• Z.A. Conway, E.P. Chojnacki, D.L. Hartill, M. Liepe, D. Meidlinger, H. Padamsee, J. Sears, E.N. Smith
  CLASSE, Ithaca, New York

Funding: Work Supported by the NSF and the DOE

An innovative reentrant cavity design instigated the initial, highly successful, superconducting niobium reentrant-single-cell cavity tests at Cornell and KEK. Prompted by the success of the single cell program a joint effort of Cornell University and Advanced Energy Systems (AES) fabricated two multiple-cell reentrant cavities: a three-cell and a nine-cell cavity. This paper reports the development status of these two cavities. First, the results of cold tests, superfluid helium defect location and repair work on the reentrant nine-cell cavity will be presented. Second, the results of cold tests, including defect location and repair efforts of the reentrant three-cell cavity will be presented.

• D. Meidlinger, E.P. Chojnacki, H. Padamsee
  CLASSE, Ithaca, New York

Funding: National Science Foundation

Diagnosing field-limiting behavior in multi-cell superconducting cavities can be difficult due to the lack of direct local measurements of cavity surface properties. The results of multiple vertical tests on several 5-cell vertically electropolished 1.3GHz superconducting cavities with measurements of cavity surface properties are presented. A combination of oscillating superleak transducer and resistive thermometry data for various accelerating passband modes are used to infer the field-limiting mechanism for several cells of each multi-cell cavity.