High-Gradient Test Results of W-Band Accelerator Structures

We report initial high-gradient testing results of a 110 GHz single-cell standing wave accelerating cavity powered by a 1 MW gyrotron. The cavity is fed with 10 ns, 100s of kilowatt pulses, and achieved a field gradient up to 225 MV/m. We also report the observation of rf breakdowns and cavity processing for $\lt /p\gt \gt 10 ^{5}$ pulses.