Bonn 2020 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 27: Structure and Dynamics of Nuclei VI

HK 27.2: Talk

Wednesday, April 1, 2020, 14:30–14:45, J-HS H

Mass measurements of neutron-deficient Yb isotopes around the N=82 shell closure, close to the proton dripline — •Beck Sönke for the TITAN collaboration — Justus-Liebig Universität, Giessen — GSI, Darmstadt

The nuclear mass reflects the binding energy of a nucleus and provides key information for nuclear structure, nuclear reactions and related fields like nuclear astrophysics. Mass measurements of exotic nuclei provide insight into the limits of nuclear existence and changes of the nuclear structure far from stability.

At TRIUMF’s Ion Trap for Atomic and Nuclear science (TITAN), masses of neutron-deficient lanthanides have been measured. The ions were produced by a proton beam impinging on a Ta target. The yield of Yb isotopes was enhanced by laser ionization. Mass measurements of the exotic nuclei were performed with TITAN’s Multiple-Reflection Time-of-Flight Mass Spectrometer (MR-TOF-MS). For the first time, the MR-TOF-MS was used as its own isobar separator by re-trapping the ions of interest and measuring their masses consecutively. This reduced isobaric background and more exotic nuclei could be measured.

Several masses were measured for the first time. This allows studying the evolution of the N=82 shell closure farthest away from stability. One measured mass is an anchor point of an α decay chain and as such determines the mass values of several heavier isotopes. Mass uncertainties of more than 10 isotopes are reduced by this measurement. The determination of their masses helps in pinning down the exact position of the drip line and finding possible p- and 2p-emitters.