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Design and verification of low temperature parts of UHV SEM/SPM stage
Pola, Tomáš ; Vlček, Ivan (referee) ; Urban, Pavel (advisor)
This thesis focuses on experimental verification and experimental-based improvements of designed low temperature parts of stage of the UHV SEM/SPM microscope, which operates in temperature range from 20 K to 700 K. The main focus is on the functionality verification of thermal insulation pad (InBallPad) as well as on the effect of length and contact quality of braid on minimal achievable temperature. The contact quality of sample holder with sample carrier realized with two springs is investigated together with influence of thermal contact resistances on achievable temperature. The thesis also contains a calculation model used for cooldown times and minimal temperature estimation. In the conclusion of this work several future experiments are suggested which could explain some of the observed, yet unexpected, phenomena.
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Materials and their application in low temperature parts of STM microscope
Voňka, Jakub ; Vlček, Ivan (referee) ; Urban,, Pavel (advisor)
Průtokvý kryostat s kapalným héliem (LHe) je vyvíjen skupinou Kryogeniky a Supravodivosti na Ústavu Přístrojové Techniky pro stávající rastrovací tunelovací mikroskop (STM) pracující za pokojové teploty na Ústavu Fyzikálního Inženýrství. Tato bakalářská práce se zabýva výběrem materiálů a určením jejich vlastností pro potenciální využití v některých částech nízkoteplotního STM mikroskopu (LT-STM), se zaměřením zejména na tepelnou vodivost v teplotním rozsahu od 4 K do 300 K. Je zde probírána problematika měděných svazků pro tepelné spojení vzorku s tepelným výměníkem. Slitina CuCrZr byla podrobně zkoumána jako vhodný materiál pro držák vzorku. Byly určeny tepelné toky málo vodivými podpěrami založenými na styku sférických ploch pro použití jako izolace mezi studeným držákem vzorku a STM stolkem.
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SMV-2015-10: Development of the electron gun for welding of the radioactive samples
Zobač, Martin ; Vlček, Ivan
The subject of the project was the research and development of the electron gun for electron beam welding with accelerating voltage 60 kV and maximal power 2 kW. The device was developed for work in so called "hot chamber", where it is exposed to radioactive radiation. The project was characteristic by solving complex problems from different fields and resulted in construction of functional prototype, that was successfully tested in cooperation with the client.
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SMV-2015-09: Development of welding of zirconium alloy
Zobač, Martin ; Vlček, Ivan
The subject of the project was further research and development of permanent joints of zirconium alloys by electron beam welding for the needs of the nuclear industry. The outcome of the project were specific technological procedures for the given assemblies verified by test series. The significant experimental demands were characteristic for this project.
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SMV-2015-08: Research and development of electric vacuum connector
Zobač, Martin ; Vlček, Ivan
The subject of the project was further research and development of the multi-pin electric vacuum connector. The outcome of the project was design layout of the connector and the technology to produce glass seals, resulting in realization. These produced connectors were successfully tested. The need to solve strong influence of some technological steps on final parameters of glass seals.
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