Evaluation of theoretical models for elastic electron backscattering from surfaces

Dubus, Alain; Jabłoński, A.; Tougaard, S.

doi:10.1016/s0079-6816(99)00018-0

Cited by 66 publications

(42 citation statements)

References 69 publications

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“…Since the problem is isotropic, as it was pointed out also in [1], the equations becomes two-dimensional, the variables are z and the angle w between the zaxis and the direction of the electron. In order to estimate the distribution of the backscattered electrons, we compute the integrals:…”

Section: Overview Of the Problemmentioning

confidence: 97%

“…In [1], using the fact that the problem is monoenergetic, the target is homogeneous, etc., it is shown that the flow of electrons Φ(z, Ω) satisfies the following simplified form of the Boltzmann equation:…”

Section: Overview Of the Problemmentioning

confidence: 99%

“…Therefore the electron transport problem is a monoenergetic one. In [1] the problem is formulated in terms of a Boltzmann equation and then many different numerical methods are compared. The Monte Carlo approach is considered as one of the most accurate ones from theoretical viewpoint.…”

Section: Introductionmentioning

confidence: 99%

“…However, in order to decrease the statistical error, long computational times are needed. Having the FORTRAN sources of the programs, used for the Monte Carlo computations in [1], we were able to substantially reduce the computational times, needed to obtain results with the same statistical error.…”

Section: Introductionmentioning

confidence: 99%

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An Improved Monte Carlo Algorithm for Elastic Electron Backscattering from Surfaces

Dimov

Atanassov

Durchova

2001

Large-Scale Scientific Computing

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Abstract. The problen of the backscattering of electrons from metal targets is subject of extensive theoreticel and experimental work in surface analysis. We are interested in the angular distribution of the backscattered electrons. The flow of electrons satisfies an integral equation, which might be solved by Monte Carlo methods. The Monte Carlo approach, used by A. Dubus, A. Jablonski and S. Tougaard in their paper "Evaluation of theoretical models for elastic electron backscattering from surfaces" (1999), is based upon direct simulation of the physical process. We introduce different weights in the Monte Carlo algorithm, which decrease the variance. We also introduce artificial absorption probability and demonstrate significant improvements in the efficiency of the algorithm. Results of extensive numerical tests are presented.

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Section: Overview Of the Problemmentioning

confidence: 97%

Section: Overview Of the Problemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An Improved Monte Carlo Algorithm for Elastic Electron Backscattering from Surfaces

Dimov

Atanassov

Durchova

2001

Large-Scale Scientific Computing

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“…13,14 It has been found that the most realistic model is implemented in the Monte Carlo simulation strategies for electron transport in the surface region. Consequently, we expect that these simulations provide the most accurate values of the elastically backscattered intensity.…”

Section: Theorymentioning

confidence: 99%

Remarks on Some Reference Materials for Applications in Elastic Peak Electron Spectroscopy

Jabłoński

Zemek

2010

ANAL. SCI.

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The quantification of results of electron spectroscopies, AES and XPS, requires knowledge of the inelastic mean free path (IMFP) of signal electrons in solids. This parameter determines the surface sensitivity of both techniques. There are two methods of determining the IMFPs that provide these parameters in agreement with the definition: (i) calculations based on the experimental optical data, and (ii) calculations based on measurements of the electron elastic backscattering intensity. The latter method requires the use of some reference material for which the IMFP is known. In 1999, an extensive analysis of the published IMFPs has been performed; the results indicated that there is a very good agreement between the calculated and measured IMFPs for four elemental solids: Ni, Cu, Ag and Au. The averaged IMFPs for these elements are known under the name of the recommended IMFPs. However, no preference among these four elements has been established. In the present work, an attempt is made to select an element for which the recommended IMFPs result in the best agreement between the calculated and measured intensities of elastic electron backscattering. For this purpose, the elastic backscattering intensity has been measured at eight electron energies varying from 200 to 1500 eV. At each energy, the intensity was measured over a wide range of emission angles from 35 to 74 . The experiments were accompanied with Monte Carlo calculations of the elastic backscattering probability for the same energies and experimental configurations. It has been found, from comparison, that the best agreement is observed for Au, and this element is thus recommended as the reference material. It has been shown that the shape of the emission angle dependence of the elastic backscattering intensity is noticeably influenced by the surface energy losses.

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Determination of the IMFP from electron elastic backscattering probability

Jabłoński

2000

Surf. Interface Anal.

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Theoretical models for elastic electron backscattering from surfaces have gained much attention in the recent years. One of the stimulating factors is the need for a reliable theoretical relation between the elastic backscattering probability and the electron inelastic mean free path (IMFP) in the surface region. Such a relation would provide a convenient tool for determining the IMFP. At present, the Monte Carlo simulations are considered to be most reliable for a description of elastic electron backscattering. This approach, however, usually needs considerable computing time. The analytical theoretical models are derived after introducing additional simplifying assumptions that may lead to a certain systematic deviation with respect to the Monte Carlo simulations. In the present work, a modification of the theoretical model proposed by Oswald, Kasper and Gaukler (OKG) is compared with Monte Carlo simulations. Calculations were made for the most frequently used experimental geometry (cylindrical mirror analyses with normal incidence of the primary beam) and a wide range of energies and atomic numbers. It has been found that the elastic backscattering probabilities calculated from the OKG model and the Monte Carlo model compare very well if we assume realistic values of the IMFP. For this reason, the OKG model is recommended for calculations associated with determination of the IMFP when the experimental geometry similar to that of the CMA is used. Copyright © 2000 John Wiley & Sons, Ltd.

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Evaluation of theoretical models for elastic electron backscattering from surfaces

Cited by 66 publications

References 69 publications

An Improved Monte Carlo Algorithm for Elastic Electron Backscattering from Surfaces

An Improved Monte Carlo Algorithm for Elastic Electron Backscattering from Surfaces

Remarks on Some Reference Materials for Applications in Elastic Peak Electron Spectroscopy

Determination of the IMFP from electron elastic backscattering probability

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