Small Angle Electron Scattering From Vacuum Condensed Metallic Films

1968 ◽  
Vol 26 ◽  
pp. 380-381
Author(s):  
J. Silcox ◽  
R. H. Wade
Keyword(s):  
Electron Scattering ◽  
Small Angle ◽  
Ring Structure ◽  
Two Dimensional ◽  
Metallic Films ◽  
Micro Structure ◽  
Angle Scattering ◽  
The Fourier Transform ◽  
Source Of Information ◽  
Kinematical Theory

Recent work has drawn attention to the possibilities that small angle electron scattering offers as a source of information about the micro-structure of vacuum condensed films. In particular, this serves as a good detector of discontinuities within the films. A review of a kinematical theory describing the small angle scattering from a thin film composed of discrete particles packed close together will be presented. Such a model could be represented by a set of cylinders packed side by side in a two dimensional fluid-like array, the axis of the cylinders being normal to the film and the length of the cylinders becoming the thickness of the film. The Fourier transform of such an array can be regarded as a ring structure around the central beam in the plane of the film with the usual thickness transform in a direction normal to the film. The intensity profile across the ring structure is related to the radial distribution function of the spacing between cylinders.

SLADS: a parallel code for direct simulations of scattering of large anisotropic dense nanoparticle systems

2017 ◽  
Vol 50 (3) ◽  
pp. 951-958 ◽  
Author(s):  
Sen Chen ◽  
Juncheng E ◽  
Sheng-Nian Luo
Keyword(s):  
Analytical Solutions ◽  
Small Angle ◽  
Real Space ◽  
Small Angle Scattering ◽  
Two Dimensional ◽  
X Ray ◽  
X Ray Scattering ◽  
Angle Scattering ◽  
Parallel Code ◽  
Diffraction Patterns

SLADS(http://www.pims.ac.cn/Resources.html), a parallel code for direct simulations of X-ray scattering of large anisotropic dense nanoparticle systems of arbitrary species and atomic configurations, is presented. Particles can be of arbitrary shapes and dispersities, and interactions between particles are considered. Parallelization is achieved in real space for the sake of memory limitation. The system sizes attempted are up to one billion atoms, and particle concentrations in dense systems up to 0.36. Anisotropy is explored in terms of superlattices. One- and two-dimensional small-angle scattering or diffraction patterns are obtained.SLADSis validated self-consistently or against cases with analytical solutions.

Longitudinal magnetoresistance in silver and copper between 4.2 and 35 °K

1967 ◽  
Vol 302 (1468) ◽  
pp. 83-98 ◽  
Keyword(s):  
Relaxation Time ◽  
Electron Scattering ◽  
Small Angle ◽  
Time Approximation ◽  
Long Wavelength ◽  
Relaxation Time Approximation ◽  
Angle Scattering ◽  
Different Types ◽  
Pure Single Crystal ◽  
Longitudinal Magnetoresistance

Longitudinal magnetoresistance has been measured in a number of single crystals of silver and one very pure single crystal of copper in fields up to 65 kG and at temperatures between 4.2 and 35 °K. The purpose of the work has been to investigate the effects of different types of electron scattering, in particular small angle scattering. It has been found that at 4.2 °K impure crystals obey the relaxation time approximation fairly well, whereas crystals that have been purified (by oxidation at 800 °C) do not. Above 4.2 °K, the addition of long wavelength phonons has caused the magnetoresistance to increase substantially, as predicted by Pippard (1964), but agreement with Pippard’s theory is only qualitative. To account for the results a more detailed treatment of the scattering is required.

Maximum-entropy method as a routine tool for determination of particle size distributions by small-angle scattering

2004 ◽  
Vol 37 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Dragomir Tatchev ◽  
Rainer Kranold
Keyword(s):  
Particle Size ◽  
Fourier Transform ◽  
Small Angle ◽  
Maximum Entropy Method ◽  
Entropy Method ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Angle Scattering ◽  
The Fourier Transform

Several aspects of the application of the maximum-entropy method (MEM) to the determination of particle size distributions by small-angle scattering (SAS) are discussed. The `historic' version of the MEM produces completely satisfying results. Limiting the data error from below (i.e.imposing a minimal relative error) is proposed as a solution of some convergence problems. The MEM is tested against the Fourier transform technique. The size distribution of Pb particles in an Al–Pb alloy is determined by the MEM and the Fourier transform technique. The size distributions obtained by transmission electron microscopy (TEM) and SAXS show partial agreement.

Application of Grazing-Incidence Small-Angle X-Ray Scattering Technique to Semiconducting Composite Materials

2005 ◽  
Vol 475-479 ◽  
pp. 1097-1100 ◽  
Author(s):  
T. Ogawa ◽  
H. Niwa ◽  
Hiroshi Okuda ◽  
Shojiro Ochiai
Keyword(s):  
Small Angle ◽  
Grazing Incidence ◽  
Two Dimensional ◽  
Dimensional Model ◽  
X Ray ◽  
X Ray Scattering ◽  
Angle Scattering ◽  
Two Dimensional Model ◽  
Scattering Technique ◽  
Best Fitting

Grazing-incidence small-angle scattering (GI-SAXS) technique was applied to self-assembled Ge islands capped with Si. GI-SAXS has a merit over TEM and AFM that the structure of islands buried in a cap layer for stabilization can be evaluated nondestructively. By analyzing the scattering patterns, the size of Ge islands was estimated to be about 5 nm in height and 26 nm in diameter, with the islands density of 4.2×1014/m2. From the best fitting of two-dimensional model intensity to the experiments, the shape of the islands was deduced

New attempt to combine scanning electron microscopy and small-angle scattering in reciprocal space

2019 ◽  
Vol 52 (4) ◽  
pp. 783-790 ◽  
Author(s):  
Satoshi Koizumi ◽  
Satoru Ueda ◽  
Yukihiro Nishikawa ◽  
Takeshi Terao ◽  
Norio Kubo
Keyword(s):  
Electron Emission ◽  
Small Angle ◽  
Secondary Electron ◽  
Scattering Amplitude ◽  
Secondary Electron Emission ◽  
Small Angle Scattering ◽  
Reciprocal Space ◽  
Two Dimensional ◽  
Angle Scattering ◽  
Scanning Electron

An attempt has been made to combine small-angle scattering of X-rays or neutrons with scanning electron microscopy in reciprocal space, in order to establish a structural analysis method covering a wide range of sizes from micro- to macro-scales. A system with a binary contrast, in which scattering objects with a homogeneous density are dispersed in vacuum (or air), is considered. A topological surface image, detected by secondary electron emission, is converted by means of a Fourier transform into a two-dimensional scattering amplitude in reciprocal space. The method was first tested by studying a dilute system of monodisperse SiO2 particles, with respect to calibrations for brightness inversion, noise reduction and two-dimensional Fourier transform, to obtain a scattering amplitude that agrees well with the analytical amplitude for a spherical particle. Secondly, the microstructure of a carbon-supported Pt catalyst for polymer electrolyte fuel cell applications was examined with the combined method, covering length scales from 10 µm down to nanometres. After two-dimensional Fourier transformation, the secondary electron emission images with low magnification are able to overcome the limitation of the minimum wavenumber (q min) detectable by ultra-small-angle scattering.

Realization of two-dimensional anomalous small-angle scattering of Al alloys at the K absorption edge of Al

2016 ◽  
Vol 49 (5) ◽  
pp. 1803-1805 ◽  
Author(s):  
Hiroshi Okuda ◽  
Rei Sakohata ◽  
Yoshinori Kitajima ◽  
Yusuke Tamenori
Keyword(s):  
Absorption Edge ◽  
Small Angle ◽  
Dynamic Range ◽  
Two Dimensional ◽  
X Ray Scattering ◽  
Angle Scattering ◽  
Ccd Detector ◽  
Phosphor Plate ◽  
Alumina Nanopowder ◽  
Zn Alloy

Two-dimensional anomalous small-angle X-ray scattering (ASAXS) measurements at the K absorption edge of Al have been successfully performed. Contrast change below the absorption edge was detected with the use of a CCD detector. The change of ASAXS intensities near the edge for alumina nanopowder and that for Guinier–Preston zones in an Al–Zn alloy were explained by the anomalous dispersion of Al. The present results showed that two-dimensional SAXS measurements with a dynamic range extended to show Porod's law have been achieved for photon energies of about 1.5 keV with the use of a CCD detector optically coupled with a P43 phosphor plate.

SASET: a program for series analysis of small-angle scattering data

2013 ◽  
Vol 46 (4) ◽  
pp. 1187-1195 ◽  
Author(s):  
Michael Muthig ◽  
Sylvain Prévost ◽  
Reinhold Orglmeister ◽  
Michael Gradzielski
Keyword(s):  
Small Angle ◽  
Evaluation Process ◽  
Small Angle Scattering ◽  
Scattering Data ◽  
Data Series ◽  
Two Dimensional ◽  
Evaluation Tool ◽  
Fitting Procedure ◽  
Angle Scattering ◽  
Anisotropy Measurement

This article presents a new program that allows highly automatized analyses of series of, especially, anisotropic two-dimensional neutron and X-ray small-angle scattering data as well as one-dimensional data series. The main aim of this work was to reduce the effort of the analysis of complex scattering systems, which remains an essential burden in the evaluation process of complex systems. The program is built in a modular manner to support a stepwise analysis of small-angle scattering data. For example, from a two-dimensional data series, features such as anisotropy or changes of the preferred scattering direction or intensities along the radial or azimuthal directions as well as along the series axis (e.g. time axis) can quickly be extracted. Different anisotropy measurement methods are available, which are described herein. In a second step, physical scattering models can be fitted to the extracted data. More complex models can be easily added. The fitting procedure can be applied with nearly every possible constraint and works automatically on whole scattering data series. Furthermore, simultaneous fitting can be used to analyze coupled series, and parallel working methods are implemented to speed up the code execution. Finally, results can be easily visualized. The name of the program isSASET, which is an acronym standing for small-angle scattering evaluation tool.SASETis based on MATLAB.

Electron and phonon scattering II. Thermoelectricity in rubidium, caesium and alloys at very low temperatures

1963 ◽  
Vol 274 (1357) ◽  
pp. 154-162 ◽  
Keyword(s):  
Fermi Surface ◽  
Electron Scattering ◽  
Small Angle ◽  
Low Temperatures ◽  
Phonon Scattering ◽  
Large Angle ◽  
Phonon Drag ◽  
Diffusion Term ◽  
Angle Scattering ◽  
The Difference

Following earlier measurements on pure potassium and alloys, we have now made a corresponding study at very low temperatures of thermoelectricity in rubidium, caesium, and their alloys with each other and with potassium. The results have proved in accord with our interpretation of the earlier work, and we discuss the trends observed in both the ‘electron diffusion’ and ‘phonon-drag’ contributions to the absolute thermoelectric power. Both contributions as observed in these metals are consistent with a larger distortion in the Fermi surface of caesium than in those of potassium or rubidium. It appears that the changes in the thermoelectric diffusion term can be attributed consistently to the difference arising from large-angle and small angle scattering. It is supposed that in turn these types of electron scattering arise from the presence of homovalent and heterovalentim purity centres.

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