Mainz 2022 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 29: Structure and Dynamics of Nuclei V

HK 29.2: Talk

Tuesday, March 29, 2022, 16:15–16:30, HK-H6

Recent high-precision mass spectrometry of heavy and superheavy nuclides at SHIPTRAP — •Oliver Kaleja for the SHIPTRAP collaboration — University of Greifswald, Germany — GSI Darmstadt, Germany

Within the recent FAIR phase-0 program, the Penning-trap mass spectrometer SHIPTRAP at GSI in Darmstadt, Germany, was used to extend direct high-precision mass spectrometry to superheavy nuclides (Z≥ 104) in the vicinity of the N=152 shell closure. Besides lowest production rates down to few atoms per hour, an improved efficiency, ion sensitivity and mass-resolving power of up to 11 000 000 allowed resolving metastable states with half-lives >200 ms, i.e, ^251m,254mNo(Z=102), ^254m,255mLr(Z=103), ^257mRf(Z=104), and ^258mDb(Z=105) from their respective ground state. For the first time, isomer excitation energies in the range of ≈ 30 keV to 1.3 MeV were determined directly. In addition, multiple metastable states in a variety of heavy isotopes, many of which are close to the Z=82, N=126 shell closures, have been measured, e.g., for isotopes of Pb, Bi, Po, At, Rn, Fr (Z=82−87), Th(Z=90), and Cf(Z=98). This allowed the direct determination of the excitation energies of long-lived isomeric states and therefore to contribute to the understanding of the level and decay schemes of these heavy nuclei, complementing the findings from decay and laser spectroscopy investigations. In this contribution an overview of the experimental challenges and results is given.