Characteristic Observation of Intense Pulsed Aluminum Ion Beam in Magnetically Insulated Ion Diode With Vacuum Arc Ion Source

Intense pulsed heavy ion beam has been developed for a range of applications, including materials processing, particle accelerator injection for fundamental nuclear physics research, and other fundamental and applied purposes. For those applications, it is very important to generate high-purity ion beams with various ion species. We have developed a magnetically insulated ion diode for the generation of intense pulsed metallic ion beams in which the vacuum arc plasma gun is used as the metal ion source. The ion diode was operated at a diode voltage of about 200 kV, a diode current of about 15 kA, and a pulse duration of about 100 ns, and an ion beam with an ion current density of >200 A/cm² and a pulse duration of 40 ns was obtained at 50 mm downstream from the anode. By evaluating the ion species and the energy spectrum of the ion beam via a Thomson parabola spectrometer, it was confirmed that the ion beam consists of aluminum ions (Al⁺, Al²⁺, and Al³⁺) of energy 60-740 keV and proton impurities of energy 90-150 keV. The purity of the beam was estimated to be 89%, which is much higher than that of the pulsed ion beam produced in the conventional ion diode.