Quantitative Electron Energy Loss Mapping

1985 ◽  
Vol 43 ◽  
pp. 404-405
Author(s):  
R.D. Leapman ◽  
C.R. Swyt
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Elemental Concentration ◽  
Core Loss ◽  
Elemental Distribution ◽  
Electron Energy Loss

The intensity of a characteristic electron energy loss spectroscopy (EELS) image does not, in general, directly reflect the elemental concentration. In fact, the raw core loss image can give a misleading impression of the elemental distribution. This is because the measured core edge signal depends on the amount of plural scattering which can vary significantly from region to region in a sample. Here, we show how the method for quantifying spectra due to Egerton et al. can be extended to maps.

Some problems and solutions in electron energy loss spectroscopy of cryosections

1993 ◽  
Vol 51 ◽  
pp. 566-567
Author(s):  
Zhifeng Shao ◽  
Ruoya Ho ◽  
Andrew P. Somlyo
Keyword(s):  
High Resolution ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Biological Research ◽  
Specimen Thickness ◽  
Elemental Distribution ◽  
Electron Dose ◽  
Simple Assumption ◽  
Electron Energy Loss

Electron energy loss spectroscopy (EELS) has been a powerful tool for high resolution studies of elemental distribution, as well as electronic structure, in thin samples. Its foundation for biological research has been laid out nearly two decades ago, and in the subsequent years it has been subjected to rigorous, but by no means extensive research. In particular, some problems unique to EELS of biological samples, have not been fully resolved. In this article we present a brief summary of recent methodological developments, related to biological applications of EELS, in our laboratory. The main purpose of this work was to maximize the signal to noise ratio (S/N) for trace elemental analysis at a minimum dose, in order to reduce the electron dose and/or time required for the acquisition of high resolution elemental maps of radiation sensitive biological materials.Based on the simple assumption of Poisson distribution of independently scattered electrons, it had been generally assumed that the optimum specimen thickness, at which the S/N is a maximum, must be the total inelastic mean free path of the beam electron in the sample.

scholarly journals Image Formation Based on Atomic Resolution Core-loss Electron Energy Loss Spectroscopy

2006 ◽  
Vol 12 (S02) ◽  
pp. 1138-1139
Author(s):  
MP Oxley ◽  
K van Benthem ◽  
M Varela ◽  
SD Findlay ◽  
LJ Allen ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Core Loss ◽  
Image Formation ◽  
Atomic Resolution ◽  
Electron Energy Loss

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2006

Empirical Identification of Uranium Oxides and Fluorides Using Electron Energy-loss Spectroscopy in the Transmission Electron Microscope

1999 ◽  
Vol 5 (6) ◽  
pp. 437-444 ◽  
Author(s):  
Stephen B. Rice ◽  
Hazel H. Bales ◽  
John R. Roth ◽  
Allen L. Whiteside
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Contaminated Soils ◽  
Core Loss ◽  
Uranium Oxides ◽  
Low Loss ◽  
Electron Dose ◽  
Core Losses ◽  
Electron Energy Loss

Abstract: A set of uranium compound particles relevant to contaminated soils and other environmental concerns surrounding uranium bioavailability were studied by electron energy-loss spectroscopy (EELS). Core-loss EELS results suggest that uranium 4+ compounds have an energy loss resolvable from 6+ compounds. Shoulders on the uranium O4,5 edge further distinguish UO2 from UF4. Low-loss characteristics distinguish carbon-free uranium oxide specimens on holey substrates. In the presence of carbon, correction techniques must be applied. Uranium oxides, fluorides, and minerals show a tendency toward reduction of uranium toward 4+ under the beam. The electron dose required to achieve the transformation from 6+ to 4+ is more severe than that usually required to obtain satisfactory spectra, but the possibility for reduction should be considered. The conditions for low-loss analysis need not be as vigorous as those for core losses, and can be done without altering the valence of most oxides.

scholarly journals Rapid Simulation of Elemental Maps in Core-Loss Electron Energy Loss Spectroscopy

2019 ◽  
Vol 25 (S2) ◽  
pp. 574-575
Author(s):  
H. G. Brown ◽  
S. D. Findlay ◽  
L. J. Allen ◽  
J. Ciston ◽  
C. Ophus
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Core Loss ◽  
Elemental Maps ◽  
Electron Energy Loss

Theory of Electron Energy Loss Spectroscopy and its Application to Threading Edge Dislocations in GaN

2001 ◽  
Vol 693 ◽  
Author(s):  
C. J. Fall ◽  
R. Jones ◽  
P. R. Briddon ◽  
A. T. Blumenau ◽  
T. Frauenheim ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Core Loss ◽  
Extended Defects ◽  
Low Loss ◽  
Defect Accumulation ◽  
Edge Dislocations ◽  
Electron Energy Loss

AbstractThe electronic structure of dislocations in GaN is controversial. Several experimental techniques such as carrier mobility studies and cathodoluminescence experiments have indicated that dislocations are charged while theoretical studies point to intrinsic states and/or point defect accumulation along the core as a source of electrical activity. Electron Energy Loss Spectroscopy (EELS) studies have the ability to probe the electronic structure of extended defects. Here we report rst principles calculations of the EELS spectrum applied to edge dislocations in GaN. It is found that the electrostatic potential at N atoms in the vicinity of the dislocation varies by the order of a volt and casts doubt on any simple interpretation of core loss spectroscopy. On the other hand, low loss spectroscopy leads directly to detailed information about any gap states. The low loss spectrum obtained by the theory is in good agreement with recent experimental work and indicates that threading dislocations in p-type GaN possess acceptor levels in the upper half of the gap.

Probing the Chemical Structure in Diamond-Based Materials Using Combined Low-Loss and Core-Loss Electron Energy-Loss spectroscopy

2014 ◽  
Vol 20 (3) ◽  
pp. 779-783 ◽  
Author(s):  
Paolo Longo ◽  
Ray D. Twesten ◽  
Jaco Olivier
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Core Loss ◽  
Amorphous Region ◽  
Low Loss ◽  
Plasmon Energy ◽  
Carbon Structure ◽  
Experimental Conditions ◽  
Electron Energy Loss

AbstractWe report the analysis of the changes in local carbon structure and chemistry caused by the self-implantation of carbon into diamond via electron energy-loss spectroscopy (EELS) plasmon energy shifts and core-edge fine structure fingerprinting. These two very different EELS energy and intensity ranges of the spectrum can be acquired under identical experimental conditions and nearly simultaneously using specially designed deflectors and energy offset devices known as “DualEELS.” In this way, it is possible to take full advantage of the unique and complementary information that is present in the low- and core-loss regions of the EELS spectrum. We find that self-implanted carbon under the implantation conditions used for the material investigated in this paper creates an amorphous region with significant sp2 content that varies across the interface.

Characterization of Some 3d Transition Metal Oxides through Core Loss Electron Energy Loss Spectroscopy

1980 ◽  
Vol 38 ◽  
pp. 122-123
Author(s):  
L. A. Grunes
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Transition Metal Oxides ◽  
Core Loss ◽  
The Core ◽  
Medium Resolution ◽  
Core Losses ◽  
Electron Energy Loss

Electron Energy Loss Spectroscopy (EELS) is a useful technique for chemical microanalysis in the electron microscope. In particular, medium resolution (˜leV) measurements of core losses involving ionization of the tightly bound inner shell electrons reveal fine structure which identify both the core atom and the neighboring chemical environment. The transition metals of the third period possess narrow partly filled d-bands which give rise to striking magnetic and electronic properties of technological importance.

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