Hollow cathodes and cold-start concepts
Ignition, restart, thermal balance, I-V behaviour and the difference between a cathode concept and the surrounding power / gas / test architecture.
Start is a system event
Ignition depends on cathode geometry, emitter state, gas flow and pressure, keeper configuration, power-supply behaviour and the surrounding vacuum system. A successful single start is not yet a qualified cold-start concept.
What I track
Start voltage and current, delay, gas transient, keeper behaviour, cathode voltage after transition, thermal state, restart repeatability and visible or electrical signs of erosion should be recorded together.
Qualification gap
The useful question is whether the complete cathode architecture can start repeatedly, reach the intended operating mode and preserve emitter and keeper condition over the required life envelope.