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High-spin states of 194 Pb have been populated by the reaction 184 W( 16 O, 6n) at 113 MeV beam energy and studied using the EUROGAM-1 array. The level scheme has been extended up to spin of 33 ℏ and excitation energy of 11.1 MeV. The high-spin part of the level scheme is dominated by bands of dipole transitions. New dipole bands have been observed and the configurations of their band heads are discussed. Besides the well-known coupling of the K π =11 − two-proton state to several νi 13/2 rotation-aligned neutron states, the K π =8 + two-proton state is also involved. Such a coupling is identified for the first time in a lead isotope. Moreover, the K π =11 − two-proton state is coupled to the rotation-aligned proton pair ( πh 11/2 ) 2 . Thus many multiparticle configurations involving all the high- j subshells located around the proton and neutron Fermi levels, πh 11/2 , πh 9/2 , πi 13/2 , and νi 13/2 have been identified in this nucleus.

Dipole transitions linking the superdeformed Yrast signature-partner bands in 195Tl have been observed using the EUROGAM 1 spectrometer. From the measurements of the photon decay branching ratios, taken together with the average quadrupole moment measured in neighbouring superdeformed nuclei, we find that the two signature partner superdeformed bands involve the excitation of the 81 st proton into the i 13 2 Ω= 5 2 intruder orbital

The complete spectrum of [gamma] rays following the decay of superdeformed (SD) states in [sup 192]Hg has been extracted. The spectrum, which comprises a quasicontinuous component and sharp lines, reveals the decay mechanism and defines the excitation energies of the SD band. The decay of SD states results from the coupling between a cold, ordered SD system with a hot, chaotic one with normal deformation.

The192Hg nucleus was populated in the160Gd(36S, 4n) reaction at a beam energy of E=159 MeV. Emittedγ-rays were detected with the EUROGAM array comprising 43 Compton-suppressed large volume Ge detectors. The level scheme of192Hg has been extended up to an excitation energy of E=10.4 MeV and spin I=34 ħ. Two new structures, made of competing ΔI=1 and ΔI=2 transitions have been observed and their connexions with the low-lying levels established. Their lowest levels are located at 6.304 MeV and 6.879 MeV excitation energy. The experimental results are compared with mean-field HF+BCS calculations. It is proposed that the new structures originate from deformation-aligned quasi-proton excitations π(i13/2 * h9/2)K=11 andπ (h9/2) K=8 2 , coupled to rotation-aligned quasi-neutron ν(i13/2)n and quasi-proton π(h11/2)2 excitations.

Two regular dipole gamma -ray cascades have been observed in 194Pb. A comprehensive level scheme related to these structures has been built and first members of rotational bands built on K=8 and K=11 two-proton oblate states have been identified. From the excitation energies, spin values, behaviours of the moments of inertia and alignments, and from the comparison with the isotone 192Hg, multiparticle configurations can be attributed to three high-spin structures of 194Pb built respectively on the 4966 keV, 4334 keV and 6198 keV levels: ( pi 9/2(505) pi 13/2(606))(vi13/2)2, ( pi 9/2(505) pi 13/2(606))(vf5/2vi13/2), ( pi 9/2(505) pi 13/2(606)) (vf5/2(vi13/2)3). Within this interpretation, the regular dipole bands correspond to the presence of two or three i13/2 decoupled neutrons.

The nucleus 193Pb was populated via the 168Er(30Si,5n) reaction at a beam energy of 159 MeV and studied with the EUROGAM II spectrometer. Five new dipole Δ I = 1 cascades have been found. These structures have been connected to the level scheme which has been considerably extended up to a spin of ħ and an excitation energy of about 8 MeV. Angular distribution coefficients, a2, have been measured and confirm the dipole character of the in-band transitions. B(M1)/B(E2) ratios have been extracted for the two most intense cascades. The 193Pb dipole bands are discussed in comparison with those known in odd lead isotopic series and the structure of the band heads is analyzed in terms of microscopic HF+BCS calculations. The proposed configurations are based on a high-K two quasiproton excitation, π ([505]9/2t? ⊗ [606]13/2+)K=11t-, coupled to one or three rotation aligned quasineutrons involving the i13/2, p3/2, f5/2 and/or h{9/2} subshells. The main difference, compared with the heavier lead isotopes, is the presence of large Ω orbitals from the ν (i13/2) shell near the Fermi surface which are responsible for the increasing band-head spin as A decreases.

An excited superdeformed (SD) band has been observed in 192Hg with the UROGAM spectrometer. It is interpreted as a two quasi-neutron excitation in the 192Hg SD nucleus. Nuclear level lifetimeshave been measured using the Dopple-shift attenuation method. An average transition quadrupole moment of 19.5 ± 1.5 b has been obtained which is similar to the value measured in the yeast SD band. These results indicate that the deformation in the 192Hg SD nucleus is stable despite changes in the occupancy of high-N-orbitals.

The nucleus 193Pb was populated via the 168Er(30Si, 5n) reaction at a beam energy of 159 MeV and studied with the EUROGAM II spectrometer. Five new dipole ΔI = 1 cascades have been found. The 193Pb dipole bands are discussed in terms of microscopic HF+BCS calculations. The proposed configurations are based on a high-K two-quasiproton excitation coupled to rotation aligned quasineutrons. Parallel to the dipole bands the six superdeformed bands have been discussed in the framework of microscopic mean-field calculations. The bands are interpreted as three pairs of signature partners based on quasineutron excitations. Cross-talk transitions linking two signature partner superdeformed bands have been observed and, for the first time in lead isotopes, a mean B(M1)/B(E2) ratio value of 0.15±0.04 μ N 2 /e2b2 has been extracted.

We have carried out an experiment using the reaction168Er (30Si, 5n)193Pb at a beam energy of 159MeV with EUROGAM 2 to study the superdeformed (SD) bands in193Pb. We have observed some discreteγ rays which are possible candidates for links between the yrast SD band and the low-lying levels in this odd lead isotope. These data suggest for the lowest state of the SD band 1 an excitation energy of 4217±2 keV and a spin of (23/2−).

The 192Hg nucleus has been produced via the 36S(160Gd, 4n) reaction at a beam energy of 159 MeV. The γ-rays have been detected with the multi-detector array EUROGAM phase 1. The level scheme has been extended up to 10.4 MeV excitation energy and spin 34. Two new structures, composed of competing ΔI = 1 and ΔI = 2 transitions, have been observed and, for the first time in Mercury isotopes, some links with the previously known low-lying states have been established. These experimental results are discussed in terms of mean-field Hartree-Fock plus BCS calculations and the new bands are proposed to originate from deformation-aligned quasi-proton excitations. π(i13/2 * h9/2)kπ=11 and π(h9/2)2kπ=8+ coupled to rotation-aligned quasi-neutrons v(i13/2)n and quasi-proton π(h11/2)2 excitations.

Angular distributions for the elastic scattering of /sup 40/Ca by /sup 40/Ca at E/sub c. m./ = 64.8, 71.8, 88, 93, 112.5, and 120 MeV and excitation functions at 60/sup 0/, 70/sup 0/, and 90/sup 0/ (c.m.) over the c.m. energy range 55--120 MeV have been measured. Strong-absorption-model and optical-model analyses are presented. The predictions of several theoretical interaction potentials are compared with the data. The absence of structure in the excitation functions is studied and explained by the large mass and charge of the colliding nuclei.

Inelastic scattering of 84 Kr on 232 Th has been measured at E =371 and 450 MeV and at different angles using the particle-gamma coincidence technique. It is found that for distances of closest approach smaller than about 20 fm the scattering of Kr on Th is mostly inelastic. At forward angles, the data are in agreement with predicted values from a Coulomb excitation program, but some differences are observed at backward angles.

Coulomb excitation experiments have been performed on the two stable odd-mass tellurium isotopes using a N 3+ beam from the Orsay cyclotron. The reduced excitation probabilities of the following levels: 439.2 keV (3/2 + ) and 505.2 keV (5/2 or 3/2 + ) in 123 Te, 443.5 keV(3/2 + ), 463.4 keV (5/2 + ) and 671.3 keV (5/2 + ) in 125 Te were measured by this method. Some B (E2) and B (M1) transition probabilities are deduced from experiments. The results are discussed in terms of de Shalit's model and Kisslinger and Sorensen's calculations.