Beam extraction from a Hall-type ion accelerator

Fundamental characteristics of beam extraction from a Hall-type accelerator working with permanent magnets were investigated. Ions were extracted by an axial electric field E z in a small annular plasma channel with a radial magnetic field B r . Effects of discharge current and voltage, length of discharge channel, and gas flow rate were examined. It can deliver a large beam current density of more than 100 mA ∕ cm 2 with low beam energy of 50 eV . By biasing an additional plasma chamber attached at the extraction area, the beam energy was controlled independently of the beam current.