Correction method for the asymmetry of the tangential beam in Couette (or Searle) geometry used in rheo-small-angle neutron scattering

2004 ◽  
Vol 37 (3) ◽  
pp. 438-444 ◽  
Author(s):  
Florian Nettesheim ◽  
Ulf Olsson ◽  
Peter Lindner ◽  
Walter Richtering
Keyword(s):  
Neutron Scattering ◽  
Cross Sections ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Correction Method ◽  
Shear Cell ◽  
The Asymmetry ◽  
The Difference ◽  
Scattering Cross Sections ◽  
Final Expression

A method of correcting the asymmetry in the scattering of the tangential beam configuration in a rheo-small-angle neutron scattering experiment is proposed. The asymmetry of the scattering in the tangential beam configuration can be attributed to the difference in pathlength for neutrons that are scattered toward compared with those which are scattered away from the axis of rotation of the shear cell. The pathlength problem is solved and a final expression for the two-dimensional scattering intensity is given. The results from these calculations are compared with experimental data, which offer a different option to correct this asymmetry, namely by just measuring the scattering of H2O/D2O mixtures with absolute scattering cross sections identical to those of the respective samples. However, the situation for anisotropic media is more complex and the correction procedure described here is less effective.

Small-Angle Neutron Scattering from YBa2Cu3O7 and Bi2Sr2CaCu2O8 Near the Critical Temperature

1994 ◽  
Vol 376 ◽  
Author(s):  
C. D. Frost ◽  
G.L. Squires
Keyword(s):  
Critical Temperature ◽  
Sample Preparation ◽  
Neutron Scattering ◽  
Cross Sections ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Crystalline Defects ◽  
Scattering Potential ◽  
The Difference ◽  
Scattering Cross Sections

ABSTRACTOne of the 30 meter small-angle neutron scattering spectrometers at NIST has been used to measure the scattering from YBa2Cu3O7 and Bi2Sr2CaCu2O8 at a range of temperatures from 35 K to 135 K with wavevector transfers Q from 0.01 Å-1 to 0.08 Å-1. Considerable attention was paid to sample preparation in order to reduce the background scattering from crystalline defects and stoichiometric variations in the sample. For both materials, the difference in the differential scattering cross-sections at the critical temperature Tc and at temperatures of Tc ± 20 K showed considerable structure in Q, corresponding to spatial variations in the neutron scattering potential with Fourier components of wavelength of the order of 100 Å.

Sans Measurement of Deuterium-Dislocation Correlation in Palladium

1989 ◽  
Vol 166 ◽  
Author(s):  
Brent J. Heuser ◽  
G.C. Summerfield ◽  
J.S. King ◽  
J.E. Epperson
Keyword(s):  
Neutron Scattering ◽  
Cross Section ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Room Temperature ◽  
Gas Pressure ◽  
Solution Phase ◽  
Pressure Cell ◽  
Scattering Cross ◽  
The Difference

ABSTRACTSmall angle neutron scattering (SANS) measurements have been made on deformed polycrystal palladium samples with and without deuterium dissolved in the solution phase (a) at room temperature. Concentrations were held constant during SANS experiments by an equilibrium gas pressure cell. The difference scattering cross section for the same sample with and without deuterium loading has a 1/Q behavior (Q=4Φ/λsinθ/2) at intermediate values of Q. At very low values of Q the dependence is much stronger than 1/Q. The 1/Q behavior is attributed to deuterium trapping close to long dislocation cores forming rod-like scattering structures.

Isotope effects in solution small-angle X-ray scattering

1999 ◽  
Vol 32 (1) ◽  
pp. 113-114 ◽  
Author(s):  
Stephen J. Henderson
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Isotope Effects ◽  
X Rays ◽  
Light Water ◽  
X Ray ◽  
X Ray Scattering ◽  
The Difference ◽  
Ray Scattering

While the difference between using heavy and light water as solvents for small-angle neutron scattering experiments is well known, the lesser difference for the case of small-angle X-ray scattering with these same isotopes of water has, as yet, not been reported. This difference for the case of X-rays is discussed and quantified for several familiar materials: polystyrene latexes, proteins and lipids.

The measurement of neutron scattering cross sections at small angle

1986 ◽  
Vol 96 (1-4) ◽  
pp. 13-16
Author(s):  
Qi Huei-Quan ◽  
Liu Yun-Chang ◽  
Chen Zhen-Peng ◽  
Wu Xue-Chao ◽  
Wang Wan-Hong ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Cross Sections ◽  
Small Angle ◽  
Scattering Cross ◽  
Scattering Cross Sections

scholarly journals A small-angle neutron scattering investigation of rigid polyelectrolytes under shear

2003 ◽  
Vol 36 (4) ◽  
pp. 1000-1005 ◽  
Author(s):  
E. Mendes ◽  
S. Viale ◽  
O. Santin ◽  
M. Heinrich ◽  
S. J. Picken
Keyword(s):  
Neutron Scattering ◽  
Cross Sections ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Deuterated Water ◽  
Shear Rates ◽  
Scattering Spectrum ◽  
High Shear Rates ◽  
Low Concentrations ◽  
Small Shear

Solutions of a rigid polyelectrolyte molecule, sulfo-poly(phenyleneterephthalamide) (SPTTA), in deuterated water have been investigated using small-angle neutron scattering. At low concentrations (1 wt%) the scattering spectrum presents a soft maximum similar to that of the interaction of rod-like objects. Two counterions are used, H+and Li+, and it is shown that aggregation is favoured as the proportion of Li+counterions increases. When kept at rest at room temperature, the solutions exhibit spontaneous birefringence. A 1 wt% solution was investigated under shear and it is shown that a very small shear rate is needed to produce a very strong alignment of rod-like objects. Such alignment saturates at high shear rates. Upon cessation of shear, a very long relaxation time is observed. The set of results strongly suggest aggregation of rigid polyelectrolyte molecules into long needles exhibiting very small cross sections.

Absolute Calibration of Small-Angle Neutron Scattering Data of a Double-Crystal Diffractometer

1997 ◽  
Vol 30 (5) ◽  
pp. 857-861 ◽  
Author(s):  
F. Carsughi ◽  
D. Bellmann ◽  
J. Kulda ◽  
M. Magnani ◽  
M. Stefanon
Keyword(s):  
Neutron Scattering ◽  
Cross Section ◽  
Cross Sections ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Scattering Data ◽  
Absolute Calibration ◽  
Double Crystal ◽  
Similar Materials ◽  
Double Crystal Diffractometer

Small-angle neutron scattering (SANS) experiments generally provide the absolute SANS cross sections and this allows quantitative results to be obtained; however, data collected at double-crystal diffractometers are frequently not normalized to absolute cross sections and they are used only for qualitative analysis. In point-geometry diffractometers, the normalization is done by comparing the scattered intensities to those of samples of known cross sections or by measuring the direct-beam intensity; in the double-crystal diffractometer, the incident flux information is contained in the rocking curve measured without a sample and this feature can therefore be used to normalize the scattered intensities to the SANS cross sections. A sample of thickness 1 mm of the Ni-based superalloy UDIMET 520 was analyzed at a double-crystal diffractometer; the SANS cross section obtained by the proposed procedure compares well with the SANS cross section found for similar materials by using conventional point-geometry diffractometers and calibrated by light water.

scholarly journals Magnetic Small-Angle Neutron Scattering

2021 ◽  
Author(s):  
Andreas Michels
Keyword(s):  
Neutron Scattering ◽  
Cross Sections ◽  
Small Angle ◽  
Spin Glasses ◽  
Small Angle Neutron Scattering ◽  
Continuum Theory ◽  
Real Space ◽  
Theoretical Background ◽  
Magnetic Interactions ◽  
Comprehensive Treatment

This book provides the first extensive treatment of magnetic small-angle neutron scattering (SANS). The theoretical background required to compute magnetic SANS cross sections and correlation functions related to long-wavelength magnetization structures is laid out; and these concepts are scrutinized based on the discussion of experimental neutron data. Regarding prior background knowledge, some familiarity with the basic magnetic interactions and phenomena, as well as scattering theory, is desired. The target audience comprises Ph.D. students and researchers working in the field of magnetism and magnetic materials who wish to make efficient use of the magnetic SANS method. Besides revealing the origins of magnetic SANS (Chapter 1), and furnishing the basics of the magnetic SANS technique (Chapter 2), much of the book is devoted to a comprehensive treatment of the continuum theory of micromagnetics (Chapter 3), as it is relevant for the study of the elastic magnetic SANS cross section. Analytical expressions for the magnetization Fourier components allow one to highlight the essential features of magnetic SANS and to analyze experimental data both in reciprocal (Chapter 4) and real space (Chapter 6). Chapter 5 provides an overview of the magnetic SANS of nanoparticles and so-called complex systems (e.g., ferrofluids, magnetic steels, spin glasses, and amorphous magnets). It is this subfield where major progress is expected to be made in the coming years, mainly via the increased use of numerical micromagnetic simulations (Chapter 7), which is a very promising approach for the understanding of the magnetic SANS from systems exhibiting nanoscale spin inhomogeneity.

A vapor barrier Couette shear cell for small angle neutron scattering measurements

2002 ◽  
Vol 73 (6) ◽  
pp. 2345-2354 ◽  
Author(s):  
L. Porcar ◽  
W. A. Hamilton ◽  
P. D. Butler ◽  
G. G. Warr
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Shear Cell ◽  
Scattering Measurements

Dependence of small-angle neutron scattering contrast on the difference in thermal expansions of phases in two-phase alloys

2009 ◽  
Vol 42 (6) ◽  
pp. 981-989 ◽  
Author(s):  
Pavel Strunz ◽  
Ralph Gilles ◽  
Debashis Mukherji ◽  
Michael Hofmann ◽  
Dominique del Genovese ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Elevated Temperatures ◽  
Base Alloy ◽  
Integral Intensity ◽  
Two Phase ◽  
The Difference ◽  
The Individual

Theoretical expressions describing small-angle neutron scattering (SANS) contrast dependence on temperature in the region where no phase-composition changes occur were derived for two-phase Ni superalloys. The theory is based on the difference in thermal expansion of the two primary phases, γ and γ′. The simulations show that the scattering contrast temperature evolution is significant enough to be considered inin situSANS experiments with superalloys at elevated temperatures. The simulations performed show that the magnitude of the scattering contrast at room temperature is firmly connected with the particular shape of the scattering contrast temperature dependence. This fact can be used for determination of the scattering contrast without a knowledge of the compositions of the individual phases. The theoretical expressions derived for scattering contrast were proven experimentally on an Ni–Fe-base alloy, DT706. The evolution of lattice parameters of both the matrix and the precipitate phases was obtained from anin situwide-angle neutron diffraction experiment. The theoretical scattering contrast dependence was then successfully fitted to the measured SANS integral intensity.

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