• B. van der Horst, A. Matheisen, B. Petersen, M. Schmoekel, N. Steinhau-Kuehl, H. Weitkaemper
  DESY, Hamburg

Within the last decade the production and preparation of superconducting resonators became more and more stable at DESY. Two cycles for the final surface preparation, the final surface removal by electro polishing (EP) and the final surface removal by a short buffered chemical polishing (BCP flash) are the baseline of cavity surface preparation at DESY. Basing on the positive development overtime and in view of industrialization of the processes for the XFEL project, a proposal for a reduced number of work steps was presented on the SRF 2007 workshop in Beijing [1]. Two parallel preparation lines, the final EP and BCP flash line, are tested on 15 cavities, for each line since. The cavities were produced by two different suppliers and randomly distributed to the preparation lines. In addition two industrial suppliers started industrialized electro polishing facilities for the main surface removal by electro polishing (main EP.) We present the cavity test results for the two preparation cycles.

• N. Steinhau-Kuehl, A. Matheisen
  DESY, Hamburg
• T. Eidtner, C. Hartmann, B. Henkel
  Henkel, Neustadt-Glewe

Electro-polishing has become one of the leading surface preparation processes to reach high gradients in superconducting cavities. For industrialization and for reproducible results in the electro-polishing process a study on acid quality control and quality management was launched under the scope of the European investigations under the CARE. First results of this acid management studies were presented at the TTC meeting 2006 and the JRI-SRF summary reports 2008. A second study with experimental results on the quality control methods proposed was launched where the different methods and instrumentations for acid quality control are studied in detail. We present the results of this following up investigations made on acid quality control for the electro-polishing mixture applied at DESY.