• M.P. Kelly, S.M. Gerbick
  ANL, Argonne
• D.R. Olis, A.M. Rowe
  Fermilab, Batavia

New SRF cavity processing systems at ANL, including those for electropolishing (EP), high-pressure water rinsing (HPR), and single-cavity clean room assembly have been developed and operated at ANL for use with cavities for a range of electron and ion linac applications. Jointly with FNAL, systems for 1.3 GHz single- and multi-cell elliptical cavities for the linear collider effort have been developed. New systems for use with low-beta TEM-class cavities have also been built and used to process a set of new quarter-wave resonators as part of an upgrade to the ATLAS heavy-ion accelerator at ANL. All of the new hardware is located in a 200 m2 joint ANL/FNAL Superconducting Cavity Surface Process Facility (SCSPF) consisting of two separate chemical processing rooms, a clean anteroom, and a pair of class 10 and 100 clean rooms for HPR and clean assembly. Results of first cold tests for elliptical and TEM-class cavities processed in these facilities are presented.

• M.H. Foley, T.T. Arkan, H. Carter, H.T. Edwards, J. Grimm, E.R. Harms, T.N. Khabiboulline, D.V. Mitchell, D.R. Olis, T.J. Peterson, P.A. Pfund, N. Solyak, D.J. Watkins, M. Wong
  Fermilab, Batavia
• G. Galasso
  University of Udine, Udine

Funding: This work was supported by Fermilab Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The 3.9 GHz 3rd harmonic cavities are designed to serve as compensation devices for improving the longitudinal emittance of the free-electron laser FLASH at DESY. These cavities operate in the TM010 mode, and will be located between the injector and the accelerating cavities. Fermilab is obligated to provide DESY with a cryomodule containing four 3rd harmonic cavities. In this paper we discuss the process of welding helium vessels to these cavities. Included will be a description of the joint designs and weld preparations, development of the weld parameters, and the procedure for monitoring the frequency spectrum during TIG welding to prevent the cavity from undergoing plastic deformation. Also discussed will be issues related to qualifying the dressed cavities as exceptional vessels (relative to the ASME Boiler and Pressure Vessel Code) for horizontal testing and eventual installation at DESY, due to the necessary use of non-ASME code materials and non-full penetration electron beam welds.

• E.R. Harms, T.T. Arkan, V.T. Bocean, H. Carter, H.T. Edwards, M.H. Foley, T.N. Khabiboulline, M.W. McGee, D.V. Mitchell, D.R. Olis, A.M. Rowe, N. Solyak
  Fermilab, Batavia

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Fermilab is involved in an effort to design, build, test and deliver four 3.9 GHz superconducting rf cavities within a single cryomodule to be delivered to DESY as a 'third harmonic' structure for the FLASH facility to improve the longitudinal emittance. In addition to an overall status update we will present recent results from single 'dressed' cavity horizontal tests and shipping and alignment measurements.

Slides