scholarly journals Grazing Incidence Small-Angle Neutron Scattering: Background Determination and Optimization for Soft Matter Samples

2021 ◽  
Vol 11 (7) ◽  
pp. 3085
Author(s):  
Tetyana Kyrey ◽  
Marina Ganeva ◽  
Judith Witte ◽  
Artem Feoktystov ◽  
Stefan Wellert ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Soft Matter ◽  
Grazing Incidence ◽  
Solid Substrate ◽  
Sample Cell ◽  
Reflection And Transmission ◽  
Transmitted Beam ◽  
Angle Scattering

Grazing incidence small-angle neutron scattering (GISANS) provides access to interfacial properties, e.g., in soft matter on polymers adsorbed at a solid substrate. Simulations in the frame of the distorted wave Born approximation using the BornAgain software allow to understand and quantify the scattering pattern above and below the sample horizon, in reflection and transmission, respectively. The small-angle scattering from the interfacial layer, visible around the transmitted beam, which might contribute also on the side of the reflected beam, can be understood in this way and be included into the analysis. Background reduction by optimized sample cell design is supported by simulations, paving the way for an optimized GISANS cell.

Small Angle Neutron Scattering Studies of Blends of Protonated Linear Polystyrene with Crosslinked Deuterated Polystyrene

1989 ◽  
Vol 171 ◽  
Author(s):  
Robert M. Briber ◽  
Barry J. Bauer
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Crosslink Density ◽  
Single Phase ◽  
Linear Chain ◽  
Free Energies ◽  
Scattering Function ◽  
Angle Scattering ◽  
Divinyl Benzene

ABSTRACTSmall angle neutron scattering (SANS) has been used to study the scattering function and thermodynamics of blends of linear protonated polystyrene (PSH) and crosslinked deuterated polystyrene (PSD). Two series of samples were synthesized. In both cases the samples were made by dissolving the linear PSH in deuterated (d8) styrene monomer containing a small amount of divinyl benzene as a crosslinker which was then polymerized to form the PSD network around the linear PSH chains. The samples were all made at a concentration of 50/50 by weight PSD/PSH. A special effort was made to keep the samples single phase so that SANS could be used to study the thermodynamics of the system and compare with theory. This entailed working at relatively low crosslink densities (<1 mole % crosslink units). Series 1 is a set of samples with the same crosslink density varying the length of the linear chain. Series 2 is a set of samples containing the same length linear chain varying the crosslink density systematically. By extrapolating S(q) obtained from SANS to q=O the zero angle scattering, S(O), was obtained. S(O) is inversely proportional to the second derivative of the free energy with respect to composition, ∂2 (Δf/kT)/∂ø2. Assuming additivity of the free energies of mixing and elasticity, the portion of the zero angle scattering due to elasticity is calculated.

Comment on “Cholesterol solubility limit in lipid membranes probed by small angle neutron scattering and MD simulations” by S. Garg et al., Soft Matter, 2014, 10, 9313

Soft Matter ◽  
2015 ◽  
Vol 11 (27) ◽  
pp. 5580-5581
Author(s):  
Richard M. Epand ◽  
Diana Bach ◽  
Ellen Wachtel
Keyword(s):  
Phase Separation ◽  
Neutron Scattering ◽  
Small Angle ◽  
Lipid Membranes ◽  
Small Angle Neutron Scattering ◽  
Soft Matter ◽  
Md Simulations ◽  
Solubility Limit ◽  
Phospholipid Bilayers ◽  
Cholesterol Solubility

As consistently described in the literature, the solubility limit of cholesterol in phospholipid bilayers is defined by its phase separation and crystallization.

scholarly journals Simulations of foil-based spin-echo (modulated) small-angle neutron scattering with a sample using McStas

2021 ◽  
Vol 54 (1) ◽  
pp. 195-202
Author(s):  
Wim G. Bouwman ◽  
Erik B. Knudsen ◽  
Linda Udby ◽  
Peter Willendrup
Keyword(s):  
Magnetic Field ◽  
Elastic Scattering ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Spin Echo ◽  
Transmitted Beam ◽  
Further Development ◽  
Theory And Experiments ◽  
Good Agreement

For the further development of spin-echo techniques to label elastic scattering it is necessary to perform simulations of the Larmor precession of neutron spins in a magnetic field. The details of some of these techniques as implemented at the reactor in Delft are simulated. First, the workings of the magnetized foil flipper are simulated. A full virtual spin-echo small-angle neutron scattering instrument is built and tested without and with a realistic scattering sample. It is essential for these simulations to have a simulated sample that also describes the transmitted beam of unscattered neutrons, which usually is not implemented for the simulation of conventional small-angle neutron scattering (SANS) instruments. Finally, the workings of a spin-echo modulated small-angle neutron scattering (SEMSANS) instrument are simulated. The simulations are in good agreement with theory and experiments. This setup can be extended to include realistic magnetic field distributions to fully predict the features of future Larmor labelling elastic-scattering instruments. Configurations can now be simulated for more complicated combinations of SANS with SEMSANS.

scholarly journals KWS-1: Small-angle scattering diffractometer

2015 ◽  
Vol 1 ◽  
Author(s):  
Henrich Frielinghaus ◽  
Artem Feoktystov ◽  
Ida Berts ◽  
Gaetano Mangiapia
Keyword(s):  
High Resolution ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Small Angle Scattering ◽  
Angle Scattering

The KWS-1, which is operated by JCNS, Forschungszentrum Jülich, is a small-angle neutron scattering diffractometer dedicated to high resolution measurements.

Conceptual design of the grazing-incidence focusing small-angle neutron scattering (gif-SANS) instrument at CPHS

2021 ◽  
pp. 1-5
Author(s):  
Huarui Wu ◽  
Weihang Hong ◽  
Yao Zhang ◽  
Pulin Bai ◽  
Wenbo Mo ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Conceptual Design ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
High Performance ◽  
Grazing Incidence ◽  
The Other ◽  
Tsinghua University ◽  
Neutron Sources ◽  
Sans Instrument

Developing small-angle neutron scattering techniques at compact accelerator-driven neutron sources (CANS) is of great importance for expanding the user community and advancing CANS capability. At the Compact Pulsed Hadron Source (CPHS) at Tsinghua University, neutron-focusing mirrors are under intensive research to address the challenge. A grazing-incidence focusing SANS (gif-SANS) project is initialized. It employs a nested supermirror assembly with a large collecting area to achieve ⩾ 10 5 n/s neutron intensity at Q min ⩽ 0.007 Å − 1 . It will equip two detectors, one being a 3He detector for normal Q-range measurements, and the other being a high-resolution detector for extending the Q min down to 10 − 3 Å − 1 . In this work, we present the conceptual design of the gif-SANS at CPHS. Such a scheme is conducive to enable high-performance SANS measurements at CANS.

Resolution functions of time-of-flight small-angle neutron scattering instruments with rectangular apertures

2007 ◽  
Vol 40 (1) ◽  
pp. 40-50 ◽  
Author(s):  
B. Grabcev
Keyword(s):  
Gravitational Field ◽  
Elastic Scattering ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Time Of Flight ◽  
Careful Analysis ◽  
Mathematical Relationship ◽  
Angle Scattering ◽  
Neutron Wavelength

Analytic forms are found for resolution functions of small-angle neutron scattering instruments. The expressions are developed as a function of momentum transfer (Q) rather than separately in terms of neutron wavelength (λ) and scattering angle (θ). Effects caused by the gravitational field as well as by quasi-elastic scattering are included. Explicit analytic forms for the transmission functions are proposed for both the incident and scattered beams, enabling careful analysis of any problem regarding small-angle scattering experiments. Due to the reciprocal mathematical relationship between λ, θ andQ, [λ, θ] space is employed to approach different aspects of the topic. Applications to time-of-flight instruments with rectangular apertures, including the choice of the most convenient instrumental parameters, the analysis of smearing effects and the data reduction toQspace, are presented.

scholarly journals Microstructure and water distribution in catalysts for polymer electrolyte fuel cells, elucidated by contrast variation small-angle neutron scattering

2019 ◽  
Vol 52 (4) ◽  
pp. 791-799 ◽  
Author(s):  
Satoshi Koizumi ◽  
Satoru Ueda ◽  
Takumi Inada ◽  
Yohei Noda ◽  
Robert A. Robinson
Keyword(s):  
Fuel Cells ◽  
Neutron Scattering ◽  
Polymer Electrolyte ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Water Distribution ◽  
Grazing Incidence ◽  
Polymer Electrolyte Fuel Cells ◽  
Contrast Variation ◽  
Mixed Water

By using small-angle neutron scattering (SANS) reinforced by scanning electron microscopy, the fine structure of catalysts for polymer electrolyte fuel cells has been investigated. The experimental data resulting from contrast variation with mixed light and heavy water (H2O/D2O) are well described by a core–shell model with fluctuations in concentration between water and Nafion. In particular, SANS obtained with the mixed water ratio 30/70, which corresponds to a matching point between mixed water and Nafion, shows a broad scattering maximum, which is attributed to a 5 nm-thick Nafion shell on the surface of the larger carbon particles. After swelling by water, the ionomer layer absorbs water at the 17 wt% level. By changing the H2O/D2O ratio, it was further confirmed that the catalyst with the ionomer exhibits water repellence, whereas the bare catalyst without the ionomer is wetted by water. Because it is very difficult to extract more information, for instance regarding the Pt–Nafion interactions, by means of small-angle scattering, reflectometry and grazing-incidence scattering experiments with neutrons should be attempted on a model catalyst prepared on a flat substrate.

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