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Title: High current RF shield for PEP-II vacuum system expansion joint

Conference ·
OSTI ID:632501

A novel RF shield was developed for the circular expansion joint used throughout the PEP-II vacuum system straight sections. Existing RF shield designs, used in accelerators/storage rings throughout the world, have been the source of many failures at beam currents much smaller than the 3 amps planned for PEP-II. This RF shield uses a unique spring-loaded finger mechanism to maintain proper electrical contact across the joint, accommodate 1.5 mm transverse and 32 mm longitudinal excursions, while minimizing geometry-driven trapped-mode RF heating at GHz frequencies. Alumina-dispersed, copper alloy fingers are used to maintain desired mechanical properties at higher temperatures instead of the more commonly used beryllium-copper alloys. A prototype expansion joint was assembled, mechanically tested, and subjected to 200% of the expected operational RF load. This RF shield design can be easily adapted to non-circular geometries.

Research Organization:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
632501
Report Number(s):
UCRL-JC-124099; CONF-960621-; ON: DE98051114; TRN: 98:008899
Resource Relation:
Conference: EPAC `96: 5. European particle accelerator conference, Barcelona (Spain), 10-14 Jun 1996; Other Information: PBD: 1 May 1996
Country of Publication:
United States
Language:
English