title: Storing keV negative ions for an hour: the lifetime of the metastable ^(2)P((1/2)^(o)) level in ^(32)S^(-).
abstract: We use a novel electrostatic ion storage ring to measure the radiative lifetime of the upper level in the 3p^{5} ^{2}P_{1/2}^{o}→3p^{5} ^{2}P_{3/2}^{o} spontaneous radiative decay in ^{32}S^{-} to be 503±54  sec. This is by orders of magnitude the longest lifetime ever measured in a negatively charged ion. Cryogenic cooling of the storage ring gives a residual-gas pressure of a few times 10^{-14} mbar at 13 K and storage of 10 keV sulfur anions for more than an hour. Our experimental results differ by 1.3σ from the only available theoretical prediction [P. Andersson et al., Phys. Rev. A 73, 032705 (2006)].
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Bäckström
authors.affiliation: Department of Physics, University of Gothenburg, SE-412 96 Göteborg, Sweden.
authors.forename: D
authors.initials: D
authors.lastname: Hanstorp
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: O M
authors.initials: OM
authors.lastname: Hole
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.|Institute of Physics, Jan Kochanowski University, 25-369 Kielce, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Kaminska
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: R F
authors.initials: RF
authors.lastname: Nascimento
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Blom
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Björkhage
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Källberg
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Löfgren
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Reinhed
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Rosén
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Simonsson
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: R D
authors.initials: RD
authors.lastname: Thomas
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Mannervik
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: H T
authors.initials: HT
authors.lastname: Schmidt
authors.affiliation: Department of Physics, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Cederquist