A TM020-mode cavity with choke geometry for Super Tau-Charm Facility

To meet the requirements of collider rings of Super Tau-Charm Facility (STCF) with a beam current of up to 2 A, a TM020-mode cavity with improved performance is designed in this paper. In order to address the issues of leakage of accelerating mode into the slots which has dampers inside, a choke geometry is introduced for this cavity. Through optimizations on this choke, the accelerating mode is fully reflected back into the cavity and all of harmful modes can be heavily suppressed. In addition, the nose shape and frequency tuner are also optimized in detail.