Pulsed ion beams extracted from vacuum arc ion source with double accelerator gap

We propose a new vacuum arc ion source with double diode structure. The well defined ion flux of the first (pre-acceleration) gap controls the dynamics of the second (main) gap. The main gap operates space charge or source limited mode depending on the current level of the injected ions. An insulator spark source is used to trigger a metal vapor vacuum arc discharge driven by a 20-element LC pulse forming network (PFN: 5Ω-100µs). The vacuum arc discharge typically produces plasma flux of 10²mA/cm² level at 10cm from the anode surface. An electrostatic grid is used to separate ions from plasma electrons. A high voltage LC-PFL of 10µs pulse length directly drive the second grid and the cathode to negative high potential. In the first gap, the voltage divided from the main voltage pulse accelerates ions to appropriate energy for stable formation of the ion emitting surface in the second (main) extraction gap.