论文标题
130SN束的基态和异构体状态的中子转移反应
Neutron transfer reactions on the ground state and isomeric state of a 130Sn beam
论文作者
论文摘要
由于Z = 50和n = 82壳闭合和R过程核合成路径,围绕中子核132SN的核的结构尤其引起人们的关注。先前已经通过(d,p)反应研究了具有强烈的单粒子样分量的131SN中的四个状态,并以有限的激发能分辨率进行了研究。 130SN(9BE,8BE)131SN和130SN(13C,12C)131SN单中性转移反应在荷利菲尔德放射性离子光束设施中使用粒子γ的一致镜头进行了反向运动学。使用伽玛射线的能量,单粒子样状态能量的不确定性降低了。先前的暂定JPI值已得到证实。在130SN束的异构体成分上转移后,已经观察到了131SN中高旋转状态的衰减。改善的能量和确认对R过程重要的P波状态的自旋差异导致直接相邻的横截面,以在30 KEV处的130SN的基态捕获中子捕获,这与先前的分析一致。对中子转移对异构体的影响的类似评估将需要重要的核结构和反应理论输入。在异构体上转移反应的测量很少,这是132SN区域中的异构体上的第一个。
The structure of nuclei around the neutron-rich nucleus 132Sn is of particular interest due to the vicinity of the Z = 50 and N = 82 shell closures and the r-process nucleosynthetic path. Four states in 131Sn with a strong single-particle-like component have previously been studied via the (d,p) reaction, with limited excitation energy resolution. The 130Sn(9Be,8Be)131Sn and 130Sn(13C,12C)131Sn single-neutron transfer reactions were performed in inverse kinematics at the Holifield Radioactive Ion Beam Facility using particle-gamma coincidence spectroscopy. The uncertainties in the energies of the single-particle-like states have been reduced by more than an order of magnitude using the energies of gamma rays. The previous tentative Jpi values have been confirmed. Decays from high-spin states in 131Sn have been observed following transfer on the isomeric component of the 130Sn beam. The improved energies and confirmed spin-parities of the p-wave states important to the r-process lead to direct-semidirect cross-sections for neutron capture on the ground state of 130Sn at 30 keV that are in agreement with previous analyses. A similar assessment of the impact of neutron-transfer on the isomer would require significant nuclear structure and reaction theory input. There are few measurements of transfer reaction on isomers, and this is the first on an isomer in the 132Sn region.