@techreport{oai:nifs-repository.repo.nii.ac.jp:00009508,
 author = {"Ando,  A. and Takeiri,  Y. and Kaneko,  O. and Oka,  Y. and Wada,  M. and Kuroda,  T."},
 month = {May},
 note = {"The production of the negative hydrogen ions in a large multicusp ion source has been investigated in a double-magnetic filter (DMF) configuration. In the DMF configuration, the energetic electrons are trapped by the mirror of a magnetic multicusp field, and only the thermal electrons are present in the center of the arc chamber. A large amount of H^- ions of more than 1 x 10^12 cm^-3 are produced in the center region. The electron current extracted with the H^- ions can be suppressed by a magnetic filter field in front of a plasma grid without affecting the H^- ion current. The experimental data obtained in the DMF configuration are compared with those obtained in a single-magnetic filter (SMF) configuration. In the SMF configuration, the energetic electrons are present in the center region, and the magnetic filter in front of a plasma grid reduces the electron density and temperature, which results in the reduction of the H^- ion current as well as the electron current. The extracted electron current and the optimum gas pressure for the H^- ion current are lower in the DMF configuration than those in the SMF configuration."},
 title = {Production of Negative Hydrogen Ions in a Large Multicusp Ion Source with Double-Magnetic Filter Configuration},
 year = {1992}
}