V. Bondarenko

Excited levels of Ho166

Abstract The internal conversion electron spectrum in the reaction Ho165(n, γ)Ho166 has been measured with a β-spectrograph. Within the energy interval 40–300 keV, energies and intensities of conversion electron lines have been determined. The scheme of low-energy levels in Ho166 is discussed. The characteristics 3−, 4− are proposed for the levels at 170.6 keV and 240.1 keV instead of assignments existing in the literature.

Structure of the Odd‐Odd Nucleus 188Re

Thermal neutron capture gamma-ray spectra for {sup 187}Re(n,{gamma}){sup 188}Re reaction were measured. Singles and coincidence spectra were detected in order to develop the level scheme. The evaluation is in progress, of which the first results are obtained from the analysis of coincidence spectra, allowing to check the level scheme below 500 keV excitation energy. Seven low-energy negative parity bands are developed in order to find better energies for rotational levels. With a good confidence, a few positive parity bands are developed as well. Rotor plus two quasiparticle model calculations, employing effective matrix element method are performed for the system of six negative parity rotational bands.

Nuclear structure of 181Hf studied in (n, γ) and (d, p) reactions

The level structure in 181Hf is studied by using (n, γ) and (d, p) reactions. Gamma-gamma coincidences permit an unambiguous placement of the majority of gamma transitions in the level scheme up to 1.8 MeV, while the (d, p) angular distributions and vector analyzing powers are used to deduce spin-parity assignments. Forty-three levels are grouped into 12 rotational bands built on one-quasiparticle and quasiparticle-plus-vibrational states. The proposed level structures are in qualitative agreement with earlier quasiparticle-phonon-model calculations.

Systematic Studies of Odd Isotopes in the Vicinity of the Closed Shell Z=50

The isotopes in vicinity of the closed shell Z=50, the long chain of odd Te isotopes from 119Te to 131Te, 125Sn and 123Sn, have been investigated by means of (d,p), (dpol,p), (dpol,t), (3He,α) and (n,γ) reactions. The experimental data were interpreted within the framework of Interacting Boson Fermion Model (IBFM) and Quasiparticle Phonon Model (QPM).The isotopes in vicinity of the closed shell Z=50, the long chain of odd Te isotopes from 119Te to 131Te, 125Sn and 123Sn, have been investigated by means of (d,p), (dpol,p), (dpol,t), (3He,α) and (n,γ) reactions. The experimental data were interpreted within the framework of Interacting Boson Fermion Model (IBFM) and Quasiparticle Phonon Model (QPM).

Nuclear spectroscopy of odd Te isotopes

The odd-A Te isotopes, 119–131Te, have been investigated via (d,p), (p,p), (d,t), (3He,α) and (n,γ) reactions. The application of polarized deuterons in the (d,p) and (d,t) reaction allowed us to construct essentially complete level schemes with spin and parities up to about 2÷3 MeV. On the other hand, the measurement of γ−γ coincidences in the (n,γ) reaction enable us to place most of the γ transitions in the decay schemes of the odd Te isotopes. The experimental systematics of both positive and negative parity low-lying states for the whole odd Te chain are reasonably well described with Interacting Boson-Fermion Model-1 with an essentially constant boson-fermion interaction. The combination of the neutron transfer reactions and (n,γ) reaction helps us to understand the origin of the anomalous population of the long-lived isomers in odd-A Te isotopes. The evidence for the direct process mechanism in 127Te, 129Te and 131Te was observed.

Spectroscopy of 129Te

The nucleus 129Te has been investigated via (d,p), (d,t) and (n,γ) reactions. The new data allowed to locate the 122+ level at 773.2 keV and a new 5/2− level at 1221.3 keV. The latter is depopulated by the strong and so far unplaced 756 keV transition, making it an important gateway for the 11/2−-isomer population.