[en] In this article, we shall report our recent experimental studies on high spin states of very neutron deficient La (N=64), Ba (N=64-66), Cs (N=65-66) isotopes

[en] Various interesting features like shape transition, shape co-existence, octupole deformation etc have been predicted in the mass region A ≅120. In this respect an experiment has been performed to populate high spin states of the neutron deficient Cs and La isotopes like ¹¹⁹Cs, ¹²¹La, using ³²S bombarding on ⁹²Mo target. The TRS calculations has been done for ¹¹⁹Cs isotope and a shape transition from prolate to oblate has been observed. Similar calculation is being done for the La isotopes. In this article all these theoretical and experimental results will be presented

[en] Short communication. 2 refs., 3 tabs

[en] This thesis reports several in-beam γ-ray spectroscopic studies of rotational states in neutron deficient nuclei in the transitional A = 120 and A = 170 mass regions following heavy-ion reactions. The experiments were performed using high-resolution multidetector arrays at Daresbury Laboratory, England and the Tandem Accelerator Laboratory, Niels Bohr Institute, Denmark. The Daresbury Recoil Separator and a 4π charged particle Si-detector system in conjunction with 11 neutron detectors were used in order to identify some of the very neutron deficient and previously unknown residual nuclei that were produced in the reactions. The experimental results are compared to theoretical mean field calculations which minimize the total energy of the nucleus as a function of rotational frequency and deformation, for various configurations. Within the limitations of these so called Total Routhian Surface (TRS) calculations it is possible to draw conclusions of the underlying microscopic mechanisms behind the experimentally observed properties of rotational band structures. The emphasis is put on studies of the shape polarizing properties of different single-particle orbits, especially on the role of deformed intruder states. (39 refs.) (au)

[en] A new isotope of ¹²¹La was produced in the reaction ³²S+⁹²Mo and mass-separated as ¹²¹La¹⁶O⁺, being well separated from ¹²¹Cs and ¹²¹Ba. From γ-ray measurement, the half-life of this isotope was determined to be 5.3±0.2 s. Its partial decay scheme is proposed. (orig.)

[en] The 2000 Nuclear Data Sheets for A = 121 by T. Tamura, with literature cutoff date of July 1,1999 has been updated. The experimental results from various decays and reactions for A=121 mass chain have been compiled and evaluated. The nuclides covered in this evaluation are from ¹²¹Rh to ¹²¹Pr. The data are summarized and presented, together with adopted level schemes.

[en] To strengthen elemental selectivity in isotope separation on-line, ionization of the monoxides of light lanthanoids in a thermal ion source has been studied. Currents of the monoxide ion MO⁺ and the metallic ion M⁺ were measured in off-line experiments using oxide reagents of the elements from Ba to Sm at ion-source temperatures from 1900 to 2730 K. The observed MO⁺/M⁺ ratio was the highest for La and Ce, and decreased with increasing atomic number and temperature. In on-line experiments using heavy-ion fusion-evaporation reactions, La isotopes were mass-separated as La¹⁶O⁺, being well separated from the Cs and Ba isobars, while Pr isotopes were obtained at a higher temperature as Pr⁺ since the La and Ce isobars were still ionized favorably as MO⁺. Using this method, the isotope ¹²¹La was newly identified with a half-life of 5.3±0.2 s. (orig.)