Commissioning of the prototype C75 cavities in a CEBAF cryomodule

Conference · Sun Jul 01 04:00:00 EDT 2018

DOI:https://doi.org/10.18429/JACoW-IPAC2018-THPAL134· OSTI ID:1471388

Drury, Michael A. ^[1]; Cheng, Gary ^[1]; Ciovati, Gianluigi ^[1]; Daly, Ed F. ^[1]; Davis, G. Kirk ^[1]; Guo, Jiquan ^[1]; Legg, Robert A. ^[1]; Marhauser, Frank ^[1]; Powers, Thomas J. ^[1]; Reilly, Anthony V. ^[1]; Rimmer, Robert A. ^[1]

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

Prototype cavities have been built at Jefferson Lab to increase the energy of future refurbished CEBAF cryomodules to 75 MeV in the most cost efficient way. Three such cavities, named "C75", have been built from ingot Nb material of different purity and have been processed and tested. The two better performing cavities have been assembled into a "cavity pair" and installed in the latest refurbished original CEBAF cryomodule. The cryomodule was installed and commissioned in CEBAF. The results from the commissioning of the C75 cavities, compared with the original CEBAF cavities, are presented in this article. The vertical test performance of the C75 cavities was preserved in the cryomodule with one of the cavities achieving the performance specification of an accelerating gradient of 19 MV/m with a quality factor of ~8×109 at 2.07 K. The performance in terms of microphonics and tuner operation was similar to that of original CEBAF cavities, as expected, and the high-order modes are properly damped. The quality factor of the two C75 cavities was the highest achieved in a CEBAF cryomodule, possibly due to the better magnetic flux expulsion of ingot Nb than standard fine-grain Nb.

• Research Organization: Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
• DOE Contract Number: AC05-06OR23177
• OSTI ID: 1471388
• Report Number(s): JLAB-ACC-18-2713; DOE/OR/23177-4444
• Country of Publication: United States
• Language: English