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Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
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1

Introduction to Neutron Spin Echo Spectroscopy  

Science Conference Proceedings (OSTI)

... Nuclear Interaction Neutrons are scattered by the nuclei. Scattering power varies “randomly” from isotope to isotope. ... segment dynamics hydro gels ...

2011-06-22T23:59:59.000Z

2

NSE: the Neutron Spin Echo Spectrometer at SNS | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Spin Echo Spectrometer at SNS Spin Echo Spectrometer at SNS NSE NSE is funded and operated by the Jülich Centre for Neutron Science. The SNS NSE instrument provides ultrahigh resolution spectroscopy with a Fourier time range that covers τ = 1 ps to a nominal 350 ns with a high effective neutron flux, aiming to be the best of its class in both resolution and dynamic range (please refer to the instrument fact sheet for a detailed current status). Researchers use this instrument to investigate soft condensed matter and complex fluids applications in a variety of fields. The planned optional ferromagnetic and intensity-modulated modes will allow for detailed investigation of magnetic samples and phenomena. The design of the NSE spectrometer takes full advantage of recent progress in neutron optics and polarizing supermirror microbenders,1,2 resulting in

3

Electrical detection of spin echoes for phosphorus donors in silicon  

E-Print Network (OSTI)

The electrical detection of spin echoes via echo tomography is used to observe decoherence processes associated with the electrical readout of the spin state of phosphorus donor electrons in silicon near a SiO$_2$ interface. Using the Carr-Purcell pulse sequence, an echo decay with a time constant of $1.7\\pm0.2 \\rm{\\mu s}$ is observed, in good agreement with theoretical modeling of the interaction between donors and paramagnetic interface states. Electrical spin echo tomography thus can be used to study the spin dynamics in realistic spin qubit devices for quantum information processing.

Hans Huebl; Felix Hoehne; Benno Grolik; Andre R. Stegner; Martin Stutzmann; Martin S. Brandt

2007-12-02T23:59:59.000Z

4

THE NCNR NEUTRON SPIN ECHO SPECTROMETER  

Science Conference Proceedings (OSTI)

... The NSE spectrometer, developed in partnership with Exxon Research and Engineering and the Forschungszentrum Jülich in Germany [3], is ...

2000-02-29T23:59:59.000Z

5

Neutron Spin Filters  

Science Conference Proceedings (OSTI)

... many nice scientific results from the use of high intensity polarized neutrons ... Electromagnetic radiation of exactly the right energy can exert a sort of ...

2013-03-12T23:59:59.000Z

6

NCNR Neutron Spin Filters  

Science Conference Proceedings (OSTI)

... be characterized either by the transmission asymmetry A ... defined to be the transmissions for neutrons ... P sub n, (solid thick line), transmission T sub n ...

7

Michael Ohl | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Michael Ohl Lead Instrument Scientist: Neutron Spin Echo Spectrometer (NSE), SNS http:www.jcns.info Education PhD in Physics, University of Augsburg, Germany Description of...

8

Research Highlights | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

by: Agatha Bardoel Melissa Sharp and Michael Ohl at the Neutron Spin Echo Instrument at SNS. Melissa Sharp, NSE instrument scientist, and ORNL biophysicist Alex Johs at the...

9

Neutron single target spin asymmetries in SIDIS  

Science Conference Proceedings (OSTI)

The experiment E06-010 in Hall A at Jefferson Lab took data between November 2008 and February 2009 to directly measure, for the first time, the pion (and kaon) single "neutron" target-spin asymmetry (SSA) in semi-inclusive DIS from a polarized 3He target. Collins, Sivers (and Pretzelosity) neutron asymmetries are going to be extracted from the measured SSA. Details of the experiment are described together with the preliminary results of the ongoing analysis. Near future Hall A experiments on transverse nucleon spin structure are shorty reviewed.

Evaristo Cisbani

2010-04-01T23:59:59.000Z

10

Neutron spin echo spectroscopy and membrane dynamics in ...  

Science Conference Proceedings (OSTI)

... incoherent-quasi-elastic scattering nuclear magnetic resonance etc. ... Page 11. Membrane dynamics – theory for bending - Helfrich bending energy ...

2013-06-17T23:59:59.000Z

11

The objective of a Neutron Spin Echo Experiment is the ...  

Science Conference Proceedings (OSTI)

... mask/unmask that specific phase point by left clicking on ... file in the tree, under the DATA FILES tab. Right-click on the selected object and when the ...

2010-09-02T23:59:59.000Z

12

Kinetics of spin relaxation in quantum wires and channels: Boundary spin echo and formation of a persistent spin helix  

SciTech Connect

In this paper we use a spin kinetic equation to study spin-polarization dynamics in one-dimensional (1D) wires and 2D channels. The spin kinetic equation is valid in both diffusive and ballistic spin transport regimes and therefore is more general than the usual spin drift-diffusion equations. In particular, we demonstrate that in infinite 1D wires with Rashba spin-orbit interaction the exponential spin-relaxation decay can be modulated by an oscillating function. In the case of spin relaxation in finite length 1D wires, it is shown that an initially homogeneous spin polarization spontaneously transforms into a persistent spin helix. We find that a propagating spin-polarization profile reflects from a system boundary and returns back to its initial position similarly to the reflectance of sound waves from an obstacle. The Green's function of the spin kinetic equation is derived for both finite and infinite 1D systems. Moreover, we demonstrate explicitly that the spin relaxation in specifically oriented 2D channels with Rashba and Dresselhaus spin-orbit interactions of equal strength occurs similarly to that in 1D wires of finite length. Finally, a simple transformation mapping 1D spin kinetic equation into the Klein-Gordon equation with an imaginary mass is found thus establishing an interesting connection between semiconductor spintronics and relativistic quantum mechanics.

Slipko, Valeriy A. [Department of Physics and Astronomy and USC Nanocenter, University of South Carolina, Columbia, South Carolina 29208 (United States); Department of Physics and Technology, V. N. Karazin Kharkov National University, Kharkov 61077 (Ukraine); Pershin, Yuriy V. [Department of Physics and Astronomy and USC Nanocenter, University of South Carolina, Columbia, South Carolina 29208 (United States)

2011-10-15T23:59:59.000Z

13

Effect of Secondary Echo Signals in Spin-Systems with a Large Inhomogeneous Broadening of NMR Line  

E-Print Network (OSTI)

The possibility of comparatively simple and fast determination of characteristic relaxation parameters T1, T2 and T3 for nuclear spin-systems with strong Larmor and Rabi inhomogeneous broadenings of NMR lines using the secondary echo signal effect was experimentally shown. Resides, this method gives opportunity to obtain a valuable infomation on the inhomogeneous NMR broadening which reflects the character of magnetic field microscopic destribution in such systems, as example, multidomain magnetics and superconductors.

J. G. Chigvinadze; G. I. Mamniashvili; Yu. G. Sharimanov

2003-10-22T23:59:59.000Z

14

Use of earth field spin echo NMR to search for liquid minerals  

DOE Patents (OSTI)

An instrument for measuring the spatial, qualitative and quantitative parameters of an underground nuclear magnetic resonance (NMR) active liquid mineral deposit, including oil and water. A phased array of excitation and receiver antennas on the surface and/or in a borehole excites the NMR active nuclei in the deposit, and using known techniques from magnetic resonance imaging (MRI), the spatial and quantitative distribution of the deposit can be measured. A surface array may utilize, for example, four large (50-500 diameter) diameter wire loops laid on the ground surface, and a weak (1.5-2.5 kHz) alternating current (AC) field applied, matching the NMR frequency of hydrogen in the rather flat and uniform earth magnetic field. For a short duration (a few seconds) an additional gradient field can be generated, superimposed to the earth field, by applying direct current (DC) to the grid (wire loops), enhancing the position sensitivity of the spin-echo and also suppressing large surface water signals by shifting them to a different frequency. The surface coil excitation can be combined with downhole receivers, which are much more radio-quiet compared to surface receivers, and this combination also enhances the position resolution of the MRI significantly. A downhole receiver module, for example, may have a 5.5 inch diameter and fit in a standard six inch borehole having a one-quarter inch thick stainless steel casing. The receiver module may include more than one receiver units for improved penetration and better position resolution.

Stoeffl, Wolfgang (Livermore, CA)

2001-01-01T23:59:59.000Z

15

Mergers of binary neutron stars with realistic spin  

E-Print Network (OSTI)

Simulations of binary neutron stars have seen great advances in terms of physical detail and numerical quality. However, the spin of the neutron stars, one of the simplest global parameters of binaries, remains mostly unstudied. We present the first, fully nonlinear general relativistic dynamical evolutions of the last three orbits for constraint satisfying initial data of spinning neutron star binaries, with astrophysically realistic spins aligned and anti-aligned to the orbital angular momentum. The initial data is computed with the constant rotational velocity approach. The dynamics of the systems is analyzed in terms of gauge-invariant binding energy vs. orbital angular momentum curves. By comparing to a binary black hole configuration we can estimate the different tidal and spin contributions to the binding energy for the first time. First results on the gravitational wave forms are presented. The phase evolution during the orbital motion is significantly affected by spin-orbit interactions, leading to delayed or early mergers. Furthermore, a frequency shift in the main emission mode of the hyper massive neutron star is observed. Our results suggest that a detailed modeling of merger waveforms requires the inclusion of spin, even for the moderate magnitudes observed in binary neutron star systems.

Sebastiano Bernuzzi; Tim Dietrich; Wolfgang Tichy; Bernd Bruegmann

2013-11-18T23:59:59.000Z

16

News & Events | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Spallation Neutron Source. ORNL said the Spin Echo was installed on Beam Line 15 at the SNS. Eventually, there'll be 25 research instruments of varying types and capabilities,...

17

Measurement of the neutrino-spin correlation parameter B neutron decay using ultracold neutrons  

Science Conference Proceedings (OSTI)

We present a new approach to measuring the neutrino-spin correlation parameter B in neutron decay. The approach combines the technology of large-area ion-implanted silicon detectors being developed for the abBA experiment, with an ultracold neutron source to provide more precise neutron polarimetry. The technique detects both proton and electron from the neutron decay in coincidence. B is determined from an electron-energy-dependent measurement of the proton spin asymmetry. This approach will provide a statistical precision of 1 x 10-4 . The systematic precision is still being evaluated, but is expected to be below 1 x 10-3 , and could approach 1 x 10-4 . A measurement of B with this precision would place constraints on supersymmetric extensions to the Standard Model.

Wilburn, Wesley S [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

18

Precision measurement of the neutron spin dependent structure functions  

Science Conference Proceedings (OSTI)

In experiment E154 at the Stanford Linear Accelerator Center the spin dependent structure function g{sub 1}{sup n} (x, Q{sup 2}) of the neutron was measured by scattering longitudinally polarized 48.3 GeV electrons off a longitudinally polarized {sup 3}He target. The high beam energy allowed the author to extend the kinematic coverage compared to the previous SLAC experiments to 0.014 {le} x {le} 0.7 with an average Q{sup 2} of 5 GeV{sup 2}. The author reports the integral of the spin dependent structure function in the measured range to be {integral}{sub 0.014}{sup 0.7} dx g{sub 1}{sup n}(x, 5 GeV{sup 2}) = {minus}0.036 {+-} 0.004(stat.) {+-} 0.005(syst.). The author observes relatively large values of g{sub 1}{sup n} at low x that call into question the reliability of data extrapolation to x {r_arrow} 0. Such divergent behavior disagrees with predictions of the conventional Regge theory, but is qualitatively explained by perturbative QCD. The author performs a Next-to-Leading Order perturbative QCD analysis of the world data on the nucleon spin dependent structure functions g{sub 1}{sup p} and g{sub 1}{sup n} paying careful attention to the experimental and theoretical uncertainties. Using the parameterizations of the helicity-dependent parton distributions obtained in the analysis, the author evolves the data to Q{sup 2} = 5 GeV{sup 2}, determines the first moments of the polarized structure functions of the proton and neutron, and finds agreement with the Bjorken sum rule.

Kolomensky, Y.G.

1997-02-01T23:59:59.000Z

19

A high-field adiabatic fast passage ultracold neutron spin flipper for the UCNA experiment  

Science Conference Proceedings (OSTI)

The UCNA collaboration is making a precision measurement of the {beta} asymmetry (A) in free neutron decay using polarized ultracold neutrons (UCN). A critical component of this experiment is an adiabatic fast passage neutron spin flipper capable of efficient operation in ambient magnetic fields on the order of 1 T. The requirement that it operate in a high field necessitated the construction of a free neutron spin flipper based, for the first time, on a birdcage resonator. The design, construction, and initial testing of this spin flipper prior to its use in the first measurement of A with UCN during the 2007 run cycle of the Los Alamos Neutron Science Center's 800 MeV proton accelerator is detailed. These studies determined the flipping efficiency of the device, averaged over the UCN spectrum present at the location of the spin flipper, to be {epsilon}=0.9985(4).

Holley, A. T.; Pattie, R. W.; Young, A. R. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States); Broussard, L. J. [Department of Physics, Duke University, Durham, North Carolina 27708 (United States); Davis, J. L.; Ito, T. M.; Lyles, J. T. M.; Makela, M.; Morris, C. L.; Mortensen, R.; Saunders, A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Hickerson, K.; Mendenhall, M. P. [W. K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125 (United States); Liu, C.-Y. [Department of Physics, Indiana University, Bloomington, Indiana 47405 (United States); Mammei, R. R. [Department of Physics, Virginia Tech, Blacksburg, Virginia 24061 (United States); Rios, R. [Department of Physics, Idaho State University, Pocatello, Idaho 83209 (United States)

2012-07-15T23:59:59.000Z

20

Using polarized Neutrons for elastic and dynamic studies on protein systems  

SciTech Connect

We report about measurements at the new Neutron Resonance Spin Echo (NRSE) instrument RESEDA (FRM II, Munich). We have performed polarization analysis, providing information about the fraction of neutrons scattered without and with spin flip at the sample. From comparison with the resolution function measured on a standard sample, the dynamics of the incoherent fraction is detected by NRSE measurements at low temperatures.

Haeussler, W. [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universitaet Muenchen, D-85747 Garching (Germany); Physik-Department E21, Technische Universitaet Muenchen, D-85747 Garching (Germany); Kindervater, J. [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Technische Universitaet Muenchen, D-85747 Garching (Germany)

2010-06-02T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

High-efficiency Resonant rf Spin Rotator with Broad Phase Space Acceptance for Pulsed Polarized Cold Neutron Beams  

SciTech Connect

High precision fundamental neutron physics experiments have been proposed for the intense pulsed spallation neutron beams at JSNS, LANSCE, and SNS to test the standard model and search for new physics. Certain systematic effects in some of these experiments have to be controlled at the few ppb level. The NPD Gamma experiment, a search for the small parity-violating {gamma}-ray asymmetry A{sub Y} in polarized cold neutron capture on parahydrogen, is one example. For the NPD Gamma experiment we developed a radio-frequency resonant spin rotator to reverse the neutron polarization in a 9.5 cm x 9.5 cm pulsed cold neutron beam with high efficiency over a broad cold neutron energy range. The effect of the spin reversal by the rotator on the neutron beam phase space is compared qualitatively to rf neutron spin flippers based on adiabatic fast passage. We discuss the design of the spin rotator and describe two types of transmission-based neutron spin-flip efficiency measurements where the neutron beam was both polarized and analyzed by optically polarized {sup 3}He neutron spin filters. The efficiency of the spin rotator was measured at LANSCE to be 98.8 {+-} 0.5% for neutron energies from 3 to 20 meV over the full phase space of the beam. Systematic effects that the rf spin rotator introduces to the NPD Gamma experiment are considered.

Seo, P. -N. [Los Alamos National Laboratory (LANL); Barron-Palos, L. [Arizona State University; Bowman, J. D. [Los Alamos National Laboratory (LANL); Chupp, T. E. [University of Michigan; Crawford, C. [University of Tennessee, Knoxville (UTK); Dabaghyan, M. [University of New Hampshire; Dawkins, M. [Indiana University; Freedman, S. J. [University of California; Gentile, T. R. [National Institute of Standards and Technology (NIST); Gericke, M. T. [University of Manitoba, Canada; Gillis, R. C. [University of Manitoba, Canada; Greene, G. L. [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Hersman, F. W. [University of New Hampshire; Jones, G. L. [Hamilton College, New York; Kandes, M. [University of Michigan; Lamoreaux, S. [Los Alamos National Laboratory (LANL); Lauss, B. [University of California, Berkeley; Leuschner, M. B. [Indiana University; Mahurin, R. [University of Tennessee, Knoxville (UTK); Mason, M. [University of New Hampshire; Mei, J. [Indiana University; Mitchell, G. S. [Los Alamos National Laboratory (LANL); Nann, H. [Indiana University; Page, S. A. [University of Manitoba, Canada; Penttila, S. I. [Los Alamos National Laboratory (LANL); Ramsay, W. D. [University of Manitoba & TRIUMF, Canada; Salas Bacci, A. [Los Alamos National Laboratory (LANL); Santra, S. [Indiana University; Sharma, M. [University of Michigan; Smith, T. B. [University of Dayton, Ohio; Snow, W. [Indiana University; Wilburn, W. S. [Los Alamos National Laboratory (LANL); Zhu, H. [University of New Hampshire

2008-01-01T23:59:59.000Z

22

Inversion-free, noiseless Raman echoes  

E-Print Network (OSTI)

Using double optical Raman rephasing, an inversion-free resonant Raman echo is studied in an inhomogeneously broadened spin ensemble of a solid medium, where the Raman optical field-excited spin coherence has a frozen propagation vector. Unlike photon echoes whose quantum memory application is strictly limited due to \\pi rephasing pulse-induced population inversion causing quantum noises, the optical Raman field-excited spin echo is inherently silent owing to the frozen propagation vector. Thus, the doubly rephased Raman echo can be directly applied for quantum interface in a population inversion-free environment.

Byoung S. Ham

2011-11-20T23:59:59.000Z

23

Violation of Bell-like Inequality for spin-energy entanglement in neutron polarimetry  

E-Print Network (OSTI)

Violation of a Bell-like inequality for a spin-energy entangled neutron state has been confirmed in a polarimetric experiment. The proposed inequality, in Clauser-Horne-Shimony-Holt (CHSH) formalism, relies on correlations between the spin and energy degree of freedom in a single-neutron system. The entangled states are generated utilizing a suitable combination of two radio-frequency fields in a neutron polarimeter setup. The correlation function S is determined to be 2.333+/-0.005, which violates the Bell-like CHSH inequality by more than 66 standard deviations.

S. Sponar; J. Klepp; C. Zeiner; G. Badurek; Y. Hasegawa

2009-07-27T23:59:59.000Z

24

Black hole remnant of black hole-neutron star coalescing binaries with arbitrary black hole spin  

E-Print Network (OSTI)

A model for determining the dimensionless spin parameter and mass of the black hole remnant of black hole-neutron star mergers with arbitrary initial black hole spin angular momentum, binary mass ratio, and neutron star mass and cold equation of state is formulated. Tests against numerical-relativity results are carried out, showing that both the dimensionless spin parameter and the final mass are accurately reproduced. For the first time, the behaviour of both quantities and of the l = 2, m = 2, n = 0 quasinormal mode frequency is inspected throughout the parameter space. Predictions of this frequency may be exploited to guide gravitational wave modelling and detection efforts, and to extract physical information from detected gravitational wave signals that would help us break degeneracies between binary black hole and black hole-neutron star systems, improve our understanding of compact binary formation, and constrain the neutron star equation of state.

Francesco Pannarale

2013-11-22T23:59:59.000Z

25

Upper bound on parity-violating neutron spin rotation in {sup 4}He  

Science Conference Proceedings (OSTI)

We report an upper bound on parity-violating neutron spin rotation in {sup 4}He. This experiment is the most sensitive search for neutron-weak optical activity yet performed and represents a significant advance in precision in comparison to past measurements in heavy nuclei. The experiment was performed at the NG-6 slow-neutron beamline at the National Institute of Standards and Technology (NIST) Center for Neutron Research. Our result for the neutron spin rotation angle per unit length in {sup 4}He is d{phi}/dz=[+1.7{+-}9.1(stat.){+-}1.4(sys.)]x10{sup -7} rad/m. The statistical uncertainty is smaller than current estimates of the range of possible values of d{phi}/dz in n+{sup 4}He.

Snow, W. M.; Luo, D.; Walbridge, S. B. [Indiana University/CEEM, 2401 Milo B. Sampson Lane, Bloomington, Indiana 47408 (United States); Bass, C. D.; Bass, T. D.; Mumm, H. P.; Nico, J. S. [National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg, Maryland 20899 (United States); Crawford, B. E. [Gettysburg College, 300 North Washington Street, Gettysburg, Pennsylvania 17325 (United States); Gan, K.; Micherdzinska, A. M.; Opper, A. K. [The George Washington University, 725 21st Street NW, Washington, DC 20052 (United States); Heckel, B. R.; Swanson, H. E. [University of Washington/CENPA, Box 354290, Seattle, Washington 98195 (United States); Markoff, D. M. [North Carolina Central University/TUNL, 1801 Fayetteville Street, Durham, North Carolina 27707 (United States); Sarsour, M. [Georgia State University, 29 Peachtree Center Avenue, Atlanta, Georgia 30303-4106 (United States); Sharapov, E. I. [Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna (Russian Federation); Zhumabekova, V. [Al-Farabi Kazakh National University, Al-Farabi Ave. 71, 050038 Almaty (Kazakhstan)

2011-02-15T23:59:59.000Z

26

Precision measurement of neutron spin asymmetry An1 at large xBj using CEBAF at 5.7 GeV.  

E-Print Network (OSTI)

??Nucleon spin structure has remained one of the key issues of hadronic physics since the 1980's. Among the unsolved questions, the neutron spin structure in… (more)

Zheng, Xiaochao, 1977-

2003-01-01T23:59:59.000Z

27

Phase transitions to spin-triplet ferromagnetic superconductivity in neutron stars  

E-Print Network (OSTI)

Effects of the anisotropy of Cooper pairs in spin-triplet ferromagnetic superconductors are investigated on the basis of the Ginzburg-Landau theory. A special attention is paid to the triggering of the superconducting state by the ferromagnetic order. The ground states of these superconductors are outlined and discussed. The idea about a possible coexistence of ferromagnetism and spin-triplet superconductivity in neutron stars is introduced.

Diana V. Shopova; Tsvetomir E. Tsvetkov; Dimo I. Uzunov

2004-10-09T23:59:59.000Z

28

Neutron Interferometry with Polarized Spin States Frank Rioux  

E-Print Network (OSTI)

assistance. #12;U N C O R R EC TED PR O O F A neutron producing target for BINP accelerator-based neutron,Ã? a Budker Institute of Nuclear Physics, Lavreniev ave., 11, Novosibirsk, Russia b All-Russian Research Institute of Technical Physics, Vasiliev str., 13, Snezhinsk, Russia c Novosibirsk State University, Pirogov

Rioux, Frank

29

Spin flip loss in magnetic storage of ultracold neutrons  

E-Print Network (OSTI)

We analyze the depolarization of ultracold neutrons confined in a magnetic field configuration similar to those used in existing or proposed magneto-gravitational storage experiments aiming at a precise measurement of the neutron lifetime. We use an approximate quantum mechanical analysis such as pioneered by Walstrom \\emph{et al} [Nucl. Instrum. Methods Phys. Res. A 599, 82 (2009)]. Our analysis is not restricted to purely vertical modes of neutron motion. The lateral motion is shown to cause the predominant depolarization loss in a magnetic storage trap.

A. Steyerl; C. Kaufman; G. Müller; S. S. Malik; A. M. Desai

2013-07-19T23:59:59.000Z

30

Is there a link between the neutron-star spin and the frequency of the kilohertz quasi-periodic oscillations?  

E-Print Network (OSTI)

There is a general consensus that the frequencies of the kilohertz Quasi-Periodic Oscillations (kHz QPOs) in neutron-star low-mass X-ray binaries are directly linked to the spin of the neutron star. The root of this idea is the apparent clustering of the ratio of the frequency difference of the kHz QPOs and the neutron-star spin frequency, $\\Delta\

Mariano Mendez; Tomaso Belloni

2007-07-31T23:59:59.000Z

31

Neutron Scattering Study of Quantum Phase Transitions inIntegral Spin Chains.  

SciTech Connect

Quite a few low-dimensional magnets are quantum-disordered 'spin liquids' with a characteristic gap in the magnetic excitation spectrum. Among these are antiferromagnetic chains of integer quantum spins. Their generic feature are long-lived massive (gapped) excitations (magnons) that are subject to Zeeman splitting in external magnetic fields. The gap in one of the magnon branches decreases with field, driving a soft-mode quantum phase transition. The system then enters a qualitatively new high-field phase. The actual properties at high fields, particularly the spin dynamics, critically depend on the system under consideration. Recent neutron scattering studies of organometallic polymer crystals NDMAP (Haldane spin chains with anisotropy) and NTENP (dimerized S = 1 chains) revealed rich and unique physics.

Zheludev, Andrey I [ORNL

2006-01-01T23:59:59.000Z

32

Proposed experiment to measure the neutron spin-electron angular correlation in polarized neutron beta decay with ultra-cold neutrons  

SciTech Connect

One area in which the Standard Model can be probed is neutron beta decay. In particular, measurements of angular correlations in neutron beta decay can place constraints on the existence of right-handed currents, the presence of scalar and tensor terms in the weak interaction, and for evidence of Time Reversal Violation, which is expected from the observed violation of CP invariance in kaon decay. A measurement of A, the correlation between the neutron spin and the direction of emission of the electron in neutron decay, can be combined with the neutron lifetime to determine the fundamental vector and axial vector weak coupling constants G{sub A} and G{sub V}. The authors have presented the essential elements of their plans to carry out an A correlation measurement using the UCN source they have constructed at the Manuel Lujan Neutron Scattering Center (MLNSC). Their goal is an initial measurement with an accuracy of about 0.2% of A (which has a value of about {minus}0.114). The count rate expected in the experiment will allow a determination at this statistical accuracy level in a running time of about four months.

Seestrom, S.J.; UCN A Collaboration

1998-12-01T23:59:59.000Z

33

Test of Parity-Conserving Time-Reversal Invariance Using Polarized Neutrons and Nuclear Spin Aligned Holmium  

E-Print Network (OSTI)

A test of parity-conserving, time-reversal non-invariance (PC TRNI) has been performed in 5.9 MeV polarized neutron transmission through nuclear spin aligned holmium. The experiment searches for the T-violating five-fold correlation via a double modulation technique - flipping the neutron spin while rotating the alignment axis of the holmium. Relative cross sections for spin-up and spin-down neutrons are found to be equal to within $1.2 \\times 10^{-5}$ (80\\% confidence). This is a two order of magnitude improvement compared to traditional detailed balance studies of time reversal, and represents the most precise test of PC TRNI in a dynamical process.

P. R. Huffman; N. R. Roberson; W. S. Wilburn; C. R. Gould; D. G. Haase; C. D. Keith; B. W. Raichle; M. L. Seely; J. R. Walston

1996-05-24T23:59:59.000Z

34

Precision measurement of neutron spin asymmetry An1 at large xBj using CEBAF at 5.7 GeV  

E-Print Network (OSTI)

Nucleon spin structure has remained one of the key issues of hadronic physics since the 1980's. Among the unsolved questions, the neutron spin structure in the valence quark region (the large Bjorken variable XBj region) ...

Zheng, Xiaochao, 1977-

2003-01-01T23:59:59.000Z

35

Portable Neutron Sensors for Emergency Response Operations  

SciTech Connect

This article presents the experimental work performed in the area of neutron detector development at the Remote Sensing Laboratory–Andrews Operations (RSL-AO) sponsored by the U.S. Department of Energy, National Nuclear Security Administration (NNSA) in the last four years. During the 1950s neutron detectors were developed mostly to characterize nuclear reactors where the neutron flux is high. Due to the indirect nature of neutron detection via interaction with other particles, neutron counting and neutron energy measurements have never been as precise as gamma-ray counting measurements and gamma-ray spectroscopy. This indirect nature is intrinsic to all neutron measurement endeavors (except perhaps for neutron spin-related experiments, viz. neutron spin-echo measurements where one obtains ?eV energy resolution). In emergency response situations generally the count rates are low, and neutrons may be scattered around in inhomogeneous intervening materials. It is also true that neutron sensors are most efficient for the lowest energy neutrons, so it is not as easy to detect and count energetic neutrons. Most of the emergency response neutron detectors are offshoots of nuclear device diagnostics tools and special nuclear materials characterization equipment, because that is what is available commercially. These instruments mostly are laboratory equipment, and not field-deployable gear suited for mobile teams. Our goal is to design and prototype field-deployable, ruggedized, lightweight, efficient neutron detectors.

,

2012-06-24T23:59:59.000Z

36

Nonlinear Acoustic Echo Suppressor Based on Spectral Correlation between Residual Echo and Echo Replica  

Science Conference Proceedings (OSTI)

This paper proposes a new echo suppressor based on spectral correlation between the residual echo and the echo replica in an ordinary echo canceller. First, it is revealed by experiments that there is a significant correlation between the spectral amplitudes ... Keywords: nonlinear echo, echo canceller, echo suppressor

Osamu Hoshuyama; Akihiko Sugiyama

2006-11-01T23:59:59.000Z

37

High-spin structures of 124-131Te: Competition of proton and neutron pair breakings  

E-Print Network (OSTI)

The 124-131Te nuclei have been produced as fission fragments in two fusion reactions induced by heavy-ions (12C + 238U at 90 MeV bombarding energy and 18O + 208Pb at 85 MeV) and studied with the Euroball array. Their high-spin level schemes have been extended to higher excitation energy from the triple gamma-ray coincidence data. The gamma-gamma angular correlations have been analyzed in order to assign spin and parity values to many observed states. Moreover the half-lives of isomeric states have been measured from the delayed coincidences between the fission-fragment detector SAPhIR and Euroball, as well as from the timing information of the Ge detectors. The behaviors of the yrast structures identified in the present work are first discussed in comparison with the general features known in the mass region, particularly the breakings of neutron pairs occupying the nuh11/2 orbit identified in the neighboring Sn nuclei. The experimental level schemes are then compared to shell-model calculations performed in this work. The analysis of the wave functions shows the effects of the proton-pair breaking along the yrast lines of the heavy Te isotopes.

A. Astier; M. -G. Porquet; Ts. Venkova; Ch. Theisen; G. Duchene; F. Azaiez; G. Barreau; D. Curien; I. Deloncle; O. Dorvaux; B. J. P. Gall; M. Houry; R. Lucas; N. Redon; M. Rousseau; O. Stezowski

2013-12-17T23:59:59.000Z

38

Banks of templates for directed searches of gravitational waves from spinning neutron stars  

Science Conference Proceedings (OSTI)

We construct efficient banks of templates suitable for directed searches of almost monochromatic gravitational waves originating from spinning neutron stars in our Galaxy in data being collected by currently operating interferometric detectors. We thus assume that the position of the gravitational-wave source in the sky is known, but we do not assume that the wave's frequency and its derivatives are a priori known. In the construction we employ a simplified model of the signal with constant amplitude and phase which is a polynomial function of time. All our template banks enable usage of the fast Fourier transform algorithm in the computation of the maximum-likelihood F-statistic for nodes of the grids defining the bank. We study and employ the dependence of the grid's construction on the choice of the position of the observational interval with respect to the origin of time axis. We also study the usage of the fast Fourier transform algorithms with nonstandard frequency resolutions achieved by zero padding or folding the data. In the case of the gravitational-wave signal with one spin-down parameter included we have found grids with covering thicknesses which are only 0.1-16% larger than the thickness of the optimal 2-dimensional hexagonal covering.

Pisarski, Andrzej; Jaranowski, Piotr; Pietka, Maciej [Faculty of Physics, University of Bialystok, Lipowa 41, 15-424 Bialystok (Poland)

2011-02-15T23:59:59.000Z

39

Dr. Georg Ehlers - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Georg Ehlers Georg Ehlers Lead Instrument Scientist: Cold Neutron Chopper Spectrometer (CNCS), SNS Education PhD in Experimental Condensed Matter Physics, the Hahn Meitner Institut, in Berlin, Germany Description of Research Dr. Ehlers joined the Spallation Neutron Source (SNS) in 2003 as the lead instrument scientist for beam line 5, the Cold Neutron Chopper Spectrometer (CNCS). CNCS is a high-resolution, direct geometry, cold neutron, inelastic multi-chopper spectrometer, designed to make use of neutrons with an energy of <50 meV. Before joining the SNS, Dr. Ehlers worked at the Institute Laue-Langevin (ILL), a leading European neutron research facility situated in Grenoble, France for six years. At the ILL, he was instrument-responsible for the spin-echo spectrometers IN11 and IN15, and established a strong research

40

A First Experimental Limit on In-matter Torsion from Neutron Spin Rotation in Liquid He-4  

E-Print Network (OSTI)

We report the first experimental upper bound to our knowledge on possible in-matter torsion interactions of the neutron from a recent search for parity violation in neutron spin rotation in liquid He-4. Our experiment constrains a coefficient $\\zeta$ consisting of a linear combination of parameters involving the time components of the torsion fields $T^\\mu$ and $A^\\mu$ from the nucleons and electrons in helium which violates parity. We report an upper bound of $|\\zeta|physical processes that could be analyzed to constrain in-matter torsion.

Ralf Lehnert; H. Yan; W. M. Snow

2013-11-03T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Investigation of the field-induced ferromagnetic phase transition in spin-polarized neutron matter: A lowest order constrained variational approach  

Science Conference Proceedings (OSTI)

In this article, the lowest order constrained variational method is used to investigate the magnetic properties of spin-polarized neutron matter in the presence of strong magnetic field at zero temperature employing the AV{sub 18} potential. Our results indicate that a ferromagnetic phase transition is induced by a strong magnetic field with strength greater than 10{sup 18} G, leading to a partial spin polarization of the neutron matter. It is also shown that the equation of state of neutron matter in the presence of a magnetic field is stiffer than in the absence of a magnetic field.

Bordbar, G. H. [Department of Physics, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha, P.O. Box 55134-441, Maragha 55177-36698 (Iran, Islamic Republic of); Rezaei, Z.; Montakhab, Afshin [Department of Physics, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of)

2011-04-15T23:59:59.000Z

42

Dzyaloshinsky-Moriya interaction and long life time of the spin state in the Cu$_3$ triangular spin cluster by inelastic neutron scattering measurements  

E-Print Network (OSTI)

Inelastic neutron scattering (INS) experiments have been performed on the Cu$_3$ triangular molecular nanomagnet using powder samples. In the medium resolution INS spectrum measured, there are two peaks at $\\hbar\\omega=0.5$ and 0.6 meV. Comparing the observed $Q$ dependences of these peaks with calculations, these two INS peaks originate from the Cu$_3$ cluster. From the observed peak position, width, and intensity, we have determined the optimum parameters of the spin Hamiltonian consisted of the antiferromagnetic exchange and the Dzyaloshinsky-Moriya interactions, which can also reproduce the magnetic susceptibility measurement. In addition, we have directly observed that the ground state quartet is split into two doublets with the energy separation of 0.103 meV using high-resolution neutron spectroscopy, which exactly corresponds to that expected from the optimum parameters obtained from the medium resolution xperiment. The temperature dependences of the integrated intensities of the 0.5 and 0.6 meV peaks are well reproduced by the Boltzmann distribution of the energy levels of the model Hamiltonian below 10 K. Furthermore, the inelastic peaks were visible even at very high temperatures as 50 K. This indicates extraordinary weak coupling between phonons (or any other perturbations) and spin states in the Cu$_3$ cluster, compared to the other known molecular nanomagnets.

Kazuki Iida; Yiming Qiu; Taku J Sato

2010-05-21T23:59:59.000Z

43

Local and average structures of the spin-glass pyrochlore Y2Mo2O7 from neutron diffraction and neutron pair distribution function analysis  

Science Conference Proceedings (OSTI)

The observation of canonical spin-glass behavior in the pyrochlore oxide Y{sub 2}Mo{sub 2}O{sub 7} has been a subject of considerable interest as the original structural studies were interpreted in terms of a well-ordered crystallographic model. It is widely held that the stabilization of the spin-glass state requires some level of positional disorder along with frustration. Recent reports from local probe measurements, extended x-ray-absorption fine structure (EXAFS) and {sup 89}Y NMR, have been interpreted in terms of disorder involving the Mo-Mo distances (EXAFS) and multiple Y sites (NMR). This work reports results from temperature-dependent (15--300 K) neutron diffraction (ND) and neutron pair distribution function studies which can provide from the same data set information on both the average and local structures. The principal findings are that: (1) there is no crystallographic phase transition over the temperature region studied within the resolution of the ND data; (2) the diffraction data are well fitted using a fully ordered model but with large and anisotropic displacement parameters for three of the four atomic sites; (3) the pairwise real-space correlation function G(r) shows clear evidence that the principal source of disorder is associated with the Y-O1 atom pairs rather than the Mo-Mo pairs, in disagreement with the interpretation of the EXAFS results; (4) fits to the G(r) improve significantly when anisotropic displacements for all sites are included; (5) inclusion of a split-site position parameter for O1 improves, slightly, both the G(r) fits and the Rietveld fits to the ND data; and (6) for all models the fits become worse as the temperature decreases and as the fitting range decreases. These results are qualitatively consistent with the {sup 89}Y NMR observations and perhaps recent muon-spin-relaxation studies. The issue of static versus dynamic disorder is not resolved, definitively. An estimate of the distribution of exchange constants due to the disorder is made using spin-dimer analysis and compared with the Saunders-Chalker model for the generation of spin-glass behavior from 'weak' disorder on geometrically frustrated lattices.

Proffen, Thomas Ernst [Los Alamos National Laboratory; Kim, Hyunjeong [Los Alamos National Laboratory; Greedan, John [MCMASTER UNIV; Gout, Delphine [ORNL; Lozano - Gorrin, A D [MCMASTER UNIV; Derahkshan, Shahab [MCMASTER UNIV; Bozin, E [COLUMBIA UNIV; Billinge, S J L [COLUMBIA UNIV

2009-01-01T23:59:59.000Z

44

Neutrons  

NLE Websites -- All DOE Office Websites (Extended Search)

School on Neutron and X-ray Scattering Oak Ridge 10-24 August 2013 John M. Carpenter ANL, ORNLSNS 18 August 2013 2 Neutron Detection How does one detect a neutron? - It is...

45

SNS Instrument System Beam Lines | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

SNS Instrument Beam Lines SNS Instrument Beam Lines This diagram shows the beam lines designated for currently funded instruments. Clicking on an instrument description will take you to the page for that instrument. Clicking anywhere else on the image will open a full-size, printable PDF file. SNS Instrument Layout Backscattering Spectrometer (BASIS) Disordered Materials Diffractometer (NOMAD) Wide Angular-Range Chopper Spectrometer (ARCS) Fine-Resolution Fermi Chopper Spectrometer (SEQUOIA) Coming Soon - Vibrational Spectrometer (VISION) Neutron Spin Echo (NSE) Hybrid Spectrometer (HYSPEC) Fundamental Neutron Physics Beamline (FNPB) Single Crystal Diffractometer (TOPAZ) Versatile Neutron Imaging Instrument (VENUS) Macromolecular Diffractometer (MaNDi) Powder Diffractometer (POWGEN3) Engineering Diffractometer (VULCAN) Extended Q-Range Small Angle Neutron Diffractometer (EQ-SANS) Cold Neutron Chopper Spectrometer (CNCS) Liquids (horizontal surface) Reflectometer (LR) Magnetic Advanced Grazing InCidence Spectrometer (MAGICS) High Pressure Diffractometer (SNAP) Coming Soon - Elastic Diffuse Scattering Spectrometer (CORELLI)

46

Slow light enhanced photon echoes  

E-Print Network (OSTI)

We report a slow light-enhanced photon echo method, whose retrieval efficiency is two orders of magnitude higher than that of conventional photon echoes. The enhanced photon echo efficiency is due to lengthened interaction time given by ultraslow group velocity.

J. Hahn; B. S. Ham

2009-09-28T23:59:59.000Z

47

Sample Environment Equipment Categories - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Home › Instruments › Sample Environment Home › Instruments › Sample Environment Sample Environment: Categories of Equipment All Ancillary Equipment Auto Changer Closed Cycle Refrigerators Closed Cycle Refrigerators - Bottom Loading Closed Cycle Refrigerators - Top Loading Furnaces Gas Handling Gas Panel High Pressure Systems Liquid Helium Cryostats Magnet Systems Other Special Environments Sample Cell Sample Stick Ultra Low Temperature Devices Sample Environment: by Beam Line All BL-11A-POWGEN BL-11B-MANDI BL-12-TOPAZ BL-13-Fundamental Neutron Physics Beam Line BL-14A-BL-14A BL-14B-HYSPEC BL-15-Neutron Spin Echo (NSE) BL-16B-VISION BL-17-SEQUOIA BL-18-ARCS BL-1A-TOF-USANS BL-1B-NOMAD BL-2-BASIS BL-3-SNAP BL-4A-Magnetism Reflectometer BL-4B-Liquids Reflectometer BL-5-Cold Neutron Chopper Spectrometer (CNCS) BL-6-EQ-SANS

48

{gamma}-ray spectroscopy of neutron-deficient {sup 110}Te. I. Low- and intermediate-spin structures  

SciTech Connect

Excited states have been populated in {sub 52}{sup 110}Te via the {sup 58}Ni({sup 58}Ni,{alpha}2p{gamma}) reaction at 250 MeV. The Gammasphere {gamma}-ray spectrometer was augmented with ancillary detectors for charged-particle and neutron detection in order to provide clean channel selection. The known level scheme of {sup 110}Te has been greatly expanded with the addition of many new structures. Above spin 8{sup +}, negative-parity structures become yrast. The level scheme of {sup 110}Te below 30({Dirac_h}/2{pi}) is discussed in this paper, including possible evidence for octupole correlations inferred from strong B(E1) strengths.

Paul, E. S.; Boston, A. J.; Nolan, P. J.; Semple, A. T. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Chiara, C. J.; Fossan, D. B.; Lane, G. J.; Sears, J. M.; Starosta, K. [Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, New York 11794-3800 (United States); Devlin, M.; LaFosse, D. R.; Sarantites, D. G. [Department of Chemistry, Washington University, St. Louis, Missouri 63130 (United States); Freeman, S. J.; Leddy, M. J. [Schuster Laboratory, University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom); Lee, I. Y.; Macchiavelli, A. O. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Smith, J. F. [Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, New York 11794-3800 (United States); Schuster Laboratory, University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom)

2007-09-15T23:59:59.000Z

49

NIST CENTER FOR NEUTRON RESEARCH LAYOUT  

Science Conference Proceedings (OSTI)

... 17 18 19 13 13 Spin Echo Spectrometer offer- ing neV energy resolution, based upon Jülich design, sponsored by NIST, Jülich, and ExxonMobil. ...

2001-02-27T23:59:59.000Z

50

Dynamics of quantum spin liquid and spin solid phases in IPA-CuCl3 under an applied magnetic field studied with neutron scattering  

SciTech Connect

Inelastic and elastic neutron scattering is used to study spin correlations in the quasi-one-dimensional quantum antiferromagnet IPA-CuCl3 in strong applied magnetic fields. A condensation of magnons and commensurate transverse long-range ordering is observe at a critical field Hc=9.5 T. The field dependencies of the energies and polarizations of all magnon branches are investigated both below and above the transition point. Their dispersion is measured across the entire one-dimensional Brillouin zone in magnetic fields up to 14 T. The critical wave vector of magnon spectrum truncation Masuda et al., Phys. Rev. Lett. 96, 047210 2006 is found to shift from hc0,35 at HHC to hc=0.25 for HHC. A drastic reduction of magnon bandwidths in the ordered phase Garlea et al., Phys. Rev. Lett. 98, 167202 2007 is observed and studied in detail. New features of the spectrum, presumably related to this bandwidth collapse, are observed just above the transition field.

Zheludev, Andrey I [ORNL; Garlea, Vasile O [ORNL; Masuda, T. [Yokohama City University, Japan; Manaka, H. [Kagoshima University, Kagoshima JAPAN; Regnault, L.-P. [CEA, Grenoble, France; Ressouche, E. [CEA, Grenoble, France; Grenier, B. [CEA, Grenoble, France; Chung, J.-H. [National Institute of Standards and Technology (NIST); Qiu, Y. [National Institute of Standards and Technology (NIST); Habicht, Klaus [Hahn-Meitner Institut, Berlin, Germany; Kiefer, K. [Hahn-Meitner Institut, Berlin, Germany; Boehm, Martin [Institut Laue-Langevin (ILL)

2007-01-01T23:59:59.000Z

51

MAGNETIC NEUTRON SCATTERING  

SciTech Connect

Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern science, ranging from large-scale structures and dynamics of polymers and biological systems, to electronic properties of today's technological materials. Neutron scattering developed into a vast field, encompassing many different experimental techniques aimed at exploring different aspects of matter's atomic structure and dynamics. Modern magnetic neutron scattering includes several specialized techniques designed for specific studies and/or particular classes of materials. Among these are magnetic reflectometry aimed at investigating surfaces, interfaces, and multilayers, small-angle scattering for the large-scale structures, such as a vortex lattice in a superconductor, and neutron spin-echo spectroscopy for glasses and polymers. Each of these techniques and many others offer exciting opportunities for examining magnetism and warrant extensive reviews, but the aim of this chapter is not to survey how different neutron-scattering methods are used to examine magnetic properties of different materials. Here, we concentrate on reviewing the basics of the magnetic neutron scattering, and on the recent developments in applying one of the oldest methods, the triple axis spectroscopy, that still is among the most extensively used ones. The developments discussed here are new and have not been coherently reviewed. Chapter 2 of this book reviews magnetic small-angle scattering, and modern techniques of neutron magnetic reflectometry are discussed in Chapter 3.

ZALIZNYAK,I.A.; LEE,S.H.

2004-07-30T23:59:59.000Z

52

TRANSVERSE ECHO MEASUREMENTS IN RHIC.  

SciTech Connect

Diffusion counteracts cooling and the knowledge of diffusion rates is important for the calculation of cooling times and equilibrium beam sizes. Echo measurements are a potentially sensitive method to determine diffusion rates, and longitudinal measurements were done in a number of machines. We report on transverse echo measurements in RHIC and the observed dependence of echo amplitudes on a number of parameters for beams of gold and copper ions, and protons. In particular they examine the echo amplitudes of gold and copper ion bunches of varying intensity, which exhibit different diffusion rates from intrabeam scattering.

FISCHER, W.

2005-09-18T23:59:59.000Z

53

High precision measurements of the neutron spin structure in Hall A at Jlab  

SciTech Connect

Conclusions of this presentation are: (1) JLab energy upgrade will offer new exciting opportunities to study the nucleon (spin) structure such as high precision, unexplored phase space, flavor decomposition; (2) Large technological efforts is in progress to optimally exploit these opportunities; (3) HallA will be the first hall to get the new beam, first experiment expected to run in 2014; (4) A1n likely one of the first experiments to take data in the new 12 GeV era; and (5) SIDIS exp. will follow in couple of years.

Annand, R M; Cates, G; Cisbani, E; Franklin, G B; Liyanage, N; Puckett, A; Rosner, G; Wojtsekhowski, B

2012-04-01T23:59:59.000Z

54

The Science of NSE | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

The Science of the Neutron Spin Echo Spectrometer The Science of the Neutron Spin Echo Spectrometer Main Features NSE is of the original generic IN11 kind, which is the technique with the largest potential to extend the resolution beyond current limits. The instrument possesses a number of unique features: Ultrahigh resolution: τmax ≤ 1 µs (Δħω = 0.7neV) Huge dynamical range extending up to 1:106 Position-sensitive area detector Field compensation and magnetic shielding Optional intensity-modulated mode A moderator detector distance of 18 m yields a frame width of Δλ = 0.366 nm. The resolution of τmax= 1 µs shall be obtained for λ > 1.8 nm (g = 1.8). In addition, due to the TOF λ separation the wavelength dependent part of the Q-resolution is an order of magnitude better than at reactor instruments [3]. Exploiting that the Fourier time τ∼λ3 a subsequent use

55

Level crossings and zero-field splitting in the {Cr8}-cubane spin-cluster studied using inelastic neutron scattering and magnetization  

Science Conference Proceedings (OSTI)

Inelastic neutron scattering (INS) in variable magnetic field and high-field magnetization measurements in the millikelvin temperature range were performed to gain insight into the low-energy magnetic excitation spectrum and the field-induced level crossings in the molecular spin cluster {Cr8}-cubane. These complementary techniques provide consistent estimates of the lowest level-crossing field. The overall features of the experimental data are explained using an isotropic Heisenberg model, based on three distinct exchange interactions linking the eight CrIII paramagnetic centers (spins s = 3/2), that is supplemented with a relatively large molecular magnetic anisotropy term for the lowest S = 1 multiplet. It is noted that the existence of the anisotropy is clearly evident from the magnetic field dependence of the excitations in the INS measurements, while the magnetization measurements are not sensitive to its effects.

Vaknin, D. [Ames Laboratory; Garlea, Vasile O [ORNL; Demmel, F. [ISIS Facility, Rutherford Appleton Laboratory; Mamontov, Eugene [ORNL; Nojiri, H [Institute for Materials Research, Tohoku University, Sendai, Japan; Martin, Catalin [Florida State University; Chiorescu, Irinel [Florida State University; Qiu, Y. [National Institute of Standards and Technology (NIST); Luban, M. [Ames Laboratory; Kogerler, P. [Ames Laboratory; Fielden, J. [Ames Laboratory; Engelhardt, L [Francis Marion University, Florence, South Sarolina; Rainey, C [Francis Marion University, Florence, South Sarolina

2010-01-01T23:59:59.000Z

56

Measurement of the free neutron-proton analyzing power and spin transfer parameters in the charge exchange region at 790 MeV  

SciTech Connect

The free neutron-proton analyzing power and the spin transfer parameters (K/sub NN/, K/sub SS/, K/sub SL/, and K/sub LL/) were measured at the Los Alamos Meson Physics Facility at 790 MeV between 165/sup 0/ and 180/sup 0/ center of mass. A 40% polarized neutron beam incident on a liquid hydrogen target was used. The recoil protons were momentum analyzed with a magnetic spectrometer to isolate elastic scatters. A large solid angle carbon polarimeter was used to measure the proton polarization. The measurements are the first at this energy and are in basic agreement with pre-existing phase shift solutions. The proton-carbon analyzing power was measured between 500 and 750 MeV. An empirical fit to the proton-carbon analyzing power between 100 and 750 MeV was done.

Ransome, R.D.

1981-07-01T23:59:59.000Z

57

MEASUREMENT OF SINGLE TRANSVERSE-SPIN ASYMMETRY IN FORWARD PRODUCTION OF PHOTONS AND NEUTRONS IN PP COLLSION AT SQUARE ROOT = 200 GEV.  

SciTech Connect

The Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory (BNL) was commissioned for polarized proton-proton collisions, at the center of mass energy {radical}s = 200 GeV during the run in 2001-2002. The authors have measured the single transverse-spin asymmetry A{sub N} for production of photons, neutral pions, and neutrons at the very forward angle. The asymmetries for the photon and neutral pion sample were consistent with zero within the experimental uncertainties. In contrast, the neutron sample exhibited an unexpectedly large asymmetry. This large asymmetry will be used for the non-destructive polarimeter for polarized proton beams at the collision points in the RHIC interaction region.

BAZILEVSKY,A.MAKDISI,Y.ET AL.

2002-09-09T23:59:59.000Z

58

Commissioning the Echo-Seeding Experiment Echo-7 at SLAC  

Science Conference Proceedings (OSTI)

ECHO-7 is a proof-of-principle echo-enabled harmonic generation (EEHG) FEL experiment in the Next Linear Collider Test Accelerator (NLCTA) at SLAC. The experiment is intended to test the EEHG principle at low electron beam energy, 120 MeV, and determine the sensitivities and limitations to understand the expected performance at the higher energy scales and harmonic numbers required for x-ray FELs. In this paper we present the experimental results from the commissioning run of the completed experimental setup which started in April 2010.

Weathersby, S.a E.Colby; Dunning, M.; Gilevich, S.; Hast, C.; Jobe, K.; McCormick, D.; Nelson, J.; Raubenheimer, T.O.; Soong, K.; Stupakov, G.; Szalata, Z.; Walz, D.; Woodley, M.; Xiang, D.; /SLAC; Pernet, P-L.; /Ecole Polytechnique, Lausanne

2011-06-02T23:59:59.000Z

59

Distinguishing S-plus-minus and S-plus-plus electron pairing symmetries by neutron spin resonances in superconducting Sodium-Iron-Cobalt-Arsenic (transitional temperature = 18 Kelvin)  

SciTech Connect

A determination of the superconducting (SC) electron pairing symmetry forms the basis for establishing a microscopic mechansim for superconductivity. For iron pnictide superconductors, the s{sup {+-}}-pairing symmetry theory predicts the presence of a sharp neutron spin resonance at an energy below the sum of hole and electron SC gap energies (E {le} 2{Delta}). Although the resonances have been observed for various iron pnictide superconductors, they are broad in energy and can also be interpreted as arising from the s{sup ++}-pairing symmetry with E {ge} 2{Delta}. Here we use inelastic neutron scattering to reveal a sharp resonance at E = 7 meV in the SC NaFe{sub 0.935}Co{sub 0.045}As (T{sub c} = 18 K). By comparing our experiments with calculated spin-excitations spectra within the s{sup {+-}} and s{sup ++}-pairing symmetries, we conclude that the resonance in NaFe{sub 0.935}Co{sub 0.045}As is consistent with the s{sup {+-}}-pairing symmetry, thus eliminating s{sup ++}-pairing symmetry as a candidate for superconductivity.

Das, Tanmoy [Los Alamos National Laboratory; Balatsky, Alexander V. [Los Alamos National Laboratory; Zhang, Chenglin [University of Tennessee, Knoxville, Tennessee; Li, Haifeng [Institut fur Festkorperforschung, Julich, Germany; Su, Yiki [The University of Tennessee, Knoxville, Tennessee; Nethertom, Tucker [The University of Tennessee, Knoxville, Tennessee; Redding, Caleb [The University of Tennessee, Knoxville, Tennessee; Carr, Scott [The University of Tennessee, Knoxville, Tennessee; Schneidewind, Astrid [Forschungsneutronenquelle Heinz, Garching, Germany; Faulhaber, Enrico [Gemeinsame Forschergruppe HZB, Berlin, Germany; Li, Shiliang [Institute of Physics, Chinese Academy of Sciences, Beijing, China; Yao, Daoxin [Sun Yat-Sen University, Guangzhou, China; Bruckel, Thomas [Institut fur Festkorperforschung, Julich, Germany; Dai, Pengchen [Institute of Physics, Chinese Academy of Sciences, Beijing, China; Sobolev, Oleg [Forschungsneutronenquelle Heinz, Garching, Germany

2012-06-05T23:59:59.000Z

60

Mean Radar Echo Characteristics during Project GALE  

Science Conference Proceedings (OSTI)

The mean radar echo characteristics during the Genesis of Atlantic Lows Experiment (GALE) are presented for the southeastern United States during the 15 January–15 March 1986 field phase of the program. The echo characteristics were derived from ...

Thomas J. Trunk; Lance F. Bosart

1990-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

A measurement of. Delta. sigma. sub L (np), the difference between neutron-proton total cross sections in pure longitudinal spin states  

SciTech Connect

A measurement off {Delta}{sigma}{sub L}(np), the difference between neutron-proton total cross sections in pure longitudinal spin states, is described. The results will help determine the isospin-zero (I = 0) scattering amplitudes, which are not well known above laboratory energies of 500 MeV, whereas the isospin-one (I = 1) amplitudes are fairly well-determined to 1 GeV. Data points were taken at the Los Alamos Meson Physics Facility (LAMPF) at Los Alamos, New Mexico, for five neutron beam energies: 484, 568, 634,720 and 788 MeV; they are the first in this energy range. Polarized neutrons were produced by charge-exchange of polarized protons on a liquid deuterium target (LD{sub 2}). Large-volume neutron counters detected the neutrons that passed through a polarized proton target. The counters subtended a range of solid angles large enough to allow extrapolation of the scattered neutrons to 0{degree}. Two modifications to the LAMPF accelerator system which were made for this work are described. They included a beam buncher,'' which modified the normal rf-time structure of the proton beam and allowed for the selection of peak-energy neutrons by time-of-flight means, and a computerized beam steering program, which reduced systematic effects due to beam motion at the LD{sub 2} target. The experimental values of {Delta}{sigma}{sub L}(np) are found to be consistent with other np data, including preliminary data from SIN and Saclay, but not with some results from Argonne which used a polarized proton beam and a polarized deuteron target. The I = 0 component was extracted from {Delta}{sigma}{sub L}(np) using existing pp data (I = 1), with the unexpected result that {Delta}{sigma}{sub L}(I = 0) was found to be essentially identical in shape to {Delta}{sigma}{sub L}(I = 1). The significance of this is not yet understood.

Beddo, M.E.

1990-10-01T23:59:59.000Z

62

{gamma}-ray spectroscopy of neutron-deficient {sup 110}Te. II. High-spin smooth-terminating structures  

Science Conference Proceedings (OSTI)

High-spin states have been populated in {sub 52}{sup 110}Te via {sup 58}Ni({sup 58}Ni,{alpha}2p{gamma}) reactions at 240 and 250 MeV. The Gammasphere {gamma}-ray spectrometer was used in conjunction with the Microball charged-particle detector. The high-spin (I>30) collective level scheme of {sup 110}Te, up to {approx}45({Dirac_h}/2{pi}), is discussed in this paper. Four new decoupled ({delta}I=2) high-spin structures have been observed for the first time, together with two strongly coupled ({delta}I=1) bands. These bands all show the characteristics of smooth band termination, and are discussed within the framework of the cranked Nilsson-Strutinsky approach.

Paul, E. S.; Evans, A. O.; Boston, A. J.; Nolan, P. J.; Semple, A. T. [Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom); Chiara, C. J.; Fossan, D. B.; Lane, G. J.; Sears, J. M.; Starosta, K. [Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, New York 11794-3800 (United States); Devlin, M.; LaFosse, D. R.; Sarantites, D. G. [Department of Chemistry, Washington University, St. Louis, Missouri 63130 (United States); Freeman, S. J.; Leddy, M. J. [Schuster Laboratory, The University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom); Lee, I. Y.; Macchiavelli, A. O. [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Smith, J. F. [Department of Physics and Astronomy, State University of New York at Stony Brook, Stony Brook, New York 11794-3800 (United States); Schuster Laboratory, The University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom); Afanasjev, A. V. [Department of Physics and Astronomy, Mississippi State University, Mississippi 39762 (United States); Department of Mathematical Physics, Lund Institute of Technology, P. O. Box 118, S-22100 Lund (Sweden); Laboratory of Radiation Physics, Institute of Solid State Physics, University of Latvia, LV 2169 Salaspils, Miera str. 31 (Latvia); Ragnarsson, I. [Department of Mathematical Physics, Lund Institute of Technology, P. O. Box 118, S-22100 Lund (Sweden)

2007-09-15T23:59:59.000Z

63

Pushing and Understanding the Limits of Spin-Exchange ...  

Science Conference Proceedings (OSTI)

... This new scheme for spectral narrowing has led to increased 3He polarization for neutron spin filters polarized by spin ... Lead Organizational Unit: ...

2013-07-23T23:59:59.000Z

64

The Spatial Structure of RASS Echoes  

Science Conference Proceedings (OSTI)

An experiment to observe the spatial distribution of radio acoustic sounding system (RASS) echo intensity and Doppler shift using the MU radar is described. Various transmitting configurations are used to confirm that the RASS signal is focused ...

Peter T. May; Tatsuhiro Adachi; Toshitaka Tsuda; Richard J. Lataitis

1996-12-01T23:59:59.000Z

65

Echo Tomography of Black Hole Accretion Flows  

E-Print Network (OSTI)

We discuss technologies for micro-arcsec echo mapping of black hole accretion flows in Active Galactic Nuclei (AGN). Echo mapping employs time delays, Doppler shifts, and photoionisation physics to map the geometry, kinematics, and physical conditions in the reprocessing region close to a compact time-variable source of ionizing radiation. Time delay maps are derived from detailed analysis of variations in lightcurves at different wavelengths. Echo mapping is a maturing technology at a stage of development similar to that of radio interferometry just before the VLA. The first important results are in, confirming the basic assumptions of the method, measuring the sizes of AGN emission line regions, delivering dozens of black hole masses, and showing the promise of the technique. Resolution limits with existing AGN monitoring datasets are typically ~5-10 light days. This should improve down to 1-2 light days in the next-generation echo mapping experiments, using facilities like Kronos and Robonet that are designed for and dedicated to sustained spectroscopic monitoring. A light day is 0.4 micro-arcsec at redshift 0.1, thus echo mapping probes regions 10^3 times smaller than VLBI, and 10^5 times smaller than HST.

Keith Horne

2003-01-14T23:59:59.000Z

66

Los Alamos director echoes cyber concerns  

NLE Websites -- All DOE Office Websites (Extended Search)

Los Alamos director echoes cyber concerns Los Alamos director echoes cyber concerns Los Alamos director echoes cyber concerns Director Charlie McMillan told a gathering of energy executives that securing the electrical grid is a major concern now and it's only becoming more serious. May 21, 2013 Los Alamos National Laboratory Director Charlie McMillan (right), with, from left, Anthony Cugini of the National Energy Technology Laboratory, Thom Mason of Oak Ridge National Laboratory, and Tomas Diaz de la Rubia of Deloitte Consulting LLP. Los Alamos National Laboratory Director Charlie McMillan (right), with, from left, Anthony Cugini of the National Energy Technology Laboratory, Thom Mason of Oak Ridge National Laboratory, and Tomas Diaz de la Rubia of Deloitte Consulting LLP. Contact Fred deSousa

67

Hook Echoes and Rear-Flank Downdrafts: A Review  

Science Conference Proceedings (OSTI)

Nearly 50 years of observations of hook echoes and their associated rear-flank downdrafts (RFDs) are reviewed. Relevant theoretical and numerical simulation results also are discussed. For over 20 years, the hook echo and RFD have been ...

Paul M. Markowski

2002-04-01T23:59:59.000Z

68

Radar Observations of the Early Evolution of Bow Echoes  

Science Conference Proceedings (OSTI)

The evolution of 273 bow echoes that occurred over the United States from 1996 to 2002 was examined, especially with regard to the radar reflectivity characteristics during the prebowing stage. It was found that bow echoes develop from the ...

Brian A. Klimowski; Mark R. Hjelmfelt; Matthew J. Bunkers

2004-08-01T23:59:59.000Z

69

Gabor Transform Application in Feature Description of Underwater Echo Signal  

Science Conference Proceedings (OSTI)

For the nonstationarity of target echo signals acquired by laser underwater target detecting system and the relevance between target echo signal and noise, in virtue of texture analysis of image processing, Gabor transform is used to localize the target ...

Shubin Yang; Wanlong Cui; Huaxi Wang

2009-12-01T23:59:59.000Z

70

Supercool Neutrons (Ultracold Neutrons)  

E-Print Network (OSTI)

in the USA. Why neutrons? Neutrons possess physical properties that make them valuable investigative tools Spallation Neutron Source (SNS) The world's most intense pulsed accelerator-based neutron source. High Flux Isotope Reactor (HFIR) The highest flux reactor-based neutron source for condensed matter research

Martin, Jeff

71

Spallation-Driven Cold Neutron Sources Dr. Bradley J. Micklich  

E-Print Network (OSTI)

, et al. "Direct observation of fermion spin superposition by neutron interferometry," Physical ReviewNeutron Interferometry with Polarized Spin States Frank Rioux Department of Chemistry CSB|SJU The following paragraph appears in an encyclopedia entry on neutron optics.(1) A description of the original

McDonald, Kirk

72

Spin-Assisted Layer-by-Layer Assembly: Variation of Stratification as Studied with Neutron Reflectivity<xref ref-type="fn" rid="end1"><sup></sup></xref>  

NLE Websites -- All DOE Office Websites (Extended Search)

21/la9014042 21/la9014042 14017 Langmuir 2009, 25(24), 14017-14024 Published on Web 07/06/2009 pubs.acs.org/Langmuir © 2009 American Chemical Society Spin-Assisted Layer-by-Layer Assembly: Variation of Stratification as Studied with Neutron Reflectivity † Eugenia Kharlampieva, ‡ Veronika Kozlovskaya, ‡ Jennifer Chan, ‡ John F. Ankner, § and Vladimir V. Tsukruk* ,‡ ‡ Department of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, and § Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 Received April 20, 2009. Revised Manuscript Received June 10, 2009 We apply neutron reflectivity to probe the internal structure of spin-assisted layer-by-layer (SA-LbL) films composed of electrostatically assembled polyelectrolytes. We find that the level of stratification and the degree of layer

73

Direct evidence of a zigzag spin-chain structure in the honeycomb lattice: A neutron and x-ray diffraction investigation of single-crystal Na2IrO3  

Science Conference Proceedings (OSTI)

We have combined single crystal neutron and x-ray diffractions to investigate the magnetic and crystal structures of the honeycomb lattice $\\rm Na_2IrO_3$. The system orders magnetically below $18.1(2)$~K with Ir$^{4+}$ ions forming zigzag spin chains within the layered honeycomb network with ordered moment of $\\rm 0.22(1)~\\mu_B$/Ir site. Such a configuration sharply contrasts the N{\\'{e}}el or stripe states proposed in the Kitaev-Heisenberg model. The structure refinement reveals that the Ir atoms form nearly ideal 2D honeycomb lattice while the $\\rm IrO_6$ octahedra experience a trigonal distortion that is critical to the ground state. The results of this study provide much-needed experimental insights into the magnetic and crystal structure crucial to the understanding of the exotic magnetic order and possible topological characteristics in the 5$d$-electron based honeycomb lattice.

Ye, Feng [ORNL; Chi, Songxue [ORNL; Cao, Huibo [ORNL; Chakoumakos, Bryan C [ORNL; Fernandez-Baca, Jaime A [ORNL; Custelcean, Radu [ORNL; Qi, Tongfei [University of Kentucky; Korneta, O. B. [University of Kentucky, Lexington; Cao, Gang [University of Kentucky

2012-01-01T23:59:59.000Z

74

Polarized neutrons in RHIC  

Science Conference Proceedings (OSTI)

There does not appear to be any obvious way to accelerate neutrons, polarized or otherwise, to high energies by themselves. To investigate the behavior of polarized neutrons the authors therefore have to obtain them by accelerating them as components of heavier nuclei, and then sorting out the contribution of the neutrons in the analysis of the reactions produced by the heavy ion beams. The best neutron carriers for this purpose are probably {sup 3}He nuclei and deuterons. A polarized deuteron is primarily a combination of a proton and a neutron with their spins pointing in the same direction; in the {sup 3}He nucleus the spins of the two protons are opposite and the net spin (and magnetic moment) is almost the same as that of a free neutron. Polarized ions other than protons may be accelerated, stored and collided in a ring such as RHIC provided the techniques proposed for polarized proton operation can be adapted (or replaced by other strategies) for these ions. This paper discusses techniques for accelerating polarized {sup 3}He nuclei and deuterons.

Courant, E.D.

1998-04-20T23:59:59.000Z

75

Decoherence alias Loschmidt echo of the environment  

E-Print Network (OSTI)

Entanglement between a quantum system and its environment leads to loss of coherence in the former. In general, the temporal fate of coherences is complicated. Here, we establish the connection between decoherence of a central system and fidelity decay in the environment for a variety of situations, including both, energy conserving and dissipative couplings. We show how properties of unitary time evolution of the environment can be inferred from the non-unitary evolution of coherences in the central system. This opens up promising ways for measuring Loschmidt echoes in a variety of situations.

T. Gorin; T. Prosen; T. H. Seligman; W. T. Strunz

2004-05-03T23:59:59.000Z

76

Preliminary results of the echo-seeding experiment at SLAC  

E-Print Network (OSTI)

experiment at NLCTA“, SLAC LDRD programme, “http://EEHG experiment (ECHO-7) at SLAC has gone from the designgeneration experiment at SLAC”, These proceedings, [9] J.H.

Xiang, D.

2010-01-01T23:59:59.000Z

77

POLARIZED NEUTRONS IN RHIC  

SciTech Connect

There does not appear to be any obvious way to accelerate neutrons, polarized or otherwise, to high energies by themselves. To investigate the behavior of polarized neutrons the authors therefore have to obtain them by accelerating them as components of heavier nuclei, and then sorting out the contribution of the neutrons in the analysis of the reactions produced by the heavy ion beams. The best neutron carriers for this purpose are probably {sup 3}He nuclei and deuterons. A polarized deuteron is primarily a combination of a proton and a neutron with their spins pointing in the same direction; in the {sup 3}He nucleus the spins of the two protons are opposite and the net spin (and magnetic moment) is almost the same as that of a free neutron. Polarized ions other than protons may be accelerated, stored and collided in a ring such as RHIC provided the techniques proposed for polarized proton operation can be adapted (or replaced by other strategies) for these ions. To accelerate polarized particles in a ring, one must make provisions for overcoming the depolarizing resonances that occur at certain energies. These resonances arise when the spin tune (ratio of spin precession frequency to orbit frequency) resonates with a component present in the horizontal field. The horizontal field oscillates with the vertical motion of the particles (due to vertical focusing); its frequency spectrum is dominated by the vertical oscillation frequency and its modulation by the periodic structure of the accelerator ring. In addition, the magnet imperfections that distort the closed orbit vertically contain all integral Fourier harmonics of the orbit frequency.

COURANT,E.D.

1998-04-27T23:59:59.000Z

78

Neutron Transversity at Jefferson Lab  

SciTech Connect

Nucleon transversity and single transverse spin asymmetries have been the recent focus of large efforts by both theorists and experimentalists. On-going and planned experiments from HERMES, COMPASS and RHIC are mostly on the proton or the deuteron. Presented here is a planned measurement of the neutron transversity and single target spin asymmetries at Jefferson Lab in Hall A using a transversely polarized {sup 3}He target. Also presented are the results and plans of other neutron transverse spin experiments at Jefferson Lab. Finally, the factorization for semi-inclusive DIS studies at Jefferson Lab is discussed.

Jian-Ping Chen; Xiaodong Jiang; Jen-chieh Peng; Lingyan Zhu

2005-09-07T23:59:59.000Z

79

Architectural and Markovian factors of echo state networks  

Science Conference Proceedings (OSTI)

Echo State Networks (ESNs) constitute an emerging approach for efficiently modeling Recurrent Neural Networks (RNNs). In this paper we investigate some of the main aspects that can be accounted for the success and limitations of this class of models. ... Keywords: Architectural design analysis, Echo state networks, Markovianity, Recurrent neural networks, Sequence processing

Claudio Gallicchio; Alessio Micheli

2011-06-01T23:59:59.000Z

80

Fast LMS/Newton algorithms for stereophonic acoustic echo cancelation  

Science Conference Proceedings (OSTI)

This paper presents a new class of adaptive filtering algorithms to solve the stereophonic acoustic echo cancelation (AEC) problem in teleconferencing systems. While stereophonic AEC may be seen as a simple generalization of the well-known single-channel ... Keywords: LMS/Newton, adaptive filters, lattice orthogonalization, stereo acoustic echo cancellation (AEC)

Harsha I. K. Rao; Behrouz Farhang-Boroujeny

2009-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Echo Size and Asymmetry: Impact on NEXRAD Storm Identification  

Science Conference Proceedings (OSTI)

The effects of echo shape and radar viewing angle on detecting small thunderstorms with the NEXRAD storm identification algorithms are examined. The amorphous low level echo shapes are modeled as ellipses with major axes ranging from 5–15 km and ...

Dennis E. Buechler; Steven J. Goodman

1990-09-01T23:59:59.000Z

82

Mesoscale Surface Pressure and Temperature Features Associated with Bow Echoes  

Science Conference Proceedings (OSTI)

This study examines observed mesoscale surface pressure, temperature, and wind features of bow echoes. Bow-echo events in the area of the Oklahoma Mesonet are selected for study to take advantage of high-resolution surface data. Thirty-six cases ...

Rebecca D. Adams-Selin; Richard H. Johnson

2010-01-01T23:59:59.000Z

83

Dictionary for Sparse Representation of Chirp Echo in Broadband Radar  

E-Print Network (OSTI)

A new dictionary for sparse representation of chirp echo in broadband radar is put forward in this paper. Different with chirplet decomposition which decomposes echo in time-frequency plane, the dictionary transforms the sparsity of target observed by radar in distance range to the sparsity in frequency domain by stretch processing and the sparse representation of echo is realized. Using strict deduction with mathematics, the sparsity of echo in dictionary is proved and the dictionary is orthogonal. In the application property, the construction of dictionary is simple, the parameters that are needed for dictionary can be obtained conveniently and the dictionary is convenient to use. Furthermore, the object of application can be expanded to the echo of multi-component chirps with single freedom degree.

Gao, Lei

2010-01-01T23:59:59.000Z

84

Microsoft Word - EchoPointCommunityWind_CX_2012.docx  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

James Hall James Hall Project Manager - TPC-TPP-4 Proposed Action: Integration of the Echo Point Community Wind Generation Project Categorical Exclusion Applied (from Subpart D, 10 C.F.R. Part 1021): B1.7 - Electronic equipment Location: Umatilla County, Oregon Proposed by: Bonneville Power Administration (BPA) Description of the Proposed Action: In response to Echo Point Community Wind's (Echo Point's) small generator interconnection request, BPA proposes to integrate Echo Point's 10-megawatt wind generation project into its balancing authority (BA). The proposed point of interconnection is the Buttercreek Substation owned by the Umatilla Electric Cooperative (UEC). In order to integrate the proposed generation, BPA will install bi-directional generation metering at the Echo Point generation site.

85

Motional Spin Relaxation in Large Electric Fields  

E-Print Network (OSTI)

We discuss the precession of spin-polarized Ultra Cold Neutrons (UCN) and $^{3}$He atoms in uniform and static magnetic and electric fields and calculate the spin relaxation effects from motional $v\\times E$ magnetic fields. Particle motion in an electric field creates a motional $v\\times E$ magnetic field, which when combined with collisions, produces variations of the total magnetic field and results in spin relaxation of neutron and $^{3}$He samples. The spin relaxation times $T_{1}$ (longitudinal) and $T_{2}$ (transverse) of spin-polarized UCN and $^{3}$He atoms are important considerations in a new search for the neutron Electric Dipole Moment at the SNS \\emph{nEDM} experiment. We use a Monte Carlo approach to simulate the relaxation of spins due to the motional $v\\times E$ field for UCN and for $^{3}$He atoms at temperatures below $600,\\mathrm{mK}$. We find the relaxation times for the neutron due to the $v\\times E$ effect to be long compared to the neutron lifetime, while the $^{3}$He relaxation times may be important for the \\emph{nEDM} experiment.

Riccardo Schmid; B. Plaster; B. W. Filippone

2008-05-16T23:59:59.000Z

86

Nuclear moment measurements of Neutron-rich Aluminum Isotopes Using Spin-polarized RI beams: Determination of the Boundary of the 'Island of Inversion'  

Science Conference Proceedings (OSTI)

The electric quadrupole moment Q for the ground state of 32Al has been measured using the {beta}-NMR technique. Spin-polarized 32Al nuclei were obtained from the fragmentation of 40Ar projectiles at E/A = 95 MeV/nucleon, and were implanted in a single crystal {alpha}-Al2O3 stopper. The quadrupole moment was deduced from the measured quadrupole coupling constant. The obtained value, |Q(32Alg.s.)| = 24(2) mb, was well reproduced by shell model calculations within the sd shell, indicating that 32Al is a normal sd-shell nucleus. The result is in sharp contrast to the strongly deformed nuclei 32Mg and 31Mg neighboring the 32Al isotope.

Kameda, D.; Ueno, H.; Yoshimi, A.; Kobayashi, Y.; Haseyama, T.; Ishihara, M. [RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Asahi, K. [Department of Physics, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro-ku, Tokyo 152-8551 (Japan); RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Takemura, M.; Nagae, D.; Shimada, K.; Uchida, M.; Takase, K.; Arai, T.; Inoue, T.; Suda, S. [Department of Physics, Tokyo Institute of Technology, 2-12-1 Oh-okayama, Meguro-ku, Tokyo 152-8551 (Japan); Murata, J.; Kawamura, H. [Department of physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501 (Japan); Watanabe, H. [Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra AT 0200 (Australia)

2007-06-13T23:59:59.000Z

87

Do Gluons Carry Proton Spin? - Toward Resolving the Spin Crisis (445th Brookhaven Lecture)  

Science Conference Proceedings (OSTI)

Just as Earth and other planets spin within the solar system, subatomic quark and gluon particles spin within the protons and neutrons that spin within the nucleus of an atom. Quantum Chromodynamics (QCD) is a theory that describes interactions between subatomic particles and it has played a defining role in understanding the spin of protons and neutrons, which make up most of the visible mass in the universe. Experiments first completed at CERN and furthered at several other laboratories around the world revealed that surprisingly, quarks and their partnering anti-quarks are responsible for only 20 to 30 percent of proton spin. These findings pointed to what would become known as "spin crisis." More recent experiments at BNL's Relativistic Heavy Ion Collider (RHIC), the first collider to smash protons that are "polarized," or made to spin in the same orientation, have helped to isolate the role of the gluon's spin within the spinning proton in hopes of resolving this crisis. In his lecture, Bazilevsky will explain how data from RHIC's PHENIX and STAR detectors help to reveal the role of gluons in the proton's spin. Bazilevsky will also discuss long- and short-term plans to attain a deeper look into the proton spin structure, utilizing RHIC and its future upgrades

Bazilevsky, Alexander (Physics Dept)

2009-01-21T23:59:59.000Z

88

Sensitivity of Bow Echo Simulation to Microphysical Parameterizations  

Science Conference Proceedings (OSTI)

The sensitivity of a case study bow echo simulation to eight different microphysical schemes in the Weather Research and Forecasting model was tested, with a focus on graupel parameter characteristics. The graupel parameter in one scheme was ...

Rebecca D. Adams-Selin; Susan C. van den Heever; Richard H. Johnson

89

Sensitivity of Bow-Echo Simulation to Microphysical Parameterizations  

Science Conference Proceedings (OSTI)

The sensitivity of a case study bow-echo simulation to eight different microphysical schemes in the Weather Research and Forecasting model was tested, with a focus on graupel parameter characteristics. The graupel parameter in one scheme was ...

Rebecca D. Adams-Selin; Susan C. van den Heever; Richard H. Johnson

2013-10-01T23:59:59.000Z

90

Regional Characteristics for Interpreting Inverted Echo Sounder (IES) Observations  

Science Conference Proceedings (OSTI)

Changes in round-trip acoustc travel time (?) measured between a bottom moored inverted echo sounder and the sea surface can be interpreted as changes in dynamic height (D) with suitable calibration information. The ?, D, and isotherm and ...

Zachariah R. Hallock

1987-06-01T23:59:59.000Z

91

The Bow Echo and MCV Experiment: Observations and Opportunities  

Science Conference Proceedings (OSTI)

The Bow Echo and Mesoscale Convective Vortex Experiment (BAMEX) is a research investigation using highly mobile platforms to examine the life cycles of mesoscale convective systems. It represents a combination of two related investigations to ...

Christopher Davis; Nolan Atkins; Diana Bartels; Lance Bosart; Michael Coniglio; George Bryan; William Cotton; David Dowell; Brian Jewett; Robert Johns; David Jorgensen; Jason Knievel; Kevin Knupp; Wen-Chau Lee; Gregory Mcfarquhar; James Moore; Ron Przybylinski; Robert Rauber; Bradley Smull; Robert Trapp; Stanley Trier; Roger Wakimoto; Morris Weisman; Conrad Ziegler

2004-08-01T23:59:59.000Z

92

Glossary Term - Neutron Emission  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Previous Term (Neutron) Glossary Main Index Next Term (Niobe) Niobe Neutron Emission After neutron emission, an atom contains one less neutron. Neutron emission is one...

93

Ris-M-2874 Neutron Diffraction Experiments  

E-Print Network (OSTI)

;1. Introduction The nuclear spin systems in metals provide ideal models to test theoretical ideas by experiments Roskilde, Denmark August 1990 #12;Abstract Nuclear spins in silver constitute an ideal antiferromagnetic study the feasibility of neutron diffraction experiments on nuclear magnetic order in silver

94

SPINS Publications  

Science Conference Proceedings (OSTI)

... Lee, T. Katsufuji, M. Masaki, S. Park, JRD Copley, and H. Takagi, http://dx.doi.org/10.1103/PhysRevB.68.014432"Unconventional Spin ...

95

Emergent spin  

E-Print Network (OSTI)

Quantum mechanics and relativity in the continuum imply the well known spin-statistics connection. However for particles hopping on a lattice, there is no such constraint. If a lattice model yields a relativistic field theory in a continuum limit, this constraint must "emerge" for physical excitations. We discuss a few models where a spin-less fermion hopping on a lattice gives excitations which satisfy the continuum Dirac equation. This includes such well known systems such as graphene and staggered fermions.

Michael Creutz

2013-08-16T23:59:59.000Z

96

Neutron Radiography  

Science Conference Proceedings (OSTI)

Table 8   Characteristics of neutron radiography at various neutron-energy ranges...Good discrimination between materials and ready availability

97

Neutron Sources  

Science Conference Proceedings (OSTI)

Table 1   Characteristics of neutron radiography at various neutron-energy ranges...Good discrimination between materials, and ready

98

Universal dynamical decoupling of a single solid-state spin from a spin bath  

E-Print Network (OSTI)

Controlling the interaction of a single quantum system with its environment is a fundamental challenge in quantum science and technology. We dramatically suppress the coupling of a single spin in diamond with the surrounding spin bath by using double-axis dynamical decoupling. The coherence is preserved for arbitrary quantum states, as verified by quantum process tomography. The resulting coherence time enhancement is found to follow a general scaling with the number of decoupling pulses. No limit is observed for the decoupling action up to 136 pulses, for which the coherence time is enhanced more than 25 times compared to spin echo. These results uncover a new regime for experimental quantum science and allow to overcome a major hurdle for implementing quantum information protocols.

de Lange, G; Ristè, D; Dobrovitski, V V; Hanson, R

2010-01-01T23:59:59.000Z

99

Universal dynamical decoupling of a single solid-state spin from a spin bath  

E-Print Network (OSTI)

Controlling the interaction of a single quantum system with its environment is a fundamental challenge in quantum science and technology. We dramatically suppress the coupling of a single spin in diamond with the surrounding spin bath by using double-axis dynamical decoupling. The coherence is preserved for arbitrary quantum states, as verified by quantum process tomography. The resulting coherence time enhancement is found to follow a general scaling with the number of decoupling pulses. No limit is observed for the decoupling action up to 136 pulses, for which the coherence time is enhanced more than 25 times compared to spin echo. These results uncover a new regime for experimental quantum science and allow to overcome a major hurdle for implementing quantum information protocols.

G. de Lange; Z. H. Wang; D. Ristè; V. V. Dobrovitski; R. Hanson

2010-08-12T23:59:59.000Z

100

Kangley - Echo Lake Transmission Line Project, Final Environmental Impact Statement  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

STATEMENT STATEMENT Kangley-Echo Lake Transmission Line Project Final Environmental Impact Statement Responsible Agency: U.S. Department of Energy, Bonneville Power Administration (BPA) Cooperating Agency: U.S. Department of Agriculture, Forest Service (USFS) Title of Proposed Project: Kangley-Echo Lake Transmission Line Project State Involved: Washington Abstract: BPA is proposing to build a new transmission line to accommodate increasing demand for electricity and ensure reliability in the Puget Sound area. The Proposed Action would construct a new line that would connect to an existing transmis- sion line near the community of Kangley, and then connect with BPA's existing Echo Lake Substation. The major purpose of this proposal is to improve system reliability in the King County area. An outage on an existing line during times of heavy use, such as

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Spin Stability  

NLE Websites -- All DOE Office Websites (Extended Search)

Stability Stability of Asymmetrically Charged Plasma Dust I. H. Hutchinson Plasma Science and Fusion Center Massachusetts Institute of Technology, Cambridge, MA, USA Recently it has been reported that, under some circumstances, dust particles sus- pended in the sheath edge are observed to spin [1, 2, 3]. The present paper shows that there is a natural electrostatic mechanism that should cause even perfectly spherical par- ticles in a perfectly irrotational, magnetic-field-free flowing plasma to spin. The stability criterion and the final spin state are obtained[4]. When the particle is made of an insulating material, it can support potential dif- ferences around its surface. In the limit of zero conductivity, and ignoring all charging effects other than electron or ion collection, the surface charge density accumulates in such a way as to bring the local electric current density to zero.

102

Old and new neutron stars  

Science Conference Proceedings (OSTI)

The youngest known radiopulsar in the rapidly spinning magnetized neutron star which powers the Crab Nebula, the remnant of the historical supernova explosion of 1054 AD. Similar neutron stars are probably born at least every few hundred years, but are less frequent than Galactic supernova explosions. They are initially sources of extreme relativistic electron and/or positron winds (approx.10/sup 38/s/sup -1/ of 10/sup 12/ eV leptons) which greatly decrease as the neutron stars spin down to become mature pulsars. After several million years these neutron stars are no longer observed as radiopulsars, perhaps because of large magnetic field decay. However, a substantial fraction of the 10/sup 8/ old dead pulsars in the Galaxy are the most probable source for the isotropically distributed ..gamma..-ray burst detected several times per week at the earth. Some old neutron stars are spun-up by accretion from companions to be resurrected as rapidly spinning low magnetic field radiopulsars. 52 references, 6 figures, 3 tables.

Ruderman, M.

1984-09-01T23:59:59.000Z

103

Glossary Term - Neutron  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutrino Previous Term (Neutrino) Glossary Main Index Next Term (Neutron Emission) Neutron Emission Neutron A Neutron Neutrons are uncharged particles found within atomic nuclei....

104

About Neutrons  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Basics Neutron Basics A neutron is one of the fundamental particles that make up matter. This uncharged particle exists in the nucleus of a typical atom, along with its positively charged counterpart, the proton. Protons and neutrons each have about the same mass, and both can exist as free particles away from the nucleus. In the universe, neutrons are abundant, making up more than half of all visible matter. Find Out What a Neutron Is Youtube icon Properties of Neutrons How Can Neutrons Be Used for Research? Image of glucose movement in plants Neutron imaging techniques have been able to determine the precise movement of glucose in plants. This knowledge can help scientists better understand how biomass can be efficiently converted into fuel. Neutrons have many properties that make them ideal for certain types of

105

The Bow Echo: Observations, Numerical Simulations, and Severe Weather Detection Methods  

Science Conference Proceedings (OSTI)

Bowing convective line segments (bow echoes) are often associated with swaths of damaging downburst winds and are sometimes accompanied by tornadoes that may reach violent (F4) intensity. Bow echoes range in length from less than 20 km to more ...

Ron W. Przybylinski

1995-06-01T23:59:59.000Z

106

Radar and Damage Analysis of Severe Bow Echoes Observed during BAMEX  

Science Conference Proceedings (OSTI)

This study examines damaging-wind production by bow-shaped convective systems, commonly referred to as bow echoes. Recent idealized numerical simulations suggest that, in addition to descending rear inflow at the bow echo apex, low-level ...

Dustan M. Wheatley; Robert J. Trapp; Nolan T. Atkins

2006-03-01T23:59:59.000Z

107

Population Characteristics, Development Processes and Structure of Radar Echoes in South Florida  

Science Conference Proceedings (OSTI)

Radar data from the Florida Area Cumulus Experiment were used to study the ensemble characteristics of echo populations and also the structure of echo systems and their phenomenological growth and development process. The diurnal development of ...

Raúl E. López; David O. Blanchard; Daniel Rosenfeld; William L. Hiscox; Marjorie J. Casey

1984-01-01T23:59:59.000Z

108

Acoustical Measurement of Nonlinear Internal Waves Using the Inverted Echo Sounder  

Science Conference Proceedings (OSTI)

The performance of pressure sensor–equipped inverted echo sounders for monitoring nonlinear internal waves is examined. The inverted echo sounder measures the round-trip acoustic travel time from the sea floor to the sea surface and thus acquires ...

Qiang Li; David M. Farmer; Timothy F. Duda; Steve Ramp

2009-10-01T23:59:59.000Z

109

Coherent spin control by electromagnetic vacuum fluctuations  

SciTech Connect

In coherent control, electromagnetic vacuum fluctuations usually cause coherence loss through irreversible spontaneous emission. However, since the dissipation via emission is essentially due to correlation of the fluctuations, when emission ends in a superposition of multiple final states, correlation between different pathways may build up if the 'which way' information is not fully resolved (i.e., the emission spectrum is broader than the transition energy range). Such correlation can be exploited for spin-flip control in a {Lambda}-type three-level system, which manifests itself as an all-optical spin echo in nonlinear optics with two orders of optical fields saved as compared with stimulated Raman processes. This finding represents a class of optical nonlinearity induced by electromagnetic vacuum fluctuations.

Wang Jing [Department of Physics, Chinese University of Hong Kong, Shatin, N.T. (Hong Kong); Department of Physics, Tsinghua University, Beijing 100084 (China); Liu Renbao [Department of Physics, Chinese University of Hong Kong, Shatin, N.T. (Hong Kong); Zhu Bangfen [Department of Physics, Tsinghua University, Beijing 100084 (China); Institute of Advanced Study, Tsinghua University, Beijing 100084 (China); Sham, L. J. [Department of Physics, University of California-San Diego, La Jolla, California 92093-0319 (United States); Steel, D. G. [H. M. Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2011-05-15T23:59:59.000Z

110

Echo 1-7 Wind Farm | Open Energy Information  

Open Energy Info (EERE)

Echo 1-7 Wind Farm Echo 1-7 Wind Farm Jump to: navigation, search Name Echo 1-7 Wind Farm Facility Echo 1-7 Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner John Deere Wind Developer John Deere Wind Energy Purchaser PacifiCorp Location Morrow and Umatilla Counties OR Coordinates 45.521953°, -119.248549° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":45.521953,"lon":-119.248549,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

111

Echo 8-9 Wind Farm | Open Energy Information  

Open Energy Info (EERE)

Echo 8-9 Wind Farm Echo 8-9 Wind Farm Jump to: navigation, search Name Echo 8-9 Wind Farm Facility Echo 8-9 Sector Wind energy Facility Type Commercial Scale Wind Facility Status In Service Owner John Deere Wind Developer John Deere Wind Energy Purchaser PacifiCorp Location Morrow and Umatilla Counties OR Coordinates 45.521953°, -119.248549° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":45.521953,"lon":-119.248549,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

112

Climatology of Anomalous Propagation Radar Echoes in a Coastal Area  

Science Conference Proceedings (OSTI)

Anomalous propagation (AP) of ground-based radar beam results in the detection of ground echoes beyond the horizon. One year of data gathered with an S-band meteorological radar located on the coast in southwest France is used to analyze the ...

Frédéric Mesnard; Henri Sauvageot

2010-11-01T23:59:59.000Z

113

The Genesis of Severe, Long-Lived Bow Echoes  

Science Conference Proceedings (OSTI)

A series of idealized simulations using a nonhydrostatic cloud model is used to investigate the genesis of bow echoes (a bow-shaped system of convective cells that is especially noted for producing long swaths of damaging surface winds). It is ...

Morris L. Weisman

1993-02-01T23:59:59.000Z

114

Echo phenomenon associated with lower-hybrid-wave launching  

DOE Green Energy (OSTI)

Lower hybrid waves at two different frequencies f/sub 1/ and f/sub 2/ are launched simultaneously from two localized antennas, and a third wave is observed to arise near the plasma edge at the frequency f = f/sub 2/ - f/sub 1/. This phenomenon can be explained by an echo effect near the plasma surface.

Wong, K.L.; Skiff, F.; Ono, M.

1983-06-01T23:59:59.000Z

115

Calibrating Inverted Echo Sounders Equipped with Pressure Sensors  

Science Conference Proceedings (OSTI)

The addition of an accurate pressure sensor to the inverted echo sounder (IES) has allowed for the development of a new method for calibrating the IES’s acoustic travel-time record without the need for coincident conductivity–temperature–depth (...

Christopher S. Meinen; D. Randolph Watts

1998-12-01T23:59:59.000Z

116

An Autonomously Recording Inverted Echo Sounder: ARIES II  

Science Conference Proceedings (OSTI)

A self-contained instrument, the Autonomously Recording Inverted Echo Sounder (ARIES II), carrying two 250-kHz beam side-scan sonars and with the capacity to record sonar data sampled at 3.2 kHz for 168 h with the sonars operating with a pulse ...

S. A. Thorpe; M. J. Ulloa; D. Baldwin; A. J. Hall

1998-12-01T23:59:59.000Z

117

NSE 2009 - Workshop on Neutron Spin  

NLE Websites -- All DOE Office Websites (Extended Search)

some innovative components like fully compensated superconducting coils and a magnetic shield reducing its sensitivity to stray fields, as well as new developed correction elements...

118

Damaging Surface Wind Mechanisms within the 10 June 2003 Saint Louis Bow Echo during BAMEX  

Science Conference Proceedings (OSTI)

Detailed radar and damage survey analyses of a severe bow echo event that occurred on 10 June 2003 during the Bow Echo and Mesoscale Convective Vortex (MCV) Experiment are presented. A bow echo formed just east of Saint Louis, Missouri, and ...

Nolan T. Atkins; Christopher S. Bouchard; Ron W. Przybylinski; Robert J. Trapp; Gary Schmocker

2005-08-01T23:59:59.000Z

119

High Winds Generated by Bow Echoes. Part I: Overview of the Omaha Bow Echo 5 July 2003 Storm during BAMEX  

Science Conference Proceedings (OSTI)

An analysis of a bow echo that produced damaging winds exceeding F1 in intensity on the Fujita scale near Omaha, Nebraska, is shown. Part I of this study presents a combination of airborne Doppler-derived wind syntheses with a comprehensive ...

Roger M. Wakimoto; Hanne V. Murphey; Albert Nester; David P. Jorgensen; Nolan T. Atkins

2006-10-01T23:59:59.000Z

120

Neutron dosimetry  

DOE Patents (OSTI)

A method of measuring neutron radiation within a nuclear reactor is provided. A sintered oxide wire is disposed within the reactor and exposed to neutron radiation. The induced radioactivity is measured to provide an indication of the neutron energy and flux within the reactor.

Quinby, Thomas C. (Kingston, TN)

1976-07-27T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Superconductivity | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Research Highlights Research Highlights Superconductivity Neutron diffraction reveals semiconducting phase and contributes to new understanding of iron-based superconductors Contact: Huibo Cao New VULCAN tests of Japanese cable for US ITER's central magnet system (2012) Contact: Ke An ARCS maps collaborative magnetic spin behavior in iron telluride (2011) Published Work: "Unconventional Temperature Enhanced Magnetism in Fe1:1Te" Contact: Igor Zaliznyak Doug Scalapino discusses "common thread" linking unconventional superconducting materials (2011) Contact: Douglas Scalapino Materials Engineering Research at SNS Helps International Collaboration on Fusion Energy Scientists and engineers at ORNL are working with the ITER Organization and the Japanese Atomic Energy Agency to resolve issues with a critical

122

Demand Response Spinning Reserve Demonstration  

E-Print Network (OSTI)

F) Enhanced ACP Date RAA ACP Demand Response – SpinningReserve Demonstration Demand Response – Spinning Reservesupply spinning reserve. Demand Response – Spinning Reserve

2007-01-01T23:59:59.000Z

123

Benefits of the Multiple Echo Technique for Ultrasonic Thickness Testing  

SciTech Connect

Much effort has been put into determining methods to make accurate thickness measurements, especially at elevated temperatures. An accuracy of +/- 0.001 inches is typically noted for commercial ultrasonic thickness gauges and ultrasonic thickness techniques. Codes and standards put limitations on many inspection factors including equipment, calibration tolerance and temperature variations. These factors are important and should be controlled, but unfortunately do not guarantee accurate and repeatable measurements in the field. Most technicians long for a single technique that is best for every situation, unfortunately, there are no 'silver bullets' when it comes to nondestructive testing. This paper will describe and discuss some of the major contributors to measurement error as well as some advantages and limitations of multiple echo techniques and why multiple echo techniques should be more widely utilized for ultrasonic thickness measurements.

Elder, J.; Vandekamp, R.

2011-02-10T23:59:59.000Z

124

Glen Echo, Maryland: Energy Resources | Open Energy Information  

Open Energy Info (EERE)

Echo, Maryland: Energy Resources Echo, Maryland: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 38.9689993°, -77.1424791° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":38.9689993,"lon":-77.1424791,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

125

Multi mode nano scale Raman echo quantum memory  

E-Print Network (OSTI)

Low loss magnetic surface plasmon polariton (SPP) modes characterized by enhanced electrical field component and subwavelength confinement on the dielectric and negative-index metamaterial interface are presented. We demonstrate a possibility of storage and perfect retrieval of the low loss magnetic SPP fields by using a photon echo quantum memory on Raman atomic transition. We describe specific properties of the proposed technique which opens a possibility for efficient nano scale multi-mode quantum memory.

S. A. Moiseev; E. S. Moiseev

2010-01-31T23:59:59.000Z

126

Geomagnetic control of polar mesosphere summer echoes , P. Homann1  

E-Print Network (OSTI)

Geomagnetic control of polar mesosphere summer echoes J. Bremer1 , P. Homann1 , T. L. Hansen2 1 in dependence on geomagnetic K indices derived at the Auroral Observa- tory Tromsù (69.66°N, 18.94°E). During) of the radar results and the geomagnetic K indices could be detected with a maxi- mum correlation near midnight

Paris-Sud XI, Université de

127

THIRTY YEARS OF SN 1980K: EVIDENCE FOR LIGHT ECHOES  

Science Conference Proceedings (OSTI)

We report optical and mid-infrared photometry of SN 1980K between 2004 and 2010, which shows slow monotonic fading consistent with previous spectroscopic and photometric observations made 8-17 yr after outburst. The slow rate of change over two decades suggests that this evolution may result from scattered and thermal light echoes off of extended circumstellar material. We present a semi-analytic dust radiative-transfer model that uses an empirically corrected effective optical depth to provide a fast and robust alternative to full Monte Carlo radiative-transfer modeling for homogenous dust at low to intermediate optical depths. We find that unresolved echoes from a thin circumstellar shell 14-15 lt-yr from the progenitor, and containing {approx}< 0.02 M{sub Sun} of carbon-rich dust, can explain the broadband spectral and temporal evolution. The size, mass, and dust composition are in good agreement with the contact discontinuity observed in scattered echoes around SN 1987A. The origin of slowly changing high-velocity [O I] and H{alpha} lines is also considered. We propose an origin in shocked high-velocity metal-rich clumps of ejecta, rather than arising in the impact of ejecta on slowly moving circumstellar material, as is the case with hot spots in SN 1987A.

Sugerman, Ben E. K. [Department of Physics and Astronomy, Goucher College, 1021 Dulaney Valley Road, Baltimore, MD 21208 (United States); Andrews, Jennifer E. [Department of Astronomy, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); Barlow, Michael J. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Clayton, Geoffrey C. [Department of Physics and Astronomy, Lousiana State University, 202 Nicholson Hall, Baton Roughe, LA 70803 (United States); Ercolano, Barbara [Excellence Cluster 'Universe', Universitaets-Sternwarte Muenchen, Scheinerstr. 1, 81679 Muenchen (Germany); Ghavamian, Parviz [Department of Physics, Astronomy and Geosciences, Towson University, Smith Hall, Towson, MD 21252 (United States); Kennicutt, Robert C. Jr. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CM3 0HA (United Kingdom); Krause, Oliver [Max Planck Institute for Astronomy, Koenigstuhl 17, 69117 Heidelberg (Germany); Meixner, Margaret [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Otsuka, Masaaki, E-mail: ben.sugerman@goucher.edu [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China)

2012-04-20T23:59:59.000Z

128

Magnetism Highlights| Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnetism Magnetism SHARE Magnetism Highlights 1-5 of 5 Results ARCS maps collaborative magnetic spin behavior in iron telluride December 01, 2011 - Researchers have long thought that magnetism and superconductivity are mutually exclusive. The former typically involves localized atomic electrons. The latter requires freely propagating, itinerant electrons. Unexpected Magnetic Excitations in Doped Insulator Surprise Researchers October 01, 2011 - When doping a disordered magnetic insulator material with atoms of a nonmagnetic material, the conventional wisdom is that the magnetic interactions between the magnetic ions in the material will be weakened. Neutron Analysis Reveals Unique Atomic-Scale Behavior of "Cobalt Blue" September 01, 2011 - Neutron scattering studies of "cobalt blue," a

129

Research Highlights | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Superconductivity Superconductivity Research Highlights Superconductivity Archive New Neutron Studies Support Magnetism's Role in Superconductors Recent neutron scattering experiments give strong evidence that if superconductivity is related to a material's magnetic properties, the same mechanisms are behind both copper-based, high-temperature superconductors and the newly discovered iron-based superconductors. The research was performed at SNS and HFIR and the ISIS Facility at Rutherford Appleton Laboratory in England. (2010) Published Work: "Evolution of spin excitations into the superconducting state in FeTe1-xSex" Contact: Mark Lumsden Advances in Unconventional Iron-Based Superconductors The discovery of more diverse superconducting materials will lead to more

130

Cold neutrons trapped in external fields  

E-Print Network (OSTI)

The properties of inhomogeneous neutron matter are crucial to the physics of neutron-rich nuclei and the crust of neutron stars. Advances in computational techniques now allow us to accurately determine the binding energies and densities of many neutrons interacting via realistic microscopic interactions and confined in external fields. We perform calculations for different external fields and across several shells to place important constraints on inhomogeneous neutron matter, and hence the large isospin limit of the nuclear energy density functionals that are used to predict properties of heavy nuclei and neutron star crusts. We find important differences between microscopic calculations and current density functionals; in particular the isovector gradient terms are significantly more repulsive than in traditional models, and the spin-orbit and pairing forces are comparatively weaker.

S. Gandolfi; J. Carlson; Steven C. Pieper

2010-10-21T23:59:59.000Z

131

Demand Response Spinning Reserve  

NLE Websites -- All DOE Office Websites (Extended Search)

Demand Response Spinning Reserve Title Demand Response Spinning Reserve Publication Type Report Year of Publication 2007 Authors Eto, Joseph H., Janine Nelson-Hoffman, Carlos...

132

Deformation and shape transitions in hot rotating neutron deficient Te isotopes  

SciTech Connect

Evolution of the nuclear shapes and deformations under the influence of temperature and rotation is investigated in Te isotopes with neutron number ranging from the proton drip line to the stability valley. Spin dependent critical temperatures for the shape transitions in Te nuclei are computed. Shape transitions from prolate at low temperature and spin to oblate via triaxiality are seen with increasing neutron number and spin.

Aggarwal, Mamta [UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Kalina Campus, Mumbai 400 098 (India); Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005 (India); Mazumdar, I. [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400 005 (India)

2009-08-15T23:59:59.000Z

133

Neutron Sources  

Science Conference Proceedings (OSTI)

... for Neutron Reaction Rate Measurements, JA Grundl, V. Spiegel, CM Eisenhauer, HT Heaton II, DM Gilliam (NBS), and J. Bigelow (ORNL), Nucl. ...

2013-07-27T23:59:59.000Z

134

Leading neutrons from polarized pp collisions  

SciTech Connect

We calculate the cross section and single-spin azimuthal asymmetry, A{sub n}(t) for inclusive neutron production in pp collisions at forward rapidities relative to the polarized proton. Absorptive corrections to the pion pole generate a relative phase between the spin-flip and non-flip amplitudes, which leads to an appreciable spin asymmetry. However, the asymmetry observed recently in the PHENIX experiment at RHIC at very small |t|{approx}0.01 GeV{sup 2} cannot be explained by this mechanism.

Kopeliovich, B. Z. [Departamento de Fisica y Centro de Estudios Subatomicos, Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile); Institut fuer Theoretische Physik der Universitaet, Philosophenweg 19, 69120 Heidelberg (Germany); Potashnikova, I. K.; Schmidt, Ivan [Departamento de Fisica y Centro de Estudios Subatomicos, Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile); Soffer, J. [Department of Physics, Temple University, Philadelphia, PA 19122-6082 (United States)

2008-10-13T23:59:59.000Z

135

Mixed-Spin Pairing Condensates in Heavy Nuclei  

Science Conference Proceedings (OSTI)

We show that the Bogoliubov-de Gennes equations for nuclear ground-state wave functions support solutions in which the condensate has a mixture of spin-singlet and spin-triplet pairing. We find that such mixed-spin condensates do not occur when there are equal numbers of neutrons and protons, but only when there is an isospin imbalance. Using a phenomenological Hamiltonian, we predict that such nuclei may occur in the physical region within the proton dripline. We also solve the Bogoliubov-de Gennes equations with variable constraints on the spin-singlet and spin-triplet pairing amplitudes. For nuclei that exhibit this new pairing behavior, the resulting energy surface can be rather soft, suggesting that there may be low-lying excitations associated with the spin mixing.

Gezerlis, Alexandros; Luo, Y. L. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Bertsch, G. F. [Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195-1560 (United States)

2011-06-24T23:59:59.000Z

136

Electrical activation and spin coherence of ultra low doseantimony implants in silicon  

DOE Green Energy (OSTI)

We implanted ultra low doses (0.2 to 2 x 10{sup 11} cm{sup -2}) of Sb ions into isotopically enriched {sup 28}Si, and probed electrical activation and electron spin relaxation after rapid thermal annealing. Strong segregation of dopants towards both Si{sub 3}N{sub 4} and SiO{sub 2} interfaces limits electrical activation. Pulsed Electron Spin Resonance shows that spin echo decay is sensitive to the dopant profiles, and the interface quality. A spin decoherence time, T{sub 2}, of 1.5 ms is found for profiles peaking 25 nm below a Si/SiO{sub 2} interface, increasing to 2.1 ms when the surface is passivated with hydrogen. These measurements provide benchmark data for the development of devices in which quantum information is encoded in donor electron spins.

Schenkel, T.; Tyryshkin, A.M.; de Sousa, R.; Whaley, K.B.; Bokor,J.; Liddle, J.A.; Persaud, A.; Shangkuan, J.; Chakarov, I.; Lyon, S.A.

2005-07-13T23:59:59.000Z

137

Slow neutron detection without 3He: far ultraviolet noble-gas-excimer radiation  

E-Print Network (OSTI)

that lowest end, often referred to as fast-neutron physics, falls outside the announced interests of NSSA have on neutron studies generally and on physics generally. Will it encourage formation of other spin-off groups promoting their special inter- ests--for example, an American So- ciety for Fast-Neutron Physics

Titov, Anatoly

138

Superconductivity Highlights | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Superconductivity Superconductivity SHARE Superconductivity Highlights 1-6 of 6 Results Doug Scalapino discusses "common thread" linking unconventional superconducting materials December 01, 2012 - Douglas Scalapino was the inaugural speaker for a new joint lecture series sponsored by the Spallation Neutron Source and the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory. New VULCAN tests of Japanese cable for US ITER's central magnet system February 01, 2012 - Neutron testing of the Japanese-made superconducting cable for the central solenoid (CS) magnetic system for US ITER begins next Tuesday, says Ke An, lead instrument scientist for the VULCAN Engineering Materials Diffractometer at the Spallation Neutron Source. ARCS maps collaborative magnetic spin behavior in iron telluride

139

Neutronic reactor  

DOE Patents (OSTI)

A safety rod for a nuclear reactor has an inner end portion having a gamma absorption coefficient and neutron capture cross section approximately equal to those of the adjacent shield, a central portion containing materials of high neutron capture cross section and an outer end portion having a gamma absorption coefficient at least equal to that of the adjacent shield.

Wende, Charles W. J. (West Chester, PA)

1976-08-17T23:59:59.000Z

140

RHIC SPIN FLIPPER  

Science Conference Proceedings (OSTI)

This paper proposes a new design of spin flipper for RHIC to obtain full spin flip with the spin tune staying at half integer. The traditional technique of using an rf dipole or solenoid as spin flipper to achieve full spin flip in the presence of full Siberian snake requires one to change the snake configuration to move the spin tune away from half integer. This is not practical for an operational high energy polarized proton collider like RHIC where beam lifetime is sensitive to small betatron tune change. The design of the new spin flipper as well as numerical simulations are presented.

BAI,M.; ROSER, T.

2007-06-25T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

RHIC | Spin Physics  

NLE Websites -- All DOE Office Websites (Extended Search)

Spin Physics Spin Physics RHIC is the world's only machine capable of colliding high-energy beams of polarized protons, and is a unique tool for exploring the puzzle of the proton's 'missing' spin. In addition to colliding heavy ions, RHIC is able to collide single protons. While these collisions don't produce quark-gluon plasma, they're interesting to physicists for other reasons. Scientists want to know more about a property of particles called 'spin'. Spin is the direction a particle is spinning around an axis as it travels -- just like the Earth spins on its axis as it travels around the sun. Each proton has a specific spin, which helps give it a characteristic magnetic property. spin In this picture of a proton-proton collision, the spin of the particles is shown as arrows circling the spherical particles. The red and green

142

Neutron source  

DOE Patents (OSTI)

A neutron source which is particularly useful for neutron radiography consists of a vessel containing a moderating media of relatively low moderating ratio, a flux trap including a moderating media of relatively high moderating ratio at the center of the vessel, a shell of depleted uranium dioxide surrounding the moderating media of relatively high moderating ratio, a plurality of guide tubes each containing a movable source of neutrons surrounding the flux trap, a neutron shield surrounding one part of each guide tube, and at least one collimator extending from the flux trap to the exterior of the neutron source. The shell of depleted uranium dioxide has a window provided with depleted uranium dioxide shutters for each collimator. Reflectors are provided above and below the flux trap and on the guide tubes away from the flux trap.

Cason, J.L. Jr.; Shaw, C.B.

1975-10-21T23:59:59.000Z

143

Neutron Polarizers Based on Polarized 3He  

SciTech Connect

The goal of this work, which is a collaborative effort between Indiana University, NIST, and Hamilton College, is to extend the technique of polarized neutron scattering into new domains by the development and application of polarized 3He-based neutron spin filters. After the IPNS experiment which measured Zeeman sp[litting in surface scattered neutrons using a polarized 3He cell as a polarization analyzer transporterd by car from Bloomington to Chicago, the Indiana work focused on technical developments to improve the 3He polarization of the Indiana compression system. The compression system was rebuilt with a new valve system which allows gas trapped in the dead volume of the compressors at the end of the piston stroke to be exhausted and conducted back to the optical pumping cell where it can be repolarized. We also incorporated a new intermediate storage volume made at NIST from 1720 glass which will reduce polarization losses between the compressors. Furthermore, we improved the stability of the 1083 nm laser by cooling the LMA rod. We achieved 60% 3he polarization in the optical pumping cell and 87% preservation of the polarization during compression. In parallel we built a magnetically-shielded transport solenoid for use on neutron scattering instruments such as POSY which achieves a fractional field uniformity of better than 10-3 per cm. The field was mapped using an automated 3D field mapping system for in-situ measurement of magnetic field gradients Diluted magnetic semiconductors offer many exciting opportunities for investigation of spintronic effects in solids and are certain to be one of the most active areas of condensed matter physics over then next several years. These materials can act as efficient spin injectors for devices that make use of spin-dependent transport phenomena. We just (late July 2002) finished a neutron reflectivity experiment at NIST on a GaMnAs trilayer film. This material is a ferromagnetic semiconductor which is of interest for possible applications in spintronics. With the temperature at 12 K and H=235G which saturated both layers' moment to be parallel to the guide field we saw ferromagnetic alignment (FM) of the two outer layers. We also have evidence that the two magnetic layers have different Tc's, and can therefore be used to fabricate a spin-valve. We see a peak at a location in q-space that could correspond to an anti-ferromagnetic state. Finally, we made progress in assembling a spin-exchange optical pumping system which will eventually be relocated to IPNS as an on-site neutron spin filter. As this is written we are preparing for the first effort to optically pump 3He using spin exchange at Indiana. This device will be operational before the end of the present grant. The goal of the work funded by the subcontract to Hamilton College was to support the work of NIST and Indiana in developing 3He-based neutron spin filters for use in polarized neutron scattering applications. Most of the grant period was used by Hamilton to construct the required infrastructure, including 3He cell filling and NMR systems. The main achievement at Hamiltonin is the successful operation of the spin exchange filling system to make a 3He spin exchange cell with a spin relaxation time of 300 hours. This very long relaxation time bodes well for the further development of spin exchange 3He spin filters. Hamilton also constructed a portable NMR device that was used at Indiana to conduct the compression system measurements.

William M. Snow

2005-05-01T23:59:59.000Z

144

Spin structure in high energy processes: Proceedings  

Science Conference Proceedings (OSTI)

This report contains papers as the following topics: Spin, Mass, and Symmetry; physics with polarized Z{sup 0}s; spin and precision electroweak physics; polarized electron sources; polarization phenomena in quantum chromodynamics; polarized lepton-nucleon scattering; polarized targets in high energy physics; spin dynamics in storage rings and linear accelerators; spin formalism and applications to new physics searches; precision electroweak physics at LEP; recent results on heavy flavor physics from LEP experiments using 1990--1992 data; precise measurement of the left-right cross section asymmetry in Z boson production by electron-positron collisions; preliminary results on heavy flavor physics at SLD; QCD tests with SLD and polarized beams; recent results from TRISTAN at KEK; recent B physics results from CLEO; searching for the H dibaryon at Brookhaven; recent results from the compton observatory; the spin structure of the deuteron; spin structure of the neutron ({sup 3}HE) and the Bjoerken sum rule; a consumer`s guide to lattice QCD results; top ten models constrained by b {yields} sy; a review of the Fermilab fixed target program; results from the D0 experiment; results from CDF at FNAL; quantum-mechanical suppression of bremsstrahlung; report from the ZEUS collaboration at HERA; physics from the first year of H1 at HERA, and hard diffraction. These papers have been cataloged separately elsewhere.

DePorcel, L.; Dunwoodie, C. [eds.

1994-12-01T23:59:59.000Z

145

DD1, Enhanced Spin Injection and Spin Lifetimes in Graphene  

Science Conference Proceedings (OSTI)

Gate tunable spin transport and spin precession in non-local single layer graphene (SLG) spin valves at room temperature (RT) were was demonstrated in 2007.

146

Charge stripes and spin correlations in copper-oxide superconductors  

E-Print Network (OSTI)

Recent neutron diffraction studies have yielded evidence that, in a particular cuprate family, holes doped into the CuO2 planes segregate into stripes that separate antiferromagnetic domains. Here it is shown that such a picture provides a quantitatively consistent interpretation of the spin fluctuations measured by neutron diffraction in La1.85Sr0.15CuO4 and YBa2Cu3O6+x. 1.

J. M. Tranquada A

1997-01-01T23:59:59.000Z

147

A Neutron Star in F-sharp  

E-Print Network (OSTI)

In this short introductory commentary on the paper (Hessels et al 2006, Science, 311, 1901) reporting the discovery of the shortest spin period millisecond pulsar (MSP) Ter5-ad in the globular cluster Terzan 5, I also point out a new explanation for possible minimum spin periods, P, of MSPs without requiring gravitational radiation (or other) slow-down torques. If the accretion of matter required to spinup a MSP also reduces (buries) the neutron star (NS) magnetic field, B, as commonly believed, an inverse correlation between neutron star mass, M, and B is expected together with a positive correlation between P and B. Both are suggested for the 4 MSPs with NS mass measures reported (Latimer and Prakash 2004, Science, 304, 536) to have tested when a timing solution is found. If confirmed, the highest spin frequency NSs do not pulse simply because their B fields are too low.

Jonathan E. Grindlay

2006-05-04T23:59:59.000Z

148

Spin Rotation of Formalism for Spin Tracking  

SciTech Connect

The problem of which coefficients are adequate to correctly represent the spin rotation in vector spin tracking for polarized proton and deuteron beams in synchrotrons is here re-examined in the light of recent discussions. The main aim of this note is to show where some previous erroneous results originated and how to code spin rotation in a tracking code. Some analysis of a recent experiment is presented that confirm the correctness of the assumptions.

Luccio,A.

2008-02-01T23:59:59.000Z

149

Examination of Gravity Waves Associated with the 13 March 2003 Bow Echo  

Science Conference Proceedings (OSTI)

Numerical simulations of the 13 March 2003 bow echo over Oklahoma are used to evaluate bow echo development and its relationship with gravity wave generation. Multiple fast-moving (with speeds of 30–35 m s?1) gravity waves are generated in ...

Rebecca D. Adams-Selin; Richard H. Johnson

2013-11-01T23:59:59.000Z

150

Examination of gravity waves associated with 13 March 2003 bow echo  

Science Conference Proceedings (OSTI)

Numerical simulations of the 13 March 2003 bow echo over Oklahoma are used to evaluate bow echo development and its relationship with gravity wave generation. Multiple fast-moving (with speeds of 30-35 m s?1) gravity waves are generated in ...

Rebecca D. Adams-Selin; Richard H. Johnson

151

2007 Special Issue: Automatic speech recognition using a predictive echo state network classifier  

Science Conference Proceedings (OSTI)

We have combined an echo state network (ESN) with a competitive state machine framework to create a classification engine called the predictive ESN classifier. We derive the expressions for training the predictive ESN classifier and show that the model ... Keywords: Automatic speech recognition, Echo state network, Mixture of experts, Noise robustness

Mark D. Skowronski; John G. Harris

2007-04-01T23:59:59.000Z

152

Thermal neutron detection system  

DOE Patents (OSTI)

According to the present invention, a system for measuring a thermal neutron emission from a neutron source, has a reflector/moderator proximate the neutron source that reflects and moderates neutrons from the neutron source. The reflector/moderator further directs thermal neutrons toward an unmoderated thermal neutron detector.

Peurrung, Anthony J. (Richland, WA); Stromswold, David C. (West Richland, WA)

2000-01-01T23:59:59.000Z

153

NEUTRONIC REACTORS  

DOE Patents (OSTI)

A nuclear reactor is described wherein horizontal rods of thermal- neutron-fissionable material are disposed in a body of heavy water and extend through and are supported by spaced parallel walls of graphite.

Wigner, E.P.

1960-11-22T23:59:59.000Z

154

NEUTRONIC REACTOR  

DOE Patents (OSTI)

A neutronic reactor in which neutron moderation is achieved primarily in its reflector is described. The reactor structure consists of a cylindrical central "island" of moderator and a spherical moderating reflector spaced therefrom, thereby providing an annular space. An essentially unmoderated liquid fuel is continuously passed through the annular space and undergoes fission while contained therein. The reactor, because of its small size, is particularly adapted for propulsion uses, including the propulsion of aircraft. (AEC)

Fraas, A.P.; Mills, C.B.

1961-11-21T23:59:59.000Z

155

NEUTRON SOURCES  

DOE Patents (OSTI)

A neutron source is obtained without employing any separate beryllia receptacle, as was formerly required. The new method is safer and faster, and affords a source with both improved yield and symmetry of neutron emission. A Be container is used to hold and react with Pu. This container has a thin isolating layer that does not obstruct the desired Pu--Be reaction and obviates procedures previously employed to disassemble and remove a beryllia receptacle. (AEC)

Richmond, J.L.; Wells, C.E.

1963-01-15T23:59:59.000Z

156

Neutron range spectrometer  

DOE Patents (OSTI)

A neutron range spectrometer and method for determining the neutron energy spectrum of a neutron emitting source are disclosed. Neutrons from the source are colliminated along a collimation axis and a position sensitive neutron counter is disposed in the path of the collimated neutron beam. The counter determines positions along the collimation axis of interactions between the neutrons in the neutron beam and a neutron-absorbing material in the counter. From the interaction positions, a computer analyzes the data and determines the neutron energy spectrum of the neutron beam. The counter is preferably shielded and a suitable neutron-absorbing material is He-3. 1 fig.

Manglos, S.H.

1988-03-10T23:59:59.000Z

157

ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

ORNL's Neutron Science Future: Integrating Neutron Scattering Across the Laboratory Greg Smith, HFIR Center for Neutron Scattering Upgrade Status and Scientific Opportunities...

158

High-Frequency QPOs as a Product of Inner Disk Dynamics around Neutron Stars  

SciTech Connect

The kHz QPOs observed in a neutron star low mass X-ray binary are likely to be produced in the innermost regions of accretion disk around the neutron star. The rotational dynamics of the inner disk can be characterized by the presence of either sub-Keplerian or super-Keplerian accretion flow depending on the relative fastness of the neutron spin as compared to the Keplerian frequency at the inner disk radius. Within the magnetosphere-disk interaction model, the frequency difference between the two kHz QPOs observed in a given source can be estimated to be slightly higher than or nearly around the neutron star spin frequency if the neutron star is a slow rotator and less than the stellar spin frequency if the neutron star is a fast rotator.

Hakan Erkut, M. [Physics Department, Istanbul Kueltuer University, Atakoey Campus, Bakirkoey 34156, Istanbul (Turkey)

2011-09-21T23:59:59.000Z

159

NEUTRONIC REACTOR  

DOE Patents (OSTI)

A nuclear reactor for isotope production is described. This reactor is designed to provide a maximum thermal neutron flux in a region adjacent to the periphery of the reactor rather than in the center of the reactor. The core of the reactor is generally centrally located with respect tn a surrounding first reflector, constructed of beryllium. The beryllium reflector is surrounded by a second reflector, constructed of graphite, which, in tune, is surrounded by a conventional thermal shield. Water is circulated through the core and the reflector and functions both as a moderator and a coolant. In order to produce a greatsr maximum thermal neutron flux adjacent to the periphery of the reactor rather than in the core, the reactor is designed so tbat the ratio of neutron scattering cross section to neutron absorption cross section averaged over all of the materials in the reflector is approximately twice the ratio of neutron scattering cross section to neutron absorption cross section averaged over all of the material of the core of the reactor.

Wigner, E.P.

1958-04-22T23:59:59.000Z

160

Spin Structure with JLab 6 and 12 GeV  

Science Conference Proceedings (OSTI)

Highlights of JLab 6 GeV results on spin structure study and plan for 12 GeV program. Spin structure study is full of surprises and puzzles. A decade of experiments from JLab yield these exciting results: (1) valence spin structure; (2) precision measurements of g{sub 2}/d{sub 2} - high-twist; (3) spin sum rules and polarizabilities; and (4) first neutron transversity. There is a bright future as the 12 GeV Upgrade will greatly enhance our capability: (1) Precision determination of the valence quark spin structure flavor separation; (2) Precision measurements of g{sub 2}/d{sub 2}; and (3) Precision extraction of transversity/tensor charge.

Jian-Ping Chen

2012-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

A new class of adaptive algorithm based on correlation functions for double-talk acoustic echo cancelling  

Science Conference Proceedings (OSTI)

Echo path estimation in echo cancelling for teleconference system is a problem in double talk condition. The correlation processing algorithm was defined by the authors to solve this problem. In this paper, a new fast implementation in the frequency ... Keywords: correlation algorithm, double talk, echo cancelling, frequency domain

Mohammad Reza Asharif; Rui Chen; Katsumi Yamashita

2004-05-01T23:59:59.000Z

162

Magnetodynamics and Spin Electronics  

Science Conference Proceedings (OSTI)

... Spintronics exploits the interaction between electrons' spin angular momentum ... stochastic processes in the form of electron microscope images of ...

2013-05-13T23:59:59.000Z

163

Neutron Repulsion  

E-Print Network (OSTI)

Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch that locked together these puzzling space-age observations: 1.) Excess 136Xe accompanied primordial helium in the stellar debris that formed the solar system (Fig. 1); 2.) The Sun formed on the supernova core (Fig. 2); 3.) Waste products from the core pass through an iron-rich mantle, selectively carrying lighter elements and lighter isotopes of each element into the photosphere (Figs. 3-4); and 4.) Neutron repulsion powers the Sun and sustains life (Figs. 5-7). Together these findings offer a framework for understanding how: a.) The Sun generates and releases neutrinos, energy and solar-wind hydrogen and helium; b.) An inhabitable planet formed and life evolved around an ordinary-looking star; c.) Continuous climate change - induced by cyclic changes in gravitational interactions of the Sun's energetic core with planets - has favored survival by adaptation.

Oliver K. Manuel

2011-02-08T23:59:59.000Z

164

Californium Neutron Irradiation Facility  

Science Conference Proceedings (OSTI)

Californium Neutron Irradiation Facility. Summary: ... Cf irradiation facility (Photograph by: Neutron Physics Group). Lead Organizational Unit: pml. Staff: ...

2013-07-23T23:59:59.000Z

165

Neutron Physics Group  

Science Conference Proceedings (OSTI)

... spectrum and fluencies is essential for several ... Neutron Interferometer and Optics Facility performed a ... other neutron scattering facilities depends on ...

2011-10-24T23:59:59.000Z

166

Cold Neutron and Ultracold Neutron Sources  

Science Conference Proceedings (OSTI)

... Moderators • Solid Methane – CH 4 – CD 4 ... In a cold neutron flux with a continuous spectrum, more neutrons could ... Magneto-vibrational Scatt. + ...

2009-07-13T23:59:59.000Z

167

Chapter 13 - NEUTRON AREA DETECTORS 1. NEUTRON ...  

Science Conference Proceedings (OSTI)

... The neutron peak corresponds to both reaction products being entirely absorbed in the ... 6. A fission chamber is a very low efficiency neutron detector ...

2009-11-29T23:59:59.000Z

168

Geometric phases in electric dipole searches with spin-1/2 particles from spin dependent Schrödinger equation  

E-Print Network (OSTI)

Geometric phases of trapped particles have been recognized as potential sources of false signals in experiments searching for a permanent electric dipole moment of the neutron. We present a new analysis that treats the spin fully quantum mechanically and uses the same model system as previous works based on semi-classical methods. The results are similar but exhibit significant differences in some respects.

A. Steyerl; C. Kaufman; G. Müller; S. S. Malik; A. M. Desai

2013-07-17T23:59:59.000Z

169

Sensing remote nuclear spins  

E-Print Network (OSTI)

Sensing single nuclear spins is a central challenge in magnetic resonance based imaging techniques. Although different methods and especially diamond defect based sensing and imaging techniques in principle have shown sufficient sensitivity, signals from single nuclear spins are usually too weak to be distinguished from background noise. Here, we present the detection and identification of remote single C-13 nuclear spins embedded in nuclear spin baths surrounding a single electron spins of a nitrogen-vacancy centre in diamond. With dynamical decoupling control of the centre electron spin, the weak magnetic field ~10 nT from a single nuclear spin located ~3 nm from the centre with hyperfine coupling as weak as ~500 Hz is amplified and detected. The quantum nature of the coupling is confirmed and precise position and the vector components of the nuclear field are determined. Given the distance over which nuclear magnetic fields can be detected the technique marks a firm step towards imaging, detecting and cont...

Zhao, Nan; Schmid, Berhard; Isoya, Junichi; Markham, Mathew; Twitchen, Daniel; Jelezko, Fedor; Liu, Ren-Bao; Fedder, Helmut; Wrachtrup, Jörg

2012-01-01T23:59:59.000Z

170

NEUTRONIC REACTOR  

DOE Patents (OSTI)

A nuclear reactor which uses uranium in the form of elongated tubes as fuel elements and liquid as a coolant is described. Elongated tubular uranium bodies are vertically disposed in an efficient neutron slowing agent, such as graphite, for example, to form a lattice structure which is disposed between upper and lower coolant tanks. Fluid coolant tubes extend through the uranium bodies and communicate with the upper and lower tanks and serve to convey the coolant through the uranium body. The reactor is also provided with means for circulating the cooling fluid through the coolant tanks and coolant tubes, suitable neutron and gnmma ray shields, and control means.

Wigner, E.P.; Weinberg, A.W.; Young, G.J.

1958-04-15T23:59:59.000Z

171

Study of gamma cascades of 59Ni by thermal neutron reaction  

E-Print Network (OSTI)

The quantum properties are important to study nuclear structure. The energy, spin, parity, transition order are usually interesting to research. In this experiment, 59Ni is activated by thermal neutron on 3rd horizontal channel of Dalat nuclear Reactor.

Nguyen An Son

2013-10-07T23:59:59.000Z

172

NEUTRONIC REACTORS  

DOE Patents (OSTI)

The design of control rods for nuclear reactors are described. In this design the control rod consists essentially of an elongated member constructed in part of a neutron absorbing material and having tube means extending therethrough for conducting a liquid to cool the rod when in use.

Anderson, H.L.

1958-10-01T23:59:59.000Z

173

ON THE INTERPRETATION OF SUPERNOVA LIGHT ECHO PROFILES AND SPECTRA  

Science Conference Proceedings (OSTI)

The light echo (LE) systems of historical supernovae in the Milky Way and local group galaxies provide an unprecedented opportunity to reveal the effects of asymmetry on observables, particularly optical spectra. Scattering dust at different locations on the LE ellipsoid witnesses the supernova from different perspectives, and the light consequently scattered toward Earth preserves the shape of line profile variations introduced by asymmetries in the supernova photosphere. However, the interpretation of supernova LE spectra to date has not involved a detailed consideration of the effects of outburst duration and geometrical scattering modifications due to finite scattering dust filament dimension, inclination, and image point-spread function and spectrograph slit width. In this paper, we explore the implications of these factors and present a framework for future-resolved supernova LE spectra interpretation, and test it against Cas A and SN 1987A LE spectra. We conclude that the full modeling of the dimensions and orientation of the scattering dust using the observed LEs at two or more epochs is critical for the correct interpretation of LE spectra. Indeed, without doing so one might falsely conclude that differences exist when none are actually present.

Rest, A.; Narayan, G. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Sinnott, B.; Welch, D. L. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada); R. J. Foley; Mandel, K. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Huber, M. E. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, 3400 North Charles Street, MD 21218 (United States); Blondin, S., E-mail: arest@stsci.edu [Centre de Physique des Particules de Marseille (CPPM), Aix-Marseille Universite, CNRS/IN2P3, 163 avenue de Luminy, 13288 Marseille Cedex 9 (France)

2011-05-01T23:59:59.000Z

174

Reflections on Reflexions: I. Light Echoes in Type Ia Supernovae  

E-Print Network (OSTI)

In the last ten years, observational evidences about a possible connection between Type Ia Supernovae (SNe) properties and the environment where they explode have been steadily growing. In this paper I discuss, from a theoretical point of view but with an observer's perspective, the usage of light echoes (LEs) to probe the CSM around SNe of Type Ia since, in principle, they give us a unique opportunity of getting a three-dimensional description of the SN environment. In turn, this can be used to check the often suggested association of some Ia's with dusty/star forming regions, which would point to a young population for the progenitors. After giving a brief introduction to the LE phenomenon in single scattering approximation, I derive analytical and numerical solutions for the optical light and colour curves for a few simple dust geometries. A fully 3D multiple scattering treatment has also been implemented in a Monte Carlo code, which I have used to investigate the effects of multiple scattering. In particu...

Patat, F

2004-01-01T23:59:59.000Z

175

SmartPower Spreading Energy Efficiency to Echo-boomers | Department of  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

SmartPower Spreading Energy Efficiency to Echo-boomers SmartPower Spreading Energy Efficiency to Echo-boomers SmartPower Spreading Energy Efficiency to Echo-boomers April 9, 2010 - 4:36pm Addthis Paul Lester Communications Specialist, Office of Energy Efficiency and Renewable Energy What are the key facts? Research shows that once young people start unplugging unused electronic devices, they are likely to take more action to reduce their energy use. Saving energy is cool. That's the message SmartPower is spreading online to 80 million echo-boomers, the generation born between 1982 and 1995. "They are the generation that best appreciates the need for mitigation of climate change," says Jonathan Edwards, vice president of SmartPower, a non-profit that has developed creative Web marketing campaigns aimed at

176

SmartPower Spreading Energy Efficiency to Echo-boomers | Department of  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

SmartPower Spreading Energy Efficiency to Echo-boomers SmartPower Spreading Energy Efficiency to Echo-boomers SmartPower Spreading Energy Efficiency to Echo-boomers April 9, 2010 - 4:36pm Addthis Paul Lester Communications Specialist, Office of Energy Efficiency and Renewable Energy What are the key facts? Research shows that once young people start unplugging unused electronic devices, they are likely to take more action to reduce their energy use. Saving energy is cool. That's the message SmartPower is spreading online to 80 million echo-boomers, the generation born between 1982 and 1995. "They are the generation that best appreciates the need for mitigation of climate change," says Jonathan Edwards, vice president of SmartPower, a non-profit that has developed creative Web marketing campaigns aimed at

177

Microphysical Characteristics of a Well-Developed Weak Echo Region in a High Plains Supercell Thunderstorm  

Science Conference Proceedings (OSTI)

Microphysical measurements in and near the weak echo region of a supercell thunderstorm are discussed. The observations were made in southeastern Montana with an armored T-28 aircraft, which has the capability to measure hydrometeors over almost ...

Dennis J. Musil; Andrew J. Heymsfield; Paul L. Smith

1986-07-01T23:59:59.000Z

178

A Wavelet Transform Technique for Removing Airplane Echoes from ST Radar Signals  

Science Conference Proceedings (OSTI)

This paper presents a new technique based on the wavelet transforms for removing airplane and other transitory echoes in strato–tropospheric (ST) radar measurements. This technique provides a time–frequency display of the time series, which is ...

J-C. Boisse; V. Klaus; J-P. Aubagnac

1999-03-01T23:59:59.000Z

179

Visual Cloud Histories Related to First Radar Echo Formation in Northeast Colorado Cumulus  

Science Conference Proceedings (OSTI)

Using quantitative analysis of time-lapse motion pictures from aircraft and a sensitive meteorological radar, the cloud top history is related to the early radar echo development in 12 vigorous, summer, convective cloud turrets in northeastern ...

Charles A. Knight; William D. Hall; Philip M. Roskowski

1983-06-01T23:59:59.000Z

180

Radar Receiver Calibration by Means of Multiple Processing of Weather Echoes  

Science Conference Proceedings (OSTI)

In this paper we analyze a method of real-time radar receiver calibration by means of multiple processing of the same meteorological echoes collected during the routine measurements.

Eugenio Gorgucci; Gianfranco Scarchilli; Roberto Leonardi

1989-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

First Radar Echoes and the Early ZDR History of Florida Cumulus  

Science Conference Proceedings (OSTI)

The early histories of radar echo and polarization differential reflectivity (ZDR) from growing cumulus clouds observed in Florida with a 10-cm-wavelength radar are reported in detail. Raindrops 1 to several millimeters in diameter are present at ...

Charles A. Knight; Jothiram Vivekanandan; Sonia G. Lasher-Trapp

2002-05-01T23:59:59.000Z

182

Microsoft Word - TR_SiteEcho_Final_R1-V2.doc  

NLE Websites -- All DOE Office Websites (Extended Search)

TOPICAL REPORT: TEST RESULTS FOR A COMBINED CYCLE POWER PLANT WITH OXIDATION CATALYST AND SCR AT SITE ECHO February 2005 CEC-500-2005-042 Revision 1.2 October 26, 2004 ii When...

183

Quantitative Analysis and Interpretation of Dot Echoes Observed with a Doppler Sodar  

Science Conference Proceedings (OSTI)

While some people involved in the acoustic remote sensing field are aware of the possibility of receiving dot echoes from nonatmospheric targets, most of the papers available in the scientific literature dealing with this phenomenon associate ...

G. Mastrantonio; J. Naithani; P. S. Anderson; S. Argentini; I. Petenko

1999-12-01T23:59:59.000Z

184

Correction of Amplitudes of Bragg Lines in the Sea Echo Doppler Spectrum of an Ocean Radar  

Science Conference Proceedings (OSTI)

Amplitudes of Bragg lines in the Doppler spectrum of high frequency or very high frequency (VHF) ocean radar sea echoes are important because they are used in normalizing the second-order scattering when calculating ocean wave spectra. These ...

Yukiharu Hisaki

1999-10-01T23:59:59.000Z

185

Characteristics of Rainbands, Radar Echoes, and Lightning near the North Carolina Coast during GALE  

Science Conference Proceedings (OSTI)

Characteristics of mesoscale rainbands and echoes in radar reflectivity data recorded during the field phase of the Genesis of Atlantic Lows Experiment (GALE) are presented. The primary sources of data were radar microfilm and manually digitized ...

Peter P. Dodge; Robert W. Burpee

1993-07-01T23:59:59.000Z

186

Monitoring Gulf Stream Transport by Radar Altimeter and Inverted Echo Sounders  

Science Conference Proceedings (OSTI)

Profiles of the Gulf Stream sea surface height (SSH) from the Geosat altimeter were compared with thermocline depth measurements from inverted echo sounders (IES) for a period of about 19 months. The correlation between SSH anomalies and ...

Kathryn A. Kelly; D. Randolph Watts

1994-05-01T23:59:59.000Z

187

The Processing and Application of Inverted Echo Sounder Data from Drake Passage  

Science Conference Proceedings (OSTI)

Bottom pressure recorders (BPRs) have been deployed at Drake Passage (DP) to monitor changes in the volume transport of the Antarctic Circumpolar Current (ACC) through the passage. The use of inverted echo sounders (IESs) in assisting the ...

Michael P. Meredith; John M. Vassie; Robert Spencer; Karen J. Heywood

1997-08-01T23:59:59.000Z

188

Methods for absorbing neutrons  

DOE Patents (OSTI)

A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

Guillen, Donna P. (Idaho Falls, ID); Longhurst, Glen R. (Idaho Falls, ID); Porter, Douglas L. (Idaho Falls, ID); Parry, James R. (Idaho Falls, ID)

2012-07-24T23:59:59.000Z

189

Neutron reflecting supermirror structure  

DOE Patents (OSTI)

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources.

Wood, James L. (Drayton Plains, MI)

1992-01-01T23:59:59.000Z

190

Neutron reflecting supermirror structure  

DOE Patents (OSTI)

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. 2 figs.

Wood, J.L.

1992-12-01T23:59:59.000Z

191

Spin coating apparatus  

DOE Patents (OSTI)

A spin coating apparatus requires less cleanroom air flow than prior spin coating apparatus to minimize cleanroom contamination. A shaped exhaust duct from the spin coater maintains process quality while requiring reduced cleanroom air flow. The exhaust duct can decrease in cross section as it extends from the wafer, minimizing eddy formation. The exhaust duct can conform to entrainment streamlines to minimize eddy formation and reduce interprocess contamination at minimal cleanroom air flow rates.

Torczynski, John R. (Albuquerque, NM)

2000-01-01T23:59:59.000Z

192

Neutron Scattering Facilities 1982  

NLE Websites -- All DOE Office Websites (Extended Search)

NEUTRON SOURCES NEUTRON SOURCES Types of Sources U.S. Sources Available for Users Plans for the Future The Neutron Scattering Society of America (NSSA) SNS/ANL School on Neutron and x-Ray Scattering, June 2011 Jim Rhyne Lujan Neutron Scattering Center Los Alamos National Lab. What do we need to do neutron scattering? * Neutron Source - produces neutrons * Diffractometer or Spectrometer - Allows neutrons to interact with sample - Sorts out discrete wavelengths by monochromator (reactor) or by time of flight (pulse source) - Detectors pick up neutrons scattered from sample * Analysis methods to determine material properties * Brain power to interpret results Sources of neutrons for scattering * Nuclear Reactor - Neutrons produced from fission of 235 U - Fission spectrum neutrons

193

Fermi Liquid Instabilities in the Spin Channel  

SciTech Connect

We study the Fermi surface instabilities of the Pomeranchuk type in the spin triplet channel with high orbital partial waves (F{sub l}{sup a} (l > 0)). The ordered phases are classified into two classes, dubbed the {alpha} and {beta}-phases by analogy to the superfluid {sup 3}He-A and B-phases. The Fermi surfaces in the {alpha}-phases exhibit spontaneous anisotropic distortions, while those in the {beta}-phases remain circular or spherical with topologically non-trivial spin configurations in momentum space. In the {alpha}-phase, the Goldstone modes in the density channel exhibit anisotropic overdamping. The Goldstone modes in the spin channel have nearly isotropic underdamped dispersion relation at small propagating wavevectors. Due to the coupling to the Goldstone modes, the spin wave spectrum develops resonance peaks in both the {alpha} and {beta}-phases, which can be detected in inelastic neutron scattering experiments. In the p-wave channel {beta}-phase, a chiral ground state inhomogeneity is spontaneously generated due to a Lifshitz-like instability in the originally nonchiral systems. Possible experiments to detect these phases are discussed.

Wu, Congjun; /Santa Barbara, KITP; Sun, Kai; Fradkin, Eduardo; /Illinois U., Urbana; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

2010-03-16T23:59:59.000Z

194

Reflections on Reflexions: I. Light Echoes in Type Ia Supernovae  

E-Print Network (OSTI)

In the last ten years, observational evidences about a possible connection between Type Ia Supernovae (SNe) properties and the environment where they explode have been steadily growing. In this paper I discuss, from a theoretical point of view but with an observer's perspective, the usage of light echoes (LEs) to probe the CSM around SNe of Type Ia since, in principle, they give us a unique opportunity of getting a three-dimensional description of the SN environment. In turn, this can be used to check the often suggested association of some Ia's with dusty/star forming regions, which would point to a young population for the progenitors. After giving a brief introduction to the LE phenomenon in single scattering approximation, I derive analytical and numerical solutions for the optical light and colour curves for a few simple dust geometries. A fully 3D multiple scattering treatment has also been implemented in a Monte Carlo code, which I have used to investigate the effects of multiple scattering. In particular, I have explored in detail the LE colour dependency from time and dust distribution, since this is a promising tool to determine the dust density and derive the effective presence of multiple scattering from the observed properties. Finally, again by means of Monte Carlo simulations, I have studied the effects of multiple scattering on the LE linear polarization, analyzing the dependencies from the dust parameters and geometry. Both the analytical formalism and MC codes described in this paper can be used for any LE for which the light curve of the central source is known.

F. Patat

2004-09-28T23:59:59.000Z

195

Spin coating of electrolytes  

DOE Patents (OSTI)

Methods for spin coating electrolytic materials onto substrates are disclosed. More particularly, methods for depositing solid coatings of ion-conducting material onto planar substrates and onto electrodes are disclosed. These spin coating methods are employed to fabricate electrochemical sensors for use in measuring, detecting and quantifying gases and liquids.

Stetter, Joseph R. (Naperville, IL); Maclay, G. Jordan (Maywood, IL)

1989-01-01T23:59:59.000Z

196

Quantum Spin Systems  

E-Print Network (OSTI)

This article is a short introduction to the general topic of quantum spin systems. After a brief sketch of the history of the subject, the standard mathematical framework for formulating problems and results in quantum spin systems is described. Then, three short sections are devoted to Spontaneaous Symmetry Breaking, Phase transitions, and Dynamcis.

Bruno Nachtergaele

2004-09-02T23:59:59.000Z

197

NEUTRINO PROCESSES IN PARTIALLY DEGENERATE NEUTRON MATTER  

Science Conference Proceedings (OSTI)

We investigate neutrino processes for conditions reached in simulations of core-collapse supernovae. In regions where neutrino-matter interactions play an important role, matter is partially degenerate, and we extend earlier work that addressed the degenerate regime. We derive expressions for the spin structure factor in neutron matter, which is a key quantity required for evaluating rates of neutrino processes. We show that, for essentially all conditions encountered in the post-bounce phase of core-collapse supernovae, it is a very good approximation to calculate the spin relaxation rates in the nondegenerate limit. We calculate spin relaxation rates based on chiral effective field theory interactions and find that they are typically a factor of two smaller than those obtained using the standard one-pion-exchange interaction alone.

Bacca, S.; Hally, K. [TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3 (Canada); Liebendoerfer, M.; Perego, A. [Department of Physics, University of Basel, Klingelbergstr. 82, 4056 Basel (Switzerland); Pethick, C. J. [Niels Bohr International Academy, Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen O (Denmark); Schwenk, A. [ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, D-64291 Darmstadt (Germany)

2012-10-10T23:59:59.000Z

198

On the spin-up/spin-down transitions in accreting X-ray binaries  

E-Print Network (OSTI)

Accreting X-Ray Binaries display a wide range of behaviours. Some of them are observed to spin up steadily, others to alternate between spin-up and spin-down states, sometimes superimposed on a longer trend of either spin up or spin down. Here we interpret this rich phenomenology within a new model of the disk-magnetosphere interaction. Our model, based on the simplest version of a purely material torque, accounts for the fact that, when a neutron star is in the propeller regime, a fraction of the ejected material does not receive enough energy to completely unbind, and hence falls back into the disk. We show that the presence of this feedback mass component causes the occurrence of multiple states available to the system, for a given, constant value of the mass accretion rate dot{M}_* from the companion star. If the angle chi of the magnetic dipole axis with respect to the perpendicular to the disk is larger than a critical value chi_crit, the system eventually settles in a cycle of spin-up/spin-down transitions for a constant value of dot{M}_* and independent of the initial conditions. No external perturbations are required to induce the torque reversals. The transition from spin up to spin down is often accompanied by a large drop in luminosity. The frequency range spanned in each cycle and the timescale for torque reversals depend on dot{M}_*, the magnetic field of the star, the magnetic colatitude chi, and the degree of elasticity regulating the magnetosphere-disk interaction. The critical angle chi_crit ranges from \\~25-30 deg for a completely elastic interaction to ~40-45 deg for a totally anelastic one. For chi ~< chi_crit, cycles are no longer possible and the long-term evolution of the system is a pure spin up. We specifically illustrate our model in the cases of the X-ray binaries GX 1+4 and 4U 1626-67.

Rosalba Perna; Enrico Bozzo; Luigi Stella

2005-11-09T23:59:59.000Z

199

Contact ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Sciences Organization Charts Neutron Sciences Directorate Associate Laboratory Director for Neutron Sciences, Kelly Beierschmitt Biology and Soft Matter Division Director, Paul...

200

Neutron Compound Refractive Prisms - DOE SBIR Phase II Final Report  

SciTech Connect

The results of the research led to a pulsed electromagnetic periodic magnetic field array (PMF), which coupled with a pair of collimation slits, and a mechanical chopper slit, were able to deflect spin-up neutrons to a band of line-fused neutrons a focal plane heights that correspond to the time-varying magnetic field amplitude. The electromagnetic field PMF produced 5.4 pulses per minute in which each pulse was 50 msec in duration with a full width half maximum (FWHM) of 7.5 msec. The calculated 7.7 mm vertical height of the band of focused spin-up neutrons corresponded closely to the measured 7.5 mm height of the center line of the imaged band of neutrons. The band of deflected spin-up neutrons was 5 mm in vertical width and the bottom of the band was 5 mm above the surface of the PMF pole. The limited exposure time of 3 hours and the smaller 0.78 T magnetic field allowed focused and near focused neutrons of 1.8 ���� to 2.6 ���� neutrons, which were in the tails of the McClellan Nuclear Radiation Center Bay 4 Maxwell Boltzmann distribution of neutrons with peak flux at 1.1-1.2 ����. The electromagnetic PMF was expected to produces a 2.0 T peak magnetic field amplitude, which would be operational at a higher duty factor, rather than the as built 7.5 msec FWHM with pulse repetition frequency of 5.4 pulses per minute. The fabricated pulsed electromagnetic PMF with chopper is expected to perform well on a cold, very cold or ultra cold beam line as a spectrometer or monochromator source of spin-up polarized neutron. In fact there may be a possible use of the PMF to do ultra-cold neutron trapping, see paper by A. I. Frank1, V. G. Nosov, Quantum Effects in a One-Dimensional Magnetic Gravitational Trap for Ultracold Neutrons, JETP Letters, Vol. 79, No. 7, 2004, pp. 313�¢����315. The next step is to find a cold or very cold neutron facility, where further testing or use of the pulsed magnetic field PMF can be pursued.

Dr. Jay Theodore Cremer, Jr

2011-06-25T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

NEUTRON SOURCE  

DOE Patents (OSTI)

A neutron source of the antimony--beryllium type is presented. The source is comprised of a solid mass of beryllium having a cylindrical recess extending therein and a cylinder containing antimony-124 slidably disposed within the cylindrical recess. The antimony cylinder is encased in aluminum. A berylliunn plug is removably inserted in the open end of the cylindrical recess to completely enclose the antimony cylinder in bsryllium. The plug and antimony cylinder are each provided with a stud on their upper ends to facilitate handling remotely.

Reardon, W.A.; Lennox, D.H.; Nobles, R.G.

1959-01-13T23:59:59.000Z

202

Neutrino signatures and the neutrino-driven wind in Binary Neutron Star Mergers  

E-Print Network (OSTI)

We present VULCAN/2D multi-group flux-limited-diffusion radiation hydrodynamics simulations of binary neutron star (BNS) mergers, using the Shen equation of state, covering ~100 ms, and starting from azimuthal-averaged 2D slices obtained from 3D SPH simulations of Rosswog & Price for 1.4 Msun (baryonic) neutron stars with no initial spins, co-rotating spins, and counter-rotating spins. Snapshots are post-processed at 10 ms intervals with a multi-angle neutrino-transport solver. We find polar-enhanced neutrino luminosities, dominated by $\\bar{\

Luc Dessart; Christian Ott; Adam Burrows; Stefan Rosswog; Eli Livne

2008-06-26T23:59:59.000Z

203

Neutrino signatures and the neutrino-driven wind in Binary Neutron Star Mergers  

E-Print Network (OSTI)

We present VULCAN/2D multi-group flux-limited-diffusion radiation hydrodynamics simulations of binary neutron star (BNS) mergers, using the Shen equation of state, covering ~100 ms, and starting from azimuthal-averaged 2D slices obtained from 3D SPH simulations of Rosswog & Price for 1.4 Msun (baryonic) neutron stars with no initial spins, co-rotating spins, and counter-rotating spins. Snapshots are post-processed at 10 ms intervals with a multi-angle neutrino-transport solver. We find polar-enhanced neutrino luminosities, dominated by $\\bar{\

Dessart, Luc; Burrows, Adam; Rosswog, Stefan; Livne, Eli

2008-01-01T23:59:59.000Z

204

Spallation Neutron Source | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Spallation Neutron Source SNS site, Spring 2012 The 80-acre SNS site is located on the east end of the ORNL campus and is about a three-minute drive from her sister neutron...

205

Science | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Science Neutron Science Neutron Scattering Science Neutrons are one of the fundamental particles that make up matter and have properties that make them ideal for certain types of research. In the universe, neutrons are abundant, making up more than half of all visible matter. Neutron scattering provides information about the positions, motions, and magnetic properties of solids. When a beam of neutrons is aimed at a sample, many neutrons will pass through the material. But some will interact directly with atomic nuclei and "bounce" away at an angle, like colliding balls in a game of pool. This behavior is called neutron diffraction, or neutron scattering. Using detectors, scientists can count scattered neutrons, measure their energies and the angles at which they scatter, and map their final position

206

PHYSICAL REVIEW A VOLUME 42, NUMBER 3 Light-shift-induced spin echoes in a J =t  

E-Print Network (OSTI)

between the two magnetic substates of the ground state corresponding to a magnetization along the laser atomic ground state M. Rosatzin, D. Suter, and J. Mlynek* Institute of Quantum Electronics, Swiss Federal on the *S1/2 sodium ground state are in good qualitative agreement with theoretical predictions. Coherent

Suter, Dieter

207

Spinning fluid cosmology  

E-Print Network (OSTI)

The dynamics of a spinning fluid in a flat cosmological model is investigated. The space-time is itself generated by the spinning fluid which is characterized by an energy-momentum tensor consisting a sum of the usual perfect-fluid energy-momentum tensor and some Belinfante-Rosenfeld tensors. It is shown that the equations of motion admit a solution for which the fluid four-velocity and four-momentum are not co-linear in general. The momentum and spin densities of the fluid are expressed in terms of the scale factor.

Morteza Mohseni

2008-07-22T23:59:59.000Z

208

Spinning fluid cosmology  

E-Print Network (OSTI)

The dynamics of a spinning fluid in a flat cosmological model is investigated. The space-time is itself generated by the spinning fluid which is characterized by an energy-momentum tensor consisting a sum of the usual perfect-fluid energy-momentum tensor and some Belinfante-Rosenfeld tensors. It is shown that the equations of motion admit a solution for which the fluid four-velocity and four-momentum are not co-linear in general. The momentum and spin densities of the fluid are expressed in terms of the scale factor.

Mohseni, Morteza

2008-01-01T23:59:59.000Z

209

Spin Modes in Nuclei and Nuclear Forces  

SciTech Connect

Spin modes in stable and unstable exotic nuclei are studied and important roles of tensor and three-body forces on nuclear structure are discussed. New shell model Hamiltonians, which have proper tensor components, are shown to explain shell evolutions toward drip-lines and spin properties of both stable and exotic nuclei, for example, Gamow-Teller transitions in {sup 12}C and {sup 14}C and an anomalous M1 transition in {sup 17}C. The importance and the necessity of the repulsive monopole corrections in isospin T = 1 channel to the microscopic two-body interactions are pointed out. The corrections are shown to lead to the proper shell evolutions in neutron-rich isotopes. The three-body force, in particular the Fujita-Miyazawa force induced by {Delta} excitations, is pointed out to be responsible for the repulsive corrections among the valence neutrons. The important roles of the three-body force on the energies and transitions in exotic oxygen and calcium isotopes are demonstrated.

Suzuki, Toshio [Department of Physics and Graduate School of Integrated Basic Sciences, College of Humanities and Sciences, Nihon University, Sakurajosui 3-25-40, Setagaya-ku, Tokyo 156-8550 (Japan) and Center for Nuclear Study, University of Tokyo, Hirosawa, Wako-shi, Saitama, 351-0198 (Japan); Otsuka, Takaharu [Department of Physics and Center for Nuclear Study, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2011-05-06T23:59:59.000Z

210

ORNL neutron facilities deliver neutrons  

Science Conference Proceedings (OSTI)

The High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) resumed full power operations on May 16, 2007. There were three experiment cycles of 23 to 25 days in FY2007 and another six are proposed for FY2008 beginning in November 2007. During FY 2007, the High Flux Isotope Reactor delivered 1178 operating hours to users. Commissioning of two SANS instruments is under way and these instruments will join the user program in 2008. The Neutron Scattering Science Advisory Committee endorsed language encouraging development of the science case for two instruments proposed for HFIR.

Ekkebus, Allen E [ORNL

2008-01-01T23:59:59.000Z

211

Measurement of the neutron magnetic form factor from inclusive quasielastic scattering of polarized electrons from polarized [sup 3]He  

SciTech Connect

We report a measurement of the asymmetry in spin-dependent quasielastic scattering of longitudinally polarized electrons from a polarized [sup 3]He target. The neutron magnetic form factor [ital G][sup [ital n

Gao, H.; Arrington, J.; Beise, E.J.; Bray, B.; Carr, R.W.; Filippone, B.W.; Lung, A.; McKeown, R.D.; Mueller, B.; Pitt, M.L. (California Institute of Technology, Pasadena, California 91125 (United States)); Jones, C.E. (Argonne National Laboratory, Argonne, Illinois 60439 (United States)); DeSchepper, D.; Dodson, G.; Dow, K.; Ent, R.; Farkhondeh, M.; Hansen, J.; Korsch, W.; Kramer, L.H.; Lee, K.; Makins, N.; Milner, R.G.; Tieger, D.R.; Welch, T.P. (Bates Linear Accelerator Center, Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, Masschusetts 02139 (United States)); Candell, E.; Napolitano, J.; Wojtsekhowski, B.B.; Tripp, C. (Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)); Lorenzon, W. (TRIUMF, Vancouver, British Columbia, V6T 2A3 (Canada))

1994-08-01T23:59:59.000Z

212

Time reversal invariance in polarized neutron decay  

SciTech Connect

An experiment to measure the time reversal invariance violating (T-violating) triple correlation (D) in the decay of free polarized neutrons has been developed. The detector design incorporates a detector geometry that provides a significant improvement in the sensitivity over that used in the most sensitive of previous experiments. A prototype detector was tested in measurements with a cold neutron beam. Data resulting from the tests are presented. A detailed calculation of systematic effects has been performed and new diagnostic techniques that allow these effects to be measured have been developed. As the result of this work, a new experiment is under way that will improve the sensitivity to D to 3 {times} 10{sup {minus}4} or better. With higher neutron flux a statistical sensitivity of the order 3 {times} 10{sup {minus}5} is ultimately expected. The decay of free polarized neutrons (n {yields} p + e + {bar v}{sub e}) is used to search for T-violation by measuring the triple correlation of the neutron spin polarization, and the electron and proton momenta ({sigma}{sub n} {center_dot} p{sub p} {times} p{sub e}). This correlation changes sign under reversal of the motion. Since final state effects in neutron decay are small, a nonzero coefficient, D, of this correlation indicates the violation of time reversal invariance. D is measured by comparing the numbers of coincidences in electron and proton detectors arranged symmetrically about a longitudinally polarized neutron beam. Particular care must be taken to eliminate residual asymmetries in the detectors or beam as these can lead to significant false effects. The Standard Model predicts negligible T-violating effects in neutron decay. Extensions to the Standard Model include new interactions some of which include CP-violating components. Some of these make first order contributions to D.

Wasserman, E.G.

1994-03-01T23:59:59.000Z

213

Cerenkov radiation of spinning particle  

E-Print Network (OSTI)

The Cerenkov radiation of a neutral particle with magnetic moment is considered, as well as the spin-dependent contribution to the Cerenkov radiation of a charged spinning particle. The corresponding radiation intensity is obtained for an arbitrary value of spin and for an arbitrary spin orientation with respect to velocity.

I. B. Khriplovich

2008-08-11T23:59:59.000Z

214

Recent Results of Target Single-Spin Asymmetry Experiments at Jefferson Lab  

SciTech Connect

We report recent results from Jefferson Lab Hall A “Neutron Transversity” experiment (E06-010). Transversely polarized target single-spin asymmetry AUT and beam-target double-spin asymmetry A{sub LT} have been measured in semi-inclusive deep-inelastic scattering (SIDIS) reactions on a polarized neutron ({sup 3}He) target. Collins-type and Sivers-type asymmetries have been extracted from A{sub UT} for charged pion SIDIS productions, which are sensitive to quark transversity and Sivers distributions, correspondingly. Double spin asymmetry A{sub LT} is sensitive to a specific quark transverse momentum dependent parton distribution (TMD), the so-called “ transverse helicity” (g{sub 1T} ) distributions. In addition, target single-spin asymmetries A{sub y} in inclusive electron scattering on a transversely polarized {sup 3}He target in quasi-elastic and deep inelastic kinematics were also measured in Hall A.

Jiang, Xiaodong [Los Alamos National Lab

2013-08-01T23:59:59.000Z

215

NEUTRONIC REACTORS  

DOE Patents (OSTI)

A method is presented for loading and unloading rod type fuel elements of a neutronic reactor of the heterogeneous, solld moderator, liquid cooled type. In the embodiment illustrated, the fuel rods are disposed in vertical coolant channels in the reactor core. The fuel rods are loaded and unloaded through the upper openings of the channels which are immersed in the coolant liquid, such as water. Unloading is accomplished by means of a coffer dam assembly having an outer sleeve which is placed in sealing relation around the upper opening. A radiation shield sleeve is disposed in and reciprocable through the coffer dam sleeve. A fuel rod engaging member operates through the axial bore in the radiation shield sleeve to withdraw the fuel rod from its position in the reactor coolant channel into the shield, the shield snd rod then being removed. Loading is accomplished in the reverse procedure.

Wigner, E.P.; Young, G.J.

1958-10-14T23:59:59.000Z

216

Neutron reflecting supermirror structure  

DOE Patents (OSTI)

An improved neutron reflecting supermirror structure comprising a plurality of stacked sets of bilayers of neutron reflecting materials. The improved neutron reflecting supermirror structure is adapted to provide extremely good performance at high incidence angles, i.e. up to four time the critical angle of standard neutron mirror structures. The reflection of neutrons striking the supermirror structure at a high critical angle provides enhanced neutron throughput, and hence more efficient and economical use of neutron sources. One layer of each set of bilayers consist of titanium, and the second layer of each set of bilayers consist of an alloy of nickel with carbon interstitially present in the nickel alloy.

Wood, James L. (Drayton Plains, MI)

1992-01-01T23:59:59.000Z

217

Deuteron Spin Structure Functions in the Resonance and DIS Regions  

SciTech Connect

We derive relations between spin-dependent nuclear and nucleon g_1 and g_2 structure functions, valid at all Q^2, and in both the resonance and deep inelastic regions. We apply the formalism to the specific case of the deuteron, which is often used as a source of neutron structure information, and compare the size of the nuclear corrections calculated using exact kinematics and using approximations applicable at large Q^2.

S. Kulagin; W. Melnitchouk

2007-10-03T23:59:59.000Z

218

The Versatile Neutron Imaging Instrument at SNS | ORNL Neutron...  

NLE Websites -- All DOE Office Websites (Extended Search)

The Versatile Neutron Imaging Instrument at SNS VENUS: Neutron imaging to advance energy efficiency VENUS: Neutron imaging to advance energy efficiency. As its name indicates,...

219

Type II superconductivity and magnetic flux transport in neutrons stars  

E-Print Network (OSTI)

The transition to a type II proton superconductor which is believed to occur in a cooling neutron star is accompanied by changes in the equation of hydrostatic equilibrium and by the formation of proton vortices with quantized magnetic flux. Analysis of the electron Boltzmann equation for this system and of the proton supercurrent distribution formed at the transition leads to the derivation of a simple expression for the transport velocity of magnetic flux in the liquid interior of a neutron star. This shows that flux moves easily as a consequence of the interaction between neutron and proton superfluid vortices during intervals of spin-down or spin-up in binary systems. The differences between the present analysis and those of previous workers are reviewed and an error in the paper of Jones (1991) is corrected.

P. B. Jones

2005-10-13T23:59:59.000Z

220

Imaging with Scattered Neutrons  

E-Print Network (OSTI)

We describe a novel experimental technique for neutron imaging with scattered neutrons. These scattered neutrons are of interest for condensed matter physics, because they permit to reveal the local distribution of incoherent and coherent scattering within a sample. In contrast to standard attenuation based imaging, scattered neutron imaging distinguishes between the scattering cross section and the total attenuation cross section including absorption. First successful low-noise millimeter-resolution images by scattered neutron radiography and tomography are presented.

H. Ballhausen; H. Abele; R. Gaehler; M. Trapp; A. Van Overberghe

2006-10-30T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Dimensional crossover in a spin liquid to helimagnet quantum phase transition.  

SciTech Connect

Neutron scattering is used to study magnetic field induced ordering in the quasi-1D quantum spin-tube compound Sul-Cu2Cl4 that in zero field has a non-magnetic spin-liquid ground state. The experiments reveal an incommensurate chiral high-field phase stabilized by a geometric frustration of the magnetic interactions. The measured critical exponents \\beta= 0.235 and \

Garlea, Vasile O [ORNL; Zheludev, Andrey I [ORNL; Habicht, Klaus [Hahn-Meitner Institut, Berlin, Germany; Meissner, Michael [Hahn-Meitner Institut, Berlin, Germany; Grenier, B. [CEA, Grenoble, France; Regnault, L.-P. [CEA, Grenoble, France; Ressouche, E. [CEA, Grenoble, France

2009-01-01T23:59:59.000Z

222

Local quenches in frustrated quantum spin chains: Global versus subsystem equilibration  

SciTech Connect

We study the equilibration behavior following local quenches, using frustrated quantum spin chains as an example of interacting closed quantum systems. Specifically, we examine the statistics of the time series of the Loschmidt echo, the trace distance of the time-evolved local density matrix to its average state, and the local magnetization. Depending on the quench parameters, the equilibration statistics of these quantities show features of good or poor equilibration, indicated by Gaussian, exponential, or bistable distribution functions. These universal functions provide valuable tools to characterize the various time-evolution responses and give insight into the plethora of equilibration phenomena in complex quantum systems.

Diez, Mathias [Department of Physics and Astronomy and Center for Quantum Information Science and Technology, University of Southern California, Los Angeles, California 90089-0484 (United States); Department of Physics, University of Konstanz, D-78457 Konstanz (Germany); Chancellor, Nicholas; Haas, Stephan [Department of Physics and Astronomy and Center for Quantum Information Science and Technology, University of Southern California, Los Angeles, California 90089-0484 (United States); Venuti, Lorenzo Campos [Institute for Scientific Interchange (ISI), Viale S. Severo 65, I-10133 Torino (Italy); Zanardi, Paolo [Department of Physics and Astronomy and Center for Quantum Information Science and Technology, University of Southern California, Los Angeles, California 90089-0484 (United States); Institute for Scientific Interchange (ISI), Viale S. Severo 65, I-10133 Torino (Italy)

2010-09-15T23:59:59.000Z

223

Directorate Organization | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

ORNL Neutron Sciences Directorate The Neutron Sciences Directorate (NScD) manages and operates the Spallation Neutron Source and the High Flux Isotope Reactor, two of the world's...

224

Sum rule measurements of the spin-dependent compton amplitude (nucleon spin structure at Q{sup 2} = 0)  

Science Conference Proceedings (OSTI)

Energy weighted integrals of the difference in helicity-dependent photo-production cross sections ({sigma}{sub {1/2}} - {sigma}{sub 3/2}) provide information on the nucleon`s Spin-dependent Polarizability ({gamma}), and on the spin-dependent part of the asymptotic forward Compton amplitude through the Drell-Hearn-Gerasimov (DHG) sum rule. (The latter forms the Q{sup 2}=0 limit of recent spin-asymmetry experiments in deep-inelastic lepton-scattering.) There are no direct measurements of {sigma}{sub {1/2}} or {sigma}{sub 3/2}, for either the proton or the neutron. Estimates from current {pi}-photo-production multipole analyses, particularly for the proton-neutron difference, are in good agreement with relativistic-l-loop Chiral calculations ({chi}PT) for {gamma} but predict large deviations from the DHG sum rule. Either (a) both the 2-loop corrections to the Spin-Polarizability are large and the existing multipoles are wrong, or (b) modifications to the Drell-Hearn-Gerasimov sum rule are required to fully describe the isospin structure of the nucleon. The helicity-dependent photo-reaction amplitudes, for both the proton and the neutron, will be measured at LEGS from pion-threshold to 470 MeV. In these double-polarization experiments, circularly polarized photons from LEGS will be used with SPHICE, a new frozen-spin target consisting of {rvec H} {center_dot} {rvec D} in the solid phase. Reaction channels will be identified in SASY, a large detector array covering about 80% of 4{pi}. A high degree of symmetry in both target and detector will be used to minimize systematic uncertainties.

Babusci, D.; Giordano, G. [Laboratori Nationali di Frascati-INFN, Rome (Italy); Baghaei, H.; Cichocki, A. [Univ. of Virginia, Charlottesville, VA (United States); Blecher, M. [Virginia Polytechnic Institute and State Univ., Blacksburg, VA (United States); Breuer, M.; Commeaux, C.; Didelez, J.P. [IN2P3, Orsay (France); Caracappa, A. [Brookhaven National Lab., Upton, NY (United States); Fan, Q. [Syracuse Univ., NY (United States)] [and others

1995-12-31T23:59:59.000Z

225

Monitoring of Refractory Wall recession using high temperature impact echo instrumentation  

SciTech Connect

Regression of refractory linings of furnaces occurs due to a variety of mechanisms. The specific mechanism selected for investigation during this program is the regression of refractories which are in direct contact with a liquid corrodant. Examples include the melting of glass, the production of pig iron and steel, and the melting of aluminum. The rates of regression to a wall thickness which requires reline or extensive reconstruction vary widely, from less than a year to over ten years depending on the specific service environment. This program investigated the feasibility of measuring refractory wall thickness with an impact-echo method while at operating temperature (wall temperatures exceeding 500 C). The impact-echo method uses the impact of a small sphere with the surface of the test object to send a stress wave into the object. In a plate-like structure, the stress wave reflects back to the front surface, reverberating in the structure and causing a periodic surface displacement whose frequency is inversely proportional to the thickness of the test object. Impact-echo testing was chosen because it requires access to only one side of the test object and could be performed during the operation of a refractory structure. Commercially-available impact-echo instrumentation is available for room temperature use for a variety of tests on concrete. The enabling technology for this work was to use a high-temperature piezoelectric material, aluminum nitride, as the receiving sensor for the stress waves, allowing its use on refractories during furnace operation.

University of Dayton

2004-04-30T23:59:59.000Z

226

Observing Groups of Solitary Internal Waves and Turbulence with BATFISH and Echo-Sounder  

Science Conference Proceedings (OSTI)

Acoustic backscatter from a 200 kHz echo-sounder and temperature fine-structure from a towed CTD (BAT-FISH) am compared prior to and during the passage of a group of large-amplitude internal waves on the continental shelf off Nova Scotia. The ...

H. Sandstrom; J. A. Elliot; N. A. Cchrane

1989-07-01T23:59:59.000Z

227

Automatic Detection of Fixed Echoes in Sodar Facsimile Records Using the Wavelet Transform  

Science Conference Proceedings (OSTI)

A method to detect and remove fixed echoes in sodar facsimile records is described. This method is based on the capability of the wavelet transform to objectively detect singularities in signals, and it is adapted to two-tone facsimile records. ...

J. A. Kalogiros; C. G. Helmis

1999-06-01T23:59:59.000Z

228

A 4-Yr Climatology of Cold-Season Bow Echoes over the Continental United States  

Science Conference Proceedings (OSTI)

A search of radar mosaics and level-II Weather Surveillance Radar-1988 Doppler (WSR-88D) data revealed 51 cold-season (October–April) bow echoes that occurred in the contiguous United States from 1997–98 to 2000–01. Proximity soundings indicated ...

Patrick C. Burke; David M. Schultz

2004-12-01T23:59:59.000Z

229

Fuzzy Rule–Based Approach for Detection of Bounded Weak-Echo Regions in Radar Images  

Science Conference Proceedings (OSTI)

A method for the detection of a bounded weak-echo region (BWER) within a storm structure that can help in the prediction of severe weather phenomena is presented. A fuzzy rule–based approach that takes care of the various uncertainties associated ...

Nikhil R. Pal; Achintya K. Mandal; Srimanta Pal; Jyotirmay Das; V. Lakshmanan

2006-09-01T23:59:59.000Z

230

The Origin of Severe Winds in a Tornadic Bow-Echo Storm over Northern Switzerland  

Science Conference Proceedings (OSTI)

A severe bow-echo storm over northern Switzerland is investigated. Wind damage occurred along a track 15 km long and some 100 m wide. Damage data, meteorological data from a ground micronet, and Doppler radar data are analyzed. Volume-scan radar ...

Willi Schmid; Hans-Heinrich Schiesser; Markus Furger; Mario Jenni

2000-01-01T23:59:59.000Z

231

Phosphorus-31 MRI of hard and soft solids using quadratic echo line-narrowing  

E-Print Network (OSTI)

Phosphorus-31 MRI of hard and soft solids using quadratic echo line-narrowing Merideth A. Freya gradients in sync with this line-narrowing sequence offers a fresh approach to carry out MRI of hard). Extending the reach of MRI to the study of other elements, and to hard or soft solids, opens new frontiers

Haller, Gary L.

232

Using Echo State Networks for Anomaly Detection in Underground Coal Mines  

Science Conference Proceedings (OSTI)

We investigate the problem of identifying anomalies in monitoring critical gas concentrations using a sensor network in an underground coal mine. In this domain, one of the main problems is a provision of mine specific anomaly detection, with cyclical ... Keywords: sensor networks, anomaly detection, recurrent neural networks, echo state networks, bayesian networks, coal mines

Oliver Obst; X. Rosalind Wang; Mikhail Prokopenko

2008-04-01T23:59:59.000Z

233

Modified NLMF adaptation of Volterra filters used for nonlinear acoustic echo cancellation  

Science Conference Proceedings (OSTI)

When dealing with adaptive nonlinear filters used in acoustic echo cancellation, the tradeoff between convergence rate and steady-state error is an important issue. This tradeoff is favorably addressed here using a modified version of the normalized ... Keywords: Adaptive algorithms, Convergence rate, Error norm, Volterra filters

Cristian Contan; Botond Sandor Kirei; Marina Dana Topa

2013-05-01T23:59:59.000Z

234

Using the Inverted Echo Sounder to Measure Vertical Profiles of Gulf Stream Temperature and Geostrophic Velocity  

Science Conference Proceedings (OSTI)

The methodology for converting the travel time measurement of the inverted echo sounder (IES) into an amplitude of the first baroclinic dynamical mode, A1, is presented. For a Gulf Stream IES record the so-generated A1(t) time series is used to ...

Robert S. Pickart; D. Randolph Watts

1990-02-01T23:59:59.000Z

235

Observations of Inertia-Gravity Waves in the Atlantic from Inverted Echo Sounders during FGGE  

Science Conference Proceedings (OSTI)

The study is based on observations from inverted echo sounders anchored near the equator in the western Atlantic Ocean. It appears to be a good method of detecting inertia-gravity waves with large vertical scale. The spectral analysis of the ...

Silvia Garzoli; Eli Joel Katz

1981-11-01T23:59:59.000Z

236

Neutron Interferometry with Polarized Neutrons as an ...  

Science Conference Proceedings (OSTI)

... One approach to achieve this is to employ the Power of One Qubit ... Our experimental setup is outlined in Figure 1 A transmission supermirror spin ...

2013-07-23T23:59:59.000Z

237

NEUTRONIC REACTOR  

DOE Patents (OSTI)

This patent relates to neutronic reactors of the heterogeneous water cooled type, and in particular to a fuel element charging and discharging means therefor. In the embodiment illustrated the reactor contains horizontal, parallel coolant tubes in which the fuel elements are disposed. A loading cart containing a magnzine for holding a plurality of fuel elements operates along the face of the reactor at the inlet ends of the coolant tubes. The loading cart is equipped with a ram device for feeding fuel elements from the magazine through the inlot ends of the coolant tubes. Operating along the face adjacent the discharge ends of the tubes there is provided another cart means adapted to receive irradiated fuel elements as they are forced out of the discharge ends of the coolant tubes by the incoming new fuel elements. This cart is equipped with a tank coataining a coolant, such as water, into which the fuel elements fall, and a hydraulically operated plunger to hold the end of the fuel element being discharged. This inveation provides an apparatus whereby the fuel elements may be loaded into the reactor, irradiated therein, and unloaded from the reactor without stopping the fiow of the coolant and without danger to the operating personnel.

Ohlinger, L.A.; Wigner, E.P.; Weinberg, A.M.; Young, G.J.

1958-09-01T23:59:59.000Z

238

Using {sup 171,173}Yb(d,p{gamma}) to Benchmark a Surrogate Reaction for Neutron Capture  

SciTech Connect

The {sup 171,173}Yb(d,p{gamma}) reactions have been measured to determine the efficacy of this reaction as a surrogate for neutron capture on radioactive nuclei. Preliminary results for the surrogate cross section ratios, with gating conditions that best mimic the spin distribution of neutron capture, reproduce the Wisshak et al., (n,{gamma}) cross section ratios within 15%.

Hatarik, R.; Cizewski, J. A.; Hatarik, A. M.; O'Malley, P. D. [Rutgers University, New Brunswick NJ 08903 (United States); Bernstein, L. A.; Bleuel, D. L.; Burke, J. T.; Lesher, S. R. [Lawrence Livermore National Laboratory, Livermore CA 94550 (United States); Gibelin, J.; Phair, L. [Lawrence Berkeley National Laboratory, Berkeley CA 94720 (United States); Swan, T. [Rutgers University, New Brunswick NJ 08903 (United States); University of Surrey, Guildford GU2 7XH, Surrey (United Kingdom)

2009-03-10T23:59:59.000Z

239

Neutron streak camera  

DOE Patents (OSTI)

Apparatus for improved sensitivity and time resolution of a neutron measurement. The detector is provided with an electrode assembly having a neutron sensitive cathode which emits relatively low energy secondary electrons. The neutron sensitive cathode has a large surface area which provides increased sensitivity by intercepting a greater number of neutrons. The cathode is also curved to compensate for differences in transit time of the neutrons emanating from the point source. The slower speeds of the secondary electrons emitted from a certain portion of the cathode are matched to the transit times of the neutrons impinging thereupon.

Wang, C.L.

1981-05-14T23:59:59.000Z

240

Organic metal neutron detector  

DOE Patents (OSTI)

A device for detection of neutrons comprises: as an active neutron sensing element, a conductive organic polymer having an electrical conductivity and a cross-section for said neutrons whereby a detectable change in said conductivity is caused by impingement of said neutrons on the conductive organic polymer which is responsive to a property of said polymer which is altered by impingement of said neutrons on the polymer; and means for associating a change in said alterable property with the presence of neutrons at the location of said device.

Butler, M.A.; Ginley, D.S.

1984-11-21T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Layered semiconductor neutron detectors  

SciTech Connect

Room temperature operating solid state hand held neutron detectors integrate one or more relatively thin layers of a high neutron interaction cross-section element or materials with semiconductor detectors. The high neutron interaction cross-section element (e.g., Gd, B or Li) or materials comprising at least one high neutron interaction cross-section element can be in the form of unstructured layers or micro- or nano-structured arrays. Such architecture provides high efficiency neutron detector devices by capturing substantially more carriers produced from high energy .alpha.-particles or .gamma.-photons generated by neutron interaction.

Mao, Samuel S; Perry, Dale L

2013-12-10T23:59:59.000Z

242

Spinning fluids reactor  

SciTech Connect

A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.

Miller, Jan D; Hupka, Jan; Aranowski, Robert

2012-11-20T23:59:59.000Z

243

MATERIALS FOR SPALLATION NEUTRON SOURCES: IV: Neutronics  

Science Conference Proceedings (OSTI)

The Department of Energy has initiated a pre-conceptual design study for the National Spallation Neutron Source (NSNS) and given preliminary approval for the ...

244

GSE statistics without spin  

E-Print Network (OSTI)

Energy levels statistics following the Gaussian Symplectic Ensemble (GSE) of Random Matrix Theory have been predicted theoretically and observed numerically in numerous quantum chaotic systems. However in all these systems there has been one unifying feature: the combination of half-integer spin and time-reversal invariance. Here we provide an alternative mechanism for obtaining GSE statistics that is based on geometric symmetries of a quantum system which alleviates the need for spin. As an example, we construct a quantum graph with a particular discrete symmetry given by the quaternion group Q8. GSE statistics is then observed within one of its subspectra.

Christopher H. Joyner; Sebastian Müller; Martin Sieber

2013-02-11T23:59:59.000Z

245

Measurement of the Parity Non-Conserving Neutron Spin ...  

Science Conference Proceedings (OSTI)

... is dominated by counting statistics, and hence, an ... processes dominate at low energy so investigations ... At low energies these processes are best ...

2013-07-23T23:59:59.000Z

246

Quantum Teleportation from a Propagating Photon to a Solid-State Spin Qubit  

E-Print Network (OSTI)

The realization of a quantum interface between a propagating photon used for transmission of quantum information, and a stationary qubit used for storage and manipulation, has long been an outstanding goal in quantum information science. A method for implementing such an interface between dissimilar qubits is quantum teleportation, which has attracted considerable interest not only as a versatile quantum-state-transfer method but also as a quantum computational primitive. Here, we experimentally demonstrate transfer of quantum information carried by a photonic qubit to a quantum dot spin qubit using quantum teleportation. In our experiment, a single photon in a superposition state of two colors -- a photonic qubit is generated using selective resonant excitation of a neutral quantum dot. We achieve an unprecedented degree of indistinguishability of single photons from different quantum dots by using local electric and magnetic field control. To teleport a photonic qubit, we generate an entangled spin-photon state in a second quantum dot located 5 meters away from the first and interfere the photons from the two dots in a Hong-Ou-Mandel set-up. A coincidence detection at the output of the interferometer heralds successful teleportation, which we verify by measuring the resulting spin state after its coherence time is prolonged by an optical spin-echo pulse sequence. The demonstration of successful inter-conversion of photonic and semiconductor spin qubits constitute a major step towards the realization of on-chip quantum networks based on semiconductor nano-structures.

Wei-bo Gao; P. Fallahi; E. Togan; A. Delteil; Y. S. Chin; J. Miguel-Sanchez; A. Imamoglu

2013-07-03T23:59:59.000Z

247

Instruments | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

NScD Careers NScD Careers Supporting Organizations Neutron Science Home | Science & Discovery | Neutron Science | Instruments SHARE Instruments at SNS and HFIR SNS Instrument Name HFIR Instrument Name 1B NOMAD - Nanoscale-Ordered Materials Diffractometer CG-1 Development Beam Line 2 BASIS - Backscattering Spectrometer CG-1D IMAGING - Neutron Imaging Prototype Facility 3 SNAP - Spallation Neutrons and Pressure Diffractometer CG-2 GP-SANS - General-Purpose Small-Angle Neutron Scattering Diffractometer 4A MR - Magnetism Reflectometer CG-3 Bio-SANS - Biological Small-Angle Neutron Scattering Instrument 4B LR - Liquids Reflectometer CG-4C CTAX - Cold Neutron Triple-Axis Spectrometer 5 CNCS - Cold Neutron Chopper Spectrometer HB-1 PTAX - Polarized Triple-Axis Spectrometer

248

Ultrafast neutron detector  

DOE Patents (OSTI)

A neutron detector of very high temporal resolution is described. It may be used to measure distributions of neutrons produced by fusion reactions that persist for times as short as about 50 picoseconds.

Wang, C.L.

1985-06-19T23:59:59.000Z

249

Pulsed-neutron monochromator  

DOE Patents (OSTI)

In one aspect, the invention is an improved pulsed-neutron monochromator of the vibrated-crystal type. The monochromator is designed to provide neutron pulses which are characterized both by short duration and high density. A row of neutron-reflecting crystals is disposed in a neutron beam to reflect neutrons onto a common target. The crystals in the row define progressively larger neutron-scattering angles and are vibrated sequentially in descending order with respect to the size of their scattering angles, thus generating neutron pulses which arrive simultaneously at the target. Transducers are coupled to one end of the crystals to vibrate them in an essentially non-resonant mode. The transducers propagate transverse waves in the crystal which progress longitudinally therein. The waves are absorbed at the undriven ends of the crystals by damping material mounted thereon. In another aspect, the invention is a method for generating neutron pulses characterized by high intensity and short duration.

Mook, H.A. Jr.

1984-01-01T23:59:59.000Z

250

Procurement - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

for the acquisition of goods and services for neutron scattering operations at SNS and HFIR. If you're interested in conducting business with the Neutron Sciences Directorate or...

251

Facilities | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Isotope Reactor. The pulsed neutron source at SNS and the continuous neutron source at HFIR complement each other well and, along with their state-of-the-art instruments, provide...

252

Spin-Polarized Hydrogen publications  

Science Conference Proceedings (OSTI)

For more information about my work on spin-polarized atomic hydrogen, consult the following papers: Godfried, HP, Eliel ...

253

NIST: Methane Symmetry Operations - Nuclear spin stats  

Science Conference Proceedings (OSTI)

... 9.2 Nuclear spin statistics and overall parities. ... Molecule, Rovibrational species, Nuclear spin functions, Overall species, Statistical weight. ...

254

NIST: Methane Symmetry Operations - Nuclear spin functions  

Science Conference Proceedings (OSTI)

Methane Symmetry Operations. 9. Symmetry Properties of Laboratory-Fixed Nuclear Spin Functions, Nuclear Spin Statistics, and Parities. ...

255

Spin Transport in Semiconductor heterostructures  

SciTech Connect

The focus of the research performed under this grant has been the investigation of spin transport in magnetic semiconductor heterostructures. The interest in these systems is motivated both by their intriguing physical properties, as the physical embodiment of a spin-polarized Fermi liquid, as well as by their potential applications as spintronics devices. In our work we have analyzed several different problems that affect the spin dynamics in single and bi-layer spin-polarized two-dimensional (2D) systems. The topics of interests ranged from the fundamental aspects of the electron-electron interactions, to collective spin and charge density excitations and spin transport in the presence of the spin-orbit coupling. The common denominator of these subjects is the impact at the macroscopic scale of the spin-dependent electron-electron interaction, which plays a much more subtle role than in unpolarized electron systems. Our calculations of several measurable parameters, such as the excitation frequencies of magneto-plasma modes, the spin mass, and the spin transresistivity, propose realistic theoretical estimates of the opposite-spin many-body effects, in particular opposite-spin correlations, that can be directly connected with experimental measurements.

Domnita Catalina Marinescu

2011-02-22T23:59:59.000Z

256

Advanced neutron absorber materials  

DOE Patents (OSTI)

A neutron absorbing material and method utilizing rare earth elements such as gadolinium, europium and samarium to form metallic glasses and/or noble base nano/microcrystalline materials, the neutron absorbing material having a combination of superior neutron capture cross sections coupled with enhanced resistance to corrosion, oxidation and leaching.

Branagan, Daniel J. (Idaho Falls, ID); Smolik, Galen R. (Idaho Falls, ID)

2000-01-01T23:59:59.000Z

257

Arsenic activation neutron detector  

DOE Patents (OSTI)

A detector of bursts of neutrons from a deuterium-deuteron reaction includes a quantity of arsenic adjacent a gamma detector such as a scintillator and photomultiplier tube. The arsenic is activated by the 2.5-MeV neutrons to release gamma radiation which is detected to give a quantitative representation of detected neutrons.

Jacobs, E.L.

1980-01-28T23:59:59.000Z

258

Physics @ Oxford SCATTERING NEUTRONS  

E-Print Network (OSTI)

1 Neutron Scattering Society of America (NSSA) Purpose and New Initiatives www.neutronscattering.org SNS/ANL School on Neutron and X-Ray Scattering June 2011 Visit us now on Facebook #12;2 What is the NSSA? NSSA is an organization of scientists and engineers with a common interest in using neutron

Herz, Laura M.

259

RHIC spin flipper commissioning results  

Science Conference Proceedings (OSTI)

The five AC dipole RHIC spin flipper design in the RHIC Blue ring was first tested during the RHIC 2012 polarized proton operation. The advantage of this design is to eliminate the vertical coherent betatron oscillations outside the spin flipper. The closure of each ac dipole vertical bump was measured with orbital response as well as spin. The effect of the rotating field on the spin motion by the spin flipper was also confirmed by measuring the suppressed resonance at Q{sub s} = 1 - Q{sub osc}.

Bai M.; Roser, T.; Dawson, C.; Kewisch, J.; Makdisi, Y.; Oddo, P.; Pai, C.; Pile, P.

2012-05-20T23:59:59.000Z

260

Decay of the Loschmidt echo in a time-dependent environment  

E-Print Network (OSTI)

We study the decay rate of the Loschmidt echo or fidelity in a chaotic system under a time-dependent perturbation $V(q,t)$ with typical strength $\\hbar/\\tau_{V}$. The perturbation represents the action of an uncontrolled environment interacting with the system, and is characterized by a correlation length $\\xi_0$ and a correlation time $\\tau_0$. For small perturbation strengths or rapid fluctuating perturbations, the Loschmidt echo decays exponentially with a rate predicted by the Fermi Golden Rule, $1/\\tilde{\\tau}= \\tau_{c}/\\tau_{V}^2$, where typically $\\tau_{c} \\sim \\min[\\tau_{0},\\xi_0/v]$ with $v$ the particle velocity. Whenever the rate $1/\\tilde{\\tau}$ is larger than the Lyapunov exponent of the system, a perturbation independent Lyapunov decay regime arises. We also find that by speeding up the fluctuations (while keeping the perturbation strength fixed) the fidelity decay becomes slower, and hence, one can protect the system against decoherence.

Fernando M. Cucchietti; Caio H. Lewenkopf; Horacio M. Pastawski

2006-01-11T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Microsoft Word - TR_SiteEcho_Final_R1-V2.doc  

NLE Websites -- All DOE Office Websites (Extended Search)

TOPICAL REPORT: TEST RESULTS FOR A COMBINED CYCLE POWER PLANT WITH OXIDATION CATALYST AND SCR AT SITE ECHO February 2005 CEC-500-2005-042 Revision 1.2 October 26, 2004 ii When citing this document, please use the following citation: England, G.C., Wien, S., McGrath, T.P., and Hernandez, D., "Development of Fine Particulate Emission Factors and Speciation Profiles for Oil and Gas-fired Combustion Systems, Topical Report: Test Results for a Combined Cycle Power Plant with Oxidation Catalyst and SCR at Site Echo," 2004. Revision 1.2 October 26, 2004 iii DEVELOPMENT OF FINE PARTICULATE EMISSION FACTORS AND SPECIATION PROFILES FOR OIL- AND GAS-FIRED COMBUSTION

262

Kangley - Echo Lake Transmission Line Project, Supplemental Draft Environmental Impact Statement  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Bonneville Power Administration Bonneville Power Administration P.O. Box 491 Vancouver, Washington 98666-0491 TRANSMISSION BUSINESS LINE January 14, 2003 In reply refer to: T-DITT-2 To: People Interested in the Kangley-Echo Lake Transmission Line Project Bonneville Power Administration (BPA) has completed a supplemental draft Environmental Impact Statement (SDEIS) for the proposed Kangley-Echo Lake Transmission Line Project. The proposed line in central King County, Washington is needed to accommodate electrical growth and reliability concerns in the Puget Sound area. The SDEIS analyzes four additional transmission alternatives not analyzed in detail in the draft Environmental Impact Statement (DEIS) issued in June 2001, and a number of non-transmission alternatives. This letter provides

263

High energy neutron dosimeter  

DOE Patents (OSTI)

A device for measuring dose equivalents in neutron radiation fields is described. The device includes nested symmetrical hemispheres (forming spheres) of different neutron moderating materials that allow the measurement of dose equivalents from 0.025 eV to past 1 GeV. The layers of moderating material surround a spherical neutron counter. The neutron counter is connected by an electrical cable to an electrical sensing means which interprets the signal from the neutron counter in the center of the moderating spheres. The spherical shape of the device allows for accurate measurement of dose equivalents regardless of its positioning. 2 figures.

Rai, K.S.F.

1994-01-11T23:59:59.000Z

264

High energy neutron dosimeter  

DOE Patents (OSTI)

A device for measuring dose equivalents in neutron radiation fields. The device includes nested symmetrical hemispheres (forming spheres) of different neutron moderating materials that allow the measurement of dose equivalents from 0.025 eV to past 1 GeV. The layers of moderating material surround a spherical neutron counter. The neutron counter is connected by an electrical cable to an electrical sensing means which interprets the signal from the neutron counter in the center of the moderating spheres. The spherical shape of the device allows for accurate measurement of dose equivalents regardless of its positioning.

Sun, Rai Ko S.F. (Albany, CA)

1994-01-01T23:59:59.000Z

265

VibroTactor: low-cost placement-aware technique using vibration echoes on mobile devices  

Science Conference Proceedings (OSTI)

In this paper, we present a low-cost placement-aware technique, called VibroTactor, which allows mobile devices to determine where they are placed (e.g., in a pocket, on a phone holder, on the bed, or on the desk). This is achieved by filtering and analyzing ... Keywords: context-aware, pattern recognition, placement detection, pseudo sensor, sensor repurposing, vibration echoes

Sungjae Hwang; Kwangyun Wohn

2013-03-01T23:59:59.000Z

266

Moving Cellular Structure of Fog Echoes Obtained with a Millimeter-Wave Scanning Doppler Radar at Kushiro, Japan  

Science Conference Proceedings (OSTI)

Observations of fogs with a millimeter-wave scanning Doppler radar were conducted at Kushiro in Hokkaido, Japan, in the summer seasons of 1999 and 2000. Three typical types of plan position indicator (PPI) displays were observed: cellular echoes ...

Akihisa Uematsu; Hiroyuki Hashiguchi; Michihiro Teshiba; Hisamichi Tanaka; Koichi Hirashima; Shoichiro Fukao

2005-08-01T23:59:59.000Z

267

Vertical Velocity and Buoyancy Characteristics of Coherent Echo Plumes in the Convective Boundary Layer, Detected by a Profiling Airborne Radar  

Science Conference Proceedings (OSTI)

Aircraft and airborne millimeter-wave radar observations are used to interpret the dynamics of radar echoes and radar-inferred updrafts within the well-developed, weakly sheared continental convective boundary layer. Vertically pointing radar ...

Qun Miao; Bart Geerts; Margaret LeMone

2006-06-01T23:59:59.000Z

268

Megadroughts in Southwestern North America in Millennium-Length ECHO-G Simulations and their Comparison to Proxy Drought Reconstructions  

Science Conference Proceedings (OSTI)

Simulated hydroclimate variability in millennium-length forced transient and control simulations from the ECHO-G coupled Atmosphere Ocean General Circulation Model (AOGCM) is analyzed and compared to a thousand years of reconstructed Palmer ...

Sloan Coats; Jason E. Smerdon; Richard Seager; Benjamin I. Cook; J. F. González-Rouco

269

Low-Level Mesovortices within Squall Lines and Bow Echoes. Part I: Overview and Dependence on Environmental Shear  

Science Conference Proceedings (OSTI)

This two-part study proposes fundamental explanations of the genesis, structure, and implications of low-level meso-?-scale vortices within quasi-linear convective systems (QLCSs) such as squall lines and bow echoes. Such “mesovortices” are ...

Morris L. Weisman; Robert J. Trapp

2003-11-01T23:59:59.000Z

270

An Acoustic Telemetry System Implemented for Real-Time Monitoring of the Gulf Stream with Inverted Echo Sounders  

Science Conference Proceedings (OSTI)

From August 1989 until August 1990, a simple acoustic telemetry system was used for obtaining real-time data from four inverted echo sounders (IESs) deployed in the Synoptic Ocean Prediction Experiment (SYNOP) inlet array in the Gulf Stream east ...

Stephan D. Howden; D. Randolph Watts; Karen L. Tracey; H. Thomas Rossby

1994-04-01T23:59:59.000Z

271

Torsion-induced spin precession  

E-Print Network (OSTI)

We investigate the motion of a spinning test particle in a spatially-flat FRW-type space-time in the framework of the Einstein-Cartan theory. The space-time has a torsion arising from a spinning fluid filling the space-time. We show that for spinning particles with nonzero transverse spin components, the torsion induces a precession of particle spin around the direction of the fluid spin. We also show that a charged spinning particle moving in a torsion-less spatially-flat FRW space-time in the presence of a uniform magnetic field undergoes a precession of a different character. PACS: 04.40.Nr, 04.90.+e 1

Morteza Mohseni

2008-01-01T23:59:59.000Z

272

Spallation Neutron Source, SNS  

NLE Websites -- All DOE Office Websites (Extended Search)

Spallation Neutron Source Spallation Neutron Source Providing the most intense pulsed neutron beams in the world... Accumulator Ring Commissioning Latest Step for Spallation Neutron Source The Spallation Neutron Source, located at Oak Ridge National Laboratory, has passed another milestone on the way to completion this year--the commissioning of the proton accumulator ring. Brookhaven led the design and construction of the accumulator ring, which will allow an order of magnitude more beam power than any other facility in the world. The Spallation Neutron Source (SNS) is an accelerator-based neutron source being built in Oak Ridge, Tennessee, by the U.S. Department of Energy. The figure on the right shows a schematic of the accumulator ring and transport beam lines that are being designed and built by Brookhaven

273

Kangley-Echo Lake Transmission Line Project Final Environmental Impact Statement  

Science Conference Proceedings (OSTI)

BPA proposes to build a single-circuit 500-kV transmission line from a tap point on an existing 500-kV line near Kangley, Washington, to its Echo Lake Substation near North Bend, Washington. The proposed route for this line, also called Alternative 1, is about nine miles long. About five miles of the proposed route would go through the Cedar River Municipal Watershed. In addition, Echo Lake Substation would be expanded about three acres to the east and new equipment would be installed there to accommodate the new line (common to all transmission alternatives). This alternative was proposed because it would be located immediately parallel to an existing BPA existing 500-kV transmission line, the Raver-Echo Lake Transmission Line. Locating a new line next to an existing one reduces right-of-way (ROW) clearing needed for the new line and reduces the need for additional access roads. Lattice steel transmission towers would support the 500-kV transmission line. These structures average 135 feet high, with the average span between towers of about 1,150 feet.

N /A

2003-06-20T23:59:59.000Z

274

Large Searching for Higher Dimensional Gravity with Neutron Experiments  

SciTech Connect

N-dimensional gravity is analized in the context of recent work on 'large' supplementary dimensions. A simple derivation of the compactification radii for additional dimensions in the universe is made, as a function of the Planck and the electro-weak scales. It is argued that the modified gravitational force would give rise to effects that might be within the detection range of dedicated neutron experiments. An analysis suggests that neutron scattering off atomic nuclei with null spin may provide an experimental test for these ideas.

Frank, Alejandro [Instituto de Ciencias Nucleares, UNAM, Apdo. Postal 70-543, 04510 Mexico, D.F. (Mexico)

2007-10-26T23:59:59.000Z

275

Imaging and Neutrons - IAN 2006 - Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

SNS Home Saturday, January 11, 2014 SNS Home Saturday, January 11, 2014 Go IAN 2006 Imaging and Neutrons 2006 October 23-25, 2006 Iran Thomas Auditorium Central Laboratory and Office Building Spallation Neutron Source Oak Ridge National Laboratory, Oak Ridge, TN Who Should Attend Synopsis Goals and Expected Outcomes Application Areas Techniques International Advisory Committee Local Organizing Committee Agenda with Presentations NEW Confirmed Speakers Frequently Asked Questions - FAQ Satellite Workshop - Progress in Electron Volt Neutron Spectroscopy eV Worshop Agenda presentations NEW Lodging, Transportation, Bus Schedule Location Directions and Map Registration CLOSED Abstracts, Posters, Contributed Talks Scholarships Sponsors Vendors May Attend Relevant Reports Important Dates Weather Attractions

276

NEUTRON DENSITY CONTROL IN A NEUTRONIC REACTOR  

DOE Patents (OSTI)

The method and means for controlling the neutron density in a nuclear reactor is described. It describes the method and means for flattening the neutron density distribution curve across the reactor by spacing the absorbing control members to varying depths in the central region closer to the center than to the periphery of the active portion of the reactor to provide a smaller neutron reproduction ratio in the region wherein the members are inserted, than in the remainder of the reactor thereby increasing the over-all potential power output.

Young, G.J.

1959-06-30T23:59:59.000Z

277

Teleparallel Spin Connection  

E-Print Network (OSTI)

A new expression for the spin connection of teleparallel gravity is proposed, given by minus the contorsion tensor plus a zero connection. The corresponding minimal coupling is covariant under local Lorentz transformation, and equivalent to the minimal coupling prescription of general relativity. With this coupling prescription, therefore, teleparallel gravity turns out to be fully equivalent to general relativity, even in the presence of spinor fields.

V. C. de Andrade; L. C. T. Guillen; J. G. Pereira

2001-04-30T23:59:59.000Z

278

Measurement of the neutron $?$-asymmetry parameter $A_0$ with ultracold neutrons  

E-Print Network (OSTI)

We present a detailed report of a measurement of the neutron $\\beta$-asymmetry parameter $A_0$, the parity-violating angular correlation between the neutron spin and the decay electron momentum, performed with polarized ultracold neutrons (UCN). UCN were extracted from a pulsed spallation solid deuterium source and polarized via transport through a 7-T magnetic field. The polarized UCN were then transported through an adiabatic-fast-passage spin-flipper field region, prior to storage in a cylindrical decay volume situated within a 1-T $2 \\times 2\\pi$ solenoidal spectrometer. The asymmetry was extracted from measurements of the decay electrons in multiwire proportional chamber and plastic scintillator detector packages located on both ends of the spectrometer. From an analysis of data acquired during runs in 2008 and 2009, we report $A_0 = -0.11966 \\pm 0.00089_{-0.00140} ^{+0.00123}$, from which we extract a value for the ratio of the weak axial-vector and vector coupling constants of the nucleon, $\\lambda = g_A/g_V = -1.27590 \\pm 0.00239_{-0.00377}^{+0.00331}$. Complete details of the analysis are presented.

UCNA Collaboration; B. Plaster; R. Rios; H. O. Back; T. J. Bowles; L. J. Broussard; R. Carr; S. Clayton; S. Currie; B. W. Filippone; A. Garcia; P. Geltenbort; K. P. Hickerson; J. Hoagland; G. E. Hogan; B. Hona; A. T. Holley; T. M. Ito; C. -Y. Liu; J. Liu; M. Makela; R. R. Mammei; J. W. Martin; D. Melconian; M. P. Mendenhall; C. L. Morris; R. Mortensen; R. W. Pattie, Jr.; A. Perez Galvan; M. L. Pitt; J. C. Ramsey; R. Russell; A. Saunders; R. Schmid; S. J. Seestrom; S. Sjue; W. E. Sondheim; E. Tatar; B. Tipton; R. B. Vogelaar; B. VornDick; C. Wrede; Y. P. Xu; H. Yan; A. R. Young; J. Yuan

2012-07-25T23:59:59.000Z

279

Measurement of the neutron $\\beta$-asymmetry parameter $A_0$ with ultracold neutrons  

E-Print Network (OSTI)

We present a detailed report of a measurement of the neutron $\\beta$-asymmetry parameter $A_0$, the parity-violating angular correlation between the neutron spin and the decay electron momentum, performed with polarized ultracold neutrons (UCN). UCN were extracted from a pulsed spallation solid deuterium source and polarized via transport through a 7-T magnetic field. The polarized UCN were then transported through an adiabatic-fast-passage spin-flipper field region, prior to storage in a cylindrical decay volume situated within a 1-T $2 \\times 2\\pi$ solenoidal spectrometer. The asymmetry was extracted from measurements of the decay electrons in multiwire proportional chamber and plastic scintillator detector packages located on both ends of the spectrometer. From an analysis of data acquired during runs in 2008 and 2009, we report $A_0 = -0.11966 \\pm 0.00089_{-0.00140} ^{+0.00123}$, from which we extract a value for the ratio of the weak axial-vector and vector coupling constants of the nucleon, $\\lambda = g...

Plaster, B; Back, H O; Bowles, T J; Broussard, L J; Carr, R; Clayton, S; Currie, S; Filippone, B W; Garcia, A; Geltenbort, P; Hickerson, K P; Hoagland, J; Hogan, G E; Hona, B; Holley, A T; Ito, T M; Liu, C -Y; Liu, J; Makela, M; Mammei, R R; Martin, J W; Melconian, D; Mendenhall, M P; Morris, C L; Mortensen, R; Pattie, R W; Jr.,; Galvan, A Perez; Pitt, M L; Ramsey, J C; Russell, R; Saunders, A; Schmid, R; Seestrom, S J; Sjue, S; Sondheim, W E; Tatar, E; Tipton, B; Vogelaar, R B; VornDick, B; Wrede, C; Xu, Y P; Yan, H; Young, A R; Yuan, J

2012-01-01T23:59:59.000Z

280

AN ALGORITHM FOR THE GENERATION OF NUCLEAR SPIN SPECIES AND NUCLEAR SPIN STATISTICAL WEIGHTS  

E-Print Network (OSTI)

Chemistry AN ALGORITHM FOR THE GENERATION OF NUCLEAR SPINSPECIES AND NUCLEAR SPIN STATISTICAL WEIGHTS K.for the Generation of Nuclear Spin and Nuclear Spin

Balasubramanian, K.

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Neutron Reflectivity and Magnetization Reversal in Heusler ...  

Science Conference Proceedings (OSTI)

... Giant Magnetoresistance Spintronics and Spin Valves Heusler Alloys ? Introduce Samples ... Direction SPINTRONICS AND SPIN VALVES ...

2010-09-03T23:59:59.000Z

282

The Neutron Residual Stress Mapping Facility at HFIR | ORNL Neutron...  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Residual Stress Mapping Facility at HFIR Neutron Residual Stress Mapping Facility (HB-2B) Neutron Residual Stress Mapping Facility (HB-2B). The HB-2B beam port is optimized...

283

Neutron sources and applications  

Science Conference Proceedings (OSTI)

Review of Neutron Sources and Applications was held at Oak Brook, Illinois, during September 8--10, 1992. This review involved some 70 national and international experts in different areas of neutron research, sources, and applications. Separate working groups were asked to (1) review the current status of advanced research reactors and spallation sources; and (2) provide an update on scientific, technological, and medical applications, including neutron scattering research in a number of disciplines, isotope production, materials irradiation, and other important uses of neutron sources such as materials analysis and fundamental neutron physics. This report summarizes the findings and conclusions of the different working groups involved in the review, and contains some of the best current expertise on neutron sources and applications.

Price, D.L. [ed.] [Argonne National Lab., IL (United States); Rush, J.J. [ed.] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1994-01-01T23:59:59.000Z

284

Spallation Neutron Source  

NLE Websites -- All DOE Office Websites (Extended Search)

D/gim D/gim Spallation Neutron Source SNS is an accelerator-based neutron source. This one-of-a-kind facility pro- vides the most intense pulsed neutron beams in the world. When ramped up to its full beam power of 1.4 MW, SNS will be eight times more powerful than today's best facility. It will give researchers more detailed snapshots of the smallest samples of physical and biological materials than ever before

285

Feedback control of spin systems  

E-Print Network (OSTI)

The feedback stabilization problem for ensembles of coupled spin 1/2 systems is discussed from a control theoretic perspective. The noninvasive nature of the bulk measurement allows for a fully unitary and deterministic closed loop. The Lyapunov-based feedback design presented does not require spins that are selectively addressable. With this method, it is possible to obtain control inputs also for difficult tasks, like suppressing undesired couplings in identical spin systems.

Claudio Altafini

2006-01-03T23:59:59.000Z

286

Neutron-detection apparatus  

DOE Patents (OSTI)

An atomic fission counting apparatus used for neutron detection is provided with spirally curved electrode plates uniformly spaced apart in a circular array and coated with fissile material.

Kopp, M.K.; Valentine, K.H.

1981-04-24T23:59:59.000Z

287

Education | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Matter Physics Neutron Scattering in Quantum Condensed Matter Physics flyer The first cyber enabled collaborative graduate course was launched in Fall semester 2012. It addresses...

288

Industry - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Industry banner Industry banner Neutron scattering research has applications in practically every field, and neutron research at ORNL is leading to productive partnerships with the industrial and business communities. We welcome proposals for all types of research, including those involving proprietary work. Recent studies have led to discoveries with potential applications in fields such as medicine, energy, and various metals technologies. For more information, please see our recent research highlights. Research Collaborations Industry-Driven Research Benefits Plastics Manufacturing Corning uses VULCAN to test limits of ceramic material for car emission controls, filtration devices Neutrons Probe Inner Workings of Batteries Industry and Neutron Science: Working To Make a Match

289

Physics Out Loud - Neutron  

NLE Websites -- All DOE Office Websites (Extended Search)

Matter Previous Video (Matter) Physics Out Loud Main Index Next Video (Niobium) Niobium Neutron Karl Slifer, a physicist based at the University of New Hampshire and who conducts...

290

Neutron Scattering Facilities  

NLE Websites -- All DOE Office Websites (Extended Search)

Gaithersburg, Maryland, USA Peruvian Institute of Nuclear Energy (IPEN), Lima, Peru Spallation Neutron Source, Oak Ridge National Laboratory, Tennessee, USA University of...

291

Neutron Scattering Web  

NLE Websites -- All DOE Office Websites (Extended Search)

at neutronsources.org. The information contained here in the Neutron Scattering Web has been transferred to the new site. We will leave the current content here for...

292

Magnetization of neutron matter  

SciTech Connect

In this paper, we compute magnetization of neutron matter at strong magnetic field using the lowest order constrained variational (LOCV) technique.

Bigdeli, M. [Department of Physics, Zanjan University, P.O. Box 45195-313, Zanjan (Iran, Islamic Republic of)

2011-09-21T23:59:59.000Z

293

Neutron detection apparatus  

DOE Patents (OSTI)

An atomic fission counting apparatus used for neutron detection is provided with spirally curved electrode plates uniformly spaced apart in a circular array and coated with fissile material.

Kopp, Manfred K. (Oak Ridge, TN); Valentine, Kenneth H. (Lenoir City, TN)

1983-01-01T23:59:59.000Z

294

Neutron Activation Calculator  

Science Conference Proceedings (OSTI)

... and incoherent scattering cross sections). Source neutrons (Ang, meV or m/s), Density (g/cm 3 or lattice), Thickness (cm). ...

295

Neutron Scattering Template  

NLE Websites -- All DOE Office Websites (Extended Search)

Acknowledgements The graphics used on the Neutron Scattering Web Pages were designed by Tami Sharley (Information and Publishing Services Division) and Jack Carpenter (Intense...

296

Neutrons in Biology, ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Scattering Sciences Division Oak Ridge National Laboratory Phone: 865.241.2897 SNS Logo HFIR Logo General Information The unique potential of neutron scattering in structural...

297

Neutrons in Biology, ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Scattering Sciences Division Oak Ridge National Laboratory Phone: 865.576.2779 SNS Logo HFIR Logo General Information The unique potential of neutron scattering in structural...

298

Neutrons in Biology, ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Materials Division Oak Ridge National Laboratory Phone: 865.241.5176 SNS Logo HFIR Logo General Information The unique potential of neutron scattering in structural...

299

ORNL Neutron Sciences Publications  

NLE Websites -- All DOE Office Websites (Extended Search)

at other facilties by Neutron Sciences Directorate staff. We strongly encourage SNS and HFIR users to submit citation information, including URLs, for all publications regarding...

300

Towards a Neutron Microscope  

Science Conference Proceedings (OSTI)

Towards a Neutron Microscope. Summary: ... The novel lens is a Wolter Optic similar in design to the telescope of the CHANDRA x-ray observatory. ...

2013-07-23T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Theory of Spin Transfer Torque  

Science Conference Proceedings (OSTI)

... In the phenomenon known as spin transfer torque, a current can give a jolt to thin magnetic layers sandwiched between nonmagnetic materials. ...

2013-06-28T23:59:59.000Z

302

Spin MOSFETs as a basis for spintronics  

Science Conference Proceedings (OSTI)

This article reviews a recently proposed new class of spin transistors referred to as spin metal-oxide-semiconductor field-effect transistors (spin MOSFETs), and their integrated circuit applications. The fundamental device structures, operating principle, ... Keywords: MOSFETs, Spintronics, spin MOSFETs, spin transistors

Satoshi Sugahara; Masaaki Tanaka

2006-05-01T23:59:59.000Z

303

Neutrons in Soft Matter Science | Education | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Complex Materials on Mesoscopic Scales Neutron in Soft Matter Science flyer The new cyber-enabled collaborative graduate course "Neutrons in Soft Matter Science: Complex...

304

Neutron Science Facilities Operating Status | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Science Facilities Operating Status High Flux Isotope Reactor The reactor is currently operating at 100% power for fuel cycle 449. Spallation Neutron Source SNS is shutdown...

305

Spin resonance strength calculations  

SciTech Connect

In calculating the strengths of depolarizing resonances it may be convenient to reformulate the equations of spin motion in a coordinate system based on the actual trajectory of the particle, as introduced by Kondratenko, rather than the conventional one based on a reference orbit. It is shown that resonance strengths calculated by the conventional and the revised formalisms are identical. Resonances induced by radiofrequency dipoles or solenoids are also treated; with rf dipoles it is essential to consider not only the direct effect of the dipole but also the contribution from oscillations induced by it.

Courant,E.D.

2008-10-06T23:59:59.000Z

306

Depth Profile of Uncompensated Spins in an Exchange-Bias System  

NLE Websites -- All DOE Office Websites (Extended Search)

Depth Profile of Uncompensated Depth Profile of Uncompensated Spins in an Exchange-Bias System Depth Profile of Uncompensated Spins in an Exchange-Bias System Print Wednesday, 25 January 2006 00:00 The phenomenon known as exchange bias at the interface between a ferromagnet and an antiferromagnet is currently a subject of intense research because of its applications in the magnetic recording and read-head industries. An international collaboration headed by researchers from the University of California, San Diego, has used resonant x-ray scattering and polarized-neutron reflectometry to determine the depth-dependent magnetization in an exchange-biased sample. These results provide atomic-level insights into the mechanism of exchange bias, specifically the involvement of mutual interactions between two kinds of uncompensated spins in the antiferromagnet and spins in the ferromagnet.

307

Depth Profile of Uncompensated Spins in an Exchange-Bias System  

NLE Websites -- All DOE Office Websites (Extended Search)

Depth Profile of Uncompensated Spins in an Exchange-Bias System Print Depth Profile of Uncompensated Spins in an Exchange-Bias System Print The phenomenon known as exchange bias at the interface between a ferromagnet and an antiferromagnet is currently a subject of intense research because of its applications in the magnetic recording and read-head industries. An international collaboration headed by researchers from the University of California, San Diego, has used resonant x-ray scattering and polarized-neutron reflectometry to determine the depth-dependent magnetization in an exchange-biased sample. These results provide atomic-level insights into the mechanism of exchange bias, specifically the involvement of mutual interactions between two kinds of uncompensated spins in the antiferromagnet and spins in the ferromagnet.

308

Depth Profile of Uncompensated Spins in an Exchange-Bias System  

NLE Websites -- All DOE Office Websites (Extended Search)

Depth Profile of Uncompensated Spins in an Exchange-Bias System Print Depth Profile of Uncompensated Spins in an Exchange-Bias System Print The phenomenon known as exchange bias at the interface between a ferromagnet and an antiferromagnet is currently a subject of intense research because of its applications in the magnetic recording and read-head industries. An international collaboration headed by researchers from the University of California, San Diego, has used resonant x-ray scattering and polarized-neutron reflectometry to determine the depth-dependent magnetization in an exchange-biased sample. These results provide atomic-level insights into the mechanism of exchange bias, specifically the involvement of mutual interactions between two kinds of uncompensated spins in the antiferromagnet and spins in the ferromagnet.

309

Neutronic Aspects and Recent Experimental Results with ...  

Science Conference Proceedings (OSTI)

... Neutronic Aspects and Recent Experimental Results with Methane Moderators at IUCF Low Energy Neutron Source (LENS). ...

310

Heteronuclear dipolar couplings, total spin coherence, and bilinear rotations in NMR spectroscopy  

SciTech Connect

In Chapter 1 a variety of different introductory topics are presented. The potential complexity of the nuclear magnetic resonsnace (NMR) spectra of molecules dissolved in liquid crystal solvents serves to motivate the development of multiple quantum (MQ) spectroscopy. The basics of MQ NMR are reviewed in Chapter 2. An experimental search procedure for the optimization of MQ pulse sequences is introduced. Chapter 3 discusses the application of MQ NMR techniques to the measurement of dipolar couplings in heteronuclear spin systems. The advantages of MQ methods in such systems are developed and experimental results for partially oriented (1-/sup 13/C) benzene are presented. Several pulse sequences are introduced which employ a two-step excitation of heteronuclear MQ coherence. A new multiple pulse method, involving the simultaneous irradiation of both rare and abundant spin species, is described. The problem of the broadening of MQ transitions due to magnetic field inhomogeneity is considered in Chapter 4. The method of total spin coherence transfer echo spectroscopy (TSCTES) is presented, with experimets on partially oriented acetaldehyde serving to demonstrate this new technique. TSCTES results in MQ spectra which are sensitive to all chemical shifts and spin-spin couplings and which are free of inhomogeneous broadening. In Chapter 5 the spectroscopy of spin systems of several protons and a /sup 13/C nucleus in the isotropic phase is discussed. The usefulness of the heteronuclear bilinear rotation as a calculational tool is illustrated. Compensated bilinear ..pi.. rotations, which are relatively insensitive to timing parameter missets, are presented. A new technique for homonuclear proton decoupling, Bilinear Rotation Decoupling, is described and its success in weakly coupled systems is demonstrated.

Garbow, J.R.

1983-07-01T23:59:59.000Z

311

Neutron Diffraction @ TOPAZ  

NLE Websites -- All DOE Office Websites (Extended Search)

Topaz Guide Bender Topaz Guide Bender Neutron Diffraction @ TOPAZ Workshop on Single Crystal Neutron Diffraction picture 2 September 29 - October 1, 2011 * Spallation Neutron Source * Oak Ridge National Laboratory * Oak Ridge TN, USA TOPAZ 2011 Home Contacts Agenda and Important Deadlines Registration and Payment filler Workshop summary and purpose A workshop on single crystal neutron diffraction will be held at the Spallation Neutron Source at the Oak Ridge National Laboratory (ORNL). It will present invited and contributed talks to showcase cutting edge science and examples where neutron diffraction can make significant contributions; and provide training in neutron structure analysis and sample screening for the preparation of instrument beam-time proposals. TOPAZ is a high resolution wavelength-resolved Laue diffractometer with a versatile sample environment. Commissioning user experiments have demonstrated successfully the instrument capability for structural study of a vitamin B12 derivative, ion distribution in Li-ion battery materials, order and disorder in shape memory intermetallics, magnetic phase transition in multiferroic single crystal and functional thin films. The workshop is directed towards experienced neutron diffraction users and new users alike and encourages members to highlight their research and interest in structure analysis and investigation. The workshop will give opportunity to bring your own single crystal and screen sample quality and scattering power on TOPAZ @ room temperature, to evaluate data collection time and quality for an anticipated experiment. Finally, an opportunity to compose a proposal for neutron beam time (http://neutrons.ornl.gov/users/proposals.shtml) with staff will be provided in the framework of the workshop. The workshop format is well suited for researchers to contribute by showcasing their research and bring their research group or graduate student, who would like to test a single crystal sample. User access training for the ORNL neutron scattering facility will be included. It will be valid for future experiments.

312

The Neutron Stars of Soft X-Ray Transients  

E-Print Network (OSTI)

Soft X-ray Transients (SXRTs) have long been suspected to contain old, weakly magnetic neutron stars that have been spun up by accretion torques. After reviewing their observational properties, we analyse the different regimes that likely characterise the neutron stars in these systems across the very large range of mass inflow rates, from the peak of the outbursts to the quiescent emission. While it is clear that close to the outburst maxima accretion onto the neutron star surface takes place, as the mass inflow rate decreases, accretion might stop at the magnetospheric boundary because of the centrifugal barrier provided by the neutron star. For low enough mass inflow rates (and sufficiently short rotation periods), the radio pulsar mechanism might turn on and sweep the inflowing matter away. The origin of the quiescent emission, observed in a number of SXRTs at a level of ~10^(32)-10^(33) erg/s, plays a crucial role in constraining the neutron star magnetic field and spin period. Accretion onto the neutron...

Campana, S; Mereghetti, S; Stella, L; Tavani, M

1998-01-01T23:59:59.000Z

313

NIST: NIF - Neutron Imaging Facility  

Science Conference Proceedings (OSTI)

... 1 above) is located at Beam Tube 2 (BT-2 ... Figure 2. Plan view of the neutron imaging facility ... still a significant amount of high energy neutrons and ...

314

Neutron and Nano User Meeting  

NLE Websites -- All DOE Office Websites (Extended Search)

Home Science @ Neutron and Nano Facilities User Workshops Integrated Agendas Venue Travel Information Contacts and Sponsors Registration Talks Neutron and Nano User Meeting August...

315

Neutron and Nano User Meeting  

NLE Websites -- All DOE Office Websites (Extended Search)

Science @ Neutron and Nano Facilities Science @ Neutron and Nano Facilities: Complementary Techniques Oak Ridge National Laboratory, Building 5200 Tuesday-Wednesday, August 13-14,...

316

News & Awards | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Awards Events and Conferences Supporting Organizations Neutron Science Home | Science & Discovery | Neutron Science | News and Awards SHARE News and Awards 1-6 of 6 Results...

317

Information coding of exciting laser pulses in an optical echo-processor  

SciTech Connect

We report the possibility of controlling the distribution of quantum bits within an inhomogeneously broadened line of a resonant transition in recording and transforming information in optical echo-processors. We consider the efficiency of realisation of the elementary logic XOR gate based on a two-pulse excitation of a resonant medium with phase memory. The encoded information is incorporated into the temporal shape of laser pulses in the form of amplitude modulation of an 'echelon' of present ('1') and absent ('0') pulse-codes for obtaining more efficient logic elements that reduce the noise in a quantum communication channel. (optical information processing)

Rusanova, I A [Kazan (Volga Region) Federal University, Kazan (Russian Federation)] [Kazan (Volga Region) Federal University, Kazan (Russian Federation)

2013-07-31T23:59:59.000Z

318

Single particle potentials of asymmetric nuclear matter in different spin-isospin channels  

E-Print Network (OSTI)

We investigate the neutron and proton single particle (s.p.) potentials of asymmetric nuclear matter and their isospin dependence in various spin-isospin $ST$ channels within the framework of the Brueckner-Hartree-Fock approach. It is shown that in symmetric nuclear matter, the s.p. potentials in both the isospin-singlet T=0 channel and isospin-triplet T=1 channel are essentially attractive, and the magnitudes in the two different channels are roughly the same. In neutron-rich nuclear matter, the isospin-splitting of the proton and neutron s.p. potentials turns out to be mainly determined by the isospin-singlet T=0 channel contribution which becomes more attractive for proton and more repulsive for neutron at higher asymmetries.

Wei Zuo; Sheng-Xin Gan; Umberto Lombardo

2013-10-04T23:59:59.000Z

319

Global-scale observations of changes in ionospheric echo occurrence and convection during periods of increased solar wind activity and increased geomagnetic activity .  

E-Print Network (OSTI)

??This thesis presents an investigation of ionospheric plasma convection and HF radar echoes during periods of enhanced geomagnetic activity. The work was split into two… (more)

Gillies, Deborah

2012-01-01T23:59:59.000Z

320

Spin Spectrometer at the ALS and APS  

E-Print Network (OSTI)

5 Spin Spectrometer at the ALS and APS-NIM/SRI07 Figure 3 Ancollected on Beamline 7 at the ALS is shown here. The photonSpin Spectrometer at the ALS and APS-NIM/SRI07 Spin

Tobin, James G; Lawrence Livermore National Laboratory; University of Missouri-Rolla; Boyd Technologies

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

FAST NEUTRON REACTOR  

DOE Patents (OSTI)

A reactor comprising fissionable material in concentration sufficiently high so that the average neutron enengy within the reactor is at least 25,000 ev is described. A natural uranium blanket surrounds the reactor, and a moderating reflector surrounds the blanket. The blanket is thick enough to substantially eliminate flow of neutrons from the reflector.

Soodak, H.; Wigner, E.P.

1961-07-25T23:59:59.000Z

322

Single spin asymmetries at CLAS  

DOE Green Energy (OSTI)

We present recent results from Jefferson Lab's CLAS detector on beam and target single-spin asymmetries in single pion electroproduction off unpolarized hydrogen and polarized NH 3 targets. Non-zero single-beam and single-target spin asymmetries are observed for the first time in semi-inclusive and exclusive pion production in hard-scattering kinematics.

Harut Avakian; Latifa Elouadrhiri

2003-05-19T23:59:59.000Z

323

Entanglement of dipolar coupling spins  

Science Conference Proceedings (OSTI)

Entanglement of dipole-dipole interacting spins 1/2 is usually investigated when the energy of interaction with an external magnetic field (the Zeeman energy) is greater than the energy of dipole interactions by three orders. Under this condition only ... Keywords: Dipolar interaction, Entanglement, Spin system

G. B. Furman; V. M. Meerovich; V. L. Sokolovsky

2011-06-01T23:59:59.000Z

324

Industry - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Industry and Neutron Science Industry and Neutron Science Industry and Neutron Science: Working To Make a Match "In fundamental research, we want to know everything. Industry wants to know enough to answer a question." Research Contact: Mike Crawford September 2011, Written by Deborah Counce Mike Crawford and Souleymane Diallo Mike Crawford of Dupont (right) and Souleymane Diallo, instrument scientist for the Backscattering Spectrometer at SNS, prepare a material sample for an experiment on the instrument. Industrial users are starting to eye the potential of neutron science for solving problems that can't be solved in any other way. At the same time, the SNS and HFIR neutron science facilities at ORNL are exploring ways to woo such users and to make a match of it, to the benefit of both.

325

Neutron Scattering Software  

NLE Websites -- All DOE Office Websites (Extended Search)

Software Software A new portal for neutron scattering has just been established at neutronsources.org. The information contained here in the Neutron Scattering Web has been transferred to the new site. We will leave the current content here for archival purposes but no new content will be added. We encourage everyone interested in neutron scattering to take full advantage of this exciting new resource for our community. Neutronsources.org Data Formats NeXus: Neutron and X-ray Data Format Crystallographic Binary Format (CBF/imgCIF) Hierarchical Data Format (HDF) Data Analysis and Visualization Data Analysis for Neutron Scattering Experiments (DANSE): distributed data analysis project Large Array Manipulation Program (LAMP): IDL-based data analysis and visualization

326

Pocked surface neutron detector  

DOE Patents (OSTI)

The detection efficiency, or sensitivity, of a neutron detector material such as of Si, SiC, amorphous Si, GaAs, or diamond is substantially increased by forming one or more cavities, or holes, in its surface. A neutron reactive material such as of elemental, or any compound of, .sup.10 B, .sup.6 Li, .sup.6 LiF, U, or Gd is deposited on the surface of the detector material so as to be disposed within the cavities therein. The portions of the neutron reactive material extending into the detector material substantially increase the probability of an energetic neutron reaction product in the form of a charged particle being directed into and detected by the neutron detector material.

McGregor, Douglas (Whitmore Lake, MI); Klann, Raymond (Bolingbrook, IL)

2003-04-08T23:59:59.000Z

327

THERMAL NEUTRON BACKSCATTER IMAGING.  

DOE Green Energy (OSTI)

Objects of various shapes, with some appreciable hydrogen content, were exposed to fast neutrons from a pulsed D-T generator, resulting in a partially-moderated spectrum of backscattered neutrons. The thermal component of the backscatter was used to form images of the objects by means of a coded aperture thermal neutron imaging system. Timing signals from the neutron generator were used to gate the detection system so as to record only events consistent with thermal neutrons traveling the distance between the target and the detector. It was shown that this time-of-flight method provided a significant improvement in image contrast compared to counting all events detected by the position-sensitive {sup 3}He proportional chamber used in the imager. The technique may have application in the detection and shape-determination of land mines, particularly non-metallic types.

VANIER,P.; FORMAN,L.; HUNTER,S.; HARRIS,E.; SMITH,G.

2004-10-16T23:59:59.000Z

328

Pulsed neutron detector  

DOE Patents (OSTI)

A pulsed neutron detector and system for detecting low intensity fast neutron pulses has a body of beryllium adjacent a body of hydrogenous material the latter of which acts as a beta particle detector, scintillator, and moderator. The fast neutrons (defined as having En>1.5 MeV) react in the beryllium and the hydrogenous material to produce larger numbers of slow neutrons than would be generated in the beryllium itself and which in the beryllium generate hellium-6 which decays and yields beta particles. The beta particles reach the hydrogenous material which scintillates to yield light of intensity related to the number of fast neutrons. A photomultiplier adjacent the hydrogenous material (scintillator) senses the light emission from the scintillator. Utilization means, such as a summing device, sums the pulses from the photo-multiplier for monitoring or other purposes.

Robertson, deceased, J. Craig (late of Albuquerque, NM); Rowland, Mark S. (Livermore, CA)

1989-03-21T23:59:59.000Z

329

SINGLE CRYSTAL NEUTRON DIFFRACTION.  

SciTech Connect

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.

KOETZLE,T.F.

2001-03-13T23:59:59.000Z

330

Recent Development in Proton Spin Physics  

E-Print Network (OSTI)

Development in Proton Spin Physics Feng YUAN [8] H. Jackson,investigations. These important physics, together with otherthat the transverse spin physics is playing a very important

Yuan, Feng

2009-01-01T23:59:59.000Z

331

Physics of solar neutron production: Questionable detection of neutrons  

E-Print Network (OSTI)

) A short introduction is given to astrophysics of neutron stars and to physics of dense matter in neutron stars. Observed properties of astro- physical objects containing neutron stars are discussed. Current scenarios regarding formation and evolution of neutron stars in those objects are presented. Physical

Share, Gerald

332

A Proof-of-Principle Echo-enabled Harmonic Generation Free Electron Laser Experiment at SLAC  

Science Conference Proceedings (OSTI)

With the advent of X-ray Free Electron Lasers (FELs), new methods have been developed to extend capabilities at short wavelengths beyond Self-Amplified Spontaneous Emission (SASE). In particular, seeding of a FEL allows for temporal control of the radiation pulse and increases the peak brightness by orders of magnitude. Most recently, Gennady Stupakov and colleagues at SLAC proposed a new technique: Echo-Enabled Harmonic Generation (EEHG). Here a laser microbunches the beam in an undulator and the beam is sheared in a chicane. This process is repeated with a second laser, undulator and chicane. The interplay between these allows a seeding of the X-ray laser up to the 100th harmonic of the first laser. After introducing the physics of FELs and the EEHG seeding technique, we describe contributions to the experimental effort. We will present detailed studies of the experiment including the choice of parameters and their optimization, the emittance effect, spontaneous emission in the undulators, the second laser phase effect, and measurements of the jitter between RF stations. Finally, the status and preliminary results of the Echo-7 experiment will be outlined.

Pernet, Pierre-Louis; /Ecole Polytechnique, Lausanne /SLAC

2012-01-06T23:59:59.000Z

333

Spin Splitting and Spin Current in Strained Bulk Semiconductors  

SciTech Connect

We present a theory for two recent experiments in bulk strained semiconductors and show that a new, previously overlooked, strain spin-orbit coupling term may play a fundamental role. We propose simple experiments that could clarify the origin of strain-induced spin-orbit coupling terms in inversion asymmetric semiconductors. We predict that a uniform magnetization parallel to the electric field will be induced in the samples studied in for specific directions of the applied electric field. We also propose special geometries to detect spin currents in strained semiconductors.

Bernevig, B.Andrei; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

2010-01-15T23:59:59.000Z

334

Excitations from a Bose-Einstein Condensate of Magnons in Coupled Spin Ladders  

SciTech Connect

The weakly coupled quasi-one-dimensional spin ladder compound CH32HHNH3CuCl3 is studied by neutron scattering in magnetic fields exceeding the critical field of Bose-Einstein condensation of magnons. Commensurate long-range order and the associated Goldstone mode are detected and found to be similar to those in reference to spin-dimer materials. However, for the upper two massive magnon branches, the observed behavior is totally different, culminating in a drastic collapse of excitation bandwidth beyond the transition point.

Garlea, Vasile O [ORNL; Zheludev, Andrey I [ORNL; Masuda, T. [Yokohama City University, Japan; Manaka, H. [Kagoshima University, Kagoshima JAPAN; Regnault, L.-P. [CEA, Grenoble, France; Ressouche, E. [CEA, Grenoble, France; Grenier, B. [CEA, Grenoble, France; Chung, J.-H. [National Institute of Standards and Technology (NIST); Qiu, Y. [National Institute of Standards and Technology (NIST); Habicht, Klaus [Hahn-Meitner Institut, Berlin, Germany; Kiefer, K. [Hahn-Meitner Institut, Berlin, Germany; Boehm, Martin [Institut Laue-Langevin (ILL)

2007-01-01T23:59:59.000Z

335

Versatile neutron NDA  

SciTech Connect

Non-destructive analysis (NDA) of bulk samples is a major tool in international safeguards and domestic MC&A. Yet, enhancements are needed to reduce inspection time, financial cost, and radiation exposure-while improving reliability and accuracy-particularly for mixtures of fissile and fertile isotopes. Perhaps the greatest remaining direction for NDA improvement is the development of a single controllable neutron source that would add versatility and capability. One of the primary prospects is a switchable radioactive neutron source (SRNS) that has been under advanced-concept development at Argonne with DOE funding. The SRNS would be in a sealed capsule that can be remotely switched on and off, or pulsed at a controllable rate. Li({alpha}, n) or Be({alpha}, n) reactions could give a choice of sub-threshold or hard-spectrum neutrons at yields ranging from 10{sup 4}/s to more than 10{sup 8}s. The SRNS would provide improved capabilities for (1) simultaneous or alternating interrogation with fast and slow neutrons, (2) detection of the first few seconds of delayed neutrons, (3) measurements in the presence of high neutron and/or gamma background, and (4) inspection of heterogeneous materials. When the neutrons are switched off, the source would be portable with vastly reduced shielding. Proof-of-concept with a single switchable plate has been established under laboratory conditions.

DeVolpi, A.

1995-07-01T23:59:59.000Z

336

Hypernuclear Physics for Neutron Stars  

E-Print Network (OSTI)

The role of hypernuclear physics for the physics of neutron stars is delineated. Hypernuclear potentials in dense matter control the hyperon composition of dense neutron star matter. The three-body interactions of nucleons and hyperons determine the stiffness of the neutron star equation of state and thereby the maximum neutron star mass. Two-body hyperon-nucleon and hyperon-hyperon interactions give rise to hyperon pairing which exponentially suppresses cooling of neutron stars via the direct hyperon URCA processes. Non-mesonic weak reactions with hyperons in dense neutron star matter govern the gravitational wave emissions due to the r-mode instability of rotating neutron stars.

Jurgen Schaffner-Bielich

2008-01-24T23:59:59.000Z

337

FABRICATION OF NEUTRON SOURCES  

DOE Patents (OSTI)

A method is presented for preparing a neutron source from polonium-210 and substances, such as beryllium and boron, characterized by emission of neutrons upon exposure to alpha particles from the polonium. According to the invention, a source is prepared by placing powdered beryllium and a platinum foil electroplated with polonium-2;.0 in a beryllium container. The container is sealed and then heated by induction to a temperature of 450 to 1100 deg C to volatilize the polonium off the foil into the powder. The heating step is terminated upon detection of a maximum in the neutron flux level.

Birden, J.H.

1959-04-21T23:59:59.000Z

338

Spin-manipulating polarized deuterons  

Science Conference Proceedings (OSTI)

Spin dynamics of polarized deuteron beams near depolarization resonances, including a new polarization preservation concept based on specially-designed multiple resonance crossings, has been tested in a series of experiments in the COSY synchrotron. Intricate spin dynamics with sophisticated pre-programmed patterns as well as effects of multiple crossings of a resonance were studied both theoretically and experimentally with excellent agreement. Possible applications of these results to preserve, manipulate and spin-flip polarized beams in synchrotrons and storage rings are discussed.

Morozov, V S; Krisch, A D; Leonova, M A; Raymond, R S; Sivers, D W; Wong, V K; Hinterberger, F; Kondratenko, A M

2011-03-01T23:59:59.000Z

339

Switchable radioactive neutron source device  

DOE Patents (OSTI)

This invention is a switchable neutron generating apparatus comprised of a pair of plates, the first plate having an alpha emitter section on it and the second plate having a target material portion on it which generates neutrons when its nuclei absorb an alpha particle. In operation, the alpha portion of the first plate is aligned with the neutron portion of the second plate to produce neutrons and brought out of alignment to cease production of neutrons. 3 figs.

Stanford, G.S.; Rhodes, E.A.; Devolpi, A.; Boyar, R.E.

1987-11-06T23:59:59.000Z

340

Preprint (December 8, 2012), to be published in the Eur. Phys. J. D. Multiple echoes due to distant dipolar fields in NMR of hyperpolarized  

E-Print Network (OSTI)

in solid 3 He, numerous experiments exploring the effects of distant dipolar fields in liquids have been rePreprint (December 8, 2012), to be published in the Eur. Phys. J. D. Multiple echoes due to distant temperatures as low as 10 mK for 129 Xe or 10 µK for 3 He, and the echoes originate from the distant dipolar

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Preprint (January 20, 2013), to be published in the Eur. Phys. J. D. Multiple echoes due to distant dipolar fields in NMR of hyperpolarized  

E-Print Network (OSTI)

in solid 3 He, numerous experiments exploring the effects of distant dipolar fields in liquids have been rePreprint (January 20, 2013), to be published in the Eur. Phys. J. D. Multiple echoes due to distant temperatures as low as 10 mK for 129 Xe or 10 µK for 3 He, and the echoes originate from the distant dipolar

Paris-Sud XI, Université de

342

Industry - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

PartTec PartTec ORNL, PartTec Inc. Licensing Agreement ORNL and PartTec sign licensing agreement (Front) ORNL Deputy Director for Science & Technology Thomas Zacharia and PartTec CEO Herschel Workman. (Back) Bruce Hannan (SNS), PartTec production manager Craig Kline, Rick Riedel (SNS), Jason Hodges (SNS) and Ron Cooper (SNS). The SNS guys were on the development team. Representatives from Oak Ridge National Laboratory and PartTec, an Indiana-based firm, formally signed a licensing agreement Thursday, Aug. 12, to market an advanced neutron detector system developed for the Spallation Neutron Source. The Shifting Scintillator Neutron Detector can determine the time and position of captured neutrons, which enables researchers to obtain very accurate time-of-flight measurements.

343

Education | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Education banner Education banner Sunil Sinha A Chat with Sunil Sinha, Distinguished Professor of Physics at the University of California-San Diego and speaker at the recent CNMS-SNS Research Forum more... The purpose of the Spallation Neutron Source and the High Flux Isotope Reactor is to facilitate neutron scattering as an integral tool for scientific research and technological development across many scientific and engineering domains within the scientific, academic,and industrial communities. Coupled with this role is a recognized need to inspire, educate, and facilitate the next generation of users and hence foster enhanced use of the unique neutron scattering facilities at ORNL. This is the central theme of the education activities within the Neutron Sciences Directorate (NScD).

344

ORNL Neutron Sciences Instruments  

NLE Websites -- All DOE Office Websites (Extended Search)

Instruments banner Instruments banner ORNL Neutron Sciences Instruments SNS and HFIR provide researchers with two complementary world-class suites of neutron scattering instruments and beam lines. All the instruments are supported by a variety of sample environments and data analysis and visualization capabilities. Before submitting a proposal for a specific instrument, please contact the appropriate instrument scientist to make sure your research is feasible for that instrument. Instruments Currently Available to Users SNS Beam Line Instrument Name HFIR Beam Line Instrument Name 1B NOMAD Nanoscale-Ordered Materials Diffractometer CG-1 Development Beam Line 2 BASIS Backscattering Spectrometer CG-1D IMAGING Neutron Imaging Prototype Facility 3 SNAP Spallation Neutrons and Pressure Diffractometer CG-2 GP-SANS

345

Awards | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

| Neutron Science | News and Awards | Awards SHARE Awards for Excellence 1-2 of 2 Results ORNL team wins R&D 100 award for wavelength-shifting scintillator detector January...

346

Personnel neutron dosimetry  

Science Conference Proceedings (OSTI)

This edited transcript of a presentation on personnel neutron discusses the accuracy of present dosimetry practices, requirements, calibration, dosemeter types, quality factors, operational problems, and dosimetry for a criticality accident. 32 figs. (ACR)

Hankins, D.

1982-04-01T23:59:59.000Z

347

Neutron personnel dosimetry  

Science Conference Proceedings (OSTI)

The current state-of-the-art in neutron personnel dosimetry is reviewed. Topics covered include dosimetry needs and alternatives, current dosimetry approaches, personnel monitoring devices, calibration strategies, and future developments. (ACR)

Griffith, R.V.

1981-06-16T23:59:59.000Z

348

Neutron Scattering Science User ...  

NLE Websites -- All DOE Office Websites (Extended Search)

Proposals for beam time at Oak Ridge National Laboratory's High Flux Isotope Reactor (HFIR) and Spallation Neutron Source (SNS) will be accepted via the web-based proposal system...

349

ORNL Neutron Sciences Users  

NLE Websites -- All DOE Office Websites (Extended Search)

SHUG banner SNS-HFIR User Group The SNS-HFIR User Group (SHUG) consists of all persons interested in using the neutron scattering facilities at Oak Ridge. It provides input to the...

350

Clifford G. Shull, Neutron Diffraction, Hydrogen Atoms, and Neutron  

Office of Scientific and Technical Information (OSTI)

Clifford Shull, Neutron Diffraction, and Neutron Scattering Clifford Shull, Neutron Diffraction, and Neutron Scattering Resources with Additional Information Clifford G. Shull was awarded the 1994 Nobel Prize in Physics "for the development of the neutron diffraction technique". 'Professor Shull's prize was awarded for his pioneering work in neutron scattering, a technique that reveals where atoms are within a material like ricocheting bullets reveal where obstacles are in the dark. Clifford Shull Photo Courtesy of Oak Ridge National Laboratory When a beam of neutrons is directed at a given material, the neutrons bounce off, or are scattered by, atoms in the sample being investigated. The neutrons' directions change, depending on the location of the atoms they hit, and a diffraction pattern of the atoms' positions can then be obtained.

351

Inelastic neutron scattering in valence fluctuation compounds  

SciTech Connect

The valence fluctuation compounds are rare earth intermetallics where hybridization of the nearly-localized 4f electrons with the conduction electrons leads to incorporation of the 4f's into the itinerant states. This hybridization slows down the conduction electrons and hence gives them a heavy effective mass, justifying application of the term 'heavy Fermion' (HF) to these materials. During the project period, we grew large single crystals of several such compounds and measured their properties using both standard thermodynamic probes and state-of-the-art inelastic neutron scattering. We obtained three main results. For the intermediate valence compounds CePd{sub 3} and YbAl{sub 3}, we showed that the scattering of neutrons by the fluctuations of the 4f magnetic moment does not have the momentum dependence expected for the itinerant heavy mass state; rather, the scattering is more typical of a localized spin fluctuation. We believe that incoherent scattering localizes the excitation. For the heavy Fermion compound Ce(Ni{sub 0.935}Pd{sub 0.065}){sub 2}Ge{sub 2}, which sits at a T = 0 critical point for transformation into an antiferromagnetic (AF) phase, we showed that the scattering from the AF fluctuations does not exhibit any of the divergences that are expected at a phase transition. We speculate that alloy disorder profoundly suppresses the growth of the fluctuating AF regions, leading to short range clusters rather than regions of infinite size. Finally, we explored the applicability of key concepts used to describe the behavior of rare earth heavy Fermions to uranium based HF compounds where the 5f electrons are itinerant as opposed to localized. We found that scaling laws relating the spin fluctuation energy measured in neutron scattering to the low temperature specific heat and susceptibility are valid for the uranium compounds, once corrections are made for AF fluctuations; however, the degeneracy of the high temperature moment is smaller than expected for rare-earth-like Hund's rule behavior, essentially because the orbital moment is suppressed for itinerant 5f electrons. We also found that the standard local-moment-based theory of the temperature dependence of the specific heat, susceptibility and neutron scattering fails badly for URu{sub 2}Zn{sub 20} and UCo{sub 2}Zn{sub 20}, even though the theory is phenomenally successful for the closely related rare earth compound YbFe{sub 2}Zn{sub 20}. Both these results highlight the distinction between the itineracy of the 5f's and the localization of the 4f's. It is our hope that these results are sufficiently significant as to stimulate deeper investigation of these compounds.

Jon M Lawrence

2011-02-15T23:59:59.000Z

352

Spinning angle optical calibration apparatus  

DOE Patents (OSTI)

An optical calibration apparatus is provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting an accurate reproducing of spinning "magic angles" in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the "magic angle" of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to a graduation or graduations on a reticle in the magnifying scope is noted. Thereafter, the spinning "magic angle" of a test material having similar nuclear properties to the standard is attained by returning the sample holder back to the originally noted coordinate position.

Beer, Stephen K. (Morgantown, WV); Pratt, II, Harold R. (Morgantown, WV)

1991-01-01T23:59:59.000Z

353

Spinning angle optical calibration apparatus  

DOE Patents (OSTI)

An optical calibration apparatus is provided for calibrating and reproducing spinning angles in cross-polarization, nuclear magnetic resonance spectroscopy. An illuminated magnifying apparatus enables optical setting and accurate reproducing of spinning magic angles in cross-polarization, nuclear magnetic resonance spectroscopy experiments. A reference mark scribed on an edge of a spinning angle test sample holder is illuminated by a light source and viewed through a magnifying scope. When the magic angle of a sample material used as a standard is attained by varying the angular position of the sample holder, the coordinate position of the reference mark relative to a graduation or graduations on a reticle in the magnifying scope is noted. Thereafter, the spinning magic angle of a test material having similar nuclear properties to the standard is attained by returning the sample holder back to the originally noted coordinate position. 2 figs.

Beer, S.K.; Pratt, H.R. II.

1989-09-12T23:59:59.000Z

354

NEUTRON FLUX INTENSITY DETECTION  

DOE Patents (OSTI)

A method of measuring the instantaneous intensity of neutron flux in the core of a nuclear reactor is described. A target gas capable of being transmuted by neutron bombardment to a product having a resonance absorption line nt a particular microwave frequency is passed through the core of the reactor. Frequency-modulated microwave energy is passed through the target gas and the attenuation of the energy due to the formation of the transmuted product is measured. (AEC)

Russell, J.T.

1964-04-21T23:59:59.000Z

355

FABRICATION OF NEUTRON SOURCES  

DOE Patents (OSTI)

A method is presented for preparing a more efficient neutron source comprising inserting in a container a quantity of Po-210, inserting B powder coated with either Ag, Pt, or Ni. The container is sealed and then slowly heated to about 450 C to volatilize the Po and effect combination of the coated powder with the Po. The neutron flux emitted by the unit is moritored and the heating step is terminated when the flux reaches a maximum or selected level.

Birden, J.H.

1959-01-20T23:59:59.000Z

356

Facilities and Capabilities | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Isotope Reactor and the Spallation Neutron Source. The continuous neutron source at HFIR and the pulsed neutron source at SNS complement each other well and, along with their...

357

Science Education Programs | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

What are Neutrons Why Research with Neutrons Graduate & Post-doctoral Programs Student & Teacher Programs Science Forum Neutron Scattering Tutorials Kids' Corner News and Awards...

358

ORNL Neutron Sciences Directorate Executive Office  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Sciences Directorate Executive Office Kelly Beierschmitt ORNL Associate Laboratory Director for Neutron Sciences Kelly Beierschmitt. The Neutron Sciences Directorate (NScD)...

359

Switched Control of Electron Nuclear Spin Systems  

E-Print Network (OSTI)

In this article, we study control of electron-nuclear spin dynamics at magnetic field strengths where the Larmor frequency of the nucleus is comparable to the hyperfine coupling strength. The quantization axis for the nuclear spin differs from the static B_0 field direction and depends on the state of the electron spin. The quantization axis can be switched by flipping the state of electron spin, allowing for universal control on nuclear spin states. We show that by performing a sequence of flips (each followed by a suitable delay), we can perform any desired rotation on the nuclear spins, which can also be conditioned on the state of the electron spin. These operations, combined with electron spin rotations can be used to synthesize any unitary transformation on the coupled electron-nuclear spin system. We discuss how these methods can be used for design of experiments for transfer of polarization from the electron to the nuclear spins.

Navin Khaneja

2007-07-11T23:59:59.000Z

360

Two Wien Filter Spin Flipper  

SciTech Connect

A new 4pi spin manipulator composed of two Wien filters oriented orthogonally and separated by two solenoids has been installed at the CEBAF/Jefferson Lab photoinjector. The new spin manipulator is used to precisely set the electron spin direction at an experiment in any direction (in or out of plane of the accelerator) and provides the means to reverse, or flip, the helicity of the electron beam on a daily basis. This reversal is being employed to suppress systematic false asymmetries that can jeopardize challenging parity violation experiments that strive to measure increasingly small physics asymmetries [*,**,***]. The spin manipulator is part of the ultra-high vacuum polarized electron source beam line and has been successfully operated with 100keV and 130keV electron beam at high current (>100 microAmps). A unique feature of the device is that spin-flipping requires only the polarity of one solenoid magnet be changed. Performance characteristics of the Two Wien Filter Spin Flipper will be summarized.

Grames, J M; Benesch, J F; Clark, J; Hansknecht, J; Kazimi, R; Machie, D; Poelker, M; Stutzman, M L; Suleiman, R

2011-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Microsoft Word - CX-Echo Lake-Monroe Spacers_WEB.doc  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

17, 2010 17, 2010 REPLY TO ATTN OF: KEPR-4 SUBJECT: Environmental Clearance Memorandum Corinn Castro Project Manager - TELM-TPP-3 Proposed Action: Spacer-damper replacements on the Echo Lake-Monroe No. 1 500-kV transmission line Budget Information: Work Order # 00255064 PP&A Project No.: 1514 Categorical Exclusion Applied (from Subpart D, 10 C.F.R. Part 1021): B1.3, Routine maintenance activities for structures, rights-of-way, and infrastructures, (such as roads), that are required to maintain infrastructures in a condition suitable for a facility to be used for its designed purpose. Location: The project is in King and Snohomish counties, Washington in Bonneville Power Administration's (BPA) North Region, Covington and Snohomish districts. Townships,

362

Spatially Addressable Readout and Erasure of an Image in a Gradient Echo Memory  

E-Print Network (OSTI)

We show that portions of an image written into a gradient echo memory can be individually retrieved or erased on demand, an important step towards processing a spatially multiplexed quantum signal. Targeted retrieval is achieved by locally addressing the transverse plane of the storage medium, a warm 85Rb vapor, with a far-detuned control beam. Spatially addressable erasure is similarly implemented by imaging a bright beam tuned near the 85Rb D1 line in order to scatter photons and induce decoherence. Under our experimental conditions atomic diffusion is shown to impose an upper bound on the effective spatial capacity of the memory. The decoherence induced by the optical eraser is characterized and modeled as the response of a two level atom in the presence of a strong driving field.

Jeremy B. Clark; Quentin Glorieux; Paul D. Lett

2013-02-19T23:59:59.000Z

363

Scalable time reversal of Raman echo quantum memory and quantum waveform conversion of light pulse  

E-Print Network (OSTI)

We have found the new hidden symmetry of time reversal light-atom interaction in the photon echo quantum memory with Raman atomic transition. The time-reversed quantum memory provides generalized condition for ideal compression/decompression of time duration and wavelength conversion of the input light pulse. Based on a general analytical approach to this scheme, we have studied the optimal conditions of the light field compression/decompression in resonant atomic systems characterized by realistic spectral properties. The demonstrated effective quantum conversion of the light waveform and wavelength are also discussed for various possible realizations of the quantum memory scheme. The performed study promises new capabilities for fundamental study of the light-atom interaction and for deterministic quantum manipulation of the light field interested for quantum communication and quantum computing.

Moiseev, E S

2013-01-01T23:59:59.000Z

364

High Winds Generated by Bow Echoes. Part II: The Relationship between the Mesovortices and Damaging Straight-Line Winds  

Science Conference Proceedings (OSTI)

Airborne radar analysis of a mesovortex that developed near the apex of a bow echo is presented. The mesovortex was shown to play a critical role in determining the location of intense “straight-line” wind damage at the surface. The perturbation ...

Roger M. Wakimoto; Hanne V. Murphey; Christopher A. Davis; Nolan T. Atkins

2006-10-01T23:59:59.000Z

365

Investigating the Potential of Using Radar Echo Reflectivity to Nowcast Cloud-to-Ground Lightning Initiation over Southern Ontario  

Science Conference Proceedings (OSTI)

The potential for using radar echo reflectivity to forecast cloud-to-ground (CG) lightning initiation in the 0–1-h time frame was investigated in southern Ontario, Canada. The main purpose of this investigation was to determine a reflectivity ...

Y. Helen Yang; Patrick King

2010-08-01T23:59:59.000Z

366

VOLUME 67, NUMBER 1 PHYSICAL REVIEW LETTERS 1 JULY 1991 Optically Induced Coherence Transfer Echoes between Zeeman Substates  

E-Print Network (OSTI)

between Zeeman Substates Dieter Suter and Martin Rosatzin Institute of Quantum Electronics, Swiss Federal-echo phenomena associated with Zeeman coherences in a sublevel manifold. The experiments on the ground state on the Zeeman sublevels of the 3s `S'r,z ground state of atomic sodium. The beam of a single-mode cw ring dye

Suter, Dieter

367

Using an Army of Inverted Echo Sounders to Measure Dynamic Height and Geostrophic Current in the North Pacific Subtropical Gyre  

Science Conference Proceedings (OSTI)

In 1991, an array of five inverted echo sounders (IESs) was deployed about 100 km north of the island of Oahu, Hawaii, as part of the World Ocean Circulation Experiment deep-water station. IESs record the round-trip acoustic travel time from the ...

Stephen M. Chiswell

1994-10-01T23:59:59.000Z

368

Development of the OSO-6 high-energy neutron detector and correlation of measured solar neutron fluxes to solar flares  

SciTech Connect

Thesis. The development of a directional high energy (20 to 160 MeV) neutron detector which was flown to satellite altitudes (500 km; circular equatorial orbit) in the NASA Orbiting Solar Observatory (OSO-6) in August 1969 is described. Both the angle of incidence and the energy of the neutron are determined by a proton-recoil telescope (Pilot B scintillation plastic) which provides the source for proton-recoils and defines the dE/dX versus E method for particle identification and energy determination. The telescope is embedded in a scintillation plastic guard counter envelope which eliminates the unwanted charged particle background as well as recoil protons (electrons) whose energies and direction do not satisfy neutron (gamma-ray) detection requirements, respectively. Results from a Monte Carlo calculation indicate that the overall average efficiency within an average angular acceptance of about 29 deg (FWHM) is approximately (2.25 plus or minus 0.113) x 10/sup -4/. The inflight calibration procedure, the main frame data bit error analysis, and the method for determining the orientation of the detector axis in the spacecraft spin plane are described. Results indicate a discrepancy in the measured (0.461 x 10/sup -2/ plus or minus 0.254 x 10/sup -2/ n/cm/sup 2/sec) and theoretical (2 to 70 n/cm/ sup 2/sec) neutron flux es which suggests a lack of basic underatanding of mechanisms leading to high energy neutron production at the sun. (auth)

Young, F.

1974-02-01T23:59:59.000Z

369

Applications of MRI in Fluidics: Single Echo Acquisition MRI Toward Microfluidics  

E-Print Network (OSTI)

Microscale devices capable of manipulating fluids have potential to give rise to a paradigm shift in the fields of biology and medicine. The purpose of this research is to assess the feasibility of applying single echo acquisition (SEA) magnetic resonance imaging (MRI) to microscale fluid flow quantification. This is important because development and improvement of microfluidic devices requires the ability to accurately and non-invasively measure microscale flow. Lab-on-a-chip aims to integrate an array of chemical laboratory tools onto a single chip, utilizing microfluidic flow for mass transport. Use of microfluidics results in improved speed and efficiency and allows operations that harness physical properties unique to the microscale. Current microscale flow visualization methods rely on fluorescence, requiring optically non-opaque fluids and device boundaries. Furthermore, these methods require insertion of labeled chemicals or seed particles into the flow, which may interfere with processes under observation. MRI has an established history of non-invasively quantifying flow through opaque boundaries but is limited by its slow image acquisition rate. SEA employs a 64-channel array coil to acquire a full image with each echo, significantly improving temporal resolution. Methods involve assessing the performance of SEA flow velocimetry on a scale of several millimeters by utilizing time-of-flight techniques. By taking a series of 5 ms snapshots, quantitative velocity information is obtained for laminar, transitional, and turbulent flow with Reynolds numbers ranging from 100 to 1200. Findings show that the turbulent eddies are visible and velocity information can be extracted from images, which means that SEA can accurately asses flow at the millimeter scale. In addition, SEA allows visualization of turbulent flow not accessible to standard MRI velocimetry techniques. It is concluded that SEA could be adapted as new tool for non-invasive quantification of optically inaccessible flow. Implications of this are that through integrated radio frequency microcoils, SEA MRI could be adapted as a new tool to study microfluidic flow resulting in improved microfluidic devices.

Bosshard, John

2006-08-16T23:59:59.000Z

370

Neutron lifetime measurements using gravitationally trapped ultracold neutrons  

E-Print Network (OSTI)

Our experiment using gravitationally trapped ultracold neutrons (UCN) to measure the neutron lifetime is reviewed. Ultracold neutrons were trapped in a material bottle covered with perfluoropolyether. The neutron lifetime was deduced from comparison of UCN losses in the traps with different surface-to-volume ratios. The precise value of the neutron lifetime is of fundamental importance to particle physics and cosmology. In this experiment, the UCN storage time is brought closer to the neutron lifetime than in any experiments before:the probability of UCN losses from the trap was only 1% of that for neutron beta decay. The neutron lifetime obtained,878.5+/-0.7stat+/-0.3sys s, is the most accurate experimental measurement to date.

A. P. Serebrov; V. E. Varlamov; A. G. Kharitonov; A. K. Fomin; Yu. N. Pokotilovski; P. Geltenbort; I. A. Krasnoschekova; M. S. Lasakov; R. R. Taldaev; A. V. Vassiljev; O. M. Zherebtsov

2007-02-06T23:59:59.000Z

371

Skyrme-Random-Phase-Approximation description of spin-flip and orbital giant resonances  

E-Print Network (OSTI)

The self-consistent separable random-phase approximation (SRPA) model with Skyrme forces is extended to the case of magnetic excitations and applied to the description of spin-flip and orbital M1 giant resonances in the isotopic chain $^{142-152}$Nd. The Skyrme forces SkT6, SkM*, SLy6 and SkI3 are used. The calculations show the onset of the scissors mode with increasing deformation. A specific three-peak structure of the spin-flip response is found and explained by particular neutron and proton spin-flip transitions. Although the employed forces provide an acceptable qualitative description, the Skyrme functional still needs further improvement to reproduce quantitatively the experimental data.

V. O. Nesterenko; J. Kvasil; P. Vesely; W. Kleinig; P. -G. Reinhard

2009-11-12T23:59:59.000Z

372

Spin hall effect in paramagnetic thin films  

E-Print Network (OSTI)

Spintronics, an abbreviation of spin based electronics and also known as magneto electronics, has attracted a lot of interest in recent years. It aims to explore the role of electrons’ spins in building next generation electric devices. Using electrons’ spins rather than electrons’ charges may allow faster, lower energy cost devices. Spin Hall Effect is an important subfield of spintronics. It studies spin current, spin transport, and spin accumulation in paramagnetic systems. It can further understanding of quantum physics, device physics, and may also provide insights for spin injection, spin detection and spin manipulation in the design of the next generation spintronics devices. In this experimental work, two sets of experiments were prepared to detect the Spin Hall Effect in metallic systems. The first set of experiments aims to extract Spin Hall Effect from Double Hall Effect in micrometer size metal thin film patterns. Our experiments proved that the Spin Hall Effect signal was much smaller than the theoretically calculated value due to higher electrical resistivity in evaporated thin films. The second set of experiments employs a multi-step process. It combines micro fabrication and electrochemical method to fabricate a perpendicular ferromagnet rod as a spin injector. Process description and various techniques to improve the measurement sensitivity are presented. Measurement results in aluminum, gold and copper are presented in Chapters III, IV and V. Some new experiments are suggested in Chapters V and VI.

Xu, Huachun

2008-12-01T23:59:59.000Z

373

GALLIUM ARSENIDE SEMICONDUCTOR-BASED NEUTRON DETECTOR  

NEUTRON DETECTOR BENEFITS Portable, ... High Flux Isotope Reactor and Spallation Neutron Source. Several Homeland Security. LINKS TO ONLINE ...

374

Portable Neutron Sensors for Emergency Response Operations  

Science Conference Proceedings (OSTI)

This slide-show presents neutron measurement work, including design, use and performance of different neutron detection systems.

Mukhopadhyay, S., Maurer, R., Detweiler, R.

2012-06-22T23:59:59.000Z

375

Detection and Control of Individual Nuclear Spins Using a Weakly Coupled Electron Spin  

Science Conference Proceedings (OSTI)

We experimentally isolate, characterize, and coherently control up to six individual nuclear spins that are weakly coupled to an electron spin in diamond. Our method employs multipulse sequences on the electron spin that resonantly amplify the interaction with a selected nuclear spin and at the same time dynamically suppress decoherence caused by the rest of the spin bath. We are able to address nuclear spins with interaction strengths that are an order of magnitude smaller than the electron spin dephasing rate. Our results provide a route towards tomography with single-nuclear-spin sensitivity and greatly extend the number of available quantum bits for quantum information processing in diamond.

Taminiau, T.H.; Wagenaar, J.J.T.; van der Sar, T.; Jelezko, F.; Dobrovitski, Viatcheslav V.; Hanson, R.

2012-09-28T23:59:59.000Z

376

Nano-Signals Get a Boost from Magnetic Spin Waves  

Science Conference Proceedings (OSTI)

Nano-Signals Get a Boost from Magnetic Spin Waves. ... Electrical measurement of spin-wave interactions of proximate spin transfer nano-oscillators. ...

2011-04-26T23:59:59.000Z

377

Classically spinning and isospinning solitons  

SciTech Connect

We investigate classically spinning topological solitons in (2+1)- and (3+1)-dimensional models; more explicitely spinning sigma model solitons in 2+1 dimensions and Skyrme solitons in 2+1 and 3+1 dimensions. For example, such types of solitons can be used to describe quasiparticle excitations in ferromagnetic quantum Hall systems or to model spin and isospin states of nuclei. The standard way to obtain solitons with quantised spin and isospin is the semiclassical quantization procedure: One parametrizes the zero-mode space - the space of energy-degenerate soliton configurations generated from a single soliton by spatial translations and rotations in space and isospace - by collective coordinates which are then taken to be time-dependent. This gives rise to additional dynamical terms in the Hamiltonian which can then be quantized following semiclassical quantization rules. A simplification which is often made in the literature is to apply a simple adiabatic approximation to the (iso)rotational zero modes of the soliton by assuming that the soliton's shape is rotational frequency independent. Our numerical results on classically spinning arbitrarily deforming soliton solutions clearly show that soliton deformation cannot be ignored.

Battye, Richard A.; Haberichter, Mareike [Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester M13 9PL (United Kingdom)

2012-09-26T23:59:59.000Z

378

Hestenes' Tetrad and Spin Connections  

E-Print Network (OSTI)

Defining a spin connection is necessary for formulating Dirac's bispinor equation in a curved space-time. Hestenes has shown that a bispinor field is equivalent to an orthonormal tetrad of vector fields together with a complex scalar field. In this paper, we show that using Hestenes' tetrad for the spin connection in a Riemannian space-time leads to a Yang-Mills formulation of the Dirac Lagrangian in which the bispinor field is mapped to a set of Yang-Mills gauge potentials and a complex scalar field. This result was previously proved for a Minkowski space-time using Fierz identities. As an application we derive several different non-Riemannian spin connections found in the literature directly from an arbitrary linear connection acting on Hestenes' tetrad and scalar fields. We also derive spin connections for which Dirac's bispinor equation is form invariant. Previous work has not considered form invariance of the Dirac equation as a criterion for defining a general spin connection.

Frank Reifler; Randall Morris

2007-06-08T23:59:59.000Z

379

Neutron beam characterization at the Neutron Radiography Reactor (NRAD)  

Science Conference Proceedings (OSTI)

The Neutron Radiography Reactor (NRAD) is a 250-kW TRIGA Reactor operated by Argonne National Laboratory and is located near Idaho Falls, Idaho. The reactor and its facilities regarding radiography are detailed in another paper at this conference; this paper summarizes neutron flux measurements and calculations that have been performed to better understand and potentially improve the neutronics characteristics of the reactor.

Imel, G.R.; Urbatsch, T.; Pruett, D.P.; Ross, J.R.

1990-01-01T23:59:59.000Z

380

Theoretical study of a localized quantum spin reversal by the sequential injection of spins in a spin quantum dot  

E-Print Network (OSTI)

This is a theoretical study of the reversal of a localized quantum spin induced by sequential injection of spins for a spin quantum dot that has a quantum spin. The system consists of ``electrode/quantum well(QW)/dot/QW/electrode" junctions, in which the left QW has an energy level of conduction electrons with only up-spin. We consider a situation in which up-spin electrons are sequentially injected from the left electrode into the dot through the QW and an exchange interaction acts between the electrons and the localized spin. To describe the sequentially injected electrons, we propose a simple method based on approximate solutions from the time-dependent Schr$\\ddot{\\rm o}$dinger equation. Using this method, it is shown that the spin reversal occurs when the right QW has energy levels of conduction electrons with only down-spin. In particular, the expression of the reversal time of a localized spin is derived and the upper and lower limits of the time are clearly expressed. This expression is expected to be useful for a rough estimation of the minimum relaxation time of the localized spin to achieve the reversal. We also obtain analytic expressions for the expectation value of the localized spin and the electrical current as a function of time. In addition, we found that a system with the non-magnetic right QW exhibits spin reversal or non-reversal depending on the exchange interaction.

Satoshi Kokado; Kazumasa Ueda; Kikuo Harigaya; Akimasa Sakuma

2007-08-10T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
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381

Industry - ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Former User Group Chair Enthusiastic About Relevance of Neutron Scattering Former User Group Chair Enthusiastic About Relevance of Neutron Scattering to Industrial Research Former User Group Chair Mike Crawford Mike Crawford, DuPont Research and Development. The drive is intensifying to encourage research partnerships between Neutron Sciences and private industry. Such partnerships, a long-term strategic goal set by the DOE's Basic Energy Sciences Advisory Committee, will deliver industry and its technological problems to SNS and HFIR, where joint laboratory-industry teams can use the unparalleled resources available here to resolve them. "SNS is a tremendous facility. It has the potential to have a couple of thousand user visits a year and, if they build another target station in the future, you're probably talking about 4000 user visits a year,"

382

Contacts | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Points of Contact Science Points of Contact Name Research Area Doug Abernathy Wide Angular-Range Chopper Spectrometer (ARCS). Atomic-scale dynamics at thermal and epithermal energies Ke An Engineering Materials Diffractometer (VULCAN). Residual stress, deformation mechanism of materials, phase transitions/transformation, and in situ/operando neutron diffraction in material systems (e.g., working batteries). John Ankner Liquids Reflectometer (LR). Density profiles normal to the surface at liquid surfaces and liquid interfaces Bryan Chakoumakos Nuclear and magnetic crystal structure systematics and structure-property relationships among inorganic materials, powder and single-crystal neutron and x-ray diffraction methods Leighton Coates Macromolecular Neutron Diffractometer (MaNDi). Protein crystallography, biological structure and function

383

Neutron Scattering Conference Archive  

NLE Websites -- All DOE Office Websites (Extended Search)

Conference Archive Conference Archive A new portal for neutron scattering has just been established at neutronsources.org. The information contained here in the Neutron Scattering Web has been transferred to the new site. We will leave the current content here for archival purposes but no new content will be added. We encourage everyone interested in neutron scattering to take full advantage of this exciting new resource for our community. Neutronsources.org 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 2000 June 12-14, 2000 Workshop on "New Opportunities for Better User Group Software (NOBUGS III)" Location Daresbury Laboratory, Cheshire, UK Contact Mark Enderby, Daresbury Laboratory Email M.J.Enderby@dl.ac.uk URL http://nobugs.dl.ac.uk/

384

METHOD OF PRODUCING NEUTRONS  

DOE Patents (OSTI)

A method for producing neutrons is described in which there is employed a confinement zone defined between longitudinally spaced localized gradient regions of an elongated magnetic field. Changed particles and neutralizing electrons, more specifically deuterons and tritons and neutralizng electrons, are injected into the confinement field from ion sources located outside the field. The rotational energy of the parrticles is increased at the gradients by imposing an oscillating transverse electrical field thereacross. The imposition of such oscillating transverse electrical fields improves the reflection capability of such gradient fielda so that the reactive particles are retained more effectively within the zone. With the attainment of appropriate densities of plasma particles and provided that such particles are at a sufficiently high temperature, neutron-producing reactions ensue and large quantities of neutrons emerge from the containment zone. (AEC)

Imhoff, D.H.; Harker, W.H.

1964-02-01T23:59:59.000Z

385

Ultrafast neutron detector  

DOE Patents (OSTI)

The invention comprises a neutron detector (50) of very high temporal resolution that is particularly well suited for measuring the fusion reaction neutrons produced by laser-driven inertial confinement fusion targets. The detector comprises a biased two-conductor traveling-wave transmission line (54, 56, 58, 68) having a uranium cathode (60) and a phosphor anode (62) as respective parts of the two conductors. A charge line and Auston switch assembly (70, 72, 74) launch an electric field pulse along the transmission line. Neutrons striking the uranium cathode at a location where the field pulse is passing, are enabled to strike the phosphor anode and produce light that is recorded on photographic film (64). The transmission line may be variously configured to achieve specific experimental goals.

Wang, Ching L. (Livermore, CA)

1987-01-01T23:59:59.000Z

386

Personnel electronic neutron dosimeter  

DOE Patents (OSTI)

A personnel electronic dosimeter includes a neutron-proton and neutron-alpha converter for providing an electrical signal having a magnitude proportional to the energy of a detected proton or alpha particle produced from the converter, a pulse generator circuit for generating a pulse having a duration controlled by the weighed effect of the amplitude of the electrical signal, an oscillator enabled by the pulse for generating a train of clock pulses for a time dependent upon the pulse length, a counter for counting the clock pulses, and an indicator for providing a direct reading and aural alarm when the count indicates that the wearer has been exposed to a selected level of neutron dose equivalent.

Falk, R.B.; Tyree, W.H.

1982-03-03T23:59:59.000Z

387

Corrosion resistant neutron absorbing coatings  

SciTech Connect

A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

Choi, Jor-Shan (El Cerrito, CA); Farmer, Joseph C. (Tracy, CA); Lee, Chuck K. (Hayward, CA); Walker, Jeffrey (Gaithersburg, MD); Russell, Paige (Las Vegas, NV); Kirkwood, Jon (Saint Leonard, MD); Yang, Nancy (Lafayette, CA); Champagne, Victor (Oxford, PA)

2012-05-29T23:59:59.000Z

388

Neutron tubes - Energy Innovation Portal  

A neutron generating target is positioned so that the ion beam is ... Electricity Transmission; Energy Analysis; Energy Storage; Geothermal; Hydrogen ...

389

Research Highlights | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnetic Spin Behavior in Iron Magnetic Spin Behavior in Iron Telluride ARCS maps collaborative magnetic spin behavior in iron telluride Local, itinerant spins collaborate, boosting magnetism with temperature Research Contact: Igor Zaliznyak Dec. 2011, Written by Agatha Bardoel Researchers have long thought that magnetism and superconductivity are mutually exclusive. The former typically involves localized atomic electrons. The latter requires freely propagating, itinerant electrons. That magnetism and high-temperature superconductivity (HTSC) are mutually exclusive was challenged by the recent discovery of antiferromagnetic phases in parent materials of both HTSC cuprates and iron pnictides and chalcogenides. Antiferromagnetism is a form of magnetic ordering in which the spins of the

390

GUIDE FOR POLARIZED NEUTRONS  

DOE Patents (OSTI)

The plane of polarization of a beam of polarized neutrons is changed by this invention, and the plane can be flipped back and forth quicitly in two directions in a trouble-free manner. The invention comprises a guide having a plurality of oppositely directed magnets forming a gap for the neutron beam and the gaps are spaced longitudinally in a spiral along the beam at small stepped angles. When it is desired to flip the plane of polarization the magnets are suitably rotated to change the direction of the spiral of the gaps. (AEC)

Sailor, V.L.; Aichroth, R.W.

1962-12-01T23:59:59.000Z

391

FAST NEUTRONIC REACTOR  

DOE Patents (OSTI)

This patent relates to a reactor and process for carrying out a controlled fast neutron chain reaction. A cubical reactive mass, weighing at least 920 metric tons, of uranium metal containing predominantly U/sup 238/ and having a U/sup 235/ content of at least 7.63% is assembled and the maximum neutron reproduction ratio is limited to not substantially over 1.01 by insertion and removal of a varying amount of boron, the reactive mass being substantially freed of moderator.

Snell, A.H.

1957-12-01T23:59:59.000Z

392

Fast neutron dosimetry  

Science Conference Proceedings (OSTI)

This progress report concentrates on two major areas of dosimetry research: measurement of fast neutron kerma factors for several elements for monochromatic and white spectrum neutron fields and determination of the response of thermoluminescent phosphors to various ultra-soft X-ray energies and beta-rays. Dr. Zhixin Zhou from the Shanghai Institute of Radiation Medicine, People's Republic of China brought with him special expertise in the fabrication and use of ultra-thin TLD materials. Such materials are not available in the USA. The rather unique properties of these materials were investigated during this grant period.

DeLuca, P.M. Jr.; Pearson, D.W.

1992-01-01T23:59:59.000Z

393

Publications from Research Conducted at MR | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Publications from Research Conducted at MR Publications from Research Conducted at MR 2013 Publications Erickson M. J., "Surface and interface effects in nanoscopic metallic spin transport devices", University of Minnesota , (2013). Ji N., Lauter V., Zhang X., Ambaye H., Wang J.-P., "Strain induced giant magnetism in epitaxial Fe16N2 thin film", Applied Physics Letters 102, 072411 (2013). Jiang C. Y., Tong X., Brown D. R., Lee W. T., Ambaye H., Craig J. W., Crow L., Culbertson H., Goyette R., Graves-Brook M. K., Hagen M. E., Kadron B., Lauter V., McCollum L. W., Robertson J. L., Winn B., Vandegrift A. E., "Polarized 3He neutron spin filters at Oak Ridge National Laboratory", Physics Procedia 42, 191-199 (2013). Ke X., Belenky L. J., Lauter V., Ambaye H., Bark C. W., Eom C. B.,

394

Top Quark Spin Correlations - Theory  

Science Conference Proceedings (OSTI)

The top quark decay width (G{sub F}m{sub t}{sup 3} {approx} 1 GeV) is much larger than the QCD hadronization scale ({Lambda}{sub QCD} {approx} 0.1 GeV) and much larger than the spin decorrelation scale ({Lambda}{sub QCD}{sup 2}/m{sub t} {approx} 0.1 MeV). Therefore, spin correlations in top quark pair production are reflected in angular correlations of the decay products, see [1] and [2].

Parke, Stephen J.; /Fermilab

2012-02-01T23:59:59.000Z

395

Software Model Checking with SPIN  

E-Print Network (OSTI)

The aim of this chapter is to give an overview ofthe theoretical foundation and the practical application of logic model checking techniques for the verification of multi-threaded software (rather than hardware) systems. The treatment is focused on the logic model checker SPIN, which was designed for this specific domain of application. SPIN implements an automata-theoretic method of verification. Although the tool has been available for over 15years, it continues to ev olve, adopting new optimization strategies from time to time to help it tackle larger verification problems. This chapter explains how the tool works, and

Gerard J. Holzmann

2005-01-01T23:59:59.000Z

396

COMMISSIONING SPIN ROTATORS IN RHIC.  

Science Conference Proceedings (OSTI)

During the summer of 2002, eight superconducting helical spin rotators were installed into RHIC in order to control the polarization directions independently at the STAR and PHENIX experiments. Without the rotators, the orientation of polarization at the interaction points would only be vertical. With four rotators around each of the two experiments, we can rotate either or both beams from vertical into the horizontal plane through the interaction region and then back to vertical on the other side. This allows independent control for each beam with vertical, longitudinal, or radial polarization at the experiment. In this paper, we present results from the first run using the new spin rotators at PHENIX.

Mackay, W W; Bai, M; Courant, E D; Fischer, W; Huang, H; Luccio, A; Montag, C; Pilat, F; Ptitsyn, V; Roser, T; Satogata, T; Trbojevic, D

2003-05-12T23:59:59.000Z

397

Kangley - Echo Lake Transmission Line Project Supplemental Draft Environmental Impact Statement  

SciTech Connect

Bonneville Power Administration (BPA) is proposing to build a new transmission line to accommodate increasing demand for electricity and address reliability concerns in the Puget Sound area. The Proposed Action would construct a new line that would connect to an existing transmission line near the community of Kangley, and then connect with BPA's existing Echo Lake Substation. The major purpose of this proposal is to improve system reliability in the King County area. An outage on an existing line during times of heavy use, such as during a winter cold snap, could cause voltage instability and a loss of power in the King County area. System planners have projected total system load using normal growth in demand and determined that system instability could develop as early as the winter of 2002-03. Besides meeting this need for system reliability, this project would enhance the United States' delivery of power to Canada as required under the Columbia River Treaty of 1961. BPA described and analyzed transmission route alternatives in a draft environmental impact statement (DEIS) released in June 2001. The DEIS identified a preferred alternative that would parallel an existing BPA transmission line through the Cedar River Municipal Watershed. BPA received over 700 comments from landowners, agencies, tribes and special interest groups on the DEIS. Many of the comments suggested BPA re-evaluate the range of alternatives considered and prepare a supplemental draft environmental impact statement (SDEIS). After reviewing the comments and refining the cost estimates associated with BPA's preferred alternative, BPA decided to prepare this SDEIS to re-evaluate alternatives not analyzed in detail in the DEIS. The added transmission alternatives, all located outside of the Cedar River Watershed, were initially considered but dropped from detailed analysis. They are identified as Alternatives A, B, C, and D. Alternatives A and C are located to the west of the Cedar River Watershed boundary. Alternatives B and D cross the Mt. Baker-Snoqualmie and Okanogan-Wenatchee National Forests. Under all transmission alternatives, Echo Lake Substation would be expanded about three acres to the east and new equipment to accommodate the new line would be installed. BPA is also considering a Non-Transmission Alternative and the No Action Alternative.

N /A

2003-01-10T23:59:59.000Z

398

Transport of polarized neutrons through magnetic noncoplanar layered systems  

SciTech Connect

The transport of neutrons through noncoplanar systems is shown to have a partly unidirectional character. To this end, the transmission of a three-layer magnetic film with a noncoplanar magnetization in the absence of applied magnetic field and the transmission of a two-layer magnetic film with a noncollinear magnetization in the presence of a magnetic field are calculated. The calculations demonstrate that, if the losses in the films are neglected, the transmissions in two opposite directions differ only for processes with and without spin flip. If these losses are taken into account, the total transmissions of a nonpolarized neutron beam in two opposite directions are also different. The consequences of these specific features of noncoplanar systems are discussed.

Ignatovich, V. K., E-mail: ignatovi@gmail.com; Nikitenko, Yu. V. [Joint Institute for Nuclear Research, Laboratory of Neutron Physics (Russian Federation); Fraerman, A. A. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)

2010-05-15T23:59:59.000Z

399

Neutron and Synchrotron X-Ray Scattering Studies of Superconductors  

Science Conference Proceedings (OSTI)

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

Tranquada,J.M.

2008-09-01T23:59:59.000Z

400

Neutron-unbound states in {sup 25,26}F  

Science Conference Proceedings (OSTI)

Neutron-unbound states in {sup 25}F and {sup 26}F were populated via the reactions {sup 9}Be({sup 26}Ne,{sup 24}F + n) and {sup 9}Be({sup 26}Ne,{sup 25}F + n), respectively. A resonance close to the neutron separation energy in {sup 25}F was identified with a decay energy of 28{+-}4 keV. This resonance corresponds to an excited state in {sup 25}F at 4249{+-}116 keV assuming it decays to the ground state of {sup 24}F. Guided by shell-model calculations, a spin and parity of 1/2{sup -} can be assigned to this state. In the spectrum of {sup 26}F, which was produced in a nucleon-exchange reaction, there are indications for an excited state with a decay energy of {approx}270 keV.

Frank, N. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics and Astronomy, Augustana College, Rock Island, Illinois 61201 (United States); Albertson, D.; Luther, B. [Department of Physics, Concordia College, Moorhead, Minnesota 56562 (United States); Bailey, J.; Kasperczyk, M.; Smith, A. [Physics Department, Illinois Wesleyan University, Bloomington, Illinois 61701 (United States); Baumann, T.; Bazin, D.; Schiller, A. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Brown, B. A.; Gade, A.; Peters, W. A.; Thoennessen, M. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Brown, J. [Department of Physics, Wabash College, Crawfordsville, Indiana 47933 (United States); DeYoung, P. A. [Department of Physics, Hope College, Holland, Michigan 49423 (United States); Finck, J. E. [Department of Physics, Central Michigan University, Mt. Pleasant, Michigan 48859 (United States); Hinnefeld, J. [Department of Physics and Astronomy, Indiana University at South Bend, South Bend, Indiana 46634 (United States); Howes, R. [Department of Physics, Marquette University, Milwaukee, Wisconsin 53201 (United States); Tostevin, J. A. [Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

2011-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Spin tracking in RHIC (Code Spink)  

SciTech Connect

The evolution of the spin during acceleration in the Relativistic Heavy Ion Collider (RHIC) has been studied with a new numerical code, Spink. Results of spin tracking through resonances are shown.

Luccio, A.U.

1995-12-31T23:59:59.000Z

402

Control of single spin in Markovian environment  

E-Print Network (OSTI)

In this article we study the control of single spin in Markovian environment. Given an initial state, we compute all the possible states to which the spin can be driven at arbitrary time, under the assumption that fast ...

Yuan, Haidong

403

Efficient Spin Injection using Tunnel Injectors  

Science Conference Proceedings (OSTI)

Semiconductor spintronics aims to develop novel sensor, memory and logic devices by manipulating the spin states of carriers in semiconducting materials. This talk will focus on electrical spin injection into semiconductors, which is a prerequisite for ...

Xin Jiang

2005-07-01T23:59:59.000Z

404

Nucleon spin physics at Jefferson Lab  

Science Conference Proceedings (OSTI)

In this talk I shall review some of the important results from the spin physics program at JLab and give an outlook for the 12 GeV upgrade spin program.

Zein-Eddine Meziani

2006-06-05T23:59:59.000Z

405

Spin liquids, exotic phases and phase transitions  

E-Print Network (OSTI)

Spin liquid, or featureless Mott-Insulator, is a theoretical state of matter firstly motivated from study on High-Tc superconductor. The most striking property of spin liquids is that they do not break any physical symmetry, ...

Ran, Ying

2007-01-01T23:59:59.000Z

406

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

Science Conference Proceedings (OSTI)

New, more efficient materials for spin valves - a device used in magnetic sensors, random access memories, and hard disk drives - may be on the way based on research using the magnetism reflectometer at Oak Ridge National Laboratory (ORNL). Spin valve devices work by means of two or more conducting magnetic material layers that alternate their electrical resistance depending on the layers alignment. Giant magnetoresistance is a quantum mechanical effect first observed in thin film structures about 20 years ago. The effect is observed as a significant change in electrical resistance, depending on whether the magnetization of adjacent ferromagnetic layers is in a parallel or an antiparallel magnetic alignment. 'What we are doing here is developing new materials. The search for new materials suitable for injecting and transferring carriers with a preferential spin orientation is most important for the development of spintronics,' said Valeria Lauter, lead instrument scientist on the magnetism reflectometer at the Spallation Neutron Source (SNS), who collaborated on the experiment. The researchers discovered that the conductivity of such materials is improved when an organic polymer semiconductor layer is placed between the magnetic materials. Organic semiconductors are now the material of choice for future spin valve devices because they preserve spin coherence over longer times and distances than conventional semiconductors. While research into spin valves has been ongoing, research into organic semiconductors is recent. Previous research has shown that a 'conductivity mismatch' exists in spin valve systems in which ferromagnetic metal electrodes interface with such organic semiconductors as Alq3 ({pi}-conjugated molecule tris(8-hydroxy-quinoline) aluminium). This mismatch limits the efficient injection of the electrons from the electrodes at the interface with the semiconductor material. However, lithium fluoride (LiF), commonly used in light-emitting diodes, has been found to enhance the injection of electrons through the semiconductor. Researchers from the University of Alabama and ORNL used polarized neutrons at the magnetism reflectometer at SNS to investigate the electronic, magnetic, and structural properties of the electrodes in a novel system. In this system, the magnetic layers cobalt and Ni{sub 80}Fe{sub 20} are interfaced with spacer layers composed of the organic semiconductor Alq3. A coupling layer of LiF is inserted to separate the magnetized layers from the semiconductor. 'ALQ3 is an organic semiconductor material,' said Lauter. 'Normally in these systems a first magnetic layer is grown on a hard substrate so that one can get the controlled magnetic parameters. Then you grow the organic semiconductor layer, followed by another magnetic material layer, such as cobalt.' In addition to determining the effect of the LiF layers on the efficiency of the electron injection, the researchers wanted to determine the magnetic properties of the cobalt and Ni{sub 80}Fe{sub 20} as well as the interfacial properties: whether there is interdiffusion of cobalt through the LiF layer to the semiconductor, for example. The researchers used polarized neutrons at beam line 4A to probe the entire, layer-by-layer assembly of the system. 'Reflectometry with polarized neutrons is a perfect method to study thin magnetic films,' Lauter said. 'These thin films - if you put one on a substrate, you see it just like a mirror. However, this mirror has a very complicated internal multilayer structure. The neutrons look inside this complicated structure and characterize each and every interface. Due to the depth sensitivity of the method, we measure the structural and magnetic properties of each layer with the resolution of 0.5 nm. The neutron scattering results found that inserting LiF as a barrier significantly improves the quality of the interface, increasing the injection of electrons from the magnetic layer through the organic semiconductor in the spin valve and enhancing the overall properties of the system. In related work the magneti

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

2012-01-01T23:59:59.000Z

407

Neutron Absorbing Alloys  

SciTech Connect

The present invention is drawn to new classes of advanced neutron absorbing structural materials for use in spent nuclear fuel applications requiring structural strength, weldability, and long term corrosion resistance. Particularly, an austenitic stainless steel alloy containing gadolinium and less than 5% of a ferrite content is disclosed. Additionally, a nickel-based alloy containing gadolinium and greater than 50% nickel is also disclosed.

Mizia, Ronald E. (Idaho Falls, ID); Shaber, Eric L. (Idaho Falls, ID); DuPont, John N. (Whitehall, PA); Robino, Charles V. (Albuquerque, NM); Williams, David B. (Bethlehem, PA)

2004-05-04T23:59:59.000Z

408

Neutronic reactor thermal shield  

DOE Patents (OSTI)

1. The method of operating a water-cooled neutronic reactor having a graphite moderator which comprises flowing a gaseous mixture of carbon dioxide and helium, in which the helium comprises 40-60 volume percent of the mixture, in contact with the graphite moderator.

Wende, Charles W. J. (West Chester, PA)

1976-06-15T23:59:59.000Z

409

Neutron Science User Program  

E-Print Network (OSTI)

provides a user gateway for SNS and HFIR 11 Managed by UT-Battelle for the U.S. Department of Energy #12.) · Complementary to SNS HFIR produces the world's highest thermal neutron flux #12;13 UT-Battelle Department infrastructure (REDC, HFIR, etc.): $3B+ national asset ORNL is uniquely positioned to support advanced nuclear

410

NEUTRONIC REACTOR STRUCTURE  

DOE Patents (OSTI)

A neutronic reactor is described. It has a core consisting of natural uranium and heavy water and having a K-factor greater than unity which is surrounded by a reflector consisting of natural uranium and ordinary water having a Kfactor less than unity.

Weinberg, A.M.; Vernon, H.C.

1961-05-30T23:59:59.000Z

411

NEUTRONIC REACTOR STRUCTURE  

DOE Patents (OSTI)

The neutronic reactor is comprised of a core consisting of natural uranium and heavy water with a K-factor greater than unity. The core is surrounded by a reflector consisting of natural uranium and ordinary water with a Kfactor less than unity. (AEC)

Vernon, H.C.; Weinberg, A.M.

1961-05-30T23:59:59.000Z

412

NEUTRONIC REACTOR CONTROL ELEMENT  

DOE Patents (OSTI)

A boron-10 containing reactor control element wherein the boron-10 is dispersed in a matrix material is describeri. The concentration of boron-10 in the matrix varies transversely across the element from a minimum at the surface to a maximum at the center of the element, prior to exposure to neutrons. (AEC)

Beaver, R.J.; Leitten, C.F. Jr.

1962-04-17T23:59:59.000Z

413

Neutron proton crystallography station (PCS)  

SciTech Connect

The PCS (Protein Crystallography Station) at Los Alamos Neutron Science Center (LANSCE) is a unique facility in the USA that is designed and optimized for detecting and collecting neutron diffraction data from macromolecular crystals. PCS utilizes the 20 Hz spallation neutron source at LANSCE to enable time-of-flight measurements using 0.6-7.0 {angstrom} neutrons. This increases the neutron flux on the sample by using a wavelength range that is optimal for studying macromolecular crystal structures. The diagram below show a schematic of PCS and photos of the detector and instrument cave.

Fisher, Zoe [Los Alamos National Laboratory; Kovalevsky, Andrey [Los Alamos National Laboratory; Johnson, Hannah [Los Alamos National Laboratory; Mustyakimov, Marat [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

414

Electron Correlation and the Nuclear Spin—Spin Coupling Constant. I. An Alternant Molecular Orbital Description of Nuclear Spin—Spin Coupling  

Science Conference Proceedings (OSTI)

A theoretical description of contact nuclear spin—spin coupling is presented in terms of the density?matrix formalism and the approximation of an ``average excitation energy''. For a molecular system in a singlet state the density of spin coupling is proportional to the difference between the correlation functions for electrons of the same and opposite spins. Application of the one?parameter alternant molecular orbital (AMO) method

Michael Barfield

1966-01-01T23:59:59.000Z

415

SNAP: the Spallation Neutrons and Pressure Diffractometer at...  

NLE Websites -- All DOE Office Websites (Extended Search)

Spallation Neutrons and Pressure Diffractometer at SNS Spallation Neutrons and Pressure Diffractometer. Spallation Neutrons and Pressure Diffractometer. The SNAP Diffractometer...

416

Deeply virtual Compton scattering on longitudinally polarized protons and neutrons at CLAS  

Science Conference Proceedings (OSTI)

This paper focuses on a measurement of deeply virtual Compton scattering (DVCS) performed at Jefferson Lab using a nearly-6-GeV polarized electron beam, two longitudinally polarized (via DNP) solid targets of protons (NH{sub 3}) and deuterons (ND{sub 3}) and the CEBAF Large Acceptance Spectrometer. Here, preliminary results for target-spin asymmetries and double (beam-target) asymmetries for proton DVCS, as well as a very preliminary extraction of beam-spin asymmetry for neutron DVCS, are presented and linked to Generalized Parton Distributions.

Silvia Niccolai

2012-04-01T23:59:59.000Z

417

Spin-forming Project Report  

Science Conference Proceedings (OSTI)

In a second development order, spin-forming equipment was again evaluated using the test shape, a hemispherical shell. In this second development order, pure vanadium and alloy titanium (Ti-6Al-4V) were spin-formed, as well as additional copper and 21-6-9 stainless. In the first development order the following materials had been spin-formed: copper (alloy C11000 ETP), 6061 aluminum, 304L stainless steel, 21-6-9 stainless steel, and tantalum-2.5% tungsten. Significant challenges included properly adjusting the rotations-per-minute (RPM), cracking at un-beveled edges and laser marks, redressing of notches, surface cracking, non-uniform temperature evolution in the titanium, and cracking of the tailstock. Lessons learned were that 300 RPM worked better than 600 RPM for most materials (at the feed rate of 800 mm/min); beveling the edges to lower the stress reduces edge cracking; notches, laser marks, or edge defects in the preform doom the process to cracking and failure; coolant is required for vanadium spin-forming; increasing the number of passes to nine or more eliminates surface cracking for vanadium; titanium develops a hot zone in front of the rollers; and the tailstock should be redesigned to eliminate the cylindrical stress concentrator in the center.

Switzner, Nathan; Henry, Dick

2009-03-20T23:59:59.000Z

418

DIRECT CONFIRMATION OF THE ASYMMETRY OF THE CAS A SUPERNOVA WITH LIGHT ECHOES  

SciTech Connect

We report the first detection of asymmetry in a supernova (SN) photosphere based on SN light echo (LE) spectra of Cas A from the different perspectives of dust concentrations on its LE ellipsoid. New LEs are reported based on difference images, and optical spectra of these LEs are analyzed and compared. After properly accounting for the effects of finite dust-filament extent and inclination, we find one field where the He I {lambda}5876 and H{alpha} features are blueshifted by an additional {approx}4000 km s{sup -1} relative to other spectra and to the spectra of the Type IIb SN 1993J. That same direction does not show any shift relative to other Cas A LE spectra in the Ca II near-infrared triplet feature. We compare the perspectives of the Cas A LE dust concentrations with recent three-dimensional modeling of the SN remnant (SNR) and note that the location having the blueshifted He I and H{alpha} features is roughly in the direction of an Fe-rich outflow and in the opposite direction of the motion of the compact object at the center of the SNR. We conclude that Cas A was an intrinsically asymmetric SN. Future LE spectroscopy of this object, and of other historical SNe, will provide additional insight into the connection of the explosion mechanism to SN then to SNR, as well as give crucial observational evidence regarding how stars explode.

Rest, A.; Narayan, G. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, MA 02138 (United States); Foley, R. J.; Kirshner, R. P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Sinnott, B.; Welch, D. L. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Badenes, C. [Benoziyo Center for Astrophysics, Faculty of Physics, Weizmann Institute of Science, 76100 Rehovot (Israel); Filippenko, A. V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Bergmann, M. [6530 E. Clinton St., Scottsdale, AZ 85254 (United States); Bhatti, W. A.; Huber, M. E. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, 3400 North Charles Street, MD 21218 (United States); Blondin, S. [Centre de Physique des Particules de Marseille (CPPM), Aix-Marseille Universite, CNRS/IN2P3, 163 Avenue de Luminy, 13288 Marseille Cedex 9 (France); Challis, P.; Damke, G. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Finley, H. [Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Kasen, D. [UCO/Lick Observatory, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 (United States); Matheson, T. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719-4933 (United States); Mazzali, P. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Strasse 1, 85741 Garching (Germany); Minniti, D. [Vatican Observatory, V00120 Vatican City State (Italy); Nakajima, R., E-mail: marcelbergmann@gmail.com [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States)

2011-05-01T23:59:59.000Z

419

Spin Transport and Relaxation in Graphene and Germanium  

E-Print Network (OSTI)

transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fig. 1-8, electrical spin transport in Si . . . . . . . . .21 Chapter 2: Theoretical view of spin transport and

Han, Wei

2011-01-01T23:59:59.000Z

420

SNS | Spallation Neutron Source | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

SNS SNS Instruments Working with SNS Contact Us User Program Manager Laura Morris Edwards 865.574.2966 Spallation Neutron Source Home | User Facilities | SNS SNS | Spallation Neutron Source SHARE SNS is an accelerator-based neutron source in Oak Ridge, Tennessee, USA. This one-of-a-kind facility provides the most intense pulsed neutron beams in the world for scientific research and industrial development. The 80-acre SNS site is located on Chestnut Ridge and is part of Oak Ridge National Laboratory. Although most people don't know it, neutron scattering research has a lot to do with our everyday lives. For example, things like medicine, food, electronics, and cars and airplanes have all been improved by neutron scattering research. Neutron research also helps scientists improve materials used in a

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Coated Fiber Neutron Detector Test  

Science Conference Proceedings (OSTI)

Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. The currently deployed radiation portal monitors (RPMs) from Ludlum and Science Applications International Corporation (SAIC) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large neutron detector. There is a declining supply of 3He in the world, and thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Reported here are the results of tests of the 6Li/ZnS(Ag)-coated non-scintillating plastic fibers option. This testing measured the required performance for neutron detection efficiency and gamma ray rejection capabilities of a system manufactured by Innovative American Technology (IAT).

Lintereur, Azaree T.; Ely, James H.; Kouzes, Richard T.; Stromswold, David C.

2009-10-23T23:59:59.000Z

422

Bonneville Power Administration Kangley-Echo Lake Transmission Line Project Record of Decision (DOE/EIS-0317) (7/21/03)  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Bonneville Power Administration Bonneville Power Administration Kangley-Echo Lake Transmission Line Project Record of Decision Decision The Bonneville Power Administration (BPA) has decided to construct the proposed Kangley-Echo Lake Transmission Line Project in King County, Washington. BPA has decided to implement the Proposed Action (Alternative 1) identified in the Kangley-Echo Lake Transmission Line Project Final Environmental Impact Statement (DOE/EIS-0317-S1, June 2003). This decision is made thirty (30) days after publication of the notice for a final EIS (June 20, 2003) in the Federal Register. The Proposed Action consists of constructing a new 500-kilovolt (kV) transmission line from a tap point on an existing 500-kV line near Kangley, Washington, to BPA's Echo Lake

423

An Exact SU(2) Symmetry and Persistent Spin Helix ina Spin-orbit Coupled System  

SciTech Connect

Spin-orbit coupled systems generally break the spin rotation symmetry. However, for a model with equal Rashba and Dresselhauss coupling constant (the ReD model), and for the [110] Dresselhauss model, a new type of SU(2) spin rotation symmetry is discovered. This symmetry is robust against spin-independent disorder and interactions, and is generated by operators whose wavevector depends on the coupling strength. It renders the spin lifetime infinite at this wavevector, giving rise to a Persistent Spin Helix (PSH). We obtain the spin fluctuation dynamics at, and away, from the symmetry point, and suggest experiments to observe the PSH.

Bernevig, B.A.; /Stanford U., Phys. Dept. /Santa Barbara, KITP; Orenstein, J.; /LBL, Berkeley /UC, Berkeley; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

2007-01-22T23:59:59.000Z

424

An Exact SU(2) Symmetry and Persistent Spin Helix in a Spin-Orbit Coupled System  

SciTech Connect

Spin-orbit coupled systems generally break the spin rotation symmetry. However, for a model with equal Rashba and Dresselhauss coupling constant (the ReD model), and for the [110] Dresselhauss model, a new type of SU(2) spin rotation symmetry is discovered. This symmetry is robust against spin-independent disorder and interactions, and is generated by operators whose wavevector depends on the coupling strength. It renders the spin lifetime infinite at this wavevector, giving rise to a Persistent Spin Helix (PSH). We obtain the spin fluctuation dynamics at, and away, from the symmetry point, and suggest experiments to observe the PSH.

Bernevig, Andrei

2010-02-10T23:59:59.000Z

425

LENDA, a Low Energy Neutron Detector Array for experiments with radioactive beams in inverse kinematics  

E-Print Network (OSTI)

The Low Energy Neutron Detector Array (LENDA) is a neutron time-of-flight (TOF) spectrometer developed at the National Superconducting Cyclotron Lab- oratory (NSCL) for use in inverse kinematics experiments with rare isotope beams. Its design has been motivated by the need to study the spin-isospin response of unstable nuclei using (p, n) charge-exchange reactions at intermediate energies (> 100 MeV/u). It can be used, however, for any reaction study that involves emission of low energy neutrons (150 keV - 10 MeV). The array consists of 24 plastic scintillator bars and is capable of registering the recoiling neutron energy and angle with high detection efficiency. The neutron energy is determined by the time-of-flight technique, while the position of interaction is deduced using the timing and energy information from the two photomultipliers of each bar. A simple test setup utilizing radioactive sources has been used to characterize the array. Results of test measurements are compared with simulations. A neutron energy threshold of 20 % for neutrons below 4 MeV have been obtained.

G. Perdikakis; M. Sasano; Sam M. Austin; D. Bazin; C. Caesar; S. Cannon; J. M. Deaven; H. J. Doster; C. J. Guess; G. W. Hitt; J. Marks; R. Meharchand; D. T. Nguyen; D. Peterman; A. Prinke; M. Scott; Y. Shimbara; K. Thorne; L. Valdez; R. G. T. Zegers

2011-11-17T23:59:59.000Z

426

Characterizing Exoplanets in the Visible and Infrared: A Spectrometer Concept for the EChO Space Mission  

E-Print Network (OSTI)

Transit-spectroscopy of exoplanets is one of the key observational techniques to characterize the extrasolar planet and its atmosphere. The observational challenges of these measurements require dedicated instrumentation and only the space environment allows an undisturbed access to earth-like atmospheric features such as water or carbon-dioxide. Therefore, several exoplanet-specific space missions are currently being studied. One of them is EChO, the Exoplanet Characterization Observatory, which is part of ESA's Cosmic Vision 2015-2025 program, and which is one of four candidates for the M3 launch slot in 2024. In this paper we present the results of our assessment study of the EChO spectrometer, the only science instrument onboard this spacecraft. The instrument is a multi-channel all-reflective dispersive spectrometer, covering the wavelength range from 400 nm to 16 microns simultaneously with a moderately low spectral resolution. We illustrate how the key technical challenge of the EChO mission - the high...

Glauser, A M; Krause, O; Henning, Th; Benneke, B; Bouwman, J; Cubillos, P E; Crossfield, I J M; Detre, Ö H; Ebert, M; Grözinger, U; Güdel, M; Harrington, J; Justtanont, K; Klaas, U; Lenzen, R; Madhusudhan, N; Meyer, M R; Mordasini, C; Müller, F; Ottensamer, R; Plesseria, J -Y; Quanz, S P; Reiners, A; Renotte, E; Rohloff, R -R; Scheithauer, S; Schmid, H M; Schrader, J -R; Seemann, U; Stam, D; Vandenbussche, B; Wehmeier, U

2013-01-01T23:59:59.000Z

427

Continued Evaluation of the Pulse-Echo Ultrasonic Instrument for Critical Velocity Determination during Hanford Tank Waste Transfer Operations  

Science Conference Proceedings (OSTI)

Laboratory (PNNL) conducted an extensive evaluation of the ability of three ultrasonic instruments to detect critical velocity for a broad range of simulated Hanford nuclear waste streams containing particles with mean particle sizes of >50 microns. Evaluations were perform using the pipe loop at the Process Development Laboratory – East (PDL-E) at PNNL that was designed and built to evaluate the pipeline plugging issue during slurry transfer operations at the Hanford Waste Treatment Plant. In 2011 the ability of the ultrasonic PulseEcho system to detect critical velocity continued to be evaluated using the PDL-E flow loop and new simulants containing high-density particles with a mean particle size of < 15 microns. The PDL-E flow loop was modified for the 2011 testing to include a new test section that contained 5-MHz and 10-MHz ultrasonic transducers non-invasively mounted to schedule 40 pipe. The test section also contained reference instrumentation to facilitate direct comparison of the real-time PulseEcho transducer responses with experimentally observed critical velocities. This paper presents the results from the 2011 PulseEcho evaluation using a variety of simulated Hanford nuclear waste streams that were selected to encompass the expected high-level waste feed properties.

Denslow, Kayte M.; Bontha, Jagannadha R.; Adkins, Harold E.; Jenks, Jeromy WJ; Burns, Carolyn A.; Schonewill, Philip P.; Hopkins, Derek F.; Thien, Michael G.; Wooley, Theodore A.

2012-04-01T23:59:59.000Z

428

Skyrme-Rpa Description of Spin-Flip M1 Giant Resonance  

E-Print Network (OSTI)

The spin-flip M1 giant resonance is explored in the framework of Random Phase Approximation on the basis of the Skyrme energy functional. A representative set of eight Skyrme parameterizations (SkT6, SkM*, SLy6, SG2, SkO, SkO', SkI4, and SV-bas) is used. Light and heavy, spherical and deformed nuclei ($^{48}$Ca, $^{158}$Gd, $^{208}$Pb, and $^{238}$U) are considered. The calculations show that spin densities play a crucial role in forming the collective shift in the spectrum. The interplay of the collective shift and spin-orbit splitting determines the quality of the description. None of the considered Skyrme parameterizations is able to describe simultaneously the M1 strength distribution in closed-shell and open-shell nuclei. It is found that the problem lies in the relative positions of proton and neutron spin-orbit splitting. Necessity to involve the tensor and isovector spin-orbit interaction is called for.

P. Vesely; J. Kvasil; V. O. Nesterenko; W. Kleinig; P. -G. Reinhard; V. Yu. Ponomarev

2009-07-06T23:59:59.000Z

429

Transverse target spin asymmetry in inclusive DIS with two-photon exchange  

SciTech Connect

We study the transverse target spin dependence of the cross section for the inclusive electron-nucleon scattering with unpolarized beam. Such dependence is absent in the one-photon exchange approximation (Christ-Lee theorem) and arises only in higher orders of the QED expansion, from the interference of one-photon and absorptive two-photon exchange amplitudes as well as from real photon emission (bremsstrahlung). We demonstrate that the transverse spin-dependent two-photon exchange cross section is free of QED infrared and collinear divergences. We argue that in DIS kinematics the transverse spin dependence should be governed by a "parton-like" mechanism in which the two-photon exchange couples mainly to a single quark. We calculate the normal spin asymmetry in an approximation where the dominant contribution arises from quark helicity flip due to interactions with non-perturbative vacuum fields (constituent quark picture) and is proportional to the quark transversity distribution in the nucleon. Such helicity-flip processes are not significantly Sudakov-suppressed if the infrared scale for gluon emission in the photon-quark subprocess is of the order of the chiral symmetry breaking scale, mu^2_chiral>>Lambda^2_QCD. We estimate the asymmetry in the kinematics of the planned Jefferson Lab Hall A experiment to be of the order 10^-4, with different sign for proton and neutron. We also comment on the spin dependence in the limit of soft high-energy scattering.

Andrei Afanasev; Mark Strikman; Christian Weiss

2007-09-06T23:59:59.000Z

430

Skyrme random-phase-approximation description of spin-flip M1 giant resonance  

SciTech Connect

The spin-flip M1 giant resonance is explored in the framework of the random-phase-approximation (RPA) on the basis of the Skyrme energy functional. A representative set of eight Skyrme parametrizations (SkT6, SkM*, SLy6, SG2, SkO, SkO', SkI4, and SV-bas) is used. Light and heavy, spherical and deformed nuclei ({sup 48}Ca, {sup 158}Gd, {sup 208}Pb, and {sup 238}U) are considered. The calculations show that spin densities play a crucial role in forming the collective shift in the spectrum. The interplay of the collective shift and spin-orbit splitting determines the quality of the description. None of the considered Skyrme parametrizations is able to describe simultaneously the M1 strength distribution in closed-shell and open-shell nuclei. It is found that the problem lies in the relative positions of proton and neutron spin-orbit splitting. This calls for a better modeling of the tensor and isovector spin-orbit interaction.

Vesely, P.; Kvasil, J. [Institute of Particle and Nuclear Physics, Charles University, CZ-18000, Praha 8 (Czech Republic); Nesterenko, V. O. [Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Moscow region, RU-141980 (Russian Federation); Kleinig, W. [Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna, Moscow region, RU-141980 (Russian Federation); Technische Universitaet Dresden, Inst. fuer Analysis, D-0106 Dresden (Germany); Reinhard, P.-G. [Institut fuer Theoretische Physik II, Universitaet Erlangen, D-91058 Erlangen (Germany); Ponomarev, V. Yu. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)

2009-09-15T23:59:59.000Z

431

Spin angular momentum transfer in current-perpendicular nanomagnetic junctions  

Science Conference Proceedings (OSTI)

Spin angular momentum transfer, or spin-transfer, describes the transfer of spin angular momentum between a spin-polarized current and a ferromagnetic conductor. The angular momentum transfer exerts a torque (spin-current induced torque, or spin-torque) ...

J. Z. Sun

2006-01-01T23:59:59.000Z

432

Model for Entangled States with Spin-Spin Interaction  

E-Print Network (OSTI)

A system consisting of two neutral spin 1/2 particles is analyzed for two magnetic field perturbations: 1) an inhomogeneous magnetic field over all space, and 2) external fields over a half space containing only one of the particles. The field is chosen to point from one particle to the other, which results in essentially a one-dimensional problem. A number of interesting features are revealed for the first case: the singlet, which has zero potential energy in the unperturbed case, remains unstable in the perturbing field. The spin zero component of the triplet evolves into a bound state with a double well potential, with the possibility of tunneling. Superposition states can be constructed which oscillate between entangled and unentangled states. For the second case, we show that changes in the magnetic field around one particle affect measurements of the spin of the entangled particle not in the magnetic field nonlocally. By using protective measurements, we show it is possible in principle to establish a nonlocal interaction using the two particles, provided the dipole-dipole potential energy does not vanish and is comparable to the potential energy of the particle in the external field.

Yakir Aharonov; Jeeva Anandan; G. Jordan Maclay; Jun Suzuki

2004-07-28T23:59:59.000Z

433

Neutron electric polarizability  

E-Print Network (OSTI)

We use the background field method to extract the "connected" piece of the neutron electric polarizability. We present results for quenched simulations using both clover and Wilson fermions and discuss our experience in extracting the mass shifts and the challenges we encountered when we lowered the quark mass. For the neutron we find that as the pion mass is lowered below $500\\MeV$, the polarizability starts rising in agreement with predictions from chiral perturbation theory. For our lowest pion mass, $m_\\pi=320\\MeV$, we find that $\\alpha_n = 3.8(1.3)\\times 10^{-4}\\fm^3$, which is still only one third of the experimental value. We also present results for the neutral pion; we find that its polarizability turns negative for pion masses smaller than $500\\MeV$ which is puzzling.

Andrei Alexandru; Frank X. Lee

2009-11-13T23:59:59.000Z

434

Impact of Triaxiality on the Emission and Absorption of Neutrons and Gamma Rays in Heavy Nuclei  

E-Print Network (OSTI)

For many spin-0 target nuclei neutron capture measurements yield information on level densities at the neutron separation energy. Also the average photon width has been determined from capture data as well as Maxwellian average cross sections for the energy range of unresolved resonances. Thus it is challenging to use this data set for a test of phenomenological prescriptions for the prediction of radiative processes. An important ingredient for respective calculations is the photon strength function for which a parameterization was proposed using a fit to giant dipole resonance shapes on the basis of theoretically determined ground state deformations including triaxiality. Deviations from spherical and axial symmetry also influence level densities and it is suggested to use a combined parameterization for both, level density and photon strength. The formulae presented give a good description of the data for low spin capture into 124 nuclei with 72

Grossea, Eckart; Massarczyk, Ralph

2013-01-01T23:59:59.000Z

435

Research Highlights | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

ARCS maps collaborative magnetic spin behavior in iron telluride Published Work: "Unconventional Temperature Enhanced Magnetism in Fe1:1Te" (2011) Contact: Igor Zaliznyak...

436

THERMAL NEUTRONIC REACTOR  

DOE Patents (OSTI)

A novel thermal reactor was designed in which a first reflector formed from a high atomic weight, nonmoderating material is disposed immediately adjacent to the reactor core. A second reflector composed of a moderating material is disposed outwardly of the first reflector. The advantage of this novel reflector arrangement is that the first reflector provides a high slow neutron flux in the second reflector, where irradiation experiments may be conducted with a small effect on reactor reactivity.

Spinrad, B.I.

1960-01-12T23:59:59.000Z

437

A single-spin precessing gravitational wave in closed form  

E-Print Network (OSTI)

In coming years, gravitational wave detectors should find black hole-neutron star binaries, potentially coincident with astronomical phenomena like short GRBs. These binaries are expected to precess. Gravitational wave science requires a tractable model for precessing binaries, to disentangle precession physics from other phenomena like modified strong field gravity, tidal deformability, or Hubble flow; and to measure compact object masses, spins, and alignments. Moreover, current searches for gravitational waves from compact binaries use templates where the binary does not precess and are ill-suited for detection of generic precessing sources. In this paper we provide a closed-form representation of the single-spin precessing waveform in the frequency domain by reorganizing the signal as a sum over harmonics, each of which resembles a nonprecessing waveform. This form enables simple analytic calculations (e.g., a Fisher matrix) with easily-interpreted results. We have verified that for generic BH-NS binaries, our model agress with the time-domain waveform to 2\\%. Straightforward extensions of the derivations outlined here [and provided in full online] allow higher accuracy and error estimates.

A. Lundgren; R. O'Shaughnessy

2013-04-11T23:59:59.000Z

438

High-spin states in {sup 96,97}Nb  

Science Conference Proceedings (OSTI)

The high-spin level structures of the {sup 96,97}Nb isotopes have been studied. The isotopes were produced in the fission of the compound systems formed in two heavy-ion-induced reactions, {sup 24}Mg (134.5 MeV) + {sup 173}Yb and {sup 23}Na (129 MeV) + {sup 176}Yb. Gamma-ray spectroscopy was accomplished with the Gammasphere array. High-spin states are observed for the first time in both isotopes with excitation energies up to 5.2 and 6.6 MeV in {sup 96,97}Nb, respectively. The coupling of the odd proton occupying the g{sub 9/2} orbital to the yrast states in the subshell closure nucleus of {sup 96}Zr can account for the first excited states of {sup 97}Nb. A comparison with the first excited states in {sup 95}Zr is also attempted. The addition of a neutron hole in {sup 96}Nb results in a much more fragmented level scheme.

Fotiades, N.; Cizewski, J. A.; Kruecken, R.; Clark, R. M.; Fallon, P.; Lee, I. Y.; Macchiavelli, A. O.; Becker, J. A.; Younes, W. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903 (United States); Physik Department E12, Technische Universitaet Muenchen, D-85748 Garching (Germany); Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2010-10-15T23:59:59.000Z

439

Neutron dosimetry at SLAC: Neutron sources and instrumentation  

Science Conference Proceedings (OSTI)

This report summarizes in detail the dosimetric characteristics of the five radioisotopic type neutron sources ({sup 238}PuBe, {sup 252}Cf, {sup 238}PuB, {sup 238}PuF{sub 4}, and {sup 238}PuLi) and the neutron instrumentation (moderated BF{sub 3} detector, Anderson-Braun (AB) detector, AB remmeter, Victoreen 488 Neutron Survey Meter, Beam Shut-Off Ionization Chamber, {sup 12}C plastic scintillator detector, moderated indium foil detector, and moderated and bare TLDs) that are commonly used for neutron dosimetry at the Stanford Linear Accelerator Center (SLAC). 36 refs,. 19 figs.

Liu, J.C.; Jenkins, T.M.; McCall, R.C.; Ipe, N.E.

1991-10-01T23:59:59.000Z

440

Neutron Detection Using an Embedded Sol-Gel Neutron Absorber  

on sol-gel chemistry, uses metallic oxides embedded in a glass film that fission when bombarded with neutrons, producing a signature event in the ...

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Review of Non-Neutron and Neutron Nuclear Data, 2004  

Science Conference Proceedings (OSTI)

Review articles are in preparation for the 2004 edition of the CRC Handbook of Chemistry and Physics dealing with the evaluation of both non-neutron and neutron nuclear data. Data on the discovery of element 110, Darmstadtium, and element 111 have been officially accepted, while data on element 118 have been withdrawn. Data to be presented include revised values for very short-lived nuclides, long-lived nuclides, and beta-beta decay measurements. There has been a reassessment of the spontaneous fission (sf) half-lives, which distinguishes between sf decay half-lives and cluster decay half-lives, and with cluster-fission decay. New measurements of isotopic abundance values for many elements will be discussed with an emphasis on the minor isotopes of interest for use in neutron activation analysis measurements. Neutron resonance integrals will be discussed emphasizing the differences between the calculated values obtained from the analytical integration over neutron resonances and the measured values in a neutron reactor-spectrum, which does not quite conform to the assumed 1/E neutron energy spectrum. The method used to determine the neutron resonance integral from measurement, using neutron activation analysis, will be discussed.

Holden, Norman E. [National Nuclear Data Center, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States)

2005-05-24T23:59:59.000Z

442

REVIEW OF NON-NEUTRON AND NEUTRON NUCLEAR DATA, 2004.  

Science Conference Proceedings (OSTI)

Review articles are in preparation for the 2004 edition of the CRC Handbook of Chemistry and Physics dealing with the evaluation of both non-neutron and neutron nuclear data. Data on the discovery of element 110, Darmstadtium, and element 111 have been officially accepted, while data on element 11 8 have been withdrawn. Data to be presented include revised values for very short-lived nuclides, long-lived nuclides and beta-beta decay measurements. There has been a reassessment of the spontaneous fission (sf) half-lives, which distinguishes between sf decay half-lives and cluster decay half-lives and with cluster-fission decay. New measurements of isotopic abundance values for many elements will be discussed with an emphasis on the minor isotopes of interest for use in neutron activation analysis measurements. Neutron resonance integrals will be discussed emphasizing the differences between the calculated values obtained from the analytical integration over neutron resonances and the measured values in a neutron reactor-spectrum, which does not quite conform to the assumed 1/E neutron energy spectrum. The method used to determine the neutron resonance integral from measurement, using neutron activation analysis, will be discussed.

HOLDEN, N.E.

2004-09-26T23:59:59.000Z

443

American Conference on Neutron Scattering 2010 - ORNL Neutron...  

NLE Websites -- All DOE Office Websites (Extended Search)

Update on Sample Environment Plenary Session: Thom Mason: Neutron Scattering and Energy ACNS website with Program Back to Top an error occurred while processing this directive...

444

Precision Measurement Of The Neutron's Beta Asymmetry Using Ultra-Cold Neutrons  

Science Conference Proceedings (OSTI)

A measurement of A{beta}, the correlation between the electron momentum and neutron (n) spin (the beta asymmetry) in n beta-decay, together with the n lifetime, provides a method for extracting fundamental parameters for the charged-current weak interaction of the nucleon. In particular when combined with decay measurements, one can extract the Vud element of the CKM matrix, a critical element in CKM unitarity tests. By using a new SD2 super-thermal source at LANSCE, large fluxes of UCN (ultra-cold neutrons) are expected for the UCNA project. These UCN will be 100% polarized using a 7 T magnetic field, and directed into the {beta} spectrometer. This approach, together with an expected large reduction in backgrounds, will result in an order of magnitude reduction in the critical systematic corrections associated with current n {beta}-asymmetry measurements. This paper will give an overview of the UCNA A{beta} measurement as well as an update on the status of the experiment.

Makela, M. [Los Alamos National Lab., P.O. Box 1663, Los Alamos, NM 87545 (United States); Back, H. O. [North Carolina State University Raleigh, NC 27695 (United States); Melconian, D. [University of Washington, Department of Physics, Box 351560 Seattle, WA 98195 (United States); Plaster, B. [California Institute of Technology, Kellogg Radiation Lab, Pasadena, CA 91125 (United States)

2006-07-11T23:59:59.000Z

445

Spin injection into semiconductors : the role of Fe/Al[sub x]Ga[sub 1-x]As interface  

SciTech Connect

The influence of the growth and post-growth annealing temperatures of Fe/Al{sub x}Ga{sub 1-x}As-based spin light-emitting diodes (LEDs) on the spin injection efficiency is discussed. The extent of interfacial reactions during molecular beam epitaxial growth of Fe on GaAs was determined from in-situ x-ray photoelectron spectroscopy studies. The Fe/GaAs interface results in {<=} 3 monolayers of reaction for Fe grown at -15 C. Intermediate growth temperatures (95 C) lead to {approx}5 monolayers of interfacial reactions, and high growth temperatures of 175 C lead to a {approx}9 monolayer thick reacted layer. Polarized neutron reflectivity was used to determine the interfacial magnetic properties of epitaxial Fe{sub 0.5}Co{sub 0.5}/GaAs heterostructures grown under identical conditions. No interfacial magnetic dead layer is detected at the interface for Fe{sub 0.5}Co{sub 0.5} films grown at -15 C, an {approx}6 {angstrom} thick nonmagnetic layer formed at the interface for 95 C growth and an {approx}5 {angstrom} thick magnetic interfacial reacted layer formed for growth at 175 C. Spin injection from Fe contacts into spin LEDs decreases sharply when reactions result in a nonmagnetic interfacial layer. Significant spin injection signals are obtained from Fe contacts grown between -5 C and 175 C, although the higher Fe growth temperatures resulted in a change in the sign of the spin polarization. Post-growth annealing of the spin LEDs is found to increase spin injection efficiency for low Fe growth temperatures and to a sign reversal of the spin polarization for high growth temperature (175 C). An effective Schottky barrier height increase indicates that post growth annealing modifies the Fe/Al{sub x}Ga{sub 1-x}As interface.

Fitzsimmons, M. R. (Michael R.); Park, S. (Sungkyun)

2004-01-01T23:59:59.000Z

446

Demand Response Spinning Reserve Demonstration  

Science Conference Proceedings (OSTI)

The Demand Response Spinning Reserve project is a pioneeringdemonstration of how existing utility load-management assets can providean important electricity system reliability resource known as spinningreserve. Using aggregated demand-side resources to provide spinningreserve will give grid operators at the California Independent SystemOperator (CAISO) and Southern California Edison (SCE) a powerful, newtool to improve system reliability, prevent rolling blackouts, and lowersystem operating costs.

Eto, Joseph H.; Nelson-Hoffman, Janine; Torres, Carlos; Hirth,Scott; Yinger, Bob; Kueck, John; Kirby, Brendan; Bernier, Clark; Wright,Roger; Barat, A.; Watson, David S.

2007-05-01T23:59:59.000Z

447

Neutron Imaging by Boric Acid  

E-Print Network (OSTI)

In this paper a new type of passive neutron detector based on the already existing one, CR39, is described. Its operation was verified by three different neutron sources: an Americium-Beryllium (Am241-Be) source; a TRIGA type nuclear reactor; and a fast neutron reactor called TAPIRO. The obtained results, reported here, positively confirm its operation and the accountability of the new developed detecting technique.

Fabio Cardone; Giovanni Cherubini; Walter Perconti; Andrea Petrucci; Alberto Rosada

2013-02-22T23:59:59.000Z

448

Research Highlights | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

reveals semiconducting phase and contributes to new understanding of iron-based superconductors Contact: Huibo Cao Neutron scattering measures samples too hot to hold Contact:...

449

Imaging Highlights | Neutron Science | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

(3-D) neutron images have been taken of rare archaeological artifacts. Bronze and brass artifacts excavated at the ancient city of Petra, in present day Jordan, were recently...

450

Archeological Imaging | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

(3-D) neutron images have been taken of rare archaeological artifacts. Bronze and brass artifacts excavated at the ancient city of Petra, in present day Jordan, were recently...

451

NIST Center for Neutron Research  

Science Conference Proceedings (OSTI)

... supported by the National Science Foundation ... Spectroscopy The energy scale of neutrons ( meV ... posted some proposal statistics summarizing the ...

452

Neutron and Nano User Meeting  

NLE Websites -- All DOE Office Websites (Extended Search)

Science @ Neutron and Nano Facilities User Workshops Integrated Agendas Venue Travel Information Contacts and Sponsors Registration Registration is now closed Contact Al Ekkebus,...

453

Awards 2012 | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Neutron Source, and multiscale simulations using the computational resources at the Oak Ridge Leadership Computing Facility. This year awards were given to 68 recipients from...

454

Research Highlights | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Research Highlights For all the latest highlights on research at HFIR and SNS, please see the links at left. Featured Research Neutron diffraction reveals semiconducting phase and...

455

Neutron Characterization for Additive Manufacturing  

NLE Websites -- All DOE Office Websites (Extended Search)

such as the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR) shown in Fig. 1 to solve challenging problems in additive manu- facturing (AM)....

456

News & Events | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

or your library directly. December Our Views: Bipartisan state, federal support for SNS necessary Oak Ridger, 1220 The success, thus far, of the Spallation Neutron Source...

457

Nanotechnology Highlights | Neutron Scoence | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Nanotechnology SHARE Nanotechnology Highlights 1-4 of 4 Results Neutron Imaging Explored as Complementary Technique for Improving Cancer Detection August 05, 2013 - Today's range...

458

Research Highlights | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Polytechnic Institute used small-angle neutron scattering (SANS) at the High-Flux Isotope Reactor at Oak Ridge National Laboratory to identify these early stage aggregates in...

459

BASIS Highlights | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

in water and other glass-forming liquids, covering six research collaborations at ORNL Neutron scattering provides window into surface interactions High-performance...

460

Research Highlights | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

of electrons through the semiconductor. Researchers from the University of Alabama and ORNL used polarized neutrons at the MR to investigate the electronic, magnetic, and...

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Research Highlights | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

techniques with neutron scattering at the General-Purpose SANS instrument at the ORNL High Flux Isotope Reactor. The cell mimics were vesicles (hollow spheres) made of...

462

Portable neutron spectrometer and dosimeter  

DOE Patents (OSTI)

The disclosure relates to a battery operated neutron spectrometer/dosimeter utilizing a microprocessor, a built-in tissue equivalent LET neutron detector, and a 128-channel pulse height analyzer with integral liquid crystal display. The apparatus calculates doses and dose rates from neutrons incident on the detector and displays a spectrum of rad or rem as a function of keV per micron of equivalent tissue and also calculates and displays accumulated dose in millirads and millirem as well as neutron dose rates in millirads per hour and millirem per hour.

Waechter, David A. (Los Alamos, NM); Erkkila, Bruce H. (Los Alamos, NM); Vasilik, Dennis G. (Los Alamos, NM)

1985-01-01T23:59:59.000Z

463

Neutron Science Research Areas | ORNL  

NLE Websites -- All DOE Office Websites (Extended Search)

Biology and Soft Matter Chemical and Engineering Materials Quantum Condensed Matter Neutron Data Analysis and Visualization Research Highlights Facilities and Capabilities...

464

The Cold Neutron Source core  

Science Conference Proceedings (OSTI)

... walls are necessary for the containment of the ... a recombination of radiolysis products is induced in ... Neutrons are produced by fission with energies ...

2009-11-29T23:59:59.000Z

465

Centrifugal quantum states of neutrons  

E-Print Network (OSTI)

We propose a method for observation of the quasi-stationary states of neutrons, localized near the curved mirror surface. The bounding effective well is formed by the centrifugal potential and the mirror Fermi-potential. This phenomenon is an example of an exactly solvable "quantum bouncer" problem that could be studied experimentally. It could provide a promising tool for studying fundamental neutron-matter interactions, as well as quantum neutron optics and surface physics effects. We develop formalism, which describes quantitatively the neutron motion near the mirror surface. The effects of mirror roughness are taken into account.

V. V. Nesvizhevsky; A. K. Petukhov; K. V. Protasov; A. Yu. Voronin

2008-06-24T23:59:59.000Z

466

NEUTRON IMAGING, RADIOGRAPHY AND TOMOGRAPHY.  

SciTech Connect

Neutrons are an invaluable probe in a wide range of scientific, medical and commercial endeavors. Many of these applications require the recording of an image of the neutron signal, either in one-dimension or in two-dimensions. We summarize the reactions of neutrons with the most important elements that are used for their detection. A description is then given of the major techniques used in neutron imaging, with emphasis on the detection media and position readout principle. Important characteristics such as position resolution, linearity, counting rate capability and sensitivity to gamma-background are discussed. Finally, the application of a subset of these instruments in radiology and tomography is described.

SMITH,G.C.

2002-03-01T23:59:59.000Z

467

Teacher Programs | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

Diffractometer, explains neutron diffractometry to teachers participating in the STARs program. Ashfia Huq (front), instrument scientist for the SNS Powder Diffractometer, explains...

468

Cooperative Ordering of Gapped and Gapless Spin Networks in Cu2Fe2Ge4O13  

SciTech Connect

The unusual magnetic properties of a novel low-dimensional quantum ferrimagnet Cu{sub 2}Fe{sub 2}Ge{sub 4}O{sub 13} are studied using bulk methods, neutron diffraction, and inelastic neutron scattering. It is shown that this material can be described in terms of two low-dimensional quantum spin subsystems, one gapped and the other gapless, characterized by two distinct energy scales. Long-range magnetic ordering observed at low temperatures is a cooperative phenomenon caused by weak coupling of these two spin networks.

Masuda, Takatsugu [ORNL; Zheludev, Andrey I [ORNL; Grenier, B. [CEA, Grenoble, France; Imai, S. [University of Tokyo, Tokyo, Japan; Uchinokura, K. [RIKEN, Japan; Ressouche, E. [CEA, Grenoble, France; Park, S. [National Institute of Standards and Technology (NIST)

2004-01-01T23:59:59.000Z

469

Threshold Resonant Structure of the 232Th Neutron-Induced Fission Cross Section  

E-Print Network (OSTI)

The structures observed in the sub-threshold neutron-induced fission of ^{232}Th were investigated employing a recent developed model. Theoretical single-particle excitations of a phenomenological two-humped barrier are determined by solving a system of coupled differential equations for the motion along the optimal fission path. A rather good agreement with experimental data was obtained using a small number of independent parameters. It is predicted that the structure at 1.4 and 1.6 MeV is mainly dominated by spin 3/2 partial cross-section with small admixture of spin 1/2, while the structure at 1.7 MeV is given by a large partial cross section of spin 5/2.

M. Mirea; L. Tassan-Got; C. Stephan; C. O. Bacri; R. C. Bobulescu

2007-08-08T23:59:59.000Z

470

When can gravitational-wave observations distinguish between black holes and neutron stars?  

E-Print Network (OSTI)

Gravitational-wave observations of compact binaries have the potential to uncover the distribution of masses and angular momenta of black holes and neutron stars in the universe. The binary components' physical parameters can be inferred from their effect on the phasing of the gravitational-wave signal, but a partial degeneracy between the components' mass ratio and their angular momenta limits our ability to measure the individual component masses. At the typical signal amplitudes expected by the Advanced Laser Interferometer Gravitational-wave Observatory (signal-to-noise ratios between 10 and 20), we show that it will in many cases be difficult to distinguish whether the components are neutron stars or black holes. We identify when the masses of the binary components could be unambiguously measured outside the range of current observations: a system with a chirp mass $\\mathcal{M} \\le 0.871 $ M$_\\odot$ would unambiguously contain the smallest-mass neutron star observed, and a system with $\\mathcal{M} \\ge 2.786 \\Msun$ must contain a black hole. However, additional information would be needed to distinguish between a binary containing two 1.35 M$_\\odot$ neutron stars and an exotic neutron-star--black-hole binary. We also identify those configurations that could be unambiguously identified as black-hole binaries, and show how the observation of an electromagnetic counterpart to a neutron-star--black-hole binary could be used to constrain the black-hole spin.

Mark Hannam; Duncan A. Brown; Stephen Fairhurst; Chris L. Fryer; Ian W. Harry

2013-01-23T23:59:59.000Z

471

Spallation Neutron Source The Spallation Neutron Source (SNS)  

NLE Websites -- All DOE Office Websites (Extended Search)

F/gim F/gim Spallation Neutron Source The Spallation Neutron Source (SNS) gives researchers more detailed informa- tion on the structure and dynamics of physical and biological materials than ever before possible. This accelerator- based facility provides the most intense pulsed neutron beams in the world. Scien- tists are able to count scattered neutrons, measure their energies and the angles at which they scatter, and map their final positions. SNS enables measurements of greater sensitivity, higher speed, higher resolution, and in more complex sample environments than have been possible at existing neutron facilities. Future Growth SNS was designed from the outset to accommodate a second target station, effectively doubling the capacity of the

472

Neutron beam imaging at neutron spectrometers at Dhruva  

SciTech Connect

A low efficiency, 2-Dimensional Position Sensitive Neutron Detector based on delay line position encoding is developed. It is designed to handle beam flux of 10{sup 6}-10{sup 7} n/cm{sup 2}/s and for monitoring intensity profiles of neutron beams. The present detector can be mounted in transmission mode, as the hardware allows maximum neutron transmission in sensitive region. Position resolution of 1.2 mm in X and Y directions, is obtained. Online monitoring of beam images and intensity profile of various neutron scattering spectrometers at Dhruva are presented. It shows better dynamic range of intensity over commercial neutron camera and is also time effective over the traditionally used photographic method.

Desai, Shraddha S.; Rao, Mala N. [Solid State Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

2012-06-05T23:59:59.000Z

473

CIM - compact intensity modulation.  

SciTech Connect

Compact intensity modulation (CIM), a new method to modulate the intensity of a neutron beam is demonstrated. CIM allows the production of arbitrary signals where the focus point can be chosen and changed without any constraints. A novel feature in this technique compared to spin echo techniques is that the neutron polarization is kept parallel or anti-parallel to the static fields during the passage through the magnetic fields and the beating pattern at the detector is produced by an amplitude modulation (AM) of the adiabatic RF-spin flippers rather than Larmor precession like in neutron spin echo (NSE) instruments; thus, the achievable contrast is very high and the instrument resolution can be changed very quickly. This gives the fascinating possibility at pulsed neutron sources to sweep the modulation frequency of the flippers in order to increase dynamic resolution range during the same neutron pulse.

Bleuel, M.; Lang, E.; Gahler, G.; Lal, J.; Intense Pulsed Neutron Source; Inst. Lau Langevin

2008-07-21T23:59:59.000Z

474

Definition: Spinning Reserve | Open Energy Information  

Open Energy Info (EERE)

Spinning Reserve Spinning Reserve Jump to: navigation, search Dictionary.png Spinning Reserve Unloaded generation that is synchronized and ready to serve additional demand.[1] View on Wikipedia Wikipedia Definition In electricity networks, the operating reserve is the generating capacity available to the system operator within a short interval of time to meet demand in case a generator goes down or there is another disruption to the supply. Most power systems are designed so that, under normal conditions, the operating reserve is always at least the capacity of the largest generator plus a fraction of the peak load. The operating reserve is made up of the spinning reserve as well as the non-spinning or supplemental reserve: The spinning reserve is the extra generating capacity

475

Cavity cooling of an ensemble spin system  

E-Print Network (OSTI)

We describe how sideband cooling techniques, prevalent in quantum optics, may be applied to large spin ensembles in magnetic resonance. Using the Tavis-Cummings model in the presence of a Rabi drive, we solve a Markovian master equation describing the joint spin-cavity dynamics to derive cooling rates as a function of ensemble size. Our calculations indicate that a spin ensemble containing roughly $10^{11}$ electron spins may be polarized to a non-thermal equilibrium state in a time many orders of magnitude shorter than the typical thermal relaxation time. The described techniques permit the efficient removal of entropy for spin-based quantum information processors and fast polarization of spin samples. The proposed application of a standard technique in quantum optics to magnetic resonance also serves to reinforce the connection between the two fields, which has only recently begun to be explored in detail due to the development of hybrid designs for manufacturing noise-resilient quantum devices.

Christopher J. Wood; Troy W. Borneman; David G. Cory

2013-05-05T23:59:59.000Z

476

Probing spin flip scattering in ballistic nanosystems  

Science Conference Proceedings (OSTI)

Because spin-flip scattering length is longer than the electron mean-free-path in a metal, past studies of spin-flip scattering are limited to the diffusive regime. Spin accumulation in the nanometer sized spacer layer of a magnetic double barrier tunnel junction allows the study of spin flip scattering near ballistic limit. We extract the spin-flip conductance $G_s$ of the spacer layer from magnetoresistance measurements. A linear temperature dependence of $G_s$ is found. The bias voltage dependence shows a quantum well resonance which explains the sharp reduction of the magnetoresistance. At 4.2K $G_s$ yields the mean-free-path (70nm) and the spin-flip length ($1.0$-$2.6\\mu$m).

Zeng, Z. M. [Institute of Physics, Chinese Academy of Science; Feng, J. F. [Institute of Physics, Chinese Academy of Science; Wang, Y. [Institute of Physics, Chinese Academy of Science; Han, Prof. X. F. [Institute of Physics, Chinese Academy of Science; Zhan, W. S. [Institute of Physics, Chinese Academy of Science; Zhang, Xiaoguang [ORNL; Zhang, Z. [Institute of Physics, Chinese Academy of Science

2006-01-01T23:59:59.000Z

477

Neutron Imaging of Hydrogen in Steels  

Science Conference Proceedings (OSTI)

Symposium, Applied Neutron Scattering in Engineering and Materials Science Research. Presentation Title, Neutron Imaging of Hydrogen in Steels. Author(s) ...

478

HFIR Technical Parameters | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

a thorough understanding of how elements react to neutron bombardment. Facilities at HFIR Two Pneumatic Tubes: PT-1: Thermal Neutron Flux: 4 1014 n cm-2 s-1...

479

Data Management Practices | ORNL Neutron Sciences  

NLE Websites -- All DOE Office Websites (Extended Search)

to data generated from neutron scattering experiments at the High Flux Isotope Reactor (HFIR) and the Spallation Neutron Source (SNS). Any changes to these guidelines will be...

480

What Can You Do With Neutrons?  

NLE Websites -- All DOE Office Websites (Extended Search)

the globe, including the Spallation Neutron Source (SNS) and High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Today the number of active neutron users in...

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
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to obtain the most current and comprehensive results.


481

Neutron Scatter Camera for Radiaton Detection - Energy ...  

Patent 7,741,613: Neutron scatter camera An instrument that will directly image the fast fission neutrons from a special nuclear material source has ...

482

Electrospun Polymer Nanofiber Composite as Thermal Neutron ...  

Science Conference Proceedings (OSTI)

Lithium-6 isotope has a significant thermal neutron cross-section and produces high energy charged particles on thermal neutron absorption. In this research ...

483

Competitive Asset: NIST Center for Neutron Research  

Science Conference Proceedings (OSTI)

... university scientists are finding neutrons essential to accomplishing ... is the most heavily used facility of its ... of the other US neutron research facilities. ...

2011-04-11T23:59:59.000Z

484

NEUTRONIC REACTOR CONSTRUCTION  

DOE Patents (OSTI)

A cover device is described for the fuel element receiving tube of a neutronic reactor of the heterogeneous, water cooled type wherein said tubes are arranged in a moderator with their longitudinal axes vertical. The cover is provided with means to support a rod-type fuel element from the bottom thereof and means to lock the cover in place, the latter being adapted for remote operation. This cover device is easily removable and seals the opening in the upper end of the fuel tube against leakage of coolant.

Vernon, H.C.; Goett, J.J.

1958-09-01T23:59:59.000Z

485

What Do s- and p-Wave Neutron Average Radiative Widths Reveal  

Science Conference Proceedings (OSTI)

A first observation of two resonance-like structures at mass numbers 92 and 112 in the average capture widths of the p-wave neutron resonances relative to the s-wave component is interpreted in terms of a spin-orbit splitting of the 3p single-particle state into P{sub 3/2} and P{sub 1/2} components at the neutron separation energy. A third structure at about A = 124, which is not correlated with the 3p-wave neutron strength function, is possibly due to the Pygmy Dipole Resonance. Five significant results emerge from this investigation: (i) The strength of the spin-orbit potential of the optical-model is determined as 5.7 {+-} 0.5 MeV, (ii) Non-statistical effects dominate the p-wave neutron-capture in the mass region A = 85 - 130, (iii) The background magnitude of the p-wave average capture-width relative to that of the s-wave is determined as 0.50 {+-} 0.05, which is accounted for quantitatively in tenns of the generalized Fermi liquid model of Mughabghab and Dunford, (iv) The p-wave resonances arc partially decoupled from the giant-dipole resonance (GDR), and (v) Gamma-ray transitions, enhanced over the predictions of the GDR, are observed in the {sup 90}Zr - {sup 98}Mo and Sn-Ba regions.

Mughabghab, S.F.

2010-04-30T23:59:59.000Z

486

Higher Spin Black Holes from CFT  

E-Print Network (OSTI)

Higher spin gravity in three dimensions has explicit black holes solutions, carrying higher spin charge. We compute the free energy of a charged black hole from the holographic dual, a 2d CFT with extended conformal symmetry, and find exact agreement with the bulk thermodynamics. In the CFT, higher spin corrections to the free energy can be calculated at high temperature from correlation functions of W-algebra currents.

Gaberdiel, Matthias R; Jin, Kewang

2012-01-01T23:59:59.000Z

487

Higher Spin Black Holes from CFT  

E-Print Network (OSTI)

Higher spin gravity in three dimensions has explicit black holes solutions, carrying higher spin charge. We compute the free energy of a charged black hole from the holographic dual, a 2d CFT with extended conformal symmetry, and find exact agreement with the bulk thermodynamics. In the CFT, higher spin corrections to the free energy can be calculated at high temperature from correlation functions of W-algebra currents.

Matthias R. Gaberdiel; Thomas Hartman; Kewang Jin

2012-02-29T23:59:59.000Z

488

Adaptive nonparametric regression on spin fiber bundles  

Science Conference Proceedings (OSTI)

The construction of adaptive nonparametric procedures by means of wavelet thresholding techniques is now a classical topic in modern mathematical statistics. In this paper, we extend this framework to the analysis of nonparametric regression on sections ... Keywords: 42B35, 42C10, 42C40, 46E35, 62G08, 62G20, Adaptive nonparametric regression, Mixed spin needlets, Spin Besov spaces, Spin fiber bundles, Thresholding

Claudio Durastanti; Daryl Geller; Domenico Marinucci

2012-02-01T23:59:59.000Z

489

Spin Chaos Manifestation in a Driven Quantum Billiard with Spin-Orbit Coupling  

E-Print Network (OSTI)

The coupling of orbital and spin degrees of freedom is the source of many interesting phenomena. Here, we study the electron dynamics in a quantum billiard --a mesoscopic rectangular quantum dot-- with spin-orbit coupling driven by a periodic electric field. We find that both the spatial and temporal profiles of the observables demonstrate the transition to chaotic dynamics with qualitative modifications of the power spectra and patterns of probability and spin density. The time dependence of the wavefunctions and spin density distributions indicates spin-charge separation {seen in the decay of the spin-charge density correlators}. This new spin chaos effect can be experimentally verified leading to a better understanding of the interplay between spin and spatial degrees of freedom, relevant to fundamental and applied quantum physics.

D. V. Khomitsky; A. I. Malyshev; E. Ya. Sherman; M. Di Ventra

2013-08-10T23:59:59.000Z

490

Spin current switching and spin-filtering effects in Mn-doped boron nitride nanoribbons  

Science Conference Proceedings (OSTI)

The spin transport properties are investigated by means of the first principle approach for boron nitride nanoribbons with one or two substitutional Mn impurities, connected to graphene electrodes. The spin current polarization is evaluated using the ...

G. A. Nemnes

2012-01-01T23:59:59.000Z