Status of the CERN-Karlsruhe superconducting particle separator

The present status of the rf separator is given, and measurements of single cavity sections and of two joined sections are reported. The problem of storing heat treated sections until final assembly was investigated. Flooding a cavity at room temperature with nitrogen deteriorates its performance, after the cavity was once excited to a peak electric field of 30 MV/m, corresponding to a peak magnetic field of 850 G and a deflecting field of 5.5 MV/m. This effect is assumed to be due to a sensitization of the surface oxides by field emission electrons. The effect is not observed after an electric field of up to 15 MV/m, and it also does not appear when the cavity is flooded with argon. (auth)