  A new ion source will be prepared for the CYCLONE30 commercial cyclotron with
a much advanced performance compared with the previous one. The newly designed
ion source has a very large transparency without deteriorating the beam optics,
which is designed to deliver an H- beam at 30 keV. The plasma generator of the
ion source is of an axially cusped bucket type, and the whole inner wall,
except the cathode filaments and plasma electrode side, functions as an anode.
The accelerator assembly consists of three circular aperture electrodes made of
copper. The simulation study was focused on finding parameter sets that raise
the percent of beam transmitted as large as possible and reduces the beam
divergence as low as possible. From the simulation results, it was concluded
that it is possible to achieve this goal by sliming the plasma electrode (G1),
shortening the first gap (G1-G2), and adjusting the G2 voltage.
