Shapes studies in neutron-rich cerium isotopes

Student: Magda Satrazani
Supervisor: Liam Gaffney

Belonging to the region of heavy nuclei of the nuclide chart, 146Ce is characterized by a large number of protons and neutrons outside of the so-called closed shells, causing it to have a deformed shape. My project aims to measure key observables related to the charge distribution of this nucleus, since previous studies indicate that it does not follow a spherical form but instead, a pear–shaped one. This octupole mode of deformation manifests with the appearance of an excited 3- state, which I will investigate using beta-decay spectroscopy.

A beam of 146Cs was produced at the ISAC facility at TRIUMF and studied using the special configuration of the GRIFFIN spectrometer. In this experiment, we were able to detect and measure with high precision and efficiency the characteristic energies of the γ–rays and β–particles that are emitted in the decay and subsequent de-excitation of the daughter nuclei. The measured energies will give us information on the initial and final states of the nucleus, helping to determine the degree to which octupole deformation is important. Also, by measuring and studying specific parameters, such as the lifetime of the excited states, we will manage to gain more knowledge on the magnitude of this deformation. Further to this we hope to also investigate the nature of vibrational and/or rotational states, specifically the origin of the first 0+ excited state.