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

利用RIKEN加速器研究所的RIPS束流课程提供的快RI束流，我们测量了热pp模式，热CNO循环和rp过程中的几个反应。还进行了实验以检验库仑解离方法的有效性。本文研究了与太阳中微子问题有关的^8B库仑离解的反应机制。1用库仑离解方法研究了热pp模式下的^8B（p，γ）^9C，^<11>C（p，γ）^<12>N和^<12>N（p，γ）^<13>O反应。结果与热pp模的网络计算中所用的结果有很大的不同。[2]<13>我们研究了^ N通过其1/2^+态的库仑离解。从测量的截面中提取出辐射宽度Γ_γ=0.51±0.04 eV。它与直接测量的一致性，0.50±0.04 eV，证明了该方法的有效性。3<15>在6.793 MeV下测量了^ 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。4测量^ A1的库仑解离<23>以确定^<22>Mg（p，y）^<23>A1反应。E2向第一激发态的跃迁被认为在rp过程中很重要，这与Wiescher等人的评价一致，尽管误差很大。[5]我们分析了^8B库仑解离在宽角度范围内的截面。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.