0000000000288686
AUTHOR
T. Krasta
showing 9 related works from this author
Formation of dislocations in LiF irradiated with 3He and 4He ions
2018
Influence of the irradiation with 13.5 MeV 3He and 5 MeV 4He ions on the micro-structure and mechanical properties of LiF single crystals was studied. The depth profiles of nanoindentation, dislocation mobility, selective chemical etching and photoluminescence served for the characterization of damage. Strong ion-induced increase of hardness and decrease in dislocation mobility at the stage of track overlapping due to accumulation of dislocations and other extended defects was observed. At high fluences (1015 ions/cm2) the hardness saturates at about 3.5 GPa (twofold increase in comparison to a virgin crystal) thus confirming high efficiency of light projectiles in modifications of structur…
New rotational levels in $^{186}$Re nucleus
2020
International audience; Excited levels of 186 Re have been studied using results of the single γ -ray spectra measurements following the thermal neutron capture reaction. Energies and intensities of more than 500 γ -transitions have been obtained with the high-resolution crystal diffraction spectrometer GAMS5 of ILL. Most of the obtained intense γ -transitions have been placed in the 186 Re level scheme. A number of new levels, as well as the depopulation for levels observed earlier in the 187 Re (p,d)186 Re reaction measurements have been proposed. Structure of 186 Re levels is interpreted in terms of two-quasiparticle plus rotor coupling model and compared with that of the neighbouring do…
Gamma bands in doubly odd rhenium and iridium nuclei
2015
Structure of the |K ± 2| bands in doubly-odd nuclei belonging to the transitional deformation region at A∼190 is discussed. Relation of these quasi gamma-bands with the non-axial deformation of the parent two- quasiparticle configurations is studied. Using available experimental information, new tentative |K ± 2| bands are proposed in 188 Re, and 192,194 Ir nuclei. Coexistence of two-quasiparticle states with different deformation modes is considered in the case of 188 Re and 194 Ir.
Natural Radioactivity in Clay and Building Materials Used in Latvia
2015
Abstract This paper presents the results of natural radionuclide concentration and activity index study in materials used for construction in Latvia. Special attention is given to clay and clay ceramics. Concentrations of K-40 and Th- 232, U-238 radioactivity were determined using gamma-spectrometry method. In some building ware, maximal concentration of K-40 was 1440 Bq/kg, and of U-238 - 175 Bq/kg. In granite, the determined maximum concentration of Th-232 was 210 Bq/kg. It was found that radionuclide content in different period clay deposits can differ by more than two times, and up to five times in different clay ceramics. The results obtained are compared with analogous data from the o…
Low-lying levels of 188Re nucleus from γγ-coincidence measurements
2010
Low–high and low–low energy γγ-coincidences, following the Re187(n,γ)Re188 reaction with thermal neutrons, have been measured. Spectra have been recorded in the energy range from 50 to 2600 keV, and from 4500 to 6500 keV. The earlier known 188Re level scheme is corrected and extended up to ∼800 keV excitation energy and 62 levels by including 20 new levels. For 11 levels, the earlier interpretation has been changed. The complete level scheme is presented for up to ∼400 keV energy and spins ⩽5. Core plus two-quasiparticles model calculations have been performed. Some 188Re two-quasiparticle states display features indicating the nuclear shape phase transition from axial-deformation to γ-soft…
Levels of 188Re nucleus populated in thermal neutron capture reaction
2016
Abstract Levels of 188 Re populated in thermal neutron capture reaction with enriched 187 Re targets have been studied. Single γ -ray spectrum of 188 Re, measured with the high-resolution crystal diffraction spectrometer GAMS5, as well as γγ -coincidence experiments performed with high efficiency Ge detectors, allowed to develop model-independent level scheme of the doubly-odd 188 Re nucleus up to ∼ 1.5 MeV excitation energy. Analysis of the established 188 Re level scheme in terms of the quasiparticle-plus-rotor model indicates coexistence of axially-deformed and triaxial structures in the energy range above 400 keV.
Levels of 186Re populated in thermal neutron capture reaction
2015
Levels of 186 Re have been studied in the thermal neutron capture reaction with an enriched 185 Re target. Evaluation of spectrum measured with GAMS5 allowed to obtain energies and intensities of more than 500 γ -lines assigned to 186 Re. Most of the obtained transitions have been placed in the model-independent level scheme of the doubly odd 186 Re nucleus, taking into account the available data of earlier experiments as well as the results of recent 187 Re(p, d )186 Re reaction measurements. Structure of the 186 Re low-lying levels has been analysed in terms of the particle-plus-rotor coupling model.
Classification of basis states for (p-f)-nuclei (41 <= A <= 80) with minimal configuration energy
2003
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Levels of two-particle and gamma bands in 192 Ir
2015
Abstract Level scheme of the transitional doubly odd nucleus 192 Ir is analysed in detail up to about 530 keV energy using earlier published experimental data of neutron capture and particle transfer reactions. A number of new levels are proposed. Obtained 192 Ir level scheme is interpreted in terms of particle-plus-rotor coupling model. It is shown that the long-lived 241 year isomer of 192 Ir has spin-parity 11 − , just like the analogous states in neighbouring 190,194 Ir.