3 GHz Barrel Open Cavity (BOC) RF pulse compressor for CTF3

Abstract

A prototype 3 GHz RF pulse compressor, based on a single 'Barrel shaped Open Cavity' (BOC), was designed, manufactured and successfully high power tested into a RF load. It is now planned to install five such devices in the CTF3 drive beam linac currently being built at CERN. A specific feature of the BOC is the so-called "whispering gallery" mode which has a high internal Q-factor. Contrary to other cavity-based pulse compressors, such as SLED or LIPS, with this mode one can operate in a resonant rotating wave regime. Consequently, when used as an RF pulse compressor a single BOC is sufficient, whereas the LIPS and SLED schemes require two cavities and a 3-dB hybrid. A short description of the BOC and the results of high power operation specific to the CTF3 drive beam linac are presented.