Exploration of Collector Materials in High-Power Microwave Sources

Abstract

The plasma effects of energetic electron bombardment on component materials severely limit the output pulsed energies of high-power microwave (HPM) sources. This paper proposes a feasible method for choosing materials for beam collectors in HPM devices. First, electron energy deposition in metal materials is theoretically and numerically investigated. Considering the energy threshold resulting in material ablation, the resilience of several metals to intense relativistic electron beam (IREB) bombardment is compared. This resilience is mainly determined by the material density and melting point. Titanium shows good resilience compared with stainless steel, copper, molybdenum, and tungsten. With an incident 780 keV, 9.5-kA IREB, the maximum deposition energy in titanium just slightly exceeds its ablation threshold. Thus, the theoretical results indicate that titanium is a promising material for application in HPM devices. The experimental results validate the theoretical analyses. Compared with the conventional stainless steel collector, the titanium collector has better stability and lifetime. We intend to investigate more materials in future studies.