On the problem of filtered images in chemical analysis

1978 ◽  
Vol 36 (1) ◽  
pp. 538-539
Author(s):  
G. Zanchi ◽  
J. Sevely ◽  
B. Jouffrey
Keyword(s):  
Chemical Analysis ◽  
Energy Loss ◽  
High Spatial Resolution ◽  
Energy Losses ◽  
List Type ◽  
Characteristic Energy ◽  
X Ray ◽  
Energy Filtering ◽  
Imaging Properties ◽  
Loss Range

As was proposed in several recent review papers (for instance 1-3) it is interesting to use electron energy losses corresponding to inner shell excitations by incident electrons to perform chemical analysis. One of the main advantages of the inner shell excitation spectroscopy (ISES) is that it is essentially available for light elements, contrary to characteristic X ray emission spectroscopy.Two methods can be used :- energy analysis : energy loss spectra are obtained from selected projected area of the sample and elemental characteristic energy losses are detected;- image energy filtering : images are formed by selecting electrons in an energy loss range which contains a characteristic energy loss. They show a map of the distribution of a given element in the object with a high spatial resolution.Combining these two methods is quite essential to perform chemical analysis. Such studies can be achieved in CTEM by means of an energy filtering system preserving the imaging properties of the microscope.

Energy-filtered imaging in biological intermediate voltage TEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1570-1571
Author(s):  
A.J. Gubbens ◽  
O.L. Krivanek
Keyword(s):  
Spatial Distribution ◽  
Elastic Scattering ◽  
Energy Loss ◽  
Inelastic Scattering ◽  
Chromatic Aberration ◽  
Biological Information ◽  
Energy Losses ◽  
Objective Lens ◽  
Characteristic Energy ◽  
Energy Filtering

In biological specimens of 150 nm and greater, inelastic scattering typically surpasses elastic scattering in magnitude. Because of the chromatic aberration of the objective lens of a TEM, the inelastically scattered electrons are focused differently, resulting in a loss of contrast in an ordinary TEM. With energy filtering, however, the inelastically scattered electrons can be prevented from contributing to the image, resulting in substantial recovery of contrast. In very thick specimens (1-5 μm), an energy filter can be used to select electrons of a particular energy loss, and an image with usable contrast can be formed. Further, by imaging only with electrons that have experienced characteristic energy losses, information can be obtained about the spatial distribution of various elements in the sample.Because of presently available instrumentation, energy filtered biological TEM has so far only been performed with TEMs of primary energies of 120 keV and lower. In this paper, we demonstrate the feasibilty of obtaining interesting biological information with a newly developed imaging filter designed for operation at up to 400 kV.

Electron spectroscopic diffraction at (111) silicon foils

1989 ◽  
Vol 47 ◽  
pp. 382-383
Author(s):  
L. Reimer ◽  
I. Fromm
Keyword(s):  
Energy Loss ◽  
Phonon Scattering ◽  
Bloch Wave ◽  
Foil Thickness ◽  
Energy Losses ◽  
Energy Filtering ◽  
Thin Foils ◽  
Kikuchi Lines ◽  
Lattice Planes ◽  
Electron Spectroscopic Diffraction

An electron diffraction pattern (EDP) consists of an overlap of patterns of all energy losses in the electron energy-loss spectrum (EELS). Electron spectroscopic diffraction (ESD) in an energy filtering electron microscope (EFEM) allows to separate the contributions of different energy losses to the unfiltered diagram observed in conventional TEM. We report about diffraction experiments with a Zeiss EM902 on (111) silicon foils which show how the EDP of single-crystal foils changes with increasing energy loss and foil thickness. An EDP normally contains the Bragg spots, diffuse streaks by electron-phonon scattering, excess and defect Kikuchi lines when the number of electrons striking the lattice planes is different from opposite sites, a system of excess (bright) Kikuchi bands with an intensity proportional to the probability ψψ⋆ of the Bloch wave field at the nuclei, and defect Ki-kuchi bands when the number of diffusely scattered electrons is equal on both sides of the lattice plane and the intensity becomes proportional to ΣIg.EDPs of thin foils show an increase of contrast of the Bragg spots and the thermal diffuse streaks when comparing an unfiltered (Fig.1a) and zero-loss filtered EDP (Fig.1b). Because the streaks are caused by elastic scattering, they can not be ob served with the plasmon loss (Fig.1c). Bragg spots are also observed at higher energy losses because all delocalized inelastic scattering processes with energy losses less a few hundred eV show intraband transitions which preserve the type of excited Bloch waves.

scholarly journals Interface-Induced Plasmon Nonhomogeneity in Nanostructured Metal-Dielectric Planar Metamaterial

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
A. I. Kovalev ◽  
D. L. Wainstein ◽  
A. Yu. Rashkovskiy ◽  
R. Gago ◽  
F. Soldera ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Electronic States ◽  
Energy Losses ◽  
Critical Layer Thickness ◽  
Characteristic Energy ◽  
X Ray ◽  
Nanostructured Metal

Transformations of the electronic structure in thin silver layers in metal-dielectric (TiAlN/Ag) multilayer nanocomposite were investigated by a set of electron spectroscopy techniques. Localization of the electronic states in the valence band and reduction of electron concentration in the conduction band was observed. This led to decreasing metallic properties of silver in the thin films. A critical layer thickness of 23.5 nm associated with the development of quantum effects was determined by X-ray photoelectron spectroscopy. Scanning Auger electron microscopy of characteristic energy losses provided images of plasmon localization in the Ag layers. The nonuniformity of plasmon intensities distribution near the metal-nitride interfaces was assessed experimentally.

Element analysis with the imaging electron energy loss spectrometer of the zeiss EM 902

1986 ◽  
Vol 44 ◽  
pp. 600-601
Author(s):  
J. Bihr ◽  
A. Rilk ◽  
W.I. Miller
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Spectroscopic Imaging ◽  
Element Analysis ◽  
X Ray ◽  
Electron Energy Loss Spectrometer ◽  
Elemental Maps ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra ◽  
Loss Range

An imaging electron energy loss spectrometer can be used to produce elemental maps with highest spatial resolution by Electron Spectroscopic Imaging (ESI). Simultaneously, electron energy loss spectra (EELS) can also be recorded. It is therefore simple to combine morphological examinations with the analytical method of electron energy loss spetroscopy (Figs. 2, 3)The electron energy loss spectrometer of the EM 902, used in combination with a suitable electron detector (Fig. 1), provides the possibility of recording electron energy loss spectra over an energy loss range from 0 to 2000 eV. In this way, all elements of the periodic system can be detected via their K, L, M, N or O absorption edges (Fig. 5). Unlike X-ray microanalysis, this technique is especially suitable for detecting light and medium-heavy elements which are of special significance in biological and medical research.

Applications of Monte Carlo Simulation of Electron Scattering to Quantitative X-Ray Microanalyses

2001 ◽  
Vol 7 (S2) ◽  
pp. 690-691
Author(s):  
Kenji Murata ◽  
Masaaki Yasuda ◽  
Syunji Yamauchi
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Elastic Scattering ◽  
Energy Loss ◽  
Cross Section ◽  
Electron Scattering ◽  
List Type ◽  
Discrete Energy ◽  
X Ray ◽  
Loss Process

Monte Carlo simulation of electron scattering has been widely used in various fields such as microanalysis, microscopy and microlithography. Various simulation models have been reported so far. in applications to quantitative x-ray microanalysis the accuracy of the model has been significantly improved by introducing the Mott cross section. However, in the analyses at low energies of an electron beam or at energies near the x-ray excitation energy, the simulation accuracy becomes worse. This is probably because the discrete energy loss process is not incorporated into the simulation model. to improve this default, we developed the model which includes the discrete energy loss process[l]. The outline of the model is described in the following.1)Elastic scatteringWe used the Mott cross section. The Mott cross sections for Al, Cu, Ag and Au elements are calculated at various energies. From this data base we obtain the differential elastic scattering cross section and the total elastic cross section for arbitarary elements and energies by using the interporation or the extrapolation.

Correlative electron and X-ray microscopy: probing chemistry and bonding with high spatial resolution

Nanoscale ◽  
2015 ◽  
Vol 7 (5) ◽  
pp. 1534-1548 ◽  
Author(s):  
Angela E. Goode ◽  
Alexandra E. Porter ◽  
Mary P. Ryan ◽  
David W. McComb
Keyword(s):  
Electron Microscope ◽  
Energy Loss ◽  
Transmission Electron Microscope ◽  
High Spatial Resolution ◽  
Scanning Transmission Electron Microscope ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Energy Loss ◽  
X Ray Absorption

Benefits and challenges of correlative spectroscopy: electron energy-loss spectroscopy in the scanning transmission electron microscope (STEM-EELS) and X-ray absorption spectroscopy in the scanning transmission X-ray microscope (STXM-XAS).

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