Unsafe Coulomb excitation of {sup 240-244}Pu.

Conference · Thu Feb 04 04:00:00 EST 1999

OSTI ID:12402

Ahmad, I; Amro, H; Carpenter, M P; Chowdhury, P; Cizewski, J; Cline, D; Greene, J P; Hackman, G; Janssens, R V. F.; Khoo, T L; Lauritsen, T; Lister, C J; Macchiavelli, A O; Nisius, D T; Reiter, P; Seabury, E H; Seweryniak, D; Siem, S; Uusitalo, J; Wiedenhoever, I ; Wu, C Y

The high spin states of {sup 240}Pu and {sup 244}Pu have been investigated with GAMMASPHERE at ATLAS, using Coulomb excitation with a {sup 208}Pb beam at energies above the Coulomb barrier. Data on a transfer channel leading to {sup 242}Pu were obtained as well. In the case of {sup 244}Pu, the yrast band was extended to 34{h_bar} revealing the completed {pi}i{sub 13/2} alignment, a ''first'' for actinide nuclei. The yrast sequence of {sup 242}Pu was also extended to higher spin and a similar backbend was delineated. In contrast, while the ground state band of {sup 240}Pu was measured up to the highest rotational frequencies ever reported in the actinide region ({approximately}300 keV), no sign of particle alignment was observed. In this case, several observable such as the large B(E1)/B(E2) branching ratios in the negative parity band, and the vanishing energy staggering between the negative and positive parity bands suggest that the strength of octupole correlations increases with rotational frequency. These stronger correlations may well be responsible for delaying or suppressing the {pi}i{sub 13/2} particle alignment.

• Research Organization: Argonne National Lab., IL (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 12402
• Report Number(s): ANL/PHY/CP-98367
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ACTINIDE NUCLEI
BRANCHING RATIO
COULOMB EXCITATION
COULOMB FIELD
GAMMA SPECTROSCOPY
GROUND STATES
HIGH SPIN STATES
PARITY
PLUTONIUM 240
PLUTONIUM 242
PLUTONIUM 244
YRAST STATES