Quantification in Elemental DIstributions of Light Atoms by EEL Image Analysis in Biological Sections

1982 ◽  
Vol 40 ◽  
pp. 420-423
Author(s):  
F. P. Ottensmeyer
Keyword(s):  
Elemental Content ◽  
Single Element ◽  
X Ray ◽  
Transmission Electron ◽  
Spectral Evaluation ◽  
Scanning Transmission ◽  
Spectrum Characteristic ◽  
Electron Microscopes ◽  
Electron Energy Loss ◽  
Magnetic Electron

Microanalysis by electron energy loss spectroscopy has gained momentum in the last few years with the utilization of more and more magnetic electron spectrometers coupled to dedicated or hybrid scanning transmission electron microscopes. Two approaches to analysis are the spectral evaluation of a single spot and the mapping of a single element over the entire image. In the first method, as in x-ray microanalysis, a finely focused electron beam is placed on a small area of the specimen. The impinging electrons traversing this spot subsequently provide a spectrum characteristic of the elemental content of the area.

scholarly journals Materials science applications of a 120kV FEG TEM/STEM: Triskaidekaphilia

1991 ◽  
Vol 49 ◽  
pp. 698-699
Author(s):  
J. Bentley ◽  
A. T. Fisher ◽  
E. A. Kenik ◽  
Z. L. Wang
Keyword(s):  
Electron Microscope ◽  
Materials Science ◽  
X Ray ◽  
Transmission Electron ◽  
Analytical Electron ◽  
Analytical Electron Microscope ◽  
Scanning Transmission ◽  
Potential Impact ◽  
Electron Microscopes ◽  
Electron Energy Loss

The introduction by several manufacturers of 200kV transmission electron microscopes (TEM) equipped with field emission guns affords the opportunity to assess their potential impact on materials science by examining applications of similar 100-120kV instruments that have been in use for more than a decade. This summary is based on results from a Philips EM400T/FEG configured as an analytical electron microscope (AEM) with a 6585 scanning transmission (STEM) unit, ED AX 9100/70 or 9900 energy dispersive X-ray spectroscopy (EDS) systems, and Gatan 607 serial- or 666 parallel-detection electron energy-loss spectrometers (EELS). Examples in four areas that illustrate applications that are impossible or so difficult as to be impracticable with conventional thermionic electron guns are described below.

High Spatial Resolution Compositional Analysis at Interfaces

1980 ◽  
Vol 38 ◽  
pp. 356-359
Author(s):  
John B. Vander Sande ◽  
Thomas F. Kelly ◽  
Douglas Imeson
Keyword(s):  
Electron Microscope ◽  
High Spatial Resolution ◽  
Compositional Analysis ◽  
Scanning Transmission Electron Microscope ◽  
Thin Specimen ◽  
X Ray ◽  
Volume Of Interest ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Energy Loss

In the scanning transmission electron microscope (STEM) a fine probe of electrons is scanned across the thin specimen, or the probe is stationarily placed on a volume of interest, and various products of the electron-specimen interaction are then collected and used for image formation or microanalysis. The microanalysis modes usually employed in STEM include, but are not restricted to, energy dispersive X-ray analysis, electron energy loss spectroscopy, and microdiffraction.

Energy-dispersive x-ray detectors for analytical electron microscopy

1991 ◽  
Vol 49 ◽  
pp. 986-987
Author(s):  
L. E. Thomas
Keyword(s):  
Collection Efficiency ◽  
Analytical Electron Microscopy ◽  
Energy Dispersive ◽  
Detector Performance ◽  
X Ray ◽  
Performance Improvements ◽  
Transmission Electron ◽  
Analytical Electron ◽  
Scanning Transmission ◽  
Electron Microscopes

Continuing evolution of energy-dispersive x-ray spectrometer (EDS) systems has greatly advanced x-ray detector performance in analytical electron microscopes. The latest detectors offer improved energy resolution, count rate performance, geometrical collection efficiency, durability, and efficiency for light and heavy elements. Innovative detector designs for transmission and scanning transmission electron microscopes (TEM/STEMs) include such features as liquid-nitrogen-free operation, in situ de-icing of the detector crystal, user cleanable windows, demountable windows, ultrahigh vacuum compatibility (including adaptations to allow microscope bakeouts without removing the detector), beam damage protection, and microscope interfaces with optimized collection geometries. Divergent design philosophies have produced a variety of systems with specialized features, and users may face hard choices in selecting the best detector for the job. The aim of this paper is to review the current state of EDS detector development and the importance of the performance improvements to TEM/STEM users.

scholarly journals New capabilities for `colouring in' the chemistry of crystal defects atom-by-atom

2014 ◽  
Vol 70 (6) ◽  
pp. 521-523
Author(s):  
Sarah J. Haigh
Keyword(s):  
High Resolution ◽  
High Efficiency ◽  
Crystal Defects ◽  
Energy Dispersive ◽  
Acta Cryst ◽  
X Ray ◽  
Elemental Imaging ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electron Microscopes

The latest generation of scanning transmission electron microscopes equipped with high-efficiency energy-dispersive X-ray detectors are breaking new ground with respect to high-resolution elemental imaging of materials. In this issue, Paulauskaset al.[Acta Cryst.(2014), A70, 524–531] demonstrate impressive results when applying this technique to improve understanding of CdTe dislocation structures.

scholarly journals Sodium-Vanadium Bronze Na9V14O35: An Electrode Material for Na-Ion Batteries

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 86
Author(s):  
Maria A. Kirsanova ◽  
Alexey S. Akmaev ◽  
Mikhail V. Gorbunov ◽  
Daria Mikhailova ◽  
Artem M. Abakumov
Keyword(s):  
Negative Electrode ◽  
X Ray Diffraction ◽  
Conversion Reaction ◽  
X Ray ◽  
Electroactive Material ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Electrochemical Capacity ◽  
Silica Ampoule ◽  
Electron Energy Loss

Na9V14O35 (η-NaxV2O5) has been synthesized via solid-state reaction in an evacuated sealed silica ampoule and tested as electroactive material for Na-ion batteries. According to powder X-ray diffraction, electron diffraction and atomic resolution scanning transmission electron microscopy, Na9V14O35 adopts a monoclinic structure consisting of layers of corner- and edge-sharing VO5 tetragonal pyramids and VO4 tetrahedra with Na cations positioned between the layers, and can be considered as sodium vanadium(IV,V) oxovanadate Na9V104.1+O19(V5+O4)4. Behavior of Na9V14O35 as a positive and negative electrode in Na half-cells was investigated by galvanostatic cycling against metallic Na, synchrotron powder X-ray diffraction and electron energy loss spectroscopy. Being charged to 4.6 V vs. Na+/Na, almost 3 Na can be extracted per Na9V14O35 formula, resulting in electrochemical capacity of ~60 mAh g−1. Upon discharge below 1 V, Na9V14O35 uptakes sodium up to Na:V = 1:1 ratio that is accompanied by drastic elongation of the separation between the layers of the VO4 tetrahedra and VO5 tetragonal pyramids and volume increase of about 31%. Below 0.25 V, the ordered layered Na9V14O35 structure transforms into a rock-salt type disordered structure and ultimately into amorphous products of a conversion reaction at 0.1 V. The discharge capacity of 490 mAh g−1 delivered at first cycle due to the conversion reaction fades with the number of charge-discharge cycles.

Efforts to improve the quantification of EDX analyses, particularly for the light elements

1991 ◽  
Vol 49 ◽  
pp. 716-717
Author(s):  
G. L'Espérance
Keyword(s):  
Scanning Transmission Electron Microscope ◽  
Light Elements ◽  
Thin Specimen ◽  
Complementary Technique ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Edx Analyses ◽  
Electron Energy Loss ◽  
Detection And Quantification

The attachment of a Si(Li) energy dispersive X-ray (EDX) detector to a (scanning) transmission electron microscope ((S)TEM) is widely used to carry out quantitative determinations of elemental composition of a localized region of a thin specimen. Although the principles of the technique first proposed by Cliff and Lorimer have been established for some time, there are still a large number of sources of errors. In addition, EDX analyses have been generally restricted until recently to elements with an atomic number (Z) larger than that of sodium (Z > 10) so that electron energy loss spectroscopy (EELS) was the preferred technique for the detection of light elements in an AEM. The relatively recent advent of ultra-thin window (UTW) detectors has offered an alternative (and often complementary) technique to EELS for the analysis of light elements with additional difficulties in the detection and quantification. This paper presents some results of investigations made to improve the quantification of EDX data. Particular attention is given to the detection and quantification of data from light elements on a routine and reproducible basis.

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