Development of high-power ARES cavities

The ARES (Accelerator Resonantly coupled with Energy Storage) structure is a three-cavity system operated in the /spl pi//2 mode, where a HOM-damped accelerating cavity is coupled with an energy storage cavity via a coupling cavity equipped with a coaxial antenna damper to reduce the impedances of the parasitic 0 and /spl pi/ modes. Two high-power prototypes with different HOM-damping schemes have been developed, where one is with a quadrupole counter-mixing (QCM) choke structure and the other with grooved beam pipe one. Both prototypes have been tested with an electron beam of about 500 mA in the TRISTAN accumulation ring. This paper reports their RF structures together with some results of the high-power and high-current beam tests.