A SW Ka-Band linearizer structure with minimum surface electric field for the compact light XLS project

There is a strong demand for accelerating structures able to achieve higher gradients and more compact dimensions for the next generation of linear accelerators for research, industrial and medical applications. In the framework of the Compact Light XLS project, an ultra-high gradient higher harmonic RF accelerating structure is needed for the linearization of the longitudinal phase space. In order to determine the maximum sustainable gradients in normal conducting RF powered particle beam accelerators with extremely low probability of RF breakdown, investigations are in progress for using short accelerating structures in the Ka-band regime. We here report an electromagnetic design of a compact linearizer standing wave (SW) accelerating structure. The cavity has a length of about 8 cm and operates on the π-mode at 35.982 GHz, which is the third harmonic with respect to the Linac frequency (11.994 GHz). The accelerating gradient is 100 MV/m and the cavity geometry is optimized in order to minimize the surface peak electric field.