Design and cold test of a novel waveguide power splitter for distributed power coupling in short-pulse acceleration

RF breakdown is the major limitation to achieving higher accelerating gradients. Recent experimental evidence shows that this limitation can be mitigated by reducing the RF pulse length to a few nanoseconds. One key challenge in designing an accelerator operating in the short-pulse regime is achieving the required short filling time. In this work, we designed a novel waveguide power splitter to independently feed an array of accelerating cells. A prototype X-band waveguide array for a one-to-four power splitter has been developed to drive standing-wave cavities operating in the short-pulse regime. The power is designed to be equally split and fed into four cavities, with the desired phase advance per cavity. A 3D-printed prototype has been used for low-power microwave measurements ("cold" tests). The results, including measurements with a vector network analyzer and time-domain measurements, show good agreement with simulations. Ongoing work includes designing a multi-cell accelerator based on this concept for two-beam acceleration with few-nanosecond RF pulses.