Large Decay Rate Variation of ^7Be in Pd and Au

Platinum and gold have the similar crystal structure but different electronic affinities, as well as different effective electron densities near the implanted ions. Both the differences favour larger decay rate of ^7 Be in Pd than that in Au. We measured the variation of the decay rate of ^7Be implanted in Pd and Au host materials. We have found that the decay rate of ^7 Be in Pd is larger than that in Au by 0.8%.     

高能重离子碰撞中的反常子

高能重离子碰撞通常用旁观体-反应区模型来近似地描述,如图1所示.炮弹和靶核两者相互瞄准的部分形成反应区,其以外的部分在碰撞过程中只经受相对轻微的相互作用,可分别看作是炮弹的和靶核的旁观体.通过炮弹和靶核中心并沿入射束流方向的两条平行线间的距离称为瞄准距离或碰撞参     

低能带电粒子聚变反应中的静电屏蔽效应

系统地评述了天体物理感兴趣能区带电粒子核反应中电子屏蔽效应的实验及理论研究的进展 ,简要地介绍了恒星热核反应中等离子体静电屏蔽效应理论探讨的概况 .着重说明深入研究天体物理环境对核过程的影响是核天体物理学的重要课题之一.     

重离子碰撞的反常大横动量和核内的夸克分布

本文分析了800MeV/A ¹²C+¹²C 碰撞中观察到的反常大横动量, 指出它可以自然地解释为核内存在多夸克系统. 根据这一图象作的初步计算和实验符合得很好, 从而从另一侧面印证了由轻子深度非弹中的EMC效应所得到的结论.     

Neutron Spectroscopic Factors of ^7Li and Astrophysical ^6Li（n,γ）^7Li Reaction Rates

Angular distributions of the ^7Li（^6Li, ^6Li）^7Li elastic scattering and the ^7Li（^6Li, ^7Lig.s.）^6Li, ^7Li（^6Li, ^7Li0.48）^6Li transfer reactions at Ec.m. = 23.7 MeV are measured with the Q3D magnetic spectrograph. The optical potential of ^6Li ＋ ^7Li is obtained by fitting the elastic scattering differential cross sections. Based on the distorted wave Born approximation （DWBA） analysis, spectroscopic factors of ^7Li =^6Li n are determined to be 0.73 ± 0.05 and 0.90 ± 0.09 for the ground and first exited states in ^7Li, respectively. Using the spectroscopic factors, the cross sections of the ^6 Li（n, γ0,1）^7 Li direct neutron capture reactions and the astrophysical ^6Li（n, γ）^7 Li reaction rates are derived.     

用长气体靶研究22Na+α共振散射

在日本东京大学CRIB 次级束装置上,用长气体靶开展了22Na+ α共振散射的厚靶实验研究。针对长气体靶实验中的两体运动学重构问题,提出了一套包括构建空间复杂几何关系、计算能量损失以及反应运动学的逐事件分析方法;对22Na+α共振散射的实验数据进行了重构分析,得到了E_c.m. = 4.2 ~ 5.4 MeV 区间22Na( α,α ) 的激发函数,从实验的激发函数中观测到了复合核26Al 5 个较为明显的共振峰。鉴于26Al 共振态的衰变模式比较复杂,本工作发现的26Al新共振态的能级性质有待进一步的理论分析。The 22Na+α resonant scattering is studied via a conventional thick target inverse kinematic method with an extended gas target. A data analysis method is proposed for the two-body reaction kinematic reconstruction, in which the spatial geometry, the reaction kinematics and the energy losses are considered. The experimental data of 22Na+ αresonant scattering have been thus reconstructed, and the excitation function is obtained in the energy interval of Ec.m. =4.2~5.4 MeV. Five resonant states in 26Al are observed in the experimental excitation function. Since several decay modes coexist for the observed 26Al resonant states, multi-channel theoretical analysis is thus needed to reveal their structure and decay features.     

串列加速器放射性次级束流线上的核天体物理反应研究

通过在串列加速器次级束流线上开展反应等的研究,导出天体物理S因子;通过反应的研究,探索核的内部结构.初步得出反应的渐进归一化常数平方为3.5±1.5,表明直接反应的贡献不可忽略.     

Measurement of Angular Distribution for the ^8Li（p,d）^7Li Reaction

The ^8Li（p, d）^7 Li reaction plays an important role in the inhomogeneous Big Bang nucleosynthesis and in the seed-nuclide production phase for the r-process. For the first time, its angular distribution at backward angles was measured in inverse kinematics at Ec.m.=4.0 MeV by using an ^8Li secondary beam. The result of measurement includes the contributions of ^8Li（p, d0）^7Li and ^8Li（p, d1）^7Li^＊. The ^8Li（p, d0）^7Li component is estimated to be 40%-58% in the mixture angular distribution by analysing the measured result.     

弹性共振散射反应的厚靶实验设计

为了开展次级束引起的弹性共振散射反应的厚靶实验, 在北京HI-13串列加速器的次级放射性核束装置上建立了一套包含飞行时间和大面积双面硅微条探测器的探测系统, 并用57.0MeV ¹⁷F次级束轰击7.66mg/cm²的(CH₂)_n靶对¹⁷F+p弹性共振散射反应进行了试测量.     

27P基态晕结构和激发态质子宽度的研究

首先利用扭曲波波恩近似(DWBA)分析了²⁶Mg(d,p)²⁷Mg反应布居²⁷Mg基态、第一和第二激发态的角分布, 导出了²⁷Mg前3个态的渐进归一化系数(ANC). 然后根据镜像核的电荷对称性得出了²⁷P基态的核谱因子和ANC, 以及第一、第二激发态的质子宽度. 基于²⁷P基态的核谱因子和ANC导出了其价质子的均方根半径, 验证了²⁷P基态具有单质子晕结构.