Production of 100 Sn in fusion reactions via cluster emission channels
The possibilities of production of the doubly magic nucleus 100 Sn in complete fusion and quasifission reactions with stable and radioactive ion beams are investigated within a dinuclear system model. The excitation functions for production of the exotic nuclei 100−103 Sn via cluster emission channels are predicted for future experiments.
Production of very neutron-deficient isotopes near Sn via reactions involving light-particle and cluster emission
Abstract The production of very neutron-deficient isotopes near 100Sn has been investigated by using on-line mass separation of evaporation residues produced by heavy-ion induced complete-fusion reactions. We measured the cross sections for 99Cd, 100In, 101Sn and 102In via 58Ni+58Ni fusion reactions followed by cluster emission, and via 58Ni+50Cr fusion reactions accompanied by evaporation of protons, neutrons or α particles. Both types of reactions yield similar cross sections for the production of exotic nuclei near 100Sn. The data are discussed in comparison with results obtained from statistical-model calculations.
rp-process nucleosynthesis at extreme temperature and density conditions
We present nuclear reaction network calculations to investigate the influence of nuclear structure on the rp-process between Ge and Sn in various scenarios. Due to the lack of experimental data for neutron-deficient nuclei in this region, we discuss currently available model predictions for nuclear masses and deformations as well as methods of calculating reaction rates (Hauser-Feshbach) and beta-decay rates (QRPA and shell model). In addition, we apply a valence nucleon (NpNn) correlation scheme for the prediction of masses and deformations. We also describe the calculations of 2p-capture reactions, which had not been considered before in this mass region. We find that in X-ray bursts 2p-capture reactions accelerate the reaction flow into the Z greater than or equal to 36 region considerably. Therefore, the rp-process in most X-ray bursts does not end in the Z = 32-36 region as previously assumed and overproduction factors of 10(7)-10(8) are reached for some light p-nuclei in the A = 80-100 region. This might be of interest in respect of the yet unexplained large observed solar system abundances of these nuclei. Nuclei in this region can also be produced via the rp-proces in accretion disks around low mass black holes. Our results indicate that the rp-process energy production in the Z < 32 region cannot be neglected in these scenarios. We discuss in detail the influence of the various nuclear structure input parameters and their current uncertainties on these results. It turns out that rp-process nucleosynthesis is mainly determined by nuclear masses and beta-decay rates of nuclei along the proton drip line. We present a detailed list of nuclei for which mass or beta-decay rate measurements would be crucial to further constrain the models. (C) 1998 Elsevier Science B.V.