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Concept and Development of Single-purpose Scanning Electron Microscope
Foret, Zdeněk ; Vašina, Radovan (referee) ; Starý,, Vladimír (referee) ; Svoboda, Milan (referee) ; Švejcar, Jiří (advisor)
Electron microscopy has become an essential component in many scientific fields, in which it contributes to new discoveries. The microscopy itself is continually being developed and the limits, which seemed to be insurmountable, have been overcome. The instruments have become user friendlier and their mobility enables flexible practical use in the field. The subject of this work is the design of a scanning electron microscope, the calculation of a magnetic curcuit of an immersion objective combined with standard lens, the theoretical calculation of a microscope resolution and the design solution of the mechanical parts of the microscope with a sample manipulator. The thesis includes a description of the electron microscopy development summarizing it briefly from the very beginning up to now. It also deals with electron sources, especially the Shottky cathode, which is to be the main object observed by the proposed device. The work also contains a description of the calculation of the microscope resolution as a function of the current density distribution. Another interesting issue included in the theoretical part is the signal detection, a description of several types of detectors and possible signal processing. The solution of the thesis includes a description of the concept of the scanning electron microscope with an explanation of the distribution of combined lens functions. The optical diagram shows the arrangement of the electron optics system and the distibution of pressure in the chamber of the microscope. The theoretical calculation is devoted to the magnetic curcuit design of the objective and to the resolution of the microscope for a given extent of working distances. Two modifications of the lens were designed – a standard simple objective and a combination of the standard objective with the immersion magnetic one. The results of both modifications are given for the parameters to be compared. The combined objective was designed with the possibility of use in two modes, as a standard and immersion lens. The deflection system is also divided into two modes, as a single deflection for the standard lens and as a two-dimension deflection for the immersion lens. Detectors for secondary electrons (SE) and detectors for back scattered electrons (BSE) will be used for the signal detection. The design of the microscope is another large part, which gives details on the most significant components of the microscope. The content of the technical solution is a three-dimensional computer model, created in Autodesk Inventor, which also includes a sample manipulator driven by piezoelectric actuators.
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Concept and Development of Single-purpose Scanning Electron Microscope
Foret, Zdeněk ; Vašina, Radovan (referee) ; Starý,, Vladimír (referee) ; Svoboda, Milan (referee) ; Švejcar, Jiří (advisor)
Electron microscopy has become an essential component in many scientific fields, in which it contributes to new discoveries. The microscopy itself is continually being developed and the limits, which seemed to be insurmountable, have been overcome. The instruments have become user friendlier and their mobility enables flexible practical use in the field. The subject of this work is the design of a scanning electron microscope, the calculation of a magnetic curcuit of an immersion objective combined with standard lens, the theoretical calculation of a microscope resolution and the design solution of the mechanical parts of the microscope with a sample manipulator. The thesis includes a description of the electron microscopy development summarizing it briefly from the very beginning up to now. It also deals with electron sources, especially the Shottky cathode, which is to be the main object observed by the proposed device. The work also contains a description of the calculation of the microscope resolution as a function of the current density distribution. Another interesting issue included in the theoretical part is the signal detection, a description of several types of detectors and possible signal processing. The solution of the thesis includes a description of the concept of the scanning electron microscope with an explanation of the distribution of combined lens functions. The optical diagram shows the arrangement of the electron optics system and the distibution of pressure in the chamber of the microscope. The theoretical calculation is devoted to the magnetic curcuit design of the objective and to the resolution of the microscope for a given extent of working distances. Two modifications of the lens were designed – a standard simple objective and a combination of the standard objective with the immersion magnetic one. The results of both modifications are given for the parameters to be compared. The combined objective was designed with the possibility of use in two modes, as a standard and immersion lens. The deflection system is also divided into two modes, as a single deflection for the standard lens and as a two-dimension deflection for the immersion lens. Detectors for secondary electrons (SE) and detectors for back scattered electrons (BSE) will be used for the signal detection. The design of the microscope is another large part, which gives details on the most significant components of the microscope. The content of the technical solution is a three-dimensional computer model, created in Autodesk Inventor, which also includes a sample manipulator driven by piezoelectric actuators.
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