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Electron optical properties of a new low-energy scanning electron microscope with beam separator
Radlička, Tomáš ; Kolařík, V. ; Oral, Martin
The low energy scanning electron microscope (SEM) which is currently at the Institute of\nScientific Instruments, suffers from low resolution and suboptimal detections systems. In the cathode lens regime, signal electrons are accelerated by the electric field between the sample and the objective lens, getting collimated. Those with low emission angles get through the bore in the BSE detector into the objective lens and cannot be detected by the available detectors now. The information about the sample provided by these electrons is lost, which limits our microscopy methods.\nThese two limitations are to be overcome with a new low-energy SEM, which was developed\nat Delong Instruments. It consists of a field emission gun with the energy width of 0.8 eV, a magnetic condenser lens, and an electrostatic triode objective lens. The acceleration voltage is 5 kV. The sample stage can be biased at up to -5 kV to provide low landing energy without strong decrease of the resolution – the effect of the cathode lens. A beam separator is placed in front of the deflection system for the detection of the signal electrons that get to the column. In a combination with standard detectors and cathode lens, it allows detecting all\nkinds of signal electrons.
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Very low energy electron transmission spectromicroscopy
Daniel, Benjamin ; Radlička, Tomáš ; Piňos, Jakub ; Mikmeková, Šárka ; Konvalina, Ivo ; Frank, Luděk ; Müllerová, Ilona
For more than 25 years, Scanning Low Energy Electron Microscopy (SLEEM) has been\ndeveloped at the Institute of Scientific Instruments (ISI), with several commercially available SEMs adapted with a cathode lens for SLEEM use, as well as a dedicated self-built UHVSLEEM setup.\nFor a better understanding of contrast formation at low energies, especially at very low energies below 50 eV, where the local density of states plays an important role, more general knowledge about the interaction of (very) low energy electrons with solids is required. This will be achieved using a newly developed ultra-high vacuum (UHV SLEEM) setup which includes several enhancements compared to other available machines. Data processing is presented in, and processed data will be further used and tested with the Monte Carlosimulation package BRUCE, which is being developed by Werner et al. at TU Vienna.
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Characterization of industrial materials by slow and very slow electrons
Mikmeková, Šárka ; Müllerová, Ilona ; Frank, Luděk
Progress in materials science and engineering is inseparably connected with excellent knowledge of the correlation between materials properties and their microstructure. In our experiment an ultra-high vacuum scaning low energy electron microscope (UHV SLEEM) of an in-house design was used to observe microstructure of specimens. The UHV SLEEM is equipped with the cathode lens (CL) assembly, which enables us to observe samples at arbitrary landing energies of primary electrons. The device provides argon ion beam for in-situ cleaning of the specimen surface.
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