Microwave modes in the FXR accelerator cavity

Swept-frequency, microwave transmission measurements have been carried out on a production-model, ferrite loaded FXR cavity, both with and without further loading by termination of the four ballast load and feedline ports. Modes closely corresponding to the TM/sub 010/ and TM/sub 110/ modes of a simple pillbox cavity have been identified at 162 MHz and 261 MHz, respectively. The Q values of these modes are inherently low (Q/sub 0/ = 16 and 50, respectively) because of the ferrite loading. Under fully terminated conditions, the Q values are too low to be measurable, that is, the modes are either totally suppressed or very heavily damped.