J. Styczen

Evidence for low-lying prolate bands in 188Pb and 186Pb

Yrast states of the nuclei 188Pb and 186Pb located in the middle of the 82 < N < 126 shell have been studied for the first time in the reactions 156,154Gd (36Ar, 4n ) at 175 MeV. Gamma rays following the heavy-ion fusion-evaporation reactions were detected in coincidence with evaporation residues. Both nuclei exhibit a structure very different from the heavier even-even lead isotopes and show low-lying, probably prolate rotational bands.

Evidence for the Jacobi shape transition in hot46Ti

The gamma-rays from the decay of the GDR in 46Ti compound nucleus formed in the 18O+28Si reaction at bombarding energy 105 MeV have been measured in an experiment using a setup consisting of the combined EUROBALL IV, HECTOR and EUCLIDES arrays. A comparison of the extracted GDR lineshape data with the predictions of the thermal shape fluctuation model shows evidence for the Jacobi shape transition in hot 46Ti. In addition to the previously found broad structure in the GDR lineshape region at 18-27 MeV caused by large deformations, the presence of a low energy component (around 10 MeV), due to the Coriolis splitting in prolate well deformed shape, has been identified for the first time.

Prolate and oblate 10+ isomers in 140Sm78 and 142Gd78

Abstract The N = 78 isotones 140Sm and 142Gd have been studied with α-particle- and HI-induced reactions. In both nuclei two close-lying 10+ isomers at ∼ 3.2 MeV have been established, and from the feeding E2 cascades they are characterized as the prolate ν h 11 2 −2 and the oblate π h 11 2 2 excitations. A third E2 cascade feeding into the 142Gd 8+ state is interpreted as the continuation of the collective ground state sequence that might assume the properties of a perfect deformed rotor for spins above 10.

Search for the Jacobi shape transition in light nuclei

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Study of Superdeformation in the A ≈ 60 Mass Region; High Resolution γ‐Ray Spectroscopy at EUROBALL IV with the Recoil Filter Detector and the EUCLIDES Charged Particle Detector

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Collective high spin states in 45Sc

-rays following the reaction 105 MeV 18O + 28Si have been measured using the EUROBALL IV, HECTOR and EUCLIDES arrays in order to investigate the predicted Jacobi shape transition. The high-energy

In-beam study of 63 143 Eu80

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Gamow-teller transitions in β-decay of 66 146 Dy80

-ray spectrum from the GDR decay indicates the presence of large deformations in the hot 46Ti nucleus, in agreement with new theoretical calculations based on the rotating liquid-drop model.

Lifetime measurements of high-lying short lived states in 69As

High spin studies of A ≈ 60 nuclei have been carried out with EUROBALL. The nuclei of interest were populated in the fusion‐evaporation reaction with a 125 MeV 16O beam bombarding a thin 56Fe target. The use of the Recoil Filter Detector and the charged particle detector EUCLIDES resulted in a significant reduction of γ‐line widths and facilitated a reaction channel selection. In this article, several new linking transitions of the previously known terminating band in 64Zn are reported. Such bands are also observed in 61Cu and 63Cu. New SD bands identified in 61,63Cu are discussed.

Proton‐neutron interaction and the relative isomer masses in 148Tb

Abstract The high-spin states in 45 Sc were studied with the GASP multidetector array. The nuclei were excited by the 30 Si( 18 O,p2n) 45 Sc reaction at E LAB =60 MeV and separated with the Recoil Mass Spectrometer. Several new high-spin levels extending the known single-particle and collective structures were observed. Energies of the negative-parity states agree with the shell model predictions whereas the positive-parity-intruder rotational band extends up to very high rotational frequencies and continues beyond the maximum angular momentum available from the single-particle f 7 2 configuration.