Speaker
Description
Some highlights of nuclear structure research at Australia's Heavy Ion Accelerator Facility will be discussed. Mapping the emergence of nuclear collectivity is a focus, through $g$-factor and $B(E2)$ measurements. For example, such measurements on the Te isotopes allow us to map the pathway from the proton $g_{7/2}$ seniority structure in semimagic $^{134}$Te toward collective excitations near mid-shell as successive pairs of neutrons are removed. It is found that collectivity does not emerge suddenly, with the nucleus becoming collective as a whole, as might be inferred by examining energy patterns, such as $R_{4/2}$ energy ratios, alone. Rather, the 2$^+$ states become collective first whereas the first 4$^+$ and 6$^+$ states retain a significant seniority structure. This behaviour is not unique to the Te isotopes. The meaning of the term “pre-collective” nuclei will be discussed.
