Diffuse scattering with spin analysis using a supermirror polarizer and 5 supermirror analyzers: Results on paramagnetic scattering, crystal field transitions, separation of coherent and incoherent scattering in liquid sodium using time of flight analysis

1982 ◽  
Author(s):  
O. Schärpf
Keyword(s):  
Crystal Field ◽  
Diffuse Scattering ◽  
Time Of Flight ◽  
Incoherent Scattering ◽  
Liquid Sodium ◽  
Spin Analysis

A single-crystal time-of-flight neutron diffractometer at a spallation neutron source

2007 ◽  
Vol 40 (4) ◽  
pp. 799-807 ◽  
Author(s):  
Miwako Takahashi ◽  
Ken-ichi Ohshima ◽  
Masatoshi Arai
Keyword(s):  
Phase Transitions ◽  
Single Crystal ◽  
Neutron Source ◽  
Diffuse Scattering ◽  
Time Of Flight ◽  
Magnetic Scattering ◽  
Spallation Neutron Source ◽  
Neutron Diffractometer ◽  
Incommensurate Structures ◽  
Asymmetric Pulse

A single-crystal diffractometer using the time-of-flight (TOF) Laue technique had been operated for studies of structural and magnetic disorder and phase transitions in alloys and magnetic materials at the pulsed spallation neutron source facility of the KEK Neutron Science Laboratory (KENS). In various sample environments, the diffractometer has demonstrated its usefulness in measurements of diffuse scattering for studying local structures, and in surveys of reciprocal space for studying phase transitions and incommensurate structures under the conditions of varying temperature and magnetic field. Particular emphasis is placed on the fact that though the instrument did not receive high-flux neutrons for long wavelengths suitable for the studies of magnetic scattering, it gave good results on the observations of magnetic diffuse scattering and superlattice reflections. Remarks and future tasks of the TOF Laue technique are discussed in relation to the asymmetric pulse shape, separation of the inelastic scattering, and dependence of data correction on the sample quality.

Oscillatory diffuse scattering study by time-of-flight neutron scattering

2008 ◽  
Vol 403 (17) ◽  
pp. 2557-2560 ◽  
Author(s):  
Khairul Basar ◽  
Xianglian ◽  
Sainer Siagian ◽  
Takashi Sakuma ◽  
Haruyuki Takahashi ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Diffuse Scattering ◽  
Time Of Flight ◽  
Scattering Study

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

2016 ◽  
Vol 49 (2) ◽  
pp. 497-506 ◽  
Author(s):  
Tara M. Michels-Clark ◽  
Andrei T. Savici ◽  
Vickie E. Lynch ◽  
Xiaoping Wang ◽  
Christina M. Hoffmann
Keyword(s):  
Diffuse Scattering ◽  
National Laboratory ◽  
Time Of Flight ◽  
Statistical Weight ◽  
Single Step ◽  
Reciprocal Space ◽  
Bragg Diffraction ◽  
Scattering Data ◽  
Oak Ridge ◽  
Integration Data

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

Neutron time-of-flight measurements of diffuse scattering

1997 ◽  
Vol 241-243 ◽  
pp. 201-203 ◽  
Author(s):  
D.A Keen ◽  
M.J Harris ◽  
W.I.F David
Keyword(s):  
Diffuse Scattering ◽  
Time Of Flight ◽  
Neutron Time ◽  
Flight Measurements

scholarly journals Computation of diffuse scattering arising from one-phonon excitations in a neutron time-of-flight single-crystal Laue diffraction experiment

2015 ◽  
Vol 48 (4) ◽  
pp. 1122-1129 ◽  
Author(s):  
Matthias J. Gutmann ◽  
Gabriella Graziano ◽  
Sanghamitra Mukhopadhyay ◽  
Keith Refson ◽  
Martin von Zimmerman
Keyword(s):  
Single Crystal ◽  
Diffuse Scattering ◽  
Density Functional ◽  
Time Of Flight ◽  
Diffraction Experiment ◽  
Functional Theory ◽  
Laue Diffraction ◽  
Phonon Excitation ◽  
Neutron Time ◽  
Characteristic Features

Direct phonon excitation in a neutron time-of-flight single-crystal Laue diffraction experiment has been observed in a single crystal of NaCl. At room temperature both phonon emission and excitation leave characteristic features in the diffuse scattering and these are well reproduced usingabinitiophonons from density functional theory (DFT). A measurement at 20 K illustrates the effect of thermal population of the phonons, leaving the features corresponding to phonon excitation and strongly suppressing the phonon annihilation. A recipe is given to compute these effects combining DFT results with the geometry of the neutron experiment.

Thermal Diffuse Scattering in Neutron Time-of-Flight Powder Patterns

1989 ◽  
Vol 166 ◽  
Author(s):  
Michael J. Radler
Keyword(s):  
Transition Metal ◽  
Inelastic Scattering ◽  
Diffuse Scattering ◽  
Elevated Temperatures ◽  
Time Of Flight ◽  
Significant Fraction ◽  
Thermal Diffuse Scattering ◽  
Neutron Time ◽  
Thermal Diffuse ◽  
Profile Refinement

ABSTRACTInelastic scattering from lattice phonons contributes a significant fraction of the observed Bragg intensity in time of flight neutron powder patterns of transition metal monoxides at elevated temperatures. Ignoring this thermal diffuse scattering (TDS) leads to errors in the site occupations of defects present in these materials. The intensity from one phonon TDS has been calculated as a function of time-of-flight and used to correct the measured intensities. The effect of this correction on the results of Rietveld profile refinement is discussed.

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