This paper reviews the main types of r.f. power amplifiers which are, or may
be, used for particle accelerators. It covers solid-state devices, tetrodes,
inductive output tubes, klystrons, magnetrons, and gyrotrons with power outputs
greater than 10 kW c.w. or 100 kW pulsed at frequencies from 50 MHz to 30 GHz.
Factors affecting the satisfactory operation of amplifiers include cooling,
matching and protection circuits are discussed. The paper concludes with a
summary of the state of the art for the different technologies.Comment: 35 pages, contribution to the CAS - CERN Accelerator School:
Specialised Course on RF for Accelerators; 8 - 17 Jun 2010, Ebeltoft, Denmar
