Traveling-wave-tube efficiency improvement by a low-cost technique for deposition of carbon on multistage depressed collector

摘要

A simple method of improving the traveling-wave-tube (TWT) and multistage depressed collector (MDC) efficiency has been demonstrated. The efficiency improvement was produced by the application of a thin layer of carbon to the copper electrodes of the MDC by means of a rapid, low-cost technique involving the pyrolysis of hydrocarbon oil in electric arc discharges. Experimental results with a representative TWT and MDC showed an 11 percent improvement in both the TWT and MDC efficiencies as compared to those of the same TWT and MDC efficiencies with bare copper electrode surfaces. An extended test with a 500-W, continuous wave (CW) TWT and small-sized MDC indicated good stability of the carbon coated electrode surfaces after a relatively small initial degradation in TWT overall and apparent MDC efficiencies.