Technique to increase the H+ ion fraction in a multicusp source

It is possible to filter out the primary ionizing electrons from the ion extraction region of a multicusp source by installing the filament inside the dipole fields of the permanent magnets and thereby enhance the H+ ion species in the extracted beam. An optimum position of the filament has been determined such that a quiescent plasma together with a uniform plasma density profile across the extraction plane can be obtained.