State of the art of Klystrons .1.

After a short description of the basic principle of a Klystron presently interesting models are considered. Especially the state of the art of multi-cavity amplifier Klystrons with internal and external resonators is discussed. With Klystrons in the classic design the CW-power could be extended to the lower MW-region. Ar increased beam voltages pulsepowers of some 100 MW are attained. The CW-tubes are used above all in the final stages of TV-transmitters, the pulse tubes to feed the cavities of particle accelerators, In the last years the requirements with regard to power and frequency of the pulse power tubes have steadily increased. A novel design using another mechanism for the density modulation of a high-current, relativistic hollow beam is under investigation since 10 years. An enhancement oi the pulse power up to the GW-region is expected. From other variants of the Klystron the practically used inductive output tube (Klystrode) and the multiple-beam Klystron are discussed along with three further designs based on the Klystron principle which are in the grate of development.