RF breakdown studies in X-band klystron cavities

RF breakdown studies are presently being carried out at SLAC with klystron cavities in a traveling wave resonator (TWR). Different kinds of fabrication methods and several kinds of semiconducting and insulating coatings have been applied to X-Band TM/sub 010/ cavities. RF breakdown thresholds up to 250 MV/m have been obtained. Dark current levels were found to be depressed in TiN-coated and single-point diamond turned cavities. A new TM/sub 020/ cavity with demountable electrodes has been designed and will be used to test a variety of materials, coatings, and processes. Recent tests of klystron output windows at 119 MW are also presented in this paper.