Rampazzo V.

Paper	Title	Page
TUP33	Update on the JRA1 Project Results of Electro-Polishing of Multi-Cell Super Conducting Resonators	204
	N. Steinhau-Kuehl, R. Bandelmann, A. Matheisen, H. MoralesZimmermann, M. Schmoekel DESY Hamburg E. Palmieri, V. Rampazzo INFN
	Under the contract RII3-CT-2003-506395 of the European Union improvement on the electro-polishing (EP) of multi cell resonators are made. Several methods to improve resonator performances are studied. Improvement of electrode shape, simulated by numerical computer codes and test set ups are presented. With respect to reproducible cavity performances and industrialization of the EP process, a study for quality control by acid management is started. An automated EP system is developed at INFN Legnaro / Italy and within the collaboration of Legnaro and DESY this automated steering will be integrated into the DESY EP facility. We will report on the status of the WP 5.2.2.and the progress of the transfer of the automated EP.
WE203	The Progress on Nb3Sn and V3Si	392
	S. M. Deambrosis, N. Patron, A. Rossi, V. Palmieri INFN-LNL/Padua University G. Keppel, N. Pretto, V. Rampazzo, S. Stark, F. Stivanello INFN-LNL R. G. Sharma Inter-University Accelerator Centre
	In the framework of the research for a valid alternative to Nb for RF applications, Nb3Sn and V3Si have been investigated at LNL. The chosen technique to obtain Nb3Sn is based on the molten Tin diffusion method and it has been progressively modified to improve the samples superconducting properties (Tc and Delta Tc) and to eliminate Sn traces on the Nb3Sn surface. Our "Hybrid process" seems to be the most promising (Tc = 16,8 K and Delta Tc = 0,16 K, no residual Sn traces on the sample surface, no Sn rich phases). The present point is to test the obtained material RF properties: the best recipe used for samples has been applied to coat a 6 GHz Nb cavity. At the same time we are going to study different techniques to achieve Nb3Sn good superconducting cavities. One of them is the so called mechanical plating. Secondly we are going to study the multilayer technique: the first attempt gave a superconducting deposition with Tc = 17,9 K and Delta Tc =.0,02 (four contacts measurement). The V3Si intermetallic compound has been obtained using the thermal diffusion of Silicon into Vanadium: bulk V is heat treated in a SiH4 atmosphere for several hours and then annealed in vacuum. The samples superconducting properties are encouraging (Tc ~= 15,5 K and Delta Tc ~= 0,2 K). To check the material RF performances we prepared a V3Si 6 GHz cavity (sylanized for 4h at 850 degree C with p(SiH4) = 5x10-3 mbar): it has been measured several times after a heating treatment in vacuum progressively longer (6h, 12h, 36h, 84h at 850 degree C). At the moment, we are trying to use plasma during the silanization process to avoid the hydrogen presence into the growing films. The first V3Si coating grown has Tc = 15,7 K and Delta Tc = 0,22 K: this result is already comparable to what we had with the "traditional" technique.
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