Qualification and Cryogenic Performance of Cryomodule Components at CEBAF
At CEBAF an electron beam is accelerated by superconducting resonant niobium cavities which are operated submerged in superfluid helium. The accelerator has 42 1/4 cryomodules, each containing eight cavities. The qualification and design of components for the cryomodules under went stringent testing and evaluation for acceptance. Indium wire seals are used between the cavity and helium vessel interface to make a superfluid helium leak tight seal. Each cavity is equipped with a mechanical tuner assembly designed to stretch and compress the cavities. Two rotary feedthroughs are used to operate each mechanical tuner assembly. Ceramic feedthroughs not designed for superfluid were qualified for tuner and cryogenic instrumentation. To ensure long term integrity of the machine special attention is required for material specifications and machine processes. The following is to share the qualification methods, design and performance of the cryogenic cryomodule components.
KeywordsSuperfluid Helium Mechanical Tuner Window Assembly Helium Vessel Electrical Feedthrough
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- 1.J. Brawley, F. Folsom, S. Morgan, B. Jones, R. Bennett, and C. Reece, CEBAF experience with in-house fabrication of niobium parts, Proceedings of the 6th Workshop on RF Superconductivity, Oct., 1993, Vol. II.Google Scholar
- 2.M. G. Rao, High sensitivity He desorption leak detection method, J. Vac. Sci. Technical, A (4), Jul/Aug 1993, 1993 American Vacuum Society.Google Scholar
- 3.M. Wiseman, et al., Cryobench — Apparatus for Testing CEBAF Cryogenic Subcomponents, Applications of Cryogenic Technology, Vol. 10., 1991Google Scholar
- 4.E. Folts, A history of production cryomodule tuners, March 22, 1995.Google Scholar
- 5.D. Henkel, Report on the investigation of vacuum leakage in the CEBAF cavity pair bellows assembly, a report prepared for CEBAF by the NDE Lab. of NASA Langley Research Center, 11/27/92.Google Scholar
- 6.W. Schneider, private communication.Google Scholar
- 7.D. Henkel, Ref. 5.Google Scholar
- 8.W. Schneider, Review recommendations re: charge to working group I: flange and seal modification, memo to F. Dylla, July 3, 1991.Google Scholar