WorldWideScience

Sample records for brillouin scattering study

  1. Brillouin scattering at high pressures

    International Nuclear Information System (INIS)

    Grimsditch, M.; Polian, A.

    1988-02-01

    Technical advances which have made Brillouin scattering a useful tool in high pressure diamond anvil cell (DAC) studies, viz. multipassing and tandem operation of Fabry-Perot interferometers, are reviewed. Experimental aspects, such as allowed scattering geometries, are outlined and the data analysis required to transform Brillouin spectra into sound velocities and elastic constants is presented. Experimental results on H 2 , N 2 , Ar, and He are presented, and the close relationship between the Brillouin scattering results and equations of state is highlighted

  2. Shear Brillouin light scattering microscope.

    Science.gov (United States)

    Kim, Moonseok; Besner, Sebastien; Ramier, Antoine; Kwok, Sheldon J J; An, Jeesoo; Scarcelli, Giuliano; Yun, Seok Hyun

    2016-01-11

    Brillouin spectroscopy has been used to characterize shear acoustic phonons in materials. However, conventional instruments had slow acquisition times over 10 min per 1 mW of input optical power, and they required two objective lenses to form a 90° scattering geometry necessary for polarization coupling by shear phonons. Here, we demonstrate a confocal Brillouin microscope capable of detecting both shear and longitudinal phonons with improved speeds and with a single objective lens. Brillouin scattering spectra were measured from polycarbonate, fused quartz, and borosilicate in 1-10 s at an optical power level of 10 mW. The elastic constants, phonon mean free path and the ratio of the Pockels coefficients were determined at microscopic resolution.

  3. Stimulated Brillouin scattering experiments

    International Nuclear Information System (INIS)

    Slater, D.C.; Berger, R.L.; Busch, G.; Kinzer, C.M.; Mayer, F.J.; Powers, L.V.; Tanner, D.J.

    1981-01-01

    This report describes two experiments in which SBS would be expected to play an important role. In the first experiment, we find a clear signature of the Brillouin backscatter of a short (100 psec) pulse from a long (approx. 50 μm) gradient length gas target plasma. The second experiment used much longer (approx. 1 nsec) pulses on spherical glass shell targets. These experiments were done with both narrow ( 30A) bandwidth laser light. Using one-dimensional, spherically symmetric fluid simulations, we have attempted to model many of the laser-plasma interaction processes which combine to determine the amount of absorbed energy in the long-pulse experiments. These simulations indicate that modest laser bandwidths are successful in reducing the level of SBS at the irradiances ( 15 W/cm 2 ) used in these experiments

  4. Transient effects on stimulated Brillouin scattering

    International Nuclear Information System (INIS)

    Faris, G.W.; Dyer, M.J.; Hickman, A.P.

    1992-01-01

    We present a detailed comparison of theory and experiment for transient stimulated Brillouin scattering for a pump pulse with Gaussian temporal profile. A new approach for measuring Brillouin linewidths is demonstrated, and an unexplained asymmetry is observed

  5. Nonlinear Fluid Simulation Study of Stimulated Raman and Brillouin Scatterings in Shock Ignition

    Science.gov (United States)

    Ren, Chuang; Hao, Liang; Yan, Rui; Li, Jun; Liu, Wenda

    2017-10-01

    We developed a new nonlinear fluid laser-plasma-instability code FLAME using a multi-fluid plasma model combined with full electromagnetic wave equations. The completed one-dimensional (1D) version of FLAME was used to study laser-plasma instabilities in shock ignition. The simulations results showed that absolute Stimulated Raman Scattering (SRS) modes growing near the quarter-critical surface were saturated by Langmuir-wave Decay Instabilities (LDI) and pump depletion. The ion-acoustic waves from LDI acted as seeds of Stimulated Brillouin Scattering (SBS), which displayed a bursting pattern and caused strong pump depletion. Re-scattering of SRS was also observed in a high temperature case. These results largely agreed with corresponding Particle-in-Cell simulations. Work funded by DOE (DE-SC0012316), NSF (PHY-1314734), NSFC (11642020, 11621202), and Science Challenge Project (No. JCKY2016212A505).

  6. Angle-resolved spin wave band diagrams of square antidot lattices studied by Brillouin light scattering

    Energy Technology Data Exchange (ETDEWEB)

    Gubbiotti, G.; Tacchi, S. [Istituto Officina dei Materiali del Consiglio Nazionale delle Ricerche (IOM-CNR), Sede di Perugia, c/o Dipartimento di Fisica e Geologia, Via A. Pascoli, I-06123 Perugia (Italy); Montoncello, F.; Giovannini, L. [Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, Via G. Saragat 1, I-44122 Ferrara (Italy); Madami, M.; Carlotti, G. [Dipartimento di Fisica e Geologia, Università di Perugia, Via A. Pascoli, I-06123 Perugia (Italy); Ding, J.; Adeyeye, A. O. [Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore)

    2015-06-29

    The Brillouin light scattering technique has been exploited to study the angle-resolved spin wave band diagrams of squared Permalloy antidot lattice. Frequency dispersion of spin waves has been measured for a set of fixed wave vector magnitudes, while varying the wave vector in-plane orientation with respect to the applied magnetic field. The magnonic band gap between the two most dispersive modes exhibits a minimum value at an angular position, which exclusively depends on the product between the selected wave vector magnitude and the lattice constant of the array. The experimental data are in very good agreement with predictions obtained by dynamical matrix method calculations. The presented results are relevant for magnonic devices where the antidot lattice, acting as a diffraction grating, is exploited to achieve multidirectional spin wave emission.

  7. Brillouin scattering: its application to the study of damage and amorphization

    International Nuclear Information System (INIS)

    Grimsditch, M.; Bhadra, R.; Gray, K.; Kampwirth, R.T.; Okamoto, P.; Pearson, J.; Rehn, L.

    1988-02-01

    A brief review of Brillouin scattering is made emphasizing its advantages and disadvantages over conventional ultrasonic techniques. One of its advantages is that the elastic properties of very thin films (∼ 1μ) can be investigated. The authors have used this technique to study changes in shear elastic constants of materials irradiated with high energy ions. These particles only penetrate ∼ 1μ into the material but produce very high defect concentrations which, in certain cases, can lead to amorphization. In Nb 3 Ir and Zr 3 Al very large changes are observed before the onset of amorphization, while in Si the changes occur concomitantly with amorphization. The significance of the hardening observed in Zr 3 Al when it becomes amorphous will be discussed

  8. Thomson-scattering study of the subharmonic decay of ion-acoustic waves driven by the Brillouin instability

    International Nuclear Information System (INIS)

    Bandulet, H.C.; Labaune, C.; Lewis, K.; Depierreux, S.

    2004-01-01

    Thomson scattering (TS) has been used to investigate the two-ion decay instability of ion acoustic waves generated by stimulated Brillouin scattering in an underdense CH plasma. Two complementary TS diagnostics, spectrally and spatially resolved, demonstrate the occurrence of the subharmonic decay of the primary ion acoustic wave into two secondary waves. The study of the laser intensity dependence shows that the secondary ion acoustic waves are correlated with the SBS reflectivity saturation, at a level of a few percent

  9. High temperature surface Brillouin scattering study of mechanical properties of boron-doped epitaxial polysilicon

    Directory of Open Access Journals (Sweden)

    B. A. Mathe

    2017-02-01

    Full Text Available A study of the mechanical properties of a boron-doped epitaxial polysilicon layer deposited on a Si (100 substrate specimen has been carried out by surface Brillouin scattering at high temperatures. This type of specimen is widely used in micro-electro-mechanical systems (MEMS. By accumulating spectra with the Rayleigh mode and the Lamb continuum the isotropic elastic constants C44 and C11 were obtained, from which the values of the bulk, shear and Young’s moduli and Poisson’s ratio for the layer were determined over a range of temperatures from 20 °C to 110 °C. By contrast, an examination of the literature on polycrystalline silicon shows that other methods each provide a limited range of the above properties and thus additional experiments and techniques were needed. The SBS method is applicable to other polycrystalline materials such as silicon carbide, silicon nitride, silicon germanium and amorphous diamond that have also been used for MEMS applications.

  10. Analytical study of nonlinear phase shift through stimulated Brillouin scattering in single mode fiber with the pump power recycling technique

    International Nuclear Information System (INIS)

    Al-Asadi, H A; Mahdi, M A; Bakar, A A A; Adikan, F R Mahamd

    2011-01-01

    We present a theoretical study of nonlinear phase shift through stimulated Brillouin scattering in single mode optical fiber. Analytical expressions describing the nonlinear phase shift for the pump and Stokes waves in the pump power recycling technique have been derived. The dependence of the nonlinear phase shift on the optical fiber length, the reflectivity of the optical mirror and the frequency detuning coefficient have been analyzed for different input pump power values. We found that with the recycling pump technique, the nonlinear phase shift due to stimulated Brillouin scattering reduced to less than 0.1 rad for 5 km optical fiber length and 0.65 reflectivity of the optical mirror, respectively, at an input pump power equal to 30 mW

  11. Neutron Brillouin scattering in dense fluids

    Energy Technology Data Exchange (ETDEWEB)

    Verkerk, P. [Technische Univ. Delft (Netherlands); FINGO Collaboration

    1997-04-01

    Thermal neutron scattering is a typical microscopic probe for investigating dynamics and structure in condensed matter. In contrast, light (Brillouin) scattering with its three orders of magnitude larger wavelength is a typical macroscopic probe. In a series of experiments using the improved small-angle facility of IN5 a significant step forward is made towards reducing the gap between the two. For the first time the transition from the conventional single line in the neutron spectrum scattered by a fluid to the Rayleigh-Brillouin triplet known from light-scattering experiments is clearly and unambiguously observed in the raw neutron data without applying any corrections. Results of these experiments are presented. (author).

  12. The Measurement of Tropospheric Temperature Profiles using Rayleigh-Brillouin Scattering : Results from Laboratory and Atmospheric Studies

    NARCIS (Netherlands)

    Witschas, Benjamin; Reitebuch, Oliver; Lemmerz, Christian; Kableka, Pau Gomez; Kondratyev, Sergey; Gu, Z.; Ubachs, Wim

    2016-01-01

    In this letter, we suggest a new method for measuring tropospheric temperature profiles using Rayleigh-Brillouin (RB) scattering. We report on laboratory RB scattering measurements in air, demonstrating that temperature can be retrieved from RB spectra with an absolute accuracy of better than 2 K.

  13. A Brillouin scattering study of the effect of chemical passivation on the elastic properties of porous silicon

    Science.gov (United States)

    Fan, H. J.; Kuok, M. H.; Ng, S. C.; Boukherroub, R.; Lockwood, D. J.

    2002-07-01

    Brillouin scattering has been performed to probe acoustic waves in porous silicon films that have been chemically modified with either 1-decene, decyl aldehyde, undecylenic acid, or ethyl undecylenate. The shift in the frequencies of acoustic modes in the passivated porous silicon samples, relative to those in freshly prepared porous silicon, is different for different chemical modifiers. The magnitude of the frequency shift is qualitatively correlated with the change, caused by the passivation, in the average densities and elastic constants of the samples.

  14. Brillouin scattering study of surface acoustic waves in crystalline GaP

    Science.gov (United States)

    Zuk, J.; Kiefte, H.; Clouter, M. J.

    1992-10-01

    Surface acoustic modes in GaP crystals have been observed and identified using the technique of high-contrast Brillouin spectroscopy. Surface acoustic wave velocities were determined for (100) GaP in different directions of wave propagation. The values of the velocities are: 3250 m/s in the [010] direction and 3467 m/s in the [011] direction on the (100) GaP surface. These results are discussed and compared with theoretical calculations and with similar measurements in GaAs and Si.

  15. Elastic properties of aspirin in its crystalline and glassy phases studied by micro-Brillouin scattering

    Science.gov (United States)

    Ko, Jae-Hyeon; Lee, Kwang-Sei; Ike, Yuji; Kojima, Seiji

    2008-11-01

    The acoustic waves propagating along the direction perpendicular to the (1 0 0) cleavage plane of aspirin crystal were investigated using micro-Brillouin spectroscopy from which C11, C55 and C66 were obtained. The temperature dependence of the longitudinal acoustic waves could be explained by normal anharmonic lattice models, while the transverse acoustic waves showed an abnormal increase in the hypersonic attenuation at low temperatures indicating their coupling to local remnant dynamics. The sound velocity as well as the attenuation of the longitudinal acoustic waves of glassy aspirin showed a substantial change at ˜235 K confirming a transition from glassy to supercooled liquid state in vitreous aspirin.

  16. Linear approximation of Rayleigh-Brillouin scattering spectra.

    Science.gov (United States)

    Binietoglou, Ioannis; Giampouras, Paris; Belegante, Livio

    2016-09-20

    Rayleigh-Brillouin scattering is the basis of many remote sensing techniques, including high spectral resolution lidar measurements of aerosols and wind. Rayleigh-Brillouin spectra can be accurately estimated using physics-based models like the so-called Tenti's S6 and Pan's S7 models. Unfortunately, these are computationally expensive and can be the bottleneck for real-time lidar processing and iterative parameter estimation problems. This short article describes a very efficient linear approximation of the Rayleigh-Brillouin spectra based on Principal Component Analysis (PCA). Using PCA, the outputs of the above models can be approximated with very high accuracy using a single matrix multiplication. The described method can be applied to the output of any detailed scattering model, thus it can be used for a wide range of problems, e.g., for scattering from different gases (Air, N2, O2,…) and for different ranges of temperature and pressure. The precision of the approximation can be adapted to the requirements of the studied problem, and can easily exceed the actual accuracy of the reference models.

  17. Discrete modes of a ferromagnetic stripe dipolarly coupled to a ferromagnetic film: a Brillouin light scattering study

    International Nuclear Information System (INIS)

    Gubbiotti, G; Tacchi, S; Carlotti, G; Ono, T; Roussigne, Y; Tiberkevich, V S; Slavin, A N

    2007-01-01

    Spin wave excitations in a magnetic structure consisting of a series of long permalloy stripes of a rectangular cross section magnetized along the stripe length and situated above a continuous permalloy film are studied both experimentally and theoretically. Stripes and continuous film are coupled by dipole-dipole interaction across 10 nm thick Cu spacers. Experimental measurements made using the Brillouin light scattering technique (with the light wavevector oriented along the stripe width) provide evidence for one dispersive spin wave mode associated with the continuous film and several discrete non-dispersive modes resonating within the finite width of the stripes. To interpret the experimental spectra, an analytic theory based on the spin wave formalism for finite-width magnetic stripes has been developed, achieving a good qualitative and partly quantitative description of the experimentally observed spin wave spectrum of the system. In particular, it is explained why the presence of a continuous magnetic film near the magnetic stripe leads to a substantial decrease of the frequencies of the discrete dipolar spin wave modes localized within the stripes. A more quantitative description of the measured frequencies and of the spatial profiles of the spin wave eigenmodes has been obtained by numerical calculations performed using a finite element method

  18. Influence of KF substitution on the ferroelectric phase transition of lead titanate single crystals studied by Brillouin light scattering

    Directory of Open Access Journals (Sweden)

    Seonhyeop Shin

    2015-06-01

    Full Text Available The elastic properties of KF-substituted perovskite lead titanate (PbTiO3 were investigated by dielectric measurements and Brillouin light scattering. The ferroelectric phase transition occurred at substantially lower temperature due to KF substitution, which was attributed to the modification of the covalency in Pb–O and Ti–O bonds. The longitudinal acoustic (LA mode of KF-substituted PbTiO3 showed a frequency softening in the paraelectric phase, which was accompanied by increasing acoustic damping. This indicated that polarization fluctuations responsible for the acoustic anomalies were enhanced by KF substitution.

  19. Martensitic phase transition in Cu–14%Al–4%Ni shape memory alloys studied by Brillouin light scattering

    International Nuclear Information System (INIS)

    Graczykowski, B; Mielcarek, S; Mroz, B; Breczewski, T; No, M L; San-Juan, J

    2013-01-01

    The paper presents the influence of the martensitic phase transition on hypersonic thermally excited surface acoustic waves propagating in Cu–14%Al–4%Ni (wt%) shape memory alloy. Non-destructive and non-contact testing using Brillouin light scattering spectroscopy permitted determination of the elastic constants of austenite versus temperature. Experimental results obtained for martensite were interpreted using the proposed model of the cubic to orthorhombic martensitic phase transition based on the Landau model of a first-order phase transition. Additionally we adopted the approximation of the domain structure of martensite by a polycrystalline sample using the Voigt–Reuss–Hill procedure of averaging the elastic constants. (paper)

  20. Stimulated Brillouin scattering materials, experimental design and applications: A review

    Science.gov (United States)

    Bai, Zhenxu; Yuan, Hang; Liu, Zhaohong; Xu, Pengbai; Gao, Qilin; Williams, Robert J.; Kitzler, Ondrej; Mildren, Richard P.; Wang, Yulei; Lu, Zhiwei

    2018-01-01

    Stimulated Brillouin scattering (SBS), as one type of third-order nonlinear optics effect, is extensively exploited and rapidly developed in the field of lasers and optoelectronics. A large number of theoretical and experimental studies on SBS have been carried out in the past decades. Especially, the exploration of new SBS materials and new types of SBS modulation methods have been engaged simultaneously, as the properties of different materials have great influence on the SBS performance such as generation threshold, Brillouin amplification efficiency, frequency shift, breakdown threshold, etc. This article provides a comprehensive review of the characteristics of different types of SBS materials, SBS applications, experimental design methods, as well as the parameter optimization method, which is expected to provide reference and guidance to SBS related experiments.

  1. Stimulated Brillouin scattering in long-scale-length laser plasmas

    International Nuclear Information System (INIS)

    Chirokikh, A.; Seka, W.; Simon, A.; Craxton, R.S.; Tikhonchuk, V.T.

    1998-01-01

    Brillouin scattering from a preformed, inhomogeneous, expanding plasma has been investigated. Backscattered light near the incident laser wavelength (λ=1054 nm) from CH planar targets has been spectrally and temporally resolved. By varying the time delay of the interaction beam, the scattering was studied for different plasma conditions. The backscattered light is predominantly blue-shifted and appears before the peak of the laser pulse. The experimental time-integrated reflectivity of backscattered light is in the range of 1%endash 10% and decreases with the plasma density. The time-resolved spectra and total reflectivity were calculated using a theory of convective stimulated Brillouin scattering (SBS) in a flowing inhomogeneous plasma combined with a statistical hot spot model for the interaction beam. The plasma parameters for these calculations were provided by simulations using a two-dimensional hydrodynamic code. The calculated SBS spectra are similar to the experimental observations. The time-integrated reflectivities agree well with the experimental results for the higher peak density interactions, but are below the observations by orders of magnitude for the lowest peak density cases. copyright 1998 American Institute of Physics

  2. Limitation of brillouin scatter in plasmas

    International Nuclear Information System (INIS)

    Kruer, W.L.; Valeo, E.J.; Estabrook, K.G.

    1975-01-01

    A simple model is proposed for the limitation of Brillouin backscatter often observed experimentally. This limitation is a natural consequence of the limited mass and heat capacity of the underdense plasma. In this model a reflection front moves through the underdense plasma supersonically. For plasmas prepared by a prepulse, the reflectivity could then be time-dependent in agreement with some recent experimental measurements. (U.S.)

  3. Localized spin-wave modes in a triangular magnetic element studied by micro-focused Brillouin light scattering

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, S.; Kwon, J.-H. [School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of); Grünberg, P. [Grünberg Center for Magnetic Nanomaterials, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of); Cho, B.K., E-mail: chobk@gist.ac.kr [School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of)

    2017-09-01

    Highlights: • Direct evidence of localized mode in a triangular nano-magnet using μ-BLS. • Localized regions are identified by the internal field distribution. • The spatially resolved measurement was performed to obtain 2-D intensity map. • Spin modes in same positions can be distinguish comparing with simulated spectrum. • Localized modes were identified by comparing with the simulated spatial profiles. - Abstract: Localized spin-wave modes, which were thermally excited at a specific position in a triangular magnetic element, were investigated using micro-focused Brillouin light scattering in two saturated states, the buckle and Y-states, with an applied magnetic field of 0.24 T parallel and perpendicular to the basal edge, respectively. The measured frequency spectrum at a specific beam spot position, rather than an integrated spectrum, was analyzed by comparing it with the simulation data at a precisely selected position within the beam spot area. The analyzed results were used to plot a two-dimensional intensity map and simulation spatial profile to verify the validity of the analysis. From the analysis process, two localized spin-wave modes in a triangular magnetic element were successfully identified near the apex region in the buckle state and near the basal edge region in the Y-state.

  4. Brillouin scattering, DSC, dielectric and X-ray diffraction studies of phase transitions in antiferroelectric PbHfO{sub 3}:Sn

    Energy Technology Data Exchange (ETDEWEB)

    Mączka, Mirosław, E-mail: m.maczka@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław 2 (Poland); Kim, Tae Hyun [Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Gągor, Anna [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wrocław 2 (Poland); Jankowska-Sumara, Irena [Institute of Physics, Pedagogical University, ul. Podchorążych 2, 30-084 Kraków (Poland); Majchrowski, Andrzej [Institute of Applied Physics, Military University of Technology, 2 Kaliskiego Str., 00-908 Warszawa (Poland); Kojima, Seiji [Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)

    2015-02-15

    Highlights: • Phase transition mechanisms were studied in antiferroelectric PbHf{sub 0.975}Sn{sub 0.025}O{sub 3.} • Acoustic phonons showed anomalies at 472 and 426 K due to phase transitions. • Brillouin data showed evidence for presence of polar clusters in paraelectric phase. • An order-disorder mechanism of the PE to AFE2 transition was proved. - Abstract: Specific heat, dielectric, powder X-ray diffraction and Brillouin scattering studies of phase transitions in antiferroelectric PbHf{sub 0.975}Sn{sub 0.025}O{sub 3} crystal were performed. The specific heat data revealed clear anomalies at T{sub 1} = 473.5 and T{sub 2} = 426.3 K on cooling, which could be attributed to onset of first order phase transitions from the paraelectric (PE) phase to an intermediate antiferroelectric phase (AFE2) and the AFE2 phase to another antiferroelectric phase (AFE1), respectively. The estimated entropy changes at T{sub 1} and T{sub 2} pointed to mainly an order-disorder and displacive character of these transitions, respectively. X-ray diffraction data showed a complex superstructure of the intermediate phase with a = 11.895(6) Å, b = 11.936(4) Å, c = 8.223(3) Å at 453 K. Brillouin studies revealed pronounced softening of longitudinal acoustic (LA) mode in the PE phase associated with its broadening. The broadening and softening exhibited maximum values at T{sub 1}. Additional acoustic anomalies, that is, abrupt frequency shifts for LA and transverse acoustic (TA) modes were also observed at T{sub 2}. Brillouin scattering data also showed presence of a broad central peak (CP) that exhibited highest intensity at T{sub 1}. The observed temperature dependences of acoustic modes and CP indicate order-disorder character of the FE to AFE2 phase transition and importance of polar precursor clusters in the PE phase. The obtained data also suggest that the intermediate antiferroelectric phases in Sn{sup 4+} doped PbHfO{sub 3} and PbZrO{sub 3} may have very similar structures

  5. Electron Gyro-Harmonic Effects on Ionospheric Stimulated Brillouin Scatter

    Science.gov (United States)

    2014-08-21

    SECURITY CLASSIFICATION OF: Stimulated Brillouin scattering (SBS) and resonant phenomena are well known in the context of laser fusion, fiber optics ... fiber optics , and piezoelectric semiconductor plasmas, as well as in various biological applications. Due to recent advances, active space experiments... fiber optics , and piezoelectric semiconductor plasmas, as well as in various biological applications. Due to recent advances, active space

  6. High-speed stimulated Brillouin scattering spectroscopy at 780 nm

    Directory of Open Access Journals (Sweden)

    Itay Remer

    2016-09-01

    Full Text Available We demonstrate a high-speed stimulated Brillouin scattering (SBS spectroscopy system that is able to acquire stimulated Brillouin gain point-spectra in water samples and Intralipid tissue phantoms over 2 GHz within 10 ms and 100 ms, respectively, showing a 10-100 fold increase in acquisition rates over current frequency-domain SBS spectrometers. This improvement was accomplished by integrating an ultra-narrowband hot rubidium-85 vapor notch filter in a simplified frequency-domain SBS spectrometer comprising nearly counter-propagating continuous-wave pump-probe light at 780 nm and conventional single-modulation lock-in detection. The optical notch filter significantly suppressed stray pump light, enabling detection of stimulated Brillouin gain spectra with substantially improved acquisition times at adequate signal-to-noise ratios (∼25 dB in water samples and ∼15 dB in tissue phantoms. These results represent an important step towards the use of SBS spectroscopy for high-speed measurements of Brillouin gain resonances in scattering and non-scattering samples.

  7. A Brillouin scattering study of La0.77Ca0.23MnO3 across the metal-insulator transition

    International Nuclear Information System (INIS)

    Seikh, Md Motin; Narayana, Chandrabhas; Sudheendra, L; Sood, A K; Rao, C N R

    2004-01-01

    Temperature-dependent Brillouin scattering studies have been carried out on La 0.77 Ca 0.23 MnO 3 across the paramagnetic insulator-ferromagnetic metal (I-M) transition (T C ∼ 230 K). The spectra show modes corresponding to a surface Rayleigh wave (SRW) and a high velocity pseudo-surface wave (HVPSAW) along with bulk acoustic waves (B1 and B2). The Brillouin shifts associated with the SRW and HVPSAW increase, whereas the B1 and B2 frequencies decrease, below T C . The temperature dependence of the SRW and HVPSAW modes is related to the increase in the elastic constant C 11 across the I-M transition. The decrease in frequency across the I-M transition of the bulk modes is understood to be due to enhanced self-energy corrections as a result of increased magnon-phonon interaction across the I-M transition. Correspondingly, these modes show a large increase in the full width at half maximum (FWHM) as the temperature decreases. We also observe a central peak whose width is maximum at T C

  8. Extreme temperature sensing using brillouin scattering in optical fibers

    CERN Document Server

    Fellay, Alexandre

    Stimulated Brillouin scattering in silica-based optical fibers may be considered from two different and complementary standpoints. For a physicist, this interaction of light and pressure wave in a material, or equivalently in quantum theory terms between photons and phonons, gives some glimpses of the atomic structure of the solid and of its vibration modes. For an applied engineer, the same phenomenon may be put to good use as a sensing mechanism for distributed measurements, thanks to the dependence of the scattered light on external parameters such as the temperature, the pressure or the strain applied to the fiber. As far as temperature measurements are concerned, Brillouin-based distributed sensors have progressively gained wide recognition as efficient systems, even if their rather high cost still restricts the number of their applications. Yet they are generally used in a relatively narrow temperature range around the usual ambient temperature; in this domain, the frequency of the scattered light incre...

  9. Momentum transfer in a Brillouin surface scattering

    International Nuclear Information System (INIS)

    Khater, A.F.

    1980-01-01

    The theory of acoustic excitation scattering in the surface of Brilloiun of opaque materials, is related to the question of momentum transfexed from radiation fields to the material when the incident eight is scattered in a measurable spectrum. (A.C.A.S.) [pt

  10. SBS [stimulated Brillouin scattering] pulse distortion in multimode optical fibers

    International Nuclear Information System (INIS)

    Smith, J.R.; Hawkins, R.J.; Laumann, C.W.; Hatch, J.

    1989-01-01

    We have observed sever temporal-pulse-shape distortion due to stimulated Brillouin scattering (SBS) in multimode optical fibers used to diagnose 351 m laser pulses on the Nova laser system. Our measurements can be fit by a basic model of SBS and provide a clear indication of the intensity and temporal regimes where significant SBS-induced temporal-pulse-shape distortion can be avoided. 15 refs., 3 figs., 1 tab

  11. Stimulated Brillouin scattering of electromagnetic Alfven waves in a plasma

    International Nuclear Information System (INIS)

    Sharma, R.R.; Sharma, R.C.; Sharma, O.P.

    1981-01-01

    The phenomenon of stimulated Brillouin scattering of electromagnetic Alfven waves in a plasma is investigated by employing fluid model approach. The low frequency nonlinearity of ion acoustic wave arises through the ponderomotive force on ions and high frequency nonlinearity arises through the equation of continuity. For a typical isothermal plasma (Tsub(e)/Tsub(i)approx.=10), Alfven wave frequency ω 0 approx.=10 6 rad. sec -1 , the threshold for this instability in a uniform plasma is approx.= milliwatt cm -2 . Above the threshold, the growth rate for forward and back scatterings are approx.=10 -3 rad.sec -1 and approx.=10 -4 rad.sec. -1 , respectively. (author)

  12. High resolution Brillouin scattering studies of β-Gd2(MoO4)3; the bulk and surface phase transitions

    International Nuclear Information System (INIS)

    Mielcarek, S; Trzaskowska, A; Mroz, B; Andrews, T

    2005-01-01

    We present here results of Brillouin scattering from bulk and surface phonons propagating in a well known ferroelectric-ferroelastic crystal β-Gd 2 (MoO 4 ) 3 , in the temperature range covering the phase transition. Temperature dependences of the velocity of Rayleigh surface acoustic waves, propagating in a few planes of this crystal, have been calculated. The surface phonon velocities determined experimentally have been found to show a different character of temperature dependences, especially in the phase transition range

  13. High-pressure Brillouin scattering in a simple molecular system

    CERN Document Server

    Shimizu, H

    2002-01-01

    Recent developments in high-pressure in situ Brillouin spectroscopy of a simple molecular system are reviewed by demonstrating experimental and analytical methods for the study of acoustic velocities in any direction, adiabatic elastic constants, and elastic anisotropy. Detailed applications to solid argon (Ar) are presented, at pressures up to 70 GPa in a diamond anvil cell, using recently developed approaches that combine the method of in situ Brillouin spectroscopy, for a single crystal of Ar up to 4 GPa, and the envelope method applied to both longitudinal acoustic and transverse acoustic modes, for recrystallized Ar between 4 and 70 GPa.

  14. Guided acoustic and optical waves in silicon-on-insulator for Brillouin scattering and optomechanics

    Directory of Open Access Journals (Sweden)

    Christopher J. Sarabalis

    2016-10-01

    Full Text Available We numerically study silicon waveguides on silica showing that it is possible to simultaneously guide optical and acoustic waves in the technologically important silicon on insulator (SOI material system. Thin waveguides, or fins, exhibit geometrically softened mechanical modes at gigahertz frequencies with phase velocities below the Rayleigh velocity in glass, eliminating acoustic radiation losses. We propose slot waveguides on glass with telecom optical frequencies and strong radiation pressure forces resulting in Brillouin gains on the order of 500 and 50 000 W−1m−1 for backward and forward Brillouin scattering, respectively.

  15. Guided acoustic and optical waves in silicon-on-insulator for Brillouin scattering and optomechanics

    Science.gov (United States)

    Sarabalis, Christopher J.; Hill, Jeff T.; Safavi-Naeini, Amir H.

    2016-10-01

    We numerically study silicon waveguides on silica showing that it is possible to simultaneously guide optical and acoustic waves in the technologically important silicon on insulator (SOI) material system. Thin waveguides, or fins, exhibit geometrically softened mechanical modes at gigahertz frequencies with phase velocities below the Rayleigh velocity in glass, eliminating acoustic radiation losses. We propose slot waveguides on glass with telecom optical frequencies and strong radiation pressure forces resulting in Brillouin gains on the order of 500 and 50 000 W-1m-1 for backward and forward Brillouin scattering, respectively.

  16. Stimulated brillouin scattering of electromagnetic waves in a dusty plasma

    International Nuclear Information System (INIS)

    Salimullah, M.; Sen, A.

    1991-08-01

    The stimulated Brilluoin scattering of electromagnetic waves in a homogeneous, unmagnetized and collisionless dusty plasma has been investigated theoretically. The Vlasov equation has been solved perturbatively to find the nonlinear response of the plasma particles. The presence of the dust particles introduces a background inhomogeneous electric field which significantly influences the dispersive properties of the plasma. At the ion acoustic branch we find the usual scattering slightly modified by the charged dust grains. However, at the frequency lower than the ion acoustic branch we find a new mode of the plasma arising from the oscillations of the ions in the static structure of the dust distribution. This low frequency branch causes enhanced stimulated Brillouin scattering of electromagnetic waves in a dusty plasma. (author). 15 refs

  17. Influence of core diameter and length of polymer optical fiber on Brillouin scattering properties

    Science.gov (United States)

    Mizuno, Yosuke; Ishigure, Takaaki; Nakamura, Kentaro

    2012-02-01

    Brillouin scattering in perfluorinated graded-index polymer optical fibers (PFGI-POFs) is potentially useful in developing high-accuracy distributed temperature sensors with reduced strain sensitivity. In this study, we investigate, both experimentally and theoretically, the influence of the fiber core diameter and length on the Brillouin gain spectra (BGS) in PFGI-POFs. First, we show that smaller core diameter drastically enhances the Stokes power using PFGI-POFs with 62.5-μm and 120-μm core diameters, and discuss the Brillouin threshold power. Then, we demonstrate that the PFGI-POF length has little influence on the BGS when the length is longer than 50 m. We also predict that, at 1.55-μm wavelength, it is difficult to reduce the Brillouin threshold power of PFGI-POFs below that of long silica single-mode fibers even if their core diameter is sufficiently reduced to satisfy the single-mode condition. Finally, making use of the enhanced Stokes signal, we confirm the Brillouin linewidth narrowing effect.

  18. Spontaneous Rayleigh-Brillouin scattering spectral analysis based on Wiener filter

    Science.gov (United States)

    Shang, Jingcheng; Wu, Tao; Yang, Chuanyin; Yu, Huan; He, Xingdao

    2017-10-01

    In this paper, a spontaneous Rayleigh-Brillouin scattering spectrometer is developed to measure the gaseous spontaneous Rayleigh-Brillouin scattering (SRBS) profiles over the pressure range 1 to 6 atm for a wavelength of 532nm at the constant room temperature of 296K and 900 scattering angle. The measured Rayleigh-Brillouin scattering spectra are deconvolved using Wiener filtering to remove the effect of the Airy transmission function of the Fabry-Pérot scanning interferometer and get high resolution Rayleigh-Brillouin scattering spectra. The root-mean-square error is less than 2% and χ 2 is less than 15 over the pressure range 1 to 6 atm. The comparison between theoretical spectra (Tenti S6 model) and deconvolved Rayleigh-Brillouin scattering spectra is made. Some factors that effected the deconvolution of accuracy are analyzed and discussed.

  19. Micro-focused Brillouin light scattering study of the magnetization dynamics driven by Spin Hall effect in a transversely magnetized NiFe nanowire

    Energy Technology Data Exchange (ETDEWEB)

    Madami, M., E-mail: marco.madami@fisica.unipg.it; Carlotti, G. [Dipartimento di Fisica e Geologia, Università di Perugia, Perugia (Italy); Gubbiotti, G.; Tacchi, S. [Istituto Officina dei Materiali del CNR (CNR-IOM), Unità di Perugia, c/o Dipartimento di Fisica e Geologia, Università di Perugia, Perugia (Italy); Moriyama, T.; Tanaka, K.; Ono, T. [Institute for Chemical Research, Kyoto University, Kyoto (Japan); Siracusano, G.; Finocchio, G. [Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, Messina (Italy); Carpentieri, M. [Department of Electrical and Information Engineering, Politecnico of Bari, Bari (Italy)

    2015-05-07

    We employed micro-focused Brillouin light scattering to study the amplification of the thermal spin wave eigenmodes by means of a pure spin current, generated by the spin-Hall effect, in a transversely magnetized Pt(4 nm)/NiFe(4 nm)/SiO{sub 2}(5 nm) layered nanowire with lateral dimensions 500 × 2750 nm{sup 2}. The frequency and the cross section of both the center (fundamental) and the edge spin wave modes have been measured as a function of the intensity of the injected dc electric current. The frequency of both modes exhibits a clear redshift while their cross section is greatly enhanced on increasing the intensity of the injected dc. A threshold-like behavior is observed for a value of the injected dc of 2.8 mA. Interestingly, an additional mode, localized in the central part of the nanowire, appears at higher frequency on increasing the intensity of the injected dc above the threshold value. Micromagnetic simulations were used to quantitatively reproduce the experimental results and to investigate the complex non-linear dynamics induced by the spin-Hall effect, including the modification of the spatial profile of the spin wave modes and the appearance of the extra mode above the threshold.

  20. Brillouin light scattering from surface acoustic waves in a subwavelength-diameter optical fibre.

    Science.gov (United States)

    Beugnot, Jean-Charles; Lebrun, Sylvie; Pauliat, Gilles; Maillotte, Hervé; Laude, Vincent; Sylvestre, Thibaut

    2014-10-24

    Brillouin scattering in optical fibres is a fundamental interaction between light and sound with important implications ranging from optical sensors to slow and fast light. In usual optical fibres, light both excites and feels shear and longitudinal bulk elastic waves, giving rise to forward-guided acoustic wave Brillouin scattering and backward-stimulated Brillouin scattering. In a subwavelength-diameter optical fibre, the situation changes dramatically, as we here report with the first experimental observation of Brillouin light scattering from surface acoustic waves. These Rayleigh-type surface waves travel the wire surface at a specific velocity of 3,400 m s(-1) and backscatter the light with a Doppler shift of about 6 GHz. As these acoustic resonances are sensitive to surface defects or features, surface acoustic wave Brillouin scattering opens new opportunities for various sensing applications, but also in other domains such as microwave photonics and nonlinear plasmonics.

  1. Brillouin Scattering Spectrum Analysis Based on Auto-Regressive Spectral Estimation

    Science.gov (United States)

    Huang, Mengyun; Li, Wei; Liu, Zhangyun; Cheng, Linghao; Guan, Bai-Ou

    2018-03-01

    Auto-regressive (AR) spectral estimation technology is proposed to analyze the Brillouin scattering spectrum in Brillouin optical time-domain refelectometry. It shows that AR based method can reliably estimate the Brillouin frequency shift with an accuracy much better than fast Fourier transform (FFT) based methods provided the data length is not too short. It enables about 3 times improvement over FFT at a moderate spatial resolution.

  2. Brillouin light scattering spectroscopy for tissue engineering application

    Science.gov (United States)

    Akilbekova, Dana; Yakupov, Talgat; Ogay, Vyacheslav; Umbayev, Bauyrzhan; Yakovlev, Vladislav V.; Utegulov, Zhandos N.

    2018-02-01

    Biomechanical properties of mammalian bones, such as strength, toughness and plasticity, are essential for understanding how microscopic scale mechanical features can link to macroscale bones' strength and fracture resistance. We employ Brillouin light scattering (BLS) micro-spectroscopy for local assessment of elastic properties of bones under compression and the efficacy of the tissue engineering approach based on heparin-conjugated fibrin (HCF) hydrogels, bone morphogenic proteins (BMPs) and osteogenic stem cells in the regeneration of the bone tissues. BLS is noninvasive and label-free imaging modality for probing mechanical properties of hard tissues that can give information on structure-function properties of normal and pathological tissues. Results showed that HCF gels containing combination of all factors had the best effect with complete defect regeneration at week 9 and that the bones with fully consolidated fractures have higher values of elastic moduli compared to the bones with defects.

  3. Unusual features of long-range density fluctuations in glass-forming organic liquids: A Rayleigh and Rayleigh-Brillouin light scattering study

    International Nuclear Information System (INIS)

    Patkowski, A.; Fischer, E. W.; Steffen, W.; Glaser, H.; Baumann, M.; Ruths, T.; Meier, G.

    2001-01-01

    A new feature of glass-forming liquids, i.e., long-range density fluctuations of the order of 100 nm, has been extensively characterized by means of static light scattering, photon correlation spectroscopy and Rayleigh-Brillouin spectroscopy in orthoterphenyl (OTP) and 1,1-di(4 # prime#-methoxy-5 # prime#methyl-phenyl)-cyclohexane (BMMPC). These long-range density fluctuations result in the following unusual features observed in a light scattering experiment, which are not described by the existing theories: (i) strong q-dependent isotropic excess Rayleigh intensity, (ii) additional slow component in the polarized photon correlation function, and (iii) high Landau-Placzek ratio. These unusual features are equilibrium properties of the glass-forming liquids and depend only on temperature, provided that the sample has been equilibrated long enough. The temperature-dependent equilibration times were measured for BMMPC and are about 11 orders of magnitude longer than the α process. It was found that the glass-forming liquid OTP may occur in two states: with and without long-range density fluctuations ('clusters'). We have characterized the two states by static and dynamic light scattering in the temperature range from T g to T g +200 K. The relaxation times of the α process as well as the parameters of the Brillouin line are identical in both OTP with and without clusters. The α process (density fluctuations) in OTP was characterized by measuring either the polarized (VV) or depolarized (VH) correlation function, which are practically identical and q-independent. This feature, which is commonly observed in glass-forming liquids, is not fully explained by the existing theories

  4. Rayleigh-Brillouin scattering in NH4Cl under hydrostatic pressure

    International Nuclear Information System (INIS)

    Hikita, Tomoyuki; Kitabatake, Makoto; Ikeda, Takuro

    1981-01-01

    Rayleigh-Brillouin scattering in NH 4 Cl has been studied under hydrostatic pressure. Brillouin shifts of the longitudinal phonons propagating along the and directions and of the transverse phonons propagating along the direction are measured as a function of temperature at four fixed pressures up to 2.3 kbar. All components increase almost linearly with decreasing temperature in the disordered phase and show incremental increases similar to the temperature dependence of the long range order parameter in the ordered phase. It was found that the longitudinal modes exhibit large despersion effect even at high pressures. On the other hand, the transverse mode appears to give no dispersion effect. The intensity of the Rayleigh component in the VV polarization condition increases as the temperature approaches the transition point, while that in the VH polarization does not show such anomalous increase. (author)

  5. Multi-wavelength Praseodymium fiber laser using stimulated Brillouin scattering

    Science.gov (United States)

    Ahmad, H.; Aidit, S. N.; Tiu, Z. C.

    2018-02-01

    A multi-wavelength Brillouin Praseodymium fiber laser (MWBPFL) operating at 1300 nm region is demonstrated based on the hybrid scheme by utilizing Brillouin gain medium and Praseodymium-doped fluoride fiber as linear gain medium. A 15 μm air gap is incorporated into the cavity to allow the switching of Brillouin frequency spacing from double to single spacing. Under the Brillouin pump of 8 dBm and the 1020 nm pump power of 567.2 mW, 36 Stokes lines with a wavelength spacing of 0.16 nm and 24 Stokes lines with a wavelength spacing of 0.08 nm are achieved. The wavelength tunability of 8 nm is realized for both MWBPFLs by shifting the Brillouin pump wavelength. The MWBPFLs exhibit an excellent stability in the number of generated Stokes and power level over one-hour period.

  6. Anti-Stokes scattering and Stokes scattering of stimulated Brillouin scattering cascade in high-intensity laser-plasma interaction

    Science.gov (United States)

    Feng, Q. S.; Liu, Z. J.; Zheng, C. Y.; Xiao, C. Z.; Wang, Q.; Zhang, H. C.; Cao, L. H.; He, X. T.

    2017-07-01

    Anti-Stokes scattering and Stokes scattering in stimulated Brillouin scattering (SBS) cascades have been researched using the Vlasov-Maxwell simulation. In high-intensity laser-plasma interactions, stimulated anti-Stokes Brillouin scattering (SABS) will occur after second stage SBS rescattering. The mechanism of SABS has been put forward to explain this phenomenon. In the early phase of SBS evolution, only first stage SBS appears and total SBS reflectivity comes from first stage SBS. However, when high-stage SBS and SABS occur, SBS reflectivity will display burst behavior and the total reflectivity comes from the SBS cascade and SABS superimposition. The SABS will compete with the SBS rescattering to determine the total SBS reflectivity. Thus, SBS rescattering including SABS is an important saturation mechanism of SBS and should be taken into account in high-intensity laser-plasma interaction.

  7. Elastic properties of boron carbide films via surface acoustic waves measured by Brillouin light scattering

    Energy Technology Data Exchange (ETDEWEB)

    Salas, E.; Jimenez-Villacorta, F.; Jimenez Rioboo, R.J.; Prieto, C. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, Cantoblanco, 28049 Madrid (Spain); Sanchez-Marcos, J. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, Cantoblanco, 28049 Madrid (Spain); Departamento de Quimica-Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Munoz-Martin, A.; Prieto, J.E.; Joco, V. [Centro de Microanalisis de Materiales, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

    2013-03-15

    Surface acoustic wave (SAW) velocity has been determined by high resolution Brillouin light scattering to study the mechano-elastic properties of boron carbide films prepared by radio frequency (RF) sputtering. The comparison of experimentally observed elastic behaviour with simulations made by considering film composition obtained from elastic recoil detection analysis-time of flight (ERDA-ToF) spectroscopy allows establishing that elastic properties are determined by that of crystalline boron carbide with a lessening of the SAW velocity values due to surface oxidation. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Wide-range temperature dependences of Brillouin scattering properties in polymer optical fiber

    Science.gov (United States)

    Minakawa, Kazunari; Hayashi, Neisei; Shinohara, Yuri; Tahara, Masaki; Hosoda, Hideki; Mizuno, Yosuke; Nakamura, Kentaro

    2014-04-01

    We investigate the temperature dependences of the Brillouin scattering properties in a perfluorinated graded-index (PFGI-) polymer optical fiber (POF) in a wide temperature range from -160 to 125 °C. The temperature dependences of the Brillouin frequency shift, linewidth, and Stokes power are almost linear at lower temperature down to -160 °C while they show nonlinear dependences at higher temperature. These behaviors appear to originate from the partial glass transition of the polymer material.

  9. Brillouin scattering, piezobirefringence, and dispersion of photoelastic coefficients of CdS and ZnO

    DEFF Research Database (Denmark)

    Berkowicz, R.; Skettrup, Torben

    1975-01-01

    We have measured the dispersion of the Brillouin scattering from acoustoelectrical domains in CdS and ZnO. These spectra are compared with the birefringence spectra obtained by applying uniaxial stress. The resonant cancellation of the Brillouin scattering occurs at the spectral position of the i......We have measured the dispersion of the Brillouin scattering from acoustoelectrical domains in CdS and ZnO. These spectra are compared with the birefringence spectra obtained by applying uniaxial stress. The resonant cancellation of the Brillouin scattering occurs at the spectral position...... of the isotropic point of the stress-induced birefringence. From these spectra it is concluded that the Brillouin scattering in CdS and ZnO is determined by elasto-optic effects alone. The spectra of some of the photoelastic coefficients have been determined. A model dielectric constant is derived where both....... It is found that the exchange interaction between the excitons may change the values of the photoelastic coefficients in ZnO about 10%....

  10. Spontaneous Rayleigh-Brillouin scattering of ultraviolet light in nitrogen, dry and moist air

    NARCIS (Netherlands)

    Witschas, B.; Vieitez, M.O.; van Duijn, E.-J.; Reitebuch, O.; Van de Water, W.; Ubachs, W.M.G.

    2010-01-01

    Atmospheric lidar techniques for the measurement of wind, temperature, and optical properties of aerosols rely on the exact knowledge of the spectral line shape of the scattered laser light on molecules. We report on spontaneous Rayleigh-Brillouin scattering measurements in the ultraviolet at a

  11. Elastic constants and dimensions of imprinted polymeric nanolines determined from Brillouin light scattering

    International Nuclear Information System (INIS)

    Johnson, W L; Kim, S A; Geiss, R; Flannery, C M; Soles, C L; Wang, C; Stafford, C M; Wu, W-L; Torres, J M; Vogt, B D; Heyliger, P R

    2010-01-01

    Elastic constants and cross-sectional dimensions of imprinted nanolines of poly(methyl methacrylate) (PMMA) on silicon substrates are determined nondestructively from finite-element inversion analysis of dispersion curves of hypersonic acoustic modes of these nanolines measured with Brillouin light scattering. The results for the cross-sectional dimensions, under the simplifying assumption of vertical sides and a semicircular top, are found to be consistent with dimensions determined from critical-dimension small-angle x-ray scattering measurements. The elastic constants C 11 and C 44 are found to be, respectively, 11.6% and 3.1% lower than their corresponding values for bulk PMMA. This result is consistent with the dimensional dependence of the quasi-static Young's modulus determined from buckling measurements on PMMA films with lower molecular weights. This study provides the first evidence of size-dependent effects on hypersonic elastic properties of polymers.

  12. Observation of depolarized guided acoustic-wave Brillouin scattering in partially uncoated optical fibers

    Science.gov (United States)

    Hayashi, Neisei; Set, Sze Yun; Yamashita, Shinji

    2018-02-01

    We observed the depolarized guided acoustic-wave Brillouin scattering (GAWBS) spectrum in a highly nonlinear fiber with a partially side-stripped polymer coat. The linewidth of the GAWBS spectral line at 941 MHz was measured to be 6.4 MHz, which was 0.9 times that of a coated fiber.

  13. Effects of hydrodynamics on Stimulated Brillouin Scattering in multiple plasma interaction

    International Nuclear Information System (INIS)

    Yahia, V.; Depierreux, S.; Goyon, C.; Loisel, G.; Borisenko, N. G.; Masson-Laborde, P. E.; Orekhov, A.; Rienecker, T.; Rosmej, O.; Labaune, C.

    2013-01-01

    In this paper, an experiment carried out on LULI2000 facility is presented. It was designed to investigate how two successive plasmas interact through hydrodynamic coupling and electromagnetic radiations. Contributions of both effects have been successfully identified and the effects of hydrodynamic coupling on Stimulated Brillouin Scattering has been observed. (authors)

  14. Temperature retrieval from Rayleigh-Brillouin scattering profiles measured in air

    NARCIS (Netherlands)

    Witschas, B.; Ubachs, W.M.G.

    2014-01-01

    In order to investigate the performance of two different algorithms for retrieving temperature from Rayleigh-Brillouin (RB) line shapes, RB scattering measurements have been performed in air at a wavelength of 403 nm, for a temperature range from 257 K to 330 K, and atmospherically relevant

  15. Rayleigh-Brillouin scattering profiles of air at different temperatures and pressures

    NARCIS (Netherlands)

    Gu, Z.; Witschas, B.; van der Water, W.; Ubachs, W.M.G.

    2013-01-01

    Rayleigh-Brillouin (RB) scattering profiles for air have been recorded for the temperature range from 255 to 340 K and the pressure range from 640 to 3300 mbar, covering the conditions relevant for the Earth's atmosphere and for planned atmospheric light detection and ranging (LIDAR) missions. The

  16. Suppression of Stimulated Brillouin Scattering in Optical Fibers Using a Linearly Chirped Diode Laser

    Science.gov (United States)

    2012-07-02

    output,” Proc. SPIE 7914, 79140B, 79140B-8 (2011). 9. C. G. Carlson, R. B. Ross, J. M. Schafer, J. B. Spring, and B. G. Ward, “Full vectorial analysis...Stimulated Brillouin scattering (SBS) is a major factor limiting the output power of a fiber laser. In a lossless, passive fiber, SBS occurs when the product

  17. Anti-Stokes scattering and Stokes scattering of stimulated Brillouin scattering cascade in high-intensity laser-plasmas interaction

    Science.gov (United States)

    Feng, Qingsong; Zheng, Chunyang; Liu, Zhanjun; Xiao, Chengzhuo; Wang, Qing; Cao, Lihua; He, Xiantu

    2017-10-01

    The anti-Stokes scattering and Stokes scattering in stimulated Brillouin scattering (SBS) cascade have been researched by the Vlasov-Maxwell simulation. In the high-intensity laser-plasmas interaction, the stimulated anti-Stokes Brillouin scattering (SABS) will occur after the second stage SBS rescattering. The mechanism of SABS has been put forward to explain this phenomenon. In the early time of SBS evolution, only the first stage SBS appears, and the total SBS reflectivity comes from the first stage SBS. However, when the high-stage SBS and SABS occur, the SBS reflectivity will appear a burst behavior, and the total reflectivity comes from the SBS cascade and SABS superimposition. The SABS will compete with the SBS rescattering to determine the total SBS reflectivity. Thus, the SBS rescattering including the SABS is an important saturation mechanism of SBS, and should be taken into account in the high-intensity laser-plasmas interaction. This research was supported by the National Natural Science Foundation of China (Grant Nos. 11375032, 11575035, 11475030 and 11435011), National Basic Research Program of China (Grant No. 2013CB834101) and Science Challenge Project, No. TZ2016005.

  18. Brillouin-scattering measurements of the acoustic absorption coefficient in liquid CS2

    Science.gov (United States)

    Coakley, R. W.; Detenbeck, R. W.

    1975-01-01

    High-resolution Brillouin spectra were recorded for light scattered at small angles from liquid CS2. The use of a single-mode He-Ne laser, locked in frequency to a Fabry-Perot interferometer, permitted measurements of line widths of the order of 10 MHz for frequencies in the range 300-1000 MHz. These measurements extend previous Brillouin line-width measurements at higher frequencies into the region where relaxation effects are dominant and connect the optical measurements with lower-frequency acoustical data.

  19. Stimulated Brillouin scattering continuous wave phase conjugation in step-index fiber optics.

    Science.gov (United States)

    Massey, Steven M; Spring, Justin B; Russell, Timothy H

    2008-07-21

    Continuous wave (CW) stimulated Brillouin scattering (SBS) phase conjugation in step-index optical fibers was studied experimentally and modeled as a function of fiber length. A phase conjugate fidelity over 80% was measured from SBS in a 40 m fiber using a pinhole technique. Fidelity decreases with fiber length, and a fiber with a numerical aperture (NA) of 0.06 was found to generate good phase conjugation fidelity over longer lengths than a fiber with 0.13 NA. Modeling and experiment support previous work showing the maximum interaction length which yields a high fidelity phase conjugate beam is inversely proportional to the fiber NA(2), but find that fidelity remains high over much longer fiber lengths than previous models calculated. Conditions for SBS beam cleanup in step-index fibers are discussed.

  20. Theoretical analysis and experiment performance of slow-light based on stimulated Brillouin scattering (SBS)

    International Nuclear Information System (INIS)

    Zhou Hongyan; Zhong Kun; Zhang Ru; Lang Peilin

    2011-01-01

    Slow light technology will play a key role in future all-optical communication. The slow-light technology based on stimulated Brillouin scattering has become a research highlight because of its additional advantages, such as compatibility of the devices with existing telecommunication systems, room-temperature operation, and tunable at arbitrary wavelengths. According to the propagation of a cw pulse through a Brillouin fiber amplifier, whose frequency is near the Stokes resonance, via three-wave coupling equations, both pump depletion and fiber losses taken into consideration, the principle of how slow-light effect based on stimulated Brillouin scattering produced and the mathematical expression of time delay are strictly deduced. A delay of 8 ns is obtained when the input Stokes pulse is 200ns and the SBS (stimulated Brillouin scattering) gain G is ∼18 in our designed experiment of SBS slow-light system. Then the extent of transformation from pump waves to Stokes waves is measured using MATLAB numerical simulation according to the experiment dates, based on the relation between output pump light power and input pump light power and also the relation between output Stokes light power and input pump light power. And the relation between the input light power and propagation distance is discussed as well. Finally the relation between slow light pulse delay and SBS gain is also obtained.

  1. An ultrawide tunable range single passband microwave photonic filter based on stimulated Brillouin scattering.

    Science.gov (United States)

    Xiao, Yongchuan; Guo, Jing; Wu, Kui; Qu, Pengfei; Qi, Huajuan; Liu, Caixia; Ruan, Shengping; Chen, Weiyou; Dong, Wei

    2013-02-11

    A single passband microwave photonic filter with ultrawide tunable range based on stimulated Brillouin scattering is theoretically analyzed. Combining the gain and loss spectrums, tuning range with 44GHz is obtained without crosstalk by introducing two pumps. Adding more pumps, Tuning range multiplying with the multiplication factor equaling to the total quantity of pump can be achieved, which has potential application in microwave and millimeter wave wireless communication systems.

  2. Rayleigh-Brillouin scattering in SF6 in the kinetic regime

    NARCIS (Netherlands)

    Wang, Yuanqing; Yu, Yin; Liang, Kun; Marques, Wilson; van de Water, Willem; Ubachs, Wim

    2017-01-01

    Rayleigh-Brillouin spectral profiles are measured with a laser-based scatterometry setup for a 90° scattering angle at a high signal-to-noise ratio (r.m.s. noise below 0.15% w.r.t. peak intensity) in sulfur-hexafluoride gas for pressures in the range 0.2–5 bar and for a wavelength of λ=403.0 nm. The

  3. Brillouin Light Scattering from Magnetic Excitations in Superparamagnetic and Ferromagnetic Co-Al-O Granular Films

    Science.gov (United States)

    Yoshihara, Akira; Maeda, Toshiteru; Kawamura, Satoshi; Nakamura, Shintaro; Nojima, Tsutomu; Takeda, Yoshihiko; Ohnuma, Shigehiro

    2018-04-01

    A systematic study of Brillouin light scattering (BLS) from superparamagnetic (SPM) and ferromagnetic (FM) Co-Al-O granular films was performed under magnetic fields of up to 4.6 kOe in the standard backscattering geometry at room temperature. The SPM and FM boundary, defined as the Co composition at which the exchange field vanishes, was found to be located at xC(Co) = 59.3 ± 1.3 at. %. From FM films we observed a pair of bulk spin-wave peaks on both the positive- and negative-frequency sides and a surface localized Damon-Eshbach peak only on the positive-frequency side under the present scattering conditions. From SPM films, a pair of broader but propagative excitation peaks with asymmetric intensity were observed on both frequency sides in a spectrum. We performed a numerical analysis of the BLS spectrum by employing the theory developed by Camley and Mills (CM) while retaining dipole and exchange couplings for FM films and only dipole coupling for SPM films. The CM theory successfully reproduced the observed spectrum for both SPM and FM films. The SPM spectrum exhibits a singlet-doublet peak structure similarly to an FM SW spectrum. The SPM peak stems from the dipole-coupled larger-amplitude precession motion of the granule magnetic moment around the external-field-induced magnetization.

  4. Stimulated Brillouin scattering of an electromagnetic wave in weakly ...

    Indian Academy of Sciences (India)

    The importance of the laser–plasma interaction becomes an active field of research in the laser-fusion experiments, charged particle acceleration experiments, X-ray generation, propagation of EM waves in ionosphere etc. and the stimulated Bril- louin scattering (SBS) plays an important role in laser–plasma interaction as it.

  5. Does Brillouin light scattering probe the primary glass transition process at temperatures well above glass transition?

    Science.gov (United States)

    Voudouris, P; Gomopoulos, N; Le Grand, A; Hadjichristidis, N; Floudas, G; Ediger, M D; Fytas, G

    2010-02-21

    The primary alpha-relaxation time (tau(alpha)) for molecular and polymeric glass formers probed by dielectric spectroscopy and two light scattering techniques (depolarized light scattering and photon correlation spectroscopy) relates to the decay of the torsional autocorrelation function computed by molecular dynamics simulation. It is well known that Brillouin light scattering spectroscopy (BLS) operating in gigahertz frequencies probes a fast (10-100 ps) relaxation of the longitudinal modulus M*. The characteristic relaxation time, irrespective of the fitting procedure, is faster than the alpha-relaxation which obeys the non-Arrhenius Vogel-Fulcher-Tammann equation. Albeit, this has been noticed, it remains a puzzling finding in glass forming systems. The available knowledge is based only on temperature dependent BLS experiments performed, however, at a single wave vector (frequency). Using a new BLS spectrometer, we studied the phonon dispersion at gigahertz frequencies in molecular [o-terphenyl (OTP)] and polymeric [polyisoprene (PI) and polypropylene (PP)] glass formers. We found that the hypersonic dispersion does relate to the glass transition dynamics but the disparity between the BLS-relaxation times and tau(alpha) is system dependent. In PI and PP, the former is more than one order of magnitude faster than tau(alpha), whereas the two relaxation times become comparable in the case of OTP. The difference between the two relaxation times appears to relate to the "breadth" of the relaxation time distribution function. In OTP the alpha-relaxation process assumes a virtually single exponential decay at high temperatures well above the glass transition temperature, in clear contrast with the case of the amorphous bulk polymers.

  6. A fully computerized multi-pass Fabry-Perot interferometer for Rayleigh-Brillouin scattering experiments

    International Nuclear Information System (INIS)

    Bohidar, H.; Berland, T.; Boger, F.; Joessang, T.; Feder, J.

    1987-01-01

    The development of a Multipass Fabry-Perot interforometer assembly for use in Rayleigh-Brillouin scattering experiments is reported. The optical alignment and the scattered signal data acquisition have been completely computerized. Digital scanning and alignment strategies of the Fabry-Perot resonator have been incorporated, which makes this instrument quite unique in this respect. The high contrast (∼10 10 ) and finesse (∼50) offered by this instrument makes it possible to detect Brillouin peaks from samples that have a small Brillouin scattering cross-section. As part of this system a compatible and precision sample chamber has been constructed, which has been designed to operate in the pressure and temperature ranges of 1-1000B and 20-150 o C, respectively. The cell has been constructed to be small and compact, but it still has a large heat capacity (∼250J/K) which ensures easy and stable temperature control of the liquid sample volume which has a size of 40 mm 3 . The achievable temperature stability is +-1mK and +-2mK for operating temperatures below and above 100 o C, respectively. The pressure stability is in the range of +-0.05B of the set pressure for pressures below 100B and it is +-0.05% for higher pressures up to 1000B. Both pressure and temperature are remotely monitored and controlled by a ND/100 computer. Special care has been taken in designing the optics of the pressure cell to ensure that both the primary and secondary reflections from the entrance window, as well as the main beam, go out of the scattering region in order to achieve higher signal-to-noise ratio in actual experiments

  7. Rayleigh-Brillouin scattering to determine one-dimensional temperature and number density profiles of a gas flow field

    Science.gov (United States)

    Lock, James A.; Seasholtz, Richard G.; John, W. T.

    1992-01-01

    Rayleigh-Brillouin spectra for heated nitrogen gas were measured by imaging the output of a Fabry-Perot interferometer onto a CCD array. The spectra were compared with the theoretical 6-moment model of Rayleigh-Brillouin scattering convolved with the Fabry-Perot instrument function. Estimates of the temperature and a dimensionless parameter proportional to the number density of the gas as functions of position in the laser beam were calculated by least-squares deviation fits between theory and experiment.

  8. Stimulated Brillouin scattering in dispersion-decreasing fiber with ultrahigh-speed femtosecond soliton pulse compression.

    Science.gov (United States)

    Hirooka, Toshihiko; Ono, Shinpei; Hagiuda, Ken-ichi; Nakazawa, Masataka

    2005-02-15

    We report that stimulated Brillouin scattering (SBS) in a dispersion-decreasing fiber (DDF) is particularly disadvantageous with ultrahigh-speed femtosecond soliton compression that exceeds 40 GHz. It is important to note that the increase in the longitudinal mode power of a soliton is proportional to the square of the repetition rate. The SBS threshold is determined by the dispersion-decreasing rate of the DDF, rather than its fiber loss. We suppressed the SBS by applying 30-MHz frequency modulation to a mode-locked fiber laser and successfully obtained a stable 40-GHz, 100-fs pulse train.

  9. Observation of spin-wave dispersion in Nd-Fe-B magnets using neutron Brillouin scattering

    International Nuclear Information System (INIS)

    Ono, K.; Inami, N.; Saito, K.; Takeichi, Y.; Kawana, D.; Yokoo, T.; Itoh, S.; Yano, M.; Shoji, T.; Manabe, A.; Kato, A.; Kaneko, Y.

    2014-01-01

    The low-energy spin-wave dispersion in polycrystalline Nd-Fe-B magnets was observed using neutron Brillouin scattering (NBS). Low-energy spin-wave excitations for the lowest acoustic spin-wave mode were clearly observed. From the spin-wave dispersion, we were able to determine the spin-wave stiffness constant D sw (100.0 ± 4.9 meV.Å 2 ) and the exchange stiffness constant A (6.6 ± 0.3 pJ/m)

  10. Distributed Strain Measurement along a Concrete Beam via Stimulated Brillouin Scattering in Optical Fibers

    Directory of Open Access Journals (Sweden)

    Romeo Bernini

    2011-01-01

    Full Text Available The structural strain measurement of tension and compression in a 4 m long concrete beam was demonstrated with a distributed fiber-optic sensor portable system based on Brillouin scattering. Strain measurements provided by the fiber-optic sensor permitted to detect the formation of a crack in the beam resulting from the external applied load. The sensor system is valuable for structural monitoring applications, enabling the long-term performance and health of structures to be efficiently monitored.

  11. Angular characteristics of the stimulated-Brillouin-scattering spectrum from a laser plasma with strong acoustic-wave damping

    International Nuclear Information System (INIS)

    Saikia, P.

    1981-01-01

    The spectrum of stimulated Brillouin scattering from an inhomogeneous moving laser plasma is analyzed. The damping of acoustic waves and scattered electromagnetic waves is taken into account. Spectra are derived for various scattering angles and for various radii of the laser beam. For all observation angles the center of the spectral line is at an unshifted frequency. As the observation angle increases, the width of the red wing in the spectrum increases. The intensity of the scattered light is very anisotropic

  12. Brillouin Spectroscopy Data Base for Biological Threats

    National Research Council Canada - National Science Library

    Rubel, Glenn

    2003-01-01

    .... Brillouin scattering from DNA, ovalbumen, the Bacillus spores globigii and thuringiensis were measured to determine the feasibility of biological material discrimination using Brillouin scattering...

  13. Transition from hydrodynamic to fast sound in a He-Ne mixture a neutron Brillouin scattering experiment

    CERN Document Server

    Bafile, U; Barocchi, F; Sampoli, M

    2002-01-01

    The presence of a fast-sound mode in the microscopic dynamics of the rare-gas mixture He-Ne, predicted by theoretical studies and molecular-dynamics simulations, was demonstrated by an inelastic neutron scattering experiment. In order to study the transition between the fast and the normal acoustic modes in the hydrodynamic regime, k values lower by about one order of magnitude than in the usual experiments have to be probed. We describe here the results of the first neutron Brillouin scattering experiment performed with this purpose on the same system already investigated at larger k. The results of both experiments, together with those of a new molecular-dynamics simulation, provide a complete and consistent description, still missing so far, of the onset of fast-sound propagation in a binary mixture. (orig.)

  14. Water dynamics in a lithium chloride aqueous solution probed by Brillouin neutron and x-ray scattering.

    Science.gov (United States)

    Mamontov, E; De Francesco, A; Formisano, F; Laloni, A; Sani, L; Leu, B M; Said, A H; Kolesnikov, A I

    2012-02-15

    We studied the collective excitations in an aqueous solution of lithium chloride over the temperature range of 270-205 K using neutron and x-ray Brillouin scattering. Both neutron and x-ray experiments revealed the presence of low- and high-frequency excitations, similar to the low- and high-frequency excitations in pure water. These two excitations were detectable through the entire temperature range of the experiment, at all probed values of the scattering momentum transfer (0.2 Å(-1) temperature range was investigated using elastic intensity neutron and x-ray scans. Clear evidence of the crossover in the dynamics of the water molecules in the solution was observed in the single-particle relaxational dynamics on the µeV (nanosecond) time scale, but not in the collective dynamics on the meV (picosecond) time scale.

  15. Neutron Brillouin scattering experiments with pulsed neutrons on high resolution chopper spectrometer HRC

    International Nuclear Information System (INIS)

    Itoh, S; Yokoo, T; Endoh, Y; Kawana, D; Kaneko, Y; Tokura, Y; Fujita, M; Yoshida, K; Saito, K; Inami, N; Takeichi, Y; Ono, K

    2014-01-01

    We improved the High Resolution Chopper Spectrometer (HRC), which is installed at MLF in J-PARC, in order to perform neutron Brillouin scattering (NBS) experiments, and successfully demonstrated a feasibility of this method. Gapless spin-wave excitations were observed in La 0.8 Sr 0.2 MnO 3 , which were in good agreement with previous results using single crystals, on the other hand, a large energy gap in the ferromagnetic spin waves was found in SrRuO 3 . Spin-wave peaks in a permanent magnet Nd 2 Fe 14 B were on the dispersion curve determined previously using a single crystal. Excitations, so-called fast sound, in liquid D 2 O were in a good agreement with previous inelastic neutron scattering experiments and the dispersion curve were extended to the lower Q region.

  16. Dimensionality reduction and dynamical filtering: Stimulated Brillouin scattering in optical fibers.

    Science.gov (United States)

    Setra, Rafael G; Arroyo-Almanza, Diana A; Ni, Zetian; Murphy, Thomas E; Roy, Rajarshi

    2015-08-01

    Stimulated Brillouin scattering (SBS) is a noise-driven nonlinear interaction between acoustical and optical waves. In optical fibers, SBS can be observed at relatively low optical powers and can severely limit signal transmission. Although SBS is initiated by high dimensional noise, it also exhibits many of the hallmarks of a complex nonlinear dynamical system. We report here a comprehensive experimental and numerical study of the fluctuations in the reflected Stokes wave produced by SBS in optical fibers. Using time series analysis, we demonstrate a reduction of dimensionality and dynamical filtering of the Stokes wave. We begin with a careful comparison of the measured average transmitted and reflected intensities from below the SBS threshold to saturation of the transmitted power. Initially the power spectra and correlation functions of the time series of the reflected wave fluctuations at the SBS threshold and above are measured and simulated. Much greater dynamical insight is provided when we study the scaling behavior of the intensity fluctuations using Hurst exponents and detrended fluctuation analysis for time scales extending over six orders of magnitude. At the highest input powers, we notice the emergence of three distinct dynamical scaling regimes: persistent, Brownian, and antipersistent. Next, we explore the Hilbert phase fluctuations of the intensity time series and amplitude-phase coupling. Finally, time-delay embedding techniques reveal a gradual reduction in dimensionality of the spatiotemporal dynamics as the laser input is increased toward saturation of the transmitted power. Through all of these techniques, we find a transition from noisier to smoother dynamics with increasing input power. We find excellent agreement between our experimental measurements and simulations.

  17. Dimensionality reduction and dynamical filtering: Stimulated Brillouin scattering in optical fibers

    Science.gov (United States)

    Setra, Rafael G.; Arroyo-Almanza, Diana A.; Ni, Zetian; Murphy, Thomas E.; Roy, Rajarshi

    2015-08-01

    Stimulated Brillouin scattering (SBS) is a noise-driven nonlinear interaction between acoustical and optical waves. In optical fibers, SBS can be observed at relatively low optical powers and can severely limit signal transmission. Although SBS is initiated by high dimensional noise, it also exhibits many of the hallmarks of a complex nonlinear dynamical system. We report here a comprehensive experimental and numerical study of the fluctuations in the reflected Stokes wave produced by SBS in optical fibers. Using time series analysis, we demonstrate a reduction of dimensionality and dynamical filtering of the Stokes wave. We begin with a careful comparison of the measured average transmitted and reflected intensities from below the SBS threshold to saturation of the transmitted power. Initially the power spectra and correlation functions of the time series of the reflected wave fluctuations at the SBS threshold and above are measured and simulated. Much greater dynamical insight is provided when we study the scaling behavior of the intensity fluctuations using Hurst exponents and detrended fluctuation analysis for time scales extending over six orders of magnitude. At the highest input powers, we notice the emergence of three distinct dynamical scaling regimes: persistent, Brownian, and antipersistent. Next, we explore the Hilbert phase fluctuations of the intensity time series and amplitude-phase coupling. Finally, time-delay embedding techniques reveal a gradual reduction in dimensionality of the spatiotemporal dynamics as the laser input is increased toward saturation of the transmitted power. Through all of these techniques, we find a transition from noisier to smoother dynamics with increasing input power. We find excellent agreement between our experimental measurements and simulations.

  18. Rayleigh-Brillouin light scattering spectroscopy of nitrous oxide (N2O)

    Science.gov (United States)

    Wang, Y.; Liang, K.; van de Water, W.; Marques, W.; Ubachs, W.

    2018-02-01

    High signal-to-noise and high-resolution light scattering spectra are measured for nitrous oxide (N2O) gas at an incident wavelength of 403.00 nm, at 90° scattering, at room temperature and at gas pressures in the range 0.5 - 4 bar. The resulting Rayleigh-Brillouin light scattering spectra are compared to a number of models describing in an approximate manner the collisional dynamics and energy transfer in this gaseous medium of this polyatomic molecular species. The Tenti-S6 model, based on macroscopic gas transport coefficients, reproduces the scattering profiles in the entire pressure range at less than 2% deviation at a similar level as does the alternative kinetic Grad's 6-moment model, which is based on the internal collisional relaxation as a decisive parameter. A hydrodynamic model fails to reproduce experimental spectra for the low pressures of 0.5-1 bar, but yields very good agreement ( viscosity of ηb ∼(6 ± 2) ×10-5 Pa · s. A 'rough-sphere' model, previously shown to be effective to describe light scattering in SF6 gas, is not found to be suitable, likely in view of the non-sphericity and asymmetry of the N-N-O structured linear polyatomic molecule.

  19. Bandwidth-tunable narrowband rectangular optical filter based on stimulated Brillouin scattering in optical fiber.

    Science.gov (United States)

    Wei, Wei; Yi, Lilin; Jaouën, Yves; Hu, Weisheng

    2014-09-22

    We propose a rectangular optical filter based on stimulated Brillouin scattering (SBS) in optical fiber with bandwidth tuning from 50 MHz to 4 GHz at less than 15-MHz resolution. The rectangular shape of the filter is precisely achieved utilizing digital feedback control of the comb-like pump spectral lines. The passband ripple is suppressed to ~1 dB by mitigating the nonlinearity influences of the comb-like pump lines generated in electrical and optical components and fibers. Moreover a fiber with a single Brillouin peak is employed to further reduce the in-band ripple and the out-of-band SBS gain at the same time. Finally, we analyze the noise performance of the filter at different bandwidth cases and demonstrate the system performance of the proposed filter with 2.1-GHz bandwidth and 19-dB gain by amplifying a 2-GHz orthogonal frequency-division-multiplexing (OFDM) signal with quadrature-phase-shift-keying (QPSK) and 16-quadrature-amplitude-modulation (16-QAM) on each subscriber.

  20. Acoustic Anomalies and Fast Relaxation Dynamics of Amorphous Progesterone as Revealed by Brillouin Light Scattering

    Directory of Open Access Journals (Sweden)

    Tae Hyun Kim

    2017-12-01

    Full Text Available The amorphous state of pharmaceuticals has attracted much attention due to its high bioavailability and other advantages. The stability of the amorphous state in relation with the local molecular mobility is important from both fundamental and practical points of view. The acoustic properties of amorphous progesterone, one of the representative steroid hormones, were investigated by using a Brillouin inelastic light scattering technique. The Brillouin spectrum of the longitudinal acoustic mode exhibited distinct changes at the glass transition and the cold-crystallization temperatures. The acoustic dispersions of the longitudinal sound velocity and the acoustic absorption coefficient were attributed to the fast and possibly the secondary relaxation processes in the glassy and supercooled liquid states, while the structural relaxation process was considered as the dominant origin for the significant acoustic damping observed even in the liquid phase. The persisting acoustic dispersion in the liquid state was attributed to the single-molecule nature of the progesterone which does not exhibit hydrogen bonds in the condensed states.

  1. Suppression of Brillouin scattering in fibre-optical parametric amplifier by applying temperature control and phase modulation

    DEFF Research Database (Denmark)

    Lorenzen, Michael Rodas; Noordegraaf, Danny; Nielsen, Carsten Vandel

    2009-01-01

    An increased gain in a fibre-optical parametric amplifier through suppression of stimulated Brillouin scattering is demonstrated by applying a temperature distribution along the fibre for a fixed phase modulation of the pump. The temperature distribution slightly impacts the gain spectrum....

  2. Temperature dependence of Brillouin light scattering spectra of acoustic phonons in silicon

    International Nuclear Information System (INIS)

    Olsson, Kevin S.; Klimovich, Nikita; An, Kyongmo; Sullivan, Sean; Weathers, Annie; Shi, Li; Li, Xiaoqin

    2015-01-01

    Electrons, optical phonons, and acoustic phonons are often driven out of local equilibrium in electronic devices or during laser-material interaction processes. The need for a better understanding of such non-equilibrium transport processes has motivated the development of Raman spectroscopy as a local temperature sensor of optical phonons and intermediate frequency acoustic phonons, whereas Brillouin light scattering (BLS) has recently been explored as a temperature sensor of low-frequency acoustic phonons. Here, we report the measured BLS spectra of silicon at different temperatures. The origins of the observed temperature dependence of the BLS peak position, linewidth, and intensity are examined in order to evaluate their potential use as temperature sensors for acoustic phonons

  3. The broad Brillouin doublet and CP of KTaO3, second sound vs. Two-phonon difference scattering

    International Nuclear Information System (INIS)

    Farhi, E.; Tagantsev, A.K.; Hehlen, B.; Courtens, E.; Boatner, L.A.

    1999-01-01

    Complete text of publication follows. Low-T Brillouin spectra of the incipient ferroelectric KTaO 3 exhibit a broad central peak (CP) (1), and some additional broad Brillouin doublet (BD) (2), that can both relate to phonon-density fluctuations (3). Starting from extensive new high resolution neutron scattering measurements in pure crystals, low lying phonon sheets were modelled in the central part of Brillouin zone. Such a parameterisation was then used in order to analyse those up-mentioned unusual features in teens of two-phonon mechanisms (4). Numerical evaluations show that transverse acoustic (TA) phonons whose normal damping is faster than the BD frequency (Γ DB > ω DB ) may produce hydrodynamic second sound (propagation of heat). Moreover, two-phonon difference scattering from low damping thermal TA phonons ((Γ DB DB ) can contribute to the spectra with either a sharp or a broader BD, depending on the phonon group velocity and phonon-sheet anisotropy. The position of the doublet is consistent with both mechanisms, but comparing the computed anisotropies with experimental Brillouin and neutron scattering data, one favours the second process. (author)

  4. Geophysical Remote Sensing Using the HF Pumped Stimulated Brillouin Scatter (SBS) Emission Lines Produced by HAARP

    Science.gov (United States)

    Bernhardt, P. A.; Selcher, C. A.

    2009-12-01

    An ordinary or extraordinary mode electromagnetic wave can decay into a low frequency electrostatic wave and a scattered electromagnetic wave by a process called stimulated Brillouin scatter (SBS). The low frequency wave can be either an ion acoustic wave (IA) or an electrostatic ion cyclotron (EIC) wave. The first detection ion acoustic waves by this process during ionospheric modification with high power radio waves was reported by Norin et al. (2009) using the HAARP transmitter in Alaska. The first detection of the electrostatic ion cyclotron waves is reported here using HAARP during the March 2009 campaign. Subsequent experiments have provided additional verification of the SBS process and quantitative interpretation of the scattered wave frequency offsets to yield measurements of the electron temperatures in the heated ionosphere by Bernhardt et al. (2009). Using the SBS technique to generate ion acoustic waves, electron temperatures between 3000 and 4000 K were measured over the HAARP facility. The matching conditions for decay of the high frequency pump wave show that in addition to the production of an ion-acoustic wave, an electrostatic ion cyclotron wave can produced by the generalized SBS processes only if the pump waves makes a large angle with the magnetic field. When the EIC mode is produced, it is seen as a narrow of stimulated electromagnetic emissions at the ion cyclotron frequency. Occasionally, multiple lines are seen and analyzed to yield the relative abundance of oxygen, and molecular ions in the lower ionosphere. This ion mass spectrometer interpretation of the SBS data is new to the field of ionosphere remote sensing. In addition, based on the matching condition theory, the first profiles of the scattered wave amplitude are produced using the stimulated Brillouin scatter (SBS) matching conditions. These profiles are consistent with maximum ionospheric interactions at the upper-hybrid resonance height and at a region just below the plasma

  5. Stimulated Brillouin scattering during electron gyro-harmonic heating at EISCAT

    Directory of Open Access Journals (Sweden)

    H. Y. Fu

    2015-08-01

    Full Text Available Observations of secondary radiation, stimulated electromagnetic emission (SEE, produced during ionospheric modification experiments using ground-based, high-power, high-frequency (HF radio waves are considered. The High Frequency Active Auroral Research Program (HAARP facility is capable of generating narrowband SEE in the form of stimulated Brillouin scatter (SBS and stimulated ion Bernstein scatter (SIBS in the SEE spectrum. Such narrowband SEE spectral lines have not been reported using the European Incoherent Scatter (EISCAT heater facility before. This work reports the first EISCAT results of narrowband SEE spectra and compares them to SEE previously observed at HAARP during electron gyro-harmonic heating. An analysis of experimental SEE data shows observations of emission lines within 100 Hz of the pump frequency, interpreted as SBS, during the 2012 July EISCAT campaign. Experimental results indicate that SBS strengthens as the pump frequency approaches the third electron gyro-harmonic. Also, for different heater antenna beam angles, the CUTLASS radar backscatter induced by HF radio pumping is suppressed near electron gyro-harmonics, whereas electron temperature enhancement weakens as measured by EISCAT/UHF radar. The main features of these new narrowband EISCAT observations are generally consistent with previous SBS measurements at HAARP.

  6. Sound velocities and hypersonic dampings of Pb[(Mg1/3Nb2/3)0.45Ti0.55]O3 single crystals studied by Brillouin light scattering.

    Science.gov (United States)

    Ko, Jae-Hyeon; Kim, Tae Hyun; Kojima, Seiji; Bokov, Alexei A; Ye, Zuo-Guang

    2010-12-08

    A Brillouin spectroscopic investigation was carried out on PMN-55%PT single crystals, which are known to have no chemically ordered regions and undergo a well-defined structural phase transition at T(C) ∼ 521 K. The longitudinal and transverse sound velocities probed on a right-angle scattering geometry exhibited a remarkable softening and increasing hypersonic damping on approaching T(C) from T(B) ∼ 610 K that was characterized by the deviation of the dielectric permittivity from the high-temperature Curie-Weiss behavior. The acoustic anomalies of the longitudinal acoustic mode at the backward scattering were more substantial than those observed at the right-angle scattering, which could be understood in the framework of normal acoustic dispersion considering the difference in the acoustic frequency. The softening of the transverse sound velocity was more significant than that of the longitudinal one upon cooling toward T(C), suggesting that this acoustic anomaly may be related to the local rhombohedral transformation, occurring in polar nano-regions (PNRs). The observed acoustic behaviors combined with the central peak dynamics clearly indicated the existence of dynamic polar nano-regions in PMN-55%PT where there are no chemically ordered regions, and seem to suggest that the order parameter fluctuations due to two kinds of coupling contribute to the acoustic anomalies in the temperature range of T(C) ∼ T(B): electrostrictive coupling between the acoustic waves and the dynamic PNRs, and linear coupling between the acoustic waves and the precursor polar clusters, i.e., the ordering unit responsible for the order-disorder-type slowing down behavior probed by the central peak.

  7. Viscoelasticity of amyloid plaques in transgenic mouse brain studied by Brillouin microspectroscopy and correlative Raman analysis

    Directory of Open Access Journals (Sweden)

    Sara Mattana

    2017-11-01

    Full Text Available Amyloidopathy is one of the most prominent hallmarks of Alzheimer’s disease (AD, the leading cause of dementia worldwide, and is characterized by the accumulation of amyloid plaques in the brain parenchyma. The plaques consist of abnormal deposits mainly composed of an aggregation-prone protein fragment, β-amyloid 1-40/1-42, into the extracellular matrix. Brillouin microspectroscopy is an all-optical contactless technique that is based on the interaction between visible light and longitudinal acoustic waves or phonons, giving access to the viscoelasticity of a sample on a subcellular scale. Here, we describe the first application of micromechanical mapping based on Brillouin scattering spectroscopy to probe the stiffness of individual amyloid plaques in the hippocampal part of the brain of a β-amyloid overexpressing transgenic mouse. Correlative analysis based on Brillouin and Raman microspectroscopy showed that amyloid plaques have a complex structure with a rigid core of β-pleated sheet conformation (β-amyloid protein surrounded by a softer ring-shaped region richer in lipids and other protein conformations. These preliminary results give a new insight into the plaque biophysics and biomechanics, and a valuable contrast mechanism for the study and diagnosis of amyloidopathy.

  8. Viscoelasticity of amyloid plaques in transgenic mouse brain studied by Brillouin microspectroscopy and correlative Raman analysis

    Science.gov (United States)

    Mattana, Sara; Caponi, Silvia; Tamagnini, Francesco; Fioretto, Daniele; Palombo, Francesca

    2017-01-01

    Amyloidopathy is one of the most prominent hallmarks of Alzheimer’s disease (AD), the leading cause of dementia worldwide, and is characterized by the accumulation of amyloid plaques in the brain parenchyma. The plaques consist of abnormal deposits mainly composed of an aggregation-prone protein fragment, β-amyloid 1-40/1-42, into the extracellular matrix. Brillouin microspectroscopy is an all-optical contactless technique that is based on the interaction between visible light and longitudinal acoustic waves or phonons, giving access to the viscoelasticity of a sample on a subcellular scale. Here, we describe the first application of micromechanical mapping based on Brillouin scattering spectroscopy to probe the stiffness of individual amyloid plaques in the hippocampal part of the brain of a β-amyloid overexpressing transgenic mouse. Correlative analysis based on Brillouin and Raman microspectroscopy showed that amyloid plaques have a complex structure with a rigid core of β-pleated sheet conformation (β-amyloid) protein surrounded by a softer ring-shaped region richer in lipids and other protein conformations. These preliminary results give a new insight into the plaque biophysics and biomechanics, and a valuable contrast mechanism for the study and diagnosis of amyloidopathy. PMID:29151920

  9. Stimulated Brillouin scattering of the beat wave of two lasers in a plasma

    International Nuclear Information System (INIS)

    Panwar, Anuraj; Sharma, A. K.

    2009-01-01

    Stimulated Brillouin scattering of two collinear lasers in a plasma is investigated. Lasers exert a longitudinal ponderomotive force on electrons, imparting them oscillatory axial velocity at the beat frequency. This velocity acts as a driver for parametric excitation of an ion acoustic wave (ω,k-vector) and a noncollinear sideband electromagnetic wave (ω ' ,k-vector ' ). The driver velocity v-vector 0- couples to the sideband wave to exert a ponderomotive force at (ω,k-vector) on the electrons, driving the ion acoustic wave. The density perturbation of ion acoustic wave beats with v-vector 0- to produce a nonlinear current at (ω ' ,k-vector ' ), driving the sideband. In the case of finite spot size Gaussian laser beams, the beat wave has a Gaussian profile and excites an ion acoustic wave (ω,k-vector) and a backscattered TM mode (ω ' ,k-vector z ' ). The growth rate scales as the product of amplitudes of the lasers and maximizes at optimum values of scattering angles. The parametric instability of difference frequency driver is stronger than the sum frequency driver.

  10. Rayleigh-Brillouin scattering in SF6 in the kinetic regime

    Science.gov (United States)

    Wang, Yuanqing; Yu, Yin; Liang, Kun; Marques, Wilson; van de Water, Willem; Ubachs, Wim

    2017-02-01

    Rayleigh-Brillouin spectral profiles are measured with a laser-based scatterometry setup for a 90° scattering angle at a high signal-to-noise ratio (r.m.s. noise below 0.15% w.r.t. peak intensity) in sulfur-hexafluoride gas for pressures in the range 0.2-5 bar and for a wavelength of λ = 403.0 nm. The high quality data are compared to a number of light scattering models in order to address the effects of rotational and vibrational relaxation. While the vibrational relaxation rate is so slow that vibration degrees of freedom remain frozen, rotations relax on time scales comparable to those of the density fluctuations. Therefore, the heat capacity, the thermal conductivity and the bulk viscosity are all frequency-dependent transport coefficients. This is relevant for the Tenti model that depends on the values chosen for these transport coefficients. This is not the case for the other two models considered: a kinetic model based on rough-sphere interactions, and a model based on fluctuating hydrodynamics. The deviations with the experiment are similar between the three different models, except for the hydrodynamic model at pressures p≲ 2bar . As all models are in line with the ideal gas law, we hypothesize the presence of real gas effects in the measured spectra.

  11. Large On-Chip Amplification in Silicon via Forward Stimulated Brillouin Scattering.

    Energy Technology Data Exchange (ETDEWEB)

    Kittlaus, Eric [Yale Univ., New Haven, CT (United States); Shin, Heedeuk [Yale Univ., New Haven, CT (United States); Rakich, Peter [Yale Univ., New Haven, CT (United States)

    2015-10-15

    Strong Brillouin coupling has only recently been realized in silicon using a new class of op- tomechanical waveguides that yield both optical and phononic con nement. Despite these major advances, appreciable Brillouin ampli cation has yet to be observed in silicon. Using new membrane- suspended silicon waveguide we report large Brillouin ampli cation for the rst time, reaching levels greater than 5 dB for modest pump powers, and demonstrate a record low (5 mW) threshold for net ampli cation. This work represents a crucial advance necessary to realize high-performance Brillouin lasers and ampli ers in silicon.

  12. Brillouin Instability in Fiber Lasers Doped By Power | Bouras ...

    African Journals Online (AJOL)

    The effect of Brillouin back scattering is theoretically analysed by two-coupled modes laser model. We consider the Fabry-Perot fiber laser cavity. The rich and complex dynamic behaviours are observed. In particular the quasi periodic dynamic is identified and studied. Keywords: Stimulated Brillouin Scattering; high power ...

  13. Temperature and molecular-weight dependences of acoustic behaviors of polystyrene studied using Brillouin spectroscopy

    Science.gov (United States)

    Oh, Soo Han; Lee, Byoung Wan; Ko, Jae-Hyeon; Lee, Hyeonju; Park, Jaehoon; Ko, Young Ho; Kim, Kwang Joo

    2017-04-01

    The acoustic properties of three polystyrene polymers with different molecular weights were investigated as a function of temperature by using Brillouin light scattering. The longitudinal sound velocity showed a change in the slope, which depended on the molecular weight, at the glass transition temperature. The absorption coefficient exhibited a maximum above the glass transition temperature, and the maximum temperature became higher as the molecular weight was increased. Comparison with previous acoustic studies on polystyrene indicate that a substantial frequency dispersion caused by strong coupling between the longitudinal acoustic waves and the segmental motions exists in the high-temperature range.

  14. Single-crystal elasticity of diaspore, AlOOH, to 12 GPa by Brillouin scattering

    Science.gov (United States)

    Jiang, Fuming; Majzlan, Juraj; Speziale, Sergio; He, Duanwei; Duffy, Thomas S.

    2008-11-01

    The high-pressure elasticity of diaspore (AlOOH) has been determined by Brillouin spectroscopy to 12 GPa in diamond anvil cells. Experiments were carried out using a 16:3:1 methanol-ethanol-water mixture as pressure medium, and ruby as pressure standard. Acoustic velocities were measured in three roughly orthogonal planes at ambient and eight elevated pressures. The nine individual elastic stiffness constants of the orthorhombic crystal were obtained by fitting the velocity data to Christoffel's equation. Aggregate elastic moduli and pressure derivatives were calculated from the Cijs by fits to Eulerian finite strain equations, yielding: K=152(1) GPa, G0 = 117.2(5) GPa, (/∂P)T=3.7(1),   (=1.5(1) for the Voigt-Reuss-Hill average. All individual Cijs increase with pressure but C23 and C55 exhibit anomalously low pressure derivatives. From calculated linear compressibilities, the a-axis is the most compressible. The b-axis becomes the least compressible axis at high pressures. Over the examined pressure range, the azimuthal P-wave anisotropy decreased from 22% to 16%, while the azimuthal S-wave anisotropy increased from 15% to 21%. Both volume and axial compression curves calculated using our Brillouin results are in good agreement with the results from static compression studies. High-pressure sound velocities in diaspore exceed those of other hydrous minerals as well as many anhydrous phases relevant to Earth's upper mantle.

  15. Micro-focused Brillouin light scattering: imaging spin waves at the nanoscale

    Directory of Open Access Journals (Sweden)

    Thomas eSebastian

    2015-06-01

    Full Text Available Spin waves constitute an important part of research in the field of magnetization dynamics. Spin waves are the elementary excitations of the spin system in a magnetically ordered material state and magnons are their quasi particles. In the following article, we will discuss the optical method of Brillouin light scattering (BLS spectroscopy which is a now a well established tool for the characterization of spin waves. BLS is the inelastic scattering of light from spin waves and confers several benefits: the ability to map the spin wave intensity distribution with spatial resolution and high sensitivity as well as the potential to simultaneously measure the frequency and the wave vector and, therefore, the dispersion properties.For several decades, the field of spin waves gained huge interest by the scientific community due to its relevance regarding fundamental issues of spindynamics in the field of solid states physics. The ongoing research in recent years has put emphasis on the high potential of spin waves regarding information technology. In the emerging field of textit{magnonics}, several concepts for a spin-wave based logic have been proposed and realized. Opposed to charge-based schemes in conventional electronics and spintronics, magnons are charge-free currents of angular momentum, and, therefore, less subject to scattering processes that lead to heating and dissipation. This fact is highlighted by the possibility to utilize spin waves as information carriers in electrically insulating materials. These developments have propelled the quest for ways and mechanisms to guide and manipulate spin-wave transport. In particular, a lot of effort is put into the miniaturization of spin-wave waveguides and the excitation of spin waves in structures with sub-micrometer dimensions.For the further development of potential spin-wave-based devices, the ability to directly observe spin-wave propagation with spatial resolution is crucial. As an optical

  16. Multifunctional microwave photonic signal processor based on dual-parallel Mach-Zehnder modulator and stimulated Brillouin scattering

    Science.gov (United States)

    Shi, Zhan; Wang, Ling; Yang, Cheng Wu; Li, Ming; Zhu, Ning Hua; Li, Wei

    2017-09-01

    We report a multifunctional microwave photonic signal processor based on dual-parallel Mach-Zehnder modulator and stimulated Brillouin scattering. The signal processor acts as a microwave photonic filter (MPF) and microwave photonic phase shifter (MPS) simultaneously. The MPF and MPS can be tuned separately. Experimental results demonstrate that the central frequency of the bandpass MPF is tunable from 3 to 18 GHz while the MPS in the passband of the MPF is continuously adjustable over 360 deg.

  17. Stimulated Brillouin scattering in highly birefringent multimode tapered chalcogenide photonic crystal fiber for distributed optical sensors (Retraction Notice)

    Science.gov (United States)

    Baili, Amira; Cherif, Rim; Zghal, Mourad

    2016-09-01

    This paper, originally published on September 15, 2016, was retracted from the SPIE Digital Library on October 5, 2016, due to a high degree of similarity between specific portions of the text of the paper to the following publications: J. Tchahame, J. Beugnot, A. Kudlinski, and T. Sylvestre, "Multimode Brillouin spectrum in a long tapered birefringent photonic crystal fiber," Opt. Lett. 40, 4281-4284 (2015). doi: 10.1364/OL.40.004281 W. W. Ke, X. J. Wang and X. Tang, "Stimulated Brillouin Scattering Model in Multi-Mode Fiber Lasers," in IEEE Journal of Selected Topics in Quantum Electronics, vol. 20, no. 5, pp. 305-314, Sept.-Oct. 2014. doi: 10.1109/JSTQE.2014.2303256.

  18. Brillouin scattering measurements of the temperature dependence of sound velocity and acoustic absorption in simple alcohols

    Science.gov (United States)

    Stevens, J. R.; Coakley, R. W.

    2011-07-01

    A scanning Fabry-Perot interferometer was used to measure Brillouin spectra of methanol, isopropanol and a 95% ethanol-water mixture for temperatures ranging between 285 K and 320 K. The Brillouin frequency shifts and linewidths were used to calculate the velocities and absorption coefficients of hypersonic acoustic waves in these liquids. The temperature dependence of sound speed and acoustic attenuation was determined. For all three materials, both sound velocity and absorption coefficient decreased with temperature.

  19. Pilot study on rugged fiber optic brillouin sensors for large-strain measurements to ensure the safety of transportation structures.

    Science.gov (United States)

    2012-07-01

    Brillouin-scattering Optical Time Domain Reflectometry (BOTDR) is a viable technology for simultaneous, distributed : strain and temperature measurements for miles-long transportation structures. It is a promising tool to ensure the smooth : operatio...

  20. Coherent Forward Stimulated-Brillouin Scattering of a Spatially Incoherent Laser Beam in a Plasma and Its Effect on Beam Spray

    International Nuclear Information System (INIS)

    Grech, M.; Riazuelo, G.; Pesme, D.; Weber, S.; Tikhonchuk, V. T.

    2009-01-01

    A statistical model for forward stimulated-Brillouin scattering is developed for a spatially incoherent, monochromatic, laser beam propagating in a plasma. The threshold above which the laser beam spatial incoherence cannot prevent the coherent growth of forward stimulated-Brillouin scattering is computed. It is found to be well below the threshold for self-focusing. Three-dimensional simulations confirm its existence and reveal the onset of beam spray above it. From these results, we propose a new figure of merit for the control of propagation through a plasma of a spatially incoherent laser beam

  1. Interfacial Dzyaloshinskii-Moriya interaction sign in Ir/Co2FeAl systems investigated by Brillouin light scattering

    Science.gov (United States)

    Belmeguenai, M.; Gabor, M. S.; Roussigné, Y.; Petrisor, T.; Mos, R. B.; Stashkevich, A.; Chérif, S. M.; Tiusan, C.

    2018-02-01

    C o2FeAl (CFA) ultrathin films, of various thicknesses (0.9 nm ≤tCFA≤1.8 nm ), have been grown by sputtering on Si substrates, using Ir as a buffer layer. The magnetic properties of these structures have been studied by vibrating sample magnetometry (VSM), miscrostrip ferromagnetic resonance (MS-FMR), and Brillouin light scattering (BLS) in the Damon-Eshbach geometry. VSM characterizations show that films are mostly in-plane magnetized and the saturating field perpendicular to the film plane increases with decreasing CFA thickness suggesting the existence of a perpendicular interface anisotropy. The presence of a magnetic dead layer of 0.44 nm has been detected by VSM. The MS-FMR with the magnetic field applied perpendicularly to the film plane has been used to determine the gyromagnetic factor. The BLS measurements reveal a pronounced nonreciprocal spin wave propagation, due to the interfacial Dzyaloshinskii-Moriya interaction (DMI) induced by the Ir interface with CFA, which increases with decreasing CFA thickness. The DMI sign has been found to be the same (negative) as that of Pt/Co, in contrast to the ab initio calculation on Ir/Co, where it is found to be positive. The thickness dependence of the effective DMI constant shows the existence of two regimes similarly to that of the perpendicular anisotropy constant. The surface DMI constant Ds was estimated to be -0.37 pJ /m for the thickest samples, where a linear thickness dependence of the effective DMI constant has been observed.

  2. 40-gHz, 100-fs stimulated-Brillouin-scattering-free pulse generation by combining a mode-locked laser diode and a dispersion-decreasing fiber.

    Science.gov (United States)

    Hagiuda, Ken-ichi; Hirooka, Toshihiko; Nakazawa, Masataka; Arahira, Shin; Ogawa, Yoh

    2005-03-15

    A 40-GHz, 100-fs pulse train was successfully generated by soliton compression of a mode-locked laser diode (MLLD) pulse with a dispersion-decreasing fiber. The MLLD had a longitudinal mode linewidth as broad as 60 MHz, which made it possible to suppress stimulated Brillouin scattering and achieve stable, ultrahigh-speed pulse compression without applying external frequency modulation.

  3. Size-dependent magnetization dynamics in individual Ni80Fe20 disk using micro-focused Brillouin Light Scattering spectroscopy

    Directory of Open Access Journals (Sweden)

    G. Shimon

    2015-09-01

    Full Text Available A direct and systematic investigation of the magnetization dynamics in individual circular Ni80Fe20 disk of diameter (D in the range from 300 nm to 1 μm measured using micro-focused Brillouin Light Scattering (μ-BLS spectroscopy is presented. At high field, when the disks are in a single domain state, the resonance frequency of the uniform center mode is observed to reduce with reducing disk’s diameter. For D = 300 nm, additional edge and end-domains resonant modes are observed due to size effects. At low field, when the disks are in a vortex state, a systematic increase of resonant frequency of magnetostatic modes in a vortex state with the square root of the disks’ aspect ratio (thickness divided by radius is observed. Such dependence diminishes for disks with larger aspect ratio due to an increasing exchange energy contribution. Micromagnetic simulations are in excellent agreement with the experiments.

  4. OPTICAL DATA PROCESSING: Realization of associative memory with the aid of a nonlinear selective stimulated-Brillouin-scattering mirror

    Science.gov (United States)

    Matveyev, A. Z.; Pasmanik, G. A.

    1993-05-01

    An associative memory using only optical elements has been realized experimentally. The key element of the arrangement is a stimulated-Brillouin-scattering (SBS) selector consisting of a short SBS medium at the focus of a lens. The qualitative advantage of the selector over an SBS mirror is demonstrated experimentally. The response time of the arrangement is ~ 10-8 s and is determined by the duration of the SBS. Estimates show that the SBS selector is capable in practice of distinguishing a signal against background noise when the initial distortion level of the object beam is 10-3. Reliable operation of the SBS selector has been demonstrated for radiative and energy loads reaching 2 GW/cm2 and 2 J, respectively.

  5. Optical Generation of 80 GHz Downstream Data in Radio over Fiber System Based on Stimulated Brillouin Scattering

    Directory of Open Access Journals (Sweden)

    Husaini M.M.H

    2017-01-01

    Full Text Available In this work, we proposed Stimulated Brillouin Scattering (SBS in an optical generation of millimeter waves (mm-waves for radio over fiber (RoF system with the transmission of 2.5 Gbps data rate. SBS method is achieved by imposing continuous wave (CW laser in a single mode optical fiber (SMF via Mach-Zehnder Modulator (MZM with Erbium-Doped Fiber Amplifier (EDFA and two pump lasers. Mm-waves signal of 80 GHz was generated from a 40 GHz radio frequency (RF synthesizer. Simulation result and the analysis comparison of effective light power are investigated with different SMF loop length from 20 km until 120 km. The performance of SBS system is analysed and the generated of millimeter waves signal can be transmit with length up to 120 km based on eye pattern and Bit Error Rate (BER curve.

  6. Relaxation dynamics of lead-free (Na{sub 1/2}Bi{sub 1/2})TiO{sub 3}–BaTiO{sub 3} single crystals studied by Brillouin scattering

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byoung Wan [Department of Physics, Hallym University, Chuncheon, Gangwondo 24252 (Korea, Republic of); Ko, Jae-Hyeon, E-mail: hwangko@hallym.ac.kr [Department of Physics, Hallym University, Chuncheon, Gangwondo 24252 (Korea, Republic of); Li, Xiaobing; Luo, Haosu [Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2016-10-01

    The acoustic properties of 0.95(Na{sub 1/2}Bi{sub 1/2})TiO{sub 3}–0.05BaTiO{sub 3} (NBT–0.05BT) single crystals were investigated in a hypersonic frequency range and compared to those of archetypal relaxor Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} (PMN). Temperature dependences of the Brillouin frequency shift of the longitudinal acoustic (LA) mode, as well as its half width, of NBT–5%BT and PMN exhibited diffuse and broad anomalies over a wide temperature range, which were related to the softening of the sound velocity and substantial increase in the hypersonic damping toward the dielectric maximum temperature. These broad acoustic anomalies of unpoled NBT–0.05BT suggest the existence of noncentrosymmetric polar nanoregions in the paraelectric phase which do not evolve into a long-range ferroelectric order. The calculated relaxation times of NBT–0.05BT exhibited much longer values compared to those of PMN, which suggests that the size of polar nanoregions of NBT–0.05BT is larger than that of PMN.

  7. Phasing of Stokes radiation under shock excitation of stimulated Brillouin scattering

    Energy Technology Data Exchange (ETDEWEB)

    Gordeev, A A; Efimkov, V F; Zubarev, I G; Mikhailov, S I [P N Lebedev Physical Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2011-11-30

    Interaction of counterpropagating waves in Brillouin-active media has been analysed by numerical computation. The dynamics of the development of acoustic waves is described using a secondorder equation. It is shown that in the case of counterpropagating waves with sufficiently steep leading pulse edges ({tau}{sub f} {<=} 3T{sub 2}, where T{sub 2} is the acoustic phonon lifetime), SBS begins from the level of acoustic waves induced by shock excitation in the bulk of the active medium rather than from the spontaneous noise level. This mechanism determines the phase of the output Stokes wave, which is generated in the backward direction to the wave with the highest input intensity, irrespective of the ratio of counterpropagating-wave frequencies.

  8. Elastic Constants of Brucite (Mg(OH)2) and Diaspore (AlO(OH)) to 12 GPa by Brillouin Scattering

    Science.gov (United States)

    Jiang, F.; Speziale, S.; Majzlan, J.; Duffy, T. S.

    2005-12-01

    Hydroxides such as brucite, Mg(OH)2, and diaspore, AlO(OH), serve as analogs for the more complex hydrogen-bearing minerals found in subduction zones. The single-crystal elastic constants of these two minerals were determined by Brillouin scattering up to 12 GPa in a diamond anvil cell. A 16:3:1 methanol-ethanol-water and 4:1 methanol-ethanol mixture were used as pressure media and ruby as pressure calibrant. Two platelets of brucite and three platelets of diaspore were measured at room pressure and over nine elevated pressures. Brillouin spectra were recorded in 37 directions with a 5-degree step for each plane. All individual elastic stiffness constants were retrieved by fitting the velocity data to the Christoffel's equation. The individual elastic constants, aggregate bulk and shear moduli, were then fitted to the finite Eulerian stain equations to obtain their pressure derivatives. For brucite, aggregate moduli and their pressure derivatives are KT0=35.9(9) GPa, GO=31.3(2) GPa, (∂ Kt/∂ P)T0=8.9(3), (∂ G/∂ P)O=4.33(4) for the Reuss bound. Diaspore aggregate moduli and their pressure derivatives are KT0=147.0(7) GPa, GO=114.8(5) GPa, (∂ Ks/∂ P)T0=4.1(1), (∂ G/∂ P)O=1.6(1). For diaspore, both individual and aggregate elastic moduli define nearly linear modulus pressure trend within the measured pressure range. For Brucite, there are clear deviations from linear modulus - pressure trends. In comparison with diaspore, brucite exhibits strong anisotropy. The ratio of the linear compressibility of brucite along the c and a axes decreased from 4.7 to 1.3 over the examined pressure range. The shear anisotropy (C66/C44) decreased from 2.6 at ambient condition to 1.3 with increase of pressure to 12 GPa. Compression curves constructed from our Brillouin data for both brucite and diaspore are in good agreement with previous x-ray diffraction data.

  9. Stimulated Brillouin scattering phase-locking using a transient acoustic standing wave excited through an optical interference field

    International Nuclear Information System (INIS)

    Ondrej Slezak; Milan Kalal; Hon Jin Kong

    2010-01-01

    Complete text of publication follows. Analytical description of an experimentally verified scheme leading to a phase-locked stimulated Brillouin scattering (SBS), used in a laser beam combination systems, is presented. The essential condition for the phase-locking effect for SBS is the fixation of the starting position and time of the acoustic Brillouin wave. It is shown that the starting position fixation of this acoustic wave may have its origin in a transient acoustic standing wave initiated by an arising optical interference field produced by the back-seeding concave mirror. This interference field leads to a stationary density modulation of the medium. However, the way to the formation of this density modulation leads via the acoustic standing wave. An appropriate solution, in the form of the standing wave, was obtained from solving the acoustic wave-equation using the electrostriction as a driving force. As a consequence of the damping term included in this equation the acoustic standing wave becomes gradually attenuated and contrary to the undamped solution published earlier, thus constitutes a truly transient phenomenon. Using a mathematical formalism similar to that which is used for the SBS description in the case of a random phase, the coupled equations describing the phase-locked SBS were derived. Contrary to the case without the back-seeding mirror, where the wave chosen from the thermal noise background subsequently plays the role of a trigger of the stimulated process, in this case it is replaced by the transient standing wave produced as a consequence of the presence of an optical interference field arisen in the focal region of the back-seeding concave mirror.

  10. Monitoring the distributed impact wave on a concrete slab due to the traffic based on polarization dependence on stimulated Brillouin scattering

    International Nuclear Information System (INIS)

    Bao Xiaoyi; Zhang Chunshu; Li Wenhai; Eisa, M; El-Gamal, S; Benmokrane, B

    2008-01-01

    For the first time to our knowledge, distributed impact waves due to the highway traffic on concrete slabs reinforced with FRP bars are monitored in real time using stimulated Brillouin scattering. The impact wave is caused by the traffic passing on the highway pavement at high speed (>100 km h −1 ), which induced pressure on the concrete slabs, and in turn created a local birefringence change, leading to variation of the local state of polarization change (SOP). The pump and probe waves of the stimulated Brillouin scattering 'see' the SOP change and react with a decrease of the Brillouin gain or loss signal, when the pump and probe waves have the same input polarization state. The frequency difference between the pump and probe waves are locked at the static-strain-related Brillouin frequency. Optical fiber was embedded throughout the concrete pavement continuously reinforced with FRP bars in Highway 40 East, Montréal, Quebec to detect impact waves caused by cars and trucks passing on these pavements at a sampling rate of 10 kHz. A spatial resolution of 2 m was used over a sensing length of 300 m

  11. High-pressure Brillouin study on methane hydrate

    CERN Document Server

    Sasaki, S; Suwa, I; Kume, T; Shimizu, H

    2002-01-01

    Acoustic velocities and adiabatic elastic constants of structure I of methane hydrate (MH) have been determined as a function of pressure up to 0.6 GPa at 23 deg. C by the high-pressure Brillouin spectroscopy developed for a single molecular crystal. The pressure dependence of the acoustic velocities of MH is very similar to that of ice-Ih except for the longitudinal acoustic (LA) velocity. The value of the LA velocity along the (100) direction of MH at 0.02 GPa is 3.63 km s sup - sup 1 which is about 7% lower than the average of the LA velocities in the ice-Ih phase at -35.5 deg. C and atmospheric pressure.

  12. An experimental investigation of stimulated Brillouin scattering in laser-produced plasmas relevant to inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, Keith Stanley [Univ. of California, Davis, CA (United States)

    1993-02-11

    Despite the apparent simplicity of controlled fusion, there are many phenomena which have prevented its achievement. One phenomenon is laser-plasma instabilities. An investigation of one such instability, stimulated Brillouin scattering (SBS), is reported here. SBS is a parametric process whereby an electromagnetic wave (the parent wave) decays into another electromagnetic wave and an ion acoustic wave (the daughter waves). SBS impedes controlled fusion since it can scatter much or all of the incident laser light, resulting in poor drive symmetry and inefficient laser-plasma coupling. It is widely believed that SBS becomes convectively unstable--that is, it grows as it traverses the plasma. Though it has yet to be definitively tested, convective theory is often invoked to explain experimental observations, even when one or more of the theory`s assumptions are violated. In contrast, the experiments reported here not only obeyed the assumptions of the theory, but were also conducted in plasmas with peak densities well below quarter-critical density. This prevented other competing or coexisting phenomena from occurring, thereby providing clearly interpretable results. These are the first SBS experiments that were designed to be both a clear test of linear convective theory and pertinent to controlled fusion research. A crucial part of this series of experiments was the development of a new instrument, the Multiple Angle Time Resolving Spectrometer (MATRS). MATRS has the unique capability of both spectrally and temporally resolving absolute levels of scattered light at many angles simultaneously, and is the first of its kind used in laser-plasma experiments. A detailed comparison of the theoretical predictions and the experimental observations is made.

  13. Pump spectral linewidth influence on stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS) and self-termination behavior of SRS in liquids

    Energy Technology Data Exchange (ETDEWEB)

    He, Guang S.; Kuzmin, Andrey; Prasad, Paras N. [The Institute for Lasers, Photonics and Biophotonics, State University of New York, Buffalo, NY (United States)

    2016-12-15

    The threshold, temporal behavior, and conversion efficiency of stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SBS) in three liquids (benzene, hexane, and dimethyl sulfoxide) and two crystals (calcite and barium nitrate) have been investigated under three largely different spectral linewidth conditions. Pumped with 532-nm and nanosecond duration laser pulses of ≤ 0.01 cm{sup -1} linewidth, only SBS can be generated in all tested liquids with a high nonlinear reflectivity. However when the pump spectral linewidth is ∝0.07 cm{sup -1} or ∝0.8 cm{sup -1}, both SBS and SRS can be observed in benzene while only SRS can be generated in dimethyl sulfoxide; in all these cases SRS is the dominant contribution to the stimulated scattering but the efficiency values are drastically decreased due to the self-termination behavior of SRS in liquids, which arises from the thermal self-defocusing of both pump beam and SRS beam owing to Stokes-shift related opto-heating effect. In contrast, for SRS process in the two crystals, the thermal self-defocusing influence is negligible benefitting from their much greater thermal conductivity, and a higher conversion efficiency of SRS generation can be retained under all three pump conditions. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Elastic Characterization of Transparent and Opaque Films, Multilayers and Acoustic Resonators by Surface Brillouin Scattering: A Review

    Directory of Open Access Journals (Sweden)

    Giovanni Carlotti

    2018-01-01

    Full Text Available There is currently a renewed interest in the development of experimental methods to achieve the elastic characterization of thin films, multilayers and acoustic resonators operating in the GHz range of frequencies. The potentialities of surface Brillouin light scattering (surf-BLS for this aim are reviewed in this paper, addressing the various situations that may occur for the different types of structures. In particular, the experimental methodology and the amount of information that can be obtained depending on the transparency or opacity of the film material, as well as on the ratio between the film thickness and the light wavelength, are discussed. A generalization to the case of multilayered samples is also provided, together with an outlook on the capability of the recently developed micro-focused scanning version of the surf-BLS technique, which opens new opportunities for the imaging of the spatial profile of the acoustic field in acoustic resonators and in artificially patterned metamaterials, such as phononic crystals.

  15. pF3D Simulations of Large Outer-Beam Brillouin Scattering from NIF Rugby Hohlraums

    Science.gov (United States)

    Langer, Steven; Strozzi, David; Chapman, Thomas; Amendt, Peter

    2015-11-01

    We assess the cause of large outer-beam stimulated Brillouin scattering (SBS) in a NIF shot with a rugby-shaped hohlraum, which has less wall surface loss and thus higher x-ray drive than a cylindrical hohlraum of the same radius. This shot differed from a prior rugby shot with low SBS in three ways: outer beam pointing, split-pointing of the four beams within each outer-beam quadruplet, and a small amount of neon added to the hohlraum helium fill gas. We use pF3D, a massively-parallel, paraxial-envelope laser plasma interaction code, with plasma profiles from the radiation-hydrodynamics code Lasnex. We determine which change between the two shots increased the SBS by adding them one at a time to the simulations. We compare the simulations to experimental data for total SBS power, its spatial distribution at the lens, and the SBS spectrum. For each shot, we use profiles from Lasnex simulations with and without a model for mix at the hohlraum wall-gas interface. Work performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344. Release number LLNL-ABS-674893.

  16. High-input dynamic range and selectivity stimulated Brillouin scattering-based microwave photonic filter utilizing a dual-stage scheme.

    Science.gov (United States)

    Zhang, Ke; Zhong, Yibo; Ke, Changjian; Liu, Deming

    2017-09-01

    A high-input dynamic range and selectivity stimulated Brillouin scattering (SBS)-based microwave photonic filter (MPF) is proposed and experimentally demonstrated. By utilizing a pump-splitting dual-stage scheme to mitigate the gain saturation, an input dynamic range of >40  dB and a selectivity of >49  dB are achieved simultaneously for the first time, to the best of our knowledge. The bandwidth is reconfigurable from 50 MHz to 200 MHz by tailoring the Brillouin pump precisely. During the bandwidth turning, the passband ripple is maintained <1.3  dB, and the 20-dB shape factor is 1.2 for the 200-MHz case. The superior performance makes the proposed SBS-MPF one of the best candidates for microwave photonics applications.

  17. Modeling of stimulated Brillouin scattering near the critical-density surface in the plasmas of direct-drive inertial confinement fusion targets

    International Nuclear Information System (INIS)

    Maximov, A.V.; Myatt, J.; Seka, W.; Short, R.W.; Craxton, R.S.

    2004-01-01

    OAK-B135 The nonlinear propagation of laser beams, smoothed by spatial and temporal bandwidth, near the critical density surface of direct-drive inertial confinement fusion (ICF) targets has been modeled. The interplay between filamentation and forward and backward stimulated Brillouin scattering (SBS) is described in the presence of light reflected from the critical density surface and high absorption of light near the critical density. The spectrum of backscattered light develops a red shift due to SBS, which can be seeded by the reflection of light from the critical surface. The intensity of backscattered light decreases moderately as the bandwidth of smoothing by spectral dispersion (SSD) is increased

  18. ITER Plasma at Electron Cyclotron Frequency Domain: Tokamak Core Plasma Diagnostics Based on the Synergy of Stimulated Raman and Brillouin Scatterings

    Science.gov (United States)

    Stefan, V. Alexander

    2012-10-01

    A novel plasma diagnostic method is proposed based on the synergy of stimulated Raman and Brillouin scatterings. A nonlinear plasma mode is excited in a 4-wave coupling,footnotetextV. Alexander STEFAN, Nonlinear Electromagnetic Radiation Plasma Interactions, (S-U-Press, 2008). leading to the appearance of suprathermal electrons and accelerated ions at the plasma edgefootnotetextV. Alexander Stefan, Abstract: D1.00018 : ITER Plasma at Electron Cyclotron Frequency Domain: Stimulated Raman Scattering off Gould-Trivelpiece Modes and Generation of Suprathermal Electrons and Energetic Ions; Bulletin of the American Physical Society APS April Meeting 2011 Volume 56, Number 4. with the parameters directly dependent on the plasma parameters in the core of tokamak. Accordingly, plasma diagnostic in the core region, (ion temperature), can be performed by the diagnostics of suprathermal electrons and accelerated ions at the edge plasma.

  19. Advances of a Brillouin Scattering Lidar System for the Detection of Temperature Profiles in the Ocean: Laboratory Measurements and Field Test

    Science.gov (United States)

    Walther, T.; Rupp, D.; Friman, S.; Trees, C.; Fournier, G.

    2016-02-01

    Recently we have demonstrated the feasibility of remotely measuring temperature profiles in water under a laboratory environment employing our real-time Brillouin Scattering LIDAR (BSL) system. The working principle is based on the frequency and time resolved detection of the backscattered spontaneous Brillouin signal of a short light pulse fired into the ocean. The light source consists of a frequency-doubled fiber-amplified External Cavity Diode Laser (ECDL) providing high-energy, Fourier transform-limited laser pulses in the green spectral range. The Brillouin shift is detected with high accuracy (low uncertainty) by employing an edge filter based on an Excited State Faraday Anomalous Dispersion Optical Filter (ESFADOF). Time-resolution allows for the depth resolution and the frequency resolved shift is proportional to the speed of sound. Thus, the temperature profile can be extracted from the measurements. In our laboratory setup we were able to resolve water temperatures with a mean accuracy of up to 0.07 oC and a spatial resolution of 1 m depending on the amount of averaging. In order to prepare the system for a first field test under realistic conditions on the coast of the Mediterranean at CMRE in La Spezia, almost all of the components have been upgraded. This first test is planned for November 2015. We will present the above mentioned measurements, details about the upgrades and report on our experiences during this maritime field test.Ultimately, the plan is to operate the system from a mobile platform, e.g., a helicopter or vessel, in order to precisely determine the temperature of the surface mixed layer of the ocean with high spatial resolution.

  20. Surface Brillouin scattering measurement of the elastic constants of single crystal InAs{sub 0.91}Sb{sub 0.09}

    Energy Technology Data Exchange (ETDEWEB)

    Kotane, L M; Comins, J D; Every, A G [Materials Physics Research Institute, School of Physics, University of the Witwatersrand, Johannesburg, Wits 2050 (South Africa); Botha, J R, E-mail: Lesias.Kotane@wits.ac.z [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa)

    2011-01-01

    Surface Brillouin scattering of light has been used to measure the angular dependence of the Rayleigh surface acoustic wave (SAW), pseudo surface acoustic wave (PSAW) and longitudinal lateral wave (LLW) speeds in a (100)-oriented single crystal of the ternary semiconductor alloy InAs{sub 0.91}Sb{sub 0.09}. The wave speed measurements have been used to determine the room temperature values of the elastic constants C{sub 11}, C{sub 12} and C{sub 44} of the alloy. A simple and robust fitting procedure has been implemented for recovering the elastic constants, in which the merit function is constructed from explicit secular functions that determine the surface and lateral wave speeds in the [001] and [011] crystallographic directions. In the fitting, relatively larger weighting factors have been assigned to the SAW and PSAW data because of the greater precision with which the surface modes can be measured as compared with the lateral wave.

  1. Surface Brillouin scattering measurement of the elastic constants of single crystal InAs0.91Sb0.09

    International Nuclear Information System (INIS)

    Kotane, L M; Comins, J D; Every, A G; Botha, J R

    2011-01-01

    Surface Brillouin scattering of light has been used to measure the angular dependence of the Rayleigh surface acoustic wave (SAW), pseudo surface acoustic wave (PSAW) and longitudinal lateral wave (LLW) speeds in a (100)-oriented single crystal of the ternary semiconductor alloy InAs 0.91 Sb 0.09 . The wave speed measurements have been used to determine the room temperature values of the elastic constants C 11 , C 12 and C 44 of the alloy. A simple and robust fitting procedure has been implemented for recovering the elastic constants, in which the merit function is constructed from explicit secular functions that determine the surface and lateral wave speeds in the [001] and [011] crystallographic directions. In the fitting, relatively larger weighting factors have been assigned to the SAW and PSAW data because of the greater precision with which the surface modes can be measured as compared with the lateral wave.

  2. Mechanical characterisation of hydrogels using Brillouin microscopy, ultrasound and unconfined compression tests (Conference Presentation)

    Science.gov (United States)

    Wu, Pei-Jung; Kabakova, Irina V.; Song, ChengZe; Paterson, Carl; Overby, Darryl R.; Török, Peter

    2017-02-01

    Mechanical characterisation of biomaterials provides the basis for investigating disease-related changes in the biomechanical properties of living tissues and cells. Brillouin microscopy offers a non-invasive and label-free method to measure material properties. Briefly, Brillouin scattering involves energy exchange between photons and acoustic phonons, resulting in an optical frequency shift of the scattered light. This shift is proportional to the speed of sound in the material, and consequently to the longitudinal elastic modulus (M). However, it is unclear how Brillouin measurements, which characterize the mechanical response at GHz frequencies, relate to mechanical properties measured at much lower frequencies ( 1 Hz) relevant to physiological conditions. Furthermore, as most biomaterials are hydrated, it remains unclear how the relative incompressibility of water influences the acoustic wave speed so as to affect Brillouin measurements of hydrated biomaterials. In this study, we aim to establish the relationship between Brillouin frequency shift, acoustic wave speed and quasi-static elastic modulus of hydrogels of varying stiffness. Hydrogels are homogeneous and isotropic materials that mimic the poroelastic nature of biological tissues. Each measurement probes the mechanics of hydrogels in a significantly different frequency range: GHz for Brillouin imaging, MHz for ultrasound and Hz for unconfined compression tests. The acoustic wave speed falls into range from 1490 to 1533 m/s in both MHz (ultrasound) and GHz (Brillouin) frequency ranges. The quasi-static modulus correlates positively with Brillouin frequency shift, increasing from 6 to 54 kPa. All the results indicate the measurements obtained by Brillouin microscopy are capable of representing the material properties of hydrogels in quasi-static condition.

  3. Conjugation and transformation of the wave front by stimulated Brillouin scattering of vortex Laguerre - Gaussian laser modes

    International Nuclear Information System (INIS)

    Kopalkin, A V; Bogachev, V A; Dolgopolov, Yu V; Kochemasov, G G; Kulikov, S M; Maslov, N V; Starikov, F A; Sukharev, Stanislav A; Feoktistov, V V; Bagdasarov, V Kh; Denisov, N N; Malyutin, A A

    2011-01-01

    We study experimentally stimulated Brilluoin scattering (SBS) of vortex laser beams, namely, the LG 1 1 and LG 0 1 Laguerre -Gaussian modes. The wave front transformation is experimentally demonstrated in the case of SBS of the LG 1 1 laser mode, directly focused into the SBS cell, when the fundamental Gaussian mode LG 0 0 rather than the conjugate mode is selected from the Stokes beam. It is shown that optical vortices become phase conjugate by destroying the laser mode structure in the SBS cell. Phase conjugation (PC) of the LG 0 1 and LG 1 1 modes is obtained in the SBS mirror using a regular aberrator (microlens raster) in the system of laser beam focusing into the SBS cell.

  4. Development of low-temperature and high-pressure Brillouin scattering spectroscopy and its application to the solid I form of hydrogen sulphide

    CERN Document Server

    Murase, S; Sasaki, S; Kume, T; Shimizu, H

    2002-01-01

    A new experimental system has been developed for low-temperature and high-pressure Brillouin scattering measurements. The new system allows us to investigate the elastic properties of samples in a diamond anvil cell (DAC) down to liquid N sub 2 temperature (approx 80 K). In contrast to the case in our conventional technique, the optics in the system can be rotated for measuring the direction dependence of acoustic velocities of the samples in the DAC fixed in the cryostat. The new experimental technique was applied to the solid I form of hydrogen sulphide (H sub 2 S). As a result, three ratios of elastic constants to density were successfully determined at P = 3.70 GPa, T = 240 K: C sub 1 sub 1 /rho = 16.4, C sub 1 sub 2 /rho = 12.4, C sub 4 sub 4 /rho = 7.57 x 10 sup 6 m sup 2 s sup - sup 2. These values are almost the same as those obtained at room temperature.

  5. Dependence of Interfacial Dzyaloshinskii-Moriya Interaction on Layer Thicknesses in Ta /Co -Fe -B /TaOx Heterostructures from Brillouin Light Scattering

    Science.gov (United States)

    Chaurasiya, Avinash Kumar; Choudhury, Samiran; Sinha, Jaivardhan; Barman, Anjan

    2018-01-01

    The interfacial Dzyaloshinskii-Moriya interaction (IDMI) has recently drawn extensive research interest due to its fundamental role in stabilizing chiral spin textures in ultrathin ferromagnets, which are suitable candidates for future magnetic-memory devices. Here, we explore the ferromagnetic and heavy-metal layer-thickness dependence of IDMI in technologically important Ta /Co20Fe60B20/TaOx heterostructures by measuring nonreciprocity in spin-wave frequency using the Brillouin light-scattering technique. The observed value of the IDMI constant agrees with that obtained from a separate measurement of in-plane angular dependence of frequency nonreciprocity, which is also in good agreement with the theory predicted by Cortes-Ortuno and Landeros. Linear scaling behavior of IDMI with the inverse of Co-Fe-B thicknesses suggests that IDMI originates primarily from the interface in these heterostructures, whereas we observe a weak dependence of Ta thickness on the strength of IDMI. Importantly, the observed value of the IDMI constant is reasonably large by a factor of 3 compared to annealed Ta /Co -Fe -B /MgO heterostructures. We propose that the observation of large IDMI is likely due to the absence of boron diffusion towards the Ta /Co -Fe -B interface as the heterostructures are as deposited. Our detailed investigation opens up a route to designing thin-film heterostructures with the tailored IDMI constant for controlling Skyrmion-based magnetic-memory devices.

  6. Dynamics of a self-Q-switched fiber laser with a Rayleigh-stimulated Brillouin scattering ring mirror

    Science.gov (United States)

    Fotiadi, Andrei A.; Mégret, Patrice; Blondel, Michel

    2004-05-01

    Backward light scattering can cause passive Q switching in fiber lasers. We propose a self-consistent description of the laser dynamics. Our model quantitatively reproduces the temporal structure of pulsation and is also attractive for analysis of laser stability and statistics. The validity of the model is directly verified in an experiment.

  7. Observation of narrowband intrinsic spectra of Brillouin dynamic gratings.

    Science.gov (United States)

    Song, Kwang Yong; Yoon, Hyuk Jin

    2010-09-01

    We experimentally demonstrate that the reflection spectrum of a Brillouin dynamic grating in a polarization-maintaining fiber can be much narrower than the intrinsic linewidth of the stimulated Brillouin scattering, matching well with the theory of a fiber Bragg grating in terms of the linewidth and the reflectivity. A 3 dB bandwidth as narrow as 10.5 MHz is observed with the Brillouin dynamic grating generated in a 9 m uniform fiber.

  8. Development of High Spectral Resolution Technique for Registration Quasielastic Light Scattering Spectra Including Rayleigh and Brillouin Scattering as a Diagnostic Tool in Materials Characterization

    National Research Council Canada - National Science Library

    Bairamov, Bakhysh

    2004-01-01

    ...: As detailed in an on-line proposal the contractor will: 1) develop and build an optical device, fitted to a Fabry-Perot interferometer, to perform high-resolution quasieleastic light scattering spectroscopy; 2...

  9. Stimulated Brillouin processes in crystals and glasses

    International Nuclear Information System (INIS)

    Faris, G.W.; Hickman, A.P.

    1992-02-01

    The basic physics and material properties needed to describe and predict the Brillouin gain for a variety of materials have been investigated. Lawrence Livermore National Laboratory (LLNL) has identified transverse stimulated Brillouin scattering (SBS) as an important limiting mechanism in high power laser fusion systems. At sufficiently high laser intensities, SBS drives acoustic vibrations that can damage optical components. SRI has performed measurements and developed the corresponding theory for stimulated Brillouin gain spectroscopy in anisotropic crystals. Absolute Brillouin steady-state gain coefficients, linewidths, and frequency shifts have been determined at 532 nm for a number of optical materials of interest to LLNL. This knowledge can be used to select optical materials and devise suppression schemes that will allow much higher laser fluences to be used in laser fusion

  10. Light scattering studies of solids and atomic vapors

    Energy Technology Data Exchange (ETDEWEB)

    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 < or = 0.23 were investigated. Second, the observation of one-phonon resonant Raman scattering in HfS/sub 2/ is reported. The result is used to determine the position of the direct gap of HfS/sub 2/. Third, the first observation of the ..pi..-polarized one-magnon luminescence sideband of the /sup 4/T/sub lg/ (/sup 4/G) ..-->.. /sup 6/A/sub lg/(/sup 6/S) excitonic transition in antiferromagnetic MnF/sub 2/ is presented. An effective temperature of the crystal is deduced from the simultaneously observed anti-Stokes sideband emission. Multi-magnon (< or = 7) excitonic luminescence sidebands were also observed in MnF/sub 2/, KMnF/sub 2/, and RbMnF/sub 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/sub 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/sub 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.

  11. Dynamic stimulated Brillouin scattering analysis

    DEFF Research Database (Denmark)

    Djupsöbacka, A.; Jacobsen, Gunnar; Tromborg, Bjarne

    2000-01-01

    We present a new simple analysis - including the effect of spontaneous emission - of the (dynamic) influence of SBS on the detected receiver eye diagram. It applies in principle for general types of modulation formats such as the digital formats of ASK, FSK, and PSK. The analysis is formulated fo...

  12. Study of a non-ideal liquid mixture in the hydrodynamic regime. Rayleigh-Brillouin spectra, sound propagation and damping in the CH3CN-CCl4 system at the azeotropic composition

    International Nuclear Information System (INIS)

    Sassi, Paola; D'Elia, Valerio; Cataliotti, Rosario Sergio

    2003-01-01

    The hydrodynamic behaviour in the GHz frequency region has been analzsed for the non-ideal CH 3 CN-CCl 4 liquid mixture around the azeotropic composition. Rayleigh-Brillouin spectra have been measured as a function of temperature and composition, at fixed value of transferred wave vector in the 90 deg. scattering geometry, and also at different scattering angles to study dispersion with frequency of the spectral observables. These measurements have been complemented by those of refractive index, density and viscosity at the same temperatures and mole fraction values. Very interesting behaviour of the classic Brillouin spectral observables, such as the hypersonic propagation speeds and the acoustic absorption coefficients, has been revealed near the azeotropic composition of the mixture at the investigated temperatures, namely 15 deg. C, 25 deg. C, 40 deg. C and 60 deg. C. These effects have been interpreted at the light of the Mountain and Deutch theory of binary solutions and the forecast behaviour of the intermolecular forces around the azeotropic point composition of these very different molecular liquids

  13. Acoustic and relaxation behaviors of polydimethylsiloxane studied by using brillouin and dielectric spectroscopies

    Science.gov (United States)

    Lee, Byoung Wan; Ko, Jae-Hyeon; Park, Jaehoon; Shin, Dong-Myeong; Hwang, Yoon-Hwae

    2016-04-01

    The temperature dependences of the acoustic properties and the dielectric relaxation times of polydimethylsiloxane were investigated by using high-resolution Brillouin and broadband dielectric spectroscopies. The longitudinal sound velocity showed a large increase upon approaching the glass transition temperature while the acoustic absorption coefficient exhibited a maximum at ~263 K. Comparison of these results with previous ultrasonic data revealed a substantial frequency dispersion of the acoustic properties of this silicone-based elastomer. The relaxation times derived from the acoustic absorption peaks were consistent with the temperature dependence of the dielectric relaxation time of the structural a process, indicating a strong coupling between the acoustic waves and the segmental motions of the main chains.

  14. Elastic and anharmonic properties of pyridinium tetrafluoroborate ([C{sub 5}NH{sub 6}]{sup +}[BF{sub 4}]{sup -{identical_to}}PyBF{sub 4}): light scattering study of the phase transitions at various pressures

    Energy Technology Data Exchange (ETDEWEB)

    Ecolivet, C.; Beaufils, S.; Girard, A. [Groupe Matiere Condensee et Materiaux - UMR CNRS 6626, Universite de Rennes 1, Rennes (France); Czarnecki, P.; Wasicki, J.; Bobrowicz-Sarga, L. [Institute of Physics, Adam Mickiewicz University, Poznan (Poland)

    2001-07-30

    The vibrational properties of pyridinium tetrafluoroborate crystals were studied by means of Brillouin scattering at atmospheric pressure, Raman scattering and neutron diffraction under high pressure. It is shown that the elastic properties strongly reflect the molecular anisotropy of the pyridinium ions. The compressibility obtained from the Brillouin scattering study is in reasonable agreement with the results from neutron crystallography under pressure. Brillouin spectra reveal a small quasielastic component at room temperature, which is described by a coupled-susceptibilities formalism applied to the longitudinal mode and a relaxation mode. The mode Grueneisen parameters for all three phases that are found are determined from the pressure and temperature dependence of the Raman spectra and from neutron experiments. (author)

  15. Brillouin, Prof. Leon

    Indian Academy of Sciences (India)

    Home; Fellowship. Fellow Profile. Elected: 1939 Honorary. Brillouin, Prof. Leon. Date of birth: 7 August 1889. Date of death: 4 October 1969 ... Posted on 21 December 2017. ASTROPHYSICS: An Observational View of the Universe. Math Art and Design: MAD about Math, Math Education and Outreach. Math and Finance ...

  16. Self-pulsation threshold of Raman amplified Brillouin fiber cavities

    DEFF Research Database (Denmark)

    Ott, Johan Raunkjær; Pedersen, Martin Erland Vestergaard; Rottwitt, Karsten

    2009-01-01

    An implicit equation for the oscillation threshold of stimulated Brillouin scattering from Raman amplified signals in fibers with external feedback is derived under the assumption of no depletion. This is compared to numerical investigations of Raman amplification schemes showing good agreement...

  17. Stimulated Brillouin Cavity Optomechanics in Liquid Droplets

    Science.gov (United States)

    Giorgini, A.; Avino, S.; Malara, P.; De Natale, P.; Yannai, M.; Carmon, T.; Gagliardi, G.

    2018-02-01

    Liquid droplets are ubiquitous in nature wherein surface tension shapes them into perfect spheres with atomic-scale smooth surfaces. Here, we use stable droplets that cohost equatorial acoustical and optical resonances phase matched to enable the exchange of energy and momentum between sound and light. Relying on free-space laser excitation of multiple whispering-gallery modes, we harness a triple-resonant forward Brillouin scattering to stimulate optomechanical surface waves. Nonlinear amplification of droplet vibrations in the 60-70 MHz range is realized with spectral narrowing beyond the limit of material loss, thereby activating the droplet as hypersound-laser emitter.

  18. Brillouin suppression in a fiber optical parametric amplifier by combining temperature distribution and phase modulation

    DEFF Research Database (Denmark)

    Lorenzen, Michael Rodas; Noordegraaf, Danny; Nielsen, Carsten Vandel

    2008-01-01

    We demonstrate an increased gain in optical parametric amplier through suppression of stimulated Brillouin scattering by applying a temperature distribution along the fiber resulting in a reduction of the required phase modulation.......We demonstrate an increased gain in optical parametric amplier through suppression of stimulated Brillouin scattering by applying a temperature distribution along the fiber resulting in a reduction of the required phase modulation....

  19. Probing microscopic mechanical properties of hard tissues with Brillouin spectroscopy

    Science.gov (United States)

    Meng, Zhaokai; Yakovlev, Vladislav V.

    2015-02-01

    Mechanical properties of hard tissues play an important role in understanding underlying biological structures, as well as assessing the quality of artificial bone replacement materials. In this study, we employed Brillouin spectroscopy as a non-invasive approach to probe the microscopic elasticity of hard tissues, such as bones. Brillouin spectra were collected using a background free virtually imaged phased array spectrometer. As a reference, Raman spectra were also acquired for each imaging point. Experimental results reveal a positive correlation between the local concentration of the mineral content and the corresponding tissue stiffness, assessed through a Brillouin shift.

  20. Alloys studied by neutron scattering

    International Nuclear Information System (INIS)

    Morii, Yukio

    1993-01-01

    Neutron scattering study on the martensitic transformation and spinodal decomposition of alloys is described. Lattice vibration mode [110]TA 1 in various noble metal bcc-based alloys was measured. An analysis of the (110) interplanar force constants revealed a relation between the force constants and the martensite phase at low temperatures. Time resolved experiments of spinodal decomposition of MnCu were carried out to investigate how the separated (decomposed) phase grows in time. In the late regime of the decomposition, the size of the precipitate increased with a power law oft 0.37 while the crystallite grew as t 0.236 . (author)

  1. 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)

  2. Brillouin spectroscopy study of the radiation resistance of ferroelectric copolymer filled with Al2O3 and ZnO nanoparticles

    Science.gov (United States)

    Rouabah, Sawsen; Vincent, Brice; Chaabi, Abdelhafid; Rouxel, Didier; Girard, Sylvain

    2017-03-01

    Hybrid nanocomposite materials based on oxide nanoparticles incorporated in polymer matrix have been extensively studied in the last two decades. The purpose of the investigation was to study the ability of these materials to withstand radiation environments such as those encountered in nuclear power plants. Two nanocomposite polymers have been developed and characterized. They are based on a P(VDF-TrFE) matrix filled with either ZnO nanoparticles or Al2O3 nanoparticles. All nanocomposites were irradiated with two different types of particles (neutron and X-rays). For such materials, Brillouin spectroscopy can provide information on both elastic and elasto-optic variation with the radiation dose. This research points out that this technique also provides a good diagnostic of chemical and structural modifications induced by radiations.

  3. 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.

  4. Brillouin spectroscopy as a new method of screening for increased CSF total protein during bacterial meningitis.

    Science.gov (United States)

    Steelman, Zachary; Meng, Zhaokai; Traverso, Andrew J; Yakovlev, Vladislav V

    2015-05-01

    Bacterial meningitis is a disease of pronounced clinical significance, especially in the developing world. Immediate treatment with antibiotics is essential, and no single test can provide a conclusive diagnosis. It is well established that elevated total protein in cerebrospinal fluid (CSF) is associated with bacterial meningitis. Brillouin spectroscopy is a widely used optical technique for noninvasive determination of the elastic moduli of materials. We found that elevated protein levels in CSF alter the fluid elasticity sufficiently to be measurable by Brillouin spectroscopy, with model healthy and diseased fluids distinguishable to marked significance (P = 0.014), which increases with sample concentration by dialysis. Typical raw output of a 2-stage VIPA Brillouin spectrometer: inelastically scattered Brillouin peaks (arrows) and elastically scattered incident radiation (center cross). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Neutron scattering studies on soft materials

    International Nuclear Information System (INIS)

    Inoue, Rintaro; Kanaya, Toshiji

    2010-01-01

    We review recent progress of neutron scattering studies on soft matters using various techniques such as small angle neutron scattering, neutron spin echo, backscattering, time-of-flight technique, reflectivity and grazing-incident small angle neutron scattering. In the present review, we focus on functionalized polymers such as polyrotaxane, Nafion, polymer/nano composite system, and casein protein thin films, which are of great interest from both scientific and industrial viewpoints. We also state some future experiments at J-PARC. (author)

  6. Temporal evolution of stimulated Brillouin backscatter

    International Nuclear Information System (INIS)

    Hinkel, D.E.; Williams, E.A.; Berger, R.L.

    1994-01-01

    A qualitative understanding of the time dependence of stimulated Brillouin scattering (SBS) provides estimates of the amount of temporal growth that occurs in current inertial confinement fusion and short laser pulse interaction experiments when the growth is limited by the length of the experiment or by motion of the ''hot spots'' of the laser intensity pattern induced by beam smoothing. In the weak coupling limit, the instantaneous growth rate depends upon the plasma initial conditions early in time, is proportional to t -1/2 later in time, and asymptotically approaches the absolute growth rate (in the absence of damping). When the instability is strongly coupled, the growth rate depends upon the plasma initial conditions early in time but is proportional to t -1/3 later in time. When the growth rate drops to a value comparable to that of the ion acoustic frequency, the instability becomes effectively weakly coupled. The effects of damping are also discussed

  7. A small-angle neutron scattering study

    Indian Academy of Sciences (India)

    400Da [9]. Low-angle X-ray scattering [10] and neutron scattering [11] also in- dicated serum albumin to be a prolate ellipsoid. However, studies using 1H NMR indicated that a prolate structure was unlikely; rather a heart-shaped structure was proposed [12]. The shape of albumin reveals a heart-shaped molecule that can.

  8. High-resolution stimulated Brillouin gain spectroscopy in glasses and crystals

    International Nuclear Information System (INIS)

    Faris, G.W.; Jusinski, L.E.; Hickman, A.P.

    1993-01-01

    Theory and measurements are presented for stimulated Brillouin gain spectroscopy in anisotropic media. The coupling between arbitrary pump and Stokes waves and the corresponding acoustic wave is formulated in terms of the elastic displacement vector and the photoelastic tensor. A propagation equation that fully includes transient effects is obtained for the Stokes wave. In the limit of small-signal gains this propagation equation can be solved analytically, yielding expressions that relate experimentally accessible quantities to material properties. Absolute Brillouin steady-state gain coefficients, linewidths, and frequency shifts are thereby determined in a number of optical materials at 532 nm. The Brillouin gain coefficient for fused silica is measured by three techniques, providing the reference for absolute gain measurements. Quantitative agreement is found between theory and experiment for transient effects on stimulated Brillouin scattering

  9. 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

  10. Inelastic neutron scattering study of the Cs5H3(SO4)4 x 0.5H2O crystal and its deuterated analog

    International Nuclear Information System (INIS)

    Lushnikov, S.G.; Gvasaliya, S.N.; Belushkin, A.V.; Natcaniec, I.; Smirnov, L.S.; Dolbinina, V.V.; Shuvalov, L.A.

    1999-01-01

    Complete text of publication follows. Cs 5 H 3 (SO 4 ) 4 x 0.5H 2 O (PCTS) is a representative of superprotonic crystals, which have a dynamically disordered network of partially occupied hydrogen bonds in the high-temperature phase. Recent investigation of these crystals by Brillouin light scattering and neutron scattering revealed the isotopic effect: the disappearance of the high temperature phase transition in deuturated PCTS compound - Cs 5 D 3 (SO 4 ) 4 x 0.5D 2 O (DPCTS) [1]. For continuation these studies in the low temperature phase the inelastic neutron scattering (INS) was used. Experiments were carried out on NERA spectrometer (JINR, Dubna) on powdered samples of PCTS and DOTCS in the temperature range 20 - 30 K. The difference of diffraction spectra of PCTS and DPCTS with a different deuterium content was observed. Dependence of inelastic neutron scattering spectra versus deuterium concentration at different temperatures is discussed. (author)

  11. 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)

  12. 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

  13. Brillouin distributed temperature sensing system for monitoring of submarine export cables of off-shore wind farms

    Science.gov (United States)

    Marx, Benjamin; Rath, Alexander; Kolm, Frederick; Schröder, Andreas; Buntebarth, Christian; Dreß, Albrecht; Hill, Wieland

    2016-05-01

    For high-voltage cables, the maximum temperature of the insulation must never be exceeded at any location and at any load condition. The local temperatures depend not only on the cable design and load history, but also on the local thermal environment of the cable. Therefore, distributed temperature monitoring of high-voltage cables is essential to ensure the integrity of the cable at high load. Especially, the load of the export cables of wind farms varies strongly in dependence on weather conditions. In this field study, we demonstrate the measurement performance of a new, robust Brillouin distributed temperature sensing system (Brillouin-DTS). The system is based on spontaneous Brillouin scattering and does not require a fibre loop. This is essential for long submarine high-voltage cables, where normally no loop can be formed in the seabed. It is completely passively cooled and does not contain any moving or wearing parts. The instrument is dedicated for use in industrial and other rough environments. With a measuring time below 10 min, the temperature resolution is better than 1 °C for distances up to 50 km. In the field study, the submarine export cable of an off-shore wind farm has been monitored. The temperature profile of the export cable shows several hot spots, mostly located at cable joints, and also several cold spots.

  14. 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

  15. 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.)

  16. Electrospinning atactic polystyrene: A neutron scattering study

    International Nuclear Information System (INIS)

    Mohan, S; Sen, S; Mitchell, G R; Olley, R H; Davis, F J

    2009-01-01

    Electrospinning is a method used to produce nanoscale to microscale sized polymer fibres. In this study we electrospin 1:1 blends of deuterated and hydrogenated atactic-Polystyrene from N,N-Dimethylformamide for small angle neutron scattering experiments in order to analyse the chain conformation in the electrospun fibres. Small angle neutron scattering was carried out on randomly orientated fibre mats obtained using applied voltages of 10kV-15kV and needle tip to collector distances of 20cm and 30cm. Fibre diameters varied from 3μm - 20μm. Neutron scattering data from fibre samples were compared with bulk samples of the same polymer blend. The scattering data indicates that there are pores and nanovoiding present in the fibres; this was confirmed by scanning electron microscopy. A model that combines the scattering from the pores and the labelled polymer chains was used to extract values for the radius of gyration. The radius of gyration in the fibres is found to vary little with the applied voltage, but varies with the initial solution concentration and fibre diameter. The values for the radius of gyration in the fibres are broadly equivalent to that of the bulk state.

  17. 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

  18. 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...

  19. KrF laser amplifier with phase-conjugate Brillouin retroreflectors.

    Science.gov (United States)

    Gower, M C

    1982-09-01

    We have demonstrated the use of phase-conjugate stimulated Brillouin scattering mirrors to produce high-quality, short-pulse KrF laser beams from angular multiplexed and regenerative amplifiers. The mirror was also shown to isolate systems optically from amplifier spontaneous emission. Automatic alignment of targets using this mirror as a retroreflector was also demonstrated.

  20. Strongly coupled stimulated Brillouin amplification in pump-ionizing plasma

    Science.gov (United States)

    Peng, H.; Wu, Z. H.; Zuo, Y. L.; Zhou, K. N.; Wang, X. D.; Li, Q.; Zhu, H. Y.; Su, J. Q.

    2018-02-01

    Laser amplification based on strongly coupled stimulated Brillouin scattering in plasma is investigated. The pump and seed are at the same wavelength of 800 nm and the same duration of 3.5 ps, but with a different intensity. The plasma is produced by the front part of the pump via tunnel ionization from hydrogen. The hydrogen is fully ionized to eliminate small-scale density fluctuations in the plasma, so the transmission level of the seed is enhanced to 22%, and a relative amplification factor of 6 is obtained.

  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. Surface areas of fractally rough particles studied by scattering

    International Nuclear Information System (INIS)

    Hurd, A.J.; Schaefer, D.W.; Smith, D.M.; Ross, S.B.; Le Mehaute, A.; Spooner, S.

    1989-01-01

    The small-angle scattering from fractally rough surfaces has the potential to give information on the surface area at a given resolution. By use of quantitative neutron and x-ray scattering, a direct comparison of surface areas of fractally rough powders was made between scattering and adsorption techniques. This study supports a recently proposed correction to the theory for scattering from fractal surfaces. In addition, the scattering data provide an independent calibration of molecular adsorbate areas

  3. Magnetic scattering experiments

    International Nuclear Information System (INIS)

    Vettier, C.

    2001-01-01

    We discuss the relative use of neutrons and X-rays as scattering tools to probe the magnetic properties of materials. Neutron diffraction experiments continue to be the most appropriate tool to determine the magnetic structure of bulk solids. Synchrotron X-ray experiments are and will be used to investigate selectively the magnetic behaviour of different chemical species and/or electronic shells in magnetic systems. There exist some grey areas where the two probes can be used depending on the scientific problem under investigation. In particular, neutrons allow very accurate measurements of magnetic form factors, but X-rays provide a separation of the orbital momentum contribution to magnetisation. Comparisons between X-rays and neutrons studies of magnetism at surfaces are presented. Finally, one can anticipate that only inelastic neutron scattering experiments will allow the observation of magnetic excitations across the whole Brillouin zone

  4. Robust, Brillouin Active Embedded Fiber-Is-The-Sensor System in Smart Composite Structures

    Science.gov (United States)

    Yu, Chung

    1996-01-01

    Extensive review of our proposed sensing scheme, based mainly on the forward Guided Acoustic Wave Brillouin Scattering (GAWBS) with backward stimulated Brillouin scattering (sBs) as an auxiliary scheme for system fault tolerance has been completed during this project period. This preliminary study is conducted for a number of reasons. The most significant reasons lie in the essential capability of the system to measure temperature and pressure. These two measurands have been proposed to be sensed by sBs in our proposal. Temperature and pressure/strain are important measurands in structural monitoring, so that the effectiveness of sensing by sBs needs to be further examined. It has been pointed out initially that sBs shift will be dependent on temperature and pressure/strain simultaneously. The shift versus temperature or strain is linear. Now, the question is how can these two measurands be separated when sBs is used to sense an environment, in which both temperature and strain are changing simultaneously. Typical sBs shift plotted versus strain and varying temperature is shown in Fig. 1. As is clear, a fiber initially stressed will relax with rising temperature. This is verified by a displacement to the right with rising temperature of the sBs shift vs strain curves in the figure. A way to circumvent this ambiguity is by employing two fibers, one pre-stressed and the other is a free fiber. The latter will measure temperature and subtracting data in the latter fiber from those of the former will give us net strain readings. This is a laborious approach, since it involves the use of two identical fibers, and this is hard to accomplish, especially when many sensors are needed. Additional multiplexing of the data stream for data subtraction becomes a necessity.

  5. Neutron scattering at structural phase transformations

    International Nuclear Information System (INIS)

    Plakida, N.M.

    1982-01-01

    The specific fractures of neutron scattering cross sections on crystal lattices at structural phase transformations are considered in the lecture. The analysis of the elastic and inelastic scattering is carried out at different transformations (ordering type, displacement type incommensurable transformations). The experimental study on some transitions are given as an example, namely, transformation at the Brillouin zone edge in cubic perovskite. RbCaF 3 transformation in a quasiunidimensional ferroelectrics CsH 2 PO 4 and CsD 2 PO 4 , phase transformation into an incommensurable phase in diphenyl

  6. Neutron scattering studies of premartensitic phenomena

    International Nuclear Information System (INIS)

    Shapiro, S.M.

    1989-01-01

    Elastic neutron diffraction and inelastic neutron scattering are ideal techniques for studying premartensitic behavior in metallic alloys. By necessity, real, bulk samples are probed replete with their intrinsic defects. Also, because of the properties of the neutron it is straightforward to probe the behavior of the phonon modes away from the zone center which is probed in the normal ultrasonic techniques. A wide variety of alloys exhibiting martensitic transformations have been studied. It will be shown that most systems undergoing diffusionless transformations exhibit premartensitic behavior in that precursor effects are seen at temperatures well above the martensitic transformation temperature, T M . This behavior manifests itself in an anomalous temperature dependence of the energy of a particular phonon mode as the temperature approaches T M . The wavevector of this mode is frequently away from the zone center (i.e., q ≠ O). This softening is nearly always accompanied by elastic diffuse scattering at the same wavevector. Particular examples to be discussed are the alkali metals, ω-phase materials and Ni-based alloys. 34 refs., 9 figs

  7. Neutron scattering studies of carbon nanotubes

    International Nuclear Information System (INIS)

    Rols, S.; Anglaret, E.; Sauvajol, J.L.

    1999-01-01

    Complete text of publication follows. Neutron scattering is shown to be a powerful tool for the study of both the structure and the vibrational properties of nanotubes. Comparison between the neutron diffraction data and calculations on finite-size bundles of single wall carbon nanotubes (SWNT) allow to estimate the mean-tube diameter, the tube diameter distribution as well as the mean-size of the bundles. The technique is complementary of x-ray diffraction since it allows a characterization of large amount of samples. A good agreement is found with structural information obtained in electron microscopy and Raman spectroscopy. Recent results probing the evolution of the diffraction spectra of SWNT samples with temperature and pressure will be presented. Moreover, the efficiency of TOF neutron scattering is demonstrated to study the phonon density of states of SWNT. Original features are recorded in the frequency range 6 to 60 meV and assigned to intratube excitations on the basis of calculations for (10,10) SWNT. At lower frequencies (below 6 meV), a peculiar frequency-dependence is observed of the density of states assigned to some contribution due to intratube and intertube excitations with peculiar q-dispersions. Preliminary results on multi-wall nanotubes will also be presented. (author)

  8. 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)

  9. Brillouin microspectroscopy of nanostructured biomaterials: photonics assisted tailoring mechanical properties

    Science.gov (United States)

    Meng, Zhaokai; Jaiswal, Manish K.; Chitrakar, Chandani; Thakur, Teena; Gaharwar, Akhilesh K.; Yakovlev, Vladislav V.

    2016-03-01

    Developing new biomaterials is essential for the next-generation of materials for bioenergy, bioelectronics, basic biology, medical diagnostics, cancer research, and regenerative medicine. Specifically, recent progress in nanotechnology has stimulated the development of multifunctional biomaterials for tissue engineering applications. The physical properties of nanocomposite biomaterials, including elasticity and viscosity, play key roles in controlling cell fate, which underlines therapeutic success. Conventional mechanical tests, including uniaxial compression and tension, dynamic mechanical analysis and shear rheology, require mechanical forces to be directly exerted onto the sample and therefore may not be suitable for in situ measurements or continuous monitoring of mechanical stiffness. In this study, we employ spontaneous Brillouin spectroscopy as a viscoelasticity-specific probing technique. We utilized a Brillouin spectrometer to characterize biomaterial's microscopic elasticity and correlated those with conventional mechanical tests (e.g., rheology).

  10. 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)

  11. 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.)

  12. Small-angle scattering studies on clathrin-coated vesicles

    International Nuclear Information System (INIS)

    Bauer, R.; Hansen, S.; Oegendal, L.; Behan, M.; Jones, G.; Mortensen, K.; Saermark, T.

    1991-01-01

    Structural information of clathrin-coated vesicles has been achieved by small-angle X-ray, neutron and dynamic light scattering studies. A characteristic peak in the X-ray and neutron scattering profile (in D 2 O) from intact coated vesicles is consistent with the polygonic structure of the clathrin coat. Neutron as well as dynamic light scattering gives a coated vesicle size close to 1000A. Dynamic light scattering detects a distribution of sizes for the coated vesicles demonstrating polydispersity of the samples. Quick freezing and slow thawing cause breakdown of the polygonic coat and production of large aggregates, as observed by dynamic light scattering and the reduction of the peak in the X-ray scattering profile as well as an increase in the scattering intensity at the lowest angles in the neutron scattering profile. (orig.)

  13. 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.

  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. 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

  16. 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

  17. Widely tunable multiwavelength Brillouin-erbium fiber laser with triple Brillouin-shift wavelength spacing

    Science.gov (United States)

    Al-Mansoori, M. H.; Al-Sheriyani, A.; Younis, M. A. A.; Mahdi, M. A.

    2018-03-01

    In this paper, we demonstrate a widely tunable multiwavelength Brillouin-erbium fiber laser (MBEFL) having a wavelength spacing of 0.25 nm (triple Brillouin-shift wavelength spacing). The proposed laser structure overcomes the need for Brillouin pump wavelength to be closed to the self-lasing cavity modes region. The laser exhibits a wide tuning range of 40 nm (from 1530 nm to 1570 nm) at Brillouin pump and 980 nm pump powers of 25 mW and 350 mW, respectively. Four stable output channels are produced within this wavelength range with all the channels having a peak output power greater than 1.58 mW. The laser has the potential to be used as a multiwavelength laser source for dense wavelength division multiplexing communication.

  18. Experimental study of multiple scattering in anisotropic titanium alloys

    Science.gov (United States)

    Baelde, Aurelien; Laurent, Jérôme; Coulette, Richard; Khalifa, Warida Ben; Duclos, Daniel; Jenson, Frédéric; Fink, Mathias; Prada, Claire

    2017-02-01

    Ultrasonic testing of jet engine titanium alloys is of high importance for the aircraft manufacturing industry. The quality of ultrasonic non-destructive testing is severely impacted by the titanium complex microstructure. These alloys have been extensively studied and single scattering models are now well known and implemented in ultrasonic propagation simulators. In addition, titanium billets and forged parts have been known to exhibit a highly anisotropic microstructure. We studied ultrasonic wave scattering in Ti17 forged disk, through statistical analysis of the backscattered noise generated by the microstructure. More specifically, we focused on the quantification of multiple scattering relative to single scattering in the backscattered wave. To that end, we used the full matrix capture acquisition with a linear transducer array. Two phenomena were used to quantify the proportion of single scattering with respect to multiple scattering. The first is the coherent backscattering effect, used as a binary indicator of multiple scattering. The second is a repurposed version of the multiple scattering filter, recently developed on random rod forest and applied on Inconel alloys. With these methods, significant level of multiple scattering was consistently measured in Ti17 forged disks, showing that ultrasonic testing could be enhanced by filtering the multiple scattering contribution.

  19. Distributed Brillouin fiber optic strain monitoring applications in advanced composite materials

    Science.gov (United States)

    Bastianini, Filippo; Cargnelutti, Mario; Di Tommaso, Angelo; Toffanin, Massimo

    2003-08-01

    Composite materials based on glass, carbon and aramid fibers have many advantages such as fast application, lightweight and corrosion resistance, and are widely diffused for manufacturing of tanks, pipings and for restoration, upgrade and seismic retrofit of structures and historical heritage. As several questions regarding long term durability of composite strengthenings remains still unsolved, monitoring of strain and temperature is strongly recommended, respectively to assess proper load transfer and no glass phase transition of the polymeric matrix. In this research work strain and temperature distributed sensing trough Brillouin scattering in single-mode optical fibers was used in different tests in order to understand the influence of different fiber coatings and embedding techniques. Pressure tests were performed on a GFRP piping with inhomogeneous strengthening layout and Brillouin strain data were compared with conventional strain gages. A smart CFRP material has been also developed and evaluated in a seismic retrofit application on an historical building dated 1500 that was seriously damaged in the earthquake of 1997. The developed embedding technique has been demonstrated successful to obtain fiber-optic smart composites with low optical losses, and the data comparison between Brillouin and resistive strain gauges confirms Brillouin technique is very effective for composite monitoring.

  20. Multiwavelength ytterbium-Brillouin random Rayleigh feedback fiber laser

    Science.gov (United States)

    Wu, Han; Wang, Zinan; Fan, Mengqiu; Li, Jiaqi; Meng, Qingyang; Xu, Dangpeng; Rao, Yunjiang

    2018-03-01

    In this letter, we experimentally demonstrate the multiwavelength ytterbium-Brillouin random fiber laser for the first time, in the half-open cavity formed by a fiber loop mirror and randomly distributed Rayleigh mirrors. With a cladding-pumped ytterbium-doped fiber and a long TrueWave fiber, the narrow linewidth Brillouin pump can generate multiple Brillouin Stokes lines with hybrid ytterbium-Brillouin gain. Up to six stable channels with a spacing of about 0.06 nm are obtained. This work extends the operation wavelength of the multiwavelength Brillouin random fiber laser to the 1 µm band, and has potential in various applications.

  1. 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.)

  2. Future studies on electron scattering; a renaissance

    International Nuclear Information System (INIS)

    Mason, Nigel J

    2014-01-01

    2014 is the centenary of the first announcement of the Franck-Hertz experiment [1], now regarded as one of the pivotal experiments of modern physics. The Franck-Hertz experiment is widely regarded as an experiment that provided validation of the Bohr theory of atomic structure, itself only published in 2013, however it should also be viewed as the first quantitative experiment in electron scattering and the birth of scientific study of atomic and molecular phenomena by collisions. Today we recognize that electron-atom and electron- molecule collisions are prevalent across nature, describing disparate phenomena whilst the exploitation of such collisions underpins many of the technologies upon which modern society relies. The centenary of the Franck-Hertz experiment is thus a suitable opportunity to review both our current knowledge of electron interactions and to consider the directions of future research. In this article I therefore aim to both review our current state of knowledge and look forward, proposing that recent advances are providing something of a renaissance to the field and are vital for emerging technologies as well as answering some of the greatest scientific challenges of the 21st century

  3. 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.

  4. Liquid surface dynamics: a quantum-resolved scattering study

    Science.gov (United States)

    Kenyon, A. J.; McCaffery, A. J.; Quintella, C. M.; Zidan, M. D.

    1992-02-01

    Results are presented from a preliminary study of molecular scattering from liquid surfaces. Cold iodine molecules have been scattered off the surface of a methylated poly-siloxane oil and liquid gallium. Energy transfer at the liquid surface has been probed via the laser-induced fluorescence spectrum of the scattered molecules from which the vibrational and rotational state populations are accessible. We have been able to follow energy transfer via two separate channels; impulsive scattering and trapping-desorption, and have made a brief study of changes in the degree of vibrational and rotational accommodation at and around the melting point of gallium.

  5. Complex Magnetic Systems Studied with Neutron Scattering

    DEFF Research Database (Denmark)

    Jacobsen, Henrik

    was conrmed with further neutron scattering experiments. An apparent discontinuity in the dispersion of the dynamic stripes in the limit of vanishing energy transfer was found in violation of Goldstone's theorem. Detailed simulations of the experiment showed that this eect could not be explained......This thesis presents work done during my PhD jointly at the Niels Bohr Institute and the European Spallation Source. The thesis can be divided into four parts: introduction, magnetic nanoparticles, frustrated materials and superconductivity. The rst part is an introduction to magnetism and neutron....... This leads to absence of long range order even at very low temperatures and to fascinating new states of matter. Neutron scattering is the main experimental tool used in this thesis. The advantage of neutron scattering is that the neutron is sensitive to both magnetic order and magnetic dynamics...

  6. A small angle neutron scattering study

    Indian Academy of Sciences (India)

    Nanocrystalline nickel oxide powders were calcined at 300, 600 and 900°C and pore structure evolution was followed by small angle neutron scattering (SANS). Pore size distributions at two widely separated size ranges have been revealed. Shrinkage of larger-sized pore with reduction in polydispersity has been observed ...

  7. Non-local effect in Brillouin optical time-domain analyzer based on Raman amplification

    International Nuclear Information System (INIS)

    Jia Xinhong; Rao Yunjiang; Wang Zinan; Zhang Weili; Ran Zengling; Deng Kun; Yang Zixin

    2012-01-01

    Compared with conventional Brillouin optical time-domain analyzer (BOTDA), the BOTDA based on Raman amplification allows longer sensing range, higher signal-to-noise ratio and higher measurement accuracy. However, the non-local effect induced by pump depletion significantly restricts the probe optical power injected to sensing fiber, thereby limiting the further extension for sensing distance. In this paper, the coupled equations including the interaction of probe light, Brillouin and Raman pumps are applied to the study on the non-local characteristics of BOTDA based on Raman amplification. The results show that, the system error induced by non-local effect worsens with increased powers of probe wave and Raman pump. The frequency-division-multiplexing (cascading the fibers with various Brillouin frequency shifts) and time-division-multiplexing (modulating both of the Brillouin pump and probe lights) technologies are efficient approaches to suppress the non-local effect, through shortening the effective interaction range between Brillouin pump and probe lights. (authors)

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

    Indian Academy of Sciences (India)

    in a wide variety of industrial, biological, pharmaceutical and cosmetic systems. The mechanism of unfolding of proteins on addition of the surfactant has been studied by several techniques such as circular dichroism (CD), nuclear magnetic resonance (NMR), microcalorimetry, light scattering and small angle scattering.

  9. 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...

  10. Light scattering study of irradiated lipid bilayer.

    Science.gov (United States)

    Monem, A S; Blott, B H; Khalil, W A

    1992-05-01

    Vesicular phospholipid bilayer membranes in the form of giant unilamellar vesicles (GUVs) of dipalmitoylphosphatidylcholine (DPPC) were irradiated with fast neutron fluences ranging from 10(4) to 10(7) n cm-2. The phase behaviour of both non-irradiated and irradiated GUVs was investigated using an angular light scattering technique. A model independent size distribution of the samples and their optical anisotropy (delta) were determined using a maximum entropy technique and the theory of light scattering from spherical shells composed of anisotropic cylindrical molecules arranged radially in the shells. The structural changes in the lipid bilayer exposed to fission neutrons are discussed on the basis of the damaging mechanisms of fast neutrons to both the hydrophobic and hydrophilic regions of the lipid bilayer.

  11. Temperature dependence of Brillouin frequency shift in polymers controlled by plasticization effect

    Science.gov (United States)

    Minakawa, Kazunari; Koike, Kotaro; Du, Qiming; Hayashi, Neisei; Koike, Yasuhiro; Mizuno, Yosuke; Nakamura, Kentaro

    2015-04-01

    The temperature-dependence coefficient of Brillouin frequency shift (BFS) in perfluorinated graded-index polymer optical fibers is known to change drastically, because of the glass transition, at a certain critical temperature (Tc), above which the BFS becomes more sensitive to temperature. In this paper, we demonstrate that the Tc value can be adjusted by varying the dopant concentration, which is originally used to form the graded-index profile in the core region. Furthermore, we show that the temperature sensitivity of the BFS is enhanced in the presence of dopant probably because the temperature sensitivity of Young's modulus is increased. The results indicate a big potential of the temperature sensors based on Brillouin scattering with an extremely high sensitivity in a specific desired temperature range.

  12. 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....

  13. 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)

  14. 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

  15. 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

  16. A Neutron Elastic Diffuse Scattering Study of PMN

    OpenAIRE

    Xu, Guangyong; Shirane, G.; Copley, J. R. D.; Gehring, P. M.

    2003-01-01

    We have performed elastic diffuse neutron scattering studies on the relaxor Pb(Mg$_{1/3}$Nb$_{2/3}$)O$_3$ (PMN). The measured intensity distribution near a (100) Bragg peak in the (hk0) scattering plane assumes the shape of a butterfly with extended intensity in the (110) and (1$\\bar{1}$0) directions. The temperature dependence of the diffuse scattering shows that both the size of the polar nanoregions (PNR) and the integrated diffuse intensity increase with cooling even for temperatures belo...

  17. Scattering studies of large scale structures at the ultra small angle neutron scattering instrument S18

    Science.gov (United States)

    Hainbuchner, M.; Baron, M.; Lo Celso, F.; Triolo, A.; Triolo, R.; Rauch, H.

    2002-02-01

    In recent years ultra small angle neutron scattering (USANS) has developed into a powerful standard method for large scale structure investigations. The upgraded instrument S18 at the ILL's 58 MW high flux reactor is operated routinely with increasing beam time demand. The performance of the instrument and its abilities will be discussed in this paper. A peak to background ratio better than 10 5 is reached using Agamalian's tail reduction method. A q-range from 2.10 -5 up to 5.10 -2 Å-1 can be covered. This allows a clear overlap with standard pinhole SANS instruments. The new way collecting scattering data logarithmically equidistant in q-space saves measuring time. This allows measuring times of about 1.5 h for strong scattering specimens with reasonable statistics. We will present an overview of recent experiments which have been performed in co-operation with different groups from the international user community. This work comprises of structure investigations of petroliferous sedimentary rocks showing fractal scattering behaviour and time resolved USANS studies of the dynamics of hydration of cement paste. Concerning soft matter structures, Pirelli rubber nanocomposites have been investigated. In addition, time resolved measurement on a D 2O solution of a PPO-PEO-PPO block copolymer (Reverse Pluronic 25R5) and the dynamics of phase separation of methyl-hydroxy-propyl cellulose (MHPC) have been studied using a sample temperature control system.

  18. 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.

  19. S-band multi-wavelength Brillouin-Raman fiber laser utilizing fiber Bragg grating and Raman amplifier in the ring cavity

    Science.gov (United States)

    Anwar, Nur Elina; Ahmad Hambali, N. A. M.; Sohaimi, M. Syazwan; M. Shahimin, M.; A. Wahid, M. H.; Yusof, N. Roshidah; Malek, A. Zakiah

    2015-08-01

    This paper is focusing on simulation and analyzed of S-band multi-wavelength Brillouin-Raman fiber laser performance utilizing fiber Bragg grating and Raman amplifier in ring cavity by using Optisystem software. Raman amplifieraverage power model is employed for signal amplification. This laser system is operates in S-band wavelength region due to vast demanding on transmitting the information. Multi-wavelength fiber lasers based on hybrid Brillouin-Raman gain configuration supported by Rayleigh scattering effect have attracted significant research interest due to its ability to produced multi-wavelength signals from a single light source. In multi-wavelength Brillouin-Raman fiber, single mode fiber is utilized as the nonlinear gain medium. From output results, 90 % output coupling ratio has ability to provide the maximum average output power of 43 dBm at Brillouin pump power of 20 dBm and Raman pump power of 14 dBm. Furthermore, multi-wavelength Brillouin-Raman fiber laser utilizing fiber Bragg grating and Raman amplifier is capable of generated 7 Brillouin Stokes signals at 1480 nm, 1510 nm and 1530 nm.

  20. 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)

  1. 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

  2. The electromagnetic Brillouin precursor in one-dimensional photonic crystals

    NARCIS (Netherlands)

    Uitham, R.; Hoenders, B. J.

    2008-01-01

    We have calculated the electromagnetic Brillouin precursor that arises in a one-dimensional photonic crystal that consists of two homogeneous slabs which each have a single electron resonance. This forerunner is compared with the Brillouin precursor that arises in a homogeneous double-electron

  3. 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)

  4. Mechanical spectra of glass-forming liquids. II. Gigahertz-frequency longitudinal and shear acoustic dynamics in glycerol and DC704 studied by time-domain Brillouin scattering

    DEFF Research Database (Denmark)

    Klieber, Christoph; Hecksher, Tina; Pezeril, Thomas

    2013-01-01

    This paper presents and discusses the temperature and frequency dependence of the longitudinal and shear viscoelastic response at MHz and GHz frequencies of the intermediate glass former glycerol and the fragile glass former tetramethyl-tetraphenyl-trisiloxane (DC704). Measurements were performed...... of the shear acoustic relaxation time agrees well with literature data for dielectric measurements. In DC704, combining the new data with data from measurements obtained previously by piezo-ceramic transducers yields figures showing the longitudinal and shear sound velocities at frequencies from mHz to GHz...

  5. Quasi-elastic neutron scattering studies of protein dynamics

    International Nuclear Information System (INIS)

    Rorschach, H.E.

    1993-01-01

    Results that shed new light on the study of protein dynamics were obtained by quasi-elastic neutron scattering. The triple axis instrument H-9 supplied by the cold source was used to perform a detailed study of the quasi-elastic spectrum and the Debye-Waller factor for trypsin in powder form, in solution, and in crystals. A preliminary study of myoglobin crystals was also done. A new way to view the results of quasi-elastic scattering experiments is sketched, and the data on trypsin are presented and analyze according to this new picture

  6. Comparative full-band Monte Carlo study of Si and Ge with screened pseudopotential-based phonon scattering rates

    Science.gov (United States)

    Nguyen, Phuong Hoa; Hofmann, Karl R.; Paasch, Gernot

    2003-07-01

    In a previous article [J. Appl. Phys. 92, 5359 (2002)], we presented a combination of a full-band Monte Carlo method using an advanced band structure and a variable Brillouin zone discretization, with phonon scattering rates based on the screened pseudopotential considering the positions of the atoms in the elementary cell. To make the method suitable for sufficiently fast applications, such as device simulations, the simplest wave number dependent approximation was introduced. It contains an average of the cell structure factor, and only two fit parameters: The acoustic and the optical deformation potentials. As the pseudopotential, the Ashcroft model potential is chosen, and screening is taken into account using the Lindhard dielectric function. In the present article, based on the study of the influence of the two deformation potentials on the electron and hole drift velocities in Si and Ge, we show how to select the deformation potentials. Depending on the targeted agreement with experimental results, the pairs of deformation potentials for electrons and holes can be used uniformly for a wide temperature range or separately for different temperatures. For Ge, we achieve remarkable quantitative agreement with the temperature, field, and orientation dependencies of experimental electron and hole drift velocities in the wide temperature range from 77 to 300 K with a single set of the two deformations potentials for each carrier type. A detailed comparative simulation of the transport properties in Ge and Si at different temperatures is presented which is comprised of the steady-state dependence of the drift velocity on the electric field, the low-field mobility, and transient transport. Peculiarities of the drift velocity-field dependencies, such as the anisotropy, and a negative differential mobility are discussed in terms of the different band structures in connection with the field dependence of the simulated distribution functions. For doped materials, ionized

  7. 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...

  8. Neutron scattering studies of nanomagnetism and artificially structured materials

    International Nuclear Information System (INIS)

    Fitzsimmons, M.R.; Bader, S.D.; Borchers, J.A.; Felcher, G.P.; Furdyna, J.K.; Hoffmann, A.; Kortright, J.B.; Schuller, Ivan K.; Schulthess, T.C.; Sinha, S.K.; Toney, M.F.; Weller, D.; Wolf, S.

    2004-01-01

    Nanostructured magnetic materials are intensively investigated due to their unusual properties and promise for possible applications. The key issue for these materials is to understand the limits between their physical properties (transport, magnetism, mechanical, etc.) and their chemical-physical structure. In principle, a detailed knowledge of the chemical and physical structures allows calculation of their physical properties. Theoretical and computational methods are rapidly evolving so that magnetic properties of nanostructured materials might soon be predicted. Success in this endeavor requires detailed quantitative understanding of magnetic structure at the microscopic level. Neutron scattering is a well-developed technique that can determine magnetic structure at the atomic length scale in samples of ever diminishing size. This has opened up the use of neutron scattering to nanostructured materials prepared by thin film and lithographic techniques. Many interesting and unexpected results have emerged from the application of elastic neutron scattering to nanostructured magnetic thin films such as superlattices and multilayers. These include, distinguishing between magnetic and chemical boundaries, observing the spatial dependence of the magnetization vector in nonuniform materials, unusual coupling mechanisms across nonmagnetic materials, unexpected magnetic phase diagrams, etc. Extension of elastic neutron scattering to nanostructured arrays and three-dimensional magnetic composites will allow future determination of magnetic structure with unprecedented resolution. In this review, we discuss the impact of neutron scattering to the study of magnetic nanostructures, i.e., magnetic materials that are artificially structured at nanometer length scales, such as magnetic thin films, multilayers and nanodot arrays. The basic interactions and different length scales relevant to these systems as well as the basic issues and phenomena of interest are briefly

  9. Neutron scattering studies of nanomagnetism and artificially structured materials

    Science.gov (United States)

    Fitzsimmons, M. R.; Bader, S. D.; Borchers, J. A.; Felcher, G. P.; Furdyna, J. K.; Hoffmann, A.; Kortright, J. B.; Schuller, Ivan K.; Schulthess, T. C.; Sinha, S. K.; Toney, M. F.; Weller, D.; Wolf, S.

    2004-04-01

    Nanostructured magnetic materials are intensively investigated due to their unusual properties and promise for possible applications. The key issue for these materials is to understand the limits between their physical properties (transport, magnetism, mechanical, etc.) and their chemical-physical structure. In principle, a detailed knowledge of the chemical and physical structures allows calculation of their physical properties. Theoretical and computational methods are rapidly evolving so that magnetic properties of nanostructured materials might soon be predicted. Success in this endeavor requires detailed quantitative understanding of magnetic structure at the microscopic level. Neutron scattering is a well-developed technique that can determine magnetic structure at the atomic length scale in samples of ever diminishing size. This has opened up the use of neutron scattering to nanostructured materials prepared by thin film and lithographic techniques. Many interesting and unexpected results have emerged from the application of elastic neutron scattering to nanostructured magnetic thin films such as superlattices and multilayers. These include, distinguishing between magnetic and chemical boundaries, observing the spatial dependence of the magnetization vector in nonuniform materials, unusual coupling mechanisms across nonmagnetic materials, unexpected magnetic phase diagrams, etc. Extension of elastic neutron scattering to nanostructured arrays and three-dimensional magnetic composites will allow future determination of magnetic structure with unprecedented resolution. In this review, we discuss the impact of neutron scattering to the study of magnetic nanostructures, i.e., magnetic materials that are artificially structured at nanometer length scales, such as magnetic thin films, multilayers and nanodot arrays. The basic interactions and different length scales relevant to these systems as well as the basic issues and phenomena of interest are briefly

  10. 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)

  11. 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

  12. Instrumental resolution effects in neutron scattering studies of protein dynamics

    Science.gov (United States)

    Nickels, Jonathan D.

    2013-10-01

    In this study, the dynamics of Green Fluorescent protein (GFP) are analyzed using three neutron scattering spectrometers. We focus on the effect of instrumental energy resolution in the analysis of the elastic incoherent structure factor (EISF) and mean square displacement (MSD). This topic still remains a source of controversy. Our data clearly demonstrate the presence of the resolution effect in the dynamic transition for hydrated protein and the onset of translational motions in hydration water consistent with previous results from quasielastic neutron scattering. The 190 K onset of motions in hydration water observed at ∼1 ns is also consistent with a Tg of hydration water below 190 K.

  13. 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

  14. Superionic conductors - results from neutron scattering studies

    International Nuclear Information System (INIS)

    Banhatti, Radha D.

    2000-01-01

    Superionic conductors, exhibit electrical conductivity (σ) via ionic conduction that can be as high as 10 -1 S/cm. This enhanced conductivity is found normally after a structural phase transition from an insulating phase (10 -4 S/cm) to a more symmetric phase. In this paper, we review the results based on these studies on some superionic conductors in detail

  15. Neutron scattering study on amorphous magnetics

    International Nuclear Information System (INIS)

    Toperverg, B.P.

    1982-01-01

    The study on the ferromagnetic metallic glasses by means of neutron ssattering method is reviewed. Disordered ferromagnetics are considered with allowance for exchange interactione anisotropic interaction being neglected. Phase transformations in the systemS are discussed as well as the existence of the spin glass state from the data of various neutron experiments. The validity of the Sherrington-Kirkpatric state diagram is analyzed

  16. Dynamic light scattering study of peanut agglutinin: Size, shape and ...

    Indian Academy of Sciences (India)

    MADU

    The generation of two species is evident from the profile of hydrodynamic radii. This study also .... radii (figure 3) shows generation of intermediate species along with denatured state from 2 M urea onwards .... Quasi-elastic light scattering from human alpha-lactalbumin: comparison of molecular dimensions in native and ...

  17. Inelastic neutron scattering and lattice dynamics studies in complex ...

    Indian Academy of Sciences (India)

    At Trombay, lattice dynamics studies employing coherent inelastic neutron scattering (INS) experiments have been carried out at the two research reactors, CIRUS and Dhruva. While the early work at CIRUS involved many elemental solids and ionic molecular solids, recent experiments at Dhruva have focussed on certain ...

  18. Small angle neutron scattering study of mixed micelles of oppositely ...

    Indian Academy of Sciences (India)

    - methylammonium bromide (DTAB) and sodium dodecyl sulphate (SDS) have been studied using small angle neutron scattering. The concentration of one of the components was kept fixed (0.3 M) and that of another varied in the range 0 to ...

  19. 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

  20. Quasi-elastic laser light scattering study of polyacrylamide hydrogel ...

    Indian Academy of Sciences (India)

    Quasi-elastic laser light scattering study of polyacrylamide hydrogel immersed in water and salt solutions. M Sivanantham B V R Tata. Conributed Papers Volume 75 Issue 6 December 2010 pp 1209-1214 ... The value of the plateau was found to depend on NaCl concentration and was higher than that of water. Collective ...

  1. Small angle neutron scattering study of two nonionic surfactants in ...

    Indian Academy of Sciences (India)

    cO Indian Academy of Sciences. Vol. 71, No. 5. — journal of. November 2008 physics pp. 1079–1083. Small angle neutron scattering study of two nonionic surfactants in water micellar solutions. RAJEWSKA ALDONA. Institute of Atomic Energy, 05-400 Swierk-Otwock, Poland. E-mail: aldonar@cyf.gov.pl. Abstract.

  2. 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 ...

  3. 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.

  4. Quasi-elastic neutron scattering study of dynamics in condensed ...

    Indian Academy of Sciences (India)

    S MITRA and R MUKHOPADHYAY. Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India. E-mail: smitra@apsara.barc.ernet.in. Abstract. Quasi-elastic neutron scattering (QENS) technique, known to study stochas- tic motions has been successfully used to elucidate the molecular motions ...

  5. Ultra Small-Angle Neutron Scattering Study of Porous Glass

    International Nuclear Information System (INIS)

    Desai, Reshma R.; Desa, J. A. Erwin; Sen, D.; Mazumder, S.

    2011-01-01

    Compacts of silica micro-spheres prepared for different times at sintering temperatures of 640 deg. C and 740 deg. C have been studied by Ultra Small-Angle Neutron Scattering (USANS) and Scanning Electron Microscopy (SEM). Stress versus strain measurements display several breakage points related to a range of nearest neighbour coordination around each microsphere.

  6. Nonlinear optical absorption and stimulated Mie scattering in metallic nanoparticle suspensions.

    Science.gov (United States)

    He, Guang S; Law, Wing-Cheung; Baev, Alexander; Liu, Sha; Swihart, Mark T; Prasad, Paras N

    2013-01-14

    The nonlinear optical properties of four metallic (Au-, Au/Ag-, Ag-, and Pt-) nanoparticle suspensions in toluene have been studied in both femtosecond and nanosecond regimes. Nonlinear transmission measurements in the femtosecond laser regime revealed two-photon absorption (2PA) induced nonlinear attenuation, while in the nanosecond laser regime a stronger nonlinear attenuation is due to both 2PA and 2PA-induced excited-state absorption. In the nanosecond regime, at input pump laser intensities above a certain threshold value, a new type of stimulated (Mie) scattering has been observed. Being essentially different from all other well known molecular (Raman, Brillouin) stimulated scattering effects, the newly observed stimulated Mie scattering from the metallic nanoparticles exhibits the features of no frequency shift and low pump threshold requirement. A physical model of induced Bragg grating initiated by the backward Mie scattering from metallic nanoparticles is proposed to explain the gain mechanism of the observed stimulated scattering effect.

  7. Studying Dust Scattering Halos with Galactic X-ray Binaries

    Science.gov (United States)

    Beeler, Doreen; Corrales, Lia; Heinz, Sebastian

    2018-01-01

    Dust is an important part of the interstellar medium (ISM) and contributes to the formation of stars and planets. Since the advent of modern X-ray telescopes, Galactic X-ray point sources have permitted a closer look at all phases of the ISM. Interstellar metals from oxygen to iron — in both gas and dust form — are responsible for absorption and scattering of X-ray light. Dust scatters the light in a forward direction and creates a diffuse halo image surrounding many bright Galactic X-ray binaries. We use all the bright X-ray point sources available in the Chandra HETG archive to study dust scattering halos from the local ISM. We have described a data analysis pipeline using a combination of the data reduction software CIAO and Python. We compare our results from Chandra HETG and ACIS-I observations of a well studied dust scattering halo around GX 13+1, in order to characterize any systematic errors associated with the HETG data set. We describe how our data products will be used to measure ISM scaling relations for X-ray extinction, dust abundance, and dust-to-metal ratios.

  8. 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.)

  9. Fabry-Perot spectrometer for high resolution light scattering investigations

    International Nuclear Information System (INIS)

    Deniz, K.U.; Parvathanathan, P.S.; Paranjpe, A.S.

    1976-01-01

    A Fabry-Perot spectrometer designed specially for carrying out Brillouin scattering experiment is described in detail. The instrument has free spectral range in the domain of frequencies 1 - 10 GHz and resolution widths in the range of 30 MHz - 3 GHz. The signal to noise ratio has been improved by a factor of about 10 3 by : (1) cooling the photomultiplier detector and (2) the use of magnetic defocussing techniques. With the use of a single frequency laser source, accurate determination of Brillouin frequency shifts and of Brillouin line shapes can be made with this spectrometer. Some preliminary results obtained with a few simple liquids, are discussed. (author)

  10. A Brillouin smart FRP material and a strain data post processing software for structural health monitoring through laboratory testing and field application on a highway bridge

    Science.gov (United States)

    Bastianini, Filippo; Matta, Fabio; Galati, Nestore; Nanni, Antonio

    2005-05-01

    Strain and temperature sensing obtained through frequency shift evaluation of Brillouin scattered light is a technology that seems extremely promising for Structural Health Monitoring (SHM). Due to the intrinsic distributed sensing capability, Brillouin can measure the deformation of any individual segment of huge lengths of inexpensive single-mode fiber. In addition, Brillouin retains other typical advantages of Fiber Optic Sensors (FOS), such as harsh environment durability and interference rejection. Despite these advantages, the diffusion of Brillouin for SHM is constrained by different factors, such as the high equipment cost, the commercial unavailability of specific SHM oriented fiber products and even some prejudices on the required sensitivity performances. In the present work, a complete SHM pilot application was developed, installed and successfully operated during a diagnostic load test on the High Performance Steel (HPS) bridge A6358 located at the Lake of the Ozarks (Miller County, MO, USA). Four out of five girders were extensively instrumented with a "smart" Glass Fiber Reinforced Polymer (GFRP) tape having embedded fibers for strain sensing and thermal compensation. Data collected during a diagnostic load test were elaborated through a specific post-processing software, and the strain profiles retrieved were compared to traditional strain gauges and theoretical results based on the AASHTO LRFD Bridge Design Specifications for structural assessment purposes. The excellent results obtained confirm the effectiveness of Brillouin SHM systems for the monitoring of real applications.

  11. Raman scattering study of rare-earth hexaboride

    Science.gov (United States)

    Ogita, N.; Nagai, S.; Udagawa, M.; Iga, F.; Sera, M.; Oguchi, T.; Akimitsu, J.; Kunii, S.

    2005-04-01

    The excitation-energy, polarization, pressure, and temperature dependences of Raman scattering spectra have been measured for the RB6 crystals ( R=Ca, La, Ce, Pr, Sm, Gd, Dy, and Yb). In the Raman spectra, the extra peaks have been clearly observed at around 200 cm-1, except for the Raman-active phonons and CEF excitations. The extra peaks show anomalous behavior in the temperature, polarization, and lattice parameter dependences. These anomalous behaviors originate from the vibration of the rare-earth ions in octahedral B 6 cage, and the extra peaks can be assigned as the second-order Raman excitations of T 1u[3]. To check the validity of our assignment, we have measured the pressure dependence. In this paper, the results of the “ extra peaks” at about 200 cm -1, and pressure dependence of SmB 6 are presented. The sample preparation and experimental details are explained in our previous report [3]. The Pm3m symmetry of RB 6 gives us the phonon numbers at Brilloiun zone center; Γ=A1g+Eg+T1g+T2g+3T1u+T2u. The Raman-active phonons are A1g, Eg, and T2g, which are the vibration of boron octahedra. In cubic symmetry, all Raman-active phonons appear in the (x+y,x+y) polarization geometry. In the notation of (x,y), x and y denote the polarization directions of incident and scattered light, respectively. x and y correspond to the crystal axes of [1 0 0] and [0 1 0], respectively. Fig. 1 shows the Raman spectra of trivalent RB6 at room temperature in the energy region below T2g phonons ( ≃700 cm-1). Each spectrum is depicted in the order of the decreasing lattice parameters from top to bottom. As shown in Fig. 1, the energy of T2g phonon decreases with increasing lattice parameter, and this is normal dependence. However, the extra peaks (arrows) show an anti-trend for T2g phonon's. Focusing on the size of cage space consisting of surrounding borons for rare earth ion a-rR( a and rR are lattice parameter and ionic radius, respectively), the energy of the peaks is

  12. Small angle neutron scattering study of Linde 80 RPV welds

    International Nuclear Information System (INIS)

    Wirth, B.D.; Odette, G.R.; Lucas, G.E.; Spooner, S.E.

    1999-01-01

    Small angle neutron scattering (SANS) results are presented for Linde 80 welds irradiated, as part of the B and W Owners Group Integrated Surveillance Program, at low fluxes ( 15 n/m 2 -s) to fluences from 0.29 to 3.5 x 10 23 n/m 2 (E > 1 MeV) at irradiation temperatures from 276 to 292 C. The welds all contain about 0.6 Ni (all composition units are in wt.%), 0.009 to 0.18 P and 0.05 to 0.28 Cu. In the welds with significant amounts of copper (>0.2 Cu) the measured defect scattering cross sections were consistent with either: (a) copper rich precipitates (CRPs) alloyed with manganese and nickel; or (b) dominant CRP scattering, plus a weak contribution from so-called matrix defect features. Similar weak scattering was observed in a low copper (0.06 Cu) weld. The identity of matrix defect features cannot be determined from the SANS data alone, but the scattering is consistent with the presence of subnanometer vacancy cluster-solute complexes. The general character of the CRPs, and the trends in their number density, volume fraction and average radius as a function of fluence and irradiation temperature, are very similar to those observed in a wide range of pressure vessel-type steels irradiated in test reactors at intermediate to high flux. The SANS data in the surveillance welds is also in unity with: (a) thermodynamic-kinetic radiation enhanced diffusion models of CRP evolution; (b) mechanical property changes, including predictions of the correlations of the surveillance data base; and (c) an atomic scale, atom probe field ion microscopy study into the nanostructure-chemistry of a CRP

  13. Experimental studies of the liquid-glass transition in trimethylheptane

    Science.gov (United States)

    Shen, G. Q.; Toulouse, J.; Beaufils, S.; Bonello, B.; Hwang, Y. H.; Finkel, P.; Hernandez, J.; Bertault, M.; Maglione, M.; Ecolivet, C.; Cummins, H. Z.

    2000-07-01

    The molecular glass former trimethylheptane was studied by calorimetric, dielectric, ultrasonic, neutron scattering, Brillouin scattering, and depolarized light-scattering techniques. The molecular structure appears to be nearly spherical optically as indicated by the low depolarization ratio and dielectric susceptibility values. A preliminary mode-coupling theory (MCT) analysis of the light-scattering and neutron-scattering data indicates that TC>~150 K, at least 25 K above TG. The susceptibility minima were analyzed with the MCT interpolation equation, and disagreement between the light and neutron results was observed despite the apparent isotropy of the molecules.

  14. Neutron Scattering Studies of Thermoelectric Materials for Automotive Applications

    Science.gov (United States)

    Yang, Jihui

    2010-03-01

    Solid-state thermoelectric (TE) technology uses electrons and holes as the working fluid for heat pumping and power generation, and has the virtues of no moving parts and high reliability. Advances in TE materials can lead to high thermal-to-electrical energy conversion efficiency and hence significant energy savings by generating electricity from waste heat. A good TE material should simultaneously possess high thermopower, low electrical resistivity, and low thermal conductivity. Most of the work in the past decade has been focused on lowering materials lattice thermal conductivity. Neutron diffraction and inelastic neutron scattering provide unique opportunities to understand the vibrational properties of thermoelectric materials. I will review some of our recent neutron studies on skutterudites, prospective high efficiency TE materials. Our studies have attempted to elucidate the crucial factors in these compounds relating to the filling-atom sublattices, particularly with respect to composition, nature of mixed fillers, dynamic disorder, phase coherence, and phonon scattering mechanisms.

  15. Inelastic neutron scattering and lattice dynamics studies in complex solids

    International Nuclear Information System (INIS)

    Rao, Mala N.; Mittal, R.; Choudhury, Narayani; Chaplot, S.L.

    2004-01-01

    At Trombay, lattice dynamics studies employing coherent inelastic neutron scattering (INS) experiments have been carried out at the two research reactors, CIRUS and Dhruva. While the early work at CIRUS involved many elemental solids and ionic molecular solids, recent experiments at Dhruva have focussed on certain superconductors (cuprates and intermetallics), geophysically important minerals (Al 2 SiO 5 , ZrSiO 4 , MnCO 3 ) and layered halides (BaFCl, ZnCl 2 ). In most of the studies, theoretical modelling of lattice dynamics has played a significant role in the interpretation and analysis of the results from experiments. This talk summarises the developments and current activities in the field of inelastic neutron scattering and lattice dynamics at Trombay. (author)

  16. 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.)

  17. 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.

  18. Application of Coupled-Wave Wentzel-Kramers-Brillouin Approximation to Ground Penetrating Radar

    Directory of Open Access Journals (Sweden)

    Igor Prokopovich

    2017-12-01

    Full Text Available This paper deals with bistatic subsurface probing of a horizontally layered dielectric half-space by means of ultra-wideband electromagnetic waves. In particular, the main objective of this work is to present a new method for the solution of the two-dimensional back-scattering problem arising when a pulsed electromagnetic signal impinges on a non-uniform dielectric half-space; this scenario is of interest for ground penetrating radar (GPR applications. For the analytical description of the signal generated by the interaction of the emitted pulse with the environment, we developed and implemented a novel time-domain version of the coupled-wave Wentzel-Kramers-Brillouin approximation. We compared our solution with finite-difference time-domain (FDTD results, achieving a very good agreement. We then applied the proposed technique to two case studies: in particular, our method was employed for the post-processing of experimental radargrams collected on Lake Chebarkul, in Russia, and for the simulation of GPR probing of the Moon surface, to detect smooth gradients of the dielectric permittivity in lunar regolith. The main conclusions resulting from our study are that our semi-analytical method is accurate, radically accelerates calculations compared to simpler mathematical formulations with a mostly numerical nature (such as the FDTD technique, and can be effectively used to aid the interpretation of GPR data. The method is capable to correctly predict the protracted return signals originated by smooth transition layers of the subsurface dielectric medium. The accuracy and numerical efficiency of our computational approach make promising its further development.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. Neutron and light scattering studies of polymers adsorbed on laponite

    CERN Document Server

    Nelson, A R J

    2002-01-01

    The adsorption of poly(ethylene oxide) (PEO) and various poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (Pluronic) copolymers onto the synthetic clay Laponite, was investigated using Small Angle Neutron Scattering (SANS) and Dynamic Light Scattering (DLS). The Laponite particles are anisotropic, with a relatively high aspect ratio; but are the same order of magnitude in size as the polymer radius of gyration. Consequently, the particles present a radically different adsorption geometry compared to a locally planar interface, that is assumed by the majority of adsorption studies. The PEO homo-polymer formed thin layers, with the layer thickness being much smaller on the face than on the edge of the particle. Furthermore, the face thickness remained constant with increasing molecular weight, unlike the edge thickness, which grew with a small power law dependence on the molecular weight. Although the hydrodynamic thicknesses (DLS) were larger than those observed with SANS, the layer thicknesses ...

  4. 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

  5. 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.

  6. 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.

  7. Neutron and Synchrotron X-Ray Scattering Studies of Superconductors

    International Nuclear Information System (INIS)

    Tranquada, J.M.

    2008-01-01

    Superconductors hold the promise for a more stable and efficient electrical grid, but new isotropic, high-temperature superconductors are needed in order to reduce cable manufacturing costs. The effort to understand high-temperature superconductivity, especially in the layered cuprates, provides guidance to the search for new superconductors. Neutron scattering has long provided an important probe of the collective excitations that are involved in the pairing mechanism. For the cuprates, neutron and x-ray diffraction techniques also provide information on competing types of order, such as charge and spin stripes, that appear to be closely connected to the superconductivity. Recently, inelastic x-ray scattering has become competitive for studying phonons and may soon provide valuable information on electronic excitations. Examples of how these techniques contribute to our understanding of superconductivity are presented

  8. Evaluating biomechanical properties of murine embryos using Brillouin microscopy and optical coherence tomography

    Science.gov (United States)

    Raghunathan, Raksha; Zhang, Jitao; Wu, Chen; Rippy, Justin; Singh, Manmohan; Larin, Kirill V.; Scarcelli, Giuliano

    2017-08-01

    Embryogenesis is regulated by numerous changes in mechanical properties of the cellular microenvironment. Thus, studying embryonic mechanophysiology can provide a more thorough perspective of embryonic development, potentially improving early detection of congenital abnormalities as well as evaluating and developing therapeutic interventions. A number of methods and techniques have been used to study cellular biomechanical properties during embryogenesis. While some of these techniques are invasive or involve the use of external agents, others are compromised in terms of spatial and temporal resolutions. We propose the use of Brillouin microscopy in combination with optical coherence tomography (OCT) to measure stiffness as well as structural changes in a developing embryo. While Brillouin microscopy assesses the changes in stiffness among different organs of the embryo, OCT provides the necessary structural guidance.

  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. 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

  12. 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

  13. Neutron scattering from an imperfect flux-line lattice

    International Nuclear Information System (INIS)

    Brandt, E.H.

    1978-01-01

    The diffraction of neutrons from the imperfect vortex lattice of a type-II superconductor is investigated. It is found that flux pinning leads not only to a broadening of the Bragg reflections but also to diffuse scattering into the first Brillouin zone, which at high fields exceeds Bragg scattering

  14. Brillouin Corrosion Expansion Sensors for Steel Reinforced Concrete Structures Using a Fiber Optic Coil Winding Method

    Directory of Open Access Journals (Sweden)

    Xingjun Lv

    2011-11-01

    Full Text Available In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

  15. Brillouin spectroscopy reveals changes in muscular viscoelasticity in Drosophila POMT mutants

    Science.gov (United States)

    Meng, Zhaokai; Baker, Ryan; Panin, Vladislav M.; Yakovlev, Vladislav V.

    2015-03-01

    Muscular dystrophy (MD) is a group of muscle diseases that induce weakness in skeletal muscle and cause progressive muscle degeneration. The muscular mechanical properties (i.e., viscoelasticity), however, have not been thoroughly examined before and after MD. On the other hand, Brillouin spectroscopy (BS) provides a non-invasive approach to probing the local sound speed within a small volume. Moreover, recent advances in background-free Brillouin spectroscopy enable investigators to imaging not only transparent samples, but also turbid ones. In this study, we investigated the mechanical properties of muscles while employing Drosophila model of dystroglycanopathies, human congenital muscular dystrophies resulting from abnormal glycosylation of alphadystroglycan. Specifically, we analyzed larval abdominal muscles of Drosophila with mutations in protein Omannosyltransferase (POMT) genes. As a comparison, we have also examined muscular tissues dissected from wildtype Drosophila. The Brillouin spectra were obtained by a background free VIPA (virtually imaged phased array) spectrometer described in the previous report. As a reference, the Raman spectra were also acquired for each test. Our current results indicated that POMT defects cause changes in muscle elasticity, which suggests that muscular dystrophy conditions may be also associated with abnormalities in muscle elastic properties.

  16. Experimental observation of stochastic, periodic, and localized light structures in a brillouin cavity system

    Science.gov (United States)

    Ding, Yingchun; Feng, Qi; Zhang, Bin; Liu, Zhongxuan; Tang, Xin; Lin, Chengyou; Chen, Zhaoyang

    2017-06-01

    It has been an important research subject to find new nonlinear optical phenomena. In this paper, we report the experimental observation of stochastic, periodic, and localized light structures in a super long single-mode standard fiber with external optical feedback provided by the fiber end. The end facet reflection provides an analogous Fabry-Perot stimulated Brillouin resonator cavity. By increasing the pump power to exceed stimulated Brillouin scattering threshold, we observed light structures exhibiting extremely rich temporal-pulse characteristics that had never been reported in literature before, including supercontinuum background generation, the localization of periodic optical structure formation, fission, and compression. These optical structures are of period-doubling distribution and have different recurrence rates. What is more interesting is that we have observed sets of low frequency bipolar cycle-pulse trains that is often seen in the electrical field and hardly seen in pure optical system. Real-time specification of dynamical temporal regimes of laser operation may bring new insight into rich underlying nonlinear physics of practical fiber cavity systems. Therefore, some new nonlinear optical phenomena have been observed.

  17. 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)

  18. Brillouin optical correlation domain analysis in composite material beams

    DEFF Research Database (Denmark)

    Stern, Yonatan; London, Yosef; Preter, Eyal

    2017-01-01

    with optical fiber sensors. In this work, we report high-resolution distributed Brillouin sensing over standard fibers that are embedded in composite structures. A phase-coded, Brillouin optical correlation domain analysis (B-OCDA) protocol was employed, with spatial resolution of 2 cm and sensitivity of 1 °K......) estimating the stiffness and Young’s modulus of a composite beam; and (c) distributed strain measurements across the surfaces of a model wing of an unmanned aerial vehicle. The measurements are supported by the predictions of structural analysis calculations. The results illustrate the potential added values...

  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. Small angle neutron scattering study of disordered and crystalline iron nanoparticle assemblies

    International Nuclear Information System (INIS)

    Farrell, D.F.; Ijiri, Y.; Kelly, C.V.; Borchers, J.A.; Rhyne, J.J.; Ding, Y.; Majetich, S.A.

    2006-01-01

    Monodisperse surfactant-coated iron nanoparticles are used to form both disordered nanoparticle assemblies and ordered face-centered cubic nanoparticle crystals. The structural order is probed by small angle X-ray scattering, and the magnetic scattering is studied using small angle neutron scattering. The magnetic scattering corresponding to different length scales is interpreted in terms of collective correlations among the particles within the assemblies

  1. Detection of sinkhole formation via Brillouin Optical-Fiber Time-Domain Reflectrometry (BOTDR)

    Science.gov (United States)

    Linker, R.; Klar, A.

    2009-04-01

    Sinkholes have been considered a major natural hazard in the Dead Sea region since their apparition more than 15 year ago. Although these sinkholes develop slowly over several months, they collapse very suddenly without any warning signs, which makes them especially dangerous to both people and infrastructures. The most commonly accepted mechanism for sinkholes formation in the Dead Sea area is dissolving of salt in subsurface layers. As a result of salt dissolution, the load that was carried originally by the salt layers is transferred to the other soil layers. When this load exceeds the layers' holding capacity, collapse occurs. Throughout this load-transfer process, small mechanical deformations must develop in the soil and the present study investigates the use of Brillouin Optical-Fiber Time-Domain Reflectrometry (BOTDR) for detecting these changes. BOTDR uses the Brillouin-scattering of the light along the optic fiber to estimate the temperature or strain profile in the fiber in a distributed manner. Following temperature compensation, such a system allows for nearly-continuous distributed monitoring of strains over distances of tens of kilometers with a spatial resolution of about 1 meter. In the present study, an analytical solution of the strains that develop in the soil due to sinkhole development was used to simulate the BOTDR signals that would be produced by an optic fiber buried one meter below the soil surface. These simulated "ideal" signals were corrupted artificially to account for the actual spatial resolution of the signal analyzer and random measurement errors. In addition, BOTDR signals due to above-surface disturbances (400kg loading and rain) that were obtained experimentally, were superimposed to the simulated signals. Three thousands BOTDR signals were generated with sinkhole radii and depths ranging from 1.5 to 4.0m and from 10 to 30m, respectively. These signals were subjected to wavelet decomposition and the most informative wavelet

  2. Development of in situ Brillouin spectroscopy at high pressure and high temperature with synchrotron radiation and infrared laser heating system: Application to the Earth's deep interior

    Science.gov (United States)

    Murakami, Motohiko; Asahara, Yuki; Ohishi, Yasuo; Hirao, Naohisa; Hirose, Kei

    2009-05-01

    Seismic wave velocity profiles in the Earth provide one of the strongest constraints on structure, mineralogy and elastic properties of the Earth's deep interior. Accurate sound velocity data of deep Earth materials under relevant high-pressure and high-temperature conditions, therefore, are essential for interpretation of seismic data. Such information can be directly obtained from Brillouin scattering measurement. Here we describe an in situ Brillouin scattering system for measurements at high pressure and high temperature using a laser heated diamond anvil cell and synchrotron radiation for sample characterization. The system has been used with single-crystal and polycrystalline materials, and with glass and fluid phase. It provided high quality sound velocity and elastic data with X-ray diffraction data at high pressure and/or high temperature. Those combined techniques can potentially offer the essential information for resolving many remaining issues in mineral physics.

  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. 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...

  5. A neutron scattering study of liquid helium-4

    International Nuclear Information System (INIS)

    Andersen, K.H.

    1991-11-01

    The results of high-resolution, high-accuracy, high-precision neutron inelastic measurements on liquid 4 He are presented. In the collective excitation region, the temperature-dependence of the sharp one-phonon peak is studied and seen to exhibit a qualitative change at T λ . The Woods-Svensson hypothesis that the scattering separates naturally into parts proportional to the macroscopic normal and superfluid densities is tested and is found to be too simplistic to describe the detailed temperature dependence. A novel theoretical approach by Glyde and Griffin is evaluated. Their formulation establishes the microscopic connection between the Bose condensate and the phonon excitations in superfluid 4 He. The present parameterisation of their model describes the qualitative temperature dependence well. At high momentum transfer we obtain estimates of the momentum distribution above and below T λ , by extracting the Q-dependence of the fourth central moment of the scattering. The obtained n(p) at T>T λ is in very good agreement with theoretical calculations. Our low-temperature momentum distribution is more sharply peaked than at high temperature, but reflects the lack of higher-order terms in the short-time expansion used for extraction of the fourth moment. Estimates of the mean kinetic energy per atom are obtained and are slightly higher than previous experimental estimates, but in agreement with theoretical calculations. From this, we evaluate the magnitude of the condensate fraction, and find n 0 (T = 0) 10.3 ± 1.0%. (author)

  6. 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

  7. A Study of Multiple Scattering in BGO and LYSO Single Crystal Scintillators

    Directory of Open Access Journals (Sweden)

    Kittipong Seingsanoh

    2016-08-01

    Full Text Available The angular distribution of multiple Compton scatterings from BGO and LYSO single crystal scintillators was studied at various scattering angles. Gamma photons with 662 keV energy, acquired from a 137Cs source, were used. The scattered photons were detected by a 51mm × 51mm NaI(Tl scintillation detector. The overall energy correlated to the total number of scattered incidents was analytically reconstructed. The research found that the multiply scattered incidents had the same energy as received from the singly scattered distribution, as the attribution of multiply scattered incidents near the 90° scattering angle revealed. The research results were in agreement with the theoretical calculations.

  8. Quantum-Chemical Calculation and Visualization of the Vibrational Modes of Graphene in Different Points of the Brillouin Zone.

    Science.gov (United States)

    Lebedieva, Tetiana; Gubanov, Victor; Dovbeshko, Galyna; Pidhirnyi, Denys

    2015-12-01

    Different notations of graphene irreducible representations and optical modes could be found in the literature. The goals of this paper are to identify the correspondence between available notations, to calculate the optical modes of graphene in different points of the Brillouin zone, and to compare them with experimental data obtained by Raman and coherent anti-Stokes Raman scattering (CARS) spectroscopy. The mechanism of the resonance enhancement of vibration modes of the molecules adsorbed on graphene in CARS experiments is proposed. The possibility of appearance of the discrete breathing modes is discussed.

  9. Beyond the random phase approximation: Stimulated Brillouin backscatter for finite laser coherence times

    International Nuclear Information System (INIS)

    Korotkevich, Alexander O.; Lushnikov, Pavel M.; Rose, Harvey A.

    2015-01-01

    We developed a linear theory of backward stimulated Brillouin scatter (BSBS) of a spatially and temporally random laser beam relevant for laser fusion. Our analysis reveals a new collective regime of BSBS (CBSBS). Its intensity threshold is controlled by diffraction, once cT c exceeds a laser speckle length, with T c the laser coherence time. The BSBS spatial gain rate is approximately the sum of that due to CBSBS, and a part which is independent of diffraction and varies linearly with T c . The CBSBS spatial gain rate may be reduced significantly by the temporal bandwidth of KrF-based laser systems compared to the bandwidth currently available to temporally smoothed glass-based laser systems

  10. Dynamics of ponderomotive self-focusing and periodic bursts of stimulated Brillouin backscattering in plasmas

    International Nuclear Information System (INIS)

    Andreev, N.E.; Gorbunov, L.M.; Tarakanov, S.V.; Zykov, A.I.

    1993-01-01

    The space--time evolution of ponderomotive self-focusing of electromagnetic beams in a plasma is investigated. The quasineutral, hydrodynamic plasma response to the ponderomotive force is considered. The set of coupled quasioptic and acoustic equations is solved both analytically and numerically for slab and cylindrical beams. It is shown that the transient process of self-focusing has the form of a nonlinear wave propagating along the beam axis from boundary into the interior of a plasma with velocity considerably higher than the ion-sound velocity. Mutual dynamics of self-focusing and stimulated Brillouin backscattering (SBBS) is computed. It is shown that self-focusing results in the high intensity periodical bursts of SBBS. However, the time average level of scattered radiation is quite low

  11. Crossed beam reactive scattering of oxygen atoms and surface scattering studies of gaseous condensation

    International Nuclear Information System (INIS)

    Sibener, S.J.

    1979-09-01

    A high pressure, radio frequency discharge nozzle beam source was developed for the production of very intense (greater than or equal to 10 18 atoms sr -1 sec -1 ) supersonic beams of oxygen atoms. This source is capable of producing seeded beams of ground state O( 3 P/sub J/) atoms when dilute oxygen-argon mixtures are used, with molecular dissociation levels exceeding 80% being realized for operation at pressures up to 350 torr. When dilute oxygen-helium mixtures are employed both ground state O( 3 P/sub J/) and excited state O( 1 D 2 ) atoms are present in the terminal beam, with molecular dissociation levels typically exceeding 60% being achieved for operation at pressures up to 200 torr. Atomic oxygen mean translational energies from 0.14 to 0.50 eV were obtained using the seeded beams technique, with Mach numbers as high as 10 (FWHM Δ v/v approx. = 20%) being realized. The IC1, CF 3 I, C 6 H 6 , and C 6 D 6 reactions are discussed in detail. The IC1 and CF 3 I studies have enabled us to determine an improved value for the bond energy of the IO radical: D/sub o/(IO) = 55 +- 2 kcal/mole. The IO product angular and velocity distributions have been used to generate center-of-mass flux contour maps, which indicate that these two reactions proceed via relatively long-lived collision complexes whose mean lifetimes are slightly shorter than their respective rotational periods. The O( 3 P/sub J/) + C 6 H 6 and C 6 D 6 reactions were studied in order to elucidate the reaction mechanism, and, in particular, to identify the primary reaction products produced in these reactions. Finally, a series of beam-surface scattering experiments are described which examined the internal and translational energy dependence of molecular condensation probabilities for collisions involving either CC1 4 or SF 6 and their respective condensed phases. 117 references

  12. Brillouin Distributed Fiber Sensors: An Overview and Applications

    Directory of Open Access Journals (Sweden)

    C. A. Galindez-Jamioy

    2012-01-01

    Full Text Available A review focused on real world applications of Brillouin distributed fiber sensors is presented in this paper. After a brief overview of the theoretical principles, some works to face the two main technical challenges (large dynamic range and higher spatial resolution are commented. Then an overview of some real and on-field applications is done.

  13. 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

  14. MUNU: study of the neutrino-electron scattering

    International Nuclear Information System (INIS)

    Cerna, C.

    2000-11-01

    MUNU is an experiment dedicated to electron-neutrino scattering studies and in particular to neutrino magnetic moment search at a nuclear power plant in Bugey (France). MUNU is based on a gaseous time projection chamber (TPC) immersed in 8 tons of liquid scintillator acting as an active anti-Compton shielding. A preliminary analysis of the first results of this experiment corresponding to about 24 days of data collecting draws a line on the value of the neutrino magnetic moment: μ ν -bar e ≤ 1.97 10 -10 μ B (68% confidence level). All along this work, it is shown that the combined use of a TPC and of a light detection system is valuable for discriminating particles and for discarding signals from background noise

  15. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Sudirman; Gunawan; Prasetyo, S.M.; Karo Karo, A.; Lahagu, I.M.; Darwinto, Tri [Materials Science Research Center, National Nuclear Energy Agency, Serpong, Tangerang (Indonesia)

    1999-10-01

    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. Neutron scattering study of layered silicates pillared with alkylamnonium ions

    International Nuclear Information System (INIS)

    Neumann, D.A.; Rush, J.J.; Nicol, J.M.; Wada, N.; Fan, Y.; Kim, H.; Solin, S.; Pinnavaia, P.; Trevino, S.F.

    1990-01-01

    Incoherent, inelastic neutron scattering has been used to study the vibrational spectra of tetramethylammonium montmorillonite and trimethylammonium vermiculite in the energy range 20-140 meV. For both systems peaks are observed due to the internal modes of the intercalate and to the excitations of the hydroxyl groups within the host layers. For the montmorillonite sample, it is found that the steric constraints imposed on the tetramethylammonium ion by the bounding clay layers contribute an additional 28 meV to the rational barrier of the methyl groups. This tetramethylammonium ion occupies. For the trimethylammonium vermiculite sample normal mode analysis of the internal modes of the intercalated ion shows that the N-H bond is parallel to the c-axis of the host

  18. 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

  19. Magnetic dynamics of fine particles studied by inelastic neutron scattering

    CERN Document Server

    Hansen, M F; Moerup, S; Lefmann, K; Clausen, K N; Lindgaard, P A

    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 antiferromagnetic alpha-Fe sub 2 O sub 3 nanoparticles.

  20. Scattering studies on cryoglobulins stability and aggregation properties

    Energy Technology Data Exchange (ETDEWEB)

    Bicev, R.N.; Oliveira, E.A.; Oliveira, C.L.P.; Brandao, H. [Universidade de Sao Paulo (USP), SP (Brazil); Andrade, L.E.C. [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil)

    2012-07-01

    Full text: Cryoglobulins are proteins of the immunoglobulin(Ig) type, which play an important role in infections, autoimmune diseases and neoplastic disorders[1]. When in abnormal concentrations in the blood, cryoglobulins can aggregate and precipitate at temperatures below 37 deg C, forming large complexes with dimensions in the range of 40 nm up to 1 {mu}m depending on the temperature, leading to damage of arteries and veins of small caliber. The objective of this study is to investigate the aggregation dynamics of cryoglobulin solutions through scattering techniques as SAXS (small angle X-Ray scattering). For the SAXS measures it was used the protein in aqueous and the system temperature was varied between 38:5 deg C and 4 deg C. The protein concentration was 10mg/mL.The GNOM [2] program was used for the first data analysis. This program performs the Fourier transform (IFT) of the scattering data, which provides the overall particle size, radius of gyration and some indications of the particle shape. The IFT analysis can be used to the so called ab initio modeling which provides a three-dimensional model for particle shape. This model was an attempt to obtain a real space representation for the particle system. Although it was possible to verify difference in the particle diameter for the different temperatures, the models provide a branched structure which can indicate polydispersity of shapes/sizes and also flexible structures. Interestingly, the construction of Kratky Plots, (I {center_dot} q{sup 2} vs q), which provide the compactness degree of a structure, indicated that the particles were highly flexible. Therefore another model procedure, which models the protein as polymer-like structure[3], have to be used. Using the recently developed Ensemble Optimization Method (EOM) [4] it was possible to obtain a very good fit for the experimental dataset, the distributions of radius of gyration and also three-dimensional representations of the possible

  1. High energy x-ray reflectivity and scattering study from spectrum-x-gamma flight mirrors

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Budtz-Jørgensen, Carl; Frederiksen, P. Kk

    1993-01-01

    Line radiation from Fe K-alpha(1), Cu K-alpha(1), and Ag K-alpha(1) is used to study the high energy X-ray reflectivity and scattering behavior of flight-quality X-ray mirrors having various Al substrates. When both the specular and the scattered radiation are integrated, near theoretical...... reflectivities are found for all mirrors. Results of scattering studies show that scattering is strongly correlated with the Al foil type. Mirrors based on new 0.4 mm Al foil are found to have a typical scattering FWHM of about 1.1 arcmin, whereas mirrors based on 0.3 mm Al foil have an FWHM of greater than 1.......5 arcmin. For all mirrors and for all energies, the scattering is found to exhibit the characteristic asymmetries predicted by a first order vector scattering theory....

  2. Experimental determination of the berilium phonon spectra using inelastic neutro scattering

    International Nuclear Information System (INIS)

    Sirota, N.N.; Bulat, I.A.

    1976-01-01

    A study has been made of in elastic scattering of cold neutrons with energies between 0.0022 and 0.00523 eV by polycrystalline beryllium and restoration of its phonon spectrum. The specimen studied is a block of polycrystalline beryllium. In the case of beryllium the averaging of coherent effects upon scattering on a thick specimen takes place as a result of multiple internal Bragg-type reflections of neutrons which undergo inelastic scattering with absorption of phonons. The thickness of the spheric averaging layer for Esub(6) = 0.00523 eV is almost equal to the maximum dimension of the Brillouin band. The phonon spectrum of beryllium for three mean energies used of incident neutrons has been demonstrated. The phonon spectrum of beryllium, measured for the first time, is of interest for quantitative calculations of a number of its physical properties

  3. Neutron and light scattering studies of polymers adsorbed on laponite

    International Nuclear Information System (INIS)

    Nelson, Andrew Robert John

    2002-01-01

    The adsorption of poly(ethylene oxide) (PEO) and various poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (Pluronic) copolymers onto the synthetic clay Laponite, was investigated using Small Angle Neutron Scattering (SANS) and Dynamic Light Scattering (DLS). The Laponite particles are anisotropic, with a relatively high aspect ratio; but are the same order of magnitude in size as the polymer radius of gyration. Consequently, the particles present a radically different adsorption geometry compared to a locally planar interface, that is assumed by the majority of adsorption studies. The PEO homo-polymer formed thin layers, with the layer thickness being much smaller on the face than on the edge of the particle. Furthermore, the face thickness remained constant with increasing molecular weight, unlike the edge thickness, which grew with a small power law dependence on the molecular weight. Although the hydrodynamic thicknesses (DLS) were larger than those observed with SANS, the layer thicknesses were much smaller than that expected for polymer adsorption on spherical particles. Experimentally determined inter-particle structure factors suggested that the adsorbed PEO layers provided a steric repulsion term to the inter-particle interactions. The autocorrelation functions for aggregating Laponite dispersions were followed with DLS. It was found that the stabilisation provided by the adsorbed layer reduced the aggregation rate, with lower molecular weights being most effective. SANS and DLS measurements on Laponite/Pluronic systems revealed that the thickness of the Pluronic layer was the same on the edge and face of the particle. As the Pluronic anchor fraction decreased, and the PEO block molecular weight increased, a growth in the layer size and adsorbed amount was observed. The low anchor fraction Pluronics had higher adsorbed amounts and thicker layers, than the highest M w homo-polymers, demonstrating the importance of the PPO block in the

  4. A Study on Scattered Field of Ultrasonic Wave Using the Boundary Element Method

    International Nuclear Information System (INIS)

    Lee, Joon Hyun; Lee, Seo Il

    2000-01-01

    Ultrasonic technique which is one of the most common and reliable nondestructive evaluation techniques has been applied to evaluate the integrity of structures by analyzing the characteristics of signal scattered from internal defects. Therefore, the numerical analysis of the ultrasonic scattered field is absolutely necessary for the accurate and quantitative estimation of internal defects. Various modeling techniques now play an important role in nondestructive evaluation and have been employed to solve elastic wave scattering problems. Because the elastodynamic boundary element method is useful to analyze the scattered field in infinite media. it has been used to calculate the ultrasonic wavefields scattered from internal defects. In this study, a review of the boundary element method used for elastic wave scattering problems is presented and, as examples of the boundary element method, the scattered fields due to a circular cavity subjected to incident SH-wave and due to a surface-breaking crack subjected to incident Rayleigh wave are illustrated

  5. 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.

  6. 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) is compared with S (κ,ω) determined by a molecular-dynamics calculation and with that calculated from a linearized Vlasov equation. For κ≤0.3 Å-1 the experimental S (κ,ω) is compared with the values predicted by hydrodynamic theory....

  7. A study of scattered radiation effect on digital radiography imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Cheol Ha [Dept. of Radiological Science, Dongseo University, Busan (Korea, Republic of)

    2017-03-15

    Scattered radiation is inherent phenomenon of x-ray, which occurs to the subject (or patient). Therefore it cannot be avoidable but also interacts as serious noise factor because the only meaningful information on x-ray radiography is primary x-ray photons. The purpose of this study was to quantify scattered radiation for various shooting parameters and to verify the effect of anti-scatter grid. We employed beam stopper method to characterize scatter to primary ratio. To evaluate effect on the projection images calculated contrast to noise ratio of given shooting parameters. From the experiments, we identified the scattered radiation increases in thicker patient and smaller air gap. Moreover, scattered radiation degraded contrast to noise ratio of the projection images. We find out that the anti-scatter grid rejected scattered radiation effectively, however there were not fewer than 100% of scatter to primary ratio in some shooting parameters. The results demonstrate that the scattered radiation was serious problem of medical x-ray system, we confirmed that the scattered radiation was not considerable factor of digital radiography.

  8. Neutron scattering in the proximate quantum spin liquid α-RuCl3

    Science.gov (United States)

    Banerjee, Arnab; Yan, Jiaqiang; Knolle, Johannes; Bridges, Craig A.; Stone, Matthew B.; Lumsden, Mark D.; Mandrus, David G.; Tennant, David A.; Moessner, Roderich; Nagler, Stephen E.

    2017-06-01

    The Kitaev quantum spin liquid (KQSL) is an exotic emergent state of matter exhibiting Majorana fermion and gauge flux excitations. The magnetic insulator α-RuCl3 is thought to realize a proximate KQSL. We used neutron scattering on single crystals of α-RuCl3 to reconstruct dynamical correlations in energy-momentum space. We discovered highly unusual signals, including a column of scattering over a large energy interval around the Brillouin zone center, which is very stable with temperature. This finding is consistent with scattering from the Majorana excitations of a KQSL. Other, more delicate experimental features can be transparently associated with perturbations to an ideal model. Our results encourage further study of this prototypical material and may open a window into investigating emergent magnetic Majorana fermions in correlated materials.

  9. 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 ...

  10. 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 ...

  11. 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)

  12. 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)

  13. 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.

  14. 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)

  15. 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

  16. Scattered radiation in DBT geometries with flexible breast compression paddles: a Monte Carlo simulation study

    Science.gov (United States)

    Díaz, Oliver; García, Eloy; Oliver, Arnau; Martí, Joan; Martí, Robert

    2017-03-01

    Scattered radiation is an undesired signal largely present in most digital breast tomosynthesis (DBT) projection images as no physically rejection methods, i.e. anti-scatter grids, are regularly employed, in contrast to full- field digital mammography. This scatter signal might reduce the visibility of small objects in the image, and potentially affect the detection of small breast lesions. Thus accurate scatter models are needed to minimise the scattered radiation signal via post-processing algorithms. All prior work on scattered radiation estimation has assumed a rigid breast compression paddle (RP) and reported large contribution of scatter signal from RP in the detector. However, in this work, flexible paddles (FPs) tilting from 0° to 10° will be studied using Monte Carlo simulations to analyse if the scatter distribution differs from RP geometries. After reproducing the Hologic Selenia Dimensions geometry (narrow angle) with two (homogeneous and heterogeneous) compressed breast phantoms, results illustrate that the scatter distribution recorded at the detector varies up to 22% between RP and FP geometries (depending on the location), mainly due to the decrease in thickness of the breast observed for FP. However, the relative contribution from the paddle itself (3-12% of the total scatter) remains approximately unchanged for both setups and their magnitude depends on the distance to the breast edge.

  17. Small-angle neutron scattering study of natural aquatic nanocolloids.

    Science.gov (United States)

    Jarvie, Helen P; King, Stephen M

    2007-04-15

    We examine the potential of small-angle neutron scattering (SANS) as a quantitative tool for studying nanostructure and length scales in natural freshwater aquatic colloidal dispersions (river water, river bed sediments, agricultural field drainage and slurry). Our results show that natural aquatic colloids are generally fractal with 3D network-type structures. None of these structures are consistent with diffusion-limited (DLCA) or reaction-limited (RLCA) particleparticle aggregation processes. The results also suggest three characteristic length scales: one ca. 3-10 nm, which we identify with "primary particle" sizes, another of ca. 20-50 nm suggestive of small aggregates, and the last ca. 50-200 nm which we postulate arises from transient networks of the aggregates. The role of organic matter in mediating colloid structure in aquatic dispersions was examined by neutron contrast variation and by measuring samples both before and after treatment with hydrogen peroxide. The results suggest that the aggregate network structure is mediated by organic matter.

  18. Neutron-scattering studies of Yb-bearing silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, A.J.G.; Loong, C.K.; Wagner, J.

    1993-09-01

    The static and dynamic magnetic response of the Yb{sup 3+} ions in 2Na{sub 2}O{center_dot}Yb{sub 2}O{sub 3}{center_dot}6SiO{sub 2} glass and the isochemical crystalline silicate Na{sub 3}YbSi{sub 3}O{sub 9} has been studied by neutron diffraction, inelastic magnetic-scattering, and magnetic susceptibility measurements. The rare earth sites in the glass have an average coordination number of 5.6 {plus_minus} 0.5 and give a mean rare earth-oxygen bond length of 2.23 {Angstrom}; average Si-O and O-O coordination numbers and bond distances are comparable to those in vitreous SiO{sub 2}. The magnetic excitation spectrum of the Na{sub 3}YbSi{sub 3}O{sub 9} material was analyzed by a crystal-field model using a method of descending symmetry. The magnetic susceptibility and the excitation spectrum of the Yb glasses can be described by a distribution of ligand-field effects on the Yb{sup 3+} ions that are similar to the nominal crystal field in crystalline Na{sub 3}YbSi{sub 3}O{sub 9}.

  19. 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)

  20. Neutron Scattering Studies of Pure and Chromium - Vanadium Sesquioxide

    Science.gov (United States)

    Yethiraj, Mohana

    1985-12-01

    The metal insulator transitions in pure and chromium -doped vanadium sesquioxide (V(,2)O(,3)) were investigated using elastic and inelastic neutron scattering techniques. These samples undergo a number of transitions as a function of temperature and doping. At the highest temperature, all specimens are in a metallic (M') phase. As the temperature is lowered, samples with less than 0.5% Cr transform to a second metallic (M) state. For those samples with Cr content between 0.5% and 1.8%, the system transforms to an insulating (I') phase prior to the transition to the M phase. For samples with >1.8% Cr, the M phase is entirely bypassed. At temperatures below (TURN)160K, all samples transform to an antiferromagnetic insulating (AFI) phase. The transition to the AFI state is accompanied by a structural distortion as well. The aim of this study was to add to our understanding of the driving mechanism(s) effecting the various metal-insulator transformations and in particular, the low temperature magnetic transition.

  1. 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)

  2. 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

  3. BRILLOUIN INSTABILITY IN FIBER LASERS DOPED BY POWER ...

    African Journals Online (AJOL)

    afin de décrire l'évolution temporelle du milieu amplificateur. On ne tient pas compte des ordres supérieurs des composantes Stokes. Le gain de la diffusion Brillouin n'est plus considéré comme instantané [1]. Les ondes sont décrites en termes d'amplitudes des champs optiques et acoustique et des conditions aux limites.

  4. 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

  5. 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

  6. Positron Scattering from Molecules: An Experimental Cross Section Compilation for Positron Transport Studies and Benchmarking Theory

    Science.gov (United States)

    Brunger, M. J.; Buckman, S. J.; Ratnavelu, K.

    2017-06-01

    We present a compilation of recommended positron-molecule cross sections for a range of scattering processes including elastic scattering, vibrational excitation, discrete electronic-state excitation, positronium formation, ionization, and also for the grand total cross section. Where possible, in particular for possible application in positron transport simulations for a given molecule, we try and list data for energies in the range 0.1-1000 eV although in practice the actual energy is highly target-molecule and scattering process specific. Aside from being relevant to positron transport studies, through, for example, Monte Carlo simulations, the present compilation should also be germane for benchmarking the validity and accuracy of positron-molecule scattering calculations and, just as importantly, to allow a comparison with corresponding electron scattering results. That latter comparison can shed real light on the projectile-target interactions that underpin the scattering dynamics.

  7. [Terahertz-band study on surface enhanced Raman scattering of nanoparticle].

    Science.gov (United States)

    Wu, Yu-Deng; Ren, Guang-Jun; Hao, Yun; Yao, Jian-Quan

    2013-05-01

    Study on surface-enhanced Raman scattering in the terahertz-band proved in that the terahertz-band Raman enhancement also exists. By studing principles of electromagnetic enhancement of surface-enhanced Raman scattering, using the finite difference time-domain method, the electromagnetic enhancement of surface enhanced Raman scattering of nano-particles irradiated by terahertz-wave was simulated, and the enhancement effect of terahertz waves was analyzed. Simulation experiments show that using finite-difference time-domain method could obtain effectively accurate simulation result of nano-particle scattering, proving that for terahertz waves, surface-enhanced effects on the surface of the nano-particle also exist. The results for surface enhanced Raman scattering extended from the visible and infrared to terahertz-band, and provide a basis for application of the combination of surface-enhanced Raman scattering and terahertz-wave.

  8. 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

  9. 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

  10. Charge and orbital ordered states studied by using x-ray anomalous scattering terms

    CERN Document Server

    Nakao, H

    2002-01-01

    Recently, the studies utilizing anomalous scattering term of atomic scattering factor near absorption edge, so called x-ray anomalous scattering and resonant x-ray scattering, have been rapidly developed. This technique has especially contributed to the determination of the charge-orbital ordered structure in strongly correlated electron system. In this paper, we present the typical examples - the charge ordering of V sup 4 sup + and V sup 5 sup + in NaV sub 2 O sub 5 and the antiferro-quadrupole ordering (orbital ordering) of Ge sup 3 sup + ions in CeB sub 6 (author)

  11. 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

  12. 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...

  13. Small angle neutron scattering study on the aggregation behaviour ...

    Indian Academy of Sciences (India)

    Small angle neutron scattering (SANS) measurements on aqueous solutions of four polyethylene oxide–polypropylene oxide–polyethylene oxide block copolymers (commercially known as Pluronic®)F88, P85, F127 and P123 in the presence of hydrophobic C14Diol (also known as Surfynol® 104) reveal information on ...

  14. 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 ...

  15. 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 ...

  16. 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 ...

  17. 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....

  18. 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...

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

    Indian Academy of Sciences (India)

    Small-angle neutron scattering; biological macromolecules; protein solution. PACS Nos 61.12.Ex; 87.14.Ee; 87.15.Nn. Biological macromolecules such as proteins possess a specific shape and charge, which regulate and ... Figure 1a shows the phase diagram of crystallization of 1 wt% lysozyme protein solution as a ...

  20. 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.

  1. Observation of soft phonon mode in TbFe3(BO3)4 by inelastic neutron scattering

    Science.gov (United States)

    Pavlovskiy, M. S.; Shaykhutdinov, K. A.; Wu, L. S.; Ehlers, G.; Temerov, V. L.; Gudim, I. A.; Shinkorenko, A. S.; Podlesnyak, A.

    2018-02-01

    The phonon dispersion in terbium iron borate TbFe3(BO3)4 has been measured by inelastic neutron scattering in a temperature range 180 studied by ab initio calculations. Significant, but not complete, softening of the transverse acoustic (TA) branch has been observed at the corner of the Brillouin zone (Λ point) at temperatures T ⪆TS , in full agreement with theoretical calculations. The TA soft mode undergoes considerable broadening at the Λ point near the transition temperature that can be attributed to the anharmonic interference between transverse acoustic and optical modes.

  2. Optical scattering noise in high Q fiber ring resonators and its effect on optoelectronic oscillator phase noise.

    Science.gov (United States)

    Saleh, Khaldoun; Merrer, Pierre-Henri; Llopis, Olivier; Cibiel, Gilles

    2012-02-15

    Nonlinear phenomena occurring in an optical fiber ring resonator featuring ultrahigh Q factor are experimentally studied. The laser is locked onto the resonator, and the optical power induced in the resonator is controlled. The onset of the first stimulated Brillouin scattering wave occurs at an optical input power as low as -9 dBm in these resonators. When the resonator is used as the frequency reference device in an optoelectronic oscillator (OEO), it has been found that these parasitic signals mix with the OEO signal and degrade its phase noise. More than 20 dB improvement of the OEO phase noise has been demonstrated by limiting these nonlinear optical effects.

  3. Optimizing signal collection efficiency of the VIPA-based Brillouin spectrometer

    Directory of Open Access Journals (Sweden)

    Zhaokai Meng

    2015-07-01

    Full Text Available Brillouin spectroscopy is an emerging tool for microscopic optical imaging as it allows for noninvasive and direct assessment of the viscoelastic properties of materials. Recent advances of background-free confocal Brillouin spectrometer allows investigators to acquire the Brillouin spectra for turbid samples as well as transparent ones. However, due to strong signal loss induced by the imperfect optical setup, the Brillouin photons are usually immersed in background noise. In this report, we proposed and experimentally demonstrated multiple approaches to enhance the signal collection efficiency. A signal enhancement by > 4 times can be observed, enabling observation of ultra-weak signals.

  4. Two-color Brillouin ring laser gyro with gyro-compassing capability.

    Science.gov (United States)

    Raab, M; Quast, T

    1994-09-15

    We investigated the gyro-compassing capability of a Brillouin ring laser gyro set up in a two-color operation. Two counterpropagating pump lasers initiated two Brillouin ring lasers on different resonances of a fiber-optic ring resonator cavity, which excluded the mutual intracavity interaction between both counterpropagating Brillouin lasers. Additionally minimizing the external feedback channels of the individual Brillouin lasers allowed for high-resolution measurements, e.g., the horizontal component of the Earth's rotation rate (10.0 degrees /h at Uberlingen, Germany, which corresponded to a beat frequency of 6.85 Hz).

  5. Scattering tensors and optical transitions in Si and Ge

    CSIR Research Space (South Africa)

    Kunert, HW

    2012-08-01

    Full Text Available and L high symmetry points and the highest maximum of the valence band (VB) in the Brillouin zone of Oh7 space group symmetry are determined. The elements of El-Ph scattering tensors are linear combinations of the Clebsch-Gordon coefficients (CGC...

  6. 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...

  7. Neutron scattering study of the excitation spectrum of solid helium at ...

    Indian Academy of Sciences (India)

    Neutron scattering study of the excitation spectrum of solid helium at ultra-low temperatures. Elizabeth Blackburn John Goodkind ... We have carried out a series of elastic and inelastic neutron scattering measurements on single crystals of hcp 4He at temperatures down to 60 mK. While we have found no direct evidence of ...

  8. Comparison between electron and neutron Compton scattering studies

    Directory of Open Access Journals (Sweden)

    Moreh Raymond

    2015-01-01

    Full Text Available We compare two techniques: Electron Compton Scattering (ECS and neutron Compton scattering (NCS and show that using certain incident energies, both can measure the atomic kinetic energy of atoms in molecules and solids. The information obtained is related to the Doppler broadening of nuclear levels and is very useful for deducing the widths of excited levels in many nuclei in self absorption measurements. A comparison between the atomic kinetic energies measured by the two methods on the same samples is made. Some results are also compared with calculated atomic kinetic energies obtained using the harmonic approximation where the vibrational frequencies were taken from IR/Raman optical measurements. The advantages of the ECS method are emphasized.

  9. Magnetic nanostructures studied by polarized small angle neutron scattering

    International Nuclear Information System (INIS)

    Wiedenmann, Albrecht; Kammel, Martin; Heinemann, Andre

    2005-01-01

    Small Angle Neutron Scattering using polarised neutrons is introduced as a contrast variation technique for magnetic systems. The potential of this technique is illustrated on diluted Ferrofluids. Composition, magnetization and size distributions of magnetic core-shell composite particles and magnetic aggregates could be precisely evaluated beside non-magnetic micelles and free surfactants of similar sizes. Structure factors have been extracted which revealed a local pseudo-crystalline ordering of the magnetic particles induced by magnetic fields

  10. 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)

  11. 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

  12. 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

  13. 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)

  14. Nonlinear behavior of stimulated scatter in large underdense plasmas

    International Nuclear Information System (INIS)

    Kruer, W.L.; Estabrook, K.G.

    1979-01-01

    Several nonlinear effects which limit Brillouin and Raman scatter of intense light in large underdense plasmas are examined. After briefly considering ion trapping and harmonic generation, we focus on the self-consistent ion heating which occurs as an integral part of the Brillouin scattering process. In the long-term nonlinear state, the ion wave amplitude is determined by damping on the heated ion tail which self-consistently forms. A simple model of the scatter is presented and compared with particle simulations. A similar model is also applied to Raman scatter and compared with simulations. Our calculations emphasize that modest tails on the electron distribution function can significantly limit instabilities involving electron plasma waves

  15. Transmission properties in a photonic crystal with a Dirac-like point located at the Brillouin zone center

    Science.gov (United States)

    Gao, H.; Zhou, Y.; Zhao, L.; Wei, G.

    2017-11-01

    Light transmission properties of a two-dimensional dielectric photonic crystal (PC) with a Dirac-like point located at the Brillouin zone center are studied. The results show that at the Dirac-like point, the transmittance remains constant rather than inversely varying with the PC's thickness, that is, this transmission does not follow the pseudo-diffusive phenomenon. Moreover, since the PC with a Dirac point at the Brillouin zone center can mimic zero index material (ZIM), transmittance of a real homogeneous ZIM layer is also theoretically investigated. Invariant transmittance is obtained again and the constant transmittance at the Dirac-like point is confirmed. Physical mechanisms of the pseudo-diffusive transmission as well as the constant transmission are both analyzed. It is found that the Dirac point is a critical state between band gaps and transmission bands, where the wave vector takes a complex number. It is the imaginary part of the wave vector which causes the decrease of the transmittance. While at the Dirac-like point at the center of the Brillouin zone, an additional flat band makes the Dirac point frequency fall into a transmission band where the wave vector is a real number, therefore the transmittance does not display any decrease tendency.

  16. High-resolution, on-chip RF photonic signal processor using Brillouin gain shaping and RF interference.

    Science.gov (United States)

    Choudhary, Amol; Liu, Yang; Morrison, Blair; Vu, Khu; Choi, Duk-Yong; Ma, Pan; Madden, Stephen; Marpaung, David; Eggleton, Benjamin J

    2017-07-19

    Integrated microwave photonics has strongly emerged as a next-generation technology to address limitations of conventional RF electronics for wireless communications. High-resolution RF signal processing still remains a challenge due to limitations in technology that offer sub-GHz spectral resolution, in particular at high carrier frequencies. In this paper, we present an on-chip high-resolution RF signal processor, capable of providing high-suppression spectral filtering, large phase shifts and ns-scale time delays. This was achieved through tailoring of the Brillouin gain profiles using Stokes and anti-Stokes resonances combined with RF interferometry on a low-loss photonic chip with strong opto-acoustic interactions. Using an optical power of <40 mW, reconfigurable filters with a bandwidth of ~20 MHz and an extinction ratio in excess of 30 dB are synthesized. Through the concept of vector addition of RF signals we demonstrate, almost an order of magnitude amplification in the phase and delay compared to devices purely based upon the slow-light effect of Brillouin scattering. This concept allows for versatile and power-efficient manipulation of the amplitude and phase of RF signals on a photonic chip for applications in wireless communications including software defined radios and beam forming.

  17. The effect of signal to noise ratio on accuracy of temperature measurements for Brillouin lidar in water

    Science.gov (United States)

    Liang, Kun; Niu, Qunjie; Wu, Xiangkui; Xu, Jiaqi; Peng, Li; Zhou, Bo

    2017-09-01

    A lidar system with Fabry-Pérot etalon and an intensified charge coupled device can be used to obtain the scattering spectrum of the ocean and retrieve oceanic temperature profiles. However, the spectrum would be polluted by noise and result in a measurement error. To analyze the effect of signal to noise ratio (SNR) on the accuracy of measurements for Brillouin lidar in water, the theory model and characteristics of SNR are researched. The noise spectrums with different SNR are repetitiously measured based on simulation and experiment. The results show that accuracy is related to SNR, and considering the balance of time consumption and quality, the average of five measurements is adapted for real remote sensing under the pulse laser conditions of wavelength 532 nm, pulse energy 650 mJ, repetition rate 10 Hz, pulse width 8 ns and linewidth 0.003 cm-1 (90 MHz). Measuring with the Brillouin linewidth has a better accuracy at a lower temperature (15 °C), based on the classical retrieval model we adopt. The experimental results show that the temperature error is 0.71 °C and 0.06 °C based on shift and linewidth respectively when the image SNR is at the range of 3.2 dB-3.9 dB.

  18. Single-frequency pulsed Brillouin-thulium fiber laser at 2 µm with nonlinear polarization rotation and active phase modulation

    Science.gov (United States)

    Wang, Xiong; Lv, Haibin; Zhou, Pu; Wu, Weijun; Wang, Xiaolin; Xiao, Hu; Liu, Zejin

    2014-10-01

    We present a single-frequency (SF) pulsed fiber laser at 2 µm based on stimulated Brillouin scattering in a thulium-doped fiber laser. The effective feedback of the fiber laser is quite weak to induce pulse operation. Nonlinear polarization rotation and active phase modulation are employed to compress the pulse width and stabilize the pulse train. This SF pulsed Brillouin-thulium fiber laser (BTFL) can generate a stable pulse train with a repetition rate of ˜310 kHz and a pulse width of ˜200 ns. The repetition rate of the pulse train can be adjusted by controlling the cavity length, and the pulse width can be tuned between 200 and 500 ns. The central wavelength locates at 1971.58 nm with an optical signal-to-noise ratio of more than 40 dB, and the linewidth is about 6 MHz. This is the first demonstration of the SF pulsed BTFL as far as we know.

  19. Neutron scattering studies of magnetic molecular spin clusters

    International Nuclear Information System (INIS)

    Chaboussant, G.; Basler, R.; Sieber, A.; Ochsenbein, S.T.; Guedel, H.-U.

    2004-01-01

    Molecular magnets are crystalline materials made up of interacting magnetic centres within each molecule. Each such 'spin-cluster' is magnetically well isolated from its neighbours due to the surrounding ligands. The resulting magnetic properties are governed by exchange interactions between neighbouring spins and magneto-crystalline anisotropy. We present a brief overview of the salient features observed in three very different molecular magnets (Mn 4 , Ni 12 and V 15 ) where magnetic frustration plays a crucial role. It is demonstrated that Inelastic Neutron Scattering (INS) is an excellent technique to elucidate complex behaviour associated with geometrically frustrated molecular magnets

  20. In-situ studies with photons, neutrons and electrons scattering

    International Nuclear Information System (INIS)

    Kannengiesser, Thomas; Babu, Sudarsanam Suresh; Komizo, Yu-ichi; Ramirez, Antonio J.

    2010-01-01

    In-situ scattering and diffraction measurements using synchrotron and neutron beam lines have become a viable tool to look at the non-equilibrium processing of advanced materials. This volume presents the subject from the theoretical and experimental standpoint, in order to provide a closer insight into the different synchrotron and neutron diffraction techniques as well as innovative microscopy techniques. It addresses the following items: - phase detection and quantification - In-situ welding experiments - Stress/strain build-up - model development and Simulation - Analysis tools and programming (orig.)

  1. 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.

  2. Electron back scattered diffraction study of SmCo magnets

    Energy Technology Data Exchange (ETDEWEB)

    Yonamine, T. [Divisao de Metrologia de Materiais-INMETRO, Av. Nossa Senhora das Gracas, 50 (Xerem), 25250-020 Duque de Caxias, RJ (Brazil)], E-mail: tyfukuhara@inmetro.gov.br; Fukuhara, M.; Machado, R. [Divisao de Metrologia de Materiais-INMETRO, Av. Nossa Senhora das Gracas, 50 (Xerem), 25250-020 Duque de Caxias, RJ (Brazil); Missell, F.P. [Divisao de Metrologia de Materiais-INMETRO, Av. Nossa Senhora das Gracas, 50 (Xerem), 25250-020 Duque de Caxias, RJ (Brazil); Departamento de Fisica e Quimica, Centro de Ciencias Exatas e Tecnologia, Universidade de Caxias do Sul, 95070-560 Caxias do Sul, RS (Brazil)

    2008-07-15

    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){sub z} magnets are also discussed.

  3. Optimization of the Brillouin operator on the KNL architecture

    Science.gov (United States)

    Dürr, Stephan

    2018-03-01

    Experiences with optimizing the matrix-times-vector application of the Brillouin operator on the Intel KNL processor are reported. Without adjustments to the memory layout, performance figures of 360 Gflop/s in single and 270 Gflop/s in double precision are observed. This is with Nc = 3 colors, Nv = 12 right-hand-sides, Nthr = 256 threads, on lattices of size 323 × 64, using exclusively OMP pragmas. Interestingly, the same routine performs quite well on Intel Core i7 architectures, too. Some observations on the much harderWilson fermion matrix-times-vector optimization problem are added.

  4. Rayleigh-Brillouin spectrum in special relativistic hydrodynamics

    International Nuclear Information System (INIS)

    Garcia-Perciante, A. L.; Garcia-Colin, L. S.; Sandoval-Villalbazo, A.

    2009-01-01

    In this paper we calculate the Rayleigh-Brillouin spectrum for a relativistic simple fluid according to three different versions available for a relativistic approach to nonequilibrium thermodynamics. An outcome of these calculations is that Eckart's version predicts that such spectrum does not exist. This provides an argument to question its validity. The remaining two results, which differ one from another, do provide a finite form for such spectrum. This raises the rather intriguing question as to which of the two theories is a better candidate to be taken as a possible version of relativistic nonequilibrium thermodynamics. The answer will clearly require deeper examination of this problem.

  5. Room scatter effects in Total Skin Electron Irradiation: Monte Carlo simulation study.

    Science.gov (United States)

    Nevelsky, Alexander; Borzov, Egor; Daniel, Shahar; Bar-Deroma, Raquel

    2017-01-01

    Total Skin Electron Irradiation (TSEI) is a complex technique which usually involves the use of large electron fields and the dual-field approach. In this situation, many electrons scattered from the treatment room floor are produced. However, no investigations of the effect of scattered electrons in TSEI treatments have been reported. The purpose of this work was to study the contribution of floor scattered electrons to skin dose during TSEI treatment using Monte Carlo (MC) simulations. All MC simulations were performed with the EGSnrc code. Influence of beam energy, dual-field angle, and floor material on the contribution of floor scatter was investigated. Spectrum of the scattered electrons was calculated. Measurements of dose profile were performed in order to verify MC calculations. Floor scatter dependency on the floor material was observed (at 20 cm from the floor, scatter contribution was about 21%, 18%, 15%, and 12% for iron, concrete, PVC, and water, respectively). Although total dose profiles exhibited slight variation as functions of beam energy and dual-field angle, no dependence of the floor scatter contribution on the beam energy or dual-field angle was found. The spectrum of the scattered electrons was almost uniform between a few hundred KeV to 4 MeV, and then decreased linearly to 6 MeV. For the TSEI technique, dose contribution due to the electrons scattered from the room floor may be clinically significant and should be taken into account during design and commissioning phases. MC calculations can be used for this task. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  6. On the use of Cu:Be clamp cells in magnetization and neutron scattering studies

    International Nuclear Information System (INIS)

    Pfleiderer, C; Huxley, A D; Hayden, S M

    2005-01-01

    The use of miniature clamp cells made of Cu:Be for magnetization and neutron scattering studies in the medium pressure range is reviewed by giving recent results achieved in studies of UGe 2 , MnSi and ZrZn 2 . The experiments reviewed here establish in particular that small samples can be studied rather well at high pressures using a variety of different techniques, notably conventional diffraction, cold and thermal neutron triple axes and small-angle neutron scattering

  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. 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.

  9. Elastic neutron scattering study of proton dynamics in glycerol

    Science.gov (United States)

    Cornicchi, Elena; Cinelli, Stefania; Natali, Francesca; Onori, Giuseppe; Paciaroni, Alessandro

    2004-07-01

    A recent neutron scattering investigation on lysozyme embedded in glycerol-water mixtures has shown that solvent dynamics is crucial in determining the dynamical properties of the biomolecule itself (Biophys. J. 83 (2002) 1157). To better understand the role played by solvent, we have performed an elastic incoherent neutron scattering (INS) experiment as a function of the temperature on pure glycerol. To directly compare the dynamics of the solvated protein and that of the pure solvent, we settled the same experimental conditions and applied the same data analysis procedure as in Paciaroni et al. (Biophys. J. 83 (2002) 1157). By using a double-well model and taking into account for the global molecular diffusion, we exploited the measured intensity to estimate the mean square displacements (MSD) of glycerol hydrogen atoms. We found that the total MSD deviate from the low-temperature vibrational harmonic trend at approximately T=235K, consistent with the value of the critical temperature reported in literature (Phys. Rev. E 55 (1997) 3183). The present investigation suggests that the internal dynamics of glycerol molecules, i.e. the vibrations and reorientations of hydrogen atoms relative to the molecular centre of mass (c.o.m.), can be put in relationship with the protein dynamics.

  10. Elastic neutron scattering study of proton dynamics in glycerol

    International Nuclear Information System (INIS)

    Cornicchi, Elena; Cinelli, Stefania; Natali, Francesca; Onori, Giuseppe; Paciaroni, Alessandro

    2004-01-01

    A recent neutron scattering investigation on lysozyme embedded in glycerol-water mixtures has shown that solvent dynamics is crucial in determining the dynamical properties of the biomolecule itself (Biophys. J. 83 (2002) 1157). To better understand the role played by solvent, we have performed an elastic incoherent neutron scattering (INS) experiment as a function of the temperature on pure glycerol. To directly compare the dynamics of the solvated protein and that of the pure solvent, we settled the same experimental conditions and applied the same data analysis procedure as in Paciaroni et al. (Biophys. J. 83 (2002) 1157). By using a double-well model and taking into account for the global molecular diffusion, we exploited the measured intensity to estimate the mean square displacements (MSD) of glycerol hydrogen atoms. We found that the total MSD deviate from the low-temperature vibrational harmonic trend at approximately T=235 K, consistent with the value of the critical temperature reported in literature (Phys. Rev. E 55 (1997) 3183). The present investigation suggests that the internal dynamics of glycerol molecules, i.e. the vibrations and reorientations of hydrogen atoms relative to the molecular centre of mass (c.o.m.), can be put in relationship with the protein dynamics

  11. 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

  12. Small-angle neutron scattering and inelastic neutron scattering studies on β-cyclodextrins and hydroxypropyl-β-cyclodextrins

    International Nuclear Information System (INIS)

    Maccarrone, S.; Magazu, S.; Migliardo, F.; Mondio, F. Mondio

    2004-01-01

    This work reports new experimental neutron scattering results on β-cyclodextrins and hydroxypropyl-β-cyclodextrins. The small angle neutron scattering analysis shows that the typical conformation of the investigated systems in crystalline state is also maintained in aqueous solution. Inelastic neutron scattering results emphasize the more 'crystalline' character of β-cyclodextrins in comparison with hydroxypropyl β-cyclodextrins from the differences in the vibrational spectra of these compounds

  13. 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

  14. 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)

  15. 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

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

    International Nuclear Information System (INIS)

    Niimura, Nobuo

    1994-01-01

    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

  17. Local structure and lattice dynamics study of low dimensional materials using atomic pair distribution function and high energy resolution inelastic x-ray scattering

    Science.gov (United States)

    Shi, Chenyang

    Structure and dynamics lie at the heart of the materials science. A detailed knowledge of both subjects would be foundational in understanding the materials' properties and predicting their potential applications. However, the task becomes increasingly dicult as the particle size is reduced to the nanometer scale. For nanostructured materials their laboratory x-ray scattering patterns are overlapped and broadened, making structure determination impossible. Atomic pair distribution function technique based on either synchrotron x-ray or neutron scattering data is known as the tool of choice for probing local structures. However, to solve the "structure problem" in low-dimensional materials with PDF is still challenging. For example for 2D materials of interest in this thesis the crystallographic modeling approach often yields unphysical thermal factors along stacking direction where new chemical intuitions about their actual structures and new modeling methodology/program are needed. Beyond this, lattice dynamical investigations on nanosized particles are extremely dicult. Laboratory tools such as Raman and infra-red only probe phonons at Brillouin zone center. Although in literature there are a great number of theoretical studies of their vibrational properties based on either empirical force elds or density functional theory, various approximations made in theories make the theoretical predictions less reliable. Also, there lacks the direct experiment result to validate the theory against. In this thesis, we studied the structure and dynamics of a wide variety of technologically relevant low-dimensional materials through synchrotron based x-ray PDF and high energy resolution inelastic x-ray scattering (HERIX) techniques. By collecting PDF data and employing advanced modeling program such as DiPy-CMI, we successfully determined the atomic structures of (i) emerging Ti3C2, Nb4C3 MXenes (transition metal carbides and/or nitrides) that are promising for energy storage

  18. 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

  19. A simple student laboratory practice for the study of light scattering by cylindrical bodies

    Science.gov (United States)

    Mabiala Masiala, Toto; Phuku Phuati, Edmond; Kazadi Mukenga, B. Albert

    2017-08-01

    The study of light scattering by cylindrical bodies is of great importance in many aspects, but most of the time; it is studied in a very theoretical manner. In that work, we present a simple manner to study scattering of light by cylindrical bodies. The method combines the use of a simple experimental set-up using a He-Ne laser as a source, a circular paper screen, and the use of a simple code for simulation using the Lorentz-Mie formalism. In that way, the student can compare the experimental results with the simulation. They can qualitatively notice the difference of the behavior of scattering by a low-loss dielectric cylinder, a metallic cylinder, and an absorbing cylinder. Simulation can help students to follow the evolution of the scattering regime when the relative diameter of the cylinder, with respect to the incident wavelength, changes. A focus is stressed especially when the radius becomes far below the wavelength.

  20. Radiation damage study using small-angle neutron scattering

    Science.gov (United States)

    Rétfalvi, E.; Török, Gy; Rosta, L.

    2000-03-01

    Nuclear radiation provides important changes in the microstructure of metallic components of nuclear power plant and research reactors, influencing their mechanical properties. The investigation of this problem has primary interest for the safety and life-time of such nuclear installations. For the characterization of this kind of nanostructures small angle neutron scattering technique is a very useful tool. We have carried out experiments on samples of irradiated reactor vessel material and welded components of VVER-440-type reactors on the SANS instrument at the Budapest Research Reactor. In our measurements irradiated as well as non-irradiated samples were compared and magnetic field was applied for viewing the magnetic structure effects of the materials. A clear modification of the structure due to irradiation was obtained. Our data were analyzed by the ITP92 code, the inverse Fourier transform program of O. Glatter [1].

  1. Lattice dynamics of aluminium studied by neutron inelastic scattering

    International Nuclear Information System (INIS)

    Salles Filho, J.B.V.

    1982-01-01

    Measurements of phonon dispersion relations of aluminum along the high symmetry directions were performed by coherent inelastic scattering of thermal neutrons technique. All measurements were taken at room temperature using the IPEN triple axis neutron spectrometer. The results obtained with accuracy are in good agreement with the published data. The dispersion relations were calculated theoretically within the framework of Born-von Karman and Axially Symmetric models, including interactions up to the fifth nearest shell of atoms. The elastic constants were determined using the values of sound propagating velocity obtained directly from the dispersion relations along of high symmetry directions of the crystal. Applying theoretical models the force constants of aluminum were also determined. From these data several physical properties of the metal can be obtained. (Author) [pt

  2. Field study of nanoparticles by small angle neutron scattering

    International Nuclear Information System (INIS)

    Mirebeau, I.; Hennion, M.; Bellouard, C.

    1994-01-01

    In nanometric iron particles, magnetic correlations are determined by small angle neutron scattering and compared to their values calculated in a simple superparamagnetic model. The introduction of a Lorentzian shape for the magnetic form factor is necessary to obtain a good fit of the data. This reveals two extra features: a spin disorder at the surface of the particles which persists in applied field, and a distribution in the particle sizes not probed by X-rays. The field alignment becomes easier with decreasing temperature. This is no longer true for samples with bigger and closer-packed particles, where strong dipolar interactions develop at low temperatures and oppose to the external field. 4 figs., 3 refs

  3. 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)

  4. Brillouin-zone database on the Bilbao Crystallographic Server.

    Science.gov (United States)

    Aroyo, Mois I; Orobengoa, Danel; de la Flor, Gemma; Tasci, Emre S; Perez-Mato, J Manuel; Wondratschek, Hans

    2014-03-01

    The Brillouin-zone database of the Bilbao Crystallographic Server (http://www.cryst.ehu.es) offers k-vector tables and figures which form the background of a classification of the irreducible representations of all 230 space groups. The symmetry properties of the wavevectors are described by the so-called reciprocal-space groups and this classification scheme is compared with the classification of Cracknell et al. [Kronecker Product Tables, Vol. 1, General Introduction and Tables of Irreducible Representations of Space Groups (1979). New York: IFI/Plenum]. The compilation provides a solution to the problems of uniqueness and completeness of space-group representations by specifying the independent parameter ranges of general and special k vectors. Guides to the k-vector tables and figures explain the content and arrangement of the data. Recent improvements and modifications of the Brillouin-zone database, including new tables and figures for the trigonal, hexagonal and monoclinic space groups, are discussed in detail and illustrated by several examples.

  5. Internal dynamics in SDS micelles: neutron scattering study.

    Science.gov (United States)

    Sharma, V K; Mitra, S; Verma, G; Hassan, P A; Garcia Sakai, V; Mukhopadhyay, R

    2010-12-30

    The molecular dynamics of sodium dodecyl sulfate (SDS) micelle has been investigated using high-resolution incoherent quasielastic neutron scattering technique. Data analysis clearly shows presence of two distinct motions: whole micellar motion or global diffusion and faster internal motion of the SDS monomer. The global diffusion associated with the whole micelle is found to be Fickian in nature, and the corresponding diffusion coefficients are found to be consistent with those obtained from dynamic light scattering measurements. The internal motion is described with a model consistent with the structure of the micelle and which accounts for the flexibility of the chains. The SDS monomer consists of a head group, which lies on the surface of the globular micelle, and a tail that hangs from the head toward the center of the globule. Considering various factors like conformational changes of the SDS chains, bending, stretching of the chemical bonds, etc., the dynamics of the SDS molecules is successfully described by a model in which the hydrogen atoms undergo localized translational motion confined within spherical volumes. This volume increases linearly along the SDS chain such that the hydrogen atoms closer to the head group move within smaller spheres with lower diffusion constant than the hydrogen atoms away from the head group. This model is found to be consistent with the data over the whole temperature and concentration range. Diffusivity and the volume of the spheres are also found to increase with temperature. The effect of lowering the SDS concentration is found to be similar to that of increasing the temperature.

  6. An undergraduate laboratory study of the polarisation of annihilation photons using Compton scattering

    OpenAIRE

    Knights, Patrick; Ryburn, Finlay; Tungate, Garry; Nikolopoulos, Konstantinos

    2018-01-01

    An experiment for the advanced undergraduate laboratory which allows students to study the effect of photon polarisation in Compton scattering and to explore q\\ uantum entanglement is described. The quantum entangled photons are produced through electron-positron annihilation in the $S$-state, and their polarisations a\\ re analysed using the Compton scattering cross-section dependence on the photon polarisation. The equipment necessary for this experiment is available at a typ\\ ical undergrad...

  7. Direct ion heating in overdense plasmas through the Brillouin instability driven by relativistic whistler waves

    Science.gov (United States)

    Sano, Takayoshi; Hata, Masayasu; Iwata, Natsumi; Mima, Kunioki; Sentoku, Yasuhiko

    2017-10-01

    Strong magnetic fields over kilo-Tesla have been available in the laboratory by the use of ultra-intense lasers. It would be interesting to apply those strong fields to other laser experiments such as the inertial confinement fusion and laboratory astrophysics. The characteristics of laser-plasma interactions could be modified significantly by the presence of such strong magnetic fields. We investigate electromagnetic wave propagation in overdense plasmas along the magnetic field for a right-hand circularly polarized wave by PIC simulations. Since the whistler mode has no cutoff density, it can penetrate into overdense plasmas and interact directly with charged particles there. When the external field strength is near a critical value defined by that the cyclotron frequency is equal to the laser one, it is reported that electrons are accelerated efficiently by the cyclotron resonance. However, if the field strength is far beyond the critical value, the cyclotron resonance is inefficient, while the ions gain a large amount of energy directly from the laser light owning to the Brillouin scattering. As the result, only ions are heated up selectively. We will discuss about the application of this ion heating in dense plasmas. This work was supported by JSPS KAKENHI Grant Number JP15K21767.

  8. The aggregation behavior of zinc-free insulin studied by small-angle neutron scattering

    DEFF Research Database (Denmark)

    Pedersen, J.S.; Hansen, S.; Bauer, R.

    1994-01-01

    The aggregation behavior of zinc-free insulin has been studied by small-angle neutron scattering as a function of pH and ionic strength of the solution. The pair distance distribution functions for the 12 samples have been obtained by indirect Fourier transformation. The results show......-particle correlation effects, were obtained by an indirect Fourier transformation, omitting the data at small scattering vectors, which are influenced by these effects. By this procedure the weight-averaged molecular mass and the average radius of gyration were determined. These parameters vary from 1.3 times...... to an equilibrium model recently introduced by Kadima et al. (1993). The neutron scattering results agree well with the predictions of this model except that broader mass distributions are suggested by neutron scattering....

  9. Reactive and nonreactive scattering of N-2 from Ru(0001): A six-dimensional adiabatic study

    DEFF Research Database (Denmark)

    Diaz, C.; Vincent, J.K.; Krishnamohan, G.P.

    2006-01-01

    We have studied the dissociative chemisorption and scattering of N-2 on and from Ru(0001), using a six-dimensional quasiclassical trajectory method. The potential energy surface, which depends on all the molecular degrees of freedom, has been built applying a modified Shepard interpolation method...... probabilities are found to be very small even for translational energies much higher than the minimum reaction barrier, in good agreement with experiment. A comparison to previous low dimensional calculations shows the importance of taking into account the multidimensional effects of N-2 rotation...... results show a strong dependence of reaction on the initial vibrational state. Computed angular scattering distributions and parallel translation energy distributions are in good agreement with experiments on scattering, but the theory overestimates vibrational and rotational excitations in scattering. (c...

  10. Inelastic neutron scattering from glass formers

    International Nuclear Information System (INIS)

    Buchenau, U.

    1997-01-01

    Neutron spectra below and above the glass transition temperature show a pronounced difference between strong and fragile glass formers in Angell's fragility scheme. The strong anharmonic increase of the inelastic scattering with increasing temperature in fragile substances is absent in the strongest glass former SiO 2 . That difference is reflected in the temperature dependence of Brillouin sound velocities above the glass transition. Coherent inelastic neutron scattering data indicate a mixture of sound waves and local modes at the low frequency boson peak. A relation between the fragility and the temperature dependence of the transverse hypersound velocity at the glass temperature is derived. (author)

  11. Problems involved in quantitative gamma camera scintigraphy. F. Scattered radiation correction techniques for multi-isotope studies

    International Nuclear Information System (INIS)

    Soussaline, F.; Todd-Pokropek, A.E.

    1976-01-01

    The resolution correction uses the camera response (FDP) as a function of photon energy and origin (primary or scattered). From filters thus calculated may be generated the scattered photon contribution which must then be substracted from the lower energy image. The linear combination method uses an operator which allows the spatial distribution of the scattering factor to be accounted for. In default of using an analytical knowledge of the scattering spectrum a preliminary study on a phantom is necessary [fr

  12. 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)

  13. Polarized neutron reflectivity and scattering studies of magnetic heterostructures

    Science.gov (United States)

    Zabel, H.; Theis-Bröhl, K.

    2003-02-01

    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.

  14. Neutron scattering studies of low dimensional magnetic systems

    DEFF Research Database (Denmark)

    Hansen, Ursula Bengård

    CoCl2 · 2D2O have been investigated with neutron scattering experiments.CoCl2 · 2D2O can be considered a quasi one dimensional Ising system. This means, thatit is a near ideal model material for investigating low dimensional magnetic phenomena.The excitation spectrum of CoCl2 · 2D2O has been...... investigated at low temperaturesand in a longitudinal magnetic eld using neutron spectroscopy. Here we observe thehybridisation of the magnon bound states, inherent to the low dimensional nature ofCoCl2 · 2D2O.At higher temperature, signatures which can be attributed to Magnetic Bloch Oscillationsis observed......The results of this thesis can be divided into two parts, one concerning neutron scatteringstudies of low dimensional magnetic systems and one concerning neutron optics for theEuropean Spallation Source (ESS).In the part concerning low dimensional magnetic systems, three aspects of the dynamicsof...

  15. 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

  16. 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)

  17. Selective optical scattering characterisation of tissue malignancy using Mueller matrix polarimetry: a simulation study

    Science.gov (United States)

    Fathima, Adeeba; Sujatha, N.

    2016-04-01

    Quantitative Mueller polarimetry optically characterizes a medium and is reflected upon by the ultrastructural changes in it. Tissue morphology changes occur during advent of diseases like cancer neoplasia. This alters the Mueller matrix characterizing the tissue as an optical element. The nucleus size undergoes an approximate doubling during the development of cancer. Cell crowding during cancer increases the number density of the nuclei per unit volume. Modeling the cell nuclei as main scattering centers, a systematic computational study on how Mueller matrix elements vary for an increase in scatterer size and number density is performed. Simulation on polarized light transport of wavelength 633nm through a slab of size 3 mm comprising of spherical scatterers in a medium of refractive index 1.33 is carried out. Light propagation is modeled using Monte Carlo method and meridian plane method is adopted for tracking the polarization state change. The stokes vector of the outgoing light is tracked to calculate the Mueller matrix images of the light backscattered from the slab. The Mueller matrix elements as well as depolarization factors are derived. The depolarization index increases with scatterer size. Along with nucleus size, change in the cell number density is also expected in the different stages of the cancer growth. Volume fraction of the scatterers in medium is varied as an indicator of this number density change. Behavior of Mueller matrix with respect to change in scattering coefficient due to variation in scatterer size and volume fraction is studied. It is observed that the depolarization index derived from Mueller matrix has selective discrimination towards the change in scattering coefficient caused due to size change and volume fraction change respectively.

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

    Energy Technology Data Exchange (ETDEWEB)

    Deloar, Hossain M [Department of Investigative Radiology, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565 (Japan); Watabe, Hiroshi [Department of Investigative Radiology, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565 (Japan); Aoi, Toshiyuki [Department of Investigative Radiology, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565 (Japan); Iida, Hidehiro [Department of Investigative Radiology, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565 (Japan)

    2003-04-21

    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 {sup 201}Tl, {sup 99m}Tc, {sup 123}I and {sup 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 {sup 131}I, {sup 123}I and {sup 99m}Tc, respectively. For a 2 mm aperture, these values were 65% for {sup 131}I, 16% for {sup 123}I and 12% for {sup 99m}Tc. For all pinholes, {sup 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 {sup 201}Tl, {sup 99m}Tc, {sup 123}I and {sup 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 {sup 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 {sup 201}Tl.

  19. 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.

  20. Anomalous inelastic neutron scattering from calcite

    International Nuclear Information System (INIS)

    Dove, M.T.; Harris, M.J.; Winkler, B.; Hagen, M.E.; Keele Univ.; Powell, B.M.; Steigenberger, U.

    1992-01-01

    Inelastic neutron scattering measurements on calcite (CaCO 3 ) in its low temperature phase have revealed the existence of an unusual column of inelastic scattering at the wavevector corresponding to the F point of the high temperature Brillouin zone. At the same wavevector there is also a transverse acoustic soft mode and the column of scattering ranges in energy from zero up to the soft mode. The intensity of the anomalous scattering increases rapidly with temperature, and is consistent with an Arrhenius relation of the form exp(-T * /T), where T * = 1035 K. We speculate that this scattering arises from thermal fluctuations of the calcite structure into a different ordered structure, which is related to an ordering instability at the F point. Evidence for this possibility has also been obtained from lattice energy calculations. (author)

  1. Diffuse Neutron Scattering of the High Temperature Phase of Fe3O4

    OpenAIRE

    Siratori , K.; Ishii , Y.; Morii , Y.; Funahashi , S.; Yanase , A.

    1997-01-01

    Diffuse neutron scattering is observed for the high temperature phase of magnetite, Fe3O4, in an extended range in the (001) and (011) plane of the Brillouin zone. Contours of scattered intensity shows a characteristic pattern, discs in the (100) plane around the Γ points, spheres around the X points, etc. The intensity of this diffuse scattering increases with decreasing temperature down to the Verwey point and is attributed to the lattice distortion induced by charge fluctuation in the B si...

  2. 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.)

  3. A study on the scattered-rays from the radiation shielding materials

    International Nuclear Information System (INIS)

    Kim, C.K.; Huh, J.

    1980-01-01

    To shield the radiation, we can make use of various materials, but the scattered rays can be caused by the shielding materials. The degree of the scattered rays production is influenced by the nature of the shielding materials and the energy of the radiation, therefore to choose the proper shielding material is the most important matter in radiation protection. Authors made an experimental study on the scattered rays generated from the shielding materials, and obtained the results as follows: In the ranking of the scattered rays production: Cement bricks, black colored fire bricks, and red colored fire bricks were marked the first, the second, and the third ranking respectly, and the last order was lead plates. In the relative ranking of the scattered rays production by energy increase: Lead plates were marked the first order, the next and third order were red colored fire bricks and black colored fire bricks respectively, and cement bricks were marked the last order. The scattered ray ratio of lateral-back point per lateral point were generally decreased by energy increment. The diminishing orders were that lead plates were the first order, and the next and the third order were red colored fire bricks and black colored fire bricks respectively, cement bricks were marked the last order (Author)

  4. Anomalous thermal expansion, negative linear compressibility, and high-pressure phase transition in ZnAu2(CN) 4 : Neutron inelastic scattering and lattice dynamics studies

    Science.gov (United States)

    Gupta, Mayanak K.; Singh, Baltej; Mittal, Ranjan; Zbiri, Mohamed; Cairns, Andrew B.; Goodwin, Andrew L.; Schober, Helmut; Chaplot, Samrath L.

    2017-12-01

    We present temperature-dependent inelastic-neutron-scattering measurements, accompanied by ab initio calculations of the phonon spectra and elastic properties as a function of pressure to quantitatively explain an unusual combination of negative thermal expansion and negative linear compressibility behavior of ZnAu2(CN) 4 . The mechanism of the negative thermal expansion is identified in terms of specific anharmonic phonon modes that involve bending of the -Zn-NC-Au-CN-Zn- linkage. The soft phonon at the L point at the Brillouin zone boundary quantitatively relates to the high-pressure phase transition at about 2 GPa. The ambient pressure structure is also found to be close to an elastic instability that leads to a weakly first-order transition.

  5. Quantum Rabi model in the Brillouin zone with ultracold atoms

    Science.gov (United States)

    Felicetti, Simone; Rico, Enrique; Sabin, Carlos; Ockenfels, Till; Koch, Johannes; Leder, Martin; Grossert, Christopher; Weitz, Martin; Solano, Enrique

    2017-01-01

    The quantum Rabi model describes the interaction between a two-level quantum system and a single bosonic mode. We propose a method to perform a quantum simulation of the quantum Rabi model, introducing an implementation of the two-level system provided by the occupation of Bloch bands in the first Brillouin zone by ultracold atoms in tailored optical lattices. The effective qubit interacts with a quantum harmonic oscillator implemented in an optical dipole trap. Our realistic proposal allows one to experimentally investigate the quantum Rabi model for extreme parameter regimes, which are not achievable with natural light-matter interactions. When the simulated wave function exceeds the validity region of the simulation, we identify a generalized version of the quantum Rabi model in a periodic phase space.

  6. Time gated phase-correlation distributed Brillouin fibre sensor

    Science.gov (United States)

    Denisov, Andrey; Soto, Marcelo A.; Thévenaz, Luc

    2013-05-01

    A random access distributed Brillouin fibre sensor is presented, based on phase modulation using a pseudo-random bit sequence (PRBS) together with time gating. The standard phase-correlation technique is known to show a noise level increasing linearly with the number of measured points due to weak gratings generated randomly along the whole sensing fibre. Here we show how intensity modulated pump and time gated detection significantly improve the signal-tonoise ratio (SNR) of the system with no impact on the spatial resolution. A measurement with 1.1 cm spatial resolution over 3.3 km is demonstrated, representing 300'000 equivalent points. The limitations of the proposed technique are discussed through the paper.

  7. Neutron scattering studies of Cd1−xMnxTe

    DEFF Research Database (Denmark)

    Giebultowicz, T.; Lebech, Bente; Buras, B

    1984-01-01

    The diluted magnetic (‘‘semimagnetic’’) semiconductor Cd1–xMnxTe reveals intriguing spin glass properties. In this paper, the results of neutron scattering studies of Cd1–xMnxTe are presented. The low‐temperature spin correlations have been studied for several single crystal samples in the compos......The diluted magnetic (‘‘semimagnetic’’) semiconductor Cd1–xMnxTe reveals intriguing spin glass properties. In this paper, the results of neutron scattering studies of Cd1–xMnxTe are presented. The low‐temperature spin correlations have been studied for several single crystal samples...

  8. Software development for studies of diffuse scattering using CCD-detectors and synchrotron radiation sources

    CERN Document Server

    Paulmann, C; Bismayer, U

    2001-01-01

    A graphical-user-interface based software system was developed to cover advanced data processing requirements which arise from studies of diffuse scattering in disordered minerals using synchrotron radiation sources and CCD-detectors. The software includes interfaces to standard applications, procedures for numerical processing of large data sets, corrections for sample external scattering and detector-specific distortions, different scaling options to correct the data set against the varying primary beam intensity as well as procedures to reconstruct arbitrary slices in reciprocal space on a regular grid. The software system was successfully applied in studies of diffuse scattering in disordered REE-doped germanates, phase-transition studies of synthetic titanite and studies of the thermal recrystallization behaviour of radiation-damaged (metamict) minerals.

  9. Inelastic neutron scattering studies of methyl chloride synthesis over alumina.

    Science.gov (United States)

    Lennon, David; Parker, Stewart F

    2014-04-15

    Not only is alumina the most widely used catalyst support material in the world, it is also an important catalyst in its own right. One major chemical process that uses alumina in this respect is the industrial production of methyl chloride. This is a large scale process (650,000 metric tons in 2010 in the United States), and a key feedstock in the production of silicones that are widely used as household sealants. In this Account, we show how, in partnership with conventional spectroscopic and reaction testing methods, inelastic neutron scattering (INS) spectroscopy can provide additional insight into the active sites present on the catalyst, as well as the intermediates present on the catalyst surface. INS spectroscopy is a form of vibrational spectroscopy, where the spectral features are dominated by modes involving hydrogen. Because of this, most materials including alumina are largely transparent to neutrons. Advantageously, in this technique, the entire "mid-infrared", 0-4000 cm(-1), range is accessible; there is no cut-off at ~1400 cm(-1) as in infrared spectroscopy. It is also straightforward to distinguish fundamental modes from overtones and combinations. A key parameter in the catalyst's activity is the surface acidity. In infrared spectroscopy of adsorbed pyridine, the shifts in the ring stretching modes are dependent on the strength of the acid site. However, there is a very limited spectral range available. We discuss how we can observe the low energy ring deformation modes of adsorbed pyridine by INS spectroscopy. These modes can undergo shifts that are as large as those seen with infrared inspectroscopy, potentially enabling finer discrimination between acid sites. Surface hydroxyls play a key role in alumina catalysis, but in infrared spectroscopy, the presence of electrical anharmonicity complicates the interpretation of the O-H stretch region. In addition, the deformations lie below the infrared cut-off. Both of these limitations are irrelevant

  10. 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

  11. 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

  12. Silver nanoparticles on nanopatterned LiF(110) surface studied by extreme ultraviolet light scattering

    Energy Technology Data Exchange (ETDEWEB)

    Giglia, Angelo, E-mail: giglia@iom.cnr.it; Nannarone, Stefano [Istituto Officina dei Materiali - Consiglio Nazionale delle Ricerche, Laboratorio Tecnologie Avanzate e NanoSCienza, Area Science Park Basovizza, S.S. 14 Km 163.5, 34149 Trieste (Italy); Miotti, Paolo [Istituto di Fotonica e Nanotecnologie - Consiglio Nazionale delle Ricerche, Via Trasea 7, 35131 Padova (Italy); Parisse, Pietro [Sincrotrone Trieste S.C.p.A., S.S. 14 km 163.5, 34149 Basovizza, Trieste (Italy)

    2015-12-21

    A LiF(110) surface featuring a ridge-and-valley nanopatterned structure periodic along the [−1,1,0] direction (period and height of the order of 30 nm and 10 nm, respectively) formed by [001] macrosteps exposing (100) and (010) facets was functionalized by rows of Ag nanoparticles and studied by elastic light scattering in the energy range 50–100 eV. Families of diffraction efficiencies curves were taken at grazing incidence angle and fixed photon energy as a function of scattering angle, and elastic scattering curves were taken at fixed scattering angle as a function of energy. The scattering curves presented well-defined features ascribable to the periodicities of the surface, or equivalently to the reciprocal q{sub X} vectors correlated with the power spectral density features of topological images of atomic force microscopy. Other characteristics of the functionalized surface, including the height of ridge-valley profile, the Ag nanoparticle dimensions, and the material distribution in the scattering plane, were obtained by fitting the experimental zero and first order efficiency curves to simulation results of a parameterized model. The simulations were carried out adapting an in-house code based on the electromagnetic differential method, and the different material properties were taken into account by a space dependent complex dielectric constant. Information along the direction perpendicular to the scattering plane was not accessible but morphological insights were obtained combining light diffraction with atomic force microscopy. The results indicate nanoparticles with a quasi-ellipsoidal shape prolate along the ridge direction with minor and major axes of ∼12 nm and ∼21 nm, respectively.

  13. 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)

  14. 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)

  15. Bi-Directional Brillouin Optical Time Domain Analyzer System for Long Range Distributed Sensing.

    Science.gov (United States)

    Guo, Nan; Wang, Liang; Wang, Jie; Jin, Chao; Tam, Hwa-Yaw; Zhang, A Ping; Lu, Chao

    2016-12-16

    We propose and experimentally demonstrate a novel scheme of bi-directional Brillouin time domain analyzer (BD-BOTDA) to extend the sensing range. By deploying two pump-probe pairs at two different wavelengths, the Brillouin frequency shift (BFS) distribution over each half of the whole fiber can be obtained with the simultaneous detection of Brillouin signals in both channels. Compared to the conventional unidirectional BOTDA system of the same sensing range, the proposed BD-BOTDA scheme enables distributed sensing with a performance level comparable to the conventional one with half of the sensing range and a spatial resolution of 2 m, while maintaining the Brillouin signal-to-noise ratio (SNR) and the BFS uncertainty. Based on this technique, we have achieved distributed temperature sensing with a measurement range of 81.9 km fiber at a spatial resolution of 2 m and BFS uncertainty of ~0.44 MHz without introducing any complicated components or schemes.

  16. Simulation of simultaneously obtaining ocean temperature and salinity using dual-wavelength Brillouin lidar

    International Nuclear Information System (INIS)

    Yu, Yin; Ma, Yong; Li, Hao; Huang, Jun; Fang, Yu; Liang, Kun; Zhou, Bo

    2014-01-01

    A method for simultaneously obtaining the ocean temperature and salinity based on dual-wavelength Brillouin lidar is proposed in this letter. On the basis of the relationships between the temperature and salinity and the Brillouin shifts, a retrieval model for retrieving the temperature and salinity is established. By using the retrieval model, the ocean temperature and salinity can be simultaneously obtained through the Brillouin shifts. Simulation based on dual-wavelength Brillouin lidar is also carried out for verification of the accuracy of the retrieval model. Results show that the errors of the retrieval model for temperature and salinity are ±0.27 °C and ±0.33‰. (letter)

  17. 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

  18. 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)

  19. Small angle neutron scattering study of the initial stage of lysozyme crystallization process

    International Nuclear Information System (INIS)

    Minezaki, Yoshiaki; Tanaka, Ichiro; Niimura, Nobuo; Ataka, Mituo; Katsura, Tatsuo.

    1993-01-01

    Despite the enormous amount of information obtained from atomic resolution crystal data, the difficulties encountered in growing crystals preclude structural X-ray studies for the majority of known isolated proteins. The protein crystal growth process can be studied by electron microscopy and by light scattering, and recently Ataka and Asai have discussed the kinetics on lysozyme crystal growth. We have conducted small angle neutron scattering (SANS) experiments on the time evolution from the initial stages to the visible size of crystallization of hen egg-white lysozyme. SANS from several kinds of solutions have been carried out. The SANS result showed the distinctive change of time evolution. We have also conducted the experiments under various unsaturated conditions using SANS. From these experiments, we found that even under unsaturated conditions, aggregation of lysozyme was found to be started, against the result of light-scattering experiments. (author)

  20. Neutron scattering studies of BiFeO(3) multiferroics: a review for microscopists.

    Science.gov (United States)

    Sosnowska, I M

    2009-11-01

    Application of the neutron scattering technique in the study of crystal and magnetic properties of multiferroic BiFeO(3) is presented. The crucial role of the neutron scattering technique, complementary to X-ray diffraction method and transmission electron microscopy, is shown. Especially the ultra high-resolution time-of-flight (TOF) neutron diffraction technique used by Sosnowska et al. to detect the magnetic cycloid ordering and its role in studies of physical properties of BiFeO(3) and its alloys are reviewed. The first inelastic neutron scattering patterns of magnetic excitations in BiFeO(3) are also presented. Applications of different microscopy techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), field emission TEM and SEM (FESEM and FETEM), magnetic force microscope (MFM) and polarization force microscopy (PFM) bring insight on the fundamental problem of ferroelectricity and confirm the potential of BiFeO(3) multiferroic material for nanoscale devices.

  1. 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......+-sites. Evidence for short range order is found in the diffuse elastic scattering in the α-phase and the implications for the ionic conductivity are discussed.......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...

  2. 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.

  3. 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

  4. Critical scattering

    Energy Technology Data Exchange (ETDEWEB)

    Stirling, W.G. [Liverpool Univ., Dep. of Physics, Liverpool (United Kingdom); Perry, S.C. [Keele Univ. (United Kingdom). Dept. of Physics

    1996-12-31

    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{sub 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.

  5. 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.)

  6. Studies on ionization and excitation processes in Ps–Li scattering

    Indian Academy of Sciences (India)

    [1], but very little attention [2–8] is given to study such a process. Three differ- ent types of ionization in ... In recent years some attention is given to the studies involving. Ps [12,13] and Ps–atom scattering ..... [20] S Geltman, Topics in atomic collision theory (Academic Press, New York and London,. 1969) p. 142. [21] J A ...

  7. Small-Angle Neutron Scattering study of the NIST mAb reference material

    Science.gov (United States)

    Castellanos, Maria Monica; Liu, Yun; Krueger, Susan; Curtis, Joseph

    Monoclonal antibodies (mAbs) are of great interest to the biopharmaceutical industry because they can be engineered to target specific antigens. Due to their importance, the biomanufacturing initiative at NIST is developing an IgG1 mAb reference material `NIST mAb', which can be used by industry, academia, and regulatory authorities. As part of this collaborative effort, we aim at characterizing the reference material using neutron scattering techniques. We have studied the small-angle scattering profile of the NIST mAb in a histidine buffer at 0 and 150 mM NaCl. Using Monte Carlo simulations, we generate an ensemble of structures and calculate their theoretical scattering profile, which can be directly compared with experimental data. Moreover, we analyze the structure factor to understand the effect of solution conditions on the protein-protein interactions. Finally, we have measured the solution scattering of the NIST mAb, while simultaneously performing freeze/thaw cycles, in order to investigate if the solution structure was affected upon freezing. The results from neutron scattering not only support the development of the reference material, but also provide insights on its stability and guide efforts for its development under different formulations.

  8. 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.

  9. Wentzel-Kramers-Brillouin solution of cut-off frequency for horizontal shear (SH) waves in various inhomogeneous thin films

    Science.gov (United States)

    Cao, Xiaoshan; Shi, Junping; Jin, Feng

    2013-01-01

    The Wentzel-Kramers-Brillouin method is employed to study the cut-off frequencies of the horizontal shear waves in a freestanding functionally graded piezoelectric-piezomagnetic material film with the electrically and magnetically open boundary conditions. An analytical solution, which could be used in analyzing the problems of various functionally graded materials, is proven to have high precision by analytical analysis and a numerical example. The results reveal that the set of cut-off frequencies is a series of approximate arithmetic progressions. A theoretical foundation based on the relationship between the cut-off frequencies and the materials' gradient property is established for nondestructive evaluation.

  10. 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.

  11. 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.

  12. Small-angle neutron-scattering studies on oriented single-crystal superalloys

    Science.gov (United States)

    Gilles, R.; Mukherji, D.; Strunz, P.; Wiedenmann, A.; Wahi, R. P.

    A single-crystal nickel-base superalloy SC16, recently developed for blade applications in land-based gas turbines, was investigated using the SANS instrument (V4) at the BERII reactor in HMI Berlin. The two-dimensional scattering patterns were measured as a function of the crystallographic orientation and analysed by comparing with iso-intensity profiles simulated on the base of a microstructural model of the SC16. Sizes, interparticle distances, volume fraction and morphology of precipitates were determined. Depending on the heat treatment conditions different scattering patterns were observed corresponding to different morphologies of γ‧ precipitates. Additionally some samples showed streaks in the two-dimensional scattering patterns, indicating the presence of precipitates other than γ‧. This was also confirmed by TEM, SEM and X-ray diffraction studies.

  13. The dynamics of hydrogen in metals studied by inelastic neutron scattering

    International Nuclear Information System (INIS)

    Anderson, Ian

    1994-01-01

    The study of H vibrations in metals provides valuable information on metal-hydrogen and hydrogen-hydrogen interactions essential for the understanding of many physical properties ranging from lattice expansion to electronic effects. Most information on H vibrations comes from inelastic neutron scattering (INS). Furthermore due to the large incoherent scattering cross section of H, INS turns out to be an extremely sensitive probe for H site occupation in high dilution conditions where, for instance, neutron diffraction would be insensitive. The results described give a general overview of the valuable information that can be obtained on the interactions of H in metals from inelastic neutron scattering experiments. 38 refs., 18 figs., 3 tabs

  14. Neutron Compton scattering as a molecular characterization technique: A study on NaHF2

    International Nuclear Information System (INIS)

    Colognesi, D.; Pietropaolo, A.; Senesi, R.; Ramirez-Cuesta, A. J.

    2007-01-01

    Inelastic neutron scattering experiments were performed at intermediate and high momentum transfers, up to 85-90 A ring -1 , to study the proton momentum distribution in polycrystalline sodium hydrogen fluoride (NaHF 2 ) at low temperature (below 5 K). The H mean kinetic energy was extracted and compared to the results from hydrogen-projected density of phonon states derived from intermediate momentum transfer inelastic neutron scattering and lattice dynamics simulations. A reasonable agreement between the two figures was found. In addition, relevant aspects of high momentum transfer neutron scattering from NaHF 2 were explored in detail, ranging from an alternative evaluation of final state effects to the role played by the instrumental resolution and to the possibility to reconstruct the potential felt by a proton from its momentum distribution

  15. 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.

  16. Poly(NIPAM) micro gel particle de-swelling: a light scattering and small-angle neutron scattering study

    International Nuclear Information System (INIS)

    Daly, E.; Saunders, B.

    1999-01-01

    Full text: Small-angle neutron scattering (SANS) has been used to investigate structural changes during the de-swelling of poly(N-isopropylacrylamide) [poly(NIPAM)] micro gel particles induced by temperature variation and the addition of free polymer [poly(ethylene oxide)]. The extent of particle de-swelling was characterized by photon correlation spectroscopy (PCS). Thermally-induced de-swelling of poly(NIPAM) / deuterated water dispersions occurred on increasing the temperature in the region of the lower critical solution temperature (LCST). The latter was found to be 34 deg C, which is 2 deg C higher than the value reported for poly(NIPAM) particles dispersed in water. The SANS data exhibit a Porod form (Q -4 ) of scattering in regard to the size of the colloidal particles. However, in the swollen state, the scattering measured at temperatures less than the LCST, also has a contribution from poly(NIPAM) chains in a solution-like environment (Ornstein-Zernicke scattering). The SANS data confirm earlier PCS measurements showing that addition of free polymer induces particle de-swelling. The SANS data obtained using added free polymer are the first examples of their type to be reported

  17. 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).

  18. A light-scattering study of the nonlinear dynamics of electrorheological fluids in oscillatory shear

    International Nuclear Information System (INIS)

    Martin, J.E.; Odinek, J.

    1995-01-01

    We report a real time, two-dimensional light-scattering study of the nonlinear dynamics of field-induced structures in an electrorheological (ER) fluid subjected to oscillatory shear. We have developed a simple kinetic chain model of the observed dynamics by considering the response of a fragmenting/aggregating particle chain to the prevailing hydrodynamic and electrostatic forces. This theory of the dynamics is then used to describe the nonlinear rheology of ER fluids, and it is concluded that light scattering allows one to indirectly probe the stress in an ER fluid. copyright 1995 Society of Rheology

  19. 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

  20. Lattice vibrations in copper at elevated temperatures studied by neutron scattering

    International Nuclear Information System (INIS)

    Larose, A.; Brockhouse, B.N.

    1976-01-01

    The technique of inelastic scattering of thermal neutrons was used to study the temperature dependence of lattice vibrations in Cu in the range 23 deg C to 1063 deg C, i.e. up to 20 deg C below the melting point, and in the various symmetry directions accessible in a (001) scattering plane. Resolution effects were taken into account in the determination of intrinsic phonon frequencies and linewidths. The results indicate a general softening of the lattice as the temperature is raised, the vibrations of transverse polarization being more strongly affected than those of longitudinal polarization. (author)

  1. Structures and interactions among globular proteins above the isoelectric point in the presence of divalent ions: A small angle neutron scattering and dynamic light scattering study

    Science.gov (United States)

    Kundu, Sarathi; Pandit, Subhankar; Abbas, Sohrab; Aswal, V. K.; Kohlbrecher, J.

    2018-02-01

    Small angle neutron scattering study reveals that at pD ≈ 7.0, above the isoelectric point of the globular protein Bovine Serum Albumin (BSA), in the presence of different divalent ions (Mg2+, Ca2+, Sr2+ and Ba2+), the short-range attractive interaction remains nearly constant and the intermediate-range repulsive interaction decreases with increasing salt concentration up to a certain concentration value but after that remains unchanged. However, for the monovalent ion (Na+), repulsive interaction decreases gradually up to 1 M salt concentration. Dynamic light scattering study shows that for all ions, diffusion coefficient of BSA decreases with increasing salt concentration and then nearly saturates.

  2. Collective Excitations in Liquid Hydrogen Observed by Coherent Neutron Scattering

    DEFF Research Database (Denmark)

    da Costa Carneiro, Kim; Nielsen, M.; McTague, J. P.

    1973-01-01

    Coherent scattering of neutrons by liquid parahydrogen shows the existence of well-defined collective excitations in this liquid. Qualitative similarity with the scattering from liquid helium is found. Furthermore, in the range of observed wave vectors, 0.7 Å-1 ≤κ≤3.1 Å-1, extending from the firs...... through the third Brillouin zones in the solid, S(κ,ω) is remarkably similar to the scattering law expected from a polycrystal. For κ≤2.3 Å-1 the observed spectra satisfy the one-phonon sum rule with mean square displacement 〈u2〉=1.0 Å2....

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

    Indian Academy of Sciences (India)

    [6]. The studies carried out on individual hydrotropes or surfactant-hydrotrope mixtures support the fact that hydrotropes are capable of forming self-aggregates in the aqueous solutions above a certain minimum concentration known as mini- mum hydrotrope concentration (MHC), analogous to critical micellar concentration.

  5. Small angle neutron scattering study of temperature-independent ...

    Indian Academy of Sciences (India)

    headgroup due to an increase in counterion dissociation decreases the size of ionic micelles, it is the decreased hydration of the headgroup that increases the size of nonionic micelles with an increase in temperature. Herein, we report SANS studies on a formulation of mixed micelles of ionic and nonionic surfactants that.

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

    Indian Academy of Sciences (India)

    2014-02-15

    Feb 15, 2014 ... Abstract. In-situ monitoring of silver nanoparticle formation was studied in thin films of poly- vinyl alcohol and silver nitrate. We proposed the observation of surface-enhanced Raman spec- troscopy (SERS) as a novel and simple technique to record the growth of silver nanoparticles in polyvinyl alcohol thin ...

  7. Invitation to neutron scattering study at ultra high pressure

    International Nuclear Information System (INIS)

    Hamaya, Nozomu

    2006-01-01

    Understanding of the pressure evolution of physical and chemical properties of hydrogen is the ultimate goal of the high pressure science. This purpose has simulated the development of low-temperature high-pressure technique for neutron diffraction study. With benefit of high intensity neutron sources a new diamond anvil cell (DAC) has been invented by I.N. Goncharenko. This device allows us to study neutron diffraction under extreme conditions of pressures up to 50 GPa, temperatures down to 0.1 K and applied magnetic fields up to 7.5 T. We describe the details of this technique in the hope that J-PARC (Japan Proton Accelerator Research Complex) will make an epoch in ultra-high-pressure research. (author)

  8. 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

  9. 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

  10. 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...

  11. A small angle neutron scattering study on the mixtures of pluronic ...

    Indian Academy of Sciences (India)

    cO Indian Academy of Sciences. Vol. 71, No. 5. — journal of. November 2008 physics pp. 1063–1067. A small angle neutron scattering study on the mixtures of pluronic L121 and anionic surfactant AOT. G GHOSH1,∗, V K ASWAL2 and D VARADE3. 1UGC-DAE Consortium for Scientific Research, Mumbai 400 085, India.

  12. 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.)

  13. Inelastic neutron scattering study of lattice dynamics in α-ZnCl

    Indian Academy of Sciences (India)

    Abstract. Inelastic neutron scattering experiments have been carried out to measure the phonon density of states in polycrystalline α-ZnCl2 at Dhruva, Trombay. Lattice dynamical calculations, based on an interatomic potential model, are accomplished to study phonons associated with this otherwise extremely hygroscopic ...

  14. Neutron-scattering studies of a polymer electrolyte, PPO-LiClO4

    DEFF Research Database (Denmark)

    Carlsson, P.; Mattsson, B.; Swenson, J.

    1998-01-01

    The structure and dynamics of a prototype polymer electrolyte, PPO-LiClO4, have been investigated using neutron diffraction (ND) and quasi-elastic neutron scattering (QENS). For comparison, corresponding studies of pure PPO have also been performed. The diffraction data reveal large structural...

  15. 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)

  16. Studying fractal geometry on submicron length scales by small-angle scattering

    International Nuclear Information System (INIS)

    Wong, P.; Lin, J.

    1988-01-01

    Recent studies have shown that internal surfaces of porous geological materials, such as rocks and lignite coals, can be described by fractals down to atomic length scales. In this paper, the basic properties of self-similar and self-affine fractals are reviewed and how fractal dimensions can be measured by small-angle scattering experiments are discussed

  17. Interaction between Humic Acid and Lysozyme, Studied by Dynamic Light Scattering and Isothermal Titration Calorimetry

    NARCIS (Netherlands)

    Tan, Wen Feng; Koopal, Luuk K.; Norde, Willem

    2009-01-01

    Interactions of purified Aldrich humic acid (PAHA) with the protein lysozyme (LSZ) are studied with dynamic light scattering and isothermal titration calorimetry by mixing LSZ and PAHA at various mass ratios. In solution LSZ is positive and PAHA is negative at the investigated pH values. Up to

  18. The defect structure of yttria-stabilized zirconia, studied by quasielastic diffuse neutron scattering

    DEFF Research Database (Denmark)

    Andersen, Niels Hessel; Clausen, Kurt Nørgaard; Hackett, M. A.

    1986-01-01

    The static defect structure of the oxygen ion conductor Y2O3 stabilized zirconia has been studied at room temperature by coherent diffuse neutron scattering from single crystal samples containing nominally 9.4, 12, 15 and 18 mol% Y2O3. There are two principal contributions to the observed diffuse...

  19. 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...

  20. Neutron Scattering Studies of Nanomagnetism and Artificially Structured Materials

    Energy Technology Data Exchange (ETDEWEB)

    Fitzsimmons, M.R.; Bader, S.D.; Borchers, J.A.; Felcher, G.P.; Furdyna, J.K.; Hoffmann, A.; Kortright, J.B.; Schuller, Ivan K.; Schulthess, T.C.; Sinha, S.K.; Toney, M.F.; Weller, D.; Wolf, S.

    2003-02-01

    Nanostructured magnetic materials are intensively studied due to their unusual properties and promise for possible applications. The key issues in these materials relate to the connection between their physical properties (transport, magnetism, mechanical, etc.) and their chemical-physical structure. In principle, a detailed knowledge of the chemical and physical structure allows calculation of their physical properties. Theoretical and computational methods are rapidly evolving so that magnetic properties of nanostructured materials might soon be predicted. Success in this endeavor requires detailed quantitative understanding of the magnetic structure and properties.

  1. Controlling Stimulated Brillouin/Raman Scattering in High Power Fiber Lasers

    Science.gov (United States)

    2017-08-09

    fiber amplifier archetype . 26 Approved for public release. Distribution is unlimited. The fiber was coiled on a 65 cm diameter aluminum spool with...compare to bulk silica [7] and the gB for the Yb- and P2O5-doped silica was 4.3x reduced [12] compared to literature values. A 2x reduction can be...glass interface. Other efficiency metrics for free-space fiber amplifiers that are found in the literature include efficiency with respect to the

  2. Light Scattering Studies of Organic Field Effect Transistors

    Science.gov (United States)

    Adil, Danish

    Organic semiconductors hold a great promise of enabling new technology based on low cost and flexible electronic devices. While much work has been done in the field of organic semiconductors, the field is still quite immature when compared to that of traditional inorganic based devices. More work is required before the full potential of organic field effect transistors (OFETs), organic light emitting diodes (OLEDs), and organic photovoltaics (OPVs) is realized. Among such work, a further development of diagnostic tools that characterize charge transport and device robustness more efficiently is required. Charge transport in organic semiconductors is limited by the nature of the metal-semiconductor interfaces where charge is injected into the semiconductor film and the semiconductor-dielectric interface where the charge is accumulated and transported. This, combined with that fact that organic semiconductors are especially susceptible to having structural defects induced via oxidation, charge transport induced damage, and metallization results in a situation where a semiconductor film's ability to conduct charge can degrade over time. This degradation manifests itself in the electrical device characteristics of organic based electronic devices. OFETs, for example, may display changes in threshold voltage, lowering of charge carrier mobilities, or a decrease in the On/Off ratio. All these effects sum together to result in degradation in device performance. The work begins with a study where matrix assisted pulsed laser deposition (MAPLE), an alternative organic semiconductor thin film deposition method, is used to fabricate OFETs with improved semiconductor-dielectric interfaces. MAPLE allows for the controlled layer-by-layer growth of the semiconductor film. Devices fabricated using this technique are shown to exhibit desirable characteristics that are otherwise only achievable with additional surface treatments. MAPLE is shown to be viable alternative to other

  3. Neutron Scattering Studies of Fundamental Processes in Earth Materials, Final Report

    International Nuclear Information System (INIS)

    McCall, K. R.

    2007-01-01

    The aim of this work was to use neutron scattering techniques to explore the dynamics and structure of water in rock samples. The dynamics of water in rock at low (residual) saturation are directly related to the transport properties of fluids within the host rock. The structure of water in rock may be related to the elastic behavior of the rock, which in many cases is nonlinear and hysteretic. Neutron scattering techniques allow us to study water in intact rock samples at both the molecular and microstructural scales. Our samples were Berea sandstone, Calico Hills and Prow Pass tuffs from Yucca Mountain, NV, and pure samples of the tuff constituents, specifically mordenite and clinoptilolite. We chose Berea sandstone because its macroscopic elastic behavior is known to be highly unusual, and the microscopic mechanisms producing this behavior are not understood. We chose Yucca Mountain tuff, because the fluid transport properties of the geologic structure at Yucca Mountain, Nevada could be relevant to the performance of a high level nuclear waste repository at that site. Neutron scattering methods have a number of properties that are extremely useful for the study of earth materials. In contrast to X-rays, neutrons have very low absorption cross-sections for most elements so that entire bulk samples of considerable size can be 'illuminated' by the neutron beam. Similarly, samples that are optically opaque can be readily investigated by inelastic neutron scattering techniques. Neutrons are equally sensitive to light atoms as to heavy atoms, and can, for example, readily distinguish between Al and Si, neighboring atoms in the periodic table that are difficult to tell apart by X-ray diffraction. Finally, neutrons are particularly sensitive to hydrogen and thus can be used to study the motions, both vibrational and diffusive, of H-containing molecules in rocks, most notably of course, water. Our studies were primarily studies of guest molecules (in our case, water) in

  4. Neutron and photon scattering properties of high density concretes used in radiation therapy facilities: A Monte Carlo study

    Science.gov (United States)

    Mesbahi, Asghar; Khaldari, Rezvan

    2017-09-01

    In the current study the neutron and photon scattering properties of some newly developed high density concretes (HDCs) were calculated by using MCNPX Monte Carlo code. Five high-density concretes including Steel-Magnetite, Barite, Datolite-Galena, Ilmenite-ilmenite, Magnetite-Lead with the densities ranging from 5.11 g/cm3 and ordinary concrete with density of 2.3 g/cm3 were studied in our simulations. The photon beam spectra of 4 and 18 MV from Varian linac and neutron spectra of clinical 18 MeV photon beam was used for calculations. The fluence of scattered photon and neutron from all studied concretes was calculated in different angles. Overall, the ordinary concrete showed higher scattered photons and Datolite-Galena concrete (4.42 g/cm3) had the lowest scattered photons among all studied concretes. For neutron scattering, fluence at the angle of 180 was higher relative to other angles while for photons scattering fluence was maximum at 90 degree. The scattering fluence for photons and neutrons was dependent on the angle and composition of concrete. The results showed that the fluence of scattered photons and neutrons changes with the composition of high density concrete. Also, for high density concretes, the variation of scattered fluence with angle was very pronounced for neutrons but it changed slightly for photons. The results can be used for design of radiation therapy bunkers.

  5. Structural studies of RNA-protein complexes: A hybrid approach involving hydrodynamics, scattering, and computational methods.

    Science.gov (United States)

    Patel, Trushar R; Chojnowski, Grzegorz; Astha; Koul, Amit; McKenna, Sean A; Bujnicki, Janusz M

    2017-04-15

    The diverse functional cellular roles played by ribonucleic acids (RNA) have emphasized the need to develop rapid and accurate methodologies to elucidate the relationship between the structure and function of RNA. Structural biology tools such as X-ray crystallography and Nuclear Magnetic Resonance are highly useful methods to obtain atomic-level resolution models of macromolecules. However, both methods have sample, time, and technical limitations that prevent their application to a number of macromolecules of interest. An emerging alternative to high-resolution structural techniques is to employ a hybrid approach that combines low-resolution shape information about macromolecules and their complexes from experimental hydrodynamic (e.g. analytical ultracentrifugation) and solution scattering measurements (e.g., solution X-ray or neutron scattering), with computational modeling to obtain atomic-level models. While promising, scattering methods rely on aggregation-free, monodispersed preparations and therefore the careful development of a quality control pipeline is fundamental to an unbiased and reliable structural determination. This review article describes hydrodynamic techniques that are highly valuable for homogeneity studies, scattering techniques useful to study the low-resolution shape, and strategies for computational modeling to obtain high-resolution 3D structural models of RNAs, proteins, and RNA-protein complexes. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  6. Study of impurities in ferromagnetic alloys by neutron scattering and Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Madhav Rao, L.

    1977-01-01

    Neutron scattering techniques have been extensively used to investigate ferromagnetic dilute alloys and have provided unique answers in many cases. One such case is the determination of the distribution of the magnetic moments among the constituent atoms and the extent and nature of the perturbation around the impurity atoms themselves. During the last few years, polarised neutrons have provided a much more powerful and reliable aid in separating the magnetic impurity scattering from the background of the 'host' scattering, revealing thus more delicate features of these magnetic distributions. The general features of these distributions are discussed and compared with existing theories. Unlike in the case of neutron scattering, the investigation of the impurity problem by Moessbauer Effect has, for obvious reasons, been confined to iron based dilute alloys. Moessbauer Effect has been proved to be a useful tool to study local charge and spin density distributions around the impurity atom. Comparison of the magnetic hyperfine fields and bulk magnetization as a function of the impurity concentration and the study of the temperature dependence of the magnetic hyperfine fields at the various sites have led to interesting conclusions of the 'itinerancy' of ferromagnetism in iron. (author)

  7. Structural Significance of Lipid Diversity as Studied by Small Angle Neutron and X-ray Scattering

    Directory of Open Access Journals (Sweden)

    Norbert Kučerka

    2015-09-01

    Full Text Available We review recent developments in the rapidly growing field of membrane biophysics, with a focus on the structural properties of single lipid bilayers determined by different scattering techniques, namely neutron and X-ray scattering. The need for accurate lipid structural properties is emphasized by the sometimes conflicting results found in the literature, even in the case of the most studied lipid bilayers. Increasingly, accurate and detailed structural models require more experimental data, such as those from contrast varied neutron scattering and X-ray scattering experiments that are jointly refined with molecular dynamics simulations. This experimental and computational approach produces robust bilayer structural parameters that enable insights, for example, into the interplay between collective membrane properties and its components (e.g., hydrocarbon chain length and unsaturation, and lipid headgroup composition. From model studies such as these, one is better able to appreciate how a real biological membrane can be tuned by balancing the contributions from the lipid’s different moieties (e.g., acyl chains, headgroups, backbones, etc..

  8. Structural Significance of Lipid Diversity as Studied by Small Angle Neutron and X-ray Scattering.

    Science.gov (United States)

    Kučerka, Norbert; Heberle, Frederick A; Pan, Jianjun; Katsaras, John

    2015-09-21

    We review recent developments in the rapidly growing field of membrane biophysics, with a focus on the structural properties of single lipid bilayers determined by different scattering techniques, namely neutron and X-ray scattering. The need for accurate lipid structural properties is emphasized by the sometimes conflicting results found in the literature, even in the case of the most studied lipid bilayers. Increasingly, accurate and detailed structural models require more experimental data, such as those from contrast varied neutron scattering and X-ray scattering experiments that are jointly refined with molecular dynamics simulations. This experimental and computational approach produces robust bilayer structural parameters that enable insights, for example, into the interplay between collective membrane properties and its components (e.g., hydrocarbon chain length and unsaturation, and lipid headgroup composition). From model studies such as these, one is better able to appreciate how a real biological membrane can be tuned by balancing the contributions from the lipid's different moieties (e.g., acyl chains, headgroups, backbones, etc.).

  9. Neutron scattering study of the dynamics of a polymer melt under nanoscopic confinement.

    Science.gov (United States)

    Krutyeva, Margarita; Martin, Jaime; Arbe, Arantxa; Colmenero, Juan; Mijangos, Carmen; Schneider, Gerald J; Unruh, Tobias; Su, Yixi; Richter, Dieter

    2009-11-07

    Poly(ethylene oxide) confined in an anodic aluminum oxide solid matrix has been studied by different neutron scattering techniques in the momentum transfer (Q) range 0.2neutron intensity scattered for two orientations of the sample with respect to the incident beam, for which the Q direction was either parallel or perpendicular to the pores for a scattering angle of 90 degrees . Diffuse neutron scattering at room temperature has shown that the aluminum oxide has amorphous structure and the polymer in the nanoporous matrix is partially crystallized. Concerning the dynamical behavior, for Qhigh-Q limit we observe a slowing down of the dynamics with respect to the bulk behavior that evidences an effect of confinement. This effect is more pronounced for molecular displacements perpendicular to the pore axis than for parallel displacements. Our results clearly rule out the strong corset effect proposed for this polymer from nuclear magnetic resonance (NMR) studies and can be rationalized by assuming that the interactions with the pore walls affect one to two adjacent monomer monolayers.

  10. 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.

  11. 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)

  12. 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)

  13. 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

  14. X-ray and neutron scattering studies of complex confined fluids.

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, S. K.

    1999-08-04

    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.

  15. 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.

  16. Study on the influence of the scattered radiation in the industrial transmission gamma tomography

    International Nuclear Information System (INIS)

    Kim, Jongbum; Jung, Sunghee; Kim, Jinseop; Lee, Nayoung; Cho, Gyuseong

    2008-01-01

    The effect of scattered radiation on the transmitted gamma ray signal should be carefully taken into account because it certainly affects the quality of reconstructed tomography images. Therefore this effect was evaluated with different counting modes and gamma energies. For less dense objects such as wood and plastics, the build-up effect can be ignored and 137 Cs can yield the better result than 60 Co. On the contrary, for the relatively heavy material such as oil and metal the scattered radiation effect of 137 Cs source should be considered because the build-up effect is more serious than 60 Co. It was also found that the image quality gets better when the count data of photo-peak were used rather than the total counts from the full spectrum. The image improvement technique using precise weight matrix calculation method was suggested to remove the influence of the scattered radiation on the reconstructed image quality. From the experiment, it was concluded that the effect of scattered radiation on the image quality is varied depending on the material composition and radiation energy. Before the implementation in the field, normally the information of the process material is available so the optimal measurement condition can be predetermined on the basis of this study. The additional data processing method is also expected to improve the reconstructed image quality further. (author)

  17. An experimental feasibility study on the use of scattering foil free beams for modulated electron radiotherapy.

    Science.gov (United States)

    Connell, T; Alexander, A; Evans, M; Seuntjens, J

    2012-06-07

    The potential benefit of using scattering foil free beams for delivery of modulated electron radiotherapy is investigated in this work. Removal of the scattering foil from the beamline showed a measured bremsstrahlung tail dose reduction just beyond R(p) by a factor of 12.2, 6.9, 7.4, 7.4 and 8.3 for 6, 9, 12, 16 and 20 MeV beams respectively for 2 × 2 cm(2) fields defined on-axis when compared to the clinical beamline. Monte Carlo simulations were matched to measured data through careful tuning of source parameters and the modification of certain accelerator components beyond the manufacturer's specifications. An accelerator model based on the clinical beamline and one with the scattering foil removed were imported into a Monte Carlo-based treatment planning system (McGill Monte Carlo Treatment Planning). A treatment planning study was conducted on a test phantom consisting of a PTV and two distal organs at risk (OAR) by comparing a plan using the clinical beamline to a plan using a scattering foil free beamline. A DVH comparison revealed that for quasi-identical target coverage, the volume of each OAR receiving a given dose was reduced, thus reducing the dose deposited in healthy tissue.

  18. Small angle neutron scattering study of nanostructure in permanent magnet materials and coercivity mechanism

    International Nuclear Information System (INIS)

    Kato, Hiroaki

    2008-01-01

    Small angle neutron scattering study was performed in sintered Nd-Fe-B permanent magnets. The 99% enriched 11 B isotope was used to avoid high neutron absorption of 10 B in natural boron. In all the samples examined, the intensity of scattered neutrons was proportional to the q -4 for q -1 , irrespective of the direction of q. For q>0.5 nm -1 , on the other hand, the intensity was markedly higher than that expected from the q -4 dependence. These results show that there exists a neutron scatterer with a dimension of less than 10 nm, which is considered to be a Nd-rich grain boundary phase in the matrix of Nd 2 Fe 14 B phase. In the sample with Al and Cu additives, we observed a small but finite increase of intensity as compared with the sample without Al and Cu additives for the q range of 0.1 -1 . Since Al- and Cu-containing samples have higher coercivity, this result suggests that there is a correlation between the density of neutron scatterer at a Nd-rich grain boundary and the coercivity. (author)

  19. 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.

  20. Small-angle neutron scattering study of a monoclonal antibody using free-energy constraints.

    Science.gov (United States)

    Clark, Nicholas J; Zhang, Hailiang; Krueger, Susan; Lee, Hyo Jin; Ketchem, Randal R; Kerwin, Bruce; Kanapuram, Sekhar R; Treuheit, Michael J; McAuley, Arnold; Curtis, Joseph E

    2013-11-14

    Monoclonal antibodies (mAbs) contain hinge-like regions that enable structural flexibility of globular domains that have a direct effect on biological function. A subclass of mAbs, IgG2, have several interchain disulfide bonds in the hinge region that could potentially limit structural flexibility of the globular domains and affect the overall configuration space available to the mAb. We have characterized human IgG2 mAb in solution via small-angle neutron scattering (SANS) and interpreted the scattering data using atomistic models. Molecular Monte Carlo combined with molecular dynamics simulations of a model mAb indicate that a wide range of structural configurations are plausible, spanning radius of gyration values from ∼39 to ∼55 Å. Structural ensembles and representative single structure solutions were derived by comparison of theoretical SANS profiles of mAb models to experimental SANS data. Additionally, molecular mechanical and solvation free-energy calculations were carried out on the ensemble of best-fitting mAb structures. The results of this study indicate that low-resolution techniques like small-angle scattering combined with atomistic molecular simulations with free-energy analysis may be helpful to determine the types of intramolecular interactions that influence function and could lead to deleterious changes to mAb structure. This methodology will be useful to analyze small-angle scattering data of many macromolecular systems.

  1. 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

  2. Applications of phase conjugate mirror to Thomson scattering diagnostics (invited)

    International Nuclear Information System (INIS)

    Hatae, T.; Naito, O.; Nakatsuka, M.; Yoshida, H.

    2006-01-01

    A high performance phase conjugate mirror based on stimulated Brillouin scattering (SBS-PCM) has been applied to the Thomson scattering system in the JT-60U tokamak for the first time in order to improve the measurement performance. A SBS-PCM realized a high reflectivity of 95% at a high input power of 145 W (2.9 J, 50 Hz). Using the SBS-PCM, two methods have been developed to increase the intensity of scattered light. For the first method, we have developed a new optical design to provide a double-pass scattering method with the SBS-PCM. A laser beam passing through the plasma is reflected by the SBS-PCM. The reflected beam passes the plasma again along the same path by means of the phase conjugation of the optically nonlinear stimulated Brillouin scattering process. The double-pass Thomson scattering method using the SBS-PCM has demonstrated an increase of the scattered light by a factor of 1.6 compared with the single-pass scattering method in JT-60U. A multipass Thomson scattering method in which the laser beam can be confined between a couple of SBS-PCMs is also proposed. It is estimated that the multipass scattering method generates the scattered light more than several times as large as that of the single-pass scattering method. For the second method, a high-average-power yttrium aluminum garnet (Nd:YAG) laser system has been developed using the SBS-PCM. The SBS-PCM effectively compensated thermal degradation at two amplifier lines, and the average power was increased by a factor of >8 from 45 W (1.5 J, 30 Hz) to 373 W (7.46 J, 50 Hz). A Nd:YAG laser (5 J, 100 Hz) for the edge Thomson scattering in International Thermonuclear Experimental Reactor (ITER) has been designed based on the result

  3. Resonant X-ray Raman scattering on molecules: A benchmark study on HCl

    International Nuclear Information System (INIS)

    Carniato, Stephane; Taieb, Richard; Journel, Loic; Guillemin, Renaud; Stolte, Wayne C.; Lindle, Dennis W.; Gel'mukhanov, Faris; Simon, Marc

    2010-01-01

    Resonant X-ray Raman scattering is a powerful tool to study molecular dynamics and subtle chemical effects like the molecular field beyond vibrational and lifetime limitations. Using this technique in the tender X-ray region, gas phase HCl is studied as a benchmark molecule for other compounds like freons, which play an important role in physical-chemical properties of the ozone layer of atmosphere.

  4. Resonant X-ray Raman scattering on molecules: A benchmark study on HCl

    Energy Technology Data Exchange (ETDEWEB)

    Carniato, Stephane [UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France); CNRS, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France); Taieb, Richard, E-mail: richard.taieb@upmc.f [UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France); CNRS, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France); Journel, Loic; Guillemin, Renaud [UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France); CNRS, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France); Stolte, Wayne C.; Lindle, Dennis W. [Department of Chemistry, University of Nevada, Las Vegas, NV 89154-4003 (United States); Gel' mukhanov, Faris [Theoretical Chemistry, Roslagstullsbacken 15, Royal Institute of Technology, S-106 91 Stockholm (Sweden); Simon, Marc [UPMC Univ Paris 06, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France); CNRS, UMR 7614, Laboratoire de Chimie Physique Matiere et Rayonnement, F-75005 Paris (France)

    2010-08-15

    Resonant X-ray Raman scattering is a powerful tool to study molecular dynamics and subtle chemical effects like the molecular field beyond vibrational and lifetime limitations. Using this technique in the tender X-ray region, gas phase HCl is studied as a benchmark molecule for other compounds like freons, which play an important role in physical-chemical properties of the ozone layer of atmosphere.

  5. A review on the study of polymer properties by Small Angle Neutron Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Baek Seok; Lee, Chang Hee; Sim, Hae Seop; Lee, Jung Sool [Korea Atomic Energy Research Institute, Daeduk (Korea, Republic of); Kim, Hong Doo [Kyunghee Univ., Seoul (Korea, Republic of); Kim, Eu Gene [Hongik Univ., Seoul (Korea, Republic of); Cha, Kuk Heon [Seoul National Univ., Seoul (Korea, Republic of)

    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

  6. 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

  7. 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)

  8. 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.

  9. 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)

  10. Inelastic Neutron Scattering and Molecular Dynamics Determination of the Interaction Potential in Liquid CD4

    International Nuclear Information System (INIS)

    Guarini, E.; Barocchi, F.; Sampoli, M.; Venturi, G.; Bafile, U.

    2007-01-01

    Anisotropic interactions of liquid CD 4 are studied in detail by comparison of inelastic neutron Brillouin scattering data with molecular dynamics simulations using up to four different models of the methane site-site potential. We demonstrate that the experimental dynamic structure factor S(Q,ω) acts as a highly discriminating quantity for possible interaction schemes. In particular, the Q evolution of the spectra enables a selective probing of the short- and medium-range features of the anisotropic potentials. We show that the preferential configuration of methane dimers at liquid densities can thus be discerned by analyzing the orientation-dependent model potential curves, in light of the experimental and simulation results

  11. Probing the pairing symmetry of the iron pnictides with electronic Raman scattering

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, G.R.

    2010-04-29

    An important issue in the study of the iron-arsenic based superconductors is the symmetry of the superconducting gap, a problem complicated by multiple gaps on different Fermi surface sheets. Electronic Raman scattering is a flexible bulk probe which allows one in principle to determine gap magnitudes and test for gap nodes in different regions of the Brillouin zone by employing different photon polarization states. Here we calculate the clean Raman intensity for A{sub 1g}, B{sub 1g} and B{sub 2g} polarizations, and discuss the peak structures and low-energy power laws which might be expected for several popular models of the superconducting gap in these systems.

  12. 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.

  13. Structure and dynamics of CdTe studied by X-ray and neutron scattering

    Science.gov (United States)

    Stone, Matthew; Niedziela, Jennifer

    2015-03-01

    We present x-ray diffraction and inelastic neutron scattering studies of the structure and lattice dynamics of commercially available cadmium telluride. We also present complementary density functional theory calculations. The x-ray data show a subtle structural transition is present near 80 K, which manifests also in the measured phonon density of states. Refinement of the structure above and below the transition temperature shows no change to the long-range ordered structure. The inelastic neutron scattering studies were performed using an isotopically un-enriched sample of CdTe, which possesses a high cross section for thermal neutron absorption. The neutron portion of the study was performed with a thin-plate geometry in the reflection condition at the ARCS instrument at the SNS, showing the high flux of the instrument makes possible lattice dynamics studies of materials with high thermal neutron absorption. Single crystal and powder inelastic neutron scattering measurements will be presented. Current interpretation of the nature of the transition and future studies will be discussed. This research at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy.

  14. Electron Scattering

    International Nuclear Information System (INIS)

    Li, Xiaodong; Lee, Kyong Sei; Shaw, J.J.; Bahri, C.

    1990-01-01

    Electron scattering is one of the best probes available to us to probe the nucleus. It has revealed to us, with unprecedented accuracy, the charge and current distributions of nuclei. It has provided us with positive evidence for meson exchange currents. It was used to 'discover' the quark and it revealed to us that nucleons may be modified in the nuclear environment (EMC Effect). In short, electron scattering has revolutionized the study of nuclear physics. Several recent developments will insure that electron beams which will soon become availabe at CEBAF, Bates and elsewhere will make high-precision coincidence experiments possible. As the technology is becoming available, we are just beginning to exploit polarization degrees of freedom in our experiments. In this paper, we will introduce the formalism of electron scattering, review what we have learned in the past and look ahead toward the future

  15. Precision of ion temperature measurements in a tokamak plasma using collective Thomson scattering: a numerical study

    International Nuclear Information System (INIS)

    Krug, P.A.

    1989-08-01

    A numerical simulation has been performed to investigate the precision of a T i -measurement of a tokamak plasma via collective Thomson scattering at 385 μm. The study is based on a parameter and data set referring to an experiment that has been carried out at the TCA tokamak using a pulsed D 2 O laser and a heterodyne receiver system. Apart from limitations due to the signal-to-noise ratio of the detection system, we investigate the influence of uncertainties in various plasma parameters required for the T i -evaluation from a scattered spectrum. In the experiment typical relative errors of ± 25% have been already been obtained, but careful optimization of the system, taking into account the results of this study, and further technical improvements should allow to reduce this limit to about ±10% for the plasma conditions considered. (author) 17 figs., 1 tab., 6 refs

  16. 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

  17. 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)

  18. Dynamics of water in deoxyribonucleic acid studied by neutron inelastic scattering

    International Nuclear Information System (INIS)

    Walder, V.S.; Vinhas, L.A.; Fulfaro, R.

    1980-01-01

    In order to study the dynamics of water present in biological molecules neutron inelastic scattering measurements were performed on natural and dehydrated DNA samples, using a cold neutron time-of-flight spectrometer. The water frequency spectrum obtained by difference from the natural and the dehydrated DNA spectra indicates that water molecule motions in the helicoidal DNA structure are quite similar to those in liquid water. (Author) [pt

  19. 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)

  20. Small angle neutron scattering study of ageing process in an Al-Mg-Si alloy

    International Nuclear Information System (INIS)

    Abis, S.; Fiorini, P.; Boeuf, A.; Caciuffo, R.; Crico, S.

    1984-01-01

    Small angle neutron scattering (SANS) measurements were performed on polycrystalline samples of high purity Al-Mg (0.72%)-Si (0.34%) alloy. The effect of different ageing temperature was observed and the results compared with information obtained using differen technique such as resistivity measurements and transmission electron microscopy. The results give useful information on the validity of SANS for the study of complex Al alloy

  1. 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

  2. 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

  3. 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.

  4. A Study of Diffractive Scattering with the ATLAS and ALFA Experiment

    CERN Document Server

    AUTHOR|(CDS)2097773

    This thesis presents a study of diffractive scattering of high-energy protons. Hadronic diffraction is not well-understood and many alternative approaches exist. The Monte Carlo event generator Pythia 8 follows a Pomeron-based approach, where the invariant mass of the diffractive system and the squared momentum transfer $t$ of the system is set up according to a phenomenological Pomeron flux parameterization, which is parameterized by the super-critical Pomeron trajectory, $\\alpha(t) = 1 + \\varepsilon + \\alpha' t$, where the intercept parameter $\\varepsilon$ and the slope parameter $\\alpha'$ can be tuned by the user. A fast detector response simulation of the ALFA and ATLAS detectors has been developed in the Rivet toolkit for the purposes of this thesis. The developed simulation framework is able to handle the beam transport of diffractively scattered protons as well as impose the kinematic acceptance of the ALFA detector which was found to be approximately $\\xi \\lesssim 0.22$, with a pseudorapidity coverag...

  5. Micro-Raman scattering studies of Ge-Sb-Te bulk crystals and nanoparticles

    International Nuclear Information System (INIS)

    Cho, E.; Yoon, S.; Yoon, H. R.; Jo, W.

    2006-01-01

    We measured micro-Raman scattering spectra of commercially available Ge-Sb-Te (GST) bulk crystals and GST nanoparticles which were synthesized using a pulsed laser ablation method. The lack of the amorphous Te-Te stretching mode near 150 cm -1 from the Raman spectrum of the bulk sample indicated that the sample was well-crystallized. We also measured GST nanoparticles with different growth conditions, from which we could get information towards the optimal growth conditions for better crystallinity of the GST nanoparticles. Our results suggest that through local structural information, micro-Raman scattering spectroscopy can be used to study the phases and the phase changes in the GST bulk crystals and nanoparticles which is being developed for low-power non-volatile memory applications.

  6. Dynamic light scattering study of the effect of Mg2+ and ATP on synthetic myosin filaments

    Science.gov (United States)

    Fujime, Satoru; Takayama, Sei-ichi

    1995-01-01

    The dynamic light scattering (DLS) method provides us with information about the apparent diffusion coefficient, Dapp, as well as the static scattering intensity, Is. For long but thin rods with length L and diameter d (i.e., KL >> 1 but Kd different from that of Is. By means of DLS were studied synthetic myosin filaments of vertebrate skeletal muscle in solution at pH 8.3. It appeared that Mg2+ ions induced lengthening and thickening of the filaments whereas ATP (and ADP) induced shortening (depolymerization) of the filaments. When ATP was added to the filament preparation in the presence of Mg2+ ions, thinning of the filaments (or splitting into subfilaments) occurred prior to shortening (depolymerization).

  7. 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

  8. Neutron scattering study of adsorption in porous MCM-41 silica{sup 1}

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.J.C. [Queen' s Univ., Chemistry Dept., Kingston, ON (Canada); Evans, M.J.B. [Royal Military Coll., Dept. of Chemistry and Chemical Engineering, Kingston, ON (Canada); Tun, Z., E-mail: zin.tun@nrc.gc.ca [Canadian Neutron Beam Centre, National Research Council Canada, Chalk River, ON (Canada)

    2010-10-15

    Adsorption of n-pentane on MCM-41 silica has been studied by neutron scattering on both the adsorption and desorption isotherms. Adsorption takes place without hysteresis in either the isotherm or the neutron scattering profile. Adsorption of contrast-matched pentane in porous MCM-41 silica at first increases the intensity of the (10) Bragg peak but reduces the (11) and (20) peaks, and as the pores are filled the intensities of all Bragg peaks are reduced to zero. The SANS background has a 1/Q dependence, typical of a material prepared with templates of one-dimensional character (cylinders). The initial increase of (10) intensity allows estimation of the cylindrical pore diameter to be 37 AÅ based on the variation of form factor as a function of the cylinder radius. (author)

  9. Study of the low-energy neutron inelastic scattering in deformed transitional nuclei: 186W

    International Nuclear Information System (INIS)

    Diaz, J.R.F.; Solorzano, R.C.

    1983-01-01

    A study of inelastic neutron scattering by the nucleus 186 W at an incident energy of 2.75 MeV using the coupled-channel method has been made. Consideration is made of the 2 + (0.122 MeV), 4 + (0.3966 MeV), 2 + (0.7375 MeV), 3 + (0.8618 MeV) and 4 + (1.031 MeV) excited states. It is shown that in this energy range the process may be described satisfactorily by the Davydov-Filippov model, considering 186 W as a deformed nucleus with non-axial symmetry, given the quadrupole and hexadecapole deformations. The scattering process through the compound nucleus is calculated according to the Hauser-Feshbach formula. It is shown that the presence of direct processes may be partly due to the non-axiality of 186 W. (author)

  10. 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)

  11. A small angle neutron scattering study of isolated nanopores in a ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Raut Dessai, R. [Department of Physics, Goa University, Taleigao Plateau, Goa 403 206 (India); Desa, J.A.E., E-mail: erwindesa@gmail.com [Department of Physics, Goa University, Taleigao Plateau, Goa 403 206 (India); Sen, D.; Mazumder, S. [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    2015-04-15

    Highlights: • Isolated nanopores in ceramic have been studied by SANS contrast variation. • The measured intensity was solely due to the presence of the isolated pores. • Concentration of isolated pores is substantially reduced at higher temperatures. • SANS is an effective tool to estimate isolated nanometric pores. - Abstract: The isolated pores in a silica ceramic sintered at 1073 K and 1273 K have been studied by small angle neutron scattering using the technique of scattering contrast factor variation. A mixture of H{sub 2}O and D{sub 2}O which matched the scattering length density of the ceramic matrix was introduced into the pores of the sample. The connected pores were thus contrast matched and hence the measured intensity was solely due to the presence of the isolated pores having no contrast matched liquid inside. Analysis of the data yielded a widely separated bi-modal distribution (with modes at ∼170 nm and 35 nm) of nanopores in the compacts. A qualitative model for the sintering in this ceramic is proposed where densification of the matrix occurs by annihilation of smaller pores. However, this is associated with enhancement in the number of larger pores through pore coalescence. In this description the connected pores both – macro and nano – increase in number – simultaneous with a decrease in numbers of isolated pores.

  12. A small angle neutron scattering study of isolated nanopores in a ceramic

    International Nuclear Information System (INIS)

    Raut Dessai, R.; Desa, J.A.E.; Sen, D.; Mazumder, S.

    2015-01-01

    Highlights: • Isolated nanopores in ceramic have been studied by SANS contrast variation. • The measured intensity was solely due to the presence of the isolated pores. • Concentration of isolated pores is substantially reduced at higher temperatures. • SANS is an effective tool to estimate isolated nanometric pores. - Abstract: The isolated pores in a silica ceramic sintered at 1073 K and 1273 K have been studied by small angle neutron scattering using the technique of scattering contrast factor variation. A mixture of H 2 O and D 2 O which matched the scattering length density of the ceramic matrix was introduced into the pores of the sample. The connected pores were thus contrast matched and hence the measured intensity was solely due to the presence of the isolated pores having no contrast matched liquid inside. Analysis of the data yielded a widely separated bi-modal distribution (with modes at ∼170 nm and 35 nm) of nanopores in the compacts. A qualitative model for the sintering in this ceramic is proposed where densification of the matrix occurs by annihilation of smaller pores. However, this is associated with enhancement in the number of larger pores through pore coalescence. In this description the connected pores both – macro and nano – increase in number – simultaneous with a decrease in numbers of isolated pores

  13. Phase separation and ordering process in Al-Li alloys studied by small-angle neutron scattering and neutron diffraction

    International Nuclear Information System (INIS)

    Furusaka, M.; Fujikawa, S.I.

    1993-01-01

    To study phase separation kinetics of Al-9.5at.%Li polycrystalline alloys in which precipitates have ordered Al 3 Li (δ') structure, profile analysis of small-angle neutron scattering and superlattice reflections (100) and (110) were done. A small-angle scattering instrument and a triple-axis spectrometer in elastic mode were used in the measurements. Strong texture was observed in the reflections. Therefore, measurements were done using the crystal orientation where the intensity of the reflection was at the maximum. Profiles of small-angle scattering and superlattice reflections were almost identical at higher momentum transfer side. At lower momentum transfer side, small-angle scattering showed interference effects, but superlattice reflection did not show any sign of interference. Integrated intensities of superlattice reflections were obtained and compared with small-angle scattering intensity. The order parameter was not saturated in the δ' precipitates at the early stage of the phase separation process

  14. Characterization of red blood cells (RBCs) using dual Brillouin/Raman micro-spectroscopy

    Science.gov (United States)

    Meng, Zhaokai; Bustamante-Lopez, Sandra C.; Yakovlev, Vladislav V.; Meissner, Kenith E.

    2016-04-01

    Erythrocytes, or red blood cells, transport oxygen to and carbon dioxide from the body's tissues and organs. Red blood cell mechanical properties are altered in a number of diseases such as sickle cell anaemia and malaria. Additionally, mechanically modified red blood cell ghosts are being considered as a long-term, biocompatible carrier for drug delivery and for blood analyte sensing. Brillouin spectroscopy enables viscoelastic characterization of samples at the microscale. In this report, Brillouin spectroscopy is applied to characterize the mechanical properties of red blood cells and red blood cell ghosts.

  15. 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

  16. 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.

  17. 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.

  18. 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

  19. 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

    2012-02-15

    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.

  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