Speaker
Description
In nuclei near N∼90, low-lying level schemes often contain several unplaced transitions, and many excited states lack definitive spin and multipolarity assignments. This limits the extraction of electromagnetic matrix elements and hinders detailed interpretation of configuration mixing and nuclear structure. The structure of 158Er has been investigated following the β decay of 158Tm using the GRIFFIN spectrometer.
Internal conversion coefficients (ICCs) were determined from measured electron and γ-ray intensities and compared with theoretical values to establish transition multipolarities. Seventeen transitions have been assigned definitive multipolarities, and the spin-parity of twelve excited states were constrained or newly assigned. Six transitions exhibit enhanced ICC values relative to theoretical expectations, indicating multipole mixing with contributions consistent with E0 admixtures; these preliminary results will be presented.