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Photo-Hall effect spectroscopy and laser-induced transient currents in CdTe-based semiconductor radiation detectors
Musiienko, Artem ; Grill, Roman (advisor) ; Dubecký, František (referee) ; Oswald, Jiří (referee)
Title: Photo-Hall effect spectroscopy and laser-induced transient currents in CdTe-based semiconductor radiation detectors Author: Artem Musiienko Department / Institute: Institute of Physics, Faculty of Mathematics and Physics, Charles University Supervisor of the doctoral thesis: Prof. RNDr. Roman Grill, CSc, Institute of Physics, Faculty of Mathematics and Physics, Charles University Abstract: Cadmium Telluride, Cadmium Zinc Telluride, and Cadmium Manganese Telluride are important semiconductors with applications in radiation detection, solar cells, and electro-optic modulators. Their electrical and optical properties are principally controlled by defects forming energy levels within the bandgap. Such defects create recombination and trapping centers capturing photo- created carriers and depreciating the performance of the detector. Simultaneously, the changed occupancy of levels leads to the charging of detector's bulk, which results in the screening of applied bias and the loss of detector's sensitivity. Detailed knowledge of crystal defect structure is thus necessary for the predictable detector work and also for the possibility to reduce the structural defects concentration. This thesis reports on the investigation of deep energy levels in CdTe-based high resistivity and detector-grade materials by...
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Investigation of high voltage influence on different materials in high and low vacuum
Šedivý, Matúš ; Šandera, Josef (referee) ; Hejátková, Edita (advisor)
The beginning of this thesis contains an overview of properties of the insulators, and description of insulators that were used for in depth research of surface breakdown in vacuum. Furthermore, this work focuses on mechanisms of an electric breakdown initiation at the interface of the solid insulator and surrounding low pressure gas. Multiple methods for measurements of dielectric strength are examined. The experimental part describes the measurements performed in the vacuum chamber. The results of these measurements are then analysed. In conclusion, used insulators are compared and suggestions for further work are given.
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Additives effect on electrical properties of the epoxy resins
Šebesta, Petr ; Kazelle, Jiří (referee) ; Frk, Martin (advisor)
Work was carried out in collaboration with SYNPO, Inc. Pardubice, which provided samples resins with various additives for measurement. The work is divided into three theoretical and one practical chapters. The first chapter focuses on dielectrics in general. It deals with their properties and storyline running in them. The second chapter discusses epoxy resins, their formulation, production and application in manufacturing. The third chapter offers a view of the measurement methods used for diagnosing electrical dielectrics. The practical part describes the preparation of samples and their composition, and consequently their measurement with the evaluation of measurement data.
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Analysis of the Profile Busbar Conductors Properties
Domes, František ; Novotný, Jan (referee) ; Orságová, Jaroslava (advisor)
Checking of busbar system against effects of short circuit currents and currents of regular operation is important because of safety and also economic reasons. This Bachelor’s thesis deals with calculation of heating of belt conductor during the operation. There are also calculated mutual power effects between belt conductors and checking of busbar system on heat and power effects of short circuit current during the operation. Practical part includes the design of belt line of cell substation. Calculation was made by software Microsoft Excel.
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