Generation of an intense metal-ion beam by a pulsed ion diode

Abstract

Intense pulsed metal-ion beams (∼100 keV, ∼1 kA, 0.5 μs, Pb and Cu) were generated by a pulsed magnetically insulated ion diode driven by a long-pulse Marx generator. The ion current density exceeded the Child–Langmuir value by a factor of 50. The ion beams were extracted from either an anode plasma produced by electron bombardment on a metal anode or by a vacuum-arc metal-plasma source. Metal-ion beams rich in high-energy multi-ionized ions and also impurity ions of H+, C+, and O+ were measured by a Thomson-parabola ion spectrometer and a magnetic mass analyzer. The amount of impurity ions were reduced by conditioning of the anode surface. A design was considered to develop an intense metal-ion source with a total ion current of 1 kA, an ion energy of 100–200 keV, a pulse width of 10 μs, and repetition rate of 10 Hz, all of which correspond to a 100 mA steady-state metal-ion beam.