Effect of magnetic filter in a volume production multicusp ion source

D-Pace's volume production multicusp ion source utilizes dipole magnetic fields inside the plasma chamber to filter out energetic electrons that lead to the destruction of negative ions inside the source. The ion source uses the same magnetic field for the extraction of negative hydrogen and deuterium ions. The amount of deuterium ions extracted from the source is about 1/3 of the amount of negative hydrogen ions extracted. In this paper, we investigate if different magnetic field strengths are required for hydrogen and deuterium plasmas for maximum negative ion extraction. The effect of varying the strength of the magnetic filter fields in the extraction of negative ions of hydrogen and deuterium is studied. The response of plasma parameters like electron temperature and electron density to different magnetic fields are determined using a Langmuir probe.