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Two reactions of 14O(α,p)17F and 18Ne(α,p)21Na provide the pathways for breakout from the hot CNO cycles to the rp-process in type I X-ray bursts. To better determine their astrophysical reaction rates, resonance parameters of the compound nuclei 18Ne and 22Mg have been investigated by the resonant elastic scattering of 17F+p and 21Na+p, respectively. The 17F and 21Na radioactive ion beams were produced at the CNS Radioactive Ion Beam Separator and impinged on the thick proton targets. The excitation functions were obtained with a thick-target method over a wide excitation energy range. The resonance parameters in the compound nuclei 18Ne and 22Mg have been determined through an R-matrix analysis. New reaction rates of these two (α,p) reactions are recalculated. The astrophysical impact for the 18Ne(α,p)21Na reaction has been investigated through one-zone postprocessing X-ray burst calculations.

Astrophysical 18Ne(α,p)21Na reaction is one of the most probable breakout routes, which lead to the rp-process from the hot-CNO cycle, converting the initial CNO elements into heavier elements in Type I x-ray bursters. Presently, there is no much experimental cross-section data reported at the energy of astrophysical interest, and resonant spectroscopic information in compound 22Mg is scarce as well. The experiment has been carried out by using the CNS radioactive ion beam separator (CRIB). Resonant properties in 22Mg have been studied via the resonant elastic scattering of 21Na+p, and cross section of the time-reversal reaction of 21Na(p,α)18Ne been measured simultaneously. A wide excitation energy region up to Ex ∼ 9.5 MeV in 22Mg has been scanned with a thick-target method. Some preliminary results will be reported.

Resonant properties in 18Ne relevant to the stellar reaction of 14O(α,p)17F have been investigated through a resonant elastic scattering of 17F+p. The 17F RI beam was produced via a projectile-fragmentation reaction, and subsequently separated and purified by a Radioactive Ion beam Line in Lanzhou (RIBLL). After a series of energy degradation, a 4.21 AMeV 17F beam bombarded a thick (CH2)n target at T2 terminal. Energy and angle of the recoiled protons were measured by two sets of ΔE-E silicon telescope at θlab ≈ 0°, 14° respectively. Several resonances in 18Ne were observed, and their resonant parameters including energy, spin-parity and decay width have been determined by an R-Matrix analysis of the experimental excitation function.

Projectile fragmentation reactions have been investigated by the modified statistical abrasion‐ablation model (SAA) and the heavy‐ion phase‐space exploration (HIPSE) model. From the fragment yield ratios, clear isoscaling behavior was observed in the calculated results of the two models. The extracted isoscaling parameters α and β for both heavy and light fragments from HIPSE model calculations are in better agreement with recent experimental data than the SAA model. Assuming a Fermi‐gas behavior, the excitation energy dependence of the symmetry energy coefficients are extracted from α and β, which looks consistent with the experimental data.

We have measured two‐proton momentum and angular correlations for the 23Al excited states from the 23Al radioactive beam on a 12C target at an energy of 60∼70 A MeV at the projectile fragment separator beamline (RIPS) in the RIKEN Ring Cyclotron Facility. The decay products, namely 21Na+p+p from 23Al are clean identified. The relative momentum and opening angle between two protons in the rest frame of three body decay channels demonstrate that there are some diproton emission components from 2He cluster for the excited 23Al.