WorldWideScience

Sample records for system neutron diffraction

  1. Neutron diffraction

    International Nuclear Information System (INIS)

    James, M.; Howard, C.J.; Kennedy, S.

    1999-01-01

    Diffraction methods, especially X-ray diffraction, are widely used in materials science. Neutron diffraction is in many ways similar to X-ray diffraction, but is also complementary to the X-ray technique so that in some cases it yields information not accessible using X-rays. Successes of neutron diffraction include the elucidation of the crystal structures of high temperature superconductors and materials that display colossal magnetoresistance, the phase analysis of zirconia engineering ceramics, in depth stress determination in composites, successful determination of the structures of metal hydrides, transition metal polymer complexes and the determination of magnetic structure. A brief description of current studies, using neutron diffraction is given

  2. Neutron diffraction texture analysis of multi-phase systems

    International Nuclear Information System (INIS)

    Brokmeier, H.G.

    1989-01-01

    Neutron diffraction methods for texture analysis are closely parallel to well-known X-ray diffraction techniques. The chief advantage of neutron diffraction over X-ray diffraction, however, arises from the fact that the interaction of neutrons with matter is relatively weak, and consequently the penetration depth of neutrons is 10 2 -10 3 times larger than that of X-rays. Hence neutron diffraction is an efficient tool for measuring textures in multi-phase systems. Based on the high transmission of a neutron beam the effect of anisotropic absorption in multi-phase materials can be neglected in most cases. Moreover, the analysis of bulk textures becomes possible, such that textures in a wide variety of multi-phase systems can be studied which are of special interest in engineering and science (metals, alloys, composites, ceramics and geological specimens). (orig.)

  3. Neutron diffraction

    International Nuclear Information System (INIS)

    Bacon, G.E.

    1983-01-01

    The paper reviews neutron diffraction work from the early studies to the present-day development of the subject. Direct structural investigations were described, including chemical applications associated with single crystal techniques, and magnetic applications identified with powder techniques. The properties of the neutron beams are discussed, as well as the use of polarised beams. (UK)

  4. Neutron diffraction

    International Nuclear Information System (INIS)

    Heger, G.

    1996-01-01

    X-ray diffraction using conventional laboratory equipment and/or synchrotron installations is the most important method for structure analyses. The purpose of this paper is to discuss special cases, for which, in addition to this indispensable part, neutrons are required to solve structural problems. Even though the huge intensity of modern synchrotron sources allows in principle the study of magnetic X-ray scattering the investigation of magnetic structures is still one of the most important applications of neutron diffraction. (author) 15 figs., 1 tab., 10 refs

  5. Neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Heger, G. [Rheinisch-Westfaelische Technische Hochschule Aachen, Inst. fuer Kristallographie, Aachen (Germany)

    1996-12-31

    X-ray diffraction using conventional laboratory equipment and/or synchrotron installations is the most important method for structure analyses. The purpose of this paper is to discuss special cases, for which, in addition to this indispensable part, neutrons are required to solve structural problems. Even though the huge intensity of modern synchrotron sources allows in principle the study of magnetic X-ray scattering the investigation of magnetic structures is still one of the most important applications of neutron diffraction. (author) 15 figs., 1 tab., 10 refs.

  6. Neutron diffraction

    International Nuclear Information System (INIS)

    Howard, C.J.; Kennedy, S.J.

    1994-01-01

    A brief account is given of neutron diffraction techniques. Similarities and differences compared with the more familiar X-ray counterparts are discussed. In certain applications, neutron diffraction can be used to obtain information about materials which would be difficult or even impossible to obtain using other techniques. One spectacular success has been the elucidation, from neutron powder diffraction, of the crystal structures of high critical temperature oxide superconductors. There have been substantial contributions in other fields, and these are illustrated by Australian work. The ability of the neutron to penetrate deeply into most materials has been invoked for in-depth determination of stresses in composites and of phase composition in zirconia ceramics. The unique properties of the neutron have been successfully exploited in studies of metal hydrides, to determine where hydrogen is located, and in magnetic structure determination. There is much interest in studying materials under different conditions of temperature and pressure, and kinetic studies under such conditions are now becoming possible. The article includes information on the principles, the instrumentation with particular reference to the instruments installed around the HIFAR reactor at Lucas Heights, and methods for the interpretation of data. 59 refs., 3 tabs., 16 figs

  7. OrientExpress: A new system for Laue neutron diffraction

    International Nuclear Information System (INIS)

    Ouladdiaf, B.; Archer, J.; McIntyre, G.J.; Hewat, A.W.; Brau, D.; York, S.

    2006-01-01

    A new automatic Laue neutron diffractometer has been developed at the ILL. The system is composed of a goniometer with two tilt stages mounted on an ω-rotation and a scintillator/CCD neutron detector which is mounted on a 2θ arm. All movements are computer controlled. The intensified neutron imaging system is unique and allows electronic capture of neutron Laue diffraction patterns in a much shorter time (few seconds) than conventional film-based methods. The detection system is based upon two high-performance image-intensified CCD cameras coupled to a large-area neutron scintillator. The system is also unique in permitting full back-reflection geometry. A gain of about 100 in efficiency is obtained compared to the conventional film method with comparable spatial resolution. Some examples for Laue patterns are presented and compared to those obtained by film. A quantitative analysis of the integrated intensity of the Laue spots is also made

  8. Neutron diffraction

    International Nuclear Information System (INIS)

    Elcomb, M.M.

    2002-01-01

    Full text: Thermal neutrons have a particular combination of properties, which make them the probe of choice for a wide range of scattering applications. They penetrate most materials easily, the wavelength matches interatomic spacings, the energy matches the atomic vibrational energies and the magnetic moment allows them to uniquely interact with magnetic structures. Their widely varying scattering length is also used to advantage. It enables the determination of light atoms in the presence of heavy ones: hydrogen in organic molecules, and oxygen in the high Tc superconductors for example, or solving problems in alloy systems where distinction of atoms, which are neighbours in the periodic table, is required. In the 50 years since thermal neutron beams have been used for research there has been a steady increase in applications as technology has advanced. This also applies to the environments in which the materials are studied. In-situ studies at other than ambient temperatures, pressures and magnetic fields are now routine. By using multiple detector channels in powder instruments the data collection rate has increased by an order of magnitude to some extent compensating for the diffuse nature of the neutron source. The applications of neutron scattering are becoming more industrially oriented. The talk will highlight the complementarity of neutrons to other more readily available techniques, and give examples of recent research and applications. Copyright (2002) Australian X-ray Analytical Association Inc

  9. Neutron powder diffraction

    International Nuclear Information System (INIS)

    David, W.I.F.

    1990-01-01

    Neutron powder diffraction is a powerful technique that provides a detailed description of moderately complex crystal structures. This is nowhere more apparent than in the area of high temperature superconductors where neutron powder diffraction has provided precise structural and magnetic information, not only under ambient conditions but also at high and low temperatures and high pressures. Outside superconductor research, the variety of materials studied by neutron powder diffraction is equally impressive including zeolites, fast ionic conductors, permanent magnets and materials undergoing phase transitions. Recent advances that include high resolution studies and real-time crystallography are presented. Future possibilities of neutron powder diffraction are discussed

  10. Neutron diffraction on pulsed sources

    Science.gov (United States)

    Aksenov, V. L.; Balagurov, A. M.

    2016-03-01

    The current capabilities of and major scientific problems solved by time-of-flight neutron diffraction are reviewed. The reasons for the rapid development of the method over the last two decades have been mainly the emergence of third-generation pulsed sources with a megawatt time-averaged power and advances in neutron optical devices and detector systems. The paper discusses some historical aspects of time-of-flight neutron diffraction and examines the contribution to this method from F L Shapiro, the centennial of whose birth was celebrated in 2015. The state of the art with respect to neutron sources for studies on extracted beams is reviewed in a special section.

  11. Application of 2-dimensional coordinate system conversion in stress measurements with neutron diffraction

    International Nuclear Information System (INIS)

    Wang, D.-Q.; Hubbard, C.R.; Spooner, S.

    2000-01-01

    This paper will present a method and program to precisely calculate the coordinates in a positioner coordinate system from given sample position coordinates with a minimum number of neutron surface scans for three possible circumstances in stress and texture measurement using neutron diffraction

  12. Texture and neutron diffraction

    International Nuclear Information System (INIS)

    Szpunar, J.

    1976-01-01

    The neutron diffraction method has only recently become a tool for studying the structure of polycrystalline materials. There are some fields such as texture studies where this method offers several advantages over other more common methods. Texture is the main subject of the review. The current status of the theory or deformation and recrystallization texture is discussed briefly. Texture is then described with the aid of the ODF function. Finally, applications of the neutron diffraction method are discussed using several examples of textures measured in metals and in non-metallic materials. Other, less known applications of neutron diffraction are also given, e.g. in stress measurements. The neutron diffraction method is extremely useful for studying the texture of coarse-grained materials. This method provides information on the average texture in a large volume. This enables one to measure texture in the same specimen in which anisotropy of the physical roperties has been measured. Selected examples are provided in which correlations between elastic, plastic and magnetic properties of polycrystalline materials and their texture are pointed out. Texture was measured in all these cases using the neutron diffraction method. (author)

  13. Neutron diffraction and oxide research

    International Nuclear Information System (INIS)

    Hunter, B.; Howard, C.J.; Kennedy, B.J.

    1999-01-01

    Oxide compounds form a large class of interesting materials that have a diverse range of mechanical and electronic properties. This diversity and its commercial implications has had a significant impact on physics research. This is particularly evident in the fields of superconductivity magnetoresistivity and ferroelectricity, where discoveries in the last 15 years have given rise to significant shifts in research activities. Historically, oxides have been studied for many years, but it is only recently that significant effort has been diverted to the study of oxide materials for their application to mechanical and electronic devices. An important property of such materials is the atomic structure, for the determination of which diffraction techniques are ideally suited. Recent examples of structure determinations using neutron diffraction in oxide based systems are high temperature superconductors, where oxygen defects are a key factor. Here, neutron diffraction played a major role in determining the effect of oxygen on the superconducting properties. Similarly, neutron diffraction has enjoyed much success in the determination of the structures of the manganate based colossal magnetoresistive (CMR) materials. In both these cases the structure plays a pivotal role in determining theoretical models of the electronic properties. The neutron scattering group at ANSTO has investigated several oxide systems using neutron powder diffraction. Two such systems are presented in this paper; the zirconia-based materials that are used as engineering materials, and the perovskite-based oxides that include the well known cuprate superconductors and the manganate CMR materials

  14. Neutron diffraction on pulsed sources

    International Nuclear Information System (INIS)

    Aksenov, V.L.; Balagurov, A.M.

    2016-01-01

    The possibilities currently offered and major scientific problems solved by time-of-flight neutron diffraction are reviewed. The reasons for the rapid development of the method over the last two decades has been mainly the emergence of third generation pulsed sources with a MW time-averaged power and advances in neutron-optical devices and detector systems. The paper discusses some historical aspects of time-of-flight neutron diffraction and examines the contribution to this method by F.L.Shapiro whose 100th birth anniversary was celebrated in 2015. The state of the art with respect to neutron sources for studies on output beams is reviewed in a special section. [ru

  15. Phonons from neutron powder diffraction

    Science.gov (United States)

    Dimitrov, D. A.; Louca, D.; Röder, H.

    1999-09-01

    The spherically averaged structure function S(\\|q\\|) obtained from pulsed neutron powder diffraction contains both elastic and inelastic scattering via an integral over energy. The Fourier transformation of S(\\|q\\|) to real space, as is done in the pair density function (PDF) analysis, regularizes the data, i.e., it accentuates the diffuse scattering. We present a technique which enables the extraction of off-center (\\|q\\|≠0) phonon information from powder diffraction experiments by comparing the experimental PDF with theoretical calculations based on standard interatomic potentials and the crystal symmetry. This procedure [dynamics from powder diffraction] has been successfully implemented as demonstrated here for two systems, a simple metal fcc Ni and an ionic crystal CaF2. Although computationally intensive, this data analysis allows for a phonon based modeling of the PDF, and additionally provides off-center phonon information from neutron powder diffraction.

  16. Texture investigation by neutron diffraction

    International Nuclear Information System (INIS)

    Feldmann, K.

    1987-01-01

    In the conventional angle dispersive neutron diffraction a monochromatic neutron beam is used. The pole figures under investigation have to be scanned one after another. The commonly applied angle dispersive method is limited to the consideration of Bragg reflection being isolated in the diffraction pattern. The application of multidetectors or position sensitive detectors is discussed. In the neutron time-of-flight (TOF) diffraction a white pulsed neutron beam allows one to satisfy the Bragg law for all lattice spacing at a fixed scattering angle. The main charateristics of the TOF diffraction experiment are shortly outlined. In this method all non-forbidden Bragg reflections are recorded in one pattern simultaneously. The TOF technique is well-suited to study low symmetric or multiphased specimens, especially geological materials, requiring a large number of pole figures for mathematical texture analysis. Multidetector systems can be used to shorten the necessary time for experiments. The registration of all Bragg reflections of fixed scattering geometry is equivalent to the information of the inverse pole figure for the corresponding sample position. Having short exposition times this approach can be applied for in-situ investigations. The magnetic moments of neutrons can be used to study magnetic anisotropies in materials. Two different techniques are discussed

  17. Single-crystal neutron diffraction studies of hydrogen-bonded systems: Two recent examples from IPNS

    Energy Technology Data Exchange (ETDEWEB)

    Koetzle, Thomas F. [IPNS Division, Argonne National Laboratory, Argonne, IL 60439 (United States)], E-mail: tkoetzle@anl.gov; Piccoli, Paula M.B.; Schultz, Arthur J. [IPNS Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2009-02-21

    Beginning with work in the 1950s at the first generation of research reactors, studies of hydrogen-bonded systems have been a prime application for single-crystal neutron diffraction. The range of systems studied was extended in the 1960s and 1970s, with the advent of high flux reactor sources, and beginning around 1980 studies at pulsed neutron sources have made increasingly important contributions. Recently at the Argonne Intense Pulsed Neutron Source (IPNS), working with collaborators, we completed two studies of hydrogen-bonded systems that will serve to illustrate topics of current interest. In the first study, on andrographolide, an active diterpenoid natural product, our neutron diffraction results definitively characterize the hydrogen-bonding interactions. The second IPNS study is on tetraacetylethane (TAE), a {beta}-diketone enol system with a very short, strong intramolecular O-H...O hydrogen bond. At IPNS, we have determined the neutron crystal structure of TAE at five temperatures between 20 and 298 K to investigate changes in the structure with temperature and to probe for disorder. Despite the successes illustrated by the two examples presented here and by many other studies, at present applications of single-crystal neutron diffraction continue to be extremely flux limited and constrained by the requirement for mm-size crystals for many problems. These limitations are being addressed through the realization of powerful instruments at a new generation of pulsed neutron sources, including in the USA the TOPAZ and MaNDi single-crystal diffractometers that are under development at the Spallation Neutron Source (SNS)

  18. Single-crystal neutron diffraction studies of hydrogen-bonded systems: Two recent examples from IPNS

    Science.gov (United States)

    Koetzle, Thomas F.; Piccoli, Paula M. B.; Schultz, Arthur J.

    2009-02-01

    Beginning with work in the 1950s at the first generation of research reactors, studies of hydrogen-bonded systems have been a prime application for single-crystal neutron diffraction. The range of systems studied was extended in the 1960s and 1970s, with the advent of high flux reactor sources, and beginning around 1980 studies at pulsed neutron sources have made increasingly important contributions. Recently at the Argonne Intense Pulsed Neutron Source (IPNS), working with collaborators, we completed two studies of hydrogen-bonded systems that will serve to illustrate topics of current interest. In the first study, on andrographolide, an active diterpenoid natural product, our neutron diffraction results definitively characterize the hydrogen-bonding interactions. The second IPNS study is on tetraacetylethane (TAE), a β-diketone enol system with a very short, strong intramolecular O-H⋯O hydrogen bond. At IPNS, we have determined the neutron crystal structure of TAE at five temperatures between 20 and 298 K to investigate changes in the structure with temperature and to probe for disorder. Despite the successes illustrated by the two examples presented here and by many other studies, at present applications of single-crystal neutron diffraction continue to be extremely flux limited and constrained by the requirement for mm-size crystals for many problems. These limitations are being addressed through the realization of powerful instruments at a new generation of pulsed neutron sources, including in the USA the TOPAZ and MaNDi single-crystal diffractometers that are under development at the Spallation Neutron Source (SNS).

  19. Single-crystal neutron diffraction studies of hydrogen-bonded systems: Two recent examples from IPNS

    International Nuclear Information System (INIS)

    Koetzle, Thomas F.; Piccoli, Paula M.B.; Schultz, Arthur J.

    2009-01-01

    Beginning with work in the 1950s at the first generation of research reactors, studies of hydrogen-bonded systems have been a prime application for single-crystal neutron diffraction. The range of systems studied was extended in the 1960s and 1970s, with the advent of high flux reactor sources, and beginning around 1980 studies at pulsed neutron sources have made increasingly important contributions. Recently at the Argonne Intense Pulsed Neutron Source (IPNS), working with collaborators, we completed two studies of hydrogen-bonded systems that will serve to illustrate topics of current interest. In the first study, on andrographolide, an active diterpenoid natural product, our neutron diffraction results definitively characterize the hydrogen-bonding interactions. The second IPNS study is on tetraacetylethane (TAE), a β-diketone enol system with a very short, strong intramolecular O-H...O hydrogen bond. At IPNS, we have determined the neutron crystal structure of TAE at five temperatures between 20 and 298 K to investigate changes in the structure with temperature and to probe for disorder. Despite the successes illustrated by the two examples presented here and by many other studies, at present applications of single-crystal neutron diffraction continue to be extremely flux limited and constrained by the requirement for mm-size crystals for many problems. These limitations are being addressed through the realization of powerful instruments at a new generation of pulsed neutron sources, including in the USA the TOPAZ and MaNDi single-crystal diffractometers that are under development at the Spallation Neutron Source (SNS).

  20. Thermodynamic modelling and in-situ neutron diffraction investigation of the (Nd + Mg + Zn) system

    International Nuclear Information System (INIS)

    Zhu, Zhijun; Gharghouri, Michael A.; Pelton, Arthur D.

    2016-01-01

    Highlights: • All phase diagram and thermodynamic data critically assessed for the (Nd + Mg + Zn) system. • All phases described by optimised thermodynamic models. • In-situ neutron diffraction performed to identify phases and transition temperatures. • Assessments of other (RE + Mg + Zn) systems have been carried out simultaneously. • The final product is a thermodynamic database for multicomponent (Mg + RE + Zn) systems. - Abstract: All available phase diagram data for the (Nd + Mg + Zn) system were critically assessed. In-situ neutron diffraction (ND) experiments were performed on selected samples to identify phases and transition temperatures. A critical thermodynamic evaluation and optimization of the (Nd + Mg + Zn) system was carried out and model parameters for the thermodynamic properties of all phases were obtained. The phase transformation behaviour of selected samples was well resolved from the ND experiments and experimental values were used to refine the thermodynamic model parameters.

  1. Thermodynamic modelling and in-situ neutron diffraction investigation of the (Ce + Mg + Zn) system

    International Nuclear Information System (INIS)

    Zhu, Zhijun; Gharghouri, Michael A.; Medraj, Mamoun; Lee, Soo Yeol; Pelton, Arthur D.

    2016-01-01

    Highlights: • All phase diagram and thermodynamic data critically assessed for the (Ce + Mg + Zn) system. • All phases described by optimized thermodynamic models. • In-situ neutron diffraction performed to identify phases and transition temperatures. • Assessments of other (RE + Mg + Zn) systems have been carried out simultaneously. • The final product is a thermodynamic database for multicomponent (Mg + RE + Zn) systems. - Abstract: All available phase diagram data for the (Ce + Mg + Zn) system were critically assessed. In-situ neutron diffraction (ND) experiments were performed on selected samples to identify phases and transition temperatures. A critical thermodynamic evaluation and optimization of the (Ce + Mg + Zn) system were carried out and model parameters for the thermodynamic properties of all phases were obtained. The phase transformation behaviour of selected samples was well resolved from the ND experiments and experimental data were used to refine the thermodynamic model parameters.

  2. Dynamic diffraction of neutrons on perfect crystals

    International Nuclear Information System (INIS)

    Abov, Yu.G.; Tyulyusov, A.N.; Elyutin, N.O.

    2002-01-01

    Theory and experimental results are presented for the phenomena observed in the interaction of a thermal neutron beam with a regular periodic system of nuclei, which constitutes a perfect crystal. Recent studies in this field resulted in the appearance of new trends in the neutron optics, such as neutron interferometry and topography. High angular- and energy-resolution neutron crystal spectrometers were designed and manufactured for the investigation of small-angle and diffractive scattering. Passable new theoretical description of neutron dynamic diffraction and new experiments with neutron beams are discussed [ru

  3. Dynamic diffraction of neutrons on perfect crystals

    CERN Document Server

    Abov, Y G; Elyutin, N O

    2002-01-01

    Theory and experimental results are presented for the phenomena observed in the interaction of a thermal neutron beam with a regular periodic system of nuclei, which constitutes a perfect crystal. Recent studies in this field resulted in the appearance of new trends in the neutron optics, such as neutron interferometry and topography. High angular- and energy-resolution neutron crystal spectrometers were designed and manufactured for the investigation of small-angle and diffractive scattering. Passable new theoretical description of neutron dynamic diffraction and new experiments with neutron beams are discussed

  4. Magnetic investigations using neutron diffraction and neutron depolarization

    International Nuclear Information System (INIS)

    Yusuf, S.M.

    2015-01-01

    In this article, the basic principles of neutron diffraction and neutron depolarization are presented along with the results of some important magnetic materials. In particular, the recent results of the rare earth based high magnetocaloric effect materials, semi-Heusler spintronics alloys, molecular magnets, layered spin system, and core-shell type magnetic nanoparticles have been described. The usefulness of the neutron diffraction and neutron depolarization techniques to understand structural and magnetic properties is brought out. (author)

  5. Neutron diffraction tomography: a unique, 3D inspection technique for crystals using an intensifier TV system

    International Nuclear Information System (INIS)

    Davidson, J.B.; Case, A.L.

    1978-01-01

    The application of phosphor-intensifier-TV techniques to neutron topography and tomography of crystals is described. The older, analogous x-ray topography using wavelengths approximately 1.5A is widely used for surface inspection. However, the crystal must actually be cut in order to see diffraction anomalies beneath the surface. Because 1.5-A thermal neutrons are highly penetrating, much larger and thicker specimens can be used. Also, since neutrons have magnetic moments, they are diffracted by magnetic structures within crystals. In neutron volume topography, the entire crystal or a large part of it is irradiated, and the images obtained are superimposed reflections from the total volume. In neutron tomography (or section topography), a collimated beam irradiates a slice (0.5 to 10 mm) of the crystal. The diffracted image is a tomogram from this part only. A series of tomograms covering the crystal can be taken as the specimen is translated in steps across the narrow beam. Grains, voids, twinning, and other defects from regions down to 1 mm in size can be observed and isolated. Although at present poorer in resolution than the original neutron and film methods, the TV techniques are much faster and, in some cases, permit real-time viewing. Two camera systems are described: a counting camera having a 150 mm 6 Li-ZnS screen for low-intensity reflections which are integrated in a digital memory, and a 300-mm system using analog image storage. Topographs and tomograms of several crystals ranging in size from 4 mm to 80 mm are shown

  6. Neutron diffraction in materials science

    International Nuclear Information System (INIS)

    Howard, C.J.

    1996-01-01

    This article deals with applications of neutron diffraction in materials science. Most of the examples presented here involve the use of powder diffraction, which has been described earlier. In most of these, the Rietveld method has been used for neutron diffraction data, using the Rietveld method. This being an application which was largely pioneered at Lucas Heights. Examples involving single crystal diffraction and neutron polarization analysis are also included. Most of the examples are drawn from studies carried out at Lucas Heights where there is diffraction to the study of ceramics, and this will be reflected in the choice of examples to be considered here. (author)

  7. Neutron diffraction and Vitamin E

    Energy Technology Data Exchange (ETDEWEB)

    Harroun, T A; Marquardt, D; Katsaras, J; Atkinson, J, E-mail: tharroun@brocku.ca

    2010-11-01

    It is generally accepted that neutron diffraction from model membrane systems is an effective biophysical technique for determining membrane structure. Here we describe an example of how deuterium labelling can elucidate the location of specific membrane soluble molecules, including a brief discussion of the technique itself. We show that deuterium labelled {alpha}-tocopherol sits upright in the bilayer, as might be expected, but at very different locations within the bilayer, depending on the degree of lipid chain unsaturation.

  8. Neutron diffraction on a grating with monochromatic and polychromatic neutrons

    International Nuclear Information System (INIS)

    Baumann, J.; Kalus, J.

    1989-01-01

    Neutron diffraction experiments on a grating using monochromatic and polychromatic neutrons are described. The grating constant G was 60 μm. By the use of an achromatic system we were able to observe higher order diffraction maxima even with a wavelength spread of Δλ/λ=0.5. (orig.)

  9. Texture studies using neutron diffraction

    International Nuclear Information System (INIS)

    Szpunar, J.A.

    1984-01-01

    Various aspects of the application of neutron scattering methods to texture studies are reviewed. The neutron method is compared with other methods of texture measurement and techniques of neutron diffraction registration of texture are discussed. Examples are presented of the use of neutron scattering for texture examination in materials having various grain sizes and degrees of structural inhomogeneity. It is also demonstrated that the information about texture can be used in the discussion of the deformation and recrystallization processes in metals. Neutron diffraction results are shown to be helpful in the examination of the influence of texture on the anisotropy of physical properties in materials. The possibility of neutron diffraction measurements of magnetic texture is reported. Finally the accuracy of texture measurements using the neutron method is discussed. (author)

  10. Dynamical theory of neutron diffraction

    International Nuclear Information System (INIS)

    Sears, V.F.

    1978-01-01

    We present a review of the dynamical theory of neutron diffraction by macroscopic bodies which provides the theoretical basis for the study of neutron optics. We consider both the theory of dispersion, in which it is shown that the coherent wave in the medium satisfies a macroscopic one-body Schroedinger equation, and the theory of reflection, refraction, and diffraction in which the above equation is solved for a number of special cases of interest. The theory is illustrated with the help of experimental results obtained over the past 10 years by a number of new techniques such as neutron gravity refractometry. Pendelloesung interference, and neutron interferometry. (author)

  11. Neutron Powder Diffraction in Sweden

    International Nuclear Information System (INIS)

    Tellgren, R.

    1986-01-01

    Neutron powder diffraction in Sweden has developed around the research reactor R2 in Studsvik. The article describes this facility and presents a historical review of research results obtained. It also gives some ideas of plans for future development

  12. Pulsed neutron diffraction in special sample environments

    International Nuclear Information System (INIS)

    Jorgensen, J.D.

    1987-05-01

    Neutron diffraction is a powerful tool for structural studies of samples in special sample environments because of the high penetrating power of neutrons compared to x rays. The neutrons readily penetrate special sample containers, heat shields, pressure vessels, etc., making it unnecessary in most cases to compromise the effectiveness of the sample environment system by providing windows for the incident and scattered neutrons. Pulsed neutrons obtained from an accelerator-based pulsed neutron source offer the additional advantage that many diffraction experiments can be done at a single, fixed scattering angle by the time-of-flight technique. In the fixed-angle scattering geometry, shielding and collimation can be optimized in order to access the largest possible sample volume with neutrons while completely avoiding scattering from the surrounding sample vessel. Thus, the data are free from unwanted background scattering. In this paper, the basic principles of neutron diffraction in special sample environments are discussed and examples of apparatus used for neutron diffraction measurements at low temperature, high temperature, and high pressure are presented. 36 refs., 15 figs., 3 tabs

  13. Neutron diffraction studies of glasses

    International Nuclear Information System (INIS)

    Wright, A.C.

    1987-01-01

    A survey is given of the application of neutron diffraction to structural studies of oxide and halide glasses. As with crystalline materials, neutron and X-ray diffraction are the major structural probes for glasses and other amorphous solids, particularly in respect of intermediate range order. The glasses discussed mostly have structures which are dominated by a network in which the bonding is predominantly covalent. The examples discussed demonstrate the power of the neutron diffraction technique in the investigation of the structures of inorganic glasses. The best modern diffraction experiments are capable of providing accurate data with high real space resolution, which if used correctly, are an extremely fine filter for the various structural models proposed in the literature. 42 refs

  14. Neutron diffraction principles

    International Nuclear Information System (INIS)

    Granada, Jose R.

    1998-01-01

    Neutron as research element contributes at present to the understanding and development of almost all aspects related to basic and applied science, even with the relative inaccessibility of neutron sources and the fact that the most intense sources still provide relatively weak neutron beams. The initial discovery of these potentialities and the first works that allowed to convert the neutronic techniques into the actual powerful experimental tool, have been recognized by the adjudication of the Nobel Prize in Physics 1994 to Professors B. Brockhouse and C. Shull. Unfortunately, these tools have not been exploited neither in our country, nor in the Latin American area, with the exception of very limited applications in Materials Science. Although the theoretical principles of neutron scattering techniques have been treated in texts and review works, the aim of this work is to present a compact set of expressions, oriented to sustain and explain the basic forms or the most frequent use for the interpretation of experimental results. The formulation, mostly based on the initial chapters of the Ph.D. Thesis of G.J. Cuello (Instituto Balseiro, 1996), only considers nuclear scattering of neutrons for extension reasons, but it must be taken into account that the experiments designed for the study of the magnetic properties of materials currently play a rol of importance equal to those

  15. Diffraction and local order in amorphous systems. The case of thermal neutrons

    International Nuclear Information System (INIS)

    Tourand, G.

    1977-01-01

    Phenomenologically an amorphous material was defined as a system without any well-defined diffraction pattern. An attempt is made to give a more rigorous definition of the amorphous state. The pair distribution function g(r) will then be defined with respect to the structural properties, a knowledge of which is essential for a better understanding of amorphous systems. The information yielded by this function on the nature of the local order and its limitations due to the various approximations used will be discussed. The different experimental means available for obtaining the pair correlation function will be critically examined. Emphasis will be placed on thermal neutron measurements. Finally, how the function g(r) used as a local order parameter is deduced from the experimental data (diffuse intensity) [fr

  16. Diffraction-grating neutron interferometers

    International Nuclear Information System (INIS)

    Ioffe, A.I.

    1988-01-01

    Aberration distortions of wavefronts in a very cold neutron interferometer using diffraction gratings are analyzed. Aberrations that considerably reduce the efficiency of a two-grating interferometer are shown to be fully compensable by adding a third diffraction grating, which also permits the interferometer to operate with a non-collimated and non-monochromatized illuminating beam thereby raising its efficiency. A fourth diffraction grating additionally permits compensation of effects of the terrestrial rotation that affect performance of a large interferometer in which the spatial separation of beams can be of the order of a few meters. It is demonstrated to be practically possible to implement an interferometer for neutrons having a wavelength λ = 20 A and to use it in experiments aimed at finding the electric charge of the neutron at the level of 10 -23 to 10 -22 of the electronic charge. (orig.)

  17. Industrial applications of neutron diffraction

    International Nuclear Information System (INIS)

    Felcher, G.P.

    1989-01-01

    Neutron diffraction (or, to be more general, neutron scattering) is a most versatile and universal tool, which has been widely employed to probe the structure, the dynamics and the magnetism of condensed matter. Traditionally used for fundamental research in solid state physics, this technique more recently has been applied to problems of immediate industrial interest, as illustrated in examples covering the main fields of endeavour. 14 refs., 14 figs

  18. Neutron diffraction - instrument and experiment

    International Nuclear Information System (INIS)

    Siruguri, Vasudeva

    2010-01-01

    I describe the basic concepts that go into the design of a neutron diffractometer at a reactor source. Recent developments undertaken at our centre in this regard will be highlighted. Importance of sample environment to carry out front-line research problems with be emphasized. The Rietveld method used for neutron diffraction data analysis will be discussed in some detail along with a short introduction to magnetic refinement. (author)

  19. Texture determination by neutron diffraction

    International Nuclear Information System (INIS)

    Dervin, P.

    1981-02-01

    Application of neutron diffraction to crystallographic texture determination shows many advantages: possibility of an important grain size, the quantity of material contributing to diffraction is more important than with X rays, good accuracy and complete pole figures are obtained by transmission only eliminating corrections needed with X rays. Texture determination allows control and improvement of material quality. Texture studies give good informations on mechanisms occuring in deformation or recrystallization of polycrystals and on anisotropy of physical and mechanical properties [fr

  20. Neutron polarisers for diffraction experiments

    International Nuclear Information System (INIS)

    Cussen, L.D.; Goossens, D.J.; Hicks, T.J.

    2000-01-01

    Full text: Every neutron in a neutron beam has a spin which is either up or down. In an unpolarised beam, half the neutrons are up and half are down. A neutron polariser is a device which creates an imbalance in the number of up and down spin neutrons in the beam, thus giving a net beam polarisation. The three most common techniques for polarising neutron beams are supermirrors, Heusler alloy polarising monochromators and neutron spin filters. Supermirrors use the difference in refractive index for up and down spin neutrons at a magnetic/non-magnetic interface to selectively remove neutrons of one spin state from the beam. Heusler alloy polarisers give polarised beams through spin dependent Bragg reflection, and transmission filters work by preferentially absorbing the neutrons in one spin state. The most promising filter material is polarised gaseous 3 He, in which the lone neutron is polarised and then the atom will preferentially absorb a neutron of the opposite spin. All three techniques have different advantages. Here, we compare the three techniques by generating quality factors which relate closely to an instruments performance in an experiment and determining which polariser will give the best quality factor for a given type of experiment. We find that supermirrors give the best results when narrow angular divergence of the neutron beam is desired, while filters are best when short wavelengths and wide angular divergence is required. For a powder diffractometer, this implies that a supermirror would be used to polarise the incident beam, while a large array of supermirrors or a single curved transmission filter could be used to analyse the polarisation of the diffracted intensity. We note that while Heusler alloys have advantages in that they combine polarisation with monochromation, on purely performance based criteria, they are not competitive with supermirrors or well-developed transmission filter technology

  1. Neutron interferometers with diffraction gratings

    International Nuclear Information System (INIS)

    Ioffe, A.I.

    1983-01-01

    A neutron interferometer is described in which the amplitude coherent division of the wave fronts is realized by means of neutron diffraction gratings. Photolithographic gratings on glass with a rectangular surface relief profile with a 58 Ni sprayed layer 2000 A thick are used as gratings. In contrast to perfect-crystal neutron interferometers the designed interferometer is capable of operating in the longwave neutron spectrum region. Variation of the value of spatial division of the interfering beams (up to 50 cm) and rather a high efficiency of the amergent beam together with the elemination of neutron beam passage through the interferometer coherent divosor material in such an interferometer permit to use it for solving problems of the solid-state physics and nuclear physics, for example, foA searching for the Yang Mills long-range field

  2. Diffraction limit of the theory of multiple small-angle neutron scattering by a dense system of scatterers

    Science.gov (United States)

    Dzheparov, F. S.; Lvov, D. V.

    2016-02-01

    Multiple small-angle neutron scattering by a high-density system of inhomogeneities has been considered. A combined approach to the analysis of multiple small-angle neutron scattering has been proposed on the basis of the synthesis of the Zernike-Prince and Moliére formulas. This approach has been compared to the existing multiple small-angle neutron scattering theory based on the eikonal approximation. This comparison has shown that the results in the diffraction limit coincide, whereas differences exist in the refraction limit because the latter theory includes correlations between successive scattering events. It has been shown analytically that the existence of correlations in the spatial position of scatterers results in an increase in the number of unscattered neutrons. Thus, the narrowing of spectra of multiple small-angle neutron scattering observed experimentally and in numerical simulation has been explained.

  3. Neutron diffraction in a frustrated ferrite

    International Nuclear Information System (INIS)

    Mirebeau, I.; Iancu, G.; Gavoille, G.; Hubsch, J.

    1994-01-01

    The competition between a long range ordered ferrimagnetic lattice and small fluctuating clusters have been probed by neutron diffraction in a titanium magnesium frustrated ferrite. The description of the system is then compared to the predictions of several theoretical models for frustrated systems. 3 figs., 8 refs

  4. Neutron diffraction studies of thin film multilayer structures

    Energy Technology Data Exchange (ETDEWEB)

    Majkrzak, C.F.

    1985-01-01

    The application of neutron diffraction methods to the study of the microscopic chemical and magnetic structures of thin film multilayers is reviewed. Multilayer diffraction phenomena are described in general and in particular for the case in which one of the materials of a bilayer is ferromagnetic and the neutron beam polarized. Recent neutron diffraction measurements performed on some interesting multilayer systems are discussed. 70 refs., 5 figs.

  5. Neutron diffraction studies of thin film multilayer structures

    International Nuclear Information System (INIS)

    Majkrzak, C.F.

    1985-01-01

    The application of neutron diffraction methods to the study of the microscopic chemical and magnetic structures of thin film multilayers is reviewed. Multilayer diffraction phenomena are described in general and in particular for the case in which one of the materials of a bilayer is ferromagnetic and the neutron beam polarized. Recent neutron diffraction measurements performed on some interesting multilayer systems are discussed. 70 refs., 5 figs

  6. Neutron Diffraction and Inorganic Materials Discovery

    International Nuclear Information System (INIS)

    Rosseinsky, M.J.

    2005-01-01

    Full text: The discovery of complex inorganic materials is an important academic and technological challenge because of the opportunities these systems offer for observation of new phenomena, and the questions they pose for fundamental understanding. This presentation will illustrate the key role of neutron powder diffraction in enabling the discovery of new classes of materials, and in evaluating their properties and the conditions under which they need to be processed to optimise their behaviour in devices for applications. New chemistry is illustrated by the transition metal oxide hydrides, where both structure and ionic mobility required neutron scattering characterisation. The relationship between chemistry, structure and properties will be addressed by considering the difficulties in inducing superconductivity in analogues of magnesium diboride. The role of both neutron and X-ray diffraction in evaluating the processing of microwave dielectric ceramics will be highlighted, with the discovery of new phases shown to be a useful bonus in this type of in-situ study. (author)

  7. Neutron diffraction study of phase relationship of Ti-C-H system

    International Nuclear Information System (INIS)

    Khidirov, I.; Mukhtarova, N.N.; Mirzaev, B.B.; Serikbaev, B.T.; Zaginaichenko, S.Yu.; Schur, D.V.; Pishuk, V.K.; Kuzmenko, L.V.; Garbuz, V.V.; Nuzhda, S.V.; Pishuk, O.V.

    2006-01-01

    Full text: Due to such properties as high temperature of melting, solidity, stability in aggressive environments, etc., titanium carbide is widely used in modern techniques. It is necessary to know the phase relationships in Ti-C system for scientifically proved using. According to the phase diagram of Ti-C system, there are three phases in it: the solid solutions of carbon in the hexagonal lattice of α-Ti and in the body-centered cubic (BCC) lattice of β-Ti with rather limited solubility and also the face-centered cubic (FCC) titanium carbide TiC x with wide homogeneity range (TiC 0,32 / TiC 1,00 ). A number of the ordered phases was observed on the basis of FCC-phase. It is known, that even insignificant hydrogen impurity strongly influences at the phase relations in Ti-C system. At the same time because of specificity of some technologies of titanium carbide reception, it contains an impurity of hydrogen in its composition. However influence of hydrogen on phase relations of Ti-C system is not investigated enough. The aim of the work is to study hydrogen influence on the phase relations in Ti-C system by neutron (λ =1.085 A) and X-ray ( λ =1.5418 A) diffraction methods. Samples of TiC x H y (x = C/Ti, y H/Ti) were synthesized in the wide interval of carbon and hydrogen concentrations by sintering method from the powder of titanium of PTS trade-mark containing 0,35 mass % of hydrogen, by addition both of given quantity of TiH 2 and of soot of the trade-mark 'very pure'; the samples were studied by neutron and X-ray diffraction methods. Quartz ampoules with briquettes of the samples were pumped out up to vacuum of 1.33 10'-'4 Pa at the room temperature and were sintered in the furnace using the special regime selected by us. The briquettes were annealed from the temperature of 600 deg. C. As our experiments show, at this temperature the formation of Ti 2 C 1-x H 2-x solid solution and rapid absorption of hydrogen by this solution were observed. Also at this

  8. Magnetic structures: neutron diffraction studies

    International Nuclear Information System (INIS)

    Bouree-Vigneron, F.

    1990-01-01

    Neutron diffraction is often an unequivocal method for determining magnetic structures. Here we present some typical examples, stressing the sequence through experiments, data analysis, interpretation and modelisation. Two series of compounds are chosen: Tb Ni 2 Ge 2 and RBe 13 (R = Gd, Tb, Dy, Ho, Er). Depending on the nature of the elements, the magnetic structures produced can be commensurate, incommensurate or even show a transition between two such phases as a function of temperature. A model, taking magnetic exchange and anisotropy into account, will be presented in the case of commensurate-incommensurate magnetic transitions in RBe 13

  9. Neutron diffraction study of ilvaite

    International Nuclear Information System (INIS)

    Nobuhiko, Haga; Yoshio, Takeuchi

    1976-01-01

    The crystal structure of ilvaite (lievrite) has been investigated by means of neutron diffraction. The result of the investigation was the space group Pbnm. Of two nonequivalent octahedral positions, one is eightfold and the other fourfold, the former is occupied by Fe 3+ and Fe 2+ , and the latter by Fe 2+ . Mn is preferably distributed, substituting for Fe 2+ , over the fourfold position. The chemical formula for Mn-bearing ilvaite hence may best be expressed by Ca(Fe 3+ , Fe 2+ ) 2 (Fe 2+ , Mn)OSi 2 O 7 (OH). (orig./GSC) [de

  10. High efficiency moderator for pulsed neutron diffraction

    International Nuclear Information System (INIS)

    Mayer, R.E.; Granada, J.R.; Gillette, V.H.; Dawidowski, J.

    1990-01-01

    Moderators consisting of clusters of smaller slow-neutron-decoupled moderating elements were tested through experiments of pulsed neutron diffraction, leakage spectrum measurement, and neutron pulse decay. A simple slab and a thin 'sandwich' moderator were also measured for comparison purposes. For a given time width of the neutron pulse in the usual wavelength range for neutron diffraction, the proposed assembly produced a much higher neutron yield. Clues to the implementation of the desired time-response in moderator design and optimization are suggested by the present results. (orig.)

  11. Optimizing Crystal Volume for Neutron Diffraction

    Science.gov (United States)

    Snell, Edward H.; vanderWoerd, Mark; Damon, Michael; Judge, Russell, A.; Myles, Dean; Meilleur, F.

    2006-01-01

    Neutron diffraction is uniquely sensitive to hydrogen positions and protonation state. In that context structural information from neutron data is complementary to that provided through X-ray diffraction. However, there are practical obstacles to overcome in fully exploiting the potential of neutron diffraction, Le. low flux and weak scattering. Several approaches are available to overcome these obstacles and we have investigated the simplest: increasing the diffracting volume of the crystals. Volume is a quantifiable metric that is well suited for experiment design and optimization techniques. By using response surface methods we have optimized xylose isomerase crystal volume, enabling neutron diffraction while we determined the crystallization parameters with the minimum of experiments. Our results suggest a systematic means of enabling neutron diffraction studies for a larger number of samples that require information on hydrogen position and/or protonation state.

  12. High temperature X-ray and neutron diffraction studies on zirconium oxide systems

    International Nuclear Information System (INIS)

    Turner, D.R.

    1980-04-01

    High and room temperature X-ray powder diffraction studies have been made on the monoclinic and tetragonal forms of zirconium dioxide (zirconia). The formation of low temperature tetragonal zirconia from pure and doped zirconium hydroxides has been studied as has the formation of high temperature tetragonal zirconia from monoclinic zirconia. The thermal expansions of monoclinic and high temperature tetragonal zirconia have been measured at temperatures up to 1100 deg C for monoclinic and 1300 deg C for tetragonal zirconia. Neutron powder diffraction profile analysis has been performed on monoclinic zirconia using the PANDA diffractometer at AERE Harwell. Data were collected at liquid helium temperature, room temperature and at up to 800 deg C. The results confirm the thermal expansion results from the X-ray study. In addition, the changes with temperature in fractional atomic coordinates and cell parameters have been used to compute the changes in relative atomic positions and interpreted in accordance with a proposed mechanism for the monoclinic to tetragonal transformation. The major movement is that of the Osub(II) (3-coordinate) oxygen atom. (author)

  13. Present-day neutron diffraction at pulsed neutron sources

    International Nuclear Information System (INIS)

    Balagurov, A.M.

    1992-01-01

    The current status of neutron-diffraction experiments at pulsed neutron sources is described. The general problems in time-of-flight neutron-diffraction studies are discussed. High-resolution experiments on polycrystalline materials, structure analysis, and special experiments using single crystals are discussed, along with studies of transient processes of short duration. Special attention is paid to recent topics: very high-resolution diffractometry, neutron Fourier diffractometers, and real-time studies. 81 refs., 20 figs., 6 tabs

  14. Neutron diffraction texture analysis for industrial applications

    International Nuclear Information System (INIS)

    Brokmeier, H.G.

    1994-01-01

    Considering the high transmission of neutron radiation, neutron diffraction is an efficient tool for the analysis of various material parameters of bulk material in a non-destructive way. Industrial application of texture analysis by X-ray diffraction is well established, whereas neutron diffraction applications are seldom. Thus a brief description explains the main differences between X-ray and neutron diffraction regarding texture measurements such as the investigation of coarse-grained materials, of large sample volumes and of multi-phase materials. The investigation of average textures of large sample volumes allows directly a correlation to material properties (e.g. Young's modulus, electric conductivity, plastic deformability, strength), which were determined on a workpiece. Examples will be given to show some applications of neutron diffraction texture analysis for technological interests. (orig.)

  15. DNA hydration studied by neutron fiber diffraction

    International Nuclear Information System (INIS)

    Fuller, W.; Forsyth, V.T.; Mahendrasingam, A.; Langan, P.; Pigram, W.J.

    1994-01-01

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

  16. Parity-violation effects in neutron diffraction

    International Nuclear Information System (INIS)

    Zaretskii, D.F.; Sirotkin, V.K.

    1984-01-01

    The effects of parity violation in polarized-neutron diffraction by nuclei are considered. It is shown that the case of dynamical Laue diffraction exhibits significantly enhanced parity-violation effects, and that this enhancement is due to a pendulum-type dependence of the diffracted-beam intensity on the thickness. The effects are estimated for a number of nuclei in the case of thermal neutrons

  17. Structural materials evaluation by neutron diffraction method

    International Nuclear Information System (INIS)

    Suzuki, Hiroshi

    2010-01-01

    It is well known that neutron diffraction method enables us to measure residual stresses inside materials. It can also evaluate deformation behaviors and phase transformation of materials under loading at various environments such as high or low temperature and also evaluate microstructural factors such as dislocation density, cell size and texture by analyzing diffraction profile. This article reviews some topics of structural materials evaluation using neutron diffraction. (author)

  18. An introduction to neutron powder diffraction

    International Nuclear Information System (INIS)

    Kennedy, S.

    1999-01-01

    Full text: The aim of this presentation is to provide an introduction to neutron powder diffraction. The technique has developed from humble beginnings in the first generation of nuclear reactors in the late 1940's, to become one of the most widely used and productive forms of neutron beam research. Its popularity stems from the unique properties of thermal neutrons, which make them the ideal probe for obtaining spatial and dynamic information about atomic nuclei and magnetic dipoles in condensed matter. Neutron powder diffraction is particularly useful for location of lighter elements, in magnetic structure determination, for understanding thermal motions of atoms and for in-situ studies of materials at extreme temperatures and pressures. It is commonly used for research in condensed matter physics, structural chemistry and materials science at nuclear research reactors and spallation neutron sources around the world. The basic properties of thermal neutrons that are exploited in condensed matter research will be described. The neutron powder diffraction technique will be discussed with particular attention to comparisons with the X-ray powder diffraction technique, to which it is complementary. A brief description of the neutron powder diffraction facilities at ANSTO's HIFAR research reactor will be given, along with selected examples of neutron diffraction experiments that illustrate the power of the technique. Copyright (1999) Australian X-ray Analytical Association Inc

  19. In situ structural studies with neutron diffraction

    International Nuclear Information System (INIS)

    Laversenne, L.; Hansen, T.C.

    2015-01-01

    The authors present the features of neutron diffraction in terms of necessary neutron sources, diffusion contrast, penetration and magnetism. In situ diffraction experiments consist in recording the diffraction signal of a sample when this sample undergoes a monitored change in one of the following parameters: temperature (thermo-diffraction), pressure, magnetic or electric field or gaseous atmosphere. Most in situ diffraction experiments are performed on powders and they required a more or less complex equipment according to the parameter that varies. Examples and results of in situ neutron diffraction experiments are detailed in the article: -) the electrochemical loading of electrodes, -) the absorption of hydrogen for energy storage, -) the study of materials under high pressure which has allowed the investigation of phase diagrams when the inter-atomic distance varies, and -) the study of magnetism through thermo-diffraction. (A.C.)

  20. Report from the neutron diffraction work group

    International Nuclear Information System (INIS)

    1978-08-01

    This progress report of the neutron diffraction group at the Hahn Meitner Institute in Berlin comprises the following contributions: Three-dimensional critical properties of CsNiF 3 around the Neel point; Spin waves in CsNiF 3 with an applied magnetic field; Solitons in CsNiF 3 : Their experimental evidence and their thermodynamics; Neutron diffraction study of DAG at very low temperatures and in external magnetic field; Neutron diffraction investigation of tricritical behaviour in DyPO 4 ; Crystalline modifications and structural phase transitions of NaOH; Gitterdynamik von Cerhydrid; Investigation of the ferroelectric-ferroelastic phase transition in KH 2 PO 4 and RbH 2 PO 4 by means of γ-ray diffractometry; A γ-ray diffractometer for systematic measurements of absolute structure factors; Electron density in pyrite by combined γ-ray and neutron diffraction measurements: Thermal parameters from short wavelength neutron data; Accurate determination of temperature parameters from neutron diffraction data: Direct observation of the thermal diffuse scattering from silicon using perfect crystals; A Compton spectrometer for momentum density studies using 412 keV γ-radiation; Investigation of the electronic structure of Niobiumhydrides by means of gamma-ray Compton scattering; Interpretation of Compton profile data in position space; High resolution neutron scattering measurements on single crystals using a horizontally bent monochromator and a multidetecter; Statistical analysis of neutron diffraction studies of proteins. (orig.) [de

  1. Mechanochemical synthesis in the Li-Mg-N-D system under deuterium gas: a neutron diffraction study.

    Science.gov (United States)

    Li, Z; Zhang, J; Latroche, M; Wang, S; Jiang, L; Du, J; Cuevas, F

    2016-09-14

    The Mg(NH2)2/2LiH mixture is considered as one of the most valuable reversible hydrogen storage systems for feeding PEM fuel cells. In this paper, we investigate the mechanochemical synthesis in the Li-Mg-N-H system under deuterium gas, using Li3N and Mg as reactants, and the structural and sorption properties of the intermediate and final products mainly by means of neutron powder diffraction. Mechanochemistry leads to the end formation of amorphous Mg(ND2)2, which crystallizes upon heating above 425 K. During synthesis, a novel cation-mixed nitride/imide phase of simplified composition Li3MgN2D has been unveiled as the intermediate phase. It crystallizes in the cubic disordered anti-fluorite type structure (S.G. Fm3[combining macron]m) with a lattice parameter of 4.996 Å at room temperature. Deuterium absorption in this compound occurs through an original solid solution type mechanism ending with the imide compound β-Li2MgN2D2. The conjoint use of mechanochemistry under deuterium gas and in situ neutron diffraction techniques offers new avenues for better characterization of the efficient hydrogen storage materials. In particular, this work highlights the unexpected role of intermediate nitride/imide phases in the Li-Mg-N-H system.

  2. Conventional high pressure techniques fro neutron diffraction

    International Nuclear Information System (INIS)

    Mizuki, Jun-ichiro; Endoh, Yasuo

    1981-01-01

    Conventional high pressure techniques using a clamped type pressure cell have been adapted for studies by neutron diffraction. Careful calibration of the pressure sensing apparatus and an appropriate choice of pressure transmitting medium enable accurate neutron diffraction measurements to be made at reduced temperature as low as 4 K. In the present studies we have demonstrated that using the clamped type microbomb neutron diffraction measurements can be easily made under the pressure up to 5 kbar within the temperature range 4 K - 350 K. (author)

  3. Solving crystal structures from neutron diffraction data

    International Nuclear Information System (INIS)

    Wilson, C.C.

    1987-07-01

    In order to pursue crystal structure determination using neutron diffraction data, and given the wide experience available of solving structures using X-ray data, the codes used in X-ray structural analysis should be adapted to the different requirements of a neutron experiment. Modifications have been made to a direct methods program MITHRIL and to a Patterson methods program PATMET to incorporate into these the features of neutron rather than X-ray diffraction. While to date these modifications have been fairly straightforward and many sophistications remain to be exploited, results obtained from the neutron versions of both programs are promising. (author)

  4. Prospect for application of compact accelerator-based neutron source to neutron engineering diffraction

    Science.gov (United States)

    Ikeda, Yoshimasa; Taketani, Atsushi; Takamura, Masato; Sunaga, Hideyuki; Kumagai, Masayoshi; Oba, Yojiro; Otake, Yoshie; Suzuki, Hiroshi

    2016-10-01

    A compact accelerator-based neutron source has been lately discussed on engineering applications such as transmission imaging and small angle scattering as well as reflectometry. However, nobody considers using it for neutron diffraction experiment because of its low neutron flux. In this study, therefore, the neutron diffraction experiments are carried out using Riken Accelerator-driven Compact Neutron Source (RANS), to clarify the capability of the compact neutron source for neutron engineering diffraction. The diffraction pattern from a ferritic steel was successfully measured by suitable arrangement of the optical system to reduce the background noise, and it was confirmed that the recognizable diffraction pattern can be measured by a large sampling volume with 10 mm in cubic for an acceptable measurement time, i.e. 10 min. The minimum resolution of the 110 reflection for RANS is approximately 2.5% at 8 μs of the proton pulse width, which is insufficient to perform the strain measurement by neutron diffraction. The moderation time width at the wavelength corresponding to the 110 reflection is estimated to be approximately 30 μs, which is the most dominant factor to determine the resolution. Therefore, refinements of the moderator system to decrease the moderation time by decreasing a thickness of the moderator or by applying the decoupler system or application of the angular dispersive neutron diffraction technique are important to improve the resolution of the diffraction experiment using the compact neutron source. In contrast, the texture evolution due to plastic deformation was successfully observed by measuring a change in the diffraction peak intensity by RANS. Furthermore, the volume fraction of the austenitic phase in the dual phase mock specimen was also successfully evaluated by fitting the diffraction pattern using a Rietveld code. Consequently, RANS has been proved to be capable for neutron engineering diffraction aiming for the easy access

  5. Prospect for application of compact accelerator-based neutron source to neutron engineering diffraction

    International Nuclear Information System (INIS)

    Ikeda, Yoshimasa; Taketani, Atsushi; Takamura, Masato; Sunaga, Hideyuki; Kumagai, Masayoshi; Oba, Yojiro; Otake, Yoshie; Suzuki, Hiroshi

    2016-01-01

    A compact accelerator-based neutron source has been lately discussed on engineering applications such as transmission imaging and small angle scattering as well as reflectometry. However, nobody considers using it for neutron diffraction experiment because of its low neutron flux. In this study, therefore, the neutron diffraction experiments are carried out using Riken Accelerator-driven Compact Neutron Source (RANS), to clarify the capability of the compact neutron source for neutron engineering diffraction. The diffraction pattern from a ferritic steel was successfully measured by suitable arrangement of the optical system to reduce the background noise, and it was confirmed that the recognizable diffraction pattern can be measured by a large sampling volume with 10 mm in cubic for an acceptable measurement time, i.e. 10 min. The minimum resolution of the 110 reflection for RANS is approximately 2.5% at 8 μs of the proton pulse width, which is insufficient to perform the strain measurement by neutron diffraction. The moderation time width at the wavelength corresponding to the 110 reflection is estimated to be approximately 30 μs, which is the most dominant factor to determine the resolution. Therefore, refinements of the moderator system to decrease the moderation time by decreasing a thickness of the moderator or by applying the decoupler system or application of the angular dispersive neutron diffraction technique are important to improve the resolution of the diffraction experiment using the compact neutron source. In contrast, the texture evolution due to plastic deformation was successfully observed by measuring a change in the diffraction peak intensity by RANS. Furthermore, the volume fraction of the austenitic phase in the dual phase mock specimen was also successfully evaluated by fitting the diffraction pattern using a Rietveld code. Consequently, RANS has been proved to be capable for neutron engineering diffraction aiming for the easy access

  6. An adjustable diaphragm/collimator for neutron diffraction experiments

    International Nuclear Information System (INIS)

    Simms, P.

    1981-01-01

    In single-crystal neutron diffraction experiments, the environment surrounding the specimen may produce unwanted scattering and this should be limited by a system of simple but easily adjustable diaphragms. Here a system is described which has been fitted to a number of neutron diffractometers at the Institut Laue-Langevin at Grenoble. (Auth.)

  7. Time-resolved Neutron Powder Diffraction

    International Nuclear Information System (INIS)

    Pannetier, J.

    1986-01-01

    The use of a high-flux neutron source together with a large position sensitive detector (PSD) allows a powder diffraction pattern to be recorded at a time-scale of a few minutes so that crystalline systems under non-equilibrium conditions may now conveniently be investigated. This introduces a new dimension into powder diffraction (the time and transient phenomena like heterogeneous chemical reactions can now be easily studied. The instrumental parameters relevant for the design of such time-dependent experiments are briefly surveyed and the current limits of the method are discussed. The applications are illustrated by two kinds of experiment in the field of inorganic solid state chemistry: true kinetic studies of heterogeneous chemical reactions and thermodiffractometry experiments

  8. Feasibility study neutron diffraction at IRI

    Energy Technology Data Exchange (ETDEWEB)

    Haan, V.O. de

    1995-06-01

    Although neutron diffraction is a basic and relatively simple technique and should be available at a neutron source, it is not possible to perform neutron diffraction measurements at IRI at this moment. Until recently a neutron diffractometer with a relatively small flux at the sample position and a relaxed resolution (designed for liquid diffraction) was operated at IRI. Due to the modest neutron source intensity and the relatively old design (flat monochromator and single detector) this diffractometer was outdated. However, at a contemporary reactor source an instrument to perform neutron diffraction experiments cannot be missed. This study shows that thanks to recent developments in neutron diffraction optics it is possible to increase the flux, to enhance the resolution and to get a better flexibility. If also the number of detectors is increased or a position-sensitive detector is used to performance can be increased at least a thousand fold. A preliminary design is given to indicate how this gain can be realized. (orig.).

  9. Neutron forward diffraction by single crystal prisms

    Indian Academy of Sciences (India)

    November 2008 physics pp. 1109–1114. Neutron forward diffraction by single crystal prisms. SOHRAB ABBAS1,∗, APOORVA G WAGH1, MARKUS STROBL2 and. WOLFGANG ... vicinity of a Bragg reflection, the neutron deflection deviates sharply from that for an ... Bragg reflection, for several single crystal prisms.

  10. Neutron forward diffraction by single crystal prisms

    Indian Academy of Sciences (India)

    Abstract. We have derived analytic expressions for the deflection as well as transmitted fraction of monochromatic neutrons forward diffracted by a single crystal prism. In the vicinity of a Bragg reflection, the neutron deflection deviates sharply from that for an amorphous prism, exhibiting three orders of magnitude greater ...

  11. Neutron forward diffraction by single crystal prisms

    Indian Academy of Sciences (India)

    We have derived analytic expressions for the deflection as well as transmitted fraction of monochromatic neutrons forward diffracted by a single crystal prism. In the vicinity of a Bragg reflection, the neutron deflection deviates sharply from that for an amorphous prism, exhibiting three orders of magnitude greater sensitivity to ...

  12. Applications of the Fresnel diffraction of neutrons

    International Nuclear Information System (INIS)

    Klein, A.G.; Opat, G.I.

    1978-01-01

    The place of Fresnel diffraction in the overall scheme of neutron interference experiments is outlined and possible applications are discussed in the areas of: magnetic domain visualisation; measurement of nuclear scattering lengths with very small specimens; focussing of long wavelength neutron beams using zone plates

  13. Neutron forward diffraction by single crystal prisms

    International Nuclear Information System (INIS)

    Abbas, Sohrab; Wagh, Apoorva G.; Strobl, Markus; Treimer, Wolfgang

    2008-01-01

    We have derived analytic expressions for the deflection as well as transmitted fraction of monochromatic neutrons forward diffracted by a single crystal prism. In the vicinity of a Bragg reflection, the neutron deflection deviates sharply from that for an amorphous prism, exhibiting three orders of magnitude greater sensitivity to the incidence angle. We have measured the variation of neutron deflection and transmission across a Bragg reflection, for several single crystal prisms. The results agree well with theory. (author)

  14. Neutron Reflectivity and Grazing Angle Diffraction

    OpenAIRE

    Ankner, J. F.; Majkrzak, C. F.; Satija, S. K.

    1993-01-01

    Over the last 10 years, neutron reflectivity has emerged as a powerful technique for the investigation of surface and interfacial phenomena in many different fields. In this paper, a short review of some of the work on neutron reflectivity and grazing-angle diffraction as well as a description of the current and planned neutron rcflectometers at NIST is presented. Specific examples of the characterization of magnetic, superconducting, and polymeric surfaces and interfaces are included.

  15. Neutron Reflectivity and Grazing Angle Diffraction.

    Science.gov (United States)

    Ankner, J F; Majkrzak, C F; Satija, S K

    1993-01-01

    Over the last 10 years, neutron reflectivity has emerged as a powerful technique for the investigation of surface and interfacial phenomena in many different fields. In this paper, a short review of some of the work on neutron reflectivity and grazing-angle diffraction as well as a description of the current and planned neutron rcflectometers at NIST is presented. Specific examples of the characterization of magnetic, superconducting, and polymeric surfaces and interfaces are included.

  16. Diffraction in neutron imaging-A review

    Science.gov (United States)

    Woracek, Robin; Santisteban, Javier; Fedrigo, Anna; Strobl, Markus

    2018-01-01

    Neutron imaging is a highly successful experimental technique ever since adequate neutron sources were available. In general, neutron imaging is performed with a wide wavelength spectrum for best flux conditions in transmission geometry. Neutrons provide outstanding features in the penetration of many structural materials, which often makes them more suited for bulk sample studies than other forms of radiation, often in particular as they are also highly sensitive to some light elements, especially Hydrogen. In contrast to neutron scattering applications, imaging resolves macroscopic structures, nowadays down to, in the best case, below 10 micrometre, directly in real space. However, since more than a decade there is a growing number of techniques and applications in neutron imaging that - supported by powerful neutron sources - are taking advantage of wavelength resolved measurements. In this review we summarize and discuss this outstanding development and how wavelength resolved transmission neutron imaging is successfully exploiting diffraction mechanisms to access crystal structure information in the Angstrom regime, which conventionally is probed in reciprocal space by diffraction techniques. In particular the combination of information gained in real space and on crystallographic length scales makes this neutron imaging technique a valuable tool for a wide range of new applications, while it also qualifies neutron imaging to fully profit from the new generation of powerful pulsed neutron sources.

  17. Bragg diffraction optics in neutron diffractometry

    Czech Academy of Sciences Publication Activity Database

    Mikula, Pavol; Kulda, Jiří; Lukáš, Petr; Ono, M.; Šaroun, Jan; Vrána, Miroslav; Wagner, Vladimír

    2000-01-01

    Roč. 283, - (2000), s. 289-294 ISSN 0921-4526 R&D Projects: GA ČR GV202/97/K038 Institutional research plan: CEZ:AV0Z1048901 Keywords : neutron diffraction * bragg diffraction * focusing Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.893, year: 2000

  18. Neutron diffraction studies of amorphous solids

    International Nuclear Information System (INIS)

    Wright, A.C.

    1983-01-01

    A brief survey is presented of the role of neutron diffraction in structural studies of amorphous solids. The inherent limitations of the diffraction technique are discussed, together with modern instrumentation and methods for separating individual component correlation functions. An introduction is given to the use of modelling and the extraction of structural parameters from experimental data. (author)

  19. A High Pressure Apparatus for Neutron Diffraction

    OpenAIRE

    Kazuo, Kamigaki; Hajime, Yoshida; Masayoshi, Ohashi; Takejiro, Kaneko; Kozaburo, Sato; The Research Institute for Iron, Steel and Other Metals; The Research Institute for Iron, Steel and Other Metals; The Research Institute for Iron, Steel and Other Metals; The Research Institute for Iron, Steel and Other Metals; Department of Physics, Faculty of Science, Hirosaki University

    1980-01-01

    A high pressure apparatus was developed for thermal neutron diffraction of time-of-flight method. The high pressure vessel was a piston-cylinder type, and Ti-Zr alloy was used as a material of the cylinder. The coherent scattering of neutron is suppressed in Ti-53wt% Zr alloy. The diffraction spectrum is formed of peaks from the specimen and a background, which corresponds to the energy distribution of the incident neutron. High pressure measurements were made in RbBr on the transformation be...

  20. Neutron diffraction study of electrochemically synthesized djerfisherite

    International Nuclear Information System (INIS)

    Tani, B.; Mrazek, F.; Faber, J.; Hitterman, R.

    1986-01-01

    The electrochemical synthesis of a synthetic form of the mineral djerfisherite produced sufficient material (4g) for neutron powder diffraction analysis. The data were collected on the time-of-flight neutron diffractometer at the Intense Pulsed Neutron Source Facility at Argonne National Laboratory. A crystallographic refinement of the neutron diffraction data by the Rietveld analysis technique showed an improvement in the atom coordinate positions by a factor of ten over prior x-ray powder diffraction data. In addition, the refinement indicates 23 iron atoms randomly distributed about 24 available sites such that the formula of the synthetic form of djerfisherite can be expressed as K/sub 6/LiFe/sub 23/S/sub 26/Cl

  1. The phase problem in neutron diffraction

    International Nuclear Information System (INIS)

    Sikka, S.K.

    1983-01-01

    The structure of any crystal can now be determined ab initio from the neutron Bragg intensity data alone, without recourse to the x-ray structural analysis. This has been made possible by the reduction in data collection times due to the availability of increased neutron fluxes at the samples and the extensive development of the phase determining procedures for neutron diffraction in the last 15 years. In this review, the applications of direct methods, anomalous dispersion techniques and difference Patterson methods are reviewed and it is discussed why these methods are applicable in neutron diffraction. Their limitations are also discussed. Some newer methods like resonance-modulated diffraction and use of 'Renninger effect' to measure the structure invariants are also touched upon. (author)

  2. Magnetic correlations in oxides: neutron diffraction and neutron depolarization study

    International Nuclear Information System (INIS)

    Yusuf, S.M.

    2008-01-01

    We have studied magnetic correlations in several oxide materials that belong to colossal magnetoresistive, naturally occurring layered oxide showing low-dimensional magnetic ordering, solid oxide fuel cell interconnect materials, and magnetic nanoparticles using neutron diffraction and neutron depolarization techniques. In this paper, an overview of some of these results is given. (author)

  3. Quantitative phase analysis by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang Hee; Song, Su Ho; Lee, Jin Ho; Shim, Hae Seop [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-06-01

    This study is to apply quantitative phase analysis (QPA) by neutron diffraction to the round robin samples provided by the International Union of Crystallography(IUCr). We measured neutron diffraction patterns for mixed samples which have several different weight percentages and their unique characteristic features. Neutron diffraction method has been known to be superior to its complementary methods such as X-ray or Synchrotron, but it is still accepted as highly reliable under limited conditions or samples. Neutron diffraction has strong capability especially on oxides due to its scattering cross-section of the oxygen and it can become a more strong tool for analysis on the industrial materials with this quantitative phase analysis techniques. By doing this study, we hope not only to do one of instrument performance tests on our HRPD but also to improve our ability on the analysis of neutron diffraction data by comparing our QPA results with others from any advanced reactor facilities. 14 refs., 4 figs., 6 tabs. (Author)

  4. Front lines of structural analyses by pulsed Neutron Diffraction

    International Nuclear Information System (INIS)

    Shamoto, Shin-ichi; Kodama, Katsuaki; Suzuya, Kentaro; Kamiyama, Takashi; Otomo, Toshiya; Fukunaga, Toshiharu

    2008-01-01

    The neutron is a subatomic particle without electronic charge, but has a magnetic moment. This nature leads high permeability compared to x-rays, and therefore neutrons become the powerful nondestructive probe for measurements. Diffraction patterns for wide reciprocal space can be measured by pulsed neutrons, which have been exploited for the structural analyses from amorphous materials to crystalline solids. Further, the pulsed neutrons have been applied to the structural studies of highly disordered materials, and also nanometer size materials. The structural studies using pulsed neutrons are reviewed in this paper from pioneering researches to the latest results in comparison with those by synchrotron radiation x-rays. For the amorphous hydrogen storage material, TbFe 2 D 3.0 , the structure factor and atomic pair distribution function (PDF) by neutron diffraction are compared with those by x-ray diffraction. The local crystal structure of a multiferroic system has been studied by means of PDF analysis on neutron powder diffraction data. PDF analysis is employed in order to determine the precise lattice parameters of nano-structure materials. The three distinctive neutron diffractometers, super high resolution powder diffractometer, high intensity total diffractometer and iMATERIA (IBARAKI materials design diffractometer), under construction at Material and Life Science Facility in J-PARC are introduced. (Y.K.)

  5. Measurement of neutron diffraction with compact neutron source RANS

    Science.gov (United States)

    Ikeda, Y.; Takamura, M.; Taketani, A.; Sunaga, H.; Otake, Y.; Suzuki, H.; Kumagai, M.; Oba, Y.; Hama, T.

    2016-11-01

    Diffraction is used as a measurement technique for crystal structure. X-rays or electron beam with wavelength that is close to the lattice constant of the crystal is often used for the measurement. They have sensitivity in surface (0.01mm) of heavy metals due to the mean free path for heavy ions. Neutron diffraction has the probe of the internal structure of the heavy metals because it has a longer mean free path than that of the X-rays or the electrons. However, the neutron diffraction measurement is not widely used because large facilities are required in the many neutron sources. RANS (Riken Accelerator-driven Compact Neutron Source) is developed as a neutron source which is usable easily in laboratories and factories. In RANS, fast neutrons are generated by 7MeV protons colliding on a Be target. Some fast neutrons are moderated with polyethylene to thermal neutrons. The thermal neutrons of 10meV which have wavelength of 10nm can be used for the diffraction measurement. In this study, the texture evolution in steels was measured with RANS and the validity of the compact neutron source was proved. The texture of IF steel sheets with the thickness of 1.0mm was measured with 10minutes run. The resolution is 2% and is enough to analyze a evolution in texture due to compression/tensile deformation or a volume fraction of two phases in the steel sample. These results have proven the possibility to use compact neutron source for the analysis of mesoscopic structure of metallic materials.

  6. Residual stress measurement by neutron diffraction

    International Nuclear Information System (INIS)

    Akita, Koichi; Suzuki, Hiroshi

    2010-01-01

    Neutron diffraction method has great advantages, allowing us to determine the residual stress deep present within the bulk materials and components nondestructively. Therefore, the method has been applied to confirm the structural integrity of the actual mechanical components and structures and to improve the manufacturing process and strength reliability of the products. This article reviews the residual stress measurement methodology of neutron diffraction. It also refers to the appropriate treatments of diffraction plane, stress-free lattice spacing, coarse grain and surface error to obtain reliable results. Finally, a few applications are introduced to show the capabilities of the neutron stress measurement method for the studies on the strength and elasto-plastic behaviors of crystalline materials. (author)

  7. High-temperature chamber for study of neutron diffraction

    International Nuclear Information System (INIS)

    Gavrilenko, M.V.; Dvoeglazov, A.M.

    1992-01-01

    Design of a chamber designed to study neutron diffraction within 20-100 deg C temperature range, where the principle of specimen heating via electron bombardment is used, is described. Diameters of the screen and of the cover are selected so, that neutrons scattered at their walls can not be seen by the diffractometer regulating system. Absence of distortions of diffraction maxima within statistic error limits is pointed out. Intensities of diffraction maxima at setting of heater, screen and cover are not practically observed. There is no essential increase of background at chamber setting. Simplicity the design and long service life of the chamber is stressed

  8. Neutron diffraction studies of silicate glasses

    International Nuclear Information System (INIS)

    Urnes, S.; Herstad, O.

    1978-01-01

    The different ratios between the scattering amplitudes of X-rays and neutrons for various atomic constituents of glasses have been utilized to study the atomic ordering in silicate glasses. A comparison of corresponding atomic radial distribution curves obtained from neutron diffraction and electron radial distribution curves obtained with X-rays is made. The interatomic distances derived from the two methods are discussed. (Auth.)

  9. Optimizing Crystal Volume for Neutron Diffraction Studies

    Science.gov (United States)

    Snell, E. H.

    2003-01-01

    For structural studies with neutron diffraction more intense neutron sources, improved sensitivity detector and larger volume crystals are all means by which the science is being advanced to enable studies on a wider range of samples. We have chosen a simplistic approach using a well understood crystallization method, with minimal amounts of sample and using design of experiment techniques to maximize the crystal volume all for minimum effort. Examples of the application are given.

  10. Bragg diffraction optics in neutron diffractometry

    International Nuclear Information System (INIS)

    Mikula, Pavol; Vrana, Miroslav; Furusaka, Michihiro; Wagner, Volker; Choi, Yong-Nam; Moon, Myung-Kook; Em, Vjaceslav; Lee, Chang-Hee

    2004-01-01

    A review of recent practical applications of Bragg diffraction optics in neutron diffractometry is presented. Besides examples of a direct comparison of the flat Ge-mosaic and a bent perfect Si crystals for neutron monochromatization, the results of new tests of dispersive monochromator, multiple reflection monochromator and curved TOF analyzer for high- and ultra-high resolution studies as received within a wide collaboration are introduced

  11. Current advances in neutron diffraction stress measurement

    International Nuclear Information System (INIS)

    Suzuki, Hiroshi; Tomota, Yo

    2007-01-01

    Neutron diffraction has been employed for stress evaluation of various mechanical components. The hkl lattice plane spacings in a diffraction gauge volume are measured, then elastic strains are calculated and finally stresses are determined by using the Hooke's law. Since the real engineering mechanical parts are so complicated that more sophisticated method must be progressed to obtain stress distribution in the inside of a sample. Current advances on this issue are reviewed. (author)

  12. New moderator for pulsed neutron diffraction

    International Nuclear Information System (INIS)

    Mayer, R.E.; Granada, J.R.; Gillette, V.H.; Dawidowski, J.

    1989-01-01

    Experiments of neutron diffraction, leakage spectrum and pulse decay have been carried out on a new geometry, heterogeneously poisoned, set of moderators and on conventional sandwich and slab moderators for comparison purposes. For a given time pulse width, great increase in neutron leakage intensity has been found in these assemblies, up to 2.7 times that of a sandwich moderator. Clues to implementation of desired time-response in moderator design and of further increases in neutron yields are suggested by present results. 8 refs., 4 figs., 1 tab

  13. Applied neutron diffraction for industry (ANDI)

    Science.gov (United States)

    Rogge, R. B.; Root, J. H.; Donaberger, R. L.

    2006-11-01

    In general diffraction is a powerful technique for gaining an understanding of the behavior of materials. When combined with the high penetration of neutrons one has access to a uniquely powerful and nondestructive probe that has gained wide use in the materials science and engineering field. It is also true that neutrons provide an excellent tool for evaluating and verifying real industrial processes and/or fabrication routes. This paper focuses on examples in which neutrons have been put to work for industry; simulating realistic conditions, contributing to failure analysis, verifying the effectiveness of processing steps, and dealing with regulatory bodies.

  14. Applied neutron diffraction for industry (ANDI)

    International Nuclear Information System (INIS)

    Rogge, R.B.; Root, J.H.; Donaberger, R.L.

    2006-01-01

    In general diffraction is a powerful technique for gaining an understanding of the behavior of materials. When combined with the high penetration of neutrons one has access to a uniquely powerful and nondestructive probe that has gained wide use in the materials science and engineering field. It is also true that neutrons provide an excellent tool for evaluating and verifying real industrial processes and/or fabrication routes. This paper focuses on examples in which neutrons have been put to work for industry; simulating realistic conditions, contributing to failure analysis, verifying the effectiveness of processing steps, and dealing with regulatory bodies

  15. Physical bases of magnetic neutron diffraction

    International Nuclear Information System (INIS)

    Izyumov, Yu.A.

    1997-01-01

    The paper is a review of the authors work on use of the symmetry theory in neutron diffraction analysis of magnetic structures. A magnetic structure to be describe in terms of mixing coefficients for irreducible representations basis functions of the crystal space group. An algorithm given for determination of the wave vector and the atomic magnetic moments orientations of a crystal via determination of the mixing coefficients. Symmetry aspects of polarized neutrons are studied, particular dependence of magnetic scattering cross section on polarization of the neutron beam and change the polarization vector of the scattering beam

  16. Neutron diffraction from lead germanate glasses

    International Nuclear Information System (INIS)

    Umesaki, Norimasa; Brunier, T.M.; Wright, A.C.; Hannon, A.C.; Scinclair, R.N.

    1993-01-01

    High resolution neutron diffraction data have been collected on the PbO-GeO 2 glasses and on GeO 2 for comparison. These neutron data have revealed the existence of 6-fold coordinated germanium (GeO 6 octahedra) by virtue of the shift in the first peak in the obtained total correlation function T(r) and increase in the coordination. The neutron results also indicate that PbO exits as PbO 4 pyramids, as found in the orthorhombic form of PbO crystal, in the studied PbO-GeO 2 glasses. (author)

  17. Neutron diffraction analysis of materials featuring the perovskite structure

    International Nuclear Information System (INIS)

    Vratislav, S.

    1993-01-01

    The author's achievements in the title field are summarized and discussed. The dissertation is divided into 2 basic sections: state of the art in neutron diffraction of perovskite structure materials (the perovskite structure and its modifications, characterization of high-temperature superconductor structures, perovskites with magnetic ions, neutron diffraction in materials science), and experimental results concerning the structure of high-temperature superconductors (the Y-Ba-Cu-O system and the Bi-Sr-Ca-Cu-O system) and magnetic structures (the Pr-Ca-Mn-O system and the Pr-Sr-Mn-O system). Reprints of the author's relevant publications are included. (P.A.)

  18. Neutron Powder Diffraction and Constrained Refinement

    DEFF Research Database (Denmark)

    Pawley, G. S.; Mackenzie, Gordon A.; Dietrich, O. W.

    1977-01-01

    The first use of a new program, EDINP, is reported. This program allows the constrained refinement of molecules in a crystal structure with neutron diffraction powder data. The structures of p-C6F4Br2 and p-C6F4I2 are determined by packing considerations and then refined with EDINP. Refinement...

  19. A high pressure apparatus for neutron diffraction

    International Nuclear Information System (INIS)

    Kamigaki, Kazuo; Yoshida, Hajime; Ohashi, Masayoshi; Kaneko, Takejiro; Sato, Kozaburo.

    1980-01-01

    A high pressure apparatus was developed for thermal neutron diffraction of time-of-flight method. The high pressure vessel was a piston-cylinder type, and Ti-Zr alloy was used as a material of the cylinder. The coherent scattering of neutron is suppressed in Ti-53wt% Zr alloy. The diffraction spectrum is formed of peaks from the specimen and a background, which corresponds to the energy distribution of the incident neutron. High pressure measurements were made in RbBr on the transformation between NaCl-type structure and CsCl-type to a pressure about 20 kb, and a good agreement was confirmed with former experiments. (author)

  20. Pulsed Neutron Powder Diffraction for Materials Science

    International Nuclear Information System (INIS)

    Kamiyama, T.

    2008-01-01

    funded by Ibaraki prefecture for the promotion of new industries based on advanced science and technologies. It is for the first time in neutron facilities in Japan that a prefecture owns neutron instruments as well as neutron beam will be provided widely to industrial users. To make it successful, the user system is quite important because those users are expected to use IPD like chemical analyzers in their materials development process. Based on questionnaire data to several hundreds industries, IPD is designed as a versatile diffractometer including texture measurement, small angle scattering and total scattering as well as usual powder diffraction. IPD covers d range 0.15 -1 -1 to be utilized for varieties of structures: local structure, nano structure and crystal structure analyses. Typical measuring time for the typical 'Rietveld-quality' data is several minutes with the sample size of laboratory X-ray: 0.4 cc. SHRPD is designed to be the world highest resolution with Δd/d = 0.03% without sacrificing intensity. The combination of the high quality data from HRPD and their high-precision analysis gives us information on tiny structural changes which have been overlooked. After careful examination with the moderator group five years ago, we have decided to develop a high-resolution and good S/N moderator to achieve the 0.03% resolution within 100 m flight path. This development was almost successful up to now. Instrumental simulation and radiation analysis were almost completed. The d range 0.5< d(A)<4 with Δd/d = 0.03%, and covers 4< d(A)<45 with gradually changing resolution. Takumi is the first priority instrument in JAEA for stress mapping inside structure materials with the highest resolution of Δd/d = 0.2% (corresponding to 10∼5 to 10∼6 strain precision). The typical gauge volume will be 1 mm3. JED has transmission radiography detectors to support stress mapping. Software group is planning so that basic software to cover data acquisition and data

  1. Characteristics of neutron beam for prompt gamma neutron activation analysis diffracted by pyrolytic graphite monochromator

    International Nuclear Information System (INIS)

    Jun, Byung-Jin; Seong, Baek-Seok; Kim, Myung-Seop; Byun, Soo-Hyun; Choi, Hee-Dong

    1999-01-01

    As a method to obtain high thermal neutron flux with low background for a prompt gamma neutron activation analysis (PGAA) system which will be constructed at HANARO, a 30 MW research reactor in Korea Atomic Energy Research Institute, diffraction of a spare white beam before any filtering is adopted. The PGAA system will use a thermal neutron beam diffracted vertically by pyrolytic graphite (PG) crystals with the mosaic spread of 0.8 degree at near the surface of reactor biological shield. The ratio of diffracted beam flux to white beam is determined by the integrated reflectivity of the monochromator. To estimated neutron flux after diffraction, convolution of the incident beam divergence and crystal mosaicity is simulated using the Monte Carlo method. If the beam is focussed by the bent PGs, the expected flux at the sample position is about 3 x 10 8 n/cm 2 -s which is about 4% of white beam flux. The characteristics of neutron beam diffracted by the PG are investigated experimentally to confirm the neuron flux and its profile at the PGAA system. The comparative experiment is performed in the CN horizontal beam line of HANARO. Diffracted spectra with the Bragg angles of 22.5 and 45 degree are measured by using time-of-flight spectrometer and fluxes before and after diffraction are determined by gold-wire activation. The theoretical estimation agrees with the experimental verification with in 20%. (author)

  2. Anomalous neutron diffraction studies of disordered materials

    International Nuclear Information System (INIS)

    Sinclair, R.N.

    1993-01-01

    Large variations in the bound coherent scattering length for slow neutrons occur close to low energy neutron resonances for a small proportion of nuclei, offering the possibility for determination of partial correlation functions by carrying out diffraction experiments at neutron wavelengths which sample this variation. For continuous reactor sources, experiments involve the choice of a few wavelengths which optimize the sensitivity while giving manageable absorption corrections. When the time of flight diffraction method is employed at a pulsed neutron source with a diffractometer which gives full coverage of scattering angle, each Q-value is examined over a range of wavelengths and hence scattering lengths for the resonant nuclei. Sophisticated methods for absorption correction and data interpretation are essential if the full data set is to be used. The elements which can be studied by this technique are discussed and the calculation of the variation of the complex scattering length with neutron energy (wavelength) is described. One successful experiment (vitreous samarium aluminium germanate) and one unsuccessful (cadmium in a soda lime silicate glass) are described and the possibilities for the future are discussed. (author part.) 8 figs., 15 refs

  3. Gas multidetector for neutron and X-ray diffraction studies

    International Nuclear Information System (INIS)

    Allemand, R.

    1975-01-01

    In the context of nuclear imagery research the LETI is studying neutron, X-ray and γ-ray localisation detectors, the fields of application being neutron diffraction, X-ray diffraction and nuclear medicine. This report deals only with gas localisation methods, describing the physical results obtained in neutron and X-ray diffraction [fr

  4. Powder Neutron Diffraction and Magnetic structures

    International Nuclear Information System (INIS)

    Vigneron, F.

    1986-01-01

    The determination of the magnetic structures of materials (ferromagnetic, antiferromagnetic, helimagnetic, .) can be achieved only by neutron diffraction. A general survey of the powder technique is given: 2-axis spectrometer and analysis of the magnetic data. For the REBe/sb13/ intermetallic compounds (RE = Rare Earth), commensurate and/or incommensurate magnetic structures are observed and discussed as a function of RE (Gd, Tb, Dy, Ho, Er)

  5. Neutron powder diffraction and high Tc superconductors

    International Nuclear Information System (INIS)

    Hewat, A.W.

    1988-01-01

    Neutron powder diffraction is a technique for determining the crystalline structure and texture of materials for which single crystals cannot be obtained. As such it has made important contributions to the characterisation and understanding of the new high temperature superconductors. As well, NPD has wide applications in materials science, ranging from the study of catalyst and zeolite structures, to the texture of railway lines and composite superconducting wires. (orig.)

  6. Quasi-crystal structures with neutron diffraction

    International Nuclear Information System (INIS)

    Janot, C.

    1992-01-01

    Long-range order in materials can be aperiodic. This paper reports on quasi-periodic lattices that are mathematically derived from cross sections of objects that are periodically arranged in a higher dimensional space. Experimental investigations of these structures require the specification of more parameters than for classical crystallography. Neutron diffraction, with the special technique of contrast variation, allows a reasonable approach to this problem

  7. A simple furnace for neutron diffraction studies

    International Nuclear Information System (INIS)

    Bailey, F.P.; Bennett, C.E.G.

    1979-01-01

    A simple yet effective high temperature furnace for heating crystals or powder specimens for neutron diffraction studies on a theta/2theta diffractometer is described. The furnace can maintain samples at temperatures up to 1573 K, in air, with a stability of +- 4 K for periods of many hours. Specimen temperature is uniform within 12 K, or much less with the use of a silica sleeve. (Auth.)

  8. TOF neutron diffraction study of archaeological ceramics

    International Nuclear Information System (INIS)

    Kockelmann, W.; Kirfel, A.

    1999-01-01

    Complete text of publication follows. The time-of flight (TOF) neutron diffractometer ROTAX [1] at ISIS has been used for identification and quantitative phase analysis of archaeological pottery. Neutron diffraction yields mineral phase fractions which, in parallel with information obtained from other archaeometric examination techniques, can provide a fingerprint that can be used to identify provenance and reconstruct methods of manufacturing of an archaeological ceramic product. Phase fractions obtained from a 13th century Rhenish stoneware jar compare well with those obtained from a powder sample prepared from the same fragment. This indicates that reliable results can be obtained by illuminating a large piece or even an intact ceramic object making TOF neutron diffraction a truly non-destructive examination technique. In comparison to X-ray diffraction, information from the bulk sample rather than from surface regions is obtained. ROTAX allows for a simple experimental set-up, free of sample movements. Programmes of archaeological study on ROTAX involve Russian samples (Upper-Volga culture, 5000-2000 BC), Greek pottery, (Agora/Athens, 500-300 BC), and medieval German earthenware and stoneware ceramics (Siegburg waster heap, 13-15th century). (author)

  9. In situ x-ray and neutron powder diffraction study of LaNi5-xSnx-H systems

    Science.gov (United States)

    Bowman, Robert C., Jr.; Nakamara, Yumiko; Akiba, Etsuo

    2004-01-01

    This paper will present results of in situ XRD measurements of LaNi4.75Sn0.25 .during the initial absorption-desorption cycle, These measurements were performed under a similar condition to that for LaNi4.75Al0.25 previously reported [1]. The data were analyzed by the Rietveld method. Lattice parameter change and strain formation accompanying hydride phase formation and decomposition will be discussed. In addition, results of in situ neutron diffraction of LaNi4.78Sn0.22, focusing on hydrogen occupation in the hydride phase, will be presented.

  10. Neutron powder diffraction study on fully hydrogenated amino acid molecules

    International Nuclear Information System (INIS)

    Jiao Xuesheng; Sun Kai; Han Wenze; Liu Yuntao; Chen Dongfeng

    2010-01-01

    The traditional methods for studying amino acid molecular structure are X-ray diffraction and neutron diffraction after deuteration. In this paper, X-ray diffraction, neutron powder diffraction and Raman scattering were used to study the molecular structure of alanine and leucine. Combination of infrared spectroscopy, compared with fully hydrogenated, partial deuterated and fully deuterated alanine molecules, it is shown that the traditional methods are not enough in the study of molecular structure. Meanwhile, the neutron powder diffraction method was used to measure the leucine molecule directly. It shows that neutron powder diffraction method can give the fine structure of leucine molecule. (authors)

  11. Neutron diffraction experiments on ordered silver nuclei at Picokelvin temperatures

    International Nuclear Information System (INIS)

    Annila, A.J.; Hakonen, P.J.; Lounasmaa, O.V.; Nummila, K.K.; Oja, A.S.; Tuoriniemi, J.T.; Clausen, K.N.; Lindgaard, P.-A.; Siemensmeyer, K.; Steiner, M.; Weinfurter, H.; Viertioe, H.E.

    1990-08-01

    Nuclear spins in silver constitute an ideal antiferromagnetic spin - 1/2 model system in an fcc lattice. The nuclei are well localized and the interactions coupling the spins can be calculated from first principles. Strong quantum effects are expected owing to spin - 1/2. The magnetic phase diagram of the system has been investigated by several theoretical methods. In the present study the feasibility of neutron diffraction experiments on nuclear magnetic order in silver is discussed. The requirements for cryogenics and for neutron equipment are based on experience with current NMR measurements on sivler and with neutron diffraction work on copper. It is concluded that an experiment using an isotopically enriched specimen of either 107 Ag or 109 Ag is feasible but difficult. (author) 1 tab., 16 ills., 38 refs

  12. Neutron-diffraction measurements of stress

    International Nuclear Information System (INIS)

    Holden, T.M.

    1995-01-01

    Experiments on bent steam-generator tubing have shown that different diffraction peaks, (1 1 1) or (0 0 2), give different results for the sign and magnitude of the stress and strain. From an engineering standpoint, the macroscopic stress field cannot be both positive and negative in the same volume, so this difference must be due to intergranular effects superposed on the macroscopic stress field. Uniaxial tensile test experiments with applied stresses beyond the 0.2% offset yield stress, help to understand this anomaly, by demonstrating the different strain response to applied stress along different crystallographic axes.When Zr-alloys are cooled from elevated temperatures, thermal stresses always develop, so that it is difficult to obtain a stress-free lattice spacing from which residual strains may be derived. From measurements of the temperature dependence of lattice spacing, the temperature at which the thermal stresses vanish may be found. From the lattice spacing at this temperature the stress-free lattice spacings at room temperature can be obtained readily.To interpret the measured strains in terms of macroscopic stress fields it is necessary to know the diffraction elastic constants. Neutron diffraction measurements of the diffraction elastic constants in a ferritic steel for the [1 1 0], [0 0 2] and [2 2 2] crystallographic axes, in directions parallel and perpendicular to the applied stress are compared with theoretical diffraction elastic constants. (orig.)

  13. Workshop on industrial application of neutron diffraction. Stress measurement by neutron diffraction

    CERN Document Server

    Minakawa, N; Morii, Y; Oyama, Y

    2002-01-01

    This workshop was planned to make use of the neutron from the reactor and the pulse neutron source JSNS for the industrial world. Especially, this workshop focused on the stress measurement by the neutron diffraction and it was held on the Tokai JAERI from October 15 to 16, 2001. The participant total was 93 and 40 participated from the industrial world. The introduction of the residual stress development of measurement technique by the neutron diffraction method and a research of the measurement of the residual stress such as the nuclear reactor material, the ordinary structure material, the composite material, the quenching steel, the high strength material were presented and discussed in this workshop. Moreover, it was introduced for the industrial world that an internal stress measurement is important for development of new product or an improvement of a manufacturing process. The question from the industrial world about which can be measured the product form, the size, the measurement precision, the reso...

  14. Condensed medium neutron-diffraction study in JINR

    International Nuclear Information System (INIS)

    Balagurov, A.M.; Natkanets, I.; Ostanevich, Yu.M.

    1986-01-01

    A brief review of development of neutron diffraction investigations into condensed media in JINR is given. Structural neutron diffraction and dynamics of condensed media are considered. Commissioning of the IBR-2 reactor allowed one to investigate segnetoelectric and segnetoelastic crystals, conduct first experiments on neutron diffraction, using a monocrystal of myoglobin muscle protein. Texture neutron diffraction method is being developed. Simultaneously with the start-up activities, development of methods for experiments on the neutron inelastic scattering has begun. Two different experimental problems were solved: elementary excitation spectrum investigation and search for Bose-condensate. The growth of the JINR science and technology potential is accompanied by a rapid expansion of international cooperation

  15. Single-crystal neutron diffraction analysis in chemistry

    International Nuclear Information System (INIS)

    Hosoya, Takaaki; Ohhara, Takashi

    2010-01-01

    Single-crystal neutron diffraction technique is a powerful method to analyze the reaction mechanism whose hydrogen atom or proton has a key role in the reaction. Especially hydrogen atom or proton transfer(HT/PT) is one of the most elemental phenomena and often observed in many organic, inorganic, enzymatic and catalytic reactions. We describe several applications in chemistry. At first, hydrogen atom in metal hydride complexes, which is quite difficult to do using X-ray diffraction because of the great cloud of electrons of central metal atom. Secondary, hydrogen atom in hydrogen-bonding network, e.g., low-barrier hydrogen bond(LBHB) system. Neutron diffraction can refine the thermal motion of hydrogen atom. Finally, our results, photo-induced HT/PTs using 'deuterium atom labeling' technique and 'crystalline-state reaction' technique, which are currently developing applications. Despite the success illustrated by the many studies presented here or many other studies, we have many problems in using single-crystal neutron diffraction technique. For example, extremely limited flux and the requirement for mm-size sample crystals. Now, these limitations are being solved by the operation of powerful instruments at a new generation of pulsed neutron sources, including iBIX diffractometer running at Japan Proton Accelerator Research Complex(J-PARC) in Japan. (author)

  16. Neutron powder diffraction study of methane hydrate

    International Nuclear Information System (INIS)

    Ishii, Yoshinobu

    2005-01-01

    Neutron powder diffraction study of methane hydrate has been conducted in the temperature range of 7 K to 185 K. The diffraction data were analyzed by the Rietveld refinement and the Maximum Entropy Method (MEM). From MEM analysis, we obtained the scattering-length density distributions in a 3-dimensional image. The scattering-length density corresponding to C atom of the methane molecule was appeared and no density of H atoms was found in the small cage over the measured temperature range. On the other hand, in the large cage the scattering-length densities related to both H atom and C atom were observed at low temperature. The scattering-length density of H atom disappeared with increasing temperature, and then the scattering-length density of methane was almost gone at high temperature. These results show the motion of methane molecules differ in the small cage as compared to the large cage

  17. Oxides neutron and synchrotron X-ray diffraction studies

    CERN Document Server

    Sosnowska, I M

    1999-01-01

    We review some results from several areas of oxide science in which neutron scattering and X-ray synchrotron scattering exercise a complementary role to high-resolution transmission electron microscopy. The very high-resolution time-of-flight neutron diffraction technique and its role in studies of the magnetic structure of oxides is especially reviewed. The selected topics of structural studies for the chosen oxides are: crystal and magnetic structure of the so-called cellular random systems, magnetic structure and phase transitions in ferrites and the behaviour of water in non-stoichiometric protonic conductors and in the opal silica-water system. (40 refs).

  18. Neutron diffraction studies of rare-earth doped borate glasses

    International Nuclear Information System (INIS)

    Vaz, W.A.; Desa, J.A.E.; Krishna, P.S.R.; Shinde, A.B.

    2013-01-01

    Rare-earth ions included in glassy host networks have been studied as prototype systems for nuclear waste management. They are known to exhibit well defined absorptions in the visible region. Optical studies of glasses doped with two different rare-earth ions have been shown to display absorption spectra that are linear combinations of the component rare-earths appropriately weighted by their relative proportions in the glass. Investigations of local structure by diffraction methods may lead to an understanding of the origin of such rare-earth ion interactions. A set of borate glasses have been prepared in which Nd and Pr ions were included in the relative proportions of 1:3 and 3:1 for the two ions. Alumina was added (5 mole%) for ease of preparation and the borate component was 75%. The glasses were quenched in air at room temperature. The host glass was prepared from 11 B boric acid for the neutron diffraction measurements. The data presented here were from X-ray diffraction (CuK α Rigaku D-MAX/B rotating anode) and neutron diffraction using the High Q diffractometer at Dhruva Reactor, B.A.R.C., For both types of measurement, the glasses were crushed to fine powders. The neutron data were collected with the powders in 6 mm diameter, 5 cm high vanadium cans. The structure factors of both glasses and that for the undoped borate glass from the neutron diffraction data are shown. The total correlation functions T(r) are displayed. The presence of the R-O correlations may be observed at about 3.2 Å. Separations of these correlations from both X-ray and neutron data will be presented. (author)

  19. Evolution of the magnetic order in the Ho(Mn, Al) sub 2 system; neutron diffraction study

    CERN Document Server

    Golosovsky, I V; Markosyan, A S; Roisnel, T

    2002-01-01

    The neutron diffraction study of Ho(Mn sub 1 sub - sub x Al sub x) sub 2 shows the coexistence of two cubic Laves phases with different unit-cell parameters and substantially different magnetic behaviours. The first phase combines ordered ferrimagnetic and disordered antiferromagnetic components of the magnetic moments. With increasing Al content, starting from the long-range ferrimagnetic order with the induced Mn moment in HoMn sub 2 , the progressive formation of spontaneous Mn moments yields short-range order, which in turn transforms to ferromagnetic order in HoAl sub 2. The second phase with incommensurate magnetic structure is driven by the spontaneous Mn moments and exists only over limited ranges of Al content and unit-cell parameter. It has a finite correlation length and appears from a second-order transition without a magneto-volume effect.

  20. Neutron diffraction studies of chemical structure and interaction

    International Nuclear Information System (INIS)

    Lehmann, M.S.

    1985-01-01

    The analysis of chemical structure, using neutron crystallography, is reviewed. First the various aspects of neutron diffraction are discussed and special advantages are outlined. Then various themes within the study of three-dimensional crystalline material are treated. The most traditional of these, the location of light atoms in structures, is shown to remain important, and likewise high-precision work still gives much new information. Within the last decade powder analysis has become a tool in chemical analysis. This is partly due to developments in monochromator technology, computer applications and large area detectors. For very similar reasons studies of materials in real time and under extreme conditions are becoming frequent. We therefore observe both a continuing use of traditional neutron crystallographic techniques, and a growth of new methods and areas which depend on instrumental developments. With the advent of new sources and larger detector systems, further advances can thus be expected in the application of neutrons in structural chemistry. (author)

  1. Engineering Applications of Time-of-Flight Neutron Diffraction

    Science.gov (United States)

    Clausen, Bjørn; Brown, Donald W.; Noyan, I. C.

    2012-01-01

    Time-of-flight neutron diffraction is widely used in characterizing the microstructure and mechanical response of heterogeneous systems. Microstructural characterization techniques include spatial or temporal mapping of the phases and determination of grain size, dislocation structure, and grain orientations (texture) within these phases. Mechanical response analysis utilizes the crystallographic selectivity of the diffraction process to measure the partitioning of strain within the system. The microstructural and mechanical response information is then used to develop more realistic constitutive models. In this article we review some examples of such measurements, based on our experiences at the Lujan Center of Los Alamos National Laboratory.

  2. High resolution Neutron and Synchrotron Powder Diffraction

    International Nuclear Information System (INIS)

    Hewat, A.W.

    1986-01-01

    The use of high-resolution powder diffraction has grown rapidly in the past years, with the development of Rietveld (1967) methods of data analysis and new high-resolution diffractometers and multidetectors. The number of publications in this area has increased from a handful per year until 1973 to 150 per year in 1984, with a ten-year total of over 1000. These papers cover a wide area of solid state-chemistry, physics and materials science, and have been grouped under 20 subject headings, ranging from catalysts to zeolites, and from battery electrode materials to pre-stressed superconducting wires. In 1985 two new high-resolution diffractometers are being commissioned, one at the SNS laboratory near Oxford, and one at the ILL in Grenoble. In different ways these machines represent perhaps the ultimate that can be achieved with neutrons and will permit refinement of complex structures with about 250 parameters and unit cell volumes of about 2500 Angstrom/sp3/. The new European Synchotron Facility will complement the Grenoble neutron diffractometers, and extend the role of high-resolution powder diffraction to the direct solution of crystal structures, pioneered in Sweden

  3. Growing Larger Crystals for Neutron Diffraction

    Science.gov (United States)

    Pusey, Marc

    2003-01-01

    Obtaining crystals of suitable size and high quality has been a major bottleneck in macromolecular crystallography. With the advent of advanced X-ray sources and methods the question of size has rapidly dwindled, almost to the point where if one can see the crystal then it was big enough. Quality is another issue, and major national and commercial efforts were established to take advantage of the microgravity environment in an effort to obtain higher quality crystals. Studies of the macromolecule crystallization process were carried out in many labs in an effort to understand what affected the resultant crystal quality on Earth, and how microgravity improved the process. While technological improvements are resulting in a diminishing of the minimum crystal size required, neutron diffraction structural studies still require considerably larger crystals, by several orders of magnitude, than X-ray studies. From a crystal growth physics perspective there is no reason why these 'large' crystals cannot be obtained: the question is generally more one of supply than limitations mechanism. This talk will discuss our laboratory s current model for macromolecule crystal growth, with highlights pertaining to the growth of crystals suitable for neutron diffraction studies.

  4. Microstructure of Horseshoe Nails Using Neutron Diffraction

    Science.gov (United States)

    Goossens, D. J.; Studer, A. J.; Stachurski, Z. H.

    2010-04-01

    Neutron diffraction allows nondestructive testing of the bulk microstructure of mechanical components. The microstructures of horseshoe nails made through three different processes have been explored as a function of position along the nail. Despite all nails being made of similar plain low-carbon steel and being process annealed after manufacture, the microstructures are far from the same. Nails made from strip, using a cold forging stamping process, show narrower diffraction peaks indicating a narrower distribution of lattice parameters and also show diffraction peak intensity ratios closer to those expected for unstrained steel. Thus, the distribution of the orientation of grains in these nails is closer to that of undistorted steel compared to nails made through the other two processes considered—one a drawing from wire and the other a combination of rolling and cold forging. The blades of the drawn nails showed little preferred orientation but the converse was true in the heads. Differing patterns of preferred orientation suggest that the various manufacturing approaches result in substantially different mechanical advantages for the three types of nails, a result in accord with mechanical testing.

  5. Metallic microstructure analysis using TOF type pulse neutron diffraction

    International Nuclear Information System (INIS)

    Sato, Shigeo; Nakagawa, Maiko; Onuki, Yusuke; Hoshikawa, Akinori; Yamanaka, Kenta; Tomida, Toshiro

    2017-01-01

    In the iMATERIA beamline of J-PARC MLF, detectors are arranged three-dimensionally against a sample. The use of TOF type pulse neutron diffraction using this optical system has made it possible to measure the texture, phase fraction, and dislocation, simultaneously and quickly. This paper outlined the characteristics and measurement system of TOF type diffraction in iMATERIA, and introduced the quantitative accuracy/reliability of the obtained microstructure information, as well as the possibility of future application development. The iMATERIA has about 1,500 units of 3 He-one-dimensional position sensitive detectors, and three detector banks are arranged in the diffraction angle region from low angle to high angle so as to surround the sample. Due to the features of this configuration and resolution, line profile analysis for dislocation and pole figure measurement for texture are possible. In texture analysis using TOF type neutron diffraction, the pole figure can be measured without sample rotation, which enables the tracking of dynamic texture change. In the phase fraction analysis based on texture analysis, the phase fraction could be obtained for the sample with about 1% of austenite volume fraction, with the same accuracy as that with 100%. As an application example of microstructure analysis associated with martensitic transformation, the martensite phase fraction of the cold rolled alloy was compared with the measurement of the conventional electron backscatter diffraction (EBSD) method, and the difference was discussed. (A.O.)

  6. Optimizing crystal volume for neutron diffraction: D-xylose isomerase.

    Science.gov (United States)

    Snell, Edward H; van der Woerd, Mark J; Damon, Michael; Judge, Russell A; Myles, Dean A A; Meilleur, Flora

    2006-09-01

    Neutron diffraction is uniquely sensitive to hydrogen positions and protonation state. In that context structural information from neutron data is complementary to that provided through X-ray diffraction. However, there are practical obstacles to overcome in fully exploiting the potential of neutron diffraction, i.e. low flux and weak scattering. Several approaches are available to overcome these obstacles and we have investigated the simplest: increasing the diffracting volume of the crystals. Volume is a quantifiable metric that is well suited for experimental design and optimization techniques. By using response surface methods we have optimized the xylose isomerase crystal volume, enabling neutron diffraction while we determined the crystallization parameters with a minimum of experiments. Our results suggest a systematic means of enabling neutron diffraction studies for a larger number of samples that require information on hydrogen position and/or protonation state.

  7. Fundamentals and applications of neutron diffraction. Applications 5. Crystal structure analysis of high-Tc oxide superconductors by neutron diffraction

    International Nuclear Information System (INIS)

    Mochiku, Takashi

    2010-01-01

    Crystal structure analysis with neutron diffraction is necessary for the study of high-T c oxide superconductors, which oxygen atoms play an important role in. The crystal structure of a lot of superconductors has been analyzed by neutron powder diffraction. On the basis of the neutron powder diffraction study, the guiding principle of material design in high-T c oxide superconductors has been constructed, and contributes the discovery of new materials. The crystallographic data obtained by the neutron powder diffraction study is also the fundamentals to the study for the exotic physical properties in high-T c oxide superconductors. (author)

  8. Pulsed Neutron Powder Diffraction for Materials Science

    Science.gov (United States)

    Kamiyama, T.

    2008-03-01

    The accelerator-based neutron diffraction began in the end of 60's at Tohoku University which was succeeded by the four spallation neutron facilities with proton accelerators at the High Energy Accelerator Research Organization (Japan), Argonne National Laboratory and Los Alamos Laboratory (USA), and Rutherford Appleton Laboratory (UK). Since then, the next generation source has been pursued for 20 years, and 1MW-class spallation neutron sources will be appeared in about three years at the three parts of the world: Japan, UK and USA. The joint proton accelerator project (J-PARC), a collaborative project between KEK and JAEA, is one of them. The aim of the talk is to describe about J-PARC and the neutron diffractometers being installed at the materials and life science facility of J-PARC. The materials and life science facility of J-PARC has 23 neutron beam ports and will start delivering the first neutron beam of 25 Hz from 2008 May. Until now, more than 20 proposals have been reviewed by the review committee, and accepted proposal groups have started to get fund. Those proposals include five polycrystalline diffractometers: a super high resolution powder diffractometer (SHRPD), a 0.2%-resolution powder diffractometer of Ibaraki prefecture (IPD), an engineering diffractometers (Takumi), a high intensity S(Q) diffractometer (VSD), and a high-pressure dedicated diffractometer. SHRPD, Takumi and IPD are being designed and constructed by the joint team of KEK, JAEA and Ibaraki University, whose member are originally from the KEK powder group. These three instruments are expected to start in 2008. VSD is a super high intensity diffractometer with the highest resolution of Δd/d = 0.3%. VSD can measure rapid time-dependent phenomena of crystalline materials as well as glass, liquid and amorphous materials. The pair distribution function will be routinely obtained by the Fourier transiformation of S(Q) data. Q range of VSD will be as wide as 0.01 Å-1Software group is

  9. Workshop on industrial application of neutron diffraction. Stress measurement by neutron diffraction

    International Nuclear Information System (INIS)

    Minakawa, Nobuaki; Moriai, Atsushi; Morii, Yukio; Oyama, Yukio

    2002-03-01

    This workshop was planned to make use of the neutron from the reactor and the pulse neutron source JSNS for the industrial world. Especially, this workshop focused on the stress measurement by the neutron diffraction and it was held on the Tokai JAERI from October 15 to 16, 2001. The participant total was 93 and 40 participated from the industrial world. The introduction of the residual stress development of measurement technique by the neutron diffraction method and a research of the measurement of the residual stress such as the nuclear reactor material, the ordinary structure material, the composite material, the quenching steel, the high strength material were presented and discussed in this workshop. Moreover, it was introduced for the industrial world that an internal stress measurement is important for development of new product or an improvement of a manufacturing process. The question from the industrial world about which can be measured the product form, the size, the measurement precision, the resolution, and the installation plan of internal stress measurement equipment using the pulse neutron source under construction. From an expert, there was a question concerning on the internal stress distribution measurement about stress corrosion cracking etc. (author)

  10. Neutron diffraction studies of natural glasses

    International Nuclear Information System (INIS)

    Wright, A.C.; Erwin Desa, J.A.; Weeks, R.A.; Sinclair, R.N.; Bailey, D.K.

    1983-08-01

    A neutron diffraction investigation has been carried out of the structures of several naturally occurring glasses, viz. Libyan Desert glass, a Fulgurite, Wabar glass, Lechatelierite from Canon Diablo, a Tektite, Obsidian (3 samples), and Macusani glass. Libyan Desert sand has also been examined, together with crystalline α-quartz and α-cristobalite. A comparison of data for the natural glasses and synthetic vitreous silica (Spectrosil B) in both reciprocal and real space allows a categorisation into Silicas, which closely resemble synthetic vitreous silica, and Silicates, for which the resemblance to silica is consistently less striking. The data support the view that Libyan Desert glass and sand have a common origin, while the Tektite has a structure similar to that of volcanic glasses

  11. Material evaluation by means of neutron diffraction

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2017-01-01

    Various experiments using pulse neutrons are being carried out at the Material and Life Science Experimental Facility of Japan Proton Accelerator Experimental Facility (J-PARC MLF). This paper took up a material evaluation technology utilizing diffraction phenomena making use of high permeability, and introduced the measurements of residual stress, crystal structure analysis with discrimination of elements, texture identification, and phase fraction. When neutron diffraction is used for residual stress measurement, it is possible to measure an aeon piece of about 30 mm in thickness and the inside of an car engine block made of aluminum alloy. As a measurement example, in the case of STPT410 carbon steel butt welded pipe joint, from the residual stress distribution in the three axial directions, high residual stress is seen in the circumferential direction and the maximum tensile stress is 200 MPa or more. These distributions almost agree with analysis values using other methods. From the residual stress on the cylinder wall surface of 1,500 cc aluminum alloy engine block, it was thought that the cylinder wall could be thinned by 1 mm unit. The time required for the texture measurement of metals is about one minute, which is 1/100 or less of the X-ray method. As an analytical example of light elements such as Li that cannot be analyzed with X-rays, in the crystal structure analysis of Li electrodes for Li ion batteries, this method is used for the analysis of fine crystal structure during charging and discharging processes. (A.O.)

  12. Magnetization and neutron diffraction studies on FeCrP

    Indian Academy of Sciences (India)

    physics pp. 199–205. Magnetization and neutron diffraction studies on FeCrP. SUDHISH KUMARa,†, ANJALI KRISHNAMURTHYb, BIPIN K SRIVASTAVAb, .... Neutron diffraction pattern at 300 K. Observed (calculated) pro- files are shown by dotted (solid) curves. The short vertical marks represent. Bragg reflections.

  13. Single crystal neutron diffraction study of triglycine sulphate revisited

    Indian Academy of Sciences (India)

    atom positions in TGS crystals, neutron diffraction study on TGS was once again undertaken, since neutron diffraction is known to be the only method, which gives exact hydrogen atom position. 2. Experiment. A clear rectangular single crystal of TGS of dimension 3×3.5×3 mm was loaded on a goniometer, which was then ...

  14. Deformation Behavior of An Austenitic Steel by Neutron Diffraction

    Science.gov (United States)

    Harjo, Stefanus; Abe, Jun; Aizawa, Kazuya; Gong, Wu; Iwahashi, Takaaki

    An austenitic stainless steel type 304, which is one of the most popular materials in use, was tensile deformed and in situ neutron diffraction measurement was performed. The neutron diffraction measurement was conducted using an engineering materials diffractometer installed at MLF/J-PARC. Because of the combination of the high neutron intensity, the high counting rate and an event data recording method, in situ neutron diffraction during tensile loading at plastic deformation could be performed without any interruption for load or displacement. Intergranular strains and bulky stress observed during deformation were discussed on the crystal orientation dependence.

  15. Nondestructive determination of materials parameters by neutron diffraction

    International Nuclear Information System (INIS)

    Brokmeier, H.G.; Bunge, H.J.

    1989-01-01

    Using the high transmission of neutron radiation, neutron diffraction is described to be an efficient tool for the analysis of various materials parameters of the bulk of a material in a nondestructive way. Sample sizes up to 40 mm in diameter have been used to determine the phase composition, texture and internal stresses of polycrystalline, polyphased materials. Additionally to well-known X-ray techniques which analyse the surface of a sample, neutron diffraction measurements are carried out to investigate the average behaviour of a bulk sample or the local behaviour within a compact sample. Further advantages of neutron diffraction are that small volume fractions (e.g. 0.05 Vol.% Cu in Al) can be determined. Moreover, in the case of X-ray diffraction the examination of coarse-grained materials and of complex multiphase materials is limited, and neutron diffraction has to be used. (orig./RHM)

  16. Neutron Diffraction Measurements using the Cairo Fourier Diffractometer facility

    International Nuclear Information System (INIS)

    Maayof, R.M.A.; Elkady, A.S.

    1999-01-01

    The paper presents neutron diffraction investigations of different polycrystalline materials, performed at room temperature, using the Cairo Fourier Diffractometer Facility (CFDF),recently installed at one of the ET-RR-1 reactor horizontal channels. The neutron diffraction patterns were measured using the CFDF while its Fourier chopper was rotating with modulation frequency 136 KHz ;leading to-7us for the FWHM of the time resolution function. The diffraction patterns were analysed by a special program (MRIA), adapted especially to the CFDF conditions. The reliability of the C DF results was confirmed from comparison of the measured diffraction patterns with similar ones obtained from neutron and x-ray measurements

  17. Neutron diffraction under high pressure and high temperature

    International Nuclear Information System (INIS)

    Komatsu, Kazuki

    2010-01-01

    Neutron diffraction study under high pressure and high temperature is reviewed from the technical point of view. Particularly, cell assembly for the high-PT neutron diffraction using a Paris-Edinburgh cell with the temperature calibration by neutron resonance spectroscopy is introduced. Notes on the errors relevant to high pressure and high temperature experiments in both monochromatic angle dispersive and time-of-flight methods are also discussed. (author)

  18. Finishing a series of lectures on neutron diffraction

    International Nuclear Information System (INIS)

    Morii, Yukio; Fujii, Yasuhiko

    2011-01-01

    A serial lecture on neutron diffraction, small angle scattering and reflectivity in both the stationary and pulse neutrons has been made from the fundamental to the application field with the easy expression. In the fundamental section the principle, technique and knowledge on neutron diffraction are explained easily. In the application section the research contents of social interest and the examples of industrial use are taken up. (M.H.)

  19. Diffraction measurements with a boron-based GEM neutron detector

    Science.gov (United States)

    Croci, Gabriele; Albani, Giorgia; Cazzaniga, Carlo; Perelli Cippo, Enrico; Schooneveld, Erik; Claps, Gerardo; Cremona, Anna; Grosso, Giovanni; Muraro, Andrea; Murtas, Fabrizio; Rebai, Marica; Scherillo, Antonella; Tardocchi, Marco; Gorini, Giuseppe

    2014-07-01

    The research of reliable substitutes of 3He detectors is an important task for the affordability of new neutron scattering instrumentation for future spallation sources like the European Spallation Source. GEM (Gas Electron Multiplier)-based detectors represent a valid alternative since they can combine high-rate capability, coverage of up to 1\\ \\text{m}^{2} area and good intrinsic spatial resolution (for this detector class it can be better than 0.5 mm). The first neutron diffraction measurements performed using a borated GEM detector are reported. The detector has an active area of 10 \\times 5\\ \\text{cm}^{2} and is equipped with a borated cathode. The GEM detector was read out using the standard ISIS Data Acquisition System. The comparison with measurements performed with standard 3He detectors shows that the broadening of the peaks measured on the diffractogram obtained with the GEM is 20-30% wider than the one obtained by 3He tubes but the active area of the GEM is twice that of 3He tubes. The GEM resolution is improved if half of its active area is considered. The signal-to-background ratio of the GEM is about 1.5 to 2 times lower than that of 3He. This measurement proves that GEM detectors can be used for neutron diffraction measurements and paves the way for their use at future neutron spallation sources.

  20. Structural and magnetic properties probed using neutron diffraction technique in Ni50-xCoxMn38Sb12 (x=0 and 5) Heusler system

    Science.gov (United States)

    Sahoo, Roshnee; Suresh, K. G.; Das, A.

    2014-12-01

    Magnetization and neutron diffraction studies have been carried out in Ni50-xCoxMn38Sb12 (x=0 and 5) to investigate the effect of Co on the structural and magnetic properties. A comparison of the neutron diffraction data of Ni45Co5Mn38Sb12 and Ni50Mn38Sb12 alloys shows that Co substitution leads to an increase in the Mn moments. Considerably large magnetization difference associate with martensitic transition has also been observed on Co substitution. The analysis of the neutron diffraction data has revealed that the martensitic transition is accompanied by about 70% decrease in the moment and about 0.3% decrease in the cell volume. Enhanced magneto-structural coupling resulting from the Co doping has been evidenced by the magnetization as well as the neutron data. The variations in the individual site moments on Co substitution and their temperature dependencies account for the observed bulk magnetization data.

  1. Stress measurement technique using neutron diffraction and its applications

    International Nuclear Information System (INIS)

    Suzuki, Hiroshi

    2010-01-01

    Neutron diffraction is the only method by which residual stresses inside materials at centimeter-order depth can be measured nondestructively. Residual lattice strains in (hkl) can be evaluated from the shift of the diffraction peak from its original position under the stress-free condition. Residual stresses can be calculated by applying Hooke's law to lattice strains measured in three orthogonal directions. In addition, the neutron diffraction method can evaluate macroscopic deformation of engineering materials by measuring microstructural factors such as microstrains. Therefore, the neutron diffraction technique is very helpful in the design and development of engineering components, as well as in studies on materials engineering. This paper shows principle of neutron stress measurement and engineering neutron diffractometers as well as some applications. (author)

  2. Neutron diffraction experience at RESA for engineering-aid application

    International Nuclear Information System (INIS)

    Tsuchiya, Yoshinori; Kato, Takashi; Nakajima, Hideo; Tsuji, Hiroshi; Kikuchi, Kenji; Minakawa, Nobuaki; Morii, Yukio

    2001-01-01

    In RESA facility, neutron diffractometer for residual stress analysis of JAERI, a neutron diffraction method of residual stress measurement has been developed. In engineering, an estimation of an applied strain by a machining process is important for a design and manufacturing goods. The neutron diffraction is expected to apply for such a practical application. In this study, the internal residual stress of a conduit material used for a huge superconducting coil with a complex fabrication process was measured by the neutron diffraction in order to demonstrate the effectiveness of neutron diffraction measurement as an engineering-aid tool. Strain and stress applied by machining were estimated from the measurements of the conduit before and after machining. The results of the measurement were compared with the finite element method calculation. (author)

  3. Nondestructive determination of residual stresses by neutron diffraction

    International Nuclear Information System (INIS)

    Tello, H.; Barrera, E.V.

    1993-01-01

    Nondestructive determination of residual stresses and strains in engineering materials has been limited to analytical models and near-surface measurement techniques such as x-ray diffraction and ultrasonic testing. The use of neutron diffraction for residual stress determination is similar in methodology to x-ray diffraction but provides superior analysis capability because of the lower absorption of neutrons in most materials. Neutron diffraction measurements can be made from sampling depths of several millimeters in most materials as compared to micrometer sampling depth of x-rays. This paper will discuss the principles of neutron diffraction as well as the advantages and limitations of the technique. Specific examples of residual stress measurements using conventional and time-of flight techniques will be provided

  4. Diffraction of neutrons in crystals macroscopic double slits

    International Nuclear Information System (INIS)

    Lacroix, A.

    2000-06-01

    Diffraction experiments with neutrons at slits in free space have been measured with very high accuracy and can be found in many text books. The experiments in this thesis demonstrate that diffraction still takes place when the ratio between the dimensions of the slits and the wavelength of the particle is very large. In our experiment neutrons are diffracted at macroscopic objects and these diffraction effects will be amplified in a silicon crystal. The following effect is used : Similar to electrons in solid state materials, the interaction of the neutron with a periodic crystal potential can be described by an effective mass. In contrast to the case of the electrons, however, the crystal potential is very small in comparison to the kinetic energy for neutrons. Thus the effective neutron mass can become almost six orders of magnitude smaller than the rest mass of the free neutron. Therefore the characteristic length, equivalent to the de Broglie wavelength in free space, inside the crystal is the Pendelloesung length which is in our case larger by a factor of 2x10 5 . Due to this fact a deflection by small forces can already be observed on a distance of some centimeters. Thus diffraction of neutrons with wavelengths of the order of a few angstroms at slits in the millimeter range can be shown. We remark that our intensity was of the order of 4 neutrons per minute which clearly indicates single-neutron interference. (author)

  5. Progress in bulk texture measurement using neutron diffraction

    International Nuclear Information System (INIS)

    Xu, Pingguang; Suzuki, Hiroshi; Akita, Koichi; Harjo, Stefanus; Gong, Wu; Tomota, Yo; Ito, Takayoshi; Morii, Yukio; Suzuki, Tetsuya; Lutterotti, Luca

    2015-01-01

    The current status of bulk texture measurements both using angle dispersive neutron diffraction and time-of-flight neutron diffraction at JAEA was briefly reviewed, then the effect of sample orientation coverage in the time-of-flight neutron diffraction on the reliability of reconstructed pole figure on the reliability of reconstructed pole figure was simply compared after the simultaneous Rietveld texture analysis. The similar texture results obtained at different orientation coverage levels suggests that it is possible to reduce the sample rotation times reasonably during the bulk texture measurement. (author)

  6. High-pressure gas chamber for neutron diffraction studies

    International Nuclear Information System (INIS)

    Stepanov, G. N.; Telepnev, A. S.; Simkin, V. G.

    2007-01-01

    The construction of a chamber designed for neutron diffraction studies of the structure of solids under high gas pressures up to 0.5 GPa is described. This chamber is a modification of the chamber published earlier

  7. Neutron diffraction determination of atomic mean-square displacements in cubic compounds of Ni-Al and Ni-Al-Cu systems

    International Nuclear Information System (INIS)

    Khidirov, I.; Mukhtarova, N.N.

    2002-01-01

    The atomic mean-square displacements (AMSD) are some of important characteristics of the solid and can be the main information for determination of a number of other characteristics of substances. In the work AMSD is determined for a number of cubic compounds of Ni-Al, Ni-Al-Cu systems immediately from intensities of neutron diffraction maxima. It is shown by the offered method that in all NiAl x and NiAlCu x compounds with the CsCl - type structure AMSD are near each other and they are practically constant. Therefore it is possible to assume that within the homogeneity region of these compounds the interatomic bond forces are changed insignificantly

  8. Measurements of residual stresses and textures by neutron diffraction

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2008-01-01

    Many measurement methods of residual stress are compared and characteristic properties of neutron diffraction method are described. The penetration depth of neutron, photon radiation and Cu-Kα ray to metals are compared and the values of neutron are larger than others. Two kinds of measurement methods of residual stress by neutron diffraction, the angular scattering and the time of flight method, are explained. The results of measurement of residual stresses of carbon steel and titanium butt weld joint, Wasploy alloy, aluminum alloy and Incoloy 800 tube in stream generator of nuclear power plant are reported. Neutron diffraction profile of SiCp/Al2024-T6 was measured by TOF method. The textures of Zr-2.5% Nb and SUS316 steel were observed. (S.Y.)

  9. Measurement of internal stress within bulk materials using neutron diffraction

    International Nuclear Information System (INIS)

    Allen, A.; Andreani, C.; Hutchings, M.T.; Windsor, C.G.

    1981-01-01

    Neutron diffraction measures stress through the small changes in atomic lattice parameters caused by strain. The method is similar to X-ray diffraction with the vital difference that a thermal neutron beam penetrates several centimetres in most materials allowing measurements within bulk samples. Ways of achieving the high resolution necessary for quantitative measurements are described. Results are presented for the strains in a mild steel bar subjected to known elastic stresses, and on the internal stresses in a deformed bar. (author)

  10. Residual stresses analysis by X-ray and neutrons diffraction

    International Nuclear Information System (INIS)

    Lodini, A.; Perrin, M.

    1996-04-01

    This conference is composed of 17 papers grouped in 13 chapters which main themes are: advantages of neutrons and synchrotron radiation for material characterization; residual stress evaluation from micro-deformation measurements in polycrystalline materials; X-ray and neutron diffractometry; residual stress evaluation by X-ray diffraction in extreme surfaces; residual stress diffraction evaluation in monocrystalline nickel base alloys, in polyphasic materials, composite materials, thin films, multilayers and joints; application to thermonuclear reactor components

  11. Residual Stress Measurement of Titanium Casting Alloy by Neutron Diffraction

    Science.gov (United States)

    Nishida, M.; Jing, T.; Muslih, M. R.; Hanabusa, T.

    2008-03-01

    Neutron stress measurement can detect strain and stress information in deep region because of large penetration ability of neutron beams. The present paper describes procedure and results in the residual stress measurement of titanium casting alloy by neutron diffraction. In this study, the three axial method using Hooke's equation was employed for neutron stress measurement. This method was applied to the cylindrical shape sample of titanium casting alloy (Ti-6Al-4V). Form the results of this study, this sample has large crystal grain in the inside whole position, it is assumed this large grain was grown up during casting manufacture process. Furthermore, the peak profile used to the stress measurement appears in very weak because of the HCP crystal system of titanium character and effect of large crystal grain. These conditions usually make difficult to measure the accuracy values of residual stresses. Therefore, it had to spend a long time to measure the satisfied data from titanium sample. Regarding to the results of stress measurement, the stress values in the cylindrical sample of three directions is almost same tendency, and residual stresses change from the compressive state in the outer part to the tensile state in the inner part gradually.

  12. Future directions in high-pressure neutron diffraction

    Science.gov (United States)

    Guthrie, M.

    2015-04-01

    The ability to manipulate structure and properties using pressure has been well known for many centuries. Diffraction provides the unique ability to observe these structural changes in fine detail on lengthscales spanning atomic to nanometre dimensions. Amongst the broad suite of diffraction tools available today, neutrons provide unique capabilities of fundamental importance. However, to date, the growth of neutron diffraction under extremes of pressure has been limited by the weakness of available sources. In recent years, substantial government investments have led to the construction of a new generation of neutron sources while existing facilities have been revitalized by upgrades. The timely convergence of these bright facilities with new pressure-cell technologies suggests that the field of high-pressure (HP) neutron science is on the cusp of substantial growth. Here, the history of HP neutron research is examined with the hope of gleaning an accurate prediction of where some of these revolutionary capabilities will lead in the near future. In particular, a dramatic expansion of current pressure-temperature range is likely, with corresponding increased scope for extreme-conditions science with neutron diffraction. This increase in coverage will be matched with improvements in data quality. Furthermore, we can also expect broad new capabilities beyond diffraction, including in neutron imaging, small angle scattering and inelastic spectroscopy.

  13. Future directions in high-pressure neutron diffraction.

    Science.gov (United States)

    Guthrie, M

    2015-04-22

    The ability to manipulate structure and properties using pressure has been well known for many centuries. Diffraction provides the unique ability to observe these structural changes in fine detail on lengthscales spanning atomic to nanometre dimensions. Amongst the broad suite of diffraction tools available today, neutrons provide unique capabilities of fundamental importance. However, to date, the growth of neutron diffraction under extremes of pressure has been limited by the weakness of available sources. In recent years, substantial government investments have led to the construction of a new generation of neutron sources while existing facilities have been revitalized by upgrades. The timely convergence of these bright facilities with new pressure-cell technologies suggests that the field of high-pressure (HP) neutron science is on the cusp of substantial growth. Here, the history of HP neutron research is examined with the hope of gleaning an accurate prediction of where some of these revolutionary capabilities will lead in the near future. In particular, a dramatic expansion of current pressure-temperature range is likely, with corresponding increased scope for extreme-conditions science with neutron diffraction. This increase in coverage will be matched with improvements in data quality. Furthermore, we can also expect broad new capabilities beyond diffraction, including in neutron imaging, small angle scattering and inelastic spectroscopy.

  14. Cold neutron diffraction contrast tomography of polycrystalline material.

    Science.gov (United States)

    Peetermans, S; King, A; Ludwig, W; Reischig, P; Lehmann, E H

    2014-11-21

    Traditional neutron imaging is based on the attenuation of a neutron beam through scattering and absorption upon traversing a sample of interest. It offers insight into the sample's material distribution at high spatial resolution in a non-destructive way. In this work, it is expanded to include the diffracted neutrons that were ignored so far and obtain a crystallographic distribution (grain mapping). Samples are rotated in a cold neutron beam of limited wavelength band. Projections of the crystallites formed by the neutrons they diffract are captured on a two dimensional imaging detector. Their positions on the detector reveal their orientation whereas the projections themselves are used to reconstruct the shape of the grains. Indebted to established synchrotron diffraction contrast tomography, this 'cold neutron diffraction contrast tomography' is performed on recrystallized aluminium for experimental comparison between both. Differences between set-up and method are discussed, followed by the application range in terms of sample properties (crystallite size and number, mosaicity and typical materials). Neutron diffraction contrast tomography allows to study large grains in bulky metallic structures.

  15. Future directions in high-pressure neutron diffraction

    International Nuclear Information System (INIS)

    Guthrie, M

    2015-01-01

    The ability to manipulate structure and properties using pressure has been well known for many centuries. Diffraction provides the unique ability to observe these structural changes in fine detail on lengthscales spanning atomic to nanometre dimensions. Amongst the broad suite of diffraction tools available today, neutrons provide unique capabilities of fundamental importance. However, to date, the growth of neutron diffraction under extremes of pressure has been limited by the weakness of available sources. In recent years, substantial government investments have led to the construction of a new generation of neutron sources while existing facilities have been revitalized by upgrades. The timely convergence of these bright facilities with new pressure-cell technologies suggests that the field of high-pressure (HP) neutron science is on the cusp of substantial growth. Here, the history of HP neutron research is examined with the hope of gleaning an accurate prediction of where some of these revolutionary capabilities will lead in the near future. In particular, a dramatic expansion of current pressure-temperature range is likely, with corresponding increased scope for extreme-conditions science with neutron diffraction. This increase in coverage will be matched with improvements in data quality. Furthermore, we can also expect broad new capabilities beyond diffraction, including in neutron imaging, small angle scattering and inelastic spectroscopy. (topical review)

  16. Neutron diffraction and the physical properties of the light actinides

    International Nuclear Information System (INIS)

    Lawson, A.C.; Cort, B.; Roberts, J.A.; Bennett, B.I.; Richardson, J.W. Jr.

    1998-01-01

    For the past few years the authors have been applying the techniques of neutron powder diffraction to questions arising from the peculiar properties of the light actinide metals. The peculiar properties include complicated crystal structures, leading to complex phase diagrams; anomalous elastic and thermal expansion behavior; and surprisingly low melting points, especially for plutonium. The authors have made neutron diffraction studies of α-thorium, α-neptunium, α-uranium, and α- and δ-plutonium. A great deal has been learned from a study of the temperature dependence of the thermal vibrations of the light actinides. These can be determined using neutron diffraction to measure the Debye-Waller factors in powder diffraction experiments. The same neutron diffraction experiments also give information on the linear coefficient of thermal expansion α. This quantity is also strongly temperature dependent. Other neutron diffraction work is in progress, including attempts to solve some of the unknown alloy structures of Pu, and texture analysis via pole-figure measurements. The texture measurements are of particular interest, given the elastic anisotropy. High-quality data on Pu require the use of the nonabsorbing 242 Pu isotope, and this is a disadvantage. However, the high penetration of neutrons into most materials means that many safety problems can be solved by encapsulation of the radioactive material in V or other metal

  17. Single crystal neutron diffraction study of triglycine sulphate revisited

    Indian Academy of Sciences (India)

    Abstract. In order to get the exact hydrogen-bonding scheme in triglycine sulphate. (TGS), which is an important hydrogen bonded ferroelectric, a single crystal neutron diffraction study was undertaken. The structure was refined to an R-factor of R[F2] = 0.034. Earlier neutron structure of TGS was reported with a very limited ...

  18. Neutron diffraction measuring technique. A diffractometer for stress characterization

    International Nuclear Information System (INIS)

    Ceretti, M.; Lodini, A.

    1996-01-01

    The principles of the neutron diffraction technique for the characterization of stresses in materials, are presented and the two neutron generation techniques (high flux nuclear reactors and neutron spallation sources) are described together with the apparatus (monochromator, sample line, detectors (mainly 3 He detectors)); recommendations concerning alignment and positioning of the sample and sensor, determination of the reference distance, uncertainties on deformation values, are discussed

  19. Magnetization and neutron diffraction studies on FeCrP

    Indian Academy of Sciences (India)

    TN = 280 (±10) K. Preliminary analysis of neutron diffraction pattern at 13 K is indicative of a rather complicated magnetic ... [5]. Structural characterization has been done using powder X-ray diffraction (XRD) on Philips make diffractometer .... as compared to the pattern in the paramagnetic state. This is suggestive of a very.

  20. Investigation of Acrylic Acid at High Pressure using Neutron Diffraction

    DEFF Research Database (Denmark)

    Johnston, Blair F.; Marshall, William G.; Parsons, Simon

    2014-01-01

    This article details the exploration of perdeuterated acrylic acid at high pressure using neutron diffraction. The structural changes that occur in acrylic acid-d4 are followed via diffraction and rationalised using the Pixel method. Acrylic acid undergoes a reconstructive phase transition to a new...

  1. Comparative study of structural properties of trehalose water solutions by neutron diffraction, synchrotron radiation and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Cesaro, A.; Magazu, V.; Migliardo, F.; Sussich, F.; Vadala, M

    2004-07-15

    Neutron diffraction measurements combined with H/D substitution have been performed on trehalose aqueous solutions as a function of temperature and concentration by using the SANDALS diffractometer at ISIS Facility (UK). The findings point out a high capability of trehalose to strongly affect the tetrahedral hydrogen bond network of water. The neutron diffraction results are also compared with simulation and experimental data obtained by synchrotron radiation on the phospholipid bilayer membranes (DPPC)/trehalose/H{sub 2}O ternary system.

  2. A note on the limitations of the magnetic axis direction determination by neutron powder diffraction

    International Nuclear Information System (INIS)

    Shaked, Hagai

    2004-01-01

    Rotation crystal symmetry analysis of the magnetic intensities in neutron powder diffraction from magnetically ordered, collinear structures is performed. This analysis, making no reference to a specific crystal system, leads to the well-known limitations on the direction of magnetic axis determination by neutron powder diffraction. It shows that due to the second-order dependence of the magnetic intensity on the magnetic axis components, these limitations result solely from the crystal rotation symmetry in the magnetically ordered state

  3. Neutron diffraction, structural inorganic chemistry and high-temperature superconductors

    International Nuclear Information System (INIS)

    Hewat, A.W.

    1992-01-01

    This paper discusses neutron diffraction which has been of fundamental importance for the determination of the structure of high-temperature superconductors and for understanding the influence of structure on the critical temperature. This is because the new superconductors are heavy metal oxides; X-rays are mainly scattered by the metal atoms, but thermal neutrons are scattered as strongly by oxygen, which is the atom of most interest in these materials. In fact, for the past 20 yr, neutron diffraction has been steadily gaining ground as an important technique in structural inorganic chemistry

  4. Diffraction of very cold neutrons at phase gratings

    Science.gov (United States)

    Eder, Kurt; Gruber, Manfred; Zeilinger, Anton; Gähler, Roland; Mampe, Walter

    1991-06-01

    We report extensive experiments on the diffraction of very cold neutrons ( λ ≈ 100 Å) at large-area transmission phase gratings with grating constants d = 2 μm and d = 1 μm, respectively. The experimental results are compared with Fresnel-Kirchhoff calculations showing agreement in great detail. Using phase gratings it is possible to shift intensities between different diffraction orders, thus making them very useful for other neutron-optics experiments at low energies. Also, the excellent manufacturing precision of our transmission phase gratings meets the requirements for such experiments like very-cold-neutron interferometry.

  5. Diffraction of very cold neutrons at phase gratings

    International Nuclear Information System (INIS)

    Eder, K.; Gruber, M.; Zeilinger, A.; Gaehler, R.; Mampe, W.

    1991-01-01

    We report extensive experiments on the diffraction of very cold neutrons (λ ≅ 100A) at large-area transmission phase gratings with grating constants d=2μm and d=1μm, respectively. The experimental results are compared with Fresnel-Kirchhoff calculations showing agreement in great detail. Using phase gratings it is possible to shift intensities between different diffraction orders, thus making them very useful for other neutron-optics experiments at low energies. Also, the excellent manufacturing precision of our transmission phase gratings meets the requirements for such experiments like very-cold-neutron interferometry. (orig.)

  6. Dynamical effect in small-angle neutron diffraction from membranes

    International Nuclear Information System (INIS)

    Caspar, D.L.D.; Phillips, W.C.

    1976-01-01

    It has been suggested that multilayers with large repeat periods, fabricated by evaporating alternating thin films of two metals with high scattering-density contrast, could be used as efficient wide-band pass monochromators for x-rays and neutrons. In the limit of a large number of weakly reflecting, periodically arranged layers, the analysis gives results corresponding to those of the dynamical theory for diffraction of x-rays and neutrons from perfect crystals. Measurement of dynamical neutron diffraction effects from membrane arrays provides significant information about the order in the packing and the absolute scattering-density difference between layers

  7. Texture investigations of natural rock salt using neutron diffraction

    International Nuclear Information System (INIS)

    Ertel, A.

    1987-01-01

    The main benefits and constraints are described of X-ray and neutron diffraction. Tabulated are diffraction factors and absorption coefficients of Na, Cl, K, S, O, Ca and Mg for both methods and a comparison is made of neutron and X-ray penetration depths at 50% absorption for halite, sylvine, polyhalite, kieserite, anhydrite and hematite. Neutron diffraction was used for the study of preferred orientation in halite from mines in Zielitz (GDR), Bleicherode (GDR) and Werra (GDR). The experiments were carried out at the research reactor at ZfK Rossendorf, GDR. Samples were irradiated with a flux density of monochromatic thermal neutrons of 10 8 n.cm -2 s -1 . Measured were (200), (220) and (222) pole figures of halite. In the samples from Zielitz and Bleicherode a (100) fibre texture was found, in samples from Werra a (110) fibre texture. (E.S.) 23 refs., 11 figs., 2 tabs

  8. Structural observation of amorphous alloys by neutron diffraction

    International Nuclear Information System (INIS)

    Fukunaga, Toshiharu; Itoh, Keiji

    2006-01-01

    Neutron diffraction is a powerful tool to elucidate the atomic arrangement of amorphous alloys because of characteristic scattering lengths of constituent elements. For hydrogen absorption amorphous alloys H/D isotopic substitution was employed to observe the location of deuterium atoms because the neutron coherent scattering length of deuterium is large enough to observe in comparison with those of the constituent atoms. Moreover, Reverse Monte Carlo (RMC) modeling has been recognized to be an excellent method for visualizing the three-dimensional atomic arrangement of amorphous alloys, based on the results of neutron and X-ray diffraction experiments. Therefore, the combination of neutron, X-ray diffraction experiments and the RMC modeling was used to clarify the topological characteristics of the structure of amorphous alloys. (author)

  9. High temperature neutron diffraction study of LaPO4

    International Nuclear Information System (INIS)

    Mishra, S.K.; Mittal, R.; Ningthoujam, R.S.; Vatsa, R.K.; Hansen, T.

    2016-01-01

    We report high temperature powder neutron diffractions study in LaPO 4 using high-flux D20 neutron diffractometer in the Institut Laue-Langevin, France. The measurements were carried out in high resolution mode (incident neutron wavelength 1.36 A) at various temperature upto 900°C. CarefuI inspection of temperature dependence of diffraction data showed appearance and disappearance of certain Bragg's reflections above 1273 K. It is a signature of structural phase transition. Rietveld refinement of the powder diffraction data revealed that diffraction patterns at and above 800°C could be indexed using the monoclinic structure with P21/n space group. Detail analysis for identify the water molecules is under investigation. (author)

  10. The progress of neutron powder diffraction in J-PARC

    International Nuclear Information System (INIS)

    Ishigaki, Toru

    2007-01-01

    Ibaraki prefecture, the local government of the area for J-PARC site, has decided to build a versatile powder diffractometer (IBARAKI Materials Design Diffractometer) to promote industrial applications for neutron beams in J-PARC. This diffractometer is designed to be a high throughput one enabling materials scientists to use it like the chemical analytical instruments in their material development processes. It covers in d range 0.18 < d(A) < 2.5 with d/d=0.16% at the high resolution scattering detector bank, and covers 2.5 < d(A) < 400 with gradually changing resolution with the standard mode. Typical measurement time to obtain a 'Rietveld-quality' data is several minutes for the sample size of laboratory X-ray diffractometer. To promote industrial application, a utilization system for this diffractometer is required. We will establish a support system for both academic and industrial users who are willing to use neutron but have not been familiar with neutron diffraction. (author)

  11. Ultra high resolution neutron scattering: Neutron Resonance Spin-Echo and Larmor Diffraction

    Science.gov (United States)

    Walters, Andrew; Keller, Thomas; Keimer, Bernhard

    2012-02-01

    The TRISP spectrometer at the FRM II neutron source near Munich, Germany, is a unique world-leading neutron scattering instrument which employs the Neutron Resonance Spin-Echo technique (NRSE). Linewidths of dispersive excitations with energy transfers up to 50 meV can be measured with an energy resolution in the μeV range without the restrictive flux limitations that normally apply to high resolution neutron triple-axis spectrometers. Pioneering studies on the electron-phonon interaction in elemental superconductorsootnotetextP. Aynajian et al., Science 319 1509 (2008) and the lifetimes of magnetic excitations in archetypal magnetic systems will be reviewed.ootnotetextS. Bayrakci et al., Science 312 1928 (2006) The instrument can also be used as a Larmor diffractometer, enabling d-spacings to be measured with a resolution of δdd ˜10-6, i.e. more than one order of magnitude more sensitive than conventional diffraction techniques.ootnotetextC. Pfleiderer et al., Science 316 1871 (2007) Ongoing and future NRSE and Larmor diffraction projects will be outlined, especially in regard to prospective studies which will take full advantage of the new low temperature and high pressure sample environment capabilities now available at TRISP.

  12. X-ray diffraction, neutron diffraction and analysis of molecular structures

    International Nuclear Information System (INIS)

    Fontecilla-Camps, J.C.

    1997-01-01

    The only method that is capable to show the atomic structure of most of macromolecules is the X ray diffraction; neutron diffraction is mostly used for the localization of hydrogen atoms, too light to be detected by X ray diffraction. With the growing number of known structures, the molecular crystallographic study may combine the molecular replacement technique and the co-crystallization method, or use the new Laue method, and leads to the functional and topological analysis of biological molecular structures

  13. Neutron diffraction and optics in noncentrosymmetric crystals New feasibility of a search for neutron EDM

    International Nuclear Information System (INIS)

    Fedorov, V.V.; Voronin, V.V.

    2003-01-01

    Recently strong electric fields (up to 10 9 V/cm) have been discovered, which affect the neutrons moving in noncentrosymmetric crystals. Such fields allow for new polarization phenomena in the neutron diffraction and in the optics and provide, for instance, a new method of a search for the neutron electric dipole moment (EDM). A strong interplanar electric field of the crystal and a sufficiently long time for the neutron passage through the crystal for Bragg angle close to π/2 in the case of Laue diffraction make it possible to exceed the sensitivity achieved with the magnetic resonance method using ultra cold neutrons (UCN method). The pilot setup has been created and mounted at the neutron beam at the WWR-M reactor in Gatchina. It allows to study the optics and the dynamical diffraction of polarized neutrons in thick (1-10 cm) crystals, using the direct diffraction beam and Bragg angles close to 90 deg. . The first experimental results are discussed on observing new effects in both the Laue diffraction and the optics of cold neutrons. These results confirm the opportunity to increase more than by an order of magnitude the sensitivity of the method to neutron EDM, using the diffraction angles close to 90 deg. and give a real prospect to exceed the sensitivity of the UCN method

  14. Extinction correction in white X-ray and neutron diffraction

    International Nuclear Information System (INIS)

    Tomiyoshi, S.; Yamada, M.; Watanabe, H.

    1980-01-01

    Extinction effects in white-beam X-ray and neutron diffraction are considered. In white-beam diffraction, a small deviation of the wavelength from the Bragg condition Δlambda is a variable which represents the line profile of the diffraction peaks, so that by using the new parameter Δlambda the theory is converted to one in white-beam diffraction. It is shown that for a convex crystal, primary extinction agrees with the results calculated already for monochromatic diffraction. The same relation is shown to hold in secondary extinction. It is concluded that extinction theory derived for monochromatic diffraction is applicable without any modification in white-beam diffraction. (Auth.)

  15. Lattice strain measurement in rock sample by neutron diffraction technique

    International Nuclear Information System (INIS)

    Abe, Jun; Ito, Takayoshi; Sekine, Kotaro; Harjo, Stefanus; Aizawa, Kazuya

    2015-01-01

    Strain gauge and mechanical extensometers are commonly used to measure strain in rock samples. In recent years, diffraction techniques with X-rays and neutrons for investigating strain in engineering materials have been developed. Strain measurements using diffraction technique are based on Bragg's law. Lattice spacing changes with strain, which induces peak shift of Bragg peak. Strain value can be estimated from this peak shift value. Strain measurements using the world's highest intensity neutron beam can be performed at Japan Proton Accelerator Research Complex (J-PARC) constructed at Tokai in Ibaraki. Neutron powder diffractometer dedicating to investigate strain state in engineering materials has been constructed at BL19 in J-PARC, which is named as The Engineering Materials Diffractometer 'TAKUMI'. In order to examine applicability of the diffractometer to rock materials, in situ neutron diffraction experiments on rock samples under uni-axial compression have been performed. Higher resolution strain data has been obtained in shorter time compared to other diffractometers. In addition, neutron diffraction peaks of not only major component, such as quartz, but also minor components, such as feldspars, could be observed. Anisotropy of strain with respect to the quartz crystal orientation and discrepancy between macroscopic strain (measured by strain gauge) and lattice strain (measured by neutron diffraction) were also recognized. Change in peak width with respect to stress magnitude showed a different behavior depending on rock type. Strain measurements using neutron diffraction technique give us new insight in rock deformation which cannot be obtained by common technique. (author)

  16. Study of the ZrCr0.7Ni1.3 multiphased system under hydrogen pressure by in-situ neutron diffraction

    International Nuclear Information System (INIS)

    Bououdina, M.; Soubeyroux, J.L.; Fruchart, D.

    2000-01-01

    Both X-ray and neutron diffraction Rietveld analyses show that the as-cast ZrCr 0.7 Ni 1.3 alloy crystallises with the C15-type Laves phase type structure, with the presence of >30 wt.% Zr 7 Ni 10 and a few weight percent chromium. After annealing at 1373 K, we observed the disappearance of chromium metal and a reduction by more than half of Zr 7 Ni 10 . P-C-T measurements performed on the as-cast material show an absorption capacity of about 0.9 H/AB 2 at 323 K and under P=10 bar. In-situ neutron diffraction experiments performed at 323 K under deuterium gas pressure reveal that, after full hydrogenation of the sample, the Zr 7 Ni 10 phase transforms into an amorphous phase, but recrystallises under vacuum when the temperature is raised above 373 K. (orig.)

  17. European standardization activities on residual stress analysis by neutron diffraction

    CERN Document Server

    Youtsos, A G

    2002-01-01

    A main objective of a recently completed European research project, RESTAND - residual stress standard using neutron diffraction, was to develop industrial confidence in the application of the neutron-diffraction technique for residual stress measurement and its principal deliverable was a relevant draft code of practice. In fact this draft standard was jointly developed within RESTAND and VAMAS TWA 20 - an international pre-normative research activity. As no such standard is yet available, on the basis of this draft standard document the European Standards Committee on Non-Destructive Testing (CEN TC/138) has established a new ad hoc Work Group (AHG7). The objective of this group is the development of a European pre-standard on a 'test method for measurement of residual stress by neutron diffraction'. The document contains the proposed protocol for making the measurements. It includes the scope of the method, an outline of the technique, the calibration and measurement procedures recommended, and details of ...

  18. High resolution neutron Larmor diffraction using superconducting magnetic Wollaston prisms.

    Science.gov (United States)

    Li, Fankang; Feng, Hao; Thaler, Alexander N; Parnell, Steven R; Hamilton, William A; Crow, Lowell; Yang, Wencao; Jones, Amy B; Bai, Hongyu; Matsuda, Masaaki; Baxter, David V; Keller, Thomas; Fernandez-Baca, Jaime A; Pynn, Roger

    2017-04-13

    The neutron Larmor diffraction technique has been implemented using superconducting magnetic Wollaston prisms in both single-arm and double-arm configurations. Successful measurements of the coefficient of thermal expansion of a single-crystal copper sample demonstrates that the method works as expected. The experiment involves a new method of tuning by varying the magnetic field configurations in the device and the tuning results agree well with previous measurements. The difference between single-arm and double-arm configurations has been investigated experimentally. We conclude that this measurement benchmarks the applications of magnetic Wollaston prisms in Larmor diffraction and shows in principle that the setup can be used for inelastic phonon line-width measurements. The achievable resolution for Larmor diffraction is comparable to that using Neutron Resonance Spin Echo (NRSE) coils. The use of superconducting materials in the prisms allows high neutron polarization and transmission efficiency to be achieved.

  19. Neutron and x-ray diffraction studies of liquids and glasses

    International Nuclear Information System (INIS)

    Fischer, Henry E; Barnes, Adrian C; Salmon, Philip S

    2006-01-01

    The techniques of neutron diffraction and x-ray diffraction, as applied to structural studies of liquids and glasses, are reviewed. Emphasis is placed on the explanation and discussion of the experimental techniques and data analysis methods, as illustrated by the results of representative experiments. The disordered, isotropic nature of the structure of liquids and glasses leads to special considerations and certain difficulties when neutron and x-ray diffraction techniques are applied, especially when used in combination on the same system. Recent progress in experimental technique, as well as in data analysis and computer simulation, has motivated the writing of this review

  20. Neutron diffraction measurements of residual stresses in NPP construction materials

    International Nuclear Information System (INIS)

    Hinca, R.; Bokuchava, G.

    2001-01-01

    Neutron diffraction is one of the most powerful methods for condensed matter studies. This method is used for non-destructive determination of residual stresses in material. The fundamental aspects of neutron diffraction are discussed, together with a brief description of the experimental facility. The principal advantage of using neutrons rather than the more conventional X-rays is the fact that neutron can penetrate deeply (2-4 cm for steel and more than 10 cm for aluminium) into metals to determine internal parameters within the bulk of materials. We present results of measurements residual stresses in NPP construction material - austenitic stainless steel (Cr-18%, Ni-10%, Ti-1%) coated with high-nickel alloy. (authors)

  1. Texture and structure analysis of metagabbro by neutron diffraction

    Czech Academy of Sciences Publication Activity Database

    Kalvoda, L.; Vratislav, S.; Dlouhá, M.; Krůželová, M.; Machek, Matěj

    2012-01-01

    Roč. 340, č. 1 (2012), 012107/1-012107/6 ISSN 1742-6588. [European Conference on Neutron Scattering (ECNS)/5./. Prague, 17.07.2011-21.07.2011] R&D Projects: GA ČR GA205/08/0767 Institutional research plan: CEZ:AV0Z30120515 Keywords : neutron diffraction method * metagabbro * Bohemian Massif Subject RIV: DB - Geology ; Mineralogy

  2. High-pressure neutron diffraction studies at LANSCE

    International Nuclear Information System (INIS)

    Zhao, Yusheng; Zhang, Jianzhong; Xu, Hongwu; Lokshin, Konstantin A.; He, Duanwei; Qian, Jiang; Pantea, Cristian; Daemen, Luke L.; Vogel, Sven C.; Ding, Yang; Xu, Jian

    2010-01-01

    The development of neutron diffraction under extreme pressure (P) and temperature (T) conditions is highly valuable to condensed matter physics, crystal chemistry, materials science, and earth and planetary sciences. We have incorporated a 500-ton press TAP-98 into the HiPPO diffractometer at the Los Alamos Neutron Science Center (LANSCE) to conduct in situ high-P-T neutron diffraction experiments. We have developed a large gem-crystal anvil cell, ZAP, to conduct neutron diffraction experiments at high P. The ZAP cell can be used to integrate multiple experimental techniques such as neutron diffraction, laser spectroscopy, and ultrasonic interferometry. More recently, we have developed high-P low-T gas/liquid cells in conjunction with neutron diffraction. These techniques enable in situ and real-time examination of gas uptake/release processes and allow accurate, time-dependent determination of changes in crystal structure and related reaction kinetics. We have successfully used these techniques to study the equations of state, structural phase transitions, and thermo-mechanical properties of metals, ceramics, and minerals. We have conducted researches on the formation/decomposition kinetics of methane, CO 2 and hydrogen hydrate clathrates, and hydrogen/CO 2 adsorption of inclusion compounds such as metal-organic frameworks (MOFs). The aim of our research is to accurately map out phase relations and determine structural parameters (lattice constants, atomic positions, atomic thermal parameters, bond lengths, bond angles, etc.) in the P-T-X space. We are developing further high-P-T technology with a new 2000-ton press, TAPLUS-2000, and a ZIA (Deformation-DIA type) cubic anvil package to routinely achieve pressures up to 20 GPa and temperatures up to 2000 K. The design of a dedicated high-P neutron beamline, LAPTRON, is also underway for simultaneous high-P-T neutron diffraction, ultrasonic, calorimetry, radiography, and tomography studies. Studies based on high

  3. Applications of neutron powder diffraction in materials research

    International Nuclear Information System (INIS)

    Kennedy, S.J.

    1996-01-01

    The aim of this article is to provide an overview of the applications of neutron powder diffraction in materials science. The technique is introduced with particular attention to comparison with the X-ray powder diffraction technique to which it is complementary. The diffractometers and special environment ancillaries operating around the HIFAR research reactor at the Australian Nuclear Science and Technology Organisation (ANSTO) are described. Applications of the technique which the advantage of the unique properties of thermal neutrons have been selected from recent materials studies undertaken at ANSTO

  4. Thermal neutron diffraction on two-dimensional lattices

    International Nuclear Information System (INIS)

    Stern, T.

    1974-06-01

    This thesis deals with the problem of neutron diffraction from a two-dimensional lattice. The neutron spin is not taken into account. Firstly the scalar wave field is treated by means of differential equations (Helmholtz) and secondly by the equivalent integral equation formulation (Kirchoff-Weber). Finally, using the methods of the Green function, the reflected and transmitted wave fields are represented as integral transformations of a certain source function. In respect to the calculation of the amplitudes of the diffraction waves the third method seems to be the best one for the purpose of the physical interpretation and the applicability of numerical methods. (C.R.)

  5. Maximizing Macromolecule Crystal Size for Neutron Diffraction Experiments

    Science.gov (United States)

    Judge, R. A.; Kephart, R.; Leardi, R.; Myles, D. A.; Snell, E. H.; vanderWoerd, M.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    A challenge in neutron diffraction experiments is growing large (greater than 1 cu mm) macromolecule crystals. In taking up this challenge we have used statistical experiment design techniques to quickly identify crystallization conditions under which the largest crystals grow. These techniques provide the maximum information for minimal experimental effort, allowing optimal screening of crystallization variables in a simple experimental matrix, using the minimum amount of sample. Analysis of the results quickly tells the investigator what conditions are the most important for the crystallization. These can then be used to maximize the crystallization results in terms of reducing crystal numbers and providing large crystals of suitable habit. We have used these techniques to grow large crystals of Glucose isomerase. Glucose isomerase is an industrial enzyme used extensively in the food industry for the conversion of glucose to fructose. The aim of this study is the elucidation of the enzymatic mechanism at the molecular level. The accurate determination of hydrogen positions, which is critical for this, is a requirement that neutron diffraction is uniquely suited for. Preliminary neutron diffraction experiments with these crystals conducted at the Institute Laue-Langevin (Grenoble, France) reveal diffraction to beyond 2.5 angstrom. Macromolecular crystal growth is a process involving many parameters, and statistical experimental design is naturally suited to this field. These techniques are sample independent and provide an experimental strategy to maximize crystal volume and habit for neutron diffraction studies.

  6. Investigation of Acrylic Acid at High Pressure Using Neutron Diffraction

    OpenAIRE

    Johnston, Blair F.; Marshall, William G.; Parsons, Simon; Urquhart, Andrew J.; Oswald, Iain D. H.

    2014-01-01

    This article details the exploration of perdeuterated acrylic acid at high pressure using neutron diffraction. The structural changes that occur in acrylic acid-d4 are followed via diffraction and rationalized using the Pixel method. Acrylic acid undergoes a reconstructive phase transition to a new phase at ∼0.8 GPa and remains molecular to 7.2 GPa before polymerizing on decompression to ambient pressure. The resulting product is analyzed via Raman and FT-IR spectroscopy and differential scan...

  7. New in-situ neutron diffraction cell for electrode materials

    OpenAIRE

    Biendicho, Jordi Jacas; Roberts, Matthew; Offer, Colin; Noréus, Dag; Widenkvist, Erika; Smith, Ronald I.; Svensson, Gunnar; Edström, Kristina; Norberg, Stefan T.; Eriksson, Sten G.; Hull, Stephen

    2014-01-01

    A novel neutron diffraction cell has been constructed to allow in-situ studies of the structural changes in materials of relevance to battery applications during charge/discharge cycling. The new design is based on the coin cell geometry, but has larger dimensions compared to typical commercial batteries in order to maximize the amount of electrode material and thus, collect diffraction data of good statistical quality within the shortest possible time. An important aspect of the design is it...

  8. The structure of pumice by neutron diffraction

    International Nuclear Information System (INIS)

    Floriano, M.A.; Venezia, A.M.; Deganello, G.; Svensson, E.C.; Root, J.H.

    1994-01-01

    Small-angle neutron scattering (SANS) and wide-angle neutron scattering (WANS) measurements on pumice, an amorphous natural aluminosilicate used as support for metals in the preparation of catalysts, are reported. The SANS spectrum indicates the presence of a broad size distribution of pores and the absence of volume fractality. Surface fractality, however, cannot be ruled out. The structure of pumice, suggested by the pair-correlation function derived from the WANS spectrum and simulated by a random-network structure model, is very similar to that of vitreous silica, consisting mainly of SiO 4- 4 tetrahedra interconnected by bridging O atoms with additional local disorder generated by the replacement, on average, of one in ten Si atoms by aluminium. (orig.)

  9. Investigation of melts and amorphous substances by means of neutron diffraction

    International Nuclear Information System (INIS)

    Steeb, S.; Lamparter, P.

    1979-01-01

    A review is given concerning the application of neutrons for structural investigations with melts and amorphous substances. The treatment of neutron diffraction as equivalent of X-ray or electron diffraction is followed by the discussion of the different possibilities of combination of X-ray and neutron diffraction as well as the method of isotopic substitution. Finally magnetic neutron diffraction and inelastic neutron scattering is treated. (orig.) [de

  10. Neutron diffraction residual strain / stress measurements

    International Nuclear Information System (INIS)

    Paradowska, Anna

    2012-01-01

    Residual stresses affect mechancial properties of materials and prodcuts, it is essential to estimate them practically in order to esatblish acceptable limits. Knowledge of the development of residual stresses in components at the various production stages- extrusion, rolling, machining, welding and heat treating-can be used to imporve product reliability and performance. This short article gives an example relevant to the power industry using ANSTO's 'Kowari' neutron strain scanner.

  11. Neutron diffraction and reflection studies of superconductors

    International Nuclear Information System (INIS)

    Reynolds, J.M.

    1998-01-01

    I have studied two magnetic properties of superconductors using different neutron scattering techniques. Due to their magnetic moment and lack of electrical charge, neutrons can provide an extremely sensitive probe into magnetism on a small scale. Unusual magnetic structures have previously been observed in the non-superconducting PrBa 2 Cu 3 O 6+δ , in particular showing a coupling between the rare-earth and the Cu-O 2 planes. For comparison, I have used elastic neutron scattering to measure the temperature dependent magnetic structure of the high-T c superconductor NdBa 2 Cu 3 O 7 , and its nonsuperconducting reduced form NdBa 2 Cu 3 O 6 . The magnetic structures of both the Nd and Cu sub-lattices axe presented. Measurements axe shown for single crystals of both the oxygenated and reduced form, and also for a non-stoichiometric single crystal with Nd substituted on the Ba sites. I present a quantitative analysis of the magnetic moments, with account taken of the instrumental resolution including sample mosaicity and intrinsic peak shapes. No evidence was found for any coupling of the type seen in PrBa 2 Cu 3 O 6+δ . Many of the underlying properties of superconductors are evidenced in the way magnetic fields are excluded in the different states. I have used polarized neutron reflectometry to measure the magnetic field profile in thin film superconductors. I present measurements for pure niobium and preliminary measurements for YBa 2 Cu 3 O 7 . The samples studied are much thicker than those previously measured, to provide a closer match to the bulk superconductor properties and allow meaningful measurements of the higher field states. For niobium, the applied field dependence is measured for fields covering the Meissner and mixed states, and models are compared for these states and the surface superconductivity state. (author)

  12. Bragg diffraction optics in neutron diffractometry

    Czech Academy of Sciences Publication Activity Database

    Mikula, Pavol; Kulda, Jiří; Lukáš, Petr; Ono, M.; Šaroun, Jan; Vrána, Miroslav; Wagner, V.

    2000-01-01

    Roč. 283, - (2000), s. 289-294 ISSN 0921-4526. [NOP99 Workshop "Neutron Optics in the Next Millenium 99". Villigen, 25.11.1999-27.11.1999] R&D Projects: GA ČR GV202/97/K038; GA AV ČR IAA1048003; GA AV ČR KSK1048601 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.893, year: 2000

  13. High pressure neutron powder diffraction at LANSCE

    International Nuclear Information System (INIS)

    Von Dreele, R.B.

    1994-01-01

    By making use of the recently developed ''Paris-Edinburgh'' high pressure cell, the author has successfully performed neutron powder experiments to 10GPa at ambient temperature. Results for the structural compression of the high Tc 1223-Hg superconductor to 9.2 GPa, the compression and possible hydrogen bond formation in brucite, Mg(OD) 2 , to 9.3 GPa, and the molecular reorientation in nitromethane to 5.5 GPa will be presented

  14. Diffraction plane dependence of elastic constants in residual stress measurement by neutron diffraction

    International Nuclear Information System (INIS)

    Okido, Shinobu; Hayashi, Makoto; Morii, Yukio; Minakawa, Nobuaki; Tsuchiya, Yoshinori

    1997-01-01

    In a residual stress measurement by x-ray diffraction method and a neutron diffraction method, strictly speaking, the strain measurement of various diffracted surface was conducted and it is necessary to use its elastic modulus to convert from the strain to the stress. Then, in order to establish the residual stress measuring technique using neutron diffraction, it is an aim at first to make clear a diffraction surface dependency of elastic modulus for the stress conversion in various alloys. As a result of investigations the diffraction surface dependency of elastic module on SUS304 and STS410 steels by using RESA (Neutron diffractometer for residual stress analysis) installed at JRR-3M in Tokai Establishment of JAERI, following results are obtained. The elastic modulus of each diffraction surface considering till plastic region could be confirmed to be in a region of ±20% of that calculated by Kroner's model and to be useful for that used on conversion to the stress. And, error of this elastic modulus was thought to cause the transition and defect formed at inner portion of the materials due to a plastic deformation. (G.K.)

  15. Internal strain measurement using pulsed neutron diffraction at LANSCE

    International Nuclear Information System (INIS)

    Goldstone, J.A.; Bourke, M.A.M.; Shi, N.

    1994-01-01

    The presence of residual stress in engineering components can effect their mechanical properties and structural integrity. Neutron diffraction in the only technique that can make nondestructive measurements in the interior of components. By recording the change in crystalline lattice spacings, elastic strains can be measured for individual lattice reflections. Using a pulsed neutron source, all lattice reflections are recorded in each measurement, which allows for easy examination of heterogeneous materials such as metal matrix composites. Measurements made at the Manuel Lujan Jr. Neutron Scattering Center (LANSCE) demonstrate the potential at pulsed sources for in-situ stress measurements at ambient and elevated temperatures

  16. Possible standard specimens for neutron diffraction residual stress measurements

    International Nuclear Information System (INIS)

    Brand, P.C.; Prask, H.J.; Fields, R.J.; Blackburn, J.; Proctor, T.M.

    1995-01-01

    Increasingly, sub-surface residual stress measurements by means of neutron diffraction are being conducted at various laboratories around the world. Unlike X-ray diffraction residual stress measurement setups, neutron instruments in use worldwide vary widely in design, neutron flux, and level of dedication towards residual stress measurements. Although confidence in the neutron technique has increased within the materials science and engineering communities, no demonstration of standardization or consistency between laboratories has been made. One of the steps in the direction of such standardization is the development of standard specimens, that have well characterized residual stress states and which could be examined worldwide. In this paper the authors will examine two options for a neutron stress standard specimen: (1) a steel ring-plug specimen with very well defined diametrical interference; (2) a spot weld in a High Strength Low Alloy steel disk. The results of neutron residual stress measurements on these specimens will be discussed and conclusions as to their usefulness as neutron stress standards will be presented

  17. Neutron Diffraction Studies of Nuclear Magnetic Ordering in Copper

    DEFF Research Database (Denmark)

    Jyrkkiö, T.A.; Huiku, M.T.; Siemensmeyer, K.

    1989-01-01

    We have constructed a two-stage nuclear demagnetization cryostat for neutron diffraction studies of nuclear magnetism in copper. The cryostat is combined with a two-axis neutron spectrometer which can use both polarized and unpolarized neutrons. By demagnetizing highly polarized copper nuclear...... spins, the nuclei could be cooled below the ordering temperatureT N≃60 nK, while keeping the lattice at a considerably higher temperature between 50 and 100 µK. The neutron beam increases the lattice temperature in the sample by a factor of two or more, thereby considerably shortening the time...... for measurements in the ordered state; both our calculations and the experiments yield 1 nW beam heating. Polarized neutron experiments show that the scattered intensities from the strong fcc reflections are severely reduced by extinction. This makes the sample not very suitable for further studies with polarized...

  18. Bragg diffraction optics in neutron diffractometry

    Czech Academy of Sciences Publication Activity Database

    Mikula, Pavol; Vrána, Miroslav; Furusaka, M.; Wagner, Vladimír; Choi, YN.; Moon, MK.; Em, V.; Lee, Ch.

    2004-01-01

    Roč. 529, č. 1 (2004), s. 138-147 ISSN 0168-9002 R&D Projects: GA ČR GA202/03/0891; GA AV ČR IAA1048003; GA MŠk OC P7.003 Institutional research plan: CEZ:AV0Z1048901 Keywords : neuron diffracton * Bragg diffraction optics * Bent perfect crystal Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.349, year: 2004

  19. Structural changes in tetracyanoethylene at high pressures: neutron diffraction study

    International Nuclear Information System (INIS)

    Mukhopadhyay, R.; Chaplot, S.L.

    2002-01-01

    We report on structural changes in monoclinic tetracyanoethylene, C 2 (CN) 4 as studied by in situ high-pressure (0-5 GPa) neutron powder diffraction experiments. Structural parameters were obtained by Rietveld profile refinement of the diffraction pattern up to P=2.5 GPa. Above this pressure the width parameter is found to diverge, indicating pressure-induced disordering at 2.5 GPa. The recovered sample, on release of pressure from 5 GPa, is found to have transformed to a graphite-like amorphous structure. The transformation to a graphite-like material has been verified by an independent high-pressure x-ray diffraction experiment. (author)

  20. Diffraction on disordered materials using 'neutron-like' photons

    DEFF Research Database (Denmark)

    Neuefeind, J.; Poulsen, H.F.

    1995-01-01

    In the past photon diffraction has been carried out mainly using the characteristic radiation from X-ray tubes in the energy range from about 8-20 keV. Comparison of these experiments with neutron diffraction results is difficult since in this energy range the photoelectric absorption...... is the predominant process. The photoelectric absorption decreases with lambda(3), so increasing the energy to about 100 keV has a drastic effect on the absorption coefficient. Photons in the high energy rang can be obtained conveniently from modern synchrotron sources. High energy photon diffraction has additional...

  1. 3DXRD microscopy - a comparison with neutron diffraction

    DEFF Research Database (Denmark)

    Poulsen, H.F.

    2002-01-01

    of the technique is presented and the potential for in situ processing studies illustrated. The hard-X-ray method is compared to conventional neutron-diffraction techniques: texture and strain measurements, small-angle scattering, and in situ powder diffraction.......3DXRD microscopy is a novel tool for fast and non-destructive characterisation of the individual grains and sub-grains inside bulk materials (powders or polycrystals). The method is based on diffraction with hard X-rays (E > 50 keV), enabling 3D studies of millimeter to centimeter-thick specimens...

  2. Analysis of minor phase with neutron diffraction technique

    International Nuclear Information System (INIS)

    Engkir Sukirman; Herry Mugirahardjo

    2014-01-01

    The presence of minor phases in a sample have been analyzed with the neutron diffraction technique. In this research, the sample of Fe nanoparticles (FNP) has been selected as the object of case study. The first step was to prepare the FNP sample with the ball milling technique. Hereinafter, the sample of milling result was referred FIC2. The presence of phases formed in FIC2 were analyzed qualitatively and quantitatively using the high resolution neutron diffraction (HRPD ) and X-Ray Diffraction (XRD) techniques. The diffraction data were analyzed by means of the Rietveld method utilizing a computer code, namely FullProf and performed by referring to the supporting data, namely particle size and magnetic properties of materials. The two kinds of supporting data were obtained from the PSA (Particles Size Analyzer) and VSM (Vibrating Samples Magnetometer), respectively. The analysis result shows that quality of fitting for neutron diffraction pattern is better than the fitting quality for x-ray diffraction pattern. Of the HRPD data were revealed that FIC2 consists of Fe, γFe 2 O 3 and Fe 3 O 4 phases as much as 78.62; 21.37 and 0.01%, respectively. Of the XRD data were obtained that FIC2 consists of Fe and γFe 2 O 3 phases with amount of 99.96 and 0.04%, respectively; the presence of Fe 3 O 4 phase was not observed. With the neutron diffraction technique, the presence of minor phase can be determined accurately. (author)

  3. High Pressure Apparatus for Angle Dispersive Neutron Diffraction

    OpenAIRE

    Kazuo, Kamigaki; Takejiro, Kaneko; Shunya, Abe; Masayoshi, Ohashi

    1983-01-01

    A piston-cylinder type high pressure apparatus was designed for the angle dispersive neutron diffraction. A Ti-53wt% Zr alloy was used for the cylinder. The performance was tested by observing the structural transformation under pressure in RbBr from an NaCl-type to a CsCl-type.

  4. Zinc (tris) thiourea sulphate (ZTS): A single crystal neutron diffraction ...

    Indian Academy of Sciences (India)

    near IR laser radiations. In this study, the crystal structure of ZTS has been ob- tained in detail by single crystal neutron diffraction technique. Using the structural parameters and an existing formalism [1] based on the theory of bond polarizability, the contributions from each of the structural groups in the unit cell to the total.

  5. Frontline and future of residual stress measurement by neutron diffraction

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2007-01-01

    Neutron diffraction method is very much effective for measurements of residual stress and texture. In this paper the present techniques for measurements of residual stress and texture are reviewed and plans of improvement of RESA in JRR-3 and Ibaraki Prefecture's Material Design Diffractometer to be installed in J-PARC are introduced. (author)

  6. Neutron Diffraction Investigation of MnAs under High Pressure

    DEFF Research Database (Denmark)

    Andresen, A.F; Fjellvag, H; Lebech, Bente

    1984-01-01

    Powdered MnAs has been investigated by neutron diffraction in a pressure cryostat, at hydrostatic pressures up to 13 kbar and temperatures down to 4.2 K. It has been found that in the orthorhombic MnP type structure, which under pressure is retained at low temperature, a spiral magnetic structure...

  7. Retained austenite stability investigation in TRIP steel using neutron diffraction

    Czech Academy of Sciences Publication Activity Database

    Zrník, J.; Muránsky, Ondrej; Lukáš, Petr; Nový, Z.; Šittner, Petr; Horňák, P.

    2006-01-01

    Roč. 437, č. 1 (2006), s. 114-119 ISSN 0921-5093 Institutional research plan: CEZ:AV0Z10480505; CEZ:AV0Z10100520 Keywords : TRIP steel * austenite conditioning * neutron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.490, year: 2006

  8. Data Evaluation Procedure for High-resolution Neutron Diffraction Methods

    Czech Academy of Sciences Publication Activity Database

    Strunz, Pavel; Lukáš, Petr; Neov, Dimitar

    2001-01-01

    Roč. 9, - (2001), s. 99-106 ISSN 1023-8166 R&D Projects: GA ČR GV202/97/K038 Institutional research plan: CEZ:AV0Z1048901 Keywords : high-resolution neutron diffraction * profile analysis * modeling Subject RIV: BM - Solid Matter Physics ; Magnetism

  9. Investigation of Methacrylic Acid at High Pressure Using Neutron Diffraction

    DEFF Research Database (Denmark)

    Marshall, William G.; Urquhart, Andrew; Oswald, Iain D. H.

    2015-01-01

    This article shows that pressure can be a low-intensity route to the synthesis of polymethacrylic acid. The exploration of perdeuterated methacrylic acid at high pressure using neutron diffraction reveals that methacrylic acid exhibits two polymorphic phase transformations at relatively low...

  10. Neutron diffraction investigations of internal stress in materials

    International Nuclear Information System (INIS)

    Holden, T.M.

    1994-01-01

    Neutron diffraction measurements of residual stress have been carried out for the past decade in North America and Europe. The particular advantage of neutron diffraction stems from the fact that thermal neutrons are highly penetrating particles, permitting measurements to be made throughout the thickness for example, of 40 mm of steel. Testing has been done on a wide variety of components, ranging from large, 90 cm diameter, steel line pipe welds, through 6 mm thick zirconium alloy pressure tubes, to regions in the neighbourhood of small stationary welds. Where comparisons have been made between finite element calculations of stress and neutron measurements the agreement has been good. In addition to measuring Type 1 stresses, or macro stress fields, much effort has recently been made in measuring phase-interaction stresses in composite materials such as Al:SiC, and intergranular stresses in anisotropic alloys. A number of case studies will be reviewed discussing both macro and micro stresses. Designing a neutron stress experiment requires much discussion between the scientist and the engineer/customer to resolve uncertainties and misconceptions at an early stage, e.g. what is the best reference lattice spacing. The design often requires ancillary measurements to be made of the crystallographic texture which enables the scientist to choose the diffraction lines which best characterize the sample. The approach we have adopted in our laboratory to these problems to satisfy our industrial customers will be outlined. (author). 17 refs, 5 figs

  11. Steel research using neutron beam techniques. In-situ neutron diffraction, small-angle neutron scattering and residual stress analysis

    International Nuclear Information System (INIS)

    Sueyoshi, Hitoshi; Ishikawa, Nobuyuki; Yamada, Katsumi; Sato, Kaoru; Nakagaito, Tatsuya; Matsuda, Hiroshi; Arakaki, Yu; Tomota, Yo

    2014-01-01

    Recently, the neutron beam techniques have been applied for steel researches and industrial applications. In particular, the neutron diffraction is a powerful non-destructive method that can analyze phase transformation and residual stress inside the steel. The small-angle neutron scattering is also an effective method for the quantitative evaluation of microstructures inside the steel. In this study, in-situ neutron diffraction measurements during tensile test and heat treatment were conducted in order to investigate the deformation and transformation behaviors of TRIP steels. The small-angle neutron scattering measurements of TRIP steels were also conducted. Then, the neutron diffraction analysis was conducted on the high strength steel weld joint in order to investigate the effect of the residual stress distribution on the weld cracking. (author)

  12. Neutron powder diffraction under high pressure at J-PARC

    International Nuclear Information System (INIS)

    Utsumi, Wataru; Kagi, Hiroyuki; Komatsu, Kazuki; Arima, Hiroshi; Nagai, Takaya; Okuchi, Takuo; Kamiyama, Takashi; Uwatoko, Yoshiya; Matsubayashi, Kazuyuki; Yagi, Takehiko

    2009-01-01

    It is expected that high-pressure material science and the investigation of the Earth's interior will progress greatly using the high-flux pulse neutrons of J-PARC. In this article, we introduce our plans for in situ neutron powder diffraction experiments under high pressure at J-PARC. The use of three different types of high-pressure devices is planned; a Paris-Edinburgh cell, a new opposed-anvil cell with a nano-polycrystalline diamond, and a cubic anvil high-pressure apparatus. These devices will be brought to the neutron powder diffraction beamlines to conduct a 'day-one' high-pressure experiment. For the next stage of research, we propose construction of a dedicated beamline for high-pressure material science. Its conceptual designs are also introduced here.

  13. Texture analysis of bronze age axes by neutron diffraction

    International Nuclear Information System (INIS)

    Arletti, R.; Giovannini, S.; Cardarelli, A.; Cartechini, L.; Rinaldi, R.; Kockelmann, W.

    2008-01-01

    Neutron diffraction has been utilised as a non-invasive diagnostic tool to gain insight into the ancient metallurgic and manufacturing techniques employed for the production of three bronze age axes from archaic to late bronze age (20th to 13th Century BC). The analysed bronze artefacts are from the ''Terramare'' and other bronze age settlements near Modena, Italy. Neutron diffraction provides the alloy and phase compositions in a totally non destructive approach, without interference from surface alteration and corrosion layers. Furthermore, neutron based texture analysis, with the advantage of large grain statistics deep into the bulk, provides details of the production techniques that can complement traditional metallographic examinations, and may provide unique information for samples that cannot suffer invasive treatments. (orig.)

  14. Texture analysis of bronze age axes by neutron diffraction

    Science.gov (United States)

    Arletti, R.; Cartechini, L.; Rinaldi, R.; Giovannini, S.; Kockelmann, W.; Cardarelli, A.

    2008-01-01

    Neutron diffraction has been utilised as a non-invasive diagnostic tool to gain insight into the ancient metallurgic and manufacturing techniques employed for the production of three bronze age axes from archaic to late bronze age (20th to 13th Century BC). The analysed bronze artefacts are from the “Terramare” and other bronze age settlements near Modena, Italy. Neutron diffraction provides the alloy and phase compositions in a totally non destructive approach, without interference from surface alteration and corrosion layers. Furthermore, neutron based texture analysis, with the advantage of large grain statistics deep into the bulk, provides details of the production techniques that can complement traditional metallographic examinations, and may provide unique information for samples that cannot suffer invasive treatments.

  15. Epi-thermal neutron diffraction of Gd alloy, (3)

    International Nuclear Information System (INIS)

    Watanabe, Noboru; Ishikawa, Yoshikazu; Sekine, Hisashi; Suzuki, Michio; Fujii, Hironobu.

    1975-01-01

    Epi-thermal neutron diffraction of Gd alloy was studied. A single crystal of GdZn was made by the Bridgman's method, and the degree of order was 1.00. One of the epi-thermal neutron diffraction patterns from the GdZn single crystal is shown. The nuclear scattering amplitude of Gd was obtained as bsub(Gd)=(1.15 +- 0.15) x 10 -12 cm, which is in good agreement with the value obtained from the comparison with the magnetic diffraction of Gdsub(0.9)Ysub(0.1). The epi-thermal neutron diffraction of Gdsub(0.85)Thsub(0.15) was also studied. The magnetic satellite line was clearly seen at low temperature. Higher order satellite line could not be observed. The magnetic structures in which the satellite is observed at are proper screw, cycloid, transverse sine wave and conical structures. The possibility of the conical structure was eliminated by the observed diffraction patterns at room temperature and at 80 0 K. The magnetic structure factors for the other three structures were obtained. At present, it is unable to determine the magnetic structure for Gdsub(0.85)Thsub(0.15). (Kato, T.)

  16. Neutron diffraction study of sodium hydrogen selenate Na3H5(SeO4)4. Comparison with the X-ray diffraction data

    International Nuclear Information System (INIS)

    Troyanov, S.I.; Zakharov, M.A.; Reehuis, M.; Kemnitz, E.

    2002-01-01

    The neutron diffraction study of Na 3 H 5 (SeO 4 ) 4 single crystals at 298 and 85 K has confirmed the positions of nonhydrogen atoms obtained in the X-ray diffraction study. Contrary to the X-ray diffraction data, the neutron diffraction data indicate that all the three independent protons are ordered and participate in two asymmetric and one symmetric hydrogen bonds, with the O···O distances being 2.68, 2.61, and 2.48 A. The system of hydrogen bonds is built by complicated chains

  17. Magnetic correlations in oxides: Neutron diffraction and neutron ...

    Indian Academy of Sciences (India)

    dering in nanoparticles, naturally occurring layered materials showing exotic phys- ical properties, interconnect ... Dhruva reactor, Trombay [9,10] and other neutron scattering facilities, located in. Europe. 2. Experimental ... Figure 2 depicts the low-angle Bragg peak intensities as a function of temper- ature. The magnetic ...

  18. Feasibility studies for high pressure neutron powder diffraction experiments

    International Nuclear Information System (INIS)

    Von Dreele, R.B.; Parise, J.

    1990-01-01

    We recently performed two neutron powder diffraction experiments on very small samples on the High Intensity Powder Diffractometer (HIPD). These were done to determine the feasibility of performing in situ high pressure/high temperature neutron diffraction experiments on HIPD at pressures which would exceed the previous limit of ∼50 kbar achievable in a neutron diffraction experiment. The first experiment consisted of examining the product from a high pressure preparation done at Stony Brook. The sample, which had been prepared at 65 kbar and 1000 degree C, consisted of a small platinum capsule filled with CaGeO 3 perovskite. The weights of the capsule included 225 mg of platinum and 49 mg of the germanate. A diffraction experiment taking ∼8.6 hrs at a LANSCE proton beam current of ∼53 μA gave peaks of good intensity from both Pt and CaGeO 3 ; we could begin to see them after only 20 min of beam time. The second experiment was to test the possibility of diffraction from a high pressure apparatus. We placed in the HIPD sample position the central assembly from a 100 kbar octahedral press. Four tungsten carbide anvils and a copper block previously pressed to 65 kbar were held in an aluminum frame. The sample consisted of a small bit of nickel foil (175 mg) placed in a 3 mm hole in the copper block. The active sample volume is defined by the gap between the anvils and the length of the sample. A small portion of the copper block is also seen in this arrangement. This is viewed at 90 degree 2Θ through a similar gap between the anvils by 4 1/2 in. x 12 in. 3 He counter tubes. This arrangement simulates the operating conditions of a high pressure run at 100 kbar and takes advantage of the fixed instrument geometry possible in time-of-flight neutron diffraction experiments

  19. Neutron generator control system

    International Nuclear Information System (INIS)

    Peelman, H.E.; Bridges, J.R.

    1981-01-01

    A method is described of controlling the neutron output of a neutron generator tube used in neutron well logging. The system operates by monitoring the target beam current and comparing a function of this current with a reference voltage level to develop a control signal used in a series regulator to control the replenisher current of the neutron generator tube. (U.K.)

  20. Refractive and diffractive neutron optics with reduced chromatic aberration

    DEFF Research Database (Denmark)

    Poulsen, Stefan Othmar; Poulsen, Henning Friis; Bentley, P.M.

    2014-01-01

    by the use of optics for focusing and imaging. Refractive and diffractive optical elements, e.g. compound refractive lenses and Fresnel zone plates, are attractive due to their low cost, and simple alignment. These optical elements, however, suffer from chromatic aberration, which limit their effectiveness......Thermal neutron beams are an indispensable tool in physics research. The spatial and the temporal resolution attainable in experiments are dependent on the flux and collimation of the neutron beam which remain relatively poor, even for modern neutron sources. These difficulties may be mitigated...... to highly monochromatic beams. This paper presents two novel concepts for focusing and imaging non-monochromatic thermal neutron beams with well-known optical elements: (1) a fast mechanical transfocator based on a compound refractive lens, which actively varies the number of individual lenses in the beam...

  1. Neutron diffraction from the vortex lattice in the heavy-fermion superconductor UPt3

    DEFF Research Database (Denmark)

    Kleiman, R.N.; Broholm, C.; Aeppli, G.

    1992-01-01

    We have used neutron diffraction to observe the vortex lattice of UPt3. This is the first such measurement in a heavy-fermion system, a superconductor below 1 K, or in a system with such a long magnetic penetration depth (6000 +/- 75 angstrom). It also provides the first value for the pair...

  2. Feasibility studies for high pressure neutron powder diffraction experiments

    International Nuclear Information System (INIS)

    Von Dreele, R.B.

    1991-01-01

    We recently performed two neutron powder diffraction experiments on very small samples on the High Intensity Powder Diffractometer (HIPD), to determine the feasibility of performing in situ high pressure/high temperature neutron diffraction experiments on HIPD at pressures which would exceed the previous limit of ∼50kbar achievable in a neutron diffraction experiment. The sample, which had been prepared at 65kbar and 1000degC, consisted of a small platinum capsule filled with CaGeO 3 perovskite. A diffraction experiment taking ∼8.6hrs at a LANSCE proton beam current of ∼53μA gave peaks of good intensity from both Pt and CaGeO 3 ; we could begin to see them after only 20min if beam time. The second experiment was to test the possibility of diffraction from a high pressure apparatus. We placed in the HIPD sample position the central assembly from a 100kbar octahedral press. Four tungsten carbide anvils and a copper block previously pressed to 65kbar were held in an aluminum frame. The sample consisted of a small bit of nickel foil placed in a 3 mm hole in the copper block. The active sample volume is defined by the gap (∼0.7mm) between the anvils and the length of the sample. A small portion of the copper block is also seen in this arrangement. This is viewed at 90deg 2Θ through a similar gap between the anvils by 4 1/2''x12'' 3 He counter tubes. This arrangement simulates the operating conditions of a high pressure run at 100kbar and takes advantage of the fixed instrument geometry possible in time-of-flight neutron diffraction experiments. We obtained a diffraction pattern in ∼7.1hrs and ∼57μA beam current which clearly showed peaks from both copper and nickel with no evidence of diffraction from the anvils or any other part of the assembly. These two experiments clearly demonstrate the feasibility of performing high pressure in situ diffraction experiments in excess of 100kbar on HIPD at LANSCE. (J.P.N.)

  3. Industrial research and development and the role of neutron diffraction

    International Nuclear Information System (INIS)

    Holden, T.M.; Root, J.H.; Tennant, D.C.; Hosbons, R.R.; Holt, R.A.; Mahin, K.W.; Leggett, D.

    1992-01-01

    The property of thermal neutrons that makes them valuable for studying industrial structures is their high penetration through most materials. This means that neutron diffraction can be used as a non-destructive probe for obtaining information about material properties deep inside engineering component. To a large extent we have developed the techniques in response to pressing problems of industry such as the need to measure residual stress fields, the need to understand the grain-to-grain interaction stresses that drive initial growth transients in nuclear reactor materials, and the need to measure temperature and stresses non-invasively in operating engines. (orig.)

  4. Industrial research and development and the role of neutron diffraction

    Science.gov (United States)

    Holden, T. M.; Root, J. H.; Tennant, D. C.; Hosbons, R. R.; Holt, R. A.; Mahin, K. W.; Leggett, D.

    1992-06-01

    The property of thermal neutrons that makes them valuable for studying industrial structures is their high penetration through most materials. This means that neutron diffraction can be used as a non-destructive probe for obtaining information about material properties deep inside engineering components. to a large extent we have developed the techniques in response to pressing problems of industry such as the need to measure residual stress fields, the need to understand the grain-to-grain interaction stresses that drive initial growth transients in nuclear reactor materials, and the need to measure temperature and stresses non-invasively in operating engines.

  5. Investigation of acrylic acid at high pressure using neutron diffraction.

    Science.gov (United States)

    Johnston, Blair F; Marshall, William G; Parsons, Simon; Urquhart, Andrew J; Oswald, Iain D H

    2014-04-10

    This article details the exploration of perdeuterated acrylic acid at high pressure using neutron diffraction. The structural changes that occur in acrylic acid-d4 are followed via diffraction and rationalized using the Pixel method. Acrylic acid undergoes a reconstructive phase transition to a new phase at ∼ 0.8 GPa and remains molecular to 7.2 GPa before polymerizing on decompression to ambient pressure. The resulting product is analyzed via Raman and FT-IR spectroscopy and differential scanning calorimetry and found to possess a different molecular structure compared with polymers produced via traditional routes.

  6. Applications of neutron powder diffraction in materials research

    International Nuclear Information System (INIS)

    Kennedy, S.J.

    1995-01-01

    The aim of this article is to provide an overview of the applications of neutron powder diffraction in materials science. The technique is described with particular attention to comparison with the X-ray powder diffraction technique to which it is complementary. In this context, emphasis is placed on rapid data acquisition and in-situ studies of phase transitions. Examples of some applications of the technique to materials science problems, at the HIFAR research reactor, Lucas Heights are included. 8 refs., 12 figs

  7. Advanced neutron diffraction techniques for strain measurements in polycrystalline materials

    International Nuclear Information System (INIS)

    Mikula, P.; Lukas, P.; Vrana, M.; Klimanek, P.; Kschidock, T.; Macek, K.; Janovec, J.; Osborn, J.C.; Swallowe, G.M.

    1993-01-01

    Three unique high resolution experimental arrangements for nondestructive strain measurements which are based on neutron Bragg diffraction optics with cylindrically bent perfect crystals are reviewed. Using focusing in momentum and real space these techniques yield Δd/d (d-lattice spacing) resolution of 10 -4 - 10 -3 and considerably higher luminosity in comparison with the current dedicated instruments. They permit measurements not only macrostrain components resulting in angular shifts of diffraction peaks but also of microstrains by means of profile-broadening analysis. (orig.)

  8. Neutron Larmor diffraction with double and single precession arm

    Science.gov (United States)

    van Well, A. A.; Rekveldt, M. T.

    2017-06-01

    A review is given of double and single arm Larmor diffraction. With the former a lattice-spacing resolution down to 10-6 can be obtained. The latter is a good high-resolution alternative if the sample or sample environment disturbs the magnetic field, e.g. ferromagnetic samples or applied magnetic fields. By choosing the tilt angle of the precession fields the optimum resolution can be set at a scattering angle at choice. The resolution for both single-crystal and polycrystalline samples is discussed in depth and is compared with conventional neutron-diffraction techniques.

  9. Texture evaluation in ductile fracture process by neutron diffraction measurement

    Science.gov (United States)

    Sunaga, H.; Takamura, M.; Ikeda, Y.; Otake, Y.; Hama, T.; Kumagai, M.; Suzuki, H.; Suzuki, S.

    2016-08-01

    A neutron diffraction measurement was performed to reveal microstructural aspects of the ductile fracture in ferritic steel. The diffraction patterns were continuously measured at the center of the reduced area while a tensile specimen was loaded under tension until the end of the fracture process. The measurement results showed that the volume fraction of (110)-oriented grains increased when the texture evolved as a result of plastic deformation. But the mechanism of texture evolution may be changed during necking, decreasing an increase rate of the volume fraction.

  10. Neutron diffraction study of the structure of liquid water

    International Nuclear Information System (INIS)

    Ohtomo, Norio; Arakawa, Kiyoshi.

    1978-01-01

    The structure factor for heavy water at 17 0 C up to the Q value of 18 A -1 has been determined by means of the time-of-flight (TOF) diffraction method using pulsed neutrons produced by LINAC. The result has been compared with structure factors calculated on the basis of the various structure models of liquid water; the ''uncorrelated orientation model'' and the ''watery model'' (Page and Powles), the ''near-neighbor model'' (Narten) and the ''revised watery model'' (authors). None of these models has been found to fit the neutron diffraction data satisfactorily over the entire range of Q, though our curve is somewhat improved in comparison with the curves for earlier models. Some discussions about the various structure models of liquid water have been made. (auth.)

  11. Structural study of oxide superconductors by neutron diffraction

    International Nuclear Information System (INIS)

    Asano, H.

    1991-01-01

    A nonstoichiometric structure of Nd 1+x Ba 2-x Cu 3 O 7-z has been refined by Rietveld analysis of neutron powder diffraction data. A Ba site is substituted partially by Nd atoms, which causes a decrease of hole carriers on a CuO 2 plane and lowers T c . T c recovers again with increasing content of oxygen introduced by high-pressure oxygen annealing. A modulated structure in Bi 2 (Sr, Ca) 3 Cu 2 O 8+z has been clarified by simultaneous Rietveld refinement of neutron and X-ray powder diffraction data. It is shown that the modulated structure is resulted from excess oxygen atoms incorporated in a Bi-O layer. (author). 6 refs.; 7 figs.; 1 tab

  12. Neutron diffraction studies of laser welding residual stresses

    Science.gov (United States)

    Petrov, Peter I.; Bokuchava, Gizo D.; Papushkin, Igor V.; Genchev, Gancho; Doynov, Nikolay; Michailov, Vesselin G.; Ormanova, Maria A.

    2016-01-01

    The residual stress and microstrain distribution induced by laser beam welding of the low-alloyed C45 steel plate was investigated using high-resolution time-of-flight (TOF) neutron diffraction. The neutron diffraction experiments were performed on FSD diffractometer at the IBR-2 pulsed reactor in FLNP JINR (Dubna, Russia). The experiments have shown that the residual stress distribution across weld seam exhibit typical alternating sign character as it was observed in our previous studies. The residual stress level is varying in the range from -60 MPa to 450 MPa. At the same time, the microstrain level exhibits sharp maxima at weld seam position with maximal level of 4.8·10-3. The obtained experimental results are in good agreement with FEM calculations according to the STAAZ model. The provided numerical model validated with measured data enables to study the influence of different conditions and process parameters on the development of residual welding stresses.

  13. Neutron diffraction by monocrystals of inorganic and elementary organic compounds

    International Nuclear Information System (INIS)

    Becker, G.; Hauser, H.D.

    1992-01-01

    The phase of preparation and X-ray structural analysis of the compounds has been completed following the synthetical preparation of compounds sensitive to oxidation and pyrolysis, in this case: phosphonic acid, potassium silanide, lithium dihydrogenphosphide * DME, bis[lithium-tri(tert.butyl)alanate], dibromophenylbismuthate, potassium tetrahydride aluminate, and phosphinic acid. The work was started is neutron diffraction experiments for detecting the positions of the hydrogen and carbon atoms, in order to analyse space group problems. (BBR) [de

  14. Preferred orientations in niobium determined by neutron diffraction

    International Nuclear Information System (INIS)

    Veno, S.J.M.; Fotedar, J.L.; Oles, A.; Parente, C.B.R.

    1977-01-01

    Neutron diffraction has been utilized to study textures developed in polycrystalline niobium, cold rolled to 60% nd 80% in thickness. The pole figures obtained were analysed in terms of the following ideal orientations (112)/110/, (001)/110/, (113)/110/, (111)/112/, (111)/110/. A comparison of these, with textures in b.c.c metals shows a close similarity [pt

  15. Advanced neutron diffraction techniques for strain measurements in polycrystalline materials

    OpenAIRE

    Mikula , P.; LukÁs , P.; VrÁna , M.; Klimanek , P.; Kschidock , T.; Macek , K.; Janovec , J.; Osborn , J.; Swallowe , G.

    1993-01-01

    Three unique high resolution experimental arrangements for nondestructive strain measurements which are based on neutron Bragg diffraction optics with cylindrically bent perfect crystals are reviewed. Using focusing in momentum and real space these techniques yield Δd/d (d-lattice spacing) resolution of 10-4 - 10-3 and considerably higher luminosity in comparison with the current dedicated instruments. They permit measurements not only macrostrain components resulting in angular shifts of dif...

  16. Study of FeC12 by neutron diffraction

    International Nuclear Information System (INIS)

    Herpin, A.; Meriel, P.

    1959-01-01

    Magnetic measurements have shown that anhydrous ferrous chloride behaves as a metamagnetic at temperatures below 24 deg. K, in other words as an antiferromagnetic sensitive to the action of an external field of moderate strength. The aim of the neutron diffraction study is to determine precisely the arrangement of the magnetic moments, and to follow its evolution as a function of the applied field. (author) [fr

  17. Practical conditions in the neutron diffraction under high pressure

    International Nuclear Information System (INIS)

    Kamigaki, Kazuo; Ohashi, Masayoshi

    1993-01-01

    Practical analysis is made on some conditions in utilizing neutrons for the study of atomistic structure of materials under high pressure. Investigation is made on the geometrical conditions; size of the specimen, width of slits, and the rate of extra-scattering. Experiments are performed on the effects of absorption by high pressure cell and the disturbance due to an overlapping of diffraction peaks. An observation is presented on the pressure-induced transformation in RbBr. (author)

  18. The microscopic structure of liquid mercury from neutron and x-ray diffraction

    International Nuclear Information System (INIS)

    Bafile, U.

    1999-01-01

    Complete text of publication follows. New neutron and X-ray diffraction investigations of the microscopic structure of liquid mercury were recently carried out. The direct comparison of the structure factors S(Q) measured with the two techniques showing a very good agreement, is reported here. It is also shown that, by exploiting the very good stability of the D20 neutron diffractometer at ILL, Grenoble, the very small density effects due to pressurization of mercury up to 2 kbar can be detected to obtain the first neutron measurement of the isothermal density derivative of S(Q), which is a very sensitive probe of the interaction law in liquid systems. (author)

  19. European standardization activities on residual stress analysis by neutron diffraction

    International Nuclear Information System (INIS)

    Youtsos, A.G.; Ohms, C.

    2002-01-01

    A main objective of a recently completed European research project, RESTAND - residual stress standard using neutron diffraction, was to develop industrial confidence in the application of the neutron-diffraction technique for residual stress measurement and its principal deliverable was a relevant draft code of practice. In fact this draft standard was jointly developed within RESTAND and VAMAS TWA 20 - an international pre-normative research activity. As no such standard is yet available, on the basis of this draft standard document the European Standards Committee on Non-Destructive Testing (CEN TC/138) has established a new ad hoc Work Group (AHG7). The objective of this group is the development of a European pre-standard on a 'test method for measurement of residual stress by neutron diffraction'. The document contains the proposed protocol for making the measurements. It includes the scope of the method, an outline of the technique, the calibration and measurement procedures recommended, and details of how the strain data should be analysed to calculate stresses and establish the reliability of the results obtained. (orig.)

  20. European standardization activities on residual stress analysis by neutron diffraction

    Science.gov (United States)

    Youtsos, A. G.; Ohms, C.

    A main objective of a recently completed European research project, RESTAND - residual stress standard using neutron diffraction, was to develop industrial confidence in the application of the neutron-diffraction technique for residual stress measurement and its principal deliverable was a relevant draft code of practice. In fact this draft standard was jointly developed within RESTAND and VAMAS TWA 20 - an international pre-normative research activity. As no such standard is yet available, on the basis of this draft standard document the European Standards Committee on Non-Destructive Testing (CEN TC/138) has established a new ad hoc Work Group (AHG7). The objective of this group is the development of a European pre-standard on a `test method for measurement of residual stress by neutron diffraction'. The document contains the proposed protocol for making the measurements. It includes the scope of the method, an outline of the technique, the calibration and measurement procedures recommended, and details of how the strain data should be analysed to calculate stresses and establish the reliability of the results obtained.

  1. Maximum Entropy Method for neutron powder diffraction data

    International Nuclear Information System (INIS)

    Sakata, Makoto; Uno, Tatsuya; Takata, Masaki; Takagi, Masahiro; Kumazawa, Shintaro; Howard, C.J.

    1993-01-01

    The Maximum Entropy Method (MEM) is powerful method to restore the accurate electron density distribution from X-ray diffraction data. It deals with electron density which is always positive. In order to analyze neutron diffraction data by the MEM, it is necessary to overcome the difficulty of negative scattering length of some atoms, such as Ti, Mn. In this work, a new approach to solving the negative scattering problem is described. It is based on nuclear densities rather than densities of scattering length, because the nuclear densities are always positive. The new method is successfully applied to analyze the neutron powder data from two polymorphs of TiO 2 , i.e. rutile and anatase. The procedure, like its X-ray counter-part, requires no structural model. The nuclear densities of rutile obtained by the present method is compared with the electron density distribution previously obtained by the MEM analysis. In contrast to the electron density distribution, nuclear densities show completely no density between Ti and O nuclei. It is also revealed that both Ti and O nuclear densities are confined within a very limited space. The present analysis provide a good demonstration of complementary nature of neutron and X-ray diffraction. (author)

  2. Residual stress measurements by means of neutron diffraction

    International Nuclear Information System (INIS)

    Pintschovius, L.; Jung, V.; Macherauch, E.; Voehringer, O.

    1983-01-01

    A new method for the analysis of multiaxial residual stress states is presented, which is based on high resolution neutron diffraction. It is analogous to X-ray stress analysis, but the use of neutrons instead of X-rays allows the analysis of the stress distributions also in the interior of technical components in a non-destructive way. To prove the feasibility of the method, investigations of the loading stress distributions of an aluminium bar subjected to purely elastic bending were performed. Limiting factors due to the volume of the internal probe region and the sample thickness are discussed. Complete neutron residual stress analyses were carried out for a plastically deformed bending bar and a transformation-free water-quenched steel cylinder. The results are in fairly good agreement with theoretical expectations and with X-ray control measurements at the surface of the objects. (Auth.)

  3. Diffraction plane dependence of elastic constants in ferritic steel in neutron diffraction stress measurement

    International Nuclear Information System (INIS)

    Hayashi, Makoto; Ishiwata, Masayuki; Minakawa, Noriaki; Funahashi, Satoru; Root, J.H.

    1995-01-01

    Neutron diffraction measurement have been made to investigate the diffraction plane dependence of elastic constants in ferritic steel. The measured diffraction planes were 110, 220, 112, 222 and 200. In the measurement a small tensile specimen was loaded in the tensile test rig specially designed for a neutron diffractometer. The strains obtained for five diffraction planes increased almost in proportion to the applied stress up to 230 MPa nearly equivalent to the yield stress. The mean elastic constants obtained were E=243 GPa and ν=0.28 for 110, 220 and 112, 182 GPa and 0.31 for softest 200, and 268 GPa and 0.30 for stiffest 222, respectively. The bulk elastic constants, E=222 GPa and ν=0.29, measured by the strain gauges almost agreed with the mean values for 110, 220 and 112. The Kroner elastic model is found to account for the diffraction plane dependence of Young's modulus and Poisson's ratio of the ferritic steel. (author)

  4. Properties of planetary ices in the NH3 + CO2 ± H2O ternary system using neutron diffraction and ab initio calculations

    Science.gov (United States)

    Howard, C. M.; Wood, I. G.; Fortes, A. D.; Vocadlo, L.

    2016-12-01

    BackgroundInteractions between simple molecules are of fundamental interest across diverse areas of the physical sciences, and the ternary system NH3 + CO2 ± H2O is no exception. In the outer solar system, interaction of CO2 with aqueous ammonia is likely to occur, synthesizing `rock-forming' minerals [1], with CO2 perhaps playing a role in ammonia-water oceans and cryomagmas inside icy planetary bodies - the discovery of ammonium carbonates in a crater of Pluto's moon Charon [2] adds weight to CO2 occuring in these planetary environments. In the same context, ammonium carbonates may have some astrobiological relevance, since removal of water leads to the formation of urea. On Earth, combination of CO2 with aqueous ammonia has relevance to carbon capture schemes [3], and there is interest in using such materials for hydrogen storage in fuel cells [4]. Consequently, from earthly matters of climate change to the study of extraterrestrial ices, understanding the structures and properties of ammonium carbonates are important. Despite this, our knowledge of ammonium carbonates is limited under ambient conditions of pressure and temperature and is entirely absent at the higher pressures, severely limiting our ability to model the behaviour of NH3 + CO2 ± H2O solids and fluids in planetary environments. ResultsWe report the results of several experiments using variable pressure and temperature neutron diffraction work on ammonium carbonate monohydrate, ammonium bicarbonate and ammonium carbamate, with complementary Density Functional Theory (DFT) calculations. The excellent agreement between experiments and DFT calculations obtained so far adds weight to the accuracy of calculated material properties of ammonium sesquicarbonate monohydrate and several polymorphs of urea where little empirical data exists. These experimental and computational studies provide the structural, thermoelastic and vibrational information required for accurate planetary modelling and remote

  5. Engineering related neutron diffraction measurements probing strains, texture and microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Clausen, Bjorn [Los Alamos National Laboratory; Brown, Donald W [Los Alamos National Laboratory; Tome, Carlos N [Los Alamos National Laboratory; Balogh, Levente [Los Alamos National Laboratory; Vogel, Sven C [Los Alamos National Laboratory

    2010-01-01

    Neutron diffraction has been used for engineering applications for nearly three decades. The basis of the technique is powder diffraction following Bragg's Law. From the measured diffraction patterns information about internal, or residual, strain can be deduced from the peak positions, texture information can be extracted from the peak intensities, and finally the peak widths can provide information about the microstructure, e.g. dislocation densities and grain sizes. The strains are measured directly from changes in lattice parameters, however, in many cases it is non-trivial to determine macroscopic values of stress or strain from the measured data. The effects of intergranular strains must be considered, and combining the neutron diffraction measurements with polycrystal deformation modeling has proven invaluable in determining the overall stress and strain values of interest in designing and dimensioning engineering components. Furthelmore, the combined use of measurements and modeling has provided a tool for elucidating basic material properties, such as critical resolved shear stresses for the active deformation modes and their evolution as a function of applied deformation.

  6. 3DXRD microscopy - a comparison with neutron diffraction

    CERN Document Server

    Poulsen, H F

    2002-01-01

    3DXRD microscopy is a novel tool for fast and non-destructive characterisation of the individual grains and sub-grains inside bulk materials (powders or polycrystals). The method is based on diffraction with hard X-rays (E>50 keV), enabling 3D studies of millimeter to centimeter-thick specimens. The position, volume, orientation, and elastic strain can be determined in hundreds of grains simultaneously. Furthermore, the evolution of the plastic strain can be characterised from grain rotations. Likewise, for coarse-grained materials, the topography of the grain boundaries can be mapped. The status of the technique is presented and the potential for in situ processing studies illustrated. The hard-X-ray method is compared to conventional neutron-diffraction techniques: texture and strain measurements, small-angle scattering, and in situ powder diffraction. (orig.)

  7. Ellipsometric and neutron diffraction study of pentane physisorbed on graphite.

    Science.gov (United States)

    Kruchten, Frank; Knorr, Klaus; Volkmann, Ulrich G; Taub, Haskell; Hansen, Flemming Y; Matthies, Blake; Herwig, Kenneth W

    2005-08-02

    High-resolution ellipsometry and neutron diffraction measurements have been used to investigate the structure, growth, and wetting behavior of fluid pentane (n-C(5)H(12)) films adsorbed on graphite substrates. We present isotherms of the thickness of pentane films adsorbed on the basal-plane surfaces of a pyrolytic graphite substrate as a function of the vapor pressure. These isotherms are measured ellipsometrically for temperatures between 130 and 190 K. We also describe neutron diffraction measurements in the temperature range 11-140 K on a deuterated pentane (n-C(5)D(12)) monolayer adsorbed on an exfoliated graphite substrate. Below a temperature of 99 K, the diffraction patterns are consistent with a rectangular centered structure. Above the pentane triple point at 143.5 K, the ellipsometric measurements indicate layer-by-layer adsorption of at least seven fluid pentane layers, each having the same optical thickness. Analysis of the neutron diffraction pattern of a pentane monolayer at a temperature of 130 K is consistent with small clusters having a rectangular-centered structure and an area per molecule of approximately 37 A(2) in coexistence with a fluid monolayer phase. Assuming values of the polarizability tensor from the literature and that the monolayer fluid has the same areal density as that inferred for the coexisting clusters, we calculate an optical thickness of the fluid pentane layers in reasonable agreement with that measured by ellipsometry. We discuss how these results support the previously proposed "footprint reduction" mechanism of alkane monolayer melting. In the hypercritical regime, we show that the layering behavior is consistent with the two-dimensional Ising model and determine the critical temperatures for layers n = 2-5.

  8. Sensitivity of the neutron crystal diffraction experiment to the neutron EDM and to the nuclear P-,T-violating forces

    OpenAIRE

    Baryshevsky, V. G.; Cherkas, S. L.

    2013-01-01

    We establish a link between an angle of the neutron polarization rotation in a crystal diffraction experiment and constants of the P-,T- violating interactions. The consideration applies to the energy range of thermal and resonance neutrons.

  9. Industrial applications of neutron beam and outline of J-PARC (1). Industrial application technologies of neutron diffraction

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2008-01-01

    Neutron diffraction method is used to be applied to measure micro-structure for material physics and chemicals. Recently neutron diffraction has been used for non-destructive testing, such as radiography, prompt gamma analysis and residual stress. In the industrial applications residual stresses and textures in the engineering materials are measured using neutron diffraction. In this paper the present techniques for measurements of residual stress and texture are mainly reviewed. (author)

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

    International Nuclear Information System (INIS)

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

    1989-11-01

    Uranium silicides have been considered for use as reactor fuels in both high power and low enrichment applications. However, U 3 Si was found to become amorphous under irradiation and to become mechanically unstable to rapid growth by plastic flow. U 2 Si 2 appears to be stable against amorphization at low displacement rates, but the extent of this stability is uncertain. Although the mechanisms responsible for plastic flow in U 3 Si and other amorphous systems are unknown, as is the importance of crystal structure for amorphization, it may not be surprising that these materials amorphize, in light of the fact that many radioactive nuclide - containing minerals are known to metaminctize (lose crystallinity) under irradiation. The present experiment follows the detailed changes in the crystal structures of U 3 Si and U 3 Si 2 introduced by neutron bombardment and subsequent uranium fission at room temperature. U-Si seems the ideal system for a neutron diffraction investigation since the crystallographic and amorphous forms can be studied simultaneously by combining conventional Rietveld refinement of the crystallographic phases with Fourier-filtering of the non-crystalline scattering component

  11. Neutron Diffraction Studies of Intercritically Austempered Ductile Irons

    Energy Technology Data Exchange (ETDEWEB)

    Druschitz, Alan [University of Alabama, Birmingham; Aristizabal, Ricardo [University of Alabama, Birmingham; Druschitz, Edward [University of Alabama, Birmingham; Hubbard, Camden R [ORNL; Watkins, Thomas R [ORNL

    2011-01-01

    Neutron diffraction is a powerful tool that can be used to identify the phases present and to measure the spacing of the atomic planes in a material. Thus, the residual stresses can be determined within a component and/or the phases present. New intercritically austempered irons rely on the unique properties of the austenite phase present in their microstructures. If these materials are to see widespread use, methods to verify the quality (behavior consistency) of these materials and to provide guidance for further optimization will be needed. Neutron diffraction studies were performed at the second generation neutron residual stress facility (NRSF2) at the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory on a variety of intercritically austempered irons. For similar materials, such as TRIP steels, the strengthening mechanism involves the transformation of metastable austenite to martensite during deformation. For the intercritically austempered ductile irons two different deformation/strengthening mechanisms, phase transformation and slip, dependent upon the iron chemistry, were observed. Lattice strain and phase fraction data as a function of applied stress are presented.

  12. Neutron diffraction measurements of residual stress for industrial application

    International Nuclear Information System (INIS)

    Minakawa, Nobuaki

    1999-01-01

    The neutron diffraction method is used to measure the inner strain distribution of material using the penetrating power of neutron as one of the effective use of the research reactor for the study and to evaluate a correct fatigue and a lifetime. Internal residual stress measurements have attracted great interest in material science where it is especially important to know the distribution of the internal stress when we estimated the strength of construction materials or processed goods for the industrial applications. This measurement can be applied to the study of hardening of processed goods, metal fatigue, strain of welding. Conventional techniques to measure strain such as strain gauge method, optical interference fringes method, X-ray diffraction method, Raman spectroscopic analysis method, and magnetostriction method, etc. can measure the strain only near the surface of materials. On the other hand, neutron diffractometer for residual stress analysis, RESA, installed at T2-1 port of JRR-3M enables us to study the internal stress non-destructively. (J.P.N.)

  13. Single crystal neutron diffraction studies on ferroelectric materials. A review on neutron diffraction works made using the 4-circle diffractometer at KUR

    International Nuclear Information System (INIS)

    Iwata, Yutaka; Mitani, Shigeshi; Shibuya, Iwao

    1994-01-01

    Summary is made on the single crystal neutron diffraction works carried out over the past 30 years using 4-circle neutron diffractometer installed at B-3 beam hole of the Kyoto University Reactor. Subjects dealt with are studies on structure determinations and investigations on phase transition mechanism in various ferroelectric materials and related substances. New applications are also introduced on neutron diffraction method for investigating molecular dynamics and behavior of hydrogens in crystals. (author) 83 refs

  14. Neutron diffraction technique as a method for material studies

    International Nuclear Information System (INIS)

    Belhorma, B.; Labrim, H.; Gandou, Z.

    2010-01-01

    The Morocco's first Nuclear Research has been constructed in CNESTEN. The reactor divergence has been tested, and the nominal power of 2MW was successfully achieved. The reactor has 4 beam ports two of them are projected for neutron scattering. Such technique allows studying the crystallographic and magnetic structures of materials using the thermal neutrons produced in the reactor. the powder diffractometer has been designed. Component reception and installation procedures are in progress. The second experiment consists on small angle neutron scattering that allows the study of soft matter and polymers in the range of 1-50 nm. The third technique that can complete the two previous is the 4-circle neutron spectrometry which is designed mainly to study structural properties of the mono-crystalline material and texture.This technique is complementary to the X-ray diffraction already available in CNESTEN. Some applications of this technique are: --to determine the crystallographic and magnetic structure of polycrystalline materials.-- to study the texture in metals and alloys.-- to perform holography measurement

  15. Residual stress investigations by neutron diffraction at JRC-Petten

    Science.gov (United States)

    Youtsos, A. G.; Ohms, C.; Timke, Th.

    1997-02-01

    Reliable estimates of residual stresses based on non-destructive testing techniques have recently become an essential requirement for the efficient design of advanced materials. Over the last ten years the neutron scattering technique has been recognized as a powerful tool in the characterization of such materials. In this paper we briefly describe the neutron diffraction facilities at the high flux reactor (HFR) at Petten. Experimental data on two specimens are next presented. For the first specimen, an austenitic steel ring exhibiting sharp residual stress gradients, our findings, are compared against similar data obtained elsewhere. For the second specimen, a metal/ceramic composite, the test data, are compared against numerical results derived by numerical modelling of the composite's manufacturing process.

  16. Dislocation Characteristics in Lath Martensitic Steel by Neutron Diffraction

    Science.gov (United States)

    Harjo, S.; Kawasaki, T.; Gong, W.; Aizawa, K.

    2016-09-01

    In situ neutron diffraction during tensile deformation of an as-quenched lath martensitic 22SiMn2TiB steel, was performed using a high resolution and high intensity time- of-flight neutron diffractometer. The characterizations of dislocations were analyzed using the classical Williamson-Hall (cWH) and modified Williamson-Hall (mWH) plots on the breadth method, and the convolutional multiple whole profile (CMWP) fitting method. As results, the dislocation density as high as 1015 m-2 in the as-quenched martensitic steel was determined. The dislocation density was found to decrease qualitatively with plastic deformation by the cWH and mWH plots, but hardly to change by the CMWP method. The scanning transmission electron microscopy observation supported the results of the latter method. In the CMWP method, the parameter M that represents the arrangement of dislocations was found to decrease rapidly where a very high work hardening was observed.

  17. A neutron diffraction study of purple membranes under pressure.

    Science.gov (United States)

    Rossand, Isabelle Gundel; Zaccai, Giuseppe; Fragneto, Giovanna

    2010-11-01

    Neutron diffraction from hydrated stacks of natural two-dimensional crystal patches of purple membrane from Halobacterium salinarum was studied as a function of pressure. Measurements in H(2)O and D(2)O permitted the determination of the distribution of water of hydration in the in-plane projection of the membrane. The main experimental difference observed between the samples at 300 MPa and atmospheric pressure was a major reorganization of the hydration around the lipid head groups and protein, associated with a protein conformational change and small reductions in lamellar (stacking) and in-plane lattice spacings, which was consistent with the compressibility of membrane-protein and lipid components.

  18. Neutron diffraction studies for the measurement of strains and stresses

    International Nuclear Information System (INIS)

    Swallowe, G.M.; Wimpory, R.C.

    1999-01-01

    This paper describes the neutron diffraction method for the measurements of residual strains and illustrated the method with examples of measurements on a mining chain link and a Single Lap Shear (SLS) Joint. It is shown that compressive stresses in the chain surface contribution to the fatigue resistance of the link.. Results for the SLS joint cast doubt on current finite elements models of joint stress distribution and quantity the stress redistribution which occurs in the joint with ageing. The extension of the method for the measurement of dislocation densities and dislocation cell sizes is illustrated with an example of a plastically deformed cooper sample.(author)

  19. Thermal expansion study of simulated DUPIC fuel using neutron diffraction

    International Nuclear Information System (INIS)

    Kang, Kweon Ho; Ryu, H. J.; Bae, J. H.; Kim, H. S.; Song, K. C.; Yang, M. S.; Choi, Y. N.; Han, Y. S.; Oh, H. S.

    2001-07-01

    The lattice parameters of simulated DUPIC fuel and UO2 were measured from room temperature to 1273 K using neutron diffraction to investigate the thermal expansion and density variation with temperature. The lattice parameter of simulated DUPIC fuel is lower than that of UO2 and the linear thermal expansion of simulated DUPIC fuel is higher than that of UO2. For the temperature range from 298 to 1273 K, the average linear thermal expansion coefficients for UO2 and simulated DUPIC fuel are 10.471 ''10-6 and 10.751 ''10-6 K-1, respectively

  20. Investigation of Methacrylic Acid at High Pressure Using Neutron Diffraction.

    Science.gov (United States)

    Marshall, William G; Urquhart, Andrew J; Oswald, Iain D H

    2015-09-10

    This article shows that pressure can be a low-intensity route to the synthesis of polymethacrylic acid. The exploration of perdeuterated methacrylic acid at high pressure using neutron diffraction reveals that methacrylic acid exhibits two polymorphic phase transformations at relatively low pressures. The first is observed at 0.39 GPa, where both phases were observed simultaneously and confirm our previous observations. This transition is followed by a second transition at 1.2 GPa to a new polymorph that is characterized for the first time. On increasing pressure, the diffraction pattern of phase III deteriorates significantly. On decompression phase III persists to 0.54 GPa before transformation to the ambient pressure phase. There is significant loss of signal after decompression, signifying that there has been a loss of material through polymerization. The orientation of the molecules in phase III provides insight into the possible polymerization reaction.

  1. Neutron diffraction investigation of lattice microstrain in ferrite steel

    International Nuclear Information System (INIS)

    Camanzi, A.; Moze, O.

    1992-01-01

    The degradation of carbon steels when exposed to H rich environments is well known to result in catastrophic failure. In order to characterize in a comprehensive manner the structural effects of hydrogenation, a series of high resolution neutron powder diffraction measurements were carried out on cross-sections of carbon steel segments used for gas pipelines. Peak positions were measured to an accuracy of 0.001%, whilst line broadening of individual peaks was measured to an accuracy of 0.1%. The (h k l) dependent peak linewidths were fitted using a pseudo-Voigt peak shape function. Non-hydrogenated materials were found to display a different diffraction linewidth dependence on the crystal elastic anisotropy than hydrogenated materials. (orig.)

  2. Precise structural analysis of methane hydrate by neutron diffraction

    International Nuclear Information System (INIS)

    Igawa, Naoki; Hoshikawa, Akinori; Ishii, Yoshinobu

    2006-01-01

    Methane hydrate has attracted great interest as an energy resource to replace natural gas since this material is deposited in the seafloor and the deposits are estimated to exceed those of natural gas. Understanding the physical proprieties, such as the temperature dependence of the crystal structure, helps to specify the optimum environmental temperature and pressure during drilling, transport, and storage of methane hydrate. Clathrate hydrates consisted of encaging atomic and/or molecular species as a guest and host water formed by a hydrogen bonding. Although many studies on the clathrate hydrate including methane hydrate were reported, no detailed crystallographic property has yet been cleared. We focused on the motion of methane in the clathrate hydrate by the neutron diffraction. The crystal structure of the methane hydrate was analyzed by the applying the combination of the Rietveld refinement and the maximum entropy method (MEM) to neutron powder diffraction. Temperature dependence of the scattering-length density distribution maps revealed that the motion of methane molecules differs between the shapes of dodecahedron and tetrakaidecahedron. (author)

  3. Magnetostructural transition in Fe5SiB2 observed with neutron diffraction

    Czech Academy of Sciences Publication Activity Database

    Cedervall, J.; Kontos, S.; Hansen, T. C.; Balmes, O.; Martinez-Casado, F. J.; Matěj, Z.; Beran, Přemysl; Svedlindh, P.; Gunnarsson, K.; Sahlberg, M.

    2016-01-01

    Roč. 235, MAR (2016), s. 113-118 ISSN 0022-4596 Institutional support: RVO:61389005 Keywords : magnetism * X-ray diffraction * neutron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.299, year: 2016

  4. A cubic-anvil high-pressure device for pulsed neutron powder diffraction.

    Science.gov (United States)

    Abe, J; Arakawa, M; Hattori, T; Arima, H; Kagi, H; Komatsu, K; Sano-Furukawa, A; Uwatoko, Y; Matsubayashi, K; Harjo, S; Moriai, A; Ito, T; Aizawa, K; Arai, M; Utsumi, W

    2010-04-01

    A compact cubic-anvil high-pressure device was developed for in situ neutron powder diffraction studies. In this device, a cubic shaped pressure medium is compressed by six anvils, and neutron beams pass through gaps between the anvils. The first high-pressure experiment using this device was conducted at J-PARC and clearly showed the neutron diffraction patterns of Pb. Combining the cubic-anvil high-pressure device with a pulsed neutron source will prove to be a useful tool for neutron diffraction experiments.

  5. Refinement procedures of hydrogen and hydration structures of proteins by neutron diffraction technique

    International Nuclear Information System (INIS)

    Chatake, Toshiyuki; Morimoto, Yukio

    2007-01-01

    Neutrons have a unique role to play in determining the structure and dynamics of proteins and their complexes. Water molecules surrounding a protein play important roles in maintaining its structural stability. However, the hydration structures of most proteins are not known well at an atomic level because x-ray protein crystallography has difficulties to localize the position of hydrogen atoms, while neutron crystallography has not problem in determining the position of hydrogen atoms with high accuracy. A software suite, called Crystallography and NMR System (CNS), has been developed for macromolecular structure determinations by x-ray crystallography or solution nuclear magnetic resonance spectroscopy by A.T. Brunger et al. The software CNS is highly flexible, and is applied for neutron diffraction measurements after some modifications of parameters used in the software. The fundamental modifications are the followings; D atoms in replace of H atoms, and the substitution of neutron scattering lengths for x-ray scattering factors. Moreover, in neutron diffraction data analysis, an important problem rests on the introduction of hydrogen atoms into the software of x-ray crystallography without hydrogen atoms. After the above procedures, the software modified is applied to determine the molecular structure of histidine residue associated with hydrogen atoms. (author)

  6. Neutron diffraction on CeMnAlD{sub x} (0{<=}x{<=}2.5)

    Energy Technology Data Exchange (ETDEWEB)

    Spatz, P.; Gross, K.; Schlapbach, L. [Fribourg Univ. (Switzerland); Fischer, P.; Fauth, F. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    CeMnAl was found to absorb considerable amounts of hydrogen. Part of the totally stored hydrogen is absorbed at low pressures (< 10 mbar). Additional hydrogen can be absorbed and desorbed reversible in a wide pressure range (10 mbar to 10 bar) at room temperature. In order to a better understanding of this new metal-hydride system, we performed neutron diffraction on deuterated CeMnAl samples with different D-concentrations. (author) 1 fig., 2 refs.

  7. In situ neutron diffraction under high pressure—Providing an insight into working catalysts

    OpenAIRE

    Kandemir, T.; Wallacher, D.; Hansen, T.; Liss, K.; Naumann d'Alnoncourt, R.; Schlögl, R.; Behrens, M.

    2012-01-01

    In the present work the construction and application of a continuous flow cell is presented, from which neutron diffraction data could be obtained during catalytic reactions at high pressure. By coupling an online gas detection system, parallel structure and activity investigations of working catalysts under industrial relevant conditions are possible. The flow cell can be operated with different feed gases in a wide range from room temperature to 603 K. Pressures from ambient up to 6 MPa are...

  8. Some Novel Bragg Diffraction Optics Elements for Neutron Scattering at Steady State Neutrons Sources

    Czech Academy of Sciences Publication Activity Database

    Mikula, Pavol; Lukáš, Petr; Šaroun, Jan; Vrána, Miroslav; Wagner, V.

    2001-01-01

    Roč. 70, - (2001), s. 477-479 ISSN 0031-9015. [Proceedings of the 1st International Symposium on Advanced Science Research (ASR-2000). Tokai, 31.10.2000-02.11.2000] R&D Projects: GA ČR GV202/97/K038; GA AV ČR IAA1048003 Keywords : bragg diffraction * neutron optics * bent crystals Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.628, year: 2001

  9. On the neutron diffraction in crystals in the field of a standing sound wave

    International Nuclear Information System (INIS)

    Grigoryan, K.K.; Hayrapetyan, A.G.; Petrosyan, R.G.

    2010-01-01

    The diffraction of neutrons is considered in crystals under the influence of a standing sound wave. The scattering probability is calculated for the elastic neutron-crystal interaction, whereas the neutron-standing sound wave interaction can be either elastic and inelastic. The possibility of short-wave (high-energy) neutrons diffraction is illustrated. It is shown that the Debye-Waller factor can be changed and tuned. The analysis of conservation laws are adduced both for thermal and short-wave neutrons. The formation of a 'sublattice' is shown in the process of neutrons elastic diffraction with respect to standing sound wave. The analogous to the Kapitza-Dirac effect is considered for neutrons. The problem is solved within the frame of non-stationary S-matrix theory, where the neutron-phonon interaction is described by the Fermi pseudopotential, which is considered as a perturbation.

  10. Neutron diffraction study of TiCxNyHz

    International Nuclear Information System (INIS)

    Khidirov, I.

    1996-01-01

    Neutron diffraction study of titanium carbonitridohydride is carried out. It is shown that TiC x N y H z may have a disordered, on ordered and a partially ordered structure depending on the composition. Both in the ordered and in the disordered structure the atoms of carbon and nitrogen are located in octahedron interstices only. Under (C+N)/Ti > 0.70 the atoms of hydrogen are located in octahedron interstices only. Under (C+N)/Ti < 0.50 and under high temperatures the atoms of hydrogen occupy both octahedron and tetrahedron interstices; under low temperatures the transition of some hydrogen atoms from tetrahedron into octahedron interstices is observed. 15 refs.; 1 fig.; 1 tab

  11. High-pressure neutron diffraction study of superhydrated natrolite.

    Science.gov (United States)

    Colligan, Marek; Lee, Yongjae; Vogt, Thomas; Celestian, Aaron J; Parise, John B; Marshall, William G; Hriljac, Joseph A

    2005-10-06

    Neutron powder diffraction data were collected on a sample of natrolite and a 1:1 (v/v) mixture of perdeuterated methanol and water at a pressure of 1.87(11) GPa. The natrolite sample was superhydrated, with a water content double that observed at ambient pressure. All of the water deuterium atoms were located and the nature and extent of the hydrogen bonding elucidated for the first time. This has allowed the calculation of bond valence sums for the water oxygen atoms, and from this, it can be deduced that the key energetic factor leading to loss of the additional water molecule upon pressure release is the poor coordination to sodium cations within the pores.

  12. Neutron diffraction studies of liquid iso-propanol

    International Nuclear Information System (INIS)

    Zetterstroem, P.; Dahlborg, U.; Delaplane, R.G.; Howells, W.S.

    1991-01-01

    The structure of deuterated liquid iso-propanol has been studied with neutron diffraction at the LAD diffractometer at the ISIS spallation source. Measurements were performed at temperatures 190, 220, 250 and 275 K. To correct for inelastic effects a model for the dynamic structure factor which obeys detailed balance and included recoil effects was used. The static molecular structure factor S M (Q) exhibits a pre-peak at about 0.75 A -1 . The origin of the pre-peak, which increases in amplitude with temperature, is presently unknown. The structure of the iso-propanol molecule was obtained from the total pair distribution function and from a fit of the intramolecular form factor f 1 (Q) to the measured S M (Q) at large Q. The obtained values of the bond length and Debye-Waller factors are in good agreement to those obtained from lower alcohols. (orig.)

  13. Neutron diffraction studies of liquid iso-propanol

    Science.gov (United States)

    Zetterström, P.; Dahlborg, U.; Delaplane, R. G.; Howells, W. S.

    1991-07-01

    The structure of deuterated liquid iso-propanol has been studied with neutron diffraction at the LAD diffractometer at the ISIS spallation source. Measurements were performed at temperatures 190, 220, 250 and 275 K. To correct for inelastic effects a model for the dynamic structure factor which obeys detailed balance and included recoil effects was used. The static molecular structure factor SM(Q) exhibits a pre-peak at about 0.75 Å-1. The origin of the pre-peak, which increases in amplitude with temperature, is presently unknown. The structure of the iso-propanol molecule was obtained from the total pair distribution function and from a fit of the intramolecular form factor f1(Q) to the measured SM(Q) at large Q. The obtained values of the bond length and Debye-Waller factors are in good agreement to those obtained from lower alcohols.

  14. Residual stress measurement of welding area by neutron diffraction method

    International Nuclear Information System (INIS)

    Suzuki, Tamaki; Sugiyama, Masaaki; Oikawa, Hatsuhiko; Nose, Tetsuro; Imafuku, Muneyuki; Tomota, Yo; Suzuki, Hiroshi; Moriai, Atsushi

    2010-01-01

    Resistance spot welding technique is extensively applied to join the body steel sheets in the manufacturing process for the automobile industry. It is known that the fatigue crack initiates occasionally inside of the spot-welded zone in this material, which is a serious issue of the fatigue life. Although this phenomenon is supposed to be related to internal residual stress, the actual residual stress distribution inside of the spot-welded zone is not clear up to now. In this study, a neutron diffraction residual stress measurement technique with well-defined sub-mm 3 square gauge volume is applied in order to clarify the internal three dimensional residual stress distribution just below the spot-welded part of the steel sheets. (author)

  15. Neutron diffraction studies of amphipathic helices in phospholipid bilayers

    International Nuclear Information System (INIS)

    Bradshaw, J.P.; Gilchrist, P.J.; Duff, K.C.; Saxena, A.M.

    1994-01-01

    The structural feature which is thought to facilitate the interaction of many peptides with phospholipid bilayers is the ability to fold into an amphipathic helix. In most cases the exact location and orientation of this helix with respect to the membrane is not known, and may vary with factors such as pH and phospholipid content of the bilayer. The growing interest in this area is stimulated by indications that similar interactions can contribute to the binding of certain hormones to their cell-surface receptors. We have been using the techniques of neutron diffraction from stacked phospholipid bilayers in an attempt to investigate this phenomenon with a number of membrane-active peptides. Here we report some of our findings with three of these: the bee venom melittin; the hormone calcitonin; and a synthetic peptide representing the ion channel fragment of influenza A M2 protein

  16. Neutron diffraction studies of amphipathic helices in phospholipid bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Bradshaw, J.P.; Gilchrist, P.J. [Univ. of Edinburgh (United Kingdom); Duff, K.C. [Univ. of Edinburgh Medical School (United Kingdom); Saxena, A.M. [Brookhaven National Laboratory, Upton, NY (United States)

    1994-12-31

    The structural feature which is thought to facilitate the interaction of many peptides with phospholipid bilayers is the ability to fold into an amphipathic helix. In most cases the exact location and orientation of this helix with respect to the membrane is not known, and may vary with factors such as pH and phospholipid content of the bilayer. The growing interest in this area is stimulated by indications that similar interactions can contribute to the binding of certain hormones to their cell-surface receptors. We have been using the techniques of neutron diffraction from stacked phospholipid bilayers in an attempt to investigate this phenomenon with a number of membrane-active peptides. Here we report some of our findings with three of these: the bee venom melittin; the hormone calcitonin; and a synthetic peptide representing the ion channel fragment of influenza A M2 protein.

  17. A neutron diffraction study of ancient Greek ceramics

    Science.gov (United States)

    Siouris, I. M.; Walter, J.

    2006-11-01

    Non-destructive neutron diffraction studies were performed on three 2nd-century BC archaeological pottery fragments from the excavation site of Neos Scopos, Serres, in North Greece. In all the 273 K diagrams quartz and feldspars phase fractions are dominant. Diopside and iron oxide phases were also identifiable. The diopside content is found to decrease with increasing quartz-feldspar compositions. Iron oxides containing minerals were found to be present and the phase compositions reflect upon the coloring of the samples. However, the different content compositions of the phases may suggest different regions of the original clay materials as well as different preparation techniques. The firing temperatures were determined to be in the range of 900-1000 °C.

  18. A neutron diffraction study of ancient Greek ceramics

    International Nuclear Information System (INIS)

    Siouris, I.M.; Walter, J.

    2006-01-01

    Non-destructive neutron diffraction studies were performed on three 2nd-century BC archaeological pottery fragments from the excavation site of Neos Scopos, Serres, in North Greece. In all the 273 K diagrams quartz and feldspars phase fractions are dominant. Diopside and iron oxide phases were also identifiable. The diopside content is found to decrease with increasing quartz-feldspar compositions. Iron oxides containing minerals were found to be present and the phase compositions reflect upon the coloring of the samples. However, the different content compositions of the phases may suggest different regions of the original clay materials as well as different preparation techniques. The firing temperatures were determined to be in the range of 900-1000 deg. C

  19. Development and application of piston-cylinder type clamp cells for neutron diffraction

    International Nuclear Information System (INIS)

    Aso, Naofumi; Fujiwara, Tetsuya; Uwatoko, Yoshiya

    2010-01-01

    Effects of pressure on the physical properties are very important for understanding highly correlated electron systems, in which pressure-induced attractive phenomena such as superconductivity have been observed. In this article, the characteristic features of various materials and pressure transmitting media for use of piston-cylinder type clamp cells are reported. Both CuBe and hybrid CuBe/NiCrAl piston-cylinder-type high-pressure clamp cells were designed for low-temperature neutron diffraction measurements. We also introduce, as the application of the cells, the results of the neutron diffraction under pressure on pressure induced superconductors of UGe 2 and CeRhIn 5 . (author)

  20. Probing hydrogen positions in hydrous compounds: information from parametric neutron powder diffraction studies.

    Science.gov (United States)

    Ting, Valeska P; Henry, Paul F; Schmidtmann, Marc; Wilson, Chick C; Weller, Mark T

    2012-05-21

    We demonstrate the extent to which modern detector technology, coupled with a high flux constant wavelength neutron source, can be used to obtain high quality diffraction data from short data collections, allowing the refinement of the full structures (including hydrogen positions) of hydrous compounds from in situ neutron powder diffraction measurements. The in situ thermodiffractometry and controlled humidity studies reported here reveal that important information on the reorientations of structural water molecules with changing conditions can be easily extracted, providing insight into the effects of hydrogen bonding on bulk physical properties. Using crystalline BaCl2·2H2O as an example system, we analyse the structural changes in the compound and its dehydration intermediates with changing temperature and humidity levels to demonstrate the quality of the dynamic structural information on the hydrogen atoms and associated hydrogen bonding that can be obtained without resorting to sample deuteration.

  1. In-situ neutron diffraction characterization of temperature dependence deformation in α-uranium

    Science.gov (United States)

    Calhoun, C. A.; Garlea, E.; Sisneros, T. A.; Agnew, S. R.

    2018-04-01

    In-situ strain neutron diffraction measurements were conducted at temperature on specimens coming from a clock-rolled α-uranium plate, and Elasto-Plastic Self-Consistent (EPSC) modeling was employed to interpret the findings. The modeling revealed that the active slip systems exhibit a thermally activated response, while deformation twinning remains athermal over the temperature ranges explored (25-150 °C). The modeling also allowed assessment of the effects of thermal residual stresses on the mechanical response during compression. These results are consistent with those from a prior study of room-temperature deformation, indicating that the thermal residual stresses strongly influence the internal strain evolution of grain families, as monitored with neutron diffraction, even though accounting for these residual stresses has little effect on the macroscopic flow curve, except in the elasto-plastic transition.

  2. Modern neutron diffraction methods as a complementary tool to X-ray crystallography for structure research in materials science

    International Nuclear Information System (INIS)

    Heger, Gernot

    2011-01-01

    Neutron diffraction is a well established method in structure research of crystal structures and magnetic ordering. Whereas X-ray diffraction is the standard method for crystal structure determination yielding the total electron density distribution of crystalline materials, neutron diffraction by their nuclear interaction provides the nuclear density distribution and by magnetic dipole interaction the partial electron density distribution of unpaired electrons. Hence neutron crystallography is of special importance for detailed investigations of light elements with few electrons (most prominent example is the hydrogen distribution), to discriminate between different isotopes (e.g. between H and D), and for the determination of magnetic structures and spin density distributions. But neutrons are rare and expensive. There are only a few reactor and spallation sources around the world and the flux of neutron beams is almost 10 -3 smaller than that of a conventional X-ray tube. Therefore, neutron diffractometers and the strategy of data acquisition have to be optimized. Suitable samples, e.g. mm 3 large single crystals are needed, have to be prepared. Examples of modern instrumentation and methods are presented together with results from investigations on structural phase transitions induced by hydrogen-bond ordering (ferroelectric and proton conductor materials) and on complex magnetic systems. It is shown that the combination of X-ray/synchrotron and neutron diffraction is an important tool for a microscopic understanding of physical properties of crystalline materials. (author)

  3. Structure of amorphous selenium studied by neutron diffraction

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Knudsen, Torben Steen; Carneiro, K.

    1975-01-01

    treatment, the neutron scattering cross sections of selenium are determined to be sigmacoh = 8.4±0.1 b and sigmainc = 0.1±0.1 b. Using the fact that S (kappa) for large kappa's is determined by the short distances in the sample, a new method for extrapolation of the experimental S (kappa) until convergence......Neutron diffraction measurements on amorphous selenium have been performed at 293 and 80 K. Careful analyses of the instrumental corrections were made to avoid systematic errors in the measured structure factor S (kappa) in the wave vector region 0 ? kappa ? 12 Å−1. As a result of the data...... is proposed. This allows an accurate determination of g (r) showing peaks at distances that agree well with the previous x−ray experiment by Kaplow et al. for distances up to 11 Å. However, only partial agreement is obtained when finer details of g (r), e.g., the width of the first peak, are considered...

  4. Principles of the measurement of residual stress by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Webster, G.A.; Ezeilo, A.N. [Imperial Coll. of Science and Technology, London (United Kingdom). Dept. of Mechanical Engineering

    1996-11-01

    The presence of residual stresses in engineering components can significantly affect their load carrying capacity and resistance to fracture. In order to quantify their effect it is necessary to know their magnitude and distribution. Neutron diffraction is the most suitable method of obtaining these stresses non-destructively in the interior of components. In this paper the principles of the technique are described. A monochromatic beam of neutrons, or time of flight measurements, can be employed. In each case, components of strain are determined directly from changes in the lattice spacings between crystals. Residual stresses can then be calculated from these strains. The experimental procedures for making the measurements are described and precautions for achieving reliable results discussed. These include choice of crystal planes on which to make measurements, extent of masking needed to identify a suitable sampling volume, type of detector and alignment procedure. Methods of achieving a stress free reference are also considered. A selection of practical examples is included to demonstrate the success of the technique. (author) 14 figs., 1 tab., 18 refs.

  5. Dislocation Characteristics in Lath Martensitic Steel by Neutron Diffraction

    International Nuclear Information System (INIS)

    Harjo, S; Kawasaki, T; Gong, W; Aizawa, K

    2016-01-01

    In situ neutron diffraction during tensile deformation of an as-quenched lath martensitic 22SiMn2TiB steel, was performed using a high resolution and high intensity time- of-flight neutron diffractometer. The characterizations of dislocations were analyzed using the classical Williamson-Hall (cWH) and modified Williamson-Hall (mWH) plots on the breadth method, and the convolutional multiple whole profile (CMWP) fitting method. As results, the dislocation density as high as 10 15 m -2 in the as-quenched martensitic steel was determined. The dislocation density was found to decrease qualitatively with plastic deformation by the cWH and mWH plots, but hardly to change by the CMWP method. The scanning transmission electron microscopy observation supported the results of the latter method. In the CMWP method, the parameter M that represents the arrangement of dislocations was found to decrease rapidly where a very high work hardening was observed. (paper)

  6. Study of ethanol-lysozyme interactions using neutron diffraction

    International Nuclear Information System (INIS)

    Lehmann, M.S.; Mason, S.A.; McIntyre, G.J.

    1985-01-01

    Single-crystal neutron diffraction has been used to observe the interactions between deuterated ethanol (CD3CD2OH) and lysozyme in triclinic crystals of hen egg white lysozyme soaked in 25% (v/v) ethanol solutions. A total of 6047 observed reflections to a resolution of 2 A were used, and 13 possible ethanol sites were identified. The three highest occupied sites are close to locations for bromoethanol found in an earlier study by Yonath et al. [Yonath, A., Podjarny, A., Honig, B., Traub, W., Sielecki, A., Herzberg, O., and Moult, J. (1978) Biophys. Struct. Mech. 4, 27-36]. Structure refinements including a model for the flat solvent lead to a final crystallographic agreement factor of 0.097. Comparison with earlier neutron studies on triclinic lysozyme showed that neither the molecular structure nor the thermal motions were affected significantly by the ethanol. A detailed analysis of the ethanol-lysozyme contacts showed 61% of these to be with hydrophobic sites, in agreement with the dominant hydrophobic nature of ethanol. This, together with the fact that the molecular structure of lysozyme is not perturbed, suggests a model for denaturation of lysozyme by alcohol, which proceeds via a dehydration of the protein at high alcohol concentration

  7. Principles of the measurement of residual stress by neutron diffraction

    International Nuclear Information System (INIS)

    Webster, G.A.; Ezeilo, A.N.

    1996-01-01

    The presence of residual stresses in engineering components can significantly affect their load carrying capacity and resistance to fracture. In order to quantify their effect it is necessary to know their magnitude and distribution. Neutron diffraction is the most suitable method of obtaining these stresses non-destructively in the interior of components. In this paper the principles of the technique are described. A monochromatic beam of neutrons, or time of flight measurements, can be employed. In each case, components of strain are determined directly from changes in the lattice spacings between crystals. Residual stresses can then be calculated from these strains. The experimental procedures for making the measurements are described and precautions for achieving reliable results discussed. These include choice of crystal planes on which to make measurements, extent of masking needed to identify a suitable sampling volume, type of detector and alignment procedure. Methods of achieving a stress free reference are also considered. A selection of practical examples is included to demonstrate the success of the technique. (author) 14 figs., 1 tab., 18 refs

  8. In situ neutron diffraction under high pressure—Providing an insight into working catalysts

    International Nuclear Information System (INIS)

    Kandemir, Timur; Wallacher, Dirk; Hansen, Thomas; Liss, Klaus-Dieter; Naumann d'Alnoncourt, Raoul; Schlögl, Robert; Behrens, Malte

    2012-01-01

    In the present work the construction and application of a continuous flow cell is presented, from which neutron diffraction data could be obtained during catalytic reactions at high pressure. By coupling an online gas detection system, parallel structure and activity investigations of working catalysts under industrial relevant conditions are possible. The flow cell can be operated with different feed gases in a wide range from room temperature to 603 K. Pressures from ambient up to 6 MPa are applicable. An exchangeable sample positioning system makes the flow cell suitable for several different goniomter types on a variety of instrument beam lines. Complementary operational test measurements were carried out monitoring reduction of and methanol synthesis over a Cu/ZnO/Al 2 O 3 catalyst at the high-flux powder diffraction beamline D1B at ILL and high-resolution diffraction beamline Echidna at ANSTO.

  9. In situ neutron diffraction under high pressure—Providing an insight into working catalysts

    Science.gov (United States)

    Kandemir, Timur; Wallacher, Dirk; Hansen, Thomas; Liss, Klaus-Dieter; Naumann d'Alnoncourt, Raoul; Schlögl, Robert; Behrens, Malte

    2012-05-01

    In the present work the construction and application of a continuous flow cell is presented, from which neutron diffraction data could be obtained during catalytic reactions at high pressure. By coupling an online gas detection system, parallel structure and activity investigations of working catalysts under industrial relevant conditions are possible. The flow cell can be operated with different feed gases in a wide range from room temperature to 603 K. Pressures from ambient up to 6 MPa are applicable. An exchangeable sample positioning system makes the flow cell suitable for several different goniomter types on a variety of instrument beam lines. Complementary operational test measurements were carried out monitoring reduction of and methanol synthesis over a Cu/ZnO/Al2O3 catalyst at the high-flux powder diffraction beamline D1B at ILL and high-resolution diffraction beamline Echidna at ANSTO.

  10. Neutron diffraction study of the pressure-induced magnetic ordering in the spin gap system TlCuCl sub 3

    CERN Document Server

    Oosawa, A; Kakurai, K; Fujisawa, M; Tanaka, H

    2003-01-01

    Neutron elastic scattering measurements have been performed under a hydrostatic pressure in order to investigate the spin structure of the pressure-induced magnetic ordering in the spin gap system TlCuCl sub 3. Below the ordering temperature T sub N = 16.9 K for the hydrostatic pressure P = 1.48 GPa, magnetic Bragg reflections were observed at reciprocal lattice points Q = (h, 0, l) with integer h and odd l, which are equivalent to those points with the lowest magnetic excitation energy at ambient pressure. This indicates that the spin gap close due to the applied pressure. The spin structure of the pressure-induced magnetic ordered state for P = 1.48 GPa was determined. (author)

  11. Neutron Diffraction Studies of the Modulated Magnetic Structures of CeSb and Nd Metal

    DEFF Research Database (Denmark)

    Lebech, Bente

    1981-01-01

    The magnetic phase diagram of CeSb, which has been determined by neutron diffraction and other experimental techniques, is briefly reviewed and related to some of the theoretical models that have been developed to account for it. The results of neutron diffraction studies of Nd metal are also...

  12. Mapping residual and internal stress in materials by neutron diffraction

    International Nuclear Information System (INIS)

    Withers, Ph.J.

    2007-01-01

    Neutron diffraction provides one of the few means of mapping residual stresses deep within the bulk of materials and components. This article reviews the basic scientific methodology by which internal strains and stresses are inferred from recorded diffraction peaks. Both conventional angular scans and time-of-flight measurements are reviewed and compared. Their complementarity with analogous synchrotron X-ray methods is also highlighted. For measurements to be exploited in structural integrity calculations underpinning the safe operation of engineering components, measurement standards have been defined and the major findings are summarised. Examples are used to highlight the unique capabilities of the method showing how it can provide insights ranging from the basic physics of slip mechanisms in hexagonal polycrystalline materials, through the materials optimisation of stress induced transformations in smart nano-materials, to the industrial introduction of novel friction welding processes exploiting stress residual measurements transferred from prototype sub-scale tests to the joining of full-scale aero-engine assemblies. (author)

  13. Mapping residual and internal stress in materials by neutron diffraction

    Science.gov (United States)

    Withers, Philip J.

    2007-09-01

    Neutron diffraction provides one of the few means of mapping residual stresses deep within the bulk of materials and components. This article reviews the basic scientific methodology by which internal strains and stresses are inferred from recorded diffraction peaks. Both conventional angular scans and time-of-flight measurements are reviewed and compared. Their complementarity with analogous synchrotron X-ray methods is also highlighted. For measurements to be exploited in structural integrity calculations underpinning the safe operation of engineering components, measurement standards have been defined and the major findings are summarised. Examples are used to highlight the unique capabilities of the method showing how it can provide insights ranging from the basic physics of slip mechanisms in hexagonal polycrystalline materials, through the materials optimisation of stress induced transformations in smart nanomaterials, to the industrial introduction of novel friction welding processes exploiting stress residual measurements transferred from prototype sub-scale tests to the joining of full-scale aeroengine assemblies. To cite this article: P.J. Withers, C. R. Physique 8 (2007).

  14. Diffraction of slow neutrons by holographic SiO2 nanoparticle-polymer composite gratings

    Science.gov (United States)

    Klepp, J.; Pruner, C.; Tomita, Y.; Plonka-Spehr, C.; Geltenbort, P.; Ivanov, S.; Manzin, G.; Andersen, K. H.; Kohlbrecher, J.; Ellabban, M. A.; Fally, M.

    2011-07-01

    Diffraction experiments with holographic gratings recorded in SiO2 nanoparticle-polymer composites have been carried out with slow neutrons. The influence of parameters such as nanoparticle concentration, grating thickness, and grating spacing on the neutron-optical properties of such materials has been tested. Decay of the grating structure along the sample depth due to disturbance of the recording process becomes an issue at grating thicknesses of about 100 microns and larger. This limits the achievable diffraction efficiency for neutrons. As a solution to this problem, the Pendellösung interference effect in holographic gratings has been exploited to reach a diffraction efficiency of 83% for very cold neutrons.

  15. Novel diamond cells for neutron diffraction using multi-carat CVD anvils.

    Science.gov (United States)

    Boehler, R; Molaison, J J; Haberl, B

    2017-08-01

    Traditionally, neutron diffraction at high pressure has been severely limited in pressure because low neutron flux required large sample volumes and therefore large volume presses. At the high-flux Spallation Neutron Source at the Oak Ridge National Laboratory, we have developed new, large-volume diamond anvil cells for neutron diffraction. The main features of these cells are multi-carat, single crystal chemical vapor deposition diamonds, very large diffraction apertures, and gas membranes to accommodate pressure stability, especially upon cooling. A new cell has been tested for diffraction up to 40 GPa with an unprecedented sample volume of ∼0.15 mm 3 . High quality spectra were obtained in 1 h for crystalline Ni and in ∼8 h for disordered glassy carbon. These new techniques will open the way for routine megabar neutron diffraction experiments.

  16. Novel diamond cells for neutron diffraction using multi-carat CVD anvils

    Science.gov (United States)

    Boehler, R.; Molaison, J. J.; Haberl, B.

    2017-08-01

    Traditionally, neutron diffraction at high pressure has been severely limited in pressure because low neutron flux required large sample volumes and therefore large volume presses. At the high-flux Spallation Neutron Source at the Oak Ridge National Laboratory, we have developed new, large-volume diamond anvil cells for neutron diffraction. The main features of these cells are multi-carat, single crystal chemical vapor deposition diamonds, very large diffraction apertures, and gas membranes to accommodate pressure stability, especially upon cooling. A new cell has been tested for diffraction up to 40 GPa with an unprecedented sample volume of ˜0.15 mm3. High quality spectra were obtained in 1 h for crystalline Ni and in ˜8 h for disordered glassy carbon. These new techniques will open the way for routine megabar neutron diffraction experiments.

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

    Science.gov (United States)

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

    2013-01-01

    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 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.

  18. Development of residual stress measurement apparatus by neutron diffraction and its application to bent carbon steel

    International Nuclear Information System (INIS)

    Hayashi, Makoto; Ohkido, Shinobu; Minakawa, Nobuaki; Morii, Yukio

    1998-01-01

    To establish the measuring technique of neutron diffraction for the internal residual stress distribution in a structural component, a neutron diffraction apparatus was designed and manufactured in Modified Japan Research Reactor 3 (JRR3M). At the first step of measurement, a basic characteristics of the diffractometer was evaluated. The incident neutron beam flux was 10 4 n/cm 2 /sec and the Full Width at Half Maximum (FWHM) was about 0.3 degree. This indicates that the manufactured neutron diffractometer is capable for the residual stress measurement. As the first application of the neutron diffraction measurement, the residual stress distribution in plastically bent carbon steel plate was measured. A typical compressive-tensile-compressive-tensile residual stress pattern in the tangential direction in the bent plane was confirmed. The maximum stress near the surface was about 180 MPa. This means that the technique for residual stress measurement by neutron diffraction can be established in Japan. (author)

  19. Pulsed neutron porosity logging system

    International Nuclear Information System (INIS)

    Smith, H.D. Jr.; Smith, M.P.; Schultz, W.E.

    1978-01-01

    An improved pulsed neutron porosity logging system is provided in the present invention. A logging tool provided with a 14 MeV pulsed neutron source, an epithermal neutron detector, and a fast neutron detector is moved through a borehole. Repetitive bursts of neutrons irradiate the earth formations and, during the bursts, the fast neutron population is sampled. During the interval between bursts the epithermal neutron population is sampled along with background gamma radiation due to lingering thermal neutrons. The fast and epithermal neutron population measurements are combined to provide a measurement of formation porosity

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

    International Nuclear Information System (INIS)

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

    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. However, 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%. To demonstrate the capabilities of the facility for elastic scattering studies of liquids, a high quality total structure factor for Zr 64 Ni 36 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)

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

    Science.gov (United States)

    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. However, 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%. 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).

  2. Neutron diffraction analysis of Cr–Ni–Mo–Ti austenitic steel after cold plastic deformation and fast neutrons irradiation

    International Nuclear Information System (INIS)

    Voronin, V.I.; Valiev, E.Z.; Berger, I.F.; Goschitskii, B.N.; Proskurnina, N.V.; Sagaradze, V.V.; Kataeva, N.F.

    2015-01-01

    A quantitative assessment is presented of the dislocation density and relative fractions of edge and screw dislocations in reactor-steel samples 16Cr–15Ni–3Mo–1Ti subjected to preliminary cold deformation by rolling and subsequent fast neutron irradiation using neutron diffraction analysis. The Williamson–Hall modified method was used for calculations. It is shown that the fast neutron irradiation leads to a decrease in the density of dislocations that appeared after samples deformation. The applicability of neutron diffraction analysis to the examination of dislocation structure of deformed and irradiated materials is shown

  3. Neutron diffraction analysis of Cr-Ni-Mo-Ti austenitic steel after cold plastic deformation and fast neutrons irradiation

    Science.gov (United States)

    Voronin, V. I.; Valiev, E. Z.; Berger, I. F.; Goschitskii, B. N.; Proskurnina, N. V.; Sagaradze, V. V.; Kataeva, N. F.

    2015-04-01

    A quantitative assessment is presented of the dislocation density and relative fractions of edge and screw dislocations in reactor-steel samples 16Cr-15Ni-3Mo-1Ti subjected to preliminary cold deformation by rolling and subsequent fast neutron irradiation using neutron diffraction analysis. The Williamson-Hall modified method was used for calculations. It is shown that the fast neutron irradiation leads to a decrease in the density of dislocations that appeared after samples deformation. The applicability of neutron diffraction analysis to the examination of dislocation structure of deformed and irradiated materials is shown.

  4. Neutrons in studies of phospholipid bilayers and bilayer–drug interaction. I. Basic principles and neutron diffraction

    Directory of Open Access Journals (Sweden)

    Belička M.

    2014-12-01

    Full Text Available In our paper, we demonstrate several possibilities of using neutrons in pharmaceutical research with the help of examples of scientific results achieved at our University. In this first part, basic properties of neutrons and elementary principles of elastic scattering of thermal neutrons are described. Results of contrast variation neutron diffraction on oriented phospholipid bilayers with intercalated local anaesthetic or cholesterol demonstrate the potential of this method at determination of their position in bilayers. Diffraction experiments with alkan-1-ols located in the bilayers revealed their influence on bilayer thickness as a function of their alkyl chain length.

  5. Neutron diffraction study of quasi-one-dimensional spin-chain ...

    Indian Academy of Sciences (India)

    Abstract. We report the results of the DC magnetization, neutron powder diffraction and neutron depolarization studies on the spin-chain compounds Ca3Co2−xFexO6 (x = 0,. 0.1, 0.2 and 0.4). Rietveld refinement of neutron powder diffraction patterns at room temperature confirms the single-phase formation for all the ...

  6. Overcoming of the 1/2 reflectivity limit in Laue neutron diffraction

    International Nuclear Information System (INIS)

    Boeuf, A.; Rustichelli, F.; Melone, S.; Puliti, P.

    1978-01-01

    Experimental evidence for the overcoming of the 50% peak reflectivity limit in neutron diffraction in the Laue geometry is presented. Peak reflectivity up to 75%, in spite of the neutron absorption, has been obtained with a bent germanium crystal. This effect has been explained by a simple model based in the dynamical theory of neutron diffraction and appears as a consequence of the elimination, due to a proper curvature, of the Pendelloesung effect. (author)

  7. Qualitative texture investigation of a maraging steel sample by neutron diffraction technique

    International Nuclear Information System (INIS)

    Pugliesi, R.; Yamazaki, I.M.

    1988-08-01

    By means of the neutron diffraction technique the texture of a maraging steel rolled sheet have been determined. The measurements were performed by using a neutron diffractometer installed at the IEA-PI Nuclear Research Reactor, in the beam-hole n 0 6. To avoid corrections such as neutron absorption and sample luminosity the geometric form of the sample was approximated to spheric and its dimensions do not exceed that of neutron beam. The texture of the sample was analysed with help of a computer programm that analyses the intensity of the diffracted neutron beam and plot the pole figure. (author) [pt

  8. Polycrystalline deformation in engineering materials: Insights from neutron diffraction during loading

    International Nuclear Information System (INIS)

    Bourke, M.; Brown, D.

    1999-01-01

    In-situ measurements using the non-destructive penetration of neutrons are commonplace at neutron sources and permit investigations within environmental chambers at stress, pressure, or temperature. Many of these studies explore the microstructural performance of engineering materials under service conditions. For example, by measuring phase strains during the application of static loads, neutron diffraction provides insight into failure, relaxation and load transfer mechanisms. Mechanical loading of a sample on a neutron spectrometer is usually performed with a customized load frame (small enough to fit into the typically limited available space) with the load axis horizontal. Diffraction data are recorded using detectors that surround the sample and strains are determined from changes in the measured interplanar lattice spacings in directions determined by the scattering geometry. These elastic strains indicate how the applied stress is shared throughout the microstructure. During a test, conventional strain gauges also record the macroscopic strain; that is the sum of the plastic and elastic contributions. Beyond yield the plastic contribution usually dominates the total strain but the elastic phase strains respond to the applied stress at any given load and provide clues about which phase (in a multiphase system) or which crystal orientation (in a single phase polycrystal) dictates failure

  9. Sample positioning in neutron diffraction experiments using a multi-material fiducial marker

    Energy Technology Data Exchange (ETDEWEB)

    Marais, D., E-mail: Deon.Marais@necsa.co.za [Research and Development Division, South African Nuclear Energy Corporation (Necsa) SOC Limited, PO Box 582, Pretoria 0001 (South Africa); School of Mechanical and Nuclear Engineering, North-West University, Potchefstroom 2520 (South Africa); Venter, A.M., E-mail: Andrew.Venter@necsa.co.za [Research and Development Division, South African Nuclear Energy Corporation (Necsa) SOC Limited, PO Box 582, Pretoria 0001 (South Africa); Faculty of Agriculture Science and Technology, North-West University, Mahikeng 2790 (South Africa); Markgraaff, J., E-mail: Johan.Markgraaff@nwu.ac.za [School of Mechanical and Nuclear Engineering, North-West University, Potchefstroom 2520 (South Africa); James, J., E-mail: Jon.James@open.ac.uk [Faculty of Mathematics, Computing and Technology, The Open University, Milton Keynes, MK76AA England (United Kingdom)

    2017-01-01

    An alternative sample positioning method is reported for use in conjunction with sample positioning and experiment planning software systems deployed on some neutron diffraction strain scanners. In this approach, the spherical fiducial markers and location trackers used with optical metrology hardware are replaced with a specifically designed multi-material fiducial marker that requires one diffraction measurement. In a blind setting, the marker position can be determined within an accuracy of ±164 µm with respect to the instrument gauge volume. The scheme is based on a pre-determined relationship that links the diffracted peak intensity to the absolute positioning of the fiducial marker with respect to the instrument gauge volume. Two methods for establishing the linking relationship are presented, respectively based on fitting multi-dimensional quadratic functions and a cross-correlation artificial neural network.

  10. Sample positioning in neutron diffraction experiments using a multi-material fiducial marker

    Science.gov (United States)

    Marais, D.; Venter, A. M.; Markgraaff, J.; James, J.

    2017-01-01

    An alternative sample positioning method is reported for use in conjunction with sample positioning and experiment planning software systems deployed on some neutron diffraction strain scanners. In this approach, the spherical fiducial markers and location trackers used with optical metrology hardware are replaced with a specifically designed multi-material fiducial marker that requires one diffraction measurement. In a blind setting, the marker position can be determined within an accuracy of ±164 μm with respect to the instrument gauge volume. The scheme is based on a pre-determined relationship that links the diffracted peak intensity to the absolute positioning of the fiducial marker with respect to the instrument gauge volume. Two methods for establishing the linking relationship are presented, respectively based on fitting multi-dimensional quadratic functions and a cross-correlation artificial neural network.

  11. X-ray structure of perdeuterated diisopropyl fluorophosphatase (DFPase): perdeuteration of proteins for neutron diffraction

    International Nuclear Information System (INIS)

    Blum, Marc-Michael; Tomanicek, Stephen J.; John, Harald; Hanson, B. Leif; Rüterjans, Heinz; Schoenborn, Benno P.; Langan, Paul; Chen, Julian C.-H.

    2010-01-01

    The crystal structure of perdeuterated diisopropyl fluorophosphatase is reported and compared with the hydrogenated structure. Diffraction guidelines for neutron crystallography experiments are summarized. The signal-to-noise ratio is one of the limiting factors in neutron macromolecular crystallography. Protein perdeuteration, which replaces all H atoms with deuterium, is a method of improving the signal-to-noise ratio of neutron crystallography experiments by reducing the incoherent scattering of the hydrogen isotope. Detailed analyses of perdeuterated and hydrogenated structures are necessary in order to evaluate the utility of perdeuterated crystals for neutron diffraction studies. The room-temperature X-ray structure of perdeuterated diisopropyl fluorophosphatase (DFPase) is reported at 2.1 Å resolution. Comparison with an independently refined hydrogenated room-temperature structure of DFPase revealed no major systematic differences, although the crystals of perdeuterated DFPase did not diffract neutrons. The lack of diffraction is examined with respect to data-collection and crystallographic parameters. The diffraction characteristics of successful neutron structure determinations are presented as a guideline for future neutron diffraction studies of macromolecules. X-ray diffraction to beyond 2.0 Å resolution appears to be a strong predictor of successful neutron structures

  12. A comparison of numerical predictions and in-situ neutron diffraction measurements of MMC phase response

    International Nuclear Information System (INIS)

    Lorentzen, T.; Soerensen, N.J.; Liu, Y.L.

    1994-01-01

    Neutron diffraction has been used for in-situ measurements of the phase response of an Al/SiC whisker composite during a tensile test. The in-situ neutron diffraction measurements have been made with a special loading device, which allows for the diffraction measurements to be performed during the tensile test. The measurements are compared with 3D finite element (FEM) simulations using a cell model with a short fiber embedded in the centre of the cell. (au) (14 refs.)

  13. Methods in the determination of partial structure factors of disordered matter by neutron and anomalous X-ray diffraction

    International Nuclear Information System (INIS)

    Suck, J.B.; Chieux, P.; Raoux, D.; Riekel, C.

    1993-01-01

    A general introduction into all possible binary correlations (nuclear-nuclear correlations, mass-mass, charge-charge, nuclear-magnetic, nuclear-electronic, etc.), is followed by methods used in connection with neutron diffraction (and also to neutron inelastic scattering) like isotopic substitution, first and second order difference methods, isomorphic substitution and anomalous neutron diffraction. Then the X-ray anomalous scattering methods used specifically in connection with synchrotron radiation are presented. For both radiation methods and results for wide angle and small angle diffraction are included. Applications of both methods to special systems and problems inherent in these combinations are discussed. Methods and results obtained by computer simulations, Reverse Monte Carlo calculations and a new regularization method used in context with an optimization of compatible data obtained with different methods on the same system, are presented. A translation kit is proposed for semantic purposes between the two domains

  14. Time-of-flight diffraction at pulsed neutron sources: An introduction to the symposium

    International Nuclear Information System (INIS)

    Jorgensen, J.D.

    1994-01-01

    In the 25 years since the first low-power demonstration experiments, pulsed neutron sources have become as productive as reactor sources for many types of diffraction experiments. The pulsed neutron sources presently operating in the United States, England, and Japan offer state of the art instruments for powder and single crystal diffraction, small angle scattering, and such specialized techniques as grazing-incidence neutron reflection, as well as quasielastic and inelastic scattering. In this symposium, speakers review the latest advances in diffraction instrumentation for pulsed neutron sources and give examples of some of the important science presently being done. In this introduction to the symposium, I briefly define the basic principles of pulsed neutron sources, review their development, comment in general terms on the development of time-of-flight diffraction instrumentation for these sources, and project how this field will develop in the next ten years

  15. A preliminary time-of-flight neutron diffraction study of Streptomyces rubiginosus D-xylose isomerase.

    Science.gov (United States)

    Hanson, B Leif; Langan, Paul; Katz, Amy K; Li, Xinmin; Harp, Joel M; Glusker, Jenny P; Schoenborn, Benno P; Bunick, Gerard J

    2004-02-01

    The metalloenzyme D-xylose isomerase forms well ordered crystals that diffract X-rays to ultrahigh resolution (diffraction data has as yet been unable to differentiate between several postulated mechanisms that describe the catalytic activity of this enzyme. Neutrons, with their greater scattering sensitivity to H atoms, could help to resolve this by determining the protonation states within the active site of the enzyme. As the first step in the process of investigating the mechanism of action of D-xylose isomerase from Streptomyces rubiginosus using neutron diffraction, data to better than 2.0 A were measured from the unliganded protein at the Los Alamos Neutron Science Center Protein Crystallography Station. Measurement of these neutron diffraction data represents several milestones: this is one of the largest biological molecules (a tetramer, MW approximately 160 000 Da, with unit-cell lengths around 100 A) ever studied at high resolution using neutron diffraction. It is also one of the first proteins to be studied using time-of-flight techniques. The success of the initial diffraction experiments with D-xylose isomerase demonstrate the power of spallation neutrons for protein crystallography and should provide further impetus for neutron diffraction studies of biologically active and significant proteins. Further data will be measured from the enzyme with bound substrates and inhibitors in order to provide the specific information needed to clarify the catalytic mechanism of this enzyme.

  16. Texture analysis and accuracy of the measurement in cold rolled aluminum sheets using neutron diffraction

    International Nuclear Information System (INIS)

    Park, No Jin; Lee, Moon Kyu; Kim, Sung Jin; Seong, Baek Seok; Lee, Chang Hee; Shin, Eun Joo

    2000-01-01

    The neutron diffraction method is a powerful technique for the texture investigation owing to its high penetration capability, when compared with the X-ray diffraction method. The complete pole figures can be measured and the whole through-thickness texture can be analysed with the neutron diffraction method. Accordingly, the texture measured by means of the neutron diffraction is successfully applied to evaluate the anisotropic properties of the textured materials. Cold rolling of aluminum sheets was carried out with and without lubrication to investigate the formation of inhomogeneous textures as well as to compare the both measurement techniques (neutron and X-ray). The texture of the cold rolled aluminum sheets mainly resides along β-fiber. However, rolling without lubrication led to the formation of the (001)smaller than 110 greater than orientation at the surface layer which was clearly confirmed by X-ray diffraction. With neutron diffraction the whole through-thickness textures were measured. Accuracy of the measurement and texture analysis was estimated using such parameters as RP (hk1) , RP1 (hk1 )-value, PF (hk1) -dispersion and ΔC. It is proved that the texture analysis by the neutron diffraction is more accurate than that by the X-ray diffraction. (author)

  17. Neutron diffraction observations of interstitial protons in dense ice.

    Science.gov (United States)

    Guthrie, Malcolm; Boehler, Reinhard; Tulk, Christopher A; Molaison, Jamie J; dos Santos, António M; Li, Kuo; Hemley, Russell J

    2013-06-25

    The motif of distinct H2O molecules in H-bonded networks is believed to persist up to the densest molecular phase of ice. At even higher pressures, where the molecule dissociates, it is generally assumed that the proton remains localized within these same networks. We report neutron-diffraction measurements on D2O that reveal the location of the D atoms directly up to 52 GPa, a pressure regime not previously accessible to this technique. The data show the onset of a structural change at ∼13 GPa and cannot be described by the conventional network structure of ice VII above ∼26 GPa. Our measurements are consistent with substantial deuteron density in the octahedral, interstitial voids of the oxygen lattice. The observation of this "interstitial" ice VII form provides a framework for understanding the evolution of hydrogen bonding in ice that contrasts with the conventional picture. It may also be a precursor for the superionic phase reported at even higher pressure with important consequences for our understanding of dense matter and planetary interiors.

  18. Neutron diffraction studies for realtime leaching of catalytic Ni

    Science.gov (United States)

    Iles, Gail N.; Devred, François; Henry, Paul F.; Reinhart, Guillaume; Hansen, Thomas C.

    2014-07-01

    The leaching of Al from intermetallic samples of Nickel Aluminium alloys to form Raney-type nickel catalysts is widely used in the hydrogenation industry, however, little is known of the leaching process itself. In this study, the leaching of Al was measured in realtime, in situ, using the high-flux powder neutron diffractometer, D20, at the Institut Laue-Langevin. Despite the liberation of hydrogen and effervescent nature of the reaction the transformation of the dry powder phases into Raney-type Ni was determined. Samples produced by gas-atomisation were found to leach faster than those produced using the cast and crushed technique. Regardless of processing route of the precursor powder, the formation of spongy-Ni occurs almost immediately, while Ni2Al3 and NiAl3 continue to transform over longer periods of time. Small-angle scattering and broadening of the diffraction peaks is an evidence for the formation of the smaller Ni particles. Understanding the kinetics of the leaching process will allow industry to refine production of catalysts for optimum manufacturing time while knowledge of leaching dynamics of powders produced by different manufacturing techniques will allow further tailoring of catalytic materials.

  19. Neutron diffraction studies for realtime leaching of catalytic Ni

    International Nuclear Information System (INIS)

    Iles, Gail N.; Reinhart, Guillaume; Devred, François; Henry, Paul F.; Hansen, Thomas C.

    2014-01-01

    The leaching of Al from intermetallic samples of Nickel Aluminium alloys to form Raney-type nickel catalysts is widely used in the hydrogenation industry, however, little is known of the leaching process itself. In this study, the leaching of Al was measured in realtime, in situ, using the high-flux powder neutron diffractometer, D20, at the Institut Laue-Langevin. Despite the liberation of hydrogen and effervescent nature of the reaction the transformation of the dry powder phases into Raney-type Ni was determined. Samples produced by gas-atomisation were found to leach faster than those produced using the cast and crushed technique. Regardless of processing route of the precursor powder, the formation of spongy-Ni occurs almost immediately, while Ni 2 Al 3 and NiAl 3 continue to transform over longer periods of time. Small-angle scattering and broadening of the diffraction peaks is an evidence for the formation of the smaller Ni particles. Understanding the kinetics of the leaching process will allow industry to refine production of catalysts for optimum manufacturing time while knowledge of leaching dynamics of powders produced by different manufacturing techniques will allow further tailoring of catalytic materials

  20. Neutron diffraction studies for realtime leaching of catalytic Ni.

    Science.gov (United States)

    Iles, Gail N; Devred, François; Henry, Paul F; Reinhart, Guillaume; Hansen, Thomas C

    2014-07-21

    The leaching of Al from intermetallic samples of Nickel Aluminium alloys to form Raney-type nickel catalysts is widely used in the hydrogenation industry, however, little is known of the leaching process itself. In this study, the leaching of Al was measured in realtime, in situ, using the high-flux powder neutron diffractometer, D20, at the Institut Laue-Langevin. Despite the liberation of hydrogen and effervescent nature of the reaction the transformation of the dry powder phases into Raney-type Ni was determined. Samples produced by gas-atomisation were found to leach faster than those produced using the cast and crushed technique. Regardless of processing route of the precursor powder, the formation of spongy-Ni occurs almost immediately, while Ni2Al3 and NiAl3 continue to transform over longer periods of time. Small-angle scattering and broadening of the diffraction peaks is an evidence for the formation of the smaller Ni particles. Understanding the kinetics of the leaching process will allow industry to refine production of catalysts for optimum manufacturing time while knowledge of leaching dynamics of powders produced by different manufacturing techniques will allow further tailoring of catalytic materials.

  1. The impact of deuteration on natural and synthetic lipids: A neutron diffraction study.

    Science.gov (United States)

    Luchini, Alessandra; Delhom, Robin; Demé, Bruno; Laux, Valérie; Moulin, Martine; Haertlein, Michael; Pichler, Harald; Strohmeier, Gernot A; Wacklin, Hanna; Fragneto, Giovanna

    2018-02-05

    The structural investigation of cellular membranes requires access to model systems where the molecular complexity is representative of the cellular environment and that allow for the exploitation of structural techniques. Neutron scattering, and in particular neutron diffraction can provide unique and detailed information on the structure of lipid membranes. However, deuterated samples are desirable to fully exploit this powerful method. Recently, the extraction of lipids from microorganisms grown in deuterated media was demonstrated to be both an attracting route to obtain complex lipid mixtures resembling the composition of natural membranes, and to producing deuterated molecules in a very convenient way. A full characterization of these deuterated extracts is hence pivotal for their use in building up model membrane systems. Here we report the structural characterization of lipid extracts obtained from Pichia pastoris by means of neutron diffraction measurements. In particular, we compare the structure of membranes extracted from yeast cells grown in a standard culture medium and in a corresponding deuterated culture medium. The results show that the different molecular composition of the deuterated and protiated lipid extracts induce different structural organization of the lipid membranes. In addition, we compare these membranes composed of extracted yeast lipids with stacked bilayers prepared from synthetic lipid mixtures. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Production, crystallization and neutron diffraction of fully deuterated human myelin peripheral membrane protein P2.

    Science.gov (United States)

    Laulumaa, Saara; Blakeley, Matthew P; Raasakka, Arne; Moulin, Martine; Härtlein, Michael; Kursula, Petri

    2015-11-01

    The molecular details of the formation of the myelin sheath, a multilayered membrane in the nervous system, are to a large extent unknown. P2 is a peripheral membrane protein from peripheral nervous system myelin, which is believed to play a role in this process. X-ray crystallographic studies and complementary experiments have provided information on the structure-function relationships in P2. In this study, a fully deuterated sample of human P2 was produced. Crystals that were large enough for neutron diffraction were grown by a ten-month procedure of feeding, and neutron diffraction data were collected to a resolution of 2.4 Å from a crystal of 0.09 mm(3) in volume. The neutron crystal structure will allow the positions of H atoms in P2 and its fatty-acid ligand to be visualized, as well as shedding light on the fine details of the hydrogen-bonding networks within the P2 ligand-binding cavity.

  3. Low Temperature In-Situ Stress Measurement of W/Cu Composite by Neutron Diffraction

    Science.gov (United States)

    Nishida, Masayuki; Muslih, M. Rifai; Ikeuchi, Yasukazu; Minakawa, Nobuaki; Hanabusa, Takao

    The internal stresses in the continuous tungsten-fiber reinforced copper-matrix composite were examined by the Neutron stress measurement method. The Neutron diffraction apparatus ND1, which is abbreviated from the Neutron Diffraction system No.1 designed and manufactured by the National Nuclear Energy Agency in Indonesia (Badan Tenage Nuklir Nasional, BATAN), was used in the present study. The most common 3-axes measurement method with Hooke's equation was used to measure stresses in the both of tungsten-fiber and copper-matrix. The tungsten-fiber became the situation of heavy 110 priority orientation. The other hand, copper-matrix became the large crystal grain. Thermal stress alterations caused form low temperature cycling was measured by in-situ stress measurement method making use of a cryostat system. The thermal residual stresses of tungsten-fiber and copper-matrix in longitudinal direction were compressive and tensile state respectively. Results of in-situ thermal stress measurement were agreed with a calculated result of simple elastic theory qualitatively.

  4. Multiple scattering and self-absorption correction for high-pressure neutron diffraction with cylindrical cells

    International Nuclear Information System (INIS)

    Bausenwein, T.; Bertagnolli, H.; Toedheide, K.; Chieux, P.

    1991-01-01

    A formalism for the multiple scattering and self-absorption correction for neutron diffraction experiments with thick-walled cylindrical cells is presented. The formalism, which is based on the optimized Monte Carlo technique, is described. For the isotropic case, secondary scattering coefficients and transmission factors are computed and compared with data from the literature. As a further test, a neutron diffraction experiment was performed on liquid deuterated benzene inside a thick-walled high-pressure cell, using an unusual beam geometry. The scattering of the liquid benzene is evaluated by means of the Monte Carlo program and compared with the result of a standard neutron diffraction experiment. (orig.)

  5. Synchrotron X-ray and neutron diffraction studies in solid-state chemistry

    International Nuclear Information System (INIS)

    Cheetham, A.K.; Wilkinson, A.P.

    1992-01-01

    Since the scatterers are different - X-rays are scattered by the electrons of an atom, neutrons by the nuclei - the questions addressed by the two diffraction experiments have been complementary. For example, neighboring elements of the periodic table could be distinguished formerly only by neutron diffraction. Now, however, this is also partly possible with high-energy synchrotron radiation. This review describes recent applications of X-ray and neutron diffraction methods in solid-state chemistry and how the maximal information can be extracted by a combination of techniques. (orig.)

  6. Neutron diffraction studies of the low-temperature magnetic structure of hexagonal FeGe

    DEFF Research Database (Denmark)

    Bernhard, J.; Lebech, Bente; Beckman, O.

    1984-01-01

    the critical field decreases and the anomaly becomes less pronounced. The cone structure is found to persist up at least 3.9 T, which was the upper limit of the applied field. The neutron diffraction data are discussed and related to previously published macroscopic data (e.g. magnetic susceptibility, torsion......The magnetic structure of the hexagonal polymorph of FeGe has been investigated by means of neutron diffraction on single crystals at low temperature and for magnetic fields applied perpendicular to the c axis. Between 410 and approximately 55K the magnetic structure is collinear c...... and Mossbauer data) as well as to earlier neutron diffraction results....

  7. X-ray and Neutron Diffraction in the Study of Organic Crystalline Hydrates

    Directory of Open Access Journals (Sweden)

    Katharina Fucke

    2010-07-01

    Full Text Available A review. Diffraction methods are a powerful tool to investigate the crystal structure of organic compounds in general and their hydrates in particular. The laboratory standard technique of single crystal X-ray diffraction gives information about the molecular conformation, packing and hydrogen bonding in the crystal structure, while powder X-ray diffraction on bulk material can trace hydration/dehydration processes and phase transitions under non-ambient conditions. Neutron diffraction is a valuable complementary technique to X-ray diffraction and gives highly accurate hydrogen atom positions due to the interaction of the radiation with the atomic nuclei. Although not yet often applied to organic hydrates, neutron single crystal and neutron powder diffraction give precise structural data on hydrogen bonding networks which will help explain why hydrates form in the first place.

  8. X-ray and neutron diffraction in the study of organic crystalline hydrates.

    OpenAIRE

    Fucke, K.; Steed, J.W.

    2010-01-01

    A review. Diffraction methods are a powerful tool to investigate the crystal structure of organic compounds in general and their hydrates in particular. The laboratory standard technique of single crystal X-ray diffraction gives information about the molecular conformation, packing and hydrogen bonding in the crystal structure, while powder X-ray diffraction on bulk material can trace hydration/dehydration processes and phase transitions under non-ambient conditions. Neutron diffraction is a ...

  9. Determination of the nuclear scattering amplitude of uranium-235 isotope by neutron diffraction method

    International Nuclear Information System (INIS)

    Bayvas, F.

    1980-05-01

    The nuclear scattering amplitude of uranium-235 isotope has been determined by the neutron diffraction method. Although the scattering cross section for slow neutrons of uranium-235 is very small (16.33 barns), the coherent scattering can be observed. The scattering amplitude of this isotope has been calculated from the measured diffraction intensities of the enriched metallic uranium as b=(1.05+-0.05)x10 -12 cm. It may possibly give some more idea about the neutron-nucleus interactions of uranium-235 and some other elements which show the same scattering length for slow neutrons. (author)

  10. X-ray structure of perdeuterated diisopropyl fluorophosphatase (DFPase): perdeuteration of proteins for neutron diffraction.

    Science.gov (United States)

    Blum, Marc Michael; Tomanicek, Stephen J; John, Harald; Hanson, B Leif; Rüterjans, Heinz; Schoenborn, Benno P; Langan, Paul; Chen, Julian C H

    2010-04-01

    The signal-to-noise ratio is one of the limiting factors in neutron macromolecular crystallography. Protein perdeuteration, which replaces all H atoms with deuterium, is a method of improving the signal-to-noise ratio of neutron crystallography experiments by reducing the incoherent scattering of the hydrogen isotope. Detailed analyses of perdeuterated and hydrogenated structures are necessary in order to evaluate the utility of perdeuterated crystals for neutron diffraction studies. The room-temperature X-ray structure of perdeuterated diisopropyl fluorophosphatase (DFPase) is reported at 2.1 A resolution. Comparison with an independently refined hydrogenated room-temperature structure of DFPase revealed no major systematic differences, although the crystals of perdeuterated DFPase did not diffract neutrons. The lack of diffraction is examined with respect to data-collection and crystallographic parameters. The diffraction characteristics of successful neutron structure determinations are presented as a guideline for future neutron diffraction studies of macromolecules. X-ray diffraction to beyond 2.0 A resolution appears to be a strong predictor of successful neutron structures.

  11. X-ray structure of perdeuterated diisopropyl fluorophosphatase (DFPase): perdeuteration of proteins for neutron diffraction

    Science.gov (United States)

    Blum, Marc-Michael; Tomanicek, Stephen J.; John, Harald; Hanson, B. Leif; Rüterjans, Heinz; Schoenborn, Benno P.; Langan, Paul; Chen, Julian C.-H.

    2010-01-01

    The signal-to-noise ratio is one of the limiting factors in neutron macromolecular crystallography. Protein perdeuteration, which replaces all H atoms with deuterium, is a method of improving the signal-to-noise ratio of neutron crystallography experiments by reducing the incoherent scattering of the hydrogen isotope. Detailed analyses of perdeuterated and hydrogenated structures are necessary in order to evaluate the utility of perdeuterated crystals for neutron diffraction studies. The room-temperature X-ray structure of perdeuterated diisopropyl fluorophosphatase (DFPase) is reported at 2.1 Å resolution. Comparison with an independently refined hydrogenated room-temperature structure of DFPase revealed no major systematic differences, although the crystals of perdeuterated DFPase did not diffract neutrons. The lack of diffraction is examined with respect to data-collection and crystallo­graphic parameters. The diffraction characteristics of successful neutron structure determinations are presented as a guideline for future neutron diffraction studies of macromolecules. X-ray diffraction to beyond 2.0 Å resolution appears to be a strong predictor of successful neutron structures. PMID:20383004

  12. Compact neutron systems expand in applications. RIKEN RANS

    International Nuclear Information System (INIS)

    Otake, Yoshie

    2017-01-01

    RIKEN accelerator-driven compact neutron source (RANS) has been developed and provided neutrons for industrial use. The proton linac of 7 MeV with the maximum average current 100 μA, pulse width 10-180 μs, repetition frequency 20-200 Hz is used with long-life Be target for such practical use in the field of manufacturing. Corrosion in the painted steels are visualized, neutron imaging and neutron diffraction technique have developed with compact neutron source. Non-destructive visualization inside thick concrete slab has been realized for the social infrastructure safety with compact neutron source system. (author)

  13. Development of a 'pressure composition temperature' (PCT) apparatus for in-situ neutron diffraction studies of hydrides

    International Nuclear Information System (INIS)

    Watson, M.; Shahrukh, A.; Yonkeu, A.L.; Swainson, I.P.; Cranswick, L.

    2006-01-01

    'Full text:' Unlike x-ray diffraction, neutron diffraction unambiguously enables the study of atomic position of hydrogen in hydrides, structural phase transitions between hydride structures, and the ability to discern whether the hydrogen is in solid solution, or in distinct hydrides phases. In-situ neutron diffraction is therefore a critical tool for a fundamental understanding of the mechanism of hydrogen storage, facilitating therefore the development of advanced hydrogen storage materials. NRC-CNBC has designed and built an in-situ neutron apparatus to enable the measurement of the structural state of hydride systems (during hydrogenation or dehydrogenation) with a neutron diffractometer under controlled pressure-temperature conditions. This equipment is designed to be used for up to 9 bar gas pressure and is fully controlled by a computer using Labview software. The temperature range for in-situ neutron diffraction measurements is between 80 and 673K. Three types of gas (hydrogen, deuterium and helium) can be used for experiments with helium being used as a purge gas. The amount of sample for experiments is set to be around 0.8 cc. The apparatus is to be used on the high resolution C2 diffractometer (Chalk River), which is open to Canadian and international research communities. (author)

  14. Neutron Diffraction Studies of a Fully Asymmetric Diffraction Geometry of a Bent Perfect Crystal with the Output Beam Compression

    Czech Academy of Sciences Publication Activity Database

    Mikula, Pavol; Vrána, Miroslav; Šaroun, Jan; Em, V.; Čapek, J.

    2016-01-01

    Roč. 130, č. 4 (2016), s. 1114-1117 ISSN 0587-4246 R&D Projects: GA ČR GB14-36566G; GA MŠk LM2015056 Institutional support: RVO:61389005 Keywords : SANS * neutron diffraction * crystal Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.469, year: 2016

  15. Magnetic ordering in electronically phase-separated La2-xSrxCuO4+y: Neutron diffraction experiments

    DEFF Research Database (Denmark)

    Udby, Linda; Andersen, Niels Hessel; Chou, F.C.

    2009-01-01

    We present results of magnetic neutron diffraction experiments on the codoped superoxygenated La2-xSrxCuO4+y (LSCO+O) system with x=0.09. We find that the magnetic phase is long-range ordered incommensurate antiferromagnetic with a Neacuteel temperature T-N coinciding with the superconducting...

  16. Hydrogen bond nature of ferroelectric material studied by X-ray and neutron diffraction. Electric dipole moment and proton tunneling

    International Nuclear Information System (INIS)

    Noda, Yukio; Kiyanagi, Ryoji; Mochida, Tomoyuki; Sugawara, Tadashi

    2006-01-01

    Hydrogen bond nature of MeHPLN and BrHPLN is studied using x-ray and neutron diffraction technique. We found that electric dipole moment of hydrogen atom plays an important role for the phase transition, and proton tunneling model is confirmed on this isolated hydrogen bond system. (author)

  17. Neutron-Diffraction Study of the Phase Transition in Stannous Chloride Dihydrate

    DEFF Research Database (Denmark)

    Youngblood, R.; Kjems, Jørgen

    1979-01-01

    of the system does not change. We present neutron-diffraction results which show that the temperature dependence of the hydrogen-site occupancies is also highly symmetric around the phase-transition temperature. These results are discussed in terms of a lattice statistical model which was proposed and solved......The order-disorder phase transition in two-dimensional hydrogen-bonded layers of water molecules in SnCl2·2D2O is remarkable in several respects. It has been shown that the peak in the specific heat is highly symmetric around the phase-transition temperature, and that the crystallographic symmetry...

  18. Advanced setup for high-pressure and low-temperature neutron diffraction at hydrostatic conditions

    International Nuclear Information System (INIS)

    Lokshin, Konstantin A.; Zhao Yusheng

    2005-01-01

    We describe a design of the experimental setup for neutron diffraction studies at low temperatures and hydrostatic pressure. The significant benefit of the setup, compared to the previous methods, is that it makes possible the simultaneous collection of neutrons diffracted at the 30 deg. -150 deg. range with no contamination by the primary scattering from the sample surroundings and without cutting out the incident and diffracted beams. The suggested design is most useful for third-generation time-of-flight diffractometers and constant wavelength instruments. Application of the setup expands the capabilities of high-pressure neutron diffraction, allowing time-resolved kinetics and structural studies, multihistogram Rietveld, and pair distribution function and texture analyses. The high efficiency of the setup was proven for the HIPPO diffractometer at Los Alamos Neutron Science Center under pressures up to 10 kbar and temperatures from 4 to 300 K

  19. Study on Destructuring effect of trehalose on water by neutron diffraction

    CERN Document Server

    Branca, C; Migliardo, F; Magazù, V; Soper, A K

    2002-01-01

    In this work results on trehalose/water solutions by neutron diffraction are reported. The study of the partial structure factors and spatial distribution functions gives evidence of a decreasing tetrahedrality degree of water and justifies its cryoprotectant effectiveness. (orig.)

  20. Neutron scattering and diffraction instrument for structural study on biology in Japan

    International Nuclear Information System (INIS)

    Niimura, Nobuo

    1994-01-01

    Neutron scattering and diffraction instruments in Japan which can be used for structural studies in biology are briefly introduced. Main specifications and general layouts of the instruments are shown

  1. Application of the neutron diffraction method to measurements of microstresses and in determination of crystallite size

    International Nuclear Information System (INIS)

    Slomak, M.; Szpunar, J.

    1978-01-01

    Neutron diffraction is used to analyze microstresses and crystallite size. A two 5mm-thick (99,7%) Cu sheeth were joined by welding and investigations were carried out at various distances from the centre of the weald bead

  2. Structural studies at high pressure using time-of-flight neutron powder diffraction

    International Nuclear Information System (INIS)

    Jorgensen, J.D.

    1989-07-01

    Time-of-flight neutron powder diffraction offers unique capabilities for structural studies at high pressure. Scientific applications have included studies of compression mechanisms, new high-pressure structures, and phase transitions. 11 refs., 1 fig

  3. Neutron Diffraction and Magnetostriction of Cubic La(FexAl1-x)13 Intermetallic Compounds

    NARCIS (Netherlands)

    Palstra, T.T.M.; Nieuwenhuys, G.J.; Mydosh, J.A.; Helmholdt, R.B.; Buschow, K.H.J.

    1986-01-01

    The ferromagnetic and antiferromagnetic states of La(FexAl1-x)13 were studied by neutron diffraction and magnetostriction measurements. We present a model for the magnetic structure of the antiferromagnetic state, consisting of ferromagnetic clusters, coupled antiferromagnetically. Magnetostriction

  4. X-ray and neutron diffraction studies of superionic conductors: protonic compounds

    International Nuclear Information System (INIS)

    Tranqui, D.; Anne, M.

    1982-01-01

    Rapid reviews of X-ray and neutron diffraction theories and instrumentations are presented. It is shown that X-ray diffraction is a very powerful tool to determine three dimensional crystal structures. However localization of light atoms by X-ray is somewhat uncertain in compounds containing heavy atoms. In neutron diffraction the irregular but limited variation of scattering lengths of all elements within the periodic table render it possible to localize almost all atoms, especially hydrogen atoms in solids. Some recent and successful studies of protonic compounds and other by X-ray and neutron diffraction are cited. These examples demonstrate that the combined X-ray and neutron techniques should be used to obtain not only geometrical features of rigid framework in superionic conductor materials but also in an indirect way the dynamic properties of mobile ions. (author)

  5. Analysis of magnetic field orientation process of fine particles using neutron diffraction

    International Nuclear Information System (INIS)

    Terada, Noriki

    2010-01-01

    Fine structures in ceramics are important for enhancing the electrical, thermal, optical and mechanical properties of ceramics. Magnetic field alignment of the crystal orientations of fine particles is one of the most effective methods for controlling fine structures. We used neutron diffraction to investigate magnetic alignment of α-Al 2 O 3 fine particles. In situ neutron diffraction measurements of the suspension were performed to investigate the effect of applying a magnetic field. The results revealed that the balance between the magnetic anisotropy energy and thermal fluctuations is critical in determining the crystal orientations of the α-Al 2 O 3 particles in the suspension. Samples were produced by systematically varying the sintering temperature. They were used for neutron diffraction measurements to investigate the effect of sintering. We found that the crystal orientation improves dramatically at temperatures above the grain growth temperature. In this review, we present the experimental details of the neutron diffraction measurements and analyze the results. (author)

  6. Neutron diffraction potentialities at the IBR-2 pulsed reactor for nondestructive testing of structural materials

    International Nuclear Information System (INIS)

    Balagurov, A.M.; Bokuchava, G.D.; Papushkin, I.V.; Sumin, V.V.; Venter, A.M.

    2010-01-01

    Neutron diffraction is widely used for investigations of residual and applied stresses in bulk materials and components. The most important factor in these investigations is the high penetration depth of neutrons (up to 2 cm for steel). At the IBR-2 pulsed reactor in Dubna the Fourier stress diffractometer (FSD) has been constructed to optimize the internal stress measurements. The FSD design satisfies the requirements of high luminosity, high resolution and specific sample environment. The collimator system guarantees a minimum gauge volume of 2x2x2 mm. A mechanical testing machine allows in-situ tension or compression measurements up to a load of 20 kN and sample temperatures up to 800 deg C. In the paper the current status of FSD is reported and potentialities are demonstrated with several examples of investigations performed

  7. Study of magnetic order in CrTe under pressure by neutron diffraction

    International Nuclear Information System (INIS)

    Lambert-Andron, B.; Vettier, C.; Grazhdankina, N.P.

    1978-01-01

    The magnetic compound CrTe was studied by neutron diffraction in a high pressure cell in order to evaluate the magnetic ordering as a function of temperature and pressure. E.S.R. measurements showed that ferromagnetism vanishes above Psub(c)=28 kbar. The neutron diffraction experiments confirmed this disappearance at P>28 kbar; T=100 K; 4.2 K and showed that no new magnetic mode appears. The weak antiferromagnetic component persists with the same order of magnitude [fr

  8. High-resolution neutron diffraction studies of biological and industrial fibres

    Energy Technology Data Exchange (ETDEWEB)

    Langan, P.; Mason, S.A. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France); Fuller, W.; Forsyth, V.T.; Mahendrasingam, A.; Shotton, M.; Simpson, L. [Keele Univ. (United Kingdom); Grimm, H. [FZ, Juelich (Germany); Leberman, R. [EMBL, (Country Unknown)

    1997-04-01

    Neutron diffraction is becoming an important tool for studying fibres due to its complementarity to X-ray diffraction. Unlike X-rays, scattering of neutrons by polymer atoms is not a function of their atomic number. In high-resolution studies (1.5-3 A) on D19 deuteration (replacing H by D) is being used to change the relative scattering power of chosen groups making them easier to locate. Recent studies on DNA and cellulose are described. (author). 6 refs.

  9. Diffraction by the time-of-flight technique at pulsed neutron sources

    International Nuclear Information System (INIS)

    Jorgensen, J.D.

    1984-06-01

    The recent development of accelerator-based pulsed neutron sources as an alternative to reactor sources has caused a renewed interest in time-of-flight neutron diffraction techniques because the time-of-flight method can be optimally used at pulsed sources. Since neutrons have finite mass, and therefore travel at a velocity proportional to their wavelength, neutron diffraction can be done either by the conventional technique commonly used for X-rays, where a single wavelength is used, or by the time-of-flight technique, where all wavelengths are used. In a conventional diffraction experiment with monochromatic radiation, the Bragg equation d = lambda/(2 sin theta) is satisfied by varying the angle 2 theta at which the scattered radiation is detected. In a time-of-flight diffraction experiment, all wavelengths lambda are allowed to scatter from the sample and are determined by recording the times at which neutrons arrive at a detector in a fixed position. Neutron diffraction has been done by the time-of-flight technique for many years using mechanical neutron choppers at reactor sources, but found only limited application because the chopper instruments could not be properly optimized with respect to beam size, pulse width, and repetition rate. The new accelerator-based pulsed neutron sources produce neutrons in short, intense bursts, eliminating the need for mechanical choppers. The pulse width and repetition rate can be tailored to meet the requirements of a particular instrument. After only a few years of development, this has allowed time-of-flight diffraction instruments at moderately-sized pulsed neutron sources

  10. X-ray and neutron diffraction studies of crystallinity in hydroxyapatite coatings.

    Science.gov (United States)

    Girardin, E; Millet, P; Lodini, A

    2000-02-01

    To standardize industrial implant production and make comparisons between different experimental results, we have to be able to quantify the crystallinity of hydroxyapatite. Methods of measuring crystallinity ratio were developed for various HA samples before and after plasma spraying. The first series of methods uses X-ray diffraction. The advantage of these methods is that X-ray diffraction equipment is used widely in science and industry. In the second series, a neutron diffraction method is developed and the results recorded are similar to those obtained by the modified X-ray diffraction methods. The advantage of neutron diffraction is the ability to obtain measurements deep inside a component. It is a nondestructive method, owing to the very low absorption of neutrons in most materials. Copyright 2000 John Wiley & Sons, Inc.

  11. Structure of molten TbCl sub 3 measured by neutron diffraction

    CERN Document Server

    Martin, R A; Barnes, A C; Cuello, G J

    2002-01-01

    The total structure factor of molten TbCl sub 3 at 617 deg. C was measured by using neutron diffraction. The data are in agreement with results from previous experimental work but the use of a diffractometer having an extended reciprocal-space measurement window leads to improved resolution in real space. Significant discrepancies with the results obtained from recent molecular dynamics simulations carried out using a polarizable ion model, in which the interaction potentials were optimized to enhance agreement with previous diffraction data, are thereby highlighted. It is hence shown that there is considerable scope for the development of this model for TbCl sub 3 and for other trivalent metal halide systems spanning a wide range of ion size ratios. (letter to the editor)

  12. Real-time observations of lithium battery reactions-operando neutron diffraction analysis during practical operation.

    Science.gov (United States)

    Taminato, Sou; Yonemura, Masao; Shiotani, Shinya; Kamiyama, Takashi; Torii, Shuki; Nagao, Miki; Ishikawa, Yoshihisa; Mori, Kazuhiro; Fukunaga, Toshiharu; Onodera, Yohei; Naka, Takahiro; Morishima, Makoto; Ukyo, Yoshio; Adipranoto, Dyah Sulistyanintyas; Arai, Hajime; Uchimoto, Yoshiharu; Ogumi, Zempachi; Suzuki, Kota; Hirayama, Masaaki; Kanno, Ryoji

    2016-06-30

    Among the energy storage devices for applications in electric vehicles and stationary uses, lithium batteries typically deliver high performance. However, there is still a missing link between the engineering developments for large-scale batteries and the fundamental science of each battery component. Elucidating reaction mechanisms under practical operation is crucial for future battery technology. Here, we report an operando diffraction technique that uses high-intensity neutrons to detect reactions in non-equilibrium states driven by high-current operation in commercial 18650 cells. The experimental system comprising a time-of-flight diffractometer with automated Rietveld analysis was developed to collect and analyse diffraction data produced by sequential charge and discharge processes. Furthermore, observations under high current drain revealed inhomogeneous reactions, a structural relaxation after discharge, and a shift in the lithium concentration ranges with cycling in the electrode matrix. The technique provides valuable information required for the development of advanced batteries.

  13. Real-time observations of lithium battery reactions—operando neutron diffraction analysis during practical operation

    Science.gov (United States)

    Taminato, Sou; Yonemura, Masao; Shiotani, Shinya; Kamiyama, Takashi; Torii, Shuki; Nagao, Miki; Ishikawa, Yoshihisa; Mori, Kazuhiro; Fukunaga, Toshiharu; Onodera, Yohei; Naka, Takahiro; Morishima, Makoto; Ukyo, Yoshio; Adipranoto, Dyah Sulistyanintyas; Arai, Hajime; Uchimoto, Yoshiharu; Ogumi, Zempachi; Suzuki, Kota; Hirayama, Masaaki; Kanno, Ryoji

    2016-01-01

    Among the energy storage devices for applications in electric vehicles and stationary uses, lithium batteries typically deliver high performance. However, there is still a missing link between the engineering developments for large-scale batteries and the fundamental science of each battery component. Elucidating reaction mechanisms under practical operation is crucial for future battery technology. Here, we report an operando diffraction technique that uses high-intensity neutrons to detect reactions in non-equilibrium states driven by high-current operation in commercial 18650 cells. The experimental system comprising a time-of-flight diffractometer with automated Rietveld analysis was developed to collect and analyse diffraction data produced by sequential charge and discharge processes. Furthermore, observations under high current drain revealed inhomogeneous reactions, a structural relaxation after discharge, and a shift in the lithium concentration ranges with cycling in the electrode matrix. The technique provides valuable information required for the development of advanced batteries. PMID:27357605

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

    International Nuclear Information System (INIS)

    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

  15. Incident spectrum determination for time-of-flight neutron powder diffraction data analysis

    International Nuclear Information System (INIS)

    Hodges, J. P.

    1998-01-01

    Accurate characterization of the incident neutron spectrum is an important requirement for precise Rietveld analysis of time-of-flight powder neutron diffraction data. Without an accurate incident spectrum the calculated model for the measured relative intensities of individual Bragg reflections will possess systematic errors. We describe a method for obtaining an accurate numerical incident spectrum using data from a transmitted beam monitor

  16. Proceedings of the 1986 workshop on advanced time-of-flight neutron powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, A.C.; Smith, K. (comps.)

    1986-09-01

    This report contains abstracts of talks and summaries of discussions from a small workshop held to discuss the future of time-of-flight neutron powder diffraction and its implementation at the Los Alamos Neutron Scattering Center. 47 refs., 3 figs.

  17. Proceedings of the 1986 workshop on advanced time-of-flight neutron powder diffraction

    International Nuclear Information System (INIS)

    Lawson, A.C.; Smith, K.

    1986-09-01

    This report contains abstracts of talks and summaries of discussions from a small workshop held to discuss the future of time-of-flight neutron powder diffraction and its implementation at the Los Alamos Neutron Scattering Center. 47 refs., 3 figs

  18. Neutron diffraction study of quasi-one-dimensional spin-chain ...

    Indian Academy of Sciences (India)

    No extra Bragg peak as well as no observable enhancement in the intensity of the fundamental (nuclear) Bragg peaks has been observed in the neutron diffraction patterns down to 30 K. No depolarization of neutron beam has been observed down to 3 K confirming the absence of ferro- or ferrimagnetic-like correlation.

  19. Neutron diffraction studies on La 2- Dy Ca 2 Ba 2 Cu 4+2

    Indian Academy of Sciences (India)

    Structural studies on Dy-substituted La-2125 type superconductors have been carried out by neutron diffraction experiments at room temperature using a monochromatic neutron beam of wavelength () = 1.249 Å. A series of samples with La2-DyCa2Ba2Cu4+2O stoichiometric composition, for = 0.1-0.5, have ...

  20. In-situ neutron diffraction and acoustic emission investigation of twinning activity in magnesium

    Czech Academy of Sciences Publication Activity Database

    Máthis, K.; Beran, Přemysl; Čapek, J.; Lukáš, Petr

    2012-01-01

    Roč. 340, 012096 (2012), s. 1-6 ISSN 1742-6588. [5th European Conference on Neutron Scattering. Praha, 17.07.2011-21.07.2011] Institutional support: RVO:61389005 Keywords : magnesium alloys * twinning * compression * tension * neutron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism

  1. Influence of multiple small-angle neutron scattering on diffraction peak broadening in ferritic steel

    Czech Academy of Sciences Publication Activity Database

    Woo, W.; Em, V.; Shin, E.; Mikula, Pavol; Ryukhtin, Vasyl

    2015-01-01

    Roč. 48, APR (2015), s. 350-356 ISSN 0021-8898 R&D Projects: GA ČR GB14-36566G; GA MŠk(CZ) LM2011019 Institutional support: RVO:61389005 Keywords : peak broadening * small-angle neutron scattering * neutron diffraction * magnetic domain Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.720, year: 2014

  2. Biochemical profiles of membranes from x-ray and neutron diffraction.

    Science.gov (United States)

    McCaughan, L; Krimm, S

    1982-02-01

    X-ray and neutron diffraction methods provide some information about the distribution of mass in biological membranes and lipid-water systems. Scattering density profiles obtained from these systems, however, usually are not directly interpretable in terms of the relative amounts of chemical constituents (e.g., lipid, protein, and water) as a function of position in the membrane. We demonstrate here that the combined use of x-ray and neutron-scattering profiles, together with information on the total amounts of each of the major membrane components, are sufficient to calculate unambiguously the volume fractions of these components at well-defined regions of the lamellar unit. Three cases are considered: a calculated model membrane pair, dipalmitoylphosphatidylcholine-water multilayers, and rabbit sciatic nerve myelin. For the model system, we discuss the limitations imposed by finite resolution in the diffraction patterns. For the lipid-water multilayers, we calculate water volume fractions in the hydrocarbon tail, lipid headgroup, and interlamellar regions; estimates of these values by various methods are in good agreement with our results. For the nerve myelin, we predict new results for the distribution of protein through the membrane.

  3. New Advances in Neutron Diffraction Studies of Molecular Aqueous Solutions

    OpenAIRE

    Finney, J. L.

    1992-01-01

    Neutron scattering studies have played a major role in improving our understanding of the structures not only of simple single component liquids, but increasingly of mixtures and solutions. In addition to the improved quality of structural information available from neutrons (cf X-rays) resulting from the Q-indcpcndcnt neutron scattering factor and the ability to obtain high resolution information through access to high momentum transfer Q, the use of isotopes allows information at the partia...

  4. Time-of-flight 3D Neutron Diffraction for Multigrain Crystallography

    OpenAIRE

    Cereser, Alberto; Hall, Stephen A.; Steuwer, Axel; Strobl, Markus; Schmidt, Søren

    2016-01-01

    This thesis presents a new technique for measuring spatially resolved microstructures in crystalline materials using pulsed neutron beams. The method, called Time-of-Flight Three Dimensional Neutron Diffraction (ToF 3DND), identifies the position, shape and crystallographic orientation of the individual grains within the sample. The experiments were conducted at the single crystal diffractometer SENJU at the Japanese neutron source J-PARC. The choice of this instrument was motivated by its la...

  5. Residual stress measurement by neutron diffraction inside a steel bar quenched after induction heating

    International Nuclear Information System (INIS)

    Tokuda, Harukiyo; Tomota, Yo; Suzuki, Tetsuya; Kawasaki, Kazuhiro; Moriai, Atsushi; Minakawa, Nobuaki; Morii, Yukio

    2004-01-01

    The residual stress of a quenched steel bar with induction heating was measured by neutron diffraction. The conventional X-ray sin 2 ψ method was also used and three dimensional stress condition was estimated from plane-stress data obtained by a progressive polishing technique. Good agreements were found between the results by the neutron and X-ray methods. Improvements of the neutron stress measurement discussed. (author)

  6. Stress measurement by neutron diffraction method. Standard method using angular dispersion method and trial of using neutron IP

    International Nuclear Information System (INIS)

    Sasaki, Toshihiko; Takago, Shigeki

    2016-01-01

    This paper outlined a stress measurement method using neutrons, and introduced the application examples to stress measurement for metal-based composite materials. In the angular dispersion type measurement using a steady-state reactor type neutron source, the white beams taken out from a nuclear reactor are monochromatized (wavelength λ is a constant value) with a single crystal monochromator and utilized. As an example of measurement, there was the case as follows: the stress of a sintered material which has been put to practical use as valve seat part for automobiles was measured by the neutron method, and the deformation behavior during load was studied. This study performed neutron diffraction measurement using a residual stress analyzer (RESA: Diffractometer for Residual Stress Analysis) installed at JAEA's experimental reactor JRR-3. As a result, it was found that the stress state of the sintered composite material of Fe-Cr and TiN can be predicted with a micromechanics model. A neutron diffraction ring can be obtained using a neutron image plate (IP), where fine powder of gadolinium (Gd) was incorporated into IP for X-rays, and it can be used as an IP reader in the same way as the case of X-rays. A report has been introduced on the examination results of the highly accurate stress measurement by applying the cos α method devised for X-ray stress measurement to neutron diffraction ring. (A.O.)

  7. Implementation of neutron diffraction technique at Nuclear Center of National Institute of Nuclear Research for study of materials

    International Nuclear Information System (INIS)

    Macias Betanzos, L.R.

    1993-01-01

    The Neutron Diffraction technique, it's a helpful tool for the study of materials. The purpose, was to verify that such technique works with the Neutron Diffractometer of National Institute of Nuclear Research. The scope, is to study crystalline materials by the Neutron Diffraction Method, that means it completion with Bragg's Law. There exist a lot of diffraction techniques that depend on the kind of study to do. In this case the study was to measure known samples to have a correlation between parameters such a extinction factor and dislocation density. Known copper deformed samples were measured to observe the extinction effect and it could be observed. We had to calibrate the Neutron Diffractometer, the detection system and to have an optimal movement control of diffractometer devices by mean of a microcomputer. Also, was necessary to control the Reactor TRIGA operation to minimize the neutron flux oscillation. It was not possible the quantification of dislocation density in the samples because the relation signal/background was about one and it gives high inaccuracy. To correct this problem, it's necessary to have a better shielding to minimize the contribution of the background. The conclusion is that the Neutron Diffractometer is in conditions to carry out investigation on the material field, today it can be lattice constants, crystalline phases and measurements of metallic textures. For such studies, it's necessary to have samples with 2 cm 3 or higher to increase the relation signal/background. At present, we have the process software to give the interpretation of the Neutron Diffraction process. (Author). 12 refs, 16 figs

  8. In situ neutron diffraction studies of substructure evolution in metals under uniaxial loading

    International Nuclear Information System (INIS)

    Lukas, P.; Neov, D.; Strunz, P.; Mikula, P.; Vrana, M.; Tomota, Yo; Harjo, S.; Sittner, P.; Novak, V.

    2001-01-01

    Neutron diffraction technique was used for the investigation of internal strains in metals under an external mechanical loading. Besides conventional mechanical response of tested specimens, further microstructural parameters in dependence on the external loading could be extracted from a position, width and shape of individual diffraction profiles by using an appropriate method of the profile analysis. (author)

  9. Longe-Range Order in beta-Brass Studied by Neutron Diffraction

    DEFF Research Database (Denmark)

    Rathmann, Ole; Als-Nielsen, Jens Aage

    1974-01-01

    The long-range order, M(T), in β-brass has been measured by neutron diffraction from a small extinction-free crystal. The results agree with those obtained recently by x-ray diffraction. Near Tc our data are in accordance with a power law M(T)=D(1-T/Tc)β with the critical exponent β=0...

  10. Reinvestigation of the structures of lithium-cobalt-oxides with neutron-diffraction data

    CSIR Research Space (South Africa)

    Gummow, RJ

    1993-11-01

    Full Text Available The structures of LT-LiCoO2 (synthesised by reaction of Li2CO3 and CoCO3 at 400-degrees-C) and its delithiated product LT-Li0.4CoO2 have been reinvestigated by neutron powder diffraction. Despite an unusually close similarity between diffraction...

  11. Determination of magnetic structure of substance based on neutron diffraction experiment data

    International Nuclear Information System (INIS)

    Men'shikov, A.Z.; Vokhmyanin, A.P.; Dorofeev, Yu.A.

    1997-01-01

    The technique based on the experimental neutron diffraction data is developed for determination of the magnetic structure in solid solutions with the high symmetry. The theoretical junction of the elastic magnetic neutron scattering is considered. The examples of definition of magnetic structures of alloys Fe(Pd 1-x Pt) 3 , Fe(Pt 1-x Au) 3 , (Mn 1-x Fe x )Pt, (Fe 1-x Mn x )Pt by means of the proposed method are presented. The neutron diffraction images obtained with the resolution equal to 10 -2 are used for the recognition of the magnetic structures of these alloys [ru

  12. Neutron-diffraction studies of a Cr+0.88 at. % Ga alloy

    Energy Technology Data Exchange (ETDEWEB)

    Venter, A.M. [NECSA, P.O. Box 582, Pretoria 0001 (South Africa); Prinsloo, A.R.E.; Alberts, H.L. [Department of Physics, Rand Afrikaans University, P.O. Box 524, Auckland Park, Johannesburg 2006 (South Africa)

    2002-07-01

    A neutron-diffraction study has been performed on a Cr-Ga alloy single crystal containing 0.88 at. % Ga. Well-defined anomalies were observed in the integrated neutron intensities at the spin-flip as well as at the incommensurate-commensurate spin-density-wave magnetic phase-transition temperatures T{sub sf} and T{sub IC}, respectively. Unusually strong spin-fluctuation effects persist in the crystal to temperatures well above the Neel point. The neutron-diffraction results enhance previous arguments to solve a reported discrepancy between the calculated and directly measured signs of the pressure derivative of T{sub IC}. (orig.)

  13. Novel Experimental Setups for In Situ Neutron Diffraction

    DEFF Research Database (Denmark)

    Ahlburg, Jakob; H. Gjørup, Frederik; Mørch, Mathias

    Modern synchrotron and neutron sources provide the intensities needed for performing never-before-seen experiments. With the imminent launch of the scattering facilities MAX IV & ESS, it is interesting to explore novel setups that enable new experiments at these sites. X-ray and neutron technique...

  14. Non-invasive temperature measurements by neutron diffraction in aero-engine components

    International Nuclear Information System (INIS)

    Holden, T.M.; Root, J.H.; Tennant, D.C.; Leggett, D.

    1995-01-01

    A requirement exists in the aeronautical industry for measuring temperature non-invasively in critical components, such as the turbine disc in an operating engine. Neutron diffraction, unique among nuclear techniques, offers the possibility of measuring both temperature and strain within an operating engine by virtue of the high penetration of neutrons through industrial materials. Static diffraction experiments on Waspaloy and Ti6Al4V showed, by comparison with thermocouples, that both the diffraction peak position and the peak intensity can measure the temperature to within ±6 K at 800 K

  15. Neutron diffraction study of residual strains across electron beam welds in AISI 316L stainless steel

    International Nuclear Information System (INIS)

    Braham, C.; Ceretti, M.; Coppola, R.; Lodini, A.; Rustichelli, F.; Tosto, S.

    1995-01-01

    The results of neutron diffraction investigation of the strains produced across an electron-beam (EB) weld in SA AISI 316L reference steel for NET are presented. The sample size was 10 x 5 x 3 cm 3 and the measurements have been carried out at different distances from the weld plane with a spatial resolution of approximately 8 mm 3 in the bulk of the material. Grain size and crystallographic texture effects were investigated, on the same sample, by means of X-ray diffraction and metallography. A method to determine the stress field from the neutron diffraction data even in the presence of strong texture is discussed. (orig.)

  16. Diffraction and single-crystal elastic constants of Inconel 625 at room and elevated temperatures determined by neutron diffraction

    International Nuclear Information System (INIS)

    Wang, Zhuqing; Stoica, Alexandru D.; Ma, Dong; Beese, Allison M.

    2016-01-01

    In this work, diffraction and single-crystal elastic constants of Inconel 625 have been determined by means of in situ loading at room and elevated temperatures using time-of-flight neutron diffraction. Theoretical models proposed by Voigt, Reuss, and Kroner were used to determine single-crystal elastic constants from measured diffraction elastic constants, with the Kroner model having the best ability to capture experimental data. The magnitude of single-crystal elastic moduli, computed from single-crystal elastic constants, decreases and the single crystal anisotropy increases as temperature increases, indicating the importance of texture in affecting macroscopic stress at elevated temperatures. The experimental data reported here are of great importance in understanding additive manufacturing of metallic components as: diffraction elastic constants are required for computing residual stresses from residual lattice strains measured using neutron diffraction, which can be used to validate thermomechanical models of additive manufacturing, while single-crystal elastic constants can be used in crystal plasticity modeling, for example, to understand mechanical deformation behavior of additively manufactured components.

  17. Work hardening mechanism in high nitrogen austenitic steel studied by in situ neutron diffraction and in situ electron backscattering diffraction

    International Nuclear Information System (INIS)

    Ojima, M.; Adachi, Y.; Tomota, Y.; Ikeda, K.; Kamiyama, T.; Katada, Y.

    2009-01-01

    With a focus on microstructural hierarchy, work hardening behaviour in high nitrogen-bearing austenitic steel (HNS) was investigated mainly by a combined technique of in situ neutron diffraction and in situ electron backscattering diffraction (EBSD). Stress partitioning due to difference in deformability among grains is enhanced in HNS. The larger stress partitioning among [h k l]-oriented family grains seems to realize high work hardening at a small strain. At a larger strain, dislocation density is higher in HNS than in low nitrogen austenitic steel (LNS), which is a possible reason for high work hardening after straining proceeds, resulting in large uniform elongation.

  18. Contribution of neutron diffraction to the study of the texture function of recrystallized titanium, comparison with X-ray diffraction

    International Nuclear Information System (INIS)

    Mardon, J.P.; Pernot, M.; Dervin, P.; Penelle, R.; Englander, M.

    1977-01-01

    Neutron diffraction has been used to obtain complete and formalized direct pole figures of recrystallized titanium sheets; only the transmission method was used for two kinds of samples, the first spherical and the second cylindrical with diameter equal to the height. The orientation distribution function of the crystallites was computed from four measured pole figures. Results of pole figures and of distribution functions are compared with those obtained by X-ray diffraction, by a reflexion-transmission method on a thin sample, and only in reflexion on a composite sample. (Auth.)

  19. Effective vibration isolation system for perfect-crystal neutron interferometry

    International Nuclear Information System (INIS)

    Arthur, J.

    1985-01-01

    Perfect-crystal neutron interferometers are subject to degradation of their performance caused by vibrational accelerations. It is shown that the most seriously offending accelerations are rotational, and an effective and simple vibration isolation system that has been developed at the MIT Neutron Diffraction Laboratory is described

  20. Neutron diffraction by magnetic crystals: V sub 2 O sub 3

    CERN Document Server

    Balcar, E

    2002-01-01

    A theory of neutron scattering by magnetic ions is developed and applied to diffraction by crystals in which ions in the unit cell are not equivalent on account of a lack of translational symmetry in their environments. The development demonstrates a close connection between interpretations of magnetic neutron and x-ray Bragg diffraction, in terms of an atomic model. Cross-sections for neutron diffraction by powders and single crystals, including polarization-induced interference between nuclear and magnetic amplitudes, are considered. By way of illustrating the theoretical development, cross-sections are predicted for Mott-Hubbard insulator, V sub 2 O sub 3 , on the basis of findings from extensive studies using resonant x-ray diffraction.

  1. Angle-dispersive neutron diffraction under high pressure to 10 GPa

    International Nuclear Information System (INIS)

    Klotz, S.; Straessle, Th.; Rousse, G.; Hamel, G.; Pomjakushin, V.

    2005-01-01

    We present a method which allows high-quality powder neutron diffraction patterns to be obtained under pressure by angle-dispersive diffraction to at least 10 GPa. This technique uses a new type of Paris-Edinburgh press in conjunction with sintered boron nitride anvils. As an example, we show NiO diffraction patterns obtained under purely hydrostatic pressures up to 10 GPa. These data were collected within a few hours, and are free from any contaminating signal from the pressure cell. High-resolution nuclear and magnetic structural information can be readily extracted by Rietveld refinements, without additional data correction. This technique will allow powder neutron diffraction at elevated pressures to become a standard tool on continuous neutron facilities

  2. The internal stress measurement the neutron diffraction will bring happiness to your country

    International Nuclear Information System (INIS)

    Minakawa, Nobuaki

    2003-01-01

    The neutron was discovered by Chadwick in 1932. The first reactor was constructed by the USA in 1942. After that, the research and development of reactors advanced. Numbers of reactors were constructed in Europe and in the US. The researches, which use the neutron, were performed actively and excellent results were obtained in wide fields. The penetrating power of the neutron and the neutron diffraction method began to attract attention for the application to the internal stress measurement, too. In Japan, the neutron diffractometer for the residual stress measurement exclusive was installed in the JRR-3M research reactor of JAERI in 1992, and the research was started. At present, we are using it for the stress measurements of the parts of air crafts, railways, automobiles, buildings, machines, home electronics products and so on including nuclear reactors. Reliable science must be introduced in order to support safety and long life operation and to supply them at reasonable cost. Among the various scientific probes to find faults in materials, diffraction technique is used to measure the strain distribution in materials by observing the local changes of the distance between crystallographic planes and the stress distribution is computed to improve manufacturing processes. It is only neutron diffraction that can be used to measure the strain inside the materials. Here, I present an overview of the utilization of neutron scattering research for the industrial uses and the history of the neutron scattering research in JAERI briefly. (J.P.N.)

  3. Texture investigation in aluminium and iron - silicon samples by neutron diffraction technique

    International Nuclear Information System (INIS)

    Pugliese, R.; Yamasaki, J.M.

    1988-09-01

    By means of the neutron diffraction technique the texture of 5% and 98% rolled-aluminium and of iron-silicon steel used in the core of electric transformers, have been determined. The measurements were performed by using a neutron diffractometer installed at the IEA-R1 Nuclear Research Reactor, in the Beam-Hole n 0 . 6. To avoid corrections such as neutron absorption and sample luminosity the geometric form of the samples were approximated to spheric or octagonal prism, and its dimensions do not exceed that of the neutron beam. The texture of the samples were analysed with the help of a computer programme that analyses the intensity of the diffracted neutron beam and plot the pole figures. (author) [pt

  4. Critical points in magnetic systems, a neutron diffraction study of CsCoCl/sub 3/2D/sub 2/O

    Energy Technology Data Exchange (ETDEWEB)

    Bongaarts, A.L.M.

    1975-12-01

    A review is given of the present phenomenological theories of critical points in terms of the scaling -, the universality-, and the smoothness hypothesis. The experimental part describes an investigation by means of thermal neutron scattering to the magnetic phase transitions in the metamagnet CsCoCl/sub 3/.2D/sub 2/0, T/sub N/ = 3.30/sup 0/K. Along the line of critical points, that separates the antiferromagnetic region from the paramagnetic region in the HT-phase diagram, the critical behavior is found both qualitatively and quantitatively in agreement with the predictions of the smoothness hypothesis. A tricritical point is located at T/sub t/ = 1.85/sup 0/K and H/sub t/ = 2.70 k0e, and a full set of tricritical exponents is obtained. It is demonstrated that these exponents are in agreement with the predictions of the scaling hypothesis at a tricritical point, but differ from the classical exponents predicted by recent renormalization group techniques.

  5. Intercalation of single-strand oligonucleotides between nucleolipid anionic membranes: a neutron diffraction study.

    Science.gov (United States)

    Milani, Silvia; Berti, Debora; Dante, Silvia; Hauss, Thomas; Baglioni, Piero

    2009-04-07

    This contribution presents a neutron diffraction investigation of anionic lamellar phases composed of mixtures of 1-palmitoyl, 2-oleoyl phosphatidyl-nucleosides (POPN, where N is either adenosine or uridine), and POPC (1-palmitoyl,2-oleoyl-phosphatidyl-choline). Their behavior is studied for two different mole ratios and in the presence of nucleic acids. The samples are formed by the evaporation of liposomal dispersions prepared in water or in solutions containing single-strand oligonucleotides. Previous small angle X-ray scattering (SAXS) experiments on the system POPA/polyU (polyuridylic acid, high degree of polymerization, synthetic ribonucleic acid) proved that the insertion and ordering of the biopolymer in the phospholipid lamellae were driven by molecular recognition. In the present study, we extend the previous investigation to single-strand monodisperse oligonucleotides (50-mers). Structural details of the membranes were obtained from the analysis of the neutron diffraction scattering length density profiles. The evidence of direct and specific interactions, driven by molecular recognition between the nucleic polar heads of the nucleolipid and the single-strand nucleic acid, is strengthened by the comparison with identically charged bilayers formed by POPG/POPC. These results contribute to the understanding of the parameters governing the interactions between nucleolipid membranes and oligonucleotides, providing a novel strategy for the design of lipid-based vehicles for nucleic acids.

  6. Non-destructive Quantitative Phase Analysis and Microstructural Characterization of Zirconium Coated U-10Mo Fuel Foils via Neutron Diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Cummins, Dustin Ray [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vogel, Sven C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hollis, Kendall Jon [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Brown, Donald William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dombrowski, David E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-10-18

    This report uses neutron diffraction to investigate the crystal phase composition of uranium-molybdenum alloy foils (U-10Mo) for the CONVERT MP-1 Reactor Conversion Project, and determines the effect on alpha-uranium contamination following the deposition of a Zr metal diffusion layer by various methods: plasma spray deposition of Zr powders at LANL and hot co-rolling with Zr foils at BWXT. In summary, there is minimal decomposition of the gamma phase U-10Mo foil to alpha phase contamination following both plasma spraying and hot co-rolling. The average unit cell volume, i.e. lattice spacing, of the Zr layer can be mathematically extracted from the diffraction data; co-rolled Zr matches well with literature values of bulk Zr, while plasma sprayed Zr shows a slight increase in the lattice spacing, indicative of interstitial oxygen in the lattice. Neutron diffraction is a beneficial alternative to conventional methods of phase composition, i.e. x ray diffraction (XRD) and destructive metallography. XRD has minimal penetration depth in high atomic number materials, particularly uranium, and can only probe the first few microns of the fuel plate; neutrons pass completely through the foil, allowing for bulk analysis of the foil composition and no issues with addition of cladding layers, as in the final, aluminum-clad reactor fuel plates. Destructive metallography requires skilled technicians, cutting of the foil into small sections, hazardous etching conditions, long polishing and microscopy times, etc.; the neutron diffraction system has an automated sample loader and can fit larger foils, so there is minimal analysis preparation; the total spectrum acquisition time is ~ 1 hour per sample. The neutron diffraction results are limited by spectra refinement/calculation times and the availability of the neutron beam source. In the case of LANSCE at Los Alamos, the beam operates ~50% of the year. Following the lessons learned from these preliminary results, optimizations to

  7. A neutron well logging system

    International Nuclear Information System (INIS)

    1980-01-01

    A pulsed neutron well logging system using a sealed off neutron generator tube is provided with a programmable digital neutron output control system. The control system monitors the target beam current and compares a function of this current with a pre-programmed control function to develop a control signal for the neutron generator. The control signal is used in a series regulator to control the average replenisher current of the neutron generator tube. The programmable digital control system of the invention also provides digital control signals as a function of time to provide ion source voltages. This arrangement may be utilized to control neutron pulses durations and repetition rates or to produce other modulated wave forms for intensity modulating the output of the neutron generator as a function of time. (Auth.)

  8. Determination of austenite vs. α-ferrite in steel by neutron and X-ray diffraction

    International Nuclear Information System (INIS)

    Als-Nielsen, J.; Clausen, K.

    1984-06-01

    Neutron and X-ray diffraction studies for determining the relative content of fcc (austenite) and bcc (α-ferrite) phases in steel samples are reported. In addition to determine the relative content of phases the diffraction method also provides information about the strain fields in the sample by the concomitant broadening of diffraction peaks. Neutron diffraction has the advantage that large sample volumes (several cc) are probed, and the effect of texture can thus be eliminated. X-ray diffraction patterns can be registered in a short time thus allowing kinetic studies of phase changes during heat treatment or mechanical treatment. In addition it is possible to probe different surface thickness by utilizing different X-ray wavelengths. Measurements of this type can be carried out on a commercial contract basis in the Solid State Physics Division at Risoe National Laboratory. (author)

  9. Determination of crystalline texture in aluminium - uranium alloys by neutron diffraction

    International Nuclear Information System (INIS)

    Azevedo, A.M.V. de.

    1978-01-01

    Textures of hot-rolled aluminum-uranium alloys and of aluminum were determined by neutron diffraction. Sheets of alloys containing 8.0, 21.5 and 23.7 wt pct U, as well as pure aluminum, were obtained in a stepped rolling process, 15% reduction each step, 75% total reduction. During the rolling the temperature was 600 0 C. Alloys with low uranium contents are two phase systems in which an intermetallic compound UAl 4 , orthorhombic, is dispersed in a pure aluminum matrix. The addition of a few percent of Si in such alloys leads to the formation of UAl 3 , simple cubic, instead of UAl 4 . The Al -- 23.7 wt pct U alloy was prepared with 2,2 wt pct of Si. The results indicate that the texture of the matrix is more dependent on the uranium concentration than on the texture of the intermetallic phases. An improvement in the technique applied to texture measurements by using a sample fully bathed in the neutron beam is also presented. The method takes advantage of the low neutron absorption of the studied materials as well as of the neglibible variation in the multiple scattering which occurs in a conveniently shaped sample having a weakly developed texture. (Author) [pt

  10. Residual stress distribution in carbon steel pipe welded joint measured by neutron diffraction

    International Nuclear Information System (INIS)

    Hayashi, Makoto; Ishiwata, Masayuki; Morii, Yukio; Minakawa, Nobuaki

    2000-01-01

    In order to estimate crack growth behavior of fatigue and stress corrosion cracking in pipes, the residual stress distribution near the pipe weld region has to be measured through the wall thickness. Since the penetration depth of neutron is deep enough to pass through the thick pipe wall, the neutron diffraction technique for the residual stress measurement is effective for this purpose. At the first step the residual stress distribution near the weld region in a butt-welded carbon steel pipe was measured by the neutron diffraction. Significant stresses extended only to a distance of 30 mm from the center of the weld. The major tensile stresses occurred in the hoop direction in the fusion and heat affected zones of the weldment, and they attained a level greater than 200 MPa through the thickness. While the axial residual stress at the inside surface was 50 MPa, the stress at the outside surface was -100 MPa. The comparison of residual stress distributions measured by the neutron diffraction, the X-ray diffraction and the strain gauge method reveals that the neutron diffraction is the most effective for measuring the residual stress inside the structural components. (author)

  11. A preliminary neutron diffraction study of rasburicase, a recombinant urate oxidase enzyme, complexed with 8-azaxanthin

    Energy Technology Data Exchange (ETDEWEB)

    Budayova-Spano, Monika, E-mail: spano@embl-grenoble.fr [European Molecular Biology Laboratory Grenoble Outstation, 6 Rue Jules Horowitz, 38042 Grenoble (France); Institut Laue-Langevin, 6 Rue Jules Horowitz, BP 156, 38042 Grenoble (France); Bonneté, Françoise; Ferté, Natalie [Centre de Recherche en Matière Condensée et Nanosciences, Campus de Luminy, Case 913, 13288 Marseille (France); El Hajji, Mohamed [Sanofi-Aventis, 371 Rue du Professeur Blayac, 34184 Montpellier (France); Meilleur, Flora [Institut Laue-Langevin, 6 Rue Jules Horowitz, BP 156, 38042 Grenoble (France); Blakeley, Matthew Paul [European Molecular Biology Laboratory Grenoble Outstation, 6 Rue Jules Horowitz, 38042 Grenoble (France); Castro, Bertrand [Sanofi-Aventis, 371 Rue du Professeur Blayac, 34184 Montpellier (France); European Molecular Biology Laboratory Grenoble Outstation, 6 Rue Jules Horowitz, 38042 Grenoble (France)

    2006-03-01

    Neutron diffraction data of hydrogenated recombinant urate oxidase enzyme (Rasburicase), complexed with a purine-type inhibitor 8-azaxanthin, was collected to 2.1 Å resolution from a crystal grown in D{sub 2}O by careful control and optimization of crystallization conditions via knowledge of the phase diagram. Deuterium atoms were clearly seen in the neutron-scattering density map. Crystallization and preliminary neutron diffraction measurements of rasburicase, a recombinant urate oxidase enzyme expressed by a genetically modified Saccharomyces cerevisiae strain, complexed with a purine-type inhibitor (8-azaxanthin) are reported. Neutron Laue diffraction data were collected to 2.1 Å resolution using the LADI instrument from a crystal (grown in D{sub 2}O) with volume 1.8 mm{sup 3}. The aim of this neutron diffraction study is to determine the protonation states of the inhibitor and residues within the active site. This will lead to improved comprehension of the enzymatic mechanism of this important enzyme, which is used as a protein drug to reduce toxic uric acid accumulation during chemotherapy. This paper illustrates the high quality of the neutron diffraction data collected, which are suitable for high-resolution structural analysis. In comparison with other neutron protein crystallography studies to date in which a hydrogenated protein has been used, the volume of the crystal was relatively small and yet the data still extend to high resolution. Furthermore, urate oxidase has one of the largest primitive unit-cell volumes (space group I222, unit-cell parameters a = 80, b = 96, c = 106 Å) and molecular weights (135 kDa for the homotetramer) so far successfully studied with neutrons.

  12. Structure of drug-target proteins determined by both X-ray and neutron diffraction

    International Nuclear Information System (INIS)

    Kuroki, Ryota

    2009-01-01

    Crystallography enables us to obtain accurate atomic positions within proteins. High resolution X-ray crystallography provides information for most of the atoms comprising a protein, with the exception of hydrogens. Neutron diffraction data can provide information of the location of hydrogen atoms to the structural information determined by X-ray crystallography. Here, we show the recent of the structural determination of drug-target proteins, porcine pancreatic elastase (PPE) and human immuno-deficiency virus type-1 protease (HIV-PR) by both X-ray and neutron diffraction. The structure of porcine pancreatic elastase with its potent inhibitor (FR13080) was determined to 0.94A resolution by X-ray diffraction and 1.75 A resolution by neutron diffraction. It was found that there are two characteristic hydrogen bonding interactions in which hydrogen atoms were confirmed. One is located between a catalytic aspartate and histidine, another is involved in the inhibitor recognition site. The structure of HIV-PR with its potent inhibitor (KNI-272) was also determined to 0.93 A resolution by X-ray diffraction and 2.3 A resolution by neutron diffraction. The ionization state of the catalytic residues were clarified to show that Asp125 is protonated and Asp25 is deprotonated. The ionization state and the location of hydrogen atoms of the catalytic residue in HIV-PR were firstly determined by neutron diffraction. Furthermore, collaborative use of both X-ray and neutron to identify the location of ambiguous hydrogen atoms will be shown. (author)

  13. Neutron diffraction studies on ordered and disordered materials

    International Nuclear Information System (INIS)

    Krishna, P.S.R

    2016-01-01

    Knowledge of the symmetry and distribution of atoms in the unit cell and the bonding between atoms is the key point for understanding, designing and manipulating chemical behavior or physical properties of novel materials for technological applications. This could be achieved using diffraction techniques. At the Dhruva national facility, BARC, Mumbai, a Powder diffractometer (PD2) and a High-Q diffractometer (HQD) are in operation for more than 2 decades. PD2 and HQD are equipped with banks of 5 and 10 position sensitive detectors (PSD) respectively, to cover the Q-ranges 9.4 Å -1 and 15 Å -1 respectively. The resolutions (Δd/d) of these instruments are 0.8% (λ = 1.24 Å) and 2.5% (λ = 0.78 Å). We report about the studies of changes in the long range order in crystalline materials as a function of temperature and/or composition as well as short and intermediate range orders studied in amorphous materials on these diffractometers in recent years. PD2 has been extensively used in the structural/phase transition studies of ferroics, multiferroics, nanoferrites along with magnetic structure determinations. On the other hand, HQD has been extensively used to understand the short and intermediate range order in network glasses like chalcogenides, H-bonded alcohols, Telluride glasses etc. We will be discussing the recent structural results obtained on many of these crystalline systems, glasses and molecular fluids on both of these diffractometers. (author)

  14. Neutron Diffraction Cryoporometry - A measurement technique for studying mesoporous materials and the phases of contained liquids and their crystalline forms

    OpenAIRE

    Webber, J. Beau W.; Dore, John C.

    2008-01-01

    Neutron diffraction is a standard method for determining the structure\\ud of matter on an atomic scale; NMR cryoporometry is a recent widely applicable technique for characterising structure on a 2 nm to 2 mu m scale. An extension of these techniques is described, Neutron Diffraction Cryoporometry (NDC). The information from a set of neutron\\ud diffraction measurements of liquids and their crystalline forms in meso-pores, as a function of temperature, is displayed as a cryoporometry graph. Th...

  15. Neutron and X-ray diffraction from modulated structures

    International Nuclear Information System (INIS)

    Harris, P.

    1994-07-01

    This thesis describes X-ray and neutron scattering experiments performed on two examples of modulated structures. After an introduction to the subject of modulated structures, the thesis is divided in three parts. A single crystal elastic neutron scattering experiment between 4.2 and 115 Κ has been performed and four-circle X-ray data have been collected at 8 Κ for the monoclinic low-temperature phase of the layered perovskite PAMC. The results from the neutron scattering experiment indicate that magnetoelastic effects influence the ordering of the crystal. The X-ray experiments have made it possible to determine the crystal structure in the low-temperature phase. The superspace group is P2 1 /b(β-30)Os, with β = 1/3. A small-angle neutron scattering experiment has been performed on the magnetic structure of manganese silicide. When a magnetic field is applied, the modulation vectors turn towards the field direction, showing domain growth and diverging peak widths as they approach the field direction. Phase 'A' is established to have the modulation vectors directed perpendicular to the field direction. Cooling in zero field shows increasing peak widths at low temperatures, indicating a lock-in transition below the lowest reached temperature. To be able to analyse the data of the magnetic order in MnSi, and analytical calculation of the three dimensional resolution function for a small-angle neutron scattering spectrometer has been performed. The calculation is done by application of a combination of phase space analysis and Gaussian approximations for the neutron distribution as well as for the transmission functions of the different apertures. A finite mosaic spread of the crystal and finite correlation widths of the Bragg reflections have been included in the cross section. (au) (3 tabs., 48 ills., 100 refs.)

  16. Rietveld refinement of In{sub 2}S{sub 3} using neutron and X-ray powder diffraction data

    Energy Technology Data Exchange (ETDEWEB)

    Rampersadh, Niyum S.; Venter, Andrew M.; Billing, David G

    2004-07-15

    Powder neutron and X-ray diffraction data for indium sulfide are reported. The lattice parameters obtained from a Rietveld refinement for the neutron data are: a=7.5937 (6) A; c=32.352 (3) A; V=1865.6 (3) A{sup 3} and for X-ray data are: a=7.6172 (1) A; c=32.3307 (8) A; V=1875.86 (6) A{sup 3}. The crystal system was taken to be tetragonal (space group I4{sub 1}/amd)

  17. Area detectors in single-crystal neutron diffraction

    Science.gov (United States)

    McIntyre, Garry J.

    2015-12-01

    The introduction of area detectors has brought about a gentle revolution in the routine application of single-crystal neutron diffractometry. Implemented first for macromolecular crystallography, electronic detectors subsequently gradually spread to chemical and physics-oriented crystallography at steady-state sources. The volumetric surveying of reciprocal space implicit in the Laue technique has required area detectors right from the start, whether using film and more recently image plates and CCD-based detectors at reactors, or scintillation detectors at spallation sources. Wide-angle volumetric data collection has extended application of neutron single-crystal diffractometry to chemical structures, sample volumes, and physical phenomena previously deemed impossible. More than 30 of the dedicated single-crystal neutron diffractometers at steady-state reactor and neutron spallation sources worldwide and accessible via peer-review proposal mechanisms are currently equipped with area detectors. Here we review the historical development of the various types of area detectors used for single crystals, discuss experimental aspects peculiar to experiments with such detectors, highlight the scientific fields where the use of area detectors has had a special impact, and forecast future developments in hardware, implementation, and software.

  18. Area detectors in single-crystal neutron diffraction

    International Nuclear Information System (INIS)

    McIntyre, Garry J

    2015-01-01

    The introduction of area detectors has brought about a gentle revolution in the routine application of single-crystal neutron diffractometry. Implemented first for macromolecular crystallography, electronic detectors subsequently gradually spread to chemical and physics-oriented crystallography at steady-state sources. The volumetric surveying of reciprocal space implicit in the Laue technique has required area detectors right from the start, whether using film and more recently image plates and CCD-based detectors at reactors, or scintillation detectors at spallation sources. Wide-angle volumetric data collection has extended application of neutron single-crystal diffractometry to chemical structures, sample volumes, and physical phenomena previously deemed impossible. More than 30 of the dedicated single-crystal neutron diffractometers at steady-state reactor and neutron spallation sources worldwide and accessible via peer-review proposal mechanisms are currently equipped with area detectors. Here we review the historical development of the various types of area detectors used for single crystals, discuss experimental aspects peculiar to experiments with such detectors, highlight the scientific fields where the use of area detectors has had a special impact, and forecast future developments in hardware, implementation, and software. (review)

  19. Tensile deformation behaviors of Zircaloy-4 alloy at ambient and elevated temperatures: In situ neutron diffraction and simulation study

    International Nuclear Information System (INIS)

    Li, Hongjia; Sun, Guangai; Woo, Wanchuck; Gong, Jian; Chen, Bo; Wang, Yandong; Fu, Yong Qing; Huang, Chaoqiang; Xie, Lei; Peng, Shuming

    2014-01-01

    Tensile stress–strain relationship of a rolled Zircaloy-4 (Zr-4) plate was examined in situ using a neutron diffraction method at room temperature (RT, 25 °C) and an elevated temperature (250 °C). Variations of lattice strains were obtained as a function of macroscopic bulk strains along prismatic (101 ¯ 0), basal (0 0 0 2) and pyramidal (101 ¯ 1) planes in the hexagonal close-packed structure of the Zr-4. The mechanisms of strain responses in these three major planes were simulated using elastic–plastic self-consistent (EPSC) model based on Hill–Hutchinson method, thus the inter-granular stresses and deformation systems of each individual grain under loading were obtained. Results show that there is a good agreement between the EPSC modeling and neutron diffraction measurements in terms of macroscopic stress–strain relationship and lattice strain evolutions of the planes at RT. However, there is a slight discrepancy in the lattice strains obtained from the EPSC modeling and neutron diffraction when the specimen was deformed at 250 °C. Analysis of grain structure and texture obtained using electron back-scattered diffraction suggests that dynamic recovery process is significant during the tensile deformation at the elevated temperature, which was not considered in the simulation

  20. Random-walk algorithm for the simulation of neutron diffraction in deformed mosaic crystals

    Czech Academy of Sciences Publication Activity Database

    Šaroun, Jan

    2004-01-01

    Roč. 529, č. 1 (2004), s. 162-165 ISSN 0168-9002 R&D Projects: GA ČR GA202/03/0891; GA AV ČR IAA1048003 Institutional research plan: CEZ:AV0Z1048901 Keywords : Monte Carlo simulations * neutron diffraction * neutron monochromators Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.349, year: 2004

  1. Through-thickness Residual Stress Measurement by Neutron Diffraction in Cu+W Plasma Spray Coatings

    Czech Academy of Sciences Publication Activity Database

    Luzin, V.; Matějíček, Jiří; Gnäupel-Herold, T.

    2010-01-01

    Roč. 652, č. 652 (2010), s. 50-56 ISSN 1662-9752. [International Conference on Mechanical Stress Evaluation by Neutrons and Synchrotron Radiation/5th./. Mito, 10.11.2009-12.11.2009] R&D Projects: GA MŠk ME 901 Institutional research plan: CEZ:AV0Z20430508 Keywords : fusion materials * plasma sprayed coatings * residual stress * neutron diffraction Subject RIV: JG - Metallurgy http://www.scientific.net/MSF.652.50

  2. Residual strain and stress measurements by neutron diffraction in the industry

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    2011-01-01

    The residual stress remarkably affects fracture strength, fatigue strength and stress corrosion cracking. It is very much important to measure the residual stresses in the materials in order to secure the reliability of structure. One of the big characteristics of neutron is large penetration depth. This feature enables to measure the residual strain or stress inside of structural components and machine parts. In this paper, several industrial applications of residual stress and strain measurements by neutron diffraction would be introduced. (author)

  3. Neutron diffraction study of ordering of atoms and antiphase domains in titanium carbohydrides

    International Nuclear Information System (INIS)

    Mukhtarova, N. N.; Getmanskiy, V. V.

    2004-01-01

    Hydrogen effects greatly properties and structure of refractory titanium carbide which is essential in the technique described. To obtain carbohydrides with the largest concentrations of hydrogen and Ti carbides that have given service characteristics, structural features of these materials should be known. In the present work the Ti carbohydrides of different compositions at the lower limit of homogeneity range were studied by means of X-ray and powder neutron diffraction. Neutron diffraction patterns were obtained using the neutron diffractometer mounted at the thermal column of the atomic reactor of the INP AS RUz (λ = 1.085 A). The treatment of neutron diffraction patterns was carried out by the Rietweld full-profile analysis (program of DBW 3.2). Samples of carbohydrides TiC x H y were prepared by mean sintering. Treatment of samples was carried out in evacuated and sealed quartz ampoules, thus preventing hydrogen escape from the samples. Concentration of carbon and hydrogen atoms in the samples was controlled by chemical and neutron diffraction analysis. This work was supported by the Center of Science and Technology of Uzbekistan (contract Φ - 2.1.2)

  4. Neutron diffraction analysis of Pseudomonas aeruginosa peptidyl-tRNA hydrolase 1.

    Science.gov (United States)

    McFeeters, Hana; Vandavasi, Venu Gopal; Weiss, Kevin L; Coates, Leighton; McFeeters, Robert L

    2016-03-01

    Perdeuterated peptidyl-tRNA hydrolase 1 from Pseudomonas aeruginosa was crystallized for structural analysis using neutron diffraction. Crystals of perdeuterated protein were grown to 0.15 mm(3) in size using batch crystallization in 22.5% polyethylene glycol 4000, 100 mM Tris pH 7.5, 10%(v/v) isopropyl alcohol with a 20-molar excess of trilysine as an additive. Neutron diffraction data were collected from a crystal at room temperature using the MaNDi single-crystal diffractometer at Oak Ridge National Laboratory.

  5. Study of the texture and stored energy of stainless steels by using neutron diffraction

    International Nuclear Information System (INIS)

    Shin, Eunjoo; Seong, Baek-Seok; Park, Soo Ho; Kim, Hark-Rho

    2006-01-01

    The texture of 400 series stainless steels was investigated by using neutron diffraction and the calculated R-values from the texture were compared with the experimental R-values. Cold rolled samples with different reduction rates were used to investigate the effect of the cold rolling reduction rate on the formability. Also, the stored energies of the cold rolled samples were relatively evaluated by using neutron diffraction. The R-value of the recrystallized samples revealed similar values after an 80% reduction, and the stored energy of the cold rolled samples presented the same results

  6. In situ neutron-diffraction study of tensile deformation of a bulk nanocrystalline alloy

    International Nuclear Information System (INIS)

    Fan, G.J.; Li, L.; Yang, Bin; Choo, H.; Liaw, P.K.; Saleh, T.A.; Clausen, B.; Brown, D.W.

    2009-01-01

    In situ neutron-diffraction technique has been employed to study the uniaxial tensile deformation of a bulk nanocrystalline Ni-Fe alloy. In contrast to an increase in the full-width half-maximum (FWHM) of the neutron-diffraction patterns for the coarse-grained Ni, the FWHM for the nanocrystalline Ni-Fe alloy decreases with increasing the plastic strain, ε P . The deformation with ε P < 1.5% did not introduce a residual lattice strain and a texture in the nanocrystalline Ni-Fe alloy, which were otherwise developed in the coarse-grained Ni

  7. In situ neutron diffraction study of the nickel oxihydroxide electrode upon discharge

    International Nuclear Information System (INIS)

    Barde, F.; Palacin, M.R.; Chabre, Y.; Isnard, O.; Tarascon, J.-M.

    2004-01-01

    The redox discharge process of the nickel oxihydroxide electrode (NOE) were followed by in situ neutron diffraction with the aim of getting a deeper insight into the phases and mechanisms involved, paying special attention to the second plateau. A set of deuterated samples was prepared to be used as a reference for the interpretation of the in situ patterns. Neutron diffraction experiments indicate that redox process is the same over both the first and second plateaus and corresponds to a phase transformation over the main part of the oxidation/reduction range and hence indicates that this phenomenon should not be associated to a structural transformation

  8. Neutron diffraction and gravimetric study of the manganese nitriding reaction under ammonia decomposition conditions.

    Science.gov (United States)

    Wood, Thomas J; Makepeace, Joshua W; David, William I F

    2018-03-28

    Manganese and its nitrides have recently been shown to co-catalyse the ammonia decomposition reaction. The nitriding reaction of manganese under ammonia decomposition conditions is studied in situ simultaneously by thermogravimetric analysis and neutron diffraction. Combining these complementary measurements has yielded information on the rate of manganese nitriding as well as the elucidation of a gamut of different manganese nitride phases. The neutron diffraction background was shown to be related to the extent of the ammonia decomposition and therefore the gas composition. From this and the sample mass, implications about the rate-limiting steps for nitriding by ammonia and nitriding by nitrogen are discussed.

  9. Analysis of neutron diffraction peak broadening caused by internal stresses in composite materials

    International Nuclear Information System (INIS)

    Todd, R.I.; Borsa, C.; Derby, B.

    1994-01-01

    Neutron diffraction is an essential tool in the study of internal stresses in composite materials. In most work only the peak shifts caused by the related elastic strains are considered, but other valuable information exists in the form of peak shape changes. The conditions under which the pure diffraction profile of the composite (i.e. the profile when all sources of broadening not caused by the residual stresses are removed) represents the probability distribution of the peak shifts corresponding to the strains are examined. It is shown that in these conditions, the pure diffraction profile has no attributes of particle size broadening (and vice versa), thereby providing a test for the validity of results interpreted in this way. The experimental derivation of measured strain distributions in Al 2 O 3 /SiCp composites using neutron diffraction is described. No apparent particle size broadening was detected, demonstrating the validity of the results, which also satisfied other tests for consistency

  10. In Situ Study of Catalytic Processes: Neutron Diffraction of a Methanol Synthesis Catalyst at Industrially Relevant Pressure

    OpenAIRE

    Kandemir, T.; Girgsdies, F.; Hansen, T.; Liss, K.; Kasatkin, I.; Kunkes, E.; Wowsnick, G.; Jacobsen, N.; Schlögl, R.; Behrens, M.

    2013-01-01

    Studying the workplace: An industrial methanol synthesis catalyst operating at high pressure was studied by in situ neutron diffraction. The peculiar microstructure of Cu/ZnO/Al2O3 nanocatalysts was found to be stable under reaction conditions. Stacking fault annealing and brass formation was only observed at temperatures higher than used in the methanol synthesis process, providing support for active role of defects in this catalyst system.

  11. Thermal transport properties, magnetic susceptibility and neutron diffraction studies of the (Cr100-xAlx)95Mo5 alloy system

    Science.gov (United States)

    Muchono, B.; Sheppard, C. J.; Venter, A. M.; Prinsloo, A. R. E.

    2018-05-01

    The Seebeck coefficient has been used to investigate QCB in Cr alloys [8,9]. Plots of d S /d T (in the limit T → 2 K) as function of concentration for the (Cr97.8Si2.2)100-yMoy [8] and the (Cr84Re16)100-zVz [9] alloy systems depicted anomalies at the QCP. The possibility of QCB in the (Cr100-xAlx)95Mo5 alloy system is explored by analysing the S(T) data of Fig. 1 by performing a linear-least-squares fit through the 2 K < T < 6.5 K data points. The gradient was taken as dS / dT|T → 2K . Fig. 8 shows dS / dT|T → 2K for concentrations in the range 0.5 ≤ x ≤ 8.6. It increases rapidly to a maximum at x = 1.0, then decreases on further Al addition and displays a minimum just above x = 1.4. This is the concentration where magnetism is seen to disappear on the TN(x) magnetic phase diagram. dS / dT|T → 2K shows a second minimum just above x = 4.4, i.e. corresponding to the concentration where magnetism reappears on the TN(x) magnetic phase diagram (see Fig. 17). Similar minima were also observed at the QCP in the (Cr84Re16)100-zVz [9] and (Cr86Ru14)100-rVr [13] alloy systems. The relatively large error bars in Fig. 8 originate from the large errors in the fitting routine due to a significant scatter in the original Seebeck coefficient data at low temperatures. The solid line through the dS / dT|T → 2K data points is a guide to the eye, while the dotted vertical lines indicate the boundaries between the ISDW, P and CSDW phases. The minima observed in the dS / dT|T → 2K curve correlate to these boundaries.

  12. Neutron diffraction study of structural transformations in ternary systems of HgSe sub 1 sub - sub x S sub x mercury chalcogenides at high pressure

    CERN Document Server

    Voronin, V I; Berger, I F; Glazkov, V P; Kozlenko, D P; Savenko, B N; Tikhomirov, S V

    2001-01-01

    The structure of the ternary systems of the HgSe sub 1 sub - sub x S sub x mercury chalcogenides is studied at high pressures up to 35 kbar. It is established that by increase in the pressure in the HgSe sub 1 sub - sub x S sub x there takes place the transition from the sphalerite type cubic structure to the cinnabar type hexagonal structure, which is accompanied by the jump-like change in the elementary cell volume and interatomic distances. The parameters of the elementary cell and positional parameters of the Hg and Se/S for the hexagonal phase of high pressure are determined. The existence of the two-phase state in the area of the phase transformation is determined

  13. Neutron Larmor diffraction with double and single precession arm

    NARCIS (Netherlands)

    van Well, A.A.; Rekveldt, M.T.

    2017-01-01

    A review is given of double and single arm Larmor diffraction. With the former a lattice-spacing resolution down to 10-6 can be obtained. The latter is a good high-resolution alternative if the sample or sample environment disturbs the magnetic field, e.g. ferromagnetic samples or applied magnetic

  14. Evidence for the Fankuchen effect in neutron diffraction by curved crystals

    International Nuclear Information System (INIS)

    Albertini, G.; Mazkedian, S.; Melone, S.; Rustichelli, F.; Boeuf, A.; Lagomarsino, S.

    1977-01-01

    Experimental evidence of the Fankuchen effect for neutron diffraction by curved crystals is presented and discussed. The Fankuchen effect consists of a space condensation of neutrons (or X-rays) diffracted by an asymmetrically cut crystal. Theoretical considerations are presented on the Fankuchen effect in the case of ideal mosaic crystals, perfect crystals and ideal curved crystals. This analysis shows that mosaic crystals behave quite differently from perfect crystals. Whereas for perfect crystals the asymmetric cut is expected to induce a real gain in neutron current density, for mosaic crystals no gain is expected. Curved crystals are expected to behave in a similar way to perfect crystals. The experiments were carried out on chemically curved Si crystals. The neutron-diffraction characteristics of a symmetrically cut Si crystal and an asymmetrically cut Si crystal were compared. A gain in the neutron current density of a factor of 4 was observed in the case of the asymmetric crystal. This value is in good agreement with the estimated theoretical value of 4.2. This fact could lead to interesting applications in the selection of monochromatic beams to be used in neutron diffractometry of small biological crystals. (Auth.)

  15. REAL STRUCTURE AND RESIDUAL STRESSES IN ADVANCED WELDS DETERMINED BY X-RAY AND NEUTRON DIFFRACTION

    Directory of Open Access Journals (Sweden)

    Karel Trojan

    2017-07-01

    Full Text Available The paper outlines the capability of X-ray diffraction (XRD for evaluation of real structure changes and residual stresses (RS on cross-section of advanced thick welds due to the welding of ferromagnetic plates. The results of neutron diffraction describe a three-dimensional state of RS and also verify previous assumptions of RS redistribution as a result of the surface preparation for determination 2D maps measured by XRD.

  16. Molecular hydrogen occupancy in binary THF-H2 clathrate hydrates by high resolution neutron diffraction.

    Science.gov (United States)

    Hester, Keith C; Strobel, Timothy A; Sloan, E Dendy; Koh, Carolyn A; Huq, Ashfia; Schultz, Arthur J

    2006-07-27

    We have determined the time-space average filling of hydrogen molecules in a binary tetrahydrofuran (THF)-d(8) + D(2) sII clathrate hydrate using high resolution neutron diffraction. The filling of hydrogen in the lattice of a THF-d(8) clathrate hydrate occurred upon pressurization. The hydrogen molecules were localized in the small dodecahedral cavities at 20 K, with nuclear density from the hydrogen approximately spherically distributed and centered in the small cavity. With a formation pressure of 70 MPa, molecular hydrogen was found to only singly occupy the sII small cavity. This result helps explain discrepancies about the hydrogen occupancy in the THF binary hydrate system.

  17. Neutron diffraction studies of U4O9: comparison with EXAFS results.

    Science.gov (United States)

    Garrido, F; Hannon, A C; Ibberson, R M; Nowicki, L; Willis, B T M

    2006-10-02

    Conradson et al. have analyzed X-ray absorption fine-structure spectra of the UO2-U4O9 system and concluded that oxygen atoms are incorporated in U4O9 as oxo groups with U-O distances in the range 1.72-1.76 A. They also found that the uranium sublattice consists of an ordered portion and an additional 'spectroscopically silent' glassy portion. We have carried out studies of powdered U4O9 by neutron diffraction which contradict these conclusions from EXAFS measurements. Our analysis shows that there are no U-O bonds shorter than 2.2 A and that U4O9 is crystallographically ordered with no evidence of a glassy structure.

  18. Neutron diffraction study of high temperature phase of K2SeO4

    International Nuclear Information System (INIS)

    Iwata, Yutaka; Koyano, Nobumitsu; Shibuya, Iwao; Hidaka, Masanori; Okazaki, Atsushi.

    1984-01-01

    The crystal structure of high-temperature phase of K 2 SeO 4 has been determined by means of single crystal neutron diffraction. The space group is P6 3 /mmc of hexagonal system with two formula units per unit cell. The structure is characterized by an averaged dispositions of SeO 4 tetrahedra with one of its Se-O bonds pointing parallel and antiparallel to the hexagonal c-axis in addition to the split distribution of potassium atoms. Heavily distorted distribution of oxygen atoms in SeO 4 is observed in Fourier maps corrersponding to split positions and reorientational motion of tetrahedra. This disordered arrangement is found to have close relation with the room temperature orthorhombic structure. The hexagonal-orthorhombic phase transition of K 2 SeO 4 at 472 0 C is grouped to an order-disorder type. (author)

  19. A Canadian perspective on engineering strain measurements by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Holden, T.M., E-mail: holdent@magma.ca [Northern Stress Technologies, Deep River, ON (Canada)

    2010-10-15

    The origins of the method, which relies on the high penetration of thermal neutrons through most industrial materials, in the late 1970s and 1980s and its development up to the present time are described. The basic steps from the measurement of lattice spacing to the calculation of stress are outlined. The length scales on which strains and stresses are manifest have a bearing on the interpretation of strain in terms of stress. A number of examples of macroscopic strain or stress fields are described where these scale considerations, as well as gradients of solute concentration that affect the interpretation of strain, matter. The strains on the length scale of the grains provide useful information about the elasticity and plasticity of materials, particularly in materials of lower symmetry than cubic. Finally, a number of future directions are suggested, which are enabled by the new intense neutron sources and improved equipment built in the last few years. (author)

  20. Neutron diffraction analysis of the microstructure of dispersion-hardening steels

    Science.gov (United States)

    Bobrikov, I. A.; Mukhametuly, B.; Balagurov, A. M.

    2016-10-01

    Neutron diffraction was employed in order to determine microdeformations in samples of stainless austenitic dispersion-hardened steels subjected to the action of high temperatures (to 700°C) during different times (up to 12 h). Experiments were conducted on a high-resolution neutron diffractometer using the timeof- flight method. The analysis performed showed systematic changes in the parameters and microdeformations of the crystal lattice. The high level of the diffractometer resolving power made it possible to reveal some important additional details of the microstructure of dispersion-hardened steels as compared to the results obtained earlier on a diffractometer with monochromatic neutron beam.

  1. Diffraction Experiments at the IBR-2 Pulsed Reactor with Methane Cold Neutron Source

    CERN Document Server

    Balagurov, A M; Mironova, G M; Pole, A V; Simkin, V G

    2000-01-01

    A new methane cold neutron source has been tested at the IBR-2 pulsed reactor at the Frank Laboratory of Neutron Physics. In a paper the results of experiments at neutron diffractometers HRFD and DN-2 which are placed at the IBR-2 from the methane moderator side are given. A comparison with the results obtained with the conventional water comb-like moderator is performed. The perspectives of the cold source for various kinds of neutron diffraction experiments, including atomic and magnetic structural analysis and real time experiments are discussed. It is shown, that for a huge number of the experiments which are performing at both HRFD and DN-2 the methane cold neutron source provides the better conditions than water comb-like moderator.

  2. Magnetic structure of the swedenborgite CaBa (Co3Fe ) O7 derived by unpolarized neutron diffraction and spherical neutron polarimetry

    Science.gov (United States)

    Qureshi, N.; Díaz, M. T. Fernández; Chapon, L. C.; Senyshyn, A.; Schweika, W.; Valldor, M.

    2018-02-01

    We present a study that combines polarized and unpolarized neutrons to derive the magnetic structure of the swedenborgite compound CaBa (Co3Fe ) O7. Integrated intensities from a standard neutron diffraction experiment and polarization matrices from spherical neutron polarimetry have been simultaneously analyzed revealing a complex order, which differs from the usual spin configurations on a kagome lattice. We find that the magnetic structure is well described by a combination of two one-dimensional representations corresponding to the magnetic superspace symmetry P 21' , and it consists of spins rotating around an axis close to the [110] direction. Due to the propagation vector q =(1/3 00 ) , this modulation has cycloidal and helicoidal character rendering this system a potential multiferroic. The resulting spin configuration can be mapped onto the classical √{3 }×√{3 } structure of a kagome lattice, and it indicates an important interplay between the kagome and the triangular layers of the crystal structure.

  3. Neutron-diffraction line broadening in a tempered martensitic steel for fusion reactors

    International Nuclear Information System (INIS)

    Coppola, R.; Lukas, P.; Mikula, P.; Vrana, M.

    1997-01-01

    The martensitic steel DIN1.4914 (MANET) belongs to the prospective materials developed for construction of future fusion reactors. The evolution of microstructure of this steel under tempering at 700 C has been investigated by neutron diffraction. The analysis of diffraction profile was used to determine some microstructural parameters, such as a mean microstrain, a mean size of coherently diffracting blocks and a dislocation density. These results are discussed in the context of different thermal treatments applied (cooling rate 150 C/min and 3600 C/min) and results of other techniques on the same set of samples. (orig.)

  4. The application of X-ray, γ-ray and neutron diffraction to the characterization of single crystal perfection

    International Nuclear Information System (INIS)

    Freund, A.; Schneider, J.R.

    1976-01-01

    The work is divided into the following three chapters: 1) diffraction by perfect and imperfect crystals, 2) experimental apparatus (describing gamma ray, X-ray and neutron diffractometers), 3) application of diffraction methods to the development of neutron monochromators. (WBU) [de

  5. Study of phase development in alumina-spodumene ceramics by high temperature neutron diffraction

    International Nuclear Information System (INIS)

    Gan, B.K.; O'Connor, B.H.

    1999-01-01

    Full text: Melting and crystallisation of minor phases are important in many material systems which contain impurities and/or grain boundary liquid phases. Grain boundary glassy phases are generally not thermodynamically stable, and can devitrify during the sintering process or from other high temperature exposure. Characterising the minor phase assemblage in these types of materials has implications in processing, microstructural design and in-service use, particularly fluctuating thermal environments. An in situ high temperature neutron diffraction (ND) technique was used to follow the phase dynamics on sintering an alumina-spodumene ceramic as well as the crystallisation kinetics of the evolving crystalline phase in real time. The main benefit of using ND analysis in the present work is that it provides bulk specimen character of the material which is important in quantitatively extracting phase composition information. Likewise, most diffraction measurements are conducted with ambient or static temperature data, collected after specimens have been heat-treated and then cooled. Such data may yield misleading information particularly in relation to non-equilibrium phases. Hence dynamic measurements are clearly preferable as a direct means of confirming sintering processes. ND measurements were performed using the High Flux Australian Reactor (HIFAR) neutron source operated by the Australian Nuclear Science and Technology Organisation (ANSTO) at Lucas Heights, NSW, Australia. The ND patterns collected on heating the compacts provided relevant information for optimising materials processing and sintering protocols. Similarly, the ND patterns collected for three specific cooling schemes yielded significant details of evolution and crystallisation of the minor phase. The principal aim was to demonstrate the fundamental influence of the minor crystalline phase (and hence glassy phase) on properties and to manipulate and tailor the phase structure by controlled

  6. In situ neutron diffraction studies of operating MGA thermal storage materials

    Directory of Open Access Journals (Sweden)

    Sugo Heber

    2017-01-01

    Full Text Available Miscibility Gap Alloys (MGA store energy as the latent heat of fusion of a discrete component within an engineered multicomponent microstructure. The thermal energy density is augmented by the associated sensible heat of the whole alloy. MGA microstructures are organised so that the low melting point component, acting as a Phase Change Material (PCM, is present as dispersed, non-intersecting particles within a continuous 3-dimensional solid matrix of a higher melting point component. The primary advantages of such an arrangement are the high thermal conductivity, 60–200 W/m K and high energy density (0.25–1.26 MJ/L. Long service life, low maintenance and the resulting simplified infrastructure offered by the ability of the MGA storage materials to exchange heat via conduction alone are further notable benefits. Unlike sensible heat storage materials, temperature measurement alone cannot indicate the state-of-charge of PCM storage since the temperature remains relatively constant throughout the melting or freezing transition. The work reported here addresses this issue through the use of in situ neutron diffraction to determine the relative volume fractions of solid (crystalline and liquid PCM within the MGA material as a function of varying temperature conditions. The aim is to provide calibration data for state-of-charge thermal models of PCM storage systems. Preliminary analysis of the neutron diffraction results and associated thermal measurements from a series of experiments carried out using the KOWARI diffractometer at the Australian Nuclear Science and Technology Organisation are presented in this work.

  7. Analytical model for neutron diffraction peak shifts due to the surface effect

    Czech Academy of Sciences Publication Activity Database

    Šaroun, Jan; Kornmeier, J. R.; Hofmann, M.; Mikula, Pavol; Vrána, Miroslav

    2013-01-01

    Roč. 46, č. 6 (2013), s. 628-638 ISSN 0021-8898 R&D Projects: GA ČR GAP204/10/0654 Institutional support: RVO:61389005 Keywords : residual-stress * neutron diffraction * Monte Carlo simulation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.950, year: 2013

  8. Residual stresses in cold-coiled helical compression springs for automotive suspensions measured by neutron diffraction

    Czech Academy of Sciences Publication Activity Database

    Matějíček, Jiří; Brand, P. C.; Drews, A. R.; Krause, A.; Lowe-Ma, C.

    2004-01-01

    Roč. 367, 1-2 (2004), s. 306-311 ISSN 0921-5093 Institutional research plan: CEZ:AV0Z2043910 Keywords : residual stress, automotive springs, neutron diffraction Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.445, year: 2004

  9. Neutron diffraction study of multipole order in light rare-earth ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 71; Issue 4. Neutron diffraction study of multipole order in light rare-earth hexaborides. J-M Mignat J ... Multipole interactions are known to play a central role in the unconventional properties of light rare-earth hexaborides and especially of CeB6. Substituting Pr at the ...

  10. Neutron diffraction study on the medium and short-range order of ternary chalcogenide glasses

    Czech Academy of Sciences Publication Activity Database

    Neov, S.; Gerasimova, I.; Skordeva, E.; Arsova, D.; Pamukchieva, V.; Mikula, Pavol; Lukáš, Petr; Sonntag, R.

    1999-01-01

    Roč. 34, - (1999), s. 3669-3676 ISSN 0022-2461 R&D Projects: GA ČR GV202/97/K038 Keywords : neutron diffraction * short-range order * chalcogenide glasses Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.786, year: 1999

  11. Neutron Diffraction Investigation of Low and High Cycle Fatigue Austenite Stainless Steels

    Czech Academy of Sciences Publication Activity Database

    Taran, Yu. V.; Schreiber, J.; Mikula, Pavol; Lukáš, Petr; Neov, Dimitar; Vrána, Miroslav

    347/349, - (2000), s. 322-327 ISSN 0255-5476 R&D Projects: GA ČR GV202/97/K038 Keywords : austenite * diffraction * fatigue * martensite * neutron * residual stress * strain Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.597, year: 2000

  12. Measurement of the velocity of sound in crystals by pulsed neutron diffraction

    International Nuclear Information System (INIS)

    Willis, B.T.M.; Carlile, C.J.; Ward, R.C.; David, W.I.F.; Johnson, M.W.

    1986-03-01

    The diffraction method of observing elementary excitations in crystals has been applied to the study of one-phonon thermal diffuse scattering from pyrolytic graphite on a high resolution pulsed neutron diffractometer. The variation of the phase velocity of sound as a function of direction in the crystal and efficient method of determining sound velocities in crystals under extreme conditions. (author)

  13. A single crystal neutron diffraction study on mixed crystal (K) 0. 25 ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 41; Issue 1. A single crystal neutron diffraction study on mixed crystal (K) 0.25 ( N H _4 ) _{0.75}H 2 PO 4 : tuning of short strong hydrogen bonds by ionic interactions. RAJUL RANJAN CHOUDHURY R CHITRA. Volume 41 Issue 1 February 2018 Article ID 8 ...

  14. Time-of-flight 3D Neutron Diffraction for Multigrain Crystallography

    DEFF Research Database (Denmark)

    Cereser, Alberto

    This thesis presents a new technique for measuring spatially resolved microstructures in crystalline materials using pulsed neutron beams. The method, called Time-of-Flight Three Dimensional Neutron Diffraction (ToF 3DND), identifies the position, shape and crystallographic orientation of the ind......This thesis presents a new technique for measuring spatially resolved microstructures in crystalline materials using pulsed neutron beams. The method, called Time-of-Flight Three Dimensional Neutron Diffraction (ToF 3DND), identifies the position, shape and crystallographic orientation...... measurements: a time resolved imaging detector, developed at University of Berkeley, California, was fitted in the interior of SENJU in order to record the extinction spots in the transmitted beam (i.e. areas with missing intensity due to Bragg diffraction of the individual grains). The arrangement of the two...... steps have been developed in this study. The work also shows that based on the transmission data alone the orientations are not uniquely determined; however, it is possible to find an unique solution by including diffraction signals from the imaging detector. The second version uses an existing method...

  15. Neutron diffraction studies of Ho1-xYxNi2B2C compounds

    DEFF Research Database (Denmark)

    Chang, L.J.; Tomy, C.V.; Paul, D.M.K.

    1996-01-01

    Neutron diffraction measurements have been carried out to investigate the nature of magnetic ordering in Ho(1-x)Y(x)Ni(2)B(2)C (x = 0, 0.1 and 0.2) compounds. HoNi(2)B(2)C shows a complex type of magnetic ordering below the superconducting transition, with a commensurate antiferromagnetic ordering...

  16. Neutron diffraction measurements of residual stress in a powder metallurgy component

    International Nuclear Information System (INIS)

    Schneider, L.C.R.; Hainsworth, S.V.; Cocks, A.C.F.; Fitzpatrick, M.E.

    2005-01-01

    Residual stresses in a typical industrial green component were determined using neutron diffraction. The measured residual stresses were found to correlate with cross-sectional variations. Residual stress at the edge of the compact in contact with the die wall during compaction reached up to +80 MPa (tension) and -100 MPa (compression)

  17. Study on thermo-mechanically controlled processing of steel using neutron diffraction

    International Nuclear Information System (INIS)

    Tomota, Yo

    2014-01-01

    Microstructure evolution during thermo-mechanically controlled processing for steels has been studied using in situ neutron diffraction. Time-sliced data on phase transformation kinetic, texture change, internal stresses, and dislocation density can be obtained for the development of advanced steels. (author)

  18. High resolution neutron diffraction study of the ionic conductor β-LiNaSO4

    International Nuclear Information System (INIS)

    Graneli, B.; Fischer, P.; Roos, J.; Brinkmann, D.; Hewat, A.W.

    1992-01-01

    A re-investigation of the structure of β-LiNaSO 4 has been made by means of high resolution neutron powder diffraction. A comparison is made with the original single crystal X-ray measurement. Implications on the conduction mechanism and possible explanations for the differences observed in a NMR investigation are discussed. (orig.)

  19. IN SITU neutron diffraction study of stresses generated by shape memory alloys

    Czech Academy of Sciences Publication Activity Database

    Šittner, Petr; Lukáš, Petr; Novák, Václav; Neov, Dimitar; Ceretti, M.

    2001-01-01

    Roč. 9, - (2001), s. 143-150 ISSN 1023-8166 R&D Projects: GA AV ČR IAA1048107; GA ČR GV202/97/K038 Institutional research plan: CEZ:AV0Z1010914 Keywords : IN SITU neutron diffraction * shape memory alloy * martensitic transformation compression - test Subject RIV: BM - Solid Matter Physics ; Magnetism

  20. Anomalous spin distribution in the superconducting ferromagnet UCoGe studied by polarized neutron diffraction

    NARCIS (Netherlands)

    Prokeš, K.; de Visser, A.; Huang, Y.K.; Fåk, B.; Ressouche, E.

    2010-01-01

    We report a polarized neutron-diffraction study conducted to reveal the nature of the weak ferromagnetic moment in the superconducting ferromagnet UCoGe. We find that the ordered moment in the normal phase in low magnetic fields (B∥c) is predominantly located at the U atom and has a magnitude of

  1. Structure of liquid caesium–bismuth alloys studied by neutron diffraction

    NARCIS (Netherlands)

    Van der Aart, S.A.; Verhoeven, V.W.J.; Verkerk, P.; Van der Lugt, W.

    2000-01-01

    Neutron diffraction experiments were carried out for two liquid alloys with compositions CsBi and Cs3Bi2. The results indicate that probably polyanions with an average number of about two Bi atoms per cluster are formed. This result contrasts with that for liquid Cs–Sb, which contains larger chains

  2. Structure of liquid caesium-bismuth alloys studied by neutron diffraction

    NARCIS (Netherlands)

    van der Aart, SA; Verhoeven, VWJ; Verkerk, P; van der Lugt, W

    2000-01-01

    Neutron diffraction experiments were carried out for two liquid alloys with compositions CsBi and Cs3Bi2. The results indicate that probably polyanions with an average number of about two Bi atoms per cluster are formed. This result contrasts with that for liquid Cs-Sb, which contains larger chains

  3. X-ray and neutron diffraction line broadening measurements in a martensitic steel for fusion technology

    International Nuclear Information System (INIS)

    Coppola, R.; Lukas, P.; Vrana, M.; Montanari, R.; Rustichelli, F.

    1995-01-01

    X-ray and neutron diffraction line broadening measurements have been carried out on a modified martensitic steel DIN 1.4914 for fusion technology (MANET) after quenching followed by tempering treatments at 700C. The results of the two experiments are discussed with reference to Cr redistribution phenomena in the matrix

  4. Neutron diffraction study of the crystallographic preferential orientation of metagabro mylonite

    Czech Academy of Sciences Publication Activity Database

    Kučeráková, M.; Vratislav, S.; Kalvoda, L.; Machek, Matěj

    2013-01-01

    Roč. 28, S2 (2013), S276-S283 ISSN 0885-7156 R&D Projects: GA ČR GA205/08/0767 Institutional support: RVO:67985530 Keywords : powder neutron diffraction * metagabro mylonite * texture analysis Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.586, year: 2013

  5. Location of Chemisorbed Methylium Ions in Zeolites by Neutron Diffraction and 13C MAS NMR

    Czech Academy of Sciences Publication Activity Database

    Vratislav, S.; Dlouhá, M.; Bosáček, Vladimír

    2002-01-01

    Roč. 74, Suppl. (2002), s. S1320-S1322 ISSN 0947-8396 R&D Projects: GA ČR GA202/00/1427 Institutional research plan: CEZ:AV0Z4040901 Keywords : zeolites * neutron diffraction * chemisorbed methyl Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.231, year: 2002

  6. Neutron Diffraction from the Second Layer of 4He on Graphite

    DEFF Research Database (Denmark)

    da Costa Carneiro, Kim; Passell, L.; Thomlinson, W.

    1981-01-01

    Neutron diffraction has been used to study the second atomic layer of **4He adsorbed on graphite. As the **4He-coverage exceeds the first layer, the second initially forms a fluid phase. But when there is enough **4He in the third layer to compress the second, this layer solidifies. The structure...

  7. Neutron diffraction studies of the magnetic structures of TbRu2Si2

    DEFF Research Database (Denmark)

    Kawano, S.; Lebech, B.; Shigeoka, T.

    2000-01-01

    We have confirmed by neutron diffraction that the high-temperature phase of TbRu2Si2 exhibits a magnetic one-dimensional modulation with Q=(3/13 0 0), while for the intermediate phase the modulation becomes two-dimensional with many satellites. At low-temperature the magnetic structure changes...

  8. Empirically testing vaterite structural models using neutron diffraction and thermal analysis.

    Science.gov (United States)

    Chakoumakos, Bryan C; Pracheil, Brenda M; Koenigs, Ryan P; Bruch, Ronald M; Feygenson, Mikhail

    2016-11-18

    Otoliths, calcium carbonate (CaCO 3 ) ear bones, are among the most commonly used age and growth structures of fishes. Most fish otoliths are comprised of the most dense CaCO 3 polymorph, aragonite. Sturgeon otoliths, in contrast, have been characterized as the rare and structurally enigmatic polymorph, vaterite-a metastable polymorph of CaCO 3 . Vaterite is an important material ranging from biomedical to personal care applications although its crystal structure is highly debated. We characterized the structure of Lake Sturgeon otoliths using thermal analysis and neutron powder diffraction, which is used non-destructively. We confirmed that while Lake Sturgeon otoliths are primarily composed of vaterite, they also contain the denser CaCO 3 polymorph, calcite. For the vaterite fraction, neutron diffraction data provide enhanced discrimination of the carbonate group compared to x-ray diffraction data, owing to the different relative neutron scattering lengths, and thus offer the opportunity to uniquely test the more than one dozen crystal structural models that have been proposed for vaterite. Of those, space group P6 5 22 model, a = 7.1443(4)Å, c = 25.350(4)Å, V = 1121.5(2)Å 3 provides the best fit to the neutron powder diffraction data, and allows for a structure refinement using rigid carbonate groups.

  9. Neutron Diffraction Studies of Dilute Cr-Re Single Crystal Alloys

    DEFF Research Database (Denmark)

    Lebech, Bente; Mikke, K.

    1972-01-01

    Neutron diffraction studies have been performed on five Cr-Re single crystal alloys with a Re content from 0 to 0·8 at. %. It was found that the wave vector of the sinusoidally modulated spin arrangement increases uniformly with temperature and concentration until a critical value of about 0·97. (2...

  10. Neutron diffraction investigation of liquid alkali metal-gallium alloys. Giant cluster formation?

    NARCIS (Netherlands)

    Alvarez, M; Lomba, E; Verkerk, P; van der Aart, SA; Bionducci, M; Mirebeau, [No Value; van der Lugt, W

    Neutron diffraction experiments were performed on the liquid alloys NaGa, NaGa3, KGa3 and CsGa3. The structure factors of KGa3 and CsGa3 display prepeaks at small wavenumbers (0.64 and 0.61 (A) over circle -1, respectively). This may indicate the existence of extremely large aggregates of atoms in

  11. Neutron diffraction study of the magnetic structure of HoCu2

    DEFF Research Database (Denmark)

    Smetana, Z.; Sima, V.; Lebech, Bente

    1986-01-01

    Neutron diffraction measurements show that in the temperature range from 7.4 to TN=10.4 K the magnetic structure of HoCu2 is a commensurably modulated a-axis collinear structure with a wave vector q1=1/3a*. Below 7.4 K an additional structure component develops and the low temperature magnetic...

  12. Neutron diffraction analysis of retained austenite stability in Mn–Si steel during plastic deformation

    Czech Academy of Sciences Publication Activity Database

    Muránsky, O.; Lukáš, Petr; Zrnik, J.; Šittner, Petr

    2006-01-01

    Roč. 385, SI-1 (2006), s. 587-589 ISSN 0378-4363 R&D Projects: GA ČR(CZ) GD202/05/H003 Institutional research plan: CEZ:AV0Z10480505; CEZ:AV0Z10100520 Keywords : neutron diffraction studies Subject RIV: BM - Solid Matter Physics ; Magnetism

  13. In situ neutron diffraction study of drawn pearlitic steel wires upon tensile deformation

    Czech Academy of Sciences Publication Activity Database

    Lukáš, Petr; Tomota, Y.; Harjo, S.; Neov, Dimitar; Strunz, Pavel; Mikula, Pavol

    2001-01-01

    Roč. 9, - (2001), s. 415-421 ISSN 1023-8166 R&D Projects: GA AV ČR IAA1048107; GA AV ČR KSK1010104 Keywords : in situ high resolution neutron diffraction * profile analysis * pearlitic steel * tensile deformation Subject RIV: BM - Solid Matter Physics ; Magnetism

  14. In situ neutron diffraction during tensile deformation of a ferrite-cementite steel

    Czech Academy of Sciences Publication Activity Database

    Tomota, Y.; Lukáš, Petr; Neov, Dimitar; Harjo, S.; Abe, YR.

    2003-01-01

    Roč. 51, č. 3 (2003), s. 805-817 ISSN 1359-6454 R&D Projects: GA ČR GA202/03/0891 Institutional research plan: CEZ:AV0Z1048901 Keywords : steel * neutron diffraction * stress-strain relationship measurement Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.059, year: 2003

  15. Neutron diffraction study of a nitrogen martensitic steel 0Kh16N4AB under load

    Czech Academy of Sciences Publication Activity Database

    Sumin, V. V.; Papushkin, I.V.; Bannykh, O.A.; Blinov, V.M.; Lukáš, Petr

    2008-01-01

    Roč. 105, č. 1 (2008), s. 88-91 ISSN 0031-918X Institutional research plan: CEZ:AV0Z10480505 Keywords : steel 0Kh16N4AB * neutron diffraction * FSD Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.412, year: 2008

  16. In Situ Neutron Diffraction Study of Drawn Pearlitic Steel Wires upon Tensile Deformation

    Czech Academy of Sciences Publication Activity Database

    Lukáš, Petr; Tomota, Y.; Harjo, S.; Neov, Dimitar; Strunz, Pavel; Mikula, Pavol

    2001-01-01

    Roč. 9, - (2001), s. 415-421 ISSN 1023-8166 R&D Projects: GA ČR GV202/97/K038 Keywords : in situ high resolution neutron diffraction * profile analysis * pearlitic steel * tensile deformation Subject RIV: BM - Solid Matter Physics ; Magnetism

  17. Recrystallization kinetics in copper investigated by in situ texture measurements by neutron diffraction

    DEFF Research Database (Denmark)

    Leffers, Torben; Hansen, Niels; Kjems, Jørgen

    1981-01-01

    The potential of neutron-diffraction texture measurement as a tool for accurate investigations of recrystallization kinetics is demonstrated by the application of the method to the recrystallization of heavily rolled copper (99.98% purity). The present investigation demonstrates that this technique...

  18. Neutron diffraction analysis of solid phases transforming in CuAlZnMn shape memory alloy

    Czech Academy of Sciences Publication Activity Database

    Neov, Dimitar; Lukáš, Petr; Černík, M.; Šittner, P.

    2001-01-01

    Roč. 2001, - (2001), s. 251-254 [Conference on applied crystallography (CAC) /18./. Katowice, 04.09.2000-07.09.2000] R&D Projects: GA AV ČR IAA1048107 Institutional research plan: CEZ:AV0Z1048901 Keywords : neutron diffraction * shape memory alloy Subject RIV: BM - Solid Matter Physics ; Magnetism

  19. In situ neutron powder diffraction and structure determination in controlled humidities.

    Science.gov (United States)

    Ting, Valeska P; Henry, Paul F; Schmidtmann, Marc; Wilson, Chick C; Weller, Mark T

    2009-12-28

    A controlled-humidity sample environment has been constructed, allowing bulk powder samples undergoing humidity-induced phase transitions and reactions to be studied via in situ neutron diffraction. Associated developments in data collection and analysis permit this to be achieved without the use of D(2)O.

  20. Textures of iron oxide ores by neutron diffraction and topotactical relation

    International Nuclear Information System (INIS)

    Wagner, F.; Esling, C.; Baro, R.; Englander, M.

    1977-01-01

    Two samples are cut from a polycrystalline haematite block. The first one is directly submitted to texture analysis by neutron diffraction, whereas the second one is first reduced into magnetite. The comparison of both textures is in agreement with a topotactical relationship previously reported for monocrystals. (orig.) [de

  1. In situ neutron diffraction measurement of stress distribution in notched tensile specimen

    International Nuclear Information System (INIS)

    Koeszegi, L.; Kocsis, M.; Zsigmond, G.; Perrin, M.

    1992-01-01

    A stress rig is constructed to make in situ neutron diffraction on tensile test specimens. The lattice spacing of the (110) reflection of a ferritic steel having nonuniform cross-section is measured both parallel and perpendicular to the applied stress. The apparent stresses are calculated. (orig.)

  2. Residual stresses determination by neutron diffraction in a 100Cr6 chromium steel bearing ring

    Czech Academy of Sciences Publication Activity Database

    Rogante, M.; Martinat, G.; Mikula, Pavol; Vrána, Miroslav

    2013-01-01

    Roč. 51, č. 5 (2013), s. 275-281 ISSN 0023-432X R&D Projects: GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : 100Cr6 steel * rings * martensitic hardening * tempering * residual stress es * neutron diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.546, year: 2013

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

    Energy Technology Data Exchange (ETDEWEB)

    Hubbard, Camden R [ORNL

    2011-09-01

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

  4. Neutron powder diffraction and high-pressure synchrotron x-ray diffraction study of tantalum nitrides

    Science.gov (United States)

    Feng, Lei-hao; Hu, Qi-wei; Lei, Li; Fang, Lei-ming; Qi, Lei; Zhang, Lei-lei; Pu, Mei-fang; Kou, Zi-li; Peng, Fang; Chen, Xi-ping; Xia, Yuan-hua; Kojima, Yohei; Ohfuji, Hiroaki; He, Duan-wei; Chen, Bo; Irifune, Tetsuo

    2018-02-01

    Not Available Project supported by the Research Foundation of Key Laboratory of Neutron Physics (Grant No. 2015BB03), the National Natural Science Foundation of China (Grant Nos. 11774247), the Science Foundation for Excellent Youth Scholars of Sichuan University (Grant No. 2015SCU04A04), and the Joint Usage/Research Center PRIUS (Ehime University, Japan) and Chinese Academy of Sciences (Grant No. 2017-BEPC-PT-000568).

  5. Neutron diffraction multiphase analysis on functional heat-resistant ceramics SiC

    International Nuclear Information System (INIS)

    Li Jizhou; Yang Jilian; Kang Jian; Ye Chuntang; Cui Hongtao

    1995-01-01

    Functional heat-resistant ceramics silicon carbide SiC is a highly feasible material for high temperature engineering applications. The SiC investigated is sintered into powder sample by using industrial SiC as semifinished materials. The neutron diffraction is performed on the powder neutron diffractometer at 15 MW heavy water research reactor of the China Institute of Atomic Energy. The least-squares crystal structure and profile refinements are undertaken with the multiphase Rietveld analysis program Fullprof, which was from ILL, Grenoble, France. The results fitted for neutron data show that besides the main phase of 2H (space group of P6 3 mc), there are 4H(C6mc), 6H(C6mc) and α-SiO 2 (Fd3m) of residual impurity. The abundance of 4 phases are 2H(73.1+-2.0)%, 4H(12.8+-1.7)%, 6H(14.0+-1.1)% and α-SiO 2 <0.1%. The result shows that neutron powder diffraction is becoming more and more powerful on materials science, while the new multiphase Rietveld profile program is used. The neutron diffraction analysis can be used not only to determine the structure of materials and but also to obtain the abundance of mixture phases

  6. Neutron diffraction study of artificial graphites crystalline anisotropy

    International Nuclear Information System (INIS)

    Lecomte, Marcel

    1961-01-01

    The Saclay spectrometer at E.L.2 has been used to investigate the structural properties of artificial graphite. Information as to the local texture at different points of a small block of graphite has been obtained. The method is more rapid and yields results which are statistically more accurate than those found by X-Ray diffraction. In particular, the method allows the determination of the degree of anisotropy in directions normal to the axis along which the block was compressed during its manufacture. (author) [fr

  7. An investigation of the structure of disordered materials by using neutron diffraction

    International Nuclear Information System (INIS)

    Petri, I.

    1999-01-01

    The structure of several semiconducting, metallic and ionic disordered materials was investigated using neutron diffraction and the results were compared with those obtained from recent ab initio molecular dynamics methods. The method of isotopic substitution was applied to measure the full set of partial structure factors, S αβ (Q), for the liquid semiconductor GeSe and the covalent network glass GeSe 2 . Their short range ordering and for GeSe 2 also the intermediate range ordering were identified and a substantial number of 'defects' such as homopolar bonds were detected in both systems. Further, the structure of liquid GeSe 2 with increasing temperature was studied at the total structure factor level. Also, changes in the topology of Ge x Se 1-x glasses in the range 0 ≤ x ≤ 0.4 were observed and investigated by measuring the total structure factors. As far as possible our results were compared with those from molecular dynamics studies. The Ge-Se system was found to serve as a sensitive test-system for these studies, giving an insight into the strengths and limitations of them. For instance, problems are found in the region of the homopolar bonds for g GeGe (r) and for the first sharp diffraction peak in the Bhatia-Thornton concentration-concentration structure factor that could not be reproduced. The structure of liquid lithium was measured and particular attention was paid to the inelasticity and resolution function corrections. The ion-ion and ion-valence electron partial structure factors were obtained and found to be in good agreement with ab initio molecular dynamics studies. The method of first order difference functions in neutron diffraction in combination with H/D substitution was applied to 2 molal solutions of Cu(ClO 4 ) 2 in perchloric acid to measure the Cu-H and, to a first order approximation, the Cu-O partial structure factor. A (4 + 1) distortion of the hydration shell around the Cu 2+ ion was measured. (author)

  8. Applications of image plates in neutron radiography and neutron diffraction at BARC, Trombay

    International Nuclear Information System (INIS)

    Shaikh, A.M.

    2013-01-01

    Neutron radiography techniques based on Gd, Dy and In metallic foils and X-ray film have been used at this centre since early seventies for various NDT and R and D work in nuclear, defence and aerospace industries. In recent years use of photostimulated luminescence based phosphor imaging plate has been introduced in our work. This has enabled to achieve higher sensitivities and dynamic ranges of recording radiographs with acceptable spatial resolution. It also provides digital image information which is more convenient for quantitative evaluations. Neutron image plates have been used in variety of radiography techniques such as conventional neutron radiography (NR), neutron induced beta radiography (NIBR), hydrogen sensitive epithermal neutron radiography (HYSEN) and for neutron powder diffractometry using Apsara, CIRUS and Dhruva reactors as neutron sources. Recently the image plates have also been used for characterization of thermalized neutron beam from a plasma focus neutron source and recording neutron radiographs. Prior to the utilization image plates have been characterised for their performance. Details of the measurements and applications will be presented. (author)

  9. Rietveld refinement with time-of-flight powder diffraction data from pulsed neutron sources

    International Nuclear Information System (INIS)

    David, W.I.F.; Jorgensen, J.D.

    1990-10-01

    The recent development of accelerator-based pulsed neutron sources has led to the widespread use of the time-of-flight technique for neutron powder diffraction. The properties of the pulsed source make possible unusually high resolution over a wide range of d spacings, high count rates, and the ability to collect complete data at fixed scattering angles. The peak shape and other instrument characteristics can be accurately modelled, which make Rietveld refinement possible for complex structures. In this paper we briefly review the development of the Rietveld method for time-of-flight diffraction data from pulsed neutron sources and discuss the latest developments in high resolution instrumentation and advanced Rietveld analysis methods. 50 refs., 12 figs., 14 tabs

  10. New developments of TOF neutron diffraction at the IBR-2 pulsed reactor

    International Nuclear Information System (INIS)

    Balagurov, Anatoli M.

    2001-01-01

    Development of high-resolution RTOF Fourier technique for powder neutron diffraction studies is being continued at the IBR-2 pulsed reactor in Dubna. Besides some technical improvements in the operating HRFD instrument, a new dedicated instrument, Fourier Strain Diffractometer (FSD), for investigation of residual stresses in bulk materials has been constructed at IBR-2 in 1999. With a new HRFD Fourier chopper smaller than 10 μs TOF contribution in a resolution function was obtained in the experiment with perfect Si single crystal. A series of diffraction experiments with the beams from a new methane cold neutron moderator installed at the IBR-2 in 1999 is discussed. A comparison with the results obtained with the conventional water comb-like moderator shows that for various types of experiments, which are performed at HRFD and DN-2 diffractometers, the methane cold neutron source provides better conditions. (author)

  11. Neutron diffraction investigation of an in-plane biaxial fatigued stainless steel sample of cruciform geometry

    Science.gov (United States)

    Taran, Yu V.; Balagurov, A. M.; Sheverev, S. G.; Schreiber, J.; Korsunsky, A. M.; Vorster, W. J. J.; Bomas, H.; Stoeberl, C.

    2008-03-01

    Fatigue and fracture under multiaxial stresses are among the most important current research topics aimed at ensuring improved reliability of industrial components. An ex situ in-plane biaxial low cycle fatigued sample of cruciform geometry from austenitic stainless steel AISI 321 H was investigated on the FSD stress-diffractometer at the IBR-2 pulsed nuclear reactor by using the neutron strain scanner and the uniaxial stress rig. The phase composition of fatigued material was determined and the residual macrostresses and phase microstresses were measured. To the best of our knowledge, no neutron diffraction investigations of materials subjected to biaxial loading have been previously carried out. The first results of the neutron diffraction experiment are presented and discussed.

  12. Protein crystallization and initial neutron diffraction studies of the photosystem II subunit PsbO.

    Science.gov (United States)

    Bommer, Martin; Coates, Leighton; Dau, Holger; Zouni, Athina; Dobbek, Holger

    2017-09-01

    The PsbO protein of photosystem II stabilizes the active-site manganese cluster and is thought to act as a proton antenna. To enable neutron diffraction studies, crystals of the β-barrel core of PsbO were grown in capillaries. The crystals were optimized by screening additives in a counter-diffusion setup in which the protein and reservoir solutions were separated by a 1% agarose plug. Crystals were cross-linked with glutaraldehyde. Initial neutron diffraction data were collected from a 0.25 mm 3 crystal at room temperature using the MaNDi single-crystal diffractometer at the Spallation Neutron Source, Oak Ridge National Laboratory.

  13. Neutron-diffraction studies of a Cr+0.88 at. % Ga alloy

    CERN Document Server

    Venter, A M; Alberts, H L

    2002-01-01

    A neutron-diffraction study has been performed on a Cr-Ga alloy single crystal containing 0.88 at. % Ga. Well-defined anomalies were observed in the integrated neutron intensities at the spin-flip as well as at the incommensurate-commensurate spin-density-wave magnetic phase-transition temperatures T sub s sub f and T sub I sub C , respectively. Unusually strong spin-fluctuation effects persist in the crystal to temperatures well above the Neel point. The neutron-diffraction results enhance previous arguments to solve a reported discrepancy between the calculated and directly measured signs of the pressure derivative of T sub I sub C. (orig.)

  14. Neutron diffraction investigation of an in-plane biaxial fatigued stainless steel sample of cruciform geometry

    International Nuclear Information System (INIS)

    Taran, Yu V; Balagurov, A M; Sheverev, S G; Schreiber, J; Korsunsky, A M; Vorster, W J J; Bomas, H; Stoeberl, C

    2008-01-01

    Fatigue and fracture under multiaxial stresses are among the most important current research topics aimed at ensuring improved reliability of industrial components. An ex situ in-plane biaxial low cycle fatigued sample of cruciform geometry from austenitic stainless steel AISI 321 H was investigated on the FSD stress-diffractometer at the IBR-2 pulsed nuclear reactor by using the neutron strain scanner and the uniaxial stress rig. The phase composition of fatigued material was determined and the residual macrostresses and phase microstresses were measured. To the best of our knowledge, no neutron diffraction investigations of materials subjected to biaxial loading have been previously carried out. The first results of the neutron diffraction experiment are presented and discussed

  15. Optimization of spring exchange coupled ferrites, studied by in situ neutron diffraction

    DEFF Research Database (Denmark)

    Ahlburg, Jakob; Christensen, Mogens; Granados-Miralles, Cecilia

    ) is reduced to a metallic alloy CoFe (soft magnet) by heating the sample and flowing it with hydrogen gas. It is studied in situ using neutron powder diffraction with a time resolution of 12 min. The transition from spinel to pure metal goes through an intermediate step of a metal oxide before being fully...... reduced. These metal oxides are antiferromagnetically ordered an is therefore considered a parasitic phase. However by fine-tuning the reaction temperature and hydrogen flow rate the occurrence of the phase can be minimized. In order to distinguish between Co and Fe Neutrons are chosen. Since neutrons...... have a spin it will also be possible to measure a magnetic signal and investigate the exchange-coupling. After the reduction the samples was furthermore investigated using powder x-ray diffraction and VSM (vibrating sample magnetometer). To understand the reaction mechanism, a series of experiments...

  16. Neutron diffraction and gravimetric study of the iron nitriding reaction under ammonia decomposition conditions.

    Science.gov (United States)

    Wood, Thomas J; Makepeace, Joshua W; David, William I F

    2017-10-18

    Ammonia decomposition over iron catalysts is known to be affected by whether the iron exists in elemental form or as a nitride. In situ neutron diffraction studies with simultaneous gravimetric analysis were performed on the nitriding and denitriding reactions of iron under ammonia decomposition conditions. The gravimetric analysis agrees well with the Rietveld analysis of the neutron diffraction data, both of which confirm that the form of the iron catalyst is strongly dependent on ammonia decomposition conditions. Use of ammonia with natural isotopic abundance as the nitriding agent means that the incoherent neutron scattering of any hydrogen within the gases present is able to be correlated to how much ammonia had decomposed. This novel analysis reveals that the nitriding of the iron occurred at exactly the same temperature as ammonia decomposition started. The iron nitriding and denitriding reactions are shown to be related to steps that take place during ammonia decomposition and the optimum conditions for ammonia decomposition over iron catalysts are discussed.

  17. Residual stress measurement of the jacket material for ITER coil by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, Yoshinori [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    Nickel-Iron based super alloy INCOLOY 908 is used for the jacket of a central solenoid coil (CS coil) of the International Thermonuclear Experimental Reactor (ITER). INCOLOY 908, however, has a possibility of fracture due to Stress Accelerated Grain Boundary Oxidation (SAGBO) under a tensile residual stress beyond 200MPa. Therefore it is necessary to measure the residual stress of the jacket to avoid SAGBO. We performed residual stress measurement of the jacket by neutron diffraction using the neutron diffractometer for residual stress analysis (RESA) installed at JRR-3M in JAERI. A sample depth dependence of internal strain was obtained from the (111) plane spacing. A residual stress distribution was calculated from the strain using Young`s modulus and Poisson`s ratio that were evaluated by a tensile test with neutron diffraction. The result shows that the tensile residual stress exceeds 200MPa of the SAGBO condition in some regions inside the jacket. (author)

  18. Uranium and thorium hydride complexes as multielectron reductants: a combined neutron diffraction and quantum chemical study.

    Science.gov (United States)

    Grant, Daniel J; Stewart, Timothy J; Bau, Robert; Miller, Kevin A; Mason, Sax A; Gutmann, Matthias; McIntyre, Garry J; Gagliardi, Laura; Evans, William J

    2012-03-19

    The unusual uranium reaction system in which uranium(4+) and uranium(3+) hydrides interconvert by formal bimetallic reductive elimination and oxidative addition reactions, [(C(5)Me(5))(2)UH(2)](2) (1) ⇌ [(C(5)Me(5))(2)UH](2) (2) + H(2), was studied by employing multiconfigurational quantum chemical and density functional theory methods. 1 can act as a formal four-electron reductant, releasing H(2) gas as the byproduct of four H(2)/H(-) redox couples. The calculated structures for both reactants and products are in good agreement with the X-ray diffraction data on 2 and 1 and the neutron diffraction data on 1 obtained under H(2) pressure as part of this study. The interconversion of the uranium(4+) and uranium(3+) hydride species was calculated to be near thermoneutral (~-2 kcal/mol). Comparison with the unknown thorium analogue, [(C(5)Me(5))(2)ThH](2), shows that the thorium(4+) to thorium(3+) hydride interconversion reaction is endothermic by 26 kcal/mol. © 2012 American Chemical Society

  19. Crystal structure investigations on cation-substituted alums by X-ray and neutron diffraction

    International Nuclear Information System (INIS)

    Abdeen, A.M.

    1980-04-01

    The crystal structures of the three alums: NH 4 Al(SO 4 ) 2 .12H 2 O, (NH 3 CH 3 )Al(SO 4 ) 2 .12H 2 O and (NH 3 OH)Al(SO 4 ) 2 .12H 2 O have been determined from three-dimensional neutron diffraction data enhanced by X-ray diffraction when necessary. These compounds crystallize cubic in space group Pa3. The structures of the three alums exhibit partial occupancies of crystallographic sites for the NH 4 , (NH 3 CH 3 ) and (NH 3 OH) group atoms. This can be explained by a quantized rotation of the three groups around an axis perpendicular to the [111] direction. Some of the (SO 4 ) 2- groups in the NH 4 -alum are disordered with about 17% of the sulfate tetrahedra being in a reversed orientation around the sulfur atom. The disorder in (NH 3 CH 3 ) and (NH 3 OH)-alums is only 4,3% and 3.0% respectively. The atoms in the alum structures are held together by a system of hydrogen bonds between the water molecules and between the water molecules and the sulfate oxygen atoms. In these three structures there is a strong indication that shorter hydrogen bonds tend to be nearly linear. (orig.)

  20. Hierarchical characterization by EBSD and neutron diffraction on heterogeneous deformation behavior of a martensitic steel

    International Nuclear Information System (INIS)

    Morooka, Satoshi; Tomota, Yo; Adachi, Yoshitaka; Morito, Shigekazu; Kamiyama, Takashi

    2008-01-01

    A novel combined technique of neutron diffraction and electron back scattering diffraction was applied to examine hierarchical deformation behavior of 18 mass% Ni martensitic steel. In-situ neutron diffraction experiment during tensile deformation demonstrated that intergranular stress was generated. EBSD analysis suggested that slip bands terminated not only at block boundaries, but also sub-block boundaries at a relatively small strain. In many cases, slip bands crossing sub-block boundaries were zigzagged. With increasing strain, sub-block became unclear and then block boundaries worked as a main barrier for dislocation gliding. Such kind of heterogeneous plastic flow in differently oriented hkl blocks seems to be a possible reason for the intergranular stresses. (author)

  1. NXDC-neutron and x-ray diffraction code for crystal structures calculations

    International Nuclear Information System (INIS)

    Abbas, Y.; El-Sherif, A.

    1982-01-01

    A computer program NXDC for the calculations of neutron diffraction and x-ray diffraction intensities is reported. The program is very flexible and allows the intensity of a reflection with a given Miller indices to be calculated if the unit cell and its contents are specified together with the equipement used Neutrons or X-rays-and if necessary introducing temperature and absorption factors corrections. For the refinement of crystal structures provision is made for the comparison of the calculated intensities and the intergrated intensities observed from the diffraction diagrams using the least-squares analysis to obtain the reliability factor R. The program is written in FORTRAN Iv and is very suitable for minicomputers

  2. Time-of-Flight Three Dimensional Neutron Diffraction in Transmission Mode for Mapping Crystal Grain Structures

    DEFF Research Database (Denmark)

    Cereser, Alberto; Strobl, Markus; Hall, Stephen A.

    2017-01-01

    constituting the material. This article presents a new non-destructive 3D technique to study centimeter-sized bulk samples with a spatial resolution of hundred micrometers: time-of-flight three-dimensional neutron diffraction (ToF 3DND). Compared to existing analogous X-ray diffraction techniques, ToF 3DND......-of-flight neutron beamline. The technique was developed and tested with data collected at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Complex (J-PARC) for an iron sample. We successfully reconstructed the shape of 108 grains and developed an indexing procedure....... The reconstruction algorithms have been validated by reconstructing two stacked Co-Ni-Ga single crystals, and by comparison with a grain map obtained by post-mortem electron backscatter diffraction (EBSD)....

  3. Study of the ferrimagnetic and paramagnetic phases of magnetite measured by multiple neutron diffraction

    International Nuclear Information System (INIS)

    Mazzocchi, V.L.

    1992-01-01

    Structural parameters of the ferrimagnetic and paramagnetic phases of magnetite have been refined from neutron multiple diffraction data. Experimental multiple diffraction patterns used in the refinement, were obtained by measuring the 111 primary reflection of a natural single crystal of this compound, at room temperature for the ferrimagnetic phase and 703 0 C for the paramagnetic phase. Corresponding theoretical patterns for both phases have been calculated by the program MULTI which uses the iterative method for the intensity calculations in neutron multiple diffraction. In this method intensities are calculated as Taylor series expansions summed up to a order sufficient for a good approximation. A step by step process has been used in the refinements according to the parameter-shift method. Both isotropic and anisotropic thermal parameters were used in the calculation of the temperature factor. (author)

  4. Analysis of the retained austenite stability in TRIP steels by X-ray and neutron diffraction

    International Nuclear Information System (INIS)

    Son, Dong Min; Choi, Il Dong; Shin, Eun Joo

    2005-01-01

    The energy absorption of an automotive sheet steel during crash, that is, at a high speed deformation is very important to the safety of passengers. Therefore, property data and deformation mechanisms of materials under high strain rate conditions are needed to choose proper materials for automobiles. Dynamic mechanical properties of low carbon TRIP steels with varying retained austenite stabilities were evaluated over a wide range of strain rates using a high-velocity hydraulic tensile testing machine. The effect of retained austenite stability on high speed deformation behavior can be evaluated by the proper estimation of transformation in retained austenite. The quantity of transformed retained austenite after deformation was analyzed by X-ray diffraction and high resolution neutron diffraction and compared the results from two test methods. The carbon in retained austenite was analyzed by neutron diffraction. High stability retained austenite has higher carbon content than low stability retained austenite and transformed slowly

  5. Effect of wavelength-dependent attenuation on strain measurement using pulsed neutron diffraction

    International Nuclear Information System (INIS)

    Wang, D.-Q.; Santisteban, J.R.; Edwards, L.

    2001-01-01

    The measurement of stresses in engineering components and structures by neutron diffraction has traditionally been limited to depths of a few centimetres. However, recent developments in instrumentation open up the possibility of deeper measurements. It has been suggested that a systematic error may occur when measuring stresses deep in materials due to wavelength-dependent attenuation of the incident and/or diffracted beam. A series of experiments to evaluate the magnitude of this effect on ENGIN, a pulsed neutron strain scanner will be presented in this paper. It was found that the pseudo-strains induced by the attenuation of the diffracted beam were negligible, whereas there was a small but still noticeable effect produced by the attenuation in the incident beam. The possible causes of this shift and the consequences for deep measurements are discussed

  6. Effect of wavelength-dependent attenuation on strain measurement using pulsed neutron diffraction

    CERN Document Server

    Wang, D Q; Edwards, L

    2001-01-01

    The measurement of stresses in engineering components and structures by neutron diffraction has traditionally been limited to depths of a few centimetres. However, recent developments in instrumentation open up the possibility of deeper measurements. It has been suggested that a systematic error may occur when measuring stresses deep in materials due to wavelength-dependent attenuation of the incident and/or diffracted beam. A series of experiments to evaluate the magnitude of this effect on ENGIN, a pulsed neutron strain scanner will be presented in this paper. It was found that the pseudo-strains induced by the attenuation of the diffracted beam were negligible, whereas there was a small but still noticeable effect produced by the attenuation in the incident beam. The possible causes of this shift and the consequences for deep measurements are discussed.

  7. Elastoplastic properties of duplex steel determined using neutron diffraction and self-consistent model

    International Nuclear Information System (INIS)

    Baczmanski, A.; Braham, C.

    2004-01-01

    A new method for determining the parameters characterising elastoplastic deformation of two-phase material is proposed. The method is based on the results of neutron diffraction and mechanical experiments, which are analysed using the self-consistent rate-independent model of elastoplastic deformation. The neutron diffraction method has been applied to determine the lattice strains and diffraction peak broadening in two-phase austeno-ferritic steel during uniaxial tensile test. The elastoplastic model was used to predict evolution of internal stresses and critical resolved shear stresses. Calculations based on this model were successfully compared with experimental results and the parameters characterising elastoplastic deformation were determined for both phases of duplex steel

  8. Procedures for interface residual stress determination using neutron diffraction: Mo-coated steel gear wheel

    International Nuclear Information System (INIS)

    Bruno, Giovanni; Fanara, Carlo; Hughes, Darren J.; Ratel, Nicolas

    2006-01-01

    Residual stresses were determined in steel gear wheels coated with molybdenum using neutron diffraction. A systematic procedure was developed to assess them in both the molybdenum coating and in the steel substrate. A detailed description of the problems associated with measurements of this type is given, together with a procedure aimed at rationalising their solution. Precise sample positioning was developed using a new experimental method and advanced metrology equipment allowing off-line sample alignment and mounting. This reliably replaces the inefficient use of entrance scans, usually adopted in residual stress analysis by neutron diffraction. Corrections were applied to overcome the presence of pseudo-strains and data reduction was performed to coherently interpret the results, including the determination of the centre-of-mass of the diffracting volume. The full three-dimensional stress profile was determined in the coating and the substrate. The data analysis methodology is fully described and recommendations are given for this kind of measurement

  9. Measurement of residual stress in textured Al alloy by neutron diffraction method

    International Nuclear Information System (INIS)

    Okido, S.; Hayashi, M.; Tanaka, K.; Akiniwa, Y.; Minakawa, N.; Morii, Y.

    1999-01-01

    Residual stress generated in a shrunken aluminum alloy specimen, which was prepared for the round robin test conducted by VAMAS (Versailles Project on Advanced Materials and Standards) TWA-20 organized for the purpose of standardizing residual stress measurement methods, was evaluated by a neutron diffraction method. The main purpose of the round robin test was to assess the reproducibility of data obtained with the measurement facilities of the participants. The general standard of the Residual Stress Analyzer (RESA) constructed in the Japan Atomic Energy Research Institute was verified from the measured residual strains, which were equivalent to the values calculated by FEM and values measured by the research facilities in North America. Residual stress was calculated from residual strain in three perpendicular directions. The diffraction intensities were dependent on measurement directions since the prepared specimen possessed texture. Diffraction profiles in directions having a weak diffraction intensity caused an inaccurate evaluation of the residual stress. To solve this problem, a new method for evaluating residual stress with respect to diffraction plane dependency of the elastic constant was applied. The diffraction plane giving the highest intensity among 110, 200, and 220 diffraction was used to evaluate the residual strain in each of three directions. The residual strain obtained on the used diffraction plane was converted to the equivalent strain for the defined diffraction plane using the ratio of elastic constants of these two planes. The developed evaluation method achieved highly accurate measurement and remarkable efficiency in the measurement process. (author)

  10. Structural studies of WO3-TeO2 glasses by high-Q-neutron diffraction and Raman spectroscopy

    International Nuclear Information System (INIS)

    Khanna, A.; Kaur, A.; Krishna, P.S.R.; Shinde, A.B.

    2013-01-01

    Glasses from the system: xWO 3 -(100-x)TeO 2 (x=15, 20 and 25 mol %) were prepared by melt quenching technique and characterized by density, UV-visible absorption spectroscopy, Differential Scanning Calorimetry (DSC), Raman spectroscopy and high-Q neutron diffraction measurements. Glass density and glass transition temperature increased with increase in WO 3 concentration, Raman spectroscopy indicated the conversion of TeO 4 units into TeO 3 units with increase in WO 3 content. The increase in glass transition temperature with the incorporation of WO 3 was attributed to the increase in average bond strength of the glass network since the bond dissociation energy of W-O bonds (672 kJ/mol) is significantly higher than that of Te-O bonds (376 kJ/mol). UV-visible studies found a very strong optical absorption band due to W 6+ ions, just below the absorption edge. High-Q neutron diffraction measurements were performed on glasses and radial distribution function analyses revealed changes in W-O and Te-O correlations in the glass network. The findings about changes in glass structure from neutron diffraction studies were consistent with structural information obtained from Raman spectroscopy and structure-property correlations were made. (author)

  11. An In Situ Study of Sintering Behavior and Phase Transformation Kinetics in NiTi Using Neutron Diffraction

    Science.gov (United States)

    Chen, Gang; Liss, Klaus-Dieter; Cao, Peng

    2015-12-01

    The powder sintering behavior of NiTi from an elemental powder mixture of Ni/Ti has been investigated, using an in situ neutron diffraction technique. In the sintered alloys, the overall porosity ranges from 9.2 to 15.6 pct, while the open-to-overall porosity ratio is between 8.3 and 63.7 pct and largely depends on the sintering temperature. In comparison to powder compacts sintered at 1223 K and 1373 K (950 °C and 1100 °C), the powder compact sintered at 1153 K (880 °C) shows a much smaller pore size, a higher open-to-overall porosity ratio but smaller shrinkage and a lower density. Direct evidence of eutectoid transformation in the binary Ni-Ti system during furnace cooling to ca. 890 K (617 °C) is provided by in situ neutron diffraction. The intensities of the B2-NiTi reflections decrease during the holding stage at 1373 K (1100 °C), which has been elaborated as an extinction effect according to the dynamical theory of neutron diffraction, when distorted crystallites gradually recover to perfect crystals. The analysis on the first five reflections clarifies the non-existence of any order-disorder transition in the NiTi phase from B2-to-BCC structure.

  12. In-situ neutron diffraction measurements of temperature and stresses during friction stir welding of 6061-T6 aluminum alloy

    International Nuclear Information System (INIS)

    Woo, Wan Chuck; Feng, Zhili; Wang, Xun-Li; Brown, D.W.; Clausen, B.; An, Ke; Choo, Hahn; Hubbard, Camden R.; David, Stan A.

    2007-01-01

    The evolution of temperature and thermal stresses during friction stir welding of Al6061-T6 was investigated by means of in-situ, time-resolved neutron diffraction technique. A method is developed to deconvolute the temperature and stress from the lattice spacing changes measured by neutron diffraction. The deep penetration capability of neutrons made it possible for the first time to obtain the temperature and thermal stresses inside a friction stir weld

  13. High-temperature neutron diffraction study of modified KNbO3

    International Nuclear Information System (INIS)

    Jauhari, Mrinal; Mishra, S.K.; Mittal, R.; Krishna, P.S.R.; Chaplot, S.L.

    2016-01-01

    Potassium niobate (KNbO 3 ) and its derivatives are suitable candidates of lead-free and an environmental friendly piezoelectric material. The solid solution of Potassium niobate and Bismuth ferrite ((0.9KNbO 3 -0.1BiFeO 3 : KB 10 ) was prepared by solid state reaction method. The high-temperature powder neutron diffraction technique has been used to identify the structural phase transitions in this compound. Left side panel shows the experimental neutron diffraction patterns of the KB 10 at selected temperatures. We observed interesting changes in the neutron diffraction patterns with the change in temperature,as revealed by change in the Braggs profile. Neutron diffraction peaks are shifted to lower angle side with increasing temperature and showing the positive thermal expansion. The strongest changes in the diffraction patterns occur around ∼ 62° at 450K and 675K, provides evidence for structural phase transitions at these temperatures. Detailed Rietveld refinement analysis of the powder diffraction data suggest structural phase transition from ferroelectric the orthorhombic (Amm2) to ferroelectric tetragonal (P4mm) around 450K and finally transform to paraelectric cubic (Pm-3m) phase around 675K. Right side panel depicts the evolution of lattice parameter with temperature for KB10. There are three regions depicted corresponding to orthorhombic, tetragonal and cubic phase of the compound. It is evident that the a P lattice parameter of orthorhombic phase increases with increasing temperature in the entire temperature range. On the other hand, the b P and c P lattice parameters in both orthorhombic and tetragonal phase, first increase and then decrease with increasing temperature

  14. High-resolution neutron powder-diffraction in CMR manganates

    Energy Technology Data Exchange (ETDEWEB)

    Suard, E.; Radaelli, P.G. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)

    1997-04-01

    Manganese-oxide materials have recently been the subject of renewed attention, due to the `colossal` magnetoresistance (CMR) displayed near the spin-ordering temperature T{sub c} by some of these compounds. CMR has been evidenced in at least three families of manganese oxides. In most cases, the CMR compounds behave as paramagnetic semiconductors at high temperatures, and as ferromagnetic metals below T{sub c}. The study of this metallization process has lead some theorists to challenge its traditional interpretation in terms of the so-called double-exchange mechanism, and to propose alternative scenarios in which the coupling of the charge carriers with the lattice plays a paramount role. Powder diffraction method, being at the forefront of CMR research is presented. (author). 4 refs.

  15. Evaluation of residual stresses in metal matrix composite materials, by the means of neutron and X-ray diffraction

    International Nuclear Information System (INIS)

    Ceretti, M.; Braham, C.

    1996-01-01

    Thermally- as well as mechanically-induced residual stresses in metal matrix composites have been analyzed by the means of two complementary techniques: X-ray diffraction for surface analysis, and neutron diffraction for volume analysis. The residual stress relaxation is examined through in-situ measurements with neutron diffraction. Results from both techniques are well correlated, on condition that the same basic assumptions are used

  16. Complicated systems for neutron detection

    International Nuclear Information System (INIS)

    Kozlov, I.M.; Nikotin, O.P.; Chekrenev, A.S.

    1982-01-01

    The design of the system for detecting delayed neutrons due to heavy nuclei photofission is described. The system comprises a large number of 3 He proportional counters of thermal neutrons. Each counter is equipped with an individual amplifier, discriminator and pUlse shaper. The tuning of a detector comprising several counters has been realized by changing the discrimination voltage in such a manner that the point of the ν radiation initial counting for all counters is under the same voltage of the high voltage source. Such method permits not only to reduce the tuning time but to obtain also an optimum value of perfect separation of signals from neutrons and ν radiation. Data processing has been performed by the commutator which permits to add signals in different versions. The choice of the version has been determined by output control potentials. The commutator functions have been recorded in the symbols of algebra logics. The described detector with the commutator has been employed in kinetic measurements of photofission delayed neutrons, for detecting fission neutrons with neutron background, from (α, n) for measuring the distribution of a number of instantaneous neutrons per fission act. The above principles of the detectors structure and data processing and recording facilities permit to unite according power supplies any number of thermal neutron counters and apply more complicated circuats of counter signal commutators

  17. Through-Thickness Measurements of Residual Stresses in an Overlay Dissimilar Weld Pipe using Neutron Diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Wan Chuck; EM, Vyacheslav; Lee, Ho Jin; Kim, Kang Soo; Kang, Mi Hyun; Joo, Jong Dae; Seong, Baek Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Byeon, Jin Gwi; Park, Kwang Soo [Doosan Heavy Industries and Construction Co., Changwon (Korea, Republic of)

    2010-10-15

    The distribution of residual stresses in dissimilar material joints has been extensively studied because of the wide applications of the dissimilar welds in many inevitable complex design structures. Especially the cracking of dissimilar welding has been a long standing issue of importance in many components of the power generation industries such as nuclear power plant, boiling pressure system, and steam generators. In particular, several failure analysis and direct observations have shown that critical fractures have frequently occurred in one side of the dissimilar welded parts. For example, the heat-affected zone on the ferrite steel side is known to critical in many dissimilar welding pipes when ferrite (low carbon steel) and austenite (stainless) steels are joined. The main cause of the residual stresses can be attributed to the mismatch in the coefficient of thermal expansion between the dissimilar metals (ferrite and austenite). Additional cladding over circumferential welds is known to reinforce the mechanical property due to the beneficial compressive residual stress imposed on the weld and heat-affected zone. However, science-based quantitative measurement of the through thickness residual stress distribution is very limited in literature. The deep penetration capability of neutrons into most metallic materials makes neutron diffraction a powerful tool to investigate and map the residual stresses of materials throughout the thickness and across the weld. Furthermore, the unique volume averaged bulk characteristic of materials and mapping capability in three dimensions are suitable for the engineering purpose. Thus, the neutron-diffraction measurement method has been selected as the most useful method for the study of the residual stresses in various dissimilar metal welded structures. The purpose of this study is to measure the distribution of the residual stresses in a complex dissimilar joining with overlay in the weld pipe. Specifically, we measured

  18. Status and recent developments in diffractive neutron optics at the ILL

    Science.gov (United States)

    Courtois, P.; Bigault, T.; Andersen, K. H.; Baudin-Cavallo, J.; Ben Saïdane, K.; Berneron, M.; El-Aazzouzzi, A.; Gorny, D.; Graf, W.; Guiblain, T.; Hehn, R.; Hetzler, E.; Menthonnex, C.; Mestrallet, B.; Dewhurst, C.

    2006-11-01

    We present the present status and recent advances in diffractive neutron optics at the ILL. Very high-quality copper crystals with intrinsic mosaics of the order of 1‧ can now be produced which is of interest for the reproducible production of higher-mosaic anisotropic crystals for neutron monochromators and potentially for a gamma-ray Laue lens for astrophysical applications. Recent progress in the growth of mosaic germanium crystals now allows us to produce high-quality crystals with a controllable and anisotropic mosaic of up to several degrees. Polarising supermirrors of Fe-Si can now be produced with critical angles of up to 4 times the critical angle of natural nickel. Recent applications include a solid-state S-bender, a transmission polariser for small-angle scattering and a polarising monochromator for 8.9 Å neutrons for the production of ultra-cold neutrons.

  19. Status and recent developments in diffractive neutron optics at the ILL

    International Nuclear Information System (INIS)

    Courtois, P.; Bigault, T.; Andersen, K.H.; Baudin-Cavallo, J.; Ben Saidane, K.; Berneron, M.; El-Aazzouzzi, A.; Gorny, D.; Graf, W.; Guiblain, T.; Hehn, R.; Hetzler, E.; Menthonnex, C.; Mestrallet, B.; Dewhurst, C.

    2006-01-01

    We present the present status and recent advances in diffractive neutron optics at the ILL. Very high-quality copper crystals with intrinsic mosaics of the order of 1' can now be produced which is of interest for the reproducible production of higher-mosaic anisotropic crystals for neutron monochromators and potentially for a gamma-ray Laue lens for astrophysical applications. Recent progress in the growth of mosaic germanium crystals now allows us to produce high-quality crystals with a controllable and anisotropic mosaic of up to several degrees. Polarising supermirrors of Fe-Si can now be produced with critical angles of up to 4 times the critical angle of natural nickel. Recent applications include a solid-state S-bender, a transmission polariser for small-angle scattering and a polarising monochromator for 8.9 A neutrons for the production of ultra-cold neutrons

  20. Neutron diffraction on a moving grating and quasi-energy of cold neutrons

    International Nuclear Information System (INIS)

    Frank, A.I.; Nosov, V.G.

    1994-01-01

    A solution is found to the problem of the motion of an absorbing or phase grating across a monochromatic neutron beam. It is found that a very close connection exists between this problem and the problem of fast periodic chopping of a neutron beam. (orig.)