W. Meczynski

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.

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.

Probing the Order-to-Chaos Region in Superdeformed {sup 151}Tb and {sup 196}Pb Nuclei with Continuum {gamma} Transitions

The gamma decay associated with the warm rotation of the superdeformed nuclei 151Tb and 196Pb has been measured with the EUROBALL IV array. Several independent quantities provide a stringent test of the population and decay dynamics in the superdeformed well. A Monte Carlo simulation of the gamma decay based on microscopic calculations gives remarkable agreement with the data only assuming a large enhancement of the B(E1) strength for 1-2 MeV gamma rays, which may be related to the evidence for octupole vibrations in both mass regions.

Search for the Jacobi shape transition in light nuclei

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Shell model and octupole states in148Gd from in-beam experiments

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Population Of Neutron Rich Nuclei Around 48Ca With Deep Inelastic Collisions

-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

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

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Reaction dynamics and nuclear structure studies via deep inelastic collisions with heavy-ions: spin and parity assignment in 49Ca

-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.

Reaction Dynamics And Nuclear Structure Via Deep Inelastic Collisions With Heavy-Ions: Search For Particle-Vibration Couplings in [sup 49]Ca

Through (α, 4n) and (τ, 3n) reactions the high-spin states in the two-neutron nucleus148Gd were populated up toIπ=21− at 7.2 MeV, including numerous states above the yrast line. The148Gd energy spectrum is interpreted in terms of the spherical shell model. Identification of the (νf7/2i1 3/2)10− state gives the νi13/2 single particle energy free of octupole admixtures as 2.1(1) MeV. Eight high-spin states between 1.2 and 3.7 MeV were identified as the couplings of the two valence-particles to the146Gd octupole phonon, and three above-lying levels are assigned as double-octupole excitations including a 12+ state which decays by anE3-E3 stretched cascade. All these octupole levels can be quantitatively predicted from the one-particle x phonon spectrum of147Gd. The high-spin states above 3 MeV are four-quasiparticle excitations ofπ+1π−1ν2 andπ2ν2 type and their energies are in good accord with shell model estimates.

A Study of the Jacobi Shape Transition in Light, Fast Rotating Nuclei with the EUROBALL IV, HECTOR and EUCLIDES Arrays

The reaction 48Ca+64Ni has been studied in the deep inelastic regime at approximately 6 MeV/A, by the CLARA‐PRISMA setup. Angular distributions of the reaction cross sections have been obtained for the most intense reaction products, taking into account the response function of the magnetic spectrometer. The response of PRISMA has been calculated making use of a MonteCarlo simulation of the transport of the ions in the spectrometer, starting from known events distributions. For the one‐nucleon transfer channels, the experimental data are in good agreement with predictions from a semiclassical multi‐nucleon transfer model.