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1

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

2

Revealing cyclic hardening mechanism of a TRIP steel by real-time in situ neutron diffraction  

SciTech Connect (OSTI)

Real-time in situ neutron diffraction was performed on a transformation-induced plasticity (TRIP) steel under cyclic loading at room temperature. By Rietveld refinement and single peak analysis, the volume fraction and average stress estimates as well as dislocation density of individual phases (austenite and martensite phase) were derived. The results reveal that the volume fraction of martensite phase, instead of individual phase strengthening, should be accounted for the remarkable secondary cyclic hardening.

Yu, Dunji [ORNL; An, Ke [ORNL; Chen, Yan [ORNL; Chen, Xu [Tianjin UNiversity, China

2014-01-01T23:59:59.000Z

3

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

4

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.

5

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

6

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

7

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.

8

Neutron diffraction study of decaborane  

Science Journals Connector (OSTI)

Neutron diffraction study of decaborane ... The Molecular Structure of (PSH+)(nido-7,8-C2B9H12-) Determined by Neutron Diffraction (PS = Proton Sponge, 1,8-Bis(dimethylamino)naphthalene) ... The Molecular Structure of (PSH+)(nido-7,8-C2B9H12-) Determined by Neutron Diffraction (PS = Proton Sponge, 1,8-Bis(dimethylamino)naphthalene) ...

Armin Tippe; Walter C. Hamilton

1969-03-01T23:59:59.000Z

9

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 Pendellösung 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 Pendellösung 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

10

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

11

Residual Stresses in Weldments by Neutron Diffraction  

E-Print Network [OSTI]

Residual Stresses in Weldments by Neutron Diffraction Shanmukha Rao M, Jon James, Shirley Northover :- The neutron diffraction is determined from Bragg's law. When neutron propagate through crystal sample, Coherent, Incoherent and Absorption Scattering phenomena take place Weld MaterialsPlate materials Stress

Bandara, Arosha

12

Neutron Diffraction of Ice in Hydrogels  

Science Journals Connector (OSTI)

Neutron Diffraction of Ice in Hydrogels ... (14, 15) Neutrons are also especially suited for studying D2O water in hydrogels because hydrogen atoms (H) on the polymer chains are not detectable. ...

Yurina Sekine; Tomoko Ikeda-Fukazawa; Mamoru Aizawa; Riki Kobayashi; Songxue Chi; Jaime A. Fernandez-Baca; Hiroki Yamauchi; Hiroshi Fukazawa

2014-08-26T23:59:59.000Z

13

Characterization of Li-ion Batteries using Neutron Diffraction...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Li-ion Batteries using Neutron Diffraction and Infrared Imaging Techniques Characterization of Li-ion Batteries using Neutron Diffraction and Infrared Imaging Techniques 2011 DOE...

14

Christmas burst reveals neutron star collision  

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

Christmas burst reveals neutron star collision Christmas burst reveals neutron star collision Called the Christmas Burst, GRB 101225A was freakishly lengthy and it produced...

15

Magnetic Structure Determination from Neutron Diffraction Data  

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

logo logo Magnetic Structure Determination from Neutron Diffraction Data September 17 - 20, 2012 logo Oak Ridge National Laboratory - Oak Ridge, Tennessee, USA About the Workshop Program Lecture Notes Useful Links Organizers Travel & Lodging Wireless Networking Photos filler About the Workshop molecule The Magnetic Structure Determination Workshop 2012 concluded on September 20. The aim of this workshop was to enhance the community studying magnetism in materials by learning from experts the essential theoretical foundations to magnetic representation analysis and work through real examples to gain experience in solving and refining magnetic structures from neutron powder and single crystal diffraction data. Invited speakers: Juan Rodríguez-Carvajal (ILL, Grenoble)

16

DNA hydration studied by neutron fiber diffraction  

SciTech Connect (OSTI)

The development of neutron high angle fiber diffraction to investigate the location of water around the deoxyribonucleic acid (DNA) double-helix is described. The power of the technique is illustrated by its application to the D and A conformations of DNA using the single crystal diffractometer, D19, at the Institute Laue-Langevin, Grenoble and the time of flight diffractometer, SXD, at the Rutherford Appleton ISIS Spallation Neutron Source. These studies show the existence of bound water closely associated with the DNA. The patterns of hydration in these two DNA conformations are quite distinct and are compared to those observed in X-ray single crystal studies of two-stranded oligodeoxynucleotides. Information on the location of water around the DNA double-helix from the neutron fiber diffraction studies is combined with that on the location of alkali metal cations from complementary X-ray high angle fiber diffraction studies at the Daresbury Laboratory SRS using synchrotron radiation. These analyses emphasize the importance of viewing DNA, water and ions as a single system with specific interactions between the three components and provide a basis for understanding the effect of changes in the concentration of water and ions in inducing conformations] transitions in the DNA double-helix.

Fuller, W.; Forsyth, V.T.; Mahendrasingam, A.; Langan, P.; Pigram, W.J. [Keele Univ. (United Kingdom)] [and others

1994-12-31T23:59:59.000Z

17

LANSCE | Lujan Center | Highlights | In situ neutron diffraction study of  

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

In situ neutron diffraction study of CO clathrate hydrate In situ neutron diffraction study of CO clathrate hydrate The structure of a CO clathrate hydrate has been studied for the first time using high-P low-T neutron diffraction. Clathrate Rietveld analysis shows that lattice parameter a (SII cubic clathrate structure) increases with increasing temperature. CO molecules are positionally disordered and off-centered in both large and small cages. Each large cage is occupied by two CO molecules while each small cage is occupied by one CO. A representative neutron diffraction pattern of SII CO clathrate hydrate. Variation of lattice parameter a of CO SII clathrate hydrate as a function of temperature. A representative neutron diffraction pattern of SII CO clathrate hydrate. Variation of lattice parameter a of CO SII clathrate hydrate as a function of temperature.

18

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

19

RisR1440(EN) Neutron diffraction stud-  

E-Print Network [OSTI]

. C. Canfield, Neutron scattering studies of the flux line lattice and magnetic ordering in TmNi2B2CRisø­R­1440(EN) Neutron diffraction stud- ies of magnetic ordering in superconducting ErNi2B2C Faculty of Science, University of Copenhagen January 2004 #12;Abstract This thesis describes neutron

20

High-temperature neutron diffraction study of deuterated brucite  

Science Journals Connector (OSTI)

To study the structural behavior of brucite at high temperature, we conducted in situ neutron diffraction experiments of a deuterated brucite powder sample, Mg(OD)2, in the temperature range 313–583 K. The sample...

Hongwu Xu; Yusheng Zhao; Donald D. Hickmott…

2013-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

RECENT CRYSTAL STRUCTURE DETERMINATIONS BY NEUTRON DIFFRACTION AT OAK RIDGE  

E-Print Network [OSTI]

469. RECENT CRYSTAL STRUCTURE DETERMINATIONS BY NEUTRON DIFFRACTION AT OAK RIDGE By GEORGE M. BROWN and HENRI A. LEVY, Chemistry Division Oak Ridge National Laboratory (1), Oak Ridge, Tennessee, U. S. A ont été relevées grace au diffractomètre à neutrons d'Oak Ridge position- nant automatiquement les

Paris-Sud XI, Université de

22

Supplementary Figure 1| Neutron diffraction data at 86 % relative humidity. a) Schematic representation of neutron diffraction geometry for -2 scans. Diffraction data are obtained  

E-Print Network [OSTI]

distributions of lipid and protein under varying levels of hydration. Predicted neutron scattering profiles as number density profiles weighted by the neutron scattering lengths of individual atoms, then symmetrizedSupplementary Figure 1| Neutron diffraction data at 86 % relative humidity. a) Schematic

White, Stephen

23

Christmas burst reveals neutron star collision  

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

Christmas burst reveals neutron star collision Christmas burst reveals neutron star collision Christmas burst reveals neutron star collision Called the Christmas Burst, GRB 101225A was freakishly lengthy and it produced radiation at unusually varying wavelengths. December 1, 2011 Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma physics and new materials. Los Alamos National Laboratory sits on top of a once-remote mesa in northern New Mexico with the Jemez mountains as a backdrop to research and innovation covering multi-disciplines from bioscience, sustainable energy sources, to plasma physics and new materials. Contact

24

Magnetic Structure Analysis from Neutron Powder Diffraction Data Using GSAS  

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

Magnetic Structure Analysis from Neutron Powder Diffraction Data Using GSAS Magnetic Structure Analysis from Neutron Powder Diffraction Data Using GSAS This set of web pages provides reference information from the Magnetic Structure Analysis from Neutron Powder Diffraction Data Using GSAS workshop presented at the 2006 American Conference on Neutron Scattering held in St. Charles, IL, June 18-22, 2006. Workshop Schedule: 9:00-9:05 am: Introduction (B.H. Toby) 9:05-9:50 am: History, Color symmetry & Shubnikov space groups (B. Chakoumous) Lecture notes: History and Color symmetry & Shubnikov space groups 9:50-10:20 am: Magnetic extinctions classes & common magnetic structure types (R.B. Von Dreele) Lecture Notes Break 10:50-11:45 am: Overview of representational analysis & FullProf implementation (L.C. Chapon) Lecture Notes and Accompanying files

25

Sub-Surface Residual Stress Measurements by Means of Neutron Diffraction: Aluminum, Steel, and Depleted Uranium  

Science Journals Connector (OSTI)

Neutron diffraction closely parallels x-ray diffraction in methodology and analytical formalism. However, in the normal diffraction range (? ~ 1 Å) neutrons are nondestructive and are generally about a thousand t...

H. J. Prask; C. S. Choi

1986-01-01T23:59:59.000Z

26

Oxides: neutron and synchrotron X-ray diffraction studies  

Science Journals Connector (OSTI)

......cells. Their thermal stability and high proton conductivity are particu- 15000 15500 16000 16500 17000 Time-of-flight, usec Fig. 6 Neutron diffraction pattern of the high temperature protonic conductor Ba3Ca! uNb].82O9-5 with and without D2O......

Izabela M. Sosnowska; Makoto Shiojiri

1999-01-01T23:59:59.000Z

27

Neutron diffraction study of the contribution of grain contacts to nonlinear stress-strain behavior  

E-Print Network [OSTI]

Neutron diffraction study of the contribution of grain contacts to nonlinear stress-strain behavior performed simultaneous neutron diffraction and quasi-static loading experiments on a selection of rocks to experimentally isolate the response of these contact regions. Neutron diffraction measures strain in the lattice

28

NEUTRON DIFFRACTION ANALYSIS OF CYTOCHROME b5 RECONSTITUTED IN DEUTERATED LIPID MULTILAYERS  

E-Print Network [OSTI]

NEUTRON DIFFRACTION ANALYSIS OF CYTOCHROME b5 RECONSTITUTED IN DEUTERATED LIPID MULTILAYERS E. P centrosymmetric pairs of asymmetric lipid-protein bilayers. Lamellar neutron diffraction data were collected. A neutron diffraction analysis ofcytochrome b5, incorporated into ordered lipid multilayers, promised

29

Structure of K-doped polyacetylene and its variations with annealing, studied by neutron diffraction  

E-Print Network [OSTI]

complementary information to X-ray diffraction can be obtained with neutrons. In addition, neutron scatteringL-379 Structure of K-doped polyacetylene and its variations with annealing, studied by neutron~u le 9 janvier 1985, accepte le 21 fevrier 1985) Résumé. 2014 On a étudié par diffraction de neutrons

Boyer, Edmond

30

Structural studies of magnesium nitride fluorides by powder neutron diffraction  

SciTech Connect (OSTI)

Samples of ternary nitride fluorides, Mg{sub 3}NF{sub 3} and Mg{sub 2}NF have been prepared by solid state reaction of Mg{sub 3}N{sub 2} and MgF{sub 2} at 1323-1423 K and investigated by powder X-ray and powder neutron diffraction techniques. Mg{sub 3}NF{sub 3} is cubic (space group: Pm3m) and has a structure related to rock-salt MgO, but with one cation site vacant. Mg{sub 2}NF is tetragonal (space group: I4{sub 1}/amd) and has an anti-LiFeO{sub 2} related structure. Both compounds are essentially ionic and form structures in which nitride and fluoride anions are crystallographically ordered. The nitride fluorides show temperature independent paramagnetic behaviour between 5 and 300 K. - Graphical abstract: Definitive structures of the ternary magnesium nitride fluorides Mg{sub 3}NF{sub 3} and the lower temperature polymorph of Mg{sub 2}NF have been determined from powder neutron diffraction data. The nitride halides are essentially ionic and exhibit weak temperature independent paramagnetic behaviour. Highlights: Black-Right-Pointing-Pointer Definitive structures of Mg{sub 3}NF{sub 3} and Mg{sub 2}NF were determined by neutron diffraction. Black-Right-Pointing-Pointer Nitride and fluoride anions are crystallographically ordered in both structures. Black-Right-Pointing-Pointer Both compounds exhibit weak, temperature independent paramagnetic behaviour. Black-Right-Pointing-Pointer The compounds are essentially ionic with ionicity increasing with F{sup -} content.

Brogan, Michael A. [School of Chemistry, University of Nottingham, Nottingham NG7 2RD (United Kingdom); Hughes, Robert W. [WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Smith, Ronald I. [ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX (United Kingdom); Gregory, Duncan H., E-mail: Duncan.Gregory@glasgow.ac.uk [WestCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ (United Kingdom)

2012-01-15T23:59:59.000Z

31

Attenuation corrections for X-ray and neutron fibre diffraction studies  

Science Journals Connector (OSTI)

The form of the transmission factor for sample geometries encountered in X-ray and neutron fibre diffraction studies is considered.

Langan, P.

1995-02-01T23:59:59.000Z

32

Neutron diffraction measurements of residual stresses in welds fabricated from highly anisotropic materials  

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

neutron diffraction to neutron diffraction to engineering problems T.M. Holden Northern Stress Technologies Deep River, Ontario, Canada Oak Ridge National Laboratory, 13 nd June 2011 Reference material * "Introduction to the characterization of residual stress by neutron diffraction". M.T. Hutchings, P.J. Withers, T.M. Holden and T. Lorentzen, (Taylor and Francis: Boca Raton) 2005 * "Introduction to diffraction in Materials Science and Engineering", A.D. Krawitz (John Wiley and Sons ,Inc.: New York) 2001 * "Non-destructive testing-Standard Test Method for

33

RECENT MAGNETIC STRUCTURE STUDIES BY NEUTRON DIFFRACTION(1) By C. G. SHULL,  

E-Print Network [OSTI]

classification by neutron scattering include the determination of the magnitude and quality of an atom of this moment as represented in the form factor for neutron scattering. Within the second classification169 RECENT MAGNETIC STRUCTURE STUDIES BY NEUTRON DIFFRACTION(1) By C. G. SHULL, Massachusetts

Boyer, Edmond

34

Neutron and X-ray diffraction and empirical potential structure refinement modelling of magnesium stabilised amorphous calcium  

E-Print Network [OSTI]

Neutron and X-ray diffraction and empirical potential structure refinement modelling of magnesium online xxxx Keywords: Amorphous calcium carbonate; EPSR modelling; Neutron diffraction; X-ray diffraction Amorphous calcium carbonate (ACC) plays a key role in biomineralisation processes in sea organisms. Neutron

Benning, Liane G.

35

Neutron scattering reveals extremely slow cell water in a Dead Sea organism  

Science Journals Connector (OSTI)

Neutron scattering reveals extremely slow cell water...from the Dead Sea, was studied by neutron scattering. The water in centrifuged cell pellets...marismortui cells by measuring neutron scattering in deuterium-labeled cells. Neutron...

Moeava Tehei; Bruno Franzetti; Kathleen Wood; Frank Gabel; Elisa Fabiani; Marion Jasnin; Michaela Zamponi; Dieter Oesterhelt; Giuseppe Zaccai; Margaret Ginzburg; Ben-Zion Ginzburg

2007-01-01T23:59:59.000Z

36

Neutron diffraction studies and magnetism in Ti doped SrFeO{sub 3??} systems  

SciTech Connect (OSTI)

The magnetic ground state of single phase tetragonal crystal structure with I4/mmm space group SrFe{sub 1?x}Ti{sub x}O{sub 3??} (x?=?0.2 and 0.3) is investigated from 2?K to 300?K. Strong irreversibility is observed in zero-field-cooled (ZFC) and field-cooled DC magnetization curves. Arrott plots show the absence of spontaneous magnetization (M{sub S}) down to 2?K, ruling out the possibility of long range ferromagnetic order. Neutron diffraction measurements carried out at H?=?0, 7?T (field cooled) at several temperatures above and below the T* (temperature at which M{sub ZFC}(T) is maximum) do not show any additional peaks and also no difference in intensity rules out, both the long range antiferromagnetic and ferromagnetic orders. Hence, the combined study of dc magnetization and neutron diffraction results reveals cluster spin glass behavior in SrFe{sub 1?x}Ti{sub x}O{sub 3??} (x?=?0.2 and 0.3)

Sendil Kumar, A.; Srinath, S., E-mail: srinath@uohyd.ac.in [School of Physics, University of Hyderabad, Hyderabad 500 046 (India); Babu, P. D. [UGC-DAE Consortium for Scientific Research, R-5 Shed, B.A.R.C, Mumbai 400 085 (India)

2014-03-14T23:59:59.000Z

37

High-pressure neutron diffraction study on H–D isotope effects in brucite  

Science Journals Connector (OSTI)

A neutron powder diffraction study of hydrogenated and deuterated brucite was conducted at ambient temperature and at...a axis, parallel to the sheets of Mg–O octahedra, decrease only slightly with pressure with ...

Juske Horita; António M. dos Santos…

2010-12-01T23:59:59.000Z

38

Collecting and Processing Neutron Fibre Diffraction Data from a Single-Crystal Diffractometer  

Science Journals Connector (OSTI)

An optimum strategy for collecting fibre diffraction data from a neutron single-crystal diffractometer is proposed. Methods for processing data collected using this strategy are described and illustrated by studies on cellulose.

Langan, P.

1996-08-01T23:59:59.000Z

39

Boron-10 Prompt Gamma Analysis Using a Diffracted Neutron Beam  

Science Journals Connector (OSTI)

A prompt gamma neutron activation analysis (PGNAA) facility has been built at the 5 MW MITR-II Research Reactor to support our ongoing boron neutron capture therapy (NCT) program. This facility is used to dete...

R. Rogus; O. K. Harling; I. Olmez…

1992-01-01T23:59:59.000Z

40

Complex magnetic ordering in CeFe1.76 studied by neutron diffraction  

SciTech Connect (OSTI)

Neutron diffraction measurements on a single crystal of CeGe1.76 reveal a complex series of magnetic transitions at low temperature. At TN?7 K, there is a transition from a paramagnetic state at higher temperature to an incommensurate magnetic structure characterized by a magnetic propagation vector (0 0 ?) with ??14 and the magnetic moment along the a axis of the orthorhombic unit cell. Below TLI?5 K, the magnetic structure locks in to a commensurate structure with ?=14 and the magnetic moment remains along the a axis. Below T??4 K, we find additional half-integer and integer indexed magnetic Bragg peaks consistent with a second commensurately ordered antiferromagnetic state.

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

2014-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

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

42

Neutron Laue diffraction studies of coenzyme cob(II)alamin  

Science Journals Connector (OSTI)

A novel single-crystal neutron diffractometer utilizing a polychromatic neutron beam reduces data-collection times by about one order of magnitude. It is specifically suited for applications involving crystals of biological macromolecules. It was used to determine the arrangement of solvent molecules in the crystal structure of coenzyme B12r.

Langan, P.

1999-01-01T23:59:59.000Z

43

Magnetic and crystal structures of Sr2IrO4: A neutron diffraction study  

Science Journals Connector (OSTI)

We report a single-crystal neutron diffraction study of the layered Sr2IrO4. This work unambiguously determines the magnetic structure of the system and reveals that the spin orientation rigidly tracks the staggered rotation of the IrO6 octahedra in Sr2IrO4. The long-range antiferromagnetic order has a canted spin configuration with an ordered moment of 0.208(3) ?B/Ir site within the basal plane; a detailed examination of the spin canting yields 0.202(3) and 0.049(2) ?B/site for the a axis and the b axis, respectively. It is intriguing that forbidden nuclear reflections of space group I41/acd are also observed in a wide temperature range from 4 K to 600 K, which suggests a reduced crystal structure symmetry. This neutron-scattering work provides a direct, well-refined experimental characterization of the magnetic and crystal structures that are crucial to the understanding of the unconventional magnetism exhibited in this unusual magnetic insulator.

Feng Ye, Songxue Chi, Bryan C. Chakoumakos, Jaime A. Fernandez-Baca, Tongfei Qi, and G. Cao

2013-04-22T23:59:59.000Z

44

Polymorphism in Photoluminescent KNdW2O8: Synthesis, Neutron Diffraction, and Raman Study  

SciTech Connect (OSTI)

Polymorphs of KNdW2O8 ( -KNdW2O8 and -KNdW2O8) phosphors were synthesized by an efficient solution combustion technique for the first time. The crystal structure of the polymorphs analyzed from Rietveld refinement of neutron diffraction data confirms that -KNdW2O8 crystallizes in the tetragonal system (space group I4 ), and -KNdW2O8 crystallizes in the monoclinic system (space group C2/m). The local structure of both polymorphs was elucidated using combined neutron pair distribution function (PDF) and Raman scattering techniques. Photoluminescence measurements of the polymorphs showed broadened emission line width and increased intensity for -KNdW2O8 in the visible region compared to -KNdW2O8. This phenomenon is attributed to the increased distortion in the coordination environment of the luminescing Nd3+ ion. Combined PDF, Rietveld, and Raman measurements reveal distortions of the WO6 octahedra and NdO8 polyhedra in -KNdW2O8. This crystal structure photoluminescence study suggests that this class of tungstates can be exploited for visible light emitting devices by tuning the crystal symmetry.

S. M. Bhat, Swetha [Materials Science Division, Poornaprajna Institute of Scientific Research, Bidalur Near Devanahalli,; Swain, Diptikanta [CPMU, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru, Karnataka, India] [CPMU, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru, Karnataka, India; Feygenson, Mikhail [ORNL] [ORNL; Neuefeind, Joerg C [ORNL] [ORNL; Sundaram, Nalini [Materials Science Division, Poornaprajna Institute of Scientific Research, Bidalur Near Devanahalli,] [Materials Science Division, Poornaprajna Institute of Scientific Research, Bidalur Near Devanahalli,

2014-01-01T23:59:59.000Z

45

A six-axis robotic sample changer for high-throughput neutron powder diffraction and texture measurements  

Science Journals Connector (OSTI)

A new six-axis robotic sample changer for neutron powder diffraction experiments, including texture measurements, has enabled a novel set of experiments to be performed at the High-Pressure Preferred Orientation diffractometer at the Lujan Neutron Scattering Center.

Losko, A.S.

2014-11-18T23:59:59.000Z

46

A preliminary time-of-flight neutron diffraction study on amicyanin from paracoccus denitrificans.  

SciTech Connect (OSTI)

Crystals of the blue copper protein amicyanin suitable for neutron diffraction were grown by the sitting-drop method, followed by repeated macroseeding using solutions prepared with D{sub 2}O. Although the crystal sizes were the same, crystals grown using solutions made up in H{sub 2}O in the initial stages of macroseeding and solutions with D{sub 2}O in later stages did not diffract neutrons well. However, when the protein was initially exchanged with buffered D{sub 2}O and then crystallized and also macroseeded using solutions made up in D{sub 2}O throughout, the crystals diffracted neutrons to high resolution. One of those crystals was used to collect a data set to a resolution of 1.9 {angstrom}.

Sukumar, N.; Langan, P.; Mathews, F. S.; Jones, L. H.; Thiyagarajan, P.; Schoenborn, B. P.; Davidson, V. L.; ASO; IPNS

2005-05-01T23:59:59.000Z

47

in-situ chemistry mapping of hydrogen storage materials by neutron diffraction  

SciTech Connect (OSTI)

Neutron diffraction was used to nondestructively study the microstructures for two hydrogen storage media systems. In the first case, sodium alanate based hydrogen storage is a vehicle-scale candidate system developed by Sandia/GM. Neutron scattering was used to determine the distribution of phases in the storage media at different hydrogen loading levels, to help understand the absorption/desorption of hydrogen in large-scale systems. This study also included a 3D neutron tomographic study of the microstructure. In the second case, tin-doped lanthanum nickel alloys have been studied at JPL for space-based applications, for which the gradual degradation of the material due to segregation and disproportionation of phases is a known problem. A regenerative process developed to restore the storage properties of these alloys was studied, using in-situ neutron diffraction to relate the microstructure to the thermodynamic simulations.

Payzant, E Andrew [ORNL] [ORNL; Bowman Jr, Robert C [ORNL] [ORNL; Johnson, Terry A [Sandia National Laboratories (SNL)] [Sandia National Laboratories (SNL); Jorgensen, Scott W [GM R& D and Planning, Warren, Michigan] [GM R& D and Planning, Warren, Michigan

2013-01-01T23:59:59.000Z

48

Combined X-ray and neutron fibre diffraction studies of biological and synthetic polymers.  

SciTech Connect (OSTI)

The fibrous state is a natural one for polymer molecules which tend to assume regular helical conformations rather than the globular structures characteristic of many proteins. Fibre diffraction therefore has broad application to the study of a wide range of biological and synthetic polymers. The purpose of this paper is to illustrate the general scope of the method and in particular to demonstrate the impact of a combined approach involving both X-ray and neutron diffraction methods. While the flux of modern X-ray synchrotron radiation sources allows high quality datasets to be recorded with good resolution within a very short space of time, neutron studies can provide unique information through the ability to locate hydrogen or deuterium atoms that are often difficult or impossible to locate using X-ray methods. Furthermore, neutron fibre diffraction methods can, through the ability to selectively label specific parts of a structure, be used to highlight novel aspects of polymer structure that can not be studied using X-rays. Two examples are given. The first describes X-ray and neutron diffraction studies of conformational transitions in DNA. The second describes structural studies of the synthetic high-performance polymer poly(p-phenylene terephthalamide) (PPTA), known commercially as Kevlar{reg_sign} or Twaron{reg_sign}.

Parrot, I. M. [Institut Laue-Langevin (ILL); Urban, Volker S [ORNL; Gardner, K. H. [DuPont Experimental Station; Forsyth, V. T. [Institut Laue Langevin and Keele University

2005-04-01T23:59:59.000Z

49

Processing of Neutron Diffraction Data for Strain Measurement in Geological Materials  

SciTech Connect (OSTI)

: Conventional rock mechanics testing techniques typically involve the loading of samples and measurement of displacements or strains on the outer boundary of the specimen surface. Neutron diffraction based strain measurement techniques represent a unique and powerful tool for measuring the strain within geological materials under load. The structural variability and non-uniform crystallinity of geological materials, however, create many complexities in the intensity patterns that must be analyzed to quantify strains within the material. The attenuating and scattering properties of the pressure cell housing the sample further add difficulties to the data analysis. This paper describes the methods and processes used to process neutron scattering data for strain measurement in geological materials. It is intended to provide a primer for those in the rock mechanics community that are interested in utilizing this technique along with additional discussion of neutron diffraction experimental factors that may affect data quality.

Polsky, Yarom [ORNL] [ORNL; An, Ke [ORNL] [ORNL; Anovitz, Lawrence {Larry} M [ORNL; Bingham, Philip R [ORNL] [ORNL; Carmichael, Justin R [ORNL] [ORNL; Dessieux Jr, Luc Lucius [ORNL] [ORNL

2014-01-01T23:59:59.000Z

50

Hydrogen bonds of DsrD protein revealed by neutron crystallography  

Science Journals Connector (OSTI)

Hydrogen bonds of DNA-binding protein DsrD have been determined by neutron diffraction. In terms of proton donors and acceptors, DsrD protein shows striking differences from other proteins.

Chatake, T.

2008-04-18T23:59:59.000Z

51

Visualizing the Structural Evolution of LSM/xYSZ Composite Cathodes for SOFC by in-situ Neutron Diffraction  

SciTech Connect (OSTI)

Composite cathodes for solid oxide fuel cells, the mixtures of (La0.8Sr0.2)0.95MnO3- (LSM) and (Y2O3)x(ZrO2)1-x (xYSZ, x = 3, 6, 8 and 10), have the thermal stability unraveled at elevated temperatures by using in-situ neutron diffraction. The Rietveld refinement analysis of neutron diffraction visualizes the phase evolutions and the ion activities in the material systems. The phase transition of tetragonal YSZ at T > 900 C leads to a heterogeneous redistribution of Mn ions. The reaction of LSM and YSZ occurring at T > 1100 C was revealed as a three-stage process, yielding La2Zr2O7, SrZrO3 and MnO. The activities of Y, Mn and La ions at elevated temperatures are derived by the structural analysis, and the three-stage reaction of YSZ and LSM was found strongly correlated to ions behaviors.

Chen, Yan [ORNL] [ORNL; Yang, Ling [ORNL] [ORNL; Ren, Fei [ORNL] [ORNL; An, Ke [ORNL] [ORNL

2014-01-01T23:59:59.000Z

52

A powder neutron diffraction study of the magnetic structure of FeV{sub 2}S{sub 4}  

SciTech Connect (OSTI)

Variable-temperature powder neutron diffraction data demonstrate that FeV{sub 2}S{sub 4} undergoes a transition to a long-range magnetically ordered state at 135(7) K, in agreement with magnetic susceptibility data. High-resolution neutron diffraction data collected at 1.9 K reveal that magnetic ordering results in a doubling of the crystallographic unit-cell dimensions (I2/m a = 5.8303(2), b = 3.2761(1), c = 11.2398(4) {angstrom}, {beta} = 92.046(2){degree}) in the a and c directions and that the magnetic structure is described by a propagation vector of ({1/2}, 0, {1/2}). Cations in an ordered defect layer, 76% of which are Fe(II), possess an average ordered moment of 1.86(5) {mu}{sub B}, which is directed at an angle of 75{degree} to the layer. Cation-cation interactions reduce the average moment of cations in the MS{sub 2} unit to 0.17(4) {mu}{sub B}. The complex magnetic structure involves essentially collinear antiferromagnetic ordering between nearest-neighbor cations.

Powell, A.V.; Vaqueiro, P. [Heriot-Watt Univ., Edinburgh (United Kingdom). Dept. of Chemistry] [Heriot-Watt Univ., Edinburgh (United Kingdom). Dept. of Chemistry; Ritter, C. [Inst. Max von Laue-Paul Langevin, Grenoble (France)] [Inst. Max von Laue-Paul Langevin, Grenoble (France)

1999-05-01T23:59:59.000Z

53

Neutron diffraction studies on the Heusler alloy Ni{sub 50}Mn{sub 37}Sb{sub 13}  

SciTech Connect (OSTI)

The evolution of martensitic to austenitic transformation in Ni{sub 50}Mn{sub 37}Sb{sub 13} has been studied usingtemperature dependent neutron diffraction, thermal property, and magnetization studies. Differential scanning calorimetric studies reveal a martensitic transformation T{sub M} around 291 K. The magnetization data yield a ferromagnetic ordering temperature of 329 K in the austenitic phase and 230 K in the martensitic phase. The analysis of the powder neutron diffraction data in the temperature range of 325-12 K indicates a structural transition from a high temperature cubic L2{sub 1} type structure to an orthorhombic structure. At 270 K, both cubic and orthorhombic phases coexist. Anisotropic unit cell changes are observed at the martensitic transformation: The unit cell expands by about 1.5% along the a axis, by about 2.5% along the c axis, and compresses by about 4.28% along the b axis. Both cubic and orthorhombic phases show commensurate collinear ferromagnetic ordering with a magnetic moment of {approx}3.67 {mu}{sub B}/Mn in Mn (2a and 2f) sites.

Rama Rao, N. V.; Chelvane, J. Arout; Chandrasekaran, V. [Defence Metallurgical Research Laboratory, Hyderabad 500 058 (India); Morozkin, A. V. [Department of Chemistry, Moscow Lomonosov State University, Moscow 119992 (Russian Federation); Lamsal, J. [Department of Physics and Astronomy, University of Missouri-Columbia, Columbia, Missouri 65211 (United States); Yelon, W. B. [Materials Research Center and Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri 65409 (United States); Nirmala, R. [Department of Physics, Indian Institute of Technology Madras, Chennai 600 036 (India); Suresh, K. G. [Department of Physics, Indian Institute of Technology Bombay, Mumbai 400 076 (India); Malik, S. K. [International Institute of Physics (IIP)-UFRN, Natal, 59072-970 (Brazil)

2011-04-01T23:59:59.000Z

54

Crystal Structure and Hydrogen-Bonding System in Cellulose I? from Synchrotron X-ray and Neutron Fiber Diffraction  

Science Journals Connector (OSTI)

The crystal and molecular structure together with the hydrogen-bonding system in cellulose I? has been determined using synchrotron and neutron diffraction data recorded from oriented fibrous samples prepared by aligning cellulose microcrystals from ...?

Yoshiharu Nishiyama; Paul Langan; Henri Chanzy

2002-07-10T23:59:59.000Z

55

Structure determination of Ag-Ge-S glasses using neutron diffraction  

Science Journals Connector (OSTI)

The structure of the superionic glass system (Ag2S)x(GeS2)1-x, for three compositions x=0.3, 0.4, 0.5, has been studied using neutron diffraction, and isotopic-substitution neutron-diffraction experiments have been performed on three silver isotope-substituted (107Ag,natAg,109Ag) samples of the composition (Ag2S)0.5(GeS2)0.5. The average short-range orderings of Ge-S, Ag-S, and Ge-Ag correlations were identified in the radial distribution functions for the isotopically substituted system of (Ag2S)0.5(GeS2)0.5. From the first and second differences in the three sets of isotopic-substitution neutron-diffraction data, the other three partial correlations (Ag-Ag, Ge-Ge, and S-S), were also identified. By examining unusually broad peaks in the Ag-Ag correlation function, it was concluded that the Ag-Ag distribution was rather homogeneous. We were also able to obtain further information by combining the first and second difference analyses, resulting in a structural model of a slightly elongated GeS4 tetrahedron with the local environment of Ag+ ions being threefold coordination by nonbridging sulphur ions. The medium-range order of the host framework was found to be a chainlike structure of linked corner-sharing GeS4 tetrahedra. Substantial changes in the first and second peaks in the distinct scattering functions i(Q) were found with composition and also with isotopic substitution. It was possible to explain the trends in the changes of the heights of these peaks in the structure factor by applying the void model for the first sharp diffraction peak. © 1996 The American Physical Society.

J. H. Lee; A. P. Owens; A. Pradel; A. C. Hannon; M. Ribes; S. R. Elliott

1996-08-01T23:59:59.000Z

56

Time-of-flight neutron diffraction study of bovine [gamma]-chymotrypsin at the Protein Crystallography Station  

SciTech Connect (OSTI)

The overarching goal of this research project is to determine, for a subset of proteins, exact hydrogen positions using neutron diffraction, thereby improving H-atom placement in proteins so that they may be better used in various computational methods that are critically dependent upon said placement. In order to be considered applicable for neutron diffraction studies, the protein of choice must be amenable to ultrahigh-resolution X-ray crystallography, be able to form large crystals (1 mm{sup 3} or greater) and have a modestly sized unit cell (no dimension longer than 100 {angstrom}). As such, {gamma}-chymotrypsin is a perfect candidate for neutron diffraction. To understand and probe the role of specific active-site residues and hydrogen-bonding patterns in {gamma}-chymotrypsin, neutron diffraction studies were initiated at the Protein Crystallography Station (PCS) at Los Alamos Neutron Science Center (LANSCE). A large single crystal was subjected to H/D exchange prior to data collection. Time-of-flight neutron diffraction data were collected to 2.0 {angstrom} resolution at the PCS with 85% completeness. Here, the first time-of-flight neutron data collection from {gamma}-chymotrypsin is reported.

Lazar, Louis M.; Fisher, S. Zoe; Moulin, Aaron G.; Kovalevsky, Andrey; Novak, Walter R.P.; Langan, Paul; Petsko, Gregory A.; Ringe, Dagmar (Brandeis); (LANL)

2012-02-06T23:59:59.000Z

57

X–ray and neutron diffraction studies and MD simulation of atomic configurations in polyamorphic Y2O3-Al2O3 systems  

Science Journals Connector (OSTI)

...McMillan and David C. Clary X-ray and neutron diffraction studies and MD simulation...new results of structural studies using neutron and high-energy X-ray diffraction...pair-correlation functions obtained from X-ray and neutron scattering data. Unexpectedly large density...

2005-01-01T23:59:59.000Z

58

Conformational Changes in Sindbis Virus Induced by Decreased pH Are Revealed by Small-Angle Neutron Scattering  

Science Journals Connector (OSTI)

...Are Revealed by Small-Angle Neutron Scattering Lilin He a b Amanda Piper c...Oak Ridge, Tennessee, USA b Neutron Scattering Sciences Division, Oak Ridge...we employed small-angle neutron scattering with contrast variation to...

Lilin He; Amanda Piper; Flora Meilleur; Raquel Hernandez; William T. Heller; Dennis T. Brown

2011-12-07T23:59:59.000Z

59

A revised structure and hydrogen bonding system in cellulose II from a neutron fiber diffraction analysis  

SciTech Connect (OSTI)

The crystal and molecular structure and hydrogen bonding system in cellulose II have been revised using new neutron diffraction data extending to 1.2 {angstrom} resolution collected from two highly crystalline fiber samples of mercerized flax. Mercerization was achieved in NaOH/H{sub 2}O for one sample and in NaOD/D{sub 2}O for the other, corresponding to the labile hydroxymethyl moieties being hydrogenated and deuterated, respectively. Fourier difference maps were calculated in which neutron difference amplitudes were combined with phases calculated from two revised X-ray models of cellulose II. The revised phasing models were determined by refinement against the X-ray data set of Kolpak and Blackwell, using the LALS methodology. Both models have two antiparallel chains organized in a P2{sub 1} space group and unit cell parameters: a = 8.01 {angstrom}, b = 9.04 {angstrom}, c = 10.36 {angstrom}, and {gamma} = 117.1{degree}. One has equivalent backbone conformations for both chains but different conformations for the hydroxymethyl moieties: gt for the origin chain and tg for the center chain. The second model based on the recent crystal structures of cellotetraose, has different conformations for the two chains but nearly equivalent conformations for the hydroxymethyl moieties. On the basis of the X-ray data alone, the models could not be differentiated. From the neutron Fourier difference maps, possible labile hydrogen atom positions were identified for each model and refined using LALS. The second model is significantly different from previous proposals based on the crystal structures of cellotetraose, MD simulations of cellulose II, and any potential hydrogen-bonding network in the structure of cellulose II determined in earlier X-ray fiber diffraction studies. The exact localization of the labile hydrogen atoms involved in this bonding, together with their donor and acceptor characteristics, is presented and discussed. This study provides, for the first time, the coordinates of all of the atoms in cellulose II.

Langan, P.; Nishiyama, Y.; Chanzy, H.

1999-11-03T23:59:59.000Z

60

UNITED STATES ATOMIC ENERGY COMMISSION OAK RIDGE TENNESSEE THE DIFFRACTION OF NEUTRONS BY CRYSTALLINE POWDERS  

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

MDDC 869 MDDC 869 UNITED STATES ATOMIC ENERGY COMMISSION OAK RIDGE TENNESSEE THE DIFFRACTION OF NEUTRONS BY CRYSTALLINE POWDERS by E. 0. Wollan C. G. Shull Clinton Laboratories Published for use within the Atomic Energy Commission. Inquiries for additional -copies and any questions regarding reproduction by recipients of this document may be referred to the Documents Distribution Subsection, Publication Section, Technical Information Branch, Atomic Energy Commission, P. 0. Box E, Oak Ridge, Tennessee. Inasmuch as a declassified document may differ materially from the original classified document by reason of deletions necessary to accomplish declassification, this copy does not constitute authority for declassification of classified copies of a similar document which may bear the same title and authors.

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61

Experimental determination of residual stress by neutron diffraction in a boiling water reactor core shroud  

SciTech Connect (OSTI)

Residual strains in a 51 mm (2-inch) thick 304L stainless steel plate have been measured by neutron diffraction and interpreted in terms of residual stress. The plate, measuring (300 mm) in area, was removed from a 6m (20-ft.) diameter unirradiated boiling water reactor core shroud, and included a multiple-pass horizontal weld which joined two of the cylindrical shells which comprise the core shroud. Residual stress mapping was undertaken in the heat affected zone, concentrating on the outside half of the plate thickness. Variations in residual stresses with location appeared consistent with trends expected from finite element calculations, considering that a large fraction of the residual hoop stress was released upon removal of the plate from the core shroud cylinder.

Payzant, A.; Spooner, S.; Zhu, Xiaojing; Hubbard, C.R. [and others

1996-06-01T23:59:59.000Z

62

Neutron Diffraction Study of the Magnetic Structure of Hematite to 41 kbar  

Science Journals Connector (OSTI)

Time-of-flight neutron diffraction has been used to study the pressure dependence of the magnetic moment direction in ?-Fe2O3 to 41 kbar. The pressure dependence of the magnetic moment direction at room temperature is found to be in agreement with the pressure dependence calculated from measurements of the quadrupole splitting at high pressure by Vaughan and Drickamer, using the Mössbauer effect. It is found that the spin direction varies slowly and continuously with pressure above 14 kbar, with no well-defined Morin transition occurring at room temperature. The large pressure dependence of the Morin transition at lower pressures is well accounted for by Searle's theory based on the magnetoelastic effect. The slow variation of the spin direction at higher pressures must be accounted for by higher-order contributions to the anisotropy energy.

T. G. Worlton and D. L. Decker

1968-07-10T23:59:59.000Z

63

Neutron diffraction determination of the residual stress redistribution in cracked autofrettaged tubing  

SciTech Connect (OSTI)

Neutron diffraction has been used to measure the residual stress distributions in uncracked and fatigue cracked rings taken from a high strength, low alloy steel autofrettage tube with a bore diameter of 60mm and a wall thickness of 32mm. Stresses were determined to a precision of {plus minus} 10MPa. Three crack sixes were examines. No appreciable stress redistribution was observed until the crack was grown into a region which originally contained tensile residual hoop stress. When this occurred an increase in residual hoop tension was observed ahead of the crick tip. Qualitative agreement was achieved between the measured hoop stress distribution and values predicted using a boundary element method. 9 refs., 12 figs.

Bourke, M.A. (Los Alamos National Lab., NM (USA)); McGillivray, H.J.; Webster, G.A. (Imperial Coll. of Science, Technology and Medicine, London (UK). Dept. of Mechanical Engineering); Webster, P.J. (Salford Univ. (UK). Dept. of Civil Engineering)

1991-01-01T23:59:59.000Z

64

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

65

Static compression and H disorder in brucite, Mg(OH)2, to 11 GPa: a powder neutron diffraction study  

Science Journals Connector (OSTI)

Neutron diffraction data suitable for Rietveld refinements were collected on a powder sample of synthetic Mg(OH)2 by the Polaris time-of-flight spectrometer (ISIS spallation source, U.K.) at 10-4 7.8(3) and 10.9(...

M. Catti; G. Ferraris; S. Hull; A. Pavese

1995-04-01T23:59:59.000Z

66

CO2 Sorption to Subsingle Hydration Layer Montmorillonite Clay Studied by Excess Sorption and Neutron Diffraction Measurements  

Science Journals Connector (OSTI)

Neutron diffraction data and excess sorption isotherms were measured at 35 and 50 °C and pressure ranges of 0–200 bar, mimicking conditions of temperature and pressure in some of the currently active carbon storage sites (Kevin dome, Sleipner, Ketzin, Otway, Teapot dome). ...

Gernot Rother; Eugene S. Ilton; Dirk Wallacher; Thomas Hau?; Herbert T. Schaef; Odeta Qafoku; Kevin M. Rosso; Andrew R. Felmy; Elizabeth G. Krukowski; Andrew G. Stack; Nico Grimm; Robert J. Bodnar

2012-08-23T23:59:59.000Z

67

Single-crystal neutron diffraction studies on Ni-based metal-pnictide superconductor BaNi2As2  

SciTech Connect (OSTI)

We report the results of single-crystal neutron diffraction studies of the superconductor BaNi{sub 2}As{sub 2}. The experiments were performed on a tiny crystal of mass 0.8 mg at several temperatures between 20 and 200 K using the Single Crystal Diffractometer, SCD, at the Los Alamos Neutron Science Center. Above 130 K, BaNi{sub 2}As{sub 2} crystallizes in the tetragonal ThCr{sub 2}Si{sub 2} structure. Our neutron diffraction data corroborate a first-order structural transition around 130 K with a relatively large hysteresis of about 10K, in agreement with observations from bulk studies. The anisotropic thermal displacement coefficients are enhanced along c-axis approaching the transition, and a splitting is observed for in-plane type reflections below the transition, which is evidence for a change in crystal structure.

Kothapalli, Karunakar [Los Alamos National Laboratory; Ronning, F [Los Alamos National Laboratory; Bauer, E D [Los Alamos National Laboratory; Schultz, A J [Los Alamos National Laboratory; Nakotte, Heinz [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

68

In-Situ Neutron Diffraction Studies of Complex Hydrogen Storage Materials  

SciTech Connect (OSTI)

The thrust of this project was to investigate the structures of important materials with potential application to hydrogen storage, in an effort to meet the DOE goals for 2010 and 2015, namely 9% (wt) and 15% (wt) respectively. Unfortunately, no material has been found, despite the efforts of many laboratories, including our own, that achieves these goals in a reversible complex hydride such as ammonia borane (NH{sub 4}BH{sub 4}), and other ammonia based compounds, or with light hydrides such as LiBH{sub 4}, due either to their irreversibility or to the high decomposition temperatures and residual simple hydrides such as LiH from the decomposition of the last named compound. Nevertheless, several important technical goals have been accomplished that could be valuable to other DOE programs and would be available for collaborative research. These include the development of a high quality glove box with controlled (low) oxygen and water content, which we continue to employ for the synthesis of potential new materials (unfunded research) and the development of a high quality neutron diffraction furnace with controlled gas environment for studies of hydrogen uptake and loss as well as for studies with other gasses. This furnace was initially constructed with an alumina (Al{sub 2}O{sub 3}) center tube to contain the sample and the flowing gas. The heaters are located in the vacuum space outside the tube and it was found that, for the low temperatures required for the study of hydrogen storage materials, the heat transfer was too poor to allow good control. At temperatures in excess of about 400C (and up to more than 1200C) the heat transfer and control are excellent. For the lower temperatures, however, the center tube was replaced by stainless steel and temperature control to 1C became possible. The paired heaters, above and below the neutron beam window allowed control of the temperature gradient to a similar precision. The high temperature capability of the furnace should make it a very valuable resource for the study of oxides being considered for application to solid oxide fuel cells (SOFCs), in that materials can be studied at potential operating temperatures in both reducing and oxidizing environments to determine their stoichiometry, and lattice parameters. Our research, which was predicated, in part, on the use of hydrogenous samples (as opposed to deuteration), demonstrated that such studies are feasible and can yield high quality, refinable data. The precision of the refined hydrogen positions appears to be more than adequate for theory calculations (molecular modeling-thermodynamics) and the uncertainty is certainly less than that achieved by attempting to extrapolate the hydrogen positions from refined deuterium positions. In fact the 2008 annual report from the Institute Laue Langevin (ILL), the world's premier neutron scattering laboratory, highlights: Another trend is the increasing interest in hydrogen. This defies the widespread assumption that neutron diffraction experiments need to be done at deuterated samples. In situ experiments on phase transitions involving hydrogen and in particular on the real time behaviour of hydrogen-storage systems increase in number and scope. Our work in this area predates the ILL efforts be several years. Unfortunately, the productivity of our program was significantly curtailed by the unavailability of the MURR powder diffractometer for almost all of the second years of the project. The diffractometer was disassembled to allow partial extraction of the beam tube and replacement of the graphite element that is penetrated by the beam tube. Re-commissioning of the instrument was substantially delayed by errors of the MURR engineering staff, which failed to properly reinstall the sapphire filter that conditions the beam prior to the neutron monochromator, and reduces the radiological background to acceptable levels.

Yelon, William B.

2013-05-13T23:59:59.000Z

69

Neutron Diffraction Residual Strain Tensor Measurements Within The Phase IA Weld Mock-up Plate P-5  

SciTech Connect (OSTI)

Oak Ridge National Laboratory (ORNL) has worked with NRC and EPRI to apply neutron and X-ray diffraction methods to characterize the residual stresses in a number of dissimilar metal weld mockups and samples. The design of the Phase IA specimens aimed to enable stress measurements by several methods and computational modeling of the weld residual stresses. The partial groove in the 304L stainless steel plate was filled with weld beads of Alloy 82. A summary of the weld conditions for each plate is provided in Table 1. The plates were constrained along the long edges during and after welding by bolts with spring-loaded washers attached to the 1-inch thick Al backing plate. The purpose was to avoid stress relief due to bending of the welded stainless steel plate. The neutron diffraction method was one of the methods selected by EPRI for non-destructive through thickness strain and stress measurement. Four different plates (P-3 to P-6) were studied by neutron diffraction strain mapping, representing four different welding conditions. Through thickness neutron diffraction strain mappings at NRSF2 for the four plates and associated strain-free d-zero specimens involved measurement along seven lines across the weld and at six to seven depths. The mountings of each plate for neutron diffraction measurements were such that the diffraction vector was parallel to each of the three primary orthogonal directions of the plate: two in-plane directions, longitudinal and transverse, and the direction normal to the plate (shown in left figure within Table 1). From the three orthogonal strains for each location, the residual stresses along the three plate directions were calculated. The principal axes of the strain and stress tensors, however, need not necessarily align with the plate coordinate system. To explore this, plate P-5 was selected for examination of the possibility that the principal axes of strain are not along the sample coordinate system axes. If adequate data could be collected the goal would be to determine the strain tensor's orientation and magnitude of strain along each principle axis direction.

Hubbard, Camden R [ORNL

2011-09-01T23:59:59.000Z

70

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

71

Low-frequency Vibrational Anomalies in -Lactoglobulin: Contribution of Different Hydrogen Classes Revealed by Inelastic Neutron Scattering  

E-Print Network [OSTI]

Revealed by Inelastic Neutron Scattering A. Orecchini, A. Paciaroni, A. R. Bizzarri, and S. Cannistraro -lactoglobulin has been investigated by inelastic neutron scattering, on both dry and D2O-hydrated samples. Both typically accessible energy and momentum transfers, inelastic thermal neutron scattering is probably

Tuscia, Università Degli Studi Della

72

Ris-R-747(EN) Neutron and X-Ray Diffraction  

E-Print Network [OSTI]

describes X-ray and neutron scattering experiments per- formed on two examples of modulated structures is divided in three parts. A single crystal elastic neutron scattering experiment between 4.2 and 115 K has shift across the layers. A small-angle neutron scattering experiment has been performed on the mag

73

Pressure dependent diffraction and spectroscopy of a dimerized antiferromagnet  

SciTech Connect (OSTI)

We present pressure dependent neutron diffraction and inelastic neutron scattering measurements of the dimerized antiferromagnet Ba$_3$Mn$_2$O$_8$. The room temperature diffraction measurements reveal a linear decrease in lattice constant as a function of applied pressure. No structural transitions are observed. The low-temperature neutron spectroscopy measurements indicate a small change in magnetic scattering intensity in the vicinity of the spin gap for pressures up to $P=0.6$~kbar.

Stone, Matthew B [ORNL; Tulk, Christopher A [ORNL; dos Santos, Antonio M. [Oak Ridge National Laboratory (ORNL); Molaison, Jamie J [ORNL; Chang, S. [Ames Laboratory; Leo, J B [National Institute of Standards and Technology (NIST), Gaithersburg, MD; Samulon, Eric C [Stanford University; Shapiro, Max C [Stanford University; Fisher, Ian R [Stanford University

2011-01-01T23:59:59.000Z

74

A joint x-ray and neutron study on amicyanin reveals the role of protein dynamics in electron transfer  

SciTech Connect (OSTI)

The joint x-ray/neutron diffraction model of the Type I copper protein, amicyanin from Paracoccus denitrificans was determined at 1.8 {angstrom} resolution. The protein was crystallized using reagents prepared in D{sub 2}O. About 86% of the amide hydrogen atoms are either partially or fully exchanged, which correlates well with the atomic depth of the amide nitrogen atom and the secondary structure type, but with notable exceptions. Each of the four residues that provide copper ligands is partially deuterated. The model reveals the dynamic nature of the protein, especially around the copper-binding site. A detailed analysis of the presence of deuterated water molecules near the exchange sites indicates that amide hydrogen exchange is primarily due to the flexibility of the protein. Analysis of the electron transfer path through the protein shows that residues in that region are highly dynamic, as judged by hydrogen/deuterium exchange. This could increase the rate of electron transfer by transiently shortening through-space jumps in pathways or by increasing the atomic packing density. Analysis of C-H{hor_ellipsis}X bonding reveals previously undefined roles of these relatively weak H bonds, which, when present in sufficient number can collectively influence the structure, redox, and electron transfer properties of amicyanin.

Sukumar, N.; Mathews, F.S.; Langan, P.; Davidson, V.L. (Cornell); (UMMC); (WU-MED); (LANL)

2010-06-21T23:59:59.000Z

75

JOURNAL DE PHYSIQUE Colloque C 1, supplment au n 2-3, Tome 32, Fvrier-Mars 1971, page C 1 -503 NEUTRON DIFFRACTION, MOSSBAUER  

E-Print Network [OSTI]

in neutron scattering amplitudes of Ti and V (b = - 0.38 and - 0.05 respectively) and Ta (b = 0.70 x 10- 1 2.17 (*) With temperature factor B = 0.4 A. The large contribution of oxygen to the neutron scattering permits us to refine NEUTRON DIFFRACTION, MOSSBAUER AND MAGNETIC INVESTIGATION OF RUTILE-TYPE TANTALATES MTa04 (M = Ti, V, Cr

Boyer, Edmond

76

Neutron Scattering and Diffraction Studies of Fluids and Fluid-Solid Interactions  

Science Journals Connector (OSTI)

...structure, such as porous glasses (e.g., Vycor), xerogels, aerogels, and rocks. At the other end, there are materials characterized...Frielinghaus H (2006) Adsorption of supercritical CO2 in aerogels as studied by small-angle neutron scattering and neutron...

David R. Cole; Kenneth W. Herwig; Eugene Mamontov; John Z. Larese

77

Neutron diffraction studies of antiferromagnetism in manganous fluoride and some isomorphous compounds  

E-Print Network [OSTI]

. CALCULATED AND OBSERVED INTENSITIES MnF2..................53 VI. CALCULATED AND OBSERVED INTENSITIES FeF2..................57 VII. CALCULATED AND OBSERVED INTENSITIES CqF2..................62 VIII. CALCULATED AND OBSERVED INTENSITIES NiF2... 18. Diffraction Patterns from C0F2............................ 59 19. Saturation Curve of F2 in CoF0 and NiFo.................6l 100 2 2 20. NiF2 Diffraction Patterns................................0\\- 21. Saturation Curves for the Fluorides...

Erickson, Richard Ames

1952-01-01T23:59:59.000Z

78

Water–DNA interactions as studied by X–ray and neutron fibre diffraction  

Science Journals Connector (OSTI)

...over the A form by the pres- ence of excess ions in the fibre. This effect is most...Langridge, R. 1965 Fourier synthesis of lithium DNA part III: Hoogsteen models. J...diffraction study of a crystalline form of the lithium salt. J. Mol. Biol. 2, 1937. Langridge...

2004-01-01T23:59:59.000Z

79

Crystal structure of brucite-type cobalt hydroxide ?-Co{O(H,D)}2 — neutron diffraction, IR and Raman spectroscopy  

Science Journals Connector (OSTI)

The crystal structure of brucite-type Co(OD)2 (space group P3?ml, Z = 1, a = 317.79(4) pm and c = 464.2(1) pm, RI = 5.89%) has been refined by neutron powder diffraction studies on the basis of 671 observations and 44 reflections. Infrared and Raman spectra of cobalt hydroxide at different degrees of deuteration are presented and assigned to the internal, librational and translational modes. The D?O distance of 252.8 pm and the wavenumbers of the OH and OD stretching modes (3604 and 2665 cm?1, 90 K, mean values of the unit-cell group modes) do not exclude the formation of weak trifurcated hydrogen bonds. The librational and translational vibrations of Eu species are strongly coupled as shown by the respective isotopic shifts. A reassignment of the IR-allowed librations and lattice vibrations of transition metal brucite-type hydroxides is given.

Ch. Mockenhaupt; Th. Zeiske; H.D. Lutz

1998-01-01T23:59:59.000Z

80

High-pressure cell for neutron diffraction with in situ pressure control at cryogenic temperatures  

SciTech Connect (OSTI)

Pressure generation at cryogenic temperatures presents a problem for a wide array of experimental techniques, particularly neutron studies due to the volume of sample required. We present a novel, compact pressure cell with a large sample volume in which load is generated by a bellow. Using a supply of helium gas up to a pressure of 350 bar, a load of up to 78 kN is generated with leak-free operation. In addition, special fiber ports added to the cryogenic center stick allow for in situ pressure determination using the ruby pressure standard. Mechanical stability was assessed using finite element analysis and the dimensions of the cell have been optimized for use with standard cryogenic equipment. Load testing and on-line experiments using NaCl and BiNiO{sub 3} have been done at the WISH instrument of the ISIS pulsed neutron source to verify performance.

Jacobsen, Matthew K.; Ridley, Christopher J.; Bocian, Artur; Kamenev, Konstantin V., E-mail: k.kamenev@ed.ac.uk [School of Engineering and CSEC, University of Edinburgh, Edinburgh (United Kingdom); Kirichek, Oleg; Manuel, Pascal; Khalyavin, Dmitry [ISIS, Rutherford Appleton Laboratory, Harwell Oxford (United Kingdom)] [ISIS, Rutherford Appleton Laboratory, Harwell Oxford (United Kingdom); Azuma, Masaki [Materials and Structures Laboratory, Tokyo Institute of Technology, Tokyo (Japan)] [Materials and Structures Laboratory, Tokyo Institute of Technology, Tokyo (Japan); Attfield, J. Paul [School of Chemistry and CSEC, University of Edinburgh, Edinburgh (United Kingdom)] [School of Chemistry and CSEC, University of Edinburgh, Edinburgh (United Kingdom)

2014-04-15T23:59:59.000Z

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


81

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

82

Nanosecond molecular relaxations in lipid bilayers studied by high energy resolution neutron scattering and in-situ diffraction  

E-Print Network [OSTI]

We report a high energy-resolution neutron backscattering study to investigate slow motions on nanosecond time scales in highly oriented solid supported phospholipid bilayers of the model system DMPC -d54 (deuterated 1,2-dimyristoyl-sn-glycero-3-phoshatidylcholine), hydrated with heavy water. Wave vector resolved quasi-elastic neutron scattering (QENS) is used to determine relaxation times $\\tau$, which can be associated with different molecular components, i.e., the lipid acyl chains and the interstitial water molecules in the different phases of the model membrane system. The inelastic data are complemented both by energy resolved and energy integrated in-situ diffraction. From a combined analysis of the inelastic data in the energy and time domain, the respective character of the relaxation, i.e., the exponent of the exponential decay is also determined. From this analysis we quantify two relaxation processes. We associate the fast relaxation with translational diffusion of lipid and water molecules while the slow process likely stems from collective dynamics.

Maikel C. Rheinstädter; Tilo Seydel; Tim Salditt

2006-07-20T23:59:59.000Z

83

Combined Neutron and Synchrotron X-ray Diffraction Investigation of the BaCe0.85-xZrxY0.15O3-? (0.1 ? x ? 0.4) Proton Conductors  

Science Journals Connector (OSTI)

Combined Neutron and Synchrotron X-ray Diffraction Investigation of the BaCe0.85-xZrxY0.15O3-? (0.1 ? x ? 0.4) Proton Conductors ... § Laboratory for Neutron Scattering, ETHZ and PSI, CH-5232, Villigen PSI, Switzerland ... Combined neutron and X-ray synchrotron diffraction have been used to unveil the structural properties for the BaCe0.85-xZrxY0.15O3-? ...

Lorenzo Malavasi; Cristina Tealdi; Clemens Ritter; Vladimir Pomjakushin; Fabia Gozzo; Yuri Diaz-Fernandez

2011-02-03T23:59:59.000Z

84

JOURNAL DE PHYSIQUE Colloque C I, supplPment au no 2-3, Tome 32, FPvrier-Mars 1971,page C 1 -70 NEUTRON DIFFRACTION STUDY OF SHORT RANGE ORDER  

E-Print Network [OSTI]

cross-section for neutron scattering is do -dQ = m~ m~(b, - bd2 i=o ai exp i(K.Ri) (I) where ai = 1 - Pi NEUTRON DIFFRACTION STUDY OF SHORT RANGE ORDER IN r-iMnNi P. WELLS and J. H. SMITH Physics Department un moment magnetique par atome de manganese de 1,5 +. 0,l WB. Une etude par diffraction de neutrons r

Boyer, Edmond

85

JOURNAL DE PHYSIQUE CoZZoque C8, suppZ6ment au n08, Tome 41, aoGt 1980, page C8-163 STUDY OF LIQUID NICKEL-VANADIUM ALLOYS BY NEUTRON DIFFRACTION AND MODEL SIMULATION  

E-Print Network [OSTI]

, 28 i s the scattering angle, X the neutron wave- length, Q = 4n the modulus of the scattering vector NICKEL-VANADIUM ALLOYS BY NEUTRON DIFFRACTION AND MODEL SIMULATION J.L. Lemarchand, J. Bletry and P with model c a l c u l a t i o ~can lead to a quantitative interpreta- tion. In this paper, neutron

Boyer, Edmond

86

A Novel In-situ Electrochemical Cell for Neutron Diffraction Studies of Phase Transitions in Small Volume Electrodes of Li-ion Batteries  

SciTech Connect (OSTI)

The design and performance of a novel in-situ electrochemical cell that greatly facilitates the neutron diffraction study of complex phase transitions in small volume electrodes of Li-ion cells, is presented in this work. Diffraction patterns that are Rietveld-refinable could be obtained simultaneously for all the electrodes, which demonstrates that the cell is best suited to explore electrode phase transitions driven by the lithiation and delithiation processes. This has been facilitated by the use of single crystal (100) Si sheets as casing material and the planar cell configuration, giving improved signal-to-noise ratio relative to other casing materials. The in-situ cell has also been designed for easy assembly and to facilitate rapid experiments. The effectiveness of cell is demonstrated by tracking the neutron diffraction patterns during the charging of graphite/LiCoO2 and graphite/LiMn2O4 cells. It is shown that good quality neutron diffraction data can be obtained and that most of the finer details of the phase transitions, and the associated changes in crystallographic parameters in these electrodes, can be captured.

Vadlamani, Bhaskar S [ORNL; An, Ke [ORNL; Jagannathan, M. [University of Utah; Ravi Chandran, K. [University of Utah

2014-01-01T23:59:59.000Z

87

Development of a Neutron Diffraction Based Experiemental Capability for Investigating Hydraulic Fracturing for EGS-like Conditions  

SciTech Connect (OSTI)

Hydraulic fracturing to enhance formation permeability is an established practice in the Oil & Gas (O&G) industry and is expected to be an enabler for EGS. However, it is rarely employed in conventional geothermal systems and there are significant questions regarding the translation of practice from O&G to both conventional geothermal and EGS applications. Lithological differences(sedimentary versus crystalline rocks, significantly greater formation temperatures and different desired fracture characteristics are among a number of factors that are likely to result in a gap of understanding of how to manage hydraulic fracturing practice for geothermal. Whereas the O&G community has had both the capital and the opportunity to develop its understanding of hydraulic fracturing operations empirically in the field as well through extensive R&D efforts, field testing opportunities for EGS are likely to be minimal due to the high expense of hydraulic fracturing field trials. A significant portion of the knowledge needed to guide the management of geothermal/EGS hydraulic fracturing operations will therefore likely have to come from experimental efforts and simulation. This paper describes ongoing efforts at Oak Ridge National Laboratory (ORNL) to develop an experimental capability to map the internal stresses/strains in core samples subjected to triaxial stress states and temperatures representative of EGS-like conditions using neutron diffraction based strain mapping techniques. This capability is being developed at ORNL\\'s Spallation Neutron Source, the world\\'s most powerful pulsed neutron source and is still in a proof of concept phase. A specialized pressure cell has been developed that permits independent radial and axial fluid pressurization of core samples, with axial flow through capability and a temperature rating up to 300 degrees C. This cell will ultimately be used to hydraulically pressurize EGS-representative core samples to conditions of imminent fracture and map the associated internal strain states of the sample. This will hopefully enable a more precise mapping of the rock material failure envelope, facilitate a more refined understanding of the mechanism of hydraulically induced rock fracture, particularly in crystalline rocks, and serve as a platform for validating and improving fracture simulation codes. The elements of the research program and preliminary strain mapping results of a Sierra White granite sample subjected only to compressive loading will be discussed in this paper.

Polsky, Yarom [ORNL] [ORNL; Anovitz, Lawrence {Larry} M [ORNL; An, Ke [ORNL] [ORNL; Carmichael, Justin R [ORNL] [ORNL; Bingham, Philip R [ORNL] [ORNL; Dessieux Jr, Luc Lucius [ORNL] [ORNL

2013-01-01T23:59:59.000Z

88

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

E-Print Network [OSTI]

Diffraction patterns of electrons are believed to resemble those of electromagnetic waves (EMW). I performed a series of experiments invoked to show that the periodicity of peaks in the diffraction diagram of electrons is concerned with the periodicity of the arrangement of scattering centers in the diffraction grating in combination with the supposed character of the spatial structure of the electron as a system of regularly spaced concentric shells of elasticity. I started from the experiment on the diffraction of electrons and EMWs at the sharp edge of the opaque half-plane. This simple scattering configuration enabled me to discriminate between the re-radiation mechanism of the wave diffraction and ricochet scattering of electrons on the edge of the half-plane. Then I made experiments with scattering on composite objects proceeding step by step from a single straight edge to a couple of edges (one slit) and then to four edges (two slits). Thus I succeeded in interpretation of the double-slit diffraction (four straight edges) in terms of the scattering on a single edge. I managed also to observe the electron's trajectory. Equipping the slit's edge with a semiconductor sensors I registered the passing of the electron through the slit detecting simultaneously a weaker signal at another slit. This technique appeared not to destroy or disturb the "interference" pattern. Closing one slit by inserting therein a transparent for EMWs piece of dielectric I have found that the scattering pattern beneath this slit vanishes while the scattering pattern under the open slit remains as before when both slits were open. This experiment indicates that the electron "interferes" with its electromagnetic component passed via the slit plugged by the transparent for it dielectric.

Victor V. Demjanov

2010-02-20T23:59:59.000Z

89

Neutron diffraction study of the formation of ordered antiphase domains in cubic titanium carbide TiC{sub 0.60}  

SciTech Connect (OSTI)

A series of superstructural reflections (described within the sp. gr. Fd3m) are found to be split into three symmetric parts in the neutron powder diffraction pattern of titanium carbide TiC{sub 0.60} annealed at a temperature of 600 Degree-Sign C. No splitting of superstructural reflections is observed in the neutron diffraction pattern of TiC{sub 0.60} annealed at relatively high temperatures (780 Degree-Sign C). This phenomenon can be explained by that fact that the ordering of carbon atoms at relatively high temperatures (780 Degree-Sign C) is accompanied by the formation of randomly oriented rather large antiphase domains (APDs) (450 A). At relatively low temperatures (600 Degree-Sign C), stacking faults arise in the arrangement of partially ordered carbon atoms. In this case, relatively small ordered APDs (290 A) are formed, along with disordered ones.

Khidirov, I., E-mail: khidirov@inp.uz; Parpiev, A. S. [Academy of Sciences of Uzbekistan, Institute of Nuclear Physics (Uzbekistan)

2013-05-15T23:59:59.000Z

90

Powder Diffraction  

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

Powder Diffraction Powder Diffraction Ashfia Huq Spallation Neutron Source Oak Ridge National Laboratory 2 Managed by UT-Battelle for the U.S. Department of Energy Bragg's law W.H. Bragg (1862-1942) W.L. Bragg (1890-1971) *Zinc Blend (fcc not sc) *NaCl (not molecular) *Diamond (two overlapping fcc lattice) Shared 1915 Nobel Prize 3 Managed by UT-Battelle for the U.S. Department of Energy Where are the atoms? X-ray: (l : 10 -9 m - 10 -11 m) l[Å] = 12.398/E ph [keV] Source: * Lab diffractometers * Synchrotron Sources Neutron: (thermal l : 1-4Å) E n [meV] =81.89/ l 2 [Å] Source: * Reactors (fission) * Spallation Source We need wavelength (l) ~ Object size (for condensed matter that is Å) 4 Managed by UT-Battelle for the U.S. Department of Energy

91

Two-dimensional position-sensitive gaseous detectors for high-resolution neutron and X-ray diffraction  

Science Journals Connector (OSTI)

Two-dimensional position-sensitive gaseous detectors have been developed at the Geesthacht Neutron Facility (GeNF) for high-resolution...2, 3He/CF4 and Xe/CO2, respectively. One neutron detector is used at the AR...

M. Marmotti; M. Haese-Seiller; R. Kampmann

2002-12-01T23:59:59.000Z

92

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

93

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. Rühm; D. K. Satapathy; V. Hinkov; B. Keimer

2012-11-08T23:59:59.000Z

94

A high temperature neutron diffraction study of the double perovskite Ba{sub 2}{sup 154}SmMoO{sub 6}  

SciTech Connect (OSTI)

Ba{sub 2}LnMoO{sub 6} double perovskites have been recently shown to display a wide range of interesting magnetic and structural properties; Ba{sub 2}{sup 154}SmMoO{sub 6} exhibits simultaneous antiferromagnetic order and a Jahn-Teller distortion. Here we report a high temperature neutron diffraction study of Ba{sub 2}{sup 154}SmMoO{sub 6} from 353 to 877 K. The results evidence a tetragonal to cubic phase transition at 423 K. Above this temperature the thermal displacement parameters of the oxygen atoms are modelled anisotropically as a result of a transverse vibration of the bridging oxygen. A smooth increase in the cell parameter a is observed with temperature for Ba{sub 2}{sup 154}SmMoO{sub 6}. - Graphical abstract: The high temperature crystal structure of Ba{sub 2}{sup 154}SmMoO{sub 6} evidencing a transverse oxygen vibration. Highlights: Black-Right-Pointing-Pointer A high temperature neutron diffraction study has been performed on an isotopically enriched sample of Ba{sub 2}{sup 154}SmMoO{sub 6}. Black-Right-Pointing-Pointer A cubic-tetragonal phase transition occurs below 423 K. Black-Right-Pointing-Pointer The thermal displacement parameters of the bridging oxygens are modelled anisotropically. Black-Right-Pointing-Pointer There is a transverse vibration of the bridging oxygen.

Wallace, Thomas K. [Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE (United Kingdom)] [Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE (United Kingdom); Ritter, Clemens [Institut Laue Langevin, 6 rue Jules Horowitz, BP 156, F-38042 Grenoble Cedex 9 (France)] [Institut Laue Langevin, 6 rue Jules Horowitz, BP 156, F-38042 Grenoble Cedex 9 (France); Mclaughlin, Abbie C., E-mail: a.c.mclaughlin@abdn.ac.uk [Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE (United Kingdom)

2012-12-15T23:59:59.000Z

95

Equilibrium Structure of a Triblock Copolymer System Revealed by Mesoscale Simulation and Neutron Scattering  

SciTech Connect (OSTI)

We have performed both mesoscale simulations and neutron scattering experiments on Pluronic L62, a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer system in aqueous solution. The influence of simulation variables such PEO/PPO block ratio, interaction parameters, and coarse-graining methods is extensively investigated by covering all permutations of parameters found in the literatures. Upon increasing the polymer weight fraction from 50 wt% to 90 wt%, the equilibrium structure of the isotropic, reverse micellar, bicontinuous, worm-like micelle network, and lamellar phases are respectively predicted from the simulation depending on the choices of simulation parameters. Small angle neutron scattering (SANS) measurements show that the same polymer systems exhibit the spherical micellar, lamellar, and reverse micellar phases with the increase of the copolymer concentration at room temperature. Detailed structural analysis and comparison with simulations suggest that one of the simulation parameter sets can provide reasonable agreement with the experimentally observed structures.

Do, Changwoo [ORNL] [ORNL; Chen, Wei-Ren [ORNL] [ORNL; Hong, Kunlun [ORNL] [ORNL; Smith, Gregory Scott [ORNL] [ORNL

2013-01-01T23:59:59.000Z

96

LJournal of Alloys and Compounds 291 (1999) 94101 The simultaneous powder X-ray and neutron diffraction refinement of two  

E-Print Network [OSTI]

melting of metals in the The intermetallic ternary transition metal nitrides and presence of carbon]. These phases are of interest decomposition of transition metal tris­ethylenediamine to the solid state chemist diffraction refinement of two h-carbide type nitrides, Fe Mo N and Co Mo N, prepared by3 3 3 3 ammonolysis

zur Loye, Hans-Conrad

97

Agglomeration and sintering in annealed FePt nanoparticle assemblies studied by small angle neutron scattering and x-ray diffraction  

Science Journals Connector (OSTI)

In this work we give a detailed account of complementary small angle neutron scattering and x-ray diffraction studies of polymer mediated, self-assembled FePt nanoparticle arrays as a function of annealing temperature. The combination of these two techniques provides significantly greater physical insight than is available using either individually. Since both methods integrate over a large number of particles statistically meaningful data can be obtained in contrast to imaging techniques where typically only small areas are analyzed. The data show that the median particle size increases with annealing at temperatures of 580°C and above. The data also demonstrate that the distribution of particle diameters is significant and increases with annealing temperature. These results allow a comprehensive structural model of the annealed assemblies to be developed in terms of particle sintering and agglomeration. This enhanced understanding will allow new strategies to be pursued in realizing the potential of nanoparticle assemblies as a monodispersed data storage medium.

T. Thomson; S. L. Lee; M. F. Toney; C. D. Dewhurst; F. Y. Ogrin; C. J. Oates; S. Sun

2005-08-19T23:59:59.000Z

98

Principal interactions in the magnetic system Fe{sub 1-x}Co{sub x}Si: Magnetic structure and critical temperature by neutron diffraction and SQUID measurements  

SciTech Connect (OSTI)

The compound Fe{sub 1-x}Co{sub x}Si is a good representative for a cubic magnet with Dzyaloshinskii-Moriya interaction. On the basis of the neutron diffraction and superconducting quantum interference device measurements, we built the H-T phase diagram for the compound with different x from 0.1 to 0.7. The same set of parameters governs the magnetic system for different x. These parameters are well interpreted in the framework of the recently developed theory [S. V. Maleyev, Phys. Rev. B 73, 174402 (2006)]. As a result, the spin-wave stiffness, the Dzyaloshinskii constant, the anisotropic exchange constant, and the spin-wave gap caused by the Dzyaloshinskii interaction have been obtained and plotted as a function of x. The changes of the magnetic structure with x can be well interpreted on the basis of our findings.

Grigoriev, S. V.; Maleyev, S. V.; Dyadkin, V. A. [Petersburg Nuclear Physics Institute, Gatchina, 188300 St. Petersburg (Russian Federation); Menzel, D.; Schoenes, J. [Institut fuer Physik der Kondensierten Materie, TU Braunschweig, 38106 Braunschweig (Germany); Eckerlebe, H. [GKSS Forschungszentrum, 21502 Geesthacht (Germany)

2007-09-01T23:59:59.000Z

99

Neutron reflectrometry reveals the internal structure of natural organic matter deposited onto an aluminum oxide  

SciTech Connect (OSTI)

Organic carbon (OC) stabilization in soils plays a significant role in the global C cycle, therefore understanding the structure and function of the OC soil mineral interface is of high importance. To study the interface, films of simple OC compounds and natural organic matter (NOM) were deposited onto a soil mineral analogue (Al2O3) using spin coating and were exposed to humidity. The thickness, density and structure of the films were studied using a depth-sensitive, nano-scale technique of neutron reflectometry. A single homogenous layer was observed when NOM and glucose (GL) were adsorbed onto Al2O3. However, when stearic acid (SA) was added to either NOM or GL, separate layers attributed to SA and either NOM or GL were detected. The formation of distinct, immiscible layers is due to insolubility of SA with NOM and GL. In contrast, GL and NOM are both water-soluble, and therefore soluble with each other, forming a homogenous layer on the mineral surface. Our results suggest that the extent of complex layering formed on the OC mineral interface may depend on the relative solubility of the compounds.

Mayes, Melanie [ORNL; Jagadamma, Sindhu [ORNL; Ambaye, Haile Arena [ORNL; Petridis, Loukas [ORNL; Lauter, Valeria [ORNL

2013-01-01T23:59:59.000Z

100

Neutron reflectometry reveals the internal structure of organic compounds deposited on aluminum oxide  

Science Journals Connector (OSTI)

Organic carbon (OC) stabilization in soils plays a significant role in the global C cycle, therefore understanding the structure and function of the OC–soil mineral interface is of high importance. To study the interface, films of simple OC compounds and natural organic matter (NOM) were deposited onto a soil mineral analogue (Al2O3) using spin coating and were exposed to humidity. The thickness, density and structure of the films were studied using a depth-sensitive, nano-scale technique of neutron reflectometry. A single homogenous layer was observed when NOM and glucose (GL) were adsorbed onto Al2O3. However, when stearic acid (SA) was added to either NOM or GL, separate layers attributed to SA and either NOM or GL were detected. The formation of distinct, immiscible layers is due to insolubility of SA with NOM and GL. In contrast, GL and NOM are both water-soluble, and therefore soluble with each other, forming a homogenous layer on the mineral surface. Our results suggest that the extent of complex layering formed on the OC–mineral interface may depend on the relative solubility of the compounds.

Melanie Mayes; Sindhu Jagadamma; Haile Ambaye; Loukas Petridis; Valeria Lauter

2013-01-01T23:59:59.000Z

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

Features of Diffraction Dissociation of Neutrons in np Collisions at 50-300 GeV/c  

Science Journals Connector (OSTI)

We present preliminary results from an investigation of the reaction n+p?(p?-)+p for neutron momenta in the range of 50 to 300 GeV/c. The data display a strong correlation between the mass of the p?- system and the four-momentum transferred in the production. Cross sections for producing low-mass (p?-) systems are independent of energy to within 10% accuracy.

J. Biel; E. Bleser; T. Ferbel; D. Freytag; B. Gobbi; L. Kenah; J. Rosen; R. Ruchti; P. Slattery; D. Underwood

1976-03-08T23:59:59.000Z

102

Closed three-center carbon-hydrogen-metal interaction. A neutron diffraction study of HFe/sub 4/(eta/sup 2/-CH)(CO)/sub 12/  

SciTech Connect (OSTI)

The crystal and molecular structure of HFe/sub 4/(eta/sup 2/-CH)(CO)/sub 12/ has been determined at 173 K by x-ray diffraction and at 26 K by neutron diffraction techniques. The complex crystallized in the monoclinic space group with unit-cell dimensions of a = 8.694 (1) A, b = 32.920 (6) A, c = 13.757 (3) A, ..beta.. = 112.95 (1)/sup 0/, and V = 3625.7 A/sup 3/ at 26 K with Z = 8. Full-matrix least-squares refinement of the neutron data gave R(F/sub 0/) = 0.060 and R/sub w/(F/sub 0//sup 2/) = 0.079 for all 5663 data. The goodness-of-fit, with a data to parameter ratio of 10.1:1, was 1.876. The only significant structural differences in the two unique molecules of the asymmetric unit were the intermolecular contacts. The iron atoms were arranged in a butterfly conformation with a C-H group nestled between the wings. The most significant structural finding was a true C-H-Fe three-center interaction, containing both a very short Fe-H distance of 1.753 (4) A (1.747 (4) A, second molecule) and the longest reported C-H bond distance, 1.191 (4) A (1.176 (4) A). The results have been discussed in relation to the origin and nature of this C-H-Fe three-center interaction, the activation of C-H bonds in catalysis, and possible eta/sup 2/ bonding of a C-H fragment at a metal surface.

Beno, M.A. (Argonne National Lab., IL); Williams, J.M.; Tachikawa, M.; Muetterties, E.L.

1981-03-25T23:59:59.000Z

103

Neutron Diffraction Studies of a Class A beta-Lactamase Toho-1 E166A/R274N/R276N Triple Mutant  

SciTech Connect (OSTI)

beta-Lactam antibiotics have been used effectively over several decades against many types of bacterial infectious diseases. However, the most common cause of resistance to the beta-lactam antibiotics is the production of beta-lactamase enzymes that inactivate beta-lactams by rapidly hydrolyzing the amide group of the beta-lactam ring. Specifically, the class A extended-spectrum beta-lactamases (ESBLs) and inhibitor-resistant enzymes arose that were capable of hydrolyzing penicillins and the expanded-spectrum cephalosporins and monobactams in resistant bacteria, which lead to treatment problems in many clinical settings. A more complete understanding of the mechanism of catalysis of these ESBL enzymes will impact current antibiotic drug discovery efforts. Here, we describe the neutron structure of the class A, CTX-M-type ESBL Toho-1 E166A/R274N/R276N triple mutant in its apo form, which is the first reported neutron structure of a beta-lactamase enzyme. This neutron structure clearly reveals the active-site protonation states and hydrogen-bonding network of the apo Toho-1 ESBL prior to substrate binding and subsequent acylation. The protonation states of the active-site residues Ser70, Lys73, Ser130, and Lys234 in this neutron structure are consistent with the prediction of a proton transfer pathway from Lys73 to Ser130 that is likely dependent on the conformation of Lys73, which has been hypothesized to be coupled to the protonation state of Glu166 during the acylation reaction. Thus, this neutron structure is in agreement with a proposed mechanism for acylation that identifies Glu166 as the general base for catalysis.

Blakeley, Matthew P. [Institut Laue-Langevin (ILL); Chen, Yu [ORNL; Afonine, Pavel [Lawrence Berkeley National Laboratory (LBNL)

2010-01-01T23:59:59.000Z

104

Heterolytic Cleavage of Hydrogen by an Iron Hydrogenase Model: An Fe-H - - - H-N Dihydorgen Bond Characterized by Neutron Diffraction  

SciTech Connect (OSTI)

Use of hydrogen as a fuel by [FeFe]-hydrogenase enzymes in nature requires heterolytic cleavage of the H-H bond into a proton (H+) and hydride (H-), a reaction that is also a critical step in homogeneous catalysts for hydrogenation of C=O and C=N bonds. An understanding of the catalytic oxidation of H2 by hydrogenases provides insights into the design of synthetic catalysts that are sought as cost-effective alternatives to the use of the precious metal platinum in fuel cells. Crystallographic studies on the [FeFe]-hydrogenase enzyme were critical to understanding of its reactivity, but the key H-H cleavage step is not readily observed experimentally in natural hydrogenases. Synthetic biomimics have provided evidence for H2 cleavage leading to hydride transfer to the metal and proton transfer to an amine. Limitations on the precise location of hydrogen atoms by x-ray diffraction can be overcome by use of neutron diffraction, though its use is severely limited by the difficulty of obtaining suitable crystals and by the scarcity of neutron sources. Here we show that an iron complex with a pendant amine in the diphosphine ligand cleaves hydrogen heterolytically under mild conditions, leading to [CpC5F4NFeH(PtBu2NtBu2H)]+BArF4-, [PtBu2NtBu2 = 1,5-di(tert-butyl)-3,7-di(tert-butyl)-1,5-diaza-3,7-diphosphacyclooctane; ArF = 3,5-bis(trifluoromethyl)phenyl]. The Fe-H- - - H-N moiety has a strong dihydrogen bond, with a remarkably short H • • • H distance of 1.489(10) Å between the protic N-H?+ and hydridic Fe-H?-. The structural data for [CpC5F4NFeH(PtBu2NtBu2H)]+ provide a glimpse of how the H-H bond is oxidized or generated in hydrogenase enzymes, with the pendant amine playing a key role as a proton relay. The iron complex [CpC5F4NFeH(PtBu2NtBu2H)]+BArF4- is an electrocatalyst for oxidation of H2 (1 atm) at 22 °C, so the structural data are obtained on a complex that is a functional model for catalysis by [FeFe]-hydrogenase enzymes. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy.

Liu, Tianbiao L.; Wang, Xiaoping; Hoffmann, Christina; DuBois, Daniel L.; Bullock, R. Morris

2014-05-19T23:59:59.000Z

105

Magnetic Proximity Effects in V/Fe Superconductor/Ferromagnet Single Bilayer Revealed by Waveguide-Enhanced Polarized Neutron Reflectometry  

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Polarized neutron reflectometry is used to study the magnetic proximity...T C manifested in a systematic change in the height and width of the waveguide resonance peak. Upon increasing the tempera...

Yu. N. Khaydukov; V. L. Aksenov…

2011-01-01T23:59:59.000Z

106

Magnetic structure of Fe{sub 1-x}Co{sub x}Si in a magnetic field studied via small-angle polarized neutron diffraction  

SciTech Connect (OSTI)

The magnetic structure of Fe{sub 1-x}Co{sub x}Si single crystals with x=0.10,0.15,0.20,0.50 has been studied by small angle polarized neutron diffraction and superconducting quantum interference device measurements. Experiments have shown that in zero field the compounds with x=0.1,0.15 have a well-defined tendency to order in the one-handed spiral along <100> axes due to the anisotropic exchange, that, however, decreases with increasing Co concentration x. The magnetic structure of Fe{sub 1-x}Co{sub x}Si with x=0.2,0.5 consists of spiral domains with randomly oriented spiral wave vector k. The applied magnetic field produces a single domain helix oriented along the field. The process of the reorientation starts at the field H{sub C1}. Further increase of the field leads to a magnetic phase transition from a conical to a ferromagnetic state near H{sub C2}. In the critical range near T{sub C} the integral intensity of the Bragg reflection shows a well-pronounced minimum at H{sub fl} attributed to a k flop of the helix wave vector. On the basis of our experiments we built the H-T phase diagram for each compound. It is shown that the same set of the parameters governs the magnetic properties of these compounds k, H{sub C1}, H{sub fl}, and H{sub C2}. Our experimental findings are well interpreted in the framework of a recently developed theory [Phys. Rev. B 73, 174402 (2006)] for cubic magnets with Dzyaloshinskii-Moriya (DM) interaction. In particular, the theory suggests an additional quantum term in the magnetic susceptibility caused by the DM interaction which is in good agreement with the experiment.

Grigoriev, S. V.; Dyadkin, V. A.; Chetverikov, Yu. O.; Okorokov, A. I.; Maleyev, S. V. [Petersburg Nuclear Physics Institute, Gatchina, 188300 St-Petersburg (Russian Federation); Menzel, D.; Schoenes, J. [Institut fuer Physik der Kondensierten Materie, Technische Universitaet Braunschweig, D-38106 Braunschweig (Germany); Eckerlebe, H. [GKSS Forschungszentrum, 21502 Geesthacht (Germany)

2007-12-01T23:59:59.000Z

107

Neutron diffraction structural study of pyroelectric Li/sub 2/SO/sub 4/xH/sub 2/O at 293, 80, and 20 K  

SciTech Connect (OSTI)

Lithium sulfate monohydrate has been studied at 293, 80, and 20 K by neutron diffraction using the same ground spherical crystal. Li/sub 2/SO/sub 4/xH/sub 2/O is monoclinic, space group P2/sub 1/, with lattice dimensions at 293 K of a = 5.450(3), b = 4.872(3), c = 8.164(4) A, ..beta.. = 107.31(3)/sup 0/; at 80 K: a = 5.449(2), b = 4.832(2), c = 8.141(2) A, ..beta.. = 107.21(1)/sup 0/; and at 20 K: a = 5.449(2), b = 4.832(2), c = 8.137(2) A, ..beta.. = 107.19(1)/sup 0/. There are two formula units in the unit cell. Least-squares refinement based on 1749 (293 K), 1712 (80 K), and 880 (20 K) reflections gave final R(F) values of 0.022, 0.016, and 0.014, respectively. All structure factors were corrected for thermal diffuse scattering. A Gram--Charlier expansion of the probability density function was used to describe the thermal vibrations of the water molecule which at 293 K are consistent with a previously postulated flipping motion. The O(W)xxxO(W) hydrogen bond distance is 0.091(3) A shorter and the O(W)xxxO(W)xxxO(W) angle is 3.9(1)/sup 0/ larger at 20 K than at 293 K: the O(W)xxxO(1) distance to a sulfate oxygen is 0.041(3) A shorter. Both kinds of hydrogen bonds are weak and bent.

Lundgren, J.; Kvick; Karppinen, M.; Liminga, R.; Abrahams, S.C.

1984-01-01T23:59:59.000Z

108

Cryogenic neutron protein crystallography: routine methods and potential benefits  

Science Journals Connector (OSTI)

This article highlights routine methods and the benefits of collecting cryogenic macromolecular neutron diffraction data.

Coates, L.

2014-06-14T23:59:59.000Z

109

Observations of a dynamical-to-kinematic diffraction transition in plastically deformed polycrystalline intermetallic YCu  

SciTech Connect (OSTI)

Unlike most intermetallic compounds, polycrystalline YCu, a B2 (CsCl-type) intermetallic, is ductile at room temperature. The mechanisms for this behavior are not fully understood. In situ neutron diffraction was used to investigate whether a stress-induced phase transformation or twinning contribute to the ductility; however, neither mechanism was found to be active in YCu. Surprisingly, this study revealed that the intensities of the diffraction peaks increased after plastic deformation. It is thought that annealing the samples created nearly perfect crystallinity, and subsequent deformation reduced this high degree of lattice coherency, resulting in a modified mosaic structure that decreased or eliminated the extinction effect. Analysis of changes in diffraction peak intensity showed a region of primary plasticity that exhibits significant changes in diffraction behavior. Fully annealed samples initially contain diffracting volumes large enough to follow the dynamical theory of diffraction. When loaded beyond the yield point, dislocation motion disrupts the lattice perfection, and the diffracting volume is reduced to the point that diffraction follows the kinematic theory of diffraction. Since the sample preparation and deformation mechanisms present in this study are common in numerous material systems, this dynamical to kinematic diffraction transition should also be considered in other diffraction experiments. These measurements also suggest the possibility of a new method of investigating structural characteristics. (C) 2014 Published by Elsevier Ltd. on behalf of Acta Materialia Inc.

Williams, Scott H. [Ames Laboratory; Brown, Donald W. [Los Alamos National Laboratory; Clausen, Bjorn [Los Alamos National Laboratory; Russell, Alan [Ames Laboratory; Gschneidner Jr., Karl A. [Ames Laboratory

2014-03-01T23:59:59.000Z

110

Crystal structures and thermal expansion of -MgSO4 and -MgSO4 from 4.2 to 300 K by neutron powder diffraction  

Science Journals Connector (OSTI)

Powder neutron refinements of two MgSO4 polymorphs are presented, and their highly anisotropic thermal expansivity is analysed using a Debye model.

Fortes, A.D.

2007-07-13T23:59:59.000Z

111

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

112

Small-angle neutron scattering reveals the assembly mode and oligomeric architecture of TET, a large, dodecameric aminopeptidase  

Science Journals Connector (OSTI)

The present work illustrates that small-angle neutron scattering, deuteration and contrast variation, combined with in vitro particle reconstruction, constitutes a very efficient approach to determine subunit architectures in large, symmetric protein complexes. In the case of the 468 kDa heterododecameric TET peptidase machine, it was demonstrated that the assembly of the 12 subunits is a highly controlled process and represents a way to optimize the catalytic efficiency of the enzyme.

Appolaire, A.

2014-10-23T23:59:59.000Z

113

Neutron diffraction and specific heat studies on the magnetic ordering in the [Fe{sup II}({delta})Fe{sup II}({lambda})(ox){sub 2}(Phen){sub 2}]{sub n} molecular magnet  

SciTech Connect (OSTI)

The magnetic characteristics of the molecular magnet [Fe{sup II}({delta})Fe{sup II}({lambda})(ox){sub 2}(Phen){sub 2}]{sub n}, having chemical formula C{sub 28}H{sub 16}Fe{sub 2}N{sub 4}O{sub 8} for unity, has been studied by magnetization, neutron diffraction, and field-dependent specific heat-measurements. In the high-temperature regime (T>T{sub m}), the one-dimensional Ising chain model with alternate Lande factors is applied to describe its quasiferrimagnetic behavior as temperature approaches T{sub m}. In the low-temperature region (Tneutron diffraction study. The field-dependent {lambda}-type anomaly of specific heat indicates that applying a magnetic field raises magnetic ordering temperature. An additional small anomaly in specific heat is also seen below T{sub m}, which could be due to the zero-field splitting caused by the internal crystal field.

Ho, C. J.; Her, J. L.; Sun, C. P.; Huang, C. L.; Chou, C. C.; Yang, H. D. [Department of Physics, Center of Nanoscience and Nanotechnology, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Yang, C. C.; Li, W. H. [Department of Physics and Center for Neutron Beam Applications, National Central University, Chung-Li 32054, Taiwan (China); Li Lulin; Lin, K. J. [Department of Chemistry, Center of Nanoscience and Nanotechnology, National Chung-Hsing University, Taichung 402, Taiwan (China); Lynn, J. W. [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

2007-12-01T23:59:59.000Z

114

Small-angle neutron scattering and neutron reflectometry  

Science Journals Connector (OSTI)

Diffraction methods, interpreted loosely, could be applied to the techniques of wide-angle X-ray scattering, small-angle X-ray scattering, electron diffraction, small-angle neutron scattering, small-angle light s...

R. W. Richards

1993-01-01T23:59:59.000Z

115

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

116

The P-V-T equation of state of D2O ice VI determined by neutron powder diffraction in the range 0 < P < 2.6 GPa and 120 < T < 330 K, and the isothermal equation of state of D2O ice VII from 2 to 7 GPa at room temperature  

Science Journals Connector (OSTI)

Ice VI is an important rock-forming mineral phase in icy planetary bodies; the pressure and temperature dependence of its density have been measured using powder neutron diffraction, throughout the high-pressure stability field, to obtain an accurate equation of state parameterization. These data are used to derive other thermodynamic quantities of use in planetary modelling.

Fortes, A.D.

2012-05-16T23:59:59.000Z

117

Coherence lengths and neutron optics  

Science Journals Connector (OSTI)

The dynamical diffraction of divergent beams and its application to neutron interferometry are considered. The coherence properties of thermal neutrons are studied, and it is shown that the extreme anisotropy of dynamically diffracted wave packets should be included in the discussion of coherence lengths. Finally, the mechanism leading to a nondispersive phase shift is investigated.

D. Petrascheck

1987-05-01T23:59:59.000Z

118

Synchrotron and neutron powder diffraction study of phase transition in weberite-type Nd[subscript 3]NbO[subscript 7] and La[subscript 3]NbO[subscript 7  

SciTech Connect (OSTI)

La{sub 3}NbO{sub 7} and Nd{sub 3}NbO{sub 7} are insulating compounds that have an orthorhombic weberite-type crystal structure and undergo a phase transition at about 360 and 450 K, respectively. The nature of the phase transitions was investigated via heat capacity measurements, synchrotron X-ray and neutron diffraction experiments. It is here shown that above the phase transition temperature, the compounds possess a weberite-type structure described by space group Cmcm (No. 63). Below the phase transition, the high temperature phase transforms into a weberite-type structure with space group Pmcn (No. 62). The phase transformation primarily involves the off-center shifting of Nb{sup 5+} ions inside the NbO{sub 6} octahedra, combined with shifts of one third of the Ln{sup 3+} (Ln{sup 3+} = La{sup 3+} and Nd{sup 3+}) ions at the center of the LnO{sub 8} polyhedra towards off-center positions. The phase transition was also proven to have great impacts on the dielectric properties.

Cai, Lu; Nino, Juan C. (ORNL); (Florida)

2011-11-07T23:59:59.000Z

119

Structure of high pressure Ca(OD){sub 2} II from powder neutron diffraction: Relationship to the ZrO{sub 2} and EuI{sub 2} structures  

SciTech Connect (OSTI)

The {open_quotes}unquenchable{close_quotes} high pressure form of Ca(OD){sub 2} [Ca(OH){sub 2}II] has been synthesized at 9 GPa and 400{degrees}C and recovered to ambient pressure at cryogenic temperatures. The structure was determined from powder neutron diffraction data using the Rietveld technique. The symmetry is monoclinic P2{sub 1}/c with a = 5.3979(4) {angstrom}, b = 6.0931(4) {angstrom}, c = 5.9852(4) {angstrom}, {beta} = 103.581(6), Z = 4 at 1 atm and 11 K. R{sub wp} = 2.8%, R{sub p} = 1.9%, reduced {chi}{sup 2} = 6.6. for 117 variables. The calcium and oxygen substructure is intermediate between that in {alpha}-PbO{sub 2} and that in fluorite; it was previously described as isostructural with baddeleyite (ZrO{sub 2}), but it is more accurately described as isostructural with EuI{sub 2}. This structure is distinguished by the presence of a 3{sup 6} anion met parallel to (100). Only one of the two kinds of D atoms in the structure shows appreciable hydrogen bonding to O, with a second neighbor D...O distance of 1.91 {angstrom}, and an O-D...O angle of 153.2{degrees}; the other D atom has 3 second-neighbor oxygens near 2.6 {angstrom} away.

Leinenweber, K.; Partin, D.E.; Schuelke, U. [Arziona State Univ., Tempe, AZ (United States)] [and others] [Arziona State Univ., Tempe, AZ (United States); and others

1997-09-01T23:59:59.000Z

120

JOURNAL DE PHYSIQUE CoZZoque C8, suppZe'ment au n08, Tome 41, aoGt 1980, page C8-156 NEUTRON DIFFRACTION BY LIQUID SEGREGATED COPPER-LEAD ALLOYS  

E-Print Network [OSTI]

38401 Saint Martin drH2res, France. Abstract.- Neutron scattering experiments were performed on liquid corre- .20 is the scattering angle, X the neutron wave- si: 'the modulus of the scatte-lations betweenJOURNAL DE PHYSIQUE CoZZoque C8, suppZe'ment au n08, Tome 41, aoGt 1980, page C8-156 NEUTRON

Boyer, Edmond

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

Secrets of superconductivity revealed  

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

Secrets of superconductivity revealed Secrets of superconductivity revealed Secrets of superconductivity revealed The superconducting material Cerium-Colbalt-Indium5 reveals new secrets about how superconductivity and magnetism can be related. January 3, 2014 Simon Gerber, first author of the publication on the superconducting properties of CeCoIn5 at the Morpheus instrument of the Spallation Neutron Source SINQ in Switzerland. (Photo: Paul Scherrer Institute/Markus Fischer) Simon Gerber, first author of the publication on the superconducting properties of CeCoIn5 at the Morpheus instrument of the Spallation Neutron Source SINQ in Switzerland. (Photo: Paul Scherrer Institute/Markus Fischer) "Superconductivity continues to give new surprises. As its secrets are revealed, we learn more about the quantum world of electrons and can begin

122

Secrets of superconductivity revealed  

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

Secrets of superconductivity revealed Secrets of superconductivity revealed Secrets of superconductivity revealed The superconducting material Cerium-Colbalt-Indium5 reveals new secrets about how superconductivity and magnetism can be related. January 3, 2014 Simon Gerber, first author of the publication on the superconducting properties of CeCoIn5 at the Morpheus instrument of the Spallation Neutron Source SINQ in Switzerland. (Photo: Paul Scherrer Institute/Markus Fischer) Simon Gerber, first author of the publication on the superconducting properties of CeCoIn5 at the Morpheus instrument of the Spallation Neutron Source SINQ in Switzerland. (Photo: Paul Scherrer Institute/Markus Fischer) "Superconductivity continues to give new surprises. As its secrets are revealed, we learn more about the quantum world of electrons and can begin

123

Concepts of Neutron ScatteringConcepts of Neutron Scattering 66thth PSI Summer School on Condensed Matter ResearchPSI Summer School on Condensed Matter Research  

E-Print Network [OSTI]

Concepts of Neutron ScatteringConcepts of Neutron Scattering 66thth PSI Summer School on Condensed Andrew Boothroyd University of Oxford Basic features of neutron scattering Neutron diffraction Neutron on the lattice * * * #12;ScatteringScattering ``nuts and boltsnuts and bolts'' Neutrons, photons, electrons

Boothroyd, Andrew

124

Aqueous Solutions and Neutron Scattering  

Science Journals Connector (OSTI)

The application of neutron diffraction techniques to aqueous solutions is described, and a framework involving the use of isotopic substitution is set up to illustrate the scope of the method. Specific applications described include a study of glassy ...

G. W. Neilson; J. E. Enderby

1996-01-25T23:59:59.000Z

125

Synchrotron and neutron powder diffraction study of phase transition in weberite-type Nd{sub 3}NbO{sub 7} and La{sub 3}NbO{sub 7}  

SciTech Connect (OSTI)

La{sub 3}NbO{sub 7} and Nd{sub 3}NbO{sub 7} are insulating compounds that have an orthorhombic weberite-type crystal structure and undergo a phase transition at about 360 and 450 K, respectively. The nature of the phase transitions was investigated via heat capacity measurements, synchrotron X-ray and neutron diffraction experiments. It is here shown that above the phase transition temperature, the compounds possess a weberite-type structure described by space group Cmcm (No. 63). Below the phase transition, the high temperature phase transforms into a weberite-type structure with space group Pmcn (No. 62). The phase transformation primarily involves the off-center shifting of Nb{sup 5+} ions inside the NbO{sub 6} octahedra, combined with shifts of one third of the Ln{sup 3+} (Ln{sup 3+}=La{sup 3+} and Nd{sup 3+}) ions at the center of the LnO{sub 8} polyhedra towards off-center positions. The phase transition was also proven to have great impacts on the dielectric properties. - Graphical abstract: The phase transition of La{sub 3}NbO{sub 7} and Nd{sub 3}NbO{sub 7} upon cooling primarily involves the off-center shifting of Nb{sup 5+} ions inside the NbO{sub 6} octahedra, combined with shifts of one third of the Ln{sup 3+} (Ln{sup 3+}=La{sup 3+} and Nd{sup 3+}) ions at the center of the LnO{sub 8} polyhedra towards off-center positions. Above the phase transition temperature, Ln{sup 3+} and Nb{sup 5+} sit at a position with mirror symmetry and 2-fold axis. Below the phase transition temperature, Ln{sup 3+} and Nb{sup 5+} shift away from the 2-fold axis but still in the mirror plane. Highlights: > La{sub 3}NbO{sub 7} and Nd{sub 3}NbO{sub 7} exhibit a phase transition at 360 and 450 K, respectively. > The phase transformation primarily involves the off-center shifting of Nb{sup 5+} and Ln{sup 3+}. > The off-center ionic displacement decreases with increasing temperature. > Dielectric properties are greatly related to the off-center displacement.

Cai Lu, E-mail: cail@ornl.gov [Spallation Neutron Source, Oak Ridge National Laboratory, PO Box 2008 MS6454, Oak Ridge, TN 37831 (United States); Nino, Juan C. [Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611 (United States)

2011-08-15T23:59:59.000Z

126

Structural and dynamical studies of superacids and superacidic solutions using neutron and high energy X-ray scattering.  

E-Print Network [OSTI]

?? The diffusive motions of the Brønsted superacid, hydrogen fluoride, have been studied using quasielastic neutron scattering. Neutron and high energy X-ray diffraction measurements on… (more)

Molaison, Jamie John

2006-01-01T23:59:59.000Z

127

Previously, DC Magnets located at Neutron-Scattering Beamlines were commercially-manufactured superconducting magnets and limited to 17 T. A  

E-Print Network [OSTI]

Previously, DC Magnets located at Neutron-Scattering Beamlines were commercially, this was the first designed specifically for neutron scattering and the first to include resistive suitable for neutron scattering, diffraction and spectroscopy experiments with the neutron beam passing

Weston, Ken

128

Combined neutron reflectometry and rheology  

Science Journals Connector (OSTI)

Neutron reflectometry is combined with rheology in order to reveal the near surface structure of liquids and polymers under well defined deformation.

Wolff, M.

2013-10-26T23:59:59.000Z

129

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

130

At Los Alamos's Lujan Neutron Scattering Center, crystallographer...  

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showing off the revealing properties of neutrons February 27, 2014 At Los Alamos's Lujan Neutron Scattering Center, crystallographer Olivier Gourdon shows visiting researchers...

131

Diffraction-Based Density Restraints for Membrane and Membrane-Peptide Molecular Dynamics Simulations  

E-Print Network [OSTI]

or neutron scattering-length density projected along the bilayer normal (5). These profiles represent, California; and z NIST Center for Neutron Research, National Institute of Standards and Technology. INTRODUCTION X-ray and neutron diffraction are commonly used for studying the structure of membrane systems (1

White, Stephen

132

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 ŠLAUS

1967-07-01T23:59:59.000Z

133

Diffractive parton density functions  

E-Print Network [OSTI]

We discuss the perturbative QCD description of diffractive deep-inelastic scattering, and extract diffractive parton distributions from recent HERA data. The asymptotic collinear factorisation theorem has important modifications in the sub-asymptotic HERA regime. In addition to the usual resolved Pomeron contribution, the direct interaction of the Pomeron must also be accounted for. The diffractive parton distributions are shown to satisfy an inhomogeneous evolution equation, analogous to the parton distributions of the photon.

Watt, G

2005-01-01T23:59:59.000Z

134

Diffractive parton density functions  

E-Print Network [OSTI]

We discuss the perturbative QCD description of diffractive deep-inelastic scattering, and extract diffractive parton distributions from recent HERA data. The asymptotic collinear factorisation theorem has important modifications in the sub-asymptotic HERA regime. In addition to the usual resolved Pomeron contribution, the direct interaction of the Pomeron must also be accounted for. The diffractive parton distributions are shown to satisfy an inhomogeneous evolution equation, analogous to the parton distributions of the photon.

G. Watt

2005-11-29T23:59:59.000Z

135

Diffractive deep inelastic scattering  

SciTech Connect (OSTI)

A new approach to the analysis of diffractive deep inelastic data is presented. We show that the collinear factorisation theorem, which holds for diffractive DIS, has important modifications in the sub-asymptotic HERA regime, which can be quantified by using perturbative QCD. In fact the diffractive parton densities are shown to satisfy an inhomogeneous evolution equation. Moreover it is necessary to include both the gluonic and sea-quark t-channel components of the perturbative Pomeron.

Martin, A.D.; Ryskin, M.G. [IPPP, Physics Department, University of Durham, DH1 3LE (United Kingdom); Watt, G. [DESY, 22607 Hamburg (Germany)

2005-10-06T23:59:59.000Z

136

EMSL - Spectroscopy and Diffraction  

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

loss spectroscopy and electron backscatter diffraction Local Electrode Atom Probe tomography system with 355 nm UV laser and reflectron flight path for high mass resolution...

137

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

138

Neutron macromolecular crystallography with LADI-III  

Science Journals Connector (OSTI)

The LADI-III instrument for measuring neutron macromolecular crystallography diffraction data is described. The data collection of type-III perdeuterated antifreeze protein is given as an example.

Blakeley, M.P.

2010-10-20T23:59:59.000Z

139

Neutron and X-ray diffraction studies on the high temperature phase of Mn{sub 3}(VO{sub 4}){sub 2}, the new isostructural compound NaMn{sub 4}(VO{sub 4}){sub 3} and their mixed crystals Na{sub x}Mn{sub 4.5-x/2}(VO{sub 4}){sub 3} (0{<=}x{<=}1)  

SciTech Connect (OSTI)

This paper presents a detailed structure analysis (combined Rietveld analysis of X-ray and neutron powder diffraction data as well as quantum mechanical calculations) of the high temperature phase of Mn{sub 3}(VO{sub 4}){sub 2} (space group I4 Macron 2d). Special attention is directed to the analysis of the local coordination around Mn{sup 2+} ions or vacancies within a stella quadrangula configuration of anions. Furthermore, the new compound NaMn{sub 4}(VO{sub 4}){sub 3} is described as well as a range of mixed crystals between NaMn{sub 4}(VO{sub 4}){sub 3} and Mn{sub 3}(VO{sub 4}){sub 2} (described by the formula Na{sub x}Mn{sub 4.5-x/2}(VO{sub 4}){sub 3}, 0{<=}x{<=}1) which were synthesized by a solid state route. All compounds were shown to be isostructural to the high temperature phase Mn{sub 3}(VO{sub 4}){sub 2}. - Graphical abstract: The crystal structure of the new compound NaMn{sub 4}(VO{sub 4}){sub 3}. Highlights: Black-Right-Pointing-Pointer We present neutron and X-ray diffraction studies on high temperature-Mn{sub 3}(VO{sub 4}){sub 2}. Black-Right-Pointing-Pointer Structural details of partly filled stellae quadrangulae positions are discussed. Black-Right-Pointing-Pointer Refined structural parameters and theoretical calculations are compared. Black-Right-Pointing-Pointer We investigate the mixed crystal system Mn{sub 3}(VO{sub 4}){sub 2}-NaMn{sub 4}(VO{sub 4}){sub 3}.

Clemens, Oliver [Universitaet des Saarlandes, Institut fuer Anorganische und Analytische Chemie und Radiochemie, Am Markt, Zeile 5, 66125 Saarbruecken (Germany)] [Universitaet des Saarlandes, Institut fuer Anorganische und Analytische Chemie und Radiochemie, Am Markt, Zeile 5, 66125 Saarbruecken (Germany); Haberkorn, Robert [Universitaet des Saarlandes, Anorganische Festkoerperchemie, Am Markt, Zeile 3, 66125 Saarbruecken (Germany)] [Universitaet des Saarlandes, Anorganische Festkoerperchemie, Am Markt, Zeile 3, 66125 Saarbruecken (Germany); Springborg, Michael [Universitaet des Saarlandes, Physikalische und Theoretische Chemie, Campus B2 2, 66123 Saarbruecken (Germany)] [Universitaet des Saarlandes, Physikalische und Theoretische Chemie, Campus B2 2, 66123 Saarbruecken (Germany); Beck, Horst Philipp, E-mail: hp.beck@mx.uni-saarland.de [Universitaet des Saarlandes, Institut fuer Anorganische und Analytische Chemie und Radiochemie, Am Markt, Zeile 5, 66125 Saarbruecken (Germany)

2012-10-15T23:59:59.000Z

140

Structure and Dynamics of Cholesterol-Containing Polyunsaturated Lipid Membranes Studied by Neutron  

E-Print Network [OSTI]

Structure and Dynamics of Cholesterol-Containing Polyunsaturated Lipid Membranes Studied by Neutron by neutron diffraction, 2 H-NMR and 13 C-MAS NMR. Scattering length distribution func- tions of cholesterol Phosphatidylcholine Á Membrane Á Cholesterol Á Neutron diffraction Á NMR Introduction The lipid bilayer of cell

White, Stephen

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

Multilayer dielectric diffraction gratings  

DOE Patents [OSTI]

The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described.

Perry, Michael D. (Livermore, CA); Britten, Jerald A. (Oakley, CA); Nguyen, Hoang T. (Livermore, CA); Boyd, Robert (Livermore, CA); Shore, Bruce W. (Livermore, CA)

1999-01-01T23:59:59.000Z

142

Multilayer dielectric diffraction gratings  

DOE Patents [OSTI]

The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described. 7 figs.

Perry, M.D.; Britten, J.A.; Nguyen, H.T.; Boyd, R.; Shore, B.W.

1999-05-25T23:59:59.000Z

143

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

144

Neutrons used to study model vascular systems  

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

(SPEAR) to understand changes in the cell's properties. The technique, which relies on neutron reflectometry to reveal the behavior and composition of the cells, provides a new...

145

EMSL: Capabilities: Spectroscopy and Diffraction  

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

Spectroscopy and Diffraction Spectroscopy and Diffraction Additional Information Meet the Spectroscopy and Diffraction Experts Related EMSL User Projects Spectroscopy and Diffraction Tools are Applied to all Science Themes Tutorial: XPS Tools for Surface Analysis Spectroscopy and Diffraction brochure EMSL's suite of spectroscopy and diffraction instruments allows users to study solid-, liquid-, and gas-phase sample structure and composition with remarkable resolution. Ideal for integrated studies, spectrometers and diffractometers are easily coupled with EMSL's computational and modeling capabilities, allowing users to apply a multifaceted research approach for experimental data interpretation and gain fundamental understanding of scientific problems. At EMSL, spectroscopy and diffraction instruments are

146

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

147

A neutron crystallographic analysis of a rubredoxin mutant at 1.6 ? resolution  

Science Journals Connector (OSTI)

A single-crystal neutron diffraction study has been carried out at 1.6 ? resolution on a mutant rubredoxin from the hyperthermophilic archeon P. furiosus.

Chatake, T.

2004-07-21T23:59:59.000Z

148

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

149

Colored diffraction catastrophes  

Science Journals Connector (OSTI)

...geometrically achromatic. In our bathroom-window glass ex- periments it was easy to achieve this by selecting the central P2C _ U~~~~~~~~~ TX FIG. 7. Arrangement for observing colored diffraction catastro- phes. C, camera; G, glass; L...

M V Berry; S Klein

1996-01-01T23:59:59.000Z

150

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

151

X-ray and neutron diffraction study of the defect crystal structure of the as-grown nonstoichiometric phase Y{sub 0.715}Ca{sub 0.285}F{sub 2.715}  

SciTech Connect (OSTI)

This work begins a series of papers aimed at studying the defect structure of nonstoichiometric phases R{sub 1-y}Ca{sub y}F{sub 3-y} with a tysonite-type (LaF{sub 3}) structure. In the single-crystal structure of Y{sub 0.715}Ca{sub 0.285}F{sub 2.715} with a tysonite-type small unit cell (sp. gr. P6{sub 3}/mmc, a = 3.9095(2) A, c = 6.9829(2) A; Z = 2; R{sub w} = 2.16%), the displacements of Y{sup 3+} cations and F{sup 2-} anions from 6{sub 3} symmetry axes were observed for the first time. The X-ray diffraction pattern shows weak satellites insufficient for structural calculations. The LaF{sub 3} structure type is stabilized up and down on the temperature scale due to anion vacancies and the symmetrizing effect of Ca{sup 2+} cations lying on 6{sub 3} symmetry axes. At 120 Degree-Sign C the fluoride-ion conductivity in the nonstoichiometric phase Y{sub 0.715}Ca{sub 0.285}F{sub 2.715} is five orders of magnitude higher than that in the stoichiometric phase {beta}-YF{sub 3}. The transition to a superionic state is caused by a deviation from stoichiometry and is not associated with reconstructive phase transformation.

Bolotina, N. B., E-mail: bolotina@ns.crys.ras.ru; Kalyukanov, A. I.; Chernaya, T. S.; Verin, I. A.; Buchinskaya, I. I.; Sorokin, N. I.; Sobolev, B. P. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2013-07-15T23:59:59.000Z

152

Magnetic measurements and neutron diffraction study of the layered hybrid compounds Mn(C{sub 8}H{sub 4}O{sub 4})(H{sub 2}O){sub 2} and Mn{sub 2}(OH){sub 2}(C{sub 8}H{sub 4}O{sub 4})  

SciTech Connect (OSTI)

Mn(C{sub 8}H{sub 4}O{sub 4})(H{sub 2}O){sub 2} and Mn{sub 2}(OH){sub 2}(C{sub 8}H{sub 4}O{sub 4}) layered organic-inorganic compounds based on manganese(II) and terephthalate molecules (C{sub 8}H{sub 4}O{sub 4}{sup 2-}) have been studied by DC and AC magnetic measurements and powder neutron diffraction. The dihydrated compound behaves as a 3D antiferromagnet below 6.5 K. The temperature dependence of its {chi}T product is typical of a 2D Heisenberg system and allows determining the in-plane exchange constant J Almost-Equal-To -7.4 K through the carboxylate bridges. The magnetic structure confirms the in-plane nearest neighbor antiferromagnetic interactions and the 3D ordering. The hydroxide based compound also orders as a 3D antiferromagnet with a higher Neel temperature (38.5 K). Its magnetic structure is described from two antiferromagnetically coupled ferromagnetic sublattices, in relation with the two independent metallic sites. The isothermal magnetization data at 2 K are consistent with the antiferromagnetic ground-state of these compounds. However, in both cases, a slope change points to field-induced modification of the magnetic structure. - Graphical abstract: The macroscopic magnetic properties and magnetic structures of two metal-organic frameworks based on manganese (II) and terephthalate molecules are presented. Highlights: Black-Right-Pointing-Pointer Magnetic study of Mn(C{sub 8}H{sub 4}O{sub 4})(H{sub 2}O){sub 2} and Mn{sub 2}(OH){sub 2}(C{sub 8}H{sub 4}O{sub 4}). Black-Right-Pointing-Pointer Two compounds with common features (interlayer linker/distance, S=5/2 spin). Black-Right-Pointing-Pointer Magnetic measurements quantitatively analyzed to deduce exchange constants. Black-Right-Pointing-Pointer Magnetic structures determined from neutron powder diffraction experiments.

Sibille, Romain, E-mail: romain.sibille@ijl.nancy-universite.fr [Institut Jean Lamour, UMR 7198-Nancy Universite, BP 70239, 54506 Vandoeuvre-les-Nancy Cedex (France); Mesbah, Adel; Mazet, Thomas; Malaman, Bernard [Institut Jean Lamour, UMR 7198-Nancy Universite, BP 70239, 54506 Vandoeuvre-les-Nancy Cedex (France); Capelli, Silvia [Institut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Francois, Michel [Institut Jean Lamour, UMR 7198-Nancy Universite, BP 70239, 54506 Vandoeuvre-les-Nancy Cedex (France)

2012-02-15T23:59:59.000Z

153

Soft X-Ray Diffraction Microscopy of a Frozen Hydrated Yeast Cell Xiaojing Huang,1  

E-Print Network [OSTI]

Soft X-Ray Diffraction Microscopy of a Frozen Hydrated Yeast Cell Xiaojing Huang,1 Johanna Nelson,1 eukaryotic cell using x-ray diffraction microscopy, or coherent x-ray diffraction imaging. By plunge freezingV x rays were recorded and reconstructed to reveal a budding yeast cell at a resolution better than 25

Mohseni, Hooman

154

Neutron scattering, a powerful tool to study clay minerals  

Science Journals Connector (OSTI)

Abstract Of the techniques used to study clay minerals, neutron scattering has become more familiar to clay scientists over the past decade. A brief account of neutron scattering theory is given in this review, followed by a description of measurements that can be made using neutron diffraction and neutron scattering spectroscopy, and especially quasi-elastic neutron scattering. Then recent examples of the application of neutron scattering methods to the study of clay minerals are presented, and finally the potential advantages of such experimental results when combined to molecular dynamics are discussed. To conclude, the potential perspectives that the European Spallation Source brings to this subject are pointed out.

Murillo L. Martins; Will P. Gates; Laurent Michot; Eric Ferrage; Virginie Marry; Heloisa N. Bordallo

2014-01-01T23:59:59.000Z

155

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

156

POWDER: The Neutron Powder Diffractometer at HFIR | ORNL Neutron Sciences  

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

Neutron Powder Diffractometer Neutron Powder Diffractometer Neutron Powder Diffractometer. Neutron Powder Diffractometer. The HB-2A diffractometer is a workhorse instrument used to conduct crystal structural and magnetic structural studies of powdered and ceramic samples, particularly as a function of intensive conditions (T, P, H, etc.). Powder diffraction data collected on this instrument are ideally suited for the Rietveld method. A full range of ancillary sample environments can be used, including cryofurnaces (4-800 K), furnaces (to 1800 K), cryostats (to 0.3 K), and cryomagnets (to 7 T). The Powder Diffractometer has a Debye-Scherrer geometry. The detector bank has 44 3He tubes, each with 6' Soller collimators. A germanium wafer-stack monochromator is vertically focusing and provides one of three principal

157

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

158

Awards 2007 | ORNL Neutron Sciences  

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

7 7 Staff Awards: 2007 Chakoumakos elected MSA Fellow Bryan Chakoumakos Neutron scientist Bryan Chakoumakos was recently elected a fellow of the Mineralogical Society of America. A member of the Neutron Scattering Science Division, Bryan leads the Single-Crystal Diffraction Group. The group has five neutron scattering instruments in various stages of design and construction, located at HFIR and SNS. The MSA was founded in 1919 and, among other goals, encourages fundamental research on natural materials and supports education through its publications, educational grants, and courses. Pharos Neutron Detector System Researchers at the Department of Energy's Oak Ridge National Laboratory have won six R&D 100 Awards, given annually by R&D Magazine to the year's

159

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

160

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

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

The first X-ray diffraction measurements on Mars  

Science Journals Connector (OSTI)

The X-ray diffraction/X-ray fluorescence instrument CheMin on the Curiosity rover is a shoebox-sized device using transmission geometry and an energy-discriminating CCD detector. The instrument has returned the first X-ray diffraction data for soil and drilled samples from Mars outcrops, revealing a suite of primary basaltic minerals, amorphous components and varied hydrous alteration products including phyllosilicates.

Bish, D.

2014-10-21T23:59:59.000Z

162

Protein crystallography with spallation neutrons  

SciTech Connect (OSTI)

proteins and oriented molecular complexes. With spallation neutrons and their time dependent wavelength structure, one can select data with an optimal wavelength bandwidth and cover the whole Laue spectrum as time (wavelength) resolved diffraction data. This optimizes data quality with best peak to background ratios and provides spatial and energy resolution to eliminate peak overlaps. Such a Protein Crystallography Station (PCS) has been built and tested at Los Alamos Neutron Science Center. A partially coupled moderator is used to increase flux and data are collected by a Cylindrical He3 detector covering 120' with 200mm height. The PCS is described along with examples of data collected from a number of proteins.

Langan, P. (Paul); Schoenborn, Benno P.

2003-01-01T23:59:59.000Z

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

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...

165

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

166

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

167

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

168

NEUTRON SCATTERING SHOWS THAT CYTOCHROME b5 PENETRATES DEEPLY INTO THE LIPID BILAYER  

E-Print Network [OSTI]

NEUTRON SCATTERING SHOWS THAT CYTOCHROME b5 PENETRATES DEEPLY INTO THE LIPID BILAYER E. P. GOGOL to lipid vesicles using neutron small-angle scattering methods. To increase scat- tering contrast between of a highly deuterated phospholipid. Small-angle neutron diffraction patterns were collected in a series of H

169

Oxides: neutron and synchrotron X-ray diffraction studies  

Science Journals Connector (OSTI)

......the opal silica-water system. Keywords...oxides, opal silica-water system Received 11...order to perform advanced structure studies...oxides containing water (superionic non-stoichiometric...presence of very heavy atoms and to distin...using the IBR pulsed reactor in structure analysis......

Izabela M. Sosnowska; Makoto Shiojiri

1999-01-01T23:59:59.000Z

170

Neutron Powder Diffraction and Molecular Simulation Study of...  

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

leading to the rotation of the B-N bond parallel to the c-axis. The structural phase transition at 225 K is marked by dramatic change in the dynamics of both the amine and borane...

171

Cryogenic Neutron Protein Crystallography: routine methods and potential benefits  

SciTech Connect (OSTI)

The use of cryocooling in neutron diffraction has been hampered by several technical challenges such as the need for specialized equipment and techniques. Recently we have developed and deployed equipment and strategies that allow for routine neutron data collection on cryocooled crystals using off the shelf components. This system has several advantages, compared to a closed displex cooling system such as fast cooling coupled with easier crystal mounting and centering. The ability to routinely collect cryogenic neutron data for analysis will significantly broaden the range of scientific questions that can be examined by neutron protein crystallography. Cryogenic neutron data collection for macromolecules has recently become available at the new Biological Diffractometer BIODIFF at FRM II and the Macromolecular Diffractometer (MaNDi) at the Spallation Neutron Source, Oak Ridge National Laboratory. To evaluate the benefits of a cryocooled neutron structure we collected a full neutron data set on the BIODIFF instrument on a Toho-1 lactamase structure at 100K.

Weiss, Kevin L [ORNL; Tomanicek, Stephen J [ORNL; NG, Joseph D [ORNL

2014-01-01T23:59:59.000Z

172

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. Gähler; A. Steyerl; W. Mampe

1985-05-06T23:59:59.000Z

173

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

174

Diffraction dissociation at the LHC  

SciTech Connect (OSTI)

We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

Jenkovszky, Laszlo [Bogolyubov Institute for Theoretical Physics (BITP), Ukrainian National Academy of Sciences 14-b, Metrolohichna str., Kiev, 03680, Ukraine and Wigner Research Centre for Physics, Hungarian Academy of Sciences 1525 Budapest, POB 49 (Hungary); Orava, Risto [Institute of Physics, Division of Elementary Particle Physics, P.O. Box 64 (Gustaf Haellstroeminkatu 2a), FI-00014 University of Helsinki, Finland and CERN, CH-1211 Geneva 23 (Switzerland); Salii, Andrii [Bogolyubov Institute for Theoretical Physics (BITP), Ukrainian National Academy of Sciences 14-b, Metrolohichna str., Kiev, 03680 (Ukraine)

2013-04-15T23:59:59.000Z

175

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

176

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

177

Neutrons used to study model vascular January 22, 2014  

E-Print Network [OSTI]

) to understand changes in the cell's properties. The technique, which relies on neutron reflectometry to reveal under physiologic shear stress conditions. The strength of neutron reflectometry is its non The team made neutron reflectometry measurements at 25 o C and 37 o C (physiologic temperature

178

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

179

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; Frédéric Ott; Alain Menelle

1999-01-01T23:59:59.000Z

180

Boron neutron capture enhancement of fast neutron radiotherapy  

Science Journals Connector (OSTI)

Clinical trials have revealed a therapeutic advantage for fast neutron radiation over conventional photon radiation for salivary gland cancer prostate cancer sarcoma and a subgroup of lung cancer. Conversely fast neutron treatment of high grade astrocytic brain tumors [glioblastoma multiforme (GBM)] resulted in tumor sterilization but also caused significant brain injury such that no therapeutic gain was attained. This effect was important however in that photon radiation and other conventional treatments have not demonstrated sterilization of GBM at any dose. Recent laboratory studies demonstrated that the hospital-based fast neutron beam from the University of Washington cyclotron has a thermal neutron component that may be used in a boron-10 neutron capture (BNC) reaction to enhance cell kill. The degree of enhancement was approximately 10 fold and was dependent upon the boron-10 concentration the boron-10 carrier agent and the fast neutron dose per fraction. The results of these experiments will be discussed in the context of creating a therapeutic window for treatment of glioblastoma using BNC-enhanced fast neutron radiation in a clinically tolerable regimen.

K. J. Stelzer; G. E. Laramore; R. Risler; L. Wiens; T. W. Griffin

1997-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

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

182

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

183

Neutron scattering techniques as a tool for nondestructive testing  

Science Journals Connector (OSTI)

Neutron scattering techniques such as neutron diffraction, Small-Angle Neutron Scattering (SANS) and Neutron Reflectivity (NREF) are very powerful tools for the nondestructive study of materials. The corresponding experimental facilities at a Greek research reactor and demonstrative experiments of their employment in the nondestructive testing of materials are presented. Neutron diffraction was applied in the study of irradiation effects on SiCf /SiC composites in view of their application to future fusion reactors. SiC materials are important in the aerospace industry and their oxidation at high temperatures was investigated by NREF. Finally, a SANS study of the precipitation of the aerospace Al-8.9at%Li alloy is presented.

G. Apostolopoulos; K. Mergia; A.G. Youtsos

2009-01-01T23:59:59.000Z

184

Detonation Diffraction into a Confined Volume.  

E-Print Network [OSTI]

??Detonation diffraction has been, and remains, an active area of research. However, detonation diffraction into a confined volume, and specifically the transformation of a planar… (more)

Polley, Nolan Lee

2012-01-01T23:59:59.000Z

185

Neutron scattering investigation of the magnetic order in single crystalline BaFe2As2  

SciTech Connect (OSTI)

The magnetic structure of BaFe{sub 2}As{sub 2} was determined from polycrystalline neutron diffraction measurements soon after the ThCr{sub 2}Si{sub 2}-type FeAs-based superconductors were discovered. Both the moment direction and the in-plane antiferromagnetic wavevector are along the longer a-axis of the orthorhombic unit cell. There is only one combined magnetostructural transition at {approx}140 K. However, a later single-crystal neutron diffraction work reported contradicting results. Here, we show neutron diffraction results from a single-crystal sample, grown by a self-flux method, that support the original polycrystalline work.

Bao, Wei [Los Alamos National Laboratory; Qiu, Y [NIST; Kofu, M [UNIV OF VA; Lee, S - H [UNIV OF VA; Chang, S [NIST; Wu, T [HEFEI NAT. LAB.; Wu, G [HEFEI NAT. LAB; Chen, X H [HEFEI NAT. LAB

2008-01-01T23:59:59.000Z

186

The suppression of fluorescence peaks in energy-dispersive X-ray diffraction  

Science Journals Connector (OSTI)

It is shown experimentally that diffraction peaks which are normally obscured by fluorescence peaks in energy-dispersive X-ray diffraction can be revealed by tuning of the X-ray tube excitation voltage in order to suppress the fluorescence peaks.

Hansford, G.M.

2014-09-30T23:59:59.000Z

187

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

188

MULTI-SCALE DIFFRACTION STUDY OF REVERSIBLE/IRREVERSIBLE DEFORMATION MECHANISMS IN THE NI-BASED SUPERALLOYS DURING FATIGUE  

SciTech Connect (OSTI)

In this study, a nickel-based polycrystalline is subjected to cyclic loading. The subsequent fatigue damage has been investigated with in-situ neutron-diffraction, thermal characterization for a single-phase, transmission-electron microscopy (TEM) and polychromatic X-ray microdiffraction (PXM). Different stages of fatigue damage are observed including bulk hardening, softening, and eventual saturation evident in the diffraction patterns and the thermal-evolution features. An increase in dislocation density is responsible for hardening within the early cycles. The transition to saturation cycles is characterized by the anisotropy of the lattice-strain evolution. Inhomogeneity of the thermal response and irreversible compression of the lattice planes and statistical dislocation structures are observed in the final saturation fatigue cycles. Analysis of the PXM-Laue patterns reveals cyclically-deformed microstructure near the grain boundaries, which are composed of the lattice rotations and grain subdivisions. The PXM results are in good agreement with the TEM results. Combined simulation/experimental analysis allows determination of slip-system dependent dislocation density in individual grains.

Barabash, Rozaliya [ORNL; Huang, E-Wen [ORNL; Clausen, Bjorn [ORNL; Liu, W. [Argonne National Laboratory (ANL); Ice, Gene E [ORNL; Liaw, Peter K [University of Tennessee, Knoxville (UTK)

2010-01-01T23:59:59.000Z

189

Borman effect in resonant diffraction of X-rays  

SciTech Connect (OSTI)

A dynamic theory of resonant diffraction (occurring when the energy of incident radiation is close to the energy of the absorption edge of an element in the composition of a given substance) of synchronous X-rays is developed in the two-wave approximation in the coplanar Laue geometry for large grazing angles in perfect crystals. A sharp decrease in the absorption coefficient in the substance with simultaneously satisfied diffraction conditions (Borman effect) is demonstrated, and the theoretical and first experimental results are compared. The calculations reveal the possibility of applying this approach in analyzing the quadrupole-quadrupole contribution to the absorption coefficient.

Oreshko, A. P., E-mail: ap.oreshko@physics.msu.ru [Moscow State University (Russian Federation)

2013-08-15T23:59:59.000Z

190

Models to analyze small-angle neutron scattering from unilamellar lipid vesicles Norbert Kucerka* and John F. Nagle  

E-Print Network [OSTI]

Models to analyze small-angle neutron scattering from unilamellar lipid vesicles Norbert Kucerka from small-angle neutron scattering of unilamellar vesicles. DOI: 10.1103/PhysRevE.69.051903 PACS discrete diffraction peaks that occur for multilamellar arrays, the scattering of x rays or neutrons from

Nagle, John F.

191

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

192

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

193

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...

194

A QCD analysis of ZEUS diffractive data  

E-Print Network [OSTI]

ZEUS inclusive diffractive cross-section measurements have been used in a DGLAP next-to-leading-order QCD analysis to extract the diffractive parton distribution functions. Data on diffractive dijet production in deep inelastic scattering have also been included to costrain the gluon density. Predictions based on the extracted parton densities are compared to diffractive charm and dijet photoproduction data.

ZEUS Collaboration

2009-11-23T23:59:59.000Z

195

Diffraction encoded position measuring apparatus  

DOE Patents [OSTI]

When a lightwave passes through a transmission grating, diffracted beams appear at the output or opposite side of the grating that are effectively Doppler shifted in frequency (phase) whereby a detector system can compare the phase of the zero order and higher order beams to obtain an indication of position. Multiple passes through the grating increase resolution for a given wavelength of a laser signal. The resolution can be improved further by using a smaller wavelength laser to generate the grating itself. Since the grating must only have a pitch sufficient to produce diffracted orders, inexpensive, ultraviolet wavelength lasers can be utilized and still obtain high resolution detection.

Tansey, Richard J. (Thousand Oaks, CA)

1991-01-01T23:59:59.000Z

196

Diffraction encoded position measuring apparatus  

DOE Patents [OSTI]

When a lightwave passes through a transmission grating, diffracted beams appear at the output or opposite side of the grating that are effectively Doppler shifted in frequency (phase) whereby a detector system can compare the phase of the zero order and higher order beams to obtain an indication of position. Multiple passes through the grating increase resolution for a given wavelength of a laser signal. The resolution can be improved further by using a smaller wavelength laser to generate the grating itself. Since the grating must only have a pitch sufficient to produce diffracted orders, inexpensive, ultraviolet wavelength lasers can be utilized and still obtain high resolution detection. 3 figures.

Tansey, R.J.

1991-09-24T23:59:59.000Z

197

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 (2.35±0.1)×10-24 cm2 in agreement with previous investigations. It is shown that the larger value of 3.15×10-24 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

198

WAND: Wide-Angle Neutron Diffractometer at HFIR | ORNL Neutron Sciences  

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

US/Japan Wide-Angle Neutron Diffractometer US/Japan Wide-Angle Neutron Diffractometer WAND Instrument scientist Jaime Fernandez-Baca (left) with a visiting researcher at WAND. The Wide-Angle Neutron Diffractometer (WAND) at the HFIR HB-2C beam tube was designed to provide two specialized data-collection capabilities: (1) fast measurements of medium-resolution powder-diffraction patterns and (2) measurements of diffuse scattering in single crystals using flat-cone geometry. For these purposes, this instrument is equipped with a curved, one-dimensional 3He position-sensitive detector covering 125º of the scattering angle with the focal distance of 71 cm. The sample and detector can be tilted in the flat-cone geometry mode. These features enable measurement of single-crystal diffraction patterns in a short time over a

199

Neutron scattering from myelin revisited: bilayer asymmetry and water-exchange kinetics  

Science Journals Connector (OSTI)

The structure of internodal myelin in the rodent central and peripheral nervous systems has been determined using neutron diffraction. The kinetics of water exchange in these tissues is also described.

Denninger, A.R.

2014-11-22T23:59:59.000Z

200

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 diffraction reveals" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

NEUTRON 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

202

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

203

Research Highlights | ORNL Neutron Sciences  

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

Biology & Medicine Archive Biology & Medicine Archive Research Highlights Biology & Medicine Archive Small-Angle Neutron Scattering Team Finds Structural Differences in Sindbis Virus Particles from Different Host Species (2010) Published Work: "The Structure of Sindbis Virus Produced from Vertebrate and Invertebrate Hosts as Determined by Small-Angle Neutron Scattering" Contact: Flora Meilleur Targeted Drug Delivery Systems Studies of the unique structure of synthetic molecules will help in the development of drugs that can target diseased areas of the body. This researched on dendrimers revealed how molecules function within solutions at different pH levels. (2008) Research in progress. Contact: Wei-Ren Chen "Intelligent" Polymers for Biomedical Technologies

204

Slow Neutron Scattering by the Titanium Isotopes  

Science Journals Connector (OSTI)

Neutron diffraction studies are reported on isotopically enriched samples of TiO2 from which are evaluated the coherent scattering amplitudes of the titanium isotopes. Scattering amplitudes of +0.48, +0.33, -0.58, +0.08, and +0.55×10-12 cm were established for the titanium isotopes of mass 46, 47, 48, 49, and 50, respectively. The major isotope Ti48 is thus responsible for the anomalous scattering amplitude, -0.34×10-12 cm, characteristic of the normal element. Pronounced nuclear scattering resonance effects on the observed neutron scattering are suggested to occur for most of the isotopes.

C. G. Shull; M. K. Wilkinson; M. H. Mueller

1960-05-01T23:59:59.000Z

205

Neutron scattering studies of carbon nanotubes  

Science Journals Connector (OSTI)

We report on neutron scattering studies of single wall carbon nanotubes (SWNT). Small angle scattering was used to investigate the structure of SWNT suspensions. Diffraction data were compared to calculations on finite-size bundles of SWNT in order to estimate the distribution of tube diameters. Lastly we present an inelastic neutron scattering study of the density of phonon states in SWNT. In the frequency range of intramolecular modes the measured spectrum is found to be in good agreement with that calculated on an isolated (10 10) nanotube.

E. Anglaret; S. Rols; J. L. Sauvajol

1999-01-01T23:59:59.000Z

206

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

207

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

208

Neutron Scattering Investigation of Phonon Scattering Rates in Ag1-xSb1+xTe2+x (x = 0, 0.1, and 0.2)  

SciTech Connect (OSTI)

The phonon dispersions and scattering rates of the thermoelectric material AgSbTe$_{2}$ were measured as a function of temperature with inelastic neutron scattering. The results show that phonon scattering rates are large and weakly dependent on temperature. The lattice thermal conductivity was calculated from the measured phonon lifetimes and group velocities, providing good agreement with bulk transport measurements. The measured phonon scattering rates and their temperature dependence are compared with models of phonon scattering by anharmonicity and point defect. We find that these processes cannot account for the large total phonon scattering rates observed, and their lack of temperature dependence. Neutron and synchrotron diffraction measurements on single crystals revealed an extensive nanostructure from cation ordering, which is likely responsible for the strong phonon scattering.

Abernathy, Douglas L [ORNL; Budai, John D [ORNL; Delaire, Olivier A [ORNL; Ehlers, Georg [ORNL; Hong, Tao [ORNL; Karapetrova, Evguenia A. [Argonne National Laboratory (ANL); Ma, Jie [ORNL; May, Andrew F [ORNL; McGuire, Michael A [ORNL; Specht, Eliot D [ORNL

2014-01-01T23:59:59.000Z

209

Neutron Diffraction Performance Based on Multiple Reflection Monochromator for High-Resolution Neutron Radiography  

Science Journals Connector (OSTI)

The effects of multiple Bragg reflections in single crystal can be observed when more than one set of planes are simultaneously operative for a given wavelength i.e. when more than two reciprocal lattice point...

Pavel Mikula; Miroslav Vrana

2007-01-01T23:59:59.000Z

210

Colossal Light-Induced Refractive-Index Modulation for Neutrons in Holographic Polymer-Dispersed Liquid Crystals  

SciTech Connect (OSTI)

We report strong diffraction of cold neutrons from an only 30 {mu}m thick holographic polymer-dispersed liquid crystal (H-PDLC) transmission grating. The light-induced refractive-index modulation for neutrons is about 10{sup -6}, i.e., nearly 2 orders of magnitude larger than in the best photo-neutron-refractive materials probed up to now. This makes H-PDLCs a promising candidate for fabricating neutron-optical devices.

Fally, Martin; Ellabban, Mostafa A. [Nonlinear Physics Group, Faculty of Physics, Universitaet Wien, Boltzmanngasse 5, A-1090 Vienna (Austria); Drevensek-Olenik, Irena [Nonlinear Physics Group, Faculty of Physics, Universitaet Wien, Boltzmanngasse 5, A-1090 Vienna (Austria); Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, and J. Stefan Institute, Jamova 39, SI 1001 Ljubljana (Slovenia); Pranzas, Klaus P.; Vollbrandt, Juergen [GKSS Forschungszentrum, D-21502 Geesthacht (Germany)

2006-10-20T23:59:59.000Z

211

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

212

Research Highlights | ORNL Neutron Sciences  

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

Atomic-Scale Behavior of "Cobalt Blue" Atomic-Scale Behavior of "Cobalt Blue" Neutron Analysis Reveals Unique Atomic-Scale Behavior of "Cobalt Blue" Research Contact: Gregory MacDougall ORNL News Release, September 2011, Media Contact: Bill Cabage Cobalt aluminate Just as cobalt blue's lustrous hue attracts artists and decorators, the antiferromagnetic properties of the responsible compound-cobalt aluminate-are attracting neutron scientists at DOE's Oak Ridge National Laboratory. Studies of magnetic interactions deep within the material's atomic structure may provide clues toward the development of energy-efficient technologies. (Light sconce image courtesy of B. Jefferson Bolender. Click image for high res version.) Neutron scattering studies of "cobalt blue," a compound prized by artists

213

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

214

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

215

Detonation Diffraction into a Confined Volume  

E-Print Network [OSTI]

Detonation diffraction has been, and remains, an active area of research. However, detonation diffraction into a confined volume, and specifically the transformation of a planar detonation into a cylindrical detonation, is an area which has received...

Polley, Nolan Lee

2012-02-14T23:59:59.000Z

216

A Model Graphene Diffraction Pattern Frank Rioux  

E-Print Network [OSTI]

A Model Graphene Diffraction Pattern Frank Rioux The purpose of this tutorial is to model graphene d Pj k px j py k 2 i 1 A Graphene Model Diffraction Pattern #12;

Rioux, Frank

217

Diffractive dijet and W production in CDF  

SciTech Connect (OSTI)

Results on diffractive dijet and W-boson production from CDF are reviewed and compared with predictions based on factorization of the diffractive structure function of the proton measured in deep inelastic scattering at HERA.

Goulianos, K. [Rockefeller Univ., New York, NY (United States)

1998-06-01T23:59:59.000Z

218

Nuclear dynamical diffraction using synchrotron radiation  

SciTech Connect (OSTI)

The scattering of synchrotron radiation by nuclei is extensively explored in this thesis. From the multipole electric field expansion resulting from time-dependent nonrelativistic perturbation theory, a dynamical scattering theory is constructed. This theory is shown, in the many particle limit, to be equivalent to the semi-classical approach where a quantum mechanical scattering amplitude is used in the Maxwell inhomogeneous wave equation. The Moessbauer specimen whose low-lying energy levels were probed is a ferromagnetic lattice of {sup 57}Fe embedded in a yttrium iron garnet (YIG) crystal matrix. The hyperfine fields in YIG thin films were studied at low and room temperature using time-resolved quantum beat spectroscopy. Nuclear hyperfine structure quantum beats were measured using a fast plastic scintillator coincidence photodetector and associated electronics having a time resolution of 2.5 nsec. The variation of the quantum beat patterns near the Bragg [0 0 2] diffraction peak gave a Lamb-Moessbauer factor of 8.2{plus_minus}0.4. Exploring characteristic dynamical features in the higher order YIG [0 0 10] reflection revealed that one of the YIG crystals had bifurcated into two different layers. The dynamics of nuclear superradiance was explored. This phenomenon includes the radiative speedup exhibited by a collective state of particles, and, in striking concurrence, resonance frequency shifts. A speedup of a factor of 4 in the total decay rate and a beat frequency shift of 1{1/2} natural resonance linewidths were observed. Nuclear resonance scattering was also found to be a useful way of performing angular interferometry experiments, and it was used to observe the phase shift of a rotated quantum state. On the whole, nuclear dynamical diffraction theory has superbly explained many of the fascinating features of resonant magnetic dipole radiation scattered by a lattice of nuclei.

Brown, D.E.

1993-05-01T23:59:59.000Z

219

Scalar Diffraction in Terms of Coherence  

Science Journals Connector (OSTI)

...research-article Scalar Diffraction in Terms of Coherence W. H. Steel In scalar diffraction theory...correlation function, here called the 'coherence', rather than in quantities such as...diffraction is developed here based on the coherence between radiation at pairs of points...

1959-01-01T23:59:59.000Z

220

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...

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

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

222

Calculations of neutron spectra after neutron–neutron scattering  

Science Journals Connector (OSTI)

A direct neutron–neutron 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 proton–proton 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 spectrum—Maxwellian plus epithermal tail. The shape of the neutron spectrum after scattering is appreciably different from the initial spectrum, due to collisions between thermal–thermal and thermal–epithermal 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

223

Dr. Michael Agamalian | ORNL Neutron Sciences  

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

Dr. Michael Agamalian Dr. Michael Agamalian Lead Scientist, Ultra-Small-Angle Neutron Scattering (USANS), SNS Education PhD in Physics, St. Petersburg Nuclear Physics Institute, Russia Description of Research Michael Agamalian and collaborators have made important contributions to the development of the ORNL Bonse-Hart Ultra-Small-Angle Neutron Scattering instrument (USANS). In particular, they adopted the classical X-ray Bonse-Hart technique for neutrons by modifying the Si channel-cut crystal and introducing an additional element, a Cd absorber. This innovation, combined with application of a specialized chemical-mechanical treatment of the diffractive surfaces of the Si channel-cut crystal, has increased the sensitivity of the ORNL USANS instrument by three orders of magnitude. This

224

Chemical and Engineering Materials | Neutron Science | ORNL  

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

Chemical and Engineering Materials Chemical and Engineering Materials SHARE Chemical and Engineering Materials Neutron-based research at SNS and HFIR in Chemical and Engineering Materials strives to understand the structure and dynamics of chemical systems and novel engineering materials. The user community takes advantage of capabilities of neutron scattering for measurements over wide ranges of experimental and operating conditions, including studies of chemical and physical changes in situ. User experiments with diffraction, small-angle scattering, inelastic and quasi-elastic scattering, and neutron imaging instruments address a range of problems in chemistry and in engineering materials research. Current areas of research supported within Chemical and Engineering Materials include: The structure and dynamics of electrical energy storage materials

225

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...

226

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 ??=887.6±3 s.

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

1989-08-07T23:59:59.000Z

227

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

228

Energy Density Functional for Nuclei and Neutron Stars  

SciTech Connect (OSTI)

Background: Recent observational data on neutron star masses and radii provide stringent constraints on the equation of state of neutron rich matter [ Annu. Rev. Nucl. Part. Sci. 62 485 (2012)]. Purpose: We aim to develop a nuclear energy density functional that can be simultaneously applied to finite nuclei and neutron stars. Methods: We use the self-consistent nuclear density functional theory (DFT) with Skyrme energy density functionals and covariance analysis to assess correlations between observables for finite nuclei and neutron stars. In a first step two energy functionals a high density energy functional giving reasonable neutron properties, and a low density functional fitted to nuclear properties are matched. In a second step, we optimize a new functional using exactly the same protocol as in earlier studies pertaining to nuclei but now including neutron star data. This allows direct comparisons of performance of the new functional relative to the standard one. Results: The new functional TOV-min yields results for nuclear bulk properties (energy, rms radius, diffraction radius, and surface thickness) that are of the same quality as those obtained with the established Skyrme functionals, including SV-min. When comparing SV-min and TOV-min, isoscalar nuclear matter indicators vary slightly while isovector properties are changed considerably. We discuss neutron skins, dipole polarizability, separation energies of the heaviest elements, and proton and neutron drip lines. We confirm a correlation between the neutron skin of 208Pb and the neutron star radius. Conclusions: We demonstrate that standard energy density functionals optimized to nuclear data do not carry information on the expected maximum neutron star mass, and that predictions can only be made within an extremely broad uncertainty band. For atomic nuclei, the new functional TOV-min performs at least as well as the standard nuclear functionals, but it also reproduces expected neutron star data within assumed error bands. This functional is expected to yield more reliable predictions in the region of very neutron rich heavy nuclei.

Erler, J. [UTK/ORNL/German Cancer Research Center-Heidelberg; Horowitz, C. J. [UTK/ORNL/Indiana University; Nazarewicz, Witold [UTK/ORNL/University of Warsaw; Rafalski, M. [UTK/ORNL; Reinhard, P.-G. [Universitat Erlangen, Germany

2013-01-01T23:59:59.000Z

229

Neutrons Reveal New Electrocatalyst Family for Producing Hydrogen...  

Office of Science (SC) Website

systems currently in use. Summary Most renewable energy is produced in the form of electricity, which is expensive to store and transport in large quantities. Producing hydrogen...

230

Soft X-Ray Diffraction Microscopy of a Frozen Hydrated Yeast Cell  

SciTech Connect (OSTI)

We report the first image of an intact, frozen hydrated eukaryotic cell using x-ray diffraction microscopy, or coherent x-ray diffraction imaging. By plunge freezing the specimen in liquid ethane and maintaining it below -170 deg. C, artifacts due to dehydration, ice crystallization, and radiation damage are greatly reduced. In this example, coherent diffraction data using 520 eV x rays were recorded and reconstructed to reveal a budding yeast cell at a resolution better than 25 nm. This demonstration represents an important step towards high resolution imaging of cells in their natural, hydrated state, without limitations imposed by x-ray optics.

Huang Xiaojing; Nelson, Johanna; Lima, Enju; Miao, Huijie; Steinbrener, Jan; Stewart, Andrew; Turner, Joshua J.; Jacobsen, Chris [Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800 (United States); Kirz, Janos [Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800 (United States); Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Marchesini, Stefano; Shapiro, David [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Neiman, Aaron M. [Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794-5215 (United States)

2009-11-06T23:59:59.000Z

231

Characterization of Ni/Al multilayer on Si substrate by diffraction and reflectometry techniques  

SciTech Connect (OSTI)

An ion beam deposited multilayer film of nominal thickness [Ni(200 Angst )/Al(100 Angst )]x5 on Si substrate has been characterized by X-Ray Diffraction(XRD), X-Ray Reflectivity (XRR) and Polarized neutron reflectivity(PNR). The present paper attempts to identify presence of any intermetallic compounds at the interfaces of the as-deposited sample. Structural parameters obtained from XRR and PNR are close to design values.

Swain, Mitali; Basu, Saibal; Bhattacharya, Debarati; Gupta, Mukul [Solid State Physics Division Bhabha Atomic Research Center, Mumbai 400085 (India); UGC-DAE-Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452017 (India)

2012-06-05T23:59:59.000Z

232

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

233

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

234

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

235

Neutron–mirror-neutron oscillations in a trap  

Science Journals Connector (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 and O. Lychkovskiy

2008-06-27T23:59:59.000Z

236

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...

237

Recent Results in Diffractive ep Scattering at HERA  

E-Print Network [OSTI]

Recent Results in Diffractive ep Scattering at HERA Introduction to diffraction in ep Exclusive Diffraction in ep Scattering Matthew Beckingham 2 Diffraction Lepton-hadron (-p) or hadron-hadron (p to interpret in (p)QCD? #12;Lake Louise 06 Diffraction in ep Scattering Matthew Beckingham 3 Diffraction

238

High mass diffraction at the LHC  

E-Print Network [OSTI]

We use a Monte Carlo implementation of recently developped models of exclusive diffractive W, top, Higgs and stop productions to assess the sensitivity of the LHC experiments.

C. Royon

2005-07-08T23:59:59.000Z

239

Encircled energy of diffracted converging spherical waves  

Science Journals Connector (OSTI)

We studied the diffraction phenomenon of a circular aperture that was illuminated by a monochromatic converging spherical wave. The theoretical part of this study was based on the...

Li, Yajun

1983-01-01T23:59:59.000Z

240

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...

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

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...

242

Surface Studies by Low-Energy Electron Diffraction and Reflection High-Energy-Electron Diffraction  

Science Journals Connector (OSTI)

In this chapter, we present the basic concepts of the low-energy electron diffraction (LEED) and reflection high-energy electron diffraction (RHEED) experiments. The main goal is to provide an overview of the ...

P. Laukkanen; J. Sadowski; M. Guina

2012-01-01T23:59:59.000Z

243

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

244

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

245

Large aperture diffractive space telescope  

DOE Patents [OSTI]

A large (10's of meters) aperture space telescope including two separate spacecraft--an optical primary objective lens functioning as a magnifying glass and an optical secondary functioning as an eyepiece. The spacecraft are spaced up to several kilometers apart with the eyepiece directly behind the magnifying glass "aiming" at an intended target with their relative orientation determining the optical axis of the telescope and hence the targets being observed. The objective lens includes a very large-aperture, very-thin-membrane, diffractive lens, e.g., a Fresnel lens, which intercepts incoming light over its full aperture and focuses it towards the eyepiece. The eyepiece has a much smaller, meter-scale aperture and is designed to move along the focal surface of the objective lens, gathering up the incoming light and converting it to high quality images. The positions of the two space craft are controlled both to maintain a good optical focus and to point at desired targets which may be either earth bound or celestial.

Hyde, Roderick A. (Livermore, CA)

2001-01-01T23:59:59.000Z

246

Neutron Sciences at Oak Ridge National Laboratory  

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

Research Research Find out how neutron scattering can benefit your research. Call for Proposals Proposals for beam time at HFIR and SNS will be accepted via the web-based proposal system until 11:59 a.m. EST, (NOON) Wednesday, February 26, 2014. Comprehensive phonon "map" offers direction for engineering new thermoelectric devices. Comprehensive phonon "map" offers direction for engineering new thermoelectric devices. High-pressure studies of rare earth material could lead to lighter, cheaper magnets High-pressure studies of rare earth material could lead to lighter, cheaper magnets Unfrozen mystery: H2O reveals a new secret Unfrozen mystery: H2O reveals a new secret Neutron scattering workshop promotes high-pressure research Neutron scattering workshop promotes high-pressure research.

247

Extreme ultraviolet interferometric measurements of diffraction-limited optics  

SciTech Connect (OSTI)

At-wavelength interferometric measurements of recently fabricated extreme ultraviolet (EUV) microstepper projection optics have revealed the highest performance for prototype EUV lithographic systems observed to date. The phase-shifting point diffraction interferometer is used to measure and align these two-mirror, multilayer-coated Schwarzschild optical systems designed with a numerical aperture of 0.088 and operating at 13.4 nm wavelength. Root-mean-square wave front error magnitudes as small as 0.60 nm have been achieved, actually exceeding the design tolerance set for these objectives. (c) 1999 American Vacuum Society.

Goldberg, Kenneth A. [Center for X-Ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Center for X-Ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Naulleau, Patrick [Center for X-Ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Center for X-Ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Bokor, Jeffrey [Center for X-Ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States) [Center for X-Ray Optics, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); EECS Department, University of California, Berkeley, California 94720 (United States)

1999-11-01T23:59:59.000Z

248

Diffractive parton distributions from H1 data  

E-Print Network [OSTI]

We analyse the latest H1 large rapidity gap data to obtain diffractive parton distributions, using a procedure based on perturbative QCD, and compare them with distributions obtained from the simplified Regge factorisation type of analysis. The diffractive parton densities and structure functions are made publicly available.

Martin, A D; Watt, G

2007-01-01T23:59:59.000Z

249

Diffractive parton distributions from H1 data  

E-Print Network [OSTI]

We analyse the latest H1 large rapidity gap data to obtain diffractive parton distributions, using a procedure based on perturbative QCD, and compare them with distributions obtained from the simplified Regge factorisation type of analysis. The diffractive parton densities and structure functions are made publically available.

A. D. Martin; M. G. Ryskin; G. Watt

2006-09-26T23:59:59.000Z

250

Ultrasonic imaging with limited-diffraction beams  

E-Print Network [OSTI]

Limited-diffraction beams are a class of waves that may be localized in space and time. Theoretically, these beams are propagation invariant and can propagate to an infinite distance without spreading. In practice, when these beams are produced with wave sources of a finite aperture and energy, they have a very large depth of field, meaning that they can keep a small beam width over a large distance. Because of this property, limited-diffraction beams may have applications in various areas such as medical imaging and tissue characterization. In this paper, fundamentals of limited-diffraction beams are reviewed and the studies of these beams are put into a unified theoretical framework. Theory of limited-diffraction beams is further developed. New limited-diffraction solutions to Klein-Gordon Equation and Schrodinger Equation, as well as limited-diffraction solutions to these equations in confined spaces are obtained. The relationship between the transformation that converts any solutions to an (-1)-dimensional wave equation to limited-diffraction solutions of an -dimensional equation and the Lorentz transformation is clarified and extended. The transformation is also applied to the Klein-Gordon Equation. In addition, applications of limited-diffraction beams are summarized.

Jian-yu Lu

2006-03-28T23:59:59.000Z

251

Novel features of diffraction at the LHC  

Science Journals Connector (OSTI)

Interest and problems in the studies of diffraction at LHC are highlighted. Predictions for the global characteristics of proton–proton interactions at the LHC energy are given. Potential discoveries of the antishadow scattering mode which is allowed in principle by unitarity and diffractive scattering conjugated with high-ET jets are discussed.

V A Petrov; A V Prokudin; S M Troshin; N E Tyurin

2001-01-01T23:59:59.000Z

252

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

253

Defining Electron Backscatter Diffraction Resolution  

SciTech Connect (OSTI)

Automated electron backscatter diffraction (EBSD) mapping systems have existed for more than 10 years [1,2], and due to their versatility in characterizing multiple aspects of microstructure, they have become an important tool in microscale crystallographic studies. Their increasingly widespread use however raises questions about their accuracy in both determining crystallographic orientations, as well as ensuring that the orientation information is spatially correct. The issue of orientation accuracy (as defined by angular resolution) has been addressed previously [3-5]. While the resolution of EBSD systems is typically quoted to be on the order of 1{sup o}, it has been shown that by increasing the pattern quality via acquisition parameter adjustment, the angular resolution can be improved to sub-degree levels. Ultimately, the resolution is dependent on how it is identified. In some cases it can be identified as the orientation relative to a known absolute, in others as the misorientation between nearest neighbor points in a scan. Naturally, the resulting values can be significantly different. Therefore, a consistent and universal definition of resolution that can be applied to characterize any EBSD system is necessary, and is the focus of the current study. In this work, a Phillips (FEI) XL-40 FEGSEM coupled to a TexSEM Laboratories OIM system was used. The pattern capturing hardware consisted of both a 512 by 512 pixel SIT CCD camera and a 1300 by 1030 pixel Peltier cooled CCD camera. Automated scans of various sizes, each consisting of 2500 points, were performed on a commercial-grade single crystal silicon wafer used for angular resolution measurements. To adequately quantify angular resolution for all possible EBSD applications we define two angular values. The first is {omega}{sub center}, the mean of the misorientation angle distribution between all scan points and the scan point coincident to the calibration source (typically the scan center). The {omega}{sub center} value is used to describe the overall system resolution, as it effectively quantifies the deviation of all orientations in the scan relative to the diffraction pattern least affected by distortions. The second is {omega}{sub max}, the largest misorientation angle possible between any pair of points in the dataset, and describes the worst possible case. Fig. 1 shows the effects of scan size and captured pattern resolution (bin size) on both angular values, illustrating that smaller scan and bin sizes have the effect of increasing angular resolution. However, it can be observed that the benefits of utilizing smaller bin sizes (and consequently slower data collection) diminish with scan size. Fig. 2 shows the effect of the number of pixels used in the Hough transform (defined as the ratio of pixels used to maximum possible pixels) on the angular values. It can be seen that the best angular resolutions are achieved at a pixel ratio of 0.80, again illustrating that the use of higher resolutions is not always beneficial. As evidenced by the results, the use of {omega}{sub center} and {omega}{sub max} not only permits the characterization of the angular resolution of an EBSD system, but they allow for a more efficient utilization of the system by identifying appropriate settings depending on the desired angular resolution [6].

El-Dasher, B S; Rollett, A D

2005-02-07T23:59:59.000Z

254

Secrets of superconductivity revealed  

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

material Cerium-Colbalt-Indium5 reveals new secrets about how superconductivity and magnetism can be related. January 3, 2014 Simon Gerber, first author of the publication on the...

255

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

256

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

257

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

258

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

259

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

260

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 diffraction reveals" 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

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

262

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

263

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

264

Biology and Soft Matter Division - ORNL Neutron Sciences  

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

Home › Neutron Sciences Directorate › Biology and Soft Matter Division Home › Neutron Sciences Directorate › Biology and Soft Matter Division Biology and Soft Matter Division Paul Langan, BSMD Director BSMD Director Paul Langan. The Biology and Soft Matter Division (BSMD) operates an external user program for biological and soft matter research using neutron techniques at SNS and HFIR. Division personnel enable the research initiated by external users by acting as instrument responsible scientists and local contacts on a range of different beam lines. BSMD works closely with the Center for Structural Molecular Biology. Diffraction, small-angle scattering, and reflectometry are ideal methods for studying structure and organization from the atomic to the micron length scales, and neutron spectroscopic methods characterize self and

265

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

266

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

267

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

268

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

269

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

270

Visualizations of the Exclusive Central Diffraction  

E-Print Network [OSTI]

The case of the low invariant mass exclusive central diffractive production is considered in the general theoretical framework. It is shown that diffractive patterns (differential cross-sections on variables like transfer momenta squared, the azimuthal angle between final hadrons and their combinations) can serve as a unique tool to explore the picture of the $pp$ interaction and falsify theoretical models. Basic kinematical and dynamical properties of the process are considered in detail. As an example, visualizations of diffractive patterns in the model with three pomerons for processes $p+p\\to p+R+p$ and $p+p\\to p+\\pi^{+}\\pi^{-}+p$ are presented.

R. A. Ryutin

2014-09-19T23:59:59.000Z

271

Published Research 2009 | ORNL Neutron Sciences  

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

9 9 Most publications are in Adobe Portable Document Format. Download Adobe Reader. For more information about any of these publications, please contact the Neutrons Sciences Communications Office. Primary Author Index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A Abdou A., Wendel M., Felde D., Riemer B., "CFD validation of gas injection in flowing mercury over vertical smooth and grooved wall", Proceedings of the ASME Fluids Engineering Division Summer Conference 2009. Agamalian M., Carpenter J. M., Richardson J. W., "Validity of the Darwin and Ewald reflectivity functions in the range of the far wings: neutron diffraction study", Physics Letters A 373, 292-295. Alfonsov A., Vavilova E., Kataev V., Buchner B., Podlesnyak A., Russina M., Furrer A., Strassle Th., Pomjakushina E., Conder K., Khomskii

272

Published Research 2009 | ORNL Neutron Sciences  

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

09 09 Published Research 2009 Most publications are in Adobe Portable Document Format. Download Adobe Reader. For more information about any of these publications, please contact the Neutrons Sciences Communications Office. Primary Author Index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A A. Abdou, M. Wendel, D. Felde, and B. Riemer, "CFD validation of gas injection in flowing mercury over vertical smooth and grooved wall," Proceedings of the ASME Fluids Engineering Division Summer Conference 2009, FEDSM2009 1 (Part B), 1061-1067 (2009). M. Agamalian, J. M. Carpenter, and J. W. Richardson, "Validity of the Darwin and Ewald reflectivity functions in the range of the far wings: Neutron diffraction study." Physics Letters A 373, 292-295 (2009). A. Alfonsov, E. Vavilova, V. Kataev, B. Büchner, A. Podlesnyak, M.

273

Published Research 2006 | ORNL Neutron Sciences  

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

6 6 Most publications are in Adobe Portable Document Format. Download Adobe Reader. For more information about any of these publications, please contact the Neutrons Sciences Communications Office. Primary Author Index: B C E F G H I J K L M N O P R S T W X Y B E. D. Bauer, A. D. Christianson, J. S. Gardner, V. A. Sidorov, J. D. Thompson, J. L. Sarrao, and M. F. Hundley, "Physical properties of the ferromagnetic heavy-fermion compound UIr2Zn20," Physical Review B 74, (Oct 2006). B. Bennett, P. Langan, L. Coates, M. Mustyakimov, B. Schoenborn, E.E. Howell, C. Dealwis, "Neutron diffraction studies of Escherichia coli dihydrofolate reductase complexed with methotrexate," PNAS of the United States of America 103(49), pp. 18493-8 (5 Dec. 2006). M. L. Benson, P. K. Liaw, H. Choo, T. A. Saleh, D. W. Brown, M. R.

274

Neutron charge radius and the neutron electric form factor  

Science Journals Connector (OSTI)

For nearly forty years, the Galster parametrization has been employed to fit existing data for the neutron electric form factor, GEn, vs the square of the four-momentum transfer, Q2. Typically this parametrization is constrained to be consistent with experimental data for the neutron charge radius. However, we find that the Galster form does not have sufficient freedom to accommodate reasonable values of the radius without constraining or compromising the fit. In addition, the GEn data are now at sufficient precision to motivate a two-parameter fit (or three parameters if we include thermal neutron data). Here we present a modified form of a two-dipole parametrization that allows this freedom and fits both GEn (including recent data at both low and high four-momentum transfer) and the charge radius well with simple, well-defined parameters. Analysis reveals that the Galster form is essentially a two-parameter approximation to the two-dipole form but becomes degenerate if we try to extend it naturally to three parameters.

T. R. Gentile and C. B. Crawford

2011-05-12T23:59:59.000Z

275

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

276

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

277

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. Heyrovská

1992-01-01T23:59:59.000Z

278

Phenomenology of single and double diffraction dissociation  

E-Print Network [OSTI]

Predictions of the gap-probability renormalization model for single and double diffraction dissociation cross sections in proton-proton collisions at the LHC are presented and compared with recent CMS measurements.

Konstantin Goulianos

2013-10-21T23:59:59.000Z

279

Diffractive parton distributions from perturbative QCD  

E-Print Network [OSTI]

The asymptotic collinear factorisation theorem, which holds for diffractive deep-inelastic scattering, has important modifications in the sub-asymptotic HERA regime. We use perturbative QCD to quantify these modifications. The diffractive parton distributions are shown to satisfy an inhomogeneous evolution equation. We emphasise that it is necessary to include both the gluonic and sea-quark t-channel components of the perturbative Pomeron. The corresponding Pomeron-to-parton splitting functions are derived in the Appendix.

Martin, A D; Watt, G

2005-01-01T23:59:59.000Z

280

Diffractive parton distributions from perturbative QCD  

E-Print Network [OSTI]

The asymptotic collinear factorisation theorem, which holds for diffractive deep-inelastic scattering, has important modifications in the sub-asymptotic HERA regime. We use perturbative QCD to quantify these modifications. The diffractive parton distributions are shown to satisfy an inhomogeneous evolution equation. We emphasise that it is necessary to include both the gluonic and sea-quark t-channel components of the perturbative Pomeron. The corresponding Pomeron-to-parton splitting functions are derived in the Appendix.

A. D. Martin; M. G. Ryskin; G. Watt

2005-04-15T23:59:59.000Z

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

Nuclear diffractive structure functions at high energies  

E-Print Network [OSTI]

A future high-energy electron-ion collider would explore the non-linear weakly-coupled regime of QCD, and test the Color Glass Condensate (CGC) approach to high-energy scattering. Hard diffraction in deep inelastic scattering off nuclei will provide many fundamental measurements. In this work, the nuclear diffractive structure function F_{2,A}^D is predicted in the CGC framework, and the features of nuclear enhancement and suppression are discussed.

C. Marquet; H. Kowalski; T. Lappi; R. Venugopalan

2008-05-30T23:59:59.000Z

282

Diffractive photon production at the LHC  

Science Journals Connector (OSTI)

In this paper we study photon production in single and double diffractive processes considering the resolved pomeron model. We estimate the rapidity and transverse momentum dependence of the cross section for the diffractive double photon and photon+jet production. A comparison with the inclusive production is presented. We predict large values for the total cross sections, which make the experimental analysis of these observables feasible at LHC energies.

C. Brenner Mariotto and V. P. Goncalves

2013-10-22T23:59:59.000Z

283

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

284

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

285

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

286

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

287

Detonation diffraction in a multi-step channel .  

E-Print Network [OSTI]

??This research investigated multiple detonation diffraction events in order to better understand the limits and benefits of diffraction strategies with respect to pulse detonation engine… (more)

Juillet, Daniel M.

2010-01-01T23:59:59.000Z

288

Binary high-frequency-carrier diffractive optical elements: electromagnetic theory  

Science Journals Connector (OSTI)

Using rigorous electromagnetic diffraction theory, we evaluate the potential performance and the limitations of coding diffractive optical elements in the form of a...

Noponen, Eero; Turunen, Jari

1994-01-01T23:59:59.000Z

289

Nanoparticle diffraction gratings for DNA detection on photopatterned glass substrates  

E-Print Network [OSTI]

Sendroiu and R. M. Corn: Nanoparticle diffraction gratingsSendroiu and R. M. Corn: Nanoparticle diffraction gratingsthe principle of the nanoparticle-based DNA detection assay

Sendroiu, Luliana E; Corn, Robert M

2008-01-01T23:59:59.000Z

290

Cosmic ray modulation studies with Lead-free Gulmarg neutron monitor  

E-Print Network [OSTI]

A lead-free neutron monitor operating at High Altitude Research Laboratory (HARL), Gulmarg optimized for detecting 2.45 MeV neutron bursts produced during the atmospheric lightning discharges is also concurrently used for studying background neutron component present in the atmosphere. These background neutrons are produced due to the interaction of primary cosmic rays with the atmospheric constituents. In order to study and extract the information about the yield of the neutron production during transient atmospheric lightning discharges, the system is continuously operated to monitor and record the cosmic ray produced background secondary neutrons in the atmosphere. The data analysis of the background neutrons recorded by Lead-Free Gulmarg Neutron Monitor (LFGNM) has convincingly established that the modulation effects due to solar activity phenomena compare very well with those monitored by the worldwide IGY or NM64 type neutron monitors which have optimum energy response relatively towards the higher energy regime of the cosmic rays. The data has revealed various types of modulation phenomena like diurnal variation, Forbush decrease etc. during its entire operational period. However, a new kind of a periodic/seasonal variation pattern is also revealed in the data from September 2007 to September 2012, which is seen to be significantly consistent with the data recorded by Emilio Segre observatory, Israel (ESOI) Neutron Monitor. Interestingly, both these neutron monitors have comparable latitude and altitude. However, the same type of consistency is not observed in the data recorded by the other conventional neutron monitors operating across the globe.

M. A. Darzi; P. M. Ishtiaq; T. A. Mir; S. Mufti; G. N. Shah

2013-12-21T23:59:59.000Z

291

Experimental observation of acoustic sub-harmonic diffraction by a grating  

SciTech Connect (OSTI)

A diffraction grating is a spatial filter causing sound waves or optical waves to reflect in directions determined by the frequency of the waves and the period of the grating. The classical grating equation is the governing principle that has successfully described the diffraction phenomena caused by gratings. However, in this work, we show experimental observation of the so-called sub-harmonic diffraction in acoustics that cannot be explained by the classical grating equation. Experiments indicate two physical phenomena causing the effect: internal scattering effects within the corrugation causing a phase shift and nonlinear acoustic effects generating new frequencies. This discovery expands our current understanding of the diffraction phenomenon, and it also makes it possible to better design spatial diffraction spectra, such as a rainbow effect in optics with a more complicated color spectrum than a traditional rainbow. The discovery reveals also a possibly new technique to study nonlinear acoustics by exploitation of the natural spatial filtering effect inherent to an acoustic diffraction grating.

Liu, Jingfei, E-mail: benjamin.jf.liu@gatech.edu; Declercq, Nico F., E-mail: declercqdepatin@gatech.edu [Laboratory for Ultrasonic Nondestructive Evaluation “LUNE,” Georgia Tech Lorraine, Georgia Tech-CNRS UMI2958, Georgia Institute of Technology, 2, rue Marconi, Metz 57070 (France)

2014-06-28T23:59:59.000Z

292

Publications from Research Conducted at SNAP | ORNL Neutron Sciences  

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

Publications from Research Conducted at SNAP Publications from Research Conducted at SNAP 2013 Publications Boehler R., Guthrie M., Molaison J.J., dos Santos A. M., Sinogeikin S., Machida S., Pradhan N., Tulk C. A., "Large-volume diamond cells for neutron diffraction above 90 GPa", High Pressure Research 33, 546-554 (2013). Guthrie M., Boehler R., Tulk C. A., Molaison J. J., dos Santos A. M., Li K., Hemley R. J., "Neutron diffraction observations of interstitial protons in dense ice", Proceedings of the National Academy of Sciences of the USA 110, 10552-10556 (2013). Hirai S., dos Santos A. M., Shapiro M. C., Molaison J. J., Pradhan N., Guthrie M., Tulk C. A., Fisher I. R., Mao W. L., "Giant atomic displacement at a magnetic phase transition in metastable Mn3O4", Physical

293

Two-neutron correlations in microscopic wave functions of He-6, He-8 and C-12  

E-Print Network [OSTI]

Two-neutron densities obtained from microscopic wave functions of $^6$He and $^8$He are investigated to reveal di-neutron correlations. In particular, the comparison of the two-neutron density with the product of one-neutron densities is useful for a quantitative discussion of di-neutron correlations. The calculations show that the S=0 spatial two-neutron correlation increases at the surface of $^6$He$(0^+_1)$ and $^8$He$(0^+_2)$. The enhancement is remarkable in the $^6$He$(0^+_1)$ ground state but not as prominent in the $^8$He$(0^+_1)$ ground state. Configuration mixing of many Slater determinants is essential to describe the di-neutron correlations. Two-neutron densities in $^{12}$C wave functions with $\\alpha$-cluster structures are also studied.

Yoshiko Kanada-En'yo; Hans Feldmeier; Tadahiro Suhara

2011-07-28T23:59:59.000Z

294

Biotechnology & Energy Highlights | Neutron Science | ORNL  

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

Biotechnology & Energy Biotechnology & Energy SHARE Biotechnology and Energy Highlights 1-10 of 10 Results Neutron Imaging Reveals Lithium Distribution in Lithium-Air Electrodes January 01, 2013 - Using neutron-computed tomography, researchers at the CG-1D neutron imaging instrument at Oak Ridge National Laboratory's High Flux Isotope Reactor (HFIR) have successfully mapped the three-dimensional spatial distribution of lithium products in electrochemically discharged lithium-air cathodes. Theory meets experiment: structure-property relationships in an electrode material for solid-oxide fuel cells December 01, 2012 - Fuel cell technology is one potentially very efficient and environmentally friendly way to convert the chemical energy of fuels into electricity. Solid-oxide fuel cells (SOFCs) can convert a

295

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

296

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

297

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

298

On the microstructure of nanoporous gold: an x-ray diffraction study  

SciTech Connect (OSTI)

The evolution of the grain structure, internal stresses, and the lattice misorientations of nanoporous gold (npAu) during dealloying of bulk (3D) Ag-Au alloy samples was studied by various in-situ and ex-situ X-ray diffraction techniques including powder and Laue diffraction. The experiments reveal that the dealloying process preserves the original crystallographic structure, but leads to a small spread in orientations within individual grains. Furthermore, most grains develop in-plane tensile stress. The feature size of the developing nanoporous structure increases with increasing dealloying time.

Van Petegem, S; Brandstetter, S; Maa?, R; Schmitt, B; Borca, C; Van Swygenhoven, H; Hodge, A M; El-Dasher, B S; Biener, J

2008-08-26T23:59:59.000Z

299

Breast Tissue Imaging | ORNL Neutron Sciences  

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

diffraction reveals semiconducting phase and contributes to new diffraction reveals semiconducting phase and contributes to new understanding of iron-based superconductors Research Contacts: Jun Zhao and Huibo Cao August 2013 Superconductors-materials that lose their resistance to the flow of electric currents below a certain transition temperature-have a myriad of actual and potential applications ranging from super-efficient electrical cables to more powerful magnets. Increasing the superconducting temperature is needed to realize many of the prospective applications, and researchers are investigating the origin of superconducting behavior as a key to improved performance. Researchers at Oak Ridge National Laboratory (ORNL) have identified an antiferromagnetic semiconducting phase that could be the true parent phase of new iron-based superconductors. The discovery defines

300

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

Note: This page contains sample records for the topic "neutron diffraction reveals" 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 Imaging in an Active Interrogation Environment  

SciTech Connect (OSTI)

We have developed a thermal-neutron coded-aperture imager that reveals the locations of hydrogenous materials from which thermal neutrons are being emitted. This imaging detector can be combined with an accelerator to form an active interrogation system in which fast neutrons are produced in a heavy metal target by means of excitation by high energy photons. The photo-induced neutrons can be either prompt or delayed, depending on whether neutron-emitting fission products are generated. Provided that there are hydrogenous materials close to the target, some of the photo-induced neutrons slow down and emerge from the surface at thermal energies. These neutrons can be used to create images that show the location and shape of the thermalizing materials. Analysis of the temporal response of the neutron flux provides information about delayed neutrons from induced fission if there are fissionable materials in the target. The combination of imaging and time-of-flight discrimination helps to improve the signal-to-background ratio. It is also possible to interrogate the target with neutrons, for example using a D-T generator. In this case, an image can be obtained from hydrogenous material in a target without the presence of heavy metal. In addition, if fissionable material is present in the target, probing with fast neutrons can stimulate delayed neutrons from fission, and the imager can detect and locate the object of interest, using appropriate time gating. Operation of this sensitive detection equipment in the vicinity of an accelerator presents a number of challenges, because the accelerator emits electromagnetic interference as well as stray ionizing radiation, which can mask the signals of interest.

Vanier, Peter E. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Forman, Leon [Ion Focus Technology, Inc., Miller Place, NY 11764 (United States); Norman, Daren R. [Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

2009-03-10T23:59:59.000Z

302

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

303

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

304

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...

305

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...

306

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

307

Diffractive Higgs boson photoproduction in $?p$ process  

E-Print Network [OSTI]

We explore an alternative process for the diffractive Higgs boson production in peripheral pp collisions arising from Double Pomeron Exchange in photon-proton interaction. We introduce the impact factor formalism in order to enable the gluon ladder exchange in the photon-proton subprocess, and to permit the central Higgs production. The event rate for the diffractive Higgs production in central rapidity is estimated to be about 0.6 pb at Tevatron and LHC energies. This result is higher than predictions from other approaches for diffractive Higgs production, showing that the alternative production process leads to an enhanced signal for the detection of the Higgs boson at hadron colliders. Our results are compared to those obtained from a similar approach proposed by the Durham group. In this way we may examine the future developments in its application to pp and AA collisions.

M. B. Gay Ducati; G. G. Silveira

2008-12-05T23:59:59.000Z

308

Ultra-high density diffraction grating  

SciTech Connect (OSTI)

A diffraction grating structure having ultra-high density of grooves comprises an echellette substrate having periodically repeating recessed features, and a multi-layer stack of materials disposed on the echellette substrate. The surface of the diffraction grating is planarized, such that layers of the multi-layer stack form a plurality of lines disposed on the planarized surface of the structure in a periodical fashion, wherein lines having a first property alternate with lines having a dissimilar property on the surface of the substrate. For example, in one embodiment, lines comprising high-Z and low-Z materials alternate on the planarized surface providing a structure that is suitable as a diffraction grating for EUV and soft X-rays. In some embodiments, line density of between about 10,000 lines/mm to about 100,000 lines/mm is provided.

Padmore, Howard A.; Voronov, Dmytro L.; Cambie, Rossana; Yashchuk, Valeriy V.; Gullikson, Eric M.

2012-12-11T23:59:59.000Z

309

Neutron irradiation effects on gallium nitride-based Schottky diodes  

SciTech Connect (OSTI)

Depth-resolved cathodoluminescence spectroscopy (DRCLS), time-resolved surface photovoltage spectroscopy, X-ray photoemission spectroscopy (XPS), and current-voltage measurements together show that fast versus thermal neutrons differ strongly in their electronic and morphological effects on metal-GaN Schottky diodes. Fast and thermal neutrons introduce GaN displacement damage and native point defects, while thermal neutrons also drive metallurgical reactions at metal/GaN interfaces. Defect densities exhibit a threshold neutron fluence below which thermal neutrons preferentially heal versus create new native point defects. Scanning XPS and DRCLS reveal strong fluence- and metal-dependent electronic and chemical changes near the free surface and metal interfaces that impact diode properties.

Lin, Chung-Han; Katz, Evan J.; Zhang, Zhichun [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States)] [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States); Qiu, Jie; Cao, Lei [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)] [Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Mishra, Umesh K. [Departments of Electrical and Computer Engineering and Materials Science and Engineering, University of California, Santa Barbara, California 93106 (United States)] [Departments of Electrical and Computer Engineering and Materials Science and Engineering, University of California, Santa Barbara, California 93106 (United States); Brillson, Leonard J. [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States) [Department of Electrical and Computer Engineering, The Ohio State University, Columbus Ohio 43210 (United States); Department of Physics and Center for Materials Research, The Ohio State University, Columbus, Ohio 43210 (United States)

2013-10-14T23:59:59.000Z

310

Rotational and magnetic field instabilities in neutron stars  

SciTech Connect (OSTI)

In this short review we present recent results on the dynamics of neutron stars and their magnetic fields. We discuss the progress that has been made, during the last 5 years, in understanding the rotational instabilities with emphasis to the one due to the f-mode, the possibility of using gravitational wave detection in constraining the parameters of neutron stars and revealing the equation of state as well as the detectability of gravitational waves produced during the unstable phase of a neutron star’s life. In addition we discuss the dynamics of extremely strong magnetic fields observed in a class of neutron stars (magnetars). Magnetic fields of that strength are responsible for highly energetic phenomena (giant flares) and we demonstrate that the analysis of the emitted electromagnetic radiation can lead in constraining the parameters of neutron stars. Furthermore, we present our results from the study of such violent phenomena in association with the emission of gravitational radiation.

Kokkotas, Kostas D. [Theoretical Astrophysics, IAAT, Eberhard Karls University of Tübingen, Tübingen 72076 (Germany)

2014-01-14T23:59:59.000Z

311

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

312

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

313

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...

314

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

315

Odd CP contributions to diffractive processes  

Science Journals Connector (OSTI)

We investigate contributions to diffractive scattering, which are odd under C and P parity. Comparison of p-p¯ and p-p scattering indicates that these odderon contributions are very small and we show how a diquark clustering in the proton can explain this effect. A good probe for the odderon exchange is the photo- and electroproduction of pseudoscalar mesons. We concentrate on the ?0 and show that the quasielastic ?0 production is again strongly suppressed for a diquark structure of the proton whereas the cross sections for diffractive proton dissociation are larger by orders of magnitude and rather independent of the proton structure.

Michael Rueter; H. G. Dosch; O. Nachtmann

1998-11-30T23:59:59.000Z

316

Diffraction at the Tevatron and the LHC  

E-Print Network [OSTI]

In these lectures, we present and discuss the most recent results on inclusive diffraction at the Tevatron collider and give the prospects at the LHC. We also describe the search for exclusive events at the Tevatron. Of special interest is the exclusive production of Higgs boson and heavy objects ($W$, top, stop pairs) at the LHC which will require precise measurements and analyses of inclusive and exclusive diffraction to constrain further the gluon density in the pomeron. At the end of these lectures, we describe the projects to install forward detectors at the LHC to fulfil these measurements.

C. Royon

2008-05-02T23:59:59.000Z

317

Polyelectrolyte biomaterials - Research Highlights | ORNL Neutron Sciences  

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

Home › Research › Highlights › Polyelectrolyte biomaterials Home › Research › Highlights › Polyelectrolyte biomaterials Detecting the shape of polymer chains inside polyelectrolyte biomaterials Bio-SANS research for replacing cartilage in the spine and knees Research Contact: Marie Markarian Feb. 2012, Written by Agatha Bardoel Left: neutron scattering with contrast variation reveals the coil conformation of single polymer molecules in a blend of PSS and PDADMA. Contrast variation is achieved by deuteration of some of the PSS molecules (D-PSS) in the mixture. Right: The slope of the scattering curve exhibits a power law dependence Q-2, which is a characteristic signature of the random coil conformation of a polymer chain molecule. Left: neutron scattering with contrast variation reveals the coil conformation of single polymer molecules in a blend of PSS and PDADMA.

318

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

319

Device for Writing the Time Tail from Spallation Neutron Pulses  

SciTech Connect (OSTI)

Recent work at Los Alamos Neutron Science Center (LANSCE), has shown that there are large gains in neutron beam intensity to be made by using coupled moderators at spallation neutron sources. Most of these gains result from broadening the pulse-width in time. However the accompanying longer exponential tail at large emission times can be a problem in that it introduces relatively large beam-related backgrounds at high resolutions. We have designed a device that can reshape the moderated neutron beam by cutting the time-tail so that a sharp time resolution can be re-established without a significant loss in intensity. In this work the basic principles behind the tail-cutter and some initial results of Monte Carlo simulations are described. Unwanted neutrons in the long time-tail are diffracted out of the transmitted neutron beam by a nested stack of aperiodic multi-layers, rocking at the same frequency as the source. Nested aperiodic multi-layers have recently been used at X-ray sources and as band-pass filters in quasi-Laue neutron experiments at reactor neutron sources. Optical devices that rock in synchronization with a pulsed neutron beam are relatively new but are already under construction at LANSCE. The tail-cutter described here is a novel concept that uses existing multi-layer technology in a new way for spallation neutrons. Coupled moderators in combination with beam shaping devices offer the means of increasing flux whilst maintaining a sharp time distribution. A prototype device is being constructed for the protein crystallography station at LANSCE. The protein crystallography station incorporates a water moderator that has been judiciously coupled in order to increase the flux over neutron energies that are important to structural biology (3-80meV). This development in moderator design is particularly important because protein crystallography is flux limited and because conventional ambient water and cold hydrogen moderators do not provide relatively large neutron fluxes over this neutron energy range.

Langan, P. (Paul); Schoenborn, Benno P.; Langan, P. (Paul); Schoenborn, Benno P.; Daemen, L. L. (Luc L.)

2001-01-01T23:59:59.000Z

320

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

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

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

322

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

323

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...

324

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...

325

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...

326

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...

327

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

328

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...

329

X-Ray Diffraction The X-Ray Diffraction facility is equipped with state-of-the-art  

E-Print Network [OSTI]

X-Ray Diffraction The X-Ray Diffraction facility is equipped with state-of-the-art diffractometers offering both single crystal and powder X-Ray diffraction. Powder X-Ray Diffraction High resolution data For more details on powder X-Ray analysis contact Dr J Hriljac on 0121 414 4458 or email: j

Birmingham, University of

330

Chemical & EngChemical/Engineering Materials Division | Neutron Science |  

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

Chemical and Engineering Materials Division Chemical and Engineering Materials Division SHARE Chemical and Engineering Materials Division CEMD Director Mike Simonson The Chemical and Engineering Materials Division (CEMD) supports neutron-based research at SNS and HFIR in understanding the structure and dynamics of chemical systems and novel engineering materials. The user community takes advantage of division-supported capabilities of neutron scattering for measurements over wide ranges of experimental and operating conditions, including studies of chemical and physical changes in situ. User experiments with diffraction, small-angle scattering, inelastic and quasielastic scattering, and neutron imaging instruments address a range of problems in chemistry and in engineering materials research. Current areas of research supported by the division include the structure

331

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

332

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

333

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

334

A computational inverse diffraction grating problem  

E-Print Network [OSTI]

Mar 2, 2012 ... od and a variational (finite element) method have been developed in [3,4]. ... problems in diffractive optics, which is to design a grating structure that .... where the free-space quasiperiodic Green function is given ex- plicitly as.

2012-02-29T23:59:59.000Z

335

DIFFRACTION STUDIES OF ICE Alexe BOSAK  

E-Print Network [OSTI]

Ic 28o halo observed at least 7 times since 1629 octahedral particles of ice Ic! #12;Cooling downDIFFRACTION STUDIES OF ICE Alexeï BOSAK European Synchrotron Radiation Facility #12;Ice as the mild threat ice Ih the only ice in the crust #12;Ice as the absolute weapon Ice IX : melting point 45.8°C

Titov, Anatoly

336

X-Ray Diffraction on NIF  

SciTech Connect (OSTI)

The National Ignition Facility (NIF) is currently a 192 beam, 1.6 MJ laser. NIF Ramp-Compression Experiments have already made the relevant exo-planet pressure range from 1 to 50 Mbar accessible. We Proposed to Study Carbon Phases by X-Ray Diffraction on NIF. Just a few years ago, ultra-high pressure phase diagrams for materials were very 'simple'. New experiments and theories point out surprising and decidedly complex behavior at the highest pressures considered. High pressures phases of aluminum are also predicted to be complex. Recent metadynamics survey of carbon proposed a dynamic pathway among multiple phases. We need to develop diagnostics and techniques to explore this new regime of highly compressed matter science. X-Ray Diffraction - Understand the phase diagram/EOS/strength/texture of materials to 10's of Mbar. Strategy and physics goals: (1) Powder diffraction; (2) Begin with diamond; (3) Continue with metals etc.; (4) Explore phase diagrams; (5) Develop liquid diffraction; and (6) Reduce background/improve resolution.

Eggert, J H; Wark, J

2012-02-15T23:59:59.000Z

337

Estimating nanoparticle size from diffraction measurements  

Science Journals Connector (OSTI)

A Fourier transform of a Debye-Scherrer diffraction pattern can be used to estimate the characteristic size of nanoparticle samples. This method is insensitive to nanoparticle structure and therefore preferable to the Scherrer formula (which is unreliable because it assumes an underlying size-limited perfect crystal structure).

Hall, B.D.

2000-12-01T23:59:59.000Z

338

Near-field diffractive elements Daniel Marks  

E-Print Network [OSTI]

by a near-field diffractive element (NDE) that scatters the high-spatial-frequency components of the field susceptibility r , and the NDE is described by the susceptibilty r . The field obeys the equation 2 U r +k0 2 U r to first order in both the NDE and the sample susceptibilities. It is assumed that the background terms

Bhargava, Rohit

339

Diffraction at HERA, Tevatron and LHC  

E-Print Network [OSTI]

In this short review, we describe some of the results on diffraction from the Tevatron and give some prospects for the LHC. In particular, we discuss the search for exclusive events at the Tevatron and their importance for the LHC program/ We finish by presenting the project of installing forward detectors in the ATLAS collaboration at 220 and 420 m.

C. Royon

2009-04-14T23:59:59.000Z

340

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

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

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.

342

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

343

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 (0.23×10-13cm)2 for the charge distribution and (0.41×10-13cm)2 for the magnetic moment distribution with f2=0.08.

Katsumi Tanaka

1959-01-15T23:59:59.000Z

344

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

345

Elimination of ghosting artifacts from wavelength-shifting fiber neutron detectors  

SciTech Connect (OSTI)

Misassignment of neutron position (ghosting) produces artifacts which have been observed in wavelength-shifting (WLS) fiber detectors developed for time-of-flight (TOF) neutron powder diffraction. In position-sensitive detectors (PSDs) with WLS fiber encoding, thermal and cold neutrons interact with a monolithic {sup 6}LiF/ZnS:Ag scintillator screen, and scintillation photons are generated and transported through the crossed fibers to photomultipliers (PMTs). The neutron position is determined by photon counts in the PMTs within a preset time window. Ghosting occurs when neutrons hit the group boundaries of two neighboring PMTs for x-position multiplexing, which is modeled as resulting from a long travel length (about 3-5 mm) of a small number of scintillation photons. This model is supported by the change observed in aperture images when the threshold number for photon-pulses was adjusted for neutron event determination. When the threshold number of photon-pulses was set above 10 for each PMT, the ghost peaks in the aperture images and TOF spectra of powder diffraction were strongly suppressed or completely eliminated, and the intrinsic background levels of the WLS detectors were significantly reduced. Our result indicates that WLS fiber detector is a promising alternative for {sup 3}He PSDs for neutron scattering.

Wang, C. L.; Diawara, Y.; Hannan, B. W.; Hodges, J. P. [Instrument and Source Design Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Clonts, L. G. [Research Accelerator Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2013-01-15T23:59:59.000Z

346

Instrument and method for focusing x rays, gamma rays, and neutrons  

DOE Patents [OSTI]

A crystal-diffraction instrument or diffraction-grating instrument is described with an improved crystalline structure or grating spacing structure having a face for receiving a beam of photons or neutrons and diffraction planar spacing or grating spacing along that face with the spacing increasing progressively along the face to provide a decreasing Bragg diffraction angle for a monochromatic radiation and thereby increasing the usable area and acceptance angle. The increased planar spacing for the diffraction crystal is provided by the use of a temperature differential across the line structures with different compositions, by an individual crystalline structure with a varying composition and thereby a changing planar spacing along its face, and by combinations of these techniques. The increased diffraction grating element spacing is generated during the fabrication of the diffraction grating by controlling the cutting tool that is cutting the grooves or controlling the laser beam, electron beam, or ion beam that is exposing the resist layer, etc. It is also possible to vary this variation in grating spacing by applying a thermal gradient to the diffraction grating in much the same manner as is done in the crystal-diffraction case.

Smither, R.K.

1982-03-25T23:59:59.000Z

347

Instrument and method for focusing X-rays, gamma rays and neutrons  

DOE Patents [OSTI]

A crystal diffraction instrument or diffraction grating instrument with an improved crystalline structure or grating spacing structure having a face for receiving a beam of photons or neutrons and diffraction planar spacing or grating spacing along that face with the spacing increasing progressively along the face to provide a decreasing Bragg diffraction angle for a monochromatic radiation and thereby increasing the usable area and acceptance angle. The increased planar spacing for the diffraction crystal is provided by the use of a temperature differential across the crystalline structure, by assembling a plurality of crystalline structures with different compositions, by an individual crystalline structure with a varying composition and thereby a changing planar spacing along its face, and by combinations of these techniques. The increased diffraction grating element spacing is generated during the fabrication of the diffraction grating by controlling the cutting tool that is cutting the grooves or controlling the laser beam, electron beam or ion beam that is exposing the resist layer, etc. It is also possible to vary this variation in grating spacing by applying a thermal gradient to the diffraction grating in much the same manner as is done in the crystal diffraction case.

Smither, Robert K. (Hinsdale, IL)

1984-01-01T23:59:59.000Z

348

Thermal neutron imaging in an active interrogation environment  

SciTech Connect (OSTI)

We have developed a thermal-neutron coded-aperture imager that reveals the locations of hydrogenous materials from which thermal neutrons are being emitted. This imaging detector can be combined with an accelerator to form an active interrogation system in which fast neutrons are produced in a heavy metal target by means of xcitation by high energy photons. The photo-induced neutrons can be either prompt or delayed, depending on whether neutronemitting fission products are generated. Provided that there are hydrogenous materials close to the target, some of the photo-induced neutrons slow down and emerge from the surface at thermal energies. These neutrons can be used to create images that show the location and shape of the thermalizing materials. Analysis of the temporal response of the neutron flux provides information about delayed neutrons from induced fission if there are fissionable materials in the target. The combination of imaging and time-of-flight discrimination helps to improve the signal-to-background ratio. It is also possible to interrogate the target with neutrons, for example using a D-T generator. In this case, an image can be obtained from hydrogenous material in a target without the presence of heavy metal. In addition, if fissionable material is present in the target, probing with fast neutrons can stimulate delayed neutrons from fission, and the imager can detect and locate the object of interest, using appropriate time gating. Operation of this sensitive detection equipment in the vicinity of an accelerator presents a number of challenges, because the accelerator emits electromagnetic interference as well as stray ionizing radiation, which can mask the signals of interest.

Vanier,P.E.; Forman, L., and Norman, D.R.

2009-03-10T23:59:59.000Z

349

Neutron Bragg-edge-imaging for strain mapping under in situ tensile loading  

SciTech Connect (OSTI)

Wavelength selective neutron radiography at a cold neutron reactor source was used to measure strain and determine (residual) stresses in a steel sample under plane stress conditions. We present a new technique that uses an energy-resolved neutron imaging system based on a double crystal monochromator and is equipped with a specially developed (in situ) biaxial load frame to perform Bragg edge based transmission imaging. The neutron imaging technique provides a viewing area of 7 cm by 7 cm with a spatial resolution on the order of {approx} 100 {mu}m. The stress-induced shifts of the Bragg edge corresponding to the (110) lattice plane were resolved spatially for a ferritic steel alloy A36 (ASTM international) sample. Furthermore it is demonstrated that results agree with comparative data obtained using neutron diffraction and resistance based strain-gauge rosettes.

Woracek, R. [University of Tennessee, CEE Department, 223 Perkins Hall, Knoxville, Tennessee 37996 (United States); Helmholtz Zentrum Berlin, Hahn Meitner Platz 1, D-14109 Berlin (Germany); Penumadu, D. [University of Tennessee, CEE Department, 223 Perkins Hall, Knoxville, Tennessee 37996 (United States); Kardjilov, N.; Hilger, A.; Strobl, M.; Wimpory, R. C.; Manke, I.; Banhart, J. [Helmholtz Zentrum Berlin, Hahn Meitner Platz 1, D-14109 Berlin (Germany)

2011-05-01T23:59:59.000Z

350

X-ray Diffraction (XRD) 1.0 What is X-ray Diffraction  

E-Print Network [OSTI]

X-ray Diffraction (XRD) · 1.0 What is X-ray Diffraction · 2.0 Basics of Crystallography · 3.0 Production of X-rays · 4.0 Applications of XRD · 5.0 Instrumental Sources of Error · 6.0 Conclusions #12 why the cleavage faces of crystals appear to reflect X-ray beams at certain angles of incidence (theta

Moeck, Peter

351

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

352

Research Highlights | ORNL Neutron Sciences  

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

Biotechnology & Energy Biotechnology & Energy Neutron Imaging Reveals Lithium Distribution in Lithium-Air Electrodes Published Work: "Anomalous Discharge Product Distribution in Lithium-Air Cathodes" Contact: Jagjit Nanda Theory meets experiment: structure-property relationships in an electrode material for solid-oxide fuel cells (2012) Published Work: "Unveiling structure-property relationships in Sr2Fe1.5Mo0.5O6-#, an electrode material for symmetric solid oxide fuel cells" Contact: Ana B. Munoz-Garcia ORNL researchers probe invisible vacancies in fuel cell materials (2012) Published Work: "Probing oxygen vacancy concentration and homogeneity in solid-oxide fuel-cell cathode materials on the subunit-cell level" Contact: Albina Borisevich Studying how a protein's dynamics can take down a killer

353

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

354

Phase-shifting point diffraction interferometer  

DOE Patents [OSTI]

Disclosed is a point diffraction interferometer for evaluating the quality of a test optic. In operation, the point diffraction interferometer includes a source of radiation, the test optic, a beam divider, a reference wave pinhole located at an image plane downstream from the test optic, and a detector for detecting an interference pattern produced between a reference wave emitted by the pinhole and a test wave emitted from the test optic. The beam divider produces separate reference and test beams which focus at different laterally separated positions on the image plane. The reference wave pinhole is placed at a region of high intensity (e.g., the focal point) for the reference beam. This allows reference wave to be produced at a relatively high intensity. Also, the beam divider may include elements for phase shifting one or both of the reference and test beams. 8 figs.

Medecki, H.

1998-11-10T23:59:59.000Z

355

QCD and Hard Diffraction at the LHC  

E-Print Network [OSTI]

As an introduction to QCD at the LHC I give an overview of QCD at the Tevatron, emphasizing the high Q^2 frontier which will be taken over by the LHC. After describing briefly the LHC detectors I discuss high mass diffraction, in particular central exclusive production of Higgs and vector boson pairs. I introduce the FP420 project to measure the scattered protons 420m downstream of ATLAS and CMS.

Michael G. Albrow

2005-09-26T23:59:59.000Z

356

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.

357

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).

358

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

359

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,...

360

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

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

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

362

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

363

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...

364

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...

365

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

366

Design and transformation of three dimensional pupils : diffractive and subwavelength  

E-Print Network [OSTI]

Three dimensional pupils are investigated in both diffractive and subwavelength regimes and in various applications to shape the flow of light. In diffractive regime, volume holograms are good candidates for pupils of ...

Gao, Hanhong

2014-01-01T23:59:59.000Z

367

Biological Imaging by Soft X-Ray Diffraction Microscopy  

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

Biological Imaging by Soft X-Ray Diffraction Microscopy Biological Imaging by Soft X-Ray Diffraction Microscopy Print Wednesday, 30 November 2005 00:00 Electron and x-ray...

368

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

369

Recent developments in position-sensitive neutron counting  

SciTech Connect (OSTI)

Continuing research on advanced methods of thermal neutron detection and position sensing with gas-filled counters was aimed at improving their performance and extending the limits of their applicability. High electron drift velocities obtained from measurements on gas mixtures containing CF/sub 4/ motivated us to evaluate the properties of /sup 3/He-CF/sub 4/ and Ar-CF/sub 4/ mixtures to show that these gases have the potential of improving the count rate capability, spatial resolution, and photon discrimination of neutron PSPCs (position-sensitive proportional counters) and fission counters. In support of the U.S. National Small-Angle Neutron Scattering (SANS) Facility we developed a large-area (65-cm x 65-cm) PSPC camera. RC position encoding was chosen for simplicity of construction, but since previous experience with this encoding method had been limited to smaller PSPCs (area < 25 cm x 25 cm), the main objective of this development was to show that RC encoding parameters and construction methods could be scaled up for larger area PSPCs. The use of the new counter gas mixtures enabled the development of position-sensitive transmission line fission counters (TLFCs) for neutron flux monitoring and a one-dimensional, curved PSPC for large-angle (130/sup 0/) neutron diffraction experiments. The main objective of these developments was to extend the capabilities of the LC-encoding method by mitigating the effects of interelectrode capacitance, and thereby increase the count rate capability.

Valentine, K.H.; Kopp, M.K.; Guerrant, G.C.; Harter, J.A.

1982-01-01T23:59:59.000Z

370

Method of collecting and processing electron diffraction data  

DOE Patents [OSTI]

A method of using electron diffraction to obtain PDFs from crystalline, nanocrystalline, and amorphous inorganic, organic, and organometallic compound.

Billinge, Simon; Farrow, Christopher; Gorelik, Tatiana E; Kanatzidis, Mercouri; Schmidt, Martin U

2014-12-30T23:59:59.000Z

371

Diffractive parton distributions: the role of the perturbative Pomeron  

E-Print Network [OSTI]

We consider the role of the perturbative Pomeron-to-parton splitting in the formation of the diffractive parton distributions.

Watt, G; Ryskin, M G

2007-01-01T23:59:59.000Z

372

Diffractive parton distributions: the role of the perturbative Pomeron  

E-Print Network [OSTI]

We consider the role of the perturbative Pomeron-to-parton splitting in the formation of the diffractive parton distributions.

G. Watt; A. D. Martin; M. G. Ryskin

2007-08-30T23:59:59.000Z

373

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

374

X-ray diffraction study of thermal stress relaxation in ZnO films deposited by magnetron sputtering  

E-Print Network [OSTI]

are in a high compressive stress state. In situ X-ray diffraction measurements inside a furnace revealed a relaxation of the as-grown stresses at temperatures which vary with the atmosphere in the furnace and change in many application domains such as ultraviolet detectors, light-emitting diodes, solar cells. As a II

375

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 0.16±0.02 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

376

Charm production in diffractive DIS and PHP at ZEUS  

E-Print Network [OSTI]

The ZEUS experiment has measured charm production in diffractive DIS and in photoproduction. The data are in agreement with perturbative QCD calculations based on various parameterisations of diffractive parton distribution functions. The results are consistent with QCD factorisation in diffractive DIS and direct photoproduction.

Isabell-Alissandra Melzer-Pellmann; for the ZEUS collaboration

2007-08-03T23:59:59.000Z

377

Nanoparticle-Enhanced Diffraction Gratings for Ultrasensitive Surface Plasmon Biosensing  

E-Print Network [OSTI]

Nanoparticle-Enhanced Diffraction Gratings for Ultrasensitive Surface Plasmon Biosensing Alastair W by the adsorption of gold nanoparticles onto gold diffraction gratings. An enhanced diffraction obtained in the grating to the localized surface plasmons in the gold nanoparticles. As a first example

378

Dr. Ashfia Huq | ORNL Neutron Sciences  

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

Ashfia Huq Ashfia Huq Dr. Ashfia Huq Instrument Scientist: POWGEN Education PhD in Physics, Stony Brook University, in Stony Brook, New York (May 2003) AB degree, Magna Cum Laude with majors in Physics and Computer Science, Mount Holyoke College, South Hadley, Massachusetts (May 1996) Description of Research My primary research interest is neutron and X-ray powder diffraction of condensed matter systems and materials for energy storage. Topics include battery materials, solid oxide fuel cell (SOFC) materials, hydrogen storage materials, catalysis, and magnetic and structural properties of strongly correlated electron systems such as geometrically frustrated magnets, superconductors, etc. Selected Publications Zhonghe Bi, Juan Pena-Martinez, Jung-Hyun Kim, Craig A. Bridges, Ashfia

379

Dr. Xiaoping Wang | ORNL Neutron Sciences  

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

Home › Contact Us › CV Home › Contact Us › CV Dr. Xiaoping Wang Instrument Scientist TOPAZ BL-12 Dr. Xiaoping Wang received his Ph.D. degree in inorganic chemistry from Texas A&M University in 1998, where he did his graduate work with Professor F. Albert Cotton. He then undertook postdoctoral research in neutron crystallography at Argonne National Laboratory. He was the director for crystallographic computing in the Laboratory for Molecular Structure and Bonding at Texas A&M University from December 2001 to May 2006; the director of X-Ray Diffraction Laboratory at University of North Texas from June 2006 to July 2008, and has been appointed as adjunct professor in the chemistry department. Dr. Wang is currently an instrument scientist co-responsible for the TOPAZ single crystal diffractometer (SNS

380

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

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

Texture analysis of silicon with an heterogeneous morphology used for the photovoltaic conversion by neutron diffraction  

E-Print Network [OSTI]

603 Texture analysis of silicon with an heterogeneous morphology used for the photovoltaic.10F - 61.14F 1. Introduction. In order to lower the production cost of solar cells, the Research perpendicularly to growth axis, which led to photovoltaic efficiency q ~ 11 % under AM1 conditions, starting

Paris-Sud XI, Université de

382

Neutron diffraction of. cap alpha. ,. beta. and. gamma. cyclodextrins: hydrogen bonding patterns  

SciTech Connect (OSTI)

Cyclodextrins (CD's) are torus-shaped molecules composed of six (..cap alpha..), seven (..beta..) or eight (..gamma..) (1 ..-->.. 4) linked glucoses. ..cap alpha..-CD has been shown to have two different structures with well-defined hydrogen bonds, one tense and the other relaxed. An induced-fit-like mechanism for ..cap alpha..-CD complex formation has been proposed. Circular hydrogen bond networks have also been found for ..cap alpha..-CD due to the energetically favored cooperative effect. ..beta..-CD with a disordered water structure possesses an unusual flip-flop hydrogen bonding system of the type O-H H-O representing an equilibrium between two states; O-H O reversible H-O. ..gamma..-CD with a disordered water structure similar to ..beta..-CD also possesses the flip-flop hydrogen bond. This study demonstrates that hydrogen bonds are operative in disordered systems and display dynamics even in the solid state.

Hingerty, B.E.; Klar, B.; Hardgrove, G.; Betzel, C.; Saenger, W.

1983-01-01T23:59:59.000Z

383

Cold drawn steel wires--processing, residual stresses and ductility Part II: Synchrotron and neutron diffraction  

E-Print Network [OSTI]

Cold drawn steel wires--processing, residual stresses and ductility Part II: Synchrotron Received in final form 29 September 2005 ABSTRACT Cold drawing of steel wires leads to an increase proposed that cold drawing would induce a phase transformation of the steel, possibly a martensitic

384

A low-temperature neutron diffraction study of Mn12-acetate  

Science Journals Connector (OSTI)

The low-temperature structure of the title dodecanuclear mixed-valence manganese carboxylate, [Mn12O12(CD3COO)16(H2O)4]·2CD3COOH·4H2O, is similar to the room-temperature structure, differing by a small change in the configuration of one of the coordinated acetate groups, related to additional hydrogen bonding.

Langan, P.

2001-08-09T23:59:59.000Z

385

Characterization of Li-ion Batteries using Neutron Diffraction and Infrared Imaging Techniques  

Broader source: Energy.gov [DOE]

2011 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation

386

Neutron Scattering and Diffraction Studies of Fluids and Fluid-Solid Interactions  

Science Journals Connector (OSTI)

...biopolymers, including proteins) and low-dimensional...scattering in partially disordered materials such as fluids...r-parameter is an ensemble average over the thermally...structure corresponds to the ensemble average for all molecules...volume) arises from an ensemble of snap shot images...

David R. Cole; Kenneth W. Herwig; Eugene Mamontov; John Z. Larese

387

Neutron powder diffraction of metal-organic frameworks for hydrogen storage  

Science Journals Connector (OSTI)

We review recent structural studies that we have undertaken aimed at elucidating the fundamental properties of metal-organic framework materials and their interactions with hydrogen. We have shown that exposin...

Craig M. Brown; Yun Liu; Dan A. Neumann

2008-10-01T23:59:59.000Z

388

Exclusive Diffractive Processes within the Dipole Picture  

E-Print Network [OSTI]

We discuss two different models for the impact parameter dependent dipole cross section: one based on DGLAP evolution and the other inspired by the Balitsky-Kovchegov equation. The parameters are determined from fits to data on the total gamma* p cross section measured at HERA. The impact parameter dependent saturation scale is extracted. Predictions are then confronted with HERA data on exclusive diffractive vector meson production and deeply virtual Compton scattering. Finally, predictions are given for the cross sections of exclusive photoproduced J/psi and Upsilon mesons, and Z^0 bosons, expected at the Tevatron and LHC.

G. Watt

2008-07-28T23:59:59.000Z

389

Exclusive Diffractive Processes within the Dipole Picture  

E-Print Network [OSTI]

We discuss two different models for the impact parameter dependent dipole cross section: one based on DGLAP evolution and the other inspired by the Balitsky-Kovchegov equation. The parameters are determined from fits to data on the total gamma* p cross section measured at HERA. The impact parameter dependent saturation scale is extracted. Predictions are then confronted with HERA data on exclusive diffractive vector meson production and deeply virtual Compton scattering. Finally, predictions are given for the cross sections of exclusive photoproduced J/psi and Upsilon mesons, and Z^0 bosons, expected at the Tevatron and LHC.

Watt, G

2008-01-01T23:59:59.000Z

390

Lessons from LHC elastic and diffractive data  

E-Print Network [OSTI]

In the light of LHC data, we discuss the global description of all high energy elastic and diffractive data, using a one-pomeron model, but including multi-pomeron interactions. The LHC data indicate the need of a $k_t(s)$ behaviour, where $k_t$ is the gluon transverse momentum along the partonic ladder structure which describes the pomeron. We also discuss tensions in the data, as well as the $t$ dependence of the slope of $d\\sigma_{el}/dt$ in the small $t$ domain.

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

2014-10-13T23:59:59.000Z

391

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

392

Optical-diffraction method for determining crystal orientation  

DOE Patents [OSTI]

Disclosed is an optical diffraction technique for characterizing the three-dimensional orientation of a crystal sample. An arbitrary surface of the crystal sample is texture etched so as to generate a pseudo-periodic diffraction grating on the surface. A laser light beam is then directed onto the etched surface, and the reflected light forms a farfield diffraction pattern in reflection. Parameters of the diffraction pattern, such as the geometry and angular dispersion of the diffracted beam are then related to grating shape of the etched surface which is in turn related to crystal orientation. This technique may be used for examining polycrystalline silicon for use in solar cells.

Sopori, B.L.

1982-05-07T23:59:59.000Z

393

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

394

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.

395

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

396

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

397

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

398

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

399

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

400

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

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

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 scattering—with the notable exception of a suitable accelerator facility—are at hand.

Roger W. Finlay

1985-01-01T23:59:59.000Z

402

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

403

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...

404

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

405

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/

406

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,"

407

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

408

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

409

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

410

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

411

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

412

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

413

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

414

Scattering of Slow Neutrons by a Liquid  

Science Journals Connector (OSTI)

The differential cross section for coherent scattering of thermal neutrons by a liquid is given in general by the Fourier transform of a time-displaced radial density function. It is suggested here that, to an adequate degree of approximation, this time-displaced function can be expressed as a convolution of the ordinary radial density function with a self-diffusion function describing the wandering of an atom from an arbitrary initial position. The neutron scattering cross section then becomes the product of the Fourier transforms of these two functions. One of the transforms is the differential cross section for x-ray scattering and describes interference effects, the other governs the energy changes upon scattering. In this development the scatterer can be treated either quantum mechanically or classically. Recoil effects are not provided by the classical treatment, but this is a significant deficiency only in liquids of low atomic weight. Several models for calculating the self-diffusion function are considered, and from these it is suggested that a Gaussian function with a time-dependent width is a reasonable approximation for the case of a simple liquid. The principal features of the width are deduced. Quantization of the scatterer effects the width at small times. At large times the width depends only on the coefficient of self-diffusion of the liquid, and inelastic scattering is suggested as a means of determining this coefficient, as well as other features of atomic movement. The accuracy of the static approximation for determining liquid structures by neutron diffraction is assessed by considering the typical case of liquid lead near its melting point, and is found to be moderately good. The extension of the entire formalism to the case of polyatomic liquids is outlined.

George H. Vineyard

1958-06-01T23:59:59.000Z

415

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. Wölwitsch

1991-11-01T23:59:59.000Z

416

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, ± 10 meV the applications are principally quasielastic scattering and tunneling spectroscopy. The second range, 0–1000 meV covers the regions of vibrational spectroscopy and magnetic excitations. The highest range above 1000 meV 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

417

JOURNAL DE PHYSIQUE ColZoque C8, suppl6ment au n08, Tome 41, aoGt 1980, page C8-595 DENSITY, COMPRESSIBILITY, SPECIFIC HEAT AND DIFFRACTION DATA OF LITHIUM-MAGNESIUM ALLOYS  

E-Print Network [OSTI]

, COMPRESSIBILITY, SPECIFIC HEAT AND DIFFRACTION DATA OF LITHIUM-MAGNESIUM ALLOYS H. Ruppersberg, 3. Saar, W deviation from linear behaviour. The excess specific heat is Larger for the liquid than for the solid phase. Introduction We study lithium alloys because the isotope 7 ~ ihas a negative neutron-scattering amplitude

Paris-Sud XI, Université de

418

Neutron and x-ray scattering studies of the metallurgical condition and residual stresses in Weldalite welds  

SciTech Connect (OSTI)

Weldalite is a lithium-containing aluminum alloy which is being considered for aerospace applications because its favorable strength-to-weight ratio. Successful welding of this alloy depends on the control of the metallurgical condition and residual stresses in the heat affected zone. Neutron and x-ray scattering methods of residual stress measurement were applied to plasma arc welds made in aluminum-lithium alloy test panels as part of an evaluation of materials for use in welded structures. In the course of these studies discrepancies between x-ray and neutron results from the heat affected zone (HAZ) of the weld were found. Texture changes and recovery from the cold work, indicated in peak widths, were found in the HAZ as well. The consideration of x-ray and neutron results leads to the conclusion that there is a change in solute composition which modifies the d-spacings in the HAZ which affects the neutron diffraction determination of residual stresses. The composition changes give the appearance of significant compressive strains in the HAZ. This effect and sharp gradients in the texture give severe anomalies in the neutron measurement of residual stress. The use of combined x-ray and neutron techniques and the solution to the minimizing of the neutron diffraction anomalies are discussed.

Spooner, S. [Oak Ridge National Lab., TN (United States); Pardue, E.B.S. [Technology for Energy Corp., Knoxville, TN (United States)

1995-12-31T23:59:59.000Z

419

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

420

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

Note: This page contains sample records for the topic "neutron diffraction reveals" 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 - 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

422

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

423

Introduction to Neutron and X-Ray Scattering  

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

Scattering Studies of Thin Scattering Studies of Thin Polymer Films Introduction to Neutron and X-Ray Scattering Sunil K. Sinha UCSD/LANL Acknowledgements: Prof. R.Pynn( Indiana U.) Prof. M.Tolan (U. Dortmund) Wilhelm Conrad Röntgen 1845-1923 1895: Discovery of X-Rays 1901 W. C. Röntgen in Physics for the discovery of x-rays. 1914 M. von Laue in Physics for x-ray diffraction from crystals. 1915 W. H. Bragg and W. L. Bragg in Physics for crystal structure determination. 1917 C. G. Barkla in Physics for characteristic radiation of elements. 1924 K. M. G. Siegbahn in Physics for x-ray spectroscopy. 1927 A. H. Compton in Physics for scattering of x-rays by electrons. 1936 P. Debye in Chemistry for diffraction of x-rays and electrons in gases.

424

Apparent Neutron Emissions from Polyethylene Capsules during Neutron Activation and Delayed Neutron Counting  

Science Journals Connector (OSTI)

At Imperial College uranium is determined at very low levels in environmental samples by delayed neutron counting. High density polyethylene capsules are used ... transfer system, from the reactor, to the neutron

R. Benzing; N. M. Baghini; B. A. Bennett…

2000-05-01T23:59:59.000Z

425

BEAMLINE 11-3 Materials Diffraction  

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

3 3 CURRENT STATUS: Open SUPPORTED TECHNIQUES: X-ray scattering Thin film diffraction MAIN SCIENTIFIC DISCIPLINES: Materials / Environmental / Biology % TIME GENERAL USE: 100% SCHEDULING: Proposal Submittal and Scheduling Procedures Current SPEAR and Beam Line Schedules SOURCE: 26-pole, 2.0-Tesla ID Side Station BEAM LINE SPECIFICATIONS: energy range resolution DE/E spot size flux angular acceptance focused 12735 eV ~5 x 10-4 3.1 x 0.15 mm Usable 0.15 x 0.15 mm OPTICS: Single-crystal Si, Rh-coated - vertically focusing mirror MONOCHROMATOR: Bent cube-root I_beam Si(311), Side deflecting Monochromator Crystal Glitch Library Crystal changes need to be scheduled and coordinated in advance with BL support staff. ABSORPTION: INSTRUMENTATION: Standard detector: MAR345 Imaging Plate - 345 mm

426

Biology and Soft Matter Division | Neutron Science | ORNL  

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

Biology and Soft Matter Division Biology and Soft Matter Division SHARE Biology and Soft Matter Division BSMD Director Paul Langan The Biology and Soft Matter Division (BSMD) operates an external user program for biological and soft matter research using neutron techniques at SNS and HFIR. Division personnel enable the research initiated by external users by acting as instrument responsible scientists and local contacts on a range of different beam lines. BSMD works closely with the Center for Structural Molecular Biology. Diffraction, small-angle scattering, and reflectometry are ideal methods for studying structure and organization from the atomic to the micron length scales, and neutron spectroscopic methods characterize self and collective motions from picosecond to microsecond timescales. These

427

Geant4 based simulations for novel neutron detector development  

E-Print Network [OSTI]

A Geant4-based Python/C++ simulation and coding framework, which has been developed and used in order to aid the R&D efforts for thermal neutron detectors at neutron scattering facilities, is described. Built upon configurable geometry and generator modules, it integrates a general purpose object oriented output file format with meta-data, developed in order to facilitate a faster turn-around time when setting up and analysing simulations. Also discussed are the extensions to Geant4 which have been implemented in order to include the effects of low-energy phenomena such as Bragg diffraction in the polycrystalline support materials of the detector. Finally, an example application of the framework is briefly shown.

Thomas Kittelmann; Irina Stefanescu; Kalliopi Kanaki; Mirko Boin; Richard Hall-Wilton; Karl Zeitelhack

2013-11-05T23:59:59.000Z

428

Geant4 based simulations for novel neutron detector development  

E-Print Network [OSTI]

A Geant4-based Python/C++ simulation and coding framework, which has been developed and used in order to aid the R&D efforts for thermal neutron detectors at neutron scattering facilities, is described. Built upon configurable geometry and generator modules, it integrates a general purpose object oriented output file format with meta-data, developed in order to facilitate a faster turn-around time when setting up and analysing simulations. Also discussed are the extensions to Geant4 which have been implemented in order to include the effects of low-energy phenomena such as Bragg diffraction in the polycrystalline support materials of the detector. Finally, an example application of the framework is briefly shown.

Kittelmann, Thomas; Kanaki, Kalliopi; Boin, Mirko; Hall-Wilton, Richard; Zeitelhack, Karl

2013-01-01T23:59:59.000Z

429

Diffraction and coherence in breast ultrasound tomography: a study with a toroidal array  

SciTech Connect (OSTI)

Ultrasound is commonly used as an adjunct to mammography for diagnostic evaluation of suspicions arising from breast cancer screening. As an alternative to conventional sonography that uses hand-held transducers, toroidal array probes that encircle the breast immersed in a water bath have been investigated for ultrasound tomography. In this paper, two sets of experiments performed with a prototype ultrasound scanner on a phantom and a human breast in vivo are used to investigate the effects of diffraction and coherence in ultrasound tomography. Reconstructions obtained with transmission diffraction tomography (TDT) are compared with conventional reflection imaging and computerized ultrasound tomography showing a substantial improvement. The in vivo tests demonstrate that TDT can image the complex boundary of a cancer mass and suggest that it can reveal the anatomy of milk ducts and Cooper's ligaments.

Huang, Lianjie [Los Alamos National Laboratory; Simonetti, Francesco [IMPERIAL COLL.; Duric, Neb [KCI; Littrup, Peter [KCI

2008-01-01T23:59:59.000Z

430

SciTech Connect: 2010 Neutron Review: ORNL Neutron Sciences Progress...  

Office of Scientific and Technical Information (OSTI)

117; GREENHOUSE GASES; HEAVY ION ACCELERATORS; HELIUM 3; HFIR REACTOR; IRON; JINR; MAGNETIC FIELDS; NEUTRON DETECTORS; NEUTRON SOURCES; NEUTRONS; ORNL; RELIABILITY;...

431

Neutron Absorbing Alloys  

DOE Patents [OSTI]

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

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

2004-05-04T23:59:59.000Z

432

Proton-Neutron Scattering  

Science Journals Connector (OSTI)

Using Glauber multiple-scattering theory, the missing-mass spectrum for protons scattered off a deuterium target is computed. The relatively clean separation of the single- and double-scattering peaks offers the possibility of determining the high-energy proton-neutron differential cross section.

N. Straumann and C. Wilkin

1970-03-02T23:59:59.000Z

433

Optimization of neutron source  

SciTech Connect (OSTI)

I consider here the optimization of the two component neutron source, allowing beam species and energy to vary. A simple model is developed, based on the earlier publications, that permits the optimum to be obtained simply. The two component plasma, with one species of hot ion (D{sup +} or T{sup +}) and the complementary species of cold ion, is easy to analyze in the case of a spatially uniform cold plasma, as to good approximation the total number of hot ions is important but not their spatial distribution. Consequently, the optimization can ignore spatial effects. The problem of a plasma with both types of hot ions and cold ions is rather more difficult, as the neutron production by hot-hot interactions is sensitive to their spatial distributions. Consequently, consideration of this problem will be delayed to a future memorandum. The basic model is that used in the published articles on the two-component, beam-plasma mirror source. I integrate the Fokker-Planck equation analytically, obtaining good agreement with previous numerical results. This simplifies the optimization, by providing a functional form for the neutron production. The primary result is expressed in terms of the power efficiency: watts of neutrons/watts of primary power. The latter includes the positive ion neutralization efficiency. At 150 keV, the present model obtains an efficiency of 0.66%, compared with 0.53% of the earlier calculation.

Hooper, E.B.

1993-11-09T23:59:59.000Z

434

Solid state neutron detector array  

DOE Patents [OSTI]

A neutron detector array is capable of measuring a wide range of neutron fluxes. The array includes multiple semiconductor neutron detectors. Each detector has a semiconductor active region that is resistant to radiation damage. In one embodiment, the array preferably has a relatively small size, making it possible to place the array in confined locations. The ability of the array to detect a wide range of neutron fluxes is highly advantageous for many applications such as detecting neutron flux during start up, ramp up and full power of nuclear reactors.

Seidel, John G. (Pittsburgh, PA); Ruddy, Frank H. (Monroeville, PA); Brandt, Charles D. (Mount Lebanon, PA); Dulloo, Abdul R. (Pittsburgh, PA); Lott, Randy G. (Pittsburgh, PA); Sirianni, Ernest (Monroeville, PA); Wilson, Randall O. (Greensburg, PA)

1999-01-01T23:59:59.000Z

435

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

436

Dose-equivalent neutron dosimeter  

DOE Patents [OSTI]

A neutron dosimeter is disclosed which provides a single measurement indicating the amount of potential biological damage resulting from the neutron exposure of the wearer, for a wide range of neutron energies. The dosimeter includes a detecting sheet of track etch detecting material such as a carbonate plastic, for detecting higher energy neutrons, and a radiator layer contaning conversion material such as /sup 6/Li and /sup 10/B lying adjacent to the detecting sheet for converting moderate energy neutrons to alpha particles that produce tracks in the adjacent detecting sheet.

Griffith, R.V.; Hankins, D.E.; Tomasino, L.; Gomaa, M.A.M.

1981-01-07T23:59:59.000Z

437

Definition: X-Ray Diffraction (XRD) | Open Energy Information  

Open Energy Info (EERE)

X-Ray Diffraction (XRD) X-Ray Diffraction (XRD) Jump to: navigation, search Dictionary.png X-Ray Diffraction (XRD) X-Ray Diffraction (XRD) is a laboratory-based technique commonly used for identification of crystalline materials and analysis of unit cell dimensions. One of two primary types of XRD analysis (X-ray powder diffraction and single-crystal XRD) is commonly applied to samples to obtain specific information about the crystalline material under investigation. X-ray powder diffraction is widely used in geology, environmental science, material science, and engineering to rapidly identify unknown crystalline substances (typically in less than 20 minutes). A pure, finely ground, and homogenized sample is required for determination of the bulk composition. Additional uses include detailed

438

X-Ray Diffraction (XRD) | Open Energy Information  

Open Energy Info (EERE)

X-Ray Diffraction (XRD) X-Ray Diffraction (XRD) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: X-Ray Diffraction (XRD) Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Lab Analysis Techniques Exploration Sub Group: Rock Lab Analysis Parent Exploration Technique: Rock Lab Analysis Information Provided by Technique Lithology: Rapid and unambiguous identification of unknown minerals.[1] Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png X-Ray Diffraction (XRD): X-Ray Diffraction (XRD) is a laboratory-based technique commonly used for identification of crystalline materials and analysis of unit cell dimensions. One of two primary types of XRD analysis (X-ray powder diffraction and single-crystal XRD) is commonly applied to samples to

439

Portable X-Ray Diffraction (XRD) | Open Energy Information  

Open Energy Info (EERE)

Portable X-Ray Diffraction (XRD) Portable X-Ray Diffraction (XRD) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Portable X-Ray Diffraction (XRD) Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Field Techniques Exploration Sub Group: Data Collection and Mapping Parent Exploration Technique: Data Collection and Mapping Information Provided by Technique Lithology: Rapid and unambiguous identification of unknown minerals.[1] Stratigraphic/Structural: Hydrological: Thermal: Dictionary.png Portable X-Ray Diffraction (XRD): Portable X-Ray Diffraction (XRD) is a field-based technique that can be used for identification of crystalline materials and analysis of unit cell dimensions. Portable XRD analysis is similar to X-ray powder diffraction,

440

Ethylene on graphite: A low-energy electron-diffraction study  

Science Journals Connector (OSTI)

Several phases of monolayer ethylene on single-crystal graphite have been studied using low-energy electron diffraction. We have determined the unit cell and orientation with respect to the graphite substrate of the orientationally ordered and disordered low-density phases (OLD and DLD), in which molecules are believed to lie with the C?C bond parallel to the surface. Based on published neutron-scattering results, we propose a basis for the OLD phase. The low-coverage DLD phase, believed to undergo a continuous melting transition at 70 K, appears to be a higher-order commensurate structure at this transition. We also report observations of ordered and disordered high-density phases in which molecules stand on end, in both commensurate and incommensurate epitaxies.

V. L. Eden and S. C. Fain; Jr.

1991-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

Ghost Diffraction: Causal Explanation via Correlated Trajectory Calculations  

E-Print Network [OSTI]

We use trajectory calculations to successfully explain two-photon "ghost" diffraction, a phenomenon previously explained via quantum mechanical entanglement. The diffraction patterns are accumulated one photon pair at a time. The calculations are based on initial correlation of the trajectories in the crystal source and a trajectory-wave ordering interaction with a variant generator inherent in its structure. Details are presented in comparison with ordinary diffraction calculated with the same trajectory model.

Bill Dalton

2001-02-22T23:59:59.000Z

442

SNS | Spallation Neutron Source | ORNL  

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

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

443

Broadband Diffractive Optics for Enhancing the Efficiency of Solar Cells  

Science Journals Connector (OSTI)

We propose a broadband diffractive optics based spectrum splitting approach to enhance the efficiency of solar cells. Numerical simulations indicate ~27% and ~45% increase in output...

Menon, Rajesh; Wang, Peng; Mohammed, Nabil

444

Space Groups: A primer on topics significant for powder diffraction  

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

Space Groups: A primer on topics significant for powder diffraction Presentation Goal Introduce symmetry concepts important for Rietveld analysis, particularly of inorganic...

445

Diffraction: Enhanced Light Absorption of Solar Cells and Photodetecto...  

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

Materials Advanced Materials Find More Like This Return to Search Diffraction: Enhanced Light Absorption of Solar Cells and Photodetectors Sandia National Laboratories Contact...

446

Self-terminating diffraction gates femtosecond X-ray nanocrystallograp...  

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

Self-terminating diffraction gates femtosecond X-ray nanocrystallography measurements Authors: Barty, A., Caleman, C., Aquila, A., Timneanu, N., Lomb, L., White, T. A., Andreasson,...

447

Diffraction Phase Cytometry: blood on a CD-ROM  

Science Journals Connector (OSTI)

We demonstrate Diffraction Phase Cytometry (DPC) as a single shot, full-field, high throughput quantitative phase imaging modality, dedicated to analyzing whole blood smears. Utilizing...

Mir, Mustafa; Wang, Zhuo; Tangella, Krishnarao; Popescu, Gabriel

2009-01-01T23:59:59.000Z

448

Electron Diffraction from a Cold Atom Electron Source  

Science Journals Connector (OSTI)

We present single-shot nanosecond and picosecond electron diffraction measurements from gold and graphene using ultracold electrons generated by photoionisation of laser cooled atoms.

Speirs, Rory W; Thompson, Daniel J; Murphy, Dene; Sparkes, Ben M; Scholten, Rob E

449

Computed phase equilibria for burnable neutron absorbing materials for advanced pressurized heavy water reactors  

Science Journals Connector (OSTI)

Burnable neutron absorbing materials are expected to be an integral part of the new fuel design for the Advanced CANDU®[CANDU is as a registered trademark of Atomic Energy of Canada Limited.] Reactor. The neutron absorbing material is composed of gadolinia and dysprosia dissolved in an inert cubic-fluorite yttria-stabilized zirconia matrix. A thermodynamic model based on Gibbs energy minimization has been created to provide estimated phase equilibria as a function of composition and temperature. This work includes some supporting experimental studies involving X-ray diffraction.

E.C. Corcoran; B.J. Lewis; W.T. Thompson; J. Hood; F. Akbari; Z. He; P. Reid

2009-01-01T23:59:59.000Z

450

Neutron and X-Ray Studies of Advanced Materials V: CENTENNIAL  

SciTech Connect (OSTI)

In 2012 the diffraction community will celebrate 100 years since the prediction of X-ray diffraction by M. Laue, and following his suggestion the first beautiful diffraction experiment by W. Friedrich and P. Knipping. The significance of techniques based on the analysis of the diffraction of X-rays, neutrons, electrons and Mossbauer photons discovered later, has continued to increase in the past 100 years. The aim of this symposium is to provide a forum for discussion of using state-of-the-art neutron and X-ray scattering techniques for probing advanced materials. These techniques have been widely used to characterize materials structures across all length scales, from atomic to nano, meso, and macroscopic scales. With the development of sample environments, in-situ experiments, e.g., at temperatures and applied mechanical load, are becoming routine. The development of ultra-brilliant third-generation synchrotron X-ray sources, together with advances in X-ray optics, has created intense X-ray microbeams, which provide the best opportunities for in-depth understanding of mechanical behavior in a broad spectrum of materials. Important applications include ultra-sensitive elemental detection by X-ray fluorescence/absorption and microdiffraction to identify phase and strain with submicrometer spatial resolution. X-ray microdiffraction is a particularly exciting application compared with alternative probes of crystalline structure, orientation and strain. X-ray microdiffraction is non-destructive with good strain resolution, competitive or superior spatial resolution in thick samples, and with the ability to probe below the sample surface. Advances in neutron sources and instrumentation also bring new opportunities in neutron scattering research. In addition to characterizing the structures, neutrons are also a great tool for elucidating the dynamics of materials. Because neutrons are highly penetrating, neutrons have been used to map stress in engineering systems. Neutrons have also played a vital role in our understanding of the magnetism and magnetic properties. Specialized instruments have been built to gain physical insights of the fundamental mechanisms governing phase transformation and mechanical behaviors of materials. The application of those techniques, in combination with theoretical simulations and numerical modeling, will lead to major breakthroughs in materials science in the foreseeable future that will contribute to the development of materials technology and industrial innovation.

Spanos, George

2012-05-01T23:59:59.000Z

451

Neutron drops and neutron pairing energy  

Science Journals Connector (OSTI)

The ground state energy of a six-neutron drop is computed with variational and Green’s function Monte Carlo methods using the Argonne v18 two-nucleon and the Urbana three-nucleon potentials. Combined with earlier results from investigations of the drops 8n and 7n, this energy gives a 1p-shell pairing energy of (1.8±0.4) MeV. The generalized Skyrme effective interaction discussed in the earlier work is applied to these nuclei by calculating, for the open-shell drops 7n and 6n, the matrix elements of the Skyrme t matrix directly for the states involved. The pairing energy obtained is 1.50 MeV, in reasonable agreement with the accurate calculations.

A. Smerzi; D. G. Ravenhall; V. R. Pandharipande

1997-11-01T23:59:59.000Z

452

Observation of Neutron Skyshine from an Accelerator Based Neutron Source  

SciTech Connect (OSTI)

A key feature of neutron based interrogation systems is the need for adequate provision of shielding around the facility. Accelerator facilities adapted for fast neutron generation are not necessarily suitably equipped to ensure complete containment of the vast quantity of neutrons generated, typically >10{sup 11} n{center_dot}s{sup -1}. Simulating the neutron leakage from a facility is not a simple exercise since the energy and directional distribution can only be approximated. Although adequate horizontal, planar shielding provision is made for a neutron generator facility, it is sometimes the case that vertical shielding is minimized, due to structural and economic constraints. It is further justified by assuming the atmosphere above a facility functions as an adequate radiation shield. It has become apparent that multiple neutron scattering within the atmosphere can result in a measurable dose of neutrons reaching ground level some distance from a facility, an effect commonly known as skyshine. This paper describes a neutron detection system developed to monitor neutrons detected several hundred metres from a neutron source due to the effect of skyshine.

Franklyn, C. B. [Radiation Science Department, Necsa, PO Box 582, Pretoria 0001 (South Africa)

2011-12-13T23:59:59.000Z

453

Search for neutron - mirror neutron oscillations in a laboratory experiment with ultracold neutrons  

E-Print Network [OSTI]

Mirror matter is considered as a candidate for dark matter. In connection with this an experimental search for neutron - mirror neutron (nn') transitions has been carried out using storage of ultracold neutrons in a trap with different magnetic fields. As a result, a new limit for the neutron - mirror neutron oscillation time has been obtained, tau_osc >= 448 s (90% C.L.), assuming that there is no mirror magnetic field larger than 100 nT. Besides a first attempt to obtain some restriction for mirror magnetic field has been done.

A. P. Serebrov; E. B. Aleksandrov; N. A. Dovator; S. P. Dmitriev; A. K. Fomin; P. Geltenbort; A. G. Kharitonov; I. A. Krasnoschekova; M. S. Lasakov; A. N. Murashkin; G. E. Shmelev; V. E. Varlamov; A. V. Vassiljev; O. M. Zherebtsov; O. Zimmer

2008-09-29T23:59:59.000Z

454

A Polarized Neutron Scattering Study of the Normal Phase in YBa2Cu3O6.95  

Science Journals Connector (OSTI)

Polarized neutron scattering with polarization analysis has revealed negligible magnetic scattering up to 30 meV in the normal...2Cu3O6.95 indicating the absence of local moments.

T. J. Smith; K. H. Andersen; U. Beck; H. Capellmann…

1999-02-01T23:59:59.000Z

455

13 - X-ray and Neutron Scattering  

Science Journals Connector (OSTI)

Abstract This chapter describes the use of neutrons and X-rays as probes in the study of structural and dynamic properties of metallic materials. Crystalline materials are characterized by their diffraction peaks related to their average crystallographic structure. In real crystals, locally displaced atoms and chemically (or isotopically for neutrons) different species may lead not only to changes of peak shapes and positions, but also to additional (diffuse) scattering between Bragg peak, including scattering around the primary beam (small-angle scattering). All these features can be used to extract information about the state of a sample, its compositional and structural variations on a scale depending on the scattering, in static and time-resolved kinetic studies. Energy-resolved scattering also offers an insight into solid-state dynamics on a microscopic scale. Some of the most important methods will be described and illustrated by instructive examples. The presentation offers a combined view of neutron and X-ray scattering, with the necessary simplifications dictated by space limitations. The special properties of thermal neutrons and of hard X-rays (now widely available at synchrotron radiation sources), their mutual combination, and combinations with other methods, in particular electron microscopy, offer ample opportunity to better understand and control materials properties. After a brief introduction to scattering from real crystals and some general ideas about long-range strains and Bragg peaks, the vicinity of Bragg peaks (displacement scattering at large scattering angles), the scattering far away from Bragg peaks (chemical heterogeneities, short-range order), and, in greater detail, small-angle scattering (which is not sensitive to the extent of crystallinity, but to nanoscale variations of chemical composition and of magnetization, precipitation) will be described, along with classical and more recent applications related to short-range ordering and precipitation in bulk and nanostructured alloys. Some other fields are only briefly addressed (grazing-incidence studies of surfaces, radiography, absorption spectroscopies, coherent X-rays). The final section offers some information on the influence of defects on lattice dynamics and on (slow) diffusive motion in materials.

Gernot Kostorz

2014-01-01T23:59:59.000Z

456

First neutron generation in the BINP accelerator based neutron source  

Science Journals Connector (OSTI)

Pilot innovative facility for neutron capture therapy was built at Budker Institute of Nuclear Physics, Novosibirsk. This facility is based on a compact vacuum insulation tandem accelerator designed to produce proton current up to 10 mA. Epithermal neutrons are proposed to be generated by 1.915 MeV protons bombarding a lithium target using 7Li(p,n)7Be threshold reaction. The results of the first experiments on neutron generation are reported and discussed.

B. Bayanov; A. Burdakov; V. Chudaev; A. Ivanov; S. Konstantinov; A. Kuznetsov; A. Makarov; G. Malyshkin; K. Mekler; I. Sorokin; Yu. Sulyaev; S. Taskaev

2009-01-01T23:59:59.000Z

457

Protein crystallography with spallation neutrons: the user facility at Los Alamos Neutron Science Center  

Science Journals Connector (OSTI)

The protein crystallography user facility at the neutron spallation source run by Los Alamos Neutron Science Center is described.

Langan, P.

2004-01-17T23:59:59.000Z

458

Neutron electric polarizability  

E-Print Network [OSTI]

We use the background field method to extract the "connected" piece of the neutron electric polarizability. We present results for quenched simulations using both clover and Wilson fermions and discuss our experience in extracting the mass shifts and the challenges we encountered when we lowered the quark mass. For the neutron we find that as the pion mass is lowered below $500\\MeV$, the polarizability starts rising in agreement with predictions from chiral perturbation theory. For our lowest pion mass, $m_\\pi=320\\MeV$, we find that $\\alpha_n = 3.8(1.3)\\times 10^{-4}\\fm^3$, which is still only one third of the experimental value. We also present results for the neutral pion; we find that its polarizability turns negative for pion masses smaller than $500\\MeV$ which is puzzling.

Andrei Alexandru; Frank X. Lee

2009-11-13T23:59:59.000Z

459

Artificial Production of Neutrons  

Science Journals Connector (OSTI)

A porcelain vacuum tube capable of producing currents of positive ions up to 30 microamperes and with energies up to 106 electron-volts has been constructed and used for artificial disintegration experiments. Neutrons have been produced by bombarding beryllium with helium ions, and by bombarding lithium and beryllium with the ions of the heavy isotope of hydrogen. The curve obtained for the efficiency of production of neutrons by helium ions as a function of voltage is in agreement with the curve obtained by a downward extrapolation of curves known from work with polonium ?-particles. The present paper is mainly a discussion of the apparatus and methods of measurement, since brief reports of the results have already been presented.

H. R. Crane; C. C. Lauritsen; A. Soltan

1934-04-15T23:59:59.000Z

460

Coherence of neutron fields  

Science Journals Connector (OSTI)

Glauber's definition of quantum coherence is used for neutron fields under the assumption that the complete occupation number space is a direct product of Fermi subspaces. As a result, completely coherent microfields are obtained which define a density operator in full analogy to Glauber's P representation of boson fields. For better physical significance, a transformation from the P representation to a momentum representation is performed. It is proved that the second-order coherence function in this representation is equivalent to Wolf's second-order coherence function of a classical Dirac field. Finally, the results of the theory are used to calculate explicitly the second-order coherence function and the coherence time of an ideally collimated neutron beam.

E. Ledinegg and E. Schachinger

1983-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

Principal Component Analysis of X-ray Diffraction Patterns To Yield Morphological Classification of Brucite Particles  

Science Journals Connector (OSTI)

Principal Component Analysis of X-ray Diffraction Patterns To Yield Morphological Classification of Brucite Particles ... Finally, a comparison of the scanning electron microscopy images of the samples classified in each group revealed that in most of the cases a distinct morphology predominates within each group, which can be explained on the basis of the brucite growth mechanism. ... The increasing interest in the application of brucite (crystalline Mg(OH)2) as a flame retardant filler in polymer formulations is motivated by advantages of this material over halogenated flame retardants, which include environmental and health compatibility. ...

Charlene R. S. Matos; Maria José Xavier; Ledjane S. Barreto; Nivan B. Costa, Jr.; Iara F. Gimenez

2007-01-09T23:59:59.000Z

462

Fast neutron imaging device and method  

DOE Patents [OSTI]

A fast neutron imaging apparatus and method of constructing fast neutron radiography images, the apparatus including a neutron source and a detector that provides event-by-event acquisition of position and energy deposition, and optionally timing and pulse shape for each individual neutron event detected by the detector. The method for constructing fast neutron radiography images utilizes the apparatus of the invention.

Popov, Vladimir; Degtiarenko, Pavel; Musatov, Igor V.

2014-02-11T23:59:59.000Z

463

Proton recoil scintillator neutron rem meter  

DOE Patents [OSTI]

A neutron rem meter utilizing proton recoil and thermal neutron scintillators to provide neutron detection and dose measurement. In using both fast scintillators and a thermal neutron scintillator the meter provides a wide range of sensitivity, uniform directional response, and uniform dose response. The scintillators output light to a photomultiplier tube that produces an electrical signal to an external neutron counter.

Olsher, Richard H. (Los Alamos, NM); Seagraves, David T. (Los Alamos, NM)

2003-01-01T23:59:59.000Z

464

Spallation Neutron Sources Around the World  

E-Print Network [OSTI]

Spallation Neutron Sources Around the World Bernie Riemer Thanks to others for the many shamelessly Laboratory #12;2 Managed by UT-Battelle for the U.S. Department of Energy Spallation Neutron Source Facilities Spallation Neutron Source Facilities Serve Neutron Science Programs · Neutron beams to suites

McDonald, Kirk

465

Predictions of diffractive cross sections in proton-proton collisions  

SciTech Connect (OSTI)

We review our pre-LHC predictions of the total, elastic, total-inelastic, and diffractive components of proton-proton cross sections at high energies, expressed in the form of unitarized expressions based on a special parton-model approach to diffraction employing inclusive proton parton distribution functions and QCD color factors and compare with recent LHC results.

Goulianos, Konstantin [Rockefeller University, 1230 York Avenue, New York, NY 10065 (United States)

2013-04-15T23:59:59.000Z

466

X-ray Diffraction Laboratory Department of Chemistry  

E-Print Network [OSTI]

X-ray Diffraction Laboratory Department of Chemistry Texas A & M University College Station, Texas Phone : 979-845-9125 www.chem.tamu.edu/xray xray@tamu.edu X-rayDiffractionLaboratory DepartmentofChemistry 3255TAMU CollegeStation,TX77843-3255 Mission The purpose of our laboratory is to provide X-ray

Meagher, Mary

467

X-ray Diffraction Practicals 1 Graphics Programs  

E-Print Network [OSTI]

X-ray Diffraction Practicals 1 Graphics Programs that will read SHELX or CIF files J. Reibenspies, N. Bhuvanesh ver 1.0.0 #12;X-ray Diffraction Practicals 2 Free software. Gretep : Reads SHELX files shelx files or output thermal ellipsoid plots. http://www.umass.edu/microbio/rasmol/ #12;X-ray

Meagher, Mary

468

Di-neutron correlation in light neutron-rich nuclei  

E-Print Network [OSTI]

Using a three-body model with density-dependent contact interaction, we discuss the root mean square distance between the two valence neutrons in $^{11}$Li nuclues as a function of the center of mass of the neutrons relative to the core nucleus $^9$Li. We show that the mean distance takes a pronounced minimum around the surface of the nucleus, indicating a strong surface di-neutron correlation. We demonstrate that the pairing correlation plays an essential role in this behavior. We also discuss the di-neutron structure in the $^8$He nucleus.

K. Hagino; H. Sagawa; P. Schuck

2008-12-03T23:59:59.000Z

469

REVIEW OF NON-NEUTRON AND NEUTRON NUCLEAR DATA, 2004.  

SciTech Connect (OSTI)

Review articles are in preparation for the 2004 edition of the CRC Handbook of Chemistry and Physics dealing with the evaluation of both non-neutron and neutron nuclear data. Data on the discovery of element 110, Darmstadtium, and element 111 have been officially accepted, while data on element 11 8 have been withdrawn. Data to be presented include revised values for very short-lived nuclides, long-lived nuclides and beta-beta decay measurements. There has been a reassessment of the spontaneous fission (sf) half-lives, which distinguishes between sf decay half-lives and cluster decay half-lives and with cluster-fission decay. New measurements of isotopic abundance values for many elements will be discussed with an emphasis on the minor isotopes of interest for use in neutron activation analysis measurements. Neutron resonance integrals will be discussed emphasizing the differences between the calculated values obtained from the analytical integration over neutron resonances and the measured values in a neutron reactor-spectrum, which does not quite conform to the assumed 1/E neutron energy spectrum. The method used to determine the neutron resonance integral from measurement, using neutron activation analysis, will be discussed.

HOLDEN, N.E.

2004-09-26T23:59:59.000Z

470

Review of Non?Neutron and Neutron Nuclear Data, 2004  

Science Journals Connector (OSTI)

Review articles are in preparation for the 2004 edition of the CRC Handbook of Chemistry and Physics dealing with the evaluation of both non?neutron and neutron nuclear data. Data on the discovery of element 110 Darmstadtium and element 111 have been officially accepted while data on element 118 have been withdrawn. Data to be presented include revised values for very short?lived nuclides long?lived nuclides and beta?beta decay measurements. There has been a reassessment of the spontaneous fission (sf) half?lives which distinguishes between sf decay half?lives and cluster decay half?lives and with cluster?fission decay. New measurements of isotopic abundance values for many elements will be discussed with an emphasis on the minor isotopes of interest for use in neutron activation analysis measurements. Neutron resonance integrals will be discussed emphasizing the differences between the calculated values obtained from the analytical integration over neutron resonances and the measured values in a neutron reactor?spectrum which does not quite conform to the assumed 1/E neutron energy spectrum. The method used to determine the neutron resonance integral from measurement using neutron activation analysis will be discussed.

Norman E. Holden

2005-01-01T23:59:59.000Z

471

Analysis of experimental data on the neutron yield from muons  

SciTech Connect (OSTI)

Experimental data accumulated over 60 years of studying the yield of cosmogenic neutrons in a liquid scintillator (Y{sub LS}), iron (Y{sub Fe}), and lead (Y{sub Pb}) were analyzed. This analysis revealed that the main part of the results on the yield Y{sub LS} were overestimated by about 30%. With allowance for this circumstance, all experimental data can be described by the dependence Y(E{sub Micro-Sign }, A) = b{sub n}A{sup {beta}}E{sub Micro-Sign }{sup {alpha}}, where the product b{sub n}E{sub Micro-Sign }{sup {alpha}} stands for the energy spent by a muon on neutron production. The exponents of {alpha} = 0.78 and {beta} = 0.95 are determined by the properties of the medium and by neutron production in showers.

Agafonova, N. Yu.; Malgin, A. S., E-mail: Malgin@lngs.infn.it [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)

2013-05-15T23:59:59.000Z

472

Hubble Sees a Neutron Star Alone in Space Nearest Known Neutron Star  

E-Print Network [OSTI]

Hubble Sees a Neutron Star Alone in Space Nearest Known Neutron Star #12;Birth of a Neutron Star In the core, nuclei are smashed into protons & neutrons; the protons combine with electrons to make neutrons & neutrinos. The birth temperature of a neutron star is ~5Ã?1011 K, but neutrino emission cools it to `only

Barnes, Joshua Edward

473

X-Ray Diffraction Microscopy of Magnetic Structures  

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

X-Ray Diffraction Microscopy of Magnetic Structures Print X-Ray Diffraction Microscopy of Magnetic Structures Print science brief icon Scientists working at ALS Beamline 12.0.2.2 have demonstrated a new x-ray technique for producing short-exposure nanoscale images of the magnetic structure of materials. The new method combines aspects of coherent x-ray diffraction, which can determine 3-D charge distributions, and resonant magnetic scattering, which is sensitive to magnetic structures. Physicists have used coherent x-ray diffraction to measure the electron density of complicated molecules. The formula used to make these calculations contains terms that relate to the electron spin of magnetic atoms, but these terms are traditionally ignored since coherent x-ray diffraction has not been used to retrieve magnetic information. Using the full formula allows for the determination of not only the electron density, but also the magnetic spin distribution and its orientation.

474

X-Ray Diffraction Microscopy of Magnetic Structures  

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

X-Ray Diffraction Microscopy of Magnetic Structures Print X-Ray Diffraction Microscopy of Magnetic Structures Print science brief icon Scientists working at ALS Beamline 12.0.2.2 have demonstrated a new x-ray technique for producing short-exposure nanoscale images of the magnetic structure of materials. The new method combines aspects of coherent x-ray diffraction, which can determine 3-D charge distributions, and resonant magnetic scattering, which is sensitive to magnetic structures. Physicists have used coherent x-ray diffraction to measure the electron density of complicated molecules. The formula used to make these calculations contains terms that relate to the electron spin of magnetic atoms, but these terms are traditionally ignored since coherent x-ray diffraction has not been used to retrieve magnetic information. Using the full formula allows for the determination of not only the electron density, but also the magnetic spin distribution and its orientation.

475

X-Ray Diffraction Microscopy of Magnetic Structures  

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

X-Ray Diffraction Microscopy of Magnetic Structures Print X-Ray Diffraction Microscopy of Magnetic Structures Print science brief icon Scientists working at ALS Beamline 12.0.2.2 have demonstrated a new x-ray technique for producing short-exposure nanoscale images of the magnetic structure of materials. The new method combines aspects of coherent x-ray diffraction, which can determine 3-D charge distributions, and resonant magnetic scattering, which is sensitive to magnetic structures. Physicists have used coherent x-ray diffraction to measure the electron density of complicated molecules. The formula used to make these calculations contains terms that relate to the electron spin of magnetic atoms, but these terms are traditionally ignored since coherent x-ray diffraction has not been used to retrieve magnetic information. Using the full formula allows for the determination of not only the electron density, but also the magnetic spin distribution and its orientation.

476

Structure and dynamics of cadmium telluride studied by x-ray and inelastic neutron scattering  

SciTech Connect (OSTI)

We present a combined study of density functional theory, x-ray diffraction, and inelastic neutron scattering examining the temperature dependent structure and lattice dynamics of commercially available cadmium telluride. A subtle change in the structure is evinced near 80~K, which manifests also in the measured phonon density of states. There is no change to the long-range ordered structure. The implications of the change in relation to structural defects are discussed.

Niedziela, Jennifer L [ORNL; Stone, Matthew B [ORNL

2014-01-01T23:59:59.000Z

477

Neutron Imaging by Boric Acid  

E-Print Network [OSTI]

In this paper a new type of passive neutron detector based on the already existing one, CR39, is described. Its operation was verified by three different neutron sources: an Americium-Beryllium (Am241-Be) source; a TRIGA type nuclear reactor; and a fast neutron reactor called TAPIRO. The obtained results, reported here, positively confirm its operation and the accountability of the new developed detecting technique.

Fabio Cardone; Giovanni Cherubini; Walter Perconti; Andrea Petrucci; Alberto Rosada

2013-02-22T23:59:59.000Z

478

Remote Laser Diffraction Particle Size Distribution Analyzer  

SciTech Connect (OSTI)

In support of a radioactive slurry sampling and physical characterization task, an “off-the-shelf” laser diffraction (classical light scattering) particle size analyzer was utilized for remote particle size distribution (PSD) analysis. Spent nuclear fuel was previously reprocessed at the Idaho Nuclear Technology and Engineering Center (INTEC—formerly recognized as the Idaho Chemical Processing Plant) which is on DOE’s INEEL site. The acidic, radioactive aqueous raffinate streams from these processes were transferred to 300,000 gallon stainless steel storage vessels located in the INTEC Tank Farm area. Due to the transfer piping configuration in these vessels, complete removal of the liquid can not be achieved. Consequently, a “heel” slurry remains at the bottom of an “emptied” vessel. Particle size distribution characterization of the settled solids in this remaining heel slurry, as well as suspended solids in the tank liquid, is the goal of this remote PSD analyzer task. A Horiba Instruments Inc. Model LA-300 PSD analyzer, which has a 0.1 to 600 micron measurement range, was modified for remote application in a “hot cell” (gamma radiation) environment. This technology provides rapid and simple PSD analysis, especially down in the fine and microscopic particle size regime. Particle size analysis of these radioactive slurries down in this smaller range was not previously achievable—making this technology far superior than the traditional methods used. Successful acquisition of this data, in conjunction with other characterization analyses, provides important information that can be used in the myriad of potential radioactive waste management alternatives.

Batcheller, Thomas Aquinas; Huestis, Gary Michael; Bolton, Steven Michael

2001-03-01T23:59:59.000Z

479

Final Report: Algorithms for Diffractive Microscopy  

SciTech Connect (OSTI)

The phenomenal coherence and brightness of x-ray free-electron laser light sources, such as the LCLS at SLAC, have the potential of revolutionizing the investigation of structure and dynamics in the nano-domain. However, this potential will go unrealized without a similar revolution in the way the data are analyzed. While it is true that the ambitious design parameters of the LCLS have been achieved, the prospects of realizing the most publicized goal of this instrument — the imaging of individual bio-particles — remains daunting. Even with 10{sup 12} photons per x-ray pulse, the feebleness of the scattering process represents a fundamental limit that no amount of engineering ingenuity can overcome. Large bio-molecules will scatter on the order of only 10{sup 3} photons per pulse into a detector with 106 pixels; the diffraction “images” will be virtually indistinguishable from noise. Averaging such noisy signals over many pulses is not possible because the particle orientation cannot be controlled. Each noisy laser snapshot is thus confounded by the unknown viewpoint of the particle. Given the heavy DOE investment in LCLS and the profound technical challenges facing single-particle imaging, the final two years of this project have concentrated on this effort. We are happy to report that we succeeded in developing an extremely efficient algorithm that can reconstruct the shapes of particles at even the extremes of noise expected in future LCLS experiments with single bio-particles. Since this is the most important outcome of this project, the major part of this report documents this accomplishment. The theoretical techniques that were developed for the single-particle imaging project have proved useful in other imaging problems that are described at the end of the report.

Elser, Veit

2010-10-08T23:59:59.000Z

480

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

Note: This page contains sample records for the topic "neutron diffraction reveals" 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

Oscillations During Thermonuclear X-ray Bursts: A New Probe of Neutron Stars  

E-Print Network [OSTI]

Observations of thermonuclear (Type I) X-ray bursts from neutron stars in low mass X-ray binaries (LMXB) with the Rossi X-ray Timing Explorer (RXTE) have revealed large amplitude, high coherence X-ray brightness oscillations with frequencies in the 300 - 600 Hz range. Substantial spectral and timing evidence point to rotational modulation of the X-ray burst flux as the cause of these oscillations, and it is likely that they reveal the spin frequencies of neutron stars in LMXB from which they are detected. Here I review the status of our knowledge of these oscillations and describe how they can be used to constrain the masses and radii of neutron stars as well as the physics of thermonuclear burning on accreting neutron stars.

Tod E. Strohmayer

1999-11-19T23:59:59.000Z

482

Diffraction Studies of Ordered Phases and Phase Transitions  

E-Print Network [OSTI]

on graphite and A neutron scattering study of the diluted uniaxial dipolar coupled ferromagnets LiTb.3Y.7F4 transition, the critical neutron scattering of either crystal exhibits the asymmetry characteristic PHASES AND PHASE TRANSITIONS: A synchrotron x-ray scattering study of monolayers of CF4 adsorbed

483

Los Alamos Neutron Science Center  

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

Neutron Science Center gets capacity boost December 2, 2010 Los Alamos National Security funds upgrade to key facility LOS ALAMOS, New Mexico, December 2, 2010-The National Nuclear...

484

CHRPR Neutron Board Replacement Manual  

SciTech Connect (OSTI)

This document will walk through the steps to exchange the neutron channel boards with gamma channel boards in the CHRPR box.

Erikson, Rebecca L.; Myjak, Mitchell J.

2013-03-31T23:59:59.000Z

485

Supporting Organizations | Neutron Science | ORNL  

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

support the researchers and maintain the instruments used across all of our neutron science research: Biology and Soft Matter Division The Biology and Soft Matter...

486

Portable neutron spectrometer and dosimeter  

DOE Patents [OSTI]

The disclosure relates to a battery operated neutron spectrometer/dosimeter utilizing a microprocessor, a built-in tissue equivalent LET neutron detector, and a 128-channel pulse height analyzer with integral liquid crystal display. The apparatus calculates doses and dose rates from neutrons incident on the detector and displays a spectrum of rad or rem as a function of keV per micron of equivalent tissue and also calculates and displays accumulated dose in millirads and millirem as well as neutron dose rates in millirads per hour and millirem per hour.

Waechter, David A. (Los Alamos, NM); Erkkila, Bruce H. (Los Alamos, NM); Vasilik, Dennis G. (Los Alamos, NM)

1985-01-01T23:59:59.000Z

487

LANSCE | Lujan Neutron Scattering Center  

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

Lujan Center Data Management Lujan Neutron Scattering Center Logo The Lujan Center within LANSCE utilizes a pulsed source and has a complement of 15 instruments. It maintains a...

488

Scattering of Neutrons by Lead  

Science Journals Connector (OSTI)

... THE University of Cambridge cyclotron and neutron velocity selector have been used for studying the ... velocity selector have been used for studying the scattering of ...

R. LATHAM; J. M. CASSELS

1948-02-21T23:59:59.000Z

489

2011 U.S. National School on Neutron and X-ray Scattering  

SciTech Connect (OSTI)

The 13th annual U.S. National School on Neutron and X-ray Scattering was held June 11 to 25, 2011, at both Oak Ridge and Argonne National Laboratories. This school brought together 65 early career graduate students from 56 different universities in the US and provided them with a broad introduction to the techniques available at the major large-scale neutron and synchrotron x-ray facilities. This school is focused primarily on techniques relevant to the physical sciences, but also touches on cross-disciplinary bio-related scattering measurements. During the school, students received lectures by over 30 researchers from academia, industry, and national laboratories and participated in a number of short demonstration experiments at Argonne's Advanced Photon Source (APS) and Oak Ridge's Spallation neutron Source (SNS) and High Flux Isotope Reactor (HFIR) facilities to get hands-on experience in using neutron and synchrotron sources. The first week of this year's school was held at Oak Ridge National Lab, where Lab director Thom Mason welcomed the students and provided a shitorical perspective of the neutron and x-ray facilities both at Oak Ridge and Argonne. The first few days of the school were dedicated to lectures laying out the basics of scattering theory and the differences and complementarity between the neutron and x-ray probes given by Sunil Sinha. Jack Carpenter provided an introduction into how neutrons are generated and detected. After this basic introduction, the students received lectures each morning on specific techniques and conducted demonstration experiments each afternoon on one of 15 different instruments at either the SNS or HFIR. Some of the topics covered during this week of the school included inelastic neutron scattering by Bruce Gaulin, x-ray and neutron reflectivity by Chuck Majkrazak, small-angle scattering by Volker Urban, powder diffraction by Ashfia Huq and diffuse scattering by Gene Ice.

Lang, Jonathan [Argonne National Laboratory (ANL); te Vethuis, Suzanne [Argonne National Laboratory (ANL); Ekkebus, Allen E [ORNL; Chakoumakos, Bryan C [ORNL; Budai, John D [ORNL

2012-01-01T23:59:59.000Z

490

Inelastic neutron scattering study on bioprotectant systems  

Science Journals Connector (OSTI)

...22 December 2005 Inelastic neutron scattering study on bioprotectant systems...UK We collected inelastic neutron scattering (INS) spectra of homologous...vibrational properties|neutron scattering| 1. Introduction In recent...

2005-01-01T23:59:59.000Z

491

Neutron scattering from adsorbed polymer layers  

Science Journals Connector (OSTI)

Neutron scattering from adsorbed polymer layers ... Small-Angle Neutron Scattering Study of Cyclic Poly(ethylene glycol) Adsorption on Colloidal Particles ... Small-Angle Neutron Scattering Study of Cyclic Poly(ethylene glycol) Adsorption on Colloidal Particles ...

Terence Cosgrove; Timothy G. Heath; Keith Ryan; Trevor L. Crowley

1987-11-01T23:59:59.000Z

492

Protein structures by spallation neutron crystallography  

Science Journals Connector (OSTI)

The capabilities of the Protein Crystallography Station at Los Alamos Neutron Science Center for determining protein structures by spallation neutron crystallography are illustrated, and the methodological and technological advances that are emerging from the Macromolecular Neutron Crystallography consortium are described.

Langan, P.

2008-04-18T23:59:59.000Z

493

Inelastic Neutron Scattering from Glass Formers  

Science Journals Connector (OSTI)

......research-article Articles Inelastic Neutron Scattering from Glass Formers U. Buchenau...transition. Coherent inelastic neutron scattering data indicate a mixture of...Supplement No. 126, 1997 Inelastic Neutron Scattering from Glass Formers U. BUCHENAU......

U. Buchenau

1997-01-01T23:59:59.000Z

494

Quasiclassical Approximation for Slow Neutron Scattering  

Science Journals Connector (OSTI)

......Approximation for Slow Neutron Scattering Takeo Nishigori Department...formula for the differential scattering cross section of a slow neutron is derived along the line...of Spherical Rotors and Neutron Scattering Juichiro Hama and Tuto......

Takeo Nishigori

1970-06-01T23:59:59.000Z

495

Neutron scattering in concrete and wood  

Science Journals Connector (OSTI)

......Article Computational techniques Neutron scattering in concrete and wood A. Facure...library were used to simulate the neutron scattering in barriers of conventional...of the barrier thickness on neutron scattering factors is also being studied......

A. Facure; A. X. Silva; R. C. Falcão; V. R. Crispim

2006-09-01T23:59:59.000Z

496

Neutron-deuteron breakup and quasielastic scattering  

E-Print Network [OSTI]

Quasielastic scattering and deuteron breakup in the 200 MeV region is studied by impinging a pulsed neutron beam on a deuterium target at the Weapons Neutron Research facility at the Los Alamos Neutron Science Center. The ...

Ohlson, Alice Elisabeth

2009-01-01T23:59:59.000Z

497

Neutron Scattering in ORNL'S Calibration Facility  

Science Journals Connector (OSTI)

......Dosimetry Article Neutron Scattering in ORNL'S Calibration...C. Francis Room scattering corrections for several common neutron detectors in a new...and enclosed room scattering situations are compared...good. A personnel neutron spectrometer was......

J.C. Liu; C.S. Sims; W.H. Casson; H. Murakami; C. Francis

1991-01-01T23:59:59.000Z

498

Neutron Generators for Spent Fuel Assay  

E-Print Network [OSTI]

13, 2010. [11] D-D Neutron Generator Development at LBNL, J.12] High-yield DT Neutron Generator, B.A. Ludewigt et al. ,a Compact High-Yield Neutron Generator, O. Waldmann and B.

Ludewigt, Bernhard A

2011-01-01T23:59:59.000Z

499

NEUTRON EMISSION IN RELATIVISTIC NUCLEAR COLLISIONS  

E-Print Network [OSTI]

Figure Captions Figure l. Neutron-to-proton ratio at 30° labapparent anomalies in the neutron-to-proton fragment ratio.3 proton data. Figure 2. Neutron-to-proton ratio R 1 , Solid

Stevenson, J.D.

2013-01-01T23:59:59.000Z

500

PRACTICAL NEUTRON DOSIMETRY AT HIGH ENERGIES  

E-Print Network [OSTI]

and Chupp, E. L. "Cosmic Ray Neutron Energy Spectrum." Phys.Study of Cosmic-Ray Neutrons." National Aero­ nautics andStudy of Cosmic-Ray Neutrons: Mid-Latitude Flights." Health

McCaslin, J.B.

2010-01-01T23:59:59.000Z