基于双核模型研究大质量转移反应中结团发射机制  

Cluster emission in massive transfer reactions based on dinuclear system model

作　　者：徐思宇 冯兆庆 XU Siyu;FENG Zhaoqing(School of Physics and Optoelectronics,South China University of Technology,Guangzhou 510641,China)

机构地区：[1]华南理工大学、物理与光电学院,广州510641

出　　处：《核技术》2023年第3期67-75,共9页Nuclear Techniques

基　　金：国家自然科学基金(No.12175072、No.11722546);华南理工大学双一流建设经费(No.20210115)资助。

摘　　要：本文借助双核模型,进行了对多核子转移反应中前平衡结团发射机制进行了系统研究。以反应系统^(12)C+^(209)Bi、^(40)Ca+^(208)Pb和^(48)Ca+^(238)U为例,重点分析了库仑位垒附近重离子碰撞产生前平衡轻粒子,如中子、质子、氘核、氚核、^(3)He、^(4)He、^(6)Li、^(7)Li、^(8)Be和^(9)Be时间演化、动能分布和角分布。研究结果表明:结团发射呈现出一定核结构效应,^(4)He发射概率与质子相当并远大于^(3)He。前平衡结团主要分布在“类弹”和“类靶”角度区域发射,其动能分布呈现出玻尔兹曼分布形式。考虑结团预形成因子后该方法可以拓展用于不稳定原子核引起的结团发射机制研究。[Background]The pre-equilibrium cluster manifests the nuclear structure and reaction dynamics of collision system.The systematical investigation of cluster emission in transfer reactions is of significance in deep understanding of the synthesis of superheavy nuclei,shell evolution,new isotope production,etc.[Purpose]The dynamics of pre-equilibrium cluster in a few of nucleon transfer reaction has been described by theoretical model,such as exciton model,cluster model.However,the cluster emission in massive transfer is very complicated because of the emission mechanism associated with the structure properties and also the dynamical process.[Methods]In this work,the pre-equilibrium cluster emission in massive transfer reaction has been systematically investigated within the dinuclear system model.The model has been successfully used for describing the massive fusion reaction and multi-nucleon transfer dynamics.The nucleon exchange and energy dissipation take place once the dinuclear system is formed.The nucleon transfer between the binary fragments is governed by the single-particle Hamiltonian and proceeds around the Fermi surface formed by the dinuclear system.The master equation is used for the nucleon transfer dynamics and the relative motion energy dissipation is taken into account.The dynamics of neutron,proton,deuteron,triton,^(3)He,^(4)He,^(6,7)Li and ^(8,9)Be in collisions of ^(12)C+^(209)Bi,^(40)Ca+^(208)Pb and ^(48)Ca+^(238)U near Coulomb barrier energies is analyzed,i.e.,temporal evolution of production rate,kinetic energy spectra and angular distribution.[Results]It is found that the emission probability of ^(4)He is the same magnitude of proton emission and several orders larger than the one of ^(3)He.Both the nuclear structure and dynamical effects influence the pre-equilibrium cluster production.[Conclusions]The pre-equilibrium clusters are emitted from the'projectile-like'and'target-like'fragments and the angular distributions manifest the similar trends.The kinetic energy spectra of clusters are s

关 键 词：结团发射 前平衡过程 转移反应 双核模型 

分 类 号：TL99[核科学技术—核技术及应用]