National Library of Energy BETA

Sample records for neutron powder diffraction

  1. Neutron powder diffraction analysis of (Tm{sub 0.50}Ca{sub 0...

    Office of Scientific and Technical Information (OSTI)

    Neutron powder diffraction analysis of (Tmsub 0.50Casub 0.50)MnOsub 3 and (Lusub 0.50Casub 0.50)MnOsub 3 Citation Details In-Document Search Title: Neutron powder ...

  2. Structural studies of magnesium nitride fluorides by powder neutron diffraction

    SciTech Connect (OSTI)

    Brogan, Michael A.; Hughes, Robert W.; Smith, Ronald I.; Gregory, Duncan H.

    2012-01-15

    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.

  3. Strain and particle size of palladium powders by time-of-flight neutron diffraction

    SciTech Connect (OSTI)

    Lawson, A.C.; Conant, J.W.; Talcott, C.L.; David, M.A.; Vaninetti, J.; Goldstone, J.A.; Williams, A.; Von Dreele, R.B.; Roof, R.B.; Hitterman, R.L.; Richardson, J.W. Jr.; Faber, J. Jr.

    1989-01-01

    We have determined the strain and particle size for several samples of palladium powder by time-of-flight neutron powder diffraction on two different diffractometers and by x-ray powder diffraction. The results are compared and found to be in fair agreement. The time-of-flight method gives good enough precision to reveal deficiencies in the simple models used for strain and particle size line broadening. 6 refs., 4 figs., 2 tabs.

  4. MnO spin-wave dispersion curves from neutron powder diffraction

    SciTech Connect (OSTI)

    Goodwin, Andrew L.; Dove, Martin T.; Tucker, Matthew G.; Keen, David A.

    2007-02-15

    We describe a model-independent approach for the extraction of spin-wave dispersion curves from powder neutron total scattering data. Our approach is based on a statistical analysis of real-space spin configurations to calculate spin-dynamical quantities. The RMCPROFILE implementation of the reverse Monte Carlo refinement process is used to generate a large ensemble of supercell spin configurations from MnO powder diffraction data collected at 100 K. Our analysis of these configurations gives spin-wave dispersion curves for MnO that agree well with those determined independently using neutron triple-axis spectroscopic techniques.

  5. Neutron and X-ray powder diffraction study of skutterudite thermoelectrics

    DOE PAGES-Beta [OSTI]

    Wang, H.; Kirkham, M. J.; Watkins, T. R.; Payzant, E. A.; Salvador, J. R.; Thompson, A. J.; Sharp, J.; Brown, D.; Miller, D.

    2016-02-17

    N- and p-type filled-skutterudite materials prepared for thermoelectric power generation modules were analyzed by neutron diffraction at the POWGEN beam line of the Spallation Neutron Source (SNS) and X-ray diffraction (XRD). The skutterudite powders were processed by melt spinning, followed by ball milling and annealing. The n-type material consists of Ba–Yb–Co–Sb and the p-type material consists of Di–Fe–Ni–Sb or Di–Fe–Co–Sb (Di = didymium, an alloy of Pr and Nd). Powders for prototype module fabrication from General Motors and Marlow Industries were analyzed in this study. XRD and neutron diffraction studies confirm that both the n- and p-type materials have cubicmore » symmetry. Structural Rietveld refinements determined the lattice parameters and atomic parameters of the framework and filler atoms. The cage filling fraction was found to depend linearly on the lattice parameter, which in turn depends on the average framework atom size. Ultimately, this knowledge may allow the filling fraction of these skutterudite materials to be purposefully adjusted, thereby tuning the thermoelectric properties.« less

  6. Applications of pulsed neutron powder diffraction to actinide elements. [Pu-Al

    SciTech Connect (OSTI)

    Lawson, A.C.; Richardson, J.W.; Mueller, M.H.; Lander, G.H.; Goldstone, J.A.; Williams, A.; Kwei, G.H.; Von Dreele, R.B.; Faber, J. Jr.; Hitterman, R.L.

    1987-11-01

    We have been using the technique of pulsed neutron powder diffraction to study several problems in the physics and chemistry of the actinide elements. In these elements one often encounters very complex structures resulting from polymorphic transformations presumably induced by the presence of 5f-electrons. For example, at least five distinct structures of plutonium metal are found between room temperature and its melting point of 640/sup 0/C, and two of the structures are monoclinc. The determination of the crystal structure of beta-uranium (tetragonal, 30 atoms per unit cell) which has finnaly been shown to be centrosymmetric, after decades of uncertainty is discussed. Some preliminary results on the structure of alpha-plutonium (which confirm Zachariasen's original determination of the monoclinic structure) are presented. Pu-Al alloys were also studied. 12 refs., 18 figs.

  7. Neutron powder diffraction study of tetragonal crystal structures of cerium-neodymium dicarbides

    SciTech Connect (OSTI)

    Jones, D.W.; McColm, I.J.; Steadman, R.; Yerkess, J.

    1986-04-01

    The three ternary cerium-neodymium dicarbides Ce/sub x/Nd/sub 1-x/C/sub 2/ (x = 0.25, 0.50, 0.75) and the two binary dicarbides CeC/sub 2/ and NdC/sub 2/ were prepared and their room temperature crystal structures examined by neutron powder diffraction by the Rietveld profile analysis method. The five compounds are isostructural, with tetragonal unit cell dimensions changing monotonically over the range a = 3.881(2), c = 6.487(3) A to a = 3.827(2), c = 6.407(2) A and they contain discrete acetylenic C-C groups with carbon-carbon bond lengths close to 1.29(1) A. 10 references, 1 figure, 1 table.

  8. Anomalous volume expansion in CaRu{sub 0.85}Fe{sub 0.15}O{sub 3}: Neutron powder diffraction and magnetic Compton scattering

    SciTech Connect (OSTI)

    Taniguchi, T.; Mizusaki, S.; Okada, N.; Nagata, Y.; Mori, K.; Wuernisha, T.; Kamiyama, T.; Hiraoka, N.; Itou, M.; Sakurai, Y.; Ozawa, T. C.; Noro, Y.; Samata, H.

    2007-01-01

    Neutron powder diffraction and magnetic Compton scattering measurements were conducted for ferromagnetic CaRu{sub 0.85}Fe{sub 0.15}O{sub 3} at temperatures between 10 and 300 K. Anomalous volume expansion was observed in the neutron diffraction measurement below the Curie temperature (85 K), and Invar-like behavior was observed below 40 K. However, no structural phase transition was observed down to 10 K. The strong correlation between the volume expansion, {delta}V, and the square magnetization, M{sup 2}, suggests that the anomalous volume expansion is due to the magnetovolume effect that is caused by the occurrence of ferromagnetism. The magnetic Compton scattering experiments revealed the existence of a magnetic moment on Ru and the antiferromagnetic configuration of Fe and Ru moments. The formation of a ferrimagnetic order through the induction of the magnetic moment on the Ru ion is a possible reason for the anomalous volume expansion observed for CaRu{sub 0.85}Fe{sub 0.15}O{sub 3}.

  9. A study of nitrogenation of a NdFe{sub 12-x}Mo{sub x} compound by in situ neutron powder diffraction.

    SciTech Connect (OSTI)

    Ding, Y.; Lin, J.; Loong, C.-K.; Short, S. M.

    1997-11-18

    The effects on the crystal lattice of a NdFe{sub 12{minus}x}Mo{sub x}(x {approx_equal} 1.7) compound which contained {approximately}12 vol% of bcc-Fe were studied by neutron powder diffraction during controlled nitrogenation over the 25-600 C temperature range. The sample inside the furnace was connected to a closed volume of ultra-pure nitrogen gas while neutron data were collected over regular time intervals during sequential heating. Substantial nitrogen absorption occurred between 500 to 600 C. During the nitrogenation process the NdFe{sub 12{minus}x}Mo{sub x}N{sub y} lattice expanded while the bcc-Fe lattice contracted. An increasing decomposition of the compound into bcc-Fe at 600 C was observed. The average size of the NdFe{sub 12{minus}x}Mo{sub x}N{sub y} crystalline grains decreased starting at {approximately}300 C, reaching a minimum at {approximately}500 C and then increased markedly at higher temperatures. The development of lattice strains, on the other hand, showed an opposite trend, i.e., a maximum at 500 C. A correlation of structural modification of the crystalline phases and the nitrogenation process is discussed.

  10. Crystal structure of α- and β-Na{sub 2}U{sub 2}O{sub 7}: From Rietveld refinement using powder neutron diffraction data

    SciTech Connect (OSTI)

    IJdo, D.J.W. Akerboom, S.; Bontenbal, A.

    2015-01-15

    The crystal structures of α- and β-Na{sub 2}U{sub 2}O{sub 7} have been determined from neutron powder diffraction. At 293 K, the compound α-Na{sub 2}U{sub 2}O{sub 7} has a monoclinic unit cell, space group P2{sub 1}/a, with a=12.7617(14) Å, b=7.8384(10) Å, c=6.8962(9) Å, β=111.285(9)°, and Z=4. At 773 K, β-Na{sub 2}U{sub 2}O{sub 7} is also monoclinic, space group C2/m, with a=12.933(1) Å, b=7.887(1) Å, c=6.9086(8) Å, β=110.816(10)°, and Z=4. The structures can be described by layers U{sub 2}O{sub 7}{sup 2−} built from corner linked deformed UO{sub 6} octahedra with pentagonal UO{sub 7} bipyramids in between linked with common edges to each other and to the octahedra. The Na atoms occupy the interlayer space. The Na{sub 2}U{sub 2}O{sub 7} layers are similar as in K{sub 2}U{sub 2}O{sub 7}, but with a different stacking sequence of the layers. The layers in β-Na{sub 2}U{sub 2}O{sub 7} are more symmetric. The relationship with the compounds A{sub 2}U{sub 2}O{sub 7} (A=K, Rb, and Cs) is discussed. - Graphical abstract: The U{sub 2}O{sub 7} layer of α-Na{sub 2}U{sub 2}O{sub 7} (left) at 293 K and of β-Na{sub 2}U{sub 2}O{sub 7} (right) at 773 K determined by neutron diffraction. Some Na atoms between the layers are visible. - Highlights: • Na{sub 2}U{sub 2}O{sub 7} has been prepared by means of a solid state reaction. • The structure has been determined using neutron diffraction. • At 293 K, the compound adopts a monoclinic structure with space group P2{sub 1}/a. • The structure at 773 K is closely related, and is described in the space group C2/m.

  11. Neutron detectors comprising boron powder

    DOE Patents [OSTI]

    Wang, Zhehui; Morris, Christopher; Bacon, Jeffrey Darnell; Makela, Mark F; Spaulding, Randy Jay

    2013-05-21

    High-efficiency neutron detector substrate assemblies comprising a first conductive substrate, wherein a first side of the substrate is in direct contact with a first layer of a powder material comprising .sup.10boron, .sup.10boron carbide or combinations thereof, and wherein a conductive material is in proximity to the first layer of powder material; and processes of making said neutron detector substrate assemblies.

  12. Neutron powder diffraction study of the layer organic-inorganic hybrid iron(II) methylphosphonate-hydrate, Fe[(CD{sub 3}PO{sub 3})(D{sub 2}O)

    SciTech Connect (OSTI)

    Leone, Philippe Bellitto, Carlo; Bauer, Elvira M.; Righini, Guido; Andre, Gilles; Bouree, Francoise

    2008-11-15

    The crystal and magnetic structures of the hybrid organic-inorganic layer compound Fe[(CD{sub 3}PO{sub 3})(D{sub 2}O)] have been studied by neutron powder diffraction as a function of temperature down to 1.5 K. The neutron diffraction pattern recorded at 200 K shows that the fully deuterated compound crystallizes in one of the two known forms of the undeuterated Fe[(CH{sub 3}PO{sub 3})(H{sub 2}O)]. The crystal structure is orthorhombic, space group Pmn2{sub 1}, with the following unit-cell parameters: a=5.7095(1) A, b=8.8053(3) A and c=4.7987(1) A; Z=2. The crystal structure remains unchanged on cooling from 200 to 1.5 K. Moreover, at low temperature, Fe[(CD{sub 3}PO{sub 3})(D{sub 2}O)] shows a commensurate magnetic structure (k=(0,0,0)). As revealed by bulk susceptibility measurements on Fe[(CH{sub 3}PO{sub 3})(H{sub 2}O)], the magnetic structure corresponds to a canted antiferromagnet with a critical temperature T{sub N}=25 K. Neutron powder diffraction reveals that below T{sub N}=23.5 K the iron magnetic moments in Fe[(CD{sub 3}PO{sub 3})(D{sub 2}O)] are antiferromagnetically coupled and oriented along the b-axis, perpendicular to the inorganic layers. No ferromagnetic component is observable in the neutron powder diffraction experiment, due to its too small value (<0.1{mu}{sub B}). - Graphical abstract: Crystal structure and magnetic structure of Fe[(CD{sub 3}PO{sub 3})(D{sub 2}O)].

  13. Palladium deuteride formation in the cathode of an electrochemical cell: An in situ neutron diffraction study

    SciTech Connect (OSTI)

    Rotella, F.J.; Richardson, J.W. Jr.; Redey, L.; Felcher, G.P.; Hitterman, R.L.; Kleb, R.

    1991-01-01

    In this report, neutron diffraction of palladium cathodes is utilized to reveal palladium deuteride formation within the crystal structure of the metal. The experiment described in this report demonstrates the efficacy of neutron powder diffraction as a tool for structural studies of metal deuterides/hydrides and the feasibility of in situ diffraction measurements from a working electrochemical cell. (JL)

  14. Palladium deuteride formation in the cathode of an electrochemical cell: An in situ neutron diffraction study

    SciTech Connect (OSTI)

    Rotella, F.J.; Richardson, J.W. Jr.; Redey, L.; Felcher, G.P.; Hitterman, R.L.; Kleb, R.

    1991-12-31

    In this report, neutron diffraction of palladium cathodes is utilized to reveal palladium deuteride formation within the crystal structure of the metal. The experiment described in this report demonstrates the efficacy of neutron powder diffraction as a tool for structural studies of metal deuterides/hydrides and the feasibility of in situ diffraction measurements from a working electrochemical cell. (JL)

  15. High-Pressure and High-Temperature Powder Diffraction (Journal...

    Office of Scientific and Technical Information (OSTI)

    High-Pressure and High-Temperature Powder Diffraction Citation Details In-Document Search Title: High-Pressure and High-Temperature Powder Diffraction Authors: Fei, Yingwei ; Wang, ...

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

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    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

  17. Hydrogen in polar intermetallics: Syntheses and structures of the ternary Ca5Bi3D0.93, Yb5Bi3Hx, and Sm5Bi3H~1 by powder neutron or single crystal X-ray diffraction

    SciTech Connect (OSTI)

    Leon-Escamilla, E. Alejandro; Dervenagas, Panagiotis; Stasis, Constantine; Corbett, John D.

    2010-01-01

    The syntheses of the title compounds are described in detail. Structural characterizations from refinements of single crystal X-ray diffraction data for Yb{sub 5}Bi{sub 3}H{sub x} and Sm{sub 5}Bi{sub 3}H{sub 1} and of powder neutron diffraction data for Ca{sub 5}Bi{sub 3}D{sub 0.93(3)} are reported. These confirm that all three crystallize with the heavy atom structure type of {beta}-Yb{sub 5}Sb{sub 3}, and the third gives the first proof that the deuterium lies in the center of nominal calcium tetrahedra, isostructural with the Ca{sub 5}Sb{sub 3}F-type structure. These Ca and Yb phases are particularly stable with respect to dissociation to Mn{sub 5}Si{sub 3}-type product plus H{sub 2}. Some contradictions in the literature regarding Yb{sub 5}Sb{sub 3} and Yb{sub 5}Sb{sub 3}H{sub x} phases are considered in terms of adventitious hydrogen impurities that are generated during reactions in fused silica containers at elevated temperatures.

  18. Quality experimental and calculated powder x-ray diffraction

    SciTech Connect (OSTI)

    Sullenger, D.B.; Cantrell, J.S.; Beiter, T.A.; Tomlin, D.W.

    1996-08-01

    For several years, we have submitted quality powder XRD patterns to the International Centre for Diffraction Data for inclusion as reference standards in their Powder Diffraction File. The procedure followed is described; examples used are {beta}-UH{sub 3}, {alpha}- BaT{sub 2}, alpha-lithium disilicate ({alpha}-Li{sub 2}Si{sub 2}O{sub 5}), and 2,2`,4,4`,6,6`hexanitroazobenzene-III (HNAB-III).

  19. LANSCE | Lujan Center | Highlights | In situ neutron diffraction...

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    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....

  20. Structural characterization of Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} as a function of temperature using neutron powder diffraction and extended X-ray absorption fine structure techniques

    SciTech Connect (OSTI)

    Mansour, A. N.; Wong-Ng, W.; Huang, Q.; Tang, W.; Thompson, A.; Sharp, J.

    2014-08-28

    The structure of Bi{sub 2}Te{sub 3} (Seebeck coefficient Standard Reference Material (SRM™ 3451)) and the related phase Sb{sub 2}Te{sub 3} have been characterized as a function of temperature using the neutron powder diffraction (NPD) and the extended X-ray absorption fine structure (EXAFS) techniques. The neutron structural studies were carried out from 20 K to 300 K for Bi{sub 2}Te{sub 3} and from 10 K to 298 K for Sb{sub 2}Te{sub 3}. The EXAFS technique for studying the local structure of the two compounds was conducted from 19 K to 298 K. Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} are isostructural, with a space group of R3{sup ¯}m. The structure consists of repeated quintuple layers of atoms, Te2-M-Te1-M-Te2 (where M = Bi or Sb) stacking along the c-axis of the unit cell. EXAFS was used to examine the bond distances and static and thermal disorders for the first three shells of Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} as a function of temperature. The temperature dependencies of thermal disorders were analyzed using the Debye and Einstein models for lattice vibrations. The Debye and Einstein temperatures for the first two shells of Bi{sub 2}Te{sub 3} are similar to those of Sb{sub 2}Te{sub 3} within the uncertainty in the data. However, the Debye and Einstein temperatures for the third shell of Bi-Bi are significantly lower than those of the third shell of Sb-Sb. The Einstein temperature for the third shell is consistent with a soft phonon mode in both Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3}. The lower Einstein temperature of Bi-Bi relative to Sb-Sb is consistent with the lower value of thermal conductivity of Bi{sub 2}Te{sub 3} relative to Sb{sub 2}Te{sub 3}.

  1. The Advanced Automation for Powder Diffraction toward Industrial Application

    SciTech Connect (OSTI)

    Osaka, Keiichi; Matsumoto, Takuya; Miura, Keiko; Sato, Masugu; Hirosawa, Ichiro; Watanabe, Yoshio

    2010-06-23

    A highly automated system for powder diffraction with synchrotron radiation was installed on the large Debye-Scherrer camera at the BL19B2 Engineering Science Research I beamline of SPring-8. Combined with a sample transfer and an automated centering system, we have succeeded in increasing the ratio of exposure time in the user beam time to 85%. The proposed system can be applied to a wide range of industrial uses.

  2. Structural properties of Sr{sub 0.61}Ba{sub 0.39}Nb{sub 2}O{sub 6} in the temperature range 10-500 K investigated by high-resolution neutron powder diffraction and specific heat measurements

    SciTech Connect (OSTI)

    Schefer, J.; Pomjakushin, V.; Stuhr, U.; Schaniel, D.; Woike, Th.; Petricek, V.; Woehlecke, M.; Imlau, M.

    2006-10-01

    We report high-resolution neutron powder diffraction on Sr{sub 0.61}Ba{sub 0.39}Nb{sub 2}O{sub 6} in the temperature range 15-500 K. The results indicate that the low-temperature anomalies (T{<=}100 K) observed in the dielectric dispersion are due to small changes in the incommensurate modulation of the NbO{sub 6} octahedra, as no structural phase transition of the average structure was observed. This interpretation is supported by specific heat measurements, which show no latent heat, but a glass-like behavior at low temperatures. Furthermore, we find that the structural changes connected with the ferroelectric phase transition at T{sub c}{approx_equal}350 K start already at 200 K, explaining the anisotropic thermal expansion in the temperature range 200-300 K observed in a recent x-ray diffraction study.

  3. Neutron detectors comprising ultra-thin layers of boron powder

    DOE Patents [OSTI]

    Wang, Zhehul; Morris, Christopher

    2013-07-23

    High-efficiency neutron detector substrate assemblies comprising a first conductive substrate, wherein a first side of the substrate is in direct contact with a first layer of a powder material having a thickness of from about 50 nm to about 250 nm and comprising .sup.10boron, .sup.10boron carbide or combinations thereof, and wherein a conductive material is in proximity to the first layer of powder material; and processes of making said neutron detector substrate assemblies.

  4. Electrostatic levitation facility optimized for neutron diffraction...

    Office of Scientific and Technical Information (OSTI)

    studies of high temperature liquids at a spallation neutron source Authors: Mauro, N. A. 1 ; Vogt, A. J. 2 Search DOE PAGES for author "Vogt, A. J." Search DOE PAGES for ...

  5. Determination of the response of pentaerythritol tetranitrate to static high pressure up to 4.2 GPa by neutron diffraction

    SciTech Connect (OSTI)

    Dick, J.J.; Dreele, R.B. von

    1997-11-01

    Neutron powder diffraction experiments were performed on pentaerythritol tetranitrate explosive up to 4.28 GPa. For deuterated samples the changes in lattice parameters, intramolecular torsional angles and molecular rotation were measured. The lattice parameter changes were different from those observed in protonated samples. However, there is no evidence of a phase transition or change in molecular symmetry.

  6. Asymmetric band flipping for time-of-flight neutron diffraction data

    DOE PAGES-Beta [OSTI]

    Whitfield, Pamela S.; Coelho, Alan A.

    2016-08-24

    Charge flipping with powder diffraction data is known to produce a result more reliably with high-resolution data,i.e.visible reflections at smalldspacings. This data are readily accessible with the neutron time-of-flight technique but the assumption that negative scattering density is nonphysical is no longer valid where elements with negative scattering lengths are present. The concept of band flipping was introduced in the literature, where a negative threshold is used in addition to a positive threshold during the flipping. But, it was not tested with experimental data at the time. Finallly, band flipping has been implemented inTOPAStogether with the band modification of low-densitymore » elimination and tested with experimental powder and Laue single-crystal neutron data.« less

  7. High throughput screening of ligand binding to macromolecules using high resolution powder diffraction

    DOE Patents [OSTI]

    Von Dreele, Robert B.; D'Amico, Kevin

    2006-10-31

    A process is provided for the high throughput screening of binding of ligands to macromolecules using high resolution powder diffraction data including producing a first sample slurry of a selected polycrystalline macromolecule material and a solvent, producing a second sample slurry of a selected polycrystalline macromolecule material, one or more ligands and the solvent, obtaining a high resolution powder diffraction pattern on each of said first sample slurry and the second sample slurry, and, comparing the high resolution powder diffraction pattern of the first sample slurry and the high resolution powder diffraction pattern of the second sample slurry whereby a difference in the high resolution powder diffraction patterns of the first sample slurry and the second sample slurry provides a positive indication for the formation of a complex between the selected polycrystalline macromolecule material and at least one of the one or more ligands.

  8. Synthesis under high-oxygen pressure, magnetic and structural characterization from neutron powder diffraction data of YGa{sub 1-x}Mn{sub 1+x}O{sub 5} (x = 0.23): A comparison with YMn{sub 2}O{sub 5}

    SciTech Connect (OSTI)

    Calle, C. de la Alonso, J.A.; Martinez-Lope, M.J.; Garcia-Hernandez, M.; Andre, G.

    2008-02-05

    A new material of nominal stoichiometry YGaMnO{sub 5} has been prepared in polycrystalline form from citrate precursors followed by thermal treatments under high-oxygen pressure. This compound has been characterized from neutron powder diffraction (NPD) data and magnetic measurements. For comparison, the parent compound YMn{sub 2}O{sub 5} has also been synthesized and its crystal structure refined by NPD data. The new oxide has an actual stoichiometry YGa{sub 1-x}Mn{sub 1+x}O{sub 5} (x = 0.23), determined by NPD, showing an important cationic disorder between both metal sites; it is orthorhombic, Pbam (SG), and its crystal structure contains chains of Mn{sup 4+}O{sub 6} edge-sharing octahedra, linked together by Ga{sup 3+}O{sub 5} pyramids and YO{sub 8} units. With respect to YMn{sub 2}O{sub 5}, containing axially elongated MnO{sub 5} pyramids due to the Jahn-Teller effect of Mn{sup 3+} cations, the GaO{sub 5} pyramidal units in YGa{sub 0.77}Mn{sub 1.23}O{sub 5} are substantially flattened. This compound has a paramagnetic behaviour with two weak anomalies at about 50 K and 350 K. The magnetic structures, studied at 1.4 K and 100 K show a ferromagnetic coupling along the chains of MnO{sub 6} octahedra.

  9. Long-range magnetic ordering in Ba{sub 2}CoS{sub 3}: A neutron diffraction study

    SciTech Connect (OSTI)

    Headspith, D.A. [Department of Chemistry, University of Hull, Cottingham Road, Hull HU6 7RX (United Kingdom); Battle, P.D. [Inorganic Chemistry Laboratory, Oxford University, South Parks Road, Oxford OX1 3QR (United Kingdom); Francesconi, M.G. [Department of Chemistry, University of Hull, Cottingham Road, Hull HU6 7RX (United Kingdom)], E-mail: m.g.francesconi@hull.ac.uk

    2007-10-15

    Neutron powder diffraction has been used to determine the magnetic structure of the quasi-one-dimensional compound Ba{sub 2}CoS{sub 3}, which contains linear [001] chains of vertex-sharing CoS{sub 4} tetrahedra, spaced apart by Ba{sup 2+} cations. At 1.5 K the Co{sup 2+} cations in the chains are antiferromagnetically ordered with an ordered magnetic moment of 1.97(4) {mu}{sub B} per cation aligned along [100]. Each Co{sup 2+} cation is ferromagnetically aligned with four cation in neighbouring chains and antiferromagnetically aligned with two others. - Graphical abstract: Neutron powder diffraction has been used to prove that Ba{sub 2}CoS{sub 3} shows long-range antiferromagnetic order at low temperatures, despite the quasi-one-dimensional arrangement of the CoS{sub 4} tetrahedra in the crystal structure.

  10. Double helix boron-10 powder thermal neutron detector

    DOE Patents [OSTI]

    Wang, Zhehui; Morris, Christopher L.; Bacon, Jeffrey D.

    2015-06-02

    A double-helix Boron-10 powder detector having intrinsic thermal neutron detection efficiency comparable to 36'' long, 2-in diameter, 2-bar Helium-3 detectors, and which can be used to replace such detectors for use in portal monitoring, is described. An embodiment of the detector includes a metallic plate coated with Boron-10 powder for generating alpha and Lithium-7 particles responsive to neutrons impinging thereon supported by insulators affixed to at least two opposing edges; a grounded first wire wound in a helical manner around two opposing insulators; and a second wire having a smaller diameter than that of the first wire, wound in a helical manner around the same insulators and spaced apart from the first wire, the second wire being positively biased. A gas, disposed within a gas-tight container enclosing the plate, insulators and wires, and capable of stopping alpha and Lithium-7 particles and generating electrons produces a signal on the second wire which is detected and subsequently related to the number of neutrons impinging on the plate.

  11. Neutron diffraction measurements and micromechanical modelling of temperature-dependent variations in TATB lattice parameters

    DOE PAGES-Beta [OSTI]

    Yeager, John D.; Luscher, Darby J.; Vogel, Sven C.; Clausen, Bjorn; Brown, Donald W.

    2016-06-01

    Triaminotrinitrobenzene (TATB) is a highly anisotropic molecular crystal used in several plastic-bonded explosive (PBX) formulations. TATB-based explosives exhibit irreversible volume expansion (“ratchet growth”) when thermally cycled. A theoretical understanding of the relationship between anisotropy of the crystal, crystal orientation distribution (texture) of polycrystalline aggregates, and the intergranular interactions leading to this irreversible growth is necessary to accurately develop physics-based predictive models for TATB-based PBXs under various thermal environments. In this work, TATB lattice parameters were measured using neutron diffraction during thermal cycling of loose powder and a pressed pellet. The measured lattice parameters help clarify conflicting reports in the literaturemore » as these new results are more consistent with one set of previous results than another. The lattice parameters of pressed TATB were also measured as a function of temperature, showing some differences from the powder. This data is used along with anisotropic single-crystal stiffness moduli reported in the literature to model the nominal stresses associated with intergranular constraints during thermal expansion. The texture of both specimens were characterized and the pressed pellet exhibits preferential orientation of (001) poles along the pressing direction, whereas no preferred orientation was found for the loose powder. Lastly, thermal strains for single-crystal TATB computed from lattice parameter data for the powder is input to a self-consistent micromechanical model, which predicts the lattice parameters of the constrained TATB crystals within the pellet. The agreement of these model results with the diffraction data obtained from the pellet is discussed along with future directions of research.« less

  12. Total-scattering pair-distribution function of organic material from powder electron diffraction data

    DOE PAGES-Beta [OSTI]

    Gorelik, Tatiana E.; Billinge, Simon J. L.; Schmidt, Martin U.; Kolb, Ute

    2015-04-01

    This paper shows for the first time that pair-distribution function analyses can be carried out on organic and organo-metallic compounds from powder electron diffraction data. Different experimental setups are demonstrated, including selected area electron diffraction (SAED) and nanodiffraction in transmission electron microscopy (TEM) or nanodiffraction in scanning transmission electron microscopy (STEM) modes. The methods were demonstrated on organo-metallic complexes (chlorinated and unchlorinated copper-phthalocyanine) and on purely organic compounds (quinacridone). The PDF curves from powder electron diffraction data, called ePDF, are in good agreement with PDF curves determined from X-ray powder data demonstrating that the problems of obtaining kinematical scattering datamore » and avoiding beam-damage of the sample are possible to resolve.« less

  13. Total-scattering pair-distribution function of organic material from powder electron diffraction data

    SciTech Connect (OSTI)

    Gorelik, Tatiana E.; Billinge, Simon J. L.; Schmidt, Martin U.; Kolb, Ute

    2015-04-01

    This paper shows for the first time that pair-distribution function analyses can be carried out on organic and organo-metallic compounds from powder electron diffraction data. Different experimental setups are demonstrated, including selected area electron diffraction (SAED) and nanodiffraction in transmission electron microscopy (TEM) or nanodiffraction in scanning transmission electron microscopy (STEM) modes. The methods were demonstrated on organo-metallic complexes (chlorinated and unchlorinated copper-phthalocyanine) and on purely organic compounds (quinacridone). The PDF curves from powder electron diffraction data, called ePDF, are in good agreement with PDF curves determined from X-ray powder data demonstrating that the problems of obtaining kinematical scattering data and avoiding beam-damage of the sample are possible to resolve.

  14. A New Camera for Powder Diffraction of Macromolecular Crystallography at SPring-8

    SciTech Connect (OSTI)

    Miura, Keiko; Inoue, Katsuaki; Goto, Shunji; Ishikawa, Tetsuya; Yamamoto, Masaki; Ueki, Tatzuo

    2004-05-12

    A powder diffractometer of Guinier geometry was developed and tested on a beamline, BL40B2, at SPring-8. The long specimen-to-detector distance, 1,000 mm, is advantageous in recording diffraction from Bragg spacing of 20 nm or larger. The angular resolution, 0.012 degrees, was realized together with the focusing optics, the long specimen-to-detector distance and the small pixel size of Blue-type Imaging Plate detector. Such a high resolution makes the peak separation possible in the powder diffraction from microcrystals with large unit cell and low symmetry of biological macromolecules.

  15. High-resolution neutron diffraction study of CuNCN: New evidence of structure anomalies at low temperature

    SciTech Connect (OSTI)

    Jacobs, Philipp; Houben, Andreas; Dronskowski, Richard; Tchougreff, Andrei L.; Lomonosov Moscow State University, Department of Chemistry and Poncelet Laboratory of Mathematics in Interaction with Physics and Informatics, Independent University of Moscow, Moscow Center for Continuous Mathematical Education, Bolshoi Vlasevsky Per. 11, 119002 Moscow

    2013-12-14

    Copper carbodiimide (CuNCN) is the nitrogen-containing analogue of cupric oxide. Based on high-resolution neutron-diffraction data, CuNCN's lattice parameters are derived as a function of the temperature. In accordance with a recent synchrotron study, a clear trend in the cell parameter a is observed accompanying the changing magnetic behavior. With decreasing temperature, a slowly decreases to a minimum at ?100 K after which it rises again. The same trendalbeit more pronouncedis observed for the c lattice parameter at ?35 K. The herein presented neutron powder-diffraction data also support the conjectured sequence of transitions from the high-temperature one-dimensional resonating valence-bond (RVB) state to a transient two-dimensional RVB state and eventually, at lowest temperatures, into another two-dimensional RVB state, presumably the ground state.

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

    SciTech Connect (OSTI)

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

    2014-11-15

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

  17. Density functional and neutron diffraction studies of lithium polymer electrolytes.

    SciTech Connect (OSTI)

    Baboul, A. G.

    1998-06-26

    The structure of PEO doped with lithium perchlorate has been determined using neutron diffraction on protonated and deuterated samples. The experiments were done in the liquid state. Preliminary analysis indicates the Li-O distance is about 2.0 {angstrom}. The geometries of a series of gas phase lithium salts [LiCF{sub 3}SO{sub 3}, Li(CF{sub 3}SO{sub 2}){sub 2}N, Li(CF{sub 3}SO{sub 2}){sub 2}CH, LiClO{sub 4}, LiPF{sub 6}, LiAsF{sub 6}] used in polymer electrolytes have been optimized at B3LYP/6-31G(d) density functional level of theory. All local minima have been identified. For the triflate, imide, methanide, and perchlorate anions, the lithium cation is coordinated to two oxygens and have binding energies of ca 141 kcal/mol at the B3LYP/6-311+G(3df,2p)/B3LYP/6-31G* level of theory. For the hexafluoroarsenate and hexafluorophosphate the lithium cation is coordinated to three oxygens and have binding energies of ca. 136 kcal/mol.

  18. The early development of neutron diffraction: Science in the wings of the Manhattan Project

    SciTech Connect (OSTI)

    Mason, Thom; Gawne, Timothy J; Nagler, Stephen E; Nestor, Margaret Boone {Bonnie}; Carpenter, John M

    2012-01-01

    Although neutron diffraction was first observed using radioactive decay sources shortly after the discovery of the neutron, it was only with the availability of higher intensity neutron beams from the first nuclear reactors, constructed as part of the Manhattan project, that systematic investigation of Bragg scattering became possible. Remarkably, at a time when the war effort was singularly focused on the development of the atomic bomb, groups working at Oak Ridge and Chicago carried out key measurements and recognized the future utility of neutron diffraction quite independent of its contributions to the measurements of nuclear cross sections. Ernest O. Wollan, Lyle B. Borst, and Walter H. Zinn were all able to observe neutron diffraction in 1944 using the X-10 graphite reactor and the CP-3 heavy water reactor.

  19. The early development of neutron diffraction: science in the wings of the Manhattan Project

    SciTech Connect (OSTI)

    Mason, T. E. Gawne, T. J.; Nagler, S. E.; Nestor, M. B.; Carpenter, J. M.

    2013-01-01

    Early neutron diffraction experiments performed in 1944 using the first nuclear reactors are described. Although neutron diffraction was first observed using radioactive decay sources shortly after the discovery of the neutron, it was only with the availability of higher intensity neutron beams from the first nuclear reactors, constructed as part of the Manhattan Project, that systematic investigation of Bragg scattering became possible. Remarkably, at a time when the war effort was singularly focused on the development of the atomic bomb, groups working at Oak Ridge and Chicago carried out key measurements and recognized the future utility of neutron diffraction quite independent of its contributions to the measurement of nuclear cross sections. Ernest O. Wollan, Lyle B. Borst and Walter H. Zinn were all able to observe neutron diffraction in 1944 using the X-10 graphite reactor and the CP-3 heavy water reactor. Subsequent work by Wollan and Clifford G. Shull, who joined Wollan’s group at Oak Ridge in 1946, laid the foundations for widespread application of neutron diffraction as an important research tool.

  20. Neutron irradiated uranium silicides studied by neutron diffraction and Rietveld analysis

    SciTech Connect (OSTI)

    Birtcher, R.C.; Mueller, M.H.; Richardson, J.W. Jr.

    1990-11-01

    The irradiation behavior of high-density uranium silicides has been a matter of interest to the nuclear industry for use in high power or low enrichment applications. Transmission electron microscopy studies have found that heavy ion bombardment renders U{sub 3}Si and U{sub 3}Si{sub 2} amorphous at temperatures below about 250 C and that U{sub 3}Si becomes mechanically unstable suffering rapid growth by plastic flow. In this present work, crystallographic changes preceding amorphization by fission fragment damage have been studied by high-resolution neutron diffraction as a function of damage produced by uranium fission at room temperature. Initially, both silicides had tetragonal crystal structures. Crystallographic and amorphous phases were studied simultaneously by combining conventional Rietveld refinement of the crystallographic phases with Fourier-filtering analysis of the non-crystalline scattering component. 13 refs., 5 figs.

  1. Single phase synthesis and room temperature neutron diffraction studies on multiferroic PbFe{sub 0.5}Nb{sub 0.5}O{sub 3}

    SciTech Connect (OSTI)

    Matteppanavar, Shidaling; Angadi, Basavaraj; Rayaprol, Sudhindra

    2013-02-05

    The lead-iron-niobate, (PbFe{sub 0.5}Nb{sub 0.5}O{sub 3} or PFN) was synthesized by low temperature sintering Single Step / Solid State Reaction Method. The 700 Degree-Sign C/2 hrs. calcined powder was sintered at 1050 Degree-Sign C/1 hr. The sintered pellets were characterized through X-Ray Diffraction and Neutron Diffraction at room temperature. It is found from the XRD pattern that the materials is in single phase with no traces of pyrochlore phase. It was also confirmed from the neutron diffraction pattern, the structure of PFN to be monoclinic, space group Cm. Structural studies has been carried out by refining the obtained neutron diffraction data by Rietveld refinement method using Fullprof program. The neutron diffraction pattern at 300 K (room temperature) was selected to refine the structure. The lattice parameters obtained are; a = 5.6709 A, b = 5.6732 A, c = 4.0136 A, and {alpha}= 90, {beta}= 89.881, {gamma}= 90. The P-E measurements showed hysteretic behavior with high remnant polarization.

  2. Neutron diffraction measurements of residual stresses in friction stir welding: a review

    SciTech Connect (OSTI)

    Woo, Wan Chuck [ORNL; Feng, Zhili [ORNL; Wang, Xun-Li [ORNL; David, Stan A [ORNL

    2011-01-01

    Significant amounts of residual stresses are often generated during welding and result in critical degradation of the structural integrity and performance of components. Neutron diffraction has become a well established technique for the determination of residual stresses in welds because of the unique deep penetration, three-dimensional mapping capability, and volume averaged bulk measurements characteristic of the scattering neutron beam. Friction stir welding has gained prominence in recent years. The authors reviewed a number of neutron diffraction measurements of residual stresses in friction stir welds and highlighted examples addressing how the microstructures and residual stresses are correlated with each other. An example of in situ neutron diffraction measurement result shows the evolution of the residual stresses during welding.

  3. Neutron diffraction and X-ray absorption study of Ag{sub 5}Pb{sub 2}O{sub 6}

    SciTech Connect (OSTI)

    Yoshii, K. Mizumaki, M.; Kato, K.; Uruga, T.; Abe, H.; Nakamura, A.; Shimojo, Y.; Ishii, Y.; Morii, Y.

    2007-01-15

    Neutron diffraction and X-ray absorption measurements were carried out for a silver-lead oxide Ag{sub 5}Pb{sub 2}O{sub 6}. The powder neutron diffraction patterns could be fitted to the trigonal P3-bar 1m structure, as was found by X-ray diffraction. From the bond-valence-sum (BVS) analysis, the valences of the Ag and Pb ions were estimated to be about 1+ and 3.7+, respectively. The X-ray absorption measurements indicated that the ionic state of Ag is close to 1+, while that of Pb stands between 3+ and 4+. The deviation of the valence of the Pb ion from 4+ suggests a contribution of Pb orbitals to the metallic conduction as well as the possible superconductivity of this material, consistently with a recent band-structure calculation.

  4. In-Situ Neutron Diffraction Studies of Complex Hydrogen Storage Materials

    SciTech Connect (OSTI)

    Yelon, William B.

    2013-05-13

    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.

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

    SciTech Connect (OSTI)

    Payzant, E Andrew; Bowman Jr, Robert C; Johnson, Terry A; Jorgensen, Scott W

    2013-01-01

    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.

  6. Kinetics of Methane Hydrate Decomposition Studied via in Situ Low Temperature X-ray Powder Diffraction

    SciTech Connect (OSTI)

    Everett, Susan M; Rawn, Claudia J; Keffer, David J.; Mull, Derek L; Payzant, E Andrew; Phelps, Tommy Joe

    2013-01-01

    Gas hydrates are known to have a slowed decomposition rate at ambient pressure and temperatures below the melting point of ice termed self-preservation or anomalous preservation. As hydrate exothermically decomposes, gas is released and water of the clathrate cages transforms into ice. Two regions of slowed decomposition for methane hydrate, 180 200 K and 230 260 K, were observed, and the kinetics were studied by in situ low temperature x-ray powder diffraction. The kinetic constants for ice formation from methane hydrate were determined by the Avrami model within each region and activation energies, Ea, were determined by the Arrhenius plot. Ea determined from the data for 180 200 K was 42 kJ/mol and for 230 260 K was 22 kJ/mol. The higher Ea in the colder temperature range was attributed to a difference in the microstructure of ice between the two regions.

  7. Pressure/temperature fluid cell apparatus for the neutron powder diffractometer instrument: Probing atomic structure in situ

    SciTech Connect (OSTI)

    Wang, Hsiu-Wen; Fanelli, Victor R.; Reiche, Helmut M.; Larson, Eric; Taylor, Mark A.; Siewenie, Joan; Xu, Hongwu; Zhu, Jinlong; Page, Katharine

    2014-12-15

    This contribution describes a new local structure compatible gas/liquid cell apparatus for probing disordered materials at high pressures and variable temperatures in the Neutron Powder Diffraction instrument at the Lujan Neutron Scattering Center, Los Alamos National Laboratory. The new sample environment offers choices for sample canister thickness and canister material type. Finite element modeling is utilized to establish maximum allowable working pressures of 414 MPa at 15 K and 121 MPa at 600 K. High quality atomic pair distribution function data extraction and modeling have been demonstrated for a calibration standard (Si powder) and for supercritical and subcritical CO{sub 2} measurements. The new sample environment was designed to specifically target experimental studies of the local atomic structures involved in geologic CO{sub 2} sequestration, but will be equally applicable to a wide variety of energy applications, including sorption of fluids on nano/meso-porous solids, clathrate hydrate formation, catalysis, carbon capture, and H{sub 2} and natural gas uptake/storage.

  8. Pressure/temperature fluid cell apparatus for the neutron powder diffractometer instrument: Probing atomic structure in situ

    DOE PAGES-Beta [OSTI]

    Wang, Hsiu -Wen; Fanelli, Victor R.; Reiche, Helmut M.; Larson, Eric; Taylor, Mark A.; Xu, Hongwu; Zhu, Jinlong; Siewenie, Joan; Page, Katharine

    2014-12-01

    This contribution describes a new local structure compatible gas/liquid cell apparatus for probing disordered materials at high pressures and variable temperatures in the Neutron Powder Diffraction instrument at the Lujan Neutron Scattering Center, Los Alamos National Laboratory. The new sample environment offers choices for sample canister thickness and canister material type. Finite element modeling is utilized to establish maximum allowable working pressures of 414 MPa at 15 K and 121 MPa at 600 K. High quality atomic pair distribution function data extraction and modeling have been demonstrated for a calibration standard (Si powder) and for supercritical and subcritical CO2measurements. Asmore » a result, the new sample environment was designed to specifically target experimental studies of the local atomic structures involved in geologic CO2 sequestration, but will be equally applicable to a wide variety of energy applications, including sorption of fluids on nano/meso-porous solids, clathrate hydrate formation, catalysis, carbon capture, and H2 and natural gas uptake/storage.« less

  9. Oxygen transport pathways in Ruddlesden–Popper structured oxides revealed via in situ neutron diffraction

    DOE PAGES-Beta [OSTI]

    Tomkiewicz, Alex C.; Tamimi, Mazin; Huq, Ashfia; McIntosh, Steven

    2015-09-21

    Ruddlesden-Popper structured oxides, general form An+1BnO3n+1, consist of n-layers of the perovskite structure stacked in between rock-salt layers, and have potential application in solid oxide electrochemical cells and ion transport membrane reactors. Three materials with constant Co/Fe ratio, LaSrCo0.5Fe0.5O4-δ (n = 1), La0.3Sr2.7CoFeO7-δ (n = 2), and LaSr3Co1.5Fe1.5O10-δ (n = 3) were synthesized and studied via in situ neutron powder diffraction between 765 K and 1070 K at a pO2 of 10-1 atm. Then, the structures were fit to a tetragonal I4/mmm space group, and were found to have increased total oxygen vacancy concentration in the order La0.3Sr2.7CoFeO7-δ > LaSr3Co1.5Fe1.5O10-δmore » > LaSrCo0.5Fe0.5O4-δ, following the trend predicted for charge compensation upon increasing Sr2+/La3+ ratio. The oxygen vacancies within the material were almost exclusively located within the perovskite layers for all of the crystal structures with only minimal vacancy formation in the rock-salt layer. Finally, analysis of the concentration of these vacancies at each distinct crystallographic site and the anisotropic atomic displacement parameters for the oxygen sites reveals potential preferred oxygen transport pathways through the perovskite layers.« less

  10. Neutron diffraction study of the beta' and gamma phases of LiFeO{sub 2}

    SciTech Connect (OSTI)

    Barre, Maud; Catti, Michele

    2009-09-15

    The beta, beta', gamma and alpha phases of LiFeO{sub 2}, synthesized as powders, were annealed at different temperatures and characterized by X-ray measurements. The beta' and gamma modifications were also studied by time-of-flight neutron diffraction (ISIS Facility, UK). The structure of the beta' phase was refined in the monoclinic C2/c space group (a=8.566(1), b=11.574(2), c=5.1970(5) A, beta=146.064(5){sup o}) to wR{sub p}=0.071-0.080 (data from four counter banks). Fe and Li atoms are ordered over two of the four independent sites, and partially disordered over the other two. The ordered Li has a distorted tetrahedral coordination. The gamma structure was refined at RT (a=4.047(1), c=8.746(2) A) and at 570 deg. C (a=4.082(3), c=8.822(6) A) in the I4{sub 1}/amd symmetry, showing full order with Li in octahedral coordination at RT, and in a split-atom configuration at high temperature. On annealing, the beta' polymorph was found to transform to gamma at 550 deg. C, thus suggesting that it is a metastable phase. Electrostatics is discussed as the driving force for the alpha->beta'->gamma ordering process of LiFeO{sub 2}. - Graphical abstract: Crystal structure of beta'-LiFeO{sub 2} (monoclinic C2/c). Lithium and iron atoms are both ordered (blue and yellow balls) and partially disordered (green balls) over four independent sites. The beta' phase transforms to fully ordered gamma (tetragonal I4{sub 1}/amd) at 550 deg. C.

  11. A method for the monitoring of metal recrystallization based on the in-situ measurement of the elastic energy release using neutron diffraction

    SciTech Connect (OSTI)

    Christien, F. Le Gall, R.; Telling, M. T. F.; Knight, K. S.

    2015-05-15

    A method is proposed for the monitoring of metal recrystallization using neutron diffraction that is based on the measurement of stored energy. Experiments were performed using deformed metal specimens heated in-situ while mounted at the sample position of the High Resolution Powder Diffractometer, HRPD (ISIS Facility), UK. Monitoring the breadth of the resulting Bragg lines during heating not only allows the time-dependence (or temperature-dependence) of the stored energy to be determined but also the recrystallized fraction. The analysis method presented here was developed using pure nickel (Ni270) specimens with different deformation levels from 0.29 to 0.94. In situ temperature ramping as well as isothermal annealing was undertaken. The method developed in this work allows accurate and quantitative monitoring of the recrystallization process. The results from neutron diffraction are satisfactorily compared to data obtained from calorimetry and hardness measurements.

  12. Neutron diffraction measurements of intergranular strains in MONEL-400

    SciTech Connect (OSTI)

    Holden, T.M.; Holt, R.A.; Clarke, A.P.

    1997-12-01

    Measurements have been made of the strain response parallel and perpendicular to an applied stress in uniaxial tensile specimens of MONEL-400. The diffraction elastic constants are in close agreement with the Kroener model. Beyond the yield point, different crystallographic orientations respond quite differently to the applied stress and, upon unloading, residual intergranular strains are generated which are tensile for some orientations and compressive for others. A simple theory based on the Taylor-Bishop-Hill (TBH) model gives a good qualitative description of the effects.

  13. Neutron diffraction measurements of dislocation density in copper crystals deformed at high strain rate

    SciTech Connect (OSTI)

    Rao, Mala N.; Chaplot, S. L.; Rawat, S.

    2013-02-05

    Neutron diffraction measurements of the rocking curves were carried out for single crystals of copper subjected to dynamic compression at 10{sup 3}/s strain rate. The line broadening is expected to be produced by dislocations, and an analysis of this broadening gives the dislocation density. Dislocation density is found to increase with increase of pressure.

  14. Processing of Neutron Diffraction Data for Strain Measurement in Geological Materials

    SciTech Connect (OSTI)

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

    2014-01-01

    : 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.

  15. Calculations of single crystal elastic constants for yttria partially stabilised zirconia from powder diffraction data

    SciTech Connect (OSTI)

    Lunt, A. J. G. Xie, M. Y.; Baimpas, N.; Korsunsky, A. M.; Zhang, S. Y.; Kabra, S.; Kelleher, J.; Neo, T. K.

    2014-08-07

    Yttria Stabilised Zirconia (YSZ) is a tough, phase-transforming ceramic that finds use in a wide range of commercial applications from dental prostheses to thermal barrier coatings. Micromechanical modelling of phase transformation can deliver reliable predictions in terms of the influence of temperature and stress. However, models must rely on the accurate knowledge of single crystal elastic stiffness constants. Some techniques for elastic stiffness determination are well-established. The most popular of these involve exploiting frequency shifts and phase velocities of acoustic waves. However, the application of these techniques to YSZ can be problematic due to the micro-twinning observed in larger crystals. Here, we propose an alternative approach based on selective elastic strain sampling (e.g., by diffraction) of grain ensembles sharing certain orientation, and the prediction of the same quantities by polycrystalline modelling, for example, the Reuss or Voigt average. The inverse problem arises consisting of adjusting the single crystal stiffness matrix to match the polycrystal predictions to observations. In the present model-matching study, we sought to determine the single crystal stiffness matrix of tetragonal YSZ using the results of time-of-flight neutron diffraction obtained from an in situ compression experiment and Finite Element modelling of the deformation of polycrystalline tetragonal YSZ. The best match between the model predictions and observations was obtained for the optimized stiffness values of C11 = 451, C33 = 302, C44 = 39, C66 = 82, C12 = 240, and C13 = 50 (units: GPa). Considering the significant amount of scatter in the published literature data, our result appears reasonably consistent.

  16. Electrostatic levitation facility optimized for neutron diffraction studies of high temperature liquids at a spallation neutron source

    DOE PAGES-Beta [OSTI]

    Mauro, N. A.; Vogt, A. J.; Derendorf, K. S.; Johnson, M. L.; Rustan, G. E.; Quirinale, D. G.; Kreyssig, A.; Lokshin, K. A.; Neuefeind, J. C.; An, Ke; et al

    2016-01-01

    Neutron diffraction studies of metallic liquids provide valuable information about inherent topological and chemical ordering on multiple length scales as well as insight into dynamical processes at the level of a few atoms. But, there exist very few facilities in the world that allow such studies to be made of reactive metallic liquids in a containerless environment, and these are designed for use at reactor-based neutron sources. We present an electrostatic levitation facility, NESL (for Neutron ElectroStatic Levitator), which takes advantage of the enhanced capabilities and increased neutron flux available at spallation neutron sources (SNSs). NESL enables high quality elasticmore » and inelastic neutron scattering experiments to be made of reactive metallic and other liquids in the equilibrium and supercooled temperature regime. The apparatus is comprised of a high vacuum chamber, external and internal neutron collimation optics, and a sample exchange mechanism that allows up to 30 samples to be processed between chamber openings. Two heating lasers allow excellent sample temperature homogeneity, even for samples approaching 500 mg, and an automated temperature control system allows isothermal measurements to be conducted for times approaching 2 h in the liquid state, with variations in the average sample temperature of less than 0.5%. Furthermore, to demonstrate the capabilities of the facility for elastic scattering studies of liquids, a high quality total structure factor for Zr64Ni36 measured slightly above the liquidus temperature is presented from experiments conducted on the nanoscale-ordered materials diffractometer (NOMAD) beam line at the SNS after only 30 min of acquisition time for a small sample ( 100 mg).« less

  17. Electrostatic levitation facility optimized for neutron diffraction studies of high temperature liquids at a spallation neutron source

    SciTech Connect (OSTI)

    Mauro, N. A.; Vogt, A. J.; Derendorf, K. S.; Johnson, M. L.; Rustan, G. E.; Quirinale, D. G.; Kreyssig, A.; Lokshin, K. A.; Neuefeind, J. C.; An, Ke; Wang, Xun-Li; Goldman, A. I.; Egami, T.; Kelton, K. F.

    2016-01-01

    Neutron diffraction studies of metallic liquids provide valuable information about inherent topological and chemical ordering on multiple length scales as well as insight into dynamical processes at the level of a few atoms. But, there exist very few facilities in the world that allow such studies to be made of reactive metallic liquids in a containerless environment, and these are designed for use at reactor-based neutron sources. We present an electrostatic levitation facility, NESL (for Neutron ElectroStatic Levitator), which takes advantage of the enhanced capabilities and increased neutron flux available at spallation neutron sources (SNSs). NESL enables high quality elastic and inelastic neutron scattering experiments to be made of reactive metallic and other liquids in the equilibrium and supercooled temperature regime. The apparatus is comprised of a high vacuum chamber, external and internal neutron collimation optics, and a sample exchange mechanism that allows up to 30 samples to be processed between chamber openings. Two heating lasers allow excellent sample temperature homogeneity, even for samples approaching 500 mg, and an automated temperature control system allows isothermal measurements to be conducted for times approaching 2 h in the liquid state, with variations in the average sample temperature of less than 0.5%. Furthermore, to demonstrate the capabilities of the facility for elastic scattering studies of liquids, a high quality total structure factor for Zr64Ni36 measured slightly above the liquidus temperature is presented from experiments conducted on the nanoscale-ordered materials diffractometer (NOMAD) beam line at the SNS after only 30 min of acquisition time for a small sample ( 100 mg).

  18. X-Ray Powder Diffraction Study of Synthetic Palmierite, K{sub 2}Pb(SO{sub 4}){sub 2}

    SciTech Connect (OSTI)

    TISSOT JR.,RALPH G.; RODRIGUEZ,MARK A.; SIPOLA,DIANA L.; VOIGT,JAMES A.

    2000-12-19

    Palmierite (K{sub 2}Pb(SO{sub 4}){sub 2}) has been prepared via a chemical synthesis method. Intensity differences were observed when X-ray powder data from the newly synthesized compound were compared to the published powder diffraction card (PDF) 29-1015 for Palmierite. Investigation of these differences indicated the possibility of preferred orientation and/or chemical inhomogeneity affecting intensities, particularly those of the basal (00{ell}) reflections. Annealing of the Palmierite was found to reduce the effects of preferred orientation. Electron microprobe analysis confirmed K:Pb:S as 2:1:2 for the annealed Palmierite powder. Subsequent least-squares refinement and Rietveld analysis of the annealed powder showed peak intensities very close to that of a calculated Palmierite pattern (based on single crystal data), yet substantially higher than many of the PDF 29-1015 published intensities. Further investigation of peak intensity variation via calculated patterns suggested that the intensity discrepancies between the annealed sample and those found in PDF 29-1015 were potentially due to chemical variation in the K{sub 2}Pb(SO{sub 4}){sub 2} composition. X-ray powder diffraction and crystal data for Palmierite are reported for the annealed sample. Palmierite is Trigonal/Hexagonal with unit cell parameters a = 5.497(1){angstrom}, c = 20.864(2) {angstrom}, space group R-3m (166), and Z = 3.

  19. X-ray and neutron diffraction of Er-hydride films.

    SciTech Connect (OSTI)

    Rodriguez, Mark Andrew

    2004-10-01

    The outline of this report is: (1) structures of hexagonal Er meal, ErH{sub 2} fluorite, and molybdenum; (2) texture issues and processing effects; (3) idea of pole figure integration; and (4) promising neutron diffraction work. Summary of this report are: (1) ErD{sub 2} and ErT{sub 2} film microstructures are strongly effected by processing conditions; (2) both x-ray and neutron diffraction are being pursued to help diagnose structure/property issues regarding ErT{sub 2} films and these correlations to He retention/release; (3) texture issues are great challenges for determination of site occupancy; and (4) work on pole-figure-integration looks to have promise addressing texture issues in ErD{sub 2} and ErT{sub 2} films.

  20. Irradiation creep of nano-powder sintered silicon carbide at low neutron fluences

    SciTech Connect (OSTI)

    Koyanagi, Takaaki; Shimoda, Kazuya; Kondo, Sosuke; Hinoki, Tatsuya; Ozawa, Kazumi; Katoh, Yutai

    2014-12-01

    The irradiation creep behavior of nano-powder sintered silicon carbide was investigated using the bend stress relaxation method under neutron irradiation up to 1.9 dpa. The creep deformation was observed at all temperatures ranging from 380 to 1180 C mainly from the irradiation creep but with the increasing contributions from the thermal creep at higher temperatures. Microstructural observation and data analysis were performed.

  1. Texture analysis of bulk YBa sub 2 Cu sub 3 O sub x by neutron diffraction

    SciTech Connect (OSTI)

    Kallend, J.S. ); Biondo, A.C.; Schultz, A.J.; Goretta, K.C. )

    1990-09-01

    Neutron diffraction has been used to generate Orientation Distribution Functions for two sinter-forged YBa{sub 2}Cu{sub 3}O{sub x} specimens. Sinter forging imparted a strong texture, with c axes of crystals preferentially aligned parallel to the forging direction. The distribution of a and b axes was not uniform, which may have implications to critical current density. 14 refs., 6 figs.

  2. The Crystal Structure of Thorium and Zirconium Dihydrides by X-ray and Neutron Diffraction

    DOE R&D Accomplishments [OSTI]

    Rundle, R.E.; Shull, C.G.; Wollan, E.O.

    1951-04-20

    Thorium forms a tetragonal lower hydride of composition ThH{sub 2}. The hydrides ThH{sub 2}, ThD{sub 2}, and ZrD{sub 2} have been studied by neutron diffraction in order that hydrogen positions could be determined. The hydrides are isomorphous, and have a deformed fluorite structure. Metal-hydrogen distances in thorium hydride are unusually large, as in UH{sub 3}. Thorium and zirconium scattering amplitudes and a revised scattering amplitude for deuterium are reported.

  3. Sample cell for powder x-ray diffraction at up to 500 bars and 200 deg. C

    SciTech Connect (OSTI)

    Jupe, Andrew C.; Wilkinson, Angus P.

    2006-11-15

    A low cost sample cell for powder diffraction at high pressure and temperature that employs either sapphire or steel pressure tubes is described. The cell can be assembled rapidly, facilitating the study of chemically reacting systems, and it provides good control of both pressure and temperature in a regimen where diamond anvil cells and multianvil apparatus cannot be used. The design provides a relatively large sample volume making it suitable for the study of quite large grain size materials, such as hydrating cement slurries. However, relatively high energy x rays are needed to penetrate the pressure tube.

  4. Sample cell for powder x-ray diffraction at up to 500 bars and 200 °C

    SciTech Connect (OSTI)

    Jupe, Andrew C.; Wilkinson, Angus P.

    2008-10-03

    A low cost sample cell for powder diffraction at high pressure and temperature that employs either sapphire or steel pressure tubes is described. The cell can be assembled rapidly, facilitating the study of chemically reacting systems, and it provides good control of both pressure and temperature in a regimen where diamond anvil cells and multianvil apparatus cannot be used. The design provides a relatively large sample volume making it suitable for the study of quite large grain size materials, such as hydrating cement slurries. However, relatively high energy x rays are needed to penetrate the pressure tube.

  5. Pressure dependence of the magnetic order in CrAs: a neutron diffraction investigation

    SciTech Connect (OSTI)

    Keller, L.; White, J. S.; Babkevich, P.; Susner, Michael A.; Sims, Zachary C; Safa-Sefat, Athena; Ronnow, H. M.; Ruegg, Ch.

    2015-01-29

    The suppression of magnetic order with pressure concomitant with the appearance of pressure-induced superconductivity was recently discovered in CrAs. Here we present a neutron diffraction study of the pressure evolution of the helimagnetic ground-state towards and in the vicinity of the superconducting phase. Neutron diffraction on polycrystalline CrAs was employed from zero pressure to 0.65 GPa and at various temperatures. The helimagnetic long-range order is sustained under pressure and the magnetic propagation vector does not show any considerable change. The average ordered magnetic moment is reduced from 1.73(2) μB at ambient pressure to 0.4(1) μB close to the critical pressure Pc ≈ 0.7 GPa, at which magnetic order is completely suppressed. The width of the magnetic Bragg peaks strongly depends on temperature and pressure, showing a maximum in the region of the onset of superconductivity. In conclusion, we interpret this as associated with competing ground-states in the vicinity of the superconducting phase.

  6. Synchrotron X-ray powder diffraction and convergent beam electron diffraction studies on the cubic phase of MgV{sub 2}O{sub 4} spinel

    SciTech Connect (OSTI)

    Niitaka, Seiji; Lee, Soyeon; Oshima, Yoshifumi; Kato, Kenichi; Hashizume, Daisuke; Takata, Masaki; Takagi, Hidenori

    2014-07-01

    The A V{sub 2}O{sub 4} (A=Mg{sup 2+}, Zn{sup 2+}, Cd{sup 2+}) spinels are three-dimensional spin-1 frustrated systems with orbital degree of freedom, which have been known to possess intriguing orbital states causing releases of spin frustration at low temperatures. We have performed synchrotron X-ray and convergent beam electron diffraction measurements for one of these vanadates, MgV{sub 2}O{sub 4} in order to clarify its crystal structure in the high temperature cubic phase, which is regarded as an important starting point for understanding the details of the low temperature phase. We have successfully observed that the [001] zone axis convergent beam electron diffraction pattern exhibits 4mm symmetry, suggesting the space group of Fd3{sup ¯}m in the cubic MgV{sub 2}O{sub 4}. It has also been demonstrated that the crystal structure of the cubic MgV{sub 2}O{sub 4} contains VO{sub 6} octahedra elongated along the threefold rotation axis. Based on our results, we discuss the orbital states of MgV{sub 2}O{sub 4} as well as the other spinel vanadates. - Graphical abstract: Precise geometry of the VO{sub 6} octahedra in the cubic phase of MgV{sub 2}O{sub 4} spinel determined with the synchrotron powder XRD data. - Highlights: • We examined the crystal structure of the cubic phase of MgV{sub 2}O{sub 4} spinel. • We prepared the single crystal and powdered sample of MgV{sub 2}O{sub 4} with high quality. • The result of the CBED measurement agrees with the space group of Fd3{sup ¯}m in the phase. • The cubic phase has VO{sub 6} octahedra elongated along the threefold rotation axis.

  7. Neutron diffraction studies of a four-coordinated hydride in near square-planar geometry

    SciTech Connect (OSTI)

    Liao, Jian -Hong; Dhayal, Rajendra Singh; Wang, Xiaoping; Kahlal, Samia; Saillard, Jean -Yves; Liu, C. W.

    2014-10-07

    The structure of a nanospheric polyhydrido copper cluster, [Cu20(H)11{S2P(OiPr)2}9], was determined by single-crystal neutron diffraction. Cu20 cluster consists of an elongated triangular orthobicupola constructed from 18 Cu atoms that encapsulate a [Cu2H5}3- ion in the center with an exceptionally short Cu-Cu distance. The eleven hydrides in the cluster display three different coordination modes to the Cu atoms: Six μ3-hydrides in pyramidal geometry, two μ4-hydrides in tetrahedral cavity, and three μ4-hydrides in an unprecedented near square-planar geometry. The neutron data set was collected on a small crystal of the size 0.20 mm x 0.50 mm x 0.65 mm for seven days using the Spallation Neutron Source TOPAZ single-crystal time-of-flight Laue diffractometer at the Oak Ridge National Laboratory. Furthermore, the final R-factor is 8.64% for 16014 reflections.

  8. Neutron diffraction studies of a four-coordinated hydride in near square-planar geometry

    DOE PAGES-Beta [OSTI]

    Liao, Jian -Hong; Dhayal, Rajendra Singh; Wang, Xiaoping; Kahlal, Samia; Saillard, Jean -Yves; Liu, C. W.

    2014-10-07

    The structure of a nanospheric polyhydrido copper cluster, [Cu20(H)11{S2P(OiPr)2}9], was determined by single-crystal neutron diffraction. Cu20 cluster consists of an elongated triangular orthobicupola constructed from 18 Cu atoms that encapsulate a [Cu2H5}3- ion in the center with an exceptionally short Cu-Cu distance. The eleven hydrides in the cluster display three different coordination modes to the Cu atoms: Six μ3-hydrides in pyramidal geometry, two μ4-hydrides in tetrahedral cavity, and three μ4-hydrides in an unprecedented near square-planar geometry. The neutron data set was collected on a small crystal of the size 0.20 mm x 0.50 mm x 0.65 mm for seven daysmore » using the Spallation Neutron Source TOPAZ single-crystal time-of-flight Laue diffractometer at the Oak Ridge National Laboratory. Furthermore, the final R-factor is 8.64% for 16014 reflections.« less

  9. Azine bridged silver coordination polymers: Powder X-ray diffraction route to crystal structure determination of silver benzotriazole

    SciTech Connect (OSTI)

    Rajeswaran, Manju . E-mail: manju.rajeswaran@kodak.com; Blanton, Thomas N.; Giesen, David J.; Whitcomb, David R.; Zumbulyadis, Nicholas; Antalek, Brian J.; Neumann, Marcus M.; Misture, Scott T.

    2006-04-15

    In continuation of our interest in solid-state structures of silver complexes of photographic importance, the structure for silver benzotriazole (AgBZT), has now been obtained. The preferred method for solving crystal structures is via single-crystal X-ray diffraction (XRD). However, for some materials, growing single crystals of appropriate size and quality is often difficult or even impossible. AgBZT is an example of such a silver complex with poor solubility. The usual routes to preparing single crystals using recrystallization from a cooperating solvent resulted in polycrystalline powder samples. We propose a crystal structure for AgBZT, solved from synchrotron X-ray powder diffraction data, using a direct-space Monte Carlo simulated annealing approach. AgBZT crystals are monoclinic (P2{sub 1} /c), with unit cell dimensions, a=14.8052(3) A, b=3.7498(4) A, c=12.3495(12) A, and {beta}=114.200(6){sup o}. The AgBZT complex is constructed from all three of the Benzotriazole (BZT) nitrogens bonding to a separate silver atom. As a consequence of this bonding mode, the structure is a highly cross-linked, coordination polymer.

  10. In-situ time-of-flight neutron diffraction of ErD2 (beta phase) formation during D2 loading.

    SciTech Connect (OSTI)

    Browning, James Frederick; Llobet, Anna; Snow, Clark Sheldon; Rodriguez, Mark Andrew; Wixom, Ryan R.

    2008-06-01

    In an effort to better understand the structural changes occurring during hydrogen loading of erbium target materials, we have performed D{sub 2} loading of erbium metal (powder) with simultaneous neutron diffraction analysis. This experiment tracked the conversion of Er metal to the {alpha} erbium deuteride (solid-solution) phase and then on to the {beta} (fluorite) phase. Complete conversion to ErD{sub 2.0} was accomplished at 10 Torr D{sub 2} pressure with deuterium fully occupying the tetrahedral sites in the fluorite lattice. Increased D{sub 2} pressure (up to 500 Torr at 450 C) revealed {approx}10 % deuterium occupation of the octahedral sites. Subsequent vacuum pumping of the sample at 450 C removed octahedral site occupancy while maintaining tetrahedral deuterium occupancy, thereby yielding stoichiometric ErD{sub 2.0} {beta} phase.

  11. Study of tempering behavior of lath martensite using in situ neutron diffraction

    SciTech Connect (OSTI)

    Shi, Z.M.; Gong, W.; Tomota, Y.; Harjo, S.; Li, J.; Chi, B.; Pu, J.

    2015-09-15

    To elucidate changes in the density and substructure of dislocations during tempering of lath martensite steel, a convolutional multiple whole-profile fitting method was applied to in situ neutron diffraction profiles. With increasing tempering temperature, the dislocation density scarcely changed in the beginning and then decreased at temperatures above 473 K, whereas the dislocation arrangement drastically changed at temperatures above 673 K. The strength of the steel is speculated to depend on the density and arrangement of dislocations. - Highlights: • A convolutional multiple whole-profile fitting method was applied. • Dislocation density and dislocation arrangement changing with tempering were discussed. • Dislocation density scarcely changed in the beginning. • And then dislocation density decreased at temperatures above 473 K. • The dislocation arrangement drastically changed at temperatures above 673 K.

  12. Pressure/temperature fluid cell apparatus for the neutron powder diffractometer instrument: Probing atomic structure in situ

    SciTech Connect (OSTI)

    Wang, Hsiu -Wen; Fanelli, Victor R.; Reiche, Helmut M.; Larson, Eric; Taylor, Mark A.; Xu, Hongwu; Zhu, Jinlong; Siewenie, Joan; Page, Katharine

    2014-12-24

    This contribution describes a new local structure compatible gas/liquid cell apparatus for probing disordered materials at high pressures and variable temperatures in the Neutron Powder Diffraction instrument at the Lujan Neutron Scattering Center, Los Alamos National Laboratory. The new sample environment offers choices for sample canister thickness and canister material type. Finite element modeling is utilized to establish maximum allowable working pressures of 414 MPa at 15 K and 121 MPa at 600 K. High quality atomic pair distribution function data extraction and modeling have been demonstrated for a calibration standard (Si powder) and for supercritical and subcritical CO2measurements. As a result, the new sample environment was designed to specifically target experimental studies of the local atomic structures involved in geologic CO2 sequestration, but will be equally applicable to a wide variety of energy applications, including sorption of fluids on nano/meso-porous solids, clathrate hydrate formation, catalysis, carbon capture, and H2 and natural gas uptake/storage.

  13. Quantitative determination of mineral composition by powder X-ray diffraction

    DOE Patents [OSTI]

    Pawloski, Gayle A.

    1986-01-01

    An external standard intensity ratio method is used for quantitatively determining mineralogic compositions of samples by x-ray diffraction. The method uses ratios of x-ray intensity peaks from a single run. Constants are previously determined for each mineral which is to be quantitatively measured. Ratios of the highest intensity peak of each mineral to be quantified in the sample and the highest intensity peak of a reference mineral contained in the sample are used to calculate sample composition.

  14. Quantitative determination of mineral composition by powder x-ray diffraction

    DOE Patents [OSTI]

    Pawloski, G.A.

    1984-08-10

    An external standard intensity ratio method is used for quantitatively determining mineralogic compositions of samples by x-ray diffraction. The method uses ratios of x-ray intensity peaks from a single run. Constants are previously determined for each mineral which is to be quantitatively measured. Ratios of the highest intensity peak of each mineral to be quantified in the sample and the highest intensity peak of a reference mineral contained in the sample are used to calculate sample composition.

  15. A comparison of dilatometry and in-situ neutron diffraction in tracking bulk phase transformations in a martensitic stainless steel

    SciTech Connect (OSTI)

    Christien, F.; Telling, M.T.F.; Knight, K.S.

    2013-08-15

    Phase transformations in the 17-4PH martensitic stainless steel have been studied using different in-situ techniques, including dilatometry and high resolution neutron diffraction. Neutron diffraction patterns were quantitatively processed using the Rietveld refinement method, allowing the determination of the temperature-dependence of martensite (α′, bcc) and austenite (γ, fcc) phase fractions and lattice parameters on heating to 1000 °C and then cooling to room temperature. It is demonstrated in this work that dilatometry doesn't permit an accurate determination of the end temperature (Ac3) of the α′ → γ transformation which occurs upon heating to high temperature. The analysis of neutron diffraction data has shown that the respective volumes of the two phases become very close to each other at high temperature, thus making the dilatometric technique almost insensitive in that temperature range. However, there is a very good agreement between neutron diffraction and dilatometry at lower temperature. The martensitic transformation occurring upon cooling has been analysed using the Koistinen–Marburger equation. The thermal expansion coefficients of the two phases have been determined in addition. A comparison of the results obtained in this work with data from literature is presented. - Highlights: • Martensite is still present at very high temperature (> 930 °C) upon heating. • The end of austenitisation cannot be accurately monitored by dilatometry. • The martensite and austenite volumes become similar at high temperature (> ∼ 850 °C)

  16. Structural phase transition and magnetism in hexagonal SrMnO{sub 3} by magnetization measurements and by electron, x-ray, and neutron diffraction studies

    SciTech Connect (OSTI)

    Daoud-Aladine, A.; Chapon, L. C.; Knight, K. S.; Martin, C.; Hervieu, M.; Brunelli, M.; Radaelli, P. G.

    2007-03-01

    The structural and magnetic properties of the hexagonal four-layer form of SrMnO{sub 3} have been investigated by combining magnetization measurements, electron diffraction, and high-resolution synchrotron x-ray and neutron powder diffraction. Below 350 K, there is subtle structural phase transition from hexagonal symmetry (space group P6{sub 3}/mmc) to orthorhombic symmetry (space group C222{sub 1}) where the hexagonal metric is preserved. The second-order phase transition involves a slight tilting of the corner-sharing Mn{sub 2}O{sub 9} units composed of two face-sharing MnO{sub 6} octahedra and the associated displacement of Sr{sup 2+} cations. The phase transition is described in terms of symmetry-adapted displacement modes of the high symmetry phase. Upon further cooling, long range magnetic order with propagation vector k=(0,0,0) sets in below 300 K. The antiferromagnetic structure, analyzed using representation theory, shows a considerably reduced magnetic moment indicating the crucial role played by direct exchange between Mn centers of the Mn{sub 2}O{sub 9} units.

  17. Operando Lithium Dynamics in the Li-Rich Layered Oxide Cathode Material via Neutron Diffraction

    DOE PAGES-Beta [OSTI]

    Liu, Haodong; An, Ke; Venkatachalam, Subramanian; Qian, Danna; Zhang, Minghao; Meng, Ying Shirley

    2016-04-06

    Neutron diffraction under operando battery cycling is used to study the lithium and oxygen dynamics of high Li-rich Li(Lix/3Ni(3/8-3x/8)Co(1/4-x/4)Mn(3/8+7x/24)O2 (x = 0.6, HLR) and low Li-rich Li(Lix/3Ni(1/3-x/3)Co(1/3-x/3)Mn(1/3+x/3)O2 (x = 0.24, LLR) compounds that exhibit different degrees of oxygen activation at high voltage. The measured lattice parameter changes and oxygen position show largely contrasting changes for the two cathodes where the LLR exhibits larger movement of oxygen and lattice contractions in comparison to the HLR that maintains relatively constant lattice parameters and oxygen position during the high voltage plateau until the end of charge. Density functional theory calculations show the presencemore » of oxygen vacancy during the high voltage plateau; changes in the lattice parameters and oxygen position are consistent with experimental observations. Lithium migration kinetics for the Li-rich material is observed under operando conditions for the first time to reveal the rate of lithium extraction from the lithium layer, and transition metal layer is related to the different charge and discharge characteristics. At the beginning of charging, the lithium extraction predominately occurs within the lithium layer. The lithium extraction from the lithium layer slows down and extraction from the transition metal layer evolves at a faster rate once the high voltage plateau is reached.« less

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

    SciTech Connect (OSTI)

    Thompson, Corey; Greedan, John; Garlea, Vasile O; Flacau, Roxana; Tan, Malinda; Derakhshan, Shahab

    2014-01-01

    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

  19. The Manuel Lujan, Jr. Neutron Scattering Center LANSCE experiment reports 1989 run cycle

    SciTech Connect (OSTI)

    Hyer, D.K.; DiStravolo, M.A.

    1990-10-01

    This report contains a listing and description of experiments carried on at the LANSCE neutron scattering facility in the following areas: High Density Powder Diffraction; Neutron Powder Diffractometer, (NPD); Single Crystal Diffractometer, (SCD); Low-Q Diffractometer, (LQD); Surface Profile Analysis Reflectometer, (SPEAR); Filter Difference Spectrometer, (FDS); and Constant-Q Spectrometer.

  20. SSRL Powder Diffraction Workshop

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    Date: Wed., 21st Oct. 1998 Speakers: Apurva Mehta (SSRl) Dave Cox (NSLSBNL) Richard Harlow (E. I. DuPont de Nemours & Co.) Poul Norby (University of Aarhus) Larry Finger ...

  1. Extracting grain-orientation-dependent data from in situ time-of-flight neutron diffraction. I. Inverse pole figures

    DOE PAGES-Beta [OSTI]

    Stoica, Grigoreta M.; Stoica, Alexandru Dan; An, Ke; Ma, Dong; Vogel, S. C.; Carpenter, J. S.; Wang, Xun-Li

    2014-11-28

    The problem of calculating the inverse pole figure (IPF) is analyzed from the perspective of the application of time-of flight neutron diffraction toin situmonitoring of the thermomechanical behavior of engineering materials. On the basis of a quasi-Monte Carlo (QMC) method, a consistent set of grain orientations is generated and used to compute the weighting factors for IPF normalization. The weighting factors are instrument dependent and were calculated for the engineering materials diffractometer VULCAN (Spallation Neutron Source, Oak Ridge National Laboratory). The QMC method is applied to face-centered cubic structures and can be easily extended to other crystallographic symmetries. Examples includemore » 316LN stainless steelin situloaded in tension at room temperature and an Al–2%Mg alloy, substantially deformed by cold rolling and in situannealed up to 653 K.« less

  2. Anisotropic lattice thermal expansion of PbFeBO4: A study by X-ray and neutron diffraction, Raman spectroscopy and DFT calculations

    DOE PAGES-Beta [OSTI]

    Murshed, M. Mangir; Mendive, Cecilia B.; Curti, Mariano; Nénert, Gwilherm; Kalita, Patricia E.; Lipinska, Kris; Cornelius, Andrew L.; Huq, Ashfia; Gesing, Thorsten M.

    2014-11-01

    We present the lattice thermal expansion of mullite-type PbFeBO4 in this study. The thermal expansion coefficients of the metric parameters were obtained from composite data collected from temperature-dependent neutron and X-ray powder diffraction between 10 K and 700 K. The volume thermal expansion was modeled using extended Grüneisen first-order approximation to the zero-pressure equation of state. The additive frame of the model includes harmonic, quasi-harmonic and intrinsic anharmonic potentials to describe the change of the internal energy as a function of temperature. Moreover, the unit-cell volume at zero-pressure and 0 K was optimized during the DFT simulations. Harmonic frequencies ofmore » the optical Raman modes at the Γ-point of the Brillouin zone at 0 K were also calculated by DFT, which help to assign and crosscheck the experimental frequencies. The low-temperature Raman spectra showed significant anomaly in the antiferromagnetic regions, leading to softening or hardening of some phonons. Selected modes were analyzed using a modified Klemens model. The shift of the frequencies and the broadening of the line-widths helped to understand the anharmonic vibrational behaviors of the PbO4, FeO6 and BO3 polyhedra as a function of temperature.« less

  3. Anisotropic lattice thermal expansion of PbFeBO4: A study by X-ray and neutron diffraction, Raman spectroscopy and DFT calculations

    SciTech Connect (OSTI)

    Murshed, M. Mangir; Mendive, Cecilia B.; Curti, Mariano; Nénert, Gwilherm; Kalita, Patricia E.; Lipinska, Kris; Cornelius, Andrew L.; Huq, Ashfia; Gesing, Thorsten M.

    2014-11-01

    We present the lattice thermal expansion of mullite-type PbFeBO4 in this study. The thermal expansion coefficients of the metric parameters were obtained from composite data collected from temperature-dependent neutron and X-ray powder diffraction between 10 K and 700 K. The volume thermal expansion was modeled using extended Grüneisen first-order approximation to the zero-pressure equation of state. The additive frame of the model includes harmonic, quasi-harmonic and intrinsic anharmonic potentials to describe the change of the internal energy as a function of temperature. Moreover, the unit-cell volume at zero-pressure and 0 K was optimized during the DFT simulations. Harmonic frequencies of the optical Raman modes at the Γ-point of the Brillouin zone at 0 K were also calculated by DFT, which help to assign and crosscheck the experimental frequencies. The low-temperature Raman spectra showed significant anomaly in the antiferromagnetic regions, leading to softening or hardening of some phonons. Selected modes were analyzed using a modified Klemens model. The shift of the frequencies and the broadening of the line-widths helped to understand the anharmonic vibrational behaviors of the PbO4, FeO6 and BO3 polyhedra as a function of temperature.

  4. Neutron diffraction study and magnetotransport properties of stoichiometric CaMoO{sub 3} perovskite prepared by a soft-chemistry route

    SciTech Connect (OSTI)

    Calle, C. de la . E-mail: c.delacalle@icmm.csic.es; Alonso, J.A. . E-mail: ja.alonso@icmm.csic.es; Garcia-Hernandez, M.; Pomjakushin, V.

    2006-06-15

    Polycrystalline CaMoO{sub 3} perovskite has been prepared by soft-chemistry procedures, followed by controlled annealing under reducing conditions (H{sub 2}/N{sub 2} flow). The crystal structure, studied from neutron powder diffraction data, can be described in an orthorhombic unit cell, space group Pbnm (No. 62). The lattice parameters were a=5.4510(1) A, b=5.5821(1) A and c=7.7803(2) A. In the perovskite network the MoO{sub 6} octahedra are tilted by 13.5 deg. in order to optimize the Ca-O bond lengths; the tilting scheme corresponds to a GdFeO{sub 3}-like superstructure. The perovskite is fully oxygen stoichiometric, as demonstrated from the refinement of the oxygen occupancy factors. Resistivity and transport measurements indicated that CaMoO{sub 3} behaves as a metal; at low temperatures (5 K) a small positive magnetoresistance is observed, reaching a maximum value of 1.4% at 9 T. The magnetic susceptibility is predominantly Pauli paramagnetic-like, although a non-negligible temperature-dependent component due to isolated Mo{sup 4+} spins is patent at low temperatures. - Graphical abstract: CaMoO{sub 3} is an orthorhombic perovskite (Pbnm) where the MoO{sub 6} octahedra are tilted by 13.5 deg. (a). It is a Pauli paramagnet (b) and at low temperatures (5 K) presents a small positive magnetoresistance (c)

  5. Neutron diffraction studies on chemical and magnetic structure of multiferroic PbFe{sub 0.67}W{sub 0.33}O{sub 3}

    SciTech Connect (OSTI)

    Matteppanavar, Shidaling Angadi, Basavaraj; Rayaprol, Sudhindra

    2014-04-24

    We report on the single phase synthesis and room temperature structural characterization of PbFe{sub 0.67}W{sub 0.33}O{sub 3} (PFW) multiferroic. The PFW was synthesized by low temperature sintering, Columbite method. Analysis of powder XRD pattern exhibits single phase formation of PFW with no traces of pyrochlore phase. Detailed analysis of room temperature neutron diffraction (ND) reveals cubic phase at room temperature, space group Pm-3m. The ND pattern clearly reveals magnetic Bragg peak at 2? = 18.51 (Q = 1.36{sup ?1}). The refinement of magnetic structure reveals G-type antiferromagnetic structure in PFW at room temperature. The dielectric constant and loss tangent decreases with increasing frequency. The room temperature P-E measurements shows a non-linear slim hysteresis, typical nature of relaxor multiferroics, with saturation and remnant polarizations of P{sub s} = 1.50 ?C/cm{sup 2} and P{sub r} = 0.40 ?C/cm{sup 2}, respectively.

  6. Neutron diffraction and scattering study on M/sub x/WO/sub 3/ (M=Rb and K)

    SciTech Connect (OSTI)

    Sato, M.; Fujishita, H.; Moodenbaugh, A.R.; Hoshino, S.; Grier, B.H.

    1982-01-01

    To study the relationship between the lattice instability and the superconductivity of nonstoichiometric hexagonal tungsten bronze, M/sub x/WO/sub 3/, neutron diffraction and scattering studies were made. Two types of the structural phase transitions were observed. One is associated with the distortion of the corner linked WO/sub 6/ octahedra. The other is associated with the ordering of the M atoms which partially fill the sites in the WO/sub 3/ cage. A long period modulation of the structure appears for some values of x at low temperature. The discussion on the x dependence of the superconducting transition temperature is presented.

  7. α-Phase transformation kinetics of U – 8 wt% Mo established by in situ neutron diffraction

    DOE PAGES-Beta [OSTI]

    Garlea, Elena; Steiner, M. A.; Calhoun, C. A.; Klein, R. W.; An, K.; Agnew, S. R.

    2016-05-08

    The α-phase transformation kinetics of as-cast U - 8 wt% Mo below the eutectoid temperature have been established by in situ neutron diffraction. α-phase weight fraction data acquired through Rietveld refinement at five different isothermal hold temperatures can be modeled accurately utilizing a simple Johnson-Mehl-Avrami-Kolmogorov impingement-based theory, and the results are validated by a corresponding evolution in the γ-phase lattice parameter during transformation that follows Vegard’s law. Neutron diffraction data is used to produce a detailed Time-Temperature-Transformation diagram that improves upon inconsistencies in the current literature, exhibiting a minimum transformation start time of 40 min at temperatures between 500 °Cmore » and 510 °C. Lastly, the transformation kinetics of U – 8 wt% Mo can vary significantly from as-cast conditions after extensive heat treatments, due to homogenization of the typical dendritic microstructure which possesses non-negligible solute segregation.« less

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

    DOE PAGES-Beta [OSTI]

    Thomas, Sarah A.; Montgomery, Jeffrey M.; Tsoi, Georgiy M.; Vohra, Yogesh K.; Chesnut, Gary N.; Weir, Samuel T.; Tulk, Christopher A.; dos Santos, Antonio M.

    2013-06-11

    Neutron diffraction and electrical transport measurements have been carried out on the heavy rare earth metal terbium at high pressures and low temperatures in order to elucidate the onset of ferromagnetic order as a function of pressure. The electrical resistance measurements show a change in slope as the temperature is lowered through the ferromagnetic Curie temperature. The temperature of this ferromagnetic transition decreases from approximately 240 K at ambient pressure at a rate of –16.7 K/GPa up to a pressure of 3.6 GPa, at which point the onset of ferromagnetic order is suppressed. Neutron diffraction measurements as a function ofmore » pressure at temperatures ranging from 90 K to 290 K confirm that the change of slope in the resistance is associated with the ferromagnetic ordering, since this occurs at pressures similar to those determined from the resistance results at these temperatures. Furthermore, a change in ferromagnetic ordering as the pressure is increased above 3.6 GPa is correlated with the phase transition from the ambient hexagonal close packed (hcp) structure to an α-Sm type structure at high pressures.« less

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

    SciTech Connect (OSTI)

    Thomas, Sarah A.; Montgomery, Jeffrey M.; Tsoi, Georgiy M.; Vohra, Yogesh K.; Chesnut, Gary N.; Weir, Samuel T.; Tulk, Christopher A.; dos Santos, Antonio M.

    2013-06-11

    Neutron diffraction and electrical transport measurements have been carried out on the heavy rare earth metal terbium at high pressures and low temperatures in order to elucidate the onset of ferromagnetic order as a function of pressure. The electrical resistance measurements show a change in slope as the temperature is lowered through the ferromagnetic Curie temperature. The temperature of this ferromagnetic transition decreases from approximately 240 K at ambient pressure at a rate of –16.7 K/GPa up to a pressure of 3.6 GPa, at which point the onset of ferromagnetic order is suppressed. Neutron diffraction measurements as a function of pressure at temperatures ranging from 90 K to 290 K confirm that the change of slope in the resistance is associated with the ferromagnetic ordering, since this occurs at pressures similar to those determined from the resistance results at these temperatures. Furthermore, a change in ferromagnetic ordering as the pressure is increased above 3.6 GPa is correlated with the phase transition from the ambient hexagonal close packed (hcp) structure to an α-Sm type structure at high pressures.

  10. Structure of 2 molar NaOH in aqueous solution from neutron diffraction and empirical potential structure refinement

    SciTech Connect (OSTI)

    McLain, Sylvia E.; Imberti, Silvia; Soper, Alan K.; Botti, Alberto; Bruni, Fabio; Ricci, Maria Antonietta

    2006-09-01

    Neutron diffraction with isotopic substitution has been used to investigate aqueous solutions of 2M NaOH in the liquid state. The data were modeled using empirical potential structure refinement which allows for the extraction of the ion-water and water-water correlations. The data show that the ion-water radial distribution functions are in accordance with those found by previous studies on NaOH solutions and follow a trend which is dependent on the concentration of the solute. In particular, the shape of the hydroxide hydration shell is found to be concentration independent, but the number of water molecules occupying this shell increases with dilution. Additionally, the water-water correlations show that there is still a measurable effect on water structure with the addition of ions at this concentration, as the second shell in the water oxygen radial distribution function is compressed relative to the first shell. The data are also used to discuss the recent claims that the published radial distribution functions of water are unreliable, showing that data taken at different neutron sources, with different diffraction geometry and systematic errors lead to the same structural information when analyzed via a realistic modeling regime.

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

    SciTech Connect (OSTI)

    Chen, Yan; Yang, Ling; Ren, Fei; An, Ke

    2014-01-01

    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.

  12. Expanding Lorentz and spectrum corrections to large volumes of reciprocal space, for single crystal TOF neutron diffraction

    DOE PAGES-Beta [OSTI]

    Michels-Clark, Tara M; Savici, Andrei T; Lynch, Vickie E; Hoffmann, Christina; Wang, Xiaoping

    2016-01-01

    Evidence is mounting that potentially exploitable properties of technologically and chemically interesting crystalline materials are often attributed to local structure effects, which can be observed as modulated diffuse scattering (mDS) next to Bragg diffraction (BD). BD forms a regular, sparse grid of discrete points in diffraction space; traditionally, the information in each Bragg peak is extracted first by integration, followed by the application of the required corrections. In contrast, mDS covers expansive volumes of reciprocal space close to, or between, Bragg reflections. For a full measurement of the diffuse scattering, multiple instrument configurations might be required, and the same pointmore » might be measured multiple times. The common integration method is not sufficient and a new, inclusive correction-plus-intensity-extraction method is in demand. In this contribution we introduce a comprehensive data analysis approach to correct and scale the full volume of scattering data in one step. Hence, we explore data treatment and data correction that includes the complete, collected reciprocal space simultaneously, using neutron time of flight (TOF) or wavelength-resolved data, collected at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory.« less

  13. Investigation of phase evolution of CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) by in situ synchrotron high-temperature powder diffraction

    SciTech Connect (OSTI)

    Ouyang, Xin; Huang, Saifang; Zhang, Weijun; Cao, Peng; Huang, Zhaohui; Gao, Wei

    2014-03-15

    In situ synchrotron X-ray powder diffraction was used to study the high-temperature phase evolution of CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) precursors prepared via solid-state and sol–gel methods. After the precursors are heated to 1225 °C, the CCTO phase is the main phase observed in the calcined powder, with the presence of some minor impurities. Comparing the two precursors, we found that the onset temperature for the CCTO phase formation is 800 °C in the sol–gel precursor, lower than that in the solid-state precursor (875 °C). Intermediate phases were only observed in the sol–gel precursor. Both precursors are able to be calcined to sub-micrometric sized powders. Based on the synchrotron data along with differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), the phase formation sequence and mechanism during calcination are proposed in this study. -- Graphical abstract: The in situ synchrotron HT-XRD patterns of CCTO sol–gel and solid-state precursor. Highlights: • Phase formation sequence/mechanism in two CCTO precursors has been established. • Formation temperature of CCTO via sol–gel method is lower than solid-state method. • Intermediate phases are only observed in the sol–gel precursor. • Both precursors are able to be calcined into sub-micrometric sized powders.

  14. Deuterium sites in the defect pyrochlore DTaWO/sub 6/: location from neutron power-diffraction data

    SciTech Connect (OSTI)

    Rotella, F.J.; Jorgensen, J.D.; Morosin, B.; Biefeld, R.M.

    1981-01-01

    Time-of-flight Rietveld refinement and Fourier synthesis of high-resolution powder diffraction data from DTaWO/sub 6/ led to the location of deuterium in partially occupied 48f sites of Fd3m (origin at 3m) as distances of 1.024(9) A at 300/sup 0/K and 1.021(10) A at 12/sup 0/K from each oxygen position. The deuterium sites form spirals in the interconnecting open channels parallel to (110) directions with distances between nearest neighbors of 2.653(2) A at 300/sup 0/K and 2.652(2) A at 12/sup 0/K. These results are consistent with both classical hopping and tunneling models of deuteron transport in this system.

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

    SciTech Connect (OSTI)

    Jacobsen, Matthew K.; Ridley, Christopher J.; Bocian, Artur; Kamenev, Konstantin V.; Kirichek, Oleg; Manuel, Pascal; Khalyavin, Dmitry; Azuma, Masaki; Attfield, J. Paul

    2014-04-15

    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.

  16. Neutron diffraction study of the magnetic-field-induced transition in Mn{sub 3}GaC

    SciTech Connect (OSTI)

    akir, .; Acet, M.; Farle, M.; Senyshyn, A.

    2014-01-28

    The antiperovskite Mn{sub 3}GaC undergoes an isostructural cubiccubic first order transition from a low-temperature, large-cell-volume antiferromagnetic state to a high-temperature, small-cell-volume ferromagnetic state at around 160?K. The transition can also be induced by applying a magnetic field. We study here the isothermal magnetic-field-evolution of the transition as ferromagnetism is stabilized at the expense of antiferromagnetism. We make use of the presence of the two distinct cell volumes of the two magnetic states as a probe to observe by neutron diffraction the evolution of the transition, as the external magnetic field carries the system from the antiferromagnetic to the ferromagnetic state. We show that the large-volume antiferromagnetic and the small-volume ferromagnetic states coexist in the temperature range of the transition. The ferromagnetic state is progressively stabilized as the field increases.

  17. In-situ observation of inhomogeneous degradation in large format Li-ion cells by neutron diffraction

    SciTech Connect (OSTI)

    Cai, Lu; An, Ke; Feng, Zhili; Liang, Chengdu; Harris, Stephen J.

    2013-08-01

    This work presents a non-destructive in-situ method for probing degradation mechanisms in large format, operating, commercial lithium-ion batteries by neutron diffraction. A fresh battery (15 Ah capacity) was shown to have a uniform (homogeneous) local state of charge (SOC) at 4.0 V (9 Ah SOC) and 4.2 V (15 Ah SOC), with 1.33 C and 2.67 C charging rates, respectively. This battery was then aggressively cycled until it retained only a 9 Ah capacity, 60% of its original value. Inhomogeneous deterioration in the battery was observed: near the edges, both the graphite anode and the spinel-based cathode showed a significant loss of capacity, while near the central area, both electrodes functioned properly. An SOC mapping measurement of the degraded battery in the fully charged state (4.2 V) indicated that the loss of local capacity of the anode and cathode is coupled.

  18. Neutron diffraction study on very high elastic strain of 6% in an Fe{sub 3}Pt under compressive stress

    SciTech Connect (OSTI)

    Yamaguchi, Takashi; Fukuda, Takashi Kakeshita, Tomoyuki; Harjo, Stefanus; Nakamoto, Tatsushi

    2014-06-09

    An Fe{sub 3}Pt alloy with degree of order 0.75 exhibits a second-order-like martensitic transformation from a cubic structure to a tetragonal one at about 90?K; its tetragonality c/a changes nearly continuously from 1 to 0.945 on cooling from 90?K to 14?K. We have investigated the change in lattice parameters in a single crystal of the Fe{sub 3}Pt alloy at 93?K under compressive stresses, ?, applied in the [001] direction by neutron diffraction. The tetragonality c/a has decreased continuously from 1 to 0.907 with an increase in |?| up to |?|?=?280?MPa; the corresponding lattice strain in the [001] direction, due to the continuous structure change, increases from 0% to 6.1%. When the stress of 300?MPa is reached, c/a has changed abruptly from 0.907 to 0.789 due to a first-order martensitic transformation.

  19. In-situ neutron diffraction of LaCoO{sub 3} perovskite under uniaxial compression. II. Elastic properties

    SciTech Connect (OSTI)

    Lugovy, Mykola; Aman, Amjad; Orlovskaya, Nina; Chen, Yan; Kuebler, Jakob; Graule, Thomas; Reece, Michael J.; Ma, Dong; Stoica, Alexandru D.; An, Ke

    2014-07-07

    Calculations of elastic constants and development of elastic anisotropy under uniaxial compression in originally isotropic polycrystalline LaCoO{sub 3} perovskite are reported. The lattice strains in individual (hkl) planes as well as average lattice strain were determined both for planes oriented perpendicular and parallel to the loading direction using in-situ neutron diffraction. Utilizing average lattice strains as well as lattice strains along the a and c crystallographic directions, an attempt was made to determine Poisson's ratio of LaCoO{sub 3}, which was then compared with that measured using an impulse excitation technique. The elastic constants were calculated and Young's moduli of LaCoO{sub 3} single crystal in different crystallographic directions were estimated.

  20. Investigation of the structure of C{sub 60} fullerene halides by the neutron and synchrotron diffraction methods

    SciTech Connect (OSTI)

    Troyanov, S. I.

    2006-10-15

    The crystal and molecular structures of bromofullerenes and chlorofullerenes, namely, C{sub 60}Br{sub 6} . 0.5PhCl . 0.5Br{sub 2}, C{sub 60}Br{sub 8} . TiBr{sub 4} . Br{sub 2}, C{sub 60}Br{sub 24} . Br{sub 2}, and C{sub 60}Cl{sub 24} . TiCl{sub 4}, are determined and refined using neutron and synchrotron diffraction. The interatomic distances are determined with an accuracy higher than the accuracy in the determination of the corresponding parameters for the same molecular structures with the use of X-ray laboratory equipment.

  1. Neutron diffraction and thermoelectric properties of indium filled In x Co 4 Sb 12 ( x=0.05, 0.2) and indium cerium filled Ce 0.05 In 0.1 Co 4 Sb 12 skutterudites: Neutron diffraction and thermoelectric properties of In/Ce skutterudites

    DOE PAGES-Beta [OSTI]

    Sesselmann, Andreas; Klobes, Benedikt; Dasgupta, Titas; Gourdon, Olivier; Hermann, Raphael; Mueller, Eckhard

    2015-09-25

    The thermoelectric properties on polycrystalline single (In) and double filled (Ce, In) skutterudites are characterized between 300 and 700 K. Powder neutron diffraction measurements of the skutterudite compositions InxCo4Sb12 (x= 0.05, 0.2) and Ce0.05In0.1Co4Sb12 as a function of temperature (12- 300 K) were carried out, which gives more insight into the structural data of single and double-filled skutterudites. Our results show that due to the annealing treatment, a Sb deficiency is detectable and thus verifies defects at the Sb lattice site of the skutterudite. Furthermore, we show by electron microprobe analysis that a considerable amount of indium is lost duringmore » synthesis and post-processing for the single indium filled samples, but not for the double cerium and indium skutterudite sample. The double-filled skutterudite is superior to the single-filled skutterudite composition due to a higher charge carrier density, a comparable lattice thermal resistivity, and a higher density of states effective mass in our experiment. Finally, we obtained a significantly higher Einstein temperature for the double-filled skutterudite composition in comparison to the single-filled species, which reflects the high sensitivity due to filling of the void lattice position within the skutterudite crystal.« less

  2. Solid solubilities of (La Nd,){sub 2}(Zr,Ti){sub 2}O{sub 7} phases deduced by neutron diffraction

    SciTech Connect (OSTI)

    Harvey, Elizabeth J.; Whittle, Karl R.; Lumpkin, Gregory R.; Smith, Ronald I.; Redfern, Simon A.T. . E-mail: satr@cam.ac.uk

    2005-03-15

    Time-of-flight powder neutron diffraction has been performed on oxides with composition (La{sub 1-x}Nd{sub x}){sub 2}Zr{sub 2}O{sub 7} and Nd{sub 2}(Zr{sub 1-x}Ti{sub x}){sub 2}O{sub 7}, where x=0, 0.2, 0.4,...1.0, in order to determine the solid solution behaviour across each series. Between La{sub 2}Zr{sub 2}O{sub 7} and Nd{sub 2}Zr{sub 2}O{sub 7}, a cubic pyrochlore phase is observed (Fd3-bar m, Z=8). A linear decrease in the lattice parameter from 10.8047 to 10.6758A indicates complete miscibility of the two end-members. For the same series, the 48f oxygen x-parameter increases from 0.3313 to 0.3348, suggesting increased distortion of the 6 coordinate B sites and reduced distortion of the 8 coordinate A sites. There is limited solubility of Nd{sub 2}Ti{sub 2}O{sub 7} in Nd{sub 2}Zr{sub 2}O{sub 7}. Exsolution of a monoclinic phase (P2{sub 1}, Z=8) rich in Nd{sub 2}Ti{sub 2}O{sub 7} is observed at approximately x=0.56. The compositional range over which a solid solution exists is more extensive than that which has been previously reported. The solubility of Nd{sub 2}Zr{sub 2}O{sub 7} in Nd{sub 2}Ti{sub 2}O{sub 7} is very low.

  3. Anisotropic lattice thermal expansion of PbFeBO{sub 4}: A study by X-ray and neutron diffraction, Raman spectroscopy and DFT calculations

    SciTech Connect (OSTI)

    Murshed, M. Mangir; Mendive, Cecilia B.; Curti, Mariano; Nénert, Gwilherm; Kalita, Patricia E.; Lipinska, Kris; Cornelius, Andrew L.; Huq, Ashfia; Gesing, Thorsten M.

    2014-11-15

    Highlights: • Mullite-type PbFeBO{sub 4} shows uni-axial negative coefficient of thermal expansion. • Anisotropic thermal expansion of the metric parameters was modeled using modified Grüneisen approximation. • The model includes harmonic, quasi-harmonic and intrinsic anharmonic contributions to the internal energy. • DFT calculation, temperature- and pressure-dependent Raman spectra help understand the phonon decay and associated anharmonicity. - Abstract: The lattice thermal expansion of mullite-type PbFeBO{sub 4} is presented in this study. The thermal expansion coefficients of the metric parameters were obtained from composite data collected from temperature-dependent neutron and X-ray powder diffraction between 10 K and 700 K. The volume thermal expansion was modeled using extended Grüneisen first-order approximation to the zero-pressure equation of state. The additive frame of the model includes harmonic, quasi-harmonic and intrinsic anharmonic potentials to describe the change of the internal energy as a function of temperature. The unit-cell volume at zero-pressure and 0 K was optimized during the DFT simulations. Harmonic frequencies of the optical Raman modes at the Γ-point of the Brillouin zone at 0 K were also calculated by DFT, which help to assign and crosscheck the experimental frequencies. The low-temperature Raman spectra showed significant anomaly in the antiferromagnetic regions, leading to softening or hardening of some phonons. Selected modes were analyzed using a modified Klemens model. The shift of the frequencies and the broadening of the line-widths helped to understand the anharmonic vibrational behaviors of the PbO{sub 4}, FeO{sub 6} and BO{sub 3} polyhedra as a function of temperature.

  4. Single crystal neutron diffraction study of the magnetic structure of TmNi{sub 2}B{sub 2}C

    SciTech Connect (OSTI)

    Sternlieb, B.; Shapiro, S.; Stassis, C.; Goldman, A.I.; Canfield, P.

    1997-02-01

    Neutron diffraction techniques have been used to study the magnetic structure of single crystals of the magnetic superconductor (T{sub c} {congruent} 11K) TmNi{sub 2}B{sub 2}C. We find that below approximately 1.5K the magnetic moments order in an incommensurate spin wave with propagation vector q{sub m} = q{sub m} (a* +b*) (or q{sub m} = q{sub m} (a* + b*)) with q{sub m} = 0.094 {+-} 0.001. The spin wave is transverse with the moments aligned along the c-axis, and the observation of relatively intense higher order harmonics shows that the modulation is not purely sinusoidal but considerably squared. This incommensurate magnetic structure, which coexists with superconductivity below T{sub N} {congruent} 1.5K, is quite different from those observed in the magnetic superconductors HoNi{sub 2}B{sub 2}C and ErNi{sub 2}B{sub 2}C. The origin of diffraction peaks observed in scans parallel to a* is briefly discussed.

  5. Vacancy-induced nanoscale phase separation in KxFe2–ySe₂ single crystals evidenced by Raman scattering and powder x-ray diffraction

    DOE PAGES-Beta [OSTI]

    Lazarević, N.; Abeykoon, M.; Stephens, P. W.; Lei, Hechang; Bozin, E. S.; Petrovic, C.; Popović, Z. V.

    2012-08-06

    Polarized Raman scattering spectra of KxFe2–ySe₂ were analyzed in terms of peculiarities of both I4/m and I4/mmm space group symmetries. The presence of the Raman active modes from both space group symmetries (16 Raman-active modes of the I4/m phase and two Raman-active modes of the I4/mmm phase) confirmed the existence of two crystallographic domains with different space group symmetry in a KxFe2–ySe₂ sample. High-resolution synchrotron powder x-ray diffraction structural refinement of the same sample confirmed the two-phase description, and determined the atomic positions and occupancies for both domains.

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

    SciTech Connect (OSTI)

    Vadlamani, Bhaskar S; An, Ke; Jagannathan, M.; Ravi Chandran, K.

    2014-01-01

    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.

  7. Deformation mechanisms in a precipitation-strengthened ferritic superalloy revealed by in situ neutron diffraction studies at elevated temperatures

    DOE PAGES-Beta [OSTI]

    Huang, Shenyan; Gao, Yanfei; An, Ke; Zheng, Lili; Wu, Wei; Teng, Zhenke; Liaw, Peter K

    2014-10-22

    In this study, the ferritic superalloy Fe–10Ni–6.5Al–10Cr–3.4Mo strengthened by ordered (Ni,Fe)Al B2-type precipitates is a candidate material for ultra-supercritical steam turbine applications above 923 K. Despite earlier success in improving its room-temperature ductility, the creep resistance of this material at high temperatures needs to be further improved, which requires a fundamental understanding of the high-temperature deformation mechanisms at the scales of individual phases and grains. In situ neutron diffraction has been utilized to investigate the lattice strain evolution and the microscopic load-sharing mechanisms during tensile deformation of this ferritic superalloy at elevated temperatures. Finite-element simulations based on the crystal plasticitymore » theory are employed and compared with the experimental results, both qualitatively and quantitatively. Based on these interphase and intergranular load-partitioning studies, it is found that the deformation mechanisms change from dislocation slip to those related to dislocation climb, diffusional flow and possibly grain boundary sliding, below and above 873 K, respectively. Insights into microstructural design for enhancing creep resistance are also discussed.« less

  8. Deformation mechanisms in a precipitation-strengthened ferritic superalloy revealed by in situ neutron diffraction studies at elevated temperatures

    SciTech Connect (OSTI)

    Huang, Shenyan; Gao, Yanfei; An, Ke; Zheng, Lili; Wu, Wei; Teng, Zhenke; Liaw, Peter K

    2014-10-22

    In this study, the ferritic superalloy Fe–10Ni–6.5Al–10Cr–3.4Mo strengthened by ordered (Ni,Fe)Al B2-type precipitates is a candidate material for ultra-supercritical steam turbine applications above 923 K. Despite earlier success in improving its room-temperature ductility, the creep resistance of this material at high temperatures needs to be further improved, which requires a fundamental understanding of the high-temperature deformation mechanisms at the scales of individual phases and grains. In situ neutron diffraction has been utilized to investigate the lattice strain evolution and the microscopic load-sharing mechanisms during tensile deformation of this ferritic superalloy at elevated temperatures. Finite-element simulations based on the crystal plasticity theory are employed and compared with the experimental results, both qualitatively and quantitatively. Based on these interphase and intergranular load-partitioning studies, it is found that the deformation mechanisms change from dislocation slip to those related to dislocation climb, diffusional flow and possibly grain boundary sliding, below and above 873 K, respectively. Insights into microstructural design for enhancing creep resistance are also discussed.

  9. Non destructive neutron diffraction measurements of cavities, inhomogeneities, and residual strain in bronzes of Ghiberti's relief from the Gates of Paradise

    SciTech Connect (OSTI)

    Festa, G.; Senesi, R.; Alessandroni, M.; Andreani, C.; Vitali, G.; Porcinai, S.; Giusti, A. M.; Materna, T.; Paradowska, A. M.

    2011-03-15

    Quantitative neutron studies of cultural heritage objects provide access to microscopic, mesoscopic, and macroscopic structures in a nondestructive manner. In this paper we present a neutron diffraction investigation of a Ghiberti Renaissance gilded bronze relief devoted to the measurement of cavities and inhomogeneities in the bulk of the sample, along with the bulk phase composition and residual strain distribution. The quantitative measurements allowed the determination of the re-melting parts extension, as well as improving current knowledge about the manufacturing process. The study provides significant and unique information to conservators and restorators about the history of the relief.

  10. Lithium insertion properties of Li{sub x}TiNb{sub 2}O{sub 7} investigated by neutron diffraction and first-principles modelling

    SciTech Connect (OSTI)

    Catti, Michele; Pinus, Ilya; Knight, Kevin

    2015-09-15

    TiNb{sub 2}O{sub 7}, a good candidate as anode in lithium batteries, was treated with n-butyllithium to synthesize Li{sub x}TiNb{sub 2}O{sub 7} phases similar to those formed during electrochemical reactions. The Li{sub 2.67}TiNb{sub 2}O{sub 7} and Li{sub 3.33}TiNb{sub 2}O{sub 7} compounds, monoclinic C2/m, were studied by time-of-flight powder neutron diffraction. Their crystal structures, containing 3×3 blocks of (Ti,Nb)O{sub 6} octahedra, were Rietveld refined including Li positions. The Li atoms are distributed in similar amounts over sites with (Li–O) Coordination Numbers 5 and 4, although CN=5 should be preferred for having lower energy. Quantum-mechanical calculations were also performed, determining the average charge–discharge voltages to be 1.415 and 1.571 V for Li{sub 3.33}TiNb{sub 2}O{sub 7} and Li{sub 2.67}TiNb{sub 2}O{sub 7}, respectively, in good agreement with experimental results. An analysis of the theoretical charge distribution shows that, on lithiation, the chemical reduction of Ti and Nb atoms concentrates in the more condensed peripheral octahedra of the 3×3 block. This corresponds to electrons moving into a partly spin-polarized small band which gives rise to semi-metallic conductivity. - Graphical abstract: Structure of monoclinic Li{sub 3.33}TiNb{sub 2}O{sub 7}, and corresponding electron density of states. - Highlights: • Lithium was chemically inserted into the battery anode material TiNb{sub 2}O{sub 7}. • Li atoms are distributed over four- and fivefold oxygen coordinated sites. • On lithiation Nb and Ti atoms are reduced according to a peculiar structural pattern. • Theoretically predicted charge–discharge voltages fit experiments very well.

  11. A short note on physical properties to irradiated nuclear fuel by means of X-ray diffraction and neutron scattering techniques

    SciTech Connect (OSTI)

    Abdullah, Yusof Husain, Hishamuddin; Hak, Cik Rohaida Che; Alias, Nor Hayati; Yusof, Mohd Reusmaazran; Kasim, Norasiah Ab; Zali, Nurazila Mat; Mohamed, Abdul Aziz

    2015-04-29

    For nuclear reactor applications, understanding the evolution of the fuel materials microstructure during irradiation are of great importance. This paper reviews the physical properties of irradiated nuclear fuel analysis which are considered to be of most importance in determining the performance behavior of fuel. X-rays diffraction was recognize as important tool to investigate the phase identification while neutron scattering analyses the interaction between uranium and other materials and also investigation of the defect structure.

  12. Obtaining aluminas from the thermal decomposition of their different precursors: An {sup 27}Al MAS NMR and X-ray powder diffraction studies

    SciTech Connect (OSTI)

    Chagas, L.H.; De Carvalho, G.S.G.; San Gil, R.A.S.; Chiaro, S.S.X.; Leito, A.A.; Diniz, R.

    2014-01-01

    Graphical abstract: - Highlights: We synthesized three precursors of alumina from different methods. The calcination of the precursors generated several alumina polymorphs. XRD and NMR were used for structural investigation of the polymorphs. The synthesis route determines the structural and textural properties of the solids. - Abstract: A commercial sample of Boehmite was used as precursor of alumina polymorphs. For comparison, three other precursors were synthesized from different methods. Particularly, the use of excess of urea promoted a very crystalline form of basic aluminum carbonate. The characteristics of the four precursors were investigated by thermal, vibrational and X-ray powder diffraction (XRD) analysis. Additionally, the nuclear magnetic resonance, with magic angle spinning ({sup 27}Al MAS NMR), was used to verify the coordination of aluminum cations. Each precursor was calcined at various temperatures generating alumina polymorphs, which were structurally analyzed by XRD and {sup 27}Al MAS NMR. Due to interest in catalysis supports, special attention was given to the ?-Al{sub 2}O{sub 3} phase, which in addition to structural investigation was subjected to textural analysis. The results showed that, from different synthesis procedures and common route of calcination, one can obtain materials with the same composition but with different structural and textural properties, which in turn can significantly influence the performance of a supported catalyst.

  13. Neutron diffraction study of the martensitic transformation and chemical order in Heusler alloy Ni1.91Mn1.29Ga0.8

    DOE PAGES-Beta [OSTI]

    Ari-Gur, Pnina; Garlea, Vasile O.; Cao, Huibo; Ge, Y.; Aaltio, I.; Hannula, S. P.; Koledov, V.

    2015-11-05

    In this study, Heusler alloys of Ni-Mn-Ga compositions demonstrate ferromagnetic shape memory effect in the martensitic state. The transformation temperature and the chemical order depend strongly on the composition. In the current work, the structure and chemical order of the martensitic phase of Ni1.91Mn1.29Ga0.8 were studied using neutron diffraction; the diffraction pattern was refined using the FullProf software. It was determined that the structural transition occurs around 330 K. At room temperature, 300 K, which is below the martensite transformation temperature, all the Bragg reflections can be described by a monoclinic lattice with a symmetry of space group P 1more » 2/m 1 and lattice constants of a = 4.23047(7) [Å], b = 5.58333(6) [Å], c = 21.0179(2) [Å], beta = 90.328(1). The chemical order is of critical importance in these alloys, and it was previously studied at 363 K. Analysis of the neutron diffraction in the monoclinic phase shows that the chemical order is maintained during the martensitic transformation.« less

  14. Powder Diffraction Crystallography Instructional Materials

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    to Least-squares Fitting: A mostly descriptive approach A non-rigorous introduction to linear algebra, linear and non-linear least squares and related concepts. Software...

  15. Hidden Superlattice in Tl2(SC6H4S) and Tl2(SeC6H4Se) Solved from Powder X-ray Diffraction

    SciTech Connect (OSTI)

    K Stone; D Turner; M Singh; T Vaid; P Stephens

    2011-12-31

    The crystal structures of the isostructural title compounds poly[({mu}-benzene-1,4-dithiolato)dithallium], Tl{sub 2}(SC{sub 6}H{sub 4}S), and poly[({mu}-benzene-1,4-diselenolato)dithallium], Tl{sub 2}(SeC{sub 6}H{sub 4}Se), were solved by simulated annealing from high-resolution synchrotron X-ray powder diffraction. Rietveld refinements of an initial structure with one formula unit per triclinic cell gave satisfactory agreement with the data, but led to a structure with impossibly close non-bonded contacts. A disordered model was proposed to alleviate this problem, but an alternative supercell structure leads to slightly improved agreement with the data. The isostructural superlattice structures were confirmed for both compounds through additional data collection, with substantially better counting statistics, which revealed the presence of very weak superlattice peaks not previously seen. Overall, each structure contains Tl-S or Tl-Se two-dimensional networks, connected by phenylene bridges. The sulfur (or selenium) coordination sphere around each thallium is a highly distorted square pyramid or a 'see-saw' shape, depending upon how many Tl-S or Tl-Se interactions are considered to be bonds. In addition, the two compounds contain pairs of Tl{sup I} ions that interact through a closed-shell 'thallophilic' interaction: in the sulfur compound there are two inequivalent pairs of Tl atoms with Tl-Tl distances of 3.49 and 3.58 {angstrom}, while in the selenium compound those Tl-Tl interactions are at 3.54 and 3.63 {angstrom}.

  16. Determination of the absolute configuration of (-)-(2R)-succinic-2-d acid by neutron diffraction study: Unambiguous proof of the absolute stereochemistry of the NAD/sup +//NADH interconversion

    SciTech Connect (OSTI)

    Yuan, H.S.H.; Stevens, R.C.; Fujita, S.; Watkins, M.I.; Koetzle, T.F.; Bau, R.

    1988-05-01

    The absolute configuration of the CHD group (D = deuterium) in (-)-(2R)-succinic-2-d acid, as prepared from (-)-(2S,3R)-malic-3-d acid, has been shown unambiguously to be R by the technique of single-crystal neutron diffraction. The optically active cation (+)-phenylethylammonium was used as the chiral reference. The structure of (C/sub 6/H/sub 5/CH/sub 3/CHNH/sub 3/)/sup +/(HOOCCH/sub 2/CHDCOOO)/sup -/ has been studied with x-ray diffraction at room temperature and neutron diffraction at room temperature and neutron diffraction at 100 K. Crystal data from the neutron diffraction analysis of the phenylethylammonium slat of the title compound at 100 K: space group P2/sub 1/; a = 8.407 /angstrom/, b = 8.300 /angstrom/, c = 8.614 /angstrom/, ..beta.. = 91.20/degrees/; unit cell volume = 600.9 /angstrom//sup 3/, Z = 2. The result confirms the stereochemistry of the malate/succinate transformation, as well as the NAD/sup +//NADH interconversion, and demonstrates the usefulness of the single-crystal neutron diffraction method for determining the absolute configuration of molecules having a chiral monodeuteriomethylene group.

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

    SciTech Connect (OSTI)

    Maruyama, Shingo; Anbusathaiah, Varatharajan; Takeuchi, Ichiro; Fennell, Amy; Enderle, Mechthild; Ratcliff, William D.

    2014-11-01

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

  18. Neutron diffraction study of magnetic field induced behavior in the heavy Fermion Ce3Co4Sn13

    SciTech Connect (OSTI)

    Christianson, Andrew D; Goremychkin, E. A.; Gardner, J. S.; Kang, H. J.; Chung, J.-H.; Manuel, P.; Thompson, J. D.; Sarrao, J. L.; Lawrence, J. M.

    2008-01-01

    The specific heat of Ce3Co4Sn13 exhibits a crossover from heavy Fermion behavior with antiferromagnetic correlations at low field to single impurity Kondo behavior above 2 T. We have performed neutron diffraction measurements in magnetic fields up to 6 Tesla on single crystal samples. The (001) position shows a dramatic increase in intensity in field which appears to arise from static polarization of the 4f level and which at 0.14 K also exhibits an anomaly near 2T reflecting the crossover to single impurity behavior.

  19. In-situ neutron diffraction study of martensitic variant redistribution in polycrystalline Ni-Mn-Ga alloy under cyclic thermo-mechanical treatment

    SciTech Connect (OSTI)

    Li, Zongbin; Zou, Naifu; Zhao, Xiang; Zuo, Liang E-mail: yudong.zhang@univ-lorraine.fr; Zhang, Yudong E-mail: yudong.zhang@univ-lorraine.fr; Esling, Claude; Gan, Weimin

    2014-07-14

    The influences of uniaxial compressive stress on martensitic transformation were studied on a polycrystalline Ni-Mn-Ga bulk alloy prepared by directional solidification. Based upon the integrated in-situ neutron diffraction measurements, direct experimental evidence was obtained on the variant redistribution of seven-layered modulated (7M) martensite, triggered by external uniaxial compression during martensitic transformation. Large anisotropic lattice strain, induced by the cyclic thermo-mechanical treatment, has led to the microstructure modification by forming martensitic variants with a strong 〈0 1 0〉{sub 7M} preferential orientation along the loading axis. As a result, the saturation of magnetization became easier to be reached.

  20. Neutron diffraction and thermoelectric properties of indium filled In x Co 4 Sb 12 ( x=0.05, 0.2) and indium cerium filled Ce 0.05 In 0.1 Co 4 Sb 12 skutterudites: Neutron diffraction and thermoelectric properties of In/Ce skutterudites

    SciTech Connect (OSTI)

    Sesselmann, Andreas; Klobes, Benedikt; Dasgupta, Titas; Gourdon, Olivier; Hermann, Raphael; Mueller, Eckhard

    2015-09-25

    The thermoelectric properties on polycrystalline single (In) and double filled (Ce, In) skutterudites are characterized between 300 and 700 K. Powder neutron diffraction measurements of the skutterudite compositions InxCo4Sb12 (x= 0.05, 0.2) and Ce0.05In0.1Co4Sb12 as a function of temperature (12- 300 K) were carried out, which gives more insight into the structural data of single and double-filled skutterudites. Our results show that due to the annealing treatment, a Sb deficiency is detectable and thus verifies defects at the Sb lattice site of the skutterudite. Furthermore, we show by electron microprobe analysis that a considerable amount of indium is lost during synthesis and post-processing for the single indium filled samples, but not for the double cerium and indium skutterudite sample. The double-filled skutterudite is superior to the single-filled skutterudite composition due to a higher charge carrier density, a comparable lattice thermal resistivity, and a higher density of states effective mass in our experiment. Finally, we obtained a significantly higher Einstein temperature for the double-filled skutterudite composition in comparison to the single-filled species, which reflects the high sensitivity due to filling of the void lattice position within the skutterudite crystal.

  1. In-situ neutron diffraction of LaCoO3 perovskite under uniaxial compression. I. Crystal structure analysis and texture development

    SciTech Connect (OSTI)

    Aman, Amjad; Chen, Yan; Lugovy, Mykola; Orlovskaya, Nina; Reece, Michael John; Ma, Dong; Stoica, Alexandru Dan; An, Ke

    2014-01-01

    The dynamics of texture formation, changes in crystal structure and stress accommodation mechanisms are studied in R3c rhombohedral LaCoO3 perovskite during in-situ uniaxial compression experiment by neutron diffraction. The neutron diffraction revealed the complex crystallographic changes causing the texture formation and significant straining along certain crystallographic directions during in-situ compression, which are responsible for the appearance of hysteresis and non-linear ferroelastic deformation in LaCoO3 perovskite. The irreversible strain after the first loading was connected with the appearance of non-recoverable changes in the intensity ratio of certain crystallographic peaks, causing non-reversible texture formation. However in the second loading/unloading cycle the hysteresis loop was closed and no irreversible strain appears after deformation. The significant texture formation is responsible for increase in the Young s modulus of LaCoO3 at high compressive loads, where the reported values of Young s modulus increase from 76 GPa measured at the very beginning of the loading to 194 GPa at 900 MPa applied compressive stress measured at the beginning of the unloading curve.

  2. In-situ neutron diffraction of LaCoO? perovskite under uniaxial compression. I. Crystal structure analysis and texture development

    SciTech Connect (OSTI)

    Aman, Amjad; Orlovskaya, Nina; Chen, Yan; Lugovy, Mykola; Reece, Michael J.; Ma, Dong; Stoica, Alexandru D.; An, Ke

    2014-07-07

    The dynamics of texture formation, changes in crystal structure, and stress accommodation mechanisms have been studied in perovskite-type R3?c rhombohedral LaCoO? during uniaxial compression using in-situ neutron diffraction. The in-situ neutron diffraction revealed the complex crystallographic changes causing the texture formation and significant straining along certain crystallographic directions during compression, which are responsible for the appearance of hysteresis and non-linear ferroelastic deformation in the LaCoO? perovskite. The irreversible strain after the first loading was connected with the appearance of non-recoverable changes in the intensity ratio of certain crystallographic peaks, causing non-reversible texture formation. However, in the second loading/unloading cycle, the hysteresis loop was closed and no further irrecoverable strain appeared after deformation. The significant texture formation is responsible for an increase in the Young's modulus of LaCoO? at high compressive stresses, ranging from 76 GPa at the very beginning of the loading to 194 GPa at 900 MPa at the beginning of the unloading curve.

  3. Single crystal neutron diffraction study of lattice and magnetic structures of 5M modulated Ni2Mn1.14Ga0.86

    SciTech Connect (OSTI)

    Pramanick, Abhijit; Wang, Xiaoping; An, Ke; Stoica, Alexandru Dan; Hoffmann, Christina; Wang, Xun-Li

    2012-01-01

    A comprehensive description of the crystal and magnetic structures of Ni-Mn-Ga magnetic shape memory alloys is important to understand the physical origins of their magnetoelastic properties. These structural details for an off-stoichiometric Ni2Mn1.14Ga0.86 alloy have been obtained from refinement of high-resolution single crystal neutron diffraction data following a (3+1)-dimensional superspace formalism. In particular, the structure adopts a P2/m( 0 )00 (3+1)-D superspace symmetry with the following fundamental lattice parameters: a=4.255(4) , b=5.613(4) , c=4.216(3) , a commensurate periodicity of 5M and a modulation wave vector of . The magnetic moments are aligned along the b-axis. The modulations for atomic site displacements, site occupancies and magnetic moments are elucidated from a (3+1)-D refinement of the neutron diffraction data. In addition to atomic displacements corresponding to shear waves along <110>, distortions of Ni-centric tetrahedra are also evident. Physical interpretations for the different structural distortions and their relationship with magnetic properties are discussed.

  4. Electronically- and crystal-structure-driven magnetic structures and physical properties of RScSb (R = rare earth) compounds. A neutron diffraction, magnetization and heat capacity study

    SciTech Connect (OSTI)

    Ritter, C; Dhar, S K; Kulkarni, R; Provino, A; Paudyal, Durga; Manfrinetti, Pietro; Gschneidner, Karl A

    2014-08-14

    The synthesis of the new equiatomic RScSb ( R = La-Nd, Sm, Gd-Tm, Lu, Y) compounds has been recently reported. These rare earth compounds crystallize in two different crystal structures, adopting the CeScSi-type ( I 4/ mmm) for the lighter R (La-Nd, Sm) and the CeFeSi-type (P4 /nmm) structure for the heavier R ( R = Gd-Tm, Lu, Y). Here we report the results of neutron diffraction, magnetization and heat capacity measurements on some of these compounds ( R = Ce, Pr, Nd, Gd and Tb). Band structure calculations have also been performed on CeScSb and GdScGe (CeScSi-type), and on GdScSb and TbScSb (CeFeSi-type) to compare and understand the exchange interactions in CeScSi and CeFeSi structure types. The neutron diffraction investigation shows that all five compounds order magnetically, with the highest transition temperature of 66 K in TbScSb and the lowest of about 9 K in CeScSb. The magnetic ground state is simple ferromagnetic (τ = [0 0 0]) in CeScSb, as well in NdScSb for 32 >T > 22 K. Below 22 K a second magnetic transition, with propagation vector τ = [¼ ¼ 0], appears in NdScSb. PrScSb has a magnetic structure within, determined by mostly ferromagnetic interactions and antiferromagnetic alignment of the Pr-sites connected through the I-centering ( τ = [1 0 0]). A cycloidal spiral structure with a temperature dependent propagation vector τ = [δ δ ½] is found in TbScSb. The results of magnetization and heat capacity lend support to the main conclusions derived from neutron diffraction. As inferred from a sharp peak in magnetization, GdScSb orders antiferromagnetically at 56 K. First principles calculations show lateral shift of spin split bands towards lower energy from the Fermi level as the CeScSi-type structure changes to the CeFeSi-type structure. This rigid shift may force the system to transform from exchange split ferromagnetic state to the antiferromagnetic state in RScSb compounds (as seen for example in GdScSb and TbScSb) and is proposed to

  5. [Cu32(H)20{S2P(O i Pr)2 }12 ]: The Largest Number of Hydrides Recorded in a Molecular Nanocluster by Neutron Diffraction

    DOE PAGES-Beta [OSTI]

    Dhayal, Rajendra S.; Liao, Jian-Hong; Kahlal, Samia; Wang, Xiaoping; Liu, Yu-Chiao; Chiang, Ming-Hsi; van Zyl, Werner E.; Saillard, Jean-Yves; Liu, C. W.

    2015-04-20

    An air- and moisture-stable nanoscale polyhydrido copper cluster [Cu32(H)20{S2P(O i Pr)2 }12 ] (1H) was synthesized and structurally characterized. The molecular structure of 1H exhibits a hexacapped pseudo-rhombohedral core of 14 Cu atoms sandwiched between two nestlike triangular cupola fragments of (2x9) Cu atoms in an elongated triangular gyrobicupola polyhedron. The discrete Cu32 cluster is stabilized by 12 dithiophosphate ligands and a record number of 20 hydride ligands, which were found by high-resolution neutron diffraction to exhibit tri-, tetra-, and pentacoordinated hydrides in capping and interstitial modes. We conclude that this result was further supported by a density functional theorymore » investigation on the simplified model [Cu32(H)20(S2PH2)12].« less

  6. Expanding Lorentz and spectrum corrections to large volumes of reciprocal space for single-crystal time-of-flight neutron diffraction

    DOE PAGES-Beta [OSTI]

    Michels-Clark, Tara M.; Savici, Andrei T.; Lynch, Vickie E.; Wang, Xiaoping; Hoffmann, Christina M.

    2016-03-01

    Evidence is mounting that potentially exploitable properties of technologically and chemically interesting crystalline materials are often attributable to local structure effects, which can be observed as modulated diffuse scattering (mDS) next to Bragg diffraction (BD). BD forms a regular sparse grid of intense discrete points in reciprocal space. Traditionally, the intensity of each Bragg peak is extracted by integration of each individual reflection first, followed by application of the required corrections. In contrast, mDS is weak and covers expansive volumes of reciprocal space close to, or between, Bragg reflections. For a representative measurement of the diffuse scattering, multiple sample orientationsmore » are generally required, where many points in reciprocal space are measured multiple times and the resulting data are combined. The common post-integration data reduction method is not optimal with regard to counting statistics. A general and inclusive data processing method is needed. In this contribution, a comprehensive data analysis approach is introduced to correct and merge the full volume of scattering data in a single step, while correctly accounting for the statistical weight of the individual measurements. Lastly, development of this new approach required the exploration of a data treatment and correction protocol that includes the entire collected reciprocal space volume, using neutron time-of-flight or wavelength-resolved data collected at TOPAZ at the Spallation Neutron Source at Oak Ridge National Laboratory.« less

  7. Performance improvements of wavelength-shifting-fiber neutron detectors using high-resolution positioning algorithms

    DOE PAGES-Beta [OSTI]

    Wang, C. L.

    2016-05-17

    On the basis of FluoroBancroft linear-algebraic method [S.B. Andersson, Opt. Exp. 16, 18714 (2008)] three highly-resolved positioning methodswere proposed for wavelength-shifting fiber (WLSF) neutron detectors. Using a Gaussian or exponential-decay light-response function (LRF), the non-linear relation of photon-number profiles vs. x-pixels was linearized and neutron positions were determined. The proposed algorithms give an average 0.03-0.08 pixel position error, much smaller than that (0.29 pixel) from a traditional maximum photon algorithm (MPA). The new algorithms result in better detector uniformity, less position misassignment (ghosting), better spatial resolution, and an equivalent or better instrument resolution in powder diffraction than the MPA. Moreover,more » these characters will facilitate broader applications of WLSF detectors at time-of-flight neutron powder diffraction beamlines, including single-crystal diffraction and texture analysis.« less

  8. Schoenborn wins Bau Neutron Award

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    of LANL's Bioenergy and Biome Sciences group, to receive the 2016 Bau Neutron Diffraction Award. The award recognizes exceptional research achievement in neutron...

  9. A study of suppressed formation of low-conductivity phases in doped Li7La3Zr2O12 garnets by in situ neutron diffraction

    DOE PAGES-Beta [OSTI]

    Chen, Yan; Rangasamy, Ezhiylmurugan; dela Cruz, Clarina R.; Liang, Chengdu; An, Ke

    2015-09-28

    Doped Li7La3Zr2O12 garnets, oxide-based solids with good Li+ conductivity and compatibility, show great potential as leading electrolyte material candidates for all-solid-state lithium ion batteries. Still yet, the conductive bulk usually suffers from the presence of secondary phases and the transition towards a low-conductivity tetragonal phase during synthesis. Dopants are designed to stabilize the high-conductive cubic phase and suppress the formation of the low-conductivity phases. In situ neutron diffraction enables a direct observation of the doping effects by monitoring the phase evolutions during garnet synthesis. It reveals the reaction mechanism involving the temporary presence of intermediate phases. The off-stoichiometry due tomore » the liquid Li2CO3 evaporation leads to the residual of the low-conductivity intermediate phase in the as-synthesized bulk. Appropriate doping of an active element may alter the component of the intermediate phases and promote the completion of the reaction. While the dopants aid to stabilize most of the cubic phase, a small amount of tetragonal phase tends to form under a diffusion process. Lastly, the in situ observations provide the guideline of process optimization to suppress the formation of unwanted low-conductivity phases.« less

  10. Neutron Diffraction Measurement of Residual Stresses, Dislocation Density and Texture in Zr-bonded U-10Mo ''Mini'' Fuel Foils and Plates

    SciTech Connect (OSTI)

    Brown, Donald W.; Okuniewski, M. A.; Sisneros, Thomas A.; Clausen, Bjorn; Moore, G. A.; Balogh, L

    2014-08-07

    Aluminum clad monolithic uranium 10 weight percent molybdenum (U-10Mo) fuel plates are being considered for conversion of several research and test nuclear reactors from high-enriched to low-enriched uranium fuel due to the inherently high density of fissile material. Comprehensive neutron diffraction measurements of the evolution of the textures, residual phase stresses, and dislocation densities in the individual phases of the mini-foils throughout several processing steps and following hot-isostatic pressing to the Al cladding, have been completed. Recovery and recrystallization of the bare U-10Mo fuel foil, as indicated by the dislocation density and texture, are observed depending on the state of the material prior to annealing and the duration and temperature of the annealing process. In general, the HIP procedure significantly reduces the dislocation density, but the final state of the clad plate, both texture and dislocation density, depends strongly on the final processing step of the fuel foil. In contrast, the residual stresses in the clad fuel plate do not depend strongly on the final processing step of the bare foil prior to HIP bonding. Rather, the residual stresses are dominated by the thermal expansion mismatch of the constituent materials of the fuel plate.

  11. Magnetic ordering in TbMn{sub 0.5}Cr{sub 0.5}O{sub 3} studied by neutron diffraction and first-principles calculations

    SciTech Connect (OSTI)

    Staruch, M.; Sharma, V.; Ramprasad, R.; Cruz, C. dela; Jain, M.

    2014-07-21

    The structure and magnetic ordering of bulk TbMn{sub 0.5}Cr{sub 0.5}O{sub 3} was revealed through bulk magnetization and neutron diffraction measurements, and first-principles calculations, respectively. G-type antiferromagnetic ordering of Mn{sup 3+} and Cr{sup 3+} moments was observed in the neutron diffraction data below Nel temperature T{sub N}???84?K. In addition, below ?40?K, short-range magnetic ordering was identified correlating to a ferromagnetic component due to the canting of the moments along the c-axis. The spin configuration is consistent with the first-principles calculations. The magnetic structure revealed in the present TbMn{sub 0.5}Cr{sub 0.5}O{sub 3} sample is distinct from that observed for both end members TbMnO{sub 3} and TbCrO{sub 3}.

  12. On the crystal energy and structure of A{sub 2}Ti{sub n}O{sub 2n+1} (A=Li, Na, K) titanates by DFT calculations and neutron diffraction

    SciTech Connect (OSTI)

    Catti, Michele; Pinus, Ilya; Scherillo, Antonella

    2013-09-15

    First-principles quantum-mechanical calculations (CRYSTAL09 code, B3LYP functional) were performed on alkali titanates A{sub 2}Ti{sub n}O{sub 2n+1} with layered structure (n=3,4,6). Monoclinic structural types with unshifted (P2{sub 1}/m) and with shifted (C2/m) layers were considered. Crystal energies and full structural details were obtained for all Li, Na, and K phases. Neutron diffraction data were collected on powder samples of P2{sub 1}/m-Li{sub 2}Ti{sub 3}O{sub 7} (a=9.3146(3), b=3.7522(1), c=7.5447(3) Å, β=97.611(4)°) and C2/m-K{sub 2}Ti{sub 4}O{sub 9} (a=18.2578(8), b=3.79160(9), c=12.0242(4) Å, β=106.459(4)°) and their structures were Rietveld-refined. Computed energies show the P2{sub 1}/m arrangement as favoured over the C2/m one for n=3, and the opposite holds for n=6. In the n=4 case the P2{sub 1}/m configuration is predicted to be more stable for Li and Na, and the C2/m one for K titanates. Analysis of Li–O and K–O crystal-chemical environments from experiment and theory shows that the alkali atom bonding is stabilized/destabilized in the different phases consistently with the energy trend. - Graphical abstract: Display Omitted - Highlights: • The P2{sub 1}/m structure-type is found to be more stable for A{sub 2}Ti{sub 3}O{sub 7} layer titanates. • The C2/m structure-type is found to be more stable for A{sub 2}Ti{sub 6}O{sub 13} layer titanates. • Tetratitanates are predicted to prefer the P2{sub 1}/m (Li and Na) or C2/m (K) structure. • Li–O and K–O bond distances follow a trend consistent with computed phase energies.

  13. Neutron diffraction study of the martensitic transformation and chemical order in Heusler alloy Ni1.91Mn1.29Ga0.8

    SciTech Connect (OSTI)

    Ari-Gur, Pnina; Garlea, Vasile O.; Cao, Huibo; Ge, Y.; Aaltio, I.; Hannula, S. P.; Koledov, V.

    2015-11-05

    In this study, Heusler alloys of Ni-Mn-Ga compositions demonstrate ferromagnetic shape memory effect in the martensitic state. The transformation temperature and the chemical order depend strongly on the composition. In the current work, the structure and chemical order of the martensitic phase of Ni1.91Mn1.29Ga0.8 were studied using neutron diffraction; the diffraction pattern was refined using the FullProf software. It was determined that the structural transition occurs around 330 K. At room temperature, 300 K, which is below the martensite transformation temperature, all the Bragg reflections can be described by a monoclinic lattice with a symmetry of space group P 1 2/m 1 and lattice constants of a = 4.23047(7) [Å], b = 5.58333(6) [Å], c = 21.0179(2) [Å], beta = 90.328(1). The chemical order is of critical importance in these alloys, and it was previously studied at 363 K. Analysis of the neutron diffraction in the monoclinic phase shows that the chemical order is maintained during the martensitic transformation.

  14. Neutron diffraction, Mössbauer effect and electron paramagnetic resonance studies on multiferroic Pb(Fe{sub 2/3}W{sub 1/3})O{sub 3}

    SciTech Connect (OSTI)

    Matteppanavar, Shidaling; Angadi, Basavaraj; Rayaprol, Sudhindra; AV, Anupama; Sahoo, Balaram

    2015-06-24

    Multiferroic Pb(Fe{sub 2/3}W{sub 1/3})O{sub 3} ceramics were synthesized via a modified two-stage Columbite method. Single phase formation was confirmed from the analysis of x-ray and neutron diffraction patterns recorded at room temperature. Structural analysis of the diffraction data reveals cubic phase (space group Pm-3m) for the title compound. Magnetic structure of the title compound at room temperature exhibits G-type antiferromagnetic structure. The Mössbauer spectroscopy and Electron Paramagnetic Resonance (EPR) studies were carried out at 300 K. The isomer shift and quadrupole splitting of the Mössbauer spectra confirms the trivalent state of iron (Fe{sup 3+}). The Mössbauer spectra also suggest that the iron and tungsten are randomly distributed at the octahedral, B site. EPR spectra show a single broad line associated with Fe{sup 3+} ions. Both spectra clearly exhibit weak ferromagnetic behaviour of Pb(Fe{sub 2/3}W{sub 1/3})O{sub 3} ceramic at 300 K. Considering neutron diffraction, Mössbauer and EPR results together, it may be stated here that Pb(Fe{sub 2/3}W{sub 1/3})O{sub 3} exhibits antiferromagnetic behavior along with weak ferromagnetism at room temperature.

  15. Unraveling the Hydrogenation of TiO 2 and Graphene Oxide/TiO 2 Composites in Real Time by in Situ Synchrotron X-ray Powder Diffraction and Pair Distribution Function Analysis

    DOE PAGES-Beta [OSTI]

    Nguyen-Phan, Thuy-Duong; Liu, Zongyuan; Luo, Si; Gamalski, Andrew D.; Vovchok, Dimitry; Xu, Wenqian; Stach, Eric A.; Polyansky, Dmitry E.; Fujita, Etsuko; Rodriguez, José A.; et al

    2016-02-18

    The functionalization of graphene oxide (GO) and graphene by TiO2 and other metal oxides has attracted considerable attention due to numerous promising applications in catalysis, energy conversion, and storage. We propose hydrogenation of this class of materials as a promising way to tune catalytic properties by altering the structural and chemical transformations that occur upon H incorporation. We also investigate the structural changes that occur during the hydrogenation process using in situ powder X-ray diffraction and pair distribution function analysis of GO–TiO2 and TiO2 under H2 reduction. Sequential Rietveld refinement was employed to gain insight into the evolution of crystalmore » growth of TiO2 nanoparticles in the presence of two-dimensional (2D) GO nanosheets. GO sheets not only significantly retarded the nucleation and growth of rutile impurities, stabilizing the anatase structure, but was also partially reduced to hydrogenated graphene by the introduction of atomic hydrogen into the honeycomb lattice. We discuss the hydrogenation processes and the resulting composite structure that occurs during the incorporation of atomic H and the dynamic structural transformations that leads to a highly active photocatalyst.« less

  16. Neutron diffraction study of the crystal structure and structural phase transition of La{sub 0.7}Ca{sub 0.3-x}Sr{sub x}CrO{sub 3} (0<=x<=0.3)

    SciTech Connect (OSTI)

    Omoto, Kazuki; Norberg, Stefan T.; Hull, Steve; Aoto, Akimitsu; Hashimoto, Takuya

    2010-02-15

    The crystal structure of the La{sub 0.7}Ca{sub 0.3-x}Sr{sub x}CrO{sub 3} series, including the compositional and temperature dependence of the structural parameters, has been studied by variable temperature neutron diffraction measurements. The extent of the distortions from the ideal cubic perovskite structure has been evaluated quantitatively using the average bond lengths and the mean volumes of the [CrO{sub 6}] octahedron and [(La/Ca/Sr)O{sub 12}] polyhedron, and has been shown to decrease with increase of Sr content or temperature. At the structural phase transition from the orthorhombic (Pnma) structure to the rhombohedral (R3-barc) one, the volume of the [CrO{sub 6}] octahedron decreases whereas that of the [(La/Ca/Sr)O{sub 12}] polyhedron shows little difference, resulting in an overall decrease in the level of distortion. The change in the degree of distortion at the phase transition decreases with increase of Sr content, in agreement with the smaller variation of the enthalpy and volume for the specimens with higher Sr content. - Graphical abstract: Temperature dependence of parameter, PHI, representing the extent of distortion from the ideal cubic perovskite structure, for La{sub 0.7}Ca{sub 0.3}CrO{sub 3} (diamonds) and La{sub 0.7}Ca{sub 0.15}Sr{sub 0.15}CrO{sub 3} (circles) calculated from neutron diffraction patterns.

  17. FABRICATION OF NEUTRON SOURCES

    DOE Patents [OSTI]

    Birden, J.H.

    1959-01-20

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

  18. A neutron diffraction study and mode analysis of compounds of the system La{sub 1−x}Sr{sub x}FeO{sub 3−x}F{sub x} (x=1, 0.8, 0.5, 0.2) and an investigation of their magnetic properties

    SciTech Connect (OSTI)

    Clemens, Oliver; Berry, Frank J.; Wright, Adrian J.; Knight, Kevin S.; Perez-Mato, J.M.; Igartua, J.M.; Slater, Peter R.

    2013-10-15

    We report here a detailed study of the system La{sub 1−x}Sr{sub x}FeO{sub 3−x}F{sub x}, by neutron powder diffraction- and magnetic-measurements. All the compounds are robust antiferromagnetics with ordering temperatures well above room temperature. Magnetic moments are shown to align parallel to the c-axis. FC-ZFC measurements indicate a small canting of the magnetic moments, resulting in a ferromagnetic component with a maximum for La{sub 0.5}Sr{sub 0.5}FeO{sub 2.5}F{sub 0.5}. We show that the system exhibits a composition-driven transition from a phase, for low fluorination levels (x≤0.5), with Pnma symmetry and the usual system of octahedral tiltings, to a phase with space group Imma for higher fluorine contents, where a correlated distortion of the oxygen octahedra plays a significant role. The consistency of the structural models, with respect to the expected continuity of the amplitudes of the different distortion modes and the invariance of their internal form, was monitored through the symmetry mode decomposition of the structures. - Graphical abstract: The crystal and magnetic structure of La{sub 0.5}Sr{sub 0.5}FeO{sub 2.5}F{sub 0.5}. Display Omitted - Highlights: • The compounds La{sub 1−x}Sr{sub x}FeO{sub 3−x}F{sub x} (x=1, 0.8, 0.5, 0.2) were studied by neutron diffraction. • A mode analysis shows lower symmetry for Sr rich compounds than previously reported. • SrFeO{sub 2}F crystallizes in the orthorhombic space group Imma. • Magnetic moments resulting from canting depend on metric distortion. • The magnetic structure was determined for La{sub 0.5}Sr{sub 0.5}FeO{sub 2.5}F{sub 0.5}.

  19. NEUTRON SHIELDING STRUCTURE

    DOE Patents [OSTI]

    Mattingly, J.T.

    1962-09-25

    A lightweight neutron shielding structure comprises a honeycomb core which is filled with a neutron absorbing powder. The honeycomb core is faced with parallel planar facing sheets to form a lightweight rigid unit. Suitable absorber powders are selected from among the following: B, B/sub 4/C, B/sub 2/O/ sub 3/, CaB/sub 6/, Li/sub 2/CO3, LiOH, LiBO/sub 2/, Li/s ub 2/O. The facing sheets are constructed of a neutron moderating material, so that fast neutrons will be moderated while traversing the facing sheets, and ultimately be absorbed by the absorber powder in the honeycomb. Beryllium is a preferred moderator material for use in the facing sheets. The advantage of the structure is that it combines the rigidity and light weight of a honeycomb construction with the neutron absorption properties of boron and lithium. (AEC)

  20. X-ray diffraction study of BaTiO{sub 3} single crystals before and after fast-neutron irradiation

    SciTech Connect (OSTI)

    Stash, A. I. Ivanov, S. A.; Stefanovich, S. Yu.; Mosunov, A. V.; Boyko, V. M.; Ermakov, V. S.; Korulin, A. V.; Kalyukanov, A. I.; Isakova, N. N.

    2015-09-15

    The neutron irradiation of ferroelectrics is efficiently used to form structural states that cannot be obtained by conventional technologies. To date, the effect of neutron irradiation on the structure and properties of BaTiO{sub 3} has been studied for only ceramic materials. We have considered the influence of fast-neutron irradiation (F = 1 × 10{sup 17} cm{sup −2}) on the structure and properties of BaTiO{sub 3} single crystals for the first time. The structural changes occurring in irradiated BaTiO{sub 3} and their correlation with the behavior of dielectric and nonlinear optical characteristics are analyzed with the aid of a specially developed method for taking into account the experimental correction to diffuse scattering. Neutron irradiation to the aforementioned dose retains the polar structure of the material and only slightly changes atomic displacements. The radiationinduced structural changes occur according to the high-temperature type to form a structure similar to the cubic modification of unirradiated BaTiO{sub 3} crystal.

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

    Open Energy Information (Open El) [EERE & EIA]

    X-ray powder diffraction, which has traditionally been used in geology, environmental science, material science, and engineering to rapidly identify unknown crystalline...

  2. X-Ray Diffraction (XRD) | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    under investigation. X-ray powder diffraction is widely used in geology, environmental science, material science, and engineering to rapidly identify unknown crystalline substances...

  3. Neutron activation analysis system

    DOE Patents [OSTI]

    Taylor, M.C.; Rhodes, J.R.

    1973-12-25

    A neutron activation analysis system for monitoring a generally fluid media, such as slurries, solutions, and fluidized powders, including two separate conduit loops for circulating fluid samples within the range of radiation sources and detectors is described. Associated with the first loop is a neutron source that emits s high flux of slow and thermal neutrons. The second loop employs a fast neutron source, the flux from which is substantially free of thermal neutrons. Adjacent to both loops are gamma counters for spectrographic determination of the fluid constituents. Other gsmma sources and detectors are arranged across a portion of each loop for deterMining the fluid density. (Official Gazette)

  4. FABRICATION OF NEUTRON SOURCES

    DOE Patents [OSTI]

    Birden, J.H.

    1959-04-21

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

  5. Quantum Model of Catalysis Based on a Mobile Proton Revealed by Subatomic X-ray and Neutron Diffraction Studies of h-aldose Reductase

    SciTech Connect (OSTI)

    Blakeley, M. P.; Ruiz, Fredrico; Cachau, Raul; Hazemann, I.; Meilleur, Flora; Mitschler, A.; Ginell, Stephan; Afonine, Pavel; Ventura, Oscar; Cousido-Siah, Alexandra; Haertlein, M.; Joachimiak, Andrzej; Myles, Dean A A; Podjarny, A.

    2008-01-01

    We present results of combined studies of the enzyme human aldose reductase (h-AR, 36 kDa) using single-crystal x-ray data (0.66 Angstroms, 100K; 0.80 Angstroms, 15K; 1.75 Angstroms, 293K), neutron Laue data (2.2 Angstroms, 293K), and quantum mechanical modeling. These complementary techniques unveil the internal organization and mobility of the hydrogen bond network that defines the properties of the catalytic engine, explaining how this promiscuous enzyme overcomes the simultaneous requirements of efficiency and promiscuity offering a general mechanistic view for this class of enzymes.

  6. Phase stability study of Bi{sub 0.15}Sr{sub 0.85-x}Ae{sub x}CoO{sub 3-{delta}} (x = 0 and Ae = Ba{sub 0.28}; Ca{sub 0.17}) perovskites by in-situ neutron diffraction

    SciTech Connect (OSTI)

    Eriksson, A.K.; Eriksson, S.G.; Chapon, L.C.; Knee, C.S.

    2010-12-15

    The oxygen deficient perovskites, Bi{sub 0.15}Sr{sub 0.85-x}Ae{sub x}CoO{sub 3-{delta}}, x = 0 and Ae{sub x} = Ba{sub 0.28}, Ca{sub 0.17}, were studied with in-situ neutron powder diffraction and combined TGA/DSC in order to investigate their behaviour at elevated temperatures in oxidising conditions. The phase stability of the I4/mmm supercell structure adopted by Bi{sub 0.15}Sr{sub 0.85}CoO{sub 3-{delta}} is shown to be dependent on temperature and the oxygen content of the phase, with three structural events, at T {approx} 250, 590 and 880 {sup o}C, detected. The first transition occurs as the perovskite supercell vanishes due to oxygen absorption; the second transition is also associated with oxidation and involves the decomposition of the perovskite phase via an exothermic process to yield a dominant hexagonal phase. Finally, at T {approx} 900 {sup o}C the perovskite phase re-forms. For the Ba and Ca containing materials the decomposition to the hexagonal phase occurs at T {approx} 600 {sup o}C and {approx} 650 {sup o}C respectively. The presence of Ca at the A-site is found to stabilise the I4/mmm supercell structure in the range RT - 650 {sup o}C. The antiferromagnetic to paramagnetic transitions occur at T{sub N} {approx} 250 {sup o}C, T{sub N} {approx} 175 {sup o}C and T{sub N} {approx} 145 {sup o}C for the samples with Ae{sub x} = Ba{sub 0.28}, x = 0 and Ae{sub x} = Ca{sub 0.17}, respectively.

  7. Schoenborn wins Bau Neutron Award

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    Schoenborn wins Bau Neutron Award Schoenborn wins Bau Neutron Award The American Crystallographic Association (ACA) has selected retired Laboratory Senior Fellow Benno Schoenborn to receive the 2016 Bau Neutron Diffraction Award. August 12, 2015 Benno Schoenborn Benno Schoenborn Communications Office (505) 667-7000 Schoenborn is honored for his pioneering research in macromolecular neutron crystallography and the design and development of the neutron crystallography beamline (Protein

  8. Neutron crystallography aids drug design

    U.S. Department of Energy (DOE) all 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 clinical drug in complex with its human target enzyme. October 9, 2012 Rich Marquez The Protein Crystallography Station at the Los Alamos Neutron Science Center, where groundbreaking work in new drug-design methods is underway using neutron diffraction techniques. Contact Nancy Ambrosiano Communications Office (505)

  9. Neutron diffraction study of the magnetic ordering of the Cu sup ++ spins in Nd sub 1. 5 Ba sub 1. 5 Cu sub 3 O sub 6+x

    SciTech Connect (OSTI)

    Moudden, A.H.; Hennion, B. - Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette ); Schweiss, P. - Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette Kernforschungszentrum Karlsruhe GmbH . Inst. fuer Nukleare Festkoerperphysik); Gehring, P.M.; Shirane, G. (Brookhaven National Lab., Upton, NY (

    1991-01-01

    Elastic neutron scattering experiments performed on single crystals of Nd{sub 1.5}Ba{sub 1.5}Cu{sub 3}O{sub 6+y} reveal successive antiferromagnetic (AF) ordering of the Cu{sup ++} spins. The as grown single crystals show an AF structure characterized by a Neel temperature T{sub N1} {approximately} 390K and a magnetic wave vector (1/2 1/2 0) referring to the tetragonal structure of NdBa{sub 2}Cu{sub 3}O{sub 6}. As the temperature is lowered below T{sub N2} {approximately} 150K, a spin reorientation develops and a second AF ordering with (1/2 1/2 1/2) wave vector is stabilized. When the samples are oxygenated the tetragonal symmetry and the Neel temperature T{sub N1} remain unchanged, whereas the spin reorientation at T{sub N2} is suppressed. The results indicate that the Nd/Ba substitution increases the stability of the tetragonal structure upon the oxygen content. This may induce new possibilities of local oxygen ordering that favour the presence of holes in the deficient layer.

  10. Preparation and structural study from neutron diffraction data of Pr{sub 5}Mo{sub 3}O{sub 16}

    SciTech Connect (OSTI)

    Martinez-Lope, M.J.; Alonso, J.A.; Sheptyakov, D.; Pomjakushin, V.

    2010-12-15

    The title compound has been prepared as polycrystalline powder by thermal treatments of mixtures of Pr{sub 6}O{sub 11} and MoO{sub 2} in air. In the literature, an oxide with a composition Pr{sub 2}MoO{sub 6} has been formerly described to present interesting catalytic properties, but its true stoichiometry and crystal structure are reported here for the first time. It is cubic, isostructural with CdTm{sub 4}Mo{sub 3}O{sub 16} (space group Pn-3n, Z=8), with a=11.0897(1) A. The structure contains MoO{sub 4} tetrahedral units, with Mo-O distances of 1.788(2) A, fully long-range ordered with PrO{sub 8} polyhedra; in fact it can be considered as a superstructure of fluorite (M{sub 8}O{sub 16}), containing 32 MO{sub 2} fluorite formulae per unit cell, with a lattice parameter related to that of cubic fluorite (a{sub f}=5.5 A) as a{approx}2a{sub f}. A bond valence study indicates that Mo exhibits a mixed oxidation state between 5+ and 6+ (perhaps accounting for the excellent catalytic properties). One kind of Pr atoms is trivalent whereas the second presents a mixed Pr{sup 3+}-Pr{sup 4+} oxidation state. The similarity of the XRD pattern with that published for Ce{sub 2}MoO{sub 6} suggests that this compound also belongs to the same structural type, with an actual stoichiometry Ce{sub 5}Mo{sub 3}O{sub 16}. -- Graphical Abstract: Formerly formulated as Pr{sub 2}MoO{sub 6}, the title compound is a cubic superstructure of fluorite (a=11.0897(1) A, space group Pn-3n) due to the long-range ordering of PrO{sub 8} scalenohedra and MoO{sub 4} tetrahedral units, showing noticeable shifts of the oxygen positions in order to provide a tetrahedral coordination for Mo ions. A mixed valence Mo{sup 5+}-Mo{sup 6+} is identified, which could account for the excellent catalytic properties of this material. Display Omitted

  11. Incommensurate magnetic ordering in Cu{sub 2}Te{sub 2}O{sub 5}X{sub 2} (X=Cl,Br) studied by single crystal neutron diffraction

    SciTech Connect (OSTI)

    Zaharko, O.; Roennow, H.; Mesot, J.; Crowe, S. J.; Paul, D. McK.; Brown, P. J.; Daoud-Aladine, A.; Meents, A.; Wagner, A.; Prester, M.; Berger, H.

    2006-02-01

    Polarized and unpolarized neutron-diffraction studies have been carried out on single crystals of the coupled spin tetrahedra systems Cu{sub 2}Te{sub 2}O{sub 5}X{sub 2} (X=Cl,Br). A model of the magnetic structure associated with the propagation vectors k{sup '}{sub Cl}{approx_equal}(-0.150,0.422,(1/2)) and k{sup '}{sub Br}{approx_equal}(-0.172,0.356,(1/2)) and stable below T{sub N}=18 K for X=Cl and T{sub N}=11 K for X=Br is proposed. A feature of the model, common to both the bromide and chloride, is a canted coplanar motif for the four Cu{sup 2+} spins on each tetrahedron which rotates on a helix from cell to cell following the propagation vector. The Cu{sup 2+} magnetic moment determined for X=Br,0.395(5){mu}{sub B}, is significantly less than for X=Cl,0.88(1){mu}{sub B} at 2 K. The magnetic structure of the chloride associated with the wave vector k{sup '} differs from that determined previously for the wave vector k{approx_equal}(0.150,0.422,(1/2)) [O. Zaharko et al., Phys. Rev. Lett. 93, 217206(E) (2004)].

  12. In situ neutron scattering study of nanoscale phase evolution in PbTe-PbS thermoelectric material

    DOE PAGES-Beta [OSTI]

    Ren, Fei; Schmidt, Robert; Keum, Jong K.; Qian, Bosen; Case, Eldon D.; Littrell, Ken C.; An, Ke

    2016-08-24

    Introducing nanostructural second phases has been proved to be an effective approach to reduce the lattice thermal conductivity and thus enhance the figure of merit for many thermoelectric materials. Furthermore studies of the formation and evolution of these second phases are central to understanding temperature dependent material behavior, improving thermal stabilities, as well as designing new materials. We examined powder samples of PbTe-PbS thermoelectric material using in situ neutron diffraction and small angle neutron scattering (SANS) techniques from room temperature to elevated temperature up to 663 K, to explore quantitative information on the structure, weight fraction, and size of themore » second phase. Neutron diffraction data showed the as-milled powder was primarily solid solution before heat treatment. During heating, PbS second phase precipitated out of the PbTe matrix around 480 K, while re-dissolution started around 570 K. The second phase remained separated from the matrix upon cooling. Furthermore, SANS data indicated there are two populations of nanostructures. The size of the smaller nanostructure increased from initially 5 nm to approximately 25 nm after annealing at 650 K, while the size of the larger nanostructure remained unchanged. Our study demonstrated that in situ neutron techniques are effective means to obtain quantitative information to study temperature dependent nanostructural behavior of thermoelectrics and likely other high-temperature materials.« less

  13. Energetic powder

    DOE Patents [OSTI]

    Jorgensen, Betty S.; Danen, Wayne C.

    2003-12-23

    Fluoroalkylsilane-coated metal particles. The particles have a central metal core, a buffer layer surrounding the core, and a fluoroalkylsilane layer attached to the buffer layer. The particles may be prepared by combining a chemically reactive fluoroalkylsilane compound with an oxide coated metal particle having a hydroxylated surface. The resulting fluoroalkylsilane layer that coats the particles provides them with excellent resistance to aging. The particles can be blended with oxidant particles to form energetic powder that releases chemical energy when the buffer layer is physically disrupted so that the reductant metal core can react with the oxidant.

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

    Office of Scientific and Technical Information (OSTI)

    In Professor Shull's opinion the most important problem he worked on at the time dealt with determining the positions of hydrogen atoms in materials. "Hydrogen atoms are ubiquitous ...

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

    Office of Scientific and Technical Information (OSTI)

    can then be obtained. Understanding where atoms are in a material and how they interact with one another is the key to understanding a material's properties. "Then we can...

  16. Powder treatment process

    DOE Patents [OSTI]

    Weyand, John D. (Greensburg, PA)

    1988-01-01

    (1) A process comprising spray drying a powder-containing slurry, the slurry containing a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, while reducing the tendency for oxidation of the constituent by including as a liquid constituent of the slurry an organic liquid; (2) a process comprising spray drying a powder-containing slurry, the powder having been pretreated to reduce content of a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, the pretreating comprising heating the powder to react the constituent; and (3) a process comprising reacting ceramic powder, grinding the reacted powder, slurrying the ground powder, spray drying the slurried powder, and blending the dried powder with metal powder.

  17. Powder treatment process

    DOE Patents [OSTI]

    Weyand, J.D.

    1988-02-09

    Disclosed are: (1) a process comprising spray drying a powder-containing slurry, the slurry containing a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, while reducing the tendency for oxidation of the constituent by including as a liquid constituent of the slurry an organic liquid; (2) a process comprising spray drying a powder-containing slurry, the powder having been pretreated to reduce content of a powder constituent susceptible of oxidizing under the temperature conditions of the spray drying, the pretreating comprising heating the powder to react the constituent; and (3) a process comprising reacting ceramic powder, grinding the reacted powder, slurrying the ground powder, spray drying the slurried powder, and blending the dried powder with metal powder. 2 figs.

  18. Powder dispersion system

    DOE Patents [OSTI]

    Gorenz, Heather M.; Brockmann, John E.; Lucero, Daniel A.

    2011-09-20

    A powder dispersion method and apparatus comprising an air eductor and a powder dispensing syringe inserted into a suction connection of the air eductor.

  19. Structural study of (N{sub 2}H{sub 5},H){sub 2.9}U{sub 1.1}Ce{sub 0.9}(C{sub 2}O{sub 4}){sub 5}·10H{sub 2}O from a conventional X-ray diffraction diagram obtained on a powder synthesized by a fast vortex process

    SciTech Connect (OSTI)

    Brackx, E.; Laval, J.P.; Dugne, O.; Feraud, J.P.; Arab-Chapelet, B.

    2015-01-15

    In the context of research on U/minor actinides for nuclear fuel reprocessing in the transmutation process, developments are first studied with surrogates containing uranium and lanthanides to facilitate testing. The tests consist of precipitating and calcining a hydrazinium uranium/cerium oxalate. The structure of this oxalate had not been previously determined, but was necessary to validate the physicochemical mechanisms involved. The present study, firstly demonstrates the structural similarity of the U/Ce oxalate phase (N{sub 2}H{sub 5},H){sub 2.9}U{sub 1.1}Ce{sub 0.9}(C{sub 2}O{sub 4}){sub 5}·10H{sub 2}O, synthesized using a vortex precipitator for continuous synthesis of actinide oxalates, with previously known oxalates, crystallizing in P6{sub 3}/mmc symmetry, obtained by more classical methods. This fast precipitation process induces massive nucleation of fine powders. Their structural and microstructural determination confirms that the raw and dried phases belong to the same structural family as (NH{sub 4}){sub 2}U{sub 2}(C{sub 2}O{sub 4}){sub 5}·0.7H{sub 2}O whose structure was described by Chapelet-Arab in P6{sub 3}/mmc symmetry, using single crystal data. However, they present an extended disorder inside the tunnels of the structure, even after drying at 100 °C, between water and hydrazinium ions. This disorder is directly related to the fast vortex method. This structure determination can be used as a basis for further semi-quantitative analysis on the U/minor actinides products formed under various experimental conditions. - Highlights: • Uranium cerium oxalate precipitate characterization by X-ray powder diffraction. • Morphology characterization by SEM analysis. • Structure determination by unit cell Rietveld refinement.

  20. A high temperature diffraction-resistance study of chalcopyrite, CuFeS{sub 2}

    SciTech Connect (OSTI)

    Engin, T.E.; Powell, A.V.; Hull, S.

    2011-08-15

    The electrical, magnetic and structural properties of synthetic chalcopyrite, CuFeS{sub 2}, have been studied up to 873 K using DC resistance measurements performed in-situ during neutron powder diffraction experiments. Under ambient conditions the material adopts the accepted structural model for CuFeS{sub 2} in the space group I4-bar 2d, with the magnetic moment of the Fe{sup 3+} cations aligned along [001]. The electrical resistivity is around 0.3 {Omega} cm under ambient conditions, consistent with semiconductor character, and decreases slightly with increase in temperature until a more abrupt fall occurs in the region 750-800 K. This abrupt change in resistivity is accompanied by a structural transition to a cubic zinc blende structured phase (space group F4-bar 3m) in which Cu{sup +} and Fe{sup 3+} cations are disordered over the same tetrahedral crystallographic sites and by a simultaneous loss of long-range magnetic order. The implications of these results are discussed in the context of previous studies of the chalcopyrite system. - Graphical abstract: Structural, magnetic and electrical properties of CuFeS{sub 2} to 873 K have been investigated using DC resistance measurements, performed in-situ during the collection of powder neutron diffraction data. Highlights: > Structural, magnetic and electronic properties are probed simultaneously. > A fall in resistivity at high temperatures is associated with cation disorder. > The order-disorder transition is accompanied by the loss of magnetic order. > The structural and magnetic phase transition is preceded by a 2-phase region. > Sulphur loss at high temperatures causes the phase transitions to be irreversible.

  1. Preparing titanium nitride powder

    DOE Patents [OSTI]

    Bamberger, Carlos E.

    1989-07-04

    A process for making titanium nitride powder by reaction of titanium phosphates with sodium cyanide.

  2. Preparing titanium nitride powder

    DOE Patents [OSTI]

    Bamberger, Carlos E.

    1989-01-01

    A process for making titanium nitride powder by reaction of titanium phosphates with sodium cyanide.

  3. Preparation of titanium diboride powder

    DOE Patents [OSTI]

    Brynestad, Jorulf; Bamberger, Carlos E.

    1985-01-01

    Finely-divided titanium diboride or zirconium diboride powders are formed by reacting gaseous boron trichloride with a material selected from the group consisting of titanium powder, zirconium powder, titanium dichloride powder, titanium trichloride powder, and gaseous titanium trichloride.

  4. Preparation of metal diboride powders

    DOE Patents [OSTI]

    Brynestad, J.; Bamberger, C.E.

    Finely-divided titanium diboride or zirconium diboride powders are formed by reacting gaseous boron trichloride with a material selected from the group of consisting of titanium powder, zirconium powder, titanium dichloride powder, titanium trichloride powder, and gaseous titanium trichloride.

  5. Neutronic reactor

    DOE Patents [OSTI]

    Wende, Charles W. J.; Babcock, Dale F.; Menegus, Robert L.

    1983-01-01

    A nuclear reactor includes an active portion with fissionable fuel and neutron moderating material surrounded by neutron reflecting material. A control element in the active portion includes a group of movable rods constructed of neutron-absorbing material. Each rod is movable with respect to the other rods to vary the absorption of neutrons and effect control over neutron flux.

  6. Precision powder feeder

    DOE Patents [OSTI]

    Schlienger, M. Eric; Schmale, David T.; Oliver, Michael S.

    2001-07-10

    A new class of precision powder feeders is disclosed. These feeders provide a precision flow of a wide range of powdered materials, while remaining robust against jamming or damage. These feeders can be precisely controlled by feedback mechanisms.

  7. Three-dimensional boron particle loaded thermal neutron detector

    DOE Patents [OSTI]

    Nikolic, Rebecca J.; Conway, Adam M.; Graff, Robert T.; Kuntz, Joshua D.; Reinhardt, Catherine; Voss, Lars F.; Cheung, Chin Li; Heineck, Daniel

    2014-09-09

    Three-dimensional boron particle loaded thermal neutron detectors utilize neutron sensitive conversion materials in the form of nano-powders and micro-sized particles, as opposed to thin films, suspensions, paraffin, etc. More specifically, methods to infiltrate, intersperse and embed the neutron nano-powders to form two-dimensional and/or three-dimensional charge sensitive platforms are specified. The use of nano-powders enables conformal contact with the entire charge-collecting structure regardless of its shape or configuration.

  8. Multiple feed powder splitter

    DOE Patents [OSTI]

    Lewis, Gary K. (Los Alamos, NM); Less, Richard M. (Los Alamos, NM)

    2001-01-01

    A device for providing uniform powder flow to the nozzles when creating solid structures using a solid fabrication system such as the directed light fabrication (DLF) process. In the DLF process, gas entrained powders are passed through the focal point of a moving high-power laser light which fuses the particles in the powder to a surface being built up in layers. The invention is a device providing uniform flow of gas entrained powders to the nozzles of the DLF system. The device comprises a series of modular splitters which are slidably interconnected and contain an integral flow control mechanism. The device can take the gas entrained powder from between one to four hoppers and split the flow into eight tubular lines which feed the powder delivery nozzles of the DLF system.

  9. Multiple feed powder splitter

    DOE Patents [OSTI]

    Lewis, Gary K. (Los Alamos, NM); Less, Richard M. (Los Alamos, NM)

    2002-01-01

    A device for providing uniform powder flow to the nozzles when creating solid structures using a solid fabrication system such as the directed light fabrication (DLF) process. In the DLF process, gas entrained powders are passed through the focal point of a moving high-power laser light which fuses the particles in the powder to a surface being built up in layers. The invention is a device providing uniform flow of gas entrained powders to the nozzles of the DLF system. The device comprises a series of modular splitters which are slidably interconnected and contain an integral flow control mechanism. The device can take the gas entrained powder from between one to four hoppers and split the flow into eight tubular lines which feed the powder delivery nozzles of the DLF system.

  10. Neutron skins and neutron stars

    SciTech Connect (OSTI)

    Piekarewicz, J.

    2013-11-07

    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.

  11. Biaxially textured articles formed by powder metallurgy

    DOE Patents [OSTI]

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-05

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of ternary mixtures consisting of: Ni powder, Cu powder, and Al powder, Ni powder, Cr powder, and Al powder; Ni powder, W powder and Al powder; Ni powder, V powder, and Al powder; Ni powder, Mo powder, and Al powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  12. Neutron guide

    DOE Patents [OSTI]

    Greene, Geoffrey L.

    1999-01-01

    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.

  13. Neutron dosimetry

    DOE Patents [OSTI]

    Quinby, Thomas C.

    1976-07-27

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

  14. Design and implementation of a multiaxial loading capability during heating on an engineering neutron diffractometer

    DOE PAGES-Beta [OSTI]

    Benafan, O.; Padula, S. A.; Skorpenske, H. D.; An, K.; Vaidyanathan, R.

    2014-10-02

    Here we discuss a gripping capability that was designed, implemented, and tested for in situ neutron diffraction measurements during multiaxial loading and heating on the VULCAN engineering materials diffractometer at the spallation neutron source at Oak Ridge National Laboratory.

  15. Defectiveness of the crystal structure of electroerosion powders

    SciTech Connect (OSTI)

    Fominskii, L.P.; Myuller, A.S.; Levchuk, M.V.

    1988-03-01

    The fine structure and defectiveness of metal powder crystal lattices produced by electroerosion dispersion were examined. Dispersion was performed on granulated aluminum, Armco iron, carbon steels, and tungsten. The fine structure was examined by x-ray diffraction. Harmonic analysis was performed using a computer and a program which calculates not only the expansion coefficients of the functions into a Fourier series but also the microdistortions and the dimensions of the mosaic blocks. Electroerosion powders were found to have higher density of crystal lattice defects which can increase their chemical and catalytic activity, improve the metallic electroerosion powder passivation, and increase their corrosion resistance.

  16. The Macromolecular Neutron Diffractometer MaNDi at the Spallation Neutron Source

    DOE PAGES-Beta [OSTI]

    Coates, Leighton; Cuneo, Matthew J.; Frost, Matthew J.; He, Junhong; Weiss, Kevin L.; McFeeters, Hana; Tomanicek, Stephen J.; Vandavasi, Venu Gopal; Langan, Paul; Iverson, Erik B.

    2015-07-18

    The Macromolecular Neutron Diffractometer (MaNDi) is located on beamline 11B of the Spallation Neutron Source at Oak Ridge National Laboratory. Moreover, the instrument is a neutron time-of-flight wavelength-resolved Laue diffractometer optimized to collect diffraction data from single crystals. Finally, the instrument has been designed to provide flexibility in several instrumental parameters, such as beam divergence and wavelength bandwidth, to allow data collection from a range of macromolecular systems.

  17. The Macromolecular Neutron Diffractometer MaNDi at the Spallation Neutron Source

    SciTech Connect (OSTI)

    Coates, Leighton; Cuneo, Matthew J.; Frost, Matthew J.; He, Junhong; Weiss, Kevin L.; McFeeters, Hana; Tomanicek, Stephen J.; Vandavasi, Venu Gopal; Langan, Paul; Iverson, Erik B.

    2015-07-18

    The Macromolecular Neutron Diffractometer (MaNDi) is located on beamline 11B of the Spallation Neutron Source at Oak Ridge National Laboratory. Moreover, the instrument is a neutron time-of-flight wavelength-resolved Laue diffractometer optimized to collect diffraction data from single crystals. Finally, the instrument has been designed to provide flexibility in several instrumental parameters, such as beam divergence and wavelength bandwidth, to allow data collection from a range of macromolecular systems.

  18. Multilayer dielectric diffraction gratings

    DOE Patents [OSTI]

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

    1999-05-25

    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.

  19. Multilayer dielectric diffraction gratings

    DOE Patents [OSTI]

    Perry, Michael D.; Britten, Jerald A.; Nguyen, Hoang T.; Boyd, Robert; Shore, Bruce W.

    1999-01-01

    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.

  20. SAXS-Diffraction_Workshop

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    Workshop on Small-angle X-ray ScatteringDiffraction in Biology October 21, 1998 SPEAKERS Dimitri Svergun, EMBL-Hamburg John E. Johnson, The Scripps Research Institute Wah Chiu, ...

  1. Diffraction with CMS

    SciTech Connect (OSTI)

    Pereira, Antonio Vilela

    2011-07-15

    The observation of diffraction at LHC with the CMS detector at {radical}(s) = 900 and 2360 GeV is presented, along with a comparison of the data with the predictions of the PYTHIA and PHOJET generators.

  2. Phase Concentration Determination of Fe16N2 Using State of the Art Neutron Scattering Techniques

    DOE PAGES-Beta [OSTI]

    Bennett, S. P.; Feygenson, M.; Jiang, Y.; Zande, B. J.; Zhang, X.; Sankar, S. G.; Wang, J. P.; Lauter, V.

    2016-03-25

    Limitation on the availability of rare earth elements have made it imperative that new high energy product rare earth free permanent magnet materials are developed for the next generation of energy systems. One promising low cost permanent magnet candidate for a high energy magnet is -Fe16N2, whose giant magnetic moment has been predicted to be well above any other from conventional first principles calculations. Despite its great promise, the phase is metastable; making synthesis of the pure phase difficult, resulting in less than ideal magnetic characteristics. This instability gives way to a slew of possible secondary phases (i.e. -Fe, Fe2O3,more » Fe8N, Fe4N ) whose concentrations are difficult to detect by conventional x-ray diffraction. Moreover, we show how high resolution neutron diffraction and polarized neutron reflectometry can be used to extract the phase concentration ratio of the giant magnetic phase from ultra-small powder sample sizes (~0.1g) and thin films. These studies have led to the discovery of promising fabrication methods for both homogeneous thin films, and nanopowders containing the highest reported to date (>95%) phase concentrations of room temperature stable -Fe16N2.« less

  3. Reflective diffraction grating

    DOE Patents [OSTI]

    Lamartine, Bruce C.

    2003-06-24

    Reflective diffraction grating. A focused ion beam (FIB) micromilling apparatus is used to store color images in a durable medium by milling away portions of the surface of the medium to produce a reflective diffraction grating with blazed pits. The images are retrieved by exposing the surface of the grating to polychromatic light from a particular incident bearing and observing the light reflected by the surface from specified reception bearing.

  4. Backscattered Diffraction | Materials Science | NREL

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    Backscattered Diffraction Backscattered diffraction images showing crystalline orientation (left) and grain distribution (right). EBSD images showing properties of crystalline semiconductor materials at high resolution (micrometers). We have found electron backscattered diffraction (EBSD) to be a valuable tool for assessing crystalline specimens. EBSD is becoming an established, fully automated mode that indexes electron diffraction patterns produced by backscattered electrons under diffraction

  5. Neutron diffractometer for bio-crystallography (BIX) with an imaging plate neutron detector

    SciTech Connect (OSTI)

    Niimura, Nobuo

    1994-12-31

    We have constructed a dedicated diffractometer for neutron crystallography in biology (BIX) on the JRR-3M reactor at JAERI (Japan Atomic Energy Research Institute). The diffraction intensity from a protein crystal is weaker than that from most inorganic materials. In order to overcome the intensity problem, an elastically bent silicon monochromator and a large area detector system were specially designed. A preliminary result of diffraction experiment using BIX has been reported. An imaging plate neutron detector has been developed and a feasibility experiment was carried out on BIX. Results are reported. An imaging plate neutron detector has been developed and a feasibility test was carried out using BIX.

  6. Neutron detector

    DOE Patents [OSTI]

    Stephan, Andrew C.; Jardret; Vincent D.

    2011-04-05

    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.

  7. Correlating sampling and intensity statistics in nanoparticle diffraction experiments

    DOE PAGES-Beta [OSTI]

    Öztürk, Hande; Yan, Hanfei; Hill, John P.; Noyan, I. Cevdet

    2015-07-28

    It is shown in a previous article [Öztürk, Yan, Hill & Noyan (2014).J. Appl. Cryst.47, 1016–1025] that the sampling statistics of diffracting particle populations within a polycrystalline ensemble depended on the size of the constituent crystallites: broad X-ray peak breadths enabled some nano-sized particles to contribute more than one diffraction spot to Debye–Scherrer rings. Here it is shown that the equations proposed by Alexander, Klug & Kummer [J. Appl. Phys.(1948),19, 742–753] (AKK) to link diffracting particle and diffracted intensity statistics are not applicable if the constituent crystallites of the powder are below 10 nm. In this size range, (i) themore » one-to-one correspondence between diffracting particles and Laue spots assumed in the AKK analysis is not satisfied, and (ii) the crystallographic correlation between Laue spots originating from the same grain invalidates the assumption that all diffracting plane normals are randomly oriented and uncorrelated. Such correlation produces unexpected results in the selection of diffracting grains. For example, three or more Laue spots from a given grain for a particular reflection can only be observed at certain wavelengths. In addition, correcting the diffracted intensity values by the traditional Lorentz term, 1/cos θ, to compensate for the variation of particles sampled within a reflection band does not maintain fidelity to the number of poles contributing to the diffracted signal. A new term, cos θB/cos θ, corrects this problem.« less

  8. Pyrotechnic filled molding powder

    DOE Patents [OSTI]

    Hartzel, Lawrence W.; Kettling, George E.

    1978-01-01

    The disclosure relates to thermosetting molding compounds and more particularly to a pyrotechnic filled thermosetting compound comprising a blend of unfilled diallyl phthalate molding powder and a pyrotechnic mixture.

  9. Ultracold neutrons

    SciTech Connect (OSTI)

    Saunders, Alexander

    2015-06-22

    This series of slides describes ultracold neutrons (UCN) and their properties, various UCN sources, and an overview of UCN-based experiments. Numerous diagrams and photographs are included.

  10. Biaxially textured articles formed by powder metallurgy

    DOE Patents [OSTI]

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2004-09-14

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  11. Biaxially textured articles formed by powder metallurgy

    DOE Patents [OSTI]

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-07-29

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  12. Biaxially textured articles formed by powder metallurgy

    DOE Patents [OSTI]

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-19

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  13. Biaxially textured articles formed by powder metallurgy

    DOE Patents [OSTI]

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-26

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  14. Biaxially textured articles formed by powder metallurgy

    DOE Patents [OSTI]

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2005-01-25

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  15. Biaxially textured articles formed by powder metallurgy

    DOE Patents [OSTI]

    Goval, Amit; Williams, Robert K.; Kroeger, Donald M.

    2005-06-07

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  16. Biaxially textured articles formed by powder metallurgy

    DOE Patents [OSTI]

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2005-05-10

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  17. Biaxially textured articles formed by powder metallurgy

    DOE Patents [OSTI]

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2004-09-28

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  18. NEUTRONIC REACTOR

    DOE Patents [OSTI]

    Fermi, E.; Zinn, W.H.; Anderson, H.L.

    1958-09-16

    Means are presenied for increasing the reproduction ratio of a gaphite- moderated neutronic reactor by diminishing the neutron loss due to absorption or capture by gaseous impurities within the reactor. This means comprised of a fluid-tight casing or envelope completely enclosing the reactor and provided with a valve through which the casing, and thereby the reactor, may be evacuated of atmospheric air.

  19. Neutronic reactor

    DOE Patents [OSTI]

    Wende, Charles W. J.

    1976-08-17

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

  20. Neutron tubes

    DOE Patents [OSTI]

    Leung, Ka-Ngo; Lou, Tak Pui; Reijonen, Jani

    2008-03-11

    A neutron tube or generator is based on a RF driven plasma ion source having a quartz or other chamber surrounded by an external RF antenna. A deuterium or mixed deuterium/tritium (or even just a tritium) plasma is generated in the chamber and D or D/T (or T) ions are extracted from the plasma. A neutron generating target is positioned so that the ion beam is incident thereon and loads the target. Incident ions cause D-D or D-T (or T-T) reactions which generate neutrons. Various embodiments differ primarily in size of the chamber and position and shape of the neutron generating target. Some neutron generators are small enough for implantation in the body. The target may be at the end of a catheter-like drift tube. The target may have a tapered or conical surface to increase target surface area.

  1. Neutron source

    DOE Patents [OSTI]

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

    1975-10-21

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

  2. Ultrafine hydrogen storage powders

    DOE Patents [OSTI]

    Anderson, Iver E.; Ellis, Timothy W.; Pecharsky, Vitalij K.; Ting, Jason; Terpstra, Robert; Bowman, Robert C.; Witham, Charles K.; Fultz, Brent T.; Bugga, Ratnakumar V.

    2000-06-13

    A method of making hydrogen storage powder resistant to fracture in service involves forming a melt having the appropriate composition for the hydrogen storage material, such, for example, LaNi.sub.5 and other AB.sub.5 type materials and AB.sub.5+x materials, where x is from about -2.5 to about +2.5, including x=0, and the melt is gas atomized under conditions of melt temperature and atomizing gas pressure to form generally spherical powder particles. The hydrogen storage powder exhibits improved chemcial homogeneity as a result of rapid solidfication from the melt and small particle size that is more resistant to microcracking during hydrogen absorption/desorption cycling. A hydrogen storage component, such as an electrode for a battery or electrochemical fuel cell, made from the gas atomized hydrogen storage material is resistant to hydrogen degradation upon hydrogen absorption/desorption that occurs for example, during charging/discharging of a battery. Such hydrogen storage components can be made by consolidating and optionally sintering the gas atomized hydrogen storage powder or alternately by shaping the gas atomized powder and a suitable binder to a desired configuration in a mold or die.

  3. Iowa Powder Atomization Technologies

    ScienceCinema (OSTI)

    None

    2013-03-01

    The same atomization effect seen in a fuel injector is being applied to titanium metal resulting in fine titanium powders that are less than half the width of a human hair. Titanium melts above 3,000°F and is highly corrosive therefore requiring specialized containers. The liquid titanium is poured through an Ames Laboratory - USDOE patented tube which is intended to increase the energy efficiency of the atomization process, which has the ability to dramatically decrease the cost of fine titanium powders. This novel process could open markets for green manufacturing of titanium components from jet engines to biomedical implants.

  4. Iowa Powder Atomization Technologies

    SciTech Connect (OSTI)

    2012-01-01

    The same atomization effect seen in a fuel injector is being applied to titanium metal resulting in fine titanium powders that are less than half the width of a human hair. Titanium melts above 3,000°F and is highly corrosive therefore requiring specialized containers. The liquid titanium is poured through an Ames Laboratory - USDOE patented tube which is intended to increase the energy efficiency of the atomization process, which has the ability to dramatically decrease the cost of fine titanium powders. This novel process could open markets for green manufacturing of titanium components from jet engines to biomedical implants.

  5. Thermal neutron detection system

    DOE Patents [OSTI]

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

    2000-01-01

    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.

  6. The application of inelastic neutron scattering to explore the significance of a magnetic transition in an iron based Fischer-Tropsch catalyst that is active for the hydrogenation of CO

    SciTech Connect (OSTI)

    Warringham, Robbie; McFarlane, Andrew R.; Lennon, David; MacLaren, Donald A.; Webb, Paul B.; Tooze, Robert P.; Taylor, Jon; Ewings, Russell A.; Parker, Stewart F.

    2015-11-07

    An iron based Fischer-Tropsch synthesis catalyst is evaluated using CO hydrogenation at ambient pressure as a test reaction and is characterised by a combination of inelastic neutron scattering (INS), powder X-ray diffraction, temperature-programmed oxidation, Raman scattering, and transmission electron microscopy. The INS spectrum of the as-prepared bulk iron oxide pre-catalyst (hematite, α-Fe{sub 2}O{sub 3}) is distinguished by a relatively intense band at 810 cm{sup −1}, which has previously been tentatively assigned as a magnon (spinon) feature. An analysis of the neutron scattering intensity of this band as a function of momentum transfer unambiguously confirms this assignment. Post-reaction, the spinon feature disappears and the INS spectrum is characterised by the presence of a hydrocarbonaceous overlayer. A role for the application of INS in magnetic characterisation of iron based FTS catalysts is briefly considered.

  7. Cryogenic Neutron Protein Crystallography: routine methods and potential benefits

    SciTech Connect (OSTI)

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

    2014-01-01

    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.

  8. NEUTRONIC REACTORS

    DOE Patents [OSTI]

    Wigner, E.P.

    1960-11-22

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

  9. NEUTRONIC REACTOR

    DOE Patents [OSTI]

    Wade, E.J.

    1958-09-16

    This patent relates to a reflector means for a neutronic reactor. A reflector comprised of a plurality of vertically movable beryllium control members is provided surrounding the sides of the reactor core. An absorber of fast neutrons comprised of natural uramum surrounds the reflector. An absorber of slow neutrons surrounds the absorber of fast neutrons and is formed of a plurality of beryllium blocks having natural uranium members distributcd therethrough. in addition, a movable body is positioned directly below the core and is comprised of a beryllium reflector and an absorbing member attached to the botiom thereof, the absorbing member containing a substance selected from the goup consisting of natural urantum and Th/sup 232/.

  10. Neutron range spectrometer

    DOE Patents [OSTI]

    Manglos, S.H.

    1988-03-10

    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.

  11. NEUTRONIC REACTOR

    DOE Patents [OSTI]

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

    1961-11-21

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

  12. NEUTRON SOURCES

    DOE Patents [OSTI]

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

    1963-01-15

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

  13. Method for synthesizing powder materials

    DOE Patents [OSTI]

    Buss, R.J.; Ho, P.

    1988-01-21

    A method for synthesizing ultrafine powder materials, for example, ceramic and metal powders, comprises admitting gaseous reactants from which the powder material is to be formed into a vacuum reaction chamber maintained at a pressure less than atmospheric and at a temperature less than about 400/degree/K (127/degree/C). The gaseous reactants are directed through a glow discharge provided in the vacuum reaction chamber to form the ultrafine powder material. 1 fig.

  14. Method to blend separator powders

    SciTech Connect (OSTI)

    Guidotti, Ronald A.; Andazola, Arthur H.; Reinhardt, Frederick W.

    2007-12-04

    A method for making a blended powder mixture, whereby two or more powders are mixed in a container with a liquid selected from nitrogen or short-chain alcohols, where at least one of the powders has an angle of repose greater than approximately 50 degrees. The method is useful in preparing blended powders of Li halides and MgO for use in the preparation of thermal battery separators.

  15. Search for neutrons from deuterated palladium subject to high electrical currents

    SciTech Connect (OSTI)

    Taylor, S.F. |; Claytor, T.N.; Tuggle, D.G.; Jones, S.E.

    1994-04-01

    Tritium has been detected evolving from samples of deuteriated palladium wires and powders subject to pulsed high voltage at Los Alamos. They wanted to measure whether these samples were emitting neutrons. The idea of pulsing current through the wires and powders was to drive the deuterium in and out by rapid electrical heating. With promising tritium results in hand, the experiments were prepared at Los Alamos, and then taken to BYU and run in the neutron detector located in a tunnel in Provo canyon under 35 m of rock and dirt overburden. The neutrons detector and sample setup are described. Results including total neutron counts, time distributions, and an indication of the energy distributions are discussed. The results do not provide compelling evidence of neutron production, but are not inconsistent with earlier measurements of neutrons and tritium. Difficulties in explaining the difference in tritium and neutron measurements are also discussed. Plans for further work are presented.

  16. Neutron diffraction study and anomalous negative thermal expansion...

    Office of Scientific and Technical Information (OSTI)

    does not result in the emergence of superconductivity or any other new ground state. ... results suggest that the absence of superconductivity in these materials could be related ...

  17. The early development of neutron diffraction: Science in the...

    Office of Scientific and Technical Information (OSTI)

    Authors: Mason, Thom 1 ; Gawne, Timothy J 1 ; Nagler, Stephen E 1 ; Nestor, Margaret Boone 2 ; Carpenter, John M 1 + Show Author Affiliations ORNL ORNL Bonnie ORNL ...

  18. Characterization of welding residual stresses with neutron diffraction

    SciTech Connect (OSTI)

    Wang, X.L.; Spooner, S.; Hubbard, C.R.; Taljat, B.; Feng, Z.

    1998-03-01

    Welding residual stresses are a key concern in the fabrication and use of structural components containing welds. Residual stresses in welds are caused by non-uniform expansion and shrinkage of differently heated zones during the thermal transient of a weld pass. In some alloys, solid state phase transformations occurring during the welding transient contribute additional residual stresses. Manufacturing problems arising from welding residual stresses include cracking and dimensional distortion. During use, tensile stresses in the welded zone limit the fatigue resistance of the component under cyclic loading. In an aggressive environment, tensile welding residual stresses also create a necessary condition for stress-corrosion cracking to take place.

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

    Energy.gov (indexed) [DOE]

    Materials Characterization Capabilities at the High Temperature Materials Laboratory and HTML User Program Success Stories Characterization of Materials for Li-ion Batteries: ...

  20. Conversion method of powder inelastic scattering data for one-dimensional systems

    SciTech Connect (OSTI)

    Tomiyasu, Dr. Keisuke; Fujita, Prof. Masaki; Kolesnikov, Alexander I; Bewley, Robert I.; Bull, Dr. Martyn J.; Bennington, Dr. Stephen M.

    2009-01-01

    Extracting dispersive magnetic excitations from inelastic neutron scattering data usually requires large single crystals. We present a simple yet powerful method for extracting such information from polycrystalline or powder data for one-dimensional systems. We demonstrate the effectiveness of this data treatment by extracting dispersion curves from powder inelastic neutron scattering data on the one-dimensional spin-half systems: CuGeO3 and Rb2Cu2Mo3O12. For many such materials it is not possible to grow sufficiently large crystals and this method offers a quick and efficient way to study their magnetic excitations.

  1. NEUTRONIC REACTOR

    DOE Patents [OSTI]

    Hurwitz, H. Jr.; Brooks, H.; Mannal, C.; Payne, J.H.; Luebke, E.A.

    1959-03-24

    A reactor of the heterogeneous, liquid cooled type is described. This reactor is comprised of a central region of a plurality of vertically disposed elongated tubes surrounded by a region of moderator material. The central region is comprised of a central core surrounded by a reflector region which is surrounded by a fast neutron absorber region, which in turn is surrounded by a slow neutron absorber region. Liquid sodium is used as the primary coolant and circulates through the core which contains the fuel elements. Control of the reactor is accomplished by varying the ability of the reflector region to reflect neutrons back into the core of the reactor. For this purpose the reflector is comprised of moderator and control elements having varying effects on reactivity, the control elements being arranged and actuated by groups to give regulation, shim, and safety control.

  2. Preparation of superconductor precursor powders

    DOE Patents [OSTI]

    Bhattacharya, Raghunath

    1998-01-01

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic and/or reduced particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of all metals in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products.

  3. NEUTRONIC REACTOR

    DOE Patents [OSTI]

    Fermi, E.; Szilard, L.

    1957-09-24

    Reactors of the type employing plates of natural uranium in a moderator are discussed wherein the plates are um-formly disposed in parallel relationship to each other thereby separating the moderator material into distinct and individual layers. Each plate has an uninterrupted sunface area substantially equal to the cross-sectional area of the active portion of the reactor, the particular size of the plates and the volume ratio of moderator to uranium required to sustain a chain reaction being determinable from the known purity of these materials and other characteristics such as the predictable neutron losses due to the formation of radioactive elements of extremely high neutron capture cross section.

  4. NEUTRONIC REACTOR

    DOE Patents [OSTI]

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

    1958-04-15

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

  5. Silicon nitride/silicon carbide composite powders

    DOE Patents [OSTI]

    Dunmead, Stephen D.; Weimer, Alan W.; Carroll, Daniel F.; Eisman, Glenn A.; Cochran, Gene A.; Susnitzky, David W.; Beaman, Donald R.; Nilsen, Kevin J.

    1996-06-11

    Prepare silicon nitride-silicon carbide composite powders by carbothermal reduction of crystalline silica powder, carbon powder and, optionally, crystalline silicon nitride powder. The crystalline silicon carbide portion of the composite powders has a mean number diameter less than about 700 nanometers and contains nitrogen. The composite powders may be used to prepare sintered ceramic bodies and self-reinforced silicon nitride ceramic bodies.

  6. Correlating sampling and intensity statistics in nanoparticle diffraction experiments

    SciTech Connect (OSTI)

    Öztürk, Hande; Yan, Hanfei; Hill, John P.; Noyan, I. Cevdet

    2015-07-28

    It is shown in a previous article [Öztürk, Yan, Hill & Noyan (2014).J. Appl. Cryst.47, 1016–1025] that the sampling statistics of diffracting particle populations within a polycrystalline ensemble depended on the size of the constituent crystallites: broad X-ray peak breadths enabled some nano-sized particles to contribute more than one diffraction spot to Debye–Scherrer rings. Here it is shown that the equations proposed by Alexander, Klug & Kummer [J. Appl. Phys.(1948),19, 742–753] (AKK) to link diffracting particle and diffracted intensity statistics are not applicable if the constituent crystallites of the powder are below 10 nm. In this size range, (i) the one-to-one correspondence between diffracting particles and Laue spots assumed in the AKK analysis is not satisfied, and (ii) the crystallographic correlation between Laue spots originating from the same grain invalidates the assumption that all diffracting plane normals are randomly oriented and uncorrelated. Such correlation produces unexpected results in the selection of diffracting grains. For example, three or more Laue spots from a given grain for a particular reflection can only be observed at certain wavelengths. In addition, correcting the diffracted intensity values by the traditional Lorentz term, 1/cos θ, to compensate for the variation of particles sampled within a reflection band does not maintain fidelity to the number of poles contributing to the diffracted signal. A new term, cos θB/cos θ, corrects this problem.

  7. Neutron irradiation induced amorphization of silicon carbide

    SciTech Connect (OSTI)

    Snead, L.L.; Hay, J.C.

    1998-09-01

    This paper provides the first known observation of silicon carbide fully amorphized under neutron irradiation. Both high purity single crystal hcp and high purity, highly faulted (cubic) chemically vapor deposited (CVD) SiC were irradiated at approximately 60 C to a total fast neutron fluence of 2.6 {times} 10{sup 25} n/m{sup 2}. Amorphization was seen in both materials, as evidenced by TEM, electron diffraction, and x-ray diffraction techniques. Physical properties for the amorphized single crystal material are reported including large changes in density ({minus}10.8%), elastic modulus as measured using a nanoindentation technique ({minus}45%), hardness as measured by nanoindentation ({minus}45%), and standard Vickers hardness ({minus}24%). Similar property changes are observed for the critical temperature for amorphization at this neutron dose and flux, above which amorphization is not possible, is estimated to be greater than 130 C.

  8. High-Energy X-Ray Diffraction Analysis Tool

    Energy Science and Technology Software Center (OSTI)

    2011-11-29

    The functionality of heRXD includes the following: distance and angular calibration and viewing flat-panel detector images used for X-ray diffraction; image (polar) rebinning or "caking"; line position fitting in powder diffraction images; image segmentation or "blob finding"; crystal orentation indesing; and lattice vector refinement. These functionalities encompass a critical set analyzing teh data for high-energy diffraction measurements that are currently performed at synchrotron sources such as the Advanced Photon Source (APS). The software design modularmore » and open source under LGPL. The intent is to provide a common framework and graphical user interface that has the ability to utillize internal as well as external subroutines to provide various optins for performing the fuctionalities listed above. The software will initially be deployed at several national user facilities--including APS, ALS, and CHESS--and then made available for download using a hosting service such as sourceforge.« less

  9. Multilayer diffraction grating

    DOE Patents [OSTI]

    Barbee, Jr., Troy W.

    1990-01-01

    This invention is for a reflection diffraction grating that functions at X-ray to VUV wavelengths and at normal angles of incidence. The novel grating is comprised of a laminar grating of period D with flat-topped grating bars. A multiplicity of layered synthetic microstructures, of period d and comprised of alternating flat layers of two different materials, are disposed on the tops of the grating bars of the laminar grating. In another embodiment of the grating, a second multiplicity of layered synthetic microstructures are also disposed on the flat faces, of the base of the grating, between the bars. D is in the approximate range from 3,000 to 50,000 Angstroms, but d is in the approximate range from 10 to 400 Angstroms. The laminar grating and the layered microstructures cooperatively interact to provide many novel and beneficial instrumentational advantages.

  10. Multilayer diffraction grating

    DOE Patents [OSTI]

    Barbee, T.W. Jr.

    1990-04-10

    This invention is for a reflection diffraction grating that functions at X-ray to VUV wavelengths and at normal angles of incidence. The novel grating is comprised of a laminar grating of period D with flat-topped grating bars. A multiplicity of layered synthetic microstructures, of period d and comprised of alternating flat layers of two different materials, are disposed on the tops of the grating bars of the laminar grating. In another embodiment of the grating, a second multiplicity of layered synthetic microstructures are also disposed on the flat faces, of the base of the grating, between the bars. D is in the approximate range from 3,000 to 50,000 Angstroms, but d is in the approximate range from 10 to 400 Angstroms. The laminar grating and the layered microstructures cooperatively interact to provide many novel and beneficial instrumentational advantages. 2 figs.

  11. Phase shifting diffraction interferometer

    DOE Patents [OSTI]

    Sommargren, Gary E.

    1996-01-01

    An interferometer which has the capability of measuring optical elements and systems with an accuracy of .lambda./1000 where .lambda. is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about .lambda./50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms.

  12. Phase shifting diffraction interferometer

    DOE Patents [OSTI]

    Sommargren, G.E.

    1996-08-29

    An interferometer which has the capability of measuring optical elements and systems with an accuracy of {lambda}/1000 where {lambda} is the wavelength of visible light. Whereas current interferometers employ a reference surface, which inherently limits the accuracy of the measurement to about {lambda}/50, this interferometer uses an essentially perfect spherical reference wavefront generated by the fundamental process of diffraction. This interferometer is adjustable to give unity fringe visibility, which maximizes the signal-to-noise, and has the means to introduce a controlled prescribed relative phase shift between the reference wavefront and the wavefront from the optics under test, which permits analysis of the interference fringe pattern using standard phase extraction algorithms. 8 figs.

  13. A simple procedure to prepare spherical {alpha}-alumina powders

    SciTech Connect (OSTI)

    Liu Hongyu [State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012 (China); Ning Guiling [State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012 (China)], E-mail: ninggl@dlut.edu.cn; Gan Zhihong; Lin Yuan [State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012 (China)

    2009-04-02

    Spherical {alpha}-alumina powders were prepared by the controlled hydrolysis of aluminum isopropoxide in a hydrolysis system consisting of octanol and acetonitrile. Diverse solvents to dissolve reactant formed diverse hydrolysis systems and affected particle shape of {alpha}-alumina powders. The precursors crystallized to {gamma}-alumina at 1000 deg. C and converted to {alpha}-alumina at 1150 deg. C without intermediate phases. The particle morphology of precursor was retained after it crystallized to {alpha}-alumina. The heating rate influenced the particle shape and the state of agglomeration during calcination process. The thermal properties of the precursors were characterized by thermal gravimetric and differential thermal analysis. X-ray diffraction technique was used to confirm the conversion of crystalline phase of alumina powders from amorphous to {alpha}-phase. Transmission electron microscopy was used to investigate the morphologies and size of the precursors and products.

  14. NEUTRONIC REACTORS

    DOE Patents [OSTI]

    Anderson, H.L.

    1958-10-01

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

  15. Neutronic reactor

    DOE Patents [OSTI]

    Carleton, John T.

    1977-01-25

    A graphite-moderated nuclear reactor includes channels between blocks of graphite and also includes spacer blocks between adjacent channeled blocks with an axis of extension normal to that of the axis of elongation of the channeled blocks to minimize changes in the physical properties of the graphite as a result of prolonged neutron bombardment.

  16. A crystallographer keen on showing off the revealing properties of neutrons

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    Revealing properties of neutrons A crystallographer keen on showing off the revealing properties of neutrons Olivier Gourdon shows visiting researchers some of the latest tricks that can be performed using this 100-year old multidisciplinary science. February 27, 2014 Olivier Gourdon Olivier Gourdon "With neutron diffraction, we can learn much more than where are the atoms." At Los Alamos's Lujan Neutron Scattering Center, crystallographer Olivier Gourdon shows visiting researchers

  17. Methods for absorbing neutrons

    DOE Patents [OSTI]

    Guillen, Donna P.; Longhurst, Glen R.; Porter, Douglas L.; Parry, James R.

    2012-07-24

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

  18. Finite Element Scalar Diffraction Theory Code

    Energy Science and Technology Software Center (OSTI)

    1993-08-18

    This computer code calculates the optical diffraction field for diffraction through two-dimensional apertures to aid optical system design. The code allows plotting of the diffraction field.

  19. Neutron diffraction investigation of the evolution of the crystal structure of oxygen-conducting solid solutions (Yb{sub 1-x}Ca{sub x}){sub 2}Ti{sub 2}O{sub 7} (x = 0, 0.05, 0.10)

    SciTech Connect (OSTI)

    Shlyakhtina, A. V.; Sokolov, A. E.; Ul'yanov, V. A.; Trunov, V. A.; Boguslavskii, M. V.; Levchenko, A. V.; Shcherbakova, L. G.

    2009-01-15

    The crystal structure of pyrochlore-like solid solutions (Yb{sub 1-x}Ca{sub x}){sub 2}Ti{sub 2}O{sub 7} (x = 0, 0.05, 0.10) synthesized by high-temperature annealing of mechanically activated initial oxides at temperatures of 1300-1500 deg. C is studied using neutron diffraction. It is found that the Ca{sup 2+} cations are located in the ytterbium sublattice, which apparently favors the splitting of one of the oxygen sublattices [O(2) (48f)] of the pyrochlore structure: the decrease in the occupancy of this sublattice is accompanied by the formation of a new sublattice O(3) (8b), whereas the other oxygen sublattice O(1) (8a) remains unchanged. This rearrangement of the anions in the oxygen subsystem due to the incorporation of an alkaline-earth cation explains the high ionic conductance ({approx}0.2 S/cm at 1000 deg. C) for (Yb{sub 0.9}Ca{sub 0.1}){sub 2}Ti{sub 2}O{sub 7} {approx} 0.2, which is the maximum value observed to date for pyrochlores of the A{sub 2}B{sub 2}O{sub 7} type, where A = Ln and B is a Subgroup IVA element of the periodic system. The bulk and grain-boundary components of the conductivity of (Yb{sub 0.95}Ca{sub 0.05}){sub 2}Ti{sub 2}O{sub 7} synthesized at temperatures of 1300, 1400, and 1500 deg. C are studied using impedance spectroscopy. It is found that the (Yb{sub 0.95}Ca{sub 0.05}){sub 2}Ti{sub 2}O{sub 7} sample synthesized at 1500 deg. C has the highest total conductivity due to the increased grain-boundary component. The bulk component of the ionic conductivity of (Yb{sub 0.95}Ca{sub 0.05}){sub 2}Ti{sub 2}O{sub 7} is hardly affected by the synthesis temperature and depends mainly on the degree of heterovalent substitution.

  20. Neutron absorbing room temperature vulcanizable silicone rubber compositions

    DOE Patents [OSTI]

    Zoch, Harold L.

    1979-11-27

    A neutron absorbing composition comprising a one-component room temperature vulcanizable silicone rubber composition or a two-component room temperature vulcanizable silicone rubber composition in which the composition contains from 25 to 300 parts by weight based on the base silanol or vinyl containing diorganopolysiloxane polymer of a boron compound or boron powder as the neutron absorbing ingredient. An especially useful boron compound in this application is boron carbide.

  1. Neutron reflecting supermirror structure

    DOE Patents [OSTI]

    Wood, James L.

    1992-01-01

    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. Neutron reflecting supermirror structure

    DOE Patents [OSTI]

    Wood, J.L.

    1992-12-01

    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.

  3. Study of optical Laue diffraction

    SciTech Connect (OSTI)

    Chakravarthy, Giridhar E-mail: aloksharan@email.com; Allam, Srinivasa Rao E-mail: aloksharan@email.com; Satyanarayana, S. V. M. E-mail: aloksharan@email.com; Sharan, Alok E-mail: aloksharan@email.com

    2014-10-15

    We present the study of the optical diffraction pattern of one and two-dimensional gratings with defects, designed using desktop pc and printed on OHP sheet using laser printer. Gratings so prepared, using novel low cost technique provides good visual aid in teaching. Diffraction pattern of the monochromatic light (632.8nm) from the grating so designed is similar to that of x-ray diffraction pattern of crystal lattice with point defects in one and two-dimensions. Here both optical and x-ray diffractions are Fraunhofer. The information about the crystalline lattice structure and the defect size can be known.

  4. Electrically-programmable diffraction grating

    DOE Patents [OSTI]

    Ricco, Antonio J.; Butler, Michael A.; Sinclair, Michael B.; Senturia, Stephen D.

    1998-01-01

    An electrically-programmable diffraction grating. The programmable grating includes a substrate having a plurality of electrodes formed thereon and a moveable grating element above each of the electrodes. The grating elements are electrostatically programmable to form a diffraction grating for diffracting an incident beam of light as it is reflected from the upper surfaces of the grating elements. The programmable diffraction grating, formed by a micromachining process, has applications for optical information processing (e.g. optical correlators and computers), for multiplexing and demultiplexing a plurality of light beams of different wavelengths (e.g. for optical fiber communications), and for forming spectrometers (e.g. correlation and scanning spectrometers).

  5. NEUTRONIC REACTORS

    DOE Patents [OSTI]

    Vernon, H.C.

    1959-01-13

    A neutronic reactor of the heterogeneous, fluid cooled tvpe is described. The reactor is comprised of a pressure vessel containing the moderator and a plurality of vertically disposed channels extending in spaced relationship through the moderator. Fissionable fuel material is placed within the channels in spaced relationship thereto to permit circulation of the coolant fluid. Separate means are provided for cooling the moderator and for circulating a fluid coolant thru the channel elements to cool the fuel material.

  6. Pressure-Induced Structural Phase Transition in CeNi: X-ray and Neutron Scattering Studies and First-Principles Calculations

    SciTech Connect (OSTI)

    Mirmelstein, A.; Podlesnyak, Andrey A.; dos Santos, Antonio M.; Ehlers, Georg; Kerbel, O.; Matvienko, V.; Sefat, A. S.; Saporov, B.; Halder, G. J.; Tobin, J. G.

    2015-08-03

    The pressure-induced structural phase transition in the intermediate-valence compound CeNi has been investigated by x-ray and neutron powder diffraction techniques. It is shown that the structure of the pressure-induced CeNi phase (phases) can be described in terms of the Pnma space group. Equations of state for CeNi on both sides of the phase transition are derived and an approximate P-T phase diagram is suggested for P<8 GPa and T<300 K. The observed Cmcm?Pnma structural transition is then analyzed using density functional theory calculations, which successfully reproduce the ground state volume, the phase transition pressure, and the volume collapse associated with the phase transition.

  7. Pressure-Induced Structural Phase Transition in CeNi: X-ray and Neutron Scattering Studies and First-Principles Calculations

    SciTech Connect (OSTI)

    Mirmelstein, A.; Podlesnyak, Andrey A.; dos Santos, Antonio M.; Ehlers, Georg; Kerbel, O.; Matvienko, V.; Sefat, A. S.; Saporov, B.; Halder, G. J.; Tobin, J. G.

    2015-08-03

    The pressure-induced structural phase transition in the intermediate-valence compound CeNi has been investigated by x-ray and neutron powder diffraction techniques. It is shown that the structure of the pressure-induced CeNi phase (phases) can be described in terms of the Pnma space group. Equations of state for CeNi on both sides of the phase transition are derived and an approximate P-T phase diagram is suggested for P<8 GPa and T<300 K. The observed Cmcm→Pnma structural transition is then analyzed using density functional theory calculations, which successfully reproduce the ground state volume, the phase transition pressure, and the volume collapse associated with the phase transition.

  8. Pressure-Induced Structural Phase Transition in CeNi: X-ray and Neutron Scattering Studies and First-Principles Calculations

    DOE PAGES-Beta [OSTI]

    Mirmelstein, A.; Podlesnyak, Andrey A.; dos Santos, Antonio M.; Ehlers, Georg; Kerbel, O.; Matvienko, V.; Sefat, A. S.; Saporov, B.; Halder, G. J.; Tobin, J. G.

    2015-08-03

    The pressure-induced structural phase transition in the intermediate-valence compound CeNi has been investigated by x-ray and neutron powder diffraction techniques. It is shown that the structure of the pressure-induced CeNi phase (phases) can be described in terms of the Pnma space group. Equations of state for CeNi on both sides of the phase transition are derived and an approximate P-T phase diagram is suggested for P<8 GPa and T<300 K. The observed Cmcm→Pnma structural transition is then analyzed using density functional theory calculations, which successfully reproduce the ground state volume, the phase transition pressure, and the volume collapse associated withmore » the phase transition.« less

  9. SHARP Neutronics Expanded

    Energy.gov [DOE]

    The SHARP neutronics module, PROTEUS, includes neutron and gamma transport solvers and cross-section processing tools as well as the capability for depletion and fuel cycle analysis.

  10. NEUTRON SOURCE

    DOE Patents [OSTI]

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

    1959-01-13

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

  11. NEUTRON COUNTER

    DOE Patents [OSTI]

    Curtis, C.D.; Carlson, R.L.; Tubinis, M.P.

    1958-07-29

    An ionization chamber instrument is described for cylindrical electrodes with an ionizing gag filling the channber. The inner electrode is held in place by a hermetic insulating seal at one end of the outer electrode, the other end of the outer electrode being closed by a gas filling tube. The outer surface of the inner electrode is coated with an active material which is responsive to neutron bombardment, such as uranium235 or boron-10, to produce ionizing radiations in the gas. The transverse cross sectional area of the inner electrode is small in relation to that of the channber whereby substantially all of the radiations are directed toward the outer electrode.

  12. Preparation of superconductor precursor powders

    DOE Patents [OSTI]

    Bhattacharya, R.

    1998-08-04

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic and/or reduced particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of all metals in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products. 7 figs.

  13. Preparation of superconductor precursor powders

    DOE Patents [OSTI]

    Bhattacharya, Raghunath; Blaugher, Richard D.

    1995-01-01

    A process for the preparation of a precursor metallic powder composition for use in the subsequent formation of a superconductor. The process comprises the steps of providing an electrodeposition bath comprising an electrolyte medium and a cathode substrate electrode, and providing to the bath one or more soluble salts of one or more respective metals, such as nitrate salts of thallium, barium, calcium, and copper, which are capable of exhibiting superconductor properties upon subsequent appropriate treatment. The bath is continually energized to cause the metallic particles formed at the electrode to drop as a powder from the electrode into the bath, and this powder, which is a precursor powder for superconductor production, is recovered from the bath for subsequent treatment. The process permits direct inclusion of thallium in the preparation of the precursor powder, and yields an amorphous product mixed on an atomic scale to thereby impart inherent high reactivity. Superconductors which can be formed from the precursor powder include pellet and powder-in-tube products.

  14. Boron-copper neutron absorbing material and method of preparation

    DOE Patents [OSTI]

    Wiencek, Thomas C.; Domagala, Robert F.; Thresh, Henry

    1991-01-01

    A composite, copper clad neutron absorbing material is comprised of copper powder and boron powder enriched with boron 10. The boron 10 content can reach over 30 percent by volume, permitting a very high level of neutron absorption. The copper clad product is also capable of being reduced to a thickness of 0.05 to 0.06 inches and curved to a radius of 2 to 3 inches, and can resist temperatures of 900.degree. C. A method of preparing the material includes the steps of compacting a boron-copper powder mixture and placing it in a copper cladding, restraining the clad assembly in a steel frame while it is hot rolled at 900.degree. C. with cross rolling, and removing the steel frame and further rolling the clad assembly at 650.degree. C. An additional sheet of copper can be soldered onto the clad assembly so that the finished sheet can be cold formed into curved shapes.

  15. Silica powders for powder evacuated thermal insulating panel and method

    SciTech Connect (OSTI)

    Harris, Michael T.; Basaran, Osman A.; Kollie, Thomas G.; Weaver, Fred J.

    1995-01-01

    A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2/ g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

  16. Silica powders for powder evacuated thermal insulating panel and method

    SciTech Connect (OSTI)

    Harris, M.T.; Basaran, O.A.; Kollie, T.G.; Weaver, F.J.

    1996-01-02

    A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm{sup 3} and an external surface area in the range of about 90 to 600 m{sup 2}/g is described. The silica powders are prepared by reacting a tetraalkyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders. 2 figs.

  17. Silica powders for powder evacuated thermal insulating panel and method

    SciTech Connect (OSTI)

    Harris, Michael T.; Basaran, Osman A.; Kollie, Thomas G.; Weaver, Fred J.

    1994-01-01

    A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2 /g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

  18. Silica powders for powder evacuated thermal insulating panel and method

    SciTech Connect (OSTI)

    Harris, Michael T.; Basaran, Osman A.; Kollie, Thomas G.; Weaver, Fred J.

    1996-01-01

    A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2/ g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

  19. Method for molding ceramic powders

    DOE Patents [OSTI]

    Janney, Mark A.

    1990-01-01

    A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant for the metal-containing powder, and a monomer solution. The monomer solution includes at least one multifunctional monomer, a free-radical initiator, and an organic solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, whereafter the product may be sintered.

  20. Method for molding ceramic powders

    DOE Patents [OSTI]

    Janney, M.A.

    1990-01-16

    A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant for the metal-containing powder, and a monomer solution. The monomer solution includes at least one multifunctional monomer, a free-radical initiator, and an organic solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, where after the product may be sintered.

  1. Electrically-programmable diffraction grating

    DOE Patents [OSTI]

    Ricco, A.J.; Butler, M.A.; Sinclair, M.B.; Senturia, S.D.

    1998-05-26

    An electrically-programmable diffraction grating is disclosed. The programmable grating includes a substrate having a plurality of electrodes formed thereon and a moveable grating element above each of the electrodes. The grating elements are electrostatically programmable to form a diffraction grating for diffracting an incident beam of light as it is reflected from the upper surfaces of the grating elements. The programmable diffraction grating, formed by a micromachining process, has applications for optical information processing (e.g. optical correlators and computers), for multiplexing and demultiplexing a plurality of light beams of different wavelengths (e.g. for optical fiber communications), and for forming spectrometers (e.g. correlation and scanning spectrometers). 14 figs.

  2. Pressure dependence of the magnetic order in CrAs: A neutron...

    Office of Scientific and Technical Information (OSTI)

    Pressure dependence of the magnetic order in CrAs: A neutron diffraction investigation Citation Details In-Document Search Title: Pressure dependence of the magnetic order in CrAs:...

  3. Rotary powder feed through apparatus

    DOE Patents [OSTI]

    Lewis, Gary K. (Los Alamos, NM); Less, Richard M. (Los Alamos, NM)

    2001-01-01

    A device for increasing the uniformity of solids within a solids fabrication system, such as a direct light fabrication (DLF) system in which gas entrained powders are passed through the focal point of a moving high-power light which fuses the particles in the powder to a surface being built up in layers. The invention provides a feed through interface wherein gas entrained powders input from stationary input lines are coupled to a rotating head of the fabrication system. The invention eliminates the need to provide additional slack in the feed lines to accommodate head rotation, and therefore reduces feed line bending movements which induce non-uniform feeding of gas entrained powder to a rotating head.

  4. Neutron reflecting supermirror structure

    DOE Patents [OSTI]

    Wood, James L.

    1992-01-01

    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.

  5. NEUTRONIC REACTORS

    DOE Patents [OSTI]

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

    1958-10-14

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

  6. NEUTRONIC REACTOR

    DOE Patents [OSTI]

    Stewart, H.B.

    1958-12-23

    A nuclear reactor of the type speclfically designed for the irradiation of materials is discussed. In this design a central cyllndrical core of moderating material ls surrounded by an active portlon comprlsed of an annular tank contalning fissionable material immersed ln a liquid moderator. The active portion ls ln turn surrounded by a reflector, and a well ls provided in the center of the core to accommodate the materlals to be irradiated. The over-all dimensions of the core ln at least one plane are equal to or greater than twice the effective slowing down length and equal to or less than twlce the effective diffuslon length for neutrons in the core materials.

  7. Powder collection apparatus/method

    DOE Patents [OSTI]

    Anderson, I.E.; Terpstra, R.L.; Moore, J.A.

    1994-01-11

    Device for separating and collecting ultrafine atomized powder from the gas stream of a gas atomizing apparatus comprises a housing having an interior wall oriented at an angle relative to horizontal so as to form a downwardly converging, conical expansion chamber, an inlet conduit communicated to the expansion chamber proximate an upper region thereof for receiving the gas stream, and an outlet proximate a lower region of the expansion chamber. The inlet conduit is oriented at a compound inclined angle (with respect to horizontal) selected to promote separation and collection of powder from the gas stream in the expansion chamber. The compound angle comprises a first entrance angle that is greater than the angle of repose of the powder on the housing interior wall such that any powder accumulation in the inlet conduit tends to flow down the wall toward the outlet. The second angle is selected generally equal to the angle of the housing interior wall measured from the same horizontal plane so as to direct the gas stream into the expansion chamber generally tangent to the housing interior wall to establish a downward swirling gas stream flow in the expansion chamber. A powder collection container is communicated to the outlet of the expansion chamber to collect the powder for further processing. 4 figures.

  8. High precision thermal neutron detectors

    SciTech Connect (OSTI)

    Radeka, V.; Schaknowski, N.A.; Smith, G.C.; Yu, B.

    1994-12-31

    Two-dimensional position sensitive detectors are indispensable in neutron diffraction experiments for determination of molecular and crystal structures in biology, solid-state physics and polymer chemistry. Some performance characteristics of these detectors are elementary and obvious, such as the position resolution, number of resolution elements, neutron detection efficiency, counting rate and sensitivity to gamma-ray background. High performance detectors are distinguished by more subtle characteristics such as the stability of the response (efficiency) versus position, stability of the recorded neutron positions, dynamic range, blooming or halo effects. While relatively few of them are needed around the world, these high performance devices are sophisticated and fairly complex, their development requires very specialized efforts. In this context, we describe here a program of detector development, based on {sup 3}He filled proportional chambers, which has been underway for some years at the Brookhaven National Laboratory. Fundamental approaches and practical considerations are outlined that have resulted in a series of high performance detectors with the best known position resolution, position stability, uniformity of response and reliability over time, for devices of this type.

  9. Tritium and neutron measurements from deuterated Pd-Si

    SciTech Connect (OSTI)

    Claytor, T.N.; Tuggle, D.G.; Menlove, H.O.; Seeger, P.A.; Doty, W.R.; Rohwer, R.K. (Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States))

    1991-05-10

    Evidence has been found for tritium and neutron production in palladium and silicon stacks when pulsed with a high electric current. These palladium-silicon stacks consist of alternating layers of pressed palladium and silicon powder. A pulsed high electric current is thought to promote non-equilibrium conditions important for tritium and neutron production. More than 2000 hours of neutron counting time has been accumulated in a underground, low background, environment with high efficiency counters (21%). Neutron emission has occurred as infrequent bursts or as low level emission lasting for up to 20 hours. In eight of 30 cells, excess tritium greater than 3 sigma has been observed. In each of these measurements, with the powder system, the ratio of tritium detected to total integrated total neutrons inferred has been anomalously high. Recent cells have shown reproducible tritium generation at a level of about 0.5 nCi/hr. Several hydrogen and air control cells have been run with no anomalous excess tritium or neutron emission above background. A singificant amount of the total palladium inventory (18%) has been checked for tritium contamination by three independent means.

  10. Tritium and neutron measurements from deuterated Pd-Si

    SciTech Connect (OSTI)

    Claytor, T.N.; Tuggle, D.G.; Menlove, H.O.; Seeger, P.A.; Doty, W.R.; Rohwer, R.K.

    1990-01-01

    Evidence has been found for tritium and neutron production in palladium and silicon stacks when pulsed with a high electric current. These palladium-silicon stacks consist of alternating layers of pressed palladium and silicon powder. A pulsed high electric current is thought to promote non equilibrium conditions important for tritium and neutron production. More than 2000 hours of neutron counting time has been accumulated in a underground, low background, environment with high efficiency counters (21%). Neutron emission has occurred as infrequent burst or as low level emission lasting for up to 20 hours. In eight of 30 cells, excess tritium greater than 3 sigma has been observed. In each of these measurements, with the powder system, the ratio of tritium detected to total integrated total neutrons inferred has been anomalously high. Recent cells have shown reproducible tritium generation at a level of about 0.5 nCi/hr. Several hydrogen and air control cells have been run with no anomalous excess tritium or neutron emission above background. A significant amount of the total palladium inventory (18%) has been checked for tritium contamination by three independent means. 12 refs., 6 figs., 2 tabs.

  11. Ceramic oxide powders and the formation thereof

    DOE Patents [OSTI]

    Katz, Joseph L.; Hung, Cheng-Hung

    1993-01-01

    Ceramic oxide powders and a method for their preparation. Ceramic oxide powders are obtained using a flame process whereby two or more precursors of ceramic oxides are introduced into a counterflow diffusion flame burner wherein said precursors are converted into ceramic oxide powders. The morphology, particle size, and crystalline form of the ceramic oxide powders are determined by process conditions.

  12. Ceramic oxide powders and the formation thereof

    DOE Patents [OSTI]

    Katz, J.L.; Chenghung Hung.

    1993-12-07

    Ceramic oxide powders and a method for their preparation. Ceramic oxide powders are obtained using a flame process whereby two or more precursors of ceramic oxides are introduced into a counterflow diffusion flame burner wherein said precursors are converted into ceramic oxide powders. The morphology, particle size, and crystalline form of the ceramic oxide powders are determined by process conditions. 14 figures.

  13. Neutron range spectrometer

    DOE Patents [OSTI]

    Manglos, Stephen H.

    1989-06-06

    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.

  14. X-ray diffraction study of crystalline barium titanate ceramics

    SciTech Connect (OSTI)

    Zali, Nurazila Mat; Mahmood, Che Seman; Mohamad, Siti Mariam; Foo, Choo Thye; Murshidi, Julie Adrianny

    2014-02-12

    In this study, BaTiO{sub 3} ceramics have been prepared via solid-state reaction method. The powders were calcined for 2 hours at different temperatures ranging from 600C to 1200C. Using X-ray diffraction with a Rietveld analysis, the phase formation and crystal structure of the BaTiO{sub 3} powders were studied. Change in crystallite size and tetragonality as a function of calcination temperature were also discussed. It has been found that the formation of pure perovskite phase of BaTiO{sub 3} began at calcination condition of 1000 C for 2 hours. The crystal structure of BaTiO{sub 3} formed is in the tetragonal structure. The second phases of BaCO{sub 3} and TiO{sub 2} existed with calcination temperature below 1000 C. Purity, crystallite size and tetragonality of BaTiO{sub 3} powders were found to increase with increasing calcination temperature.

  15. NEUTRONIC REACTOR

    DOE Patents [OSTI]

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

    1958-09-01

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

  16. Diffraction encoded position measuring apparatus

    DOE Patents [OSTI]

    Tansey, Richard J.

    1991-01-01

    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.

  17. Diffraction encoded position measuring apparatus

    DOE Patents [OSTI]

    Tansey, R.J.

    1991-09-24

    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.

  18. Neutron streak camera

    DOE Patents [OSTI]

    Wang, C.L.

    1983-09-13

    Disclosed is an apparatus for improved sensitivity and time resolution of a neutron measurement. The detector is provided with an electrode assembly having a neutron sensitive cathode which emits relatively low energy secondary electrons. The neutron sensitive cathode has a large surface area which provides increased sensitivity by intercepting a greater number of neutrons. The cathode is also curved to compensate for differences in transit time of the neutrons emanating from the point source. The slower speeds of the secondary electrons emitted from a certain portion of the cathode are matched to the transit times of the neutrons impinging thereupon. 4 figs.

  19. Neutron streak camera

    DOE Patents [OSTI]

    Wang, Ching L.

    1983-09-13

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

  20. Layered semiconductor neutron detectors

    DOE Patents [OSTI]

    Mao, Samuel S; Perry, Dale L

    2013-12-10

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

  1. Neutron streak camera

    DOE Patents [OSTI]

    Wang, C.L.

    1981-05-14

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

  2. Organic metal neutron detector

    DOE Patents [OSTI]

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

    1984-11-21

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

  3. Spallation Neutron Source | Neutron Science at ORNL

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    The recently commissioned 11 Tesla horizontal field magnet at GP-SANS will enable advanced neutron scattering research. Credit: Genevieve MartinORNL. 11 Tesla Magnet Commissioned ...

  4. Neutronic Reactor Design to Reduce Neutron Loss

    DOE Patents [OSTI]

    Miles, F. T.

    1961-05-01

    A nuclear reactor construction is described in which an unmoderated layer of the fissionable material is inserted between the moderated portion of the reactor core and the core container steel wall. The wall is surrounded by successive layers of pure fertile material and moderator containing fertile material. The unmoderated layer of the fissionable material will insure that a greater portion of fast neutrons will pass through the steel wall than would thermal neutrons. Since the steel has a smaller capture cross section for the fast neutrons, greater nunnbers of neutrons will pass into the blanket, thereby increasing the over-all efficiency of the reactor. (AEC)

  5. NEUTRONIC REACTOR DESIGN TO REDUCE NEUTRON LOSS

    DOE Patents [OSTI]

    Mills, F.T.

    1961-05-01

    A nuclear reactor construction is described in which an unmoderated layer of the fissionable material is inserted between the moderated portion of the reactor core and the core container steel wall which is surrounded by successive layers of pure fertile material and fertile material having moderator. The unmoderated layer of the fissionable material will insure that a greater portion of fast neutrons will pass through the steel wall than would thermal neutrons. As the steel has a smaller capture cross-section for the fast neutrons, then greater numbers of the neutrons will pass into the blanket thereby increasing the over-all efficiency of the reactor.

  6. Neutron scattering study on cathode LiMn{sub 2}O{sub 4} and solid electrolyte 5(Li{sub 2}O)(P{sub 2}O{sub 5})

    SciTech Connect (OSTI)

    Kartini, E. Putra, Teguh P. Jahya, A. K. Insani, A.; Adams, S.

    2014-09-30

    Neutron scattering is very important technique in order to investigate the energy storage materials such as lithium-ion battery. The unique advantages, neutron can see the light atoms such as Hydrogen, Lithium, and Oxygen, where those elements are negligible by other corresponding X-ray method. On the other hand, the energy storage materials, such as lithium ion battery is very important for the application in the electric vehicles, electronic devices or home appliances. The battery contains electrodes (anode and cathode), and the electrolyte materials. There are many challenging to improve the existing lithium ion battery materials, in order to increase their life time, cyclic ability and also its stability. One of the most scientific challenging is to investigate the crystal structure of both electrode and electrolyte, such as cathodes LiCoO{sub 2}, LiMn{sub 2}O{sub 4} and LiFePO{sub 4}, and solid electrolyte Li{sub 3}PO{sub 4}. Since all those battery materials contain Lithium ions and Oxygen, the used of neutron scattering techniques to study their structure and related properties are very important and indispensable. This article will review some works of investigating electrodes and electrolytes, LiMn{sub 2}O{sub 4} and 5(Li{sub 2}O)(P{sub 2}O{sub 5}), by using a high resolution powder diffraction (HRPD) at the multipurpose research reactor, RSG-Sywabessy of the National Nuclear Energy Agency (BATAN), Indonesia.

  7. PROCESS OF FORMING POWDERED MATERIAL

    DOE Patents [OSTI]

    Glatter, J.; Schaner, B.E.

    1961-07-14

    A process of forming high-density compacts of a powdered ceramic material is described by agglomerating the powdered ceramic material with a heat- decompossble binder, adding a heat-decompossble lubricant to the agglomerated material, placing a quantity of the material into a die cavity, pressing the material to form a compact, pretreating the compacts in a nonoxidizing atmosphere to remove the binder and lubricant, and sintering the compacts. When this process is used for making nuclear reactor fuel elements, the ceramic material is an oxide powder of a fissionsble material and after forming, the compacts are placed in a cladding tube which is closed at its ends by vapor tight end caps, so that the sintered compacts are held in close contact with each other and with the interior wall of the cladding tube.

  8. Spatial resolution of diffraction tomography

    SciTech Connect (OSTI)

    Dickens, T.A.; Winbow, G.A.

    1997-01-01

    Diffraction tomography is an imaging technique applicable to crosshole seismic data and aimed at achieving optimal spatial resolution away from the borehole. In principle the method can form acoustic images equivalent to extending acoustic well logs away from the wellbore and into the formation with a spatial resolution less than one wavelength of the radiation employed to gather the crosshole data. This paper reports on the capability of diffraction tomography to produce high-resolution reconstructions of simple targets from limited-view-angle data. The goal is to quantify the resolution and velocity-reconstruction capability of diffraction tomography with realistic source{endash}receiver geometries. Simple targets (disks and low-contrast sequences of layers) are used for this study. The scattering from these targets can be calculated without approximation, making them ideal test cases for the algorithm. The resolution capability of diffraction tomography is determined to be on the order of one wavelength for several experimental geometries. It is shown that the image-formation characteristics of diffraction tomography, in terms of its ability to determine object boundaries and velocities, are closely related to the experimental geometry. Reflection and vertical seismic profiling (VSP) experiments tend to reproduce boundaries well, while crosshole experiments give the best overall reconstruction of both target boundaries and velocity. The quantitative accuracy of the velocity reconstruction depends upon the match between the spatial-frequency content of the object and the spatial-frequency response of the algorithm. For some targets, the velocity cannot be correctly reproduced from limited-view-angle data. {copyright} {ital 1997 Acoustical Society of America.}

  9. Dose equivalent neutron dosimeter

    DOE Patents [OSTI]

    Griffith, Richard V.; Hankins, Dale E.; Tomasino, Luigi; Gomaa, Mohamed A. M.

    1983-01-01

    A neutron dosimeter is disclosed which provides a single measurements 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 containing 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. The density of conversion material in the radiator layer is of an amount which is chosen so that the density of tracks produced in the detecting sheet is proportional to the biological damage done by neutrons, regardless of whether the tracks are produced as the result of moderate energy neutrons striking the radiator layer or as the result of higher energy neutrons striking the sheet of track etch material.

  10. Pulsed-neutron monochromator

    DOE Patents [OSTI]

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

    1985-01-01

    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.

  11. Ultrafast neutron detector

    DOE Patents [OSTI]

    Wang, C.L.

    1985-06-19

    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.

  12. Neutron dose equivalent meter

    DOE Patents [OSTI]

    Olsher, Richard H.; Hsu, Hsiao-Hua; Casson, William H.; Vasilik, Dennis G.; Kleck, Jeffrey H.; Beverding, Anthony

    1996-01-01

    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.

  13. Pulsed-neutron monochromator

    DOE Patents [OSTI]

    Mook, H.A. Jr.

    1984-01-01

    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.

  14. ULTRASONIC NEUTRON DOSIMETER

    DOE Patents [OSTI]

    Truell, R.; de Klerk, J.; Levy, P.W.

    1960-02-23

    A neutron dosimeter is described which utilizes ultrasonic waves in the megacycle region for determination of the extent of neutron damage in a borosilicate glass through ultrasonic wave velocity and attenuation measurements before and after damage.

  15. Fast-neutron solid-state dosimeter

    DOE Patents [OSTI]

    Kecker, K.H.; Haywood, F.F.; Perdue, P.T.; Thorngate, J.H.

    1975-07-22

    This patent relates to an improved fast-neutron solid-state dosimeter that does not require separation of materials before it can be read out, that utilizes materials that do not melt or otherwise degrade at about 300$sup 0$C readout temperature, that provides a more efficient dosimeter, and that can be reused. The dosimeters are fabricated by intimately mixing a TL material, such as CaSO$sub 4$:Dy, with a powdered polyphenyl, such as p-sexiphenyl, and hot- pressing the mixture to form pellets, followed by out-gassing in a vacuum furnace at 150$sup 0$C prior to first use dosimeters. (auth)

  16. Intense fusion neutron sources

    SciTech Connect (OSTI)

    Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

    2010-04-15

    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 10{sup 15}-10{sup 21} neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 10{sup 20} neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the

  17. Neutrons - 88-Inch Cyclotron

    U.S. Department of Energy (DOE) all 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 neutrons/cm^2/sec. For more information, please contact Mike Johnson via e-mail at MBJohnson@lbl.gov, or by phone at at (510) 486-4389.

  18. Advanced neutron absorber materials

    DOE Patents [OSTI]

    Branagan, Daniel J.; Smolik, Galen R.

    2000-01-01

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

  19. Arsenic activation neutron detector

    DOE Patents [OSTI]

    Jacobs, Eddy L.

    1981-01-01

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

  20. Prototype Neutron Energy Spectrometer

    SciTech Connect (OSTI)

    Stephen Mitchell, Sanjoy Mukhopadhyay, Richard Maurer, Ronald Wolff

    2010-06-16

    The project goals are: (1) Use three to five pressurized helium tubes with varying polyethylene moderators to build a neutron energy spectrometer that is most sensitive to the incident neutron energy of interest. Neutron energies that are of particular interest are those from the fission neutrons (typically around 1-2 MeV); (2) Neutron Source Identification - Use the neutron energy 'selectivity' property as a tool to discriminate against other competing processes by which neutrons are generated (viz. Cosmic ray induced neutron production [ship effect], [a, n] reactions); (3) Determine the efficiency as a function of neutron energy (response function) of each of the detectors, and thereby obtain the composite neutron energy spectrum from the detector count rates; and (4) Far-field data characterization and effectively discerning shielded fission source. Summary of the presentation is: (1) A light weight simple form factor compact neutron energy spectrometer ready to be used in maritime missions has been built; (2) Under laboratory conditions, individual Single Neutron Source Identification is possible within 30 minutes. (3) Sources belonging to the same type of origin viz., (a, n), fission, cosmic cluster in the same place in the 2-D plot shown; and (4) Isotopes belonging to the same source origin like Cm-Be, Am-Be (a, n) or Pu-239, U-235 (fission) do have some overlap in the 2-D plot.

  1. Arsenic activation neutron detector

    DOE Patents [OSTI]

    Jacobs, E.L.

    1980-01-28

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

  2. Eshelby twist and correlation effects in diffraction from nanocrystals

    SciTech Connect (OSTI)

    Leonardi, A.; Scardi, P.; Ryu, S.; Pugno, N. M.

    2015-04-28

    Molecular dynamics simulations were used to model the Eshelby dislocation inside Pd and Ir nanowires and to predict the powder diffraction pattern using the Debye scattering equation. We find that the ideal dislocation solution by Eshelby is in good agreement with the observed twist angle and deviatoric strain, even though it ignores both the splitting of the Eshelby dislocation into two partials and surface stress. Surface stress plays a significant role only for nanorods with small aspect ratio (?1:1). We also find that Wilson's prediction on the diffraction peak broadening for the Eshelby dislocation is overestimated because it ignores the fact that the Eshelby twist relaxes the deviatoric strain. Moreover, the twist loosens the correlation along the nanorod, causing additional line profile broadening, which is read by diffraction as a decrease of coherent domain size when the total twist angle is bigger than 1.5. Overall, our findings suggest a novel way to predict and analyze the dislocations as well as the resulting strain fields in the twisted nanocrystalline rods.

  3. Polymer quenched prealloyed metal powder

    DOE Patents [OSTI]

    Hajaligol, Mohammad R.; Fleischhauer, Grier; German, Randall M.

    2001-01-01

    A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3 % Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

  4. Solid state neutron detector and method for use

    DOE Patents [OSTI]

    Doty, F. Patrick; Zwieback, Ilya; Ruderman, Warren

    2002-01-01

    Crystals of lithium tetraborate or alpha-barium borate had been found to be neutron detecting materials. The crystals are prepared using known crystal growing techniques, wherein the process does not include the common practice of using a fluxing agent, such as sodium oxide or sodium fluoride, to reduce the melting temperature of the crystalline compound. Crystals prepared by this method can be sliced into thin single or polycrystalline wafers, or ground to a powder and prepared as a sintered compact or a print paste, and then configured with appropriate electronic hardware, in order to function as neutron detectors.

  5. Neutron scatter camera

    DOE Patents [OSTI]

    Mascarenhas, Nicholas; Marleau, Peter; Brennan, James S.; Krenz, Kevin D.

    2010-06-22

    An instrument that will directly image the fast fission neutrons from a special nuclear material source has been described. This instrument can improve the signal to background compared to non imaging neutron detection techniques by a factor given by ratio of the angular resolution window to 4.pi.. In addition to being a neutron imager, this instrument will also be an excellent neutron spectrometer, and will be able to differentiate between different types of neutron sources (e.g. fission, alpha-n, cosmic ray, and D-D or D-T fusion). Moreover, the instrument is able to pinpoint the source location.

  6. High energy neutron dosimeter

    DOE Patents [OSTI]

    Rai, K.S.F.

    1994-01-11

    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.

  7. Organic metal neutron detector

    DOE Patents [OSTI]

    Butler, Michael A.; Ginley, David S.

    1987-01-01

    A device for detecting neutrons comprises a layer of conductive polymer sandwiched between electrodes, which may be covered on each face with a neutron transmissive insulating material layer. Conventional electrodes are used for a non-imaging integrating total neutron fluence-measuring embodiment, while wire grids are used in an imaging version of the device. The change in conductivity of the polymer after exposure to a neutron flux is determined in either case to provide the desired data. Alternatively, the exposed conductive polymer layer may be treated with a chemical reagent which selectively binds to the sites altered by neutrons to produce an image of the flux detected.

  8. PERSONNEL NEUTRON DOSIMETER

    DOE Patents [OSTI]

    Fitzgerald, J.J.; Detwiler, C.G. Jr.

    1960-05-24

    A description is given of a personnel neutron dosimeter capable of indicating the complete spectrum of the neutron dose received as well as the dose for each neutron energy range therein. The device consists of three sets of indium foils supported in an aluminum case. The first set consists of three foils of indium, the second set consists of a similar set of indium foils sandwiched between layers of cadmium, whereas the third set is similar to the second set but is sandwiched between layers of polyethylene. By analysis of all the foils the neutron spectrum and the total dose from neutrons of all energy levels can be ascertained.

  9. Semiconductor neutron detector

    DOE Patents [OSTI]

    Ianakiev, Kiril D.; Littlewood, Peter B.; Blagoev, Krastan B.; Swinhoe, Martyn T.; Smith, James L.; Sullivan, Clair J.; Alexandrov, Boian S.; Lashley, Jason Charles

    2011-03-08

    A neutron detector has a compound of lithium in a single crystal form as a neutron sensor element. The lithium compound, containing improved charge transport properties, is either lithium niobate or lithium tantalate. The sensor element is in direct contact with a monitor that detects an electric current. A signal proportional to the electric current is produced and is calibrated to indicate the neutrons sensed. The neutron detector is particularly useful for detecting neutrons in a radiation environment. Such radiation environment may, e.g. include gamma radiation and noise.

  10. High energy neutron dosimeter

    DOE Patents [OSTI]

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

    1994-01-01

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

  11. NEUTRON DENSITY CONTROL IN A NEUTRONIC REACTOR

    DOE Patents [OSTI]

    Young, G.J.

    1959-06-30

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

  12. Wetter for fine dry powder

    DOE Patents [OSTI]

    Hall, James E.; Williams, Everett H.

    1977-01-01

    A system for wetting fine dry powders such as bentonite clay with water or other liquids is described. The system includes a wetting tank for receiving water and a continuous flow of fine powder feed. The wetting tank has a generally square horizontal cross section with a bottom end closure in the shape of an inverted pyramid. Positioned centrally within the wetting tank is a flow control cylinder which is supported from the walls of the wetting tank by means of radially extending inclined baffles. A variable speed motor drives a first larger propeller positioned immediately below the flow control cylinder in a direction which forces liquid filling the tank to flow downward through the flow control cylinder and a second smaller propeller positioned below the larger propeller having a reverse pitch to oppose the flow of liquid being driven downward by the larger propeller.

  13. MESOSCALE SIMULATIONS OF POWDER COMPACTION

    SciTech Connect (OSTI)

    Lomov, Ilya; Fujino, Don; Antoun, Tarabay; Liu, Benjamin

    2009-12-28

    Mesoscale 3D simulations of shock compaction of metal and ceramic powders have been performed with an Eulerian hydrocode GEODYN. The approach was validated by simulating a well-characterized shock compaction experiment of a porous ductile metal. Simulation results using the Steinberg material model and handbook values for solid 2024 aluminum showed good agreement with experimental compaction curves and wave profiles. Brittle ceramic materials are not as well studied as metals, so a simple material model for solid ceramic (tungsten carbide) has been calibrated to match experimental compaction curves. Direct simulations of gas gun experiments with ceramic powders have been performed and showed good agreement with experimental data. The numerical shock wave profile has same character and thickness as that measured experimentally using VISAR. The numerical results show reshock states above the single-shock Hugoniot line as observed in experiments. We found that for good quantitative agreement with experiments 3D simulations are essential.

  14. Fiber optic diffraction grating maker

    DOE Patents [OSTI]

    Deason, V.A.; Ward, M.B.

    1991-05-21

    A compact and portable diffraction grating maker is comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent beam splitters, and collimating lenses or mirrors directing the split beam at an appropriate photosensitive material. The collimating optics, the output ends of the fiber optic coupler and the photosensitive plate holder are all mounted on an articulated framework so that the angle of intersection of the beams can be altered at will without disturbing the spatial filter, collimation or beam quality, and assuring that the beams will always intersect at the position of the plate. 4 figures.

  15. Fiber optic diffraction grating maker

    DOE Patents [OSTI]

    Deason, Vance A.; Ward, Michael B.

    1991-01-01

    A compact and portable diffraction grating maker comprised of a laser beam, optical and fiber optics devices coupling the beam to one or more evanescent beam splitters, and collimating lenses or mirrors directing the split beam at an appropriate photosensitive material. The collimating optics, the output ends of the fiber optic coupler and the photosensitive plate holder are all mounted on an articulated framework so that the angle of intersection of the beams can be altered at will without disturbing the spatial filter, collimation or beam quality, and assuring that the beams will always intersect at the position of the plate.

  16. Ultrafast electron diffraction from aligned molecules

    SciTech Connect (OSTI)

    Centurion, Martin

    2015-08-17

    The aim of this project was to record time-resolved electron diffraction patterns of aligned molecules and to reconstruct the 3D molecular structure. The molecules are aligned non-adiabatically using a femtosecond laser pulse. A femtosecond electron pulse then records a diffraction pattern while the molecules are aligned. The diffraction patterns are then be processed to obtain the molecular structure.

  17. Lujan Neutron Scattering Center

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    responds to radiological incident August 27, 2012 The Laboratory is investigating the inadvertent spread of Technetium 99 by employees and contractors at the Lujan Neutron Scattering Center August 27, 2012-The Laboratory is investigating the inadvertent spread of Technetium 99 by employees and contractors at the Lujan Neutron Scattering Center at the Los Alamos Neutron Science Center (LANSCE), a multidisciplinary accelerator facility - 2 - used for both civilian and national security research.

  18. 2010 Neutron Review: ORNL Neutron Sciences Progress Report (Technical

    Office of Scientific and Technical Information (OSTI)

    Report) | SciTech Connect Technical Report: 2010 Neutron Review: ORNL Neutron Sciences Progress Report Citation Details In-Document Search Title: 2010 Neutron Review: ORNL Neutron Sciences Progress Report During 2010, the Neutron Sciences Directorate focused on producing world-class science, while supporting the needs of the scientific community. As the instrument, sample environment, and data analysis tools at High Flux Isotope Reactor (HFIR ) and Spallation Neutron Source (SNS) have grown

  19. Neutron detection apparatus

    DOE Patents [OSTI]

    Kopp, Manfred K.; Valentine, Kenneth H.

    1983-01-01

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

  20. Magnetization of neutron matter

    SciTech Connect (OSTI)

    Bigdeli, M.

    2011-09-21

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

  1. Fast Neutron Detection Evaluation

    SciTech Connect (OSTI)

    McKigney, Edward A.; Stange, Sy

    2014-03-17

    These slides present a summary of previous work, conclusions, and anticipated schedule for the conclusion of our fast neutron detection evaluation.

  2. Neutron and Nuclear Science News

    U.S. Department of Energy (DOE) all 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 LANSCE

  3. Improved neutron-gamma discrimination for a 6Li-glass neutron detector using digital signal analysis methods

    DOE PAGES-Beta [OSTI]

    Wang, Cai -Lin; Riedel, Richard A.

    2016-01-14

    A 6Li-glass scintillator (GS20) based neutron Anger camera was developed for time-of-flight single-crystal diffraction instruments at SNS. Traditional pulse-height analysis (PHA) for neutron-gamma discrimination (NGD) resulted in the neutron-gamma efficiency ratio (defined as NGD ratio) on the order of 104. The NGD ratios of Anger cameras need to be improved for broader applications including neutron reflectometers. For this purpose, five digital signal analysis methods of individual waveforms from PMTs were proposed using: i). pulse-amplitude histogram; ii). power spectrum analysis combined with the maximum pulse amplitude; iii). two event parameters (a1, b0) obtained from Wiener filter; iv). an effective amplitude (m)more » obtained from an adaptive least-mean-square (LMS) filter; and v). a cross-correlation (CC) coefficient between an individual waveform and a reference. The NGD ratios can be 1-102 times those from traditional PHA method. A brighter scintillator GS2 has better NGD ratio than GS20, but lower neutron detection efficiency. The ultimate NGD ratio is related to the ambient, high-energy background events. Moreover, our results indicate the NGD capability of neutron Anger cameras can be improved using digital signal analysis methods and brighter neutron scintillators.« less

  4. Trends in powder processing equipment

    SciTech Connect (OSTI)

    Sheppard, L.M.

    1993-05-01

    Spray drying is the most widely used process for producing particles. It is used in industries other than ceramics including food, chemicals, and pharmaceutical. The process involves the atomization of a liquid feed stock into a spray of droplets and contacting the droplets with hot air in a drying chamber. The sprays are produced by either rotary or nozzle atomizers. Evaporation of moisture from the droplets and formation of dry particles proceed under controlled temperature and airflow conditions. Powder is then discharged continuously from the drying chamber. Spray drying equipment is being improved to handle an ever-increasing number of applications. Several developments in particle-size reduction equipment are also described.

  5. Cation disorder in high-dose, neutron-irradiated spinel

    SciTech Connect (OSTI)

    Sickafus, K.E.; Larson, A.C.; Yu, N.

    1995-04-01

    The objective of this effort is to determine whether MgAl{sub 2}O{sub 4} spinel is a suitable ceramic for fusion applications. The crystal structures of MgAl{sub 2}O{sub 4} spinel single crystals irradiated to high neutron fluences [>5{times}10{sup 26} n/m{sup 2} (E{sub n}>0.1 MeV)] were examined by neutron diffraction. Crystal structure refinement of the highese dose sample indicated that the average scattering strength of the tetrahedral crystal sites decreased by {approx}20% while increasing by {approx}8% on octahedral sites.

  6. Compact neutron generator

    DOE Patents [OSTI]

    Leung, Ka-Ngo; Lou, Tak Pui

    2005-03-22

    A compact neutron generator has at its outer circumference a toroidal shaped plasma chamber in which a tritium (or other) plasma is generated. A RF antenna is wrapped around the plasma chamber. A plurality of tritium ion beamlets are extracted through spaced extraction apertures of a plasma electrode on the inner surface of the toroidal plasma chamber and directed inwardly toward the center of neutron generator. The beamlets pass through spaced acceleration and focusing electrodes to a neutron generating target at the center of neutron generator. The target is typically made of titanium tubing. Water is flowed through the tubing for cooling. The beam can be pulsed rapidly to achieve ultrashort neutron bursts. The target may be moved rapidly up and down so that the average power deposited on the surface of the target may be kept at a reasonable level. The neutron generator can produce fast neutrons from a T-T reaction which can be used for luggage and cargo interrogation applications. A luggage or cargo inspection system has a pulsed T-T neutron generator or source at the center, surrounded by associated gamma detectors and other components for identifying explosives or other contraband.

  7. Neutron capture therapies

    DOE Patents [OSTI]

    Yanch, Jacquelyn C.; Shefer, Ruth E.; Klinkowstein, Robert E.

    1999-01-01

    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.

  8. Process for the synthesis of iron powder

    DOE Patents [OSTI]

    Welbon, W.W.

    1983-11-08

    A process for preparing iron powder suitable for use in preparing the iron-potassium perchlorate heat-powder fuel mixture used in thermal batteries, comprises preparing a homogeneous, dense iron oxide hydroxide precipitate by homogeneous precipitation from an aqueous mixture of a ferric salt, formic or sulfuric acid, ammonium hydroxide and urea as precipitating agent; and then reducing the dense iron oxide hydroxide by treatment with hydrogen to prepare the iron powder. 2 figs.

  9. Process for the synthesis of iron powder

    DOE Patents [OSTI]

    Welbon, William W.

    1983-01-01

    A process for preparing iron powder suitable for use in preparing the iron-potassium perchlorate heat-powder fuel mixture used in thermal batteries, comprises preparing a homogeneous, dense iron oxide hydroxide precipitate by homogeneous precipitation from an aqueous mixture of a ferric salt, formic or sulfuric acid, ammonium hydroxide and urea as precipitating agent; and then reducing the dense iron oxide hydroxide by treatment with hydrogen to prepare the iron powder.

  10. Process for the synthesis of iron powder

    DOE Patents [OSTI]

    Not Available

    1982-03-06

    A process for preparing iron powder suitable for use in preparing the iron-potassium perchlorate heat-powder fuel mixture used in thermal batteries, comprises preparing a homogeneous, dense iron oxide hydroxide precipitate by homogeneous precipitation from an aqueous mixture of a ferric salt, formic or sulfuric acid, ammonium hydroxide and urea as precipitating agent; and then reducing the dense iron oxide hydroxide by treatment with hydrogen to prepare the iron powder.

  11. Pocked surface neutron detector

    DOE Patents [OSTI]

    McGregor, Douglas; Klann, Raymond

    2003-04-08

    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.

  12. Pulsed neutron detector

    DOE Patents [OSTI]

    Robertson, deceased, J. Craig; Rowland, Mark S.

    1989-03-21

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

  13. Ultrafine Hydrogen Storage Powders - Energy Innovation Portal

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    Hydrogen and Fuel Cell Hydrogen and Fuel Cell Energy Storage Energy Storage Find More Like This Return to Search Ultrafine Hydrogen Storage Powders Ames Laboratory Contact AMES ...

  14. METHOD OF PREPARATION OF MATERIAL FOR NEUTRON BOMBARDMENT

    DOE Patents [OSTI]

    Ura, C.L.; Sisman, O.; Briggs, R.B.

    1959-02-01

    A method is presented for forming slugs or cartridges of sample material to be proeessed in a neutronic reactor. Aceording to this invention, the sample material is originally in the fcrm of powder. The powder is placed within a tube formed of a metallic foil. The material encased in the foil is then placed in a die and compressed under sufficient pressure to form a rigid cartridge. The cartridge is then sealed in a metallic can. As a result of this process, crumbling of the compact during handling is eliminated and it is not necessary to clean ana relubricate the die after compression of each cartridge. ~ A method is presented for producing small spherical shot-type pellets from ceramic or refractory materials. According to this process the material to be pelletized is first formed into a powder. The powdered material is then suspended in a liquid carrier or vehicle. Small drops of the suspension, produced by a capillary-drop apparatus, are deposited on the surfacc of a liquid repellent powder, which causes the drops to assume a spherical shape. The liquid is then evaporated from the spherical pellets and tbe pellets are collected and fired to produce the finished product.

  15. Optical polarizing neutron devices designed for pulsed neutron sources

    SciTech Connect (OSTI)

    Takeda, M.; Kurahashi, K.; Endoh, Y.; Itoh, S.

    1997-09-01

    We have designed two polarizing neutron devices for pulsed cold neutrons. The devices have been tested at the pulsed neutron source at the Booster Synchrotron Utilization Facility of the National Laboratory for High Energy Physics. These two devices proved to have a practical use for experiments to investigate condensed matter physics using pulsed cold polarized neutrons.

  16. Twenty years of diffraction at the Tevatron

    SciTech Connect (OSTI)

    Goulianos, K.; /Rockefeller U.

    2005-10-01

    Results on diffractive particle interactions from the Fermilab Tevatron {bar p}p collider are placed in perspective through a QCD inspired phenomenological approach, which exploits scaling and factorization properties observed in data. The results discussed are those obtained by the CDF Collaboration from a comprehensive set of single, double, and multigap soft and hard diffraction processes studied during the twenty year period since 1985, when the CDF diffractive program was proposed and the first Blois Workshop was held.

  17. Diffraction gratings used as identifying markers

    DOE Patents [OSTI]

    Deason, V.A.; Ward, M.B.

    1991-03-26

    A finely detailed diffraction grating is applied to an object as an identifier or tag which is unambiguous, difficult to duplicate, or remove and transfer to another item, and can be read and compared with prior readings with relative ease. The exact pattern of the diffraction grating is mapped by diffraction moire techniques and recorded for comparison with future readings of the same grating. 7 figures.

  18. Large aperture diffractive space telescope

    DOE Patents [OSTI]

    Hyde, Roderick A.

    2001-01-01

    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.

  19. Fabrication and characterization of hexagonal boron nitride powder by spray drying and calcining-nitriding technology

    SciTech Connect (OSTI)

    Shi Xiaoliang Wang Sheng; Yang Hua; Duan Xinglong; Dong Xuebin

    2008-09-15

    Hexagonal boron nitride (hBN) powder was fabricated prepared by the spray drying and calcining-nitriding technology. The effects of nitrided temperature on the phases, morphology and particle size distribution of hBN powder, were investigated. The synthesized powders were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), Fourier transformed infrared spectrum, ultraviolet-visible (UV-vis) spectrum and photoluminescence (PL) spectrum. UV-vis spectrum revealed that the product had one obvious band gap (4.7 eV) and PL spectrum showed that it had a visible emission at 457 nm ({lambda}{sub ex}=230 nm). FESEM image indicated that the particle size of the synthesized hBN was mainly in the range of 0.5-1.5 {mu}m in diameter, and 50-150 nm in thickness. The high-energy ball-milling process following 900 deg. C calcining process was very helpful to obtain fully crystallized hBN at lower temperature. - Graphical abstract: hBN powder was fabricated prepared by spray drying and calcining-nitriding technology. The results indicated that spray drying and calcining-nitriding technology assisted with high-energy ball-milling process following calcined process was a hopeful way to manufacture hBN powder with high crystallinity in industrial scale.

  20. Broadband diffractive lens or imaging element

    DOE Patents [OSTI]

    Ceglio, Natale M. (Livermore, CA); Hawryluk, Andrew M. (Modesto, CA); London, Richard A. (Oakland, CA); Seppala, Lynn G. (Livermore, CA)

    1993-01-01

    A broadband diffractive lens or imaging element produces a sharp focus and/or a high resolution image with broad bandwidth illuminating radiation. The diffractive lens is sectored or segmented into regions, each of which focuses or images a distinct narrowband of radiation but all of which have a common focal length. Alternatively, a serial stack of minus filters, each with a diffraction pattern which focuses or images a distinct narrowband of radiation but all of which have a common focal length, is used. The two approaches can be combined. Multifocal broadband diffractive elements can also be formed. Thin film embodiments are described.

  1. Broadband diffractive lens or imaging element

    DOE Patents [OSTI]

    Ceglio, N.M.; Hawryluk, A.M.; London, R.A.; Seppala, L.G.

    1993-10-26

    A broadband diffractive lens or imaging element produces a sharp focus and/or a high resolution image with broad bandwidth illuminating radiation. The diffractive lens is sectored or segmented into regions, each of which focuses or images a distinct narrowband of radiation but all of which have a common focal length. Alternatively, a serial stack of minus filters, each with a diffraction pattern which focuses or images a distinct narrowband of radiation but all of which have a common focal length, is used. The two approaches can be combined. Multifocal broadband diffractive elements can also be formed. Thin film embodiments are described. 21 figures.

  2. Broadband diffractive lens or imaging element

    DOE Patents [OSTI]

    Ceglio, Natale M. (Livermore, CA); Hawryluk, Andrew M. (Modesto, CA); London, Richard A. (Oakland, CA); Seppala, Lynn G. (Livermore, CA)

    1991-01-01

    A broadband diffractive lens or imaging element produces a sharp focus and/or a high resolution image with broad bandwidth illuminating radiation. The diffractive lens is sectored or segmented into regions, each of which focuses or images a distinct narrowband of radiation but all of which have a common focal length. Alternatively, a serial stack of minus filters, each with a diffraction pattern which focuses or images a distinct narrowband of radiation but all of which have a common focal length, is used. The two approaches can be combined. Multifocal broadband diffractive elements can also be formed.

  3. Effect of Cu addition on the martensitic transformation of powder metallurgy processed Ti–Ni alloys

    SciTech Connect (OSTI)

    Kim, Yeon-wook; Choi, Eunsoo

    2014-10-15

    Highlights: • M{sub s} of Ti{sub 50}Ni{sub 50} powders is 22 °C, while M{sub s} of SPS-sintered porous bulk increases up to 50 °C. • M{sub s} of Ti{sub 50}Ni{sub 40}Cu{sub 20} porous bulk is only 2 °C higher than that of the powders. • Recovered stain of porous TiNi and TiNiCu alloy is more than 1.5%. - Abstract: Ti{sub 50}Ni{sub 50} and Ti{sub 50}Ni{sub 30}Cu{sub 20} powders were prepared by gas atomization and their transformation behaviors were examined by means of differential scanning calorimetry and X-ray diffraction. One-step B2–B19’ transformation occurred in Ti{sub 50}Ni{sub 50} powders, while Ti{sub 50}Ni{sub 30}Cu{sub 20} powders showed B2–B19 transformation behavior. Porous bulks with 24% porosity were fabricated by spark plasma sintering. The martensitic transformation start temperature (50 °C) of Ti{sub 50}Ni{sub 50} porous bulk is much higher than that (22 °C) of the as-solidified powders. However, the martensitic transformation start temperature (35 °C) of Ti{sub 50}Ni{sub 30}Cu{sub 20} porous bulk is almost the same as that (33 °C) of the powders. When the specimens were compressed to the strain of 8% and then unloaded, the residual strains of Ti{sub 50}Ni{sub 50} and Ti{sub 50}Ni{sub 30}Cu{sub 20} alloy bulks were 3.95 and 3.7%, respectively. However, these residual strains were recovered up to 1.7% after heating by the shape memory phenomenon.

  4. Neutron and Nuclear Science News

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    News Recent news and events related to neutron and nuclear science at LANSCE. Neutron and Nuclear Science News Nuclear and Materials Science Research at LANSCE Nuclear science observations and opportunities at the Los Alamos Neutron Science Center Links Neutron and Nuclear Science News Media Links Profiles Events at LANSCE LAPIS (LANSCE Proposal Intake System

  5. Neutron and Nuclear Science Publications

    U.S. Department of Energy (DOE) all 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 Publications ICE House and ICE II Publications (n,z) Publications Neutron Radiography Publications SPIDER Publications Target 2 Publications TPC Publications Links Publications/Media Neutron and Nuclear Science News Profiles Events at LANSCE LANL Research Libary

  6. X-Ray Diffraction > Analytical Resources > Research > The Energy...

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    Analytical Resources In This Section Differential Electrochemical Mass Spectroscopy (DEMS) Electron Microscopy X-Ray Diffraction X-Ray Diffraction...

  7. Low Temperature and Neutron Physics Studies: Final Progress Report, March 1, 1986--May 31, 1987

    DOE R&D Accomplishments [OSTI]

    Shull, C.G.

    1989-07-27

    A search for a novel coupling interaction between the Pendelloesung periodicity which is formed in a diffracting crystal and the Larmor precession of neutrons in a magnetic field has been carried out. This interaction is expected to exhibit a resonant behavior when the two spatial periodicities become matched upon scanning the magnetic field being applied to the crystal. Observations on a diffracting, perfect crystal of silicon with neutrons of wavelength 1 Angstrom show the expected resonant action but some discrepancy between the observed magnitude of the resonance effects remains for interpretation.

  8. Powder-lubricated piston ring development

    SciTech Connect (OSTI)

    Heshmat, H.

    1991-06-01

    The overall objective of this program was to demonstrate the feasibility of a new particulate lubrication concept for reducing piston ring/cylinder liner wear in coal-water slurry-fueled diesels by replacing the present oil-lubricated system with powder lubrication that would utilize coal ash, either alone or in combination with another powder. The feasibility of this particular lubrication concept for reducing ring/liner wear was demonstrated in a series of experiments utilizing redesigned and properly selected components. Wear performance for suitable ring/liner materials lubricated with a powder that incorporates the abrasive ash particles was evaluated in terms of load capacity, friction, and rate of wear for the best combination of ring design, ring and liner materials, and powder constituents. In addition, the use of a powder-lubricated system in the upper portion of the cylinder isolated the particulates from the lower portions of the engine, thus further reducing engine wear. (VC)

  9. Wet powder seal for gas containment

    DOE Patents [OSTI]

    Stang, L.G.

    1979-08-29

    A gas seal is formed by a compact layer of an insoluble powder and liquid filling the fine interstices of that layer. The smaller the particle size of the selected powder, such as sand or talc, the finer will be the interstices or capillary spaces in the layer and the greater will be the resulting sealing capacity, i.e., the gas pressure differential which the wet powder layer can withstand. Such wet powder seal is useful in constructing underground gas reservoirs or storage cavities for nuclear wastes as well as stopping leaks in gas mains buried under ground or situated under water. The sealing capacity of the wet powder seal can be augmented by the hydrostatic head of a liquid body established over the seal.

  10. Wet powder seal for gas containment

    DOE Patents [OSTI]

    Stang, Louis G.

    1982-01-01

    A gas seal is formed by a compact layer of an insoluble powder and liquid filling the fine interstices of that layer. The smaller the particle size of the selected powder, such as sand or talc, the finer will be the interstices or capillary spaces in the layer and the greater will be the resulting sealing capacity, i.e., the gas pressure differential which the wet powder layer can withstand. Such wet powder seal is useful in constructing underground gas reservoirs or storage cavities for nuclear wastes as well as stopping leaks in gas mains buried under ground or situated under water. The sealing capacity of the wet powder seal can be augmented by the hydrostatic head of a liquid body established over the seal.

  11. Switchable radioactive neutron source device

    DOE Patents [OSTI]

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

    1987-11-06

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

  12. Neutron scattering studies of premartensitic phenomena

    SciTech Connect (OSTI)

    Shapiro, S.M.

    1989-01-01

    Elastic neutron diffraction and inelastic neutron scattering are ideal techniques for studying premartensitic behavior in metallic alloys. By necessity, real, bulk samples are probed replete with their intrinsic defects. Also, because of the properties of the neutron it is straightforward to probe the behavior of the phonon modes away from the zone center which is probed in the normal ultrasonic techniques. A wide variety of alloys exhibiting martensitic transformations have been studied. It will be shown that most systems undergoing diffusionless transformations exhibit premartensitic behavior in that precursor effects are seen at temperatures well above the martensitic transformation temperature, T{sub M}. This behavior manifests itself in an anomalous temperature dependence of the energy of a particular phonon mode as the temperature approaches T{sub M}. The wavevector of this mode is frequently away from the zone center (i.e., q {ne} O). This softening is nearly always accompanied by elastic diffuse scattering at the same wavevector. Particular examples to be discussed are the alkali metals, {omega}-phase materials and Ni-based alloys. 34 refs., 9 figs.

  13. Diffraction from HERA to the LHC

    SciTech Connect (OSTI)

    Newman, Paul

    2011-07-15

    Following a 15 year programme of intensive research into diffractive electron-proton scattering at HERA, it is important to transfer the knowledge and experience gained into the LHC programme. This contribution raises some current issues in diffraction at the LHC and suggests ways in which they might be addressed using HERA results.

  14. Hard diffractive production of vector mesons

    SciTech Connect (OSTI)

    Kirschner, R.

    2005-06-14

    The large Q2 behaviour of diffractive electroproduction and the large t behaviour of diffractive photoproduction are considered relying on models of the meson and real photon light-cone wave functions. The large size quark-antiquark dipole contribution to the impact factors of all helicity configurations are discussed.

  15. Experimental developments to obtain real-time x-ray diffraction measurements in plate impact experiments

    SciTech Connect (OSTI)

    Gupta, Y.M.; Zimmerman, K.A.; Rigg, P.A.; Zaretsky, E.B.; Savage, D.M.; Bellamy, P.M.

    1999-10-01

    An experimental facility was developed to obtain real-time, quantitative, x-ray diffraction data in laboratory plate impact experiments. A powder gun, to generate plane wave loading in samples, was designed and built specifically to permit flash x-ray diffraction measurements in shock-compression experiments. Spatial resolution and quality of the diffracted signals were improved significantly over past attempts through partial collimation of the incident beam and the use of two-dimensional detectors to record data from shocked crystals. The experimental configuration and synchronization issues are discussed, and relevant details of the x-ray system and the powder gun are described. Representative results are presented from experiments designed to determine unit cell compression in shock-compressed LiF single crystals subjected to both elastic and elastic-plastic deformation, respectively. The developments described here are expected to be useful for examining lattice deformation and structural changes in shock wave compression studies. {copyright} {ital 1999 American Institute of Physics.}

  16. UNITED STATES ATOMIC ENERGY COMMISSION OAK RIDGE TENNESSEE THE...

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    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 ...

  17. Search for: All records | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    ... c and the unit-cell volume V decrease linearly with increasing Cosup 2+ concentration. ... by neutron powder diffraction using group theory analysis as a preliminary tool. ...

  18. Shifting scintillator neutron detector

    DOE Patents [OSTI]

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

    2014-03-04

    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.

  19. Cylindrical neutron generator

    SciTech Connect (OSTI)

    Leung, Ka-Ngo

    2009-12-29

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  20. Cylindrical neutron generator

    DOE Patents [OSTI]

    Leung, Ka-Ngo

    2008-04-22

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  1. Cylindrical neutron generator

    DOE Patents [OSTI]

    Leung, Ka-Ngo

    2005-06-14

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  2. Neutron resonance averaging

    SciTech Connect (OSTI)

    Chrien, R.E.

    1986-10-01

    The principles of resonance averaging as applied to neutron capture reactions are described. Several illustrations of resonance averaging to problems of nuclear structure and the distribution of radiative strength in nuclei are provided. 30 refs., 12 figs.

  3. The National Nuclear Security Administration's Neutron Generator...

    Energy.gov (indexed) [DOE]

    National Nuclear Security Administration's Neutron Generator Activities OAS-L-14-11 August ... Security Administration's Neutron Generator Activities" BACKGROUND Neutron ...

  4. NEUTRON FLUX INTENSITY DETECTION

    DOE Patents [OSTI]

    Russell, J.T.

    1964-04-21

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

  5. MAGNETIC NEUTRON SCATTERING

    SciTech Connect (OSTI)

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

    2004-07-30

    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

  6. NanoComposite Stainless Steel Powder Technologies (Technical...

    Office of Scientific and Technical Information (OSTI)

    NanoComposite Stainless Steel Powder Technologies Citation Details In-Document Search Title: NanoComposite Stainless Steel Powder Technologies You are accessing a document from ...

  7. Solid State Processing of New Low Cost Titanium Powders Enabling...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Powders Enabling Affordable Automotive Components Solid State Processing of New Low Cost Titanium Powders Enabling Affordable Automotive Components Presentation given at ...

  8. Alternative Metal Oxide Supports for Cathode Catalyst Powder...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    ... Pt 2-D connected network onto individual graphitic carbon nano- powders June 8, 2015 Challenges in Coating Carbon Nano-powders * It is challenging to flow the graphitic ...

  9. Water Outgassing from PBX-9502 powder by isoconversional thermal...

    Office of Scientific and Technical Information (OSTI)

    Water Outgassing from PBX-9502 powder by isoconversional thermal analysis Citation Details In-Document Search Title: Water Outgassing from PBX-9502 powder by isoconversional ...

  10. Fundamental neutron physics at LANSCE

    SciTech Connect (OSTI)

    Greene, G.

    1995-10-01

    Modern neutron sources and science share a common origin in mid-20th-century scientific investigations concerned with the study of the fundamental interactions between elementary particles. Since the time of that common origin, neutron science and the study of elementary particles have evolved into quite disparate disciplines. The neutron became recognized as a powerful tool for studying condensed matter with modern neutron sources being primarily used (and justified) as tools for neutron scattering and materials science research. The study of elementary particles has, of course, led to the development of rather different tools and is now dominated by activities performed at extremely high energies. Notwithstanding this trend, the study of fundamental interactions using neutrons has continued and remains a vigorous activity at many contemporary neutron sources. This research, like neutron scattering research, has benefited enormously by the development of modern high-flux neutron facilities. Future sources, particularly high-power spallation sources, offer exciting possibilities for continuing this research.

  11. MCViNE- An object oriented Monte Carlo neutron ray tracing simulation package

    DOE PAGES-Beta [OSTI]

    Lin, J. Y. Y.; Smith, Hillary L.; Granroth, Garrett E.; Abernathy, Douglas L.; Lumsden, Mark D.; Winn, Barry L.; Aczel, Adam A.; Aivazis, Michael; Fultz, Brent

    2015-11-28

    MCViNE (Monte-Carlo VIrtual Neutron Experiment) is an open-source Monte Carlo (MC) neutron ray-tracing software for performing computer modeling and simulations that mirror real neutron scattering experiments. We exploited the close similarity between how instrument components are designed and operated and how such components can be modeled in software. For example we used object oriented programming concepts for representing neutron scatterers and detector systems, and recursive algorithms for implementing multiple scattering. Combining these features together in MCViNE allows one to handle sophisticated neutron scattering problems in modern instruments, including, for example, neutron detection by complex detector systems, and single and multiplemore » scattering events in a variety of samples and sample environments. In addition, MCViNE can use simulation components from linear-chain-based MC ray tracing packages which facilitates porting instrument models from those codes. Furthermore it allows for components written solely in Python, which expedites prototyping of new components. These developments have enabled detailed simulations of neutron scattering experiments, with non-trivial samples, for time-of-flight inelastic instruments at the Spallation Neutron Source. Examples of such simulations for powder and single-crystal samples with various scattering kernels, including kernels for phonon and magnon scattering, are presented. As a result, with simulations that closely reproduce experimental results, scattering mechanisms can be turned on and off to determine how they contribute to the measured scattering intensities, improving our understanding of the underlying physics.« less

  12. MCViNE- An object oriented Monte Carlo neutron ray tracing simulation package

    SciTech Connect (OSTI)

    Lin, J. Y. Y.; Smith, Hillary L.; Granroth, Garrett E.; Abernathy, Douglas L.; Lumsden, Mark D.; Winn, Barry L.; Aczel, Adam A.; Aivazis, Michael; Fultz, Brent

    2015-11-28

    MCViNE (Monte-Carlo VIrtual Neutron Experiment) is an open-source Monte Carlo (MC) neutron ray-tracing software for performing computer modeling and simulations that mirror real neutron scattering experiments. We exploited the close similarity between how instrument components are designed and operated and how such components can be modeled in software. For example we used object oriented programming concepts for representing neutron scatterers and detector systems, and recursive algorithms for implementing multiple scattering. Combining these features together in MCViNE allows one to handle sophisticated neutron scattering problems in modern instruments, including, for example, neutron detection by complex detector systems, and single and multiple scattering events in a variety of samples and sample environments. In addition, MCViNE can use simulation components from linear-chain-based MC ray tracing packages which facilitates porting instrument models from those codes. Furthermore it allows for components written solely in Python, which expedites prototyping of new components. These developments have enabled detailed simulations of neutron scattering experiments, with non-trivial samples, for time-of-flight inelastic instruments at the Spallation Neutron Source. Examples of such simulations for powder and single-crystal samples with various scattering kernels, including kernels for phonon and magnon scattering, are presented. As a result, with simulations that closely reproduce experimental results, scattering mechanisms can be turned on and off to determine how they contribute to the measured scattering intensities, improving our understanding of the underlying physics.

  13. New diffractive results from the Tevatron

    SciTech Connect (OSTI)

    Gallinaro, Michele; /Rockefeller U.

    2005-05-01

    Experimental results in diffractive processes are summarized and a few notable characteristics described in terms of Quantum Chromodynamics. Exclusive dijet production is used to establish a benchmark for future experiments in the quest for diffractive Higgs production at the Large Hadron Collider. Using new data from the Tevatron and dedicated diffractive triggers, no excess over a smooth falling distribution for exclusive dijet events could be found. Stringent upper limits on the exclusive dijet production cross section are presented. The quark/gluon composition of dijet final states is used to provide additional hints on exclusive dijet production.

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

    SciTech Connect (OSTI)

    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)

    2013-11-15

    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.

  15. Category:Neutron Log | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    Looking for the 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...

  16. Neutron Detection Using an Embedded Sol-Gel Neutron Absorber...

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    Date Patent 5,973,328 Patent 5,973,328 Neutron detector using sol-gel absorber An neutron detector composed of fissionable material having ions of lithium, uranium, thorium, ...

  17. Laminated composite of magnetic alloy powder and ceramic powder and process for making same

    DOE Patents [OSTI]

    Moorhead, A.J.; Kim, H.

    1999-08-10

    A laminated composite structure of alternating metal powder layers, and layers formed of an inorganic bonding media powder, and a method for manufacturing same are disclosed. The method includes the steps of assembling in a cavity alternating layers of a metal powder and an inorganic bonding media of a ceramic, glass, and glass-ceramic. Heat, with or without pressure, is applied to the alternating layers until the particles of the metal powder are sintered together and bonded into the laminated composite structure by the layers of sintered inorganic bonding media to form a strong composite structure. The method finds particular application in the manufacture of high performance magnets wherein the metal powder is a magnetic alloy powder. 9 figs.

  18. Laminated composite of magnetic alloy powder and ceramic powder and process for making same

    DOE Patents [OSTI]

    Moorhead, Arthur J.; Kim, Hyoun-Ee

    1999-01-01

    A laminated composite structure of alternating metal powder layers, and layers formed of an inorganic bonding media powder, and a method for manufacturing same are discosed. The method includes the steps of assembling in a cavity alternating layers of a metal powder and an inorganic bonding media of a ceramic, glass, and glass-ceramic. Heat, with or without pressure, is applied to the alternating layers until the particles of the metal powder are sintered together and bonded into the laminated composite structure by the layers of sintered inorganic bonding media to form a strong composite structure. The method finds particular application in the manufacture of high performance magnets wherein the metal powder is a magnetic alloy powder.

  19. Updated flux information for neutron scattering and irradiation facilities at the BNL High Flux Beam Reactor

    SciTech Connect (OSTI)

    Holden, N.E.; Hu, J.P.; Reciniello, R.N.; Sengupta, S.; Greenwood, L.R.; Farrell, K.

    1997-08-01

    The HFBR is a heavy water, D{sub 2}O, cooled and moderated reactor with twenty-eight fuel elements containing a maximum of 9.8 kilograms of {sup 235}U. While most reactors attempt to minimize the escape of neutrons from the core, the HFBR`s D{sub 2}O design allows the thermal neutron flux to peak in the reflector region and maximizes the number of thermal neutrons available to nine horizontal external beams, H-1 to H-9, used for neutron scattering and capture reactions, supporting physics, chemistry and biology experiments. All horizontal beam tubes were built tangential to the direction of the emerging neutrons, except for the H-2 beam tube, which looks directly at the core and has been used for neutron cross section measurements utilizing fast neutrons and for the TRISTAN fission product studies. In recent years, there have been some beam modifications and new instrumentation introduced at the HFBR. A high resolution neutron powder diffractometer instrument is now operating with a resolution of 5 {times} 10{sup {minus}4} at horizontal beam line H-1. To study scattering from liquid surfaces, a neutron reflection spectrometer was introduced on the CNF beam line at H-9. In the past year, a fourth beam line has been added to the CNF line at H-9. The existing beam plug at the H-6 beam line has recently been removed and a new plug, which will feature super mirrored surfaces, is now being installed. Last year, the vertical beam thimble, V-13, a fixed port filled with thirty year old samples used for HFBR material surveillance studies was replaced by a new thimble and charging station at the core edge creating an irradiation facility to substitute for the original V-13. A neutron dosimetry program has begun to measure and calculate the energy dependent neutron and gamma ray flux densities and/or dose rates at horizontal beam lines and vertical irradiation thimbles.

  20. Powder Dropper | Princeton Plasma Physics Lab

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    Powder Dropper This device releases micron-sized dust particles at a controlled rate through an aperture in a vibrating crystal. The amount of dust released ranges from a few particles ...

  1. Tension in the LHC diffractive data?

    SciTech Connect (OSTI)

    Gotsman, Errol

    2015-04-10

    I discuss the LHC diffractive data, and compare it to predicted energy behaviour of various models. I suggest that the so called 'tension' between the experimental results, maybe due to the different Monte Carlo programs used.

  2. Critical Experiments that Simulated Damp MOX Powders - Do They Meet the Need?

    SciTech Connect (OSTI)

    J. Blair Briggs; Dr. Ali Nouri; Dr. Claes Nordborg

    2005-09-01

    The OECD Nuclear Energy Agency (NEA) Working Party on Nuclear Criticality Safety (WPNCS) identified the MOX fuel manufacturing process as an area in which there is a need for additional integral benchmark data. The specific need focused on damp MOX powders. The WPNCS was ultimately asked by the NEA Nuclear Science Committee (NSC) to provide the framework for the selection and performance of new experiments that fill the identified need. A set of criteria was established to enable uniform comparison of experimental proposals with generic MOX application data. Criteria were established for five general characteristics: (1) neutronic parameters, (2) type of experiments, (3) financial aspects, (4) schedule, and (5) other considerations. Proposals were judged most importantly on their ability to match the neutronic parameters of predetermined MOX applications. The neutronic parameters that formed the basis for comparison included core average values (not local values) for flux, fission and capture rate; detailed balance data (fission and capture) for the main isotopes (Actinides, H and O); sensitivity coefficients to important nuclear reactions (fission, capture, elastic and inelastic scatter, nu-bar, mu-bar) for all uranium and plutonium isotopes, hydrogen, and oxygen; sensitivity profiles to the main nuclear reactions for uranium and plutonium isotopes; energy of average lethargy causing fission; and the average fission group energy. The focus of this paper is on the definition of the need; the neutronics criteria established to assess which, if any, of three proposed MOX experimental programs best meet the need; and the actual assessment of the proposed experimental programs.

  3. Hybrid superconducting neutron detectors

    SciTech Connect (OSTI)

    Merlo, V.; Lucci, M.; Ottaviani, I.; Salvato, M.; Cirillo, M.; Scherillo, A.; Celentano, G.; Pietropaolo, A.

    2015-03-16

    A neutron detection concept is presented that is based on superconductive niobium (Nb) strips coated by a boron (B) layer. The working principle of the detector relies on the nuclear reaction, {sup 10}B + n → α + {sup 7}Li, with α and Li ions generating a hot spot on the current-biased Nb strip which in turn induces a superconducting-normal state transition. The latter is recognized as a voltage signal which is the evidence of the incident neutron. The above described detection principle has been experimentally assessed and verified by irradiating the samples with a pulsed neutron beam at the ISIS spallation neutron source (UK). It is found that the boron coated superconducting strips, kept at a temperature T = 8 K and current-biased below the critical current I{sub c}, are driven into the normal state upon thermal neutron irradiation. As a result of the transition, voltage pulses in excess of 40 mV are measured while the bias current can be properly modulated to bring the strip back to the superconducting state, thus resetting the detector. Measurements on the counting rate of the device are presented and the basic physical features of the detector are discussed.

  4. Portable Neutron Sensors for Emergency Response Operations

    SciTech Connect (OSTI)

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

    2012-06-22

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

  5. Synthesis and processing of monosized oxide powders

    DOE Patents [OSTI]

    Barringer, Eric A.; Fegley, Jr., M. Bruce; Bowen, H. Kent

    1985-01-01

    Uniform-size, high-purity, spherical oxide powders are formed by hydrolysis of alkoxide precursors in dilute alcoholic solutions. Under controlled conditions (concentrations of 0.03 to 0.2 M alkoxide and 0.2 to 1.5 M water, for example) oxide particles on the order of about 0.05 to 0.7 micron can be produced. Methods of doping such powders and forming sinterable compacts are also disclosed.

  6. Synthesis and processing of monosized oxide powders

    DOE Patents [OSTI]

    Barringer, E.A.; Fegley, M.B. Jr.; Bowen, H.K.

    1985-09-24

    Uniform-size, high-purity, spherical oxide powders are formed by hydrolysis of alkoxide precursors in dilute alcoholic solutions. Under controlled conditions (concentrations of 0.03 to 0.2 M alkoxide and 0.2 to 1.5 M water, for example) oxide particles on the order of about 0.05 to 0.7 microns can be produced. Methods of doping such powders and forming sinterable compacts are also disclosed. 6 figs.

  7. Biaxially textured articles formed by powder metallurgy

    DOE Patents [OSTI]

    Goyal, Amit; Williams, Robert K.

    2001-01-01

    A biaxially textured alloy article comprises Ni powder and at least one powder selected from the group consisting of Cr, W, V, Mo, Cu, Al, Ce, YSZ, Y, Rare Earths, (RE), MgO, CeO.sub.2, and Y.sub.2 O.sub.3 ; compacted and heat treated, then rapidly recrystallized to produce a biaxial texture on the article. In some embodiments the alloy article further comprises electromagnetic or electro-optical devices and possesses superconducting properties.

  8. Active diffraction gratings: Development and tests

    SciTech Connect (OSTI)

    Bonora, S.; Frassetto, F.; Poletto, L. [Institute of Photonics and Nanotechnologies, National Council for Research of Italy, via Trasea, 7, Padova 35131 (Italy); Zanchetta, E.; Della Giustina, G.; Brusatin, G. [Industrial Engineering Department, University of Padova, Via Marzolo 9, 35131 Padova (Italy)

    2012-12-15

    We present the realization and characterization of an active spherical diffraction grating with variable radius of curvature to be used in grazing-incidence monochromators. The device consists of a bimorph deformable mirror on the top of which a diffraction grating with laminar profile is realized by UV lithography. The experimental results show that the active grating can optimize the beam focalization of visible wavelengths through its rotation and focus accommodation.

  9. Neutron beam characterization at the Neutron Radiography Reactor (NRAD)

    SciTech Connect (OSTI)

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

    1990-01-01

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

  10. Synthesis of nanoscale magnesium diboride powder

    SciTech Connect (OSTI)

    Finnemore, D. K.; Marzik, J. V.

    2015-12-18

    A procedure has been developed for the preparation of small grained magnesium diboride (MgB2) powder by reacting nanometer size boron powder in a magnesium vapor. Plasma synthesized boron powder that had particle sizes ranging from 20 to 300nm was mixed with millimeter size chunks of Mg by rolling stoichiometric amounts of the powders in a sealed cylindrical container under nitrogen gas. This mixture then was placed in a niobium reaction vessel, evacuated, and sealed by e-beam welding. The vessel was typically heated to approximately 830°C for several hours. The resulting MgB2 particles have a grain size in the 200 nm to 800 nm range. Agglomerates of loosely bound particles could be broken up by light grinding in a mortar and pestle. At 830°C, many particles are composed of several grains grown together so that the average particle size is about twice the average grain size. Furthermore, experiments were conducted primarily with undoped boron powder, but carbon-doped boron powder showed very similar results.

  11. Synthesis of nanoscale magnesium diboride powder

    DOE PAGES-Beta [OSTI]

    Finnemore, D. K.; Marzik, J. V.

    2015-12-18

    A procedure has been developed for the preparation of small grained magnesium diboride (MgB2) powder by reacting nanometer size boron powder in a magnesium vapor. Plasma synthesized boron powder that had particle sizes ranging from 20 to 300nm was mixed with millimeter size chunks of Mg by rolling stoichiometric amounts of the powders in a sealed cylindrical container under nitrogen gas. This mixture then was placed in a niobium reaction vessel, evacuated, and sealed by e-beam welding. The vessel was typically heated to approximately 830°C for several hours. The resulting MgB2 particles have a grain size in the 200 nmmore » to 800 nm range. Agglomerates of loosely bound particles could be broken up by light grinding in a mortar and pestle. At 830°C, many particles are composed of several grains grown together so that the average particle size is about twice the average grain size. Furthermore, experiments were conducted primarily with undoped boron powder, but carbon-doped boron powder showed very similar results.« less

  12. The basics of powder lubrication in high-temperature powder-lubricated dampers

    SciTech Connect (OSTI)

    Heshmat, H.; Walton, J.F. )

    1993-04-01

    The objective of this investigation is to develop a novel powder-lubricated rotor bearing system damper concept for use in high-temperature, high-speed rotating machinery such as advanced aircraft gas turbine engines. The approach discussed herein consists of replacing a conventional oil lubrication or frictional damper system with a powder lubrication system that uses the process particulates or externally fed powder lubricant. Unlike previous work in this field, this approach is based on the postulate of the quasi-hydrodynamic nature of powder lubrication. This postulate is deduced from past observation and present verification that there are a number of basic features of powder flow in narrow interfaces that have the characteristic behavior of fluid film lubrication. In addition to corroborating the basic mechanism of powder lubrication, the conceptual and experimental work performed in this program provides guidelines for selection of the proper geometries, materials, and powders suitable for this tribological process. The present investigation describes the fundamentals of quasi-hydrodynamic powder lubrication and defines the rationale underlying the design of the test facility. The performance and the results of the experimental program present conclusions reached regarding design requirements as well as the formulation of a proper model of quasi-hydrodynamic powder lubrication.

  13. Structural and spectroscopic analyses of europium doped yttrium oxyfluoride powders prepared by combustion synthesis

    SciTech Connect (OSTI)

    Rakov, Nikifor; Guimares, R. B.; Maciel, Glauco S.; Lozano B, W.

    2013-07-28

    A facile widely spread technique employed to produce low-cost high-yield oxide powders, combustion synthesis, was used to prepare yttrium oxyfluoride crystalline ceramic powders. The structure of the powders was analyzed by X-ray powder diffraction and Rietveld refinement. Samples heat treated at 700 C had a predominance of vernier orthorhombic Y{sub 6}O{sub 5}F{sub 8} phase, while samples heat treated at 800 C crystallized in stoichiometric rhombohedral YOF phase. The samples were doped with luminescent europium trivalent ions (Eu{sup 3+}) in different concentrations (115 wt.%) and Judd-Ofelt theory was used to probe the distortion from the inversion symmetry of the local crystal field and the degree of covalency between the rare-earth ion and the surrounding ligands. The luminescence lifetime was measured and the luminescence quantum efficiency (LQE) was estimated. We observed that Eu{sup 3+}:Y{sub 6}O{sub 5}F{sub 8} samples presented higher LQE in spite of the larger local crystal field anisotropy found for Eu{sup 3+}:YOF samples.

  14. Neutron Log | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    Dictionary.png Neutron Log: The neutron log responds primarily to the amount of hydrogen in the formation which is contained in oil, natural gas, and water. The amount of...

  15. Spherical neutron generator

    DOE Patents [OSTI]

    Leung, Ka-Ngo

    2006-11-21

    A spherical neutron generator is formed with a small spherical target and a spherical shell RF-driven plasma ion source surrounding the target. A deuterium (or deuterium and tritium) ion plasma is produced by RF excitation in the plasma ion source using an RF antenna. The plasma generation region is a spherical shell between an outer chamber and an inner extraction electrode. A spherical neutron generating target is at the center of the chamber and is biased negatively with respect to the extraction electrode which contains many holes. Ions passing through the holes in the extraction electrode are focused onto the target which produces neutrons by D-D or D-T reactions.

  16. METHOD OF PRODUCING NEUTRONS

    DOE Patents [OSTI]

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

    1964-02-01

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

  17. Personnel electronic neutron dosimeter

    DOE Patents [OSTI]

    Falk, Roger B.; Tyree, William H.

    1984-12-18

    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.

  18. Personnel electronic neutron dosimeter

    DOE Patents [OSTI]

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

    1982-03-03

    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.

  19. Neutronic reactor construction

    DOE Patents [OSTI]

    Huston, Norman E.

    1976-07-06

    1. A neutronic reactor comprising a moderator including horizontal layers formed of horizontal rows of graphite blocks, alternate layers of blocks having the rows extending in one direction, the remaining alternate layers having the rows extending transversely to the said one direction, alternate rows of blocks in one set of alternate layers having longitudinal ducts, the moderator further including slotted graphite tubes positioned in the ducts, the reactor further comprising an aluminum coolant tube positioned within the slotted tube in spaced relation thereto, bodies of thermal-neutron-fissionable material, and jackets enclosing the bodies and being formed of a corrosion-resistant material having a low neutron-capture cross section, the bodies and jackets being positioned within the coolant tube so that the jackets are spaced from the coolant tube.

  20. Ultrafast neutron detector

    DOE Patents [OSTI]

    Wang, Ching L.

    1987-01-01

    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.

  1. Solid phases of spatially nanoconfined oxygen: A neutron scattering study

    SciTech Connect (OSTI)

    Kojda, Danny [Helmholtz-Zentrum Berlin fr Materialien und Energie GmbH, 14109 Berlin (Germany) [Helmholtz-Zentrum Berlin fr Materialien und Energie GmbH, 14109 Berlin (Germany); Freie Universitt Berlin, 14195 Berlin (Germany); Wallacher, Dirk; Hofmann, Tommy, E-mail: tommy.hofmann@helmholtz-berlin.de [Helmholtz-Zentrum Berlin fr Materialien und Energie GmbH, 14109 Berlin (Germany)] [Helmholtz-Zentrum Berlin fr Materialien und Energie GmbH, 14109 Berlin (Germany); Baudoin, Simon; Hansen, Thomas [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France)] [Institut Laue-Langevin, BP 156, 38042 Grenoble Cedex 9 (France); Huber, Patrick [Technische Universitt Hamburg-Harburg, 21073 Hamburg (Germany)] [Technische Universitt Hamburg-Harburg, 21073 Hamburg (Germany)

    2014-01-14

    We present a comprehensive neutron scattering study on solid oxygen spatially confined in 12 nm wide alumina nanochannels. Elastic scattering experiments reveal a structural phase sequence known from bulk oxygen. With decreasing temperature cubic ?-, orthorhombic ?- and monoclinic ?-phases are unambiguously identified in confinement. Weak antiferromagnetic ordering is observed in the confined monoclinic ?-phase. Rocking scans reveal that oxygen nanocrystals inside the tubular channels do not form an isotropic powder. Rather, they exhibit preferred orientations depending on thermal history and the very mechanisms, which guide the structural transitions.

  2. Corrosion resistant neutron absorbing coatings

    DOE Patents [OSTI]

    Choi, Jor-Shan; Farmer, Joseph C.; Lee, Chuck K.; Walker, Jeffrey; Russell, Paige; Kirkwood, Jon; Yang, Nancy; Champagne, Victor

    2012-05-29

    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.

  3. Corrosion resistant neutron absorbing coatings

    DOE Patents [OSTI]

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

    2013-11-12

    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.

  4. Hydration mechanisms of ternary Portland cements containing limestone powder and fly ash

    SciTech Connect (OSTI)

    De Weerdt, K.; Haha, M. Ben; Le Saout, G.; Kjellsen, K.O.; Justnes, H.; Lothenbach, B.

    2011-03-15

    The effect of minor additions of limestone powder on the properties of fly ash blended cements was investigated in this study using isothermal calorimetry, thermogravimetry (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) techniques, and pore solution analysis. The presence of limestone powder led to the formation of hemi- and monocarbonate and to a stabilisation of ettringite compared to the limestone-free cements, where a part of the ettringite converted to monosulphate. Thus, the presence of 5% of limestone led to an increase of the volume of the hydrates, as visible in the increase in chemical shrinkage, and an increase in compressive strength. This effect was amplified for the fly ash/limestone blended cements due to the additional alumina provided by the fly ash reaction.

  5. Innovative Powder Processing of Oxide Dispersion Strengthened ODS Ferritic Stainless Steels

    SciTech Connect (OSTI)

    Rieken, Joel; Anderson, Iver; Kramer, Matthew

    2011-04-01

    An innovative gas atomization reaction synthesis technique was employed as a viable method to dramatically lower the processing cost for precursor oxide dispersion forming ferritic stainless steel powders (i.e., Fe-Cr-(Hf,Ti)-Y). During this rapid solidification process the atomized powders were enveloped by a nano-metric Cr-enriched metastable oxide film. Elevated temperature heat treatment was used to dissociate this metastable oxide phase through oxygen exchange reactions with Y-(Hf,Ti) enriched intermetallic compound precipitates. These solid state reactions resulted in the formation of highly stable nano-metric mixed oxide dispersoids (i.e., Y-Ti-O or Y-Hf-O) throughout the alloy microstructure. Subsequent high temperature (1200 C) heat treatments were used to elucidate the thermal stability of each nano-metric oxide dispersoid phase. Transmission electron microscopy coupled with X-ray diffraction was used to evaluate phase evolution within the alloy microstructure.

  6. A sol-powder coating technique for fabrication of yttria stabilised zirconia

    SciTech Connect (OSTI)

    Wattanasiriwech, Darunee . E-mail: darunee@mfu.ac.th; Wattanasiriwech, Suthee; Stevens, Ron

    2006-08-10

    Yttria stabilised zirconia has been prepared using a simple sol-powder coating technique. The polymeric yttria sol, which was prepared using 1,3 propanediol as a network modifier, was homogeneously mixed with nanocrystalline zirconia powder and it showed a dual function: as a binder which promoted densification and a phase modifier which stabilised zirconia in the tetragonal and cubic phases. Thermal analysis and X-ray diffraction revealed that the polymeric yttria sol which decomposed at low temperature into yttrium oxide could change the m {sup {yields}} t phase transformation behaviour of the zirconia, possibly due to the small particle size and very high surface area of both yttria and zirconia particles allowing rapid alloying. The sintered samples exhibited three crystalline phases: monoclinic, tetragonal and cubic, in which cubic and tetragonal are the major phases. The weight fractions of the individual phases present in the selected specimens were determined using quantitative Rietveld analysis.

  7. GUIDE FOR POLARIZED NEUTRONS

    DOE Patents [OSTI]

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

    1962-12-01

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

  8. Neutron activated switch

    DOE Patents [OSTI]

    Barton, David M.

    1991-01-01

    A switch for reacting quickly to a neutron emission. A rod consisting of fissionable material is located inside a vacuum tight body. An adjustable contact is located coaxially at an adjustable distance from one end of the rod. Electrical leads are connected to the rod and to the adjustable contact. With a vacuum drawn inside the body, a neutron bombardment striking the rod causes it to heat and expand longitudinally until it comes into contact with the adjustable contact. This circuit closing occurs within a period of a few microseconds.

  9. FAST NEUTRONIC REACTOR

    DOE Patents [OSTI]

    Snell, A.H.

    1957-12-01

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

  10. NEUTRONIC REACTOR CONTROL ELEMENT

    DOE Patents [OSTI]

    Newson, H.W.

    1960-09-13

    A novel composite neutronic reactor control element is offered. The element comprises a multiplicity of sections arranged in end-to-end relationship, each of the sections having a markedly different neutron-reactive characteristic. For example, a three-section control element could contain absorber, moderator, and fuel sections. By moving such an element longitudinally through a reactor core, reactivity is decreased by the absorber, increased slightly by the moderator, or increased substantially by the fuel. Thus, control over a wide reactivity range is provided.

  11. Simplified fast neutron dosimeter

    DOE Patents [OSTI]

    Sohrabi, Mehdi

    1979-01-01

    Direct fast-neutron-induced recoil and alpha particle tracks in polycarbonate films may be enlarged for direct visual observation and automated counting procedures employing electrochemical etching techniques. Electrochemical etching is, for example, carried out in a 28% KOH solution at room temperature by applying a 2000 V peak-to-peak voltage at 1 kHz frequency. Such recoil particle amplification can be used for the detection of wide neutron dose ranges from 1 mrad. to 1000 rads. or higher, if desired.

  12. Iowa Powder Atomization Technologies, Inc. | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Iowa Powder Atomization Technologies, Inc. America's Next Top Energy Innovator Challenge 6067 likes Iowa Powder Atomization Technologies, Inc. Ames Laboratory Iowa Powder Atomization Technologies, Inc. (IPAT) aims to become a leading domestic titanium powder producer allowing for a paradigm shift in the cost of titanium powders for metal injection molding (MIM) feedstock. Decreasing this cost will create vast opportunities for aerospace, military, biomedical, and consumer applications. Titanium

  13. Slip casting nano-particle powders for making transparent ceramics

    DOE Patents [OSTI]

    Kuntz, Joshua D.; Soules, Thomas F.; Landingham, Richard Lee; Hollingsworth, Joel P.

    2011-04-12

    A method of making a transparent ceramic including the steps of providing nano-ceramic powders in a processed or unprocessed form, mixing the powders with de-ionized water, the step of mixing the powders with de-ionized water producing a slurry, sonifing the slurry to completely wet the powder and suspend the powder in the de-ionized water, separating very fine particles from the slurry, molding the slurry, and curing the slurry to produce the transparent ceramic.

  14. In-situ neutron scattering studies of magnetic shape memory alloys under stress, temperature, and magnetic fields

    SciTech Connect (OSTI)

    Brown, Donald W; Sisneros, Thomas A; Kabra, Saurabh; Schlagel, Deborah

    2010-01-01

    We have utilized the SMARTS engineering neutron diffractometer to study the crystallographic orientation and phase transformations in the ferromagnetic shape memory alloy Ni 2MnGa under conditions of temperature (200-600K), stress (500MPa), and magnetic field (2T). Neutrons are uniquely suited to probe the crystallographic response of materials to external stimuli because of their high penetration, which allows them to sample the bulk of the material (as opposed to the surface) as well as pass through environmental chambers. A single crystal of Ni{sub 5}MnGa was repeatedly thermally cycled through the Austenitic-Martensitic phase transformation under varying conditions of applied stress, magnetic field or both. In-situ neutron diffraction was used to quantitatively monitor the population of the crystallographic variants in the martensitic phase as a function of the external stimuli during cooling. Neutron diffraction was used to monitor variant selection in the Ferromagnetic Shape Memory Alloy Ni{sub 2}Mn Ga during austenitic to martensitic transformation under varying conditions of externally applied stress and magnetic field. Qualitatively, the results were to be expected in this simple example. The shorter and magnetically soft c-axis of the tetragonal martensitic phase aligned with the compressive stress or magnetic field. However, neutron diffraction proved useful in directly quantifying the selection of the preferred variant by external influence. For instance, by quantifying the variant selection, the neutron diffraction results made apparent that the sample 'remembered' a loading cycle following a 'reset' cycle with no external applied stress. Moreover, the power of in-situ neutron diffraction will become more apparent when applied to more complex, less understood, samples such as polycrystalline samples or composite samples.

  15. NEUTRONIC REACTOR CONTROL ELEMENT

    DOE Patents [OSTI]

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

    1962-04-17

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

  16. Neutronic reactor thermal shield

    DOE Patents [OSTI]

    Wende, Charles W. J.

    1976-06-15

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

  17. NEUTRONIC REACTOR STRUCTURE

    DOE Patents [OSTI]

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

    1961-05-30

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

  18. Neutronic Reactor Structure

    DOE Patents [OSTI]

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

    1961-05-30

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

  19. NEUTRONIC REACTOR SHIELDING

    DOE Patents [OSTI]

    Borst, L.B.

    1961-07-11

    A special hydrogenous concrete shielding for reactors is described. In addition to Portland cement and water, the concrete essentially comprises 30 to 60% by weight barytes aggregate for enhanced attenuation of fast neutrons. The biological shields of AEC's Oak Ridge Graphite Reactor and Materials Testing Reactor are particular embodiments.

  20. Neutron Absorbing Alloys

    DOE Patents [OSTI]

    Mizia, Ronald E.; Shaber, Eric L.; DuPont, John N.; Robino, Charles V.; Williams, David B.

    2004-05-04

    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.

  1. Microarcsecond relative astrometry from the ground with a diffractive...

    Office of Scientific and Technical Information (OSTI)

    ground with a diffractive pupil Citation Details In-Document Search Title: Microarcsecond relative astrometry from the ground with a diffractive pupil Authors: Ammons, S M ; ...

  2. Category:X-Ray Diffraction (XRD) | Open Energy Information

    Open Energy Information (Open El) [EERE & EIA]

    X-Ray Diffraction (XRD) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Geothermalpower.jpg Looking for the X-Ray Diffraction (XRD) page? For detailed information on...

  3. Test of factorization in diffractive deep inelastic scattering...

    Office of Scientific and Technical Information (OSTI)

    Test of factorization in diffractive deep inelastic scattering and photoproduction at HERA Citation Details In-Document Search Title: Test of factorization in diffractive deep ...

  4. Biological Imaging by Soft X-Ray Diffraction Microscopy

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    methods (see previous highlight, "Demonstration of Coherent X-Ray Diffraction Imaging"). Experimental diffraction data used as input to the difference map algorithm....

  5. XFEL diffraction: Developing processing methods to optimize data...

    Office of Scientific and Technical Information (OSTI)

    XFEL diffraction: Developing processing methods to optimize data quality Citation Details In-Document Search Title: XFEL diffraction: Developing processing methods to optimize data...

  6. Solid state neutron detector array

    DOE Patents [OSTI]

    Seidel, J.G.; Ruddy, F.H.; Brandt, C.D.; Dulloo, A.R.; Lott, R.G.; Sirianni, E.; Wilson, R.O.

    1999-08-17

    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. 7 figs.

  7. Solid state neutron detector array

    DOE Patents [OSTI]

    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)

    1999-01-01

    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.

  8. The Brief Lives of Neutrons

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    The Brief Lives of Neutrons 1663 Los Alamos science and technology magazine Latest Issue:July 2016 past issues All Issues » submit The Brief Lives of Neutrons A unique experiment to pin down the neutron's surprisingly elusive half-life July 21, 2016 Most neutrons inside atoms are stable. But get one on its own, and it will disintegrate in about ten minutes. Most neutrons inside atoms are stable. But get one on its own, and it will disintegrate in about ten minutes. Beam and bottle experiments

  9. Dose-equivalent neutron dosimeter

    DOE Patents [OSTI]

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

    1981-01-07

    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.

  10. Chemical Reduction of Nd1.85Ce0.15CuO4??Powders in Supercritical Sodium Ammonia Solutions

    DOE PAGES-Beta [OSTI]

    Dias, Yasmin; Wang, Hui; Zhou, Haiqing; Lin, Feng; Lan, Yucheng

    2015-01-01

    Nd1.85Ce0.15CuO4??powders are chemically reduced in supercritical sodium ammonia solutions from room temperature to 350C. The crystallographic structure of the reduced powders is investigated from Rietveld refinement of X-ray powder diffraction. The atomic positions are maintained constant within experimental errors while temperature factors of all atoms increase significantly after the chemical treatments, especially of Nd/Ce atoms. The ammonothermally reduced Nd1.85Ce0.15CuO4??powders show diamagnetic below 24?K which is contributed to the lower oxygen content and higher temperature factors of atoms in the treated compound. The ammonothermal method paves a new way to reduce oxides in supercritical solutions near room temperature.

  11. Chemical Reduction of Nd 1.85 Ce 0.15 CuO 4− δ Powders in Supercritical Sodium Ammonia Solutions

    DOE PAGES-Beta [OSTI]

    Dias, Yasmin; Wang, Hui; Zhou, Haiqing; Lin, Feng; Lan, Yucheng

    2015-01-01

    Nd 1.85 Ce 0.15 CuO 4− δ powders are chemically reduced in supercritical sodium ammonia solutions from room temperature to 350°C. The crystallographic structure of the reduced powders is investigated from Rietveld refinement of X-ray powder diffraction. The atomic positions are maintained constant within experimental errors while temperature factors of all atoms increase significantly after the chemical treatments, especially of Nd/Ce atoms. The ammonothermally reduced Nd 1.85 Ce 0.15 CuO 4− δ powders show diamagnetic below 24 K which is contributed to the lower oxygen content and higher temperature factors of atoms in the treated compound.more » The ammonothermal method paves a new way to reduce oxides in supercritical solutions near room temperature.« less

  12. Die-target for dynamic powder consolidation

    DOE Patents [OSTI]

    Flinn, John E.; Korth, Gary E.

    1986-01-01

    A die/target is disclosed for consolidation of a powder, especially an atomized rapidly solidified metal powder, to produce monoliths by the dynamic action of a shock wave, especially a shock wave produced by the detonation of an explosive charge. The die/target comprises a rectangular metal block having a square primary surface with four rectangular mold cavities formed therein to receive the powder. The cavities are located away from the geometrical center of the primary surface and are distributed around such center while also being located away from the geometrical diagonals of the primary surface to reduce the action of reflected waves so as to avoid tensile cracking of the monoliths. The primary surface is covered by a powder retention plate which is engaged by a flyer plate to transmit the shock wave to the primary surface and the powder. Spawl plates are adhesively mounted on other surfaces of the block to act as momentum traps so as to reduce reflected waves in the block.

  13. Die-target for dynamic powder consolidation

    DOE Patents [OSTI]

    Flinn, J.E.; Korth, G.E.

    1985-06-27

    A die/target is disclosed for consolidation of a powder, especially an atomized rapidly solidified metal powder, to produce monoliths by the dynamic action of a shock wave, especially a shock wave produced by the detonation of an explosive charge. The die/target comprises a rectangular metal block having a square primary surface with four rectangular mold cavities formed therein to receive the powder. The cavities are located away from the geometrical center of the primary surface and are distributed around such center while also being located away from the geometrical diagonals of the primary surface to reduce the action of reflected waves so as to avoid tensile cracking of the monoliths. The primary surface is covered by a powder retention plate which is engaged by a flyer plate to transmit the shock wave to the primary surface and the powder. Spawl plates are adhesively mounted on other surfaces of the block to act as momentum traps so as to reduce reflected waves in the block. 4 figs.

  14. Dynamic compaction of tungsten carbide powder.

    SciTech Connect (OSTI)

    Gluth, Jeffrey Weston; Hall, Clint Allen; Vogler, Tracy John; Grady, Dennis Edward

    2005-04-01

    The shock compaction behavior of a tungsten carbide powder was investigated using a new experimental design for gas-gun experiments. This design allows the Hugoniot properties to be measured with reasonably good accuracy despite the inherent difficulties involved with distended powders. The experiments also provide the first reshock state for the compacted powder. Experiments were conducted at impact velocities of 245, 500, and 711 m/s. A steady shock wave was observed for some of the sample thicknesses, but the remainder were attenuated due to release from the back of the impactor or the edge of the sample. The shock velocity for the powder was found to be quite low, and the propagating shock waves were seen to be very dispersive. The Hugoniot density for the 711 m/s experiment was close to ambient crystal density for tungsten carbide, indicating nearly complete compaction. When compared with quasi-static compaction results for the same material, the dynamic compaction data is seen to be significantly stiffer for the regime over which they overlap. Based on these initial results, recommendations are made for improving the experimental technique and for future work to improve our understanding of powder compaction.

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

    DOE Patents [OSTI]

    Smither, R.K.

    1982-03-25

    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.

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

    DOE Patents [OSTI]

    Smither, Robert K.

    1984-01-01

    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.

  17. Coated Fiber Neutron Detector Test

    SciTech Connect (OSTI)

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

    2009-10-23

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

  18. Ultra-high density diffraction grating

    DOE Patents [OSTI]

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

    2012-12-11

    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.

  19. Data Exploration Toolkit for serial diffraction experiments

    DOE PAGES-Beta [OSTI]

    Zeldin, Oliver B.; Brewster, Aaron S.; Hattne, Johan; Uervirojnangkoorn, Monarin; Lyubimov, Artem Y.; Zhou, Qiangjun; Zhao, Minglei; Weis, William I.; Sauter, Nicholas K.; Brunger, Axel T.

    2015-01-23

    Ultrafast diffraction at X-ray free-electron lasers (XFELs) has the potential to yield new insights into important biological systems that produce radiation-sensitive crystals. An unavoidable feature of the 'diffraction before destruction' nature of these experiments is that images are obtained from many distinct crystals and/or different regions of the same crystal. Combined with other sources of XFEL shot-to-shot variation, this introduces significant heterogeneity into the diffraction data, complicating processing and interpretation. To enable researchers to get the most from their collected data, a toolkit is presented that provides insights into the quality of, and the variation present in, serial crystallography datamore » sets. These tools operate on the unmerged, partial intensity integration results from many individual crystals, and can be used on two levels: firstly to guide the experimental strategy during data collection, and secondly to help users make informed choices during data processing.« less

  20. Coherent diffractive imaging of single layer microspheres

    SciTech Connect (OSTI)

    Dinh, Khuong Ba Le, Hoang Vu; Van Vuong, Cuong; Hannaford, Peter; Van Dao, Lap; Ong, Adabelle X. P.; Henderson, Clare A.; Smith, Trevor A.

    2015-04-28

    We report the extreme ultraviolet (XUV) coherent diffractive imaging of silica/polymer micro-particle samples illuminated by a table-top high harmonic generation source at the wavelength of 30 nm. We achieve images constructed from diffraction patterns acquired with 13 μm × 13 μm samples comprising a sparse monolayer of spherical silica and polymer micro-particles. Successful reconstructed image of an aperiodic sample using this HHG source will open the path to the realization of a compact soft x-ray microscope to investigate other complex absorbing samples.

  1. Morphology and structural development of reduced anatase-TiO{sub 2} by pure Ti powder upon annealing and nitridation: Synthesis of TiO{sub x} and TiO{sub x}N{sub y} powders

    SciTech Connect (OSTI)

    Bolokang, A.S.; Motaung, D.E.

    2015-02-15

    It is well known that nitriding of titanium is suitable for surface coating of biomaterials and in other applications such as anti-reflective coating, while oxygen-rich titanium oxynitride has been applied in thin film resistors and photocatalysis. Thus in this work anatase was reduced with pure titanium powder during annealing in argon. This was done to avoid any metallic contamination and unwanted residual metal doping. As a result, interesting and different types of particle morphology were synthesized when the pre-milled elemental anatase and titanium powders were mixed. The formation of metastable face centred cubic and monoclinic titanium monoxide was detected by the X-ray diffraction technique. The phases were confirmed by energy dispersive X-ray spectroscopy analysis. Raman analysis revealed weak intensity peaks for samples annealed in argon as compared to those annealed under nitrogen. - Graphical abstract: Display Omitted - Highlights: • Reaction of TiO{sub 2} and Ti induced metastable FCC and monoclinic TiO{sub x}. • Compositions of mixed powder were prepared from the unmilled and pre-milled powders. • Nitridation of TiO{sub x} yielded TiO{sub x}N{sub y} phase. • Mixed morphology was observed on all three powder samples.

  2. Biaxially textured articles formed by powder metallurgy

    DOE Patents [OSTI]

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-10-21

    A strengthened, biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed, compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: Ni, Ag, Ag--Cu, Ag--Pd, Ni--Cu, Ni--V, Ni--Mo, Ni--Al, Ni--Cr--Al, Ni--W--Al, Ni--V--Al, Ni--Mo--Al, Ni--Cu--Al; and at least one fine metal oxide powder; the article having a grain size which is fine and homogeneous; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  3. Atomization methods for forming magnet powders

    DOE Patents [OSTI]

    Sellers, Charles H.; Branagan, Daniel J.; Hyde, Timothy A.

    2000-01-01

    The invention encompasses methods of utilizing atomization, methods for forming magnet powders, methods for forming magnets, and methods for forming bonded magnets. The invention further encompasses methods for simulating atomization conditions. In one aspect, the invention includes an atomization method for forming a magnet powder comprising: a) forming a melt comprising R.sub.2.1 Q.sub.13.9 B.sub.1, Z and X, wherein R is a rare earth element; X is an element selected from the group consisting of carbon, nitrogen, oxygen and mixtures thereof; Q is an element selected from the group consisting of Fe, Co and mixtures thereof; and Z is an element selected from the group consisting of Ti, Zr, Hf and mixtures thereof; b) atomizing the melt to form generally spherical alloy powder granules having an internal structure comprising at least one of a substantially amorphous phase or a substantially nanocrystalline phase; and c) heat treating the alloy powder to increase an energy product of the alloy powder; after the heat treatment, the alloy powder comprising an energy product of at least 10 MGOe. In another aspect, the invention includes a magnet comprising R, Q, B, Z and X, wherein R is a rare earth element; X is an element selected from the group consisting of carbon, nitrogen, oxygen and mixtures thereof; Q is an element selected from the group consisting of Fe, Co and mixtures thereof; and Z is an element selected from the group consisting of Ti, Zr, Hf and mixtures thereof; the magnet comprising an internal structure comprising R.sub.2.1 Q.sub.13.9 B.sub.1.

  4. Desensitizing nano powders to electrostatic discharge ignition

    SciTech Connect (OSTI)

    Steelman, Ryan; Clark, Billy; Pantoya, Michelle L.; Heaps, Ronald J.; Daniels, Michael A.

    2015-08-01

    Electrostatic discharge (ESD) is a main cause for ignition in powder media ranging from grain silos to fireworks. Nanoscale particles are orders of magnitude more ESD ignition sensitive than their micron scale counterparts. This study shows that at least 13 vol. % carbon nanotubes (CNT) added to nano-aluminum and nano-copper oxide particles (nAl + CuO) eliminates ESD ignition sensitivity. The CNT act as a conduit for electric energy and directs electric charge through the powder to desensitize the reactive mixture to ignition. For nanoparticles, the required CNT concentration for desensitizing ESD ignition acts as a diluent to quench energy propagation.

  5. Dry powder mixes comprising phase change materials

    DOE Patents [OSTI]

    Salyer, I.O.

    1994-12-06

    A free flowing, conformable powder-like mix of silica particles and a phase change material (PCM) is provided. The silica particles have a critical size of about 0.005 to about 0.025 microns and the PCM must be added to the silica in an amount of 75% or less PCM per combined weight of silica and PCM. The powder-like mix can be used in tableware items, medical wraps, tree wraps, garments, quilts and blankets, and particularly in applications for heat protection for heat sensitive items, such as aircraft flight recorders, and for preventing brake fade in automobiles, buses, trucks and aircraft. 3 figures.

  6. Dry powder mixes comprising phase change materials

    DOE Patents [OSTI]

    Salyer, I.O.

    1995-12-26

    A free flowing, conformable powder-like mix of silica particles and a phase change material (PCM) is provided. The silica particles have a critical size of about 0.005 to about 0.025 microns and the PCM must be added to the silica in an amount of 75% or less PCM per combined weight of silica and PCM. The powder-like mix can be used in tableware items, medical wraps, tree wraps, garments, quilts and blankets, and particularly in applications for heat protection for heat sensitive items, such as aircraft flight recorders, and for preventing brake fade in automobiles, buses, trucks and aircraft. 3 figs.

  7. Dry powder mixes comprising phase change materials

    DOE Patents [OSTI]

    Salyer, Ival O.

    1995-01-01

    A free flowing, conformable powder-like mix of silica particles and a phase change material (PCM) is provided. The silica particles have a critical size of about 0.005 to about 0.025 microns and the PCM must be added to the silica in an amount of 75% or less PCM per combined weight of silica and PCM. The powder-like mix can be used in tableware items, medical wraps, tree wraps, garments, quilts and blankets, and particularly in applications for heat protection for heat sensitive items, such as aircraft flight recorders, and for preventing brake fade in automobiles, buses, trucks and aircraft.

  8. Dry powder mixes comprising phase change materials

    DOE Patents [OSTI]

    Salyer, Ival O.

    1994-01-01

    A free flowing, conformable powder-like mix of silica particles and a phase change material (PCM) is provided. The silica particles have a critical size of about 0.005 to about 0.025 microns and the PCM must be added to the silica in an amount of 75% or less PCM per combined weight of silica and PCM. The powder-like mix can be used in tableware items, medical wraps, tree wraps, garments, quilts and blankets, and particularly in applications for heat protection for heat sensitive items, such as aircraft flight recorders, and for preventing brake fade in automobiles, buses, trucks and aircraft.

  9. Process for preparing active oxide powders

    DOE Patents [OSTI]

    Berard, Michael F.; Hunter, Jr., Orville; Shiers, Loren E.; Dole, Stephen L.; Scheidecker, Ralph W.

    1979-02-20

    An improved process for preparing active oxide powders in which cation hydroxide gels, prepared in the conventional manner are chemically dried by alternately washing the gels with a liquid organic compound having polar characteristics and a liquid organic compound having nonpolar characteristics until the mechanical water is removed from the gel. The water-free cation hydroxide is then contacted with a final liquid organic wash to remove the previous organic wash and speed drying. The dried hydroxide treated in the conventional manner will form a highly sinterable active oxide powder.

  10. Synthesis of ultrafine powders by microwave heating

    DOE Patents [OSTI]

    Meek, Thomas T.; Sheinberg, Haskell; Blake, Rodger D.

    1988-01-01

    A method of synthesizing ultrafine powders using microwaves is described. A water soluble material is dissolved in water and the resulting aqueous solution is exposed to microwaves until the water has been removed. The resulting material is an ultrafine powder. This method can be used to make Al.sub.2 O.sub.3, NiO+Al.sub.2 O.sub.3 and NiO as well as a number of other materials including GaBa.sub.2 Cu.sub.3 O.sub.x.

  11. Synthesis of ultrafine powders by microwave heating

    DOE Patents [OSTI]

    Meek, T.T.; Sheinberg, H.; Blake, R.D.

    1987-04-24

    A method of synthesizing ultrafine powders using microwaves is described. A water soluble material is dissolved in water and the resulting aqueous solution is exposed to microwaves until the water has dissolved. The resulting material is an ultrafine powder. This method can be used to make Al/sub 2/O/sub 3/, NiO /plus/ Al/sub 2/O/sub 3/ and NiO as well as a number of other materials including GaBa/sub 2/Cu/sub 3/O/sub x/. 1 tab.

  12. Advanced NDE Technologies for Powder Metal Components

    SciTech Connect (OSTI)

    Martin, P; Haskins, J; Thomas, G; Dolan, K

    2003-05-01

    Nondestructive evaluation encompasses numerous technologies that assess materials and determine important properties. This paper demonstrates the applicability of several of these technologies to the field of powder metallurgy. The usual application of nondestructive evaluation is to detect and quantify defects in fully sintered product. But probably its most appealing role is to sense problems earlier in the manufacturing process to avoid making defects at all. Also nondestructive evaluation can be incorporated into the manufacturing processes to monitor important parameters and control the processes to produce defect free product. Nondestructive evaluation can characterize powders, evaluate components in the green state, monitor the sintering process, and inspect the final component.

  13. Large-scale and shape-controlled synthesis and characterization of nanorod-like nickel powders under microwave radiation

    SciTech Connect (OSTI)

    Guo, Yajie; Wang, Guangjian; Wang, Yuran; Huang, Yanhong; Wang, Fei

    2012-01-15

    Graphical abstract: The nanorod-like pure nickel were fabricated via hydrothermal liquid phase reduction route under microwave irradiation with hydrazine hydrate as a reducing agent as well as polyvinyl alcohol as a dispersant and/or structure directing agent. The materials were characterized by XRD, SEM, EDS, HRTEM, and selected-area electron diffraction, etc. The lattice expansion for Ni powders was explained in detail. As-prepared Ni sample was of obvious shape anisotropy with length diameter ratio of 5. Magnetic measurements shown that the magnetic properties of Ni nanorod-like (fcc) were quite different from those of hexagonal closed-packed (hcp) Ni nanoparticles. Highlights: Black-Right-Pointing-Pointer The synthesis of nanorod-like nickel under microwave irradiation. Black-Right-Pointing-Pointer Nitrogen generated in reaction as a shielding gas. Black-Right-Pointing-Pointer The lattice expansion for Ni powders was explained in detail. Black-Right-Pointing-Pointer Magnetic properties of Ni were quite different from those of Ni nanoparticles. -- Abstract: The nanorod-like nickel powders were fabricated via hydrothermal liquid phase reduction route under microwave irradiation with hydrazine hydrate as a reducing agent as well as polyvinyl alcohol as a dispersant and/or structure directing agent. The morphology and structure of as-prepared products could be easily tuned by adjusting process parameters such as pH value and microwave irradiation time. The resulting materials were characterized by X-ray diffraction (XRD), scanning electron microscope, transmission electron microscopy and selected-area electron diffraction (SAED). The results demonstrated that pure nickel powders with face-centered cubic (fcc) structure were prepared at relatively mild condition and no characteristic peaks of nickel oxide in the XRD pattern were found. The phenomenon of lattice expansion for Ni powders was explained in details according to the XRD theory. As-prepared Ni sample was

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

    Energy.gov [DOE]

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

  15. Flexible sample environment for high resolution neutron imaging at high temperatures in controlled atmosphere

    SciTech Connect (OSTI)

    Makowska, Małgorzata G.; Theil Kuhn, Luise; Cleemann, Lars N.; Lauridsen, Erik M.; Bilheux, Hassina Z.; Molaison, Jamie J.; Santodonato, Louis J.; Tremsin, Anton S.; Grosse, Mirco; Morgano, Manuel; Kabra, Saurabh; Strobl, Markus

    2015-12-17

    In high material penetration by neutrons allows for experiments using sophisticated sample environments providing complex conditions. Thus, neutron imaging holds potential for performing in situ nondestructive measurements on large samples or even full technological systems, which are not possible with any other technique. Our paper presents a new sample environment for in situ high resolution neutron imaging experiments at temperatures from room temperature up to 1100 degrees C and/or using controllable flow of reactive atmospheres. The design also offers the possibility to directly combine imaging with diffraction measurements. Design, special features, and specification of the furnace are described. In addition, examples of experiments successfully performed at various neutron facilities with the furnace, as well as examples of possible applications are presented. Our work covers a broad field of research from fundamental to technological investigations of various types of materials and components.

  16. Flexible sample environment for high resolution neutron imaging at high temperatures in controlled atmosphere

    DOE PAGES-Beta [OSTI]

    Makowska, Małgorzata G.; Theil Kuhn, Luise; Cleemann, Lars N.; Lauridsen, Erik M.; Bilheux, Hassina Z.; Molaison, Jamie J.; Santodonato, Louis J.; Tremsin, Anton S.; Grosse, Mirco; Morgano, Manuel; et al

    2015-12-17

    In high material penetration by neutrons allows for experiments using sophisticated sample environments providing complex conditions. Thus, neutron imaging holds potential for performing in situ nondestructive measurements on large samples or even full technological systems, which are not possible with any other technique. Our paper presents a new sample environment for in situ high resolution neutron imaging experiments at temperatures from room temperature up to 1100 degrees C and/or using controllable flow of reactive atmospheres. The design also offers the possibility to directly combine imaging with diffraction measurements. Design, special features, and specification of the furnace are described. In addition,more » examples of experiments successfully performed at various neutron facilities with the furnace, as well as examples of possible applications are presented. Our work covers a broad field of research from fundamental to technological investigations of various types of materials and components.« less

  17. Flexible sample environment for high resolution neutron imaging at high temperatures in controlled atmosphere

    SciTech Connect (OSTI)

    Makowska, Małgorzata G.; Theil Kuhn, Luise; Cleemann, Lars N.; Lauridsen, Erik M.; Bilheux, Hassina Z.; Molaison, Jamie J.; Santodonato, Louis J.; Tremsin, Anton S.; Grosse, Mirco; Morgano, Manuel; Kabra, Saurabh; Strobl, Markus

    2015-12-15

    High material penetration by neutrons allows for experiments using sophisticated sample environments providing complex conditions. Thus, neutron imaging holds potential for performing in situ nondestructive measurements on large samples or even full technological systems, which are not possible with any other technique. This paper presents a new sample environment for in situ high resolution neutron imaging experiments at temperatures from room temperature up to 1100 °C and/or using controllable flow of reactive atmospheres. The design also offers the possibility to directly combine imaging with diffraction measurements. Design, special features, and specification of the furnace are described. In addition, examples of experiments successfully performed at various neutron facilities with the furnace, as well as examples of possible applications are presented. This covers a broad field of research from fundamental to technological investigations of various types of materials and components.

  18. Diffraction gratings used as identifying markers

    DOE Patents [OSTI]

    Deason, Vance A.; Ward, Michael B.

    1991-01-01

    A finely detailed defraction grating is applied to an object as an identifier or tag which is unambiguous, difficult to duplicate, or remove and transfer to another item, and can be read and compared with prior readings with relative ease. The exact pattern of the defraction grating is mapped by diffraction moire techniques and recorded for comparison with future readings of the same grating.

  19. High intensity, pulsed thermal neutron source

    DOE Patents [OSTI]

    Carpenter, J.M.

    1973-12-11

    This invention relates to a high intensity, pulsed thermal neutron source comprising a neutron-producing source which emits pulses of fast neutrons, a moderator block adjacent to the last neutron source, a reflector block which encases the fast neutron source and the moderator block and has a thermal neutron exit port extending therethrough from the moderator block, and a neutron energy- dependent decoupling reflector liner covering the interior surfaces of the thermal neutron exit port and surrounding all surfaces of the moderator block except the surface viewed by the thermal neutron exit port. (Official Gazette)

  20. Imaging surface atomic structure with energy dependent electron diffraction

    SciTech Connect (OSTI)

    Tobin, J.

    1994-11-15

    The general concepts and approaches to extracting structural information from imaging with electron diffraction are outlined.

  1. FAST NEUTRON SPECTROMETER

    DOE Patents [OSTI]

    Davis, F.J.; Hurst, G.S.; Reinhardt, P.W.

    1959-08-18

    An improved proton recoil spectrometer for determining the energy spectrum of a fast neutron beam is described. Instead of discriminating against and thereby"throwing away" the many recoil protons other than those traveling parallel to the neutron beam axis as do conventional spectrometers, this device utilizes protons scattered over a very wide solid angle. An ovoidal gas-filled recoil chamber is coated on the inside with a scintillator. The ovoidal shape of the sensitive portion of the wall defining the chamber conforms to the envelope of the range of the proton recoils from the radiator disposed within the chamber. A photomultiplier monitors the output of the scintillator, and a counter counts the pulses caused by protons of energy just sufficient to reach the scintillator.

  2. COMPOSITE NEUTRONIC REACTOR

    DOE Patents [OSTI]

    Menke, J.R.

    1963-06-11

    This patent relates to a reactor having a core which comprises an inner active region and an outer active region, each region separately having a k effective less than one and a k infinity greater than one. The inner and outer regions in combination have a k effective at least equal to one and each region contributes substantially to the k effective of the reactor core. The inner region has a low moderator to fuel ratio such that the majority of fissions occurring therein are induced by neutrons having energies greater than thermal. The outer region has a high moderator to fuel ratio such that the majority of fissions occurring therein are induced by thermal neutrons. (AEC)

  3. Scintillation neutron detectors

    SciTech Connect (OSTI)

    Davidson, J.B.

    1984-01-01

    Two basic types of scintillation area neutron detectors are reviewed. The first is the prompt detector which uses photomultipliers to convert the neutron scintillations to electrical pulses. These signals are combined in weighting or encoding circuits to give event location. Several embodiments of the weighted and coded scintillator approach are mentioned. The second type of scintillation detector is based on television techniques and has a delayed readout. In this method all the light (or as much as possible) is either focused with a fast lens or is coupled by being put in direct contact with the fiber-optic faceplate of an image intensifier tube. The light from the phosphor screen is intensified and coupled to a television camera tube instead of a photomultiplier, and further amplification is produced in the camera tube by accelerating the photoelectrons in order to produce secondary electrons. (LEW)

  4. Porous material neutron detector

    DOE Patents [OSTI]

    Diawara, Yacouba; Kocsis, Menyhert

    2012-04-10

    A neutron detector employs a porous material layer including pores between nanoparticles. The composition of the nanoparticles is selected to cause emission of electrons upon detection of a neutron. The nanoparticles have a maximum dimension that is in the range from 0.1 micron to 1 millimeter, and can be sintered with pores thereamongst. A passing radiation generates electrons at one or more nanoparticles, some of which are scattered into a pore and directed toward a direction opposite to the applied electrical field. These electrons travel through the pore and collide with additional nanoparticles, which generate more electrons. The electrons are amplified in a cascade reaction that occurs along the pores behind the initial detection point. An electron amplification device may be placed behind the porous material layer to further amplify the electrons exiting the porous material layer.

  5. Proton recoil scintillator neutron rem meter

    DOE Patents [OSTI]

    Olsher, Richard H.; Seagraves, David T.

    2003-01-01

    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.

  6. Fast neutron imaging device and method

    DOE Patents [OSTI]

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

    2014-02-11

    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.

  7. NEUTRONIC REACTOR SYSTEM

    DOE Patents [OSTI]

    Goett, J.J.

    1961-01-24

    A system is described which includes a neutronic reactor containing a dispersion of fissionable material in a liquid moderator as fuel and a conveyor to which a portion of the dispersion may be passed and wherein the self heat of the slurry evaporates the moderator. Means are provided for condensing the liquid moderator and returning it to the reactor and for conveying the dried fissionable material away from the reactor.

  8. THERMAL NEUTRONIC REACTOR

    DOE Patents [OSTI]

    Spinrad, B.I.

    1960-01-12

    A novel thermal reactor was designed in which a first reflector formed from a high atomic weight, nonmoderating material is disposed immediately adjacent to the reactor core. A second reflector composed of a moderating material is disposed outwardly of the first reflector. The advantage of this novel reflector arrangement is that the first reflector provides a high slow neutron flux in the second reflector, where irradiation experiments may be conducted with a small effect on reactor reactivity.

  9. Neutron Science and Technology

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    3 Neutron Science and Technology From a mountaintop in Mexico where we investigate gamma rays, to underground laboratories where we study the behavior of plutonium under extreme conditions, our research spans the spectrum from fundamental to applied. Contact Us Group Leader Frank Merrill Email Deputy Group Leader David Oro Email Deputy Group Leader Keith Rielage Email Group Office Email Inner workings of a wristwatch that was imaged by a new proton microscope At right, a wristwatch was one of

  10. European Neutron Activation System.

    Energy Science and Technology Software Center (OSTI)

    2013-01-11

    Version 03 EASY-2010 (European Activation System) consists of a wide range of codes, data and documentation all aimed at satisfying the objective of calculating the response of materials irradiated in a neutron flux. The main difference from the previous version is the upper energy limit, which has increased from 20 to 60 MeV. It is designed to investigate both fusion devices and accelerator based materials test facilities that will act as intense sources of high-energymore » neutrons causing significant activation of the surrounding materials. The very general nature of the calculational method and the data libraries means that it is applicable (with some reservations) to all situations (e.g. fission reactors or neutron sources) where materials are exposed to neutrons below 60 MeV. EASY can be divided into two parts: data and code development tools and user tools and data. The former are required to develop the latter, but EASY users only need to be able to use the inventory code FISPACT and be aware of the contents of the EAF library (the data source). The complete EASY package contains the FISPACT-2007 inventory code, the EAF-2003, EAF-2005, EAF-2007 and EAF-2010 libraries, and the EASY User Interface for the Window version. The activation package EASY-2010 is the result of significant development to extend the upper energy range from 20 to 60 MeV so that it is capable of being used for IFMIF calculations. The EAF-2010 library contains 66,256 reactions, almost five times more than in EAF-2003 (12,617). Deuteron-induced and proton-induced cross section libraries are also included, and can be used with EASY to enable calculations of the activation due to deuterons and proton [2].« less

  11. Phase-shifting point diffraction interferometer phase grating designs

    DOE Patents [OSTI]

    Naulleau, Patrick (Oakland, CA)

    2001-01-01

    Diffraction phase gratings are employed in phase-shifting point diffraction interferometers to improve the interferometric fringe contrast. The diffraction phase grating diffracts a zeroth-order diffraction of light at a first power level to the test-beam window of a mask that is positioned at the image plane and a first-order diffraction at a second power to the reference-beam pinhole. The diffraction phase grating is preferably selected to yield a desired ratio of the first power level to second power level.

  12. 2010 Neutron Review: ORNL Neutron Sciences Progress Report (Technical...

    Office of Scientific and Technical Information (OSTI)

    ... (6) Changing the World of Data Acquisition - Researchers at SNS are starting to ... Country of Publication: United States Language: English Subject: neutron science; ...

  13. Review of Non-Neutron and Neutron Nuclear Data, 2004

    SciTech Connect (OSTI)

    Holden, Norman E.

    2005-05-24

    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.

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

    SciTech Connect (OSTI)

    HOLDEN, N.E.

    2004-09-26

    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.

  15. NEUTRONIC REACTOR CORE

    DOE Patents [OSTI]

    Thomson, W.B.; Corbin, A. Jr.

    1961-07-18

    An improved core for a gas-cooled power reactor which admits gas coolant at high temperatures while affording strong integral supporting structure and efficient moderation of neutrons is described. The multiplicities of fuel elements constituting the critical amassment of fissionable material are supported and confined by a matrix of metallic structure which is interspersed therebetween. Thermal insulation is interposed between substantially all of the metallic matrix and the fuel elements; the insulation then defines the principal conduit system for conducting the coolant gas in heat-transfer relationship with the fuel elements. The metallic matrix itseif comprises a system of ducts through which an externally-cooled hydrogeneous liquid, such as water, is circulated to serve as the principal neutron moderant for the core and conjointly as the principal coolant for the insulated metallic structure. In this way, use of substantially neutron transparent metals, such as aluminum, becomes possible for the supporting structure, despite the high temperatures of the proximate gas. The Aircraft Nuclear Propulsion program's "R-1" reactor design is a preferred embodiment.

  16. Neutron instrumentation for biology

    SciTech Connect (OSTI)

    Mason, S.A.

    1994-12-31

    In the October 1994 round of proposals at the ILL, the external biology review sub- committee was asked to allocate neutron beam time to a wide range of experiments, on almost half the total number of scheduled neutron instruments: on 3 diffractometers, on 3 small angle scattering instruments, and on some 6 inelastic scattering spectrometers. In the 3.5 years since the temporary reactor shutdown, the ILL`s management structure has been optimized, budgets and staff have been trimmed, the ILL reactor has been re-built, and many of the instruments up-graded, many powerful (mainly Unix) workstations have been introduced, and the neighboring European Synchrotron Radiation Facility has established itself as the leading synchrotron radiation source and has started its official user program. The ILL reactor remains the world`s most intense dedicated neutron source. In this challenging context, it is of interest to review briefly the park of ILL instruments used to study the structure and energetics of small and large biological systems. A brief summary will be made of each class of experiments actually proposed in the latest ILL proposal round.

  17. NEUTRON MEASURING METHOD AND APPARATUS

    DOE Patents [OSTI]

    Seaborg, G.T.; Friedlander, G.; Gofman, J.W.

    1958-07-29

    A fast neutron fission detecting apparatus is described consisting of a source of fast neutrons, an ion chamber containing air, two electrodes within the ion chamber in confronting spaced relationship, a high voltage potential placed across the electrodes, a shield placed about the source, and a suitable pulse annplifier and recording system in the electrode circuit to record the impulse due to fissions in a sannple material. The sample material is coated onto the active surface of the disc electrode and shielding means of a material having high neutron capture capabilities for thermal neutrons are provided in the vicinity of the electrodes and about the ion chamber so as to absorb slow neutrons of thermal energy to effectively prevent their diffusing back to the sample and causing an error in the measurement of fast neutron fissions.

  18. Neutron scattering and absorption properties

    SciTech Connect (OSTI)

    Holden, N.E.

    1993-12-01

    The Table in this report presents an evaluated set of values for the experimental quantities, which characterize the properties for scattering and absorption of neutrons. The neutron cross section is given for room temperature neutrons, 20.43{degree}C, corresponds to a thermal neutron energy of 0.0253 electron volts (eV) or a neutron velocity of 2200 meters/second. The neutron resonance integral is defined over the energy range from 0.5 eV to 0.1 {times} 10{sup 6} eV, or 0.1 MeV. A list of the major references used is given below. The literature cutoff data is October 1993. Uncertainties are given in parentheses. Parentheses with two or more numbers indicate values to the excited states(s) and to the ground state of the product nucleus.

  19. Large-volume protein crystal growth for neutron macromolecular crystallography

    SciTech Connect (OSTI)

    Ng, Joseph D.; Baird, James K.; Coates, Leighton; Garcia-Ruiz, Juan M.; Hodge, Teresa A.; Huang, Sijay

    2015-03-30

    Neutron macromolecular crystallography (NMC) is the prevailing method for the accurate determination of the positions of H atoms in macromolecules. As neutron sources are becoming more available to general users, finding means to optimize the growth of protein crystals to sizes suitable for NMC is extremely important. Historically, much has been learned about growing crystals for X-ray diffraction. However, owing to new-generation synchrotron X-ray facilities and sensitive detectors, protein crystal sizes as small as in the nano-range have become adequate for structure determination, lessening the necessity to grow large crystals. Here, some of the approaches, techniques and considerations for the growth of crystals to significant dimensions that are now relevant to NMC are revisited. We report that these include experimental strategies utilizing solubility diagrams, ripening effects, classical crystallization techniques, microgravity and theoretical considerations.

  20. Large-volume protein crystal growth for neutron macromolecular crystallography

    DOE PAGES-Beta [OSTI]

    Ng, Joseph D.; Baird, James K.; Coates, Leighton; Garcia-Ruiz, Juan M.; Hodge, Teresa A.; Huang, Sijay

    2015-03-30

    Neutron macromolecular crystallography (NMC) is the prevailing method for the accurate determination of the positions of H atoms in macromolecules. As neutron sources are becoming more available to general users, finding means to optimize the growth of protein crystals to sizes suitable for NMC is extremely important. Historically, much has been learned about growing crystals for X-ray diffraction. However, owing to new-generation synchrotron X-ray facilities and sensitive detectors, protein crystal sizes as small as in the nano-range have become adequate for structure determination, lessening the necessity to grow large crystals. Here, some of the approaches, techniques and considerations for themore » growth of crystals to significant dimensions that are now relevant to NMC are revisited. We report that these include experimental strategies utilizing solubility diagrams, ripening effects, classical crystallization techniques, microgravity and theoretical considerations.« less

  1. Elastic stability of high dose neutron irradiated spinel

    SciTech Connect (OSTI)

    Li, Z.; Chan, S.K.; Garner, F.A.

    1995-04-01

    The objective of this effort is to identify ceramic materials that are suitable for fusion reactor applications. Elastic constants (C{sub 11}, C{sub 12}, and C{sub 44}) of spinel (MgAl{sub 2}O{sub 4}) single crystals irradiated to very high neutron fluences have geen measured by an ultrasonic technique. Although results of a neutron diffraction study show that cation occupation sites are significantly changed in the irradiated samples, no measurable differences occurred in their elastic properties. In order to understand such behavior, the elastic properties of a variety of materials with either normal or inverse spinel structures were studied. The cation valence and cation distribution appear to have little influence on the elastic properties of spinel materials.

  2. APPARATUS FOR CONTROLLING NEUTRONIC REACTORS

    DOE Patents [OSTI]

    Dietrich, J.R.; Harrer, J.M.

    1958-09-16

    A device is described for rapidly cortrolling the reactivity of an active portion of a reactor. The inveniion consists of coaxially disposed members each having circumferenital sections of material having dlfferent neutron absorbing characteristics and means fur moving the members rotatably and translatably relative to each other within the active portion to vary the neutron flux therein. The angular and translational movements of any member change the neutron flux shadowing effect of that member upon the other member.

  3. Advanced Neutron Source (ANS) Project

    SciTech Connect (OSTI)

    Campbell, J.H.; Selby, D.L.; Harrington, R.M.; Peretz, F.J.

    1991-02-01

    This report discusses the research and development, design and safety of the Advanced Neutron Source at Oak Ridge National Laboratory. (LSP)

  4. Portable neutron spectrometer and dosimeter

    DOE Patents [OSTI]

    Waechter, D.A.; Erkkila, B.H.; Vasilik, D.G.

    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.

  5. NEUTRON ABSORPTION AND SHIELDING DEVICE

    DOE Patents [OSTI]

    Axelrad, I.R.

    1960-06-21

    A neutron absorption and shielding device is described which is adapted for mounting in a radiation shielding wall surrounding a radioactive area through which instrumentation leads and the like may safely pass without permitting gamma or neutron radiation to pass to the exterior. The shielding device comprises a container having at least one nonrectilinear tube or passageway means extending therethrough, which is adapted to contain instrumentation leads or the like, a layer of a substance capable of absorbing gamma rays, and a solid resinous composition adapted to attenuate fast-moving neutrons and capture slow- moving or thermal neutrons.

  6. Portable neutron spectrometer and dosimeter

    DOE Patents [OSTI]

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

    1985-01-01

    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.

  7. NEUTRON IMAGING, RADIOGRAPHY AND TOMOGRAPHY.

    SciTech Connect (OSTI)

    SMITH,G.C.

    2002-03-01

    Neutrons are an invaluable probe in a wide range of scientific, medical and commercial endeavors. Many of these applications require the recording of an image of the neutron signal, either in one-dimension or in two-dimensions. We summarize the reactions of neutrons with the most important elements that are used for their detection. A description is then given of the major techniques used in neutron imaging, with emphasis on the detection media and position readout principle. Important characteristics such as position resolution, linearity, counting rate capability and sensitivity to gamma-background are discussed. Finally, the application of a subset of these instruments in radiology and tomography is described.

  8. Pulsed neutrons: one year of experience with the new source at Argonne National Laboratory

    SciTech Connect (OSTI)

    Lander, G.H.

    1982-01-01

    The Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory is a spallation neutron source based on a 500-MeV proton accelerator operating at 30 Hz and with an average proton current of approx. 10 ..mu..A. Neutron-scattering instruments for elastic scattering include two powder diffractometers, a single-crystal diffractometer based on the Laue method and employing a large (30 x 30 cm) position-sensitive scintillation detector, a small-angle diffractometer using a position-sensitive detector, and a polarized-neutron diffractometer which will utilize the spin-refrigerator device to obtain a beam of white polarized neutrons. For inelastic scattering, we presently have the crystal-analyzer spectrometer and two chopper spectrometers capable of providing monoenergetic incident neutron beams of between 100 and 600 MeV. From its inception IPNS has been operating in a user mode and the selection of experiments is made by a Program Committee twice a year on the basis of the scientific merit of submitted proposals.

  9. QER - Comment of Powder River Energy Corporation | Department...

    Energy Savers

    Powder River Energy Corporation is an equal opportunity provider and employer. ... Note: PrivilegedConfidential information may be ...

  10. Phase-shifting point diffraction interferometer

    DOE Patents [OSTI]

    Medecki, H.

    1998-11-10

    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.

  11. Phase-shifting point diffraction interferometer

    DOE Patents [OSTI]

    Medecki, Hector

    1998-01-01

    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.

  12. Manufacture and Development of Multilayer Diffraction Gratings

    SciTech Connect (OSTI)

    Keck, J.; Oliver, J.B.; Kessler, T.J.; Huang, H.; Barone, J.; Hettrick, J.; Rigatti, A.L.; Hoover, T.; Marshall, K.L.; Schmid, A.W.; Kozlov, A.; Kosc, T.Z.

    2006-03-01

    The OMEGA EP Facility includes two high-energy, short-pulse laser beams that will be focused to high intensity in the OMEGA target chamber, providing backlighting of compressed fusion targets and investigating the fast-ignition concept. To produce 2.6 kJ output energy per beam, developments in grating compressor technology are required. Gold-coated diffraction gratings limit on-target energy because of their low damage fluence. Multilayer dielectric (MLD) gratings have shown promise as high-damage-threshold, high-efficiency diffraction gratings suitable for use in high-energy chirped-pulse amplification. This paper details the manufacture and development of these gratings, including the specifics of the MLD coating, holographic lithography, reactive ion etching, reactive ion-beam cleaning, and wet chemical cleaning.

  13. Periodically distributed objects with quasicrystalline diffraction pattern

    SciTech Connect (OSTI)

    Wolny, Janusz Strzalka, Radoslaw; Kuczera, Pawel

    2015-03-30

    It is possible to construct fully periodically distributed objects with a diffraction pattern identical to the one obtained for quasicrystals. These objects are probability distributions of distances obtained in the statistical approach to aperiodic structures distributed periodically. The diffraction patterns have been derived by using a two-mode Fourier transform—a very powerful method not used in classical crystallography. It is shown that if scaling is present in the structure, this two-mode Fourier transform can be reduced to a regular Fourier transform with appropriately rescaled scattering vectors and added phases. Detailed case studies for model sets 1D Fibonacci chain and 2D Penrose tiling are discussed. Finally, it is shown that crystalline, quasicrystalline, and approximant structures can be treated in the same way.

  14. Diffractive and exclusive measurements at CDF

    SciTech Connect (OSTI)

    Gallinaro, Michele; /Rockefeller U.

    2006-06-01

    Experimental results from the CDF experiment at the Tevatron in p{bar p} collisions at {radical}s = 1.96 TeV are presented on the diffractive structure function at different values of the exchanged momentum transfer squared in the range 0 < Q{sup 2} < 10,000 GeV{sup 2}, on the four-momentum transfer |t| distribution in the region 0 < |t| < 1 GeV{sup 2} for both soft and hard diffractive events up to Q{sup 2} {approx} 4,500 GeV{sup 2}, and on the first experimental evidence of exclusive production in both dijet and diphoton events. A novel technique to align the Roman Pot detectors is also presented.

  15. QCD and hard diffraction at the LHC

    SciTech Connect (OSTI)

    Albrow, Michael G.; /Fermilab

    2005-09-01

    As an introduction to QCD at the LHC the author gives an overview of QCD at the Tevatron, emphasizing the high Q{sup 2} frontier which will be taken over by the LHC. After describing briefly the LHC detectors the author discusses high mass diffraction, in particular central exclusive production of Higgs and vector boson pairs. The author introduces the FP420 project to measure the scattered protons 420m downstream of ATLAS and CMS.

  16. Advances in passive neutron instruments for safeguards use

    SciTech Connect (OSTI)

    Menlove, H.O.; Krick, M.S.; Langner, D.G.; Miller, M.C.; Stewart, J.E.

    1994-02-01

    Passive neutron and other nondestructive assay techniques have been used extensively by the International Atomic Energy Agency to verify plutonium metal, powder, mixed oxide, pellets, rods, assemblies, scrap, and liquids. Normally, the coincidence counting rate is used to measure the {sup 240}Pu-effective mass and gamma-ray spectrometry or mass spectrometry is used to verify the plutonium isotopic ratios. During the past few years, the passive neutron detectors have been installed in plants and operated in the unattended/continuous mode. These radiation data with time continuity have made it possible to use the totals counting rate to monitor the movement of nuclear material. Monte Carlo computer codes have been used to optimize the detector designs for specific applications. The inventory sample counter (INVS-III) has been designed to have a higher efficiency (43%) and a larger uniform counting volume than the original INVS. Data analyses techniques have been developed, including the ``known alpha`` and ``known multiplication`` methods that depend on the sample. For scrap and other impure or poorly characterized samples, we have developed multiplicity counting, initially implemented in the plutonium scrap multiplicity counter. For large waste containers such as 200-L drums, we have developed the add-a-source technique to give accurate corrections for the waste-matrix materials. This paper summarizes recent developments in the design and application of passive neutron assay systems.

  17. Neutron multiplicity ,easurements With 3He alternative: Straw neutron detectors

    DOE PAGES-Beta [OSTI]

    Mukhopadhyay, Sanjoy; Wolff, Ronald S.; Meade, John A.; Detweiler, Ryan; Maurer, Richard J.; Mitchell, Stephen E.; Guss, Paul P.; Lacy, Jeffrey L.; Sun, Liang; Athanasiades, Athanasios

    2015-01-27

    Counting neutrons emitted by special nuclear material (SNM) and differentiating them from the background neutrons of various origins is the most effective passive means of detecting SNM. Unfortunately, neutron detection, counting, and partitioning in a maritime environment are complex due to the presence of high-multiplicity spallation neutrons (commonly known as “ship effect”) and to the complicated nature of the neutron scattering in that environment. In this study, a prototype neutron detector was built using 10B as the converter in a special form factor called “straws” that would address the above problems by looking into the details of multiplicity distributions ofmore » neutrons originating from a fissioning source. This paper describes the straw neutron multiplicity counter (NMC) and assesses the performance with those of a commercially available fission meter. The prototype straw neutron detector provides a large-area, efficient, lightweight, more granular (than fission meter) neutron-responsive detection surface (to facilitate imaging) to enhance the ease of application of fission meters. Presented here are the results of preliminary investigations, modeling, and engineering considerations leading to the construction of this prototype. This design is capable of multiplicity and Feynman variance measurements. This prototype may lead to a near-term solution to the crisis that has arisen from the global scarcity of 3He by offering a viable alternative to fission meters. This paper describes the work performed during a 2-year site-directed research and development (SDRD) project that incorporated straw detectors for neutron multiplicity counting. The NMC is a two-panel detector system. We used 10B (in the form of enriched boron carbide: 10B4C) for neutron detection instead of 3He. In the first year, the project worked with a panel of straw neutron detectors, investigated its characteristics, and developed a data acquisition (DAQ) system to collect

  18. Electroweak bremsstrahlung from neutron-neutron scattering

    SciTech Connect (OSTI)

    Li Yi; Liou, M. K.; Schreiber, W. M.

    2009-09-15

    Background: Nucleon-nucleon (NN) bremsstrahlung processes NN{gamma} (nn{gamma}, np{gamma}, and pp{gamma}) have been extensively investigated. Neutrino-pair bremsstrahlung processes from nucleon-nucleon scattering NN{nu}{nu} (nn{nu}{nu}, np{nu}{nu}, and pp{nu}{nu}) have recently attracted attention in studies of neutrino emission in neutron stars. The calculated NN{nu}{nu} cross sections (or emissivities) are found to be sensitive to the two-nucleon dynamical model used in the calculations. Purpose and Method: A realistic one-boson-exchange (ROBE) model for NN interactions is used to construct the electroweak bremsstrahlung amplitudes using the well-known nucleon electromagnetic and weak interaction vertices. The constructed nn{gamma} and nn{nu}{nu} amplitudes are investigated by applying them to calculate nn{gamma} and nn{nu}{nu} cross sections, respectively. Results: (i) The 190-MeV ROBE nn{gamma} cross sections agree well with those calculated using the TuTts amplitude, but they are in disagreement with those calculated using the Low amplitude. (ii) The calculated nn{nu}{nu} cross sections using the ROBE amplitude at the neutrino-pair energy {omega} = 1 MeV are in quantitative agreement with those calculated by Timmermans et al.[Phys. Rev. C 65, 064007 (2002)], who used the leading-order term of the soft neutrino-pair bremsstrahlung amplitude. Conclusions: The nn{gamma} amplitude in the ROBE approach, which obeys the soft-photon theorem, has a predictive power similar to that of the TuTts amplitude. The nn{nu}{nu} amplitude in the ROBE approach, which is consistent with the soft neutrino-pair bremsstrahlung theorem, has a predictive power similar to that of the soft neutrino-pair bremsstrahlung amplitude of Timmermans et al. in the low neutrino-pair energy region.

  19. LANSCE | Lujan Center | Instruments | Neutron Radiography

    U.S. Department of Energy (DOE) all webpages (Extended Search)

    Neutron Radiography The recently acquired energy-dispersive neutron imaging detector can be used on various Lujan Center beam-lines to combine scattering with imaging. In most...

  20. SciTech Connect: "neutron scattering"

    Office of Scientific and Technical Information (OSTI)

    neutron scattering" Find + Advanced Search Term Search Semantic Search Advanced Search All Fields: "neutron scattering" Semantic Semantic Term Title: Full Text: Bibliographic...