Sub-threshold states in Ne19 relevant to F18(p,α)O15
Sub-threshold states in Ne19 relevant to F18(p,α)O15
复制标题
Ne19 中与 F18(p,α)O15 相关的亚阈值状态
DOI：
10.1103/physrevc.103.015807
复制
发表时间：
2021
影响因子：
3.1
通讯作者：
et al.
中科院分区：
文献类型：
--
作者：
Riley J. E.、Laird A. M.、de Sereville N.、Suzuki. D;et al.
背景：经典新星是热核爆炸产生的若干射线发射体，是MeV级卫星观测的主要目标。早期射线的发射主要取决于反应速率，尽管有许多实验和理论上的努力，仍然是uncertaints.Purpose：在反应速率的主要不确定性之一是在伽莫夫窗口的贡献，在更高的能量亚thresholdstates和已知的宽态之间的干扰。因此，本工作的目的是阐明这些亚阈态的存在及其性质。方法：在Tandem-ALTO装置上，利用电荷交换反应研究了复合核中的态。用恩格分极光谱仪探测到了Triton，同时用双面硅条探测器阵列收集了来自未束缚态的衰变质子或粒子。结果：在的符合产额为高自旋，支持了它确实是由高自旋和低自旋分量组成的双重态的结论。在6 MeV附近观察到了一个宽的低自旋态的证据。提取了质子阈值以上几种状态的分支比，发现与文献一致。矩阵计算显示了亚阈态对质子阈以上天体物理重要能区的相对贡献.结论：和的能级方案还不够清楚，需要进一步研究模拟分配.在6兆电子伏的暂定广泛的状态可能只发挥作用，如果减少质子的宽度是大的。
Background:Classical novae result from thermonuclear explosions producing several-ray emitters which are prime targets for satellites observing in the MeV range. The early-ray emission depends critically on thereaction rate which, despite many experimental and theoretical efforts, still remains uncertain.Purpose:One of the main uncertainties in thereaction rate is the contribution in the Gamow window of interference between sub-thresholdstates and known broad states at higher energies. Therefore the goal of this work is to clarify the existence and the nature of these sub-threshold states.Methods:States in thecompound nucleus were studied at the Tandem-ALTO facility using thecharge-exchange reaction. Tritons were detected with an Enge Split-pole spectrometer while decaying protons orparticles from unboundstates were collected, in coincidence, with a double-sided silicon strip detector array. Angular correlations were extracted and constraints on the spin and parity of decaying states established.Results:The coincidence yield atwas observed to be high spin, supporting the conclusion that it is indeed a doublet consisting of high-spin and low-spin components. Evidence for a broad, low-spin state was observed around 6 MeV. Branching ratios were extracted for several states above the proton threshold and were found to be consistent with the literature.-matrix calculations show the relative contribution of sub-threshold states to the astrophysically important energy region above the proton threshold.Conclusions:The levels schemes ofandare still not sufficiently well known and further studies of the analog assignments are needed. The tentative broad state at 6 MeV may only play a role if the reduced proton width is large.