| 1. |
- Cederwall, Bo, et al.
(författare)
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NEW FEATURES OF SUPERDEFORMED BANDS IN HG-194
- 1994
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 72:20, s. 3150-3153
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Tidskriftsartikel (refereegranskat)abstract
- Two new features of superdeformed (SD) bands in the A almost-equal-to 190 region emerge from a study of Hg-194 with the Gammasphere detector array. A decrease of the dynamic moment of inertia is observed for rotational frequencies HBARomega greater-than-or-equal-to 0.4 MeV, confirming long standing expectations based on mean field calculations with pairing. Evidence for a small staggering in the SD transition energies is also observed, suggesting the presence of terms with fourfold symmetry in the SD Hamiltonian.
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| 2. |
- Cederwall, Bo, et al.
(författare)
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NEW OBLATE BAND IN HG-196 WITH QUENCHED M1 STRENGTH
- 1993
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 47:6, s. R2443-R2446
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in the nucleUs Hg-196 were populated in the reaction (Os(Be,5n))-Os-192 at a beam energy of 65 MeV. A regular rotational-like DELTAI = 1 band has been observed up to an excitation energy of E* almost-equal-to 8.7 MeV and spin I almost-equal-to 30hBAR. This is the second observation of a band of this character in a mercury isotope. The experimental results are compared with mean field calculations and semiclassical estimates based on the Donau-Frauendorf formalism. The mercury bands show significantly lower B(M1)/B(E2) branching ratios as compared with similar bands in light lead nuclei. This difference may be more readily explained by a difference in single-particle structure rather than by large differences in deformation between the lead and mercury configurations.
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| 3. |
- FALLON, P, et al.
(författare)
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EVIDENCE FOR M1 TRANSITIONS BETWEEN SUPERDEFORMED STATES IN HG-193
- 1993
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 70:18, s. 2690-2693
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Tidskriftsartikel (refereegranskat)abstract
- Two-way decay has been observed between superdeformed bands in Hg193. it is proposed the decays have M 1 multipolarity and connect signature partner bands. Candidates for the two-way gamma decays connecting superdeformed bands are observed for the first time.
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| 4. |
- HUGHES, JR, et al.
(författare)
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EXCITATIONS IN DOUBLY-MAGIC SUPERDEFORMED PB-194
- 1994
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 50:3, s. R1265-R1269
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Tidskriftsartikel (refereegranskat)abstract
- A new superdeformed band with an intensity similar to 5% relative to the yrast superdeformed band has been observed in Pb-194. Evidence for a second new band corresponding to the signature partner is also presented. These bands were observed with GAMMASPHERE early implementation via the Yb-174(Mg-25, 5n) reaction at a beam energy of 130 MeV. The rotational characteristics of the new bands suggest an interpretation involving particle-hole excitations in the doubly-magic Pb-194 superdeformed core. The results are compared to neighboring nuclei and recent theoretical calculations, and possible configurations are suggested.
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| 5. |
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| 6. |
- HUGHES, JR, et al.
(författare)
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LIFETIME MEASUREMENT IN EXCITED AND YRAST SUPERDEFORMED BANDS IN HG-194
- 1994
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 72:6, s. 824-827
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Tidskriftsartikel (refereegranskat)abstract
- Nuclear level lifetimes have been measured in two superdeformed bands in Hg-194 using the Doppler-shift attenuation method. Average transition quadrupole moments derived from the life-times of an excited and yrast superdeformed bands are Q(t) = 17.6(30) and 17.2(20) eb, respectively. The Doppler shifts of the excited band relative to the yrast band indicate a slight difference in quadrupole moments [+4(5)%], assuming similar side feeding. These results imply that the second well is stable and rigid with respect to the particle excitation responsible for this excited band.
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| 7. |
- HUGHES, JR, et al.
(författare)
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LIFETIME MEASUREMENTS IN THE REGULAR DELTA-I = 1 OBLATE BAND IN PB-197
- 1993
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 48:5, s. R2135-R2139
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Tidskriftsartikel (refereegranskat)abstract
- Lifetimes of states in the regular DELTAI = 1 band in 197Pb have been measured with the Doppler-shift attenuation method. Excited states in 197Pb were populated using the Sm-154(48Ca, 5n) reaction at E(b) = 210 MeV. The target consisted of 1 mg/cm2 Sm-154 evaporated onto a 10 mg/cm2 Au backing. Discernible lineshapes for gamma rays in the energy range 300 < E(gamma) < 500 keV in the regular band were observed in a spectroscopic study with the 20 Ge-detector array, HERA. Level lifetimes were obtained from a lineshape analysis. Averaged reduced transition strengths, B(M1) approximately 1.7 W.u. and B(E2) approximately 18 W.u., are deduced and these are compared with theoretical predictions for the suggested configuration of this band.
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| 8. |
- VO, DT, et al.
(författare)
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SUPERDEFORMATION IN AU-191
- 1993
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 71:3, s. 340-343
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Tidskriftsartikel (refereegranskat)abstract
- A superdeformed band has been observed for the first time in an Au isotope. The reaction used was B-11 + W-186, demonstrating that very light ions can be used to populate superdeformed (SD) bands at high angular momentum. The band is assigned to 191Au. The gamma-ray energies are at the quarter-point energies of the 192Hg SD band, indicating that it is ''identical'' to that of 192Hg.
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