title: Experiments with biased side electrodes in electron cyclotron resonance ion sources.
abstract: The output of highly charged ions from an electron cyclotron resonance ion source (ECRIS) consists of ionic losses from a highly confined plasma. Therefore, an increase of the output of the ions of interest always is a compromise between an increase in the confinement and an increase of the losses. One route towards a solution consists of attacking the losses in directions - i.e., radial directions - that do not contribute to the required output. This was demonstrated in an experiment (using the Kei ECRIS at NIRS, Japan) where radial losses were electrostatically reduced by positively biasing one set of six "side" electrodes surrounding the plasma in side-ward directions attached (insulated) to the cylindrical wall of the plasma chamber. Recently new studies were performed in two laboratories using two essentially different ion sources. At the BioNano ECRIS (Toyo University, Japan) various sets of electrodes were used; each of the electrodes could be biased individually. At the Atomki ECRIS (Hungary), one movable, off-axis side electrode was applied in technically two versions. The measurements show indeed a decrease of ionic losses but different effectivities as compared to the biased disk.
authors.affiliation: National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage-ku, Chiba-shi 263-8555, Japan.
authors.forename: A G
authors.initials: AG
authors.lastname: Drentje
authors.affiliation: National Institute of Radiological Sciences (NIRS), 4-9-1 Anagawa, Inage-ku, Chiba-shi 263-8555, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Kitagawa
authors.affiliation: Bio-Nano Electronics Research Centre, Toyo University, 2100 Kujirai, Kawagoe-shi 350-8585, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Uchida
authors.affiliation: Institute for Nuclear Research (Atomki), H-2026 Debrecen, Bem ter 18/c, Hungary.
authors.forename: R
authors.initials: R
authors.lastname: Rácz
authors.affiliation: Institute for Nuclear Research (Atomki), H-2026 Debrecen, Bem ter 18/c, Hungary.
authors.forename: S
authors.initials: S
authors.lastname: Biri
mesh_terms: D017357:Cyclotrons / Q000295:instrumentation*; D004566:Electrodes; D004583:Electrons