Abstract
Electromagnetic modeling of the multicusp external antenna H− ion source for the Spallation
Neutron Source SNS has been performed in order to optimize high-power performance. During
development of the SNS external antenna ion source, antenna failures due to high voltage and
multicusp magnet holder rf heating concerns under stressful operating conditions led to rf
characteristics analysis. In rf simulations, the plasma was modeled as an equivalent lossy metal by
defining conductivity as . Insulation designs along with material selections such as ferrite and
Teflon could be included in the computer simulations to compare antenna gap potentials, surface
power dissipations, and input impedance at the operating frequencies, 2 and 13.56 MHz. Further
modeling and design improvements are outlined in the conclusion.
