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Hesam Mahmoudi Nezhad, N. (author), Ghaffarian Niasar, M. (author), Hagen, C.W. (author), Kruit, P. (author)In electron optics, calculation of the electric field plays a major role in all computations and simulations. Accurate field calculation methods such as the finite element method (FEM), boundary element method and finite difference method, have been used for years. However, such methods are computationally very expensive and make the computer...journal article 2024
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Mohammadi Gheidari, A. (author), Kieft, E. R. (author), Guo, X. (author), Wisse, M. (author), Kruit, P. (author)In the Multi beam source (MBS) of our Multi Beam Scanning Electron Microscope (MBSEM), an aperture lens array (ALA) splits the emission cone of the Schottky field emitter into multiple beamlets. When the apertures in the ALA are close to each other, the ALA can introduce aberrations to these beamlets through the electrostatic interaction of...journal article 2023
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Hesam Mahmoudi Nezhad, N. (author), Ghaffarian Niasar, M. (author), Hagen, C.W. (author), Kruit, P. (author)To design electron lens systems, applying a fully automated optimization routine has not yet been feasible, especially for the case where the optimization has many free variables of the lens system, such as all parameters that define the geometry of the lens electrodes and the voltage of each electrode. Hence, the study of the implementation of...conference paper 2023
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Hesam Mahmoudi Nezhad, N. (author), Ghaffarian Niasar, M. (author), Hagen, C.W. (author), Kruit, P. (author)The design of electrostatic electron lenses involves the choice of many geometrical parameters for the lens electrodes as well as the choice of voltages applied to the electrodes. The purpose of the design is to focus the electrons at a specific point and to minimize the aberrations of the lens. In a previous study, genetic algorithm...conference paper 2023
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Garming, M.W.H. (author), Kruit, P. (author), Hoogenboom, J.P. (author)Here, we demonstrate ultrafast scanning electron microscopy (SEM) for making ultrafast movies of mechanical oscillators at resonance with nanoscale spatiotemporal resolution. Locking the laser excitation pulse sequence to the electron probe pulses allows for video framerates over 50 MHz, well above the detector bandwidth, while maintaining...journal article 2022
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Krielaart, M.A.R. (author), Kruit, P. (author)We have analyzed the possibilities of wave front shaping with miniature patterned electron mirrors through the WKB approximation. Based on this, we propose a microscopy scheme that uses two miniature electron mirrors on an auxiliary optical axis that is in parallel with the microscope axis. A design for this microscopy scheme is presented for...journal article 2022
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Hesam Mahmoudi Nezhad, N. (author), Ghaffarian Niasar, M. (author), Mohammadi Gheidari, A. (author), Kruit, P. (author), Hagen, C.W. (author)The design of an electrostatic electron optical system with five electrodes and two objective functions is optimized using multiobjective genetic algorithms (MOGAs) optimization. The two objective functions considered are minimum probe size of the primary electron beam in a fixed image plane and maximum secondary electron detection efficiency...journal article 2021
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Turner, Amy E. (author), Johnson, Cameron W. (author), Kruit, P. (author), McMorran, Benjamin J. (author)Here, we experimentally demonstrate interaction-free measurements with electrons using a novel electron Mach-Zehnder interferometer. The flexible two-grating electron interferometer is constructed in a conventional transmission electron microscope and achieves high contrast in discrete output detectors, tunable alignment with independently...journal article 2021
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Hari, S. (author), Trompenaars, P. H.F. (author), Mulders, J. J.L. (author), Kruit, P. (author), Hagen, C.W. (author)High resolution dense lines patterned by focused electron beam-induced deposition (FEBID) have been demonstrated to be promising for lithography. One of the challenges is the presence of interconnecting material, which is often carbonaceous, between the lines as a result of the Gaussian line profile. We demonstrate the use of focused electron...journal article 2021
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Electrostatic electron mirror in SEM for simultaneous imaging of top and bottom surfaces of a sampleAbedzadeh, Navid (author), Krielaart, M.A.R. (author), Kim, Chung Soo (author), Simonaitis, John (author), Hobbs, Richard (author), Kruit, P. (author), Berggren, Karl K. (author)The use of electron mirrors in aberration correction and surface-sensitive microscopy techniques such as low-energy electron microscopy has been established. However, in this work, by implementing an easy to construct, fully electrostatic electron mirror system under a sample in a conventional scanning electron microscope (SEM), we present a...journal article 2021
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Krielaart, M.A.R. (author), Kruit, P. (author)Electron beams can be reflected by an electrode that is at a more negative potential than the cathode from which the beam is emitted. We want to design a mirror with a flat mirror electrode where the electrons are reflected at a plane very close to the electrode. The wave front of an electron can then be shaped when the mirror contains a...journal article 2021
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Zuidema, W. (author), Kruit, P. (author)Large area electron microscopy (EM) imaging has long been difficult due to fundamental limits in throughput for conventional electron microscopes. New developments in transmission electron microscopy and multi-beam scanning electron microscopy (MBSEM) imaging have however made it possible to generate large EM datasets [1,2,3]. This article...journal article 2020
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Jeevanandam, G. (author), van der Meijden, V. (author), Birnie, L. D. (author), Kruit, P. (author), Hagen, C.W. (author)To allow researchers to fabricate micro- and nano-devices on a small scale, without having to use complex cleanroom facilities, a single tool is proposed in which a variety of typical cleanroom techniques and processes is combined. This ‘cleanroom’ in SEM tool, based on a scanning electron microscope (SEM), integrates several add-on tools,...journal article 2020
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Krielaart, M.A.R. (author), Maas, D.J. (author), Loginov, S. (author), Kruit, P. (author)We designed and built a compact bi-axial electron beam separator. This separator is an indispensable electron optical element in the development of MEMS-mirror-based miniaturized concepts for quantum electron microscopy (QEM) and aberration-corrected low-voltage scanning electron microscopy (AC-SEM). The separator provides the essential...journal article 2020
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Hesam Mahmoudi Nezhad, N. (author), Ghaffarian Niasar, M. (author), Hagen, C.W. (author), Kruit, P. (author)In electron optics, the design of electron lens systems is still a challenge. To optimize such systems, the objective function which should be calculated, depends on the electric potential distribution in the space created by the lenses. To obtain the electric potential, the existing methods are generally based on some mathematical techniques...conference paper 2020
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Zhang, L. (author), Garming, M.W.H. (author), Hoogenboom, J.P. (author), Kruit, P. (author)Electrostatic beam blankers are an alternative to photo-emission sources for generating pulsed electron beams for Time-resolved Cathodoluminescence and Ultrafast Electron Microscopy. While the properties of beam blankers have been extensively investigated in the past for applications in lithography, characteristics such as the influence of...journal article 2020
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Garming, M.W.H. (author), Bolhuis, M. (author), Conesa Boj, S. (author), Kruit, P. (author), Hoogenboom, J.P. (author)Visualizing charge carrier flow over interfaces or near surfaces meets great challenges concerning resolution and vastly different time scales of bulk and surface dynamics. Ultrafast or four-dimensional scanning electron microscopy (USEM) using a laser pump electron probe scheme circumvents the optical diffraction limit, but disentangling...journal article 2020
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Zhang, L. (author), Hoogenboom, J.P. (author), Cook, B.J. (author), Kruit, P. (author)Observing atomic motions as they occur is the dream goal of ultrafast electron microscopy (UEM). Great progress has been made so far thanks to the efforts of many scientists in developing the photoemission sources and beam blankers needed to create short pulses of electrons for the UEM experiments. While details on these setups have typically...journal article 2019
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van Kessel, L.C.P.M. (author), Hagen, C.W. (author), Kruit, P. (author)Background: Monte Carlo simulations of scanning electron microscopy (SEM) images ignore most surface effects, such as surface plasmons. Previous experiments have shown that surface plasmons play an important role in the emission of secondary electrons (SEs).Aim: We investigate the influence of incorporating surface plasmons into simulations...journal article 2019
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Hesam Mahmoudi Nezhad, N. (author), Ghaffarian Niasar, M. (author), Mohammadi Gheidari, A. (author), Hagen, C.W. (author), Kruit, P. (author)In electrostatic charged particle lens design, optimization of a multi-electrode lens with many free optimization parameters is still quite a challenge. A fully automated optimization routine is not yet available, mainly because the lens potential calculations are often done with very time-consuming methods that require meshing of the lens...journal article 2019