Journal articles: 'Neutron diffraction technique'

1

Feldmann, K. "Texture Investigations by Neutron Time-of-Flight Diffraction." Textures and Microstructures 10, no. 4 (January 1, 1989): 309–23. http://dx.doi.org/10.1155/tsm.10.309.

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For the majority of isotopes the thermal neutron absorption cross section is two or more orders lower than that for X-rays. This makes neutron diffraction well-suited for bulk texture investigations. Some characteristics of neutron diffraction are discussed. The principles of neutron time-of-flight diffraction are described. The pole figure determination by means of TOF technique is considered. The main parameters of the present Dubna texture facility are given. Further developments of the experimental technique are considered. The application of the TOF technique for inverse pole figure measurement is discussed as an approach to direct observation of the texture forming process. The magnetic moments of neutrons can be used to study magnetic textures. Two different techniques are discussed.

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Jorgensen, James D., and John M. Newsam. "Neutron Powder Diffraction." MRS Bulletin 15, no. 11 (November 1990): 49–55. http://dx.doi.org/10.1557/s088376940005836x.

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For many classes of materials, neutron diffraction is the best way to obtain detailed atomic-level structural information. Diffraction experiments on single crystals provide the most precise data, but sufficiently large specimens (>0.1–0.5 mm3) are often not available. Steady development of instrumentation and data analysis techniques, however, has now made it possible to obtain comparably precise structural information from neutron diffraction experiments on powder samples. Such studies have played a prominent role in solid state physics, chemistry, and materials science in recent years. The special capabilities that have contributed to the success of this technique include atomic cross sections that are often favorable for a particular structural problem, high neutron penetrating power, the excellent resolution achieved with state-of-the-art diffractometers, and steadily advancing analysis techniques that facilitate obtaining structural information from a diverse range of polycrystalline materials.As Axe, Pynn, and Hayter note in their introductory article in this issue of the MRS BULLETIN, atomic scattering cross sections for neutrons are not simply a function of atomic number, as is the case for x-rays. The scattering is predominantly from the nuclei (thus avoiding the form factor diminution observed for x-ray scattering), and coherent neutron scattering cross sections can, generally, be as large for light atoms as for heavy atoms. Light atoms, such as hydrogen (deuterium), oxygen, nitrogen, carbon, or lithium, can therefore be located in the presence of heavier atoms. This advantage has led to the widespread use of neutron powder diffraction for studing metal hydrides and, more recently, oxide superconductors.

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Horiuchi, Hiroyuki. "Diffraction technique applying pulsed neutron source." Bulletin of the Japan Institute of Metals 28, no. 3 (1989): 213–19. http://dx.doi.org/10.2320/materia1962.28.213.

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OHOYAMA, Kenji. "Magnetic Structure Refinements by Neutron Diffraction Technique." RADIOISOTOPES 59, no. 8 (2010): 477–90. http://dx.doi.org/10.3769/radioisotopes.59.477.

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Lee, S. H., and C. F. Majkrzak. "A new technique for polarized neutron diffraction." Physica B: Condensed Matter 267-268 (June 1999): 341–43. http://dx.doi.org/10.1016/s0921-4526(99)00040-x.

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Peters, J., and W. Jauch. "Single Crystal Time-of-Flight Neutron Diffraction." Science Progress 85, no. 4 (November 2002): 297–318. http://dx.doi.org/10.3184/003685002783238744.

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The last century has seen a large development in diffraction techniques. The time-of-flight neutron diffraction method is now so advanced that it provides high precision results for position and thermal parameters, which are complementary to other diffraction results from X-ray sources. Here we review the history of neutron sources, the difficulties encountered with the time-of-flight technique and an outlook for applications. In this context, we will show the limitations of existing neutron sources and the expected advantages of new spallation neutron sources. An overview of all corrections to be taken into account with the wavelength-sorting technique will be presented as well as actual results, how to overcome such problems, and the special difficulty of integration of three-dimensional Bragg peaks.

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Will, G., W. Schäfer, and P. Merz. "Texture Analysis by Neutron Diffraction Using a Linear Position Sensitive Detector." Textures and Microstructures 10, no. 4 (January 1, 1989): 375–87. http://dx.doi.org/10.1155/tsm.10.375.

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Neutron diffraction in connection with a position-sensitive detector is a most powerful technique in texture analysis comparable in time with conventional X-ray laboratory technique. Neutrons measure the global texture of the sample allowing volumes up to several cm3. By using position-sensitive detectors and applying the mathematical procedures of profile analysis multiphase and low symmetry materials can be investigated without serious difficulties. Neutron diffraction experiments operating in transmission record complete diffraction profiles; overlapping lines are unscrambled by profile analysis. Technical and physical specifications of the dedicated detector JULIOS, installed on the texture diffractometer of Bonn University, are given. A hematite ore has been studied by this technique and the results are given.

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Ahmed, R., H. Yu, S. Stewart, L. Edwards, and J. R. Santisteban. "Residual Strain Measurements in Thermal Spray Cermet Coatings via Neutron Diffraction." Journal of Tribology 129, no. 2 (January 9, 2007): 411–18. http://dx.doi.org/10.1115/1.2647503.

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The impact and fatigue resistance of overlay coatings is significantly influenced by the residual strain (or stress) field induced during coating deposition, post-treatment, and in-service loading. Optimization of the residual strain field is therefore critical to the life and performance of components. Nondestructive measurement of these strain fields in relatively thin (300-400μm) thermal spray coatings, however, poses a challenge because conventional techniques, such as deep hole drilling, x-ray diffraction, synchrotron diffraction, and changes in beam curvature either make these techniques destructive and/or provides only a very near-surface strain measurement. This particularly complicates the strain analysis in cermet coatings, e.g., WC-Co deposited by the thermal spraying process, where the low penetration depth of x-ray and synchrotron-diffraction ray can only provide a through thickness measurement of stress or strain profile via the destructive layer removal technique. Recent investigations have therefore concentrated on the use of neutron diffraction technique for such analysis, and this paper reports some of the early findings of the comparison of through thickness strain measurements in relatively thin (400μm) as-sprayed and post-treated WC-12wt.%Co coatings via the neutron diffraction technique. Since neutrons are not charged, they do not interact with the electron cloud surrounding the atom (unlike x-ray); hence, diffraction results from the interaction with the atomic nucleus. Neutrons therefore have greater penetration depth in most engineering materials, and therefore provide a nondestructive through thickness strain measurement. Results of strain measurement are discussed with the structure property relationships and contact fatigue performance, and indicate that post-treatment of these coatings results in harmonization of the strain field within the coating, and at the coating substrate interface. This significantly influences the contact fatigue performance by improving both the cohesive and adhesive strength of these coatings.

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Kawasaki, Takuro, Yasuhiro Inamura, Takayoshi Ito, Takeshi Nakatani, Stefanus Harjo, Wu Gong, and Kazuya Aizawa. "Stroboscopic time-of-flight neutron diffraction during cyclic testing using the event data recording system at J-PARC." Journal of Applied Crystallography 51, no. 3 (May 25, 2018): 630–34. http://dx.doi.org/10.1107/s1600576718006453.

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A time-resolved time-of-flight neutron diffraction technique to characterize the structural properties of materials during cyclic tests has been developed for the neutron diffractometers at J-PARC. Using this technique, diffracted neutrons and the applied cyclic conditions are recorded as event data together with time information. The amplitude and phase of the conditions of all recorded neutron signals can be specified by using the characteristics of the event data. By adopting the developed technique, the behaviors of the crystal lattice and domains of the piezoelectric material in a multilayer-type piezoelectric actuator driven by a cyclic electric field were evaluated. The developed technique enabled the collection and processing of diffraction data for all levels of the applied electric field, as opposed to only the highest and lowest levels. The variation in diffraction intensity during the application of a cyclic electric field was obtained successfully, and the hysteresis-like behaviors of both the lattice strain and the 90° domain switching were revealed.

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Takahashi, Shunichi, Toshihiko Sasaki, Yukio Sato, Kengo Iwafuchi, Hiroshi Suzuki, Yukio Morii, Yasuto Kondo, Ryoichi Monzen, and Yukio Hirose. "Application of Neutron Diffraction Technique to Industrial Materials." Materials Science Forum 571-572 (March 2008): 57–62. http://dx.doi.org/10.4028/www.scientific.net/msf.571-572.57.

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As an important industrial problem, the rolling contact fatigue damage is accumulated in rails during the repeated passage of trains over the rails, and rail failures may occur from the cracks grown in the rails. In order to prevent such rail failures, the estimation of the behavior of internal rail cracks is required based on the exact engineering analysis model as well as conducting rail test to search rail defects. The purposes of this paper are to apply the neutron stress measurement to rails, and to obtain residual stress state in the rails for the above purpose. The rail samples used were those that have been used in service line in Japan for about six years (222 million gross tons). The neutron measurement was conducted using the Residual Stress Analyzer (RESA) of the Japan Atomic Energy Agency (JAEA). The present measurement of stresses in rails by the neutron diffraction method was the first attempt in Japan.

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11

Balagurov, A. M., G. M. Mironova, V. E. Novozchilov, A. I. Ostrovnoy, V. G. Simkin, and V. B. Zlokazov. "The application of the neutron time-of-flight technique for real-time diffraction studies." Journal of Applied Crystallography 24, no. 6 (December 1, 1991): 1009–14. http://dx.doi.org/10.1107/s0021889891006982.

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Real-time neutron powder diffraction and small-angle scattering techniques have been developed on the TOF diffractometer DN-2 at the IBR-2 pulsed reactor at JINR (Dubna) with a total flux on the sample of 107 neutrons cm−2 s−1 and a resolution of about 1%. A special arrangement of the detector system ensures a high counting rate of diffracted neutrons. Depending upon sample type and experimental conditions, the measuring time ts of one neutron pattern varies from a few minutes to several seconds. The performance of the diffractometer is discussed and typical data are shown to demonstrate current achievements using real-time techniques at a pulsed reactor.

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12

Butler, B. D., B. C. Murray, D. G. Reichel, and A. D. Krawitz. "Elastic Constants of Alloys Measured with Neutron Diffraction." Advances in X-ray Analysis 32 (1988): 389–95. http://dx.doi.org/10.1154/s0376030800020693.

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AbstractElastic constants as a function of crystallographic direction have been measured in polycrystalline alloy samples of 17-4PH stainless steel, Ni-Cr-Fe, and Ti-6%AI-4%V using a neutron diffraction technique. The results compare best with the constant stress model of Reuss. It is demonstrated that measurements of stress can be made sampling the bulk of the material using neutrons with an accuracy comparable to more conventional x-ray methods.

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Kohara, S., N. Umesaki, H. Ohno, K. Suzuya, and I. Sakai. "The structure of oxide glasses studied by high-energy x-ray diffraction." Physics and Chemistry of Glasses: European Journal of Glass Science and Technology Part B 61, no. 6 (December 12, 2020): 233–38. http://dx.doi.org/10.13036/17533562.61.6.kohara.

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The use of high‑energy x‑ray diffraction techniques with the latest generation synchrotron sources has created new approaches to study quantitatively the structure of noncrystalline materials. Recently, this technique has been combined with neutron diffraction at pulsed source to provide more detailed and reliable structural information not previously available. This article reviews and summarises recent results obtained from the high energy x‑ray diffraction on several oxide glasses, SiO2, B2O3 and PbSiO3, using bending magnet beamlines at SPring‑8. In particular, it addresses the structural models of the oxide glasses obtained by the reverse Monte Carlo (RMC) modelling technique using both the high energy x‑ray and neutron diffraction data.

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Heacock, B., D. Sarenac, D. G. Cory, M. G. Huber, J. P. W. MacLean, H. Miao, H. Wen, and D. A. Pushin. "Neutron sub-micrometre tomography from scattering data." IUCrJ 7, no. 5 (August 20, 2020): 893–900. http://dx.doi.org/10.1107/s2052252520010295.

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Neutrons are valuable probes for various material samples across many areas of research. Neutron imaging typically has a spatial resolution of larger than 20 µm, whereas neutron scattering is sensitive to smaller features but does not provide a real-space image of the sample. A computed-tomography technique is demonstrated that uses neutron-scattering data to generate an image of a periodic sample with a spatial resolution of ∼300 nm. The achieved resolution is over an order of magnitude smaller than the resolution of other forms of neutron tomography. This method consists of measuring neutron diffraction using a double-crystal diffractometer as a function of sample rotation and then using a phase-retrieval algorithm followed by tomographic reconstruction to generate a map of the sample's scattering-length density. Topological features found in the reconstructions are confirmed with scanning electron micrographs. This technique should be applicable to any sample that generates clear neutron-diffraction patterns, including nanofabricated samples, biological membranes and magnetic materials, such as skyrmion lattices.

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15

Keller, Thomas, Piotr Fabrykiewicz, Radosław Przeniosło, Izabela Sosnowska, and Bernhard Keimer. "Neutron Larmor diffraction on powder samples." Journal of Applied Crystallography 53, no. 1 (February 1, 2020): 88–98. http://dx.doi.org/10.1107/s160057671901611x.

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A hitherto unrecognized resolution effect in neutron Larmor diffraction (LD) is reported, resulting from small-angle neutron scattering (SANS) in the sample. Small distortions of the neutron trajectories by SANS give rise to a blurring of the Bragg angles of the order of a few hundredths of a degree, leading to a degradation of the momentum resolution. This effect is negligible for single crystals but may be significant for polycrystalline or powder samples. A procedure is presented to correct the LD data for the parasitic SANS. The latter is accurately determined by the SESANS technique (spin–echo small-angle neutron scattering), which is readily available on Larmor diffractometers. The analysis technique is demonstrated on LD and SESANS data from α-Fe2O3 powder samples. The resulting d-spacing range agrees with experimental data from high-resolution synchrotron radiation powder diffraction on the same sample.

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Steuwer, Axel, Javier Roberto Santisteban, Philip J. Withers, Lyndon Edwards, and Mike E. Fitzpatrick. "In situdetermination of stresses from time-of-flight neutron transmission spectra." Journal of Applied Crystallography 36, no. 5 (September 8, 2003): 1159–68. http://dx.doi.org/10.1107/s0021889803013748.

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The pulsed neutron transmission diffraction technique exploits the sharp steps in intensity (Bragg edges) appearing in the transmitted spectra of thermal neutrons through polycrystalline materials. In this paper the positions of these edges acquired by the time-of-flight (TOF) technique are used to measure accurately the interplanar lattice distances to a resolution of Δd/d≃ 10−4of specimens subjected toin situuniaxial tensile loading. The sensitivity of the method is assessed for elastically isotropic (b.c.c. ferritic) and anisotropic (f.c.c. austenitic) polycrystalline specimens of negligible and moderately textured steels. For the more anisotropic austenitic steel, the elastic anisotropy is studied with regard to a Pawley refinement, and compared with previous results from conventional neutron diffraction experiments on the same material. It is shown that the method can be used to determine anisotropic strains, diffraction elastic constants, the residual and applied stress state as well as the unstrained lattice parameter by recording transmission spectra at different specimen inclinations, by complete analogy with the sin2ψ technique frequently used in X-ray diffraction. The technique is shown to deliver reliable measures of strain even in the case of moderate texture and elastic anisotropy.

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Santisteban, J. R., L. Edwards, A. Steuwer, and P. J. Withers. "Time-of-flight neutron transmission diffraction." Journal of Applied Crystallography 34, no. 3 (May 22, 2001): 289–97. http://dx.doi.org/10.1107/s0021889801003260.

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The positions of Bragg edges in neutron transmission experiments can be defined with high accuracy using the time-of-flight (TOF) technique on pulsed neutron sources. A new dedicated transmission instrument has been developed at ISIS, the UK spallation source, which provides a precision of Δd/d≃ 10−5in the determination of interplanar distances. This is achieved by fitting a theoretical three-parameter expression to the normalized Bragg edges appearing in the TOF transmission spectra. The technique is demonstrated by experiments performed on iron, niobium and nickel powders. The applicability of using the instrument for the determination of lattice strains in materials has been investigated using a simplein situloading experiment. Details of the calibration process are presented and the dependence of the resolution and the experimental times required by the transmission geometry on the instrumental variables are studied. Finally, the requirements for a Rietveld-type refinement of transmission data and the advantages and limitations over traditional neutron diffraction peak analysis are discussed.

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Lawson, A. C., B. Cort, C. E. Olsen, J. W. Richardson, M. H. Mueller, G. H. Lander, J. A. Goldstone, et al. "Applications of Pulsed Neutron Powder Diffraction to Actinide Elements." Advances in X-ray Analysis 31 (1987): 385–93. http://dx.doi.org/10.1154/s0376030800022205.

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We have been using the technique of pulsed neutron powder diffraction to study several problems in the physics and chemistry of the actinide elements. In these elements one often encounters very complex structures resulting from polymorphic transformations presumably induced by the presence of 5f-electrons. For exampie, at least five distinct structures of plutonium metal are found between room temperature and its melting point of 640°C, and two of the structures are monoclinic! Single crystals are usually not available, and the high resolution which is intrinsic to the time-of-flight powder technique is a powerful tool in the solution of complex structural problems. The relatively low absorption coefficients for neutrons for at least some actinide isotopes is an advantage when surface oxidation is a problem (as in high-temperature experiments) and provides good particle statistics so that high-quality data are available for Rietveld refinement. The low absorption of neutrons by other materials such as vanadium and fused silica enables the use of these materials for the containment of samples in high- and low-temperature environments, and the fixed geometry of the time-of-flight technique simplifies the design of furnaces and cryostats.

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SUZUKI, Hiroshi. "Stress Measurement Technique using Neutron Diffraction and its Applications." Journal of the Vacuum Society of Japan 53, no. 12 (2010): 713–19. http://dx.doi.org/10.3131/jvsj2.53.713.

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Stasiulevicius, R., C. Rodrigues, and C. B. R. Parente. "Natural crystals for use with the neutron diffraction technique." Annals of Nuclear Energy 26, no. 16 (November 1999): 1447–55. http://dx.doi.org/10.1016/s0306-4549(99)00028-6.

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Rekveldt, M. T., T. Keller, and R. Golub. "Larmor precession, a technique for high-sensitivity neutron diffraction." Europhysics Letters (EPL) 54, no. 3 (May 2001): 342–46. http://dx.doi.org/10.1209/epl/i2001-00248-2.

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22

Kennedy, S. J. "Applications of Neutron Powder Diffraction in Materials Research." Advances in X-ray Analysis 38 (1994): 35–46. http://dx.doi.org/10.1154/s0376030800017626.

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Abstract 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.

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Dabas, Dr Seema. "Thermal Neutron Scattering of Un-Aligned Multi-walled Carbon Nanotubes." International Journal for Research in Applied Science and Engineering Technology 10, no. 4 (April 30, 2022): 1346–3149. http://dx.doi.org/10.22214/ijraset.2022.41520.

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Abstract: Neutron scattering is the scattering of free neutrons by matter. This process is used for the investigation of materials. Neutron scattering is an experimental technique which is applied in various areas of physics, physical chemistry, biophysics, crystallography and materials research. Neutron diffraction (elastic scattering) is used for determination of structures of materials. In this paper we attempted to study thermal neutron scattering in randomly un-aligned multi walled carbon nanotubes making use of an anisotropic dynamical model. This model includes the presence of both the surface modes and intertube coupling. Comparison of scattering cross section of un-aligned multiwalled carbon nanotubes has been done with fullerene and graphite. It was concluded that there is a significant difference between the values of scattering cross section for randomly un-aligned multiwalled carbon nanotubes and fullerene at higher values of energy. Keywords: Carbon nanotubes, Elastic scattering, Neutron Diffraction, Frequency distribution function, Specific heat

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24

Faisal, N. H., R. Ahmed, A. K. Prathuru, A. Paradowska, and T. L. Lee. "Measuring Residual Strain and Stress in Thermal Spray Coatings Using Neutron Diffractometers." Experimental Mechanics 62, no. 3 (November 10, 2021): 369–92. http://dx.doi.org/10.1007/s11340-021-00803-9.

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Abstract Background During thermal spray coating, residual strain is formed within the coating and substrates due to thermo-mechanical processes and microstructural phase changes. Objective This paper provides a comprehensive guide to researchers planning to use neutron diffraction technique for thermal spray coatings, and reviews some of these studies. Methods ENGIN-X at the ISIS spallation source is a neutron diffractometer (time-of-flight) dedicated to materials science and engineering with high resolution testing. The focus is on the procedure of using ENGIN-X diffractometer for thermal spray coatings with a view that it can potentially be translated to other diffractometers. Results Number of studies involving neutron diffraction analysis in thermal spray coatings remain limited, partly due to limited number of such strain measurement facilities globally, and partly due to difficulty is applying neutron diffraction analysis to measure residual strain in the thermal spray coating microstructure. Conclusions This technique can provide a non-destructive through-thickness residual strain analysis in thermally sprayed components with a level of detail not normally achievable by other techniques. Neutron sources have been used to measure strains in thermal spray coatings, and here, we present examples where such coatings have been characterised at various neutron sources worldwide, to study residual strains and microstructures. Graphic Abstract

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Lorentzen, T., T. Faurholdt, B. Clausen, and J. Danckert. "Characterization of residual stresses generated during inhomogeneous plastic deformation." Journal of Strain Analysis for Engineering Design 33, no. 3 (April 1, 1998): 243–52. http://dx.doi.org/10.1243/0309324981512968.

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Residual stresses generated by macroscopic inhomogeneous plastic deformation are predicted by an explicit finite element (FE) technique. The numerical predictions are evaluated by characterizing the residual elastic strains by neutron diffraction using two different ( hkl) reflections. Intergranular residual elastic strains between subsets of grains are predicted numerically and verified by neutron diffraction. Subsequently, the measured residual strain profiles in the test samples are modified by the intergranular strains and compared to the engineering predictions of the FE technique. Results compare well and verify the capability of the numerical technique as well as the possibilities of experimental validation using neutron diffraction. The presented experimental and numerical approach will subsequently be utilized for the evaluation of more complicated plastic deformation processes resembling forming operations.

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ABE, Jun, Kotaro SEKINE, Stefanus HARJO, Takayoshi ITO, and Kazuya AIZAWA. "Lattice Strain Measurement in Rock Sample by Neutron Diffraction Technique." Journal of MMIJ 131, no. 4 (2015): 122–28. http://dx.doi.org/10.2473/journalofmmij.131.122.

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Burca, G., J. A. James, W. Kockelmann, M. E. Fitzpatrick, S. Y. Zhang, J. Hovind, and R. van Langh. "A new bridge technique for neutron tomography and diffraction measurements." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 651, no. 1 (September 2011): 229–35. http://dx.doi.org/10.1016/j.nima.2011.01.096.

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Edwards, Alison J. "Neutron Diffraction – Recent Applications to Chemical Structure Determination." Australian Journal of Chemistry 64, no. 7 (2011): 869. http://dx.doi.org/10.1071/ch11234.

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Ficquet, X., Christopher E. Truman, and David John Smith. "Measurement of Residual Stress in an A533B Ferritic Steel Plate Containing a Repair Weld." Materials Science Forum 524-525 (September 2006): 653–58. http://dx.doi.org/10.4028/www.scientific.net/msf.524-525.653.

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The paper presents the results of residual stress measurements on a ferritic steel plate containing a repair weld. The repair was considered representative of that found in the secondary circuit piping in power plant. The paper primarily uses the deep hole drilling (DHD) technique, but compares results found by this technique with those obtained using neutron diffraction. Both sets of measurements confirmed that highly tensile residual stresses exist in the repair weld. The two measurement techniques produced results that were in acceptable agreement, but the neutron diffraction results were consistently higher than the deep hole drilling results. It was thought this was due to the use of a constant stress-free lattice parameter d0 .

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Bruno, G., and B. D. Dunn. "Surface and Bulk Residual Stress in Ti6Al4V Welded Aerospace Tanks." Journal of Pressure Vessel Technology 126, no. 3 (August 1, 2004): 284–92. http://dx.doi.org/10.1115/1.1763932.

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The residual stress (RS) in two curved plates cut from a large welded propellant tank for spacecrafts was investigated nondestructively by neutron and laboratory x-ray diffraction. Each plate had two weld beads symmetric to a central monoblock reinforcement. One plate had received a post-weld heat-treatment. The two nondestructive test techniques successfully determined both the bulk (thickness averaged) and the surface stress state, due to the highly different penetration of these radiations in metals. In the as-welded tank, both neutrons and x-rays show a stress level (both in the axial and hoop directions) higher in the heat affected zone (HAZ) than in the weld pool (300 against 160 MPa). A considerable degree of relaxation annealing was observed by neutron diffraction after the application of the heat treatment. In this case, the hoop stress in the HAZ relaxes from about 300 to about 100 MPa. X-rays also permitted the separate determination of the α and β-phase stresses and the calculation of the macro-RS. The latter showed the bending deformation resulting from the cut of the plates from the original tank. The average stress measured by x-rays was found to be very similar to the RS obtained by neutron diffraction technique.

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Finger, Raphael, Thomas C. Hansen, and Holger Kohlmann. "Simultaneous neutron powder diffraction and Raman spectroscopy – an approach of combining two complementary techniques." Zeitschrift für Kristallographie - Crystalline Materials 236, no. 11-12 (November 22, 2021): 325–28. http://dx.doi.org/10.1515/zkri-2021-2051.

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Abstract Diffraction techniques are well-established methods for crystal structure determination as well as phase identification and quantification. Raman spectroscopy can be a valuable complementary characterization technique, because in contrast to the former it yields also information on amorphous materials and it is a probe for short-range structural effects. The herein presented setup allows for simultaneous neutron diffraction and Raman spectroscopy, shown with a sample of lead sulfate under ambient conditions as a proof of principle. In order to fulfil requirements of both methods, a sapphire single-crystal is used as a sample holder. Practical considerations for successful simultaneous in situ neutron diffraction and Raman spectroscopic measurements are given.

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Santisteban, Javier Roberto, A. Steuwer, L. Edwards, P. J. Withers, and M. E. Fitzpatrick. "Mapping of unstressed lattice parameters using pulsed neutron transmission diffraction." Journal of Applied Crystallography 35, no. 4 (July 18, 2002): 497–504. http://dx.doi.org/10.1107/s0021889802009044.

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Stress measurement by neutron diffraction depends critically on knowledge of the unstressed lattice parameter (a0) of the specimen under study. As a result, measurement of stress profiles in components wherea0is not homogeneous throughout the sample, such as welds or carburized surfaces, can be particularly difficult. An efficient solution to this problem is proposed based on the pulsed neutron transmission diffraction technique. This technique exploits the sharp steps in intensity, the so-called Bragg edges, appearing in the transmitted neutron spectra of polycrystalline materials, such steps being produced by coherent scattering from lattice planes. The position of these Bragg edges as defined by the time-of-flight technique is used to determine precisely local interplanar distances. In this work it is shown that the unstressed lattice parameter of thin specimens subjected to plane stress fields can be defined by recording transmission spectra at different sample inclinations, in complete analogy with the sin2ψ technique used in X-ray diffraction. Moreover, by using an array of detectors it is possible to produce a radiographic `image' ofa0for plane specimens or thin sections out of three-dimensional ones. The capability of the technique is exemplified by mapping the changes ina0for a ferritic weld that was used as a round robin sample in an international program for standardization of stress measurements by neutron diffraction.

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Qin, L. C., and L. D. Marks. "Electron diffraction contrast of fluxons." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 1102–3. http://dx.doi.org/10.1017/s0424820100089822.

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Partial penetration of an applied external magnetic field occurs in type-II superconductors. The properties of magnetic fluxons are important in determining the critical current density of type-II superconductors as it is the mobility of the fluxon lattice that limits the high value of critical current density of superconductors. There have been various experimental techniques in use to study the fluxons, e.g. the decoration technique, neutron diffraction, electron holography and scanning tunneling microscopy.Noting that in the thin crystal case the magnetic fluxes have a tangential component which deflects incident electrons, we explore the possibility of using conventional electron diffraction contrast technique to observe the fluxons. This is accomplished by using the London model for the vortex in thin crystals and the classical electromagnetic theory based on Maxwell equations to construct the magnetic field of a fluxon.

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Feng, Hao, Rana Ashkar, Nina Steinke, Robert Dalgliesh, Nickolay V. Lavrik, Ivan I. Kravchenko, and Roger Pynn. "Grating-based holographic diffraction methods for X-rays and neutrons: phase object approximation and dynamical theory." Journal of Applied Crystallography 51, no. 1 (February 1, 2018): 68–75. http://dx.doi.org/10.1107/s1600576717016867.

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A method dubbed grating-based holography was recently used to determine the structure of colloidal fluids in the rectangular grooves of a diffraction grating from X-ray scattering measurements. Similar grating-based measurements have also been recently made with neutrons using a technique called spin-echo small-angle neutron scattering. The analysis of the X-ray diffraction data was done using an approximation that treats the X-ray phase change caused by the colloidal structure as a small perturbation to the overall phase pattern generated by the grating. In this paper, the adequacy of this weak phase approximation is explored for both X-ray and neutron grating holography. It is found that there are several approximations hidden within the weak phase approximation that can lead to incorrect conclusions from experiments. In particular, the phase contrast for the empty grating is a critical parameter. While the approximation is found to be perfectly adequate for X-ray grating holography experiments performed to date, it cannot be applied to similar neutron experiments because the latter technique requires much deeper grating channels.

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Ezeilo, A. N., and G. A. Webster. "Neutron diffraction analysis of the residual stress distribution in a bent bar." Journal of Strain Analysis for Engineering Design 35, no. 4 (May 1, 2000): 235–46. http://dx.doi.org/10.1243/0309324001514387.

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A well-characterized residual stress distribution resulting from four-point bending has been analysed using the neutron diffraction technique. Residual stresses were obtained from the strains measured at discrete positions through the bent bar on the (111) and (311) crystal planes of a nickel-based alloy using the appropriate diffraction elastic constants. In addition a profile refinement method was used to determine the residual stresses from average strains from all the diffraction peaks in the spectrum. The measured residual stress profiles have also been compared with strain gauge data and with analytical and finite element predictions. It has been established that the profile refinement approach gives stresses which most closely match those obtained by the non-diffraction techniques.

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Kraan, W. H., C. T. Kaiser, and M. Th Rekveldt. "High-resolution Neutron Diffraction using Larmor Precession." Journal of Applied Crystallography 31, no. 5 (October 1, 1998): 742–47. http://dx.doi.org/10.1107/s0021889898004956.

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A polarized neutron beam travels through a precession coil with fieldBand the intensity in a detector behind the analyser is recorded as a function ofB. Fourier transformation of the intensity signal gives the wavelength spectrum of the beam entering the detector. Any (diffraction) experiment can be set up in the optical pathway between the analyser and detector. This technique is applied in an array of high-resolution diffraction experiments along the path of the neutron beam through a bent Al strip. The detector intensities are measured only over a small range ofBaway from B=0. The phase shift between the intensity signals from compressed/extended regions, relative to the signal from a reference region in the strip, reveals the deformation of the Al lattice.

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Reim, J. D., E. Rosén, W. Schweika, M. Meven, N. R. Leo, D. Meier, M. Fiebig, et al. "Structural invariance upon antiferromagnetic ordering in geometrically frustrated swedenborgite, CaBaCo2Fe2O7." Journal of Applied Crystallography 47, no. 6 (November 28, 2014): 2038–47. http://dx.doi.org/10.1107/s1600576714023528.

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Centimetre-sized single crystals of high-quality CaBaCo2Fe2O7were synthesized by the optical floating zone technique. The metal-to-metal stoichiometry and oxygen content were confirmed by spectroscopy and thermal reduction experiments. The hexagonal symmetryP63mc(No. 186) well describes the powder X-ray and neutron diffraction as well as single-crystal neutron diffraction at all measured temperatures. This symmetry is also consistent with optical second harmonic generation data obtained between 10 and 295 K. However, a satisfactory structure description from single-crystal neutron diffraction data needs an oxygen split position. Specific heat, magnetic susceptibility and powder neutron diffraction data indicate a magnetic phase transition atTN= 159 K to an antiferromagnetic ground state, but with a persisting hexagonal symmetry and intrinsic geometric frustration.

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Gutmann, M. J., W. Kockelmann, L. C. Chapon, and P. G. Radaelli. "Phase imaging using time-of-flight neutron diffraction." Journal of Applied Crystallography 39, no. 1 (January 12, 2006): 82–89. http://dx.doi.org/10.1107/s0021889805041580.

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A technique that allows the spatial distribution of crystallographic phases in the interior of an object to be reconstructed from neutron time-of-flight (TOF) diffraction is described. To this end, the shift of the Bragg peaks due to the so-called `geometrical aberration' is exploited. A collimated incident white beam is used to perform a translational or rotational scan of the object whilst collecting a TOF data set for each sample position or orientation. Depending on the location of any scattering material along the line of the incident beam path through the object, the measuredd-spacings of the corresponding Bragg peaks are shifted with respect to their nominal values, which are attained only at the geometrical centre of the instrument. Using a formula that is usually employed to correct for sample offset, the phase distribution along the incident beamline can be directly reconstructed, without the need to perform a tomographic reconstruction. Results are shown from a demonstration experiment carried out on a cylindrical Al container enclosing an arrangement of Cu and Fe rods. On the basis of this formalism, an optimized experimental geometry is described and the potential and limits of this technique are explored, as are its applicability to X-ray and constant-wavelength neutron diffraction.

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Ezeilo, A. N., and G. A. Webster. "Advances in Neutron Diffraction for Engineering Residual Stress Measurements." Textures and Microstructures 33, no. 1-4 (January 1, 1999): 151–71. http://dx.doi.org/10.1155/tsm.33.151.

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The increasing awareness amongst engineers and designers, of the significance of residual stresses in influencing the useful lifetimes of engineering components, has resulted in more demanding expectations being placed on the methods used to obtain these stresses. The neutron diffraction technique is emerging as the most attractive measuring method as the residual stresses can usually be obtained non-destructively to depths of up to 40 mm in some common engineering materials. Although it is a relatively new technique it has been used to measure the residual stresses in a range of engineering materials introduced by a wide variety of manufacturing processes such as welding, quenching, machining, shot peening, cold hole expansion and autofrettage.In this paper the neutron diffraction technique for non-destructive residual stress measurements will be described including methods used to validate the measurements. Precautions that should be taken in order to obtain reliable measurements are outlined. Procedures being investigated in order to produce a code of practice will be presented. A representative selection of stress distributions developed by a range of manufacturing processes is examined. Some comparisons are made with strain gauge, X-ray and numerical predictions. It is shown how the results can be of benefit in engineering stress analysis.

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Festa, G., A. Pietropaolo, F. Grazzi, E. Barzagli, A. Scherillo, and E. M. Schooneveld. "Neutron diffraction measurements at the INES diffractometer using a neutron radiative capture based counting technique." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 654, no. 1 (October 2011): 373–76. http://dx.doi.org/10.1016/j.nima.2011.04.032.

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Onuki, Yusuke, Takashi Hirano, Kazuki Umemura, Shigeo Sato, and Toshiro Tomida. "In Situ Neutron Diffraction Measurement during Bainite Transformation and Accompanying Carbon Enrichment in Austenite at iMATERIA, J-PARC MLF." Materials Science Forum 1016 (January 2021): 1079–84. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.1079.

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The authors have developed the in situ neutron diffraction technique focusing on bainite transformation during austempering. Thanks to the features of time-of-flight type neutron diffraction, textures, phase fractions and lattice parameters can be simultaneously measured at high temperature. In this paper, the design of experimental equipment and analytical approach are mainly described.

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Li, Fankang, Hao Feng, Alexander N. Thaler, Steven R. Parnell, Lowell Crow, Masaaki Matsuda, Feng Ye, Tsuyoshi Kimura, Jaime A. Fernandez-Baca, and Roger Pynn. "New capabilities in high-resolution neutron Larmor diffraction at ORNL." Journal of Applied Crystallography 51, no. 3 (April 13, 2018): 584–90. http://dx.doi.org/10.1107/s1600576718004211.

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Using superconducting magnetic Wollaston prisms, high-resolution neutron Larmor diffraction has been implemented at the High-Flux Isotope Reactor of Oak Ridge National Laboratory (ORNL), Tennesse, USA. This technique allows the inverse relationship between the achievable diffraction resolution and the usable neutron flux to be overcome. Instead of employing physically tilted radio-frequency spin flippers, the method uses magnetic Wollaston prisms which are electromagnetically tuned by changing the field configurations in the device. As implemented, this method can be used to measure lattice-spacing changes induced, for example, by thermal expansion or strain with a resolution of Δd/d ≃ 10−6, and the splitting of sharp Bragg peaks with a resolution of Δd/d = 3 × 10−4. The resolution for discerning a change in the profile of a Bragg peak is Δd/d < 10−5. This is a remarkable degree of precision for a neutron diffractometer as compact as the one used in this implementation. Higher precision could be obtained by implementing this technique in an instrument with a larger footprint. The availability of this technique will provide an alternative when standard neutron diffraction methods fail and will greatly benefit the scientific communities that require high-resolution diffraction measurements.

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Maekawa, Akira, Toru Oumaya, Michiyasu Noda, Shigeru Takahashi, and Toru Saito. "Residual Stress Distribution in Austenitic Stainless Steel Pipe Butt-Welded Joint Measured by Neutron Diffraction Technique." Materials Science Forum 652 (May 2010): 116–22. http://dx.doi.org/10.4028/www.scientific.net/msf.652.116.

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This paper describes residual stress measurements and analysis of austenitic stainless steel pipe with a butt-welded joint. The measurements were done with neutron diffraction and strain gauge techniques. The measured results had typical characteristics of butt-welded pipe regarding both the decline of stress along the axial direction and the bending distribution of axial stress along the radial direction. The measured residual stress distribution by neutron diffraction was shifted more to the tensile side than that by the finite element method simulation. However, the measured radial and axial strains, except for the hoop strain determined by neutron diffraction, coincided well with analysis strains. The hoop strain was actually equivalent strain converted by a correction method because a different lattice plane had to be used to measure hoop strain. This might be one reason why the difference occurred. Therefore, future study of the correction method would be desirable.

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Fujiwara, S., Y. Takezawa, Y. Sugimoto, and K. Wakabayashi. "Neutron fiber diffraction measurements of muscle using the contrast variation technique." Acta Crystallographica Section A Foundations of Crystallography 64, a1 (August 23, 2008): C562—C563. http://dx.doi.org/10.1107/s0108767308081920.

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Uden, Jeremy, Francesco Grazzi, Francesco Civita, Antonella Scherillo, Heather Richardson, Laura Bartoli, and Marco Zoppi. "Time-of-flight neutron diffraction: a new analytical technique for conservation?" Journal of the Institute of Conservation 35, no. 1 (March 2012): 25–39. http://dx.doi.org/10.1080/19455224.2012.681615.

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Lychagina, Tatiana, Alexander Zisman, Ekaterina Yashina, and Dmitry Nikolayev. "Directly Verifiable Neutron Diffraction Technique to Determine Retained Austenite in Steel." Advanced Engineering Materials 20, no. 4 (October 30, 2017): 1700559. http://dx.doi.org/10.1002/adem.201700559.

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Martel, P., and Iain E. P. Taylor. "Neutron diffraction and proton nuclear magnetic resonance: complementary probes of in situ cellulose dimensions and primary plant cell wall structure." Canadian Journal of Botany 71, no. 10 (October 1, 1993): 1375–80. http://dx.doi.org/10.1139/b93-164.

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Neutron diffraction was used to monitor the microscopic structure of cell walls from etiolated bean (Phaseolus vulgaris L.) hypocotyls after successive chemical fractionations with ammonium oxalate – oxalic acid and potassium hydroxide. Wide angle neutron scattering measurements showed that there was no highly ordered long range structure and confirm results from proton nuclear magnetic resonance techniques that there is alteration of the cell wall cellulose by chemical fractionations. Small angle scattering measurements showed that the residual cellulose microfibrils increased in diameter from 75.0 ± 2.3 to 110.0 ± 4.2 Å (1 Å = 0.1 nm) after successive treatments with ammonium oxalate – oxalic acid and potassium hydroxide. The technique has potential applications to study cellulose dimensions in situ. Key words: plant cell wall, cellulose dimensions, neutron diffraction, proton NMR.

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Puphal, Pascal, Stephan Allenspach, Christian Rüegg, and Ekaterina Pomjakushina. "Floating Zone Growth of Sr Substituted Han Purple: Ba0.9Sr0.1CuSi2O6." Crystals 9, no. 5 (May 27, 2019): 273. http://dx.doi.org/10.3390/cryst9050273.

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We present a route to grow single crystals of Ba 0.9 Sr 0.1 CuSi 2 O 6 suitable for inelastic neutron studies via the floating zone technique. Neutron single crystal diffraction was utilized to check their bulk quality and orientation. Finally, the high quality of the grown crystals was proven by X-ray diffraction and magnetic susceptibility.

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Fry, A. Tony, and Jerry D. Lord. "Measuring the Variation of Residual Stress with Depth: A Validation Exercise for Fine Incremental Hole Drilling." Materials Science Forum 524-525 (September 2006): 531–37. http://dx.doi.org/10.4028/www.scientific.net/msf.524-525.531.

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Hole drilling along with X-Ray diffraction, is one of the most widely used techniques for measuring residual stress, but the conventional approach is limited in the near surface detail that can be resolved. Because of concerns regarding the levels of induced residual stress that might develop during machining and surface treatment processes, there is significant interest in developing a technique that can obtain near surface residual stress information by the application of fine increment hole drilling. Through a cross comparison with X-ray diffraction and neutron diffraction the procedure of fine incremental drilling has been validated, and the advantages of this technique demonstrated.

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Voronin, Vladimir, Valery Fedorov, Sergey Semenikhin, and Yaroslav Berdnikov. "Neutron spin rotation effect at Laue diffraction in a weakly deformed and nonabsorbing crystal with no center of symmetry." EPJ Web of Conferences 219 (2019): 06003. http://dx.doi.org/10.1051/epjconf/201921906003.

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The effect of the neutron spin rotation at Laue diffraction in a weakly deformed noncentrosymmetric and transparent for the neutrons crystal has been theoretically described and experimentally investigated. This effect arises in the deformed crystal because of the curvature of the neutron trajectory in the crystal. A certain type of deformation leads to the escape outside the crystal of one of the two neutron waves excited at Laue diffraction. This two waves propagate in the crystal without a center of symmetry in electric fields with the opposite sign. In this case the spin of the remaining neutron wave will be rotating relative to the original direction due to the interaction of the magnetic moment of the moving neutron with the crystal's intracrystalline electric field. In a perfect undeformed crystal such spin rotation effect is absent. There is only a depolarization of the beam since both waves in opposite electric fields are present with the same amplitudes. A technique for controlled deformation of a perfect single crystal by creating a temperature gradient has been developed. Thus a new possibility to measure the electric fields which act on the neutron in noncentrosymmetric crystals has been realized. There also appeared a way to control these fields in experiments on the study of the neutron fundamental properties.

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Journal articles on the topic 'Neutron diffraction technique'

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