EP Activities under Care WP 5 Surface preparation

EP Activities under Care WP 5 Surface preparation L. Lije CEA Saclay C. Antoin INFN Legnaro E. Palmierie DESY Hamburg A. Matheisen EP on samples and single-cells Optimized EP parameters Automated EP EP on multi cells A very short overview on the meeting at Legnaro TTC meeting Frascati Dec. 05 A. Matheisen DESY

Equipment for WP 5. 1 CEA Saclay • U/ I test cells • studies on fixed and rotating samples • Surface analysis • Various method's • Roughness etc. in collaboration with partner institutes • Surface reflectivity • gloss measurement • chromatography for analysis of acid • Single cell test bench TTC meeting Frascati Dec. 05 A. Matheisen DESY

CARE-SRF : Work package 5 -1 : Optimization of EP Optimization of Electropolishing Bench test for monocells Samples studies : aging, impurities, cathode corrosion Application to scale 1 (non trivial) 1 rst results => present used conditions = not always optimal ! TTC meeting Frascati Dec. 05 A. Matheisen DESY

TTC meeting Frascati Dec. 05 A. Matheisen DESY

Single cell test bench TTC meeting Frascati Dec. 05 A. Matheisen DESY

WP 5. 3 automated EP TTC meeting Frascati Dec. 05 A. Matheisen DESY

TTC meeting Frascati Dec. 05 A. Matheisen DESY

Cells with different cathode geometries . . . two mounths ago distribution Current distribution Flat cathode Shaped cathode Magnetic field distribution Line-scan Magnetometry demonstrates Frascati Dec. 05 shaped cathode that the TTC meeting A. Matheisen DESY guarantees a better elettropolishing than the flat cathode!

TTC meeting Frascati Dec. 05 A. Matheisen DESY

Work point of DESY EP TTC meeting Frascati Dec. 05 Influence on EP Parameters (Measurement at DESY) A. Matheisen DESY

TTC meeting Frascati Dec. 05 A. Matheisen DESY

EP on multi cells at DESY • improved gas cleaning operational easy to handle • Clear base line design for lab EP set up • Application on industrial infrastructure needs discussion • Hot water rinsing Needs studies on single cells • Application on multi cells at DESY is cost intensive and needs more space in EP facility TTC meeting Frascati Dec. 05 A. Matheisen DESY

Ep parameters Bath aging --- Bath mixture TTC meeting Frascati Dec. 05 A. Matheisen DESY EP Parameter 17 V

EP mixture at 20°C, HF-content given in percentage of new mixture 1/9 TTC meeting Frascati Dec. 05 A. Matheisen DESY

change in current by reduction of HF content at 30°C DESY EP parameter Reduction of removal rate TTC meeting Frascati Dec. 05 A. Matheisen DESY

Refreshment of acid 1/9 starting from used (50% HF content) acid TTC meeting Frascati Dec. 05 A. Matheisen DESY

Status • • • Aging effects are observable: Loss of HF? ? U/I Set up System operational and in use for QC Parameters reproducible in lab set up Clear temperature dependency on U/I found Online parameters need to be corrected for T. (T Compensation needed) Online probe installed in DESY EP apparatus Operational beginning of O 6 U/I Control Allows predictions on stable operation of EP (Current and removal rate)! Not sensitive for changes in Acid mixture! (See HF problem Aug 05)! Only limited application for QC QC of EP acid No correlation found for cavity performance / Q problem! TTC meeting Frascati Dec. 05 A. Matheisen DESY

Optimization on electrode shape • Detailed look at the electrode shape – Computer software installed and operational – Personnel training done – Input data not complete yet Data on the DESY EP acid under measurement – It is feasible to check other electrolytes with software • Laser roughness measurement – Underway at Wuppertal University TTC meeting Frascati Dec. 05 A. Matheisen DESY

For more details and discussion see CARE homepage http: //jra-srf. desy. de/ Meetings/ Legnaro Or contact Clair Antoin Enzo Palmierie Lutz Lilje A. Matheisen TTC meeting Frascati Dec. 05 A. Matheisen DESY