J. Mukai

Signature inversion in 120Cs: Evidence for a residual pn interaction

Abstract High-spin states have been observed in the odd-odd isotope 120Cs in 32S-induced reactions. The previously known band is extended to higher spin and several new bands are identified. Band-head configurations have been inferred by comparing the band properties with known bands in the odd nuclei 121Cs and 121Ba. A remarkable signature inversion is observed in the π h 11 2 ⊗ν h 11 2

Alignment processes in 119Cs, 121Cs and 123Cs

Rotational band structures have been observed in the odd-A Cs isotopes 119Cs, 121Cs and 123Cs. The previously known bands have been extended to higher spin values and several new bands have been es ...

Competing proton and neutron alignments in neutron-deficient Xe-nuclei

Abstract High-spin structures of the neutron-deficient 117,118,120 Xe isotopes have been studied by in-beam γ-ray spectroscopic techniques. The final nuclei have been identified by means of charged-particle detectors. Collective rotational bands based on the neutron d 5 2 , g 7 2 and h 11 2 configurations have been identified in 117 Xe. In the even 118 Xe and 120 Xe nuclei several new side bands were observed and the previously known bands were extended. The present level schemes include two positive-parity bands constructed to high spin in 118 Xe, whereas in 120 Xe three such bands were observed. In order to explain these bands, both proton and neutron ( h 11 2 ) 2 alignments, as well as the shape degree of freedom, have to be invoked. The possible occurrence of a γS-band is addressed and a pronounced structural change for more heavy Xe-isotopes is discussed. All negative-parity side bands are interpreted in terms of proton two-quasiparticle excitations. The experimental data are compared with total routhian surface calculations.

High-spin states in 121Ba and deformation-dependent alignments

The high-spin structure of 121Ba has been investigated by in-beam gamma-ray spectroscopic techniques. Rotational bands based on the h11/2, g7/2 and tentatively d5/2 quasineutron configurations have ...

Evidence for band termination in118Xe

The yrast band of118Xe has been extended up to tentativelyIπ = 34+ in a heavy-ion in-beam γ-spectroscopic study using the NORDBALL detector array. A band crossing is observed at the highest spins and interpreted within the Modified Oscillator Model as a transition to a terminating band.

High-spin states in the odd-odd nucleus 82Y

Abstract High-spin states in 82 Y have been studied by the 58 Ni( 28 Si,3pn) reaction at 128 MeV. Low-lying states were investigated by the same reaction but at a lower bombarding energy and the band heads of the high-spin sequences have been characterized. Four rotational bands forming two sets of signature partners were established. The yrast band was observed up to j π = 27 + and shows (large signature splitting, while a negative-parity yrare band, observed up to spin 22 shows a much smaller splitting. The yrast band structure was very similar to the g 9 2 proton band in 79 Rb.

The ? decay of the new isotope79Y

The neutron deficient isotope79Y has been firstly identified and the decay properties were studied fromΒ-decay measurements in the reaction of54Fe(28Si,p2n at 92 MeV. Threeγ rays of 152.5, 177.4, and 1106 keV were observed concerning theΒ decay. The half life and QEC value were determined to be 14.9 ± 0.6 s and 7.12 ± 0.45 MeV, respectively. The decay scheme including spin-parity is discussed, and 5/2+ assignment for the ground state is proposed.

Neutron and protonh11/2 alignment effects in121La

In a γ-spectroscopic study, excited states in the very neutron deficient nucleus121La have been established for the first time. Rotational bands built on the 9/2+[404] and l/2−[550] Nilsson orbitals are observed up to a maximum spin of tentatively 51/2ħ. The experimental results are compared with Total Routhian Surface calculations.

Signature dependence in the high spin states of128La

High spin states of128La have been investigated by means ofγ ray spectroscopy. Although two level schemes were reported prior to the present study, those schemes were different at excitation energies near the band head. A new level scheme has been obtained for the detailed discussion of signature dependence.

High spin states of120Ba

The very neutron deficient nucleus120Ba has been investigated in a high-spin γ-spectroscopic study. The yrast band of120Ba is extended up to spin 22ħ and one tentatively assigned negative-parity side band is observed up to spin 15ħ. The experimental results are compared with Total Routhian Surface calculations.