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Sample records for gamma anisotropy measurements

  1. Shaped scintillation detector systems for measurements of gamma ray flux anisotropy

    NASA Technical Reports Server (NTRS)

    Trombka, J. I.; Vette, J. I.; Stecker, F. W.; Eller, E. L.; Wildes, W. T.

    1973-01-01

    The detection efficiencies of cylindrical detectors for various gamma ray photon angular distributions were studied in the energy range from .10 Mev to 15 Mev. These studies indicate that simple detector systems on small satellites can be used to measure flux anisotropy of cosmic gamma rays and the angular distribution of albedo gamma rays produced in planetary atmospheres. The results indicate that flat cylindrical detectors are most suitable for measuring flux anisotropy because of their angular response function. A general method for calculating detection efficiencies for such detectors is presented.

  2. Anisotropies in the Diffuse Gamma-Ray Background Measured by the Fermi LAT

    NASA Technical Reports Server (NTRS)

    Ferrara, E. C.; McEnery, J. E.; Troja, E.

    2012-01-01

    The contribution of unresolved sources to the diffuse gamma-ray background could induce anisotropies in this emission on small angular scales. We analyze the angular power spectrum of the diffuse emission measured by the Fermi LAT at Galactic latitudes absolute value of b > 30 deg in four energy bins spanning 1 to 50 GeV. At multipoles l >= 155, corresponding to angular scales approx < 2 deg, angular power above the photon noise level is detected at > 99.99% CL in the 1-2 GeV, 2- 5 GeV, and 5- 10 GeV energy bins, and at > 99% CL at 10-50 GeV. Within each energy bin the measured angular power takes approximately the same value at all multipoles l >= 155, suggesting that it originates from the contribution of one or more unclustered source populations. The amplitude of the angular power normalized to the mean intensity in each energy bin is consistent with a constant value at all energies, C(sub p) / (I)(exp 2) = 9.05 +/- 0.84 x 10(exp -6) sr, while the energy dependence of C(sub p) is consistent with the anisotropy arising from one or more source populations with power-law photon spectra with spectral index Gamma (sub s) = 2.40 +/- 0.07. We discuss the implications of the measured angular power for gamma-ray source populations that may provide a contribution to the diffuse gamma-ray background.

  3. A degree scale anisotropy measurement of the cosmic microwave background near the star Gamma Ursae Minoris

    NASA Technical Reports Server (NTRS)

    Gundersen, J. O.; Clapp, A. C.; Devlin, M.; Holmes, W.; Fischer, M. L.; Meinhold, P. R.; Lange, A. E.; Lubin, P. M.; Richards, P. L.; Smoot, G. F.

    1993-01-01

    Results from a search for anisotropy in the cosmic microwave background (CMB) are presented from the third flight of the Millimeter-wave Anisotropy experiment. The CMB observation occurred over 1.37 hours and covered a 6.24 sq deg area of the sky where very little foreground emission is expected. Significant correlated structure is observed at 6 and 9/cm. At 12/cm we place an upper limit on the structure. The relative amplitudes at 6, 9, and 12/cm are consistent with a CMB spectrum. The spectrum of the structure is inconsistent with thermal emission from known forms of interstellar dust. Synchrotron and free-free emission would both require unusually flat spectral indices at cm wavelengths in order to account for the amplitude of the observed structure. Although known systematic errors are not expected to contribute significantly to any of the three optical channels, excess sidelobe contamination cannot be definitively ruled out. If all the structure is attributed to CMB anisotropy, a value of the weighted rms of the 6 and 9/cm channels of Delta T/T(CMB) = 4.7 +/- 0.8 x 10 exp -5 (+/- 1 sigma) was measured. If the CMB anisotropy is assumed to have a Gaussian autocorrelation function with a coherence angle of 25 arcmin, then the most probable value is Delta T/T(CMB) = 4.2 +1.7 or -1.1 x 10 exp -5, where the +/- refers to the 95 percent confidence limits.

  4. Constraints on the annihilation cross section of dark matter particles from anisotropies in the diffuse gamma-ray background measured with Fermi-LAT

    NASA Astrophysics Data System (ADS)

    Ando, Shin'ichiro; Komatsu, Eiichiro

    2013-06-01

    Annihilation of dark matter particles in cosmological halos (including the halo of the Milky Way) contributes to the diffuse gamma-ray background (DGRB). As this contribution will appear anisotropic in the sky, one can use the angular power spectrum of anisotropies in the DGRB to constrain the properties of dark matter particles. By comparing the updated analytic model of the angular power spectrum of the DGRB from dark matter annihilation with the power spectrum recently measured from the 22-month data of the Fermi Large Area Telescope (LAT), we place upper limits on the annihilation cross section of dark matter particles as a function of dark matter masses. We find that the current data exclude ⟨σv⟩≳10-25cm3s-1 for annihilation into bb¯ at the dark matter mass of 10 GeV, which is a factor of 3 times larger than the canonical cross section. The limits are weaker for larger dark matter masses. The limits can be improved further with more Fermi-LAT data as well as by using the power spectrum at lower multipoles (ℓ≲150), which are currently not used due to a potential Galactic foreground contamination.

  5. Gamma-ray anisotropies from decaying dark matter

    NASA Astrophysics Data System (ADS)

    Weniger, C.

    2011-06-01

    Many theoretically well-motivated models predict the decay of dark matter with lifetimes much longer than the age of the universe. This can potentially lead to peculiar features in the observed cosmic-ray fluxes. In particular the gamma-ray channel, which carries directional information, is promising for dark matter searches, since it is sensitive to the underlying source distribution. We will discuss the peculiar dipole-like anisotropy of prompt gamma-ray radiation from dark matter decay inside our galaxy, as well as the angular power-spectrum of gamma-rays from dark matter decay outside of our galaxy. We will comment on the experimental detectability of such anisotropies.

  6. Hardening anisotropy of {gamma}/{gamma}{prime} superalloy single crystals. 2: Numerical analysis of heterogeneity effects

    SciTech Connect

    Estevez, R.; Hoinard, G.; Franciosi, P.

    1997-04-01

    In the first part of this study, the {gamma}/{gamma}{prime} superalloy single crystals yield stress and hardening anisotropy were experimentally estimated at 650 C, assuming homogeneous plasticity, G. Hoinard, R. Estevez and P. Franciosi, Acta Metall. 43, 1593 (1995). Here alloy morphology is regarded in two different ways: first as a two-phase anisotropic material with a uniform {gamma} matrix, describing the {gamma}{prime} precipitates arrangement with the help of an elementary pattern of inclusions; then treating the {gamma} matrix as a three (geometrical) phase medium, i.e., the three families of orthogonal {gamma} layers separating the precipitates, to estimate the matrix behavior heterogeneity in a 4-phase modelling of the alloy. Both {gamma} and {gamma}{prime} phases are treated as elastic-plastic crystalline media deforming by octahedral and cubic slip, and the models are based on the self consistent approximation. The alloy elasticity limit, internal stresses and hardening anisotropy are discussed with regard to the chosen behavior description for each phase, and behavior simulations are compared to experimental information.

  7. Measuring anisotropies in the cosmic neutrino background

    NASA Astrophysics Data System (ADS)

    Lisanti, Mariangela; Safdi, Benjamin R.; Tully, Christopher G.

    2014-10-01

    Neutrino capture on tritium has emerged as a promising method for detecting the cosmic neutrino background (C ν B ). We show that relic neutrinos are captured most readily when their spin vectors are antialigned with the polarization axis of the tritium nuclei and when they approach along the direction of polarization. As a result, C ν B observatories may measure anisotropies in the cosmic neutrino velocity and spin distributions by polarizing the tritium targets. A small dipole anisotropy in the C ν B is expected due to the peculiar velocity of the lab frame with respect to the cosmic frame and due to late-time gravitational effects. The PTOLEMY experiment, a tritium observatory currently under construction, should observe a nearly isotropic background. This would serve as a strong test of the cosmological origin of a potential signal. The polarized-target measurements may also constrain nonstandard neutrino interactions that would induce larger anisotropies and help discriminate between Majorana versus Dirac neutrinos.

  8. Fluorescence anisotropy measurements under shock compression

    NASA Astrophysics Data System (ADS)

    Wang, Jue; Bassett, Will; Banishev, Alexandr; Dlott, Dana

    2015-06-01

    Fluorescence anisotropy measurements, where the parallel and perpendicular polarized emissions from probe molecules are acquired simultaneously, provide direct measurement of molecular rotational dynamics. In our experiments, the fluorescence from rhodamine 6G dye in various materials under GPa shocks produced by laser-driven flyer plates is collected, separated into two orthogonally-polarized beams using a Wollaston prism and detected with a streak camera. In liquids, the molecular rotations result from rotational diffusion and in solids from shear flow. The rotation rates can be used to determine the viscosity of the shocked medium.

  9. Probing the Intergalactic Magnetic Field with the Anisotropy of the Extragalactic Gamma-Ray Background

    NASA Technical Reports Server (NTRS)

    Venters, T. M.; Pavlidou, V.

    2012-01-01

    The intergalactic magnetic field (IGMF) may leave an imprint on the anisotropy properties of the extragalactic gamma-ray background, through its effect on electromagnetic cascades triggered by interactions between very high energy photons and the extragalactic background light. A strong IGMF will deflect secondary particles produced in these cascades and will thus tend to isotropize lower energy cascade photons, thus inducing a modulation in the anisotropy energy spectrum of the gamma-ray background. Here we present a simple, proof-of-concept calculation of the magnitude of this effect and demonstrate that the two extreme cases (zero IGMF and IGMF strong enough to completely isotropize cascade photons) would be separable by ten years of Fermi observations and reasonable model parameters for the gamma-ray background. The anisotropy energy spectrum of the Fermi gamma-ray background could thus be used as a probe of the IGMF strength.

  10. Probing the Intergalactic Magnetic Field with the Anisotropy of the Extragalactic Gamma-ray Background

    NASA Technical Reports Server (NTRS)

    Venters, T. M.; Pavlidou, V.

    2013-01-01

    The intergalactic magnetic field (IGMF) may leave an imprint on the angular anisotropy of the extragalactic gamma-ray background through its effect on electromagnetic cascades triggered by interactions between very high energy photons and the extragalactic background light. A strong IGMF will deflect secondary particles produced in these cascades and will thus tend to isotropize lower energy cascade photons, thereby inducing a modulation in the anisotropy energy spectrum of the gamma-ray background. Here we present a simple, proof-of-concept calculation of the magnitude of this effect and demonstrate that current Fermi data already seem to prefer nonnegligible IGMF values. The anisotropy energy spectrum of the Fermi gamma-ray background could thus be used as a probe of the IGMF strength.

  11. Discriminating neurogenic from myopathic disease via measurement of muscle anisotropy.

    PubMed

    Garmirian, Lindsay P; Chin, Anne B; Rutkove, Seward B

    2009-01-01

    Skeletal muscle is electrically anisotropic, with a tendency for applied electrical current to flow more readily along muscle fibers than across them. In this study, we assessed a method for non-invasive measurement of anisotropy to determine its potential to serve as a new technique for distinguishing neurogenic from myopathic disease. Measurements were made on the biceps brachii and tibialis anterior muscles in 15 normal subjects and 12 patients with neuromuscular disease (6 with amyotrophic lateral sclerosis and 6 with various myopathies) using 50 kHZ applied current. Consistent multi-angle anisotropic patterns were found for reactance and phase in both muscles in normal subjects. Normalized anisotropy differences for each subject were defined, and group average values identified. The amyotrophic lateral sclerosis (ALS) patients demonstrated increased and distorted anisotropy patterns, whereas myopathic patients demonstrated normal or reduced anisotropy. These results suggest that non-invasive measurement of muscle anisotropy has potential for diagnosis of neuromuscular diseases. PMID:19058193

  12. Gamma Astrometric Measurement Experiment

    NASA Astrophysics Data System (ADS)

    Gai, M.; Lattanzi, M. G.; Ligori, S.; Loreggia, D.; Vecchiato, A.

    GAME aims at the measurement of gravitational deflection of the light by the Sun, by an optimised telescope on board a small class satellite. The targeted precision on the gamma parameter of the Parametrised Post-Newtonian formulation of General Relativity is below 10-6, i.e. one to two orders of magnitude better than the best current results. Such precision is suitable to detect possible deviations from the unity value, associated to generalised Einstein models for gravitation, with potentially huge impacts on the cosmological distribution of dark matter and dark energy. The measurement principle is based on differential astrometry. The observations also allow additional scientific objectives related to tests of General Relativity and to the study of exo-planetary systems. The instrument concept is based on a dual field, multiple aperture Fizeau interferometer, observing simultaneously two regions close to the Solar limb. The diluted optics achieves efficient rejection of the solar radiation, with good angular resolution on the science targets. We describe the science motivation, the proposed mission implementation and the expected performance.

  13. Mechanical anisotropy in sheets of {gamma}-TiAl alloys

    SciTech Connect

    Bartels, A.; Hartig, C.; Mecking, H.; Clemens, H.

    1997-12-31

    At room temperature sheets of {gamma}-TiAl exhibit a higher yield stress in the rolling direction than in the transverse direction. Around 700 C the opposite behavior is observed. The texture mainly consists of a modified cube component. The tetragonal c-axis <001> is aligned in the sheet plane transversely to the rolling direction. Taken into account this special texture and the single crystal yield surface of {gamma}-TiAl the authors conclude that around 700 C the CRSS of super-dislocations is higher than the CRSS of ordinary dislocations. At RT the relation changes to the opposite.

  14. Viscous anisotropy of textured olivine aggregates, Part 1: Measurement of the magnitude and evolution of anisotropy

    NASA Astrophysics Data System (ADS)

    Hansen, Lars N.; Warren, Jessica M.; Zimmerman, Mark E.; Kohlstedt, David L.

    2016-07-01

    The development of crystallographic textures in olivine-rich rocks leads to a marked anisotropy in viscosity of the upper mantle, strongly influencing a variety of large-scale geodynamic processes. Most estimates of the magnitude of viscous anisotropy in the upper mantle are derived from micromechanical models that predict textural and mechanical evolution numerically. Unfortunately, relatively few data exist with which to benchmark these models, and therefore their applicability to geodynamic processes remains in question. Here we present the results from a series of laboratory deformation experiments that yield insight into the magnitude and evolution of the anisotropy of olivine aggregates during deformation along complex loading paths. Aggregates of Fo50 olivine were first deformed in extension in a gas-medium apparatus at a temperature of 1473 K, confining pressure of 300 MPa, and a variety of stresses and strain rates. Early in the extension experiments, samples exhibited viscosities similar to those previously determined for isotropic aggregates. Extensional deformation was accompanied by formation of crystallographic textures with [100] axes dominantly aligned with the extension axis. Samples were subsequently deformed in torsion under similar conditions to shear strains of up to 15.5. Early in the torsion experiments, samples supported stresses a factor of ∼2 larger than measured at the end of extension experiments, demonstrating a marked anisotropy in viscosity. Textures at the end of torsion experiments exhibited [100] axes dominantly aligned with the shear direction, comparable to previous experimental observations. Evolution of the textures resulting from extension to those resulting from torsion was analyzed through examination of radial sections of torsion samples. Our results confirm that texture produces viscous anisotropy in olivine aggregates, and we provide a simple, calibrated parameterization of viscous anisotropy for use in geodynamic

  15. Degree Scale Anisotropy Measurements of the Cosmic Microwave Background

    NASA Astrophysics Data System (ADS)

    Gundersen, Joshua Ott

    1995-01-01

    Humans have inquired about the origin, evolution, and content of the Universe for as long as history has been recorded. These paths of inquiry have only just recently evolved from the realm of philosophy and metaphysics into the very quantitative and predictive science of cosmology. This transition has been facilitated by the wealth of observational data in the last three decades. Although we have made large strides in our understanding of the Universe, there are many outstanding questions that have not been precisely answered. Some of these include, "How old is the Universe?", "What is the matter/energy content of the Universe?", Will the Universe continue to expand, or will it one day begin to collapse?", "How did the large scale structures (such as galaxies and clusters of galaxies) first form?". Over the past six years, detailed observations of the cosmic microwave background (CMB) have begun to constrain cosmological models which address these very questions. In particular, measurements of the spatial distribution (anisotropy) of the CMB have been shown to be very powerful tests of theories that attempt to explain the origin, evolution, contents and geometry of the Universe. The subject of this thesis is the search and characterization of medium angular scale anisotropy in the CMB. The scientific motivation for observing CMB anisotropy is presented within a general introduction to our current understanding of the Universe. An overview of the technological and observational hurdles that make CMB anisotropy measurements difficult is given. The main body of the text describes two experimental efforts to measure CMB anisotropy on medium angular scales. The first of these efforts is the Millimeter-wave Anisotropy eXperiment (MAX) which is a balloon-borne telescope that has been developed to measure CMB anisotropy. The second of these efforts involves ground-based observations of CMB anisotropy from the Amundsen-Scott South Pole station. Both of these efforts have

  16. SIMULTANEOUS MEASUREMENT OF CIRCULAR DICHROISM AND FLUORESCENCE POLARIZATION ANISOTROPY.

    SciTech Connect

    SUTHERLAND,J.C.

    2002-01-19

    Circular dichroism and fluorescence polarization anisotropy are important tools for characterizing biomolecular systems. Both are used extensively in kinetic experiments involving stopped- or continuous flow systems as well as titrations and steady-state spectroscopy. This paper presents the theory for determining circular dichroism and fluorescence polarization anisotropy simultaneously, thus insuring the two parameters are recorded under exactly the same conditions and at exactly the same time in kinetic experiments. The approach to measuring circular dichroism is that used in almost all conventional dichrographs. Two arrangements for measuring fluorescence polarization anisotropy are described. One uses a single fluorescence detector and signal processing with a lock-in amplifier that is similar to the measurement of circular dichroism. The second approach uses classic ''T'' format detection optics, and thus can be used with conventional photon-counting detection electronics. Simple extensions permit the simultaneous measurement of the absorption and excitation intensity corrected fluorescence intensity.

  17. Anisotropies in the diffuse gamma-ray background from dark matter with Fermi LAT: a closer look

    NASA Astrophysics Data System (ADS)

    Cuoco, A.; Sellerholm, A.; Conrad, J.; Hannestad, S.

    2011-07-01

    We perform a detailed study of the sensitivity to the anisotropies related to dark matter (DM) annihilation in the isotropic gamma-ray background (IGRB) as measured by the Fermi Large Area Telescope (Fermi LAT). For the first time, we take into account the effects of the Galactic foregrounds and use a realistic representation of the Fermi LAT. We implement an analysis pipeline which simulates Fermi LAT data sets starting from model maps of the Galactic foregrounds, the Fermi-resolved point sources, the extragalactic diffuse emission and the signal from DM annihilation. The effects of the detector are taken into account by convolving the model maps with the Fermi LAT instrumental response. We then use the angular power spectrum to characterize the anisotropy properties of the simulated data and to study the sensitivity to DM. We consider DM anisotropies of extragalactic origin and of Galactic origin (which can be generated through annihilation in the Milky Way substructures) as opposed to a background of anisotropies generated by sources of astrophysical origin, blazars for example. We find that with statistics from 5 yr of observation, Fermi is sensitive to a DM contribution at the level of 1-10 per cent of the measured IGRB depending on the DM mass mχ and annihilation mode. In terms of the thermally averaged cross-section <σAv>, this corresponds to ˜10-25 cm3 s-1, i.e. slightly above the typical expectations for a thermal relic, for low values of the DM mass mχ≲ 100 GeV. The anisotropy method for DM searches has a sensitivity comparable to the usual methods based only on the energy spectrum and thus constitutes an independent and complementary piece of information in the DM puzzle.

  18. Anisotropy measurement of pyrolytic carbon layers of coated particles

    NASA Astrophysics Data System (ADS)

    Vesyolkin, Ju. A.; Ivanov, A. S.; Trushkina, T. V.

    2015-12-01

    Equipment at the National Research Center Kurchatov Institute intended for the anisotropy determination of pyrolytic carbon layers in coated particles (CPs) of the GT-MGR reactor is tested and calibrated. The dependence of the anisotropy coefficient on the size of the measurement region is investigated. The results of measuring the optical anisotropy factor (OPTAF) for an aluminum mirror, rutile crystal, and available CP samples with the known characteristics measured previously using ORNL equipment (United States) are presented. In addition, measurements of CP samples prepared at VNIINM are performed. A strong dependence of the data on the preparation quality of metallographic sections is found. Our investigations allow us to make the conclusion on the working capacity of the existing equipment for measuring the anisotropy of pyrolytic carbon CP coatings using the equipment at the Kurchatov Institute with the relative error of about 1%. It is shown that the elimination of the errors caused by the stochastic fluctuations in a measuring path by mathematical processing of the signal allows us to decrease the relative error of OPTAF measurements to ~0.3%.

  19. Anisotropy measurement of pyrolytic carbon layers of coated particles

    SciTech Connect

    Vesyolkin, Ju. A. Ivanov, A. S.; Trushkina, T. V.

    2015-12-15

    Equipment at the National Research Center Kurchatov Institute intended for the anisotropy determination of pyrolytic carbon layers in coated particles (CPs) of the GT-MGR reactor is tested and calibrated. The dependence of the anisotropy coefficient on the size of the measurement region is investigated. The results of measuring the optical anisotropy factor (OPTAF) for an aluminum mirror, rutile crystal, and available CP samples with the known characteristics measured previously using ORNL equipment (United States) are presented. In addition, measurements of CP samples prepared at VNIINM are performed. A strong dependence of the data on the preparation quality of metallographic sections is found. Our investigations allow us to make the conclusion on the working capacity of the existing equipment for measuring the anisotropy of pyrolytic carbon CP coatings using the equipment at the Kurchatov Institute with the relative error of about 1%. It is shown that the elimination of the errors caused by the stochastic fluctuations in a measuring path by mathematical processing of the signal allows us to decrease the relative error of OPTAF measurements to ∼0.3%.

  20. Measuring the Stellar Halo Velocity Anisotropy With 3D Kinematics

    NASA Astrophysics Data System (ADS)

    Cunningham, Emily C.; Deason, Alis J.; Guhathakurta, Puragra; Rockosi, Constance M.; van der Marel, Roeland P.; Sohn, S. Tony

    2016-08-01

    We present the first measurement of the anisotropy parameter β using 3D kinematic information outside of the solar neighborhood. Our sample consists of 13 Milky Way halo stars with measured proper motions and radial velocities in the line of sight of M31. Proper motions were measured using deep, multi-epoch HST imaging, and radial velocities were measured from Keck II/DEIMOS spectra. We measure β = -0.3-0.9 +0.4, which is consistent with isotropy, and inconsistent with measurements in the solar neighborhood. We suggest that this may be the kinematic signature of a relatively early, massive accretion event, or perhaps several such events.

  1. A laboratory goniometer system for measuring reflectance and emittance anisotropy.

    PubMed

    Roosjen, Peter P J; Clevers, Jan G P W; Bartholomeus, Harm M; Schaepman, Michael E; Schaepman-Strub, Gabriela; Jalink, Henk; van der Schoor, Rob; de Jong, Arjan

    2012-01-01

    In this paper, a laboratory goniometer system for performing multi-angular measurements under controlled illumination conditions is described. A commercially available robotic arm enables the acquisition of a large number of measurements over the full hemisphere within a short time span making it much faster than other goniometers. In addition, the presented set-up enables assessment of anisotropic reflectance and emittance behaviour of soils, leaves and small canopies. Mounting a spectrometer enables acquisition of either hemispherical measurements or measurements in the horizontal plane. Mounting a thermal camera allows directional observations of the thermal emittance. This paper also presents three showcases of these different measurement set-ups in order to illustrate its possibilities. Finally, suggestions for applying this instrument and for future research directions are given, including linking the measured reflectance anisotropy with physically-based anisotropy models on the one hand and combining them with field goniometry measurements for joint analysis with remote sensing data on the other hand. The speed and flexibility of the system offer a large added value to the existing pool of laboratory goniometers. PMID:23443402

  2. A Laboratory Goniometer System for Measuring Reflectance and Emittance Anisotropy

    PubMed Central

    Roosjen, Peter P. J.; Clevers, Jan G. P. W.; Bartholomeus, Harm M.; Schaepman, Michael E.; Schaepman-Strub, Gabriela; Jalink, Henk; van der Schoor, Rob; de Jong, Arjan

    2012-01-01

    In this paper, a laboratory goniometer system for performing multi-angular measurements under controlled illumination conditions is described. A commercially available robotic arm enables the acquisition of a large number of measurements over the full hemisphere within a short time span making it much faster than other goniometers. In addition, the presented set-up enables assessment of anisotropic reflectance and emittance behaviour of soils, leaves and small canopies. Mounting a spectrometer enables acquisition of either hemispherical measurements or measurements in the horizontal plane. Mounting a thermal camera allows directional observations of the thermal emittance. This paper also presents three showcases of these different measurement set-ups in order to illustrate its possibilities. Finally, suggestions for applying this instrument and for future research directions are given, including linking the measured reflectance anisotropy with physically-based anisotropy models on the one hand and combining them with field goniometry measurements for joint analysis with remote sensing data on the other hand. The speed and flexibility of the system offer a large added value to the existing pool of laboratory goniometers. PMID:23443402

  3. Noninvasive measurement of conductivity anisotropy at larmor frequency using MRI.

    PubMed

    Lee, Joonsung; Song, Yizhuang; Choi, Narae; Cho, Sungmin; Seo, Jin Keun; Kim, Dong-Hyun

    2013-01-01

    Anisotropic electrical properties can be found in biological tissues such as muscles and nerves. Conductivity tensor is a simplified model to express the effective electrical anisotropic information and depends on the imaging resolution. The determination of the conductivity tensor should be based on Ohm's law. In other words, the measurement of partial information of current density and the electric fields should be made. Since the direct measurements of the electric field and the current density are difficult, we use MRI to measure their partial information such as B1 map; it measures circulating current density and circulating electric field. In this work, the ratio of the two circulating fields, termed circulating admittivity, is proposed as measures of the conductivity anisotropy at Larmor frequency. Given eigenvectors of the conductivity tensor, quantitative measurement of the eigenvalues can be achieved from circulating admittivity for special tissue models. Without eigenvectors, qualitative information of anisotropy still can be acquired from circulating admittivity. The limitation of the circulating admittivity is that at least two components of the magnetic fields should be measured to capture anisotropic information. PMID:23554838

  4. Maser radiometer for cosmic background radiation anisotropy measurements

    NASA Astrophysics Data System (ADS)

    Fixsen, D. J.; Wilkinson, D. T.

    1982-06-01

    A maser amplifier was incorporated into a low noise radiometer designed to measure large-scale anisotropy in the 3 deg K microwave background radiation. To minimize emission by atmospheric water vapor and oxygen, the radiometer is flown in a small balloon to an altitude to 25 km. Three successful flights were made - two from Palestine, Texas and one from Sao Jose dos Campos, Brazil. Good sky coverage is important to the experiment. Data from the northern hemisphere flights has been edited and calibrated.

  5. Maser radiometer for cosmic background radiation anisotropy measurements

    NASA Technical Reports Server (NTRS)

    Fixsen, D. J.; Wilkinson, D. T.

    1982-01-01

    A maser amplifier was incorporated into a low noise radiometer designed to measure large-scale anisotropy in the 3 deg K microwave background radiation. To minimize emission by atmospheric water vapor and oxygen, the radiometer is flown in a small balloon to an altitude to 25 km. Three successful flights were made - two from Palestine, Texas and one from Sao Jose dos Campos, Brazil. Good sky coverage is important to the experiment. Data from the northern hemisphere flights has been edited and calibrated.

  6. Simultaneous Measurement of Elastic and Electrical Anisotropy of Shales under Elevated Pressure: A Preliminary Study

    NASA Astrophysics Data System (ADS)

    Ou, L.; Niu, Q.; Prasad, M.

    2015-12-01

    Low-porosity shales are generally considered as transverse isotropic (TI) material, both elastically and electrically. We explore the correlation of elastic and electrical anisotropy of shales to mineralogy and organic richness. Both, elastic and electrical anisotropies in rocks are known to be functions of clay and kerogen contents. The elastic anisotropy in clay- and organic-rich shales is related to their laminated and lenticular texture that is enhanced with compaction and diagenesis leading. The correlation of complex resistivity and anisotropy in shales with clay content has theoretically modeled using cation exchange capacity of the clay minerals. Although, it is appear likely that elastic and electrical anisotropy might be controlled by similar petrophyiscal properties, very little research exists that explores the relationship between these two anisotropies and how petrophysical properties might influence them. We present an experimental data of elastic and electrical anisotropy in shales acquired with a new system that allows simultaneous measurements of acoustic velocities and complex resistivities under hydrostatic pressure in three directions: parallel, 45° and perpendicular to any orientation, such as bedding planes. Our results of five shale samples show: Elastic and electrical anisotropy are inversely related to pressure Electrical anisotropy is generally higher than elastic anisotropy Electrical anisotropy is more sensitive to pressure change Complex resistivity anisotropy for in-phase resistivity and phase is highly frequency dependent In future, we plan to measure shale samples with varying clay and organic contents and correlate anisotropy to petrophysical properties.

  7. Measurements of scattering anisotropy in dental tissue and zirconia ceramic

    NASA Astrophysics Data System (ADS)

    Fernández-Oliveras, Alicia; Pecho, Oscar E.; Rubiño, Manuel; Pérez, María M.

    2012-06-01

    Knowledge of the optical properties of biological structures is useful for clinical applications, especially when dealing with incoming biomaterials engineered to improve the benefits for the patient. One ceramic material currently used in restorative dentistry is yttrium cation-doped tetragonal zirconia polycrystal (3Y-TZP) because of its good mechanical properties. However, its optical properties have not been thoroughly studied. Many methods for the determination of optical parameters from biological media make the assumption that scattered light is isotropically distributed over all angles. Nevertheless, real biological materials may have an angular dependence on light scattering, which may affect the optical behaviour of the materials. Therefore, the recovery of the degree of anisotropy in the scattering angular distribution is important. The phase function that represents the scattering angular distribution is usually characterized by the anisotropy coefficient g, which equals the average cosine of the scattering angle. In this work, we measured angularscattering distributions for two zirconia ceramic samples, pre-sintered and sintered, with similar thicknesses (0.48 mm and 0.50 mm, respectively) and also for a human dentine sample (0.41 mm in thickness). The samples were irradiated with a He-Ne laser beam (λ = 632.8 nm) and the angular-scattering distributions were measured using a rotating goniometer. The g values yielded were: -0.7970 +/- 0.0016 for pre-sintered zirconia, -0.2074 +/- 0.0024 for sintered zirconia and 0.0620 +/- 0.0010 for dentine. The results show that zirconia sintering results in optical behaviour more similar to those of dentine tissue, in terms of scattering anisotropy.

  8. Scattering Anisotropy Measurements in Dental Tissues and Biomaterials

    NASA Astrophysics Data System (ADS)

    Fernandez-Oliveras, A.; Rubiño, M.; Perez, M. M.

    2012-05-01

    Understanding the behaviour of light propagation in biological materials is essential for biomedical engineering and applications, and even more so when dealing with incoming biomaterials. Many methods for determining optical parameters from biological media assume that scattered light is isotropically distributed over all angles. However, an angular dependence of light scattering may exist and affect the optical behaviour of biological media. The present work seeks to experimentally analyze the scattering anisotropy in different dental tissues (enamel and dentine) and their potential substitute biomaterials (hybrid dental-resin, nano-filled composite, and zirconia ceramic) and comparatively study them. Goniometric measurements were made for four wavelengths in the visible range, allowing a spectral characterization of the materials studied. Previously, for each material, measurements were made with two different sample thicknesses at the same wavelength, checking the behaviour of the angular scattering profile. The asymmetry of experimental phase functions was considered in the recovery of the scattering anisotropy factor. The results demonstrate that the thicker sample yielded a less forward-directed scattering profile than did the thinner sample. The biomaterials analysed show angular scattering comparable to those of the tissues that they may replace. Comparisons can be made by virtue of the low uncertainties found.

  9. Measurement of the gamma gamma* --> eta and gamma gamma* --> eta' transition form factors

    SciTech Connect

    del Amo Sanchez et al, P.

    2011-02-07

    We study the reactions e{sup +}e{sup -} {yields} e{sup +}e{sup -} {eta}{sup (/)} in the single-tag mode and measure the {gamma}{gamma}* {yields} {eta}{sup (/)} transition form factors in the momentum transfer range from 4 to 40 GeV{sup 2}. The analysis is based on 469 fb{sup -1} of integrated luminosity collected at PEP-II with the BABAR detector at e{sup +}e{sup -} center-of-mass energies near 10.6 GeV.

  10. Probing the Cosmic X-Ray and MeV Gamma-Ray Background Radiation through the Anisotropy

    SciTech Connect

    Inoue, Yoshiyuki; Murase, Kohta; Madejski, Grzegorz M.; Uchiyama, Yasunobu

    2013-09-24

    While the cosmic soft X-ray background is very likely to originate from individual Seyfert galaxies, the origin of the cosmic hard X-ray and MeV gamma-ray background is not fully understood. It is expected that Seyferts including Compton thick population may explain the cosmic hard X-ray background. At MeV energy range, Seyferts having non-thermal electrons in coronae above accretion disks or MeV blazars may explain the background radiation. We propose that future measurements of the angular power spectra of anisotropy of the cosmic X-ray and MeV gamma-ray backgrounds will be key to deciphering these backgrounds and the evolution of active galactic nuclei (AGNs). As AGNs trace the cosmic large-scale structure, spatial clustering of AGNs exists. We show that e-ROSITA will clearly detect the correlation signal of unresolved Seyferts at 0.5-2 keV and 2-10 keV bands and will be able to measure the bias parameter of AGNs at both bands. Once the future hard X-ray all sky satellites achieve the sensitivity better than 10-12 erg/cm2/s-1 at 10-30 keV or 30-50 keV - although this is beyond the sensitivities of current hard X-ray all sky monitors - angular power spectra will allow us to independently investigate the fraction of Compton-thick AGNs in all Seyferts. We also find that the expected angular power spectra of Seyferts and blazars in the MeV range are different by about an order of magnitude, where the Poisson term, so-called shot noise, is dominant. Current and future MeV instruments will clearly disentangle the origin of the MeV gamma-ray background through the angular power spectrum.

  11. Improved Tests of Special Relativity via Light Speed Anisotropy Measurement

    NASA Astrophysics Data System (ADS)

    Sfarti, A.

    The Mansouri-Sexl theory is a well-known test theory of relativity. In the following paper we demonstrate a novel way of detecting second-order effects in terms of both lab and ion speed for light speed anisotropy detection. Prior literature15,18-21 has shown the way of constraining the Mansouri-Sexl parameter "a" via the Ives-Stilwell experiment, however, the prior approaches have proven to be incomplete in managing to constrain only one parameter, the "a" parameter. In the current paper we will take the unprecedented step of reconstructing the Mansouri-Sexl formalism for the Ives-Stilwell experiment and by showing how to improve on the theoretical and experimental bases such as to constrain both the parameter "a" and the parameter "b". Our paper is organized as follows: in the first section we give a new and more complete derivation of the Mansouri-Sexl Doppler effect. In the second part, we apply the newly expanded Mansouri-Sexl Doppler formalism in order to revise the principles of the Ives-Stilwell experiment. We continue by showing how the revised experiment is to be used in order to constrain both the parameter "a" and the parameter "b" in a measurement of light speed isotropy. This turns the Mansouri-Sexl Ives-Stilwell experiment into a very powerful tool for constraining light speed anisotropy.

  12. What does anisotropy measure? Insights from increased and decreased anisotropy in selective fiber tracts in schizophrenia

    PubMed Central

    Alba-Ferrara, L. M.; de Erausquin, Gabriel A.

    2012-01-01

    Schizophrenia is a common, severe, and chronically disabling mental illness of unknown cause. Recent MRI studies have focused attention on white matter abnormalities in schizophrenia using diffusion tensor imaging (DTI). Indices commonly derived from DTI include (1) mean diffusivity, independent of direction, (2) fractional anisotropy (FA) or relative anisotropy (RA), (3) axial diffusivity, and (4) radial diffusivity. In cerebral white matter, contributions to these indices come from fiber arrangements, degree of myelination, and axonal integrity. Relatively pure deficits in myelin result in a modest increase in radial diffusivity, without affecting axial diffusivity and with preservation of anisotropy. Although schizophrenia is not characterized by gross abnormalities of white matter, it does involve a profound dysregulation of myelin-associated gene expression, reductions in oligodendrocyte numbers, and marked abnormalities in the ultrastructure of myelin sheaths. Since each oligodendrocyte myelinates as many as 40 axon segments, changes in the number of oligodendrocytes (OLG), and/or in the integrity of myelin sheaths, and/or axoglial contacts can have a profound impact on signal propagation and the integrity of neuronal circuits. Whereas a number of studies have revealed inconsistent decreases in anisotropy in schizophrenia, we and others have found increased FA in key subcortical tracts associated with the circuits underlying symptom generation in schizophrenia. We review data revealing increased anisotropy in dopaminergic tracts in the mesencephalon of schizophrenics and their unaffected relatives, and discuss the possible biological underpinnings and physiological significance of this finding. PMID:23483798

  13. Primordial gravitational waves measurements and anisotropies of CMB polarization rotation

    NASA Astrophysics Data System (ADS)

    Li, Si-Yu; Xia, Jun-Qing; Li, Mingzhe; Li, Hong; Zhang, Xinmin

    2015-12-01

    Searching for the signal of primordial gravitational waves in the B-modes (BB) power spectrum is one of the key scientific aims of the cosmic microwave background (CMB) polarization experiments. However, this could be easily contaminated by several foreground issues, such as the interstellar dust grains and the galactic cyclotron electrons. In this paper we study another mechanism, the cosmic birefringence, which can be introduced by a CPT-violating interaction between CMB photons and an external scalar field. Such kind of interaction could give rise to the rotation of the linear polarization state of CMB photons, and consequently induce the CMB BB power spectrum, which could mimic the signal of primordial gravitational waves at large scales. With the recently released polarization data of BICEP2 and the joint analysis data of BICEP2/Keck Array and Planck, we perform a global fitting analysis on constraining the tensor-to-scalar ratio r by considering the polarization rotation angle [ α (n ˆ)] which can be separated into a background isotropic part [ α bar ] and a small anisotropic part [ Δα (n ˆ)]. Since the data of BICEP2 and Keck Array experiments have already been corrected by using the "self-calibration" method, here we mainly focus on the effects from the anisotropies of CMB polarization rotation angle. We find that including Δα (n ˆ) in the analysis could slightly weaken the constraints on the tensor-to-scalar ratio r, when using current CMB polarization measurements. We also simulate the mock CMB data with the BICEP3-like sensitivity. Very interestingly, we find that if the effects of the anisotropic polarization rotation angle could not be taken into account properly in the analysis, the constraints on r will be dramatically biased. This implies that we need to break the degeneracy between the anisotropies of the CMB polarization rotation angle and the CMB primordial tensor perturbations, in order to measure the signal of primordial gravitational

  14. Measurements of Gamma in BaBar

    SciTech Connect

    Marchiori, G.; /INFN, Pisa

    2006-08-30

    We report on the first measurements to the angle {gamma} of the Unitarity Triangle in B meson decays collected by the BABAR detector at the SLAC PEP-II asymmetric-energy B factory in the years 1999-2004.

  15. The sensitivity of Cherenkov telescopes to dark matter and astrophysical anisotropies in the diffuse gamma-ray background

    SciTech Connect

    Ripken, Joachim; Cuoco, Alessandro; Conrad, Jan; Zechlin, Hannes-S.; Horns, Dieter E-mail: cuoco@fysik.su.se E-mail: conrad@fysik.su.se

    2014-01-01

    In this article, the capability of present (H.E.S.S., MAGIC, VERITAS) and planned (CTA) ground-based Cherenkov telescope systems for detecting angular anisotropies in the diffuse gamma-ray background is investigated. Following up on a study of the impact of instrumental characteristics (effective area, field of view, angular resolution, and background rejection efficiency), the first part examines the influence of different observational strategies, i.e. whether a single deep observation or a splitting over multiple shallow fields is preferred. In the second part, the sensitivity to anisotropies generated by self-annihilating dark matter is studied for different common dark matter models. We find that a relative contribution of ∼ 10% from dark matter annihilation to the extra-galactic diffuse gamma-ray background can be detected with planned configurations of CTA. In terms of the thermally-averaged self-annihilation cross section, the sensitivity of CTA corresponds to values below the thermal freeze-out expectation (σv) = 3 × 10{sup −26} cm{sup 3} s{sup −1} for dark matter particles lighter than ∼ 200 GeV. We stress the importance of constraining anisotropies from unresolved astrophysical sources with currently operating instruments already, as a novel and complementary method for investigating the properties of TeV sources.

  16. Measurement of the gamma gamma* -> pi0 transition form factor

    SciTech Connect

    Aubert, B.

    2009-06-02

    We study the reaction e{sup +}e{sup -} {yields} e{sup +}e{sup -}{pi}{sup 0} in the single tag mode and measure the differential cross section d{sigma}/dQ{sup 2} and the {gamma}{gamma}* {yields} {pi}{sup 0} transition form factor in the mometum transfer range from 4 to 40 GeV{sup 2}. At Q{sup 2} > 10 GeV{sup 2} the measured form factor exceeds the asymptotic limit predicted by perturbative QCD. The analysis is based on 442 fb{sup -1} of integrated luminosity collected at PEP-II with the BABAR detector at e{sup +}e{sup -} center-of-mass energies near 10.6 GeV.

  17. Airborne Spectral Measurements of Ocean Anisotropy during CLAMS

    NASA Technical Reports Server (NTRS)

    Gatebe, C. K.; King, M. D.; Arnold, G. T.; Lau, William K. M. (Technical Monitor)

    2002-01-01

    The Cloud Absorption Radiometer (CAR) aboard the University of Washington Convair CV-580 research aircraft obtained bidirectional reflectance-distribution function (BRDF) of Atlantic Ocean and Dismal Swamp between July 10 and August 2, 2001. The BRDF measurements (15 in total, 8 uncontaminated by clouds) obtained under a variety of sun angles and wind conditions, will be used to characterize ocean anisotropy in support of Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) science objectives principally to validate products from NASA's EOS satellites, and to parameterize and validate BRDF models of the ocean. In this paper we present results of BRDF of the Ocean under different sun angles and wind conditions. The CAR is capable of measuring scattered light in fourteen spectral bands. The scan mirror, rotating at 100 rpm, directs the light into a Dall-Kirkham telescope where the beam is split into nine paths. Eight light beams pass through beam splitters, dichroics, and lenses to individual detectors (0.34-1.27 micron), and finally are registered by eight data channels. They are sampled simultaneously and continuously. The ninth beam passes through a spinning filter wheel to an InSb detector cooled by a Stirling cycle cooler. Signals registered by the ninth data channel are selected from among six spectral channels (1.55-2.30 micron). The filter wheel can either cycle through all six spectral bands at a prescribed interval (usually changing filter every fifth scan line), or lock onto any one of the six spectral bands and sample it continuously. To measure the BRF of the surface-atmosphere system, the University of Washington CV-580 had to fly in a circle about 3 km in diameter above the surface for roughly two minutes. Replicated observations (multiple circular orbits) were acquired over selected surfaces so that average BRF smooth out small-scale surface and atmospheric inhomogeneities. At an altitude of 600 m above the targeted surface area and

  18. Measuring neutron yield and ρR anisotropies with activation foils at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Bleuel, D. L.; Bernstein, L. A.; Bionta, R. M.; Cooper, G. W.; Drury, O. B.; Hagmann, C. A.; Knittel, K. M.; Leeper, R. J.; Ruiz, C. L.; Schneider, D. H. G.; Yeamans, C. B.

    2013-11-01

    Neutron yields at the National Ignition Facility (NIF) are measured with a suite of diagnostics, including activation of ˜20-200 g samples of materials undergoing a variety of energy-dependent neutron reactions. Indium samples were mounted on the end of a Diagnostic Instrument Manipulator (DIM), 25-50 cm from the implosion, to measure 2.45 MeV D-D fusion neutron yield. The 336.2 keV gamma rays from the 4.5 hour isomer of 115mIn produced by (n,n') reactions are counted in high-purity germanium detectors. For capsules producing D-T fusion reactions, zirconium and copper are activated via (n,2n) reactions at various locations around the target chamber and bay, measuring the 14 MeV neutron yield to accuracies on order of 7%. By mounting zirconium samples on ports at nine locations around the NIF chamber, anisotropies in the primary neutron emission due to fuel areal density asymmetries can be measured to a relative precision of 3%.

  19. A comparative study of magnetic anisotropy measurement techniques in relation to rock-magnetic properties

    NASA Astrophysics Data System (ADS)

    Bilardello, Dario; Jackson, Michael J.

    2014-08-01

    Magnetic anisotropy measurements are becoming increasingly common to many studies within the different disciplines of geology, involving sedimentary, igneous and metamorphic rocks. A plethora of techniques exists for measuring magnetic anisotropy of rocks. Some are rapid and non-destructive while others are more labor-intensive or may result in alteration of the magnetic minerals. All, however, have the potential of revealing a wealth of information when measured and interpreted correctly. In broad terms, anisotropy techniques subdivide into measurements of susceptibility, remanence and torque; here we consider the first two of these. Anisotropy of magnetic susceptibility (AMS) is by far the most utilized, and measures composite fabrics. Magnetic susceptibilities in high fields and low temperatures, however, are being increasingly used to isolate the paramagnetic contribution to the fabrics. When distinguishing between fabrics carried by different ferromagnetic phases, or to separate these from the diamagnetic and paramagnetic contributions to the fabric, then remanence anisotropy techniques become necessary. Anisotropies of thermal remanence (ATRMs), of anhysteretic remanence (AARM) and of isothermal remanence (AIRM) are the most common examples. Remanence anisotropy may be measured over the full spectrum of magnetic coercivities or over a targeted range (e.g. partial or ApARM). Moreover, anisotropies may be calculated using only the resolved field-parallel component of the vector, in which case a minimum of six different orientations is necessary to obtain a complete symmetric tensor, or using the three components (full vector) of the measured magnetic vectors (e.g. AvARM), in which case three orthogonal applied magnetizations are the minimum requirement. In this study we utilize a variety of magnetic remanence room temperature techniques to measure remanence anisotropy of selected coarse and finer grained gneiss-granulitic specimens with well-pronounced fabrics

  20. Measurement of the magnetic anisotropy energy constants for magneto-optical recording media

    NASA Technical Reports Server (NTRS)

    Hajjar, R. A.; Wu, T. H.; Mansuripur, M.

    1992-01-01

    Measurement of the magneto-optical polar Kerr effect is performed on rare earth-transition metal (RE-TM) amorphous films using in-plane fields. From this measurement and the measurement of the saturation magnetization using a vibrating sample magnetometer (VSM), the magnetic anisotropy constants are determined. The temperature dependence is presented of the magnetic anisotropy in the range of -175 to 175 C. The results show a dip in the anisotropy near magnetic compensation. This anomaly is explained based on the finite exchange coupling between the rare earth and transition metal subnetworks.

  1. Angular Anisotropies in the Cosmic Gamma-Ray Background as a Probe of Its Origin

    NASA Astrophysics Data System (ADS)

    Miniati, Francesco; Koushiappas, Savvas M.; Di Matteo, Tiziana

    2007-09-01

    Notwithstanding the advent of the Gamma-ray Large Area Space Telescope, theoretical models predict that a significant fraction of the cosmic γ-ray background (CGB), at a level of 20% of the currently measured value, will remain unresolved. The angular power spectrum of intensity fluctuations of the CGB contains information on its origin. We show that probing the latter on scales from a few tens of arcminutes to several degrees, together with complementary GLAST observations of γ-ray emission from galaxy clusters and the blazar luminosity function, can discriminate between a background that originates from unresolved blazars or cosmic rays accelerated at structure formation shocks.

  2. FIELD EVALUATION OF DIPOLE METHOD TO MEASURE AQUIFER ANISOTROPY

    EPA Science Inventory

    The ultimate size of a three-dimensional groundwater circulation cell surrounding a vertical circulation well (VCW) is a strong function of the aquifer hydraulic anisotropy, the ratio of the hydraulic conductivity in the horizontal direction to that in the vertical direction. In ...

  3. Lower limits on the anisotropy of the extragalactic gamma-ray background implied by the 2FGL and 1FHL catalogs

    SciTech Connect

    Broderick, Avery E.; Smith, Kendrick M.; Pfrommer, Christoph; Puchwein, Ewald; Chang, Philip

    2014-11-20

    In principle, the angular anisotropy in the extragalactic gamma-ray background (EGRB) places severe constraints upon putative populations of unresolved gamma-ray point sources. Existing estimates of the EGRB anisotropy have been constructed by excising known point sources, e.g., taken from the First or Two Year Fermi-LAT Source Catalog (1FGL or 2FGL, respectively) and statistically analyzing the residual gamma-ray sky maps. We perform an independent check of the EGRB anisotropy limits by comparing the values obtained from the 1FGL-masked sky maps to the signal implied by sources that lie below the 1FGL detection threshold in the more sensitive 2FGL and 1FHL (First Fermi-LAT catalog of >10 GeV sources). As such, our analysis provides an internal consistency check of implications for source counts and spectral index distributions of gamma-ray bright active galactic nuclei obtained from Fermi-LAT data. Based on this, we find evidence for substantially larger anisotropies than those previously reported at energies above 5 GeV, where BL Lac objects are likely to provide the bulk of their contribution to the EGRB. This uncertainty in the EGRB anisotropy cautions against using it as an independent constraint for the high-redshift gamma-ray universe. Moreover, this would suggest that contrary to previous claims, smooth extensions of the resolved point-source population may be able to simultaneously explain both the isotropic and anisotropic components of the EGRB.

  4. Lower Limits on the Anisotropy of the Extragalactic Gamma-Ray Background Implied by the 2FGL and 1FHL Catalogs

    NASA Astrophysics Data System (ADS)

    Broderick, Avery E.; Pfrommer, Christoph; Puchwein, Ewald; Chang, Philip; Smith, Kendrick M.

    2014-11-01

    In principle, the angular anisotropy in the extragalactic gamma-ray background (EGRB) places severe constraints upon putative populations of unresolved gamma-ray point sources. Existing estimates of the EGRB anisotropy have been constructed by excising known point sources, e.g., taken from the First or Two Year Fermi-LAT Source Catalog (1FGL or 2FGL, respectively) and statistically analyzing the residual gamma-ray sky maps. We perform an independent check of the EGRB anisotropy limits by comparing the values obtained from the 1FGL-masked sky maps to the signal implied by sources that lie below the 1FGL detection threshold in the more sensitive 2FGL and 1FHL (First Fermi-LAT catalog of >10 GeV sources). As such, our analysis provides an internal consistency check of implications for source counts and spectral index distributions of gamma-ray bright active galactic nuclei obtained from Fermi-LAT data. Based on this, we find evidence for substantially larger anisotropies than those previously reported at energies above 5 GeV, where BL Lac objects are likely to provide the bulk of their contribution to the EGRB. This uncertainty in the EGRB anisotropy cautions against using it as an independent constraint for the high-redshift gamma-ray universe. Moreover, this would suggest that contrary to previous claims, smooth extensions of the resolved point-source population may be able to simultaneously explain both the isotropic and anisotropic components of the EGRB.

  5. Investigating the Anisotropic Scintillation Response in Anthracene through Neutron, Gamma-Ray, and Muon Measurements

    SciTech Connect

    Schuster, Patricia; Brubaker, Erik

    2016-01-01

    Our paper reports a series of measurements that characterize the directional dependence of the scintillation response of crystalline anthracene to incident DT neutrons, DD neutrons, 137Cs gamma rays, and, for the first time, cosmic ray muons. Moreover, the neutron measurements give the amplitude and pulse shape dependence on the proton recoil direction over one hemisphere of the crystal, confirming and extending previous results in the literature. In similar measurements using incident gamma rays, no directional effect is evident, and any anisotropy with respect to the electron recoil direction is constrained to have a magnitude of less than a tenth of that present in the proton recoil events. Cosmic muons are measured at two directions, and no anisotropy is observed. Our set of observations indicates that high dE/dx is necessary for an anisotropy to be present for a given type of scintillation event, which in turn could be used to discriminate among different hypotheses for the underlying causes of the anisotropy, which are not well understood.

  6. Investigating the anisotropic scintillation response in anthracene through neutron, gamma-ray, and muon measurements

    DOE PAGESBeta

    Schuster, Patricia; Brubaker, Erik

    2016-05-05

    Our paper reports a series of measurements that characterize the directional dependence of the scintillation response of crystalline anthracene to incident DT neutrons, DD neutrons, 137Cs gamma rays, and, for the first time, cosmic ray muons. Moreover, the neutron measurements give the amplitude and pulse shape dependence on the proton recoil direction over one hemisphere of the crystal, confirming and extending previous results in the literature. In similar measurements using incident gamma rays, no directional effect is evident, and any anisotropy with respect to the electron recoil direction is constrained to have a magnitude of less than a tenth ofmore » that present in the proton recoil events. Cosmic muons are measured at two directions, and no anisotropy is observed. Our set of observations indicates that high dE/dx is necessary for an anisotropy to be present for a given type of scintillation event, which in turn could be used to discriminate among different hypotheses for the underlying causes of the anisotropy, which are not well understood.« less

  7. Neutron and Gamma-ray Measurements

    NASA Astrophysics Data System (ADS)

    Krasilnikov, Anatoly V.; Sasao, Mamiko; Kaschuck, Yuri A.; Kiptily, Vasily G.; Nishitani, Takeo; Popovichev, Sergey V.; Bertalot, Luciano

    2008-03-01

    Due to high neutron and gamma-ray yields and large size plasmas many future fusion reactor plasma parameters such as fusion power, fusion power density, ion temperature, fuel mixture, fast ion energy and spatial distributions can be well measured by various fusion product diagnostics. Neutron diagnostics provide information on fusion reaction rate, which indicates how close is the plasma to the ultimate goal of nuclear fusion and fusion power distribution in the plasma core, which is crucial for optimization of plasma breakeven and burn. Depending on the plasma conditions neutron and gamma-ray diagnostics can provide important information, namely about dynamics of fast ion energy and spatial distributions during neutral beam injection, ion cyclotron heating and generated by fast ions MHD instabilities. The influence of the fast particle population on the 2-D neutron source profile was clearly demonstrated in JET experiments. 2-D neutron and gamma-ray source measurements could be important for driven plasma heating profile optimization in fusion reactors. To meat the measurement requirements in ITER the planned set of neutron and gamma ray diagnostics includes radial and vertical neutron and gamma cameras, neutron flux monitors, neutron activation systems and neutron spectrometers. The necessity of using massive radiation shielding strongly influences the diagnostic designs in fusion reactor, determines angular fields of view of neutron and gamma-ray cameras and spectrometers and gives rise to unavoidable difficulties in the absolute calibration. The development, testing in existing tokomaks and a possible engineering integration of neuron and gamma-ray diagnostic systems into ITER are presented.

  8. Identification of crystalline elastic anisotropy in PZT ceramics from in-situ blocking stress measurements

    SciTech Connect

    Daniel, L.; Hall, D. A.; Withers, P. J.; Webber, K. G.; King, A.

    2014-05-07

    High energy x-ray diffraction measurements of lattice strains were performed on a rhombohedral Lead Zirconate Titanate ceramic (PZT 55-45) under combinations of applied electric field and compressive stress. These measurements allow the construction of blocking stress curves for different sets of crystallographic orientations which reflect the single crystal elastic anisotropy. A micro-mechanical interpretation of the results is then proposed. Assuming cubic symmetry for the crystalline elastic stiffness tensor and isotropy for the macroscopic elastic properties, the elastic properties of the single crystal are extracted from the measured data. An anisotropy ratio close to 0.3 is found (compared to 1 for isotropic materials). The high level of anisotropy found in this work suggests that crystalline elastic anisotropy should not be neglected in the modelling of ferroelectric materials.

  9. Anisotropy of seasonal snow measured by polarimetric phase differences in radar time series

    NASA Astrophysics Data System (ADS)

    Leinss, S.; Löwe, H.; Proksch, M.; Lemmetyinen, J.; Wiesmann, A.; Hajnsek, I.

    2015-11-01

    Snow settles under the force of gravity and recrystallizes by vertical temperature gradients. Both effects are assumed to form oriented ice crystals which induce an anisotropy in mechanical, thermal, and dielectric properties of the snow pack. On microscopic scales, the anisotropy could be hitherto determined only from stereology or computer tomography of samples taken from snow pits. In this paper we present an alternative method and show how the anisotropy of a natural snow pack can be observed contact- and destruction-free with polarimetric radar measurements. The copolar phase differences (CPD) of polarized microwaves transmitted through dry snow were analyzed for four winter seasons (2009-2013) from the SnowScat Instrument, installed at a test site near the town of Sodankylä, Finnland. An electrodynamic model was established based on anisotropic optics and on Maxwell-Garnett-type mixing formulas to provide a link between the structural anisotropy and the measured CPD. The anisotropy values derived from the CPD were compared with in-situ anisotropy measurements obtained by computer tomography. In addition, we show that the CPD measurements obtained from SnowScat show the same temporal evolution as space-borne CPD measurements from the satellite TerraSAR-X. The presented dataset provides a valuable basis for the future development of snow models capable of including the anisotropic structure of snow.

  10. Mechanical anisotropy of a gamma titanium aluminide alloy after hot extrusion

    SciTech Connect

    Oehring, M.; Lorenz, U.; Niefanger, R.; Appel, F.; Brokmeier, H.G.; Wagner, R.; Clemens, H.; Eberhardt, N.

    1999-07-01

    By hot extrusion below and above the {alpha} transus temperature equiaxed and predominantly lamellar microstructures were obtained in a Ti aluminide alloy. In order to examine a possible orientation dependence of mechanical properties the flow stress, the activation parameters of plastic deformation and the fracture toughness were determined parallel and perpendicular to the extrusion direction at room temperature and 700 C. The observed anisotropy in these properties may be mainly attributed to anisotropies in the microstructures, in particular to a preferential alignment of lamellae in lamellar microstructures.

  11. Measuring remanence anisotropy of hematite in red beds: anisotropy of high-field isothermal remanence magnetization (hf-AIR)

    NASA Astrophysics Data System (ADS)

    Bilardello, Dario; Kodama, Kenneth P.

    2009-09-01

    The potential of using high-field anisotropy of isothermal remanence magnetization (hf-AIR) measurements for determining the origin of natural remanent magnetization in red beds and for identifying and correcting possible red-bed inclination shallowing was investigated for specimens of the Carboniferous Shepody Formation of New Brunswick and Nova Scotia, Canada. The technique makes it possible for a typical paleomagnetic laboratory to measure the remanence anisotropy of high-coercivity hematite. High-field (hf) AIR was used in conjunction with 100 mT alternating field (af) and 120°C thermal demagnetization to separate the contribution of hematite to the remanence anisotropy from that of magnetite/maghemite and goethite, respectively. A 5-T impulse DC magnetic field was used for the hf-AIR to reset the magnetic moment of high-coercivity hematite so that demagnetization between AIR orientations was not necessary. The ability of a 5-T field to reset the magnetization was tested by generating an isothermal remanent magnetization acquisition curve for hematite by using impulse DC magnetic fields up to 5 T in one orientation and followed by applying a field in the opposite direction at each step. Each field application was treated by 120°C heating and 100 mT af demagnetization before measurement. At 5 T, the difference between the magnetizations applied in opposite directions disappeared indicating that no magnetic memory persisted at this field strength. We performed a validity and reproducibility test of our hf-AIR measurement technique by measuring three specimens multiple times along two orthogonal coordinate systems. The method yielded highly reproducible results and, on rotating the specimen's coordinates, the fabric rotated by 90° as expected, showing that it is not an artifact of the technique. We also measured hf-AIR on samples that had previously been chemically demagnetized in 3N HCl to remove the secondary, chemically grown pigmentary hematite. The hf

  12. Gamma-ray multiplicity measurements using STEFF

    NASA Astrophysics Data System (ADS)

    Pollitt, A. J.; Smith, A. G.; Tsekhanovich, I.; Dare, J. A.

    2012-09-01

    An ongoing investigation into the angular momentum generated during the fission of 252Cf is currently under way using the SpecTrometer for Exotic Fission Fragments (STEFF). Measurements have been made of the fold distribution (measured multiplicity) with STEFF. These have been compared to a Monte-carlo simulation to determine a value for the average angular momentum Jrms = 6hslash which is comparable to previous measurements [1]. Measurements of the gamma-ray multiplicity were performed whilst gating on different fragment mass regions. The result was compared with a sum of the lowest 2+ energies from both fragment and complementary in the mass gate. The results support the view that gamma-ray multiplicity is largely determined by the decay of the nucleus through near yrast transitions that follow the statistical decay.

  13. In situ measurement of CuPt alloy ordering using strain anisotropy

    SciTech Connect

    France, Ryan M.; McMahon, William E.; Kang, Joongoo; Steiner, Myles A.; Geisz, John F.

    2014-02-07

    The optical and electrical properties of many III-V alloys change with the degree of CuPt atomic ordering, which is very sensitive to growth conditions. The bulk ordered alloy is elongated along the normal to the ordered planes, and is asymmetrically strained when coherent to a cubic substrate. Here, we demonstrate in situ measurement of the anisotropic strain due to ordering using two-dimensional wafer curvature. The measurement is sensitive to bulk anisotropies, and so is complementary to other in situ measurements that are sensitive to surface anisotropies. Using ab initio calculations, we determine a maximum strain anisotropy of 0.27% between [110] and [1{sup ¯}10] when perfectly ordered single-variant GaInP{sub 2} is coherent to a (001) cubic substrate. We relate the in situ measurement of strain anisotropy on various GaInP{sub 2} samples to ex situ measurements of the order parameter to validate the measurement and confirm the capability to predict material properties. The measurement monitors change in ordering during growth, useful for quickly determining the growth condition dependence of ordering or monitoring order-disorder transitions. More generally, this measurement technique could, in principle, be used to monitor phase changes in any epitaxial system for which the strain anisotropy of the two phases differs.

  14. Azimuthal anisotropy beneath southern Africa from very broad-band surface-wave dispersion measurements

    NASA Astrophysics Data System (ADS)

    Adam, Joanne M.-C.; Lebedev, Sergei

    2012-10-01

    Seismic anisotropy within the lithosphere of cratons preserves an important record of their ancient assembly. In southern Africa, anisotropy across the Archean Kaapvaal Craton and Limpopo Belt has been detected previously by observations of SKS-wave splitting. Because SKS-splitting measurements lack vertical resolution, however, the depth distribution of anisotropy has remained uncertain. End-member interpretations invoked the dominance of either anisotropy in the lithosphere (due to the fabric formed by deformation in Archean or Palaeoproterozoic orogenies) or that in the asthenosphere (due to the fabric formed by the recent plate motion), each with significant geodynamic implications. To determine the distribution of anisotropy with depth, we measured phase velocities of seismic surface waves between stations of the Southern African Seismic Experiment. We applied two complementary measurement approaches, very broad-band cross-correlation and multimode waveform inversion. Robust, Rayleigh- and Love-wave dispersion curves were derived for four different subregions of the Archean southern Africa in a period range from 5 s to 250-400 s (Rayleigh) and 5 s to 100-250 s (Love), depending on the region. Rayleigh-wave anisotropy was determined in each region at periods from 5 s to 150-200 s, sampling from the upper crust down to the asthenosphere. The jackknife method was used to estimate uncertainties, and the F-test to verify the statistical significance of anisotropy. We detected strong anisotropy with a N-S fast-propagation azimuth in the upper crust of the Limpopo Belt. We attribute it to aligned cracks, formed by the regional, E-W extensional stress associated with the southward propagation of the East African Rift. Our results show that it is possible to estimate regional stress from short-period, surface wave anisotropy, measured in this study using broad-band array recordings of teleseismic surface waves. Rayleigh-wave anisotropy at 70-120 s periods shows that

  15. Accidental gamma dose measurement using commercial glasses.

    PubMed

    Narayan, Pradeep; Vaijapurkar, S G; Senwar, K R; Kumar, D; Bhatnagar, P K

    2008-01-01

    Commercial glasses have been investigated for their application in accidental gamma dose measurement using Thermoluminescent (TL) techniques. Some of the glasses have been found to be sensitive enough that they can be used as TL dating material in radiological accident situation for gamma dosimetry with lower detection limit 1 Gy (the dose significant for the onset of deterministic biological effects). The glasses behave linearly in the dose range 1-25 Gy with measurement uncertainty +/- 10%. The errors in accidental dose measurements using TL technique are estimated to be within +/- 25%. These glasses have shown TL fading in the range of 10-20% in 24 h after irradiation under room conditions; thereafter the fading becomes slower and reaches upto 50% in 15 d. TL fading of gamma-irradiated glasses follows exponential decay pattern, therefore dosimetry even after years is possible. These types of glasses can also be used as lethal dose indicator (3-4 Gy) using TL techniques, which can give valuable inputs to the medical professional for better management of radiation victims. The glasses are easy to use and do not require lengthy sample preparation before reading as in case of other building materials. TL measurement on glasses may give immediate estimation of the doses, which can help in medical triage of the radiation-exposed public. PMID:18285317

  16. Reflectance Anisotropy Measurements Using a Pushbroom Spectrometer Mounted on Uav and a Laboratory Goniometer - Preliminary Results

    NASA Astrophysics Data System (ADS)

    Suomalainen, J.; Roosjen, P.; Bartholomeus, H.; Clevers, J.

    2015-08-01

    During 2014-2015 we have developed a new method to measure reflectance factor anisotropy using a pushbroom spectrometer mounted on a multicopter UAV. In this paper/presentation we describe the acquisition method and show the preliminary results of the experiment. To validate the measurements the same targets have also been measured with a laboratory goniometer system. The first experiments over sugar beet fields in 2014 show similar trends in both UAV and laboratory anisotropy data, but also some differences caused by differences in sampling and diffuse illumination. In 2015 a more extensive study on wheat, barley and potato fields were performed. The measurements were repeated on three days over the growth of the crops allowing linking the development of the crops to the anisotropy signals. On each day the anisotropy measurement was repeated 4-5 times with different solar zenith angles ranging from 60° to 40° allowing analysis how the solar angle affects the anisotropy. The first results of these experiments will be presented in this conference.

  17. Measures of three-dimensional anisotropy and intermittency in strong Alfvénic turbulence

    NASA Astrophysics Data System (ADS)

    Mallet, A.; Schekochihin, A. A.; Chandran, B. D. G.; Chen, C. H. K.; Horbury, T. S.; Wicks, R. T.; Greenan, C. C.

    2016-06-01

    We measure the local anisotropy of numerically simulated strong Alfvénic turbulence with respect to two local, physically relevant directions: along the local mean magnetic field and along the local direction of one of the fluctuating Elsasser fields. We find significant scaling anisotropy with respect to both these directions: the fluctuations are `ribbon-like' - statistically, they are elongated along both the mean magnetic field and the fluctuating field. The latter form of anisotropy is due to scale-dependent alignment of the fluctuating fields. The intermittent scalings of the nth-order conditional structure functions in the direction perpendicular to both the local mean field and the fluctuations agree well with the theory of Chandran, Schekochihin & Mallet, while the parallel scalings are consistent with those implied by the critical-balance conjecture. We quantify the relationship between the perpendicular scalings and those in the fluctuation and parallel directions, and find that the scaling exponent of the perpendicular anisotropy (i.e. of the aspect ratio of the Alfvénic structures in the plane perpendicular to the mean magnetic field) depends on the amplitude of the fluctuations. This is shown to be equivalent to the anticorrelation of fluctuation amplitude and alignment at each scale. The dependence of the anisotropy on amplitude is shown to be more significant for the anisotropy between the perpendicular and fluctuation-direction scales than it is between the perpendicular and parallel scales.

  18. Method and means for measuring the anisotropy of a plasma in a magnetic field

    DOEpatents

    Shohet, J.L.; Greene, D.G.S.

    1973-10-23

    Anisotropy is measured of a free-free-bremsstrahlungradiation-generating plasma in a magnetic field by collimating the free-free bremsstrahlung radiation in a direction normal to the magnetic field and scattering the collimated free- free bremsstrahlung radiation to resolve the radiation into its vector components in a plane parallel to the electric field of the bremsstrahlung radiation. The scattered vector components are counted at particular energy levels in a direction parallel to the magnetic field and also normal to the magnetic field of the plasma to provide a measure of anisotropy of the plasma. (Official Gazette)

  19. Measurement of thermal diffusivity, elastic anisotropy and crystallographic orientation by interferometric photothermal microscopy

    NASA Astrophysics Data System (ADS)

    Jumel, Julien; Rochais, Denis

    2007-07-01

    This paper describes the use of interferometric photothermal microscopy for measuring the thermal diffusivity, crystallographic orientation and elastic anisotropy of a microscopic homogeneous volume of matter. This purely optical technique makes use of an intensity-modulated and focused laser beam to periodically heat the surface of the sample tested. An interferometer is used to detect the thermal expansion. After describing the experimental setup, we explain the inversion scheme allowing the determination of the local thermal diffusivity from the periodic sample surface displacement map, as well as the crystallographic orientation and elastic anisotropy in the case of cubic materials. These parameters are measured with a spatial resolution of a few cubic micrometres.

  20. Direct measurement of hematite individual particle anisotropy: implications for inclination shallowing in red bed DRMs.

    NASA Astrophysics Data System (ADS)

    Bilardello, D.; Kodama, K. P.

    2007-12-01

    Methods to correct for the observed inclination shallowing in sedimentary rocks have been proposed that are based on either models of the geomagnetic field and the resulting directional distribution of paleomagnetic vectors or the magnetic anisotropy of the magnetic minerals carrying the remanence. One limitation of the anisotropy method for hematite-bearing red beds has been the isolation and determination of a rock's detrital hematite individual particle anisotropy. Up to now, our red bed inclination shallowing corrections have been dependent on estimates of hematite individual particle anisotropy using data fit to theoretical correction curves. We have developed a technique for preferentially extracting the detrital hematite particles in a sample in order to directly measure their individual particle anisotropy. The method involves crushing of the sample followed by ball milling and sieving to ensure that the rock particles are smaller than 4Φ. The resulting slurry was then placed in an ultrasonic cleaner for at least 24 hours and finally centrifuged at 1000 rpm for 20 minutes in order to separate the dense, gray iron oxide particles from the red pigmentary grains. The gray, iron oxide-rich slurry was collected by hand and circulated in a magnetic extraction apparatus. The magnetic separate was then collected over a period of two to three weeks. Small amounts of the magnetic separates where mixed in a slow-drying epoxy resin for 24 hours and placed in a DC magnetic field (100 mT to 180 mT) in order to align the grains. The bulk IRM anisotropy of the epoxy samples provides an average individual particle anisotropy for the magnetic grains. Separates were collected from samples of the Mauch Chunk Fm. of Pennsylvania, the Maringouin and the Shepody Fms of New Brunswick/ Nova Scotia and the Kapusaliang Fm. of northwestern China. IRM acquisitions experiments were performed in fields of up to 1.2 T in order to identify the magnetic mineralogies present. Remanence

  1. The use of electrical anisotropy measurements to monitor soil crack dynamics - laboratory evaluation

    NASA Astrophysics Data System (ADS)

    Sahraei, Amirhossein; Huisman, Johan Alexander; Zimmermann, Egon; Vereecken, Harry

    2016-04-01

    Swelling and shrinking of soil cracks is a key factor determining water fluxes in many irrigated soils. Most previous studies have used time-intensive and destructive methods for crack characterization, such as depth and volume determination from simplified geometrical measurements or liquid latex filling. Because of their destructive and time-consuming nature, these methods have only provided instantaneous estimates of the geometry and/or volume of cracks. The aim of this study is to evaluate the use of anisotropy in electrical resistivity measured with a square electrode array to determine crack depth dynamics. In a first step, the performance of the method was analyzed using a laboratory experiment where an artificial soil crack was emulated using a plastic plate in a water bath. Since cracking depth was precisely known, this experiment allowed to develop a method to estimate soil crack depth from measurements of the electrical anisotropy. In a second step, electrical anisotropy was measured during soil crack development within a soil monolith consisting of a mix of sand and bentonite. The cracking depth estimated from electrical measurement compared well with reference ruler measurements. These laboratory measurements inspired confidence in the use of electrical anisotropy for soil crack investigations, and consequently the developed methods will be applied to investigate soil crack dynamics in the field in a next step.

  2. A Instrument and Technique for Measuring the Anisotropy in the Cosmic Microwave Background Radiation

    NASA Astrophysics Data System (ADS)

    Wilson, Grant W.

    1997-09-01

    There is a wealth of information contained in the spatial temperature distribution of the Cosmic Microwave Background Radiation (CMB) >From the pioneering discovery of anisotropy by the COBE satellite to the latest balloon payloads and ground based observations, measurements of the CMB have become the cornerstone of our current understanding of the Universe. Currently, the second generation of CMB experiments are coming on-line. With improved detectors and novel observing strategies, these experiments are destined to make the transition from 'discovering' the anisotropy in the CMB to making precision measurements of the spatial correlation function. Herein I describe the most recent of these second generation experiments: the Medium Scale Anisotropy Measurement (MSAM II). MSAM II is a balloon-based telescope with a bolometric receiver cooled by an Adiabatic Demagnetization Refrigerator to 100 mK. MSAM II samples the sky with a 20 prime FWHM beam swept with a triangle wave at 2.5 Hz and will make a precision measurement of the spatial correlation function from 1 = 100 to 1 = 500. In addition to a comprehensive discussion of the fabrication and development of the cryogenic and optical systems of MSAM II, I present a novel method of estimating cosmological parameters from anisotropy measurements using a maximum Likelihood technique which employs the full covariance matrix of observations. This method has been used on the combined three years of MSAM I datasets to constrain the mass fraction of baryons in the universe, ΩB, as well as a number of other cosmological parameters.

  3. An efficient amplification pulse sequence for measuring chemical shift anisotropy under fast magic-angle spinning.

    PubMed

    Hung, Ivan; Gan, Zhehong

    2011-12-01

    A two-dimensional experiment for measuring chemical shift anisotropy (CSA) under fast magic-angle spinning (MAS) is presented. The chemical shift anisotropy evolution is amplified by a sequence of π-pulses that repetitively interrupt MAS averaging. The amplification generates spinning sideband manifolds in the indirect dimension separated by the isotropic shift along the direct dimension. The basic unit of the pulse sequence is designed based on the magic-angle turning experiment and can be concatenated for larger amplification factors. PMID:21962909

  4. Baseline measurements of terrestrial gamma radioactivity at the CEBAF site

    SciTech Connect

    Wollenberg, H.A.; Smith, A.R.

    1991-10-01

    A survey of the gamma radiation background from terrestrial sources was conducted at the CEBAF site, Newport News, Virginia, on November 12--16, 1990, to provide a gamma radiation baseline for the site prior to the startup of the accelerator. The concentrations and distributions of the natural radioelements in exposed soil were measured, and the results of the measurements were converted into gamma-ray exposure rates. Concurrently, samples were collected for laboratory gamma spectral analyses.

  5. Upper and lower mantle anisotropy inferred from comprehensive SKS and SKKS splitting measurements from India

    NASA Astrophysics Data System (ADS)

    Roy, Sunil K.; Ravi Kumar, M.; Srinagesh, D.

    2014-04-01

    In this study, we investigate the upper mantle anisotropy beneath India using high quality SKS and SKKS waveforms from 382 teleseismic earthquakes recorded at 119 broadband seismic stations. In addition, we present evidence for anisotropy in the D″ layer beneath southeast Asia using SKS and SKKS splitting discrepancies on the same seismogram. During this exercise, we obtain 200 new splitting measurements from 35 stations recently deployed in the Indo-Gangetic plains (IGP), central India and northeast India. While the delay times between the fast and slow axes of anisotropy (δt) range from 0.3 to 1.7 s, the fast polarization azimuths (Φ) at a majority of stations in the IGP and central India coincide with the absolute plate motion of India implying shear at the base of the lithosphere as the dominant mechanism for forging anisotropy. However, stations in NE India reveal fast polarization azimuths mainly in the ENE-WSW direction suggestive of lithospheric strain induced by the ongoing Indo-Eurasian collision. Our analysis for D″ anisotropy yielded a total of 100 SKS-SKKS pairs, which can be categorized into those exhibiting (I) null measurements for one phase and significant splitting for the other phase, (II) null measurement for both the phases, (III) significant splitting for both the phases. A pair is considered to be anomalous if the splitting difference between SKS and SKKS is ⩾0.5 s and the individual split time is ⩾0.5 s. Using this criterion, we obtain 12 measurements under category III and 9 under category I that show a null measurement for SKS and large splitting for the SKKS phase. Further, we quantify the strength of the lower mantle anisotropy by correcting the SKKS measurement for the upper mantle anisotropy obtained by the SKS phase on the same seismogram. The SKS delay times are found to be consistently less than SKKS times, suggesting that the SKS phases do not capture the lower mantle anisotropy in comparison to their SKKS counterparts

  6. Measuring high-energy {gamma} rays with Ge detectors

    SciTech Connect

    Lipoglavsek, M.; Likar, A.; Vencelj, M.; Vidmar, T.; Bark, R. A.; Gueorguieva, E.; Komati, F.; Lawrie, J. J.; Maliage, S. M.; Mullins, S. M.; Murray, S. H. T.; Ramashidzha, T. M.

    2006-04-26

    Gamma rays with energies up to 21 MeV were measured with Ge detectors. Such {gamma} rays were produced in the 208Pb(p,{gamma})209Bi reaction. The position of the 2g9/2 single proton orbit in 209Bi has been determined indicating the size of the Z=126 shell gap.

  7. Measuring Cosmological Parameters with Gamma Ray Bursts

    NASA Astrophysics Data System (ADS)

    Amati, Lorenzo; Della Valle, Massimo

    2013-12-01

    In a few dozen seconds, gamma ray bursts (GRBs) emit up to 1054 erg in terms of an equivalent isotropically radiated energy Eiso, so they can be observed up to z 10. Thus, these phenomena appear to be very promising tools to describe the expansion rate history of the universe. Here, we review the use of the Ep,i-Eiso correlation of GRBs to measure the cosmological density parameter ΩM. We show that the present data set of GRBs, coupled with the assumption that we live in a flat universe, can provide independent evidence, from other probes, that ΩM 0.3. We show that current (e.g. Swift, Fermi/GBM, Konus-WIND) and forthcoming gamma ray burst (GRB) experiments (e.g. CALET/GBM, SVOM, Lomonosov/UFFO, LOFT/WFM) will allow us to constrain ΩM with an accuracy comparable to that currently exhibited by Type Ia supernovae (SNe-Ia) and to study the properties of dark energy and their evolution with time.

  8. Variability and origin of seismic anisotropy across eastern Canada: Evidence from shear wave splitting measurements

    NASA Astrophysics Data System (ADS)

    Darbyshire, F. A.; Bastow, I. D.; Forte, A. M.; Hobbs, T. E.; Calvel, A.; Gonzalez-Monteza, A.; Schow, B.

    2015-12-01

    Measurements of seismic anisotropy in continental regions are frequently interpreted with respect to past tectonic processes, preserved in the lithosphere as "fossil" fabrics. Models of the present-day sublithospheric flow (often using absolute plate motion as a proxy) are also used to explain the observations. Discriminating between these different sources of seismic anisotropy is particularly challenging beneath shields, whose thick (≥200 km) lithospheric roots may record a protracted history of deformation and strongly influence underlying mantle flow. Eastern Canada, where the geological record spans ˜3 Ga of Earth history, is an ideal region to address this issue. We use shear wave splitting measurements of core phases such as SKS to define upper mantle anisotropy using the orientation of the fast-polarization direction ϕ and delay time δt between fast and slow shear wave arrivals. Comparison with structural trends in surface geology and aeromagnetic data helps to determine the contribution of fossil lithospheric fabrics to the anisotropy. We also assess the influence of sublithospheric mantle flow via flow directions derived from global geodynamic models. Fast-polarization orientations are generally ENE-WSW to ESE-WNW across the region, but significant lateral variability in splitting parameters on a ≤100 km scale implies a lithospheric contribution to the results. Correlations with structural geologic and magnetic trends are not ubiquitous, however, nor are correlations with geodynamically predicted mantle flow directions. We therefore consider that the splitting parameters likely record a combination of the present-day mantle flow and older lithospheric fabrics. Consideration of both sources of anisotropy is critical in shield regions when interpreting splitting observations.

  9. High glucose causes delayed fetal lung maturation as measured by fluorescence anisotropy.

    PubMed

    Gewolb, I H; Unger, M E; Merdian, W; Deutsch, J; Cavalieri, R L

    1993-06-15

    Fluorescence anisotropy has been used to estimate the microviscosity of the surfactant phospholipid bilayer and no predict fetal lung maturity in human amniotic fluid; its usefulness in in vitro systems has been recently demonstrated. To investigate the effect of high glucose on lung development, anisotropy measurements were performed on 20-day fetal rat lung explant homogenates and culture media after culture for 48 hours in medium containing final concentrations of 10, 50, and 100mM glucose. Anisotropy of lung tissue cultured in 100mM glucose was significantly increased when compared to those cultured in 10mM glucose (p < .01). After 48 hours, the media from samples grown in 100mM glucose had significantly higher anisotropy (.2210 +/- .0031) than did media from explants grown in 50mM glucose (.2027 +/- .0079; p < .05), or in 10mM glucose (.1886 +/- .0046; p < .001). Relative fluorescence intensity of explants grown in 100mM glucose was 74.4 +/- 5.7% of those grown in 10mM glucose (p < .01). Fluorescence intensity of media was also decreased by 15-30% under higher glucose considerations (p < .05). These data suggest that surfactant synthesized and secreted under high glucose conditions, such as exist in the infant of the diabetic gestation, may have qualitative as well as quantitative changes. PMID:8512578

  10. Fluid-dependent anisotropy and experimental measurements in synthetic porous rocks with controlled fracture parameters

    NASA Astrophysics Data System (ADS)

    Ding, Pinbo; Di, Bangrang; Wei, Jianxin; Li, Xiangyang; Deng, Yinghua

    2014-02-01

    In this study, we analyse the influence of fluid on P- and S-wave anisotropy in a fractured medium. Equivalent medium theories are used to describe the relationship between the fluid properties and the rock physics characteristics in fractured rocks, and P-wave and S-wave velocities and anisotropy are considered to be influenced by fluid saturation. However, these theoretical predictions require experimental measurement results for calibration. A new construction method was used to create synthetic rock samples with controlled fracture parameters. The new construction process provides synthetic rocks that have a more realistic mineral composition, porous structure, cementation and pressure sensitivity than samples used in previous research on fractured media. The synthetic rock samples contain fractures which have a controlled distribution, diameter, thickness and fracture density. In this study, the fracture diameter was about 4 mm, the thickness of fractures was about 0.06 mm, and the fracture density in the two fractured rock samples was about 3.45%. SEM images show well-defined penny-shaped fractures of 4 mm in length and 0.06 mm in width. The rock samples were saturated with air, water and oil, and P- and S-wave velocities were measured in an ultrasonic measurement system. The laboratory measurement results show that the P-wave anisotropy is strongly influenced by saturated fluid, and the P-wave anisotropy parameter, ɛ, has a much larger value in air saturation than in water and oil saturations. The S-wave anisotropy decreases when the samples are saturated with oil, which can be caused by high fluid viscosity. In the direction perpendicular to the fractures (the 0° direction), shear-wave splitting is negligible, and is similar to the blank sample without fractures, as expected. In the direction parallel to the fractures (the 90° direction) shear-wave splitting is significant. The fractured rock samples show significant P- and S-wave anisotropy caused by

  11. Introducing anisotropic Minkowski functionals and quantitative anisotropy measures for local structure analysis in biomedical imaging

    NASA Astrophysics Data System (ADS)

    Wismüller, Axel; De, Titas; Lochmüller, Eva; Eckstein, Felix; Nagarajan, Mahesh B.

    2013-03-01

    The ability of Minkowski Functionals to characterize local structure in different biological tissue types has been demonstrated in a variety of medical image processing tasks. We introduce anisotropic Minkowski Functionals (AMFs) as a novel variant that captures the inherent anisotropy of the underlying gray-level structures. To quantify the anisotropy characterized by our approach, we further introduce a method to compute a quantitative measure motivated by a technique utilized in MR diffusion tensor imaging, namely fractional anisotropy. We showcase the applicability of our method in the research context of characterizing the local structure properties of trabecular bone micro-architecture in the proximal femur as visualized on multi-detector CT. To this end, AMFs were computed locally for each pixel of ROIs extracted from the head, neck and trochanter regions. Fractional anisotropy was then used to quantify the local anisotropy of the trabecular structures found in these ROIs and to compare its distribution in different anatomical regions. Our results suggest a significantly greater concentration of anisotropic trabecular structures in the head and neck regions when compared to the trochanter region (p < 10-4). We also evaluated the ability of such AMFs to predict bone strength in the femoral head of proximal femur specimens obtained from 50 donors. Our results suggest that such AMFs, when used in conjunction with multi-regression models, can outperform more conventional features such as BMD in predicting failure load. We conclude that such anisotropic Minkowski Functionals can capture valuable information regarding directional attributes of local structure, which may be useful in a wide scope of biomedical imaging applications.

  12. Micromagnetic studies on measurements of crystalline anisotropy and magnetostriction in disk media

    NASA Astrophysics Data System (ADS)

    Li, Hongjia; Wei, Dan

    2011-04-01

    Measurements of intrinsic magnetic parameters are important in the study of magnetic devices. A micromagnetic model is set up for a perpendicular disk media, including a recording layer (RL, CoCrPt-SiO2, 6 nm), a 12-nm nonmagnetic interlayer and an amorphous soft underlayer (a-SUL, FeCo, 42 nm), in order to study the measurement methods of the crystalline anisotropy and magnetostriction constants in the RL. The effects of the a-SUL on the magnetic properties of the RL are studied by calculating the hysteresis loops. The contributions of the RL and a-SUL to the torque curves of the whole media are calculated respectively. If the intrinsic stress at the interface between the RL and interlayer is along one of the in-plane directions, the crystalline anisotropy constant K1 and magnetostriction field Hms can be determined simultaneously from the simulated in-plane torque curves.

  13. Iron and cadmium capture gamma-ray photofission measurements

    SciTech Connect

    Williamson, T.G. . Dept. of Nuclear Engineering); Lamaze, G.P.; Gilliam, D.M.; Eisenhauer, C.M. )

    1990-01-01

    Photofission measurements have been made in {sup 238}U, {sup 232}Th, and {sup 237}Np in iron and cadmium capture gamma-ray spectra in cylindrical neutron-driven gamma-ray sources in the thermal column of the National Bureau of Standards (NBS) Reactor. The gamma-ray source strength was measured with neutron activation foils and by direct counting of activations produced in the metal cylinders. Photofission measurements were made with NBS miniature fission chambers. The integral photofission cross sections were compared with differential measurements by integrating the capture gamma-ray spectra with measured cross-section shapes. The integral cross sections measured in the capture gamma-ray fields are lower than the cross sections calculated from measured differential data.

  14. Measurement of optical anisotropy in ultrathin films using surface plasmon resonance

    NASA Astrophysics Data System (ADS)

    Devanarayanan, V. P.; Manjuladevi, V.; Poonia, Monika; Gupta, R. K.; Gupta, Sanjeev K.; Akhtar, Jamil

    2016-01-01

    The optical phenomenon, surface plasmon resonance (SPR) is employed for the measurement of optical anisotropy in the ultrathin films fabricated through Langmuir-Blodgett (LB) and self-assembled monolayer (SAM) techniques onto 50 nm gold film supported on BK7 glass substrates. The resonance angle (RA) is measured using a home built setup in Kretschmann configuration. The LB films and SAM can provide a single layer of highly ordered and organized molecules on the two dimensional surface. If the film forming molecules are anisotropic, their organization in the LB films and SAM can yield an anisotropic film due to tilt of the molecules with respect to the surface normal. The SPR spectra are recorded for the two orthogonal directions of the film with respect to the plane of incidence. The spectra are simulated by modeling the Fresnel's reflection from 4-layers viz., prism, gold, ultrathin films and air; and the real and imaginary parts of refractive index are estimated. Our study shows the metallic and dielectric nature of the LB films of bundles of single walled carbon nanotubes (SWCNTs) when the long axis of SWCNTs are aligned parallel and perpendicular to plane of incidence, respectively. The optical anisotropy was estimated from the change in real part of refractive index (Δnr) of the ultrathin films measured in the orthogonal directions. In addition, we have also studied such optical anisotropy in the LB film of cadmium-stearate and self-assembled monolayer of octadecanethiol.

  15. Seismic anisotropy of the crust: electron-backscatter diffraction measurements from the Basin and Range

    NASA Astrophysics Data System (ADS)

    Erdman, Monica E.; Hacker, Bradley R.; Zandt, George; Seward, Gareth

    2013-11-01

    Crystal preferred orientations were measured in a suite of rocks from three locations in the Basin and Range using electron-backscatter diffraction. Anisotropic velocities were calculated for all rocks using single-crystal stiffnesses, the Christoffel equation and Voigt-Reuss-Hill averaging. Anisotropic velocities were calculated for all three crustal sections using these values combined with rock proportions as exposed in the field. One suite of rocks previously measured in the laboratory was used as a benchmark to evaluate the accuracy of the calculated velocities. Differences in the seismic anisotropy of the Funeral Mountains, Ruby Mountains and East Humboldt Range sections arise because of differences in mineralogy and strain, with the calc-silicate dominated Ruby Mountains section having higher P-wave speeds and VP/VS ratios because of the reduced quartz content. In all cases, the velocities show either transverse isotropy or nearly so, with a unique slow axis normal to the foliation. Velocity anisotropy can thus be used to infer the flow plane, but not the flow direction in typical crustal rocks. Areas with a subhorizontal foliation have minimal shear wave splitting for vertically propagating waves and are thus good places to measure mantle anisotropy using SKS-splitting.

  16. Petrophysical Characterization of Stony Meteorites Using Low Field Magnetic Susceptibility: Initial Results From Anisotropy Measurements

    NASA Astrophysics Data System (ADS)

    Smith, D. L.; Ernst, R. E.; Herd, R. K.; Claire, S.

    2004-05-01

    Low field magnetic susceptibility represents a fast, systematic and non-destructive technique of meteorite classification [1-4]. We previously reported measurements of bulk susceptibility, and its frequency dependence, along with a `proxy' measure of anisotropy, on 204 specimens from 108 different meteorites in the National Meteorite Collection of Canada [5,6]. Measurements were performed on a Sapphire Instruments Model 2B. Bulk susceptibility values followed expected trends, governed by metal content, with values increasing from LL, to L, to H, to E chondrites. Frequency dependence (19000 vs 825 Hz) was greatest in H and C chondrites. Aubrites (AUB) and Howardites (HOW) had the lowest. Anisotropy of magnetic susceptibility (AMS) was measured using a `proxy' approach: the mean value determined from a series of random sample orientations was compared with repeated measurements in one orientation. AUB, E chondrites and Martian SNCs had the largest inferred anisotropies, while LL and C chondrites had the lowest. Here we report initial results from a follow-up study. Quantitative measurements of the AMS were made on 67 stony meteorite specimens. AMS measurements [3,5,6,7,8,9] can provide information on the physical fabric of the meteorite, and may relate to its deformational history. Samples measured show significant degrees of anisotropy ranging from 1-50 % for an individual specimen (in parentheses is the number of specimens used in the class mean): AUB (5), Acapulcoites (1) and E chondrites (10) display the largest degrees of anisotropy, 40±11 (1 standard deviation), 34, and 24±10, respectively. These classes are followed by Diogenite (1) 20, H (13) 14±7 and L (10) 13±6 chondrites, Brachinite (1) 11, Ureilite (2) 8, Eucrite (4) 7±4, C chondrites (14) 6±3, and Rumurutiite (1) 4. These results match a similar trend based on the `proxy' method [5,6]: AUB and E chondrites were found to have the highest inferred anisotropies followed by tightly grouped H and L

  17. Novel Beta-Gamma Coincidence Measurements Using Phoswich Detectors

    SciTech Connect

    Ely, James H.; Aalseth, Craig E.; Hayes, James C.; Heimbigner, Tom R.; McIntyre, Justin I.; Miley, Harry S.; Panisko, Mark E.; Ripplinger, Mike D.

    2003-09-30

    The PNNL has developed an Automated Radio-xenon Sampler/Analyzer (ARSA) for the CTBT to measure four radio-xenon isotopes using a beta-gamma coincidence counting detector. A novel method to measure beta-gamma coincidences using a phoswich detector with state-of-the-art pulse shape discrimination techniqueses has been investigated.

  18. Reduction of anisotropy influence and contacting effects in in-vitro bioimpedance measurements

    NASA Astrophysics Data System (ADS)

    Guermazi, M.; Kanoun, O.; Derbel, N.

    2013-04-01

    Experimental procedure is a decisive part in in-vitro bioimpedance measurement in order to get reproducible measurements. An electrode configuration is proposed to avoid several disadvantages produced by needle electrodes and circular non-penetrating electrode. The proposed electrode geometry reduces the influence of anisotropy and allows simultaneously a good probe contacting. We propose an experimental method to avoid the appearance of bacteria and to reduce water loss in meat during experiment post-mortem. The results show that electrode configuration with the developed experimental method have ensured reproducible measurements during a long period of 14 days post-mortem.

  19. Inelastic cross sections from gamma-ray measurements

    SciTech Connect

    Nelson, Ronald Owen

    2010-12-06

    Measurements of gamma rays following neutron induced reactions have been studied with the Germanium Array for Neutron-induced Excitations (GEANIE) at the Los Alamos Neutron Science Center (LANSCE) for many years. Gamma-ray excitation functions and coincidence studies provide insight into nuclear reaction mechanisms as well as expanding our knowledge of energy levels and gamma-rays. Samples studied with Ge detectors at LANSCE range from Be to Pu. Fe, Cr and Ti have been considered for use as reference cross sections. An overview of the measurements and efforts to create a reliable neutron-induced gamma-ray reference cross section will be presented.

  20. Field Variation of Low-field Anisotropy of Magnetic Susceptibility of Rocks: Measurement Problems

    NASA Astrophysics Data System (ADS)

    Hrouda, F.

    Theory of low-field anisotropy of magnetic susceptibility (AMS) assumes linear rela- tionship between magnetization and magnetizing field. This assumption is precisely valid in diamagnetic and paramagnetic minerals by definition, while in ferrimagnetic and antiferromagnetic minerals this relationship is in general non-linear, represented by hysteresis loop, being linear only in very weak fields in which the initial suscep- tibility is measured. Recently, it has been shown that, in using common measuring fields, the initial susceptibility is always measured in magnetite, while in pyrrhotite, hematite, and titanomagnetite the measured susceptibility may often be outside the initial susceptibility range. The field variation of low-field AMS results in lowering the quality of the fit of the susceptibility ellipsoid to the measured data and in mis- estimating the degree of anisotropy. Fortunately, the orientations of the principal sus- ceptibilities are virtually field-independent. The problem can be solved in basically three ways. The simplest way is using very weak measuring fields (less than 10 A/m), but this can result in significant lowering sensitivity and precision. The other way is to respect the non-linearity and measure the susceptibility in so many directions that contour diagram of directional susceptibilities can be presented instead of suscepti- bility ellipsoid. The third way is to measure the AMS in at least two fields within the Rayleigh law range and calculate the initial directional susceptibilities from which the AMS can be correctly determined using linear theory.

  1. Measurements of seismic anisotropy and fracture compliances in synthetic fractured media

    NASA Astrophysics Data System (ADS)

    Far, Mehdi E.; de Figueiredo, Jose J. S.; Stewart, Robert R.; Castagna, John P.; Han, De-Hua; Dyaur, Nikolay

    2014-06-01

    Ultrasonic velocities were measured on a stack of synthetic materials (Plexiglass plates), at low (90/120 kHz, long wavelength range: 12-23 mm) and high (431/480 kHz, short wavelength range: 1-6 mm) frequencies. The Plexiglass plates were pressed together with uniaxial normal stress. The ultrasonic measurements were repeated under different uniaxial stresses with and without circular rubber inclusions between the plates. The stress dependence of measured P-wave velocities is more pronounced (about 200 m s-1 difference) at low frequency compared to the high frequency measurements. S-wave velocity measurements in the vertical direction (perpendicular to plates) and horizontal direction with polarization perpendicular to the plates show that, without rubber inclusions, the model can be approximated as a vertical transverse isotropy (VTI) medium (difference of about 20 m s-1between the two S-wave velocities for stresses higher than 6 MPa), whereas, for the case with inclusions, there is a significant difference (about 350 m s-1 for stresses higher than 6 MPa). The difference in vertically propagating and horizontally propagating vertically polarized S-wave velocities indicates that the medium is inhomogeneous at these wavelengths. Ultrasonic velocity measurements were used to calculate fracture compliances and VTI anisotropy parameters. For both experiments (with and without rubber disc inclusion), fracture compliances and also absolute values of VTI anisotropy parameters, decrease with increasing stress and frequency. For our experiments, Thomsen's anisotropy parameter γ is highly correlated to ɛ and η (with average correlation coefficients of about 95 per cent). For all measurements, the medium showed positive anellipticity (i.e. ɛ-δ > 0). In all cases, the tangential compliance was greater than the normal compliance. For experiments without inclusions, the normal to tangential compliance ratios show an increasing trend with increasing normal stress. For

  2. Measurements of Branching Fractions for B+ -> rho+ gamma, B0 -> rho0 gamma, and B0 -> omega gamma

    SciTech Connect

    Aubert, B

    2008-08-15

    The authors present branching fraction measurements for the radiative decays B{sup +} {yields} {rho}{sup +}{gamma}, B{sup 0} {yields} {rho}{sup 0}{gamma}, and B{sup 0} {yields} {omega}{gamma}. The analysis is based on a data sample of 465 million B{bar B} events collected with the BABAR detector at the PEP-II asymmetric-energy B Factory located at the Stanford Linear Accelerator Center (SLAC). They find {Beta}(B{sup +} {yields} {rho}{sup +}{gamma}) = (1.20{sub -0.37}{sup +0.42} {+-} 0.20) x 10{sup -6}, {Beta}(B{sup 0} {yields} {rho}{sup 0}{gamma}) = (0.97{sub -0.22}{sup +0.24} {+-} 0.06) x 10{sup -6}, and a 90% C.L. upper limit {Beta}(B{sup 0} {yields} {omega}{gamma}) < 0.9 x 10{sup -6}, where the first error is statistical and the second is systematic. They also measure the isospin-violating quantity {Lambda}(B{sup +} {yields} {rho}{sup +}{gamma})/2{Lambda}(B{sup 0} {yields} {rho}{sup 0}{gamma}) - 1 = -0.43{sub -0.22}{sup +0.25} {+-} 0.10.

  3. Theory of scan plane flux anisotropies. [in spacecraft detector measurements of planetary magnetospheres

    NASA Technical Reports Server (NTRS)

    Northrop, T. G.; Thomsen, M. F.

    1980-01-01

    When a spacecraft detector measures particle flux as a function of look direction in a plane (the scan plane), anisotropy is often seen. This anisotropy is caused by spatial gradients, by E x B particle drift, and by various spectral and geometric effects. This paper treats all of these effects systematically, starting from the nonrelativistic Vlasov equation. The general analysis is applied to a simple model of an anisotropic distribution to give a relation between the E x B drift, the gradient and the experimentally observed first, second, and third harmonics of the flux as a function of angle in the scan plane. Even with an assumed model, anisotropy observations in one plane alone do not suffice to determine the E x B drift velocity and the spatial gradient independently. If the E x B velocity is assumed (e.g., the corotational velocity in a rotating planetary magnetosphere), the spatial gradient may be deduced, and from it the time rate of change of flux in a nonrotating frame of reference.

  4. 3 mm Anisotropy Measurement: On the Quadrupole Component in theCosmic Background Radiation

    SciTech Connect

    Lubin, Philip M.; Epstein, Gerald L.; Smoot, George F.

    1982-11-01

    We have mapped the large-scale anisotropy in the cosmic background radiation at 3 mm wavelength using a liquid-helium-cooled balloon-borne radiometer sensitive enough to detect the dipole in one gondola rotation (1 minute). Statistical errors on the dipole and quadrupole components are below 0.1 mK with less than 0.1 m K galactic contribution. We find a dipole consistent with previous measurements but disagree with recent quadrupole reports. The measurement is also useful in searching for spectral distortions.

  5. Resistivity anisotropy measured using four probes in epitaxial graphene on silicon carbide

    NASA Astrophysics Data System (ADS)

    Kobayashi, Keisuke; Tanabe, Shinichi; Tao, Takuto; Okumura, Toshio; Nakashima, Takeshi; Aritsuki, Takuya; O, Ryong-Sok; Nagase, Masao

    2015-03-01

    The electronic transport of epitaxial graphene on silicon carbide is anisotropic because of the anisotropy of the surface structure of the substrate. In this Letter, we present a new method for measuring anisotropic transport based on the van der Pauw method. This method can measure anisotropic transport on the macroscopic scale without special equipment or device fabrication. We observe an anisotropic resistivity with a ratio of maximum to minimum of 1.62. The calculated maximum mobility is 2876 cm2·V-1·s-1, which is 1.43 times higher than that obtained by the standard van der Pauw method.

  6. QUALITY CONTROL FOR ENVIRONMENTAL MEASUREMENTS USING GAMMA-RAY SPECTROMETRY

    EPA Science Inventory

    This report describes the quality control procedures, calibration, collection, analysis, and interpretation of data in measuring the activity of gamma ray-emitting radionuclides in environmental samples. Included in the appendices are basic data for selected gamma ray-emitting ra...

  7. Impact of Emission Anisotropy on Fluorescence Spectroscopy and FRET Distance Measurements

    PubMed Central

    Ivanov, Vassili; Li, Min; Mizuuchi, Kiyoshi

    2009-01-01

    Abstract The objective of this report is to provide a practical and improved method for estimating Förster resonance energy transfer distance measurement error due to unknown angles in the dipole orientation factor based on emission anisotropy measurements. We improve on the method of Dale et al. (1979), which has minor mistakes and is frequently interpreted in overly optimistic ways in the literature. To facilitate proper fluorescence intensity measurements, we also evaluated instrument parameters that could impact the measurement. The apparent fluorescence intensity of isotropic samples depends on the sample emission anisotropy, fluorometer geometry, and optical apertures. We separate parameters of the sample, and those of the cylindrically symmetric illumination source and detector in the equations describing results of unpolarized and polarized fluorescence intensity measurements. This approach greatly simplifies calculations compared with the more universal method of Axelrod (1989). We provide a full computational method for calculating the Förster resonance energy transfer distance error and present a graph describing distance error in the simplest case. PMID:19651051

  8. Impact of emission anisotropy on fluorescence spectroscopy and FRET distance measurements.

    PubMed

    Ivanov, Vassili; Li, Min; Mizuuchi, Kiyoshi

    2009-08-01

    The objective of this report is to provide a practical and improved method for estimating Förster resonance energy transfer distance measurement error due to unknown angles in the dipole orientation factor based on emission anisotropy measurements. We improve on the method of Dale et al. (1979), which has minor mistakes and is frequently interpreted in overly optimistic ways in the literature. To facilitate proper fluorescence intensity measurements, we also evaluated instrument parameters that could impact the measurement. The apparent fluorescence intensity of isotropic samples depends on the sample emission anisotropy, fluorometer geometry, and optical apertures. We separate parameters of the sample, and those of the cylindrically symmetric illumination source and detector in the equations describing results of unpolarized and polarized fluorescence intensity measurements. This approach greatly simplifies calculations compared with the more universal method of Axelrod (1989). We provide a full computational method for calculating the Förster resonance energy transfer distance error and present a graph describing distance error in the simplest case. PMID:19651051

  9. MAXIMA-1: A Measurement of the Cosmic Microwave Background Anisotropy on Angular Scales of 10' to 5 degrees

    DOE R&D Accomplishments Database

    Ade, P.; Balbi, A.; Bock, J.; Borrill, J.; Boscaleri, A.; de Bernardis, P.; Ferreira, P. G.; Hanany, S.; Hristov, V. V.; Jaffe, A. H.; Lange, A. E.; Lee, A. T.; Mauskopf, P. D.; Netterfield, C. B.; Oh, S.; Pascale, E.; Rabii, B.; Richards, P. L.; Smoot, G. F.; Stompor, R.; Winant,C. D.; Wu, J. H. P.

    2005-06-04

    We present a map and an angular power spectrum of the anisotropy of the cosmic microwave background (CMB) from the first flight of MAXIMA. MAXIMA is a balloon-borne experiment with an array of 16 bolometric photometers operated at 100 mK. MAXIMA observed a 124 deg{sup 2} region of the sky with 10' resolution at frequencies of 150, 240 and 410 GHz. The data were calibrated using in-flight measurements of the CMB dipole anisotropy. A map of the CMB anisotropy was produced from three 150 and one 240 GHz photometer without need for foreground subtractions.

  10. Measurement and Calculation of Gamma Radiation from HWZPR Reactor

    SciTech Connect

    Jalali, Majid

    2006-07-01

    HWZPR is a research reactor with natural uranium fuel, D{sub 2}O moderator and graphite reflector with maximum power of 100 W. It is a suitable means for theoretical research and heavy water reactor experiments. Neutrons from the core participate in different nuclear reactions by interactions with fuel, moderator, graphite and the concrete around the reactor. The results of these interactions are the production of prompt gammas in the environment. Useful information is gained by the reactor gamma spectrum measurement from point of view of relative quantity and energy distribution of direct and scattered radiations. Reactor gamma ray spectrum has been gathered in different places around the reactor by HPGe detector. In analysis of these spectra, {sup 1}H(n,{gamma}){sup 2}H, {sup 16}O(n,n'{gamma}){sup 16}O, {sup 2}H(n,{gamma}){sup 3}H and {sup 238}U(n,{gamma}){sup 239}U reactions occurring in reactor moderator and fuel, are important. The measured spectrum has been primarily estimated by the MCNP code. There is agreement between the code and the experiments in some points. The scattered gamma rays from {sup 27}Al (n,{gamma}){sup 28}Al reaction in the reactor tank, are the most among the gammas scattered in the reactor environment. Also the dose calculations by MCNP code show that 72% of gamma dose belongs to the energy range 3-11 MeV from reactor gamma spectrum and the danger of exposure from the reactor high-energy photons is serious. (author)

  11. Guided modes measurements on optical thin films with high structurally induced anisotropy

    NASA Astrophysics Data System (ADS)

    Jaenchen, Heidrun; Endelema, D.; Kaiser, Norbert; Flory, Francois

    1996-08-01

    Precise determination of the main refractive indices of biaxial anisotropic coatings is essential for the calculation of their optical performance. Measurements based on wave guiding methods have proved to yield excellent results with these layers. A comprehensive study on coatings with relatively low anisotropy, obliquely deposited under angles of 32 degrees or less, was done before, but coatings of higher structural anisotropy have not been concerned yet. With higher deposition angels, new problems arise because the microstructure deviates more and more from the model, and the column inclination angle has an increasing influence on the mathematical separation of the main refractive indices. In a theoretical study, this effect is shown to limit the precision and reliability of the method. Experimental results on HfO2 thin films, deposited under 0 degrees, 30 degrees, 45 degrees, and 60 degrees, will be given. They were achieved using additional information about the coatings from transmission measurements between crossed polarizers and compared to results from ellipsometric and spectral photometric measurements. All measurements were performed at a wavelength of 632.8 nm.

  12. Measurment of B Decays to phi K gamma

    SciTech Connect

    Aubert, B.

    2006-11-28

    The authors search for the decays B{sup -} {yields} {phi}K{sup -}{gamma} and {bar B}{sup 0} {yields} {phi}{bar K}{sup 0}{gamma} in a data sample of 228 million B{bar B} pairs collected at the {Upsilon}(4S) resonance with the BABAR detector. They measure the branching fraction {Beta}(B{sup -} {yields} {phi}K{sup -}{gamma}) = (3.5 {+-} 0.6 {+-} 0.4) x 10{sup -6} and set an upper limit {Beta}({bar B}{sup 0} {yields} {phi}{bar K}{sup 0}{gamma}) < 2.7 x 10{sup -6} at the 90% confidence level. They also measure the direct CP asymmetry in B{sup -} {yields} {phi}K{sup -}{gamma}, {Alpha}{sub CP} = (-26 {+-} 14 {+-} 5)%. The uncertainties are statistical and systematic, respectively.

  13. Alignment Measurements of the Microwave Anisotropy Probe (MAP) Instrument in a Thermal/Vacuum Chamber

    NASA Technical Reports Server (NTRS)

    Hill, Michael D.; Herrera, Acey A.; Crane, J. Allen; Packard, Edward A.; Aviado, Carlos; Sampler, Henry P.

    2000-01-01

    The Microwave Anisotropy Probe (MAP) Observatory, scheduled for a fall 2000 launch, is designed to measure temperature fluctuations (anisotropy) and produce a high sensitivity and high spatial resolution (approximately 0.2 degree) map of the cosmic microwave background (CMB) radiation over the entire sky between 22 and 90 GHz. MAP utilizes back-to-back Gregorian telescopes to focus the microwave signals into 10 differential microwave receivers, via 20 feed horns. Proper alignment of the telescope reflectors and the feed horns at the operating temperature of 90 K is a critical element to ensure mission success. We describe the hardware and methods used to validate the displacement/deformation predictions of the reflectors and the microwave feed horns during thermal/vacuum testing of the reflectors and the microwave instrument. The smallest deformation predictions to be measured were on the order of +/- 0.030 inches (+/- 0.762 mm). Performance of these alignment measurements inside a thermal/vacuum chamber with conventional alignment equipment posed several limitations. The most troublesome limitation was the inability to send personnel into the chamber to perform the measurements during the test due to vacuum and the temperature extremes. The photogrammetry (PG) system was chosen to perform the measurements since it is a non- contact measurement system, the measurements can be made relatively quickly and accurately, and the photogrammetric camera can be operated remotely. The hardware and methods developed to perform the MAP alignment measurements using PG proved to be highly successful. The measurements met the desired requirements, for the metal structures enabling the desired distortions to be measured resolving deformations an order of magnitude smaller than the imposed requirements. Viable data were provided to the MAP Project for a full analysis of the on-orbit performance of the Instrument's microwave system.

  14. Measuring the charged pion polarizability in the gamma gamma -> pi+pi- reaction

    SciTech Connect

    Lawrence, David W.; Miskimen, Rory A.; Mushkarenkov, Alexander Nikolaevich; Smith, Elton S.

    2013-08-01

    Development has begun of a new experiment to measure the charged pion polarizability $\\alpha_{\\pi}-\\beta_{\\pi}$. The charged pion polarizability ranks among the most important tests of low-energy QCD presently unresolved by experiment. Analogous to precision measurements of $\\pi^{\\circ}\\rightarrow\\gamma\\gamma$ that test the intrinsic odd-parity (anomalous) sector of QCD, the pion polarizability tests the intrinsic even-parity sector of QCD. The measurement will be performed using the $\\gamma\\gamma\\rightarrow\\pi^{+{}}\\pi^{-{}}$ cross section accessed via the Primakoff mechanism on nuclear targets using the GlueX detector in Hall D at Jefferson Lab. The linearly polarized photon source in Hall-D will be utilized to separate the Primakoff cross-section from coherent $\\rho^{\\circ}$ production.

  15. A 145-GHz interferometer for measuring the anisotropy of the cosmic microwave background

    NASA Astrophysics Data System (ADS)

    Doriese, William Bertrand

    This thesis presents the design, construction, testing, and preliminary data analysis of MINT, the Millimeter INTerferometer. MINT is a 145-GHz, four-element interferometer designed to measure the anisotropy of the Cosmic Microwave Background (CMB) at spherical harmonics of ℓ = 800 to 1900. In this region of ℓ-space, the CMB angular power spectrum should exhibit an exponential damping due to a pair of effects related to the finite thickness of the last-scattering surface: photon diffusion and line-of-sight projection. Measurements in this region have already been made at 31 GHz by the Cosmic Background Imager (CBI). MINT's goal is to complement CBI by extending these results to a higher frequency that is much less prone to extra-galactic point-source contamination. MINT's mission is also complementary to that of the Microwave Anisotropy Probe (MAP) satellite. MINT observed the CMB in November and December, 2001, from an altitude of 17,000 feet in the Atacama Desert of northern Chile. We describe the performance of the instrument during the observing campaign. Based on radiometric hot/cold-load tests, the SIS-mixer-based receivers are found to have an average receiver noise temperature (double sideband) of 39 K in a 2-GHz IF bandwidth. The typical atmosphere contribution is 5 K. We assess the phase stability, gain stability, pointing accuracy, and overall sensitivity of the interferometer via observations of Mars and Jupiter, and find that the instrument is sufficiently stable to allow an ultimate experimental sensitivity at the few-μK level needed for detection of the CMB anisotropy.

  16. MEASUREMENTS OF SECONDARY COSMIC MICROWAVE BACKGROUND ANISOTROPIES WITH THE SOUTH POLE TELESCOPE

    SciTech Connect

    Lueker, M.; Reichardt, C. L.; Benson, B. A.; Cho, H.-M.; George, E. M.; Holzapfel, W. L.; Schaffer, K. K.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T.; Zahn, O.; Ade, P. A. R.; Aird, K. A.; De Haan, T.; Dobbs, M. A.; Holder, G. P.; Hall, N. R.; Halverson, N. W.

    2010-08-20

    We report cosmic microwave background (CMB) power-spectrum measurements from the first 100 deg{sup 2} field observed by the South Pole Telescope (SPT) at 150 and 220 GHz. On angular scales where the primary CMB anisotropy is dominant, l {approx}< 3000, the SPT power spectrum is consistent with the standard {Lambda}CDM cosmology. On smaller scales, we see strong evidence for a point-source contribution, consistent with a population of dusty, star-forming galaxies. After we mask bright point sources, anisotropy power on angular scales of 3000 < l < 9500 is detected with a signal-to-noise ratio {approx}>50 at both frequencies. We combine the 150 and 220 GHz data to remove the majority of the point-source power and use the point-source-subtracted spectrum to detect Sunyaev-Zel'dovich (SZ) power at 2.6{sigma}. At l = 3000, the SZ power in the subtracted bandpowers is 4.2 {+-} 1.5 {mu}K{sup 2}, which is significantly lower than the power predicted by a fiducial model using WMAP5 cosmological parameters. This discrepancy may suggest that contemporary galaxy cluster models overestimate the thermal pressure of intracluster gas. Alternatively, this result can be interpreted as evidence for lower values of {sigma}{sub 8}. When combined with an estimate of the kinetic SZ contribution, the measured SZ amplitude shifts {sigma}{sub 8} from the primary CMB anisotropy derived constraint of 0.794 {+-} 0.028 down to 0.773 {+-} 0.025. The uncertainty in the constraint on {sigma}{sub 8} from this analysis is dominated by uncertainties in the theoretical modeling required to predict the amplitude of the SZ power spectrum for a given set of cosmological parameters.

  17. A fluorescence anisotropy method for measuring protein concentration in complex cell culture media.

    PubMed

    Groza, Radu Constantin; Calvet, Amandine; Ryder, Alan G

    2014-04-22

    The rapid, quantitative analysis of the complex cell culture media used in biopharmaceutical manufacturing is of critical importance. Requirements for cell culture media composition profiling, or changes in specific analyte concentrations (e.g. amino acids in the media or product protein in the bioprocess broth) often necessitate the use of complicated analytical methods and extensive sample handling. Rapid spectroscopic methods like multi-dimensional fluorescence (MDF) spectroscopy have been successfully applied for the routine determination of compositional changes in cell culture media and bioprocess broths. Quantifying macromolecules in cell culture media is a specific challenge as there is a need to implement measurements rapidly on the prepared media. However, the use of standard fluorescence spectroscopy is complicated by the emission overlap from many media components. Here, we demonstrate how combining anisotropy measurements with standard total synchronous fluorescence spectroscopy (TSFS) provides a rapid, accurate quantitation method for cell culture media. Anisotropy provides emission resolution between large and small fluorophores while TSFS provides a robust measurement space. Model cell culture media was prepared using yeastolate (2.5 mg mL(-1)) spiked with bovine serum albumin (0 to 5 mg mL(-1)). Using this method, protein emission is clearly discriminated from background yeastolate emission, allowing for accurate bovine serum albumin (BSA) quantification over a 0.1 to 4.0 mg mL(-1) range with a limit of detection (LOD) of 13.8 μg mL(-1). PMID:24703214

  18. Gamma-ray dosimetry measurements of the Little Boy replica

    SciTech Connect

    Plassmann, E.A.; Pederson, R.A.

    1984-01-01

    We present the current status of our gamma-ray dosimetry results for the Little Boy replica. Both Geiger-Mueller and thermoluminescent detectors were used in the measurements. Future work is needed to test assumptions made in data analysis.

  19. Perspectives of the GAMMA-400 space observatory for high-energy gamma rays and cosmic rays measurements

    NASA Astrophysics Data System (ADS)

    Topchiev, N. P.; Galper, A. M.; Bonvicini, V.; Adriani, O.; Aptekar, R. L.; Arkhangelskaja, I. V.; Arkhangelskiy, A. I.; Bakaldin, A. V.; Bergstrom, L.; Berti, E.; Bigongiari, G.; Bobkov, S. G.; Boezio, M.; Bogomolov, E. A.; Bonechi, S.; Bongi, M.; Bottai, S.; Castellini, G.; Cattaneo, P. W.; Cumani, P.; Dalkarov, O. D.; Dedenko, G. L.; De Donato, C.; Dogiel, V. A.; Finetti, N.; Gorbunov, M. S.; Gusakov, Yu V.; Hnatyk, B. I.; Kadilin, V. V.; Kaplin, V. A.; Kaplun, A. A.; Kheymits, M. D.; Korepanov, V. E.; Larsson, J.; Leonov, A. A.; Loginov, V. A.; Longo, F.; Maestro, P.; Marrocchesi, P. S.; Men'shenin, A. L.; Mikhailov, V. V.; Mocchiutti, E.; Moiseev, A. A.; Mori, N.; Moskalenko, I. V.; Naumov, P. Yu; Papini, P.; Pearce, M.; Picozza, P.; Rappoldi, A.; Ricciarini, S.; Runtso, M. F.; Ryde, F.; Serdin, O. V.; Sparvoli, R.; Spillantini, P.; Stozhkov, Yu I.; Suchkov, S. I.; Taraskin, A. A.; Tavani, M.; Tiberio, A.; Tyurin, E. M.; Ulanov, M. V.; Vacchi, A.; Vannuccini, E.; Vasilyev, G. I.; Yurkin, Yu T.; Zampa, N.; Zirakashvili, V. N.; Zverev, V. G.

    2016-02-01

    The GAMMA-400 gamma-ray telescope is intended to measure the fluxes of gamma-rays and cosmic-ray electrons and positrons in the energy range from 100 MeV to several TeV. Such measurements concern the following scientific tasks: investigation of point sources of gamma-rays, studies of the energy spectra of Galactic and extragalactic diffuse emission, studies of gamma-ray bursts and gamma-ray emission from the Sun, as well as high precision measurements of spectra of high-energy electrons and positrons. Also the GAMMA- 400 instrument provides the possibility for protons and nuclei measurements up to knee. But the main goal for the GAMMA-400 mission is to perform a sensitive search for signatures of dark matter particles in high-energy gamma-ray emission. To fulfill these measurements the GAMMA-400 gamma-ray telescope possesses unique physical characteristics in comparison with previous and present experiments. The major advantage of the GAMMA-400 instrument is excellent angular and energy resolution for gamma-rays above 10 GeV. The GAMMA-400 experiment will be installed onboard of the Navigator space platform, manufactured by the NPO Lavochkin Association. The expected orbit will be a highly elliptical orbit (with apogee 300.000 km and perigee 500 km) with 7 days orbital period. An important profit of such an orbit is the fact that the full sky coverage will always be available for gamma ray astronomy.

  20. TLD measurements of gamma heating in heavy elements.

    NASA Technical Reports Server (NTRS)

    Reilly, H. J.; Robinson, R. A.; Peters, L. E., Jr.

    1971-01-01

    Measurements and calculations of gamma heating in polyethylene and lead containers were done and compared. The objective was to provide a workable method of getting good values for gamma heating in in-pile experiments containing materials of high atomic numbers. It was inferred that a combination of thermoluminescent dosimeter measurements, using Bragg-Gray theory, with photon transport calculations using the ANISN computer program, would meet this objective.

  1. Laboratory measurements of seismic velocity anisotropy of salt diapirs: Implications for wellbore stability and seismic processing

    NASA Astrophysics Data System (ADS)

    Vargas-Meleza, Liliana; Healy, David

    2013-04-01

    A set of ten evaporite samples collected from outcrops in a single diapiric province in Cape Breton Island (Canada) have been tested for seismic velocity anisotropy using three methods: 1) conventional ultrasonic pulse transmission method, where velocities are found from the travel times and the known dimensions of the samples. In order to obtain the entire suite of elastic constants, both P- and S-wave velocity measurements were taken in three different directions of cuboid rock samples. Velocities have been measured under dry, ambient conditions of temperature and pressure in halite-, gypsum- and anhydrite-dominated samples; 2) optical microscopy and scanning electron microscopy on thin sections to define the spatial distribution of minerals, their crystallographic preferred orientations (CPO); and 3) a numerical 'rock-recipe' approach based on Tatham et al. (2008) to calculate seismic velocity anisotropy using arbitrary composites of evaporite minerals and different CPOs. These three methods are then compared to understand the controlling factors of the anisotropic elastic properties. The elasticity data are used to guide geomechanical modeling for wellbore stability and to provide insights for the seismic data processing and seismic imaging of salt diapirs. Reference Tatham, D.J., Lloyd, G.E., Butler, R.W.H. and Casey, M, 2008, Amphibole and lower crustal seismic properties: Earth and Planetary Science Letters, 267, 118-128.

  2. Permeability, anisotropy and tortuosity measurements of pumices using X-ray computed microtomography

    NASA Astrophysics Data System (ADS)

    Degruyter, W.; Bachmann, O.; Burgisser, A.; Malaspinas, O.; Cnudde, V.; Masschaele, B.

    2007-12-01

    X-ray computed microtomography (μCT) has become a widely-applied technique to obtain density maps of heterogeneous media; it allows gathering non-destructively qualitative observations as well as quantitative information on the 3D geometries of multi-phase samples. In this study, we obtained 3D images of different pumice types found in the rhyolitic Kos Plateau Tuff (KPT) deposits (160 ky, South Aegean Arc, Greece), and combined anisotropy and (geometrical) tortuosity measurements of these scans with permeability data to gain insights into the development of pathways through magmatic foam and how it affects syn-eruptive degassing. The rhyolitic KPT pumices are particularly prone to textural analysis because (1) the deposits are non-welded, (2) the high viscosity of the magma helped preserving information on the state of the magmatic foam in the conduit immediately prior to fragmentation (i.e., disruption of magma into pyroclastic fragments) and (3) pumices display variable macroscopic textures including tubular and near-spherical networks of bubbles. The stacks of grey-scale μCT images were cropped and segmented to obtain 3D binary volumes. These volumes were submitted to anisotropy and tortuosity measurements using existing softwares. Results suggest a significantly more convoluted path through the spherical bubble networks than the tubular bubble networks. To complement this geometrical characterisation of pumices, permeability values on the same binary volumes will be acquired using two numerical codes (one is based on a Finite Difference scheme, the other using the Lattice Boltzmann technique).

  3. Measurement of the {sup 157}Gd(n,{gamma}) reaction with the DANCE {gamma} calorimeter array

    SciTech Connect

    Chyzh, A.; Dashdorj, D.; Baramsai, B.; Mitchell, G. E.; Walker, C. L.; Becker, J. A.; Parker, W.; Wu, C. Y.; Becvar, F.; Kroll, J.; Krticka, M.; Bredeweg, T. A.; Couture, A.; Haight, R. C.; Jandel, M.; O'Donnell, J. M.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wilhelmy, J. B.

    2011-07-15

    The {sup 157}Gd(n,{gamma}) reaction was measured with the DANCE {gamma} calorimeter (consisting of 160 BaF{sub 2} scintillation detectors) at the Los Alamos Neutron Science Center. The multiplicity distributions of the {gamma} decay were used to determine the resonance spins up to E{sub n}=300 eV. The {gamma}-ray energy spectra for different multiplicities were measured for the s-wave resonances. The shapes of these spectra were compared with simulations based on the use of the DICEBOX statistical model code. Simulations showed that the scissors mode is required not only for the ground-state transitions but also for transitions between excited states.

  4. Application of Brillouin scattering to the local anisotropy and birefringence measurements of thin layers.

    PubMed

    Matsukawa, Mami; Shintani, Kazuaki; Tomohiro, Shin-ichi; Ohtori, Norikazu

    2006-12-22

    Brillouin scattering is an efficient nondestructive and noncontact measurement method to obtain the wave properties of thin layers at hypersonic frequencies. The reflection induced ThetaA (RIThetaA) scattering geometry enables the simultaneous measurement of the phonons, which propagate in each direction of wave vectors of q(Theta A) (propagation in the film plane) and q(180) (back scattering). Using this scattering geometry, we could observe the refractive indices and birefringence of the piezoelectric poly-vinylidene fluoride (PVDF) film as a function of temperature. By introducing the microscopic technique, the elastic anisotropy and refractive index measurements in the minute area of polycrystalline ZnO films were also performed. PMID:16814836

  5. Seismic Anisotropy beneath the African Plate using Shear Wave Splitting Measurements from AfricaArray Stations

    NASA Astrophysics Data System (ADS)

    Nunley, M. E.; Weeraratne, D.; Nyblade, A.

    2011-12-01

    The African continental plate is made up of a series of cratons and fold belts with activation ages ranging from present to Archean. Recent studies have shown that this tectonic assemblage occurred over a long history of accretion and rifting cycles that likely left behind the complex crust and lithospheric fabric that we see today. Here we study seismic anisotropy beneath the African continent using a large array of permanent AfricaArray and Global Seismic Network seismic stations located throughout Africa. We supply shear wave splitting techniques to teleseismic earthquake events using the eigenvalue method where the second eigenvalue is minimized to determine anisotropy. Stations located in the Ethiopian rift zone yield a NE-SW fast direction with the largest delay times of 1.5s. One station (KOWA) located in the west African craton displays a NW-SE fast direction. Stations located near Cameroon, at the coastal edge of the central African shear zone, produce NW-SE fast directions oriented perpendicular to the shear zone axis. . A group of stations located on Archean crust in central Africa skirt the Congo craton and display consistent NNE fast directions and delay times of 1.0s. Two stations, LSZ and TEZI are located in the Damara suture belt between the Congo and Kaapvaal cratons display a NE-SW fast direction parallel to the suture axis. In the Kaapvaal craton region the average anisotropic direction is NNE with a 1.0s delay time. New stations available south of the Kaapvaal craton reveal a NE fast direction with delay times that vary from 0.5 to 1.3 s. Several splitting measurements are made for the southern station HVD which display backazimuth dependence producing NW-SE fast directions for ray paths coming from the east and are consistent with observations at GRM located east of HVD. These results show that seismic anisotropy across the continent is not uniform and shows significant variation between tectonic regions. While mantle flow and lithospheric

  6. A new measurement of the rare decay eta -> pi^0 gamma gamma with the Crystal Ball/TAPS detectors at the Mainz Microtron

    SciTech Connect

    Nefkens, B M; Prakhov, S; Aguar-Bartolom��, P; Annand, J R; Arends, H J; Bantawa, K; Beck, R; Bekrenev, V; Bergh��user, H; Braghieri, A; Briscoe, W J; Brudvik, J; Cherepnya, S; Codling, R F; Collicott, C; Costanza, S; Danilkin, I V; Denig, A; Demissie, B; Dieterle, M; Downie, E J; Drexler, P; Fil'kov, L V; Fix, A; Garni, S; Glazier, D I; Gregor, R; Hamilton, D; Heid, E; Hornidge, D; Howdle, D; Jahn, O; Jude, T C; Kashevarov, V L; K��ser, A; Keshelashvili, I; Kondratiev, R; Korolija, M; Kotulla, M; Koulbardis, A; Kruglov, S; Krusche, B; Lisin, V; Livingston, K; MacGregor, I J; Maghrbi, Y; Mancel, J; Manley, D M; McNicoll, E F; Mekterovic, D; Metag, V; Mushkarenkov, A; Nikolaev, A; Novotny, R; Oberle, M; Ortega, H; Ostrick, M; Ott, P; Otte, P B; Oussena, B; Pedroni, P; Polonski, A; Robinson, J; Rosner, G; Rostomyan, T; Schumann, S; Sikora, M H; Starostin, A; Strakovsky, I I; Strub, T; Suarez, I M; Supek, I; Tarbert, C M; Thiel, M; Thomas, A; Unverzagt, M; Watts, D P; Werthmueller, D; Witthauer, L

    2014-08-01

    A new measurement of the rare, doubly radiative decay eta->pi^0 gamma gamma was conducted with the Crystal Ball and TAPS multiphoton spectrometers together with the photon tagging facility at the Mainz Microtron MAMI. New data on the dependence of the partial decay width, Gamma(eta->pi^0 gamma gamma), on the two-photon invariant mass squared, m^2(gamma gamma), as well as a new, more precise value for the decay width, Gamma(eta->pi^0 gamma gamma) = (0.33+/-0.03_tot) eV, are based on analysis of 1.2 x 10^3 eta->pi^0 gamma gamma decays from a total of 6 x 10^7 eta mesons produced in the gamma p -> eta p reaction. The present results for dGamma(eta->pi^0 gamma gamma)/dm^2(gamma gamma) are in good agreement with previous measurements and recent theoretical calculations for this dependence.

  7. Measurement of the large-scale anisotropy of the cosmic background radiation at 3mm

    SciTech Connect

    Epstein, G.L.

    1983-12-01

    A balloon-borne differential radiometer has measured the large-scale anisotropy of the cosmic background radiation (CBR) with high sensitivity. The antenna temperature dipole anistropy at 90 GHz (3 mm wavelength) is 2.82 +- 0.19 mK, corresponding to a thermodynamic anistropy of 3.48 +- mK for a 2.7 K blackbody CBR. The dipole direction, 11.3 +- 0.1 hours right ascension and -5.7/sup 0/ +- 1.8/sup 0/ declination, agrees well with measurements at other frequencies. Calibration error dominates magnitude uncertainty, with statistical errors on dipole terms being under 0.1 mK. No significant quadrupole power is found, placing a 90% confidence-level upper limit of 0.27 mK on the RMS thermodynamic quadrupolar anistropy. 22 figures, 17 tables.

  8. High-resolution refractive index anisotropy measurement in optical fibers through phase retardation modulation

    NASA Astrophysics Data System (ADS)

    Sévigny, Benoit; Busque, François; Godbout, Nicolas; Lacroix, Suzanne; Faucher, Mathieu

    2008-03-01

    We present an improved, high-resolution method for the measurement of phase retardation induced by the material birefringence of optical fibers. Such a method can be used to retrieve information about the spatial distribution of refractive index anisotropy in the fiber by comparing the accumulated phase of a polarization component oriented along the fiber transmission axis and another located in the transverse plane. The method is based on the nonlinear regression of a phase modulated signal of known modulation amplitude altered by the sample. Experimental results obtained with our method for a standard telecommunications fiber (the Corning SMF-28) as well as photosensitive fibers (Fibercore PS1250 and PS1500) are presented with a noise-limited phase resolution below 10-4 radians and a spatial resolution below 1 μm. An analysis of the limitation of such measurement methods is also presented including diffraction by the fibers.

  9. Spreadsheet analysis of gamma spectra for nuclear material measurements

    SciTech Connect

    Mosby, W.R.; Pace, D.M.

    1990-01-01

    A widely available commercial spreadsheet package for personal computers is used to calculate gamma spectra peak areas using both region of interest and peak fitting methods. The gamma peak areas obtained are used for uranium enrichment assays and for isotopic analyses of mixtures of transuranics. The use of spreadsheet software with an internal processing language allows automation of routine analysis procedures increasing ease of use and reducing processing errors while providing great flexibility in addressing unusual measurement problems. 4 refs., 9 figs.

  10. Earth formation density measurement from natural gamma ray spectral logs

    SciTech Connect

    Smith Jr., H. D.

    1985-07-02

    Naturally occurring gamma radiations from earth formations in the vicinity of a well borehole are detected and spectrally separated into six energy regions or bands. Borehole compensation techniques are applied to the gamma ray spectra and the attenuation coefficient /eta/ is determined as a result thereof. The attenuation coefficient is used along with predetermined borehole, casing and cement parameters to derive a measure of the density of the earth formations.

  11. Precision Measurement of {eta} --> {gamma} {gamma} Decay Width via the Primakoff Effect

    SciTech Connect

    Gan, Liping Gin

    2013-08-01

    A precision measurement of the {eta} --> {gamma} {gamma} decay width via the Primakoff effect is underway in Hall D at Jefferson Lab. The decay width will be extracted from measured differential cross sections at forward angles on two light targets, liquid hydrogen and 4He, using a 11.5 GeV tagged photon beam. Results of this experiment will not only potentially resolve a long standing discrepancy between the Primakoff and the collider measurements, but will also reduce the experimental uncertainty by a factor of two on the average value of previous experimental results listed by the Particle Data Group(PDG). It will directly improve all other eta partial decay widths which rely on the accuracy of the eta radiative decay width. The projected 3% precision on the {Gamma}({eta} --> {gamma} {gamma} ) measurement will have a significant impact on the experimental determination of the fundamental parameters in QCD, such as the ratio of light quark masses (m{sub u},m{sub d},m{sub s}) and the {eta} - {eta}' mixing angle. It will be a sensitive probe for understanding QCD symmetries and the origin and the dynamics of QCD symmetry breaking.

  12. Moisture effect in prompt gamma measurements from soil samples.

    PubMed

    Naqvi, A A; Khiari, F Z; Liadi, F A; Khateeb-Ur-Rehman; Raashid, M A; Isab, A H

    2016-09-01

    The variation in intensity of 1.78MeV silicon, 6.13MeV oxygen, and 2.22MeV hydrogen prompt gamma rays from soil samples due to the addition of 5.1, 7.4, 9.7, 11.9 and 14.0wt% water was studied for 14MeV incident neutron beams utilizing a LaBr3:Ce gamma ray detector. The intensities of 1.78MeV and 6.13MeV gamma rays from silicon and oxygen, respectively, decreased with increasing sample moisture. The intensity of 2.22MeV hydrogen gamma rays increases with moisture. The decrease in intensity of silicon and oxygen gamma rays with moisture concentration indicates a loss of 14MeV neutron flux, while the increase in intensity of 2.22MeV gamma rays with moisture indicates an increase in thermal neutron flux due to increasing concentration of moisture. The experimental intensities of silicon, oxygen and hydrogen prompt gamma rays, measured as a function of moisture concentration in the soil samples, are in good agreement with the theoretical results obtained through Monte Carlo calculations. PMID:27337651

  13. Gamma densitometry for the measurement of skeletal density

    NASA Astrophysics Data System (ADS)

    Chalker, B. E.; Barnes, D. J.

    1990-03-01

    A method is described for the measurement of the density of calcium carbonate materials from the attenuation of a narrow, collimated beam of gamma photons. For the measurement of density for slices, approximately 0.5 to 1.0 cm thick, from the skeletons of reef building corals, the optimum beam energy is 30 34 keV; and measurement is practical from approximately 22 to 100 keV. The potential utilities of five commercially available isotopic sources (109Cd,125I,253Gd,210Pb and241Am) are evaluated. Methods and results are presented for gamma densitometry using210Pb and241Am. The210Pb point source had its principal gamma emission at 46.5 keV. Bremsstrahlung and high energy (800 keV) gamma emissions associated with the210Pb decay grand-daughter were detected, and procedures were developed to accommodate the contribution of these emissions to the overall count rate. The attenuation of count rate by aluminium and aragonite absorbers closely followed simple theoretical considerations provided that narrow energy window settings were used at the radiation monitor. These theoretical considerations take account of the density of the material absorbing the radiation, and hence the density could be determined from the attenuation of the gamma beam. Increased accuracy was achieved by the use of241Am and high speed counting equipment.241Am has its principal gamma emission at 59.6 keV. The attenuation of this gamma beam follows simple theoretical considerations for targets with mass thicknesses from 0 to 6 g cm-2. Aragonite from the shell of a giant clam was found to have slightly different properties in the absorption of gamma photons to aragonite from a coral skeleton. The differences were small but statistically significant.

  14. Application of Bayesian decision theory to airborne gamma snow measurement

    NASA Technical Reports Server (NTRS)

    Bissell, V. C.

    1975-01-01

    Measured values of several variables are incorporated into the calculation of snow water equivalent as measured from an aircraft by snow attenuation of terrestrial gamma radiation. Bayesian decision theory provides a snow water equivalent measurement by taking into account the uncertainties in the individual measurement variables and filtering information about the measurement variables through prior notions of what the calculated variable (water equivalent) should be.

  15. Influence of the anisotropy on the ``SAMR'' method for measuring magnetostriction in amorphous ribbons

    NASA Astrophysics Data System (ADS)

    Hernando, A.; Vázquez, M.; Madurga, V.; Ascasibar, E.; Liniers, M.

    1986-09-01

    The small angle magnetization rotation (SAMR) method has been found to be quite convinient for measuring magnetostriction in metallic glasses with low magnetostriction. Nevertheless the method fails in some sense when applied to high magnetostrictive samples. The origin of such failure has been analysed. The method becomes reliable when the sample saturates under the action of the axial field H z. On the other hand the sensitivity decreases with H2z. Since the internal str esses are the main source of anisotropy, via magnetoelastic coupling, the higher magnetostriction is, the stronger H z, required for saturating, becomes. Therefore the sensitivity of the method drops with the square of the magnetostriction of the sample. Some experiments confirming this explanation are shown.

  16. Stress anisotropy and concentration effects in high pressure measurements. [sodium chloride

    NASA Technical Reports Server (NTRS)

    Nelson, D. A., Jr.; Ruoff, A. L.

    1974-01-01

    Sodium chloride is used as an internal pressure standard in high pressure research. Possible corrections are discussed which are needed in the calibration of this standard due to the independent effects of stress anisotropy and stress concentration in pressure vessels. The first is due to the lack of a truly hydrostatic state of stress in solid state pressure vessels. The second is due to the difference in the compressibilities between the pressure transmitting substances (sodium chloride) and a stiffer test specimen. These two corrections are then combined and a total correction, as a function of measured pressure, is discussed for two systems presently in use. The predicted value of the combined effect is about 5-10% of the pressure at 30 GPa.

  17. Measurement of background gamma radiation in the northern Marshall Islands

    PubMed Central

    Bordner, Autumn S.; Crosswell, Danielle A.; Katz, Ainsley O.; Shah, Jill T.; Zhang, Catherine R.; Nikolic-Hughes, Ivana; Hughes, Emlyn W.; Ruderman, Malvin A.

    2016-01-01

    We report measurements of background gamma radiation levels on six islands in the northern Marshall Islands (Enewetak, Medren, and Runit onEnewetak Atoll; Bikini and Nam on Bikini Atoll; and Rongelap on Rongelap Atoll). Measurable excess radiation could be expected from the decay of 137Cs produced by the US nuclear testing program there from 1946 to 1958. These recordings are of relevance to safety of human habitation and resettlement. We find low levels of gamma radiation for the settled island of Enewetak [mean = 7.6 millirem/year (mrem/y) = 0.076 millisievert/year (mSv/y)], larger levels of gamma radiation for the island of Rongelap (mean = 19.8 mrem/y = 0.198 mSv/y), and relatively high gamma radiation on the island of Bikini (mean = 184 mrem/y = 1.84 mSv/y). Distributions of gamma radiation levels are provided, and hot spots are discussed. We provide interpolated maps for four islands (Enewetak, Medren, Bikini, and Rongelap), and make comparisons to control measurements performed on the island of Majuro in the southern Marshall Islands, measurements made in Central Park in New York City, and the standard agreed upon by the United States and the Republic of the Marshall Islands (RMI) governments (100 mrem/y = 1 mSv/y). External gamma radiation levels on Bikini Island significantly exceed this standard (P = <<0.01), and external gamma radiation levels on the other islands are below the standard. To determine conclusively whether these islands are safe for habitation, radiation exposure through additional pathways such as food ingestion must be considered. PMID:27274073

  18. Measurement of background gamma radiation in the northern Marshall Islands.

    PubMed

    Bordner, Autumn S; Crosswell, Danielle A; Katz, Ainsley O; Shah, Jill T; Zhang, Catherine R; Nikolic-Hughes, Ivana; Hughes, Emlyn W; Ruderman, Malvin A

    2016-06-21

    We report measurements of background gamma radiation levels on six islands in the northern Marshall Islands (Enewetak, Medren, and Runit onEnewetak Atoll; Bikini and Nam on Bikini Atoll; and Rongelap on Rongelap Atoll). Measurable excess radiation could be expected from the decay of (137)Cs produced by the US nuclear testing program there from 1946 to 1958. These recordings are of relevance to safety of human habitation and resettlement. We find low levels of gamma radiation for the settled island of Enewetak [mean = 7.6 millirem/year (mrem/y) = 0.076 millisievert/year (mSv/y)], larger levels of gamma radiation for the island of Rongelap (mean = 19.8 mrem/y = 0.198 mSv/y), and relatively high gamma radiation on the island of Bikini (mean = 184 mrem/y = 1.84 mSv/y). Distributions of gamma radiation levels are provided, and hot spots are discussed. We provide interpolated maps for four islands (Enewetak, Medren, Bikini, and Rongelap), and make comparisons to control measurements performed on the island of Majuro in the southern Marshall Islands, measurements made in Central Park in New York City, and the standard agreed upon by the United States and the Republic of the Marshall Islands (RMI) governments (100 mrem/y = 1 mSv/y). External gamma radiation levels on Bikini Island significantly exceed this standard (P = <0.01), and external gamma radiation levels on the other islands are below the standard. To determine conclusively whether these islands are safe for habitation, radiation exposure through additional pathways such as food ingestion must be considered. PMID:27274073

  19. Measurement of B decays to phi K gamma

    SciTech Connect

    Aubert, B.

    2006-07-28

    We measure the branching fraction of the radiative B{sup -} decay {Beta}(B{sup -} {yields} {phi}K{sup -}{gamma}) = (3.46 {+-} 0.57{sub -0.37}{sup +0.39}) x 10{sup -6}, and set an upper limit on the radiative {bar B}{sup 0} decay {Beta}({bar B}{sup 0} {yields} {phi}{bar K}{sup 0}{gamma}) < 2.71 x 10{sup -6} at 90% confidence level. We also measure the direct CP asymmetry of the B{sup -} {yields} {phi}K{sup -}{gamma} mode {Alpha}{sub CP} = (-26.4 {+-} 14.3 {+-} 4.8)%. The uncertainties are statistical and systematic, respectively. These measurements are based on 207 fb{sup -1} of data collected at the {Upsilon}(4S) resonance with the BABAR detector.

  20. Gamma densitometer for measuring Pu density in fuel tubes

    SciTech Connect

    Winn, W.G.

    1982-01-01

    A fuel-gamma-densitometer (FGD) has been developed to examine nondestructively the uniformity of plutonium in aluminum-clad fuel tubes at the Savannah River Plant (SRP). The monitoring technique is ..gamma..-ray spectroscopy with a lead-collimated Ge(Li) detector. Plutonium density is correlated with the measured intensity of the 208 keV ..gamma..-ray from /sup 237/U (7d) of the /sup 241/Pu (15y) decay chain. The FGD measures the plutonium density within 0.125- or 0.25-inch-diameter areas of the 0.133- to 0.183-inch-thick tube walls. Each measurement yields a density ratio that relates the plutonium density of the measured area to the plutonium density in normal regions of the tube. The technique was used to appraise a series of fuel tubes to be irradated in an SRP reactor. High-density plutonium areas were initially identified by x-ray methods and then examined quantitatively with the FGD. The FGD reliably tested fuel tubes and yielded density ratios over a range of 0.0 to 2.5. FGD measurements examined (1) nonuniform plutonium densities or hot spots, (2) uniform high-density patches, and (3) plutonium density distribution in thin cladding regions. Measurements for tubes with known plutonium density agreed with predictions to within 2%. Attenuation measurements of the 208-keV ..gamma..-ray passage through the tube walls agreed to within 2 to 3% of calculated predictions. Collimator leakage measurements agreed with model calculations that predicted less than a 1.5% effect on plutonium density ratios. Finally, FGD measurements correlated well with x-ray transmission and fluoroscopic measurements. The data analysis for density ratios involved a small correction of about 10% for ..gamma..-shielding within the fuel tube. For hot spot examinations, limited information for this correction dictated a density ratio uncertainty of 3 to 5%.

  1. A COMPARISON OF GADRAS SIMULATED AND MEASURED GAMMA RAY SPECTRA

    SciTech Connect

    Jeffcoat, R.; Salaymeh, S.

    2010-06-28

    Gamma-ray radiation detection systems are continuously being developed and improved for detecting the presence of radioactive material and for identifying isotopes present. Gamma-ray spectra, from many different isotopes and in different types and thicknesses of attenuation material and matrixes, are needed to evaluate the performance of these devices. Recently, a test and evaluation exercise was performed by the Savannah River National Laboratory that required a large number of gamma-ray spectra. Simulated spectra were used for a major portion of the testing in order to provide a pool of data large enough for the results to be statistically significant. The test data set was comprised of two types of data, measured and simulated. The measured data were acquired with a hand-held Radioisotope Identification Device (RIID) and simulated spectra were created using Gamma Detector Response and Analysis Software (GADRAS, Mitchell and Mattingly, Sandia National Laboratory). GADRAS uses a one-dimensional discrete ordinate calculation to simulate gamma-ray spectra. The measured and simulated spectra have been analyzed and compared. This paper will discuss the results of the comparison and offer explanations for spectral differences.

  2. Nondestructive evaluation of residual stresses in case hardened steels by magnetic anisotropy measurements

    NASA Astrophysics Data System (ADS)

    Lo, C. C. H.

    2012-05-01

    This paper reports on a recent study aimed at developing the stress-induced magnetic anisotropy (SMA) technique for characterizing residual stresses in case hardened steel components. The results of SMA measurements performed on flat induction hardened steel discs with different case depths confirm the feasibility of detecting principal stress axes by measuring the angular variation of magnetic permeability. The permeability signals along the principal axes were found to vary monotonically with the residual stresses measured by XRD, but the signals are in general smaller for samples with a larger case depth. The magnetomechanical properties of the martensitic case and ferritic/pearlitic core of the induction hardened sample were studied by measuring magnetostriction curves from strip samples that were cut from the case and core regions, respectively. The case strip shows a significantly lower magnetostriction than the core strip, indicating a weaker stress dependence of magnetic properties for the martensitic case than for the ferritic/pearlitic bulk of the case hardened samples.

  3. Measurement and analysis of quadruple ({alpha}{gamma}{gamma}) angular correlations for high spin states of {sup 24}Mg.

    SciTech Connect

    Wiedenhover, I.; Wuosmaa, A. H.; Lister, C. J.; Carpenter, M. P.; Janssens, R. V. F.; Amro, H.; Caggiano, J.; Heinz, A.; Kondev, F. G.; Lauritsen, T.; Siem, S.; Sonzogni, A.; Bhattacharyya, P.; Devlin, M.; Sarantites, D. G.; Sobotka, L. G.

    2000-10-30

    The high-lying, {alpha}-decaying states in {sup 24}Mg have been studied by measuring the complete decay path of {alpha} and {gamma} emissions using five segmented Silicon detectors in conjunction with GAMMASPHERE. The authors analyzed the ({alpha}{gamma}) triple angular correlations and, for the first time, ({alpha}{gamma}{gamma}) quadruple correlations. The data analysis is based on a new Fourier transformation technique. The power of the technique is demonstrated.

  4. Measurement of anisotropy in the arrival direction distribution of PeV cosmic rays with IceTop

    NASA Astrophysics Data System (ADS)

    Westerhoff, Stefan; IceCube Collaboration

    2012-12-01

    We report on the observation of anisotropy in the arrival direction distribution of cosmic rays at PeV energies in the southern hemisphere. The analysis is based on data taken between 2009 and 2012 with the IceTop air shower array at the South Pole. We study two different energy bands with median energies of 400 TeV and 2 PeV, respectively. In both bands, we observe a strong deficit with an angular size of about 30°. The anisotropy at 400 TeV is consistent with previously reported results from cosmic-ray measurements with IceCube in the same energy range. IceTop data reveal that the anisotropy persists to at least 2 PeV.

  5. Aether drift and the isotropy of the universe: a measurement of anisotropies in the primordial black-body radiation

    NASA Technical Reports Server (NTRS)

    Muller, R. A.

    1979-01-01

    This experiment detected and mapped large-angular-scale anisotropies in the 3 K primordial black-body radiation with a sensitivity of 2x.0001k and an angular resolution of about 10 degs. It measured the motion of the Earth with respect to the distant matter of the Universe (Aether Drift), and probed the homogeneity and isotropy of the Universe (the Cosmological Principle). The experiment used two Dicke radiometers, one at 33 GHz to detect the cosmic anisotropy, and one at 54 GHz to detect anisotropies in the residual oxygen above the detectors. The system was installed in the NASA-Ames Earth Survey Aircraft (U-2), and operated successfully in a series of flights.

  6. On the Anisotropy of Perceived Ground Extents and the Interpretation of Walked Distance as a Measure of Perception

    ERIC Educational Resources Information Center

    Li, Zhi; Sun, Emily; Strawser, Cassandra J.; Spiegel, Ariana; Klein, Brennan; Durgin, Frank H.

    2013-01-01

    Two experiments are reported concerning the perception of ground extent to discover whether prior reports of anisotropy between frontal extents and extents in depth were consistent across different measures (visual matching and pantomime walking) and test environments (outdoor environments and virtual environments). In Experiment 1 it was found…

  7. Spectrum and Anisotropy of Turbulence from Multi-frequency Measurement of Synchrotron Polarization

    NASA Astrophysics Data System (ADS)

    Lazarian, A.; Pogosyan, D.

    2016-02-01

    We consider turbulent synchrotron-emitting media that also exhibit Faraday rotation and provide a statistical description of synchrotron polarization fluctuations. In particular, we consider these fluctuations as a function of the spatial separation of the direction of the measurements and as a function of wavelength for the same line of sight. On the basis of our general analytical approach, we introduce several measures that can be used to obtain the spectral slopes and correlation scales of both the underlying magnetic turbulence responsible for emission and the spectrum of the Faraday rotation fluctuations. We show the synergetic nature of these measures and discuss how the study can be performed using sparsely sampled interferometric data. We also discuss how additional characteristics of turbulence can be obtained, including the turbulence anisotropy and the three-dimensional direction of the mean magnetic field. In addition, we consider the cases when the synchrotron emission and Faraday rotation regions are spatially separated. Appealing to our earlier study, we explain that our new results are applicable to a wide range of spectral indexes of relativistic electrons responsible for synchrotron emission. We expect wide application of our techniques, both with existing synchrotron data sets and with big forthcoming data sets from LOFAR and SKA.

  8. Constraints on the Nature of the Lithosphere-Asthenosphere Boundary: Comparison of Observed Textural Evolution to Measured Seismic Anisotropy

    NASA Astrophysics Data System (ADS)

    Hansen, L. N.; Qi, C.; Kumamoto, K.; Warren, J. M.; Katz, R. F.; Kohlstedt, D. L.

    2014-12-01

    The nature of the lithosphere-asthenosphere boundary (LAB) determines the mechanical and compositional coupling between rigid plates and underlying convecting mantle. Seismological studies reveal distinct reflectors in the uppermost oceanic mantle that are sometimes interpreted as the LAB. These reflectors roughly correlate with the location of vertical gradients in radial seismic anisotropy. However, these proxies for the LAB 1) do not exhibit the depth-age relationship predicted by thermal models and 2) are not detected consistently throughout the major ocean basins. In contrast, gradients in azimuthal anisotropy in oceanic upper mantle do appear to coincide with the predicted thermal structure. This overall seismic signature is suggested to arise both from melt-related processes at mid-ocean ridges and from "freezing in" anisotropy during changes in the direction of plate motion. We test recent interpretations of this upper-mantle seismic structure with measurements of crystallographic textures in experimentally and naturally deformed peridotites. Key observations: 1) Experimental deformation of nominally melt-free olivine aggregates reveals a protracted increase in texture strength and, therefore, in magnitude of elastic anisotropy with progressive deformation, 2) melt-rich systems attain a steady state at very low strain (<~1) with fast seismic directions normal to those in the melt-free case, and 3) textures measured in samples from peridotite massifs exhibit a cm- to m-scale compositional heterogeneity associated with melt production and extraction that could be a significant source of radial anisotropy. In conjunction with constraints on finite strain and melting extent from geodynamic simulations, we use textural observations to predict seismic structure in an oceanic setting. Comparison of our predictions to observed seismic anisotropy provide insight into the role of composition, melting, and rheology in defining the LAB.

  9. Measurement of Gamma Energy Distributions and Multiplicities Using STEFF

    NASA Astrophysics Data System (ADS)

    Murray, E.; Smith, A. G.; Pollitt, A. J.; Matarranz, J.; Tsekhanovich, I.; Soldner, T.; Koster, U.; Biswas, D. C.

    2014-05-01

    Prompt gamma-ray energy distributions and multiplicities released during thermally induced fission of 235U have been measured using STEFF (SpecTrometer for Exotic Fission Fragments). Thermal neutrons are provided by the high-flux reactor at the ILL, Grenoble. STEFF is a unique 2E2v device that uses a coincidence timing method to measure the emission of prompt gamma rays as a function of the fragment mass and energy. Following scission, the fission fragments contain excitation energy that is released via prompt neutron and gamma-ray emission as the fragment decays to the ground state. STEFF contains an array of 11 NaI detectors surrounding the uranium target providing a 6.8% photopeak detection efficiency for gamma rays released within 1 ns of the scission time. STEFF also consists of 7 NE213 detectors, which detect the emission of prompt neutrons, the release of which is associated with reduction of fragment energy and, to a lesser extent, fragment spin. This experiment acts as a direct response to the NEA high priority demand which requires more accurate knowledge of heating caused by gamma emission in the next generation of nuclear reactors.

  10. Determination of elastic anisotropy of rocks from P- and S-wave velocities: numerical modelling and lab measurements

    NASA Astrophysics Data System (ADS)

    Svitek, Tomáš; Vavryčuk, Václav; Lokajíček, Tomáš; Petružálek, Matěj

    2014-12-01

    The most common type of waves used for probing anisotropy of rocks in laboratory is the direct P wave. Information potential of the measured P-wave velocity, however, is limited. In rocks displaying weak triclinic anisotropy, the P-wave velocity depends just on 15 linear combinations of 21 elastic parameters, called the weak-anisotropy parameters. In strong triclinic anisotropy, the P-wave velocity depends on the whole set of 21 elastic parameters, but inversion for six of them is ill-conditioned and these parameters are retrieved with a low accuracy. Therefore, in order to retrieve the complete elastic tensor accurately, velocities of S waves must also be measured and inverted. For this purpose, we developed a lab facility which allows the P- and S-wave ultrasonic sounding of spherical rock samples in 132 directions distributed regularly over the sphere. The velocities are measured using a pair of P-wave sensors with the transmitter and receiver polarized along the radial direction and using two pairs of S-wave sensors with the transmitter and receiver polarized tangentially to the spherical sample in mutually perpendicular directions. We present inversion methods of phase and ray velocities for elastic parameters describing general triclinic anisotropy. We demonstrate on synthetic tests that the inversion becomes more robust and stable if the S-wave velocities are included. This applies even to the case when the velocity of the S waves is measured in a limited number of directions and with a significantly lower accuracy than that of the P wave. Finally, we analyse velocities measured on a rock sample from the Outokumpu deep drill hole, Finland. We present complete sets of elastic parameters of the sample including the error analysis for several levels of confining pressure ranging from 0.1 to 70 MPa.

  11. Systematic Effects on Duration Measurements of Gamma-Ray Bursts

    NASA Technical Reports Server (NTRS)

    Koshut, Thomas M.; Paciesas, William S.; Kouveliotou, Chryssa; vanParadijs, Jan; Pendleton, Geoffrey N.; Fishman, Gerald J.; Meegan, Charles A.

    1996-01-01

    The parameters T(sub 90) and T(sub 50) have recently been introduced as a measurement of the duration of gamma-ray bursts. We present here a description of the method of measuring T(sub 90) and T(sub 50) and its application to gamma-ray bursts observed with the Burst and Transient Source Experiment (BATSE) onboard the Compton Gamma-Ray Observatory (CGRO). We use simulated as well as observed time profiles to address some of the possible systematic effects affecting individual T(sub 90) (T(sub 50)) measurements. We show that these systematic effects do not mimic those effects that would result from time dilation if the burst sources are at distances of several Gpc. We discuss the impact of these systematic effects on the T(sub 90) (T(sub 50)) distributions for the gamma-ray bursts observed with BATSE. We distinguish between various types of T(sub 90) (T(sub 50)) distributions, and discuss the ways in which distributions observed with different experiments can vary, even though the measurements for commonly observed bursts may be the same. We then discuss the distributions observed with BATSE and compare them to those observed with other experiments.

  12. Measurements of B to V(Gamma) Decays

    SciTech Connect

    Yarritu, Aaron K.; /Stanford U., Phys. Dept.

    2010-09-02

    The standard model has been highly successful at describing current experimental data. However, extensions of the standard model predict particles that have masses at energy scales that are above the electroweak scale. The flavor-changing neutral current processes of the B meson are sensitive to the influences of these new physics contributions. These processes proceed through loop diagrams, thus allowing new physics to enter at the same order as the standard model. New physics may contribute to the enhancement or suppression of rate asymmetries or the decay rates of these processes. The transition B {yields} V{gamma} (V = K*(892), {rho}(770), {omega}(782), {phi}(1020)) represents radiative decays of the B meson that proceed through penguin processes. Hadronic uncertainties limit the theoretical accuracy of the prediction of the branching fractions. However, uncertainties, both theoretical and experimental, are much reduced when considering quantities involving ratios of branching fractions, such as CP or isospin asymmetries. The most dominant exclusive radiative b {yields} s transition is B {yields} K*{gamma}. We present the best measurements of the branching fractions, direct CP, and isospin asymmetries of B {yields} K*{gamma}. The analogous b {yields} d transitions are B {yields} {rho}{gamma} and B {yields} {omega}{gamma}, which are suppressed by a factor of |V{sub td}/V{sub ts}|{sup 2} {approx} 0.04 relative to B {yields} K*{gamma}. A measurement of the branching fractions and isospin asymmetry of B{sup +} {yields} {rho}{sup +}{gamma} and B{sup 0} {yields} {rho}{sup 0}{gamma}, as well as a search for B {yields} {omega}{gamma}, are also given. These measurements are combined to calculate the ratio of CKM matrix elements |V{sub td}/V{sub ts}|, which corresponds to the length of one side of the unitary triangle. Finally, we present a search for the penguin annihilation process B {yields}{phi}{gamma}. We use a sample of 383 million B{bar B} events collected with

  13. Elastic anisotropy, crystallographic orientation and texture measurement by photothermal interferometric microscopy

    NASA Astrophysics Data System (ADS)

    Jumel, J.; Rochais, D.; Lepoutre, F.

    2005-06-01

    Photothermal interferometric microscopy is used to determine the thermal diffusivity, elastic anisotropy and principal axis orientation of nickel superalloy single crystal samples. The inversion method is explained in details.

  14. Directional correlation measurements for gamma transitions in /sup 127/Te

    SciTech Connect

    de Souza, M.O.M.D.; Saxena, R.N.

    1985-02-01

    The directional correlation of coincident ..gamma.. transitions in /sup 127/Te has been measured following the ..beta../sup -/ decay of /sup 127/Sb (T/sub 1/2/ = 3.9 d) using Ge(Li)-Ge(Li) and Ge(Li)-NaI(T1) gamma spectrometers. Measurements have been carried out for 14 gamma cascades resulting in the determination of multipole mixing ratios delta(E2/M1) for 15 ..gamma.. transitions. The present results permitted a definite spin assignment of (7/2) for the 785 keV level and confirmation of several previous assignments to other levels in /sup 127/Te. The g factor of the 340 keV ((9/2)/sup -/) level has also been measured using the integral perturbed angular correlation method in the hyperfine magnetic field of a Te in Ni matrix. The results of the g factor as well as the mixing ratio for the 252 keV ((9/2)/sup -/..-->..(11/2)/sup -/) transition support the earlier interpretation of this state as an anomalous coupling state.

  15. Gamma Ray Mirrors for Direct Measurement of Spent Nuclear Fuel

    SciTech Connect

    Pivovaroff, Dr. Michael J.; Ziock, Klaus-Peter; Harrison, Mark J; Soufli, Regina

    2014-01-01

    Direct measurement of the amount of Pu and U in spent nuclear fuel represents a challenge for the safeguards community. Ideally, the characteristic gamma-ray emission lines from different isotopes provide an observable suitable for this task. However, these lines are generally lost in the fierce flux of radiation emitted by the fuel. The rates are so high that detector dead times limit measurements to only very small solid angles of the fuel. Only through the use of carefully designed view ports and long dwell times are such measurements possible. Recent advances in multilayer grazing-incidence gamma-ray optics provide one possible means of overcoming this difficulty. With a proper optical and coating design, such optics can serve as a notch filter, passing only narrow regions of the overall spectrum to a fully shielded detector that does not view the spent fuel directly. We report on the design of a mirror system and a number of experimental measurements.

  16. Measurements of the CKM angle gamma at BaBar

    SciTech Connect

    Marchiori, G.; /Pisa U. /INFN, Pisa

    2011-11-07

    We report on our recent measurements of the Cabibbo-Kobayashi-Maskawa CP-violating phase {gamma} and of related CP-asymmetries and branching fraction ratios. The measurements have been performed on samples of up to 465 million B{bar B} pairs collected by the BABAR detector at the SLAC PEP-II asymmetric-energy B factory in the years 1999-2007.

  17. A portable absorbed dose measuring instrument with gamma discrimination

    NASA Technical Reports Server (NTRS)

    Quam, W. M.; Wilde, W. I.

    1972-01-01

    The characteristics of an electronic instrument for measuring the radiation dose absorbed by tissues are presented. The detector is a sphere of tissue-equivalent plastic with a single wire located on a diameter of the sphere. The electronic circuits and method of operation of the detector are described. Advantages are the small size and easy portability plus ability to selectively measure neutron and gamma plus neutron events.

  18. MAXIMA: an experiment to measure temperature anisotropy in the cosmic microwave background

    SciTech Connect

    Lee, A.T.; Balbi, A.; Borrill, J.; Jaffe, A.H.; Oh, S.; Rabii, B.; Richards, P.L.; Smoot, G.F.; Winant, C.D.; Lee, A.T.; Jaffe, A.H.; Rabii, B.; Richards, P.L.; Smoot, G.F.; Winant, C.D.; Ade, P.; Hristov, V.; Lange, A.E.; Pascale, E.; Balbi, A.; Borrill, J.; Bock, J.; Crill, B.P.; Smoot, G.F.; Bock, J.; Del Castillo, H.; Boscaleri, A.; De Bernardis, P.; Ferreira, P.; Ganga, K.; Hanany, S.; Mauskopf, P.; Netterfield, C.B.; Ruhl, J.

    1999-05-01

    We describe the MAXIMA experiment, a balloon-borne measurement designed to map temperature anisotropy in the Cosmic Microwave Background (CMB) from l=80 to l=800. The experiment consists of a 1.3 m diameter off-axis Gregorian telescope and a receiver with a 16 element array of bolometers cooled to 100 mK. The frequency bands are centered at 150, 240, and 410 GHz. The 10{sup {prime}} FWHM beam sizes are well matched to the scale of acoustic peaks expected in the angular power spectrum of the CMB. The first flight of the experiment in its full configuration was launched in August 1998. A 122 deg{sup 2} map of the sky was made near the Draco constellation during the 7 hour flight in a region of extremely low galactic dust contamination. This map covers 0.3{percent} of the sky and has 3200 independent beamsize pixels. We describe the MAXIMA instrument and its performance during the recent flight. {copyright} {ital 1999 American Institute of Physics.}

  19. The millimeter and submillimeter wavelength diffuse backgrounds: Measurements of the spectrum and anisotropy

    NASA Astrophysics Data System (ADS)

    Alsop, David Charles

    The results of two experiments to study the diffuse background at millimeter and submillimeter wavelengths are reported. The first experiment was a rocket-borne photometer designed to measure the spectrum of the background. The background was observed in six bands centered at 7, 13, 20, 30, 40, and 50 cm-1. After the flight, a systematic error was detected in the flight data. A model for the error was developed and an attempt at correction was made, but indications that the correction was not complete were found. The second experiment was a search for anisotropy in the Cosmic Microwave Background at one degree angular scales. The search employed a multiband, bolometric receiver mounted on a balloon-borne telescope. The search achieved the highest statistical sensitivity at this angular scale, which is of crucial importance for constraining theories of structure formation in the universe. Signals in excess of random were detected but concern over possible systematic error sources prevents the interpretation of the signals as uniquely cosmological in origin.

  20. Measurement of the gamma gamma* to eta_c transition form factor

    SciTech Connect

    Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M.; Palano, A.; Pappagallo, M.; Eigen, G.; Stugu, B.; Sun, L.; Battaglia, M.; Brown, D.N.; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Osipenkov, I.L.; Tanabe, T.; Hawkes, C.M.; /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Indian Inst. Tech., Guwahati /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /INFN, Naples /Naples U. /NIKHEF, Amsterdam /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas Nuclear Corp., Austin /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U. /Victoria U. /Warwick U. /Wisconsin U., Madison

    2010-04-28

    The authors study the reaction e{sup +}e{sup -} {yields} e{sup +}e{sup -} {eta}{sub c}, {eta}{sub c} {yields} K{sub S}K{sup {+-}}{pi}{sup {-+}} and obtain {eta}{sub c} mass and width values 2982.2 {+-} 0.4 {+-} 1.6 MeV/c{sup 2} and 31.7 {+-} 1.2 {+-} 0.8 MeV, respectively. They find {Lambda}({eta}{sub c} {yields} {gamma}{gamma}){Beta}({eta}{sub c} {yields} K{bar K}{pi}) = 0.374 {+-} 0.009 {+-} 0.031 keV, and measure the {gamma}{gamma}* {yields} {eta}{sub c} transition form factor in the momentum transfer range from 2 to 50 GeV{sup 2}. The analysis is based on 469 fb{sup -1} of integrated luminosity collected at PEP-II with the BABAR detector at e{sup +}e{sup -} center-of-mass energies near 10.6 GeV.

  1. Measurement of neutron and gamma radiation in a mixed field.

    PubMed

    Kronenberg, S; Bechtel, E; Brucker, G J

    1995-10-01

    This paper describes a study of dosimeters with a range of 0 to 0.2 mGy that were developed by the authors and built by the Federal Emergency Management Agency (FEMA). These instruments are a type of air-filled ion chamber that is self-reading by means of an internal carbon fiber electrometer. Two types of these dosimeters were constructed: one with an ion chamber wall made of a conductive hydrogenous material, and the other device made with a conductive wall lining of non-hydrogenous material. Both types of dosimeters have the same sensitivity for gamma radiation, but greatly different sensitivities for fast neutrons, thus making it possible to measure gamma radiation and neutron doses separately in a mixed radiation field. The results indicate that such pairs of dosimeters can be used for the first time to accurately monitor personnel for gamma ray and neutron doses in real time. Since the difference in neutron sensitivities is due to the properties of wall materials, periodic calibrations of the dosimeter system can be accomplished using only gamma rays after the material constants are measured. The absolute number of neutron induced transmutations in sulfur was required for this work. Methods and techniques which were applied to determine this quantity are described in the text. This approach was one of several dosimetric procedures utilized in this investigation. PMID:7558835

  2. Atmospheric measurements at Mars via gamma ray spectroscopy

    NASA Technical Reports Server (NTRS)

    Metzger, Albert E.; Haines, Eldon L.

    1990-01-01

    This paper describes three methods for measuring the Martian atmosphere using gamma ray spectroscopy. One method determines atmospheric thickness based on the energy-dependent differential attenuation of gamma-ray line pairs from a common element. Another makes a direct determination based on measurements of the line flux generated in the atmosphere, requires knowledge of the concentration of the component being used. The third, which makes use of a single line emitted from the surface where its flux can be established. The effects of stratigraphy on the differential attenuation method are studied, and calculations are reported which show that the measurement of atmospheric argon will be a sensitive indicator of the atmospheric fractionation accompanying CO2 precipitation in south polar regions.

  3. Elastic anisotropy of uniaxial mineralized collagen fibers measured using two-directional indentation. Effects of hydration state and indentation depth.

    PubMed

    Spiesz, Ewa M; Roschger, Paul; Zysset, Philippe K

    2012-08-01

    Mineralized turkey leg tendon (MTLT) is an attractive model of mineralized collagen fibers, which are also present in bone. Its longitudinal structure is advantageous for the relative simplicity in modeling, yet its anisotropic elastic properties remain unknown. The aim of this study was to quantify the extent of elastic anisotropy of mineralized collagen fibers by using nano- and microindentation to probe a number on MTLT samples in two orthogonal directions. The large dataset allowed the quantification of the extent of anisotropy, depending on the final indentation depth and on the hydration state of the sample. Anisotropy was observed to increase with the sample re-hydration process. Artifacts of indentation in a transverse direction to the main axis of the mineralized tendons in re-hydrated condition were observed. The indentation size effect, that is, the increase of the measured elastic properties with decreasing sampling volume, reported previously on variety of materials, was also observed in MTLT. Indentation work was quantified for both directions of indentation in dried and re-hydrated conditions. As hypothesized, MTLT showed a higher extent of anisotropy compared to cortical and trabecular bone, presumably due to the alignment of mineralized collagen fibers in this tissue. PMID:22664658

  4. Implications for Lithospheric and Asthenospheric Anisotropy from USArray-TA Splitting Intensity Measurements and 3-D Anisotropy Model of North America

    NASA Astrophysics Data System (ADS)

    Hongsresawat, S.; Panning, M. P.; Russo, R. M.; Foster, D. A.; Chevrot, S.; Monteiller, V.

    2013-12-01

    We present splitting intensity measurements of SKS waves observed at 1,436 USArray Transportable Array (USArray-TA) seismic stations which cover most of the contiguous U.S. for the first time. By fitting a sinusoidal to the backazimuthal dependence of splitting intensity, traditional splitting parameters, the polarization angle between the radial direction and the fast axis φ and the delay time between the fast and slow polarizations δt are obtained and used in comparison with absolute plate motion, geological basements, magnetic, gravity anomalies and lithospheric thickness to reveal the interactions between asthenospheric flow and lithospheric anisotropic structures of several geological regions of North America. Our preliminary results show that the Rocky Mountain front has a complicated flow due to transition in lithospheric thickness along absolute plate motion (APM) flow, the Gulf Coast has a strong APM asthenospheric signature in region of thin lithosphere, and the northern Central U.S. demonstrates evidence for interactions between asthenospheric and lithospheric signatures. We observe notable contrast between the Superior Province vs. the Tran-Hudson Orogeny where there is a clear relationship between the alignment of lithospheric texture, APM, and the strength of observed anisotropy. Aside from using these traditional splitting parameters φ and δt to reveal upper mantle structure beneath North America, we will further present a tomographic model based on finite-frequency effects in the splitting of SKS waves. Splitting intensity has a linear dependence of arbitrarily complex anisotropic structure, so instead of relying on a model of a single layer of anisotropy with a horizontal fast axis, we are capable of imaging three-dimensional anisotropic structure beneath North America. SKS--wave splitting measurements across the USArray--TA stations plotted on top of topography of North America. Black lines indicate the orientation of the fast polarization

  5. PWR and BWR spent fuel assembly gamma spectra measurements

    DOE PAGESBeta

    Vaccaro, S.; Tobin, Stephen J.; Favalli, Andrea; Grogan, Brandon R.; Jansson, Peter; Liljenfeldt, Henrik; Mozin, Vladimir; Hu, Jianwei; Schwalbach, P.; Sjoland, A.; et al

    2016-07-17

    A project to research the application of nondestructive assay (NDA) to spent fuel assemblies is underway. The research team comprises the European Atomic Energy Community (EURATOM), embodied by the European Commission, DG Energy, Directorate EURATOM Safeguards; the Swedish Nuclear Fuel and Waste Management Company (SKB); two universities; and several United States national laboratories. The Next Generation of Safeguards Initiative–Spent Fuel project team is working to achieve the following technical goals more easily and efficiently than in the past using nondestructive assay measurements of spent fuel assemblies: (1) verify the initial enrichment, burnup, and cooling time of facility declaration; (2) detectmore » the diversion or replacement of pins, (3) estimate the plutonium mass, (4) estimate the decay heat, and (5) determine the reactivity of spent fuel assemblies. This study focuses on spectrally resolved gamma-ray measurements performed on a diverse set of 50 assemblies [25 pressurized water reactor (PWR) assemblies and 25 boiling water reactor (BWR) assemblies]; these same 50 assemblies will be measured with neutron-based NDA instruments and a full-length calorimeter. Given that encapsulation/repository and dry storage safeguards are the primarily intended applications, the analysis focused on the dominant gamma-ray lines of 137Cs, 154Eu, and 134Cs because these isotopes will be the primary gamma-ray emitters during the time frames of interest to these applications. This study addresses the impact on the measured passive gamma-ray signals due to the following factors: burnup, initial enrichment, cooling time, assembly type (eight different PWR and six different BWR fuel designs), presence of gadolinium rods, and anomalies in operating history. As a result, to compare the measured results with theory, a limited number of ORIGEN-ARP simulations were performed.« less

  6. PRESAGE 3D dosimetry accurately measures Gamma Knife output factors

    NASA Astrophysics Data System (ADS)

    Klawikowski, Slade J.; Yang, James N.; Adamovics, John; Ibbott, Geoffrey S.

    2014-12-01

    Small-field output factor measurements are traditionally very difficult because of steep dose gradients, loss of lateral electronic equilibrium, and dose volume averaging in finitely sized detectors. Three-dimensional (3D) dosimetry is ideal for measuring small output factors and avoids many of these potential challenges of point and 2D detectors. PRESAGE 3D polymer dosimeters were used to measure the output factors for the 4 mm and 8 mm collimators of the Leksell Perfexion Gamma Knife radiosurgery treatment system. Discrepancies between the planned and measured distance between shot centers were also investigated. A Gamma Knife head frame was mounted onto an anthropomorphic head phantom. Special inserts were machined to hold 60 mm diameter, 70 mm tall cylindrical PRESAGE dosimeters. The phantom was irradiated with one 16 mm shot and either one 4 mm or one 8 mm shot, to a prescribed dose of either 3 Gy or 4 Gy to the 50% isodose line. The two shots were spaced between 30 mm and 60 mm apart and aligned along the central axis of the cylinder. The Presage dosimeters were measured using the DMOS-RPC optical CT scanning system. Five independent 4 mm output factor measurements fell within 2% of the manufacturer’s Monte Carlo simulation-derived nominal value, as did two independent 8 mm output factor measurements. The measured distances between shot centers varied by ±0.8 mm with respect to the planned shot displacements. On the basis of these results, we conclude that PRESAGE dosimetry is excellently suited to quantify the difficult-to-measure Gamma Knife output factors.

  7. An Alpha-Gamma Counter for Absolute Neutron Flux Measurement

    NASA Astrophysics Data System (ADS)

    Yue, A.; Greene, G.; Dewey, M.; Gilliam, D.; Nico, J.; Laptev, A.

    2012-03-01

    An alpha-gamma counter was used to measure the absolute neutron flux of a monochromatic cold neutron beam to sub-0.1,% precision. Simultaneously, the counter was used to calibrate a thin neutron flux monitor based on neutron absorption on ^6Li to the same precision. This monitor was used in the most precise beam-based measurement of the neutron lifetime, where the limiting systematic effect was the uncertainty in the neutron counting efficiency (0.3,%). The counter uses a thick target of ^10B-enriched boron carbide to completely absorb the beam. The rate of absorbed neutrons is determined by counting 478 keV gamma rays from neutron capture on ^10B with calibrated high-purity germanium detectors. The calibration results and the implications for the neutron lifetime will be discussed.

  8. Airborne gamma radiation soil moisture measurements over short flight lines

    NASA Technical Reports Server (NTRS)

    Peck, Eugene L.; Carrol, Thomas R.; Lipinski, Daniel M.

    1990-01-01

    Results are presented on airborne gamma radiation measurements of soil moisture condition, carried out along short flight lines as part of the First International Satellite Land Surface Climatology Project Field Experiment (FIFE). Data were collected over an area in Kansas during the summers of 1987 and 1989. The airborne surveys, together with ground measurements, provide the most comprehensive set of airborne and ground truth data available in the U.S. for calibrating and evaluating airborne gamma flight lines. Analysis showed that, using standard National Weather Service weights for the K, Tl, and Gc radiation windows, the airborne soil moisture estimates for the FIFE lines had a root mean square error of no greater than 3.0 percent soil moisture. The soil moisture estimates for sections having acquisition time of at least 15 sec were found to be reliable.

  9. Ultrashort Pulse Reflectometry (USPR) Density Profile Measurements on GAMMA-10

    NASA Astrophysics Data System (ADS)

    Domier, C. W.; Roh Luhmann, Y., Jr.; Mase, A.; Kubota, S.

    1999-11-01

    Ultrashort pulse reflectometry (USPR) involves time-of-flight measurements of extremely broadband, high speed chirped signals ( ns sweep times). A multichannel USPR system has been installed on the central cell of the GAMMA-10 mirror machine located at the University of Tsukuba, Japan. Here, the output from a 65 ps FWHM impulse generator is stretched and amplified to form a 10 ns duration, 11-18 GHz chirp signal. A five channel X-mode USPR receiver, with frequency channels at 12, 13, 15, 16 and 17 GHz, measures the double-pass time delay of each reflected subpacket simultaneously with 25 ps time resolution. Density profile and fluctuation data collected on GAMMA-10 will be presented.

  10. Implications of final L3 measurement of {sigma}{sub tot}({gamma}{gamma}{yields}bb)

    SciTech Connect

    Chyla, Jiri

    2006-02-01

    The excess of data on the total cross section of bb production in {gamma}{gamma} collisions over QCD predictions, observed by L3, OPAL and DELPHI Collaborations at LEP2, has so far defied explanation. The recent final analysis of L3 data has brought important new information concerning the dependence of the observed excess on the {gamma}{gamma} collisions energy W{sub {gamma}}{sub {gamma}}. The implications of this dependence are discussed.

  11. Airborne Spectral Measurements of Surface-Atmosphere Anisotropy for Skukuza and Mongu Sites

    NASA Technical Reports Server (NTRS)

    Gatebe, C. K.; King, Michael D.; Arnold, G. T.; Li, J. Y.

    2001-01-01

    The Cloud Absorption Radiometer (CAR) was flown aboard the University of Washington Convair CV-580 research aircraft and took measurements on 23 flights between August 15 and September 16. On 12 of those flights, BRF (bidirectional reflection function) measurements were obtained over different natural surfaces and ecosystems in southern Africa. The BRF measurements were done to characterize surface anisotropy in support of SAFARI 2000 science objectives principally to validate products from NASA's EOS (Earth Observing System) satellites, and to parameterize and validate BRF models. In this paper we present results of BRFs taken over two EOS validation sites: Skukuza tower, South Africa (25.0 S, 31.5 E) and Mongu tower, Zambia (15.4 S, 23.3 E). The CAR is capable of measuring scattered light in fourteen spectral bands. The scan mirror, rotating at 100 rpm, directs the light into a Dall-Kirkham telescope where the beam is split into nine paths. Eight light beams pass through beam splitters, dichroics, and lenses to individual detectors (0.34-1.27 microns), and finally are registered by eight data channels. They are sampled simultaneously and continuously. The ninth beam passes through a spinning filter wheel to an InSb detector cooled by a Stirling cycle cooler. Signals registered by the ninth data channel are selected from among six spectral channels (1.55-2.30 microns). The filter wheel can either cycle through all six spectral bands at a prescribed interval (usually changing filter every fifth scan line), or lock onto any one of the six spectral bands and sample it continuously. To measure the BRF of the surface-atmosphere system, the University of Washington CV-580 had to bank at a comfortable roll angle of approximately 20 degrees and fly in a circle about 3 km in diameter above the surface for roughly two minutes. Replicated observations (multiple circular orbits) were acquired over selected surfaces so that average BRF smooth out small-scale surface and

  12. Airborne spectral Measurements of Surface-Atmosphere Anisotropy for Several Surfaces and Ecosystem over Southern Africa

    NASA Technical Reports Server (NTRS)

    Gatebe, Charles K.; King, M. D.; Arnold, G. T.; Li, J. Y.; Lau, William K. M. (Technical Monitor)

    2001-01-01

    The Cloud Absorption Radiometer (CAR) was flown aboard the University of Washington Convair CV-580 research aircraft and took measurements on 23 flights between August 15 and September 16. On 12 of those flights, BRF measurements were obtained over different natural surfaces and ecosystem in southern Africa. The BRF measurements were done to characterize surface anisotropy in support of SAFARI 2000 science objectives principally to validate products from NASA's EOS satellites, and to parameterize and validate BRF models. In this paper we present results of BRFs taken over two EOS validation sites: Skukuza tower, South Africa (25.0 deg S, 31.5 deg E) and Mongu tower, Zambia (15.4 deg S, 23.3 deg E). Additional sites are also considered and include, Maun tower, Botswana (20.0 deg S, 23.5 deg E), Sowa Pan, Botswana (20.6 deg S, 26.2 deg E) and Etosha Pan, Namibia (19.0 deg S, 16.0 deg E). The CAR is capable of measuring scattered light in fourteen spectral bands. The scan mirror, rotating at 100 rpm, directs the light into a Dall-Kirkham telescope where the beam is split into nine paths. Eight light beams pass through beam splitters, dichroics, and lenses to individual detectors (0.34-1.27 micrometers), and finally are registered by eight data channels. They are sampled simultaneously and continuously. The ninth beam passes through a spinning filter wheel to an InSb detector cooled by a Stirling cycle cooler. Signals registered by the ninth data channel are selected from among six spectral channels (1.55-2.30 micrometers). The filter wheel can either cycle through all six spectral bands at a prescribed interval (usually changing filter every fifth scan line), or lock onto any one of the six spectral bands and sample it continuously. To measure the BRF of the surface-atmosphere system, the University of Washington CV-580 had to bank at a comfortable roll angle of approximately 20 degrees and fly in a circle about 3 km in diameter above the surface for roughly two

  13. Neutron and Gamma Ray Scattering Measurements for Subsurface Geochemistry

    NASA Astrophysics Data System (ADS)

    Ellis, Darwin V.

    1990-10-01

    Developed for the oil industry, well logging instrumentation based on electrical, acoustic, and nuclear measurements has been providing information about the localization and evaluation of hydrocarbon-bearing strata for petroleum geologists and engineers since 1927. This method of exploring properties of the earth's crust without taking physical samples is attracting a growing audience of geologists and geophysicists because of recent developments that permit nondestructive measurements of subsurface geochemistry. A combination of nuclear measurement techniques, which use gamma ray and neutron sources, can provide detailed information on rock composition of interest to both industry and academia.

  14. Measuring the Alfvénic nature of the interstellar medium: Velocity anisotropy revisited

    SciTech Connect

    Burkhart, Blakesley; Lazarian, A.; Leão, I. C.; De Medeiros, J. R.; Esquivel, A.

    2014-08-01

    The dynamics of the interstellar medium (ISM) are strongly affected by turbulence, which shows increased anisotropy in the presence of a magnetic field. We expand upon the Esquivel and Lazarian method to estimate the Alfvén Mach number using the structure function anisotropy in velocity centroid data from Position-Position-Velocity maps. We utilize three-dimensional magnetohydrodynamic simulations of fully developed turbulence, with a large range of sonic and Alfvénic Mach numbers, to produce synthetic observations of velocity centroids with observational characteristics such as thermal broadening, cloud boundaries, noise, and radiative transfer effects of carbon monoxide. In addition, we investigate how the resulting anisotropy-Alfvén Mach number dependency found in Esquivel and Lazarian might change when taking the second moment of the Position-Position-Velocity cube or when using different expressions to calculate the velocity centroids. We find that the degree of anisotropy is related primarily to the magnetic field strength (i.e., Alfvén Mach number) and the line-of-sight orientation, with a secondary effect on sonic Mach number. If the line of sight is parallel to up to ≈45 deg off of the mean field direction, the velocity centroid anisotropy is not prominent enough to distinguish different Alfvénic regimes. The observed anisotropy is not strongly affected by including radiative transfer, although future studies should include additional tests for opacity effects. These results open up the possibility of studying the magnetic nature of the ISM using statistical methods in addition to existing observational techniques.

  15. A Degree-Scale Measurement of the Anisotropy in the Cosmic Microwave Background

    NASA Technical Reports Server (NTRS)

    Wollack, Ed; Jarosik, Norm; Netterfield, Barth; Page, Lyman; Wilkinson, David

    1995-01-01

    We report the detection of anisotropy in the microwave sky at 3O GHz and at l deg angular scales. The most economical interpretation of the data is that the fluctuations are intrinsic to the cosmic microwave background. However, galactic free-free emission is ruled out with only 90% confidence. The most likely root-mean-squared amplitude of the fluctuations, assuming they are described by a Gaussian auto-correlation function with a coherence angle of 1.2 deg, is 41(+16/-13) (mu)K. We also present limits on the anisotropy of the polarization of the cosmic microwave background.

  16. Measurements of Secondary Cosmic Microwave Background Anisotropies with the South Pole Telescope

    NASA Astrophysics Data System (ADS)

    Lueker, Martin

    The South Pole Telescope is a 10m millimeter-wavelength telescope for finding galaxy clusters via the thermal Sunyaev-Zel'dovich (tSZ) effect. This thesis is divided into two parts. The first part describes the development of the kilopixel SPT-SZ receiver and the frequency-domain multiplexor (fMUX). The second part describes the first SPT power spectrum measurement and the first detection of the tSZ power spectrum. The SPT-SZ focal plane consists of 960 spiderweb coupled transition-edge sensors. Due to strong electro-thermal feedback, these devices have good sensitivity and linearity, though risk spontaneous oscillations. Adding heat capacity to these devices can ensure stability, so long as the loopgain, L , is less than Gint/G 0, the ratio between the thermal conductances linking the TES to the heat capacity and linking the heat capacity to the bath. I describe as experimental technique for measuring the internal thermal structure of these devices, allowing for rapid sensor evaluation. The fMUX readout system reduces wiring complexity in this receiver by AC-biasing each sensor at a unique frequency and sending signals from multiple bolometers along one pair of wires. The Series SQUID Arrays (SSAs) used to read changes in bolometer current are notably non-linear and extremely sensitive to ambient magnetic fields. The SSAs are housed in compact magnetic shielding modules which reduces their effective area to 80 mphi0/gauss. The SSA are fedback with a flux-locked loop to improve their linearity and dynamic range, and decrease their input reactance. The FLL is bandwidth of 1 MHz with a measured loopgain of 10. In the current implementation, this bandwidth is limited between the SQUID input coil and other reactances, which I study in Chapter 4. In the second part of the thesis I present power spectrum measurements for the first 100 deg2 field observed by the SPT. On angular scales where the primary CMB anisotropy is dominant, ℓ ≲ 3000, the SPT power spectrum is

  17. Gamma-ray backscatter for body composition measurement.

    PubMed

    Morgan, H M; Shakeshaft, J T; Lillicrap, S C

    1998-01-01

    The purpose of this study was to examine the potential of using backscatter information to assess regional body composition at selected sites. Two measurement techniques are examined: the measurement of the ratio of coherent to Compton scatter, and the measurement of the Compton scatter profile. Two possible applications are considered: the measurement of trabecular bone mineral density, and the measurement of the average fat/muscle ratio in a tissue volume. The results presented indicate that the analysis of coherent and Compton backscattered gamma-ray spectra from an 241Am source has the potential for measuring both trabecular bone mineral density and average fat/muscle ratio in a tissue volume, with a low absorbed dose to the subject. PMID:9569541

  18. Gamma Ray Burst 150518a measured at different wavelengths

    NASA Astrophysics Data System (ADS)

    Apala, Ellizabeth Ann; Soderberg, Alicia Margarita; West, Michael

    2016-01-01

    Gamma Ray Burst (GRB's), extremely energetic flashes of Gamma Rays, are caused by either deaths of massive unstable stars or colliding binary neutron stars. A unique burst, GRB 150518a, had two recorded bursts fifteen minutes apart which is very rare and is considered to be ultra-long, lasting around thirty minutes total and is associated with a Supernova explosion. GBR 150518a is also extremely close compared to the average burst being measured to have a redshift of .2, this is important to note because GRB's measuring less than a redshift of .3 only are seen every ten years. Gamma rays are emitted by supernovae, neutron stars, black holes, and quasars and by studying GRB's it allows us to see more deeply into how these objects function. The first few days of GRB 150518as' detected afterglow was plotted in different wavelengths, including optical, x-ray, radio, and infrared, in flux verses time. Data is continuously being added as time goes on. This research is funded by the NSF, grant number 1358990.

  19. Gamma-ray measurements of a 6-kilogram neptunium sphere

    SciTech Connect

    Moss, C. E.; Frankle, C. M.

    2002-01-01

    In order to better determine the properties of {sup 237}Np for criticality safety and nuclear nonproliferation, especially its critical mass, 6070-gram solid sphere was cast on 15 May 2001 in a hot cell. The casting sprue was cut off on a lathe and the casting ground to a final diameter of 8.29 cm. The sphere was enclosed in a spherical tungsten shell 0.523-cm thick to reduce the gamma-ray dose. The neptunium and the tungsten were doubly encapsulated in welded, spherical nickel shells, each 0.381-cm thick. The sprue material was analyzed by mass spectrometry. Here we report the results of the first gamma-ray measurements of this unique item.

  20. In-Plane Electronic Anisotropy of Underdoped ___122___ Fe-Arsenide Superconductors Revealed by Measurements of Detwinned Single Crystals

    SciTech Connect

    Fisher, Ian Randal

    2012-05-08

    The parent phases of the Fe-arsenide superconductors harbor an antiferromagnetic ground state. Significantly, the Neel transition is either preceded or accompanied by a structural transition that breaks the four fold symmetry of the high-temperature lattice. Borrowing language from the field of soft condensed matter physics, this broken discrete rotational symmetry is widely referred to as an Ising nematic phase transition. Understanding the origin of this effect is a key component of a complete theoretical description of the occurrence of superconductivity in this family of compounds, motivating both theoretical and experimental investigation of the nematic transition and the associated in-plane anisotropy. Here we review recent experimental progress in determining the intrinsic in-plane electronic anisotropy as revealed by resistivity, reflectivity and ARPES measurements of detwinned single crystals of underdoped Fe arsenide superconductors in the '122' family of compounds.

  1. DIRECT MEASUREMENT OF THE ANGULAR POWER SPECTRUM OF COSMIC MICROWAVE BACKGROUND TEMPERATURE ANISOTROPIES IN THE WMAP DATA

    SciTech Connect

    Chiang, Lung-Yih; Chen, Fei-Fan

    2012-05-20

    The angular power spectrum of the cosmic microwave background temperature anisotropies is one of the most important characteristics in cosmology that can shed light on the properties of the universe such as its geometry and total density. Using flat sky approximation and Fourier analysis, we estimate the angular power spectrum from an ensemble of the least foreground-contaminated square patches from the Wilkinson Microwave Anisotropy Probe W and V frequency band map. This method circumvents the issue of foreground cleaning and that of breaking orthogonality in spherical harmonic analysis because we are able to mask out the bright Galactic plane region, thereby rendering a direct measurement of the angular power spectrum. We test and confirm the Gaussian statistical characteristic of the selected patches, from which the first and second acoustic peaks of the power spectrum are reproduced, and the third peak is clearly visible, albeit with some noise residual at the tail.

  2. Anisotropy measurements of intrinsic fluorescence of prenyllipids reveal much higher mobility of plastoquinol than alpha-tocopherol in model membranes.

    PubMed

    Jemioła-Rzemińska, Małgorzata; Kruk, Jerzy; Strzałka, Kazimierz

    2003-04-01

    As an alternative to a fluorescent probe approach, the intrinsic fluorescence of reduced forms of prenylquinones has been exploited, which offers a convenient means of determining directly motional properties of these molecules. The steady-state fluorescence anisotropy measurements of plastoquinols (PQH(2)) and alpha-tocopherol (alpha-Toc) incorporated into phospholipid liposomes have been performed. The effect of prenyllipid concentration, PQH(2) side chain length and the composition of the membranes has been studied. For the data interpretation, the fundamental anisotropy of alpha-Toc, PQH(2), ubiquinol-10 and alpha-tocopherolquinol, as well as the angles between the absorption and emission transition moments have been also determined. It was concluded that alpha-Toc shows very low mobility in the lipid bilayer, whereas PQH(2)-9 displays significant motional freedom in dipalmitoylphosphatidylcholine vesicles and even higher in egg yolk lecithin membranes. PMID:12691855

  3. Gamma-ray scattering for fat fraction measurement.

    PubMed

    Shakeshaft, J; Morgan, H M; Lillicrap, S C

    1997-07-01

    The work reported examines the potential of using gamma-ray photon backscatter information to measure in vivo the percentage of fat in specific tissue volumes. 241Am gamma rays are used as the source and the backscatter detected with a hyperpure germanium detector, with ethanol (approximately 80% fat, 20% muscle) and water (muscle) being used as tissue substitutes. Two measurement techniques are examined; the measurement of the ratio of coherent scatter to Compton scatter and the measurement of the Compton scatter profile. Both are shown to be sensitive to the composition difference between ethanol and water. For the coherent-Compton scatter ratio, the measured difference between water and ethanol is 1.85:1, close to the value calculated (about 2:1). A similar difference in the coherent-Compton ratios between muscle and fat is calculated (2.2:1). The FWHM of the Compton profile has also been shown to vary with tissue composition with a difference of 0.10 keV (5%) between the ethanol and water profile widths. PMID:9253048

  4. Gamma-ray scattering for fat fraction measurement

    NASA Astrophysics Data System (ADS)

    Shakeshaft, J.; Morgan, H. M.; Lillicrap, S. C.

    1997-07-01

    The work reported examines the potential of using gamma-ray photon backscatter information to measure in vivo the percentage of fat in specific tissue volumes. gamma rays are used as the source and the backscatter detected with a hyperpure germanium detector, with ethanol (approximately 80% fat, 20% muscle) and water (muscle) being used as tissue substitutes. Two measurement techniques are examined; the measurement of the ratio of coherent scatter to Compton scatter and the measurement of the Compton scatter profile. Both are shown to be sensitive to the composition difference between ethanol and water. For the coherent - Compton scatter ratio, the measured difference between water and ethanol is 1.85:1, close to the value calculated (about 2:1). A similar difference in the coherent - Compton ratios between muscle and fat is calculated (2.2:1). The FWHM of the Compton profile has also been shown to vary with tissue composition with a difference of 0.10 keV (5%) between the ethanol and water profile widths.

  5. RADSAT Benchmarks for Prompt Gamma Neutron Activation Analysis Measurements

    SciTech Connect

    Burns, Kimberly A.; Gesh, Christopher J.

    2011-07-01

    The accurate and efficient simulation of coupled neutron-photon problems is necessary for several important radiation detection applications. Examples include the detection of nuclear threats concealed in cargo containers and prompt gamma neutron activation analysis for nondestructive determination of elemental composition of unknown samples. High-resolution gamma-ray spectrometers are used in these applications to measure the spectrum of the emitted photon flux, which consists of both continuum and characteristic gamma rays with discrete energies. Monte Carlo transport is the most commonly used simulation tool for this type of problem, but computational times can be prohibitively long. This work explores the use of multi-group deterministic methods for the simulation of coupled neutron-photon problems. The main purpose of this work is to benchmark several problems modeled with RADSAT and MCNP to experimental data. Additionally, the cross section libraries for RADSAT are updated to include ENDF/B-VII cross sections. Preliminary findings show promising results when compared to MCNP and experimental data, but also areas where additional inquiry and testing are needed. The potential benefits and shortcomings of the multi-group-based approach are discussed in terms of accuracy and computational efficiency.

  6. Consistent Small-Sample Variances for Six Gamma-Family Measures of Ordinal Association

    ERIC Educational Resources Information Center

    Woods, Carol M.

    2009-01-01

    Gamma-family measures are bivariate ordinal correlation measures that form a family because they all reduce to Goodman and Kruskal's gamma in the absence of ties (1954). For several gamma-family indices, more than one variance estimator has been introduced. In previous research, the "consistent" variance estimator described by Cliff and colleagues…

  7. Direct measurement of anisotropy of interfacial free energy from grain boundary groove morphology in transparent organic metal analong systems

    SciTech Connect

    Rustwick, Bryce A.

    2005-08-01

    Both academia and industry alike have paid close attention to the mechanisms of microstructural selection during the solidification process. The forces that give rise to and the principles which rule the natural selection of particular morphologies are important to understanding and controlling new microstructures. Interfacial properties play a very crucial role to the selection of such microstructure formation. In the solidification of a metallic alloy, the solid-liquid interface is highly mobile and responds to very minute changes in the local conditions. At this interface, the driving force must be large enough to drive solute diffusion, maintain local curvature, and overcome the kinetic barrier to move the interface. Therefore, the anisotropy of interfacial free energy with respect to crystallographic orientation is has a significant influence on the solidification of metallic systems. Although it is generally accepted that the solid-liquid interfacial free energy and its associated anisotropy are highly important to the overall selection of morphology, the confident measurement of these particular quantities remains a challenge, and reported values are scarce. Methods for measurement of the interfacial free energy include nucleation experiments and grain boundary groove experiments. The predominant method used to determine anisotropy of interfacial energy has been equilibrium shape measurement. There have been numerous investigations involving grain boundaries at a solid-liquid interface. These studies indicated the GBG could be used to describe various interfacial energy values, which affect solidification. Early studies allowed for an estimate of interfacial energy with respect to the GBG energy, and finally absolute interfacial energy in a constant thermal gradient. These studies however, did not account for the anisotropic nature of the material at the GBG. Since interfacial energy is normally dependent on orientation of the crystallographic plane of the

  8. Guide to plutonium isotopic measurements using gamma-ray spectrometry

    SciTech Connect

    Lemming, J.F.; Rakel, D.A.

    1982-08-26

    Purpose of this guide is to assist those responsible for plutonium isotopic measurements in the application of gamma-ray spectrometry. Objectives are to promote an understanding of the measurement process, including its limitations and applicability, by reviewing the general features of a plutonium spectrum and identifying the quantities which must be extracted from the data; to introduce state-of-the-art analysis techniques by reviewing four isotopic analysis packages and identifying their differences; to establish the basis for measurement control and assurance by discussing means of authenticating the performance of a measurement system; and to prepare for some specific problems encountered in plutonium isotopic analyses by providing solutions from the practical experiences of several laboratories. 29 references, 12 figures, 17 tables.

  9. Magnetic susceptibility anisotropy: cylindrical symmetry from macroscopically ordered anisotropic molecules and accuracy of MRI measurements using few orientations.

    PubMed

    Wisnieff, Cynthia; Liu, Tian; Spincemaille, Pascal; Wang, Shuai; Zhou, Dong; Wang, Yi

    2013-04-15

    White matter is an essential component of the central nervous system and is of major concern in neurodegenerative diseases such as multiple sclerosis (MS). Recent MRI studies have explored the unique anisotropic magnetic properties of white matter using susceptibility tensor imaging. However, these measurements are inhibited in practice by the large number of different head orientations needed to accurately reconstruct the susceptibility tensor. Adding reasonable constraints reduces the number of model parameters and can help condition the tensor reconstruction from a small number of orientations. The macroscopic magnetic susceptibility is decomposed as a sum of molecular magnetic polarizabilities, demonstrating that macroscopic order in molecular arrangement is essential to the existence of and symmetry in susceptibility anisotropy and cylindrical symmetry is a natural outcome of an ordered molecular arrangement. Noise propagation in the susceptibility tensor reconstruction is analyzed through its condition number, showing that the tensor reconstruction is highly susceptible to the distribution of acquired subject orientations and to the tensor symmetry properties, with a substantial over- or under-estimation of susceptibility anisotropy in fiber directions not favorably oriented with respect to the acquired orientations. It was found that a careful acquisition of three non-coplanar orientations and the use of cylindrical symmetry guided by diffusion tensor imaging allowed reasonable estimation of magnetic susceptibility anisotropy in certain major white matter tracts in the human brain. PMID:23296181

  10. Partial Anhysteretic Anisotropy Measured in the Greys Landing Ignimbrite of the Central Snake River Plain

    NASA Astrophysics Data System (ADS)

    Rea-Downing, G. H.; Finn, D. R.; Coe, R. S.; Brown, E. D.; Reichow, M. K.; Knott, T.; Branney, M. J.

    2014-12-01

    Magnetic remanence directions recorded in the glassy sub-lithologies of mid-Miocene rheomorphic Snake River Plain ignimbrites are often discrepant compared to the more reliable directions in crystalline centers and underlying baked paleosols. The rocks have undergone no tectonic strain, and the rheomorphic deformation preserved in the rock occurs at ˜800°C, above magnetic blocking temperatures. Accounting for the discrepantly shallow directions is critical for the use of magnetic remanence for stratigraphic correlation and structural/tectonic reconstructions. Here we present paleomagnetic and rock magnetic data from the Grey's Landing Ignimbrite that demonstrate a strong magnetic anisotropy carried by pseudo-single to single domain magnetite grains which deflect the remanence direction by up to 40°. Strongly lineated anisotropic samples collected at distant sections ( ˜20 km separation) have their remanence deflected toward the respective flow directions inferred from their directions of maximum magnetic susceptibility (K1). Shallow K1 directions in the basal vitrophyre cause a shallowing of magnetic remanence, while a range of steep to shallow K1 directions in the folded upper vitrophyre cause both a steepening and shallowing of the remanence, respectively. There is a strong relationship between the magnitudes of remanence deflection, anisotropy of thermal remanence, coercivity, and strength of natural remanent magnetization between individual samples. There is also a strong relationship between the magnitudes of partial anisotropy of anhysteretic remanent magnetization (pAARM) and the deflection of the remanence vector difference directions, which both increase significantly with higher alternating magnetic fields. Correction of the vector difference direction using the inverse of the pAARM tensor for the same AF range is moderately successful. Previous work suggests that curvilinear demagnetization trends in the basal vitrophyre of an ignimbrite were

  11. 3D parameter to quantify the anisotropy measurement of periodic structures on rough surfaces.

    PubMed

    Guillemot, G; Bigerelle, M; Khawaja, Z

    2014-01-01

    In this paper, a new 3D roughness parameter, Sreg, is proposed to quantify the regularity of a surface, independent of the amplitude and the scanning length units of the surface. The efficiency of this parameter is tested on noisy periodical surfaces with degrees of anisotropy. This parameter lies between zero (perfect noise) and 100% (a perfect periodic surface). This parameter enables the identification of the anisotropy directions of regularity for a given surface. For a periodical surface, the greater the noise, the lower the anisotropy. A direction function is proposed to analyse the direction of regularity of a rough surface, which then permits characterization of the directional regularity of the topography. The regularity parameter can be used for several purposes: to identify the direction of periodical structures formed by laser-pulsed radiations on the surface of solid workpieces; to examine the reproducibility of surface machining methods such as finishing process; and to identify the surface regularity produced by abrasive machining, such as precision surface grain, abrasive slotting, and lapping. PMID:23824916

  12. Filter clogging by the extracted gamma prime and its measurement

    NASA Technical Reports Server (NTRS)

    Harf, F. H.

    1990-01-01

    The extraction of gamma-prime sample residues from Ni-based superalloys varies greatly in efficiency with the type of heat-treatment that had previously been applied to the alloy; this effect has prompted the present formulation of a standardized procedure for measuring the residues' filter-clogging factor (FCF). The FCF differences between heat treatments can be correlated with the quantity and size distribution of extracted particles; this procedure could accordingly furnish a means of checking the accuracy of heat treaments.

  13. Measurement of Branching Fractions in Radiative BDecays to eta K gamma and Search for B Decays to eta' K gamma

    SciTech Connect

    Aubert, B.

    2006-03-31

    The authors present measurements of the B {yields} {eta}K{gamma} branching fractions and upper limits for the B {yields} {eta}'K{gamma} branching fractions. For B{sup +} {yields} {eta}K{sup +}{gamma} they also measure the time-integrated charge asymmetry. The data sample, collected with the BABAR detector at the Stanford Linear Accelerator Center, represents 232 x 10{sup 6} produced B{bar B} pairs. The results for branching fractions and upper limits at 90% C.L. in units of 10{sup -6} are: {Beta}(B{sup 0} {yields} {eta}K{sup 0}{gamma}) = 11.3{sub -2.6}{sup +2.8} {+-} 0.6, {Beta}(B{sup +} {yields} {eta}K{sup +}{gamma}) = 10.0 {+-} 1.3 {+-} 0.5, {Beta}(B{sup 0} {yields} {eta}'K{sup 0}{gamma}) < 6.6, {Beta}(B{sup +} {yields} {eta}'K{sup +}{gamma}) < 4.2. The charge asymmetry in the decay B{sup +} {yields} {eta}K{sup +}{gamma} is {Alpha}{sub ch} = -0.09 {+-} 0.12 {+-} 0.01. The first errors are statistical and the second systematic.

  14. Direct gamma and gamma-jet measurement capability of ATLAS for Pb+Pb collisions

    SciTech Connect

    Baker, M.

    2009-12-01

    The ATLAS detector at the LHC is capable of efficiently separating photons and neutral hadrons based on their shower shapes over a wide range in {eta}, {phi}, and E{sub T}, either in addition to or instead of isolation cuts. This provides ATLAS with a unique strength for direct photon and {gamma}-jet physics as well as access to the unique capability to measure non-isolated photons from fragmentation or from the medium. We present a first look at the ATLAS direct photon measurement capabilities in Pb+Pb and, for reference, p+p collisions at {radical}s{sub NN} = 5.5 TeV over the region |{eta}| < 2.4.

  15. The direct measurement of dose enhancement in gamma test facilities

    SciTech Connect

    Burke, E.A.; Snowden, D.P. ); Cappelli, J.R.; Mittleman, S. ); Lowe, L.F.

    1989-12-01

    The design and use of a dual cavity ionization chamber for routine measurement of dose enhancement factors in Co-60 gamma test facilities is described. The enhancement factors can be derived directly from the chamber measurements without recourse to reference data that may be difficult to obtain. It is shown, in agreement with earlier work, that the maximum dose enhancement factors can be altered by a factor two as a result of Compton scatter from relatively small amounts of low or high atomic number materials next to the target. The dual chamber permits the ready detection of such effects. This relatively simple device reliably reproduced earlier results obtained by more involved equipment and procedures. Measured enhancement factors are reported for new material combinations not previously examined and compared with recent calculations.

  16. On the anisotropy of perceived ground extents and the interpretation of walked distance as a measure of perception.

    PubMed

    Li, Zhi; Sun, Emily; Strawser, Cassandra J; Spiegel, Ariana; Klein, Brennan; Durgin, Frank H

    2013-04-01

    Two experiments are reported concerning the perception of ground extent to discover whether prior reports of anisotropy between frontal extents and extents in depth were consistent across different measures (visual matching and pantomime walking) and test environments (outdoor environments and virtual environments). In Experiment 1 it was found that depth extents of up to 7 m are indeed perceptually compressed relative to frontal extents in an outdoor environment, and that perceptual matching provided more precise estimates than did pantomime walking. In Experiment 2, similar anisotropies were found using similar tasks in a similar (but virtual) environment. In both experiments pantomime walking measures seemed to additionally compress the range of responses. Experiment 3 supported the hypothesis that range compression in walking measures of perceived distance might be due to proactive interference (memory contamination). It is concluded that walking measures are calibrated for perceived egocentric distance, but that pantomime walking measures may suffer range compression. Depth extents along the ground are perceptually compressed relative to frontal ground extents in a manner consistent with the angular scale expansion hypothesis. PMID:22889186

  17. The Locations of Gamma-Ray Bursts Measured by Comptel

    NASA Technical Reports Server (NTRS)

    Kippen, R. Marc; Ryan, James M.; Connors, Alanna; Hartmann, Dieter H.; Winkler, Christoph; Kuiper, Lucien; Varendorff, Martin; McConnell, Mark L.; Hurley, Kevin; Hermsen, Wim; Schoenfelder, Volker

    1998-01-01

    The COMPTEL instrument on the Compton Gamma Ray Observatory is used to measure the locations of gamma-ray bursts through direct imaging of MeV photons. In a comprehensive search, we have detected and localized 29 bursts observed between 1991 April 19 and 1995 May 31. The average location accuracy of these events is 1.25 deg (1 sigma), including a systematic error of approx. 0.5 deg, which is verified through comparison with Interplanetary Network (IPN) timing annuli. The combination of COMPTEL and IPN measurements results in locations for 26 of the bursts with an average "error box" area of only approx. 0.3 deg (1 sigma). We find that the angular distribution of COMPTEL burst locations is consistent with large-scale isotropy and that there is no statistically significant evidence of small-angle autocorrelations. We conclude that there is no compelling evidence for burst repetition since no more than two of the events (or approx. 7% of the 29 bursts) could possibly have come from the same source. We also find that there is no significant correlation between the burst locations and either Abell clusters of galaxies or radio-quiet quasars. Agreement between individual COMPTEL locations and IPN annuli places a lower limit of approx. 100 AU (95% confidence) on the distance to the stronger bursts.

  18. Electric Field Change Measurements of a Terrestrial Gamma Ray Flash

    NASA Astrophysics Data System (ADS)

    Marshall, Thomas; Karunarathne, Sumedhe; Stolzenburg, Maribeth

    2016-04-01

    Cummer et al. [GRL, 2014] reported on two terrestrial gamma ray flashes (TGFs) detected by the Gamma ray Burst Monitor (GBM) on the Fermi satellite. At a range of 632 km we detected an electric field change pulse associated with the first of these TGFs. The sensor bandwidth was 0.16 Hz - 2.6 MHz and was sampled at 5 MS/s. The measured zero-to-peak amplitude was 3.1 V/m. Assuming a 1/R range dependence, the amplitude range normalized to 100 km would be about 20 V/m. However, a little more than half of the path from the TGF to the sensor was over land rather than ocean, which should cause the attenuation to be greater than 1/R. Based on recent measurements of Kolmasova et al. (2015 AGU Fall Meeting), we estimate that the real peak amplitude was 40 - 50 V/m. The detected pulse was bipolar with a leading positive peak and had an overall duration of about 50 μs; these characteristics are typical of initial breakdown pulses (IBPs) that occur at the beginning of intracloud (IC) flashes. However, the pulse amplitude is an order of magnitude larger than typical IBPs. These data support the notion that IBPs of IC flashes cause TGFs [e.g., Shao et al., JGR 2010; Lu et al., GRL 2010; Cummer et al., GRL 2014].

  19. Measurement of magnetostriction and induced magnetic anisotropy by SAMR method in Co-rich stress + field annealed amorphous ribbons

    NASA Astrophysics Data System (ADS)

    Blanco, J. M.; González, J.; Vázquez, M.; Barandiarán, J. M.; Hernando, A.

    1991-10-01

    The saturation magnetostriction (λ s) and induced magnetic anisotropy ( Kind) in (Co 0.95Fe 0.05) 80Si 10B 10 annealed amorphous alloy ribbons have been measured at room temperature with the SAMR (small-angle magnetization rotation) method. The ribbons were annealed under simulataneous action of a stress and/or magnetic field. The variations of λ s and Kind show parallel trends in the cases of stress and stress+field annealings but not for single field annealing. These variations are connected with microstructural changes originated during the treatments.

  20. Magneto-optical measurement of anisotropy energy constant(s) for amorphous rare earth, transition metal alloys

    SciTech Connect

    Uber, R.E.; Mansuripur, M.

    1988-11-01

    Optical investigation of magneto-optical films is complementary to conventional torque and VSM magnetometry. In the authors' laboratory, they are now measuring anisotropy energy constants of RE-TM thin films at temperatures from ambient to 150/sup 0/C. An in-plane magnetic field (up to 16.5 KOe) is applied to a saturated sample with perpendicular magnetization. The movement away from the perpendicular direction is monitored using the polar Kerr effect. At the HeNe wavelength, the Kerr effect is principally due to the top 500 angstroms of the transition metal subnetwork in the films.

  1. Measurement of Gamma Knife registered helmet factors using MOSFETs

    SciTech Connect

    Kurjewicz, Laryssa; Berndt, Anita

    2007-03-15

    The relative dose rate for the different Gamma Knife registered helmets (4, 8, 14, and 18 mm) is characterized by their respective helmet factors. Since the plateau of the dose profile for the 4 mm helmet is at most 1 mm wide, detector choices are limited. Traditionally helmet factors have been measured using 1x1x1 mm{sup 3} thermoluminescent dosimeters (TLDs). However, these are time-consuming, cumbersome measurements. This article investigates the use of metal-oxide-semiconductor field effect transistors (MOSFETs) (active area of 0.2x0.2 mm{sup 2}) as a more accurate and convenient dosimeter. Their suitability for these measurements was confirmed by basic characterization measurements. Helmet factors were measured using both MOSFETs and the established TLD approach. A custom MOSFET cassette was designed in analogy to the Elekta TLD cassette (Elekta Instruments AB) for use with the Elekta dosimetry sphere. Although both dosimeters provided values within 3% of the manufacturer's suggestion, MOSFETs provided superior accuracy and precision, in a fraction of the time required for the TLD measurements. Thus, MOSFETs proved to be a reasonable alternative to TLDs for performing helmet factor measurements.

  2. Single orthogonal sinusoidal grating for gamma correction in digital projection phase measuring profilometry

    NASA Astrophysics Data System (ADS)

    Xiao, Yanshan; Cao, Yiping; Wu, Yingchun; Shi, Shunping

    2013-05-01

    The gamma nonlinearity of the digital projector leads to obvious phase errors in the phase measuring profilometry. Based on the Fourier spectrum analysis of the captured pattern, a robust gamma correction method is proposed in this paper. An orthogonal sinusoidal grating precoded with two different known gamma values is used to evaluate the gamma value of the pattern. The evaluated gamma value is then encoded into the computer-generated phase-shifting fringe patterns before the fringe patterns are sent to the digital projector, which makes the captured fringe patterns well-sinusoidal and alleviates the phase errors caused by the gamma nonlinearity. Compared with other gamma correction methods, only one captured pattern is needed to evaluate the gamma value without loss of the accuracy. With the proposed method, a fast and accurate three-dimensional shape measurement can be achieved using the conventional three-step phase-shifting algorithm. Experiments have verified its feasibility and validity.

  3. Alignment Measurements of the Microwave Anisotropy Probe (MAP) Instrument in a Thermal/Vacuum Chamber Using Photogrammetry

    NASA Technical Reports Server (NTRS)

    Hill, Michael D.; Herrera, Acey A.; Crane, J. Allen; Packard, Edward A.; Aviado, Carlos; Sampler, Henry P.; Obenschain, Arthur (Technical Monitor)

    2000-01-01

    The Microwave Anisotropy Probe (MAP) Observatory, scheduled for a late 2000 launch, is designed to measure temperature fluctuations (anisotropy) and produce a high sensitivity and high spatial resolution (< 0.3 deg at 90 GHz.) map of the cosmic microwave background (CMB) radiation over the entire sky between 22 and 90 GHz. MAP utilizes back-to-back Gregorian telescopes to focus the microwave signals into 10 differential microwave receivers, via 20 feed horns. Proper alignment of the telescope reflectors and the feed horns at the operating temperature of 90 K is a critical element to ensure mission success. We describe the hardware and methods used to validate the displacement/deformation predictions of the reflectors and the microwave feed horns during thermal/vacuum testing of the reflectors and the microwave instrument. The smallest deformations to be resolved by the measurement system were on the order of +/- 0.030 inches (0.762 mm). Performance of these alignment measurements inside a thermal/vacuum chamber with conventional alignment equipment posed several limitations. A photogrammetry (PG) system was chosen to perform the measurements since it is a non-contact measurement system, the measurements can be made relatively quickly and accurately, and the photogrammetric camera can be operated remotely. The hardware and methods developed to perform the MAP alignment measurements using PG proved to be highly successful. The PG measurements met the desired requirements, enabling the desired deformations to be measured and even resolved to an order of magnitude smaller than the imposed requirements. Viable data were provided to the MAP Project for a full analysis of the on-orbit performance of the Instrument's microwave system.

  4. Factors influencing in situ gamma-ray measurements

    NASA Astrophysics Data System (ADS)

    Loonstra, E. H.; van Egmond, F. M.

    2009-04-01

    Introduction In situ passive gamma-ray sensors are very well suitable for mapping physical soil properties. In order to make a qualitative sound soil map, high quality input parameters for calibration are required. This paper will focus on the factors that affect the output of in situ passive gamma-ray sensors, the primary source, soil, not taken into account. Factors The gamma-ray spectrum contains information of naturally occurring nuclides 40K, 238U and 232Th and man-made nuclides like 137Cs, as well as the total count rate. Factors that influence the concentration of these nuclides and the count rate can be classified in 3 categories. These are sensor design, environmental conditions and operational circumstances. Sensor design The main elements of an in situ gamma-ray sensor that influence the outcome and quality of the output are the crystal and the spectrum analysis method. Material and size of the crystal determine the energy resolution. Though widely used, NaI crystals are not the most efficient capturer of gamma radiation. Alternatives are BGO and CsI. BGO has a low peak resolution, which prohibits use in cases where man-made nuclides are subject of interest. The material is expensive and prone to temperature instability. CsI is robust compared to NaI and BGO. The density of CsI is higher than NaI, yielding better efficiency, especially for smaller crystal sizes. More volume results in higher energy efficiency. The reduction of the measured spectral information into concentration of radionuclides is mostly done using the Windows analysis method. In Windows, the activities of the nuclides are found by summing the intensities of the spectrum found in a certain interval surrounding a peak. A major flaw of the Windows method is the limited amount of spectral information that is incorporated into the analysis. Another weakness is the inherent use of ‘stripping factors' to account for contributions of radiation from nuclide A into the peak of nuclide B. This

  5. Measuring (13)C/(15)N chemical shift anisotropy in [(13)C,(15)N] uniformly enriched proteins using CSA amplification.

    PubMed

    Hung, Ivan; Ge, Yuwei; Liu, Xiaoli; Liu, Mali; Li, Conggang; Gan, Zhehong

    2015-11-01

    Extended chemical shift anisotropy amplification (xCSA) is applied for measuring (13)C/(15)N chemical shift anisotropy (CSA) of uniformly labeled proteins under magic-angle spinning (MAS). The amplification sequence consists of a sequence of π-pulses that repetitively interrupt MAS averaging of the CSA interaction. The timing of the pulses is designed to generate amplified spinning sideband manifolds which can be fitted to extract CSA parameters. The (13)C/(13)C homonuclear dipolar interactions are not affected by the π-pulses due to the bilinear nature of the spin operators and are averaged by MAS in the xCSA experiment. These features make the constant evolution-time experiment suitable for measuring CSA of uniformly labeled samples. The incorporation of xCSA with multi-dimensional (13)C/(15)N correlation is demonstrated with a GB1 protein sample as a model system for measuring (13)C/(15)N CSA of all backbone (15)NH, (13)CA and (13)CO sites. PMID:26404770

  6. Azadioxatriangulenium: exploring the effect of a 20 ns fluorescence lifetime in fluorescence anisotropy measurements

    NASA Astrophysics Data System (ADS)

    Bogh, Sidsel A.; Bora, Ilkay; Rosenberg, Martin; Thyrhaug, Erling; Laursen, Bo W.; Just Sørensen, Thomas

    2015-12-01

    Azaoxatriangulenium (ADOTA) has been shown to be highly emissive despite a moderate molar absorption coefficient of the primary electronic transition. As a result, the fluorescence lifetime is ~20 ns, longer than all commonly used red fluorescent organic probes. The electronic transitions in ADOTA are highly polarised (r 0  =  0.38), which in combination with the long fluorescence lifetime extents the size-range of biomolecular weights that can be detected in fluorescence polarisation-based experiments. Here, the rotational dynamics of bovine serum albumin (BSA) are monitored with three different ADOTA derivatives, differing only in constitution of the reactive linker. A detailed study of the degree of labelling, the steady-state anisotropy, and the time-resolved anisotropy of the three different ADOTA-BSA conjugates are reported. The fluorescence quantum yields (ϕ fl) of the free dyes in PBS solution are determined to be ~55%, which is reduced to ~20% in the ADOTA-BSA conjugates. Despite the reduction in ϕ fl, a ~20 ns intensity averaged lifetime is maintained, allowing for the rotational dynamics of BSA to be monitored for up to 100 ns. Thus, ADOTA can be used in fluorescence polarisation assays to fill the gap between commonly used organic dyes and the long luminescence lifetime transition metal complexes. This allows for efficient steady-state fluorescence polarisation assays for detecting binding of analytes with molecular weights of up to 100 kDa.

  7. MEASUREMENT OF THE ANISOTROPY OF COSMIC RAY ARRIVAL DIRECTIONS WITH ICECUBE

    SciTech Connect

    IceCube Collaboration; Abbasi, R.

    2010-05-17

    We report the first observation of an anisotropy in the arrival direction of cosmic rays with energies in the multi TeV region in the Southern sky using data from the IceCube detector. Between June 2007 and March 2008, the partially-deployed IceCube detector was operated in a configuration with 1320 digital optical sensors distributed over 22 strings at depths between 1450 and 2450 meters inside the Antarctic ice. IceCube is a neutrino detector, but the data are dominated by a large background of cosmic ray muons. Therefore, the background data are suitable for high-statistics studies of cosmic rays in the Southern sky. The data include 4.3 billion muons produced by downgoing cosmic ray interactions in the atmosphere; these events were reconstructed with a median angular resolution of 3 degrees and a median energy of ~;; 20 TeV. Their arrival direction distribution exhibits an anisotropy in right ascension with a first harmonic amplitude of (6.4 +- 0.2 stat. +- 0.8 syst.) x 10-4.

  8. Models for gamma-ray holdup measurements at duct contact

    SciTech Connect

    Sheppard, G.A.; Russo, P.A.; Wenz, T.R.; Miller, M.C.; Piquette, E.C. ); Haas, F.X.; Glick, J.B.; Garrett, A.G. )

    1991-01-01

    The use of gamma-ray measurements to nondestructively assay special nuclear material holdup in DOE processing facilities has increased recently. A measurement approach that is relatively insensitive to deposit geometry involves withdrawing the detector from the holdup-bearing equipment far enough to validate an assumed point-, line-, or area-source deposit geometry. Because of facility constraints, these generalized geometry procedures are not always followed, and some ducts are measured at contact. Quantitative interpretation of contact measurements requires knowledge of the width of the deposit transverse to the duct axis. Rocky Flats personnel have introduced a method to obtain data from which this width can be deduced. It involves taking measurements in pairs, with the detector viewing the holdup deposit at contact from above and below the duct. The interpretation of the top and bottom measurements to give the deposit width at each location requires a model for the detector's response to radial source position and a model for the deposit geometry. We have derived a relationship between the top-to-bottom count rate ratio and the deposit width that approximates the detector response and models the deposit geometry as a uniform strip. The model was validated in controlled experiments that used thin foils of high-enriched uranium metal to simulate duct deposits. 4 refs., 5 figs., 1 tab.

  9. Measuring Cosmological Parameters with Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    Amati, Lorenzo; Valle, Massimo Della

    2015-01-01

    Gamma-Ray Bursts (GRB) emit in a few dozen of seconds up to ~1054 erg, in terms of isotropic equivalent radiated energy Eiso, therefore they can be observed up to z ~ 10 and appear very promising tools to describe the expansion rate history of the Universe. In this paper we review the use of the Ep,i-Eiso correlation of Gamma-Ray Bursts to measure ΩM. We show that the present data set of GRBs, coupled with the assumption that we live in a flat universe, can provide indipendent evidence, from other probes, that ΩM~0.3. We show that current (e.g., Swift, Fermi/GBM, Konus-WIND) and next GRB experiments (e.g., CALET/GBM, SVOM, Lomonosov/UFFO, LOFT/WFM) will allow us, within a few years, to constrain ΩM and the evolution of dark energy with time, with an accuracy comparable to that currently exhibited by SNe-Ia.

  10. 137 Ba Double Gamma Decay Measurement with GAMMASPHERE

    DOE PAGESBeta

    Merchán, E.; Moran, K.; Lister, C. J.; Chowdhury, P.; McCutchan, E. A.; Greene, J. P.; Zhu, S.; Lauritsen, T.; Carpenter, M. P.; Shearman, R.

    2015-05-28

    The study of the electromagnetic moments (EM), and decay probability, provides detailed information about nuclear wave functions. The well-know properties of EM interactions are good for extracting information about the motion of nucleons. Higher order EM processes always occur, but are usually too weak to be measured. In the case of a 0+ → 0+ transitions, where a single gamma transition is forbidden, the simultaneous emission of two γ-rays has been studied. An interesting opportunity to further investigate 2-photon emission phenomena is by using a standard 137Cs source populating, via β-decay, the Jπ = 11/2- isomeric state at 662 keVmore » in 137Ba. In this case, two photon process can have contributions from quadrupole-quadrupole or dipole-octupole multipolarities in direct competition with the high multipolarity M4 decay. Since the yield of the double gamma decay is around six orders of magnitude less than the first order transition, very good statistics are needed in order to observe the phenomena and great care must be taken to suppress the first-order decay. The Gammasphere array is ideal since its configuration allows a good coverage of the angular distribution and the Compton events can be suppressed. Nevertheless the process to understand and eliminate the Compton background is a challenge. Geant4 simulations were carried out to help understand and correct for those factors.« less

  11. 137 Ba Double Gamma Decay Measurement with GAMMASPHERE

    SciTech Connect

    Merchán, E.; Moran, K.; Lister, C. J.; Chowdhury, P.; McCutchan, E. A.; Greene, J. P.; Zhu, S.; Lauritsen, T.; Carpenter, M. P.; Shearman, R.

    2015-05-28

    The study of the electromagnetic moments (EM), and decay probability, provides detailed information about nuclear wave functions. The well-know properties of EM interactions are good for extracting information about the motion of nucleons. Higher order EM processes always occur, but are usually too weak to be measured. In the case of a 0+ → 0+ transitions, where a single gamma transition is forbidden, the simultaneous emission of two γ-rays has been studied. An interesting opportunity to further investigate 2-photon emission phenomena is by using a standard 137Cs source populating, via β-decay, the Jπ = 11/2- isomeric state at 662 keV in 137Ba. In this case, two photon process can have contributions from quadrupole-quadrupole or dipole-octupole multipolarities in direct competition with the high multipolarity M4 decay. Since the yield of the double gamma decay is around six orders of magnitude less than the first order transition, very good statistics are needed in order to observe the phenomena and great care must be taken to suppress the first-order decay. The Gammasphere array is ideal since its configuration allows a good coverage of the angular distribution and the Compton events can be suppressed. Nevertheless the process to understand and eliminate the Compton background is a challenge. Geant4 simulations were carried out to help understand and correct for those factors.

  12. Branching Fraction Measurements of B+ to rho+ gamma,B0 to rho0 gamma, and B0 to omega gamma

    SciTech Connect

    Aubert, B.

    2007-01-03

    The authors present a study of the decays B{sup +} {yields} {rho}{sup +}{gamma}, B{sup 0} {yields} {rho}{sup 0}{gamma}, and B{sup 0} {yields} {omega}{gamma}. The analysis is based on data containing 347 million B{bar B} events recorded with the BABAR detector at the PEP-II asymmetric B factory. They measure the branching fractions {Beta}(B{sup +} {yields} {rho}{sup +}{gamma}) = (1.10{sub -0.33}{sup +0.37} {+-} 0.09) x 10{sup -6} and {Beta}(B{sup 0} {yields} {rho}{sup 0}{gamma}) = (0.79{sub -0.20}{sup +0.22} {+-} 0.06) x 10{sup -6}, and set a 90% C.L. upper limit {Beta}(B{sup 0} {yields} {omega}{gamma}) < 0.78 x 10{sup -6}. They also measure the isospin-averaged branching fraction {Beta}[B {yields} ({rho}/{omega}){gamma}] = (1.25{sub -0.24}{sup +0.25} {+-} 0.09) x 10{sup -6}, from which they determine |V{sub td}/V{sub ts}| = 0.200{sub -0.020}{sup +0.021} {+-} 0.015, where the first uncertainty is experimental and the second is theoretical.

  13. Measurement and modelling of moisture-electrical resistivity relationship of fine-grained unsaturated soils and electrical anisotropy

    NASA Astrophysics Data System (ADS)

    Merritt, A. J.; Chambers, J. E.; Wilkinson, P. B.; West, L. J.; Murphy, W.; Gunn, D.; Uhlemann, S.

    2016-01-01

    A methodology for developing resistivity-moisture content relationships of materials associated with a clayey landslide is presented. Key elements of the methodology include sample selection and preparation, laboratory measurement of resistivity with changing moisture content, and the derivation of models describing the relationship between resistivity and moisture content. Laboratory resistivity measurements show that the techniques utilised (samples and square array) have considerable potential as a means of electropetrophysical calibration of engineering soils and weak rock. Experimental electrical resistivity results show a hierarchy of values dependent on sample lithology, with silty clay exhibiting the lowest resistivities, followed by siltstones and sands, which return the highest resistivities. In addition, finer grained samples show a greater degree of anisotropy between measurement orientations than coarser grained samples. However, suitability of results in light of issues such as sample cracking and electrical conduction must be identified and accounted for if the results are to be accurately up-scaled to inverted model resistivity results. The existence of directional anisotropy makes model calibration curve selection more difficult due to variability in the range of measured laboratory resistances. The use of larger measurement array size means that experimental data will be more representative of bulk lithological properties. In addition, use of electrodes with a relatively high surface area (wide diameter) help maintain low contact resistances and repeat measurement error, relative to narrow electrodes. Variation exists between the fit of experimental data and petrophysical models. Model fit is best for clay-dominated samples but fits less well for sand-dominated samples. Waxman-Smits equation is appropriately applied in this investigation as all samples have considerable clay mineral content, as is shown in non-negligible CEC results. The

  14. Measurements of the anisotropy of the cosmic background radiation at 0.5 deg scale near the star Mu Pegasi

    NASA Technical Reports Server (NTRS)

    Meinhold, P.; Clapp, A.; Devlin, M.; Fischer, M.; Gundersen, J.; Holmes, W.; Lange, A.; Lubin, P.; Richards, P.; Smoot, G.

    1993-01-01

    Results are presented from the third flight of the MAX experiment, an attitude-controlled balloon-borne millimeter-wave telescope with a 0.5 deg beam, a 1 deg chop, and a three-channel bolometric photometer. Several hours of high-quality data were obtained during a flight on 1991 June 5, including long integrations to search for CBR anisotropy, two separate measurements of dust in the Galactic plane, a brief scan of the Coma Cluster to search for the Sunyaev-Zel'dovich (SZ) effect, and a number of important systematic tests. Data from one of the long CBR integrations, carried out in a region of sky near the star Mu Pegasi, are presented. The primary structure in the data is shown to be emission from Galactic dust via its spectrum and correlation with the IRAS 100/micron map. Several approaches are used to fit this dust component and remove it from the data. An upper limit to CBR anisotropy of deltaT/T less than 2.5 x 10 exp -5 is obtained for a Gaussian autocorrelation function with coherence angle omega(c) = 25'. This limit is significantly higher than the measurement sensitivity of deltaT/T about 1 x 10 exp -5 due to the presence of residual structure in the data after removal of the dust component.

  15. Measurement of gamma field parameters in core with LEU fuel IRT-4M using TL detectors

    SciTech Connect

    Bily, T.

    2008-07-15

    Thermoluminescent dosimeters represent very useful tool for gamma fields parameters measurements at nuclear research reactors, especially at zero power ones. {sup 7}LiF:Mg,Ti and {sup 7}LiF:Mg,Cu,P type TL dosimeters enable determination of only gamma component in mixed neutron - gamma field. At VR-1 reactor operated within the Faculty of Nuclear Sciences and Physical Engineering at the Czech Technical University in Prague the integral characteristics of gamma rays field were investigated, especially its spatial distribution and time behaviour, i.e. the non-saturated delayed gamma ray emission influence. Measured spatial distributions were compared with monte carlo code MCNP5 calculations. Although MCNP cannot generate delayed gamma rays from fission, the relative gamma dose rate distribution is within {+-} 15% with measured values. The experiments were carried out with core configuration C1 consisting of LEU fuel IRT-4M (19.7 %). (author)

  16. Theoretical, numerical and experimental study of geometrical parameters that affect anisotropy measurements in polarization-resolved SHG microscopy.

    PubMed

    Teulon, Claire; Gusachenko, Ivan; Latour, Gaël; Schanne-Klein, Marie-Claire

    2015-04-01

    Polarization-resolved second harmonic generation (P-SHG) microscopy is an efficient imaging modality for in situ observation of biopolymers structure in tissues, providing information about their mean in-plane orientation and their molecular structure and 3D distribution. Nevertheless, P-SHG signal build-up in a strongly focused regime is not throroughly understood yet, preventing reliable and reproducible measurements. In this study, theoretical analysis, vectorial numerical simulations and experiments are performed to understand how geometrical parameters, such as excitation and collection numerical apertures and detection direction, affect P-SHG imaging in homogeneous collagen tissues. A good agreement is obtained in tendon and cornea, showing that detection geometry significantly affects the SHG anisotropy measurements, but not the measurements of collagen in-plane orientation. PMID:25968762

  17. 102Pd(n, {gamma}) Cross Section Measurement Using DANCE

    SciTech Connect

    Hatarik, R.; Alpizar-Vicente, A. M.; Bredeweg, T. A.; Esch, E.-I.; Haight, R. C.; O'Donnell, J. M.; Reifarth, R.; Rundberg, R. S.; Ullmann, J. L.; Vieira, D. J.; Wouters, J. M.; Greife, U.

    2006-03-13

    The neutron capture cross section of the proton rich nucleus 102Pd was measured with the Detector for Advanced Neutron Capture Experiments (DANCE) at the Los Alamos Neutron Science Center. The target was a 2 mg Pd foil with 78% enriched 102Pd. It was held by a 0.9 {mu}m thick Mylar bag which was selected after comparing different thicknesses of Kapton and Mylar for their scattering background. To identify the contribution of the other Pd isotopes the data of a natural Pd sample was compared to the data of the 102Pd enriched sample. A 12C sample was used to determine the scattering background. The 102Pd(n, {gamma}) rate is of importance for the p-process nucleosynthesis.

  18. Measurement of the Branching Ratios Gamma(D*+s -> D+s pi0)/Gamma(D*+s ->D+s gamma) and Gamma(D*0 ->D0 pi0)/Gamma(D*0 -> D0gamma)

    SciTech Connect

    Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; Grauges, E.; Palano, A.; Pappagallo, M.; Pompili, A.; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; Eigen, G.; Ofte, I.; Stugu, B. /Bergen U. /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /Ferrara U. /INFN, Ferrara /Frascati /Genoa U. /INFN, Genoa /Harvard U. /Heidelberg U. /Imperial Coll., London /Iowa U. /Iowa State U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS /McGill U. /Milan U. /INFN, Milan /Mississippi U. /Montreal U. /Mt. Holyoke Coll. /Naples U. /INFN, Naples /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /Paris U., VI-VII /Pennsylvania U. /Perugia U. /INFN, Perugia /Pisa U. /Pisa, Scuola Normale Superiore /INFN, Pisa /Prairie View A-M /Princeton U. /Rome U. /INFN, Rome /Rostock U. /Rutherford /DAPNIA, Saclay /South Carolina U. /SLAC /Stanford U., Phys. Dept. /SUNY, Albany /Tennessee U. /Texas U. /Texas U., Dallas /Turin U. /INFN, Turin /Trieste U. /INFN, Trieste /Valencia U., IFIC /Vanderbilt U. /Victoria U. /Warwick U. /Wisconsin U., Madison /Yale U.

    2005-08-23

    Data samples corresponding to the isospin-violating decay D*{sub s}{sup +} {yields} D{sub s}{sup +}{pi}{sup 0} and the decays D*{sub s}{sup +} {yields} D{sub s}{sup +}, D*{sup 0} {yields} D{sup 0}{pi}{sup 0} and D*{sup 0} {yields} D{sup 0}{gamma} are reconstructed using 90.4 fb{sup -1} of data recorded by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider. The following branching ratios are extracted: {Lambda}(D*{sub s}{sup +} {yields} D{sub s}{sup +}{pi}{sup 0})/{Lambda}(D*{sub s}{sup +} {yields} D{sub s}{sup +}{gamma}) = 0.062 {+-} 0.005(stat.) {+-} 0.006(syst.) and {Lambda}(D*{sup 0} {yields} D{sup 0}{pi}{sup 0})/{Lambda}(D*{sup 0} {yields} D{sup 0}{gamma}) = 1.74 {+-} 0.02(stat.) {+-} 0.13(syst.). Both measurements represent significant improvements over present world averages.

  19. On the Determination of Transition-Moment Directions from Absorption Anisotropy Measurements

    NASA Astrophysics Data System (ADS)

    Kawski, A.; Gryczyński, Z.

    1987-06-01

    A formula is derived for the absorption anisotropy K = (A∥ - A⊥) / (A∥ + 2A⊥ ) (where A∥ and A⊥ are the absorbances parallel and perpendicular to the stretching direction of the polymer film, respectively) as a function of the stretch ratio, Rs, of the film and the angle φ between the absorption transition moment direction and the long axis of a prolate molecule. Employing this relation, absolute transition moment directions (the angles φ) were determined experimentally for the following compounds: 1.8-diphenyloctatetraene (DPO), 1,6-diphenylhexatriene (DPH), 1.4-diphenylbutadiene (DPB), 4-dimethylamino-4'-nitrostilbene (DNS), 4-dimethylamino- 4'-chlorostilbene (DCIS) and p-terphenyl (TP). The directions were found to be along the long molecular axis in the long-wave absorption band. Small deviations of the angles obtained from (φ= 0°, which were of the order of several degrees, are due to the incomplete linearity of the molecules under investigation.

  20. EGAF: Measurement and Analysis of Gamma-ray Cross Sections

    NASA Astrophysics Data System (ADS)

    Firestone, R. B.; Abusaleem, K.; Basunia, M. S.; Bečvář, F.; Belgya, T.; Bernstein, L. A.; Choi, H. D.; Escher, J. E.; Genreith, C.; Hurst, A. M.; Krtička, M.; Renne, P. R.; Révay, Zs.; Rogers, A. M.; Rossbach, M.; Siem, S.; Sleaford, B.; Summers, N. C.; Szentmiklosi, L.; van Bibber, K.; Wiedeking, M.

    2014-05-01

    The Evaluated Gamma-ray Activation File (EGAF) is the result of a 2000-2007 IAEA Coordinated Research Project to develop a database of thermal, prompt γ-ray cross sections, σγ, for all elemental and selected radioactive targets. No previous database of this kind had existed. EGAF was originally based on measurements using guided neutron beams from the Budapest Reactor on all elemental targets from Z=1-82, 90 and 92, except for He and Pm. The EGAF σγ data were published in the Database of Prompt Gamma Rays from Slow Neutron Capture for Elemental Analysis [1]. An international collaboration has formed to continue the EGAF measurements with isotopically enriched targets, derive total radiative thermal neutron cross sections, σ0, extend the σγ data from thermal to 20 MeV neutrons, compile a completed activation data file, improve sections of the Reference Input Parameter Library (RIPL) with more complete and up to date level and γ-ray data, evaluate statistical γ-ray data from reaction studies, and determine recommended neutron separations energies, Sn, for atomic mass evaluations. A new guided neutron beam facility has become available at the Garching (Munich) FRM II Reactor, and high energy neutron experimental facilities are being developed by a Berkeley area collaboration where 5-33 MeV neutron beams are available at the LBNL 88” cyclotron, 2.5 and 14 MeV beams at the University of California, Berkeley neutron generator laboratory, and high flux, 10 nṡcmṡ-2 s-1, neutron pulses available from the LLNL National Ignition Facility (NIF).

  1. 241Am (n,gamma) isomer ratio measurement

    SciTech Connect

    Bond, Evelyn M; Vieira, David J; Moody, Walter A; Slemmons, Alice K

    2011-01-05

    The objective of this project is to improve the accuracy of the {sup 242}Cm/{sup 241}Am radiochemistry ratio. We have performed an activation experiment to measure the {sup 241}Am(n,{gamma}) cross section leading to either the ground state of {sup 242g}Am (t{sub 1/2} = 16 hr) which decays to {sup 242}Cm (t{sub 1/2} = 163 d) or the long-lived isomer {sup 242m}Am (t{sub 1/2} = 141 yr). This experiment will develop a new set of americium cross section evaluations that can be used with a measured {sup 242}Cm/{sup 241}Am radiochemical measurement for nuclear forensic purposes. This measurement is necessary to interpret the {sup 242}Cm/{sup 241}Am ratio because a good measurement of this neutron capture isomer ratio for {sup 241}Am does not exist. The targets were prepared in 2007 from {sup 241}Am purified from LANL stocks. Gold was added to the purified {sup 241}Am as an internal neutron fluence monitor. These targets were placed into a holder, packaged, and shipped to Forschungszentrum Karlsruhe, where they were irradiated at their Van de Graff facility in February 2008. One target was irradiated with {approx}25 keV quasimonoenergetic neutrons produced by the {sup 7}Li(p,n) reaction for 3 days and a second target was also irradiated for 3 days with {approx}500 keV neutrons. Because it will be necessary to separate the {sup 242}Cm from the {sup 241}Am in order to measure the amount of {sup 242}Cm by alpha spectrometry, research into methods for americium/curium separations were conducted concurrently. We found that anion exchange chromatography in methanol/nitric acid solutions produced good separations that could be completed in one day resulting in a sample with no residue. The samples were returned from Germany in July 2009 and were counted by gamma spectrometry. Chemical separations have commenced on the blank sample. Each sample will be spiked with {sup 244}Cm, dissolved and digested in nitric acid solutions. One third of each sample will be processed at a time

  2. Magnetic multilayer interface anisotropy

    SciTech Connect

    Pechan, M.J.

    1992-01-01

    Ni/Mo and Ni/V multilayer magnetic anisotropy has been investigated as a function of Ni layer thickness, frequency and temperature. Variable frequency ferromagnetic resonance (FMR) measurements show, for the first time, significant frequency dependence associated with the multilayer magnetic anisotropy. The thickness dependence allows one to extract the interface contribution from the total anisotropy. Temperature dependent FMR (9 GHz) and room temperature magnetization indicate that strain between Ni and the non-magnetic layers is contributing significantly to the source of the interface anisotropy and the state of the interfacial magnetization. In order to examine the interface properties of other transition metal multilayer systems, investigations on Fe/Cu are underway and CoCr/Ag is being proposed. ESR measurements have been reported on Gd substituted YBaCuO superconductors and a novel quasi-equilibrium method has been developed to determine quickly and precisely the ransition temperature.

  3. In-flight measurements of Terrestrial Gamma-Rays

    NASA Astrophysics Data System (ADS)

    van Deursen, Alexander; Kochkin, Pavlo; de Boer, Alte; Bardet, Michiel; Boissin, Jean-Francois

    2014-05-01

    Thunderstorms emit bursts of energetic radiation. Moreover, lightning stepped leader produces X-ray pulses. The phenomena, their interrelation and impact on Earth's atmosphere and near space are not fully understood yet. In-flight Lightning Strike Damage Assessment System ILDAS is developed in a EU FP6 project ( http://ildas.nlr.nl/ ) to provide information on threat that lightning poses to aircraft. It consists of 2 E-field sensors, and a varying number of H-field sensors. It has recently been modified to include two LaBr3 scintillation detectors. The scintillation detectors are sensitive to x- and gamma-rays above 30 keV. The entire system is installed on A-350 aircraft and digitizes data with 100 MSamples/sec rate when triggered by lightning. A continuously monitoring channel counts the number of occurrences that the X-ray signal exceeds a set of trigger levels. In the beginning of 2014 the aircraft flies through thunderstorm cells collecting the data from the sensors. The X-rays generated by the lightning flash are measured in synchronization with the lightning current information during a period of 1 second around the strike. The continuous channel stores x-ray information with less time and amplitude resolution during the whole flight. That would allow x-rays from TGFs and continuous gamma-ray glow of thundercloud outside that 1 s time window. We will give an overview of the ILDAS system and show that the X-ray detection works as intended. The availability of the lightning associated data depends on the flight schedule. If available, these data will be discussed at the conference.

  4. Fission prompt gamma-ray multiplicity distribution measurements and simulations at DANCE

    SciTech Connect

    Chyzh, A; Wu, C Y; Ullmann, J; Jandel, M; Bredeweg, T; Couture, A; Norman, E

    2010-08-24

    The nearly energy independence of the DANCE efficiency and multiplicity response to {gamma} rays makes it possible to measure the prompt {gamma}-ray multiplicity distribution in fission. We demonstrate this unique capability of DANCE through the comparison of {gamma}-ray energy and multiplicity distribution between the measurement and numerical simulation for three radioactive sources {sup 22}Na, {sup 60}Co, and {sup 88}Y. The prospect for measuring the {gamma}-ray multiplicity distribution for both spontaneous and neutron-induced fission is discussed.

  5. Low level measurement of (60)Co by gamma ray spectrometry using γ-γ coincidence.

    PubMed

    Paradis, H; de Vismes Ott, A; Luo, M; Cagnat, X; Piquemal, F; Gurriaran, R

    2016-03-01

    This paper presents the latest development of the laboratory to measure the natural and artificial massic activities in environmental samples. The measurement method of coincident emitters by gamma-gamma coincidence using an anti-Compton device and its digital electronics is described. Results obtained with environmental samples are shown. Despite its low efficiency, this method decreases detection limits of (60)Co for certain samples compared to conventional gamma-ray spectrometry due to its very low background. PMID:26682892

  6. COBRAS/SAMBA: the ESA Medium Size Mission for measurements of CBR anisotropy

    NASA Astrophysics Data System (ADS)

    Mandolesi, N.; Bersanelli, M.; Cesarsky, C.; Danese, L.; Efstathiou, G.; Griffin, M.; Lamarre, J. M.; Norgaard-Nielsen, H. U.; Pace, O.; Puget, J. L.; Raisanen, A.; Smoot, G. F.; Tauber, J.; Volonte, S.

    1995-02-01

    The COBRAS/SAMBA mission is designed for extensive, accurate mapping of the anisotropy of the Cosmic Background Radiation. with angular sensitivity from scales of a few arcminutes up to and overlapping with the > 7° COBE-DMR resolution. This will allow a full identification of the primordial density perturbations which grew to Corm the large-scale structures observed in the present universe. The COBRAS/SAMBA maps will provide a major source of information relevant to several cosmological and astrophysical issues, such as testing theories of the early universe and the origin of cosmic structure. One of the main diffuse foreground emissions will be from interstellar dust, and the mission will provide relevant information on its components and emission properties. A combination of bolometric and radiometric detection techniques will ensure the sensitivity and wide spectral coverage required for accurate foreground discrimination. A far-Earth orbit has been selected to minimize the unwanted emission from the Earth as a source of contamination. The project is currently undergoing a feasibility study within the European Space Agency M3 programme.

  7. Measurement of Arcminute Scale Cosmic Microwave Background Anisotropy with the BIMA Array

    NASA Technical Reports Server (NTRS)

    Dawson, K. S.; Holzapfel, W. L.; Carlstrom, J. E.; Joy, M.; LaRoque, S. J.; Miller, A.; Nagai, D.; Six, N. Frank (Technical Monitor)

    2002-01-01

    We report the results of our continued study of arcminute scale anisotropy in the Cosmic Microwave Background (CMB) with the Berkeley-Illinois-Maryland Association (BIMA) array. The survey consists of ten independent fields selected for low infrared dust emission and lack of bright radio point sources. With observations from the VLA (Very Large Array) at 4.8 GHz, we have identified point sources which could act as contaminants in estimates of the CMB power spectrum and removed them in the analysis. Modeling the observed power spectrum with a single. flat band power with average multipole of l(sub eff) = 6864, we find Delta T = 14.2((sup +4.8)(sub -6.0)) micro K at 68% confidence. The signal in the visibility data exceeds the expected contribution from instrumental noise with 96.5% confidence. We have also divided the data into two bins corresponding to different spatial resolutions in the power spectrum. We find Delta T(sub 1) = 16.6((sup +5.3)(sub -5.9)) micro K at 68% confidence for CMB flat band power described by an average multipole of l(sub eff) = 5237 and Delta T(sub 2) is less than 26.5 micro K at 95% confidence for l(sub eff) = 8748.

  8. Surface-tension-anisotropy measurements of succinonitrile and pivalic acid: Comparison with microscopic solvability theory

    SciTech Connect

    Muschol, M.; Liu, D.; Cummins, H.Z. )

    1992-07-15

    New determinations of the surface-tension-anisotropy parameter {var epsilon}{sub 4} of succinonitrile (SCN), pivalic acid (PVA), and a PVA--1%-ethanol mixture are reported. Effects of temperature gradients and crystal orientation are analyzed in detail. The experiments utilized numerical interpolation techniques previously employed by Dougherty and Gollub to enhance the digital image resolution. The values found for {var epsilon}{sub 4} in SCN, PVA, and PVA--1%-ethanol are 0.0055{plus minus}0.0015, 0.025{plus minus}0.002, and 0.026{plus minus}0.002, respectively. From these values, the selection parameter {sigma}{sub theor}{sup *} predicted by microscopic solvability theory for the three-dimensional axisymmetric case was computed and compared to the {sigma}{sub expt}{sup *} values determined directly from previous dendritic-growth experiments. We find that {sigma}{sub theor}{sup *}/{sigma}{sub expt}{sup *} is 0.56{plus minus}0.20 for SCN, and 2.14{plus minus}0.50 for PVA. Possible sources for these discrepancies are discussed.

  9. EuTEPC: measurements in gamma and neutron fields.

    PubMed

    Moro, D; Chiriotti, S

    2015-09-01

    The EuTEPC (European TEPC) is a novel spherical tissue-equivalent gas-proportional single-wire counter that has been designed and constructed at the National Laboratories of Legnaro of Italian Nuclear Physics Institute in collaboration with the University of Padova, the DLR (German Aerospace Centre) and Austrian Institute of Technology. Its peculiarity is the spherical A-150 cathode wall which is sub-divided in nine sectors. Each sector is properly and differently biased, in order to obtain a uniform electric field along the anode wire, for reaching a good isotropic response and energy resolution. The counter components can be easily replaced and reassembled including the anode wire. The counter could be used as a monitor area inside the International Space Station. This paper describes first microdosimetric measurements in (60)Co, (137)Cs and (241)Am-Be(α,n) gamma and neutron fields performed with the EuTEPC filled with pure propane gas. Measurements have been performed simulating sites sizes, ranging from 0.05 up to 0.25 mg cm(-2) in pure propane, which correspond from 0.7 up to 3.3 µm equivalent site sizes in propane-TE gas. Comparisons with some literature spectra are presented. PMID:25877529

  10. How to make robust splitting measurements for single-station analysis and three-dimensional imaging of seismic anisotropy

    NASA Astrophysics Data System (ADS)

    Monteiller, Vadim; Chevrot, Sébastien

    2010-07-01

    We quantify errors on splitting intensity measurements produced by incoherent noise on horizontal components through a detailed analysis of synthetic seismograms and of SKS and SKKS waves recorded by four permanent broad-band stations. We find that these errors are quite significant, even on high-quality records, because the measurement procedure involves the comparison of radial and transverse components, which are both contaminated by noise. To decrease the level of noise in the data, it is thus recommended to average splitting intensities from waves coming from the same backazimuth. Alternatively, one can analyse stacked radial and transverse components after applying a Wiener filter, which standardizes the waveforms. This is found to be equivalent because the measure of splitting intensity is a linear process. The utilization of Wiener filters reduces variations of apparent splitting resulting from differences in frequency content of the waveforms. It is possible to determine splitting parameters (splitting delays and fast directions) from azimuthal variations of splitting intensity at a particular station. Tests on synthetic seismograms demonstrate that this approach gives unbiased and robust estimates of splitting parameters, in contrast to the Silver and Chan method, which only works on the rare records that have very large signals on their transverse components. The Wolfe and Silver method does not suffer from this limitation and gives the same results as the multichannel splitting intensity method. Analysis of splitting intensities at stations BDFB, BGCA, CAN and ERM gives fast directions that are generally in excellent agreement with those determined with the Wolfe and Silver method. However, at some stations, azimuthal variations of splitting intensities reveal features that are not well captured by the sinusoidal variation representing the average anisotropy beneath the station. This suggests that small-scale lateral variations of anisotropy are present

  11. Prompt gamma radiation as a new tool to measure reactor power

    NASA Astrophysics Data System (ADS)

    jalali, Majid; Abdi, Mohammad Reza; davati, Mojtaba Mostajabod

    2013-10-01

    A new method, based on reactor prompt gamma radiation detection, for reactor power measurement is introduced and validated. To verify, the ex-core gamma radiation spectrum from the Iranian Heavy Water Zero Power Reactor (HWZPR) were measured by HPGe and NaI detectors each suitably positioned. The collective prompt gamma count rates for all or for a portion of each of 2″×2″ NaI detector spectra were obtained for seven power level readings from calibrated reactor power monitors. A good linear behavior was found between gamma count rate and reactor power. The method of calibrated prompt gamma reactor power determination is a stable and reliable tool, on-line, sensitive to sudden variation of power, working in pulse mode, increasing redundancy and diversity and so improving the reactor safety. The prompt gamma counting system can be adopted and installed in other nuclear reactors to measure power.

  12. Measurements of Separate Neutron and Gamma-Ray Coincidences with Liquid Scintillators and Digital PSD Technique

    SciTech Connect

    Flaska, Marek; Pozzi, Sara A

    2007-10-01

    A new technique is presented for the measurement of neutron and/or gamma-ray coincidences. Separate neutron neutron, neutron gamma-ray, gamma-ray neutron, and gamma-ray gamma-ray coincidences are acquired with liquid scintillation detectors and a digital pulse shape discrimination (PSD) technique based on standard charge integration method. The measurement technique allows for the collection of fast coincidences in a time window of the order of a few tens of nanoseconds between the coincident particles. The PSD allows for the acquisition of the coincidences in all particle combinations. The measurements are compared to results obtained with the MCNP-PoliMi code, which simulates neutron and gamma-ray coincidences from from a source on an event-by-event basis. This comparison leads to good qualitative agreement.

  13. Software for Control and Measuring Instrumentation of the GAMMA-400 Gamma-telescope Fast Scintillator Detector System

    NASA Astrophysics Data System (ADS)

    Naumov, P. P.; Naumov, P. Yu.; Runtso, M. F.; Solodovnikov, A. A.

    Currently, the final stage of the ground tests for the technological detector of the high-energy gamma-ray telescope (GRT) GAMMA-400 are finished. The new space GRT will accept the gamma-rays with energy more than 400 MeV and is aimed to open our eyes for so-called "dark matter" problem in the Universe. The high-speed scintillation detectors system (SDS) is used one of the main GRT particle detectors and the good ground test measurements will let the future space mission to get the reliable data. This paper describes the software and hardware of the laboratory control and calibration systems for physical measurements of GRT STDS properties.

  14. Branching fraction measurements of B+-->rho+gamma, B0-->rho0gamma, and B0-->omegagamma.

    PubMed

    Aubert, B; Bona, M; Boutigny, D; Karyotakis, Y; Lees, J P; Poireau, V; Prudent, X; Tisserand, V; Zghiche, A; Grauges, E; Palano, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Battaglia, M; Brown, D N; Button-Shafer, J; Cahn, R N; Groysman, Y; Jacobsen, R G; Kadyk, J A; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lopes Pegna, D; Lynch, G; Mir, L M; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Tackmann, K; Wenzel, W A; del Amo Sanchez, P; Barrett, M; Harrison, T J; Hart, A J; Hawkes, C M; Watson, A T; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schroeder, T; Steinke, M; Boyd, J T; Burke, J P; Cottingham, W N; Walker, D; Asgeirsson, D J; Cuhadar-Donszelmann, T; Fulsom, B G; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Khan, A; Kyberd, P; Saleem, M; Sherwood, D J; Teodorescu, L; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Todyshev, K Yu; Bondioli, M; Bruinsma, M; Chao, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M; Martin, E C; Stoker, D P; Abachi, S; Buchanan, C; Foulkes, S D; Gary, J W; Liu, F; Long, O; Shen, B C; Zhang, L; Hill, E J; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Kovalskyi, D; Richman, J D; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Schalk, T; Schumm, B A; Seiden, A; Williams, D C; Wilson, M G; Winstrom, L O; Chen, E; Cheng, C H; Dvoretskii, A; Fang, F; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Mancinelli, G; Meadows, B T; Mishra, K; Sokoloff, M D; Blanc, F; Bloom, P C; Chen, S; Ford, W T; Hirschauer, J F; Kreisel, A; Nagel, M; Nauenberg, U; Olivas, A; Smith, J G; Ulmer, K A; Wagner, S R; Zhang, J; Chen, A; Eckhart, E A; Soffer, A; Toki, W H; Wilson, R J; Winklmeier, F; Zeng, Q; Altenburg, D D; Feltresi, E; Hauke, A; Jasper, H; Merkel, J; Petzold, A; Spaan, B; Wacker, K; Brandt, T; Klose, V; Lacker, H M; Mader, W F; Nogowski, R; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Volk, A; Bernard, D; Bonneaud, G R; Latour, E; Thiebaux, Ch; Verderi, M; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Robertson, A I; Xie, Y; Andreotti, M; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Petrella, A; Piemontese, L; Prencipe, E; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Pacetti, S; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Buzzo, A; Contri, R; Lo Vetere, M; Macri, M M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Chaisanguanthum, K S; Morii, M; Wu, J; Dubitzky, R S; Marks, J; Schenk, S; Uwer, U; Bard, D J; Dauncey, P D; Flack, R L; Nash, J A; Nikolich, M B; Panduro Vazquez, W; Behera, P K; Chai, X; Charles, M J; Mallik, U; Meyer, N T; Ziegler, V; Cochran, J; Crawley, H B; Dong, L; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gritsan, A V; Denig, A G; Fritsch, M; Schott, G; Arnaud, N; Davier, M; Grosdidier, G; Höcker, A; Lepeltier, V; Le Diberder, F; Lutz, A M; Pruvot, S; Rodier, S; Roudeau, P; Schune, M H; Serrano, J; Stocchi, A; Wang, W F; Wormser, G; Lange, D J; Wright, D M; Chavez, C A; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; Hutchcroft, D E; Payne, D J; Schofield, K C; Touramanis, C; Bevan, A J; George, K A; Di Lodovico, F; Menges, W; Sacco, R; Cowan, G; Flaecher, H U; Hopkins, D A; Jackson, P S; McMahon, T R; Salvatore, F; Wren, A C; Brown, D N; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Chia, Y M; Edgar, C L; Lafferty, G D; West, T J; Yi, J I; Chen, C; Hulsbergen, W D; Jawahery, A; Lae, C K; Roberts, D A; Simi, G; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Li, X; Moore, T B; Salvati, E; Saremi, S; Cowan, R; Koeneke, K; Lang, M I; Sciolla, G; Sekula, S J; Spitznagel, M; Taylor, F; Yamamoto, R K; Yi, M; Kim, H; McLachlin, S E; Patel, P M; Robertson, S H; Lazzaro, A; Lombardo, V; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Simard, M; Taras, P; Viaud, F B; Nicholson, H; Cavallo, N; De Nardo, G; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M A; Raven, G; Snoek, H L; Jessop, C P; Losecco, J M; Benelli, G; Corwin, L A; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Morris, J P; Rahimi, A M; Regensburger, J J; Ter-Antonyan, R; Wong, Q K; Blount, N L; Brau, J; Frey, R; Igonkina, O; Kolb, J A; Lu, M; Potter, C T; Rahmat, R; Sinev, N B; Strom, D; Strube, J; Torrence, E; Gaz, A; Margoni, M; Morandin, M; Pompili, A; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Ben-Haim, E; Briand, H; Chauveau, J; David, P; Del Buono, L; de la Vaissière, Ch; Hamon, O; Hartfiel, B L; Leruste, Ph; Malclès, J; Ocariz, J; Gladney, L; Biasini, M; Covarelli, R; Angelini, C; Batignani, G; Bettarini, S; Calderini, G; Carpinelli, M; Cenci, R; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Mazur, M A; Morganti, M; Neri, N; Paoloni, E; Rizzo, G; Walsh, J J; Haire, M; Biesiada, J; Elmer, P; Lau, Y P; Lu, C; Olsen, J; Smith, A J S; Telnov, A V; Bellini, F; Cavoto, G; D'Orazio, A; del Re, D; Di Marco, E; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Jackson, P D; Li Gioi, L; Mazzoni, M A; Morganti, S; Piredda, G; Polci, F; Voena, C; Ebert, M; Schröder, H; Waldi, R; Adye, T; Castelli, G; Franek, B; Olaiya, E O; Ricciardi, S; Roethel, W; Wilson, F F; Aleksan, R; Emery, S; Escalier, M; Gaidot, A; Ganzhur, S F; Hamel de Monchenault, G; Kozanecki, W; Legendre, M; Vasseur, G; Yèche, Ch; Zito, M; Chen, X R; Liu, H; Park, W; Purohit, M V; Wilson, J R; Allen, M T; Aston, D; Bartoldus, R; Bechtle, P; Berger, N; Claus, R; Coleman, J P; Convery, M R; Dingfelder, J C; Dorfan, J; Dubois-Felsmann, G P; Dujmic, D; Dunwoodie, W; Field, R C; Glanzman, T; Gowdy, S J; Graham, M T; Grenier, P; Halyo, V; Hast, C; Hryn'ova, T; Innes, W R; Kelsey, M H; Kim, P; Leith, D W G S; Li, S; Luitz, S; Luth, V; Lynch, H L; MacFarlane, D B; Marsiske, H; Messner, R; Muller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Pulliam, T; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Stelzer, J; Su, D; Sullivan, M K; Suzuki, K; Swain, S K; Thompson, J M; Va'vra, J; van Bakel, N; Wagner, A P; Weaver, M; Wisniewski, W J; Wittgen, M; Wright, D H; Wulsin, H W; Yarritu, A K; Yi, K; Young, C C; Burchat, P R; Edwards, A J; Majewski, S A; Petersen, B A; Wilden, L; Ahmed, S; Alam, M S; Bula, R; Ernst, J A; Jain, V; Pan, B; Saeed, M A; Wappler, F R; Zain, S B; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Ritchie, J L; Schilling, C J; Schwitters, R F; Izen, J M; Lou, X C; Ye, S; Bianchi, F; Gallo, F; Gamba, D; Pelliccioni, M; Bomben, M; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Lanceri, L; Vitale, L; Azzolini, V; Lopez-March, N; Martinez-Vidal, F; Oyanguren, A; Albert, J; Banerjee, Sw; Bhuyan, B; Hamano, K; Kowalewski, R; Nugent, I M; Roney, J M; Sobie, R J; Back, J J; Harrison, P F; Latham, T E; Mohanty, G B; Pappagallo, M; Band, H R; Chen, X; Dasu, S; Flood, K T; Hollar, J J; Kutter, P E; Mellado, B; Pan, Y; Pierini, M; Prepost, R; Wu, S L; Yu, Z; Neal, H

    2007-04-13

    We present a study of the decays B+-->rho+gamma, B0-->rho0gamma, and B0-->omegagamma. The analysis is based on data containing 347 x 10(6) BB[over ] events recorded with the BABAR detector at the PEP-II asymmetric B factory. We measure the branching fractions B(B+-->rho+)gamma)=(1.10_(-0.33)(+0.37)+/-0.09)x10(-6) and B(B0-->rho0gamma)=(0.79(-0.20)(+0.22)+/-0.06)x10(-6), and set a 90% C.L. upper limit B(B0-->omegagamma)<0.78 x 10(-6). We also measure the isospin-averaged branching fraction B(B-->(rho/omega)gamma)=(1.25(-0.24)(+0.25)+/-0.09)x10(-6), from which we determine |Vtd/Vts|=0.200(-0.020)(+0.021)+/-0.015, where the first uncertainty is experimental and the second is theoretical. PMID:17501336

  15. SH-SV Polarization Anisotropy:Interpretation of Experimentally Measured Love and Rayleigh Wave Phase Velocities

    NASA Astrophysics Data System (ADS)

    Gurung, G.; Schwab, F. A.; Jo, B. G.; Lee, W. D.; Oh, C. W. W.

    2015-12-01

    It is sometimes not possible to find a single isotropic structure whose computed phase velocities fit both the experimental, fundamental-mode Love and Rayleigh wave data, for earth models that are perfectly elastic and are composed of thick, low contrast layers. Usually, velocity anisotropy of the body waves is applied to the earth models to fit the data. A few early studies used thin, high contrast layers in perfectly-elastic isotropic models to obtain approximate fit to the experimental data; here, we improve and expand this successful isotropic modelling by generalizing to realistic, anelastic layers, and by also requiring a fit to the fundamental-mode Love and Rayleigh wave amplitude-attenuation data. We treat the Love and Rayleigh wave data from the central United States, where this Love-Rayleigh "discrepancy" was discovered by McEvilly. Using only the experimental phase-velocity data, with the insertion of a thin, high contrast LVZ in each of the granitic, basaltic-grabbroic, and olivine regions, we find a continuum of isotropic models that give successful fits to the experimental data. Then by adding experimental amplitude-attenuation to the data, we attempt to reduce this huge volume of isotropic solutions: with the three thin LVZs, we successfully restricted the solutions by simultaneously fitting the experimental data for both Love and Rayleigh wave, phase-velocity and amplitude-attenuation dispersions. However, in the solution the body-wave velocities and Q values of these thin layers are improbably low, and these single-layer LVZs can only be considered effective representations; the true, physical situation requires the replacement of any one of these single-layer LVZs by a vertical distribution of N layers, each having the same thickness as the original thin layer. A simple scaling of the single-layer, seismic velocities and Qs then provides completely reasonable values for these parameters in the N-layer representation (which yields the same

  16. Determination of scattering coefficient considering wavelength and absorption dependence of anisotropy factor measured by polarized beam for biological tissues

    NASA Astrophysics Data System (ADS)

    Fukutomi, D.; Ishii, K.; Awazu, K.

    2015-12-01

    Anisotropy factor g, one of the optical properties of biological tissues, is the most important parameter to accurately determine scattering coefficient μs in the inverse Monte Carlo (iMC) simulation. It has been reported that g has wavelength and absorption dependence, however, there are few attempts in order to calculate μs of biological tissue considering the wavelength and absorption dependence of g. In this study, the scattering angular distributions of biological tissue phantoms were measured in order to determine g by using goniometric measurements with three polarization conditions at strongly and weakly absorbing wavelengths of hemoglobin. Then, optical properties, especially, μs were measured by integrating sphere measurements and iMC simulation in order to confirm the influence of measured g on optical properties in comparison of with general value of g (0.9) for soft biological tissue. Consequently, it was found that μs was overestimated at strongly absorbing wavelength, however, μs was underestimated at weakly absorbing wavelength if the g was not considered its wavelength and absorption dependence.

  17. Thick target measurement of the 40Ca(alpha,gamma)44Ti reaction rate

    SciTech Connect

    Sheets, S A; Burke, J T; Scielzo, N D; Phair, L; Bleuel, D; Norman, E B; Grant, P G; Hurst, A M; Tumey, S; Brown, T A; Stoyer, M

    2009-02-06

    The thick-target yield for the {sup 40}Ca({alpha},{gamma}){sup 44}Ti reaction has been measured for E{sub beam} = 4.13, 4.54, and 5.36 MeV using both an activation measurement and online {gamma}-ray spectroscopy. The results of the two measurements agree. From the measured yield a reaction rate is deduced that is smaller than statistical model calculations. This implies a smaller {sup 44}Ti production in supernova compared to recently measured {sup 40}Ca({alpha},{gamma}){sup 44}Ti reaction rates.

  18. Using gamma-ray emission to measure areal density of ICF capsules

    SciTech Connect

    Hoffman, Nelson M; Wilson, Douglas C; Hermann, Hans W; Young, Carlton S

    2010-01-01

    Fusion neutrons streaming from a burning ICF capsule generate gamma rays via nuclear inelastic scattering in the ablator of the capsule. The intensity of gamma-ray emission is proportional to the product of the ablator areal density ('{rho}R') and the yield of fusion neutrons, so by detecting the gamma rays we can infer the ablator areal density, provided we also have a measurement of the capsule's total neutron yield. In plastic-shell capsules, for example, {sup 12}C nuclei emit gamma rays at 4.44 MeV after excitation by 14.1-MeV neutrons from D+T fusion. These gamma rays can be measured by the Gamma Reaction History (GRH) experiment being built at the National Ignition Facility (NIF). A linear error analysis indicates the chief sources of uncertainty in inferred areal density.

  19. Estimates of rates and errors for measurements of direct-. gamma. and direct-. gamma. + jet production by polarized protons at RHIC

    SciTech Connect

    Beddo, M.E.; Spinka, H.; Underwood, D.G.

    1992-08-14

    Studies of inclusive direct-{gamma} production by pp interactions at RHIC energies were performed. Rates and the associated uncertainties on spin-spin observables for this process were computed for the planned PHENIX and STAR detectors at energies between {radical}s = 50 and 500 GeV. Also, rates were computed for direct-{gamma} + jet production for the STAR detector. The goal was to study the gluon spin distribution functions with such measurements. Recommendations concerning the electromagnetic calorimeter design and the need for an endcap calorimeter for STAR are made.

  20. U and Pu Gamma-Ray Measurements of Spent Fuel Using a Gamma-Ray Mirror Band-Pass Filter

    SciTech Connect

    Ziock, Klaus-Peter; Alameda, J.B.; Brejnholt, N.F.; Decker, T.A.; Descalle, M.A.; Fernandez-Perea, M.; Hill, R.M.; Kisner, R.A.; Melin, A.M.; Patton, B.W.; Ruz, J.; Soufli, R.; Pivovaroff, M.J.

    2014-01-01

    Abstract. We report on the use of grazing incidence gamma-ray mirrors to serve as a narrow band-pass filter for advanced non-destructive analysis (NDA) of spent nuclear fuel. The purpose of the mirrors is to limit the radiation reaching a HPGe detector to narrow spectral bands around characteristic emission lines from fissile isotopes in the fuel. This overcomes the normal rate issues when performing gamma-ray NDA measurements. In a proof-of-concept experiment, a set of simple flat gamma-ray mirrors were used to directly observe the atomic florescence lines from U and Pu from spent fuel pins with the detector located in a shirt-sleeve environment. The mirrors, consisting of highly polished silicon substrates deposited with WC/SiC multilayer coatings, successfully deflected the lines of interest while the intense primary radiation beam from the fuel was blocked by a lead beam stop. The gamma-ray multilayer coatings that make the mirrors work at the gamma-ray energies used here (~ 100 keV) have been experimentally tested at energies as high as 645 keV, indicating that direct observation of nuclear emission lines from 239Pu should be possible with an appropriately designed optic and shielding configuration.

  1. Crustal and mantle seismic anisotropy beneath the 'Great Lakes Mantle Divot' and adjacent areas: Constraints from shear-wave splitting measurements

    NASA Astrophysics Data System (ADS)

    Yang, B.; Gao, S. S.; Liu, K. H.; Dahm, H. H.; Kong, F.

    2015-12-01

    The recent availability of high-quality broadband seismic data from the deployment of the USArray Transportable Array stations from the Great Lakes to the eastern coast of North America provides a unique opportunity to investigate the origin of seismic anisotropy and to infer crustal/mantle structure and dynamics. Crustal anisotropy is quantified by using the sinusoidal moveout of the P-to-S converted phases from the Moho, and the integrated crustal/mantle anisotropy is measured using SKS, SKKS, and PKS (XKS) data recorded by 385 stations. A total of 3310 pairs of well-defined XKS splitting parameters are observed in the vicinity of the so-called Great Lakes Mantle Divot and adjacent areas. The measurements show systematic spatial variation of anisotropic characteristics. Fast polarization orientations subparallel to the absolute plate motion (APM) of North America are observed at most stations on and east of the Appalachians in the latitudinal range of 40° to 50°N with large splitting times (up to 1.7s). This area has a thin lithosphere relative to the continental interior to the west, indicating an asthenospheric origin for the observed azimuthally invariant splitting parameters which reflect a single-layer of anisotropy with a horizontal axis of symmetry. The dominant crustal anisotropy in this area is N-S oriented. Azimuthal varying splitting parameters are observed at most stations in the vicinity of the Great Lakes Mantle Divot, and can be adequately explained by a two-horizontal layer model. The lower layer has an APM-parallel fast orientation and the fast orientation of the upper layer is mostly consistent with the crust anisotropy. Based on the splitting measurements and previous seismic tomography studies, a model involving deflecting of asthenosphere flow by the undulating bottom of the lithosphere is proposed.

  2. Assessment of the neutron emission anisotropy factor of a sealed AmBe source by means of measurements and Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Loreti, S.; Pietropaolo, A.

    2015-10-01

    The neutron emission anisotropy factor of a sealed Americium-Beryllium source is experimentally determined and compared to Monte Carlo simulations. The measurements were done at the Italian Institute for Metrology of Ionizing Radiations using a long counter neutron detector and a "X.3" type AmBe sealed neutron source. Experimental data are compared to simulations performed with the MCNP code where the precise structure of the source is taken into account starting from its technical design. The contributions of the single structural parts are described to point out the effective sources of the emission anisotropy.

  3. Gamma ray bursts: A review of recent high-precision measurements

    NASA Technical Reports Server (NTRS)

    Cline, T. L.

    1981-01-01

    Recent measurements and discoveries in gamma ray bursts and transients are reviewed including observations of the red shifted annihilation line in two kinds of slow transients (in 'classical' gamma ray bursts and in the unique 1979 March 5th event); of red shifted nuclear lines in a slow transient and in one gamma ray burst; and of the positions of precise source locations of gamma ray bursts and of the March 5th event, within the supernova remnant N49 in the Large Magellanic Cloud.

  4. Gamma ray measurement of earth formation properties using a position sensitive scintillation detector

    SciTech Connect

    Sonne, D.S.

    1986-10-21

    This patent describes a system for measuring properties of earth formations in the vicinity of a well borehole at different radial distances from the borehole, comprising: a fluid tight hollow body member sized and adapted for passage through a well borehole and housing therein; a source of gamma rays and means for directing gamma rays from the source outwardly from the body member into earth formations in the vicinity of the borehole; and a position sensitive scintillation detector for detecting gamma rays scattered back into the body member from the earth formation in the vicinity of the borehole and means for collimating the scattered gamma rays onto the detector.

  5. Measurements of the anisotropy of the cosmic background radiation and diffuse galactic emission at millimeter and submillimeter wavelengths

    NASA Technical Reports Server (NTRS)

    Halpern, Mark; Benford, Richard; Meyer, Stephan; Muehlner, Dirk; Weiss, Rainer

    1988-01-01

    The results of a balloon-borne observing program to measure the large angular scale brightness distribution of the 2.7 K cosmic background radiation (CBR) at millimeter and submillimeter wavelengths are reported. A new determination of the dipole anisotropy of the CBR is found with 3.40 + or - 0.42 mK toward alpha = 12.1 + or - 0.24 hr, delta = - 23 + or - 5 deg in a 1.2 to 8/cm band and 4.7 + or - 1.4 mK toward alpha = 9.9 + 1.7 or - 1.1 hr, delta = - 38 + or - 21 deg between 5 and 18/cm, where the amplitudes are listed as thermodynamic temperatures. New estimates of the absolute temperature in these two bands of 2.86 + or - 0.26 K and 3.01 + or - 0.31 are obtained under the assumption that the CBR has a Planck spectrum. The diffuse Galactic emission is fitted by a secant distribution in Galactic latitude, and the resulting Galactic pole antenna temperatures are given. Maps of sky brightness, measurements of zodiacal emission, and measurements of fluctuations of the atmospheric emission which dominates the noise budget are also presented.

  6. Measurements of gamma-ray production cross sections for shielding materials of space nuclear systems

    NASA Technical Reports Server (NTRS)

    Orphan, V. J.; John, J.; Hoot, C. G.

    1972-01-01

    Measurements of secondary gamma ray production from neutron interactions have been made over the entire energy range of interest in shielding applications. The epithermal capture gamma ray yields for both resolved gamma ray lines and continuum have been measured from thermal energies to 100 KeV for natural tungsten and U-238, two important candidate shield materials in SNAP reactor systems. Data are presented to illustrate the variation of epithermal capture gamma ray yields with neutron energy. The gamma ray production cross sections from (n,xy) reactions have been measured for Fe and Al from the threshold energies for inelastic scattering to approximately 16 MeV. Typical Fe and Al cross sections obtained with high-neutron energy resolution and averaged over broad neutron-energy groups are presented.

  7. 10 CFR 35.635 - Full calibration measurements on gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Full calibration measurements on gamma stereotactic radiosurgery units. 35.635 Section 35.635 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.635 Full calibration...

  8. Measurement of Radon concentration by Xenon gamma-ray spectrometer for seismic monitoring of the Earth

    NASA Astrophysics Data System (ADS)

    Novikov, A.; Ulin, S.; Dmitrenko, V.; Vlasik, K.; Bychkova, O.; Petrenko, D.; Uteshev, Z.; Shustov, A.

    2016-02-01

    A method for earthquake precursors search based on variations of 222Rn concentration determined via intensity measurement of 222Rn daughter nuclei gamma ray emission lines by means of xenon gamma-ray spectrometer is discussed. The equipment description as well as the first experimental data are presented.

  9. Fermi large area telescope measurements of the diffuse gamma-ray emission at intermediate galactic latitudes.

    PubMed

    Abdo, A A; Ackermann, M; Ajello, M; Anderson, B; Atwood, W B; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Baughman, B M; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, T H; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cecchi, C; Charles, E; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Dereli, H; Dermer, C D; de Angelis, A; de Palma, F; Digel, S W; Di Bernardo, G; Dormody, M; do Couto e Silva, E; Drell, P S; Dubois, R; Dumora, D; Edmonds, Y; Farnier, C; Favuzzi, C; Fegan, S J; Focke, W B; Frailis, M; Fukazawa, Y; Funk, S; Fusco, P; Gaggero, D; Gargano, F; Gehrels, N; Germani, S; Giebels, B; Giglietto, N; Giordano, F; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M-H; Grove, J E; Guillemot, L; Guiriec, S; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Hughes, R E; Jóhannesson, G; Johnson, A S; Johnson, R P; Johnson, T J; Johnson, W N; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Kerr, M; Knödlseder, J; Kocian, M L; Kuehn, F; Kuss, M; Lande, J; Latronico, L; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Makeev, A; Mazziotta, M N; McConville, W; McEnery, J E; Meurer, C; Michelson, P F; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nolan, P L; Nuss, E; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, J F; Paneque, D; Panetta, J H; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Piron, F; Porter, T A; Rainò, S; Rando, R; Razzano, M; Reimer, A; Reimer, O; Reposeur, T; Ritz, S; Rodriguez, A Y; Roth, M; Ryde, F; Sadrozinski, H F-W; Sanchez, D; Sander, A; Saz Parkinson, P M; Scargle, J D; Sellerholm, A; Sgrò, C; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Starck, J-L; Stecker, F W; Striani, E; Strickman, M S; Strong, A W; Suson, D J; Tajima, H; Takahashi, H; Tanaka, T; Thayer, J B; Thayer, J G; Thompson, D J; Tibaldo, L; Torres, D F; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, T L; Vasileiou, V; Vilchez, N; Vitale, V; Waite, A P; Wang, P; Winer, B L; Wood, K S; Ylinen, T; Ziegler, M

    2009-12-18

    The diffuse galactic gamma-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray Observatory indicated excess gamma-ray emission greater, > or approximately equal to 1 GeV relative to diffuse galactic gamma-ray emission models consistent with directly measured CR spectra (the so-called "EGRET GeV excess"). The Large Area Telescope (LAT) instrument on the Fermi Gamma-Ray Space Telescope has measured the diffuse gamma-ray emission with improved sensitivity and resolution compared to EGRET. We report on LAT measurements for energies 100 MeV to 10 GeV and galactic latitudes 10 degrees < or = |b| < or = 20 degrees. The LAT spectrum for this region of the sky is well reproduced by a diffuse galactic gamma-ray emission model that is consistent with local CR spectra and inconsistent with the EGRET GeV excess. PMID:20366246

  10. Fermi Large Area Telescope Measurements of the Diffuse Gamma-Ray Emission at Intermediate Galactic Latitudes

    SciTech Connect

    Abdo, A.A.; Ackermann, M.; Ajello, M.; Anderson, B.; Atwood, W.B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Baughman, B.M.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R.D.; Bloom, E.D.; Bonamente, E.; Borgland, A.W.; Bregeon, J.; Brez, A.; Brigida, M.; /more authors..

    2012-04-11

    The diffuse galactic {gamma}-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray Observatory indicated excess {gamma}-ray emission {ge}1 GeV relative to diffuse galactic {gamma}-ray emission models consistent with directly measured CR spectra (the so-called 'EGRET GeV excess'). The Large Area Telescope (LAT) instrument on the Fermi Gamma-Ray Space Telescope has measured the diffuse {gamma}-ray emission with improved sensitivity and resolution compared to EGRET. We report on LAT measurements for energies 100 MeV to 10 GeV and galactic latitudes 10{sup o} {le} |b| {le} 20{sup o}. The LAT spectrum for this region of the sky is well reproduced by a diffuse galactic {gamma}-ray emission model that is consistent with local CR spectra and inconsistent with the EGRET GeV excess.

  11. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    NASA Astrophysics Data System (ADS)

    Jalali, Majid; Mohammadi, Ali

    2008-05-01

    The compounds Na 2B 4O 7, H 3BO 3, CdCl 2 and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the γ rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H 3BO 3 with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds.

  12. Centerband-only analysis of rotor-unsynchronized spin echo for measurement of lipid (31) P chemical shift anisotropy.

    PubMed

    Umegawa, Yuichi; Yamaguchi, Toshiyuki; Murata, Michio; Matsuoka, Shigeru

    2015-07-01

    Structural diversity and molecular flexibility of phospholipids are essential for biological membranes to play key roles in numerous cellular processes. Uncovering the behavior of individual lipids in membrane dynamics is crucial for understanding the molecular mechanisms underlying biological functions of cell membranes. In this paper, we introduce a simple method to investigate dynamics of lipid molecules in multi-component systems by measuring the (31) P chemical shift anisotropy (CSA) under magic angle spinning (MAS) conditions. For achieving both signal separation and CSA determination, we utilized a centerband-only analysis of rotor-unsynchronized spin echo (COARSE). This analysis is based on the curve fitting of periodic modulation of centerband intensity along the interpulse delay time in rotor-unsynchronized spin-echo experiments. The utility of COARSE was examined by using phospholipid vesicles, a three-component lipid raft model system, and archaeal purple membranes. We found that the apparent advantages of this method are high resolution and high sensitivity given by the moderate MAS speed and the one-dimensional acquisition with short spin-echo delays. COARSE provides an alternative method for CSA measurement that is effective in the investigation of lipid polymorphologies. PMID:26017552

  13. Shadowing and anisotropy of solar energetic ions at Mars measured by MAVEN during the March 2015 solar storm

    NASA Astrophysics Data System (ADS)

    Lillis, Robert J.; Lee, Christina O.; Larson, Davin; Luhmann, Janet G.; Halekas, Jasper S.; Connerney, Jack E. P.; Jakosky, Bruce M.

    2016-04-01

    The Solar Energetic Particle (SEP) Instrument on the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft is meant to characterize the variability of SEP fluxes at Mars. SEP ion precipitation is an important source of heating, ionization, and chemical changes in the upper atmosphere of Mars and may have played a substantial role in driving atmospheric escape over the history of the solar system. Here we examine SEP fluxes during a series of solar disturbances in late February through early March 2015. We present the first SEP ion pitch angle distributions measured at Mars and show how SEP anisotropy changes over the course of the event period. We present examples and explanations of several different kinds of variability in the SEP flux measured in the four fields of view of the instrument. Finally, we present a statistical study of energy- and angle-dependent shadowing of SEP under three different sets of heliospheric conditions, showing that the direct shadowing of SEP by the solid planet may be better explained in terms of simple geometry under quieter heliospheric conditions. In-depth understanding of the effects on SEP fluxes and precipitation patterns by the complex interplay between solar wind disturbances and Mars' magnetospheric configuration awaits detailed modeling studies.

  14. Airborne Spectral Measurements of Surface-Atmosphere Anisotropy for Arctic Sea Ice and Tundra

    NASA Technical Reports Server (NTRS)

    Arnold, G. Thomas; Tsay, Si-Chee; King, Michael D.; Li, Jason Y.; Soulen, Peter F.

    1999-01-01

    Angular distributions of spectral reflectance for four common arctic surfaces: snow-covered sea ice, melt-season sea ice, snow-covered tundra, and tundra shortly after snowmelt were measured using an aircraft based, high angular resolution (1-degree) multispectral radiometer. Results indicate bidirectional reflectance is higher for snow-covered sea ice than melt-season sea ice at all wavelengths between 0.47 and 2.3 pm, with the difference increasing with wavelength. Bidirectional reflectance of snow-covered tundra is higher than for snow-free tundra for measurements less than 1.64 pm, with the difference decreasing with wavelength. Bidirectional reflectance patterns of all measured surfaces show maximum reflectance in the forward scattering direction of the principal plane, with identifiable specular reflection for the melt-season sea ice and snow-free tundra cases. The snow-free tundra had the most significant backscatter, and the melt-season sea ice the least. For sea ice, bidirectional reflectance changes due to snowmelt were more significant than differences among the different types of melt-season sea ice. Also the spectral-hemispherical (plane) albedo of each measured arctic surface was computed. Comparing measured nadir reflectance to albedo for sea ice and snow-covered tundra shows albedo underestimated 5-40%, with the largest bias at wavelengths beyond 1 pm. For snow-free tundra, nadir reflectance underestimates plane albedo by about 30-50%.

  15. A measurement of secondary cosmic microwave background anisotropies from the 2500-square-degree SPT-SZ survey

    SciTech Connect

    George, E.M.; et al.

    2015-01-28

    We present measurements of secondary cosmic microwave background (CMB) anisotropies and cosmic infrared background (CIB) fluctuations using data from the South Pole Telescope (SPT) covering the complete 2540 deg(2) SPT-SZ survey area. Data in the three SPT-SZ frequency bands centered at 95, 150, and 220 GHz, are used to produce six angular power spectra (three single-frequency auto-spectra and three cross-spectra) covering the multipole range 2000 < ℓ < 11, 000 (angular scales 5' gsim θ gsim 1'). These are the most precise measurements of the angular power spectra at ℓ > 2500 at these frequencies. The main contributors to the power spectra at these angular scales and frequencies are the primary CMB, CIB, thermal and kinematic Sunyaev-Zel'dovich effects (tSZ and kSZ), and radio galaxies. We include a constraint on the tSZ power from a measurement of the tSZ bispectrum from 800 deg(2) of the SPT-SZ survey. We measure the tSZ power at 143  GHz to be $D^{\\rm tSZ}_{3000} = 4.08^{+0.58}_{-0.67}\\,\\mu {\\rm K}^2{}$ and the kSZ power to be $D^{\\rm kSZ}_{3000} = 2.9 \\pm 1.3\\, \\mu {\\rm K}^2{}$. The data prefer positive kSZ power at 98.1% CL. We measure a correlation coefficient of $\\xi = 0.113^{+0.057}_{-0.054}$ between sources of tSZ and CIB power, with ξ < 0 disfavored at a confidence level of 99.0%. The constraint on kSZ power can be interpreted as an upper limit on the duration of reionization. When the post-reionization homogeneous kSZ signal is accounted for, we find an upper limit on the duration Δz < 5.4  at 95% CL.

  16. A Measurement of Secondary Cosmic Microwave Background Anisotropies from the 2500 Square-degree SPT-SZ Survey

    NASA Astrophysics Data System (ADS)

    George, E. M.; Reichardt, C. L.; Aird, K. A.; Benson, B. A.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Cho, H.-M.; Crawford, T. M.; Crites, A. T.; de Haan, T.; Dobbs, M. A.; Dudley, J.; Halverson, N. W.; Harrington, N. L.; Holder, G. P.; Holzapfel, W. L.; Hou, Z.; Hrubes, J. D.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Lueker, M.; Luong-Van, D.; McMahon, J. J.; Mehl, J.; Meyer, S. S.; Millea, M.; Mocanu, L. M.; Mohr, J. J.; Montroy, T. E.; Padin, S.; Plagge, T.; Pryke, C.; Ruhl, J. E.; Schaffer, K. K.; Shaw, L.; Shirokoff, E.; Spieler, H. G.; Staniszewski, Z.; Stark, A. A.; Story, K. T.; van Engelen, A.; Vanderlinde, K.; Vieira, J. D.; Williamson, R.; Zahn, O.

    2015-02-01

    We present measurements of secondary cosmic microwave background (CMB) anisotropies and cosmic infrared background (CIB) fluctuations using data from the South Pole Telescope (SPT) covering the complete 2540 deg2 SPT-SZ survey area. Data in the three SPT-SZ frequency bands centered at 95, 150, and 220 GHz, are used to produce six angular power spectra (three single-frequency auto-spectra and three cross-spectra) covering the multipole range 2000 < l < 11, 000 (angular scales 5' >~ θ >~ 1'). These are the most precise measurements of the angular power spectra at l > 2500 at these frequencies. The main contributors to the power spectra at these angular scales and frequencies are the primary CMB, CIB, thermal and kinematic Sunyaev-Zel'dovich effects (tSZ and kSZ), and radio galaxies. We include a constraint on the tSZ power from a measurement of the tSZ bispectrum from 800 deg2 of the SPT-SZ survey. We measure the tSZ power at 143 GHz to be D^tSZ3000 = 4.08+0.58-0.67 μ K^2{} and the kSZ power to be D^kSZ3000 = 2.9 +/- 1.3 μ K^2{}. The data prefer positive kSZ power at 98.1% CL. We measure a correlation coefficient of ξ = 0.113+0.057-0.054 between sources of tSZ and CIB power, with ξ < 0 disfavored at a confidence level of 99.0%. The constraint on kSZ power can be interpreted as an upper limit on the duration of reionization. When the post-reionization homogeneous kSZ signal is accounted for, we find an upper limit on the duration Δz < 5.4 at 95% CL.

  17. Neutron and gamma dose and spectra measurements on the Little Boy replica

    SciTech Connect

    Hoots, S.; Wadsworth, D.

    1984-06-01

    The radiation-measurement team of the Weapons Engineering Division at Lawrence Livermore National Laboratory (LLNL) measured neutron and gamma dose and spectra on the Little Boy replica at Los Alamos National Laboratory (LANL) in April 1983. This assembly is a replica of the gun-type atomic bomb exploded over Hiroshima in 1945. These measurements support the National Academy of Sciences Program to reassess the radiation doses due to atomic bomb explosions in Japan. Specifically, the following types of information were important: neutron spectra as a function of geometry, gamma to neutron dose ratios out to 1.5 km, and neutron attenuation in the atmosphere. We measured neutron and gamma dose/fission from close-in to a kilometer out, and neutron and gamma spectra at 90 and 30/sup 0/ close-in. This paper describes these measurements and the results. 12 references, 13 figures, 5 tables.

  18. Fabry-Perot Laser Ultrasonic Elastic Anisotropy Measurements on a Moving Paper Web

    SciTech Connect

    Walter, John Bradley; Telschow, Kenneth Louis; Gerhardstein, J. P.; Pufahl, B. M.; Habeger, C. C; Lafond, E. M.; Brodeur, P. H.

    1999-07-01

    On-line measurement of material properties is a goal of many manufacturers to improve production and quality. The elastic stiffness of paper is important for the paper industry. Currently, the elastic constants of paper are measured offline with contact ultrasonic methods [1-4]. Piezoelectric transducers are placed in contact with the paper surface to generate and detect plate wave modes, known as Lamb wave modes [5-7]. At low frequencies, where the wavelength of the elastic wave is larger than the paper thickness, two wave modes dominate in the paper, an anti-symmetric or flexural mode and a symmetric or thickness mode. Measurements of the phase velocities of these modes along both the machine direction (MD) and the perpendicular cross direction (CD) of the paper web provide an important parameter revealing the increased stiffness in the paper along the MD direction.

  19. Measurement of the direct CP asymmetry in b-->s gamma Decays.

    PubMed

    Aubert, B; Barate, R; Boutigny, D; Couderc, F; Gaillard, J M; Hicheur, A; Karyotakis, Y; Lees, J P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; LeClerc, C; Lynch, G; Merchant, A M; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Ronan, M T; Shelkov, V G; Wenzel, W A; Ford, K; Harrison, T J; Hawkes, C M; Morgan, S E; Watson, A T; Fritsch, M; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Steinke, M; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; Wilson, F F; Cuhadar-Donszelmann, T; Hearty, C; Knecht, N S; Mattison, T S; McKenna, J A; Thiessen, D; Khan, A; Kyberd, P; Teodorescu, L; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Eschrich, I; Kirkby, D; Lankford, A J; Mandelkern, M; Mommsen, R K; Roethel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Gary, J W; Shen, B C; Wang, K; del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Levy, S L; Long, O; Lu, A; Mazur, M A; Richman, J D; Verkerke, W; Beck, T W; Eisner, A M; Heusch, C A; Lockman, W S; Schalk, T; Schmitz, R E; Schumm, B A; Seiden, A; Spradlin, P; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Blanc, F; Bloom, P; Chen, S; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Smith, J G; Zhang, J; Zhang, L; Chen, A; Harton, J L; Soffer, A; Toki, W H; Wilson, R J; Zeng, Q L; Altenburg, D; Brandt, T; Brose, J; Colberg, T; Dickopp, M; Feltresi, E; Hauke, A; Lacker, H M; Maly, E; Müller-Pfefferkorn, R; Nogowski, R; Otto, S; Petzold, A; Schubert, J; Schubert, K R; Schwierz, R; Spaan, B; Sundermann, J E; Bernard, D; Bonneaud, G R; Brochard, F; Grenier, P; Schrenk, S; Thiebaux, C; Vasileiadis, G; Verderi, M; Bard, D J; Clark, P J; Lavin, D; Muheim, F; Playfer, S; Xie, Y; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Baldini-Ferroli, R; Calcaterra, A; de Sangro, R; Finocchiaro, G; Patteri, P; Piccolo, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Brandenburg, G; Morii, M; Won, E; Dubitzky, R S; Langenegger, U; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Gaillard, J R; Morton, G W; Nash, J A; Taylor, G P; Grenier, G J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Yi, J; Davier, M; Grosdidier, G; Höcker, A; Laplace, S; Le Diberder, F; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Coleman, J P; Fry, J R; Gabathuler, E; Gamet, R; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Cormack, C M; Harrison, P F; Mohanty, G B; Brown, C L; Cowan, G; Flack, R L; Flaecher, H U; Green, M G; Marker, C E; McMahon, T R; Ricciardi, S; Salvatore, F; Vaitsas, G; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hart, P A; Hodgkinson, M C; Lafferty, G D; Lyon, A J; Williams, J C; Farbin, A; Hulsbergen, W D; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Flood, K T; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Staengle, H; Willocq, S; Cowan, R; Sciolla, G; Taylor, F; Yamamoto, R K; Mangeol, D J J; Patel, P M; Robertson, S H; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Taras, P; Nicholson, H; Cavallo, N; Fabozzi, F; Gatto, C; Lista, L; Monorchio, D; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M; Bulten, H; Raven, G; Wilden, L; Jessop, C P; LoSecco, J M; Gabriel, T A; Allmendinger, T; Brau, B; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Rahimi, A M; Ter-Antonyan, R; Wong, Q K; Brau, J; Frey, R; Igonkina, O; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Tiozzo, G; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; de la Vaissière, C; Del Buono, L; Hamon, O; John, M J J; Leruste, P; Ocariz, J; Pivk, M; Roos, L; T'Jampens, S; Therin, G; Manfredi, P F; Re, V; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Anulli, F; Biasini, M; Peruzzi, I M; Pioppi, M; Angelini, C; Batignani, G; Bettarini, S; Bondioli, M; Bucci, F; Calderini, G; Carpinelli, M; Del Gamba, V; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Martinez-Vidal, F; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Sandrelli, F; Walsh, J; Haire, M; Judd, D; Paick, K; Wagoner, D E; Danielson, N; Elmer, P; Lau, Y P; Lu, C; Miftakov, V; Olsen, J; Smith, A J S; Telnov, A V; Bellini, F; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Li Gioi, L; Mazzoni, M A; Morganti, S; Pierini, M; Piredda, G; Safai Tehrani, F; Voena, C; Christ, S; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B; Geddes, N I; Gopal, G P; Olaiya, E O; Aleksan, R; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P F; Hamel de Monchenault, G; Kozanecki, W; Langer, M; Legendre, M; London, G W; Mayer, B; Schott, G; Vasseur, G; Yèche, C; Zito, M; Purohit, M V; Weidemann, A W; Yumiceva, F X; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmueller, O L; Convery, M R; Cristinziani, M; De Nardo, G; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W; Elsen, E E; Fan, S; Field, R C; Glanzman, T; Gowdy, S J; Hadig, T; Halyo, V; Hast, C; Hryn'ova, T; Innes, W R; Kelsey, M H; Kim, P; Kocian, M L; Leith, D W G S; Libby, J; Luitz, S; Luth, V; Lynch, H L; Marsiske, H; Messner, R; Muller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Petrak, S; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Simi, G; Snyder, A; Soha, A; Stelzer, J; Su, D; Sullivan, M K; Va'vra, J; Wagner, S R; Weaver, M; Weinstein, A J R; Wisniewski, W J; Wittgen, M; Wright, D H; Yarritu, A K; Young, C C; Burchat, P R; Edwards, A J; Meyer, T I; Petersen, B A; Roat, C; Ahmed, S; Alam, M S; Ernst, J A; Saeed, M A; Saleem, M; Wappler, F R; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Kim, H; Ritchie, J L; Satpathy, A; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bona, M; Gallo, F; Gamba, D; Borean, C; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Poropat, P; Vitale, L; Vuagnin, G; Panvini, R S; Banerjee, S; Brown, C M; Fortin, D; Jackson, P D; Kowalewski, R; Roney, J M; Band, H R; Dasu, S; Datta, M; Eichenbaum, A M; Graham, M; Hollar, J J; Johnson, J R; Kutter, P E; Li, H; Liu, R; Di Lodovico, F; Mihalyi, A; Mohapatra, A K; Pan, Y; Prepost, R; Rubin, A E; Sekula, S J; Tan, P; von Wimmersperg-Toeller, J H; Wu, J; Wu, S L; Yu, Z; Neal, H

    2004-07-01

    We describe a measurement of the direct CP asymmetry between inclusive b-->s gamma and b-->s gamma decays. This asymmetry is expected to be less than 0.01 in the standard model, but could be enhanced up to about 0.10 by new physics contributions. We use a sample of 89 x 10(6) BB pairs recorded with the BABAR detector at SLAC PEP-II, from which we reconstruct a set of 12 exclusive b-->s gamma final states containing one charged or neutral kaon and one to three pions. We measure an asymmetry of A(CP)(b-->s gamma)=0.025+/-0.050(stat)+/-0.015(syst), corresponding to an allowed range of -0.06s gamma)<+0.11 at 90% confidence level. PMID:15323901

  20. First Direct Measurement of the 17F(p,gamma)18Ne Cross Section

    SciTech Connect

    Chipps, K.; Bardayan, Daniel W; Nesaraja, Caroline D; Pain, S. D.; Smith, Michael Scott; Blackmon, Jeff C; Chae, K. Y.; Moazen, Brian; Pittman, S. T.; Greife, U.; Hatarik, Robert; Peters, W. A.; Kozub, R. L.; ShrinerJr., J. F.; Matei, Catalin

    2009-01-01

    The rate of the {sup 17}F(p,{gamma}){sup 18}Ne reaction is important in various astrophysical events. A previous {sup 17}F(p,p){sup 17}F measurement identified a 3{sup +} state providing the strongest resonance contribution, but the resonance strength was unknown. We have directly measured the {sup 17}F(p,{gamma}){sup 18}Ne reaction using a mixed beam of {sup 17}F and {sup 17}O at ORNL. The resonance strength for the 3{sup +} resonance in {sup 18}Ne was found to be {omega}{gamma} = 33 {+-} 14(stat) {+-} 17(syst) meV, corresponding to a {gamma} width of {Lambda}{sub {gamma}} = 56 {+-} 24(stat) {+-} 30(syst) meV. An upper limit on the direct capture of S(E) {le} 65 keV b was determined at an energy of 800 keV.

  1. Z + {gamma} cross-section measurement, {sigma}*BR(Z + {gamma}), in the electron channel for p{bar p} collisions at {radical}s = 1.8 TeV, and limits for the ZZ{gamma} and Z{gamma}{gamma} anomalous couplings

    SciTech Connect

    Roach-Bellino, M.

    1994-02-01

    The Z + {gamma} cross-section x branching ratio in the electron channel has been measured using the inclusive Z data sample from the CDF 1988--1989 collider run, for which the total integrated luminosity was 4.05 {plus_minus} 0.28 pb{sup {minus}1}. Two Z{gamma} candidates are observed from central photon events with {Delta}R/{sub {gamma}} > 0.7 and E{sub t}{sup {gamma}} > 5.0 GeV. From these events the {sigma} * BR(Z + {gamma}) is measured and compared with SM predictions: {sigma} * BR(Z + {gamma}){sub e} = 6.8{sub {minus}5.7}{sup +5.7}(stat + syst)pb {sigma} * BR(Z + {gamma})SM = 4.7{sub {minus}4.7}{sup +0.7}(stat + syst)pb. From this ZZ{sub {gamma}} cross section measurement limits on the Z{sub {gamma}{gamma}} and couplings for three different choices of compositeness scale {Lambda}{sub Z} are obtained. The experimental sensitivity to the h{sub 30}{sup Z,{gamma}}/h{sub 10}{sup Z,{gamma}} couplings is in the range of {Lambda}{sub Z} {approximately} 450--500 GeV and for the h{sub 40}{sup Z{gamma}}/h{sub 20}{sup Z,{gamma}} couplings {Lambda}{sub Z} {approximately} 300 GeV.

  2. First-Light Galaxies or Intrahalo Stars: Multi-Wavelength Measurements of the Infrared Background Anisotropies

    NASA Astrophysics Data System (ADS)

    Cooray, Asantha

    The research program described in this proposal can be broadly described as data analysis, measurement, and interpretation of the spatial fluctuations of the unresolved cosmic IR background. We will focus primarily on the background at optical and near-IR wavelengths as probed by Hubble and Spitzer. As absolute background intensity measurements are challenging, the focus is on the spatial fluctuations similar to the anisotropiesof the cosmic microwave background (CMB). Measurements of the unresolved Spitzer fluctuations by two independent teams on multiple fields agree within the measurement errors. However, there are now two interpretations on the origin of the unresolved IRAC fluctuations. One involves a population of faint sources at very high redshifts (z > 6) during the epoch of reionization. The second interpretation involves the integrated emission from intrahalo light associated with diffuse stars in the outskirts of z of 1 to 3 dark matter halos of galaxies. We now propose to further test these two interpretations with a new set of measurements at shorter IR and optical wavelengths with HST/ACS and WFC3 overlapping with deep IRAC surveys. A multi-wavelength study from 0.5 to 4.5 micron will allow us to independently determine the relative contribution of intrahalo light and z > 8 faint galaxies to the unresolved IR fluctuations. We will also place strong limits on the surface density of faint sources at z > 8. Such a limit will be useful for planning deep surveys with JWST. Moving to the recent wide IRAC fields with the warm mission, we propose to study fluctuations at tens of degree angular scales. At such large angular scales IRAC fluctuations should trace diffuse Galactic light (DGL), ISM dust-scattered starlight in our Galaxy. We will measure the amplitude and slope of the DGL power spectrum and compare them to measurements of the Galactic dust power spectrum from IRAS and Planck and study if the large degree-scale fluctuations seen in CIBER can be

  3. IR ellipsometry for surface anisotropy measurement: applications to pulp and paper industry

    NASA Astrophysics Data System (ADS)

    Bernard, Pierre; Charlebois, Alain

    1998-09-01

    Uniformity of physical properties of paper continues to be one of the most serious quality issues in today's paper mills. The large-scale `average' profile can often be controlled effectively with today's technologies. However, to detect and control sizes from several microns to a few centimeters remains the industry's biggest challenge. Over the last several years, INO has developed and perfected an entirely new instrument to measure surface fiber orientation. This non-destructive, non-contact technique can more appropriately be described as a surface strain tester. It is slowly finding its way in various laboratories around the world, notably Sweden, United States and France. The instrument uses a custom designed phase-modulated, laser- based ellipsometer in the far infrared spectral region. It basically measures the local surface birefringence and direction of the optic axis. Our approach is highly unusual since it works for samples of widely varying surface roughness and does not require careful alignment of the sample with respect to the laser beam. This paper describes how the instrument works, what it measures and illustrates various applications from small scale mapping to cross- machine profiles.

  4. Effects of graphite porosity and anisotropy on measurements of elastic modulus using laser untrasonics

    SciTech Connect

    Spicer, James B; Zeng, Fan W; Han, Karen; Olasov, Lauren R; Gallego, Nidia C; Contescu, Cristian I

    2014-01-01

    Laser ultrasonic techniques can be used to study the ultrasonic properties of nuclear graphites and can serve as tools in establishing relationships between materials microstructure and the macroscopic stiffnesses of graphite. Establishing structure-property relationships permits improved ultrasonic sensing of graphite microstructural changes related to service-induced degradation. Laser ultrasonic measurements were made using a pulsed Nd:YAG laser source and detection was performed using a Michelson-type interferometer. This source-receiver combination provides for non-contacting, highly linear transduction of broadbanded, ultrasonic pulses permitting simultaneous determination of longitudinal and shear stiffnesses. Measurements show that among the graphites examined, a change in density of 0.26 g/cm3 (average 1.8 g/cm3) results in a change in the longitudinal elastic stiffness of 9.2 GPa (average 11.3 GPa) and 3.2 GPa (average 4.3 GPa) for the shear stiffness. Larger variations in density were produced by controlled oxidation of IG-110 and NBG-18. Shear wave birefringence measurements using laser line sources in IG-110 and PCEA indicate that IG-110 behaves isotropically while PCEA displays texture characteristic of transversely isotropic materials.

  5. The jackknife as an approach for uncertainty assessment in gamma spectrometric measurements of uranium isotope ratios

    NASA Astrophysics Data System (ADS)

    Ramebäck, H.; Vesterlund, A.; Tovedal, A.; Nygren, U.; Wallberg, L.; Holm, E.; Ekberg, C.; Skarnemark, G.

    2010-08-01

    The jackknife as an approach for uncertainty estimation in gamma spectrometric uranium isotope ratio measurements was evaluated. Five different materials ranging from depleted uranium (DU) to high enriched uranium (HEU) were measured using gamma spectrometry. High resolution inductively coupled plasma mass spectrometry (ICP-SFMS) was used as a reference method for comparing the results obtained with the gamma spectrometric method. The relative combined uncertainty in the gamma spectrometric measurements of the 238U/ 235U isotope ratio using the jackknife was about 10-20% ( k = 2), which proved to be fit-for-purpose in order to distinguish between different uranium categories. Moreover, the enrichment of 235U in HEU could be measured with an uncertainty of 1-2%.

  6. The second measurement of anisotropy in the cosmic microwavebackground radiation at 0.degrees 5 scales near the star mu Pegasi

    SciTech Connect

    Lim, M.A.; Clapp, A.C.; Devlin, M.J.; Figueiredo, N.; Gundersen,J.O.; Hanany, S.; Hristov, V.V.; Lange, A.E.; Lubin, P.M.; Meinhold,P.R.; Richards, P.L.; Staren, J.W.; Smoot, G.F.; Tanaka, S.T.

    1996-05-22

    During the fifth flight of the Microwave Anisotropy Experiment (MAX5), we revisited a region with significant dust emission near the star mu Pegasi. A 3.5 cm(-1) low-frequency channel has been added since the previous measurement (Meinhold et al. 1993a). The data in each channel clearly show structure correlated with IRAS 100 mu m dust emission. The spectrum of the structure in the 6, 9, and 14 cm(-1)channels is described by I-v proportional to nu(beta)B(nu) (T-dust),where beta = 1.3 and T-dust = 19 K and B-v is the Planck function. However, this model predicts a smaller amplitude in the 3.5 cm(-1) band than is observed. Considering only linear combinations of the data independent of the best-fit foreground spectrum for the three lower channels, we find an upper limit to CMBR fluctuations of Delta T/T =(C(l)l(l + 1)/2 pi)(1/2) less than or equal to 1.3 x 10(-5) at the 95 percent confidence level. The result is for a flat-band power spectrum and does not include a 10 percent uncertainty in calibration. It is consistent with our previous observation in the region.

  7. ICF burn-history measurments using 17-MeV fusion gamma rays

    SciTech Connect

    Lerche, R.A.; Cable, M.D.; Dendooven, P.G.

    1995-04-12

    Fusion reaction rate for inertial-confinement fusion (ICF) experiments at the Nova Laser Facility is measured with 30-ps resolution using a high-speed neutron detector. We are investigating a measurement technique based on the 16.7-MeV gamma rays that are released in deuterium-tritium fusion. Our concept is to convert gamma-ray energy into a fast burst of Cerenkov light that can be recorded with a high-speed optical detector. We have detected fusion gamma rays in preliminary experiments conducted at Nova where we used a tungsten/aerogel converter to generate Cerenkov light and an optical streak camera to record the signal.

  8. Method and apparatus for measuring micro structures, anisotropy and birefringence in polymers using laser scattered light

    DOEpatents

    Grek, Boris; Bartolick, Joseph; Kennedy, Alan D.

    2000-01-01

    A method and apparatus for measuring microstructures, anistropy and birefringence in polymers using laser scattered light includes a laser which provides a beam that can be conditioned and is directed at a fiber or film which causes the beam to scatter. Backscatter light is received and processed with detectors and beam splitters to obtain data. The data is directed to a computer where it is processed to obtain information about the fiber or film, such as the birefringence and diameter. This information provides a basis for modifications to the production process to enhance the process.

  9. Studies of charmed hadronic B decays with the early LHCb data and prospects for {gamma} measurements

    SciTech Connect

    Nardulli, J.

    2010-12-22

    We present the first studies of decays of the type B{yields}DX, where D represents a charmed meson (D{sup 0}, D{sup (*)+}, or D{sub s}) from the LHCb experiment at CERN. Our studies use data accumulated during the 2010 run of the LHC. This work represents the first steps on a programme towards a precision measurement of the angle {gamma} of the CKM Unitarity Triangle. The prospects for this {gamma} measurement will be reviewed.

  10. Quantitative Characterization Of The Interactions Of Some Glycolytic Enzymes: An Application Of The Fluorescence Anisotropy Measurement

    NASA Astrophysics Data System (ADS)

    Tompa, Peter; Bar, Jorg; Batke, Jozsef

    1988-06-01

    The affinity of Saccharomyces cerevisiae fructose-1,6-bisphosphate aldolase towards the metabolically related enzymes phosphofructokinase (PFK), triosephosphate isomerase (TPI) and glyceraldehyde-3-phosphate dehydrogenase (GPDH) was tested by using the signal of fluorescein isothiocyanate (FITC) attached covalently to the aldolase. The dissociation constants of the enzyme-enzyme complexes and rate constants of their formation and dissociation were measured and compared with the same parameters derived for enzymes from rabbit muscle. Hybrid complex formation between yeast aldolase and muscle GPDH and between muscle aldolase and yeast GPDH have also been observed. From the similarities in the determined parameters for the yeast and muscle enzymes we concluded that organization based on direct enzyme-enzyme interactions may be an ancient characteristic of the cytoplasm. The existence of in vitro hybrid complexes indicates that the recognition sites responsible for these interactions may have been conserved during the evolution.