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Underground Nuclear Astrophysics in China (JUNA) will take the advantage of the ultra-low background in Jinping underground lab. High current accelerator with an ECR source and detectors were commissioned. JUNA plans to study directly a number of nuclear reactions important to hydrostatic stellar evolution at their relevant stellar energies. At the first period, JUNA aims at the direct measurements of 25Mg(p,γ)26 Al, 19F(p,α) 16 O, 13C(α, n) 16O and 12C(α,γ) 16O near the Gamow window. The current progress of JUNA will be given.

The 13N+p elastic resonance scattering has been studied at the secondary radioactive beam facility of CIAE in inverse kinematics via a thick-target method. The excitation function for the 13N(p,p) scattering was obtained in the energy interval of Ecm ≈ 0.5–3.2 MeV with a 13N secondary beam of (47.8±1.5) MeV. Careful analysis of the secondary beam components and extensive Monte–Carlo simulations enable the resolution of the experimental proton spectra. The resonance parameters for five low-lying levels in 14O were deduced by R-matrix fitting calculations with MULTI7 and SAMMY-M6-BETA. The present results show general agreement with those from a recent similar work, and thus confirm the observation of a new 0− level at 5.7 MeV in 14O with an improved width of 400(45) keV.

The elastic resonance scattering of 12C+p has been studied in inverse kinematics via a novel thick target method at GIRAFFE facility of HI-13 tandem accelerator laboratory, Beijing. The recoil protons were measured by a ΔE-E counter telescope based on a large area double-sided silicon strip detector at laboratory angles around θ0 = 15°. The excitation function for 12C(p,p) elastic scattering has been obtained over a wide energy range of Ec.m.=0.31–3.45 MeV, which was explained quite well by the R-matrix calculation with known resonance parameters of the first three levels in 13N nucleus. Thus it is demonstrated that the present setup can be directly applied to the study of elastic resonance scattering with secondary radioactive beams.

The neutron capture reaction on a neutron-rich near closed-shell nucleus 82Ge may play an important role in the r-process following the fallout from nuclear statistical equilibrium in core-collapse supernovae. By carrying out a DWBA analysis for the experimental angular distribution of 82Ge(d, p)83Ge reaction we obtain the single particle spectroscopic factors, S2,5/2 and S0,1/2 for the ground and first excited states of 83Ge = 82Ge?n, respectively. And then these spectroscopic factors are used to calculate the direct capture cross sections for the 82Ge(n, ?)83Ge reaction at energies of astrophysical interest. The optical potential for neutron scattering on unstable nucleus 82Ge is not known experimentally. We employed a real folding potential which was calculated by using the proper 82Ge density distribution and an effective nucleon-nucleon force DDM3Y. The neutron capture reactions on neutron-rich closed-shell nuclei are expected to be dominated by the direct capture to bound states. We will show that the direct capture rates on these nuclei are sensitive to the structure of the low-lying states.

The 8Li(p, d)7Li reaction plays an important role in the inhomogeneous Big Bang nucleosynthesis and in the seed-nuclide production phase for the r-process. For the first time, its angular distribution at backward angles was measured in inverse kinematics at Ec.m. = 4.0 MeV by using an 8Li secondary beam. The result of measurement includes the contributions of 8Li(p, d0)7Li and 8Li(p, d1)7Li*. The 8Li(p, d0)7Li component is estimated to be 40%~58% in the mixture angular distribution by analysing the measured result.

The asymptotic normalization coefficients (ANCs) for the virtual decay 17O→16O+n are derived from the angular distributions of the 16O(d,p)17O reaction leading to the ground and first excited states of 17O, respectively, using the distorted wave Born approximation and the adiabatic wave approximation. The ANCs of 17F are then extracted according to charge symmetry of mirror nuclei and used to calculate the astrophysical S-factors of 16O(p,γ)17F leading to the first two states of 17F. The present results are in good agreement with those from the direct measurement. This provides a test of this indirect method to determine direct astrophysical S-factors of (p,γ) reaction. In addition, the S-factors at zero energy for the direct captures to the ground and first excited states of 17F are presented, without the uncertainty associated with the extrapolation from higher energies in direct measurement.

Based on the angular distribution of the 8Li(d,n)9Beg.s. reaction at Ec.m. = 8.0 MeV and distorted wave Born approximation analysis, the single particle spectroscopic factor S1,3/2 for the ground state of 9Be = 8Li⊗p is derived to be 0.64 ± 0.21. In addition, we deduce the astrophysical S-factors and rates of the 8Li(p,γ)9Beg.s. direct capture reaction at energies of astrophysical interests.

The asymptotic normalization coefficient of the virtual decay 27P → 26Si + p is extracted to be 1840±240 fm−1 from the peripheral 26Mg(d,p)27Mg reaction using charge symmetry of mirror pair, for the first time. It is then used to derive the rms radius of the valence proton in the ground state of 27P. We obtain the rms radius r21/2 = 4.57±0.36 fm, significantly larger than the matter radius of 27P. The probability of the valence proton outside the matter radius of 27P is found to be 73%. The present work supports the conclusion that the 27P ground state has a proton halo structure.

The angular distribution of the 2H(8Li, 9Be)n (ground state) reaction, important to primordial nucleosynthesis in the inhomogeneous model, has been measured at Ec.m. = 8.1 MeV using a secondary 8Li beam. Cross section of this reaction was determined to be 9.0±3.4 mb. According to the cross section, the astrophysical S-factor was calculated to be 272±103 keV b. It is shown that 2H(8Li, 9Be)n (ground state) reaction is important for creating 9Be, but less important for destroying 8Li in primordial nucleosynthesis.

A radioactive ion beam facility, GIRAFFE, has been built at the CIAE HI-13 Tandem accelerator. The facility makes use of the inverse kinematics. A D-Q-Q type magnetic separation and focusing system was used in the beam line. This simple device is expected to yield some radioactive ion beams(A 5 –10 6 pps). The ion beams of 7 Be, 11 C and 17 F were delivered, and the 7 Be beam was applied for two experiments.

The angular distributions of the charge exchange reaction 1H(6He, 6Li)n were measured in reverse kinematics with a secondary 6He beam at the energy of 4.17 A MeV. The data were analysed in the context of a microscopic calculation. It is shown that both the ground state of 6He and the second excited state of 6Li (3.563 MeV, 0+) have a halo structure.

The mass of 40Ti has been determined by using the isobaric multiplet mass equation method. The experimental data of the 40Ti β-decay were used to determine the level of the isospin analogue state of 40Sc. The ground-state mass excess and the QEC value for 40Ti were determined to be -9060±12 keV and 11 466 ± 13 keV, respectively.

Angular distribution of the 6He(d,n)7Li reaction at Ec.m.=9.1 MeV is measured in inverse kinematics for the first time. The proton spectroscopic factors for the ground and first excited states of 7Li are derived by using the distorted wave Born approximation analysis. The astrophysical rates of 6He(p, ?)7Li reaction are then deduced and fitted with an expression of REACLIB.

The elastic resonance scattering of 17F+p is studied in inverse kinematics via a thick-target method. The excitation function for 17F+p elastic scattering is obtained within the energy interval of Ec.m. ~ 0.4–1.7 MeV. The experimental excitation function is analyzed with a multilevel R-matrix code MULTI7, and the proton widths are deduced. The α decay from 6.15 MeV 1− state in 18Ne is observed, which is critical to the 14O(α, p)17 F reaction as the main breakout route from CNO cycle to rp-process in supernovae and x-ray bursts.

Angular distribution of the 12C(6He, 7Li)11B transfer reaction is measured with a secondary 6He beam of 36.4 MeV for the first time. The experimental angular distribution is well reproduced by the distorted-wave Born approximation (DWBA) calculation. The success of the present experiment shows that it is feasible to measure one-nucleon transfer reaction on a light nucleus target with the secondary beam facility of the HI-13 tandem accelerator at China Institute of Atomic Energy (CIAE), Beijing.