Quantitative texture analysis using the NOMAD time-of-flight neutron diffractometer

2021 ◽  
Vol 54 (3) ◽  
Author(s):  
N. E. Peterson ◽  
J. R. Einhorn ◽  
C. M. Fancher ◽  
J. R. Bunn ◽  
E. A. Payzant ◽  
...  
Keyword(s):  
Reasonable Agreement ◽  
National Laboratory ◽  
Experimental Methods ◽  
Al Alloy ◽  
Spallation Neutron Source ◽  
Analysis Method ◽  
Texture Measurement ◽  
Measurement Capability ◽  
Oak Ridge ◽  
Neutron Diffractometer

Strategies for efficient and reliable texture measurements have been explored using the Nanoscale Ordered Materials Diffractometer (NOMAD) at the Spallation Neutron Source located at Oak Ridge National Laboratory (ORNL). To test these strategies, the texture of an Al alloy was also investigated using another neutron diffraction instrument, a constant-wavelength neutron diffractometer (NRSF2) located at the High Flux Isotope Reactor, also at ORNL. Reasonable agreement was found across the two experimental methods, but differences in overall texture strength and the symmetry of some components were noted, depending on the data reduction and analysis method selected. On the basis of these results, potential improvements are identified which would enhance the texture measurement capability on NOMAD.

scholarly journals The Macromolecular Neutron Diffractometer MaNDi at the Spallation Neutron Source

2015 ◽  
Vol 48 (4) ◽  
pp. 1302-1306 ◽  
Author(s):  
Leighton Coates ◽  
Matthew J. Cuneo ◽  
Matthew J. Frost ◽  
Junhong He ◽  
Kevin L. Weiss ◽  
...  
Keyword(s):  
Data Collection ◽  
Single Crystals ◽  
Neutron Source ◽  
Diffraction Data ◽  
National Laboratory ◽  
Spallation Neutron Source ◽  
Oak Ridge ◽  
Neutron Diffractometer ◽  
Macromolecular Systems ◽  
Neutron Time

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

The macromolecular neutron diffractometer (MaNDi) at the Spallation Neutron Source, Oak Ridge: enhanced optics design, high-resolution neutron detectors and simulated diffraction

2010 ◽  
Vol 43 (3) ◽  
pp. 570-577 ◽  
Author(s):  
L. Coates ◽  
A. D. Stoica ◽  
C. Hoffmann ◽  
J. Richards ◽  
R. Cooper
Keyword(s):  
High Resolution ◽  
Neutron Source ◽  
National Laboratory ◽  
High Energy ◽  
Neutron Guide ◽  
Spallation Neutron Source ◽  
Neutron Detectors ◽  
Spectral Window ◽  
Oak Ridge ◽  
Neutron Diffractometer

The macromolecular neutron diffractometer MaNDi is currently under construction at the first target station of the Spallation Neutron Source at Oak Ridge National Laboratory. This instrument will collect neutron diffraction data from small single crystals (0.1–1 mm3) with lattice constants between 100 and 300 Å, as well as data from less well ordered systems such as fibers. A focusing neutron guide has been designed to filter the high-energy neutron component of the spectrum and to provide a narrow beam with a wide spectral window and angular divergence almost insensitive to neutron wavelength. The system includes a final interchangeable section of neutron guide and two slits, which enable tuning of the horizontal and vertical beam divergence between 0.12 and 0.80° (full width at half-maximum) at the sample position. This allows the trading of intensity for resolution, depending on the scientific requirements. Efforts to enhance and develop suitable high-resolution neutron detectors at an affordable price are also discussed. Finally, the parameters of the neutron guide and detectors were used to simulate diffraction from a large unit cell.

scholarly journals High-resolution neutron time-of-flight measurements for light water at the Spallation Neutron Source (SNS), Oak Ridge National Laboratory

2020 ◽  
Vol 239 ◽  
pp. 14005
Author(s):  
Luiz Leal ◽  
Vaibhav Jaiswal ◽  
Alexander I. Kolesnikov
Keyword(s):  
Experimental Data ◽  
Neutron Source ◽  
National Laboratory ◽  
Operating Conditions ◽  
Spallation Neutron Source ◽  
Light Water ◽  
Oak Ridge ◽  
Oak Ridge National Laboratory ◽  
Thermal Scattering ◽  
Reactor Operating

Series of light water inelastic neutron scattering experiments have been made at the Oak Ridge National Laboratory (ORNL), Spallation Neutron Source (SNS) covering temperatures ranging from 295 K to 600 K and pressures of 1 bar and 150 bar. The temperatures and pressures ranges correspond to that of pressurized light water reactors. The inelastic scattering measurements will help the development of light water thermal scattering kernels, also known as S (α,β) thermal scattering law (TSL), in a consistent fashion given the amount and the quality of the measured data. Light water thermal scattering evaluations available in existing nuclear data libraries have certain limitations and pitfalls. This paper introduces the state of the art of the light water thermal scattering cross-section data not only for room temperature but as well as for reactor operating temperatures, i.e. 550 - 600 K. During the past few years there has been a renewed interest in re-investigating the existing TSL models and utilize the recent experimental data or perform molecular dynamics simulations. It should be pointed out that no single TSL evaluation is based entirely on experimental data and one has to rely on TSL models or a combination of both. New TOF measurement of light water at the SNS, with a detailed description of the experimental setup, measurement conditions, and the associated foreseen results is presented in this paper. The analysis of the experimental data would help in validating the existing approach based on old experimental data or based on molecular dynamic simulations using classical water models, knowledge of which is very important to generate TSL libraries at reactor operating conditions.

Four-circle single-crystal neutron diffractometer at the High Flux Isotope Reactor

2011 ◽  
Vol 44 (3) ◽  
pp. 655-658 ◽  
Author(s):  
Bryan C. Chakoumakos ◽  
Huibo Cao ◽  
Feng Ye ◽  
Alexandru D. Stoica ◽  
Mihai Popovici ◽  
...  
Keyword(s):  
High Resolution ◽  
High Intensity ◽  
Structural Changes ◽  
National Laboratory ◽  
Control Program ◽  
High Flux ◽  
Oak Ridge ◽  
Neutron Diffractometer ◽  
Flat Condition ◽  
Continuous Scanning

A four-circle neutron diffractometer with a new multi-wafer 331 Si monochromator has been installed and commissioned on a thermal beamline at the High Flux Isotope Reactor at Oak Ridge National Laboratory. The instrument is well suited to studies of nuclear and magnetic structures as a function of composition and temperature, resolving symmetry changes (lattice distortions and local structural changes), mapping the evolution of complex magnetic phases, determining hydrogen bonding, analyzing nuclear and spin densities, mapping diffuse scattering, and exploring fiber diffraction. Three incident wavelengths are available, 1.000, 1.536 and 2.540 Å, with intensities of 2.5 × 106, 2.2 × 107and 8.0 × 106 neutrons cm−2 s−1, respectively. Either high-resolution or high-intensity modes are possible by horizontal bending of the monochromator. With increased bending of the monochromator, the incident flux on the sample passes through a maximum, increasing by ×2.0 for 1.000 Å, by ×3.5 for 1.536 Å and by ×3.5 for 2.540 Å, as compared to the flat condition. The flux increases because the lattice strain in the silicon crystals increases. The ω-scan peak width increases with monochromator curvature and this widthversusscattering angle flattens. Given these effects, the monochromator bending can be adjusted to deliver high intensity primarily for crystal structure refinements or high resolution for resolving symmetry changes. In addition to the traditional step-scanning mode, a more efficient continuous-scanning mode was developed, and both these are implemented through aLabView-based control program,i.e.a modified version of theSPICEsoftware package. A 4 K closed-cycle helium refrigerator is permanently mounted on the χ-circle of the goniometer to provide temperature control between 4 and 450 K.

scholarly journals Protein crystallization and initial neutron diffraction studies of the photosystem II subunit PsbO

2017 ◽  
Vol 73 (9) ◽  
pp. 525-531 ◽  
Author(s):  
Martin Bommer ◽  
Leighton Coates ◽  
Holger Dau ◽  
Athina Zouni ◽  
Holger Dobbek
Keyword(s):  
Photosystem Ii ◽  
Neutron Diffraction ◽  
Active Site ◽  
Room Temperature ◽  
Protein Crystallization ◽  
National Laboratory ◽  
Spallation Neutron Source ◽  
Oak Ridge ◽  
Psbo Protein ◽  
Counter Diffusion

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 mm3crystal at room temperature using the MaNDi single-crystal diffractometer at the Spallation Neutron Source, Oak Ridge National Laboratory.

scholarly journals Light yield of cold undoped CsI crystal down to 13 keV and the application of such crystals in neutrino detection

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
Keyu Ding ◽  
Dmitry Chernyak ◽  
Jing Liu
Keyword(s):  
Energy Range ◽  
Neutron Source ◽  
National Laboratory ◽  
Light Yield ◽  
Radioactive Source ◽  
Experimental Result ◽  
Spallation Neutron Source ◽  
Oak Ridge ◽  
Neutrino Detection ◽  
Electron Equivalent

AbstractThe light yield of an undoped CsI crystal at about 77 Kelvin was measured to be $$33.5 \, \pm \, 0.7$$ 33.5 ± 0.7  photo-electrons (PE) per keV electron-equivalent (keVee) in the energy range of [13, 60] keVee using X and $$\gamma $$ γ -rays from an $$^{241}$$ 241 Am radioactive source. Based on this experimental result, the performance of 10 kg cryogenic inorganic scintillating crystals coupled to SiPM arrays to probe non-standard neutrino interactions through the detection of coherent elastic neutrino-nucleus scatterings at the spallation neutron source, Oak Ridge National Laboratory, was examined in detail.

scholarly journals Atomic pair distribution function analysis from the ARCS chopper spectrometer at the Spallation Neutron Source

2009 ◽  
Vol 42 (4) ◽  
pp. 724-725 ◽  
Author(s):  
E. S. Božin ◽  
P. Juhás ◽  
W. Zhou ◽  
M. B. Stone ◽  
D. L. Abernathy ◽  
...  
Keyword(s):  
Neutron Source ◽  
Powder Diffraction ◽  
Function Analysis ◽  
National Laboratory ◽  
Distribution Functions ◽  
Spallation Neutron Source ◽  
Los Alamos National Laboratory ◽  
Oak Ridge ◽  
Atomic Pair Distribution Function ◽  
Atomic Pair

Neutron powder-diffraction-based atomic pair distribution functions (PDFs) are reported from the new wide-angular-range chopper spectrometer ARCS at the Spallation Neutron Source at Oak Ridge National Laboratory. The spectrometer was run in white-beam mode with no Fermi chopper. The PDF patterns of Ni and Al2O3were refined using the PDFfit method and the results compared with data collected at the NPDF diffractometer at Los Alamos National Laboratory. The resulting fits are of high quality, demonstrating that quantitatively reliable powder diffraction data can be obtained from ARCS when operated in this configuration.

scholarly journals New capabilities in high-resolution neutron Larmor diffraction at ORNL

2018 ◽  
Vol 51 (3) ◽  
pp. 584-590 ◽  
Author(s):  
Fankang Li ◽  
Hao Feng ◽  
Alexander N. Thaler ◽  
Steven R. Parnell ◽  
Lowell Crow ◽  
...  
Keyword(s):  
High Resolution ◽  
Lattice Spacing ◽  
Inverse Relationship ◽  
Bragg Peak ◽  
National Laboratory ◽  
Scientific Communities ◽  
Oak Ridge ◽  
Neutron Diffractometer ◽  
Standard Neutron ◽  
The One

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.

scholarly journals Event-based processing of neutron scattering data at the Spallation Neutron Source

2018 ◽  
Vol 51 (3) ◽  
pp. 616-629 ◽  
Author(s):  
Garrett E. Granroth ◽  
Ke An ◽  
Hillary L. Smith ◽  
Pamela Whitfield ◽  
Joerg C. Neuefeind ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Neutron Source ◽  
National Laboratory ◽  
Scattering Data ◽  
Spallation Neutron Source ◽  
Pump Probe ◽  
New Era ◽  
Oak Ridge ◽  
Battery Degradation ◽  
Event Based

The Spallation Neutron Source at Oak Ridge National Laboratory, USA, ushered in a new era of neutron scattering experiments through the use of event-based data. Tagging each neutron event allows pump–probe experiments, measurements with a parameter asynchronous to the source, measurements with continuously varying parameters and novel ways of testing instrument components. This contribution will focus on a few examples. A pulsed magnet has been used to study diffraction under extreme fields. Continuous ramping of temperature is becoming standard on the POWGEN diffractometer. Battery degradation and phase transformations under heat and stress are often studied on the VULCAN diffractometer. Supercooled Al2O3 was studied on NOMAD. A study of a metallic glass through its glass transition was performed on the ARCS spectrometer, and the effect of source variation on chopper stability was studied for the SEQUOIA spectrometer. Besides a summary of these examples, an overview is provided of the hardware and software advances to enable these and many other event-based measurements.

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