Wakefield and HOMs preliminary characterization of the four-quadrant multi-cell RF accelerating structure for the ASTERIX project

The goal of the ASTERIX project, proposed at INFN-LNF and funded by the CSN5, is the first-time demonstration of a practical, meter-long X-band RF structure for real linear accelerators made of hard copper and four quadrants. Our joining technique will be the TIG welding for the prototype. During the feasibility study, in the first year, we will proceed to the RF cavity design of two full structures (~ 1m long and ~100 cells), one with optimized geometry for single-bunch and the other one for multi-bunch operation. We will perform the RF design optimization, including thermo-mechanical analysis, of the multi-cell TW cavity and the RF mode-launcher (which will be integrated with the cavity in the most compact way possible) for both structures’ geometries. In this paper, we show the preliminary characterization of the higher-order modes (HOMs) and wake-fields, which are detrimental for the particle beam with high-quality parameters typically accelerated in such structures, in the case of single-bunch operation. The electromagnetic designs will be performed by using the 3D numerical codes Ansys-HFSS and CST-Microwave Studio.