title: Producing persistent, high-current, high-duty-factor H- beams for routine 1 MW operation of Spallation Neutron Source (invited).
abstract: Since 2009, the Spallation Neutron Source (SNS) has been producing neutrons with ion beam powers near 1 MW, which requires the extraction of ∼50 mA H(-) ions from the ion source with a ∼5% duty factor. The 50 mA are achieved after an initial dose of ∼3 mg of Cs and heating the Cs collar to ∼170 °C. The 50 mA normally persist for the entire 4-week source service cycles. Fundamental processes are reviewed to elucidate the persistence of the SNS H(-) beams without a steady feed of Cs and why the Cs collar temperature may have to be kept near 170 °C.
authors.affiliation: Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA. stockli@sns.gov
authors.forename: Martin P
authors.initials: MP
authors.lastname: Stockli
authors.forename: B X
authors.initials: BX
authors.lastname: Han
authors.forename: T W
authors.initials: TW
authors.lastname: Hardek
authors.forename: Y W
authors.initials: YW
authors.lastname: Kang
authors.forename: S N
authors.initials: SN
authors.lastname: Murray
authors.forename: T R
authors.initials: TR
authors.lastname: Pennisi
authors.forename: C
authors.initials: C
authors.lastname: Piller
authors.forename: M
authors.initials: M
authors.lastname: Santana
authors.forename: R
authors.initials: R
authors.lastname: Welton