1. |
- CLARK, RM, et al.
(författare)
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A PAIR OF IDENTICAL SUPERDEFORMED BANDS IN ND-136
- 1995
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Ingår i: Physics Letters B. - 0370-2693 .- 1873-2445. ; 343:1-4, s. 59-63
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Nd-136 were populated via the Mo-100(Ar-40, 4n) reaction at beam energies of 176 and 182 MeV, and resulting gamma-rays were detected using the GAMMASPHERE spectrometer. Analysis of the data has revealed the existence of an excited superdeformed (SD) band in Nd-136. Th, yrast SD band in Nd-136 has been extended by the addition of four (possibly five) transitions at high frequency. The new band displays the remarkable property of having transition energies identical (to within +/- 1 keV) to those of the half-points of the yrast SD band of Nd-136. Possible explanations in terms of cranked Woods-Saxon single-particle calculations are discussed.
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2. |
- DELEPLANQUE, MA, et al.
(författare)
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LOW-SPIN TERMINATION OF THE SUPERDEFORMED BAND IN ND-135
- 1995
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 52:5, s. R2302-R2305
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Tidskriftsartikel (refereegranskat)abstract
- The decay of the superdeformed (SD) band in Nd-135 was studied with the early implementation of gamma-sphere. The results suggest that the SD band ''terminates'' at spin 25/2. This termination is explained by a change of the SD minimum toward a triaxial lower deformation. Ultimate cranker calculations with the i(13/2) orbital occupied relate this change to a shift of a proton and neutron pair out of deformation-driving Nilsson orbitals. This is a completely new and unexpected mechanism for the decay of SD bands.
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3. |
- BERNSTEIN, LA, et al.
(författare)
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ONSET OF COLLECTIVITY IN NEUTRON-DEFICIENT PO-196,PO-198
- 1995
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 52:2, s. 621-627
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Tidskriftsartikel (refereegranskat)abstract
- We have studied via in-beam gamma-ray spectroscopy Po-196 and Po-198, which are the first neutron-deficient Po isotopes to exhibit a collective low-lying structure. The ratios of yrast state energies and the E2 branching ratios of transitions from non-yrast to yrast states are indicative of a low-lying vibrational structure. The onset of collective motion in these isotopes can be attributed to the opening of the neutron i(13/2) orbital at N approximate to 112 and the resulting large overlap between the two valence protons in the h(9/2) orbital and the valence neutrons in the i(13/2) orbital.
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4. |
- 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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5. |
- 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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6. |
- Cederwall, Bo, et al.
(författare)
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PROPERTIES OF SUPERDEFORMED BANDS IN DY-153
- 1995
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 346:3-4, s. 244-250
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Tidskriftsartikel (refereegranskat)abstract
- Two new superdeformed (SD) bands in Dy-153, in addition to the three previously observed, have been studied with the GAMMASPHERE detector array. Assignments to single-neutron orbits in the SD potential are made based on the band properties. Evidence for a band interaction at very high spins, possibly involving the first N = 7 proton intruder orbital, is observed in the strongest populated SD band. Furthermore, evidence far a Delta I = 2 staggering is also found in this SD band.
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7. |
- 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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8. |
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9. |
- HENRY, EA, et al.
(författare)
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COLLECTIVE OBLATE BANDS IN PB NUCLEI
- 1993
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Ingår i: Abstracts of Papers of the American Chemical Society. - 0065-7727. ; 206, s. 58-NUCL
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Tidskriftsartikel (refereegranskat)
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10. |
- 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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