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Analysis of active material for batteries by EDS
Vídeňský, Ondřej ; Jaššo, Kamil (referee) ; Čudek, Pavel (advisor)
This master thesis deals with analysis of battery mass using x-ray spectral microanalysis. For the measurement two scanning electron microscopes equipped with energy dispersive x-ray spectroscopes were used. Appropriate examples were prepaired by standard method. Then elemental analysis was performed with changing conditions of measurement. Two programs were used for spectrums evaluation and in the end the size of errors was observed for every conditions.
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Scintillation Secondary Electrons Detector for ESEM
Čudek, Pavel ; Kadlec, Jaromír (referee) ; Rek, Antonín (referee) ; Jirák, Josef (advisor)
The thesis deals with the scintillation secondary electron detector for environmental scanning electron microscope, its design and construction. The starting point was numerical simulation of electrostatic fields and electron trajectories in the electrode system of the detector and simulation of pressure distribution and flow of gases in different parts of the detector. On the basis of modeling and simulation, construction changes of the detector were gradually implemented. Detection efficiency of each version of the detector was determined by the method described in the work. This method enables to evaluate signal level from the captured images of the specimen, quality of images was stated from signal to noise ratio. The thesis describes the whole process of the detector improvement from initial state, when the detector operated with lower efficiency in the pressure range from 300 to 900 Pa, to final version that enables usage of the detector in the range from vacuum up to 1000 Pa of water vapors in the specimen chamber of the microscope.
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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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Ionization detector for environmental scanning electron microscope
Melechovský, Ondřej ; Čudek, Pavel (referee) ; Jirák, Josef (advisor)
Presented work deals with environmental scanning electron microscopy. The construction of the device is described concisely in the beginning. Important part is devoted to interaction of electrons with specimen and signals emitted from the specimen. The work aims especially at detection of secondary electrons using the ionization detector. Experimentally is determined effect of working environment and size of electrode system of ionization detector on detected signal.
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Influence of working conditions on the signal level detected by BSE detector
Bednář, Eduard ; Zimáková, Jana (referee) ; Čudek, Pavel (advisor)
This thesis deals with the evaluation of the quality of the signal level of backscattered electrons detected by the scintillation backscattered electron detector depending on the working conditions in low vacuum scanning electron microscope. The theoretical part describes the issue of environmental scanning electron microscopy, the principle of generation the signal and detection of backscattered electrons. The experimental part of the thesis is to measure the properties of the scintillation detector of backscattered electrons. A series of experiments is evaluated the influence of working conditions on the stability and function of the detector of backscattered electron.
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Characteristics of semiconductor BSE electron microscope detector
Plot, Vítězslav ; Hubálek, Jaromír (referee) ; Boušek, Jaroslav (advisor)
The thesis deals with the characterization of a semiconductor detector of backscattered electrons. The theoretical part describes two types of electron microscopes, the interaction of the primary beam with the sample and individual types of electrons and radiation arising during the interaction. The most used types of electron detectors in scanning electron microscope are summarized. The basic characteristics of the semiconductor backscattered electron detector and their measurement methods are described. The experimental part deals with measuring the characteristics of the detector made by Delong Instruments and comparing it with commercially available detectors. Volt-ampere characteristic and dark current, the dependence of the gain on the accelerating voltage, as well as the time response of the detector were measured.
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Analysis of active material for batteries by EDS
Vídeňský, Ondřej ; Jaššo, Kamil (referee) ; Čudek, Pavel (advisor)
This master thesis deals with analysis of battery mass using x-ray spectral microanalysis. For the measurement two scanning electron microscopes equipped with energy dispersive x-ray spectroscopes were used. Appropriate examples were prepaired by standard method. Then elemental analysis was performed with changing conditions of measurement. Two programs were used for spectrums evaluation and in the end the size of errors was observed for every conditions.
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Ionization detector for environmental scanning electron microscope
Melechovský, Ondřej ; Čudek, Pavel (referee) ; Jirák, Josef (advisor)
Presented work deals with environmental scanning electron microscopy. The construction of the device is described concisely in the beginning. Important part is devoted to interaction of electrons with specimen and signals emitted from the specimen. The work aims especially at detection of secondary electrons using the ionization detector. Experimentally is determined effect of working environment and size of electrode system of ionization detector on detected signal.
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