Basic studies for the electro polishing facility at DESY

At DESY a TESLA test facility is operating since 1994. In this facility the cavity preparation bases on the application of buffered chemical polishing (BCP). From the results of the RF measurements it can be deduced that this preparation technique reaches a limitation at acceleration voltage of 30 MV/m. To exceed these values to the region of 40 MV/m an electro polishing system will be added to this facility (see this conference). In order to get the official permission ('Betriebs-genehmigung') by the German administration some basic in formation about the processes have to be studied. We report on measurements of samples which will give information on aging of the acid and the parameters like removal rates, polishing effect, out gassing of H2 and O2 correlated to this. On a test single cell an analysis of the amount and concentration of the gas development during the process will be studied. We report on parameter settings for the polishing process. (author)