Design of the RF waveguide network for the klystron-based CLIC main linac RF module

Abstract

The klystron-based Compact Linear Collider (CLIC) was initially proposed with a low center-of-mass energy of 380 GeV, primarily due to potential cost-effectiveness. To enhance overall cost-efficiency, reliability, and stability, a novel RF module for klystron-based CLIC main linac has been designed and studied. This RF module utilizes two X-band klystrons to feed eight traveling wave accelerating structures, resulting in a beam energy increase of 138 MeV. A key innovation of the new RF module is the integration of double-height waveguides, which contributes to a 30% reduction in surface fields and a 40% decrease in RF loss. To meet the double-height requirement, a majority of the RF components responsible for transmitting the high RF power underwent a redesign. Two solutions, based on the choke mode flange and the L-shape waveguide, were proposed to facilitate the adjustment of the accelerating structures for beam-based alignment. Additionally, bent damping waveguides and HOM loads and a high order Magic-T, were designed for the accelerating structure named CLIC-K. The paper will comprehensively present and describe both the RF design and the integration of the klystron-based CLIC module.