No abstract available

[en] The β-decay of ¹⁵⁰La, the heaviest isotope of lanthanum, has been identified by observing γ-rays from mass separated activities obtained at KUR-ISOL. From the decay curves of 97.0 and 208.7 keV γ-rays in ¹⁵⁰Ce and of Ce-K_α X-ray, the half-life of ¹⁵⁰La has been determined as 0.51(3) s. This value is in agreement with theoretical predictions from microscopic theory. (orig.)

[en] The foundation of the Strutinsky method within the Hartree-Fock (HF) framework is discussed. Both the basic energy theorem and the energy averaging method are investigated theoretically and numerically. The equivalence of the averaging method with semiclassical expansions is exhibited. Numerical tests of the basic assumptions of the shell-correction approach are presented, which make use of the results of constrained HF calculations for various nuclei and with different effective interactions. The HF energy is decomposed into a smooth part which is shown to be very close to a liquid drop model energy, a first order shell-correction defined in the usual way, and higher order corrections which usually are neglected in standard Strutunsky calculations. These higher order terms are shown not to contribute more than approximately 1-2 MeV to the total energy in medium and heavy nuclei. New results for the nucleus ⁴⁰Ca show that this is no longer the case for light nuclei. Alternative ways of defining the smooth part of the energy are also considered. It is particularly found that if the Strutinsky averaging is performed selfconsistently, the sum of the average energy plus the first order shell-correction extracted from the average potential reproduces perfectly well the exact HF energy. (Auth.)

No abstract available

[en] We propose exotic binary cluster models for the intermediate mass nuclei ^146,148,150Ce and ^{148,150,152,154}Nd. The optimum choice of cluster and core is determined by joint consideration of the penetrability for exotic cluster emission, the deviations of cluster and core binding energies from underlying liquid drop values and the Q-values for breakup. It is noticeable that the core neutron number selected in this way is at or near the N = 82 shell closure. We use a standard form of the cluster-core potential to calculate the energies and wave functions of states in the ground 0⁺, 2⁺, 4⁺, ... and lowest lying negative parity 1^-, 3^-, 5^-, ... bands. The theoretical spectra and electromagnetic properties are compared with measurements, and their general trends are reproduced satisfactorily

No abstract available

[en] The structural evolution of neutron-rich Ce isotopes (Z=58) can be better understood through the knowledge of their low-lying states' lifetimes. The data presented here originate from an experimental campaign carried out at the Argonne National Laboratory (ANL) at the turn of the year 2015/2016, that aimed for the direct measurement of lifetimes of excited states in the ²⁵²Cf spontaneous fission products. The combined usage of one hemisphere of the Gammasphere, consisting of 51 high-resolution HPGe detectors, and an array of 25 ultra-fast LaBr₃(Ce) scintillators from the NuSTAR-FATIMA collaboration, allowed the collection of coincident γ-rays for a period of 30 days. The selection of the Ce isotopes of interest was ensured by posing the necessary amount of energy gates in the HPGe detectors on their characteristic transitions, while the lifetimes in the region from some nanoseconds down to few tens of picoseconds were obtained from the time response of the LaBr₃(Ce) detectors, applying the Generalized Centroid Difference method. In the present work, first results for the lifetimes of the low-lying excited states of ^146-150Ce are shown.

[en] Levels in ¹⁵²Ce are identified for the first time along with new high spin states in ^142-148Ba, ^144-150Ce and ^150-156Nd from X-X, gamma -X and gamma - gamma - gamma -ray coincidence measurement in spontaneous fission of ²⁵²Cf and ²⁴²Pu. The N=88, 90 Ba nuclei have very nearly identical J₁ for the yrast bands (2⁺ to 10⁺) and for the octupole bands (3^- to 15^-). The N=92, 94 Nd nuclei have essentially identical yrast J₁ (0⁺ to 16⁺). (author). Letter-to-the-editor

[en] The β^- decay of ¹⁵⁰Ce having a half-life of 6.05(7) s produced by the thermal-neutron-induced fission of ²³⁵U has been studied using the on-line isotope separator at the Kyoto University Research Reactor. A decay scheme containing 18 excited levels and 55 γ-rays was constructed from γ-ray singles and γ-γ coincidence measurements. Of these, 9 levels and 37 γ-rays were newly placed. The dominant β-feeding observed at the 110 keV level of ¹⁵⁰Pr was found to be an allowed unhindered spin-flip transition. On the basis of the systematics of the neighboring nuclides, the Gallagher-Moszkowski coupling rules, and the selection rules for the β-decay of deformed nuclei, the Nilsson configurations of the ground and 110 keV states in ¹⁵⁰Pr were newly proposed to be π5/2⁺[413]-ν3/2^-[521] and π5/2^-[532]-ν3/2^-[532], respectively. (author)

[en] Short communication