scholarly journals Grazing incidence scattering

2018 ◽  
Vol 188 ◽  
pp. 04002 ◽  
Author(s):  
Max Wolff
Keyword(s):  
Self Assembly ◽  
Born Approximation ◽  
Scattering Length ◽  
Grazing Incidence ◽  
The Self ◽  
Scattered Intensity ◽  
Distorted Wave ◽  
Polymer Micelles ◽  
Distorted Wave Born Approximation ◽  
Scattering Geometry

Reflectometry experiments probe the scattering length density along the normal of interfaces by analysing the specularly scattered intensity. Lateral fluctuations result in intensity scattered away from the specular condition. In this paper the principles and peculiarities of grazing incidence scattering experiments are explained. One specific example, the self assembly of polymer micelles close to interfaces, is taken as a show case in order to introduce the scattering geometry and accessible length scales. The basic idea of the distorted wave Born approximation is lined out and some scientific examples are summarized.

Grazing-incidence small-angle X-ray scattering from thin polymer films with lamellar structures – the scattering cross section in the distorted-wave Born approximation

2006 ◽  
Vol 39 (3) ◽  
pp. 433-442 ◽  
Author(s):  
P. Busch ◽  
M. Rauscher ◽  
D.-M. Smilgies ◽  
D. Posselt ◽  
C. M. Papadakis
Keyword(s):  
Thin Films ◽  
Polymer Films ◽  
Small Angle ◽  
Born Approximation ◽  
Grazing Incidence ◽  
Thin Polymer Films ◽  
Distorted Wave ◽  
Distorted Wave Born Approximation ◽  
X Ray ◽  
Thin Polymer

Grazing-incidence small-angle X-ray or neutron scattering of thin polymer films reveals information about the ordering and preferential orientations of the phase-separated microdomains within the films. The grazing-incidence geometry enhances the surface sensitivity; however, the scattering has to be treated within the framework of the distorted-wave Born approximation. In this work, the case of thin films with lamellar mesostructure is studied, where the orientation of the lamellae is either perpendicular or parallel to the film interfaces. For perpendicular lamellae, Bragg rods are found, which are extended along the film normal, whereas for parallel lamellae, peaks along the film normal appear. The positions of the maxima present in the latter case are explained by accounting for refraction at the film surface and reflection at the film–substrate interface. The results are relevant for thin films of lamellar diblock copolymers.

scholarly journals Unwarping GISAXS data

IUCrJ ◽  
2018 ◽  
Vol 5 (6) ◽  
pp. 737-752 ◽  
Author(s):  
Jiliang Liu ◽  
Kevin G. Yager
Keyword(s):  
Born Approximation ◽  
Grazing Incidence ◽  
Initial Guess ◽  
Reciprocal Space ◽  
Scattering Data ◽  
Distorted Wave ◽  
Distorted Wave Born Approximation ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission And Reflection

Grazing-incidence small-angle X-ray scattering (GISAXS) is a powerful technique for measuring the nanostructure of coatings and thin films. However, GISAXS data are plagued by distortions that complicate data analysis. The detector image is a warped representation of reciprocal space because of refraction, and overlapping scattering patterns appear because of reflection. A method is presented to unwarp GISAXS data, recovering an estimate of the true undistorted scattering pattern. The method consists of first generating a guess for the structure of the reciprocal-space scattering by solving for a mutually consistent prediction from the transmission and reflection sub-components. This initial guess is then iteratively refined by fitting experimental GISAXS images at multiple incident angles, using the distorted-wave Born approximation (DWBA) to convert between reciprocal space and detector space. This method converges to a high-quality reconstruction for the undistorted scattering, as validated by comparing with grazing-transmission scattering data. This new method for unwarping GISAXS images will broaden the applicability of grazing-incidence techniques, allowing experimenters to inspect undistorted visualizations of their data and allowing a broader range of analysis methods to be applied to GI data.

Multi-channel distorted-wave Born approximation for rovibrational transition rates in molecular collisions

2021 ◽  
Vol 155 (3) ◽  
pp. 034105
Author(s):  
Taha Selim ◽  
Arthur Christianen ◽  
Ad van der Avoird ◽  
Gerrit C. Groenenboom
Keyword(s):  
Born Approximation ◽  
Transition Rates ◽  
Distorted Wave ◽  
Distorted Wave Born Approximation ◽  
Molecular Collisions

Analysing powers and differential cross sections of (3He,p) reactions on 6Li and 7Li at low energy

1995 ◽  
Vol 73 (1-2) ◽  
pp. 74-84 ◽  
Author(s):  
D. Baddou ◽  
C. Rioux ◽  
R. J. Slobodrian ◽  
J. M. Nelson
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Born Approximation ◽  
Low Energy ◽  
Angular Distributions ◽  
Differential Cross Sections ◽  
Distorted Wave ◽  
Distorted Wave Born Approximation ◽  
Nucleon Transfer ◽  
Cluster Transfer

Angular distributions of the differential cross sections and analysing powers were measured at an energy of 4.6 MeV. The results are compared with the distorted wave Born approximation predictions for two-nucleon transfer and for a deuteron-cluster transfer. The agreement is qualitative at best, and a discussion of alternatives to improve it is presented.

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