• Z.A. Conway, E.P. Chojnacki, D.L. Hartill, M. Liepe, H. Padamsee, J. Sears
  CLASSE, Ithaca, New York
• M.S. Champion, G. Wu
  Fermilab, Batavia

Funding: Work Supported by the U.S. Department of Energy

To build the ~14,000 cavities required for the ILC each of the three world regions must have a sizable industrial base of qualified companies to draw cavities from. One of these companies, Niowave Inc., recently manufactured six 1.3 GHz single-cell cavities for qualification purposes. All six cavities achieved gradients above 25 MV/m before they were limited by the available RF power (Q-slope) or quenched. This paper will report the results of cold tests for all six cavities and on the causes of quench determined by 2nd sound detection and optical inspection.

• L. Cooley, D. Burk, M.H. Foley, D.T. Hicks, R. Schuessler, C. Thompson, G. Wu
  Fermilab, Batavia

Combined temperature mapping and optical inspection of SRF cavities has revealed defects near the edge of the heat affected zone (HAZ) of numerous welds. We have re-created similar defects on welded coupons that were electropolished in the lab and characterized by a variety of tools. Several features that may have bearing on the origin of these defects are discussed, such as their location relative to grain boundaries, the strain state of the niobium prior to welding and etching, the electropolishing parameters, and so forth. Since coupons are useful for distribution to academic researchers, we also describe other detailed characterizations.