mitochondria. The angular scatter pattern has a large forward component, typical of large particles. Changes in dissymmetry and in the intensity of light scattered at 90° have been correlated with changes in optical density during the course of mitochondrial swelling and contraction. Such changes can be measured at mitochondrial concentrations much below those required for optical density measurements. Changes in mitochondrial geometry caused by factors "leaking" from mitochondria, not detectable by optical density measurements, have been demonstrated by measuring changes in dissymmetry. Angular light-scattering measurements therefore offer the advantages of increased sensitivity and of added indices of changes in mitochondrial conformation. PMID:19866589

  12. Studies of Water by Scattering of Slow Neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Skoeld, K; Pilcher, E; Larsson, K E

    1964-01-15

    The quasielastic scattering peak in light water at room temperature has been studied with neutrons of energy {approx} 5x10{sup -3} eV. The width and shape of the peak has been determined by the time-of-flight technique at two scattering angles. If it is assumed that the broad inelastic spectrum is due to scattering by a monoatomic gas of mass 18, it is found that the quasielastic scattering is in good agreement with the predictions by the continuous diffusion model. Inelastic spectra were recorded up to 13x10{sup -3} eV. Indications of two discrete energy transfers (8 and 14x10{sup -4} eV) are observed in the 90 deg run. The results are discussed and compared with earlier observations.

  13. Study of scattering in bi-dimensional neutron radiographic images

    International Nuclear Information System (INIS)

    Oliveira, K.A.M. de; Crispim, V.R.; Silva, F.C.

    2009-01-01

    The effect of neutron scattering frequently causes distortions in neutron radiographic images and, thus, reduces the quality. In this project, a type of filter, comprised of cadmium (a neutron absorber), was used in the form of a grid to correct this effect. This device generated image data in the discrete shadow bands of the absorber, components relative to neutron scattering on the test object and surroundings. Scattering image data processing, together with the original neutron radiographic image, resulted in a corrected image with improved edge delineation and, thus, greater definition in the neutron radiographic image of the test object. The objective of this study is to propose a theoretical/experimental methodology that is capable of eliminating the components relative to neutron scattering in neutron radiographic images, coming from the material that composes the test object and the materials that compose the surrounding area. (author)

  14. Static and dynamic light scattering by red blood cells: A numerical study.

    Science.gov (United States)

    Mauer, Johannes; Peltomäki, Matti; Poblete, Simón; Gompper, Gerhard; Fedosov, Dmitry A

    2017-01-01

    Light scattering is a well-established experimental technique, which gains more and more popularity in the biological field because it offers the means for non-invasive imaging and detection. However, the interpretation of light-scattering signals remains challenging due to the complexity of most biological systems. Here, we investigate static and dynamic scattering properties of red blood cells (RBCs) using two mesoscopic hydrodynamics simulation methods-multi-particle collision dynamics and dissipative particle dynamics. Light scattering is studied for various membrane shear elasticities, bending rigidities, and RBC shapes (e.g., biconcave and stomatocyte). Simulation results from the two simulation methods show good agreement, and demonstrate that the static light scattering of a diffusing RBC is not very sensitive to the changes in membrane properties and moderate alterations in cell shapes. We also compute dynamic light scattering of a diffusing RBC, from which dynamic properties of RBCs such as diffusion coefficients can be accessed. In contrast to static light scattering, the dynamic measurements can be employed to differentiate between the biconcave and stomatocytic RBC shapes and generally allow the differentiation based on the membrane properties. Our simulation results can be used for better understanding of light scattering by RBCs and the development of new non-invasive methods for blood-flow monitoring.

  15. Electron scattering studies of nitrogen dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Dhanoj; Naghma, Rahla [Department of Applied Physics, Indian School of Mines, Dhanbad 826004, Jharkhand (India); Vinodkumar, Minaxi [V. P. and R. P. T. P. Science College, Vallabh Vidyanagar 388120, Gujarat (India); Antony, Bobby, E-mail: bka.ism@gmail.com [Department of Applied Physics, Indian School of Mines, Dhanbad 826004, Jharkhand (India)

    2013-12-15

    Highlights: •Two quantum mechanical models used to find TCS for e-NO{sub 2} from 0.5 to 2000 eV. •R-matrix method at low energies (<15 eV) and SCOP at high energies (16 to 2000 eV). •Besides CS, R-matrix method predicts resonances and possibility of DEA formation. •SCOP formalism is used to find total inelastic and elastic CS at high energies. •Resonances detected at 1.33, 3 and 8.41 eV is associated with O{sup −} anion formation by DEA. -- Abstract: Present work reports total cross sections for e-NO{sub 2} scattering over an extensive range of impact energy from 0.5 eV to 2000 eV, through a composite formalism. The ab initio R-matrix method is employed for calculations up to 15 eV while the spherical complex optical potential formalism is used beyond that energy. The electronic excitation cross sections are computed from ground state X{sup 2}A{sub 1} to seven electronically allowed excited states {sup 2}B{sub 1}, {sup 2}B{sub 2}, {sup 2}A{sub 2}, {sup 4}A{sub 2}, {sup 4}B{sub 2}, {sup 4}A{sub 1}, {sup 4}A{sub 1} and {sup 4}B{sub 1}. The eigenphase diagrams presented here reproduces the resonances identified earlier. The structures detected at 1.33, 3 and 8.41 eV can be associated with the observed O{sup −} anion formation through dissociative electron attachment process.

  16. Studies on biological macromolecules by neutron inelastic scattering

    International Nuclear Information System (INIS)

    Fujiwara, Satoru; Nakagawa, Hiroshi

    2013-01-01

    Neutron inelastic scattering techniques, including quasielastic and elastic incoherent neutron scattering, provide unique tools to directly measure the protein dynamics at a picosecond time scale. Since the protein dynamics at this time scale is indispensable to the protein functions, elucidation of the protein dynamics is indispensable for ultimate understanding of the protein functions. There are two complementary directions of the protein dynamics studies: one is to explore the physical basis of the protein dynamics using 'model' proteins, and the other is more biology-oriented. Examples of the studies on the protein dynamics with neutron inelastic scattering are described. The examples of the studies in the former direction include the studies on the dynamical transitions of the proteins, the relationship between the protein dynamics and the hydration water dynamics, and combined analysis of the protein dynamics with molecular dynamics simulation. The examples of the studies in the latter direction include the elastic incoherent and quasielastic neutrons scattering studies of actin. Future prospects of the studies on the protein dynamics with neutron scattering are briefly described. (author)

  17. Small-angle neutron scattering studies on water soluble complexes ...

    Indian Academy of Sciences (India)

    ... by small-angle neutron scattering. SANS data showed a positive indication of the formation of RCP-SDS complexes. Even though the complete structure of the polyion complexes could not be ascertained, the results obtained give us the information on the local structure in these polymer-surfactant systems. The data were ...

  18. Insulin association in neutral solutions studied by light scattering

    DEFF Research Database (Denmark)

    Hvidt, S.

    1991-01-01

    Molecular weights and weight distributions of sulfated, Zn-free, and 2Zn insulins have been measured at pH 7.3 as a function of concentration from 0.1 to 2 mg/ml by use of a combination of light scattering, refractometry, and size-exclusion chromatography. Results show that sulfated insulin...

  19. A combined neutron scattering and simulation study on bioprotectant systems

    Energy Technology Data Exchange (ETDEWEB)

    Affouard, F. [Laboratoire de Dynamique et Structure des Materiaux Moleculaires UMR 8024, Universite Lille I - 59655 Villeneuve d' Ascq cedex (France); Bordat, P. [Laboratoire de Dynamique et Structure des Materiaux Moleculaires UMR 8024, Universite Lille I - 59655 Villeneuve d' Ascq cedex (France); Descamps, M. [Laboratoire de Dynamique et Structure des Materiaux Moleculaires UMR 8024, Universite Lille I - 59655 Villeneuve d' Ascq cedex (France); Lerbret, A. [Laboratoire de Dynamique et Structure des Materiaux Moleculaires UMR 8024, Universite Lille I - 59655 Villeneuve d' Ascq cedex (France); Magazu, S. [Dipartimento di Fisica and INFM, Universita di Messina, P.O. Box 55, I-98166 Messina (Italy); Migliardo, F. [Laboratoire de Dynamique et Structure des Materiaux Moleculaires UMR 8024, Universite Lille I - 59655 Villeneuve d' Ascq cedex (France); Dipartimento di Fisica and INFM, Universita di Messina, P.O. Box 55, I-98166 Messina (Italy)], E-mail: fmigliardo@unime.it; Ramirez-Cuesta, A.J. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot (United Kingdom); Telling, M.F.T. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot (United Kingdom)

    2005-10-31

    The present work shows quasi elastic neutron scattering, neutron spin echo and inelastic neutron scattering results on a class of bioprotectant systems, such as homologous disaccharides (i.e., trehalose and sucrose)/water solutions, as a function of temperature. The whole set of findings indicates a noticeable 'kosmotrope' character of the disaccharides, and in particular of trehalose, which is able to strongly modify both the structural and dynamical properties of water. This superior capability of trehalose can be linked to its higher bioprotective effectiveness in respect with the other disaccharides.

  20. Contribution of ultrasound forward scattering to tissue structure study

    International Nuclear Information System (INIS)

    Edee, M.K.

    1987-12-01

    In this paper, we show how to get useful information of tissue structure by merely interpreting some experimental graphs such as energy spectral density and autocorrelation function of an ultrasonic beam travelling through tissues. To support these interpretations, we needed just some well-known theorems rather than heavy and complicated mathematical equations, so we measured the dimensions of scatterers within specimens by using the graphical representation of autocorrelation function. We related these measurements to the scattered peaks which appear in energy density spectrum. The values we found were equal to those obtained from biologists within ∼ 15%. (author) 26 refs, 6 figs, tabs

  1. Experimental study of inclusive deep inelastic neutrino--proton scattering

    International Nuclear Information System (INIS)

    Berge, J.P.; Bogert, D.; DiBianca, F.A.; Cundy, D.C.; Dunaitsev, A.; Efremenko, V.; Ermolov, P.; Fowler, W.; Hanft, R.; Harigel, G.; Huson, F.R.; Kolganov, V.; Mukhin, A.; Nezrick, F.A.; Rjabov, Y.; Scott, W.G.; Smart, W.; Coffin, C.T.; Diamond, R.N.; French, H.; Louis, W.; Roe, B.P.; Seidl, A.A.; Velde, J.C.V.

    1976-01-01

    A neutrino--proton scattering experiment has been performed at Fermilab by using a wide-band horn-focused neutrino beam and the 15-ft bubble chamber filled with hydrogen. For the inclusive reaction ν/sub μ/ + p → μ - + hadrons, the mean value of Q 2 is found to increase linearly with energy, as is expected from Bjorken scaling, and a fit to the data gives 2 > = (0.18 +- 0.01) E. The distribution in the Bjorken scaling variable x shows evidence for deviations from predictions based on electron-scattering data and the quark-parton model

  2. Light and neutron scattering study of strongly interacting ionic micelles

    International Nuclear Information System (INIS)

    Degiorgio, V.; Corti, M.; Piazza, R.

    1989-01-01

    Dilute solutions of ionic micelles formed by biological glycolipids (gangliosides) have been investigated at various ionic strengths by static and dynamic light scaterring and by small-angle neutron scattering. The size and shape of the micelle is not appreciably affected by the added salt concentration in the range 0-100 mM NaCL. From the measured intensity of scattered light we derive the electric charge Z of the micelle by fitting the data to a theoretical calculation which uses a screened Coulomb potential for the intermicellar interaction, and the hypernetted chain approximation for the calculation of the radial distribution function. The correlation function derived from dynamic light scattering shows the long time contribution typical of concentrated polydisperse systems (author). 15 refs.; 6 figs

  3. An inelastic neutron scattering study of hematite nanoparticles

    DEFF Research Database (Denmark)

    Hansen, Mikkel Fougt; Klausen, Stine Nyborg; Lefmann, K

    2003-01-01

    We have studied the magnetic dynamics in nanocrystalline hematite by inelastic neutron scattering at the high-resolution time-of-flight spectrometer IRIS at ISIS. Compared to previous inelastic neutron scattering experiments an improvement of the resolution function is achieved and more detailed...... moment at the antiferromagnetic Bragg reflection. We have studied different weightings of the particle size distribution. The data and their temperature dependence can with good agreement be interpreted on the basis of the Neel-Brown theory for superparamagnetic relaxation and a model for the collective...

  4. Scatter correction using a primary modulator for dual energy digital radiography: A Monte Carlo simulation study

    Science.gov (United States)

    Jo, Byung-Du; Lee, Young-Jin; Kim, Dae-Hong; Kim, Hee-Joung

    2014-08-01

    In conventional digital radiography (DR) using a dual energy subtraction technique, a significant fraction of the detected photons are scattered within the body, making up the scatter component. Scattered radiation can significantly deteriorate image quality in diagnostic X-ray imaging systems. Various methods of scatter correction, including both measurement- and non-measurement-based methods, have been proposed in the past. Both methods can reduce scatter artifacts in images. However, non-measurement-based methods require a homogeneous object and have insufficient scatter component correction. Therefore, we employed a measurement-based method to correct for the scatter component of inhomogeneous objects from dual energy DR (DEDR) images. We performed a simulation study using a Monte Carlo simulation with a primary modulator, which is a measurement-based method for the DEDR system. The primary modulator, which has a checkerboard pattern, was used to modulate the primary radiation. Cylindrical phantoms of variable size were used to quantify the imaging performance. For scatter estimates, we used discrete Fourier transform filtering, e.g., a Gaussian low-high pass filter with a cut-off frequency. The primary modulation method was evaluated using a cylindrical phantom in the DEDR system. The scatter components were accurately removed using a primary modulator. When the results acquired with scatter correction and without scatter correction were compared, the average contrast-to-noise ratio (CNR) with the correction was 1.35 times higher than that obtained without the correction, and the average root mean square error (RMSE) with the correction was 38.00% better than that without the correction. In the subtraction study, the average CNR with the correction was 2.04 (aluminum subtraction) and 1.38 (polymethyl methacrylate (PMMA) subtraction) times higher than that obtained without the correction. The analysis demonstrated the accuracy of the scatter correction and the

  5. High vacuum general purpose scattering chamber for nuclear reaction study

    International Nuclear Information System (INIS)

    Suresh Kumar; Ojha, S.C.

    2003-01-01

    To study the nuclear reactions induced by beam from medium energy accelerators, one of the most common facility required is a scattering chamber. In the scattering chamber, projectile collides with the target nucleus and the scattered reaction products are detected with various type of nuclear detector at different angles with respect to the beam. The experiments are performed under high vacuum to minimize the background reaction and the energy losses of the charged particles. To make the chamber general purpose various requirement of the experiments are incorporated into it. Changing of targets, changing angle of various detectors while in vacuum are the most desired features. The other features like ascertaining the beam spot size and position on the target, minimizing the background counts by proper beam dump, accurate positioning of the detector as per plan etc. are some of the important requirements

  6. Study of the electrons elastic scattering by atoms through pseudopotentials

    International Nuclear Information System (INIS)

    Bettega, M.H.F.

    1990-01-01

    Pseudopotentials allow an extraordinary simplification in the calculation of the electronic structure of atoms, molecules and crystals. Though they have been used extensively for electronic structure calculations, little is known of their applicability to scattering. A study of the pseudopotentials of Bachelet, Hamann and Schuter in the electron scattering by atoms was made, calculating phase-shifts and cross sections for angular momenta 1=0,1 and 2 and energy up to 5 R y. The results for the pseudopotential were compared all-electron calculations. The agreement is very good in a broad energy band. A simplification of the calculation of scattering by complex molecules where an all-electron calculation is impossible is aimed. (author)

  7. Experimental study of intensive electron beam scattering in melting channel

    International Nuclear Information System (INIS)

    Balagura, V.S.; Kurilko, V.I.; Safronov, B.G.

    1988-01-01

    Multiple scattering of an intensive electron beam at 28 keV energy passing through a melting channel in iron targets is experimentally studied. The dependence of scattering on the melting current value is established. The material density in the channel on the basis of the binary collision method is evaluated. It is shown that these density values are of three orders less than the estimations made on the basis of the data on energy losses of electrons in the channel. 6 refs.; 4 figs

  8. Neutron-scattering studies of magnetic superconductors

    International Nuclear Information System (INIS)

    Sinha, S.K.; Crabtree, G.W.; Hinks, D.G.; Mook, H.A.; Pringle, O.A.

    1982-01-01

    Results obtained in the last few years obtained by neutron diffraction on the nature of the magnetic ordering in magnetic superconductors are reviewed. Emphasis is given to studies of the complex intermediate phase in ferromagnetic superconductors where both superconductivity and ferromagnetism appear to coexist

  9. Phase separation process in FeCr alloys studied by neutron small angle scattering

    International Nuclear Information System (INIS)

    Furusaka, Michihiro; Ishikawa, Yoshikazu; Yamaguchi, Sadae; Fujino, Yutaka.

    1986-01-01

    The very early stage as well as late stage of phase separation process in FeCr alloys (Fe-20, 30, 40, 60 at%Cr) have been studied by pulsed cold neutron small angle scattering instrument (SAN). At the early stage, scattering intensity I(q) obeys q -2 dependence at the high q side of the scattering function. The results are in accord with the theory of Langer et al. which takes into account nonlinear and thermal fluctuations effects. At the late stage where I(q) shows q -4 dependence, a dynamical scaling law holds, while it is not the case for the earlier stage. Phase diagram of FeCr system is also determined by critical scattering measurements. (author)

  10. Case Study Shows Disconnect on Civic Journalism's Role

    OpenAIRE

    Tully, M.; Harmsen, S.; Singer, J.; Ekdale, B.

    2017-01-01

    This in-depth case study examines attempts to transform a traditional newsroom to one oriented around civic journalism principles, offering a unique look at the resistance toward those principles even in a digital environment that facilitates new audience relationships. Civic journalism emphasizes understanding and addressing community concerns from a citizen perspective. This study finds that journalists still struggle to integrate citizens’ contributions into newsroom practice in meaningful...

  11. Studies of magnetism with inelastic scattering of cold neutrons

    International Nuclear Information System (INIS)

    Jacrot, B.

    1964-01-01

    Inelastic scattering of cold neutrons can be used to study some aspects of magnetism: spins waves, exchange integrals, vicinity of Curie point. After description of the experimental set-up, several experiments, in the fields mentioned above, are analysed. (author) [fr

  12. Multiple scattering in synchrotron studies of disordered materials

    International Nuclear Information System (INIS)

    Poulsen, H.F.; Neuefeind, J.

    1995-01-01

    A formalism for the multiple scattering and self-absorption in synchrotron studies of disordered materials is presented. The formalism goes beyond conventionally used approximations and treat the cross sections, the beam characteristics, the state of polarization, and the electronic correction terms in full. Using hard X-rays it is shown how the simulated distributions can be directly compared to experimental data. ((orig.))

  13. Small angle neutron scattering studies on the interaction of cationic

    Indian Academy of Sciences (India)

    The structure of the protein–surfactant complex of bovine serum albumin (BSA) and cationic surfactants has been studied by small angle neutron scattering. At low concentrations, the CTAB monomers are observed to bind to the protein leading to an increase in its size. On the other hand at high concentrations, surfactant ...

  14. Oklahoma Cherokee formation study shows benefits of gas tax credits

    International Nuclear Information System (INIS)

    Stanley, B.J.; Cline, S.B.

    1994-01-01

    To no one's surprise, the administration's recently released energy initiative package does not advocate the use of tax incentives such as the Internal Revenue Code Sec. 29 (tight sand gas) credit that expired Dec. 31, 1992. This is unfortunate since tax credits do stimulate drilling, as the authors' recent study of Oklahoma's Pennsylvanian age Cherokee formation demonstrates. Within this 783,000 acre study area, more than 130 additional wells were drilled between 1991--92 because of tax credit incentives. And such tax credits also increase total federal tax revenues by causing wells to be drilled that would not have been drilled or accelerating the drilling of wells, thereby increasing taxable revenue. In short, tax credits create a win-win situation: they stimulate commerce, increase tax revenues, reduce the outflow of capital to foreign petroleum projects, and add to the nation's natural gas reserve, which is beneficial for national security, balance of payments, the environment, and gas market development. The paper discusses the study assumptions, study results, and the tax credit policy

  15. Study of Coulomb effects using the comparison of positrons and electrons elastic scattering on nuclei

    International Nuclear Information System (INIS)

    Breton, Vincent

    1990-01-01

    We have studied Coulomb effects in the electron-nucleus interaction by measuring electron and positron elastic scattering. The Coulomb field of the nucleus acts differently on theses particles because of their opposite charges. The experiment took place at the Accelerateur Lineaire de Saclay, with 450 MeV electrons and positrons. We measured the emittance of the positron and electron beams. We compared electron and positron beams having the same energy, the same emittance and the same intensity. This way, we measured positron scattering cross sections with 2 % systematic error. By comparing positron and electron elastic scattering cross sections for momentum transfers between 1 and 2 fm -1 , on a Lead 208 target, we showed that the calculations of Coulomb effects in elastic scattering are in perfect agreement with experimental results. The comparison of positron and electron elastic scattering cross sections on Carbon showed that dispersive effects are smaller than 2 % outside the diffraction minima. These two results demonstrate in a definitive way that electron scattering allows to measure charge densities in the center of nuclei with an accuracy of the order of 1 %. (author) [fr

  16. A study on the distribution of scatter ray in chest radiography of a health examination bus

    International Nuclear Information System (INIS)

    Cho, Ji Hwan; Jin, Seong Jin; Min, Byeong In

    2017-01-01

    The purpose of this study was to evaluate the distribution of spatial scatter ray on the chest radiographs of patients on health examination bus. In this paper, we propose a method for minimize unnecessary exposure by measuring the scattered dose after exposure the actual subject and comparing the body mass index (BMI) with the tube current amount mAs. The results of this study showed that the mean BMI of the subjects was 23.31±3.12. The mean mAs value was 2.92±1.19, which males was higher than females. The mean value of the scatter ray at position 1 in the radiography room was 771.81±151.15 μ/hr. The mean value of the scatter rays at the position 2 outside the entrance of the radiography room was measured as 53.86±25.66 μ/hr. As the BMI and mAs was increase the spatial scatter dose was increased at position 1 and position 2 in the photographing room. In order to minimize the exposure dose of scatter ray, radiation workers should shoot the radiation as low as possible within the range that does not impair the quality of the image. It will be necessary to make efforts to not wait for a waiting person near the entrance door of the photographing room

  17. A study on the distribution of scatter ray in chest radiography of a health examination bus

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Ji Hwan [Dept. of Health Care Clinic, Inje University Busan Paik Hospital, Busan (Korea, Republic of); Jin, Seong Jin [Gammaknife center, Inje University Haeundae Paik Hospital, Busan (Korea, Republic of); Min, Byeong In [Dept. of of Nuclear Applied Engineering, Inje University, Incheon (Korea, Republic of)

    2017-09-15

    The purpose of this study was to evaluate the distribution of spatial scatter ray on the chest radiographs of patients on health examination bus. In this paper, we propose a method for minimize unnecessary exposure by measuring the scattered dose after exposure the actual subject and comparing the body mass index (BMI) with the tube current amount mAs. The results of this study showed that the mean BMI of the subjects was 23.31±3.12. The mean mAs value was 2.92±1.19, which males was higher than females. The mean value of the scatter ray at position 1 in the radiography room was 771.81±151.15 μ/hr. The mean value of the scatter rays at the position 2 outside the entrance of the radiography room was measured as 53.86±25.66 μ/hr. As the BMI and mAs was increase the spatial scatter dose was increased at position 1 and position 2 in the photographing room. In order to minimize the exposure dose of scatter ray, radiation workers should shoot the radiation as low as possible within the range that does not impair the quality of the image. It will be necessary to make efforts to not wait for a waiting person near the entrance door of the photographing room.

  18. Studies of the dynamic properties of materials using neutron scattering

    International Nuclear Information System (INIS)

    Lovesey, S.W.; Windsor, C.G.

    1985-09-01

    The dynamic properties of materials using the neutron scattering technique is reviewed. The basic properties of both nuclear scattering and magnetic scattering are summarized. The experimental methods used in neutron scattering are described, along with access to neutron sources, and neutron inelastic instruments. Applied materials science using inelastic neutron scattering; rotational tunnelling of a methyl group; molecular diffusion from quasi-elastic scattering; and the diffusion of colloidal particles and poly-nuclear complexes; are also briefly discussed. (U.K.)

  19. Study on the scattering law and scattering kernel of hydrogen in zirconium hydride

    International Nuclear Information System (INIS)

    Jiang Xinbiao; Chen Wei; Chen Da; Yin Banghua; Xie Zhongsheng

    1999-01-01

    The nuclear analytical model of calculating scattering law and scattering kernel for the uranium zirconium hybrid reactor is described. In the light of the acoustic and optic model of zirconium hydride, its frequency distribution function f(ω) is given and the scattering law of hydrogen in zirconium hydride is obtained by GASKET. The scattering kernel σ l (E 0 →E) of hydrogen bound in zirconium hydride is provided by the SMP code in the standard WIMS cross section library. Along with this library, WIMS is used to calculate the thermal neutron energy spectrum of fuel cell. The results are satisfied

  20. Understanding the scatter radiation distribution during C-arm CT examination. A body phantom study

    International Nuclear Information System (INIS)

    Norimasa, Toshiyo; Kakimi, Akihiko; Takao, Yoshinori; Sasaki, Shohei; Katayama, Yutaka; Himoto, Daisuke; Izuta, Shinichiro; Ichida, Takao

    2016-01-01

    The purpose of this study was to understand the scatter radiation distribution during C-arm CT examination in the interventional radiography (IVR) room to show the escaped area and the radiation protective method. The C-arm rotates 200deg in 5 s. The tube voltage was 90 kV, and the entrance dose to the detector was 0.36 μGy/frame during C-arm CT examination. The scattered doses were measured each 50 cm from the isocenter like a grid pattern. The heights of the measurement were 50, 100, and 150 cm from the floor. The maximum scattered doses were 38.23 ± 0.60 μGy at 50 cm, 43.86 ± 20 μGy at 100 cm, and 25.78 ± 0.37 μGy at 150 cm. The scatter radiation distribution at 100 cm was the highest scattered dose. The operator should protect their reproductive gland, thyroid, and lens. The scattered dose was low behind the C-arm body and the bed, so they will be able to become the escaped area for staff. (author)

  1. Some neutron scattering studies on magnetic and molecular phase transitions

    International Nuclear Information System (INIS)

    Bevaart, L.

    1978-01-01

    In this thesis neutron-scattering investigations on two different systems are described. The first study is concerned with the magnetic ordering phenomena in pseudo two-dimensional (d = 2), two-component antiferromagnets K 2 Mnsub(1-x)Msub(x)F 4 (M = Fe, Co), as a function of the composition x and temperature T. For one of the samples in this series, K 2 Musub(0.978)Fesub(0.022)F 4 , the influence of an external magnetic field on the ordering characteristics was studied in addition. The second study deals with the rotational motions of the NH 4 + groups in NH 4 ZnF 3 in relation with the structural phase transition at Tsub(c) = 115.1 K. The experimental techniques were chosen according to the requirements of each of these two subjects. The former study was carried out by observing the elastic magnetic neutron scattering with a double-axis diffractometer, whereas for the latter study time-of-flight (TOF) techniques were applied to observe the inelastic and quasi-elastic incoherent neutron scattering by the protons of the rotating NH 4 + groups. (Auth.)

  2. Neutron scattering and HPLC study on L-ascorbic acid and its degradation

    Energy Technology Data Exchange (ETDEWEB)

    Bellocco, E. [Department of Organic and Biological Chemistry, University of Messina, Messina (Italy)], E-mail: bellocco@isengard.unime.it; Barreca, D.; Lagana, G.; Leuzzi, U. [Department of Organic and Biological Chemistry, University of Messina, Messina (Italy); Migliardo, F.; Torre, R. La; Galli, G. [Department of Physics, University of Messina, Messina (Italy); Galtieri, A. [Department of Organic and Biological Chemistry, University of Messina, Messina (Italy); Minutoli, L.; Squadrito, F. [Department of Clinical and Experimental Medicine and Pharmacology, University of Messina, Messina (Italy)

    2008-04-18

    The present paper shows a systematic dynamic and kinetic study on L-ascorbic acid and its degradation at high temperature. The neutron scattering study allows, through the behavior of quasi-elastic neutron scattering (QENS) spectra, to characterize the diffusive dynamics of L-ascorbic acid in water mixtures. Ascorbic acid undergoes degradation process at high temperature, but the presence of trehalose in solution markedly avoids ascorbic acid loss enhancing its t{sub 1/2} (half life time), as determined by high performance liquid chromatography (HPLC)

  3. Neutron scattering and HPLC study on L-ascorbic acid and its degradation

    International Nuclear Information System (INIS)

    Bellocco, E.; Barreca, D.; Lagana, G.; Leuzzi, U.; Migliardo, F.; Torre, R. La; Galli, G.; Galtieri, A.; Minutoli, L.; Squadrito, F.

    2008-01-01

    The present paper shows a systematic dynamic and kinetic study on L-ascorbic acid and its degradation at high temperature. The neutron scattering study allows, through the behavior of quasi-elastic neutron scattering (QENS) spectra, to characterize the diffusive dynamics of L-ascorbic acid in water mixtures. Ascorbic acid undergoes degradation process at high temperature, but the presence of trehalose in solution markedly avoids ascorbic acid loss enhancing its t 1/2 (half life time), as determined by high performance liquid chromatography (HPLC)

  4. Applications of neutron scattering to the study of magnetic materials

    International Nuclear Information System (INIS)

    Koehler, W.C.

    1976-01-01

    The types of interactions that neutrons undergo with condensed matter are reviewed and those properties of neutrons that make them an ideal probe for the study of magnetism on a microscopic scale are discussed. Following a very brief survey of experimental methods, a few illustrative examples of specific investigations are described in sufficient detail to illustrate the power of the techniques. Views as to the future directions that may be taken by neutron scattering are presented

  5. Theoretical study of near-threshold electron-molecule scattering

    International Nuclear Information System (INIS)

    Morrison, M.A.

    1989-01-01

    We have been engaged in carrying out a foundation study on problems pertaining to near-threshold nuclear excitations in e-H 2 scattering. The primary goals of this study are: to investigate the severity and nature of the anticipated breakdown of the adiabatic-nuclei (AN) approximation, first for rotation only (in the rigid-rotator approximation), and then for vibration; to determine a data base of accurate ab initio cross sections for this important system; to implement and test accurate, computationally-tractable model potentials for exchange and polarization effects; and to begin the exploration of alternative scattering theories for near-threshold collisions. This study has provided a well-defined theoretical context for our future investigations. Second, it has enabled us to identify and quantify several serious problems in the theory of near-threshold electron-molecule scattering that demand attention. And finally, it has led to the development of some of the theoretical and computational apparatus that will form the foundation of future work. In this report, we shall review our progress to date, emphasizing work completed during the current contract year. 17 refs., 5 figs., 1 tab

  6. Small-angle scattering study of Aspergillus awamori glycoprotein glucoamylase

    International Nuclear Information System (INIS)

    Schmidt, A. E.; Shvetsov, A. V.; Kuklin, A. I.; Lebedev, D. V.; Surzhik, M. A.; Sergeev, V. R.; Isaev-Ivanov, V. V.

    2016-01-01

    Glucoamylase from fungus Aspergillus awamori is glycoside hydrolase that catalyzes the hydrolysis of α-1,4- and α-1,6-glucosidic bonds in glucose polymers and oligomers. This glycoprotein consists of a catalytic domain and a starch-binding domain connected by an O-glycosylated polypeptide chain. The conformation of the linker, the relative arrangement of the domains, and the structure of the full-length enzyme are unknown. The structure of the recombinant glucoamylase GA1 was studied by molecular modelling and small-angle neutron scattering (SANS) methods. The experimental SANS data provide evidence that glucoamylase exists as a monomer in solution and contains a glycoside component, which makes a substantial contribution to the scattering. The model of full-length glucoamylase, which was calculated without taking into account the effect of glycosylation, is consistent with the experimental data and has a radius of gyration of 33.4 ± 0.6 Å

  7. Small-angle scattering study of Aspergillus awamori glycoprotein glucoamylase

    Science.gov (United States)

    Schmidt, A. E.; Shvetsov, A. V.; Kuklin, A. I.; Lebedev, D. V.; Surzhik, M. A.; Sergeev, V. R.; Isaev-Ivanov, V. V.

    2016-01-01

    Glucoamylase from fungus Aspergillus awamori is glycoside hydrolase that catalyzes the hydrolysis of α-1,4- and α-1,6-glucosidic bonds in glucose polymers and oligomers. This glycoprotein consists of a catalytic domain and a starch-binding domain connected by an O-glycosylated polypeptide chain. The conformation of the linker, the relative arrangement of the domains, and the structure of the full-length enzyme are unknown. The structure of the recombinant glucoamylase GA1 was studied by molecular modelling and small-angle neutron scattering (SANS) methods. The experimental SANS data provide evidence that glucoamylase exists as a monomer in solution and contains a glycoside component, which makes a substantial contribution to the scattering. The model of full-length glucoamylase, which was calculated without taking into account the effect of glycosylation, is consistent with the experimental data and has a radius of gyration of 33.4 ± 0.6 Å.

  8. Optical potential study of electron scattering by rubidium

    Energy Technology Data Exchange (ETDEWEB)

    Chin, J. H.; Ratnavelu, K. [University of Malaya, Kuala Lumpur (Malaysia); Zhou, Y. [Harbin Institute of Technology, Harbin (China)

    2011-10-15

    The coupled-channel optical method (CCOM) has been implemented in a study of electronrubidium scattering. This method includes the continuum effect in the calculation via an ab-initio optical potential. Eight atomic states (5s, 5p, 4d, 6s, 6p, 5d, 7s, 7p) were used together with the continuum optical potential in the 5s-5s, 5s-5p, and 5p-5p coupling. The elastic, inelastic and total cross sections for electron-rubidium scattering at low and intermediate energies, ranging from 10 eV to 100 eV, are reported. The results are compared with available experimental and theoretical data.

  9. Spin dynamics above the Curie temperature studied by neutron scattering

    International Nuclear Information System (INIS)

    Steinsvoll, O.; Riste, T.

    1986-01-01

    Neutron scattering can in principle give information about magnetic fluctuations over the entire atomic space and time domain. The weakness of the neutron-matter interaction renders this information undistorted by the neutron probe, but at the same time puts intensity limitations on the method. A considerable number of studies on the magnetism of 3d metals have been performed at some of the larger reactor laboratories. In the regions of overlap the experimental results from the different laboratories are consistent, but the interpretations are along different lines. Among the controversial issues are itinerancy versus localization, the degree of order above T C . In our talk we shall give an introduction to the neutron scattering method, including some of the sophisticated polarized beam methods. In the rest of the talk we shall review recent experimental results and some of the theoretical models used in their interpretation. (orig.)

  10. Study of a new scatter rejection technique in digital radiography

    International Nuclear Information System (INIS)

    Bottari, S.; Ciocci, M.A.; Fortunato, M.; Maestro, P.; Malakhov, N.; Marrocchesi, P.S.; Meucci, M.; Millucci, V.; Paoletti, R.; Scribano, A.; Turini, N.

    2001-01-01

    A new technique for digital mammography based on the use of a collimator and an anti-scatter grid coupled with a mosaic detector has been studied with a Monte Carlo program. The simulation, with a low-energy spectrum X-ray beam and a breast phantom, provides a quantitative assessment of the capability of the method to reduce the physical background of the image due to scattering in the body, without introducing image artifacts. With minor modifications to the existing X-ray facilities, the method could also be applied to area detectors. To verify the results of the simulation, an experimental setup based on a CCD camera coupled via a fiber optic plate to a CsI(Tl) scintillator is under test

  11. Study of a new scatter rejection technique in digital radiography

    Energy Technology Data Exchange (ETDEWEB)

    Bottari, S.; Ciocci, M.A. E-mail: ciocci@pi.infn.it; Fortunato, M.; Maestro, P.; Malakhov, N.; Marrocchesi, P.S.; Meucci, M.; Millucci, V.; Paoletti, R.; Scribano, A.; Turini, N

    2001-04-01

    A new technique for digital mammography based on the use of a collimator and an anti-scatter grid coupled with a mosaic detector has been studied with a Monte Carlo program. The simulation, with a low-energy spectrum X-ray beam and a breast phantom, provides a quantitative assessment of the capability of the method to reduce the physical background of the image due to scattering in the body, without introducing image artifacts. With minor modifications to the existing X-ray facilities, the method could also be applied to area detectors. To verify the results of the simulation, an experimental setup based on a CCD camera coupled via a fiber optic plate to a CsI(Tl) scintillator is under test.

  12. Small-angle scattering study of Aspergillus awamori glycoprotein glucoamylase

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, A. E., E-mail: schmidt@omrb.pnpi.spb.ru; Shvetsov, A. V. [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute (Russian Federation); Kuklin, A. I. [Joint Institute for Nuclear Research (Russian Federation); Lebedev, D. V.; Surzhik, M. A.; Sergeev, V. R.; Isaev-Ivanov, V. V. [National Research Center “Kurchatov Institute”, Konstantinov Petersburg Nuclear Physics Institute (Russian Federation)

    2016-01-15

    Glucoamylase from fungus Aspergillus awamori is glycoside hydrolase that catalyzes the hydrolysis of α-1,4- and α-1,6-glucosidic bonds in glucose polymers and oligomers. This glycoprotein consists of a catalytic domain and a starch-binding domain connected by an O-glycosylated polypeptide chain. The conformation of the linker, the relative arrangement of the domains, and the structure of the full-length enzyme are unknown. The structure of the recombinant glucoamylase GA1 was studied by molecular modelling and small-angle neutron scattering (SANS) methods. The experimental SANS data provide evidence that glucoamylase exists as a monomer in solution and contains a glycoside component, which makes a substantial contribution to the scattering. The model of full-length glucoamylase, which was calculated without taking into account the effect of glycosylation, is consistent with the experimental data and has a radius of gyration of 33.4 ± 0.6 Å.

  13. Assessment of the scatter correction procedures in single photon emission computed tomography imaging using simulation and clinical study

    Directory of Open Access Journals (Sweden)

    Mehravar Rafati

    2017-01-01

    Conclusion: The simulation and the clinical studies showed that the new approach could be better performance than DEW, TEW methods, according to values of the contrast, and the SNR for scatter correction.

  14. A new potential of π-nucleus scattering and its application to nuclear structure study using elastic scattering and charge exchange reactions

    International Nuclear Information System (INIS)

    Durand, Gerard.

    1974-01-01

    First the different theories used for studying pion-nucleus scattering and especially Glauber microscopic model and Kisslinger optical model are summarized. From the comparison of these two theories it was concluded that Kisslinger's was better for studying pion-nucleus scattering near the (3/2-3/2) resonance. The potential was developed, with a local corrective term, proposed by this author. This new term arises from taking into account correctly the Lorentz transformation from the pion-nucleon center of mass to the pion nucleus center of mass system. A coupled-channel formalism was developed allowing the study of pion-nucleus elastic scattering and also the study of single and double charge exchange reactions on nucleus with N>Z. The influence of the new term and the shape of nucleon densities on π- 12 C scattering was studied near 200MeV. It was found that at the nucleus surface the neutron density was larger than the proton density. On the other hand, a maximum of sensibility to the different nuclear parameters was found near 180MeV and for elastic scattering angles greater than 100 deg. The calculations of the total cross section for simple and double charge exchange for 13 C and 63 Cu yielded results simular to those of previous theories and showed the same discrepancy between theory and experiment in the resonance region [fr

  15. Studies of the phase transitions in UAs with neutron scattering

    International Nuclear Information System (INIS)

    Sinha, S.K.; Lander, G.H.; Shapiro, S.M.; Vogt, O.

    1980-01-01

    Uranium arsenide is known to order with the type-I antiferromagnetic (AF) structure at approx. 126 K, and exhibit a first-order transition to the type-IA AF structure at T/sub N//2. We have now reexamined these transitions with a single crystal. Above T/sub N/ UAs exhibits critical scattering suggesting a tendency to order with an incommensurate wavevector, but then suddenly orders with the AF-I structure. The analysis of the data shows the need to consider anisotropic exchange interactions of cubic symmetry between U moments

  16. Study of inelastic proton scattering at isobaric analog resonances

    International Nuclear Information System (INIS)

    Davis, S.L.

    1974-01-01

    Inelastic proton scattering at isobaric analog resonances (IAR's) was studied using the targets 138 Ba and 92 Mo. Differential cross sections and analyzing powers were measured at the 10.00, 10.63, 11.09, 11.45, and 11.70 MeV resonances in 138 Ba + p and at the 5.89, 6.09, and 6.55 MeV resonances in 92 Mo + p. In addition, a new measurement, the spin flip asymmetry, was developed. The experiment was performed by using a polarized beam to make spin flip measurements. Angular distributions for the spin flip probability and spin flip asymmetry were measured at all of the above energies except for the lowest three resonances in 138 Ba, where only the spin flip probability was measured. A DWBA code modified to include the coherent addition of resonance amplitudes was used to analyze the 138 Ba data. The partial widths extracted from this analysis were converted to expansion coefficients for parent states in 139 Ba. The coefficients were found to be in good agreement with unified model calculations. For 92 Mo, inelastic polarizations, deduced from the spin flip and spin flip asymmetry, were found to be large. Attempts using Hauser Feshbach theory to describe both the cross section and polarization data repeatedly failed for both the 6.55 and 5.87 MeV IAR's. This failure represents strong evidence that Hauser Feshbach theory is not valid when extended to describe scattering at an IAR. The 92 Mo data were analyzed using a reaction theory modified to include channel-channel correlations. This theory predicts that the enhanced compound scattering is identical to the resonance scattering. Good fits have been obtained with the use of this modified Hauser Feshbach theory. (U.S.)

  17. A neutron scattering study of triblock copolymer micelles

    Energy Technology Data Exchange (ETDEWEB)

    Gerstenberg, M.C.

    1997-11-01

    The thesis describes the neutron scattering experiments performed on poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) triblock copolymer micelles in aqueous solution. The studies concern the non-ionic triblock copolymer P85 which consists of two outer segments of 25 monomers of ethylene oxide attached to a central part of 40 monomers of propylene oxide. The amphiphilic character of P85 leads to formation of various structures in aqueous solution such as spherical micelles, rod-like structures, and a BCC liquid-crystal mesophase of spherical micelles. The present investigations are centered around the micellar structures. In the first part of this thesis a model for the micelle is developed for which an analytical scattering form factor can be calculated. The micelle is modeled as a solid sphere with tethered Gaussian chains. Good agreement was found between small-angle neutron scattering experiments and the form factor of the spherical P85 micelles. Above 60 deg. C some discrepancies were found between the model and the data which is possibly due to an elongation of the micelles. The second part focuses on the surface-induced ordering of the various micellar aggregates in the P85 concentration-temperature phase diagram. In the spherical micellar phase, neutron reflection measurements indicated a micellar ordering at the hydrophilic surface of quartz. Extensive modeling was performed based on a hard sphere description of the micellar interaction. By convolution of the distribution of hard spheres at a hard wall, obtained from Monte Carlo simulations, and the projected scattering length density of the micelle, a numerical expression was obtained which made it possible to fit the data. The hard-sphere-hard-wall model gave an excellent agreement in the bulk micellar phase. However, for higher concentrations (25 wt % P85) close to the transition from the micellar liquid into a micellar cubic phase, a discrepancy was found between the model and the

  18. A neutron scattering study of triblock copolymer micelles

    International Nuclear Information System (INIS)

    Gerstenberg, M.C.

    1997-11-01

    The thesis describes the neutron scattering experiments performed on poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) triblock copolymer micelles in aqueous solution. The studies concern the non-ionic triblock copolymer P85 which consists of two outer segments of 25 monomers of ethylene oxide attached to a central part of 40 monomers of propylene oxide. The amphiphilic character of P85 leads to formation of various structures in aqueous solution such as spherical micelles, rod-like structures, and a BCC liquid-crystal mesophase of spherical micelles. The present investigations are centered around the micellar structures. In the first part of this thesis a model for the micelle is developed for which an analytical scattering form factor can be calculated. The micelle is modeled as a solid sphere with tethered Gaussian chains. Good agreement was found between small-angle neutron scattering experiments and the form factor of the spherical P85 micelles. Above 60 deg. C some discrepancies were found between the model and the data which is possibly due to an elongation of the micelles. The second part focuses on the surface-induced ordering of the various micellar aggregates in the P85 concentration-temperature phase diagram. In the spherical micellar phase, neutron reflection measurements indicated a micellar ordering at the hydrophilic surface of quartz. Extensive modeling was performed based on a hard sphere description of the micellar interaction. By convolution of the distribution of hard spheres at a hard wall, obtained from Monte Carlo simulations, and the projected scattering length density of the micelle, a numerical expression was obtained which made it possible to fit the data. The hard-sphere-hard-wall model gave an excellent agreement in the bulk micellar phase. However, for higher concentrations (25 wt % P85) close to the transition from the micellar liquid into a micellar cubic phase, a discrepancy was found between the model and the

  19. Diffuse neutron scattering study of metallic interstitial solid solutions

    International Nuclear Information System (INIS)

    Barberis, P.

    1991-10-01

    We studied two interstitial solid solutions (Ni-C(1at%) and Nb-O(2at%) and two stabilized zirconia (ZrO2-CaO(13.6mol%) and ZrO2-Y2O3(9.6mol%) by elastic diffuse neutron scattering. We used polarized neutron scattering in the case of the ferromagnetic Ni-based sample, in order to determine the magnetic perturbation induced by the C atoms. Measurements were made on single crystals in the Laboratoire Leon Brillouin (CEA-CNRS, Saclay, France). An original algorithm to deconvolve time-of-flight spectra improved the separation between elastically and inelastically scattered intensities. In the case of metallic solutions, we used a simple non-linear model, assuming that interstitials are isolated and located in octahedral sites. Results are: - in both compounds, nearest neighbours are widely displaced away from the interstitial, while next nearest neighbours come slightly closer. - the large magnetic perturbation induced by carbon in Nickel decreases with increasing distance on the three first neighbour shells and is in good agreement with the total magnetization variation. - no chemical order between solute atoms could be evidenced. Stabilized zirconia exhibit a strong correlation between chemical order and the large displacements around vacancies and dopants. (Author). 132 refs., 38 figs., 13 tabs

  20. Study of human blood and hemocomponents irradiated by low angle x ray scattering (LAXS)

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Nivia G. Villela; Barroso, Regina C. [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Inst. de Fisica. Dept. de Fisica Aplicada e Termodinamica], e-mail: nitatag@gmail.com; Mota, Carla L.S.; Almeida, Andre P.; Azeredo, Soraia R.; Braz, Delson [Coordenacao dos Programas de Pos-graduacao em Engenharia (COPPE/UFRJ), RJ (Brazil). Lab. de Instrumentacao Nuclear], e-mail: delson@lin.ufrj.br

    2009-07-01

    Irradiation of blood and blood components is currently practiced in developed and in a few developing countries. The main purpose of this process is the prevention of graft versus host disease in immunodeficient patients. The Food and Drug Administration recommends a dose range of 15 Gy to 25 Gy for these blood components. When x-ray photons are scattered from biological samples, their angular distribution shows one or more peaks in the forward direction of scattering. These peaks are characteristic for the investigated samples. Due to its wide range of biological and medical applications, low-angle x-ray scattering has attracted the attention of many authors. Thus in this present work was studied the possible variations in scattering profiles due to the irradiation when the gender of patients was considered. Fresh blood specimens were obtained from volunteers using vacutainer tubes containing EDTA, at the Dr. Eliel Figueiredo Laboratory, Rio de Janeiro. All the samples were lyophilized for 48 hours in a freeze drier in order to remove the water. The scattering measurements were carried out in e-2e reflection geometry using a powder diffractometer Shimadzu XRD- 6000. The measured characterization parameters for LAXS were associated with epidemiological data (gender). The mean values of the different parameters were compared using the Students's t-test for each characterization parameters. The scattering profiles from plasma and formed elements are characterized by the presence of two peaks in the forward direction of scattering. For epidemiological data (gender) analyzed was not found significant changes in the mostly of characterization parameters (p>0.05). (author)

  1. Study of human blood and hemocomponents irradiated by low angle x ray scattering (LAXS)

    International Nuclear Information System (INIS)

    Pinto, Nivia G. Villela; Barroso, Regina C.; Mota, Carla L.S.; Almeida, Andre P.; Azeredo, Soraia R.; Braz, Delson

    2009-01-01

    Irradiation of blood and blood components is currently practiced in developed and in a few developing countries. The main purpose of this process is the prevention of graft versus host disease in immunodeficient patients. The Food and Drug Administration recommends a dose range of 15 Gy to 25 Gy for these blood components. When x-ray photons are scattered from biological samples, their angular distribution shows one or more peaks in the forward direction of scattering. These peaks are characteristic for the investigated samples. Due to its wide range of biological and medical applications, low-angle x-ray scattering has attracted the attention of many authors. Thus in this present work was studied the possible variations in scattering profiles due to the irradiation when the gender of patients was considered. Fresh blood specimens were obtained from volunteers using vacutainer tubes containing EDTA, at the Dr. Eliel Figueiredo Laboratory, Rio de Janeiro. All the samples were lyophilized for 48 hours in a freeze drier in order to remove the water. The scattering measurements were carried out in e-2e reflection geometry using a powder diffractometer Shimadzu XRD- 6000. The measured characterization parameters for LAXS were associated with epidemiological data (gender). The mean values of the different parameters were compared using the Students's t-test for each characterization parameters. The scattering profiles from plasma and formed elements are characterized by the presence of two peaks in the forward direction of scattering. For epidemiological data (gender) analyzed was not found significant changes in the mostly of characterization parameters (p>0.05). (author)

  2. Study of effective atomic number of breast tissues determined using the elastic to inelastic scattering ratio

    Energy Technology Data Exchange (ETDEWEB)

    Antoniassi, M.; Conceicao, A.L.C. [Departamento de Fisica e Matematica, Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil); Poletti, M.E., E-mail: poletti@ffclrp.usp.br [Departamento de Fisica e Matematica, Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Ribeirao Preto, Sao Paulo (Brazil)

    2011-10-01

    In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose and fibroglandular), benign (fibroadenoma) and malignant (ductal carcinoma) breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90{sup o} (x=0.99 A{sup -1}). A practical method using the area of Rayleigh and Compton scattering was used for determining the effective atomic number (Z{sub eff}) of the samples, being validated through measurements of several reference materials. The results show that there are differences in the distributions of Z{sub eff} of breast tissues, which are mainly related to the elemental composition of carbon (Z=6) and oxygen (Z=8) of each tissue type. The results suggest that is possible to use the method to characterize the breast tissues permitting study histological features of the breast tissues related to their elemental composition.

  3. Study of effective atomic number of breast tissues determined using the elastic to inelastic scattering ratio

    International Nuclear Information System (INIS)

    Antoniassi, M.; Conceicao, A.L.C.; Poletti, M.E.

    2011-01-01

    In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose and fibroglandular), benign (fibroadenoma) and malignant (ductal carcinoma) breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90 o (x=0.99 A -1 ). A practical method using the area of Rayleigh and Compton scattering was used for determining the effective atomic number (Z eff ) of the samples, being validated through measurements of several reference materials. The results show that there are differences in the distributions of Z eff of breast tissues, which are mainly related to the elemental composition of carbon (Z=6) and oxygen (Z=8) of each tissue type. The results suggest that is possible to use the method to characterize the breast tissues permitting study histological features of the breast tissues related to their elemental composition.

  4. Structural study of concentrated micelle-solutions of sodium octanoate by light scattering

    International Nuclear Information System (INIS)

    Hayoun, Marc

    1982-05-01

    Structural investigation of sodium octanoate (CH 3 -(CH 2 ) 6 -COONa) by light scattering has been made to study properties of concentrated aqueous micelle-solutions. From static light scattering data, the micellar weight and shape have been determined. The monomer aggregation number and the apparent micellar charge have been confirmed. Quasi-elastic light scattering, has been used to measure the effective diffusion coefficient as a function of the volume fraction. Extrapolation to the c.m.c. give the hydrodynamic radius of the micelles. At low micelle-concentration, strong exchange reaction between monomers and micelles affects the Brownian motion and resulting is an increase in the diffusion coefficient. The experimental data show a strong hydrodynamic contribution to S(q) (factor structure) and D(q) (effective diffusion coefficient) arising from hard spheres interactions with a large repulsive potential. (author) [fr

  5. Study of effective atomic number of breast tissues determined using the elastic to inelastic scattering ratio

    Science.gov (United States)

    Antoniassi, M.; Conceição, A. L. C.; Poletti, M. E.

    2011-10-01

    In this work we have measured Compton and Rayleigh scattering radiation from normal (adipose and fibroglandular), benign (fibroadenoma) and malignant (ductal carcinoma) breast tissues using a monoenergetic beam of 17.44 keV and a scattering angle of 90° ( x=0.99 Å -1). A practical method using the area of Rayleigh and Compton scattering was used for determining the effective atomic number ( Zeff) of the samples, being validated through measurements of several reference materials. The results show that there are differences in the distributions of Zeff of breast tissues, which are mainly related to the elemental composition of carbon ( Z=6) and oxygen ( Z=8) of each tissue type. The results suggest that is possible to use the method to characterize the breast tissues permitting study histological features of the breast tissues related to their elemental composition.

  6. Scatter correction method for x-ray CT using primary modulation: Phantom studies

    International Nuclear Information System (INIS)

    Gao Hewei; Fahrig, Rebecca; Bennett, N. Robert; Sun Mingshan; Star-Lack, Josh; Zhu Lei

    2010-01-01

    Purpose: Scatter correction is a major challenge in x-ray imaging using large area detectors. Recently, the authors proposed a promising scatter correction method for x-ray computed tomography (CT) using primary modulation. Proof of concept was previously illustrated by Monte Carlo simulations and physical experiments on a small phantom with a simple geometry. In this work, the authors provide a quantitative evaluation of the primary modulation technique and demonstrate its performance in applications where scatter correction is more challenging. Methods: The authors first analyze the potential errors of the estimated scatter in the primary modulation method. On two tabletop CT systems, the method is investigated using three phantoms: A Catphan(c)600 phantom, an anthropomorphic chest phantom, and the Catphan(c)600 phantom with two annuli. Two different primary modulators are also designed to show the impact of the modulator parameters on the scatter correction efficiency. The first is an aluminum modulator with a weak modulation and a low modulation frequency, and the second is a copper modulator with a strong modulation and a high modulation frequency. Results: On the Catphan(c)600 phantom in the first study, the method reduces the error of the CT number in the selected regions of interest (ROIs) from 371.4 to 21.9 Hounsfield units (HU); the contrast to noise ratio also increases from 10.9 to 19.2. On the anthropomorphic chest phantom in the second study, which represents a more difficult case due to the high scatter signals and object heterogeneity, the method reduces the error of the CT number from 327 to 19 HU in the selected ROIs and from 31.4% to 5.7% on the overall average. The third study is to investigate the impact of object size on the efficiency of our method. The scatter-to-primary ratio estimation error on the Catphan(c)600 phantom without any annulus (20 cm in diameter) is at the level of 0.04, it rises to 0.07 and 0.1 on the phantom with an

  7. Study of the multiple scattering effect in TEBENE using the Monte Carlo method

    International Nuclear Information System (INIS)

    Singkarat, Somsorn.

    1990-01-01

    The neutron time-of-flight and energy spectra, from the TEBENE set-up, have been calculated by a computer program using the Monte Carlo method. The neutron multiple scattering within the polyethylene scatterer ring is closely investigated. The results show that multiple scattering has a significant effect on the detected neutron yield. They also indicate that the thickness of the scatterer ring has to be carefully chosen. (author)

  8. Magnetic Dynamics of Fine Particles Studied by Inelastic Neutron Scattering

    DEFF Research Database (Denmark)

    Hansen, Mikkel Fougt; Bødker, Franz; Mørup, Steen

    2000-01-01

    We give an introduction to inelastic neutron scattering and the dynamic scattering function for magnetic nanoparticles. Differences between ferromagnetic and antiferromagnetic nanoparticles are discussed and we give a review of recent results on ferromagnetic Fe nanoparticles and canted antiferro......We give an introduction to inelastic neutron scattering and the dynamic scattering function for magnetic nanoparticles. Differences between ferromagnetic and antiferromagnetic nanoparticles are discussed and we give a review of recent results on ferromagnetic Fe nanoparticles and canted...

  9. Dynamics of liquid N2 studied by neutron inelastic scattering

    DEFF Research Database (Denmark)

    Pedersen, Karen Schou; Carneiro, Kim; Hansen, Flemming Yssing

    1982-01-01

    Neutron inelastic-scattering data from liquid N2 at wave-vector transfer κ between 0.18 and 2.1 Å-1 and temperatures ranging from T=65-77 K are presented. The data are corrected for the contribution from multiple scattering and incoherent scattering. The resulting dynamic structure factor S (κ,ω)...

  10. Reports of the study group for neutron scattering

    International Nuclear Information System (INIS)

    1982-01-01

    This report covers the activities from July 1980 to December 1981. Within this period, the project for reactor extension (including a thermal neutron source and a hall for the neutron guide), was worked out in detail. Like the Fritz-Haber Institute, the Institute for Crystallography of Tuebingen University decided to send a number of guest-scientists for studies at the Hahn-Meitner Institute on a permanent basis. The HMI also organized the 5th International Conference on Small-Angle Scattering, held in Berlin in October 1980. The scientific research work was mainly concerned with magnetic systems, molecular crystals, and the determination of electron densities. (orig.)

  11. Neutron scattering studies of pretransitional phenomena in structural phase transformations

    International Nuclear Information System (INIS)

    Shapiro, S.M.

    1979-03-01

    Materials exhibiting structural phase transformations are well known to possess pretransitional phenomena. Below the transition temperature, T/sub c/, an order parameter appears and the pretransitional effects are associated with the fluctuations of the order parameter. Neutron scattering techniques have proved invaluable in studying the temporal and spatial dependence of these fluctuations. SrTiO 3 is the prototypical example of a structural phase transformation exhibiting features observable in other transformations such as martensitic and order-disorder. The experimental evolution of the understanding of the phase transformation in SrTiO 3 will be reviewed and the features observed will be shown to typify other systems

  12. Kartini Research Reactor prospective studies for neutron scattering application

    International Nuclear Information System (INIS)

    Widarto

    1999-01-01

    The Kartini Research Reactor (KRR) is located in Yogyakarta Nuclear Research Center, Yogyakarta - Indonesia. The reactor is operated for 100 kW thermal power used for research, experiments and training of nuclear technology. There are 4 beam ports and 1 column thermal are available at the reactor. Those beam ports have thermal neutron flux around 10 7 n/cm 2 s each other and used for sub critical assembly, neutron radiography studies and Neutron Activation Analysis (NAA). Design of neutron collimator has been done for piercing radial beam port and the calculation result of collimated neutron flux is around 10 9 n/cm 2 s. This paper describes experiment facilities and parameters of the Kartini research reactor, and further more the prospective studies for neutron scattering application. The purpose of this paper is to optimize in utilization of the beam ports facilities and enhance the manpower specialty. The special characteristic of the beam ports and preliminary studies, pre activities regarding with neutron scattering studies for KKR is presented. (author)

  13. Neutron scattering study of Ce3Au3Sb4

    International Nuclear Information System (INIS)

    Kasaya, Mitsuo; Katoh, Kenichi; Kohgi, Masahumi; Osakabe, Toyotaka

    1993-01-01

    Rare-earth compounds with an Y 3 Au 3 Sb 4 -type crystal structure are semiconductors or semi-metals. Among them, Ce 3 Au 3 Sb 4 is a semiconductor with an activation energy of about 640 K and shows no magnetic order down to 1.5 K. The magnetic part of the specific heat for Ce 3 Au 3 Sb 4 obtained by subtracting the value for La 3 Au 3 Sb 4 from the total specific heat of Ce 3 Au 3 Sb 4 shows a broad peak at around 10 K, the origin of which is well explained by the crystalline-field splitting determined by neutron scattering. (author)

  14. Comprehensive study of observables in Compton scattering on the nucleon

    Science.gov (United States)

    Grießhammer, Harald W.; McGovern, Judith A.; Phillips, Daniel R.

    2018-03-01

    We present an analysis of 13 observables in Compton scattering on the proton. Cross sections, asymmetries with polarised beam and/or targets, and polarisation-transfer observables are investigated for energies up to the Δ(1232) resonance to determine their sensitivity to the proton's dipole scalar and spin polarisabilities. The Chiral Effective Field Theory Compton amplitude we use is complete at N4LO, O(e2δ4), for photon energies ω˜ m_{π}, and so has an accuracy of a few per cent there. At photon energies in the resonance region, it is complete at NLO, O(e2δ0), and so its accuracy there is about 20%. We find that for energies from pion-production threshold to about 250 MeV, multiple asymmetries have significant sensitivity to presently ill-determined combinations of proton spin polarisabilities. We also argue that the broad outcomes of this analysis will be replicated in complementary theoretical approaches, e.g., dispersion relations. Finally, we show that below the pion-production threshold, 6 observables suffice to reconstruct the Compton amplitude, and above it 11 are required. Although not necessary for polarisability extractions, this opens the possibility to perform "complete" Compton-scattering experiments. An interactive Mathematica notebook, including results for the neutron, is available from judith.mcgovern@manchester.ac.uk.

  15. [Neutron scatter studies of chromatin structure related to function

    International Nuclear Information System (INIS)

    Bradbury, E.M.

    1990-01-01

    This study is concerned with the application of neutron scatter techniques to the different structural states of nucleosomes and chromatin with the long term objective of understanding how the enormous lengths of DNA are folded into chromosomes. Micrococcal nuclease digestion kinetics have defined two subnucleosome particles; the chromatosome with 168 bp DNA, the histone octamer and one H1 and the nucleosome core particle with 146 bp DNA and the histone octamer. As will be discussed, the structure of the 146 bp DNA core particle is known in solution at low resolution from neutron scatter studies and in crystals. Based on this structure, the authors have a working model for the chromatosome and the mode of binding of H1. In order to define the structure of the nucleosome and also the different orders of chromatin structures they need to know the paths of DNA that link nucleosomes and the factors associated with chromosome functions that act on those DNA paths. The major region for this situation is the inherent variabilities in nucleosome DNA sequences, in the histone subtypes and their states of chemical modification and in the precise locations of nucleosomes. Such variabilities obscure the underlying principles that govern the packaging of DNA into the different structural states of nucleosomes and chromatin. The only way to elucidate these principles is to study the structures of nucleosomes and oligonucleosomes that are fully defined. They have largely achieved these objectives

  16. Characteristics of angular cross correlations studied by light scattering from two-dimensional microsphere films

    Science.gov (United States)

    Schroer, M. A.; Gutt, C.; Grübel, G.

    2014-07-01

    Recently the analysis of scattering patterns by angular cross-correlation analysis (CCA) was introduced to reveal the orientational order in disordered samples with special focus to future applications on x-ray free-electron laser facilities. We apply this CCA approach to ultra-small-angle light-scattering data obtained from two-dimensional monolayers of microspheres. The films were studied in addition by optical microscopy. This combined approach allows to calculate the cross-correlations of the scattering patterns, characterized by the orientational correlation function Ψl(q), as well as to obtain the real-space structure of the monolayers. We show that CCA is sensitive to the orientational order of monolayers formed by the microspheres which are not directly visible from the scattering patterns. By mixing microspheres of different radii the sizes of ordered monolayer domains is reduced. For these samples it is shown that Ψl(q) quantitatively describes the degree of hexagonal order of the two-dimensional films. The experimental CCA results are compared with calculations based on the microscopy images. Both techniques show qualitatively similar features. Differences can be attributed to the wave-front distortion of the laser beam in the experiment. This effect is discussed by investigating the effect of different wave fronts on the cross-correlation analysis results. The so-determined characteristics of the cross-correlation analysis will be also relevant for future x-ray-based studies.

  17. Quarkonia propagation in QGP: study of elastic and inelastic scattering processes

    International Nuclear Information System (INIS)

    Berrehrah, H; Aichelin, J; Gossiaux, P B

    2011-01-01

    We propose to study the quarkonia (φ) propagation in the QGP. We are especially interested in the elastic and inelastic scattering process of these quarkonia in the medium. We developed the Bethe-Salpeter formalism to calculate the elastic cross section (σ elas ) for φ - gluon/hadron. Results obtained in this work show that σ elas (φ - gluon/hadron) might have non negligible effects in the study of Q Q-bar propagation.

  18. Study of multiple scattering effects in heavy ion RBS

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Z; O` Connor, D J [Newcastle Univ., NSW (Australia). Dept. of Physics

    1997-12-31

    Multiple scattering effect is normally neglected in conventional Rutherford Backscattering (RBS) analysis. The backscattered particle yield normally agrees well with the theory based on the single scattering model. However, when heavy incident ions are used such as in heavy ion Rutherford backscattering (HIRBS), or the incident ion energy is reduced, multiple scattering effect starts to play a role in the analysis. In this paper, the experimental data of 6MeV C ions backscattered from a Au target are presented. In measured time of flight spectrum a small step in front of the Au high energy edge is observed. The high energy edge of the step is about 3.4 ns ahead of the Au signal which corresponds to an energy {approx} 300 keV higher than the 135 degree single scattering energy. This value coincides with the double scattering energy of C ion undergoes two consecutive 67.5 degree scattering. Efforts made to investigate the origin of the high energy step observed lead to an Monte Carlo simulation aimed to reproduce the experimental spectrum on computer. As a large angle scattering event is a rare event, two consecutive large angle scattering is extremely hard to reproduce in a random simulation process. Thus, the simulation has not found a particle scattering into 130-140 deg with an energy higher than the single scattering energy. Obviously faster algorithms and a better physical model are necessary for a successful simulation. 16 refs., 3 figs.

  19. Study of multiple scattering effects in heavy ion RBS

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Z.; O`Connor, D.J. [Newcastle Univ., NSW (Australia). Dept. of Physics

    1996-12-31

    Multiple scattering effect is normally neglected in conventional Rutherford Backscattering (RBS) analysis. The backscattered particle yield normally agrees well with the theory based on the single scattering model. However, when heavy incident ions are used such as in heavy ion Rutherford backscattering (HIRBS), or the incident ion energy is reduced, multiple scattering effect starts to play a role in the analysis. In this paper, the experimental data of 6MeV C ions backscattered from a Au target are presented. In measured time of flight spectrum a small step in front of the Au high energy edge is observed. The high energy edge of the step is about 3.4 ns ahead of the Au signal which corresponds to an energy {approx} 300 keV higher than the 135 degree single scattering energy. This value coincides with the double scattering energy of C ion undergoes two consecutive 67.5 degree scattering. Efforts made to investigate the origin of the high energy step observed lead to an Monte Carlo simulation aimed to reproduce the experimental spectrum on computer. As a large angle scattering event is a rare event, two consecutive large angle scattering is extremely hard to reproduce in a random simulation process. Thus, the simulation has not found a particle scattering into 130-140 deg with an energy higher than the single scattering energy. Obviously faster algorithms and a better physical model are necessary for a successful simulation. 16 refs., 3 figs.

  20. Magnetic anisotropy and neutron scattering studies of some rare earth metals

    International Nuclear Information System (INIS)

    Day, R.

    1978-08-01

    The thesis is concerned with magnetic anisotropy of dysprosium and alloys of gadolinium: yttrium, and also neutron scattering studies of dysprosium. The experiments are discussed under the topic headings: magnetic anisotropy, rare earths, torque measurements, elastic neutron scattering, inelastic neutron scattering, dysprosium measurements, and results for the gadolinium: yttrium alloys. (U.K.)

  1. A study on basic theory for CDCC method for three-body model of deuteron scattering

    International Nuclear Information System (INIS)

    Kawai, Mitsuji

    1988-01-01

    Recent studies have revealed that the CDCC method is valid for treating the decomposition process involved in deuteron scattering on the basis of a three-body model. However, theoretical support has not been developed for this method. The present study is aimed at determining whether a solution by the CDCC method can be obtained 'correctly' from a 'realistic' model Hamiltonian for deuteron scattering. Some researchers have recently pointed out that there are some problems with the conventional CDCC calculation procedure in view of the general scattering theory. These problems are associated with asymptotic froms of the wave functions, convergence of calculations, and boundary conditions. Considerations show that the problem with asymptotic forms of the wave function is not a fatal defect, though some compromise is necessary. The problem with the convergence of calculations is not very serious either. Discussions are made of the handling of boundary conditions. Thus, the present study indicates that the CDCC method can be applied satisfactorily to actual deuteron scattering, and that the model wave function for the CDCC method is consistent with the model Hamiltonian. (Nogami, K.)

  2. Study of final states in deep inelastic muon scattering

    CERN Multimedia

    2002-01-01

    The aim of this experiment is to study the different possible final states in deep inelastic muon scattering from hydrogen in connection with the detection of the scattered muon in a forward spectrometer (Experiment NA2).\\\\ \\\\ A vertex detector will be used which extends the hadron detection capabilities into the backward hemisphere of the centre-of-mass system. Particle momenta can be measured down to 200 MeV/c in a vertex magnet, which contains a streamer chamber (SC Particle identification will be done in a series of wide angle Čerenkov counters (C$_{0}$, C$_{1}$) and at low momenta in time-of-flight counter hodoscopes (F1-F4). An 8-plane module of MWPC chambers (PV) will be used in conjunction with the streamer chamber and the drift chambers WV1 and WV2 and WV3. \\\\ \\\\ The vertex magnet is a C magnet with circular pole tips of 2 m diameter and 1 m gap width. The central magnetic field will be 1.5 T. The streamer chamber (2m x 1.2m x 0.72m) will contain a 1 m liquid H$_{2}$ target.\\\\ \\\\ As a natural extens...

  3. A study of W W scattering at the LHC

    CERN Document Server

    Nauyock, Farahnaaz

    2004-01-01

    This thesis presents a study of scattering at the LHC, a proton-proton collider being built at CERN and due to start its first run in 2007. The case where no new particles are discovered before the start of the LHC is analysed. The elastic scattering of is considered and the semileptonic 1 decay channels of the bosons are investigated. Signals and backgrounds are simulated using Atlfast, a fast simulation programme for the ATLAS experiment. This specific channel causes violation of unitarity at 1.2 TeV. Therefore, unitarisation is performed and this leads to different resonance scenarios, five of which are investigated. The final signal to background ratio after applying various kinematic cuts on events is greater than one for all the five scenarios. A comparison between the algorithm and cone algorithm is also performed to find out which jet-finding analysis yields a better signal to background ratio. The algorithm proves very efficient in reducing the background by an approximate factor of 1.5 better than t...

  4. A study on the scattered dose in portable chest radiography

    International Nuclear Information System (INIS)

    Ahn, Bong Seon; Lee, Hwan Hyung

    2000-01-01

    The purpose of this study is to survey the present status of portable radiography and the result of free space scattered dose rate when taking a radiography at the general hospital or the university hospital in Taejon city. The results were as follows; The number of cases using portable radiography for three years increased to averages 16.2%, 7.7% per year from January 1st in 1996 to December 31st in 1998. The average of distance of adjacent patients was 219.1 cm at the ward. For portable chest radiography, the free space scattered dose rate was 10.5 mSv/hr at 50 cm distance, 1.8 mSv/hr at 100 cm distance, and 0.2 mSv/hr at 200 cm distance. Therefore, in case of portable chest radiography at the ward, the average of distance of adjacent patients is 219.1 cm, so it dose not have influence on the adjacent patient. But during the portable radiography, a guardian who is close to the patient, doctor, nurse and radiologic technologists has to set up the shield to prevent from the unnecessary radiation or the distance should be as great as possible from the mobile X-ray equipment

  5. Neutron scatter studies of chromatin structures related to functions

    International Nuclear Information System (INIS)

    Bradbury, E.M.

    1992-01-01

    Despite of setbacks in the lack of neutrons for the proposed We have made considerable progress in chromatin reconstitution with the VLR histone H1/H5 and in understanding the dynamics of nucleosomes. A ferromagnetic fluid was developed to align biological molecules for structural studies using small-angle-neutron-scattering. We have also identified and characterized an intrinsically bent DNA region flanking the RNA polymerase I binding site of the ribosomal RNA gene in Physarum Polycephalum. Finally projects in progress are in the areas of studying the interatctions of histone H4 amino-terminus peptide 1-23 and acetylated 1-23 peptide with DNA using thermal denaturation; study of GGAAT repeats found in human centromeres using high resolution Nuclear magnetic Resonance and nuclease sentivity assay; and the role of histones and other sperm specific proteins with sperm chromatin

  6. Neutron scatter studies of chromatin structures related to functions

    International Nuclear Information System (INIS)

    Bradbury, E.M.

    1992-01-01

    We have made considerable progress in chromatin reconstitution with very lysine rich histone H1/H5 and in understanding the dynamics of nucleosomes. A ferromagnetic fluid was developed to align biological molecules for structural studies using small-angle-neutron-scattering. We have also identified and characterized in intrinsically bent DNA region flaking the RNA polymerase I binding site of the ribosomal RNA gene in Physarum Polycephalum. Finally projects in progress are in the areas of studying the interactions of histone H4 amino-terminus peptide 1-23 and acetylated 1-23 peptide with DNA using thermal denaturation; study of GGAAT repeats found in human centromeres using high resolution Nuclear Magnetic Resonance and nuclease sentivity assay; and the role of histones and other sperm specific proteins with sperm chromatin

  7. Resonant x-ray scattering in manganites: study of the orbital degree of freedom

    International Nuclear Information System (INIS)

    Ishihara, Sumio; Maekawa, Sadamichi

    2002-01-01

    The orbital degree of freedom of electrons and its interplay with spin, charge and lattice degrees of freedom are some of the central issues in colossal magnetoresistive manganites. The orbital degree of freedom has until recently remained hidden, since it does not couple directly to most experimental probes. Development of synchrotron light sources has changed the situation; by the resonant x-ray scattering (RXS) technique the orbital ordering has successfully been observed. In this article, we review progress in the recent studies of RXS in manganites. We start with a detailed review of the RXS experiments applied to the orbital-ordered manganites and other correlated electron systems. We derive the scattering cross section of RXS, where the tensor character of the atomic scattering factor (ASF) with respect to the x-ray polarization is stressed. Microscopic mechanisms of the anisotropic tensor character of the ASF are introduced and numerical results of the ASF and the scattering intensity are presented. The azimuthal angle scan is a unique experimental method to identify RXS from the orbital degree of freedom. A theory of the azimuthal angle and polarization dependence of the RXS intensity is presented. The theoretical results show good agreement with the experiments in manganites. Apart from the microscopic description of the ASF, a theoretical framework of RXS to relate directly to the 3d orbital is presented. The scattering cross section is represented by the correlation function of the pseudo-spin operator for the orbital degree of freedom. A theory is extended to the resonant inelastic x-ray scattering and methods to observe excitations of the orbital degree of freedom are proposed. (author)

  8. Small-angle neutron scattering studies of the template-mediated crystallization of ZSM-5 type zeolite

    International Nuclear Information System (INIS)

    Iton, L.E.; Brun, T.O.; Epperson, J.E.

    1988-03-01

    Small-angle neutron scattering is a useful new approach to the study of zeolite crystallization from aluminosilicate gels and the action of template molecules. It has been applied to gels for synthesis of zeolite ZSM-5 using tetrapropylammonium ions as templates where the scattering length densities of the gel particles and their texture were determined using contrast variation methods. Gels formulated from soluble silicate incorporate template molecules promptly into an amorphous ''embryonic'' structure and crystallization ensues via a solid hydrogel transformation mechanism. Gels formulated from colloidal silica show different scattering behavior, and a liquid phase transport mechanism is inferred. 8 refs., 4 figs., 2 tabs

  9. A study of photoluminescence and micro-Raman scattering in C-implanted GaN

    International Nuclear Information System (INIS)

    Zhang Limin; Zhang Xiaodong; Liu Zhengmin

    2010-01-01

    GaN samples (no yellow luminescence) in their as-grown states were implanted with 10 13 -10 17 C ions/cm 2 and studied by photoluminescence spectra and micro-Raman scattering spectra. The photoluminescence study showed that yellow luminescence were produced in the C-implanted GaN after 950 degree C annealing, and the peaks of the near band edge emissions showed blue-shifts after C implantation. The Raman measurements indicated that the stresses in GaN films did not change after C implantation. The samples implanted with 10 15 cm -2 carbon ions had the Raman peak at 300 cm -1 , which is associated to the disorder-activated Raman scattering. However, further increasing the implantation dose resulted decreased intensity of the 300 cm -1 peak, due to the ion beam current increase with the implantation dose. (authors)

  10. Study of the threshold anomaly in the scattering of polarized 7Li from 208Pb

    International Nuclear Information System (INIS)

    Martel, I.; Gomez-Camacho, J.; Blyth, C.O.; Davis, N.J.; Rusek, K.; Connell, K.A.; Lilley, J.S.; Bailey, M.W.

    1995-01-01

    Experimental data on elastic and inelastic analysing powers T 20 and inelastic cross sections for the scattering of polarized 7 Li from a 208 Pb target are presented. The experimental data are analyzed with DWBA and coupled channels calculations, which show the sensitivity of the experimental data to the real and imaginary parts of the nuclear transition form factor. This study reveals the existence of a threshold anomaly for the transition terms of the interaction. ((orig.))

  11. Anomalous vibrational modes in acetanilide as studied by inelastic neutron scattering

    Science.gov (United States)

    Barthes, Mariette; Eckert, Juegen; Johnson, Susanna W.; Moret, Jacques; Swanson, Basil I.; Unkefer, Clifford J.

    1992-10-01

    A study of the anomalous modes in acetanilide and five deuterated derivatives by incoherent inelastic neutron scattering is reported. These data show that the dynamics of the amide and methyl groups influence each other. In addition, the anomalous temperature behaviour of the NH out-of-plane bending mode is confirmed. These observations suggest that the self-trapping mechanism in ACN may be more complex than hitherto assumed.

  12. Comparative Compton scattering studies in Cu2O and Ag2O

    International Nuclear Information System (INIS)

    Bandyopadhyay, S.; Chatterjee, A.K.; Saha, S.K.; Chatterjee, A.

    1994-01-01

    Compton scattering studies in polycrystalline Cu 2 O and Ag 2 O with 59.54 keV γ radiation are reported. A comparison has been made between the valance Compton profiles of these two components scaled to lattice momentum by normalizing them to equal electron density for outer valence electrons, and this comparison shows some differences between the bonding characters of Cu 2 O and Ag 2 O. (author)

  13. Experimental study on stimulated scattering of ZnO nanospheres dispersed in water

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Jiulin, E-mail: hyq1304@126.com; Wu, Haopeng [Nanchang Hangkong University, Jiangxi Engineering Laboratory for Optoelectronics Testing Technology (China); Yan, Feng; Yang, Junjie [Nanchang Hangkong University, School of Measuring and Optical Engineering (China); He, Xingdao, E-mail: xingdaohe@126.com [Nanchang Hangkong University, Jiangxi Engineering Laboratory for Optoelectronics Testing Technology (China)

    2016-01-15

    The backward stimulated scattering (BSS) from ZnO nanospheres dispersed in water has been investigated experimentally by employing a Nd:YAG pulse laser with ∼532 nm wavelength and ∼8 ns pulse width as the pump laser source. The present results show that the BSS effect is uniquely and unequivocally different compared to other known stimulated scattering, such as stimulated Rayleigh scattering, stimulated Brillouin scattering, and stimulated Raman scattering, and it displays the characteristics of no frequency shift and threshold dependence on initial spontaneous Mie scattering seed source. These can be understood by means of the Mie scattering theory and a laser-induced stationary Bragg grating model.

  14. Project study of a small-angle neutron scattering apparatus

    International Nuclear Information System (INIS)

    Schedler, E.; Pollet, J.L.

    1979-03-01

    This design study deals with the set up of a low angle scattering apparatus in the HMI reactor hall in Berlin. The experiences of other institutes with facilities of a similar type, - especially with D11 and D17 of the ILL in Grenoble, the set up the KFA in Juelich and of the PTB in Braunschweig -, are included to a large extend. The aim of this paper is - to define the necessary boundary conditions for the construction (including: installation of a cold source, the beam line, the neutron guide pipe and an extention of the reactor hall), -to determine the properties of the planned apparatus, especially in comparison with D11, probably the most versatile instrument, - to make desitions for the design of the components, - to work out the detailed drawings for construction - to estimate the costs and the time necessary for construction, if industrial manufacturers set up the project. (orig.) [de

  15. Neutron scattering studies of molecular conformations in liquid crystal polymers

    Science.gov (United States)

    Noirez, L.; Moussa, F.; Cotton, J. P.; Keller, P.; Pépy, G.

    1991-03-01

    A comblike liquid crystal polymer (LPC) is a polymer on which mesogenic molecules have been grafted. It exhibits a succession of liquid crystal phases. Usually the equilibrium conformation of an ordinary polymeric chain corresponds to a maximum entropy, i.e., to an isotropic spherical coil. How does the backbone of a LCP behave in the nematic and smectic field? Small-angle neutron scattering may answer this question. Such measurements are presented here on four different polymers as a function of temperature. An anisotropy of the backbone conformation is found in all these studied compounds, much more pronounced in the smectic phase than in the nematic phase: the backbone spreads more or less perpendicularly to its hanging cores. A comparison with existing theories and a discussion of these results is outlined.

  16. The small angle neutron scattering study on the segmented polyurethane

    International Nuclear Information System (INIS)

    Sudirman; Gunawan; Prasetyo, S.M.; Karo Karo, A.; Lahagu, I.M.; Darwinto, Tri

    1999-01-01

    The distance between hard segment (HS) and soft segment (SS) of segmented polyurethane have been determined using the Small Angle Neutron Scattering (SANS) technique. The segmented Polyurethanes (SPU) are linear multiblock copolymers, which include elastomer thermoplastic. SPU consist of hard segment and soft segment, each has tendency to make a group with similar type to form a domain. The soft segments used were polypropylene glycol (PPG) and 4,4 diphenylmethane diisocyanate (MDI), while l,4 butanediol (BD) was used as hard segment. The characteristic of SPU depends on its phase structure which is affected by several factors, such as type of chemical formula and the composition of the HS and SS, solvent as well as the synthesizing process. The samples used in this study were SPU56 and SPU68. Based on the appearance of SANS profile, it was obtained that domain distances are 12.32 nm for the SPU56 and 19 nm for the SPU68. (author)

  17. Study of α-16O scattering by orthogonality condition models

    International Nuclear Information System (INIS)

    Breitschaft, A.M.; Canto, L.F.; Schechter, H.

    1983-01-01

    The use of approximate microscopic theories in α- 16 O scattering is investigated. The Orthogonality Condition Model (OCM) with both the direct potential of the Resonating Group Method (RMG) and with an effective local potential, V sub(eff), derived from Kernels of Generator Coordinate Method (GCM) is employed to study collisions at CM energies up to 30 MeV, for all relevant partial waves. Although the predictions of the OCM are consistent with 'exact' RGM results in both cases, the nuclear phase-shifts obtained with the effective potential are better. The presence of ambiguities in the derivation of V sub(eff) is noticed. The nature of such ambiguities is discussed. (Author) [pt

  18. Study of α-16O scattering by orthogonality condition models

    International Nuclear Information System (INIS)

    Breitschaft, A.M.; Canto, L.F.; Schechter, H.

    1982-01-01

    The use of approximate microscopic theories in α- 16 O scattering is investigated. The Orthogonality Condition Model (OCM) with the direct potential of the Resonating Group Method (RGM) and with an effective local potential V sub(eff') derived from Kernels of the Generator Coordinate Method (GCM) is employed to study collisions at CM energies up to 30 MeV, for all relevant partial waves. Although the predictions of the OCM are consistent with 'exact' RGM results in both cases, the nuclear phase-shifts obtained with the effective potential are better. It is noticed the presence of ambiguities in the derivation of V sub(eff'). The nature of such ambiguities is discussed. (Author) [pt

  19. Study of double scattering effect in antiproton--deuteron annihilation

    International Nuclear Information System (INIS)

    Zemany, P.D.

    1975-01-01

    The double scattering process in the deuteron is investigated for the reaction anti pd → p/sub s/ + mesons. About 30 percent of the apparent anti pn annihilations are involved in double scattering. A model which describes the properties of protons emerging from apparent anti pn annihilations is presented

  20. Study of electromagnetic wave scattering by periodic density irregularities in plasma

    International Nuclear Information System (INIS)

    Lyle, R.; Kuo, S.P.; Huang, J.

    1995-01-01

    A quasi-particle approach is used to formulate wave propagation and scattering in a periodically structured plasma. The theory is then applied to study the effect of bottomside sinusoidal (BSS) irregularities on the propagation of beacon satellites signals through the ionosphere. In this approach, the radio wave is treated as a distribution of quasi-particles described by a Wigner distribution function governed by a transport equation. The irregularities providing the collisional effect are modeled as a two dimensional density modulation on a uniform background plasma. The present work generalizes the previous work by including the spectral bandwidth (Δk/k) effect of the spatially periodic irregularities on the transionospheric signal propagation. The collision of quasi-particles with the irregularities modifies the quasi-particle distribution and give rise to the wave scattering phenomenon. The multiple scattering process is generally considered in this deterministic analysis of radio wave scattering off the ionospheric density irregularities. The analysis shows that this two dimensional density grating effectively modulates the intensity of the beacon satellite signals. This spatial modulation of the wave intensity is converted into time modulation due to the drift of the ionospheric irregularities, which then results in the scintillation of the beacon satellite signals

  1. Nucleon-nucleon scattering studies at small angles at COSY-ANKE

    Energy Technology Data Exchange (ETDEWEB)

    Bagdasarian, Zara [Forschungszentrum Juelich, Juelich (Germany); Tbilisi State University, Tbilisi (Georgia); Collaboration: ANKE-Collaboration

    2015-07-01

    The most accepted approach to describe nucleon-nucleon (NN) interaction is the partial wave analysis (PWA). The SAID database and analysis program comprise various experimental observables at different energies over the full angular range and express them in the partial waves. The goal of the experiments held at COSY-Juelich is to provide SAID with new valuable measurements. Scattering data was taken at small angles for six beam energies between 0.8 and 2.4 GeV with polarized proton beam incident on both proton and deuteron unpolarized targets using the ANKE spectrometer. First, the results of the proton-proton (pp) scattering analyzing power and cross section are presented. While pp data closes a very important gap at small angles in the database, proton-neutron (pn) data is a crucial contribution to the almost non-explored pn database above 800 MeV. Therefore, the talk will mainly concentrate on the proton-deuteron (pd) scattering studies, which includes the overview of the older COSY experiments with polarized deuteron beam, and the abovementioned new experiment with polarized proton beam and unpolarized deuteron target. The presentation will show the most recent results of the analyzing powers of pd elastic and pn scattering.

  2. Study on proton spin flip in scattering by Ti and Fe nuclei

    International Nuclear Information System (INIS)

    Korbetskij, E.V.; Prokopenko, V.S.; Sklyarenko, V.D.; Chernievskij, V.K.; Shustov, A.V.

    1981-01-01

    Spin-orbital effects and mechanisms of inelastic scattering of protons with energy of 6.9 MeV by sup(14, 48)Ti and sup(54, 56, 58)Fe are studied by the analysis of experimental results within the framework of the method of coupled channels. Simultaneously angular dependences of cross sections of elastic and inelastic (two first 2 + levels) scatterings and a probability of spin flip of proton at inelastic scattering are analysed. Experimental data were used for analysis, obtained in the given work, as well as the data published earlier. Targets are used in experiment which are in the form of self-sustaining fine (1-2 mg cm -2 ) films, enriched with corresponding isotope. Cross section determination error is 8% in the average. Obtained angular dependences of spin flip probability for sup(54, 56)Fe at Esub(p)=6.9 MeV are very similar in form and close in value to analogous at Esub(p)= 6 MeV, and differ greatly for 56 Fe at Esub(p)=5.88 MeV. Angular distributions of spin flip probabilities of protons from sup(54, 56)Fe (ppsub(1)) reaction at energies of 10, 11 and 12 MeV show the sufficient energy dependence of their shape and value. Experimental data are described satisfactorily witohin the framework of the cupled channel method namely - differential cross sections of elastic and inelastic scattering and angular dependences of the probability of spin flip at the interaction of protons with 6.9 MeV energy with sup(46, 48)Ti and sup(54, 56, 58)Fe nuclei. Difficulties, appearing in the description of cross sections of elastic scattering in case of sup(46, 48)Ti and of inelastic one for 56 Fe show that indirect processes are of importance in the present energy range and they should be taken into consideration [ru

  3. A neutron scattering study on the stability of trehalose mycolates under thermal stress

    Science.gov (United States)

    Migliardo, F.; Salmeron, C.; Bayan, N.

    2013-10-01

    The present paper is focused on the study of the dynamics of mycolic acids, which are fundamental components of the outer membrane (mycomembrane) of Mycobacterium tuberculosis. An elastic neutron scattering study of mycolic acid/H2O and lecithin/H2O mixtures as a function of temperature and exchanged wavevector Q has been carried out. This study provides an effective way for characterizing the dynamical properties, furnishing a set of parameters characterizing the different flexibility and rigidity of the investigated lipids. The behavior of the elastically scattered intensity profiles and the derived mean square displacements as a function of temperature shows a more marked temperature dependence for lecithin lipids in comparison with mycolic acids, so revealing a higher thermal stability of these latter. These findings could be useful for understanding the dynamics-function relation in the mycomembrane and then to relate it to the low permeability and high resistance of mycobacteria to many antibiotics.

  4. Rayleigh to Compton ratio scatter tomography applied to breast cancer diagnosis: A preliminary computational study

    International Nuclear Information System (INIS)

    Antoniassi, M.; Conceição, A.L.C.; Poletti, M.E.

    2014-01-01

    In the present work, a tomographic technique based on Rayleigh to Compton scattering ratio (R/C) was studied using computational simulation in order to assess its application to breast cancer diagnosis. In this preliminary study, some parameters that affect the image quality were evaluated, such as: (i) energy beam, (ii) size and glandularity of the breast, and (iii) statistical count noise. The results showed that the R/C contrast increases with increasing photon energy and decreases with increasing glandularity of the sample. The statistical noise showed to be a significant parameter, although the quality of the obtained images was acceptable for a considerable range of noise level. The preliminary results suggest that the R/C tomographic technique has a potential of being applied as a complementary tool in the breast cancer diagnostic. - Highlights: ► A tomographic technique based on Rayleigh to Compton scattering ratio is proposed in order to study breast tissues. ► The Rayleigh to Compton scattering ratio technique is compared with conventional transmission technique. ► The influence of experimental parameters (energy, sample, detection system) is studied

  5. A neutron scattering study on the stability of trehalose mycolates under thermal stress

    Energy Technology Data Exchange (ETDEWEB)

    Migliardo, F., E-mail: fmigliardo@unime.it [Department of Physics, University of Messina, Viale D’Alcontres 31, 98166 Messina (Italy); Salmeron, C.; Bayan, N. [Laboratoire de Microbiologie Moléculaire et Cellulaire, IBBMC, Bat 430, Université de Paris Sud XI, 15 rue Georges Clémenceau, 91405 Orsay Cedex (France)

    2013-10-16

    Highlights: ► Neutron scattering measurements have been performed on mycolate water mixtures. ► A comparison with lecithin lipid water mixtures has been carried out. ► Mycolates show a lower mobility and flexibility compared to lecithin. ► The observed peculiarities of mycolic acids could be ascribed to trehalose. ► The results could justify the high resistance to thermal stress of mycobacteria. - Abstract: The present paper is focused on the study of the dynamics of mycolic acids, which are fundamental components of the outer membrane (mycomembrane) of Mycobacterium tuberculosis. An elastic neutron scattering study of mycolic acid/H{sub 2}O and lecithin/H{sub 2}O mixtures as a function of temperature and exchanged wavevector Q has been carried out. This study provides an effective way for characterizing the dynamical properties, furnishing a set of parameters characterizing the different flexibility and rigidity of the investigated lipids. The behavior of the elastically scattered intensity profiles and the derived mean square displacements as a function of temperature shows a more marked temperature dependence for lecithin lipids in comparison with mycolic acids, so revealing a higher thermal stability of these latter. These findings could be useful for understanding the dynamics-function relation in the mycomembrane and then to relate it to the low permeability and high resistance of mycobacteria to many antibiotics.

  6. A neutron scattering study on the stability of trehalose mycolates under thermal stress

    International Nuclear Information System (INIS)

    Migliardo, F.; Salmeron, C.; Bayan, N.

    2013-01-01

    Highlights: ► Neutron scattering measurements have been performed on mycolate water mixtures. ► A comparison with lecithin lipid water mixtures has been carried out. ► Mycolates show a lower mobility and flexibility compared to lecithin. ► The observed peculiarities of mycolic acids could be ascribed to trehalose. ► The results could justify the high resistance to thermal stress of mycobacteria. - Abstract: The present paper is focused on the study of the dynamics of mycolic acids, which are fundamental components of the outer membrane (mycomembrane) of Mycobacterium tuberculosis. An elastic neutron scattering study of mycolic acid/H 2 O and lecithin/H 2 O mixtures as a function of temperature and exchanged wavevector Q has been carried out. This study provides an effective way for characterizing the dynamical properties, furnishing a set of parameters characterizing the different flexibility and rigidity of the investigated lipids. The behavior of the elastically scattered intensity profiles and the derived mean square displacements as a function of temperature shows a more marked temperature dependence for lecithin lipids in comparison with mycolic acids, so revealing a higher thermal stability of these latter. These findings could be useful for understanding the dynamics-function relation in the mycomembrane and then to relate it to the low permeability and high resistance of mycobacteria to many antibiotics

  7. A study of phonon anisotropic scattering effect on silicon thermal conductivity at nanoscale

    Energy Technology Data Exchange (ETDEWEB)

    Bong, Victor N-S; Wong, Basil T. [Swinburne Sarawak Research Centre for Sustainable Technologies, Faculty of Engineering, Computing & Science, Swinburne University of Technology Sarawak Campus, 93350 Kuching, Sarawak (Malaysia)

    2015-08-28

    Previous studies have shown that anisotropy in phonon transport exist because of the difference in phonon dispersion relation due to different lattice direction, as observed by a difference in in-plane and cross-plane thermal conductivity. The directional preference (such as forward or backward scattering) in phonon propagation however, remains a relatively unexplored frontier. Our current work adopts a simple scattering probability in radiative transfer, which is called Henyey and Greenstein probability density function, and incorporates it into the phonon Monte Carlo simulation to investigate the effect of directional scattering in phonon transport. In this work, the effect of applying the anisotropy scattering is discussed, as well as its impact on the simulated thermal conductivity of silicon thin films. While the forward and backward scattering will increase and decrease thermal conductivity respectively, the extent of the effect is non-linear such that forward scattering has a more obvious effect than backward scattering.

  8. A study of phonon anisotropic scattering effect on silicon thermal conductivity at nanoscale

    International Nuclear Information System (INIS)

    Bong, Victor N-S; Wong, Basil T.

    2015-01-01

    Previous studies have shown that anisotropy in phonon transport exist because of the difference in phonon dispersion relation due to different lattice direction, as observed by a difference in in-plane and cross-plane thermal conductivity. The directional preference (such as forward or backward scattering) in phonon propagation however, remains a relatively unexplored frontier. Our current work adopts a simple scattering probability in radiative transfer, which is called Henyey and Greenstein probability density function, and incorporates it into the phonon Monte Carlo simulation to investigate the effect of directional scattering in phonon transport. In this work, the effect of applying the anisotropy scattering is discussed, as well as its impact on the simulated thermal conductivity of silicon thin films. While the forward and backward scattering will increase and decrease thermal conductivity respectively, the extent of the effect is non-linear such that forward scattering has a more obvious effect than backward scattering

  9. Computational study of the Rayleigh light scattering properties of atmospheric pre-nucleation clusters

    DEFF Research Database (Denmark)

    Elm, Jonas; Norman, Patrick; Bilde, Merete

    2014-01-01

    The Rayleigh and hyper Rayleigh scattering properties of the binary (H 2SO4)(H2O)n and ternary (H 2SO4)(NH3)(H2O)n clusters are investigated using a quantum mechanical response theory approach. The molecular Rayleigh scattering intensities are expressed using the dipole polarizability α...... and hyperpolarizability β tensors. Using density functional theory, we elucidate the effect of cluster morphology on the scattering properties using a combinatorial sampling approach. We find that the Rayleigh scattering intensity depends quadratically on the number of water molecules in the cluster and that a single...... ammonia molecule is able to induce a high anisotropy, which further increases the scattering intensity. The hyper Rayleigh scattering activities are found to be extremely low. This study presents the first attempt to map the scattering of atmospheric molecular clusters using a bottom-up approach...

  10. Experimental study of angular dependence in double photon Compton scattering

    International Nuclear Information System (INIS)

    Sandhu, B.S.; Dewan, R.; Saddi, M.B.; Singh, B.; Ghumman, B.S.

    2000-01-01

    The collision differential cross-section and energy of one of the final photons for double photon Compton scattering have been measured as a function of scattering angle θ 1 . The incident photon energy is 0.662 MeV and thin aluminium foils are used as a scatterer. The two simultaneously emitted photons in this higher order process are detected in coincidence using two NaI(Tl) scintillation spectrometers and 30 ns timing electronics. The measured values for energy and collision differential cross-section agree with theory within experimental estimated error. The present data provide information of angular dependence in this higher order process

  11. Ab initio simulations and neutron scattering studies of structure and dynamics in PdH

    International Nuclear Information System (INIS)

    Totolici, I.E.

    2001-07-01

    The work presented in this PhD thesis is concerned with the interpretation of the neutron scattering measurements from the palladium hydrogen system by means of ab initio electronic structure calculations. The motivation of performing such calculations was due to recent neutron scattering studies on this system that showed a strong directional dependence to the dynamical structure factor together with a complex dependence on energy. Here we attempt to describe the origin of these features by ab initio simulations of the dynamical structure factor. The method assumes an adiabatic separation of the motion of the proton and palladium atoms. The proton wave functions are calculated by a direct solution of the associated single-particle Schroedinger equation using a plane wave basis set method and a mapping of the adiabatic surface. The Fourier components of the adiabatic potential are obtained from LDA pseudopotential calculations. Using Fermi's golden rule within the Born approximation we were then able to calculate the dynamical structure factor, S(Q,ω), for exciting the proton from its ground state to various excited states as a function of the magnitude and direction of the scattering wave vector. The results are in agreement with the inelastic neutron scattering spectra and allow us to identify the origin of previous inexplicable features, in particular the strong directional dependence to the experimental data. The method was extended to investigate the expansion of the equilibrium lattice constant as a function of the H isotope when the zero-point energy of the proton/deuterium is explicitly taken into account in the relaxation process. The results we obtained predicted a bigger lattice constant for the hydride, as expected. Furthermore, other complex ab initio calculations were carried out in order to describe the origin of the large optic dispersion, seen previously in the coherent neutron scattering data. Our calculated dispersion proved to be in good

  12. Small-angle neutron scattering studies of sodium butyl benzene

    Indian Academy of Sciences (India)

    Na-NBBS), in aqueous solutions is investigated by small-angle neutron scattering (SANS). Nearly ellipsoidal aggregates of Na-NBBS at concentrations well above its minimum hydrotrope concentration were detected by SANS. The hydrotrope ...

  13. Life at extreme conditions: Neutron scattering studies of biological

    Indian Academy of Sciences (India)

    Extremophile bacteria; molecular adaptation; halophile; water dynamics; protein dynamics. ... Results of neutron scattering measurements on the dynamics of proteins ... The experiments were performed on a halophilic protein, and membrane ...

  14. Microscopic dynamics of the hydrogen bonded systems studied by quasi-elastic slow neutron scattering

    International Nuclear Information System (INIS)

    Padureanu, I.; Aranghel, D.; Radulescu, A.; Ion, M.; Lechner, R. E.; Desmedt, A.; Pieper, J.

    2002-01-01

    provide a satisfactory description of supercooled liquid dynamics. In order to contribute to an answer, we performed a new experiment of incoherent slow neutron scattering. Part of the obtained results is presented in a previously paper. Neutron scattering experiments were done at the time of flight spectrometer NEAT of the Berlin Neutron Scattering Center(BENSC). In this study we have used cold neutrons with the wavelength of λ = 5.1 A, which corresponds to an incident energy E o = 3.145 meV and a resolution ΔE = 98 μeV (full width at half-maximum, FWHM, of the elastic line of the vanadium sample). The scattering spectra were taken with 140 detectors in a large angular range 15.41 angle -1 for the elastic wave and the energy transfer hω s (θ,ω). The final data are obtained at 27 scattering angles as a function of the energy transfer hω for 8 temperatures 50 K, 100 K, 150 K, 188 K, 240 K, 290 K, 320 K and 400 K. The data have been also analyzed in terms of the generalized frequency distribution g (ω), the angular distribution dσ/dΩ of the quasi-elastically scattered neutrons and the observed line width ΔE = f (Q 0 2 , T). An obvious feature attribute to as boson peak is present at all temperatures from 50 K to 290 K in the dynamic scattering function Ss (θ,ω) and the generalized frequency distribution g (ω)/ω 2 of glycerol. The temperature dependence of the peak position shows an anomalous behavior near T g . This effect proves a soft dynamics additionally to the acoustic modes. At the same time the temperature dependence of the FWHM of the quasielastic line leads to a possible two step process approach in glycerol. (authors)

  15. Magnetic nanoparticles studied by small angle X-ray scattering

    International Nuclear Information System (INIS)

    Oliveira, Cristiano Luis Pinto; Antonel, Soledad; Negri, Martin

    2011-01-01

    because they exhibit magnetic (ferromagnetic) and electrical properties in the same material. Then, the nickel nanoparticles could be used for the development of electroelastic materials. In this case, the electrical conductivity of the material can be strongly dependent on the applied magnetic field, for example the case of nickel metal nanoparticles dispersed in a polymer, resulting in an anisotropic material with combined piezomagnetic and piezoelectric properties. In order to investigate the structural characteristics of cobalt-iron oxides and nickel nanoparticles, powder samples of those magnetic materials were studied by Small-Angle X-Ray Scattering. As will be shown, from the analysis and modeling of the scattering data, structural information could be obtained, enabling a detailed description of the structural properties of the studied samples which could be directly correlated to the magnetic properties. (author)

  16. Magnetic nanoparticles studied by small angle X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Cristiano Luis Pinto [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica. Grupo de Fluidos Complexos; Antonel, Soledad; Negri, Martin [Universidad de Buenos Aires (UBA) (Argentina). Facultad de Ciencias Exactas y Naturales. Dept. de Quimica Inorganica, Analitica y Quimica Fisica

    2011-07-01

    nanoparticles are very interesting because they exhibit magnetic (ferromagnetic) and electrical properties in the same material. Then, the nickel nanoparticles could be used for the development of electroelastic materials. In this case, the electrical conductivity of the material can be strongly dependent on the applied magnetic field, for example the case of nickel metal nanoparticles dispersed in a polymer, resulting in an anisotropic material with combined piezomagnetic and piezoelectric properties. In order to investigate the structural characteristics of cobalt-iron oxides and nickel nanoparticles, powder samples of those magnetic materials were studied by Small-Angle X-Ray Scattering. As will be shown, from the analysis and modeling of the scattering data, structural information could be obtained, enabling a detailed description of the structural properties of the studied samples which could be directly correlated to the magnetic properties. (author)

  17. Aspects of molecular dynamic of cyclohexanol studied by scattering of slow neutrons

    International Nuclear Information System (INIS)

    Walder, Vilma Sidneia

    1978-01-01

    Molecular dynamics of cyclohexanol in three crystalline phases and in the liquid state was investigated by cold neutron scattering in the temperature interval 100 to 300 K. The measurements were performed using a Beryllium Filter Time-of-Flight Spectrometer. The neutron inelastic scattering spectra and the frequency spectra fitted by a sum of Gaussians show evidences for events around 36-44. 62-79, 120-148, 216-250 and 384-509 c m -1 interpreted respectively as hundred rotation of molecules, lattice vibrations, H bond stretching vibration, out-of-line and in-plane ring bending modes. Quasi-elastic broadening were analysed in terms of modules for molecular diffusion. The behaviour of the self-diffusion coefficient with temperature was studied and the activation energies for diffusion in the liquid and solid states were determined. (author)

  18. Study on interaction between palladium(ІІ)-Linezolid chelate with eosin by resonance Rayleigh scattering, second order of scattering and frequency doubling scattering methods using Taguchi orthogonal array design

    Science.gov (United States)

    Thakkar, Disha; Gevriya, Bhavesh; Mashru, R. C.

    2014-03-01

    Linezolid reacted with palladium to form 1:1 binary cationic chelate which further reacted with eosin dye to form 1:1 ternary ion association complex at pH 4 of Walpole's acetate buffer in the presence of methyl cellulose. As a result not only absorption spectra were changed but Resonance Rayleigh Scattering (RRS), Second-order Scattering (SOS) and Frequency Doubling Scattering (FDS) intensities were greatly enhanced. The analytical wavelengths of RRS, SOS and FDS (λex/λem) of ternary complex were located at 538 nm/538 nm, 240 nm/480 nm and 660 nm/330 nm, respectively. The linearity range for RRS, SOS and FDS methods were 0.01-0.5 μg mL-1, 0.1-2 μg mL-1 and 0.2-1.8 μg mL-1, respectively. The sensitivity order of three methods was as RRS > SOS > FDS. Accuracy of all methods were determined by recovery studies and showed recovery between 98% and 102%. Intraday and inter day precision were checked for all methods and %RSD was found to be less than 2 for all methods. The effects of foreign substances were tested on RRS method and it showed the method had good selectivity. For optimization of process parameter, Taguchi orthogonal array design L8(24) was used and ANOVA was adopted to determine the statistically significant control factors that affect the scattering intensities of methods. The reaction mechanism, composition of ternary ion association complex and reasons for scattering intensity enhancement was discussed in this work.

  19. Lithium ion behavior in lithium oxide by neutron scattering studies

    International Nuclear Information System (INIS)

    Ishii, Yoshinobu; Morii, Yukio; Katano, Susumu; Watanabe, Hitoshi; Funahashi, Satoru; Ohno, Hideo; Nicklow, R.M.

    1992-01-01

    Lithium ion behavior in lithium oxide, Li 2 O, was studied in the temperature range from 293 K to 1120 K by the High-Resolution Powder Diffractometer (HRPD) installed in the JRR-3M. The diffraction patterns were analyzed with the RIETAN program. At room temperature, the thermal parameters related to the mean square of the amplitude of vibration of the lithium and the oxygen ions were 6 x 10 -21 m 2 and 4 x 10 -21 m 2 , respectively. AT 1120 K the thermal parameter of the lithium ion was 34 x 10 -21 m 2 . On the other hand, the parameter of the oxygen ion was 16 x 10 -21 m 2 . Inelastic neutron scattering studies for the lithium oxide single crystal were also carried out on the triple-axis neutron spectrometers installed at the JRR-2 and the HFIR. Although the value of a phonon energy of a transverse acoustic mode (Σ 3 ) at zone boundary was 30.6 meV at room temperature, this value was decreased to 25.1 meV at 700 K. This large softening was caused by anharmonicity of the crystal potential of lithium oxide. (author)

  20. A study of low Q2 radiative Bhabha scattering

    International Nuclear Information System (INIS)

    Karlen, D.A.

    1988-03-01

    This thesis presents a study of electron-positron scattering, via nearly real photon exchange, where in the process one or more high energy photons are produced. The motivations behind the work are twofold. Firstly, the study is a sensitive test of the theory of electron-photon interactions, quantum electrodynamics. A deviation from the theory could indicate that the electron is a composite particle. Secondly, a thorough understanding of this process is necessary for experiments to be done in the near future at the Stanford Linear Collider and the LEP facility at CERN. Calculations for the process to third and fourth order in pertubation theory are described. Methods for simulating the process by a Monte Carlo event generator are given. Results from the calculations are compared to data from the Mark II experiment at the PEP storage ring. The ratio of measured to calculated cross sections are 0.993 /+-/ 0.017 /+-/ 0.015 and 0.99 /+-/ 0.16 /+-/ 0.08 for final states with one and two observed photons respectively, where the first errors are statistical and the second systematic. The excellent agreement verifies the calculations of the fourth order radiative correction. No evidence for electron substructure is observed

  1. Intrabeam scattering studies at the Swiss light source

    CERN Document Server

    Antoniou, F; Aiba, M; Boege, M; Milas, N; Streun, A; Demma, T

    2012-01-01

    The target parameters of modern ultra-low emittance rings are entering into a regime where Intra-beam Scattering (IBS) becomes important and, in the case of linear collider damping rings, even a limitation for the delivered emittances. The Swiss Light Source (SLS) storage ring, as it has achieved a vertical geometrical emittance of around 1 pm at 2.4 GeV [1], and it has the ability to run at even lower energies, and the availability of emittance monitoring diagnostics, is an ideal testbed for IBS studies. Simulations using the classical IBS theories and tracking codes are undertaken in order to explore the possibilities and limitations for IBS measurements at the SLS. In this respect, comparison between the theories and codes is first discussed. The dependence of the output emittances, taking into account the effect of IBS, with respect to energy, bunch charge and zero current vertical and longitudinal emittance is also studied, in order to define the regimes where the IBS effect can be significant. First mea...

  2. Light Scatter in Optical Materials: Advanced Haze Modeling

    Science.gov (United States)

    2017-03-31

    contrast sensitivity with glare. This study measured angular scatter in the test articles , and showed that the cumulative (total) scatter beyond...Sample under laser illumination for angular scatter measurements ................................4  Figure 3: Scatter measurement system at a small...scatter effects image quality , visual performance and user acceptance. The purpose of the present effort was to develop a computational model that

  3. Collision-induced light scattering in a thin xenon layer between graphite slabs - MD study.

    Science.gov (United States)

    Dawid, A; Górny, K; Wojcieszyk, D; Dendzik, Z; Gburski, Z

    2014-08-14

    The collision-induced light scattering many-body correlation functions and their spectra in thin xenon layer located between two parallel graphite slabs have been investigated by molecular dynamics computer simulations. The results have been obtained at three different distances (densities) between graphite slabs. Our simulations show the increased intensity of the interaction-induced light scattering spectra at low frequencies for xenon atoms in confined space, in comparison to the bulk xenon sample. Moreover, we show substantial dependence of the interaction-induced light scattering correlation functions of xenon on the distances between graphite slabs. The dynamics of xenon atoms in a confined space was also investigated by calculating the mean square displacement functions and related diffusion coefficients. The structural property of confined xenon layer was studied by calculating the density profile, perpendicular to the graphite slabs. Building of a fluid phase of xenon in the innermost part of the slot was observed. The nonlinear dependence of xenon diffusion coefficient on the separation distance between graphite slabs has been found. Copyright © 2014. Published by Elsevier B.V.

  4. Diffuse neutron scattering study of Cu2−xSe

    DEFF Research Database (Denmark)

    Cava, R. J.; Andersen, Niels Hessel; Clausen, Kurt Nørgaard

    1986-01-01

    We have measured the diffuse neutron scattering in the hkk plane for Cu2Se and Cu1.8Se at 180°C and 51°C, respectively, in the cubic antifluorite type phase. The diffuse scattering shows significant structure, indicative of correlated short range mobile ion ordering. The short range order is foun...

  5. Experimental study on the location of energy windows for scatter correction by the TEW method in 201Tl imaging

    International Nuclear Information System (INIS)

    Kojima, Akihiro; Matsumoto, Masanori; Ohyama, Yoichi; Tomiguchi, Seiji; Kira, Mitsuko; Takahashi, Mutsumasa.

    1997-01-01

    To investigate validity of scatter correction by the TEW method in 201 Tl imaging, we performed an experimental study using the gamma camera with the capability to perform the TEW method and a plate source with a defect. Images were acquired with the triple energy window which is recommended by the gamma camera manufacturer. The result of the energy spectrum showed that backscattered photons were included within the lower sub-energy window and main energy window, and the spectral shapes in the upper half region of the photopeak (70 keV) were not changed greatly by the source shape and the thickness of scattering materials. The scatter fraction calculated using energy spectra and, visual observation and the contrast values measured at the defect using planar images also showed that substantial primary photons were included in the upper sub-energy window. In TEW method (for scatter correction), two sub-energy windows are expected to be defined on the part of energy region in which total counts mainly consist of scattered photons. Therefore, it is necessary to investigate the use of the upper sub-energy window on scatter correction by the TEW method in 201 Tl imaging. (author)

  6. Static and dynamic light scattering studies on dilute polyrotaxane solutions

    Science.gov (United States)

    Kume, Tetsuya; Araki, Jun; Sakai, Yasuhiro; Mayumi, Koichi; Kidowaki, Masatoshi; Yokoyama, Hideaki; Ito, Kohzo

    2009-08-01

    Static and dynamic light scattering measurements were performed for dilute polyrotaxane solutions in different types of solvent systems, i.e. dimethylacetamide (DMAc) or dimethylformamide (DMF) containing 1-6 wt% lithium chloride (LiCl), 1 M aqueous sodium hydroxide (NaOH) and dimethylsulfoxide (DMSO). No aggregation of the polyrotaxane in DMF/LiCl was confirmed in the present study. Radius of gyration of the dissolved polyrotaxane was largest in NaOHaq., followed by values in amide solvents/LiCl and that in DMSO, and was probably dominated not by Coulombic repulsion but by the mutual affinity between solvent and polyrotaxane. Ratio of radius of gyration to hydrodynamic radius suggested the flexible random-coiled conformation in DMSO and relatively more extended, semi-flexible ones in amide solvents/LiCl and NaOHaq. The obtained values of second virial coefficient and weight average molecular weight seemed to be affected by a potential change in differential refractive index increments, caused by selective macrocationization or ionization.

  7. Static and dynamic light scattering studies on dilute polyrotaxane solutions

    International Nuclear Information System (INIS)

    Kume, Tetsuya; Sakai, Yasuhiro; Mayumi, Koichi; Kidowaki, Masatoshi; Yokoyama, Hideaki; Ito, Kohzo; Araki, Jun

    2009-01-01

    Static and dynamic light scattering measurements were performed for dilute polyrotaxane solutions in different types of solvent systems, i.e. dimethylacetamide (DMAc) or dimethylformamide (DMF) containing 1-6 wt% lithium chloride (LiCl), 1 M aqueous sodium hydroxide (NaOH) and dimethylsulfoxide (DMSO). No aggregation of the polyrotaxane in DMF/LiCl was confirmed in the present study. Radius of gyration of the dissolved polyrotaxane was largest in NaOHaq., followed by values in amide solvents/LiCl and that in DMSO, and was probably dominated not by Coulombic repulsion but by the mutual affinity between solvent and polyrotaxane. Ratio of radius of gyration to hydrodynamic radius suggested the flexible random-coiled conformation in DMSO and relatively more extended, semi-flexible ones in amide solvents/LiCl and NaOHaq. The obtained values of second virial coefficient and weight average molecular weight seemed to be affected by a potential change in differential refractive index increments, caused by selective macrocationization or ionization.

  8. Breast cancer study in rats by using Raman scattering

    International Nuclear Information System (INIS)

    Martinez E, J. C.; Cordova F, T.; Roca Ch, J. M.; Hernandez R, A.

    2015-10-01

    Full text: The use of Raman scattering to differentiate the biochemistry and hence distinguish between normal and abnormal samples of breast cancer with induced stress was investigated. Twelve different rat serum samples (5 control samples and 7 breast cancer samples) were measured. 25 spectra per sample were acquired in a region of 50 X 50 microns. Three hundred spectra were recorded and the spectral diagnostic models were constructed by using multivariate statistical analysis on the spectral matrix to carry out the discrimination between the control samples and cancers samples with induced stress. The spectral recording was performed with Raman microscopy system Thermo Scientific XRD in the range from 200 to 2000 cm -1 with a laser source of 780 nm, 24 m W of power and 50 s and exposure time were used for each spectrum. It is shown that the serum samples from rats with breast cancer and the control group can be discriminate when the multivariate analysis methods are applied to their Raman data set. The ratios were significant and correspond to proteins and phospholipids. The preliminary results suggest that the Raman spectroscopy could be an alternative technique to study the breast cancer in humans in a near future. (Author)

  9. Studies of high energy lepton-nucleon scattering

    International Nuclear Information System (INIS)

    Ingelman, G.

    1982-05-01

    The first part of this thesis is related to the problem of detecting charmed particles. A new technique for observing very short decay paths in nuclear emulsions is developed and applied on a sample of neutrino induced reactions. Techniques for producing thick pellicles of nuclear track emulsion are also developed. In the second part, phenomenological investigations of deep inelastic lepton-nucleon scattering are made. Monte Carlo computer programs, based on the parton model and perturbative QCD for the initial hard process and the Lund model for the following soft hadronization, are used to simulate these reactions and thereby obtain explicit results. Generally good agreement is found when comparing these with experimental data, thus supporting this basic framework. Predictions to test QCD are made. Transverse momentum properties are studied in detail, in particular effects from soft gluon emission. The properties of a model for baryon production, both from the target remnant and the colour force field, are discussed and the results found to agree with data. It is shown that, at the presently available energies, the observable energy flow is not due to QCD, but arises from the baryon production in the target fragmentation. In a model to explain the observed Λ polarization, a connection between the confinement of quarks and these polarization phenomena is suggested. (Auth.)

  10. An improved scattering routine for collimation tracking studies at LHC

    CERN Document Server

    Tambasco, Claudia; Salvachua Ferrando, Maria Belen; Cavoto, Gianluca

    The present Master thesis work has been carried out at CERN in the framework of the LHC (Large Hadron Collider) Collimation project. The LHC accelerates proton beams up to 7 TeV colliding in the experiment detectors installed in four points of the accelerator ring. The LHC is built to store a energy of 360MJ for each beam. The energy deposition induced by local beam losses could quench the superconducting magnets located around the accelerator beam pipes. To prevent and keep under control dangerous beam losses, an efficient collimation system is required. In addition, the achievable LHC beam intensity is related to the beam loss rate and, consequently, to the cleaning efficiency of the collimation system. Collimation studies at LHC are carried out also by means of simulations by using SixTrack, a dedicated simulation tool that tracks a large numbers of particles for many turns around the ring. The SixTrack code includes a scattering routine to model proton interactions with the material of the collimators j...

  11. Lattice modes of hexamethylbenzene studied by inelastic neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Stride, J.A. [Institut Laue Langevin, 6 Rue Jules Horowitz, 38042 Grenoble (France)], E-mail: stride@ill.fr; Adams, J.M. [Institut Laue Langevin, 6 Rue Jules Horowitz, 38042 Grenoble (France); Johnson, M.R. [Institut Laue Langevin, 6 Rue Jules Horowitz, 38042 Grenoble (France)

    2005-10-31

    The combination of inelastic neutron scattering and detailed ab initio calculations has been used to arrive at accurate assignments of the low energy lattice mode region of hexamethylbenzene (HMB) across the low temperature first order phase transition at 117.5 K. This was also extended well into the mid-infrared spectral region and a good agreement was found between observed and calculated frequencies, which were also confirmed with isotopically substituted d-HMB. At low temperature, the lattice region is dominated by the methyl group torsions around 15 and 20 meV, which soften dramatically on passing into the higher temperature phase. The lowest energy methyl torsion corresponds to a coherent gear wheel motion, observed here for the first time and predicted in previous numerical studies of HMB. The three acoustic phonons lie to lower energy, centered around 6-7 meV, whilst the three optic phonons are very close in energy to the lowest methyl torsions. Other assignments are found to be in accord with literature values and so an unambiguous assignment of all spectral modes has been obtained for the first time. We conclude that due to the behaviour of the lattice modes either side of the phase transition, its nature is predominantly that of a thermally activated dynamic order-disorder transition.

  12. Lattice modes of hexamethylbenzene studied by inelastic neutron scattering

    International Nuclear Information System (INIS)

    Stride, J.A.; Adams, J.M.; Johnson, M.R.

    2005-01-01

    The combination of inelastic neutron scattering and detailed ab initio calculations has been used to arrive at accurate assignments of the low energy lattice mode region of hexamethylbenzene (HMB) across the low temperature first order phase transition at 117.5 K. This was also extended well into the mid-infrared spectral region and a good agreement was found between observed and calculated frequencies, which were also confirmed with isotopically substituted d-HMB. At low temperature, the lattice region is dominated by the methyl group torsions around 15 and 20 meV, which soften dramatically on passing into the higher temperature phase. The lowest energy methyl torsion corresponds to a coherent gear wheel motion, observed here for the first time and predicted in previous numerical studies of HMB. The three acoustic phonons lie to lower energy, centered around 6-7 meV, whilst the three optic phonons are very close in energy to the lowest methyl torsions. Other assignments are found to be in accord with literature values and so an unambiguous assignment of all spectral modes has been obtained for the first time. We conclude that due to the behaviour of the lattice modes either side of the phase transition, its nature is predominantly that of a thermally activated dynamic order-disorder transition

  13. Electronic structure of the palladium hydride studied by compton scattering

    CERN Document Server

    Mizusaki, S; Yamaguchi, M; Hiraoka, N; Itou, M; Sakurai, Y

    2003-01-01

    The hydrogen-induced changes in the electronic structure of Pd have been investigated by Compton scattering experiments associated with theoretical calculations. Compton profiles (CPs) of single crystal of Pd and beta phase hydride PdH sub x (x=0.62-0.74) have been measured along the [100], [110] and [111] directions with a momentum resolution of 0.14-0.17 atomic units using 115 keV x-rays. The theoretical Compton profiles have been calculated from the wavefunctions obtained utilizing the full potential linearized augmented plane wave method within the local density approximation for Pd and stoichiometric PdH. The experimental and the theoretical results agreed well with respect to the difference in the CPs between PdH sub x and Pd, and the anisotropy in the CPs of Pd or PdH sub x. This study provides lines of evidence that upon hydride formation the lowest valance band of Pd is largely modified due to hybridization with H 1s-orbitals and the Fermi energy is raised into the sp-band. (author)

  14. Breast cancer study in rats by using Raman scattering

    Energy Technology Data Exchange (ETDEWEB)

    Martinez E, J. C. [IPN, Unidad Profesional Interdisciplinaria de Ingenieria, Campus Guanajuato, Av. Mineral de Valenciana 200, Col. Fracc. Industrial Puerto Interior, 36275 Silao, Guanajuato (Mexico); Cordova F, T.; Roca Ch, J. M.; Hernandez R, A., E-mail: jcmartineze@ipn.mx [Universidad de Guanajuato, Division de Ciencias e Ingenierias, Departamento de Ingenieria Fisica, Loma del Bosque 103, Col. Lomas del Campestre, 37150 Leon, Guanajuato (Mexico)

    2015-10-15

    Full text: The use of Raman scattering to differentiate the biochemistry and hence distinguish between normal and abnormal samples of breast cancer with induced stress was investigated. Twelve different rat serum samples (5 control samples and 7 breast cancer samples) were measured. 25 spectra per sample were acquired in a region of 50 X 50 microns. Three hundred spectra were recorded and the spectral diagnostic models were constructed by using multivariate statistical analysis on the spectral matrix to carry out the discrimination between the control samples and cancers samples with induced stress. The spectral recording was performed with Raman microscopy system Thermo Scientific XRD in the range from 200 to 2000 cm{sup -1} with a laser source of 780 nm, 24 m W of power and 50 s and exposure time were used for each spectrum. It is shown that the serum samples from rats with breast cancer and the control group can be discriminate when the multivariate analysis methods are applied to their Raman data set. The ratios were significant and correspond to proteins and phospholipids. The preliminary results suggest that the Raman spectroscopy could be an alternative technique to study the breast cancer in humans in a near future. (Author)

  15. Recent results of studies of plasma fluctuations in stellarators by microwave scattering technique

    International Nuclear Information System (INIS)

    Skvortsova, N.N.; Batanov, G.M.; Kolik, L.V.; Petrov, A.E.; Pshenichnikov, A.A.; Sarksyan, K.A.; Kharchev, N.K.; Khol'nov, Yu.V.; Kubo, S.; Sanchez, J.

    2005-01-01

    -harmonic scattering. New results were obtained with the use of a small-angle scattering of the heating gyrotron radiation in LHD. In TJ-II, plasma density fluctuations were studied in experiments with the neutral beam injection. The experiments showed the presence of distinct quasi-harmonics in the first stage of the heating pulse. Simultaneously with these fluctuations, quasi-harmonics with the same frequencies were detected in the fluctuation signals of magnetic probes. Long time samples of density fluctuations (more than a million points at a sampling rate of 5 MHz) have for the first time measured. (author)

  16. Study of Cr52 and Ca40 nuclei by electron scattering

    International Nuclear Information System (INIS)

    Blum, Daniel

    1966-01-01

    As high energy electron scattering is a powerful mean to study nuclear structure, this research thesis first reports and comments results obtained while taking the Born approximation into account, and which are useful to interpret electron scattering experiments. The author describes how nucleus charge distribution parameters are obtained from these results of elastic scattering, and then addresses the case of inelastic scattering. Three nuclear models are presented. Then, after a brief presentation of the characteristics of the experimental installation, the author describes how raw results are processed to obtain cross sections, and discusses errors. The last parts address the study of chromium 52 and calcium 40 nuclei

  17. Studies of molecular dynamics with neutron scattering techniques. Part of a coordinated programme on neutron scattering techniques

    International Nuclear Information System (INIS)

    Vinhas, L.A.

    1980-05-01

    Molecular dynamics was studied in samples of tert-butanol, cyclohexanol and methanol, using neutron inelastic and quasi-elastic techniques. The frequency spectra of cyclohexanol in crystalline phase were interpreted by assigning individual energy peaks to hindered rotation of molecules, lattice vibration, hydrogen bond stretching and ring bending modes. Neutron quasi-elastic scattering measurements permitted the testing of models for molecular diffusion as a function of temperature. The interpretation of neutron incoherent inelastic scattering on methanol indicated the different modes of molecular dynamics in this material; individual inelastic peaks in the spectra could be assigned to vibrations of crystalline lattice, stretching of hydrogen bond and vibrational and torsional modes of CH 3 OH molecule. The results of the experimental work on tertbutanol indicate two distinct modes of motion in this material: individual molecular librations are superposed to a cooperative rotation diffusion which occurs both in solid and in liquid state

  18. Fast electron and X-ray scattering as a tool to study target's structure

    International Nuclear Information System (INIS)

    Amusia, M.Ya.

    2007-01-01

    We concentrate on several relatively new aspects of the study of fast electron and X-ray scattering by atoms and atom-like objects, namely endohedral atoms and fullerenes. However, main attention is given to fast charge particle scattering. We show that the corresponding cross-sections, being expressed via so-called generalized oscillator strengths (GOS), give information on the electronic structure of the target and on the role of electron correlations in it. We consider what sort of information became available when analyzing the dependence of GOS upon their multipolarity, transferred momentum q and energy ω. To obtain theoretical results, we employ both the one-electron Hartree-Fock approximation and account for the multi-electron correlation in the target, using the random phase approximation with exchange. We demonstrate the role of non-dipole corrections in the small-angle fast-electron inelastic scattering. There dipole contribution dominates while non-dipole corrections can be considerably and controllably enhanced as compared to the case of low and medium energy photoionization. We show also that analyses of GOS for discrete level excitations permit to clarify their multipolarity. The results of calculations of Compton excitation and ionization cross-sections are presented. Attention is given to cooperative effects in inelastic fast electron-atom scattering that results in directed motion of the secondary electrons, a phenomenon that is similar to 'drag currents' in photoionization. We demonstrate how one should derive GOS for endohedral atoms, e.g. A-C 60 and what is the additional information that can be obtained from corresponding GOS. Most of discussions are illustrated by the results of concrete calculations

  19. Contribution to the study of the transport-scattering equivalence

    International Nuclear Information System (INIS)

    Soldevila, Michel.

    1978-01-01

    The algorithm of the TERMINUS code that analytically resolves the equations of multigroup scattering in one dimensional plane geometry is described in this report. This code has been written and utilized to test the mathematical methods of transport-scattering equivalence. The results are then given of a comparison between the APOLLO, NEPTUNE and TERMINUS codes. The mathematical problem having been formulated, the reasons which led to the choice from among the alternative methods are explained thus enabling the ANACREON and KALGAN programmes to be written. The results achieved with these programs, both of which use TERMINUS as scattering code, are presented. The problems raised by coupling the ANACREON and KALGAN codes to the NEPTUNE system are mentioned and the results achieved with the equivalence module coupled to NEPTUNE are given [fr

  20. Study of pore growth in glassy carbon using small angle x-ray scattering

    International Nuclear Information System (INIS)

    Hoyt, J.

    1982-07-01

    Small-angle x-ray scattering was used to study the average pore size in glass-like carbon as a function of both heat-treatment time and heat-treatment temperature. A pore-growth model based on graphitization processes is presented. The simple mechanism shows that the change in the average radius of gyration with time is related to the total number of pores as a function of time, which in turn depends on the irreversible thermal-expansion phenomenon. The results of this study are inconsistent with a vacancy-migration pore-growth mechanism proposed earlier

  1. Spin waves in full-polarized state of Dzyaloshinskii-Moriya helimagnets: Small-angle neutron scattering study

    Science.gov (United States)

    Grigoriev, S. V.; Sukhanov, A. S.; Altynbaev, E. V.; Siegfried, S.-A.; Heinemann, A.; Kizhe, P.; Maleyev, S. V.

    2015-12-01

    We develop the technique to study the spin-wave dynamics of the full-polarized state of the Dzyaloshinskii-Moriya helimagnets by polarized small-angle neutron scattering. We have experimentally proven that the spin-waves dispersion in this state has the anisotropic form. We show that the neutron scattering image displays a circle with a certain radius which is centered at the momentum transfer corresponding to the helix wave vector in helimagnetic phase ks, which is oriented along the applied magnetic field H . The radius of this circle is directly related to the spin-wave stiffness of this system. This scattering depends on the neutron polarization showing the one-handed nature of the spin waves in Dzyaloshinskii-Moriya helimagnets in the full-polarized phase. We show that the spin-wave stiffness A for MnSi helimagnet decreased twice as the temperature increases from zero to the critical temperature Tc.

  2. Experimental study of Rayleigh scattering with a ruby laser beam: relative variation of scattered light with the number of scattering center and the gases nature

    International Nuclear Information System (INIS)

    Bayer, Charles

    1973-06-01

    The experimental variation of the scattered light with the number of scattering centers and with the refraction index of gases is in agreement with the theoretical Rayleigh scattering. A direct calibration System gives the absolute value of the Rayleigh ratio. The experimental value appears to be half of the theoretical one. (author) [fr

  3. Report of study meeting on nuclear physics of quasi-elastic scattering

    International Nuclear Information System (INIS)

    1992-10-01

    This meeting was held for three days from June 8 to 10, 1992, as one of the study meetings of Research Center for Nuclear Physics, Osaka University. The lectures were given on spin observables in quasi-elastic scattering, calculation of spin observables in 12 C, 40 Ca(p,n) reaction in quasifree scattering region, present state of quasi-elastic scattering, first results of (p,n) quasifree scattering with the new facility of the RCNP, spin-isospin response function and effect of Δ-hole configuration in finite nuclei, effective polarization of nuclei and observed amount of spin, (p,2p) measurement in the RCNP, quasi-elastic scattering in 2 H, 3 He and 4 He of polarized protons, quasifree Δ formation, 3 He(gamma, pπ ± ) reaction in Δ region, search for isobar components in 3 He by quasifree knockout studies, nonquasi-elastic process in photonuclear reaction, QF and NQF processes in gamma d→π + π - pn, coincidence scattering experiment in quasi-elastic scattering region, exclusive electron scattering of 3 He with full inclusion of final state interaction, quasi-elastic electron scattering and internucleon correlation and 13 other themes. (K.I.)

  4. Small-angle light scattering studies of dense AOT-water-decane microemulsions

    International Nuclear Information System (INIS)

    Micali, N.; Trusso, S.; Mallamace, F.; Chen, S.H.

    1996-01-01

    It is performed extensive studies of a three-component microemulsion system composed of AOT-water-decane using small-angle light scattering (SALS). The small-angle scattering intensities are measured in the angular interval 0.001-0.1 radians, corresponding to a Bragg wave number range of 0.14 μm -1 -1 . The measurements were made by changing temperature and volume fraction φ of the dispersed phase in the range 0.65< φ < 0.75. All samples have a fixed water-to-AOT molar ratio, w [water[/[AOT[ = 40.8, in order to keep the same average droplet size in the stable one-phase region. With the SALS technique it is observed all the phase boundaries of a very complex phase diagram with a percolation line and many structural organizations within it. It is observed at the percolation transition threshold, a scaling behavior of the intensity data. In addition it is described in detail a structural transition from a droplet microemulsion to a bi continuous one a suggested by a recent small-angle neutron scattering experiment. From the data analysis it is show that both the percolation phenomenon and this novel structural transition are described from a large-scale aggregation between microemulsion droplets

  5. Quasi-elastic neutron scattering studies of the slow dynamics of supercooled and glassy aspirin

    International Nuclear Information System (INIS)

    Zhang Yang; Mamontov, Eugene; Tyagi, Madhusudan; Chen, Sow-Hsin

    2012-01-01

    Aspirin, also known as acetylsalicylic acid (ASA), is not only a wonderful drug, but also a good glass former. Therefore, it serves as an important molecular system to study the near-arrest and arrested phenomena. In this paper, a high-resolution quasi-elastic neutron scattering (QENS) technique is used to investigate the slow dynamics of supercooled liquid and glassy aspirin from 410 down to 350 K. The measured QENS spectra can be analyzed with a stretched exponential model. We find that (i) the stretched exponent β(Q) is independent of the wavevector transfer Q in the measured Q range and (ii) the structural relaxation time τ(Q) follows a power-law dependence on Q. Consequently, the Q-independent structural relaxation time τ 0 can be extracted for each temperature to characterize the slow dynamics of aspirin. The temperature dependence of τ 0 can be fitted with the mode-coupling power law, the Vogel-Fulcher-Tammann equation and a universal equation for fragile glass forming liquids recently proposed by Tokuyama in the measured temperature range. The calculated dynamic response function χ T (Q, t) using the experimentally determined self-intermediate scattering function of the hydrogen atoms of aspirin shows direct evidence of the enhanced dynamic fluctuations as the aspirin is increasingly supercooled, in agreement with the fixed-time mean squared displacement (x 2 ) and the non-Gaussian parameter α 2 extracted from the elastic scattering.

  6. Quasi-Elastic Neutron Scattering Studies of the Slow Dynamics of Supercooled and Glassy Aspirin

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yang [ORNL; Tyagi, M. [NCNR and University of Maryland; Mamontov, Eugene [ORNL; Chen, Sow-hsin H [ORNL

    2011-01-01

    Aspirin, also known as acetylsalicylic acid (ASA), is not only a wonderful drug, but also a good glass former. Therefore, it serves as an important molecular system to study the near-arrest and arrested phenomena. In this paper, a high-resolution quasi-elastic neutron scattering (QENS) technique is used to investigate the slow dynamics of supercooled liquid and glassy aspirin from 410 K down to 350 K. The measured QENS spectra can be analyzed with a stretched exponential model. We find that (i) the stretched exponent (Q) is independent of the wave vector transfer Q in the measured Q-range, and (ii) the structural relaxation time (Q) follows a power law dependence on Q. Consequently, the Q-independent structural relaxation time 0 can be extracted for each temperature to characterize the slow dynamics of aspirin. The temperature dependence of 0 can be fitted with the mode coupling power law, the Vogel-Fulcher-Tammann equation and a universal equation for fragile glass forming liquids recently proposed by M. Tokuyama in the measured temperature range. The calculated dynamic response function T(Q,t) using the experimentally determined self-intermediate scattering function of the hydrogen atoms of aspirin shows a direct evidence of the enhanced dynamic fluctuations as the aspirin is increasingly supercooled, in agreement with the fixed-time mean squared displacement x2 and non-Gaussian parameter 2 extracted from the elastic scattering.

  7. Quasi-elastic neutron scattering studies of the slow dynamics of supercooled and glassy aspirin

    Science.gov (United States)

    Zhang, Yang; Tyagi, Madhusudan; Mamontov, Eugene; Chen, Sow-Hsin

    2012-02-01

    Aspirin, also known as acetylsalicylic acid (ASA), is not only a wonderful drug, but also a good glass former. Therefore, it serves as an important molecular system to study the near-arrest and arrested phenomena. In this paper, a high-resolution quasi-elastic neutron scattering (QENS) technique is used to investigate the slow dynamics of supercooled liquid and glassy aspirin from 410 down to 350 K. The measured QENS spectra can be analyzed with a stretched exponential model. We find that (i) the stretched exponent β(Q) is independent of the wavevector transfer Q in the measured Q range and (ii) the structural relaxation time τ(Q) follows a power-law dependence on Q. Consequently, the Q-independent structural relaxation time τ0 can be extracted for each temperature to characterize the slow dynamics of aspirin. The temperature dependence of τ0 can be fitted with the mode-coupling power law, the Vogel-Fulcher-Tammann equation and a universal equation for fragile glass forming liquids recently proposed by Tokuyama in the measured temperature range. The calculated dynamic response function χT(Q, t) using the experimentally determined self-intermediate scattering function of the hydrogen atoms of aspirin shows direct evidence of the enhanced dynamic fluctuations as the aspirin is increasingly supercooled, in agreement with the fixed-time mean squared displacement langx2rang and the non-Gaussian parameter α2 extracted from the elastic scattering.

  8. Kinetics of red blood cell rouleaux formation studied by light scattering.

    Science.gov (United States)

    Szolna-Chodór, Alicja; Bosek, Maciej; Grzegorzewski, Bronislaw

    2015-02-01

    Red blood cell (RBC) rouleaux formation was experimentally studied using a light scattering technique. The suspensions of RBCs were obtained from the blood of healthy donors. Hematocrit of the samples was adjusted ranging from 1% to 4%. Measurements of the intensity of the coherent component of light scattered by the suspensions were performed and the scattering coefficient of the suspensions was determined. The number of RBCs per rouleaux was obtained using anomalous diffraction theory. The technique was used to show the effect of time, hematocrit, and sample thickness on the process. The number of cells per rouleaux first increases linearly, reaches a critical value at ∼3 cells per rouleaux, and then a further increase in the rouleaux size is observed. The kinetic constant of the rouleaux growth in the linear region is found to be independent of hematocrit. The aggregation rate increases as the sample thickness increases. The time at which the critical region appears strongly decreases as the hematocrit of the suspension increases. © 2015 Society of Photo-Optical Instrumentation Engineers (SPIE)

  9. Small angle neutron scattering studies of mixed micelles of sodium

    Indian Academy of Sciences (India)

    The aqueous solutions of sodium cumene sulphonate (NaCS) and its mixtures with each of cetyl trimethylammonium bromide (CTAB) and sodium dodecyl sulphate (SDS) are characterized by small angle neutron scattering (SANS). NaCS when added to CTAB solution leads to the formation of long rod-shaped micelles with ...

  10. Time-dependent micro-Raman scattering studies of polyvinyl ...

    Indian Academy of Sciences (India)

    2014-02-15

    Feb 15, 2014 ... Micro-Raman scattering; surface plasmons; silver nanoparticles; polyvinyl alcohol. PACS Nos 74.25.nd; ... as well as their characterization. Added .... 3.2 Surface plasmon absorption of thin films of PVA + AgNO3. The surface ...

  11. Small-angle neutron scattering studies of nonionic surfactant: Effect

    Indian Academy of Sciences (India)

    Micellar solution of nonionic surfactant -dodecyloligo ethyleneoxide surfactant, decaoxyethylene monododecyl ether [CH3(CH2)11(OCH2CH2)10OH], C12E10 in D2O solution have been analysed by small-angle neutron scattering (SANS) at different temperatures (30, 45 and 60°C) both in the presence and absence of ...

  12. Dynamics of Magnetic Nanoparticles Studied by Neutron Scattering

    DEFF Research Database (Denmark)

    Hansen, Mikkel Fougt; Bødker, Franz; Mørup, Steen

    1997-01-01

    We present the first triple-axis neutron scattering measurements of magnetic fluctuations in nanoparticles using an antiferromagnetic reflection. Both the superparamagnetic relaxation and precession modes in similar to 15 nm hematite particles are: observed. The results have been consistently...... analyzed on the basis of a simple model with uniaxial anisotropy and the Neel-Brown theory for the relaxation....

  13. Spin dynamics in Tb studied by critical neutron scattering

    DEFF Research Database (Denmark)

    Dietrich, O. W.; Als-Nielsen, Jens Aage

    1971-01-01

    The inelasticity of the critical neutron scattering in Tb was measured at and above the Neel temperature. In the hydrodynamic region the line width Gamma (q=0, kappa 1)=C kappa z1, with z=1.4+or-0.1 and c=4.3+or-0.3 meVAAz. This result deviates from the conventional theory, which predicts...

  14. A study of Bhabha scattering at PETRA energies

    International Nuclear Information System (INIS)

    Braunschweig, W.; Gerhards, R.; Kirschfink, F.J.; Martyn, H.U.; Rosskamp, P.; Kolanoski, H.; Balkwill, C.; Bowler, M.G.; Burrows, P.N.; Cashmore, R.J.; Dauncey, P.; Heath, G.P.; Mellor, D.J.; Ratoff, P.; Tomalin, I.; Yelton, J.M.; Baranko, G.; Caldwell, A.; Izen, J.M.; Muller, D.; Ritz, S.; Strom, D.; Takashima, M.; Wicklund, E.; Wu Saulan; Zobernig, G.

    1988-01-01

    We report on high statistics Bhabha scattering data taken with the TASSO experiment at PETRA at center of mass energies from 12 GeV to 46.8 GeV. We present an analysis in terms of electroweak parameters of the standard model, give limits on QED cut-off parameters and look for possible signs of compositeness. (orig.)

  15. Pulsed Neutron Scattering Studies of Strongly Fluctuating solids, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Collin Broholm

    2006-06-22

    The conventional description of a solid is based on a static atomic structure with small amplitude so-called harmonic fluctuations about it. This is a final technical report for a project that has explored materials where fluctuations are sufficiently strong to severely challenge this approach and lead to unexpected and potentially useful materials properties. Fluctuations are enhanced when a large number of configurations share the same energy. We used pulsed spallation source neutron scattering to obtain detailed microscopic information about structure and fluctuations in such materials. The results enhance our understanding of strongly fluctuating solids and their potential for technical applications. Because new materials require new experimental techniques, the project has also developed new techniques for probing strongly fluctuating solids. Examples of material that were studied are ZrW2O8 with large amplitude molecular motion that leads to negative thermal expansion, NiGa2S4 where competing interactions lead to an anomalous short range ordered magnet, Pr1- xBixRu2O7 where a partially filled electron shell (Pr) in a weakly disordered environment produces anomalous metallic properties, and TbMnO3 where competing interactions lead to a magneto-electric phase. The experiments on TbMnO3 exemplify the relationship between research funded by this project and future applications. Magneto-electric materials may produce a magnetic field when an electric field is applied or vise versa. Our experiments have clarified the reason why electric and magnetic polarization is coupled in TbMnO3. While this knowledge does not render TbMnO3 useful for applications it will focus the search for a practical room temperature magneto-electric for applications.

  16. Use of scatter correction in quantitative I-123 MIBG scintigraphy for differentiating patients with Parkinsonism: Results from Phantom experiment and clinical study

    International Nuclear Information System (INIS)

    Bai, J.; Hashimoto, J.; Suzuki, T.; Nakahara, T.; Kubo, A.; Ohira, M.; Takao, M.; Ogawa, K.

    2007-01-01

    The aims of this study were to elucidate the feasibility of scatter correction in improving the quantitative accuracy of the Heart-to-Mediastinum (H/M) ratio in I-123 MIBG imaging and to clarify whether the H/M ratio calculated from the scatter corrected image improves the accuracy of differentiating patients with Parkinsonism from other neurological disorders. The H/M ratio was calculated using the counts from planar images processed with and without scatter correction in the phantom and on patients. The triple energy window (TEW) method was used for scatter correction. Fifty five patients were enrolled in the clinical study. The Receiver Operating Characteristic (ROC) Curve analysis was used to evaluate diagnostic performance. The H/M ratio was found to be increased after scatter correction in the phantom simulating normal cardiac uptake, while no changes were observed in the phantom simulating no uptake. It was observed that scatter correction stabilized the H/M ratio by eliminating the influence of scatter photons originating from the liver, especially in the condition of no cardiac uptake. Similarly, scatter correction increased the H/M ratio in conditions other than Parkinson's disease but did not show any change in Parkinson's disease itself to widen the differences in the H/M ratios between the two groups. The overall power of the test did not show any significant improvement after scatter correction in differentiating patients with Parkinsonism. Based on the results of this study it has been concluded that scatter correction improves the quantitative accuracy of H/M ratio in MIBG imaging, but it does not offer any significant incremental diagnostic value over conventional imaging (without scatter correction). Nevertheless it is felt that the scatter correction technique deserves special consideration in order to make the test more robust and obtain stable H/M ratios. (author)

  17. Study of macromolecules of biological interest by x-ray scattering

    International Nuclear Information System (INIS)

    Beltran, J.R.

    1987-08-01

    A brief review of the SAXS theory and experimental is presented. Solutions of crotamine, crotoxine, phospholipase and crotapotine are studied in several concentrations, extrapolated to infinite dilution and the results obtained are presented. The general shape of these proteins were also evaluated taking in consideration the relationships between the respective surface areas and volumes. A model was then devised taking into account the information available relative to aminoacid sequence, predicted secondary structure and spectroscopic data and its P(r) was calculated using the MULTIBODY program (Glatter (1980)). The P(r) curve is this way obtained showed a considerable agreement with the P(r) obtained resing the scattering curve. (author)

  18. Small-angle neutron-scattering studies of the magnetic phase diagram of MnSi

    DEFF Research Database (Denmark)

    Harris, P.; Lebech, B.; Hae Seop Shim

    1995-01-01

    The antiferromagnetic order of MnSi has been studied as function of temperature and applied magnetic field using small-angle neutron scattering. The results were analyzed using the three-dimensional resolution function and the scattering cross-section to model the diffraction data. Physical...

  19. Studying nanostructure gradients in injection-molded polypropylene/montmorillonite composites by microbeam small-angle x-ray scattering

    DEFF Research Database (Denmark)

    Stribeck, Norbert; Schneider, Konrad; Zeinolebadi, Ahmad

    2014-01-01

    The core–shell structure in oriented cylindrical rods of polypropylene (PP) and nanoclay composites (NCs) from PP and montmorillonite (MMT) is studied by microbeam small-angle x-ray scattering (SAXS). The structure of neat PP is almost homogeneous across the rod showing regular semicrystalline......-shaped phyllosilicate filler particles....

  20. Background studies for the MINER Coherent Neutrino Scattering reactor experiment

    International Nuclear Information System (INIS)

    Agnolet, G.; Baker, W.; Barker, D.; Beck, R.; Carroll, T.J.; Cesar, J.; Cushman, P.; Dent, J.B.; De Rijck, S.; Dutta, B.; Flanagan, W.; Fritts, M.; Gao, Y.; Harris, H.R.; Hays, C.C.; Iyer, V.

    2017-01-01

    The proposed Mitchell Institute Neutrino Experiment at Reactor (MINER) experiment at the Nuclear Science Center at Texas A&M University will search for coherent elastic neutrino-nucleus scattering within close proximity (about 2 m) of a 1 MW TRIGA nuclear reactor core using low threshold, cryogenic germanium and silicon detectors. Given the Standard Model cross section of the scattering process and the proposed experimental proximity to the reactor, as many as 5–20 events/kg/day are expected. We discuss the status of preliminary measurements to characterize the main backgrounds for the proposed experiment. Both in situ measurements at the experimental site and simulations using the MCNP and GEANT4 codes are described. A strategy for monitoring backgrounds during data taking is briefly discussed.

  1. Background studies for the MINER Coherent Neutrino Scattering reactor experiment

    Energy Technology Data Exchange (ETDEWEB)

    Agnolet, G.; Baker, W. [Department of Physics and Astronomy, and the Mitchell Institute for Fundamental Physics and Astronomy, Texas A& M University, College Station, TX 77843 (United States); Barker, D. [School of Physics & Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Beck, R. [Department of Physics and Astronomy, and the Mitchell Institute for Fundamental Physics and Astronomy, Texas A& M University, College Station, TX 77843 (United States); Carroll, T.J.; Cesar, J. [Department of Physics, University of Texas at Austin, Austin, TX 78712 (United States); Cushman, P. [School of Physics & Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Dent, J.B. [Department of Physics, University of Louisiana at Lafayette, Lafayette, LA 70504 (United States); De Rijck, S. [Department of Physics, University of Texas at Austin, Austin, TX 78712 (United States); Dutta, B. [Department of Physics and Astronomy, and the Mitchell Institute for Fundamental Physics and Astronomy, Texas A& M University, College Station, TX 77843 (United States); Flanagan, W. [Department of Physics, University of Texas at Austin, Austin, TX 78712 (United States); Fritts, M. [School of Physics & Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Gao, Y. [Department of Physics and Astronomy, and the Mitchell Institute for Fundamental Physics and Astronomy, Texas A& M University, College Station, TX 77843 (United States); Department of Physics & Astronomy, Wayne State University, Detroit 48201 (United States); Harris, H.R.; Hays, C.C. [Department of Physics and Astronomy, and the Mitchell Institute for Fundamental Physics and Astronomy, Texas A& M University, College Station, TX 77843 (United States); Iyer, V. [School of Physical Sciences, National Institute of Science Education and Research, Jatni - 752050 (India); and others

    2017-05-01

    The proposed Mitchell Institute Neutrino Experiment at Reactor (MINER) experiment at the Nuclear Science Center at Texas A&M University will search for coherent elastic neutrino-nucleus scattering within close proximity (about 2 m) of a 1 MW TRIGA nuclear reactor core using low threshold, cryogenic germanium and silicon detectors. Given the Standard Model cross section of the scattering process and the proposed experimental proximity to the reactor, as many as 5–20 events/kg/day are expected. We discuss the status of preliminary measurements to characterize the main backgrounds for the proposed experiment. Both in situ measurements at the experimental site and simulations using the MCNP and GEANT4 codes are described. A strategy for monitoring backgrounds during data taking is briefly discussed.

  2. Studies in deep inelastic scattering and vector meson photoproduction

    International Nuclear Information System (INIS)

    Busenitz, J.K.

    1985-01-01

    The first part of this thesis is devoted to a space-time analysis of deep inelastic scattering from protons at rest. Techniques are developed for identifying important space-time regions. These are then applied to obtain a space-time picture of deep inelastic scattering in the leading logarithmic approximation of QCD, Physical mechanisms responsible for the space-time picture are discussed. In the second part of this thesis he reports on the observations of elastic omega photoproduction from hydrogen by Fermilab Experiment-401. The omega was detected via its decay into the π + π - π 0 channel. Measurements of the energy, momentum transfer, and angular dependence of the cross section have been made for photon energies between 60 and 225 GeV

  3. Thermal neutron scattering studies of condensed matter under high pressures

    International Nuclear Information System (INIS)

    Carlile, C.J.; Salter, D.C.

    1978-01-01

    Although temperature has been used as a thermodynamic variable for samples in thermal neutron scattering experiments since the inception of the neutron technique, it is only in the last decade that high pressures have been utilised for this purpose. In the paper the problems particular to this field of work are outlined and a review is made of the types of high-pressure cells used and the scientific results obtained from the experiments. 103 references. (author)

  4. Neutron scattering studies of mixed-valence semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Mignot, J M [Laboratoire Leon Brillouin (LLB) - Centre d` Etudes de Saclay, 91 - Gif-sur-Yvette (France); Alekseev, P A [Kurchatov Institute, Moscow (Russian Federation)

    1994-12-31

    Neutron scattering experiments on the mixed-valence (MV) compounds SmB{sub 6} are reported. The inelastic magnetic response of SmB{sub 6} at T = 2 K, measured on a double-isotope single crystal,displays a strongly damped peak at 35 meV corresponding to the inter multiplet transition of Sm{sup 2+}. At lower energies ( h.{omega} {approx_equal} 14 meV), a narrow magnetic excitation is observed, with remarkable scattering-vector and temperature dependences of its intensity. This novel feature is discussed in terms of recent theoretical works describing the formation of an anisotropic local bound state in semiconducting MV materials. If the average samarium valence is decreased by substituting La for Sm, a peak is found to appear at high energies. The elastic magnetic form factor of SmB{sub 6} was determined using polarised neutrons and no significant difference is observed in its Q-dependence with respect to that of pure divalent samarium. This surprising behaviour is constant with previous measurements on the gold (high-pressure) phase of SmS. The above results are compared to those already reported for other MV materials. In particular existing information for TmSe is supplemented by recent inelastic scattering measurements carried out on a large stoichiometric single crystal. (author). 44 refs., 7 figs.

  5. Study on the influences of X Ray Scattering on radioscopic inspection

    Energy Technology Data Exchange (ETDEWEB)

    Wozniak, M.; Torrent, J.; Bancelin, A. [SNECMA NDE Dept. Laboratory, France, Evry Corbeil, 91 - Evry (France)

    2007-07-01

    This study issued from European project 'Verdict' (Virtual Evaluation and Robust Detection for engine Components non destructive Testing), aimed at developing and evaluating X Ray Non Destructive Method simulation. An qualitative appreciation and quantification for X Ray scattering for modelling (SINDBAD software) was identified. The effect of such radiation on radiogram results in a disturbing blur for interpretation of indications. The method and the results described are innovative in the analysis of X Ray scattering because for aeronautic field, the configurations used with this energy range are breakthrough. The approach followed consists in an experimental and practical method for evaluating scattered radiation on final image issued from the inspection. Experimental tests results confirmed that the influence of scattering radiation are linked to density variation, geometry of parts in the axis of direct radiation and spatial area. This study performed in industrial configurations contributed to improve X Ray scattering understanding. (authors)

  6. Nuclear resonance scattering study of iridates, iridium and antimony based pyrochlores

    International Nuclear Information System (INIS)

    Alexeev, P.

    2017-04-01

    This thesis shows the first synchrotron-based Moessbauer spectroscopy studies on iridium containing compounds and first vibrational spectroscopy on Sb containing compounds carried out at the P01 beamline of PETRA III. In this context, two types of X-ray monochromators have been developed: a monochromator for 73 keV photons with medium energy resolution, and a high-resolution backscattering monochromator based on a sapphire crystal. The monochromator for 73 keV X-rays is the key instrument for hyperfine spectroscopy on Iridium compounds, while the sapphire backscattering monochromator is purposed to vibrational spectroscopy on any Moessbauer resonances with the transition energies in the 20-50 keV range. Additionally, the signal detection for nuclear resonance scattering experiments at the beamline was significantly improved during this work, inspired by the high energies and low lifetimes of the employed resonances. The first synchrotron-based hyperfine spectroscopy on Iridium-containing compounds was demonstrated by NRS on 73 keV resonance in "1"9"3Ir. The results can be interpreted by dynamical theory of nuclear resonance scattering. In this work, special emphasis is set onto the electronic and magnetic properties of Ir nuclei in IrO_2 and in Ruddlesden-Popper (RP) phases of strontium iridates Sr_n_+_1Ir_nO_3_n_+_1 (n=0,1). These systems are well-suited for studies with X-ray scattering techniques, since the scattered signal contains vast information about the widely tunable crystallographic and electronic structure of these systems; furthermore, studies with X-rays are less limited by absorption from iridium as it is the case for neutron scattering experiments. The hyperfine parameters in IrO_2, SrIrO_3 and Sr_2IrO_4 have been measured via Nuclear Forward Scattering for the first time. Using the dynamical theory of NRS, the temperature and magnetic field dependence of the electric field gradient and magnetic hyperfine field on Ir nucleus have been determined for

  7. Nuclear resonance scattering study of iridates, iridium and antimony based pyrochlores

    Energy Technology Data Exchange (ETDEWEB)

    Alexeev, P.

    2017-04-15

    This thesis shows the first synchrotron-based Moessbauer spectroscopy studies on iridium containing compounds and first vibrational spectroscopy on Sb containing compounds carried out at the P01 beamline of PETRA III. In this context, two types of X-ray monochromators have been developed: a monochromator for 73 keV photons with medium energy resolution, and a high-resolution backscattering monochromator based on a sapphire crystal. The monochromator for 73 keV X-rays is the key instrument for hyperfine spectroscopy on Iridium compounds, while the sapphire backscattering monochromator is purposed to vibrational spectroscopy on any Moessbauer resonances with the transition energies in the 20-50 keV range. Additionally, the signal detection for nuclear resonance scattering experiments at the beamline was significantly improved during this work, inspired by the high energies and low lifetimes of the employed resonances. The first synchrotron-based hyperfine spectroscopy on Iridium-containing compounds was demonstrated by NRS on 73 keV resonance in {sup 193}Ir. The results can be interpreted by dynamical theory of nuclear resonance scattering. In this work, special emphasis is set onto the electronic and magnetic properties of Ir nuclei in IrO{sub 2} and in Ruddlesden-Popper (RP) phases of strontium iridates Sr{sub n+1}Ir{sub n}O{sub 3n+1} (n=0,1). These systems are well-suited for studies with X-ray scattering techniques, since the scattered signal contains vast information about the widely tunable crystallographic and electronic structure of these systems; furthermore, studies with X-rays are less limited by absorption from iridium as it is the case for neutron scattering experiments. The hyperfine parameters in IrO{sub 2}, SrIrO{sub 3} and Sr{sub 2}IrO{sub 4} have been measured via Nuclear Forward Scattering for the first time. Using the dynamical theory of NRS, the temperature and magnetic field dependence of the electric field gradient and magnetic hyperfine field

  8. Neutron scattering studies on magnetic excitations in complex ordered manganites

    Energy Technology Data Exchange (ETDEWEB)

    Senff, D

    2007-09-15

    This thesis deals with magnetic excitations in three different Manganese oxides, single-layered LaSrMnO{sub 4}, charge- and orbital-ordered La{sub 1/2}Sr{sub 3/2}MnO{sub 4}, and multiferroic TbMnO{sub 3}, which are studied by means of inelastic neutron scattering. The properties of the first system, LaSrMnO{sub 4}, are governed by the complex interplay of orbital, spin, and lattice degrees of freedom typical for the physics of manganites. The magnetic low-temperature behavior is quite unusual, and the comprehensive analysis of the spin-wave spectrum of LaSrMnO{sub 4} suggests a heterogenous ground state with ferromagnetic orbital polarons embedded in an antiferromagnetic background. The doped system La{sub 1/2}Sr{sub 3/2}MnO{sub 4} exhibits a stable charge- and orbital-ordered state, which today is discussed very controversially, as it is of great relevance for the colossal increase of electric conductivity at the metal-insulator transition in perovskite manganites. Analyzing the spin-wave dispersion of the ordered state, we find an excellent agreement with classical predictions by Goodenough and reject a recent alternative proposal. The different strength of the ferromagnetic and antiferromagnetic exchange in the CE-type ordering leads to the conclusion that the magnetic state has to be considered as a weak AFM coupling of stable FM elements. This thesis is further supported by the thermal evolution of the ordered state, revealing anisotropic correlations and the close competition of FM and AFM correlations above the Neel transition, as well as by the doping dependence of the charge- and orbital-ordered state, which is interpreted on the basis of a different response of the magnetic system with respect to additional electrons or holes. In the orthorhombic perovskite TbMnO{sub 3} the electric polarization is closely coupled to the magnetic degrees of freedom via a complex, non-collinear magnetic ordering. Precisely characterizing the different magnon excitations

  9. Neutron scattering studies on magnetic excitations in complex ordered manganites

    International Nuclear Information System (INIS)

    Senff, D.

    2007-09-01

    This thesis deals with magnetic excitations in three different Manganese oxides, single-layered LaSrMnO 4 , charge- and orbital-ordered La 1/2 Sr 3/2 MnO 4 , and multiferroic TbMnO 3 , which are studied by means of inelastic neutron scattering. The properties of the first system, LaSrMnO 4 , are governed by the complex interplay of orbital, spin, and lattice degrees of freedom typical for the physics of manganites. The magnetic low-temperature behavior is quite unusual, and the comprehensive analysis of the spin-wave spectrum of LaSrMnO 4 suggests a heterogenous ground state with ferromagnetic orbital polarons embedded in an antiferromagnetic background. The doped system La 1/2 Sr 3/2 MnO 4 exhibits a stable charge- and orbital-ordered state, which today is discussed very controversially, as it is of great relevance for the colossal increase of electric conductivity at the metal-insulator transition in perovskite manganites. Analyzing the spin-wave dispersion of the ordered state, we find an excellent agreement with classical predictions by Goodenough and reject a recent alternative proposal. The different strength of the ferromagnetic and antiferromagnetic exchange in the CE-type ordering leads to the conclusion that the magnetic state has to be considered as a weak AFM coupling of stable FM elements. This thesis is further supported by the thermal evolution of the ordered state, revealing anisotropic correlations and the close competition of FM and AFM correlations above the Neel transition, as well as by the doping dependence of the charge- and orbital-ordered state, which is interpreted on the basis of a different response of the magnetic system with respect to additional electrons or holes. In the orthorhombic perovskite TbMnO 3 the electric polarization is closely coupled to the magnetic degrees of freedom via a complex, non-collinear magnetic ordering. Precisely characterizing the different magnon excitations allows to identify all relevant modes of the

  10. Evaluation of penetration and scattering components in conventional pinhole SPECT: phantom studies using Monte Carlo simulation

    International Nuclear Information System (INIS)

    Deloar, Hossain M; Watabe, Hiroshi; Aoi, Toshiyuki; Iida, Hidehiro

    2003-01-01

    In quantitative pinhole SPECT, photon penetration through the collimator edges (penetration), and photon scattering by the object (object scatter) and collimator (collimator scatter) have not been investigated rigorously. Monte Carlo simulation was used to evaluate these three physical processes for different tungsten knife-edge pinhole collimators using uniform, hotspot and donut phantoms filled with 201 Tl, 99m Tc, 123 I and 131 I solutions. For the hotspot phantom, the penetration levels with respect to total counts for a 1 mm pinhole aperture were 78%, 28% and 23% for 131 I, 123 I and 99m Tc, respectively. For a 2 mm aperture, these values were 65% for 131 I, 16% for 123 I and 12% for 99m Tc. For all pinholes, 201 Tl penetration was less than 4%. The evaluated scatter (from object and collimator) with a hotspot phantom for the 1 mm pinhole was 24%, 16%, 18% and 13% for 201 Tl, 99m Tc, 123 I and 131 I, respectively. Summation of the object and collimator scatter for the uniform phantom was approximately 20% higher than that for the hotspot phantom. Significant counts due to penetration and object and collimator scatter in the reconstructed image were observed inside the core of the donut phantom. The collimator scatter can be neglected for all isotopes used in this study except for 131 I. Object scatter correction for all radionuclides used in this study is necessary and correction for the penetration contribution is necessary for all radionuclides but 201 Tl

  11. A study on the measurement of effective energy of scattering X-rays

    International Nuclear Information System (INIS)

    Oogama, Noboru; Fujimoto, Nobuhisa; Nishitani, Motohiro; Yamada, Katsuhiko

    1995-01-01

    Only a few studies have been reported on the measurement and evaluation of the effective energy of scattering X-rays using an ionization chamber. The reason for this is due to the difficulty in accurately measuring attenuation curve in scattering X-rays lacking any directional properties. We could come up with a new method for calculating the effective energy of scattering X-rays by utilizing their spectra data. First, for analysing the accuracy of our calculation method with using primary X-rays, a comparison was made of calculated values of the effective energy obtained by our calculation method with the measurement values obtained using an ionization chamber. The results gave the calculated values agreeing with the measurement values within a maximum error of 2%, and this method was very helpful in measuring the effective energy of the scattering X-rays. Consequently, this method was capable of measuring the effective energy of scattering X-rays in the following parameters: X-ray tube voltage, scattering angle and size of scatterer. In conclusion, it is considered that our method could solve the present difficulty regarding the measurement of effective energy of the scattering X-rays, and provided a useful procedure concerning the study of radiation protection. (author)

  12. Resonating-group study of p + α scattering from 68 to 125 MeV

    International Nuclear Information System (INIS)

    Thompson, D.R.; Brown, R.E.; LeMere, M.; Tang, Y.C.

    1977-01-01

    The resonating-group method, together with a phenomenological consideration of reaction effects, is used to analyze p + α scattering data at the relatively high c.m. energies of 68, 80, and 124.8 MeV. The nucleon-nucleon potential employed contains a weakly repulsive core and yields a reasonably satisfactory description of not only the two-nucleon scattering data but also the essential properties of the α particle. The result shows that satisfactory agreement with experiment can be obtained. In particular, it is found that, because of the use of a totally antisymmetric wave function, the scattering behavior at large angles is adequately described

  13. Further study of a new dispersion relation for electron-atom scattering

    International Nuclear Information System (INIS)

    Bhatia, A.K.; Temkin, A.

    1988-01-01

    A new recently proposed dispersion relation (DR) [Temkin, Bhatia, and Kim, J. Phys. B 19, L707 (1986)] is tested for e-He scattering; the results show that the new DR is not satisfied. Therefore we start to investigate the analytic structure of the difference amplitude, previously assumed to be nonsingular, on the negative scattering energy axis. Even under severe approximations we find that the difference amplitude contains both poles and branch points. This suggests, however, a useful approximation of these contributions to the DR which gives very satisfactory agreement in both e-H and e-He scattering. We conclude with some brief general remarks on this problem

  14. A study of light scattering of mononuclear blood cells with scanning flow cytometry

    International Nuclear Information System (INIS)

    Zharinov, Alexey; Tarasov, Peter; Shvalov, Alexander; Semyanov, Konstantin; Bockstaele, Dirk R. van; Maltsev, Valeri

    2006-01-01

    This study describes the measurement of light scattering of human mononuclear blood cells, the development of an appropriate optical model for those cells, and solution of the inverse light-scattering problem. The angular dependency of light-scattering intensity of mononuclear blood cells was experimentally measured by means of scanning flow cytometry. A sphere consisting of several concentric homogeneous layers with different refractive indices was tested as an optical model for mononuclear blood cells. A five-layer model has given the best agreement between experimental and theoretical light-scattering profiles. The inverse light-scattering problem was solved for a five-layer model with an optimization procedure that allows one to retrieve cell parameters: cell size relates to the outer diameter of the fifth layer; size of the nucleus relates to the outer diameter of the third layer. Mean values of cell size, nuclear size, refractive indices of nucleus and cellular cytoplasm were determined for blood monocytes and lymphocytes

  15. A sample cell to study hydrate formation with x-ray scattering

    International Nuclear Information System (INIS)

    Conrad, Heiko; Lehmkuehler, Felix; Sternemann, Christian; Feroughi, Omid; Tolan, Metin; Simonelli, Laura; Huotari, Simo

    2009-01-01

    We present a new sample cell for measuring nonresonant inelastic x-ray scattering spectra of a tetrahydrofuran (THF)-water liquid mixture and THF hydrate. The hydrate is formed inside the cell after nucleation seeds have been offered by a special magnetic stirring mechanism. Hydrate formation was verified by wide angle x-ray scattering and nonresonant x-ray Raman scattering spectra at the oxygen K-edge. A broad range of scattering angles can be studied with this cell which is necessary for momentum transfer dependent inelastic x-ray scattering. This cell is ideal to examine other liquid hydrate formers or other liquid samples, which have to be mixed in situ during the measurements.

  16. Study of scattering from turbulence structure generated by propeller with FLUENT

    Science.gov (United States)

    Luo, Gen

    2017-07-01

    In this article, the turbulence structure generated by a propeller is simulated with the computational fluid dynamics (CFD) software FLUENT. With the method of moments, the backscattering radar cross sections (RCS) of the turbulence structure are calculated. The scattering results can reflect the turbulent intensity of the wave profiles. For the wake turbulence with low rotating speed, the scattering intensity of HH polarization is much smaller than VV polarization at large incident angles. When the turbulence becomes stronger with high rotating speed, the scattering intensity of HH polarization also becomes stronger at large incident angles, which is almost the same with VV polarization. And also, the bistatic scattering of the turbulence structure has the similar situation. These scattering results indicate that the turbulence structure can also give rise to an anomaly compared with traditional sea surface. The study of electromagnetic (EM) scattering from turbulence structure generated by the propeller can help in better understanding of the scattering from different kinds of waves and provide more bases to explain the anomalies of EM scattering from sea surfaces.

  17. Contributions to atomic microdynamics study in some liquid metals by means of soft neutrons scattering

    International Nuclear Information System (INIS)

    Rotarescu, G.

    1981-01-01

    Measurements of inelastic scattering of soft neutrons on Bi and liquid Pb, applying all the necessary corrections in view of obtaining the dYnamic structure factor S(Q,ω) were performed. The F(Q,t) function of intermediate scattering was obtained by means of the Fourier transformation of S(Q,ω). Special attention was devoted to one multiple scattering correction, especially at small scattering angles, taking into account its influence on the results. A comparison of the experimental results with three recent theoretical models has shown a good agreement in the range of intermediate and high Q values. Measurements of neutron inelastic scattering on liquid sodium at a temperature of 233 Cdeg within a momentum transfer range of 1 A -1 -1 were performed. The scattering law S(α,β) that was compared to a series of theoretical models has been determined from the experimental data. The validity of the theoretical models for different ranges of energy and momenta was thoroughly checked. S(α,β) was calculated for each type of scattering since sodium proves a mixed, coherent and incoherent scattering agent. A study on the influence of the even interaction potential upon the S(Q,ω) dynamic structure factor, the fourth order momentum ω 4 (Q) and uoon the spectral function C(Q,ω) of longitudinal current correlations was performed. For this purpose, four potentials with oscillations at great distances and a Lennard-Jones type potential were used. (author)

  18. X-ray scattering studies of non-equilibrium ordering processes: Progress report, November 1, 1988--October 31, 1989

    International Nuclear Information System (INIS)

    Nagler, S.E.

    1989-01-01

    We report on the progress of our project entitled ''X-ray Scattering Studies of Non-Equilibrium Ordering Processes.'' In-house time-resolved x-ray scattering has been used to investigate ordering kinetics in single crystal thin films of Cu 3 Au. Scaling analysis of the results shows that two dimensional kinetic behavior is observed in 260 /angstrom/ thick films. Significant improvements have been made in the local capabilities for fast time resolved measurements and data analysis. Measurements of microphase separation and ordering kinetics have been made in block-co-polymers, and experiments on Au-Cd martensitic material are continuing. 15 refs., 7 figs

  19. Brillouin light scattering study of spin waves in NiFe/Co exchange spring bilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Haldar, Arabinda; Banerjee, Chandrima; Laha, Pinaki; Barman, Anjan, E-mail: abarman@bose.res.in [Thematic Unit of Excellence on Nanodevice Technology, Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Kolkata 700098 (India)

    2014-04-07

    Spin waves are investigated in Permalloy(Ni{sub 80}Fe{sub 20})/Cobalt(Co) exchange spring bilayer thin films using Brillouin light scattering (BLS) experiment. The magnetic hysteresis loops measured by magneto-optical Kerr effect show a monotonic decrease in coercivity of the bilayer films with increasing Py thickness. BLS study shows two distinct modes, which are modelled as Damon-Eshbach and perpendicular standing wave modes. Linewidths of the frequency peaks are found to increase significantly with decreasing Py layer thickness. Interfacial roughness causes to fluctuate exchange coupling at the nanoscale regimes and the effect is stronger for thinner Py films. A quantitative analysis of the magnon linewidths shows the presence of strong local exchange coupling field which is much larger compared to macroscopic exchange field.

  20. Light-scattering study of the glass transition in lubricants

    Science.gov (United States)

    Alsaad, M. A.; Winer, W. O.; Medina, F. D.; Oshea, D. C.

    1977-01-01

    The sound velocity of four lubricants has been measured as a function of temperature and pressure using Brillouin scattering. A change in slope of the velocity as a function of temperature or pressure allowed the determination of the glass transition temperature and pressure. The glass transition data were used to construct a phase diagram for each lubricant. The data indicate that the glass transition temperature increased with pressure at a rate which ranged from 120 to 200 C/GPa. The maximum pressure attained was 0.69 GPa and the temperature range was from 25 to 100 C.

  1. Neutron scattering studies of eco-friendly functional materials

    International Nuclear Information System (INIS)

    Mishra, S.K.; Gupta, M.K.; Mittal, R.; Krishna, P.S.R.; Chaplot, S.L.

    2016-01-01

    Niobate based materials are environment friendly and appropriate for wide piezoelectric applications due to their piezo-response that is comparable to Pb(Zr Ti)O_3 beyond the technological application, NaNbO_3 has been a rich model system for understanding of mechanisms of structural phase transitions when subject to changes in thermodynamical conditions like: temperature, pressure, and/or composition, particle size and external stimuli like electric/magnetic field etc. In the present work, we report systematic investigation of structural phase transitions with variations in temperature, external pressure and chemical pressure (via compositional modification) using the neutron scattering technique. (author)

  2. Computation of bessel functions in light scattering studies.

    Science.gov (United States)

    Ross, W D

    1972-09-01

    Computations of light scattering require finding Bessel functions of a series of orders. These are found most easily by recurrence, but excessive rounding errors may accumulate. Satisfactory procedures for cylinder and sphere functions are described. If argument z is real, find Y(n)(z) by recurrence to high orders. From two high orders of Y(n)(z) estimate J(n)(z). Use backward recurrence to maximum J(n)(z). Correct by forward recurrence to maximum. If z is complex, estimate high orders of J(n)(z) without Y(n)(z) and use backward recurrence.

  3. Theoretical study of the electron-cluster elastic scattering

    International Nuclear Information System (INIS)

    Descourt, P.; Guet, C.; Farine, M.

    1997-01-01

    The properties of the clusters consisting of some tens to several hundreds of alkali atoms are generally quite well described in the jellium approximation. This approximation treats the cluster as a charged Fermi liquid of finite size. The optical response predicted by this approximation and taking into account the electron-electron correlations of the Hartree-Fock mean field agrees rather well with the experiment. The objective of this work was to obtain a quantal many-body formalism, within jellium approximation, applicable to elastic scattering of electrons from an alkali-metal-cluster. Influence of correlations on the phase shifts was also taken into account

  4. Electron back scattered diffraction study of SmCo magnets

    International Nuclear Information System (INIS)

    Yonamine, T.; Fukuhara, M.; Machado, R.; Missell, F.P.

    2008-01-01

    The remanence and energy product of permanent magnets is a strong function of their crystallographic texture. Electron back scattered diffraction (EBSD) is a tool for texture analysis providing information about the atomic layers up to 50 nm below the surface of the material. This paper discusses experimental requirements for performing EBSD measurements on rare-earth permanent magnets and presents results on commercial SmCo magnet material. EBSD measurements proved to be very sensitive to misaligned grains and were sensitive to texture in good agreement with information provided by X-ray diffraction scans. Results for nanostructured Sm(CoFeCuZr) z magnets are also discussed

  5. Neutron and x-ray scattering studies of premartensitic phenomena

    International Nuclear Information System (INIS)

    Shapiro, S.M.

    1987-01-01

    This paper discusses neutron and x-ray investigations of some metallic alloys which are known to exhibit martensitic transformations. It is shown that precursor effects are usually present in the diffuse scattering and in the phonon dispersion curves, but the transition cannot be described in terms of the soft mode picture used in the Landau and Devonshire theory to describe structural phase transitions. In addition, it is noted that it is inappropriate to look at these microstructures as incommensurate systems, but more correctly as a coherent coexistence of two phases

  6. Initial study of deep inelastic scattering with ZEUS at HERA

    Science.gov (United States)

    Derrick, M.; Krakauer, D.; Magill, S.; Musgrave, B.; Repond, J.; Repond, S.; Stanek, R.; Talaga, R. L.; Thron, J.; Arzarello, F.; Ayad, R.; Barbagli, G.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Bruni, P.; Cara Romeo, G.; Castellini, G.; Chiarini, M.; Cifarelli, L.; Cindolo, F.; Ciralli, F.; Contin, A.; D'Auria, S.; del Papa, C.; Frasconi, F.; Giusti, P.; Iacobucci, G.; Laurenti, G.; Levi, G.; Lin, Q.; Lisowski, B.; Maccarrone, G.; Margotti, A.; Massam, T.; Nania, R.; Nemoz, C.; Palmonari, F.; Sartorelli, G.; Timellini, R.; Zamora Garcia, Y.; Zichichi, A.; Bargende, A.; Crittenden, J.; Dabbous, H.; Desch, K.; Diekmann, B.; Doeker, T.; Geerts, M.; Geitz, G.; Gutjahr, B.; Hartmann, H.; Hartmann, J.; Haun, D.; Heinloth, K.; Hilger, E.; Jakob, H.-P.; Kramarczyk, S.; Kückes, M.; Mass, A.; Mengel, S.; Mollen, J.; Monaldi, D.; Müsch, H.; Paul, E.; Schattevoy, R.; Schneider, J.-L.; Wedemeyer, R.; Cassidy, A.; Cussans, D. G.; Dyce, N.; Fawcett, H. F.; Foster, B.; Gilmore, R.; Heath, G. P.; Lancaster, M.; Llewellyn, T. J.; Malos, J.; Morgado, C. J. S.; Tapper, R. J.; Wilson, S. S.; Rau, R. R.; Barillari, T.; Schioppa, M.; Susinno, G.; Bernstein, A.; Caldwell, A.; Gialas, I.; Parsons, J. A.; Ritz, S.; Sciulli, F.; Straub, P. B.; Wai, L.; Yang, S.; Burkot, W.; Eskreys, A.; Piotrzkowski, K.; Zachara, M.; Zawiejski, L.; Borzemski, P.; Jeleń, K.; Kisielewska, D.; Kowalski, T.; Rulikowska-Zerȩbska, E.; Suszycki, L.; Zajc, J.; Kȩdzierski, T.; Kotański, A.; Przybycień, M.; Bauerdick, L. A. T.; Behrens, U.; Bienlein, J. K.; Coldewey, C.; Dannemann, A.; Dierks, K.; Dorth, W.; Drews, G.; Erhard, P.; Flasiński, M.; Fleck, I.; Fürtjes, A.; Gläser, R.; Göttlicher, P.; Hass, T.; Hagge, L.; Hain, W.; Hasell, D.; Hultschig, H.; Jahnen, G.; Joos, P.; Kasemann, M.; Klanner, R.; Koch, W.; Kötz, U.; Kowalski, H.; Labs, J.; Ladage, A.; Löhr, B.; Lüke, D.; Mainusch, J.; Manczak, O.; Momayezi, M.; Ng, J. S. T.; Nicel, S.; Notz, D.; Park, I. H.; Pösnecker, K.-U.; Rohde, M.; Ros, E.; Schneekloth, S.; Schroeder, J.; Schulz, W.; Selonke, F.; Stiliaris, E.; Tscheslog, E.; Tsurugai, T.; Turkot, F.; Vogel, W.; Woeniger, T.; Wolf, G.; Youngman, C.; Grabosch, H. J.; Leich, A.; Meyer, A.; Rethfeldt, C.; Schlensthdt, S.; Casalbuoni, R.; de Curtis, S.; Dominici, D.; Francescato, A.; Nuti, M.; Pelfer, P.; Anzivino, G.; Casaccia, R.; de Pasquale, S.; Qian, S.; Votano, L.; Bamberger, A.; Freidhof, A.; Poser, T.; Söldner-Rembold, S.; Theisen, G.; Trefzger, T.; Brook, N. H.; Bussey, P. J.; Doyle, A. T.; Forbes, J. R.; Jamieson, V. A.; Raine, C.; Saxon, D. H.; Brückmann, H.; Gloth, G.; Holm, U.; Kammerdocher, H.; Krebs, B.; Neumann, T.; Wick, K.; Hofmann, A.; Kröger, W.; Krüger, J.; Lohrmann, E.; Milewski, J.; Nakahata, M.; Pavel, N.; Poelz, G.; Salomon, R.; Seidman, A.; Schott, W.; Wiik, B. H.; Zetsche, F.; Bacon, T. C.; Butterworth, I.; Markou, C.; McQuillan, D.; Miller, D. B.; Mobayyen, M. M.; Prinias, A.; Vorvolakos, A.; Bienz, T.; Kreutzmann, H.; Mallik, U.; McCliment, E.; Roco, M.; Wang, M. Z.; Cloth, P.; Filges, D.; Chen, L.; Imlay, R.; Kartik, S.; Kim, H.-J.; McNeil, R. R.; Metcalf, W.; Barreiro, F.; Cases, G.; Hervás, L.; Labarga, L.; del Peso, J.; Roldán, J.; Terrón, J.; de Trocóniz, J. F.; Ikraiam, F.; Mayer, J. K.; Smith, G. R.; Corriveau, F.; Gilkinson, D. J.; Hanna, D. S.; Hung, L. W.; Mitchell, J. W.; Patel, P. M.; Sinclair, L. E.; Stairs, D. G.; Ullmann, R.; Bashindzhagyan, G. L.; Ermolov, P. F.; Golubkov, Y. A.; Kuzmin, V. A.; Kuznetsov, E. N.; Savin, A. A.; Voronin, A. G.; Zotov, N. P.; Bentvelsen, S.; Dake, A.; Engelen, J.; de Jong, P.; de Jong, S.; de Kamps, M.; Kooijman, P.; Kruse, A.; van der Lugt, H.; O'dell, V.; Straver, J.; Tenner, A.; Tiecke, H.; Uijterwaal, H.; Vermeulen, J.; Wiggers, L.; de Wolf, E.; van Woudenberg, R.; Yoshida, R.; Bylsma, B.; Durkin, L. S.; Li, C.; Ling, T. Y.; McLean, K. W.; Murray, W. N.; Park, S. K.; Romanowski, T. A.; Seidlein, R.; Blair, G. A.; Butterworth, J. M.; Byrne, A.; Cashmore, R. J.; Cooper-Sarkar, A. M.; Devenish, R. C. E.; Gingrich, D. M.; Hallam-Baker, P. M.; Harnew, N.; Khatri, T.; Long, K. R.; Luffman, P.; McArthur, I.; Morawitz, P.; Nash, J.; Smith, S. J. P.; Roocroft, N. C.; Wilson, F. F.; Abbiendi, G.; Brugnera, R.; Carlin, R.; dal Corso, F.; de Giorgi, M.; Dosselli, U.; Gasparini, F.; Limentani, S.; Morandin, M.; Posocco, M.; Stanco, L.; Stroili, R.; Voci, C.; Field, G.; Lim, J. N.; Oh, B. Y.; Whitmore, J.; Contino, U.; D'Agostini, G.; Guida, M.; Iori, M.; Mari, S. M.; Marini, G.; Mattioli, M.; Nigro, A.; Hart, J. C.; McCubbin, N. A.; Shah, T. P.; Short, T. L.; Barberis, E.; Cartiglia, N.; Heusch, C.; Hubbard, B.; Leslie, J.; O'Shaughnessy, K.; Sadrozinski, H. F.; Seiden, A.; Badura, E.; Biltzinger, J.; Chaves, H.; Rost, M.; Seifert, R. J.; Walenta, A. H.; Weihs, W.; Zech, G.; Dagan, S.; Levy, A.; Zer-Zion, D.; Hasegawa, T.; Hazumi, M.; Ishii, T.; Kasai, S.; Kuze, M.; Nagasawa, Y.; Nakao, M.; Okuno, H.; Tokushuku, K.; Watanabe, T.; Yamada, S.; Chiba, M.; Hamatsu, R.; Hirose, T.; Kitamura, S.; Nagayama, S.; Nakamitsu, Y.; Arneodo, M.; Costa, M.; Ferrero, M. I.; Lamberti, L.; Maselli, S.; Peroni, C.; Solano, A.; Staiano, A.; Dardo, M.; Bailey, D. C.; Bandyopadhyay, D.; Benard, F.; Bhadra, S.; Brkic, M.; Burow, B. D.; Chlebana, F. S.; Crombie, M. B.; Hartner, G. F.; Levman, G. M.; Martin, J. F.; Orr, R. S.; Prentice, J. D.; Sampson, C. R.; Stairs, G. G.; Teuscher, R. J.; Yoon, T.-S.; Bullock, F. W.; Catterall, C. D.; Giddings, J. C.; Jones, T. W.; Khan, A. M.; Lane, J. B.; Makkar, P. L.; Shaw, D.; Shulman, J.; Blankenship, K.; Gibaut, D. B.; Kochocki, J.; Lu, B.; Mo, L. W.; Charchula, K.; Ciborowski, J.; Gajewski, J.; Grzelak, G.; Kasprzak, M.; Krzyżanowski, M.; Muchorowski, K.; Nowak, R. J.; Pawlak, J. M.; Stojda, K.; Stopczyński, A.; Szwed, R.; Tymieniecka, T.; Walczak, R.; Wróblewski, A. K.; Zakrzewski, J. A.; Zarnecki, A. F.; Adamus, M.; Abramowicz, H.; Eisenberg, Y.; Glasman, C.; Karshon, U.; Montag, A.; Revel, D.; Shapira, A.; Ali, I.; Behrens, B.; Camerini, U.; Dasu, S.; Fordham, C.; Foudas, C.; Goussiou, A.; Lomperski, M.; Loveless, R. J.; Nylander, P.; Ptacek, M.; Reeder, D. D.; Smith, W. H.; Silverstein, S.; Frisken, W. R.; Furutani, K. M.; Iga, Y.

    1993-04-01

    Results are presented on neutral current, deep inelastic scattering measured in collisions of 26.7 GeV electrons and 820 GeV protons. The events typically populate a range in Q2 from 10 to 100 GeV2. The values of x extend down to x ~ 10-4 which is two orders of magnitude lower than previously measured at such Q2 values in fixed target experiments. The measured cross sections are in accord with the extrapolations of current parametrisations of parton distributions.

  7. Design Study for Direction Variable Compton Scattering Gamma Ray

    Science.gov (United States)

    Kii, T.; Omer, M.; Negm, H.; Choi, Y. W.; Kinjo, R.; Yoshida, K.; Konstantin, T.; Kimura, N.; Ishida, K.; Imon, H.; Shibata, M.; Shimahashi, K.; Komai, T.; Okumura, K.; Zen, H.; Masuda, K.; Hori, T.; Ohgaki, H.

    2013-03-01

    A monochromatic gamma ray beam is attractive for isotope-specific material/medical imaging or non-destructive inspection. A laser Compton scattering (LCS) gamma ray source which is based on the backward Compton scattering of laser light on high-energy electrons can generate energy variable quasi-monochromatic gamma ray. Due to the principle of the LCS gamma ray, the direction of the gamma beam is limited to the direction of the high-energy electrons. Then the target object is placed on the beam axis, and is usually moved if spatial scanning is required. In this work, we proposed an electron beam transport system consisting of four bending magnets which can stick the collision point and control the electron beam direction, and a laser system consisting of a spheroidal mirror and a parabolic mirror which can also stick the collision point. Then the collision point can be placed on one focus of the spheroid. Thus gamma ray direction and collision angle between the electron beam and the laser beam can be easily controlled. As the results, travelling direction of the LCS gamma ray can be controlled under the limitation of the beam transport system, energy of the gamma ray can be controlled by controlling incident angle of the colliding beams, and energy spread can be controlled by changing the divergence of the laser beam.

  8. Dynamics of biopolymers on nanomaterials studied by quasielastic neutron scattering and MD simulations

    Science.gov (United States)

    Dhindsa, Gurpreet K.

    Neutron scattering has been proved to be a powerful tool to study the dynamics of biological systems under various conditions. This thesis intends to utilize neutron scattering techniques, combining with MD simulations, to develop fundamental understanding of several biologically interesting systems. Our systems include a drug delivery system containing Nanodiamonds with nucleic acid (RNA), and two specific model proteins, beta-Casein and Inorganic Pyrophosphatase (IPPase). RNA and nanodiamond (ND) both are suitable for drug-delivery applications in nano-biotechnology. The architecturally flexible RNA with catalytic functionality forms nanocomposites that can treat life-threatening diseases. The non-toxic ND has excellent mechanical and optical properties and functionalizable high surface area, and thus actively considered for biomedical applications. In this thesis, we utilized two tools, quasielastic neutron scattering (QENS) and Molecular Dynamics Simulations to probe the effect of ND on RNA dynamics. Our work provides fundamental understanding of how hydrated RNA motions are affected in the RNA-ND nanocomposites. From the experimental and Molecular Dynamics Simulation (MD), we found that hydrated RNA motion is faster on ND surface than a freestanding one. MD Simulation results showed that the failure of Stokes Einstein relation results the presence of dynamic heterogeneities in the biomacromolecules. Radial pair distribution function from MD Simulation confirmed that the hydrophilic nature of ND attracts more water than RNA results the de-confinement of RNA on ND. Therefore, RNA exhibits faster motion in the presence of ND than freestanding RNA. In the second project, we studied the dynamics of a natively disordered protein beta-Casein which lacks secondary structures. In this study, the temperature and hydration effects on the dynamics of beta-Casein are explored by Quasielastic Neutron Scattering (QENS). We investigated the mean square displacement (MSD) of

  9. Study of the elastic scattering differential cross sections of a proton beam by a cesium target

    International Nuclear Information System (INIS)

    El Maddarsi, Mohamed.

    1978-01-01

    The elastic differential cross section of H + on Cs is studied experimentally and theoretically. The experimental device is described, after which the differential cross-section values obtained as a function of the laboratory angle are given for four incident energies: 13.4 eV, 15.1 eV, 17.7 eV and 24.2 eV. By means of an interaction potential of the quasi-molecule H + Cs the differential cross sections are calculated for the same incident energies; this calculation uses the semi-classical method of stationary phases which shows clearly the limits of conventional description and the changes introduced by quantum effects. Very good agreement is obtained between theoretical and experimental results, which shows that elastic scattering is very little perturbed by inelastic channels in this energy range. The estimated inelastic cross section at 24 eV is about 1.9 10 -15 cm 2 , corresponding to 1.6% of the scattering process [fr

  10. Protein folding and protein metallocluster studies using synchrotron small angler X-ray scattering

    International Nuclear Information System (INIS)

    Eliezer, D.

    1994-06-01

    Proteins, biological macromolecules composed of amino-acid building blocks, possess unique three dimensional shapes or conformations which are intimately related to their biological function. All of the information necessary to determine this conformation is stored in a protein's amino acid sequence. The problem of understanding the process by which nature maps protein amino-acid sequences to three-dimensional conformations is known as the protein folding problem, and is one of the central unsolved problems in biophysics today. The possible applications of a solution are broad, ranging from the elucidation of thousands of protein structures to the rational modification and design of protein-based drugs. The scattering of X-rays by matter has long been useful as a tool for the characterization of physical properties of materials, including biological samples. The high photon flux available at synchrotron X-ray sources allows for the measurement of scattering cross-sections of dilute and/or disordered samples. Such measurements do not yield the detailed geometrical information available from crystalline samples, but do allow for lower resolution studies of dynamical processes not observable in the crystalline state. The main focus of the work described here has been the study of the protein folding process using time-resolved small-angle x-ray scattering measurements. The original intention was to observe the decrease in overall size which must accompany the folding of a protein from an extended conformation to its compact native state. Although this process proved too fast for the current time-resolution of the technique, upper bounds were set on the probable compaction times of several small proteins. In addition, an interesting and unexpected process was detected, in which the folding protein passes through an intermediate state which shows a tendency to associate. This state is proposed to be a kinetic molten globule folding intermediate

  11. Contribution to the study of the elastic scattering of the system 16O+12C

    International Nuclear Information System (INIS)

    Charles, Pierre.

    1981-03-01

    It is generally accepted, in the study of elastic scattering of the 16 O+ 12 C system, that each resonance corresponds to an inherent state of the angular momentum. It does not seem satisfactory to attribute an angular momentum to a resonance without having studied the variation in the angular matrix elements at a scattering resonance in terms of the energy. Now, when not one angular distribution, but a set of angular distributions is examined at adjacent energies, the conclusion is reached that a partial wave has no particular behaviour, but that the structures observed are due to a correlation between the different partial waves. The structures observed between 19 MeV and 24 MeV in the centre of mass system (35 to 40 MeV in 28 Si) do not correspond to inherent states of the angular momentum. Then, one must either assume that the total momentum is not a constant of the movement or that the structures observed correspond to groupings of different levels of angular momentum. The phase shift analysis clearly suggests the existence of groupings of levels reflecting the presence of intermediate structures at 36 MeV and 39 MeV in 28 Si. At such an excitation energy, the mean lives of these structures are assumed to be very short and hence the width of the different levels is great with regard to their spacing: this does not make it possible to show up the 'fine structure' of the resonances because, (a) all the resonant partial waves interfere with each other and (b) the continuous coupling introduces a fluctuating part in the scattering amplitude. The exchange process of two 12 C cores is certainly not unimportant and it has been noticed that certain behaviours of the angular distributions are well reproduced when a term depending on the parity is added to the optical potential [fr

  12. Light scattering studies of lower dimensional colloidal particle and critical fluid systems

    International Nuclear Information System (INIS)

    O'Sullivan, W.J.; Mockler, R.C.

    1984-09-01

    The authors have studied the response to compression of colloidal particle crystals in monolayers on the surface of water. The crystals deform elastically as the crystals are compressed in a Langmuir trough from a lattice spacing of ten microns to spacings less than two microns. A phase transition to a close packed triangular lattice phase occurs at very high densities, when the attractive van der Waals/steric interations between particles dominate. The authors have found that the aggregates formed, when a colloidal particle monolayer coagulates following switching off of the repulsive electric dipole-dipole interactions, show scale invariance with a fractal dimension consistent with the prediction of a theory of diffusion limited aggregation in two dimensions. The authors have made progress toward the development of a computer processed array detector-spectrometer to be used in studies of melting and crystallization of two dimensional colloidal particle films. Stable black bilipid membranes have been produced, both spherical and planar, with and without embedded microparticles. We have modified our heterodyne autocorrelation spectrometer, used for studies of the dynamic response of critical fluid films, to enable us to measure the intensity autocorrelation of light scattered at forward angles. Rayleigh linewidth data has been gathered from a 1.9 micron film of a 2,6-lutidine+water critical mixture, taken at a scattering angle of ten degrees. The preliminary results indicate that the film dynamical response remains that of an equivalent three dimensional system, in apparent disgreement with recent theoretical predictions of Calvo and Ferrell

  13. Gun Shows and Gun Violence: Fatally Flawed Study Yields Misleading Results

    Science.gov (United States)

    Hemenway, David; Webster, Daniel; Pierce, Glenn; Braga, Anthony A.

    2010-01-01

    A widely publicized but unpublished study of the relationship between gun shows and gun violence is being cited in debates about the regulation of gun shows and gun commerce. We believe the study is fatally flawed. A working paper entitled “The Effect of Gun Shows on Gun-Related Deaths: Evidence from California and Texas” outlined this study, which found no association between gun shows and gun-related deaths. We believe the study reflects a limited understanding of gun shows and gun markets and is not statistically powered to detect even an implausibly large effect of gun shows on gun violence. In addition, the research contains serious ascertainment and classification errors, produces results that are sensitive to minor specification changes in key variables and in some cases have no face validity, and is contradicted by 1 of its own authors’ prior research. The study should not be used as evidence in formulating gun policy. PMID:20724672

  14. Neutron scattering and diffraction instrument for structural study on biology in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Niimura, Nobuo [Japan Atomic Energy Research Inst., Ibaraki-ken (Japan)

    1994-12-31

    Neutron scattering and diffraction instruments in Japan which can be used for structural studies in biology are briefly introduced. Main specifications and general layouts of the instruments are shown.

  15. Annual report on neutron scattering studies in JAERI, September 1, 1978 - August 31, 1979

    International Nuclear Information System (INIS)

    Iizumi, Masashi; Endoh, Yasuo

    1980-03-01

    Neutron scattering studies carried out from September 1978 to August 1979 by Division of Physics, JAERI, and universities with JRR-2 and -3 neutron beam facilities are described: 51 summary reports, and a list of publications. (author)

  16. Scattering of neutrons by catalase: a study of molecules, subunits, and tubules

    International Nuclear Information System (INIS)

    Randall, J.; Starling, D.; Baldwin, J.P.; Ibel, K.

    1976-01-01

    The paper deals with small-angle scattering of neutrons by catalase tetramers, dimers, and monomers and with neutron diffraction by helical assemblies of tetramers in the form of tubules. A preliminary study of catalase is described

  17. A Monte Carlo study of the acceptance to scattered events in a depth encoding PET camera

    International Nuclear Information System (INIS)

    Moisan, C.; Tupper, P.; Rogers, J.G.; DeJong, J.K.

    1995-10-01

    We present a Monte Carlo study of acceptance to scattered events in a Depth Encoding Large Aperture Camera (DELAC), a hypothetical PET scanner with the capacity to encode the depth-of-interaction (DOI) of incident γ-rays. The simulation is initially validated against the measured energy resolution and scatter fraction of the ECAT-953B scanner. It is then used to assess the response to scattered events in a PET camera made of position encoding blocks of the EXACT HR PLUS type, modified to have DOI resolution through a variation in the photopeak pulse height. The detection efficiency for 511 keV γ-rays, as well as for those that scattered in the object or left only part of their energy in the block, is studied for several combinations of DOI sensitivities and block thicknesses. The scatter fraction predicted by the simulation for DELACs of various ring radii is compared to that of the ECAT-953B as a function of the energy threshold. The results indicate that the poorer discrimination of object scatters with depth sensitive blocks does not lead to a dramatic increase of the scatter fraction. (author). 10 refs., 1 tab., 5 figs

  18. Magnetism reflectometer study shows LiF layers improve efficiency in spin valve devices

    Energy Technology Data Exchange (ETDEWEB)

    Bardoel, Agatha A [ORNL; Lauter, Valeria [ORNL; Szulczewski, Greg J [ORNL

    2012-01-01

    -emitting diodes, has been found to enhance the injection of electrons through the semiconductor. Researchers from the University of Alabama and ORNL used polarized neutrons at the magnetism reflectometer at SNS to investigate the electronic, magnetic, and structural properties of the electrodes in a novel system. In this system, the magnetic layers cobalt and Ni{sub 80}Fe{sub 20} are interfaced with spacer layers composed of the organic semiconductor Alq3. A coupling layer of LiF is inserted to separate the magnetized layers from the semiconductor. 'ALQ3 is an organic semiconductor material,' said Lauter. 'Normally in these systems a first magnetic layer is grown on a hard substrate so that one can get the controlled magnetic parameters. Then you grow the organic semiconductor layer, followed by another magnetic material layer, such as cobalt.' In addition to determining the effect of the LiF layers on the efficiency of the electron injection, the researchers wanted to determine the magnetic properties of the cobalt and Ni{sub 80}Fe{sub 20} as well as the interfacial properties: whether there is interdiffusion of cobalt through the LiF layer to the semiconductor, for example. The researchers used polarized neutrons at beam line 4A to probe the entire, layer-by-layer assembly of the system. 'Reflectometry with polarized neutrons is a perfect method to study thin magnetic films,' Lauter said. 'These thin films - if you put one on a substrate, you see it just like a mirror. However, this mirror has a very complicated internal multilayer structure. The neutrons look inside this complicated structure and characterize each and every interface. Due to the depth sensitivity of the method, we measure the structural and magnetic properties of each layer with the resolution of 0.5 nm. The neutron scattering results found that inserting LiF as a barrier significantly improves the quality of the interface, increasing the injection of electrons from the

  19. Raman scattering and attenuated-total-reflection studies of surface-plasmon polaritons

    International Nuclear Information System (INIS)

    Kurosawa, K.; Pierce, R.M.; Ushioda, S.; Hemminger, J.C.

    1986-01-01

    We have made in situ measurements of attenuated total reflection (ATR) and Raman scattering from a layered structure consisting of a glass prism, a thin silver film, an MgF 2 spacer, and a liquid mixture whose refractive index is matched to that of MgF 2 . When the incident angle of the laser beam coincides with the ATR angle, the surface-plasmon polariton (SPP) of the silver film is excited resonantly and the Raman scattering intensity of the liquid shows a maximum. The same effect is observed at the frequency of the Stokes scattered light. By measuring the decrease of the Raman scattering intensity of the liquid with increase of the thickness of the MgF 2 spacer layer, we have determined the decay length (l/sub d/) of the SPP field into the liquid. The measured value of l/sub d/ = 1539 A agrees with the calculated value, 1534 A

  20. A small angle neutron scattering study of mica based glass-ceramics with applications in dentistry

    International Nuclear Information System (INIS)

    Kilcoyne, S.H.; Bentley, P.M.; Al-Jawad, M.; Bubb, N.L.; Al-Shammary, H.A.O.; Wood, D.J.

    2004-01-01

    We are currently developing machinable and load-bearing mica-based glass-ceramics for use in restorative dental surgery. In this paper we present the results of an ambient temperature small angle neutron scattering (SANS) study of several such ceramics with chemical compositions chosen to optimise machinability and strength. The SANS spectra are all dominated by scattering from the crystalline-amorphous phase interface and exhibit Q -4 dependence (Porod scattering) indicating that, on a 100 A scale, the surface of the crystals is smooth

  1. Feasibility study of direct spectra measurements for Thomson scattered signals for KSTAR fusion-grade plasmas

    Science.gov (United States)

    Park, K.-R.; Kim, K.-h.; Kwak, S.; Svensson, J.; Lee, J.; Ghim, Y.-c.

    2017-11-01

    Feasibility study of direct spectra measurements of Thomson scattered photons for fusion-grade plasmas is performed based on a forward model of the KSTAR Thomson scattering system. Expected spectra in the forward model are calculated based on Selden function including the relativistic polarization correction. Noise in the signal is modeled with photon noise and Gaussian electrical noise. Electron temperature and density are inferred using Bayesian probability theory. Based on bias error, full width at half maximum and entropy of posterior distributions, spectral measurements are found to be feasible. Comparisons between spectrometer-based and polychromator-based Thomson scattering systems are performed with varying quantum efficiency and electrical noise levels.

  2. Ribosome formation from subunits studied by stopped-flow and Rayleigh light scattering

    Directory of Open Access Journals (Sweden)

    Antoun Ayman

    2004-01-01

    Full Text Available Light scattering and standard stopped-flow techniques were used to monitor rapid association of ribosomal subunits during initiation of eubacterial protein synthesis. The effects of the initiation factors IF1, IF2, IF3 and buffer conditions on subunit association were studied along with the role of GTP in this process. The part of light scattering theory that is essential for kinetic measurements is high-lighted in the main text and a more general treatment of Rayleigh scattering from macromolecules is given in an appendix.

  3. Giant magnetic quadrupole resonance studied with 180 deg. electron scattering

    CERN Document Server

    Neumann-Cosel, P V

    1999-01-01

    The nuclei sup 4 sup 8 Ca and sup 9 sup 0 Zr were investigated in 180 deg. high-resolution inelastic electron scattering for momentum transfers q approx =0.35-0.8 fm sup - sup 1. Complete M2 strength distributions could be extracted in both nuclei up to excitation energies of about 15 MeV utilizing a fluctuation analysis technique. Second-RPA calculations successfully describe the experimentally observed strong fragmentation of the M2 mode. The quenching of the spin part is found to be comparable to the M1 case, contrary to previous claims suggesting a stronger reduction. A quantitative reproduction of the data requires the presence of appreciable orbital strength which can be interpreted as a torsional elastic vibration (the so-called twist mode).

  4. Nuclear spin response studies in inelastic polarized proton scattering

    International Nuclear Information System (INIS)

    Jones, K.W.

    1988-01-01

    Spin-flip probabilities S/sub nn/ have been measured for inelastic proton scattering at incident proton energies around 300 MeV from a number of nuclei. At low excitation energies S/sub nn/ is below the free value. For excitation energies above about 30 MeV for momentum transfers between about 0.35 fm/sup /minus/1/ and 0.65 fm/sup / minus/1/ S/sub nn/ exceeds free values significantly. These results suggest that the relative ΔS = 1(ΔS = 0 + ΔS = 1) nuclear spin response approaches about 90% in the region of the enhancement. Comparison of the data with slab response calculations are presented. Decomposition of the measured cross sections into σ(ΔS = 0) and σ(ΔS = 1) permit extraction of nonspin-flip and spin-flip dipole and quadrupole strengths. 29 refs., 11 figs

  5. Deeply Virtual Compton Scattering Studies at Jefferson Lab

    International Nuclear Information System (INIS)

    Sabatie, F.

    2010-11-01

    This document describes the early experimental effort at Jefferson Lab to unravel the Generalized Parton Distributions (GPD), using the Deeply Virtual Compton Scattering (DVCS) process. The GPDs contain the usual form factors and parton distribution functions, but in addition, they include correlations between states of different longitudinal and transverse momenta. They therefore give access to a three-dimensional picture of the nucleon. DVCS is the cleanest process allowing to extract GPDs, and as early as 2000, a number of experiments were proposed for this purpose. The results of the first exploratory experiments are presented as well as the first measurements of linear combinations of GPDs. In addition, a thorough discussion on the insights gained from these early experiments is proposed, linked with the theoretical tools used to extract GPDs from DVCS data. Finally, improvements on what was done for this first experimental phase are proposed and discussed, and new proposals and measurements are described. (author)

  6. A small angle neutron scattering study of thermoplastic elastomer

    Energy Technology Data Exchange (ETDEWEB)

    Sutiarso,; Edy Giri, R Putra; Andon, Insani; Sudirman,; Sudaryanto, [Materials Science Research Centre, National Atomic Energy Agency, Jakarta (Indonesia)

    1998-10-01

    A bilateral scientific cooperation, in the small angle neutron scattering has been agreed upon between CIAE, China and BATAN, Indonesia as well as MINT Malaysia. As stated in the agreed proposal that the objective of this cooperation, in the initial stage (stage-1), was to have a regional intercomparison measurements of SANS instruments in order to determine their characteristic/performance. Therefore, this report is supposed to describe the progress in the SANS instrument development of each country involved during the period of 1996/97 and some activities related to the SANS instrument. Since, up to now, we have not yet received any progresses reported from either China or Malaysia, this report will describe the progress of SANS`s activities in BATAN only. (author)

  7. Anomalous x-ray scattering studies of functional disordered materials

    International Nuclear Information System (INIS)

    Kohara, S; Tajiri, H; Song, C H; Ohara, K; Temleitner, L; Sugimito, K; Fujiwara, A; Pusztai, L; Usuki, T; Hosokawa, S; Benino, Y; Kitamura, N; Fukumi, K

    2014-01-01

    We have developed anomalous x-ray scattering (AXS) spectrometers, that employ intrinsic Ge detectors and crystal analyzers, at SPring-8. The use of LiF analyzer crystal provides us with an energy resolution of ∼ 12 eV. Furthermore, it has been established that the use of AXS technique is essential to reveal the relationship between the atomic structure and its function of a fast phase-change material, Ge 2 Sb 2 Te 5 . We were able to address the issue of why the amorphous phase of fast phase change materials is stable at room temperature for a long time despite the fact that it can rapidly transform to the crystalline phase by using a combination of AXS and large scale density functional theory-based molecular dynamics simulations.

  8. Study on Scattering Theory and Perturbative Quantum Chromodynamics: case of quark-antiquark Top pair production

    International Nuclear Information System (INIS)

    Randriamisy, H.D.E.

    2014-01-01

    Nowadays, the study of scattering and production of particles occupies an important place in subatomic physics research. The main ongoing experiments concern high-energy scattering in the colliders, the scattering theory based on quantum field theory is used for the theoretical study. The work presented in this thesis is located in this framework, in fact it concerns a study on the scattering theory and Perturbative Quantum Chromodynamics. We used the path integral formalism of quantum field theory and perturbation theory. As we considered the higher order corrections in perturbative developments, the renormalization theory with the method of dimensional regularization was also used. As an application, the case of the Top quark production was considered. As main results, we can quote the obtention of the cross section of quark-antiquark top pair production up to second order. [fr

  9. Neutron scattering studies of the phase-transitions of ices by thermal-annealing

    International Nuclear Information System (INIS)

    Wang, Y.; Kolesnikov, A.; Li, J.C.

    1999-01-01

    Complete text of publication follows. Inelastic incoherent neutron scattering was used to study the phase-transition process of high-density amorphous (hda) ice produced by pressurising ice-Ih at 16 kbar and 77 K to low-density amorphous (Ida) ice, ice-Ic and ice-Ih by thermobaric treatments. The results show that when annealing temperature is lower than 136 K no obvious phase-transition was observed and transformation of the hda to the lda ice occurs between 136 and 144 K which is very closed to the theoretically calculated value 135 K (1). Comparing the lda spectrum with the vapour deposited low-density amorphous ice (2) shows a number of differences in the translational and vibrational regions, such as the low energy cut off of the vibrational band. On the other hand, the recovered lda from the hda ice has a similar spectrum as ice-Ih. (author)

  10. Vesicle formation in the block copolymer/ homopolymer mixture studied by scattering methods

    International Nuclear Information System (INIS)

    Koizumi, Satoshi; Hasegawa, Hirokazu; Hashimoto, Takeji; Suzuki, Junnich.

    1993-01-01

    We studied morphology and spatial segmental distribution of particular binary mixtures of poly(styrene-block-isoprene)(SI) and homopolystyren, either protonated (HS) or deuterated (DS), with small angle-X-ray scattering (SAXS) and neutron scattering (SANS). The block copolymer SI used itself had a lamellar microdomain. Molecular weights of HS and DS were identical to each other and equal also to that of polystyrene block (PS) in SI. SAXS results obtained for SI and HS mixtures show that: (1) HS is solubilized in the PS microdomains; (2) the polyisoprene lamella has the thickness independent of w HS , weight fraction of HS, but its undulation depends on w HS . These two findings, in turn, imply that the HS added is localized in the middle of the PS microdomains, i.e., in between the PS brushes emanating from the interface of SI. We further confirmed this implication by SANS with a deuterium labeling technique; the DS segments studied for the SI/DS mixture is localized in the middle of PS microdomain with the penetration depth of 10 nm between DS and PS block chains. (author)

  11. Pitch angle scattering and particle precipitation in a pulsating aurora - an experimental study

    International Nuclear Information System (INIS)

    Sandahl, I.

    1984-10-01

    A pulsating aurora occurring during the recovery phase of a substorm on January 27, 1979 was monitored by a large set of instruments. The Swedish sounding rocket S23-L2 was launched at magnetic midnight over pulsating patches, some of which exhibited 3+-1 Hz modulation. The ground based instrumentation included auroral TV cameras, all sky cameras, photometers and magnetometers. The geostationary satellite GEOS-2 was located in the equatorial plane, approximately conjugate to the rocket. The central experiment of this study is the particle experiment on the rocket. Several aspects of pulsating auroras have been investigated. The auroral luminosity variations were very well correlated to variations in the flux of precipitating hot electrons. The 1-20 second pulsations were caused by increased fluxes of 4-40 keV electrons. The 3+-1 Hz modulation was detected in 7-200 keV electrons, but the biggest energy flux modulation occurred for electrons of about 60 keV. Model calculations involving the electron distributions measured by the sounding rocket and GEOS-2, consistently show that the electrons may have been scattered into the loss cone through the Doppler shifted gyroresonance with whistler mode waves. The scattering was not a pure pitch angle scattering as in the classical Coroniti and Kennel theory, but involved also a systematic energy loss from the particles. The waves were probably hiss with some chorus elements. The equatorial plane plasma density was estimated in two independent ways to be about 2x10 6 m- 3 . The 3+-1 Hz modulation was measured both by the particle experiment on the rocket and by the wave experiment on GEOS-2. Properties of the modulated fluxes are described and a qualitative model for the cause of the modulation is proposed. (author)

  12. Dynamics of proteins and of their hydration layer studied by neutron scattering and additional biophysical methods

    International Nuclear Information System (INIS)

    Gallat, Francois-Xavier

    2011-01-01

    This thesis work focused on the dynamics of proteins, surrounded by their hydration layer, a water shell around the protein vital for its biological function. Each of these components is accompanied by a specific dynamics which union reforms the complex energy landscape of the system. The joint implementation of selective deuteration, incoherent neutron scattering and tera-hertz spectroscopy allowed to explore the dynamics of proteins and that of the hydration shell. The influence of the folding state of protein on its dynamics has been studied by elastic neutron scattering. Globular proteins were less dynamic than its intrinsically disordered analogues. Themselves appear to be stiffer than non-physiological unfolded proteins. The oligomerization state and the consequences on the dynamics were investigated. Aggregates of a globular protein proved to be more flexible than the soluble form. In contrast, aggregates of a disordered protein showed lower average dynamics compared to the soluble form. These observations demonstrate the wide range of dynamics among the proteome. Incoherent neutron scattering experiences on the hydration layer of globular and disordered proteins have yielded information on the nature of water motion around these proteins. The measurements revealed the presence of translational motions concomitant with the onset of the transition dynamics of hydration layers, at 220 K. Measurements have also shown a stronger coupling between a disordered protein and its hydration water, compared to a globular protein and its hydration shell. The nature of the hydration layer and its influence on its dynamics has been explored with the use of polymers that mimic the water behavior and that act as a source of flexibility for the protein. Eventually, the dynamics of methyl groups involved in the dynamical changes observed at 150 and 220 K, was investigated. (author) [fr

  13. Neutron scattering study of magnetic and crystalline electirc field interactions in RCrO3

    International Nuclear Information System (INIS)

    Shamir, N.

    1978-05-01

    Magnetic and crystalline electric field interactions in the compounds RCrO 3 (R-rare earth) , were studied by neutron scattering. Elastic neutron scattering was utilized in the study of the temperature dependence of the Cr 3+ and Ho 3+ magnetic reflections in Lu CrO 3 and HoCrO 3 , respectively. Analysis of this temperature dependence yielde constant canting angles for the Cr 3+ and Ho 3+ magnetic moments. Molecular magnetic field constants and crystalline electric field splitting were also calculated from the temperature dependence of the Ho 3+ magnetic reflection. These parameters were obtained directly by inelastic neutron scattering measurement. Inelastic neutron scattering measurements of crystlline electric field transitions of R 3+ (R=Pr, Nd, Tb, Ho, Er, Tm, Yb) in RCrO 3 , formed the basis for the calculation of the common crystalline electirc field parameters of the heavy R 3+ ions. (author)

  14. Theoretical study of parity violating asymmetry in proton-proton (pp) scattering

    International Nuclear Information System (INIS)

    Singh, S.K.; Sajjad Athar, M.; Waris, Atiya

    2000-01-01

    Measurements of parity violating asymmetries in the pp scattering and proton-nucleus scattering with polarised protons provide a very useful tool to study the interplay of weak and strong interactions between the nucleons and within the nucleus. In order to understand these processes in terms of the conventional nucleon-nucleon interaction models, new experiments at the intermediate energies of 221 and 450 MeV and in the higher energy of multi GeV range are to be carried out

  15. Study of hot carrier relaxation in quantum wells by subpicosecond Raman scattering

    International Nuclear Information System (INIS)

    Kim, Dai-sik; Yu, P.Y.

    1990-03-01

    Relaxation of hot carriers excited by subpicosecond laser pulses has been studied by Raman scattering in GaAs/AlAs multiple quantum wells with well widths varying between 100 and 1000 Angstrom. The hot phonon population observed by Raman scattering is found to decrease with the well width despite the fact that the hot electron temperature remains constant. The results are explained in terms of confinement of both electrons and optical phonons in quantum wells

  16. Studying the dynamics of colloidal particles with digital holographic microscopy and electromagnetic scattering solutions

    Directory of Open Access Journals (Sweden)

    V. N. Manoharan

    2011-09-01

    Full Text Available Digital holographic microscopy (DHM can measure the 3D positions as well as the scattering properties of colloidal particles in a single 2D image. We describe DHM and our analysis of recorded holograms with exact scattering solutions, which permit the measurement of 3D particle positions with ∼10 nm precision and millisecond time resolution, and discuss studies of the Brownian dynamics of clusters of spheres with DHM.

  17. Inelastic neutron scattering study on the polytypism of even-numbered n-alkanes

    Science.gov (United States)

    Kubota, Hideki; Kaneko, Fumitoshi; Kawaguchi, Tatsuya

    2005-02-01

    The thermodynamic properties of the two polytypes of n-hexatriacontane ( n- C36H74), single-layered structure Mon and double-layered structure Orth II, have been studied with incoherent inelastic neutron scattering and solubility measurements. The solubility measurements show that Orth II is more stable than Mon, because of its larger entropy. The neutron scattering measurements reveal that the vibrational modes of Orth II shift to the lower frequencies compared with those of Mon in the frequency region below 120 cm-1. The vibrational modes in this region make a dominant contribution to the vibrational entropy of a system, and the advantage of Orth II in vibrational entropy due to the low-frequency shifts is estimated to be 7.8 J K-1 mol-1 at 288 K under the harmonic approximation, which is in good agreement with the entropy difference between Mon and Orth II determined by solubility measurements. These results suggest that the relative stability of polytypic structures of long-chain compounds is mainly determined by the vibrational entropy of the low-frequency modes.

  18. Resonant x-ray scattering study of the antiferroelectric and ferrielectric phases in liquid crystal devices

    International Nuclear Information System (INIS)

    Matkin, L. S.; Watson, S. J.; Gleeson, H. F.; Pindak, R.; Pitney, J.; Johnson, P. M.; Huang, C. C.; Barois, P.; Levelut, A.-M.; Srajer, G.

    2001-01-01

    Resonant x-ray scattering has been used to investigate the interlayer ordering of the antiferroelectric and ferrielectric smectic C * subphases in a device geometry. The liquid crystalline materials studied contain a selenium atom and the experiments were carried out at the selenium K edge allowing x-ray transmission through glass. The resonant scattering peaks associated with the antiferroelectric phase were observed in two devices containing different materials. It was observed that the electric-field-induced antiferroelectric to ferroelectric transition coincides with the chevron to bookshelf transition in one of the devices. Observation of the splitting of the antiferroelectric resonant peaks as a function of applied field also confirmed that no helical unwinding occurs at fields lower than the chevron to bookshelf threshold. Resonant features associated with the four-layer ferrielectric liquid crystal phase were observed in a device geometry. Monitoring the electric field dependence of these ferrielectric resonant peaks showed that the chevron to bookshelf transition occurs at a lower applied field than the ferrielectric to ferroelectric switching transition

  19. Neutron scattering to study membrane systems: from lipid vesicles to living cells.

    Energy Technology Data Exchange (ETDEWEB)

    Nickels, Jonathan D. [ORNL; Chatterjee, Sneha [ORNL; Stanley, Christopher B. [ORNL; Qian, Shuo [ORNL; Cheng, Xiaolin [ORNL; Myles, Dean A A [ORNL; Standaert, Robert F. [ORNL; Elkins, James G. [ORNL; Katsaras, John [ORNL

    2017-03-01

    The existence and role of lateral lipid organization in biological membranes has been studied and contested for more than 30 years. Lipid domains, or rafts, are hypothesized as scalable compartments in biological membranes, providing appropriate physical environments to their resident membrane proteins. This implies that lateral lipid organization is associated with a range of biological functions, such as protein co-localization, membrane trafficking, and cell signaling, to name just a few. Neutron scattering techniques have proven to be an excellent tool to investigate these structural features in model lipids, and more recently, in living cells. I will discuss our recent work using neutrons to probe the structure and mechanical properties in model lipid systems and our current efforts in using neutrons to probe the structure and organization of the bilayer in a living cell. These efforts in living cells have used genetic and biochemical strategies to generate a large neutron scattering contrast, making the membrane visible. I will present our results showing in vivo bilayer structure and discuss the outlook for this approach.

  20. Scattering study at free air ionization chamber diaphragm

    International Nuclear Information System (INIS)

    Santos, Alexandre Lo Bianco dos

    2011-01-01

    The maim of this work consisted in the assessment of the correction factor for air kerma, due to scattered radiation in the diaphragm of the free-air ionization chamber model 481. LNMRl measurements were made to acquire x-ray spectra corresponding to the Qualities RQR-M, described in IEC 61627 standards (2005). These spectra were used as input data in the MC simulations. The operational range of energy spectra provide up to 35 keV. This energy range is typically used in diagnostic radiology, although there is not primary standard for air kerma. The determination of this factor is a fundamental process in the primary standardization of the air kerma. These factors were obtained by computer simulation using the Penelope code. The results are k RQR-M1 =0,9946, k RQR -M2 =0,9932, k RQR-M3 =0,9978 and k RQR-M4 =0,9885; with uncertainties of 0,007 and coverage factor equal to 2. lt can be concluded that, with respect to the diaphragm, the chamber can be used in the primary standard of air kerma. (author)

  1. Study of neutrino-electron scattering at LAMPF

    International Nuclear Information System (INIS)

    Potter, M.E.

    1987-01-01

    Using a beam stop source of ν e from stopped μ + A decay located at the Clinton B. Anderson Meson Physics Facility at the Los Alamos National Laboratory, a measurement of the reaction ν e + e - → ν e +e - was performed. In the Weinberg-Salam-Glashow model of electroweak interactions, the above reaction is mediated both by the exchange of a Z boson (neutral-current) and the exchange of a W boson (charged-current), and is thus sensitive to the interference between these two exchanges. A total of 304 ± 49 ν x e events are identified of which 254 ± 50 are attributed to ν e e elastic scattering. The observed event rate rules out the opposite sign of the interference by 4.6σ and is consistent with the interference predicted by the WSG model. The measured cross-section is σ(ν e e) = |11.8 ± 2.5(stat) ± 1.2(syst)| x 10 -42 cm 2 x E ν (GeV) with a measured Weinberg angle of sin 2 Θ ω = 0.31 ± 0.08 (stat) ±0.03(syst)

  2. Polarized neutron reflectivity and scattering studies of magnetic heterostructures

    International Nuclear Information System (INIS)

    Zabel, H; Theis-Broehl, K

    2003-01-01

    The current interest in the magnetism of ultrathin films and multilayers is driven by their manifold applications in the magneto-and spin-electronic areas, for instance as magnetic field sensors or as information storage devices. In this regard, there is a large interest in exploring spin structures and spin disorder at the interface of magnetic heterostructures, to investigate magnetic domains in thin films and superlattices, and to understand remagnetization processes of various laterally shaped magnetic nanostructures. Traditionally neutron scattering has played a dominant role in the determination of spin structures, phase transitions and magnetic excitations in bulk materials. Today, its potential for the investigation of thin magnetic films has to be redefined. Polarized neutron reflectivity (PNR) at small wavevectors can provide precise information on the magnetic field distribution parallel to the film plane and on layer resolved magnetization vectors. In addition, PNR is not only sensitive to structural interface roughness but also to the magnetic roughness. Furthermore, magnetic hysteresis measurements from polarized small angle Bragg reflections allows us to filter out correlation effects during magnetization reversals of magnetic stripes and islands. An overview is provided on most recent PNR investigations of magnetic heterostructures

  3. Optimalization study for ion-temperature measurements by means of Rutherford scattering

    International Nuclear Information System (INIS)

    Donne, A.J.H.; Barbian, E.P.

    1986-03-01

    Small-angle Rutherford scattering of energetic neutrals by plasma ions is governed by energy and momentum conservation. The FWHM of the scattering distibution reveals the ion temperature of the plasma. A feasibility study is performed to optimize the parameters in case Rutherford-scattering technique is applied to a medium-sized tokamak experiment. Together with a time-of-flight analyser with a high energy resolution of about 100, a 20 keV helium probing beam with a neutral current density of 10 A/m 2 can provide a detailed spectrum within 3 ms, from which the ion temperature can be extracted with an accuracy of better than 10%. The influence of plasma impurities and resonant charge exchange on the scattering process is discussed in detail. The good spatial resolution makes the method very suitable to investigate energy deposition profiles in the case of ion-cyclotron radiation applied to the plasma for the purpose of plasma heating. (orig.)

  4. Study of Quasielastic scattering for 7Li+159Tb at around- barrier energies

    Directory of Open Access Journals (Sweden)

    Mukherjee A.

    2017-01-01

    Full Text Available Quasielastic scattering cross sections for the reaction 7Li+159Tb have been measured at large backangles, at energies around the Coulomb barrier. The quasielastic barrier distribution has been extracted from the measured quasielastic scattering excitation function, including and excluding α particle contribution. The peak of the quasielastic barrier distribution including α particle contribution shows a shift towards higher energy compared to the peak of the distribution without α particles. The quasielastic barrier distribution when compared to the calculated fusion barrier distribution, appears to show reasonable agreement for the system.

  5. X-ray and neutron scattering on disordered nanosize clusters: a case study of lead-zirconate-titanate solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Frantti, Johannes; Fujioka, Yukari [Finnish Research and Engineering, Helsinki (Finland)

    2015-04-01

    Defects and frequently used defect models of solids are reviewed. Signatures for identifying the disorder from x-ray and neutron scattering data are given. To give illustrative examples how technologically important defects contribute to x-ray and neutron scattering numerical method able to treat non-periodical solids possessing several simultaneous defect types is given for simulating scattering in nanosize disordered clusters. The approach takes particle size, shape, and defects into account and isolates element specific signals. As a case study a statistical approximation model for lead-zirconate titanate [Pb(Zr{sub x}Ti{sub 1-x})O{sub 3}, PZT] is introduced. PZT is a material possessing several defect types, including substitutional, displacement and surface defects. Spatial composition variation is taken into account by introducing a model in which the edge lengths of each cell depend on the distribution of Zr and Ti ions in the cluster. Spatially varying edge lengths and angles is referred to as microstrain. The model is applied to compute the scattering from ellipsoid shaped PZT clusters and to simulate the structural changes as a function of average composition. Two-phase co-existence range, the so called morphotropic phase boundary composition is given correctly. The composition at which the rhombohedral and tetragonal cells are equally abundant was x ∼ 0.51. Selected x-ray and neutron Bragg reflection intensities and line shapes were simulated. Examples of the effect of size and shape of the scattering clusters on diffraction patterns are given and the particle dimensions, computed through Scherrer equation, are compared with the exact cluster dimensions. Scattering from two types of 180 domains in spherical particles, one type assigned to Ti-rich PZT and the second to the MPB and Zr-rich PZT, is computed. We show how the method can be used for modelling polarization reversal. (copyright 2015 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Structural studies using X-ray absorption and scattering techniques

    International Nuclear Information System (INIS)

    Ericson, Agneta.

    1989-01-01

    The thesis presents extended X-ray absorption fine structure, EXAFS, and large angle X-ray scattering, LAXS, techniques; instrumentation, data collection and reduction, and applications. These techniques have been used to determine the structures of magnesium halides and organomagnesium halides in diethyl ether and tetrahydrofuran solution. The iodides were used for the LAXS measurements and Br K edge EXAFS data were collected for the corresponding bromides. Two different complexes are present in the diethyl ether solution of magnesium iodide; a polymeric chain-type structure where magnesium is tetrahedrally coordinated, as well as dimeric complex with octahedrally coordinated magnesium. Solvated MgI + is the dominating species in tetrahydrofuran solution. The organomagnesium halides are present in diethyl ether solution as both solvated monomeric and dimeric complexes. Magnesium coordinates a halide ion, an alkyl or aryl group and four solvent molecules octahedrally in the monomeric complex. In the dimeric complex magnesium is octahedrally coordinated by two bridging halide ions, an alkyl or aryl group and three solvent molecules. The distribution of monomeric and dimeric complexes in various solutions are given by a dimerisation constant, K dl . The results indicate that the Schlenk equilibrium is present in these solutions, however, in an extended form. In diethyl ether solution, where MgX 2 does not dissociate, no MgX 2 complex and thereby no Schlenk equilibrium has been observed. In tetrahydrofuran solution MgI 2 has dissociated into mainly MgI + and I - . This indicates that the concentration of MgI 2 is low and that the Schlenk equilibrium should be expanded even further to include the dissociation equilibrium of the magnesium halide. In the thesis Fe K edge EXAFS data collected for the semireduced form of protein A of methane monooxygenase from Methylococcus capsulatus, are also presented. (139 refs.)

  7. Inelastic neutron scattering study of crystal field levels in PrOs4As12

    International Nuclear Information System (INIS)

    Chi, Songxue; Dai, Pengcheng; Barnes, T.F.E.; Kang, H. J.; Lynn, J. W.; Ye, Feng; Maple, M. B.

    2008-01-01

    We use neutron scattering to study the Pr 3+ crystalline electric field (CEF) excitations in the filled skutterudite PrOs 4 As 12 . By comparing the observed levels and their strengths under neutron excitation with the theoretical spectrum and neutron excitation intensities, we identify the Pr 3+ CEF levels, and show that the ground state is a magnetic Γ 4 (2) triplet, and the excited states Γ 1 , Γ 4 (1) and Γ 23 are at 0.4, 13 and 23 meV, respectively. A comparison of the observed CEF levels in PrOs 4 As 12 with the heavy fermion superconductor PrOs 4 Sb 12 reveals the microscopic origin of the differences in the ground states of these two filled skutterudites

  8. Study of the Boson Peak and Fragility of Bioprotectant Glass-Forming Mixtures by Neutron Scattering

    Directory of Open Access Journals (Sweden)

    F. Migliardo

    2013-01-01

    Full Text Available The biological relevance of trehalose, glycerol, and their mixtures in several anhydrobiotic and cryobiotic organisms has recently promoted both experimental and simulation studies. In addition, these systems are employed in different industrial fields, such as pharmaceutical and cosmetic industries, as additives in mixtures for cryopreservation and in several formulations. This review article shows an overview of Inelastic Neutron Scattering (INS data, collected at different temperature values by the OSIRIS time-of-flight spectrometer at the ISIS Facility (Rutherford Appleton Laboratory, Oxford, UK and by the IN4 and IN6 spectrometers at the Institut Laue Langevin (ILL, Grenoble, France, on trehalose/glycerol mixtures as a function of the glycerol content. The data analysis allows determining the Boson peak behavior and discussing the findings in terms of fragility in relation to the bioprotective action of trehalose and glycerol.

  9. Rutherford back-scattering and X-ray fluorescence for the study of corroded surfaces

    International Nuclear Information System (INIS)

    Chaudhri, M. Anwar

    2010-01-01

    A combination of Rutherford-Back-Scattering (RBS) and X-Ray Fluorescence Analysis (XRF) has been used to study the corroded inside surfaces of some tooth-paste tubes, which were causing a significant loss of the product. This greyish-brown, thin, corrosion layer on the inside of the tooth-paste tube is easily distinguishable from brand new, as well as from non-corroded used tubes, which are made of 99.7 % Al. The unused clean aluminium tube shows some copper traces (about 0.3 mg/cm 2 ) on the surface, which almost disappears from the surface of the non-corroded used tube but reappears, to a lesser extent, on the surface of the corroded tube. The corroded layer has been found to consist mainly of P and Ca (about 1 mg/cm 2 each) with smaller quantities of Na, Mg, Si, S and Cl. (authors)

  10. Study of "condensate" states in 12C and 16O by inelastic scattering

    International Nuclear Information System (INIS)

    Demyanova, A.S.; Ogloblin, A.A.; Goncharov, S.A.; Belyaeva, T.L.

    2008-01-01

    Study of some properties of the lowest states of 12 C, including the second 0 + , 7.65 MeV (Hoyle) state by inelastic scattering of alpha-particles and 3 He were carried out. Two independent methods of measuring the radii of the short-lived excited states based on the analysis of diffraction and rainbow patterns of the angular distributions were proposed. Both methods showed that Hoyle state radius is by factor ~ 1.2 – 1.3 larger than that of the ground state. 8 Be transfer reaction was identified. The probability of L = 0 configuration in Hoyle state occurred to be 3 times larger than in the ground state indicating to the significant presence of condensate configuration in the former one. (author)

  11. Femtosecond X-Ray Scattering Study of Ultrafast Photoinduced Structural Dynamics in Solvated [Co(terpy)2]2+

    DEFF Research Database (Denmark)

    Biasin, Elisa; Brandt van Driel, Tim; Kjær, Kasper Skov

    2016-01-01

    We study the structural dynamics of photoexcited [Co(terpy)2]2+ in an aqueous solution with ultrafast x-ray diffuse scattering experiments conducted at the Linac Coherent Light Source. Through direct comparisons with density functional theory calculations, our analysis shows that the photoexcitat......We study the structural dynamics of photoexcited [Co(terpy)2]2+ in an aqueous solution with ultrafast x-ray diffuse scattering experiments conducted at the Linac Coherent Light Source. Through direct comparisons with density functional theory calculations, our analysis shows...... find that the equilibrium bond-elongated structure of the high spin state is established on a single-picosecond time scale and that this state has a lifetime of ∼7 ps....

  12. Light Scattering Studies of Organic Field Effect Transistors

    Science.gov (United States)

    Adil, Danish

    fabrication methods. The work continues with a combined electro-optical study of the metal-semiconductor interface in OFETs. It is highly desirable that a method that can be used to understand the mechanisms of device performance degradation be developed. We demonstrate that the surface enhanced Raman (SERS) effect (at the metal-semiconductor interface) can serve as such a method. We first show how the Raman spectrum of a pristine pentacene (a common organic semiconductor) film is dramatically different from the spectrum collected when the film is probed through a metal contact. The spectrum collected from the contact region exhibits a change in peak intensities, peak positions, and an overall enhancement of signal intensity, all of which are direct evidence of the SERS effect. The SERS spectrum is then modeled by first principles density functional theory (DFT). The DFT calculations demonstrate that the SERS effect shows an extreme sensitivity to disorder in these semiconductor films. We further show how the SERS spectrum evolves after the device has been subjected to a bias-stress (i.e. applying both gate and drain voltages for an extended period of time). Devices that exhibit a strong degradation in performance also feature a concurrent change of the SERS spectrum. On the other hand, we see no change in the SERS spectrum of devices that exhibit stable operating characteristics. Thus, we confirm that the SERS spectrum can be used as a diagnostic tool for correlating transport properties to structural changes, if any, in organic semiconductor films. In conclusion, we develop a non-invasive opto-electronic visualization tool that can be used as an in-situ probe to characterize charge transport in organic semiconductor devices.

  13. Neutron Scattering Studies of Nano-Scale Wood-Water Interactions

    Science.gov (United States)

    Plaza Rodriguez, Nayomi Z.

    Understanding and controlling water in wood is critical to both improving forest products moisture durability and developing new sustainable forest products-based technologies. While wood is known to be hygroscopic, there is still a lack of understanding on the nanoscale wood-water interactions necessary for increased moisture-durability and dimensional stability. My PhD thesis focuses on the development and implementation of neutron scattering methods that can provide insight on both the structural and dynamical changes associated with these interactions so that products with improved moisture durability can be developed efficiently. Using small angle neutron scattering (SANS) and a custom-built in situ relative humidity chamber I studied the anisotropic moisture-induced swelling of wood nanostructure. First, I studied the effects of sample preparation by comparing SANS patterns of wiley milled wood and intact latewood cell walls, and found that scattering from intact wood provide more information about the spatial arrangement of the wood nanostructures inside the cell wall. Comparisons between SANS patterns from earlywood and latewood, also showed that the higher cell wall density of latewood cell walls results in patterns with more pronounced anisotropic features. Then, by measuring latewood loblolly pine sections obtained from the same growth ring and prepared in each of the primary wood planes, I tracked the cellulose elementary fibril spacing as a function of humidity in both intact and partially cut cell walls. These studies showed that even though swelling at the elementary fibril spacing is responsible for the majority of the transverse swelling observed at the S2 level, it is not primary plane dependent. Additionally, there were no differences in the elementary fibril spacing between partially-cut and intact cell walls, except at high humidity where the spacing in partially-cut cells was higher. SANS was also used to study the effects of two chemical

  14. Significance of scatter radar studies of E and F region irregularities at high latitudes

    International Nuclear Information System (INIS)

    Greenwald, R.A.

    1983-01-01

    This chapter considers the mechanisms by which electron density irregularities may be generated in the high latitude ionosphere and the techniques through which they are observed with ground base radars. The capabilities of radars used for studying these irregularities are compared with the capabilities of radars used for incoherent scatter measurements. The use of irregularity scatter techniques for dynamic studies of larger scale structured phenomena is discussed. Topics considered include E-region irregularities, observations with auroral radars, plasma drifts associated with a westward travelling surge, and ionospheric plasma motions associated with resonant waves. It is shown why high latitude F-region irregularity studies must be made in the HF frequency band (3-30 MHz). The joint use of the European Incoherent Scatter Association (EISCAT), STARE and SAFARI facilities is examined, and it is concluded that the various techniques will enhance each other and provide a better understanding of the various processes being studied

  15. Small-angle neutron scattering study of structural evolution of ...

    Indian Academy of Sciences (India)

    Rheology of these gels shows a strong dependence on varying pH or ... which regulate and control the functionality and stability of these molecules. Pro- .... The variation of crystallization fraction as a function of time for 1 wt% lysozyme.

  16. Neutron scattering studies on the high Tc superconductor YBa2Cu306+x

    International Nuclear Information System (INIS)

    Jurgens, M.J.G.M.

    1990-01-01

    The aim of the work described in this thesis is to clarify some of the magnetic aspects of high T c superconductors across the phase diagram as a function of doping and temperature, for which YBa 2 Cu 3 o 6+x has been chosen. Mainly the neutron scattering technique has been employed, which supplies a very powerful tool for this kind of research, for it directly shows the microscopic phenomena of the magnetism involved. First an introduction to the neutron scattering technique is given and a description of the spectrometers employed (ch. 2). The determination of the crystal structure of YBa 2 Cu 3 o 6+x is described, and the single crystals which were used during all the experiments on the magnetic properties as described in this thesis, are characterized (ch. 3). Ch. 4 deals with the phase diagram of the insulating antiferromagnetic phase in YBa 2 Cu 3 o 6+x , as obtained with neutron scattering. The inelastic scattering experiments on the magnetic excitations in this system are presented in ch. 5. In ch. 6 the total susceptibility, measure with a AQUID, is discussed. The local magnetizations, as determined with a polarized neutron scattering technique are the subject of ch. 7. (author). 254 refs.; 77 figs.; 25 tabs

  17. Neutron scattering study of the magnetism in a nanocrystalline/amorphous material

    Energy Technology Data Exchange (ETDEWEB)

    Rosov, N. [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Reactor Radiation Div.; Lynn, J.W. [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Reactor Radiation Div.]|[Univ. of Maryland, College Park, MD (United States). Dept. of Physics; Fish, G.E. [Allied Signal Inc., Morristown, NJ (United States)

    1995-12-31

    Recently developed nanocrystalline magnetic systems are of considerable interest fundamentally as well as technologically. One such material is Fe{sub 73.5}B{sub 9}Si{sub 13.5}Cu{sub 1}Nb{sub 3}, which can be produced by heat treating the amorphous precursor. This forms a noncrystalline phase with typical dimension of 350 {angstrom} as determined by neutron diffraction. Small angle neutron scattering (SANS) has been employed to investigate the properties of the nanocrystallized material over the temperature range from 10 K to 725 K, a regime where no significant structural changes are expected to occur. In zero field and low temperature (10 K) the authors obtained an isotropic scattering pattern. The application of a relatively modest field to sweep out the domains changed the scattering to a butterfly wings pattern typical of patterns dominated by magnetic elastic intensity. Up to 450 K this pattern changed only modestly, while for substantially higher temperatures the ratio of inelastic to elastic scattering increased rapidly as the magnetic phase transition of the intergranular component ({approx_equal} 575 K) was approached. Triple axis inelastic measurements showed that the majority of the magnetic inelastic scattering was from the nanocrystalline phase.

  18. Neutron scattering study of the magnetism in a nanocrystalline/amorphous material

    International Nuclear Information System (INIS)

    Rosov, N.

    1995-01-01

    Recently developed nanocrystalline magnetic systems are of considerable interest fundamentally as well as technologically. One such material is Fe 73.5 B 9 Si 13.5 Cu 1 Nb 3 , which can be produced by heat treating the amorphous precursor. This forms a noncrystalline phase with typical dimension of 350 angstrom as determined by neutron diffraction. Small angle neutron scattering (SANS) has been employed to investigate the properties of the nanocrystallized material over the temperature range from 10 K to 725 K, a regime where no significant structural changes are expected to occur. In zero field and low temperature (10 K) the authors obtained an isotropic scattering pattern. The application of a relatively modest field to sweep out the domains changed the scattering to a butterfly wings pattern typical of patterns dominated by magnetic elastic intensity. Up to 450 K this pattern changed only modestly, while for substantially higher temperatures the ratio of inelastic to elastic scattering increased rapidly as the magnetic phase transition of the intergranular component (≅ 575 K) was approached. Triple axis inelastic measurements showed that the majority of the magnetic inelastic scattering was from the nanocrystalline phase

  19. Defect and grain boundary scattering in tungsten: A combined theoretical and experimental study

    Science.gov (United States)

    Lanzillo, Nicholas A.; Dixit, Hemant; Milosevic, Erik; Niu, Chengyu; Carr, Adra V.; Oldiges, Phil; Raymond, Mark V.; Cho, Jin; Standaert, Theodorus E.; Kamineni, Vimal K.

    2018-04-01

    Several major electron scattering mechanisms in tungsten (W) are evaluated using a combination of first-principles density functional theory, a Non-Equilibrium Green's Function formalism, and thin film Kelvin 4-point sheet resistance measurements. The impact of grain boundary scattering is found to be roughly an order of magnitude larger than the impact of defect scattering. Ab initio simulations predict average grain boundary reflection coefficients for a number of twin grain boundaries to lie in the range r = 0.47 to r = 0.62, while experimental data can be fit to the empirical Mayadas-Schatzkes model with a comparable but slightly larger value of r = 0.69. The experimental and simulation data for grain boundary resistivity as a function of grain size show excellent agreement. These results provide crucial insights for understanding the impact of scaling of W-based contacts between active devices and back-end-of-line interconnects in next-generation semiconductor technology.

  20. Light Scattering Study of Mixed Micelles Made from Elastin-Like Polypeptide Linear Chains and Trimers

    Science.gov (United States)

    Terrano, Daniel; Tsuper, Ilona; Maraschky, Adam; Holland, Nolan; Streletzky, Kiril

    Temperature sensitive nanoparticles were generated from a construct (H20F) of three chains of elastin-like polypeptides (ELP) linked to a negatively charged foldon domain. This ELP system was mixed at different ratios with linear chains of ELP (H40L) which lacks the foldon domain. The mixed system is soluble at room temperature and at a transition temperature (Tt) will form swollen micelles with the hydrophobic linear chains hidden inside. This system was studied using depolarized dynamic light scattering (DDLS) and static light scattering (SLS) to determine the size, shape, and internal structure of the mixed micelles. The mixed micelle in equal parts of H20F and H40L show a constant apparent hydrodynamic radius of 40-45 nm at the concentration window from 25:25 to 60:60 uM (1:1 ratio). At a fixed 50 uM concentration of the H20F, varying H40L concentration from 5 to 80 uM resulted in a linear growth in the hydrodynamic radius from about 11 to about 62 nm, along with a 1000-fold increase in VH signal. A possible simple model explaining the growth of the swollen micelles is considered. Lastly, the VH signal can indicate elongation in the geometry of the particle or could possibly be a result from anisotropic properties from the core of the micelle. SLS was used to study the molecular weight, and the radius of gyration of the micelle to help identify the structure and morphology of mixed micelles and the tangible cause of the VH signal.

  1. X-ray magnetic scattering in SDW Cr - ab initio study

    International Nuclear Information System (INIS)

    Takahashi, M.; Igarashi, J.-I.; Hirai, K.

    2004-01-01

    Full text: Resonant x-ray scattering at the K-edge of transition metal atom has attracted much attention as a powerful tool for obtaining information on magnetic or orbital properties of 3d electrons. Recently Mannix et al. performed the x-ray magnetic scattering experiment in SDW Chromium and observed the finite scattering intensity with resonant enhancement at Cr K-edge on the SDW magnetic spot (0, 0, 1 ±δ). Applying ab-initio band structure calculation based on the local spin density approximation, we analyze the scattering spectra and elucidate the mechanism of the resonant enhancement in connection with the electronic structure. We assumed the bcc structure with the lattice constant a = 5.45a 0 and the SDW wavelength λ SDW = 20a, which are nearly equilibrium value at the spin-flip temperature T SF = 122K. The K-edge x-ray absorption and scattering spectra are calculated using Fermi's golden rule. We evaluate the non-resonant scattering amplitude within the spherical and dipolar approximations for spin and orbital moment contributions, respectively. The calculated absorption spectra are in good agreement with the experiment. This may assure the validity of the calculation. We obtained finite scattering amplitude with resonant enhancement at the K-edge. The calculated photon energy dependence of the scattering intensity shows good agreement with the experiment. The contribution of the 3d and 4p orbital moments to the non-resonant scattering amplitude is negligible in consequence of the smallness of their values, which are l max d ∼ 0.006ℎ and l max p ∼ 0.00007ℎ. On the other hand, although the 3d and 4p orbital moments are infinitesimal, they play important role on the resonant enhancement, which occurs through the 1s - 4p dipole transition and reflects the 4p orbital polarization. The 4p orbital polarization is caused by the on-site spin-orbit interaction in 4p orbital itself and the hybridization of the 4p orbital with the 3d orbital at neighboring

  2. Studies of coherent/Compton scattering method for bone mineral content measurement

    International Nuclear Information System (INIS)

    Sakurai, Kiyoko; Iwanami, Shigeru; Nakazawa, Keiji; Matsubayashi, Takashi; Imamura, Keiko.

    1980-01-01

    A measurement of bone mineral content by a coherent/Compton scattering method was described. A bone sample was irradiated by a collimated narrow beam of 59.6 keV gamma-rays emitted from a 300 mCi 241 Am source, and the scattered radiations were detected using a collimated pure germanium detector placed at 90 0 to the incident beam. The ratio of coherent to Compton peaks in a spectrum of the scattered radiations depends on the bone mineral content of the bone sample. The advantage of this method is that bone mineral content of a small region in a bone can be accurately measured. Assuming that bone consists of two components, protein and bone mineral, and that the mass absorption coefficient for Compton scattering is independent of material, the coherent to Compton scattering ratio is linearly related to the percentage in weight of bone mineral. A calibration curve was obtained by measuring standard samples which were mixed with Ca 3 (PO 4 ) 2 and H 2 O. The error due to the assumption about the mass absorption coefficient for Compton scattering and to the difference between true bone and standard samples was estimated to be less than 3% within the range from 10 to 60% in weight of bone mineral. The fat in bone affects an estimated value by only 1.5% when it is 20% in weight. For the clinical application of this method, the location to be analyzed should be selected before the measurement with two X-ray images viewed from the source and the detector. These views would be also used to correct the difference in absorption between coherent and Compton scattered radiations whose energies are slightly different from each other. The absorbed dose to the analyzed region was approximately 150 mrad. The time required for one measurement in this study was about 10 minutes. (author)

  3. Study of scattering cross section of a plasma column using Green's function volume integral equation method

    Science.gov (United States)

    Soltanmoradi, Elmira; Shokri, Babak

    2017-05-01

    In this article, the electromagnetic wave scattering from plasma columns with inhomogeneous electron density distribution is studied by the Green's function volume integral equation method. Due to the ready production of such plasmas in the laboratories and their practical application in various technological fields, this study tries to find the effects of plasma parameters such as the electron density, radius, and pressure on the scattering cross-section of a plasma column. Moreover, the incident wave frequency influence of the scattering pattern is demonstrated. Furthermore, the scattering cross-section of a plasma column with an inhomogeneous collision frequency profile is calculated and the effect of this inhomogeneity is discussed first in this article. These results are especially used to determine the appropriate conditions for radar cross-section reduction purposes. It is shown that the radar cross-section of a plasma column reduces more for a larger collision frequency, for a relatively lower plasma frequency, and also for a smaller radius. Furthermore, it is found that the effect of the electron density on the scattering cross-section is more obvious in comparison with the effect of other plasma parameters. Also, the plasma column with homogenous collision frequency can be used as a better shielding in contrast to its inhomogeneous counterpart.

  4. Monte Carlo evaluation of scattering correction methods in 131I studies using pinhole collimator

    International Nuclear Information System (INIS)

    López Díaz, Adlin; San Pedro, Aley Palau; Martín Escuela, Juan Miguel; Rodríguez Pérez, Sunay; Díaz García, Angelina

    2017-01-01

    Scattering is quite important for image activity quantification. In order to study the scattering factors and the efficacy of 3 multiple window energy scatter correction methods during 131 I thyroid studies with a pinhole collimator (5 mm hole) a Monte Carlo simulation (MC) was developed. The GAMOS MC code was used to model the gamma camera and the thyroid source geometry. First, to validate the MC gamma camera pinhole-source model, sensibility in air and water of the simulated and measured thyroid phantom geometries were compared. Next, simulations to investigate scattering and the result of triple energy (TEW), Double energy (DW) and Reduced double (RDW) energy windows correction methods were performed for different thyroid sizes and depth thicknesses. The relative discrepancies to MC real event were evaluated. Results: The accuracy of the GAMOS MC model was verified and validated. The image’s scattering contribution was significant, between 27-40 %. The discrepancies between 3 multiple window energy correction method results were significant (between 9-86 %). The Reduce Double Window methods (15%) provide discrepancies of 9-16 %. Conclusions: For the simulated thyroid geometry with pinhole, the RDW (15 %) was the most effective. (author)

  5. Small-angle x-ray scattering in amorphous silicon: A computational study

    Science.gov (United States)

    Paudel, Durga; Atta-Fynn, Raymond; Drabold, David A.; Elliott, Stephen R.; Biswas, Parthapratim

    2018-05-01

    We present a computational study of small-angle x-ray scattering (SAXS) in amorphous silicon (a -Si) with particular emphasis on the morphology and microstructure of voids. The relationship between the scattering intensity in SAXS and the three-dimensional structure of nanoscale inhomogeneities or voids is addressed by generating large high-quality a -Si networks with 0.1%-0.3% volume concentration of voids, as observed in experiments using SAXS and positron annihilation spectroscopy. A systematic study of the variation of the scattering intensity in the small-angle scattering region with the size, shape, number density, and the spatial distribution of the voids in the networks is presented. Our results suggest that the scattering intensity in the small-angle region is particularly sensitive to the size and the total volume fraction of the voids, but the effect of the geometry or shape of the voids is less pronounced in the intensity profiles. A comparison of the average size of the voids obtained from the simulated values of the intensity, using the Guinier approximation and Kratky plots, with that of the same from the spatial distribution of the atoms in the vicinity of void surfaces is presented.

  6. Charged defects in chalcogenide vitreous semiconductors studied with combined Raman scattering and PALS methods

    International Nuclear Information System (INIS)

    Kavetskyy, T.; Vakiv, M.; Shpotyuk, O.

    2007-01-01

    A combination of Raman scattering and positron annihilation lifetime spectroscopy (PALS) techniques to study charged defects in chalcogenide vitreous semiconductors (ChVSs) was applied for the first time in this study. In the case of Ge 15.8 As 21 S 63.2 glass, it is found that the main radiation-induced switching of heteropolar Ge-S bonds into heteropolar As-S ones, previously detected by IR fast Fourier transform spectroscopy, can also be identified by Raman spectroscopy in the depolarized configuration. Results obtained by Raman scattering are in good agreement with PALS data for the investigated glass composition

  7. Charged defects in chalcogenide vitreous semiconductors studied with combined Raman scattering and PALS methods

    Energy Technology Data Exchange (ETDEWEB)

    Kavetskyy, T.; Vakiv, M. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine); Shpotyuk, O. [Lviv Institute of Materials of SRC ' Carat' , 202 Stryjska str., Lviv, UA-79031 (Ukraine)], E-mail: shpotyuk@novas.lviv.ua

    2007-04-15

    A combination of Raman scattering and positron annihilation lifetime spectroscopy (PALS) techniques to study charged defects in chalcogenide vitreous semiconductors (ChVSs) was applied for the first time in this study. In the case of Ge{sub 15.8}As{sub 21}S{sub 63.2} glass, it is found that the main radiation-induced switching of heteropolar Ge-S bonds into heteropolar As-S ones, previously detected by IR fast Fourier transform spectroscopy, can also be identified by Raman spectroscopy in the depolarized configuration. Results obtained by Raman scattering are in good agreement with PALS data for the investigated glass composition.

  8. X-ray scattering studies of non-equilibrium ordering processes

    International Nuclear Information System (INIS)

    Nagler, S.E.

    1991-01-01

    We report on the progress of the project entitled ''X-ray Scattering Studies of Non-Equilibrium Ordering Processes.'' The past year has seen continued progress in the study of kinetic effects in metallic binary alloys and polymers. In addition, work has begun on a low dimensional CDW system: blue bronze. A sample chamber has been constructed to perform small angle neutron scattering measurements on a model quantum system with phase separation: solid He3/He4. Work is continuing on magnetic systems. Planned future experiments include an investigation of crystallization in Rubidium

  9. A numerical study of super-resolution through fast 3D wideband algorithm for scattering in highly-heterogeneous media

    KAUST Repository

    Létourneau, Pierre-David

    2016-09-19

    We present a wideband fast algorithm capable of accurately computing the full numerical solution of the problem of acoustic scattering of waves by multiple finite-sized bodies such as spherical scatterers in three dimensions. By full solution, we mean that no assumption (e.g. Rayleigh scattering, geometrical optics, weak scattering, Born single scattering, etc.) is necessary regarding the properties of the scatterers, their distribution or the background medium. The algorithm is also fast in the sense that it scales linearly with the number of unknowns. We use this algorithm to study the phenomenon of super-resolution in time-reversal refocusing in highly-scattering media recently observed experimentally (Lemoult et al., 2011), and provide numerical arguments towards the fact that such a phenomenon can be explained through a homogenization theory.

  10. Annual report on neutron scattering studies in JAERI, July, 1976 - June, 1977

    International Nuclear Information System (INIS)

    Hamaguchi, Yoshikazu; Iizumi, Masashi; Endoh, Yasuo

    1977-11-01

    Neutron scattering studies carried out by Division of Physics, JAERI and by several universities utilizing facilities in Tokai are reported for the period of July, 1976 to June, 1977. The report contains 39 short papers submitted by authors on their individual studies. (auth.)

  11. Inversion of the pahse diagram in polymer blends studied by small-angle neutron scattering

    International Nuclear Information System (INIS)

    Jinnai, Hiroshi; Hasegawa, Hirokazu; Hashimoto, Takeji; Han, C.C.

    1993-01-01

    The miscibility of an amorphous mixture of normal (protonated) polybutadiend (HPB) and perdeuterated polybutadiene (DPB) has been extensively studied and was characterized by an upper critical solution temperature (UCST). In this study the miscibility of HPB and DPB as a function of temperature was studied by small-angle neutron scattering (SANS). The vinyl component of the DPB was held constant at 16%, while the vinyl frantion of the HPB was varied from 17-80%. The binary interaction parameter, χ, was obtained. The mixtures of DPB and HPB with 17-39% vinyl show UCST behaviors; i.e., χ increases with decreasing temperature. The mixture of DPB and HPB with 52% vinyl was found to have almost no temperature dependence. However, the mixture of DPB and HPB with 65-80% show a lower critical solution temperature (LCST) behavior; i.e., χ increases with increasing temperature. This inversion of the phase diagram from UCST to LCST has never been observed. (author)

  12. Protein aggregation studied by forward light scattering and light transmission analysis

    Science.gov (United States)

    Penzkofer, A.; Shirdel, J.; Zirak, P.; Breitkreuz, H.; Wolf, E.

    2007-12-01

    The aggregation of the circadian blue-light photo-receptor cryptochrome from Drosophila melanogaster (dCry) is studied by transmission and forward light scattering measurement in the protein transparent wavelength region. The light scattering in forward direction is caused by Rayleigh scattering which is proportional to the degree of aggregation. The light transmission through the samples in the transparent region is reduced by Mie light scattering in all directions. It depends on the degree of aggregation and the monomer volume fill factor of the aggregates (less total scattering with decreasing monomer volume fill factor of protein globule) allowing a distinction between tightly packed protein aggregation (monomer volume fill factor 1) and loosely packed protein aggregation (monomer volume fill factor less than 1). An increase in aggregation with temperature, concentration, and blue-light exposure is observed. At a temperature of 4 °C and a protein concentration of less than 0.135 mM no dCry aggregation was observed, while at 24 °C and 0.327 mM gelation occurred (loosely packed aggregates occupying the whole solution volume).

  13. Effect of static scatterers in laser speckle contrast imaging: an experimental study on correlation and contrast

    Science.gov (United States)

    Vaz, Pedro G.; Humeau-Heurtier, Anne; Figueiras, Edite; Correia, Carlos; Cardoso, João

    2018-01-01

    Laser speckle contrast imaging (LSCI) is a non-invasive microvascular blood flow assessment technique with good temporal and spatial resolution. Most LSCI systems, including commercial devices, can perform only qualitative blood flow evaluation, which is a major limitation of this technique. There are several factors that prevent the utilization of LSCI as a quantitative technique. Among these factors, we can highlight the effect of static scatterers. The goal of this work was to study the influence of differences in static and dynamic scatterer concentration on laser speckle correlation and contrast. In order to achieve this, a laser speckle prototype was developed and tested using an optical phantom with various concentrations of static and dynamic scatterers. It was found that the laser speckle correlation could be used to estimate the relative concentration of static/dynamic scatterers within a sample. Moreover, the speckle correlation proved to be independent of the dynamic scatterer velocity, which is a fundamental characteristic to be used in contrast correction.

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

    International Nuclear Information System (INIS)

    Boulanger, Joan; Liu, Fengshan; El Akel, Azad; Charette, Andre

    2006-01-01

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

  15. Critical scattering

    International Nuclear Information System (INIS)

    Stirling, W.G.; Perry, S.C.

    1996-01-01

    We outline the theoretical and experimental background to neutron scattering studies of critical phenomena at magnetic and structural phase transitions. The displacive phase transition of SrTiO 3 is discussed, along with examples from recent work on magnetic materials from the rare-earth (Ho, Dy) and actinide (NpAs, NpSb, USb) classes. The impact of synchrotron X-ray scattering is discussed in conclusion. (author) 13 figs., 18 refs

  16. Neutron scattering study of the magnetic correlations of iron rich Fe-Zr glasses

    International Nuclear Information System (INIS)

    Fernandez-Baca, J.A.; Rhyne, J.J.; Erwin, R.W.; Fish, G.E.

    1988-01-01

    Small angle neutron scattering (SANS) and polarized-beam spin rotation measurements show that amorphous Fe/sub 80/Zr/sub 10/ does not exhibit conventional long range ferromagnetic order below T/sub C/. The SANS measurements show the existence of two characteristic length scales; one provides evidence of relatively large spin clusters, while the other is characteristic of the spin dynamics. 4 refs., 3 figs

  17. Raman scattering studies of mobile ions in superionic conductor hollandites

    International Nuclear Information System (INIS)

    Shibata, Y.; Suemoto, T.; Ishigame, M.

    1986-01-01

    The Raman spectra of the superionic conductors K/sub 1.6/Mg/sub 0.8/Ti/sub 7.2/O 16 , Cs/sub 1.2/Mg/sub 0.6/Ti/sub 7.4/O 16 , and (KTl)/sub 1.6/Mg/sub 0.8/Ti/sub 7.2/O 16 are measured in the frequency range from 5 to 1000 cm -1 . In the range from 100 to 1000 cm -1 Raman spectra hardly show alkali ion dependence. On the contrary, in the frequency range from 5 to 100 cm -1 , an additional Raman band is observed. This Raman band shows alkali ion dependence. By using the Frenkel-Kontorova model for the hollandite crystal with the given configuration of the mobile ions, it is found that the dependence of vibrational frequency of mobile ions with kinds of alkali ion is well explained and that the concept of 'super unit cell' that is introduced by Beyeler is very useful to explain the Raman bands which are observed below 100 cm -1 in hollandite crystals. (author)

  18. Small-angle X-ray scattering studies of thermally-induced globular protein gels

    International Nuclear Information System (INIS)

    Clark, A.H.; Tuffnell, C.D.

    1980-01-01

    Small-angle X-ray scattering has been applied to gels formed by heating globular proteins, in aqueous solution, above their unfolding temperatures. A number of BSA gels, previously characterised by electron microscopy, have been studied, and by setting up theoretical models for the scattering process, the X-ray data have been shown to be consistent with the microscope conclusions regarding network structure. It is concluded that the networks form by a linearly-directed aggregation of unfolded, disc-like, protein molecules, three-dimensional geometry being achieved by occasional branching, and/or cross-linking. Long-range inhomogeneities in network structure, easily observed by electron microscopy, and correlated with variations in pH or ionic strength, have an effect on X-ray scattering, and hence the X-ray method is sensitive not only to different network strand thicknesses, but to different degrees of uniformity as well. (author)

  19. Small-angle neutron scattering and cyclic voltammetry study on electrochemically oxidized and reduced pyrolytic carbon

    International Nuclear Information System (INIS)

    Braun, A.; Kohlbrecher, J.; Baertsch, M.; Schnyder, B.; Koetz, R.; Haas, O.; Wokaun, A.

    2004-01-01

    The electrochemical double layer capacitance and internal surface area of a pyrolytic carbon material after electrochemical oxidation and subsequent reduction was studied with cyclic voltammetry and small-angle neutron scattering. Oxidation yields an enhanced internal surface area (activation), and subsequent reduction causes a decrease of this internal surface area. The change of the Porod constant, as obtained from small-angle neutron scattering, reveals that the decrease in internal surface area is not caused merely by a closing or narrowing of the pores, but by a partial collapse of the pore network

  20. Diffuse x-ray scattering study of interfacial structure of self-assembled conjugated polymers

    International Nuclear Information System (INIS)

    Wang Jun; Park, Y.J.; Lee, K.-B.; Hong, H.; Davidov, D.

    2002-01-01

    The interfacial structures of self-assembled heterostructures through alternate deposition of conjugated and nonconjugated polymers were studied by x-ray reflectivity and nonspecular scattering. We found that the interfacial width including the effects of both interdiffusion and interfacial roughness (correlated) was mainly contributed by the latter one. The self-assembled deposition induced very small interdiffusion between layers. The lateral correlation length ξ parallel grew as a function of deposition time (or film thickness) described by a power law ξ parallel ∝t β/H and was also observed from the off-specular scattering

  1. Hydrogen potential in β-V2H studied by deep inelastic neutron scattering

    International Nuclear Information System (INIS)

    Hempelmann, R.; Price, D.L.; Reiter, G.; Richter, D.

    1989-02-01

    Two complementary techniques of deep inelastic neutron scattering were used to study hydrogen in β-V 2 H: (i) by means of neutron vibrational spectroscopy we measured hydrogen vibrations up to the fourteenth order; from these data we derived the effective single-particle potential, the shape of which is a parabola with a flattened bottom, and the hydrogen wave functions. (ii) By means of neutron Compton scattering we determined the kinetic of energy of the hydrogen; the value agrees with that calculated from the vibrational ground-state wave function. 6 refs., 5 figs

  2. Study of the Effect of Active Regions on the Scattering Polarization in the Solar Corona

    Science.gov (United States)

    Derouich, M.; Badruddin

    2018-03-01

    The solar photospheric/chromospheric light exciting atoms/ions is not homogeneous because of the presence of active regions (ARs). The effect of ARs on the scattering polarization at the coronal level is an important ingredient for a realistic determination of the magnetic field. This effect is usually disregarded or mixed with other effects in the sense that the degree of its importance is not well known. The aim of this paper is to study the effect of atmospheric inhomogeneities on the coronal scattering polarization. We determined quantitatively the importance of the atmospheric inhomogeneities by using given geometries of solar ARs (plages and sunspots).

  3. Small-angle neutron scattering studies of nonionic surfactant: Effect ...

    Indian Academy of Sciences (India)

    celle above a concentration called critical micelle concentration (CMC) where their properties are different from those of the ... It is well-known that SANS is an ideal technique to study the micellar structure of surfactants [8,9] and this has also ... ment at the Dhruva reactor, Mumbai [11]. The mean wavelength of the incident.

  4. Title: Studies on drug switchability showed heterogeneity in methodological approaches: a scoping review.

    Science.gov (United States)

    Belleudi, Valeria; Trotta, Francesco; Vecchi, Simona; Amato, Laura; Addis, Antonio; Davoli, Marina

    2018-05-16

    Several drugs share the same therapeutic indication, including those undergoing patent expiration. Concerns on the interchangeability are frequent in clinical practice, challenging the evaluation of switchability through observational research. To conduct a scoping review of observational studies on drug switchability to identify methodological strategies adopted to deal with bias and confounding. We searched PubMed, EMBASE, and Web of Science (updated 1/31/2017) to identify studies evaluating switchability in terms of effectiveness/safety outcomes or compliance. Three reviewers independently screened studies extracting all characteristics. Strategies to address confounding, particularly, previous drug use and switching reasons were considered. All findings were summarized in descriptive analyses. Thirty-two studies, published in the last 10 years, met the inclusion criteria. Epilepsy, cardiovascular and rheumatology were the most frequently represented clinical areas. 75% of the studies reported data on effectiveness/safety outcomes. The most frequent study design was cohort (65.6%) followed by case-control (21.9%) and self-controlled (12.5%). Case-control and case-crossover studies showed homogeneous methodological strategies to deal with bias and confounding. Among cohort studies, the confounding associated with previous drug use was addressed introducing variables in multivariate model (47.3%) or selecting only adherent patients (14.3%). Around 30% of cohort studies did not report reasons for switching. In the remaining 70%, clinical parameters or previous occurrence of outcomes were measured to identify switching connected with lack of effectiveness or adverse events. This study represents a starting point for researchers and administrators who are approaching the investigation and assessment of issues related to interchangeability of drugs. Copyright © 2018. Published by Elsevier Inc.

  5. Microscope Raman scattering and X-ray diffraction study of near-stoichiometric Ti:LiNbO3 waveguides

    International Nuclear Information System (INIS)

    Zhang, De-Long; Siu, G.G.; Pun, E.Y.B.

    2005-01-01

    The crystalline phase within guiding layers of near-stoichiometric strip and planar Ti:LiNbO 3 wave-guides, prepared by the method of simultaneous work of vapour transport equilibration (VTE) treatment and indiffusion of Ti film, was studied by combined confocal microscope Raman scattering and X-ray powder diffraction. The results show that the strip and planar waveguide layers still retain the LiNbO 3 phase and no other non-LiNbO 3 phases can be identified within the guiding layer. Li/Nb ratios inside and outside the strip and planar waveguide layers were determined from the microscope Raman scattering results and compared to those obtained from the measured optical absorption edge. It is shown that the Li/Nb ratios are homogeneous within the waveguide layer and are close inside and outside the waveguide layer. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. General shape and hapten-induced conformational changes of pig anti-dinitrophenyl antibody. A small-angle scattering study

    International Nuclear Information System (INIS)

    Cher, L.; Gladkikh, I.A.; Franek, F.; Kunchenko, A.B.; Ostanevich, Yu.M.

    1980-01-01

    Pig anti-dinitrophenyl antibodies were studied by neutron and X-ray small-angle scattering. Observed scattering curves show that the shapes of two antibody types, precipitating and non-precipitating, are similar, however the latter being more compact. A hapten binding induced conformational change of antibody is observed. This conformational change might be described as a contraction of the whole molecule via similarity transformation. The spatial models of pig antibody molecule based on the existing experimental data were designed. Most probable models have a cavity in the Fsub(c) part and the Fsub(ab) parts are either fully extended or slightly bent down to the Fsub(c) part

  7. Surface-enhanced Raman scattering and density functional theory study of 1,4-benzenedithiol and its silver complexes.

    Science.gov (United States)

    Shao, Yangfan; Li, Chongyang; Feng, Yuanming; Lin, Wang

    2013-12-01

    This paper experimentally and theoretically investigated Raman and surface-enhanced Raman scattering (SERS) of 1,4-benzenedithiol (1,4-BDT). Density functional theory methods were used to study Raman scattering spectra of isolated 1,4-BDT and 1,4-BDT-Agn (n=2,4,6) complexes with B3LYP/6-311+g(d)(C,H,S)/Lanl2dz(Ag) basis set. A full assignment of the Raman spectrum of 1,4-BDT has been made based on the DFT analysis. The calculated data showed good agreement with experimental observations. The adsorption sites, metal cluster size, and HOMO-LUMO energies are discussed to give insight in the SERS mechanisms for 1,4-BDT molecules. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Real-time x-ray scattering study of the initial growth of organic crystals on polymer brushes

    Energy Technology Data Exchange (ETDEWEB)

    An, Sung Yup; Ahn, Kwangseok; Kim, Doris Yangsoo; Lee, Dong Ryeol, E-mail: drlee@ssu.ac.kr [Department of Physics, Soongsil University, Seoul 156-743 (Korea, Republic of); Lee, Hyun-Hwi [Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Cho, Jeong Ho, E-mail: jhcho94@skku.edu [Department of Chemical Engineering, SKKU Advanced Institute of Nanotechnology (SAINT) and Center for Human Interface Nano Technology (HINT), Sungkyunkwan University, Suwon 440-476 (Korea, Republic of)

    2014-04-21

    We studied the early-stage growth structures of pentacene organic crystals grown on polymer brushes using real-time x-ray scattering techniques. In situ x-ray reflectivity and atomic force microscopy analyses revealed that at temperatures close to the glass transition temperature of polymer brush, the pentacene overlayer on a polymer brush film showed incomplete condensation and 3D island structures from the first monolayer. A growth model based on these observations was used to quantitatively analyze the real-time anti-Bragg x-ray scattering intensities measured during pentacene growth to obtain the time-dependent layer coverage of the individual pentacene monolayers. The extracted total coverage confirmed significant desorption and incomplete condensation in the pentacene films deposited on the polymer brushes. These effects are ascribed to the change in the surface viscoelasticity of the polymer brushes around the glass transition temperature.

  9. Study of particles in solution by small angle x-ray scattering

    International Nuclear Information System (INIS)

    Itri, R.

    1986-01-01

    The implantation of SAXS technique is presented, and mycellas in solution of the dodecyl sodium sulfate SLS/water system are studied. A synthesis of SAXS theory to study parameters such as, volume, radii of gyration and specific surface and distribution function of the distance of homogenous and inhomogeneous particles is also presented. The technique was implanted by the study of a vitreous coal sample with voids in amorphous matrix. Computer programs were used for data treatment. It was concluded that the void configuration must be an oblate ellipsoid with rippled external surface and radii of gyration of ∼20A . The study of mycellas in solution of the SLL/H 2 O binary system showed spherical mycellas with paraffinic radii of 16A and total radii of 25.5 A. Interaction effects start to appear in 15% SLS concentrations. The change in the scattering curve occurs due to the interactions between mycellas. The isotropic-nematic transition in the ternary system by decanol addition was also investigated. (M.C.K.) [pt

  10. Contesting the "Nature" Of Conformity: what Milgram and Zimbardo's studies really show.

    Directory of Open Access Journals (Sweden)

    S Alexander Haslam

    Full Text Available Understanding of the psychology of tyranny is dominated by classic studies from the 1960s and 1970s: Milgram's research on obedience to authority and Zimbardo's Stanford Prison Experiment. Supporting popular notions of the banality of evil, this research has been taken to show that people conform passively and unthinkingly to both the instructions and the roles that authorities provide, however malevolent these may be. Recently, though, this consensus has been challenged by empirical work informed by social identity theorizing. This suggests that individuals' willingness to follow authorities is conditional on identification with the authority in question and an associated belief that the authority is right.

  11. Experimental study of the molecular beam destruction by beam-beam and beam-background scattering

    International Nuclear Information System (INIS)

    Bossel, U.; Dettleff, G.

    1974-01-01

    The extraction of flow properties related to the molecular motion normal to stream lines of an expanding gas jet from observed intensity profiles of supersonic beams is critically assessed. The perturbation of the profile curves by various effects is studied for a helium beam. Exponential laws appear to describe scattering effects to a satisfactory degree

  12. [Intermediate energy studies of polarization transfer, polarized deuteron scattering, and (p,π+-) reactions: Rapporteur's report

    International Nuclear Information System (INIS)

    Moss, J.M.

    1985-01-01

    An overview of intermediate energy (80 to 1000 MeV) study contributions to the International Polarization Symposium in Osaka, Japan, August 1985 is presented in this report. Contributions fall into three categories: polarization transfer, polarized deuteron scattering and polarized (p,π +- ) reactions

  13. Neutron Scattering Studies of the Ionic Conductor LiI D2O

    DEFF Research Database (Denmark)

    Andersen, N. H.; Kjems, Jørgen; Poulsen, Finn Willy

    1982-01-01

    The structural properties of the ionic conductor LiID2O have been studied by neutron scattering. The cubic room temperature α-phase, Pm3m, is disordered both with respect to the occupation of the Li+-positions and to the orientations of the water molecules. A first order phase transition from the α...

  14. Magnetic Dimer Excitations in Cs3Cr2CI9 Studied by Neutron Scattering

    DEFF Research Database (Denmark)

    Leuenberger, Bruno; Güdel, Hans U.; Kjems, Jørgen

    1985-01-01

    The energy dispersion of the singlet-triplet dimer excitation in Cs3Cr2CI9h as been studied by inelastic neutron scattering (INS) at temperatures down to 1.3 K. The results can be accounted for by using a completely isotropic Heisenberg Hamiltonian in the random phase approximation (RPA). Only...

  15. Solution scattering studies on a virus capsid protein as a building block for nanoscale assemblies

    NARCIS (Netherlands)

    Comellas Aragones, M.; Comellas-Aragones, Marta; Sikkema, Friso D.; Delaittre, Guillaume; Terry, Ann E.; King, Stephen M.; Visser, Dirk; Heenan, Richard K.; Nolte, Roeland J.M.; Cornelissen, Jeroen Johannes Lambertus Maria; Feiters, Martin C.

    2011-01-01

    Self-assembled protein cages are versatile building blocks in the construction of biomolecular nanostructures. Because of the defined assembly behaviour the cowpea chlorotic mottle virus (CCMV) protein is often used for such applications. Here we report a detailed solution scattering study of the

  16. Annual report on neutron scattering studies in JAERI, July 1, 1977 - August 31, 1978

    International Nuclear Information System (INIS)

    Hamaguchi, Yoshikazu; Iizumi, Masashi; Endoh, Yasuo

    1978-12-01

    Neutron scattering studies carried out by Division of Physics, JAERI, and several universities with neutron beam facilities at JRR-2 and 3 in Tokai are described for the period from July, 1977 to August, 1978. Contents are 51 individual reports and list of publicatios during the period. (author)

  17. Elastic scattering study of three 4n nuclei systems above the Coulomb barrier

    International Nuclear Information System (INIS)

    Ashok Kumar; Sarita Kumar; Sunita Kumar

    2000-01-01

    A comprehensive study of elastic scattering of 4n nuclei, namely 16 O + 40 Ca, 24 Mg + 24 Mg and 32 S + 28 Si is carried out at various incident energies near and above the Coulomb barrier using a semi microscopic approach. In the present work real part of the nucleus-nucleus interaction is microscopically calculated using equivalence relation between RGM and GCM

  18. Neutron scattering studies of a dilute magnetic semiconductor: Cd1-xMnxTe

    DEFF Research Database (Denmark)

    Steigenberger, Ursula; Lebech, Bente; Galazka, Robert R.

    1986-01-01

    The development of the magnetic ordering in the magnetic semiconductor Cd1-xMnxTe was investigated by elastic neutron scattering. A detailed study of the correlation length and the intensity as a function of temperature, direction in reciprocal space and concentration of the magnetic ions has been...

  19. Application of laser resonance scattering to the study of high-temperature plasma-wall interaction

    International Nuclear Information System (INIS)

    Maeda, Mitsuo; Muraoka, Katsunori; Hamamoto, Makoto; Akazaki, Masanori; Miyazoe, Yasushi

    1981-01-01

    Studies on laser resonance scattering and its application to the study of high-temperature plasma-wall interaction are reviewed. The application of dye laser beam to resonant scattering method has been developed. This method is able to detect low density atoms. The fluorescent photon counts can be estimated for a two-level system and a three-level system. The S/N ratio, Which is in close connection with the detection limit, has been estimated. The doppler effect due to the thermal motion of atoms is taken into consideration. The calibration of the absolute number of atoms is necessary. Tunable coherent light is used as the light source for resonance scattering method. This is able to excite atoms strongly and to increase the detection efficiency. As dye lasers, a N 2 laser, a YAG laser, and a KrF excimer laser have been studied. In VUV region, rare gas or rare gas halide lasers can be used. The strong output power can be expected when the resonance lines of atoms meet the synchronizing region of the excimer laser. The resonance scattering method is applied to the detection of impurity metal atoms in plasma. The studies of laser systems for the detection of hydrogen atoms are also in progress. (Kato, T.)

  20. Optical potential study of positron scattering by hydrogenic-type atoms

    International Nuclear Information System (INIS)

    Kuru Ratnavelu; Nithyanandan Natchimuthu; Kalai Kumar Rajgopal

    1999-01-01

    An optical potential method based on the close-coupling formalism has been implemented to study positron scattering by hydrogenic-type atoms. The present work will be reviewed in the context of other theories. Preliminary results will be presented and compared with experimental results. (author)

  1. Study of radiative corrections with application to the electron-neutrino scattering

    International Nuclear Information System (INIS)

    Oliveira, L.C.S. de.

    1977-01-01

    The radiative correction method is studied which appears in Quantum Field Theory, for some weak interaction processes. e.g., Beta decay and muon decay. Such a method is then applied to calculate transition probability for the electron-neutrino scattering using the U-A theory as a base. The calculations of infrared and ultraviolet divergences are also discussed. (L.C.) [pt

  2. Computational study of scattering of a zero-order Bessel beam by large nonspherical homogeneous particles with the multilevel fast multipole algorithm

    Science.gov (United States)

    Yang, Minglin; Wu, Yueqian; Sheng, Xinqing; Ren, Kuan Fang

    2017-12-01

    Computation of scattering of shaped beams by large nonspherical particles is a challenge in both optics and electromagnetics domains since it concerns many research fields. In this paper, we report our new progress in the numerical computation of the scattering diagrams. Our algorithm permits to calculate the scattering of a particle of size as large as 110 wavelengths or 700 in size parameter. The particle can be transparent or absorbing of arbitrary shape, smooth or with a sharp surface, such as the Chebyshev particles or ice crystals. To illustrate the capacity of the algorithm, a zero order Bessel beam is taken as the incident beam, and the scattering of ellipsoidal particles and Chebyshev particles are taken as examples. Some special phenomena have been revealed and examined. The scattering problem is formulated with the combined tangential formulation and solved iteratively with the aid of the multilevel fast multipole algorithm, which is well parallelized with the message passing interface on the distributed memory computer platform using the hybrid partitioning strategy. The numerical predictions are compared with the results of the rigorous method for a spherical particle to validate the accuracy of the approach. The scattering diagrams of large ellipsoidal particles with various parameters are examined. The effect of aspect ratios, as well as half-cone angle of the incident zero-order Bessel beam and the off-axis distance on scattered intensity, is studied. Scattering by asymmetry Chebyshev particle with size parameter larger than 700 is also given to show the capability of the method for computing scattering by arbitrary shaped particles.

  3. Anomalous thermodynamic behaviour of novel compounds: inelastic neutron scattering and lattice dynamics studies

    International Nuclear Information System (INIS)

    Mittal, R.

    2014-01-01

    The understanding of the thermodynamic properties of solids has important applications in diverse areas like condensed matter physics, materials science, mineralogy, geophysics, etc. We have been extensively investigating anomalous thermodynamic properties of compounds using the techniques of inelastic neutron scattering and lattice dynamics. We would present some of the results from our recent studies. Studies of materials exhibiting anomalous thermal expansion are of interest due to their fundamental scientific importance and potential applications in ceramic, optical and electronic industry etc. We have studied the thermodynamic properties of negative thermal expansion (NTE) compounds ZrW 2 O 8 , HfW 2 O 8 , ZrMo 2 O 8 , ZrV 2 O 7 , HfV 2 O 7 , Zn(CN) 2 , Cu 2 O, Ag 2 O, Ag 3 Co(CN) 6 and Ag 3 Fe(CN) 6 . Our calculations predicted that large softening of the phonon spectrum involving librational and translational modes below 10 MeV would be responsible for anomalous thermal expansion behaviour. High pressure inelastic neutron scattering experiments carried by us on cubic ZrW 2 O 8 , ZrMo 2 O 8 and Zn(CN) 2 confirmed the phonon softening. Our studies indicate that unusual phonon softening of low energy modes is able to account for the thermal expansion behaviour in these compounds. Superionic conduction in fluorite-structured (anti-fluorite, Li 2 O) oxides (MO 2 , M= U, Th) have applications in energy storage, conversion and nuclear industry. The possible role of phonon in initiation of diffusion has been studied in Li 2 O. We found that in the superionic regime lithium atoms may exhibit macroscopic movement along (100) direction. The microscopic modeling or simulation is found to play a pivotal role in understanding the conduction processes at high temperatures in Li 2 O. We have also studied zircon structured compounds MSiO 4 (M=Zr, Hf, Th, U), RPO 4 , (R=rare earth atom). The compounds are known to transform to the scheelite (body centered tetragonal, I4 1 /a

  4. A diffuse neutron scattering study of clustering in copper-nickel alloys

    International Nuclear Information System (INIS)

    Vrijen, J.

    1977-01-01

    The amount of clustering in Cu-Ni alloys in thermal equilibrium at several temperatures between 400degC and 700degC and ranging in composition between 20 and 80 atomic percent Ni has been determined by means of diffuse neutron scattering. A rough calculation of the excess elastic energy due to alloying Cu with Ni shows that the contribution of size effects to the configurational energy is asymmetric in the composition with its maximum located between 60 and 70 atomic percent Ni. This asymmetry is caused by different elastic constants for Cu and Ni and it might explain part of the asymmetry of clustering in Cu-Ni and its temperature dependence. With the help of the measured cluster parameters, the magnetic diffuse neutron scattering cross-sections of several differently clustered compositions in Cu-Ni could be interpreted, both well inside the ferromagnetic phase and in the transition region between ferromagnetism and superparamagnetism. Giants moments have been observed. Non-equilibrium distributions and their changes during relaxing towards equilibrium have been investigated by measuring the time-evolution of the diffuse scattering. The relaxation of the null matrix (composition without Bragg reflections for neutron scattering) has been measured at five temperatures between 320degC and 450degC. The results of these relaxations were compared with a few available kinetic models

  5. Ion-reversibility studies in amorphous solids using the two-atom scattering model

    International Nuclear Information System (INIS)

    Oen, O.S.

    1981-06-01

    An analytical two-atom scattering model has been developed to treat the recent discovery of the enhancement near 180 0 of Rutherford backscattering yields from disordered solids. In contrast to conventional calculations of Rutherford backscattering that treat scattering from a single atom only (the backscattering atom), the present model includes the interaction of a second atom lying between the target surface and the backscattering plane. The projectile ion makes a glancing collision with this second atom both before and after it is backscattered. The model predicts an enhancement effect whose physical origin arises from the tolerance of path for those ions whose inward and outward trajectories lie in the vicinity of the critical impact parameter. Results using Moliere scattering show how the yield enhancement depends on ion energy, backscattering depth, exit angle, scattering potential, atomic numbers of the projectile and target, and target density. In the model the critical impact parameter and critical angle play important roles. It is shown that these quantities depend on a single dimensionless parameter and analytical expressions for them are given which are accurate to better than 1%

  6. Small angle neutron scattering (SANS) study of gastric mucin solutions

    Science.gov (United States)

    Hong, Z.; Bansil, R.; Waigh, T.; Turner, B.; Bhaskar, K. R.; Afdhal, N.; Lal, J.

    2002-03-01

    We report the first results from a SANS study of purified porcine gastric mucin solutions in D2O. The ability of this glycoprotein to protect the stomach epithelium from acid damage, may be due to a pH dependent conformational transition which leads to gelation at low pH Cao et. al. (Biophysical. J. 76, 1250, 1999). SANS measurements were made over the concentration range of 1 -15 mg/ml at pH 7, 4 and 2. The data indicate that at pH 7 the excluded volume exponent is 1.7, characteristic of swollen chains whereas at pH 2 this exponent increases to 2, indicating theta or poor solvent conditions, consistent with the hydrophobic interactions increasing at lower pH. From a Guinier analysis of the 1mg/ml data at low q's (0.003- 0.007 Å-1) we estimate the cross section radius of the effective cylinder to be 23nm and its length as 96nm in an unbuffered sample, i.e. close to pH 7. In the intermediate q-range (0.01 -0.1Å-1) at pH 7 a fit to the Debye chain gives radius of gyration Rg of 16nm. Mucin is best modelled as an elongated micelle with a cylindrical or worm-like chain to represent the protein core and the sugar chains forming the corona. Results of such calculations will be presented.

  7. Main Achievements 2003-2004 - Condensed Matter Studies - Electronic structure of disordered alloys studied by Compton scattering

    International Nuclear Information System (INIS)

    2005-01-01

    3D momentum density and the Fermi surface of disordered Cu 0.86 Al 0.16 alloy were reconstructed from high-resolution Compton profiles. The effect known as ''nesting'' of the Fermi surface was revealed (cooperation with KEK, Tsukuba, Japan). This feature of the Fermi surface, when present, is believed to lead to local ordering phenomena in disordered systems. Our electron diffraction studies showed that a short-range order was indeed present in the alloy. Moreover, the character of the diffuse scattering (the four-fold splitting of the diffuse spots) pointed to the ''nesting'' of the Fermi surface as the origin of this ordering. The results lend support to the notion that the formation of the short-range order in nondiluted, disordered alloys can be driven by their electronic properties like the shape of the Fermi surface

  8. Theoretical study of elastic electron scattering off stable and exotic nuclei

    International Nuclear Information System (INIS)

    Roca-Maza, X.; Centelles, M.; Salvat, F.; Vinas, X.

    2008-01-01

    Results for elastic electron scattering by nuclei, calculated with charge densities of Skyrme forces and covariant effective Lagrangians that accurately describe nuclear ground states, are compared against experiment in stable isotopes. Dirac partial-wave calculations are performed with an adapted version of the ELSEPA package. Motivated by the fact that studies of electron scattering off exotic nuclei are intended in future facilities in the commissioned GSI and RIKEN upgrades, we survey the theoretical predictions from neutron-deficient to neutron-rich isotopes in the tin and calcium isotopic chains. The charge densities of a covariant interaction that describes the low-energy electromagnetic structure of the nucleon within the Lagrangian of the theory are used to this end. The study is restricted to medium- and heavy-mass nuclei because the charge densities are computed in mean-field approach. Because the experimental analysis of scattering data commonly involves parameterized charge densities, as a surrogate exercise for the yet unexplored exotic nuclei, we fit our calculated mean-field densities with Helm model distributions. This procedure turns out to be helpful to study the neutron-number variation of the scattering observables and allows us to identify correlations of potential interest among some of these observables within the isotopic chains

  9. Small angle scattering methods to study porous materials under high uniaxial strain

    Energy Technology Data Exchange (ETDEWEB)

    Le Floch, Sylvie, E-mail: sylvie.le-floch@univ-lyon1.fr; Balima, Félix; Pischedda, Vittoria; Legrand, Franck; San-Miguel, Alfonso [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France)

    2015-02-15

    We developed a high pressure cell for the in situ study of the porosity of solids under high uniaxial strain using neutron small angle scattering. The cell comprises a hydraulically actioned piston and a main body equipped with two single-crystal sapphire windows allowing for the neutron scattering of the sample. The sample cavity is designed to allow for a large volume variation as expected when compressing highly porous materials. We also implemented a loading protocol to adapt an existing diamond anvil cell for the study of porous materials by X-ray small angle scattering under high pressure. The two techniques are complementary as the radiation beam and the applied pressure are in one case perpendicular to each other (neutron cell) and in the other case parallel (X-ray cell). We will illustrate the use of these two techniques in the study of lamellar porous systems up to a maximum pressure of 0.1 GPa and 0.3 GPa for the neutron and X-ray cells, respectively. These devices allow obtaining information on the evolution of porosity with pressure in the pore dimension subdomain defined by the wave-numbers explored in the scattering process. The evolution with the applied load of such parameters as the fractal dimension of the pore-matrix interface or the apparent specific surface in expanded graphite and in expanded vermiculite is used to illustrate the use of the high pressure cells.

  10. High-resolution x-ray scattering studies of charge ordering in highly correlated electron systems

    International Nuclear Information System (INIS)

    Ghazi, M.E.

    2002-01-01

    Many important properties of transition metal oxides such as, copper oxide high-temperature superconductivity and colossal magnetoresistance (CMR) in manganites are due to strong electron-electron interactions, and hence these systems are called highly correlated systems. These materials are characterised by the coexistence of different kinds of order, including charge, orbital, and magnetic moment. This thesis contains high-resolution X-ray scattering studies of charge ordering in such systems namely the high-T C copper oxides isostructural system, La 2-x Sr x NiO 4 with various Sr concentrations (x = 0.33 - 0.2), and the CMR manganite system, Nd 1/2 Sr 1/2 MnO 3 . It also includes a review of charge ordering in a large variety of transition metal oxides, such as ferrates, vanadates, cobaltates, nickelates, manganites, and cuprates systems, which have been reported to date in the scientific literature. Using high-resolution synchrotron X-ray scattering, it has been demonstrated that the charge stripes exist in a series of single crystals of La 2-x Sr x NiO 4 with Sr concentrations (x = 0.33 - 0.2) at low temperatures. Satellite reflections due to the charge ordering were found with the wavevector (2ε, 0, 1) below the charge ordering transition temperature, T CO , where 2ε is the amount of separation from the corresponding Bragg peak. The charge stripes are shown to be two-dimensional in nature both by measurements of their correlation lengths and by measurement of the critical exponents of the charge stripe melting transition with an anomaly at x = 0.25. The results show by decreasing the hole concentration from the x = 0.33 to 0.2, the well-correlated charge stripes change to a glassy state at x = 0.25. The electronic transition into the charge stripe phase is second-order without any corresponding structural transition. Above the second-order transition critical scattering was observed due to fluctuations into the charge stripe phase. In a single-crystal of Nd

  11. Study of the scattering of the light in aqueous samples collagen in the presence of nanoparticles and curcuma pigment

    Science.gov (United States)

    Silva, F. M. L.; Alencar, L. D. S.; Bernardi, M. I. B.; Lima, F. W. S.; Melo, C. A. S.

    2015-06-01

    In this work we investigate the scattering of light in means turbid in the presence or not of pigment and nanoparticles. For this we initially using a sample of collagen from means turbid with and without the presence of curcuma pigments and nanoparticles. Our results show that the light scattering is more intense in the samples with nanoparticles and curcuma pigment.

  12. A Microbeam Small-Angle X-ray Scattering Study on Enamel Crystallites in Subsurface Lesion

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, N; Ohta, N; Matsuo, T [Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan); Tanaka, T; Terada, Y; Kamasaka, H; Kometani, T, E-mail: yagi@spring8.or.j [Ezaki Glico Co. Ltd., 4-6-5 Utajima, Nishiyodogawa-ku, Osaka 555-8502 (Japan)

    2010-10-01

    The early caries lesion in bovine tooth enamel was studied by two different X-ray diffraction systems at the SPring-8 third generation synchrotron radiation facility. Both allowed us simultaneous measurement of the small and large angle regions. The beam size was 6{mu}m at BL40XU and 50{mu}m at BL45XU. The small-angle scattering from voids in the hydroxyapatite crystallites and the wide-angle diffraction from the hydroxyapatite crystals were observed simultaneously. At BL40XU an X-ray image intensifier was used for the small-angle and a CMOS flatpanel detector for the large-angle region. At BL45XU, a large-area CCD detector was used to cover both regions. A linear microbeam scan at BL40XU showed a detailed distribution of voids and crystals and made it possible to examine the structural details in the lesion. The two-dimensional scan at BL45XU showed distribution of voids and crystals in a wider region in the enamel. The simultaneous small- and wide-angle measurement with a microbeam is a powerful tool to elucidate the mechanisms of demineralization and remineralization in the early caries lesion.

  13. A Microbeam Small-Angle X-ray Scattering Study on Enamel Crystallites in Subsurface Lesion

    International Nuclear Information System (INIS)

    Yagi, N; Ohta, N; Matsuo, T; Tanaka, T; Terada, Y; Kamasaka, H; Kometani, T

    2010-01-01

    The early caries lesion in bovine tooth enamel was studied by two different X-ray diffraction systems at the SPring-8 third generation synchrotron radiation facility. Both allowed us simultaneous measurement of the small and large angle regions. The beam size was 6μm at BL40XU and 50μm at BL45XU. The small-angle scattering from voids in the hydroxyapatite crystallites and the wide-angle diffraction from the hydroxyapatite crystals were observed simultaneously. At BL40XU an X-ray image intensifier was used for the small-angle and a CMOS flatpanel detector for the large-angle region. At BL45XU, a large-area CCD detector was used to cover both regions. A linear microbeam scan at BL40XU showed a detailed distribution of voids and crystals and made it possible to examine the structural details in the lesion. The two-dimensional scan at BL45XU showed distribution of voids and crystals in a wider region in the enamel. The simultaneous small- and wide-angle measurement with a microbeam is a powerful tool to elucidate the mechanisms of demineralization and remineralization in the early caries lesion.

  14. Inelastic and quasielastic neutron scattering studies on soft matter and biomolecules

    International Nuclear Information System (INIS)

    Kanaya, Toshiji

    2015-01-01

    Some characteristic features of soft matter and biomolecules in the inelastic and quasielastic neutron scattering (INS and QENS) studies are described. In order to clarify the current situation of the studies the research history on soft matter and biomolecules by INS and QENS are described. As examples of the studies of slow dynamics of soft matter, neutron spin echo studies on breathing mode of polymer micelle and static and dynamics fluctuations in polymer gels. (author)

  15. Porosity of the Marcellus Shale: A contrast matching small-angle neutron scattering study

    Science.gov (United States)

    Bahadur, Jitendra; Ruppert, Leslie F.; Pipich, Vitaliy; Sakurovs, Richard; Melnichenko, Yuri B.

    2018-01-01

    Neutron scattering techniques were used to determine the effect of mineral matter on the accessibility of water and toluene to pores in the Devonian Marcellus Shale. Three Marcellus Shale samples, representing quartz-rich, clay-rich, and carbonate-rich facies, were examined using contrast matching small-angle neutron scattering (CM-SANS) at ambient pressure and temperature. Contrast matching compositions of H2O, D2O and toluene, deuterated toluene were used to probe open and closed pores of these three shale samples. Results show that although the mean pore radius was approximately the same for all three samples, the fractal dimension of the quartz-rich sample was higher than for the clay-rich and carbonate-rich samples, indicating different pore size distributions among the samples. The number density of pores was highest in the clay-rich sample and lowest in the quartz-rich sample. Contrast matching with water and toluene mixtures shows that the accessibility of pores to water and toluene also varied among the samples. In general, water accessed approximately 70–80% of the larger pores (>80 nm radius) in all three samples. At smaller pore sizes (~5–80 nm radius), the fraction of accessible pores decreases. The lowest accessibility to both fluids is at pore throat size of ~25 nm radii with the quartz-rich sample exhibiting lower accessibility than the clay- and carbonate-rich samples. The mechanism for this behaviour is unclear, but because the mineralogy of the three samples varies, it is likely that the inaccessible pores in this size range are associated with organics and not a specific mineral within the samples. At even smaller pore sizes (~generally follows that of water; however, in the smallest pores (~<2.5 nm radius), accessibility to toluene decreases, especially in the clay-rich sample which contains about 30% more closed pores than the quartz- and carbonate-rich samples. Results from this study show that mineralogy of producing intervals

  16. A multicenter study of using carbon nanoparticles to show sentinel lymph nodes in early gastric cancer.

    Science.gov (United States)

    Yan, Jun; Zheng, Xiaoling; Liu, Zhangyuanzhu; Yu, Jiang; Deng, Zhenwei; Xue, Fangqing; Zheng, Yu; Chen, Feng; Shi, Hong; Chen, Gang; Lu, Jianping; Cai, Lisheng; Cai, Mingzhi; Xiang, Gao; Hong, Yunfeng; Chen, Wenbo; Li, Guoxin

    2016-04-01

    Lymph node metastasis occurs in approximately 10% of early gastric cancer. Preoperative or intra-operative identification of lymph node metastasis in early gastric cancer is crucial for surgical planning. The purpose of this study was to evaluate the feasibility of using carbon nanoparticles to show sentinel lymph nodes (SLNs) in early gastric cancer. A multicenter study was performed between July 2012 and November 2014. Ninety-one patients with early gastric cancer identified by preoperative endoscopic ultrasonography were recruited. One milliliter carbon nanoparticles suspension, which is approved by Chinese Food and Drug Administration, was endoscopically injected into the submucosal layer at four points around the site of the primary tumor 6-12 h before surgery. Laparoscopic radical resection with D2 lymphadenectomy was performed. SLNs were defined as nodes that were black-dyed by carbon nanoparticles in greater omentum and lesser omentum near gastric cancer. Lymph node status and SLNs accuracy were confirmed by pathological analysis. All patients had black-dyed SLNs lying in greater omentum and/or lesser omentum. SLNs were easily found under laparoscopy. The mean number of SLNs was 4 (range 1-9). Carbon nanoparticles were around cancer in specimen. After pathological analysis, 10 patients (10.99%) had lymph node metastasis in 91 patients with early gastric cancer. SLNs were positive in 9 cases and negative in 82 cases. In pathology, carbon nanoparticles were seen in lymphatic vessels, lymphoid sinus, and macrophages in SLNs. When SLNs were positive, cancer cells were seen in lymph nodes. The sensitivity, specificity, and accuracy of black-dyed SLNs in early gastric cancers were 90, 100, and 98.9 %, respectively. No patient had any side effects of carbon nanoparticles in this study. It is feasible to use carbon nanoparticles to show SLNs in early gastric cancer. Carbon nanoparticles suspension is safe for submucosal injection.

  17. A quasi-elastic neutron scattering and neutron spin-echo study of hydrogen bonded system

    Energy Technology Data Exchange (ETDEWEB)

    Branca, C.; Faraone, A.; Magazu, S.; Maisano, G.; Mangione, A

    2004-07-15

    This work reports neutron spin echo results on aqueous solutions of trehalose, a naturally occurring disaccharide of glucose, showing an extraordinary bioprotective effectiveness against dehydration and freezing. We collected data using the SPAN spectrometer (BENSC, Berlin) on trehalose aqueous solutions at different temperature values. The obtained findings are compared with quasi-elastic neutron scattering results in order to furnish new results on the dynamics of the trehalose/water system on the nano and picoseconds scale.

  18. Study of CuAl(100) by using He ion scattering

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, L; Zur Muhlen, E; O` Connor, D J [Newcastle Univ., NSW (Australia). Dept. of Physics

    1994-12-31

    The clean CuAl (100) surface has been investigated by using He{sup +} ion scattering. The polar scans show that Al atoms randomly replace the Cu atoms but sit (0.15{+-}0.05) Angstroms higher than the Cu atoms. The outmost layer concentration of Al is about (17{+-}3)%. The aluminium concentration on the outmost layer is sensitive to the sample temperature up to 300 deg C. 7 refs., 5 figs.

  19. Study of CuAl(100) by using He ion scattering

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, L.; Zur Muhlen, E.; O`Connor, D.J. [Newcastle Univ., NSW (Australia). Dept. of Physics

    1993-12-31

    The clean CuAl (100) surface has been investigated by using He{sup +} ion scattering. The polar scans show that Al atoms randomly replace the Cu atoms but sit (0.15{+-}0.05) Angstroms higher than the Cu atoms. The outmost layer concentration of Al is about (17{+-}3)%. The aluminium concentration on the outmost layer is sensitive to the sample temperature up to 300 deg C. 7 refs., 5 figs.

  20. A critical scattering study of the helical antiferromagnets Ho and Dy

    International Nuclear Information System (INIS)

    Gaulin, B.D.; Hagen, M.; Child, H.R.

    1988-01-01

    We have measured the frequency integrated magnetic critical scattering of neutrons from paramagnetic Dy and Ho. Analysis of these data show the paramagnetic to helical antiferromagnetic phase transitions are characterized by the critical exponents ν = 0.57 +- 0.05 and γ = 1.05 = +- .07 for Dy and ν = 0.57 +- .04 and γ = 1.14 = +- .10 for Ho. 3 refs., 2 figs., 1 tab

  1. Rayleigh light scattering in fullerene covered by a spherical argon film - a molecular dynamics study

    CERN Document Server

    Dawid, A

    2003-01-01

    We have calculated (by a molecular dynamics method) the interaction-induced polarizability correlation functions and spectra of the depolarized light scattering from fullerene C sub 6 sub 0 molecules surrounded by an argon 'atmosphere' (layer). The calculated correlation functions and spectra of (C sub 6 sub 0)Ar sub n (n = 32, 40, 46) clusters show a substantial dependence on the number n of atoms in the layer.

  2. Low-energy electron scattering from CO. 2: Ab-initio study using the frame-transformation theory

    Science.gov (United States)

    Chandra, N.

    1976-01-01

    The Wigner-Eisenbud R matrix method has been combined with the frame transformation theory to study electron scattering from molecular systems. The R matrix, calculated at the boundary point of the molecular core radius, has been transformed to the space frame in order to continue the solution of the scattering equations in the outer region where rotational motion of the nuclei is taken into account. This procedure has been applied to a model calculation of thermal energy electron scattering from CO.

  3. Fast electron and X-ray scattering as a tool to study target's structure

    Energy Technology Data Exchange (ETDEWEB)

    Amusia, M.Ya. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); A.F. Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation)], E-mail: amusia@vms.huji.ac.il

    2007-06-15

    We concentrate on several relatively new aspects of the study of fast electron and X-ray scattering by atoms and atom-like objects, namely endohedral atoms and fullerenes. However, main attention is given to fast charge particle scattering. We show that the corresponding cross-sections, being expressed via so-called generalized oscillator strengths (GOS), give information on the electronic structure of the target and on the role of electron correlations in it. We consider what sort of information became available when analyzing the dependence of GOS upon their multipolarity, transferred momentum q and energy {omega}. To obtain theoretical results, we employ both the one-electron Hartree-Fock approximation and account for the multi-electron correlation in the target, using the random phase approximation with exchange. We demonstrate the role of non-dipole corrections in the small-angle fast-electron inelastic scattering. There dipole contribution dominates while non-dipole corrections can be considerably and controllably enhanced as compared to the case of low and medium energy photoionization. We show also that analyses of GOS for discrete level excitations permit to clarify their multipolarity. The results of calculations of Compton excitation and ionization cross-sections are presented. Attention is given to cooperative effects in inelastic fast electron-atom scattering that results in directed motion of the secondary electrons, a phenomenon that is similar to 'drag currents' in photoionization. We demonstrate how one should derive GOS for endohedral atoms, e.g. A-C{sub 60} and what is the additional information that can be obtained from corresponding GOS. Most of discussions are illustrated by the results of concrete calculations.

  4. Identification of delamination interface in composite laminates using scattering characteristics of lamb wave: numerical and experimental studies

    Science.gov (United States)

    Singh, Rakesh Kumar; Ramadas, C.; Balachandra Shetty, P.; Satyanarayana, K. G.

    2017-04-01

    Considering the superior strength properties of polymer based composites over metallic materials, they are being used in primary structures of aircrafts. However, these polymeric materials are much more complex in behaviour due to their structural anisotropy along with existence of different materials unlike in metallic alloys. These pose challenge in flaw detection, residual strength determination and life of a structure with their high susceptibility to impact damage in the form of delaminations/disbonds or cracks. This reduces load-bearing capability and potentially leads to structural failure. With this background, this study presents a method to identify location of delamination interface along thickness of a laminate. Both numerical and experimental studies have been carried out with a view to identify the defect, on propagation, mode conversion and scattering characteristics of fundamental anti-symmetric Lamb mode (Ao) when it passed through a semi-infinite delamination. Further, the reflection and transmission scattering coefficients based on power and amplitude ratios of the scattered waves have been computed. The methodology was applied on numerically simulated delaminations to illustrate the efficacy of the method. Results showed that it could successfully identify delamination interface.

  5. Study on the relationship between PM2.5 concentration and visibility in Beijing based on light scattering theory

    Science.gov (United States)

    Yang, YuFeng; Li, Ting

    2018-02-01

    The study of the relationship between transmittance visibility and PM2.5 concentration under the haze conditions has important theoretical significance for Free Space Optical communication (FSO). In this paper, the influence of PM2.5 concentration on the transmittance, attenuation coefficient and visibility was studied by light scattering theory, and the results by Mie theory and Monte Carlo method were analyzed. At the same time, the effect of PM2.5 particle size distribution on visibility was also analyzed, and the visibility calculated by light scattering method was compared with the visibility measured in Beijing from 2014 to 2016. The result shows that the higher PM2.5 concentration is the more obvious the multiple scattering effect is. When the mass concentration of PM2.5 is constant, the larger the geometric mean of the particle diameter is, the larger the visibility is. By comparing the visibility measured and the visibility calculated, we can see that when PM2.5 concentration is higher than 100μg/m3 , PM2.5 is the main factor affecting the visibility; and when PM2.5 concentration is lower than 100μg/m3, other factors (such as PM10, wind speed, air pressure and gas molecules) should also need to be considered.

  6. Study of the relative humidity dependence of aerosol light-scattering in southern Spain

    Directory of Open Access Journals (Sweden)

    Gloria Titos

    2014-09-01

    Full Text Available This investigation focuses on the characterisation of the aerosol particle hygroscopicity. Aerosol particle optical properties were measured at Granada, Spain, during winter and spring seasons in 2013. Measured optical properties included particle light-absorption coefficient (σap and particle light-scattering coefficient (σsp at dry conditions and at relative humidity (RH of 85±10%. The scattering enhancement factor, f(RH=85%, had a mean value of 1.5±0.2 and 1.6±0.3 for winter and spring campaigns, respectively. Cases of high scattering enhancement were more frequent during the spring campaign with 27% of the f(RH=85% values above 1.8, while during the winter campaign only 8% of the data were above 1.8. A Saharan dust event (SDE, which occurred during the spring campaign, was characterised by a predominance of large particles with low hygroscopicity. For the day when the SDE was more intense, a mean daily value of f(RH=85%=1.3±0.2 was calculated. f(RH=85% diurnal cycle showed two minima during the morning and afternoon traffic rush hours due to the increase in non-hygroscopic particles such as black carbon and road dust. This was confirmed by small values of the single-scattering albedo and the scattering Ångstrom exponent. A significant correlation between f(RH=85% and the fraction of particulate organic matter and sulphate was obtained. Finally, the impact of ambient RH in the aerosol radiative forcing was found to be very small due to the low ambient RH. For high RH values, the hygroscopic effect should be taken into account since the aerosol forcing efficiency changed from −13 W/m2 at dry conditions to −17 W/m2 at RH=85%.

  7. Nuclear scattering studies by the scattering of medium-energy electrons. Progress report, January 1, 1977--October 31, 1977

    International Nuclear Information System (INIS)

    Peterson, G.A.

    1977-10-01

    Tune-up experiments were carried out at the Bates Linear Accelerator of Middleton, Massachusetts, on the 180 0 electron scattering apparatus designed and constructed by the University of Massachusetts under contract E(11-1)-2545. This apparatus serves as adjunct equipment to the Bates dispersion-matching spectrometer. Form factors were measured for the low-lying states of 27 Al over the momentum transfer range from 0.7 to 2.6 fm -1 . A paper was published in the Physical Review on low-momentum transfer elastic electron scattering from 3 He. The 3 He rms radius was determined to be 1.89 +- 0.05 fm from measurements made at the National Bureau of Standards over the momentum transfer range-squared between 0.032 and 0.34 fm -2 . A Physical Review paper was published in November, 1977, on the results of elastic electron scattering from 25 Mg over the momentum transfer range from 0.19 to 2.56 fm -1 at both forward and backward angles. Values of all of the ground-state multipole moments of both Coulomb and magnetic character were obtained. A paper was submitted for publication on the electroexcitation of giant dipole and quadrupole resonances in 20 Ne. Electric dipole and quadrupole strength was found throughout the region from 12.5 through 25 MeV. About 65% and 100% of the energy-weighted dipole and quadrupole sum rules, respectively, were exhausted. A preliminary run was made on 42 Ca and 44 Ca at the National Bureau of Standards for an incident electron energy of 54.3 MeV and a 145 0 scattering angle in an attempt to observe f/sub 7 / 2 / to f/sub 5 / 2 / magnetic dipole transitions. A paper was composed on the 160 0 inelastic scattering of electrons from 58 Ni at momentum transfers near 2 fm -1 . Strong M8 transitions were observed which are characterized by predominantly one particle--one hole excitations characterized by the configuration

  8. X-ray and neutron scattering studies of complex confined fluids

    International Nuclear Information System (INIS)

    Sinha, S. K.

    1999-01-01

    We review recent X-ray and neutron scattering studies of the structure and dynamics of confined complex fluids. This includes the study of polymer conformations and binary fluid phase transitions in porous media using Small Angle Neutron scattering, and the use of synchrotrons radiation to study ordering and fluctuation phenomena at solid/liquid and liquid/air interfaces. Ordering of liquids near a solid surface or in confinement will be discussed, and the study, via specular and off-specular X-ray reflectivity, of capillary wave fluctuations on liquid polymer films. Finally, we shall discuss the use of high-brilliance beams from X-ray synchrotrons to study via photon correlation spectroscopy the slow dynamics of soft condensed matter systems

  9. Material rhetoric: spreading stones and showing bones in the study of prehistory.

    Science.gov (United States)

    Van Reybrouck, David; de Bont, Raf; Rock, Jan

    2009-06-01

    Since the linguistic turn, the role of rhetoric in the circulation and the popular representation of knowledge has been widely accepted in science studies. This article aims to analyze not a textual form of scientific rhetoric, but the crucial role of materiality in scientific debates. It introduces the concept of material rhetoric to understand the promotional regimes in which material objects play an essential argumentative role. It analyzes the phenomenon by looking at two students of prehistory from nineteenth-century Belgium. In the study of human prehistory and evolution, material data are either fairly abundant stone tools or very scarce fossil bones. These two types of material data stand for two different strategies in material rhetoric. In this article, the first strategy is exemplified by Aimé Rutot, who gathered great masses of eoliths (crudely chipped stones which he believed to be prehistoric tools). The second strategy is typified by the example of Julien Fraipont, who based his scientific career on only two Neanderthal skeletons. Rutot sent his "artifacts" to a very wide audience, while Fraipont showed his skeletons to only a few selected scholars. Unlike Rutot, however, Fraipont was able to monitor his audience's interpretation of the finds by means of personal contacts. What an archaeologist gains in reach, he or she apparently loses in control. In this article we argue that only those scholars who find the right balance between the extremes of reach and control will prove to be successful.

  10. Ribosomal studies on the 70S ribosome of E.coli by means of neutron scattering

    International Nuclear Information System (INIS)

    Burkhardt, N.

    1997-01-01

    Ribosomes are ribonucleo-protein complexes, which catalyse proteinbiosynthesis in all living organisms. Currently, most of the structural models of the prokaryotic 70S ribosome rely on electron microscopy and describe mainly the outer shape of the particle. Neutron scattering can provide information on the internal structure of the ribosome. Parts of the structure can be contrasted for neutrons by means of an isotopic exchange of the naturally occurring hydrogen ( 1 H) for deuterium ( 2 H), allowing direct measurements in situ. Specifically deuterium-labeled ribosomes (E. coli) were prepared and analysed with neutron scattering. The biochemical methods were established and combined to a generally applicable preparation system. This allows labeling of all ribosomal components in any combination. A systematic analysis of the protein and RNA phases resulted in the development of a new model for the 70S ribosome. This model describes not only the outer shape of the particle, but displays also an experimentally determined internal protein-RNA distribution and the border of subunits for the first time (four-phase model; resolution: 50A). Models of the 70S ribosome from other studies were evaluated and ranked according to consistency with the measured scattering data. Applying a new neutron scattering technique of particular sensitivity, the proton-spin contrast-variation, single proteins could be measured and localized. The positions of the proteins S6 and S10 were determined, providing the first coordinates of protein mass centers within the 70S ribosome. (orig.) [de

  11. Study on the Interaction between Cadmium Sulphide Nanoparticles and Proteins by Resonance Rayleigh Scattering Spectra

    Directory of Open Access Journals (Sweden)

    Weiwei Zhu

    2013-01-01

    Full Text Available The interaction of cadmium sulphide nanoparticles [(CdSn] with proteins has been studied by resonance Rayleigh scattering spectra (RRS. Below the isoelectric point, proteins such as bovine serum albumin (BSA, human serum albumin (HSA, lysozyme (Lys, hemoglobin (HGB, and ovalbumin (OVA can bind with CdSn to form macromolecules by virtue of electrostatic attraction and hydrophobic force. It can result in the enhancement of resonance Rayleigh scattering spectra (RRS intensity. Their maximum scattering peaks were 280 nm, and there was a smaller peak at 370 nm. The scattering enhancement (ΔIRRS is directly proportional to the concentration of proteins. A new RRS method for the determination of trace proteins using uncapped CdSn nanoparticles probe has been developed. The detection limits are 19.6 ng/mL for HSA, 16.7 ng/mL for BSA, 18.5 ng/mL for OVA, 80.2 ng/mL for HGB, and 67.4 ng/mL for Lys, separately. In this work, the optimum condition of reaction, the effect of foreign, and the analytical application had been investigated.

  12. Quantum mechanical studies of heavy ion scattering processes. Progress report, July 15, 1983-March, 1984

    International Nuclear Information System (INIS)

    Heil, T.G.

    1984-01-01

    The research done under this contract should provide valuable contributions to our understanding of atomic collision processes. The essence of this project is the description of low energy atomic collision process using molecular states formed by the collision partners in the interaction region. Over the eight months that this contract has been in effect, significant progress has been made on both fundamental and applied levels. On the most basic level, we have recently developed a new diabatic representation of the scattering which has none of the defects associated with the most commonly used formulation of Smith. This may prove to be of great importance since a proper diabatic description is thought to be a more reasonable representation of the actual physical scattering process than the adiabatic description. It should be noted that there is a great deal of controversy surrounding the word proper but our new formulation satisfies most, if not all, criteria for diabatic states. In addition, we have carried out or initiated theoretical studies on a number of atomic scattering processes involving charge transfer reactions and proton-induced fine-structure transitions. Our calculations of differential scattering cross sections for low energy charge transfer reaction should be of particular importance. A number of experimental groups are now proposing to measure these cross sections which our calculations predict should have large, striking features. Such comparisons would provide valuable tests of the theory of low energy atomic collision processes on a more fundamental level than previous comparisons of the total cross sections

  13. Neutron scattering. Lectures

    Energy Technology Data Exchange (ETDEWEB)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)

    2010-07-01

    The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

  14. Neutron scattering. Lectures

    International Nuclear Information System (INIS)

    Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner

    2010-01-01

    The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)

  15. Size-dependent endocytosis of gold nanoparticles studied by three-dimensional mapping of plasmonic scattering images

    Directory of Open Access Journals (Sweden)

    Lee Chia-Wei

    2010-12-01

    Full Text Available Abstract Background Understanding the endocytosis process of gold nanoparticles (AuNPs is important for the drug delivery and photodynamic therapy applications. The endocytosis in living cells is usually studied by fluorescent microscopy. The fluorescent labeling suffers from photobleaching. Besides, quantitative estimation of the cellular uptake is not easy. In this paper, the size-dependent endocytosis of AuNPs was investigated by using plasmonic scattering images without any labeling. Results The scattering images of AuNPs and the vesicles were mapped by using an optical sectioning microscopy with dark-field illumination. AuNPs have large optical scatterings at 550-600 nm wavelengths due to localized surface plasmon resonances. Using an enhanced contrast between yellow and blue CCD images, AuNPs can be well distinguished from cellular organelles. The tracking of AuNPs coated with aptamers for surface mucin glycoprotein shows that AuNPs attached to extracellular matrix and moved towards center of the cell. Most 75-nm-AuNPs moved to the top of cells, while many 45-nm-AuNPs entered cells through endocytosis and accumulated in endocytic vesicles. The amounts of cellular uptake decreased with the increase of particle size. Conclusions We quantitatively studied the endocytosis of AuNPs with different sizes in various cancer cells. The plasmonic scattering images confirm the size-dependent endocytosis of AuNPs. The 45-nm-AuNP is better for drug delivery due to its higher uptake rate. On the other hand, large AuNPs are immobilized on the cell membrane. They can be used to reconstruct the cell morphology.

  16. Elastic and inelastic proton-nucleus scattering at 156MeV: experimental study and analysis in impulse approximation

    International Nuclear Information System (INIS)

    Comparat, Vincent.

    1975-01-01

    In this work a high spatial resolution hodoscope is described. Scattered particles are detected in the image plane of a magnetic spectrometer by a proportional chamber with 96 wires of 1mm spacing. This hodoscope has been used for elastic and inelastic scattering experiments, of 156MeV protons, on 11 targets ranging from 12 C to 209 Bi. A phenomenological optical model calculation has been carried out to analyse the experimental elastic cross sections data. The dependance of the parameters as a function of the number of mass or the incident energy has been studied. The inelastic scattering results have been interpreted within the framework of the D.W.I.A. As the final results are dependant of the nucleon model, the optical potential parameters as well as the finite range approximation, several trials have been performed. Nevertheless, the DWIA seems to give about twice the experimental values for collective excitations in light or medium nuclei. The first order optical potential derived from the impulse approximation was calculated and the results compared to the experimental elastic cross sections. Several approximations were tested as non locality, off energy shell effects and the motion of the target nucleon. The usual approximation on these quantities are justified if the momentum transfer is less than 3fm -1 . The nucleon-nucleus transition matrix is obtained by solving the Lippmann-Schwinger equation, using the moment method. The first order optical potential derived from these calculations is not realistic. The intensity of the nucleon-nucleon transition is too important, and that explained the disagreement at low momentum transfers. This study shows that the multiple scattering expansion of the Lippmann-Schwinger equation, is not a good method to obtain the exact solution. It is better to do some approximations (i.e. of shell approximation) directly on the integral equation [fr

  17. Study of light scattering using C-Quant® in patients with Fuchs' endothelial dystrophy: A pilot study.

    Science.gov (United States)

    Castaño-Martín, B; Gros-Otero, J; Martínez, J; Teus, M

    2017-11-01

    The purpose of this study was to determine the light scattering in patients with Fuchs' endothelial dystrophy without clinically significant corneal oedema, and evaluate its relationship with endothelial cell count, corneal thickness, and corneal biomechanical parameters. The values of light scattering were measured by C-Quant ® (Oculus Optikgeräte GmbH, Germany) in 32 eyes of 17 patients diagnosed with Fuchs' endothelial dystrophy without clinically significant corneal oedema. Corneal biomechanical properties were determined using ORA (ocular response) and Corvis ST ® (tonometry). A light scattering value outside the normal range was observed in 93.8% of eyes studied. No statistically significant association (P>.05) was found between the values of the measured light scattering by C-Quant ® and endothelial count, pachymetry, or corneal biomechanical properties. In this study, changes were found in the values of light scattering values of patients with corneal Fuchs' endothelial dystrophy. This change does not appear to correlate significantly with disease severity. Copyright © 2017 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

  18. An experimental study of the scatter correction by using a beam-stop-array algorithm with digital breast tomosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ye-Seul; Park, Hye-Suk; Kim, Hee-Joung [Yonsei University, Wonju (Korea, Republic of); Choi, Young-Wook; Choi, Jae-Gu [Korea Electrotechnology Research Institute, Ansan (Korea, Republic of)

    2014-12-15

    Digital breast tomosynthesis (DBT) is a technique that was developed to overcome the limitations of conventional digital mammography by reconstructing slices through the breast from projections acquired at different angles. In developing and optimizing DBT, The x-ray scatter reduction technique remains a significant challenge due to projection geometry and radiation dose limitations. The most common approach to scatter reduction is a beam-stop-array (BSA) algorithm; however, this method raises concerns regarding the additional exposure involved in acquiring the scatter distribution. The compressed breast is roughly symmetric, and the scatter profiles from projections acquired at axially opposite angles are similar to mirror images. The purpose of this study was to apply the BSA algorithm with only two scans with a beam stop array, which estimates the scatter distribution with minimum additional exposure. The results of the scatter correction with angular interpolation were comparable to those of the scatter correction with all scatter distributions at each angle. The exposure increase was less than 13%. This study demonstrated the influence of the scatter correction obtained by using the BSA algorithm with minimum exposure, which indicates its potential for practical applications.

  19. X-ray and neutron small-angle scattering studies of human serum lipoproteins

    International Nuclear Information System (INIS)

    Luzzati, V.; Tardieu, A.; Mateu, L.; Sardet, C.; Stuhrmann, H.B.; Aggerbeck, L.; Scanu, A.M.

    1976-01-01

    The paper describes an extended x-ray study of two types of human serum lipoproteins and a neutron study of one of them. The results are similar and to some extent complementary. Serum lipoproteins provide an excellent illustration of the wealth of information that can be obtained by a small-angle scattering approach to the structure of particles with non-uniform density distribution, by using solvents of variable density

  20. X-ray scattering studies of non-equilibrium ordering processes

    International Nuclear Information System (INIS)

    Nagler, S.E.

    1992-01-01

    This report summarizes the major results obtained under US DOE Grant Number FG05-90ER45280 from the dates November 1, 1989 through October 31, 1992 inclusive. The principal work includes x-ray scattering studies of phase transition kinetics in binary alloy order-disorder transitions, block co-polymer crystallization, and charge density wave solids under applied electric fields, and studies of magnetic excitations in low dimensional quantum systems

  1. A review on the study of polymer properties by Small Angle Neutron Scattering

    International Nuclear Information System (INIS)

    Seong, Baek Seok; Lee, Chang Hee; Sim, Hae Seop; Lee, Jung Sool; Kim, Hong Doo; Kim, Eu Gene; Cha, Kuk Heon

    1998-05-01

    This report contains concept of small angle neutron scattering , various design features and considerations of the small angle neutron spectrometer at HANARO, and recent trends of polymer studies by using this SANS technique with the installation of the spectrometer in near future. We, therefore, wish to review feasibility of small angle studies for polymer field at this spectrometer and to help possible beam time users for their experimental consideration. (author). 23 refs., 7 tabs., 23 figs

  2. Enhanced Scattering of Diffuse Ions on Front of the Earth's Quasi-Parallel Bow Shock: a Case Study

    Science.gov (United States)

    Kis, A.; Matsukiyo, S.; Otsuka, F.; Hada, T.; Lemperger, I.; Dandouras, I. S.; Barta, V.; Facsko, G. I.

    2017-12-01

    In the analysis we present a case study of three energetic upstream ion events at the Earth's quasi-parallel bow shock based on multi-spacecraft data recorded by Cluster. The CIS-HIA instrument onboard Cluster provides partial energetic ion densities in 4 energy channels between 10 and 32 keV.The difference of the partial ion densities recorded by the individual spacecraft at various distances from the bow shock surface makes possible the determination of the spatial gradient of energetic ions.Using the gradient values we determined the spatial profile of the energetic ion partial densities as a function of distance from the bow shock and we calculated the e-folding distance and the diffusion coefficient for each event and each ion energy range. Results show that in two cases the scattering of diffuse ions takes place in a normal way, as "by the book", and the e-folding distance and diffusion coefficient values are comparable with previous results. On the other hand, in the third case the e-folding distance and the diffusion coefficient values are significantly lower, which suggests that in this case the scattering process -and therefore the diffusive shock acceleration (DSA) mechanism also- is much more efficient. Our analysis provides an explanation for this "enhanced" scattering process recorded in the third case.

  3. A cross-sectional study of Tritrichomonas foetus infection among healthy cats at shows in Norway

    Directory of Open Access Journals (Sweden)

    Nødtvedt Ane

    2011-06-01

    Full Text Available Abstract Background In recent years, the protozoan Tritrichomonas foetus has been recognised as an important cause of chronic large-bowel diarrhoea in purebred cats in many countries, including Norway. The aim of this cross-sectional study was to determine the proportion of animals with T. foetus infection among clinically healthy cats in Norway and to assess different risk factors for T. foetus infection, such as age, sex, former history of gastrointestinal symptoms and concurrent infections with Giardia duodenalis and Cryptosporidium sp. Methods The sample population consisted of 52 cats participating in three cat shows in Norway in 2009. Samples were examined for motile T. foetus by microscopy, after culturing and for T. foetus-DNA by species-specific nested PCR, as well as for Giardia cysts and Cryptosporidium oocysts by immunofluorescent antibody test (IFAT. Results By PCR, T. foetus-DNA was demonstrated in the faeces of 11 (21% of the 52 cats tested. DNA-sequencing of five positive samples yielded 100% identity with previous isolates of T. foetus from cats. Only one sample was positive for T. foetus by microscopy. By IFAT, four samples were positive for Giardia cysts and one for Cryptosporidium oocysts, none of which was co-infected with T. foetus. No significant associations were found between the presence of T. foetus and the various risk factors examined. Conclusions T. foetus was found to be a common parasite in clinically healthy cats in Norway.

  4. Photolysis of Br2 in CCl4 studied by time-resolved X-ray scattering.

    Science.gov (United States)

    Kong, Qingyu; Lee, Jae Hyuk; Lo Russo, Manuela; Kim, Tae Kyu; Lorenc, Maciej; Cammarata, Marco; Bratos, Savo; Buslaps, Thomas; Honkimaki, Veijo; Ihee, Hyotcherl; Wulff, Michael

    2010-03-01

    A time-resolved X-ray solution scattering study of bromine molecules in CCl(4) is presented as an example of how to track atomic motions in a simple chemical reaction. The structures of the photoproducts are tracked during the recombination process, geminate and non-geminate, from 100 ps to 10 micros after dissociation. The relaxation of hot Br(2)(*) molecules heats the solvent. At early times, from 0.1 to 10 ns, an adiabatic temperature rise is observed, which leads to a pressure gradient that forces the sample to expand. The expansion starts after about 10 ns with the laser beam sizes used here. When thermal artefacts are removed by suitable scaling of the transient solvent response, the excited-state solute structures can be obtained with high fidelity. The analysis shows that 30% of Br(2)(*) molecules recombine directly along the X potential, 60% are trapped in the A/A' state with a lifetime of 5.5 ns, and 10% recombine non-geminately via diffusive motion in about 25 ns. The Br-Br distance distribution in the A/A' state peaks at 3.0 A.

  5. Study on crack scattering in aluminum plates with Lamb wave frequency–wavenumber analysis

    International Nuclear Information System (INIS)

    Yu, Lingyu; Tian, Zhenhua; Leckey, Cara A C

    2013-01-01

    The multimodal characteristic of Lamb waves makes the interpretation of Lamb wave signals difficult in either the time or frequency domain. In this work, we present our study of Lamb wave propagation characterization and crack scattering using frequency–wavenumber analysis. The aim is to investigate three dimensional (3D) Lamb wave behavior in the presence of crack damage via the application of frequency–wavenumber analysis. The analysis techniques are demonstrated using simulation examples of an aluminum plate with a through-thickness crack. Both in-plane and out-of-plane components are acquired through a 3D elastodynamic finite integration technique (EFIT), while the out-of-plane component is also experimentally obtained using a scanning laser Doppler vibrometer for verification purposes. The time–space wavefield is then transformed to the frequency–wavenumber domain by a two dimensional (2D) Fourier transform and the out-of-plane EFIT results are compared to experimental measurements. The experimental and simulated results are found to be in close agreement. The frequency–wavenumber representation of in-plane and out-of-plane components shows clear distinction among various Lamb wave modes that are present. However, spatial information is lost during this 2D transformation. A short space 2D Fourier transform is therefore adopted to obtain the frequency–wavenumber spectra at various spatial locations, resulting in a space–frequency–wavenumber representation of the signal. The space–frequency–wavenumber analysis has shown its potential for indicating crack presence. (paper)

  6. Background Rejection of Charged Particles in the Simbol-X Telescope: Preliminary Study of Protons Scattering

    Science.gov (United States)

    Dell'Orto, E.; Barbera, M.; Bulgarelli, A.; Fioretti, V.; Malaguti, G.; Mineo, T.; Pareschi, G.; Rigato, V.; Spiga, D.; Tagliaferri, G.

    2009-05-01

    X-ray telescopes equipped with focusing optics in high eccentric orbit, as e.g. Newton-XMM and Chandra, showed a degradation of the detector performance and an important increase of the noise due to soft protons with energy between a few tens of keV and a few MeV, that are focused on the detector through the mirror module. It should be noted that the focusing of the protons by Wolter optics was an unexpected phenomenon. In Simbol-X a magnetic diverter will be implemented to deflect protons, in order to reduce the flux of charged particles impinging upon the focal plane. Obviously the design of the diverter should take into consideration the protons distribution at the exit of the mirror module; for this reason a detailed simulation about the interaction of particles with the mirror surface is necessary. Here we will present the scattering protons models currently under consideration, suggesting a preliminary solution for the design of the magnetic diverter. We will also discuss an ad hoc experiment to study this problem.

  7. Background Rejection of Charged Particles in the Simbol-X Telescope: Preliminary Study of Protons Scattering

    International Nuclear Information System (INIS)

    Dell'Orto, E.; Barbera, M.; Bulgarelli, A.; Fioretti, V.; Malaguti, G.; Mineo, T.; Pareschi, G.; Spiga, D.; Tagliaferri, G.; Rigato, V.

    2009-01-01

    X-ray telescopes equipped with focusing optics in high eccentric orbit, as e.g. Newton-XMM and Chandra, showed a degradation of the detector performance and an important increase of the noise due to soft protons with energy between a few tens of keV and a few MeV, that are focused on the detector through the mirror module. It should be noted that the focusing of the protons by Wolter optics was an unexpected phenomenon. In Simbol-X a magnetic diverter will be implemented to deflect protons, in order to reduce the flux of charged particles impinging upon the focal plane. Obviously the design of the diverter should take into consideration the protons distribution at the exit of the mirror module; for this reason a detailed simulation about the interaction of particles with the mirror surface is necessary. Here we will present the scattering protons models currently under consideration, suggesting a preliminary solution for the design of the magnetic diverter. We will also discuss an ad hoc experiment to study this problem.

  8. The study of membrane formation via phase inversion method by cloud point and light scattering experiment

    Science.gov (United States)

    Arahman, Nasrul; Maimun, Teuku; Mukramah, Syawaliah

    2017-01-01

    The composition of polymer solution and the methods of membrane preparation determine the solidification process of membrane. The formation of membrane structure prepared via non-solvent induced phase separation (NIPS) method is mostly determined by phase separation process between polymer, solvent, and non-solvent. This paper discusses the phase separation process of polymer solution containing Polyethersulfone (PES), N-methylpirrolidone (NMP), and surfactant Tetronic 1307 (Tet). Cloud point experiment is conducted to determine the amount of non-solvent needed on induced phase separation. Amount of water required as a non-solvent decreases by the addition of surfactant Tet. Kinetics of phase separation for such system is studied by the light scattering measurement. With the addition of Tet., the delayed phase separation is observed and the structure growth rate decreases. Moreover, the morphology of fabricated membrane from those polymer systems is analyzed by scanning electron microscopy (SEM). The images of both systems show the formation of finger-like macrovoids through the cross-section.

  9. Chloride ion-dependent surface-enhanced Raman scattering study of biotin on the silver surface

    International Nuclear Information System (INIS)

    Liu Fangfang; Gu Huaimin; Yuan Xiaojuan; Dong Xiao; Lin Yue

    2011-01-01

    In the present paper, the surface enhanced Raman scattering (SERS) technique was employed to study the SERS spectra of biotin molecules formed on the silver surface. The adsorption geometries of biotin molecules on the silver surface were analyzed based on the SERS data. It can be found that most vibration modes show a Raman shift in silver sol after the addition of sodium chloride solution. In addition, The Raman signals of biotin become weaker and weaker with the increase of the concentration of sodium chloride. This may be due to that the interaction between chloride ions and silver particles is stronger than the interaction between biotin molecules and silver particles. When the concentration of sodium chloride in silver colloid is higher than 0.05mol/L, superfluous chloride ions may form an absorption layer so that biotin can not be adsorbed on silver surface directly. The changes in intensity and profile shape in the SERS spectra suggest different adsorption behavior and surface-coverage of biotin on silver surface. The SERS spectra of biotin suggest that the contribution of the charge transfer mechanism to SERS may be dominant.

  10. Polyhydroxyalkanoate-based natural-synthetic hybrid copolymer films: A small-angle neutron scattering study

    International Nuclear Information System (INIS)

    Foster, L. John R.; Knott, Robert; Sanguanchaipaiwong, Vorapat; Holden, Peter J.

    2006-01-01

    Polyhydroxyalkanoates have attracted attention as biodegradable alternatives to conventional thermoplastics and as biomaterials. Through modification of their biosynthesis using Pseudomonas oleovorans, we have manipulated the material properties of these biopolyesters and produced a natural-synthetic hybrid copolymer of polyhydroxyoctanoate-block-diethylene glycol (PHO-b-DEG). A mixture of PHO and PHO-DEG were solvent cast from analytical grade chloroform and analysed using small-angle neutron scattering. A scattering pattern, easily distinguished above the background, was displayed by the films with a diffraction ring at q∼0.12 A -1 . This narrow ring of intensity is suggestive of a highly ordered system. Analysis of the diffraction pattern supported this concept and showed a d-spacing of approximately 50 A. In addition, conformation of the hybrid polymer chains can be manipulated to support their self-assembly into ordered microporous films

  11. Small angle neutron scattering study on short and long chain phosphatidylcholine mixture in trehalose solution

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Hiroshi [Department of Physics, Gunma University, Maebashi, Gunma (Japan)

    2001-03-01

    Trehalose protects cells and proteins against various stresses due to low temperatures or dryness. In order to clarify the molecular mechanism of cryoprotective function of trehalose, we have studied the interaction between trehalose and phosphatidylcholine (PC) which is a main lipid component of cell membranes. In this study, the structural change of a binary PC mixture by the presence of trehalose was investigated by means of small angle neutron scattering. The PC binary mixture studied contains dihexanoyl-PC (diC{sub 6}PC) and dihexadecy-PC (DHPC). The former has short hydrocarbon chains and the latter has long hydrocarbon chains. The scattering profiles from the DHPC/diC{sub 6}PC mixture were changed, depending on trehalose concentrations. This change can be interpreted as suggesting that the presence of trehalose reduces the interfacial area between water and PCs. (author)

  12. Molecular Dynamics and Neutron Scattering Studies of Mixed Solutions of Caffeine and Pyridine in Water.

    Science.gov (United States)

    Tavagnacco, Letizia; Mason, Philip E; Neilson, George W; Saboungi, Marie-Louise; Cesàro, Attilio; Brady, John W

    2018-05-31

    Insight into the molecular interactions of homotactic and heterotactic association of caffeine and pyridine in aqueous solution is given on the basis of both experimental and simulation studies. Caffeine is about 5 times more soluble in a 3 m aqueous pyridine solution than it is in pure water (an increase from ∼0.1 m to 0.5 m). At this elevated concentration the system becomes suitable for neutron scattering study. Caffeine-pyridine interactions were studied by neutron scattering and molecular dynamics simulations, allowing a detailed characterization of the spatial and orientational structure of the solution. It was found that while pyridine-caffeine interactions are not as strong as caffeine-caffeine interactions, the pyridine-caffeine interactions still significantly disrupted caffeine-caffeine stacking. The alteration of the caffeine-caffeine stacking, occasioned by the presence of pyridine molecules in solution and the consequent formation of heterotactic interactions, leads to the experimentally detected increase in caffeine solubility.

  13. Core polarisation and configuration mixing in 58Ni studied by high resolution electron scattering

    International Nuclear Information System (INIS)

    Blok, H.

    1986-01-01

    The nucleus 58 Ni is studied by inelastic electron-scattering. This nucleus has two valence neutrons outside a closed 58 Ni core which implies that no valence protons contribute to the transitions and thus, besides configuration mixing of the valence neutrons, proton-core polarization can be studied in detail. From inelastic electron-scattering data one obtains the charge- and current-transition densities by determining the Fourier-Bessel transform of the cross sections measured over a wide range of linear momenta transferred to the nucleus. The results of an analysis of the excitation of two 0 ++ states at low-momentum transfer are presented. These transitions are particularly interesting for studying core-polarization contributions. (Auth.)

  14. Studies of oxide-based thin-layered heterostructures by X-ray scattering methods

    Energy Technology Data Exchange (ETDEWEB)

    Durand, O. [Thales Research and Technology France, Route Departementale 128, F-91767 Palaiseau Cedex (France)]. E-mail: olivier.durand@thalesgroup.com; Rogers, D. [Nanovation SARL, 103 bis rue de Versailles 91400 Orsay (France); Universite de Technologie de Troyes, 10-12 rue Marie Curie, 10010 (France); Teherani, F. Hosseini [Nanovation SARL, 103 bis rue de Versailles 91400 Orsay (France); Andrieux, M. [LEMHE, ICMMOCNRS-UMR 8182, Universite d' Orsay, Batiment 410, 91410 Orsay (France); Modreanu, M. [Tyndall National Institute, Lee Maltings, Prospect Row, Cork (Ireland)

    2007-06-04

    Some X-ray scattering methods (X-ray reflectometry and Diffractometry) dedicated to the study of thin-layered heterostructures are presented with a particular focus, for practical purposes, on the description of fast, accurate and robust techniques. The use of X-ray scattering metrology as a routinely working non-destructive testing method, particularly by using procedures simplifying the data-evaluation, is emphasized. The model-independent Fourier-inversion method applied to a reflectivity curve allows a fast determination of the individual layer thicknesses. We demonstrate the capability of this method by reporting X-ray reflectometry study on multilayered oxide structures, even when the number of the layers constitutive of the stack is not known a-priori. Fast Fourier transform-based procedure has also been employed successfully on high resolution X-ray diffraction profiles. A study of the reliability of the integral-breadth methods in diffraction line-broadening analysis applied to thin layers, in order to determine coherent domain sizes, is also reported. Examples from studies of oxides-based thin-layers heterostructures will illustrate these methods. In particular, X-ray scattering studies performed on high-k HfO{sub 2} and SrZrO{sub 3} thin-layers, a (GaAs/AlOx) waveguide, and a ZnO thin-layer are reported.

  15. Insights into the interactions among Surfactin, betaines, and PAM: surface tension, small-angle neutron scattering, and small-angle X-ray scattering study.

    Science.gov (United States)

    Xiao, Jingwen; Liu, Fang; Garamus, Vasil M; Almásy, László; Handge, Ulrich A; Willumeit, Regine; Mu, Bozhong; Zou, Aihua

    2014-04-01

    The interactions among neutral polymer polyacrylamide (PAM) and the biosurfactant Surfactin and four betaines, N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SDDAB), N-tetradecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (STDAB), N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (SHDAB), and N-dodecyl-N,N-dimethyl-2-ammonio-acetate (C12BE), in phosphate buffer solution (PBS) have been studied by surface tension measurements, small-angle neutron scattering (SANS), small-angle X-ray scattering (SAXS), and rheological experiments. It has been confirmed that the length of alkyl chain is a key parameter of interaction between betaines and PAM. Differences in scattering contrast between X-ray and neutrons for surfactants and PAM molecules provide the opportunity to separately follow the changes of structure of PAM and surfactant aggregates. At concentrations of betaines higher than CMC (critical micelle concentration) and C2 (CMC of surfactant with the presence of polymer), spherical micelles are formed in betaines and betaines/PAM solutions. Transition from spherical to rod-like aggregates (micelles) has been observed in solutions of Surfactin and Surfactin/SDDAB (αSurfactin = 0.67 (molar fraction)) with addition of 0.8 wt % of PAM. The conformation change of PAM molecules only can be observed for Surfactin/SDDAB/PAM system. Viscosity values follow the structural changes suggested from scattering measurements i.e., gradually increases for mixtures PAM → Surfactin/PAM → Surfactin/SDDAB/PAM in PBS.

  16. Cadmium in Salix. A study to show the capacity of Salix to remove cadmium from farmland

    International Nuclear Information System (INIS)

    Oestman, G.

    1994-01-01

    The aim of this report has been to show the ability of Salix to take up cadmium and how the uptake varies between different types of soil. The information that the results are based on has been obtained from analyses of soil and Salix. The samples were taken at five sites in the district around Lake Maelaren. Two or three stands were taken at each place. The factors studied were the pH, the organic matter content, and the concentration of cadmium in the soil. Salix has a good ability, relative to other crops, to remove cadmium from arable land. The cadmium uptake is 35 times higher with Salix than with straw or energy grass. Salix uptake of cadmium varies between 3 and 14% of the cadmium content in the soil that is accessible to plants. The present annual increase of cadmium in arable land is 1 g/ha, whereas the removal in a Salix plantation is 21 g Cd/ha, yr at an annual growth of 10 tonnes DM. If the Cd uptake is the same each year, then a total of 420 g Cd/ha is removed when Salix is grown over a 20-year period. This is a very large part of the topsoil's total cadmium content, which is 550 g/ha on average in Sweden. The investigation reveals no clear relationship between the Cd concentration in Salix and the concentration of Cd in the soil, the organic matter content or the pH. 22 refs, 4 figs, 2 tabs

  17. Complement activation in leprosy: a retrospective study shows elevated circulating terminal complement complex in reactional leprosy.

    Science.gov (United States)

    Bahia El Idrissi, N; Hakobyan, S; Ramaglia, V; Geluk, A; Morgan, B Paul; Das, P Kumar; Baas, F

    2016-06-01

    Mycobacterium leprae infection gives rise to the immunologically and histopathologically classified spectrum of leprosy. At present, several tools for the stratification of patients are based on acquired immunity markers. However, the role of innate immunity, particularly the complement system, is largely unexplored. The present retrospective study was undertaken to explore whether the systemic levels of complement activation components and regulators can stratify leprosy patients, particularly in reference to the reactional state of the disease. Serum samples from two cohorts were analysed. The cohort from Bangladesh included multi-bacillary (MB) patients with (n = 12) or without (n = 46) reaction (R) at intake and endemic controls (n = 20). The cohort from Ethiopia included pauci-bacillary (PB) (n = 7) and MB (n = 23) patients without reaction and MB (n = 15) patients with reaction. The results showed that the activation products terminal complement complex (TCC) (P ≤ 0·01), C4d (P ≤ 0·05) and iC3b (P ≤ 0·05) were specifically elevated in Bangladeshi patients with reaction at intake compared to endemic controls. In addition, levels of the regulator clusterin (P ≤ 0·001 without R; P < 0·05 with R) were also elevated in MB patients, irrespective of a reaction. Similar analysis of the Ethiopian cohort confirmed that, irrespective of a reaction, serum TCC levels were increased significantly in patients with reactions compared to patients without reactions (P ≤ 0·05). Our findings suggests that serum TCC levels may prove to be a valuable tool in diagnosing patients at risk of developing reactions. © 2016 British Society for Immunology.

  18. Intramolecular diffusive motion in alkane monolayers studied by high-resolution quasielastic neutron scattering and molecular dynamics simulations

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Criswell, L.; Fuhrmann, D

    2004-01-01

    Molecular dynamics simulations of a tetracosane (n-C24H50) monolayer adsorbed on a graphite basal-plane surface show that there are diffusive motions associated with the creation and annihilation of gauche defects occurring on a time scale of similar to0.1-4 ns. We present evidence...... that these relatively slow motions are observable by high-energy-resolution quasielastic neutron scattering (QNS) thus demonstrating QNS as a technique, complementary to nuclear magnetic resonance, for studying conformational dynamics on a nanosecond time scale in molecular monolayers....

  19. Neutron scattering study of dynamical properties of liquid helium confined into porous media

    International Nuclear Information System (INIS)

    Albergamo, Francesco

    2001-01-01

    The study of liquid helium confined into porous materials should allow for a better understanding of the relation between superfluidity and Bose-Einstein condensation, lacking, at present, o f a satisfactory theoretical description. Experiments on confined liquid helium are quite difficult and samples should be prepared very carefully. One should know at best the confining material characteristics and should control the actual filling status of the porous sample. To achieve this condition, we added an experimental stage to the procedure commonly used in the studies conducted insofar. We conducted helium adsorption isotherms on each porous sample supposed to be used a s a confining sample. In this way we were able to know, with an high degree of precision, the amount of helium necessary to fill the porous sample. We also get information on macroscopic phenomena occurring during the filling procedure. Some experimental tricks have been used in order to avoid condensation of liquid helium into the injection capillary. Two inelastic neutron scattering techniques have been used in order to get information respectively on the mean kinetic energy per particle and on the elementary excitations spectrum. The kinetic energy measurements showed that confinement is responsible for a rise in this quantity. The elementary excitations measurements showed a correspondence between the capillary condensation process (detected by helium adsorption isotherms measurements) and the presence of elementary excitations typical of the liquid helium. Moreover, the long-wavelength elementary excitations are found to be perturbed in a way compatible with the system geometry. An intrinsic (at T=0.4 K) width of the roton peak is also found. (author) [fr

  20. XPS and ion beam scattering studies of leaching in simulated waste glass containing uranium

    International Nuclear Information System (INIS)

    Karim, D.P.; Pronko, P.P.; Marcuso, T.L.M.; Lam, D.J.; Paulikas, A.P.

    1980-01-01

    Glass samples (consisting of 2 mole % UO 3 dissolved in a number of complex borosilicate simulated waste glasses including Battelle 76-68) were leached for varying times in distilled water at 75 0 C. The glass surfaces were examined before and after leaching using x-ray photoemission spectroscopy and back-scattered ion beam profiling. Leached samples showed enhanced surface layer concentrations of several elements including uranium, titanium, zinc, iron and rare earths. An experiment involving the leaching of two glasses in the same vessel showed that the uranium surface enhancement is probably not due to redeposition from solution

  1. Study of morphological changes in scattering and optically anisotropic medium through correlation images

    Science.gov (United States)

    Jain, Neha; Shukla, Prashant; Singh, Jai

    2018-05-01

    Correlation images are very useful in determining the morphological changes. We have investigated the correlation image analysis on depolarization and retardance matrices of polystyrene and gelatine samples respectively. We observed that that correlation images have a potential to show a significant variation with change in the concentration of samples (polystyrene and gelatine). For polystyrene microspheres the correlation value decreases with increasing scattering coefficient. In gelatine samples the correlation also decreases with sample concentration. This variation in correlation for retardance shows the change in a birefringence property of gelatine solution.

  2. Proton dose calculation on scatter-corrected CBCT image: Feasibility study for adaptive proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yang-Kyun, E-mail: ykpark@mgh.harvard.edu; Sharp, Gregory C.; Phillips, Justin; Winey, Brian A. [Department of Radiation Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114 (United States)

    2015-08-15

    Purpose: To demonstrate the feasibility of proton dose calculation on scatter-corrected cone-beam computed tomographic (CBCT) images for the purpose of adaptive proton therapy. Methods: CBCT projection images were acquired from anthropomorphic phantoms and a prostate patient using an on-board imaging system of an Elekta infinity linear accelerator. Two previously introduced techniques were used to correct the scattered x-rays in the raw projection images: uniform scatter correction (CBCT{sub us}) and a priori CT-based scatter correction (CBCT{sub ap}). CBCT images were reconstructed using a standard FDK algorithm and GPU-based reconstruction toolkit. Soft tissue ROI-based HU shifting was used to improve HU accuracy of the uncorrected CBCT images and CBCT{sub us}, while no HU change was applied to the CBCT{sub ap}. The degree of equivalence of the corrected CBCT images with respect to the reference CT image (CT{sub ref}) was evaluated by using angular profiles of water equivalent path length (WEPL) and passively scattered proton treatment plans. The CBCT{sub ap} was further evaluated in more realistic scenarios such as rectal filling and weight loss to assess the effect of mismatched prior information on the corrected images. Results: The uncorrected CBCT and CBCT{sub us} images demonstrated substantial WEPL discrepancies (7.3 ± 5.3 mm and 11.1 ± 6.6 mm, respectively) with respect to the CT{sub ref}, while the CBCT{sub ap} images showed substantially reduced WEPL errors (2.4 ± 2.0 mm). Similarly, the CBCT{sub ap}-based treatment plans demonstrated a high pass rate (96.0% ± 2.5% in 2 mm/2% criteria) in a 3D gamma analysis. Conclusions: A priori CT-based scatter correction technique was shown to be promising for adaptive proton therapy, as it achieved equivalent proton dose distributions and water equivalent path lengths compared to those of a reference CT in a selection of anthropomorphic phantoms.

  3. Small-angle scattering, contrast variation and the study of complex composite materials: A study of the structure of carbon black

    International Nuclear Information System (INIS)

    Hjelm, R.P. Jr.; Seeger, P.A.; Wampler, W.A.

    1993-01-01

    Detailed studies are presented on the structure and aggregation of an experimental high surface area carbon black (HSA) using small-angle neutron scattering and the method of contrast variation. We find that the approximately 27 mn HSA particle form small, linear aggregates of average aggregation number 5 when suspended in cyclohexane. There is considerable density fluctuation in the interior of these particles, with the denser regions being toward the outer part of the spherically-averaged structure. This information would not have been obtained from studies of carbon black without solvent. The results will be applied to similar scattering studies on solvent-swollen bound rubber gels made from HSA-polyisoprene. These result show, however, that the strong internal fluctuations of the carbon black will limit the information that can be obtained on the structure and conformation of the elastomer in the gel. There are additional limitation from compositional heterogeneity of the sample

  4. Effects of Pressure on Stability of Biomolecules in Solutions Studied by Neutron Scattering

    Science.gov (United States)

    Bellissent-Funel, Marie-Claire-; Appavou, Marie-Sousai; Gibrat, Gabriel

    Studies of the pressure dependence on protein structure and dynamics contribute not only to the basic knowledge of biological molecules but have also a considerable relevance in full technology, like in food sterilization and pharmacy. Conformational changes induced by pressure as well as the effects on the protein stability have been mostly studied by optical techniques (optical absorption, fluorescence, phosphorescence), and by NMR. Most optical techniques used so far give information related to the local nature of the used probe (fluorescent or phosphorescent tryptophan). Small angle neutron scattering and quasi-elastic neutron scattering provide essential complementary information to the optical data, giving quantitative data on change of conformation of soluble globular proteins such as bovine pancreatic trypsin inhibitor (BPTI) and on the mobility of protons belonging to the protein surface residues.

  5. High-resolution nonresonant x-ray Raman scattering study on rare earth phosphate nanoparticles

    NARCIS (Netherlands)

    Huotari, Simo; Suljoti, Edlira; Sahle, Christoph J.; Raedel, Stephanie; Monaco, Giulio; de Groot, Frank M. F.

    2015-01-01

    We report high-resolution x-ray Raman scattering studies of high-order multipole spectra of rare earth 4d -> 4f excitations (the N-4,N-5 absorption edge) in nanoparticles of the phosphates LaPO4, CePO4, PrPO4, and NdPO4. We also present corresponding data for La 5p -> 5d excitations (the O-2,O-3

  6. Study of humic acids by small-angle X-ray and neutron scattering

    International Nuclear Information System (INIS)

    Timchenko, A.; Trubetskaya, O.; Kihara, H.

    1999-01-01

    Humic acids are an important component of natural ecological system and represent a polydisperse complex of natural biopolymers with molecular masses from several to hundreds kilodaltons. They are both a source of organic compounds and a protector against anthropogenic pollutions of biosphere. The aim of the report is to underline some possibilities of small-angle X-ray and neutron scattering to study HA and their fractions. (author)

  7. Small angle neutron scattering study of creep deformation and fracture of type 304 stainless steel

    International Nuclear Information System (INIS)

    Yoo, M.H.; Ogle, J.C.; Schneibel, J.H.; Swindeman, R.W.

    1983-01-01

    A small-angle neutron scattering (SANS) study has been performed to determine the size distribution of carbide precipitates that were formed during creep deformation in type 304 stainless steel. The hardening mechanism during primary creep by a fine dispersion of carbide particles in the matrix was confirmed by the SANS measurement and also by direct TEM observations. The size distribution of creep-induced cavities was also determined by SANS measurements after post-creep solution heat treatment. (author)

  8. Small angle neutron scattering study of creep deformation and fracture of Type 304 stainless steel

    International Nuclear Information System (INIS)

    Yoo, M.H.; Ogle, J.C.; Schneibel, J.H.; Swindeman, R.W.

    1982-01-01

    A small-angle neutron scattering (SANS) study has been performed to determine the size distribution of carbide precipitates that were formed during creep deformation in Type 304 stainless steel. The hardening mechanism during primary creep by a fine dispersion of carbide particles in the matrix was confirmed by the SANS measurement and also by direct TEM observations. The size distribution of creep-induced cavities was also determined by SANS measurements after post-creep solution heat treatment

  9. Optimisation of anomalous scattering and structural studies of proteins using synchrotron radiation

    International Nuclear Information System (INIS)

    Helliwell, J.R.

    1979-01-01

    Measurements from crystalline protein samples using SR can be conveniently divided into two classes. Firstly, small samples, large unit cells, the rapid collection of accurate high resolution data and dynamical studies can all benefit from the high intensity. Secondly, an important extension of the classical methods of protein structure determination arises from use of the tunability of SR for optimization of anomalous scattering and subsequent phase determination. This paper concentrates on this area of application. (author)

  10. Neutron-scattering study of low-energy excitations in triphenyl phosphite

    CERN Document Server

    Mayer, J; Massalska-Arodz, M; Janik, J A; Natkaniec, I; Steinsvoll, O

    2002-01-01

    The low-energy excitations in crystalline and glassy triphenyl phosphite were studied by inelastic incoherent neutron scattering with two different instruments. The results - the incoherent dynamic structure factor S(2 theta,omega) and the density of states G(omega) - were obtained using direct and inverted geometry time-of-flight spectrometers, respectively. The probable origin of the excess density of states in the glass (boson peak) is discussed. (orig.)

  11. Neutron-scattering study of low-energy excitations in triphenyl phosphite

    International Nuclear Information System (INIS)

    Mayer, J.; Krawczyk, J.; Massalska-Arodz, M.; Janik, J.A.; Natkaniec, I.; Steinsvoll, O.

    2002-01-01

    The low-energy excitations in crystalline and glassy triphenyl phosphite were studied by inelastic incoherent neutron scattering with two different instruments. The results - the incoherent dynamic structure factor S(2θ,ω) and the density of states G(ω) - were obtained using direct and inverted geometry time-of-flight spectrometers, respectively. The probable origin of the excess density of states in the glass (boson peak) is discussed. (orig.)

  12. A study of the dynamics of hydrogen in yttrium using inelastic neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Bennington, S M; Benham, M J; Ross, D K [Birmingham Univ. (UK). School of Physics and Space Research; Taylor, A D; Bowden, Z A [Rutherford Appleton Lab., Chilton (UK)

    1989-01-01

    The results of several high resolution inelastic scattering experiments on {alpha}-phase yttrium-hydrogen are presented including measurements of energy levels up to the fourth and a study of the splitting of certain states due to hydrogen-hydrogen interactions. An attempt is made to model the energy levels by using perturbed simple harmonic oscillator wavefunctions. This can account for most of the major features of the spectrum. (orig.).

  13. Studies on eletron scattering by hydrogen atoms through of a correlationed wave function

    International Nuclear Information System (INIS)

    Jacchieri, S.G.

    1982-01-01

    A correlationed wave function dependent of two adjustable parameters ( α e β), aiming describe a system formed by an electron and a hydrogen atom is studied. Some elastic differential cross-sections for several values of α and β parameters, scattering angle of 2 0 to 140 0 and energies of 50 eV and 680 eV are presented. (M.J.C.) [pt

  14. Study of a new approach to diagnose breast cancer based on synchrotron radiation scattering properties

    International Nuclear Information System (INIS)

    Conceicao, A.L.C.; Poletti, M.E.

    2012-01-01

    Full text: Breast cancer is the most frequently occurring cancer in women accounting for about 20% of all cancer deaths. This scenario is, among other factors, due to inherent limitations of the current clinical methods of diagnosis based on x-ray absorption. Meanwhile, recent researches have shown that the scattered radiation can provide information about the structures that compose a biological tissue, like breast tissue. Then, the information provided by x-ray scattering techniques can be used to identify breast cancer. In this work, we developed a classification model based on discriminant analysis of scattering profiles of 106 human breast samples histopathologically classified as normal tissue, benign and malignant lesion, at wide (WAXS) and small angle x-ray scattering (SAXS) regions. WAXS and SAXS experiments were carried out at the D12A-XRD1 and D02-SAXS2 beam lines in the National Synchrotron Light Laboratory (LNLS) in Campinas. For WAXS experiment, was used an x-ray beam energy of 11keV allowing to record the momentum transfer interval of 0.7nm -1 ≤(q=4π.sin(θ/2)/λ)≤70.5nm -1 on the NaI(Tl) detector. While for SAXS experiment was used an x-ray wavelength of 1.488 Angstrom, a two-dimensional detector and several sample-detector distances, allowing to get the range of 0.07nm -1 ≤q≤4.20nm -1 . The scattering profiles at both regions, for each sample were used to build the diagnosis model based on discriminant analysis. From WAXS data, differences related to position and intensity of the peaks of the molecular structures were found, when compared normal and pathological breast tissues. While for SAXS these differences were observed in supramolecular structures. The diagnostic model combining the information at WAXS and SAXS yield two linear functions which, allow to correlate changes at molecular scale with those at supramolecular level as well as, to classify correctly all samples analyzed in this study[1]. Finally, the results achieved in this

  15. The Kinetics of Crystallization of Colloids and Proteins: A Light Scattering Study

    Science.gov (United States)

    McClymer, Jim

    2002-01-01

    Hard-sphere colloidal systems serve as model systems for aggregation, nucleation, crystallization and gelation as well as interesting systems in their own right.There is strong current interest in using colloidal systems to form photonic crystals. A major scientific thrust of NASA's microgravity research is the crystallization of proteins for structural determination. The crystallization of proteins is a complicated process that requires a great deal of trial and error experimentation. In spite of a great deal of work, "better" protein crystals cannot always be grown in microgravity and conditions for crystallization are not well understood. Crystallization of colloidal systems interacting as hard spheres and with an attractive potential induced by entropic forces have been studied in a series of static light scattering experiments. Additionally, aggregation of a protein as a function of pH has been studied using dynamic light scattering. For our experiments we used PMMA (polymethylacrylate) spherical particles interacting as hard spheres, with no attractive potential. These particles have a radius of 304 nanometers, a density of 1.22 gm/ml and an index of refraction of 1.52. A PMMA colloidal sample at a volume fraction of approximately 54% was index matched in a solution of cycloheptyl bromide (CHB) and cis-decalin. The sample is in a glass cylindrical vial that is placed in an ALV static and dynamic light scattering goniometer system. The vial is immersed in a toluene bath for index matching to minimize flair. Vigorous shaking melts any colloidal crystals initially present. The sample is illuminated with diverging laser light (632.8 nanometers) from a 4x microscope objective placed so that the beam is approximately 1 cm in diameter at the sample location. The sample is rotated about its long axis at approximately 3.5 revolutions per minute (highest speed) as the colloidal crystal system is non-ergodic. The scattered light is detected at various angles using the

  16. Preliminary laboratory studies of the optical scattering properties of the crystal clouds

    Directory of Open Access Journals (Sweden)

    C. Saunders

    Full Text Available Ice crystal clouds have an influence on the radiative budget of the earth; however, the exact size and nature of this influence has yet to be determined. A laboratory cloud chamber experiment has been set up to provide data on the optical scattering behaviour of ice crystals at a visible wavelength in order to gain information which can be used in climate models concerning the radiative characteristics of cirrus clouds. A PMS grey-scale probe is used to monitor simultaneously the cloud microphysical properties in order to correlate these closely with the observed radiative properties. Preliminary results show that ice crystals scatter considerably more at 90° than do water droplets, and that the halo effects are visible in a laboratory-generated cloud when the ice crystal concentration is sufficiently small to prevent masking from multiple scattering.

    Key words. Meteorology and atmosphere dynamics · Climatology · Radiative process · Atmospheric composition and structure · Cloud physics and chemistry

  17. Fractal Structures on Silica Aerogels Containing Titanium: A Small Angle Neutron Scattering Study

    International Nuclear Information System (INIS)

    Widya Sari; Dian Fitriyani; Abdul Aziz Mohamed; Noordin Ibrahim

    2009-01-01

    Full text: The fractal structure of silica aerogels containing titanium has been investigated by means of small-angle neutron scattering (SANS) technique. The SANS experiments were conducted using a 36 meter SANS BATAN spectrometer (SMARTer) in Serpong, Indonesia in the range of momentum transfer Q, 0.006 -1 ) < 0.3. The power-law for a fractal object scattering Q-D observed from all measured samples. The Fourier transform of pattern I(Q) a pair correlation model function was implemented in analyzing the structure factor from the power-law scattering profiles. The results are showing that the silica aerogels containing titanium has a mass fractal where its dimension DM is larger than the pure silica aerogels. The mass fractal dimension of silica aerogels containing titanium is relatively constant between 2.23 to 2.40 with the decrease of acid concentrations during a sol-gel process and formed a nanometer size of aggregate. Those fractal structures were simulated using a Delphi language and the results are presented in this paper. (author)

  18. Self-assembly behavior of discotic liquid crystals studied by neutron and X-ray scattering

    International Nuclear Information System (INIS)

    Kim, Hyo Sik

    2011-02-01

    We investigate both thermotropic and lyotropic phase behaviors in DLC molecules with detailed structural analysis which was performed by scattering methods such as small angle neutron scattering (SANS) and grazing incidence x-ray scattering (GIXS) techniques. First, for the study of thermotropic phase behavior in DLC, uniaxially oriented and well-ordered cobalt octa(n-decylthio)porphyrazine (CoS10) molecules in thin-film was used as a model molecule. Second, the lyotropic phase behavior in DLC was studied using model system, hexa-n-dodecyl-hexa-peri-hexabenzocoronene (HBC-C12) in organic solvent (p-xylene). The method for uniaxially oriented and highly ordered columnar superstructure of CoS10 on a large area of substrate (3 cm x 3 cm) has been developed by using applied magnetic field (ca. 1.0 T) and surface interaction simultaneously. When spin-coated CoS10 thin film on an OTS-functionalized silicon substrate was cooled from its isotropic phase to liquid crystalline phase in the presence of an applied magnetic field, the CoS10 formed uniaxially oriented and 'edge-on' arrangement of columnar superstructures with their columnar directors perpendicular to the applied magnetic field. Grazing incidence x-ray scattering (GIXS) measurements showed that CoS10 columns form rectangular columnar packing with a tilted arrangement against the columnar axis (ca. 40 .deg.) in columns. The effects of film thickness on the columnar packing structure in supported thin-films of CoS10 have been investigated by the GISAXS technique, with magnetically aligned CoS10 films on OTS-functionalized substrates used as model systems. CoS10 columnar superstructures in thin-films with thicknesses ranging from 49 nm to 845 nm were uniaxially oriented with 'edge-on' arrangement using magnetic field and surface interaction. The orientational ordering of the columnar packing in the plane perpendicular to the applied magnetic field is strongly dependent on the film thickness. While it is damped by

  19. Studies of Scattering, Reflectivity, and Transmitivity in WBAN Channel: Feasibility of Using UWB

    Science.gov (United States)

    Kabir, Md. Humaun; Ashrafuzzaman, Kazi; Chowdhury, M. Sanaullah; Kwak, Kyung Sup

    2010-01-01

    The Wireless Personal Area Network (WPAN) is one of the fledging paradigms that the next generation of wireless systems is sprouting towards. Among them, a more specific category is the Wireless Body Area Network (WBAN) used for health monitoring. On the other hand, Ultra-Wideband (UWB) comes with a number of desirable features at the physical layer for wireless communications. One big challenge in adoption of UWB in WBAN is the fact that signals get attenuated exponentially. Due to the intrinsic structural complexity in human body, electromagnetic waves show a profound variation during propagation through it. The reflection and transmission coefficients of human body are highly dependent upon the dielectric constants as well as upon the frequency. The difference in structural materials such as fat, muscles and blood essentially makes electromagnetic wave attenuation to be different along the way. Thus, a complete characterization of body channel is a challenging task. The connection between attenuation and frequency of the signal makes the investigation of UWB in WBAN an interesting proposition. In this paper, we study analytically the impact of body channels on electromagnetic signal propagation with reference to UWB. In the process, scattering, reflectivity and transmitivity have been addressed with analysis of approximate layer-wise modeling, and with numerical depictions. Pulses with Gaussian profile have been employed in our analysis. It shows that, under reasonable practical approximations, the human body channel can be modeled in layers so as to have the effects of total reflections or total transmissions in certain frequency bands. This could help decide such design issues as antenna characteristics of implant devices for WBAN employing UWB. PMID:22219673

  20. Studies of Scattering, Reflectivity, and Transmitivity in WBAN Channel: Feasibility of Using UWB

    Directory of Open Access Journals (Sweden)

    Md. Humaun Kabir

    2010-06-01

    Full Text Available The Wireless Personal Area Network (WPAN is one of the fledging paradigms that the next generation of wireless systems is sprouting towards. Among them, a more specific category is the Wireless Body Area Network (WBAN used for health monitoring. On the other hand, Ultra-Wideband (UWB comes with a number of desirable features at the physical layer for wireless communications. One big challenge in adoption of UWB in WBAN is the fact that signals get attenuated exponentially. Due to the intrinsic structural complexity in human body, electromagnetic waves show a profound variation during propagation through it. The reflection and transmission coefficients of human body are highly dependent upon the dielectric constants as well as upon the frequency. The difference in structural materials such as fat, muscles and blood essentially makes electromagnetic wave attenuation to be different along the way. Thus, a complete characterization of body channel is a challenging task. The connection between attenuation and frequency of the signal makes the investigation of UWB in WBAN an interesting proposition. In this paper, we study analytically the impact of body channels on electromagnetic signal propagation with reference to UWB. In the process, scattering, reflectivity and transmitivity have been addressed with analysis of approximate layer-wise modeling, and with numerical depictions. Pulses with Gaussian profile have been employed in our analysis. It shows that, under reasonable practical approximations, the human body channel can be modeled in layers so as to have the effects of total reflections or total transmissions in certain frequency bands. This could help decide such design issues as antenna characteristics of implant devices for WBAN employing UWB.

  1. Studying the Effect of a Competitive Game Show in a Learning by Teaching Environment

    Science.gov (United States)

    Matsuda, Noboru; Yarzebinski, Evelyn; Keiser, Victoria; Raizada, Rohan; Stylianides, Gabriel J.; Koedinger, Kenneth R.

    2013-01-01

    In this paper we investigate how competition among tutees in the context of learning by teaching affects tutors' engagement as well as tutor learning. We conducted this investigation by incorporating a competitive Game Show feature into an online learning environment where students learn to solve algebraic equations by teaching a synthetic…

  2. Sauerbraten, Rotkappchen und Goethe: The Quiz Show as an Introduction to German Studies.

    Science.gov (United States)

    White, Diane

    1980-01-01

    Proposes an adaptation of the quiz-show format for classroom use, discussing a set of rules and sample questions designed for beginning and intermediate German students. Presents questions based on German life and culture which are especially selected to encourage participation from students majoring in subjects other than German. (MES)

  3. A compact new incoherent Thomson scattering diagnostic for low-temperature plasma studies

    Science.gov (United States)

    Vincent, Benjamin; Tsikata, Sedina; Mazouffre, Stéphane; Minea, Tiberiu; Fils, Jérôme

    2018-05-01

    Incoherent Thomson scattering (ITS) has a long history of application for the determination of electron density and temperature in dense fusion plasmas, and in recent years, has been increasingly extended to studies in low-temperature plasma environments. In this work, the design and preliminary implementation of a new, sensitive and uniquely compact ITS platform known as Thomson scattering experiments for low temperature ion sources are described. Measurements have been performed on a hollow cathode plasma source, providing access to electron densities as low as 1016 m‑3 and electron temperatures of a few eV and below. This achievement has been made possible by the implementation of a narrow volume Bragg grating notch filter for the attenuation of stray light, a feature which guarantees compactness and reduced transmission losses in comparison to standard ITS platforms.

  4. Study of the nuclear continuum of 28Si after excitation by inelastic 6Li scattering

    International Nuclear Information System (INIS)

    Seegert, G.

    1985-01-01

    For the study of the direct reaction mechanisms which contribute in the inelastic 6 Li scattering to the nuclear continuum of 28 Si at the Karlsruhe Isochronous Cyclotron particle-particle coincidence experiments were performed at an incident 6 Li energy of 156 MeV. Thereby the inelastically scattered 6 Li ions were measured in Si semiconductor telescopes under an angle of THETA=11 0 respectively 10 0 , while the coincident charged particles, mainly α particles with an energy of 70 MeV and protons with an energy up to 50 MeV could be detected in an angular range of -85 0 0 and three angles beyond the reaction plane. For a limited angular range simultaneously the α and 3 He fragments produced by the breakup of the 6 Li particle were taken up in coincidence with all light charged particles. (orig./HSI) [de

  5. Neutron Scattering in Hydrogenous Moderators, Studied by Time Dependent Reaction Rate Method

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, L G; Moeller, E; Purohit, S N

    1966-03-15

    The moderation and absorption of a neutron burst in water, poisoned with the non-1/v absorbers cadmium and gadolinium, has been followed on the time scale by multigroup calculations, using scattering kernels for the proton gas and the Nelkin model. The time dependent reaction rate curves for each absorber display clear differences for the two models, and the separation between the curves does not depend much on the absorber concentration. An experimental method for the measurement of infinite medium reaction rate curves in a limited geometry has been investigated. This method makes the measurement of the time dependent reaction rate generally useful for thermalization studies in a small geometry of a liquid hydrogenous moderator, provided that the experiment is coupled to programs for the calculation of scattering kernels and time dependent neutron spectra. Good agreement has been found between the reaction rate curve, measured with cadmium in water, and a calculated curve, where the Haywood kernel has been used.

  6. Small angle neutron scattering study on star di-block copolymers

    International Nuclear Information System (INIS)

    Ertugrul, O.

    2006-01-01

    Determining structural properties, phase transitions and stability of polymer mixtures is very important to produce new materials with desired and interesting properties. Small Angle Neutron Scattering Technique (SANS) has been one of the most powerful and intensely used methods for the characterization of polymers for last decades, m this study, we use a model based on Gaussian Random Phase Approximation (RPA) to describe Star Di-block Copolymers (SDC) mixtures with homo-polymers. We could able to predict the miscibility and phase transitions of the various mixtures along with their structure factors, producing a thermodynamic picture of the system. Also the results suggest that scattering intensity will be dictated by the structure factor of the core or shell parts of star polymer only, which depends on the homo-polymer type of the mixture

  7. Study of the defect structures produced by heavy ions in dielectrics by means of small angle scattering

    International Nuclear Information System (INIS)

    Albrecht, D.J.

    1983-11-01

    The aim of the present thesis was to study the defects in dielectrics produced by fast ions. For this the small angle scattering was proved as suitable method. By the production by means of the ion beam of an accelerator the defects possess a pronounced preferential direction. In scattering experiments this system of scattering centers is distinguished by its unusually strong dependence of the sample orientation according to the primary beam. This property was studied, described, and illustrated by examples, and it could by shown that from this additional informations about the scattering defects can be derived. For the first time nuclear tracks were detected by means of small angle neutron scattering. It could be shown that here the same results are obtained as by small angle X-ray scattering. The measured intensity distributions could be assigned to a mathematical model description which gives form, width, and density of the tracks in the position space. On the base of this cylinder model computer codes were established which simulate the scattering experiment regarding the main influences and calculate the expected theoretical intensity distribution. The agreement between calculated and measured scattering distributions proves the validity of the model. The parameters determined by this model, maximal change of density in the track, defect length, radial dilatation, distance of the narrowings and there depth were determined. For the main quantities, radial dilatation and maximal change of densities a simple description of the energy dependence could be given via the energy loss. (orig./HSI) [de

  8. a Time-Resolved X-Ray Scattering Study of the Ordering Kinetics in COPPER(3)-GOLD

    Science.gov (United States)

    Shannon, Robert Francis, Jr.

    Time-resolved x-ray scattering has been used to study ordering kinetics in single crystal bulk Cu _3Au, as well as in sputtered and molecular beam epitaxy grown films. After annealing at high temperatures the sample is rapidly quenched to fixed temperatures below the order-disorder transition temperature. The development of order is monitored in real time using scattering techniques. The bulk sample clearly showed three regimes: nucleation, ordering, and coarsening. The anisotropic superlattice peaks that reflect the domains structure are investigated in connection with the ordering kinetics. The line shape of the scattering function exhibits a crossover from gaussian to lorentzian-squared as the system goes from the ordering regime to the coarsening regime. Coarsening in Cu_3Au is consistent with curvature driven growth. Domain coarsening in stoichiometric sputtered films is also consistent with curvature driven growth. However, coarsening in copper rich films proceeds much more slowly. The results suggest the extra copper affects the ordering kinetics in the same way diffusive impurities would, resulting in a logarithmic like time dependence. The M.B.E. films show a slowing of the growth at late times. The 4500A film starts out with curvature driven growth but then continuously slows down as the domains grow. The 710A film shows an interesting temperature dependence for the growth, in such a way that at temperatures close to the transition, the domain growth almost freezes at late times. The dominate factor is probably strain, all of the trends for slower growth are consistent with greater strain. The dimensionality in the M.B.E. film systems is considered. The scaling in the 4500A and 710A films is clearly three dimensional. However, the dimension of the scaling in the 260A film is unclear.

  9. Neutron scattering studies in the actinide region. Progress report, August 1, 1991--July 31, 1994

    International Nuclear Information System (INIS)

    Kegel, G.H.R.; Egan, J.J.

    1994-09-01

    During the period August 1, 1991 to July 31, 1994 the authors report progress on the following: (a) prompt fission neutron energy spectra for 235 U and 239 Pu; (b) two-parameter measurement of nuclear lifetimes; (c) 'black' neutron detector; (d) data reduction techniques for neutron scattering experiments; (e) elastic and inelastic neutron scattering studies in 197 Au; (f) elastic and inelastic neutron scattering studies in 239 Pu; (g) neutron induced defects in silicon dioxide MOS structures; (h) response of a 235 U fission chamber near reaction thresholds; (i) efficiency calibration of a liquid scintillation detector using the WNR facility at LAMPF; (j) prompt fission neutron energy spectrum measurements below the incident neutron energy; (k) multi-parameter data acquisition system; (l) accelerator improvements; (m) non-DOE supported research. Eight Ph.D. dissertations and two M.S. theses were completed during the report period. Publications consisted of 6 journal articles, 10 conference proceedings, and 19 abstracts of presentations at scientific meetings. One invited talk was given

  10. Elastic helium scattering studies of ordered overlayers of Ar, Kr, and Xe physisorbed on Ag(111)

    International Nuclear Information System (INIS)

    Gibson, K.D.; Cerjan, C.; Light, J.C.; Sibener, S.J.

    1988-01-01

    We describe experiments that measured the angle resolved intensity of He (E/sub i/ = 18 and 66 meV) elastically scattering from the surfaces of rare gas overlayers physisorbed on Ag(111). These studies were done on a layer-by-layer basis for 1, 2, 3, and ∼25 ordered overlayers of Ar, Kr, and Xe. Two types of experiments are described. The first is diffraction, where the scattered He intensity was measured as a function of the detector angle, with the incident polar and azimuthal angles held constant. In the second type of experiment, selective adsorption, we measured the specular intensity as a function of incident angle. The purpose of these experiments was to examine the He--surface potential, to assess the relative contributions that various He--rare gas pair potentials, nonadditive multibody terms, and He--substrate interactions make to the systems studied. The experiments are compared with the results of accurate close-coupling calculations, in order to quantitatively perform these assessments. The comparisons between the selective adsorption data and scattering calculations demonstrate the extreme sensitivity that such measurements have to the He--surface potential. In particular, observable changes in the calculated selective adsorption spectra appear when different He--rare gas potentials are tested, or when various nonadditive terms are included in the potential. The results suggest that further refinements in the He-heavy--rare gas pair potentials may be in order

  11. Effective interactions in lysozyme aqueous solutions: a small-angle neutron scattering and computer simulation study.

    Science.gov (United States)

    Abramo, M C; Caccamo, C; Costa, D; Pellicane, G; Ruberto, R; Wanderlingh, U

    2012-01-21

    We report protein-protein structure factors of aqueous lysozyme solutions at different pH and ionic strengths, as determined by small-angle neutron scattering experiments. The observed upturn of the structure factor at small wavevectors, as the pH increases, marks a crossover between two different regimes, one dominated by repulsive forces, and another one where attractive interactions become prominent, with the ensuing development of enhanced density fluctuations. In order to rationalize such experimental outcome from a microscopic viewpoint, we have carried out extensive simulations of different coarse-grained models. We have first studied a model in which macromolecules are described as soft spheres interacting through an attractive r(-6) potential, plus embedded pH-dependent discrete charges; we show that the uprise undergone by the structure factor is qualitatively predicted. We have then studied a Derjaguin-Landau-Verwey-Overbeek (DLVO) model, in which only central interactions are advocated; we demonstrate that this model leads to a protein-rich/protein-poor coexistence curve that agrees quite well with the experimental counterpart; experimental correlations are instead reproduced only at low pH and ionic strengths. We have finally investigated a third, "mixed" model in which the central attractive term of the DLVO potential is imported within the distributed-charge approach; it turns out that the different balance of interactions, with a much shorter-range attractive contribution, leads in this latter case to an improved agreement with the experimental crossover. We discuss the relationship between experimental correlations, phase coexistence, and features of effective interactions, as well as possible paths toward a quantitative prediction of structural properties of real lysozyme solutions. © 2012 American Institute of Physics

  12. Excessive users of violent video games do not show emotional desensitization: an fMRI study.

    Science.gov (United States)

    Szycik, Gregor R; Mohammadi, Bahram; Hake, Maria; Kneer, Jonas; Samii, Amir; Münte, Thomas F; Te Wildt, Bert T

    2017-06-01

    Playing violent video games have been linked to long-term emotional desensitization. We hypothesized that desensitization effects in excessive users of violent video games should lead to decreased brain activations to highly salient emotional pictures in emotional sensitivity brain regions. Twenty-eight male adult subjects showing excessive long-term use of violent video games and age and education matched control participants were examined in two experiments using standardized emotional pictures of positive, negative and neutral valence. No group differences were revealed even at reduced statistical thresholds which speaks against desensitization of emotion sensitive brain regions as a result of excessive use of violent video games.

  13. Structure of magnetic particles studied by small angle neutron scattering. [Magnetic colloid particles in stable liquid dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Cebula, D J; Charles, S W; Popplewell, J

    1981-03-01

    The purpose of this note is to show how the use of small angle neutron scattering (SANS) can provide fundamental information on the structure of magnetic colloid particles in stable liquid dispersion. A more detailed account elaborating the use of the technique to provide fundamental information on interactions will appear later. This contribution contains some principal results on particle structure. The technique of SANS provides a very sensitive means of measuring particle size by measuring the scattered neutron intensity, I(Q), as a function of scattered wave vector, Q.

  14. A Monte Carlo study of the energy spectra and transmission characteristics of scattered radiation from x-ray computed tomography.

    Science.gov (United States)

    Platten, David John

    2014-06-01

    Existing data used to calculate the barrier transmission of scattered radiation from computed tomography (CT) are based on primary beam CT energy spectra. This study uses the EGSnrc Monte Carlo system and Epp user code to determine the energy spectra of CT scatter from four different primary CT beams passing through an ICRP 110 male reference phantom. Each scatter spectrum was used as a broad-beam x-ray source in transmission simulations through seventeen thicknesses of lead (0.00-3.50 mm). A fit of transmission data to lead thickness was performed to obtain α, β and γ parameters for each spectrum. The mean energy of the scatter spectra were up to 12.3 keV lower than that of the primary spectrum. For 120 kVp scatter beams the transmission through lead was at least 50% less than predicted by existing data for thicknesses of 1.5 mm and greater; at least 30% less transmission was seen for 140 kVp scatter beams. This work has shown that the mean energy and half-value layer of CT scatter spectra are lower than those of the corresponding primary beam. The transmission of CT scatter radiation through lead is lower than that calculated with currently available data. Using the data from this work will result in less lead shielding being required for CT scanner installations.

  15. [Heart rate variability study based on a novel RdR RR Intervals Scatter Plot].

    Science.gov (United States)

    Lu, Hongwei; Lu, Xiuyun; Wang, Chunfang; Hua, Youyuan; Tian, Jiajia; Liu, Shihai

    2014-08-01

    On the basis of Poincare scatter plot and first order difference scatter plot, a novel heart rate variability (HRV) analysis method based on scatter plots of RR intervals and first order difference of RR intervals (namely, RdR) was proposed. The abscissa of the RdR scatter plot, the x-axis, is RR intervals and the ordinate, y-axis, is the difference between successive RR intervals. The RdR scatter plot includes the information of RR intervals and the difference between successive RR intervals, which captures more HRV information. By RdR scatter plot analysis of some records of MIT-BIH arrhythmias database, we found that the scatter plot of uncoupled premature ventricular contraction (PVC), coupled ventricular bigeminy and ventricular trigeminy PVC had specific graphic characteristics. The RdR scatter plot method has higher detecting performance than the Poincare scatter plot method, and simpler and more intuitive than the first order difference method.

  16. Study of the Threshold Anomaly in the Scattering of Li Isotopes on 27Al

    International Nuclear Information System (INIS)

    Fernandez Niello, J.O.; Figueira, J.M.; Abriola, D.; Arazi, A.; Capurro, O.A.; Marti, G.V.; Martinez Heinmann, D.; Pacheco, A.J.; Barbara, E. de; Padron, I.; Gomes, P.R.S.; Lubian, J.

    2007-01-01

    Angular distributions of 6,7 Li scattered by 27 Al have been measured at different bombarding energies between 6 and 18 MeV. The results obtained from an optical model analysis using several potentials indicate that there is an isotopic dependence in the energy variation of the real and imaginary strengths. Whereas the 7 Li + 27 Al system shows no indication of any threshold anomaly, the 6 Li + 27 Al reaction suggests the presence of the so-called breakup threshold anomaly

  17. Study Of 9 Li-alpha Cluster States In 13B Using The Resonant Scattering Method

    CERN Document Server

    Fernandez-Garcia, Juan Pablo; Fisichella, M; Alcorta, M; Borge, M J G; Davinson, T; Figuera, P; Laird, A; Lattuada, M; Shotter, A C; Soic, N; Tengblad, O; Torresi, D; Zadro, M

    2017-01-01

    In order to investigate the compound nucleus 13B, the excitation function of the resonant reaction 4He(9Li,α) was measured. This measurement was carried out using the thick target inverse kinematics scattering technique, with a thick 4He gas target and a 9Li beam. The 13B energy region explored was in the excitation energy range 14 - 20 MeV, where 9Li-α configurations of 13B are predicted. The measured excitation function at θc.m.=180◦ shows different clear structures in a 13B excitation energy region which was experimentally unknown.

  18. Elastic neutron scattering studies at 96 MeV for transmutation.

    Science.gov (United States)

    Osterlund, M; Blomgren, J; Hayashi, M; Mermod, P; Nilsson, L; Pomp, S; Ohrn, A; Prokofiev, A V; Tippawan, U

    2007-01-01

    Elastic neutron scattering from (12)C, (14)N, (16)O, (28)Si, (40)Ca, (56)Fe, (89)Y and (208)Pb has been studied at 96 MeV in the10-70 degrees interval, using the SCANDAL (SCAttered Nucleon Detection AssembLy) facility. The results for (12)C and (208)Pb have recently been published, while the data on the other nuclei are under analysis. The achieved energy resolution, 3.7 MeV, is about an order of magnitude better than for any previous experiment above 65 MeV incident energy. A novel method for normalisation of the absolute scale of the cross section has been used. The estimated normalisation uncertainty, 3%, is unprecedented for a neutron-induced differential cross section measurement on a nuclear target. Elastic neutron scattering is of utmost importance for a vast number of applications. Besides its fundamental importance as a laboratory for tests of isospin dependence in the nucleon-nucleon, and nucleon-nucleus, interaction, knowledge of the optical potentials derived from elastic scattering come into play in virtually every application where a detailed understanding of nuclear processes is important. Applications for these measurements are dose effects due to fast neutrons, including fast neutron therapy, as well as nuclear waste incineration and single event upsets in electronics. The results at light nuclei of medical relevance ((12)C, (14)N and (16)O) are presented separately. In the present contribution, results on the heavier nuclei are presented, among which several are of relevance to shielding of fast neutrons.

  19. On the possibility of using X-ray Compton scattering to study magnetoelectrical properties of crystals

    Energy Technology Data Exchange (ETDEWEB)

    Collins, S. P., E-mail: steve.collins@diamond.ac.uk; Laundy, D.; Connolley, T.; Laan, G. van der; Fabrizi, F. [Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, OX11 0DE (United Kingdom); Janssen, O. [Department of Physics, New York University, New York, NY 10003 (United States); Cooper, M. J. [Department of Physics, University of Warwick, CV4 7AL (United Kingdom); Ebert, H.; Mankovsky, S. [Universität München, Department Chemie, Haus E2.033, Butenandtstrasse 5-13, D-81377 München (Germany)

    2016-02-16

    The possibility of using X-ray Compton scattering to reveal antisymmetric components of the electron momentum density, as a fingerprint of magnetoelectric sample properties, is investigated experimentally and theoretically by studying the polar ferromagnet GaFeO{sub 3}. This paper discusses the possibility of using Compton scattering – an inelastic X-ray scattering process that yields a projection of the electron momentum density – to probe magnetoelectrical properties. It is shown that an antisymmetric component of the momentum density is a unique fingerprint of such time- and parity-odd physics. It is argued that polar ferromagnets are ideal candidates to demonstrate this phenomenon and the first experimental results are shown, on a single-domain crystal of GaFeO{sub 3}. The measured antisymmetric Compton profile is very small (≃ 10{sup −5} of the symmetric part) and of the same order of magnitude as the statistical errors. Relativistic first-principles simulations of the antisymmetric Compton profile are presented and it is shown that, while the effect is indeed predicted by theory, and scales with the size of the valence spin–orbit interaction, its magnitude is significantly overestimated. The paper outlines some important constraints on the properties of the antisymmetric Compton profile arising from the underlying crystallographic symmetry of the sample.

  20. Quasielastic neutron scattering study of large amplitude motions in molecular systems

    International Nuclear Information System (INIS)

    Bee, M.

    1996-01-01

    This lecture aims at giving some illustrations of the use of Incoherent Quasielastic Neutron Scattering in the investigation of motions of atoms or molecules in phases with dynamical disorder. The general incoherent scattering function is first recalled. Then the Elastic Incoherent Structure Factor is introduced. It is shown how its determination permits to deduce a particular dynamical model. Long-range translational diffusion is illustrated by some experiments carried out with liquids or with different chemical species intercalated in porous media. Examples of rotational motions are provided by solid phases where an orientational disorder of the molecules exists. The jump model is the most commonly used and yields simple scattering laws which can be easily handled. Highly disordered crystals require a description in terms of the isotropic rotational diffusion model. Many of the present studies are concerned with rather complicated systems. Considerable help is obtained either by using selectively deuterated samples or by carrying out measurements with semi-oriented samples. (author) 5 figs., 14 refs

  1. Hard scattering on light nuclei: a convenient way to study parton correlations

    International Nuclear Information System (INIS)

    Calucci, G.; Treleani, D.

    2011-01-01

    The one-body partonic distributions in the hadrons are well investigated using electromagnetic or weak interactions. If we wish to exploit the same procedure to study the two-body distributions we should study the very rare events with multiple electromagnetic or weak interactions on the same hadron.The alternative is to study events with hard QCD double scattering of partons of the same hadron, such events become more and more abundant when the energy of the colliding hadrons grows. In fact at very high energies even the parton at small fractional momentum χ may suffer collisions with momentum transfer large enough to allow a perturbative treatment

  2. A case study of lightning attachment to flat ground showing multiple unconnected upward leaders

    Science.gov (United States)

    Cummins, Kenneth L.; Krider, E. Philip; Olbinski, Mike; Holle, Ronald L.

    2018-04-01

    On 10 July 2015, a cloud-to-ground (CG) lightning flash that produced two ground terminations was photographed from inside the safety of a truck in southern New Mexico. An analysis of archived NLDN data verified that this was a two-stroke flash, and a close-up view of the first stroke shows that it also initiated at least 12 unconnected, upward leaders (or "streamers") near the ground termination. No unconnected upward leaders were seen near the second ground attachment. After combining an analysis of the photograph with information provided by the NLDN, we infer that the first stroke was of negative (normal) polarity, had modest peak current, and struck about 460 m (± 24%) from the camera. Attachment occurred when an upward-propagating positive leader reached an inferred height of about 21 m above local ground. The second stroke struck ground about 740 m from the camera, and the height of its attachment leader is estimated to be 15 m. The estimated lengths of the unconnected upward leaders in the two-dimensional (2-D) plane of the first stroke range from 2 to 8 m, and all appear to be located within 15 m (2-D) of the main ground termination, with 24% uncertainty. Many of the unconnected upward leaders (inferred to be positive) exhibit multiple upward branches, and most of those branches have upward-directed forks or splits at their ends. This is the first report showing such extensive branching for positive upward leaders in natural lightning strikes to ground. None of the upward leaders can be seen to emanate from the tops of tall, isolated, or pointed objects on the ground, but they likely begin on small plants and rocks, or flat ground. In terms of lightning safety, this photo demonstrates that numerous upward leaders can be produced near a lightning strike point and have the potential to damage or cause injury at more than one specific point on the ground.

  3. Neutron scattering studies on dUTPase complex in the presence of bioprotectant systems

    Energy Technology Data Exchange (ETDEWEB)

    Varga, B. [Institute of Enzymology, Hungarian Academy of Sciences, POB 7, H-1518, Budapest (Hungary); Migliardo, F. [Dipartimento di Fisica, Universita di Messina, P.O. Box 55, I-98166 Messina (Italy); Takacs, E.; Vertessy, B. [Institute of Enzymology, Hungarian Academy of Sciences, POB 7, H-1518, Budapest (Hungary); Magazu, S. [Dipartimento di Fisica, Universita di Messina, P.O. Box 55, I-98166 Messina (Italy)], E-mail: smagazu@unime.it; Mondelli, C. [CNR-INFM OGG and CRS-SOFT, c/o ILL, BP 156, 38042 Grenoble Cedex 9 (France)

    2008-04-18

    The aim of the present work is to investigate the chemical physics mechanisms of protein stabilization by homologous disaccharides (trehalose, maltose and sucrose). On this purpose the structural and dynamical properties of dUTPase-inhibitor candidate and dUTPase-inhibitor candidate/disaccharide mixtures have been investigated by elastic neutron scattering (ENS), quasi-elastic neutron scattering (QENS) and photon correlation spectroscopy (PCS). The decrease in the ENS intensity profiles vs temperature for the disaccharide-water mixtures is less marked in the case of trehalose/water mixture. This indicates that trehalose shows a larger structural resistance to temperature changes and a higher 'rigidity' in comparison with maltose/H{sub 2}O and sucrose/H{sub 2}O mixtures. In addition the protein/hydrated-disaccharide mixtures show a linear dependence between the solvent viscosity and the local mean-square displacement of hydrated dUTpase/disaccharide systems. This result shows that the protein dynamics is coupled with that of the surrounding matrix. Furthermore, QENS results on the binary disaccharide-H{sub 2}O/D{sub 2}O mixtures indicate that the water dynamics is affected by all the disaccharides and particularly by trehalose. Finally, PCS findings indicate that the protein hydrodynamic radius in solution does not change at low disaccharide concentrations, while reveal, at high disaccharide concentration, a breakdown of the Stokes-Einstein law. The experimental findings are discussed and interpreted in the frame of the current theories.

  4. New study shows normally helpful natural bacteria may also trigger lupus | Center for Cancer Research

    Science.gov (United States)

    CCR scientists have discovered that a protein produced by bacteria that naturally inhabit our bodies may trigger the autoimmune disease lupus. The results of the study could unveil an entirely new set of drug targets for treating lupus and other autoimmune diseases. Read more…

  5. Older Adults Show Deficits in Retrieving and Decoding Associative Mediators Generated at Study

    Science.gov (United States)

    Hertzog, Christopher; Fulton, Erika K.; Mandviwala, Lulua; Dunlosky, John

    2013-01-01

    We instructed the use of mediators to encode paired-associate items, and then measured both cued recall of targets and mediators. Older adults (n = 49) and younger adults (n = 57) studied a mixed list of concrete and abstract noun pairs under instructions to either generate a sentence or an image to form a new association between normatively…

  6. Study of medication-free children with Tourette syndrome do not show imaging abnormalities

    DEFF Research Database (Denmark)

    Jeppesen, Signe Søndergaard; Debes, Nanette Mol; Simonsen, Helle Juhl

    2014-01-01

    BACKGROUND: Imaging studies of patients with Tourette's syndrome (TS) across different cohorts have shown alterations in gray and white matter in areas associated with the cortico-striato-thalamic-cortical (CSTC) pathways; however, no consistent findings have subsequently established a clear...

  7. Affiliation, joint venture or PSO? Case studies show why provider strategies differ.

    Science.gov (United States)

    1998-03-01

    Joint venture, affiliation or PSO? Here are three case studies of providers who chose different paths under Medicare risk, plus some key questions you'll want to ask of your own provider organization. Learn from these examples so you'll make the best contracting decisions.

  8. Material Rhetoric: Spreading Stones and Showing Bones in the Study of Prehistory

    NARCIS (Netherlands)

    Van Reybrouck, D.; de Bont, R.; Rock, J.

    2009-01-01

    Since the linguistic turn, the role of rhetoric in the circulation and the popular representation of knowledge has been widely accepted in science studies. This article aims to analyze not a textual form of scientific rhetoric, but the crucial role of materiality in scientific debates. It introduces

  9. A morphometric CT study of Down's syndrome showing small posterior fossa and calcification of basal ganglia

    International Nuclear Information System (INIS)

    Ieshima, A.; Yoshino, K.; Takashima, S.; Takeshita, K.; Kisa, T.

    1984-01-01

    We report characteristic and morphometric changes of cranial computed tomography (CT) with increasing age in 56 patients with Down's syndrome aged from 0 month to 37 years. Patients were compared with 142 normal controls aged 0 to 59 years. Width of ventricles, Sylvian fissures, posterior fossa, pons and cisterna magna were measured on CT. The incidences of the cavum septi pellucidi, cavum vergae and cavum veli interpositi and high density in the basal ganglia were examined. There was high incidence (10.7%) of bilateral calcification of basal ganglia in Down's syndrome, although that of pineal body and choroid plexus calcification was similar in Down's syndrome and controls. Basal ganglia calcification is more frequently seen in young Down's syndrome and may be related to the premature aging characteristic of Down's syndrome. The CT in Down's syndrome showed relatively small posterior fossa, small cerebellum, small brain stem and relatively large Sylvian fissures in those under one year of age. There was a high frequency of midline cava and large cisterna magna. There were no significant atrophic changes on CT except after the fifth decade comparing with controls. (orig.)

  10. Ion distributions at charged aqueous surfaces: Synchrotron X-ray scattering studies

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Wei [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Surface sensitive synchrotron X-ray scattering studies were performed to obtain the distribution of monovalent ions next to a highly charged interface at room temperature. To control surface charge density, lipids, dihexadecyl hydrogen-phosphate (DHDP) and dimysteroyl phosphatidic acid (DMPA), were spread as monolayer materials at the air/water interface, containing CsI at various concentrations. Five decades in bulk concentrations (CsI) are investigated, demonstrating that the interfacial distribution is strongly dependent on bulk concentration. We show that this is due to the strong binding constant of hydronium H3O+ to the phosphate group, leading to proton-transfer back to the phosphate group and to a reduced surface charge. Using anomalous reflectivity off and at the L3 Cs+ resonance, we provide spatial counterion (Cs+) distributions next to the negatively charged interfaces. The experimental ion distributions are in excellent agreement with a renormalized surface charge Poisson-Boltzmann theory for monovalent ions without fitting parameters or additional assumptions. Energy Scans at four fixed momentum transfers under specular reflectivity conditions near the Cs+ L3 resonance were conducted on 10-3 M CsI with DHDP monolayer materials on the surface. The energy scans exhibit a periodic dependence on photon momentum transfer. The ion distributions obtained from the analysis are in excellent agreement with those obtained from anomalous reflectivity measurements, providing further confirmation to the validity of the renormalized surface charge Poisson-Boltzmann theory for monovalent ions. Moreover, the dispersion corrections f0 and f00 for Cs+ around L3 resonance, revealing the local environment of a Cs+ ion in the solution at the interface, were extracted simultaneously with output of ion distributions.

  11. Analysis of allergen immunotherapy studies shows increased clinical efficacy in highly symptomatic patients

    DEFF Research Database (Denmark)

    Howarth, P; Malling, Hans-Jørgen; Molimard, M

    2011-01-01

    them. Thus, clinical studies of AIT can neither establish baseline symptom levels nor limit the enrolment of patients to those with the most severe symptoms. Allergen immunotherapy treatment effects are therefore diluted by patients with low symptoms for a particular pollen season. The objective...... tertiles). The difference observed in the average score in each tertile in active vs placebo-treated patients was assessed. This allowed an estimation of the efficacy that could be achieved in patients from sites where symptoms were high during the pollen season. Results:  An increased treatment effect...... of this analysis was to assess the effect possible to achieve with AIT in the groups of patients presenting the most severe allergic symptoms. Methods:  Study centres were grouped into tertiles categorized according to symptom severity scores observed in the placebo patients in each centre (low, middle and high...

  12. Measurements of sin2 θ/sub w/ from studies of the elastic scattering of neutrinos by protons and electrons

    International Nuclear Information System (INIS)

    Mann, A.K.

    1986-01-01

    This talk is intended as a brief report on studies of the elastic scattering of neutrinos by protons and electrons. Measurements of the ratios of muon antineutrino and muon neutrino elastic scattering on protons, and the corresponding ratio for elastic scattering on electrons minimize systematic experimental errors, and lead directly to values of the fundamental parameter of the electroweak interaction, the Weinberg Angle, with minimal ambiguity. Accordingly, the principal motivation in carrying out these studies was the desire to obtain and compare precise values of the Weinberg Angle from both the semileptonic and leptonic reactions as still another test of the basic validity of the standard electroweak theory. 10 refs., 11 figs

  13. 'Show me the money': financial incentives increase chlamydia screening rates among tertiary students: a pilot study.

    Science.gov (United States)

    Currie, Marian J; Schmidt, Matthias; Davis, Belinda K; Baynes, Anne M; O'Keefe, Elissa J; Bavinton, Tim P; McNiven, Michelle; Martin, Sarah J; Bowden, Francis J

    2010-03-01

    We hypothesise that text-messaging and financial incentives would increase tertiary student participation in chlamydia screening. A cross-sectional study was conducted over two phases on eight tertiary campuses during 2007. During Phase 1 (6 months) study activities were advertised through student organisations and media. Education and screening were offered during a range of student activities. During Phase 2 (4 days) education and screening were offered via text messages. Non-financial incentives were offered during Phase 1 and a $10 cash incentive was offered during Phase 2. Rates of specimens provided by students and the direct costs incurred during each phase were compared. 2786 students attended the 31 activities conducted in Phase 1. Of these, 627 students (22.5%) provided urine specimens for chlamydia testing. During Phase 2, the dissemination of 866 text messages resulted in urine specimens from 392 students (45.3%). Costs per test were AUD $175.11 in Phase 1 and AUD $27.13 in Phase 2. Compared with more labour intensive (and therefore more expensive) screening activities conducted over a 6-month period, offering a small financial incentive to tertiary students through text messaging over a 4-day period significantly increased participation in on-campus chlamydia screening. This model could readily be applied to other populations to increase participation in chlamydia screening.

  14. An Inelastic Neutron Scattering Study of Confined Surface Water on Rutile Nanoparticles

    International Nuclear Information System (INIS)

    Spencer, Elinor; Levchenko, Andrey; Ross, Nancy; Kolesnikov, Alexander I.; Boerio-Goates, Juliana; Woodfield, Brian; Navrotsky, Alexandra; Li, Guangshe

    2009-01-01

    The vibrational density of states (VDOS) for water confined on the surface of rutile-TiO2 nanoparticles has been extracted from low temperature inelastic neutron scattering spectra. Two rutile-TiO2 nanoparticle samples that differ in their respective levels of hydration, namely TiO2 0.37H2O (1) and TiO2 0.22H2O (2) have been studied. The temperature dependency of the heat capacities for the two samples has been quantified from the VDOS. The results from this study are compared with previously reported data for water confined on anatase-TiO2 nanoparticles.

  15. Theoretical and experimental study of resonant inelastic X-ray scattering for NiO

    International Nuclear Information System (INIS)

    Kotani, A.; Matsubara, M.; Uozumi, T.; Ghiringhelli, G.; Fracassi, F.; Dallera, C.; Tagliaferri, A.; Brookes, N.B.; Braicovich, L.

    2006-01-01

    Resonant inelastic X-ray scattering (RIXS) spectra for Ni 2p to 3d excitation and 3d to 2p de-excitation of NiO are studied both theoretically and experimentally. Theoretical calculations with a single impurity Anderson model (SIAM) describe the charge transfer (CT) and d-d excitations in RIXS, and detailed study is made for the CT energy. High resolution RIXS measurements reveal the precise d-d excitation structure and its polarization dependence, and they are well reproduced by the SIAM calculation

  16. LIGHT SOURCE: A simulation study of Tsinghua Thomson scattering X-ray source

    Science.gov (United States)

    Tang, Chuan-Xiang; Li, Ren-Kai; Huang, Wen-Hui; Chen, Huai-Bi; Du, Ying-Chao; Du, Qiang; Du, Tai-Bin; He, Xiao-Zhong; Hua, Jian-Fei; Lin, Yu-Zhen; Qian, Hou-Jun; Shi, Jia-Ru; Xiang, Dao; Yan, Li-Xin; Yu, Pei-Cheng

    2009-06-01

    Thomson scattering X-ray sources are compact and affordable facilities that produce short duration, high brightness X-ray pulses enabling new experimental capacities in ultra-fast science studies, and also medical and industrial applications. Such a facility has been built at the Accelerator Laboratory of Tsinghua University, and upgrade is in progress. In this paper, we present a proposed layout of the upgrade with design parameters by simulation, aiming at high X-ray pulses flux and brightness, and also enabling advanced dynamics studies and applications of the electron beam. Design and construction status of main subsystems are also presented.

  17. The application of small-angle neutron scattering to the study of mass transfer in clays

    International Nuclear Information System (INIS)

    Allen, A.J.; Baston, A.H.; Bourke, P.J.; Jefferies, N.L.

    1990-01-01

    An extensive study using small angle neutron scattering (SANS) has been made of the pore structures in London Clay and in Ca-montmorillonite. Using SANS contrast variation techniques, the accessibilities of the pores to D 2 O by diffusion and permeation have been studied. Characterisation of the accessibility to different parts of the pore structure is intended to provide input data for models of radionuclide transport through clay geological barriers, and to improve interpretation of laboratory experiments that measure sorption of radionuclides on clays. (author)

  18. Neutron scattering studies of the dynamics of biological systems as a function of hydration, temperature and pressure

    International Nuclear Information System (INIS)

    Trapp, Marcus

    2010-01-01

    Incoherent elastic and quasi-elastic neutron scattering were used to measure membrane and protein dynamics in the nano- to picosecond time and Angstrom length scale. The hydration dependent dynamics of DMPC model membranes was studied using elastic and quasi-elastic neutron scattering. The elastic experiments showed a clear shift of the temperature of the main phase transition to higher temperatures with decreasing hydration level. The performed quasi-elastic measurements demonstrated nicely the influence, hydration has on the diffusive motions of the head lipid groups. Different models are necessary to fit the Q-dependence of the elastic incoherent structure factor and show therefore the reduced mobility as a result of reduced water content. In addition to temperature, pressure as a second thermodynamic variable was used to explore dynamics of DMPC membranes. The ordering introduced by applying pressure has similar effect to decreased hydration, therefore both approaches are complementary. Covering three orders of magnitude in observation time, the dynamics of native AChE and its complexed counterpart in presence of Huperzin A was investigated in the range from 1 ns to 100 ps. The mean square displacements obtained from the elastic data allowed the determination of activation energies and gave evidence that a hierarchy of motions contributes to the enzymatic activity. Diffusion constants and residence times were extracted from the quasi-elastic broadening. (author) [fr

  19. Feasibility Study on the Development of Index that Shows Social and Cultural Acceptance of Nuclear Power

    International Nuclear Information System (INIS)

    Cho, SeongKyung; Choi, Seungho; Yoon, Hana; Song, Jiyeon

    2015-01-01

    In this context, it is necessary to manage and develop an index that can measure the level of public acceptance by establishing the terms of social/cultural public acceptance of nuclear power in a practical manner and by identifying influential factors of public acceptance. Developing an index itself is not intended to increase the public acceptance of nuclear power. This study intends to contribute to determining energy policy acceptable to the public by estimating the level of potential social conflicts related to nuclear power policies with eligible evaluation criteria on social/cultural acceptance and by reducing relevant social costs. Key conclusions and proposal of this research are as follows. First, the influential factors of acceptance are reliability of nuclear safety, risk perception of nuclear power and beneficial perception of nuclear power. Among them, reliability of nuclear safety appears to have the most influence. In addition, benefit perception of nuclear power at the social level is significantly higher than that at the individual level. However, in relation to risk perception, a gap between experts and the public is found as nuclear industry premises that accident does not occur while the public premises that accident may occur

  20. Radiance Assimilation Shows Promise for Snowpack Characterization: A 1-D Case Study

    Science.gov (United States)

    Durand, Michael; Kim, Edward; Margulis, Steve

    2008-01-01

    We demonstrate an ensemble-based radiometric data assimilation (DA) methodology for estimating snow depth and snow grain size using ground-based passive microwave (PM) observations at 18.7 and 36.5 GHz collected during the NASA CLPX-1, March 2003, Colorado, USA. A land surface model was used to develop a prior estimate of the snowpack states, and a radiative transfer model was used to relate the modeled states to the observations. Snow depth bias was -53.3 cm prior to the assimilation, and -7.3 cm after the assimilation. Snow depth estimated by a non-DA-based retrieval algorithm using the same PM data had a bias of -18.3 cm. The sensitivity of the assimilation scheme to the grain size uncertainty was evaluated; over the range of grain size uncertainty tested, the posterior snow depth estimate bias ranges from -2.99 cm to -9.85 cm, which is uniformly better than both the prior and retrieval estimates. This study demonstrates the potential applicability of radiometric DA at larger scales.

  1. Feasibility Study on the Development of Index that Shows Social and Cultural Acceptance of Nuclear Power

    Energy Technology Data Exchange (ETDEWEB)

    Cho, SeongKyung [Bangmok College of General Education at Myongji Univ., Yongin (Korea, Republic of); Choi, Seungho; Yoon, Hana; Song, Jiyeon [Domo Brodeur, Seoul (Korea, Republic of)

    2015-05-15

    In this context, it is necessary to manage and develop an index that can measure the level of public acceptance by establishing the terms of social/cultural public acceptance of nuclear power in a practical manner and by identifying influential factors of public acceptance. Developing an index itself is not intended to increase the public acceptance of nuclear power. This study intends to contribute to determining energy policy acceptable to the public by estimating the level of potential social conflicts related to nuclear power policies with eligible evaluation criteria on social/cultural acceptance and by reducing relevant social costs. Key conclusions and proposal of this research are as follows. First, the influential factors of acceptance are reliability of nuclear safety, risk perception of nuclear power and beneficial perception of nuclear power. Among them, reliability of nuclear safety appears to have the most influence. In addition, benefit perception of nuclear power at the social level is significantly higher than that at the individual level. However, in relation to risk perception, a gap between experts and the public is found as nuclear industry premises that accident does not occur while the public premises that accident may occur.

  2. Interaction between structurally different heteroexopolysaccharides and β-lactoglobulin studied by solution scattering and analytical ultracentrifugation

    DEFF Research Database (Denmark)

    Khan, Sanaullah; Birch, Johnny; Van Calsteren, Marie-Rose

    2018-01-01

    Despite a very large number of bacterial exopolysaccharides have been reported, detailed knowledge on their molecular structures and associative interactions with proteins is lacking. Small-angle X-ray scattering, dynamic light scattering and analytical ultracentrifugation (AUC) were used...

  3. Relation between speckle decorrelation and optical phase conjugation (OPC)-based turbidity suppression through dynamic scattering media: a study on in vivo mouse skin

    Science.gov (United States)

    Jang, Mooseok; Ruan, Haowen; Vellekoop, Ivo M.; Judkewitz, Benjamin; Chung, Euiheon; Yang, Changhuei

    2014-01-01

    Light scattering in biological tissue significantly limits the accessible depth for localized optical interrogation and deep-tissue optical imaging. This challenge can be overcome by exploiting the time-reversal property of optical phase conjugation (OPC) to reverse multiple scattering events or suppress turbidity. However, in living tissue, scatterers are highly movable and the movement can disrupt time-reversal symmetry when there is a latency in the OPC playback. In this paper, we show that the motion-induced degradation of the OPC turbidity-suppression effect through a dynamic scattering medium shares the same decorrelation time constant as that determined from speckle intensity autocorrelation – a popular conventional measure of scatterer movement. We investigated this decorrelation characteristic time through a 1.5-mm-thick dorsal skin flap of a living mouse and found that it ranges from 50 ms to 2.5 s depending on the level of immobilization. This study provides information on relevant time scales for applying OPC to living tissues. PMID:25657876

  4. A surface enhanced Raman scattering spectroscopic study of UO{sub 2}{sup 2+} at trace concentration

    Energy Technology Data Exchange (ETDEWEB)

    Franzen, Carola [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes; Carstensen, Lale [Technische Univ. Dresden (Germany); Firkala, T. [Helmholtz Institute Freiberg for Resource Technology, Freiberg (Germany); Steudtner, Robin [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology

    2017-06-01

    Techniques for rapid screening of uranium in environmental samples are needed. This study entails the development of Surface-Enhanced Raman scattering (SERS) spectroscopy for analyzing uranium(VI) in aqueous media with improved sensitivity.

  5. Nuclear structure studies by the scattering of medium-energy electrons: Progress report, September 1, 1986-June 30, 1987

    International Nuclear Information System (INIS)

    Teterson, G.A.; Hicks, R.S.; Dubach, J.F.; Miskimen, R.A.

    1987-06-01

    This paper discusses the experimental electron scattering studies at SLAC and Bates Accelerator Center. Some theoretical work on nucleon-nucleon interactions, electromagnetic interactions, weak interactions and nuclear structure are also discussed

  6. Nuclear structure studies by the scattering of medium-energy electrons. Progress report, October 1, 1980-July 31, 1981

    International Nuclear Information System (INIS)

    Peterson, G.A.

    1981-08-01

    Electron scattering experiments are in progress at the Bates Linear Accelerator in Middleton, Massachusetts. Both magnetic elastic and transverse inelastic scattering cross sections have been measured at 180 0 by the apparatus constructed and brought into operation in late 1977 by the University of Massachusetts. A liquid-nitrogen-cooled gas target is being used in a study of deuteron elastic magnetic scattering and electrodisintegration over a large energy range. A measurement of elastic magnetic and transverse inelastic scattering from 14 N has been started. Measurements of the elastic magnetic scattering from 13 C, 15 N, 27 Al, 29 Si, and 31 P have been completed. The data set on 15 N inelastic scattering are now complete and analysis of the data is in progress. A study of M8 transitions in 54 Fe and 60 Ni is nearing completion. Several papers are being written on these subjects. A measurement of the transverse quasi-elastic scattering from 56 Fe has been started. Planning for an experiment utilizing radioactive 14 C is underway. Large-basis shell model calculations pertaining to the above nuclei and others have been made. Theoretical calculations of exchange currents, nuclear convection currents, and other nuclear phenomena are in progress. Finally, considerations are being given to the design of an integrated storage-ring-experimental system

  7. Nuclear-structure studies by the scattering of medium-energy electrons. Progress report, October 1, 1980-July 31, 1981

    International Nuclear Information System (INIS)

    Peterson, G.A.

    1981-08-01

    Electron scattering experiments are in progress at the Bates Linear Accelerator in Middleton, Massachusetts. Both magnetic elastic and transverse inelastic scattering cross sections have been measured at 180 0 by the apparatus constructed and brought into operation in late 1977 by the University of Massachusetts. A liquid-nitrogen-cooled gas target is being used in a study of deuteron elastic scattering and electrodisintegration over a large energy range. A measurement of elastic magnetic and transverse inelastic scattering from 14 N has been started. Measurements of the elastic magnetic scattering from 13 C, 15 N, 27 Al, 29 Si, and 31 P have been completed. The data set on 15 N inelastic scattering are now complete and analysis of the data is in progress. A study of M8 transitions in 54 Fe and 60 Ni is nearing completion. A measurement of the transverse quasielastic scattering from 56 Fe has been started. Planning for an experiment utilizing radioactive 14 C is underway. Large-basis shell model calculations pertaining to the above nuclei and others have been made. Theoretical calculations of exchange currents, nuclear convection currents, and other nuclear phenomena are in progress. Finally, considerations are being given to the design of an integrated storage-ring-experimental system

  8. Study of Surface Enhanced Raman Scattering of Alizarin and Crystal Violet Dyes

    Science.gov (United States)

    Gopal, Ram; Swarnkar, Raj Kumar

    2010-06-01

    Surface enhanced Raman scattering (SERS) plays a vital role in analytical chemistry to characterize ultra trace quantity of organic compounds and biological samples. Two mechanisms have been considered to explain the SERS effect. The main contribution arises from a huge enhancement of the local electromagnetic field close to surface roughness of the metal structures, due to the excitation of a localized surface plasmon, while a further enhancement can be observed for molecules adsorbed onto specific sites when resonant charge transfer occurs. SERS signals have been observed from adsorbates on many metallic surfaces like Ag, Au, Ni, Cu etc. Additionally, metal oxide nanoparticles also show SERS signals It has now been established that SERS of analyte material is highly dependent on the type of substrate involved. Many types of nanostructures like nanofilms, nanorods, nanospheres etc. show highly efficient SERS signals. In particular, there are two routes available for the synthesis of these nanomaterials: the chemical route and the physical route. Chemical route involves many types of reducing agents and capping agents which can interfere in origin and measurement of these signals. The physical route avoids these anomalies and therefore it is suitable for the study of SERS phenomenon. Pulsed laser ablation in liquid medium is an excellent top down technique to produce colloidal solution of nanoparticles with desired shape and size having surface free from chemical contamination, which is essential requirement for surface application of nanoparticles. The present work deals with the study of SERS of Crystal violet dye and Alizarin group dye on Cu@ Cu_2O and Ag colloidal nanoparticles synthesized by pulsed laser ablation. M. Fleishchmann, P. J. Hendra, and A. J. McQuillian Chem. Phys. Lett., 26, 163, 1974. U. Wenning, B. Pettinger, and H. Wetzel Chem. Phys. Lett., 70, 49, 1980. S. C. Singh, R. K. Swarnkar, P. Ankit, M. C. Chattopadhyaya, and R. Gopal AIP Conf. Proc

  9. SASSIE: A program to study intrinsically disordered biological molecules and macromolecular ensembles using experimental scattering restraints

    Science.gov (United States)

    Curtis, Joseph E.; Raghunandan, Sindhu; Nanda, Hirsh; Krueger, Susan

    2012-02-01

    regions to vary dihedral angles, ensembles of structures can be generated. Additionally, simple two-body rigid-body rotations are supported with and without disordered regions. Generated structures can then be used to calculate small-angle scattering profiles which can then be filtered against experimentally determined data. Filtered structures can be visualized individually or as an ensemble using density plots. In the modular and expandable program framework the user can easily access our subroutines and structural coordinates can be easily obtained for study using other computational physics methods. Additional comments: The distribution file for this program is over 159 Mbytes and therefore is not delivered directly when download or Email is requested. Instead an html file giving details of how the program can be obtained is sent. Running time: Varies depending on application. Typically 10 minutes to 24 hours depending on the number of generated structures.

  10. Small angle neutron and x-ray scattering studies of self-assembled nano structured materials

    International Nuclear Information System (INIS)

    Choi, Sung Min

    2009-01-01

    Full text: Small angle neutron and x-ray scattering are very powerful techniques to investigate nano structured materials. In this presentation, examples of nano structured materials investigated by neutron and x-ray scattering will be presented. Part I: The unique anisotropic physical properties of columnar discotic liquid crystals (DLCs) have attracted considerable interest for their potential applications as electronic devices. For many practical applications, however, it is crucial to obtain uniaxially oriented and highly ordered columnar superstructures of DLC molecules covering macroscopic area. Here, we present a simple and straight-forward approach to fabricate uniaxially oriented and highly ordered columnar superstructures of cobalt octa(n-decylthio) porphyrazine (CoS 1 0), a discotic supra-molecule, in bulk and on substrates [1] over a macroscopic length scale, utilizing an applied magnetic field and the interaction of CoS 1 0 with an OTS-functionalized substrate. The details of the oriented and ordered columnar nano-structures are investigated by SANS and GISAXS. Part II: Self-assembly of one-dimensional (1D) nanoparticles with metallic or semiconducting properties into highly ordered superstructures using various interactions has been of great interest as a route towards materials with new functionalities. Here, we report a new phase diagram of negatively charged 1D nanoparticle (cROD) and cationic liposome (CL) complexes in water which exhibit three different highly ordered phases [2]. Small angle neutron and x-ray scattering measurements show that the cROD-CL complexes exhibit three different highly ordered phases, intercalated lamellar, doubly intercalated lamellar and centered rectangular phases, depending on particle curvature and electrostatic interactions. The new phase diagram can be used to understand and design new highly ordered self-assemblies of 1D nanoparticles in soft matter which provide new functionalities. (author)

  11. SCANDAL -- A facility for elastic neutron scattering studies in the 50--130 MeV range

    International Nuclear Information System (INIS)

    Klug, J.; Blomgren, J.; Atac, A.; Bergenwall, B.; Dangtip, S.; Elmgren, K.; Johansson, C.; Olsson, N.; Prokofiev, A.V.; Rahm, J.; Oberstedt, A.; Tovesson, F.; Eudes, Ph.; Haddad, F.; Kerveno, M.; Kirchner, T.; Lebrun, C.; Stuttge, L.; Slypen, I.; Michel, R.; Neumann, S.; Herpers, U.

    2001-01-01

    A facility for detection of scattered neutrons in the energy interval 50--130 MeV, SCANDAL (SCAttered Nucleon Detection AssembLy), has recently been installed at the 20--180 MeV neutron beam facility of the The Svedberg Laboratory, Uppsala. It is primarily intended for studies of elastic neutron scattering, but can be used for the (n,p) and (n,d) reaction experiments as well. The performance of the spectrometer is illustrated in measurements of the (n,p) and (n,n) reactions on 1 H and 12 C. In addition, the neutron beam facility is described in some detail

  12. The studies of radiation distorations in CdS single crystals by using a proton back-scattering method

    International Nuclear Information System (INIS)

    Grigor'ev, A.N.; Dikij, N.P.; Matyash, P.P.; Nikolajchuk, L.I.; Pivovar, L.I.

    1974-01-01

    The radiation defects in semiconducting CdS single crystals induced during doping with 140 keV Na ions (10 15 -2.10 16 ion/cm 2 ) were studied by the orientation dependence of 700 keV proton backscattering. The absence of discrete peaks in the scattered proton eneryg spectra indicates a small contribution of direct scattering at large angles. The defects formed during doping increase the fractionof dechanneled particles, which are then scattered at large anlges. No amorphization of CdS was observed at high Na ion dose 2x10 16 ion/cm 2

  13. SCANDAL--a facility for elastic neutron scattering studies in the 50-130 MeV range

    CERN Document Server

    Klug, J; Atac, A; Bergenwall, B; Dangtip, S; Elmgren, K; Johansson, C; Olsson, N; Pomp, S; Prokofiev, A V; Rahm, J; Tippawan, U; Jonsson, O; Nilsson, L; Renberg, P U; Nadel-Turonski, P; Ringbom, A; Oberstedt, A; Tovesson, F; Blideanu, V; Le Brun, C; Lecolley, J F; Lecolley, F R; Louvel, M; Marie, N; Schweitzer, C; Varignon, C; Eudes, P; Haddad, F; Kerveno, M; Kirchner, T; Lebrun, C; Stuttgé, L; Slypen, I; Smirnov, A N; Michel, R; Neumann, S; Herpers, U

    2002-01-01

    A facility for detection of scattered neutrons in the energy interval 50-130 MeV, SCAttered Nucleon Detection AssembLy (SCANDAL), has recently been installed at the 20-180 MeV neutron beam facility of The Svedberg Laboratory, Uppsala. It is primarily intended for studies of elastic neutron scattering, but can be used for (n,p) and (n,d) reaction experiments as well. The performance of the spectrometer is illustrated in measurements of the (n,p) and (n,n) reactions on sup 1 H and sup 1 sup 2 C. In addition, the neutron beam facility is described in some detail.

  14. Cascaded Bragg scattering in fiber optics.

    Science.gov (United States)

    Xu, Y Q; Erkintalo, M; Genty, G; Murdoch, S G

    2013-01-15

    We report on a theoretical and experimental study of cascaded Bragg scattering in fiber optics. We show that the usual energy-momentum conservation of Bragg scattering can be considerably relaxed via cascade-induced phase-matching. Experimentally we demonstrate frequency translation over six- and 11-fold cascades, in excellent agreement with derived phase-matching conditions.

  15. Energy Transfer in Scattering by Rotating Potentials

    Indian Academy of Sciences (India)

    Quantum mechanical scattering theory is studied for time-dependent Schrödinger operators, in particular for particles in a rotating potential. Under various assumptions about the decay rate at infinity we show uniform boundedness in time for the kinetic energy of scattering states, existence and completeness of wave ...

  16. Scattering and multiple scattering in disordered materials

    International Nuclear Information System (INIS)

    Weaver, R.L.; Butler, W.H.

    1992-01-01

    The papers in this section were presented at a joint session of symposium V on Applications of Multiple Scattering Theory and of Symposium P on Disordered Systems. They show that the ideas of scattering theory can help us to understand a very broad class of phenomena

  17. Simulation study on cross polarization scattering of ultrashort-pulse electromagnetic waves

    International Nuclear Information System (INIS)

    Katsuragawa, Naoki; Hojo, Hitoshi; Mase, Atushi

    1996-11-01

    Simulation study on cross polarization scattering of ultrashort-pulse electromagnetic waves due to magnetic fluctuations is presented. One-dimensional coupled wave equations for the ordinary and extraordinary modes are solved for incident unipolar sub-cycle pulses in an inhomogeneous magnetized plasma. It is shown that the peak frequencies in the frequency-spectral signals of the mode-converted reflected waves are determined from the Bragg resonance condition in the wave numbers of the ordinary mode, the extraordinary mode and the magnetic fluctuations for relatively short-wavelength localized magnetic fluctuations. (author)

  18. Electron impact scattering study of hypohalous acids HOX (X = F, Cl, Br, I)

    Science.gov (United States)

    Yadav, Hitesh; Bhutadia, Harshad; Prajapati, Dinesh; Desai, Hardik; Vinodkumar, Minaxi; Vinodkumar, P. C.

    2018-05-01

    In this article we aim to report total cross sections (TCS) QT, total elastic cross sections (Qel), total inelastic cross sections (Qinel) i.e. (total ionizations cross sections (Qion)+total electronic excitation cross sections (Qexc)) from threshold of the target to 5000 eV energy range. We have used a well-defined theoretical methodology Spherical Complex Optical Potential (SCOP) to compute QT, Qel and Qinel and Complex Scattering Potential - ionization contribution (CSP - ic) method to report the (Qion). The cross-sectional data reported here for the Hypohalous Acids is for the first time and the present data can become a guideline for the experimentalist to study these targets.

  19. Magnetic x-ray scattering studies of holmium using synchro- tron radiation

    International Nuclear Information System (INIS)

    Gibbs, D.; Moncton, D.E.; D'Amico, K.L.; Bohr, J.; Grier, B.H.

    1985-01-01

    We present the results of magnetic x-ray scattering experiments on the rare-earth metal holmium using synchrotron radiation. Direct high-resolution measurements of the nominally incommensurate magnetic satellite reflections reveal new lock-in behavior which we explain within a simple spin-discommensuration model. As a result of magnetoelastic coupling, the spin-discommensuration array produces additional x-ray diffraction satellites. Their observation further substantiates the model and demonstrates additional advantages of synchrotron radiation for magnetic-structure studies

  20. Malnutrition and myelin structure: an X-ray scattering study of rat sciatic and optic nerves

    International Nuclear Information System (INIS)

    Vargas, V.; Vargas, R.; Marquez, G.; Vonasek, E.; Mateu, L.; Luzzati, V.; Borges, J.

    2000-01-01

    Taking advantage of the fast and accurate X-ray scattering techniques recently developed in our laboratory, we tackled the study of the structural alterations induced in myelin by malnutrition. Our work was performed on sciatic and optic nerves dissected from rats fed with either a normal or a low-protein caloric diet, as a function of age (from birth to 60 days). By way of electrophysiological controls we also measured (on the sciatic nerves) the height and velocity of the compound action potential. Malnutrition was found to decrease the amount of myelin and to impair the packing order of the membranes in the sheaths. (orig.)

  1. Study of chemically unfolded {beta}-casein by means of small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Aschi, Adel [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 1060, Tunis (Tunisia)]. E-mail: aschi13@yahoo.fr; Gharbi, Abdelhafidh [Laboratoire de Physique de la Matiere Molle, Faculte des Sciences de Tunis, Campus Universitaire, 1060, Tunis (Tunisia); Daoud, Mohamed [Service de Physique de l' Etat Condense. CEA Saclay. 91191 Gif-sur-Yvette cedex (France); Douillard, Roger [Equipe de Biochimie des Macromolecules Vegetales, Centre de Recherche Agronomique, 2Esplanade R. Garros, BP 224, 51686 Reims cedex 2 (France); Calmettes, Patrick [Laboratoire Leon Brillouin, CEA Saclay, 91191 Gif-sur-Yvette cedex (France)

    2007-01-01

    {beta}-casein is a flexible amphiphilic milk protein which forms an unfolded conformation in presence of very high denaturant concentrations. The structure of {beta}-casein formed at the bulk was studied by small-angle neutron scattering (SANS). The value of the second virial coefficient of the protein solutions indicates that the interactions between the polypeptide chain and solvent are repulsive. The protein conformation is similar to an excluded volume chain. The corresponding values of the contour length, L, the statistical length, b and the apparent radius of the chain cross-section, R{sub c} are given.

  2. Interferometric scattering (iSCAT) microscopy: studies of biological membrane dynamics

    Science.gov (United States)

    Reina, Francesco; Galiani, Silvia; Shrestha, Dilip; Sezgin, Erdinc; Lagerholm, B. Christoffer; Cole, Daniel; Kukura, Philipp; Eggeling, Christian

    2018-02-01

    The study of the organization and dynamics of molecules in model and cellular membranes is an important topic in contemporary biophysics. Imaging and single particle tracking in this particular field, however, proves particularly demanding, as it requires simultaneously high spatio-temporal resolution and high signal-to-noise ratios. A remedy to this challenge might be Interferometric Scattering (iSCAT) microscopy, due to its fast sampling rates, label-free imaging capabilities and, most importantly, tuneable signal level output. Here we report our recent advances in the imaging and molecular tracking on phase-separated model membrane systems and live-cell membranes using this technique.

  3. Monitoring of scale deposition in petroleum pipelines by means of photon scattering: a preliminary study

    International Nuclear Information System (INIS)

    Meric, Ilker; Johansen, Geir A.

    2013-01-01

    In the petroleum industry precipitation of scale onto the inner walls of hydrocarbon pipelines poses a significant challenge as, unless treated appropriately, deposits such as sulfate and carbonate scales reduce the overall flow area and even lead to blockage of entire sections of the pipework. This may in turn result in costly production suspension and maintenance work. Therefore, monitoring and characterization of scale deposits can be said to be of great importance. In this work, a preliminary feasibility study is carried out in order to investigate the possibility of utilizing photon scattering for scale detection in multiphase oil/water/gas pipelines. (author)

  4. A neutron scattering study on the antiferromagnet in an exchange biased systems

    Energy Technology Data Exchange (ETDEWEB)

    Solina, Danica; Lott, Dieter; Fenske, Jochen; Schreyer, Andreas [Institute of Materials Research, GKSS Research Centre, Geesthacht (Germany); Schmidt, Wolfgang [Institut-Laue-Langevin, Grenoble (France); Wu, Yu-Chang; Lai, Chih-Huang [Department of Materials Science and Engineering, National Tsing Hua University, HsinChu (China)

    2008-07-01

    The magnetic structure of single crystal antiferromagnetic PtMn that biases CoFe has been studied using neutron scattering. Polarized neutron reflection (PNR) was used to determine the switching behaviour of the ferromagnetic layer and polarized neutron diffraction (PND) to probe the magnetic configuration of the anti-ferromagnetic layer. PNR suggests a combination of rotation and domain formation. Changes were observed in the PND patterns taken at points around the hysteresis loop. The diffraction data has been simulated with a 'twisting' of part of the anti-ferromagnetic layer as the ferromagnetic layer changes.

  5. Electrochemically adsorbed Pb on Ag (111) studied with grazing- incidence x-ray scattering

    International Nuclear Information System (INIS)

    Kortright, J.B.; Ross, P.N.; Melroy, O.R.; Toney, M.F.; Borges, G.L.; Samant, M.G.

    1989-04-01

    Grazing-incidence x-ray scattering studies of the evolution of electrochemically deposited layers of lead on silver (111) as a function of applied electrochemical potential are presented. Measurements were made with the adsorbed layers in contact with solution in a specially designed sample cell. The observed lead structures are a function of the applied potential and range from an incommensurate monolayer, resulting from underpotential deposition, to randomly oriented polycrystalline bulk lead, resulting from lower deposition potentials. These early experiments demonstrate the ability of in situ x-ray diffraction measurements to determine structures associated with electrochemical deposition. 6 refs., 4 figs

  6. Gel-chromatographic and light scattering study of the salmonella typhi endotoxin

    Energy Technology Data Exchange (ETDEWEB)

    Dezhelici, G; Dezhelici, N; Jusici, D [Zagreb Univ. (Yugoslavia)

    1977-01-01

    The endotoxin of Salmonella typhi, strain 0-901 extracted with 1 M sodium chloride was studied by gel-chromatography and light scattering. The extracted material consisted of two components: a high molecular weight endotoxin (5.6 milion dalton) and a lower molecular weight protein-polysaccharide complex (less than 66,000 dalton). The endotoxin component proved to be a highly polydispersed material. Estimation of various averages of gyration radii suggested a more compact structure of endotoxin particles than those obtained by the Boivin extraction method, possibly due to the tertiary structuring of polypeptide chains in the protein-lipopolysaccharide complex of the endotoxin particle.

  7. Wide-angle X-ray scattering study of heat-treated PEEK and PEEK composite

    Science.gov (United States)

    Cebe, Peggy; Lowry, Lynn; Chung, Shirley Y.; Yavrouian, Andre; Gupta, Amitava

    1987-01-01

    Samples of poly(etheretherketone) (PEEK) neat resin and APC-2 carbon fiber composite were subjected to various heat treatments, and the effect of quenching and annealing treatments was studied by wide-angle X-ray scattering. It is found that high-temperature treatments may introduce disorder into neat resin and composite PEEK when followed by rapid cooling. The disorder is metastable and can revert to ordered state when the material is heated above its glass transition temperature and then cooled slowly. The disorder may result from residual thermal stresses.

  8. High resolution measurements and study of the neutron inelastic scattering reaction on 56Fe

    International Nuclear Information System (INIS)

    Dupont, E.

    1998-01-01

    High resolution measures of neutrons inelastic scattering cross section, have been performed on 56 Fe from 862 KeV to 3 MeV. The time of flight method has been used on the GELINA source of the IRMM in Geel (Belgium). Four barium fluoride scintillators, placed around the samples, recorded the gamma rays emissions coming from the iron and the boron. A study of the correlations between the partial elastic and inelastic lengths has been performed taking into account first transmission measures realized at Geel. (A.L.B.)

  9. Feasability study of using the TFTR Thomson scattering system for q profile measurements

    International Nuclear Information System (INIS)

    Brizard, A.; Grewk, B.; Johnson, D.; LeBlanc, B.

    1986-01-01

    The results of a study made to determine the possibility of using the TFTR 76 channels Thomson scattering system to measure the direction of local magnetic fields in a tokamak plasma are presented. As this is a local measurement, this technique can in principle yield q profiles without the need of any de-convolution. The effect of the TFTR geometrical configuration and its various components on the expected measurement accuracy is discussed. The authors find that the measurement of q values within the inner half of the plasma should be possible, with only minor modification to the present TVTS system

  10. Study of chemically unfolded β-casein by means of small-angle neutron scattering

    International Nuclear Information System (INIS)

    Aschi, Adel; Gharbi, Abdelhafidh; Daoud, Mohamed; Douillard, Roger; Calmettes, Patrick

    2007-01-01

    β-casein is a flexible amphiphilic milk protein which forms an unfolded conformation in presence of very high denaturant concentrations. The structure of β-casein formed at the bulk was studied by small-angle neutron scattering (SANS). The value of the second virial coefficient of the protein solutions indicates that the interactions between the polypeptide chain and solvent are repulsive. The protein conformation is similar to an excluded volume chain. The corresponding values of the contour length, L, the statistical length, b and the apparent radius of the chain cross-section, R c are given

  11. Small-angle neutron scattering study of high-pressure sintered detonation nanodiamonds

    Energy Technology Data Exchange (ETDEWEB)

    Kidalov, S. V.; Shakhov, F. M., E-mail: fedor.shakhov@mail.ioffe.ru [Ioffe Physical-Technical Institute of the Russian Academy of Sciences (Russian Federation); Lebedev, V. T.; Orlova, D. N.; Grushko, Yu. S. [Russian Academy of Sciences, Konstantinov St. Petersburg Nuclear Physics Institute (Russian Federation)

    2011-12-15

    The structure of detonation diamonds sintered at a high pressure (7 GPa) and temperatures of 1200-1700 Degree-Sign C has been investigated by small-angle neutron scattering. It is shown that sintering leads to an increase in the particle size from 6 to 30 nm and established that this increase is due to the chainlike oriented attachment of particles. This study supplements the oriented-attachment model, which was suggested based on the X-ray diffraction spectra of detonation nanodiamonds (DNDs) sintered under the same conditions.

  12. Neutron scattering study of the phase transformation of LaNi3 induced by hydriding

    International Nuclear Information System (INIS)

    Ruan Jinghui; Zeng Xiangxin; Niu Shiwen

    1994-01-01

    The phase transformation of LaNi 3 induced by hydriding and de-hydriding is investigated using the neutron diffraction and the neutron inelastic scattering. The results show that the hydriding sample, LaNi 3 H x , is transformed from crystalline state of the LaNi 3 into amorphous state with a microcrystalline characteristic of LaNi 5 , and the de-hydriding sample produced by LaNi 3 H x dehydrated at 600 degree C is decomposed into new crystalline states composed by LaNi 5 -and La-hydrides. The procedure of phase transformation is that the result of the transformation of LaNi 3 induced by hydriding shows the properties of LaNi 5 -H 2 system

  13. Feasibility study for a first observation of coherent neutrino nucleus scattering using low-temperature detectors

    International Nuclear Information System (INIS)

    Guetlein, Achim

    2013-01-01

    Coherent Neutrino Nucleus Scattering (CNNS) is a neutral current process of the weak interaction. For low transferred momenta the neutrino scatters coherently off all nucleons leading to an enhanced cross section. However, because of the small resulting recoil energies (O(keV)) CNNS has not been observed experimentally so far. For the first observation of CNNS a strong neutrino source is needed. Thus, the expected count rates for solar neutrinos, supernova neutrinos, neutrinos generated by the decay of stopped π + particles at accelerators, and reactor neutrinos were calculated. Although an observation of CNNS could also be possible with other sources, the most promising neutrino sources are nuclear reactors with thermal powers between 2 and 4 GW. For an assumed energy threshold of 0.5 keV the target material with the largest count rate (∝10 kg -1 day -1 ) is sapphire. Thus, a low-temperature detector based on a 32 g sapphire crystal was designed and built to measure the background spectrum for energies below ∝10 keV. Although the energy threshold (∝1 keV) of this detector is too large for an observation of CNNS, the measured background spectrum can still be used for an investigation of the main background sources and the suppression of their events. For this investigation the simulated spectra of cosmic muons, ambient neutrons, and external gamma-rays are compared to the measured background spectrum. As a result, cosmic muons are the main contribution to the measured background spectrum. For a future experiment aiming at the observation of CNNS an array of 125 low-temperature detectors based on 32 g sapphire crystals is assumed. Background simulations of cosmic muons, ambient neutrons, and intrinsic radioactivity show that especially an efficient muon-veto system is crucial for a sufficient background suppression. To study the observation potential of this future experiment a distance of ∝ 40 m to a reactor core with a thermal power of ∝4 GW (neutrino

  14. Neutrons for Catalysis: A Workshop on Neutron Scattering Techniques for Studies in Catalysis

    International Nuclear Information System (INIS)

    Overbury, Steven H.; Coates, Leighton; Herwig, Kenneth W.; Kidder, Michelle

    2011-01-01

    This report summarizes the Workshop on Neutron Scattering Techniques for Studies in Catalysis, held at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) on September 16 and 17, 2010. The goal of the Workshop was to bring experts in heterogeneous catalysis and biocatalysis together with neutron scattering experimenters to identify ways to attack new problems, especially Grand Challenge problems in catalysis, using neutron scattering. The Workshop locale was motivated by the neutron capabilities at ORNL, including the High Flux Isotope Reactor (HFIR) and the new and developing instrumentation at the SNS. Approximately 90 researchers met for 1 1/2 days with oral presentations and breakout sessions. Oral presentations were divided into five topical sessions aimed at a discussion of Grand Challenge problems in catalysis, dynamics studies, structure characterization, biocatalysis, and computational methods. Eleven internationally known invited experts spoke in these sessions. The Workshop was intended both to educate catalyst experts about the methods and possibilities of neutron methods and to educate the neutron community about the methods and scientific challenges in catalysis. Above all, it was intended to inspire new research ideas among the attendees. All attendees were asked to participate in one or more of three breakout sessions to share ideas and propose new experiments that could be performed using the ORNL neutron facilities. The Workshop was expected to lead to proposals for beam time at either the HFIR or the SNS; therefore, it was expected that each breakout session would identify a few experiments or proof-of-principle experiments and a leader who would pursue a proposal after the Workshop. Also, a refereed review article will be submitted to a prominent journal to present research and ideas illustrating the benefits and possibilities of neutron methods for catalysis research.

  15. Neutrons for Catalysis: A Workshop on Neutron Scattering Techniques for Studies in Catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Overbury, Steven {Steve} H [ORNL; Coates, Leighton [ORNL; Herwig, Kenneth W [ORNL; Kidder, Michelle [ORNL

    2011-10-01

    This report summarizes the Workshop on Neutron Scattering Techniques for Studies in Catalysis, held at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) on September 16 and 17, 2010. The goal of the Workshop was to bring experts in heterogeneous catalysis and biocatalysis together with neutron scattering experimenters to identify ways to attack new problems, especially Grand Challenge problems in catalysis, using neutron scattering. The Workshop locale was motivated by the neutron capabilities at ORNL, including the High Flux Isotope Reactor (HFIR) and the new and developing instrumentation at the SNS. Approximately 90 researchers met for 1 1/2 days with oral presentations and breakout sessions. Oral presentations were divided into five topical sessions aimed at a discussion of Grand Challenge problems in catalysis, dynamics studies, structure characterization, biocatalysis, and computational methods. Eleven internationally known invited experts spoke in these sessions. The Workshop was intended both to educate catalyst experts about the methods and possibilities of neutron methods and to educate the neutron community about the methods and scientific challenges in catalysis. Above all, it was intended to inspire new research ideas among the attendees. All attendees were asked to participate in one or more of three breakout sessions to share ideas and propose new experiments that could be performed using the ORNL neutron facilities. The Workshop was expected to lead to proposals for beam time at either the HFIR or the SNS; therefore, it was expected that each breakout session would identify a few experiments or proof-of-principle experiments and a leader who would pursue a proposal after the Workshop. Also, a refereed review article will be submitted to a prominent journal to present research and ideas illustrating the benefits and possibilities of neutron methods for catalysis research.

  16. Fast diffusion in the intermetallics Ni3Sb and Fe3Si: a neutron scattering study

    International Nuclear Information System (INIS)

    Randl, O.G.

    1994-02-01

    We present the results of neutron scattering experiments designed to elucidate the reason for the extraordinarily fast majority component diffusion in two intermetallic alloys of DO 3 structure, Fe 3 Si and Ni 3 Sb: We have performed diffraction measurements in order to determine the crystal structure and the state of order of both alloys as a function of composition and temperature. The results on Fe 3 Si essentially confirm the classical phase diagram: The alloys of a composition between 16 and 25 at % Si are DO 3 -ordered at room temperature and disorder at high temperatures. The high-temperature phase Ni 3 Sb also crystallizes in the DO 3 structure. Vacancies are created in one Ni sublattice at Sb contents beyond 25 at %. In a second step the diffusion mechanism in Ni 3 Sb has been studied by means of quasielastic neutron scattering. The results are reconcileable with a very simple NN jump model between the two different Ni sublattices. Finally, the lattice dynamics of Fe 3 Si and Ni 3 Sb has been studied by inelastic neutron scattering in dependence of temperature (both alloys) and alloy composition (Fe 3 Si only). The results on Fe 3 Si indicate clearly that phonon enhancement is not the main reason for fast diffusion in this alloy. In Ni 3 Sb no typical signs of phonon-enhanced diffusion have been found either. As a conclusion, fast diffusion in DO 3 intermetallics is explained by extraordinarily high vacancy concentrations (several atomic percent) in the majority component sublattices. (author)

  17. Small angle neutron scattering studies of the flux line lattices in the borocarbide superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Eskildsen, Morten Ring

    1998-12-01

    This thesis describes small angle neutron scattering studies of the flux line lattice (FLL) in the following members of the borocarbide superconductors: YNi{sub 2}B{sub 2}C, ErNi{sub 2}B{sub 2}C, TmNi{sub 2}B{sub 2}C, LuNi{sub 2}B{sub 2}C, Y{sub 0.75}Lu{sub 0.25}Ni{sub 2}B{sub 2}C and Lu(Ni{sub 1-x}CO{sub x}){sub 2}B{sub 2}C with x = 1.5 - 9%. Of the materials ErN{sub 2}B{sub 2}C and TmNi{sub 2}B{sub 2}C exhibits coexisting superconductivity and magnetic ordering. Three main conclusions can be derived from the results in this thesis. Existence of a low field hexagonal to square symmetry transition of the FLL, ubiquitous to the superconducting borocarbides, magnetic and non-magnetic alike. This symmetry transition is due to the four-fold anisotropy of the Fermi surface, distorting the screening currents towards a square flow pattern. This four-fold anisotropy together with non-local electrodynamics induces a transition to a square FLL, as the field is increased. Changing the non-locality range shifts the square to hexagonal transition onset field. A static disordering of the FLL in YNi{sub 2}B{sub 2}C and LuNi{sub 2}B{sub 2}C. In these materials one observes a well ordered FLL, with a longitudinal correlation length exceeding 100 flux line spacings. As the applied field is increased the longitudinal correlation length, increases with field up to H/H{sub c2} {approx} 0.2. Above this field the FLL correlation length slowly starts to fall off, in contradiction to theoretical models. The existence of complex interactions between the magnetic state and the FLL in TmNi{sub 2}B{sub 2}C. This is signalled by coinciding changes in the FLL symmetry and in the magnetic structure. The FLL show a two-step symmetry transition from square to rhombic and then hexagonal with increased field. In addition, the FLL reflectivity shows distinct peaks as the thulium ions orders magnetically at T{sub N} and across the field driven magnetic transition. No explanation for this behaviour

  18. Small angle neutron scattering studies of the flux line lattices in the borocarbide superconductors

    International Nuclear Information System (INIS)

    Eskildsen, Morten Ring

    1998-12-01

    This thesis describes small angle neutron scattering studies of the flux line lattice (FLL) in the following members of the borocarbide superconductors: YNi 2 B 2 C, ErNi 2 B 2 C, TmNi 2 B 2 C, LuNi 2 B 2 C, Y 0.75 Lu 0.25 Ni 2 B 2 C and Lu(Ni 1-x CO x ) 2 B 2 C with x = 1.5 - 9%. Of the materials ErN 2 B 2 C and TmNi 2 B 2 C exhibits coexisting superconductivity and magnetic ordering. Three main conclusions can be derived from the results in this thesis. Existence of a low field hexagonal to square symmetry transition of the FLL, ubiquitous to the superconducting borocarbides, magnetic and non-magnetic alike. This symmetry transition is due to the four-fold anisotropy of the Fermi surface, distorting the screening currents towards a square flow pattern. This four-fold anisotropy together with non-local electrodynamics induces a transition to a square FLL, as the field is increased. Changing the non-locality range shifts the square to hexagonal transition onset field. A static disordering of the FLL in YNi 2 B 2 C and LuNi 2 B 2 C. In these materials one observes a well ordered FLL, with a longitudinal correlation length exceeding 100 flux line spacings. As the applied field is increased the longitudinal correlation length, increases with field up to H/H c2 ∼ 0.2. Above this field the FLL correlation length slowly starts to fall off, in contradiction to theoretical models. The existence of complex interactions between the magnetic state and the FLL in TmNi 2 B 2 C. This is signalled by coinciding changes in the FLL symmetry and in the magnetic structure. The FLL show a two-step symmetry transition from square to rhombic and then hexagonal with increased field. In addition, the FLL reflectivity shows distinct peaks as the thulium ions orders magnetically at T N and across the field driven magnetic transition. No explanation for this behaviour exists at the present. (au)

  19. Studies on silica sol-clay particle interactions by small-angle neutron scattering

    International Nuclear Information System (INIS)

    Moini, A.; Pinnavaia, T.J.; Michigan State Univ., East Lansing; Thiyagarajan, P.; White, J.W.

    1988-01-01

    SANS data were collected on a series of hydrolyzed silica and silica-clay complexes prepared from a 40 A silica sol and aqueous suspensions of Na + montmorillonite. The hydrolyzed silica product showed a peak centered at Q=0.0856 A -1 corresponding to a distance of 73 A between the sol particles. For such an evaporated gel in which the particles are in close contact, this distance is expected to be very close to the particle diameter indicating partial aggregation of the original spheres. A similar feature was observed in the SANS data for silica-clay products indicating the presence of some unintercalated silica. The intensity of this scattering was found to be dependent on the silica:clay ratio and the reaction time. The SANS data in the region from Q=0.006 to 0.025 A -1 were characteristic of clay scattering and exhibited a power-law behavior. The change in the slope of this curve upon reaction of the clay with the silica sol was interpreted in terms of a separation of clay platelets caused by a binding interaction with the sol particles. (orig.)

  20. Hydrogen adsorption in HKUST-1: a combined inelastic neutron scattering and first-principles study

    International Nuclear Information System (INIS)

    Brown, Craig M; Liu Yun; Yildirim, Taner; Peterson, Vanessa K; Kepert, Cameron J

    2009-01-01

    Hydrogen adsorption in high surface area nanoporous coordination polymers has attracted a great deal of interest in recent years due to the potential applications in energy storage. Here we present combined inelastic neutron scattering measurements and detailed first-principles calculations aimed at unraveling the nature of hydrogen adsorption in HKUST-1 (Cu 3 (1,3,5-benzenetricarboxylate) 2 ), a metal-organic framework (MOF) with unsaturated metal centers. We reveal that, in this system, the major contribution to the overall binding comes from the classical Coulomb interaction which is not screened due to the open metal site; this explains the relatively high binding energies and short H 2 -metal distances observed in MOFs with exposed metal sites as compared to traditional ones. Despite the short distances, there is no indication of an elongation of the H-H bond for the bound H 2 molecule at the metal site. We find that both the phonon and rotational energy levels of the hydrogen molecule are closely similar, making the interpretation of the inelastic neutron scattering data difficult. Finally, we show that the orientation of H 2 has a surprisingly large effect on the binding potential, reducing the classical binding energy by almost 30%. The implication of these results for the development of MOF materials for better hydrogen storage is discussed.