title: Development of a Kingdon ion trap system for trapping externally injected highly charged ions.
abstract: We have developed a Kingdon ion trap system for the purpose of the laboratory observation of the x-ray forbidden transitions of highly charged ions (HCIs). Externally injected Ar(q+) (q = 5-7) with kinetic energies of 6q keV were successfully trapped in the ion trap. The energy distribution of trapped ions is discussed in detail on the basis of numerical simulations. The combination of the Kingdon ion trap and the time-of-flight mass spectrometer enabled us to measure precise trapping lifetimes of HCIs. As a performance test of the instrument, we measured trapping lifetimes of Ar(q+) (q = 5-7) under a constant number density of H2 and determined the charge-transfer cross sections of Ar(q+)(q = 5, 6)-H2 collision systems at binary collision energies of a few eV. It was confirmed that the present cross section data are consistent with previous data and the values estimated by some scaling formula.
authors.affiliation: Department of Physics, Sophia University, 7-1 Kioicho, Chiyoda, Tokyo 102-8554, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Numadate
authors.affiliation: Department of Physics, Sophia University, 7-1 Kioicho, Chiyoda, Tokyo 102-8554, Japan.
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Okada
authors.affiliation: Institute for Laser Science, University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-0021, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Nakamura
authors.affiliation: Department of Physics, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Tanuma