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When a neutron star accretes hydrogen and helium from the outer layers of its companion star, thermonuclear burning enables the α p-process as a break out mechanism from the hot CNO cycle. Model calculations predict ( α , p) reaction rates significantly affect both the light curves and elemental abundances in the burst ashes. The Jet Experiments in Nuclear Structure and Astrophysics (JENSA) gas jet target enables the direct measurement of previously inaccessible ( α ,p) reactions with radioactive beams provided by the rare isotope re-accelerator ReA3 at the National Superconducting Cyclotron Laboratory (NSCL), USA. JENSA is going to be the main target for the Recoil Separator for Capture Reactions (SECAR) at the Facility for Rare Isotope Beams (FRIB). Commissioning of JENSA and first experiments at Oak Ridge National Laboratory (ORNL) showed a highly localized, pure gas target with a density of ∼10 19 atoms per square centimeter. Preliminary results are presented from the first direct cross section measurement of the 34 Ar( α , p) 37 K reaction at NSCL.

Reactions on certain proton-rich, radioactive nuclei have been shown to have a significant influence on X-ray bursts. We provide an overview of two recent measurements of important X-ray burst reactions using in-flight radioactive ion beams from the RESOLUT facility at the J. D. Fox Superconducting Accelerator Laboratory at Florida State University. The 17 F(d,n) 18 Ne reaction was measured, and Asymptotic Normalization Coefficients were extracted for bound states in 18 Ne that determine the direct-capture cross section dominating the 17 F(p, γ ) 18 Ne reaction rate for T≲ 0.45 GK. Unbound resonant states were also studied, and the single-particle strength for the 4.523-MeV (3 + ) state was found to be consistent with previous results. The 19 Ne(d,n) 20 Na proton transfer reaction was used to study resonances in the 19 Ne(p, γ ) 20 Na reaction. The most important 2.65-MeV state in 20 Na was observed to decay by proton emission to both the ground and first-excited states in 19 Ne, providing strong evidence for a 3 + spin assignment and indicating that proton capture on the thermally-populated first-excited state in 19 Ne is an important contributor to the 19 Ne(p, γ ) 20 Na reaction rate.

International audience; The Galactic 1.809-MeV γ-ray signature from the β decay of $^{26g}$Al is a dominant target of γ-rayastronomy, of which a significant component is understood to originate from massive stars. The$^{26g}$Al(p; γ)$^{27}$Si reaction is a major destruction pathway for $^{26g}$Al at stellar temperatures, but the reactionrate is poorly constrained due to uncertainties in the strengths of low-lying resonances in $^{27}$Si. The$^{26g}$Al(d; p)$^{27}$Al reaction has been employed in inverse kinematics to determine the spectroscopic factors,and hence resonance strengths, of proton resonances in $^{27}$Si via mirror symmetry. The strength of the127-keV resonance is found to be a factor of 4 higher than the previously adopted upper limit, and the upperlimit for the 68-keV resonance has been reduced by an order of magnitude, considerably constraining the$^{26g}$Al destruction rate at stellar temperatures.

The extraction of detailed nuclear structure information from transfer reactions requires reliable, well-normalized data as well as optical potentials and a theoretical framework demonstrated to work well in the relevant mass and beam energy ranges. It is rare that the theoretical ingredients can be tested well for exotic nuclei owing to the paucity of data. The halo nucleus Be-11 has been examined through the 10Be(d,p) reaction in inverse kinematics at equivalent deuteron energies of 12,15,18, and 21.4 MeV. Elastic scattering of Be-10 on protons was used to select optical potentials for the analysis of the transfer data. Additionally, data from the elastic and inelastic scattering of Be-10 on deuterons was used to fit optical potentials at the four measured energies. Transfers to the two bound states and the first resonance in Be-11 were analyzed using the Finite Range ADiabatic Wave Approximation (FR-ADWA). Consistent values of the spectroscopic factor of both the ground and first excited states were extracted from the four measurements, with average values of 0.71(5) and 0.62(4) respectively. The calculations for transfer to the first resonance were found to be sensitive to the size of the energy bin used and therefore could not be used to extract a spectroscopic factor., 16 Pages, 10 figures

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.

A high-density supersonic gas-jet target named JENSA (Jet Experiments in Nuclear Structure and Astrophysics) has been constructed and commissioned at Oak Ridge National Laboratory. The target creates a localized (∼ 4 mm wide) thick (∼10 19 atoms/cm2) concentration of gaseous atoms (H, He, N, etc...) that are suitable for use in high-resolution experiments with radioactive beams. The interaction point of the beam with the gas-jet target is surrounded by silicon strip detectors from the SuperORRUBA (Oak Ridge Rutgers University Barrel Array) to detect reaction products with good energy (∼30 keV) and angular resolution (∼1 degree). Initial experiments are discussed along with plans for future use at Michigan State University.