CEBAF`s SRF cavity manufacturing experience
- Continuous Electron Beam Accelerator Facility, Newport News, VA (United States)
Construction of the Continuous Electron Beam Accelerator Facility (CEBAF) recirculating linac represents the largest scale application of superconducting rf (SRF) technology to date. The accelerating structures in CEBAF are 169 pairs of 1.5 GHz superconducting rf cavities -- 9 pairs in an injector and 80 pairs each in two linacs. The beam is to be recirculated up to five passes through each linac. Data is presented on mechanical tolerances achieved by the industrial fabricator of the rf cavities (Siemens). Liquid helium leak rates integrated over 22 vacuum seals have been measured on over 110 cavity pairs. A roughly normal distribution of the log{sub 10} (leak rate) is seen, centered about a rate of 10{sup {minus}10.4} torr-l/s. Over 140 pairs of the cavities have been assembled and have completed rf testing at 2.0 K. Among these, 54% demonstrated usable accelerating gradients greater than 10 MV/m. Although the rf performance characteristics well exceed the CEBAF baseline requirements of 5 MV/m at Q{sub 0} = 2.4{times}10{sup 9}, the usual limiting phenomena are encountered: field emission, quenching, and occasional multipacting. A discussion of the occurrence conditions and severity of these phenomena during production cavity testing is presented. The frequency with which performance is limited by quenching suggests that additional material advances may be required for applications which require the reliable achievement of accelerating gradients of more than 15 MV/m.
- OSTI ID:
- 45728
- Report Number(s):
- CONF-930703-; TRN: 94:007382-0045
- Resource Relation:
- Conference: International cryogenic materials conference (ICMC), Albuquerque, NM (United States), 12-16 Jul 1993; Other Information: PBD: 1994; Related Information: Is Part Of Advances in cryogenic engineering, Volume 39, Part A; Kittel, P. [ed.]; PB: 1038 p.
- Country of Publication:
- United States
- Language:
- English
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