The T6 Hollow Cathode: Measurements and Modeling

Behavior of the xenon dispenser hollow cathode is known to be complex, exhibiting high through-anode ion emission, unusual particle energy distributions, and high plume erosion rates. A flight-type T6 hollow cathode was characterized using several diagnostic methods. Measurements involved a retarding potential analyzer, quadrupole mass spectrometer, and Langmuir probe. Far-field energy, flux, plasma potential, and charge state distribution data were obtained for plume ions at various operating points. The plume expansion was modeled by explicitly including both electrons and heavy particles in a combined Particle In Cell and direct simulation Monte Carlo approach. The simulations were in good agreement with measured ion energy distributions, which peaked at low energy in comparison to most other studies. Comparisons of ion emission and plasma potential profiles were relatively poor.