Rapid crystallization of externally produced ions in a Penning trap

We have studied the cooling dynamics, formation process, and geometric structure of mesoscopic crystals of externally produced magnesium ions in a Penning trap. We present a cooling model and measurements for a combination of buffer gas cooling and laser cooling which has been found to reduce the ion kinetic energy by eight orders of magnitude from several hundreds of eV to μeV and below within seconds. With ion numbers of the order of 1 × 103 to 1 × 105, such cooling leads to the formation of ion Coulomb crystals which display a characteristic shell structure in agreement with the theory of non-neutral plasmas. We show the production and characterization of two-species ion crystals as a means of sympathetic cooling of ions lacking a suitable laser-cooling transition

Penning-trap experiments for spectroscopy of highly-charged ions at HITRAP.

Highly charged ions offer the possibility to measure electronic fine structures and hyperfine structures with precisions of optical lasers. Microwave spectroscopy of transitions between Zeeman substates further yields magnetic moments (g-factors) of bound electrons, making tests of calculations in the framework of bound-state QED possible in the strong-field regime. We present the SPECTRAP and ARTEMIS experiments, which are currently being commissioned with highly charged ions in the framework of the HITRAP facility at GSI, Germany. We present the scientific outline, the experimental setups and first results with confined ions

Laser spectroscopy of the ground-state hyperfine structure in H-like and Li-like bismuth

The LIBELLE experiment performed at the experimental storage ring (ESR) at the GSI Helmholtz Center in Darmstadt aims for the determination of the ground state hyperfine (HFS) transitions and lifetimes in hydrogen-like (²⁰⁹Bi⁸²⁺) and lithium-like (²⁰⁹Bi⁸⁰⁺) bismuth. The study of HFS transitions in highly charged ions enables precision tests of QED in extreme electric and magnetic fields otherwise not attainable in laboratory experiments. While the HFS transition in H-like bismuth was already observed in earlier experiments at the ESR, the LIBELLE experiment succeeded for the first time to measure the HFS transition in Li-like bismuth in a laser spectroscopy experiment

Laser spectroscopy of the ground-state hyperfine structure in H-like and Li-like bismuth

The LIBELLE experiment performed at the experimental storage ring (ESR) at the GSI Helmholtz Center in Darmstadt aims for the determination of the ground state hyperfine (HFS) transitions and lifetimes in hydrogen-like (209Bi82+) and lithium-like (209Bi80+) bismuth. The study of HFS transitions in highly charged ions enables precision tests of QED in extreme electric and magnetic fields otherwise not attainable in laboratory experiments. While the HFS transition in H-like bismuth was already observed in earlier experiments at the ESR, the LIBELLE experiment succeeded for the first time to measure the HFS transition in Li-like bismuth in a laser spectroscopy experiment

Lifetimes and g-factors of the HFS states in H-like and Li-like bismuth

Journal of Physics B: Atomic, Molecular and Optical Physics Paper • The following article is OPEN ACCESS Lifetimes and g-factors of the HFS states in H-like and Li-like bismuth Volker Hannen1 , Jonas Vollbrecht1, Zoran Andelkovic2, Carsten Brandau2,3, Andreas Dax4, Wolfgang Geithner2, Christopher Geppert5,6, Christian Gorges5,6, Michael Hammen6,7, Simon Kaufmann5Show full author list Published 2 April 2019 • © 2019 IOP Publishing Ltd Journal of Physics B: Atomic, Molecular and Optical Physics, Volume 52, Number 8 Download Article PDF Figures References 264 Total downloads Article has an altmetric score of 1 Turn on MathJax Share this article Share this content via email Share on Facebook Share on Twitter Share on Google+ Share on CiteULike Share on Mendeley Article information Abstract The LIBELLE experiment performed at the experimental storage ring at the GSI Helmholtz Center for Heavy Ion Research in Darmstadt, Germany, has successfully determined the ground state hyperfine (HFS) splittings in hydrogen-like (${}^{209}{\mathrm{Bi}}^{82+}$) and lithium-like (${}^{209}{\mathrm{Bi}}^{80+}$) bismuth. The study of HFS transitions in highly charged ions enables precision tests of QED in extreme electric and magnetic fields otherwise not attainable in laboratory experiments. Besides the transition wavelengths the time-resolved detection of fluorescence photons following the excitation of the ions by a pulsed laser system also allows the extraction of lifetimes of the upper HFS levels and g-factors of the bound 1s and 2s electrons for both charge states. While the lifetime of the upper HFS state in ${}^{209}{\mathrm{Bi}}^{82+}$ has already been measured in earlier experiments, an experimental value for lifetime of this state in ${}^{209}{\mathrm{Bi}}^{80+}$ is reported for the first time in this work

COMPASS-A COMPAct decay spectroscopy set-up

© 2018 Elsevier B.V. A compact silicon detector array with high spatial granularity and fast, fully digital data recording has been developed and commissioned for the investigation of heavy and superheavy nuclear species. The detector array can be combined in close geometry with large volume germanium detectors. It offers comprehensive particle and photon coincidence and correlation spectroscopy by highly efficient evaporation residue, α γ conversion electron and X-ray detection supported by the high granularity of the implantation chip. Access to fast decay events in the sub-microsecond region is made possible by the fast timing properties of the digital signal processing. A novel Si-chip support design allows direct cooling of the Si-chips and short signal transport. The compact and modular mechanical design equipped with a standard flange facilitates its transport and connection to different separators at different ion beam facilities. After initial tests, first α-γ coincidence spectroscopy experiments have been performed at the LISE separator of GANIL in Caen, France, in FULIS (velocity filter) mode and at the velocity filter SHIP of GSI in Darmstadt, Germany.status: publishe