弱束缚原子核破裂反应机制研究  

Study on the Breakup Mechanism of Weakly Bound Nuclei

作　　者：吴艳松 张高龙[1] 张广鑫 林承键[3] 杨磊[3] 吕昊博 焦振威 王明李 WU Yansong;ZHANG Gaolong;ZHANG Guangxin;LIN Chengjian;YANG Lei;LÜHaobo;JIAO Zhenwei;WANG Mingli(School of Physics,BeiHang University,Beijing 102206,China;Sino-French Institute of Nuclear Engineering and Technology,Sun Yat-Sen University,Zhuhai 519082,Guangdong,China;China Institute of Auomic Energy,Beijing 102413,China)

机构地区：[1]北京航空航天大学物理学院,北京100191 [2]中山大学中法核工程与技术学院,广东珠海519082 [3]中国原子能科学研究院,北京102413

出　　处：《原子核物理评论》2024年第1期352-359,共8页Nuclear Physics Review

基　　金：国家自然科学基金资助项目(U2167204,11975040)。

摘　　要：近库仑势垒附近发生的核反应是研究核结构与反应动力学相互作用的一个有效途径。随着加速器的发展,越来越多的奇特核可以被产生,因此进一步去理解弱束缚能对于反应动力学和熔合反应的影响是至关重要的。目前大量的实验表明,^(6,7)Li和^(9)Be等稳定弱束缚核与重质量靶核的完全熔合截面与已有的理论模型计算的熔合截面以及紧束缚核体系推导出的熔合截面相比要低30%左右。为了探究弱束缚核的破裂对完全熔合截面压低的作用,研究弱束缚核的破裂效应与破裂机制便成为人们一个新的关注区域。目前国内外课题组利用符合测量方法针对弱束缚核破裂反应开展了部分研究,认为弱束缚核垒上完全熔合截面压低主要来源于转移反应后生成的类弹核发生瞬时破裂导致的,并给出了不同破裂反应道对于完全熔合压低现象的相对贡献。本课题组基于大立体角覆盖阵列也开展了^(6,7)Li+^(209)Bi破裂机制研究的相关实验,束流能量为30、40、47 MeV,成功鉴别了α+α、α+t、α+d、α+p破裂道的瞬时破裂和共振破裂成分,并在^(6)Li+^(209)Bi实验数据中首次观测到了α+t破裂道,进一步完善了^(6,7)Li+^(209)Bi破裂反应机制。The nuclear reaction at energies near the Coulomb barrier is an effective way to study the interaction between nuclear structure and dynamics.As more exotic weakly bound nuclei become accessible at new accelerator facilities,it is becoming critically important to understand the influence of weak binding energy on reaction dynamics,including on fusion.At present,a large number of experiments have shown that the complete fusion cross section between stable weakly bound nuclei such as^(6,7)Li+^(9)Be and heavy mass target nuclei is suppressed about 30%lower than the fusion cross section calculated by existing theoretical models and the fusion cross-section derived from tightly bound nuclear systems.In order to investigate the breakup effect of weakly bound nuclei on the suppression of the complete fusion cross section,studying the breakup reaction and mechanism of weakly bound nuclei has become concerned.Currently,research groups both domestically and internationally have conducted studies on the breakup reactions of weakly bound nuclei by coincidence measurement.It is concluded that the suppression of the above-barrier complete fusion cross section of the weakly bound nuclei is mainly caused by the prompt breakup of the projectile-like nuclei formed through the transfer of the weakly bound nuclei,and the relative contributions of different breakup channels to the suppression of the complete fusion were obtained.Our research group has also conducted experiments on the breakup mechanism of^(6,7)Li+^(209)Bibased on a large solid-angle coverage array.The beam energies were set at 30,40,and 47 MeV.We successfully identified the components of prompt breakup and resonant breakup for theα+α,α+t,α+d,andα+p breakup channels.For the first time in the 6Li+209Bi experimental data,theα+t break-up channel was observed,further refining the understanding of the break-up reaction mechanism for^(6,7)Li+^(209)Bi.

关 键 词：弱束缚核 完全熔合截面 压低因子 破裂反应 

分 类 号：O571.53[理学—粒子物理与原子核物理]