Measurements on prototype cavities (352 MHz) for the Advanced Photon Source (APS)

HOM damping with coaxial dampers in a pillbox cavity without the fundamental mode frequency rejection filter

“…Measurement of the damping ratio of thirteen HOMs is shown in Table 1. These modes are the cylindrical equivalent of the higher-order TM modes of the storage ring single cell cavity to be used in the APS and can cause beam instability [8,9]. Measurements are taken in dB scale which is related as 10 log lS21I2.…”