[en] The nuclei in the A ∼ 130 mass region are known to be soft with respect to the triaxial deformation, γ and thus are sensitive to the polarizing effect of specific quasiparticle configuration. This can lead to the coexistence of quadrupole structures which can be determined by the configuration of the valence quasiparticles. The present work is devoted to the investigation of ratio of the quadrupole moment of the isomeric states with spin-parity 11/2"- (τ_1_/_2 = 10ns) and 23/2"+ (τ_1/_2 = 28ns) in "1"3"5La. The time differential perturbed angular distribution (TDPAD) technique was used for these measurements

[en] The β decay of 17.6-h ¹³⁵Ce to levels in ¹³⁵La was studied b γ-ray and conversion-electron spectroscopy, and by extensive γ--γ-coincidence experiments. The use of mass-separated sources, a Compton-suppressed spectrometer, and the megachannel analyzer system for coincidence studies has enabled substantial extension of the experimental knowledge of ¹³⁵La. Seventy-three previously unreported transitions were observed in the singles and coincidence data. Six levels not proposed in earlier works are firmly established here, and two other levels are tentatively proposed. The level structure of ¹³⁵La is compared to the systematics of related nuclei and to qualitative interpretations of nuclear models that attempt to describe this nucleus

No abstract available

[en] The transitional nuclei in the A ∼ 130 mass region with few valence nucleons near shell closure offer to study rich variety of shapes and structures due to interplay of various multi quasi-particle excitations and the collective behavior of underlying core. Many experimental studies based on gamma-ray spectroscopy with heavy ion-induced reactions evidenced mainly high-spin level structures, an outstanding one being that due to the unique parity orbital h_11/2 both for protons and neutrons. The different de-formation driving forces of the valence protons and neutrons occupying low and high states of the h_11/2 intruder orbital leads to phenomenon of shape coexistence. The life-time measurements can help to understand the phenomenon of shape coexistence

No abstract available

[en] The lanthanide elements, due to the very similar chemical properties to those of the actinides, are often employed as chemical analogues of these latter elements, in environmental studies. Lanthanum has been used as carrier of Ac either to avoid coprecipitation with BaSO₄ (hold back carrier) or to be precipitated as La(Ac)F₃ followed by beta count activity. This technique was employed to assess ²²⁸Ra in environmental samples from Morro do Ferro, Pocos de Caldas (MG, Brazil) and the data showed a great variability. In order to find out the source of such diversity in the results obtained, a detailed study of the behaviour of La and Ac was performed in each step of this technique using ¹³⁵La and ²²⁸Ac as tracers and gamma-ray spectroscopy as a measurement technique. The following results were achieved: in the separation step of ²²⁸Ra - ²²⁸Ac(La) by BaSO₄ precipitation, 42-55% of ²²⁸Ac and 13-22% of ¹³⁵La were lost in the BaSO₄ precipitate; in the final step 90-96% of ²²⁸Ac and ¹³⁵La were precipitated as La(Ac)F₃. According to these findings one can conclude that although La does not behave efficiently as hold back carrier for Ac in Ba(Ra)SO₄ precipitation, it works very well in the final separation as La(Ac)F₃. (Author)

[en] The level structures of nuclei evolve from single particle to collective nature, as one goes away from Z=50 and N=82 shell gap. The transitional nuclei around A∼135 with Z > 50 and N < 82 which lie between the spherical and deformed regions show complex and rich level structures due to interplay of single-particle and collective excitation modes. Recently, the isomers in ^135,136La isotopes in this region have attracted lot of attention. With the advancement of large scale shell model calculations, it is now possible to analyze the structures of these isomers. The detailed results on nuclear moment measurements in ^133,135La will be presented in the meeting to understand the structure of the isomers in lanthanum isotopes

[en] The nuclear magnetic moment of a state has contribution from the orbital and spin angular momenta of the unpaired nucleons. Hence, g-factor measurement of an isomeric state can provide the necessary experimental insight to the single particle configuration of the nucleus at high spins. The time differential perturbed angular distribution (TDPAD) measurement is a powerful technique to probe magnetic dipole moment and g-factor of a isomeric states. With this motivation, TDPAD measurement of the 23/2"+ isomeric state in "1"3"5La has been carried out

[en] Short note. 3 refs; 1 fig

[en] The nuclei near A ≅ 135 with the neutron number approaching towards N = 82 shell closure show shape driving effect at high spins with moderate deformation and display a variety of interesting phenomenon such as shape co-existence, Magnetic Rotation (MR) bands and MR band crossing. In the present study, the reinvestigation of the high spin states of ¹³⁵La have been reported