title: Power efficiency improvements with the radio frequency H⁻ ion source.
abstract: CW 13.56 MHz radio frequency-driven H(-) ion source is under development at the University of Jyväskylä for replacing an existing filament-driven ion source at the MCC30/15 cyclotron. Previously, production of 1 mA H(-) beam, which is the target intensity of the ion source, has been reported at 3 kW of RF power. The original ion source front plate with an adjustable electromagnet based filter field has been replaced with a new front plate with permanent magnet filter field. The new structure is more open and enables a higher flux of ro-vibrationally excited molecules towards the plasma electrode and provides a better control of the potential near the extraction due to a stronger separation of the main plasma from the plasma electrode. While the original system provided better control over the e(-)/H(-) ratio, the new configuration has led to a higher production efficiency of 1 mA H(-) at 1.75 kW RF power. The latest results and upgrade plans are presented.
authors.affiliation: Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Kalvas
authors.affiliation: Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä, Finland.
authors.forename: O
authors.initials: O
authors.lastname: Tarvainen
authors.affiliation: Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Komppula
authors.affiliation: Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä, Finland.
authors.forename: H
authors.initials: H
authors.lastname: Koivisto
authors.affiliation: Department of Physics, University of Jyväskylä, P.O. Box 35 (YFL), FI-40014 Jyväskylä, Finland.
authors.forename: J
authors.initials: J
authors.lastname: Tuunanen
authors.affiliation: D-Pace, Inc., P.O. Box 201, Nelson, British Columbia V1L 5P9, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Potkins
authors.affiliation: D-Pace, Inc., P.O. Box 201, Nelson, British Columbia V1L 5P9, Canada.
authors.forename: T
authors.initials: T
authors.lastname: Stewart
authors.affiliation: D-Pace, Inc., P.O. Box 201, Nelson, British Columbia V1L 5P9, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Dehnel