title: H(-) ion source developments at the SNS.
abstract: The U.S. Spallation Neutron Source (SNS) will require substantially higher average and pulse H(-) beam currents than can be produced from conventional ion sources such as the base line SNS source. H(-) currents of 40-50 mA (SNS operations) and 70-100 mA (power upgrade project) with a rms emittance of 0.20-0.35pi mm mrad and a approximately 7% duty factor will be needed. We are therefore investigating several advanced ion source concepts based on rf plasma excitation. First, the performance characteristics of an external antenna source based on an Al(2)O(3) plasma chamber combined with an external multicusp magnetic configuration, an elemental Cs system, and plasma gun will be discussed. Second, the first plasma measurements of a helicon-driven H(-) ion source will also be presented.
authors.affiliation: Oak Ridge National Laboratory, Oak Ridge, TN 37830-6471, USA.
authors.forename: R F
authors.initials: RF
authors.lastname: Welton
authors.forename: M P
authors.initials: MP
authors.lastname: Stockli
authors.forename: S N
authors.initials: SN
authors.lastname: Murray
authors.forename: T R
authors.initials: TR
authors.lastname: Pennisi
authors.forename: B
authors.initials: B
authors.lastname: Han
authors.forename: Y
authors.initials: Y
authors.lastname: Kang
authors.forename: R H
authors.initials: RH
authors.lastname: Goulding
authors.forename: D W
authors.initials: DW
authors.lastname: Crisp
authors.forename: D O
authors.initials: DO
authors.lastname: Sparks
authors.forename: N P
authors.initials: NP
authors.lastname: Luciano
authors.forename: J R
authors.initials: JR
authors.lastname: Carmichael
authors.forename: J
authors.initials: J
authors.lastname: Carr