Study Of H- Production In Dc H- Source Of Medical Cyclotron

A filament driven multi-cusp negative hydrogen ion source has been developed for proton cyclotrons. In order to increase the H- beam current, the dependences of H- beam current on various design/operating parameters has been studied experimentally and numerically. In this paper, the effects of are-discharge voltage and current on H- production via the volume production process are investigated by three-dimensional kinetic modeling of electrons in the source plasma and zero-dimensional rate equations. This numerical analysis reproduces the experimental results of H- beam current dependence on the are-discharge condition, and also gives reasonable explanations for their characteristics. (C) 2016 The Japan Society of Plasma Science and Nuclear Fusion Research