High-spin spectroscopy of ^{140}Nd

Lifetime measurements on the high-spin rotational bands in 133 Nd have been carried out by the Doppler-shift attenuation method using the GASP array. The 133 Nd nuclei were populated in the 104 Pd( 32 S,2pn) reaction at a bombarding energy of 135 MeV. The Doppler-broadened line shapes were analyzed for Au-backed and Gd-backed targets. Values of Q t ϭ4.7(5), 5.6͑5͒, and 7.4(4) e b have been determined for the mean transitional quadrupole moments of the ground-state band, the negative-parity band involving the neutron h 9/2 / f 7/2 intruder orbitals, and the band built on the neutron ͓660͔1/2 ϩ intruder orbital, respectively. The presently determined quadrupole moments are compared with those of the low-spin members of the bands derived elsewhere from recoil distance method measurements. The observed polarizing effects of the neutron intruder orbitals are compared with cranked shell model predictions.

Medium and high-spin states in 133 Ce were investigated using the 116 Cd(22 Ne, 5n) reaction and the Gammasphere array. The level scheme was extended up to an excitation energy of ∼22.8 MeV and spin 93/2. Eleven bands of quadrupole transitions and two new dipole bands are identified. The connections to low-lying states of the previously known, high-spin triaxial bands were firmly established, thus fixing the excitation energy and, in many cases, the spin parity of the levels. Based on comparisons with cranked Nilsson-Strutinsky calculations and tilted axis cranking covariant density functional theory, it is shown that all observed bands are characterized by pronounced triaxiality. Competing multiquasiparticle configurations are found to contribute to a rich variety of collective phenomena in this nucleus.

Nuclear Physics A, 1996

-spin spectroscopy of the 142Eu, 143Eu and 144Eu nuclei M. Piiparinen a'b, A. Ataq a,c, j. Blomqvist d, G.

Nuclear Physics A, 2004

The high spin states in the N = 80 odd-A 141 Pm nucleus have been investigated by in-beam γ-spectroscopic techniques following the reaction 133 Cs(12 C, 4n) 141 Pm at E = 65 MeV using a modest γ detector array, consisting of seven Compton-suppressed high purity germanium detectors and a multiplicity ball of 14 bismuth germanate elements. Thirty new γ rays have been assigned to 141 Pm on the basis of γ-ray singles and γ γ-coincidence data. The level scheme of 141 Pm has been extended upto an excitation energy of 5.2 MeV and spin 35 2h and 16 new levels have been proposed. Spin-parity assignments for most of the newly proposed levels have been made on the basis of the deduced directional correlation orientation ratios for strong transitions. The meanlives of a few excited states have been determined from the pulsed beam-γ γ coincidence data using the generalised centroid-shift method. The level structure is discussed in the light of known systematics of neighbouring N = 80 isotonic nuclei.

Physics Letters B, 1991

Science China Physics, Mechanics and Astronomy, 2010

High spin states of 84 Sr were populated through the reaction 70 Zn(18 O, 4n) 84 Sr at 75 MeV beam energy. Measurement of excitation function, γ-γ coincidences, directional correlation from oriented state (DCO) ratios and γ-transition intensities were performed using eight anticompton HPGe detectors and one planar HPGe detector. Based on the measured results, a new level scheme of 84 Sr was established in which 12 new states and nearly 30 new γ-transitions were identified in the present work. The positive-parity states of the new level scheme were compared with the results from calculations in the framework of the projected shell model (PSM). One negative-parity band was extended to spin I π =19 − and it can be found that in the high spin states, the γ-transition energies show the nature of signature staggering. The negative-parity band levels are in good agreement with deformed configuration-mixing shell model (DCM) calculations.

Physics Letters B, 1989

Intermediate energy proton scattering has been used to probe the spin part of the recently discovered low-lying isovector magnetic dipole transitions in the rotational rare earth nuclei ~56Gd and 164Dy. A large spin response is found in 164Dy, whereas in ~56Gd the results are consistent with the picture of a predominantly convective excitation. The results are discussed in the context of the IBA-2 model and recent RPA calculations.

Physical Review C, 2012

Five N = 82 isotones have been produced in two fusion-fission reactions and their γ rays studied with the Euroball array. The high-spin states of 139 La have been identified for the first time, while the high-spin yrast and near-to-yrast structures of the four others have been greatly extended. From angular correlation analysis, spin values have been assigned to some states of 136 Xe and 137 Cs. Several cascades involving γ rays of 139 La have been found to be delayed, they deexcite an isomeric state with T 1/2 = 315(35) ns located at 1800-keV excitation energy. The excited states of these five N = 82 isotones are expected to be due to various proton excitations involving the three high-j subshells located above the Z = 50 shell closure. This is confirmed by the results of shell-model calculations performed in this work. In addition, high-spin states corresponding to the excitation of the neutron core have been unambiguously identified in 136 Xe, 137 Cs, and 138 Ba.

Nuclear Physics A, 1985

The collective and non-collective high-spin configurations in selected A = 80 nuclei are analysed in detail using a shell-correction approach taking care of individual configurations and the pairingself-consistent cranking method with a non-axially-deformed Woods-Saxon potential. Shape transitions, shape coexistence, band-termination effects and alignment processes are discussed.

Levels excited up to 39.8 MeV and 119/2 units of angular momentum have been populated in 125 Xe by the 82 Se(48 Ca,5n) 125 Xe reaction. High-fold γ-ray coincidence events were measured using the Gammasphere Ge detector array. Nine regular rotational bands extending from levels identified previously up to almost 60 ¯ h have been identified, and three of these have been connected to low-lying levels having well-established spins and parities. Configurations have been assigned to six of the bands based on alignment properties, band crossings, and comparison with theoretical cranked shell model calculations (CSM). Transition quadrupole moments have been measured for these bands in the spin range 31−55 ¯ h and were found to be in agreement with the CSM calculations. The corresponding quadrupole deformation 2 ranges from 0.28 to 0.34 at a γ deformation of 0 • and from 0.29 to 0.36 at a γ value of 5 • .