Unidirectional Ion Generation and Geometric Focussing of Ions in a Reflex Triode

Experiments studying the phenomenology of the reflex triode ion accelerator have led to a simple anode design that produces an intense (5 kA average current, 1.7 MeV beam energy, 25 ns current pulse) pulsed ion beam in which greater than 95% of the ions generated are extracted through the virtual cathode. Subsequent experiments have also shown that a simple concentric-spherical anode-cathode geometry can be used to focus the ion beam and increase by an order of magnitude the on-axis ion flux to 1.1 kA/cm2.