scholarly journals Elemental Mapping of Labeled Biological Specimens at Intermediate Energy Loss in an Energy-Filtered TEM acquired using a Direct Detection Device

2020 ◽  
Author(s):  
Ranjan Ramachandra ◽  
Mason R. Mackey ◽  
Junru Hu ◽  
Steven T. Peltier ◽  
Nguyen-Huu Xuong ◽  
...  
Keyword(s):  
Energy Loss ◽  
Lower Energy ◽  
Direct Detection ◽  
Core Loss ◽  
Intermediate Energy ◽  
High Signal ◽  
Experimental Conditions ◽  
High Loss ◽  
The Core ◽  
Elemental Maps

ABSTRACTThe multi-color or single-color EM that was developed previously, by the pseudo-colored overlay of the core-loss or high-loss EFTEM elemental map/s of the lanthanide onto the conventional image, the lanthanide chelates conjugated to diaminobenzidine being sequentially deposited as a result of selective oxidization by orthogonal photosensitizers / peroxidases. The synthesis of the new second generation lanthanide DABs, which contains 4 times more lanthanide per DAB, gives significant signal amplification and enabling collection of elemental maps at much lower energy-loss regions more favorable. Under the same experimental conditions, acquiring EFTEM elemental maps for the lanthanides at the lower energy-loss of N4,5 edge instead of the core-loss M4,5 edge, provides ~4x increase in signal-to-noise and ~2x increase in resolution. The higher signal at the N4,5 edge, also allows for more sophisticated technique of EFTEM spectrum Image for the acquisition of elemental maps with very high signal fidelity.

Nickel L2,3 core energy loss studies in NiSi2

1992 ◽  
Vol 50 (2) ◽  
pp. 1358-1359
Author(s):  
Kaikee Wong ◽  
John Silcox
Keyword(s):  
Energy Loss ◽  
Signal To Noise Ratio ◽  
Core Loss ◽  
Spot Size ◽  
High Signal ◽  
Signal To Noise ◽  
The Core ◽  
Dipole Excitation ◽  
Core Energy ◽  
Initial States

The L2 and L3 edges in EELS spectra of 3d transition metals arise primarily from dipole excitation of the 2p1/2 and 2p3/2 electrons to unfilled 3d states. Since the initial states have narrow energy widths, the L2,3 edges reflect the conduction band density of states (DOS) with d character. By comparing the Ni L2,3 edges in NiSi2 to those in pure Ni, the bonding between Ni and Si can be studied.Experiments were carried out in an UHV HB501A STEM operating at 100 keV with a serial EELS spectrometer. The spot size and the current were estimated to be 5 Å and 0.1 nA respectively. Both the convergence and the detector angles were about 11 mrad. The spectra were recorded in steps of 0.25 eV for Ni and 0.5 eV for NiSi2. Long dwell times were necessary to achieve high signal to noise ratio in the core loss spectra and typically 5 sec per energy step was used.

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

The Effect of Energy Loss on Lattice Fringe Images of Dysprosium Oxide—

1977 ◽  
Vol 35 ◽  
pp. 242-243
Author(s):  
A. J. Craven ◽  
C. Colliex
Keyword(s):  
Energy Loss ◽  
Core Loss ◽  
Energy Window ◽  
Plasmon Excitation ◽  
Dysprosium Oxide ◽  
The Core ◽  
Lattice Fringe ◽  
Type C ◽  
Lower Contrast

Energy filtered 7.5 Å lattice fringes from type C crystalline dysprosium oxide, (Dy203), have been recorded with a V.G. Microscopes HB5 STEM. A spectrum from the specimen is shown in fig. 1. The principal features are a collective 'plasmon' excitation (P) at 15.7 eV and a 5P core-loss (C) at 37.2 eV (1). Fig. 2a, b, c, d are lattice fringe images recorded in 100 seconds with an objective (i.e. probe) semi-angle of 8 mrad and a collector semi-angle of 1 mrad. Fig. 2a is unfiltered and fig. 2b, c, d are filtered with an 8 eV energy window centred on 0 eV, 16 eV and 37 eV respectively. The lattice fringes persist in the images formed with loss electrons, but their visibility is much reduced because of lower contrast and higher noise. The contrast was measured from line traces and for one set of results was 0.17 ± 0.02 for the unfiltered image, 0.27 ± 0.02 for the zero loss image, 0. 21.± 0.02 for the plasmon image and 0.27 ± 0.03 for the core loss (contrast = 2(Imax - Imin)/(Imax + Imin)).

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.

Log-polynomial background subtraction in energy-filtered TEM

1996 ◽  
Vol 54 ◽  
pp. 544-545 ◽  
Author(s):  
N. D. Evans ◽  
J. Bentley
Keyword(s):  
Energy Loss ◽  
Background Subtraction ◽  
Core Loss ◽  
Power Relation ◽  
Inverse Power ◽  
Transmission Electron ◽  
Electron Energy Loss Spectrometry ◽  
Least Squares Fit ◽  
Integrated Intensities ◽  
Elemental Maps

An inverse power relation is widely used to model the background under inner shell ionization edges in both electron energy-loss spectrometry (EELS) and energy-filtered transmission electron microscopy (EFTEM). Proper background subtraction is necessary to obtain correct core-loss integrated intensities in EELS or elemental maps in EFTEM. However, the empirical inverse power relation often does not accurately model the background when losses at slightly lower energies interfere with the edge of interest, or in general, when energy losses are less than ∼200 eV. In such cases, the background of EELS spectra has been successfully fitted as a linear least-squares fit to a polynomial, usually a quadratic of the form: log(I) = A + BX + CX2, where I = intensity and X = log(energy loss). In the present study, this alternative background model, the “log-polynomial,” has been applied to pre-edge images for background subtraction from post-edge energy-filtered images.

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.

scholarly journals Improving Signal to Noise in Labeled Biological Specimens Using Energy-Filtered TEM of Sections with a Drift Correction Strategy and a Direct Detection Device

2014 ◽  
Vol 20 (3) ◽  
pp. 706-714 ◽  
Author(s):  
Ranjan Ramachandra ◽  
James C. Bouwer ◽  
Mason R. Mackey ◽  
Eric Bushong ◽  
Steven T. Peltier ◽  
...  
Keyword(s):  
Direct Detection ◽  
Core Loss ◽  
Short Exposure ◽  
Signal To Noise ◽  
Charge Coupled Device ◽  
Transmission Electron ◽  
Noise Image ◽  
Spatially Distributed ◽  
Microscopy Techniques ◽  
Elemental Maps

AbstractEnergy filtered transmission electron microscopy techniques are regularly used to build elemental maps of spatially distributed nanoparticles in materials and biological specimens. When working with thick biological sections, electron energy loss spectroscopy techniques involving core-loss electrons often require exposures exceeding several minutes to provide sufficient signal to noise. Image quality with these long exposures is often compromised by specimen drift, which results in blurring and reduced resolution. To mitigate drift artifacts, a series of short exposure images can be acquired, aligned, and merged to form a single image. For samples where the target elements have extremely low signal yields, the use of charge coupled device (CCD)-based detectors for this purpose can be problematic. At short acquisition times, the images produced by CCDs can be noisy and may contain fixed pattern artifacts that impact subsequent correlative alignment. Here we report on the use of direct electron detection devices (DDD’s) to increase the signal to noise as compared with CCD’s. A 3× improvement in signal is reported with a DDD versus a comparably formatted CCD, with equivalent dose on each detector. With the fast rolling-readout design of the DDD, the duty cycle provides a major benefit, as there is no dead time between successive frames.

The Thickness Dependence of Energy Loss Spectra

1982 ◽  
Vol 40 ◽  
pp. 486-487
Author(s):  
M. Sarikaya ◽  
P. Rez
Keyword(s):  
Energy Loss ◽  
Multiple Scattering ◽  
Core Loss ◽  
Single Scattering ◽  
Low Loss ◽  
High Loss ◽  
Loss Analysis ◽  
Scattering Spectrum ◽  
Exact Procedure ◽  
Quantitative Analyses

One factor limiting energy loss analysis is the effect of multiple scattering on core loss edge shapes. Multiple scattering distorts fine structures, leads to incorrect quantitative analyses and even affects analysis of extended fine structure (EXELFS). Two procedures for extracting the single scattering spectrum from a spectrum showing the effects of multiple scattering have been proposed. Johnson and Spence derive the single scattering profile by taking the logarithm of the fourier transformed spectrum. If all scattering angles are accepted by the spectrometer this is an exact procedure. Leapman and Swyt have had some success assuming that multiple scattering imposes low loss structure on the high loss part of the spectrum. It is of interest to know how stable these procedures are with thickness and whether the logarithmic deconvolution can be used in thicker specimens than the method described by Leapman and Swyt.

Energy loss extreme — near-edge and pre-edge structure

1988 ◽  
Vol 46 ◽  
pp. 498-499
Author(s):  
P.E. Batson
Keyword(s):  
Fine Structure ◽  
High Resolution ◽  
Energy Loss ◽  
Electronic Materials ◽  
Core Loss ◽  
Edge Structure ◽  
The Core ◽  
Signal Collection ◽  
Spectrometer System ◽  
Direct Inter

During the past several years we have begun to understand many features of the core loss excitations including absolute crosssections, extended fine structure, (EXELFS) and near edge fine structure. (ELNES) In electronic materials near interfaces or defects, we expect the valence and conduction bands to be modified by the existence of isolated resonances, broadening of the band edges, or a completely filled gap region. These electronic changes have been observed with high resolution EELS in the low energy loss region (0-3eV) where direct inter-band transitions are likely. The present work is aimed at determining if pre-edge structure near the core loss scattering may reflect local changes in the electronic structure as well. There are two major experimental difficulties: 1) the necessary energy resolution is of order 0.1-0.3eV in order to define the shape of the core edge; and 2) the energy differential scattering cross section is small (of order 10-23cm2eV-1). At IBM I have addressed these problems by constructing a high resolution energy loss spectrometer system with parallel recording to allow signal collection in reasonable times.

A Practical Method for Removing Plural Scattering from Core Edges in EELS

1981 ◽  
Vol 39 ◽  
pp. 196-197
Author(s):  
R.D. Leapman ◽  
C.R. Swyt
Keyword(s):  
Core Loss ◽  
Practical Method ◽  
Electron Excitation ◽  
Single Scattering ◽  
Low Loss ◽  
High Loss ◽  
The Core ◽  
Electron Energy Loss ◽  
Electron Excitations ◽  
Electron Energy Loss Spectra

Core edges in electron energy loss spectra are generally complicated by thickness effects involving plural inelastic scattering. The fine structure can be modified and errors can be caused in quantitation based on measured edge intensities. Sometimes plural scattering can confuse even identification of elements. In this paper we describe a practical method for eliminating these difficulties.We derive the single scattering distribution, assuming valence electron excitation is small in the core loss region, a reasonable approximation for edges above 100 or 200 eV and for thicknesses of a few hundred Å. We can then separate the spectrum into a “high loss” region H(E) consisting of core edges (less background) and a “low loss” region L(E) containing the zero loss peak, plasmons and one-electron excitations.

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