Neutron-capture rates for explosive nucleosynthesis: the case of 68Ni(n, γ)69Ni
Neutron-capture rates for explosive nucleosynthesis: the case of 68Ni(n, γ)69Ni
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爆炸性核合成的中子俘获率：以 68Ni(n, γ)69Ni 为例
DOI：
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
R. Surman
中科院分区：
文献类型：
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作者：
A. Spyrou;A. Larsen;S. Liddick;F. Naqvi;B. Crider;A. Dombos;M. Guttormsen;D. Bleuel;A. Couture;L. C. Campo;R. Lewis;S. Mosby;M. Mumpower;G. Perdikakis;C. Prokop;S. J. Quinn;T. Renstrøm;S. Siem;R. Surman
中子俘获反应在重元素核合成中起着重要的作用，因为它们是产生绝大多数重元素的两个过程的驱动力。当中子俘获发生在短寿命的原子核上时，直接研究反应极具挑战性，因此使用间接技术至关重要。目前的工作报告这样一个间接的测量，提供了强有力的约束$^{68}$Ni（n，$\gamma$）$^{69}$Ni反应速率。这是通过填充复合核$^{69}$Ni通过$^{69}$Co的$\beta$衰变和测量$^{69}$Ni中激发态的$\gamma$-射线去激发来完成的。用$\beta$-奥斯陆方法提取了$\gamma$射线强度函数和核能级密度。此外，提取了$^{69}$Co的半衰期，发现与以前的文献值一致。在此之前，$^{68}$Ni（n，$\gamma$）$^{69}$Ni反应是不受约束的，纯理论反应速率是高度不确定的。基于本实验的反应速率的新不确定度（上限和下限之间的变化）约为3倍。常用的反应库JINA-REACLIB和BRUSLIB与实验速率比较吻合。弱$R$-过程计算的新速率的影响进行了讨论。
Neutron-capture reactions play an important role in heavy element nucleosynthesis, since they are the driving force for the two processes that create the vast majority of the heavy elements. When a neutron capture occurs on a short-lived nucleus, it is extremely challenging to study the reaction directly and therefore the use of indirect techniques is essential. The present work reports on such an indirect measurement that provides strong constraints on the $^{68}$Ni(n,$\gamma$)$^{69}$Ni reaction rate. This is done by populating the compound nucleus $^{69}$Ni via the $\beta$ decay of $^{69}$Co and measuring the $\gamma$-ray deexcitation of excited states in $^{69}$Ni. The $\beta$-Oslo method was used to extract the $\gamma$-ray strength function and the nuclear level density. In addition the half-life of $^{69}$Co was extracted and found to be in agreement with previous literature values. Before the present results, the $^{68}$Ni(n,$\gamma$)$^{69}$Ni reaction was unconstrained and the purely theoretical reaction rate was highly uncertain. The new uncertainty on the reaction rate based on the present experiment (variation between upper and lower limit) is approximately a factor of 3. The commonly used reaction libraries JINA-REACLIB and BRUSLIB are in relatively good agreement with the experimental rate. The impact of the new rate on weak $r$-process calculations is discussed.
影响因子：
8.6
作者：
G. Martínez-Pinedo;T. Fischer;A. Lohs;L. Huther
通讯作者：
G. Martínez-Pinedo;T. Fischer;A. Lohs;L. Huther
影响因子：
4.8
作者：
Just, O.;Bauswein, A.;Janka, H-T
通讯作者：
Janka, H-T