New high spin states and band termination in {sup 83}Y and {sup 84}Zr

Journal Article · Sat Mar 01 04:00:00 EST 1997 · Physical Review, C

DOI:https://doi.org/10.1103/PhysRevC.55.1108· OSTI ID:512751

Johnson, T D; Aprahamian, A ^[1]; Lister, C J; Blumenthal, D J; Crowell, B ^[2]; Chowdhury, P ^[3]; Fallon, P; Machiavelli, A O ^[4]

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1. University of Notre Dame, Notre Dame, Indiana 46556 (United States)
2. Argonne National Laboratory, Argonne, Illinois 60439 (United States)
3. University of Massachusetts, Lowell, Massachusetts 01854 (United States)
4. Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

The gamma decay of high spin yrast states in {sup 83}Y up to I{sup {pi}}=59/2{sup +} and 53/2{sup {minus}} have been observed using the reaction {sup 58}Ni({sup 29}Si,3p) at 110 MeV and the Gammasphere Early Implementation Array. The level scheme has been substantially extended due to the observations of several new transitions in all of the bands. A sequence of transitions feeding into the positive parity yrast band above I{sup {pi}}=47/2{sup +} seems to be consistent with a noncollective oblate structure expected at these high spins. A similar cascade is found in the data for {sup 84}Zr. A new forking of the favored negative parity band is found which may be due to neutron alignment polarizing the core to a different shape. This suggests that the {open_quotes}isomeric{close_quote}{close_quote} band in {sup 83}Y, for which one more connecting transition was found, is of a similar nature to other high-K bands found in this region. Lifetime measurements in the unfavored negative parity band are consistent with cranking calculations which predict a nearly oblate shape with a deformation parameter {beta}{sub 2}{approx}0.2. A qualitative analysis of line shapes at very high spins suggests the persistence of collectivity in the yrast sequence to the highest excitations seen. {copyright} {ital 1997} {ital The American Physical Society}

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 512751
• Journal Information: Physical Review, C, Journal Name: Physical Review, C Journal Issue: 3 Vol. 55; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ALIGNMENT
DEFORMATION
EXCITATION
GAMMA DECAY
HIGH SPIN STATES
ISOMERIC NUCLEI
LIFETIME
MEV RANGE 100-1000
NICKEL 58 TARGET
PARITY
SHAPE
SILICON 29 REACTIONS
YRAST STATES
YTTRIUM 83
ZIRCONIUM 84