Optimization of a dynamic velocity taper for a wide-band TWT design using Christine1D

A Dynamic Velocity Taper (DVT) has been optimized and applied to a wide bandwidth (3:1) helix TWT. The means of optimization with the Christine code are described, velocity profiles and the phase diagrams from analysis are examined, and measured results for both the tapered and untapered designs are presented. The recent addition of an optimization routine to the Christine 1D helix TWT simulation code makes available a tool to achieve an optimized design, by an automatic procedure using a modified steepest descent method to search for increased efficiency as TWT parameters are varied. The physics of the beam-circuit interaction are used by the optimizer to compute performance during each iteration of the optimization.