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Scintillation SE Detector with Controlled Gas Flow for VP SEM
Kozák, Josef ; Neděla, Vilém (referee) ; Jirák, Josef (advisor)
This master’s thesis deals with a design and optimization of an experimental scintillation secondary electron detector for the environmental scanning electron microscope and with a description of a detector operation principle. The experiment is founded on simulations of a gas flow in detector inner sections and on simulations of secondary electron trajectories in electrostatic fields of the detector. On the basis of the simulations, new solutions of the detector designs are proposed. For these designs, same simulations as previous are performed and designs that seem to be feasible for the secondary electron detection in environmental scanning electron microscope are selected.
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Scintillation SE Detector for Variable Pressure SEM
Tihlaříková, Eva ; Neděla, Vilém (referee) ; Jirák, Josef (advisor)
This project deals with the theme of environmental scanning electron microscopy (EREM). This method allows the examination of insulators and wet specimens without pretreatment and modification like drying and metallization. The principle of this method consists in using higher pressure in a specimen chamber. The pressure is within the range of 100 – 200 Pa. However, the pressure in the specimen chamber restricts the signal detection interference. The objective of the work is to explore the possibility of interference in secondary electron route detection by way of electrostatic field. The electrostatic field was realized with the system consisting of four electrodes located in front of the scintillation detector. It should have interfered the secondary electron´s trajectory to the detector chamber. The optimization of voltage on the electrodes was made by simulation program called SIMION. The simulation results were experimentally verified with laboratory EREM.
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Optimization of scintillation detector for detection of low energy signal electrons in electron microscopy
Tihlaříková, Eva ; Kadlec, Jaromír (referee) ; Uruba, Václav (referee) ; Neděla, Vilém (advisor)
The dissertation thesis deals with optimization of the scintillation detector for efficient detection of low energy signal electrons in a specimen chamber of a scanning electron microscope. The solution was based on the study of signal electron energy loss mechanisms during their interaction with a conductive layer and a scintillator that can be studied using simulations based on the stochastics Monte Carlo methods. Based on test simulations and their comparison with experimental data, the ideal Monte Carlo software was chosen and used for the study of signal electron energy losses during their transport through the conductive layer as well as following interaction with scintillator, in dependency on the signal electron energy. Simulation results allowed to define criteria for the optimization of the conductive layer. According to these parameters, the optimized layers were deposited on the surface of different scintillators and experimentally tested in the scintillation detector of the scanning electron microscope. Experimental measurements allowed to verify accomplished simulations and provide new information about impact of materials and thicknesses of conductive layers in combination with materials of scintillators and light guides. The increase of the detection efficiency of the scintillation detector equipped with optimised conductive layers and its capability to detect low energy signal electrons were experimentally proved.
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Application of Environmental Scanning Electron Microscopy (ESEM) in the field of miniatures´ analysis: methodology for specific use in miniature painting research
Hradil, David ; Hradilová, J. ; Neděla, Vilém ; Tihlaříková, Eva
The methodology deals with a completely new, unused procedure of non-invasive analysis of painted portrait miniatures, namely an environmental scanning electron microscope with energy-dispersive X-rays. spectrometer(EREM-EDS). EREM, unlike the conventional scanning electron microscope (REM), allows the analysis of ivory painting, which is not possible in a vacuum or low gas pressure environment, where there is a risk of deformation and damagedue to drying of this biological material. The methodology is divided into two parts - the first describes the study of morphological details at high magnification (eg. the possibility of distinguishing different types of biological substrates), the second is the implementation of elemental analysis in high spatial resolution.
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SMV-2021-06: EDS analysis of industrial samples
Neděla, Vilém ; Tihlaříková, Eva
The user workshop aimed at handling of the software Esprit 2.2. functioning as a component part of X-Ray EDS analyzer (firm Bruker). The workshop includes the practical demonstrations of elements analyses of samples specially chosen by customer. Further, the workshop is aimed at the basic routines of the morphological analysis of these samples by means of scanning electron microscope.
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SMV-2021-05: CLSM of miniature painting
Neděla, Vilém ; Olbert, Martin
The samples were analyzed in the confocal laser scanning microscope equipped with the special sample holder for gripping of miniatures compatible with electron microscope. The surface microstructure as well as the individual coloured zones of the samples were analyzed.
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Aplikace environmentální rastrovací elektronové mikroskopie (EREM) v oboru analýzy miniatur: metodika pro specifické použití ve výzkumu miniaturního malířství
Hradil, David ; Hradilova, Janka ; Neděla, Vilém ; Tihlaříková, Eva
The methodology deals with a completely new, unused procedure of non-invasive analysis of painted portrait miniatures, using environmental scanning electron microscope with an energy-dispersive X-ray spectrometer (ESEM-EDS). ESEM, unlike the conventional scanning electron microscope (SEM), allows the analysis of the painting on the ivory support, which is not possible in the gas pressure approaching the vacuum, where there is a risk of deformation and damage due to the drying of this biological material. Instead of an inert gas (nitrogen, argon), the aim is to use a mixture of nitrogen and water vapor at a defined pressure corresponding to the required relative humidity in the measuring chamber. This enables a completely non-invasive analysis of painted miniature objects on organic types of supports. This methodology is divided into two parts: morphological analysis and elemental composition analysis. The first case involves the study of morphological details at high magnification (e. g. the possibility of distinguishing different types of supports or characterizing their microstructure). The second part describes the implementation of elemental analysis in high spatial resolution (distinction of individual pigment grains).
Fulltext:  PDF; PDF
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