Speaker
Description
The region of the chart of nuclei close to the doubly-magic nucleus 132Sn has been the object of
enormous interest in both experimental and theoretical investigations for the last several years. This
activity is well-motivated by the fact that nuclei with large neutron excess are an ideal playground
to verify the reliability of shell model predictions for nuclei far from stability. Crossing of the major
neutron (N=82) and proton (Z=50) shell closures allows for investigation of single-particle states
and interaction strengths in this neutron-rich region.
Our studies focus on the closest neighbours of 132Sn in order to investigate neutron single-particle
states: one-neutron particle 133Sn and two-neutron particle 134Sn. A better understanding of the
neutron-rich 132Sn region requires not only more data but also more precise.
In June 2016 fast timing and spectroscopy were employed together at the ISOLDE Decay Station
to study doubly magic 132Sn and its neighbours, including 132Sn,133Sn and 134Sn nuclei. Sn nuclei
were populated in ? decay of In isomers, produced from a UCx target unit equipped with a neutron
converter. Selective isomer ionisation provided by ISOLDE RILIS for odd-A 133In enabled to extend
knowledge about the structure of 133Sn, which is the main player to deduce single-particle states
in this region. In particular, the analysis of ? decay branch of 133In in conjuction with ?-n decay
branch of 134In can bring more information about the position of the ?p1=2 single-particle orbit,
for which a strong candidate was proposed [1], while the question about the position of ?i13=2 still
remains open for investigation.
Details of experimental setup and preliminary results will be presented. In comparison to
previous measurements exploring 132Sn region, the sensitivity was enhanced thanks to the use
of highly efficient clover-type Ge detectors and a new generation of fast timing detectors with
LaBr3(Ce) crystals.
[1] P. Hoff et al., Phys. Rev. Lett. 77, 1020 (1996).
