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During the slow neutron capture process in massive stars, reactions on light elements can both produce and absorb neutrons thereby influencing the final heavy element abundances. At low metallicities, the high neutron capture rate of $^{16}$O can inhibit s-process nucleosynthesis unless the neutrons are recycled via the $^{17}$O(α,n)$^{20}$Ne reaction. The efficiency of this neutron recycling is determined by competition between the $^{17}$O(α,n)$^{20}$Ne and $^{17}$O(α,γ)$^{21}$Ne reactions. While some experimental data are available on the former reaction, no data exist for the radiative capture channel at the relevant astrophysical energies.The $^{17}$O(α,γ)$^{21}$Ne reaction has been studied directly using the DRAGON recoil separator at the TRIUMF Laboratory. The reaction cross section has been determined at energies between 0.6 and 1.6 MeV Ecm, reaching into the Gamow window for core helium burning for the first time. Resonance strengths for resonances at 0.63, 0.721, 0.81 and 1.122 MeV Ecm have been extracted. The experimentally based reaction rate calculated represents a lower limit, but suggests that significant s-process nucleosynthesis occurs in low metallicity massive stars.

The Li-9 + H-2 reaction has been investigated at 11 AMeV incident energy at the ISAC II facility (TRIUMF). In the present paper we focus on the one-neutron transfer channel, which potentially holds spectroscopic information on the unbound nucleus Li-10. The TUDA setup has been used in order to detect and identify the outgoing Li-9 at forward angles and the recoil protons at backward angles. This setup allows to study the Li-10 emitted in the crucial region at forward angles in the center of mass.

Nucleon transfer experiments have in recent years begun to be exploited in the study of nuclei far from stability, using radioactive beams in inverse kinematics. New techniques are still being developed in order to perform these experiments. The present experiment is designed to study the odd-odd nucleus Na which has a high density of states and therefore requires gamma-ray detection to distinguish between them. The experiment employed an intense beam of up to 3×10 pps of Na at 5.0 MeV/nucleon from the ISAC-II facility at triumf. The new silicon array SHARC was used for the first time and was coupled to the segmented clover gamma-ray array TIGRESS. A novel thin plastic scintillator detector was employed at zero degrees to identify and reject reactions occurring on the carbon component of the (CD) target. The efficiency of the background rejection using this detector is described with respect to the proton and gamma-ray spectra from the (d,p) reaction. © Published under licence by IOP Publishing Ltd.

Active targets are perfect tools for the study of reactions induced by radioactive ion beams of very low intensity. Thus, they make possible the study of direct and compound reactions at the same time. In this talk, we will present the results obtained with the MAYA active target for low energy reactions induced by the halo nucleus 11Li. A method used to measure the mass of short-lived nuclei, applied to the 11Li case will be discussed. The experimantal angular distribution of the two halo-neutron transfer reaction 1H(11Li,9Li)t at 4.3A MeV, using the MAYA detector as a thin target, will be presented and compared to coupled reaction channel calculations including 3-body models in order to extract informations on the structure of the 11Li halo. The extraction of the 11Li+p optical potential using the data on the elastic scattering, will also be discussed. Finally, the excitation function of the resonant elastic scattering reaction, determined using the MAYA detector as a thick target, will be presented. Extraction of information on the structure of possible 12Li isobaric analog states observed in 12Be using several R-matrix calculations will be shown.