The influence of specimen thickness in quantitative electron energy loss spectroscopy: II

Intensity Ratio ◽

Mean Free Path ◽

Specimen Thickness ◽

Subsequent Work ◽

The Mean ◽

Plasmon Loss ◽

In a previous paper it was shown that the influence of specimen thickness on quantitative electron energy loss spectroscopy (EELS) can be judged by measuring the intensity ratio of any two characteristic EEL edges as a function of thickness. If the specimen is homogeneous and thickness effects are neglegible then, one can show from Egerton’s formulation that this intensity ratio should be a constant. Any departure from a constant value indicates a breakdown of the quantitative theory due to thickness related effects. It was shown that if the ratio of Ip/IO (Ip = intensity of plasmon loss, IO = intensity of zero loss) exceeds ∼ 0.3 then quantitative analysis can be in significant error. In subsequent work Egerton showed that a better measure is the ratio of ℓn(It/IO) which is related to the ratio of t/λ. Here It is the total energy loss intensity, t the specimen thickness and λ the mean-free path for total inelastic scattering.

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 ◽

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.

Some problems and solutions in electron energy loss spectroscopy of cryosections

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100148666 ◽

1993 ◽

Vol 51 ◽

pp. 566-567

Author(s):

Zhifeng Shao ◽

Ruoya Ho ◽

Andrew P. Somlyo

Keyword(s):

High Resolution ◽

Energy Loss ◽

Electron Energy ◽

Biological Research ◽

Specimen Thickness ◽

Elemental Distribution ◽

Electron Dose ◽

Simple Assumption ◽

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.

The Influence of Specimen Thickness in Quantitative Electron Energy Loss Spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600000441 ◽

1980 ◽

Vol 38 ◽

pp. 112-113

Author(s):

Nestor J. Zaluzec

Keyword(s):

Quantitative Analysis ◽

Adverse Effects ◽

Energy Loss ◽

Electron Energy ◽

Materials Science ◽

Light Element ◽

Specimen Thickness ◽

Element Analysis ◽

The application of electron energy loss spectroscopy (EELS) to light element analysis is rapidly becoming an important aspect of the microcharacterization of solids in materials science, however relatively stringent requirements exist on the specimen thickness under which one can obtain EELS data due to the adverse effects of multiple inelastic scattering.1,2 This study was initiated to determine the limitations on quantitative analysis of EELS data due to specimen thickness.

Determination of electron inelastic mean free path of three transition metals from reflection electron energy loss spectroscopy spectrum measurement data

The European Physical Journal D ◽

10.1140/epjd/e2018-90551-6 ◽

2019 ◽

Vol 73 (2) ◽

Cited By ~ 7

Author(s):

Lihao Yang ◽

Károly Tőkési ◽

Bo Da ◽

Zejun Ding

Keyword(s):

Energy Loss ◽

Free Path ◽

Electron Energy ◽

Measurement Data ◽

Mean Free Path ◽

Spectrum Measurement ◽

Inelastic Mean Free Path ◽

Thickness Measurement by EELS

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100118862 ◽

1985 ◽

Vol 43 ◽

pp. 398-399

Author(s):

R. F. Egerton ◽

S. C. Cheng

Keyword(s):

Energy Loss ◽

Incident Energy ◽

Mean Free Path ◽

Thickness Measurement ◽

Loss Peak ◽

Wide Range ◽

Integrated Intensity ◽

The Mean ◽

Electron energy-loss spectroscopy offers a rapid method of estimating the local thickness of a TEM specimen. The best-known procedure requires only measurement of the integrated intensity IO under the zero-loss peak and of the integral It under the whole spectrum (up to some suitable energy loss Δ). The thickness t is obtained from the formula:where λ(β) is the mean free path for inelastic scattering up to some angle β which is determined by the collection aperture (e.g. objective aperture in CTEM). In agreement with previous work we find that Eq. (1) is applicable over a wide range of thickness, typically 10-500 nm for EO = 100keV incident energy; see Fig. 1. Some deviation at large thickness might be expected as a result of the angular broadening produced by plural scattering, and because of contributions from electrons elastically scattered through angles greater than β.

Determining Inelastic Mean Free Path by Electron Energy Loss Spectroscopy

Microscopy and Microanalysis ◽

10.1017/s1431927606061770 ◽

2006 ◽

Vol 12 (S02) ◽

pp. 1186-1187 ◽

Cited By ~ 4

Author(s):

Q Jin ◽

D Li

Keyword(s):

Energy Loss ◽

Free Path ◽

Electron Energy ◽

Mean Free Path ◽

Inelastic Mean Free Path ◽

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

Electron Energy-Loss Spectroscopy in a 400kV Transmission Electron Microscope (TEELS)

MRS Proceedings ◽

10.1557/proc-62-139 ◽

1985 ◽

Vol 62 ◽

Author(s):

T. Oikawa ◽

J. Hosoi ◽

Y. Kokubo ◽

Y. Bando ◽

J. L. Lehman

Keyword(s):

Energy Loss ◽

Electron Energy ◽

Digital Processing ◽

Thickness Effect ◽

Specimen Thickness ◽

Powerful Technique ◽

Transmission Electron ◽

Atom Interaction ◽

ABSTRACTElectron energy-loss spectroscopy in the transmission electron microscopy (TEELS) is a powerful technique to investigate the “electron and atom interaction in specimen microareas”.This paper reports some experimental data of TEELS concerning specimen thickness effect and advantages of 400 kV TEM, and introduces newly developed digital processing of EELS spectra, which is a powerful technique to get the information from the specimen materials.

Electron energy loss spectroscopy of nanometer-sized Cr crystallites in MgO single crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153956 ◽

1989 ◽

Vol 47 ◽

pp. 396-397

Author(s):

N. Tanaka ◽

K. Mihama ◽

R. J. Graham ◽

J. K. Weiss ◽

J. M. Cowley

Keyword(s):

Energy Loss ◽

Electron Energy ◽

Carbon Film ◽

Composite Films ◽

Atomic Clusters ◽

Preparation Methods ◽

The Mean ◽

Points Of View ◽

Conposite films including nanometer-sized metal crystallites and atomic clusters in ceramics or insulators are currently of great interest from the points of view of basic science and technology. We have developed new single crystalline composite films of magnesium oxide(MgO) and nanometer-sized metal crystallites. The crystalline structures were studied in detail by HREM and nanometer-area diffraction. In the present study, electron energy loss spectroscopy(EELS) of Chromium(Cr)-MgO composite films was performed to study the oxidation state of the Cr crystallites in the MgO matrix.Preparation methods of the composite films were described in detail in a previous paper. Cr and MgO were simultaneously deposited on a (001) cleaved surface of sodium chloride in UHV conditions of 10−6 Pa, the mean thickness of Cr and MgO being 3 nm and 30 nm, respectively. The composite films were separated from the substrate in water and mounted on a perforated carbon film. The EELS was carried out at 100 kV by using an electron microscope with a field emission gun (Philips FEG 400ST) equipped with a parallel detection spectrometer (Gatan 666).