WorldWideScience

Sample records for magnetic diffraction experiments

  1. A cooled avalanche photodiode detector for X-ray magnetic diffraction experiments

    CERN Document Server

    Kishimoto, S; Ito, M

    2001-01-01

    A cooled avalanche photodiode (APD) detector was developed for X-ray magnetic diffraction experiments. A stack of four silicon APDs was cooled down to 243 K by a thermoelectric cooler. The energy widths of 0.89 and 1.55 keV (FWHM) were obtained for 8.05 keV X-rays at 1x10 sup 6 s sup - sup 1 and for 16.53 keV X-rays at 2x10 sup 6 s sup - sup 1 , respectively. Test measurements of X-ray magnetic diffraction were executed using a terbium single crystal and white synchrotron radiation. A peak width of (1 0 3) reflection (5.4 keV) was roughly three times wider than that with a high-purity germanium detector.

  2. A study of magnetic moments of CeRh3B2 by X-ray magnetic diffraction experiments

    Science.gov (United States)

    Ito, M.; Suzuki, K.; Tadenuma, T.; Nagayasu, R.; Sakurai, Y.; Onuki, Y.; Nishibori, E.; Sakata, M.

    2014-04-01

    X-ray magnetic diffraction experiments of a ferromagnetic rare-earth compound CeRh3B2 have been performed, and the spin and orbital magnetic form factors have been measured. Density distributions of the spin and orbital magnetic moments in real space have been obtained by using Maximum Entropy Method. Low peaks at Rh sites as well as high peaks at Ce sites are observed in these distribution maps. We have estimated the spin and orbital magnetic moments at the Ce and Rh sites in the distribution maps, and have obtained small but nonnegligible spin and orbital magnetic moments of Rh. This is probably the first experimental evidence showing existence of the spin and orbital moments of Rh in this compound.

  3. Multidataset Refinement Resonant Diffraction, and Magnetic Structures.

    Science.gov (United States)

    Attfield, J Paul

    2004-01-01

    The scope of Rietveld and other powder diffraction refinements continues to expand, driven by improvements in instrumentation, methodology and software. This will be illustrated by examples from our research in recent years. Multidataset refinement is now commonplace; the datasets may be from different detectors, e.g., in a time-of-flight experiment, or from separate experiments, such as at several x-ray energies giving resonant information. The complementary use of x rays and neutrons is exemplified by a recent combined refinement of the monoclinic superstructure of magnetite, Fe3O4, below the 122 K Verwey transition, which reveals evidence for Fe(2+)/Fe(3+) charge ordering. Powder neutron diffraction data continue to be used for the solution and Rietveld refinement of magnetic structures. Time-of-flight instruments on cold neutron sources can produce data that have a high intensity and good resolution at high d-spacings. Such profiles have been used to study incommensurate magnetic structures such as FeAsO4 and β-CrPO4. A multiphase, multidataset refinement of the phase-separated perovskite (Pr0.35Y0.07Th0.04Ca0.04Sr0.5)MnO3 has been used to fit three components with different crystal and magnetic structures at low temperatures.

  4. Bragg diffraction from magnetic materials

    DEFF Research Database (Denmark)

    Lebech, B.

    2002-01-01

    Neutrons form a penetrating neutral probe, which makes it possible to use neutrons scattering techniques to study bulk materials, localise both light and heavy atoms and to distinguish between isotopes (e.g. hydrogen and deuterium). These properties make neutron scattering complementary to X-ray......, polarised neutron scattering (polarisation analysis) and magnetic X-ray scattering) and their relevance for the particular study will be elucidated. (C) 2002 Elsevier Science B.V. All rights reserved....... scattering when studying crystalline properties of matter. In addition, neutrons possess magnetic moments of the same order of magnitude as the atomic magnetic moments in elements and this makes neutrons highly suited for studies of the order and interactions between the magnetic moments in magnetic...

  5. Undergraduate Experiment with Fractal Diffraction Gratings

    Science.gov (United States)

    Monsoriu, Juan A.; Furlan, Walter D.; Pons, Amparo; Barreiro, Juan C.; Gimenez, Marcos H.

    2011-01-01

    We present a simple diffraction experiment with fractal gratings based on the triadic Cantor set. Diffraction by fractals is proposed as a motivating strategy for students of optics in the potential applications of optical processing. Fraunhofer diffraction patterns are obtained using standard equipment present in most undergraduate physics…

  6. X-ray magnetic diffraction of ferromagnets with synchrotron radiation

    CERN Document Server

    Ito, M

    2002-01-01

    X-ray magnetic diffraction experiment of ferromagnets that utilizes elliptically polarized synchrotron radiation is presented. First we have reviewed shortly historical backgrounds and theoretical aspects of the experiment. We have presented how the magnetic form factors are measured and are separated into the spin-moment component and the orbital-moment component in this experiment. Peculiar features of the polarization factor of this experiment have been explained. We have introduced two examples of the experiment. One is the measurement of the spin-magnetic form factor of SmAl sub 2 with white X-rays from a bending magnet at the Photon Factory. The other is the measurement of the orbital-magnetic form factor of Holmium Iron Garnets with monochromatic X-rays from an undulator at the SPring-8. Finally we summarize the article and show some future prospects of this experiment. (author)

  7. Multidataset Refinement Resonant Diffraction, and Magnetic Structures

    OpenAIRE

    Attfield, J. Paul

    2004-01-01

    The scope of Rietveld and other powder diffraction refinements continues to expand, driven by improvements in instrumentation, methodology and software. This will be illustrated by examples from our research in recent years. Multidataset refinement is now commonplace; the datasets may be from different detectors, e.g., in a time-of-flight experiment, or from separate experiments, such as at several x-ray energies giving resonant information. The complementary use of x rays and neutrons is exe...

  8. Effect of recording condition on the diffraction efficiency of magnetic hologram with magnetic garnet films

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Yuichi, E-mail: nakamura@ee.tut.ac.jp; Takagi, Hiroyuki; Lim, Pang Boey; Inoue, Mitsuteru [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, 1-1 Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

    2014-09-14

    A holographic memory has been attracting attention as recording media with high recording density and high data transfer rate. We have studied the magnetic garnets as a rewritable and long life media for magnetic holography. However, since the signal intensity of reconstructed image was relatively low, the effects of recording conditions on the diffraction efficiency of magnetic hologram were investigated with experiments and the numerical simulation using COMSOL multi-physics. The diffraction efficiency tends to decrease as increasing the spatial frequency, and the use of short pulse laser with the pulse width of 50 ps was found to be effective to achieve high diffraction efficiency. This suggests that the formation of clear magnetic fringe similar to interference pattern can be obtained by the use of short pulse laser since undesirable heat diffusion during radiation does not occur. On the other hand, the diffraction efficiency increased as increasing the film thickness up to 3.1 μm but was saturated in the garnet film thicker than 3.1 μm in the case of spatial frequency of 1500 line pair/mm. The numerical simulation showed that the effective depth of magnetic fringe was limited about 1.8 μm irrespective of the garnet film thickness because the fringes were connected by thermal diffusion near the surface of the film, and the effective depth is limited due to this connection of the magnetic fringe. Avoiding this fringe connection, much higher diffraction efficiency will be achieved.

  9. Magnetic correlations in oxides: Neutron diffraction and neutron depolarization study

    Indian Academy of Sciences (India)

    S M Yusuf

    2008-10-01

    We have studied magnetic correlations in several oxide materials that belong to colossal magnetoresistive, naturally occurring layered oxide showing low-dimensional magnetic ordering, solid oxide fuel cell interconnect materials, and magnetic nanoparticles using neutron diffraction and neutron depolarization techniques. In this paper, an overview of some of these results is given.

  10. Diffraction patterns in ferrofluids: Effect of magnetic field and gravity

    Energy Technology Data Exchange (ETDEWEB)

    Radha, S., E-mail: radhasri12@gmail.com [Department of Physics, University of Mumbai, Mumbai 400098 (India); Mohan, Shalini [Department of Physics, University of Mumbai, Mumbai 400098 (India); UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Mumbai 400098 (India); Pai, Chintamani [Department of Physics, University of Mumbai, Mumbai 400098 (India)

    2014-09-01

    In this paper, we report the experimental observation of diffraction patterns in a ferrofluid comprising of Fe{sub 3}O{sub 4} nanoparticles in hexane by a 10 mW He–Ne laser beam. An external dc magnetic field (0–2 kG) was applied perpendicular to the beam. The diffraction pattern showed a variation at different depths of the sample in both zero and applied magnetic field. The patterns also exhibit a change in shape and size as the external field is varied. This effect arises due to thermally induced self-diffraction under the influence of gravity and external magnetic field.

  11. Magnetization and neutron diffraction studies on FeCrP

    Indian Academy of Sciences (India)

    Sudhish Kumar; Anjali Krishnamurthy; Bipin K Srivastava; A Das; S K Paranjpe

    2004-08-01

    Crystal structure and magnetic behaviour of FeCrP have been investigated using magnetization and neutron diffraction measurements. FeCrP crystallizes in orthorhombic FeZrP type structure (nma space group, = 4) in which Cr atoms occupy the pyramidal site and Fe atoms occupy the tetrahedral site with total preference. Structural parameters including positional parameters have been refined. The refined values of positional parameters for Fe and Cr are quite different from those in FeZrP. The nature of magnetization{temperature curve is suggestive of antiferromagnetic nature with N = 280 (± 10) K. Preliminary analysis of neutron diffraction pattern at 13 K is indicative of a rather complicated magnetic structure.

  12. Neutron Diffraction Studies of Nuclear Magnetic Ordering in Copper

    DEFF Research Database (Denmark)

    Jyrkkiö, T.A.; Huiku, M.T.; Siemensmeyer, K.;

    1989-01-01

    to depend strongly on the external magnetic field between zero and the critical fieldB c=0.25 mT, indicating the existence of at least two antiferromagnetic phases. The results are compared to previous measurements of the magnetic susceptibility. Theoretical calculations do not provide a full explanation......We have constructed a two-stage nuclear demagnetization cryostat for neutron diffraction studies of nuclear magnetism in copper. The cryostat is combined with a two-axis neutron spectrometer which can use both polarized and unpolarized neutrons. By demagnetizing highly polarized copper nuclear...

  13. Sample cell for in-field X-ray diffraction experiments

    Directory of Open Access Journals (Sweden)

    Viktor Höglin

    2015-01-01

    Full Text Available A sample cell making it possible to perform synchrotron radiation X-ray powder diffraction experiments in a magnetic field of 0.35 T has been constructed. The device is an add-on to an existing sample cell and contains a strong permanent magnet of NdFeB-type. Experiments have shown that the setup is working satisfactory making it possible to perform in-field measurements.

  14. Measuring slit width and separation in a diffraction experiment

    Energy Technology Data Exchange (ETDEWEB)

    Gan, K K; Law, A T [Department of Physics, Ohio State University, Columbus, OH 43210 (United States)], E-mail: gan@mps.ohio-state.edu

    2009-11-15

    We present a procedure for measuring slit width and separation in single- and double-slit diffraction experiments. Intensity spectra of diffracted laser light are measured with an optical sensor (PIN diode). Slit widths and separations are extracted by fitting to the measured spectra. We present a simple fitting procedure to account for the integration (averaging) of light across the finite sensor aperture. This experiment provides students with a quantitative, in-depth verification of diffraction theory, as well as hands-on experience in sophisticated fitting methods.

  15. The Heisenberg Uncertainty Principle Demonstrated with An Electron Diffraction Experiment

    Science.gov (United States)

    Matteucci, Giorgio; Ferrari, Loris; Migliori, Andrea

    2010-01-01

    An experiment analogous to the classical diffraction of light from a circular aperture has been realized with electrons. The results are used to introduce undergraduate students to the wave behaviour of electrons. The diffraction fringes produced by the circular aperture are compared to those predicted by quantum mechanics and are exploited to…

  16. Reconstructing an icosahedral virus from single-particle diffraction experiments.

    Science.gov (United States)

    Saldin, D K; Poon, H-C; Schwander, P; Uddin, M; Schmidt, M

    2011-08-29

    The first experimental data from single-particle scattering experiments from free electron lasers (FELs) are now becoming available. The first such experiments are being performed on relatively large objects such as viruses, which produce relatively low-resolution, low-noise diffraction patterns in so-called "diffract-and-destroy" experiments. We describe a very simple test on the angular correlations of measured diffraction data to determine if the scattering is from an icosahedral particle. If this is confirmed, the efficient algorithm proposed can then combine diffraction data from multiple shots of particles in random unknown orientations to generate a full 3D image of the icosahedral particle. We demonstrate this with a simulation for the satellite tobacco necrosis virus (STNV), the atomic coordinates of whose asymmetric unit is given in Protein Data Bank entry 2BUK.

  17. High energy diffraction processes - TOTEM experiment

    CERN Document Server

    Kaspar, Jan

    2005-01-01

    We study two problems in this thesis. First, we analyse a model for pp and anti-pp elastic scattering. The model was developed by M.M.Islam and coworkers in the past 25 years. Our aim was to make a prediction for differential cross section of pp scattering at energy of 14 TeV which will be measured by the TOTEM experiment at the LHC at CERN. Since protons carry electromagnetic charge, we had to take into account an electromagnetic interaction and effects of the interference between electromagnetic and hadronic forces. We also analysed the model in the impact parameter representation. It enabled us to gain information about range of hadronic forces responsible for elastic, inelastic and total pp and anti-pp scattering. In the second part we present our alignment method for detectors inside the Roman pots of the TOTEM experiment. The method was used during Roman Pot tests on the SPS beam last year.

  18. Diffraction grating characterisation for cold-atom experiments

    CERN Document Server

    McGilligan, James P; Riis, Erling; Arnold, Aidan S

    2016-01-01

    We have studied the optical properties of gratings micro-fabricated into semiconductor wafers, which can be used for simplifying cold-atom experiments. The study entailed characterisation of diffraction efficiency as a function of coating, periodicity, duty cycle and geometry using over 100 distinct gratings. The critical parameters of experimental use, such as diffraction angle and wavelength are also discussed, with an outlook to achieving optimal ultracold experimental conditions.

  19. Neutron Diffraction Study of Magnetic Ordering in Cd1-xMnxTe

    DEFF Research Database (Denmark)

    Giebultowicz, T.; Kepa, H.; Buras, B.;

    1981-01-01

    Neutron diffraction experiments were performed on Cd1−xMnxTe crystals for x=0.40, 0.60, 0.63, 0.65 and 0.70. Magnetic Bragg scattering was observed at low temperatures for xgreater-or-equal, slanted0.60 corresponding to the Type III antiferromagnetic ordering of a f.c.c. sub-lattice. The Néel tem...... temperatures decreasing with x were determined and the critical concentration xc was estimated....

  20. Electron gun for diffraction experiments on controlled molecules

    CERN Document Server

    Müller, Nele L M; Długołecki, Karol; Küpper, Jochen

    2015-01-01

    A dc electron gun, generating picosecond pulses with up to $8\\times10^{6}$ electrons per pulse, was developed. Its applicability for future time-resolved-diffraction experiments on state- and conformer-selected laser-aligned or oriented gaseous samples was characterized. The focusing electrodes were arranged in a velocity-map imaging spectrometer configuration. This allowed to directly measure the spatial and velocity distributions of the electron pulses emitted from the cathode. In combination with electron trajectory simulations, this permitted the characterization of the electron beam in terms of coherence length and pulse duration. Electron diffraction data of a thin aluminum foil illustrated the diffraction capabilities of the electron-gun setup.

  1. Neutron diffraction and magnetic investigations of the TbCo sub 4 M compounds (M = Al and Ga)

    CERN Document Server

    Zlotea, C

    2002-01-01

    The structural and magnetic features of the TbCo sub 4 M compounds (M = Al and Ga) have been studied by means of neutron powder diffraction and magnetic measurements. X-ray diffraction experiments show that the samples are single phased, crystallizing in the CaCu sub 5 -type structure. Neutron powder diffraction measurements demonstrate a preferential substitution of Al and Ga at the 3g crystallographic site of the CaCu sub 5 -type structure. Together with neutron powder diffraction investigations, magnetization measurements and x-ray powder diffraction studies performed on field-oriented samples are combined in order to clarify the effects of the Al and Ga substitutions on the magnetic features of these compounds. The modifications of the magnetic properties upon substitution are significant: a drastic decrease of the mean Co magnetic moment and of the Curie temperature is observed. Unlike what was found earlier for TbCo sub 5 , no sign of a spin reorientation transition has been observed in the present TbCo...

  2. New synchrotron powder diffraction facility for long-duration experiments

    Science.gov (United States)

    Murray, Claire A.; Potter, Jonathan; Day, Sarah J.; Baker, Annabelle R.; Thompson, Stephen P.; Kelly, Jon; Morris, Christopher G.; Tang, Chiu C.

    2017-01-01

    A new synchrotron X-ray powder diffraction instrument has been built and commissioned for long-duration experiments on beamline I11 at Diamond Light Source. The concept is unique, with design features to house multiple experiments running in parallel, in particular with specific stages for sample environments to study slow kinetic systems or processes. The instrument benefits from a high-brightness X-ray beam and a large area detector. Diffraction data from the commissioning work have shown that the objectives and criteria are met. Supported by two case studies, the results from months of measurements have demonstrated the viability of this large-scale instrument, which is the world’s first dedicated facility for long-term studies (weeks to years) using synchrotron radiation. PMID:28190992

  3. Visualizing aerosol-particle injection for diffractive-imaging experiments

    CERN Document Server

    Awel, Salah; Eckerskorn, Niko; Wiedorn, Max; Horke, Daniel A; Rode, Andrei V; Küpper, Jochen; Chapman, Henry N

    2015-01-01

    Delivering sub-micrometer particles to an intense x-ray focus is a crucial aspect of single-particle diffractive-imaging experiments at x-ray free-electron lasers. Enabling direct visualization of sub-micrometer aerosol particle streams without interfering with the operation of the particle injector can greatly improve the overall efficiency of single-particle imaging experiments by reducing the amount of time and sample consumed during measurements. We have developed in-situ non-destructive imaging diagnostics to aid real-time particle injector optimization and x-ray/particle-beam alignment, based on laser illumination schemes and fast imaging detectors. Our diagnostics are constructed to provide a non-invasive rapid feedback on injector performance during measurements, and have been demonstrated during diffraction measurements at the FLASH free-electron laser.

  4. New synchrotron powder diffraction facility for long-duration experiments.

    Science.gov (United States)

    Murray, Claire A; Potter, Jonathan; Day, Sarah J; Baker, Annabelle R; Thompson, Stephen P; Kelly, Jon; Morris, Christopher G; Yang, Sihai; Tang, Chiu C

    2017-02-01

    A new synchrotron X-ray powder diffraction instrument has been built and commissioned for long-duration experiments on beamline I11 at Diamond Light Source. The concept is unique, with design features to house multiple experiments running in parallel, in particular with specific stages for sample environments to study slow kinetic systems or processes. The instrument benefits from a high-brightness X-ray beam and a large area detector. Diffraction data from the commissioning work have shown that the objectives and criteria are met. Supported by two case studies, the results from months of measurements have demonstrated the viability of this large-scale instrument, which is the world's first dedicated facility for long-term studies (weeks to years) using synchrotron radiation.

  5. LHCb experiment magnets

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    The leading members of the LHCb magnet project, from left to right: Pierre-Ange Giudici, who organized and supervised the industrial production of the coils; Marcello Losasso, who performed the 3D calculations to optimise the magnetic field; Olivier Jamet, responsible for the 3D design; Jean Renaud, in charge of the magnet assembly, and Wilfried Flegel, project leader. The LHCb detector will investigate matter-antimatter differences in B mesons at the LHC. The coils of the detector's huge dipole magnet are seen here in April 2004.

  6. QCD and Diffraction in the ATLAS Experiment at the LHC

    CERN Document Server

    Kepka, Oldrich; Kupco, A

    2009-01-01

    This thesis is devoted to study the hard diffractive and exclusive events at the experiment ATLAS. Right after the start-up of a new proton accelerator LHC in CERN they will be identified using the rapidity gap method. We therefore developed an alternative definition of the observed energy in the ATLAS calorimeter to identify diffractive and exclusive events. During the high luminosity operation of the accelerator, forward detectors (AFP) recently proposed to be installed far from the interaction point approaching the beam at few millimeters will allow to tag the intact scattered protons in these events unambiguously. The simplest exclusive production is due to the exchange of two photons. We implemented two-photon exchanges in FPMC generator and analyzed the two-photon production of $W$ and $Z$-pairs decaying leptonically to calculate sensitivities on triple and quartic anomalous gauge couplings of electroweak boson to photons. The obtained results are remarkable mainly for the quartic couplings. Their curre...

  7. Magnetic Repulsion: An Introductory Experiment

    Science.gov (United States)

    Romer, Alfred

    1973-01-01

    Discusses the use of a balance assembled from standard laboratory components to conduct an experiment on the repulsion between two bar magnets. Includes an analysis of data on the two-pole and four-pole models. (CC)

  8. Residual stress characterization of steel TIG welds by neutron diffraction and by residual magnetic stray field mappings

    Science.gov (United States)

    Stegemann, Robert; Cabeza, Sandra; Lyamkin, Viktor; Bruno, Giovanni; Pittner, Andreas; Wimpory, Robert; Boin, Mirko; Kreutzbruck, Marc

    2017-03-01

    The residual stress distribution of tungsten inert gas welded S235JRC+C plates was determined by means of neutron diffraction (ND). Large longitudinal residual stresses with maxima around 600 MPa were found. With these results as reference, the evaluation of residual stress with high spatial resolution GMR (giant magneto resistance) sensors was discussed. The experiments performed indicate a correlation between changes in residual stresses (ND) and the normal component of local residual magnetic stray fields (GMR). Spatial variations in the magnetic field strength perpendicular to the welds are in the order of the magnetic field of the earth.

  9. Locating and Visualizing Crystals for X-Ray Diffraction Experiments.

    Science.gov (United States)

    Becker, Michael; Kissick, David J; Ogata, Craig M

    2017-01-01

    Macromolecular crystallography has advanced from using macroscopic crystals, which might be >1 mm on a side, to crystals that are essentially invisible to the naked eye, or even under a standard laboratory microscope. As crystallography requires recognizing crystals when they are produced, and then placing them in an X-ray, electron, or neutron beam, this provides challenges, particularly in the case of advanced X-ray sources, where beams have very small cross sections and crystals may be vanishingly small. Methods for visualizing crystals are reviewed here, and examples of different types of cases are presented, including: standard crystals, crystals grown in mesophase, in situ crystallography, and crystals grown for X-ray Free Electron Laser or Micro Electron Diffraction experiments. As most techniques have limitations, it is desirable to have a range of complementary techniques available to identify and locate crystals. Ideally, a given technique should not cause sample damage, but sometimes it is necessary to use techniques where damage can only be minimized. For extreme circumstances, the act of probing location may be coincident with collecting X-ray diffraction data. Future challenges and directions are also discussed.

  10. Foucault imaging and small-angle electron diffraction in controlled external magnetic fields.

    Science.gov (United States)

    Nakajima, Hiroshi; Kotani, Atsuhiro; Harada, Ken; Ishii, Yui; Mori, Shigeo

    2016-12-01

    We report a method for acquiring Foucault images and small-angle electron diffraction patterns in external magnetic fields using a conventional transmission electron microscope without any modification. In the electron optical system that we have constructed, external magnetic fields parallel to the optical axis can be controlled using the objective lens pole piece under weak excitation conditions in the Foucault mode and the diffraction mode. We observe two ferromagnetic perovskite-type manganese oxides, La0.7Sr0.3MnO3 (LSMO) and Nd0.5Sr0.5MnO3, in order to visualize magnetic domains and their magnetic responses to external magnetic fields. In rhombohedral-structured LSMO, pinning of magnetic domain walls at crystallographic twin boundaries was found to have a strong influence on the generation of new magnetic domains in external applied magnetic fields.

  11. Neutron Diffraction Studies of the Modulated Magnetic Structures of CeSb and Nd Metal

    DEFF Research Database (Denmark)

    Lebech, Bente

    1981-01-01

    The magnetic phase diagram of CeSb, which has been determined by neutron diffraction and other experimental techniques, is briefly reviewed and related to some of the theoretical models that have been developed to account for it. The results of neutron diffraction studies of Nd metal are also...

  12. Review - X-ray diffraction measurements in high magnetic fields and at high temperatures

    Directory of Open Access Journals (Sweden)

    Yoshifuru Mitsui, Keiichi Koyama and Kazuo Watanabe

    2009-01-01

    Full Text Available A system was developed measuring x-ray powder diffraction in high magnetic fields up to 5 T and at temperatures from 283 to 473 K. The stability of the temperature is within 1 K over 6 h. In order to examine the ability of the system, the high-field x-ray diffraction measurements were carried out for Si and a Ni-based ferromagnetic shape-memory alloy. The results show that the x-ray powder diffraction measurements in high magnetic fields and at high temperatures are useful for materials research.

  13. Neutron diffraction study of the magnetic structure of HoCu2

    DEFF Research Database (Denmark)

    Smetana, Z.; Sima, V.; Lebech, Bente

    1986-01-01

    Neutron diffraction measurements show that in the temperature range from 7.4 to TN=10.4 K the magnetic structure of HoCu2 is a commensurably modulated a-axis collinear structure with a wave vector q1=1/3a*. Below 7.4 K an additional structure component develops and the low temperature magnetic st...

  14. Induced magnetic anisotropy in Si-free nanocrystalline soft magnetic materials: A transmission x-ray diffraction study

    Energy Technology Data Exchange (ETDEWEB)

    Parsons, R., E-mail: rparsons01@gmail.com; Suzuki, K. [Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800 (Australia); Yanai, T. [Graduate School of Engineering, Nagasaki University, Nagasaki 852-8521 (Japan); Kishimoto, H.; Kato, A. [Toyota Motor Corporation, Mishuku, Susono, Shizuoka 410-1193 (Japan); Ohnuma, M. [Faculty and Graduate School of Engineering, Hokkaido University, Sapporo 060-8628 (Japan)

    2015-05-07

    In order to better understand the origin of field-induced anisotropy (K{sub u}) in Si-free nanocrystalline soft magnetic alloys, the lattice spacing of the bcc-Fe phase in nanocrystalline Fe{sub 94−x}Nb{sub 6}B{sub x} (x = 10, 12, 14) alloys annealed under an applied magnetic field has been investigated by X-ray diffraction in transmission geometry (t-XRD) with the diffraction vector parallel and perpendicular to the field direction. The saturation magnetostriction (λ{sub s}) of nanocrystalline Fe{sub 94−x}Nb{sub 6}B{sub x} was found to increase linearly with the volume fraction of the residual amorphous phase and is well described by taking into account the volume-weighted average of two local λ{sub s} values for the bcc-Fe nanocrystallites (−5 ± 2 ppm) and the residual amorphous matrix (+8 ± 2 ppm). The lattice distortion required to produce the measured K{sub u} values (∼100 J/m{sup 3}) was estimated via the inverse magnetostrictive effect using the measured λ{sub s} values and was compared to the lattice spacing estimations made by t-XRD. The lattice strain required to produce K{sub u} under the magnetoelastic model was not observed by the t-XRD experiments and so the findings of this study suggest that the origin of magnetic field induced K{sub u} cannot be explained through the magnetoelastic effect.

  15. Two new tensile devices for X-ray diffraction experiments

    Energy Technology Data Exchange (ETDEWEB)

    Freri, N.; Tintori, A.; Depero, L.E.; Sangaletti, L. [Brescia Univ. (Italy); Cernuschi, F.; Ghia, S. [Ente Nazionale per l`Energia Elettrica, Milan (Italy)

    1995-12-01

    Two tensile devices were designed to be used with parallel beam and parafocusing-geometry diffractometers. In thefirst case the device was designed to be attached to a strainflex diffractometer by Rigaku Inc., dedicated to stress analysis and commonly used in metallurgical industry. Since the sample does not move during the measurement, the tensile device can be kept fixed on the experimental table. The device design takes into account the steric hindrance by moving parts of diffractometer. The maximun load that can be applied to the sample is 60.000 N. An attachement to a Siemens D5000 diffractometer with Eulerian cradle has also benn designed for applying a load up tp 6000 N to a sample in the parafocusing-geometry. The installation does not require a re-alignment of the diffractometer. In both cases strain gages were applied to both sides of the specimen for the simultaneous determination of the macroscopic strains. Experiments based on the use of these devices are planned to determine the crystallographic elastic constants and study the influence of the microstructure on the mechanical behaviour of residual stresses in the zone of almost static stresses as well as the influence of residual stresses on uniaxially loaded samples. In addition, by using these devices, it is possible to measure the unstressed d-0 spacings providing useful information in the neutron diffraction study fo stress fields in steel samples.

  16. Soft x-ray resonant diffraction study of magnetic and orbital correlations in a manganite near half doping

    NARCIS (Netherlands)

    Thomas, KJ; Grenier, S; Kim, YJ; Abbamonte, P; Rusydi, A; Tomioka, Y; Tokura, Y; McMorrow, DF; Sawatzky, G; van Veenendaal, M; Hill, J.P.; Venema, L.C.

    2004-01-01

    We have utilized resonant x-ray diffraction at the Mn L(II,III) edges in order to directly compare magnetic and orbital correlations in Pr(0.6)Ca(0.4)MnO(3). Comparing the widths of the magnetic and orbital diffraction peaks, we find that the magnetic correlation length exceeds that of the orbital o

  17. Magnetic and electronic orderings in orthorhombic RMnO3 (R=Tm, Lu) studied by resonant soft x-ray powder diffraction

    Science.gov (United States)

    Garganourakis, M.; Bodenthin, Y.; de Souza, R. A.; Scagnoli, V.; Dönni, A.; Tachibana, M.; Kitazawa, H.; Takayama-Muromachi, E.; Staub, U.

    2012-08-01

    Resonant soft x-ray powder diffraction experiments on orthorhombic TmMnO3 and LuMnO3 are presented. Experiments were performed in the vicinity of the Tm M5 and the Mn L2,3 edges to study the Tm and Mn magnetic moments, respectively. These experiments show that for the heavy rare-earth perovskite with an E-type ordered ground state, the Tm magnetic moments order already in the nonferroelectric incommensurate magnetic phase. Additionally, deviations from the collinear E-type Mn magnetic structure at low temperatures are found for both compounds. These experiments show the power of resonant soft x-ray diffraction, extended to polycrystalline 4f materials.

  18. Magnetic structure of Pr6Fe13Ge studied by Mossbauer effect and neutron diffraction

    Institute of Scientific and Technical Information of China (English)

    王芳卫; 张泮霖; 严启伟; 宫华扬

    2000-01-01

    Magnetic structure of Pr6Fe13Ge at room temperature has been investigated by magnetic measurement, Mossbauer effect and neutron diffraction. Magnetic atoms are closely packed up and down the mirror planes at z = 0 and 1/2 and separated by the non-magnetic atoms located on the planes at z= 1/4 and 3/4, which constructs an M/NM/M sandwich structure (M: magnetic, NM: non-magnetic). The intralayer magnetic moments couple ferromagnetically and are out of ab plane at a small angle so as to form a component along c-axis. The interlayer coupling is antiferromagnetic for the ab component while ferromagnetic for the c component.

  19. Complex magnetic ordering in CeFe1.76 studied by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Jayasekara, Wageesha T [Ames Laboratory; Tian, W [Oak Ridge National Laboratory; Hodovanets, Halyna [Ames Laboratory; Canfield, Paul C [Ames Laboratory; Bud' ko, Serguei L [Ames Laboratory; Kreyssig, Andreas [Ames Laboratory; Goldman, Alan I [Ames Laboratory

    2014-10-01

    Neutron diffraction measurements on a single crystal of CeGe1.76 reveal a complex series of magnetic transitions at low temperature. At TN≈7 K, there is a transition from a paramagnetic state at higher temperature to an incommensurate magnetic structure characterized by a magnetic propagation vector (0 0 τ) with τ≈1/4 and the magnetic moment along the a axis of the orthorhombic unit cell. Below TLI≈5 K, the magnetic structure locks in to a commensurate structure with τ=1/4 and the magnetic moment remains along the a axis. Below T≈4 K, we find additional half-integer and integer indexed magnetic Bragg peaks consistent with a second commensurately ordered antiferromagnetic state.

  20. Mössbauer, magnetization and X-ray diffraction characterization methods for iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Gabbasov, Raul, E-mail: gabbasov-raul@yandex.ru [National Research Center “Kurchatov Institute”, Moscow (Russian Federation); Polikarpov, Michael; Cherepanov, Valery [National Research Center “Kurchatov Institute”, Moscow (Russian Federation); Chuev, Michael; Mischenko, Iliya; Lomov, Andrey [Institute of Physics and Technology, Russian Academy of Sciences, Moscow (Russian Federation); Wang, Andrew [Ocean NanoTech. Springdale, AR (United States); Panchenko, Vladislav [National Research Center “Kurchatov Institute”, Moscow (Russian Federation)

    2015-04-15

    Water soluble magnetite iron oxide nanoparticles with oleic polymer coating and average diameters in the range of 5–25 nm, previously determined by TEM, were characterized using Mössbauer, magnetization and X-ray diffraction measurements. Comparative analysis of the results demonstrated a large diversity of magnetic relaxation regimes. Analysis showed the presence of an additional impurity component in the 25 nm nanoparticles, with principally different magnetic nature at the magnetite core. In some cases, X-ray diffraction measurements were unable to estimate the size of the magnetic core and Mössbauer data were necessary for the correct interpretation of the experimental results. - Highlights: • KV parameter, obtained from Mössbauer spectra can be used for nanoparticle size characterization. • Mössbauer spectra of 10–25 nm nanoparticles can be effectively described by ferromagnetic model. • Surface impurities can cause incorrect nanoparticle size determination.

  1. Geometrically frustrated magnetic structures of the heavy-fermion compound CePdAl studied by powder neutron diffraction

    Science.gov (United States)

    Dönni, A.; Ehlers, G.; Maletta, H.; Fischer, P.; Kitazawa, H.; Zolliker, M.

    1996-12-01

    The heavy-fermion compound CePdAl with ZrNiAl-type crystal structure (hexagonal space group 0953-8984/8/50/043/img8) was investigated by powder neutron diffraction. The triangular coordination symmetry of magnetic Ce atoms on site 3f gives rise to geometrical frustration. CePdAl orders below 0953-8984/8/50/043/img9 with an incommensurate antiferromagnetic propagation vector 0953-8984/8/50/043/img10, and a longitudinal sine-wave (LSW) modulated spin arrangement. Magnetically ordered moments at Ce(1) and Ce(3) coexist with frustrated disordered moments at Ce(2). The experimentally determined magnetic structure is in agreement with group theoretical symmetry analysis considerations, calculated by the program MODY, which confirm that for Ce(2) an ordered magnetic moment parallel to the magnetically easy c-axis is forbidden by symmetry. Further low-temperature experiments give evidence for a second magnetic phase transition in CePdAl between 0.6 and 1.3 K. Magnetic structures of CePdAl are compared with those of the isostructural compound TbNiAl, where a non-zero ordered magnetic moment for the geometrically frustrated Tb(2) atoms is allowed by symmetry.

  2. Study of diffractive processes at the ATLAS Experiment

    CERN Document Server

    Kus, Vlastimil

    A data sample of $pp$ collisions corresponding to an integrated luminosity of 6.75 $\\mathrm{nb}^{-1}$ was collected at $\\sqrt{s} = 7$ TeV using the ATLAS detector at the Large Hadron Collider. Collision events with at least two jets with $p_{\\mathrm{T}}>20$ GeV are used to measure the differential cross section of the diffractive dijet production as a function of the rapidity gap size $\\Delta\\eta^{\\mathrm{F}}$, the largest forward region extending from $|\\eta| = 4.8$ devoid of particle activity above threshold momentum cuts, and an estimator of the fractional momentum loss of the scattered proton assuming the single diffractive dissociation ($pp \\rightarrow pX$), $\\tilde\\xi^{\\pm}$. Comparisons with various Monte Carlo models reveal that though the region of small $\\tilde\\xi^{\\pm}$ and large rapidity gaps is dominated by diffraction, a contribution form non-diffractive events cannot be neglected. The rapidity gap survival probability is estimated based on data to Monte Carlo comparisons in the $-3.2 2$ require...

  3. Teaching Diffraction of Light and Electrons: Classroom Analogies to Classic Experiments

    Science.gov (United States)

    Velentzas, Athanasios

    2014-01-01

    Diffraction and interference are phenomena that demonstrate the wave nature of light and of particles. Experiments relating to the diffraction/interference of light can easily be carried out in an educational lab, but it may be impossible to perform experiments involving electrons because of the lack of specialized equipment needed for such…

  4. Magnetic structures of R(Cu, Ni)2 compounds (R = heavy rare earth) studied by neutron diffraction

    Science.gov (United States)

    Smetana, Z.; Šíma, V.

    1985-11-01

    Magnetics structures of powdered orthorhombic R(Cu, Ni)2 compounds (R = heavy rare earth) determined by neutron diffraction are described. The influence of magnetocrystalline anisotropy and exchange interactions on the type of magnetic ordering is discussed.

  5. Magnet operating experience review for fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Cadwallader, L.C.

    1991-11-01

    This report presents a review of magnet operating experiences for normal-conducting and superconducting magnets from fusion, particle accelerator, medical technology, and magnetohydrodynamics research areas. Safety relevant magnet operating experiences are presented to provide feedback on field performance of existing designs and to point out the operational safety concerns. Quantitative estimates of magnet component failure rates and accident event frequencies are also presented, based on field experience and on performance of similar components in other industries.

  6. Magnet operating experience review for fusion applications

    Energy Technology Data Exchange (ETDEWEB)

    Cadwallader, L.C.

    1991-11-01

    This report presents a review of magnet operating experiences for normal-conducting and superconducting magnets from fusion, particle accelerator, medical technology, and magnetohydrodynamics research areas. Safety relevant magnet operating experiences are presented to provide feedback on field performance of existing designs and to point out the operational safety concerns. Quantitative estimates of magnet component failure rates and accident event frequencies are also presented, based on field experience and on performance of similar components in other industries.

  7. Neutron diffraction studies of magnetic-shape memory Ni-Mn-Ga single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Heczko, Oleg [Laboratory of Materials Science, Helsinki University of Technology, Vuorimiehentie 2A, P.O. Box 6200, FI-02015 TKK, Espoo (Finland)]. E-mail: oleg.heczko@tkk.fi; Prokes, Karel [Berlin Neutron Scattering Center, Hahn-Meitner-Institut Berlin, Glienicker Strasse 100, D-14109 Berlin (Wannsee) (Germany); Hannula, Simo-Pekka [Laboratory of Materials Science, Helsinki University of Technology, Vuorimiehentie 2A, P.O. Box 6200, FI-02015 TKK, Espoo (Finland)

    2007-09-15

    Neutron diffraction of single crystal of the typical example of magnetic-shape memory (MSM) alloy Ni{sub 49.7}Mn{sub 29.3}Ga{sub 21} was carried out with a 2D position sensitive detector. The quality and inhomogeneity of the single crystal and martensite variant distribution was studied using {omega}-scan of selected nuclear Bragg reflections. The neutron diffraction reveals split of the (2 0 0) reflection of major martensite variant and large structural inhomogeneities in martensite phase. Using measurement in reciprocal space, we recorded a set of reflections that appear due to structural modulation (5 M) of the martensite, however, the set seems to be incomplete with missing or very weak reflections of second order compared with X-ray diffraction. The line of the magnetic reflection arising from the supposed antiferromagnetic ordering of the excess Mn atoms was very weak and it is difficult to discern from the background.

  8. Neutron diffraction studies of magnetic-shape memory Ni-Mn-Ga single crystal

    Science.gov (United States)

    Heczko, Oleg; Prokes, Karel; Hannula, Simo-Pekka

    2007-09-01

    Neutron diffraction of single crystal of the typical example of magnetic-shape memory (MSM) alloy Ni 49.7Mn 29.3Ga 21 was carried out with a 2D position sensitive detector. The quality and inhomogeneity of the single crystal and martensite variant distribution was studied using ω-scan of selected nuclear Bragg reflections. The neutron diffraction reveals split of the (2 0 0) reflection of major martensite variant and large structural inhomogeneities in martensite phase. Using measurement in reciprocal space, we recorded a set of reflections that appear due to structural modulation (5 M) of the martensite, however, the set seems to be incomplete with missing or very weak reflections of second order compared with X-ray diffraction. The line of the magnetic reflection arising from the supposed antiferromagnetic ordering of the excess Mn atoms was very weak and it is difficult to discern from the background.

  9. Neutron diffraction studies on magnetic properties of Ca5Ni4V6O24

    Science.gov (United States)

    Sharma, Shivani; Singh, Kiran; Lalla, N. P.; Suard, E.; Simon, Ch.

    2017-01-01

    The temperature dependent neutron powder diffraction (NPD) and magnetization measurements of vanadium based garnet Ca5Ni4V6O24 (CNVO) have been performed to explore its crystal and magnetic structures. The magnetization results illustrate two magnetic anomalies at 7 and 4 K. The Rietveld analysis of room temperature x-ray diffraction and NPD data confirms its Ia-3d crystal structure. The temperature dependent NPD shows the emergence of magnetic reflections below 7 K whose intensity keeps on increasing with decreasing temperature down to 1.5 K. The crystal structure remains cubic down to 1.5 K. Rietveld analysis reveals that below 7 K, the Ni moments in CNVO undergo a commensurate collinear A-type antiferromagnetic ordering with propagation vector k=(0,0,0) and the per site ordered moment of Ni2+ is 1.69±0.05 μB. Absence of any additional magnetic or nuclear reflections below 4 K confirms that the nuclear and magnetic structures remain invariant across the 4 K magnetic anomaly.

  10. Focused azimuthally polarized vector beam and spatial magnetic resolution below the diffraction limit

    Science.gov (United States)

    Veysi, Mehdi; Guclu, Caner; Capolino, Filippo

    2016-11-01

    An azimuthally electric-polarized vector beam (APB), with a polarization vortex, has a salient feature that it contains a magnetic-dominant region within which electric field ideally has a null while longitudinal magnetic field is maximum. Fresnel diffraction theory and plane-wave spectral (PWS) calculations are applied to quantify field features of such a beam upon focusing through a lens. The diffraction-limited full width at half maximum (FWHM) of the beam's longitudinal magnetic field intensity profile and complementary FWHM (CFWHM) of the beam's annular-shaped total electric field intensity profile are examined at the lens's focal plane as a function of the lens's paraxial focal distance. Then, we place a subwavelength dense dielectric Mie scatterer in the minimum-waist plane of a self-standing converging APB and demonstrate for the first time that a very high resolution magnetic field at optical frequency is achieved with total magnetic field FWHM of 0.23{\\lambda} (i.e., magnetic field spot area of 0.04{\\lambda}^2) within a magnetic-dominant region. The theory shown here is valuable for development of optical microscopy and spectroscopy systems based on magnetic dipolar transitions which are in general much weaker than their electric counterparts.

  11. Diffraction by a grating made of a uniaxial dielectric-magnetic medium exhibiting negative refraction

    Energy Technology Data Exchange (ETDEWEB)

    Depine, Ricardo A [Grupo de Electromagnetismo Aplicado, Departamento de FIsica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina); Lakhtakia, Akhlesh [CATMAS-Computational and Theoretical Materials Sciences Group, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802-6812 (United States); Department of Physics, Imperial College, London SW7 2BZ (United Kingdom)

    2005-08-01

    Diffraction of linearly polarized plane electromagnetic waves at the periodically corrugated boundary of vacuum and a linear, homogeneous, uniaxial, dielectric-magnetic medium is formulated as a boundary-value problem and solved using the Rayleigh method. The focus is on situations where the diffracted fields maintain the same polarization state as the s- or p-polarized incident plane wave. Attention is paid to two classes of diffracting media: those with negative definite permittivity and permeability tensors, and those with indefinite permittivity and permeability tensors. For the situations investigated, whereas the dispersion equations in the diffracting medium turn out to be elliptic for the first class of diffracting media, they are hyperbolic for the second class. Examples are reported with the first class of diffracting media of instances when the grating acts either as a positively refracting interface or as a negatively refracting interface. For the second class of diffracting media, hyperbolic dispersion equations imply the possibility of an infinite number of refraction channels.

  12. Strategy for realizing magnetic field enhancement based on diffraction coupling of magnetic plasmon resonances in embedded metamaterials.

    Science.gov (United States)

    Chen, Jing; Mao, Peng; Xu, Rongqing; Tang, Chaojun; Liu, Yuanjian; Wang, Qiugu; Zhang, Labao

    2015-06-15

    We have demonstrated a straightforward strategy to realize magnetic field enhancement through diffraction coupling of magnetic plasmon (MP) resonances by embedding the metamaterials consisting of a planar rectangular array of U-shaped metallic split-ring resonators (SRRs) into the substrate. Our method provides a more homogeneous dielectric background allowing stronger diffraction coupling of MP resonances among SRRs leading to strong suppression of the radiative damping. We observe that compared to the on-substrate metamaterials, the embedded ones lead to a narrow-band hybridized MP mode, which results from the interference between MP resonances in individual SRRs and an in-plane propagating collective surface mode arising from light diffraction. Associated with the excitation of this hybridized MP mode, a twenty-seven times enhancement of magnetic fields within the inner area of the SRRs is achieved as compared with the pure MP resonance. Moreover, we also found that besides the above requirement of homogeneous dielectric background, only a collective surface mode with its magnetic field of the same direction as the induced magnetic moment in the SRRs could mediate the excitation of such a hybridized MP mode.

  13. Magnetic Structure of Goethite α-FeOOH: A Neutron Diffraction Study

    Science.gov (United States)

    Zepeda-Alarcon, E.; Nakotte, H.; Vogel, S. C.; Wenk, H.

    2013-12-01

    Goethite (α-FeOOH) is found in diverse natural ecosystems, it is by far the most common oxyhydroxide in terrestrial soils, sediments and clays and an important mineral in the biogeochemical cycle of iron at the Earth's surface. Neutron diffraction studies have found that the iron magnetic moments are collinear in a two sublattice antiferromagnetic structure, aligned parallel to the c axis in space group Pbnm (Forsyth et. al. 1968). However, goethite shows superparamagnetic behavior and also a weak ferromagnetic component that has been attributed to the presence of lattice distortions. It is thought that these changes in magnetic ordering could be due to a 13° canting of the magnetic moment with respect to the c-axis, which enables the flipping of the spins due to small perturbations in the lattice (Coey et. al. 1995). In this study we used neutron diffraction at HIPPO and NPDF beamlines at LANSCE of Los Alamos National Laboratory on a powder of natural goethite provided by A. Gualtieri. The nuclear and magnetic structures were determined by means of a Rietveld refinement with GSAS and it was found that the spins of the iron atoms are aligned parallel to the c-axis, with no evidence of spin canting. The net magnetic moment is lower than what has previously been found. These results provide further insight into the magnetic ordering of this mineral and can be important in understanding the physical processes responsible for goethite's intriguing magnetic behavior.

  14. Crystallographic and magnetic structures of Pr6Fe13Ge studied by powder neutron diffraction

    Institute of Scientific and Technical Information of China (English)

    Wang Fang-Wei; Zhang Pan-Lin; Shen Bao-Gen; Yan Qi-Wei

    2004-01-01

    Crystallographic and magnetic structures of Pr6Fel3Ge have been investigated by high-resolution powder neutron diffraction in the temperature range of 10-300 K. The magnetic structure consists of ferromagnetic Pr6Fe13 slabs that alternate antiferromagnetically, along c, with the next Pr6Fe13 slab separated by a non-magnetic Ge layer. The magnetic moments lie within the ab-planes. The propagation vector of this structure is k=(001) with respect to the conventional reciprocal lattice of the Ⅰ-centred structure. However, the temperature-dependence of neutron-scattering intensity of the (110) Bragg peak, very similar to the temperature-dependent magnetization measured by SQUID magnetometer,indicates that a small c-axis ferromagnetic component should be added to the above antiferromagnetic model.

  15. Magnetization distribution in paramagnetic CoO: a polarized neutron diffraction study

    CERN Document Server

    Kernavanois, N; Brown, P J; Henry, J Y; Lelievre-Berna, E

    2003-01-01

    Unpolarized and polarized neutron diffraction by a single crystal have been used to study the magnetization distribution in the paramagnetic phase of cobalt oxide CoO. Highly accurate magnetic structure factors have been measured using the classical polarized beam method. A detailed description of the magnetization distribution is presented. The magnetization around the cobalt site has a radial distribution which is contracted by approx = 5% with respect to that of the free ion and a symmetry which approximates more closely to e sub g than to the form t sub 2 sub g sup 5 /e sub g sup 2 expected for the Co sup 2 sup + 3d sup 7 configuration. A significant magnetization, corresponding to some 8% of the total moment, is found at the oxygen site.

  16. Dijets in diffractive photoproduction measured with the ZEUS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Renner, R.

    2006-10-15

    The diffractive photoproduction of dijets in electron-proton scattering has been studied using 77.1 pb{sup -1} of data taken with the ZEUS detector at HERA. The measurements have been made at a centre-of- mass energy {radical}s=318 GeV in the kinematic range 0.2diffractive exchange. The jets have been reconstructed using the k{sub T} algorithm. The two jets with the highest transversal energy have been required to satisfy E{sub T}>7.5 and 6.5 GeV, respectively, and to be in the pseudorapidity range -1.5<{eta}<1.5. Differential cross sections have been measured and been confronted with the predictions from leading order Monte Carlo simulations and next-to-leading order QCD calculations. (orig.)

  17. Crystalline, mixed-valence manganese analogue of prussian blue: magnetic, spectroscopic, X-ray and neutron diffraction studies.

    Science.gov (United States)

    Franz, Patrick; Ambrus, Christina; Hauser, Andreas; Chernyshov, Dmitry; Hostettler, Marc; Hauser, Jürg; Keller, Lukas; Krämer, Karl; Stoeckli-Evans, Helen; Pattison, Philip; Bürgi, Hans-Beat; Decurtins, Silvio

    2004-12-22

    The compound of stoichiometry Mn(II)3[Mn(III)(CN)6]2.zH2O (z = 12-16) (1) forms air-stable, transparent red crystals. Low-temperature single crystal optical spectroscopy and single crystal X-ray diffraction provide compelling evidence for N-bonded high-spin manganese(II), and C-bonded low-spin manganese(III) ions arranged in a disordered, face-centered cubic lattice analogous to that of Prussian Blue. X-ray and neutron diffraction show structured diffuse scattering indicative of partially correlated (rather than random) substitutions of [Mn(III)(CN)6] ions by (H2O)6 clusters. Magnetic susceptibility measurements and elastic neutron scattering experiments indicate a ferrimagnetic structure below the critical temperature Tc = 35.5 K.

  18. Focused Azimuthally E-Polarized Vector Beam and Spatial Magnetic Resolution below the Diffraction Limit

    CERN Document Server

    Veysi, Mehdi; Capolino, Filippo

    2016-01-01

    An azimuthally E-polarized vector beam (AEVB) has a salient feature that it contains a magnetic-dominant region within which electric field has a null and longitudinal magnetic field is maximum. Fresnel diffraction theory and plane-wave spectral (PWS) calculations are applied to quantify the field features of such a beam upon focusing through a lens. The diffraction-limited full width at half maximum (FWHM) of the beams longitudinal magnetic field intensity profile and complementary FWHM (CFWHM) of the beam's annular-shaped total electric field intensity profile are calculated at the lens's focal plane as a function of the lens's paraxial focal distance. Subsequently, we demonstrate, for the first time, that a very high resolution magnetic field at optical frequency with the total magnetic field FWHM of 0.23{\\lambda}(magnetic field spot size of 0.04{\\lambda}^2) can be achieved by placing a subwavelength dense dielectric Mie scatterer in the minimum-waist plane of a self-standing converging AEVB. The theory sh...

  19. Phase quantification in nanobainite via magnetic measurements and X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Solano-Alvarez, W., E-mail: ws298@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge (United Kingdom); Abreu, H.F.G. [Departamento de Engenharia Metalúrgica e de Materiais, Universidade Federal do Ceará, Fortaleza (Brazil); Silva, M.R. da [Instituto de Física e Química, Universidade Federal de Itajubá, Itajubá, Minas Gerais (Brazil); Peet, M.J. [Department of Materials Science and Metallurgy, University of Cambridge (United Kingdom)

    2015-03-15

    Accurate phase quantification of nanostructured bainitic steel is of importance because of the nature of its percolating structure that controls many of its mechanical properties. X-ray diffraction is the technique of choice for such analysis, but magnetic methods can be more rapid and less sensitive to defect structures. In this study, the phase volume fractions measured using both of these techniques for the specific mixtures associated with nanostructured bainite have been compared and contrasted. An expression which relates the volume fraction and the saturation magnetization is obtained and its form is found to be consistent with previous work done on duplex stainless steels and TRIP steels. The fitting constants used in many of such analyses vary significantly so an attempt is made to rationalize the differences by considering the factors that determine the intrinsic saturation magnetization of ferrite. - Author-Highlights: • Magnetic phase quantification of nanobainite is presented for the first time. • Results are compared with x-ray diffraction. • Expression obtained that relates ferrite fraction and saturation magnetization. • Equation derived to calculate intrinsic saturation magnetization of ferrites. • These values agree with experimental data of the literature.

  20. Magnetization, electrical resistivity, thermopower, and neutron diffraction in HoCu/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Gratz, E. (Technische Univ., Vienna (Austria)); Sechovsky, V.; Sima, V.; Smetana, Z. (Karlova Univ., Prague (Czechoslovakia). Matematicky Ustav); Stroem-Olson, J.O. (McGill Univ., Montreal, Quebec (Canada). Dept. of Physics)

    1982-05-01

    HoCu/sub 2/ shows a Curie-Weiss susceptibility above 15 K. The paramagnetic moment and the paramagnetic Curie temperature is (10.1 +- 0.1) ..mu../sub B//H/sub 0/ and (4 +- 2) K, respectively. Two cusps (at about 7 and 10 K) are seen in the magnetization versus temperature curve. These cusps reflect a change of the magnetic structure and the Neel temperature. The influence of conduction electron scattering on the localized 4f moments is estimated for the resistivity and the thermopower. Neutron diffraction measurements show that the antiferromagnetic structure is incommensurate with the crystal lattice.

  1. Interrupted Magnetic First Order Transitions and Kinetic Arrest probed with In-field Neutron Diffraction

    Science.gov (United States)

    Siruguri, V.; Kaushik, S. D.; Rayaprol, S.; Babu, P. D.; Chaddah, P.; Sampathkumaran, E. V.; Hoser, A.; Ritter, C.

    2016-09-01

    In-field neutron diffraction studies were carried out on two compounds that exhibit magnetic first order phase transitions (FOPT). It is shown that the FOPT can be interrupted by an external magnetic field, resulting in a coexistence of kinetically arrested metastable states and equilibrium phases. Use of a novel protocol CHUF (Cooling and Heating under Unequal Fields) helps to determine the coexisting phase fractions and also to observe the devitrification of the kinetically arrested phase into the equilibrium phase, in a manner similar to that found in structural glassy systems.

  2. Investigation of the commensurate magnetic structure in the heavy-fermion compound CePt2In7 using magnetic resonant x-ray diffraction

    Science.gov (United States)

    Gauthier, Nicolas; Wermeille, Didier; Casati, Nicola; Sakai, Hironori; Baumbach, Ryan E.; Bauer, Eric D.; White, Jonathan S.

    2017-08-01

    We investigated the magnetic structure of the heavy-fermion compound CePt2In7 below TN=5.34 (2 ) K using magnetic resonant x-ray diffraction at ambient pressure. The magnetic order is characterized by a commensurate propagation vector k1 /2=(1/2 ,1/2 ,1/2 ) with spins lying in the basal plane. Our measurements did not reveal the presence of an incommensurate order propagating along the high-symmetry directions in reciprocal space but cannot exclude other incommensurate modulations or weak scattering intensities. The observed commensurate order can be described equivalently by either a single-k structure or by a multi-k structure. Furthermore we explain how a commensurate-only ordering may explain the broad distribution of internal fields observed in nuclear quadrupolar resonance experiments [Sakai et al., Phys. Rev. B 83, 140408 (2011), 10.1103/PhysRevB.83.140408] that was previously attributed to an incommensurate order. We also report powder x-ray diffraction showing that the crystallographic structure of CePt2In7 changes monotonically with pressure up to P =7.3 GPa at room temperature. The determined bulk modulus B0=81.1 (3 ) GPa is similar to those of the Ce-115 family. Broad diffraction peaks confirm the presence of pronounced strain in polycrystalline samples of CePt2In7 . We discuss how strain effects can lead to different electronic and magnetic properties between polycrystalline and single crystal samples.

  3. Simultaneous structural and magnetic transitions in YFe 4Ge 2 studied by neutron diffraction and magnetic measurements

    Science.gov (United States)

    Schobinger-Papamantellos, P.; Rodríguez-Carvajal, J.; André, G.; Duong, N. P.; Buschow, K. H. J.; Tolédano, P.

    2001-10-01

    The magnetic behaviour of the tetragonal YFe 4Ge 2 compound has been studied by neutron diffraction and bulk magnetisation measurements. Magnetic ordering occurs below T N=43.5 K simultaneously with a structural transition from tetragonal P4 2/mnm→Pnnm to orthorhombic symmetry. Both transitions are of first order. The symmetry breaking is connected with primary displacive order parameters involving shifts of the Fe atoms. The Fe site splits into two sites in Pnnm, the shifts of the Fe atoms with respect to the tetragonal phase have opposite signs along the a (dilatation) and b (contraction) axes. This induces the symmetry breaking tensile strains. The planar canted antiferromagnetic arrangement with eight sublattices is the ground state associated with a magnetic energy involving isotropic exchange and anisotropic (relativistic) interactions. The magnetic structure is invariant under the magnetic space group P{2 1}/{n' } {2 1}/{n' } {2 1}/{m' } ( Sh58399) . The moments of the two orbits have the same value. At 1.5 K the Fe moment equals 0.63(4) μB/Fe atom. The YFe 4Ge 2 magnetostructural phenomena are compared to the more complex analogue of the ErFe 4Ge 2 compound. The structural and magnetic transitions are described phenomenologically within a Landau-Dzialoshinski approach which assumes a triggering mechanism, in which the spontaneous strain is triggered by the exchange contribution to the magnetic ordering.

  4. Magnetic octupole order in Ce0.7La0.3B6: A polarized neutron diffraction study

    Science.gov (United States)

    Kuwahara, K.; Iwasa, K.; Kohgi, M.; Aso, N.; Sera, M.; Iga, F.; Matsuura, M.; Hirota, K.

    2009-09-01

    Recently, in phase IV of CexLa1-xB6, weak but distinct superlattice reflections from the order parameter of phase IV have been detected by our unpolarized neutron scattering experiment [K. Kuwahara, K. Iwasa, M. Kohgi, N. Aso, M. Sera, F. Iga, J. Phys. Soc. Japan 76 (2007) 093702]. The scattering vector dependence of the intensity of superlattice reflections is quite unusual; the intensity is stronger for high scattering vectors. This result strongly indicates that the order parameter of phase IV is the magnetic octupole. However, the possibility that the observed superlattice reflections are due to lattice distortions could not be completely ruled out only on the basis of the unpolarized neutron scattering experiment. To confirm that the superlattice reflections are magnetic, therefore, we have performed a single crystal polarized neutron diffraction experiment on Ce0.7La0.3B6. The obtained result has clearly shown that the time reversal symmetry is broken by the order parameter of phase IV. This is further evidence for the magnetic octupole order in CexLa1-xB6.

  5. Magnetic structure study of antiferromagnet NpPtGa{sub 5} by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Jonen, S. [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan)], E-mail: jonen.shintaro@jaea.go.jp; Metoki, N. [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Yamamoto, E. [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Homma, Y.; Aoki, D. [Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Shiokawa, Y. [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Onuki, Y. [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Naka, Ibaraki 319-1195 (Japan); Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan)

    2008-01-10

    The magnetic structure of NpPtGa{sub 5}was investigated by neutron diffraction. NpPtGa{sub 5} exhibits an A-type antiferromagnetic structure with propagation vector q{sup {yields}}=(0,0,1/2) below T{sub N}=26 K. The estimated Np magnetic moment is 0.38(5) {mu}{sub B}, and it is oriented parallel to the <100> direction. This small moment would be consistent with the large {gamma}=123 mJ/(K{sup 2} mol), indicative of the heavy fermion nature. The field-induced anomaly in the magnetic susceptibility is clarified to be a signature for an antiferromagnetic domain change between multi-domains to single-domain states.

  6. Neutron diffraction studies of the low-temperature magnetic structure of hexagonal FeGe

    DEFF Research Database (Denmark)

    Bernhard, J.; Lebech, Bente; Beckman, O.

    1984-01-01

    The magnetic structure of the hexagonal polymorph of FeGe has been investigated by means of neutron diffraction on single crystals at low temperature and for magnetic fields applied perpendicular to the c axis. Between 410 and approximately 55K the magnetic structure is collinear c......-axis antiferromagnetic. Below approximately 55K the structure changes to c-axis double-cone antiferromagnetic with an inter-layer turn angle for the basal-plane moment component of 194.4 degrees , independent of temperature and applied field. The cone half-angle increases with decreasing temperature to approximately 14...... degrees at 4.2K, but its temperature dependence shows a pronounced kink at 30K, indicating a phase change at this temperature. At 4.2K the authors observe an anomalous decrease of the basal-plane moment component at a critical field (B perpendicular to c) of 1.4 T. As the temperature is increased...

  7. Plasmonic localized heating beyond the diffraction limit via magnetic polariton excitation

    Science.gov (United States)

    Alshehri, Hassan; Ying, Xiaoyan; Wang, Hao; Wang, Liping

    2016-09-01

    Optical localized heating in the nanoscale has recently attracted great attention due to its unique small hot spot size with high energy. However, the hot spot size is conventionally constrained by the diffraction limit. Plasmonic localized heating can provide solutions to this limitation in nanoscale patterning, cancer treatment, and data storage. Plasmonic approaches to overcome the diffraction limit in hot spot size have mainly utilized the excitation of surface plasmon or localized surface plasmon resonance. However, achieving plasmonic localized heating by the excitation of magnetic polariton has not been researched extensively yet. In this work, we numerically investigated the optical response of a nanoscale metamaterial composed of a gold nanowire array and a gold film separated by an ultrathin polymer spacer using ANSYS High Frequency Structural Simulator. A strong absorption peak at the wavelength of 760 nm was exhibited, and the underlying physical mechanism for the strong absorption was verified via the local electromagnetic field distribution to be magnetic resonance excitation. An inductor-capacitor circuit model was used to predict the magnetic resonance wavelength and compare with the numerical results for varied geometrical parameters. Volume loss density due to the strong local optical energy confinement was transferred as heat generation to an ANSYS thermal solver to obtain the local temperature profile. The steady state temperature profile shows an average temperature of 145 °C confined in a local area as small as 33 nm within the spacer, with a full-width at half-maximum of 50 nm along the x-direction. Moreover, the temperature rise from ambient drops to half its maximum value at a distance of 5 nm from the top of the spacer along the z-direction. This clearly demonstrates plasmonic localized heating beyond the diffraction limit via magnetic polariton excitation. Furthermore, the transient temperature profile shows that the system reached

  8. Neutron Diffraction Study on the Magnetic Structure of Pr6Fe13Sn

    Directory of Open Access Journals (Sweden)

    Suharyana

    2010-04-01

    Full Text Available We have successfully prepared a Pr6Fe13Sn sample by employing argon arc melting. The crystal structure of the sample has been examined by an x-ray diffraction. The x-ray pattern reveals that the sample crystallize in the tetragonal Nd6Fe13Si structure type with space group I4/mcm. Neutron diffraction at 150K performed on a powder sample shows a collinear antiferromagnetic ordering of the Fe and Pr sublattices with the wave vector (0, 0, 1 and an Ip type magnetic lattice with anti-centering translation. The main axis of antiferromagnetism is restricted to the (0 0 1 plane. The average refined Fe moments at 150 K is (2.0±0.4 µB whereas the Pr moments are (2.1±0.4 and (1.9±0.4 µB for the 8f and 16l sites, respectively

  9. Crystal and magnetic structures of Cr1/3NbSe2 from neutron diffraction

    Science.gov (United States)

    Gubkin, A. F.; Proskurina, E. P.; Kousaka, Y.; Sherokalova, E. M.; Selezneva, N. V.; Miao, P.; Lee, S.; Zhang, J.; Ishikawa, Y.; Torii, S.; Kamiyama, T.; Campo, J.; Akimitsu, J.; Baranov, N. V.

    2016-01-01

    Neutron diffraction measurements of the Cr intercalated niobium diselenide Cr1/3NbSe2 together with magnetization measurements have revealed that this compound exhibits ferromagnetic ordering below TC = 96 K unlike a chiral helimagnetic order observed in the sulfide compound Cr1/3NbS2. As derived from neutron diffraction data, the Cr magnetic moments μCr = 2.83 ± 0.03 μB in Cr1/3NbSe2 are aligned within basal plane. The discrepancy in the magnetic states of Cr1/3NbS2 and Cr1/3NbSe2 is ascribed to the difference in the preferential site occupation of Cr ions in crystal lattices. In Cr1/3NbSe2, the Cr ions are predominantly distributed over 2b Wyckoff site, which determines a centrosymmetric character of the crystal structure unlike Cr1/3NbS2, where the Cr ions are mainly located in 2c position and the crystal structure is non-centrosymmetric.

  10. Reconnection experiments including 3D magnetic nulls

    Science.gov (United States)

    Le, A.; Egedal, J.; Vrublevskis, A.

    2010-11-01

    A rich collection of magnetic reconnection scenarios is possible in three dimensions depending on the topological and geometric structure of the magnetic field [1]. In recent experiments at the Versatile Toroidal Facility (VTF) three-dimensional effects were essential even in nearly axisymmetric plasmas with a non-vanishing toroidal field [2]. To explore reconnection in 3D geometries including magnetic null points, a new adjustable set of coils will be installed in the vacuum chamber of VTF. The range of vacuum magnetic field topologies attainable in VTF will be explored numerically. Plasma reconnection experiments will be run in these configurations, and measurements will be presented if available. [4pt] [1] CE Parnell, et al., (2009) ``Three-Dimensional Magnetic Reconnection, in Magnetic Coupling between the Interior and the Atmosphere of the Sun,'' eds. S.S. Hasan and R.J. Rutten, Springer-Verlag, Heidelberg, Berlin. [0ex] [2] Katz, N. et al., (2010) Phys. Rev. Lett. 104, 255004.

  11. Magnetic Levitation Experiments with the Electrodynamic Wheel

    Science.gov (United States)

    Cordrey, Vincent; Gutarra-Leon, Angel; Gaul, Nathan; Majewski, Walerian

    Our experiments explored inductive magnetic levitation using circular Halbach arrays with the strong variable magnetic field on the outer rim of the ring. Such a system is usually called an Electrodynamic Wheel (EDW). Rotating this wheel around a horizontal axis above a flat conducting surface should induce eddy currents in said surface through the variable magnetic flux. The eddy currents produce, in turn, their own magnetic fields which interact with the magnets of the EDW. We constructed two Electrodynamic Wheels with different diameters and demonstrated that the magnetic interactions produce both lift and drag forces on the EDW which can be used for levitation and propulsion of the EDW. The focus of our experiments is the direct measurement of lift and drag forces to compare with theoretical models using wheels of two different radii. Supported by Grants from the Virginia Academy of Science, Society of Physics Students, Virginia Community College System, and the NVCC Educational Foundation.

  12. Experiments on a modular magnetic refrigeration device

    DEFF Research Database (Denmark)

    Engelbrecht, Kurt; Jensen, Jesper Buch; Bahl, Christian

    2012-01-01

    of different experiments. The test device is of the reciprocating type, and the magnetic field source is provided by a permanent Halbach magnet assembly with an average flux density of 1.03 Tesla. This work presents experimental results for flat plate regenerators made of gadolinium and sintered compounds...

  13. X-ray powder diffraction camera for high-field experiments

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, K; Mitsui, Y; Takahashi, K; Watanabe, K [High Field Laboratory for Superconducting Materials, Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)], E-mail: kkoyama@imr.tohoku.ac.jp

    2009-03-01

    We have designed a high-field X-ray diffraction (HF-XRD) camera which will be inserted into an experimental room temperature bore (100 mm) of a conventional solenoid-type cryocooled superconducting magnet (10T-CSM). Using the prototype camera that is same size of the HF-XRD camera, a XRD pattern of Si is taken at room temperature in a zero magnetic field. From the obtained results, the expected ability of the designed HF-XRD camera is presented.

  14. Neutron diffraction study of the magnetic structure of HoCu 2

    Science.gov (United States)

    Smetana, Z.; Šíma, V.; Lebech, B.

    1986-05-01

    Neutron diffraction measurements show that in the temperature range from 7.4 to TN=10.4 K the magnetic structure of HoCu 2 is a commensurably modulated a-axis collinear structure with a wave vector q1=1/3 a∗. Below 7.4 K an additional structure component develops and the low temperature magnetic structure of HoCu 2 is found to be an incommensurably modulated non-collinear structure characterized by wave vectors q 1=/13; a∗, q2= qcc∗ and 2 q2, where a∗ and c∗ are reciprocal lattice vectors of the orthorhombic structure and qc=0.300±0.005. The corresponding moment components μ- q1, μq2 and μ2q2 lie along the a, b and b directions of the orthorhombic crystal lattice, respectively.

  15. Reconnection experiments with 3D magnetic nulls

    Science.gov (United States)

    Vrublevskis, A.; Egedal, J.; Le, A.; Montag, P.

    2011-10-01

    Three-dimensional effects have been crucial in explaining experiments at the Versatile Toroidal Facility (VTF) even in nominal axisymmetric plasmas with a non-vanishing toroidal field. In general, depending on the topological and geometric structure of the magnetic field, a rich collection of magnetic reconnection scenarios is possible in three dimensions. The new adjustable set of coils in VTF allows exploring reconnection in 2D and 3D geometries including configurations with magnetic null points. We present results of a numerical and experimental investigation of magnetic field topologies attainable in VTF. This work was supported by NSF CAREER Award 0844620.

  16. Neutron diffraction studies of magnetic ordering in Ni-doped LaCoO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Rajeevan, N.E. [Department of Physics, Z.G. College, Calicut 673014, Kerala (India); Kumar, Vinod; Kumar, Rajesh [Department of Physics, National Institute of Technology, Hamirpur 177005, Himachal Pradesh (India); Kumar, Ravi [Beant College of Engineering and Technology, Gurudaspur 143521, Punjab (India); Kaushik, S.D. [UGC-DAE CSR Mumbai Centre, R-5 Shed, BARC, Mumbai 400085, Maharashtra (India)

    2015-11-01

    Research in rare earth cobaltite has recently been intensified due to its fascinating magnetic properties. LaCoO{sub 3}, an important cobaltite, exhibits two prominent susceptibility features at ~90 K and 500 K in low field measurement. The magnetic behavior below 100 K is predominantly antiferromagnetic (AFM), but absence of pure AFM ordering and emergence of ferromagnetic coupling on further decreasing temperature made situation more intricate. The present work of studying the effect of Ni substitution at Co site in polycrystalline LaCo{sub 1−x}Ni{sub x}O{sub 3} (0≤x≤0.3) is motivated by the interesting changes in magnetic and electronic properties. For lucid understanding, temperature dependent neutron diffraction (ND) study was carried out. ND patterns fitted with rhombohedral structure in perovskite form with R-3c space group, elucidated information on phase purity. Further temperature dependent cell parameter, Co–O bond-length and Co–O–Co bond angle were calculated for the series of Ni doped LaCoO{sub 3}. The results are explained in terms of decrease in the crystal field energy which led to the transition of cobalt from low Spin (LS) state to intermediate spin state (IS). - Highlights: • Temperature dependent neutron diffraction (ND) on Ni doped LaCoO{sub 3} are studied. • Microscopic parameters (cell, bond length, bond angle etc.) are determined by ND. • Increase in Co–O bond length and decrease in Co–O–Co bond angle on Ni substitution. • Ionic radii of Co{sup +3} in IS state (0.56 Å) is larger than in LS state (0.54 Å). • Lattice expansion induced increase in Co–O length stabilizes Co{sup +3} in magnetic state.

  17. Development of low temperature and high magnetic field X-ray diffraction facility

    Energy Technology Data Exchange (ETDEWEB)

    Shahee, Aga; Sharma, Shivani; Singh, K.; Lalla, N. P., E-mail: nplallaiuc82@gmail.com; Chaddah, P. [UGC-DAE Consortium for Scientific Research, University campus, Khandwa Road, Indore-452001 (India)

    2015-06-24

    The current progress of materials science regarding multifunctional materials (MFM) has put forward the challenges to understand the microscopic origin of their properties. Most of such MFMs have magneto-elastic correlations. To investigate the underlying mechanism it is therefore essential to investigate the structural properties in the presence of magnetic field. Keeping this in view low temperature and high magnetic field (LTHM) powder x-ray diffraction (XRD), a unique state-of-art facility in the country has been developed at CSR Indore. This setup works on symmetric Bragg Brentano geometry using a parallel incident x-ray beam from a rotating anode source working at 17 kW. Using this one can do structural studies at non-ambient conditions i.e. at low- temperatures (2-300 K) and high magnetic field (+8 to −8 T). The available scattering angle ranges from 5° to 115° 2θ with a resolution better than 0.1°. The proper functioning of the setup has been checked using Si sample. The effect of magnetic field on the structural properties has been demonstrated on Pr{sub 0.5}Sr{sub 0.5}MnO{sub 3} sample. Clear effect of field induced phase transition has been observed. Moreover, the effect of zero field cooled and field cooled conditions is also observed.

  18. Orientation Determination in Single Particle X-ray Coherent Diffraction Imaging Experiments

    CERN Document Server

    Yefanov, O M

    2013-01-01

    Single particle diffraction imaging experiments at free-electron lasers (FEL) have a great potential for structure determination of reproducible biological specimens that can not be crystallized. One of the challenges in processing the data from such an experiment is to determine correct orientation of each diffraction pattern from samples randomly injected in the FEL beam. We propose an algorithm (see also O. Yefanov et al., Photon Science - HASYLAB Annual Report 2010) that can solve this problem and can be applied to samples from tens of nanometers to microns in size, measured with sub-nanometer resolution in the presence of noise. This is achieved by the simultaneous analysis of a large number of diffraction patterns corresponding to different orientations of the particles. The algorithms efficiency is demonstrated for two biological samples, an artificial protein structure without any symmetry and a virus with icosahedral symmetry. Both structures are few tens of nanometers in size and consist of more tha...

  19. Verification of the weak equivalence principle with Laue diffracting neutrons: Test experiment

    Science.gov (United States)

    Vezhlev, E. O.; Voronin, V. V.; Kuznetsov, I. A.; Semenikhin, S. Yu.; Fedorov, V. V.

    2013-07-01

    We propose a novel experiment to test the weak equivalence principle (WEP) for the Laue diffracting neutron. Our experiment is based on an essential magnification of an external affect on neutron diffracting by Laue for the Bragg angles close to the right one in couple with additional enhancement factor which exists due to the delay of the Laue diffracting neutron at such Bragg angles. This enhancement phenomena is proposed to be utilized for measuring the force which deviates from zero if WEP is violated. The accuracy of measuring inertial to gravitational neutron masses ratio for the introduced setup can reach ˜10-5, which is more than one order superior to the best present-day result.

  20. Experiments with Coler magnetic current apparatus

    Science.gov (United States)

    Ludwig, T.

    Experiments with a replica of the famous Coler "Magnetstromapparat" (magnetic current apparatus) were conducted. The replica was built at the same institute at the Technical University of Berlin where the original was tested by Prof. Kloss in 1925. The details of the setup will be presented in this paper. The investigation of the Coler device was done with modern methods. The output was measured with a digital multi meter (DMM) and a digital storage oscilloscope (DSO). The results of the measurements will be presented. Did Coler convert vacuum fluctuations via magnetic, electric and acoustic resonance into electricity? There is a strong connection between magnetism and quantum field radiation energy. The magnetic moment of the electron is in part an energy exchange with the radiation field. The energy output of the Coler apparatus is measured. Furthermore the dynamics of the ferromagnetic magnets that Coler reported as the working principle of his device was investigated with magnetic force microscopy (MFM) and the spectroscopy mode of an atomic force microscope (AFM). The magnetic and acoustic resonance was investigated with magnetic force microscopy (MFM). The connection between ZPE and magnetism will be discussed as well as the perspective of using magnetic systems as a means to convert vacuum fluctuations into usable electricity.

  1. EuTiO3 magnetic structure studied by neutron powder diffraction and resonant x-ray scattering

    Science.gov (United States)

    Scagnoli, Valerio; Allieta, Mattia; Walker, Helen; Scavini, Marco; Katsufuji, Takuro; Sagarna, Leyre; Zaharko, Oksana; Mazzoli, Claudio

    2012-09-01

    We combine neutron powder diffraction and x-ray single-crystal magnetic diffraction at the Eu L2 edge to scrutinize the magnetic motif of the Eu ions in magnetoelectric EuTiO3. Our measurements are consistent with an antiferromagnetic G-type pattern with the Eu magnetic moments ordering along the a,b-plane diagonal. Recent reports of a novel transition at 2.75 K with a flop of magnetic moments upon poling the sample in an electric field cannot be confirmed for a nonpoled sample. Our neutron diffraction data do not show any significant change of the structure below the Néel temperature. Magnetoelastic coupling, if present, is therefore expected to be negligible.

  2. Magnetic flux array for spontaneous magnetic reconnection experiments.

    Science.gov (United States)

    Kesich, A; Bonde, J; Egedal, J; Fox, W; Goodwin, R; Katz, N; Le, A

    2008-06-01

    Experimental investigation of reconnection in magnetized plasmas relies on accurate characterization of the evolving magnetic fields. In experimental configurations where the plasma dynamics are reproducible, magnetic data can be collected in multiple discharges and combined to provide spatially resolved profiles of the plasma dynamics. However, in experiments on spontaneous magnetic reconnection recently undertaken at the Versatile Toroidal Facility at MIT, the reconnection process is not reproducible and all information on the plasma must be collected in a single discharge. This paper describes a newly developed magnetic flux array which directly measures the toroidal component of the magnetic vector potential, A(phi). From the measured A(phi), the magnetic field geometry, current density, and reconnection rate are readily obtained, facilitating studies of the three-dimensional dynamics of spontaneous magnetic reconnection. The novel design of the probe array allows for accurate characterization of profiles of A(phi) at multiple toroidal angles using a relatively small number of signal channels and with minimal disturbance of the plasma.

  3. ALICE Diffractive Detector Control System for RUN-II in the ALICE Experiment

    CERN Document Server

    INSPIRE-00522336; Martinez, M.I.; Monzon, I. Leon

    2016-01-01

    This paper describes general characteristics of the deployment and commissioned of the Detector Control System (DCS) AD0 for the second phase of the Large Hadron Collider (LHC). The AD0 detector is installed in the ALICE experiment to provide a better selection of diffractive events.

  4. Neutron diffraction studies of magnetic ordering in Ni-doped LaCoO3

    Science.gov (United States)

    Rajeevan, N. E.; Kumar, Vinod; Kumar, Rajesh; Kumar, Ravi; Kaushik, S. D.

    2015-11-01

    Research in rare earth cobaltite has recently been intensified due to its fascinating magnetic properties. LaCoO3, an important cobaltite, exhibits two prominent susceptibility features at ~90 K and 500 K in low field measurement. The magnetic behavior below 100 K is predominantly antiferromagnetic (AFM), but absence of pure AFM ordering and emergence of ferromagnetic coupling on further decreasing temperature made situation more intricate. The present work of studying the effect of Ni substitution at Co site in polycrystalline LaCo1-xNixO3 (0≤x≤0.3) is motivated by the interesting changes in magnetic and electronic properties. For lucid understanding, temperature dependent neutron diffraction (ND) study was carried out. ND patterns fitted with rhombohedral structure in perovskite form with R-3c space group, elucidated information on phase purity. Further temperature dependent cell parameter, Co-O bond-length and Co-O-Co bond angle were calculated for the series of Ni doped LaCoO3. The results are explained in terms of decrease in the crystal field energy which led to the transition of cobalt from low Spin (LS) state to intermediate spin state (IS).

  5. Neutron and X-ray single-crystal diffraction from protein microcrystals via magnetically oriented microcrystal arrays in gels.

    Science.gov (United States)

    Tsukui, Shu; Kimura, Fumiko; Kusaka, Katsuhiro; Baba, Seiki; Mizuno, Nobuhiro; Kimura, Tsunehisa

    2016-07-01

    Protein microcrystals magnetically aligned in D2O hydrogels were subjected to neutron diffraction measurements, and reflections were observed for the first time to a resolution of 3.4 Å from lysozyme microcrystals (∼10 × 10 × 50 µm). This result demonstrated the possibility that magnetically oriented microcrystals consolidated in D2O gels may provide a promising means to obtain single-crystal neutron diffraction from proteins that do not crystallize at the sizes required for neutron diffraction structure determination. In addition, lysozyme microcrystals aligned in H2O hydrogels allowed structure determination at a resolution of 1.76 Å at room temperature by X-ray diffraction. The use of gels has advantages since the microcrystals are measured under hydrated conditions.

  6. Teaching Representation Translations with Magnetic Field Experiments

    Science.gov (United States)

    Tillotson, Wilson Andrew; McCaskey, Timothy; Nasser, Luis

    2017-01-01

    We have developed a laboratory exercise designed to help students translate between different field representations. It starts with students qualitatively mapping field lines for various bar magnet configurations and continues with a Hall probe experiment in which students execute a series of scaffolded tasks, culminating in the prediction and measurement of the spatial variation of magnetic field components along a line near magnets. We describe the experimental tasks, various difficulties students have throughout, and ways this lab makes even their incorrect predictions better. We suggest that developing lab activities of this nature brings a new dimension to the ways students learn and interact with field concepts.

  7. Purification, crystallization and preliminary X-ray diffraction experiment of nattokinase from Bacillus subtilis natto.

    Science.gov (United States)

    Yanagisawa, Yasuhide; Chatake, Toshiyuki; Chiba-Kamoshida, Kaori; Naito, Sawa; Ohsugi, Tadanori; Sumi, Hiroyuki; Yasuda, Ichiro; Morimoto, Yukio

    2010-12-01

    Nattokinase is a single polypeptide chain composed of 275 amino acids (molecular weight 27,724) which displays strong fibrinolytic activity. Moreover, it can activate other fibrinolytic enzymes such as pro-urokinase and tissue plasminogen activator. In the present study, native nattokinase from Bacillus subtilis natto was purified using gel-filtration chromatography and crystallized to give needle-like crystals which could be used for X-ray diffraction experiments. The crystals belonged to space group C2, with unit-cell parameters a=74.3, b=49.9, c=56.3 Å, β=95.2°. Diffraction images were processed to a resolution of 1.74 Å with an Rmerge of 5.2% (15.3% in the highest resolution shell) and a completeness of 69.8% (30.0% in the highest resolution shell). This study reports the first X-ray diffraction analysis of nattokinase.

  8. Stress-induced martensite variant reorientation in magnetic shape memory Ni Mn Ga single crystal studied by neutron diffraction

    Science.gov (United States)

    Molnar, P.; Sittner, P.; Lukas, P.; Hannula, S.-P.; Heczko, O.

    2008-06-01

    Stress-induced martensite variant reorientation in magnetic shape memory Ni-Mn-Ga single crystal was studied in situ by the neutron diffraction technique. Principles of determination of individual tetragonal martensitic variants in shape memory alloys are explained. Using neutron diffraction we show that the macroscopic strain originates solely from the martensite structure reorientation or variant redistribution. Neutron diffraction also reveals that the reorientation of martensite is not fully completed even at a stress value of 25 MPa, which is about 20 times larger than the mean stress needed for reorientation. Only one twinning system is active during the reorientation process.

  9. Controlled molecules for X-ray diffraction experiments at free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Stern, Stephan

    2013-12-15

    X-ray diffractive imaging is at the very heart of materials science and has been utilized for decades to solve unknown molecular structures. Nowadays, it serves as the key method of structural biology to solve molecular structures of large biological molecules comprising several thousand or even millions of atoms. However, X-ray diffraction from isolated molecules is very weak. Therefore, the regular and periodic arrangement of a huge number of identical copies of a certain molecule of interest within a crystal lattice has been a necessary condition in order to exploit Bragg diffraction of X-rays. This results in a huge increase in scattered signal and a strongly improved signal-to-noise ratio compared to diffraction from non-crystalline samples. The major bottleneck of structural biology is that many of biologically interesting molecules refuse to form crystals of sufficient size to be used at synchrotron X-ray lightsources. However, novel X-ray free-electron lasers (XFELs), which became operational very recently, promise to address this issue. X-ray pulses provided by XFELs are many orders of magnitude more intense than X-ray pulses from a synchrotron source and at the same time as short as only several tens of femtoseconds. Combined with wavelengths in the nm-pm range, XFELs are well-suited to study ultrafast atomic and molecular dynamics. Additionally, the ultrashort pulses can be utilized to circumvent the damage threshold which set a limit to the incident intensity in X-ray diffraction experiments before. At XFELs, though eventually destroying the investigated sample, no significant sample deterioration happens on the ultrashort timescale of the XFEL pulse and the measured diffraction pattern is due to an (almost) unharmed sample. In the framework of this thesis, the approach of utilizing the highly intense XFEL pulses for X-ray diffraction of weakly-scattering non-crystalline samples was taken to the limit of small isolated molecules. X-ray diffraction was

  10. Measurement of the longitudinal proton structure function in diffraction at the H1 experiment and prospects for diffraction at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Salek, David

    2011-05-15

    A measurement of the longitudinal diffractive structure function F{sub L}{sup D} using the H1 detector at HERA is presented. The structure function is extracted from first measurements of the diffractive cross section ep{yields}eXY at centre of mass energies {radical}(s) of 225 and 252 GeV at high values of inelasticity y, together with a new measurement at {radical}(s) of 319 GeV, using data taken in 2006 and 2007. Previous H1 data at {radical}(s) of 301 GeV complete the kinematic coverage needed to extract F{sub L}{sup D} in the range of photon virtualities 2.5diffractive parton densities extracted in NLO QCD fits to previous diffractive DIS data and to a model which additionally includes a higher twist contribution derived from a colour dipole approach. The photoabsorption ratio for diffraction RD is extracted for Q{sup 2}>7 GeV{sup 2} and compared to the analogous quantity for inclusive DIS. (orig.)

  11. Magnetic field homogeneity for neutron EDM experiment

    Science.gov (United States)

    Anderson, Melissa

    2016-09-01

    The neutron electric dipole moment (nEDM) is an observable which, if non-zero, would violate time-reversal symmetry, and thereby charge-parity symmetry of nature. New sources of CP violation beyond those found in the standard model of particle physics are already tightly constrained by nEDM measurements. Our future nEDM experiment seeks to improve the precision on the nEDM by a factor of 30, using a new ultracold neutron (UCN) source that is being constructed at TRIUMF. Systematic errors in the nEDM experiment are driven by magnetic field inhomogeneity and instability. The goal field inhomogeneity averaged over the experimental measurement cell (order of 1 m) is 1 nT/m, at a total magnetic field of 1 microTesla. This equates to roughly 10-3 homogeneity. A particularly challenging aspect of the design problem is that nearby magnetic materials will also affect the magnetic inhomogeneity, and this must be taken into account in completing the design. This poster will present the design methodology and status of the main coil for the experiment where we use FEA software (COMSOL) to simulate and analyze the magnetic field. Natural Sciences and Engineering Research Council.

  12. A magnet system for HEP experiments

    CERN Document Server

    Gaddi, A

    2012-01-01

    This chapter describes the sequence of steps that lead to the design of a magnet system for modern HEP detectors. We start looking to the main types of magnets used in HEP experiments, along with some basic formulae to set the main parameters, such as ampere-turns, impedance and stored energy. A section is dedicated to the description of the iron yoke, with emphasis on magnet-detector integration and assembly, steel characteristics, stray field issues and alternative design. In the second part of the chapter we start looking at a brief history of superconducting magnets and a comparison between warm and superconducting ones. Following that, we describe the commonly used superconducting cables, the conductor design and technology and the winding techniques. A section of the chapter is dedicated to the cryogenic design, vacuum insulation and other ancillary systems. We also describe the power circuit, with the power supply unit, the current leads, the current measurement devices and other instruments and safety...

  13. Forces between permanent magnets: experiments and model

    Science.gov (United States)

    González, Manuel I.

    2017-03-01

    This work describes a very simple, low-cost experimental setup designed for measuring the force between permanent magnets. The experiment consists of placing one of the magnets on a balance, attaching the other magnet to a vertical height gauge, aligning carefully both magnets and measuring the load on the balance as a function of the gauge reading. A theoretical model is proposed to compute the force, assuming uniform magnetisation and based on laws and techniques accessible to undergraduate students. A comparison between the model and the experimental results is made, and good agreement is found at all distances investigated. In particular, it is also found that the force behaves as r -4 at large distances, as expected.

  14. Magnetic structure of Pr6Fe13Ge studied by M(o)ssbauer effect and neutron diffraction

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Magnetic structure of Pr6Fe13Ge at room temperature has been investigated by magnetic measurement, M ssbauer effect and neutron diffraction. Magnetic atoms are closely packed up and down the mirror planes at z=0 and 1/2 and separated by the non-magnetic atoms located on the planes at z=1/4 and 3/4, which constructs an M/NM/M sandwich structure (M: magnetic, NM: non-magnetic). The intralayer magnetic moments couple ferromagnetically and are out of ab plane at a small angle so as to form a component along c-axis. The interlayer coupling is antiferromagnetic for the ab component while ferromagnetic for the c component.

  15. Magnetohydrodynamic experiments on cosmic magnetic fields

    CERN Document Server

    Stefani, Frank; Gerbeth, Gunter

    2008-01-01

    It is widely known that cosmic magnetic fields, including the fields of planets, stars, and galaxies, are produced by the hydromagnetic dynamo effect in moving electrically conducting fluids. It is less well known that cosmic magnetic fields play also an active role in cosmic structure formation by enabling outward transport of angular momentum in accretion disks via the magnetorotational instability (MRI). Considerable theoretical and computational progress has been made in understanding both processes. In addition to this, the last ten years have seen tremendous efforts in studying both effects in liquid metal experiments. In 1999, magnetic field self-excitation was observed in the large scale liquid sodium facilities in Riga and Karlsruhe. Recently, self-excitation was also obtained in the French "von Karman sodium" (VKS) experiment. An MRI-like mode was found on the background of a turbulent spherical Couette flow at the University of Maryland. Evidence for MRI as the first instability of an hydrodynamica...

  16. Spin and diffractive physics with a fixed-target experiment at the LHC (AFTER-LHC)

    Energy Technology Data Exchange (ETDEWEB)

    Lorce, C.; Chambert, V.; Didelez, J. P.; Genolini, B.; Hadjidakis, C.; Lansberg, J. P.; Rosier, P. [IPNO, Universite Paris-Sud, CNRS/IN2P3, F-91406, Orsay (France); Anselmino, M.; Arnaldi, R.; Scomparin, E. [INFN Sez. Torino, Via P. Giuria 1,1-10125, Torino (Italy); Brodsky, S. J. [SLAC National Accelerator Laboratory, Stanford U, Stanford, CA 94309, (United States); Ferreiro, E. G. [Departamento de Fisica de Particulas, Univ. de Santiago de C, 15782 Santiago de C (Spain); Fleuret, F. [Laboratoire Leprince Ringuet, Ecole Polytechnique, CNRS/IN2P3, 91128 Palaiseau (France); Rakotozafindrabe, A. [IRFU/SPhN, CFA Society, 91191 Gifsur-Yvette Cedex (France); Schienbein, I. [LPSC, Universite Joseph Fourier, CNRS/IN2P3/INPG, F-38026 Grenoble (France); Uggerhoj, U. I. [Department of Physics and Astronomy, University of Aarhus (Denmark)

    2013-04-15

    We report on the spin and diffractive physics at a future multi-purpose f xed-target experiment with proton and lead LHC beams extracted by a bent crystal. The LHC multi-TeV beams allow for the most energetic f xed-target experiments ever performed, opening new domains of particle and nuclear physics and complementing that of collider physics, in particular that of RHIC and the EIC projects. The luminosity achievable with AFTER using typical targets would surpass that of RHIC by more than 3 orders of magnitude. The f xed-target mode has the advantage to allow for measurements of single-spin asymmetries with polarized target as well as of single-diffractive processes in the target region.

  17. Neutron diffraction study of MnNiGa{sub 2}—Structural and magnetic behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J. L., E-mail: jianli@uow.edu.au [Institute for Superconductivity and Electronic Materials, University of Wollongong, Wollongong, NSW 2522 (Australia); Bragg Institute, ANSTO, Lucas Heights, NSW 2234 (Australia); School of Physical, Environmental and Mathematical Sciences, The University of New South Wales, Canberra, ACT 2600 (Australia); Ma, L.; Wu, G. H. [Institute of Physics, Chinese Academy of Science, Beijing 100190 (China); Hofmann, M. [FRM-II, Technische Universität München, 85747 Garching (Germany); Avdeev, M.; Kennedy, S. J. [Bragg Institute, ANSTO, Lucas Heights, NSW 2234 (Australia); Campbell, S. J. [School of Physical, Environmental and Mathematical Sciences, The University of New South Wales, Canberra, ACT 2600 (Australia); Md Din, M. F.; Dou, S. X. [Institute for Superconductivity and Electronic Materials, University of Wollongong, Wollongong, NSW 2522 (Australia); Hoelzel, M. [FRM-II, Technische Universität München, 85747 Garching (Germany); Fachbereich Materialwissenschaften, Technische Universität Darmstadt, 64287 Darmstadt (Germany)

    2014-05-07

    MnNiGa{sub 2} crystallizes in the L21 (Heusler) structure and has a ferromagnetic ordering temperature T{sub C} ∼ 192 K. Rietveld refinement of the neutron diffraction patterns indicates that the Ga atoms occupy the equivalent 8c position, while Mn and Ni share the 4a (0, 0, 0) and 4b (0.5, 0.5, 0.5) sites with a mixed occupancy of Mn and Ni atoms. It is found that that ∼83% of Mn and ∼17% Ni are located at the 4a site while ∼83% of Ni and ∼17% Mn occupy the 4b site. There is no evidence of a magneto-volume effect around T{sub C}. In agreement with this finding, our detailed critical exponent analyses of isothermal magnetization curves and the related Arrott plots confirm that the magnetic phase transition at T{sub C} is second order.

  18. Teaching Representation Translations with Magnetic Field Experiments

    Science.gov (United States)

    Tillotson, Wilson Andrew; McCaskey, Timothy; Nasser, Luis

    2017-01-01

    We have developed a laboratory exercise designed to help students translate between different field representations. It starts with students qualitatively mapping field lines for various bar magnet configurations and continues with a Hall probe experiment in which students execute a series of scaffolded tasks, culminating in the prediction and…

  19. Teaching Representation Translations with Magnetic Field Experiments

    Science.gov (United States)

    Tillotson, Wilson Andrew; McCaskey, Timothy; Nasser, Luis

    2017-01-01

    We have developed a laboratory exercise designed to help students translate between different field representations. It starts with students qualitatively mapping field lines for various bar magnet configurations and continues with a Hall probe experiment in which students execute a series of scaffolded tasks, culminating in the prediction and…

  20. Ultrahigh vacuum/high pressure chamber for surface x-ray diffraction experiments

    Science.gov (United States)

    Bernard, P.; Peters, K.; Alvarez, J.; Ferrer, S.

    1999-02-01

    We describe an ultrahigh vacuum chamber that can be internally pressurized to several bars and that is designed to perform surface x-ray diffraction experiments on solid-gas interfaces. The chamber has a cylindrical beryllium window that serves as the entrance and exit for the x rays. The sample surface can be ion bombarded with an ancillary ion gun and annealed to 1200 K.

  1. Influence of Al on the magnetic properties of TmCo{sub 4}Al compound, a magnetic and neutron diffraction study

    Energy Technology Data Exchange (ETDEWEB)

    Laslo, A. [CNRS, Inst. Néel, F-38042 Grenoble (France); Univ. Grenoble Alpes, Inst. Néel, F-38042 Grenoble (France); Babes-Bolyai University, Faculty of Physics, 400084 Cluj-Napoca (Romania); Pop, V. [Babes-Bolyai University, Faculty of Physics, 400084 Cluj-Napoca (Romania); Isnard, O. [CNRS, Inst. Néel, F-38042 Grenoble (France); Univ. Grenoble Alpes, Inst. Néel, F-38042 Grenoble (France)

    2015-03-25

    Highlights: • The existence of a compensation temperature is found for TmCo{sub 4}Al. • The crystal structure and its thermal evolution are analysed by X-ray and neutron diffraction. • The ferrimagnetic magnetic structure of TmCo{sub 4}Al is established. • Magnetic properties are determined. • Significant coercivity is reported for TmCo{sub 4}Al. - Abstract: The structural and magnetic properties of the TmCo{sub 4}Al compound are presented as deduced from magnetic measurements, X-ray and neutron powder diffraction. The crystal structure is obtained in the light of Rietveld refinement of the neutron powder diffraction pattern. The symmetry of the CaCu{sub 5} structure is preserved and the Al atom is found to substitute the Co one exclusively on the 3g atomic position. Thermal expansion of the crystal lattice is reported, the temperature variation occurring mostly along the basal hexagonal plane. This compound exhibits a ferrimagnetic structure, the Tm and Co magnetic moments being coupled antiparallel. An ordering temperature of 511 K is found. The thermal dependence of the Tm magnetic moment is obtained down to 4 K. A compensation of the two sublattice magnetization is found at 75 K, a feature induced by the Al for Co substitution and not observed in the corresponding TmCo{sub 5} compound. Magnetization curves reveal large coercivity values at low temperature such as 2.48 T at 2 K.

  2. Investigation of the magnetic properties in thin Fe50Pt50-xRhx films by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Fenske, J.; Lott, D.; Schreyer, A. [GKSS Research Centre (Germany); Mankey, G.J. [University of Alabama, MINT Center (United States); Schmidt, W.; Schmalzl, K. [Juelich Research Centre (Germany); Tartakowskaya, E. [Institute for Magnetism, National Accademy of Science (United States)

    2009-07-01

    FePt-based alloys are typically the material of choice for magnetic information storage media. The high magnetic moment of Fe gives a large magnetization and the large atomic number of Pt results in a high magnetic anisotropy. This combination enables the written bits to be smaller than ever before, since magnetic grains with a high magnetic anisotropy are more thermally stable. One way to control the magnetic properties in these materials is through the introduction of a third element into the crystal matrix, e.g. Rh. When Rh is added to replace Pt in the equiatomic alloy, new magnetic phases emerge. Bulk samples of Fe{sub 50}Pt{sub 40}Rh{sub 10} for example, studied by magnetization measurements refer to an antiferromagnetic (AF)/ferromagnetic (FM) phase transition at about 150 K when heated. Additional magnetostriction measurements indicate that the phase transition could also be induced by applying a magnetic field. Here we present results on several Fe{sub 50}Pt{sub 50-x}Rh{sub x} films. These films were examined by neutron diffraction in dependence of temperature and magnetic field. The observed magnetic behaviours differ significant from the behaviour of the bulk system.

  3. Magnetic Monopole Search with the SLIM Experiment

    CERN Document Server

    Medinaceli, E

    2008-01-01

    The SLIM experiment was an array of 427 m^2 of nuclear track detectors, exposed at a high altitude laboratory (Chacaltaya, Bolivia, 5230 m a.s.l.), for ~4.22 years. SLIM was sensitive to downgoing intermediate mass magnetic monopoles with masses in the range 10^5 to 10^12 GeV. The analysis of the full detector gives a flux upper limit of 1.3x10^{-15} 1/(cm^2*s*sr) (90% C.L.) for downgoing fast intermediate magnetic monopoles.

  4. Magnetic processes in astrophysics theory, simulations, experiments

    CERN Document Server

    Rüdiger, Günther; Hollerbach, Rainer

    2013-01-01

    In this work the authors draw upon their expertise in geophysical and astrophysical MHD to explore the motion of electrically conducting fluids, the so-called dynamo effect, and describe the similarities and differences between different magnetized objects. They also explain why magnetic fields are crucial to the formation of the stars, and discuss promising experiments currently being designed to investigate some of the relevant physics in the laboratory. This interdisciplinary approach will appeal to a wide audience in physics, astrophysics and geophysics. This second edition covers such add

  5. A Neutron Diffraction Study of the Nuclear and Magnetic Structure of MnNb2O6

    DEFF Research Database (Denmark)

    Nielsen, Oliver Vindex; Lebech, Bente; Krebs Larsen, F.;

    1976-01-01

    A neutron diffraction study was made of the nuclear and the magnetic structure of MnNb2O6 single crystals. The thirteen nuclear parameters (space group Pbcn) were determined from 304 reflections at room temperature. The antiferromagnetic structure (Neel temperature=4.4K), determined at 1.2K, is a...

  6. A novel setup for time-resolved X-ray diffraction on gas gun experiments

    Science.gov (United States)

    Zucchini, Frédéric; Chauvin, Camille; Loyen, Arnaud; Combes, Philippe; Petit, Jacques; Bland, Simon

    2017-01-01

    Polymorphic phase transitions in metals have been investigated for a long time under dynamic loadings through usual dynamic compression diagnostics such as velocity and temperature measurements. Such measurements were valuable for revealing the key role of kinetic effects in most phase transition mechanisms. However, the information extracted was mostly macroscopic. Obtaining direct insight about the crystallographic structure under dynamic loadings is critical for understanding mechanisms governing shock-induced structural changes. For example, in order to evidence a mixture phase or to determine the time scale of a transition, structural information may be extremely valuable. Over the last 20 years a significant number of X-ray diffraction experiments were carried under dynamic loading, either using laboratory X-ray sources or synchrotron radiation. We are developing a novel experimental setup based on a compact High Pulsed Power generator capable of producing intense X radiation through an X-pinch X-ray source. This source is specifically designed for time-resolved X-ray diffraction in Bragg geometry on gas gun experiments. Promising preliminary diffraction data obtained under static conditions are presented.

  7. Magnetic Flux Compression Experiments Using Plasma Armatures

    Science.gov (United States)

    Turner, M. W.; Hawk, C. W.; Litchford, R. J.

    2003-01-01

    Magnetic flux compression reaction chambers offer considerable promise for controlling the plasma flow associated with various micronuclear/chemical pulse propulsion and power schemes, primarily because they avoid thermalization with wall structures and permit multicycle operation modes. The major physical effects of concern are the diffusion of magnetic flux into the rapidly expanding plasma cloud and the development of Rayleigh-Taylor instabilities at the plasma surface, both of which can severely degrade reactor efficiency and lead to plasma-wall impact. A physical parameter of critical importance to these underlying magnetohydrodynamic (MHD) processes is the magnetic Reynolds number (R(sub m), the value of which depends upon the product of plasma electrical conductivity and velocity. Efficient flux compression requires R(sub m) less than 1, and a thorough understanding of MHD phenomena at high magnetic Reynolds numbers is essential to the reliable design and operation of practical reactors. As a means of improving this understanding, a simplified laboratory experiment has been constructed in which the plasma jet ejected from an ablative pulse plasma gun is used to investigate plasma armature interaction with magnetic fields. As a prelude to intensive study, exploratory experiments were carried out to quantify the magnetic Reynolds number characteristics of the plasma jet source. Jet velocity was deduced from time-of-flight measurements using optical probes, and electrical conductivity was measured using an inductive probing technique. Using air at 27-inHg vacuum, measured velocities approached 4.5 km/s and measured conductivities were in the range of 30 to 40 kS/m.

  8. VINETA II: a linear magnetic reconnection experiment.

    Science.gov (United States)

    Bohlin, H; Von Stechow, A; Rahbarnia, K; Grulke, O; Klinger, T

    2014-02-01

    A linear experiment dedicated to the study of driven magnetic reconnection is presented. The new device (VINETA II) is suitable for investigating both collisional and near collisionless reconnection. Reconnection is achieved by externally driving magnetic field lines towards an X-point, inducing a current in the background plasma which consequently modifies the magnetic field topology. Owing to the open field line configuration of the experiment, the current is limited by the axial sheath boundary conditions. A plasma gun is used as an additional electron source in order to counterbalance the charge separation effects and supply the required current. Two drive methods are used in the device. First, an oscillating current through two parallel conductors drive the reconnection. Second, a stationary X-point topology is formed by the parallel conductors, and the drive is achieved by an oscillating current through a third conductor. In the first setup, the magnetic field of the axial plasma current dominates the field topology near the X-point throughout most of the drive. The second setup allows for the amplitude of the plasma current as well as the motion of the flux to be set independently of the X-point topology of the parallel conductors.

  9. Event Classification and Estimation of Low Mass Diffraction at the TOTEM Experiment at the LHC

    CERN Document Server

    Welti, J

    The TOTEM experiment is a forward physics experiment at the Large Hadron Collider (LHC) at CERN. The goal of the experiment is to study the structure of the proton and proton interactions at high energies. This includes a precise measurement of the total proton-proton cross section and the measurement of the cross sections for individual processes like elastic, non-diffractive minimum bias and single and double diffractive. The experiment comprises three different types of detectors: Roman Pot silicon detectors for detecting protons scattered by very small angles (few micro radians) and T1 and T2 forward tracking telescopes for detecting charged particles from inelastic proton-proton scattering. Each detector has a digital readout. The detectors for the T2 forward tracking telescope consist of three planes of gas electron multipliers. The radial coordinate is provided by the strip readout and the azimuthal coordinate and trigger are provided by the pad readout. Due to cross-talk and electronics noise, it is p...

  10. Lattice thermal expansion and anisotropic displacements in -sulfur from diffraction experiments and first-principles theory.

    Science.gov (United States)

    George, Janine; Deringer, Volker L; Wang, Ai; Müller, Paul; Englert, Ulli; Dronskowski, Richard

    2016-12-21

    Thermal properties of solid-state materials are a fundamental topic of study with important practical implications. For example, anisotropic displacement parameters (ADPs) are routinely used in physics, chemistry, and crystallography to quantify the thermal motion of atoms in crystals. ADPs are commonly derived from diffraction experiments, but recent developments have also enabled their first-principles prediction using periodic density-functional theory (DFT). Here, we combine experiments and dispersion-corrected DFT to quantify lattice thermal expansion and ADPs in crystalline α-sulfur (S8), a prototypical elemental solid that is controlled by the interplay of covalent and van der Waals interactions. We begin by reporting on single-crystal and powder X-ray diffraction measurements that provide new and improved reference data from 10 K up to room temperature. We then use several popular dispersion-corrected DFT methods to predict vibrational and thermal properties of α-sulfur, including the anisotropic lattice thermal expansion. Hereafter, ADPs are derived in the commonly used harmonic approximation (in the computed zero-Kelvin structure) and also in the quasi-harmonic approximation (QHA) which takes the predicted lattice thermal expansion into account. At the PPBE+D3(BJ) level, the QHA leads to excellent agreement with experiments. Finally, more general implications of this study for theory and experiment are discussed.

  11. Magnetic Field Gradient Calibration as an Experiment to Illustrate Magnetic Resonance Imaging

    Science.gov (United States)

    Seedhouse, Steven J.; Hoffmann, Markus M.

    2008-01-01

    A nuclear magnetic resonance (NMR) spectroscopy experiment for the undergraduate physical chemistry laboratory is described that encompasses both qualitative and quantitative pedagogical goals. Qualitatively, the experiment illustrates how images are obtained in magnetic resonance imaging (MRI). Quantitatively, students experience the…

  12. Magnetic properties of PrX 2 compounds (X = Pt, Rh, Ru, Ir) studied by hyperfine specific heat, magnetization and neutron-diffraction measurements

    Science.gov (United States)

    Greidanus, F. J. A. M.; de Jongh, L. J.; Huiskamp, W. J.; Fischer, P.; Furrer, A.; Buschow, K. H. J.

    1983-04-01

    Magnetic ordering phenomena in rare-earth intermetallic compounds can be unravelled most advantageously in the case of simple crystallographic structure and when a combination of microscopic techniques is applied. Here we shall present the temperature and magnetic field dependence of the magnetic moment of the cubic PrX 2 compounds (X = Pt, Rh, Ru, Ir), as inferred from hyperfine specific-heat, magnetization and neutron-diffraction measurements. The results are compared with a mean-field calculation, taking crystalline electric field and bilinear (dipolar) exchange interactions into account. Adopting experimental values of the Lea, Leask and Wolf parameters x and W from inelastic neutron scattering results, we find satisfactory agreement between our magnetic data and the mean-field theory. An observed discrepancy of about 15% between the calculated and measured saturation values of the spontaneous magnetization can be explained by the presence of quadrupolar interactions.

  13. Magnetic phases in the Kagomé staircase compound Co3V2O8 studied using powder neutron diffraction

    Science.gov (United States)

    Wilson, N. R.; Petrenko, O. A.; Chapon, L. C.

    2007-03-01

    The low temperature properties of the Kagomé-type system Co3V2O8 have been studied by powder neutron diffraction both in zero field and in applied magnetic fields of up to 8T . Below 6K , the zero-field ground state is ferromagnetic with the magnetic moments aligned along the a axis. The size of the moment on one of the two Co sites, the so-called cross-tie site, is considerably reduced compared to the fully polarized state. The application of a magnetic field in this phase is found to rapidly enhance the cross-tie site magnetic moment, which reaches the expected value of ˜3μB by the maximum applied field of 8T . Different reorientation behaviors are found for the Co cross-tie and spine sites, suggesting a more pronounced easy-axis anisotropy for moments on the spine sites. Rietveld refinements reveal that a simple model, where the spins on both cross-tie and spine sites rotate in the ac plane in a magnetic field, reproduces the experimental diffraction patterns well. In addition, it is found that at higher temperatures and moderate magnetic fields, the incommensurate antiferromagnetic order, corresponding to a transverse sinusoidal modulation above 8K , is suppressed to be replaced by ferromagnetic order.

  14. Origin of (105) Reflection of X-Ray Diffraction and Quantitative Evaluation of Alignment Degree for Sintered Nd-Fe-B Magnets

    Institute of Scientific and Technical Information of China (English)

    HE Ye-Qing; ZHOU Shou-Zeng; ZHANG Zhen-Rong; HAN Bao-Shan

    2001-01-01

    A new method for quantitatively evaluating the alignment degree ofsintered Nd-FeB magnets by x-ray diffraction spectra has been proposed. It has been experimentally revealed that the strong (105) reflection existing in almost all x-ray diffraction spectra of sintered Nd-FeB magnets stems from the misalignment grains whose easy axes are at an angle of 15.5° with respect to the orientated direction of the magnet.

  15. Single crystal polarized neutron diffraction study of the magnetic structure of HoFeO3.

    Science.gov (United States)

    Chatterji, T; Stunault, A; Brown, P J

    2017-07-05

    Polarised neutron diffraction measurements have been made on HoFeO3 single crystals magnetised in both the [0 0 1] and [1 0 0] directions (Pbnm setting). The polarisation dependencies of Bragg reflection intensities were measured both with a high field of [Formula: see text] T parallel to [0 0 1] at [Formula: see text] K and with the lower field [Formula: see text] T parallel to [1 0 0] at [Formula: see text] K. A Fourier projection of magnetization induced parallel to [0 0 1], made using the hk0 reflections measured in 9 T, indicates that almost all of it is due to alignment of Ho moments. Further analysis of the asymmetries of general reflections in these data showed that although, at 70 K, 9 T applied parallel to [0 0 1] hardly perturbs the antiferromagnetic order of the Fe sublattices, it induces significant antiferromagnetic order of the Ho sublattices in the [Formula: see text] plane, with the antiferromagnetic components of moment having the same order of magnitude as the induced ferromagnetic ones. Strong intensity asymmetries measured in the low temperature [Formula: see text] structure with a lower field, 0.5 T [Formula: see text] [1 0 0] allowed the variation of the ordered components of the Ho and Fe moments to be followed. Their absolute orientations, in the [Formula: see text] domain stabilised by the field were determined relative to the distorted perovskite structure. This relationship fixes the sign of the Dzyalshinski-Moriya (D-M) interaction which leads to the weak ferromagnetism. Our results indicate that the combination of strong y-axis anisotropy of the Ho moments and Ho-Fe exchange interactions breaks the centrosymmetry of the structure and could lead to ferroelectric polarization.

  16. Magnetic Compression Experiment at General Fusion

    Science.gov (United States)

    Dunlea, Carl; Howard, Stephen; Epp, Kelly; Zawalski, Wade; Kim, Charlson; Fusion Team, General

    2016-10-01

    The magnetic compression experiment at General Fusion was designed as a repetitive non-destructive test to study plasma physics applicable to Magnetic Target Fusion compression. A spheromak compact torus (CT) is formed with a co-axial gun into a containment region with an hour-glass shaped inner flux conserver, and an insulating outer wall. The experiment has external coils to keep the CT off the outer wall (levitation) and then rapidly compress it inwards. Experiments used a variety of levitation/compression field profiles. The optimal configuration was seen to improve levitated CT lifetime by around 50% over that with the original design field. Suppression of impurity influx to the plasma is thought to be a significant factor in the improvement, as supported by spectrometer data. Improved levitation field may reduce the amount of edge plasma and current that intersects the insulating outer wall during the formation process. Higher formation current and stuffing field, and correspondingly higher CT flux, was possible with the improved configuration. Significant field and density compression factors were routinely observed. The level of MHD activity was reduced, and lifetime was increased further by matching the decay rate of the levitation field to that of the CT fields. Details of experimental results and comparisons to equilibrium models and MHD simulations will be presented.

  17. Neutron diffraction investigations of zero-field and field-induced magnetic structures of DyNiSn single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Murogaki, K. [Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan)]. E-mail: murogaki@fiberbit.net; Kawano, S. [Research Reactor Institute, Kyoto University, Osaka 590-0494 (Japan); Andoh, Y. [Faculty of Regional Sciences, Tottori University, Tottori 680-8551 (Japan); Takahashi, M. [Institute of Materials Science, University of Tsukuba, Ibaraki 305-8573 (Japan); Kurisu, M. [Japan Advanced Institute of Science and Technology, Ishikawa 923-1292 (Japan); Nakamoto, G. [Japan Advanced Institute of Science and Technology, Ishikawa 923-1292 (Japan); Anh, D.T. Kim [Japan Advanced Institute of Science and Technology, Ishikawa 923-1292 (Japan); Tsutaoka, T. [Graduate School of Education, Hiroshima University, Hiroshima 739-8524 (Japan)

    2006-02-09

    Single crystal neutron diffraction studies have been performed on the rare-earth ternary compound, DyNiSn. This crystal exhibits an incommensurate magnetic structure expressed by the propagation vector, Q = (0.662 0.352 0) with its third harmonics at low temperatures. In an external magnetic field applied along the c-axis DyNiSn shows incommensurate modulation with Q = (1 0.315 0) at 1.6 K, while along the easy magnetization direction of the b-axis a commensurate modulation with Q = (2/3 0 0) develops at 2 K. The results along the b-axis are fully consistent with the magnetization curve.

  18. Determination of the magnetic structure of CePt2In7 by means of neutron diffraction

    Science.gov (United States)

    Raba, M.; Ressouche, E.; Qureshi, N.; Colin, C. V.; Nassif, V.; Ota, S.; Hirose, Y.; Settai, R.; Rodière, P.; Sheikin, I.

    2017-04-01

    The magnetic structure of the heavy fermion antiferromagnet CePt2In7 is determined using neutron diffraction. We find a magnetic wave vector qM=(1 /2 ,1 /2 ,1 /2 ) , which is temperature independent up to TN=5.5 K. A staggered moment of 0.45 (1 ) μB at 2 K resides on the Ce ion. The nearest-neighbor moments in the tetragonal basal plane are aligned antiferromagnetically. The moments rotate by 90∘ from one CeIn3 plane to another along the c axis. A much weaker satellite peak with an incommensurate magnetic wave vector qM=(1 /2 ,1 /2 ,0.47 ) seems to develop at low temperature. However, the experimental data available so far are not sufficient to draw a definitive conclusion about the possible coexistence of commensurate and incommensurate magnetic structures in this material.

  19. Neutron diffraction texture analysis for {alpha}-Al{sub 2}O{sub 3} oriented by high magnetic field and sintering

    Energy Technology Data Exchange (ETDEWEB)

    Terada, N; Suzuki, H S; Suzuki, T S; Kitazawa, H; Sakka, Y [National Institute for Materials Science, Tsukuba, Ibaraki 305-0047 (Japan); Kaneko, K; Metoki, N [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)], E-mail: TERADA.Noriki@nims.go.jp

    2009-05-21

    We have performed neutron diffraction experiments on highly oriented {alpha}-Al{sub 2}O{sub 3}, obtained by slip casting under a magnetic field and sintering. In order to investigate the magnetic field, B, and sintering temperature, T{sub sint}, dependence of the degree of alignment of the orientation, we used samples treated with systematically varied B up to 12 T and T{sub sint} up to 1600 deg. C. The degree of alignment of the magnetic easy axis (the hexagonal c-axis) is rapidly enhanced by sintering above 1200 deg. C, which is coincident with the temperature at which crystal grains start to grow. The angular distribution of the c-axis for the sample sintered at 1600 deg. C, obtained by {omega}-scan neutron diffraction profiles, is almost coincident with the probability distribution calculated for the particle size two times larger than that in the starting material. We discuss the orientation process mechanism with sintering in light of the results of this analysis.

  20. Magnetized laboratory plasma jets: Experiment and simulation

    Science.gov (United States)

    Schrafel, Peter; Bell, Kate; Greenly, John; Seyler, Charles; Kusse, Bruce

    2015-01-01

    Experiments involving radial foils on a 1 M A , 100 n s current driver can be used to study the ablation of thin foils and liners, produce extreme conditions relevant to laboratory astrophysics, and aid in computational code validation. This research focuses on the initial ablation phase of a 20 μ m Al foil (8111 alloy), in a radial configuration, driven by Cornell University's COBRA pulsed power generator. In these experiments ablated surface plasma (ASP) on the top side of the foil and a strongly collimated axial plasma jet are observed developing midway through the current rise. With experimental and computational results this work gives a detailed description of the role of the ASP in the formation of the plasma jet with and without an applied axial magnetic field. This ˜1 T field is applied by a Helmholtz-coil pair driven by a slow, 150 μ s current pulse and penetrates the load hardware before arrival of the COBRA pulse. Several effects of the applied magnetic field are observed: (1) without the field extreme-ultraviolet emission from the ASP shows considerable azimuthal asymmetry while with the field the ASP develops azimuthal motion that reduces this asymmetry, (2) this azimuthal motion slows the development of the jet when the field is applied, and (3) with the magnetic field the jet becomes less collimated and has a density minimum (hollowing) on the axis. PERSEUS, an XMHD code, has qualitatively and quantitatively reproduced all these experimental observations. The differences between this XMHD and an MHD code without a Hall current and inertial effects are discussed. In addition the PERSEUS results describe effects we were not able to resolve experimentally and suggest a line of future experiments with better diagnostics.

  1. Neutron diffraction studies of the magnetic structure of Ho{sub 3}Pd{sub 4}Ge{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Wawrzynska, E.; Penc, B.; Hernandez-Velasco, J.; Szytula, A.; Zygmunt, A

    2003-02-17

    Ho{sub 3}Pd{sub 4}Ge{sub 4} crystallizes in the orthorhombic Gd{sub 6}Cu{sub 8}Ce{sub 8}-type of structure (space group Immm) in which the Ho atoms occupy two nonequivalent crystallographic positions: 2a and 4j. Neutron diffraction measurements indicate that the Ho moments in the 4j site below 6.7 K form a collinear antiferromagnetic structure with the magnetic moments parallel to the a axis, whereas the Ho moments in the 2a site below 5 K form a sine-wave modulated structure with the magnetic moments parallel to the c axis.

  2. Energy-dispersive neutron imaging and diffraction of magnetically driven twins in a Ni2MnGa single crystal magnetic shape memory alloy

    Science.gov (United States)

    Kabra, Saurabh; Kelleher, Joe; Kockelmann, Winfried; Gutmann, Matthias; Tremsin, Anton

    2016-09-01

    Single crystals of a partially twinned magnetic shape memory alloy, Ni2MnGa, were imaged using neutron diffraction and energy-resolved imaging techniques at the ISIS spallation neutron source. Single crystal neutron diffraction showed that the crystal produces two twin variants with a specific crystallographic relationship. Transmission images were captured using a time of flight MCP/Timepix neutron counting detector. The twinned and untwinned regions were clearly distinguishable in images corresponding to narrow-energy transmission images. Further, the spatially-resolved transmission spectra were used to elucidate the orientations of the crystallites in the different volumes of the crystal.

  3. Neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Heger, G. [Rheinisch-Westfaelische Technische Hochschule Aachen, Inst. fuer Kristallographie, Aachen (Germany)

    1996-12-31

    X-ray diffraction using conventional laboratory equipment and/or synchrotron installations is the most important method for structure analyses. The purpose of this paper is to discuss special cases, for which, in addition to this indispensable part, neutrons are required to solve structural problems. Even though the huge intensity of modern synchrotron sources allows in principle the study of magnetic X-ray scattering the investigation of magnetic structures is still one of the most important applications of neutron diffraction. (author) 15 figs., 1 tab., 10 refs.

  4. Magnetized plasma jets in experiment and simulation

    Science.gov (United States)

    Schrafel, Peter; Greenly, John; Gourdain, Pierre; Seyler, Charles; Blesener, Kate; Kusse, Bruce

    2013-10-01

    This research focuses on the initial ablation phase of a thing (20 micron) Al foil driven on the 1 MA-in-100 ns COBRA through a 5 mm diameter cathode in a radial configuration. In these experiments, ablated surface plasma (ASP) on the top of the foil and a strongly collimated axial plasma jet can be observed developing midway through current-rise. Our goal is to establish the relationship between the ASP and the jet. These jets are of interest for their potential relevance to astrophysical phenomena. An independently pulsed 200 μF capacitor bank with a Helmholtz coil pair allows for the imposition of a slow (150 μs) and strong (~1 T) axial magnetic field on the experiment. Application of this field eliminates significant azimuthal asymmetry in extreme ultraviolet emission of the ASP. This asymmetry is likely a current filamentation instability. Laser-backlit shadowgraphy and interferometry confirm that the jet-hollowing is correlated with the application of the axial magnetic field. Visible spectroscopic measurements show a doppler shift consistent with an azimuthal velocity in the ASP caused by the applied B-field. Computational simulations with the XMHD code PERSEUS qualitatively agree with the experimental results.

  5. Experiments in Nuclear Magnetic Resonance Microscopy

    Science.gov (United States)

    Lee, Yong; Lu, Wei; Choi, J.-H.; Chia, H. J.; Mirsaidov, U. M.; Guchhait, S.; Cambou, A. D.; Cardenas, R.; Park, K.; Markert, J. T.

    2006-03-01

    We report our group's effort in the construction of an 8-T, ^3 He cryostat based nuclear magnetic resonance force microscope (NMRFM). The probe has two independent 3-D of piezoelectric x-y-z positioners for precise positioning of a fiber optic interferometer and a sample/gradient-producing magnet with respect to a micro-cantilever. The piezoelectric positioners have a very uniform controllable step size with virtually no backlash. A novel RF tuning circuit board design is implemented which allows us to simply swap out one RF component board with another for experiments involving different nuclear species. We successfully fabricated and are characterizing 50μm x50μm x0.2μm double torsional oscillators. We have also been characterizing ultrasoft cantilevers whose spring constant is on the order of 10-4 N/m. We also report NMRFM data for ammonium dihydrogen phosphate(ADP) at room temperature using our 1.2-T system. Observed features include the correct shift of the NMR peak with carrier frequency, increases in signal amplitude with both RF field strength and frequency modulation amplitude, and signal oscillation (spin nutation) as a function of tipping RF pulse length. Experiments in progress on NH4MgF3 (at 1.2 T) and MgB2 (at 8.1 T) will also be briefly reviewed. Robert A. Welch Foundation grant No.F-1191 and the National Science Foundation grant No. DMR-0210383.

  6. Magnetic structure of La2O3FeMnSe2: neutron diffraction and physical property measurements.

    Science.gov (United States)

    Landsgesell, S; Blumenröther, E; Prokeš, K

    2013-02-27

    We report on the characterization of the mixed layered lanthanum iron manganese oxyselenide La(2)O(3)FeMnSe(2), where Fe and Mn share the same crystallographic position. The susceptibility data show a magnetic transition temperature of 76 K and a strong difference between field cooled and zero field cooled (ZFC) data at low fields. While the ZFC magnetization curve exhibits negative values below about 45 K, hysteresis measurement reveals, after an initial negative magnetic moment, a hysteresis loop typical for ferromagnetic material, pointing to competing ferromagnetic and antiferromagnetic interactions. Resistivity and dielectric permittivity measurements indicate that La(2)O(3)FeMnSe(2) is a semiconductor. We performed x-ray diffraction at 295 K and neutron diffraction at 90 and 1.7 K. The nuclear and magnetic structure was refined in the space group I4/mmm with a = 4.11031 (3) Å and c = 18.7613 (2) Å at 295 K. We did not detect a structural distortion and the Fe and Mn atoms were randomly distributed. The magnetic order was found to be antiferromagnetic, with a propagation vector q = (0,0,0) and magnetic moments of 3.44 (5) μ(B) per Fe/Mn atom aligned within the a-b plane. This magnetic order is different with respect to the pure Fe or Mn compositions reported in other studies.

  7. Magnetic ordering of ScMn{sub 6}Ge{sub 6} by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Schobinger-Papamantellos, P., E-mail: Schobinger@mat.ethz.ch [Laboratory of Crystallography, ETH-Zürich, 8093 Zürich (Switzerland); Rodríguez-Carvajal, J. [Institut Laue-Langevin, CS 20156, 38042 Grenoble Cedex (France); Buschow, K.H.J. [Van der Waals-Zeeman Institute, University of Amsterdam, NL-1018 XE The Netherlands (Netherlands)

    2014-11-15

    The compound ScMn{sub 6}Ge{sub 6} (HfFe{sub 6}Ge{sub 6}-type, P6/mmm) orders antiferromagnetically below T{sub N}=516 K. Neutron powder diffraction at various temperatures 1.5–309 K shows the existence of two distinct magnetic ordering ranges described by the commensurate q{sub 1}=(0, 0, 1/2) and the incommensurate q{sub 2}=(0, 0, q{sub z}) vectors: (i) the HT (high temperature) T{sub t}≈100 KT>1.5 K range has an easy double-cone incommensurately modulated structure described by two vectors (q{sub 1}, q{sub 2}). At 1.5 K q{sub 2}=(0, 0, 0.405(1)), the spiral angle is Φ=145.8° the cone half angle is α≈8° and the ordered moment value μ{sub Mn}=2.12(2) μ{sub B} is the same as for the isomorphic RMn{sub 6}Ge{sub 6} (R=heavy rare earth) compounds. The 1.5 K q{sub 2} satellites are very weak as the in-plane moment component measures only 0.31 μ{sub B}. - Highlights: • T-magnetic phase diagram of antiferromagnetic (afmg.) ScMn{sub 6}Ge{sub 6} compound (T{sub N}=516 K). • 1.5–309 K neutron patterns detected two propagation vectors: q{sub 1}=(0, 0, 1/2) and INC q{sub 2}=(0, 0, q{sub z}). • The HT T{sub t}≈100–309 K range with q{sub 1} has a+− −+Mn moment stacking ||c at z∼1/4, 3/4, 5/4, and 7/4. • The LT range T{sub t}−1.5 K has an easy double cone INC structure requiring both vectors. • At 1.5 K, q{sub 2}=(0, 0, 0.405(1)), the cone half angle 8° and μ{sub Mn}=2.12(2) μ{sub B}.

  8. Coil-type Fano Resonances: a Plasmonic Approach to Magnetic Sub-diffraction Confinement

    KAUST Repository

    Panaro, Simone

    2015-05-10

    Matrices of nanodisk trimers are introduced as plasmonic platforms for the generation of localized magnetic hot-spots. In Fano resonance condition, the optical magnetic fields can be squeezed in sub-wavelength regions, opening promising scenarios for spintronics.

  9. Comparison between magnetic force microscopy and electron back-scatter diffraction for ferrite quantification in type 321 stainless steel.

    Science.gov (United States)

    Warren, A D; Harniman, R L; Collins, A M; Davis, S A; Younes, C M; Flewitt, P E J; Scott, T B

    2015-01-01

    Several analytical techniques that are currently available can be used to determine the spatial distribution and amount of austenite, ferrite and precipitate phases in steels. The application of magnetic force microscopy, in particular, to study the local microstructure of stainless steels is beneficial due to the selectivity of this technique for detection of ferromagnetic phases. In the comparison of Magnetic Force Microscopy and Electron Back-Scatter Diffraction for the morphological mapping and quantification of ferrite, the degree of sub-surface measurement has been found to be critical. Through the use of surface shielding, it has been possible to show that Magnetic Force Microscopy has a measurement depth of 105-140 nm. A comparison of the two techniques together with the depth of measurement capabilities are discussed.

  10. Evolution of the magnetic order in the Ho(Mn, Al) sub 2 system; neutron diffraction study

    CERN Document Server

    Golosovsky, I V; Markosyan, A S; Roisnel, T

    2002-01-01

    The neutron diffraction study of Ho(Mn sub 1 sub - sub x Al sub x) sub 2 shows the coexistence of two cubic Laves phases with different unit-cell parameters and substantially different magnetic behaviours. The first phase combines ordered ferrimagnetic and disordered antiferromagnetic components of the magnetic moments. With increasing Al content, starting from the long-range ferrimagnetic order with the induced Mn moment in HoMn sub 2 , the progressive formation of spontaneous Mn moments yields short-range order, which in turn transforms to ferromagnetic order in HoAl sub 2. The second phase with incommensurate magnetic structure is driven by the spontaneous Mn moments and exists only over limited ranges of Al content and unit-cell parameter. It has a finite correlation length and appears from a second-order transition without a magneto-volume effect.

  11. Magnetic Field Saturation in the Riga Dynamo Experiment

    CERN Document Server

    Gailitis, A; Platacis, E; Dementev, S; Cifersons, A; Gerbeth, G; Gundrum, T; Stefani, F; Christen, M; Will, G; Gailitis, Agris; Lielausis, Olgerts; Platacis, Ernests; Dement'ev, Sergej; Cifersons, Arnis; Gerbeth, Gunter; Gundrum, Thomas; Stefani, Frank; Christen, Michael; Will, Gotthard

    2001-01-01

    After the dynamo experiment in November 1999 had shown magnetic field self-excitation in a spiraling liquid metal flow, in a second series of experiments emphasis was placed on the magnetic field saturation regime as the next principal step in the dynamo process. The dependence of the strength of the magnetic field on the rotation rate is studied. Various features of the saturated magnetic field are outlined and possible saturation mechanisms are discussed.

  12. Experiments performed in order to reveal fundamental differences between the diffraction and interference of waves and electrons

    CERN Document Server

    Demjanov, Victor V

    2010-01-01

    Diffraction patterns of electrons are believed to resemble those of electromagnetic waves (EMW). I performed a series of experiments invoked to show that the periodicity of peaks in the diffraction diagram of electrons is concerned with the periodicity of the arrangement of scattering centers in the diffraction grating in combination with the supposed character of the spatial structure of the electron as a system of regularly spaced concentric shells of elasticity. I started from the experiment on the diffraction of electrons and EMWs at the sharp edge of the opaque half-plane. This simple scattering configuration enabled me to discriminate between the re-radiation mechanism of the wave diffraction and ricochet scattering of electrons on the edge of the half-plane. Then I made experiments with scattering on composite objects proceeding step by step from a single straight edge to a couple of edges (one slit) and then to four edges (two slits). Thus I succeeded in interpretation of the double-slit diffraction (...

  13. Commensurate magnetic structures of RMn2O5 (R=Y,Ho,Bi) determined by single-crystal neutron diffraction

    Science.gov (United States)

    Vecchini, C.; Chapon, L. C.; Brown, P. J.; Chatterji, T.; Park, S.; Cheong, S.-W.; Radaelli, P. G.

    2008-04-01

    Precise magnetic structures of RMn2O5 , with R=Y,Ho,Bi in the commensurate and/or ferroelectric regime, have been determined by single-crystal neutron diffraction. For each system, the integrated intensities of a large number of independent magnetic Bragg reflections have been measured, allowing unconstrained least-squares refinement of the structures. The analysis confirms the previously reported magnetic configuration in the ab plane, in particular, the existence of zigzag antiferromagnetic chains. For the Y and Ho compounds, additional weak magnetic components parallel to the c axis were detected, which are modulated in phase quadrature with the a-b components. This component is extremely small in the BiMn2O5 sample, therefore supporting symmetric exchange as the principal mechanism inducing ferroelectricity. For HoMn2O5 , a magnetic ordering of the Ho moments was observed, which is consistent with a superexchange interaction through the oxygens. For all three compounds, the point symmetry in the magnetically ordered state is m2m , allowing the polar b axis found experimentally.

  14. New neutron diffraction results on magnetic properties of the cubic rare earth compounds HoP and PrX/sub 2/ (X = Ru, Rh, Ir, Pt)

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, P.; Haelg, W.; Kaldis, E.; Greidanus, F.J.A.M.; Buschow, K.H.J.

    1982-01-01

    Neutron diffraction studies performed on polycrystalline, NaCl type HoP in external magnetic fields yield <100> as easy directions of magnetization in the ferromagnetic state. The magnetic ordering of the MgCu/sub 2/ type Laves phase systems PrX/sub 2/ (X = Ru, Rh, Ir, Pt) was investigated on powdered samples by means of neutron diffraction. Simple ferromagnetic structures were observed. The determined Curie temperatures confirm bulk measurements, and the values of the ordered magnetic moments indicate crystal field effects.

  15. New neutron diffraction results on magnetic properties of the cubic rare earth compounds HoP and PrX2 (X=Ru, Rh, Ir, Pt)

    Science.gov (United States)

    Fischer, P.; Hälg, W.; Kaldis, E.; Greidanus, F. J. A. M.; Buschow, K. H. J.

    1982-09-01

    Neutron diffraction studies performed on polycrystalline, NaCl type HoP in external magnetic fields yield as easy directions of magnetization in the ferromagnetic state. The magnetic ordering of the MgCu2 type Laves phase systems PrX2 (X=Ru, Rh, Ir, Pt) was investigated on powdered samples by means of neutron diffraction. Simple ferromagnetic structures were observed. The determined Curie temperatures confirm bulk measurements, and the values of the ordered magnetic moments indicate crystal field effects.

  16. ALICE Diffractive Detector Control System for RUN-II in the ALICE Experiment

    Science.gov (United States)

    Cabanillas, J. C.; Martínez, M. I.; León, I.

    2016-10-01

    The ALICE Diffractive (AD0) detector has been installed and commissioned for the second phase of operation (RUN-II). With this new detector it is possible to achieve better measurements by expanding the range of pseudo-rapidity in which the production of particles can be detected. Specifically the selection of diffractive events in the ALICE experiment which was limited by the range over which rapidity gaps occur. Any new detector should be able to take data synchronously with all other detectors and to be operated through the ALICE central systems. One of the key elements developed for the AD0 detector is the Detector Control System (DCS). The DCS is designed to operate safely and correctly this detector. Furthermore, the DCS must also provide optimum operating conditions for the acquisition and storage of physics data and ensure these are of the highest quality. The operation of AD0 implies the configuration of about 200 parameters, as electronics settings and power supply levels and the generation of safety alerts. It also includes the automation of procedures to get the AD0 detector ready for taking data in the appropriate conditions for the different run types in ALICE. The performance of AD0 detector depends on a certain number of parameters such as the nominal voltages for each photomultiplier tube (PMT), the threshold levels to accept or reject the incoming pulses, the definition of triggers, etc. All these parameters affect the efficiency of AD0 and they have to be monitored and controlled by the AD0 DCS.

  17. Neutron diffraction and electrical transport studies on the incommensurate magnetic phase transition in holmium at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Sarah [University of Alabama, Birmingham; Uhoya, Walter [University of Alabama, Birmingham; Tsoi, Georgiy [University of Alabama, Birmingham; Wenger, Lowell E [University of Alabama, Birmingham; Vohra, Yogesh [University of Alabama, Birmingham; Chesnut, Gary Neal [University of Alabama, Birmingham; Weir, S. T. [Lawrence Livermore National Laboratory (LLNL); Tulk, Christopher A [ORNL; Moreira Dos Santos, Antonio F [ORNL

    2012-01-01

    Neutron diffraction and electrical transport measurements have been made on the heavy rare earth metal holmium at high pressures and low temperatures in order to elucidate its transition from a paramagnetic (PM) to a helical antiferromagnetic (AFM) ordered phase as a function of pressure. The electrical resistance measurements show a change in the resistance slope as the temperature is lowered through the antiferromagnetic Neel temperature. The temperature of this antiferromagnetic transition decreases from approximately 122 K at ambient pressure at a rate of -4.9 K GPa(-1) up to a pressure of 9 GPa, whereupon the PM-to-AFM transition vanishes for higher pressures. Neutron diffraction measurements as a function of pressure at 89 and 110 K confirm the incommensurate nature of the phase transition associated with the antiferromagnetic ordering of the magnetic moments in a helical arrangement and that the ordering occurs at similar pressures as determined from the resistance results for these temperatures.

  18. Effects of dynamic diffraction conditions on magnetic parameter determination in a double perovskite Sr2FeMoO6 using electron energy-loss magnetic chiral dichroism.

    Science.gov (United States)

    Wang, Z C; Zhong, X Y; Jin, L; Chen, X F; Moritomo, Y; Mayer, J

    2017-05-01

    Electron energy-loss magnetic chiral dichroism (EMCD) spectroscopy, which is similar to the well-established X-ray magnetic circular dichroism spectroscopy (XMCD), can determine the quantitative magnetic parameters of materials with high spatial resolution. One of the major obstacles in quantitative analysis using the EMCD technique is the relatively poor signal-to-noise ratio (SNR), compared to XMCD. Here, in the example of a double perovskite Sr2FeMoO6, we predicted the optimal dynamical diffraction conditions such as sample thickness, crystallographic orientation and detection aperture position by theoretical simulations. By using the optimized conditions, we showed that the SNR of experimental EMCD spectra can be significantly improved and the error of quantitative magnetic parameter determined by EMCD technique can be remarkably lowered. Our results demonstrate that, with enhanced SNR, the EMCD technique can be a unique tool to understand the structure-property relationship of magnetic materials particularly in the high-density magnetic recording and spintronic devices by quantitatively determining magnetic structure and properties at the nanometer scale. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Test experiment to search for a neutron EDM by the Laue diffraction method

    CERN Document Server

    Fedorov, V V; Lelievre-Berna, E; Nesvizhevsky, V V; Petoukhov, A; Semenikhin, S Y; Soldner, T; Tasset, F; Voronin, V V

    2005-01-01

    A prototype experiment to measure the neutron electric dipole moment (nEDM) by spin-rotation in a non-centrosymmetric crystal in Laue geometry was carried out in order to investigate the statistical sensitivity and systematic effects of the method. The statistical sensitivity to the nEDM was about $6\\cdot 10^{-24}$ e$\\cdot $cm per day and can be improved by one order of magnitude for the full scale setup. Systematics was limited by the homogeneity of the magnetic field in the crystal region and by a new kind of spin rotation effect. We attribute this effect to a difference of the two Bloch waves amplitudes in the crystal, which is caused by the presence of a small crystal deformation due to a temperature gradient. In a revised scheme of the experiment, this effect could be exploited for a purposeful manipulation of the Bloch waves.

  20. Crystal and magnetic structures of Cr{sub 1∕3}NbSe{sub 2} from neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Gubkin, A. F., E-mail: agubkin@imp.uran.ru; Baranov, N. V. [M.N. Miheev Institute of Metal Physics, Russian Academy of Sciences, 620990 Yekaterinburg (Russian Federation); Institute of Natural Sciences, Ural Federal University, 620083 Yekaterinburg (Russian Federation); Proskurina, E. P.; Sherokalova, E. M.; Selezneva, N. V. [Institute of Natural Sciences, Ural Federal University, 620083 Yekaterinburg (Russian Federation); Kousaka, Y.; Akimitsu, J. [Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Center for Chiral Science, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Miao, P.; Lee, S.; Ishikawa, Y.; Torii, S. [Institute of Materials Structure Science, KEK, Tokai, Ibaragi 319-1106 (Japan); Zhang, J. [Institute of Materials Structure Science, KEK, Tokai, Ibaragi 319-1106 (Japan); China Spallation Neutron Source, Institute of High Energy Physics, Chinese Academy of Sciences, Dongguan 523803, Guangdong (China); Kamiyama, T. [Institute of Materials Structure Science, KEK, Tokai, Ibaragi 319-1106 (Japan); Sokendai (Graduate University for Advanced Studies), KEK, Tokai, Ibaragi 319-1106 (Japan); Campo, J. [Aragón Materials Science Institute (CSIC - University of Zaragoza), 50009 Zaragoza (Spain)

    2016-01-07

    Neutron diffraction measurements of the Cr intercalated niobium diselenide Cr{sub 1∕3}NbSe{sub 2} together with magnetization measurements have revealed that this compound exhibits ferromagnetic ordering below T{sub C} = 96 K unlike a chiral helimagnetic order observed in the sulfide compound Cr{sub 1∕3}NbS{sub 2}. As derived from neutron diffraction data, the Cr magnetic moments μ{sub Cr} = 2.83 ± 0.03 μ{sub B} in Cr{sub 1∕3}NbSe{sub 2} are aligned within basal plane. The discrepancy in the magnetic states of Cr{sub 1∕3}NbS{sub 2} and Cr{sub 1∕3}NbSe{sub 2} is ascribed to the difference in the preferential site occupation of Cr ions in crystal lattices. In Cr{sub 1∕3}NbSe{sub 2}, the Cr ions are predominantly distributed over 2b Wyckoff site, which determines a centrosymmetric character of the crystal structure unlike Cr{sub 1∕3}NbS{sub 2}, where the Cr ions are mainly located in 2c position and the crystal structure is non-centrosymmetric.

  1. Neutron diffraction evidence for kinetic arrest of first order magneto-structural phase transitions in some functional magnetic materials.

    Science.gov (United States)

    Siruguri, V; Babu, P D; Kaushik, S D; Biswas, Aniruddha; Sarkar, S K; Krishnan, Madangopal; Chaddah, P

    2013-12-11

    Neutron diffraction measurements, performed in the presence of an external magnetic field, have been used to show structural evidence for the kinetic arrest of the first order phase transition from (i) the high temperature austenite phase to the low temperature martensite phase in the magnetic shape memory alloy Ni37Co11Mn42.5Sn9.5, (ii) the higher temperature ferromagnetic phase to the lower temperature antiferromagnetic phase in the half-doped charge ordered compound La0.5Ca0.5MnO3 and (iii) the formation of glass-like arrested states in both compounds. The cooling and heating under unequal fields protocol has been used to establish phase coexistence of metastable and equilibrium states, and also to demonstrate the devitrification of the arrested metastable states in the neutron diffraction patterns. We also explore the field–temperature dependent kinetic arrest line TK(H), through the transformation of the arrested phase to the equilibrium phase. This transformation has been observed isothermally in reducing H, as also on warming in constant H. TK is seen to increase as H increases in both cases, consistent with the low-T equilibrium phase having lower magnetization.

  2. Consistent first-principles pressure scales for diffraction experiments under extreme conditions

    Science.gov (United States)

    Otero-de-La-Roza, Alberto; Cabal, Victor Lua Na

    2012-02-01

    Diamond anvil cell (DAC) diffraction experiments are fundamental in geophysics and materials science to explore the behavior of solids under very high pressures and temperatures. A factor limiting the accuracy of DAC experiments is the lack of an accurate pressure scale for the calibration materials that extends to the ever-increasing pressure and temperature limits of the technique. In this communication, we address this problem by applying a newly developed technique that allows the calculation of accurate thermodynamic properties from first-principles calculations [Phys. Rev. B 84 (2011) 024109, 84 (2011) 184103]. Three elements are key in this method: i) the quasiharmonic approximation (QHA) and the static energies and phonon frequencies obtained from an electronic structure calculation ii) the appropriate representation of the equation of state by using averages of strain polynomials and iii) the correction of the systematic errors caused by the exchange-correlation functional approximation. As a result, we propose accurate equations of scale for typical pressure calibrants that can be used in the whole experimental range of pressures and temperatures. The internal consistency and the agreement with the ruby scale based on experimental data is examined.

  3. Minimizing magnetic fields for precision experiments

    CERN Document Server

    Altarev, I; Lins, T; Marino, M G; Nießen, B; Petzoldt, G; Reisner, M; Stuiber, S; Sturm, M; Singh, J T; Taubenheim, B; Rohrer, H K; Schläpfer, U

    2015-01-01

    An increasing number of measurements in fundamental and applied physics rely on magnetically shielded environments with sub nano-Tesla residual magnetic fields. State of the art magnetically shielded rooms (MSRs) consist of up to seven layers of high permeability materials in combination with highly conductive shields. Proper magnetic equilibration is crucial to obtain such low magnetic fields with small gradients in any MSR. Here we report on a scheme to magnetically equilibrate MSRs with a 10 times reduced duration of the magnetic equilibration sequence and a significantly lower magnetic field with improved homogeneity. For the search of the neutron's electric dipole moment, our finding corresponds to a linear improvement in the systematic reach and a 40 % improvement of the statistical reach of the measurement. However, this versatile procedure can improve the performance of any MSR for any application.

  4. Characterization of thin-film multilayers using magnetization curves and modeling of low-angle X-ray diffraction data

    Energy Technology Data Exchange (ETDEWEB)

    Lane, M. [Emory & Henry College, VA (United States); Chaiken, A.; Michel, R.P. [Lawrence Livermore National Lab., CA (United States)

    1994-12-01

    We have characterized thin-film multilayers grown by ion-beam sputtering using magnetization curves and modeling of low-angle x-ray diffraction data. In our films, we use ferromagnetic layer = Co, Fe, and NiFe and spacer layer = Si, Ge, FeSi{sub 2}, and CoSi{sub 2}. We have studied the effects of (1) deposition conditions; (2) thickness of layers; (3) different layer materials; and (4) annealing. We find higher magnetization in films grown at 1000V rather than 500V and in films with spacer layers of 50{angstrom} rather than 100{angstrom}. We find higher coercivity in films with cobalt grown on germanium rather than silicon, metal grown on gold underlayers rather than on glass substrates, and when using thinner spacer layers. Finally, modeling reveals that films grown with disilicide layers are more thermally stable than films grown with silicon spacer layers.

  5. Experiences with making diffraction image data available : What metadata do we need to archive?

    NARCIS (Netherlands)

    Kroon - Batenburg, Louise; Helliwell, John R.

    2014-01-01

    Recently, the IUCr (International Union of Crystallography) initiated the formation of a Diffraction Data Deposition Working Group with the aim of developing standards for the representation of raw diffraction data associated with the publication of structural papers. Archiving of raw data serves se

  6. Producing acoustic 'Frozen Waves': Simulated experiments with diffraction/attenuation resistant beams, in lossy media

    CERN Document Server

    Prego-Borges, Jose' L; Recami, Erasmo; Tavares-Costa, Eduardo

    2013-01-01

    The so-called Localized Waves (LW), and the "Frozen Waves" (FW), have arisen significant attention in the areas of Optics and Ultrasound, because of their surprising energy localization properties. The LWs resist the effects of diffraction for large distances, and possess an interesting self-reconstruction (self-healing) property, after obstacles with size smaller than the antenna's; while the FWs, a sub-class of theirs, offer the possibility of arbitrarily modeling the field longitudinal intensity pattern inside a prefixed interval, for instance 0 < z < L, of the wave propagation axis. More specifically, the FWs are localized fields "at rest", that is, with a static envelope (within which only the carrier wave propagates), and can be endowed moreover with a high transverse localization. In this paper we investigate by simulated experiments, various cases of generation of ultrasonic FW fields, with frequency f_o = 1 MHz in a water-like medium, taking account of the effects of attenuation. We present res...

  7. Gamma-ray and neutron diffraction studies of CoF2: magnetostriction, electron density and magnetic moments.

    Science.gov (United States)

    Jauch, W; Reehuis, M; Schultz, A J

    2004-01-01

    Accurate structure factors up to sin theta/lambda = 1.6 A(-1) have been measured with 316.5 keV gamma-rays from CoF(2), both at room temperature and in the antiferromagnetic state at 10 K. The same crystal was used to collect extended time-of-flight neutron diffraction data in the two magnetic states, which allowed an accurate determination of the fluorine positional parameter. For room temperature, the standard structural parameters are reported. At 10 K, a complete charge-density study has been carried out. The total number of 3d electrons on Co is found to be 6.95 (3). The experimental populations of the d orbitals agree with expectation from crystal field theory. The fluorine valence region exhibits a strong dipolar deformation. Electronic properties at the bond critical points and integrated atomic properties are derived from the static model electron density, revealing the Co-F interactions as purely ionic. On magnetic ordering, a shift of the fluorine ions of 1.5 (4) x 10(-3) A is found which confirms a prediction from theory of optical birefringence. The effect of magnetostriction on the distortion of the ligand coordination octahedra is compared for the late members of the 3d transition-metal difluorides. From neutron powder diffraction, an ordered magnetic moment of 2.60 (4) mu(B) per cobalt ion is found. Despite the strong deviation from the ideal spin value of 3 mu(B), there is still an appreciable orbital contribution to the local magnetic moment.

  8. Electron tomography and nano-diffraction enabling the investigation of individual magnetic nanoparticles inside fibers of MR visible implants

    Science.gov (United States)

    Slabu, I.; Wirch, N.; Caumanns, T.; Theissmann, R.; Krüger, M.; Schmitz-Rode, T.; Weirich, T. E.

    2017-08-01

    Superparamagnetic iron oxide nanoparticles (SPIONPs) incorporated into the base material of implants are used as contrast agents in magnetic resonance imaging for the delineation of the implants from the surrounding tissue. However, the delineation quality is strongly related to the structural characteristics of the incorporated SPIONPs and their interparticle interaction as well as their interaction with the polymer matrix of the implant. Consequently, a profound knowledge of the formation of aggregates inside the polymer matrix, which are responsible for strong interparticle interactions, and of their structural characteristics, is required for controlling the magnetic resonance image quality of the implants. In this work, transmission electron microscopy methods such as electron tomography and nano-electron diffraction were used to depict SPIONP aggregates inside the melt-spin polyvinylidene fluoride fibers used for the assembly of implants and to determine the crystal structure of individual nanocrystals inside these aggregates, respectively. Using these techniques it was possible for the first time to characterize the aggregates inside the fibers of implants and to validate the magnetization measurements that have been previously used to assess the interaction phenomena inside the fibers of implants. With electron tomography, inhomogeneously sized distributed aggregates were delineated and 3D models of these aggregates were constructed. Furthermore, the distribution of the aggregates inside the fibers was verified by means of magnetic force microscopy. With nano-diffraction measurements, the SPIONP crystal structure inside the fibers of the implant could not be clearly assigned to that of magnetite (Fe3O4) or maghemite (γ-Fe2O3). Therefore, additional electron energy loss spectroscopy measurements were performed, which revealed the presence of both phases of Fe3O4 and γ-Fe2O3, probably caused by oxidation processes during the manufacture of the fibers by

  9. Nanosecond x-ray Laue diffraction apparatus suitable for laser shock compression experiments.

    Science.gov (United States)

    Suggit, Matthew; Kimminau, Giles; Hawreliak, James; Remington, Bruce; Park, Nigel; Wark, Justin

    2010-08-01

    We have used nanosecond bursts of x-rays emitted from a laser-produced plasma, comprised of a mixture of mid-Z elements, to produce a quasiwhite-light spectrum suitable for performing Laue diffraction from single crystals. The laser-produced plasma emits x-rays ranging in energy from 3 to in excess of 10 keV, and is sufficiently bright for single shot nanosecond diffraction patterns to be recorded. The geometry is suitable for the study of laser-shocked crystals, and single-shot diffraction patterns from both unshocked and shocked silicon crystals are presented.

  10. Experiences with archived raw diffraction images data: capturing cisplatin after chemical conversion of carboplatin in high salt conditions for a protein crystal

    NARCIS (Netherlands)

    Tanley, S.W.M.; Diederichs, K.; Kroon-Batenburg, L.M.J.; Schreurs, A.M.M.; Helliwell, J.R.

    2013-01-01

    The archiving of raw diffraction images data is the focus of an IUCr Diffraction Data Deposition Working Group (see http://forums.iucr.org/). Experience in archiving and sharing of raw diffraction images data in collaboration between Manchester and Utrecht Universities, studying the binding of the i

  11. A Study of Diffractive Scattering with the ATLAS and ALFA Experiment

    CERN Document Server

    Lind, Alexander Pedersen

    This thesis presents a study of diffractive scattering of high-energy protons. Hadronic diffraction is not well-understood and many alternative approaches exist. The Monte Carlo event generator Pythia 8 follows a Pomeron-based approach, where the invariant mass of the diffractive system and the squared momentum transfer $t$ of the system is set up according to a phenomenological Pomeron flux parameterization, which is parameterized by the super-critical Pomeron trajectory, $\\alpha(t) = 1 + \\varepsilon + \\alpha' t$, where the intercept parameter $\\varepsilon$ and the slope parameter $\\alpha'$ can be tuned by the user. A fast detector response simulation of the ALFA and ATLAS detectors has been developed in the Rivet toolkit for the purposes of this thesis. The developed simulation framework is able to handle the beam transport of diffractively scattered protons as well as impose the kinematic acceptance of the ALFA detector which was found to be approximately $\\xi \\lesssim 0.22$, with a pseudorapidity coverag...

  12. Plants and Magnetism: Experiments with Biomagnetism

    Science.gov (United States)

    McCormack, Alan J.

    1972-01-01

    Phenomenon of effect of magnetic field on plant growth provides wide opportunities for research in classrooms. Using moderately powerful magnets, seed growth patterns can be observed in pre-germination treatment, germination period exposure and under many other conditions. Such research may enable understanding magnetotropism more clearly. (PS)

  13. Fun with magnets Experiments and Ideas

    CERN Document Server

    Davis, Claire

    2001-01-01

    This booklet has been produced as part of an Engineering and Physical Sciences Research Council (EPSRC) funded project under the heading of the Public Partnerships in Science. Magnets and magnetism appear in various places in the National Curriculum and the booklet provides ideas on some ways in which these topics can be approached.

  14. Laboratory experiments and numerical simulations on magnetic instabilities

    CERN Document Server

    Stefani, F; Kasprzyk, Ch; Paredes, A; Ruediger, G; Seilmayer, M

    2016-01-01

    Magnetic fields of planets, stars and galaxies are generated by self-excitation in moving electrically conducting fluids. Once produced, magnetic fields can play an active role in cosmic structure formation by destabilizing rotational flows that would be otherwise hydrodynamically stable. For a long time, both hydromagnetic dynamo action as well as magnetically triggered flow instabilities had been the subject of purely theoretical research. Meanwhile, however, the dynamo effect has been observed in large-scale liquid sodium experiments in Riga, Karlsruhe and Cadarache. In this paper, we summarize the results of some smaller liquid metal experiments devoted to various magnetic instabilities such as the helical and the azimuthal magnetorotational instability, the Tayler instability, and the different instabilities that appear in a magnetized spherical Couette flow. We conclude with an outlook on a large scale Tayler-Couette experiment using liquid sodium, and on the prospects to observe magnetically triggered ...

  15. Producing acoustic 'Frozen Waves': simulated experiments with diffraction/attenuation resistant beams in lossy media.

    Science.gov (United States)

    Prego-Borges, José L; Zamboni-Rached, Michel; Recami, Erasmo; Costa, Eduardo Tavares

    2014-08-01

    The so-called Localized Waves (LW), and the "Frozen Waves" (FW), have raised significant attention in the areas of Optics and Ultrasound, because of their surprising energy localization properties. The LWs resist the effects of diffraction for large distances, and possess an interesting self-reconstruction -self-healing- property (after obstacles with size smaller than the antenna's); while the FWs, a sub-class of LWs, offer the possibility of arbitrarily modeling the longitudinal field intensity pattern inside a prefixed interval, for instance 0⩽z⩽L, of the wave propagation axis. More specifically, the FWs are localized fields "at rest", that is, with a static envelope (within which only the carrier wave propagates), and can be endowed moreover with a high transverse localization. In this paper we investigate, by simulated experiments, various cases of generation of ultrasonic FW fields, with the frequency of f0=1 MHz in a water-like medium, taking account of the effects of attenuation. We present results of FWs for distances up to L=80 mm, in attenuating media with absorption coefficient α in the range 70⩽α⩽170 dB/m. Such simulated FW fields are constructed by using a procedure developed by us, via appropriate finite superpositions of monochromatic ultrasonic Bessel beams. We pay due attention to the selection of the FW parameters, constrained by the rather tight restrictions imposed by experimental Acoustics, as well as to some practical implications of the transducer design. The energy localization properties of the Frozen Waves can find application even in many medical apparatus, such as bistouries or acoustic tweezers, as well as for treatment of diseased tissues (in particular, for the destruction of tumor cells, without affecting the surrounding tissues; also for kidney stone shuttering, etc.).

  16. Determination of the easy axes of small ferromagnetic precipitates in a bulk material by combined magnetic force microscopy and electron backscatter diffraction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Batista, L., E-mail: leonardo.batista@izfp.fraunhofer.de [Fraunhofer Institute for Non-destructive Testing (IZFP), Campus E3 1, 66123 Saarbrücken (Germany); Rabe, U. [Fraunhofer Institute for Non-destructive Testing (IZFP), Campus E3 1, 66123 Saarbrücken (Germany); University of the Saarland, LZPQ, 66123 Saarbrücken (Germany); Hirsekorn, S. [Fraunhofer Institute for Non-destructive Testing (IZFP), Campus E3 1, 66123 Saarbrücken (Germany)

    2014-11-15

    A method to determine the magnetic easy axes of micro- and nanoscopic ferromagnetic precipitates embedded in a bulk material is proposed and applied to globular cementite (Fe{sub 3}C) embedded in a ferrite matrix. The method combines magnetic force microscopy (MFM) with electron backscattered diffraction (EBSD) measurements. Magnetic domain structures in globular and in lamellar cementite precipitates in unalloyed pearlitic steels were imaged using MFM. The domain structure of the precipitates was analyzed in dependency of their size, shape and crystallographic orientation. It was found that the magnetic moments of the cementite precipitates are highly geared to their crystalline axes. The combined MFM and EBSD studies allow the conclusion that the cementite easy direction of magnetization is the long [010] axis. For fine lamellae cementite the determination of their crystallographic orientations using electron diffraction techniques is very difficult. With the previous knowledge of the behavior of the domain structure in globular cementite, the crystalline orientations of the fine lamellae cementite can be estimated by simply observing the magnetic microstructures and the topographic profiles. - Highlights: • We develop a method to determine the easy axes of nanoscopic ferromagnetic precipitates in a matrix. • We combine the magnetic force microscopy and the electron backscatter diffraction techniques. • Globular and lamellar cementite (Fe{sub 3}C) precipitates are taken as examples. • MFM images revealed different orientations of the magnetic moments in cementite. • The cementite easy direction of magnetization is the long [010] axis.

  17. Magnetic Structure of Tb-Tm Alloys Studied by Neutron Diffraction

    DEFF Research Database (Denmark)

    Hansen, P.; Lebech, Bente

    1976-01-01

    Single crystals of Tb-Tm alloys with Tm contents of 12%, 40%, 55% and 65% were investigated by neutron diffractometry over the temperature range 4.2-300K. All these alloys order magnetically to a basal plane spiral below the Neel temperature. Below the Curie temperature the magnetic ordering of t...... is modulated along the c axis (CAM structure). Tb-Tm alloys have an inhomogeneous phase, where the spins associated with the Tb ions lie in the basal plane, while the spins associated with the Tm ions order along the c axis....

  18. Simultaneous structural and magnetic transitions in YFe{sub 4}Ge{sub 2} studied by neutron diffraction and magnetic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Schobinger-Papamantellos, P. E-mail: schobinger@kristall.erdw.ethz.ch; Rodriguez-Carvajal, J.; Andre, G.; Duong, N.P.; Buschow, K.H.J.; Toledano, P

    2001-10-01

    The magnetic behaviour of the tetragonal YFe{sub 4}Ge{sub 2} compound has been studied by neutron diffraction and bulk magnetisation measurements. Magnetic ordering occurs below T{sub N}=43.5 K simultaneously with a structural transition from tetragonal P4{sub 2}/mnm{yields}Pnnm to orthorhombic symmetry. Both transitions are of first order. The symmetry breaking is connected with primary displacive order parameters involving shifts of the Fe atoms. The Fe site splits into two sites in Pnnm, the shifts of the Fe atoms with respect to the tetragonal phase have opposite signs along the a (dilatation) and b (contraction) axes. This induces the symmetry breaking tensile strains. The planar canted antiferromagnetic arrangement with eight sublattices is the ground state associated with a magnetic energy involving isotropic exchange and anisotropic (relativistic) interactions. The magnetic structure is invariant under the magnetic space group P((2{sub 1})/(n')) ((2{sub 1})/(n')) ((2{sub 1})/(m')) (Sh{sub 58}{sup 399}). The moments of the two orbits have the same value. At 1.5 K the Fe moment equals 0.63(4) {mu}{sub B}/Fe atom. The YFe{sub 4}Ge{sub 2} magnetostructural phenomena are compared to the more complex analogue of the ErFe{sub 4}Ge{sub 2} compound. The structural and magnetic transitions are described phenomenologically within a Landau-Dzialoshinski approach which assumes a triggering mechanism, in which the spontaneous strain is triggered by the exchange contribution to the magnetic ordering.

  19. Diffractive stacks of metamaterial lattices with a complex unit cell: Self-consistent long-range bianisotropic interactions in experiment and theory

    Science.gov (United States)

    Kwadrin, Andrej; Koenderink, A. Femius

    2014-01-01

    Metasurfaces and metamaterials promise arbitrary rerouting of light using two-dimensional (2D) planar arrangements of electric and magnetic scatterers, respectively, 3D stacks built out of such 2D planes. An important problem is how to self-consistently model the response of these systems in a manner that retains dipole intuition yet does full justice to the self-consistent multiple scattering via near-field and far-field retarded interactions. We set up such a general model for metamaterial lattices of complex 2D unit cells of poly-atomic basis as well as allowing for stacking in a third dimension. In particular, each scatterer is quantified by a magnetoelectric polarizability tensor and Ewald lattice summation deals with all near-field and long-range retarded electric, magnetic, and magnetoelectric couplings self-consistently. We show in theory and experiment that grating diffraction orders of dilute split ring lattices with complex unit cells show a background-free signature of magnetic dipole response. For denser lattices experiment and theory show that complex unit cells can reduce the apparent effect of bianisotropy, i.e., the strong oblique-incidence handed response that was reported for simple split ring lattices. Finally, the method is applied to calculate transmission of finite stacks of lattices. Thereby our simple methodology allows us to trace the emergence of effective material constants when building a 3D metamaterial layer by layer, as well as facilitating the design of metasurfaces.

  20. Neutron diffraction study of the magnetic long-range order in Tb

    DEFF Research Database (Denmark)

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

    1967-01-01

    Like other heavy rare-earth metals, Tb exhibits a magnetic phase with a spiral structure. This appears within the temperature region from 216 to 226deg K between the ferromagnetic phase and the paramagnetic phase. The transition between ferromagnetic and spiral structure is of first order and imp...

  1. Experiences with making diffraction image data available: what metadata do we need to archive?

    Energy Technology Data Exchange (ETDEWEB)

    Kroon-Batenburg, Loes M. J., E-mail: l.m.j.kroon-batenburg@uu.nl [Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands); Helliwell, John R. [University of Manchester, Brunswick Street, Manchester M14 9PL (United Kingdom); Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands)

    2014-10-01

    A local raw ‘diffraction data images’ archive was made available and some data sets were retrieved and reprocessed, which led to analysis of the anomalous difference densities of two partially occupied Cl atoms in cisplatin as well as a re-evaluation of the resolution cutoff in these diffraction data. General questions on storing raw data are discussed. It is also demonstrated that often one needs unambiguous prior knowledge to read the (binary) detector format and the setup of goniometer geometries. Recently, the IUCr (International Union of Crystallography) initiated the formation of a Diffraction Data Deposition Working Group with the aim of developing standards for the representation of raw diffraction data associated with the publication of structural papers. Archiving of raw data serves several goals: to improve the record of science, to verify the reproducibility and to allow detailed checks of scientific data, safeguarding against fraud and to allow reanalysis with future improved techniques. A means of studying this issue is to submit exemplar publications with associated raw data and metadata. In a recent study of the binding of cisplatin and carboplatin to histidine in lysozyme crystals under several conditions, the possible effects of the equipment and X-ray diffraction data-processing software on the occupancies and B factors of the bound Pt compounds were compared. Initially, 35.3 GB of data were transferred from Manchester to Utrecht to be processed with EVAL. A detailed description and discussion of the availability of metadata was published in a paper that was linked to a local raw data archive at Utrecht University and also mirrored at the TARDIS raw diffraction data archive in Australia. By making these raw diffraction data sets available with the article, it is possible for the diffraction community to make their own evaluation. This led to one of the authors of XDS (K. Diederichs) to re-integrate the data from crystals that supposedly

  2. Prospective of ultradispersic magnetic particles in biological experiments in microgravity

    Science.gov (United States)

    Nechitailo, Galina S.; Kuznetsov, Anatoli; Malashin, S.

    All organisms on Earth use gravity for their lifecycles. Microgravity disturbs the lifecycles significantly: orientation ability is damaged, thermo and mass exchange processes are changed, adaptation mechanisms are destroyed. A recovering the normal life cycle of organism in future long-term mission requires an artificial gravity which is complicate and not realistic with present technologies. We propose to use a magnetic properties of the biological objects for recovering of the gravity-dependent biological processes in organism during space flight. Based on result of magnetic properties investigation in gravity-sensitive plant cells, we have prepared and carried out the experiments on space station MIR. For the experiments, Magnitogravistat device was designed and installed on the station. The aim of the experiment was to replace a gravity factor of plant with a magnetic factor. The magnetic effect is based on the fact, that a magnetic particle of V volume is under the force F=ΔæVHgradH in the magnetic gradient gradH, where Δæ is the difference between the magnetic susceptibility of particle and media. When the particles are placed into the cell, the cell can be managed by the magnetic field. In laboratory experiment the iron-carbon particles of 1-2 um with nanostructurised surface and high adsorption properties have been used. The particles can be suspended in water and adsorbed chemicals including cell metabolites. In strong magnetic field, the particles can be agglomerated and the liquid substrate can be replaced. The local magnetic field near the particles can influence on cell processes. The magnetic field causes a cell differentiation and can influence on cell proliferation. A new space experiment with magnetic particles is planned to get a knowledge on cell influence and to improve a cell metabolism.

  3. Utilizing broadband X-rays in a Bragg coherent X-ray diffraction imaging experiment

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Wonsuk; Liu, Wenjun; Harder, Ross; Xu, Ruqing; Fuoss, Paul H.; Hruszkewycz, Stephan O.

    2016-07-26

    A method is presented to simplify Bragg coherent X-ray diffraction imaging studies of complex heterogeneous crystalline materials with a two-stage screening/imaging process that utilizes polychromatic and monochromatic coherent X-rays and is compatible within situsample environments. Coherent white-beam diffraction is used to identify an individual crystal particle or grain that displays desired properties within a larger population. A three-dimensional reciprocal-space map suitable for diffraction imaging is then measured for the Bragg peak of interest using a monochromatic beam energy scan that requires no sample motion, thus simplifyingin situchamber design. This approach was demonstrated with Au nanoparticles and will enable, for example, individual grains in a polycrystalline material of specific orientation to be selected, then imaged in three dimensions while under load.

  4. Utilizing broadband X-rays in a Bragg coherent X-ray diffraction imaging experiment.

    Science.gov (United States)

    Cha, Wonsuk; Liu, Wenjun; Harder, Ross; Xu, Ruqing; Fuoss, Paul H; Hruszkewycz, Stephan O

    2016-09-01

    A method is presented to simplify Bragg coherent X-ray diffraction imaging studies of complex heterogeneous crystalline materials with a two-stage screening/imaging process that utilizes polychromatic and monochromatic coherent X-rays and is compatible with in situ sample environments. Coherent white-beam diffraction is used to identify an individual crystal particle or grain that displays desired properties within a larger population. A three-dimensional reciprocal-space map suitable for diffraction imaging is then measured for the Bragg peak of interest using a monochromatic beam energy scan that requires no sample motion, thus simplifying in situ chamber design. This approach was demonstrated with Au nanoparticles and will enable, for example, individual grains in a polycrystalline material of specific orientation to be selected, then imaged in three dimensions while under load.

  5. Design of a Compact Coaxial Magnetized Plasma Gun for Magnetic Bubble Expansion Experiments

    Science.gov (United States)

    2009-06-01

    COAXIAL MAGNETIZED PLASMA GUN FOR MAGNETIC BUBBLE EXPANSION EXPERIMENTS Y. Zhang1, A. G. Lynn1, S. C. Hsu2, M. Gilmore1, C... coaxial magnetized plasma gun and its associated hardware systems are discussed in detail. The plasma gun is used for experimental studies of...and coaxial plasma guns - which is the method employed in this work. The first coaxial plasma gun experiment was performed five decades ago by

  6. Six-axis multi-anvil press for high-pressure, high-temperature neutron diffraction experiments.

    Science.gov (United States)

    Sano-Furukawa, A; Hattori, T; Arima, H; Yamada, A; Tabata, S; Kondo, M; Nakamura, A; Kagi, H; Yagi, T

    2014-11-01

    We developed a six-axis multi-anvil press, ATSUHIME, for high-pressure and high-temperature in situ time-of-flight neutron powder diffraction experiments. The press has six orthogonally oriented hydraulic rams that operate individually to compress a cubic sample assembly. Experiments indicate that the press can generate pressures up to 9.3 GPa and temperatures up to 2000 K using a 6-6-type cell assembly, with available sample volume of about 50 mm(3). Using a 6-8-type cell assembly, the available conditions expand to 16 GPa and 1273 K. Because the six-axis press has no guide blocks, there is sufficient space around the sample to use the aperture for diffraction and place an incident slit, radial collimators, and a neutron imaging camera close to the sample. Combination of the six-axis press and the collimation devices realized high-quality diffraction pattern with no contamination from the heater or the sample container surrounding the sample. This press constitutes a new tool for using neutron diffraction to study the structures of crystals and liquids under high pressures and temperatures.

  7. Six-axis multi-anvil press for high-pressure, high-temperature neutron diffraction experiments

    Energy Technology Data Exchange (ETDEWEB)

    Sano-Furukawa, A., E-mail: sano.asami@jaea.go.jp; Hattori, T. [Quantum Beam Science Center, Japan Atomic Energy Agency, Ibaraki 319-1195 (Japan); J-PARC Center, Japan Atomic Energy Agency, Ibaraki 319-1195 (Japan); Arima, H. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Yamada, A. [The University of Shiga Prefecture, Shiga 522-8533 (Japan); Tabata, S.; Kondo, M.; Nakamura, A. [Sumitomo Heavy Industries Co., Ltd., Ehime 792-0001 (Japan); Kagi, H.; Yagi, T. [Geochemical Research Center, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan)

    2014-11-15

    We developed a six-axis multi-anvil press, ATSUHIME, for high-pressure and high-temperature in situ time-of-flight neutron powder diffraction experiments. The press has six orthogonally oriented hydraulic rams that operate individually to compress a cubic sample assembly. Experiments indicate that the press can generate pressures up to 9.3 GPa and temperatures up to 2000 K using a 6-6-type cell assembly, with available sample volume of about 50 mm{sup 3}. Using a 6-8-type cell assembly, the available conditions expand to 16 GPa and 1273 K. Because the six-axis press has no guide blocks, there is sufficient space around the sample to use the aperture for diffraction and place an incident slit, radial collimators, and a neutron imaging camera close to the sample. Combination of the six-axis press and the collimation devices realized high-quality diffraction pattern with no contamination from the heater or the sample container surrounding the sample. This press constitutes a new tool for using neutron diffraction to study the structures of crystals and liquids under high pressures and temperatures.

  8. Introduction to Frustrated Magnetism Materials, Experiments, Theory

    CERN Document Server

    Lacroix, Claudine; Mila, Frédéric

    2011-01-01

    The field of Highly Frustrated Magnetism has developed and expanded considerably over the last 15 years. Originating with canonical geometric frustration of interactions, it today extends over other phenomena with many degrees of freedom, including magneto-elastic couplings, orbital degrees of freedom, dilution effects, and electron doping. It is also demonstrated that the concept of frustration impacts many other fields in physics beyond magnetism. This book represents a state-of-the-art review aimed at a broad audience with tutorial chapters and more topical ones, which encompass solid-state chemistry as well as experimental and theoretical physics.

  9. Self-calibrating phase measurement based on diffraction theory and numerical simulation experiments

    Science.gov (United States)

    Zhou, Liao; Qi, Qiu; Hao, Xian

    2015-02-01

    To achieve a full-aperture, diffraction-limited image, a telescope's segmented primary mirror must be properly phased. Furthermore, it is crucial to detect the piston errors between individual segments with high accuracy. Based on the diffraction imaging theory, the symmetrically shaped aperture with an arbitrarily positioned entrance pupil would focus at the optical axis with a symmetrical diffraction pattern. By selecting a single mirror as a reference mirror and regarding the diffraction image's center as the calibration point, a function can be derived that expresses the relationship between the piston error and the distance from the center of the inference image to the calibration point is linearity within one-half wavelength. These theoretical results are shown to be consistent with the results of a numerical simulation. Using this method, not only the piston error, but also the tip-tilt error can be detected. This method is simple and effective; it yields high-accuracy measurements and requires less computation time.

  10. How Rosalind Franklin Discovered the Helical Structure of DNA: Experiments in Diffraction

    Science.gov (United States)

    Braun, Gregory; Tierney, Dennis; Schmitzer, Heidrun

    2011-01-01

    Rosalind Franklin, a chemical physicist (1920-1958), used x-ray diffraction to determine the structure of DNA. What exactly could she read out from her x-ray pattern, shown in Fig. 1? In lecture notes dated November 1951, R. Franklin wrote the following: "The results suggest a helical structure (which must be very closely packed) containing 2, 3…

  11. Simple Experiments on Magnetism and Electricity...from Edison.

    Science.gov (United States)

    Schultz, Robert F.

    Background information, lists of materials needed and procedures used are provided for 16 simple experiments on electricity and magnetism. These experiments are organized into sections dealing with: (1) Edison's carbon experiments (building a galvanometer, investigating the variable conductivity of carbon, and examining the carbon transmitter…

  12. Experiences with making diffraction image data available: what metadata do we need to archive?

    Science.gov (United States)

    Kroon-Batenburg, Loes M J; Helliwell, John R

    2014-10-01

    Recently, the IUCr (International Union of Crystallography) initiated the formation of a Diffraction Data Deposition Working Group with the aim of developing standards for the representation of raw diffraction data associated with the publication of structural papers. Archiving of raw data serves several goals: to improve the record of science, to verify the reproducibility and to allow detailed checks of scientific data, safeguarding against fraud and to allow reanalysis with future improved techniques. A means of studying this issue is to submit exemplar publications with associated raw data and metadata. In a recent study of the binding of cisplatin and carboplatin to histidine in lysozyme crystals under several conditions, the possible effects of the equipment and X-ray diffraction data-processing software on the occupancies and B factors of the bound Pt compounds were compared. Initially, 35.3 GB of data were transferred from Manchester to Utrecht to be processed with EVAL. A detailed description and discussion of the availability of metadata was published in a paper that was linked to a local raw data archive at Utrecht University and also mirrored at the TARDIS raw diffraction data archive in Australia. By making these raw diffraction data sets available with the article, it is possible for the diffraction community to make their own evaluation. This led to one of the authors of XDS (K. Diederichs) to re-integrate the data from crystals that supposedly solely contained bound carboplatin, resulting in the analysis of partially occupied chlorine anomalous electron densities near the Pt-binding sites and the use of several criteria to more carefully assess the diffraction resolution limit. General arguments for archiving raw data, the possibilities of doing so and the requirement of resources are discussed. The problems associated with a partially unknown experimental setup, which preferably should be available as metadata, is discussed. Current thoughts on

  13. Change in the magnetic structure of (Bi,Sm)FeO{sub 3} thin films at the morphotropic phase boundary probed by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, Shingo; Anbusathaiah, Varatharajan; Takeuchi, Ichiro [Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742 (United States); Fennell, Amy [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Enderle, Mechthild [Institut Laue Langevin, BP 156, 38042 Grenoble (France); Ratcliff, William D., E-mail: william.ratcliff@nist.gov [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

    2014-11-01

    We report on the evolution of the magnetic structure of BiFeO{sub 3} thin films grown on SrTiO{sub 3} substrates as a function of Sm doping. We determined the magnetic structure using neutron diffraction. We found that as Sm increases, the magnetic structure evolves from a cycloid to a G-type antiferromagnet at the morphotropic phase boundary, where there is a large piezoelectric response due to an electric-field induced structural transition. The occurrence of the magnetic structural transition at the morphotropic phase boundary offers another route towards room temperature multiferroic devices.

  14. Change in the magnetic structure of (Bi,SmFeO3 thin films at the morphotropic phase boundary probed by neutron diffraction

    Directory of Open Access Journals (Sweden)

    Shingo Maruyama

    2014-11-01

    Full Text Available We report on the evolution of the magnetic structure of BiFeO3 thin films grown on SrTiO3 substrates as a function of Sm doping. We determined the magnetic structure using neutron diffraction. We found that as Sm increases, the magnetic structure evolves from a cycloid to a G-type antiferromagnet at the morphotropic phase boundary, where there is a large piezoelectric response due to an electric-field induced structural transition. The occurrence of the magnetic structural transition at the morphotropic phase boundary offers another route towards room temperature multiferroic devices.

  15. Spin and diffractive physics with A Fixed-Target ExpeRiment at the LHC (AFTER@LHC)

    CERN Document Server

    Lorce, C; Arnaldi, R; Brodsky, S J; Chambert, V; Didelez, J P; Ferreiro, E G; Fleuret, F; Genolini, B; Hadjidakis, C; Lansberg, J P; Rakotozafindrabe, A; Rosier, P; Schienbein, I; Scomparin, E; Uggerhoj, U I

    2012-01-01

    We report on the spin and diffractive physics at a future multi-purpose fixed-target experiment with proton and lead LHC beams extracted by a bent crystal. The LHC multi-TeV beams allow for the most energetic fixed-target experiments ever performed, opening new domains of particle and nuclear physics and complementing that of collider physics, in particular that of RHIC and the EIC projects. The luminosity achievable with AFTER using typical targets would surpass that of RHIC by more than 3 orders of magnitude. The fixed-target mode has the advantage to allow for measurements of single-spin asymmetries with polarized target as well as of single-diffractive processes in the target region.

  16. Crystal structure and magnetism of YbFeMnO 5: A neutron diffraction and Mössbauer spectroscopy study

    Science.gov (United States)

    Martínez-Lope, M. J.; Retuerto, M.; Alonso, J. A.; García-Hernández, M.; Krezhov, K.; Spirov, I.; Ruskov, T.; Fernández-Díaz, M. T.

    2009-04-01

    We have studied the crystal structure and magnetic properties of Y bFeMnO 5 obtained by substituting Fe 3+ for Mn 3+ in the parent Y bMn 2O 5 compound, through x-ray (XRD) and neutron (NPD) powder diffraction, magnetometry and Mössbauer spectroscopy. The samples were prepared in polycrystalline form by a soft chemistry route, followed by thermal treatments under high-oxygen pressure. The Rietveld analysis of diffraction data shows that Y bFeMnO 5 is isostructural with the oxides of stoichiometry RMn 2O 5 (R=rare earth, Y or Bi); the crystal structure is orthorhombic, Pbam space group, formed by chains of edge-sharing Mn 4+O 6 octahedra linked together by dimer groups of square pyramids Fe 3+O 5 and Y b 3+O 8 scalenohedra. A low level of disorder was established between the two transition metal positions 4 f and 4 h, occupied ideally by Mn 4+ and by Fe 3+: about 6% of Mn cations is replaced by Fe and 16% of Fe by Mn. Mössbauer spectroscopy data confirm the existence of two distinct crystallographic sites for Fe 3+. One of them corresponds to almost regular octahedra (at 4 f positions), characterized by nearly equal Mn/Fe-O distances of 1.890 Å at RT (from NPD data), giving a quadrupole doublet in the Mössbauer spectra at RT, broadened by the Fe/Mn disorder over this site. The second environment for Fe 3+ contributes to a less broadened, but more intensive doublet in the Mössbauer spectra, which corresponds to a distorted square pyramid Fe 3+O 5 (at 4h sites), for which NPD data demonstrates an axial distortion with three sets of Fe-O distances at 2.010(2) Å, 1.859(5) Å and 1.925(3) Å. Magnetic studies and the thermal evolution of the NPD patterns show that below a transition temperature Tc˜178 K a long-range magnetic order is developed, resolved from NPD data as a ferrimagnetic structure with propagation vector k=0. The spin arrangements for the Mn 4+ ions ( 4f site) and Fe 3+ ions ( 4h site) are given by the basis vectors ( 0,0,Fz) and ( 0,0,Fz

  17. An ultrahigh-vacuum apparatus for resonant diffraction experiments using soft x rays (hnu=300-2000 eV).

    Science.gov (United States)

    Takeuchi, T; Chainani, A; Takata, Y; Tanaka, Y; Oura, M; Tsubota, M; Senba, Y; Ohashi, H; Mochiku, T; Hirata, K; Shin, S

    2009-02-01

    We have developed an ultrahigh-vacuum instrument for resonant diffraction experiments using polarized soft x rays in the energy range of hnu=300-2000 eV at beamline BL17SU of SPring-8. The diffractometer consists of modified differentially pumped rotary feedthroughs for theta-2theta stages, a sample manipulator with motor-controlled x-y-z-, tilt (chi)-, and azimuth (phi)-axes, and a liquid helium flow-type cryostat for temperature dependent measurements between 30 and 300 K. Test results indicate that the diffractometer exhibits high reproducibility (better than 0.001 degrees ) for a Bragg reflection of alpha-quartz 100 at a photon energy of hnu=1950 eV. Typical off- and on-resonance Bragg reflections in the energy range of 530-1950 eV could be measured using the apparatus. The results show that x-ray diffraction experiments with energy-, azimuth-, and incident photon polarization-dependence can be reliably measured using soft x rays in the energy range of approximately 300-2000 eV. The facility can be used for resonant diffraction experiments across the L-edge of transition metals, M-edge of lanthanides, and up to the Si K-edge of materials.

  18. Neutron-diffraction studies of the nuclear magnetic phase diagram of copper

    DEFF Research Database (Denmark)

    Annila, A.J.; Clausen, Kurt Nørgaard; Oja, A.S.

    1992-01-01

    investigated by measuring the magnetic-field dependence of the (100) reflection, characteristic of a type-I AF structure, and of a Bragg peak at (0 2/3 2/3). The results suggest the presence of high-field (100) phases at 0.12 less-than-or-equal-to B less-than-or-equal-to B(c) almost-equal-to 0.26 mT, for B...... compared with results of earlier susceptibility measurements in order to identify the translational periods of the three previously found antiferromagnetic phases for B parallel-to [100]. Recent theoretical work has yielded results in agreement with our experimental data....

  19. Low-energy electron diffraction experiment, theory and surface structure determination

    CERN Document Server

    Hove, Michel A; Chan, Chi-Ming

    1986-01-01

    Surface crystallography plays the same fundamental role in surface science which bulk crystallography has played so successfully in solid-state physics and chemistry. The atomic-scale structure is one of the most important aspects in the understanding of the behavior of surfaces in such widely diverse fields as heterogeneous catalysis, microelectronics, adhesion, lubrication, cor­ rosion, coatings, and solid-solid and solid-liquid interfaces. Low-Energy Electron Diffraction or LEED has become the prime tech­ nique used to determine atomic locations at surfaces. On one hand, LEED has yielded the most numerous and complete structural results to date (almost 200 structures), while on the other, LEED has been regarded as the "technique to beat" by a variety of other surface crystallographic methods, such as photoemission, SEXAFS, ion scattering and atomic diffraction. Although these other approaches have had impressive successes, LEED has remained the most productive technique and has shown the most versatility...

  20. Operational experience with forced cooled superconducting magnets

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, D.P., E-mail: denis.ivanov30@mail.ru [National Research Center “Kurchatov Institute”, Moscow 123182 (Russian Federation); Kolbasov, B.N., E-mail: kolbasov@nfi.kiae.ru [National Research Center “Kurchatov Institute”, Moscow 123182 (Russian Federation); Anashkin, I.O.; Khvostenko, P.P. [National Research Center “Kurchatov Institute”, Moscow 123182 (Russian Federation); Pan, W.J. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, Anhui 230031 (China); Pradhan, S.; Sharma, A.N. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India); Song, Y.T.; Weng, P.D. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, Anhui 230031 (China)

    2013-10-15

    Highlights: ► Seventeen breakdowns happened in the fusion facilities with forced cooled superconducting magnets (FCSMs). ► The breakdowns always began on the electric, cryogenic and diagnostic communications (ECDCs) and never on the coils. ► In all the FCSMs the ECDCs were always insulated worse than the coils. ► For reliable operation of ITER organization team should essentially improve the ECDC insulation. ► Use of stainless steel grounded casings filled up with solid insulation over all the ECDCs is the best way to get reliable insulation. -- Abstract: Force-cooled concept has been chosen for ITER superconducting magnet to get reliable coil insulation using vacuum-pressure impregnation (VPI) technology. However 17 breakdowns occurred during operation of six magnets of this type or their single coil tests at operating voltage < 3 kV, while ITER needs 12 kV. All the breakdowns started on electric, cryogenic and diagnostic communications (ECDCs) by the high voltage induced at fast current variations in magnets concurrently with vacuum deterioration, but never on the coils, though sometimes the latter were damaged too. It suggests that simple wrap insulation currently employed on ECDCs and planned to be used in ITER is unacceptable. Upgrade of the ECDC insulation to the same level as on the coils is evidently needed. This could be done by covering each one from ECDCs with vacuum-tight grounded stainless steel casings filled up with solid insulator using VPI-technology. Such an insulation will be insensitive to in-cryostat conditions, excluding helium leaks and considerably simplifying the tests thus allowing saving time and cost. However it is not accepted in ITER design yet. So guarantee of breakdown prevention is not available.

  1. Novel Pr-Cu magnetic phase at low temperature in PrBa2Cu3O6+x observed by neutron diffraction

    DEFF Research Database (Denmark)

    Boothroyd, A.T.; Longmore, A.; Andersen, N.H.

    1997-01-01

    We have studied by neutron diffraction the magnetic ordering in Al-free crystals of PrBa2Cu3O6+x (x = 0.35 and 0.92) that do not display the AFII Cu magnetic phase. Wt find that the Pr ordering below 20 K is accompanied by a counterrotation of the Cu antiferromagnetism on each plane of the bilaye...

  2. The photoelectric effect and study of the diffraction of light: Two new experiments in UNILabs virtual and remote laboratories network

    Science.gov (United States)

    Pedro Sánchez, Juan; Sáenz, Jacobo; de la Torre, Luis; Carreras, Carmen; Yuste, Manuel; Heradio, Rubén; Dormido, Sebastián

    2016-05-01

    This work describes two experiments: "study of the diffraction of light: Fraunhofer approximation" and "the photoelectric effect". Both of them count with a virtual, simulated, version of the experiment as well as with a real one which can be operated remotely. The two previous virtual and remote labs (built using Easy Java(script) Simulations) are integrated in UNILabs, a network of online interactive laboratories based on the free Learning Management System Moodle. In this web environment, students can find not only the virtual and remote labs but also manuals with related theory, the user interface description for each application, and so on.

  3. Modeling HEDLA magnetic field generation experiments on laser facilities

    Science.gov (United States)

    Fatenejad, M.; Bell, A. R.; Benuzzi-Mounaix, A.; Crowston, R.; Drake, R. P.; Flocke, N.; Gregori, G.; Koenig, M.; Krauland, C.; Lamb, D.; Lee, D.; Marques, J. R.; Meinecke, J.; Miniati, F.; Murphy, C. D.; Park, H.-S.; Pelka, A.; Ravasio, A.; Remington, B.; Reville, B.; Scopatz, A.; Tzeferacos, P.; Weide, K.; Woolsey, N.; Young, R.; Yurchak, R.

    2013-03-01

    The Flash Center is engaged in a collaboration to simulate laser driven experiments aimed at understanding the generation and amplification of cosmological magnetic fields using the FLASH code. In these experiments a laser illuminates a solid plastic or graphite target launching an asymmetric blast wave into a chamber which contains either Helium or Argon at millibar pressures. Induction coils placed several centimeters away from the target detect large scale magnetic fields on the order of tens to hundreds of Gauss. The time dependence of the magnetic field is consistent with generation via the Biermann battery mechanism near the blast wave. Attempts to perform simulations of these experiments using the FLASH code have uncovered previously unreported numerical difficulties in modeling the Biermann battery mechanism near shock waves which can lead to the production of large non-physical magnetic fields. We report on these difficulties and offer a potential solution.

  4. Superconducting dipole magnet for the CBM experiment at FAIR

    Directory of Open Access Journals (Sweden)

    Kurilkin P.

    2017-01-01

    Full Text Available The scientific goal of the CBM (Compressed Baryonic Matter experiment at FAIR (Darmstadt is to explore the phase diagram of strongly interacting matter at highest baryon densities. The physics program of the CBM experiment is complimentary to the programs to be realized at MPD and BMN facilities at NICA and will start with beam derived by the SIS100 synchrotron. The 5.15 MJ superconducting dipole magnet will be used in the silicon tracking system of the CBM detector. The magnet will provide a magnetic field integral of 1 Tm which is required to obtain a momentum resolution of 1% for the track reconstruction. The results of the development of dipole magnet of the CBM experiment are presented.

  5. Enhancement of the steady-state magnetization in TROSY experiments

    Energy Technology Data Exchange (ETDEWEB)

    Riek, Roland [Institut fuer Molekularbiologie und Biophysik Eidgenoessische Technische Hochschule Hoenggerberg (Switzerland)], E-mail: rr@mol.biol.ethz.ch

    2001-10-15

    Under the condition that the longitudinal relaxation time of spin I is shorter than the longitudinal relaxation time of spin S the steady-state magnetization in [S,I]-TROSY-type experiments can be enhanced by intermediate storage of a part of the steady-state magnetization of spin I on spin S with a pulse sequence element during the relaxation delay. It is demonstrated with samples ranging in size from the 1 kDa cyclosporin to the 110 kDa {sup 15}N,{sup 2}H-labeled dihydroneopterin Aldolase that intermediate storage of steady-state magnetization in a [{sup 15}N,{sup 1}H]-TROSY experiment yields a signal gain of 10-25%. The method proposed here for intermediate storage of steady-state magnetization can be implemented in any [{sup 15}N,{sup 1}H]-TROSY-type experiments.

  6. Experimental magnetic form factors in Co3V2O8 : A combined study of ab initio calculations, magnetic Compton scattering, and polarized neutron diffraction

    Science.gov (United States)

    Qureshi, N.; Zbiri, M.; Rodríguez-Carvajal, J.; Stunault, A.; Ressouche, E.; Hansen, T. C.; Fernández-Díaz, M. T.; Johnson, M. R.; Fuess, H.; Ehrenberg, H.; Sakurai, Y.; Itou, M.; Gillon, B.; Wolf, Th.; Rodríguez-Velamazan, J. A.; Sánchez-Montero, J.

    2009-03-01

    We present a combination of ab initio calculations, magnetic Compton scattering, and polarized neutron experiments, which elucidate the density distribution of unpaired electrons in the kagome staircase system Co3V2O8 . Ab initio wave functions were used to calculate the spin densities in real and momentum spaces, which show good agreement with the respective experiments. It has been found that the spin polarized orbitals are equally distributed between the t2g and the eg levels for the spine (s) Co ions while the eg orbitals of the cross-tie (c) Co ions only represent 30% of the atomic spin density. Furthermore, the results reveal that the magnetic moments of the cross-tie Co ions, which are significantly smaller than those of the spine Co ions in the zero-field ferromagnetic structure, do not saturate by applying an external magnetic field of 2 T along the easy axis a . In turn, the increasing bulk magnetization, which can be observed by field dependent macroscopic measurements, originates from induced magnetic moments on the O and V sites. The refined individual magnetic moments are μ(Coc)=1.54(4)μB , μ(Cos)=2.87(3)μB , μ(V)=0.41(4)μB , μ(O1)=0.05(5)μB , μ(O2)=0.35(5)μB , and μ(O3)=0.36(5)μB combining to the same macroscopic magnetization value, which was previously only attributed to the Co ions.

  7. Structural and magnetic properties of inverse opal photonic crystals studied by x-ray diffraction, scanning electron microscopy, and small-angle neutron scattering

    NARCIS (Netherlands)

    Grigoriev, S.V.; Napolskii, K.S.; Grigoryeva, N.A.; Vasilieva, A.V.; Mistonov, A.A.; Chernyshov, D.Y.; Petukhov, A.V.; Belov, D.V.; Eliseev, A.A.; Lukashin, A.V.; Tretyakov, Y.D.; Sinitskii, A.S.; Eckerlebe, H.

    2009-01-01

    The structural and magnetic properties of nickel inverse opal photonic crystal have been studied by complementary experimental techniques, including scanning electron microscopy, wide-angle and small-angle diffraction of synchrotron radiation, and polarized neutrons. The sample was fabricated by ele

  8. Diffractive production of mesons

    CERN Document Server

    Schicker, R

    2014-01-01

    The interest in the study of diffractive meson production is discussed. The description of diffraction within Regge phenomenology is presented, and the QCD-based understanding of diffractive processes is given. Central production is reviewed, and the corresponding main results from the COMPASS experiment and from the experiments at the ISR, RHIC, TEVATRON and LHC collider are summarised.

  9. Diffractive production of mesons

    Directory of Open Access Journals (Sweden)

    Schicker Rainer

    2014-01-01

    Full Text Available The interest in the study of diffractive meson production is discussed. The description of diffraction within Regge phenomenology is presented, and the QCD-based understanding of diffractive processes is given. Central production is reviewed, and the corresponding main results from the COMPASS experiment and from the experiments at the ISR, RHIC, TEVATRON and LHC collider are summarised.

  10. Lattice thermal expansion and anisotropic displacements in 𝜶-sulfur from diffraction experiments and first-principles theory

    Science.gov (United States)

    George, Janine; Deringer, Volker L.; Wang, Ai; Müller, Paul; Englert, Ulli; Dronskowski, Richard

    2016-12-01

    Thermal properties of solid-state materials are a fundamental topic of study with important practical implications. For example, anisotropic displacement parameters (ADPs) are routinely used in physics, chemistry, and crystallography to quantify the thermal motion of atoms in crystals. ADPs are commonly derived from diffraction experiments, but recent developments have also enabled their first-principles prediction using periodic density-functional theory (DFT). Here, we combine experiments and dispersion-corrected DFT to quantify lattice thermal expansion and ADPs in crystalline α-sulfur (S8), a prototypical elemental solid that is controlled by the interplay of covalent and van der Waals interactions. We begin by reporting on single-crystal and powder X-ray diffraction measurements that provide new and improved reference data from 10 K up to room temperature. We then use several popular dispersion-corrected DFT methods to predict vibrational and thermal properties of α-sulfur, including the anisotropic lattice thermal expansion. Hereafter, ADPs are derived in the commonly used harmonic approximation (in the computed zero-Kelvin structure) and also in the quasi-harmonic approximation (QHA) which takes the predicted lattice thermal expansion into account. At the PPBE+D3(BJ) level, the QHA leads to excellent agreement with experiments. Finally, more general implications of this study for theory and experiment are discussed.

  11. Proton-proton collisions at the Large Hadron Collider's ALICE Experiment: diffraction and high multiplicity

    CERN Document Server

    Matthews, Zoe Louise

    Diffraction in pp collisions contributes approximately 30 % of the inelastic cross section. Its influence on the pseudorapidity density is not well constrained at high energy. A method to estimate the contributing fractions of diffractive events to the inelastic cross section has been developed, and the fractions are measured in the ALICE detector at 900 GeV (7 TeV) to be f_D=0.278\\pm0.055 (f_D=0.28\\pm0.054) respectively. These results are compatible with recent ATLAS and ALICE measurements. Bjorken’s energy density relation suggests that, in high multiplicity pp collisions at the LHC, an environment comparable to A-A collisions at RHIC could be produced. Such events are of great interest to the ALICE Collaboration. Constraints on the running conditions have been established for obtaining a high multiplicity pp data sample using the ALICE detector’s multiplicity trigger. A model independent method to separate a multiplicity distribution from ‘pile-up’ contributions has been developed, and used in conn...

  12. Diffractive processes in pp collisions at 7 TeV measured with the CMS experiment

    CERN Document Server

    Brona, Grzegorz Konrad

    2015-01-01

    The differential diffractive cross section is measured as a function of $\\xi= M_X^2/s$ in the region dominated by single dissociation (SD) and double dissociation (DD), where $M_X$ is the mass of one of the two final-state hadronic systems separated by the largest rapidity gap in the event. The cross section is also measured as a function of the width of the central rapidity gap in the region dominated by DD, as well as for events with a forward gap over 8.4 units of pseudorapidity. The total SD and DD cross sections are extracted. Single diffraction is one of the main uncertainties both, experimentally and in theoretical calculations, of the particle-production cross section in proton-lead collisions as measured at the centre-of-mass energy per nucleon pair of 5.02 TeV. Furthermore, the observation of a hard color-singlet exchange process in events with a large rapidity gap between two leading jets (jet-gap-jet) is reported. The fraction of jet-gap-jet to all dijet events is measured as a function of the sec...

  13. Crystallization and preliminary neutron diffraction experiment of human farnesyl pyrophosphate synthase complexed with risedronate.

    Science.gov (United States)

    Yokoyama, Takeshi; Ostermann, Andreas; Mizuguchi, Mineyuki; Niimura, Nobuo; Schrader, Tobias E; Tanaka, Ichiro

    2014-04-01

    Nitrogen-containing bisphosphonates (N-BPs), such as risedronate and zoledronate, are currently used as a clinical drug for bone-resorption diseases and are potent inhibitors of farnesyl pyrophosphate synthase (FPPS). X-ray crystallographic analyses of FPPS with N-BPs have revealed that N-BPs bind to FPPS with three magnesium ions and several water molecules. To understand the structural characteristics of N-BPs bound to FPPS, including H atoms and hydration by water, neutron diffraction studies were initiated using BIODIFF at the Heinz Maier-Leibnitz Zentrum (MLZ). FPPS-risedronate complex crystals of approximate dimensions 2.8 × 2.5 × 1.5 mm (∼3.5 mm(3)) were obtained by repeated macro-seeding. Monochromatic neutron diffraction data were collected to 2.4 Å resolution with 98.4% overall completeness. Here, the first successful neutron data collection from FPPS in complex with N-BPs is reported.

  14. Crystallization and preliminary X-ray diffraction experiments of arylmalonate decarboxylase from Alcaligenes bronchisepticus

    Energy Technology Data Exchange (ETDEWEB)

    Nakasako, Masayoshi, E-mail: nakasako@phys.keio.ac.jp [Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Kanagawa 223-8522 (Japan); The RIKEN Harima Institute/SPring-8, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan); Obata, Rika; Okubo, Ryosuke; Nakayama, Shyuichi [Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Kanagawa 223-8522 (Japan); Miyamoto, Kenji; Ohta, Hiromichi [Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Kanagawa 223-8522 (Japan); Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Kanagawa 223-8522 (Japan)

    2008-07-01

    Crystals of arylmalonate decarboxylase from A. bronchisepticus were obtained which diffracted X-rays to a resolution of at least 3.0 Å. Arylmalonate decarboxylase catalyses the enantioselective decarboxylation of α-aryl-α-methylmalonates to produce optically pure α-arylpropionates. The enzyme was crystallized with ammonium sulfate under alkaline pH conditions with the aim of understanding the mechanism of the enantioselective reaction. X-ray diffraction data collected to a resolution of 3.0 Å at cryogenic temperature showed that the crystals belonged to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 83.13, b = 99.62, c = 139.64 Å. This suggested that the asymmetric unit would contain between four and six molecules. Small-angle X-ray scattering revealed that the enzyme exists as a monomer in solution. Thus, the assembly of molecules in the asymmetric unit was likely to have been induced during the crystallization process.

  15. Magnetized and Flat Beam Experiment at FAST

    Energy Technology Data Exchange (ETDEWEB)

    Halavanau, A. [Fermilab; Hyun, J. [Sokendai, Tsukuba; Mihalcea, D. [NIU, DeKalb; Piot, P. [NICADD, DeKalb; Sen, T. [Fermilab; Thangaraj, C. [Fermilab

    2017-05-22

    A photocathode, immersed in solenoidal magnetic field, can produce canonical-angular-momentum (CAM) dominated or “magnetized” electron beams. Such beams have an application in electron cooling of hadron beams and can also be uncoupled to yield asymmetric-emittance (“flat”) beams. In the present paper we explore the possibilities of the flat beam generation at Fermilab’s Accelerator Science and Technology (FAST) facility. We present optimization of the beam flatness and four-dimensional transverse emittance and investigate the mapping and its limitations of the produced eigen-emittances to conventional emittances using a skew-quadrupole channel. Possible application of flat beams at the FAST facility are also discussed.

  16. Magnetic properties of ferromagnetic nanowire arrays: Theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Ghaddar, A; Gieraltowski, J [Laboratoire de Magnetisme de Bretagne, UBO, CNRS-FRE 3117, C. S. 93837 Brest Cedex 3 (France); Gloaguen, F, E-mail: abbas.ghaddar@univ-brest.f [Laboratoire de Chimie, Electrochimie Moleculaire et Chimie Analytique, UBO, CNRS-UMR 6521, C. S. 93837 Brest Cedex 3 (France)

    2010-01-01

    Magnetic nanowires are good candidates for microwave filters, sensors and data storage applications. An investigation of magnetic properties of single-component nanowires as a function of diameter and aspect ratio is performed in this work. Nickel nanowire (with 15 and 100 nm diameter and 6000 nm length) are grown with electrodeposition in polycarbonates templates. Two reversal modes (coherent and curling) are studied versus nanowire diameter. Magnetostatic interaction among wires and its effect on nanowire magnetic properties is also studied. Using vibrating magnetometer (VSM) and X-band ferromagnetic resonance (FMR) experiments at room temperature we infer that the interaction field H{sub c} value may vary significantly and may cause a change of magnetic easy axis orientation along geometrical wire axis (for large diameter) to an easy magnetic plane perpendicular to the nanowire axis (for small diameter).

  17. Numerical Investigation of Plasma Detachment in Magnetic Nozzle Experiments

    Science.gov (United States)

    Sankaran, Kamesh; Polzin, Kurt A.

    2008-01-01

    At present there exists no generally accepted theoretical model that provides a consistent physical explanation of plasma detachment from an externally-imposed magnetic nozzle. To make progress towards that end, simulation of plasma flow in the magnetic nozzle of an arcjet experiment is performed using a multidimensional numerical simulation tool that includes theoretical models of the various dispersive and dissipative processes present in the plasma. This is an extension of the simulation tool employed in previous work by Sankaran et al. The aim is to compare the computational results with various proposed magnetic nozzle detachment theories to develop an understanding of the physical mechanisms that cause detachment. An applied magnetic field topology is obtained using a magnetostatic field solver (see Fig. I), and this field is superimposed on the time-dependent magnetic field induced in the plasma to provide a self-consistent field description. The applied magnetic field and model geometry match those found in experiments by Kuriki and Okada. This geometry is modeled because there is a substantial amount of experimental data that can be compared to the computational results, allowing for validation of the model. In addition, comparison of the simulation results with the experimentally obtained plasma parameters will provide insight into the mechanisms that lead to plasma detachment, revealing how they scale with different input parameters. Further studies will focus on modeling literature experiments both for the purpose of additional code validation and to extract physical insight regarding the mechanisms driving detachment.

  18. HiSPoD: a program for high-speed polychromatic X-ray diffraction experiments and data analysis on polycrystalline samples.

    Science.gov (United States)

    Sun, Tao; Fezzaa, Kamel

    2016-07-01

    A high-speed X-ray diffraction technique was recently developed at the 32-ID-B beamline of the Advanced Photon Source for studying highly dynamic, yet non-repeatable and irreversible, materials processes. In experiments, the microstructure evolution in a single material event is probed by recording a series of diffraction patterns with extremely short exposure time and high frame rate. Owing to the limited flux in a short pulse and the polychromatic nature of the incident X-rays, analysis of the diffraction data is challenging. Here, HiSPoD, a stand-alone Matlab-based software for analyzing the polychromatic X-ray diffraction data from polycrystalline samples, is described. With HiSPoD, researchers are able to perform diffraction peak indexing, extraction of one-dimensional intensity profiles by integrating a two-dimensional diffraction pattern, and, more importantly, quantitative numerical simulations to obtain precise sample structure information.

  19. The instrumented magnets for the OPERA experiment construction and commissioning

    CERN Document Server

    Adinolfi Falcone, R; Cazes, A; Peiro, G

    2007-01-01

    The design and construction of the 990-ton gapless iron magnets for the OPERA experiment represent a major challenge from the point of view of mechanics, electric and heat engineering. Two of such magnets have been built in a deep underground hall of the Gran Sasso laboratories between 2003 and 2006 and they have been switched on for the first time in March 2006. In this paper we discuss the construction and characterization of these devices. First experience with the CNGS beam are also reported.

  20. Precise Magnetic Structures of Hard Ferromagnets of ND2FE14B Type as Determined at Low Temperature from Single Crystal Neutron Diffraction

    Science.gov (United States)

    Wolfers, P.; Bacmann, M.; Fruchart, D.

    2000-09-01

    The main constituent of the hard magnet materials Nd-Fe-B is the prototype of a new ferromagnet series, the Nd2Fe14B type (Space Group P42/nmm). Such compounds are characterised by high magnetocrystalline anisotropy parameters, those of rare earth origin being several times higher than the contribution of the iron subblattices. In many cases, these two contributions exhibit markedly different thermal behaviours, resulting in spin rotation phenomena or (and) lowering of the crystalline and the magnetic symmetry from the tetragonal high temperature state. Low temperature very precise studies on selected compounds of the series R2Fe14B with R = Nd, Ho, Er and Y, were undertaken by using neutron four circle diffractometry on single crystals. When temperature is lowered, the two first compounds exhibit a continuous spin reorientation within the [110] plane from the c-axis at high temperature towards an intermediate direction. The Er compound presents a first order transition around 350K where the resulting magnetisation first order rotates from the c-axis a high temperature to the a basal plane direction at low temperature. The last one compound remains c-easy axis in the whole temperature range. From our neutron diffraction experiments, lowering of the crystal symmetry to monoclinic (orthorhombic) space groups was precisely measured for the two first (third) samples. Besides marked deviations to collinearity affect the different sublattice magnetisations. Yet, these well marked phenomena have not been accounted for in the hundert experimental and theoretical analysis dedicated to the series. However, our results are in good agreement with a detailed 57Fe Mössbauer spectroscopy analysis of the Ho ternary hydrides.

  1. Precision magnetic field mapping for CERN experiment NA62

    Science.gov (United States)

    Fry, John R.; Ruggiero, Giuseppe; Bergsma, Felix

    2016-12-01

    In the CERN experiment NA62, low-mass straw-tube tracking-chambers have been designed to operate in vacuum and, in conjunction with precisely mapped magnetic fields, enable the determination of the trajectories of the charged decay products of a 75 GeV/c K+ with high accuracy. This is particularly important for the crucial measurement of the branching fraction for the decay K+ → π + ν ν, which has the potential to reveal BSM physics. The charged particles passing through the magnetic field of a dipole magnet receive a transverse-momentum kick, ΔP T = 270 MeV/c, which the physics requires to be determined to better than one part in a thousand. This puts stringent constraints on the required accuracy and precision of the magnetic field components at all points through which charged particles pass. Before reaching the dipole magnet the particles travel through an evacuated steel tank of length 90 m, where residual magnetic fields of typical size 50 μT modify the trajectories of the charged particles and require measurement with a precision of better than 10 μT. In this paper we describe in detail the different approaches to the measurement and analysis of the magnetic field for the two regions, the corrections to the raw data necessary to produce the final field map, and the physics validation procedures showing that the required accuracy and precision of the field maps have been achieved.

  2. [Development of RF coil of permanent magnet mini-magnetic resonance imager and mouse imaging experiments].

    Science.gov (United States)

    Hou, Shulian; Xie, Huantong; Chen, Wei; Wang, Guangxin; Zhao, Qiang; Li, Shiyu

    2014-10-01

    In the development of radio frequency (RF) coils for better quality of the mini-type permanent magnetic resonance imager for using in the small animal imaging, the solenoid RF coil has a special advantage for permanent magnetic system based on analyses of various types.of RF coils. However, it is not satisfied for imaging if the RF coils are directly used. By theoretical analyses of the magnetic field properties produced from the solenoid coil, the research direction was determined by careful studies to raise further the uniformity of the magnetic field coil, receiving coil sensitivity for signals and signal-to-noise ratio (SNR). The method had certain advantages and avoided some shortcomings of the other different coil types, such as, birdcage coil, saddle shaped coil and phased array coil by using the alloy materials (from our own patent). The RF coils were designed, developed and made for keeled applicable to permanent magnet-type magnetic resonance imager, multi-coil combination-type, single-channel overall RF receiving coil, and applied for a patent. Mounted on three instruments (25 mm aperture, with main magnetic field strength of 0.5 T or 1.5 T, and 50 mm aperture, with main magnetic field strength of 0.48 T), we performed experiments with mice, rats, and nude mice bearing tumors. The experimental results indicated that the RF receiving coil was fully applicable to the permanent magnet-type imaging system.

  3. Vacuum magnetic linear birefringence using pulsed fields: the BMV experiment

    CERN Document Server

    Cadène, A; Fouché, M; Battesti, R; Rizzo, C

    2013-01-01

    In this letter we present the measurement of the vacuum magnetic birefringence obtained using the first generation setup of the BMV experiment. In particular, we detail our procedure of data acquisition and our analysis which takes into account the symmetry properties of raw data with respect to the orientation of the magnetic field and the sign of the cavity birefringence. Our current value of vacuum magnetic linear birefringence k_CM was obtained with about 100 magnetic pulses and a maximum field of 6.5 T. We get k_CM = (-7.4 \\pm 8.7).10^{-21} T^{-2} at 3 sigma confidence level. Our result is a clear validation of our innovative experimental method.

  4. Development of a multipurpose vacuum chamber for serial optical and diffraction experiments with free electron laser radiation

    Energy Technology Data Exchange (ETDEWEB)

    Rajkovic, I.; Hallmann, J.; Gruebel, S.; More, R.; Quevedo, W.; Petri, M.; Techert, S. [Department of Structural Dynamics of (Bio)chemical Systems, Max Planck Institute for Biophysical Chemistry, 37070 Goettingen (Germany)

    2010-04-15

    In this paper we present a development of a multipurpose vacuum chamber which primal function is to be used in pump/probe experiments with free electron laser (FEL) radiation. The chamber is constructed for serial diffraction and serial spectroscopy allowing a fast exchange of samples during the measurement process. For the fast exchange of samples, liquid jet systems are used. Both applications, utilizing soft x-ray FEL pulses as pump and optical laser pulses as probe and vice versa are documented. Experiments with solid samples as well as the liquid jet samples are presented. When working with liquid jets, a system of automatically refilled liquid traps for capturing liquids has been developed in order to ensure stable vacuum conditions. Differential pumping stages are placed in between the FEL beamline and the experimental chamber so that working pressure in the chamber can be up to four orders of magnitude higher than the pressure in the FEL beamline.

  5. A 7 T Pulsed Magnetic Field Generator for Magnetized Laser Plasma Experiments

    Science.gov (United States)

    Hu, Guangyue; Liang, Yihan; Song, Falun; Yuan, Peng; Wang, Yulin; Zhao, Bin; Zheng, Jian

    2015-02-01

    A pulsed magnetic field generator was developed to study the effect of a magnetic field on the evolution of a laser-generated plasma. A 40 kV pulsed power system delivered a fast (~230 ns), 55 kA current pulse into a single-turn coil surrounding the laser target, using a capacitor bank of 200 nF, a laser-triggered switch and a low-impedance strip transmission line. A one-dimensional uniform 7 T pulsed magnetic field was created using a Helmholtz coil pair with a 6 mm diameter. The pulsed magnetic field was controlled to take effect synchronously with a nanosecond heating laser beam, a femtosecond probing laser beam and an optical Intensified Charge Coupled Device (ICCD) detector. The preliminary experiments demonstrate bifurcation and focusing of plasma expansion in a transverse magnetic field.

  6. A Unit Cell Laboratory Experiment: Marbles, Magnets, and Stacking Arrangements

    Science.gov (United States)

    Collins, David C.

    2011-01-01

    An undergraduate first-semester general chemistry laboratory experiment introducing face-centered, body-centered, and simple cubic unit cells is presented. Emphasis is placed on the stacking arrangement of solid spheres used to produce a particular unit cell. Marbles and spherical magnets are employed to prepare each stacking arrangement. Packing…

  7. Perspectives for nEDM Search by Crystal Diffraction. Test Experiment and Results

    Energy Technology Data Exchange (ETDEWEB)

    Fedorov, V.V. [Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg (Russian Federation); Jentschel, M. [Institute Laue-Langevin, Grenoble (France); Kuznetsov, I.A.; Lapin, E.G. [Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg (Russian Federation); Lelievre-Berna, E.; Nesvizhevsky, V.; Petoukhov, A. [Institute Laue-Langevin, Grenoble (France); Semenikhin, S.Yu. [Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg (Russian Federation); Soldner, T. [Institute Laue-Langevin, Grenoble (France); Voronin, V.V. [Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg (Russian Federation)], E-mail: vvv@pnpi.spb.ru; Braginetz, Yu.P. [Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg (Russian Federation)

    2009-08-15

    An experiment searching for the neutron electric dipole moment by measuring spin-rotations in a non-centrosymmetric crystal was carried out to investigate the statistical sensitivity and systematic effects of the method. The preliminary result of this experiment is d{sub n}=(2.5{+-}6.5).10{sup -24} e.cm. The performance was essentially limited by the low luminosity of the prototype setup. With a dedicated setup and a large quartz crystal, the expected accuracy is {approx}2.10{sup -26} e.cm for 100 days of data collection.

  8. X-Ray Diffraction of Intermetallic Compounds: A Physical Chemistry Laboratory Experiment

    Science.gov (United States)

    Varberg, Thomas D.; Skakuj, Kacper

    2015-01-01

    Here we describe an experiment for the undergraduate physical chemistry laboratory in which students synthesize the intermetallic compounds AlNi and AlNi3 and study them by X-ray diffractometry. The compounds are synthesized in a simple one-step reaction occurring in the solid state. Powder X-ray diffractograms are recorded for the two compounds…

  9. X-Ray Diffraction of Intermetallic Compounds: A Physical Chemistry Laboratory Experiment

    Science.gov (United States)

    Varberg, Thomas D.; Skakuj, Kacper

    2015-01-01

    Here we describe an experiment for the undergraduate physical chemistry laboratory in which students synthesize the intermetallic compounds AlNi and AlNi3 and study them by X-ray diffractometry. The compounds are synthesized in a simple one-step reaction occurring in the solid state. Powder X-ray diffractograms are recorded for the two compounds…

  10. Demonstration of thermonuclear conditions in Magnetized Liner Inertial Fusion experiments

    Science.gov (United States)

    Gomez, Matthew

    2014-10-01

    The Magnetized Liner Inertial Fusion concept utilizes a magnetic field and laser heating to relax the implosion requirements to achieve inertial confinement fusion. The first experiments to test the concept were recently conducted utilizing the 19 MA, 100 ns Z machine, the 2.5 kJ, 1 TW Z Beamlet laser, and the 10 T Applied B-field on Z coils. Despite the relatively slow implosion velocity (70 km/s) in these experiments, electron and ion temperatures at stagnation were approximately 3 keV, and thermonuclear DD neutron yields up to 2e12 have been produced. X-ray emission from the fuel at stagnation had a width ranging from 60-120 microns over a roughly 6 mm height and lasted approximately 2 ns. X-ray spectra from these experiments are consistent with a stagnation density of the hot fuel equal to 0.4 g/cm3 . In these experiments 1-5e10 secondary DT neutrons were produced. Given that the areal density of the plasma was approximately 2 mg/cm2, this indicates the stagnation plasma was significantly magnetized. This is consistent with the anisotropy observed in the DT neutron time of flight spectra. Control experiments where the laser and/or magnetic field were not utilized failed to produce stagnation temperatures greater than 1 keV and DD yields greater than 1e10. An additional control experiment where the fuel contained a sufficient dopant fraction to radiate away the laser energy deposited in the fuel also failed to produce a relevant stagnation temperature. The results of these experiments are consistent with a thermonuclear neutron source. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract No. DE-AC04-94AL85000.

  11. X-ray diffraction on MnFeP{sub 0.46}As{sub 0.54} in a magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Tegus, O. [Van der Waals-Zeeman Instituut, Universiteit van Amsterdam, 1018 XE Amsterdam (Netherlands)]. E-mail: tegus@science.uva.nl; Koyama, K. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Her, J.L. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Watanabe, K. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Brueck, E. [Van der Waals-Zeeman Instituut, Universiteit van Amsterdam, 1018 XE Amsterdam (Netherlands); Buschow, K.H.J. [Van der Waals-Zeeman Instituut, Universiteit van Amsterdam, 1018 XE Amsterdam (Netherlands); Boer, F.R. de [Van der Waals-Zeeman Instituut, Universiteit van Amsterdam, 1018 XE Amsterdam (Netherlands)

    2007-04-15

    We have performed powder X-ray-diffraction measurements on MnFeP{sub 0.46}As{sub 0.54} in fields up to 5T in the temperature range 8-310K. The compound which has the hexagonal Fe{sub 2}P type of structure shows a field-induced isostructural phase transition. We found that the cell volume decreases slightly and continuously with increasing magnetic field, although the lattice parameter ratio c/a drastically changes. A tentative analysis of the dependence of the lattice parameters on the magnetization has been carried out using the extended Bean-Rodbell model.

  12. Unsteady magnetic reconnection in laboratory experiments with current sheets

    Science.gov (United States)

    Frank, Anna

    2009-11-01

    According to present notion, unsteady magnetic reconnection in current sheets (CS) is basic to dramatic natural phenomena: solar and stellar flares, substorms in the Earth and other planetary magnetospheres, as well as to disruptive instabilities in tokamak plasmas. We present a review of laboratory experiments studying evolution of CS formed in 3D and 2D magnetic configurations with an X line, in the CS-3D device. Usually CS exists during an extended period in a metastable stage, without essential changes of its structure and parameters. Under certain conditions this stage may be suddenly interrupted by unsteady phase of magnetic reconnection, which manifests itself in a rapid change of the magnetic field topology, current redistribution, excitation of pulsed electric fields, and other dynamic effects. The unsteady phase results in effective conversion of magnetic energy into the energy of plasma and accelerated particles, and may finally bring about the CS disruption. In the context of the solar flares, a metastable CS is associated with a pre-flare situation, while CS disruption -- with the flare itself. The physical mechanisms triggering the unsteady magnetic reconnection in the laboratory produced current sheets are discussed. Supported by the Russian Foundation for Basic Research (project # 09-02-00971).

  13. Measurements of Long-range Electronic Correlations During Femtosecond Diffraction Experiments Performed on Nanocrystals of Buckminsterfullerene.

    Science.gov (United States)

    Ryan, Rebecca A; Williams, Sophie; Martin, Andrew V; Dilanian, Ruben A; Darmanin, Connie; Putkunz, Corey T; Wood, David; Streltsov, Victor A; Jones, Michael W M; Gaffney, Naylyn; Hofmann, Felix; Williams, Garth J; Boutet, Sebastien; Messerschmidt, Marc; Seibert, M Marvin; Curwood, Evan K; Balaur, Eugeniu; Peele, Andrew G; Nugent, Keith A; Quiney, Harry M; Abbey, Brian

    2017-08-22

    The precise details of the interaction of intense X-ray pulses with matter are a topic of intense interest to researchers attempting to interpret the results of femtosecond X-ray free electron laser (XFEL) experiments. An increasing number of experimental observations have shown that although nuclear motion can be negligible, given a short enough incident pulse duration, electronic motion cannot be ignored. The current and widely accepted models assume that although electrons undergo dynamics driven by interaction with the pulse, their motion could largely be considered 'random'. This would then allow the supposedly incoherent contribution from the electronic motion to be treated as a continuous background signal and thus ignored. The original aim of our experiment was to precisely measure the change in intensity of individual Bragg peaks, due to X-ray induced electronic damage in a model system, crystalline C60. Contrary to this expectation, we observed that at the highest X-ray intensities, the electron dynamics in C60 were in fact highly correlated, and over sufficiently long distances that the positions of the Bragg reflections are significantly altered. This paper describes in detail the methods and protocols used for these experiments, which were conducted both at the Linac Coherent Light Source (LCLS) and the Australian Synchrotron (AS) as well as the crystallographic approaches used to analyse the data.

  14. Crystallographic and magnetic structure in spinel system FeGa {sub x} Cr{sub 2-} {sub x} S{sub 4} by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Soon Son, Bae [Department of Physics, Kookmin University, Seoul 136-702 (Korea, Republic of); Jin Kim, Sam [Department of Physics, Kookmin University, Seoul 136-702 (Korea, Republic of); Shim, In-Bo [Department of Physics, Kookmin University, Seoul 136-702 (Korea, Republic of); Wha Lee, Bo [Department of Physics, Hankuk University of Foreign Studies, Yongin, Kyungki, 449-791 (Korea, Republic of); Sung Kim, Chul [Department of Physics, Kookmin University, Seoul 136-702 (Korea, Republic of)]. E-mail: cskim@phys.kookmin.ac.kr

    2006-09-15

    The samples of FeGa {sub x} Cr{sub 2-} {sub x} S{sub 4} (x=0.1, 0.3) were prepared by solid reaction method. The crystallographic structure and the magnetic properties of the obtained compounds were investigated by X-ray and neutron powder diffraction, vibrating sample magnetometer (VSM), and Moessbauer spectroscopy. The Cr ions occupy 16(d) site exclusively, while mixed spinel behaviors are developed with increase of Ga ions. Finally, it induces a large quadrupole splitting in octahedral (16d) sites. Neutron diffraction on FeGa {sub x} Cr{sub 2-} {sub x} S{sub 4} above 10 K shows that there is no crystallographic distortion and reveals antiferromagnetic ordering. The magnetic moment of Fe{sup 2+} (3.45 {mu} {sub B}) are found to be aligned antiparallel to Cr{sup 3+} (-2.89 {mu} {sub B}), in the sample x=0.1. Below the Neel temperature, magnetic peaks exist on the crystal diffraction peaks. It proves that spin structure of the same species are aligned parallel.

  15. 弱磁场中向列相液晶TEB30 A薄膜自衍射现象研究%Self-diffraction effect of nematic liquid TEB30A film in weak magnetic field

    Institute of Scientific and Technical Information of China (English)

    刘桂香; 王雁冰

    2016-01-01

    The far-field diffraction characteristics was studied in the different weak magnetic fields(0, 0.464 9,0.506 2 and 0.518 5 T)with the low power He-Ne laser of 1.5 mW(632.8 nm)being normal incident on the film of nematic liquid crystals TEB30A.The experiment results showed that the film of nematic liquid crystals TEB30A can produce diffraction in the four weak magnetic fields of 0,0.464 9, 0.506 2 and 0.518 5.The diffraction pattern could obviously be changed with the increasing of the magnetic strength.The number of diffraction rings increased,the width of diffraction rings became wide,and the diffraction field expanded outward.At the magnetic strength of 0.506 2 T,the interfer-ence stripes appeared on the diffracting rings.While the magnetic strength increased to 0.518 5 T, the interference stripes was becoming parallel.Under the effect of the weak magnetic field,the diver-gence of the laser beam was changed drastically in the far-field.Based on the Kirchhoff - Fraunhofer diffraction integral,the theoretical simulation results showed that,when the laser beam passed through the film of nematic liquid crystals TEB30A in the weak magnetic field,the transverse nonlin-ear phase would increase.With the weak magnetic strength increasing from 0 T to 0.518 5 T,the nonlinear phase increased from 4πto 20π.The weak magnetic field caused the nonlinear phase,resul-ting in the change of the far-field diffraction pattern.The change of the far-field diffraction pattern is also the change of the distribution of the transmitted light energy.Therefore,the technology of the weak magnetic field modulating the nematic liquid crystals can be applied to the areas of magnetic-op-tical switch and magnetic-optical limiters.%采用1.5 mW低功率的 He-Ne激光(632.8 nm)正入射向列相液晶 TEB30A薄膜,研究向列相液晶 TEB30A薄膜在不同强度的弱磁场(0、0.4649、0.5062和0.5185 T)中的远场衍射特性.实验结果表明,向列相液晶 TEB30A 薄膜在4

  16. Numerical Modeling of a Magnetic Flux Compression Experiment

    Science.gov (United States)

    Makhin, Volodymyr; Bauer, Bruno S.; Awe, Thomas J.; Fuelling, Stephan; Goodrich, Tasha; Lindemuth, Irvin R.; Siemon, Richard E.; Garanin, Sergei F.

    2007-06-01

    A possible plasma target for Magnetized Target Fusion (MTF) is a stable diffuse z-pinch in a toroidal cavity, like that in MAGO experiments. To examine key phenomena of such MTF systems, a magnetic flux compression experiment with this geometry is under design. The experiment is modeled with 3 codes: a slug model, the 1D Lagrangian RAVEN code, and the 1D or 2D Eulerian Magneto-Hydro-Radiative-Dynamics-Research (MHRDR) MHD simulation. Even without injection of plasma, high- Z wall plasma is generated by eddy-current Ohmic heating from MG fields. A significant fraction of the available liner kinetic energy goes into Ohmic heating and compression of liner and central-core material. Despite these losses, efficiency of liner compression, expressed as compressed magnetic energy relative to liner kinetic energy, can be close to 50%. With initial fluctuations (1%) imposed on the liner and central conductor density, 2D modeling manifests liner intrusions, caused by the m = 0 Rayleigh-Taylor instability during liner deceleration, and central conductor distortions, caused by the m = 0 curvature-driven MHD instability. At many locations, these modes reduce the gap between the liner and the central core by about a factor of two, to of order 1 mm, at the time of peak magnetic field.

  17. Design of an MeV ultra-fast electron diffraction experiment at Tsinghua university

    Institute of Scientific and Technical Information of China (English)

    LI Ren-Kai; TANG Chuan-Xiang; HUANG Wen-Hui; DU Ying-Chao; SHI Jia-Ru; YAN Li-Xin

    2009-01-01

    Time-resolved MeV ultra-fast electron difiraction(UED)is a powerful tool for structure dynamics studies.In this paper.we present a design of a MeV UED facility based on a photocathode RF gun at Tsinghua University.Electron beam qualities are optimized with numerical simulations,indicating that resolutions of 250 fs and 0.01 A.and bunch charge exceeding 105 electrons are expected with technically achievable machine parameters.Status of experiment preparation is also presented.

  18. Magnetic and structural properties of Sc(Fe1−xSix2 Laves phases studied by Mössbauer spectroscopy and neutron diffraction

    Directory of Open Access Journals (Sweden)

    Wiertel Marek

    2015-03-01

    Full Text Available The aim of the presented paper is to study an influence of replacement of Fe atoms by Si atoms in quasibinary Sc(Fe1−xSix2 Laves phases on their structural and magnetic properties. Powder X-ray diffraction (XRD and neutron diffraction (ND measurements carried out at different temperatures from 4.3 K up to about 700 K revealed that samples were single phase with cubic C15 structure for Si concentration x from 0.05 to 0.20 and hexagonal C14 structure for higher concentration. The results of 57Fe Mössbauer measurements showed that the Sc(Fe1−xSix2 compounds with x ≤ 0.30 are ferrimagnetic at 4.3 K. At temperature 80 K in the samples with x = 0.20 and 0.30, a magnetic cluster spin-glass state has been observed, as ferrimagnetic long-range order disappears. Such picture was supported by the results of ND measurements carried out at 8 K, which confirmed the lack of long-range order for x above 0.10 and an occurrence of hyperfine field distributions in the corresponding Mössbauer spectra. At room temperature, samples with x ≥ 0.20 became paramagnetic. A substitution of Si atoms for Fe ones leads to a decreasing of mean values of hyperfine magnetic fields in samples under investigation. From the neutron diffraction pattern analysis of Sc(Fe0.90Si0.102Fe magnetic moment was determined as to be equal to 1.5 μB at 8 K. Combining this result with a value of hyperfine magnetic field on 57Fe probes, the hyperfine coupling constant A in Sc(Fe0.90Cu0.102 phases is estimated at about 11.6 T/μB at 8 K.

  19. Experiences with archived raw diffraction images data: capturing cisplatin after chemical conversion of carboplatin in high salt conditions for a protein crystal.

    Science.gov (United States)

    Tanley, Simon W M; Diederichs, Kay; Kroon-Batenburg, Loes M J; Schreurs, Antoine M M; Helliwell, John R

    2013-11-01

    The archiving of raw diffraction images data is the focus of an IUCr Diffraction Data Deposition Working Group (see http://forums.iucr.org/). Experience in archiving and sharing of raw diffraction images data in collaboration between Manchester and Utrecht Universities, studying the binding of the important anti-cancer agents, cisplatin and carboplatin to histidine in a protein, has recently been published. Subsequently, these studies have been expanded due to further analyses of each data set of raw diffraction images using the diffraction data processing program XDS. The raw diffraction images, measured at Manchester University, are available for download at Utrecht University and now also mirrored at the Tardis Raw Diffraction Data Archive in Australia. Thus a direct comparison of processed diffraction and derived protein model data from XDS with the published results has been made. The issue of conversion of carboplatin to cisplatin under a high chloride salt concentration has been taken up and a detailed crystallographic assessment is provided. Overall, these new structural chemistry research results are presented followed by a short summary of developing raw data archiving policy and practicalities as well as documenting the challenge of making appropriate and detailed recording of the metadata for crystallography.

  20. Ion energy recovery experiment based on magnetic electro suppression

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.; Stirling, W.L.; Dagenhart, W.K.; Barber, G.C.; Ponte, N.S.

    1980-05-01

    A proof-of-principle experiment on direct recovery of residual hydrogen ions based on a magnetic electron suppression scheme is described. Ions extracted from a source plasma a few kilovolts above the ground potential (approx. 20 A) are accelerated to 40 keV by a negative potential maintained on a neutralizer gas cell. As the residual ions exit the gas cell, they are deflected from the neutral beam by a magnetic field that also suppresses gas cell electrons and then recovered on a ground-potential surface. Under optimum conditions, a recovery efficiency (the ratio of the net recovered current to the available full-energy ion current) of 80% +- 20% has been obtained. Magnetic suppression of the beam plasma electrons was rather easily achieved; however, handling the fractional-energy ions originating from molecular species (H/sub 2//sup +/ and H/sub 3//sup +/) proved to be extremely important to recovery efficiency.

  1. Diagnosing Magnetized Liner Inertial Fusion experiments on Z

    Science.gov (United States)

    Hansen, Stephanie

    2014-10-01

    Recent Magnetized Liner Inertial Fusion (MagLIF) experiments performed at Sandia's Z facility have demonstrated DD fusion neutron yields above 1012 and effective confinement of charged fusion products by the flux-compressed magnetic field signaled by >1010 secondary DT neutrons. The neutron diagnostics are complemented by an extensive suite of visible and x-ray diagnostics providing power, imaging, and spectroscopic data. This talk will present analyses of emission and absorption features from the imploding and stagnating plasma that provide a consistent picture of the magnetic drive and the temperatures, densities, mix, and gradients in the fuel and liner at stagnation. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.

  2. Final results of magnetic monopole searches with the MACRO experiment

    CERN Document Server

    Ambrosio, M; Auriemma, G; Bakari, D; Baldini, A; Barbarino, G C; Barish, B C; Battistoni, G; Becherini, Y; Bellotti, R; Bemporad, C; Bernardini, P; Bilokon, H; Bloise, C; Bower, C; Brigida, M; Bussino, S; Cafagna, F; Calicchio, M; Campana, D; Carboni, M; Caruso, R; Cecchini, S; Cei, F; Chiarella, V; Chiarusi, T; Choudhary, B C; Coutu, S; Cozzi, M; De Cataldo, G; Dekhissi, H; De Marzo, C; De Mitri, I; Derkaoui, J E; De Vincenzi, M; Di Credico, A; Erriquez, O; Favuzzi, C; Forti, C; Fusco, P; Giacomelli, G; Giannini, G; Giglietto, N; Giorgini, M; Grassi, M; Grillo, A; Guarino, F; Gustavino, C; Habig, A; Hanson, K; Heinz, R; Iarocci, E; Katsavounidis, E; Katsavounidis, I; Kearns, E; Kim, H; Kyriazopoulou, S; Kumar, A; Lamanna, E; Lane, C; Levin, D S; Lipari, P; Longley, N P; Longo, M J; Loparco, F; Maaroufi, F; Mancarella, G; Mandrioli, G; Manzoor, S; Margiotta, A; Marini, A; Martello, D; Marzari-Chiesa, A; Matteuzzi, D; Mazziotta, M N; Michael, D G; Monacelli, P; Montaruli, T; Monteno, M; Mufson, S L; Musser, J; Nicolò, D; Nolty, R; Orth, C; Osteria, G; Palamara, O; Patera, V; Patrizii, L; Pazzi, R; Peck, C W; Perrone, L; Petrera, S; Pistilli, P; Popa, V; Rainó, A; Reynoldson, J; Ronga, F; Rrhioua, A; Satriano, C; Scapparone, E; Scholberg, K; Sciubba, A; Serra, P; Sioli, M; Sirri, G; Sitta, M; Spinelli, P; Spinetti, M; Spurio, M; Steinberg, R; Stone, J L; Sulak, L R; Surdo, A; Tarle, G; Togo, V; Vakili, M; Walter, C W; Webb, R

    2002-01-01

    We present the final results obtained by the MACRO experiment in the search for GUT magnetic monopoles in the penetrating cosmic radiation, for the range 4*10/sup -5/< beta <1. Several searches with all the MACRO sub-detectors (i.e. scintillation counters, limited streamer tubes and nuclear track detectors) were performed, both in stand alone and combined ways. No candidates were detected and a 90% Confidence Level (C.L.) upper limit to the local magnetic monopole flux was set at the level of 1.4*10/sup -16/ cm/sup -2/ s/sup -1/ sr /sup -1/. This result is the first experimental limit obtained in direct searches which is well below the Parker bound in the whole beta range in which GUT magnetic monopoles are expected. (37 refs).

  3. Experiments on Inductive Magnetic Levitation with a Circular Halbach Array

    Science.gov (United States)

    Bean, Ian; Goncz, Doug; Raymer, Austin; Specht, Jason; Zalles, Ricardo; Majewski, Walerian

    2013-03-01

    Using a ring Halbach array, we are investigating a repulsive levitating force and a drag force acting on the magnet from a ring of inductors rotating below the magnet. After measuring induced currents, voltages and magnetic fields in the individual inductors (in the form of short solenoids), we investigated the dependence of lift/drag forces on the speed of relative rotation. The ratio of lift to drag increases with the angular velocity, as expected from a related theory of the induction effects in a linear motion. We are experimenting with the shape and density of inductors, and their material, in an attempt to maximize the lift at a minimal velocity of rotation. Eventually this design could have applications as frictionless bearings or as frictionless gear in a wide range of systems, especially in machinery that cannot be easily accessed.

  4. Development of a silicon microstrip detector with single photon sensitivity for fast dynamic diffraction experiments at a synchrotron radiation beam

    Science.gov (United States)

    Arakcheev, A.; Aulchenko, V.; Kudashkin, D.; Shekhtman, L.; Tolochko, B.; Zhulanov, V.

    2017-06-01

    Time-resolved experiments on the diffraction of synchrotron radiation (SR) from crystalline materials provide information on the evolution of a material structure after a heat, electron beam or plasma interaction with a sample under study. Changes in the material structure happen within a microsecond scale and a detector with corresponding parameters is needed. The SR channel 8 of the VEPP-4M storage ring provides radiation from the 7-pole wiggler that allows to reach several tens photons within one μs from a tungsten crystal for the most intensive diffraction peak. In order to perform experiments that allow to measure the evolution of tungsten crystalline structure under the impact of powerful laser beam, a new detector is developed, that can provide information about the distribution of a scattered SR flux in space and its evolution in time at a microsecond scale. The detector is based on the silicon p-in-n microstrip sensor with DC-coupled metal strips. The sensor contains 1024 30 mm long strips with a 50 μm pitch. 64 strips are bonded to the front-end electronics based on APC128 ASICs. The APC128 ASIC contains 128 channels that consist of a low noise integrator with 32 analogue memory cells each. The integrator equivalent noise charge is about 2000 electrons and thus the signal from individual photons with energy above 40 keV can be observed. The signal can be stored at the analogue memory with 10 MHz rate. The first measurements with the beam scattered from a tungsten crystal with energy near 60 keV demonstrated the capability of this prototype to observe the spatial distribution of the photon flux with the intensity from below one photon per channel up to 0~10 photons per channel with a frame rate from 10 kHz up to 1 MHz.

  5. Ray-tracing simulations of spherical Johann diffraction spectrometer for in-beam X-ray experiments

    Energy Technology Data Exchange (ETDEWEB)

    Jagodziński, P., E-mail: jagodzin@tu.kielce.pl [Department of Physics, Kielce University of Technology, Tysiaclecia PP 7, 25-314 Kielce (Poland); Pajek, M.; Banaś, D. [Institute of Physics, Jan Kochanowski University, Świȩtokrzyska 15, 25-406 Kielce (Poland); Beyer, H.F. [GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt (Germany); Trassinelli, M. [Institut des NanoSciences de Paris, Université Pierre et Marie Curie, 4 Place Jussieu, 75015 Paris (France); Stoehlker, Th. [GSI Helmholtzzentrum für Schwerionenforschung, D-64291 Darmstadt (Germany); Helmholtz-Insitut Jena, D-07743 Jena (Germany); Institut für Optic und Quantenelektronik, Friedrich-Schiller-Universität Jena, D-07743 Jena (Germany)

    2014-07-01

    The results of the Monte-Carlo ray-tracing simulations for a Johann-type Bragg spectrometer with spherically curved-crystal designed to detect the X-rays from a fast-moving source are reported. These calculations were performed to optimize the X-ray spectrometer to be used at the gas-target installed at ion storage ring for high-resolution X-ray experiments. In particular, the two-dimensional distributions of detected photons were studied using the Monte-Carlo method both for the stationary and moving X-ray sources, taking into account a detailed description of X-ray source and X-ray diffraction on the crystal as well as a role of the Doppler effect for in-beam experiments. The origin of the asymmetry of observed X-ray profiles was discussed in detail and the procedure to derive a precise (sub-eV) X-ray transition energy for such asymmetric profiles was proposed. The results are important for the investigations of 1s2p{sup 3}P{sub 2}→1s2s{sup 3}S{sub 1} intrashell transition in excited He-like uranium ions in in-beam X-ray experiments.

  6. Development and operational experience of magnetic horn system for T2K experiment

    CERN Document Server

    Sekiguchi, T; Fujii, Y; Hagiwara, M; Hasegawa, T; Hayashi, K; Ishida, T; Ishii, T; Kobayashi, H; Kobayashi, T; Koike, S; Koseki, K; Maruyama, T; Matsumoto, H; Nakadaira, T; Nakamura, K; Nakayoshi, K; Nishikawa, K; Oyama, Y; Sakashita, K; Shibata, M; Suzuki, Y; Tada, M; Takahashi, K; Tsukamoto, T; Yamada, Y; Yamanoi, Y; Yamaoka, H; Ichikawa, A K; Kubo, H; Butcher, Z; Coleman, S; Missert, A; Spitz, J; Zimmerman, E D; Tzanov, M; Bartoszek, L

    2015-01-01

    A magnetic horn system to be operated at a pulsed current of 320 kA and to survive high-power proton beam operation at 750 kW was developed for the T2K experiment. The first set of T2K magnetic horns was operated for over 12 million pulses during the four years of operation from 2010 to 2013, under a maximum beam power of 230 kW, and $6.63\\times10^{20}$ protons were exposed to the production target. No significant damage was observed throughout this period. This successful operation of the T2K magnetic horns led to the discovery of the $\

  7. Experiments of cylindrical isentropic compression by ultrahigh magnetic field

    Directory of Open Access Journals (Sweden)

    Gu Zhuowei

    2015-01-01

    Full Text Available The high Explosive Magnetic Flux Implosion Compression Generator (EMFICG is a kind of unique high energy density dynamic technique with characters like ultrahigh pressure and low temperature rising and could be suitable as a tool of cylindrical isentropic compression. The Institute of Fluid Physics, Chinese Academy of Engineering Physics (IFP, CAEP have developed EMFICG technique and realized cylindrical isentropic compression. In the experiments, a seed magnetic field of 5–6 Tesla were built first and compressed by a stainless steel liner which is driven by high explosive. The inner free surface velocity of sample was measured by PDV. The isentropic compression of a copper sample was verified and the isentropic pressure is over 100 GPa. The cylindrical isentropic compression process has been numerical simulated by 1D MHD code and the simulation results were compared with the experiments. Compared with the transitional X-ray flash radiograph measurement, this method will probably promote the data accuracy.

  8. IDATEN and G-SITENNO: GUI-assisted software for coherent X-ray diffraction imaging experiments and data analyses at SACLA.

    Science.gov (United States)

    Sekiguchi, Yuki; Yamamoto, Masaki; Oroguchi, Tomotaka; Takayama, Yuki; Suzuki, Shigeyuki; Nakasako, Masayoshi

    2014-11-01

    Using our custom-made diffraction apparatus KOTOBUKI-1 and two multiport CCD detectors, cryogenic coherent X-ray diffraction imaging experiments have been undertaken at the SPring-8 Angstrom Compact free electron LAser (SACLA) facility. To efficiently perform experiments and data processing, two software suites with user-friendly graphical user interfaces have been developed. The first is a program suite named IDATEN, which was developed to easily conduct four procedures during experiments: aligning KOTOBUKI-1, loading a flash-cooled sample into the cryogenic goniometer stage inside the vacuum chamber of KOTOBUKI-1, adjusting the sample position with respect to the X-ray beam using a pair of telescopes, and collecting diffraction data by raster scanning the sample with X-ray pulses. Named G-SITENNO, the other suite is an automated version of the original SITENNO suite, which was designed for processing diffraction data. These user-friendly software suites are now indispensable for collecting a large number of diffraction patterns and for processing the diffraction patterns immediately after collecting data within a limited beam time.

  9. Crystallographic parameters of magnetic Pr2Fe14-xCoxB-type alloys determined using anomalous x-ray diffraction with synchrotron radiation

    Science.gov (United States)

    Galego, E.; Serna, M. M.; Ramanathan, L. V.; Faria, R. N.

    2017-02-01

    Anomalous x-ray synchrotron diffraction was used to determine the crystallographic parameters of PrFeCoB-based magnetic alloys. The effect of cobalt concentration on the crystallographic parameters of the magnetically hard Pr2Fe14-xCoxB phase was studied. The results indicate that addition of cobalt has a marked effect on crystal structure. Variation of the c parameter decreased twice as much as the a parameter with increase in Co content. The positions of inequivalent atoms of the magnetically hard matrix phase ϕ in the Pr-based alloys were determined using Rietveld refinement. This permitted determination of the relative distance of each inequivalent atom from its nearest neighbors. Cobalt occupied the 16k2 site and Fe had a tendency to occupy the 8j2 sites located between the Kagomé layers.

  10. Limits on the neutrino magnetic moment from the MUNU experiment

    CERN Document Server

    Daraktchieva, Z; Link, O; Amsler, Claude; Avenier, M; Broggini, C; Busto, J; Cerna, C; Gervasio, G; Jeanneret, J B; Jonkmans, G; Koang, D H; Lebrun, D; Ould-Saada, F; Puglierin, G; Stutz, A; Tadsen, A; Vuilleumier, J L

    2003-01-01

    The MUNU experiment was carried out at the Bugey nuclear power reactor. The aim was the study of electron antineutrino-electron elastic scattering at low energy. The recoil electrons were recorded in a gas time projection chamber, immersed in a tank filled with liquid scintillator serving as veto detector, suppressing in particular Compton electrons. The measured electron recoil spectrum is presented. Upper limits on the neutrino magnetic moment were derived and are discussed.

  11. UCLA-KIAE focusing permanent magnet undulator for SASE experiment

    Science.gov (United States)

    Osmanov, N.; Tolmachev, S.; Varfolomeev, A.; Varfolomeev, A. A.; Frigola, P.; Hogan, M.; Pellegrini, C.; Carr, R.; Lidia, S.

    1998-02-01

    A description of a new 2 m undulator is presented which was specially designed and manufactured for a SASE mode FEL experiment. It is a one section two plane focusing permanent magnet construction. The uniform period length is 2.06 cm, total number of periods is 98. The peak field on the axis is 5.4 kG for a 5 mm gap.

  12. Recent experiments in inverse kinematics with the magnetic spectrometer PRISMA

    Directory of Open Access Journals (Sweden)

    Fioretto E.

    2016-01-01

    Full Text Available In the last period, two classes of experiments have been carried out with the large acceptance magnetic spectrometer PRISMA. In particular, the one- and two-neutron transfer processes at energies ranging from the Coulomb barrier to deep below it and the population of exotic neutron rich nuclei in the A~130 and A~200 mass regions have been studied. Both kinds of experiments have been performed in inverse kinematics identifying in A, Z and velocity the light target-like recoils with PRISMA placed at very forward angles in order to have, at the same time, high efficiency and good energy and mass resolutions.

  13. Non-destructive magneto-strain analysis of YB2Cu3Oy superconducting magnets using neutron diffraction in the time-of-flight mode

    Science.gov (United States)

    Tomita, M.; Muralidhar, M.; Suzuki, K.; Ishihara, A.; Fukumoto, Y.; Osamura, K.; Machiya, S.; Harjo, S.

    2012-09-01

    In general, neutron diffraction allows a non-destructive investigation of bulk samples. In this study, a magneto-strain analysis of the trapped field in YB2Cu3Oy "YBCO" superconducting bulks was carried out at 45 K using neutron diffraction time-of-flight (TOF) method. The TAKUMI TOF neutron diffractometer offers unique advantages, including accommodation of large objectives, control of the experimental set-up using a 4-axial goniometer (XYZθ), and a positional resolution of 0.01 mm allowing an accurate sample positioning. As a result, the lattice strain in the YB2Cu3Oy material could be estimated in both radial and hoop directions by estimating the difference of plane spacing with/without the trapped magnetic field. The results indicate that the samples with a low trapped field values have smaller magnetic strain than those with a high trapped field. Further, the strain in the hoop direction is higher than that in the radial direction. The present results indicate that neutron diffraction measurements are an effective method for evaluating the bulk residual strains in a non-destructive manner.

  14. Weissenberg-type neutron diffraction camera and its application to the structural and magnetic phase transitions of KMnF{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, S. [Kyushu University, Department of Physics, Faculty of Science, Fukuoka (Japan); University of Tokyo, Neutron Scattering Laboratory, ISSP, Ibaraki (Japan); Yoshimura, M.; Hidaka, M. [Kyushu University, Department of Physics, Faculty of Science, Fukuoka (Japan); Yoshizawa, H. [University of Tokyo, Neutron Scattering Laboratory, ISSP, Ibaraki (Japan)

    2006-07-15

    A Weissenberg-type neutron diffraction camera (W-NDC) equipped with a neutron imaging-plate (NIP) has been developed. The W-NDC gives Weissenberg-type and rotational diffraction patterns at low-temperature (10 Kdiffracted from the aluminum containers and the specimen holder, a radial slit with several polymer sheets coated with {sup 6}LiF powder is continuously oscillated around the specimen during measurements. A test structural analysis for a single crystal NaCl suggests that the integrated intensities of reflections obtained from the Weissenberg-type diffraction patterns adequately satisfy a structural refinement by means of a least square method, though a fading effect of the photon energy stored in the NIP should be regarded during measurements. Structural and magnetic phase transitions in KMnF{sub 3} have been studied by using the W-NDC, to eliminate an inconsistency for temperature, and to enable an ordering of the phase transition as reported. (orig.)

  15. Gravitropic mechanisms derived from space experiments and magnetic gradients.

    Science.gov (United States)

    Hasenstein, Karl H.; Park, Myoung Ryoul

    2016-07-01

    Gravitropism is the result of a complex sequence of events that begins with the movement of dense particles, typically starch-filled amyloplasts in response to reorientation. Although these organelles change positions, it is not clear whether the critical signal is derived from sedimentation or dynamic interactions of amyloplasts with relevant membranes. Substituting gravity by high-gradient magnetic fields (HGMF) provides a localized stimulus for diamagnetic starch that is specific for amyloplasts and comparable to gravity without affecting other organelles. Experiments with Brassica rapa showed induction of root curvature by HGMF when roots moved sufficiently close to the magnetic gradient-inducing foci. The focused and short-range effectiveness of HGMFs provided a gravity-like stimulus and affected related gene expression. Root curvature was sensitive to the mutual alignment between roots and HGMF direction. Unrelated to any HGMF effects, the size of amyloplasts in space-grown roots increased by 30% compared to ground controls and suggests enhanced sensitivity in a gravity-reduced environment. Accompanying gene transcription studies showed greater differences between HGMF-exposed and space controls than between space and ground controls. This observation may lead to the identification of gravitropism-relevant genes. However, space grown roots showed stronger transcription of common reference genes such as actin and ubiquitin in magnetic fields than in non-magnetic conditions. In contrast, α-amylase, glucokinase and PIN encoding genes were transcribed stronger under non-magnetic conditions than under HGMF. The large number of comparisons between space, ground, and HGMF prompted the assessment of transcription differences between root segments, root-shoot junction, and seeds. Because presumed transcription of reference genes varied more than genes of interest, changes in gene expression cannot be based on reference genes. The data provide an example of complex

  16. First spin-resolved electron distributions in crystals from combined polarized neutron and X-ray diffraction experiments

    Directory of Open Access Journals (Sweden)

    Maxime Deutsch

    2014-05-01

    Full Text Available Since the 1980s it has been possible to probe crystallized matter, thanks to X-ray or neutron scattering techniques, to obtain an accurate charge density or spin distribution at the atomic scale. Despite the description of the same physical quantity (electron density and tremendous development of sources, detectors, data treatment software etc., these different techniques evolved separately with one model per experiment. However, a breakthrough was recently made by the development of a common model in order to combine information coming from all these different experiments. Here we report the first experimental determination of spin-resolved electron density obtained by a combined treatment of X-ray, neutron and polarized neutron diffraction data. These experimental spin up and spin down densities compare very well with density functional theory (DFT calculations and also confirm a theoretical prediction made in 1985 which claims that majority spin electrons should have a more contracted distribution around the nucleus than minority spin electrons. Topological analysis of the resulting experimental spin-resolved electron density is also briefly discussed.

  17. Demonstration of thermonuclear conditions in magnetized liner inertial fusion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, M. R.; Slutz, S. A.; Sefkow, A. B.; Hahn, K. D.; Hansen, S. B.; Knapp, P. F.; Schmit, P. F.; Ruiz, C. L.; Sinars, D. B.; Harding, E. C.; Jennings, C. A.; Awe, T. J.; Geissel, M.; Rovang, D. C.; Smith, I. C.; Chandler, G. A.; Cooper, G. W.; Cuneo, M. E.; Harvey-Thompson, A. J.; Hess, M. H. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185 (United States); and others

    2015-05-15

    The magnetized liner inertial fusion concept [S. A. Slutz et al., Phys. Plasmas 17, 056303 (2010)] utilizes a magnetic field and laser heating to relax the pressure requirements of inertial confinement fusion. The first experiments to test the concept [M. R. Gomez et al., Phys. Rev. Lett. 113, 155003 (2014)] were conducted utilizing the 19 MA, 100 ns Z machine, the 2.5 kJ, 1 TW Z Beamlet laser, and the 10 T Applied B-field on Z system. Despite an estimated implosion velocity of only 70 km/s in these experiments, electron and ion temperatures at stagnation were as high as 3 keV, and thermonuclear deuterium-deuterium neutron yields up to 2 × 10{sup 12} have been produced. X-ray emission from the fuel at stagnation had widths ranging from 50 to 110 μm over a roughly 80% of the axial extent of the target (6–8 mm) and lasted approximately 2 ns. X-ray yields from these experiments are consistent with a stagnation density of the hot fuel equal to 0.2–0.4 g/cm{sup 3}. In these experiments, up to 5 × 10{sup 10} secondary deuterium-tritium neutrons were produced. Given that the areal density of the plasma was approximately 1–2 mg/cm{sup 2}, this indicates the stagnation plasma was significantly magnetized, which is consistent with the anisotropy observed in the deuterium-tritium neutron spectra. Control experiments where the laser and/or magnetic field were not utilized failed to produce stagnation temperatures greater than 1 keV and primary deuterium-deuterium yields greater than 10{sup 10}. An additional control experiment where the fuel contained a sufficient dopant fraction to substantially increase radiative losses also failed to produce a relevant stagnation temperature. The results of these experiments are consistent with a thermonuclear neutron source.

  18. Influence on cell death of high frequency motion of magnetic nanoparticles during magnetic hyperthermia experiments

    Science.gov (United States)

    Hallali, N.; Clerc, P.; Fourmy, D.; Gigoux, V.; Carrey, J.

    2016-07-01

    Studies with transplanted tumors in animals and clinical trials have provided the proof-of-concept of magnetic hyperthermia (MH) therapy of cancers using iron oxide nanoparticles. Interestingly, in several studies, the application of an alternating magnetic field (AMF) to tumor cells having internalized and accumulated magnetic nanoparticles (MNPs) into their lysosomes can induce cell death without detectable temperature increase. To explain these results, among other hypotheses, it was proposed that cell death could be due to the high-frequency translational motion of MNPs under the influence of the AMF gradient generated involuntarily by most inductors. Such mechanical actions of MNPs might cause cellular damages and participate in the induction of cell death under MH conditions. To test this hypothesis, we developed a setup maximizing this effect. It is composed of an anti-Helmholtz coil and two permanent magnets, which produce an AMF gradient and a superimposed static MF. We have measured the MNP heating power and treated tumor cells by a standard AMF and by an AMF gradient, on which was added or not a static magnetic field. We showed that the presence of a static magnetic field prevents MNP heating and cell death in standard MH conditions. The heating power of MNPs in an AMF gradient is weak, position-dependent, and related to the presence of a non-zero AMF. Under an AMF gradient and a static field, no MNP heating and cell death were measured. Consequently, the hypothesis that translational motions could be involved in cell death during MH experiments is ruled out by our experiments.

  19. Diagnosing magnetized liner inertial fusion experiments on Z

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, S. B., E-mail: sbhanse@sandia.gov; Gomez, M. R.; Sefkow, A. B.; Slutz, S. A.; Sinars, D. B.; Hahn, K. D.; Harding, E. C.; Knapp, P. F.; Schmit, P. F.; Awe, T. J.; McBride, R. D.; Jennings, C. A.; Geissel, M.; Harvey-Thompson, A. J.; Peterson, K. J.; Rovang, D. C.; Chandler, G. A.; Cooper, G. W.; Cuneo, M. E.; Hess, M. H. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185 (United States); and others

    2015-05-15

    Magnetized Liner Inertial Fusion experiments performed at Sandia's Z facility have demonstrated significant thermonuclear fusion neutron yields (∼10{sup 12} DD neutrons) from multi-keV deuterium plasmas inertially confined by slow (∼10 cm/μs), stable, cylindrical implosions. Effective magnetic confinement of charged fusion reactants and products is signaled by high secondary DT neutron yields above 10{sup 10}. Analysis of extensive power, imaging, and spectroscopic x-ray measurements provides a detailed picture of ∼3 keV temperatures, 0.3 g/cm{sup 3} densities, gradients, and mix in the fuel and liner over the 1–2 ns stagnation duration.

  20. Optimal Liner Material for Near Term Magnetized Liner Fusion Experiments

    Science.gov (United States)

    Slutz, Stephen

    2012-10-01

    Substantial fusion yields are predicted with existing pulsed power machines driving cylindrical liner implosions with preheated and magnetized deuterium-tritium [S.A. Slutz et al Phys. Plasmas 17, 056303 (2010)]. Experiments are planned using the Z accelerator to drive these implosions. However, the peak current, the laser heating energy, and the applied magnetic field will be less than optimal. We present simulations which show, that under these conditions, the yield can be improved significantly by decreasing the density of the liner material, e.g. Lithium substituted for Beryllium. Furthermore, the simulations show that decreasing the liner density allows the use of very low aspect ratio (R/δR) liners, while still obtaining interesting yields. Low aspect ratio liners should be more robust to the Rayleigh-Taylor instability.

  1. Interplay between crystal and magnetic structures in YFe2(HαD1-α)4.2 compounds studied by neutron diffraction

    Science.gov (United States)

    Paul-Boncour, V.; Guillot, M.; Isnard, O.; Ouladdiaf, B.; Hoser, A.; Hansen, T.; Stuesser, N.

    2017-01-01

    We report a detailed magnetic structure investigation of YFe2(HαD1-α)4.2 (α=0, 0.64, 1) compounds presenting a strong (H,D) isotope effect by neutron diffraction and Mössbauer spectroscopy analysis. They crystallize in the same monoclinic structure (Pc space group) with 8 inequivalent Fe sites having different H(D) environment. At low temperature, the compounds are ferromagnetic (FM) and show an easy magnetization axis perpendicular to the b axis and only slightly tilted away from the c axis. Upon heating, they display a first order transition from a ferromagnetic towards an antiferromagnetic (AFM) structure at TM0 which is sensitive to the H/D isotope nature. The AFM cell is described by doubling the crystal cell along the monoclinic b axis. It presents an unusual coexistence of non magnetic Fe layer sandwiched by two thicker ferromagnetic Fe layers which are antiparallel to each other. This FM-AFM transition is driven by the loss of ordered moment on one Fe site (Fe7) through an itinerant electron metamagnetic (IEM) behaviour. The key role of the Fe7 position is assigned to both its hydrogen rich atomic environment and its geometric position. Above TM0 a field induced metamagnetic transition is observed from the AFM towards the FM structure accompanied by a cell volume increase. Both thermal and magnetic field dependence of the magnetic structure are found strongly related to the anisotropic cell distortion induced by (H,D) order in interstitial sites.

  2. "Smart" Magnetic Fluids Experiment Operated on the International Space Station

    Science.gov (United States)

    Agui, Juan H.; Lekan, Jack F.

    2004-01-01

    InSPACE is a microgravity fluid physics experiment that was operated on the International Space Station (ISS) in the Microgravity Science Glovebox from late March 2003 through early July 2003. (InSPACE is an acronym for Investigating the Structure of Paramagnetic Aggregates From Colloidal Emulsions.) The purpose of the experiment is to obtain fundamental data of the complex properties of an exciting class of smart materials termed magnetorheological (MR) fluids. MR fluids are suspensions, or colloids, comprised of small (micrometer-sized) superparamagnetic particles in a nonmagnetic medium. Colloids are suspensions of very small particles suspended in a liquid. (Examples of other colloids are blood, milk, and paint.) These controllable fluids can quickly transition into a nearly solid state when exposed to a magnetic field and return to their original liquid state when the magnetic field is removed. Controlling the strength of the magnetic field can control the relative stiffness of these fluids. MR fluids can be used to improve or develop new seat suspensions, robotics, clutches, airplane landing gear, and vibration damping systems. The principal investigator for InSPACE is Professor Alice P. Gast of the Massachusetts Institute of Technology (MIT). The InSPACE hardware was developed at the NASA Glenn Research Center. The InSPACE samples were delivered to the ISS in November 2002, on the Space Shuttle Endeavour, on Space Station Utilization Flight UF-2/STS113. Operations began on March 31, 2003, with the processing of three different particle size samples at multiple test parameters. This investigation focused on determining the structural organization of MR colloidal aggregates when exposed to a pulsing magnetic field. On Earth, the aggregates take the shape of footballs with spiky tips. This characteristic shape may be influenced by the pull of gravity, which causes most particles initially suspended in the fluid to sediment, (i.e., settle and collect at the

  3. Magnetic Monopole Search at high altitude with the SLIM experiment

    CERN Document Server

    Balestra, S; Cozzi, M; Errico, M; Fabbri, F; Giacomelli, G; Giacomelli, R; Giorgini, M; Kumar, A; Manzoor, S; McDonald, J; Mandrioli, G; Marcellini, S; Margiotta, A; Medinaceli, E; Patrizii, L; Pinfold, J L; Popa, V; Qureshi, I E; Saavedra, O; Sahnoun, Z; Sirri, G; Spurio, M; Togo, V; Velarde, A; Zanini, A

    2008-01-01

    The SLIM experiment was a large array of nuclear track detectors located at the Chacaltaya high altitude Laboratory (5230 m a.s.l.). The detector was in particular sensitive to Intermediate Mass Magnetic Monopoles, with masses 10^5 < M <10^{12} GeV. From the analysis of the full detector exposed for more than 4 years a flux upper limit of 1.3 x 10^{-15} cm^{-2} s^{-1} sr^{-1} for downgoing fast Intermediate Mass Monopoles was established at the 90% C.L.

  4. Room temperature neutron diffraction, optical and magnetic properties of Co(Cr1-xMnx)2O4 (x =0.0 and 0.30)

    Science.gov (United States)

    Kumar, Ram; Padam, R.; Rayaprol, S.; Siruguri, V.; Pal, D.

    2017-05-01

    We report here the effect of 30% Mn substitution on structure and magnetic properties of multiferroic CoCr2O4. Room temperature neutron diffraction studies were carried out on polycrystalline Co(Cr1-xMnx)2O4 (x=0.00 and 0.30) samples to determine structural properties. It has been observed that 30% Mn substitution for Cr in CoCr2O4 leads to increase in the ferrimagnetic transition temperature, (Tc) from ˜96 K to ˜114 K along with the magneto-structural transition temperature, (Ts) from ˜26 K to ˜32 K. In addition, optical properties were studied by UV-visible technique in the range of 200-800 nm. The energy band gap is found to decrease in compare to parent compound. Both magnetization and band gap variation can be explained using the spin-exchange interactions present in these systems.

  5. Preparation and characterisation of magnetic nanostructured samples for inelastic neutron scattering experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kreuzpaintner, Wolfgang

    2010-06-22

    Recent advances in thin-film structuring techniques have generated significant interest in the dynamics of spin waves in magnetic nanostructures and the possible use of inelastic neutron scattering (INS) for their investigation. This thesis describes the design and implementation, at GKSS Research Centre, of equipment for preparation of large and laterally submicron and nanometre structured magnetic samples for such future INS experiments. After a brief resume on spin waves in nanostructures, the development work on new purpose-designed equipment, including high vacuum (HV) argon ion beam milling and ultra high vacuum (UHV) e-beam evaporation setups, is described. Ni nanodot as well as Ni and novel Gd nanowire samples were prepared using combinations of sputter deposition, laser interference lithography, argon ion beam milling, e-beam evaporation and self organisation techniques. With reference to sample preparation, epitaxial growth studies for Ni on Si(100) substrate were performed, resulting in the development of a new deposition process, which by thermal tuning allows for the direct epitaxial growth of Ni on Si with unprecedented crystalline quality. The results of various characterisation experiments on the prepared nanostructured samples, including Scanning Electron Microscopy (SEM), microprobe analysis, Atomic and Magnetic Force Microscopy (AFM/MFM), Vibrating Sample Magnetometry (VSM), X-ray Diffraction (XRD) and Reflectivity (XRR), unpolarised and Polarised Neutron Scattering (PNR) and off-specular scattering by X-rays and neutrons using rocking scans and Time-Of-Flight Grazing Incidence Small Angle Neutron Scattering (TOF-GISANS), together with various analysis procedures such as Distorted-Wave Born Approximation (DWBA), are reported. The analysis of a Gd nanowire sample by TOF-GISANS led to a novel evaluation technique which in comparison with single wavelength methods allows portions of reciprocal space to be scanned without changing the angle of

  6. Magnetized Plasma Experiments Using Thermionic- Thermoelectronic Plasma Emitter

    Science.gov (United States)

    Kawamori, Eiichirou; Cheng, C. Z.; Fujikawa, Nobuko; Lee, Jyun-Yi; Peng, Albert

    2008-11-01

    We are developing a magnetic mirror device, which is the first magnetized plasma device in Taiwan, to explore basic plasma sciences relevant to fusion, space and astrophysical plasmas. Our research subjects include electromagnetically induced transparency (EIT), Alfven wave physics, and plasma turbulence. A large diameter (> 200 mm) plasma emitter1, which utilizes thermionic- thermoelectronic emission from a mixture of LaB6 (Lanthanum-hexaboride) and beta-eucryptite (lithium type aluminosylicate) powders, is employed as a plasma source because of its production ability of fully ionized plasma and controllability of plasma emission rate. The plasma emitter has been installed recently and investigation of its characteristics will be started. The employment of beta-eucryptite in plasma emitter is the first experimental test because such investigation of beta-eucryptite has previously been used only for Li+-ion source2. Our plan for magnetized plasma experiments and results of the plasma emitter investigation will be presented. 1. K. Saeki, S. Iizuka, N. Sato, and Y. Hatta, Appl. Phys. Lett., 37, 1980, pp. 37-38. 2. M. Ueda, R. R. Silva, R. M. Oliveira, H. Iguchi, J. Fujita and K. Kadota, J. Phys. D: Appl. Phys. 30 1997, pp. 2711--2716.

  7. Ratio of the contributions real and virtual photons diffraction in thin perfect crystals. Comparison of calculation and experiment

    Science.gov (United States)

    Goponov, Yu. A.; Laktionova, S. A.; Sidnin, M. A.; Vnukov, I. E.

    2017-07-01

    To evaluate and improve the previously proposed method of calculating diffracted photon yields in thin perfect crystals, a comparison between calculated and experimental results in wide range of photons and electrons energy was carried out. It is shown that the proposed method describes all investigated experimental results for bremsstrahlung diffraction and transition radiation one with an error less than ten-fifteen percent. Consequently, the method may be used for calculation of the electron beam divergence influence on the diffracted transition radiation angular distribution.

  8. Millimeter-Gap Magnetically Insulated Transmission Line Power Flow Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Hutsel, Brian Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stoltzfus, Brian S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fowler, William E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); LeChien, Keith R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mazarakis, Michael G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Moore, James K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mulville, Thomas D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Savage, Mark E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stygar, William A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); McKenney, John L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jones, Peter A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); MacRunnels, Diego J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Long, Finis W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Porter, John L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-09-01

    An experiment platform has been designed to study vacuum power flow in magnetically insulated transmission lines (MITLs). The platform was driven by the 400-GW Mykonos-V accelerator. The experiments conducted quantify the current loss in a millimeter-gap MITL with respect to vacuum conditions in the MITL for two different gap distances, 1.0 and 1.3 mm. The current loss for each gap was measured for three different vacuum pump down times. As a ride along experiment, multiple shots were conducted with each set of hardware to determine if there was a conditioning effect to increase current delivery on subsequent shots. The experiment results revealed large differences in performance for the 1.0 and 1.3 mm gaps. The 1.0 mm gap resulted in current loss of 40%-60% of peak current. The 1.3 mm gap resulted in current losses of less than 5% of peak current. Classical MITL models that neglect plasma expansion predict that there should be zero current loss, after magnetic insulation is established, for both of these gaps. The experiments result s indicate that the vacuum pressure or pump down time did not have a significant effect on the measured current loss at vacuum pressures between 1e-4 and 1e-5 Torr. Additionally, there was not repeatable evidence of a conditioning effect that reduced current loss for subsequent full-energy shots on a given set of hardware. It should be noted that the experiments conducted likely did not have large loss contributions due to ion emission from the anode due to the relatively small current densi-ties (25-40 kA/cm) in the MITL that limited the anode temperature rise due to ohmic heating. The results and conclusions from these experiments may have limited applicability to MITLs of high current density (>400 kA/cm) used in the convolute and load region of the Z which experience temperature increases of >400° C and generate ion emission from anode surfaces.

  9. A neutron diffraction study of RMn2O5 multiferroics

    Science.gov (United States)

    Radaelli, P. G.; Chapon, L. C.

    2008-10-01

    The magnetic properties of RMn2O5 multiferroics as obtained by unpolarized and polarized neutron diffraction experiments are reviewed. We discuss the qualitative features of the magnetic phase diagram in both zero magnetic field and in field and analyze the commensurate magnetic structure and its coupling to an applied electric field. The origin of ferroelectricity is discussed based on calculations of the ferroelectric polarization predicted by different microscopic coupling mechanisms (exchange-striction and cycloidal spin-orbit models). A minimal model containing a small set of parameters is also presented in order to understand the propagation of the magnetic structure along the c-direction.

  10. Atomic-Beam Magnetic Resonance Experiments at ISOLDE

    CERN Multimedia

    2002-01-01

    The aim of the atomic-beam magnetic resonance (ABMR) experiments at ISOLDE is to map the nuclear behaviour in wide regions of the nuclear chart by measuring nuclear spins and moments of ground and isomeric states. This is made through an investigation of the atomic hyperfine structure of free, neutral atoms in a thermal atomic-beam using radio-frequency techniques. On-line operation allows the study of short-lived nuclei far from the region of beta-stability.\\\\ \\\\ The ABMR experiments on the |2S^1 ^2 elements Rb, Cs, Au and Fr have been completed, and present efforts are directed towards the elements with an open p-shell and on the rare-earth elements.\\\\ \\\\ The experimental data obtained are compared with results from model calculations, giving information on the single-particle structure and on the nuclear shape parameters.

  11. The magnetized steel and scintillator calorimeters of the MINOS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Michael, : D.G.

    2008-05-01

    The Main Injector Neutrino Oscillation Search (MINOS) experiment uses an accelerator-produced neutrino beam to perform precision measurements of the neutrino oscillation parameters in the 'atmospheric neutrino' sector associated with muon neutrino disappearance. This long-baseline experiment measures neutrino interactions in Fermilab's NuMI neutrino beam with a near detector at Fermilab and again 735 km downstream with a far detector in the Soudan Underground Laboratory in northern Minnesota. The two detectors are magnetized steel-scintillator tracking calorimeters. They are designed to be as similar as possible in order to ensure that differences in detector response have minimal impact on the comparisons of event rates, energy spectra and topologies that are essential to MINOS measurements of oscillation parameters. The design, construction, calibration and performance of the far and near detectors are described in this paper.

  12. Magnetic Field Experiment on Yinghuo-1 at Mars

    Science.gov (United States)

    Zhao, Hua

    Magnetic Field Experiment on Yinghuo-1 at Mars Hua Zhao, G. W. Zhu, J. D. Wang, M. F. Yu, L. Li, Y. Q. Sun, S. W. Chen, H. Z. Liao, and B. Zhou Center for Space Science and Applied Research (CSSAR), Chinese Academy of Sciences, Beijing, China Abstract: A micro-satellite, Yinghuo-1, would be launched with Phobos-Grunt in October, 2009 to investigate the space environment around Mars. YH-1 and Phobos-Grunt forms a twopoint measurement configuration in the Martian space environment, and equipped with similar magnetic field and plasma detecting payload on two spacecraft would give some coordinated exploration around Mars. YH-1 would orbit Mars with periapsis of 800 km above the Martian surface, and apoapsis about 80000 km to the center of Mars. The orbit inclination is in the range of 0—7o to the Martian equator. A flux-gate type magnetometer, with two sensors, is developed for YH-1 spacecraft. Two sensors are mounted on one-side of the deployable solar panel with a radial separation about 45 cm to function as a gradiometer to minimize the affects of platform remanence. The dynamic range of √ magnetometer is with a 16-bit ADC converter, and the the noise level is better than 0.01 nT/ Hz, to measure three-component magnetic field from DC to 10Hz. Flux-gate magnetometer would work together with the Plasma Package onboard of YH-1 to investigate the Martian bow shock, magnetosheath, magnetic pileup region (MPR). A detail description of the flux-gate magnetometer is presented in this paper, with some test and calibration results.

  13. A few simple classroom experiments with a permanent U-shaped magnet

    Science.gov (United States)

    Babović, Miloš; Babović, Vukota

    2017-01-01

    A few simple experiments in the magnetic field of a permanent U-shaped magnet are described. Among them, pin oscillations inside the magnet are particularly interesting. These easy to perform and amusing measurements can help pupils understand magnetic phenomena and mutually connect knowledge of various physics branches.

  14. Fiber diffraction without fibers.

    Science.gov (United States)

    Poon, H-C; Schwander, P; Uddin, M; Saldin, D K

    2013-06-28

    Postprocessing of diffraction patterns of completely randomly oriented helical particles, as measured, for example, in so-called "diffract-and-destroy" experiments with an x-ray free electron laser can yield "fiber diffraction" patterns expected of fibrous bundles of the particles. This will allow "single-axis alignment" to be performed computationally, thus obviating the need to do this by experimental means such as forming fibers and laser or flow alignment. The structure of such particles may then be found by either iterative phasing methods or standard methods of fiber diffraction.

  15. X-ray diffraction observations of a charge-density-wave order in superconducting ortho-II YBa2Cu3O6.54 single crystals in zero magnetic field.

    Science.gov (United States)

    Blackburn, E; Chang, J; Hücker, M; Holmes, A T; Christensen, N B; Liang, Ruixing; Bonn, D A; Hardy, W N; Rütt, U; Gutowski, O; von Zimmermann, M; Forgan, E M; Hayden, S M

    2013-03-29

    X-ray diffraction measurements show that the high-temperature superconductor YBa2Cu3O6.54, with ortho-II oxygen order, has charge-density-wave order in the absence of an applied magnetic field. The dominant wave vector of the charge density wave is q(CDW)=(0,0.328(2),0.5), with the in-plane component parallel to the b axis (chain direction). It has a similar incommensurability to that observed in ortho-VIII and ortho-III samples, which have different dopings and oxygen orderings. Our results for ortho-II contrast with recent high-field NMR measurements, which suggest a commensurate wave vector along the a axis. We discuss the relationship between spin and charge correlations in YBa2Cu3O(y) and recent high-field quantum oscillation, NMR, and ultrasound experiments.

  16. X-Ray Diffraction Observations of a Charge-Density-Wave Order in Superconducting Ortho-II YBa2Cu3O6.54 Single Crystals in Zero Magnetic Field

    Science.gov (United States)

    Blackburn, E.; Chang, J.; Hücker, M.; Holmes, A. T.; Christensen, N. B.; Liang, Ruixing; Bonn, D. A.; Hardy, W. N.; Rütt, U.; Gutowski, O.; Zimmermann, M. v.; Forgan, E. M.; Hayden, S. M.

    2013-03-01

    X-ray diffraction measurements show that the high-temperature superconductor YBa2Cu3O6.54, with ortho-II oxygen order, has charge-density-wave order in the absence of an applied magnetic field. The dominant wave vector of the charge density wave is qCDW=(0,0.328(2),0.5), with the in-plane component parallel to the b axis (chain direction). It has a similar incommensurability to that observed in ortho-VIII and ortho-III samples, which have different dopings and oxygen orderings. Our results for ortho-II contrast with recent high-field NMR measurements, which suggest a commensurate wave vector along the a axis. We discuss the relationship between spin and charge correlations in YBa2Cu3Oy and recent high-field quantum oscillation, NMR, and ultrasound experiments.

  17. Neutron diffraction studies of magnetic ordering in superconducting ErNi2B2C and TmNi2B2C in an applied magnetic field

    DEFF Research Database (Denmark)

    Toft, Katrine Nørgaard

    along [110], the magnetic structure rotates a small angle of 0.5 degrees away from the symmetrydirection. TmNi2B2C: A magnetic field applied in the [100] direction suppresses the zero field magnetic structure QF = (0.094,0.094,0) (TN = 1.6 K), in favor of the Fermi surface nesting structure QN = (0......The field-induced magnetic structures of ErNi2B2C and TmNi2B2C in are especially interesting because the field suppresses the superconducting order parameter and therefore the magnetic properties can be studied while varying the strength ofsuperconductivity. ErNi2B2C: For magnetic fields along all...... three symmetry directions, the observed magnetic structures have a period corresponding to the Fermi surface nesting structure. The phase diagrams present all the observed magnetic structures.Two results remain unresolved: 1. When applying the magnetic field along [010], the minority domain (QNB = (0,Q...

  18. Reconstruction of Stress and Composition Profiles from X-ray Diffraction Experiments - How to Avoid Ghost Stresses?

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A.J.

    2004-01-01

    On evaluating lattice strain-depth or stress-depth profiles with X-ray diffraction, the variation of the information depth while combining various tilt angles,psi, in combination with lattice spacing gradients leads to artefacts,so-called ghost or fictitious stresses. X-ray diffraction lattice...... method for the evaluation of stress/strain and composition profiles, while minimising the risk for ghost stresses....

  19. Neutron diffraction study of anomalous high-field magnetic phases in TmNi2B2C

    DEFF Research Database (Denmark)

    Toft, K.N.; Abrahamsen, A.B.; Eskildsen, M.R.;

    2004-01-01

    .483,0,0), and Q(AII)=(0.496,0,0), all with the magnetic moment along the c axis. In zero and low fields the Tm 4f-moments order in a long wavelength transverse spin density wave with Q=Q(F). The magnetic Q(AI) structure is stabilized by an applied field of 1 T and a transition to Q(AII) is observed at 4 T......We present a (B,T)-phase diagram of the magnetic superconductor TmNi2B2C obtained by neutron scattering. The measurements were performed in magnetic fields up to 6 T applied along the crystalline a axis. The observed phases are characterized by three ordering vectors, Q(F)=(0.094,0.094,0),Q(AI)=(0.......90Yb0.10)Ni2B2C the Q(F)-->Q(AI) phase transition is also observed but at a larger transition field compared to the undoped compound. In (Tm0.85Yb0.15)Ni2B2C the Q(F) phase persists up to at least 1.8 T. The magnetic correlation length of the Q(AI) phase in TmNi2B2C measured parallel and perpendicular...

  20. Neutron diffraction and electrical transport studies on magnetic ordering in terbium at high pressures and low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Sarah [University of Alabama, Birmingham; Montgomery, Jeffrey M [University of Alabama, Birmingham; Tsoi, Georgiy [University of Alabama, Birmingham; Vohra, Yogesh [University of Alabama, Birmingham; Chesnut, Gary Neal [University of Alabama, Birmingham; Weir, S. T. [Lawrence Livermore National Laboratory (LLNL); Tulk, Christopher A [ORNL; Moreira Dos Santos, Antonio F [ORNL

    2013-01-01

    Neutron diffraction and electrical transport measurements have been carried out on the heavy rare-earth metal terbium at high pressures and low temperatures in order to elucidate the onset of ferromagnetic (FM) order as a function of pressure. The electrical resistance measurements show a change in slope as the temperature is lowered through the FM Curie temperature. The temperature of this FM transition decreases at a rate of-16.7 K/GPa up to a pressure of 3.6 GPa, at which point the onset of FM order is suppressed. The neutron diffraction measurements as a function of pressure at temperatures ranging from 90 to 290 K confirm that the change of slope in the resistance is associated with the FM ordering, since this occurs at pressures similar to those determined from the resistance results at these temperatures. A disappearance of FM ordering was observed as the pressure is increased above 3.6 GPa and is correlated with the phase transition from the ambient hexagonal close packed structure to an -Sm-type structure at high pressures.

  1. On the Sr1−xBaxFeO2F Oxyfluoride Perovskites: Structure and Magnetism from Neutron Diffraction and Mössbauer Spectroscopy

    Directory of Open Access Journals (Sweden)

    Crisanto A. García-Ramos

    2016-11-01

    Full Text Available Four oxyfluorides of the title series (x = 0.00, 0.25, 0.50, 0.75 have been stabilized by topotactic treatment of perovskite precursors Sr1−xBaxFeO3−δ prepared by soft-chemistry procedures, yielding reactive materials that can easily incorporate a substantial amount of F atoms at moderate temperatures, thus avoiding the stabilization of competitive SrF2 and BaF2 parasitic phases. XRD and Neutron Powder Diffraction (NPD measurements assess the phase purity and yield distinct features concerning the unit cell parameters’ variation, the Sr and Ba distribution, the stoichiometry of the anionic sublattice and the anisotropic displacement factors for O and F atoms. The four oxyfluorides are confirmed to be cubic in all of the compositional range, the unit cell parameters displaying Vergard’s law. All of the samples are magnetically ordered above room temperature; the magnetic structure is always G-type antiferromagnetic, as shown from NPD data. The ordered magnetic moments are substantially high, around 3.5 μB, even at room temperature (RT. Temperature-dependent Mössbauer data allow identifying Fe3+ in all of the samples, thus confirming the Sr1−xBaxFeO2F stoichiometry. The fit of the magnetic hyperfine field vs. temperature curve yields magnetic ordering TN temperatures between 740 K (x = 0.00 and 683 K (x = 0.75. These temperatures are substantially higher than those reported before for some of the samples, assessing for stronger Fe-Fe superexchange interactions for these specimens prepared by fluorination of citrate precursors in mild conditions.

  2. Magnetic helicity balance in the Sustained Spheromak Plasma Experiment

    Science.gov (United States)

    Stallard, B. W.; Hooper, E. B.; Woodruff, S.; Bulmer, R. H.; Hill, D. N.; McLean, H. S.; Wood, R. D.

    2003-07-01

    The magnetic helicity balance between the helicity input injected by a magnetized coaxial gun, the rate-of-change in plasma helicity content, and helicity dissipation in electrode sheaths and Ohmic losses have been examined in the Sustained Spheromak Plasma Experiment (SSPX) [E. B. Hooper, L. D. Pearlstein, and R. H. Bulmer, Nucl. Fusion 39, 863 (1999)]. Helicity is treated as a flux function in the mean-field approximation, allowing separation of helicity drive and losses between closed and open field volumes. For nearly sustained spheromak plasmas with low fluctuations, helicity balance analysis implies a decreasing transport of helicity from the gun input into the spheromak core at higher spheromak electron temperature. Long pulse discharges with continuously increasing helicity and larger fluctuations show higher helicity coupling from the edge to the spheromak core. The magnitude of the sheath voltage drop, inferred from cathode heating and a current threshold dependence of the gun voltage, shows that sheath losses are important and reduce the helicity injection efficiency in SSPX.

  3. Spectrometer magnet for experiment NA4 (deep inelastic muon scattering)

    CERN Multimedia

    1977-01-01

    This is one section of the toroidal-field spectrometer magnet of experiment NA4 (deep inelastic muon scattering), shown here during the installation period and later located in the North Area of the SPS. To see all 4 sections, select 7709201. Igor Savin from Dubna looks at what his lab had provided: the huge iron disks were machined at and provided by Dubna. Multi-Wire Proportional Chambers were installed in the gaps between the packs of 4 disks. When the beam from the SPS struck the target (to the right in this picture), the iron would quickly stop the hadronic shower, whilst the muons would go on, performing oscillations in the toroidal field. NA4 was a CERN-Dubna-Munich-Saclay (later also Bologna) collaboration, spokesman: Carlo Rubbia.

  4. Evolution of structure and local magnetic fields during crystallization of HITPERM glassy alloys studied by in situ diffraction and nuclear forward scattering of synchrotron radiation.

    Science.gov (United States)

    Miglierini, Marcel; Pavlovič, Márius; Procházka, Vít; Hatala, Tomáš; Schumacher, Gerhard; Rüffer, Rudolf

    2015-11-14

    Evolution of structure and local magnetic fields in (Fe(1-x)Co(x))76Mo8Cu1B15 (HITPERM) metallic glass ribbons with various amounts of Co (x = 0, 0.25, 0.5) were studied in situ using diffraction and nuclear forward scattering of synchrotron radiation. It was found that crystallization of all three glasses proceeds in two stages. In the first stage, bcc (Fe,Co) nanocrystals are formed, while in the second stage additional crystalline phases evolve. For all three glasses, the crystallization temperatures at the wheel side were found to be lower than at the air side of the ribbon. The crystallization temperatures were found to decrease with increasing Co content. The lattice parameters of the bcc nanocrystals decrease up to about 550 °C and then increase pointing to squeezing Mo atoms out of the nanograins or to interface effects between the nanocrystals and the glassy matrix. Nuclear forward scattering enabled separate evaluation of the contributions that stem from structurally different regions within the investigated samples including the newly formed nanocrystals and the residual amorphous matrix. Even minor Co content (x = 0.25) has a substantial effect not only upon the magnetic behaviour of the alloy but also upon its structure. Making use of hyperfine magnetic fields, it was possible to unveil structurally diverse positions of Fe atoms that reside in a nanocrystalline lattice with different numbers of Co nearest neighbours.

  5. Analysis of dijet events in diffractive ep interactions with tagged leading proton at the H1 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Polifka, Richard

    2011-08-15

    An inclusive dijet production in diffractive deep-inelastic scattering is measured. The diffractive selection is based on tagging of the leading proton in the Forward Proton Spectrometer. The statistics of events obtained during the HERA II running period (integrated luminosity of 156.7 pb{sup -1}) enables the measurement of jet final states with leading proton for the first time. The data cover the phase space of x{sub P}<0.1, vertical stroke t vertical stroke {<=}1.0 GeV{sup 2} and 4{<=} Q{sup 2} {<=}110 GeV{sup 2}. The dijet data are compared with the next to leading order predictions of the quantum chromodynamics (QCD). The phase space of diffractive dijets is in this analysis by factor of 3 in x{sub P} larger than in previous measurements. The QCD predictions based on the DGLAP parton evolution describe the measured data well even in a non-DGLAP enriched phase space where one on the jets goes into the region close to the direction of the outgoing proton. The measured single-differential cross sections are compared to several Monte Carlo models with different treatment of diffractive exchange implemented. (orig.)

  6. Thermal and magnetic anomalies of α-iron: an exploration by extended x-ray absorption fine structure spectroscopy and synchrotron x-ray diffraction

    Science.gov (United States)

    Boccato, Silvia; Sanson, Andrea; Kantor, Innokenty; Mathon, Olivier; Dyadkin, Vadim; Chernyshov, Dmitry; Carnera, Alberto; Pascarelli, Sakura

    2016-09-01

    The local structure and dynamics of α-iron have been investigated by extended x-ray absorption fine structure (EXAFS) spectroscopy and x-ray diffraction (XRD) in order to shed light on some thermal and magnetic anomalies observed in the last decades. The quantitative EXAFS analysis of the first two coordination shells reveals a peculiar local vibrational dynamics of α-iron: the second neighbor distance exhibits anharmonicity and vibrational anisotropy larger than the first neighbor distance. We search for possible distortions of the bcc structure to justify the unexplained magnetostriction anomalies of α-iron and provide a value for the maximum dislocation of the central Fe atom. No thermal anomalies have been detected from the current XRD data. On the contrary, an intriguing thermal anomaly at about 150 K, ascribed to a stiffening of the Fe-Fe bonds, was found by EXAFS.

  7. Computational modeling of joint U.S.-Russian experiments relevant to magnetic compression/magnetized target fusion (MAGO/MTF)

    Energy Technology Data Exchange (ETDEWEB)

    Sheehey, P.T.; Faehl, R.J.; Kirkpatrick, R.C.; Lindemuth, I.R. [Los Alamos National Lab., NM (United States)

    1997-12-31

    Magnetized Target Fusion (MTF) experiments, in which a preheated and magnetized target plasma is hydrodynamically compressed to fusion conditions, present some challenging computational modeling problems. Recently, joint experiments relevant to MTF (Russian acronym MAGO, for Magnitnoye Obzhatiye, or magnetic compression) have been performed by Los Alamos National Laboratory and the All-Russian Scientific Research Institute of Experimental Physics (VNIIEF). Modeling of target plasmas must accurately predict plasma densities, temperatures, fields, and lifetime; dense plasma interactions with wall materials must be characterized. Modeling of magnetically driven imploding solid liners, for compression of target plasmas, must address issues such as Rayleigh-Taylor instability growth in the presence of material strength, and glide plane-liner interactions. Proposed experiments involving liner-on-plasma compressions to fusion conditions will require integrated target plasma and liner calculations. Detailed comparison of the modeling results with experiment will be presented.

  8. High Magnetic field generation for laser-plasma experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pollock, B B; Froula, D H; Davis, P F; Ross, J S; Fulkerson, S; Bower, J; Satariano, J; Price, D; Glenzer, S H

    2006-05-01

    An electromagnetic solenoid was developed to study the effect of magnetic fields on electron thermal transport in laser plasmas. The solenoid, which is driven by a pulsed power system suppling 30 kJ, achieves magnetic fields of 13 T. The field strength was measured on the solenoid axis with a magnetic probe and optical Zeeman splitting. The measurements agree well with analytical estimates. A method for optimizing the solenoid design to achieve magnetic fields exceeding 20 T is presented.

  9. Synthetic Experiment Simulation of grating diffraction Based on MATLAB and VB%基于Matlab与VB的光栅衍射综合实验仿真

    Institute of Scientific and Technical Information of China (English)

    赵华芬; 孔德明

    2012-01-01

    Taking the grating diffraction as an example, the simulation program based on MATLAB is compiled, and then using the interfacing technology of DLL, combining MATLAB powerful function of scientific calculation and visualization function of Visual Basic, the optical experiments of grating diffraction, single slot diffraction, Young's double-slit interference and multi-beam interference are imitated vividly by changing the input parameters. The patterns of the experiment are delicate and distinct. It offers a new effective supplementary means for optical theory analysis and experiment teaching. In addition, it provides a new way for courseware design.%以光栅衍射为例,编写了基于Matlab的仿真程序.利用DLL接口技术,结合Matlab强大的科学计算功能以及Visual Basic的可视化功能,通过改变输入参数实现了对光栅衍射、单缝衍射、杨氏双缝干涉以及多光束干涉的光学实验进行生动形象的仿真模拟.实验结果的图样细致逼真,可为光学的理论分析和实验教学提供新的有效辅助手段,并为相关课件的设计提供了新的途径.

  10. Scaling experiments on a magnetically insulated thermionic vacuum switch

    Energy Technology Data Exchange (ETDEWEB)

    Eninger, J.E.; Vanderberg, B.H. [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Industrial Electrotechnology

    1994-12-31

    Magnetic insulation of the electron flow in a cylindrical thermionic vacuum diode has been proposed as a way to achieve a fast high-voltage high-power opening switch. The expected performance of this type of device can be derived from a set of basic scaling laws combined with empirical relationships obtained from experimental studies. Switch losses are mainly due to anode dissipation W{sub a}, which can be normalized to the transferred pulse energy. Leakage current and switch hold-off voltage depend on device geometry, materials, vacuum conditions etc and must be determined experimentally. For this purpose, the MX-1 experiment has been designed and operated. This device is basically a smooth-bore cylindrical magnetron with a 5 cm radius, 400 cm{sup 2} area thermionic dispenser cathode separated from the coaxial water-cooled anode by a few mm wide gap. This design allows pulsed operation at up to {approximately}100 kV, {approximately}4 kA and average power levels of {approximately}1 MW. The MX-1 switch is used as an opening switch to produce 1--2 {mu}s long square pulses from an inductive storage PFN. The current-voltage characteristics of the switch are determined as a function of the applied magnetic field and load condition. Plasma wave measurements are performed to investigate the stability of the electron flow. Results are summarized in the form of scaling diagrams for the important switch parameters, showing possible performance levels and physical and technical limitations identified as far in this work.

  11. Inclusive Hard Diffraction at HERA

    CERN Document Server

    Proskuryakov, Alexander

    2010-01-01

    Recent data from the H1 and ZEUS experiments on hard inclusive diffraction are discussed. Results of QCD analyses of the diffractive deep-inelastic scattering processes are reported. Predictions based on the extracted parton densities are compared to diffractive dijet measurements.

  12. Refinement of atomic and magnetic structures using neutron diffraction for synthesized bulk and nano-nickel zinc gallate ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Ata-Allah, S.S. [Reactor Physics Department, NRC, Atomic Energy Authority, P.O. Box 13759, Cairo (Egypt); Balagurov, A.M. [Frank Laboratory of Neutron Physics, JINR, 141980 Dubna, Moscow region (Russian Federation); Hashhash, A. [Reactor Physics Department, NRC, Atomic Energy Authority, P.O. Box 13759, Cairo (Egypt); Bobrikov, I.A. [Frank Laboratory of Neutron Physics, JINR, 141980 Dubna, Moscow region (Russian Federation); Hamdy, Sh. [Reactor Physics Department, NRC, Atomic Energy Authority, P.O. Box 13759, Cairo (Egypt)

    2016-01-15

    The parent NiFe{sub 2}O{sub 4} and Zn/Ga substituted spinel ferrite powders have been prepared by solid state reaction technique. As a typical example, the Ni{sub 0.7}Zn{sub 0.3}Fe{sub 1.5}Ga{sub 0.5}O{sub 4} sample has been prepared by sol–gel auto combustion method with the nano-scale crystallites size. X-ray and Mössbauer studies were carried out for the prepared samples. Structure and microstructure properties were investigated using the time-of-flight HRFD instrument at the IBR-2 pulsed reactor, at a temperatures range 15–473 K. The Rietveld refinement of the neutron diffraction data revealed that all samples possess cubic symmetry corresponding to the space group Fd3m. Cations distribution show that Ni{sup 2+} is a complete inverse spinel ion, while Ga{sup 3+} equally distributed between the two A and B-sublattices. The level of microstrains in bulk samples was estimated as very small while the size of coherently scattered domains is quite large. For nano-structured sample the domain size is around 120 Å.

  13. Asymptotic Analysis of Transverse Magnetic Multiple Scattering by the Diffraction Grating of Penetrable Cylinders at Oblique Incidence

    Directory of Open Access Journals (Sweden)

    Ömer Kavaklıoğlu

    2011-01-01

    Full Text Available We have presented a derivation of the asymptotic equations for transverse magnetic multiple scattering coefficients of an infinite grating of penetrable circular cylinders for obliquely incident plane electromagnetic waves. We have first deducted an “Ansatz” delineating the asymptotic behavior of the transverse magnetic multiple scattering coefficients associated with the most generalized condition of oblique incidence (Kavaklıoğlu, 2000 by exploiting Schlömilch series corresponding to the special circumstance that the grating spacing is much smaller than the wavelength of the incident electromagnetic radiation. The validity of the asymptotic equations for the aforementioned scattering coefficients has been verified by collating them with the Twersky's asymptotic equations at normal incidence. Besides, we have deduced the consequences that the asymptotic forms of the equations at oblique incidence acquired in this paper reduce to Twersky's asymptotic forms at normal incidence by expanding the generalized scattering coefficients at oblique incidence into an asymptotic series as a function of the ratio of the cylinder radius to the grating spacing.

  14. Photoelectron diffraction and holography: Some new directions

    Energy Technology Data Exchange (ETDEWEB)

    Fadley, C.S. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Davis, CA (United States). Dept. of Physics

    1993-08-01

    Photoelectron diffraction has by now become a versatile and powerful technique for studying surface structures, with special capabilities for resolving chemical and magnetic states of atoms and deriving direct structural information from both forward scattering along bond directions and back-scattering path length differences. Further fitting experiment to theory can lead to structural accuracies in the {plus_minus}0.03 ){Angstrom} range. Holographic inversions of such diffraction data also show considerable promise for deriving local three-dimensional structures around a given emitter with accuracies of {plus_minus}0.2--0.3 {Angstrom}. Resolving the photoelectron spin in some way and using circularly polarized radiation for excitation provide added dimensions for the study of magnetic systems and chiral experimental geometries. Synchrotron radiation with the highest brightness and energy resolution, as well as variable polarization, is crucial to the full exploitation of these techniques.

  15. Preliminary analysis of the MER magnetic properties experiment using a computational fluid dynamics model

    DEFF Research Database (Denmark)

    Kinch, K.M.; Merrison, J.P.; Gunnlaugsson, H.P.;

    2006-01-01

    Motivated by questions raised by the magnetic properties experiments on the NASA Mars Pathfinder and Mars Exploration Rover (MER) missions, we have studied in detail the capture of airborne magnetic dust by permanent magnets using a computational fluid dynamics (CFD) model supported by laboratory...

  16. The Magnetic Sentences Industry Game: A Competitive In-Class Experience of Business-Level Strategy

    Science.gov (United States)

    Casile, Maureen; Wheeler, Jane V.

    2005-01-01

    The Magnetic Sentences Industry Game is a high-energy in-class exercise designed to help students gain hands-on experience with setting, implementing, evaluating, and revising business-level strategy. Students compete in teams to create and market sentences using Magnetic Poetry (a product of Magnetic Poetry, Inc.). Revenues earned are highly…

  17. The Magnetic Sentences Industry Game: A Competitive In-Class Experience of Business-Level Strategy

    Science.gov (United States)

    Casile, Maureen; Wheeler, Jane V.

    2005-01-01

    The Magnetic Sentences Industry Game is a high-energy in-class exercise designed to help students gain hands-on experience with setting, implementing, evaluating, and revising business-level strategy. Students compete in teams to create and market sentences using Magnetic Poetry (a product of Magnetic Poetry, Inc.). Revenues earned are highly…

  18. Tools and Setups for Experiments with AC and Rotating Magnetic Fields

    Science.gov (United States)

    Ponikvar, D.

    2010-01-01

    A rotating magnetic field is the basis for the transformation of electrical energy to mechanical energy. School experiments on the rotating magnetic field are rare since they require the use of specially prepared mechanical setups and/or relatively large, three-phase power supplies to achieve strong magnetic fields. This paper proposes several…

  19. Diffraction to De-Diffraction

    CERN Document Server

    Tamari, V F

    2003-01-01

    De-diffraction (DD), a new procedure to totally cancel diffraction effects from wave-fields is presented, whereby the full field from an aperture is utilized and a truncated geometrical field is obtained, allowing infinitely sharp focusing and non-diverging beams. This is done by reversing a diffracted wave-fields' direction. The method is derived from the wave equation and demonstrated in the case of Kirchhoff's integral. An elementary bow-wavelet is described and the DD process is related to quantum and relativity theories.

  20. Non-diffractive waves

    CERN Document Server

    Hernandez-Figueroa, Hugo E; Recami, Erasmo

    2013-01-01

    This continuation and extension of the successful book ""Localized Waves"" by the same editors brings together leading researchers in non-diffractive waves to cover the most important results in their field and as such is the first to present the current state.The well-balanced presentation of theory and experiments guides readers through the background of different types of non-diffractive waves, their generation, propagation, and possible applications. The authors include a historical account of the development of the field, and cover different types of non-diffractive waves, including Airy

  1. Sr{sub 4}Ru{sub 6}ClO{sub 18}, a new Ru{sup 4+/5+} oxy-chloride, solved by precession electron diffraction: Electric and magnetic behavior

    Energy Technology Data Exchange (ETDEWEB)

    Roussel, Pascal, E-mail: pascal.roussel@ensc-lille.fr [Université Lille-Nord de France, UCCS—Unité de Catalyse et Chimie du Solide, UMR CNRS 8181, Ecole Nationale Supérieure de Chimie de Lille, 59652 Villeneuve d’Ascq (France); Palatinus, Lukas [Institute of Physics of the Czech Academy of Sciences, Department of Structure Analysis, Na Slovance 2, 182 21 Praha 8 (Czech Republic); Belva, Frédéric; Daviero-Minaud, Sylvie; Mentre, Olivier; Huve, Marielle [Université Lille-Nord de France, UCCS—Unité de Catalyse et Chimie du Solide, UMR CNRS 8181, Ecole Nationale Supérieure de Chimie de Lille, 59652 Villeneuve d’Ascq (France)

    2014-04-01

    The crystal structure of Sr{sub 4}Ru{sub 6}ClO{sub 18}, a new Ru{sup 4+/5+} oxo-chloride, has been determined from Precession Electron Diffraction (PED) data acquired on a nanocrystal in a transmission electron microscope using the technique of electron diffraction tomography. This approach is described in details following a pedagogic route and a systematic comparison is made of this rather new method with other experimental methods of electron diffraction, and with the standard single crystal X-ray diffraction technique. Both transport and magnetic measurements, showed a transition at low temperature that may be correlated to Ru{sup 4+}/Ru{sup 5+} charge ordering. - Graphical abstract: Structure of Sr{sub 4}Ru{sub 6}ClO{sub 18}, determined using Precession Electron Diffraction data. - Highlights: • Structure of Sr{sub 4}Ru{sub 6}ClO{sub 18} was solved ab initio using precession electron diffraction. • This was done both on a nanometric sample and on a micrometric one. • Different type of experimental methods of electron diffraction are compared. • Single crystal X-ray diffraction was used to confirm the results. • Transport properties were characterized and show “exotic” behavior.

  2. Two Novel μ-Oxo Diiron(Ⅲ) Schiff Base Complexes: X-ray Diffraction Analyses, IR, UV-Vis, CD spectra, Magnetic Susceptibility and Electrochemistry

    Institute of Scientific and Technical Information of China (English)

    阮文娟; 胡国航; 王树军; 田建华; 王庆伦; 朱志昂

    2005-01-01

    The novel μ-oxo diiron(Ⅲ) Schiff base complexes, {[Fe(tbusalphn)]2(μ-O)} (1) [tbusalphn=N,N'-o-pheny-lenebis(3,5-di-tert-butylsalicylideneiminato)] and { [Fe(R,R-salchxn)]2(μ-O)} (2) [R,R-salchxn=N,N'-R,R-cyclo-hexanebis(salicylideneiminato)] have been synthesized and characterized by elemental analyses, spectroscopy,magnetic susceptibility, electrochemical measurements and X-ray diffraction techniques. X-my analyses revealed that the complex 1-CH3OH has nearly linear Fe-O-Fe angle of 176.5(2)° due to their steric crowding of ligands owing bulky substitute group, while fairly bent Fe-O-Fe angle was allowed by the reduced steric crowding of the ligands in 2-CaH6N2-0.5C2H5OH [149.6(1)°]. FT-IR, UV-Vis, CD spectra, magnetic susceptibility and cyclic voltammogram (CV) of complexes 1 and 2 have been further investigated.

  3. The history of IFMFC - The accumulated knowledge and experience of the magnetic force control with IFMFC

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Tsueo [Tokyo Metropolitan University, Tokyo (Japan)

    2016-03-15

    The history of IFMFC (International Forum on Magnetic Force Control) shows the usefulness of the magnetic force control in the fields of the environment and material resource in Japan, Korea and China. The IFMFC started in 2010 and has been organized in every year. This paper shows the application of the magnetic force control in each countries with the accumulated knowledge and experience of the magnetic force control with IFMFC.

  4. Nuclear magnetic resonance experiments with dc SQUID amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Heaney, M.B. (California Univ., Berkeley, CA (USA). Dept. of Physics Lawrence Berkeley Lab., CA (USA))

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting QUantum Interference Devices) with Nb/Al{sub 2}O{sub 3}/Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 {times} 10{sup 17} in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO{sub 3} crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies.

  5. Nuclear magnetic resonance experiments with DC SQUID amplifiers

    Science.gov (United States)

    Heaney, M. B.

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting Quantum Interference Devices) with Nb/Al2O3/Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 x 10(exp 17) in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO3 crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies.

  6. Calculating cellulose diffraction patterns

    Science.gov (United States)

    Although powder diffraction of cellulose is a common experiment, the patterns are not widely understood. The theory is mathematical, there are numerous different crystal forms, and the conventions are not standardized. Experience with IR spectroscopy is not directly transferable. An awful error, tha...

  7. Magnetic helicity in stellar dynamos new numerical experiments

    CERN Document Server

    Brandenburg, A; Subramanian, K

    2002-01-01

    The theory of large scale dynamos is reviewed with particular emphasis on the problem of magnetic helicity conservation in the presence of closed and open boundaries. It is concluded that in solar and stellar large scale dynamos the production and destruction of magnetic helicity during one cycle may still be accomplished by ordinary Spitzer resistivity. This is mainly because of geometric effects causing significant magnetic helicity cancellation on each hemisphere, but also partly because the generation of toroidal field by shear does not involve the production of magnetic helicity. A number of alternatives are discussed and dismissed. These include open boundaries which lead to preferential loss of large scale magnetic helicity together with large scale magnetic fields. It is also shown that artificially induced losses of small scale field do not accelerate the production of large scale (poloidal) field. In fact, resistively limited evolution towards saturation is also found at intermediate scales before t...

  8. RAT magnet experiment on the Mars Exploration Rovers: Spirit and Opportunity beyond sol 500

    DEFF Research Database (Denmark)

    Leer, Kristoffer; Goetz, Walter; Chan, Marjorie A.;

    2011-01-01

    The Rock Abrasion Tool (RAT) magnet experiment on the Mars Exploration Rovers was designed to collect dust from rocks ground by the RAT of the two rovers on the surface of Mars. The dust collected on the magnets is now a mixture of dust from many grindings. Here the new data from the experiment a...

  9. MAGNETIC STRIPS TO SIMULATE LAYERED BRITTLE SOLIDS IN CLEAVAGE AND FRACTURE EXPERIMENTS

    Institute of Scientific and Technical Information of China (English)

    Francisco G.Emmerich; Alfredo G.Cunha; Carlos M.A.Girelli; Arnobio I.Vassem

    2008-01-01

    A characteristic of the fracture and cleavage experiments is that they are usually intrinsically destructive.Cracks do not completely heal in an unstressed system,even in crystals such as mica.Here,we used magnetic solids composed of magnetic strips for the non-destructive cleavage and brittle fracture experiments.Between the magnetic strips materials with different mechanical characteristics can be inserted,such as Teflon or foam strips,to change the mechanical properties of the solid.For the cleavage experiments,we developed an apparatus where parameters such as the main involved force can be measured easily.By inserting flaws,the magnetic solid can be used in dynamic fracture experiments,with the advantages of simulating macroscopically a non-destructive experiment in an easier way,that happen in real materials with much higher velocities.The apparatus and the used magnetic solid may be useful for demonstrations of fractures in classes.

  10. Real-time X-ray diffraction imaging for semiconductor wafer metrology and high temperature in situ experiments

    Energy Technology Data Exchange (ETDEWEB)

    Danilewsky, A.N.; Wittge, J.; Hess, A.; Croell, A. [Kristallographie, Institut fuer Geowissenschaften, Universitaet Freiburg (Germany); Rack, A. [European Synchrotron Radiation Facility, Grenoble (France); Allen, D.; McNally, P. [Research Institute for Networks and Communications Engineering, Dublin City University, Dublin (Ireland); Santos Rolo, T. dos; Vagovic, P.; Baumbach, T. [Institut fuer Synchrotronstrahlung, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Garagorri, J.; Elizalde, M.R. [CEIT and Tecnun (University of Navarra), San Sebastian (Spain); Tanner, B.K. [Department of Physics, Durham University (United Kingdom)

    2011-11-15

    We describe a rapid digital system for X-ray diffraction imaging and demonstrate its application to the real-time identification of edge defects in a silicon wafer that had been subjected to rapid thermal annealing. The application of the system to the in situ study of slip nucleation at the location of mechanical wafer defects, indents and a thermocouple, and the subsequent dislocation dynamics is presented. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Evolution of Cu-Zn-Si oxide catalysts in the course of reduction and reoxidation as studied by in situ X-ray diffraction analysis, transmission electron microscopy, and magnetic susceptibility methods

    NARCIS (Netherlands)

    Minyukova, T.P.; Shtertser, N.V.; Khassin, A.A.; Plyasova, L.M.; Kustova, G.N.; Zaikovskii, V.I.; Shvedenkov, Y.G.; Baronskaya, N.A.; van den Heuvel, J.C.; Kuznetsova, A.V.; Davydova, L.P.; Yur'eva, T.M.

    2008-01-01

    The reduced and reoxidized Cu-Zn-Si oxide catalysts as layered copper-zinc hydroxo silicates with the zincsilite structure were studied using in situ and ex situ X-ray diffraction analysis, transmission electron microscopy, and the temperature dependence of magnetic susceptibility. The catalysts wer

  12. Reconnection experiments with 3D magnetic nulls in different topologies

    Science.gov (United States)

    Vrublevskis, A.; Egedal, J.; Le, A.

    2012-10-01

    Magnetic reconnection has been predominantly investigated in two dimensions. However, depending on the topology and geometry of the magnetic field, a rich collection of magnetic reconnection scenarios is possible in 3D including reconnection at magnetic nulls. At the Versatile Toroidal Facility (VTF) we have implemented a new magnetic geometry with a pair of 3D null points in the background toroidal field. We form a flux rope along the background field and observe it to rapidly restructure and rewire as the nulls develop. We can adjust the topology of the configuration from one where a field line connects the nulls to one where the nulls are no longer linked. A suit of diagnostics will be deployed and results presented for how the topology affects the dynamics of the flux rope.

  13. SINGLE CRYSTAL NEUTRON DIFFRACTION.

    Energy Technology Data Exchange (ETDEWEB)

    KOETZLE,T.F.

    2001-03-13

    Single-crystal neutron diffraction measures the elastic Bragg reflection intensities from crystals of a material, the structure of which is the subject of investigation. A single crystal is placed in a beam of neutrons produced at a nuclear reactor or at a proton accelerator-based spallation source. Single-crystal diffraction measurements are commonly made at thermal neutron beam energies, which correspond to neutron wavelengths in the neighborhood of 1 Angstrom. For high-resolution studies requiring shorter wavelengths (ca. 0.3-0.8 Angstroms), a pulsed spallation source or a high-temperature moderator (a ''hot source'') at a reactor may be used. When complex structures with large unit-cell repeats are under investigation, as is the case in structural biology, a cryogenic-temperature moderator (a ''cold source'') may be employed to obtain longer neutron wavelengths (ca. 4-10 Angstroms). A single-crystal neutron diffraction analysis will determine the crystal structure of the material, typically including its unit cell and space group, the positions of the atomic nuclei and their mean-square displacements, and relevant site occupancies. Because the neutron possesses a magnetic moment, the magnetic structure of the material can be determined as well, from the magnetic contribution to the Bragg intensities. This latter aspect falls beyond the scope of the present unit; for information on magnetic scattering of neutrons see Unit 14.3. Instruments for single-crystal diffraction (single-crystal diffractometers or SCDs) are generally available at the major neutron scattering center facilities. Beam time on many of these instruments is available through a proposal mechanism. A listing of neutron SCD instruments and their corresponding facility contacts is included in an appendix accompanying this unit.

  14. Diffractive optical elements and quasioptical schemes for experiments on a high-power terahertz free-electron laser

    Science.gov (United States)

    Vinokurov, N. A.; Zhigach, S. A.; Knyazev, B. A.; Konysheva, A. V.; Kulipanov, G. N.; Merzhievsky, L. A.; Polskikh, I. A.; Cherkassky, V. S.

    2007-10-01

    We have developed reflective diffraction optical elements (DOE) for focusing monochromatic coherent radiation of 400 W terahertz Novosibirsk free-electron laser (FEL). Operational characteristics of two modifications of the refractive kinoform lenses were studied. Quasioptical Toepler system with terahertz radiation recording by a thermosensitive luminescent screen was fabricated for the examination of film and solid deformation. A system for real-time terahertz radioscopy of objects with image recording with a microbolometer matrix (MBM) was fabricated. Images of objects illuminated with a plane wave or diffuse radiation were studied with the MBM. It was shown that the speckle pattern, which appears in the second case, can be averaged by means of the scatterer rotation.

  15. Advanced quantitative magnetic nondestructive evaluation methods - Theory and experiment

    Science.gov (United States)

    Barton, J. R.; Kusenberger, F. N.; Beissner, R. E.; Matzkanin, G. A.

    1979-01-01

    The paper reviews the scale of fatigue crack phenomena in relation to the size detection capabilities of nondestructive evaluation methods. An assessment of several features of fatigue in relation to the inspection of ball and roller bearings suggested the use of magnetic methods; magnetic domain phenomena including the interaction of domains and inclusions, and the influence of stress and magnetic field on domains are discussed. Experimental results indicate that simplified calculations can be used to predict many features of these results; the data predicted by analytic models which use finite element computer analysis predictions do not agree with respect to certain features. Experimental analyses obtained on rod-type fatigue specimens which show experimental magnetic measurements in relation to the crack opening displacement and volume and crack depth should provide methods for improved crack characterization in relation to fracture mechanics and life prediction.

  16. Magnetic MAX phases from theory and experiments; a review

    Science.gov (United States)

    Ingason, A. S.; Dahlqvist, M.; Rosen, J.

    2016-11-01

    This review presents MAX phases (M is a transition metal, A an A-group element, X is C or N), known for their unique combination of ceramic/metallic properties, as a recently uncovered family of novel magnetic nanolaminates. The first created magnetic MAX phases were predicted through evaluation of phase stability using density functional theory, and subsequently synthesized as heteroepitaxial thin films. All magnetic MAX phases reported to date, in bulk or thin film form, are based on Cr and/or Mn, and they include (Cr,Mn)2AlC, (Cr,Mn)2GeC, (Cr,Mn)2GaC, (Mo,Mn)2GaC, (V,Mn)3GaC2, Cr2AlC, Cr2GeC and Mn2GaC. A variety of magnetic properties have been found, such as ferromagnetic response well above room temperature and structural changes linked to magnetic anisotropy. In this paper, theoretical as well as experimental work performed on these materials to date is critically reviewed, in terms of methods used, results acquired, and conclusions drawn. Open questions concerning magnetic characteristics are discussed, and an outlook focused on new materials, superstructures, property tailoring and further synthesis and characterization is presented.

  17. Magnetic MAX phases from theory and experiments; a review.

    Science.gov (United States)

    Ingason, A S; Dahlqvist, M; Rosen, J

    2016-11-02

    This review presents MAX phases (M is a transition metal, A an A-group element, X is C or N), known for their unique combination of ceramic/metallic properties, as a recently uncovered family of novel magnetic nanolaminates. The first created magnetic MAX phases were predicted through evaluation of phase stability using density functional theory, and subsequently synthesized as heteroepitaxial thin films. All magnetic MAX phases reported to date, in bulk or thin film form, are based on Cr and/or Mn, and they include (Cr,Mn)2AlC, (Cr,Mn)2GeC, (Cr,Mn)2GaC, (Mo,Mn)2GaC, (V,Mn)3GaC2, Cr2AlC, Cr2GeC and Mn2GaC. A variety of magnetic properties have been found, such as ferromagnetic response well above room temperature and structural changes linked to magnetic anisotropy. In this paper, theoretical as well as experimental work performed on these materials to date is critically reviewed, in terms of methods used, results acquired, and conclusions drawn. Open questions concerning magnetic characteristics are discussed, and an outlook focused on new materials, superstructures, property tailoring and further synthesis and characterization is presented.

  18. Crystal structure and magnetic properties of Mo-substituted 'Ba{sub 2}(Fe,W){sub 2}O{sub 6}' double-perovskites: a synchrotron diffraction, magnetization and Moessbauer study

    Energy Technology Data Exchange (ETDEWEB)

    Rammeh, N.; Bramnik, K.G.; Ehrenberg, H.; Stahl, B.; Fuess, H.; Cheikh-Rouhou, A

    2004-01-28

    Synchrotron diffraction and Moessbauer spectroscopy on Ba{sub 2}(Fe,W){sub 2}O{sub 6} confirmed an Fe excess in this double-perovskite, better described as Ba{sub 2}Fe(Fe{sub x}W{sub 1-x})O{sub 6-{delta}} with x=0.2. The crystal structure is cubic (Fm3-bar m) down to 10 K, and a recently reported tetragonal structure of Ba{sub 2}FeWO{sub 6} is critically reviewed. Magnetic properties of Ba{sub 2}(Fe,W{sub 1-x}Mo{sub x}){sub 2}O{sub 6} compounds were studied by SQUID measurements and revealed weak ferromagnetism at low temperatures, and T{sub C} increases with more substitution of Mo for W.

  19. Tools and setups for experiments with AC and rotating magnetic fields

    Science.gov (United States)

    Ponikvar, D.

    2010-09-01

    A rotating magnetic field is the basis for the transformation of electrical energy to mechanical energy. School experiments on the rotating magnetic field are rare since they require the use of specially prepared mechanical setups and/or relatively large, three-phase power supplies to achieve strong magnetic fields. This paper proposes several experiments and describes setups and tools which are easy to obtain and work with. Free software is offered to generate the required signals by a personal computer. The experiments can be implemented in introductory physics courses on electromagnetism for undergraduates or specialized courses at high schools.

  20. Quasi-static magnetic measurements to predict specific absorption rates in magnetic fluid hyperthermia experiments

    OpenAIRE

    Coral, DF; Zelis, PM; de Sousa, ME; Muraca, D.; Lassalle, V.; Nicolas, P.; Ferreira,ML.; van Raap, MBF

    2014-01-01

    In this work, the issue on whether dynamic magnetic properties of polydispersed magnetic colloids modeled using physical magnitudes derived from quasi-static magnetic measurement can be extrapolated to analyze specific absorption rate data acquired at high amplitudes and frequencies of excitation fields is addressed. To this end, we have analyzed two colloids of magnetite nanoparticles coated with oleic acid and chitosan in water displaying, under a radiofrequency field, high and low specific...

  1. Pump-probe SAXS experiments on ultrafast demagnetization of magnetic multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Pfau, B.; Schaffert, S.; Mohanty, J.; Geilhufe, J.; Flewett, S.; Eisebitt, S. [IOAP, Technische Universitaet Berlin (Germany); Buettner, F. [IOAP, Technische Universitaet Berlin (Germany); Paul Scherrer Institut, Villigen (Switzerland); Mueller, L.; Gutt, C.; Al-Shemmary, A.; Duesterer, S.; Redlin, H.; Gruebel, G. [HASYLAB, DESY, Hamburg (Germany); Vodungbo, B. [ENSTA ParisTech, Ecole Polytechnique, Palaiseau (France); Luening, J. [Universite Pierre et Marie Curie, Paris (France); Stickler, D.; Froemter, R.; Oepen, H.P. [Universitaet Hamburg (Germany); Schlotter, W.F. [LCLS, SLAC, Menlo Park (United States)

    2011-07-01

    We have investigated the ultrafast optical demagnetization of domain patterns in magnetic multilayers with perpendicular magnetic anisotropy in an infrared-pump x-ray-probe experiment. As a probe we used small angle x-ray scattering which, via x-ray magnetic circular dichroism at the Co M-edge, allows us to simultaneously obtain information on the magnitude of the local magnetization and the characteristic length scale of the magnetic domains. The free-electron laser source FLASH at Hamburg was tuned to deliver {lambda}=20.9nm x-ray pulses of approx. 25 fs duration which were synchronized to an infrared fs laser for pump-probe experiments with sub-ps time resolution. In addition to ultrafast demagnetization, we observe sub-ps structural changes of the magnetic domain configuration. Models to explain this ultrafast structural change will be discussed.

  2. Reconnection Experiments with Flux Ropes near 3D Magnetic Nulls

    Science.gov (United States)

    Vrublevskis, A.; Egedal, J.; Le, A.

    2012-12-01

    Magnetic reconnection has been predominantly investigated in two dimensions. However, depending on the topology and geometry of the magnetic field, a rich collection of magnetic reconnection scenarios is possible in 3D including reconnection at magnetic nulls. Nulls have been reported in the solar corona [1] and in Earth's magnetosphere [2], yet there are a limited number of laboratory observations. At the Versatile Toroidal Facility (VTF) we have implemented a new magnetic geometry with a pair of 3D null points in the background toroidal field. We form a flux rope along the background field and observe it to rapidly restructure and rewire as the nulls develop. We can adjust the topology of the configuration from one where a field line connects the nulls to one where the nulls are no longer linked. A suit of diagnostics will be deployed and results presented for the dynamics of the flux rope. [1] Fletcher et al., Astrophys. J. 554, 451(2001) [2] Xiao et al., Nat. Phys. 2, 478 (2006)

  3. Backhopping in magnetic tunnel junctions: Micromagnetic approach and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Frankowski, Marek, E-mail: wsong@unb.ca; Skowroński, Witold; Czapkiewicz, Maciej; Stobiecki, Tomasz

    2015-01-15

    Micromagnetic simulations of Current Induced Magnetization Switching (CIMS) loops in CoFeB/MgO/CoFeB exchange-biased Magnetic Tunnel Junctions (MTJ) are discussed. Our model uses the Landau–Lifshitz–Gilbert equation with the Slonczewski's Spin-Transfer-Torque (STT) component. The current density for STT is calculated from the applied bias voltage and tunnel magnetoresistance which depends on the local magnetization vectors arrangement. We take into account the change in the anti-parallel state resistance with increasing bias voltage. Using such model we investigate influence of the interlayer exchange coupling, between free and reference layers across the barrier, on the backhopping effect in anti-parallel to parallel switching. We compare our simulated CIMS loops with the experimental data obtained from MTJs with different MgO barrier thicknesses. - Highlights: • We model Current Induced Magnetization Switching in magnetic tunnel junctions. • We investigate interlayer exchange coupling influence on backhopping effect. • Experimental results are reproduced with good qualitative agreement. • Ferromagnetic coupling decreases backhopping occurrence probability.

  4. Search for GUT magnetic monopoles and nuclearites with the MACRO experiment

    CERN Document Server

    Ambrosio, M; Auriemma, G; Bakari, D; Baldini, A; Barbarino, G C; Barish, B C; Battistoni, G; Becherini, Y; Bellotti, R; Bemporad, C; Bernardini, P; Bilokon, H; Bloise, C; Bower, C; Brigida, M; Bussino, S; Cafagna, F; Calicchio, M; Campana, D; Carboni, M; Caruso, R; Cecchini, S; Cei, F; Chiarella, V; Chiarusi, T; Choudhary, B C; Coutu, S; Cozzi, M; De Cataldo, G; De Marzo, C; De Mitri, I; De Vincenzi, M; Dekhissi, H; Derkaoui, J; Di Credico, A; Erriquez, O; Favuzzi, C; Forti, C; Fusco, P; Giacomelli, G; Giannini, G; Giglietto, N; Giorgini, M; Grassi, M; Grillo, A; Guarino, F; Gustavino, C; Habig, A; Hanson, K; Heinz, R; Katsavounidis, E; Katsavounidis, I; Kearns, E; Kim, H; Kumar, A; Kyriazopoulou, S; Lamanna, E; Lane, C; Larocci, E; Levin, D S; Lipari, P; Longley, N P; Longo, M J; Loparco, F; Maarou, F; Mancarella, G; Mandrioli, G; Manzoor, S; Margiotta, A; Marini, A; Martello, D; Marzari-Chiesa, A; Matteuzzi, D; Mazziotta, M N; Michael, D G; Monacelli, P; Montaruli, T; Monteno, M; Mufson, S; Musser, J; Nicolò, D; Nolty, R; Orth, C; Osteria, G; Palamara, O; Patera, V; Patrizii, L; Pazzi, R; Peck, C W; Perrone, L; Petrera, S; Pistilli, P; Popa, V; Rainó, A; Reynoldson, J; Ronga, F; Rrhioua, A; Satriano, C; Scapparone, E; Scholberg, K; Sciubba, A; Serra, P; Sioli, M; Sirri, G; Sitta, M; Spinelli, P; Spinetti, M; Spurio, M; Steinberg, R; Stone, J L; Sulak, L R; Surdo, A; Tarle, G; Togo, V; Vakili, M; Walter, C W; Webb, R; 10.1016/S1350-4487(03)00140-9

    2003-01-01

    We present the final results obtained by the MACRO experiment in the search for GUT magnetic monopoles and nuclearites. Several searches were performed with different subdetectors, i.e. scintillation counters, limited streamer tubes and nuclear track detectors. No magnetic monopole or nuclearite candidates were found. The MACRO upper limit to the local flux of GUT magnetic monopoles is at the level of 1.4*10/sup -16/ cm/sup -2/s/sup -1/sr/sup -1/.

  5. Experiments on second- and third-harmonic generation from magnetic metamaterials.

    Science.gov (United States)

    Klein, Matthias W; Wegener, Martin; Feth, Nils; Linden, Stefan

    2007-04-16

    Photonic metamaterials could provide optical nonlinearities far exceeding those of natural substances due to the combined action of (magnetic) resonances and local-field enhancements. Here, we present our experiments on second- and third-harmonic generation from magnetic metamaterials composed of nanoscale gold split-ring resonators and from control samples for excitation with 170-fs pulses centered at 1.5-microm wavelength. The strongest nonlinear signals are found for resonances with magnetic-dipole character.

  6. Direct methods in photoelectron diffraction; experiences and lessons learnt based on the use of the projection method

    Energy Technology Data Exchange (ETDEWEB)

    Woodruff, D.P. [Physics Department, University of Warwick, Coventry (United Kingdom); Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin (Germany); Baumgaertel, P.; Hoeft, J.T.; Kittel, M.; Polcik, M. [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Berlin (Germany)

    2001-11-26

    As part of a programme of full quantitative adsorbate structure determinations on surfaces using scanned-energy-mode photoelectron diffraction (PhD) combined with multiple-scattering simulations, direct data-inversion methods based on Fourier transforms and the so-called projection method have been tested on experimental data from more than 30 adsorbate/substrate systems. The results highlight both strengths and weaknesses, many of which are likely to be generic in the use of direct methods. The most obvious feature is the reduced value of the methods for systems involving low emitter site symmetry or multiple-site occupation, but some specific problems attributed to the elastic scattering cross-section 'signatures' of different elemental species and cases in which multiple scattering proves to be especially important are also discussed. A combination of these problems in a particular system can lead to complete failure, although even in these cases the results are unlikely to be actively misleading as regards the correct structure. (author)

  7. Analysis and experiment of eddy current loss in Homopolar magnetic bearings with laminated rotor cores

    Science.gov (United States)

    Jinji, Sun; Dong, Chen

    2013-08-01

    This paper analyses the eddy current loss in Homopolar magnetic bearings with laminated rotor cores produced by the high speed rotation in order to reduce the power loss for the aerospace applications. The analytical model of rotational power loss is proposed in Homopolar magnetic bearings with laminated rotor cores considering the magnetic circuit difference between Homopolar and Heteropolar magnetic bearings. Therefore, the eddy current power loss can be calculated accurately using the analytical model by magnetic field solutions according to the distribution of magnetic fields around the pole surface and boundary conditions at the surface of the rotor cores. The measurement method of rotational power loss in Homopolar magnetic bearing is proposed, and the results of the theoretical analysis are verified by experiments in the prototype MSCMG. The experimental results show the correctness of calculation results.

  8. Interference and Diffraction Phenomena of Young's Double Slit Experiment%杨氏双缝实验中的干涉与衍射现象

    Institute of Scientific and Technical Information of China (English)

    王筠; 吉紫鹃; 肖鹏程

    2012-01-01

    This article shows the interference fringe observed in the Young's double slit interference experiment is actually located in the single-slit diffraction center of the stripe region.Taken together these two experiments in practical work,students in this process can understand clearly the inseparable relationship between the single-slit diffraction and double slit interference.This helps students to apply theoretical knowledge to practice,learn and use,promoting the improvement of students' theoretical level.%杨氏双缝干涉实验中观测的干涉条纹实际上是位于单缝衍射中央明条纹区域内。实际工作中可以将这两个实验综合起来,学生在这个过程中可以清楚单缝衍射与双缝干涉之间的不可分离的关系,有助于学生将理论知识应用于实际,活学活用,促进学生理论水平的提高。

  9. Improved magnetization alignment schemes for spin-lock relaxation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, D. Flemming; Kay, Lewis E. [University of Toronto, Departments of Medical Genetics, Biochemistry and Chemistry (Canada)], E-mail: kay@pound.med.utoronto.ca

    2007-04-15

    A pair of pulse schemes that spin-lock magnetization efficiently are presented. The design of the sequences benefited from a particularly simple relation that is derived describing to first order the evolution of any magnetization component due to the application of an off-resonance 90{sup o} pulse. The sequences are shown theoretically and experimentally to significantly outperform the 90{sup o}-delay-90{sup o} element that is often used in current applications. It is shown that alignment of magnetization to within 1{sup o} of the effective field can be obtained over a bandwidth extending between [-{omega}{sub SL}, {omega}{sub SL}], where {omega}{sub SL} is the strength of the spin-lock field using a simple scheme that is an order of magnitude shorter than an adiabatic pulse that might also be used for a similar purpose.

  10. Overview of the magnetic properties experiments onboard the two Mars Exploration Rovers, Spirit and Opportunity

    Science.gov (United States)

    Leer, K.; Bertelsen, P.; Goetz, W.; Hviid, S. F.; Madsen, D. E.; Madsen, M. B.; Olsen, M.; The, A.

    2007-05-01

    The two Mars Exploration Rovers, Spirit and Opportunity, are each equipped with seven magnets designed for three different purposes: 1. The Filter and Capture magnets collect dust from the atmosphere. The dust can be investigated by the science instruments on the robotic arm and imaged by the Panoramic Camera. Analyzes of the dust shows that the magnetic component in the martian dust is magnetite, hematite together with paramagnetic and possibly superparamagnetic compounds is responsible for the yellowish color of the dust and the presence of olivine shows that the dust is formed without any appreciable presence of water. 2. The ring shaped Sweep magnet is design to detect non-magnetic particles. The experiment has been negative so far, showing that all particles must be composite and magnetic. This experience has been used to design a new camera calibration target for the Phoenix 2007, the sweep effect significantly preventing the calibration target to get dusty during the mission. 3. The Rock Abrasion Tool magnets are design to support the Mössbauer measurements on rocks giving additional information about the magnetic minerals contained in rocks. We here report on the results from the rovers and the neer future prospective for magnetic properties experiments on Mars.

  11. Neutron diffraction studies of the magnetic ordering in the spinel oxide system Mg{sub x}Co{sub 1-x}Cr{sub x}Fe{sub 2-x}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Yunus, S.M. [Institute of Nuclear Science and Technology, Atomic Energy Research Establishment, G.P.O. Box 3787, Dhaka 1000 (Bangladesh)], E-mail: smy133@yahoo.com; Yamauchi, Hiroki [Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Zakaria, A.K.M. [Institute of Nuclear Science and Technology, Atomic Energy Research Establishment, G.P.O. Box 3787, Dhaka 1000 (Bangladesh); Igawa, Naoki; Hoshikawa, Akinori [Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan); Haga, Yoshinori [Advanced Science Research Center, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1195 (Japan); Ishii, Yoshinobu [Quantum Beam Science Directorate, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195 (Japan)

    2008-05-08

    Neutron diffraction studies were performed on the spinel oxide system Mg{sub x}Co{sub 1-x}Cr{sub x}Fe{sub 2-x}O{sub 4} (x = 0.0, 0.25, 0.50, 0.75 and 1.0) as a function of temperature. Presence of magnetic long-range order at low temperatures was confirmed from the evolution of Bragg reflections with the decrease of temperature. Magnetic structural properties were determined from the Rietveld analysis of neutron diffraction data recorded in the temperature range 10-810 K. Sublattice and net magnetic moments for various compositions at various temperatures were found out from the analysis. The transition temperatures were also determined for all the compositions. A decreasing ferrimagnetic order with increasing substitution was revealed from the decreasing ordered sublattice moments. Huge diffuse signals around the 111 Bragg diffraction line were observed in the neutron patterns of the composition x = 1.0 below the Curie temperature indicating the existence of magnetic spin clusters. Hysteresis and low field dc magnetization measurements were done on the compositions x = 0.75 and 1.0. Thermo-magnetic irreversibility in the zero-field cooled and field cooled magnetization together with a shallow transition below Curie temperature was also observed. The various observations suggest a canted ferrimagnetic ordering in the composition range x {<=} 0.75 and a semi-spin glass like behavior at x = 1.0. A super-paramagnetic behavior below the paramagnetic state is also suggestive from the observed features.

  12. Investigation of LaMn{sub 2-x}Fe{sub x}Si{sub 2} (0-bar x-bar 1.2) by magnetic measurements and neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Dincer, I. [Department of Engineering Physics, Faculty of Engineering, Ankara University, TR-06100 Besevler-Ankara (Turkey)]. E-mail: idincer@eng.ankara.edu.tr; Elmali, A. [Department of Engineering Physics, Faculty of Engineering, Ankara University, TR-06100 Besevler-Ankara (Turkey); Elerman, Y. [Department of Engineering Physics, Faculty of Engineering, Ankara University, TR-06100 Besevler-Ankara (Turkey); Ehrenberg, H. [Institute for Materials Science, Darmstadt University of Technology, Petersenstrasse 23, D-64287 Darmstadt (Germany); Fuess, H. [Institute for Materials Science, Darmstadt University of Technology, Petersenstrasse 23, D-64287 Darmstadt (Germany); Daoud-Aladine, A. [Laboratory for Neutron Scattering, ETHZ and PSI, CH-5232 Villigen (Switzerland)

    2005-11-10

    The various magnetic structures and phase transitions in the LaMn{sub 2-x}Fe{sub x}Si{sub 2} system have been thoroughly studied by X-ray powder diffraction, magnetic measurements and powder neutron diffraction. The substitution of Fe for Mn leads to a decrease in the lattice parameters and the magnetic interactions in the Mn sublattice crossover from a ferromagnetic character to an antiferromagnetic one. For the x=0.475 sample, a field-induced metamagnetic transition from canted antiferromagnetism to canted ferromagnetism occurs at about 3kOe. The magnetic structures of the LaMn{sub 2-x}Fe{sub x}Si{sub 2} compounds with x=0.2, 0.475, 0.5, 0.7 and 1.0 have been determined between 2 and 450K by neutron diffraction. A typical SmMn{sub 2}Ge{sub 2}-like magnetic behavior is observed for the x=0.475 sample. The magnetic phase transition from ferromagnetism to antiferromagnetism for this sample occurs at the intra-layer Mn-Mn distance d{sub Mn-Mn}{sup a}=2.89A. This value exceeds the well-known corresponding threshold value d{sub Mn-Mn}{sup a}=2.87A in the RMn{sub 2}X{sub 2} compounds. The results are summarized in the LaMn{sub 2-x}Fe{sub x}Si{sub 2} magnetic phase diagram. iagram.

  13. Magnetic separation in microfluidic systems using microfabricated electromagnets - Experiments and simulations

    DEFF Research Database (Denmark)

    Smistrup, Kristian; Hansen, Ole; Bruus, Henrik;

    2005-01-01

    We present experiments and simulations of magnetic separation of magnetic beads in a microfluidic channel. The separation is obtained by microfabricated electromagnets. The results of our simulations using FEMLAB and Mathematica are compared with experimental results obtained using our own microf...... microfabricated systems. (c) 2005 Elsevier B.V. All rights reserved....

  14. Rotation of the solenoid magnet of the CMS experiment before the insertion into its cryostat

    CERN Multimedia

    Patrice Loiez

    2005-01-01

    At one side of the 27 km ring of the future Large Hadron Collider (LHC), the 230 tonne solenoid magnet for the CMS experiment has been rotated through 90° prior to insertion into its cryostat - the jacket that will cool the magnet to 4.2 K (-269° C).

  15. Using Experiment and Computer Modeling to Determine the Off-Axis Magnetic Field of a Solenoid

    Science.gov (United States)

    Lietor-Santos, Juan Jose

    2014-01-01

    The study of the ideal solenoid is a common topic among introductory-based physics textbooks and a typical current arrangement in laboratory hands-on experiences where the magnetic field inside a solenoid is determined at different currents and at different distances from its center using a magnetic probe. It additionally provides a very simple…

  16. A prototype vector magnetic field monitoring system for a neutron electric dipole moment experiment

    CERN Document Server

    Nouri, N; Brown, M A; Carr, R; Filippone, B; Osthelder, C; Plaster, B; Slutsky, S; Swank, C

    2015-01-01

    We present results from a first demonstration of a magnetic field monitoring system for a neutron electric dipole moment experiment. The system is designed to reconstruct the vector components of the magnetic field in the interior measurement region solely from exterior measurements.

  17. New bounds on neutrino electric millicharge from GEMMA experiment on neutrino magnetic moment

    CERN Document Server

    Brudanin, Victor B; Starostin, Alexander S; Studenikin, Alexander I

    2014-01-01

    Using the new limit on the neutrino anomalous magnetic moment recently obtained by GEMMA experiment we get an order-of-magnitude estimation for possible new direct upper bound on the neutrino electric millicharge $\\mid q_{\

  18. Diffractive Physics

    CERN Document Server

    Martin, A D; Khoze, V A; Krauss, F; Ryskin, M G; Zapp, K

    2012-01-01

    `Soft' high-energy interactions are clearly important in pp collisions. Indeed, these events are dominant by many orders of magnitude, and about 40% are of diffractive origin; that is, due to elastic scattering or proton dissociation. Moreover, soft interactions unavoidably give an underlying component to the rare `hard' events, from which we hope to extract new physics. Here, we discuss how to quantify this contamination. First we present a brief introduction to diffraction. We emphasize the different treatment required for proton dissociation into low- and high-mass systems; the former requiring a multichannel eikonal approach, and the latter the computation of triple-Pomeron diagrams with multi-Pomeron corrections. Then we give an overview of the Pomeron, and explain how the QCD (BFKL-type) Pomeron is the natural object to continue from the `hard' to the `soft' domain. In this way we can obtain a partonic description of soft interactions. We introduce the so-called KMR model, based on this partonic approac...

  19. Reference layer exchange in spin transfer torque experiment using magnetic-coated nanometric point contacts

    Science.gov (United States)

    Cunha, R. O.; Baptista, D. L.; Heinemann, M.; Kuhn, M. F.; Schmidt, J. E.; Pereira, L. G.

    2012-09-01

    We investigate the importance of using nanotips on a point contact spin-transfer torque (STT) experiment. A systematic analysis comparing the STT in a magnetic thin film in current-perpendicular-to-plane (CPP) geometry sample for magnetic coated and uncoated tungsten nanotips is shown. The STT effect presents a reverse resistance to current behavior when using a magnetic coating layer on the nanotips. We demonstrate that the magnetic layer on the tip may assume the role of a polarizer layer. This effect opens up the possibility of exploiting simpler architectures in STT-based devices, such as STT-random access memory (STT-RAM).

  20. A Laboratory Plasma Experiment for Studying Magnetic Dynamics of Accretion Discs and Jets

    CERN Document Server

    Hsu, S C

    2002-01-01

    This work describes a laboratory plasma experiment and initial results which should give insight into the magnetic dynamics of accretion discs and jets. A high-speed multiple-frame CCD camera reveals images of the formation and helical instability of a collimated plasma, similar to MHD models of disc jets, and also plasma detachment associated with spheromak formation, which may have relevance to disc winds and flares. The plasmas are produced by a planar magnetized coaxial gun. The resulting magnetic topology is dependent on the details of magnetic helicity injection, namely the force-free state eigenvalue alpha_gun imposed by the coaxial gun.

  1. Magnetic behavior of the giant Heisenberg molecular magnet Mo_72Fe_30: Classical theory and experiment

    Science.gov (United States)

    Luban, Marshall; Modler, Robert; Axenovich, Maria; Canfield, Paul; Bud'Ko, Sergey; Schröder, Christian; Schnack, Jürgen; Müller, Achim; Kögerler, Paul; Harrison, Neil

    2001-03-01

    The Keplerate species Mo_72Fe_30 containing 30 high-spin Fe^3+ ions, is by far the largest paramagnetic molecule synthesized to date, and it serves as an effective building block and prototype for a new class of diverse molybdenum-oxygen based compounds. These substances are of importance for identifying the most pertinent criteria for the passage from microscopic to macroscopic magnetism, and for their potential as molecular-based electronic and magnetic devices. We report excellent agreement, from room temperature down to 0.1 K, and for magnetic fields up to 60 Tesla between our theoretical results based on the classical Heisenberg model and our measurements of its magnetic properties.

  2. submitter The Ultra-Stable Magnet of the Mark II Experiment

    CERN Document Server

    Tommasini, D; Eichenberger, A; Vorotszhov, A

    2016-01-01

    A new watt balance experiment is under development at the Federal Institute of Metrology (METAS, Switzerland). Its scope is to link the mass unit to the Plank constant in order to set a new definition of the kilogram, which is no longer based on the international prototype. The experiment is performed in two steps with the same setup and requires that the magnetic field produced in the two steps by the magnet fitted in the setup remains stable within few parts per $10^8$. This paper describes the design, manufacture, and characterization of this magnet, which is performed through a collaboration between METAS and CERN.

  3. Laboratory experiments on plasma jets in a magnetic field using high-power lasers

    Directory of Open Access Journals (Sweden)

    Nishio K.

    2013-11-01

    Full Text Available The experiments to simulate astrophysical jet generation are performed using Gekko XII (GXII HIPER laser system at the Institute of Laser Engineering. In the experiments a fast plasma flow generated by shooting a CH plane (10 μm thickness is observed at the rear side of the plane. By separating the focal spot of the main beams, a non-uniform plasma is generated. The non-uniform plasma flow in an external magnetic field (0.2∼0.3 T perpendicular to the plasma is more collimated than that without the external magnetic field. The plasma β, the ratio between the plasma and magnetic pressure, is ≫ 1, and the magnetic Reynolds number is ∼150 in the collimated plasma. It is considered that the magnetic field is distorted by the plasma flow and enhances the jet collimation.

  4. Laboratory experiments on plasma jets in a magnetic field using high-power lasers

    Science.gov (United States)

    Nishio, K.; Sakawa, Y.; Kuramitsu, Y.; Morita, T.; Ide, T.; Kuwada, M.; Koga, M.; Kato, T.; Norimatsu, T.; Gregory, C.; Woolsey, N.; Murphy, C.; Gregori, G.; Schaar, K.; Diziere, A.; Koenig, M.; Pelka, A.; Wang, S.; Dong, Q.; Li, Y.; Takabe, H.

    2013-11-01

    The experiments to simulate astrophysical jet generation are performed using Gekko XII (GXII) HIPER laser system at the Institute of Laser Engineering. In the experiments a fast plasma flow generated by shooting a CH plane (10 μm thickness) is observed at the rear side of the plane. By separating the focal spot of the main beams, a non-uniform plasma is generated. The non-uniform plasma flow in an external magnetic field (0.2˜0.3 T) perpendicular to the plasma is more collimated than that without the external magnetic field. The plasma β, the ratio between the plasma and magnetic pressure, is ≫ 1, and the magnetic Reynolds number is ˜150 in the collimated plasma. It is considered that the magnetic field is distorted by the plasma flow and enhances the jet collimation.

  5. Loading experiment and thermal analysis for conduction cooled magnet of SMES system

    Institute of Scientific and Technical Information of China (English)

    Gang WU; Huiling WANG; Jiangbo XIE; Yan ZHAO; Yuejin TANG; Jindong LI; Jing SHI

    2009-01-01

    China's first 35kJ high temperature superconducting magnetic energy storage (SMES) system with an experiment equipment was depicted. The dynamic heat analysis of the magnet of the SMES was conducted through the current load test on the directly cooled conduction magnet. The research results were as follows:when the converter charges and discharges the magnet for energy storage, the hysteresis loss is the main part of power loss, and contributes significantly to temperature rise;reducing the current frequency at the side of direct current is conducive to restraining temperature rise. The optimizing factors of the cool-guide structure were analyzed based on the heat stability theory, and it was found that the heat transfer of its key part (at the top of the magnet) must be strengthened to reduce the axial temperature difference of the magnet.

  6. Measurement and tricubic interpolation of the magnetic field for the OLYMPUS experiment

    CERN Document Server

    Bernauer, J C; Elbakian, G; Gavrilov, G; Goerrissen, N; Hasel, D K; Henderson, B S; Holler, Y; Karyan, G; Ludwig, J; Marukyan, H; Naryshkin, Y; O'Connor, C; Russell, R L; Schmidt, A; Schneekloth, U; Suvorov, K; Veretennikov, D

    2016-01-01

    The OLYMPUS experiment used a 0.3 T toroidal magnetic spectrometer to measure the momenta of outgoing charged particles. In order to accurately determine particle trajectories, knowledge of the magnetic field was needed throughout the spectrometer volume. For that purpose, the magnetic field was measured at over 36,000 positions using a three-dimensional Hall probe actuated by a system of translation tables. We used these field data to fit a numerical magnetic field model, which could be employed to calculate the magnetic field at any point in the spectrometer volume. Calculations with this model were computationally intensive; for analysis applications where speed was crucial, we pre-computed the magnetic field and its derivatives on an evenly spaced grid so that the field could be interpolated between grid points. We developed a spline-based interpolation scheme suitable for SIMD implementations, with a memory layout chosen to minimize space and optimize the cache behavior to quickly calculate field values....

  7. Thermal structural characterization of the acentric layered perovskite LiHSrTa2O7: X-ray and neutron diffraction, SHG and Raman experiments.

    Science.gov (United States)

    Galven, Cyrille; Mounier, Denis; Pagnier, Thierry; Suard, Emmanuelle; Le Berre, Françoise; Crosnier-Lopez, Marie-Pierre

    2014-10-21

    The present work concerns the thermal structural characterization of the acentric Ruddlesden-Popper LiHSrTa2O7. A previous study, performed with powder neutron diffraction data, has revealed that at room temperature, LiHSrTa2O7 crystallizes in the Ama2 space group and that the acentric character is mainly due to the unequal distribution of the Li(+) and H(+) cations on their sites. In this new paper, the thermal behaviour has been studied by several techniques: powder X-ray and neutron diffraction, SHG experiments and Raman spectroscopy. All of them have revealed that LiHSrTa2O7 undergoes a reversible structural transition from an orthorhombic to a tetragonal symmetry around 200 °C. This transition is associated with the progressive vanishing of the TaO6 octahedra tilting, becoming completely straight in the high temperature form (S.G. I4/mmm), and with a variation of the Li(+) and H(+) distribution in the interlayer spacing.

  8. Cooperative photo-induced effects: from photo-magnetism under continuous irradiation to ultra-fast phenomena - study through optical spectroscopy and X-ray diffraction; Effets photo-induits cooperatifs: du photomagnetisme sous irradiation continue aux phenomenes ultrarapides - etude par spectroscopie optique et diffraction X

    Energy Technology Data Exchange (ETDEWEB)

    Glijer, D

    2006-12-15

    The control with ultra-short laser pulses of the collective and concerted transformation of molecules driving a macroscopic state switching on an ultra-fast time scale in solid state opens new prospects in materials science. The goal is to realize at the material level what happens at the molecular level in femto-chemistry. These processes are highly cooperative and highly non-linear, leading to self-amplification and self-organization within the material, a so-called photo-induced phase transition with a new long range order (structural, magnetic, ferroelectric,...). Two families of molecular compounds have been studied here: first of all, spin transition materials changing from a diamagnetic state over to a paramagnetic state under the effect of temperature or under continuous laser excitation. It concerns photo-active molecular bi-stability prototype materials in solid state, whose switching has been studied during X-ray diffraction, optical reflectivity and magnetism experiments. Then we have studied charge-transfer molecular systems, prototype compounds for ultrafast photo-induced phase transitions: insulator-metal, neutral-ionic....As well as ultrafast optical experiments, time-resolved X ray crystallography is a key technique in order to follow at the atomic level the different steps of the photo-induced transformation and thus to observe the involved mechanisms. We have underlined a process of photo-formation of one-dimensional nano-domains of lattice-relaxed charge-transfer excitations, governing the photo-induced phase transition of the molecular charge-transfer complex TTF-CA by the first time-resolved diffuse scattering measurements. Moreover, a new femtosecond laser-plasma source and a optical pump-probe spectroscopy set-up with a highly sensitive detecting system have been developed in this work. The results presented here will be an illustration of the present scientific challenges existing on the one hand with the development of projects of major

  9. Engagement in RNs working in Magnet®-designated hospitals: exploring the significance of work experience.

    Science.gov (United States)

    Hagedorn Wonder, Amy

    2012-12-01

    This study analyzed and evaluated the relationships between work engagement (WE) and work experience among acute-care RNs in Magnet®-designated hospitals. The organizational structures of Magnet-designated hospitals are recognized to promote RN engagement, yet limited knowledge exists on engendering engagement to the same degree in all nurses. The study used a descriptive, correlational design. A convenience sample of RNs (n = 220) completed 2 surveys to measure WE, RN experience, and unit longevity (years of experience in the current setting). Significant relationships were found between WE and RN experience in any setting, within the consistent organizational structures of Magnet-designated hospitals. This study highlights the importance of organizational structures and the significance of RN experience in creating engagement among nurses. Enhancing engagement in the RN workforce facilitates retention and improved outcomes for patients, nurses, and organizations.

  10. X-ray diffraction observations of a charge-density-wave order in superconducting ortho-II YBa2Cu3O6.54 single crystals in zero magnetic field

    DEFF Research Database (Denmark)

    Blackburn, E.; Chang, J.; Hücker, M.;

    2013-01-01

    X-ray diffraction measurements show that the high-temperature superconductor YBa2Cu3O6.54, with ortho-II oxygen order, has charge-density-wave order in the absence of an applied magnetic field. The dominant wave vector of the charge density wave is qCDW=(0,0.328(2),0.5), with the in-plane compone...

  11. Mapping the omega-effect in the DTS magnetized spherical Couette flow experiment

    CERN Document Server

    Nataf, Henri-Claude

    2012-01-01

    The DTS experiment is a spherical Couette flow experiment with an imposed dipolar magnetic field. Liquid sodium is used as a working fluid. In a series of measurement campaigns, we have obtained data on the mean axisymmetric velocity, the mean induced magnetic field and electric potentials. All these quantities are coupled through the induction equation. In particular, a strong omega-effect is produced by differential rotation within the fluid shell, inducing a significant azimuthal magnetic field. Taking advantage of the simple spherical geometry of the experiment, I expand the azimuthal and meridional fields into Legendre polynomials and derive the expressions that permit to relate all measurements to the radial functions of the velocity field for each harmonic degree. For small magnetic Reynolds numbers Rm the relations are linear, and the toroidal and poloidal equations decouple. Selecting a set of measurements for a given rotation frequency of the inner sphere (Rm = 9.4), I invert simultaneously the velo...

  12. "School Adopts an Experiment": The Magnetic Levitation of Superconductors

    Science.gov (United States)

    Gallitto, Aurelio Agliolo

    2010-01-01

    The event "School adopts an experiment" is an event targeted at high schools and secondary schools. It is based on a tight and direct collaboration between researchers and school students and teachers. Several schools were involved in the event by "adopting" an experiment in physics research laboratories. Groups of selected students were first…

  13. "School Adopts an Experiment": The Magnetic Levitation of Superconductors

    Science.gov (United States)

    Gallitto, Aurelio Agliolo

    2010-01-01

    The event "School adopts an experiment" is an event targeted at high schools and secondary schools. It is based on a tight and direct collaboration between researchers and school students and teachers. Several schools were involved in the event by "adopting" an experiment in physics research laboratories. Groups of selected students were first…

  14. 'School adopts an experiment': the magnetic levitation of superconductors

    Science.gov (United States)

    Agliolo Gallitto, Aurelio

    2010-09-01

    The event 'School adopts an experiment' is an event targeted at high schools and secondary schools. It is based on a tight and direct collaboration between researchers and school students and teachers. Several schools were involved in the event by 'adopting' an experiment in physics research laboratories. Groups of selected students were first trained by university researchers, then they demonstrated the experiments to other students and teachers during the event. Students who adopted an experiment acquired knowledge of the subjects connected with the experiment in a most impressive way compared with the usual didactics at school. Further positive points were: (i) to establish a close and direct collaboration between university researchers and high-school students and teachers; (ii) to give school students the opportunity to visit physics research laboratories.

  15. Isotopic quantum effects in the structure of liquid methanol: I. Experiments with high-energy photon diffraction

    Science.gov (United States)

    Tomberli, B.; Egelstaff, P. A.; Benmore, C. J.; Neuefeind, J.

    2001-12-01

    High-energy electromagnetic radiation scattering techniques have been used to measure the structural differences between four isotopic samples of methanol (CH3OH, CD3OD, CH3OD and CD3OH). The first series of experiments employed room temperature and ambient pressure. The carbon-oxygen intramolecular bond length was measured and found to depend more strongly on the isotopic substitution at the hydroxyl site than at the methyl sites. The oscillations in the isotopic difference of the x-ray structure factor, ΔSX(Q), are shown at room temperature to be about 2% as large as the oscillations in the total structure factor. Our uncertainties are an order of magnitude smaller than those of previous gamma ray measurements (Benmore C J and Egelstaff P A 1996 J. Phys.: Condens. Matter 8 9429-32). A second series of experiments was carried out at -80 °C at its vapour pressure in order to study the significant temperature dependence of these effects. The ΔSX(Q) difference at -80 °C is shown to be up to three times larger than the room temperature difference. These studies showed that isotopic structural differences in methanol may be represented as temperature shifts that vary as a function of thermodynamic state and substitution site.

  16. Diffractive and Exclusive Processes at CMS

    CERN Document Server

    Kuznetsova, Ekaterina

    2014-01-01

    We present an overview of the CMS results on diffractive and exclusive production.Measurements of inclusive single and double diffractive production are discussedas well as measurements of the diffractive production at a hard scale. Measurementsof charged particle multiplicities for single diffractive enhanced data sample and studies of central diffractive jet production were perfrmed in a collaboration with the TOTEM experiment. CMS results on cross section measurements for exclusive dilepton and WW production are also presented.

  17. QtUCP-A program for determining unit-cell parameters in electron diffraction experiments using double-tilt and rotation-tilt holders

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Hongsheng [Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011 (China); Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China)], E-mail: zhaohscas@yahoo.com.cn; Wu Deqi [Xinjiang Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Urumqi 830011 (China); Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Yao Jincheng; Chang Aimin [Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China)

    2008-11-15

    A computer program, QtUCP, has been developed based on several well-established algorithms using GCC 4.0 and Qt 4.0 (Open Source Edition) under Debian GNU/Linux 4.0r0. It can determine the unit-cell parameters from an electron diffraction tilt series obtained from both double-tilt and rotation-tilt holders. In this approach, two or more primitive cells of the reciprocal lattice are determined from experimental data, in the meantime, the measurement errors of the tilt angles are checked and minimized. Subsequently, the derived primitive cells are converted into the reduced form and then transformed into the reduced direct primitive cell. Finally all the patterns are indexed and the least-squares refinement is employed to obtain the optimized results of the lattice parameters. Finally, two examples are given to show the application of the program, one is based on the experiment, the other is from the simulation.

  18. QtUCP-a program for determining unit-cell parameters in electron diffraction experiments using double-tilt and rotation-tilt holders.

    Science.gov (United States)

    Zhao, Hongsheng; Wu, Deqi; Yao, Jincheng; Chang, Aimin

    2008-11-01

    A computer program, QtUCP, has been developed based on several well-established algorithms using GCC 4.0 and Qt 4.0 (Open Source Edition) under Debian GNU/Linux 4.0r0. It can determine the unit-cell parameters from an electron diffraction tilt series obtained from both double-tilt and rotation-tilt holders. In this approach, two or more primitive cells of the reciprocal lattice are determined from experimental data, in the meantime, the measurement errors of the tilt angles are checked and minimized. Subsequently, the derived primitive cells are converted into the reduced form and then transformed into the reduced direct primitive cell. Finally all the patterns are indexed and the least-squares refinement is employed to obtain the optimized results of the lattice parameters. Finally, two examples are given to show the application of the program, one is based on the experiment, the other is from the simulation.

  19. SU-E-J-233: A Facility for Radiobiological Experiments in a Large Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Carlone, M; Heaton, R; Keller, H [Princess Margaret Hospital, Toronto, ON (Canada); University of Toronto, Toronto, ON (Canada); Wouters, B [Ontario Cancer Institute, Toronto, ON (Canada); University of Toronto, Toronto, ON (Canada); Jaffray, D [Princess Margaret Hospital, Toronto, ON (Canada); Ontario Cancer Institute, Toronto, ON (Canada); University of Toronto, Toronto, ON (Canada)

    2014-06-01

    Purpose: There is considerable interest in developing medical linear accelerators with integrated image guidance by MRI. Less work has been done on the fundamental biology of cell survival in the presence of a strong magnetic field. The purpose of this work is to describe an experimental system capable of measuring cell survival response in the types of MRI-linac systems currently under development. Methods: We have integrated a cobalt irradiator with a solenoid magnet. The solenoid magnet has inner diameter of 10 cm. To enable measurement of the biological effects as a function of depth, we are utilizing the sliced gel technique, in which cells are embedded and fixed within a gelatin matrix. Irradiated cells at defined positions (sub mm resolution) can subsequently be recovered and assessed for cell survival or other biological effects. Results: The magnetic field profile in the solenoid has a peak magnetic field 36 cm below the top edge of the magnet bore and can be placed at and SAD of 100 cm. At a solenoid current of 35 A, the peak magnetic field is 0.25 T. The dose rate of the cobalt irradiator is 16 cGy/min at 100 cm SAD. EBT3 film was used to demonstrate the system functionality. It was irradiated at 1 cm depth at 100 cm SSD with a 4×4 field to 1.5 Gy in a 0.25 T magnetic field. The dose profile was similar between this film and the control exposure without magnetic field. Conclusion: Integrating a cobalt irradiator with a high field magnet is demonstrated. The magnetic field at the cobalt defining head was minimal and did not interfere with the functioning of this unit. Cell survival experiments can be reproduced exactly in the presence or absence of a magnetic field since a resistive magnet is used.

  20. Threshold photoemission magnetic circular dichroism of perpendicularly magnetized Ni films on Cu(001): theory and experiment

    Energy Technology Data Exchange (ETDEWEB)

    Kronseder, Matthias; Guenther, Stefan; Woltersdorf, Georg; Back, Christian H. [Universitaet Regensburg, Regensburg (Germany)

    2011-07-01

    Threshold photoemission magnetic circular dichroism (TP-MCD) for perpendicularly magnetized Ni films on Cu(001) was measured with a total electron yield method. This dichroism was used to observe the magnetic domain structure of these samples in a photoemission electron microscope. A spin-polarized relativistic Korringa-Kohn-Rostoker Green's function calculation including a dynamical mean field theory approach within the one-step-photoemission model reproduces the measured asymmetry in the photocurrents for left and right circularly polarized light. In addition, a three-step photoemission model calculation based on the same ab-initio calculation is used to quantitatively explain the MCD effect near the photoemission threshold. Furthermore, the dependence of the MCD-asymmetry on the polarization state of the incoming photons is theoretically computed and experimentally verified.

  1. Site occupancy and magnetic moment of Fe in Ni{sub 2}Mn{sub 0.3}Fe{sub 0.7}Ga alloy by neutron powder diffraction study

    Energy Technology Data Exchange (ETDEWEB)

    Umetsu, R.Y., E-mail: rieume@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Japan Science and Technology Agency-Precursory Research for Embryonic Science and Technology (JST-PREST), Tokyo 102-0076 (Japan); Kikuchi, D. [Faculty of Engineering, Tohoku Gakuin. University, Tagajo 985-8537 (Japan); Koyama, K. [Faculty of Science, Kagoshima University, Kagoshima 890-0065 (Japan); Watanabe, K.; Yamaguchi, Y. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Kainuma, R. [Department of Material Science, Graduate School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Kanomata, T. [Department of Material Science, Graduate School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Research Institute for Engineering and Technology, Tohoku Gakuin University, Tagajo 985-8537 (Japan)

    2013-12-15

    Highlights: •Neutron powder diffraction measurements were carried out for Ni{sub 2}Mn{sub 0.3}Fe{sub 0.7}Ga shape memory alloy system. •It was clarified that the Mn and Fe atoms randomly occupied at 4a site in the L2{sub 1}-type structure. •Magnetic moment of Fe was estimated to be about 3.0 μ{sub B}, being significantly larger than that in pure bcc-Fe. -- Abstract: Neutron powder diffraction measurements were carried out in a wide temperature range from 14 to 500 K for Ni{sub 2}Mn{sub 0.3}Fe{sub 0.7}Ga alloy, which undergoes a martensitic transformation from L2{sub 1}-type austenite phase to four layered orthorhombic-type martensite phase at about 160 K during cooling. For the diffraction pattern measured at 500 K in the paramagnetic austenite phase, it was clarified that the Mn and Fe atoms randomly occupied 4a site in the L2{sub 1}-type structure. Magnetic moments of Ni, Mn and Fe in the ferromagnetic austenite phase at 200 K were decided to be 0.3 and 3.3 and 3.0 μ{sub B}, respectively. The magnetic moment of Fe is significantly larger than that in pure bcc-Fe of 2.2 μ{sub B}. Magnetic moments of Fe in two sites at 14 K in the martensite phase were obtained to be 2.3 and 2.6 μ{sub B}, respectively, suggesting that the comparatively large magnetic moments of Fe were kept even in the martensite phase. Total magnetic moment of the martensite phase at 14 K from the neutron powder diffractive analyses is 3.7 μ{sub B}/f.u., being in good agreement with the result of the magnetic measurement of 3.5 μ{sub B}/f.u. at 4.2 K.

  2. Magnetic field reversals: the geodynamo, laboratory experiments and models (Lewis Fry Richardson Medal Lecture)

    Science.gov (United States)

    Fauve, S.

    2009-04-01

    I will first compare reversals of Earth's magnetic field known from palaeomagnetic data to the ones observed in a laboratory experiment for the magnetic field generated by a turbulent flow of liquid sodium (VKS experiment). Despite major differences between the flow in Earth's core and in the experiment, both systems display reversals that share a lot of similar properties. I will understand them using a simple model in the framework of low dynamical system theory. Finally, I will discuss what can be learnt from numerical simulations.

  3. Repulsive magnetic levitation-based ocean wave energy harvester with variable resonance: Modeling, simulation and experiment

    Science.gov (United States)

    Masoumi, Masoud; Wang, Ya

    2016-10-01

    This paper investigates a magnetic levitation characteristic used in a vibration based energy harvester, called repulsive magnetic scavenger (RMS). The RMS is capable of harvesting ocean wave energy with a unique repelling permanent magnet array, which provides a stronger and more uniform magnetic field, compared to its attracting magnetic counterparts. The levitating magnets are stacked together around a threaded rod so that the same pole is facing each other. Two fixed magnets placed with one at each end of the RMS provides a collocated harvesting and braking mechanism in the face of high amplitude vibrations. Magnets in the levitated magnet stack are separated by pole pieces which are made of metals to intensify the magnetic field strength. The effect of the thickness and the use of different materials with different permeability for pole pieces is also studied to obtain an optimal energy harvesting efficiency. Moreover, the procedure to find the restoring force applied to the levitating magnet stack is demonstrated. Then, the Duffing vibration equation of the harvester is solved and the frequency response function is calculated for various force amplitudes and electrical damping so as to investigate the effect of these parameters on the response of the system. Furthermore, the effect of the maximum displacement of the moving magnet stack on the natural frequency of the device is studied. And finally, Faraday's law is employed to estimate the output voltage and power of the system under the specified input excitation force. Experiments show that the output emf voltage of the manufactured prototype reaches up to 42 V for an excitation force with the frequency of 9 Hz and the maximum amplitude of 3.4 g.

  4. Experiments on the margin of beam induced quenches a superconducting quadrupole magnet in the LHC

    CERN Document Server

    Bracco, C; Bednarek, M J; Nebot Del Busto, E; Goddard, B; Holzer, E B; Nordt, A; Sapinski, M; Schmidt, R; Solfaroli Camillocci, M; Zerlauth, M

    2012-01-01

    Protection of LHC equipment relies on a complex system of collimators to capture injected and circulating beam in case of LHC kicker magnet failures. However, for specific failures of the injection kickers, the beam can graze the injection protection collimators and induce quenches of downstream superconducting magnets. This occurred twice during 2011 operation and cannot be excluded during future operation. Tests were performed during Machine Development periods of the LHC to assess the quench margin of the quadrupole located just downstream of the last injection protection collimator in point 8. In addition to the existing Quench Protection System, a special monitoring instrumentation was installed at this magnet to detect any resistance increase below the quench limit. The correlation between the magnet and Beam Loss Monitor signals was analysed for different beam intensities and magnet currents. The results of the experiments are presented.

  5. Impact of impellers on the axisymmetric magnetic mode in the VKS2 dynamo experiment.

    Science.gov (United States)

    Laguerre, R; Nore, C; Ribeiro, A; Léorat, J; Guermond, J-L; Plunian, F

    2008-09-05

    In the von Kármán Sodium 2 (VKS2) successful dynamo experiment of September 2006, the observed magnetic field showed a strong axisymmetric component, implying that nonaxisymmetric components of the flow field were acting. By modeling the induction effect of the spiraling flow between the blades of the impellers in a kinematic dynamo code, we find that the axisymmetric magnetic mode is excited. The control parameters are the magnetic Reynolds number of the mean flow, the coefficient measuring the induction effect alpha, and the type of boundary conditions. We show that using realistic values of alpha, the observed critical magnetic Reynolds number, Rm;{c} approximately 32, can be reached easily with ferromagnetic boundary conditions. We conjecture that the dynamo action achieved in this experiment may not be related to the turbulence in the bulk of the flow, but rather to the alpha effect induced by the impellers.

  6. MAGNET

    CERN Multimedia

    Benoit Curé

    2010-01-01

    The magnet was successfully operated at the end of the year 2009 despite some technical problems on the cryogenics. The magnet was ramped up to 3.8 T at the end of November until December 16th when the shutdown started. The magnet operation met a few unexpected stops. The field was reduced to 3.5 T for about 5 hours on December 3rd due to a faulty pressure sensor on the helium compressor. The following day the CERN CCC stopped unintentionally the power converters of the LHC and the experiments, triggering a ramp down that was stopped at 2.7 T. The magnet was back at 3.8 T about 6 hours after CCC sent the CERN-wide command. Three days later, a slow dump was triggered due to a stop of the pump feeding the power converter water-cooling circuit, during an intervention on the water-cooling plant done after several disturbances on the electrical distribution network. The magnet was back at 3.8 T in the evening the same day. On December 10th a break occurred in one turbine of the cold box producing the liquid ...

  7. New limits on Magnetic Monopoles searches from accelerator and non-accelerator experiments

    CERN Document Server

    Cozzi, M

    2007-01-01

    Here the status of the searches for ``classical Dirac'' Magnetic Monopoles (MMs) at accelerators and for GUT MMs in the cosmic radiation is discussed. We present recent analysis for ``classical Dirac'' monopoles at accelerators and the lowest flux upper limit for Magnetic Monopoles in the mass range 10$^{5}$ - 10$^{12}$ GeV obtained with the SLIM experiment at the Chacaltaya High Altitude Laboratory (5290 m a.s.l.).

  8. Gravitational Hertz experiment with electromagnetic radiation in a strong magnetic field

    CERN Document Server

    Kolosnitsyn, N I

    2015-01-01

    Brief review of principal ideas in respect of the high frequency gravitational radiation generated and detected in the laboratory condition is presented. Interaction of electro-magnetic and gravitational waves into a strong magnetic field is considered as a more promising variant of the laboratory GW-Hertz experiment. The formulae of the direct and inverse Gertsenshtein-Zeldovich effect are derived. Numerical estimates are given and a discussion of a possibility of observation of these effects in a lab is carried out.

  9. A Laboratory Plasma Experiment for Studying Magnetic Dynamics of Accretion Discs and Jets

    OpenAIRE

    Hsu, S. C.; Bellan, P. M.

    2002-01-01

    This work describes a laboratory plasma experiment and initial results which should give insight into the magnetic dynamics of accretion discs and jets. A high-speed multiple-frame CCD camera reveals images of the formation and helical instability of a collimated plasma, similar to MHD models of disc jets, and also plasma detachment associated with spheromak formation, which may have relevance to disc winds and flares. The plasmas are produced by a planar magnetized coaxial gun. The resulting...

  10. Novel Pr-Cu Magnetic Phase at Low Temperature in PrBa{sub 2}Cu{sub 3}O{sub 6{ital +x}} Observed by Neutron Diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Boothroyd, A.; Longmore, A. [Clarendon Laboratory, Oxford University, Oxford, OX1 3PU (United Kingdom); Andersen, N. [Department of Solid State Physics, Riso/ National Laboratory, DK-4000 Roskilde (Denmark); Brecht, E. [Forschungszentrum Karlsruhe, INFP, D-76021 Karlsruhe (Germany); Wolf, T. [Forschungszentrum Karlsruhe, ITP, D-76021 Karlsruhe (Germany)

    1997-01-01

    We have studied by neutron diffraction the magnetic ordering in Al-free crystals of PrBa{sub 2}Cu{sub 3}O{sub 6+x} (x=0.35 and 0.92) that do not display the AFII Cu magnetic phase. We find that the Pr ordering below 20K is accompanied by a counterrotation of the Cu antiferromagnetism on each plane of the bilayer. The maximum turn angle between the two planes is 60{degree}{plus_minus}9{degree} for the x=0.92 crystal, and 40{degree}{plus_minus}11{degree} for the x=0.35 crystal. This is the first observation of a noncollinear ordering of Cu moments in the bilayer, and is evidence for significant magnetic coupling between the Cu and Pr sublattices. {copyright} {ital 1996} {ital The American Physical Society}

  11. Neutron-diffraction measurements of magnetic order and a structural transition in the parent BaFe2As2 compound of FeAs-based high-temperature superconductors.

    Science.gov (United States)

    Huang, Q; Qiu, Y; Bao, Wei; Green, M A; Lynn, J W; Gasparovic, Y C; Wu, T; Wu, G; Chen, X H

    2008-12-19

    The recent discovery of superconductivity in (Ba,K)Fe2As2, which crystallizes in the ThCr2Si2 (122) structure as compared with the LnFeAsO (Ln is lanthanide) systems that possess the ZrCuSiAs (1111) structure, demonstrates the exciting potential of the FeAs-based materials for high-T{C} superconductivity. Here we report neutron diffraction studies that show a tetragonal-to-orthorhombic distortion associated with the onset of q=(101) antiferromagnetic order in BaFe2As2, with a saturation moment 0.87(3)micro {B} per Fe that is orientated along the longer a axis of the ab planes. The simultaneous first-order structural and magnetic transition is in contrast with the separated transitions previously reported in the 1111-type materials. The orientational relation between magnetic alignment and lattice distortion supports a multiorbital nature for the magnetic order.

  12. X-ray Absorption Spectroscopy and Coherent X-ray Diffraction Imaging for Time-Resolved Investigation of the Biological Complexes: Computer Modelling towards the XFEL Experiment

    Science.gov (United States)

    Bugaev, A. L.; Guda, A. A.; Yefanov, O. M.; Lorenz, U.; Soldatov, A. V.; Vartanyants, I. A.

    2016-05-01

    The development of the next generation synchrotron radiation sources - free electron lasers - is approaching to become an effective tool for the time-resolved experiments aimed to solve actual problems in various fields such as chemistry’ biology’ medicine’ etc. In order to demonstrate’ how these experiments may be performed for the real systems to obtain information at the atomic and macromolecular levels’ we have performed a molecular dynamics computer simulation combined with quantum chemistry calculations for the human phosphoglycerate kinase enzyme with Mg containing substrate. The simulated structures were used to calculate coherent X-ray diffraction patterns’ reflecting the conformational state of the enzyme, and Mg K-edge X-ray absorption spectra, which depend on the local structure of the substrate. These two techniques give complementary information making such an approach highly effective for time-resolved investigation of various biological complexes, such as metalloproteins or enzymes with metal-containing substrate, to obtain information about both metal-containing active site or substrate and the atomic structure of each conformation.

  13. Magnetic modulation vectors in Nd rich Nd-Pr alloys

    DEFF Research Database (Denmark)

    Wolny, J.; Lebech, B.

    1995-01-01

    The temperature dependencies of the magnetic modulation vectors for two single crystals of Nd0.75Pr0.25 and Nd0.65Pr0.35 have been determined from neutron diffraction experiments.......The temperature dependencies of the magnetic modulation vectors for two single crystals of Nd0.75Pr0.25 and Nd0.65Pr0.35 have been determined from neutron diffraction experiments....

  14. A magnetic pulse does not affect homing pigeon navigation: a GPS tracking experiment.

    Science.gov (United States)

    Holland, Richard; Filannino, Caterina; Gagliardo, Anna

    2013-06-15

    The cues by which homing pigeons are able to return to a home loft after displacement to unfamiliar release sites remain debated. A number of experiments in which migratory birds have been treated with a magnetic pulse have produced a disruption in their orientation, which argues that a ferrimagnetic sense is used for navigation in birds. One previous experiment has also indicated an effect of magnetic pulses on homing pigeon navigation, although with inconsistent results. Previous studies have shown that some magnetic-related information is transmitted by the trigeminal nerve to the brain in some bird species, including the homing pigeon. The function of this information is still unclear. It has been suggested that this information is important for navigation. Previous studies with trigeminal nerve lesioned homing pigeons have clearly shown that the lack of trigeminally mediated information, even if magnetic, is not crucial for homing performance. However, this result does not completely exclude the possibility that other ferrimagnetic receptors in the homing pigeon play a role in navigation. Additionally, recent studies on homing pigeons suggested the existence of a ferrimagnetic sense in a novel location presumably located in the inner ear (lagena). In the present study, we tested whether any ferrimagnetic magnetoreceptors, irrespective of their location in the bird's head, are involved in pigeons' homing. To do this, we treated homing pigeons with a strong magnetic pulse before release, tracked birds with GPS loggers and analyzed whether this treatment affected homing performance. In the single previous magnetic pulse experiment on homing pigeons, only initial orientation at a release site was considered and the results were inconsistent. We observed no effect of the magnetic pulse at any of the sites used on initial orientation, homing performance, tortuosity or track efficiency, which does not support a role for the ferrimagnetic sense in homing pigeon

  15. Synchrotron Applications of High Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    This workshop aims at discussing the scientific potential of X-ray diffraction and spectroscopy in magnetic fields above 30 T. Pulsed magnetic fields in the range of 30 to 40 T have recently become available at Spring-8 and the ESRF (European synchrotron radiation facility). This document gathers the transparencies of the 6 following presentations: 1) pulsed magnetic fields at ESRF: first results; 2) X-ray spectroscopy and diffraction experiments by using mini-coils: applications to valence state transition and frustrated magnet; 3) R{sub 5}(Si{sub x}Ge{sub 1-x}){sub 4}: an ideal system to be studied in X-ray under high magnetic field?; 4) high field studies at the Advanced Photon Source: present status and future plans; 5) synchrotron X-ray diffraction studies under extreme conditions; and 6) projects for pulsed and steady high magnetic fields at the ESRF.

  16. Experience with a Pre-Series Superfluid Helium Test Bench for LHC Magnets

    CERN Document Server

    Benda, V; Schouten, J A

    2000-01-01

    The Large Hadron Collider (LHC) under construction at CERN is based on the use of high-field superconducting magnets operating in superfluid helium. For the validation of the machine dipoles and quadrupoles, a magnet test plant is under construction requiring 12 so-called Cryogenic Feeder Units (CFU). Based on experience done at CERN, two pre-series CFUs were designed and built by industry and are currently in use prior to final series delivery. This presentation describes the features of a CFU, its typical characteristics and the experience acquired with the first units.

  17. Exploration of Experiment on Measuring Magnetic Permeability of Soft Magnetic Materials%软磁材料磁导率测量实验探索

    Institute of Scientific and Technical Information of China (English)

    董向成; 吴学勇

    2016-01-01

    软磁材料磁滞回线细长,计算精度不高时忽略其磁滞,可定义磁感应强度与磁场强度的比为磁导率。利用霍尔效应实验仪对螺线管加载软磁材料前后一端的磁感应强度进行测量,计算出该端点处的磁场强度即可计算出该种软磁材料的磁导率,实验表明在材料磁饱和后,磁导率迅速降低。%Since the hysteresis loop of the soft magnetic material is thin,in the case of calculation accuracy is not high that the magnetic hysteresis can be neglected,so magnetic permeability can be defined as the ratio of magnetic induction and magnetic field strength.under the condition with and without the iron core,magnetic in-duction intensity can be measured at one end of the solenoid by Hall effect experiment instrument,calculate magnetic field intensity on the axis of the solenoid,then the magnetic permeability of the soft magnetic matrial can be calculated based on the magnetic intensity.Afer the materia reach the magnetic saturation,experiments show that the magnetic permeability is rapidly decreased.

  18. Pressure-induced instability of magnetic order in Kondo-lattice system. Neutron diffraction study of the pseudo-binary alloy system Ce(Ru sub 0 sub . sub 9 sub 0 Rh sub 0 sub . sub 1 sub 0) sub 2 (Si sub 1 sub - sub y Ge sub y) sub 2

    CERN Document Server

    Watanabe, K; Kanadani, C; Taniguchi, T; Kawarazaki, S; Uwatoko, Y; Kadowaki, H

    2003-01-01

    Neutron diffraction experiments have been carried out to study the nature of the magnetic order of the pseudo-binary alloy system Ce(Ru sub 0 sub . sub 9 sub 0 Rh sub 0 sub . sub 1 sub 0) sub 2 (Si sub 1 sub - sub y Ge sub y) sub 2. Response of the ordered atomic magnetic moment, mu, the transition temperature, T sub N , and the magnitude of the magnetic modulation vector, q, to the chemical pressure and also to the applied hydrostatic pressure, P, were examined at low temperatures. When y changes, all of mu, T sub N and q show a sudden alteration of the manner of the y-dependence at around y - 0.08. The P-dependence of q shows quite different features for different y's of 0.0, 0.2 and 0.25. On the basis of these observations the possibility of a pressure-induced alternation of the magnetic regime of the order is discussed. (author)

  19. Neutron diffraction study of the magnetic ordering of the Cu sup ++ spins in Nd sub 1. 5 Ba sub 1. 5 Cu sub 3 O sub 6+x

    Energy Technology Data Exchange (ETDEWEB)

    Moudden, A.H.; Hennion, B. (Lab. Leon Brillouin, CEA-CNRS, CEN/Saclay, 91 - Gif-sur-Yvette (France)); Schweiss, P. (Lab. Leon Brillouin, CEA-CNRS, CEN/Saclay, 91 - Gif-sur-Yvette (France) Kernforschungszentrum Karlsruhe, INFP (Germany)); Gehring, P.M.; Shirane, G. (Brookhaven National Lab., Upton, NY (United States)); Hidaka, Y. (NTT Applied Electronics Labs., Ibaraki (Japan))

    1991-12-01

    Elastic neutron scattering experiments performed on single crystals of Nd{sub 1.5}Ba{sub 1.5}Cu{sub 3}O{sub 6+y} reveal successive antiferromagnetic (AF) ordering of the Cu{sup ++} spins. The as grown single crystals show an AF structure characterized by a Neel temperature T{sub N1}{proportional to}390K and a magnetic wave vector (1/2 1/2 0) referring to the tetragonal structure of NdBa{sub 2}Cu{sub 3}O{sub 6}. As the temperature is lowered below T{sub N2}{proportional to}150 K, a spin reorientation develops and a second AF ordering with (1/2 1/2 1/2) wave vector is stabilized. When the samples are oxygenated the tetragonal symmetry and the Neel temperature T{sub N1} remain unchanged, whereas the spin reorientation at T{sub N2} is suppressed. The results indicate that the Nd/Ba substitution increases the stability of the tetragonal structure upon the oxygen content. This may induce new possibilities of local oxygen ordering that favour the presence of holes in the deficient layer. (orig.).

  20. Cation distribution in Ba{sub 2}(Fe,W{sub 0.5}Mo{sub 0.5}){sub 2}O{sub 6} double-perovskites: A combined synchrotron and neutron diffraction, magnetization and Moessbauer spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Rammeh, N. [Laboratoire de Physique des Materiaux, Faculte des Sciences de Sfax, BP 1171, 3000 Sfax (Tunisia); Institute for Materials Science, University of Technology, D-64287 Darmstadt (Germany); Ehrenberg, H. [Institute for Materials Science, University of Technology, D-64287 Darmstadt (Germany); Ritter, C. [Institut Laue Langevin, BP 156, F-38042 Grenoble Cedex 9 (France); Fuess, H. [Institute for Materials Science, University of Technology, D-64287 Darmstadt (Germany); Cheikhrouhou, A. [Laboratoire de Physique des Materiaux, Faculte des Sciences de Sfax, BP 1171, 3000 Sfax (Tunisia)], E-mail: abdcheikhrouhou@yahoo.fr

    2009-03-20

    The crystallographic and magnetic structures of polycrystalline Ba{sub 2}(Fe,W){sub 2}O{sub 6} and Ba{sub 2}(Fe,W{sub 0.5}Mo{sub 0.5}){sub 2}O{sub 6} double-perovskites have been investigated by X-ray and neutron powder diffraction (NPD), magnetization and Moessbauer spectroscopy. The samples were synthesized by conventional solid-state reaction at temperatures about 1273 K. The compounds crystallize in the cubic structure with space group Fm3-barm. The magnetic structures were determined by neutron powder diffraction between 5 K and 310 K. Evidence for an antiferromagnetic behavior has been observed for Ba{sub 2}(Fe,W){sub 2}O{sub 6} with T{sub N} = 24.7 K and a two-phase separation for Ba{sub 2}(Fe,W{sub 0.5}Mo{sub 0.5}){sub 2}O{sub 6} into an antiferromagnetic structure of the W-type with T{sub N} = 24.7 K and the ferromagnetic Mo-type with T{sub C} = 270 K.

  1. High Precision Magnetic Field Scanning System for the New Muon g-2 Experiment

    Science.gov (United States)

    Hong, Ran; Muon g-2 collaboration Collaboration

    2017-01-01

    The New Muon g-2 Experiment (E989) at Fermilab will measure the anomalous magnetic moment of muon aμ aiming at a precision of 140 ppb. This new experiment will shed light on the long-standing 3.5 standard deviation between the previous muon g-2 measurement (E821) at Brookhaven National Laboratory and the Standard Model calculation, and potentially discover new physics. The New Muon g-2 Experiment measures the precession frequency of muon in a uniform magnetic field, and the magnetic field experienced by the muons needs to be measured with a precision better than 70 ppb. For the measurement of the magnetic field in the muon storage region, the former trolley system from E821 with 17 NMR probes was refurbished and upgraded with new electronics, probes and a modern motion control system. A test solenoid magnet was set up at Argonne National Laboratory for calibrating the NMR probes and the precision studies of systematic uncertainties. In this presentation, we will describe the trolley motion control scheme, the trolley position measurement methods, the electronic system for activating and reading the NMR probes and the test solenoid facility.

  2. Measurement and tricubic interpolation of the magnetic field for the OLYMPUS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Bernauer, J.C. [Massachusetts Institute of Technology, Laboratory for Nuclear Science, Cambridge, MA (United States); Diefenbach, J. [Hampton University, Hampton, VA (United States); Elbakian, G. [Alikhanyan National Science Laboratory (Yerevan Physics Institute), Yerevan (Armenia); Gavrilov, G. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Goerrissen, N. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Hasell, D.K.; Henderson, B.S. [Massachusetts Institute of Technology, Laboratory for Nuclear Science, Cambridge, MA (United States); Holler, Y. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Karyan, G. [Alikhanyan National Science Laboratory (Yerevan Physics Institute), Yerevan (Armenia); Ludwig, J. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Marukyan, H. [Alikhanyan National Science Laboratory (Yerevan Physics Institute), Yerevan (Armenia); Naryshkin, Y. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); O' Connor, C.; Russell, R.L.; Schmidt, A. [Massachusetts Institute of Technology, Laboratory for Nuclear Science, Cambridge, MA (United States); Schneekloth, U. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Suvorov, K.; Veretennikov, D. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation)

    2016-07-01

    The OLYMPUS experiment used a 0.3 T toroidal magnetic spectrometer to measure the momenta of outgoing charged particles. In order to accurately determine particle trajectories, knowledge of the magnetic field was needed throughout the spectrometer volume. For that purpose, the magnetic field was measured at over 36,000 positions using a three-dimensional Hall probe actuated by a system of translation tables. We used these field data to fit a numerical magnetic field model, which could be employed to calculate the magnetic field at any point in the spectrometer volume. Calculations with this model were computationally intensive; for analysis applications where speed was crucial, we pre-computed the magnetic field and its derivatives on an evenly spaced grid so that the field could be interpolated between grid points. We developed a spline-based interpolation scheme suitable for SIMD implementations, with a memory layout chosen to minimize space and optimize the cache behavior to quickly calculate field values. This scheme requires only one-eighth of the memory needed to store necessary coefficients compared with a previous scheme (Lekien and Marsden, 2005 [1]). This method was accurate for the vast majority of the spectrometer volume, though special fits and representations were needed to improve the accuracy close to the magnet coils and along the toroidal axis.

  3. Simulating Magnetic Reconnection Experiment (MRX) with a Guide Field using Fluid Code, HiFi

    Science.gov (United States)

    Budner, Tamas; Chen, Yangao; Meier, Eric; Ji, Hantao; MRX Team

    2015-11-01

    Magnetic reconnection is a phenomenon that occurs in plasmas when magnetic field lines effectively ``break'' and reconnect resulting in a different topological configuration. In this process, energy that was once stored in the magnetic field is transfered into the thermal velocity of the particles, effectively heating the plasma. MRX at the Princeton Plasma Physics Laboratory creates the conditions under which reconnection can occur by initially ramping the current in two adjacent coils and then rapidly decreasing with and without a guide magnetic field along the reconnecting current. We simulate this experiment using a fluid code called HiFi, an implicit and adaptive high order spectral element modeling framework, and compare our results to experimental data from MRX. The purpose is to identify physics behind the observed reconnection process for the field line break and the resultant plasma heating.

  4. Experimental results from magnetized-jet experiments executed at the Jupiter Laser Facility

    Science.gov (United States)

    Manuel, M. J.-E.; Kuranz, C. C.; Rasmus, A. M.; Klein, S. R.; MacDonald, M. J.; Trantham, M. R.; Fein, J. R.; Belancourt, P. X.; Young, R. P.; Keiter, P. A.; Drake, R. P.; Pollock, B. B.; Park, J.; Hazi, A. U.; Williams, G. J.; Chen, H.

    2015-12-01

    Recent experiments at the Jupiter Laser Facility investigated magnetization effects on collimated plasma jets. Laser-irradiated plastic-cone-targets produced collimated, millimeter-scale plasma flows as indicated by optical interferometry. Proton radiography of these jets showed no indication of strong, self-generated magnetic fields, suggesting a dominantly hydrodynamic collimating mechanism. Targets were placed in a custom-designed solenoid capable of generating field strengths up to 5 T. Proton radiographs of the well-characterized B-field, without a plasma jet, suggested an external source of trapped electrons that affects proton trajectories. The background magnetic field was aligned with the jet propagation direction, as is the case in many astrophysical systems. Optical interferometry showed that magnetization of the plasma results in disruption of the collimated flow and instead produces a hollow cavity. This result is a topic of ongoing investigation.

  5. Quench calculations for the superconducting dipole magnet of CBM experiment at FAIR

    Science.gov (United States)

    Kurilkin, P.; Akishin, P.; Bychkov, A.; Floch, E.; Gusakov, Yu.; Ladygin, V.; Malakhov, A.; Moritz, G.; Ramakers, H.; Senger, P.; Shabunov, A.; Szwangruber, P.; Toral, F.

    2016-08-01

    The scientific mission of the Compressed Baryonic Matter (CBM) experiment is the study of the nuclear matter properties at the high baryon densities in heavy ion collisions at the Facility of Antiproton and Ion Research (FAIR) in Darmstadt. The 5.15 MJ superconducting dipole magnet will be used in the silicon tracking system of the CBM detector. It will provide a magnetic field integral of 1 Tm which is required to obtain a momentum resolution of 1% for the track reconstruction. This paper presents quench modeling and evaluation of candidate protection schemes for the CBM dipole magnet. Two quench programs based on finite-difference method were used in simulation. One of them is currently used at GSI, and the other based on CIEMAT (Madrid, Spain) was modified to perform quench calculation for the CBM magnet.

  6. Neutron-scattering experiment on solid 3He

    Science.gov (United States)

    Mat'aš, S.; Bat'ko, I.; Boyko, V.; Schöttl, S.; Siemensmeyer, K.; Raasch, S.; Radulov, I.; Adams, E. D.; Scherline, T. E.

    The central aim of our work is the characterisation of magnetic and crystallographic properties of solid 3He on a microscopic scale. This can only be achieved using neutron-diffraction techniques. The potential of neutron methods in magnetism and their application to nuclear magnetism is well known. They were very successful in the recent investigation of spontaneous nuclear order in copper and silver. The high neutron absorption cross section makes the application of neutron diffraction in solid 3He very difficult - but a careful feasibility study of diffraction experiments shows that new results of fundamental importance in the field of magnetism may be gained.

  7. The application of in-situ 3D X-ray diffraction in annealing experiments: First interpretation of substructure development in deformed NaCl

    DEFF Research Database (Denmark)

    Borthwick, Verity; Schmidt, Søren; Piazolo, Sandra;

    2012-01-01

    In-situ 3D X-ray diffraction (3DXRD) annealing experiments were conducted at the ID-11 beamline at the European Synchrotron Radiation Facility in Grenoble. This allowed us to nondestructively document and subsequently analyse the development of substructures during heating, without the influence...... of surface effects. A sample of deformed single crystal halite was heated to between 260-400 °. Before and after heating a volume of 500 by 500 by 300 μm was mapped using a planar beam, which was translated over the sample volume at intervals of 5-10 μm in the vertical dimension. In the following we present...... partially reconstructed orientation maps over one layer before and after heating for 240min at 260 °. Additional small syn-heating "maps" over a constrained sample rotation of 12-30°. The purpose of this was to illuminate a few reflections from 1 or 2 subgrains and follow their evolution during heating...

  8. Structure enhancement methodology using theory and experiment: gas-phase molecular structures using a dynamic interaction between electron diffraction, molecular mechanics, and ab initio data.

    Science.gov (United States)

    Kafka, Graeme R; Masters, Sarah L; Rankin, David W H

    2007-07-01

    A new method of incorporating ab initio theoretical data dynamically into the gas-phase electron diffraction (GED) refinement process has been developed to aid the structure determination of large, sterically crowded molecules. This process involves calculating a set of differences between parameters that define the positions of peripheral atoms (usually hydrogen), as determined using molecular mechanics (MM), and those which use ab initio methods. The peripheral-atom positions are then updated continually during the GED refinement process, using MM, and the returned positions are modified using this set of differences to account for the differences between ab initio and MM methods, before being scaled back to the average parameters used to define them, as refined from experimental data. This allows the molecule to adopt a completely asymmetric structure if required, without being constrained by the MM parametrization, whereas the calculations can be performed on a practical time scale. The molecular structures of tri-tert-butylphosphine oxide and tri-tert-butylphosphine imide have been re-examined using this new technique, which we call SEMTEX (Structure Enhancement Methodology using Theory and EXperiment).

  9. Effects of Q&P Processing Conditions on Austenite Carbon Enrichment Studied by In Situ High-Energy X-ray Diffraction Experiments

    Directory of Open Access Journals (Sweden)

    Sébastien Yves Pierre Allain

    2017-06-01

    Full Text Available We report the first ultra-fast time-resolved quantitative information on the quenching and partitioning process of conventional high-strength steel by an in situ high-energy X-ray diffraction (HEXRD experiment. The time and temperature evolutions of phase fractions, their carbon content, and internal stresses were determined and discussed for different process parameters. It is shown that the austenite-to-martensite transformation below the martensite start temperature Ms is followed by a stage of fast carbon enrichment in austenite during isothermal holding at both 400 and 450 °C. The analysis proposed supports the concurrent bainite transformation and carbon diffusion from martensite to austenite as the main mechanisms of this enrichment. Furthermore, we give evidence that high hydrostatic tensile stresses in austenite are produced during the final quenching, and must be taken into account for the estimation of the carbon content in austenite. Finally, a large amount of carbon is shown to be trapped in the microstructure.

  10. Cogging torque optimization in surface-mounted permanent-magnet motors by using design of experiment

    Energy Technology Data Exchange (ETDEWEB)

    Abbaszadeh, K., E-mail: Abbaszadeh@kntu.ac.ir [Department of Electrical Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Rezaee Alam, F.; Saied, S.A. [Department of Electrical Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of)

    2011-09-15

    Graphical abstract: Magnet segment arrangement in cross section view of one pole for PM machine. Display Omitted Highlights: {yields} Magnet segmentation is an effective method for the cogging torque reduction. {yields} We have used the magnet segmentation method based on the design of experiment. {yields} We have used the RSM design of the design of experiment method. {yields} We have solved optimization via surrogate models like the polynomial regression. {yields} A significant reduction of the cogging torque is obtained by using RSM. - Abstract: One of the important challenges in design of the PM electrical machines is to reduce the cogging torque. In this paper, in order to reduce the cogging torque, a new method for designing of the motor magnets is introduced to optimize of a six pole BLDC motor by using design of experiment (DOE) method. In this method the machine magnets consist of several identical segments which are shifted to a definite angle from each other. Design of experiment (DOE) methodology is used for a screening of the design space and for the generation of approximation models using response surface techniques. In this paper, optimization is often solved via surrogate models, that is, through the construction of response surface models (RSM) like polynomial regression. The experiments were performed based on the response surface methodology (RSM), as a statistical design of experiment approach, in order to investigate the effect of parameters on the response variations. In this investigation, the optimal shifting angles (factors) were identified to minimize the cogging torque. A significant reduction of cogging torque can be achieved with this approach after only a few evaluations of the coupled FE model.

  11. Electromagnetic characterization of the 990 ton gapless magnets for the OPERA experiment

    CERN Document Server

    Cazes, A; Dulach, B; Iungo, F; Incurvati, M; Orecchini, D; Peiro, G; Sanelli, C; Terranova, F; Ventura, M

    2007-01-01

    The instrumented targets of the OPERA neutrino experiment are complemented by two massive spectrometers based on gapless iron magnets. In 2006, a systematic assessment of their electromagnetic properties have been carried out. In this document, we report the results of such characterization and demonstrate that the achieved performance fulfill the physics requirements for the study of νμ→ντ oscillations.

  12. A New Density Operator Formalism for Describing Nuclear Magnetic Resonance Experiments

    Institute of Scientific and Technical Information of China (English)

    林东海; 吴钦义

    1994-01-01

    A density operator formalism has been proposed to describe the evolution of two-spin-1/2 systems in nuclear magnetic resonance experiments:The formalism is particularly convenient and has distinct physical meaning for describing the evolution of spin systems under the Hamiltonian containing non-commutable terms. Some examples are presented to demonstrate the new formalism.

  13. Transrectal ultrasonography and magnetic resonance imaging in the staging of rectal cancer. Effect of experience

    DEFF Research Database (Denmark)

    Rafaelsen, Søren R; Sørensen, Torben; Jakobsen, Anders

    2008-01-01

    OBJECTIVE: To evaluate the effect of experience on preoperative staging of rectal cancer using magnetic resonance imaging (MRI) and transrectal ultrasound (TRUS). MATERIAL AND METHODS: From January 2002 to May 2006, 134 consecutive patients with biopsy-proven rectal cancer were examined with a 1....... In addition to this supervision, the person responsible for staging should be trained through a defined training programme....

  14. Coupled fluid-flow and magnetic-field simulation of the Riga dynamo experiment

    NARCIS (Netherlands)

    Kenjereš, S.; Hanjalić, K.; Renaudier, S.; Stefani, F.; Gerbeth, G.; Gailitis, A.

    2006-01-01

    Magnetic fields of planets, stars, and galaxies result from self-excitation in moving electroconducting fluids, also known as the dynamo effect. This phenomenon was recently experimentally confirmed in the Riga dynamo experiment [ A. Gailitis et al., Phys. Rev. Lett. 84, 4365 (2000) ; A. Gailitis et

  15. FLASH MHD simulations of experiments that study shock-generated magnetic fields

    Science.gov (United States)

    Tzeferacos, P.; Fatenejad, M.; Flocke, N.; Graziani, C.; Gregori, G.; Lamb, D. Q.; Lee, D.; Meinecke, J.; Scopatz, A.; Weide, K.

    2015-12-01

    We summarize recent additions and improvements to the high energy density physics capabilities in FLASH, highlighting new non-ideal magneto-hydrodynamic (MHD) capabilities. We then describe 3D Cartesian and 2D cylindrical FLASH MHD simulations that have helped to design and analyze experiments conducted at the Vulcan laser facility. In these experiments, a laser illuminates a carbon rod target placed in a gas-filled chamber. A magnetic field diagnostic (called a Bdot) employing three very small induction coils is used to measure all three components of the magnetic field at a chosen point in space. The simulations have revealed that many fascinating physical processes occur in the experiments. These include megagauss magnetic fields generated by the interaction of the laser with the target via the Biermann battery mechanism, which are advected outward by the vaporized target material but decrease in strength due to expansion and resistivity; magnetic fields generated by an outward expanding shock via the Biermann battery mechanism; and a breakout shock that overtakes the first wave, the contact discontinuity between the target material and the gas, and then the initial expanding shock. Finally, we discuss the validation and predictive science we have done for this experiment with FLASH.

  16. Biological Experiments in Microgravity Conditions Using Magnetic Micro- and Nano-Particles

    Science.gov (United States)

    Nechitailo, Galina S.; Kuznetsov, Anatoli; Kuznetsov, Oleg

    2016-07-01

    Gravity affects all living organisms on Earth, and plays a role in multiple processes in them. In microgravity conditions (e.g., on board of a spacecraft) many of these processes are disturbed, e.g., spatial orientation is lost, mass and heat exchange is distorted, many adaptive mechanisms no longer function, etc. Negation of these adverse effects by creation of pseudo-gravity to by centrifugation is complicated, expensive and unpractical. We propose to use naturally occurring magnetic heterogeneity of all living cells and high gradient magnetic fields as an alternative approach to negating the adverse effects of microgravity on living systems. In non-uniform magnetic field, magnetically heterogeneous objects experience a system of ponderomotive forces. For a weak magnetic particle, the net ponderomotive magnetic force: Fm = Δχ•V•grad(H2/2), where Δχ is the difference of susceptibilities of the particle and the surrounding media, V is the volume of the particle, grad(H2/2) is the dynamic factor of the magnetic field. We studied magnetic heterogeneity of plant gravity receptor cells, prepared and conducted experiments on board of the space station "Mir" on providing a gravity-like stimulus for flax seedlings using high gradient magnetic field ("Magnetogravistat" experiment). Later, a more sophisticated version of this experiment was flown on STS-107. These experiments provided new data on the mechanisms of plant gravity reception and created a method for substituting gravity for a living organism by a force of a different physical nature, to negate the adverse effects of microgravity. Since the ponderomotive force is proportional to the dynamic factor of the field grad(H2/2), the stronger the field, and the faster it changes over distance, the higher is the dynamic factor and the stronger the ponderomotive force. Therefore, in the small vicinity of a small ferromagnetic particle (preferably metallic micro or nano-particles), the forces are very significant

  17. High-pressure neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hongwu [Los Alamos National Laboratory

    2011-01-10

    This lecture will cover progress and prospect of applications of high-pressure neutron diffraction techniques to Earth and materials sciences. I will first introduce general high-pressure research topics and available in-situ high-pressure techniques. Then I'll talk about high-pressure neutron diffraction techniques using two types of pressure cells: fluid-driven and anvil-type cells. Lastly, I will give several case studies using these techniques, particularly, those on hydrogen-bearing materials and magnetic transitions.

  18. The effect of water on the structure and dynamics of spider silk and silk-like polymers studied by magnetic resonance and x-ray diffraction

    Science.gov (United States)

    Yang, Zhitong

    Due to its unique combination of tensile strength and elasticity, the dragline silk of the orb-weaving spider Nephila clavipes has attracted much attention. Most importantly, it has a high energy to break that is unparalleled in other fibers. Though the basis for the strength of the silk fiber has been uncovered, the molecular reason of the fiber's large shrinkage in water is unknown. This has been a major hurdle in the practical applications of the fiber, and to any man-made copy of this material. Small-angle X-ray scattering (SAXS) is used to probe of the long-range structures in the semicrystalline silk. Scattering patterns of wet and dry samples indicate that the crystalline regions stack along the fiber axis to form lamellar structures. These structures are sparsely dispersed in a softer matrix with a long spacing of 8.4 nm. This spacing increases reversibly by 4% when fibers are stretched by 10%, and shrinks to 5.8 nm when fibers shrink 45% in length on wetting. Solid-state nuclear magnetic resonance (NMR) experiments are performed to reveal the microscopic details of the dynamics in the silk. Cross-polarization magic-angle spinning 13C NMR demonstrates that a substantial fraction of the glycine, glutamine, tyrosine, serine, and leucine residues experience dramatic increases in the rate of large-amplitude reorientation at the protein backbone when fibers are wet. Variable temperature deuterium NMR measurements were carried out on silk samples that incorporate leucine deuterated at the methyl group. Results show that only a subset of these leucine residues is strongly affected by water. Quantitative analysis and chemical considerations suggest that the highly conserved YGGLGS(N)QGAGR blocks, only found in the dragline silk protein, play a major role in the supercontraction process. Protein sequences are proposed to produce artificial spider silk with similar mechanical properties, but without the undesired phenomenon of supercontraction. The spinning and

  19. Optical and magnetic properties of a transparent garnet film for atomic physics experiments

    Directory of Open Access Journals (Sweden)

    Mari Saito

    2016-12-01

    Full Text Available We investigated the optical and magnetic properties of a transparent magnetic garnet with a particular focus on its applications to atomic physics experiments. The garnet film used in this study was a magnetically soft material that was originally designed for a Faraday rotator at optical communication wavelengths in the near infrared region. The film had a thickness of 2.1 μm and a small optical loss at a wavelength of λ=780 nm resonant with Rb atoms. The Faraday effect was also small and, thus, barely affected the polarization of light at λ=780 nm. In contrast, large Faraday rotation angles at shorter wavelengths enabled us to visualize magnetic domains, which were perpendicularly magnetized in alternate directions with a period of 3.6 μm. We confirmed the generation of an evanescent wave on the garnet film, which can be used for the optical observation and manipulation of atoms on the surface of the film. Finally, we demonstrated a magnetic mirror for laser-cooled Rb atoms using the garnet film.

  20. Reference layer exchange in spin transfer torque experiment using magnetic-coated nanometric point contacts

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, R.O., E-mail: rafaelotoniel@gmail.com [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501-970 (Brazil); Baptista, D.L.; Heinemann, M.; Kuhn, M.F.; Schmidt, J.E.; Pereira, L.G. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS 91501-970 (Brazil)

    2012-09-15

    We investigate the importance of using nanotips on a point contact spin-transfer torque (STT) experiment. A systematic analysis comparing the STT in a magnetic thin film in current-perpendicular-to-plane (CPP) geometry sample for magnetic coated and uncoated tungsten nanotips is shown. The STT effect presents a reverse resistance to current behavior when using a magnetic coating layer on the nanotips. We demonstrate that the magnetic layer on the tip may assume the role of a polarizer layer. This effect opens up the possibility of exploiting simpler architectures in STT-based devices, such as STT-random access memory (STT-RAM). - Highlights: Black-Right-Pointing-Pointer We investigated the spin-transfer torque (STT) effect using point contacts. Black-Right-Pointing-Pointer Tungsten nanotips were fabricated by electrochemical process. Black-Right-Pointing-Pointer Influence of the use of magnetic coating tips on STT effect was studied. Black-Right-Pointing-Pointer We observed that the magnetic layer on the tip may assume the role of a polarizer layer.

  1. Optical and magnetic properties of a transparent garnet film for atomic physics experiments

    Science.gov (United States)

    Saito, Mari; Tajima, Ryoichi; Kiyosawa, Ryota; Nagata, Yugo; Shimada, Hiroyuki; Ishibashi, Takayuki; Hatakeyama, Atsushi

    2016-12-01

    We investigated the optical and magnetic properties of a transparent magnetic garnet with a particular focus on its applications to atomic physics experiments. The garnet film used in this study was a magnetically soft material that was originally designed for a Faraday rotator at optical communication wavelengths in the near infrared region. The film had a thickness of 2.1 μm and a small optical loss at a wavelength of λ =780 nm resonant with Rb atoms. The Faraday effect was also small and, thus, barely affected the polarization of light at λ =780 nm. In contrast, large Faraday rotation angles at shorter wavelengths enabled us to visualize magnetic domains, which were perpendicularly magnetized in alternate directions with a period of 3.6 μm. We confirmed the generation of an evanescent wave on the garnet film, which can be used for the optical observation and manipulation of atoms on the surface of the film. Finally, we demonstrated a magnetic mirror for laser-cooled Rb atoms using the garnet film.

  2. Laboratory experiments investigating magnetic field production via the Weibel instability in interpenetrating plasma flows

    Science.gov (United States)

    Huntington, Channing; Fiuza, Frederico; Ross, James Steven; Zylstra, Alex; Pollock, Brad; Drake, R. Paul; Froula, Dustin; Gregori, Gianluca; Kugland, Nathan; Kuranz, Carolyn; Levy, Matthew; Li, Chikang; Meinecke, Jena; Petrasso, Richard; Remington, Bruce; Ryutov, Dmitri; Sakawa, Youichi; Spitkovsky, Anatoly; Takabe, Hideke; Turnbull, David; Park, Hye-Sook

    2015-08-01

    Astrophysical collisionless shocks are often associated with the presence of strong magnetic fields in a plasma flow. The magnetic fields required for shock formation may either be initially present, for example in supernova remnants or young galaxies, or they may be self-generated in systems such as gamma-ray bursts (GRBs). In the case of GRB outflows, the intense magnetic fields are greater than those seeded by the GRB progenitor or produced by misaligned density and temperature gradients in the plasma flow (the Biermann-battery effect). The Weibel instability is one candidate mechanism for the generation of sufficiently strong fields to create a collisionless shock. Despite their crucial role in astrophysical systems, observation of the magnetic fields produced by Weibel instabilities in experiments has been challenging. Using a proton probe to directly image electromagnetic fields, we present evidence of Weibel-generated magnetic fields that grow in opposing, initially unmagnetized plasma flows from laser-driven laboratory experiments. Three-dimensional particle-in-cell simulations reveal that the instability efficiently extracts energy from the plasma flows, and that the self-generated magnetic energy reaches a few percent of the total energy in the system. This result demonstrates an experimental platform suitable for the investigation of a wide range of astrophysical phenomena, including collisionless shock formation in supernova remnants, large-scale magnetic field amplification, and the radiation signature from gamma-ray bursts.This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  3. Measurements of fusion neutrons from Magnetized Liner Inertial Fusion Experiments on the Z accelerator

    Science.gov (United States)

    Hahn, K. D.; Chandler, G. A.; Ruiz, C. L.; Gomez, M. R.; Slutz, S. A.; Sefkow, A. B.; Sinars, D. B.; Hansen, S. B.; Knapp, P. F.; Schmit, P. F.; Harding, E. C.; Awe, T. J.; Torres, J. A.; Jones, B.; Bur, J. A.; Cooper, G. W.; Styron, J. D.; Glebov, V. Yu.

    2015-11-01

    Strong evidence of thermonuclear neutron production has been observed during Magnetized Liner Inertial Fusion (MagLIF) experiments on the Z accelerator. So far, these experiments have utilized deuterium fuel and produced primary DD fusion neutron yields up to 2e12 with electron and ion stagnation temperatures in the 2-3 keV range. We present MagLIF neutron measurements and compare to other data and implosion simulations. In addition to primary DD and secondary DT yields and ion temperatures, other complex physics regarding the degree of fuel magnetization and liner density are elucidated by the neutron measurements. Neutron diagnostic development for deuterium and future deuterium-tritium fuel experiments are also discussed. Sandia is sponsored by the U.S. DOE's NNSA under contract DE-AC04-94AL85000.

  4. MAGNET

    CERN Multimedia

    B. Curé

    MAGNET During the winter shutdown, the magnet subsystems went through a full maintenance. The magnet was successfully warmed up to room temperature beginning of December 2008. The vacuum was broken later on by injecting nitrogen at a pressure just above one atmosphere inside the vacuum tank. This was necessary both to prevent any accidental humidity ingress, and to allow for a modification of the vacuum gauges on the vacuum tank and maintenance of the diffusion pumps. The vacuum gauges had to be changed, because of erratic variations on the measurements, causing spurious alarms. The new type of vacuum gauges has been used in similar conditions on the other LHC experiments and without problems. They are shielded against the stray field. The lubricants of the primary and diffusion pumps have been changed. Several minor modifications were also carried out on the equipment in the service cavern, with the aim to ease the maintenance and to allow possible intervention during operation. Spare sensors have been bough...

  5. Experiments on the transportation of a magnetized plasma stream in the GOL-3 facility

    Science.gov (United States)

    Postupaev, V. V.; Batkin, V. I.; Burdakov, A. V.; Ivanov, I. A.; Kuklin, K. N.; Mekler, K. I.; Rovenskikh, A. F.

    2016-04-01

    The program of the deep upgrade of the GOL-3 multiple-mirror trap is presented. The upgrade is aimed at creating a new GOL-NB open trap located at the GOL-3 site and intended to directly demonstrate the efficiency of using multiple-mirror magnetic cells to improve longitudinal plasma confinement in a gasdynamic open trap. The GOL-NB device will consist of a new central trap, adjoint cells with a multiple-mirror magnetic field, and end tanks (magnetic flux expanders). Plasma in the central trap will be heated by neutral beam injection with a power of up to 1.5 MW and duration of 1 ms. At present, physical experiments directed at developing plasma technologies that are novel for this facility are being carried out using the 6-m-long autonomous part of the GOL-3 solenoid. The aim of this work was to develop a method for filling the central trap with a low-temperature start plasma. Transportation of a plasma stream from an arc source over a distance of 3 m in a uniform magnetic field with an induction of 0.5-4.5 T is demonstrated. In these experiments, the axial plasma density was (1-4) × 1020 m-3 and the mirror ratio varied from 5 to 60. In general, the experiments confirmed the correctness of the adopted decisions for the start plasma source of the GOL-NB device.

  6. The generation and amplification of intergalactic magnetic fields in analogue laboratory experiments with high power lasers

    Science.gov (United States)

    Gregori, G.; Reville, B.; Miniati, F.

    2015-11-01

    The advent of high-power laser facilities has, in the past two decades, opened a new field of research where astrophysical environments can be scaled down to laboratory dimensions, while preserving the essential physics. This is due to the invariance of the equations of magneto-hydrodynamics to a class of similarity transformations. Here we review the relevant scaling relations and their application in laboratory astrophysics experiments with a focus on the generation and amplification of magnetic fields in cosmic environment. The standard model for the origin of magnetic fields is a multi stage process whereby a vanishing magnetic seed is first generated by a rotational electric field and is then amplified by turbulent dynamo action to the characteristic values observed in astronomical bodies. We thus discuss the relevant seed generation mechanisms in cosmic environment including resistive mechanism, collision-less and fluid instabilities, as well as novel laboratory experiments using high power laser systems aimed at investigating the amplification of magnetic energy by magneto-hydrodynamic (MHD) turbulence. Future directions, including efforts to model in the laboratory the process of diffusive shock acceleration are also discussed, with an emphasis on the potential of laboratory experiments to further our understanding of plasma physics on cosmic scales.

  7. Design of a Superconducting Magnet System for the AEGIS Experiment at CERN

    CERN Document Server

    Dudarev, A; ten Kate, H; Perini, D

    2011-01-01

    The new AEGIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) Experiment will be installed in the Antiproton Decelerator hall at CERN. The main goal is to measure the Earth's gravitational acceleration of antihydrogen atoms. The experiment consists of two high-homogeneity solenoids placed on the same axis. The 5 T magnet is part of a cylindrical Penning trap to catch and to accumulate antiprotons delivered by the decelerator. The antihydrogen is then produced in the 1 T region where sub-kelvin antiproton temperatures provided by the dilution refrigerator are required to form a slowly-moving beam of antihydrogen. The helium bath cooled superconducting magnets; the different traps and the dilution refrigerator are integrated in a common cryostat with an internal vacuum barrier between the insulating cryogenic vacuum and the very high beam vacuum. In addition, the magnet system has to guarantee a smooth transition between the 5 T and the 1 T magnetic field areas required for a loss-free transfer o...

  8. Active cancellation of stray magnetic fields in a Bose-Einstein condensation experiment

    Science.gov (United States)

    Dedman, C. J.; Dall, R. G.; Byron, L. J.; Truscott, A. G.

    2007-02-01

    A method of active field cancellation is described, which greatly reduces the stray magnetic field within the trap region of a Bose-Einstein condensation experiment. An array of six single-axis magnetic sensors is used to interpolate the field at the trap center, thus avoiding the impractical requirement of placing the sensor within the trap. The system actively suppresses all frequencies from dc to approximately 3000 Hz, and the performance is superior to conventional active Helmholtz cancellation systems. A method of reducing the field gradient, by driving the six Helmholtz coils independently, is also investigated.

  9. Characterization of large-area photomultipliers under low magnetic fields: Design and performance of the magnetic shielding for the Double Chooz neutrino experiment

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, E.; Cerrada, M.; Fernandez-Bedoya, C.; Gil-Botella, I. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain); Palomares, C., E-mail: mc.palomares@ciemat.e [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain); Rodriguez, I.; Toral, F.; Verdugo, A. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid (Spain)

    2010-09-21

    A precise quantitative measurement of the effect of low magnetic fields in Hamamatsu R7081 photomultipliers has been performed. These large-area photomultipliers will be used in the Double Chooz neutrino experiment. A magnetic shielding has been developed for these photomultipliers. Its design and performance is also reported in this paper.

  10. Diffractive processes in antiproton-proton collision at √s = 1.96 TeV in the D0 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Otec, Roman [Czech Technical Univ., Prague (Czech Republic)

    2006-01-01

    A first study of single diffractive central high-pT dijet events in p$\\bar{p}$ collisions at center-of-mass energy √s = 1.96 TeV is presented, using data recorded by the D0 detector at the Tevatron during RunIIa in 2002-2004. The total integrated luminosity corresponding to the data sample is 398 pb-1. A diffractive sample is selected using a rapidity gap approach. A precise definition of the rapidity gap constitutes the first part of the thesis. The rapidity gap is defined by means of two parts of the D0 detector--luminosity detectors and calorimeter. Luminosity detectors serve as a basic indicators of diffractive candidates and the calorimeter is used to confirm the low energy activity in the forward region (a rapidity gap). Presented studies of energy deposited in forward part of calorimeter by various types of events yield two rapidity gap definitions. Both of them use a fixed rapidity interval in calorimeter |η| ϵ [2.6,5.2] and introduce an upper limit on the energy deposited in this region. First definition, which corresponds to the lowest systematical errors, uses a limit of 10 GeV, an energy limit in the second definition is set to 3 GeV. This alternative definition corresponds to the lowest contamination of diffractive sample by non-diffractive events, on the other hand it is accompanied with rejection of high percentage of diffractive candidates. Using the gap definition dijet diffractive data are then selected and compared to inclusive dijet events in various distributions. The main focus is to measure the difference in azimuthal angles between two leading jets in events with at least two high pt central jets. This variable is sensitive to the dynamics of the process. Indeed, the results show the different behavior of ΔΦ distributions between the inclusive and diffractive samples. It is also shown that this difference is bigger for lower pT jets. Other distributions presented in the thesis show that most

  11. Magnetic and crystal structure correlations in PrMn 1.5Co 0.5Ge 2: a synchrotron diffraction study

    Science.gov (United States)

    Ehrenberg, H.; Dincer, I.; Elmali, A.; Elerman, Y.; Fuess, H.

    2002-12-01

    Structure details of PrMn 2- xCo xGe 2, x=0.5, with the tetragonal ThCr 2Si 2-type structure have been studied by high-resolution synchrotron powder diffraction. Unit cell parameters a and c, unit cell volume V, c/ a, (∂ a/∂ x) T and (∂ c/∂ x) T were determined from Rietveld refinements in the temperature range 10-300 K. The average composition =0.49(4) is determined based on a detailed diffraction profile analysis. Our measurements indicate three anomalies in the c/ a ratio, (∂ a/∂ x) T and (∂c/∂ x) T at a temperature of about 150 K, which is very close to the transition temperature from antiferromagnetic to ferromagnetic intralayer ordering.

  12. DIGITAL CALCULATION OF E. M. DIFFRACTION FROM APERTURE BLOCKING

    Science.gov (United States)

    DIFFRACTION, *DIGITAL COMPUTERS, *RADAR ANTENNAS, DETECTION, DEXTRINS , DIELECTRICS, ELECTROMAGNETIC FIELDS, MAGNETIC PROPERTIES, MEASUREMENT, NUMERICAL ANALYSIS, COMPUTER PROGRAMMING, RADAR CONFUSION REFLECTORS, SAMPLING.

  13. Neutron diffraction study of the pressure-induced magnetic ordering in the spin gap system TlCuCl sub 3

    CERN Document Server

    Oosawa, A; Kakurai, K; Fujisawa, M; Tanaka, H

    2003-01-01

    Neutron elastic scattering measurements have been performed under a hydrostatic pressure in order to investigate the spin structure of the pressure-induced magnetic ordering in the spin gap system TlCuCl sub 3. Below the ordering temperature T sub N = 16.9 K for the hydrostatic pressure P = 1.48 GPa, magnetic Bragg reflections were observed at reciprocal lattice points Q = (h, 0, l) with integer h and odd l, which are equivalent to those points with the lowest magnetic excitation energy at ambient pressure. This indicates that the spin gap close due to the applied pressure. The spin structure of the pressure-induced magnetic ordered state for P = 1.48 GPa was determined. (author)

  14. Crucial Experiments in Quantum Physics.

    Science.gov (United States)

    Trigg, George L.

    The six experiments included in this monography are titled Blackbody Radiation, Collision of Electrons with Atoms, The Photoelectric Effect, Magnetic Properties of Atoms, The Scattering of X-Rays, and Diffraction of Electrons by a Crystal Lattice. The discussion provides historical background by giving description of the original experiments and…

  15. Flow dynamics and magnetic induction in the von-Karman plasma experiment

    CERN Document Server

    Plihon, Nicolas; Palermo, Francesco; Morales, Jorge A; Bos, Wouter; Godeferd, Fabien S; Bourgoin, Mickaël; Pinton, Jean-François; Moulin, M; Aanesland, Ane

    2014-01-01

    The von-Karman plasma experiment is a novel versatile experimental device designed to explore the dynamics of basic magnetic induction processes and the dynamics of flows driven in weakly magnetized plasmas. A high-density plasma column (10^16 - 10^19 particles.m^-3) is created by two radio-frequency plasma sources located at each end of a 1 m long linear device. Flows are driven through JxB azimuthal torques created from independently controlled emissive cathodes. The device has been designed such that magnetic induction processes and turbulent plasma dynamics can be studied from a variety of time-averaged axisymmetric flows in a cylinder. MHD simulations implementing volume-penalization support the experimental development to design the most efficient flow-driving schemes and understand the flow dynamics. Preliminary experimental results show that a rotating motion of up to nearly 1 km/s is controlled by the JxB azimuthal torque.

  16. Magnetic monopole searches with the MoEDAL experiment at the LHC

    CERN Document Server

    Pinfold, J; Lacarrère, D; Mermod, P; Katre, A

    2014-01-01

    The magnetic monopole appears in theories of spontaneous ga uge symmetry breaking and its existence would explain the quantisation of electric charg e. MoEDAL is the latest approved LHC experiment, designed to search directly for monopoles. It h as now taken data for the first time. The MoEDAL detectors are based on two complementary techniq ues: nuclear-track detectors are sensitive to the high-ionisation signature expected fr om a monopole, and the new magnetic monopole trapper (MMT) relies on the stopping and trapping o f monopoles inside an aluminium array which is then analysed with a superconducting magneto meter. Preliminary results obtained with a subset of the MoEDAL MMT test array deployed in 2012 are presented, where monopoles with charge above the fundamental unit magnetic charge or ma ss above 1.5 TeV are probed for the first time at the LHC

  17. Fetal magnetic resonance imaging: jumping from 1.5 to 3 tesla (preliminary experience)

    Energy Technology Data Exchange (ETDEWEB)

    Victoria, Teresa [The Children' s Hospital of Philadelphia, Radiology Department, Center for Fetal Diagnosis and Treatment, Philadelphia, PA (United States); Jaramillo, Diego; Roberts, Timothy Paul Leslie; Zarnow, Deborah; Johnson, Ann Michelle; Delgado, Jorge; Vossough, Arastoo [The Children' s Hospital of Philadelphia, Radiology Department, Philadelphia, PA (United States); Rubesova, Erika [Stanford University, Department of Radiology, Lucile Packard Children' s Hospital, Stanford, CA (United States)

    2014-04-15

    Several attempts have been made at imaging the fetus at 3 T as part of the continuous search for increased image signal and better anatomical delineation of the developing fetus. Until very recently, imaging of the fetus at 3 T has been disappointing, with numerous artifacts impeding image analysis. Better magnets and coils and improved technology now allow imaging of the fetus at greater magnetic strength, some hurdles in the shape of imaging artifacts notwithstanding. In this paper we present the preliminary experience of evaluating the developing fetus at 3 T and discuss several artifacts encountered and techniques to decrease them, as well as safety concerns associated with scanning the fetus at higher magnetic strength. (orig.)

  18. Passive control experiment of building with spacious first story by magnet-friction energy dissipation device

    Institute of Scientific and Technical Information of China (English)

    LI Qing-xiang; WANG Wei

    2005-01-01

    Based on the former performance capacity experiments of the magnet-friction energy dissipation devices, including the permanent magnet-friction energy dissipation device (PMF) and electromagnet-friction energy dissipation devices ( EMF), a 5-story steel frame model with spacious first story is designed and made according to a scale of 1/4. The magnet-friction energy dissipation devices can realize continuously varied controlling force, with rapid response and reverse recognition. Therefore, they overcome shortcomings usually found in energy dissipation devices whose force models are invariable. The two kinds of devices were fixed on the flexible first story of the structure model, and the shaking table tests have been carried out, respectively. In these tests,the performance of the devices and their effectiveness in structural control were confirmed. In this paper, the test results and analysis are discussed.

  19. Experiment of dynamic property and transient magnetic effects of coal during deformation and fracture

    Institute of Scientific and Technical Information of China (English)

    LI Cheng-wu; WEI Shan-yang; WANG Xue-ying; LIU Ji-kun; LEI Dong-ji

    2012-01-01

    Combining separated SHPB test device of φ50 mm with ZDKT-type 1 transient magnetic resonance test system,long drop bar of 400 mm was used to impact coal specimens at four different speeds:1.275,3.287,6.251,and 7.404 m/s.The change in waveform,the dynamic mechanical properties,and the generated effect of transient field during the coal deformation and fracture under the loads were discussed and analyzed.While magnetic signals during the coal fracture firstly needed EEMD,decomposition then had a FFT with Data Demon.The main results of the experiment are the following:the main frequency of magnetic signals was between 220 and 450 kHz and the instantaneous frequency during the damage of coal would have the instantaneous jump.

  20. Real-Time Analysis of Magnetic Hyperthermia Experiments on Living Cells under a Confocal Microscope.

    Science.gov (United States)

    Connord, Vincent; Clerc, Pascal; Hallali, Nicolas; El Hajj Diab, Darine; Fourmy, Daniel; Gigoux, Véronique; Carrey, Julian

    2015-05-01

    Combining high-frequency alternating magnetic fields (AMF) and magnetic nanoparticles (MNPs) is an efficient way to induce biological responses through several approaches: magnetic hyperthermia, drug release, controls of gene expression and neurons, or activation of chemical reactions. So far, these experiments cannot be analyzed in real-time during the AMF application. A miniaturized electromagnet fitting under a confocal microscope is built, which produces an AMF of frequency and amplitude similar to the ones used in magnetic hyperthermia. AMF application induces massive damages to tumoral cells having incorporated nanoparticles into their lysosomes without affecting the others. Using this setup, real-time analyses of molecular events occurring during AMF application are performed. Lysosome membrane permeabilization and reactive oxygen species production are detected after only 30 min of AMF application, demonstrating they occur at an early stage in the cascade of events leading eventually to cell death. Additionally, lysosomes self-assembling into needle-shaped organization under the influence of AMF is observed in real-time. This experimental approach will permit to get a deeper insight into the physical, molecular, and biological process occurring in several innovative techniques used in nanomedecine based on the combined use of MNPs and high-frequency magnetic fields. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Turbulent magnetic Prandtl numbers obtained with MHD Taylor-Couette flow experiments

    CERN Document Server

    Gellert, M

    2008-01-01

    The stability problem of MHD Taylor-Couette flows with toroidal magnetic fields is considered in dependence on the magnetic Prandtl number. Only the most uniform (but not current-free) field with B\\_in = B\\_out has been considered. For high enough Hartmann numbers the toroidal field is always unstable. Rigid rotation, however, stabilizes the magnetic (kink-)instability. The axial current which drives the instability is reduced by the electromotive force induced by the instability itself. Numerical simulations are presented to probe this effect as a possibility to measure the turbulent conductivity in a laboratory. It is shown numerically that in a sodium experiment (without rotation) an eddy diffusivity 4 times the molecular diffusivity appears resulting in a potential difference of ~34 mV/m. If the cylinders are rotating then also the eddy viscosity can be measured. Nonlinear simulations of the instability lead to a turbulent magnetic Prandtl number of 2.1 for a molecular magnetic Prandtl number of 0.01. The...

  2. Magnetic and Langmuir Probe Measurements on the Plasmoid Thruster Experiment (PTX)

    Science.gov (United States)

    Koelfgen, Syri J.; Eskridge, Richard; Lee, Michael H.; Martin, Adam; Hawk, Clark W.; Fimognan, Peter

    2004-01-01

    The Plasmoid Thruster Experiment (PTX) operates by inductively producing plasmoids in a conical theta-pinch coil and ejecting them at high velocity. A plasmoid is a plasma with an imbedded closed magnetic field structure. The shape and magnetic field structure of the translating plasmoids have been measured with of an array of magnetic field probes. Six sets of two B-dot probes were constructed for measuring B(sub z) and B(sub theta), the axial and azimuthal components of the magnetic field. The probes are wound on a square G10 form, and have an average (calibrated) NA of 9.37 x l0(exp -5) square meters, where N is the number of turns and A is the cross-sectional area. The probes were calibrated with a Helmholtz coil, driven by a high-voltage pulser to measure NA, and by a signal generator to determine the probe's frequency response. The plasmoid electron number density n(sub e) electron temperature T(sub e), and velocity ratio v/c(sub m), (where v is the bulk plasma flow velocity and c(sub m), is the ion thermal speed) have also been measured with a quadruple Langmuir probe. The Langmuir probe tips are 10 mm long, 20-mil diameter stainless steel wire, housed in a 6-inch long 4-bore aluminum rod. Measurements on PTX with argon and hydrogen from the magnetic field probes and quadruple Langmuir probe will be presented in this paper.

  3. Design and Status of the Dipole Spectrometer Magnet for the ALICE Experiment

    CERN Document Server

    Bartenev, V D; Datskov, V I; Koshurnikov, E; Shabounov, A; Shishov, Yu A; Swoboda, Detlef; Vodopyanov, A S

    2000-01-01

    Proposal of abstract for MT16, Tallahesse, Florida, 26th September to 2nd October 1999.A large Dipole Magnet is required for the Muon Arm Spectrometer of the ALICE experiment at the LHC.The absence of strong requirements on the symmetry and homogeneity of the magnetic field has lead to a design dominated by economic and feasibility considerations.In March 1997 the decision was taken to build a resistive dipole magnet for the muon spectrometer of the ALICE experiment. Since then, design work has been pursued in JINR/Russia and at CERN. While a common concept has been adopted for the construction of the steel core, two different proposals have been made for the manufacturing technology of the excitation coils. In both cases, however, the conductor material will be Aluminium.The general concept of the dipole magnet is based on a window frame return yoke, fabricated from low carbon steel sheets. The flat vertical poles follow the defined acceptance angle of 9 degrees. The excitation coils are of saddle type. The ...

  4. Heat capacity and neutron diffraction studies on the frustrated magnetic Co{sub 2}(OH)(PO{sub 4}){sub 1-x}(AsO{sub 4}){sub x} [0{<=}x{<=}1] solid solution

    Energy Technology Data Exchange (ETDEWEB)

    Pedro, I. de, E-mail: depedrovm@unican.es [CITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Departamento de Quimica Inorganica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, 48080 Bilbao (Spain); Rojo, J.M. [Departamento de Quimica Inorganica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, 48080 Bilbao (Spain); Rodriguez Fernandez, J.; Sanchez Marcos, J. [CITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander (Spain); Fernandez-Diaz, M.T. [Institut Laue-Langevin, BP 156X, F-38042 Grenoble Cedex (France); Rojo, T. [Departamento de Quimica Inorganica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, 48080 Bilbao (Spain)

    2012-04-15

    The Co{sub 2}(OH)(PO{sub 4}){sub 1-x}(AsO{sub 4}){sub x} [0{<=}x{<=}1] solid solution exhibits a complex magnetic behaviour due to the bond-frustration in its magnetic structure. Heat capacity measurements of the (x=0.1-0.5) phases show a three-dimensional magnetic ordering ({lambda} anomaly) that shifts to lower temperatures and becomes broader as the AsO{sub 4}{sup 3-} content increases. For x=0.75, no significant feature was observed whereas for higher arsenate ion content, x=0.9 and 1, a small maximum was detected. The magnetic structures of solid solution are consistent with the existence of predominant antiferromagnetic superexchange interactions through the |OH| and |XO{sub 4}| (X=P and As) groups between the Co{sup +2} ions. The substitution of PO{sub 4}{sup 3-} by AsO{sub 4}{sup 3-} anions by more than 90% substantially modifies the magnetic exchange pathways in the solid solution, leading to an incommensurate antiferromagnetic structure in Co{sub 2}(OH)(PO{sub 4}){sub 1-x}(AsO{sub 4}){sub x} [x=0.9 and 1] phases. - Graphical abstract: Magnetic structures of Co{sub 2}(OH)(PO{sub 4}){sub 1-x}(AsO{sub 4}){sub x} [0{<=}x{<=}1]. The ordering of the magnetic moments of Co{sup 2+} is in c direction for the two crystallographic positions (dimers and chains) in all compounds. The unit cell is surrounded by a red line. Highlights: Black-Right-Pointing-Pointer Synthesis of a new adamite-type compounds, Co{sub 2}(OH)(PO{sub 4}){sub 1-x}(AsO{sub 4}){sub x} (0.1, 0.25, 0.5, 0.75, 0.9) phases. Black-Right-Pointing-Pointer Co{sub 2}(OH)(PO{sub 4}){sub 1-x}(AsO{sub 4}){sub x} (0-1) solid solution; magnetic frustrated system. Black-Right-Pointing-Pointer High resolution neutron powder diffraction to determine the crystal structures. Black-Right-Pointing-Pointer Incommensurate magnetic structures at low temperature. Black-Right-Pointing-Pointer Magnetostructural correlations in cobalt-based Co{sub 2}(OH)XO{sub 4} (X=P and As) insulation compounds.

  5. Utilisation of the magnetic sensor in a smartphone for facile magnetostatics experiment: magnetic field due to electrical current in straight and loop wires

    Science.gov (United States)

    Septianto, R. D.; Suhendra, D.; Iskandar, F.

    2017-01-01

    This paper reports on the result of a research into the utilisation of a smartphone for the study of magnetostatics on the basis of experiments. The use of such a device gives great measurement result and thus it can replace magnetic sensor tools that are relatively expensive. For the best experimental result, firstly the position of the magnetic sensor in the smartphone has to be considered by way of value mapping of a magnetic field due to permanent magnet. The magnetostatics experiment investigated in this research was the measurement of magnetic field due to electrical currents in two shapes of wire, straight and looped. The current flow, the distance between the observation point and the wire, and the diameter of the loop were the variable parameters investigated to test the smartphone’s capabilities as a measurement tool. To evaluate the experimental results, the measured data were compared with theoretical values that were calculated by using both an analytical and a numerical approach. According to the experiment results, the measured data had good agreement with the results from the analytical and the numerical approach. This means that the use of the magnetic sensor in a smartphone in physics experiments is viable, especially for magnetic field measurement.

  6. Conclusions from 12 Years Operational Experience of the Cryoplants for the Superconducting Magnets of the LEP Experiments

    CERN Document Server

    Barth, K; Delikaris, D; Passardi, Giorgio

    2002-01-01

    The Large Electron Positron Collider (LEP) has ended its last physics run in November 2000, and it is at present being dismantled to liberate the tunnel for the Large Hadron Collider (LHC) project to be completed by end of 2005. The cryogenic systems for the superconducting solenoid and focusing quadrupoles for the two LEP experiments, ALEPH and DELPHI, each supplying a cooling power of 800 W/4.5 K entropy equivalent, have accumulated more then 100'000 hours of running time. The paper summarises the 12 years cryogenic experience in the various operating modes: cool-down, steady state, recovery after energy fast dump, utilities failures and warm-up of the superconducting magnets. The detailed operation statistics is presented and compared to the other CERN cryogenic systems. Emphasis is given to the technical analysis of the fault conditions and of their consequences on the helium refrigeration production time in view of the future operation of the LHC cryogenics.

  7. The PVLAS experiment: measuring vacuum magnetic birefringence and dichroism with a birefringent Fabry-Perot cavity

    CERN Document Server

    Della Valle, F; Ejlli, A; Gastaldi, U; Messineo, G; Zavattini, G; Pengo, R; Ruoso, G

    2015-01-01

    Vacuum magnetic birefringence was predicted long time ago and is still lacking a direct experimental confirmation. Several experimental efforts are striving to reach this goal, and the sequence of results promises a success in the next few years. This measurement generally is accompanied by the search for hypothetical light particles that couple to two photons. The PVLAS experiment employs a sensitive polarimeter based on a high finesse Fabry-Perot cavity. In this paper we report on the latest experimental results of this experiment. The data are analysed taking into account the intrinsic birefringence of the dielectric mirrors of the cavity. Besides the limit on the vacuum magnetic birefringence, the measurements also allow the model-independent exclusion of new regions in the parameter space of axion-like and milli-charged particles. In particular, these last limits hold also for all types of neutrinos, resulting in a laboratory limit on their charge.

  8. Numerical modeling of laser-driven experiments aiming to demonstrate magnetic field amplification via turbulent dynamo

    Science.gov (United States)

    Tzeferacos, P.; Rigby, A.; Bott, A.; Bell, A. R.; Bingham, R.; Casner, A.; Cattaneo, F.; Churazov, E. M.; Emig, J.; Flocke, N.; Fiuza, F.; Forest, C. B.; Foster, J.; Graziani, C.; Katz, J.; Koenig, M.; Li, C.-K.; Meinecke, J.; Petrasso, R.; Park, H.-S.; Remington, B. A.; Ross, J. S.; Ryu, D.; Ryutov, D.; Weide, K.; White, T. G.; Reville, B.; Miniati, F.; Schekochihin, A. A.; Froula, D. H.; Gregori, G.; Lamb, D. Q.

    2017-04-01

    The universe is permeated by magnetic fields, with strengths ranging from a femtogauss in the voids between the filaments of galaxy clusters to several teragauss in black holes and neutron stars. The standard model behind cosmological magnetic fields is the nonlinear amplification of seed fields via turbulent dynamo to the values observed. We have conceived experiments that aim to demonstrate and study the turbulent dynamo mechanism in the laboratory. Here, we describe the design of these experiments through simulation campaigns using FLASH, a highly capable radiation magnetohydrodynamics code that we have developed, and large-scale three-dimensional simulations on the Mira supercomputer at the Argonne National Laboratory. The simulation results indicate that the experimental platform may be capable of reaching a turbulent plasma state and determining the dynamo amplification. We validate and compare our numerical results with a small subset of experimental data using synthetic diagnostics.

  9. Numerical modeling of laser-driven experiments aiming to demonstrate magnetic field amplification via turbulent dynamo

    Energy Technology Data Exchange (ETDEWEB)

    Tzeferacos, P. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637, USA; Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom; Rigby, A. [Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom; Bott, A. [Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom; Bell, A. R. [Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom; Bingham, R. [Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, United Kingdom; Department of Physics, University of Strathclyde, Glasgow G4 0NG, United Kingdom; Casner, A. [CEA, DAM, DIF, F-91297 Arpajon, France; Cattaneo, F. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637, USA; Churazov, E. M. [Max Planck Institute for Astrophysics, D-85741 Garching, Germany; Space Research Institute (IKI), Moscow 117997, Russia; Emig, J. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Flocke, N. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637, USA; Fiuza, F. [SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA; Forest, C. B. [Physics Department, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; Foster, J. [AWE, Aldermaston, Reading, West Berkshire, RG7 4PR, United Kingdom; Graziani, C. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637, USA; Katz, J. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA; Koenig, M. [Laboratoire pour l' Utilisation de Lasers Intenses, UMR7605, CNRS CEA, Université Paris VI Ecole Polytechnique, France; Li, C. -K. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Meinecke, J. [Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom; Petrasso, R. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA; Park, H. -S. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Remington, B. A. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Ross, J. S. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Ryu, D. [Department of Physics, UNIST, Ulsan 689-798, South Korea; Ryutov, D. [Lawrence Livermore National Laboratory, Livermore, California 94550, USA; Weide, K. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637, USA; White, T. G. [Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom; Reville, B. [School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN, United Kingdom; Miniati, F. [Department of Physics, ETH Zürich, CH-8093 Zürich, Switzerland; Schekochihin, A. A. [Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom; Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA; Gregori, G. [Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom; Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637, USA; Lamb, D. Q. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637, USA

    2017-03-22

    The universe is permeated by magnetic fields, with strengths ranging from a femtogauss in the voids between the filaments of galaxy clusters to several teragauss in black holes and neutron stars. The standard model behind cosmological magnetic fields is the nonlinear amplification of seed fields via turbulent dynamo to the values observed. We have conceived experiments that aim to demonstrate and study the turbulent dynamo mechanism in the laboratory. Here, we describe the design of these experiments through simulation campaigns using FLASH, a highly capable radiation magnetohydrodynamics code that we have developed, and large-scale three-dimensional simulations on the Mira supercomputer at the Argonne National Laboratory. The simulation results indicate that the experimental platform may be capable of reaching a turbulent plasma state and determining the dynamo amplification. We validate and compare our numerical results with a small subset of experimental data using synthetic diagnostics.

  10. The PVLAS experiment: measuring vacuum magnetic birefringence and dichroism with a birefringent Fabry-Perot cavity

    Energy Technology Data Exchange (ETDEWEB)

    Della Valle, Federico; Milotti, Edoardo [INFN, Trieste (Italy); Universita di Trieste, Dipt. di Fisica, Trieste (Italy); Ejlli, Aldo; Messineo, Giuseppe; Zavattini, Guido [INFN, Ferrara (Italy); Universita di Ferrara, Dipt. di Fisica e Scienze della Terra, Ferrara (Italy); Gastaldi, Ugo [INFN, Ferrara (Italy); Pengo, Ruggero; Ruoso, Giuseppe [INFN, Lab. Nazionale di Legnaro, Legnaro (Italy)

    2016-01-15

    Vacuum magnetic birefringence was predicted long time ago and is still lacking a direct experimental confirmation. Several experimental efforts are striving to reach this goal, and the sequence of results promises a success in the next few years. This measurement generally is accompanied by the search for hypothetical light particles that couple to two photons. The PVLAS experiment employs a sensitive polarimeter based on a high finesse Fabry-Perot cavity. In this paper we report on the latest experimental results of this experiment. The data are analysed taking into account the intrinsic birefringence of the dielectric mirrors of the cavity. Besides a new limit on the vacuum magnetic birefringence, the measurements also allow the model-independent exclusion of new regions in the parameter space of axion-like and milli-charged particles. In particular, these last limits hold also for all types of neutrinos, resulting in a laboratory limit on their charge. (orig.)

  11. Fusion-neutron measurements for magnetized liner inertial fusion experiments on the Z accelerator

    Science.gov (United States)

    Hahn, K. D.; Chandler, G. A.; Ruiz, C. L.; Cooper, G. W.; Gomez, M. R.; Slutz, S.; Sefkow, A. B.; Sinars, D. B.; Hansen, S. B.; Knapp, P. F.; Schmit, P. F.; Harding, E.; Jennings, C. A.; Awe, T. J.; Geissel, M.; Rovang, D. C.; Torres, J. A.; Bur, J. A.; Cuneo, M. E.; Glebov, V. Yu; Harvey-Thompson, A. J.; Herrman, M. C.; Hess, M. H.; Johns, O.; Jones, B.; Lamppa, D. C.; Lash, J. S.; Martin, M. R.; McBride, R. D.; Peterson, K. J.; Porter, J. L.; Reneker, J.; Robertson, G. K.; Rochau, G. A.; Savage, M. E.; Smith, I. C.; Styron, J. D.; Vesey, R. A.

    2016-05-01

    Several magnetized liner inertial fusion (MagLIF) experiments have been conducted on the Z accelerator at Sandia National Laboratories since late 2013. Measurements of the primary DD (2.45 MeV) neutrons for these experiments suggest that the neutron production is thermonuclear. Primary DD yields up to 3e12 with ion temperatures ∼2-3 keV have been achieved. Measurements of the secondary DT (14 MeV) neutrons indicate that the fuel is significantly magnetized. Measurements of down-scattered neutrons from the beryllium liner suggest ρRliner∼1g/cm2. Neutron bang times, estimated from neutron time-of-flight (nTOF) measurements, coincide with peak x-ray production. Plans to improve and expand the Z neutron diagnostic suite include neutron burn-history diagnostics, increased sensitivity and higher precision nTOF detectors, and neutron recoil-based yield and spectral measurements.

  12. Anomalous Heating and Plasmoid Formation in a Driven Magnetic Reconnection Experiment

    CERN Document Server

    Hare, J D; Lebedev, S V; Loureiro, N F; Ciardi, A; Burdiak, G C; Chittenden, J P; Clayson, T; Garcia, C; Niasse, N; Robinson, T; Smith, R A; Stuart, N; Suzuki-Vidal, F; Swadling, G F; Ma, J; Wu, J; Yang, Q

    2016-01-01

    We present a detailed study of magnetic reconnection in a quasi-two-dimensional pulsed-power driven laboratory experiment. Oppositely directed magnetic fields $(B=3$ T), advected by supersonic, sub-Alfv\\'enic carbon plasma flows $(V_{in}=50$ km/s), are brought together and mutually annihilate inside a thin current layer ($\\delta=0.6$ mm). Temporally and spatially resolved optical diagnostics, including interferometry, Faraday rotation imaging and Thomson scattering, allow us to determine the structure and dynamics of this layer, the nature of the inflows and outflows and the detailed energy partition during the reconnection process. We measure high electron and ion temperatures $(T_e=100$ eV, $T_i=600$ eV), far in excess of what can be attributed to classical (Spitzer) resistive and viscous dissipation. We observe the repeated formation and ejection of plasmoids, which we interpret as evidence of two-fluid effects in our experiment.

  13. Advances in structure research by diffraction methods

    CERN Document Server

    Brill, R

    1970-01-01

    Advances in Structure Research by Diffraction Methods reviews advances in the use of diffraction methods in structure research. Topics covered include the dynamical theory of X-ray diffraction, with emphasis on Ewald waves in theory and experiment; dynamical theory of electron diffraction; small angle scattering; and molecular packing. This book is comprised of four chapters and begins with an overview of the dynamical theory of X-ray diffraction, especially in terms of how it explains all the absorption and propagation properties of X-rays at the Bragg setting in a perfect crystal. The next

  14. Scoring sacroiliac joints by magnetic resonance imaging. A multiple-reader reliability experiment

    DEFF Research Database (Denmark)

    Landewe, Robert B.M.; Hermann, Kay Geert A; Van Der Heijde, Desiree M.F.M

    2005-01-01

    Magnetic resonance imaging (MRI) of the sacroiliac (SI) joints and the spine is increasingly important in the assessment of inflammatory activity and structural damage in clinical trials with patients with ankylosing spondylitis (AS). We investigated inter-reader reliability and sensitivity...... systems. Sensitivity to change differed per reader, but in general was somewhat better for the comprehensive SPARCC system. This experiment under 'real life,' far from optimal conditions demonstrates the feasibility of scoring exercises for method comparison, provides evidence for the reliability...

  15. Development of 2D/3D equilibrium codes for magnetically confined fusion experiments

    OpenAIRE

    2013-01-01

    The present work is the result of a three-year Ph.D. research project carried out at Consorzio RFX on magnetically confined plasmas. Research on controlled thermonuclear fusion is currently being pursued by many countries throughout the world, thanks to its promise of a relatively clean and abundant energy source. The next steps for the international community are the construction and operation of a large device, ITER, considered as the last fusion physics experiment with respect to the tokam...

  16. Scoring sacroiliac joints by magnetic resonance imaging. A multiple-reader reliability experiment

    DEFF Research Database (Denmark)

    Landewe, Robert B.M.; Hermann, Kay Geert A; Van Der Heijde, Desiree M.F.M

    2005-01-01

    Magnetic resonance imaging (MRI) of the sacroiliac (SI) joints and the spine is increasingly important in the assessment of inflammatory activity and structural damage in clinical trials with patients with ankylosing spondylitis (AS). We investigated inter-reader reliability and sensitivity...... systems. Sensitivity to change differed per reader, but in general was somewhat better for the comprehensive SPARCC system. This experiment under 'real life,' far from optimal conditions demonstrates the feasibility of scoring exercises for method comparison, provides evidence for the reliability...

  17. Oil Spill Remediation Using Magnetic Particles: An Experiment in Environmental Technology

    Science.gov (United States)

    Orbell, John D.; Godhino, Leroy; Bigger, Stephen W.; Nguyen, Thi Man; Ngeh, Lawrence N.

    1997-12-01

    A simple experiment is described in which the potential of commercially available steel pellets coated with polyethylene (PE) or poly(vinylchloride) (PVC) to remediate an oil spill is demonstrated. Polymer-coated particles are weighed, immersed in oil, magnetically harvested and the remaining oil is weighed in order to enable students to quantitatively investigate the adsorption process. The possibility of recycling the beads and reclaiming the oil is also demonstrated.

  18. Lorentz microscopy and small-angle electron diffraction study of magnetic textures in L a1 -xS rxMn O3 (0.15 magnetic anisotropy

    Science.gov (United States)

    Kotani, A.; Nakajima, H.; Harada, K.; Ishii, Y.; Mori, S.

    2016-07-01

    Magnetic textures in the ferromagnetic phases of L a1 -xS rxMn O3 for 0.15 magnetic textures characterized by stripe, plate-shaped, and cylindrical (magnetic bubble) domains were found. Two distinct types of magnetic stripe domains appeared in the orthorhombic structure with an inversion symmetry of L a0.825S r0.175Mn O3 , depending significantly on magnetocrystalline anisotropy. Based on in situ observations as functions of temperature and the strength of the external magnetic field, a magnetic field-temperature phase diagram was constructed, showing the stabilization of magnetic bubbles in the ferromagnetic phase of L a0.825S r0.175Mn O3 .

  19. MAGNET

    CERN Multimedia

    B. Curé

    During the winter shutdown, the magnet subsystems went through a full maintenance. The magnet was successfully warmed up to room temperature beginning of December 2008. The vacuum was broken later on by injecting nitrogen at a pressure just above one atmosphere inside the vacuum tank. This was necessary both to prevent any accidental humidity ingress, and to allow for a modification of the vacuum gauges on the vacuum tank and maintenance of the diffusion pumps. The vacuum gauges had to be changed, because of erratic variations on the measurements, causing spurious alarms. The new type of vacuum gauges has been used in similar conditions on the other LHC experiments and without problems. They are shielded against the stray field. The lubricants of the primary and diffusion pumps have been changed. Several minor modifications were also carried out on the equipment in the service cavern, with the aim to ease the maintenance and to allow possible intervention during operation. Spare sensors have been bought. Th...

  20. Cryogenic Considerations for Superconducting Magnet Design for the Material Plasma Exposure eXperiment

    Energy Technology Data Exchange (ETDEWEB)

    Duckworth, Robert C [ORNL; Demko, Dr. Jonathan A [LeTourneau University, Texas; Lumsdaine, Arnold [ORNL; Caughman, John B [ORNL; Goulding, Richard Howell [ORNL; McGinnis, William Dean [ORNL; Bjorholm, Thomas P [ORNL; Rapp, Juergen [ORNL

    2015-01-01

    In order to determine long term performance of plasma facing components such as diverters and first walls for fusion devices, next generation plasma generators are needed. A Material Plasma Exposure eXperiment (MPEX) has been proposed to address this need through the generation of plasmas in front of the target with electron temperatures of 1-15 eV and electron densities of 1020 to 1021 m-3. Heat fluxes on target diverters could reach 20 MW/m2. In order generate this plasma, a unique radio frequency helicon source and heating of electrons and ions through Electron Bernstein Wave (EBW) and Ion Cyclotron Resonance Heating (ICRH) has been proposed. MPEX requires a series of magnets with non-uniform central fields up to 2 T over a 5m length in the heating and transport region and 1 T uniform central field over a 1-m length on a diameter of 1.3 m. Given the field requirements, superconducting magnets are under consideration for MPEX. In order to determine the best construction method for the magnets, the cryogenic refrigeration has been analyzed with respect to cooldown and operational performance criteria for open-cycle and closed-cycle systems, capital and operating costs of these system, and maturity of supporting technology such as cryocoolers. These systems will be compared within the context of commercially available magnet constructions to determine the most economical method for MPEX operation. The current state of the MPEX magnet design including details on possible superconducting magnet configurations will be presented.

  1. Diffraction coherence in optics

    CERN Document Server

    Françon, M; Green, L L

    2013-01-01

    Diffraction: Coherence in Optics presents a detailed account of the course on Fraunhofer diffraction phenomena, studied at the Faculty of Science in Paris. The publication first elaborates on Huygens' principle and diffraction phenomena for a monochromatic point source and diffraction by an aperture of simple form. Discussions focus on diffraction at infinity and at a finite distance, simplified expressions for the field, calculation of the path difference, diffraction by a rectangular aperture, narrow slit, and circular aperture, and distribution of luminous flux in the airy spot. The book th

  2. In-situ grazing incidence X-ray diffraction measurements of relaxation in Fe/MgO/Fe epitaxial magnetic tunnel junctions during annealing

    Science.gov (United States)

    Eastwood, D. S.; Ali, M.; Hickey, B. J.; Tanner, B. K.

    2013-12-01

    The relaxation of Fe/MgO/Fe tunnel junctions grown epitaxially on (001) MgO substrates has been measured by in-situ grazing incidence in-plane X-ray diffraction during the thermal annealing cycle. We find that the Fe layers are fully relaxed and that there are no irreversible changes during annealing. The MgO tunnel barrier is initially strained towards the Fe but on annealing, relaxes and expands towards the bulk MgO value. The strain dispersion is reduced in the MgO by about 40% above 480 K post-annealing. There is no significant change in the "twist" mosaic. Our results indicate that the final annealing stage of device fabrication, crucial to attainment of high TMR, induces substantial strain relaxation at the MgO barrier/lower Fe electrode interface.

  3. Neutron diffraction study of the La1-xPrxMn2Si2 ( x=0.4, 0.7 and 1) compounds and the general description of the magnetic behavior of Mn in RMn2Ge2 and RMn2Si2

    Science.gov (United States)

    Dincer, I.; Elerman, Y.; Elmali, A.; Ehrenberg, H.; André, G.

    2007-06-01

    The magnetic structures of the La1-xPrxMn2Si2 ( x=0.4, 0.7 and 1) have been investigated by powder neutron diffraction between 2 and 308 K. According to magnetic measurements, the x=0.4 sample shows a typical SmMn2Ge2-like magnetic behavior. Neutron diffraction indicates a canted antiferromagnetic structure below 130 K and a canted ferromagnetic structure above 240 K. Between 130 and 240 K, the canted ferromagnetic and antiferromagnetic structures coexist. Since the magnetic moments of Mn atoms, the unit cell parameters and the scale parameters of the canted antiferromagnetism and canted ferromagnetism are highly correlated between 130 and 240 K, a special refinement procedure was introduced. The critical Mn-Mn value was determined as 2.87 A˚, and the spontaneous volume change and linear magnetostriction are derived. Neutron diffraction revealed a canted antiferromagnetic structure for La0.3Pr0.7Mn2Si2. A canted antiferromagnetic structure was also detected for PrMn2Si2 by neutron diffraction in contrast to previous reports of a collinear arrangement. The present results are compiled together with previous ones on RMn2Ge2 and RMn2Si2 (R: Y, La and rare-earth) compounds in two magnetic phase diagrams. These two graphics summarize the general magnetic behavior of Mn in the RMn2Ge2 and RMn2Si2 compounds.

  4. Optimization of the Loading Process of the QUIC Magnetic Trap for the Experiment of Bose-Einstein Condensation

    Institute of Scientific and Technical Information of China (English)

    CHEN Shuai; ZHOU Xiao-Ji; YANG Fan; XIA Lin; WANG Yi-Qiu; CHEN Xu-Zong

    2004-01-01

    @@ The magnetic quadrupole-Ioffe configuration (QUIC) trap in our Bose-Einstein condensation experiment is introduced. The magnetic trap loading process after laser cooling is analysed and the optimization of the loading process is studied experimentally. Calculation of the magnetic field explains the loss of the atoms during the loading process of the QUIC trap. The number of atoms loaded in the QUIC trap is increased by 40%o after optimization in comparison with the normal loading process.

  5. Octet Baryon Magnetic Moments from Lattice QCD: Approaching Experiment from the Three-Flavor Symmetric Point

    CERN Document Server

    Parreno, Assumpta; Tiburzi, Brian C; Wilhelm, Jonas; Chang, Emmanuel; Detmold, William; Orginos, Kostas

    2016-01-01

    Lattice QCD calculations with background magnetic fields are used to determine the magnetic moments of the octet baryons. Computations are performed at the physical value of the strange quark mass, and two values of the light quark mass, one corresponding to the SU(3) flavor-symmetric point, where the pion mass is ~ 800 MeV, and the other corresponding to a pion mass ~ 450 MeV. The moments are found to exhibit only mild pion-mass dependence when expressed in terms of appropriately chosen magneton units---the natural baryon magneton. This suggests that simple extrapolations can be used to determine magnetic moments at the physical point, and extrapolated results are found to agree with experiment within uncertainties. A curious pattern is revealed among the anomalous baryon magnetic moments which is linked to the constituent quark model, however, careful scrutiny exposes additional features. Relations expected to hold in the large-Nc limit of QCD are studied; and, in one case, the quark model prediction is sig...

  6. Ramp-rate limitation experiments in support of the TPX magnets

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, S.; Schultz, J.H.; Takayasu, Makoto; Michael, P.C. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Shen, S. [Lawrence Livermore National Lab., CA (United States); Vysotsky, V. [Kurchatov Inst., Moscow (Russian Federation); Warnes, W. [Oregon State Univ., Eugene, OR (United States)

    1995-12-31

    Fast magnetic field change is required for full-size tokamak reactors. The poloidal field magnets are usually ramped to full field at 1.2 T/s, and see pulsed fields of up to 20 T/s during plasma initiation. A new facility has been constructed at M.I.T. that simulates the expected operating conditions of the Tokamak Physics Experiment (TPX) magnets. New features in this facility include (1) a superconducting pulse coil that can superimpose high ramp-down rates, up to 25 T/s, (2 T in 80 msec) on a background field up to 5 T, (2) new power supplies that can supply high rates of dI/dt and dB/dt to the sample under test and the pulse coil, and (3) a forced-flow supercritical helium system that can simulate cooling conditions within the winding pack. The first sample tested in the facility is a 27-strand sub-cable, using 3.1:1 copper, noncopper ratio Nb{sub 3}Sn superconductor, typical of the strands to be used in ten of the poloidal field system magnets. This paper presents the first experimental results on the ramp rate limitation of the sub-size cable sample of TPX PF coil conductor. The transient stability at high ramp rate fields will be discussed.

  7. Experiments with low energy ion beam transport into toroidal magnetic fields

    CERN Document Server

    Joshi, N; Meusel, O; Ratzinger, U

    2016-01-01

    The stellarator-type storage ring for accumulation of multi- Ampere proton and ion beams with energies in the range of $100~AkeV$ to $1~AMeV$ is designed at Frankfurt university. The main idea for beam confinement with high transversal momentum acceptance was presented in EPAC2006. This ring is typically suited for experiments in plasma physics and nuclear astrophysics. The accumulator ring with a closed longitudinal magnetic field is foreseen with a strength up to $6-8~T$. The experiments with two room temperature 30 degree toroids are needed. The beam transport experiments in toroidal magnetic fields were first described in EPAC2008 within the framework of a proposed low energy ion storage ring. The test setup aims on developing a ring injection system with two beam lines representing the main beam line and the injection line. The primary beam line for the experiments was installed and successfully commissioned in 2009. A special diagnostics probe for \\textit{"in situ"} ion beam detection was installed.This...

  8. A soft magnetic material for power supply systems of high energy physics experiments

    Directory of Open Access Journals (Sweden)

    Ghisolfi E.

    2013-01-01

    Full Text Available Most of the high energy physics experiments require their detectors to be embedded in a high intensity magnetic field. In particular the biggest of them, ATLAS, running in the CERN Large Hadron Collider (LHC particle accelerator, generates a field of 2 T by means of a gigantic toroidal magnet working in open air. Its future phase 2 upgrade plans to move the DC/DC power supplies from the present positions on the external balconies directly on the detectors, where the field is of the order of 1 T. This presentation describes the development of samples made of special magnetic material for inductor cores suitable to work in such an environment. Starting from iron-silicon powders, at FN plant a plastic forming process, based on powder extrusion, injection moulding and sintering, was developed. To get the best compromise between the forming process requirements (good coupling among the metallic powder and the organic components to assure the right mouldability and the debinding and sintering conditions, several mixtures (with different percentages and kind of organic additives were experimented. A proper mould was designed and realized to get torous-shaped prototypes. The preliminary results of the physical-microstructural characterization performed on the first prototypes made will be shown.

  9. Magnetic flux compression experiments on the Z pulsed-power accelerator

    Science.gov (United States)

    McBride, R. D.; Gomez, M. R.; Hansen, S. B.; Jennings, C. A.; Bliss, D. E.; Knapp, P. F.; Schmit, P. F.; Awe, T. J.; Martin, M. R.; Sinars, D. B.; Greenly, J. B.; Intrator, T. P.; Weber, T. E.

    2014-10-01

    We report on the progress made to date for diagnosing magnetic flux compression on Z. Each experiment consisted of an initially solid Be or Al liner (cylindrical tube), which was imploded using Z's drive current (0-20 MA in 100 ns). The imploding liner compresses a 10-T axial seed field, Bz(0), supplied by an independently driven Helmholtz coil pair. Assuming perfect flux conservation, the axial field amplification should be well described by Bz (t) =Bz (0) × [ R (0) / R (t) ]2 , where R is the liner's inner surface radius. With perfect flux conservation, Bz and dBz/dt values exceeding 104 T and 1012 T/s, respectively, are expected. These large values, the diminishing liner volume, and the harsh environment on Z, make it particularly challenging to measure these fields. We report our latest efforts to do so using three primary techniques: (1) micro B-dot probes, (2) streaked visible Zeeman spectroscopy, and (3) fiber-based Faraday rotation. We will also briefly highlight some recent developments using neutron diagnostics (ratio of secondary DT to primary DD neutrons and secondary DT neutron energy spectra) to assess the degree of magnetization in fully integrated magnetized liner inertial fusion (MagLIF) experiments on Z. This project was funded in part by Sandia's LDRD program and US DOE-NNSA Contract DE-AC04-94AL85000.

  10. Results from colliding magnetized plasma jet experiments executed at the Trident laser facility

    Science.gov (United States)

    Manuel, M. J.-E.; Rasmus, A. M.; Kurnaz, C. C.; Klein, S. R.; Davis, J. S.; Drake, R. P.; Montgomery, D. S.; Hsu, S. C.; Adams, C. S.; Pollock, B. B.

    2015-11-01

    The interaction of high-velocity plasma flows in a background magnetic field has applications in pulsed-power and fusion schemes, as well as astrophysical environments, such as accretion systems and stellar mass ejections into the magnetosphere. Experiments recently executed at the Trident Laser Facility at the Los Alamos National Laboratory investigated the effects of an expanding aluminum plasma flow into a uniform 4.5-Tesla magnetic field created using a solenoid designed and manufactured at the University of Michigan. Opposing-target experiments demonstrate interesting collisional behavior between the two magnetized flows. Preliminary interferometry and Faraday rotation measurements will be presented and discussed. This work is funded by the U.S Department of Energy, through the NNSA-DS and SC-OFES Joint Program in High-Energy-Density Laboratory Plasmas, grant number DE-NA0001840. Support for this work was provided by NASA through Einstein Postdoctoral Fellowship grant number PF3-140111 awarded by the Chandra X-ray Center, which is operated by the Astrophysical Observatory for NASA under contract NAS8-03060.

  11. Hard diffraction and rapidity gaps

    Energy Technology Data Exchange (ETDEWEB)

    Albrow, M.G.

    1994-08-01

    I describe the evolution of experiments at hadron colliders on (a) high mass diffraction (b) double pomeron exchange, from the ISR through the Sp{bar p}S to the Tevatron. I emphasize an experimental approach to the question: ``What is the pomeron?``

  12. The high-field magnet endstation for X-ray magnetic dichroism experiments at ESRF soft X-ray beamline ID32

    Science.gov (United States)

    Kummer, K.; Fondacaro, A.; Jimenez, E.; Velez-Fort, E.; Amorese, A.; Aspbury, M.; Yakhou-Harris, F.; van der Linden, P.; Brookes, N. B.

    2016-01-01

    A new high-field magnet endstation for X-ray magnetic dichroism experiments has been installed and commissioned at the ESRF soft X-ray beamline ID32. The magnet consists of two split-pairs of superconducting coils which can generate up to 9 T along the beam and up to 4 T orthogonal to the beam. It is connected to a cluster of ultra-high-vacuum chambers that offer a comprehensive set of surface preparation and characterization techniques. The endstation and the beam properties have been designed to provide optimum experimental conditions for X-ray magnetic linear and circular dichroism experiments in the soft X-ray range between 400 and 1600 eV photon energy. User operation started in November 2014. PMID:26917134

  13. X-Ray Diffraction.

    Science.gov (United States)

    Smith, D. K.; Smith, K. L.

    1980-01-01

    Reviews applications in research and analytical characterization of compounds and materials in the field of X-ray diffraction, emphasizing new developments in applications and instrumentation in both single crystal and powder diffraction. Cites 414 references. (CS)

  14. X-Ray Diffraction.

    Science.gov (United States)

    Smith, D. K.; Smith, K. L.

    1980-01-01

    Reviews applications in research and analytical characterization of compounds and materials in the field of X-ray diffraction, emphasizing new developments in applications and instrumentation in both single crystal and powder diffraction. Cites 414 references. (CS)

  15. X-ray speckle experiments on the persistence and disintegration of magnetic memory

    Science.gov (United States)

    Pierce, Michael Scott

    Beautiful theories based on random microscopic disorder have been developed over the past ten years. My goal was to directly compare these theories with precise experiments. To do so, I first developed and then applied coherent x-ray speckle metrology to a series of thin multilayer perpendicular magnetic materials. To directly observe the effects of disorder, increasing degrees of disorder was deliberately introduced into a series of magnetic films. I used coherent x-rays, produced at the Advanced Light Source at Lawrence Berkeley National Laboratory, to generate highly speckled magnetic scattering patterns. The scattering patterns provided both the ensemble average characteristics of the magnetic domains, but were also directly sensitive to the microscopic magnetic domains. The apparently "random" arrangement of the speckles is due to the exact configuration of the magnetic domains in the sample. In effect, each speckle pattern acts as a unique fingerprint for the magnetic domain configuration. Small changes in the domain structure change the speckles, and comparison of the different speckle patterns provides a quantitative determination of how much the domain structure has changed. My experiments quickly answered one longstanding question: How is the magnetic domain configuration at one point on the major hysteresis loop related to the configurations at the same point on the loop during subsequent cycles? This is called microscopic return point memory (RPM). I found the RPM is partial and imperfect in the disordered samples, and completely absent when the disorder was not present. I also introduced and answered a second important, new question: How are the magnetic domains at one point on the major hysteresis loop related to the domains at the complementary point, the inversion symmetric point on the loop, during the same and during subsequent cycles? This is called microscopic complementary point memory (CPM). I found the CPM is also partial and imperfect in the

  16. Neutron diffraction study of the magnetic structures of PrMn2-xCoxGe2 (x = 0.4, 0.5 and 0.8) with a new refinement procedure

    Science.gov (United States)

    Dincer, I.; Elmali, A.; Elerman, Y.; Ehrenberg, H.; Fuess, H.; Isnard, O.

    2004-03-01

    The magnetic structures of PrMn2-xCoxGe2 (x = 0.4, 0.5 and 0.8) with ThCr2Si2-type structure have been investigated by means of neutron diffraction measurements between 2 and 312 K. We introduced a new refinement procedure to determine the magnetic moments of Pr and Mn sublattices below the rare-earth ordering temperature TCPr because of the overlapping of the magnetic reflections of the Pr and Mn sublattices. Rietveld refinements demonstrated that above the Curie temperature an intralayer antiferromagnetic ordering within (001) Mn layers is observed in PrMn1.6Co0.4Ge2 and PrMn1.5Co0.5Ge2, while the intralayer antiferromagnetic ordering within (001) Mn layers is found over the whole temperature range for PrMn1.2Co0.8Ge2. Below the Curie temperature the PrMn1.6Co0.4Ge2 and PrMn1.5Co0.5Ge2 compounds have a canted ferromagnetic structure with the canting angles 62° and 65° at 2 K, respectively. Below 75 and 70 K, a ferromagnetic ordering of the Pr sublattice is observed along the c-axis for these compounds. Below 70 K, a ferromagnetic ordering of Pr sublattices is found (not detected by magnetic measurements) along the c-axis in PrMn1.2Co0.8Ge2.

  17. Neutron diffraction study of the magnetic structures of PrMn{sub 2-x}Co{sub x}Ge{sub 2} (x = 0.4, 0.5 and 0.8) with a new refinement procedure

    Energy Technology Data Exchange (ETDEWEB)

    Dincer, I [Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Besevler-Ankara (Turkey); Elmali, A [Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Besevler-Ankara (Turkey); Elerman, Y [Department of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Besevler-Ankara (Turkey); Ehrenberg, H [Institute for Materials Science, Darmstadt University of Technology, Petersenstrasse 23, D-64287 Darmstadt (Germany); Fuess, H [Institute for Materials Science, Darmstadt University of Technology, Petersenstrasse 23, D-64287 Darmstadt (Germany); Isnard, O [Laboratoire de Cristallographie, CNRS-UJF, BP 166, 38042 Grenoble Cedex 9 (France)

    2004-03-31

    The magnetic structures of PrMn{sub 2-x}Co{sub x}Ge{sub 2} (x = 0.4, 0.5 and 0.8) with ThCr{sub 2}Si{sub 2}-type structure have been investigated by means of neutron diffraction measurements between 2 and 312 K. We introduced a new refinement procedure to determine the magnetic moments of Pr and Mn sublattices below the rare-earth ordering temperature T{sub C}{sup Pr} because of the overlapping of the magnetic reflections of the Pr and Mn sublattices. Rietveld refinements demonstrated that above the Curie temperature an intralayer antiferromagnetic ordering within (001) Mn layers is observed in PrMn{sub 1.6}Co{sub 0.4}Ge{sub 2} and PrMn{sub 1.5}Co{sub 0.5}Ge{sub 2}, while the intralayer antiferromagnetic ordering within (001) Mn layers is found over the whole temperature range for PrMn{sub 1.2}Co{sub 0.8}Ge{sub 2}. Below the Curie temperature the PrMn{sub 1.6}Co{sub 0.4}Ge{sub 2} and PrMn{sub 1.5}Co{sub 0.5}Ge{sub 2} compounds have a canted ferromagnetic structure with the canting angles 62{sup 0} and 65{sup 0} at 2 K, respectively. Below 75 and 70 K, a ferromagnetic ordering of the Pr sublattice is observed along the c-axis for these compounds. Below 70 K, a ferromagnetic ordering of Pr sublattices is found (not detected by magnetic measurements) along the c-axis in PrMn{sub 1.2}Co{sub 0.8}Ge{sub 2}.

  18. Engineering status of the superconducting end cap toroid magnets for the ATLAS experiment at LHC

    CERN Document Server

    Baynham, D Elwyn; Carr, F S; Courthold, M J D; Cragg, D A; Densham, C J; Evans, D; Holtom, E; Rochford, J; Sole, D; Towndrow, Edwin F; Warner, G P

    2000-01-01

    The ATLAS experiment at LHC, CERN will utilise a large, superconducting, air-cored toroid magnet system for precision muon measurements. The magnet system will consist of a long barrel and two end-cap toroids. Each end-cap toroid will contain eight racetrack coils mounted as a single cold mass in cryostat vessel of ~10 m diameter. The project has now moved from the design/specification stage into the fabrication phase. This paper presents the engineering status of the cold masses and vacuum vessels that are under fabrication in industry. Final designs of cold mass supports, cryogenic systems and control/protection systems are presented. Planning for toroid integration, test and installation is described. (3 refs).

  19. Calibration of High Precision Robot Arm for the Crafting of Magnets for Use in Neutron Experiments

    Science.gov (United States)

    Riley, Benjamin; Crawford, Christopher

    2017-01-01

    The magnetic scalar potential can be used to design precision magnetic fields with surface currents in arbitrary geometry. We are using this technique to design holding field coils for spin transport of neutrons and 3He atoms into the measurement cell of the SNS EDM experiment. We construct holding field coils as three-dimensional printed circuits boards using a Staubli RX130 6-axis industrial robotic arm to etch the circuit. While the arm has a 35-micron repeatability position, the absolute accuracy depends on calibration of transformation matrices between each link, characterized by Denavit-Hartenberg parameters. After factors such as coordinate system degeneracies and free parameters are taken into account, there are 29 parameters that must be calibrated. The robot model, calibration method, and results are presented in this poster.

  20. Analysis and modelling of the magnetic and plasma profiles during PPCD experiments in RFX

    Science.gov (United States)

    Puiatti, M. E.; Cappello, S.; Lorenzini, R.; Martini, S.; Ortolani, S.; Paccagnella, R.; Sattin, F.; Terranova, D.; Bolzonella, T.; Buffa, A.; Canton, A.; Carraro, L.; Escande, D. F.; Garzotti, L.; Innocente, P.; Marrelli, L.; Martines, E.; Scarin, P.; Spizzo, G.; Valisa, M.; Zanca, P.; Antoni, V.; Apolloni, L.; Bagatin, M.; Baker, W.; Barana, O.; Bettella, D.; Bettini, P.; Cavazzana, R.; Cavinato, M.; Chitarin, G.; Cravotta, A.; D'Angelo, F.; Dal Bello, S.; DeLorenzi, A.; Desideri, D.; Fiorentin, P.; Franz, P.; Frassinetti, L.; Gaio, E.; Giudicotti, L.; Gnesotto, F.; Grando, L.; Guo, S. C.; Luchetta, A.; Malesani, G.; Manduchi, G.; Marchiori, G.; Marcuzzi, D.; Martin, P.; Masiello, A.; Milani, F.; Moresco, M.; Murari, A.; Nielsen, P.; Pasqualotto, R.; Pégourie, B.; Peruzzo, S.; Piovan, R.; Piovesan, P.; Pomaro, N.; Preti, G.; Regnoli, G.; Rostagni, G.; Serianni, G.; Sonato, P.; Spada, E.; Spolaore, M.; Taliercio, C.; Telesca, G.; Toigo, V.; Vianello, N.; Zaccaria, P.; Zaniol, B.; Zanotto, L.; Zilli, E.; Zollino, G.; Zuin, M.

    2003-10-01

    In this paper, we analyse the main features of the pulsed poloidal current drive (PPCD) technique, used in the reversed field pinch configuration to achieve improved confinement conditions. In the RFX experiment, PPCD corresponds to a decrease of the magnetic fluctuations, to a peaking of the temperature profile, and to a reduced transport and plasma-wall interaction. A three-dimensional MHD nonlinear code and one-dimensional time-dependent transport models have been applied to study the effect of PPCD on the magnetic and plasma profiles. The three-dimensional MHD simulations show that the external inductive drive pinches and peaks the current profile driving the configuration through a transient phase, where the spontaneous turbulent dynamo action is quenched. The one-dimensional transport codes indicate that the experimental profile modifications associated with PPCD are consistent with a reduction of the stochastic transport.

  1. Tapping Magnet®'s Culture of Innovation to Improve the Patient Experience.

    Science.gov (United States)

    Rainer, Jennifer

    2017-01-01

    As incentives grow for healthcare organizations to improve the patient experience, an increasing number choose to add consumers directly into their leadership structures. In this final installment about the value of patient and family advisory councils, the senior director of quality at a large, Magnet®-recognized Texas hospital explains how tapping into a well-established Magnet culture helped the organization adopt innovative approaches that produced positive change. Based on an interview with the author, she notes that seeing basic issues through patients' eyes challenged long-held beliefs and led to improvements in a wide variety of areas. A discussion of the next frontier for patient and family advisory councils focuses on the small but growing number of hospitals that bring community members to the table to openly share, dissect, and improve issues of quality and safety.

  2. Setup of a separator magnet and an RFQ-buncher for the TRIGA-SPEC experiment

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, T.; Blaum, K. [Physikalisches Institut, Universitaet Heidelberg (Germany); Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Block, M.; Herfurth, F. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Eberhardt, K. [Institut fuer Kernchemie, Universitaet Mainz (Germany); Eibach, M.; Smorra, C. [Physikalisches Institut, Universitaet Heidelberg (Germany); Institut fuer Kernchemie, Universitaet Mainz (Germany); Ketelaer, J.; Knuth, K. [Institut fuer Physik, Universitaet Mainz (Germany); Lunney, D. [CSNSM, Universite de Paris Sud, Orsay (France); Nagy, S. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Noertershaeuser, W. [Institut fuer Kernchemie, Universitaet Mainz (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany)

    2010-07-01

    Precise experimental data of the ground-state properties of heavy nuclides are required to test the predictive power of nuclear mass models and to support nucleosythesis calculations of the astrophysical r-process. The TRIGA-TRAP mass spectrometer and the TRIGA-LASER laser spectroscopy setup, forming the TRIGA-SPEC experiment, were recently installed at the research reactor TRIGA Mainz in order to perform high-precision measurements of the ground state properties of short-lived neutron-rich radionuclides. The radionuclides are produced by thermal neutron-induced fission in an actinoide target inside the reactor, extracted by a gas-jet system, and ionized by an ECR ion source. The ions of interest will then be mass-separated in a 90 dipole magnet. An RFQ buncher is being installed to accumulate, cool and bunch the ion beam. The status of the implementation of the dipole magnet and the RFQ buncher is presented.

  3. Scoring inflammatory activity of the spine by magnetic resonance imaging in ankylosing spondylitis: a multireader experiment

    DEFF Research Database (Denmark)

    Lukas, Cédric; Braun, Jürgen; van der Heijde, Désirée

    2007-01-01

    OBJECTIVE: Magnetic resonance imaging (MRI) of the spine is increasingly important in the assessment of inflammatory activity in clinical trials with patients with ankylosing spondylitis (AS). We investigated feasibility, inter-reader reliability, sensitivity to change, and discriminatory ability...... the Ankylosing Spondylitis spine Magnetic Resonance Imaging-activity [ASspiMRI-a, grading activity (0-6) per vertebral unit in 23 units]; the Berlin modification of the ASspiMRI-a; and the Spondyloarthritis Research Consortium of Canada (SPARCC) scoring system, which scores the 6 vertebral units considered......) assessed by Z-scores was good and comparable among methods. CONCLUSION: This experiment demonstrates the feasibility of multiple-reader MRI scoring exercises for method comparison, provides evidence for the feasibility, reliability, sensitivity to change, and discriminatory capacity of all 3 tested scoring...

  4. Numerical experiments modeling the buoyancy of bubbles in a vertical plane layer of a magnetic fluid

    Energy Technology Data Exchange (ETDEWEB)

    Tsebers, A.O.

    1985-12-01

    The buoyancy of elliptical bubbles in the absence of surface tension are determined through a numerical experiment as a function of the semiaxis ratio, and the results are found to be in good agreement with the well-known Taylor-Saffman solution. Particular attention is given to the effect of the motion of bubbles on the development of a MHD instability in a transverse magnetic field, and it is shown that this motion stabilizes the development of perturbations in the motion direction and intensifies perturbations in the direction transverse to the motion. It is further shown that in the presence of a magnetic field, the configurations of the buoyant bubbles are not determined uniquely by physical parameters but also depend on their initial profiles. 6 references.

  5. Thrust ripple optimization and experiment for a permanent magnet linear synchronous motor

    Institute of Scientific and Technical Information of China (English)

    XU Yue-tong; FU Jian-zhong; CHEN Zi-chen

    2006-01-01

    Thrust ripple such as end force,slot force and normal force are key factors that affect the properties of permanent magnet linear synchronous motors (PMLSM).According to different mechanics and analytical models,end force resulting from open magnetic circuit of PMLSM was greatly decreased by optimizing the length of the PMLSM mover.Slot force caused by slot effect was greatly reduced by using fraction slot structure,and normal force was calculated through the finite element method (FEM).After thrust ripple was calculated,its uniform formula was obtained through Fourier series nonlinear regression.An experimental system was set up to measure thrust ripple,and experiment results demonstrated that experimental force ripple was quite in line with that calculated by the fitting formula.The optimal theory and analysis method is effective,and the obtained formula can be utilized to compensate thrust ripple in practical applications and improve the motion performance of PMLSM.

  6. Use of movable high-field-strength intraoperative magnetic resonance imaging with awake craniotomies for resection of gliomas: preliminary experience.

    LENUS (Irish Health Repository)

    Leuthardt, Eric C

    2011-07-01

    Awake craniotomy with electrocortical mapping and intraoperative magnetic resonance imaging (iMRI) are established techniques for maximizing tumor resection and preserving function, but there has been little experience combining these methodologies.

  7. Neutron diffraction studies of magnetic ordering in superconducting ErNi{sub 2}B{sub 2}C and TmNi{sub 2}B{sub 2}C in an applied magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Toft, K.N

    2004-01-01

    The field-induced magnetic structures of ErNi{sub 2}B{sub 2}C and TmNi{sub 2}B{sub 2}C in are especially interesting because the field suppresses the superconducting order parameter and therefore the magnetic properties can be studied while varying the strength of superconductivity. ErNi{sub 2}B{sub 2}C: For magnetic fields along all three symmetry directions, the observed magnetic structures have a period corresponding to the Fermi surface nesting structure. The phase diagrams present all the observed magnetic structures. Two results remain unresolved: 1. When applying the magnetic field along [010], the minority domain (Q{sub N}{sup B} = (0,Q,0) with moments perpendicular to the field) shows no signs of hysteresis. I expected it to be a meta-stable state, which would be gradually suppressed by a magnetic field, and when decreasing the field it would not reappear until some small field of approximately 0.1 T. 2. When the field is applied along [110], the magnetic structure rotates a small angle of 0.5 degrees away from the symmetry direction. TmNi{sub 2}B{sub 2}C: A magnetic field applied in the [100] direction suppresses the zero field magnetic structure Q{sub F} = (0.094,0.094,0) (T{sub N} = 1.6 K), in favor of the Fermi surface nesting structure Q{sub N} = (0.483,0,0). The appearance of the Q{sub N} phase was initially believed to be caused by the suppression of superconductivity. This suppression should make it favorable to create a magnetic order with a Q-vector determined by the maximum in the magnetic susceptibility at the Fermi surface nesting vector Q{sub N}. The phase diagram for the magnetic structures is presented, however several properties of the Q{sub N} magnetic structure cannot be explained within any known models. Quadrupolar ordering is suggested as a possible candidate for explaining these features of the Q{sub N} structure. (au)

  8. Robustness via Diffractal Architectures

    CERN Document Server

    Moocarme, Matthew

    2015-01-01

    When plane waves diffract through fractal-patterned apertures, the resulting far-field profiles or diffractals also exhibit iterated, self-similar features. Here we show that this specific architecture enables robust signal processing and spatial multiplexing: arbitrary parts of a diffractal contain sufficient information to recreate the entire original sparse signal.

  9. Predicting Grain Growth in Nanocrystalline Materials: A Thermodynamic and Kinetic-Based Model Informed by High Temperature X-ray Diffraction Experiments

    Science.gov (United States)

    2014-10-01

    Predicting grain growth in nanocrystalline materials requires modeling approaches that incorporate grain boundary thermodynamics and kinetics. In...growth in nanocrystalline materials and this extended model can be applied to understanding how grain size evolves with temperature in other nanocrystalline systems....this work, a thermokinetic model for grain growth was applied to experimental X-ray diffraction measurements from nanocrystalline Fe Zr in an effort 1

  10. Saturn's Magnetic Field Model: Birotor Dipole From Cassini RPWS and MAG Experiments

    Science.gov (United States)

    Galopeau, P. H. M.

    2016-12-01

    The radio and plasma wave science (RPWS) experiment on board the Cassini spacecraft, orbiting around Saturn since July 2004, revealed the presence of two distinct and variable rotation periods in the Saturnian kilometric radiation (SKR) which were attributed to the northern and southern hemispheres respectively. We believe that the periodic time modulations present in the SKR are mainly due to the rotation of Saturn's inner magnetic field. The existence of a double period implies that the inner field is not only limited to a simple rotation dipole but displays more complex structures having the same time periodicities than the radio emission. In order to build a model of this complex magnetic field, it is absolutely necessary to know the accurate phases of rotation linked with the two periods. The radio observations from the RPWS experiment allow a continuous and accurate follow-up of these rotation phases, since the SKR emission is permanently observable and produced very close to the planetary surface. A wavelet transform analysis of the intensity of the SKR signal received at 290 kHz between July 2004 and June 2012 was performed in order to calculate in the same time the different periodicities and phases. A dipole model was proposed for Saturn's inner magnetic field: this dipole presents the particularity to have North and South poles rotating around Saturn's axis at two different angular velocities; this dipole is tilted and not centered. 57 Cassini's revolutions, the periapsis of which is less than 5 Saturnian radii, have been selected for this study. For each of these chosen orbits, it is possible to fit with high precision the measurements of the MAG data experiment given by the magnetometers embarked on board Cassini. A nonrotating external magnetic field completes the model. This study suggests that Saturn's inner magnetic field is neither stationary nor fully axisymmetric. These results can be used as a boundary condition for modelling and constraining

  11. Monolayer to interdigitated partial bilayer smectic C transition in thiophene-based spacer mesogens: X-ray diffraction and (13)C nuclear magnetic resonance studies.

    Science.gov (United States)

    Kesava Reddy, M; Varathan, E; Lobo, Nitin P; Roy, Arun; Narasimhaswamy, T; Ramanathan, K V

    2015-10-06

    Mesophase organization of molecules built with thiophene at the center and linked via flexible spacers to rigid side arm core units and terminal alkoxy chains has been investigated. Thirty homologues realized by varying the span of the spacers as well as the length of the terminal chains have been studied. In addition to the enantiotropic nematic phase observed for all the mesogens, the increase of the spacer as well as the terminal chain lengths resulted in the smectic C phase. The molecular organization in the smectic phase as investigated by temperature dependent X-ray diffraction measurements revealed an interesting behavior that depended on the length of the spacer vis-a-vis the length of the terminal chain. Thus, a tilted interdigitated partial bilayer organization was observed for molecules with a shorter spacer length, while a tilted monolayer arrangement was observed for those with a longer spacer length. High-resolution solid state (13)C NMR studies carried out for representative mesogens indicated a U-shape for all the molecules, indicating that intermolecular interactions and molecular dynamics rather than molecular shape are responsible for the observed behavior. Models for the mesophase organization have been considered and the results understood in terms of segregation of incompatible parts of the mesogens combined with steric frustration leading to the observed lamellar order.

  12. Electromagnetic Emissions During Rock-fracturing Experiments Inside Magnetic Field Free Space

    Science.gov (United States)

    Wang, H.; Zhou, J.; Zhu, T.; Jin, H.

    2012-12-01

    Abnormal electromagnetic emission (EME) signal is one type of the most important precursors before earthquake, which has been widely observed and recorded before large earthquake, but the physical mechanism underlying the phenomenon is unclear and under controversy. Monitoring the EME signals during rock-fracturing experiments in laboratory is an effective way to study the phenomena and their underlying mechanism. Electromagnetic noise is everywhere because industrial and civilian electrical equipments have been widely used, which make difficulties to the in-lab experiments and field monitoring. To avoid the interference from electromagnetic noise, electromagnetic experiments must be carried out inside shielded space. Magnetic Field Free Space (MFFS) was constructed by Institute of Geophysics, China Earthquake Administration in 1980s. MFFS is a near-spherical polyhedron 'space' with 26 faces and inside diameter about 2.3 m. It is enclosed by 8-layer permalloy 1J85 for shielding magnetic field and 2-layer purified aluminium for shielding electric field. MFFS mainly shields static magnetic field by a factor of 160-4000 for the magnetic signals with the frequencies ranging from 0.01 Hz to 10 Hz. The intensity of magnetic field inside the space is less than 20 nT and its fluctuation is less than 0.3 nT in 90 hours. MFFS can dramatically shield EME signals in the frequency range of EME antennas utilized in our experiments, (several to ~320) kHz, by at least 90%, based on observation. Rock specimens (granite, marble) were fractured by two ways inside MFFS. 1) Cuboid bulk specimens were drilled, filled with static cracking agent, and then dilated from inside until fracture. 2) Cylindrical rock specimens were stressed until fracture by using a non-magnetic rock testing machine with the maximum testing force 300kN. EME, acoustic emission (AE) and strain signals were collected synchronously by the same data acquisitor, Acoustic Emission Workstation made by Physical Acoustics

  13. Anvil cell gasket design for high pressure nuclear magnetic resonance experiments beyond 30 GPa.

    Science.gov (United States)

    Meier, Thomas; Haase, Jürgen

    2015-12-01

    Nuclear magnetic resonance (NMR) experiments are reported at up to 30.5 GPa of pressure using radiofrequency (RF) micro-coils with anvil cell designs. These are the highest pressures ever reported with NMR, and are made possible through an improved gasket design based on nano-crystalline powders embedded in epoxy resin. Cubic boron-nitride (c-BN), corundum (α-Al2O3), or diamond based composites have been tested, also in NMR experiments. These composite gaskets lose about 1/2 of their initial height up to 30.5 GPa, allowing for larger sample quantities and preventing damages to the RF micro-coils compared to precipitation hardened CuBe gaskets. It is shown that NMR shift and resolution are less affected by the composite gaskets as compared to the more magnetic CuBe. The sensitivity can be as high as at normal pressure. The new, inexpensive, and simple to engineer gaskets are thus superior for NMR experiments at high pressures.

  14. Anvil cell gasket design for high pressure nuclear magnetic resonance experiments beyond 30 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Meier, Thomas; Haase, Jürgen [Faculty of Physics and Earth Sciences, University of Leipzig, Linnéstrasse 5, Leipzig 04103 (Germany)

    2015-12-15

    Nuclear magnetic resonance (NMR) experiments are reported at up to 30.5 GPa of pressure using radiofrequency (RF) micro-coils with anvil cell designs. These are the highest pressures ever reported with NMR, and are made possible through an improved gasket design based on nano-crystalline powders embedded in epoxy resin. Cubic boron-nitride (c-BN), corundum (α-Al{sub 2}O{sub 3}), or diamond based composites have been tested, also in NMR experiments. These composite gaskets lose about 1/2 of their initial height up to 30.5 GPa, allowing for larger sample quantities and preventing damages to the RF micro-coils compared to precipitation hardened CuBe gaskets. It is shown that NMR shift and resolution are less affected by the composite gaskets as compared to the more magnetic CuBe. The sensitivity can be as high as at normal pressure. The new, inexpensive, and simple to engineer gaskets are thus superior for NMR experiments at high pressures.

  15. Quantum Theory for Large Molecules $C_{60}$ Diffraction

    CERN Document Server

    Wu, Xiang-Yao; Liu, Xiao-Jing; Ba, Nuo; Wu, Yi-Heng; Tang, Hou-Li; Wang, Jing; Zhang, Si-Qi

    2011-01-01

    Diffraction phenomena of large molecules have been studied in many experiments, and these experiments are described by many theoretical works. In this paper, we study $C_{60}$ molecules single and double-slit diffraction with quantum theory approach, and we pay close attention to the $C_{60}$ diffraction experiment carried out by A.Zeilinger et.at in 1999. In double-slit diffraction, we consider the decoherence effect, and find the theoretical results are good agreement with experimental data.

  16. Simulating the magnetized liner inertial fusion plasma confinement with smaller-scale experiments [Simulating the MagLIF plasma confinement with smaller-scale experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ryutov, D. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Cuneo, M. E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Herrmann, M. C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sinars, D. B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Slutz, S. A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2012-06-20

    The recently proposed magnetized liner inertial fusion approach to a Z-pinch driven fusion [Slutz et al., Phys. Plasmas17, 056303 (2010)] is based on the use of an axial magnetic field to provide plasma thermal insulation from the walls of the imploding liner. The characteristic plasma transport regimes in the proposed approach cover parameter domains that have not been studied yet in either magnetic confinement or inertial confinement experiments. In this article, an analysis is presented of the scalability of the key physical processes that determine the plasma confinement. The dimensionless scaling parameters are identified and conclusion is drawn that the plasma behavior in scaled-down experiments can correctly represent the full-scale plasma, provided these parameters are approximately the same in two systems. Furthermore, this observation is important in that smaller-scale experiments typically have better diagnostic access and more experiments per year are possible.

  17. Mean Interplanetary Magnetic Field Measurement Using the ARGO-YBJ Experiment

    CERN Document Server

    Aielli, G; Bartoli, B; Bernardini, P; Bi, X J; Bleve, C; Branchini, P; Budano, A; Bussino, S; Melcarne, A K Calabrese; Camarri, P; Cao, Z; Cappa, A; Cardarelli, R; Catalanotti, S; Cattaneo, C; Celio, P; Chen, S Z; Chen, T L; Chen, Y; Creti, P; Cui, S W; Dai, B Z; Staiti, G D'Alí; Danzengluobu,; Dattoli, M; De Mitri, I; Piazzoli, B D'Ettorre; De Vincenzi, M; Di Girolamo, T; Ding, X H; Di Sciascio, G; Feng, C F; Feng, Z Y; Feng, Zhenyong; Galeazzi, F; Galeotti, P; Gargana, R; Gou, Q B; Guo, Y Q; He, H H; Hu, Haibing; Hu, Hongbo; Huang, Q; Iacovacci, M; Iuppa, R; James, I; Jia, H Y; Labaciren,; Li, H J; Li, J Y; Li, X X; Liberti, B; Liguori, G; Liu, C; Liu, C Q; Liu, M Y; Liu, J; Lu, H; Ma, X H; Mancarella, G; Mari, S M; Marsella, G; Martello, D; Mastroianni, S; Meng, X R; Montini, P; Ning, C C; Pagliaro, A; Panareo, M; Perrone, L; Pistilli, P; Qu, X B; Rossi, E; Ruggieri, F; Saggese, L; Salvini, P; Santonico, R; Shen, P R; Sheng, X D; Shi, F; Stanescu, C; Surdo, A; Tan, Y H; Vallania, P; Vernetto, S; Vigorito, C; Wang, B; Wang, H; Wu, C Y; Wu, H R; Yao, Z G; Xu, B; Xue, L; Yan, Y X; Yang, Q Y; Yang, X C; Yuan, A F; Zha, M; Zhang, H M; Zhang, JiLong; Zhang, JianLi; Zhang, L; Zhang, P; Zhang, X Y; Zhang, Y; Zhaxisangzhu,; Zhaxiciren,; Zhou, X X; Zhu, F R; Zhu, Q Q; Zizzi, G

    2011-01-01

    The sun blocks cosmic ray particles from outside the solar system, forming a detectable shadow in the sky map of cosmic rays detected by the ARGO-YBJ experiment in Tibet. Because the cosmic ray particles are positive charged, the magnetic field between the sun and the earth deflects them from straight trajectories and results in a shift of the shadow from the true location of the sun. Here we show that the shift measures the intensity of the field which is transported by the solar wind from the sun to the earth.

  18. Alpha Magnetic Spectrometer (AMS02) experiment on the International Space Station (ISS)

    Institute of Scientific and Technical Information of China (English)

    Behcet ALPAT

    2003-01-01

    The Alpha Magnetic Spectrometer experiment is realized in two phases. A precursor flight (STS-91)with a reduced experimental configuration (AMS01) has successfully flown on space shuttle Discovery in June 1998.The final version (AMS02) will be installed on the International Space Station (ISS) as an independent module inearly 2006 for an operational period of three years. The main scientific objectives of AMS02 include the searches forthe antimatter and dark matter in cosmic rays. In this work we will discuss the experimental details as well as the im-proved physics capabilities of AMS02 on ISS.

  19. Search for Intermediate Mass Magnetic Monopoles and Nuclearites with the SLIM experiment

    CERN Document Server

    Cecchini, S; Ferdinando, D D; Cozzi, M; Frutti, M; Giacomelli, G; Kumar, A; Manzoor, S; McDonald, J; Medinaceli, E; Nogales, J; Patrizii, L; Pinfold, J L; Popa, V; Qureshi, I E; Saavedra, O; Sher, G; Shahzad, M I; Spurio, M; Ticona, R; Togo, V; Velarde, A

    2005-01-01

    SLIM is a large area experiment (440 m2) installed at the Chacaltaya cosmic ray laboratory since 2001, and about 100 m2 at Koksil, Himalaya, since 2003. It is devoted to the search for intermediate mass magnetic monopoles (107-1013 GeV/c2) and nuclearites in the cosmic radiation using stacks of CR39 and Makrofol nuclear track detectors. In four years of operation it will reach a sensitivity to a flux of about 10-15 cm-2 s-1 sr-1. We present the results of the calibration of CR39 and Makrofol and the analysis of a first sample of the exposed detector.

  20. Study of Lower Hybrid Frequency Turbulence in the Magnetic Reconnection Experiment (MRX)

    Science.gov (United States)

    Dorfman, S. E.; Ji, H.; Roytershteyn, V.; Yamada, M.; Daughton, W. S.; Yoo, J.; Oz, E.; Tharp, T.; Lawrence, E. E.; Myers, C.

    2010-12-01

    One of the key open questions in magnetic reconnection is the nature of the mechanism that governs the reconnection rate in real astrophysical and laboratory systems. Comparisons between fully kinetic 2-D simulations of the Magnetic Reconnection Experiment (MRX) and experimental data indicate that three-dimensional dynamics, such as current layer disruptions recently observed in MRX, may play a key role in resolving an important discrepancy in the reconnection rate and layer width [1,2,3]. These disruptions are often associated with fluctuations in the lower hybrid frequency range and a rapid local reconnection rate. Fluctuations are observed not only in MRX [4], but also in space [5] and 3-D kinetic simulations. Comparison of fluctuation characteristics between the three domains may shed light on the underlying physics. In both the simulation and the experiments, the fluctuations are related to density gradients across the layer. The frequency range is similarly broadband up to the lower hybrid range, and the phase velocities are comparable in appropriately normalized units. However, while the electron drift speed is comparable to the phase velocity at the layer center in the experiment (consistent with previous MRX results [4]), the drift speed in the simulations is considerably larger. Furthermore, the fluctuations observed in the experiment are fully turbulent with correlation lengths the same order as the wavelength while those observed in the simulations and in space are more coherent. Some discharges also display "O-point" signatures consistent with magnetic island like structures. The present research explores the relationship between the disruptions and fluctuations in the context of the reconnection rate problem. Experiments are ongoing to determine what physics is responsible for the broader current layers (and correspondingly smaller drift speeds) observed in the experiment. [1] Y. Ren, et al., Phys. Plasmas 15, 082113 (2008). [2] S. Dorfman, et al

  1. Ultrafast x-ray diffraction of laser-irradiated crystals

    Science.gov (United States)

    Heimann, P. A.; Larsson, J.; Chang, Z.; Lindenberg, A.; Schuck, P. J.; Judd, E.; Padmore, H. A.; Bucksbaum, P. H.; Lee, R. W.; Murnane, M.; Kapteyn, H.; Wark, J. S.; Falcone, R. W.

    1997-07-01

    An apparatus has been developed for measuring time-dependent x-ray diffraction. X-ray pulses from an Advanced Light Source bend magnet are diffracted by a sagittally-focusing Si (111) crystal and then by a sample crystal, presently InSb (111). Laser pulses with 100 fs duration and a repetition rate of 1 KHz irradiate the sample inducing a phase transition. Two types of detectors are being employed: an x-ray streak camera and an avalanche photodiode. The streak camera is driven by a photoconductive switch and has a 2 ps temporal resolution determined by trigger jitter. The avalanche photodiode has high quantum efficiency and sufficient time resolution to detect single x-ray pulses in ALS two bunch or `camshaft' operation. A beamline is under construction dedicated for time resolved and micro-diffraction experiments. In the new beamline a toroidal mirror collects 3 mrad horizontally and makes a 1:1 image of the bend magnet source in the x-ray hutch. A laser induced phase transition has been observed in InSb occurring within 70 ps.

  2. The Development of Multilingual Fraunhofer Single Slit Diffraction Simulation Experiment%多语种夫琅和费单缝衍射仿真实验的开发

    Institute of Scientific and Technical Information of China (English)

    马致明; 阿卜杜热伊木·图尔荪; 木莎·哈山; 阿不都卡得·克力木

    2015-01-01

    以物理模型的数学函数形式为依据,以VB 6.0为开发工具,利用绘图方法和颜色渐变技术开发出了维吾尔语、哈萨克语、汉语多语种夫琅和费单缝衍射仿真实验,用交互式手段动态模拟出该实验中衍射条纹间距和光强随波长和缝距的分布情况,并实现了参数与效果图之间的联动,可为相应内容的教学提供强有力的辅助工具。%Based on the mathematical function of the physical model and VB6.0,the Uruguay,Kazakh,Chinese multilingual Fraunhofer single-slit diffraction simulation experiment has been developed by using the method of drawing and color gradient technology.By means of interactive method,the distribution of the diffraction pattern and the intensity of the diffraction pattern is simulated,and the linkage between the parameters and rendering is implemented in the experiment.It can also provide a powerful auxiliary tool for the teaching of the corresponding content.

  3. Versatile controllability of non-axisymmetric magnetic perturbations in KSTAR experiments

    Energy Technology Data Exchange (ETDEWEB)

    Han, Hyunsun, E-mail: hyunsun@nfri.re.kr; Jeon, Y.M.; Hahn, S.H.; Ahn, H.S.; Bak, J.G.; In, Y.; Kim, J.; Woo, M.H.; Kim, H.S.; Jin, J.K.; Park, B.H.; Yoon, S.W.

    2016-10-15

    Highlights: • A newly upgraded In-Vessel Control Coil(IVCC) system has been installed in KSTAR. • The system consists of broadband power supplies and a current connection patch panel. • The system has been confirmed for various dynamic demands of 3D magnetic field configurations. • It can help expand understanding of the 3D tokamak physics. - Abstract: A newly upgraded IVCC (In-Vessel Control Coil) system equipped with four broadband power supplies, along with a current connection patch panel, are introduced with a discussion of their capabilities on various KSTAR experiments. Until the 2014 KSTAR experimental campaign, the non-axisymmetric field configuration could not be changed in a shot, let alone the limited number of accessible configurations. With the installation of the new power supplies, such restrictions have been greatly reduced. Based on the 2015 KSTAR run-campaign, this new system was confirmed to easily cope with various dynamic demands for toroidal and poloidal phases of the 3D magnetic field in a shot. With newly equipped magnetic sensors, this enables us to extend the operational options and further explore the 3D physics for tokamak plasmas.

  4. Enclosed Chambers for Humidity Control And Sample Containment in Fiber Diffraction

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, M.; Kendall, A.; Tanaka, M.; Weissman, J.S.; Stubbs, G.

    2009-05-26

    A chamber and stretch frame for making fibers for diffraction is described. The chamber is made from a simple plastic cuvette with silicon nitride windows. It is suitable for maintaining constant humidity during fiber drying and data collection, and allows stretching of the fiber and exposure to magnetic fields during sample preparation. If necessary, it provides primary containment for toxic and infectious biological materials. The chamber has been used in fiber diffraction experiments with filamentous plant viruses and a yeast prion protein, and is shown to produce excellent orientation and to maintain hydration and order at the molecular level.

  5. Enclosed chambers for humidity control and sample containment in fiber diffraction

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, M.; Kendall, A.; Tanaka, M.; Weissman, J.S.; Stubbs, G. (Vanderbilt); (HHMI)

    2008-11-03

    A chamber and stretch frame for making fibers for diffraction is described. The chamber is made from a simple plastic cuvette with silicon nitride windows. It is suitable for maintaining constant humidity during fiber drying and data collection, and allows stretching of the fiber and exposure to magnetic fields during sample preparation. If necessary, it provides primary containment for toxic and infectious biological materials. The chamber has been used in fiber diffraction experiments with filamentous plant viruses and a yeast prion protein, and is shown to produce excellent orientation and to maintain hydration and order at the molecular level.

  6. ATLAS results on diffraction and forward physics

    CERN Document Server

    Tasevsky, M; The ATLAS collaboration

    2014-01-01

    Report on activity in the field of diffraction and forward physics in the ATLAS experiment is given. Results from four analyses are discussed, namely based on diffractively enhanced events by vetoing one side of detector, on soft events with rapidity gaps, on events with jet vetoes and on total cross section measurement by the ALFA subdetector.

  7. Hard Diffraction at D{phi}

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Gilvan A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). Lab. de Cosmologia e Fisica Experimental de Altas Energias

    2000-07-01

    Full text follows: We review recent Hard Diffraction results from the D{phi} experiment at Fermilab, for the following processes: hard color singlet exchange, hard single diffraction, and hard double pomeron exchange. Measurements of rates, {eta}, E{sub T} and {radical}S dependencies are presented and comparisons made with predictions of several models. (author)

  8. White-Light Diffraction with a CD

    Science.gov (United States)

    Ivanov, Dragia Trifonov; Nikolaev, Stefan

    2010-01-01

    Various wave optics experiments can be carried out using an ordinary compact disc. The CD is suitable for use as a diffraction grating. For instance, a standard CD (700 MB) has 625 lines/mm. In this article, the authors describe two white-light diffraction demonstrations for a large audience, realizable using a CD (as reflection or transmission…

  9. QCD subgroup on diffractive and forward physics

    Energy Technology Data Exchange (ETDEWEB)

    Albrow, M.G.; Baker, W.; Bhatti, A. [and others

    1996-10-01

    The goal is to understand the pomeron, and hence the behavior of total cross sections, elastic scattering and diffractive excitation, in terms of the underlying theory, QCD. A description of the basic ideas and phenomenology is followed by a discussion of hadron-hadron and electron-proton experiments. An appendix lists recommended diffractive-physics terms and definitions. 44 refs., 6 figs.

  10. Spin flip loss in magnetic confinement of ultracold neutrons for neutron lifetime experiments

    CERN Document Server

    Steyerl, A; Kaufman, C; Müller, G; Malik, S S

    2016-01-01

    We analyze the spin flip loss for ultracold neutrons in magnetic bottles of the type used in experiments aiming at a precise measurement of the neutron lifetime, extending the one-dimensional field model used previously by Steyerl $\\textit{et al.}$ [Phys.Rev.C $\\mathbf{86}$, 065501 (2012)] to two dimensions for cylindrical multipole fields. We also develop a general analysis applicable to three dimensions. Here we apply it to multipole fields and to the bowl-type field configuration used for the Los Alamos UCN$\\tau$ experiment. In all cases considered the spin flip loss calculated exceeds the Majorana estimate by many orders of magnitude but can be suppressed sufficiently by applying a holding field of appropriate magnitude to allow high-precision neutron lifetime measurements, provided other possible sources of systematic error are under control.

  11. Comparison between initial Magnetized Liner Inertial Fusion experiments and integrated simulations

    Science.gov (United States)

    Sefkow, A. B.; Gomez, M. R.; Geissel, M.; Hahn, K. D.; Hansen, S. B.; Harding, E. C.; Peterson, K. J.; Slutz, S. A.; Koning, J. M.; Marinak, M. M.

    2014-10-01

    The Magnetized Liner Inertial Fusion (MagLIF) approach to ICF has obtained thermonuclear fusion yields using the Z facility. Integrated magnetohydrodynamic simulations provided the design for the first neutron-producing experiments using capabilities that presently exist, and the initial experiments measured stagnation radii rstag < 75 μm, temperatures around 3 keV, and isotropic neutron yields up to YnDD = 2 ×1012 from imploded liners reaching peak velocities around 70 km/s over an implosion time of about 60 ns. We present comparisons between the experimental observables and post-shot degraded integrated simulations. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  12. Complex magnetic field exposure system for in vitro experiments at intermediate frequencies.

    Science.gov (United States)

    Lodato, Rossella; Merla, Caterina; Pinto, Rosanna; Mancini, Sergio; Lopresto, Vanni; Lovisolo, Giorgio A

    2013-04-01

    In occupational environments, an increasing number of electromagnetic sources emitting complex magnetic field waveforms in the range of intermediate frequencies is present, requiring an accurate exposure risk assessment with both in vitro and in vivo experiments. In this article, an in vitro exposure system able to generate complex magnetic flux density B-fields, reproducing signals from actual intermediate frequency sources such as magnetic resonance imaging (MRI) scanners, for instance, is developed and validated. The system consists of a magnetic field generation system and an exposure apparatus realized with a couple of square coils. A wide homogeneity (99.9%) volume of 210 × 210 × 110 mm(3) was obtained within the coils, with the possibility of simultaneous exposure of a large number of standard Petri dishes. The system is able to process any numerical input sequence through a filtering technique aimed at compensating the coils' impedance effect. The B-field, measured in proximity to a 1.5 T MRI bore during a typical examination, was excellently reproduced (cross-correlation index of 0.99). Thus, it confirms the ability of the proposed setup to accurately simulate complex waveforms in the intermediate frequency band. Suitable field levels were also attained. Moreover, a dosimetry index based on the weighted-peak method was evaluated considering the induced E-field on a Petri dish exposed to the reproduced complex B-field. The weighted-peak index was equal to 0.028 for the induced E-field, indicating an exposure level compliant with the basic restrictions of the International Commission on Non-Ionizing Radiation Protection. Bioelectromagnetics 34:211-219, 2013. © 2012 Wiley Periodicals, Inc.

  13. Design and experiment of human hand motion driven electromagnetic energy harvester using dual Halbach magnet array

    Science.gov (United States)

    Salauddin, M.; Park, Jae Y.

    2017-03-01

    We present a dual Halbach array electromagnetic energy harvester that generates significant power from hand shaking vibration. The magnetic-spring configuration is employed for generating sufficient power from the hand motion of irregular and low-frequency vibrations. However, significant power generation at low-frequency vibrations is challenging because the power flow decreases as the frequency decreases; moreover, designing a spring-mass system that is suitable for low-frequency-vibration energy harvesting is difficult. In this work, our proposed device overcomes both of these challenges by using a dual Halbach array and magnetic springs. During the experiment, vibration was applied in a horizontal direction to reduce the gravity effect on the Halbach-array structure. To achieve an increased power generation at low-amplitude and low-frequency vibrations, the magnetic structure of the dual Halbach array and the magnetic springs were optimized in terms of the operating frequency and the power density. A prototype was fabricated and tested both using a vibration exciter and by manual hand-shaking. The fabricated device showed resonant behavior during the vibration exciter test. For the vibration exciter test, the prototype device offers a maximum average power of 2.92 mW to a 62 Ω optimum load, at a 6 Hz resonance frequency and under a 0.5 g acceleration. The prototype device is capable of delivering a maximum average power of 2.27 mW from hand shaking. The fabricated device exhibited a normalized power density 0.46 mW cm‑2g‑2 which is very high compared to the current state-of-the-art devices, representing its ability in powering portable and wearable smart devices from extremely low frequency vibration.

  14. Synthesis, ab initio X-ray powder diffraction crystal structure, and magnetic properties of Mn3(OH)2(C6H2O4S)2 metal-organic framework.

    Science.gov (United States)

    Sibille, Romain; Mazet, Thomas; Elkaïm, Erik; Malaman, Bernard; François, Michel

    2013-01-18

    A new hydroxythiophenedicarboxylate metal-organic framework based on Mn(II) cations has been obtained by an aqueous two-step procedure including hydrothermal treatment. The structure of Mn(3)(OH)(2)(C(6)H(2)O(4)S)(2) has been determined ab initio from synchrotron X-ray powder diffraction data and consists of infinite inorganic ribbons which are interlinked by 2,5-thiophenedicarboxylate (tdc) molecules (monoclinic, space group P2(1)/c, a = 3.4473(1) Å, b = 19.1287(1) Å, c = 11.0069(1) Å, β = 97.48(1)°, V = 719.65(1) Å(3), and Z = 2). Each ribbon is built of three vertex-sharing chains of edge-sharing MnO(6) octahedrons. These ribbons are bridged together by the carboxylate functions of the tdc molecule to form a pseudo-2D inorganic subnetwork, while this molecule develops in the third dimension to pillar these pseudo-2D layers. An unprecedented hexadentate symmetric bridging mode is adopted by tdc which bridges two chains of a ribbon on one side and two ribbons of a pseudo-2D inorganic subnetwork on the other side. Magnetic measurements suggest that the titled compound is antiferromagnetic below T(N) = 17.7 K. Heat capacity measurements confirm the existence of a magnetic phase transition toward a 3D long-range ordered state. These C(P)(T) data have also been used for the calculation of the thermal variations of both the adiabatic temperature change ΔT(ad) and magnetic entropy change ΔS(m) of the material, namely its magnetocaloric effect.

  15. Neutron powder diffraction with (nat)Sm: crystal structures and magnetism of a binary samarium deuteride and a ternary samarium magnesium deuteride.

    Science.gov (United States)

    Kohlmann, Holger; Werner, Franz; Yvon, Klaus; Hilscher, Gerfried; Reissner, Michael; Cuello, Gabriel J

    2007-01-01

    Binary SmH(3) (trigonal, a=656.7(3), c=680.1(3) pm, P$\\bar 3$c1, Z=6), ternary SmMg2H7 (tetragonal, a=626.47(6), c=937.2(2) pm, P4(1)2(1)2, Z=4) and the corresponding deuterides SmD3 (a=653.9(1)m, c=676.7(2) pm) and SmMg2D7 (a=624.10(1), c=934.81(2) pm) have been prepared by hydrogenation (deuteration) of elemental samarium and the Laves phase SmMg2, respectively, and investigated by X-ray and neutron powder diffraction and SQUID and vibration magnetometry. The problem of the enormous neutron absorption of the natural isotopic mixture (natSm) is circumvented by carefully choosing the neutron wavelength (approximately 50 pm) and the use of double-walled cylindrical sample holders and a high-intensity neutron diffractometer (D4c at ILL). SmD3 crystallises with a tysonite-type structure and has three independently ordered deuterium atom sites with trigonal-planar, trigonal-pyramidal and tetrahedral metal environments and Sm--D bond lengths in the range 220(1)-258(1) pm (average: 235 pm). SmMg2D7 is a new deuteride that crystallises with an LaMg2D7-type structure. It displays four fully occupied deuterium sites having triangular and tetrahedral metal environments and Sm--D bond lengths in the range 227.6(5)-246.8(8) pm (average: 239 pm). These are the first samarium-deuterium bond lengths to be reported. Both deuterides are paramagnetic down to 2 K (SmD3: mueff=0.63(1) muB, thetap approximately -4 K; SmMg2D7: mueff=0.57(2) muB, thetap approximately -4 K). Their crystal structures and chemical and physical properties suggest mainly ionic bonding according to the limiting ionic formulae Sm3+(H-)3 and Sm3+(Mg2+)2(H-)7.

  16. Three-Axis Magnetic Field Measurements in the TCSU RMF Current Drive Experiment

    Science.gov (United States)

    Velas, K. M.; Milroy, R. D.

    2011-10-01

    A 3-axis probe was installed on TCSU shortly before its shutdown. The probe has 90 windings that simultaneously measure Br, Bθ, and Bz at 30 radial positions and is fully translatable. Positioning the probe at multiple axial positions and taking multiple repeatable shots allows for a full r-z map of the magnetic field. Initially, data has been processed with a 10 kHz low pass filter to capture the steady field. Higher frequency content has more shot-to-shot variability; it is difficult to map this axially. Plans include using a band pass filter to isolate the RMF frequency, which is consistent between shots. It is anticipated that the RMF field, in conjunction with the steady field, will yield a map of the full 3D rotating field structure. The 3- axis probe measurements are used to calculate the end-shorting torque, which opposes the RMF torque. Data from even- and odd-parity experiments will be compared. The NIMROD code has been adapted to simulate the TCSU experiment using boundary conditions adjusted to match both even- and odd-parity experimental conditions. A comparison of the n = 0 components of the calculated fields to the 3- axis probe measurements shows agreement in the magnetic field structure of the FRC as well as in the jet region.

  17. Numerical modeling of laser-driven experiments of colliding jets: Turbulent amplification of seed magnetic fields

    Science.gov (United States)

    Tzeferacos, Petros; Fatenejad, Milad; Flocke, Norbert; Graziani, Carlo; Gregori, Gianluca; Lamb, Donald; Lee, Dongwook; Meinecke, Jena; Scopatz, Anthony; Weide, Klaus

    2014-10-01

    In this study we present high-resolution numerical simulations of laboratory experiments that study the turbulent amplification of magnetic fields generated by laser-driven colliding jets. The radiative magneto-hydrodynamic (MHD) simulations discussed here were performed with the FLASH code and have assisted in the analysis of the experimental results obtained from the Vulcan laser facility. In these experiments, a pair of thin Carbon foils is placed in an Argon-filled chamber and is illuminated to create counter-propagating jets. The jets carry magnetic fields generated by the Biermann battery mechanism and collide to form a highly turbulent region. The interaction is probed using a wealth of diagnostics, including induction coils that are capable of providing the field strength and directionality at a specific point in space. The latter have revealed a significant increase in the field's strength due to turbulent amplification. Our FLASH simulations have allowed us to reproduce the experimental findings and to disentangle the complex processes and dynamics involved in the colliding flows. This work was supported in part at the University of Chicago by DOE NNSA ASC.

  18. Self-generated magnetic fields in direct-drive implosion experiments

    Science.gov (United States)

    Igumenshchev, I. V.; Zylstra, A. B.; Li, C. K.; Nilson, P. M.; Goncharov, V. N.; Petrasso, R. D.

    2014-06-01

    Electric and self-generated magnetic fields in direct-drive implosion experiments on the OMEGA Laser Facility were investigated employing radiography with ˜10- to 60-MeV protons. The experiment used plastic-shell targets with imposed surface defects (glue spots, wires, and mount stalks), which enhance self-generated fields. The fields were measured during the 1-ns laser drive with an on-target intensity ˜1015 W/cm2. Proton radiographs show multiple ring-like structures produced by electric fields ˜107 V/cm and fine structures from surface defects, indicating self-generated fields up to ˜3 MG. These electric and magnetic fields show good agreement with two-dimensional magnetohydrodynamic simulations when the latter include the ∇Te × ∇ne source, Nernst convection, and anisotropic resistivity. The simulations predict that self-generated fields affect heat fluxes in the conduction zone and, through this, affect the growth of local perturbations.

  19. DIRAC detector experiment: the vacuum chamber (blue), beginning of the flat chamber (yellow), magnetic screen (orange) in front of the magnet. The vacuum tube for the primary proton beam is below (sil ver color)

    CERN Multimedia

    Patrice Loïez

    1999-01-01

    DIRAC detector experiment: the vacuum chamber (blue), beginning of the flat chamber (yellow), magnetic screen (orange) in front of the magnet. The vacuum tube for the primary proton beam is below (sil ver color)

  20. Characterization of very young mineral phases of bone by solid state 31phosphorus magic angle sample spinning nuclear magnetic resonance and X-ray diffraction.

    Science.gov (United States)

    Roberts, J E; Bonar, L C; Griffin, R G; Glimcher, M J

    1992-01-01

    The properties of bone mineral change with age and maturation. Several investigators have suggested the presence of an initial or "precursor" calcium phosphate phase to help explain these differences. We have used solid state 31P magic angle sample spinning (MASS) nuclear magnetic resonance (NMR) and X-ray radial distribution function (RDF) analyses to characterize 11- and 17-day-old embryonic chick bone and fractions obtained from them by density fractionation. Density fractionation provides samples of bone containing Ca-P solid-phase deposits even younger and more homogeneous with respect to the age of mineral than the calcium phosphate (Ca-P) deposits in the whole bone samples. The analytical techniques yield no evidence for any distinct phase other than the poorly crystalline hydroxyapatite phase characteristic of mature bone mineral. In particular, there is no detectable crystalline brushite [DCPD, CaHPO4 2H2O less than 1%] or amorphous calcium phosphate (less than 8-10%) in the most recently formed bone mineral. A sizeable portion of the phosphate groups exist as HPO4(2-) in a brushite (DCPD)-like configuration. These acid phosphate moieties are apparently incorporated into the apatitic lattice. The most likely site for the brushite-like configuration is probably on the surface of the crystals.

  1. Acquisition procedures, processing methodologies and preliminary results of magnetic and ROV data collected during the TOMO-ETNA experiment

    Directory of Open Access Journals (Sweden)

    Danilo Cavallaro

    2016-09-01

    Full Text Available The TOMO-ETNA experiment was devised for the investigation of the continental and oceanic crust beneath Mt. Etna volcano and northeastern Sicily up to the Aeolian Islands, through an active source study. In this experiment, a large amount of geophysical data was collected both inland and in the Ionian and Tyrrhenian Seas for identifying the major geological and structural features offshore Mt. Etna and NE Sicily. One of the oceanographic cruises organized within the TOMO-ETNA experiment was carried out on the hydrographic vessel “Galatea” by Italian Navy. During the cruise a detailed magnetic survey and a set of ROV (remotely operated vehicle dives were performed offshore Mt. Etna. The magnetic survey allowed the compilation of a preliminary magnetic map revealing a clear direct relationship between volcanic structures and high frequency magnetic anomalies. Significant positive magnetic anomalies were identified offshore the Timpa area and along the easternmost portion of the Riposto Ridge and correlated to a primitive volcanic edifice and to shallow volcanic bodies, respectively. On the whole, the magnetic anomaly map highlights a clear SW-NE decreasing trend, where high amplitude positive magnetic anomaly pattern of the SW sector passes, northeastwardly, to a main negative one. ROV dives permitted to directly explore the shallowest sectors of the Riposto Ridge and to collect several videos and seafloor samples, allowing us to identify some locally developed volcanic manifestations.

  2. Diffractive stacks of metamaterial lattices with a complex unit cell : Self-consistent long-range bianisotropic interactions in experiment and theory

    NARCIS (Netherlands)

    Kwadrin, A.; Koenderink, A.F.

    2014-01-01

    Metasurfaces and metamaterials promise arbitrary rerouting of light using two-dimensional (2D) planar arrangements of electric and magnetic scatterers, respectively, 3D stacks built out of such 2D planes. An important problem is how to self-consistently model the response of these systems in a

  3. Modern diffraction methods

    CERN Document Server

    Mittemeijer, E J

    2013-01-01

    The role of diffraction methods for the solid-state sciences has been pivotal to determining the (micro)structure of a material. Particularly, the expanding activities in materials science have led to the development of new methods for analysis by diffraction. This book offers an authoritative overview of the new developments in the field of analysis of matter by (in particular X-ray, electron and neutron) diffraction. It is composed of chapters written by leading experts on 'modern diffraction methods'. The focus in the various chapters of this book is on the current forefront of research on

  4. Robustness of Cantor diffractals.

    Science.gov (United States)

    Verma, Rupesh; Sharma, Manoj Kumar; Banerjee, Varsha; Senthilkumaran, Paramasivam

    2013-04-08

    Diffractals are electromagnetic waves diffracted by a fractal aperture. In an earlier paper, we reported an important property of Cantor diffractals, that of redundancy [R. Verma et. al., Opt. Express 20, 8250 (2012)]. In this paper, we report another important property, that of robustness. The question we address is: How much disorder in the Cantor grating can be accommodated by diffractals to continue to yield faithfully its fractal dimension and generator? This answer is of consequence in a number of physical problems involving fractal architecture.

  5. MAGNET

    CERN Multimedia

    by B. Curé

    2011-01-01

    The magnet operation was very satisfactory till the technical stop at the end of the year 2010. The field was ramped down on 5th December 2010, following the successful regeneration test of the turbine filters at full field on 3rd December 2010. This will limit in the future the quantity of magnet cycles, as it is no longer necessary to ramp down the magnet for this type of intervention. This is made possible by the use of the spare liquid Helium volume to cool the magnet while turbines 1 and 2 are stopped, leaving only the third turbine in operation. This obviously requires full availability of the operators to supervise the operation, as it is not automated. The cryogenics was stopped on 6th December 2010 and the magnet was left without cooling until 18th January 2011, when the cryoplant operation resumed. The magnet temperature reached 93 K. The maintenance of the vacuum pumping was done immediately after the magnet stop, when the magnet was still at very low temperature. Only the vacuum pumping of the ma...

  6. Multiaxial magnetic ordering in NdMg

    CERN Document Server

    Deldem, M; Galera, R M; Morin, P; Schmitt, D; Ouladdiaf, B

    1998-01-01

    NdMg is a cubic compound (CsCl-type) which orders antiferromagnetically at T sub N =61 K. The magnetization measurements show a second transition at T sub R =35 K. Over the whole order range, the powder neutron diffraction pattern can be indexed on the hypothesis of a collinear structure, the magnetic moments being parallel to the wave vector. The neutron diffraction experiments on a single crystal, under an applied magnetic field, establish that the transition at T sub R corresponds to a change from a collinear structure to a multiaxial one. The magnetic moments successively point along a fourfold axis, in the collinear structure, and along twofold axes in the multiaxial one. This sequence of magnetic structures is consistent with the coexistence of ferroquadrupolar gamma-couplings and antiferroquadrupolar epsilon-couplings. (author)

  7. Pulsed high-magnetic-field experiments: New insights into the magnetocaloric effect in Ni-Mn-In Heusler alloys

    Science.gov (United States)

    Salazar Mejía, C.; Ghorbani Zavareh, M.; Nayak, A. K.; Skourski, Y.; Wosnitza, J.; Felser, C.; Nicklas, M.

    2015-05-01

    The present pulsed high-magnetic-field study on Ni50Mn35In15 gives an extra insight into the thermodynamics of the martensitic transformation in Heusler shape-memory alloys. The transformation-entropy change, ΔS, was estimated from field-dependent magnetization experiments in pulsed high magnetic fields and by heat-capacity measurements in static fields. We found a decrease of ΔS with decreasing temperature. This behavior can be understood by considering the different signs of the lattice and magnetic contributions to the total entropy. Our results further imply that the magnetocaloric effect will decrease with decreasing temperature and, furthermore, the martensitic transition is not induced anymore by changing the temperature in high magnetic fields.

  8. Pulsed high-magnetic-field experiments: New insights into the magnetocaloric effect in Ni-Mn-In Heusler alloys

    Energy Technology Data Exchange (ETDEWEB)

    Salazar Mejía, C., E-mail: Catalina.Salazar@cpfs.mpg.de; Nayak, A. K.; Felser, C.; Nicklas, M. [Max Planck Institute for Chemical Physics of Solids, 01187 Dresden (Germany); Ghorbani Zavareh, M.; Wosnitza, J. [Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany); Institut für Festkörperphysik, TU Dresden, 01062 Dresden (Germany); Skourski, Y. [Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany)

    2015-05-07

    The present pulsed high-magnetic-field study on Ni{sub 50}Mn{sub 35}In{sub 15} gives an extra insight into the thermodynamics of the martensitic transformation in Heusler shape-memory alloys. The transformation-entropy change, ΔS, was estimated from field-dependent magnetization experiments in pulsed high magnetic fields and by heat-capacity measurements in static fields. We found a decrease of ΔS with decreasing temperature. This behavior can be understood by considering the different signs of the lattice and magnetic contributions to the total entropy. Our results further imply that the magnetocaloric effect will decrease with decreasing temperature and, furthermore, the martensitic transition is not induced anymore by changing the temperature in high magnetic fields.

  9. Accessing interior magnetic field vector components in neutron electric dipole moment experiments via exterior measurements, I. Boundary-value techniques

    CERN Document Server

    Plaster, B

    2013-01-01

    We propose a new concept for determining the interior magnetic field vector components in neutron electric dipole moment experiments. If a closed three-dimensional boundary surface surrounding the fiducial volume of an experiment can be defined such that its interior encloses no currents or sources of magnetization, each of the interior vector field components and the magnetic scalar potential will satisfy a Laplace equation. Therefore, if either the vector field components or the normal derivative of the scalar potential can be measured on the surface of this boundary, thus defining a Dirichlet or Neumann boundary-value problem, respectively, the interior vector field components or the scalar potential (and, thus, the field components via the gradient of the potential) can be uniquely determined via solution of the Laplace equation. We discuss the applicability of this technique to the determination of the interior magnetic field components during the operating phase of neutron electric dipole moment experim...

  10. A finite difference method with periodic boundary conditions for simulations of diffusion-weighted magnetic resonance experiments in tissue.

    Science.gov (United States)

    Russell, Greg; Harkins, Kevin D; Secomb, Timothy W; Galons, Jean-Philippe; Trouard, Theodore P

    2012-02-21

    A new finite difference (FD) method for calculating the time evolution of complex transverse magnetization in diffusion-weighted magnetic resonance imaging and spectroscopy experiments is described that incorporates periodic boundary conditions. The new FD method relaxes restrictions on the allowable time step size employed in modeling which can significantly reduce computation time for simulations of large physical extent and allow for more complex, physiologically relevant, geometries to be simulated.

  11. The BMV experiment : a novel apparatus to study the propagation of light in a transverse magnetic field

    CERN Document Server

    Battesti, Remy; Batut, Sebastien; Robilliard, Cecile; Bailly, Gilles; Michel, Christophe; Nardone, Marc; Pinard, Laurent; Portugall, Oliver; Trenec, Gerard; Mackowski, Jean-Marie; Rikken, Geert L J A; Vigue, Jacques; Rizzo, Carlo

    2007-01-01

    In this paper, we describe in detail the BMV (Bir\\'efringence Magn\\'etique du Vide) experiment, a novel apparatus to study the propagation of light in a transverse magnetic field. It is based on a very high finesse Fabry-Perot cavity and on pulsed magnets specially designed for this purpose. We justify our technical choices and we present the current status and perspectives.

  12. Generalising spin-ice: the magnetic ground-state of gadolinium titanate

    Science.gov (United States)

    Brammall, M. I.; Briffa, A. K. R.; Long, M. W.

    2011-03-01

    We investigate the complex low-temperature magnetic ordering of the antiferro-magnetic pyrochlore Gd2Ti2O7. Mössbauer experiments indicate that the spins have equal-magnitude magnetic moments, which are restricted to lie in planes perpendicular to the local crystallographic directions. In addition neutron diffraction experiments show a magnetic scattering vector of (1/2,1/2,1/2) which is consistent with thirty-two atoms per magnetic unit cell. These restrictions are compatible with only two distinct magnetically ordered states.

  13. Surprises in aperiodic diffraction

    CERN Document Server

    Baake, Michael

    2009-01-01

    Mathematical diffraction theory is concerned with the diffraction image of a given structure and the corresponding inverse problem of structure determination. In recent years, the understanding of systems with continuous and mixed spectra has improved considerably. Moreover, the phenomenon of homometry shows various unexpected new facets. Here, we report on some of the recent results in an exemplary and informal fashion.

  14. Hard X-Ray Burst Detected From Caltech Plasma Jet Experiment Magnetic Reconnection Event

    Science.gov (United States)

    Marshall, Ryan S.; Bellan, Paul M.

    2016-10-01

    In the Caltech plasma jet experiment a 100 kA MHD driven jet becomes kink unstable leading to a Rayleigh-Taylor instability that quickly causes a magnetic reconnection event. Movies show that the Rayleigh-Taylor instability is simultaneous with voltage spikes across the electrodes that provide the current that drives the jet. Hard x-rays between 4 keV and 9 keV have now been observed using an x-ray scintillator detector mounted just outside of a kapton window on the vacuum chamber. Preliminary results indicate that the timing of the x-ray burst coincides with a voltage spike on the electrodes occurring in association with the Rayleigh-Taylor event. The x-ray signal accompanies the voltage spike and Rayleigh-Taylor event in approximately 50% of the shots. A possible explanation for why the x-ray signal is sometimes missing is that the magnetic reconnection event may be localized to a specific region of the plasma outside the line of sight of the scintillator. The x-ray signal has also been seen accompanying the voltage spike when no Rayleigh-Taylor is observed. This may be due to the interframe timing on the camera being longer than the very short duration of the Rayleigh-Taylor instability.

  15. On magnetization of quark-gluon plasma at the LHC experiment energies

    CERN Document Server

    Skalozub, V

    2016-01-01

    Large scale chromomagnetic, B_3, B_8, and usual magnetic,H, fields have to be generated in QCD after the deconfinement phase transition (DPT) at temperatures T larger than deconfinement temperature T_d. The two former fields are created spontaneously due to asymptotic freedom of gluon intaractions. Whereas H is produced due to either the feature of quarks to possess both electric and color charges or a vacuum polarization in this case. At the polarization, the vacuum quark loops mix the external fields. As a result, B_3, B_8 become the sources generating H. The latter field appears at $T$ much lower than the electroweak phase transition temperature T_ew. This mechanism should exhibit itself at the LHC experiments on heavy ion collisions. It operates at the one-loop diagram level for an effective potential. The created fields are temperature dependent and occupying the macroscopic volume of quark-gluon plasma. The magnetization influences different processes and may serve as a signal for the DPT.

  16. Baby MIND: a magnetized segmented neutrino detector for the WAGASCI experiment

    Science.gov (United States)

    Antonova, M.; Asfandiyarov, R.; Bayes, R.; Benoit, P.; Blondel, A.; Bogomilov, M.; Bross, A.; Cadoux, F.; Cervera, A.; Chikuma, N.; Dudarev, A.; Ekelöf, T.; Favre, Y.; Fedotov, S.; Hallsjö, S.-P.; Izmaylov, A.; Karadzhov, Y.; Khabibullin, M.; Khotyantsev, A.; Kleymenova, A.; Koga, T.; Kostin, A.; Kudenko, Y.; Likhacheva, V.; Martinez, B.; Matev, R.; Medvedeva, M.; Mefodiev, A.; Minamino, A.; Mineev, O.; Nessi, M.; Nicola, L.; Noah, E.; Ovsiannikova, T.; Pais Da Silva, H.; Parsa, S.; Rayner, M.; Rolando, G.; Shaykhiev, A.; Simion, P.; Soler, F. J. P.; Suvorov, S.; Tsenov, R.; Ten Kate, H.; Vankova-Kirilova, G.; Yershov, N.

    2017-07-01

    T2K (Tokai-to-Kamioka) is a long-baseline neutrino experiment in Japan designed to study various parameters of neutrino oscillations. A near detector complex (ND280) is located 280 m downstream of the production target and measures neutrino beam parameters before any oscillations occur. ND280's measurements are used to predict the number and spectra of neutrinos in the Super-Kamiokande detector at the distance of 295 km. The difference in the target material between the far (water) and near (scintillator, hydrocarbon) detectors leads to the main non-cancelling systematic uncertainty for the oscillation analysis. In order to reduce this uncertainty a new WAter-Grid-And-SCintillator detector (WAGASCI) has been developed. A magnetized iron neutrino detector (Baby MIND) will be used to measure momentum and charge identification of the outgoing muons from charged current interactions. The Baby MIND modules are composed of magnetized iron plates and long plastic scintillator bars read out at the both ends with wavelength shifting fibers and silicon photomultipliers. The front-end electronics board has been developed to perform the readout and digitization of the signals from the scintillator bars. Detector elements were tested with cosmic rays and in the PS beam at CERN. The obtained results are presented in this paper.

  17. A Cryogen-free Cryostat for Scientific Experiment in Pulsed High Magnetic Fields

    Science.gov (United States)

    Wang, Shaoliang; Li, Liang; Zuo, Huakun; Liu, Mengyu; Peng, Tao

    Traditional cryostats for scientific experiments in pulsed high magnetic fields use liquid helium as the cooling source. To reduce the running cost and to increase the operational efficiency, a cryogen-free cryostat based on a GM cryocooler has been developed for a 60 T pulsed field measurement cell at Wuhan National High Magnetic Field Center. A double layer temperature-control insert was designed to obtain a stable temperature in the sample chamber of the cryostat. In order to eliminate the sample temperature fluctuation caused by the eddy current heating during the pulse, the inner layer is made from a fiberglass tubing with an epoxy coating. Different from the traditional cryostat, the sample and the temperature controller are not immerged in the 4He bath. Instead, they are separated by helium gas under sub-atmospheric pressure, which makes the heat transfer smoother. At the sample position, a resistance heater wound with antiparallel wires is mounted on the inner layer to heat the sample. Using the temperature-control insert, the temperature can be controlled with an accuracy of ±0.01 K in the range of 1.4 K-20 K, and ±0.05 K between 20 K and 300 K.

  18. Field experiment provides ground truth for surface nuclear magnetic resonance measurement

    Science.gov (United States)

    Knight, R.; Grunewald, E.; Irons, T.; Dlubac, K.; Song, Y.; Bachman, H.N.; Grau, B.; Walsh, D.; Abraham, J.D.; Cannia, J.

    2012-01-01

    The need for sustainable management of fresh water resources is one of the great challenges of the 21st century. Since most of the planet's liquid fresh water exists as groundwater, it is essential to develop non-invasive geophysical techniques to characterize groundwater aquifers. A field experiment was conducted in the High Plains Aquifer, central United States, to explore the mechanisms governing the non-invasive Surface NMR (SNMR) technology. We acquired both SNMR data and logging NMR data at a field site, along with lithology information from drill cuttings. This allowed us to directly compare the NMR relaxation parameter measured during logging,T2, to the relaxation parameter T2* measured using the SNMR method. The latter can be affected by inhomogeneity in the magnetic field, thus obscuring the link between the NMR relaxation parameter and the hydraulic conductivity of the geologic material. When the logging T2data were transformed to pseudo-T2* data, by accounting for inhomogeneity in the magnetic field and instrument dead time, we found good agreement with T2* obtained from the SNMR measurement. These results, combined with the additional information about lithology at the site, allowed us to delineate the physical mechanisms governing the SNMR measurement. Such understanding is a critical step in developing SNMR as a reliable geophysical method for the assessment of groundwater resources.

  19. Washer-Gun Plasma Source for Magnetic Reconnection Experiments on VTF

    Science.gov (United States)

    Vrublevskis, A.; Egedal, J.; Fox, W.; Katz, N.; Le, A.; Porkolab, M.

    2009-11-01

    We present a recently built electrostatic washer-gun plasma source for the Versatile Toroidal Facility (VTF). The source produces plasmas with estimated densities of ˜10^19 m^- 3 and electron temperatures of ˜5-20 eV. The present plasma source for VTF is microwave-induced electron cyclotron resonant breakdown and requires a strong toroidal magnetic field, which acts as a guide field in reconnection experiments. The gun will allow reconnection experiments with no guide field. The source is based on the design developed by Sterling Scientific [1, 2]. To operate, gas is injected into a channel formed by a stack of alternating molybdenum and boron nitride washers with a molybdenum electrode washer at each end. A capacitor bank is discharged through these electrodes and the gas. The resulting plasma escapes the channel into the main chamber of the experiment. If available, we will present data on argon plasma produced by the gun inside the VTF. [1ex] [1] G. Fiksel, et al., Plasma Sources Sci. Technol., 5, 78 (1996)[0ex] [2] D. Hartog et al., Plasma Sources Sci. Technol., 6, 492 (1997)

  20. Wide Variety of Experiments Using a Cryogen-Free 27.5 T Hybrid Magnet and a Cryogen-Free 18.1 T Superconducting Magnet

    Science.gov (United States)

    Watanabe, K.; Awaji, S.; Oguro, H.

    2013-03-01

    A cryogen-free hybrid magnet without liquid helium for operation, generating 27.5 T in a 32 mm room temperature bore of an 8 MW water-cooled resistive insert magnet in an 8.5 T background field of a cryogen-free superconducting outsert magnet, is being operated for basic research at low temperatures down to 17 mK in combination with a dilution refrigerator. In addition, we are developing functional materials using a differential thermal analysis DTA at high temperatures up to 1473 K in high fields up to 27 T. This cryogen-free hybrid magnet will be upgraded to generate 29 T by improving the outer superconducting magnet. A cryogen-free 18.1 T superconducting magnet with a 52 mm room temperature experimental bore, consisting of a Bi2Sr2Ca2Cu3O10 (Bi2223) insert coil, has been developed using a GM-JT cryocooler. Recently, bronze-tape-laminated Bi2223 has revealed excellent irreversible stress tolerance of 250 MPa at 77 K. In addition, the critical current properties for recent Bi2223 tapes are largely improved from 200 to 400 A/cm-width at 77 K in a self-field. Therefore, the stainless steel reinforcement tape incorporated for the previous Bi2223 insert coil is no longer needed for a new Bi2223 one. A new Bi2223 insert coil with almost the same size as the existing insert coil can generate two times higher fields at the elevated operation current from 162 to 191 A. An upgraded cryogen-free superconducting magnet can offer a long-term experiment at the constant magnetic field of 20 T for an in-field heat-treatment investigation.