title: Effect of high energy electrons on H⁻ production and destruction in a high current DC negative ion source for cyclotron.
abstract: Recently, a filament driven multi-cusp negative ion source has been developed for proton cyclotrons in medical applications. In this study, numerical modeling of the filament arc-discharge source plasma has been done with kinetic modeling of electrons in the ion source plasmas by the multi-cusp arc-discharge code and zero dimensional rate equations for hydrogen molecules and negative ions. In this paper, main focus is placed on the effects of the arc-discharge power on the electron energy distribution function and the resultant H(-) production. The modelling results reasonably explains the dependence of the H(-) extraction current on the arc-discharge power in the experiments.
authors.affiliation: Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Onai
authors.affiliation: Sumitomo Heavy Industries, Ltd., Tokyo 141-6025, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Etoh
authors.affiliation: Sumitomo Heavy Industries, Ltd., Tokyo 141-6025, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Aoki
authors.affiliation: High Energy Accelerator Research Organization (KEK), Ibaraki, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Shibata
authors.affiliation: CERN Rte de Meyrin, 1200 Geneva, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Mattei
authors.affiliation: Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Fujita
authors.affiliation: Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Hatayama
authors.affiliation: CERN Rte de Meyrin, 1200 Geneva, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Lettry