Advanced injector systems for proton synchrotrons and accelerator-base
d boron neutron capture therapy systems are being developed at the Law
rence Berkeley National Laboratory. Multicusp ion sources, particularl
y those driven by radio frequency, have been tested for these applicat
ions. The use of a radio frequency induction discharge provides clean,
reliable, and long-life source operation. It has been demonstrated th
at the multicusp ion source can provide good-quality positive hydrogen
ion beams with a monatomic ion fraction higher than 90%. The extracta
ble ion current densities from this type of source can meet the inject
or requirements for both proton synchrotron and accelerator-based boro
n neutron capture therapy projects. (C) 1998 American Institute of Phy
sics.