Search for the two-octupole phonon vibrational state in {sup 208}Pb
- North Carolina State Univ., Raleigh, NC (United States)
The first excited state of {sup 208}Pb has J{sup pi} = 3{sup {minus}} and is interpreted as a one-phonon vibration of octupole character, leading to the expectation of a multiplet of 2-phonon octupole states at roughly twice the 3{sup {minus}} energy. Recently, experiments to search for members of this multiplet were performed by bombarding {sup 208}Pb targets with {sup 208}Pb beams at GSI and {sup 64}Ni and {sup 82}Se beams at HMI. A {gamma} ray at 2485 keV was observed in each experiment, but was attributed to 2-phonon excitations by the GSI group, whereas the HMI group assigned this {gamma} ray to {sup 207}Pb. The authors have performed an experiment at Argonne using 1305 MeV beams of {sup 208}Pb to bombard thick targets of {sup 208}Pb, {sup 209}Bi, {sup 58,64}Ni, and {sup 160}Gd. They have identified some 30 known {gamma} rays from {sup 208}Pb, and after unfolding these spectra for Compton response, they observe broad structures in the energy region expected for the decay of 2-phonon states. Furthermore, they have confirmed the placement of the 2485 keV line in {sup 207}Pb.
- OSTI ID:
- 199734
- Report Number(s):
- CONF-941129--
- Country of Publication:
- United States
- Language:
- English
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