Heavy ion reactions around the Coulomb barrier

• Published in: Science China. Physics, mechanics & astronomy mechanics & astronomy, 2011-08, Vol.54 (Suppl 1), p.6-13
• Main Authors: Zhang, HuanQiao, Lin, ChengJian, Jia, HuiMing, Zhang, ChunLei, Zhang, GaoLong, Yang, Feng, Liu, ZuHua, An, GuangPeng, Wu, ZhenDong, Xu, XinXing, Jia, Fei
• Format: Article
• Language: English
• Subjects: Angular distribution; Astronomy; Classical and Continuum Physics; Coupling; Deformation effects; Elastic analysis; Elastic scattering; Excitation; Fission; Heavy ions; Inelastic scattering; Lead isotopes; Mathematical models; Nuclear cross sections; Observations and Techniques; Parameters; Physics; Physics and Astronomy; Q values (nuclear physics); Research Paper; Zirconium isotopes
• ISSN: 1674-7348; 1869-1927
• DOI: 10.1007/s11433-011-4419-5

The angular distributions of fission fragments for the 32 S+ 184 W reaction near Coulomb barrier energies are measured. The experimental fission excitation function is obtained. The measured fission cross sections are decomposed into fusion-fission, quasi-fission and fast fission contributions by the dinuclear system (DNS) model. The hindrance to completing fusion both at small and large collision energies is explained. The fusion excitation functions of 32 S+ 90,96 Zr in an energy range from above to below the Coulomb barrier are measured and analyzed within a semi-classical model. The obvious effect of positive Q -value multi-neutron transfers on the sub-barrier fusion enhancement is observed in the 32 S+ 96 Zr system. In addition, the excitation functions of quasi-elastic scattering at a backward angle have been measured with high precision for the systems of 16 O + 208 Pb, 196 Pt, 184 W, and 154,152 Sm at energies well below the Coulomb barrier. Considering the deformed coupling effects, the extracted diffuseness parameters are close to the values extracted from the systematic analysis of elastic and inelastic scattering data. The elastic scattering angular distribution of 17 F+ 12 C at 60 MeV is measured and calculated by using the continuum-discretized coupled-channels (CDCC) approach. It is found that the diffuseness parameter of the real part of core-target potential has to be increased by 20% to reproduce the experimental result, which corresponds to an increment of potential depth at the surface region. The breakup cross section and the coupling between breakup and elastic scattering are small.