Explosive Nucleosynthesis with Unstable Nuclei - Complementary Studies Using Low- and Intermediate-Energy Unstable Nuclear Beams -

利用中能RIKEN环回旋加速器和低能Louvain La Neuve回旋加速器复合体提供的不稳定核束，对爆炸核燃烧过程进行了实验研究。用库仑解离方法对太阳中微子问题的关键过程^&lt；208&gt；Pb(^8B，^7Be，p)^&lt；208&gt；Pb进行了模拟。我们的结果表明很小的E_2组分，理论上估计这会对^8B库仑解离结果造成严重的问题。通过第二次实验，将实现S的新测定。我们还进行了与热pp模燃烧过程有关的^&lt；12&gt；N的离解实验，直接测量了反应^&lt；19&gt；Ne(p，Gamma)^&lt；20&gt；Na。该反应被认为是从CNO到Nena区域的质量流动的关键。实验只能给出横截面的上限，这个上限已经比预测的要小得多。另一种直接测量是对^&lt；13&gt；N(p，Gamma)^&lt；14&gt；O反应进行的，这是从常规CNO循环引燃热CNO循环的关键。这项实验的目的是通过提高数据的准确性，在库仑解离和直接捕获方法之间提供公平和精确的比较，因为这两种方法都曾应用于^&lt；13&gt；N(p，Gamma)^&lt；14&gt；O，结果在误差范围内相互吻合。在Rikkyo建造了一套高效的伽马射线探测装置，并将其带到Louvain la Neuve，测量了放射性~(13)N束与氢靶产生的辐射俘获反应产生的5.17 MeV伽马射线。分析工作正在进行中。

Using beams of unstable nuclei provided by RIKEN Ring Cyclotron with intermediate energies and by Cyclotron complex of Louvain la Neuve with low energies, explosive nuclear burning processes have been studied experimentally. The Coulomb dissociation method was employed at RIKEN for an extensive study of the process ^<208>Pb(^8B,^7Be, p)^<208>Pb, which simulate the ^7Be(p, gamma)^8B reaction, a key process for the solar neutrino problem. Our results suggest very small E2 component, which has been estimated theoretically to cause a serious problem for ^8B Coulomb dissociation results. A new determination of S_<17> will be achieved by the second experiment. We also performed an experiment of ^<12>N dissociation related to the hot pp mode burning process.A direct measurement of the reaction ^<19>Ne(p, gamma)^<20>Na was performed at Louvain la Neuve. This reaction was regarded as a key of mass flow from CNO to NeNa region. The experimental could only give an upper limit of the cross section, which is already much smaller than predictions. Another direct measurement was performed for the ^<13>N(p, gamma)^<14>O reaction, a key to ignite hot CNO cycle from the regular CNO cycle. This experiment was aimed at providing a fair and precise comparison between the Coulomb dissociation and direct capture methods by improving the accuracy of data, because both methods were once applied for the ^<13>N(p, gamma)^<14>O and the results agreed with each other within errors. A gamma-ray detection setup with a high efficiency was build at Rikkyo and brought to Louvain la Neuve to measure 5.17 MeV gamma-rays from the radiative capture reaction induced by radioactive ^<13>N beams with an hydrogen target. Analysis is in progress.