High Power Klystrons

This paper will review the evolution of high power klystrons and their applications in supplying rf energy for linear accelerators. Other types of possible rf sources were considered for SLAC, and the reasons for the selection of klystrons will be given. A brief review of klystron types in use for various accelerators will also be given, but the emphasis will be on the work done by Stanford and its subcontractors in developing klystrons capable of achieving peak powers in excess of 20 MW and average powers of 20 kW for use with the two-mile Stanford linear accelerator.