traveling-wave phototube

traveling-wave phototube

[′trav·əl·iŋ ¦wāv ′fōd·ə‚tüb]
(electronics)
A traveling-wave tube having a photocathode and an appropriate window to admit a modulated laser beam; the modulated laser beam causes emission of a current-modulated photoelectron beam, which in turn is accelerated by an electron gun and directed into the helical slow-wave structure of the tube.