and decimated using grids and apertures. Here, the DC discharge current or the RF discharge power are used to control the beam current.

The ion current density that can be accelerated using a gridded ion source is limited by the space charge effect, which is described by Child's law:

where is the voltage between the grids, is the distance between the grids, and is the ion mass.

The grids are spaced as closely as possible to increase the current