High field performance in reduced cross-sectional x-band waveguides made of different materials

RF breakdown is one of the major issues in the development of accelerating structures operated at high fields since the acceleration field is limited due to the metal surface damage [1, 2, 3]. RF breakdown studies are presently being carried out at Nextef (New X-band Test Facility at KEK) [4]. To study the characteristics of different materials on high-field RF breakdown we designed a reduced cross-sectional waveguide that has a field of approximately 200 MV/m at an RF power of 100 MW [5]. These type of waveguides are made of different materials such as copper (OFC), stainless steel, and molybdenum. This paper presents the first high-power test conducted on one of the copper waveguides.