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Author Wang, A.; Turner, S.; Van Aert, S.; van Dyck, D.
Title An alternative approach to determine attainable resolution directly from HREM images Type A1 Journal article
Year 2013 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 133 Issue Pages 50-61
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract The concept of resolution in high-resolution electron microscopy (HREM) is the power to resolve neighboring atoms. Since the resolution is related to the width of the point spread function of the microscope, it could in principle be determined from the image of a point object. However, in electron microscopy there are no ideal point objects. The smallest object is an individual atom. If the width of an atom is much smaller than the resolution of the microscope, this atom can still be considered as a point object. As the resolution of the microscope enters the sub-Å regime, information about the microscope is strongly entangled with the information about the atoms in HREM images. Therefore, we need to find an alternative method to determine the resolution in an object-independent way. In this work we propose to use the image wave of a crystalline object in zone axis orientation. Under this condition, the atoms of a column act as small lenses so that the electron beam channels through the atom column periodically. Because of this focusing, the image wave of the column can be much more peaked than the constituting atoms and can thus be a much more sensitive probe to measure the resolution. Our approach is to use the peakiness of the image wave of the atom column to determine the resolution. We will show that the resolution can be directly linked to the total curvature of the atom column wave. Moreover, we can then directly obtain the resolution of the microscope given that the contribution from the object is known, which is related to the bounding energy of the atom. The method is applied on an experimental CaTiO3 image wave.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000324471800007 Publication Date 2013-05-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record
Impact Factor 2.843 Times cited Open Access
Notes FWO; Hercules; Esteem2; esteem2_jra2 Approved Most recent IF: 2.843; 2013 IF: 2.745
Call Number UA @ lucian @ c:irua:109919 Serial 90
Permanent link to this record
 
 
Author Xu, Q.; Zandbergen, H.W.; van Dyck, D.
Title Applying an information transmission approach to extract valence electron information from reconstructed exit waves Type A1 Journal article
Year 2011 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 111 Issue 7 Pages 912-919
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract The knowledge of the valence electron distribution is essential for understanding the properties of materials. However this information is difficult to obtain from HREM images because it is easily obscured by the large scattering contribution of core electrons and by the strong dynamical scattering process. In order to develop a sensitive method to extract the information of valence electrons, we have used an information transmission approach to describe the electron interaction with the object. The scattered electron wave is decomposed in a set of basic functions, which are the eigen functions of the Hamiltonian of the projected electrostatic object potential. Each basic function behaves as a communication channel that transfers the information of the object with its own transmission characteristic. By properly combining the components of the different channels, it is possible to design a scheme to extract the information of valence electron distribution from a series of exit waves. The method is described theoretically and demonstrated by means of computer simulations.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000300461000024 Publication Date 2011-02-02
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 1 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2011 IF: 2.471
Call Number UA @ lucian @ c:irua:93623 Serial 146
Permanent link to this record
 
 
Author Chen, J.H.; van Dyck, D.; op de Beeck, M.; van Landuyt, J.
Title Computational comparisons between the conventional multislice method and the third-order multislice method for calculating high-energy electron diffraction and imaging Type A1 Journal article
Year 1997 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 69 Issue Pages 219-240
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1997YG59500001 Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 11 Open Access
Notes Approved Most recent IF: 2.843; 1997 IF: 1.600
Call Number UA @ lucian @ c:irua:21416 Serial 455
Permanent link to this record
 
 
Author van den Broek, W.; Rosenauer, A.; Goris, B.; Martinez, G.T.; Bals, S.; Van Aert, S.; van Dyck, D.
Title Correction of non-linear thickness effects in HAADF STEM electron tomography Type A1 Journal article
Year 2012 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 116 Issue Pages 8-12
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract In materials science, high angle annular dark field scanning transmission electron microscopy is often used for tomography at the nanometer scale. In this work, it is shown that a thickness dependent, non-linear damping of the recorded intensities occurs. This results in an underestimated intensity in the interior of reconstructions of homogeneous particles, which is known as the cupping artifact. In this paper, this non-linear effect is demonstrated in experimental images taken under common conditions and is reproduced with a numerical simulation. Furthermore, an analytical derivation shows that these non-linearities can be inverted if the imaging is done quantitatively, thus preventing cupping in the reconstruction.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000304473700002 Publication Date 2012-03-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 67 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2012 IF: 2.470
Call Number UA @ lucian @ c:irua:96558 Serial 518
Permanent link to this record
 
 
Author Wang, A.; Chen, F.R.; Van Aert, S.; van Dyck, D.
Title Direct structure inversion from exit waves: part 1: theory and simulations Type A1 Journal article
Year 2010 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 110 Issue 5 Pages 527-534
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract In order to interpret the amplitude and phase of the exit wave in terms of mass and position of the atoms, one has to invert the dynamic scattering of the electrons in the object so as to obtain a starting structure which can then be used as a seed for further quantitative structure refinement. This is especially challenging in case of a zone axis condition when the interaction of the electrons with the atom column is very strong. Based on the channelling theory we will show that the channelling map not only yields a circle on the Argand plot but also a circular defocus curve for every column. The former gives the number of atoms in each column, while the latter provides the defocus value for each column, which reveals the surface roughness at the exit plane with single atom sensitivity.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000279065700019 Publication Date 2009-12-12
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 25 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2010 IF: 2.063
Call Number UA @ lucian @ c:irua:83691 Serial 723
Permanent link to this record
 
 
Author Wang, A.; Chen, F.R.; Van Aert, S.; van Dyck, D.
Title Direct structure inversion from exit waves : part 2 : a practical example Type A1 Journal article
Year 2012 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 116 Issue Pages 77-85
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract This paper is the second part of a two-part paper on direct structure inversion from exit waves. In the first part, a method has been proposed to quantitatively determine structure parameters with atomic resolution such as atom column positions, surface profile and the number of atoms in the atom columns. In this part, the theory will be demonstrated by means of a Au[110] exit wave reconstructed from a set of focal-series images. The procedures to analyze the experimentally reconstructed exit wave in terms of quantitative structure information are described in detail.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000304473700011 Publication Date 2012-03-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 8 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2012 IF: 2.470
Call Number UA @ lucian @ c:irua:96660 Serial 724
Permanent link to this record
 
 
Author den Dekker, A.J.; Van Aert, S.; van Dyck, D.; van den Bos, A.; Geuens, P.
Title Does a monochromator improve the precision in quantitative HRTEM? Type A1 Journal article
Year 2001 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 89 Issue Pages 275-290
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000172667000004 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 22 Open Access
Notes Approved Most recent IF: 2.843; 2001 IF: 1.890
Call Number UA @ lucian @ c:irua:47518 Serial 746
Permanent link to this record
 
 
Author De Meulenaere, P.; van Dyck, D.; Van Tendeloo, G.; van Landuyt, J.
Title Dynamical electron diffraction in substitutionally disordered column structures Type A1 Journal article
Year 1995 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 60 Issue 1 Pages 171-185
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract For column structures, such as fee-based alloys viewed along the cube direction, the concept of electron channelling through the atom columns is more and more used to interpret the corresponding HREM images. In the case of(partially) disordered columns, the projected potential approach which is used in the channelling description must be questioned since the arrangement of the atoms along the beam direction might affect the exit wave of the electrons. In this paper, we critically inspect this top-bottom effect using multi-slice calculations. A modified channelling theory is introduced which turns out to be very appropriate for the interpretation of these results. For substitutionally disordered column structures, it is also discussed how to link the chemical composition of the material to statistical data of the HREM image. This results in a convenient tool to discern images taken at different thicknesses and focus values.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1995TG59500017 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.436 Times cited 14 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:13013 Serial 770
Permanent link to this record
 
 
Author Croitoru, M.D.; van Dyck, D.; Van Aert, S.; Bals, S.; Verbeeck, J.
Title An efficient way of including thermal diffuse scattering in simulation of scanning transmission electron microscopic images Type A1 Journal article
Year 2006 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 106 Issue 10 Pages 933-940
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT); Vision lab
Abstract We propose an improved image simulation procedure for atomic-resolution annular dark-field scanning transmission electron microscopy (STEM) based on the multislice formulation, which takes thermal diffuse scattering fully into account. The improvement with regard to the classical frozen phonon approach is realized by separating the lattice configuration statistics from the dynamical scattering so as to avoid repetitive calculations. As an example, the influence of phonon scattering on the image contrast is calculated and investigated. STEM image simulation of crystals can be applied with reasonable computing times to problems involving a large number of atoms and thick or large supercells.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000240397200006 Publication Date 2006-05-10
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 18 Open Access
Notes Fwo; Fwo-V Approved Most recent IF: 2.843; 2006 IF: 1.706
Call Number UA @ lucian @ c:irua:87604UA @ admin @ c:irua:87604 Serial 876
Permanent link to this record
 
 
Author Van Aert, S.; Geuens, P.; van Dyck, D.; Kisielowski, C.; Jinschek, J.R.
Title Electron channelling based crystallography Type A1 Journal article
Year 2007 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 107 Issue 6/7 Pages 551-558
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000245341300015 Publication Date 2006-12-13
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 32 Open Access
Notes Approved Most recent IF: 2.843; 2007 IF: 1.996
Call Number UA @ lucian @ c:irua:64286 Serial 913
Permanent link to this record
 
 
Author Luyten, W.; Krekels, T.; Amelinckx, S.; Van Tendeloo, G.; van Dyck, D.; van Landuyt, J.
Title Electron diffraction effects of conical, helically wound, graphite whiskers Type A1 Journal article
Year 1993 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 49 Issue Pages 123-131
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1993KV56700014 Publication Date 2002-10-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.436 Times cited 14 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:6784 Serial 917
Permanent link to this record
 
 
Author Potapov, P.; Lichte, H.; Verbeeck, J.; van Dyck, D.
Title Experiments on inelastic electron holography Type A1 Journal article
Year 2006 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 106 Issue 11-12 Pages 1012-1018
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Using the combination of an electron biprism and an energy filter, the coherence distribution in an inelastically scattered wave-field is measured. It is found that the degree of coherence decreases rapidly with increasing distance between two superimposed points in the object, and with increasing energy-loss. In a Si sample, coherence of plasmon scattering increases in vacuum with the distance from the edge of the sample. (c) 2006 Published by Elsevier B.V.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000241592900009 Publication Date 2006-07-07
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 28 Open Access
Notes Approved Most recent IF: 2.843; 2006 IF: 1.706
Call Number UA @ lucian @ c:irua:61380UA @ admin @ c:irua:61380 Serial 1147
Permanent link to this record
 
 
Author de Backer, A.; Van Aert, S.; van Dyck, D.
Title High precision measurements of atom column positions using model-based exit wave reconstruction Type A1 Journal article
Year 2011 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 111 Issue 9/10 Pages 1475-1482
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract In this paper, it has been investigated how to measure atom column positions as accurately and precisely as possible using a focal series of images. In theory, it is expected that the precision would considerably improve using a maximum likelihood estimator based on the full series of focal images. As such, the theoretical lower bound on the variances of the unknown atom column positions can be attained. However, this approach is numerically demanding. Therefore, maximum likelihood estimation has been compared with the results obtained by fitting a model to a reconstructed exit wave rather than to the full series of focal images. Hence, a real space model-based exit wave reconstruction technique based on the channelling theory is introduced. Simulations show that the reconstructed complex exit wave contains the same amount of information concerning the atom column positions as the full series of focal images. Only for thin samples, which act as weak phase objects, this information can be retrieved from the phase of the reconstructed complex exit wave.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000300461200004 Publication Date 2011-07-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 8 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2011 IF: 2.471
Call Number UA @ lucian @ c:irua:91879 Serial 1438
Permanent link to this record
 
 
Author Lobato, I.; van Dyck, D.
Title Improved multislice calculations for including higher-order Laue zones effects Type A1 Journal article
Year 2012 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 119 Issue Pages 63-71
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract A new method for including higher-order Laue zones (HOLZs) effects in an efficient way in electron scattering simulations has been developed and tested by detail calculations. The calculated results by the conventional multislice (CMS) method and the improved conventional multislice (ICMS) method using a large dynamical aperture to avoid numerical errors are compared with accurate results. We have found that the zero-order Laue zones (ZOLZs) reflection cannot be properly described only using the projected potential in the whole unit cell; in general, we need to subslice the electrostatic potential inside the unit cell. It is shown that the ICMS method has higher accuracy than the CMS method for the calculation of the ZOLZ, HOLZ and Pseudo-HOLZ reflections. Hence, ICMS method allows to use a larger slice thickness than the CMS method and reduces the calculation time. (C) 2012 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000308079200011 Publication Date 2012-01-14
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 6 Open Access
Notes Approved Most recent IF: 2.843; 2012 IF: 2.470
Call Number UA @ lucian @ c:irua:101902 Serial 1567
Permanent link to this record
 
 
Author Potapov, P.L.; Verbeeck, J.; Schattschneider, P.; Lichte, H.; van Dyck, D.
Title Inelastic electron holography as a variant of the Feynman thought experiment Type A1 Journal article
Year 2007 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 107 Issue 8 Pages 559-567
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Using a combination of electron holography and energy filtering, interference fringes produced after inelastic interaction of electrons with hydrogen molecules are examined. Surprisingly, the coherence of inelastic scattering increases when moving from the surface of a hydrogen-containing bubble to the vacuum. This phenomenon can be understood in terms of the Feynman two-slit thought experiment with a variable ambiguity of the which-way registration. (C) 2006 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000246937000001 Publication Date 2006-12-16
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 13 Open Access
Notes Fwo G.0147.06 Approved Most recent IF: 2.843; 2007 IF: 1.996
Call Number UA @ lucian @ c:irua:103588UA @ admin @ c:irua:103588 Serial 1605
Permanent link to this record
 
 
Author Fanidis, C.; van Dyck, D.; van Landuyt, J.
Title Inelastic scattering of high-energy electrons in a crystal in thermal equilibrium with the environment: 1: theoretical framework Type A1 Journal article
Year 1992 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 41 Issue Pages 55-64
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1992HX68100005 Publication Date 2002-10-18
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.436 Times cited 17 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:4092 Serial 1608
Permanent link to this record
 
 
Author Fanidis, C.; van Dyck, D.; van Landuyt, J.
Title Inelastic scattering of high-energy electrons in a crystal in thermal equilibrium with the environment: part 2: solution of the equations and applications to concrete cases Type A1 Journal article
Year 1993 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 48 Issue Pages 133-164
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1993KM78800013 Publication Date 0000-00-00
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991 ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.436 Times cited 6 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:6782 Serial 1609
Permanent link to this record
 
 
Author van Dyck, D.; Van Aert, S.; den Dekker, A.J.; van den Bos, A.
Title Is atomic resolution transmission electron microscopy able to resolve and refine amorphous structures? Type A1 Journal article
Year 2003 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 98 Issue Pages 27-42
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000186831500003 Publication Date 2003-04-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 26 Open Access
Notes Approved Most recent IF: 2.843; 2003 IF: 1.665
Call Number UA @ lucian @ c:irua:47516 Serial 1749
Permanent link to this record
 
 
Author Van Aert, S.; Chen, J.H.; van Dyck, D.
Title Linear versus non-linear structural information limit in high-resolution transmission electron microscopy Type A1 Journal article
Year 2010 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 110 Issue 11 Pages 1404-1410
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract A widely used performance criterion in high-resolution transmission electron microscopy (HRTEM) is the information limit. It corresponds to the inverse of the maximum spatial object frequency that is linearly transmitted with sufficient intensity from the exit plane of the object to the image plane and is limited due to partial temporal coherence. In practice, the information limit is often measured from a diffractogram or from Young's fringes assuming a weak phase object scattering beyond the inverse of the information limit. However, for an aberration corrected electron microscope, with an information limit in the sub-angstrom range, weak phase objects are no longer applicable since they do not scatter sufficiently in this range. Therefore, one relies on more strongly scattering objects such as crystals of heavy atoms observed along a low index zone axis. In that case, dynamical scattering becomes important such that the non-linear and linear interaction may be equally important. The non-linear interaction may then set the experimental cut-off frequency observed in a diffractogram. The goal of this paper is to quantify both the linear and the non-linear information transfer in terms of closed form analytical expressions. Whereas the cut-off frequency set by the linear transfer can be directly related with the attainable resolution, information from the non-linear transfer can only be extracted using quantitative, model-based methods. In contrast to the historic definition of the information limit depending on microscope parameters only, the expressions derived in this paper explicitly incorporate their dependence on the structure parameters as well. In order to emphasize this dependence and to distinguish from the usual information limit, the expressions derived for the inverse cut-off frequencies will be referred to as the linear and non-linear structural information limit. The present findings confirm the well-known result that partial temporal coherence has different effects on the transfer of the linear and non-linear terms, such that the non-linear imaging contributions are damped less than the linear imaging contributions at high spatial frequencies. This will be important when coherent aberrations such as spherical aberration and defocus are reduced.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000282562100008 Publication Date 2010-07-15
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 6 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2010 IF: 2.063
Call Number UA @ lucian @ c:irua:83689 Serial 1821
Permanent link to this record
 
 
Author den Dekker, A.J.; Van Aert, S.; van den Bos, A.; van Dyck, D.
Title Maximum likelihood estimation of structure parameters from high resolution electron microscopy images: part 1: a theoretical framework Type A1 Journal article
Year 2005 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 104 Issue 2 Pages 83-106
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000230526400001 Publication Date 2005-04-09
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 70 Open Access
Notes Approved Most recent IF: 2.843; 2005 IF: 2.490
Call Number UA @ lucian @ c:irua:57229 Serial 1959
Permanent link to this record
 
 
Author Van Aert, S.; den Dekker, A.J.; van den Bos, A.; van Dyck, D.; Chen, J.H.
Title Maximum likelihood estimation of structure parameters from high resolution electron microscopy images : part 2 : a practical example Type A1 Journal article
Year 2005 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 104 Issue 2 Pages 107-125
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000230526400002 Publication Date 2005-04-08
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 37 Open Access
Notes Approved Most recent IF: 2.843; 2005 IF: 2.490
Call Number UA @ lucian @ c:irua:57131 Serial 1960
Permanent link to this record
 
 
Author Croitoru, M.D.; van Dyck, D.; Liu, Y.Z.; Zhang, Z.
Title Measurement of specimen thickness by phase change determination in TEM Type A1 Journal article
Year 2008 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 108 Issue 12 Pages 1616-1622
Keywords A1 Journal article; Condensed Matter Theory (CMT); Electron microscopy for materials research (EMAT); Vision lab
Abstract A non-destructive method for measuring the thickness of thin amorphous films composed of light elements has been developed. The method employs the statistics of the phase of the electron exit wave function. The accuracy of this method has been checked numerically by the multislice method and compared with that based on the mean inner potential.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000260808300016 Publication Date 2008-06-23
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 2 Open Access
Notes Approved Most recent IF: 2.843; 2008 IF: 2.629
Call Number UA @ lucian @ c:irua:75643 Serial 1961
Permanent link to this record
 
 
Author Van den Broek, W.; Rosenauer, A.; Van Aert, S.; Sijbers, J.; van Dyck, D.
Title A memory efficient method for fully three-dimensional object reconstruction with HAADF STEM Type A1 Journal article
Year 2014 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 141 Issue Pages 22-31
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract The conventional approach to object reconstruction through electron tomography is to reduce the three-dimensional problem to a series of independent two-dimensional slice-by-slice reconstructions. However, at atomic resolution the image of a single atom extends over many such slices and incorporating this image as prior knowledge in tomography or depth sectioning therefore requires a fully three-dimensional treatment. Unfortunately, the size of the three-dimensional projection operator scales highly unfavorably with object size and readily exceeds the available computer memory. In this paper, it is shown that for incoherent image formation the memory requirement can be reduced to the fundamental lower limit of the object size, both for tomography and depth sectioning. Furthermore, it is shown through multislice calculations that high angle annular dark field scanning transmission electron microscopy can be sufficiently incoherent for the reconstruction of single element nanocrystals, but that dynamical diffraction effects can cause classification problems if more than one element is present. (C) 2014 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000335766600004 Publication Date 2014-03-22
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 6 Open Access
Notes ResearchFoundationFlanders(FWO;G.0393.11; G.0064.10;andG.0374.13); European Union Seventh Frame- workProgramme [FP7/2007-2013]under Grant agreement no. 312483 (ESTEEM2).; esteem2jra2; esteem2jra4 Approved Most recent IF: 2.843; 2014 IF: 2.436
Call Number UA @ lucian @ c:irua:117650 Serial 1992
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Author Wang, A.; Chen, F.R.; Van Aert, S.; van Dyck, D.
Title A method to determine the local surface profile from reconstructed exit waves Type A1 Journal article
Year 2011 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 111 Issue 8 Pages 1352-1359
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Reconstructed exit waves are useful to quantify unknown structure parameters such as the position and composition of the atom columns at atomic scale. Existing techniques provide a complex wave in a flat plane which is close to the plane where the electrons leave the atom columns. However, due to local deviation in the flatness of the exit surface, there will be an offset between the plane of reconstruction and the actual exit of a specific atom column. Using the channelling theory, it has been shown that this defocus offset can in principle be determined atom column-by-atom column. As such, the surface roughness could be quantified at atomic scale. However, the outcome strongly depends on the initial plane of reconstruction especially in a crystalline structure. If this plane is further away from the true exit, the waves of the atom columns become delocalized and interfere mutually which strongly complicates the interpretation of the exit wave in terms of the local structure. In this paper, we will study the delocalization with defocus using the channelling theory in a more systematic way.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000300461100049 Publication Date 2011-05-03
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 3 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2011 IF: 2.471
Call Number UA @ lucian @ c:irua:88941 Serial 2017
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Author van den Broek, W.; Van Aert, S.; van Dyck, D.
Title A model based atomic resolution tomographic algorithm Type A1 Journal article
Year 2009 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 109 Issue 12 Pages 1485-1490
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Tomography with high angular annular dark field scanning transmission electron microscopy at atomic resolution can be greatly improved if one is able to take advantage of prior knowledge. In this paper we present a reconstruction technique that explicitly takes into account the microscope parameters and the atomic nature of the projected object. This results in a more accurate estimate of the atomic positions and in a good resistance to noise. The reconstruction is a maximum likelihood estimator of the object. Moreover, the limits to the precision have been explored, allowing for a prediction of the amount of expected noise in the reconstruction for a certain experimental setup. We believe that the proposed reconstruction technique can be generalized to other tomographic experiments.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000271840200010 Publication Date 2009-08-28
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 17 Open Access
Notes Approved Most recent IF: 2.843; 2009 IF: 2.067
Call Number UA @ lucian @ c:irua:78588 Serial 2097
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Author van den Broek, W.; Van Aert, S.; van Dyck, D.
Title A model based reconstruction technique for depth sectioning with scanning transmission electron microscopy Type A1 Journal article
Year 2010 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 110 Issue 5 Pages 548-554
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract Depth sectioning in high angular annular dark field scanning transmission electron microscopy is considered a candidate for three-dimensional characterization on the atomic scale. However at present the depth resolution is still far from the atomic level, due to strong limitations in the opening angle of the beam. In this paper we introduce a new, parameter based tomographic reconstruction algorithm that allows to make maximal use of the prior knowledge about the constituent atom types and the microscope settings, so as to retrieve the atomic positions and push the resolution to the atomic level in all three dimensions.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000279065700022 Publication Date 2009-09-21
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 16 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2010 IF: 2.063
Call Number UA @ lucian @ c:irua:83690 Serial 2104
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Author De Meulenaere, P.; Van Tendeloo, G.; van Landuyt, J.; van Dyck, D.
Title On the interpretation of HREM images of partially ordered alloys Type A1 Journal article
Year 1995 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 60 Issue 2 Pages 265-282
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract The ordering for 11/20 alloys has been studied by high-resolution electron microscopy (HREM). The distribution of the intensity maxima in the HREM image have been statistically examined, which provides a profound basis for the image interpretation. Processing of the HREM images allows ''dark-field'' images to be obtained, exhibiting a two-dimensional distribution of those columns which contain the most information in order to interpret the short-range order correlations. Pair correlations and higher cluster correlations between projected columns can be visualised, providing unique information about the ordering as retrieved from an experimental result without any other assumption. The method has been applied to Au4Cr and to Au4Mn to interpret the quenched short-range order state and the transition to long-range order.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos A1995TZ14700008 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.436 Times cited 20 Open Access
Notes Approved no
Call Number UA @ lucian @ c:irua:13014 Serial 2438
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Author Van Aert, S.; den Dekker, A.J.; van Dyck, D.; van den Bos, A.
Title Optimal experimental design of STEM measurement of atom column positions Type A1 Journal article
Year 2002 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 90 Issue Pages 273-289
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000174770900004 Publication Date 2002-07-25
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 35 Open Access
Notes Approved Most recent IF: 2.843; 2002 IF: 1.772
Call Number UA @ lucian @ c:irua:47517 Serial 2483
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Author Verbeeck, J.; van Dyck, D.; Lichte, H.; Potapov, P.; Schattschneider, P.
Title Plasmon holographic experiments: theoretical framework Type A1 Journal article
Year 2005 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 102 Issue 3 Pages 239-255
Keywords A1 Journal article; Electron microscopy for materials research (EMAT); Vision lab
Abstract A theoretical framework is described to understand the results of plasmon holography experiments leading to insight in the meaning of the experimental results and pointing out directions for future experiments. The framework is based on the formalism of mutual intensity to describe how coherence is transferred through an optical system. For the inelastic interaction with the object, an expression for the volume. plasmon excitations in a free electron gas is used as a model for the behaviour of aluminium. The formalism leads to a clear graphical intuitive tool for under-standing the experiments. It becomes evident that the measured coherence is solely related to the angular distribution of the plasmon scattering in the case of bulk plasmons. After describing the framework, the special case of coherence outside a spherical particle is treated and the seemingly controversial idea of a plasmon with a limited coherence length obtained front experiments is clarified. (C) 2004 Elsevier B.V. All rights reserved.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000226436600010 Publication Date 2004-11-05
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 43 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2005 IF: 2.490
Call Number UA @ lucian @ c:irua:57133UA @ admin @ c:irua:57133 Serial 2643
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Author Wang, A.; Van Aert, S.; Goos, P.; van Dyck, D.
Title Precision of three-dimensional atomic scale measurements from HRTEM images : what are the limits? Type A1 Journal article
Year 2012 Publication (down) Ultramicroscopy Abbreviated Journal Ultramicroscopy
Volume 114 Issue Pages 20-30
Keywords A1 Journal article; Engineering Management (ENM); Electron microscopy for materials research (EMAT); Vision lab
Abstract In this paper, we investigate to what extent high resolution transmission electron microscopy images can be used to measure the mass, in terms of thickness, and surface profile, corresponding to the defocus offset, of an object at the atomic scale. Therefore, we derive an expression for the statistical precision with which these object parameters can be estimated in a quantitative analysis. Evaluating this expression as a function of the microscope settings allows us to derive the optimal microscope design. Acquiring three-dimensional structure information in terms of thickness turns out to be much more difficult than obtaining two-dimensional information on the projected atom column positions. The attainable precision is found to be more strongly affected by processes influencing the image contrast, such as phonon scattering, than by the specific choice of microscope settings. For a realistic incident electron dose, it is expected that atom columns can be distinguished with single atom sensitivity up to a thickness of the order of the extinction distance. A comparable thickness limit is determined to measure surface steps of one atom. An increase of the electron dose shifts the limiting thickness upward due to an increase in the signal-to-noise ratio.
Address
Corporate Author Thesis
Publisher Place of Publication Amsterdam Editor
Language Wos 000301954300003 Publication Date 2012-01-06
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0304-3991; ISBN Additional Links UA library record; WoS full record; WoS citing articles
Impact Factor 2.843 Times cited 5 Open Access
Notes Fwo Approved Most recent IF: 2.843; 2012 IF: 2.470
Call Number UA @ lucian @ c:irua:94116 Serial 2692
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