V. Kroha

Excitation functions for the radionuclide 46 Sc produced in the irradiation of 45 Sc with deuterons and 6 He

Results of the measurements of the excitation function in the deuteron-induced reaction 45 Sc(d,p) 46 Schavebeenobtainedattheenergyofincidentdeuteronsup to11.7MeV.Inaddition, dataforthe 45 Sc(d,t) 44 Screactionwereobtained. The experimentswereperformedusingthevariableenergycyclotronU-120M(NPI, ˇ Reand the Electrostatic Generator EG-5 (FLNP, JINR). The cross sections of the induced activities were measured using the stacked-foil technique. The measured excitation functions were similar to those observed for the 45 Sc( 6 He, 5 He ∗ ) 46 Sc reaction, studied at the accelerator complex for radioactive beams DRIBs (FLNR, JINR). The maximum probability of producing 46 Sc was also found close to the Coulomb barriers of these reactions. The compilation of available experimental data, obtained at deuteron and 6 He-energies near the Coulomb barrier, showed that the values of the cross sections at the maxima of the excitation functions obtained in (d, p) reactions and the reactions for one-neutron pickup from the 6 He projectiles have a different Z-dependence.

Cross sections of 43 Sc, 44 Sc, 46 Sc isotopes formed in the 45 Sc + 3 He reaction

Reactions 45Sc(3He, αn)43Sc, 45Sc(3He, α)44Sc and 45Sc(3He, 2p)46Sc in the 3He energy range of 5 to 24 MeV are investigated in experiments performed with a 3He ion beam during the irradiation of U-120M cyclotron scandium targets. Activation is used to determine the yield of nascent Sc isotopes. The γ activity induced in targets is measured using a high-resolution HPGe detector. The character of the excitation function changes during the formation of these ions and differs from the excitation functions for deuterons, despite the low bond energy of 3He and the positive values of the Q reactions leading to the formation of 44Sc and 46Sc isotopes. The cross sections of 44Sc formation reach their maximum value at the Coulomb barrier of the reaction, due to the stable 4He nucleus that accompanies the formation of 44Sc. The contribution from different reaction mechanisms to the cross sections of 43Sc, 44Sc, and 46Sc isotope formation are considered.

Excitation functions for deuterium-induced reactions on 194Pt near the coulomb barrier

Experiments were carried out at the U-120M cyclotron of the Nuclear Physics Institute of the Czech Republic in Řež using extracted beams of deuterons with energies of 11.7 and 16.4 MeV. The irradiated targets were made of natural Pt and enriched 194Pt. For the two natPt + d and 194Pt + d reactions, cross sections for the production of the isotopes 194Au, 195Au, and 195 mPt near the Coulomb barrier were measured. Calculations of these cross sections at different energies of the deuteron beam were performed with the programs EMPIRE 2.18 and TALYS 1.2. The values calculated for cross sections with a standard set of parameters cannot reliably describe the measured excitation functions for the reactions in the studied range of deuteron energy.

Fusion and transfer cross sections of 3He induced reaction on Pt and Au in energy range 10–24.5 MeV

In experiments performed by accelerated ion 3He-beam irradiated gold and platinum targets on the cyclotron U-120M of the Nuclear Physics Institute of the Czech Academy of Sciences, Řež, reactions of complete and incomplete fusion and nucleon transfer reactions in the 3He energy range from 10 to 24.5 MeV have been investigated. To determine the yield of the nuclides resulting from the nuclear reaction, the activation technique has been used. The obtained data are analyzed using models based on statistical calculations and compared with similar results for other light stable particles. Transfer reactions with positive Q values have relatively high cross sections in the energy range below the Coulomb barrier. These cross sections continue to grow with increasing 3He energy, and, in the case of capturing neutron from target nucleus by a nucleus of 3He, the excitation functions of these reactions reach their maximum almost at the Coulomb barrier of the reactions.

Cross sections for production of 43Sc, 44Sc, and 46Sc isotopes in the 45Sc + 3He reaction

Reactions 45Sc(3He, αn)43Sc, 45Sc(3He, α)44Sc, and 45Sc(3He, 2p)46Sc, resulting from the irradiation of scandium targets with a beam of 3He ions with energy from 5 to 24 MeV, are investigated in experiments on the U120M cyclotron of the Nuclear Physics Institute (Rez, Czech Republic). The activation technique is used to find the yield of the produced Sc isotopes. The induced γ activity in the targets is measured using a high-resolution HPGe detector. Despite the low binding energy of 3He and positive reaction Q values, which leads to formation of the 44Sc and 46Sc isotopes, the behavior of the excitation functions for the formation of these isotopes differs from the behavior of the excitation function for deuterons. Scandium-44 formation cross sections reach their maximum at the reaction Coulomb barrier. This is because not only 44Sc but also a stable 4He nucleus is formed in the reaction.

Study of fusion and nucleon transfer channels in the 197 Au + 6 He reaction in an energy range of 6 He to 20 Mev/A

New data on the cross sections of reactions occurring during the interaction of 6He nuclei with 197Au at energies of 6He from 40 to 120 MeV are presented. The experiments were performed in the ACCULINNA secondary beam separator of the Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research. To identify the reaction products, the activation method for measuring the gamma activity of the target assembly of thin foils was used. The excitation functions for fusion reactions involving the evaporation of up to ten neutrons from the compound nucleus as well as reactions with the emission of charged particles and nucleon transfer in the investigated energy region are obtained. Data analysis was carried out using two codes: ALICE-MP and NRV. The cross sections for the (6He, xn) reactions occurring through the compound nucleus are mostly in agreement with the results of model calculations based on the statistical approach. It is shown that, up to the energies of 114 MeV, the cross-section drop in the complete fusion reactions is negligible. The experimental excitation functions of reactions leading to the formation of isotopes of mercury and gold (transfer reaction) indicate that the main contribution to their formation is made by direct processes and that evaporation reactions (6He, pxn) and (6He, αxn) play a minor role, as is evidenced by a comparison of the measured cross sections with the calculation results.

Cross sections of fusion and transfer reactions in interactions between 3 He and Pt and 197 Au nuclei in the subbarrier energy region

The reactions of complete and incomplete fusion, along with nucleon transfer reactions in the range of 3He energies from 10 to 24.5 MeV, are investigated by irradiating gold and platinum targets with an accelerated 3He ion beam on the U-120M cyclotron at the Institute of Nuclear Physics, Czech Academy of Sciences, Řež. Activation is used to determine the yield of nuclides resulting from nuclear reactions. The γ-activity induced in the targets is measured using a with high-resolution HPGe detector. Despite the low binding energy of 3He and the reactions with positive Q values, the measured cross sections of fusion reactions exhibit no specific features, compared to reactions conducted using beams of other light stable particles. Transfer neutron reactions in the subbarrier energy region have relatively high cross sections. These cross sections continue to grow as the energy of 3He rises. When a neutron is captured by a nucleus of 3He, the cross sections of these reactions reach their maximum values in the Coulomb barrier region.

Investigating the nuclear fusion and nucleon transfer channels in the 197Au + 6He reaction at 6He energies up to 20 MeV/A

New data on the cross sections of reactions that proceed during the interaction of 6He and 197Au nuclei in the 6He energy range of 40 to 120 MeV are reported. The experiments were performed using the secondary beam of the ACCULINNA separator at the Flerov Laboratory of Nuclear Reactions (FLNR), JINR. Reaction products are identified by means of activation method to measure the gamma activity of a thin-foil target assembly. Excitation functions for 6He fusion reactions with subsequent emission of up to 10 neutrons from the compound nucleus are measured. Cross sections for reactions with emission of charged particles and nucleon transfer were also measured. The experimental cross sections for the (6He, xn) reactions that proceed via the formation of a compound nucleus agree in general with calculations using models that involve the statistical approach. It is shown that the complete fusion reaction cross section drops slightly up to an energy of 114 MeV. The experimental excitation functions for the reactions resulting in the formation of mercury and gold isotopes indicate that the main contribution to their formation comes from direct processes, while the evaporation reactions (6He, pxn) and (6He, αxn) are of minor importance.

Excitation functions for 44Sc, 46Sc, and 47Sc radionuclides produced in the interaction of 45Sc with deuterons and 6He

Experimental excitation functions are presented for 45Sc(d, p)46Sc, 45Sc(d, t)44Sc, 45Sc(6He, 5He*)46Sc and 45Sc(6He, α)47Sc reactions at projectile energies near the Coulomb barrier. The obtained excitation functions for reactions 45Sc(d, p)46Sc and 45Sc(6He, 5He*)46Sc have similar behavior and have a maxima near the Coulomb barriers of these reactions. The compilation of the available experimental data, obtained at deuteron- and 6He-energies near the Coulomb barrier, showed that the values of the cross sections at the maxima of the excitation functions obtained in (d, p) reactions and the reactions for one-neutron pickup from the 6He projectiles have a different Z-dependence.

Some Evidence of the Cluster Struture Inside of 9Be

Angular distributions of protons, deuterons, tritons and alpha-particles emitted from the reactions in the H+Be-system at Elab=19.5 MeV were measured with an aim to shed light on the internal cluster structure of Be and the study of possible cluster transfer of He. The analyses suggest a significant contribution of five-nucleon transfer in the reaction channel Be(d,He)Li.