Investigation of the Early Stage of the Explosive Hydrogen Burning in the Universe

在本项目下，开发了一种低能RI束分离器CRIB，它在日本首次成功地为研究涉及不稳定核的爆炸燃烧下的恒星反应提供了独特的机会。现将本项目所完成的工作总结如下：(1)主要为本项目研制QMDQDMQ+WF结构的低能RI束流飞行分离器CRIB。在这里，WF是一个速度滤波器来净化RI光束。例如，这个系统已经成功地提供了一个^<14 bb0的光束，超过10^6 pps，纯度接近100%。(2)首次成功地研究了高温高密度条件下爆炸氢燃烧发生的最关键的恒星反应之一，^<14>O(α,p)^<17>F，大致证实了先前的理论预测，即该反应是x射线燃烧的开始过程。它位于第一代明星热pp链的突破点。一种新的共振自旋宇称赋值，确定了该能级对高温下天体物理反应的重要性。(4)利用来自CRIB的^<21>Na, ^<22>Mg,^<23>Mg, ^<25>Al和^<26>Si的质子共振束对rp过程的早期阶段进行了一系列质子共振搜索，在所有研究的体系中都发现了新的共振。(5)研究了13N(p, g)14O恒星与13N束流反应中与热- cns循环相关的共振态，非常准确地证实了长时间预测的单粒子态。这种共振会影响高温条件下的反应速率。(6)为核天体物理项目研制了高分辨率磁摄谱仪。一种高分辨率的测量方法已经开发出来，包括回旋加速器，束流线和摄谱仪的调谐，给出约40kev的104mev光束。少

Under the present project, a low-energy RI beam separator, CRIB has been developed, which has been successfully providing a unique opportunity to investigate the stellar reactions under explosive burning that involve unstable nuclei for the first time in Japan. A summary of the accomplishment of the works performed in the present is described below :(1)The low-energy RI beam in-flight separator, CRIB that has a configuration of QMDQDMQ+WF, has been developed mainly for pursuing the present project. Here, WF is a velocity filter to purify the RI beams. This system, for instance, has successfully provided an ^<14>O beam of more than 10^6 pps with nearly 100 % purity.(2)One of the most critical stellar reactions for the onset of the explosive hydrogen burning under high temperature and high-density condition, ^<14>O(α,p)^<17>F, was successfully investigated for the first time, confirming roughly the previous theoretical prediction that this reaction is the onset process for the X-ray burs … More t.(3)Another experiment is a study of proton resonances important for ^<11>C(p,γ)^<12>B, which locates at the breakout point from the hot-pp chain in the first generation stars. A new spin-parity assignment has been made for a resonance, identifying the importance of the level for the astrophysical reaction at high temperatures.(4)A series of proton resonance searches have been made for the early stage of the rp-process with RI beams of ^<21>Na, ^<22>Mg,^<23>Mg, ^<25>Al and ^<26>Si from CRIB, identifying new resonances in all systems studied here.(5)Resonant states, relevant to the hot-CNS cycle, were investigated for the 13N(p, g)14O stellar reaction with a 13N beam, confirming very dearly a single particle state predicted long. This resonance will affect the reaction rate at high temperature condition.(6)A high-resolution magnetic spectrograph has been developed for nuclear astrophysics project. A method of high resolution measurements has been developed including the tuning of the Cyclotron, the beam line and the spectrograph, giving about 40 keV for 104 MeV a-beam.. Less