Abstract
The paper is concerned with the laboratory metallurgical installation designed for heat treatment and zone melting of refractory metals without a crucible. A 10kW electron-beam gun serves as a heater. The installation is evacuated from the atmospheric pressure to the ultimate vacuum using cryopumps only. Particular attention is given to hydrogen pumping. Performances of helium adsorption and condensation cryopumps with an efficiency up to 10 4/s −1 for hydrogen have been studied experimentally. The consumption of liquid helium was found to be 40–50cm 3 h −1 for adsorption pumps and 7cm 3h −1 for condensation pumps. It is shown that the application of the condensation pump with a surface cooled down to 2.3 K seems to be most efficient.
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