Retrieval of the single loss spectrum with Johnson-Spence method

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144978 ◽

1986 ◽

Vol 44 ◽

pp. 720-721

Author(s):

Xudong Weng

Keyword(s):

Energy Loss ◽

Cross Sections ◽

Additional Assumption ◽

Relaxation Times ◽

Single Scattering ◽

Energy Gain ◽

Low Loss ◽

Multiple Data ◽

Pass Through ◽

Electron Energy Loss

A method using fourier transform and logarithm for the retrieval of the single scattering electron energy loss spectrum from the experimental multiple data has been described and used previously. However, the uniqueness of this method is proved only under an additional assumption that no energy gain processes occur as the incident electron pass through the specimen. This proof is adopted in the later review papers. In this paper we prove the uniqueness without such an assumption, although in comparison with the energy loss processes, the energy gain processes usually have negligible differential cross sections, provided the relaxation times for the excitation inside the specimen are short enough with respect to the amount of energy loss. Also we shall compare deconvolution methods for the low loss region.

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Background Fitting in the Low-Loss Region of Electron Energy Loss Spectra

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133874 ◽

1990 ◽

Vol 48 (2) ◽

pp. 56-57

Author(s):

C P Scott ◽

A J Craven ◽

C J Gilmore ◽

A W Bowen

Keyword(s):

Energy Loss ◽

Multiple Scattering ◽

Simple Form ◽

Single Scattering ◽

Low Loss ◽

Characteristic Energy ◽

Normal Method ◽

Fitting In ◽

Electron Energy Loss ◽

Electron Energy Loss Spectra

The normal method of background subtraction in quantitative EELS analysis involves fitting an expression of the form I=AE-r to an energy window preceding the edge of interest; E is energy loss, A and r are fitting parameters. The calculated fit is then extrapolated under the edge, allowing the required signal to be extracted. In the case where the characteristic energy loss is small (E < 100eV), the background does not approximate to this simple form. One cause of this is multiple scattering. Even if the effects of multiple scattering are removed by deconvolution, it is not clear that the background from the recovered single scattering distribution follows this simple form, and, in any case, deconvolution can introduce artefacts.The above difficulties are particularly severe in the case of Al-Li alloys, where the Li K edge at ~52eV overlaps the Al L2,3 edge at ~72eV, and sharp plasmon peaks occur at intervals of ~15eV in the low loss region. An alternative background fitting technique, based on the work of Zanchi et al, has been tested on spectra taken from pure Al films, with a view to extending the analysis to Al-Li alloys.

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Highly Automated Electron Energy-Loss Spectroscopy Elemental Quantification

Microscopy and Microanalysis ◽

10.1017/s1431927614000567 ◽

2014 ◽

Vol 20 (3) ◽

pp. 798-806 ◽

Cited By ~ 1

Author(s):

Raman D. Narayan ◽

J. K. Weiss ◽

Peter Rez

Keyword(s):

User Interface ◽

Energy Loss ◽

Electron Energy ◽

Electron Energy Loss Spectroscopy ◽

Single Scattering ◽

Ease Of Use ◽

Low Loss ◽

Wide Range ◽

Fitting Algorithm ◽

Electron Energy Loss

AbstractA model-based fitting algorithm for electron energy-loss spectroscopy spectra is introduced, along with an intuitive user-interface. As with Verbeeck & Van Aert, the measured spectrum, rather than the single scattering distribution, is fit over a wide range. An approximation is developed that allows for accurate modeling while maintaining linearity in the parameters that represent elemental composition. Also, a method is given for generating a model for the low-loss background that incorporates plural scattering. Operation of the user-interface is described to demonstrate the ease of use that allows even nonexpert users to quickly obtain elemental analysis results.

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Comparison of Calculated and Recorded Electron Energy-Loss Spectra of Aluminium and Carbon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133916 ◽

1990 ◽

Vol 48 (2) ◽

pp. 64-65

Author(s):

L. Reimer ◽

R. Oelgeklaus

Keyword(s):

Fourier Transform ◽

Energy Loss ◽

Electron Energy ◽

Rotational Symmetry ◽

Mean Free Path ◽

Single Scattering ◽

Specimen Thickness ◽

Two Dimensional ◽

Image Position ◽

Electron Energy Loss

Quantitative electron energy-loss spectroscopy (EELS) needs a correction for the limited collection aperture α and a deconvolution of recorded spectra for eliminating the influence of multiple inelastic scattering. Reversely, it is of interest to calculate the influence of multiple scattering on EELS. The distribution f(w,θ,z) of scattered electrons as a function of energy loss w, scattering angle θ and reduced specimen thickness z=t/Λ (Λ=total mean-free-path) can either be recorded by angular-resolved EELS or calculated by a convolution of a normalized single-scattering function ϕ(w,θ). For rotational symmetry in angle (amorphous or polycrystalline specimens) this can be realised by the following sequence of operations :(1)where the two-dimensional distribution in angle is reduced to a one-dimensional function by a projection P, T is a two-dimensional Fourier transform in angle θ and energy loss w and the exponent -1 indicates a deprojection and inverse Fourier transform, respectively.

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Information and Dose in the Scanning Transmission Ion Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600001021 ◽

1980 ◽

Vol 38 ◽

pp. 232-233

Author(s):

Fox T. R. ◽

R. Levi-Setti

Keyword(s):

Information Retrieval ◽

Electron Microscope ◽

Elastic Scattering ◽

Energy Loss ◽

Cross Sections ◽

Previous Analysis ◽

Single Scattering ◽

Screening Length ◽

Relative Damage ◽

Scanning Transmission

At an earlier meeting [1], we discussed information retrieval in the scanning transmission ion microscope (STIM) compared with the electron microscope at the same energy. We treated elastic scattering contrast, using total elastic cross sections; relative damage was estimated from energy loss data. This treatment is valid for “thin” specimens, where the incident particles suffer only single scattering. Since proton cross sections exceed electron cross sections, a given specimen (e.g., 1 μg/cm2 of carbon at 25 keV) may be thin for electrons but “thick” for protons. Therefore, we now extend our previous analysis to include multiple scattering. Our proton results are based on the calculations of Sigmund and Winterbon [2], for 25 keV protons on carbon, using a Thomas-Fermi screened potential with a screening length of 0.0226 nm. The electron results are from Crewe and Groves [3] at 30 keV.

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Absolute, cascade-free cross sections for the2S→2Ptransition inZn+using electron-energy-loss and merged-beams methods

Physical Review Letters ◽

10.1103/physrevlett.67.30 ◽

1991 ◽

Vol 67 (1) ◽

pp. 30-33 ◽

Cited By ~ 27

Author(s):

Steven J. Smith ◽

K-F. Man ◽

R. J. Mawhorter ◽

I. D. Williams ◽

A. Chutjian

Keyword(s):

Energy Loss ◽

Electron Energy ◽

Cross Sections ◽

Electron Energy Loss

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Quantitative nanoscale water mapping in frozen-hydrated skin by low-loss electron energy-loss spectroscopy

Ultramicroscopy ◽

10.1016/j.ultramic.2010.03.014 ◽

2010 ◽

Vol 110 (7) ◽

pp. 866-876 ◽

Cited By ~ 14

Author(s):

Sergey Yakovlev ◽

Manoj Misra ◽

Shanling Shi ◽

Emre Firlar ◽

Matthew Libera

Keyword(s):

Energy Loss ◽

Electron Energy ◽

Electron Energy Loss Spectroscopy ◽

Low Loss ◽

Water Mapping ◽

Electron Energy Loss

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

Microscopy and Microanalysis ◽

10.1017/s1431927699990505 ◽

1999 ◽

Vol 5 (6) ◽

pp. 437-444 ◽

Cited By ~ 4

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.

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