Low Cost Expendable TWT Amplifier for ECM.

Preliminary design of the low cost TWT included a cost analysis, which indicated the division of approximately 50 for material and 50 for labor at the manufacturing cost level was appropriate to medium power TWTs. It was observed during this analysis that a significant percentage of the labor was devoted to alignment and testing of the tube. Thus, in addition to reducing the cost of material in assembly labor going in tube construction, consideration must be given to the realization of design which would minimize alignment and test time. Mechanical and electrical designs for the electron gun and focusing structure were considered in detail. Alternative designs were studied to determine which would yield the lowest cost, without compromising shelf life and performance. This study led to a stacked metal ceramic electron gun construction capable of withstanding the high bake-out temperature required to obtain the shelf life. The study of the metal-to-ceramic vacuum seal was confined to a beaded header utilizing Hybralox, a new inexpensive material capable of withstanding high temperatures. The PPM focusing structure constructed independent of the vacuum envelope was shown to be the lowest cost focusing method which could be realized with reasonable weight and efficiency. A detailed trade-off study on the methods of fabrication for the major cost items in the gun and focusing structure was considered.