New isomers and medium-spin structure of the {sup 95}Y nucleus

Journal Article · Wed Apr 15 04:00:00 EDT 2009 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.79.044304· OSTI ID:21289864

Urban, W ^[1]; Sieja, K ^[2]; Simpson, G S ^[1]; Faust, H ^[1]; Rzaca-Urban, T; Zlomaniec, A; Lukasiewicz, M ^[3]; Smith, A G; Durell, J L; Smith, J F; Varley, B J ^[4]; Nowacki, F ^[5]; Ahmad, I ^[6]

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1. Institut Laue-Langevin, 6 rue J. Horowitz, F-38042 Grenoble (France)
2. Gesellschaft fuer Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt, Germany and Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)
3. Faculty of Physics, University of Warsaw, ul. Hoza 69, PL-00-681 Warsaw (Poland)
4. Department of Physics and Astronomy, University of Manchester, M13 9PL Manchester (United Kingdom)
5. Institute Pluridisciplinaire Hubert Curien, 23 rue du Loess, F-67037 Strasbourg Cedex (France)
6. Argonne National Laboratory, Argonne, Illinois 60439 (United States)

Excited states in {sup 95}Y, populated following the spontaneous fission of {sup 248}Cm and {sup 252}Cf and following fission of {sup 235}U induced by thermal neutrons, were studied by means of {gamma} spectroscopy using the EUROGAM2 and GAMMASPHERE multidetector Ge arrays and the LOHENGRIN fission-fragment separator, respectively. We have found a new (17/2{sup -}) isomer in {sup 95}Y at 3142.2 keV with a half-life of T{sub 1/2}=14.9(5) ns. Another isomer was identified in {sup 95}Y at 5022.1 keV and it was assigned a spin-parity (27/2{sup -}). For this isomer a half-life of T{sub 1/2}=65(4) ns was determined and four decay branches were found, including an E3 decay. A new E3 decay branch was also found for the known, 1087.5-keV isomer in {sup 95}Y, for which we measured a half-life of 51.2(9) {mu}s. The B(E3) and B(E1) transition rates, of 2.0 and 3.8x10{sup -7} W.u., respectively, observed in {sup 95}Y are significantly lower than in the neighboring {sup 96}Zr core, suggesting that octupole correlations in this region are mainly due to the coupling of proton {delta}j=3 orbitals. Shell-model calculations indicate that the (27/2{sup -}) isomer in {sup 95}Y corresponds to the {pi}g{sub 9/2}{nu}(g{sub 7/2}h{sub 11/2}) maximally aligned configuration and that all three isomers in {sup 95}Y decay, primarily, by M2 transitions between proton g{sub 9/2} and f{sub 5/2} orbitals.

• OSTI ID: 21289864
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 4 Vol. 79; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CALIFORNIUM 252
COUPLING
CURIUM 248
E1-TRANSITIONS
EXCITED STATES
FISSION FRAGMENTS
GAMMA SPECTROSCOPY
GE SEMICONDUCTOR DETECTORS
HALF-LIFE
ISOMERIC NUCLEI
KEV RANGE
M2-TRANSITIONS
MEV RANGE 01-10
OCTUPOLES
PARITY
PROTONS
SHELL MODELS
SPIN
SPONTANEOUS FISSION
THERMAL NEUTRONS
URANIUM 235
YTTRIUM 95
ZIRCONIUM 96