Impact of remanent magnetic field on the heat load of original CEBAF cryomodule
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
The heat load of the original cryomodules for the CEBAF accelerator is ~50% higher than the target value of 100 W at 2.07 K for refurbished cavities operating at an accelerating gradient of 12.5 MV/m. This issue is due to the quality factor of the cavities being ~50% lower in the cryomodule than when tested in a vertical cryostat, even at low RF field. Previous studies were not conclusive about the origin of the additional losses. We present the results of a systematic study of the additional losses in a five-cell cavity from a decommissioned cryomodule after attaching components, which are part of the cryomodule, such as the cold tuner, the He tank and the cold magnetic shield, prior to cryogenic testing in a vertical cryostat. Flux-gate magnetometers and temperature sensors are used as diagnostic elements. Different cool-down procedures and tests in different residual magnetic fields were investigated during the study. Here, three flux-gate magnetometers attached to one of the cavities installed in the refurbished cryomodule C50-12 confirmed the hypothesis of high residual magnetic field as a major cause for the increased RF losses.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Nuclear Physics (NP)
- Grant/Contract Number:
- AC05-06OR23177
- OSTI ID:
- 1338913
- Report Number(s):
- JLAB-ACC-16-2339; DOE/OR/23177-3942; TRN: US1701227
- Journal Information:
- IEEE Transactions on Applied Superconductivity, Vol. 27, Issue 4; ISSN 1051-8223
- Publisher:
- Institute of Electrical and Electronics Engineers (IEEE)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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