• T. Abe, T. Kageyama, H. Sakai, Y. Takeuchi, K. Yoshino
  KEK, Ibaraki

A damping ring of positron beams is under consideration for the upgrade of KEKB (SuperKEKB) because low emittance of beams injected to the main rings is required by the SuperKEKB optics in the nano-beam scheme. We present the design of the RF accelerating structure, especially on the higher-order-mode (HOM) damped structure. This structure is based on the normal-conducting accelerating cavity system ARES, which has successful records of the long-term stable operations so far with low trip rates at KEKB. All the HOM absorbers are made of silicon carbide, bullet-shaped, and to be directly water cooled, so that the structure presented in this paper can be also a prototype for accelerating beams of the order of 10A in the SuperKEKB main ring in the high-current scheme.