低能核反应及相关核结构研究进展  

Progress on nuclear reactions and related nuclear structure at low energies

作　　者：杨磊[1] 林承键[1] 贾会明[1] 马南茹[1] 温培威 杨峰[1] 张焕乔[1] YANG Lei;LIN Chengjian;JIA Huiming;MA Nanru;WEN Peiwei;YANG Feng;ZHANG Huanqiao(China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国原子能科学研究院,北京102413

出　　处：《核技术》2023年第8期63-73,共11页Nuclear Techniques

基　　金：国家重点研发计划项目(No.2022YFA1602302);国家自然科学基金(No.U2167204,No.12175314,No.12235020);中核集团领创项目(No.LC202309000201)。

摘　　要：中国原子能科学研究院核反应团队依托国内外的大科学装置,在重离子熔合-裂变机制、垒下熔合增强机制、奇特核反应机制、奇异结构和奇异衰变方面取得了多项原创性成果。本文对其中的代表性成果进行了简要回顾。主要包括:(1)系统调查了正Q值中子转移的耦合道效应,并提出了自洽的方法评估转移耦合的贡献,发现了异常的同位素效应;(2)提出了用高精度背角准弹散射方法抽取原子核的形变参数,确证了原子核存在十六极形变;(3)提出了用轻带电粒子的替代俘获反应方法,基于此方法给出了关键的^(239)Pu(n,2n)反应截面;(4)系统考察了sd壳丰质子核奇异衰变谱学,发现了^(22)Si的β缓发双质子衰变模式,并发现镜像核^(22)Si/^(22)O的β衰变中存在极大的同位旋不对称性,同时在^(26)Si中发现了迄今为止最强的同位旋混合态;(5)系统研究了奇特核体系在近垒能区的反应机制,首次给出了实验证据表明经典色散关系不适用于中子晕核^(6)He+^(209)Bi体系,并对质子滴线核8B和17F的反应机制进行了细致考察。本文也对将来基于重离子飞行时间谱仪和北京放射性束流线可能开展的工作进行了展望。Through the use of the accelerator facilities at home and abroad,the nuclear reaction group of the China Institute of Atomic Energy has made many remarkable achievements in the study of fusion-fission dynamics,fusionenhancement mechanisms at sub-barrier energies,reaction dynamics induced by exotic nuclei,and the related exotic nuclear structure and proton decay.In this study,some representative achievements are reviewed briefly.(1)The fusion mechanisms at near-barrier energies were investigated systematically,and a self-consistent method to evaluate the coupled-channel effects was proposed.(2)Nuclear deformation parameters were extracted from backward quasielastic scattering,which offered evidence for hexadecapole shapes.(3)A surrogate capture method was developed,based on which the first ^(239)Pu(n,2n)excitation function developed in China was derived.(4)Systematic studies of exotic decay spectroscopies for proton-rich nuclei in the sd-shell were performed,following which aβ2p decay of 22Si and a large isospin-asymmetry decay were discovered,and a strongly isospin-mixed doublet in ^(26)Si was revealed.(5)Systematic studies of reaction mechanisms induced by exotic nuclei at energies close to the Coulomb barrier were performed,providing evidence for the failure of the dispersion relation in the optical potential of ^(6)He+^(209)Bi,and the reaction dynamics of proton drip-line nuclei of 8B and 17F were investigated.Future research based on the new HiTOF and BRIF facilities is discussed as well.

关 键 词：重离子核反应 近垒能区 奇异核结构 

分 类 号：TL99[核科学技术—核技术及应用]