Experimental Observation of Amplification by Interaction Between Two Electron Streams

The frequency range near 200 Mc was chosen for the first experimental test of the proposed method of amplification for reasons of convenience. The theory indicates that current density requirements increase with frequency, but that these requirements become severe only at the higher microwave frequencies. Availability of circuit parts and test equipment, rather than anticipated difficulties at higher frequencies, led to the choice that was made. The essential features of one of the double-stream amplifier tubes which has been constructed and operated are represented in Fig. 1. The output helix was identical with the input helix in construction and connection 1 A New Type of High Frequency Amplifier, J. R. Pierce and W. B. Hebenstreit, this issue of the B. S. T. J. 52 DOUBLE STREAM I 0 1 ba ^ tq ^ tq t M tq 0 1 C,,C2S,,S2T HJ^HQF| , P Z INNER AND OUTER CATHODES « ELECTRON STREAMS HELIX TERMINATION INPUT AND OUTPUT HELICES PROBES I 5 C o >-3 >5 Fig. 1--Representation of double-stream amplifier with helix output.