[en] The half life of the 5/2^- (532) intrinsic state in ¹⁵¹Pm, ¹⁵³Eu and ¹⁵⁵Eu has been determined by the delayed coincidence method. The absolute E1, ΔK = 0 transition probabilities between the 5/2^- (532) -> 5/2⁺ (413) intrinsic states have been deduced and compared with theoretical predictions, using the Nilsson model as a starting point. The effect on the predicted transition probabilities obtained by adding pairing correlations and Coriolis coupling have also been studied. It has been found that the experimental transition rates, which are still strongly enhanced, cannot be explained by these contributions alone. It is therefore suggested that collective dipole contributions like those arising through the octupole excitations are of importance

[en] Neutron-rich ^147,149,151Pr nuclei, produced in the spontaneous fission of ²⁵²Cf, were studied using the Gammasphere array. Possible parity doublets in ¹⁴⁷Pr with N=88 and πh_11/2 bands in ^149,151Pr are proposed. These new data on the level structures of odd Pr isotopes suggest that octupole correlations may also be present in the neutron-rich ₅₉¹⁴⁷Pr₈₈ nucleus such as those observed in ₅₈¹⁴⁶Ce₈₈, and also that the h_11/2 bands in the ^149,151Pr track in energy the yrast bands in ^148,150Ce. The backbending related to the breaking of the neutron i_13/2 pair is observed at ℎω∼0.27 (MeV) for the proton h_11/2 band of ¹⁴⁹Pr

[en] The β-decay of ₅₉¹⁵¹Pr₉₂ to the levels in ₆₀¹⁵¹Nd₉₁ has been studied from the fission products of ²³⁵U using an on-line isotope separator (KUR-ISOL). Gamma-rays and conversion electrons have been measured. Conversion coefficients have been determined for the first time. The precise decay scheme is proposed up to 2430 keV. The newly observed 65 γ-rays and 16 levels are incorporated in it. The deduced level scheme of ¹⁵¹Nd was compared to the calculated level scheme on the basis of the rotation-vibration coupling model with a Nilsson potential. Low-lying levels were well reproduced by this model. (author)

[en] By the development of oxidation method by Kawase et al., the ISOL of the Kyoto University research reactor was improved largely in its efficiency of ion source, consequently, the fission products with mass number more than 150 have become to be taken out strongly. The authors have carried out the nuclear spectroscopy of rare earth nuclei using the ISOL. By the oxidation method, the strong beam of A=152+16 was taken out using the ISOL, and the β-ray and the internal conversion electrons of Nd-152 and the β-ray of its daughter nuclei Pm-151 were measured. Besides, as for the decay from Pr-151 to Nd-151, its Q_β value is expected to be about 4 MeV, but the level from the decay has been reported only up to 880 keV. As for Pr-151, also the detailed decay scheme was made, and the coordination of 59th proton from the decay to Nd-151 was examined. The γ-ray single and the γ-γ coincidence measurements of Pr-147, Pr-151 and Nd-152, the β single and the β-γ coincidence measurements of Pr-151 and Nd-152, and the β-γ delayed coincidence measurement of Pr-147 and Pr-151 were carried out. The combined use of chemical separation method was done. The results are reported. (K.I.)

[en] Using axially symmetric deformed configuration mixing and angular momentum projection techniques, we have studied the signature effects in the πh_11/2 bands of ¹⁴⁷La, ¹⁴⁹Pr, and ¹⁵¹Pm nuclei. Effects of rotation alignment on the signature splitting in energy and signature inversion in the B(E2,I→I-1) values are discussed. We find that transition from a strongly rotation-aligned limit to a weakly rotation-aligned (or more regular rotational behavior) regime or vice versa leads to signature inversion of the B(E2) values

No abstract available

[en] Decay studies on ¹⁵¹Ce have been performed using the on-line isotope separator connected to the Kyoto University Reactor. In addition to conventional γ and conversion electron spectroscopy, β-gated measurements were carried out on mass-separated ¹⁵¹Ce to identify an isomeric transition. From the analysis of the obtained data, the half-life of the isotope was ascertained to be 1.76(6)s and a decay scheme containing six excited levels was constructed for the first time. The excited level at 35.1keV in ¹⁵¹Pr was found to be a long-lived state (a half-life of approximately 10μs or longer)

[en] The level scheme of ¹⁵¹Pm populated by the β-decay of 12 min ¹⁵¹Nd has been studied using Ge(Li) detectors as singles and coincidence γ-ray spectrometers. Most of the new γ-rays have been included in a partial level scheme of ¹⁵¹Pm involving four new levels. Angular correlation measurements on the 170.752-255.678 keV and 170.752-138.882 keV cascades have been made with the result A₂=0.088+-0.005 and -0.02-+0.05, respectively. A PAC measurement on the 170.752-255.678 keV cascade has yielded the g-factor of the 255.676 keV level as g=1.18+-0.16. A Nilsson-model calculation including Coriolis coupling has been made and the experimental level energies have been well reproduced by the Nilsson orbitals [413](spin down), [411](spin up), [420](spin up), [532](spin up), [541](spin up), and [550](spin up). Theoretical transition rates, E2/M1 mixing ratios, branching ratios and g-factors are in good agreement with experimental values

[en] The β^--decay of ¹⁵¹Pr produced by the thermal neutron-induced fission of ²³⁵U has been studied using an on-line isotope separator. From an internal-conversion electron measurement with a Si(Li) detector, K-conversion coefficients were obtained for 20 γ-transitions. Spins and parities of 6 excited levels in ¹⁵¹Nd were newly determined from the deduced multipolarities: even parities for the 543 and 627 keV levels, odd parities for 250 and 599 keV, (3/2, 5/2)⁺ for 685 keV, and (1/2, 3/2)⁺ for 880 keV. The level structure was compared with the rotation-vibration coupling Nilsson model. (orig.)

[en] Published in summary form only