Seminarium: Spectroscopy of transfermium nuclei as a stepping stone towards the superheavy island of stability

  • Datum:
  • Plats: Ångströmlaboratoriet Å80101
  • Föreläsare: Dr. Mikael Sandzelius Department of Physics, University of Jyväskylä, Finland
  • Kontaktperson: Andreas Solders
  • Seminarium

In the Very Heavy Element (VHE) and Super Heavy Element (SHE) region there exist a rather clear disagreement between the prediction of the positioning of the next spherical shell gap. Different models predict either Z=124 or Z=120 as the next possible spherical shell closure above Z=82. However, spectroscopic information for these nuclei is as of today non-existent, and probably will remain so for the foreseeable future due to minuscule production cross-sections. In the VHE transfermium region, for 100<Z<106 and N≈152, nuclei can readily be produced in sufficient quantity to extract spectroscopic information (with in-beam and delayed decay spectroscopy). Moreover, these nuclei are relatively strongly deformed in their ground state. This deformation causes intruder states emanating from the SHE region (above Z=124) to come down in energy forming orbitals at the Fermi surface in some transfermium nuclei. Therefore it is of vital importance to map the single-particle states near the Fermi surface in order to test the success and validity of nuclear models.

In particular, odd-mass nuclei provide the opportunity to test single-particle spectra predicted by theory. Thus, the study of transfermium nuclei around the deformed region of N=152 and Z>100 can be viewed as a stepping stone towards superheavy nuclei and the nebulous island of stability. In the transfermium region there exists the possibility to probe the orbitals that are relevant in these very exotic nuclei with significantly higher N and Z numbers, which are otherwise inaccessible with today′s technology.

This seminar will give an overview of some of the spectroscopic information recently gathered in the 100<Z<106 region around the deformed region of N=152, and also present some future experiments planned at JYFL. Also, some experimental challenges and limitations to what we can measure will be presented.