High gradient mm-wave metallic accelerating structures

We are exploring the physics of vacuum rf breakdowns in high gradient metallic accelerating structures at sub-THz frequencies. We present the experimental results of rf tests performed in beam-driven travelling-wave accelerating structures. We measured the breakdown rates, the frequency of the emitted radiation, and the gradients. As the next step in this study, we are developing accelerating structures powered by an rf source. We report on the status of this project.