Diagnosis, Analysis, and Resolution of Thermal Stabliity Issues with HOM Couplers on Prototype CEBAF SRF Cavities.

Wu, C. ; Preble, J. ; Wang, H. ; Phillips, H. ; Hicks, W. ; Reece, C.

Technical Information Center Oak Ridge Tennessee

关键词: CEBAF accelerator;    Superconducting cavity resonators;    Thermodynamics;    Stability;    Thermal efficiency;   

RP-ID  :  DE2008923384

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

During initial testing of the prototype cavities incorporated into the developmental cryomodule Renascence severe thermal stability issues were encountered during CW operation. Additional diagnostic instrumentation was added. This enabled identification of an unanticipated thermal impedance between the HOM coupler probe feedthrough assembly and the cavity beamtube. Subsequent detailed FE analysis successfully modeled the situation and indicated the need for alternate cooling path for the couplers on those cavities. HOM damping was measured to be adequate employing only two of the four HOM couplers. The two pickup probes on the couplers at the input power coupler side of each cavity were removed, the remaining HOM probe feedthroughs were heat stationed to two-phase helium supply piping, and a novel heat sink was added to station both the inner and outer conductors of the remaining HOM rf cables. The characterization measurements, analysis, modifications, and resulting performance are presented.