Structural transitions of hard-sphere colloids studied by spin-echo small-angle neutron scattering

2003 ◽  
Vol 36 (6) ◽  
pp. 1417-1423 ◽  
Author(s):  
Timofei Krouglov ◽  
Wim G. Bouwman ◽  
Jeroen Plomp ◽  
M. Theo Rekveldt ◽  
Gert Jan Vroege ◽  
...  

The structure of hard-sphere colloidal suspensions is measured at different concentrations using the recently developed spin-echo small-angle neutron scattering (SESANS) technique. It is shown that SESANS measures real-space correlations ranging from the size of a single particle for a dilute suspension to several particle diameters for a concentrated suspension, glass and crystalline state.

2005 ◽  
Vol 357 (3-4) ◽  
pp. 452-455 ◽  
Author(s):  
Timofey Kruglov ◽  
Wim G. Bouwman ◽  
Jeroen Plomp ◽  
M. Theo Rekveldt ◽  
Gert Jan Vroege ◽  
...  

Soft Matter ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 17-21
Author(s):  
Gregory N. Smith ◽  
Victoria J. Cunningham ◽  
Sarah L. Canning ◽  
Matthew J. Derry ◽  
J. F. K. Cooper ◽  
...  

Concentrated dispersions of polymer nanoparticles with high contrast can be studied using SESANS in real space.


2003 ◽  
Vol 36 (1) ◽  
pp. 109-116 ◽  
Author(s):  
Oktay Uca ◽  
Wim G. Bouwman ◽  
M. Theo Rekveldt

Spin-echo small-angle neutron scattering (SESANS) is a new kind of SANS technique enabling measurements to be made directly in real space from a range of a few nanometres up to micrometres. In this paper it is shown by calculations on models that SESANS measures correlations directly. Furthermore, the effect of polydispersity and structure factor has been studied. An exact expression for the correlation function has been derived in the case of random systems, such as fractal systems.


2008 ◽  
Vol 41 (5) ◽  
pp. 868-885 ◽  
Author(s):  
Robert Andersson ◽  
Léon F. van Heijkamp ◽  
Ignatz M. de Schepper ◽  
Wim G. Bouwman

Spin-echo small-angle neutron scattering (SESANS) is, in contrast to conventional small-angle neutron scattering (SANS), a real-space technique. SESANS measures the projection of the density–density correlation function of a sample, rather than, as in SANS, its Fourier transform. This paper introduces a toolkit for interpretion and analysis of a SESANS measurement. Models that are used in SANS are discussed and translated into a SESANS formalism. These models can be used to analyse and fit the data obtained by SESANS. Dilute, concentrated, random, fractal and anisotropic density distributions are considered. Numerical methods used to calculate the projection from numerical data are presented, either by using Fourier transformation orviathe real-space pair correlation function.


2001 ◽  
Vol 34 (5) ◽  
pp. 639-645 ◽  
Author(s):  
Jinkui Zhao

Two-dimensional spin echo small-angle neutron scattering experiments that measure the vector-length distribution function, or pair-distance distribution function, in real space are discussed. The proposed diffractometer uses two cylindrically symmetric magnetic fields with conically shaped front and end faces to enable experiments in two dimensions. It also features a π/2 neutron spin flipper to make the effective analyzing direction of the analyzer perpendicular to the polarizing direction of the polarizer. The theoretical aspect of one-dimensional spin echo small-angle neutron scattering experiments is also explored. The relationship between the correlation function from one-dimensional experiments and the vector-length distribution function is established, and interpretation of this correlation function in real space is presented.


2003 ◽  
Vol 36 (1) ◽  
pp. 117-124 ◽  
Author(s):  
Timofei Krouglov ◽  
Ignatz M. de Schepper ◽  
Wim G. Bouwman ◽  
M. Theo Rekveldt

Spin-echo small-angle neutron scattering (SESANS) is a novel real-space scattering technique. SESANS measures a correlation-like functionG(Z), the meaning of which was unknown until now. Here a direct real-space interpretation ofG(Z) through the particle scattering density and pair correlation function is given. One-dimensional and two-dimensional SESANS are compared. The case of non-interacting particles is considered in detail with an explicit geometrical interpretation. General methods for the calculation of structural parameters, such as the total scattering length and the radius of gyration, are developed. Analytical expressions ofG(Z) for non-interacting solid spheres, hollow spheres and Gaussian coils are derived. The case of solid spheres is compared with experimental data.


2006 ◽  
Vol 39 (2) ◽  
pp. 252-258 ◽  
Author(s):  
Sergey V. Grigoriev ◽  
Wicher H. Kraan ◽  
M. Theo Rekveldt ◽  
Timofey Kruglov ◽  
Wim G. Bouwman

A novel real-space scattering technique, spin-echo small-angle neutron scattering for magnetic samples, is described. Previously, this method has been exploited for non-magnetic samples only, in order to measure the nuclear density correlation function. Magnetic scattering is different from nuclear scattering as in the former a partial neutron spin-flip that affects the phase accumulation of the Larmor precession occurs just at the moment of scattering. Because of this intrinsic property of magnetic scattering, one can use a magnetic sample as a flipper in the spin-echo technique. This enables the separation of the magnetic contribution from other sources of scattering. Particular features of the technique are pointed out. Some model examples are considered. The similarity and the differences of magnetic SESANS with respect to the technique of three-dimensional neutron depolarization are discussed. The theoretical description is proven by experiments.


2010 ◽  
Vol 132 (17) ◽  
pp. 174509 ◽  
Author(s):  
Xin Li ◽  
Chwen-Yang Shew ◽  
Yun Liu ◽  
Roger Pynn ◽  
Emily Liu ◽  
...  

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