| 1. |
- Lieder, R. M., et al.
(author)
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From highly to superdeformed shapes : study of Gd-143
- 2000
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In: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 671:04-jan, s. 52-70
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Journal article (peer-reviewed)abstract
- A superdeformed band has been discovered in Gd-143 consisting Of 15 transitions. It does not show the band crossing observed in the neighbouring heavier Gd isotopes and it is degenerate with the superdeformed band in Eu-143. In contrast to other degenerate bands at superdeformed shape, the configurations of the bands are quite different here. They result from the exchange of a nu 6(4) with a pi[404]9/2 configuration. In addition, a collective band has been observed which adopts a well-deformed triaxial shape at high spins according to calculations. The transition from highly to superdeformed shapes proceeds via triaxial shapes.
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| 2. |
- Algora, A., et al.
(author)
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Pronounced Shape Change Induced by Quasiparticle Alignment
- 2000
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In: Physical Review C (Nuclear Physics). - 0556-2813 .- 1089-490X. ; 61:3
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Journal article (peer-reviewed)abstract
- Mean lifetimes of high-spin states of Kr-74 have been determined using the Doppler-shift attenuation method. The high-spin states were studied using the Ca-40(Ca-40, alpha 2p) reaction at a beam energy of 160 MeV with the GASP gamma-ray spectrometer. The ground-state band and negative parity side band show the presence of three different configurations in terms of transitional quadrupole deformations. A dramatic shape change was found along the ground-state band after the S-band crossing. The deduced quadrupole deformation changes are well reproduced by cranked Woods-Saxon Strutinsky calculations.
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| 3. |
- Lieder, R. M., et al.
(author)
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Development of magnetic rotation in light Gd nuclei; study of Gd-142
- 2002
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In: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 13:3, s. 297-305
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Journal article (peer-reviewed)abstract
- High-spin states in Gd-142 have been populated by means of the Ru-99(Ti-48, 2p3n) reaction at 2-10 MeV and investigated with the gamma-spectrometer EUROBALL III and the charged-particle detector array ISIS. The features of four dipole bands have been determined and compared with tilted-axis cranking model calculations indicating that they are magnetic rotational bands. A transition from regular to irregular bands has been found approaching N = 82 demonstrating that this is a general phenomenon in nuclei near a double-shell closure.
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| 4. |
- Petrache, C. M., et al.
(author)
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Stable triaxiality at the highest spins in 138Nd and 139Nd
- 2000
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In: Physical Review C - Nuclear Physics. - 0556-2813. ; 61:1, s. 113051-113055
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Journal article (peer-reviewed)abstract
- The nuclei 138Nd and 139Nd have been studied at very high spins via the 48Ca+94Zr reaction. Several new rotational bands were observed, four in 138Nd and two in 139Nd. The J(2) moments of inertia calculated from the observed γ-ray energies are very small and almost constant, indicating that these bands are triaxial. Cranked Nilsson-Strutinsky calculations reproduce the general behavior of the bands, supporting this interpretation and suggesting an approximately constant γ value of ∼ + 35° over a large spin range up to the highest observed spins. These bands and a few similar bands in other nuclei of the N≈80 region are a unique example of almost undisturbed triaxial bands.
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| 5. |
- Spolaore, P., et al.
(author)
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Identification and study of the very neutron deficient nuclide I-111 : search for octupole correlations in the region of N approximate to Z approximate to 56
- 2001
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In: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 682, s. 387C-393C
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Journal article (peer-reviewed)abstract
- High-spin states in the neutron-deficient nuclide I-111 have been populated with the fusion reaction Ni-58 + Ni-58 at a beam energy of 210 MeV, in an experiment performed at the Tandem Accelerator of the Laboratori Nazionali di Legnaro. The gamma spectrometer GASP was used in time coincidence with the ISIS Si-ball and the CAMEL recoil mass spectrometer for the positive identification of the nuclide. Gamma transitions and structure details previously attributed to I-111 by Other authors are only partially confirmed. The obtained level scheme includes new rotational bands and a new low lying structure which suggests the presence of octupole correlations at predicted rotational frequency values.
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| 6. |
- Weiszflog, M., et al.
(author)
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High-spin spectroscopy of Ga-63(31)32 and Ga-65(31)34
- 2001
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In: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 11:1, s. 25-38
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Journal article (peer-reviewed)abstract
- High-spin states in the nuclei Ga-63 and Ga-65 were studied following the reaction S-32 + Ca-40 at a reaction energy of 125 MeV and using the GASP gamma -ray spectrometer in combination with the ISIS charged-particle detector system. In addition to low-lying negative-parity states with single-particle character, rotational-like cascades built on the 9/2(+) and 19/2(-) states have been observed in both nuclei. Sidebands with negative parity in Ga-63 and positive parity in Ga-65 could be established. The experimental results are compared with Total Routhian Surface calculations which describe the nuclei as moderately deformed (beta (2) approximate to 0.25) and gamma soft at low rotational frequencies. The highest experimentally observed positive-parity state in Ga-65 (41/2(+)) is in good agreement with the calculated crossing of the collective band with a non-collective one terminating at this spin.
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| 7. |
- de Angelis, G., et al.
(author)
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Coherent proton-neutron contribution to octupole correlations in the neutron-deficient Xe-114 nucleus
- 2002
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In: Physics Letters B. - 0370-2693 .- 1873-2445. ; 535:04-jan, s. 93-102
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Journal article (peer-reviewed)abstract
- Gamma ray linear polarization and picosecond lifetimes have been measured for levels in the neutron deficient nucleus Xe-114 using the EUROBALL IV spectrometer and the Cologne plunger device. The EUCLIDES Si-ball was used to improve the reaction channel selectivity. The linear polarization results have, for the first time, unambiguously determined the electromagnetic character of the dipole transitions de-exciting the negative parity level sequence, providing clear evidence for enhanced octupole collectivity. The discovery of two E3 transitions and the measurement of the lifetimes of the states depopulated by these transitions have allowed a quantitative determination of the octupole collectivity in the A approximate to 112 mass region. The large measured B(E3) values, close to approximate to 70 W.u., are among the strongest observed hitherto and indicate a coherent proton-neutron contribution to the octupole moment.
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| 8. |
- Lieder, R. M., et al.
(author)
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Investigations of the level scheme of Gd-144 and lifetimes in the quadrupole bands
- 2004
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In: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 21:1, s. 37-55
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Journal article (peer-reviewed)abstract
- For a level scheme investigation of Gd-144 an experiment with the gamma-spectrometer EUROBALL III has been carried out and lifetimes have been measured with the gamma-spectrometer GASP using the Doppler-shift attenuation method. The high-spin states have been populated in these experiments by means of the Mo-100(Ti-48,4n) reaction at 215 MeV and the Cd-114(S-36,6n) reaction at E = 182 MeV, respectively. The known quadrupole band has been modified and a new one has been established. Reduced E2 transition probabilities B(E2) were determined for seven members of these quadrupole bands. They show values between approximate to60 and 130 W.u. and this considerable enhancement gives evidence for a significant nuclear deformation. A (pih(11/2))(2) circle times (vh(11/2))(-2) configuration may be assigned to one of the quadrupole bands according to total Routhian surface calculations. The spin dependence of the B(E2) values has been explained by IBM calculations involving high-spin quasiparticle excitations.
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| 9. |
- Weiszflog, M., et al.
(author)
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High-spin Spectroscopy of 63Ga and 65Ga
- 2001
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In: European Physical Journal A. Hadrons and Nuclei. - 1434-6001. ; 11, s. 25-38
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Journal article (peer-reviewed)abstract
- High-spin states in the nuclei Ga-63 and Ga-65 were studied following the reaction S-32 + Ca-40 at a reaction energy of 125 MeV and using the GASP gamma -ray spectrometer in combination with the ISIS charged-particle detector system. In addition to low-lying negative-parity states with single-particle character, rotational-like cascades built on the 9/2(+) and 19/2(-) states have been observed in both nuclei. Sidebands with negative parity in Ga-63 and positive parity in Ga-65 could be established. The experimental results are compared with Total Routhian Surface calculations which describe the nuclei as moderately deformed (beta (2) approximate to 0.25) and gamma soft at low rotational frequencies. The highest experimentally observed positive-parity state in Ga-65 (41/2(+)) is in good agreement with the calculated crossing of the collective band with a non-collective one terminating at this spin.
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