Analytical prediction and experimental verification of TWT and depressed collector performance using multidimensional computer programs

A comparison of experimental with computed results is presented for two high-performance octave-bandwidth TWT's, with multistage depressed collectors. The computations are carried out with advanced multidimensional computer programs which model the electron beam as a series of disks or rings of charge and follow their multidimensional trajectories from the RF input of the TWT, through the slow-wave structure, into the magnetic refocusing system, if any, to their points of impact in the depressed collector. TWT performance, collector efficiency, and collector current distribution are computed and the results compared with measurements reported previously. Power conservation and correct accounting of TWT and collector losses are observed. Very good agreement is obtained between the computed and measured collector efficiencies.