Beam test of an RF damped cavity at the Photon Factory storage ring

We have developed a new 500 MHz damped cavity [1~6], the feature of which is that the beam ducts with large diameter are attached to the cavity and that a part of the beam ducts is made of SiC. The higher-order-modes (HOMs), which propagate out from the cavity through the beam duct, are damped by the SiC parts. The low power measurement using a cold model and the high power test using a prototype model had been already done. In the autumn of 1996, two damped cavities were installed in the PF ring and operated in the scheduled user run for about two months. The operation of these new cavities was quite successful. On the last day of the scheduled user run before long shut down, we tried very high current beam and succeeded to store the current of 773 mA, the new record in the PF ring