Search Results - (Author, Cooperation:J. B. Hastings)

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  1. 1
    Staff View
    Publication Date:
    2012-08-31
    Publisher:
    Nature Publishing Group (NPG)
    Print ISSN:
    0028-0836
    Electronic ISSN:
    1476-4687
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    http://www.nature.com/

    Latest Papers from Table of Contents or Articles in Press
  2. 2
    Stojanoff, V. ; Hämäläinen, K. ; Siddons, D. P. ; Hastings, J. B. ; Berman, L. E. ; Cramer, S. ; Smith, G.

    [S.l.] : American Institute of Physics (AIP)
    Published 1992
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    A high-resolution fluorescence spectrometer using a Johann geometry in a backscattering arrangement was developed. The spectrometer, with a resolution of 0.3 eV at 6.5 keV, combined with an incident beam, with a resolution of 0.7 eV, form the basis of a high-resolution instrument for measuring x-ray absorption spectra. The advantages of the instrument are illustrated with the near-edge absorption spectrum of dysprosium nitrate.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1143112

    Articles: DFG German National Licenses
  3. 3
    Johnson, Erik D. ; Kao, Chi-Chang ; Hastings, J. B.

    [S.l.] : American Institute of Physics (AIP)
    Published 1992
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    For the study of condensed-matter systems x-ray scattering experiments are often the best choice as they have several desirable features including complete conservation of momentum in the incident and detected particles, well characterized initial and final electronic states, and insensitivity of photon transport to external electric and magnetic fields (as compared to photoelectrons, for example). To extend these techniques to soft x-ray region ((h-dash-bar)ν〈1 keV) the lack of suitable detectors, and the difficulties associated with performing scattering experiments in vacuum must be overcome. In this article we provide details of our instrumental development program, and show some representative examples of experiments we have performed to date.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1143038

    Articles: DFG German National Licenses
  4. 4
    Kao, C.-C. ; Caliebe, W. A. ; Hastings, J. B. ; Hämäläinen, K. ; Krisch, M. H.

    [S.l.] : American Institute of Physics (AIP)
    Published 1996
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    The research program at the inelastic x-ray scattering beamline at the National Synchrotron Light Source is focused on the study of elementary excitations in condensed matter with total energy resolution on the order of 0.1 eV to 1.0 eV. Results from selected experiments are reported to demonstrate the capability of the beamline as well as the information that can be obtained from inelastic x-ray scattering experiments. © 1996 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1147469

    Articles: DFG German National Licenses
  5. 5
    Siddons, D. P. ; Hastings, J. B.

    [S.l.] : American Institute of Physics (AIP)
    Published 1996
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    As the field of nuclear resonant scattering using synchrotron radiation matures, we see a shift from experiments designed to verify theoretical predictions towards those designed to use the phenomenon to elucidate the behavior of a sample. In parallel with this trend towards applications, we have seen further instrumental developments that extend the range of possible applications. This paper will review the recent work in this field with an emphasis on new sources, new isotopes, and new instrumentation. © 1996 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1147349

    Articles: DFG German National Licenses
  6. 6
    Kao, C.-C. ; Hamalainen, K. ; Krisch, M. ; Siddons, D. P. ; Oversluizen, T. ; Hastings, J. B.

    [S.l.] : American Institute of Physics (AIP)
    Published 1995
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    Phase I of the X21 beamline at the National Synchrotron Light Source was commissioned during 1993. The research program at the X21 beamline is focused on the study of electronic excitations in condensed matter with total energy resolution of 0.1–1.0 eV. The source is a 27-pole hybrid wiggler. A water-cooled horizontal focusing Si(220) monochromator and a spherically bent Si(444) analyzer were installed and commissioned. At 8 keV the energy resolution of the monochromator is about 0.7 eV, and the energy resolution of the analyzer is about 0.1 eV. Results from several selected experiments are also discussed. © 1995 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1146467

    Articles: DFG German National Licenses
  7. 7
    Caliebe, W. A. ; Kao, C.-C. ; Berman, L. E. ; Hastings, J. B. ; Krisch, M. H. ; Sette, F. ; Hämäläinen, K.

    [S.l.] : American Institute of Physics (AIP)
    Published 1996
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Spin resolved resonant Raman scattering measurements in Gd metal made by exciting x-ray resonant Raman scattering with circularly polarized x rays near the LIII edge of Gd are presented. The incident photon energy was fixed at the peak of the 2p→4f quadrupolar transition, and the scattered photon was energy analyzed around the 3d→2p fluorescent energy. Asymmetry ratios in the scattered intensity much larger than that of the LIII XMCD effect (x-ray magnetic circular dichroism) were observed upon reversal of the magnetization of the sample or the helicity of the photon. A detailed comparison of these results with XMCD results from both the MIV,V edges and LIII edge of Gd metal will be discussed. © 1996 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.361927

    Articles: DFG German National Licenses
  8. 8
    Kao, C. C. ; Chen, C. T. ; Johnson, E. D. ; Idzerda, Y. U. ; Hastings, J. B.

    [S.l.] : American Institute of Physics (AIP)
    Published 1994
    Staff View
    ISSN:
    1089-7550
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    Recently, there has been a great deal of interest in x-ray magnetic circular dichroism (MCD) and its applications to the study of magnetic thin films and multilayers due to the dramatically enhanced dichroic effect and its element specific nature. In this work, the soft x-ray magneto-optical Kerr effect, an effect closely related to MCD, is investigated. Detailed comparison between MCD and the Kerr effect is discussed. As an example, recent results from a thin bcc Co film will be presented. In the Kerr effect measurement, specular reflectivity as a function of incident angle and photon energy was measured using both linearly polarized and circularly polarized x rays. To give the largest effect, in the case of linearly polarized light, specular reflectivity was measured in the transverse configuration, while in the case of circularly polarized light, the measurement was carried out in the longitudinal configuration. In both cases very large changes in reflectivity, up to 40% in the linearly polarized case and 75% in the circularly polarized case, were observed near the Co LII and LIII absorption edges upon reversal of the direction of the magnetic field. These results agree very well with a macroscopic model calculation.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.355575

    Articles: DFG German National Licenses
  9. 9
    Hämäläinen, K. ; Krisch, M. ; Kao, C.-C. ; Caliebe, W. ; Hastings, J. B.

    [S.l.] : American Institute of Physics (AIP)
    Published 1995
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    The results from a new crystal spectrometer for high-resolution inelastic scattering and resonant Raman scattering spectroscopy are presented. It is based on a cylindrically bent silicon crystal in standard Rowland circle geometry where the energy dispersion is obtained nonconventionally by placing a position sensitive detector perpendicular to the scattering plane. The advantage of this geometry is that the energy dispersion is only about one order of magnitude larger than the intrinsic energy resolution of the instrument, allowing the optimization of the collection efficiency within a narrower energy range of interest while preserving the practical realization of a cylindrically bent crystal. A total energy resolution of 0.7 eV at 8 keV with an energy dispersion of only a few eV was reached. Potential applications of this new geometry as well as comparison with other focusing geometries are also discussed. © 1995 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1145898

    Articles: DFG German National Licenses
  10. 10
    Siddons, D. P. ; Hastings, J. B. ; Faigel, G. ; Grover, J. R. ; Haustein, P. E. ; Berman, L. E.

    [S.l.] : American Institute of Physics (AIP)
    Published 1989
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    Resonant filtration of synchrotron radiation has been proposed as a method of obtaining x rays with extremely narrow bandwidths (or very long coherence lengths). Resonant scattering of x rays and neutrons is of general interest, and displays several phenomena, which require novel instrumentation in order to be properly observed. We describe here some of the techniques which we have developed for the specific purpose of studying dynamical diffraction by the Mössbauer resonance in 57Fe.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1141051

    Articles: DFG German National Licenses
  11. 11
    Hastings, J. B. ; Siddons, D. P. ; Berman, L. E. ; Schneider, J. R.

    [S.l.] : American Institute of Physics (AIP)
    Published 1989
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    A triple-axis spectrometer for high-energy ((approximately-greater-than)150 keV) synchrotron radiation has been constructed and characterized. The reciprocal space resolution function of this instrument has been measured using perfect silicon crystals as monochromator, sample, and analyzer. It was found to have dimensions of 1.0×10−5 A(ring)−1 and 2.3×10−4 A(ring)−1 in the directions perpendicular and parallel to the momentum transfer Q, respectively, comparable to those achievable using standard 8-keV triple-axis instruments. The large penetration depths of high-energy x-ray photons, combined with the high instrumental resolution, opens new possibilities in the study of truly bulk condensed matter systems.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1141060

    Articles: DFG German National Licenses
  12. 12
    Feng, Y. P. ; Sinha, S. K. ; Fullerton, Eric E. ; Grübel, G. ; Abernathy, D. ; Siddons, D. P. ; Hastings, J. B.

    Woodbury, NY : American Institute of Physics (AIP)
    Published 1995
    Staff View
    ISSN:
    1077-3118
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Notes:
    We have observed the Fraunhofer diffraction pattern of x-rays exiting from the end face of a SiO2/polyimide/Si thin-film waveguide. The measured angular intensity distributions are in excellent agreement with those calculated based on the dimensions and the refractive index profile of the guide. Our measurement confirms that, at the end face of the guide, the wavefront of a single guided mode is fully coherent in the direction normal to the guiding plane. This focused and transversely coherent x-ray beam may be used as a source for coherence-based experiments, such as x-ray photon correlation spectroscopy. © 1995 American Institute of Physics.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.115346

    Articles: DFG German National Licenses
  13. 13
    McWhan, D. B. ; Hastings, J. B. ; Kao, C.-C. ; Siddons, D. P.

    [S.l.] : American Institute of Physics (AIP)
    Published 1992
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    The tunability and the polarization of synchrotron radiation open up new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and they fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin-polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1143028

    Articles: DFG German National Licenses
  14. 14
    Berman, Lonny E. ; Hastings, J. B. ; Oversluizen, Tom ; Woodle, Martin

    [S.l.] : American Institute of Physics (AIP)
    Published 1992
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    The X25 beam line at the National Synchrotron Light Source (NSLS) began full-power commissioning in 1990. It extracts radiation from a 27 pole hybrid wiggler, which produces up to 1.8 kW of total power with a peak horizontal density of 450 W/mrad and critical energy of 4.6 keV. The design and performance of the beam line optics are described, in particular, the cooling of the first monochromator crystal.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1142721

    Articles: DFG German National Licenses
  15. 15
    Freund, A. K. ; Marot, G. ; Kawata, H. ; Joksch, St. ; Ziegler, E. ; Berman, L. E. ; Hastings, J. B.

    [S.l.] : American Institute of Physics (AIP)
    Published 1992
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    In this paper x-ray diffraction tests of very thin silicon single crystals exposed to a wiggler beam that can generate a power density up to 200 W/mm2 are reported on. This beam was provided by the beamline X25 at NSLS, where 75 W total power are focused into a spot of 0.8 mm(h)×0.45 mm(v). An 11 μm "thin'' Si foil glued at its periphery onto an aluminum ring at 30 °C was applied to a box that could be pressurized with He. The whole assembly was then mounted on an optically polished and watercooled Be support. By increasing the temperature of the water and thus of the Al ring above 30 °C it was possible to apply a stretching force to the Si membrane in order to keep it flat. Rocking curves 3.3 arcsec wide were obtained with a strongly attenuated beam. The rocking curve width increased to 3.9 arcsec when the power density was increased to 15 W/mm2. The crystal was destroyed at 125 W/mm2 because of the limited thermal conductivity across the small He gap.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1142725

    Articles: DFG German National Licenses
  16. 16
    Freund, A. K. ; Joksch, St. ; Kawata, H. ; Marot, G. ; Ziegler, E. ; Berman, L. E. ; Hastings, J. B.

    [S.l.] : American Institute of Physics (AIP)
    Published 1992
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    High quality beryllium single crystals are currently proposed for several applications in synchrotron radiation x-ray optics, in particular as the first element which will have to take the high power of the beam generated by insertion devices. Be has the advantage that much of this incident radiation is transmitted, especially higher energy wiggler radiation. Therefore, it is important to know how Be crystals behave under high x-ray power. For our test measurements we used the focused wiggler beam of the beam line X25 at the National Synchrotron Light Source, Brookhaven, that provides a power of 75 W at 230 mA ring current and a peak power density in excess of 200 W/mm2. A Be crystal was positioned in this white beam and its reflection properties were studied using a perfect silicon analyzer crystal. An "ideal mosaic'' type rocking curve 58 arcsec wide was obtained with a strongly attenuated beam increasing to 73 arcsec at 200 W/mm2. No deterioration of the crystal was observed. Much better performance is expected for thinner crystals. It can be concluded that presently available Be single crystals have the properties required for currently proposed applications as first optical element.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1142726

    Articles: DFG German National Licenses
  17. 17
    Marot, G. ; Rossat, M. ; Freund, A. ; Joksch, S. ; Kawata, H. ; Zhang, L. ; Ziegler, E. ; Berman, L. ; Chapman, D. ; Hastings, J. B. ; Iarocci, M.

    [S.l.] : American Institute of Physics (AIP)
    Published 1992
    Staff View
    ISSN:
    1089-7623
    Source:
    AIP Digital Archive
    Topics:
    Physics
    Electrical Engineering, Measurement and Control Technology
    Notes:
    In this paper, we report on the design and x-ray diffraction properties of cryocooled silicon single crystals exposed to the following wiggler beams: power density: 150 W/mm2, total power: 75 W and power density: 0.5 W/mm2, total power: 100 W. First, thermomechanical and engineering aspects of low-temperature crystal cooling are discussed, leading to two basic cooling geometries: internal cooling and side cooling. Experimental tests of both these cooling schemes at NSLS on beam lines X25 and X17 are then described and discussed. Finally, engineering problems related to the integration of cryogenic cooling on ESRF beam lines are presented.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1063/1.1142736

    Articles: DFG German National Licenses
  18. 18
    Staff View
    ISSN:
    1572-9540
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Physics
    Notes:
    Abstract In this paper the time dependence of the coherent decay of nuclear excited state in an α-57Fe2O3 single crystal is presented. The experiment was carried out in diffraction geometry. A highly monochromatized and collimated beam of synchrotron radiation was used for the excitation of nuclear levels. Quantum beat spectra taken below and above the (7, 7, 7) pure nucleation reflection of hemative show a characteristic pattern corresponding to the magnetic an quadrupole hyperfine interactions.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF02398354

    Articles: DFG German National Licenses
  19. 19
    Staff View
    ISSN:
    1572-9540
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Physics
    Notes:
    Abstract Fourier analysis of the time evolution of the nuclear Bragg scattering from the (7, 7, 7) reflection in α-hematite (57Fe) excited by synchrotron radiation was used to extract values of Zeeman splitting of the ground and 14.413-keV states of57Fe in the crystal magnetic field. The results so obtained apparently do not agree with the corresponding values obtained from Mössbauer spectroscopy on α-hematite. Possible reasons for the discrepancy are discussed.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF02407660

    Articles: DFG German National Licenses
  20. 20
    Staff View
    ISSN:
    1572-9540
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Physics
    Notes:
    Abstract A program of studies of nuclear Bragg X-ray scattering with57Fe2O3 at the National Synchrotron Light Source at Brookhaven National Laboratory and at the Cornell University CHESS facility is reviewed. Two main areas, instrumentation development and studies of dynamical diffraction processes, are described. The latter area has included: measurements of the temporal behavior of nuclear collective decay mode and direct observation of polarization mixing.
    Type of Medium:
    Electronic Resource
    URL:
    http://dx.doi.org/10.1007/BF02398358

    Articles: DFG German National Licenses