New directions in RF sources

We examine the various high power RF sources on the ba-sis of the next linear collider requirements. The discussion is based on classification of the sources according to what we consider the most informative criteria. In the conven-tional acceleration scheme (e.g. SLAC) multiple sources generate the RF power. A variety of sources are consid-ered and they cover the spectrum from 9 to 19GHz. In the two beam accelerator scheme all the modules are driven by the same beam which has multi MeV (LBL/LLNL) up to a few GeV (CERN) electrons; the current carried by the beam is of order of kA. Two types of RF sources have been suggested: traveling wave (TW) structures and free electron laser (FEL). The operating frequency varies from device to device in the range of 9 to 35GHr. I