Frankfurt 2014 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 32: Struktur und Dynamik von Kernen
HK 32.2: Vortrag
Mittwoch, 19. März 2014, 17:00–17:15, HZ 5
Probing the shell closure at N=32 by mass measurements of neutron-rich potassium isotopes — •M. Rosenbusch for the ISOLTRAP collaboration — Ernst-Moritz-Arndt-Universität Greifswald
The Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN has been set up for precision mass measurements of short-lived nuclides and has been continuously improved for accessing more exotic nuclides. A crucial step forward has been made with the installation of a multi-reflection time-of-flight mass separator (MR-ToF MS), which enables high-resolution mass separation of contaminated ions, resulting, e.g., in the measurement of 82Zn [1]. More recently, mass measurements have been performed directly in the MR-ToF MS instead of using a Penning trap. This paved the way for the mass determination of 53,54Ca [2], which would not have succeeded in ISOLTRAP’s Penning traps. The obtained two-neutron separation energies (S2n) unambiguously confirm a shell closure at N=32, indicated earlier by measurements of the excitation energies of the first 2+ state in 52Ca [3]. In addition, with the MR-ToF MS at ISOLTRAP the masses of 52K and 53K have been determined for the first time. With a half-life of only 30 ms, 53K is the shortest-lived nuclide ever investigated at ISOLTRAP. The data are currently under evaluation. In this contribution, the new S2n values will be presented and the crossing of the neutron shell closure at N=32 for potassium will be discussed. [1] R. N. Wolf et al., Phys. Rev. Lett. 110, 041101 (2013);[2] F. Wienholtz et al., Nature 498, 346-349 (2013);[3] A. Huck et al., Phys. Rev. C 31, 2226 (1985)