Two Monte Carlo simulation codes: (a) neutral transport code and (b) negative ion (H-) transport code, have been developed to understand transport phenomena in negative ion sources. In the neutral transport code, Boltzmann equations for hydrogen molecules (H2) and atoms (H) are solved. Three dimensional (3D) spatial distributions of H2, H, and H- production are obtained for a tandem negative ion source. The volume production of H- is limited to the area around the gas inlet in the first chamber and near the plasma grid in the second chamber. On the other hand, distribution of H- surface production is shown to be almost uniform over all the plasma grid surface. In the negative ion code, H- trajectories are calculated by numerically solving the 3D equation of motion for H- ions. The effects of the magnetic filter on the extraction probability of surface produced H- ions are mainly studied. The dependence of the extraction probability on the field strength is small.
|Number of pages||4|
|Journal||Review of Scientific Instruments|
|Issue number||2 II|
|Publication status||Published - 2000 Feb|
|Event||The 8th International Conference on Ion Sources (ICIS '99) - Kyoto, Japan|
Duration: 1999 Sept 6 → 1999 Sept 10
ASJC Scopus subject areas