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Influence of experimental chamber pumping on gas temperature
Balobanov, Damir ; Bílek, Michal (referee) ; Maxa, Jiří (advisor)
The master‘s thesis is focused on issue of pumping in the experimental pumped chambre of an environmental scanning microcope. In the theoretical part, there are presented microscopy as science. Afterwards the thesis is focused on electron microscopy and its problem and vakuum system, computer program used for preparation of simulation and study that the experimental part is based on. The experimental part contains the results of gas flow in the differential pumped chambre. The problematics were solved by Ansys Fluent system.
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Analysis of the dimensions of pumping channels in a new design of a scintillation detector
Kryll, Josef ; Bílek, Michal (referee) ; Maxa, Jiří (advisor)
The aim of this thesis is to study the issue of eniveromental scanning electron microscopy and pumping gas to create a vacuum in the newly designed scintillation detector. Further, creating a model of recently proposed scintillation detector and simulating and analyzing pumping gas in differentially pumped chamber of detector and the results compare with the previous model. The theoretical part deals with electron microscopy, electron sources, electron optics and secondary electrons detectors. It is also presented which signals are generated by the electron beam on the surface of a solid. Further fluid flow issues and equations describing the flow in the solved chamber are dismantled. Furthermore, the impact of gaseous environment on the trajectory of primary electrons, because there are collisions of primary beam with atoms and molecules of gas. The following section discusses creating, quality and importance of the network in mathematical modelling. A method of a final volume used to calculate the differential equations describing the flow of gas at the premises of the microscope is described . The practical part consists in creating a model of scintillation detector and analyzing the gas flow in drawing a vacuum in the newly designed scintillation detector. Furthermore, the simulation results are compared with the results of simulations on the older type of scintillation detector. The output of this thesis is model of recently proposed scintillation detector with visualized simulation results.
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Influence of nozzle angle on gas pressure distribution in the nozzle according to Prandtl's theory
Dostalová, Petra ; Maxa, Jiří (referee) ; Šabacká, Pavla (advisor)
The thesis is focused on issue pressure distribution in the nozzle while pumping the differential pumped chambre of an environmental scanning microcope. The main task of the thesis is to find suitable design of this nozzle respect to Prandtl`s theory. In the theoretical part, there are presented microscopy as science. Afterwards the thesis is focused on environmental scanning electron microscopy and its problem and vacuum system, computer program used for preparation of simulation and study that the experimental part is based on. The experimental part evaluates the results of physical-mathematical analysis of the flow inside and behind the Laval nozzle in the experimental chambre. The results are the basis for the optimal proportions of this nozzle.
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Influence of experimental chamber pumping on gas temperature
Balobanov, Damir ; Bílek, Michal (referee) ; Maxa, Jiří (advisor)
The master‘s thesis is focused on issue of pumping in the experimental pumped chambre of an environmental scanning microcope. In the theoretical part, there are presented microscopy as science. Afterwards the thesis is focused on electron microscopy and its problem and vakuum system, computer program used for preparation of simulation and study that the experimental part is based on. The experimental part contains the results of gas flow in the differential pumped chambre. The problematics were solved by Ansys Fluent system.
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Pumping analysis in the experimental chamber for electron microscope using ANSYS system
Dostalová, Petra ; Bílek, Michal (referee) ; Maxa, Jiří (advisor)
The thesis is focused on issue of pumping in the differential pumped chambre of an environmental scanning microcope. In the theoretical part, there are presented microscopy as science. Afterwards the thesis is focused on environmental scanning electron microscopy and its problem and vakuum system, computer program used for preparation of simulation and study that the experimental part is based on. The experimental part contains the results of gas flow in the differential pumped chambre. The problematics were solved by Ansys Fluent system.
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FLOW ANALYSIS OF THE PRESSURE IN THE EXPERIMENTAL CHAMBER OF THE DIFFERENTIAL PUMPING
Šabacká, Pavla ; Bílek, Michal (referee) ; Maxa, Jiří (advisor)
The thesis deals with the effect of the critical flow, which is produced at pumping of the differential pumping chamber of the Environmental Scanning Electron Microscope (ESEM). The thesis compares the state of the flow in the area of pumped chamber at pressure ratio on the apertures when the critical flow occurs and its advantages in design of the chambers versus the flow without the clogging the nozzle. Problematics were solved using finite volume method by Ansys Fluent system.
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Analysis of the impact of the conic aperture placement in the supersonic flow in the differentially pumped chamber
Rous, Miroslav ; Bílek, Michal (referee) ; Maxa, Jiří (advisor)
The thesis is focused on the medium dynamics simulation in the environmental scanning electron microscope. Specifically, it researches (examines) the conical aperture location effect in the differential pumped chamber and the width of the pumping channel in this chamber. The theoretical part deals with the environmental scanning microscope generally and other tools used in this thesis, e.g. ANSYS Fluen software, fluid turbulence, medium free path of molecules and electrons scattering. In the practical part, the work is focused on data processing from the ANSYS Fluent program and on their evaluation.
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Mathematical-physical analysis of dynamic pressure for the experimental differentially pumped chamber
Lepltová, Kristýna ; Bílek, Michal (referee) ; Maxa, Jiří (advisor)
This thesis is based on the series of scholarly article dedicated to the issue of pumping in the differential scanning chamber of an environmental scanning microscope. The thesis is based on Danilatos’s study where the pumping of the differential pumped chamber is solved by means of the Monte Carlo statistical method. The thesis analyzes gas flow in the experimental chamber using the Pipot tube. The analyses will be used for the design of the experimental chamber which will serve for the experimental evaluation of the flow results in the chamber using the continuum mechanics.
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Specifications of the Ansys Fluent Solution Solver for low pressures in EREM
Šimík, Marcel ; Bílek, Michal (referee) ; Maxa, Jiří (advisor)
This thesis is focused on electron microscopy which issue is discussed at the beginning of work. The main attention is dedicated to the Environmental electron microscope, especially the differentially pumped chamber, which the thesis deals with. There is a production of an experimental chamber for analysis of shock waves on going therefore main goal of this thesis was to analyze the flow pattern in this chamber. Using the Ansys Fluent program, simulations of the characteristic flow that arises from the pumping of the vacuum chambers namely the ultrasonic flow at low pressures on which the most suitable turbulent module was applied as well as the degree of discretization was performed. The final analysis of this flow pattern is primarily focused on the localization of the shock wave which experimental evidence is to be lodged by shadow optical method as a part of the new concept of the chamber. The basis for the simulation of the chamber was taken over by Dr. Danilatos, with which the results were compared.
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