Recent results from HERA: Spectroscopy of neutron-deficient Po nuclei
- Rutgers Univ., New Brunswick, NJ (United States)
To study the onset of collective motion in nuclei far from stability the authors have begun an extensive program to study the neutron-deficient polonium nuclei with the HERA array of 20 Compton-Suppressed Germanium detectors, which was developed by Drs. Diamond and Stephens at LBL. With Si reactions on Yb targets the authors have studied {sup 200, 198, 196}Po, as well as {sup 199,201}Po. Because of the increased competition between fusion and fission, these measurements are near the limit of conventional in-beam spectroscopy. The low-lying structure of the heavier isotopes shows little evidence for collectivity. However, in {sup 196}Po the energy of the 2{sub 1}{sup +} state has come down dramatically, and the levels up to the 8{sup +} show a relatively even energy spacing, consistent with the onset of vibrational motion. In addition, low-lying 2{sub 2}{sup +} and 4{sub 2}{sup +} states have been identified in both {sup 196, 198}Po, which could indicate 4p-2h, more collective excitations across the Z=82 shell gap. The structure of the odd-A nuclei further probes that of the even cores. In addition, the Pb isotopes show considerable evidence for superdeformed rotational bands and excitations built upon oblate two-proton 11{sup {minus}} states. The present talk will summarize the systematical behavior of the Po isotopes and discuss the role of collective excitations.
- OSTI ID:
- 141173
- Report Number(s):
- CONF-930304--
- Country of Publication:
- United States
- Language:
- English
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