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Preparation of sample cross-sections and analysis by SIMS
Karlovský, Juraj ; Pechal, Radim (referee) ; Bábor, Petr (advisor)
This thesis studies possible methods of semiconductor sample measurement by SIMS, with emphasis on testing different measurement parameters and sample preparation. Part of this master thesis deals with the design of a modified sample holder compatible with the used ToF-SIMS$^{5}$ instrument, IONTOF company, which is capable of tilting the sample by defined angle. This holder enables sample preparation in the main chamber of the instrument without the need of transferring the sample between instruments, which limits the probability of sample contamination. This sample holder was tested by ion machining of TIGBT sample edge and by imaging of a crater edge, created in previous measurement. Edge termination structures prepared by different techniques were measured on the TIGBT samples. Further measurements with the goal of optimizing the depth resolution for thin layers were done on Molybdenum-Silicon-multilayer X-Ray Mirror. Part of the measurements was focused on comparing depth profiles measured at low temperatures. For these measurements the samples with Indium multilayers in GaN substrate were used.
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Automation of dust charging experiment
Pechal, Radim ; Pavlů, Jiří (advisor) ; Žilavý, Peter (referee)
Title: Automation of dust charging experiment Author: Radim Pechal Department: Department of Surface and Plasma Science Supervisor: RNDr. Jiří Pavlů, PhD. Supervisor's e-mail address: Jiri.Pavlu@mff.cuni.cz Abstract: Since the dust grains are expected to cause problems during operation of tokamaks, there is a developing research of these devices which raises interest in dust grain charging processes research as well. Clarification of the dust grain charging processes may help with their solutions. This thesis deals with an issue of designing a part of a new experimental setup for dust grain research built at the Department of Surface and Plasma Science, Charles University in Prague. The base of this experimental setup is original linear quadrupole trap enabling dust grain trapping and its charging by electron, ion, and UV beams. In the thesis, a method of stabilization of one part of grain oscillation frequency detection is described. The thesis is focused on a development of a control unit and high voltage power supply for an image intensifier. To measure charging processes tungsten dust grains were used. This material will be probably used in construction of ITER tomakak. Electron equilibrium characteristics and other parameters were measured. Two samples of tungsten dust grains were used for...
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Preparation of sample cross-sections and analysis by SIMS
Karlovský, Juraj ; Pechal, Radim (referee) ; Bábor, Petr (advisor)
This thesis studies possible methods of semiconductor sample measurement by SIMS, with emphasis on testing different measurement parameters and sample preparation. Part of this master thesis deals with the design of a modified sample holder compatible with the used ToF-SIMS$^{5}$ instrument, IONTOF company, which is capable of tilting the sample by defined angle. This holder enables sample preparation in the main chamber of the instrument without the need of transferring the sample between instruments, which limits the probability of sample contamination. This sample holder was tested by ion machining of TIGBT sample edge and by imaging of a crater edge, created in previous measurement. Edge termination structures prepared by different techniques were measured on the TIGBT samples. Further measurements with the goal of optimizing the depth resolution for thin layers were done on Molybdenum-Silicon-multilayer X-Ray Mirror. Part of the measurements was focused on comparing depth profiles measured at low temperatures. For these measurements the samples with Indium multilayers in GaN substrate were used.
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Automation of dust charging experiment
Pechal, Radim ; Pavlů, Jiří (advisor) ; Žilavý, Peter (referee)
Title: Automation of dust charging experiment Author: Radim Pechal Department: Department of Surface and Plasma Science Supervisor: RNDr. Jiří Pavlů, PhD. Supervisor's e-mail address: Jiri.Pavlu@mff.cuni.cz Abstract: Since the dust grains are expected to cause problems during operation of tokamaks, there is a developing research of these devices which raises interest in dust grain charging processes research as well. Clarification of the dust grain charging processes may help with their solutions. This thesis deals with an issue of designing a part of a new experimental setup for dust grain research built at the Department of Surface and Plasma Science, Charles University in Prague. The base of this experimental setup is original linear quadrupole trap enabling dust grain trapping and its charging by electron, ion, and UV beams. In the thesis, a method of stabilization of one part of grain oscillation frequency detection is described. The thesis is focused on a development of a control unit and high voltage power supply for an image intensifier. To measure charging processes tungsten dust grains were used. This material will be probably used in construction of ITER tomakak. Electron equilibrium characteristics and other parameters were measured. Two samples of tungsten dust grains were used for...
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Analysis of multidimensional measurements of electromagnetic waves in the Earth's magnetosphere
Pechal, Radim ; Přech, Lubomír (advisor) ; Chum, Jaroslav (referee)
Title: Analysis of multidimensional measurements of electromagnetic waves in the Earth's magnetosphere Author: Radim Pechal Department: Department of Surface and Plasma Science Supervisor: doc. RNDr. Lubomír Přech, Dr. Supervisor's e-mail address: Lubomir.Prech@mff.cuni.cz Abstract: The thesis introduces into basic knowledge of waves in plasma, especially waves in the Earth's magnetosphere. There are mentioned some space projects focused on chorus waves. The second part of this thesis is a laboratory study of ELMAVAN device that is being developed within Resonance project. The main part of the thesis describes methods of onboard processing of measured LF electromagnetic field data and implementation of calculations in Field Programmable Gate Array. An important part of the thesis is a preparation of input data required for testing and verification of the FPGA program. Keywords: waves in plasma, chorus wave, Resonance project, ELMAVAN, FPGA
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