Measurements of thermonuclear reaction rates for light nuclei with intermediate-energy RI beams

利用RIKEN加速器研究设施RIPS光束课程提供的快速RI光束，我们测量了热pp模式，热CNO循环和rp过程中的几种反应。通过实验验证了库仑解离法的有效性。研究了与太阳中微子问题有关的^8B库仑解离的反应机理用库仑解离法研究了热pp模式下^8B(p,γ)^9C、^<11>C(p,γ)^< 12>n和^< 12>n (p,γ)^< 13>o的反应。结果与热pp模式的网络计算结果有很大的不同研究了^<13>N通过1/2^+态的库仑解离。从测量截面中提取辐射宽度Γ_γ=0.51±0.04 eV。与直接测量值吻合0.50±0.04 eV，证明了该方法的有效性在6.793 MeV下测量了^<15>O到其3/2+态的非弹性散射。提取了转移概率的上限。结果表明，状态对CNO循环核燃烧的影响很小测量^<23>A1的库仑解离，以确定^<22>Mg(p,y)^<23>A1反应。E2跃迁到第一激发态在rp过程中被认为是重要的，与Wiescher等人的评价一致，但误差较大对^8B库仑解离在宽角范围内的截面进行了分析。结合我们的GSI实验在较高入射能量下获得的数据，预计E2跃迁的混合物很小。

Using the fast RI beams provided by the RIPS beam course at RIKEN Accelerator Research Facility, we measured several reactions in the hot pp-mode, hot CNO cycle, and rp process. An experiment to test the validity of the Coulomb dissociation method was also performed. The reaction mechanism of the ^8B Coulomb dissociation, which is related to the solar neutrino problem, was investigated.1 The reactions in the hot pp mode, ^8B(p,γ)^9C, ^<11>C(p,γ)^<12>N, and ^<12>N(p,γ)^<13>O, were studied by the Coulomb dissociation. The results were considerably different from what have been used in network calculations for the hot pp mode.2 The Coulomb dissociation of ^<13>N through its 1/2^+ state was studied. From the measured cross section, the radiative width Γ_γ=0.51±0.04 eV was extracted. Its agreement with direct measurements, 0.50±0.04 eV, demonstrates the validity of the method.3 Inelastic scattering of ^<15>O to its 3/2+ state at 6.793 MeV was measured. An upper limit of the transition probability was extracted. The result suggests only small influence of the state to the CNO cycle nuclear burning.4 Coulomb dissociation of ^<23>A1 was measured to determine the ^<22>Mg(p,y)^<23>A1 reaction. The E2 transition to the first excited state, which is considered to be important in the rp-process, was consistent with the evaluation by Wiescher et al., thouth the error is large.5 Cross sections in a wide angular range for the ^8B Coulomb dissociation was analyzed. Together with the data obtained by our GSI experiment at a higher incident energy, the mixture of the E2 transitions was expected to be small.