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Multi-electrode system of ionization detector for environmental scanning electrone microscope
Uhlář, Vít ; Špinka, Jiří (referee) ; Jirák, Josef (advisor)
Thesis deals with environmental scanning electron microscopy and with detection of signal electrons by using ionization detector. First part talks about the principle of environmental scanning electron microscope. Second part describes signals generated by interaction of primary electron beam with sample. Third section explains the principle of impact ionization and ionization detector. Experimental part deals with usage of segmental ionization detector and with measuring of signal amplification from copper and platinum. Thesis also examines arrangement of electrodes of ionisation detector on material contrast and examines also on influence of voltage contrast on base - emitter junction of an NPN bipolar transistor. All experiments were carried out in dependency on saturated water vapour pressure in sample chamber.
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Multi-electrode system of ionization detector for environmental scanning electrone microscope
Uhlář, Vít ; Špinka, Jiří (referee) ; Jirák, Josef (advisor)
Thesis deals with environmental scanning electron microscopy and with detection of signal electrons by using ionization detector. First part talks about the principle of environmental scanning electron microscope. Second part describes signals generated by interaction of primary electron beam with sample. Third section explains the principle of impact ionization and ionization detector. Experimental part deals with usage of segmental ionization detector and with measuring of signal amplification from copper and platinum. Thesis also examines arrangement of electrodes of ionisation detector on material contrast and examines also on influence of voltage contrast on base - emitter junction of an NPN bipolar transistor. All experiments were carried out in dependency on saturated water vapour pressure in sample chamber.
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Ionization detector for ESEM
Pokluda, Tomáš ; Špinka, Jiří (referee) ; Jirák, Josef (advisor)
This thesis is focused on the environmental scanning electron microscopes including a description of the basic physical mechanisms. It describes the design and realization of the electrode ionization detector system suitable for the detection of signal electrons with a greater proportion of secondary electrons. It also deals with simulations of trajectories of electrons in the electrostatic field of the detector, and with verification of the functionality of the detector in the environment of water vapors in the specimen chamber of the electron microscope.
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Contrast in image acquired by ionization detector in VP SEM
Goroš, Pavel ; Čudek, Pavel (referee) ; Jirák, Josef (advisor)
This work deal with problems of investigation materials electron beam. This project is focuses on investigation materials by the help of method environmental scan electron microscopy (ESEM) and describes her patterns. The perfection of ESEM excel above all at studies non - conducting or water containing, often biological samples. These samples not to be in no way prepared or cut – and – dries, in contradistinction to classical scanning electron microscope and thanks is under investigation their native surface structure without desiccation breaking. The general aim is determination of contrast in image acquired by ionization detector.
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Method of Voltage Contrast in ESEM
Buchta, Michal ; Černoch, Pavel (referee) ; Jirák, Josef (advisor)
This graduation thesis deals with the problem of voltage contrast in ESEM. The purpose of this work was to verify influence of used detectors in the dependence on conditions in specimen chamber on the size of voltage contrast. With the conditions in specimen chamber we understand pressure and working conditions of signal detection. We used power transistor as specimen.
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