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Modular Monte Carlo Simulation Including Secondary Electron Raytracing
Gnieser, D. ; Frase, C. G. ; Bosse, H. ; Konvalina, Ivo ; Müllerová, Ilona
A Monte Carlo simulation program for the modeling of image formation in scanning electron microscopy is presented. A key feature of the program is its modular design, so the different aspects of image formation (i.e. forming of the electron probe, specimen topography model, probe-sample-interaction, electron detector model, image processing) are arranged in separate program modules. The program is written in C++ and uses object-oriented programming techniques. Data exchange between the different program modules is performed by defined software interfaces. Thus, third party simulation code can easily be integrated into the program.
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Vyšší řády derivací pole ve výpočtu aberací
Radlička, Tomáš
The aberration coefficients are important optical characteristics of the electron optical system. The third order aberrations are well known but the calculation of the fifth order aberrations is an object of recent research. This contribution is focused on marginalized part of these calculations – the calculation of analytical expansion of the field near the axis.
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Řešení složitých elektronově optických problémů v EOD
Lencová, Bohumila
The paper summarizes the possibilities of accurate computation of potential with the first order finite element method and highly accurate ray tracing in numerically computed fields, which were implemented in the EOD program. The use of the program is illustrated on the results of computation of third order aberration coefficients of an electrostatic mirror and by the computation of correctors of axial aberrations of electron microscopes.
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Detekce signálu v rastrovacím elektronovém mikroskopu pomocí detektorů sekundárních elektronů
Konvalina, Ivo ; Hovorka, Miloš ; Dvořáková, Marie ; Müllerová, Ilona
The collection of secondary electrons (SE) was studied for microscopes where the magnetic field penetrates to the specimen surface and for the arrangement with the specimen region free of magnetic field. Collection efficiency of secondary electron detectors varies with their energy and angular sensitivity connected with electrostatic and magnetic field distribution in the specimen region which influences the contrast of SE images. The trajectories of SE with regard to their energy, angular distributions are simulated and secondary electron detectors compared on the basis of calculated collection efficiency. For the verification of the simulated data the standard resolution-testing specimen with Au particles on a carbon substrate was used.
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Měření elektronově-optických vlastností Wienova filtru stínovou metodou
Horáček, Miroslav ; Vlček, Ivan ; Zobač, Martin
Wien filter is suitable for the separation of the primary and the signal electron beams in very low energy scanning electron microscope with cathode lens. We have modified the two-grid shadow method to determine experimentally electron optical properties (cardinal elements and aberrations) of the Wien filter, which is not a rotationally symmetric element. We call the modified method the shadow method with grid and moving screen. The advantage of the shadow method is its geometrical simplicity allowing the comparison of the experimentally obtained and numerically computed trajectories.
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Prevence tvorby uhlovodíkové kontaminace v SEM
Dvořáková, Marie ; Mika, Filip
Electron beam-induced contamination is one of the most undesirable effects in SEM. In this work the contamination was formed on silicon wafer, copper, aluminium, stainless plate and nickel samples. The contamination was removed by the plasma cleaning (XEI Scientific Evactron De-Contaminator).
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