HIGH ORDER MODES SURVEY AND MITIGATION OF THE CEBAF C100 CRYOMODULES

Conference · Tue Jul 01 04:00:00 EDT 2014

DOI:https://doi.org/10.18429/JACoW-IPAC2014-WEPRI073· OSTI ID:1968811

Wang, Shaoheng ^[1]; Guo, Jiquan ^[1]; Wang, Haipeng ^[1]; Stirbet, M. ^[1]

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1. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

Ten new C100 cryomodules have been fabricated and installed for the CEBAF 12 GeV upgrade in the past few years. The high order modes (HOM) of these modules need to be controlled to avoid beam breakup (BBU) instability. Over the last few years, we surveyed the HOM for all the 80 cavities of the C100 modules in the Vertical Test Area (VTA), as well as in the JLAB Cryomodule Test Facility (CMTF) and the CEBAF tunnel. Additional measures such as waveguide filters were applied to reduce the quality factor of the out of spec modes. In addition, we also measured the same passband modes of all the cavities. In this paper, we will present the HOM survey methodology and results from CMTF and CEBAF survey (not including the VTA survey), as well as the same passband modes. The mitigation measures and their effects will also be discussed.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 1968811
• Report Number(s): JLAB-ACC-14-1915; DOE/OR/23177-3395
• Country of Publication: United States
• Language: English