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Actively Cooled RF Power Coupler : Theoretical and Experimental Studies
In cryostats for Super-conducting Radio Frequency Cavities, the heat loads introduced by the high-power RF couplers represent an important fraction of the overall static thermal budget. Working at low operating temperature benefits from a reduced surface resistance (low dynamic losses) but is penali...
Autores principales: | , |
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Lenguaje: | eng |
Publicado: |
2014
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Materias: | |
Acceso en línea: | http://cds.cern.ch/record/2062594 |
Sumario: | In cryostats for Super-conducting Radio Frequency Cavities, the heat loads introduced by the high-power RF couplers represent an important fraction of the overall static thermal budget. Working at low operating temperature benefits from a reduced surface resistance (low dynamic losses) but is penalized by the high refrigeration cost. The external conductor of RF coaxial couplers provides a direct conduction path from ambient to cryogenic temperature plus is heated by resistive power deposition. Heat interception is therefore essential to contain heat in-leaks: a double-walled external conductor with a properly designed gas cooling effectively reduces heat loads to the cold bath by 1 order of magnitude. This paper presents the thermal design of the RF power coupler of the Superconducting Proton Linac (SPL) at CERN, featuring a helium vapour cooling between 4.5 K and ambient temperature. Numerical models, which can be used as design tools for other applications, have been developed to assess efficiency and thermal performance. A full-size mock-up cooled by nitrogen has been built for experimental validation. Comparison between calculations and measurements is presented and discussed. |
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