0000000000276833
AUTHOR
Christine Böhm
Mass spectrometry and decay spectroscopy of isomers across the Z=82 shell closure
Recent results from a measurement campaign studying the isomerism in neutron-deficient Tl isotopes are presented. The measurements make use of a nuclear spectroscopy setup coupled to the high-resolution Penning-trap mass spectrometer ISOLTRAP at CERN's radioactive ion-beam facility ISOLDE. The mass values of 190,194Tl are improved and a mass-spin-state assignment is carried out. An additional mass measurement of the grandparent nuclide 198At allows the deduction of the spin-state ordering in 190Tl. As a result, the excitation energies of the isomers in both Tl isotopes are determined for the first time to Eex(194Tl)=260(15) keV and E ex(190Tl)=89(12) keV. Furthermore, this allows anchoring …
Recent Exploits of the ISOLTRAP Mass Spectrometer
Abstract The Penning-trap mass spectrometer ISOLTRAP, located at the isotope-separator facility ISOLDE (CERN), is presented in its current form taking into account technical developments since 2007. Three areas of developments are presented. The reference ion sources have been modified to guarantee a sufficient supply of reference ions for mass measurements and systematic studies. Different excitation schemes have been investigated for manipulation of the ion motion in the Penning trap, to enhance either the purification or measurement process. A multi-reflection time-of-flight mass separator has been implemented and can now be routinely used for purification and as a versatile tool for bea…
Surveying the N=40 island of inversion with new manganese masses
High-precision mass measurements of neutron-rich 57−66Mn and 61−63Fe isotopes are reported. The new mass surface shows no shell closure at N=40. In contrast, there is an increase of the two-neutron separation energy at N=38. This behavior is consistent with the onset of collectivity due to the occupation of intruder states from higher orbits, in analogy with the well known “island of inversion” around N=20. Our results indicate that the neutron-rich Mn isotopes, starting from 63Mn, are most likely within the new island of inversion. From the new mass surface, we evaluate the empirical proton-neutron interaction and the pairing gap, both playing a significant role in the structural changes i…
High-precision Penning-trap mass measurements of heavy xenon isotopes for nuclear structure studies
With the double Penning-trap mass spectrometer ISOLTRAP at ISOLDE/CERN the masses of the neutron-rich isotopes $^{136\ensuremath{-}146}\mathrm{Xe}$ were measured with a relative uncertainty of the order of ${10}^{\ensuremath{-}8}$ to ${10}^{\ensuremath{-}7}$. In particular, the masses of $^{144\ensuremath{-}146}\mathrm{Xe}$ were measured for the first time. These new mass values allow one to extend calculations of the mass surface in this region. Proton-Neutron interaction strength, obtained from double differences of binding energies, relate to subtle structural effects, such as the onset of octupole correlations, the growth of collectivity, and its relation to the underlying shell model l…