title: Improvements to the internal and external antenna H(-) ion sources at the Spallation Neutron Source.
abstract: The Spallation Neutron Source (SNS), a large scale neutron production facility, routinely operates with 30-40 mA peak current in the linac. Recent measurements have shown that our RF-driven internal antenna, Cs-enhanced, multi-cusp ion sources injects ∼55 mA of H(-) beam current (∼1 ms, 60 Hz) at 65-kV into a Radio Frequency Quadrupole (RFQ) accelerator through a closely coupled electrostatic Low-Energy Beam Transport system. Over the last several years a decrease in RFQ transmission and issues with internal antennas has stimulated source development at the SNS both for the internal and external antenna ion sources. This report discusses progress in improving internal antenna reliability, H(-) yield improvements which resulted from modifications to the outlet aperture assembly (applicable to both internal and external antenna sources) and studies made of the long standing problem of beam persistence with the external antenna source. The current status of the external antenna ion source will also be presented.
authors.affiliation: Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37830-6471, USA.
authors.forename: R F
authors.initials: RF
authors.lastname: Welton
authors.affiliation: Muons, Inc., 552 N. Batavia Avenue, Batavia, Illinois 60510, USA.
authors.forename: V G
authors.initials: VG
authors.lastname: Dudnikov
authors.affiliation: Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37830-6471, USA.
authors.forename: B X
authors.initials: BX
authors.lastname: Han
authors.affiliation: Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37830-6471, USA.
authors.forename: S N
authors.initials: SN
authors.lastname: Murray
authors.affiliation: Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37830-6471, USA.
authors.forename: T R
authors.initials: TR
authors.lastname: Pennisi
authors.affiliation: Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37830-6471, USA.
authors.forename: C
authors.initials: C
authors.lastname: Pillar
authors.affiliation: Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37830-6471, USA.
authors.forename: M
authors.initials: M
authors.lastname: Santana
authors.affiliation: Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37830-6471, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Stockli
authors.affiliation: Villanova University, 800E. Lancaster Ave, Villanova, Pennsylvania 19085, USA.
authors.forename: M W
authors.initials: MW
authors.lastname: Turvey