N. K. Skobelev

Isomeric ratios for ^{196,198}{\rm Tl} and ^{196,198}{\rm Au} from fusion and transfer in the interaction of 6He with 197Au

Excitation functions and isomeric cross-section ratios have been measured for the isomeric pairs 198m,gTl, 196m,gTl, 198m,gAu and 196m,gAu, formed in fusion–evaporation and transfer processes in reactions of 6He with 197Au in the energy range 7–60 MeV. The population probability of high- and low-spin states in the fusion reaction with the formation of 198Tl and 196Tl (Jπm = 7+, Jπg = 2−), as well as of the transfer products 198Au and 196Au (Jπm = 12−, Jπg = 2−) is compared with calculations within the statistical model and with similar results, obtained in reactions induced by other nuclei.

Complete and incomplete fusion of 6Li ions with Bi and Pt

Experimental excitation functions are presented for fusion–evaporation and transfer reactions in the interaction of 6Li with Bi and Pt targets. The data on the cross sections obtained for the produced evaporation residues are in agreement with calculations within the framework of the statistical model using the ALICE-MP code. Enhancement of the cross section for deuteron transfer reactions is observed at energies below the Coulomb barrier. The results are discussed from the point of view of how the nuclear cluster structure influences the probability of interaction at near-barrier energies.

Elastic scattering of a secondary 11Li beam on 28Si at 29 MeV/nucleon

Abstract The elastic scattering of a secondary 11 Li beam (29 MeV/nucleon) on a 28 Si target has been measured for the first time. To compensate for the low intensity of the secondary beam, an efficient detecting system permitting one to obtain reliable experimental data has been used. An attempt has been made to reproduce the data in a phenomenological analysis and with coupled-channel calculations with a double-folding optical potential, with energy- and density-dependent effective interaction and realistic densities. In coupled-channel calculations with the folding optical potential a better description is achieved if a neutron halo of 11 Li is taken into account.

Quasielastic scattering of light exotic nuclei. A semi-microscopic folding analysis

Abstract Angular distributions and total reaction cross sections for the quasielastic scattering of (i) 8 B and 7 Be on 12 C at E lab = 40 MeV/nucleon, (ii) 11 Li on 28 Si at E lab = 29 MeV/nucleon, and (iii) 11 C and 11 Li on 12 C at lab = 60 MeV/nucleon are studied with coupled-channels calculations using double-folding optical potential based on the M3Y effective interaction and densities obtained within the energy-density functional approach with a fixed parameter set for all colliding nuclei. An imaginary part of the optical potential is constructed from folding the real one with two free parameters for volume and surface absorption. It is shown that a fairly good description of the experimental data can be achieved within a rather restricted range of these free parameters without renormalization of the real part of the optical potential. The analysis confirms the long neutron tail (halo) in 11 Li and supports a rather thick proton skin in 8 B and, to a lesser extent, in 7 Be.

The response of a large CsI(Tl) detector to light particles and heavy ions in the intermediate energy range

Abstract Particle dependent response of a CsI(Tl) scintillation detector with an entrance surface of 314 cm2 has been investigated using a secondary beam facility at the energy range from 2 to 77 MeV/A. The mass and charge identification of particles with Z = 1–18 has been performed by means of time-of-flight and energy measurements. The dependence of light output on E, Z and A has been studied. Using a pulse shape analysis possibility to identify the masses of momentum separated particles with charges of Z = 1–7 is presented.

DRIPLINE NUCLEI PRODUCED BY QUASI-FRAGMENTATION OF THE 32,34,36S PRIMARY BEAMS

Some regularities in the production of isotopes with are investigated in reactions induced by beams at on targets , and . A search for using a beam of the neutron-rich has been performed. Evidence for particle instability of was obtained. In the same experiment, the half lives of the very neutron-rich isotopes and were measured for the first time.

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.

Fission of209Bi induced by6He ions

Secondary beams of4He and6He were produced through the transfer reactions with the 18.5 MeV/u11B and 35.5 MeV/u7Li primary beams. The fusion-fission cross sections have been measured for the4,6He +209Bi reactions at energies Ecm>1.5*Bfus. In the present experiment it was found that the fission excitation function for the neutron rich nuclei6He is significantly higher than for the4He nuclei.

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.