Recent Results from Heavy Element Research at JYFL

Abstract

The gas-filled recoil separator RITU in conjunction with germanium detector arrays and the SACRED conversion electron array has been used for studies of nuclear structure in the region around ²⁵⁴No. Rotational spectra have been extracted using in-beam measurements with recoil gating or recoil decay tagging. Results from completed in-beam γ-ray studies of ^{252, 254}No as well as preliminary data from in-beam conversion electron measurements of ^{253, 254}No and γ-ray studies of ²⁵⁰Fm are presented. These measurements give strong support to the prediction that nuclei in this region of the nuclear chart are quadrupole-deformed in their ground state with β₂∼0.27. There are indications of an upbend occurring in the moment of inertia of ²⁵²No and ²⁵⁰ Fm at a frequency around 180 keV. Future prospects for these studies as well as for focal plane decay spectroscopy in the transfermium region using RITU are discussed.