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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

Concepts in spin echo small-angle neutron scattering  

Science Journals Connector (OSTI)

Two-dimensional spin echo small-angle neutron scattering experiments are proposed for the direct measurement of the vector-length distribution function. Interpretation of the correlation function from one-dimensional experiments is also presented.

Zhao, J.

2001-09-25T23:59:59.000Z

2

Spin-echo small-angle neutron scattering in neutron reflectometry  

Science Journals Connector (OSTI)

A new method to perform neutron reflectometry measurements is discussed, based on Larmor precession of polarized neutrons in the spin-echo mode.

Rekveldt, M.T.

2003-11-15T23:59:59.000Z

3

Neutron resonance spin echo, bootstrap method for increasing the effective magnetic field  

E-Print Network [OSTI]

1195 Neutron resonance spin echo, bootstrap method for increasing the effective magnetic field R donné en spectrométrie d'echos de spins de neutrons. Les limites théoriques et techniques à l field intensity in Neutron Resonance Spin Echo (NRSE) spectrometry. The limits, theoretical as well

Paris-Sud XI, Université de

4

Contrast variation in spin-echo small angle neutron scattering  

Science Journals Connector (OSTI)

The use of contrast variation in spin-echo small angle neutron scattering (SESANS) experiments is discussed for the case of colloidal structural investigation. On the basis of calculations for several model systems, we find that the contrast variation SESANS technique, in terms of the measured SESANS correlation function G(z), is not sensitive to the structural characteristics of colloidal suspensions consisting of particles with uniform scattering length density profiles. However, its ability to resolve structural heterogeneity, at both intra-colloidal and inter-colloidal length scales, is clearly demonstrated. The prospect of using this new technique to investigate structural information that is difficult to probe in other ways is also explored.

Xin Li; Bin Wu; Yun Liu; Roger Pynn; Chwen-Yang Shew; Gregory S Smith; Kenneth W Herwig; J Lee Robertson; Wei-Ren Chen; Li Liu

2012-01-01T23:59:59.000Z

5

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

6

A novel neutron spin echo technique for measuring phonon linewidths using magnetic Wollaston prisms  

Science Journals Connector (OSTI)

A neutron spin echo spectrometer based on neutron magnetic Wollaston prisms is introduced to measure the linewidth of dispersive phonon excitations over the entire Brillouin zone with ?eV resolution. By tuning the instrument electromagnetically, the linewidths of phonon excitations with high energy and large group velocity can be measured.

Li, F.

2014-10-17T23:59:59.000Z

7

Neutron phase echo  

Science Journals Connector (OSTI)

The coherent overlap of the waves traversing the two legs of a perfect-crystal neutron interferometer is altered by a material with a neutron-nuclear optical potential. The fringe visibility is limited by the longitudinal coherence length. The loss of interference contrast caused by a slab of material of positive optical potential can be restored by placing another slab of material with a negative optical potential in the same leg of the interferometer. This paper describes the observation and detailed characterization of this quantum-mechanical phenomenon, which we call the phase-echo effect.

R. Clothier; H. Kaiser; S. A. Werner; H. Rauch; H. Wlwitsch

1991-11-01T23:59:59.000Z

8

HIGH RESOLUTION NMR IN INHOMOGENEOUS MAGNETIC FIELDS: APPLICATION OF TOTAL SPIN COHERENCE TRANSFER ECHOES  

E-Print Network [OSTI]

APPLICATION OF TOTAL SPIN COHERENCE TRANSFER ECHOES D.P.by total spin coherence transfer echo spectroscopy. (a) Thesequence to use total spin coherence transfer echoes to

Weitekamp, D.P.

2014-01-01T23:59:59.000Z

9

Theinfluence of a hierarchical porous carbon network on the coherent dynamics of a nanoconfined room temperature ionic liquid: A neutron spin echo and atomistic simulation investigation  

SciTech Connect (OSTI)

The molecular-scale dynamic properties of the room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, or [C4mim+ ][Tf2N ], confined in hierarchical microporous mesoporous carbon, were investigated using neutron spin echo (NSE) and molecular dynamics (MD) simulations. Both NSE and MD reveal pronounced slowing of the overall collective dynamics, including the presence of an immobilized fraction of RTIL at the pore wall, on the time scales of these approaches. A fraction of the dynamics, corresponding to RTIL inside 0.75 nm micropores located along the mesopore surfaces, are faster than those of RTIL in direct contact with the walls of 5.8 nm and 7.8 nm cylindrical mesopores. This behavior is ascribed to the near-surface confined-ion density fluctuations resulting from the ion ion and ion wall interactions between the micropores and mesopores as well as their confinement geometries. Strong micropore RTIL interactions result in less-coordinated RTIL within the micropores than in the bulk fluid. Increasing temperature from 296 K to 353 K reduces the immobilized RTIL fraction and results in nearly an order of magnitude increase in the RTIL dynamics. The observed interfacial phenomena underscore the importance of tailoring the surface properties of porous carbons to achieve desirable electrolyte dynamic behavior, since this impacts the performance in applications such as electrical energy storage devices.

Banuelos, Jose Leo [ORNL; Feng, Guang [ORNL; Fulvio, Pasquale F [ORNL; Li, Song [Vanderbilt University, Nashville; Rother, Gernot [ORNL; Arend, Nikolas [ORNL; Faraone, Antonio [National Institute of Standards and Technology (NIST); Dai, Sheng [ORNL; Cummings, Peter T [ORNL; Wesolowski, David J [ORNL

2014-01-01T23:59:59.000Z

10

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

11

Electrically detected spin echoes of donor nuclei in silicon  

E-Print Network [OSTI]

The ability to probe the spin properties of solid state systems electrically underlies a wide variety of emerging technology. Here, we extend electrical readout of the nuclear spin states of phosphorus donors in silicon to the coherent regime with modified Hahn echo sequences. We find that, whilst the nuclear spins have electrically detected phase coherence times exceeding 2 ms, they are nonetheless limited by the artificially shortened lifetime of the probing donor electron.

McCamey, D R; Morley, G W; van Tol, J

2011-01-01T23:59:59.000Z

12

Dynamic neutron scattering on incoherent systems using efficient resonance spin flip techniques  

SciTech Connect (OSTI)

We have performed numerical ray-tracing Monte-Carlo-simulations of incoherent dynamic neutron scattering experiments. We intend to optimize the efficiency of incoherent measurements depending on the fraction of neutrons scattered without and with spin flip at the sample. In addition to conventional spin echo, we have numerically and experimentally studied oscillating intensity techniques. The results point out the advantages of these different spin echo variants and are an important prerequisite for neutron resonance spin echo instruments like RESEDA (FRM II, Munich), to choose the most efficient technique depending on the scattering vector range and the properties of the sample system under study.

Hussler, Wolfgang [Heinz Maier-Leibnitz Zentrum, Technische Universitt Mnchen, D-85748 Garching, Germany and Physik-Department E21, Technische Universitt Mnchen, D-85748 Garching (Germany); Kredler, Lukas [Physik-Department E21, Technische Universitt Mnchen, D-85748 Garching (Germany)

2014-05-15T23:59:59.000Z

13

Pulsed Nuclear Magnetic Resonance: Spin Echoes MIT Department of Physics  

E-Print Network [OSTI]

Pulsed Nuclear Magnetic Resonance: Spin Echoes MIT Department of Physics (Dated: February 5, 2014) In this experiment, the phenomenon of Nuclear Magnetic Resonance (NMR) is used to determine the magnetic moments-factor in atomic spectroscopy and is given by g = (µ/µN )/I, (2) and µN is the nuclear magneton, e /2mp

Seager, Sara

14

E-Print Network 3.0 - alamethicin electron spin-echo Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

5 > >> 1 Alamethicin Topology in Phospholipid Membranes by Oriented Solid-state NMR and EPR Spectroscopies: a Comparison Summary: paramagnetic resonance. ESEEM electron spin echo...

15

Spin in the Neutron | Jefferson Lab  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Spin in the Neutron NEWPORT NEWS, Va. - Puzzling out the source of proton and neutron spin is part of the ongoing experimental effort at Jefferson Lab to understand their structure...

16

Superconducting magnetic Wollaston prism for neutron spin encoding  

SciTech Connect (OSTI)

A magnetic Wollaston prism can spatially split a polarized neutron beam into two beams with different neutron spin states, in a manner analogous to an optical Wollaston prism. Such a Wollaston prism can be used to encode the trajectory of neutrons into the Larmor phase associated with their spin degree of freedom. This encoding can be used for neutron phase-contrast radiography and in spin echo scattering angle measurement (SESAME). In this paper, we show that magnetic Wollaston prisms with highly uniform magnetic fields and low Larmor phase aberration can be constructed to preserve neutron polarization using high temperature superconducting (HTS) materials. The Meissner effect of HTS films is used to confine magnetic fields produced electromagnetically by current-carrying HTS tape wound on suitably shaped soft iron pole pieces. The device is cooled to ?30 K by a closed cycle refrigerator, eliminating the need to replenish liquid cryogens and greatly simplifying operation and maintenance. A HTS film ensures that the magnetic field transition within the prism is sharp, well-defined, and planar due to the Meissner effect. The spin transport efficiency across the device was measured to be ?98.5% independent of neutron wavelength and energizing current. The position-dependent Larmor phase of neutron spins was measured at the NIST Center for Neutron Research facility and found to agree well with detailed simulations. The phase varies linearly with horizontal position, as required, and the neutron beam shows little depolarization. Consequently, the device has advantages over existing devices with similar functionality and provides the capability for a large neutron beam (20 mm 30 mm) and an increase in length scales accessible to SESAME to beyond 10 ?m. With further improvements of the external coupling guide field in the prototype device, a larger neutron beam could be employed.

Li, F., E-mail: fankli@indiana.edu; Parnell, S. R.; Wang, T.; Baxter, D. V. [Center for Exploration of Energy and Matter, Indiana University, Bloomington, Indiana 47408 (United States)] [Center for Exploration of Energy and Matter, Indiana University, Bloomington, Indiana 47408 (United States); Hamilton, W. A. [Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States)] [Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States); Maranville, B. B. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)] [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Semerad, R. [Ceraco Ceramic Coating GmbH, Ismaning 85737 (Germany)] [Ceraco Ceramic Coating GmbH, Ismaning 85737 (Germany); Cremer, J. T. [Adelphi Technology Inc., Redwood City, California 94063 (United States)] [Adelphi Technology Inc., Redwood City, California 94063 (United States); Pynn, R. [Center for Exploration of Energy and Matter, Indiana University, Bloomington, Indiana 47408 (United States) [Center for Exploration of Energy and Matter, Indiana University, Bloomington, Indiana 47408 (United States); Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States)

2014-05-15T23:59:59.000Z

17

Segmentation of Spin-Echo MRI brain images: a comparison study of Crisp and Fuzzy algorithms  

E-Print Network [OSTI]

This thesis presents a scheme for segmenting Spin-Echo MRI brain images based on Fuzzy C-Mean (FCM) clustering techniques. This scheme consists of feature extraction, feature conditioning or evaluation, and thresholded FCM clustering. Feature...

Chung, Maranatha

2012-06-07T23:59:59.000Z

18

Spin Waves and Neutron Scattering  

Science Journals Connector (OSTI)

A review is given of the problems in this field and of the possibilities opened up by the fact that neutron scattering gives access to the time?dependent spin?correlation function in magnets over virtually the whole range of q t and T. New experimental results are given in connection with magnon energy linewidth and renormalization and some data are presented for the spin?wave stiffness of bcc 3d transition?metal alloys as a function of electron concentration showing effects explained by the electronic density?of?states curve. It is pointed out that the ground?state fluctuations of magnets give rise to effects in the formulas for neutron scattering.

R. D. Lowde

1965-01-01T23:59:59.000Z

19

Isotropic 3D fast spin-echo imaging versus standard 2D imaging at 3.0 T of the kneeimage quality and diagnostic performance  

E-Print Network [OSTI]

SB (2007) High-resolution 3D cartilage imaging with IDEALMa Thomas M. Link Isotropic 3D fast spin-echo imaging versusintermediate-weighted (IM-w) 3D fast spin-echo (FSE) se-

2009-01-01T23:59:59.000Z

20

Neutron Scattering and Ordering of Nuclear Spins  

Science Journals Connector (OSTI)

The ordering of nuclear spins takes place at extremely low temperatures because of the weakness of the interactions between their magnetic moments. Neutron scattering is the traditional and unique method to ... (...

M. Steiner

2004-06-01T23:59:59.000Z

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.


21

Neutron Spin Resonance in Iron-based Superconductors | The Ames...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Neutron Spin Resonance in Iron-based Superconductors The propagation of a novel magnetic excitation in the superconducting state, called a spin resonance, has been observed in iron...

22

Neutron single target spin asymmetries in SIDIS  

SciTech Connect (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

23

Long-lived selective spin echoes in dipolar solids under periodic and aperiodic pi-pulse trains  

E-Print Network [OSTI]

The application of Carr-Purcell-Meiboom-Gill (CPMG) $\\pi-$trains for dynamically decoupling a system from its environment has been extensively studied in a variety of physical systems. When applied to dipolar solids, recent experiments have demonstrated that CPMG pulse trains can generate long-lived spin echoes. While there still remains some controversy as to the origins of these long-lived spin echoes under the CPMG sequence, there is a general agreement that pulse errors during the $\\pi-$pulses are a necessary requirement. In this work, we develop a theory to describe the spin dynamics in dipolar coupled spin-1/2 system under a CPMG($\\phi_{1},\\phi_{2}$) pulse train, where $\\phi_{1}$ and $\\phi_{2}$ are the phases of the $\\pi-$pulses. From our theoretical framework, the propagator for the CPMG($\\phi_{1},\\phi_{2}$) pulse train is equivalent to an effective ``pulsed'' spin-locking of single-quantum coherences with phase $\\pm\\frac{\\phi_{2}-3\\phi_{1}}{2}$, which generates a periodic quasiequilibrium that corresponds to the long-lived echoes. Numerical simulations, along with experiments on both magnetically dilute, random spin networks found in C$_{60}$ and C$_{70}$ and in non-dilute spin systems found in adamantane and ferrocene, were performed and confirm the predictions from the proposed theory.

Clark D. Ridge; Lauren F. O'Donnell; Jamie D. Walls

2013-12-04T23:59:59.000Z

24

Polarized 3He for Neutron Spin Filters and MRI Applications  

Office of Scientific and Technical Information (OSTI)

and the associated grant to Indiana University was to extend the technique of polarized neutron scattering by the development and application of polarized 3He-based neutron spin...

25

NEUTRON SCATTERING EVIDENCE FOR A SPIN-PEIERLS  

E-Print Network [OSTI]

NEUTRON SCATTERING EVIDENCE FOR A SPIN-PEIERLS GROUND STATE IN (TMTTF)2PF6 J.P. POUGET, P. FOURY results · magnetic caracterisation of the samples used · neutron scattering detection of the SP;elastic neutron scattering evidence of SP superlattice reflexions in (TMTTF)2PF6 (H12) Laboratoire Léon

Paris-Sud 11, Université de

26

Phase relationship between the long-time beats of free induction decays and spin echoes in solids  

Science Journals Connector (OSTI)

Recent theoretical work on the role of microscopic chaos in the dynamics and relaxation of many-body quantum systems has made several experimentally confirmed predictions about the systems of interacting nuclear spins in solids, focusing in particular on the shapes of spin echo responses measured by nuclear magnetic resonance. These predictions were based on the idea that the transverse nuclear spin decays evolve in a manner governed at long times by the slowest decaying eigenmode of the quantum system, analogous to a chaotic resonance in a classical system. The present paper extends the above investigations both theoretically and experimentally. On the theoretical side, the notion of chaotic eigenmodes is used to make predictions about the relationships between the long-time oscillation phase of the nuclear free induction decay and the amplitudes and phases of spin echoes. On the experimental side, the above predictions are tested for the nuclear spin decays of 19F in CaF2 crystals and 129Xe in frozen xenon. Good agreement between the theory and the experiment is found.

E. G. Sorte; B. V. Fine; B. Saam

2012-05-17T23:59:59.000Z

27

E-Print Network 3.0 - acquisition spin echo Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

point for data... collected in a single TR with CPMG (a) or a mixed-CPMG (b) echo train. Blue lines correspond to a b-value0 Source: National Institutes of Health,...

28

The electron-spin-nuclear-spin interaction studied by polarized neutron scattering  

Science Journals Connector (OSTI)

The directional properties of electron-proton spin interaction in an external magnetic field give rise to an anisotropic distribution of the intensity of polarized neutron scattering from dynamically polarized protons of radical molecules in solution.

Stuhrmann, H.B.

2007-11-01T23:59:59.000Z

29

Electron spin resonance and electron spin echo modulation studies on radiation-induced silver agglomeration in a SAPO-42 molecular sieve: A comparison with isostructural zeolite A  

SciTech Connect (OSTI)

This study focuses on paramagnetic silver species produced by [gamma]-radiolysis of a silver silicoaluminophosphate-42 (Ag-SAPO-42) molecular sieve. Electron spin resonance and electron spin echo modulation spectroscopies have been used to study the structure, location, and coordination of silver adducts and clusters stabilized in dehydrated SAPO-42 and exposed to methanol and ammonia. It was found that in dehydrated AG-SAPO-42, small silver clusters are formed with very low yield, whereas, in AgNa-A, Ag[sub 3][sup 2+] or AG[sub 6][sup b+] clusters are efficiently stabilized. The less restricted mobility of Ag[sup 0] in SAPO-42 due to its lower cation capacity is postulated to explain the observed differences. In the presence of methanol and ammonia in the molecular sieve cages, the differences are less significant. The major paramagnetic products of radiolysis in both SAPO-42 and type A molecular sieves are silver methoxy radicals (methanol adsorbed) or silver-ammonia adducts (ammonia adsorbed). They are located in [alpha]-cages, although the electron spin echo modulation results suggest some differences in location, possibly due to a different distribution of negative charge between the aluminophosphate and aluminosilicate frameworks. 22 refs., 7 figs., 1 tab.

Michalik, J.; Sadlo, J. (Inst. of Nuclear Chemistry and Technology, Warsaw (Poland)); Kevan, L.; Zamadics, M. (Univ. of Houston, TX (United States))

1993-10-07T23:59:59.000Z

30

NARROW ATOMIC FEATURES FROM RAPIDLY SPINNING NEUTRON STARS  

SciTech Connect (OSTI)

Neutron stars spinning at moderate rates ({approx}300-600 Hz) become oblate in shape and acquire a nonzero quadrupole moment. In this paper, we calculate the profiles of atomic features from such neutron stars using a ray-tracing algorithm in the Hartle-Thorne approximation. We show that line profiles acquire cores that are much narrower than the widths expected from pure Doppler effects for a large range of observer inclinations. As a result, the effects of both the oblateness and the quadrupole moments of neutron stars need to be taken into account when aiming to measure neutron-star radii from rotationally broadened lines. Moreover, the presence of these narrow cores substantially increases the likelihood of detecting atomic lines from rapidly spinning neutron stars.

Bauboeck, Michi; Psaltis, Dimitrios; Oezel, Feryal, E-mail: mbaubock@email.arizona.edu, E-mail: dpsaltis@email.arizona.edu, E-mail: fozel@email.arizona.edu [Astronomy Department, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)] [Astronomy Department, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

2013-04-01T23:59:59.000Z

31

Neutron scattering studies of spin?glass alloys  

Science Journals Connector (OSTI)

Neutron diffraction investigations of binary alloys such as Cu?Mn beginning with the earliest reported measurements in 1957 show no evidence of any long range magnetic order except for the broad short range order peaks at the (1 1/2 0) type positions attributed to both atomic and magnetic short range ordering in alloys containing more than about 1015 at.% Mn. The current interest in spin glasses is focused on the theoretical possibility of a magnetic phase transition to the spin glass state in the dilute random substitutional alloys. Recently neutron scatteringmeasurements have been attempted to study the dynamics of spins in the alloys with a view to understanding the nature of the processes leading to the spin glass state. Small angle neutron scatteringmeasurements on Au?Fe alloys with Fe concentrations below the percolation threshold for ferromagnetism show a series of q?dependent maxima in the total scattering intensity suggesting a continuum of freezing temperatures. Other measurements employing energy analysis by the time?of?flight technique at somewhat larger qs on the same and other alloys such as Cu?Mn Pd?Mn show a broad quasi?elastic paramagnetic spectrum at high temperatures whose energy width decreases with decreasing temperature apparently goes through a minimum especially at the higher qs but always remains finite as T?0 K. The intensity of the quasi?elastic scattering however diminishes progressively below some temperature with a simultaneous continuous increase of the elastic peak intensity. Although the implications of the recent phase transition theories of spin glasses to the dynamics of spins at finite scattering vectors are not entirely clear the present neutron scattering results appear not inconsistent with the alternative picture of a continuous process of freezing of spins occurring at least over a finite temperature range.

A. P. Murani

1978-01-01T23:59:59.000Z

32

Neutron Scattering Investigation on Quantum Spin System SrCu2(BO3)2  

Science Journals Connector (OSTI)

......research-article Articles Neutron Scattering Investigation on Quantum Spin...review the zero field inelastic neutron scattering results obtained by using both the thermal and cold neutron triple axis instrument. The......

Kazuhisa Kakurai; Katsuyuki Nukui; Naofumi Aso; Masakazu Nishi; Hiroaki Kadowaki; Hiroshi Kageyama; Yutaka Ueda; L.-P. Regnault; O. Cpas

2005-05-01T23:59:59.000Z

33

SPIN-DEPENDENT SCATTERING LENGTHS OF SLOW NEUTRONS WITH NUCLEI BY PSEUDOMAGNETIC MEASUREMENTS  

E-Print Network [OSTI]

L-263 SPIN-DEPENDENT SCATTERING LENGTHS OF SLOW NEUTRONS WITH NUCLEI BY PSEUDOMAGNETIC MEASUREMENTS vu par les noyaux. Abstract. - The spin-dependent scattering length of slow neutrons by the nuclei 23 can be of practical importance in many thermal neutron scattering experiments. A new method, called

Boyer, Edmond

34

Spin-dependent scattering and absorption of thermal neutrons on dynamically polarized nuclei  

E-Print Network [OSTI]

957 Spin-dependent scattering and absorption of thermal neutrons on dynamically polarized nuclei H neutrons and polarized nuclei have been used to measure spin-dependent scattering lengths and absorption cross sections of slow (S-wave) neutrons on nuclei. In order to obtain those scattering lengths

Paris-Sud XI, Université de

35

Electron spin resonance and electron spin-echo modulation study of paramagnetic Rh species generated in Ca-Y and Na-Y zeolites  

SciTech Connect (OSTI)

Paramagnetic Rh species generated in RhNa-Y and RhCa-Y zeolites after various treatments were characterized by using electron spin resonance (ESR) and electron spin-echo modulation (ESEM) spectroscopies. Activation in flowing oxygen at 500/sup 0/C ..beta..-hydrogen a considerable amount of Rh(II) located in site I in the hexagonal prism of the zeolite structure for 3 wt % Rh in RhNa-Y zeolite. Samples of 1 wt % Rh in RhNa-Y and RhCa-Y did not show any paramagnetic signals. Adsorption of various adsorbates such as water, ammonia, methanol, carbon monoxide, and oxygen on activated samples induced a considerable increase in the ESR intensities. Adsorption of oxygen and carbon monoxide yields the corresponding adducts which are located in the ..cap alpha..-cage of the zeolite structure. Hydration generated a species which is coordinated to three water molecules. Adsorption of methanol on RhNa-Y generated a species H2 which is also formed after reduction of RhNa-Y with H/sub 2/, suggesting that the methanol molecule undergoes a reaction to generate products which further reduce Rh(III) species in the ..beta..-cage of the zeolite structure to Rh(II). No significant differences were observed between RhNa-Y and RhCa-Y except for the formation of different Rh(II) species after methanol adsorption in RhCa-Y and the generation of a larger amount of Rh(II) in site I in RhNa-Y. These results are compared to previously obtained data in RhNa-X and RhCa-X to account for the effect of the cocations and the Si/Al ratio on the generation of Rh(II) species in zeolites.

Goldfarb, D.; Kevan, L.

1987-04-15T23:59:59.000Z

36

Neutron halo and spin-orbit splitting in some neutron-rich nuclei  

Science Journals Connector (OSTI)

The density-dependent relativistic mean-field theory with ?, ?, and ? mesons, as a parameter-free calculation, has been used to study the ground-state properties of Be12,14, Ne30,32, Ca60,62, and Zr122,124. A special emphasis is placed on the influence of the ? tensor coupling on the neutron halo and on the spin-orbit splitting. It is shown for the first time that the inclusion of the ? tensor coupling will lead to the isospin-dependent spin-orbit splitting although the binding energy and the radius of these nuclei are insensitive to it.

Zhongzhou Ren; M. Mittig; Baoqiu Chen; Zhongyu Ma; G. Auger; Gongou Xu

1995-10-01T23:59:59.000Z

37

Transverse and longitudinal polarized-neutron, polarized-93Nb scattering, and the tensor spin-spin potential  

Science Journals Connector (OSTI)

Spin-spin cross sections were measured for 7.5-MeV polarized neutrons incident on cryogenically polarized Nb93. Measurements were made with spin orientations transverse and longitudinal to the beam direction, yielding ?Tss=-5.25.3 mb and ?Lss=-2.26.9 mb, respectively. The results are consistent with recent valence-nucleon folding model calculations. The tensor spin-spin potential is found to be small, V12=-67190 keV. Volume integrals of spin-spin potentials are derived from depolarization and transmission experiments on C13, N15, Al27, and Nb93. The results for the central spin-spin potential are shown to be consistent with the folding model predictions.

J. P. Soderstrum; C. R. Gould; D. G. Haase; N. R. Roberson; M. B. Schneider; L. W. Seagondollar

1992-01-01T23:59:59.000Z

38

Asterix is a reflectometer/diffractometer/grazing-incidence-SANS/SESAME-enabled-SANS spectrometer that is primarily used for experiments or neutron scattering  

E-Print Network [OSTI]

that is primarily used for experiments or neutron scattering techniques requiring polarized neutron beams detector arm is readily configurable for polarization or energy analysis of the scattered neutron beam be translated in the horizontal and vertical directions. Neutron detector (Spin Echo Scattering Angle

39

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

40

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

E-Print Network [OSTI]

We have 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. The spin rotator does not change the kinetic energy of the neutrons and leaves the neutron beam phase space unchanged to high precision. 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 3He neutron spin filters. The efficiency of the spin rotator was measured to be 98.0+/-0.8% on resonance for neutron energies from 3.3 to 18.4 meV over the full phase space of the beam. As an example of the application of this device to an experiment we describe the integration of the RF spin rotator into an apparatus to search for the small parity-violating asymmetry A_gamma in polarized cold neutron capture on para-hydrogen by the NPDGamma collaboration at LANSCE.

P. -N. Seo; L. Barron-Palos; J. D. Bowman; T. E. Chupp; C. Crawford; M. Dabaghyan; M. Dawkins; S. J. Freedman; T. Gentile; M. T. Gericke; R. C. Gillis; G. L. Greene; F. W. Hersman; G. L. Jones; M. Kandes; S. Lamoreaux; B. Lauss; M. B. Leuschner; R. Mahurin; M. Mason; J. Mei; G. S. Mitchell; H. Nann; S. A. Page; S. I. Penttila; W. D. Ramsay; A. Salas Bacci; S. Santra; M. Sharma; T. B. Smith; W. M. Snow; W. S. Wilburn; H. Zhu

2007-10-15T23:59:59.000Z

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.


41

Neutron-Scattering Evidence for a Spin-Peierls Ground State in (TMTTF)2PF6  

Science Journals Connector (OSTI)

(TMTTF)2X, with X=PF6, exhibits, at TSP..., a spin-Peierls transition. Below TSP elastic neutron scattering measurements performed on large protonated and deuterated...SP decreases by 30% while the charge orderin...

J.-P. Pouget; P. Foury-Leylekian; D. Le Bolloch

2006-02-01T23:59:59.000Z

42

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

SciTech Connect (OSTI)

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

Ono, K., E-mail: kanta.ono@kek.jp; Inami, N.; Saito, K.; Takeichi, Y.; Kawana, D.; Yokoo, T.; Itoh, S. [Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); Yano, M.; Shoji, T.; Manabe, A.; Kato, A. [Toyota Motor Corporation, Toyota, Aichi 471-8571 (Japan); Kaneko, Y. [Toyota Central R and D Labs. Inc., Aichi 480-1192 (Japan)

2014-05-07T23:59:59.000Z

43

Large volume high-pressure cell for inelastic neutron scattering W. Wang, D. A. Sokolov, A. D. Huxley, and K. V. Kamenev  

E-Print Network [OSTI]

Large volume high-pressure cell for inelastic neutron scattering W. Wang, D. A. Sokolov, A. D for inelastic neutron scattering measurements of quantum fluids and solids Rev. Sci. Instrum. 84, 015101 (2013) TOF-SEMSANS--Time-of-flight spin-echo modulated small-angle neutron scattering J. Appl. Phys. 112

Hall, Christopher

44

Impact of precession on aligned-spin searches for neutron-star--black-hole binaries  

E-Print Network [OSTI]

The inclusion of aligned-spin effects in gravitational-wave search pipelines for neutron-star--black-hole binary coalescence has been shown to increase the astrophysical reach with respect to search methods where spins are neglected completely, under astrophysically reasonable assumptions about black-hole spins. However, theoretical considerations and population synthesis models suggest that many of these binaries may have a significant misalignment between the black-hole spin and the orbital angular momentum, which could lead to precession of the orbital plane during the inspiral and a consequent loss in detection efficiency if precession is ignored. This work explores the effect of spin misalignment on a search pipeline that completely neglects spin effects and on a recently-developed pipeline that only includes aligned-spin effects. Using synthetic but realistic data, which could reasonably represent the first scientific runs of advanced-LIGO detectors, the relative sensitivities of both pipelines are shown for different assumptions about black-hole spin magnitude and alignment with the orbital angular momentum. Despite the inclusion of aligned-spin effects, the loss in signal-to-noise ratio due to precession can be as large as $40\\%$, but this has a limited impact on the overall detection rate: even if precession is a predominant feature of neutron-star--black-hole binaries, an aligned-spin search pipeline can still detect at least half of the signals compared to an idealized generic precessing search pipeline.

Tito Dal Canton; Andrew P. Lundgren; Alex B. Nielsen

2014-11-25T23:59:59.000Z

45

The Spin Periods and Rotational Profiles of Neutron Stars at Birth  

Science Journals Connector (OSTI)

We present results from an extensive set of one- and two-dimensional radiation-hydrodynamic simulations of the supernova core-collapse, bounce, and postbounce phases and focus on the proto-neutron star (PNS) spin periods and rotational profiles as a function of initial iron core angular velocity, degree of differential rotation, and progenitor mass. For the models considered, we find a roughly linear mapping between initial iron core rotation rate and PNS spin. The results indicate that the magnitude of the precollapse iron core angular velocities is the single most important factor in determining the PNS spin. Differences in progenitor mass and degree of differential rotation lead only to small variations in the PNS rotational period and profile. Based on our calculated PNS spins at ~200-300 ms after bounce and assuming angular momentum conservation, we estimate final neutron star rotation periods. We find periods of 1 ms and shorter for initial central iron core periods of 10 s. This is appreciably shorter than what previous studies have predicted and is in disagreement with current observational data from pulsar astronomy. After considering possible spin-down mechanisms that could lead to longer periods, we conclude that there is no mechanism that can robustly spin down a neutron star from ~1 ms periods to the "injection" periods of tens to hundreds of milliseconds observed for young pulsars. Our results indicate that, given current knowledge of the limitations of neutron star spin-down mechanisms, precollapse iron cores must rotate with periods of around 50-100 s to form neutron stars with periods generically near those inferred for the radio pulsar population.

Christian D. Ott; Adam Burrows; Todd A. Thompson; Eli Livne; Rolf Walder

2006-01-01T23:59:59.000Z

46

Spin polarized neutron matte and magnetic susceptibility within the Brueckner-Hartree-Fock approximation  

E-Print Network [OSTI]

The Brueckner--Hartree--Fock formalism is applied to study spin polarized neutron matter properties. Results of the total energy per particle as a function of the spin polarization and density are presented for two modern realistic nucleon-nucleon interactions, Nijmegen II and Reid93. We find that the dependence of the energy on the spin polarization is practically parabolic in the full range of polarizations. The magnetic susceptibility of the system is computed. Our results show no indication of a ferromagnetic transition which becomes even more difficult as the density increases.

I. Vidaa; A. Polls; A. Ramos

2001-11-19T23:59:59.000Z

47

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

Science Journals Connector (OSTI)

A method to map spin-resolved electron distribution from combined polarized neutron and X-ray diffraction is described and applied for the first time to a molecular magnet and it is shown that spin up density is 5% more contracted than spin down density.

Deutsch, M.

2014-04-14T23:59:59.000Z

48

Outflows from accretion disks formed in neutron star mergers: effect of black hole spin  

E-Print Network [OSTI]

The accretion disk that forms after a neutron star merger is a source of neutron-rich ejecta. The ejected material contributes to a radioactively-powered electromagnetic transient, with properties that depend sensitively on the composition of the outflow. Here we investigate how the spin of the black hole remnant influences mass ejection on the thermal and viscous timescales. We carry out two-dimensional, time-dependent hydrodynamic simulations of merger remnant accretion disks including viscous angular momentum transport and approximate neutrino self-irradiation. The gravity of the spinning black hole is included via a pseudo-Newtonian potential. We find that a disk around a spinning black hole ejects more mass, up to a factor of several, relative to the non-spinning case. The enhanced mass loss is due to energy release by accretion occurring deeper in the gravitational potential, raising the disk temperature and hence the rate of viscous heating in regions where neutrino cooling is ineffective. The mean electron fraction of the outflow increases moderately with BH spin due to a highly-irradiated (though not neutrino-driven) wind component. While the bulk of the ejecta is still very neutron-rich, thus generating heavy r-process elements, the leading edge of the wind contains a small amount of Lanthanide-free material. This component can give rise to a ~1 day blue optical `bump' in a kilonova light curve, even in the case of prompt BH formation, which may facilitate its detection.

Rodrigo Fernndez; Daniel Kasen; Brian D. Metzger; Eliot Quataert

2014-09-15T23:59:59.000Z

49

Probing spin frustration in high-symmetry magnetic nanomolecules by inelastic neutron scattering  

Science Journals Connector (OSTI)

Low temperature inelastic neutron scattering studies have been performed to characterize the low energy magnetic excitation spectrum of the magnetic nanomolecule {Mo72Fe30}. This unique highly symmetric cluster features spin frustration and is one of the largest discrete magnetic molecules studied to date by inelastic neutron scattering. The 30s=5?2 FeIII ions, embedded in a spherical polyoxomolybdate molecule, occupy the vertices of an icosidodecahedron and are coupled via nearest-neighbor antiferromagnetic interactions. The overall energy scale of the excitation and the gross features of the temperature dependence of the observed neutron scattering are explained by a quantum model of the frustrated spin cluster. However, no satisfactory theoretical explanation is yet available for the observed magnetic field dependence.

V. O. Garlea; S. E. Nagler; J. L. Zarestky; C. Stassis; D. Vaknin; P. Kgerler; D. F. McMorrow; C. Niedermayer; D. A. Tennant; B. Lake; Y. Qiu; M. Exler; J. Schnack; M. Luban

2006-01-23T23:59:59.000Z

50

Competing interactions at the interface between ferromagnetic oxides revealed by spin-polarized neutron reflectometry  

Science Journals Connector (OSTI)

We have investigated the magnetization profiles in superlattices composed of the two ferromagnets La0.7Sr0.3MnO3 and SrRuO3 using spin-polarized neutron reflectometry. In combination with magnetometry, the neutron data indicate a noncollinear spin configuration where orientation of the Ru moments changes from in plane at the interface to out of plane deep inside the SrRuO3 layers. The spin structure originates in a competition between antiferromagnetic exchange interactions of Mn and Ru moments across the interface, and the magnetocrystalline anisotropy of the Ru moments, and it is closely related to the exchange spring structures previously observed in multilayers composed of ferromagnetic elements and alloys.

J.-H. Kim; I. Vrejoiu; Y. Khaydukov; T. Keller; J. Stahn; A. Rhm; D. K. Satapathy; V. Hinkov; B. Keimer

2012-11-08T23:59:59.000Z

51

Two-pulse stimulated echo in magnets  

E-Print Network [OSTI]

The results of experimental study of two-pulse stimulated echo in ferromagnets of two types are presented. Ferromagnet Co and half-metal Co MnSi 2, in which a single-pulse echo formed by the distortion mechanism of the fronts of exciting pulse is also observed, are classified among the first type. Lithium ferrite and intermetal compound MnSb characterized by the absence of single-pulse echo in them - belong to the second type. For signals of two-pulse stimulated echo in the materials of the first type a short time and a long time of relaxations are observed. The short time is about the order of value shorter less than the spin-spin relaxation time. The long time is close to the transverse relaxation time of single-pulse echo formed by the distortion mechanism. The mechanisms that provide the possible interpretations of the peculiarities of the processes of nuclear magnetic relaxation are discussed.

Zviadadze, M D; Gegechkori, T O; Akhalkatsi, A M; Gavasheli, T A

2012-01-01T23:59:59.000Z

52

Exact analysis of polycrystalline electron spin echo envelope modulation including mutual nuclear arrangements and quadrupole interactions and its application to methyl radicals in irradiated crystals of lithium acetate dihydrate  

Science Journals Connector (OSTI)

The method of exact analysis including mutual nuclear arrangements and quadrupole interactions is developed for electron spin echo envelope modulation (ESEM) from polycrystalline samples using the formulation in an arbitrary laboratory coordinate system which makes it possible to perform an exact angular integration. In order to assess polycrystalline ESEM by comparing with electron nuclear double resonance(ENDOR) data the method is applied to analyze deuterium hyperfine modulation on the two?pulse electron spin echo (ESE) envelope decay observed for methyl radicals radiolytically produced in CD3COOLi???2H2O and CH3COOLi???2D2O. The results are totally consistent with our previous study by single crystal1H ENDOR. Through this application importance of the nuclear quadrupole term is also shown based on the exact method. The rigid deuterons in the water of crystallization show a marked quadrupole effect as compared with those in the freely rotating CD3 group. The contributions from the distant nuclei to the modulation pattern are also studied by the exact method using the crystallographic data. We have further clarified that the origin of the disagreement of a previous Li ESEM with our ENDOR is mainly in the use of a unit spin density on the spin probe despite its reduction by delocalization to the environment.

Machio Iwasaki; Kazumi Toriyama

1985-01-01T23:59:59.000Z

53

Portable Neutron Sensors for Emergency Response Operations  

SciTech Connect (OSTI)

This article presents the experimental work performed in the area of neutron detector development at the Remote Sensing LaboratoryAndrews 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

54

Inelastic neutron scattering study of a quantum spin trimer  

Science Journals Connector (OSTI)

We present an inelastic neutron scattering (INS) study of the excitation spectrum of a quantum S=1?2 equilateral Heisenberg trimer, Cu3(O2C16H23)61.2C6H12. The magnetic properties of the system can be described by an ensemble of independent equilateral triangles of S=1?2 Cu2+ ions. With antiferromagnetic Heisenberg coupling, the ground state of each trimer is a degenerate pair of S=1?2 doublets, with a quartet S=3?2 excited state. Previous bulk measurements led to an estimate for the excitation energy of 28meV. Here, we report INS measurements that can provide a direct measurement of magnetic excitation energies. These measurements are challenging since inter- and intramolecular vibrational modes associated with the organic ligands are at frequencies similar to the magnetic excitations. Measurements on a nonmagnetic compound with the same ligands as well as the temperature dependence of the neutron scattering cross section are used to identify the vibrational modes. This leads to an identification of the magnetic excitation energy as being approximately 37meV at T=10K, with a gradual softening with increasing temperature.

M. B. Stone; F. Fernandez-Alonso; D. T. Adroja; N. S. Dalal; D. Villagrn; F. A. Cotton; S. E. Nagler

2007-06-25T23:59:59.000Z

55

Coalescing neutron stars - a step towards physical models III. Improved numerics and different neutron star masses and spins  

E-Print Network [OSTI]

(Abridged) In this paper we present a compilation of results from our most advanced neutron star merger simulations, including a description of the employed numerical procedures and a more complete overview over a large number of computed models. The three-dimensional hydrodynamic simulations were done with a code based on the Piecewise Parabolic Method with up to five levels of nested Cartesian grids. The simulations are basically Newtonian, but gravitational-wave emission and the corresponding back-reaction are taken into account. The use of a physical nuclear equation of state allows us to follow the thermodynamic history of the stellar medium and to compute the energy and lepton number loss due to the emission of neutrinos. The computed models differ concerning the neutron star masses and mass ratios, the neutron star spins, the numerical resolution expressed by the cell size of the finest grid and the number of grid levels, and the calculation of the temperature from the solution of the entropy equation instead of the energy equation. Our simulations show that the details of the gravitational-wave emission are still sensitive to the numerical resolution, even in our highest-quality calculations. The amount of mass which can be ejected from neutron star mergers depends strongly on the angular momentum of the system. Our results do not support the initial conditions of temperature and proton-to-nucleon ratio assumed in recent work for producing a solar r-process pattern for nuclei around and above the A approx 130 peak. The improved models confirm our previous conclusion that gamma-ray bursts are not powered by neutrino emission during the dynamical phase of the merging of two neutron stars.

M. Ruffert; H. -Th. Janka

2001-06-13T23:59:59.000Z

56

Outflows from accretion disks formed in neutron star mergers: effect of black hole spin  

E-Print Network [OSTI]

The accretion disk that forms after a neutron star merger is a source of neutron-rich ejecta. The ejected material contributes to a radioactively-powered electromagnetic transient, with properties that depend sensitively on the composition of the outflow. Here we investigate how the spin of the black hole remnant influences mass ejection on the thermal and viscous timescales. To this end, we carry out two-dimensional, time-dependent hydrodynamic simulations of merger remnant accretion disks including viscous angular momentum transport and approximate neutrino self-irradiation. The gravity of the spinning black hole is included via a pseudo-Newtonian potential. We find that a disk around a spinning black hole ejects more mass, up to a factor of several, relative to the non-spinning case. The enhanced mass loss is due to energy release by accretion occurring deeper in the gravitational potential, raising the disk temperature and hence the rate of viscous heating in regions where neutrino cooling is ineffective....

Fernndez, Rodrigo; Metzger, Brian D; Quataert, Eliot

2014-01-01T23:59:59.000Z

57

Spin-polarized energy-band structure, conduction-electron polarization, spin densities, and the neutron magnetic form factor of ferromagnetic gadolinium  

Science Journals Connector (OSTI)

Conduction-electron polarization, spin densities, and neutron magnetic scattering in ferromagnetic Gd metal were studied using the spin-polarized augmented-plane-wave (APW) method in a warped-muffin-tin-potential formulation. The spin-up and spin-down bands were found to be very similar in shape to the bands from a paramagnetic calculation, with the exchange splitting proportional to the amount of d character in the bands. It was also found that the conduction-electron spin density determined from the APW wave functions is of mostly d character. This dominance of the d-like wave functions for the spin-dependent interactions is explained by (i) the much greater overlap of the 4f states with the d-like wave functions as compared to the s-p wave functions; (ii) the nearly complete d character of the bands in the region of the Fermi surface. The magnetic form factor was calculated from the conduction-electron spin density and compared with the recent neutron magnetic - form - factor measurement of Moon, Koehler, Cable, and Child. The calculated spin density was found to have the same shape as the "diffuse" density derived by Moon et al. (including a negative but much smaller in magnitude spin density at the c site in the unit cell). After the inclusion of core - polarization effects we conclude that large nonspherical contributions with Y33-Y3-3, and Y40 angular dependence are needed to explain the experimental results.

B. N. Harmon and A. J. Freeman

1974-09-01T23:59:59.000Z

58

Measurements Of Spin Observables In Pseudoscalar-Meson Photo-Production Using Polarized Neutrons In Solid HD  

SciTech Connect (OSTI)

Psuedo-scalar meson photo production measurements have been carried out with longitudinally-polarized neutrons using the circularly and linearly polarized photon beams and the CLAS at Thomas Jefferson National Accelerator Facility (Jlab). The experiment aims to obtain a complete set of spin observables on an efficient neutron target. Preliminary E asymmetries for the exclusive reaction, gamma + n(p)--> pi- + p(p), selecting quasi free neutron kinematics are discussed.

Kageya, Tsuneo

2014-01-01T23:59:59.000Z

59

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

60

Dynamically polarized hydrogen target as a broadband, wavelength-independent thermal neutron spin polarizer  

SciTech Connect (OSTI)

A hydrogen-rich sample with dynamically polarized hydrogen nuclei was tested as a wavelength-independent neutron transmission spin polarizer. The experiment used a modified setup of the dynamic nuclear polarization target station at the GKSS research center. The standard solvent sample at the GKSS DNP station was used. It is 2.8 mm thick and consists of 43.4 wt% water, 54.6 wt% glycerol, and 2 wt% of EHBA-Cr(v) complex. The wavelength of the incident neutrons for the transmission experiment was {lambda} = 8.1 {angstrom} with {Delta}{lambda}/{lambda} = 10%. The polarization of neutron beam after the target sample was analyzed with a supermirror analyzer. A neutron polarization of -52% was achieved at the hydrogen polarization of -69%. Further experiments will test the feasibility of other hydrogen-rich materials, such as methane, as the polarizer. A theoretical calculation shows that a polarized methane target would allow over 95% neutron polarizations with more than 30% transmission.

Zhao, Jinkui [ORNL; Garamus, VM [GKSS Research Center, Germany; Mueller, W [GKSS Research Center, Germany; Willumeit, R [GKSS Research Center, Germany

2005-01-01T23:59:59.000Z

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.


61

Neutron-scattering evidence for a spin-Peierls ground state in ,,TMTTF...2PF6 P. Foury-Leylekian,1  

E-Print Network [OSTI]

Neutron-scattering evidence for a spin-Peierls ground state in ,,TMTTF...2PF6 P. Foury-Leylekian,1 by elastic neutron scattering. The 1 2 , 1 2 , 1 2 superstructure reflection associated with the SP

Paris-Sud 11, Université de

62

Ferromagnetic cluster spin waves in molecular disks studied by inelastic neutron scattering  

Science Journals Connector (OSTI)

Structurally, the two mixed-valence manganese disks Mn7-11 and Mn7-16 differ only in the peripheral ligand but, as a result of a subtle interplay of intramolecular exchange interactions, differ strongly in their magnetic properties, e.g., Mn7-11 possesses a ground-state spin of S=11 and Mn7-16 of S=16. The exchange interactions in the disks were studied by inelastic neutron scattering. The analysis of the Q dependence of the observed magnetic transition intensities reveals that ferromagnetic cluster spin-wave excitations were observed. In this framework, it was possible to successfully model the experimental data and provide a physical understanding of the magnetism in the two disks.

J. Nehrkorn; S. Mukherjee; S. Stuiber; H. Mutka; Th. Strssle; G. Christou; O. Waldmann

2012-10-19T23:59:59.000Z

63

Neutron spin structure with polarized deuterons and spectator proton tagging at EIC  

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

The neutron's deep-inelastic structure functions provide essential information for the flavor separation of the nucleon parton densities, the nucleon spin decomposition, and precision studies of QCD phenomena in the flavor-singlet and nonsinglet sectors. Traditional inclusive measurements on nuclear targets are limited by dilution from scattering on protons, Fermi motion and binding effects, final-state interactions, and nuclear shadowing at x << 0.1. An Electron-Ion Collider (EIC) would enable next-generation measurements of neutron structure with polarized deuteron beams and detection of forward-moving spectator protons over a wide range of recoil momenta (0 < p_R << several 100 MeV in the nucleus rest frame). The free neutron structure functions could be obtained by extrapolating the measured recoil momentum distributions to the on-shell point. The method eliminates nuclear modifications and can be applied to polarized scattering, as well as to semi-inclusive and exclusive final states. We review the prospects for neutron structure measurements with spectator tagging at EIC, the status of R&D efforts, and the accelerator and detector requirements.

Cosyn, W; Guzey, V; Higinbotham, D W; Hyde, C; Kuhn, S; Nadel-Turonski, P; Park, K; Sargsian, M; Strikman, M; Weiss, C

2014-10-27T23:59:59.000Z

64

Dr. Georg Ehlers - ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

65

Measurements of spin observables in pseudo-scalar meson photo-production using polarized neutrons in solid HD  

SciTech Connect (OSTI)

A measurement of psuedo-scalar meson photo production from longitudinally polarized solid HD has been carried out with the CLAS at Thomas Jefferson National Accelerator Facility (Jlab) with circularly and linearly polarized photon beams. Its aim is to measure a complete set of spin observables for the neutron simultaneously from the same experiment. As a polarized neutron, deutron in HD was used. Preliminary asymmetries are shown for the {pi}{sup -} channel.

Kageya, Tsuneo [JLAB, Newport News, VA (United States)

2014-01-01T23:59:59.000Z

66

On the Properties of Hypermassive Neutron Stars Formed in Mergers of Spinning Binaries  

E-Print Network [OSTI]

We present numerical simulations of binary neutron star (BNS) mergers, comparing irrotational binaries to binaries of NSs rotating aligned to the orbital angular momentum. For the first time, we study spinning BNSs employing nuclear physics equations of state (EOS), namely the ones of Lattimer & Swesty as well as Shen & Horowitz & Teige. We study mainly equal mass systems leading to a hypermassive neutron star (HMNS), and analyze in detail its structure and dynamics. In order to exclude gauge artifacts, we introduce a novel coordinate system used for post-processing. The results for our equal mass models show that the strong radial oscillations of the HMNS modulate the instantaneous frequency of the gravitational wave (GW) signal to an extend that leads to separate peaks in the corresponding Fourier spectrum. In particular, the high frequency peaks which are often attributed to combination frequencies can also be caused by the modulation of the m=2 mode frequency in the merger phase. As a consequence for GW data analysis, the offset of the high frequency peak does not necessarily carry information about the radial oscillation frequency. Further, the low frequency peak in our simulations is dominated by the contribution of the plunge and the first 1-2 bounces. The amplitude of the radial oscillations depends on the initial NS spin, which therefore has a complicated influence on the spectrum. Another important result is that HMNSs can consist of a slowly rotating core with an extended, massive envelope rotating close to Keplerian velocity, contrary to the common notion that a rapidly rotating core is necessary to prevent a prompt collapse. Finally, our estimates on the amount of unbound matter show a dependency on the initial NS spin, explained by the influence of the latter on the amplitude of radial oscillations, which in turn cause shock waves.

Wolfgang Kastaun; Filippo Galeazzi

2014-11-28T23:59:59.000Z

67

General relativistic simulations of black-hole-neutron-star mergers: Effects of black-hole spin  

SciTech Connect (OSTI)

Black-hole-neutron-star (BHNS) binary mergers are candidate engines for generating both short-hard gamma-ray bursts and detectable gravitational waves. Using our most recent conformal thin-sandwich BHNS initial data and our fully general relativistic hydrodynamics code, which is now adaptive mesh refinement capable, we are able to efficiently and accurately simulate these binaries from large separations through inspiral, merger, and ringdown. We evolve the metric using the Baumgarte-Shapiro-Shibata-Nakamura formulation with the standard moving puncture gauge conditions, and handle the hydrodynamics with a high-resolution shock-capturing scheme. We explore the effects of BH spin (aligned and antialigned with the orbital angular momentum) by evolving three sets of initial data with BH:NS mass ratio q=3: the data sets are nearly identical, except the BH spin is varied between a/M{sub BH}=-0.5 (antialigned), 0.0, and 0.75. The number of orbits before merger increases with a/M{sub BH}, as expected. We also study the nonspinning BH case in more detail, varying q between 1, 3, and 5. We calculate gravitational waveforms for the cases we simulate and compare them to binary black-hole waveforms. Only a small disk (<0.01M{sub {center_dot}}) forms for the antialigned spin case (a/M{sub BH}=-0.5) and for the most extreme-mass-ratio case (q=5). By contrast, a massive (M{sub disk}{approx_equal}0.2M{sub {center_dot}}) hot disk forms in the rapidly spinning (a/M{sub BH}=0.75) aligned BH case. Such a disk could drive a short-hard gamma-ray burst, possibly by, e.g., producing a copious flux of neutrino-antineutrino pairs.

Etienne, Zachariah B.; Liu, Yuk Tung; Shapiro, Stuart L. [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Baumgarte, Thomas W. [Department of Physics and Astronomy, Bowdoin College, Brunswick, Maine 04011 (United States)

2009-02-15T23:59:59.000Z

68

Implementing a search for aligned-spin neutron star -- black hole systems with advanced ground based gravitational wave detectors  

E-Print Network [OSTI]

We study the effect of spins on searches for gravitational waves from compact binary coalescences in realistic simulated early advanced LIGO data. We construct a detection pipeline including matched filtering, signal-based vetoes, a coincidence test between different detectors, and an estimate of the rate of background events. We restrict attention to neutron star--black hole (NS-BH) binary systems, and we compare a search using non-spinning templates to one using templates that include spins aligned with the orbital angular momentum. To run the searches we implement the binary inspiral matched-filter computation in PyCBC, a new software toolkit for gravitational-wave data analysis. We find that the inclusion of aligned-spin effects significantly increases the astrophysical reach of the search. Considering astrophysical NS-BH systems with non-precessing black hole spins, for dimensionless spin components along the orbital angular momentum uniformly distributed in $(-1, 1)$, the sensitive volume of the search with aligned-spin templates is increased by $\\sim 50\\%$ compared to the non-spinning search; for signals with aligned spins uniformly distributed in the range $(0.7,1)$, the increase in sensitive volume is a factor of $\\sim 10$.

Tito Dal Canton; Alexander H. Nitz; Andrew P. Lundgren; Alex B. Nielsen; Duncan A. Brown; Thomas Dent; Ian W. Harry; Badri Krishnan; Andrew J. Miller; Karl Wette; Karsten Wiesner; Joshua L. Willis

2014-10-27T23:59:59.000Z

69

Critical two- and three-spin correlations in EuS: An investigation with polarized neutrons  

SciTech Connect (OSTI)

The critical magnetic scattering has been investigated in EuS by means of small-angle scattering with polarized neutrons using an inclined magnetic field geometry, allowing the determination of three-spin correlation functions. Two contributions to the critical magnetic scattering I{sub {sigma}}(q)=I{sup {up_arrow}}(q)+I{sup {down_arrow}}(q) and {delta}I(q)=I{sup {up_arrow}}(q)-I{sup {down_arrow}}(q) were studied for temperatures near T{sub C}=16.52 K. The I{sup {up_arrow}}(q) and I{sup {down_arrow}}(q) are the scattering intensities for the incident neutron beam polarized along ({up_arrow}) and opposite ({down_arrow}) to the magnetic field. The symmetric contribution, namely I{sub {sigma}}(q), comes from the pair-spin correlation function. The scattering intensity is well described by the Ornstein-Zernike expression I{sub {sigma}}(q)=A(q{sup 2}+{kappa}{sup 2}){sup -1}, where {kappa}={xi}{sup -1} is the inverse correlation length of the critical fluctuations. The correlation length {xi} obeys the scaling law {xi}=a{sub 0}{tau}{sup -{nu}}, where {tau}=(T-T{sub C})/T{sub C} is the reduced temperature, a{sub 0}=0.17 nm, and {nu}=0.68{+-}0.01. The difference contribution {delta}I(q) is caused by the three-spin chiral dynamical spin fluctuations that represent the asymmetric part of the polarization dependent scattering. The q dependence of {delta}I(q) follows closely 1/q{sup 2}. {delta}I(q) depends on the temperature as {tau}{sup -{nu}} with {nu}=0.64{+-}0.05. The exponents {nu} as determined by means of the static measurements by {xi} and the dynamic measurements (using the chirality) are in excellent agreement with each other, demonstrating the internal consistency of the theory and the experiment. Therefore, our results confirm the principle of the critical factorization, which is known as Polyakov-Kadanoff-Wilson operator algebra.

Grigoriev, S.V.; Metelev, S.V.; Maleyev, S.V.; Okorokov, A.I. [Petersburg Nuclear Physics Institute, Gatchina, St. Petersburg 188300 (Russian Federation); Boeni, P.; Georgii, R.; Lamago, D. [TU-Munchen, Garching (Germany); Eckerlebe, H.; Pranzas, K. [GKSS Forschungszentrum, 21502 Geesthacht (Germany)

2005-12-01T23:59:59.000Z

70

Neutron scattering instrumentation at reactor based installations  

Science Journals Connector (OSTI)

During the past decade neutron scattering techniques have been applied to an increasingly wide range of scientific problems. Concurrently a number of substantial improvements of neutron scattering instrumentation have occurred to stimulate this trend. In this article several such developments which have occurred at reactor?based installations are described. Individual spectrometer components which are discussed in some detail include: neutron?optical devices such as guide tubes supermirrors and multilayer systems; neutronmonochromators with optimum reflectivity mosaic and focusing characteristics; position?sensitive detectors of several types; and equipment required for neutronpolarizationanalysis. Several novel spectrometers which have enhanced the role of neutron scattering during the past ten years are also described. These include spectrometers for small?angle scattering backscattering and neutron spin echo. An extensive bibliography is included which covers both early and more recent developments.

Roger Pynn

1984-01-01T23:59:59.000Z

71

High-spin structure and multiphonon {gamma} vibrations in very neutron-rich {sup 114}Ru  

SciTech Connect (OSTI)

High-spin levels of the neutron-rich {sup 114}Ru have been investigated by measuring the prompt {gamma} rays in the spontaneous fission of {sup 252}Cf. The ground-state band and one-phonon {gamma}-vibrational band have been extended up to 14{sup +} and 9{sup +}, respectively. Two levels are proposed as the members of a two-phonon {gamma}-vibrational band. A back bending (band crossing) has been observed in the ground-state band at ({h_bar}/2{pi}){omega}{approx_equal} 0.40 MeV. Using the triaxial deformation parameters, the cranked shell model calculations indicate that this back bending in {sup 114}Ru should originate from the alignment of a pair of h{sub 11/2} neutrons. Triaxial projected shell model calculations for the {gamma}-vibrational band structures of {sup 114}Ru are in good agreement with the experimental data. However, when using the oblate deformation parameters, both of the above-calculated results are not in agreement with the experimental data.

Yeoh, E. Y.; Wang, J. G.; Ding, H. B.; Gu, L.; Xu, Q.; Xiao, Z. G. [Department of Physics, Tsinghua University, Beijing 100084 (China); Zhu, S. J. [Department of Physics, Tsinghua University, Beijing 100084 (China); Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Hamilton, J. H.; Li, K.; Ramayya, A. V.; Hwang, J. K. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Liu, Y. X. [School of Science, Huzhou Teachers College, Huzhou 313000 (China); Liu, S. H. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); UNIRIB/Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831 (United States); Sun, Y. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Sheikh, J. A.; Bhat, G. H. [Department of Physics, University of Kashmir, Srinagar 190 006 (India); Luo, Y. X. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Rasmussen, J. O.; Lee, I. Y. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Ma, W. C. [Department of Physics, Mississippi State University, Mississippi State, Mississippi 39762 (United States)

2011-05-15T23:59:59.000Z

72

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

SciTech Connect (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

73

Neutron scattering studies of spin excitations in superconducting Rb0.82Fe1.68Se2  

SciTech Connect (OSTI)

We use inelastic neutron scattering to show that superconducting (SC) rubidium iron selenide Rb0.82Fe1.68Se2 exhibits antiferromagnetic (AF) spin excitations near the in-plane wave vector Q = ( ,0) identical to that for iron arsenide superconductors. Moreover, we find that these excitations change from incommensurate to commensurate with increasing energy and occur at the expense of spin waves associated with the coexisting 5 5 block AF phase. Since these spin excitations cannot come from Fermi surface nesting based on angle resolved photoemission experiments, our results indicate the presence of local moments in SC Rb0.82Fe1.68Se2 that may have a similar origin as the hourglass-like spin excitations in copper oxide superconductors.

Wang, Miaoyin [University of Tennessee, Knoxville (UTK); Li, Chunhong [The Institute of Physics, Chinese Academy of Sciences; Abernathy, Douglas L [ORNL; Song, Yu [University of Tennessee, Knoxville (UTK); Carr, Scott V. [University of Tennessee, Knoxville (UTK); Lu, Xiangye [The Institute of Physics, Chinese Academy of Sciences; Li, Shiliang [The Institute of Physics, Chinese Academy of Sciences; Yamari, Zahra [Canadian Neutron Beam Centre, National Research Council, Chalk River Laboratorie; Hu, Jiangping [Purdue University and Chinese Academy of Sciences; Xiang, Tao [The Institute of Physics, Chinese Academy of Sciences; Dai, Pengcheng [University of Tennessee, Knoxville (UTK)

2012-01-01T23:59:59.000Z

74

Absence of spin-flip transition at the Cr(001) surface: A combined spin-polarized scanning tunneling microscopy and neutron scattering study  

SciTech Connect (OSTI)

The spin-density wave (SDW) on Cr(001) has been investigated at temperatures between 20-300 K by means of spin-polarized scanning tunneling microscopy (SP-STM). Although neutron-scattering data measured on the same crystal clearly show a spin-flip transition from a transversal (T)-SDW to a longitudinal (L)-SDW at the expected spin-flip (SF) temperature T{sub SF}=123 K, no change was found on the Cr(001) surface with SP-STM. Throughout the entire temperature range the Cr(001) surface maintains a topological antiferromagnetic order with an in-plane magnetization that inverts between adjacent atomically flat terraces separated by monatomic step edges. The experimental results are interpreted by an absence of a spin-flip transition in the near-surface region probably driven by the surface anisotropy. The continuous connection of the surface T-SDW to the bulk L-SDW is accomplished by the formation of a 90 deg. domain wall just below the surface.

Haenke, T.; Krause, S.; Berbil-Bautista, L.; Bode, M.; Wiesendanger, R.; Wagner, V.; Lott, D.; Schreyer, A. [Institute of Applied Physics and Microstructure Research Center, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg (Germany); Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-38116 Braunschweig (Germany); Institut fuer Werkstoffforschung, GKSS Forschungszentrum, Max-Planck-Strasse 1, D-21502 Geesthacht (Germany)

2005-05-01T23:59:59.000Z

75

SNS Instrument System Beam Lines | ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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)

76

Sample Environment Equipment Categories - ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

77

Spin exchange optical pumping based polarized {sup 3}He filling station for the Hybrid Spectrometer at the Spallation Neutron Source  

SciTech Connect (OSTI)

The Hybrid Spectrometer (HYSPEC) is a new direct geometry spectrometer at the Spallation Neutron Source at the Oak Ridge National Laboratory. This instrument is equipped with polarization analysis capability with 60 Degree-Sign horizontal and 15 Degree-Sign vertical detector coverages. In order to provide wide angle polarization analysis for this instrument, we have designed and built a novel polarized {sup 3}He filling station based on the spin exchange optical pumping method. It is designed to supply polarized {sup 3}He gas to HYSPEC as a neutron polarization analyzer. In addition, the station can optimize the {sup 3}He pressure with respect to the scattered neutron energies. The depolarized {sup 3}He gas in the analyzer can be transferred back to the station to be repolarized. We have constructed the prototype filling station. Preliminary tests have been carried out demonstrating the feasibility of the filling station. Here, we report on the design, construction, and the preliminary results of the prototype filling station.

Jiang, C. Y.; Tong, X.; Brown, D. R.; Culbertson, H.; Kadron, B.; Robertson, J. L. [Instrument and Source Design Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Graves-Brook, M. K. [Research Accelerator Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Hagen, M. E. [Neutron Data Analysis and Visualization Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Lee, W. T. [Australian Nuclear Science and Technology Organisation, New Illawarra Road, Lucas Heights, NSW 2234 (Australia); Winn, B. [Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2013-06-15T23:59:59.000Z

78

MAGNETIC NEUTRON SCATTERING  

SciTech Connect (OSTI)

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

79

A polarized neutron reflectometry study of the spin glass freezing in a 29nm thick AuFe film  

Science Journals Connector (OSTI)

We performed polarized neutron reflectometry (PNR) experiments on a 29nm thick Au93Fe7 film in a temperature range from 295K down to 2K in a vertical magnetic field up to 6T. These high-field experiments were performed on the C5 spectrometer in Chalk River, Canada, using a split-pair cryomagnet. The magnetization as determined by PNR can be described with a Brillouin function from 295K down to 50K assuming the magnetic moment of isolated Fe atoms, i.e. 4 ? B per Fe atom. Below 50K the onset of the spin-glass freezing is observed as a strong deviation from this Brillouin type behavior of isolated atoms.

H. Fritzsche; M. Saoudi; K. Temst; C. Van Haesendonck

2007-01-01T23:59:59.000Z

80

The Science of NSE | ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

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81

Size Effect in the Spin Glass Magnetization of Thin AuFe Films as Studied by Polarized Neutron Reflectometry  

Science Journals Connector (OSTI)

We used polarized neutron reflectometry to determine the temperature dependence of the magnetization of thin AuFe films with 3% Fe concentration. We performed the measurements in a large magnetic field of 6T in a temperature range from 295 to 2K. For the films in the thickness range from 500 to 20nm we observed a Brillouin-type behavior from 295K down to 50K and a constant magnetization of about 0.9?B per Fe atom below 30K. However, for the 10nm thick film we observed a Brillouin-type behavior down to 20K and a constant magnetization of about 1.3?B per Fe atom below 20K. These experiments are the first to show a finite-size effect in the magnetization of single spin-glass films in large magnetic fields. Furthermore, the ability to measure the deviation from the paramagnetic behavior enables us to prove the existence of the spin-glass state where other methods relying on a cusp-type behavior fail.

M. Saoudi; H. Fritzsche; G. J. Nieuwenhuys; M. B. S. Hesselberth

2008-02-06T23:59:59.000Z

82

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

SciTech Connect (OSTI)

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

83

Echoes and Revival Echoes in Systems of Anharmonically Confined Atoms  

E-Print Network [OSTI]

We study echoes and what we call 'revival echoes' for a collection of atoms that are described by a single quantum wavefunction and are confined in a weakly anharmonic trap. The echoes and revival echoes are induced by applying two, successive temporally localized potential perturbations to the confining potential, one at time $t=0$, and a smaller one at time $t=\\tau$. Pulse-like responses in the expectation value of position $$ are predicted at $t \\approx n\\tau$ ($n=2,3,...$) and are particularly evident at $t = 2\\tau$. A novel result of our study is the finding of 'revival echoes'. Revivals (but not echoes) occur even if the second perturbation is absent. In particular, in the absence of the second perturbation, the response to the first perturbation dies away, but then reassembles, producing a response at revival times $mT_x$ ($m=1,2,...$). Including the second perturbation at $t=\\tau$, we find temporally localized responses, revival echoes, both before and after $t\\approx mT_x$, e.g., at $t\\approx m T_x-n...

Herrera, Mark; Ott, Edward; Fishman, Shmuel

2012-01-01T23:59:59.000Z

84

Thermodynamic and neutron scattering study of the spin- 1/2 kagome antiferromagnet ZnCu?(OH)?Cl? : a quantum spin liquid system  

E-Print Network [OSTI]

New physics, such as a quantum spin liquid, can emerge in systems where quantum fluctuations are enhanced due to reduced dimensionality and strong frustration. The realization of a quantum spin liquid in two-dimensions ...

Han, Tianheng, Ph. D. Massachusetts Institute of Technology

2012-01-01T23:59:59.000Z

85

Spin-aligned neutron-proton pairs in N=Z nuclei  

SciTech Connect (OSTI)

A study is carried out on the role of the aligned neutron-proton pair with angular momentum J=9 and isospin T=0 in the low-energy spectroscopy of the N=Z nuclei {sup 96}Cd, {sup 94}Ag, and {sup 92}Pd. Shell-model wave functions resulting from realistic interactions are analyzed in terms of a variety of two-nucleon pairs corresponding to different choices of their coupled angular momentum J and isospin T. The analysis is performed exactly for four holes ({sup 96}Cd) and carried further for six and eight holes ({sup 94}Ag and {sup 92}Pd) by means of a mapping to an appropriate version of the interacting boson model. The study allows the identification of the strengths and deficiencies of the aligned-pair approximation.

Zerguine, S. [Department of Physics, PRIMALAB Laboratory, University of Batna, Avenue Boukhelouf M El Hadi, 05000 Batna (Algeria); Van Isacker, P. [Grand Accelerateur National d'Ions Lourds, CEA/DSM-CNRS/IN2P3, B.P. 55027, F-14076 Caen Cedex 5 (France)

2011-06-15T23:59:59.000Z

86

Large-scale shell-model calculations for unnatural-parity high-spin states in neutron-rich Cr and Fe isotopes  

E-Print Network [OSTI]

We investigate unnatural-parity high-spin states in neutron-rich Cr and Fe isotopes using large-scale shell-model calculations. These shell-model calculations are carried out within the model space of $fp$-shell + $0g_{9/2}$ + $1d_{5/2}$ orbits with the truncation allowing $1\\hbar\\omega$ excitation of a neutron. The effective Hamiltonian consists of GXPF1Br for $fp$-shell orbits and $V_{\\rm MU}$ with a modification for the other parts. The present shell-model calculations can describe and predict the energy levels of both natural- and unnatural-parity states up to the high-spin states in Cr and Fe isotopes with $N\\le35$. The total energy surfaces present the prolate deformations on the whole and indicate that the excitation of one neutron into the $0g_{9/2}$ orbit plays the role of enhancing the prolate deformation. For the positive(unnatural)-parity states in odd-mass Cr and Fe isotopes, their energy levels and prolate deformations indicate the decoupling limit of the particle-plus-rotor model. We have found...

Togashi, Tomoaki; Utsuno, Yutaka; Otsuka, Takaharu; Honma, Michio

2014-01-01T23:59:59.000Z

87

Commissioning the Echo-Seeding Experiment Echo-7 at SLAC  

SciTech Connect (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

88

Dr. Ferenc Mezei, Los Alamos National Laboratory, Los Alamos, NM  

ScienceCinema (OSTI)

Neutron Spin Echo Spectroscopy: History and Outlook. Presented at the Workshop on Spin Echo Spectroscopy 2009 at Oak Ridge National Laboratory on November 4, 2009.

Dr. Ferenc Mezei

2010-01-08T23:59:59.000Z

89

Anisotropic inplane spin correlation in the parent and Co-doped BaFe2As2: A neutron scattering study  

Science Journals Connector (OSTI)

Abstract Antiferromagnetic spin fluctuations were investigated in the normal states of the parent (x=0), under-doped (x=0.04) and optimally-doped (x=0.06) Ba ( Fe 1 - x Co x ) 2 As 2 single crystals using inelastic neutron scattering technique. For all the doping levels, quasi-two-dimensional antiferromagnetic fluctuations were observed as a broad peak localized at Q = ( 1 / 2 , 1 / 2 , l ) . At lower energies, the peak shows an apparent anisotropy in the h k 0 plane; longitudinal peak widths are considerably smaller than transverse widths. The anisotropy is larger for the higher doping level. These results are consistent with the random phase approximation (RPA) calculations taking account of the orbital character of the electronic bands, confirming that the anisotropic nature of the spin fluctuations in the normal states is mostly dominated by the nesting of Fermi surfaces. On the other hand, the quasi-two-dimensional spin correlations grow much rapidly for decreasing temperature in the x=0 parent compound, compared to that expected for nearly antiferromagnetic metals. This may be another sign of the unconventional nature of the antiferromagnetic transition in BaFe2As2.

S. Ibuka; Y. Nambu; T. Yamazaki; M.D. Lumsden; T.J. Sato

2014-01-01T23:59:59.000Z

90

Echo-Enabled Harmonic Generation  

SciTech Connect (OSTI)

A recently proposed concept of the Echo-Enabled Harmonic Generation (EEHG) FEL uses two laser modulators in combination with two dispersion sections to generate a high-harmonic density modulation in a relativistic beam. This seeding technique holds promise of a one-stage soft x-ray FEL that radiates not only transversely but also longitudinally coherent pulses. Currently, an experimental verification of the concept is being conducted at the SLAC National Accelerator Laboratory aimed at the demonstration of the EEHG.

Stupakov, Gennady

2010-08-25T23:59:59.000Z

91

Echo-Enabled Harmonic Generation  

SciTech Connect (OSTI)

A recently proposed concept of the Echo-Enabled Harmonic Generation (EEHG) FEL uses two laser modulators in combination with two dispersion sections to generate a high-harmonic density modulation in a relativistic beam. This seeding technique holds promise of a one-stage soft x-ray FEL that radiates not only transversely but also longitudinally coherent pulses. Currently, an experimental verification of the concept is being conducted at the SLAC National Accelerator Laboratory aimed at the demonstration of the EEHG.

Stupakov, Gennady; /SLAC

2012-06-28T23:59:59.000Z

92

Excess wing in glass-forming glycerol and LiCl-glycerol mixtures detected by neutron scattering  

E-Print Network [OSTI]

The relaxational dynamics in glass-forming glycerol and glycerol mixed with LiCl is in-vestigated using different neutron scattering techniques. The performed neutron spin-echo experiments, which extend up to relatively long relaxation-time scales of the order of 10 ns, should allow for the detection of contributions from the so-called excess wing. This phenomenon, whose microscopic origin is controversially discussed, arises in a variety of glass formers and, until now, was almost exclusively investigated by dielectric spectros-copy and light scattering. Here we show that the relaxational process causing the excess wing also can be detected by neutron scattering, which directly couples to density fluctua-tions.

S. Gupta; N. Arend; P. Lunkenheimer; A. Loidl; L. Stingaciu; N. Jalarvo; E. Mamontov; M. Ohl

2014-03-08T23:59:59.000Z

93

Photo Echo and Optical Nutation in Molecules  

Science Journals Connector (OSTI)

Photon echo and optical nutation have been easily observed in C13H3F and NH2D by applying Stark pulses which shift the molecular levels into resonance with cw laser radiation. Numerical computations of the nutation effect agree with observation, and echo characteristics closely follow predictions of existing theories. The T2? pressure dependence, from infrared-echo measurements, indicates that C13H3F relaxes primarily by rotational energy transfer.

Richard G. Brewer and R. L. Shoemaker

1971-09-06T23:59:59.000Z

94

E-Print Network 3.0 - advanced neutron beam Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

level Summary: . Neutrons have SPIN. They can be formed into polarized neutron beams, used to study nuclear (atomic... Spallation Neutron Source (SNS) The world's most...

95

Partial Spin Ordering and Complex Magnetic Structure in BaYFeO4: A Neutron Diffraction and High Temperature Susceptibility Study  

SciTech Connect (OSTI)

The novel iron-based compound, BaYFeO4, crystallizes in the Pnma space group with two distinct Fe3+ sites, that are alternately corner-shared [FeO5]7 square pyramids and [FeO6]9 octahedra, forming into [Fe4O18]24 rings, which propagate as columns along the b-axis. A recent report shows two discernible antiferromagnetic (AFM) transitions at 36 and 48 K in the susceptibility, yet heat capacity measurements reveal no magnetic phase transitions at these temperatures. An upturn in the magnetic susceptibility measurements up to 400 K suggests the presence of shortrange magnetic behavior at higher temperatures. In this Article, variable-temperature neutron powder diffraction and hightemperature magnetic susceptibility measurements were performed to clarify the magnetic behavior. Neutron powder diffraction confirmed that the two magnetic transitions observed at 36 and 48 K are due to long-range magnetic order. Below 48 K, the magnetic structure was determined as a spin-density wave (SDW) with a propagation vector, k = (0, 0, 1/3), and the moments along the b-axis, whereas the structure becomes an incommensurate cycloid [k = (0, 0, 0.35)] below 36 K with the moments within the bc-plane. However, for both cases the ordered moments on Fe3+ are only of the order 3.0 B, smaller than the expected values near 4.5 B, indicating that significant components of the Fe moments remain paramagnetic to the lowest temperature studied, 6 K. Moreover, new high-temperature magnetic susceptibility measurements revealed a peak maximum at 550 K indicative of short-range spin correlations. It is postulated that most of the magnetic entropy is thus removed at high temperatures which could explain the absence of heat capacity anomalies at the long-range ordering temperatures. Published spin dimer calculations, which appear to suggest a k = (0, 0, 0) magnetic structure, and allow for neither low dimensionality nor geometric frustration, are inadequate to explain the observed complex magnetic structure.

Thompson, Corey [Florida State University, Tallahassee] [Florida State University, Tallahassee; Greedan, John [McMaster University] [McMaster University; Garlea, Vasile O [ORNL] [ORNL; Flacau, Roxana [National Research Council of Canada] [National Research Council of Canada; Tan, Malinda [California State University, Long Beach (CSULB)] [California State University, Long Beach (CSULB); Derakhshan, Shahab [California State University, Long Beach (CSULB)] [California State University, Long Beach (CSULB)

2014-01-01T23:59:59.000Z

96

Observing proton motion on the nanoscale in polymeric electrolyte membranes with quasielastic neutron scattering  

Science Journals Connector (OSTI)

Abstract The mechanism of proton conductivity in high temperature polymer electrolyte fuel cells (HT-PEFCs) has been investigated with macroscopic conductivity measurements and on a microscopic scale with quasielastic neutron scattering techniques. Polybenzimidazole membranes, which are used in HT-PEFCs, are doped with phosphoric acid (PA) to achieve the desired proton conductivity. Neutron spin echo experiments showed that the polymer matrix is very rigid incoherent scattering experiments, but incoherent scattering revealed rather fast diffusion processes, compatible with macroscopic conductivity measurements. The measured diffusion is faster than anticipated from the conductivity of a phosphoric acid doped PBI membrane, but slower than that expected for pure phosphoric acid. Over larger distances the fractal polymer membrane network slows down the locally fast diffusion to the macroscopic values. With elastic fixed window scans on a backscattering spectrometer an activation energy of 7.6kJ/mol is obtained at typical conditions in an HT-PEFC.

O. Holderer; O. Ivanova; B. Hopfenmller; M. Zamponi; W. Maier; A. Majerus; W. Lehnert; M. Monkenbusch; R. Zorn

2014-01-01T23:59:59.000Z

97

DIFFUSION INELASTIQUE DES AIEUTRONS ET ONDES DE SPIN  

E-Print Network [OSTI]

measured in the three principal symmetry directions by neutron inelastic scattering.The spin wave of neutrons C(Eogo)scattered by a spin wave of energy Eo and wave vector qo satisfies the following diffusion inklastiquedes neutrons. On a trouvB que les relations de dispersion des ondes de spin

Boyer, Edmond

98

EChO - Exoplanet Characterisation Observatory  

E-Print Network [OSTI]

A dedicated mission to investigate exoplanetary atmospheres represents a major milestone in our quest to understand our place in the universe by placing our Solar System in context and by addressing the suitability of planets for the presence of life. EChO -the Exoplanet Characterisation Observatory- is a mission concept specifically geared for this purpose. EChO will provide simultaneous, multi-wavelength spectroscopic observations on a stable platform that will allow very long exposures. EChO will build on observations by Hubble, Spitzer and groundbased telescopes, which discovered the first molecules and atoms in exoplanetary atmospheres. EChO will simultaneously observe a broad enough spectral region -from the visible to the mid-IR- to constrain from one single spectrum the temperature structure of the atmosphere and the abundances of the major molecular species. The spectral range and resolution are tailored to separate bands belonging to up to 30 molecules to retrieve the composition and temperature str...

Tinetti, G; Henning, T; Meyer, M; Micela, G; Ribas, I; Stam, D; Swain, M; Krause, O; Ollivier, M; Pace, E; Swinyard, B; Aylward, A; van Boekel, R; Coradini, A; Encrenaz, T; Snellen, I; Zapatero-Osorio, M R; Bouwman, J; Cho, J Y-K; Foresto, V Coud du; Guillot, T; Lopez-Morales, M; Mueller-Wodarg, I; Palle, E; Selsis, F; Sozzetti, A; Ade, P A R; Achilleos, N; Adriani, A; Agnor, C B; Afonso, C; Prieto, C Allende; Bakos, G; Barber, R J; Barlow, M; Bernath, P; Bezard, B; Bord, P; Brown, L R; Cassan, A; Cavarroc, C; Ciaravella, A; Cockell, C O U; Coustenis, A; Danielski, C; Decin, L; De Kok, R; Demangeon, O; Deroo, P; Doel, P; Drossart, P; Fletcher, L N; Focardi, M; Forget, F; Fossey, S; Fouqu, P; Frith, J; Galand, M; Gaulme, P; Hernndez, J I Gonzlez; Grasset, O; Grassi, D; Grenfell, J L; Griffin, M J; Griffith, C A; Grzinger, U; Guedel, M; Guio, P; Hainaut, O; Hargreaves, R; Hauschildt, P H; Heng, K; Heyrovsky, D; Hueso, R; Irwin, P; Kaltenegger, L; Kervella, P; Kipping, D; Koskinen, T T; Kovcs, G; La Barbera, A; Lammer, H; Lellouch, E; Leto, G; Morales, M Lopez; Valverde, M A Lopez; Lopez-Puertas, M; Lovis, C; Maggio, A; Maillard, J P; Prado, J Maldonado; Marquette, J B; Martin-Torres, F J; Maxted, P; Miller, S; Molinari, S; Montes, D; Moro-Martin, A; Moses, J I; Mousis, O; Tuong, N Nguyen; Nelson, R; Orton, G S; Pantin, E; Pascale, E; Pezzuto, S; Pinfield, D; Poretti, E; Prinja, R; Prisinzano, L; Rees, J M; Reiners, A; Samuel, B; Sanchez-Lavega, A; Forcada, J Sanz; Sasselov, D; Savini, G; Sicardy, B; Smith, A; Stixrude, L; Strazzulla, G; Tennyson, J; Tessenyi, M; Vasisht, G; Vinatier, S; Viti, S; Waldmann, I; White, G J; Widemann, T; Wordsworth, R; Yelle, R; Yung, Y; Yurchenko, S N

2011-01-01T23:59:59.000Z

99

Asymmetric radar echo patterns from insects.  

Science Journals Connector (OSTI)

Radar echoes from insects, birds, and bats in the atmosphere exhibit both symmetry and asymmetry in polarimetric patterns. Symmetry refers to similar magnitudes of polarimetric variables at opposite azimuths, and asymmetry relegates to differences ...

Valery M. Melnikov; Michael J. Istok; John K. Westbroo

100

A study of diffusion in binary solutions using spin echoes  

E-Print Network [OSTI]

Acetone 21 ~ 25 26 27 5 The Concentration Dependence of the Diffusion Coefficient of' Benzene in C6H6-CC1~ Solution Intrinsic 29 The Concentration Dependence of the Diffusion Coefficient of Benzene in C6H6-CS2 Solution Intrinsic a 30 ~ ~ 32... The Concentration Dependence of the Intrinsic Diffusion Coefficient of Cyclohexane in a C6H12 CC1~ Solution The Concentration Dependence of the Intrinsic Diffusion Coefficient of Cyclohexane in a C6H12-CS2 Solution LIST C1" TABLES Table Page Comparison...

Rousseau, Cecil Clyde

2012-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "neutron spin echo" from the National Library of EnergyBeta (NLEBeta).
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101

Ramsey Experiments Using Neutron Beams  

Science Journals Connector (OSTI)

Abstract Ramsey's technique of separated oscillatory fields adapted to cold neutron beams is a very sensitive method to probe for spin- dependent interactions of neutrons with magnetic and pseudomagnetic fields. In the last couple of years several distinctive experiments using this technique have been performed, e.g. to determine the incoherent neutron scattering length of the deuteron, to perform polarized neutron imaging of magnetic fields and samples, and lately, to search for new light spin-1 bosons. Here, some of these results are reviewed and possible future measurements with respect to a pulsed neutron source are presented.

Florian M. Piegsa

2014-01-01T23:59:59.000Z

102

Decoherence from spin environments  

Science Journals Connector (OSTI)

We examine two exactly solvable models of decoherencea central spin-system, (i) with and (ii) without a self-Hamiltonian, interacting with a collection of environment spins. In the absence of a self-Hamiltonian we show that in this model (introduced some time ago to illustrate environment-induced superselection) generic assumptions about the coupling strengths can lead to a universal (Gaussian) suppression of coherence between pointer states. On the other hand, we show that when the dynamics of the central spin is dominant a different regime emerges, which is characterized by a non-Gaussian decay and a dramatically different set of pointer states. We explore the regimes of validity of the Gaussian decay and discuss its relation to the spectral features of the environment and to the Loschmidt echo (or fidelity).

F. M. Cucchietti; J. P. Paz; W. H. Zurek

2005-11-29T23:59:59.000Z

103

Los Alamos director echoes cyber concerns  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

104

Quantum correlations in a noisy neutron interferometer  

E-Print Network [OSTI]

We investigate quantum coherences in the presence of noise by entangling the spin and path degrees of freedom of the output neutron beam from a noisy three-blade perfect crystal neutron interferometer. We find that in the ...

Wood, Christopher J.

105

Accumulated photon echo in ruby and alexandrite  

Science Journals Connector (OSTI)

The technique of picosecond accumulated photon echo is applied to 700-at. ppm ruby and 2000-at. ppm alexandrite. The decay of the photon-echo intensity versus the probe-pulse delay displays a beat. A detailed analysis on the basis of Bloch equations shows that the beat frequency is associated with the zero-field splitting of the 4A2 ground state, and that its phase and amplitude are determined by the amount of population communication within this state. Precise values for the spontaneous decay time of 2A(2E) and the 4A2 zero-field splitting are derived.

M. H. F. Overwijk; P. J. Rump; J. I. Dijkhuis; H. W. de Wijn

1991-09-01T23:59:59.000Z

106

The echo response inGnathonemus petersii (Mormyridae)  

Science Journals Connector (OSTI)

Gnathonemus petersii...respond to each other's electric organ discharge (EOD) with an echo discharge of their...

C. J. Russell; J. P. Myers; C. C. Bell

1974-01-01T23:59:59.000Z

107

Inelastic Neutron Scattering Study of a Nonmagnetic Collapsed Tetragonal Phase in Nonsuperconducting CaFe2As2: Evidence of the Impact of Spin Fluctuations on Superconductivity in the Iron-Arsenide Compounds  

SciTech Connect (OSTI)

The relationship between antiferromagnetic spin fluctuations and superconductivity has become a central topic of research in studies of superconductivity in the iron pnictides. We present unambiguous evidence of the absence of magnetic fluctuations in the nonsuperconducting collapsed tetragonal phase of CaFe2As2 via inelastic neutron scattering time-of-flight data, which is consistent with the view that spin fluctuations are a necessary ingredient for unconventional superconductivity in the iron pnictides. We demonstrate that the collapsed tetragonal phase of CaFe2As2 is nonmagnetic, and discuss this result in light of recent reports of high-temperature superconductivity in the collapsed tetragonal phase of closely related compounds.

Soh, Jing-Han [Ames Laboratory; Tucker, Ggregory S. [Ames Laboratory; Pratt, Daniel K. [Ames Laboratory; Abernathy, D. L. [Oak Ridge National Laboratory; Stone, M. B. [Oak Ridge National Laboratory; Ran, Sheng [Ames Laboratory; Budko, Sergey L. [Ames Laboratory; Canfield, Paul C. [Ames Laboratory; Kreyssig, Andreas [Ames Laboratory; McQueeney, Robert J. [Ames Laboratory; Goldman, Alan I. [Ames Laboratory

2013-11-27T23:59:59.000Z

108

Inelastic neutron scattering study of a nonmagnetic collapsed tetragonal phase of CaFe2As2: Evidence of the impact of spin fluctuations on superconductivity in the iron-arsenide compounds.  

SciTech Connect (OSTI)

The relationship between antiferromagnetic spin fluctuations and superconductivity has become a central topic of research in studies of superconductivity in the iron pnictides. We present unambiguous evidence of the absence of magnetic fluctuations in the non-superconducting collapsed tetragonal phase of CaFe2As2 via inelas- tic neutron scattering time-of-flight data, which is consistent with the view that spin fluctuations are a necessary ingredient for unconventional superconductivity in the iron pnictides. We demonstrate that the collapsed tetrag- onal phase of CaFe2As2 is non-magnetic, and discuss this result in light of recent reports of high-temperature superconductivity in the collapsed tetragonal phase of closely related compounds.

Soh, Jing Han [ORNL] [ORNL; Tucker, G. S. [Ames Laboratory and Iowa State University] [Ames Laboratory and Iowa State University; Pratt, Daniel K [ORNL] [ORNL; Abernathy, Douglas L [ORNL] [ORNL; Stone, Matthew B [ORNL] [ORNL; Ran, S. [Ames Laboratory and Iowa State University] [Ames Laboratory and Iowa State University; Budko, S L [Ames Laboratory and Iowa State University] [Ames Laboratory and Iowa State University; Canfield, P. C. [Ames Laboratory] [Ames Laboratory; Kreyssig, A. [Ames Laboratory and Iowa State University] [Ames Laboratory and Iowa State University; McQueeney, R. J. [Ames Laboratory] [Ames Laboratory; Goldman, A. I. [Ames Laboratory and Iowa State University] [Ames Laboratory and Iowa State University

2013-01-01T23:59:59.000Z

109

Neutron-Spin Resonance in the Optimally Electron-Doped Superconductor Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4-{delta}}  

SciTech Connect (OSTI)

We use inelastic neutron scattering to probe magnetic excitations of an optimally electron-doped superconductor Nd{sub 1.85}Ce{sub 0.15}CuO{sub 4-{delta}} above and below its superconducting transition temperature T{sub c}=25 K. In addition to gradually opening a spin pseudogap at the antiferromagnetic ordering wave vector Q=(1/2,1/2,0), the effect of superconductivity is to form a resonance centered also at Q=(1/2,1/2,0) but at energies above the spin pseudogap. The intensity of the resonance develops like a superconducting order parameter, similar to those for hole-doped superconductors and electron-doped Pr{sub 0.88}LaCe{sub 0.12}CuO{sub 4}. The resonance is therefore a general phenomenon of cuprate superconductors, and must be fundamental to the mechanism of high-T{sub c} superconductivity.

Zhao Jun; Li Shiliang [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996-1200 (United States); Dai Pengcheng [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996-1200 (United States); Neutron Scattering Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393 (United States); Freeman, Paul G. [Institut Laue-Langevin, 6, rue Jules Horowitz, BP156-38042 Grenoble Cedex 9 (France); Onose, Y. [Spin Superstructure Project, ERATO, Japan Science and Technology, Tsukuba 305-8562 (Japan); Tokura, Y. [Spin Superstructure Project, ERATO, Japan Science and Technology, Tsukuba 305-8562 (Japan); Department of Applied Physics, University of Tokyo, Tokyo 13-8656 (Japan)

2007-07-06T23:59:59.000Z

110

E-Print Network 3.0 - active neutron correlation Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Sample search results for: active neutron correlation Page: << < 1 2 3 4 5 > >> 1 The Neutron Scattering Society www.neutronscattering.org Summary: of antiferromagnetic spin...

111

Ultrasonic unipolar pulse/echo instrument  

DOE Patents [OSTI]

An ultrasonic unipolar pulse/echo instrument uses active switches and a timing and drive circuitry to control electrical energy to a transducer, the discharging of the transducer, and the opening of an electrical pathway to the receiving circuitry for the returning echoes. The active switches utilize MOSFET devices along with decoupling circuitry to insure the preservation of the unipolar nature of the pulses, insure fast transition times, and maintain broad band width and time resolution. A housing contains the various circuitry and switches and allows connection to a power supply and a movable ultrasonic transducer. The circuitry maintains low impedance input to the transducer during transmitting cycles, and high impedance between the transducer and the receiving circuit during receive cycles to maintain the unipolar pulse shape. A unipolar pulse is valuable for nondestructive evaluation, a prime use for the present instrument.

Hughes, M.J.; Hsu, D.K.; Thompson, D.O.; Wormley, S.J.

1993-04-06T23:59:59.000Z

112

The ground state of the spin-1/2 kagom lattice antiferromagnet : neutron scattering studies of the zinc-paratacamite mineral family  

E-Print Network [OSTI]

The magnetic properties of the geometrically frustrated quantum magnets clinoatacamite, Cu2(OH)3Cl, and herbertsmithite, ZnCu3(OH)6Cl2, are studied by means of neutron scattering measurements as well as specific heat, ...

Helton, Joel Strader

2009-01-01T23:59:59.000Z

113

Liquid 1-propanol studied by neutron scattering, near-infrared, and dielectric spectroscopy  

SciTech Connect (OSTI)

Liquid monohydroxy alcohols exhibit unusual dynamics related to their hydrogen bonding induced structures. The connection between structure and dynamics is studied for liquid 1-propanol using quasi-elastic neutron scattering, combining time-of-flight and neutron spin-echo techniques, with a focus on the dynamics at length scales corresponding to the main peak and the pre-peak of the structure factor. At the main peak, the structural relaxation times are probed. These correspond well to mechanical relaxation times calculated from literature data. At the pre-peak, corresponding to length scales related to H-bonded structures, the relaxation times are almost an order of magnitude longer. According to previous work [C. Gainaru, R. Meier, S. Schildmann, C. Lederle, W. Hiller, E. Rssler, and R. Bhmer, Phys. Rev. Lett. 105, 258303 (2010)] this time scale difference is connected to the average size of H-bonded clusters. The relation between the relaxation times from neutron scattering and those determined from dielectric spectroscopy is discussed on the basis of broad-band permittivity data of 1-propanol. Moreover, in 1-propanol the dielectric relaxation strength as well as the near-infrared absorbance reveal anomalous behavior below ambient temperature. A corresponding feature could not be found in the polyalcohols propylene glycol and glycerol.

Sillrn, P.; Matic, A.; Karlsson, M. [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Gteborg (Sweden)] [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Gteborg (Sweden); Koza, M.; Maccarini, M.; Fouquet, P. [Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9 (France)] [Institut Laue Langevin, 6, rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9 (France); Gtz, M.; Bauer, Th.; Gulich, R.; Lunkenheimer, P.; Loidl, A. [Experimental Physics V, University of Augsburg, 86135 Augsburg (Germany)] [Experimental Physics V, University of Augsburg, 86135 Augsburg (Germany); Mattsson, J. [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom)] [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Gainaru, C.; Vynokur, E.; Schildmann, S.; Bauer, S.; Bhmer, R. [Fakultt fr Physik, Technische Universitt Dortmund, 44221 Dortmund (Germany)] [Fakultt fr Physik, Technische Universitt Dortmund, 44221 Dortmund (Germany)

2014-03-28T23:59:59.000Z

114

More about neutron - mirror neutron oscillation  

E-Print Network [OSTI]

It was pointed out recently that oscillation of the neutron $n$ into mirror neutron $n'$, a sterile twin of the neutron with exactly the same mass, could be a very fast process with the the baryon number violation, even faster than the neutron decay itself. This process is sensitive to the magnetic fields and it could be observed by comparing the neutron lose rates in the UCN storage chambers for different magnetic backgrounds. We calculate the probability of $n-n'$ oscillation in the case when a mirror magnetic field $\\vec{B}'$ is non-zero and show that in this case it can be suppressed or resonantly enhanced by applying the ordinary magnetic field $\\vec{B}$, depending on its strength and on its orientation with respect to $\\vec{B}'$. The recent experimental data, under this hypothesis, still allow the $n-n'$ oscillation time order 1 s or even smaller. Moreover, they indicate that the neutron losses are sensitive to the orientation of the magnetic field. %at about $3\\sigma$ level. If these hints will be confirmed in the future experiments, this would point to the presence of the mirror magnetic field on the Earth of the order of 0.1 G, or some equivalent spin-dependent force of the other origin that makes a difference between the neutron and mirror neutron states.

Zurab Berezhiani

2008-04-13T23:59:59.000Z

115

Neutron skin of nuclei near the neutron drip line  

Science Journals Connector (OSTI)

Performing Skyrme-type deformed Hartree-Fock calculations, the possible presence of neutron skin in nuclei towards neutron drip line is studied. The thickness of the neutron skin is found to be nearly constant in all directions if it is measured perpendicular to the surface, and in a given nucleus the number of neutrons being inside of the neutron skin is almost independent of the deformation (namely, spherical shape or normal deformation or superdeformation). In the region of medium-heavy nuclei our calculation shows the presence of a series of neutron-rich nuclei, in which a neutron skin is present and yet the neutron one-particle spectra are far from those in a harmonic oscillator (plus spin-orbit) potential.

I. Hamamoto and X. Z. Zhang

1995-11-01T23:59:59.000Z

116

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

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

117

Neutron diffraction by perfect crystals  

Science Journals Connector (OSTI)

The dynamical theory of neutron diffraction has been formulated to include the reflected waves from the boundaries of a crystal. This formulation allows a unified treatment of the neutron optical and diffraction phenomena in crystals. It is shown that the neutron propagation in the crystal is determined by two structure factors characterizing the lattice: the total structure factor and the structure factor of the neutron-spin-neutron-orbit interaction. Diffraction by a parallel crystal plate has been studied in considerable detail. It has been found that for a definite neutron-spin orientation, the diffracted and transmitted beams are modulated by six terms periodic in the thickness of the crystal. The period of the dominant term, in this Pendellsung fringe structure, has been calculated in several cases of experimental importance. If the glancing angle of incidence substantially exceeds the critical angle for total reflection, the results are identical with those obtained by a simple extension, to the neutron case, of the x-ray dynamical theory. The diffraction by a magnetized crystal has been examined in some detail and it is shown that measurement of the Pendellsung periods for the two neutron-spin orientations may be used to determine both the nuclear and magnetic neutron scattering amplitude.

C. Stassis and J. A. Oberteuffer

1974-12-15T23:59:59.000Z

118

About UCN | Ultracold Neutrons at Los Alamos National Laboratory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Res. A. 599, 248 (2009). W. S. Wilburn et al. "Measurement of the neutrino-spin correlation parameter b in neutron decay using ultracold neutrons." Rev. Mex. Fis. 55, 119 (2009)...

119

Neutron reflectometry  

Science Journals Connector (OSTI)

Neutron reflectivity is a powerful tool for the ... chapter include: the theory of elastic specular neutron diffraction; polarized neutron reflectivity; surface roughness; experimental methodology; resolution in ...

G. S. Smith; C. F. Majkrzak

2004-01-01T23:59:59.000Z

120

Environment Assisted Metrology with Spin Qubit  

E-Print Network [OSTI]

We investigate the sensitivity of a recently proposed method for precision measurement [Phys. Rev. Lett. 106, 140502 (2011)], focusing on an implementation based on solid-state spin systems. The scheme amplifies a quantum sensor response to weak external fields by exploiting its coupling to spin impurities in the environment. We analyze the limits to the sensitivity due to decoherence and propose dynamical decoupling schemes to increase the spin coherence time. The sensitivity is also limited by the environment spin polarization; therefore we discuss strategies to polarize the environment spins and present a method to extend the scheme to the case of zero polarization. The coherence time and polarization determine a figure of merit for the environment's ability to enhance the sensitivity compared to echo-based sensing schemes. This figure of merit can be used to engineer optimized samples for high-sensitivity nanoscale magnetic sensing, such as diamond nanocrystals with controlled impurity density.

Cappellaro, P; Hodges, J S; Jiang, L; Maze, J R; Srensen, A S; Lukin, M D

2012-01-01T23:59:59.000Z

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.


121

Neutron-Neutron Interaction  

Science Journals Connector (OSTI)

The present status of the problem of charge dependence is discussed. The information about the neutron-neutron interaction derived from the two-neutron system, three-nucleon systems, final-state interactions in multiparticle reactions, and peripheral processes is critically evaluated. The experimental data indicate the breakdown of charge independence by about 3-5%. Evidence concerning the violation of charge symmetry is inconclusive, but it seems that most of the data are consistent with the assumption that charge symmetry is satisfied within 0.5-1%. The most suitable studies which might improve the knowledge of the neutron-neutron forces are indicated.

IVO LAUS

1967-07-01T23:59:59.000Z

122

Neutron scattering length of lithium and boron and their isotopes  

Science Journals Connector (OSTI)

Coherent neutron scattering lengths and free cross sections were measured in order to determine the spin dependent scattering lengths of the isotopes of Li and B.

L. Koester; K. Knopf; W. Waschkowski

1983-01-01T23:59:59.000Z

123

Microsoft Word - EchoPointCommunityWind_CX_2012.docx  

Broader source: Energy.gov (indexed) [DOE]

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.

124

Echoes of relativistic Landau levels in graphene and bilayer graphene  

Science Journals Connector (OSTI)

The problem of echo effects that can originate in graphene and bilayer graphene upon the generation of relativistic Landau levels in a quantizing magnetic field is considered. Graphene (bilayer graphene) is consi...

M. B. Belonenko; N. G. Lebedev; A. V. Zhukov

2012-03-01T23:59:59.000Z

125

Femtosecond accumulated photon echo in Er-doped fibers  

Science Journals Connector (OSTI)

We report the observation of accumulated photon echo in Er-doped fibers. We also demonstrate time reversal and autoconvolution of femtosecond pulses, which suggest that Er-doped fibers...

da Silva, V L; Silberberg, Y; Heritage, J P; Chase, E W; Saifi, M A; Andrejco, M J

1991-01-01T23:59:59.000Z

126

Coherence rephasing combined with spin-wave storage using chirped control pulses  

E-Print Network [OSTI]

Photon-echo based optical quantum memory schemes often employ intermediate steps to transform optical coherences to spin coherences for longer storage times. We analyze a scheme that uses three identical chirped control pulses for coherence rephasing in an inhomogeneously broadened ensemble of three-level $\\Lambda$-systems. The pulses induce a cyclic permutation of the atomic populations in the adiabatic regime. Optical coherences created by a signal pulse are stored as spin coherences at an intermediate time interval, and are rephased for echo emission when the ensemble is returned to the initial state. Echo emission during a possible partial rephasing when the medium is inverted can be suppressed with an appropriate choice of control pulse wavevectors. We demonstrate that the scheme works in an optically dense ensemble, despite control pulse distortions during propagation. It integrates conveniently the spin-wave storage step into memory schemes based on a second rephasing of the atomic coherences.

Gabor Demeter

2014-03-19T23:59:59.000Z

127

Ris-PhD-7(EN) Neutron scattering studies of two-  

E-Print Network [OSTI]

Risø-PhD-7(EN) Neutron scattering studies of two- dimensional antiferromagnetic spin fluctuations Denmark January 2005 #12;Neutron scattering studies of two-dimensional antiferromagnetic spin fluctuations Laboratory 4000 Roskilde, Denmark #12;#12;Abstract: In this thesis, neutron scattering techniques are used

128

Absence of exponential sensitivity to small perturbations in nonintegrable systems of spins 1/2  

Science Journals Connector (OSTI)

We show that macroscopic nonintegrable lattices of spins 1/2, which are often considered to be chaotic, do not exhibit the basic property of classical chaotic systems, namely, exponential sensitivity to small perturbations. We compare chaotic lattices of classical spins and nonintegrable lattices of spins 1/2 in terms of their magnetization responses to an imperfect reversal of spin dynamics known as Loschmidt echo. In the classical case, magnetization is exponentially sensitive to small perturbations with a characteristic exponent equal to twice the value of the largest Lyapunov exponent of the system. In the case of spins 1/2, magnetization is only power-law sensitive to small perturbations.

B. V. Fine; T. A. Elsayed; C. M. Kropf; A. S. de Wijn

2014-01-31T23:59:59.000Z

129

Neutron Polarimetry  

Science Journals Connector (OSTI)

8 July 1993 research-article Neutron Polarimetry P. Jane Brown J. Bruce Forsyth Francis Tasset Zero-field neutron polarimetry is a technique which has...polarization analysis to be carried out in a neutron scattering experiment. The incident...

1993-01-01T23:59:59.000Z

130

Refocusing dipolar interactions between electronic spins of donors in silicon  

E-Print Network [OSTI]

We note the existence of a set of magnetic field values where a simple Hahn echo sequence refocuses the dynamics of the full dipolar interaction, for spin systems of electron donors in silicon. As the refocussing occurs for both arbitrary coupling strengths and arbitrary times, these dipolar refocusing points (DRPs) offer new possibilities for regulating entanglement due to the always-on spin dipolar interaction. While the experimental effects of DRPs will be strongly diluted in the measured coherences of thermal (unpolarized) spin ensembles, we investigate possible signatures in coherence decays arising from a study of the combined effects of decoherence arising from instantaneous diffusion and direct flip-flops

T. S. Monteiro

2014-12-08T23:59:59.000Z

131

Quantum Decoherence of the Central Spin in a Sparse System of Dipolar Coupled Spins  

E-Print Network [OSTI]

The central spin decoherence problem has been researched for over 50 years in the context of both nuclear magnetic resonance and electron spin resonance. Until recently, theoretical models have employed phenomenological stochastic descriptions of the bath-induced noise. During the last few years, cluster expansion methods have provided a microscopic, quantum theory to study the spectral diffusion of a central spin. These methods have proven to be very accurate and efficient for problems of nuclear-induced electron spin decoherence in which hyperfine interactions with the central electron spin are much stronger than dipolar interactions among the nuclei. We provide an in-depth study of central spin decoherence for a canonical scale-invariant all-dipolar spin system. We show how cluster methods may be adapted to treat this problem in which central and bath spin interactions are of comparable strength. Our extensive numerical work shows that a properly modified cluster theory is convergent for this problem even as simple perturbative arguments begin to break down. By treating clusters in the presence of energy detunings due to the long-range (diagonal) dipolar interactions of the surrounding environment and carefully averaging the effects over different spin states, we find that the nontrivial flip-flop dynamics among the spins becomes effectively localized by disorder in the energy splittings of the spins. This localization effect allows for a robust calculation of the spin echo signal in a dipolarly coupled bath of spins of the same kind, while considering clusters of no more than 6 spins. We connect these microscopic calculation results to the existing stochastic models. We, furthermore, present calculations for a series of related problems of interest for candidate solid state quantum bits including donors and quantum dots in silicon as well as nitrogen-vacancy centers in diamond.

Wayne M. Witzel; Malcolm S. Carroll; Lukasz Cywinski; S. Das Sarma

2012-08-02T23:59:59.000Z

132

The precursor phase of the CMR metallic state probed by spin and lattice dynamics  

E-Print Network [OSTI]

, the origin of which is still unclear. In this paper, we mainly review and discuss neutron scattering studies inelastic neutron scattering. In the three systems, and over the whole temperature range, the spin

Boyer, Edmond

133

Polarized neutron diffraction at a spallation source for magnetic studies  

Science Journals Connector (OSTI)

The first results from polarized neutron diffraction experiments on a time-of-flight instrument at a spallation source are reported. Higher neutron beam flux and efficient spin polarization at the neutron beamline enable in situ studies of phenomena contributing to field-induced magnetization in materials including magnetic shape memory alloys.

Pramanick, A.

2012-09-01T23:59:59.000Z

134

Polarization Analysis of Thermal-Neutron Scattering  

Science Journals Connector (OSTI)

A triple-axis neutron spectrometer with polarization-sensitive crystals on both the first and third axes is described. The calculation of polarized-neutron scattering cross sections is presented in a form particularly suited to apply to this instrument. Experimental results on nuclear incoherent scattering, paramagnetic scattering, Bragg scattering, and spin-wave scattering are presented to illustrate the possible applications of neutron-polarization analysis.

R. M. Moon; T. Riste; W. C. Koehler

1969-05-10T23:59:59.000Z

135

Neutron Production, Neutron Facilities and Neutron Instrumentation  

Science Journals Connector (OSTI)

...Mexico, 87545, U.S.A, e-mail: sven@lanl.gov Hans-Georg Priesmeyer Geesthacht Neutron Scattering Facility, GKSS Research Center, 21502 Geesthacht, Germany, e-mail: hans-georg.priesmeyer@gkss.de NEUTRON GENERATION The...

Sven C. Vogel; Hans-Georg Priesmeyer

136

Neutron Reflectivity  

Science Journals Connector (OSTI)

Neutron Reflectivity ... This article is part of the Neutron Reflectivity special issue. ... The articles in this special issue on neutron reflectivity cover a broad range of the applications of this technique and the related X-ray and neutron scattering experiments of SAXS, SANS, GISAXS, and GISANS. ...

Jeffrey Penfold

2009-03-31T23:59:59.000Z

137

Light Loop Echoes and Blinking Black Holes  

E-Print Network [OSTI]

Radiation emitted near a black hole reaches the observer by multiple paths; and when this radiation varies in time, the time-delays between the various paths generate a "blinking" effect in the observed light curve L(t) or its auto-correlation function xi(T)= . For the particularly important "face-on" configuration (in which the hole is viewed roughly along its spin axis, while the emission comes roughly from its equatorial plane -- e.g. from the inner edge of its accretion disk, or from the violent flash of a nearby/infalling star) we calculate the blinking in detail by computing the time delay Delta t_{j}(r,a) and magnification mu_{j}(r,a) of the jth path (j=1,2,3,...), relative to the primary path (j=0), as a function of the emission radius r and black hole spin 0

138

About Neutrons  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

139

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

Broader source: Energy.gov (indexed) [DOE]

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

140

Echo Meadows Project Winter Artificial Recharge.  

SciTech Connect (OSTI)

This report discusses the findings of the Echo Meadows Project (BPA Project 2001-015-00). The main purpose of this project is to artificially recharge an alluvial aquifer, WITH water from Umatilla River during the winter high flow period. In turn, this recharged aquifer will discharge an increased flow of cool groundwater back to the river, thereby improving Umatilla River water quality and temperature. A considerable side benefit is that the Umatilla River should improve as a habitat for migration, spanning, and rearing of anadromous and resident fish. The scope of this project is to provide critical baseline information about the Echo Meadows and the associated reach of the Umatilla River. Key elements of information that has been gathered include: (1) Annual and seasonal groundwater levels in the aquifer with an emphasis on the irrigation season, (2) Groundwater hydraulic properties, particularly hydraulic conductivity and specific yield, and (3) Groundwater and Umatilla River water quality including temperature, nutrients and other indicator parameters. One of the major purposes of this data gathering was to develop input to a groundwater model of the area. The purpose of the model is to estimate our ability to recharge this aquifer using water that is only available outside of the irrigation season (December through the end of February) and to estimate the timing of groundwater return flow back to the river. We have found through the data collection and modeling efforts that this reach of the river had historically returned as much as 45 cubic feet per second (cfs) of water to the Umatilla River during the summer and early fall. However, this return flow was reduced to as low as 10 cfs primarily due to reduced quantities of irrigation application, gain in irrigation efficiencies and increased groundwater pumping. Our modeling indicated that it is possible to restore these critical return flows using applied water outside of the irrigation season. We further found that this water can be timed to return to the river during the desired time of the year (summer to early fall). This is because the river stage, which remains relatively high until this time, drops during the irrigation season-thereby releasing the stored groundwater and increasing river flows. A significant side benefit is that these enhanced groundwater return flows will be clean and cold, particularly as compared to the Umatilla River. We also believe that this same type of application of water could be done and the resulting stream flows could be realized in other watersheds throughout the Pacific Northwest. This means that it is critical to compare the results from this baseline report to the full implementation of the project in the next phase. As previously stated, this report only discusses the results of data gathered during the baseline phase of this project. We have attempted to make the data that has been gathered accessible with the enclosed databases and spreadsheets. We provide computer links in this report to the databases so that interested parties can fully evaluate the data that has been gathered. However, we cannot emphasize too strongly that the real value of this project is to implement the phases to come, compare the results of these future phases to this baseline and develop the science and strategies to successfully implement this concept to other rivers in the Pacific Northwest. The results from our verified and calibrated groundwater model matches the observed groundwater data and trends collected during the baseline phase. The modeling results indicate that the return flows may increase to their historic values with the addition of 1 acre-ft/acre of recharge water to the groundwater system (about 9,600 acre-feet total). What this means is that through continued recharge project, you can double to quadruple the annual baseflow of the Umatilla River during the low summer and fall flow periods as compared to the present base-flow. The cool and high quality recharge water is a significant beneficial impact to the river system.

Ziari, Fred

2002-12-19T23:59:59.000Z

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

Algorithms for processing ultrasonic echo data for height control systems  

E-Print Network [OSTI]

estimation was affected by the value of the weighting factor (M) in equation (1). The accuracy of this stubble height estimation was evaluated by using the Student's t test technique. ESTH(n) = AVS(n) ? AVG(n) (3) Computer program: A FORTRAN program... YES IS HTs'P READ AVS & AVG, STALK AND GROUND AVERAGES r---- RAISE BLADES t, READ THD OR THH & THL, SINGLE THRESHOLD OR GET NEW SAMPLE ECHO ECHO DISCRIMINATION GROUND STALK OR GROUND ? STALK AVS ~AVS + Y(I)-AVS n n-I AVG =AVG Y...

Lin, Reng Rong

2012-06-07T23:59:59.000Z

142

Neutron Scattering Application of Polarized Solid Target in Materials Research  

SciTech Connect (OSTI)

Neutron scattering is one of the most important tools for materials research. However, neutrons are very expensive to produce. Even with the best sources, such as the newly completed Spallation Neutron Source at the Oak Ridge National Laboratory, most neutron scattering experiments are still flux limited. One way to improve the experimental data is polarized neutron scattering from polarized solid target: the strong spin-dependent neutron scattering cross-section can increase the coherent scattering and decrease the incoherent scattering at the same time, thereby significantly enhancing the signal to noise ratio. Hydrogen, abundant in most soft condensed matters, has a strong spin-dependent scattering cross-section. Early applications of polarized neutron scattering in biological soft condensed matters have already demonstrated the huge potential of this technique. Here we describe the polarized target program at the SNS. The program is under active construction and is aimed at serving neutron scattering at the SNS.

Zhao, Jinkui [ORNL

2008-09-01T23:59:59.000Z

143

Parallel and real-time implementation of an acoustic echo canceller using oversampled wavelet frame algorithms  

E-Print Network [OSTI]

This thesis describes a novel echo cancellation system that eliminates nonstationary echoes with long acoustic delays in real-time. By combining subband adaptive filtering and active system identification based on fast wavelet transform...

Tam, Pak-Yin

2012-06-07T23:59:59.000Z

144

Bulk Hook Echo Raindrop Sizes Retrieved Using Mobile, Polarimetric Doppler Radar Observations  

Science Journals Connector (OSTI)

Polarimetric radar observations obtained by the NOAA (NSSL) mobile, X-band, dual-polarization radar (NOXP) are used to investigate hook echo precipitation properties in several tornadic and non-tornadic supercells. Hook echo drop size ...

Michael M. French; Donald W. Burgess; Edward R. Mansell; Louis J. Wicker

145

Measuring the Neutron Lifetime Using Magnetically Trapped Neutrons  

E-Print Network [OSTI]

The neutron beta-decay lifetime plays an important role both in understanding weak interactions within the framework of the Standard Model and in theoretical predictions of the primordial abundance of 4He in Big Bang Nucleosynthesis. In previous work, we successfully demonstrated the trapping of ultracold neutrons (UCN) in a conservative potential magnetic trap. A major upgrade of the apparatus is nearing completion at the National Institute of Standards and Technology Center for Neutron Research (NCNR). In our approach, a beam of 0.89 nm neutrons is incident on a superfluid 4He target within the minimum field region of an Ioffe-type magnetic trap. A fraction of the neutrons is downscattered in the helium to energies <200 neV, and those in the appropriate spin state become trapped. The inverse process is suppressed by the low phonon density of helium at temperatures less than 200 mK, allowing the neutron to travel undisturbed. When the neutron decays the energetic electron ionizes the helium, producing scintillation light that is detected using photomultiplier tubes. Statistical limitations of the previous apparatus will be alleviated by significant increases in field strength and trap volume resulting in twenty times more trapped neutrons.

C. M. O'Shaughnessy; R. Golub; K. W. Schelhammer; C. M. Swank; P. -N. Seo; P. R. Huffman; S. N. Dzhosyuk; C. E. H. Mattoni; L. Yang; J. M. Doyle; K. J. Coakley; A. K. Thompson; H. P. Mumm; S. K. Lamoreaux; G. Yang

2009-03-31T23:59:59.000Z

146

Finland HF and Esrange MST radar observations of polar mesosphere summer echoes  

E-Print Network [OSTI]

Finland HF and Esrange MST radar observations of polar mesosphere summer echoes Tadahiko Ogawa1 (200x) xx:1­8 Finland HF and Esrange MST radar observations of polar mesosphere summer echoes Tadahiko in Finland are presented. The echoes were detected at four frequencies of 9, 11, 13 and 15 MHz at slant

Kirkwood, Sheila

147

Neutron-Neutron Scattering Length  

Science Journals Connector (OSTI)

The final-state interaction of the two neutrons from the reaction ?-+d?2n+? has a pronounced and distinctive effect on the momentum spectrum of the outgoing particles. In particular, the neutron spectrum is sharply peaked in the neighborhood of 2 Mev, with a shape that is quite sensitive to the strength of the nn interaction. In the region of this peak, the relative neutron-neutron momentum is so small that the nn interaction is completely characterized by its scattering length. Hence it is proposed that a measurement of the shape of the neutron spectrum from this reaction may provide a convenient means of measuring the neutron-neutron scattering length. Neutron spectra are calculated in an impulse approximation, for several assumed values of the scattering length. It appears from their shapes that, in this way, present neutron-detection techniques should be capable of determining the scattering length to within 25%.

Kirk W. McVoy

1961-03-01T23:59:59.000Z

148

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":""}]}

149

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":""}]}

150

Interference effects in IR photon echo spectroscopy of liquid water  

SciTech Connect (OSTI)

Heterodyne-detected transient grating experiments on the OH-stretch mode of HDO dissolved in D{sub 2}O resolve two distinctly different contributions originating from the initially excited OH stretch and the OD stretch which is thermally activated during the OH population relaxation. It is demonstrated that interference of both contributions greatly affects the outcome of IR photon echo experiments.

Yeremenko, Sergey; Pshenichnikov, Maxim S.; Wiersma, Douwe A. [Ultrafast Laser and Spectroscopy Laboratory, Materials Science Centre, University of Groningen, Nijenborgh 4, 9747 AG Groningen (Netherlands)

2006-02-15T23:59:59.000Z

151

Neutron skins and neutron stars  

SciTech Connect (OSTI)

The neutron-skin thickness of heavy nuclei provides a fundamental link to the equation of state of neutron-rich matter, and hence to the properties of neutron stars. The Lead Radius Experiment ('PREX') at Jefferson Laboratory has recently provided the first model-independence evidence on the existence of a neutron-rich skin in {sup 208}Pb. In this contribution we examine how the increased accuracy in the determination of neutron skins expected from the commissioning of intense polarized electron beams may impact the physics of neutron stars.

Piekarewicz, J. [Department of Physics, Florida State University, Tallahassee, FL 32306-4350 (United States)

2013-11-07T23:59:59.000Z

152

Neutron scattering  

Science Journals Connector (OSTI)

... likely to be able to contribute to many different branches of chemistry and secondly because neutron ...neutronscattering ...

A. J. Leadbetter

1977-12-01T23:59:59.000Z

153

Neutron guide  

DOE Patents [OSTI]

A neutron guide in which lengths of cylindrical glass tubing have rectangular glass plates properly dimensioned to allow insertion into the cylindrical glass tubing so that a sealed geometrically precise polygonal cross-section is formed in the cylindrical glass tubing. The neutron guide provides easier alignment between adjacent sections than do the neutron guides of the prior art.

Greene, Geoffrey L. (Los Alamos, NM)

1999-01-01T23:59:59.000Z

154

Neutron Diffraction  

Science Journals Connector (OSTI)

22 February 1949 research-article Neutron Diffraction G. E. Bacon J. Thewlis The problem of neutron diffraction by crystals is treated by analogy...deals with a comparison between X-ray and neutron diffraction and it is shown that quantitatively...

1949-01-01T23:59:59.000Z

155

Polarization analysis of neutron reflectometry on non-collinear magnetic media: polarized neutron reflectometry experiments on a thin cobalt film  

Science Journals Connector (OSTI)

In this work we present a full data analysis of polarized neutron reflectometry experiments on a thin magnetic film. A magnetic field was applied perpendicular to the layer magnetization, resulting in non spin-flip and spin-flip reflectivities. For moderate external fields, the gain or loss of Zeeman energy for spin-flipped neutrons results in off-specular reflected spin-flipped beams. The theoretical model used to explain all data simultaneously consists of a bulk cobalt layer, together with interfacial layers with low magnetization values.

R.W.E van de Kruijs; H Fredrikze; M.Th Rekveldt; A.A van Well; Yu.V Nikitenko; V.G Syromyatnikov

2000-01-01T23:59:59.000Z

156

Measuring the Neutron Lifetime Using Magnetically Trapped Neutrons  

E-Print Network [OSTI]

The neutron beta-decay lifetime plays an important role both in understanding weak interactions within the framework of the Standard Model and in theoretical predictions of the primordial abundance of 4He in Big Bang Nucleosynthesis. In previous work, we successfully demonstrated the trapping of ultracold neutrons (UCN) in a conservative potential magnetic trap. A major upgrade of the apparatus is nearing completion at the National Institute of Standards and Technology Center for Neutron Research (NCNR). In our approach, a beam of 0.89 nm neutrons is incident on a superfluid 4He target within the minimum field region of an Ioffe-type magnetic trap. A fraction of the neutrons is downscattered in the helium to energies <200 neV, and those in the appropriate spin state become trapped. The inverse process is suppressed by the low phonon density of helium at temperatures less than 200 mK, allowing the neutron to travel undisturbed. When the neutron decays the energetic electron ionizes the helium, producing sci...

O'Shaughnessy, C M; Schelhammer, K W; Swank, C M; Seo, P -N; Huffman, P R; Dzhosyuk, S N; Mattoni, C E H; Yang, L; Doyle, J M; Coakley, K J; Thompson, A K; Mumm, H P; Lamoreaux, S K; Yang, G

2009-01-01T23:59:59.000Z

157

Synthesize Neutron-Drip-Line-Nuclides with Free-Neutron Bose-Einstein Condensates Experimentally  

E-Print Network [OSTI]

We first show a possible way to create a new type of matter, free-neutron Bose-Einstein condensate by the ultracold free-neutron-pair Bose-Einstein condensation and then determine the neutron drip line experimentally. The Bose-Einstein condensation of bosonic and fermionic atoms in atomic gases was performed experimentally and predicted theoretically early. Neutrons are similar to fermionic atoms. We found free neutrons could be cooled to ultracold neutrons with very low energy by other colder neutral atoms which are cooled by the laser. These neutrons form neutron pairs with spin zero, and then ultracold neutron-pairs form Bose-Einstein condensate. Our results demonstrate how these condensates can react with accelerated ion beams at different energy to synthesize very neutron-rich nuclides near, on or/and beyond the neutron drip line, to determine the neutron drip line and whether there are long-life nuclide or isomer islands beyond the neutron drip line experimentally. Otherwise, these experimental results will confirm our prediction that is in the whole interacting region or distance of nuclear force in all energy region from zero to infinite, Only repulsive nuclear force exists among identical nucleons and only among different nucleons exists attractive nuclear force.

Bao-Guo Dong

2014-09-22T23:59:59.000Z

158

Polarized neutron reflectometry in high magnetic fields  

SciTech Connect (OSTI)

A simple method is described to maintain the polarization of a neutron beam on its way through the large magnetic stray fields produced by a vertical field of a cryomagnet with a split-coil geometry. The two key issues are the proper shielding of the neutron spin flippers and an additional radial field component in order to guide the neutron spin through the region of the null point (i.e., point of reversal for the vertical field component). Calculations of the neutron's spin rotation as well as polarized neutron reflectometry experiments on an ErFe{sub 2}/DyFe{sub 2} multilayer show the perfect performance of the used setup. The recently commissioned cryomagnet M5 with a maximum vertical field of up to 7.2 T in asymmetric mode for polarized neutrons and 9 T in symmetric mode for unpolarized neutrons was used on the C5 spectrometer in reflectometry mode, at the NRU reactor in Chalk River, Canada.

Fritzsche, H. [National Research Council Canada, Canadian Neutron Beam Centre, Chalk River Laboratories, Chalk River, Ontario K0J 1J0 (Canada)

2005-11-15T23:59:59.000Z

159

Superconductivity | ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

160

Echoes from the companion star in Sco X-1  

E-Print Network [OSTI]

We present simultaneous X-ray (RXTE) and optical (ULTRACAM) narrow band (Bowen blend/HeII and nearby continuum) observations of Sco X-1 at 2-10 Hz time resolution. We find that the Bowen/HeII emission lags the X-ray light-curves with a light travel time of ~11-16s which is consistent with reprocessing in the companion star. The echo from the donor is detected at orbital phase ~0.5 when Sco X-1 is at the top of the Flaring Branch. Evidence of echoes is also seen at the bottom of the Flaring Branch but with time-lags of 5-10s which are consistent with reprocessing in an accretion disc with a radial temperature profile. We discuss the implication of our results for the orbital parameters of Sco X-1.

T. Muoz-Darias; I. G. Martinez-Pais; J. Casares; V. S. Dhillon; T. R. Marsh; R. Cornelisse; D. Steeghs; P. A. Charles

2007-05-31T23:59:59.000Z

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

Benefits of the Multiple Echo Technique for Ultrasonic Thickness Testing  

SciTech Connect (OSTI)

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

162

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":""}]}

163

Neutron skins and neutron stars  

Science Journals Connector (OSTI)

Background: The neutron skin of a heavy nucleus as well as many neutron-star properties are highly sensitive to the poorly constrained density dependence of the symmetry energy.Purpose: To provide for the first time meaningful theoretical errors and to assess the degree of correlation between the neutron-skin thickness of 208Pb and several neutron-star properties.Methods: A proper covariance analysis based on the predictions of an accurately calibrated relativistic functional FSUGold is used to quantify theoretical errors and correlation coefficients.Results: We find correlation coefficients of nearly 1 (or ?1) between the neutron-skin thickness of 208Pb and a host of observables of relevance to the structure, dynamics, and composition of neutron stars.Conclusions: We suggest that a follow-up Lead Radius Experiment (PREX) measurement, ideally with a 0.5% accuracy, could significantly constrain the equation of state of neutron-star matter.

F. J. Fattoyev and J. Piekarewicz

2012-07-05T23:59:59.000Z

164

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

165

Neutron Scattering Tutorials | Neutron Science | ORNL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Neutron Scattering Tutorials SHARE Neutron Scattering Tutorials The following lectures were presented at the 2011 and 2010 National School on Neutron & X-Ray Scattering. This...

166

Magnetism Highlights| Neutron Science | ORNL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

167

Research Highlights | ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

168

The Visible and Near Infrared module of EChO  

E-Print Network [OSTI]

The Visible and Near Infrared (VNIR) is one of the modules of EChO, the Exoplanets Characterization Observatory proposed to ESA for an M-class mission. EChO is aimed to observe planets while transiting by their suns. Then the instrument had to be designed to assure a high efficiency over the whole spectral range. In fact, it has to be able to observe stars with an apparent magnitude Mv= 9-12 and to see contrasts of the order of 10-4 - 10-5 necessary to reveal the characteristics of the atmospheres of the exoplanets under investigation. VNIR is a spectrometer in a cross-dispersed configuration, covering the 0.4-2.5 micron spectral range with a resolving power of about 330 and a field of view of 2 arcsec. It is functionally split into two channels respectively working in the 0.4-1 and 1.0-2.5 micron spectral ranges. Such a solution is imposed by the fact the light at short wavelengths has to be shared with the EChO Fine Guiding System (FGS) devoted to the pointing of the stars under observation. The spectromete...

Adriani, A; Gambicorti, L; Focardi, M; Oliva, E; Farina, M; Di Giorgio, A M; Santoli, F; Pace, E; Piccioni, G; Filacchione, G; Pancrazzi, M; Tozzi, A; Micela, G

2014-01-01T23:59:59.000Z

169

Demonstration of improved sensitivity of echo interferometers to gravitational acceleration  

E-Print Network [OSTI]

We have developed two configurations of an echo interferometer that rely on standing wave excitation of a laser-cooled sample of rubidium atoms that measures acceleration. For a two-pulse configuration, the interferometer signal is modulated at the recoil frequency and exhibits a sinusoidal frequency chirp as a function of pulse spacing. For a three-pulse stimulated echo configuration, the signal is observed without recoil modulation and exhibits a modulation at a single frequency. The three-pulse configuration is less sensitive to effects of vibrations and magnetic field curvature leading to a longer experimental timescale. For both configurations of the atom interferometer (AI), we show that a measurement of acceleration with a statistical precision of 0.5% can be realized by analyzing the shape of the echo envelope that has a temporal duration of a few microseconds. Using the two-pulse AI, we obtain measurements of acceleration that are statistically precise to 6 parts per million (ppm) on a 25 ms timescal...

Mok, C; Carew, A; Berthiaume, R; Beattie, S; Kumarakrishnan, A

2013-01-01T23:59:59.000Z

170

Detection of a Light Echo from the Otherwise Normal SN 2007af  

E-Print Network [OSTI]

We present the discovery of a light echo from SN 2007af, a normal Type Ia supernova (SN Ia) in NGC 5584. Hubble Space Telescope (HST) images taken three years post explosion reveal two separate echoes; an outer echo and extended central region, which we propose as an unresolved inner echo. Multiple images were obtained in the F160W, F350LP, F555W, and F814W using the Wide Field Camera 3. If the outer echo is produced by an interstellar dust sheet perpendicular to the line of sight, it is located ~800 pc in front of the SN. The dust for the inner echo is 0.45 pc < d < 90 pc away from the SN. The inner echo color is consistent with typical interstellar dust wavelength-dependent scattering cross-sections, while the outer echo color does not match the predictions. Both dust sheets, if in the foreground, are optically thin for scattering, with the outer echo sheet thickness consistent with the inferred extinction from peak brightness. Whether the inner echo is from interstellar or circumstellar dust is ambig...

Drozdov, D; Milne, P A; Pearcy, J; Riess, A G; Macri, L M; Bryngelson, G L; Garnavich, P M

2014-01-01T23:59:59.000Z

171

Neutron detector  

DOE Patents [OSTI]

A neutron detector has a volume of neutron moderating material and a plurality of individual neutron sensing elements dispersed at selected locations throughout the moderator, and particularly arranged so that some of the detecting elements are closer to the surface of the moderator assembly and others are more deeply embedded. The arrangement captures some thermalized neutrons that might otherwise be scattered away from a single, centrally located detector element. Different geometrical arrangements may be used while preserving its fundamental characteristics. Different types of neutron sensing elements may be used, which may operate on any of a number of physical principles to perform the function of sensing a neutron, either by a capture or a scattering reaction, and converting that reaction to a detectable signal. High detection efficiency, an ability to acquire spectral information, and directional sensitivity may be obtained.

Stephan, Andrew C. (Knoxville, TN); Jardret; Vincent D. (Powell, TN)

2011-04-05T23:59:59.000Z

172

Neutron Scattering  

Science Journals Connector (OSTI)

... Magnetic Neutron Diffraction By Yurii A. Izyumov and Ruslan P. Ozerov. Translated from the Russian. ... York; Heydon: London, June 1970.) 350s; $37.50; 150 DM.

G. L. SQUIRES

1970-12-05T23:59:59.000Z

173

Polarized neutron reflectometry with phase analysis  

Science Journals Connector (OSTI)

A novel technique, polarized neutron reflectometry with phase analysis (PNRPA), is suggested, in which not only the moduli of reflection matrix elements but also up to three phase differences are measured. It is realized in the scheme with two flippers and an analyzer, by reflection of neutrons with the spin, in succession, parallel and antiparallel to two inclined axes fixed to the sample. More detailed information about magnetic layered structures can be thus obtained. An adequate mathematical formalism is given.

N.K. Pleshanov

1999-01-01T23:59:59.000Z

174

Accumulated photon echo in ruby under hydrostatic pressure: Ground-state splitting and spontaneous decay of 2A(2E)  

Science Journals Connector (OSTI)

The technique of accumulated photon echo is used in combination with a high-pressure diamond anvil cell to measure the splitting of the 4A2 ground state and the one-phonon spontaneous decay rate of the 2A(2E) level at 1.5 K in ruby up to 4.3 GPa of hydrostatic pressure. The 4A2 ground-state splitting is found to be 0.3830.001 cm-1 at ambient pressure, and increases with a slope of +(61)10-3 cm-1/GPa. The spontaneous decay rate of 2A(2E) increases only weakly with pressure. The pressure dependences of both quantities are accounted for in terms of the trigonal-field and spin-orbit-coupling parameters.

M. H. F. Overwijk; J. I. Dijkhuis; H. W. de Wijn; R. Vreeker; R. Sprik; A. Lagendijk

1991-06-01T23:59:59.000Z

175

Neutron activation analysis  

Science Journals Connector (OSTI)

Neutron activation analysis ... Describes the science and techniques of neutron activation analysis. ...

H. R. Lukens

1967-01-01T23:59:59.000Z

176

Spin Stability  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

177

Neutron Microscope  

Science Journals Connector (OSTI)

We report successful operation of a neutron microscope using ultracold neutrons at the high-flux reactor at Grenoble. A sharp, achromatic image of an object slit was obtained at a magnification of 50. The measured resolution of 0.1 mm was limited mainly by the available beam intensity, not by aberrations.

P. Herrmann; K. -A. Steinhauser; R. Ghler; A. Steyerl; W. Mampe

1985-05-06T23:59:59.000Z

178

Neutron scattering  

Science Journals Connector (OSTI)

... statements that the EMBL outstation in Grenoble "[has an] uncertain future" and that "neutrons have not turned out to be particularly useful for biologists" in Peter Newmark's ... on the European Molecular Biology Laboratory (Nature 338, 724; 1989) require some comment.Neutron ...

S. CUSACK; B. JACROT; R. LEBERMAN; R. MAY; P. TlMMINS; G. ZACCAI

1989-06-01T23:59:59.000Z

179

Neutron shell structure and deformation in neutron-drip-line nuclei  

E-Print Network [OSTI]

Neutron shell-structure and the resulting possible deformation in the neighborhood of neutron-drip-line nuclei are systematically discussed, based on both bound and resonant neutron one-particle energies obtained from spherical and deformed Woods-Saxon potentials. Due to the unique behavior of weakly-bound and resonant neutron one-particle levels with smaller orbital angular-momenta $\\ell$, a systematic change of the shell structure and thereby the change of neutron magic-numbers are pointed out, compared with those of stable nuclei expected from the conventional j-j shell-model. For spherical shape with the operator of the spin-orbit potential conventionally used, the $\\ell_{j}$ levels belonging to a given oscillator major shell with parallel spin- and orbital-angular-momenta tend to gather together in the energetically lower half of the major shell, while those levels with anti-parallel spin- and orbital-angular-momenta gather in the upper half. The tendency leads to a unique shell structure and possible deformation when neutrons start to occupy the orbits in the lower half of the major shell. Among others, the neutron magic-number N=28 disappears and N=50 may disappear, while the magic number N=82 may presumably survive due to the large $\\ell =5$ spin-orbit splitting for the $1h_{11/2}$ orbit. On the other hand, an appreciable amount of energy gap may appear at N=16 and 40 for spherical shape, while neutron-drip-line nuclei in the region of neutron number above N=20, 40 and 82, namely N $\\approx$ 21-28, N $\\approx$ 41-54, and N $\\approx$ 83-90, may be quadrupole-deformed though the possible deformation depends also on the proton number of respective nuclei.

Ikuko Hamamoto

2012-05-29T23:59:59.000Z

180

Tests of time reversal in neutron?nucleus scattering  

Science Journals Connector (OSTI)

Experiments to test time?reversal invariance are discussed. The experiments are based on observables constructed from the momentum and spin vectors of epithermal neutrons and from the spin of an aligned or polarized target. It is shown that the proposed tests are detailed balance tests of time?reversal invariance. The status of the experiments is briefly reviewed.

J. David Bowman

1988-01-01T23:59:59.000Z

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.


181

Information erasing in the phenomenon of long-lived photon echo  

Science Journals Connector (OSTI)

The possibility of erasing information in an arbitrary cell of an optical memory device based on the phenomenon of long-lived photon echo is theoretically considered. Optimal...

Akhmediev, N N

1990-01-01T23:59:59.000Z

182

Constraints on anomalous spin-spin interactions from spin-exchange collisions  

SciTech Connect (OSTI)

A comparison between existing measurements and calculated cross sections for spin exchange between alkali-metal atoms and noble gases (specifically sodium and helium) is used to constrain anomalous spin-dependent forces between nuclei at the atomic scale ({approx}10{sup -8} cm). Combined with existing stringent limits on anomalous short-range, spin-dependent couplings of the proton, the dimensionless coupling constant for an axial vector interaction of the neutron arising from exchange of a boson of mass < or approx. 100 eV is constrained to be g{sub A}{sup n}/{radical}(4{pi}({h_bar}/2{pi})c)<2x10{sup -3}. Constraints are established for a velocity- and spin-dependent interaction {proportional_to}(I{center_dot}v)(K{center_dot}v), where I and K are the nuclear spins of He and Na, respectively, and v is the relative velocity of the atoms. Constraints on torsion gravity are also considered.

Jackson Kimball, D. F.; Boyd, Alec; Budker, D. [Department of Physics, California State University-East Bay, Hayward, California 94542-3084 (United States); Physics and Astronomy Department, Pomona College, Claremont, California 91711-6324 (United States); Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, and Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2010-12-15T23:59:59.000Z

183

Constraints on anomalous spin-spin interactions from spin-exchange collisions  

E-Print Network [OSTI]

Measured and calculated cross sections for spin-exchange between alkali atoms and noble gases (specifically sodium and helium) are used to constrain anomalous spin-dependent forces between nuclei at the atomic scale ($\\sim 10^{-8}~{\\rm cm}$). Combined with existing stringent limits on anomalous short-range, spin-dependent couplings of the proton, the dimensionless coupling constant for a heretofore undiscovered axial vector interaction of the neutron arising from exchange of a boson of mass $\\lesssim 100~{\\rm eV}$ is constrained to be $g_A^n/\\sqrt{4 \\pi \\hbar c} < 2 \\times 10^{-3}$. Constraints are established for a velocity- and spin-dependent interaction $\\propto \\prn{\\mathbf{I} \\cdot \\mathbf{v}} \\prn{\\mathbf{K} \\cdot \\mathbf{v}}$, where $\\mathbf{I}$ and $\\mathbf{K}$ are the nuclear spins of He and Na, respectively, and $\\mathbf{v}$ is the relative velocity of the atoms. Constraints on torsion gravity are also considered.

D. F. Jackson Kimball; Alec Boyd; D. Budker

2010-10-07T23:59:59.000Z

184

Neutron Experiment descriptions: N1: Triple-Axis Spectrometers, HFIR HB1A & HB3  

E-Print Network [OSTI]

Neutron Experiment descriptions: N1: Triple-Axis Spectrometers, HFIR HB1A & HB3 Spin wave2A Magnetic structure of NiO Neutron diffraction measurements will be performed to investigate 600K to 288K, using the Neutron Powder Diffractometer at the HFIR. Rietveld analysis of the crystal

Pennycook, Steve

185

Investigating Neutron Polarizabilities through Compton Scattering on $^3He$  

E-Print Network [OSTI]

We examine manifestations of neutron electromagnetic polarizabilities in coherent Compton scattering from the Helium-3 nucleus. We calculate $\\gamma ^3He$ elastic scattering observables using chiral perturbation theory to next-to-leading order (${\\mathcal O}(e^2 Q)$). We find that the unpolarized differential cross section can be used to measure neutron electric and magnetic polarizabilities, while two double-polarization observables are sensitive to different linear combinations of the four neutron spin polarizabilities.

Deepshikha Choudhury; Andreas Nogga; Daniel R. Phillips

2007-06-11T23:59:59.000Z

186

JOURNAL DE PHYSIQUE Colloque C6, supplkment au no 8, Tome 39, aofit 1978,page C6-1517 RECENT EXPERIMENTAL STUDIES OF DYNAMICS OF SPIN GLASSES  

E-Print Network [OSTI]

obtained with the help of esr, nmr, muon precession. Gssbauer effect and neutron scattering techniques& to study the onset of magnetic "ordering" in spin glass alloys /12-151. Neutron scattering techniques

Boyer, Edmond

187

Superconductivity Highlights | Neutron Science | ORNL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

188

On Hilbert after slide 4 1 echo $SHELL  

E-Print Network [OSTI]

On Hilbert after slide 4 1 echo $SHELL 2 ls ­la /bin/*sh* 3 clear 4 ls 5 cat get 6 ls ­la get after slide 5 1 cat Rb 2 cat rnorm.R 3 ./R 4 ls ­la Rb 5 chmod +x Rb 6 cat Rb 7 man ls 8 ls ­c *.out 9 ls ­lc *.out 10 man head 11 ./Rb rnorm.R 12 clear On Hilbert after slide 7 1 cat res 2 man

Dahl, David B.

189

Neutron Polarization  

Science Journals Connector (OSTI)

The production of polarized neutrons in magnetized iron has been studied, using the intense neutron beams available at the Argonne heavy water pile. The theoretical work of Halpern et al., used as a guide in the experiments, has been checked in many respects, with the exception that the polarization cross section p has a measured value of 3.15 barns compared to the theoretical 1 barn. The application of neutron polarization to the measurement of the approach to saturation in ferromagnets is described and preliminary results are reported.

D. J. Hughes; J. R. Wallace; R. H. Holtzman

1948-06-01T23:59:59.000Z

190

Pinpointing Chiral Structures with Front-Back Polarized Neutron Reflectometry  

Science Journals Connector (OSTI)

A new development in spin-polarized neutron reflectometry enables us to more fully characterize the nucleation and growth of buried domain walls in layered magnetic materials. We applied this technique to a thin-film exchange-spring magnet. After first measuring the reflectivity with the neutrons striking the front, we measure with the neutrons striking the back. Simultaneous fits are sensitive to the presence of spiral spin structures. The technique reveals previously unresolved features of field-dependent domain walls in exchange-spring systems and has sufficient generality to apply to a variety of magnetic systems.

K. V. O'Donovan; J. A. Borchers; C. F. Majkrzak; O. Hellwig; E. E. Fullerton

2002-01-25T23:59:59.000Z

191

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

192

Echo-Enabled Harmonic Generation for Seeded FELs  

SciTech Connect (OSTI)

In the x-ray wavelengths, the two leading FEL concepts are the self-amplified spontaneous emission (SASE) configuration and the high-gain harmonic generation (HGHG) scheme. While the radiation from a SASE FEL is coherent transversely, it typically has rather limited temporal coherence. Alternatively, the HGHG scheme allows generation of fully coherent radiation by up-converting the frequency of a high-power seed laser. However, due to the relatively low up-frequency conversion efficiency, multiple stages of HGHG FEL are needed in order to generate x-rays from a UV laser. The up-frequency conversion efficiency can be greatly improved with the recently proposed echo-enabled harmonic generation (EEHG) technique. In this work we will present the concept of EEHG, and address some practically important issues that affect the performance of the seeding. We show how the EEHG can be incorporated in the FEL scheme and what is the expected performance of the EEHG seeded FEL. We will then briefly describe the first proof-of-principle EEHG experiment carried out at the Next Linear Collider Test Accelerator (NLCTA) at SLAC. We will also discuss latest advances in the echo-scheme approach, and refer to subsequent modifications of the original concept.

Stupakov, G.; /SLAC

2011-05-19T23:59:59.000Z

193

Neutron Checkup  

Science Journals Connector (OSTI)

Neutron activation analysis is yet another technique in the arsenal of diagnostic methods that physicians can draw on to examine the health of their patients. The University of Washington's school of medicine in Seattle is the first facility in the ...

1969-11-10T23:59:59.000Z

194

Neutron Reflectometry  

Science Journals Connector (OSTI)

Neutron reflectometry is a relatively new technique [1,2]. In the last years, it has been extensively used for solving soft matter problems like polymer mixing [3,4] or the structure of liquids at the surface [5,

Claude Fermon; Frdric Ott; Alain Menelle

1999-01-01T23:59:59.000Z

195

Neutron Tomography and Space  

E-Print Network [OSTI]

Kevin Shields, Optimization of neutron tomography for rapidNEUTRON TOMOGRAPHY AND SPACE Hal Egbert, Ronald Walker, R.industrial applications[1]. Neutron Computed Tomography was

Egbert, Hal; Walker, Ronald; Flocchini, R.

2007-01-01T23:59:59.000Z

196

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

197

The maturity characterization of orange fruit by using high frequency ultrasonic echo pulse method  

E-Print Network [OSTI]

The maturity characterization of orange fruit by using high frequency ultrasonic echo pulse method of the maturity of orange fruit by the ultrasonic echo pulse method with immersion in water. This study relates the strong attenuation of the ultrasounds in the texture of fruits and vegetables, we limited our study only

Boyer, Edmond

198

SYSTEM IDENTIFICATION FOR MULTI-CHANNEL LISTENING-ROOM COMPENSATION USING AN ACOUSTIC ECHO CANCELLER  

E-Print Network [OSTI]

SYSTEM IDENTIFICATION FOR MULTI-CHANNEL LISTENING-ROOM COMPENSATION USING AN ACOUSTIC ECHO hands-free telecommunication devices jointly apply several subsystems, e.g. for noise reduction (NR), acoustic echo cancella- tion (AEC) and listening-room compensation (LRC). In this contri- bution

Lübeck, Universität zu

199

Correction of Physiologically Induced Global Off-Resonance Effects in Dynamic Echo-Planar and  

E-Print Network [OSTI]

information from the center of k-space and a navigator echo and is illustrated with dynamic scans of single oxygen level-dependant (BOLD) func- tional neuroimaging (3), which will be the primary focus of this work maps. Zero-order phase (non- evolving in time) corrections using navigator echoes (8­ 10

Glover, Gary H.

200

Dual-Doppler analysis of the 17 June 1997 bow echo over southeast Texas  

E-Print Network [OSTI]

not shown in conceptual models of bow echoes however is a distinct, smaller-scale, cyclonic vortex present along the northern front edge of the bow echo. This vortex seems to have formed from the tilting and subsequent stretching of vorticity generated...

Moncla, Kerry Louis

2012-06-07T23:59:59.000Z

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

A family of multiple sub-filters based acoustic echo cancellers  

Science Journals Connector (OSTI)

In this paper, a multiple sub-filter (MSF) approach is discussed in which, a single long filter (SLF) is partitioned into multiple subfilters to achieve fast convergence rate. The performance of the MSF parallel structure adaptation is studied for common ... Keywords: MSF, acoustic echo, adaptive filter, echo cancellation

Alaka Barik; Tarkeshwar P. Bhardwaj; Ravinder Nath

2010-12-01T23:59:59.000Z

202

ELECTRIC DIPOLAR ECHOES IN GLASSES L. BERNARD, L. PICHE, G. SCHUMACHER  

E-Print Network [OSTI]

field : we apply an R.F. electrical pulse to the electrodes attached on a thin disk of Suprasil I glassL-126 ELECTRIC DIPOLAR ECHOES IN GLASSES L. BERNARD, L. PICHE, G. SCHUMACHER C.R.T.B.T., C couplage avec les déformations élas- tiques. Abstract. 2014 Electric dipolar echoes are observed in OH

Boyer, Edmond

203

Centennial Variations of the Global Monsoon Precipitation in the Last Millennium: Results from ECHO-G Model  

E-Print Network [OSTI]

Centennial Variations of the Global Monsoon Precipitation in the Last Millennium: Results from ECHO-G with the ECHAM and the global Hamburg Ocean Primitive Equation (ECHO-G) coupled ocean­atmosphere model

Wang, Bin

204

JOURNAL DE PHYSIQUE Colloque C6, supplment au n 8, Tome 39, aot 1978, page C6-819 NEUTRON SCATTERING STUDY ON THE SPIN-FLOP SYSTEM Cs.MnBr3.2D20  

E-Print Network [OSTI]

JOURNAL DE PHYSIQUE Colloque C6, supplément au n° 8, Tome 39, août 1978, page C6-819 NEUTRON Netherlands Energy Research Foundation (ECN), Westerduinweg Z, 17SS LE Petten (NH) The Netherlands Department of Physios, Eindhoven University of Technology, Eindhoven, The Netherlands Résumé.- La variation de l

Paris-Sud XI, Université de

205

BPS Skyrmions as neutron stars  

E-Print Network [OSTI]

The BPS Skyrme model has been demonstrated already to provide a physically intriguing and quantitatively reliable description of nuclear matter. Indeed, the model has both the symmetries and the energy-momentum tensor of a perfect fluid, and thus represents a field theoretic realization of the "liquid droplet" model of nuclear matter. In addition, the classical soliton solutions together with some obvious corrections (spin-isospin quantization, Coulomb energy, proton-neutron mass difference) led to an accurate modeling of nuclear binding energies for heavier nuclei. These results lead to the rather obvious proposal to try to describe also neutron stars by the BPS Skyrme model coupled to gravity. We find that the resulting self-gravitating BPS Skyrmions provide an excellent description of neutron stars when the parameter values of the model are extracted from nuclear physics. Specifically, the maximum possible mass of a neutron star before black-hole formation sets in is a few solar masses, the precise value depending on the precise values of the model parameters, and the resulting neutron star radius is of the order of 10 km.

C. Adam; C. Naya; J. Sanchez-Guillen; R. Vazquez; A. Wereszczynski

2014-07-14T23:59:59.000Z

206

BPS Skyrmions as neutron stars  

E-Print Network [OSTI]

The BPS Skyrme model has been demonstrated already to provide a physically intriguing and quantitatively reliable description of nuclear matter. Indeed, the model has both the symmetries and the energy-momentum tensor of a perfect fluid, and thus represents a field theoretic realization of the "liquid droplet" model of nuclear matter. In addition, the classical soliton solutions together with some obvious corrections (spin-isospin quantization, Coulomb energy, proton-neutron mass difference) provide an accurate modeling of nuclear binding energies for heavier nuclei. These results lead to the rather natural proposal to try to describe also neutron stars by the BPS Skyrme model coupled to gravity. We find that the resulting self-gravitating BPS Skyrmions provide excellent results as well as some new perspectives for the description of bulk properties of neutron stars when the parameter values of the model are extracted from nuclear physics. Specifically, the maximum possible mass of a neutron star before black-hole formation sets in is a few solar masses, the precise value depending on the precise values of the model parameters, and the resulting neutron star radius is of the order of 10 km.

C. Adam; C. Naya; J. Sanchez-Guillen; R. Vazquez; A. Wereszczynski

2014-07-14T23:59:59.000Z

207

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

208

Parity Broken Chiral Spin Dynamics in Ba3NbFe3Si2O14 V. Simonet,1  

E-Print Network [OSTI]

by unpolarized and polarized inelastic neutron scattering. A dynamical fingerprint of the chiral ground state are equipopulated, the chirality is usually averaged to zero in centrosymmetric magnets. However, neutron scattering by means of polarized neutron scattering experiments. Our study provides evidence for a fully chiral spin

Boyer, Edmond

209

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

SciTech Connect (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

210

Megadroughts in Southwestern North America in ECHO-G Millennial Simulations and Their Comparison to Proxy Drought Reconstructions*  

E-Print Network [OSTI]

Megadroughts in Southwestern North America in ECHO-G Millennial Simulations and Their Comparison transient and control simulations from the ECHAM and the global Hamburg Ocean Primitive Equation (ECHO-G­42.58N, 1258­1058W). Megadroughts in the ECHO-G AOGCM are found to be similar in duration and magnitude

211

6.4 A BOW-ECHO EVENT ON A SQUALL LINE IN THE NETHERLANDS Rob Groenland  

E-Print Network [OSTI]

6.4 A BOW-ECHO EVENT ON A SQUALL LINE IN THE NETHERLANDS Rob Groenland Meteo Consult, Wageningen, The Netherlands (Europe) ABSTRACT In this study, the structure of a bow-echo on a squall line is investigated . It accelerated as it moved into the Netherlands. A bow-echo developed over extreme northern Belgium

Haak, Hein

212

Magnetic neutron scattering (invited)  

Science Journals Connector (OSTI)

The application of neutron scattering techniques to magnetic problems is reviewed. We will first discuss diffraction techniques used to solve magnetic structures as well as to measure magnetic form factors order parameters critical phenomena and the scattering from low?dimensional systems. We will also discuss inelastic scattering techniques including polarized beam methods utilized to determine the spin dynamics of various materials. Information will be provided about the types of spectrometers available at the user?oriented national facilities located at Argonne National Laboratory Brookhaven National Laboratory Los Alamos National Laboratory The National Institute of Standards and Technology and Oak Ridge National Laboratory as well as the spectrometers at the Missouri University Research Reactor.

J. W. Lynn

1994-01-01T23:59:59.000Z

213

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

214

Fast-Neutron Handbook  

Science Journals Connector (OSTI)

... FAST neutron physics, in the present context, concerns the study of interactions of atomic nuclei with neutrons ...

J. H. MONTAGUE

1961-06-10T23:59:59.000Z

215

EChO Payload electronics architecture and SW design  

E-Print Network [OSTI]

EChO is a three-modules (VNIR, SWIR, MWIR), highly integrated spectrometer, covering the wavelength range from 0.55 $\\mu$m, to 11.0 $\\mu$m. The baseline design includes the goal wavelength extension to 0.4 $\\mu$m while an optional LWIR module extends the range to the goal wavelength of 16.0 $\\mu$m. An Instrument Control Unit (ICU) is foreseen as the main electronic subsystem interfacing the spacecraft and collecting data from all the payload spectrometers modules. ICU is in charge of two main tasks: the overall payload control (Instrument Control Function) and the housekeepings and scientific data digital processing (Data Processing Function), including the lossless compression prior to store the science data to the Solid State Mass Memory of the Spacecraft. These two main tasks are accomplished thanks to the Payload On Board Software (P-OBSW) running on the ICU CPUs.

Focardi, M; Farina, M; Pancrazzi, M; Ottensamer, R; Lim, T L; Pezzuto, S; Micela, G; Pace, E

2014-01-01T23:59:59.000Z

216

Neutron Interactions: Q-Equation, Elastic Scattering  

E-Print Network [OSTI]

Since a neutron has no charge it can easily enter into a nucleus and cause a reaction. Neutrons interact primarily with the nucleus of an atom, except in the special case of magnetic scattering where the interaction involves the neutron spin and the magnetic moment of the atom. Because magnetic scattering is of no interest in this class, we can neglect the interaction between neutrons and electrons and think of atoms and nuclei interchangeably. Neutron reactions can take place at any energy, so one has to pay particular attention to the energy variation of the interaction cross section. In a nuclear reactor neutrons can have energies ranging from 10-3 ev (1 mev) to 10 7 ev (10 Mev). This means our study of neutron interactions, in principle, will have to cover an energy range of 10 ten orders of magnitude. In practice we will limit ourselves to two energy ranges, the slowing down region (ev to Kev) and the thermal region (around 0.025 ev). For a given energy region thermal, epithermal, resonance, fast not all the possible reactions are equally important. Which reaction is important depends on the target nucleus and the neutron energy. Generally speaking the important types of interactions, in the order of increasing complexity from the standpoint of theoretical

unknown authors

217

Neutron Scattering User Program | Neutron Science | ORNL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

User Program SHARE Neutron Scattering Can Benefit Your Research Neutron scattering has applications in almost every technical and scientific field, from biology and chemistry to...

218

Neutron Polarization  

Science Journals Connector (OSTI)

Experiments for the determination of the polarization cross section p of iron with monochromatic and non-monochromatic neutrons are described. The absolute value of p as well as its dependence on the neutron velocity is found to be in good agreement with the recent calculations of Steinberger and Wick and also with other experiments. For a complex neutron spectrum originating from a paraffin moderator p is found to be (2.350.1)10-24 cm2 in agreement with previous investigations. It is shown that the larger value of 3.1510-24 cm2 found by Hughes, Wallace, and Holtzman must be due to spectral differences. The approach of the magnetization of iron towards saturation is also investigated.

J. Fleeman; D. B. Nicodemus; H. H. Staub

1949-12-15T23:59:59.000Z

219

The breaking strain of neutron star crust  

SciTech Connect (OSTI)

Mountains on rapidly rotating neutron stars efficiently radiate gravitational waves. The maximum possible size of these mountains depends on the breaking strain of neutron star crust. With multimillion ion molecular dynamics simulations of Coulomb solids representing the crust, we show that the breaking strain of pure single crystals is very large and that impurities, defects, and grain boundaries only modestly reduce the breaking strain to around 0.1. Due to the collective behavior of the ions during failure found in our simulations, the neutron star crust is likely very strong and can support mountains large enough so that their gTavitational wave radiation could limit the spin periods of some stars and might be detectable in large scale interferometers. Furthermore, our microscopic modeling of neutron star crust material can help analyze mechanisms relevant in Magnetar Giant and Micro Flares.

Kadau, Kai [Los Alamos National Laboratory; Horowitz, C J [INDIANA UNIV

2009-01-01T23:59:59.000Z

220

The Neutron  

Science Journals Connector (OSTI)

The writers point out that the postulation of the existence of the "neutron," a combination of an electron and a proton, of small size and low energy would be very useful in explaining a number of atomic and cosmic phenomena. They find that a mathematical treatment based on existing theory leads to indications of such a state but no definite proof.

R. M. Langer and N. Rosen

1931-06-15T23:59:59.000Z

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.


221

The helical jet of IGR J11014-6103: echoes of a core-collapse supernova  

E-Print Network [OSTI]

Jets from rotation-powered pulsars have so far only been observed in systems moving subsonically trough their ambient medium and/or embedded in their progenitor supernova remnant (SNR). Supersonic runaway pulsars are also expected to produce jets, but they have not been confirmed so far. We investigated the nature of the jet-like structure associated to the INTEGRAL source IGR J11014-6103. The source is a neutron star escaping its parent SNR MSH 11-61A supersonically at a velocity exceeding 1000 km/s. We observed IGR J11014-6103 and its jet-like X-ray structure through dedicated high spatial resolution observations in X-rays (Chandra) and radio band (ATCA). Our results show that the feature is a true pulsar's jet. It extends highly collimated over 11pc, displays a clear precession-like modulation, and propagates nearly perpendicular to the system direction of motion, implying that the neutron star's spin axis in IGR J11014-6103 is almost perpendicular to the direction of the kick received during the supernova...

Pavan, L; Puehlhofer, G; Filipovic, M D; De Horta, A; O'Brien, A; Balbo, M; Walter, R; Bozzo, E; Ferrigno, C; Crawford, E; Stella, L

2013-01-01T23:59:59.000Z

222

On the Neutron-Proton Interaction  

Science Journals Connector (OSTI)

Field theories of nuclear forces predict the existence of a spin dependent interaction similar in character to the coupling energy between two dipoles. The purpose of this paper is to study the influence of such spin-spin forces on the behavior of the neutron-proton system. A phenomenological theory is developed in which are adopted simplified rectangular well potentials whose constants are determined to fit the binding energy and quadripole moment of the deuteron, and the scattering of slow neutrons in hydrogen. The range of the forces is chosen to be that deduced from proton-proton scattering. The effects investigated include the magnetic moment of the deuteron, the scattering of neutrons in hydrogen, the radiative capture of slow neutrons, and the photo-disintegration of the deuteron. Most of the effects considered can be understood as a simple consequence of the reduced amount of the S13 ground state of the deuteron occasioned by the admixture of a small percentage of a D13 state. The phenomenological theory here employed adequately represents the experimental data, with the exception of the photomagnetic disintegration of the deuteron which would seem to require a detailed knowledge of the charge-bearing field.

William Rarita and Julian Schwinger

1941-03-01T23:59:59.000Z

223

NEUTRON ELECTRIC-DIPOLE MOMENT, ULTRACOLD NEUTRONS  

E-Print Network [OSTI]

NEUTRON ELECTRIC-DIPOLE MOMENT, ULTRACOLD NEUTRONS AND POLARIZED 3He R. GOLUB~and Steve K REPORTS (Review Section of Physics Letters) 237, No. 1(1994)1--62. PHYSICS REPORTS North-Holland Neutron electric-dipole moment, ultracold neutrons and polarized 3He R. Goluba and Steve K. Lamoreauxb a

224

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

225

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

226

Spin structure in high energy processes: Proceedings  

SciTech Connect (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

227

SmartPower Spreading Energy Efficiency to Echo-boomers | Department of  

Broader source: Energy.gov (indexed) [DOE]

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

228

SmartPower Spreading Energy Efficiency to Echo-boomers | Department of  

Broader source: Energy.gov (indexed) [DOE]

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

229

The phase 0/A study of the ESA M3 mission candidate EChO  

Science Journals Connector (OSTI)

EChO, the Exoplanet Characterisation Observatory, has been one of the five M-class mission candidates competing for the M3 launch slot within the science programme Cosmic Vision 20152025 of the European Space...

Ludovic Puig; Kate Isaak; Martin Linder; Isabel Escudero

2014-10-01T23:59:59.000Z

230

Impossibility of faithfully storing single photons with the three-pulse photon echo  

SciTech Connect (OSTI)

The three-pulse photon echo is a well-known technique to store intense light pulses in an inhomogeneously broadened atomic ensemble. This protocol is attractive because it is relatively simple and it is well suited for the storage of multiple temporal modes. Furthermore, it offers very long storage times, greater than the phase relaxation time. Here, we consider the three-pulse photon echo in both two- and three-level systems as a potential technique for the storage of light at the single-photon level. By explicit calculations, we show that the ratio between the echo signal corresponding to a single-photon input and the noise is smaller than one. This severely limits the achievable fidelity of the quantum state storage, making the three-pulse photon echo unsuitable for single-photon quantum memory.

Sangouard, Nicolas; Minar, Jiri; Afzelius, Mikael; Gisin, Nicolas; Riedmatten, Hugues de [Group of Applied Physics, University of Geneva, Geneva (Switzerland); Simon, Christoph; Tittel, Wolfgang [Institute for Quantum Information Science and Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); Chaneliere, Thierry; Le Goueet, Jean-Louis [Laboratoire Aime Cotton, CNRS-UPR 3321, Universite Paris-Sud, F-91405 Orsay cedex (France)

2010-06-15T23:59:59.000Z

231

Broadband and statistical characterization of echoes from random scatterers : application to acoustic scattering by marine organisms  

E-Print Network [OSTI]

The interpretation of echoes collected by active remote-sensing systems, such as sonar and radar, is often ambiguous due to the complexities in the scattering processes involving the scatterers, the environment, and the ...

Lee, Wu-Jung

2013-01-01T23:59:59.000Z

232

The Theory of Three-level Photon Echo Using of Rotating Wave Approximation  

E-Print Network [OSTI]

The three level photon echo has been described in different works by using rotating wave approximation but none of them did not get results which show the effects of field's frequencies on frequency of ground level of system. In this work, we studied a Lambda type system theoretically and numerically. By considering the Doppler effect in environment, we get different equation for polarization of echo signal and its intensity.

Tara Ahmadi; Sergei. A Pulkin; Vladimir. A Sheftsov

2014-05-29T23:59:59.000Z

233

PROBING INTERSTELLAR DUST WITH INFRARED ECHOES FROM THE Cas A SUPERNOVA  

SciTech Connect (OSTI)

We present the analysis of an Infrared Spectrograph 5-38 {mu}m spectrum and Multiband Imaging Photometer for Spitzer photometric measurements of an infrared echo near the Cassiopeia A (Cas A) supernova (SN) remnant observed with the Spitzer Space Telescope. We have modeled the recorded echo accounting for polycyclic aromatic hydrocarbons (PAHs), quantum-heated carbon and silicate grains, as well as thermal carbon and silicate particles. Using the fact that optical light-echo spectroscopy has established that Cas A originated from a Type IIb SN explosion showing an optical spectrum remarkably similar to the prototypical Type IIb SN 1993J, we use the latter to construct template data input for our simulations. We are then able to reproduce the recorded infrared echo spectrum by combining the emission of dust heated by the UV burst produced at the shock breakout after the core-collapse and dust heated by optical light emitted near the visual maximum of the SN light curve, where the UV burst and optical light curve characteristics are based on SN 1993J. We find a mean density of {approx}680 H cm{sup -3} for the echo region, with a size of a few light years across. We also find evidence of dust processing in the form of a lack of small PAHs with less than {approx}300 carbon atoms, consistent with a scenario of PAHs destruction by the UV burst via photodissociation at the estimated distance of the echo region from Cas A. Furthermore, our simulations suggest that the weak 11 {mu}m features of our recorded infrared echo spectrum are consistent with a strong dehydrogenated state of the PAHs. This exploratory study highlights the potential of investigating dust processing in the interstellar medium through infrared echoes.

Vogt, Frederic P. A. [Mount Stromlo Observatory, Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Besel, Marc-Andre; Krause, Oliver; Dullemond, Cornelis P., E-mail: fvogt@mso.anu.edu.au [Max-Planck Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany)

2012-05-10T23:59:59.000Z

234

Neutron Scattering Facilities 1982  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

235

RHIC | Spin Physics  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

236

Lambda-Neutron Scattering Lengths from Radiative K-minus Capture  

E-Print Network [OSTI]

Radiative capture of the K-minus by the deuteron as a reaction for measurement of the Lambda-neutron scattering lengths. The use of spin information to separate the singlet and triplet scattering lengths is treated.

W. R. Gibbs; S. A. Coon; H. K. Han; B. F. Gibson

2000-01-02T23:59:59.000Z

237

Noise pair velocity and range echo location system  

DOE Patents [OSTI]

An echo-location method for microwaves, sound and light capable of using incoherent and arbitrary waveforms of wide bandwidth to measure velocity and range (and target size) simultaneously to high resolution. Two interferometers having very long and nearly equal delays are used in series with the target interposed. The delays can be longer than the target range of interest. The first interferometer imprints a partial coherence on an initially incoherent source which allows autocorrelation to be performed on the reflected signal to determine velocity. A coherent cross-correlation subsequent to the second interferometer with the source determines a velocity discriminated range. Dithering the second interferometer identifies portions of the cross-correlation belonging to a target apart from clutter moving at a different velocity. The velocity discrimination is insensitive to all slowly varying distortions in the signal path. Speckle in the image of target and antenna lobing due to parasitic reflections is minimal for an incoherent source. An arbitrary source which varies its spectrum dramatically and randomly from pulse to pulse creates a radar elusive to jamming. Monochromatic sources which jigger in frequency from pulse to pulse or combinations of monochromatic sources can simulate some benefits of incoherent broadband sources. Clutter which has a symmetrical velocity spectrum will self-cancel for short wavelengths, such as the apparent motion of ground surrounding target from a sidelooking airborne antenna.

Erskine, David J. (Oakland, CA)

1999-01-01T23:59:59.000Z

238

Noise pair velocity and range echo location system  

DOE Patents [OSTI]

An echo-location method for microwaves, sound and light capable of using incoherent and arbitrary waveforms of wide bandwidth to measure velocity and range (and target size) simultaneously to high resolution is disclosed. Two interferometers having very long and nearly equal delays are used in series with the target interposed. The delays can be longer than the target range of interest. The first interferometer imprints a partial coherence on an initially incoherent source which allows autocorrelation to be performed on the reflected signal to determine velocity. A coherent cross-correlation subsequent to the second interferometer with the source determines a velocity discriminated range. Dithering the second interferometer identifies portions of the cross-correlation belonging to a target apart from clutter moving at a different velocity. The velocity discrimination is insensitive to all slowly varying distortions in the signal path. Speckle in the image of target and antenna lobing due to parasitic reflections is minimal for an incoherent source. An arbitrary source which varies its spectrum dramatically and randomly from pulse to pulse creates a radar elusive to jamming. Monochromatic sources which jigger in frequency from pulse to pulse or combinations of monochromatic sources can simulate some benefits of incoherent broadband sources. Clutter which has a symmetrical velocity spectrum will self-cancel for short wavelengths, such as the apparent motion of ground surrounding target from a sidelooking airborne antenna. 46 figs.

Erskine, D.J.

1999-02-16T23:59:59.000Z

239

Neutron Polarization  

Science Journals Connector (OSTI)

The neutron polarization cross section of iron has been measured as a function of energy from 0.7 to 3.3A by two methods: using the single transmission effect in a block of polycrystalline iron at energies selected by a quartz crystal monochromator; and using a single crystal of magnetized magnetite to analyze the beam emerging from the iron polarizer, the magnetite crystal itself serving as monochromator. The measured values are compared with those of other observers and the theoretically expected values. These are found to agree fairly well within the limits of accuracy of the measurements and existing knowledge of the wave function of the iron 3d shell. The two techniques were used also to determine the average polarization (32 percent) as seen by a 1v detector in a beam of reactor neutrons emerging from a 4-cm thick polarizing block of iron. Problems and techniques associated with the measurement of the average polarization of a continuous spectrum are discussed. A simplified experimental treatment of the problem of beam "hardening" is described. A description is given of the use of the magnetic resonance method in conjunction with a single-crystal magnetite analyzer for the measurement of neutron polarization.

C. P. Stanford; T. E. Stephenson; L. W. Cochran; S. Bernstein

1954-04-15T23:59:59.000Z

240

Neutron Gas  

Science Journals Connector (OSTI)

We assume that the neutron-neutron potential is well-behaved and velocity-dependent. We can then apply perturbation theory to find the energy per particle of a neutron gas, in the range of Fermi wave numbers 0.5

J. S. Levinger and L. M. Simmons

1961-11-01T23:59:59.000Z

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.


241

The determination of the in situ structure by nuclear spin contrast variation  

SciTech Connect (OSTI)

Polarized neutron scattering from polarized nuclear spins in hydrogenous substances opens a new way of contrast variation. The enhanced contrast due to proton spin polarization was used for the in situ structure determination of tRNA of the functional complex of the E.coli ribosome.

Stuhrmann, H.B. [GKSS Forschungszentrum, Geesthacht (Germany); Nierhaus, K.H. [Max-Planch-Institut fuer Molekulare Genetik, Berlin (Germany)

1994-12-31T23:59:59.000Z

242

Jefferson Lab's results on the Q^2-evolution of moments of spin structure functions  

E-Print Network [OSTI]

We present the recent JLab measurements on moments of spin structure functions at intermediate and low Q^2. The Bjorken sum and Burkhardt-Cottingham sum on the neutron are presented. The later appears to hold. Higher moments (generalized spin polarizabilities and d_2^n) are shown and compared to chiral perturbation theory and lattice QCD respectively.

A. Deur

2005-07-15T23:59:59.000Z

243

Isolated electron spins in silicon carbide with millisecond-coherence times  

E-Print Network [OSTI]

The elimination of defects from SiC has facilitated its move to the forefront of the optoelectronics and power-electronics industries. Nonetheless, because the electronic states of SiC defects can have sharp optical and spin transitions, they are increasingly recognized as a valuable resource for quantum-information and nanoscale-sensing applications. Here, we show that individual electron spin states in highly purified monocrystalline 4H-SiC can be isolated and coherently controlled. Bound to neutral divacancy defects, these states exhibit exceptionally long ensemble Hahn-echo spin coherence, exceeding 1 ms. Coherent control of single spins in a material amenable to advanced growth and microfabrication techniques is an exciting route to wafer-scale quantum technologies.

David J. Christle; Abram L. Falk; Paolo Andrich; Paul V. Klimov; Jawad ul Hassan; Nguyen T. Son; Erik Janzn; Takeshi Ohshima; David D. Awschalom

2014-06-27T23:59:59.000Z

244

Equivalence principle and experimental tests of gravitational spin effects  

SciTech Connect (OSTI)

We study the possibility of experimentally testing the manifestations of the equivalence principle in spin-gravity interactions. We reconsider the earlier experimental data and get the first experimental bound on the anomalous gravitomagnetic moment. The spin coupling to the Earth's rotation may also be explored at the extensions of neutron electric-dipole-moment and g-2 experiments. The spin coupling to terrestrial gravity produces a considerable effect which may be discovered at the planned deuteron electric-dipole-moment experiment. The Earth's rotation should also be taken into account in optical experiments in search of axionlike particles.

Silenko, Alexander J.; Teryaev, Oleg V. [Institute of Nuclear Problems, Belarusian State University, Minsk 220080 (Belarus); Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation)

2007-09-15T23:59:59.000Z

245

New Results on Nucleon Spin Structure  

E-Print Network [OSTI]

Recent precision spin structure data from Jefferson Lab have significantly advanced our knowledge of nucleon structure in the valence quark (high-$x$) region and improved our understanding of higher-twist effects, spin sum rules and quark-hadron duality. First, results of a precision measurement of the neutron spin asymmetry, $A_1^n$, in the high-$x$ region are discussed. The new data shows that $A_1^n$ becomes positive at high $x$. They provide crucial input for the global fits to world data to extract polarized parton distribution functions. The up and down quark spin distributions in the nucleon were extracted. The results for $\\Delta d/d$ disagree with the leading-order pQCD prediction assuming hadron helicity conservation. Then, results of a precision measurement of the $g_2^n$ structure function to study higher-twist effects are presented. The data show a clear deviation from the lead-twist contribution. The second moment of the spin structure functions and the twist-3 matrix element $d_2^n$ results were extracted at a high $Q2$ of 5 GeV$^2$. Results for $d_2^n$ at low-to-intermediate $Q2$ from 0.1 to 0.9 GeV$^2$ were also extracted from the JLab data. In the same $Q2$ range, the $Q2$ dependence of the moments of the nucleon spin structure functions was measured, providing a unique bridge linking the quark-gluon picture of the nucleon and the coherent hadronic picture. Sum rules and generalized forward spin polarizabilities were extracted. Finally, preliminary results were presented on the resonance spin structure functions in the $Q2$ range from 1 to 4 GeV$^2$ to study the quark-hadron duality.

Jian-ping Chen

2005-11-21T23:59:59.000Z

246

Short Gamma-Ray Bursts from Binary Neutron Star Mergers  

E-Print Network [OSTI]

We present the results from new relativistic hydrodynamic simulations of binary neutron star mergers using realistic non-zero temperature equations of state. We vary several unknown parameters in the system such as the neutron star (NS) masses, their spins and the nuclear equation of state. The results are then investigated with special focus on the post-merger torus-remnant system. Observational implications on the Gamma-ray burst (GRB) energetics are discussed and compared with recent observations.

Roland Oechslin; Thomas Janka

2006-04-27T23:59:59.000Z

247

Publications | Neutron Science | ORNL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Publications SHARE Publications The Neutron Science publications system contains peer-reviewed publications based on research conducted at ORNL's Neutron Science facilities or...

248

Neutron Scattering Facilities  

Science Journals Connector (OSTI)

The past history, present performance and future prospects for neutron scattering facilities will be discussed. Special features of neutron scattering techniques applicable to biological problems will be ... . Th...

D. L. Price

1996-01-01T23:59:59.000Z

249

Possible Effects of Pair Echoes on Gamma-Ray Burst Afterglow Emission  

E-Print Network [OSTI]

High-energy emission from gamma-ray bursts (GRBs) is widely expected but had been sparsely observed until recently when the Fermi satellite was launched. If >TeV gamma rays are produced in GRBs and can escape from the emission region, they are attenuated by the cosmic infrared background photons, leading to regeneration of GeV-TeV secondary photons via inverse-Compton scattering. This secondary emission can last for a longer time than the duration of GRBs, and it is called a pair echo. We investigate how this pair echo emission affects spectra and light curves of high energy afterglows, considering not only prompt emission but also afterglow as the primary emission. Detection of pair echoes is possible as long as the intergalactic magnetic field (IGMF) in voids is weak. We find (1) that the pair echo from the primary afterglow emission can affect the observed high-energy emission in the afterglow phase after the jet break, and (2) that the pair echo from the primary prompt emission can also be relevant, but only when significant energy is emitted in the TeV range, typically E_{gamma, >0.1 TeV} > (Y/(1+Y)) epsilon_e E_k. Even non-detections of the pair echoes could place interesting constraints on the strength of IGMF. The more favorable targets to detect pair echoes may be the "naked" GRBs without conventional afterglow emission, although energetic naked GRBs would be rare. If the IGMF is weak enough, it is predicted that the GeV emission extends to >30-300 s.

Kohta Murase; Bing Zhang; Keitaro Takahashi; Shigehiro Nagataki

2009-02-27T23:59:59.000Z

250

Calculations of neutron spectra after neutronneutron scattering  

Science Journals Connector (OSTI)

A direct neutronneutron scattering length, ann, measurement with the goal of 3% accuracy (0.5 fm) is under preparation at the aperiodic pulsed reactor YAGUAR. A direct measurement of ann will not only help resolve conflicting results of ann by indirect means, but also in comparison to the protonproton scattering length, app, shed light on the charge-symmetry of the nuclear force. We discuss in detail the analysis of the nn-scattering data in terms of a simple analytical expression. We also discuss calibration measurements using the time-of-flight spectra of neutrons scattered on He and Ar gases and the neutron activation technique. In particular, we calculate the neutron velocity and time-of-flight spectra after scattering neutrons on neutrons and after scattering neutrons on He and Ar atoms for the proposed experimental geometry, using a realistic neutron flux spectrumMaxwellian plus epithermal tail. The shape of the neutron spectrum after scattering is appreciably different from the initial spectrum, due to collisions between thermalthermal and thermalepithermal neutrons. At the same time, the integral over the Maxwellian part of the realistic scattering spectrum differs by only about 6 per cent from that of a pure Maxwellian nn-scattering spectrum.

B E Crawford; S L Stephenson; C R Howell; G E Mitchell; W Tornow; W I Furman; E V Lychagin; A Yu Muzichka; G V Nekhaev; A V Strelkov; E I Sharapov; V N Shvetsov

2004-01-01T23:59:59.000Z

251

Spallation Neutron Source | ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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...

252

Precision Measurement of PArity Violation in Polarized Cold Neutron Capture on the Proton: the NPDGamma Experiment  

E-Print Network [OSTI]

The NPDGamma experiment at the Los Alamos Neutron Science Center (LANSCE) is dedicated to measure with high precision the parity violating asymmetry in the $\\gamma$ emission after capture of spin polarized cold neutrons in para-hydrogen. The measurement will determine unambiguously the weak pion-nucleon-nucleon ($\\pi NN$) coupling constant {\\it f$^1_{\\pi}$}

Lauss Bernhard

2006-01-02T23:59:59.000Z

253

Mantid - Data Analysis and Visualization Package for Neutron Scattering and $\\mu SR$ Experiments  

E-Print Network [OSTI]

The Mantid framework is a software solution developed for the analysis and visualization of neutron scattering and muon spin measurements. The framework is jointly developed by software engineers and scientists at the ISIS Neutron and Muon Facility and the Oak Ridge National Laboratory. The objectives, functionality and novel design aspects of Mantid are described.

Arnold, O; Borreguero, J M; Buts, A; Campbell, S I; Chapon, L; Doucet, M; Draper, N; Leal, R Ferraz; Gigg, M A; Lynch, V E; Markvardsen, A; Mikkelson, D J; Mikkelson, R L; Miller, R; Palmen, K; Parker, P; Passos, G; Perring, T G; Peterson, P F; Ren, S; Reuter, M A; Savici, A T; Taylor, J W; Taylor, R J; Tolchenov, R; Zhou, W; Zikovsky, J

2014-01-01T23:59:59.000Z

254

Quasiuniversal properties of neutron star mergers  

E-Print Network [OSTI]

Binary neutron star mergers are studied using nonlinear 3+1 numerical relativity simulations and the analytical effective-one-body (EOB) model. The EOB model predicts quasiuniversal relations between the mass-rescaled gravitational wave frequency and the binding energy at the moment of merger, and certain dimensionless binary tidal coupling constants depending on the stars Love numbers, compactnesses and the binary mass ratio. These relations are quasiuniversal in the sense that, for a given value of the tidal coupling constant, they depend significantly neither on the equation of state nor on the mass ratio, though they do depend on stars spins. The spin dependence is approximately linear for small spins aligned with the orbital angular momentum. The quasiuniversality is a property of the conservative dynamics; nontrivial relations emerge as the binary interaction becomes tidally dominated. This analytical prediction is qualitatively consistent with new, multi-orbit numerical relativity results for the relevant case of equal-mass irrotational binaries. Universal relations are thus expected to characterize neutron star mergers dynamics. In the context of gravitational wave astronomy, these universal relations may be used to constrain the neutron star equation of state using waveforms that model the merger accurately.

Sebastiano Bernuzzi; Alessandro Nagar; Simone Balmelli; Tim Dietrich; Maximiliano Ujevic

2014-02-25T23:59:59.000Z

255

Science | ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

256

Neutron lifetime measured with stored ultracold neutrons  

Science Journals Connector (OSTI)

The neutron lifetime has been measured by counting the neutrons remaining in a fluid-walled bottle as a function of the duration of storage. Losses of neutrons caused by the wall reflections are eliminated by varying the bottle volume-to-surface ratio. The result obtained is ??=887.63 s.

W. Mampe; P. Ageron; C. Bates; J. M. Pendlebury; A. Steyerl

1989-08-07T23:59:59.000Z

257

Neutron Compound Refractive Prisms - DOE SBIR Phase II Final Report  

SciTech Connect (OSTI)

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

258

Neutron-Neutron Quasifree Scattering  

Science Journals Connector (OSTI)

The reaction D(n ,2n)p has been measured at Einc=14.1 MeV, ?n (3)=?n(4)=30?, ?=180?, and the results are compared with the predictions of two separable-potential models. Neutron-proton and proton-proton quasifree scattering from nucleon + deuteron reactions at 14 MeV are also compared with the predictions of the same models. The upper limit of 2 mb/sr2 is determined for the reaction D(n,n?)d.

Ivo Slaus; J. W. Sunier; G. Thompson; J. C. Young; J. W. Verba; D. J. Margaziotis; P. Doherty; R. T. Cahill

1971-03-29T23:59:59.000Z

259

Application of off-specular polarized neutron reflectometry to measurements on an array of mesoscopic ferromagnetic disks  

SciTech Connect (OSTI)

Using off-specular polarized neutron reflectometry with neutron spin analysis, we determined the magnetic properties of a large array of in-plane magnetized ferromagnetic Co disks. Resonant peaks are clearly observed in the off-specular reflectivity, due to the lateral periodicity of the disk array. Using polarized neutrons, the intensity of the resonant peak in the off-specular reflectivity is studied as a function of the magnetic field applied in the sample plane. Spin analysis of the reflected neutrons reveals the magnetization reversal and saturation within the disks. {copyright} 2001 American Institute of Physics.

Temst, K.; Van Bael, M. J.; Fritzsche, H.

2001-08-13T23:59:59.000Z

260

Scattered-Light Echoes from the Historical Galactic Supernovae Cassiopeia A and Tycho (SN 1572)  

SciTech Connect (OSTI)

We report the discovery of an extensive system of scattered light echo arclets associated with the recent supernovae in the local neighborhood of the Milky Way: Tycho (SN 1572) and Cassiopeia A. Existing work suggests that the Tycho SN was a thermonuclear explosion while the Cas A supernova was a core collapse explosion. Precise classifications according to modern nomenclature require spectra of the outburst light. In the case of ancient SNe, this can only be done with spectroscopy of their light echo, where the discovery of the light echoes from the outburst light is the first step. Adjacent light echo positions suggest that Cas A and Tycho may share common scattering dust structures. If so, it is possible to measure precise distances between historical Galactic supernovae. On-going surveys that alert on the development of bright scattered-light echo features have the potential to reveal detailed spectroscopic information for many recent Galactic supernovae, both directly visible and obscured by dust in the Galactic plane.

Rest, A; Welch, D L; Suntzeff, N B; Oaster, L; Lanning, H; Olsen, K; Smith, R C; Becker, A C; Bergmann, M; Challis, P; Clocchiatti, A; Cook, K H; Damke, G; Garg, A; Huber, M E; Matheson, T; Minniti, D; Prieto, J L; Wood-Vasey, W M

2008-05-06T23:59:59.000Z

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

A molecular cloud within the light echo of V838 Monocerotis  

E-Print Network [OSTI]

Context. V838 Mon is an eruptive variable, which exploded in 2002. It displayed the most spectacular light echo ever observed. However, neither the origin of the reflecting matter nor the nature of the 2002 outburst have been firmly constrained. Aims. We investigate the nature of the CO radio emission detected in the field of the light echo. In particular, we explore its connection to the echoing dust around V838 Mon. Methods. We observed the echo region in multiple CO rotational transitions. We present and analyse maps of the region obtained in the 12CO(1-0) and (3-2) lines. In addition, deep spectra at several positions were acquired in 12CO(1-0), (2-1), (3-2), and 13CO(1-0), (2-1). Radiative transfer modelling of line intensities is performed for chosen positions to constrain the kinetic temperatures and densities. We derive global parameters (e.g. mass, distance, total column density) of the emitting cloud. Results. We found that a compact molecular cloud is located within the echo region. The molecular e...

Kami?ski, T; Deguchi, S

2011-01-01T23:59:59.000Z

262

Asymmetry in the Outburst of SN 1987A Detected Using Light Echo Spectroscopy  

E-Print Network [OSTI]

We report direct evidence for asymmetry in the early phases of SN 1987A via optical spectroscopy of five fields of its light echo system. The light echoes allow the first few hundred days of the explosion to be reobserved, with different position angles providing different viewing angles to the supernova. Light echo spectroscopy therefore allows a direct spectroscopic comparison of light originating from different regions of the photosphere during the early phases of SN 1987A. Gemini multi-object spectroscopy of the light echo fields shows fine-structure in the H-alpha line as a smooth function of position angle on the near-circular light echo rings. H-alpha profiles originating from the northern hemisphere of SN 1987A show an excess in redshifted emission and a blue knee, while southern hemisphere profiles show an excess of blueshifted H-alpha emission and a red knee. This fine-structure is reminiscent of the "Bochum event" originally observed for SN 1987A, but in an exaggerated form. Maximum deviation from ...

Sinnott, B; Rest, A; Sutherland, P G; Bergmann, M

2012-01-01T23:59:59.000Z

263

The Scattering of Neutrons by Ortho- and Parahydrogen  

Science Journals Connector (OSTI)

Calculations have been performed which indicate that experiments on the scattering of neutrons by ortho- and parahydrogen would enable one to determine the sign of the singlet state binding energy and the range of the neutron-proton interaction, in addition to providing direct information concerning the spin dependence of the neutron-proton interaction. A dependence of the neutron-proton interaction upon the relative spin orientation of the particles will manifest itself in a marked difference between the slow neutron scattering cross sections of orthohydrogen (parallel proton spins) and parahydrogen (anti-parallel proton spins). Neutrons with energy less than 0.068 ev, incident upon para-H2 in its ground state (J=0,v=0,S=0), may be either elastically scattered, or inelastically scattered with excitation of the molecule to the ground state of the ortho system (J=1,v=0,S=1). This latter process, requiring 0.023 ev, occurs only if the neutron-proton interaction is spin dependent. When the neutron energy is less than 0.045 ev, the cross section for the scattering of neutrons by ortho-H2 in its ground state will be the sum of the elastic scattering cross section and the cross section for the inelastic process in which the molecule is converted to a para-H2 molecule in its ground state, with the neutron taking up the excess energy. The cross sections of these four processes have been calculated, assuming an interaction range of 210-13 cm and a virtual singlet state of the deuteron. For liquid-air temperature neutrons (3kT2=0.012 ev), ?para(0.012)=0.2110-24 cm2, while ?ortho(0.012)=6510-24 cm2. The cross sections for neutrons at ordinary temperatures (3kT2=0.037 ev), however, are ?para(0.037)=1910-24 cm2, and ?ortho(0.037)=5010-24 cm2. Therefore, if the present concept of the neutron-proton interaction is valid, one would expect the following results: (a) The ortho-scattering cross section for liquid air neutrons should be about 300 times the corresponding para-scattering cross section. (b) The para-scattering cross section for ordinary thermal neutrons should be roughly 100 times the para-scattering cross section for liquid air neutrons. For a real singlet state, however, these ratios are of the order of one. The elastic para-scattering cross section is quite sensitive to the value of the range of interaction if the singlet state is virtual. For example, the value of this cross section at liquid air neutron temperatures with zero range of interaction is 1.7510-24 cm2, as compared with 0.2610-24 cm2 for an interaction range of 210-13 cm. Hence, from a measurement of the para elastic scattering cross section for homogeneous neutrons at some energy less than 0.023 ev, the range of interaction in the triplet state may be inferred with some degree of accuracy. A discussion of the influence of intermolecular forces on the previous results is given.

Julian Schwinger and E. Teller

1937-08-15T23:59:59.000Z

264

Versatile module for experiments with focussing neutron guides  

E-Print Network [OSTI]

We report the development of a versatile module that permits fast and reliable use of focussing neutron guides under varying scattering angles. A simple procedure for setting up the module and neutron guides is illustrated by typical intensity patterns to highlight operational aspects as well as typical parasitic artefacts. Combining a high-precision alignment table with separate housings for the neutron guides on kinematic mounts, the change-over between neutron guides with different focussing characteristics requires no readjustments of the experimental set-up. Exploiting substantial gain factors, we demonstrate the performance of this versatile neutron scattering module in a study of the effects of uniaxial stress on the domain populations in the transverse spin density wave phase of single crystal Cr.

Adams, T; Chacon, A; Wagner, J N; Rahn, M; Mhlbauer, S; Georgii, R; Pfleiderer, C; Bni, P

2014-01-01T23:59:59.000Z

265

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

266

Direct Measurement of Neutron?Neutron Scattering  

Science Journals Connector (OSTI)

In order to resolve long?standing discrepancies in indirect measurements of the neutron?neutron scattering length ann and contribute to solving the problem of the charge symmetry of the nuclear force the collaboration DIANNA (Direct Investigation of ann Association) plans to measure the neutron?neutron scattering cross section ? nn . The key issue of our approach is the use of the through?channel in the Russia reactor YAGUAR with a peak neutron flux of 1018 /cm2/s. The proposed experimental setup is described. Results of calculations are presented to connect ? nn with the nn?collision detector count rate and the neutron flux density in the reactor channel. Measurements of the thermal neutron fields inside polyethylene converters show excellent prospects for the realization of the direct nn?experiment.

E. I. Sharapov; C. D. Bowman; B. E. Crawford; W. I. Furman; C. R. Howell; B. G. Levakov; V. I. Litvin; W. I. Lychagin; A. E. Lyzhin; E. P. Magda; G. E. Mitchell; G. V. Muzichka; G. V. Nekhaev; Yu. V. Safronov; V. N. Shvetsov; S. L. Stephenson; A. V. Strelkov; W. Tornow

2003-01-01T23:59:59.000Z

267

Neutron-Mirror-Neutron Oscillations in a Trap  

E-Print Network [OSTI]

We calculate the rate of neutron-mirror-neutron oscillations for ultracold neutrons trapped in a storage vessel. Recent experimental bounds on the oscillation time are discussed.

B. Kerbikov; O. Lychkovskiy

2008-04-03T23:59:59.000Z

268

Neutronmirror-neutron oscillations in a trap  

Science Journals Connector (OSTI)

We calculate the rate of neutronmirror-neutron oscillations for ultracold neutrons trapped in a storage vessel. Recent experimental bounds on the oscillation time are discussed.

B. Kerbikov and O. Lychkovskiy

2008-06-27T23:59:59.000Z

269

Manuel Lujan Jr. Neutron Scattering Center Los Alamos Neutron...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

2013 LANSCE School on Neutron Scattering Geosciences & Materials in Extreme Environments Manuel Lujan Jr. Neutron Scattering Center Los Alamos Neutron Science Center Los Alamos...

270

ASYMMETRY IN THE OUTBURST OF SN 1987A DETECTED USING LIGHT ECHO SPECTROSCOPY  

SciTech Connect (OSTI)

We report direct evidence for asymmetry in the early phases of SN 1987A via optical spectroscopy of five fields of its light echo system. The light echoes allow the first few hundred days of the explosion to be reobserved, with different position angles providing different viewing angles to the supernova. Light echo spectroscopy therefore allows a direct spectroscopic comparison of light originating from different regions of the photosphere during the early phases of SN 1987A. Gemini multi-object spectroscopy of the light echo fields shows fine structure in the H{alpha} line as a smooth function of position angle on the near-circular light echo rings. H{alpha} profiles originating from the northern hemisphere of SN 1987A show an excess in redshifted emission and a blue knee, while southern hemisphere profiles show an excess of blueshifted H{alpha} emission and a red knee. This fine structure is reminiscent of the 'Bochum event' originally observed for SN 1987A, but in an exaggerated form. Maximum deviation from symmetry in the H{alpha} line is observed at position angles 16 Degree-Sign and 186 Degree-Sign , consistent with the major axis of the expanding elongated ejecta. The asymmetry signature observed in the H{alpha} line smoothly diminishes as a function of viewing angle away from the poles of the elongated ejecta. We propose an asymmetric two-sided distribution of {sup 56}Ni most dominant in the southern far quadrant of SN 1987A as the most probable explanation of the observed light echo spectra. This is evidence that the asymmetry of high-velocity {sup 56}Ni in the first few hundred days after explosion is correlated to the geometry of the ejecta some 25 years later.

Sinnott, B.; Welch, D. L.; Sutherland, P. G. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada)] [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Rest, A. [Space Telescope Science Institute, Baltimore, MD 21218 (United States)] [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Bergmann, M.

2013-04-10T23:59:59.000Z

271

Rotational Corrections to Neutron-Star Radius Measurements from Thermal Spectra  

E-Print Network [OSTI]

We calculate the rotational broadening in the observed thermal spectra of neutron stars spinning at moderate rates in the Hartle-Thorne approximation. These calculations accurately account for the effects of the second-order Doppler boosts as well as for the oblate shapes and the quadrupole moments of the neutron stars. We find that fitting the spectra and inferring the bolometric fluxes under the assumption that a star is not rotating causes an underestimate of the inferred fluxes and, thus, radii. The correction depends on the stellar spin, radius, and observer's inclination. For a 10 km neutron star spinning at 600 Hz, the rotational correction to the flux is ~1-4%, while for a 15 km neutron star with the same spin period, the correction ranges from 2% for pole-on sources to 12% for edge-on sources. We calculate the inclination-averaged corrections to inferred radii as a function of the neutron-star radius and mass and provide an empirical formula for the corrections. For realistic neutron star parameters (1.4 M$_\\odot$, 12 km, 600 Hz), the stellar radius is on the order of 4% larger than the radius inferred under the assumption that the star is not spinning.

Michi Baubock; Feryal Ozel; Dimitrios Psaltis; Sharon M. Morsink

2014-07-11T23:59:59.000Z

272

Driven dynamics and rotary echo of a qubit tunably coupled to a harmonic oscillator  

E-Print Network [OSTI]

We have investigated the driven dynamics of a superconducting flux qubit that is tunably coupled to a microwave resonator. We find that the qubit experiences an oscillating field mediated by off-resonant driving of the resonator, leading to strong modifications of the qubit Rabi frequency. This opens an additional noise channel, and we find that low-frequency noise in the coupling parameter causes a reduction of the coherence time during driven evolution. The noise can be mitigated with the rotary-echo pulse sequence, which, for driven systems, is analogous to the Hahn-echo sequence.

Gustavsson, Simon; Yan, Fei; Forn-Daz, Pol; Bolkhovsky, Vlad; Braje, Danielle; Fitch, George; Harrabi, Khalil; Lennon, Donna; Miloshi, Jovi; Murphy, Peter; Slattery, Rick; Spector, Steven; Turek, Ben; Weir, Terry; Welander, Paul B; Yoshihara, Fumiki; Cory, David G; Nakamura, Yasunobu; Orlando, Terry P; Oliver, William D

2012-01-01T23:59:59.000Z

273

Climatological study of radar echo pictures from Albrook Air Force Base, Panama  

E-Print Network [OSTI]

of the Gulf of San Miguel. The following are areas of minimum radar echo occur- rence over land: l. In the plains south of Aguadulce. 2. Along the northern slope of the mountain range north of Aguadulce. 3. Along the southeast coast. The wet season.... The following are areas of minimum radar echo occur- rance over' land: 1. In the plains south of Aguadulce. 2. Along the mountain ridge north of Aguadulce. 3. Along the north slope of the mountain north of the Gulf of San Miguel. 4. Along the coast south...

Bowen, Christopher

2012-06-07T23:59:59.000Z

274

Neutron crystallography aids drug design  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Neutron crystallography aids drug design Neutron crystallography aids drug design Researchers have used neutron crystallography for the first time to determine the structure of a...

275

Los Alamos Neutron Science Center  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

LINAC Outreach Affiliations Visiting LANSCE Facilities Isotope Production Facility Lujan Neutron Scattering Center MaRIE Proton Radiography Ultracold Neutrons Weapons Neutron...

276

Improvement of the polarized neutron interferometer setup demonstrating violation of a Bell-like inequality  

E-Print Network [OSTI]

For precise measurements with polarized neutrons high efficient spin-manipulation is required. We developed several neutron optical elements suitable for a new sophisticated setup, i.e., DC spin-turners and Larmor-accelerators which diminish thermal disturbances and depolarisation considerably. The gain in performance is exploited demonstrating violation of a Bell-like inequality for a spin-path entangled single-neutron state. The obtained value of S=2.365(13), which is much higher than previous measurements by neutron interferometry, is 28 $\\sigma$ above the limit of S=2 predicted by contextual hidden variable theories. The new setup is more flexible referring to state preparation and analysis, therefore new, more precise measurements can be carried out.

Hermann Geppert; Tobias Denkmayr; Stephan Sponar; Hartmut Lemmel; Yuji Hasegawa

2014-04-14T23:59:59.000Z

277

Conformational Switching between Protein Substates Studied with 2D IR Vibrational Echo Spectroscopy and Molecular Dynamics Simulations  

E-Print Network [OSTI]

Conformational Switching between Protein Substates Studied with 2D IR Vibrational Echo Spectroscopy. Three conformational substates have been identified for the carbonmonoxy form of myoglobin (Mb vibrational echo chemical exchange experiments are used to observed switching between two of these substates

Fayer, Michael D.

278

Nuclear Magnetic Resonance and Nuclear-Spin Dynamics in InP  

Science Journals Connector (OSTI)

Pulsed- and steady-state nuclear-magnetic-resonance measurements are reported for P31 in InP. Measurements on "solid echoes" permit identification of various contributions to the second moment of the resonance. The dominant P31-In115,113 contribution is found to be about a factor of 2 smaller than expected from dipole-dipole interactions alone. A proposed explanation is based on interference between pseudodipolar and dipolar interactions of similar magnitude but opposite sign. The time evolution of the P31 magnetization along the effective field in the rotating frame indicates the presence of a significant cross-relaxation effect involving the resonant spin-Zeeman reservoir and the nonresonant spin-spin reservoir.

M. Engelsberg and R. E. Norberg

1972-05-01T23:59:59.000Z

279

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 collimnated 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. The computer solves the following equation in the analysis: ##EQU1## where: N(x).DELTA.x=the number of neutron interactions measured between a position x and x+.DELTA.x, A.sub.i (E.sub.i).DELTA.E.sub.i =the number of incident neutrons with energy between E.sub.i and E.sub.i +.DELTA.E.sub.i, and C=C(E.sub.i)=N .sigma.(E.sub.i) where N=the number density of absorbing atoms in the position sensitive counter means and .sigma. (E.sub.i)=the average cross section of the absorbing interaction between E.sub.i and E.sub.i +.DELTA.E.sub.i.

Manglos, Stephen H. (East Syracuse, NY)

1989-06-06T23:59:59.000Z

280

Neutron Generator as a Neutron Source for BNCT  

Science Journals Connector (OSTI)

A neutron generator was investigated for a neutron source for BNCT. Neutron generators have some obvious advantages over nuclear reactors for this purpose. The neutron source is the reaction D(d,n)3He. Moderation...

Gad Shani; Lev Tsvang; Semion Rozin; Michael Quastel

1996-01-01T23:59:59.000Z

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

Fermi Liquid Instabilities in the Spin Channel  

SciTech Connect (OSTI)

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

282

SPIN DENSITY OF THE CANTED MOMENT IN 03B1-Fe2O3 (1) By S. J. PICKART,  

E-Print Network [OSTI]

avec des neutrons polarisés. On trouve que cette densité diffère de celle de l'ion Fe3+. Abstract. 2014 neutrons and found to differ from that of the Fe3+ ion. LE JOURNAL DE PHYSIQUE TOME 25, MAI 1964, as established by the original neutron diffraction measurements [3], consists of the Fe3 ~ spins in each (111

Boyer, Edmond

283

Neutron producing target for accelerator based neutron source for  

E-Print Network [OSTI]

247 Neutron producing target for accelerator based neutron source for NCT V. Belov1 , S. Fadeev1, Russia Summary Neutron producing targets for novel accelerator based neutron source [1, 2] are presented Neutron producing target is one of the main elements of proposed accelerator based facility for neutron

Taskaev, Sergey Yur'evich

284

Extended CO emission in the field of the light echo of V838 Mon  

E-Print Network [OSTI]

V838 Mon erupted at the beginning of 2002 becoming an extremely luminous star with L=10^6 L_sun. The outburst was followed by the spectacular light echo that revealed that the star is immersed in a diffuse and dusty medium, plausibly interstellar in nature. Low angular resolution observations in the lowest CO rotational transitions revealed a molecular emission from the direction of V838 Mon. The origin of this CO emission has not been established. In this paper we investigate the idea that the molecular emission originates in the material responsible for the optical light echo. We report on observations of 13 positions within the light echo in the two lowest rotational transitions of CO using the IRAM 30 m telescope. Emission in CO J=1-0 and J=2-1 was detected in three positions. In three other positions only weak J=1-0 lines were found. We conclude that the molecular emission from the direction of V838 Mon is extended and has a complex distribution. We identify the emission as arising from diffuse interstellar clouds and suggest that the CO-bearing gas and the echoing dust are collocated in the same interstellar cloud.

T. Kami?ski

2008-01-10T23:59:59.000Z

285

INVERTED ECHO SOUNDER DEVELOPMENT G. F. Chaplin and D. Randolph Watts  

E-Print Network [OSTI]

INVERTED ECHO SOUNDER DEVELOPMENT G. F. Chaplin and D. Randolph Watts Graduate School thermocline. Watts (1975), in discussing IES data from MODE I, showed that changes in dynamic height can evolving since its initial development. The first multi- instrument deployment was in MODE I (Watts

Rhode Island, University of

286

Myoglobin-CO Conformational Substate Dynamics: 2D Vibrational Echoes and MD Simulations  

E-Print Network [OSTI]

Myoglobin-CO Conformational Substate Dynamics: 2D Vibrational Echoes and MD Simulations Kusai A over a range of temperatures. The A1 and A3 conformational substates of MbCO are found to have assignments for the MbCO conformational substates. INTRODUCTION Protein dynamics have been the focus of both

Fayer, Michael D.

287

Myoglobin-CO Substate Structures and Dynamics: Multidimensional Vibrational Echoes and Molecular Dynamics  

E-Print Network [OSTI]

Myoglobin-CO Substate Structures and Dynamics: Multidimensional Vibrational Echoes and Molecular) having its imidazole nitrogen protonated (N -H). The two conformational substate structures B and R observed in the MD simulations are assigned to the spectroscopic A1 and A3 conformational substates of Mb

Fayer, Michael D.

288

Hydrogen bond breaking probed with multidimensional stimulated vibrational echo correlation spectroscopy  

E-Print Network [OSTI]

Hydrogen bond breaking probed with multidimensional stimulated vibrational echo correlation September 2003 Hydrogen bond population dynamics are extricated with exceptional detail using ultrafast ( 50 of methanol­OD oligomers in CCl4 . Hydrogen bond breaking makes it possible to acquire data for times much

Fayer, Michael D.

289

Water dynamics: dependence on local structure probed with vibrational echo correlation spectroscopy  

E-Print Network [OSTI]

Water dynamics: dependence on local structure probed with vibrational echo correlation spectroscopy­D stretching band of HOD in H2O and molecular dynamics simulations are employed to investigate water dynamics. The wavelength dependence of the measured dynamics demonstrates that different hydrogen bonded water species

Fayer, Michael D.

290

Three-Pulse Photon Echo of Finite Numbers of Molecules: Single-Molecule Traces  

E-Print Network [OSTI]

Three-Pulse Photon Echo of Finite Numbers of Molecules: Single- Molecule Traces Hui Dong and Graham, 6227]. To avoid this drawback of ensemble measurements and evaluate single-molecule behavior, a quantum the fluctuations inherent to single molecules. The current method takes advantage of the coherent state

Fleming, Graham R.

291

Neutron Scattering on Frustrated Magnets  

Science Journals Connector (OSTI)

Frustration denotes the inability of a system to satisfy all pairwise interactions and enables a large variety of fascinating ground states that depend on the very details of the interactions involved. The focus will be on neutron scattering studies of spinel compounds AB 2 X 4 . It is well known that the B?site ions form a pyrochlore lattice with inherent strong geometric frustration (GF). Among these compounds heavy fermion?like behaviour of LiV 2 O 4 and new kinds of magneto?elastic coupling phenomena in chromate spinels will be considered. Recently also the A?site spinels has been shown to be subject to strong frustration effects not only for the spin sector but also for the orbital and structural degrees of freedom. Corresponding ordering phenomena in MAl 2 O 4 ( M ?=? Mn Fe Co ) will be discussed.

A. Krimmel; V. Tsurkan; A. Loidl; H. Mutka; M. M. Koza

2008-01-01T23:59:59.000Z

292

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

293

Nuclear Spin Filter  

Science Journals Connector (OSTI)

A "spin filter" for selecting metastable hydrogen, deuterium, or tritium atoms with a given nuclear spin magnetic quantum number (mI) has been built and tested. With the device installed in the Los Alamos "Lamb-shift" polarized-ion source, we have obtained a deuterium negative-ion beam with ? 55% spin-state purity for mI=1,0,or-1. An improved magnetic field homogeneity in the apparatus is expected to increase the purity to ? 75%.

Joseph L. McKibben; George P. Lawrence; Gerald G. Ohlsen

1968-05-20T23:59:59.000Z

294

Spin Sum Rules and Polarizabilities: Results from Jefferson Lab  

E-Print Network [OSTI]

The nucleon spin structure has been an active, exciting and intriguing subject of interest for the last three decades. Recent experimental data on nucleon spin structure at low to intermediate momentum transfers provide new information in the confinement regime and the transition region from the confinement regime to the asymptotic freedom regime. New insight is gained by exploring moments of spin structure functions and their corresponding sum rules (i.e. the generalized Gerasimov-Drell-Hearn, Burkhardt-Cottingham and Bjorken). The Burkhardt-Cottingham sum rule is verified to good accuracy. The spin structure moments data are compared with Chiral Perturbation Theory calculations at low momentum transfers. It is found that chiral perturbation calculations agree reasonably well with the first moment of the spin structure function $g_1$ at momentum transfer of 0.05 to 0.1 GeV$^2$ but fail to reproduce the neutron data in the case of the generalized polarizability $\\delta_{LT}$ (the $\\delta_{LT}$ puzzle). New data have been taken on the neutron ($^3$He), the proton and the deuteron at very low $Q^2$ down to 0.02 GeV$^2$. They will provide benchmark tests of Chiral dynamics in the kinematic region where the Chiral Perturbation theory is expected to work.

Jian-ping Chen

2006-11-13T23:59:59.000Z

295

Instruments | Neutron Science | ORNL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

296

Neutron dose equivalent meter  

DOE Patents [OSTI]

A neutron dose equivalent detector for measuring neutron dose capable of accurately responding to neutron energies according to published fluence to dose curves. The neutron dose equivalent meter has an inner sphere of polyethylene, with a middle shell overlying the inner sphere, the middle shell comprising RTV.RTM. silicone (organosiloxane) loaded with boron. An outer shell overlies the middle shell and comprises polyethylene loaded with tungsten. The neutron dose equivalent meter defines a channel through the outer shell, the middle shell, and the inner sphere for accepting a neutron counter tube. The outer shell is loaded with tungsten to provide neutron generation, increasing the neutron dose equivalent meter's response sensitivity above 8 MeV.

Olsher, Richard H. (Los Alamos, NM); Hsu, Hsiao-Hua (Los Alamos, NM); Casson, William H. (Los Alamos, NM); Vasilik, Dennis G. (Los Alamos, NM); Kleck, Jeffrey H. (Menlo Park, CA); Beverding, Anthony (Foster City, CA)

1996-01-01T23:59:59.000Z

297

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

298

The Harwell Neutron Project  

Science Journals Connector (OSTI)

... 2 cm. thick, placed on three sides of the neutron booster. A layer of boron-10 metal placed between these tanks and the uranium-235 core prevents return of slow neutrons ...

M. J. POOLE; E. R. RAE

1960-01-30T23:59:59.000Z

299

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 wave 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, Jr., Herbert A. (Oak Ridge, TN)

1985-01-01T23:59:59.000Z

300

Neutrons - 88-Inch Cyclotron  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Neutrons Neutron beams are available at the 88-Inch Cyclotron. Available energies range of from 8 to 30 MeV, with fluxes of up to 1E8 neutronscm2sec. For more information,...

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

Thermal Neutron Scattering  

Science Journals Connector (OSTI)

... of its title. It is not for the nuclear physicist, nor even for the neutron physicist, but for the student of solids and liquids. "Thermal ... physicist, but for the student of solids and liquids. "Thermal neutron ...

G. E. BACON

1968-11-09T23:59:59.000Z

302

Neutron activation analysis  

Science Journals Connector (OSTI)

Neutron activation analysis (NAA) is an that relies on the measurement of ?-rays emitted from a sample that was irradiated by neutrons. The rate at which ?-rays are emitted from an element in a sample is dir...

James R. Budahn

1998-01-01T23:59:59.000Z

303

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

304

An effectual template bank for the detection of gravitational waves from inspiralling compact binaries with generic spins  

E-Print Network [OSTI]

We report the construction of a three-dimensional template bank for the search for gravitational waves from inspiralling binaries consisting of spinning compact objects. The parameter space consists of two dimensions describing the mass parameters and one "reduced-spin" parameter, which describes the secular (non-precessing) spin effects in the waveform. The template placement is based on an efficient stochastic algorithm and makes use of the semi-analytical computation of a metric in the parameter space. We demonstrate that for "low-mass" ($m_1 + m_2 \\lesssim 12\\,M_\\odot$) binaries, this template bank achieves effective fitting factors $\\sim0.92$--$0.99$ towards signals from generic spinning binaries in the advanced detector era over the entire parameter space of interest (including binary neutron stars, binary black holes, and black hole-neutron star binaries). This provides a powerful and viable method for searching for gravitational waves from generic spinning low-mass compact binaries. Under the assumption that spin magnitudes of black-holes [neutron-stars] are uniformly distributed between 0--0.98 [0 -- 0.4] and spin angles are isotropically distributed, the expected improvement in the average detection volume (at a fixed signal-to-noise-ratio threshold) of a search using this reduced-spin bank is $\\sim20-52\\%$, as compared to a search using a non-spinning bank.

P. Ajith; N. Fotopoulos; S. Privitera; A. Neunzert; N. Mazumder; A. J. Weinstein

2014-05-21T23:59:59.000Z

305

EUV/soft x-ray spectra for low B neutron stars  

SciTech Connect (OSTI)

Recent ROSAT and EUVE detections of spin-powered neutron stars suggest that many emit ``thermal`` radiation, peaking in the EUV/soft X-ray band. These data constrain the neutron stars` thermal history, but interpretation requires comparison with model atmosphere computations, since emergent spectra depend strongly on the surface composition and magnetic field. As recent opacity computations show substantial change to absorption cross sections at neutron star photospheric conditions, we report here on new model atmosphere computations employing such data. The results are compared with magnetic atmosphere models and applied to PSR J0437-4715, a low field neutron star.

Romani, R.W.; Rajagopal, M. [Stanford Univ., CA (United States). Dept. of Physics; Rogers, F.J.; Iglesias, C.A. [Lawrence Livermore National Lab., CA (United States)

1995-05-23T23:59:59.000Z

306

Analyzing the Effects of Neutron Polarizabilities in Elastic Compton Scattering off ${}^3He$  

E-Print Network [OSTI]

Motivated by the fact that a polarized ${}^3He$ nucleus behaves as an `effective' neutron target, we examine manifestations of neutron electromagnetic polarizabilities in elastic Compton scattering from the Helium-3 nucleus. We calculate both unpolarized and double-polarization observables using chiral perturbation theory to next-to-leading order (${\\mathcal O}(e^2 Q)$) at energies, $\\omega \\lsim m_{\\pi}$, where $m_{\\pi}$ is the pion mass. Our results show that the unpolarized differential cross section can be used to measure neutron electric and magnetic polarizabilities, while two double-polarization observables are sensitive to different linear combinations of the four neutron spin polarizabilities.

Deepshikha Shukla; Andreas Nogga; Daniel R. Phillips

2008-12-01T23:59:59.000Z

307

Neutron computed tomography  

E-Print Network [OSTI]

to make the Donner Algorithms run. TABLE OF CONTEliiTS CHAPTF. . R I NEI. TRON RADIOGRAPHY . I. 1 Background . I. 2 Theory . l. 3 Neutron Beam Characterization I. 4 Image Detectors . COMPI'TED TOMOGRAPHY . Il I Background . II. 2 Notation II. 3... data which is generated by rays traveling (and being attenuated) in straight lines. However in neutron radiography, what is measured is, to most extents, the levels of neutrons which are not attenuated. Neutrons are particles. They scatter...

Russell, Clifford Marlow

2012-06-07T23:59:59.000Z

308

Neutron scattering and ribosomes  

Science Journals Connector (OSTI)

... the complexity of intra-ribosomal interactions. This is however by no means the case with neutron ...neutronscattering ...

Richard Brimacombe

1977-06-23T23:59:59.000Z

309

Results from the spin programme at COSY-ANKE  

E-Print Network [OSTI]

Some of the important results from the COSY-Juelich spin programme are summarised. These include the measurement of the deuteron beam momentum through the excitation of a depolarising resonance, which allowed the mass of the eta-meson to be determined to high precision. The charge exchange of polarised deuterons on hydrogen gave rise to a detailed study of the spin dependence of large angle neutron-proton elastic scattering amplitudes. The measurements of the cross section and analysing powers for pion production in both pp and pn collisions at 353 MeV could be described very successfully in terms of a partial wave decomposition.

A. Kacharava; C. Wilkin

2012-12-12T23:59:59.000Z

310

Resonant Spin Excitation in an Overdoped High Temperature Superconductor  

Science Journals Connector (OSTI)

An inelastic neutron scattering study of overdoped Bi2Sr2CaCu2O8+? ( Tc=83K) has revealed a resonant spin excitation in the superconducting state. The mode energy is Eres=38.0meV, significantly lower than in optimally doped Bi2Sr2CaCu2O8+? ( Tc=91K, Eres=42.4meV). This observation, which indicates a constant ratio Eres/kBTc?5.4, helps resolve a long-standing controversy about the origin of the resonant spin excitation in high temperature superconductors.

H. He; Y. Sidis; P. Bourges; G. D. Gu; A. Ivanov; N. Koshizuka; B. Liang; C. T. Lin; L. P. Regnault; E. Schoenherr; B. Keimer

2001-02-19T23:59:59.000Z

311

Neutron removal cross section as a measure of neutron skin  

Science Journals Connector (OSTI)

We study the relation between neutron removal cross section (?-N) and neutron skin thickness for finite neutron-rich nuclei using the statistical abrasion ablation model. Different sizes of neutron skin are obtained by adjusting the diffuseness parameter of neutrons in the Fermi distribution. It is demonstrated that there is a good linear correlation between ?-N and the neutron skin thickness for neutron-rich nuclei. Further analysis suggests that the relative increase of neutron removal cross section could be used as a quantitative measure for neutron skin thickness in neutron-rich nuclei.

D. Q. Fang (???); Y. G. Ma (???); X. Z. Cai (???); W. D. Tian (???); H. W. Wang (???)

2010-04-07T23:59:59.000Z

312

The neutron warhead decision  

Science Journals Connector (OSTI)

The neutron warhead decision ... Nuclear war moved a step closer last week with the U.S.'s decision to move ahead with production of so-called neutron warheads for use on short-range missiles and in artillery shells. ... And neutron weapons would be almost as effective on ... ...

MICHAEL HEYLIN

1981-08-17T23:59:59.000Z

313

Ultrafast nuclear spin polarization for isotopes with large nuclear spin  

Science Journals Connector (OSTI)

We theoretically investigate the temporal dynamics of nuclear spin induced by short laser pulses. To realize ultrafast nuclear spin polarization, we coherently excite the hyperfine...

Nakajima, Takashi

2009-01-01T23:59:59.000Z

314

Constraining interactions mediated by axion-like particles with ultracold neutrons  

E-Print Network [OSTI]

We report a new limit on a possible short range spin-dependent interaction from the precise measurement of the ratio of Larmor precession frequencies of stored ultracold neutrons and $^{199}$Hg atoms confined in the same volume. The measurement was performed in a $\\sim$1$\\mu$ T vertical magnetic holding field with the apparatus searching for a permanent electric dipole moment of the neutron at the Paul Scherrer Institute. A possible coupling between freely precessing polarized neutron spins and unpolarized nucleons of the wall material can be investigated by searching for a tiny change of the precession frequencies of neutron and mercury spins. Such a frequency change can be interpreted as a consequence of a short range spin-dependent interaction that could possibly be mediated by axions or axion-like particles. The interaction strength is proportional to the CP violating product of scalar and pseudoscalar coupling constants $g_Sg_P$. Our result confirms limits from complementary experiments with spin-polarized nuclei in a model-independent way. Limits from other neutron experiments are improved by up to two orders of magnitude in the interaction range of $10^{-6}<\\lambda<10^{-4}$ m.

S. Afach; G. Ban; G. Bison; K. Bodek; M. Burghoff; M. Daum; M. Fertl; B. Franke; Z. D. Gruji?; V. Hlaine; M. Kasprzak; Y. Kermadic; K. Kirch; P. Knowles; H. -C. Koch; S. Komposch; A. Kozela; J. Krempel; B. Lauss; T. Lefort; Y. Lemire; A. Mtchedlishvili; O. Naviliat-Cuncic; F. M. Piegsa; G. Pignol; P. N. Prashanth; G. Qumner; D. Rebreyend; D. Ries; S. Roccia; P. Schmidt-Wellenburg; A. Schnabel; N. Severijns; J. Voigt; A. Weis; G. Wyszynski J. Zejma; J. Zenner; G. Zsigmond

2014-12-11T23:59:59.000Z

315

Rotational Corrections to Neutron-Star Radius Measurements from Thermal Spectra  

E-Print Network [OSTI]

We calculate the rotational broadening in the observed thermal spectra of neutron stars spinning at moderate rates in the Hartle-Thorne approximation. These calculations accurately account for the effects of the second-order Doppler boosts as well as for the oblate shapes and the quadrupole moments of the neutron stars. We find that fitting the spectra and inferring the bolometric fluxes under the assumption that a star is not rotating causes an underestimate of the inferred fluxes and, thus, radii. The correction depends on the stellar spin, radius, and observer's inclination. For a 10 km neutron star spinning at 600 Hz, the rotational correction to the flux is ~1-4%, while for a 15 km neutron star with the same spin period, the correction ranges from 2% for pole-on sources to 12% for edge-on sources. We calculate the inclination-averaged corrections to inferred radii as a function of the neutron-star radius and mass and provide an empirical formula for the corrections. For realistic neutron star parameters ...

Baubock, Michi; Psaltis, Dimitrios; Morsink, Sharon M

2014-01-01T23:59:59.000Z

316

Status of Spin Physics  

E-Print Network [OSTI]

Fundamental spin physics has made striking progresses in the last years; new ideas, experiments and data interpretations have been proposed and keep emerging. A review of some of the most important issues in the spin structure of nucleons is made and prospects for the future are discussed.

Mauro Anselmino

2001-07-09T23:59:59.000Z

317

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

318

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

319

Principles of neutron reflection  

SciTech Connect (OSTI)

Neutron reflection is perhaps the most developed branch of slow neutrons optics, which in itself is a direct consequence of the undulatory nature of the neutron. After reviewing the basic types of interactions (nuclear and magnetic) between neutrons and matter, the formalism is introduced to calculate the reflectivity from a sample composed of stacked flat layers and, inversely, to calculate the stacking from reflectivity measurements. Finally, a brief survey of the applications of neutron reflection is given, both in technology and in fundamental research. 32 refs., 6 figs.

Felcher, G.P.

1988-08-01T23:59:59.000Z

320

Spin superconductor in ferromagnetic graphene  

Science Journals Connector (OSTI)

We show a spin superconductor in ferromagnetic graphene as the counterpart to the charge superconductor in which a spin-polarized electron-hole pair plays the role of the spin 2(?/2) Cooper pair with a neutral charge. We present a BCS-type theory for the spin superconductor. With the London-type equations of the super-spin-current density, we show the existence of an electric Meissner effect against a spatial varying electric field. We further study a spin superconductor/normal conductor/spin superconductor junction and predict a spin-current Josephson effect.

Qing-feng Sun; Zhao-tan Jiang; Yue Yu; X. C. Xie

2011-12-02T23:59:59.000Z

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.


321

On neutron numbers and atomic masses  

Science Journals Connector (OSTI)

On neutron numbers and atomic masses ... Assigning neutron numbers, correct neutron numbers, and atomic masses and nucleon numbers. ...

R. Heyrovsk

1992-01-01T23:59:59.000Z

322

Spallation Neutron Source, SNS  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

323

The Neutron Lifetime  

E-Print Network [OSTI]

The decay of the free neutron into a proton, electron, and antineutrino is the prototype semileptonic weak decay and the simplest example of nuclear beta decay. The nucleon vector and axial vector weak coupling constants G_V and G_A determine the neutron lifetime as well as the strengths of weak interaction processes involving free neutrons and protons that are important in astrophysics, cosmology, solar physics and neutrino detection. In combination with a neutron decay angular correlation measurement, the neutron lifetime can be used to determine the first element of the CKM matrix Vud. Unfortunately the two main experimental methods for measuring the neutron lifetime currently disagree by almost 4 sigma. I will present a brief review of the status of the neutron lifetime and prospects for the future.

Wietfeldt, F E

2014-01-01T23:59:59.000Z

324

The Neutron Lifetime  

E-Print Network [OSTI]

The decay of the free neutron into a proton, electron, and antineutrino is the prototype semileptonic weak decay and the simplest example of nuclear beta decay. The nucleon vector and axial vector weak coupling constants G_V and G_A determine the neutron lifetime as well as the strengths of weak interaction processes involving free neutrons and protons that are important in astrophysics, cosmology, solar physics and neutrino detection. In combination with a neutron decay angular correlation measurement, the neutron lifetime can be used to determine the first element of the CKM matrix Vud. Unfortunately the two main experimental methods for measuring the neutron lifetime currently disagree by almost 4 sigma. I will present a brief review of the status of the neutron lifetime and prospects for the future.

F. E. Wietfeldt

2014-11-13T23:59:59.000Z

325

Supergiant Pulses from Extragalactic Neutron Stars  

E-Print Network [OSTI]

We evaluate the hypothesis that extragalactic radio bursts originate from neutron stars. These could be active pulsars or dormant, slowly spinning objects, but the different population distances for these two classes require correspondingly different contributions to burst dispersion measures from any host or intervening galaxies combined with the intergalactic medium. The large, apparent burst rate $\\sim 10^4~$ sky$^{-1}~$ day$^{-1}$ is comparable to the core-collapse supernova rate in a Hubble volume and can be accommodated by a single burst per object in the resulting large reservoir of $\\sim 10^{17}~$ neutron stars. A smaller population distance requires more bursts per object but the likelihood of seeing repeated bursts from any single object is extremely low on human timescales. Gravitational microlensing could play a role for high redshift sources. Extrapolation of the Crab pulsar's giant pulses --- exemplars of coherent, high brightness temperature radiation --- to a rate of one per $10^3~$yr yields a...

Cordes, J M

2015-01-01T23:59:59.000Z

326

Periodic magnetic field as a polarized and focusing thermal neutron spectrometer and monochromator  

SciTech Connect (OSTI)

A novel periodic magnetic field (PMF) optic is shown to act as a prism, lens, and polarizer for neutrons and particles with a magnetic dipole moment. The PMF has a two-dimensional field in the axial direction of neutron propagation. The PMF alternating magnetic field polarity provides strong gradients that cause separation of neutrons by wavelength axially and by spin state transversely. The spin-up neutrons exit the PMF with their magnetic spins aligned parallel to the PMF magnetic field, and are deflected upward and line focus at a fixed vertical height, proportional to the PMF period, at a downstream focal distance that increases with neutron energy. The PMF has no attenuation by absorption or scatter, as with material prisms or crystal monochromators. Embodiments of the PMF include neutron spectrometer or monochromator, and applications include neutron small angle scattering, crystallography, residual stress analysis, cross section measurements, and reflectometry. Presented are theory, experimental results, computer simulation, applications of the PMF, and comparison of its performance to Stern-Gerlach gradient devices and compound material and magnetic refractive prisms.

Cremer, J. T.; Williams, D. L.; Fuller, M. J.; Gary, C. K.; Piestrup, M. A. [Adelphi Technology, Inc., 2003 East Bayshore Rd., Redwood City, California 94063 (United States); Pantell, R. H.; Feinstein, J. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Flocchini, R. G.; Boussoufi, M.; Egbert, H. P.; Kloh, M. D.; Walker, R. B. [Davis McClellan Nuclear Radiation Center, University of California, McClellan, California 95652 (United States)

2010-01-15T23:59:59.000Z

327

Microscopic approach to the U(6/44)?SpinBFF(6) Hamiltonian of the interacting boson-fermion-fermion model  

Science Journals Connector (OSTI)

Relations between the SpinBFF(6) symmetry Hamiltonian for odd-odd systems and the interacting boson-fermion-fermion model (IBFFM) Hamiltonian are investigated. An exact equivalence is established by slightly revising the exchange term of the IBFFM Hamiltonian. The SpinBFF(6) symmetry is realized approximately in IBFFM by extending the quasiparticle configuration space for odd fermions. The proton-neutron residual interaction associated with the appearance of dynamical symmetry is compared to effective proton-neutron forces.

V. Paar; D. Vretenar; C. De Coster; K. Heyde; O. Scholten

1992-01-01T23:59:59.000Z

328

Anisotropic Spin Relaxation in Graphene  

Science Journals Connector (OSTI)

Spin relaxation in graphene is investigated in electrical graphene spin valve devices in the nonlocal geometry. Ferromagnetic electrodes with in-plane magnetizations inject spins parallel to the graphene layer. They are subject to Hanle spin precession under a magnetic field B applied perpendicular to the graphene layer. Fields above 1.5T force the magnetization direction of the ferromagnetic contacts to align to the field, allowing injection of spins perpendicular to the graphene plane. A comparison of the spin signals at B=0 and B=2??T shows a 20% decrease in spin relaxation time for spins perpendicular to the graphene layer compared to spins parallel to the layer. We analyze the results in terms of the different strengths of the spin-orbit effective fields in the in-plane and out-of-plane directions and discuss the role of the Elliott-Yafet and Dyakonov-Perel mechanisms for spin relaxation.

N. Tombros; S. Tanabe; A. Veligura; C. Jozsa; M. Popinciuc; H. T. Jonkman; B. J. van Wees

2008-07-25T23:59:59.000Z

329

Imaging and Neutrons - IAN 2006 - Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

330

Nuclear Spins of Silver-104 and Silver-106  

Science Journals Connector (OSTI)

The nuclear spins of four neutron-deficient isotopes of silver have been measured by atomic-beam methods. The results are: for 27-min Ag104, I=2; for 1.2-hr Ag104, I=5; for 24-min Ag106, I=1; and for 8.3-day Ag106, I=6. Of these, the result for 1.2-hr Ag104 has not been reported previously.

W. B. Ewbank; L. L. Marino; W. A. Nierenberg; H. A. Shugart; H. B. Silsbee

1959-08-01T23:59:59.000Z

331

Dynamics of Composite Haldane Spin Chains in IPA-CuCl3  

SciTech Connect (OSTI)

Magnetic excitations in the quasi-one-dimensional antiferromagnet IPA-CuCl{sub 3} are studied by cold neutron inelastic scattering. Strongly dispersive gap excitations are observed. Contrary to previously proposed models, the system is best described as an asymmetric quantum spin ladder. The observed spectrum is interpreted in terms of composite Haldane spin chains. The key difference from actual S = 1 chains is a sharp cutoff of the single-magnon spectrum at a certain critical wave vector.

Masuda, Takatsugu [ORNL; Zheludev, Andrey I [ORNL; Manaka, H. [Kagoshima University, Kagoshima JAPAN; Regnault, L.-P. [CEA, Grenoble, France; Chung, J.-H. [National Institute of Standards and Technology (NIST); Qiu, Y. [National Institute of Standards and Technology (NIST)

2006-01-01T23:59:59.000Z

332

Appendix - Neutron Scattering Lengths and Cross Sections  

Science Journals Connector (OSTI)

Abstract In this appendix, we present an updated table of neutron scattering lengths and cross sections for most of the known nuclides, based on preexisting works. We include the coherent and incoherent scattering lengths, as well as the spin-dependent scattering lengths b+ and b?, in cases where this information is available. Also presented are the scattering coherent, incoherent, total, and absorption cross sections. We present an overview of the fundamental theory of the magnitudes to which the table is referred, and also a summary of the main experimental techniques used in determining these magnitudes.

Javier Dawidowski; Jos Rolando Granada; Javier Roberto Santisteban; Florencia Cantargi; Luis Alberto Rodrguez Palomino

2013-01-01T23:59:59.000Z

333

Deeply Virtual Compton Scattering off the neutron  

E-Print Network [OSTI]

The present experiment exploits the interference between the Deeply Virtual Compton Scattering (DVCS) and the Bethe-Heitler processes to extract the imaginary part of DVCS amplitudes on the neutron and on the deuteron from the helicity-dependent D$({\\vec e},e'\\gamma)X$ cross section measured at $Q^2$=1.9 GeV$^2$ and $x_B$=0.36. We extract a linear combination of generalized parton distributions (GPDs) particularly sensitive to $E_q$, the least constrained GPD. A model dependent constraint on the contribution of the up and down quarks to the nucleon spin is deduced.

M. Mazouz; A. Camsonne; C. Muoz Camacho; for the Jefferson Lab Hall A collaboration

2007-09-04T23:59:59.000Z

334

The Scattering of Slow Neutrons by Ortho- and Paradeuterium  

Science Journals Connector (OSTI)

Information relating to the spin dependence of the neutron-deuteron interaction can be obtained from slow neutron scattering experiments in ortho- and paradeuterium. Theoretical formulae have been derived for the cross sections of the various transitions among the molecular rotational levels, which involve the scattering amplitudes a32 and a12 for the two spin states of the neutron-deuteron system. In particular, numerical results are given for the first few transitions originating from the ground levels of the ortho- and para-systems with neutron energies not exceeding 0.05 ev. The influence of the thermal motion of the molecule is described, and explicit formulae are given for the important transitions occurring at small neutron energies, on the assumption that the D2 is in gaseous form at low temperature. The ratio of the ortho- and para-cross sections, under these conditions, is examined in its dependence upon the ratio of the scattering amplitudes. If the scattering amplitudes are of the same sign, the cross-section ratio is never greater than 1.31 and attains this magnitude only for small values of a32 relative to a12. If, however, the amplitudes are of opposite sign, this ratio can be as large as 1.75 and always exceeds 1.11. This experiment measures only the magnitudes of the amplitude combinations (2a32+a12) and (a32-a12), but not their signs, and thus leaves a fourfold ambiguity in interpretation. The possibility is discussed of determining the sign of (2a32+a12) by scattering experiments in HD. It is pointed out that the sign of (a32-a12) cannot be fixed by any experiment in which the deuteron spin is unoriented in space. An alternative experimental method, involving the depolarization of neutrons, is mentioned.

M. Hamermesh and Julian Schwinger

1946-03-01T23:59:59.000Z

335

Microsoft Word - TR_SiteEcho_Final_R1-V2.doc  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

336

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

Broader source: Energy.gov (indexed) [DOE]

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

337

Echo?Ranging Device Used to Measure the Size of a Well at Camp Century  

Science Journals Connector (OSTI)

The echo?ranging device used to determine the size of a heat?sink well at Camp Century Greenland is briefly described. A rotating bariumtitanate narrow?beam transducer served as both transmitter and receiver. Short 500?kc/sec acoustic pulses were generated at the transducer by shock excitation. The device was designed to operate to a maximum range of 500 ft when suspended from a 1200?ft cable. A graphic recorder presented the echo time as a horizontal cross section of the well. The configuration of the well was determined by repeating the horizontal scan at successive depths. Tests at Camp Century revealed that the well was approximately 200 ft in diam with a water depth of approximately 100 ft. Good repeatability and an accuracy of less than 6 in. was demonstrated. The volume of the well was determined to be approximately 2 million cu ft. [Work supported by the U. S. Army.

O. Charles Mullineaux

1964-01-01T23:59:59.000Z

338

Data analysis Pipeline for EChO end-to-end simulations  

E-Print Network [OSTI]

Atmospheric spectroscopy of extrasolar planets is an intricate business. Atmospheric signatures typically require a photometric precision of $1 \\times 10^{-4}$ in flux over several hours. Such precision demands high instrument stability as well as an understanding of stellar variability and an optimal data reduction and removal of systematic noise. In the context of the EChO mission concept, we here discuss the data reduction and analysis pipeline developed for the EChO end-to-end simulator EChOSim. We present and discuss the step by step procedures required in order to obtain the final exoplanetary spectrum from the EChOSim`raw data' using a simulated observation of the secondary eclipse of the hot-Neptune 55 Cnc e.

Waldmann, Ingo P

2014-01-01T23:59:59.000Z

339

Correlation Functions and Spin  

E-Print Network [OSTI]

The k-electron correlation function of a free chaotic electron beam is derived with the spin degree of freedom taken into account. It is shown that it can be expressed with the help of correlation functions for a polarized electron beam of all orders up to k and the degree of spin polarization. The form of the correlation function suggests that if the electron beam is not highly polarized, observing multi-particle correlations should be difficult. The result can be applied also to chaotic photon beams, the degree of spin polarization being replaced by the degree of polarization.

T. Tyc

2000-06-30T23:59:59.000Z

340

Nuclear-spin noise  

Science Journals Connector (OSTI)

The spectral density of the Nyquist noise current in a tuned circuit coupled to a sample of nuclear spins has been measured at He4 temperatures with a dc SQUID used as a rf amplifier. When the sample is in thermal equilibrium, a dip is observed in the spectral density at the Larmor frequency. For zero spin polarization, on the other hand, a bump in the spectral density is observed. This bump is due to temperature-independent fluctuations in the transverse component of magnetization, and represents spontaneous emission from the spins into the circuit.

Tycho Sleator; Erwin L. Hahn; Claude Hilbert; John Clarke

1985-10-21T23:59:59.000Z

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.


341

EIS-0317-S1: Kangley-Echo Lake Transmission Line Project Final Environmental Impact Statement  

Broader source: Energy.gov [DOE]

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.

342

On the potential of the EChO mission to characterise gas giant atmospheres  

E-Print Network [OSTI]

Space telescopes such as EChO (Exoplanet Characterisation Observatory) and JWST (James Webb Space Telescope) will be important for the future study of extrasolar planet atmospheres. Both of these missions are capable of performing high sensitivity spectroscopic measurements at moderate resolutions in the visible and infrared, which will allow the characterisation of atmospheric properties using primary and secondary transit spectroscopy. We use the NEMESIS radiative transfer and retrieval tool (Irwin et al. 2008, Lee et al. 2012) to explore the potential of the proposed EChO mission to solve the retrieval problem for a range of H2-He planets orbiting different stars. We find that EChO should be capable of retrieving temperature structure to ~200 K precision and detecting H2O, CO2 and CH4 from a single eclipse measurement for a hot Jupiter orbiting a Sun-like star and a hot Neptune orbiting an M star, also providing upper limits on CO and NH3. We provide a table of retrieval precisions for these quantities in ...

Barstow, Joanna K; Irwin, Patrick G J; Bowles, Neil; Fletcher, Leigh N; Lee, Jae-Min

2012-01-01T23:59:59.000Z

343

Kangley-Echo Lake Transmission Line Project Final Environmental Impact Statement  

SciTech Connect (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

344

Relativistic viscous hydrodynamics for heavy-ion collisions with ECHO-QGP  

E-Print Network [OSTI]

We present ECHO-QGP, a numerical code for $(3+1)$-dimensional relativistic viscous hydrodynamics designed for the modeling of the space-time evolution of the matter created in high energy nuclear collisions. The code has been built on top of the \\emph{Eulerian Conservative High-Order} astrophysical code for general relativistic magneto-hydrodynamics [\\emph{Del Zanna et al., Astron. Astrophys. 473, 11, 2007}] and here it has been upgraded to handle the physics of the Quark-Gluon Plasma. ECHO-QGP features second-order treatment of causal relativistic viscosity effects in both Minkowskian or Bjorken coordinates; partial or complete chemical equilibrium of hadronic species before kinetic freeze-out; initial conditions based on the optical Glauber model, including a Monte-Carlo routine for event-by-event fluctuating initial conditions; a freeze-out procedure based on the Cooper-Frye prescription. The code is extensively validated against several test problems and results always appear accurate, as guaranteed by the combination of the conservative (shock-capturing) approach and the high-order methods employed. ECHO-QGP can be extended to include evolution of the electromagnetic fields coupled to the plasma.

L. Del Zanna; V. Chandra; G. Inghirami; V. Rolando; A. Beraudo; A. De Pace; G. Pagliara; A. Drago; F. Becattini

2013-05-30T23:59:59.000Z

345

Spin waves in a persistent spin-current Fermi liquid  

Science Journals Connector (OSTI)

We report two theoretical results for transverse spin waves, which arise in a system with a persistent spin current. Using Fermi liquid theory, we introduce a spin current in the ground state of a polarized or unpolarized Fermi liquid, and we derive the resultant spin waves using the Landau kinetic equation. The resulting spin waves have a q1 and q1/2 dispersion to leading order for the polarized and unpolarized systems, respectively.

J. D. Feldmann and K. S. Bedell

2010-06-14T23:59:59.000Z

346

International Spin Physics 2014 Summary  

E-Print Network [OSTI]

The Stern-Gerlach experiment and the origin of electron spin are described in historical context. SPIN 2014 occurs on the fortieth anniversary of the first International High Energy Spin Physics Symposium at Argonne in 1974. A brief history of the international spin conference series is presented.

Milner, Richard G

2015-01-01T23:59:59.000Z

347

International Spin Physics 2014 Summary  

E-Print Network [OSTI]

The Stern-Gerlach experiment and the origin of electron spin are described in historical context. SPIN 2014 occurs on the fortieth anniversary of the first International High Energy Spin Physics Symposium at Argonne in 1974. A brief history of the international spin conference series is presented.

Richard G. Milner

2015-02-06T23:59:59.000Z

348

Searches for Exotic Interactions Using Neutron Spin Rotation  

E-Print Network [OSTI]

Various theories beyond the Standard Model predict new particles with masses in the sub-eV range with very weak couplings to ordinary matter. I present both measured and projected limits on the strengths of two possible interactions that could be mediated by these new particles, and how one may additionally use these results to search for in matter gravitational torsion.

Haddock, Chris

2014-01-01T23:59:59.000Z

349

Neutron Scattering Studies of spin excitations in hole-doped  

E-Print Network [OSTI]

-Rivera5,6 , J. W. Lynn5 , Tao Xiang2,7 , Jiangping Hu2,8 & Pengcheng Dai1,2,3 1 Department of Physics

Wang, Wei Hua

350

Localized Spins on Graphene  

Science Journals Connector (OSTI)

The problem of a magnetic impurity, atomic or molecular, absorbed on top of a carbon atom in otherwise clean graphene is studied using the numerical renormalization group. The spectral, thermodynamic, and scattering properties of the impurity are described in detail. In the presence of a small magnetic field, the low-energy electronic features of graphene make it possible to inject spin-polarized currents through the impurity using a scanning tunneling microscope. Furthermore, the impurity scattering becomes strongly spin dependent and for a finite impurity concentration it leads to spin-polarized bulk currents and a large magnetoresistance. In gated graphene the impurity spin is Kondo screened at low temperatures. However, at temperatures larger than the Kondo temperature, the anomalous magnetotransport properties are recovered.

P. S. Cornaglia; Gonzalo Usaj; C. A. Balseiro

2009-01-27T23:59:59.000Z

351

Cold neutron research facility at the Budapest Neutron Centre  

Science Journals Connector (OSTI)

The new cold neutron research facility has been routinely operated at the Budapest Neutron Centre (BNC) since February 2001. This ... of equipment consists of a liquid hydrogen cold neutron source, an optimised s...

L. Rosta

2002-12-01T23:59:59.000Z

352

Measurement of Thermal Neutron Flux in Photo-Neutron Source  

Science Journals Connector (OSTI)

The Photo-Neutron Source (PNS) project is a study ... design, simulation and construction an accelerator based neutron source for Boron Neutron Capture Therapy (BNCT). The system uses ... medical linear accelerat...

A. Taheri; A. Torkamani; A. Pazirandeh

2013-01-01T23:59:59.000Z

353

Neutron sources and applications  

SciTech Connect (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

354

Moments of the neutron $g_2$ structure function at intermediate $Q^2$  

E-Print Network [OSTI]

We present new experimental results of the $^3$He spin structure function $g_2$ in the resonance region at $Q^2$ values between 1.2 and 3.0 (GeV/c)$^2$. Spin dependent moments of the neutron were then extracted. Our main result, the resonance contribution to the neutron $d_2$ matrix element, was found to be small at $$=2.4 (GeV/c)$^2$ and in agreement with the Lattice QCD calculation. The Burkhardt-Cottingham sum rule for $^3$He and the neutron was tested with the measured data and using the Wandzura-Wilczek relation for the low $x$ unmeasured region. A small deviation was observed at $Q^2$ values between 0.5 and 1.2 (GeV/c)$^2$ for the neutron.

P. Solvignon; N. Liyanage; J. -P. Chen; Seonho Choi; K. Slifer; K. Aniol; T. Averett; W. Boeglin; A. Camsonne; G. D. Cates; C. C. Chang; E. Chudakov; B. Craver; F. Cusanno; A. Deur; D. Dutta; R. Ent; R. Feuerbach; S. Frullani; H. Gao; F. Garibaldi; R. Gilman; C. Glashausser; V. Gorbenko; O. Hansen; D. W. Higinbotham; H. Ibrahim; X. Jiang; M. Jones; A. Kelleher; J. Kelly; C. Keppel; W. Kim; W. Korsch; K. Kramer; G. Kumbartzki; J. J. LeRose; R. Lindgren; B. Ma; D. J. Margazioti; P. Markowitz; K. McCormick; Z. -E. Meziani; R. Michaels; B. Moffit; P. Monaghan; C. Munoz Camacho; K. Paschke; B. Reitz; A. Saha; R. Shneor; J. Singh; V. Sulkosky; A. Tobias; G. M. Urciuoli; K. Wang; K. Wijesooriya; B. Wojtsekhowski; S. Woo; J. -C. Yang; X. Zheng; L. Zhu

2014-03-14T23:59:59.000Z

355

Ultra-low-temperature neutron diffraction. Final report, July 1, 1983-June 30, 1985. Final report  

SciTech Connect (OSTI)

An ultra-low-temperature neutron diffraction facility has been constructed at Argonne National Laboratory. The initial and primary purpose of this facility is to study nuclear magnetic ordering phenomenon. Magnetic structure information is commonly recognized as being fundamental to the progress in theoretical and experimental efforts in the field of magnetism. We have initiated study of the nuclear spin in solid /sup 3/He and in metals. In /sup 3/He the nuclear spins order at 1.1 mK. Structure information for neutron diffraction would contribute significantly to this problem of nuclear magnetism. Despite substantial experimental difficulties, careful evaluation suggests that examination of the nuclear structure in this unique quantum crystal is indeed feasible by neutron diffraction. Substantial progress has been made in growing single crystals of /sup 3/He and establishing its temperature in the presence of a neutron flux. We have also initiated investigation of nuclear ordering in copper and PrCu/sub 6/.

Halperin, W.P.; Ketterson, J.B.

1985-07-01T23:59:59.000Z

356

Spallation Neutron Source  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

357

Spin-Diffusion Measurements in Hydrogen between 20 and 55K  

Science Journals Connector (OSTI)

The spin-diffusion coefficient D of hydrogen has been measured as a function of the density ? up to a maximum density of 850 amagats for various ortho-para hydrogen concentrations in the range 20-75% of orthohydrogen between 20 and 55K by the spin echo technique. Within the experimental error of 10%, the absolute value of D for the dilute gas is in agreement with the calculations of Buckingham et al. over this entire temperature range. Within this accuracy, no dependence on orthohydrogen concentration (at constant total density) is observed. The experimental results tend to confirm the conclusion of Emery, deduced from a detailed analysis of the Boltzmann diffusion equation, that symmetry effects cannot be observed in the diffusion process.

A. Hartland and M. Lipsicas

1964-02-03T23:59:59.000Z

358

Industry - ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

359

Neutron wave packet tomography  

E-Print Network [OSTI]

A tomographic technique is introduced in order to determine the quantum state of the center of mass motion of neutrons. An experiment is proposed and numerically analyzed.

G. Badurek; P. Facchi; Y. Hasegawa; Z. Hradil; S. Pascazio; H. Rauch; J. Rehacek; T. Yoneda

2005-03-29T23:59:59.000Z

360

Neutron Science Forum | ORNL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

environment for discussion, innovation, and dissemination of information within the neutron scattering community as well as engaging closely related disciplines through...

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

Neutron Science | ORNL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

User Office User Program Manager Laura Morris Edwards 865.574.2966 ORNL study uses neutron scattering, supercomputing to demystify forces at play in biofuel production Full...

362

Polarizability of the Neutron  

Science Journals Connector (OSTI)

Experiments on scattering of low-energy neutrons by heavy elements may give information concerning the electric polarizability of the neutron. The relation of the electric polarizability to the low-energy neutron scattering data is developed. One pertinent experiment is discussed and from this an upper bound on the polarizability is obtained. This upper bound to the polarizability ? is an order of magnitude larger than the meson-theoretic estimate of ?. If the value of ? is as small as is predicted by meson theory, or by an analysis of the pion photoproduction data, then it is unlikely to be observed in neutron scattering experiments of the presently achievable accuracy.

R. M. Thaler

1959-05-01T23:59:59.000Z

363

Neutron superfluidity and unusual nuclear shapes in neutron stars crusts  

Science Journals Connector (OSTI)

We calculate in the frame-work of a semiclassical model the neutron superfluidity in the crust of neutron stars, accounting for the presence of unusual....

G. Lazzari; F. V. De Blasio

1994-01-01T23:59:59.000Z

364

Neutron capture cross sections for neutron-rich isotopes  

Science Journals Connector (OSTI)

Average continuum (Hauser-Feshbach) and resonance (Breit-Wigner) neutron capture rates for neutron-rich isotopes, determined on the basis of...

B. Leist; W. Ziegert; M. Wiescher

1985-01-01T23:59:59.000Z

365

Neutron Diffraction Studies of Proteins  

Science Journals Connector (OSTI)

20 November 1980 research-article Neutron Diffraction Studies of Proteins G. A. Bentley S. A. Mason Neutrons interact differently with protein crystals...hydrogen or deuterium atoms diffract neutrons relatively more strongly, but in addition...

1980-01-01T23:59:59.000Z

366

Neutron and Nuclear Science News  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

News Recent news and events related to neutron and nuclear science at LANSCE. Neutron and Nuclear Science News Links Neutron and Nuclear Science News Media Links Profiles Events at...

367

Neutron Scattering Methods in Chemistry  

Science Journals Connector (OSTI)

Starting with basic properties of the neutron, this chapter reviews the most important neutron scattering methods that provide valuable information for a ... wide, from standard methods of crystallography to neutron

L. Pusztai

2011-01-01T23:59:59.000Z

368

Quantum states of neutrons in magnetic thin films  

SciTech Connect (OSTI)

We have studied experimentally and theoretically the interaction of polarized neutrons with magnetic thin films and magnetic multilayers. In particular, we have analyzed the behavior of the critical edges for total external reflection in both cases. For a single film we have observed experimentally and theoretically a simple behavior: the critical edges remain fixed and the intensity varies according to the angle between the polarization axis and the magnetization vector inside the film. For the multilayer case we find that the critical edges for spin-up and spin-down polarized neutrons move toward each other as a function of the angle between the magnetization vectors in adjacent ferromagnetic films. Although the results for multilayers and single thick layers appear to be different, in fact, the same spinor method explains both results. An interpretation of the critical edges behavior for the multilyers as a superposition of ferromagnetic and antifferomagnetic states is given.

Radu, F.; Zabel, H. [Department of Physics, Ruhr-University Bochum, D- 44780 Bochum (Germany); Leiner, V. [Institut fuer Werkstoffforschung WFN, GKSS Forschungszentrum GmbH, 21502 Geesthacht (Germany); Wolff, M. [Department of Physics, Ruhr-University Bochum, D- 44780 Bochum (Germany); Institut Laue-Langevin, F-38042 Grenoble Cedex 9 (France); Ignatovich, V.K. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980, Dubna Moscow Region (Russian Federation)

2005-06-01T23:59:59.000Z

369

Neutron Diffraction @ TOPAZ  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

370

Neutron electric dipole moment on the lattice  

E-Print Network [OSTI]

We carry out a feasibility study toward a lattice QCD calculation of the neutron electric dipole moment (NEDM) in the presence of the $\\theta$ term using two different approaches. In the first method, we calculate the CP-odd electromagnetic form factor $F_3$, which becomes the NEDM in the zero momentum transfer limit. At the first order in $\\theta$, we derive a formula connecting the lattice three-point function to the CP-odd electromagnetic form factor. In the second method we directly extract the NEDM from the energy difference between spin-up and spin-down neutron states in the presence of a constant electric field, without expanding a small but non-zero $\\theta$. We test both approaches numerically, employing the domain-wall quark action with the RG improved gauge action in quenched QCD at $a^{-1}\\simeq 2$ GeV on a $16^3\\times 32\\times 16$ lattice, and further applying the second method to the clover quark action at a similar lattice spacing and nucleon mass. We obtain good signals from both approaches. In particular the second method works well with both fermion formulations.

Eigo Shintani; S. Aoki; N. Ishizuka; K. Kanaya; Y. Kikukawa; Y. Kuramashi; M. Okawa; A. Ukawa; T. Yoshi

2005-09-26T23:59:59.000Z

371

Neutron activation experiments in radiochemistry  

Science Journals Connector (OSTI)

Neutron activation experiments in radiochemistry ... Describes experimentation involving the neutron activation of a variety of samples irradiated in a subcritical reactor and a paraffin-moderated source. ...

Karl S. Vorres

1960-01-01T23:59:59.000Z

372

Neutron Stars and Fractal Dimensionality  

E-Print Network [OSTI]

We argue that the material inside Neutron stars behaves anomalously with fractal statistics and that in principle, we could induce mini Neutron stars, with the release of energy.

Burra G. Sidharth

2008-05-06T23:59:59.000Z

373

A history of the neutron  

Science Journals Connector (OSTI)

A history of the neutron ... Describes some of the individuals and the work they did leading to the discovery of the neutron. ...

Vasilis Lavrakas

1952-01-01T23:59:59.000Z

374

Neutron and Nuclear Science Publications  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Publications Recent publications related to neutron and nuclear science at LANSCE. Neutron and Nuclear Science Publications Chi-Nu Publications DANCE Publications GEANIE...

375

Neutron and Nuclear Science News  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

News Recent news and events related to neutron and nuclear science at LANSCE. Neutron and Nuclear Science News Nuclear science observations and opportunities at the Los Alamos...

376

Neutron Science Research Areas | ORNL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Home | Science & Discovery | Neutron Science | Research Areas SHARE Research Areas Neutron scattering research at ORNL covers four broad research areas: biology and soft...

377

LANSCE School on Neutron Scattering:  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

11 th LANSCE School on Neutron Scattering: Materials at the Mesoscale Lujan Center Los Alamos Neutron Science Center Los Alamos National Laboratory lansce.lanl.govneutronschool...

378

Advances in specular neutron reflectometry  

Science Journals Connector (OSTI)

Specular neutron reflectometry provides a depth profile of the scattering ... material. To date, numerous productive applications of neutron reflectometry have been demonstrated. With the new development ... stil...

C.F. Majkrzak; N.F. Berk

2002-12-01T23:59:59.000Z

379

Strength of reduced two-body spin-orbit interaction from chiral three-nucleon force  

E-Print Network [OSTI]

The contribution of a chiral three-nucleon force to the strength of an effective spin-orbit coupling is estimated. We first construct a reduced two-body interaction by folding one-nucleon degrees of freedom of the three-nucleon force in nuclear matter. The spin-orbit strength is evaluated by a Scheerbaum factor obtained by the $G$-matrix calculation in nuclear matter with the two-nucleon interaction plus the reduced two-nucleon interaction. The problem of the insufficiency of modern realistic two-nucleon interactions to account for the empirical spin-orbit strength is resolved. It is also indicated that the spin-orbit coupling is weaker in the neutron-rich environment. Because the spin-orbit component from the three-nucleon force is determined by the low-energy constants fixed in the two-nucleon sector, there is little uncertainty in the present estimation.

M. Kohno

2012-09-23T23:59:59.000Z

380

Strength of reduced two-body spin-orbit interaction from chiral three-nucleon force  

E-Print Network [OSTI]

The contribution of a chiral three-nucleon force to the strength of an effective spin-orbit coupling is estimated. We first construct a reduced two-body interaction by folding one-nucleon degrees of freedom of the three-nucleon force in nuclear matter. The spin-orbit strength is evaluated by a Scheerbaum factor obtained by the $G$-matrix calculation in nuclear matter with the two-nucleon interaction plus the reduced two-nucleon interaction. The problem of the insufficiency of modern realistic two-nucleon interactions to account for the empirical spin-orbit strength is resolved. It is also indicated that the spin-orbit coupling is weaker in the neutron-rich environment. Because the spin-orbit component from the three-nucleon force is determined by the low-energy constants fixed in the two-nucleon sector, there is little uncertainty in the present estimation.

Kohno, M

2012-01-01T23:59:59.000Z

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.


381

Category:Neutron Log | Open Energy Information  

Open Energy Info (EERE)

Neutron Log page? For detailed information on Neutron Log, click here. Category:Neutron Log Add.png Add a new Neutron Log Technique Pages in category "Neutron Log" This category...

382

Bulk microstructure in a strained cohesive powder R. Andersson,1,  

E-Print Network [OSTI]

Neutron Scattering is able to characterise powders in terms of their density- density correlation function, 61.12.Ex, 81.05.Rm Keywords: Powder, Cohesion, Microstructure, Small-Angle Neutron Scattering, SESANS Resonance Imaging [5, 6]. Spin Echo Small Angle Neutron Scattering (SESANS) is using the penetrating ability

Luding, Stefan

383

Sandia National Laboratories: Spontaneous Coherence and Spin...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Spontaneous Coherence and Spin Texture Spontaneous Coherence and Spin Texture videobanner Spontaneous Coherence and Spin Texture in a Cold Exciton Gas (Watch Video) Speaker:...

384

Neutron Capture Therapy  

Science Journals Connector (OSTI)

... . Only those elements which have a high thermal-neutron capture cross-section, such as boron-10, lithium-6, and uranium-235, are useful. This suggestion was first put forward ... was first put forward in 1936 by Locher. The utilization of thermal neutron capture by boron-10 for the treatment of human-brain tumours, chiefly glioblastoma multiforme, has been under investigation ...

1961-09-23T23:59:59.000Z

385

Neutron capture therapies  

DOE Patents [OSTI]

In one embodiment there is provided an application of the .sup.10 B(n,.alpha.).sup.7 Li nuclear reaction or other neutron capture reactions for the treatment of rheumatoid arthritis. This application, called Boron Neutron Capture Synovectomy (BNCS), requires substantially altered demands on neutron beam design than for instance treatment of deep seated tumors. Considerations for neutron beam design for the treatment of arthritic joints via BNCS are provided for, and comparisons with the design requirements for Boron Neutron Capture Therapy (BNCT) of tumors are made. In addition, exemplary moderator/reflector assemblies are provided which produce intense, high-quality neutron beams based on (p,n) accelerator-based reactions. In another embodiment there is provided the use of deuteron-based charged particle reactions to be used as sources for epithermal or thermal neutron beams for neutron capture therapies. Many d,n reactions (e.g. using deuterium, tritium or beryllium targets) are very prolific at relatively low deuteron energies.

Yanch, Jacquelyn C. (Cambridge, MA); Shefer, Ruth E. (Newton, MA); Klinkowstein, Robert E. (Winchester, MA)

1999-01-01T23:59:59.000Z

386

Neutron calibration facilities  

Science Journals Connector (OSTI)

......shut down. A recent development for a thermal neutron calibration field is a neutron guide used at the research reactor GKSS Geesthacht(35). The result is a high-intensity thermal beam providing a flux of up to 106 s1 with a field size of about 2.5 2......

H. Schuhmacher

2004-08-01T23:59:59.000Z

387

The neutron skin in neutron-rich nuclei at Jefferson Lab  

SciTech Connect (OSTI)

The Jefferson Lab program to measure the symmetry energy of neutron-rich nuclear matter, using precision electroweak methods, is progressing well. The initial measurement by the PREX experiment, leading to a 2-sigma determination of the "neutron skin" in {sup 208}Pb , has been published. Design and preparation for a further, more-precise measurement on {sup 208}Pb is progressing well and there is general acceptance of the great advantage to a further measurement on {sup 48}Ca . The surprising ancillary result that the beam-normal single-spin asymmetry for {sup 208}Pb is consistent with zero is also now in the literature. This paper will discuss the current experimental situation of the program.

Dalton, Mark M. [JLAB

2013-11-01T23:59:59.000Z

388

Neutron Scattering Software  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

389

Industry - ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

390

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

391

Structure of the Neutron  

Science Journals Connector (OSTI)

In an earlier paper, the contribution of the meson current to the electromagnetic structure of the nucleon was calculated by use of the dispersion relations for pion-nucleon scattering. Here the contribution of the nucleon current to the electromagnetic structure of the neutron is obtained analogously by use of the dispersion relations for neutron-proton scattering. Only the contribution from the one-pion and two-pion states of nucleon-nucleon scattering is considered. It is found that both states reduce the neutron-electron potential, i.e., leads to a smaller charge radius of the neutron. The contribution from the deuteron state is shown to be negligible. The resulting mean-square radii of the neutron, including the contributions of both meson and nucleon current, are (0.2310-13cm)2 for the charge distribution and (0.4110-13cm)2 for the magnetic moment distribution with f2=0.08.

Katsumi Tanaka

1959-01-15T23:59:59.000Z

392

THERMAL NEUTRON BACKSCATTER IMAGING.  

SciTech Connect (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

393

SINGLE CRYSTAL NEUTRON DIFFRACTION.  

SciTech Connect (OSTI)

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

394

Electron Spin Decoherence in Silicon Carbide Nuclear Spin Bath  

E-Print Network [OSTI]

In this paper, we study the electron spin decoherence of single defects in silicon carbide (SiC) nuclear spin bath. We find that, although the natural abundance of $^{29}\\rm{Si}$ ($p_{\\rm{Si}}=4.7\\%$) is about 4 times larger than that of $^{13}{\\rm C}$ ($p_{\\rm{C}}=1.1\\%$), the electron spin coherence time of defect centers in SiC nuclear spin bath in strong magnetic field ($B>300~\\rm{Gauss}$) is longer than that of nitrogen-vacancy (NV) centers in $^{13}{\\rm C}$ nuclear spin bath in diamond. The reason for this counter-intuitive result is the suppression of heteronuclear-spin flip-flop process in finite magnetic field. Our results show that electron spin of defect centers in SiC are excellent candidates for solid state spin qubit in quantum information processing.

Li-Ping Yang; Christian Burk; Mattias Widmann; Sang-Yun Lee; Jrg Wrachtrup; Nan Zhao

2014-09-16T23:59:59.000Z

395

Spin-Charge Separation in the Quantum Spin Hall State  

Science Journals Connector (OSTI)

The quantum spin Hall state is a topologically nontrivial insulator state protected by the time-reversal symmetry. We show that such a state always leads to spin-charge separation in the presence of a ? flux. Our result is generally valid for any interacting system. We present a proposal to experimentally observe the phenomenon of spin-charge separation in the recently discovered quantum spin Hall system.

Xiao-Liang Qi and Shou-Cheng Zhang

2008-08-19T23:59:59.000Z

396

On the kinematics and resolution of spectrometers for neutron Brillouin scattering  

SciTech Connect (OSTI)

Neutron Brillouin scattering involves measurement of excitations at smaller Q values than in currently customary. We outline the kinematic constraints on scattering angle and incident energy for excitations with both linear dispersion (sound waves) and parabolic dispersion (ferromagnetic spin waves), and discuss the resolution characteristics of the chopper spectrometer proposed for LANSCE which should be suitable for such studies. In particular, we demonstrate that longitudinal resolution focusing can be exploited both in neutron energy gain and in neutron energy loss. 13 refs., 8 figs., 1 tab.

Robinson, R.A.

1988-01-01T23:59:59.000Z

397

Meteorological significance of frontal thin-line angel echoes observed by CPS-9 radar  

E-Print Network [OSTI]

Effects of Vertical Wind-Shear on Convection Cells in the Atmosphere and Ocean 83 86 C. Radar Observations of Benard Cells and the Effects of Vertical Wind-Shear 89 D. Possible Effects of Wind-Shear Modified Convection Cells Exhibited by the Angel... of the Relationship between Wind-shear and Angel Echo Patterns 102 D. Summary of Conclusions REFERENCES APPENDIX 103 105 110 LIST OF FIGURES Figure 1. Surface Nap, 1500C, 10 December 1957 2. PPI Photographs~ 10 December 1957 3. Cold-frontal and Thin...

Miller, Donald Bradford

2012-06-07T23:59:59.000Z

398

Anomalous decay of photon echo in a quantum dot ensemble in the strong excitation regime  

SciTech Connect (OSTI)

We investigated the coherent dynamics of exciton ground-state transitions in an 150-layer-stacked strain-compensated InAs quantum dot ensemble using photon echo (PE) technique in the strong excitation regime. The time delay dependence of PE signal intensity shows a drastic change depending on the excitation intensity and the aperture position placed in front of a detector. Our results suggest that the excitation-intensity-dependent spatial distribution of PE signal intensity plays an important role in observing PE signal decay in the strong excitation regime.

Suemori, Ryosuke; Ishi-Hayase, Junko [Department of Applied Physics and Physico-Informatics, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522 (Japan); Akahane, Kouichi; Yamamoto, Naokatsu [National Institute of Information and Communications Technology (NICT), 4-2-1, Nukuikitamchi, Koganei, Tokyo 102-8554 (Japan)

2013-12-04T23:59:59.000Z

399

Generation of high-power tunable terahertz-radiation by nonrelativistic beam-echo harmonic effect  

SciTech Connect (OSTI)

A new type of terahertz radiation source based on the nonrelativistic electron beam-wave interaction is proposed. Here, the beam echo harmonic effect is applied to a traveling wave tube like device. The scheme is configured as a combination of a frequency multiplier and amplifier with, for instance, W-band (millimeter wave) input signals and terahertz output power. A one-dimensional model of this device shows that a 10th order harmonic-wave can be generated while other harmonic waves are suppressed. The device only requires a readily available input source (W-band), and the output frequency can be tuned continuously over a wide band.

Gong Huarong; Xu Jin; Wei Yanyu; Gong Yubin [National Key Laboratory of Science and Technology on Vacuum Electronics, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China); Travish, Gil [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States); Feng Jinjun [Vacuum Electronics National Laboratory, Vacuum Electronics research Institute, Beijing 100016 (China)

2013-01-15T23:59:59.000Z

400

Coherent optical polarization of bulk GaAs studied by femtosecond photon-echo spectroscopy  

Science Journals Connector (OSTI)

The nonlinear polarization close to the band gap of GaAs is studied by spectrally and temporally resolved four-wave mixing. Excitonic and free carrier contributions both excited within the bandwidth of the 100 fs pulses are distinguished for the first time. The excitonic part dominates at carrier densities below 1016 cm-3. At higher density, nonthermalized free carriers give rise to an additional component resonant to the pulse that shows a photon-echo-like time behavior. Monte Carlo simulations including the coherent polarization and the scattering dynamics of the carriers account for the data.

A. Lohner; K. Rick; P. Leisching; A. Leitenstorfer; T. Elsaesser; T. Kuhn; F. Rossi; W. Stolz

1993-07-05T23:59:59.000Z

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

Hanford Tank Farms Waste Feed Flow Loop Phase VI: PulseEcho System Performance Evaluation  

SciTech Connect (OSTI)

This document presents the visual and ultrasonic PulseEcho critical velocity test results obtained from the System Performance test campaign that was completed in September 2012 with the Remote Sampler Demonstration (RSD)/Waste Feed Flow Loop cold-test platform located at the Monarch test facility in Pasco, Washington. This report is intended to complement and accompany the report that will be developed by WRPS on the design of the System Performance simulant matrix, the analysis of the slurry test sample concentration and particle size distribution (PSD) data, and the design and construction of the RSD/Waste Feed Flow Loop cold-test platform.

Denslow, Kayte M.; Bontha, Jagannadha R.; Adkins, Harold E.; Jenks, Jeromy WJ; Hopkins, Derek F.

2012-11-21T23:59:59.000Z

402

Quantum spin dynamics  

E-Print Network [OSTI]

The classical Landau-Lifshitz equation has been derived from quantum mechanics. Starting point is the assumption of a non-Hermitian Hamilton operator to take the energy dissipation into account. The corresponding quantum mechanical time dependent Schr\\"odinger, Liouville and Heisenberg equation have been described and the similarities and differences between classical and quantum mechanical spin dynamics have been discussed. Furthermore, a time dependent Schr\\"odinger equation corresponding to the classical Landau-Lifshitz-Gilbert equation and two ways to include temperature into the quantum mechanical spin dynamics have been proposed.

Robert Wieser

2014-10-23T23:59:59.000Z

403

RHIC Spin Program Goals of RHIC Spin Program  

E-Print Network [OSTI]

longitudinal polarization · polarized atomic hydrogen jet target Installed and commissioned during run 4 violating production of W± · Transverse spin: Transversity () & transverse spin effects with connections to orbital angular momentum (Ly) #12;5/11/2006 L.C.Bland, DOE Review of MEP 5 Methods to Address Spin

404

Gravitational Waveforms for Precessing, Quasicircular Compact Binaries with Multiple Scale Analysis: Small Spin Expansion  

E-Print Network [OSTI]

We obtain analytical gravitational waveforms in the frequency-domain for precessing, quasi-circular compact binaries with small spins, applicable, for example, to binary neutron star inspirals. We begin by calculating an analytic solution to the precession equations, obtained by expanding in the dimensionless spin parameters and using multiple-scale analysis to separate timescales. We proceed by analytically computing the Fourier transform of time-domain waveform through the stationary phase approximation. We show that the latter is valid for systems with small spins. Finally, we show that these waveforms have a high overlap with numerical waveforms obtained through direct integration of the precession equations and discrete Fourier transformations. The resulting, analytic waveform family is ideal for detection and parameter estimation of gravitational waves emitted by inspiraling binary neutron stars with ground-based detectors.

Katerina Chatziioannou; Antoine Klein; Nicolas Yunes; Neil Cornish

2013-07-16T23:59:59.000Z

405

Magnetic structure and spin excitations in BaMn2Bi2  

SciTech Connect (OSTI)

We present a single crystal neutron scattering study of BaMn2Bi2, a recently synthesized material with the same ThCr2Si2-type structure found in several Fe-based unconventional superconducting materials. We show long range magnetic order, in the form of a G-type antiferromagnetic structure, to exist up to 390 K with an indication of a structural transition at 100 K. Utilizing inelastic neutron scattering we observe a spin-gap of 16 meV, with spin-waves extending up to 55 meV. We find these magnetic excitations are well fit to a J1-J2-Jc Heisenberg model and present values for the exchange interactions. The spin wave spectrum appears to be unchanged by the 100 K structural phase transition.

Calder, Stuart A [ORNL; Saparov, Bayrammurad I [ORNL; Niedziela, Jennifer L [ORNL; Lumsden, Mark D [ORNL; Safa-Sefat, Athena [ORNL; Christianson, Andrew D [ORNL

2014-01-01T23:59:59.000Z

406

Transverse Spin Physics: Recent Developments  

SciTech Connect (OSTI)

Transverse-spin physics has been very active and rapidly developing in the last few years. In this talk, I will briefly summarize recent theoretical developments, focusing on the associated QCD dynamics in transverse spin physics.

Yuan, Feng

2008-12-10T23:59:59.000Z

407

Neutron LifetimeNeutron Lifetime IUCF Colloquium April 13,  

E-Print Network [OSTI]

Neutron LifetimeNeutron Lifetime IUCF Colloquium April 13, 2007 Albert Steyerl Department 940 878.5±0.8 885.7±0.8 new result neutronlifetime(),s year world average Neutron lifetime data #12 world average Neutron lifetime data A. Serebrov et al. 2005Storage of ultra-cold neutrons878.5 ±±±± 0

Steyerl, Albert

408

Hyperons in neutron stars  

E-Print Network [OSTI]

Using the Dirac-Brueckner-Hartree-Fock approach, the properties of neutron-star matter including hyperons are investigated. In the calculation, we consider both time and space components of the vector self-energies of baryons as well as the scalar ones. Furthermore, the effect of negative-energy states of baryons is partly taken into account. We obtain the maximum neutron-star mass of $2.08\\,M_{\\odot}$, which is consistent with the recently observed, massive neutron stars. We discuss a universal, repulsive three-body force for hyperons in matter.

Katayama, Tetsuya

2015-01-01T23:59:59.000Z

409

ACCELERATION INDUCED SPIN AND  

E-Print Network [OSTI]

spin at each event. A unique and natural law of parallel transport of quantum states between different mechanical line of reasoning leads to the heuristic con* *clusion that gravitation is to be identified AND ITS GAUGE GEOMETRY The line of reasoning which lies at the base of Einstein's gravitation the

Gerlach, Ulrich

410

Muon spin rotation  

Science Journals Connector (OSTI)

... vast funding accorded high energy physics research in recent years.?SR-the acronym stands for Muon Spin Rotation, Relaxation, Resonance, Research or what have you, and refers to the ... the most promising new work related to purely chemical problems. Indeed, the use of muons in chemistry is striking not only for providing yet another probe of chemical systems, ...

G. C. Stirling

1978-11-23T23:59:59.000Z

411

Relativistic viscous hydrodynamics for heavy-ion collisions with ECHO-QGP  

E-Print Network [OSTI]

We present ECHO-QGP, a numerical code for $(3+1)$-dimensional relativistic viscous hydrodynamics designed for the modeling of the space-time evolution of the matter created in high energy nuclear collisions. The code has been built on top of the \\emph{Eulerian Conservative High-Order} astrophysical code for general relativistic magneto-hydrodynamics [\\emph{Del Zanna et al., Astron. Astrophys. 473, 11, 2007}] and here it has been upgraded to handle the physics of the Quark-Gluon Plasma. ECHO-QGP features second-order treatment of causal relativistic viscosity effects in both Minkowskian or Bjorken coordinates; partial or complete chemical equilibrium of hadronic species before kinetic freeze-out; initial conditions based on the optical Glauber model, including a Monte-Carlo routine for event-by-event fluctuating initial conditions; a freeze-out procedure based on the Cooper-Frye prescription. The code is extensively validated against several test problems and results always appear accurate, as guaranteed by th...

Del Zanna, L; Inghirami, G; Rolando, V; Beraudo, A; De Pace, A; Pagliara, G; Drago, A; Becattini, F

2013-01-01T23:59:59.000Z

412

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

SciTech Connect (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

413

Neutron Stars Properties and Crust Movements in Post-glitch Epoch  

E-Print Network [OSTI]

Using a new numerical code with non-uniform adapted mesh, we study the changes produced in the global properties of neutron stars by the motion of matter in crust region during post-glitch epoch. Our numerical analysis shows that these changes may contribute to explain the observed spin-down of rotational frequency.

L. M. Gonzlez-Romero; F. Navarro-Lrida

2009-02-07T23:59:59.000Z

414

Industry - ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

415

Education | ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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).

416

ORNL Neutron Sciences Instruments  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

417

Pulsed Neutron Powder Diffraction  

Science Journals Connector (OSTI)

The nature and scope of powder diffraction with a white, pulsed beam of neutrons is discussed. Analysis of the data by the Rietveld profile technique is described in brief, and a range of applications in solid...

A. K. Cheetham

1988-01-01T23:59:59.000Z

418

Neutron Science Center  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

to have rare opportunity to tour Neutron Science Center May 10, 2011 LANL Rosenfest will celebrate life of LANSCE founder Louis Rosen and offer tour LOS ALAMOS, New Mexico, May 10,...

419

Shifting scintillator neutron detector  

DOE Patents [OSTI]

Provided are sensors and methods for detecting thermal neutrons. Provided is an apparatus having a scintillator for absorbing a neutron, the scintillator having a back side for discharging a scintillation light of a first wavelength in response to the absorbed neutron, an array of wavelength-shifting fibers proximate to the back side of the scintillator for shifting the scintillation light of the first wavelength to light of a second wavelength, the wavelength-shifting fibers being disposed in a two-dimensional pattern and defining a plurality of scattering plane pixels where the wavelength-shifting fibers overlap, a plurality of photomultiplier tubes, in coded optical communication with the wavelength-shifting fibers, for converting the light of the second wavelength to an electronic signal, and a processor for processing the electronic signal to identify one of the plurality of scattering plane pixels as indicative of a position within the scintillator where the neutron was absorbed.

Clonts, Lloyd G; Cooper, Ronald G; Crow, Jr., Morris Lowell; Hannah, Bruce W; Hodges, Jason P; Richards, John D; Riedel, Richard A

2014-03-04T23:59:59.000Z

420

Scattering of Slow Neutrons  

Science Journals Connector (OSTI)

1 September 1937 research-article Scattering of Slow Neutrons M. Goldhaber G. H. Briggs The Royal Society is collaborating with JSTOR to digitize, preserve, and extend access to Proceedings...

1937-01-01T23:59:59.000Z

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.


421

Neutron Diffraction Texture Analysis  

Science Journals Connector (OSTI)

...conducted at Chalk River (Canada), Geesthacht (Germany), LLB (France) and NIST...deformed limestone that was measured at Geesthacht with this method. It is also possible...with monochromatic neutrons at GKSS, Geesthacht. Equal area projection, linear contours...

Hans-Rudolf Wenk

422

Neutron stars - thermal emitters  

E-Print Network [OSTI]

Confronting theoretical models with observations of thermal radiation emitted by neutron stars is one of the most important ways to understand the properties of both, superdense matter in the interiors of the neutron stars and dense magnetized plasmas in their outer layers. Here we review the theory of thermal emission from the surface layers of strongly magnetized neutron stars, and the main properties of the observational data. In particular, we focus on the nearby sources for which a clear thermal component has been detected, without being contaminated by other emission processes (magnetosphere, accretion, nebulae). We also discuss the applications of the modern theoretical models of the formation of spectra of strongly magnetized neutron stars to the observed thermally emitting objects.

Potekhin, A Y; Pons, J A

2014-01-01T23:59:59.000Z

423

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.

424

Data Analysis & Visualization | Neutron Science | ORNL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Neutron Data Analysis and Visualization SHARE Neutron Data Analysis and Visualization As the data sets generated by the increasingly powerful neutron scattering instruments at HFIR...

425

Science Education Programs | Neutron Science | ORNL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

with Neutrons Graduate & Post-doctoral Programs Student & Teacher Programs Science Forum Neutron Scattering Tutorials Kids' Corner NScD Careers Supporting Organizations Neutron...

426

Fast Pulsing Neutron Generators for Security Application  

E-Print Network [OSTI]

FAST PULSING NEUTRON GENERATORS FOR SECURITY APPLICATION* Q.time/fast pulsing neutron generator is needed primarily forA compact neutron generator, currently being developed in

Ji, Q.

2010-01-01T23:59:59.000Z

427

Leading neutron spectra  

E-Print Network [OSTI]

It is shown that the observation of the spectra of leading neutrons from proton beams can be a good probe of absorptive and migration effects. We quantify how these effects modify the Reggeized pion-exchange description of the measurements of leading neutrons at HERA. We are able to obtain a satisfactory description of all the features of these data. We also briefly discuss the corresponding data for leading baryons produced in hadron-hadron collisions.

A. B. Kaidalov; V. A. Khoze; A. D. Martin; M. G. Ryskin

2006-02-23T23:59:59.000Z

428

COS DCE BOOT FSW v1.09 Component Test Results Requirement 5.2.3.2 Echoes for Command Opcode and Parameters  

E-Print Network [OSTI]

COS DCE BOOT FSW v1.09 Component Test Results Requirement 5.2.3.2 Echoes for Command Opcode. Brownsberger 2-13-01 The Center for Astrophysics and Space Astronomy Reviewed: Approved: COS DCE BOOT FSW v1 & Space Astronomy Initial Release COS DCE BOOT FSW v1.09 Component Test Results Requirement 5.2.3.2 Echoes

Colorado at Boulder, University of

429

COS DCE BOOT FSW v1.13 Component Test Results Requirement 5.2.3.2 Echoes for Command Opcode and Parameters  

E-Print Network [OSTI]

COS DCE BOOT FSW v1.13 Component Test Results Requirement 5.2.3.2 Echoes for Command Opcode. Brownsberger 2-13-01 The Center for Astrophysics and Space Astronomy Reviewed: Approved: COS DCE BOOT FSW v1 & Space Astronomy Initial Release COS DCE BOOT FSW v1.13 Component Test Results Requirement 5.2.3.2 Echoes

Colorado at Boulder, University of

430

Neutron Radii in Nuclei and the Neutron Equation of State  

Science Journals Connector (OSTI)

The root-mean-square radius for neutrons in nuclei is investigated in the Skyrme Hartree-Fock model. The main source of theoretical variation comes from the exchange part of the density-dependent interaction which can be related to a basic property of the neutron equation of state. A precise measurement of the neutron radius in 208Pb would place an important new constraint on the equation of state for neutron matter. The Friedman-Pandharipande neutron equation of state would lead to a very precise value of 0.160.02 fm for the difference between the neutron and the proton root-mean-square radius in 208Pb.

B. Alex Brown

2000-12-18T23:59:59.000Z

431

Magnetic excitations in Dy/Y superlattices as seen via inelastic neutron scattering  

Science Journals Connector (OSTI)

Measurements of the spin excitations propagating normal to the interfaces in Dy/Y superlattices using neutron inelastic scattering are presented. For a given magnon momentum, a neutron-scattering spectrum shows multiple peaks at different energies, which indicates discrete energy spectra. The results are compared with theoretical calculations developed here to describe magnetic excitations in rare-earth superlattices. The theory accounts for Ruderman-Kittel-Kasuya-Yosida (RKKY) and Dzyaloshinsky-Moriya interactions in incommensurate helicoidal structures and achieves a quantitative agreement with the experimental data. This work demonstrates that neutron inelastic scattering can be used for systematic studies of the exchange interactions and spin dynamics in nanomagnetic systems over wide areas of the Brillouin zone.

A. T. D. Grnwald; A. R. Wildes; W. Schmidt; E. V. Tartakovskaya; J. Kwo; C. Majkrzak; R. C. C. Ward; A. Schreyer

2010-07-23T23:59:59.000Z

432

Deeply virtual compton scattering from the neutron with CLAS and CLAS12  

SciTech Connect (OSTI)

Generalised Parton Distributions (GPDs) offer an insight into the three-dimensional structure of the nucleon and its internal dynamics, relating the longitudinal momentum of quarks to their transverse position. A very effective means of accessing GPDs is via measurements of cross-sections and polarisation-asymmetries in Deeply Virtual Compton Scattering (DVCS). In particular, the beam-spin asymmetry (BSA) in DVCS from the neutron is especially sensitive to angular momentum of the up- and down-quarks, and its measurement therefore has potential to shed important light on the puzzle of nucleon spin. We present a preliminary extraction of BSA from a recent experiment using a 6 GeV electron beam and the CLAS detector at Jefferson Laboratory and introduce the Central Neutron Detector to be integrated with CLAS12 for the exclusive measurement of neutron DVCS at 11 GeV, made possible by the Jefferson Lab upgrade.

Sokhan, Daria [Glasgow University, Glasgow, Scotland (United Kingdom)

2014-01-01T23:59:59.000Z

433

RELATIONS BETWEEN NEUTRON-STAR PARAMETERS IN THE HARTLE-THORNE APPROXIMATION  

SciTech Connect (OSTI)

Using stellar structure calculations in the Hartle-Thorne approximation, we derive analytic expressions connecting the ellipticity of the stellar surface to the compactness, the spin angular momentum, and the quadrupole moment of the spacetime. We also obtain empirical relations between the compactness, the spin angular momentum, and the spacetime quadrupole. Our formulae reproduce the results of numerical calculations to within a few percent and help reduce the number of parameters necessary to model the observational appearance of moderately spinning neutron stars. This is sufficient for comparing theoretical spectroscopic and timing models to observations that aim to measure the masses and radii of neutron stars and to determine the equation of state prevailing in their interiors.

Baubck, Michi; Psaltis, Dimitrios; zel, Feryal [Astronomy Department, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Berti, Emanuele, E-mail: mbaubock@email.arizona.edu, E-mail: dpsaltis@email.arizona.edu, E-mail: fozel@email.arizona.edu, E-mail: berti@phy.olemiss.edu [Department of Physics and Astronomy, The University of Mississippi, University, MS 38677 (United States)

2013-11-01T23:59:59.000Z

434

Estimation of quantum correlations in magnetic materials by neutron scattering data  

Science Journals Connector (OSTI)

Abstract We demonstrate that inelastic neutron scattering technique can be used to indirectly detect and measure the macroscopic quantum correlations quantified by both entanglement and discord in a quantum magnetic material, VODPO 4 ? 1 2 D 2 O . The amount of quantum correlations is obtained by analyzing the neutron scattering data of magnetic excitations in isolated V4+ spin dimers. Our quantitative analysis shows that the critical temperature of this material can reach as high as T c = 82.5 K , where quantum entanglement drops to zero. Significantly, quantum discord can even survive at T c = 300 K and may be used in room temperature quantum devices. Taking into account the spinorbit (SO) coupling, we also predict theoretically that entanglement can be significantly enhanced and the critical temperature T c increases with the strength of spinorbit coupling.

Ben-Qiong Liu; Lian-Ao Wu; Guo-Mo Zeng; Jian-Ming Song; Wei Luo; Yang Lei; Guang-Ai Sun; Bo Chen; Shu-Ming Peng

2014-01-01T23:59:59.000Z

435

Quantum correlations in bulk properties of solids obtained from neutron scattering  

E-Print Network [OSTI]

We demonstrate that inelastic neutron scattering technique can be used to indirectly detect and measure the macroscopic quantum correlations quantified by both entanglement and discord in a quantum magnetic material, VODPO4 . 1D2O. The amount of quantum correlations is obtained 2 by analyzing the neutron scattering data of magnetic excitations in isolated V4+ spin dimers. Our quantitative analysis shows that the critical temperature of this material can reach as high as Tc = 82.5 K, where quantum entanglement drops to zero. Significantly, quantum discord can even survive at Tc = 300 K and may be used in room temperature quantum devices. Taking into account the spin-orbit (SO) coupling, we also predict theoretically that entanglement can be significantly enhanced and the critical temperature Tc increases with the strength of spin-orbit coupling.

Ben-Qiong Liu; Lian-Ao Wu; Guo-Mo Zeng; Jian-Ming Song; Wei Luo; Yang Lei; Guang-Ai Sun; Bo Chen; Shu-Ming Peng

2014-07-02T23:59:59.000Z

436

Neutron-Neutron Scattering at Low Energies  

Science Journals Connector (OSTI)

This paper investigates the information contained in a neutron-neutron scattering experiment at low energies which could be performed by colliding beams coming from an underground nuclear explosion. The significance of such an experiment is discussed from the point of view of a check on charge symmetry and charge independence, and it is found that because of the electromagnetic complications in proton-proton scattering, and because of the proton-neutron mass difference, the knowledge of neutron-neutron scattering would be of considerable value. The functional form of the experimental data which is most convenient for analysis and the approximate relative magnitude of the terms is investigated, and it is concluded that for the kind of experiment which is envisaged (measuring cross sections to 10% from 20 keV to 2 MeV) only two parameters should be kept in the effective-range expansion. The connection between the number and distribution of energies at which the cross section is measured and the error on the individual measurements, on the one hand, and the accuracy of the effective-range parameters deduced from the experiments, on the other, is given explicitly and is found also to depend on the absolute magnitude of the scattering length. The results show that ten 10% measurements, suitably distributed between 20 keV and 2 MeV, can determine the sign of the scattering length to four standard deviations, the magnitude of the effective range to 50-70%, and the magnitude of the scattering length to about 3%. Finally, the relationship between the variation of the effective-range parameters and the corresponding variation in the parameters of the scattering potential is studied, and it is found that, while this relationship is strongly shape-dependent, a small change in the potential parameters, in any case, results in a large change in the scattering length, but a small one in the effective range. Numerical relationships show that, even in the worst case, the variation in the scattering length is about eight times the variation in the potential parameter. It is concluded that a 10% experiment at 20 energies between 20 keV and 2 MeV would be able to get information on the potential parameters sufficiently accurately so that charge-dependent or charge-symmetry violating effects could be detected.

Michael J. Moravcsik

1964-11-09T23:59:59.000Z

437

Nuclear spin circular dichroism  

SciTech Connect (OSTI)

Recent years have witnessed a growing interest in magneto-optic spectroscopy techniques that use nuclear magnetization as the source of the magnetic field. Here we present a formulation of magnetic circular dichroism (CD) due to magnetically polarized nuclei, nuclear spin-induced CD (NSCD), in molecules. The NSCD ellipticity and nuclear spin-induced optical rotation (NSOR) angle correspond to the real and imaginary parts, respectively, of (complex) quadratic response functions involving the dynamic second-order interaction of the electron system with the linearly polarized light beam, as well as the static magnetic hyperfine interaction. Using the complex polarization propagator framework, NSCD and NSOR signals are obtained at frequencies in the vicinity of optical excitations. Hartree-Fock and density-functional theory calculations on relatively small model systems, ethene, benzene, and 1,4-benzoquinone, demonstrate the feasibility of the method for obtaining relatively strong nuclear spin-induced ellipticity and optical rotation signals. Comparison of the proton and carbon-13 signals of ethanol reveals that these resonant phenomena facilitate chemical resolution between non-equivalent nuclei in magneto-optic spectra.

Vaara, Juha, E-mail: juha.vaara@iki.fi [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014 Oulu (Finland)] [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014 Oulu (Finland); Rizzo, Antonio [Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche (IPCF-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa (Italy)] [Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche (IPCF-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa (Italy); Kauczor, Joanna; Norman, Patrick [Department of Physics, Chemistry and Biology, Linkping University, S-58183 Linkping (Sweden)] [Department of Physics, Chemistry and Biology, Linkping University, S-58183 Linkping (Sweden); Coriani, Sonia, E-mail: coriani@units.it [Dipartimento di Scienze Chimiche e Farmaceutiche, Universit degli Studi di Trieste, Via L. Giorgieri 1, I-34127 Trieste (Italy)] [Dipartimento di Scienze Chimiche e Farmaceutiche, Universit degli Studi di Trieste, Via L. Giorgieri 1, I-34127 Trieste (Italy)

2014-04-07T23:59:59.000Z

438

Depth Profile of Uncompensated Spins in an Exchange-Bias System  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

439

Depth Profile of Uncompensated Spins in an Exchange-Bias System  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

440

Depth Profile of Uncompensated Spins in an Exchange-Bias System  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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.

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

Existence of exotic torus configuration in high-spin excited states of $^{40}$Ca  

E-Print Network [OSTI]

We investigate the possibility of the existence of the exotic torus configuration in the high-spin excited states of $^{40}$Ca. We here consider the spin alignments about the symmetry axis. To this end, we use a three-dimensional cranked Skyrme Hartree-Fock method and search for stable single-particle configurations. We find one stable state with the torus configuration at the total angular momentum $J=$ 60 $\\hbar$ and an excitation energy of about 170 MeV in all calculations using various Skyrme interactions. The total angular momentum J=60 $\\hbar$ consists of aligned 12 nucleons with the orbital angular momenta $\\Lambda=+4$, +5, and +6 for spin up-down neutrons and protons. The obtained results strongly suggest that a macroscopic amount of circulating current breaking the time-reversal symmetry emerges in the high-spin excited state of $^{40}$Ca.

T. Ichikawa; J. A. Maruhn; N. Itagaki; K. Matsuyanagi; P. -G. Reinhard; S. Ohkubo

2012-07-26T23:59:59.000Z

442

Neutron degeneracy and plasma physics effects on radiative neutron captures in neutron star crust  

Science Journals Connector (OSTI)

We consider the astrophysical reaction rates for radiative neutron capture reactions (n,?) in the crust of a neutron star. The presence of degenerate neutrons at high densities (mainly in the inner crust) can drastically affect the reaction rates. Standard rates assuming a Maxwell-Boltzmann distribution for neutrons can underestimate the rates by several orders of magnitude. We derive simple analytical expressions for reaction rates at a variety of conditions with account for neutron degeneracy. We also discuss the plasma effects on the outgoing radiative transition channel in neutron radiative capture reactions and show that these effects can also increase the reaction rates by a few orders of magnitude. In addition, using detailed balance, we analyze the effects of neutron degeneracy and plasma physics on reverse (?,n) photodisintegration. We discuss the dependence of the reaction rates on temperature and neutron chemical potential and outline the efficiency of these reactions in the neutron star crust.

P. S. Shternin; M. Beard; M. Wiescher; D. G. Yakovlev

2012-07-24T23:59:59.000Z

443

Neutron-deuteron breakup reaction as a tool for studying neutron-neutron interactions  

SciTech Connect (OSTI)

An analysis of the most recent data on the reaction nd {yields} pnn revealed a serious discrepancy between theoretical predictions and cross sections measured for this reaction in various configurations where the role of neutron-neutron interactions is important. In view of this, it seems necessary both to develop theoretical approaches and to obtain new experimental data. For this purpose, a setup for studying the neutron-deuteron breakup reaction was created at the Institute for Nuclear Research on the basis of the neutron beam in the RADEX channel and deuterium targets. This facility makes it possible to perform experiments over a broad region of primary-neutron energies (10-60 MeV) and in various (final-state interaction, quasifree scattering, and spatial-star) configurations. Preliminary results of the respective experiment were obtained for configurations of final-state neutron-neutron interaction and quasifree neutron-neutron scattering.

Konobeevski, E. S., E-mail: konobeev@inr.ru; Zuyev, S. V.; Mordovskoy, M. V.; Potashev, S. I.; Sharapov, I. M. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)] [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)

2013-11-15T23:59:59.000Z

444

Spin-bus concept of spin quantum computing  

SciTech Connect (OSTI)

We present a spin-bus concept of quantum computing where an electron spin S=1/2 acts as a bus qubit connected to a finite number N of nuclear spins I=1/2 serving as client qubits. Spin-bus clusters are considered as local processing units and may be interconnected with other spin-bus clusters via electron-electron coupling in a scaled up version. Here we lay the ground for the basic functional unit with long qubit registers, provide the theory and experimental verification of correlated qubit states, and demonstrate the Deutsch algorithm. Experiments were performed on a qubyte plus one nuclear spin in a solid state system.

Mehring, Michael; Mende, Jens [2. Physikalisches Institut, University of Stuttgart (Germany)

2006-05-15T23:59:59.000Z

445

Evolution of Spin-Wave Excitations in Ferromagnetic Metallic Manganites  

SciTech Connect (OSTI)

Neutron scattering results are presented for spin-wave excitations of three ferromagnetic metallic A1xA0xMnO3 manganites (where A and A0 are rare- and alkaline-earth-metal ions), which when combined with previous work elucidate the systematics of the interactions as a function of carrier concentration x, on-site disorder, and strength of the lattice distortion. The long-wavelength spin dynamics show only a very weak dependence across the series. The ratio of fourth to first neighbor exchange (J4=J1) that controls the zone boundary magnon softening changes systematically with x, but does not depend on the other parameters. None of the prevailing models can account for these behaviors.

Ye, Feng [ORNL; Dai, Pengcheng [ORNL; Fernandez-Baca, Jaime A [ORNL; Sha, Hao [Florida International University, Miami; Lynn, J. W. [National Institute of Standards and Technology (NIST); Kawano-Furukawa, H. [Ochanomizu University, Japan; Tomioka, Y. [Correlated Electron Research Center (CERC), Japan; Tokura, Y. [University of Tokyo, Tokyo, Japan; Zhang, Jiandi [Florida International University, Miami

2006-01-01T23:59:59.000Z

446

Evolution of Spin-Wave Excitations in Ferromagnetic Metallic Manganites  

SciTech Connect (OSTI)

Neutron scattering results are presented for spin-wave excitations of three ferromagnetic metallic A{sub 1-x}A{sub x}{sup '}MnO{sub 3} manganites (where A and A{sup '} are rare- and alkaline-earth-metal ions), which when combined with previous work elucidate the systematics of the interactions as a function of carrier concentration x, on-site disorder, and strength of the lattice distortion. The long-wavelength spin dynamics show only a very weak dependence across the series. The ratio of fourth to first neighbor exchange (J{sub 4}/J{sub 1}) that controls the zone boundary magnon softening changes systematically with x, but does not depend on the other parameters. None of the prevailing models can account for these behaviors.

Ye, F. [Center for Neutron Scattering, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393 (United States); Dai Pengcheng [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996-1200 (United States); Center for Neutron Scattering, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393 (United States); Fernandez-Baca, J.A. [Center for Neutron Scattering, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393 (United States); Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996-1200 (United States); Sha Hao; Zhang Jiandi [Department of Physics, Florida International University, Miami, Florida 33199 (United States); Lynn, J.W. [NIST Center for Neutron Research, Gaithersburg, Maryland 20899 (United States); Kawano-Furukawa, H. [Department of Physics, Ochanomizu University, Bunkyo-ku, Tokyo 112-8610 (Japan); Tomioka, Y. [Correlated Electron Research Center (CERC), Tsukuba 305-0046 (Japan); Tokura, Y. [Correlated Electron Research Center (CERC), Tsukuba 305-0046 (Japan); Department of Applied Physics, University of Tokyo, Tokyo 113-8656 (Japan)

2006-02-03T23:59:59.000Z

447

Accelerated Short-TE 3D Proton Echo-Planar Spectroscopic Imaging Using 2D-SENSE with  

E-Print Network [OSTI]

Accelerated Short-TE 3D Proton Echo-Planar Spectroscopic Imaging Using 2D-SENSE with a 32-Channel times and 2D acceleration with a large array coil is expected to provide high acceleration capability using a 32-channel array coil can be accelerated 8-fold (R 4 2) along y-z to achieve a minimum

448

Predicting the Remaining Useful Lifetime of a Proton Exchange Membrane Fuel Cell using an Echo State Network  

E-Print Network [OSTI]

1 Predicting the Remaining Useful Lifetime of a Proton Exchange Membrane Fuel Cell using an Echo industrial Fuel Cell (FC) application resides in the system limited useful lifetime. Consequently, it Membrane Fuel Cell using an iterative predictive structure, which is the most common approach performing

Boyer, Edmond

449

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

450

Novel neutron focusing mirrors for compact neutron sources  

E-Print Network [OSTI]

We demonstrated neutron beam focusing and neutron imaging using axisymmetric optics, based on pairs of confocal ellipsoid and hyperboloid mirrors. Such systems, known as Wolter mirrors, are commonly used in x-ray telescopes. ...

Gubarev, M.V.

451

Neutron lifetime measurements using gravitationally trapped ultracold neutrons  

SciTech Connect (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{+-}0.7{sub stat}{+-}0.3{sub sys} s, is the most accurate experimental measurement to date.

Serebrov, A. P.; Varlamov, V. E.; Kharitonov, A. G.; Fomin, A. K.; Krasnoschekova, I. A.; Lasakov, M. S.; Taldaev, R. R.; Vassiljev, A. V.; Zherebtsov, O. M. [Petersburg Nuclear Physics Institute, Russian Academy of Sciences, RU-188300 Gatchina, Leningrad District (Russian Federation); Pokotilovski, Yu. N. [Joint Institute for Nuclear Research, RU-141980 Dubna, Moscow Region (Russian Federation); Geltenbort, P. [Institut Max von Laue Paul Langevin, Boite Postal 156, F-38042 Grenoble Cedex 9 (France)

2008-09-15T23:59:59.000Z

452

Neutron Scattering Instrumentation for Biology at Spallation Neutron Sources  

Science Journals Connector (OSTI)

Conventional wisdom holds that since biological entities are large, they must be studied with cold neutrons, a domain in which reactor sources of neutrons are often supposed to be pre-eminent. ... fact, the curre...

Roger Pynn

1996-01-01T23:59:59.000Z

453

Electron-neutron scattering and transport properties of neutron stars  

E-Print Network [OSTI]

We show that electrons can couple to the neutron excitations in neutron stars and find that this can limit their contribution to the transport properties of dense matter, especially the shear viscosity. The coupling between electrons and neutrons is induced by protons in the core, and by ions in the crust. We calculate the effective electron-neutron interaction for the kinematics of relevance to the scattering of degenerate electrons at high density. We use this interaction to calculate the electron thermal conductivity, electrical conductivity, and shear viscosity in the neutron star inner crust, and in the core where we consider both normal and superfluid phases of neutron-rich matter. In some cases, particularly when protons are superconducting and neutrons are in their normal phase, we find that electron-neutron scattering can be more important than the other scattering mechanisms considered previously.

Bertoni, Bridget; Rrapaj, Ermal

2014-01-01T23:59:59.000Z

454

Resonance Neutron Capture in Nb93  

Science Journals Connector (OSTI)

Spectra from radiative capture in S- and P-wave resonances in Nb93 have been compared. Differences in these spectra are interpreted to indicate the presence of sizable two-particleone-hole components in the capturing states. S-wave intensities show no correlation with (d,p) intensities to the same final states, but P-wave intensities exhibit a significant correlation. Lack of a correlation with the initial-state reduced widths rules out an appreciable channel-capture effect in this experiment. The differences in S- and P-wave total radiation widths are discussed. Seven neutron-resonance spin assignments are made, based on the capture ?-ray spectra, and 11 new final states in Nb94 are observed and tabulated.

R. E. Chrien; K. Rimawi; J. B. Garg

1971-05-01T23:59:59.000Z

455

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

Broader source: Energy.gov (indexed) [DOE]

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,

456

Bowen blend echo-tomography of low mass X-ray binaries  

E-Print Network [OSTI]

We present simultaneous high time resolution (1-10 Hz) X-ray and optical observations of the persistent LMXBs Sco X-1 and V801 Ara(=4U 1636-536). In the case of Sco X-1 we find that the Bowen/HeII emission lags the X-ray light-curves with a light travel time of ~11-16s which is consistent with reprocessing in the donor star. We also present the detection of three correlated X-ray/optical bursts in V801 ara. Although this latter project is still in progress our preliminary results obtained by subtracting the Continuum light-curve from the Bowen/HeII data provide evidence of orbital phase dependent echoes from the companion star.

T. Muoz-Darias; I. G. Martinez-Pais; J. Casares; R. Cornelisse; V. S. Dhillon; T. R. Marsh; D. Steeghs; K. O'Brien; P. A. Charles; M. Still

2007-09-21T23:59:59.000Z

457

Why the two-pulse photon echo is not a good quantum memory protocol  

SciTech Connect (OSTI)

We consider in this paper a two-pulse photon echo sequence in the prospect of quantum light storage. We analyze the conditions where quantum storage could be realistically performed. We simply and analytically calculate the efficiency in that limit, and clarify the role of the exactly {pi}-rephasing pulse in the sequence. Our physical interpretation of the process is well supported by its experimental implementation in a Tm{sup 3+}:yttrium aluminum garnet crystal thanks to an accurate control of the rephasing pulse area. We finally address independently the fundamental limitations of the quantum fidelity. Our work allows us to point out on one side the real drawbacks of this scheme for quantum storage and on the other side its specificities which can be a source of inspiration to conceive more promising procedures with rare-earth ion doped crystals.

Ruggiero, Jerome; Le Goueet, Jean-Louis; Chaneliere, Thierry [Laboratoire Aime Cotton, CNRS-UPR 3321, Universite Paris-Sud, Bat. 505, 91405 Orsay Cedex (France); Simon, Christoph [Group of Applied Physics, University of Geneva, CH-1211 Geneva 4 (Switzerland)

2009-05-15T23:59:59.000Z

458

EChO spectra and stellar activity II. The case of dM stars  

E-Print Network [OSTI]

EChO is a dedicated mission to investigate exoplanetary atmospheres. When extracting the planetary signal, one has to take care of the variability of the hosting star, which introduces spectral distortion that can be mistaken as planetary signal. Magnetic variability is a major deal in particular for M stars. To this purpose, assuming a one spot dominant model for the stellar photosphere, we develop a mixed observational-theoretical tool to extract the spot's parameters from the observed optical spectrum. This method relies on a robust library of spectral M templates, which we derive using the observed spectra of quiet M dwarfs in the SDSS database. Our procedure allows to correct the observed spectra for photospheric activity in most of the analyzed cases, reducing the spectral distortion down to the noise levels. Ongoing refinements of the template library and the algorithm will improve the efficiency of our algorithm.

Scandariato, G

2014-01-01T23:59:59.000Z

459

Storage and Manipulation of Light Using a Raman Gradient Echo Process  

E-Print Network [OSTI]

The Gradient Echo Memory (GEM) scheme has potential to be a suitable protocol for storage and retrieval of optical quantum information. In this paper, we review the properties of the $\\Lambda$-GEM method that stores information in the ground states of three-level atomic ensembles via Raman coupling. The scheme is versatile in that it can store and re-sequence multiple pulses of light. To date, this scheme has been implemented using warm rubidium gas cells. There are different phenomena that can influence the performance of these atomic systems. We investigate the impact of atomic motion and four-wave mixing and present experiments that show how parasitic four-wave mixing can be mitigated. We also use the memory to demonstrate preservation of pulse shape and the backward retrieval of pulses.

Hosseini, M; Campbell, G T; Lam, P K; Buchler, B C

2012-01-01T23:59:59.000Z

460

Radar echo, Doppler Effect and Radar detection in the uniformly accelerated reference frame  

E-Print Network [OSTI]

The uniformly accelerated reference frame described by Hamilton, Desloge and Philpott involves the observers who perform the hyperbolic motion with constant proper acceleration gi. They start to move from different distances measured from the origin O of the inertial reference frame K(XOY), along its OX axis with zero initial velocity. Equipped with clocks and light sources they are engaged with each other in Radar echo, Doppler Effect and Radar detection experiments. They are also engaged in the same experiments with an inertial observer at rest in K(XOY) and located at its origin O. We derive formulas that account for the experiments mentioned above. We study also the landing conditions of the accelerating observers on a uniformly moving platform.

Bernhard Rothenstein; Stefan Popescu

2006-09-14T23:59:59.000Z

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.


461

The neutron identified: Sir James Chadwick  

Science Journals Connector (OSTI)

The neutron identified: Sir James Chadwick ... Uses source material to describe the discovery of the neutron by James Chadwick. ...

Alfred B. Garrett

1962-01-01T23:59:59.000Z

462

Portable Neutron Sensors for Emergency Response Operations  

SciTech Connect (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

463

ULTRASOUND PULSE-ECHO IMAGING USING THE SPLIT-STEP FOURIER PROPAGATOR  

SciTech Connect (OSTI)

Ultrasonic reflection imaging has the potential to produce higher image resolution than transmission tomography, but imaging resolution and quality still need to be further improved for early cancer detection and diagnosis. We present an ultrasound reflection image reconstruction method using the split-step Fourier propagator. It is based on recursive inward continuation of ultrasonic wavefields in the frequency-space and frequency-wavenumber domains. The inward continuation within each extrapolation interval consists of two steps. In the first step, a phase-shift term is applied to the data in the frequency-wavenumber domain for propagation in a reference medium. The second step consists of applying another phase-shift term to data in the frequency-space domain to approximately compensate for ultrasonic scattering effects of heterogeneities within the breast. We use synthetic ultrasound pulse-echo data recorded around a ring for heterogeneous, computer-generated numerical breast phantoms to study the imaging capability of the method. The phantoms are derived from an experimental breast phantom and a sound-speed tomography image of an in-vivo ultrasound breast data collected usi ng a ring array. The heterogeneous sound-speed models used for pulse-echo imaging are obtained using a computationally efficient, first-arrival-time (time-of-flight) transmission tomography method. Our studies demonstrate that reflection image reconstruction using the split-step Fourier propagator with heterogeneous sound-speed models significantly improves image quality and resolution. We also numerically verify the spatial sampling criterion of wavefields for a ring transducer array.

HUANG, LIANJIE [Los Alamos National Laboratory; QUAN, YOULI [Los Alamos National Laboratory

2007-01-31T23:59:59.000Z

464

Neutron scattering above 25 MeV with monoenergetic neutrons  

Science Journals Connector (OSTI)

Technical problems encountered in measuring elastic and inelastic neutron scattering at kinetic energies well above 25 MeV are considered by extrapolating from experience with lower energy neutrons. It is concluded that all of the techniques required for a high?quality systematic study of neutron scatteringwith the notable exception of a suitable accelerator facilityare at hand.

Roger W. Finlay

1985-01-01T23:59:59.000Z

465

Coalescing Neutron Stars -- a Step Towards Physical Models. I. Hydrodynamic Evolution and Gravitational-Wave Emission  

E-Print Network [OSTI]

We investigate the dynamics and evolution of coalescing neutron stars. Although the code (Piecewise Parabolic Method) is purely Newtonian, we do include the emission of gravitational waves and their backreaction on the hydrodynamic flow. The properties of neutron star matter are described by the physical equation of state of Lattimer \\& Swesty (1991). Energy loss by all types of neutrinos and changes of the electron fraction due to the emission of electron neutrinos and antineutrinos are taken into account by an elaborate ``neutrino leakage scheme''. We simulate the coalescence of two identical, cool neutron stars with a baryonic mass of $\\approx\\!1.6\\,M_\\odot$ and a radius of $\\approx\\!15$~km and with an initial center-to-center distance of 42~km. The initial distributions of density and electron concentration are given from a model of a cold neutron star in hydrostatic equilibrium (central temperature about $8\\,{\\rm MeV}$). We investigate three cases which differ by the initial velocity distribution in the neutron stars, representing different cases of the neutron star spins relative to the direction of the orbital angular momentum vector. Within about 1~ms the neutron stars merge into a rapidly spinning ($P_{\\rm spin}\\approx 1$~ms), high-density body ($\\rho\\approx 10^{14}$~g/cm$^3$) with a surrounding thick disk of material with densities $\\rho\\approx 10^{10}-10^{12}$~g/cm$^3$ and orbital velocities of~0.3--0.5~c. In this work we evaluate the models in detail with respect to the gravitational wave emission using the quadrupole approximation. In a forthcoming paper we will concentrate on the neutrino emission and implications for gamma-ray bursters. A maximum luminosity in excess of $10^{55}$~erg/s is reached for about 1~ms.

M. Ruffert; H. -Th. Janka; G. Schaefer

1995-09-01T23:59:59.000Z

466

Sandia Neutron Detector Is Based on Polyacetylene  

Science Journals Connector (OSTI)

Sandia Neutron Detector Is Based on Polyacetylene ... It also might form the basis of an electrically readable dosimeter that records neutron flux (measured as neutrons per square centimeter) as well as a detector that could provide a cross-sectional image of neutron flux with high spatial resolution. ... Hence, most neutron detectors use a converter material that converts the neutrons to charged particles. ...

RUDY BAUM

1987-02-09T23:59:59.000Z

467

Neutron Science | More Science | ORNL  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

ORNL's long history of neutron science began in the 1940s with the pioneering neutron scattering studies of Ernest Wollan and Clifford Shull. Shull was co-recipient of...

468

High flux compact neutron generators  

E-Print Network [OSTI]

High Flux Compact Neutron Generators J. Reijonen ,1 , T-Compact high flux neutron generators are developed at thevoltage feed through of the generator is shown in Fig. 4.

Reijonen, J.; Lou, T.-P.; Tolmachoff, B.; Leung, K.-N.; Verbeke, J.; Vujic, J.

2001-01-01T23:59:59.000Z

469

Spin squeezing in the Ising model  

Science Journals Connector (OSTI)

We analyze the collective spin noise in interacting spin systems. General expressions are derived for the short-time behavior of spin systems with general spin-spin interactions, and we suggest optimum experimental conditions for the detection of spin squeezing. For Ising models with site-dependent nearest-neighbor interactions, general expressions are presented for the spin squeezing parameter for all times. The reduction of collective spin noise can be used to verify the entangling powers of quantum computer architectures based on interacting spins.

Xiaoguang Wang; Anders Sndberg Srensen; Klaus Mlmer

2001-10-12T23:59:59.000Z

470

Neutron Scattering Conference Archive  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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/

471

Industry - ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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,"

472

Contacts | ORNL Neutron Sciences  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (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

473

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, Roger B. (Lafayette, CO); Tyree, William H. (Boulder, CO)

1984-12-18T23:59:59.000Z

474

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

475

Cooling of neutron stars  

Science Journals Connector (OSTI)

On the basis of current physical understanding, it is impossible to predict with confidence the interior constitution of neutron stars. Cooling of neutron stars provides a possible way of discriminating among possible states of matter within them. In the standard picture of cooling by neutrino emission developed over the past quarter of a century, neutron stars are expected to cool relatively slowly if their cores are made up of nucleons, and to cool faster if matter is in an exotic state, such as a pion condensate, a kaon condensate, or quark matter. This view has recently been called into question by the discovery of a number of other processes that could lead to copious neutrino emission and rapid cooling.

C. J. Pethick

1992-10-01T23:59:59.000Z

476

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

477

Corrosion resistant neutron absorbing coatings  

DOE Patents [OSTI]

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

478

Corrosion resistant neutron absorbing coatings  

DOE Patents [OSTI]

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; Farmer, Joseph C; Lee, Chuck K; Walker, Jeffrey; Russell, Paige; Kirkwood, Jon; Yang, Nancy; Champagne, Victor

2013-11-12T23:59:59.000Z

479

Passive Neutron Detection at Borders  

SciTech Connect (OSTI)

Radiation portal monitor systems have been deployed to screen for illicit trafficking of radioactive materials at international border crossings. This report reviews some of the neutron detection requirements and capabilities of passive detection systems used for such applications. Simulations show the effects of cargo materials on neutron spectra, different detector geometries, using a large-array of neutron detectors, and the effects of backgrounds including ship effect neutrons.

Kouzes, Richard T.; Siciliano, Edward R.; Ely, James H.; Keller, Paul E.; McConn, Ronald J.

2008-03-01T23:59:59.000Z

480

Quantization of Spin-2 Fields  

Science Journals Connector (OSTI)

A massive spin-2 field has been quantized using Schwinger's action principle. Lorentz invariance and physical positive-definiteness requirements have been verified.

Shau-jin Chang

1966-08-26T23:59:59.000Z

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.


481

Inelastic Neutron Scattering Instrumentation  

Science Journals Connector (OSTI)

Abstract Inelastic neutron scattering spectroscopy spans an enormous energy range, which is equivalent to a wide range of timescales. It is convenient to divide the whole energy range into three sectors, while recognising that there is significant overlap between them. In the lowest energy range, 10meV the applications are principally quasielastic scattering and tunneling spectroscopy. The second range, 01000meV covers the regions of vibrational spectroscopy and magnetic excitations. The highest range above 1000meV is the province of neutron Compton scattering. The instrumentation used in each of these energy regimes is described.

S.F. Parker

2014-01-01T23:59:59.000Z

482

Neutron Bombardment of Counting Diamonds  

Science Journals Connector (OSTI)

21 February 1956 research-article Neutron Bombardment of Counting Diamonds A. H...Examination was also made of the effect of neutron bombardment on pulse-height distribution...additional charge traps produced by the neutrons. The layered crystal texture disclosed...

1956-01-01T23:59:59.000Z

483

NOTES ON NEUTRON DEPTH PROFILING  

E-Print Network [OSTI]

NOTES ON NEUTRON DEPTH PROFILING by J.K. Shultis Department of Mechanical and Nuclear Engineering College of Engineering Kansas State University Manhattan, Kansas 66506 Dec. 2003 #12;Notes on Neutron Depth Profiling J. Kenneth Shultis December 2003 1 Introduction The purpose of neutron depth profiling

Shultis, J. Kenneth

484

Neutron - Mirror Neutron Oscillations: How Fast Might They Be?  

E-Print Network [OSTI]

We discuss the phenomenological implications of the neutron (n) oscillation into the mirror neutron (n'), a hypothetical particle exactly degenerate in mass with the neutron but sterile to normal matter. We show that the present experimental data allow a maximal n-n' oscillation in vacuum with a characteristic time $\\tau$ much shorter than the neutron lifetime, in fact as small as 1 sec. This phenomenon may manifest in neutron disappearance and regeneration experiments perfectly accessible to present experimental capabilities and may also have interesting astrophysical consequences, in particular for the propagation of ultra high energy cosmic rays.

Zurab Berezhiani; Luis Bento

2005-07-03T23:59:59.000Z

485

Scission neutron emission and prompt fission neutron spectrum  

E-Print Network [OSTI]

The mass, energy and angular integrated spectra of prompt fission neutrons for sup 2 sup 3 sup 5 U induced fission in the energy range from thermal to 5 MeV were analyzed. It allows assume that about 0.362+-0.025 neutrons per fission are emitted due to another mechanism then neutron emission from excited fragments after full acceleration. The spectrum of scission neutrons consists of two components with average energy 0.98 MeV and 2.74 MeV. The share of scission neutrons and their spectrum shape estimated in this work does not contradict to results of differential experiments analyzed in previous papers.

Kornilov, N V

2001-01-01T23:59:59.000Z

486

Determination of the Pt spin diffusion length by spin-pumping and spin Hall effect  

SciTech Connect (OSTI)

The spin diffusion length of Pt at room temperature and at 8 K is experimentally determined via spin pumping and spin Hall effect in permalloy/Pt bilayers. Voltages generated during excitation of ferromagnetic resonance from the inverse spin Hall effect and anisotropic magnetoresistance effect were investigated with a broadband approach. Varying the Pt layer thickness gives rise to an evolution of the voltage line shape due to the superposition of the above two effects. By studying the ratio of the two voltage components with the Pt layer thickness, the spin diffusion length of Pt can be directly extracted. We obtain a spin diffusion length of ?1.2 nm at room temperature and ?1.6 nm at 8 K.

Zhang, Wei; Pearson, John E.; Hoffmann, Axel [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)] [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Vlaminck, Vincent [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States) [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Colegio de Ciencias e Ingenera, Universidad San Fransciso de Quito, Quito (Ecuador); Divan, Ralu [Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States)] [Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States); Bader, Samuel D. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States) [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Center for Nanoscale Materials, Argonne National Laboratory, Illinois 60439 (United States)

2013-12-09T23:59:59.000Z

487

Mesoscopic Spin Magnetism  

Science Journals Connector (OSTI)

We investigate the spin magnetism of mesoscopic metallic grains. In the average response of an ensemble of grains there are corrections to macroscopic behavior due to both spectral fluctuations and electron-electron interactions. These corrections are a nonlinear function of the magnetic field. Their temperature dependence is calculated numerically and analytically. An experiment is proposed to measure the unknown interaction coupling constant in the Cooper channel. For a single sample the magnetization is found to fluctuate reproducibly about the mean. These fluctuations directly probe the energy level statistics.