A. Gustafsson

Bio: A. Gustafsson is an academic researcher from CERN. The author has contributed to research in topics: Penning trap & Ion source. The author has an hindex of 2, co-authored 2 publications receiving 27 citations.

Mass-selective operation with REXTRAP

Abstract: At the radioactive ion-beam facility REX-ISOLDE more than 60 different types of radionuclide ions have been post-accelerated to energies up to 3.15 MeV/u within the last years. The transmission efficiency of the system has continually increased with gained operation experience. Apart from striving for the highest possible intensity, the beam purity is also of crucial importance for many experiments. For this reason isobaric contaminant suppression in the low energy stage of REX-ISOLDE has been investigated. Until now the Penning trap system REXTRAP was used solely as a device for bunching the incoming quasi-continuous radioactive ion-beam from ISOLDE and reducing the emittance for efficient injection into the REXEBIS charge breeder. The possibility of operating REXTRAP in a mass-resolving mode and injecting bunched beams from the recently installed radiofrequency quadrupole cooler and buncher ISCOOL has been studied in detail. Results related to transmission efficiency,achieved mass-resolving power, and limitations due to space-charge effects are presented.

In-trap decay of 61Mn and Coulomb excitation of 61Mn/61Fe

Abstract: At ISOL ( Isotope Separator On-Line) facilities, which utilize thick primary production targets, beams of neutron-rich iron isotopes are dificult to obtain due to the long extraction time of these isotopes out of the target matrix. At REX-ISOLDE, an exploratory experiment was carried out to investigate the possibility of producing a post-accelerated beam of neutron-rich iron isotopes by the in-trap decay of neutron-rich manganese isotopes, which are available at ISOLDE using the Resonance Ionization Laser Ion Source (RILIS). This production mechanism was tested for the first time at REX-ISOLDE with an intense and short-lived beam of Mn-61 isotopes. In this work, the proof of principle of this method is demonstrated, although the technical details of the trapping process are currently not well understood and are still under investigation. The first physics results on the Coulomb excitation of Mn-61 and Fe-61 are presented and compared to shell model calculations. (Less)

The Miniball spectrometer

Abstract: The Miniball germanium detector array has been operational at the REX (Radioactive ion beam EXperiment) post accelerator at the Isotope Separator On-Line facility ISOLDE at CERN since 2001. During the last decade, a series of successful Coulomb excitation and transfer reaction studies have been performed with this array, utilizing the unique and high-quality radioactive ion beams which are available at ISOLDE. In this article, an overview is given of the technical details of the full Miniball setup, including a description of the \(\gamma\)-ray and particle detectors, beam monitoring devices and methods to deal with beam contamination. The specific timing properties of the REX-ISOLDE facility are highlighted to indicate the sensitivity that can be achieved with the full Miniball setup. The article is finalized with a summary of some physics highlights at REX-ISOLDE and the utilization of the Miniball germanium detectors at other facilities.

On-line separation of short-lived nuclei by a multi-reflection time-of-flight device

Abstract: A multi-reflection time-of-flight (MR-ToF) mass analyzer has been integrated into ISOLTRAP, the precision mass spectrometer for on-line mass determinations of short-lived nuclides at ISOLDE/CERN. The new instrument improves ISOLTRAP by providing a fast separation of isobaric contaminant species as well as subsequent ion selection using the fast Bradbury–Nielsen gate. Suppression ratios of up to 104 and mass-resolving powers of over 105 have been reached in off-line experiments. Preliminary data from on-line applications illustrate the benefit and performance of the device and its potential in the context of the ISOLTRAP setup.

A high-performance multiple-reflection time-of-flight mass spectrometer and isobar separator for the research with exotic nuclei

Abstract: A novel multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) and isobar separator for the research with exotic nuclides at low-energy rare isotope beam facilities has been developed, commissioned and characterized. It can be used (i) as broadband mass spectrometer with medium resolution, (ii) as highly accurate mass spectrometer for direct mass measurements and (iii) as high-resolution mass separator. The device features a worldwide unique combination of performance characteristics: a mass resolving power of 600,000 (FWHM), a mass measurement accuracy of ~ 10 − 7 , large ion capacities in excess of 106 ions per second, a transmission efficiency of up to 70%, single-ion sensitivity, and cycle frequencies of up to 400 Hz have been achieved. The spatial separation of close-lying isobars with an intensity ratio of 200:1 and a binding energy difference as small as 4 MeV has been demonstrated. The MR-TOF-MS is ideally suited for experiments with rare and very short-lived nuclei at present and future in-flight, ISOL or IGISOL facilities, such as the FRS Ion-Catcher and SHIP/SHIPTRAP at GSI, TITAN at TRIUMF, IGISOL at the University of Jyvaskyla and the Low-Energy Branch of the Super-FRS at FAIR.