High-Gradient Accelerator in the mm-Wave Regime*

We present the design of a high gradient accelerator operating at 94 GHz. Simulations of the cavity geometry and RF coupling network are performed in ANSYS-HFSS and using SLAC's parallel electromagnetic code suite ACE3P. The distributed coupling topology enables optimization of the individual cell geometry, including reentrant nose cones, to achieve a high shunt impedance exceeding 400 MΩ/m. Using cryogenic cooling to liquid nitrogen temperatures, we expect a normal conducting cavity, fabricated from copper, would approach a shunt impedance of 1 GΩ/m. We discuss the design challenges for accelerators operating in the mm-wave regime, as well as the potential advantages for applications requiring ultra-compact structures. We also report on progress made in prototype fabrication.