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Coulomb interactions in electron beams
Jánský, Pavel
The paper describes numerical calculations of thermionic electron gun of an electron-beam welding machine and optimization of its electron optical system. It describes new method used in program EOD for determination of space-charge effect on emitted current and on electron trajectories in the gun.
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Micro-machining by an electron beam
Zobač, Martin
The work deals with problems of removing material with an intensive electron beam (EB) in vacuum. The main goal is study of the interaction of EB with metallic and possibly non-metallic materials. An undividable part of the work is a preparation of an experimental device, its experimental parts and the electron gun. It will be necessary to create a unique electronics, especially a HV source enabling impulse operation of the electron gun.
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Coulombian interactions in ion beams
Jánský, Pavel
The work deals with computations and optimization of electron(ion)-optical systems, in which the action of spatial charge asserts significantly. The programs CPO and EOD are used for computer simulations. The optimization of geometry of the nozzle of the electron welder is the first of solved tasks.
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A new construction of rotor of helium expansion turbine
Dupák, Jan ; Hanzelka, Pavel ; Michalička, Petr ; Tuček, L. ; Ustohal, V.
The aim of our work was to develop a rotor of the expansion turbine designed for a helium liquefier that would enable operation in different modes and achieving of the desired effectiveness at same time. For meeting theserequirements the rotor should enable precise operation of the turbine in the range of 140 000 to 350 000 rqm at minimum heat flow to the low-temperature part of the turbine. Considering the low thermal conductivity and a high strength, the low-temperature part was made of VT3-1 titanium alloy. This contribution is focused mainly on problems of creation of mechanically strong and thermally resistant joint of this part of the rotor with the part working at room temperature.
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