Twystron

a multicavity amplifier klystron in which the output section is replaced with a system of coupled resonators. In a Twystron, the electrons emitted by the cathode first pass through the klystron resonators, where they are grouped into bunches, as in a conventional klystron; they then pass through the system of coupled resonators, where they excite a traveling wave. Upon interaction with this wave, part of the kinetic energy of the electrons is converted into microwave energy, as in a conventional traveling-wave tube. The use of coupled resonators increases the operational frequency bandwidth to 7–15 percent of the mean frequency.

Twystrons provide the broadest bandwidths of all high-pulse-power microwave devices. They are manufactured for operation in the superhigh-frequency (microwave) band (wavelengths from 5 to 10 cm) and have pulse power ratings of 3–8 megawatts, gains of 35–50 decibels, and efficiencies of 35–40 percent. Twystrons were developed in the USA in the 1960’s by Varian Associates. They are used chiefly as transmitters in high-power radar installations on land and on board ships.