Extraction and focusing of an electron beam extracted from the duoplasmatron source

This work includes a study on electron beam extraction from the duoplasmatron source and its focusing by a magnetic lens. This study investigates the electron current below the magnetic lens under the influence of the discharge parameters, collector voltage and the focusing magnetic field. It is found that the influence of the filament power on increasing the electron current is obvious at V/sub c/ > 9 kv. The influence of the source magnetic field and pressure on the increase in electron current could be detected below the lens. The focusing magnetic field of the lens increases the electron current to a peak value at 600 gauss at pressure 6.5 X 10/sup -3/Torr and collector voltage 8 kv. It is found that the electron current below the lens (at zero magnetic field) is smaller than the current above it due to electron losses at low voltage. At collector potential > 9 kv and the use of the focusing magnetic field the electron losses could be lowered to zero value