Abstract
This paper evaluates the performance of a bimodal carbon fiber cathode and a carbon-epoxy multicapillary cathode operating within a reflex-triode sealed-tube virtual cathode oscillator (vircator). The experimental results reveal that both cathodes exhibit similar emission behavior, although with some significant operational differences. An eight-stage 84-J pulse-forming network-based Marx generator serves to drive both cathodes at 250 kV and 3-4 kA with a ∼ 70 -ns pulsewidth. Both cathodes undergo conditioning over 10 000 pulses to determine gas evolution as well as electrical changes over time. Gas evolution of both cathodes is observed using a residual gas analyzer to determine individual gas constituents. A comparison of diode voltage, diode current, RF output, and outgassing data for both cathodes during vircator operation over 10 000 pulses is presented to quantify cathode performance in a sealed-tube vircator. Changes in cathode surface morphology, from virgin to postmortem, are discussed. Data for various anode-cathode gap distances, from 3 to 15 mm, are presented. The evolution of voltage and current inputs to the vircator is discussed.
Original language | English |
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Article number | 7163638 |
Pages (from-to) | 2670-2675 |
Number of pages | 6 |
Journal | IEEE Transactions on Plasma Science |
Volume | 43 |
Issue number | 8 |
DOIs | |
State | Published - Aug 1 2015 |
Keywords
- Cathodes
- electron emission
- electron tubes
- high power microwave generator.