High Power Testing of Input Couplers for SuperKEKB

At KEKB, 32 ARES cavities have been successfully operated to store stably high-current electron and positron beams. Currently, 300 KW or more of RF power (freq. = 508.887 MHz) is fed to each ARES cavity through a coaxial-type input coupler. The design power capability of the input coupler is 400 kW at maximum for KEKB, and needs to be increased to 800 kW for SuperKEKB. Recently, we have constructed a new test stand to simulate the actual operating condition over 800 kW for the input coupler to drive the ARES cavity loaded with beam. This article reports the key features of the new test stand together with the recent results of high-power test.