• Z.A. Conway, E.P. Chojnacki, D.L. Hartill, G.H. Hoffstaetter, M. Liepe, H. Padamsee, A. Romanenko, J. Sears
  CLASSE, Ithaca, New York

Cornell University’s superconducting cavity development program is one contributor to the global collaborative effort on critical SRF R&D for the ILC. We conduct R&D in support of the baseline cavity development as well as several alternate cavity development paths. For the baseline program we are preparing and testing ILC cavities. We have developed a new quench detection system and successfully applied it to ILC 9-cell and 1-cell cavities to find quench producing defects, which were characterized with subsequent optical examination. We have successfully repaired a 9-cell cavity using tumbling to raise the accelerating gradient from 15 to above 30 MV/m. We have identified quench producing defects in single-cell cavities using our large-scale thermometry system and subsequently extracted and inspected the defect region with an SEM. For the alternate R&D, we are developing reentrant cavity shapes with 70 mm and 60 mm apertures, and a simpler, potentially faster and less expensive electropolishing method called vertical electropolishing. We are also assisting in developing new cavity vendors by rapidly testing single-cell cavities they produced to qualify their fabrication methods.

• E.P. Chojnacki, R.D. Ehrlich, M. Liepe, J. Sears, E.N. Smith
  CLASSE, Ithaca, New York

Broadband RF absorbing materials are frequently utilized in particle accelerator environments. There are stringent requirements placed on some of these absorbers in regard to vacuum compatibility, radiation compatibility, and particulate generation, especially for absorbers in close proximity to the beamline such as in some higher order mode (HOM) load designs. For RF absorbers located directly on the beamline, their DC conductivity must also be large enough to drain away static charge that may be deposited onto them, since such static charge could deflect the particle beam. Ceramics and ferrite materials have often been used for such RF absorbers, and SRF applications tend to extended their use to cryogenic temperatures. Unfortunately, the DC conductivity of these materials often drops precipitously with temperature and they become excellent insulators at cryogenic temperatures. The results of recent DC conductivity tests of several of these RF absorbing materials will be presented.

• P.A. McIntosh, R. Bate, C.D. Beard, S.M. Pattalwar
  STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
• S.A. Belomestnykh, E.P. Chojnacki, Z.A. Conway, G.H. Hoffstaetter, P. Quigley, V. Veshcherevich
  CLASSE, Ithaca, New York
• A. Büchner, F.G. Gabriel, P. Michel
  FZD, Dresden
• M.A. Cordwell, D.M. Dykes, J. Strachan
  STFC/DL, Daresbury, Warrington, Cheshire
• J.N. Corlett, D. Li, S.M. Lidia
  LBNL, Berkeley, California
• T. Kimura, T.I. Smith
  Stanford University, Stanford, Califormia
• S.R. Koscielniak, R.E. Laxdal
  TRIUMF, Vancouver
• M. Liepe, H. Padamsee, J. Sears, V.D. Shemelin
  Cornell University, Ithaca, New York
• D. Proch, J.K. Sekutowicz
  DESY, Hamburg

The collaborative development of an optimised cavity/cryomodule solution for application on ERL facilities has now progressed to final assembly and testing of the cavity string components and their subsequent cryomodule integration. This paper outlines the testing and verification processes for the various cryomodule sub-components and details the methodology utilised for final cavity string integration. The paper also highlights the modifications required to integrate this new cryomodule into the existing ALICE cryo-plant facility at Daresbury Laboratory.