Nucleosynthesis in Explosive Hydrogen Burning

(1)研究了^ Ne中4.033 MeV的3/2^+态的性质<19>，它决定了^<15>O（α，γ）^ Ne的反应速率，而^ O（α，γ）^<19>Ne的反应速率决定了新星的产生。通过电荷对称反应^<20>Ne（d，t）和（d，^3He）研究了这个态，得到J^π=3/2^+和S=0.033。用^<20>Ne（^3He，t）反应激发态，用Si探测器测量α衰变，研究了α衰变特性。然而，在本底水平以上没有观察到显著的事件，表明α宽度的上限为100μeV。(2)用<14><14>磁谱仪<17>对^<20>Ne（p，t）^ Ne反应进行了高精度测量，研究了高T rp过程触发反应^O（α，p）^ F的结构<18>。对^ Ne的α阈值附近的态进行了高精度的激发能测定和自旋归属<18>。(3)类似地，<22>通过（p ...更多信息 ，t）反应，导致在质子阈值附近发现了一些新的共振。新的共振将有显着的影响，因为它们是在伽莫夫窗口的范围内的新星。(4)用11.8 MeV的^ C（d，p）^ C直接转移反应成功地检验了渐近归一化（ANC）方法<12><13>。它为我们提供了一个非常低能量的直接中子俘获截面，其不确定度约为8%。这证明ANC方法在± 10%的不确定度范围内适用于直接中子俘获反应。(5)利用大面积硅探测器研制了一种具有较高粒子识别能力的焦平面探测器。(6)为了研究宇宙爆炸条件下的核反应，研制了一种新型的放射性束流分离器和实验探测器。(7)新星模型的计算，包括这里得到的反应速率，进行推断元素丰度生产，并确定关键的反应进行调查的新星问题。少

(1) Investigation of the property of the crucial state, the 4.033 MeV 3/2^+ state in ^<19>Ne, which dominates the reaction rate of ^<15>O(α,γ)^<19>Ne that determines the onset of novae. This state was studied by the charge-symmetry reactions ^<20>Ne(d,t) and (d,^3He), resulting in J^π=3/2^+ and S=0.033. The α-decay property was also studied by exciting the state by the ^<20>Ne(^3He,t) reaction, and measuring the α decay with Si detectors. However, no significant events were observed above the background level, suggesting the upper limit of the α-width to be 100μeV. (2) The structure of ^<14>O which is crucial for the trigger reaction of the high-T rp-process, ^<14>O(α,p)^<17>F, was also investigated by a high-precision measurement of the ^<20>Ne(p,t) ^<18>Ne reaction with a magnetic spectrograph. Excitation energy determination with high precision and spin assignments were made for the states near the α threshold in ^<18>Ne. (3) Similarly, the structure of ^<22>Mg was studied by the (p … More ,t) reaction, resulting in a discovery of some new resonances near the proton threshold. The new resonances will have significant influences as they are in the range of the Gamow window of novae. (4) The asymptotic normalization (ANC) method was successfully tested with using a direct transfer reaction of ^<12>C(d,p)^<13>C at 11.8 MeV. It provided us a very low-energy direct neutron capture cross sections with an uncertainty of about 8 %. This proves that the ANC method is useful for applying to the direct neutron capture reactions within an uncertainty of about ±10 %. (5) A focal plane detector was developed which has a high ability in particle identification using a large-area Si detectors. (6) A new RI-beam separator and the experimental detectors were developed to study the nuclear reactions under explosive conditions in the Universe. (7) Nova model calculations, including the reaction rates obtained here, were performed to deduce the elemental abundance productions and also to identify crucial reactions to be investigated for the nova problem. Less