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FLUCUATION-DISSIPATION DYNAMICS IN THE FUSION-FISSION REACTION OF MASSIVE NUCLEI

大质量核聚变裂变反应中的涨落耗散动力学

基本信息

批准号：
10640287
负责人：
WADA Takahiro
金额：
$ 2.11万
依托单位：
KONAN UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640287/
关键词：
Fusion-Fission Reaction Fluctuation-Dissipation Dynamics Multi-Dimensional Langevin Equation Mass Asymmetry Nuclear Friction Fusion Hindrance Superheavy Elements Evaporation Residue Cross Section 高励起複合核 Fusion hindrance

项目摘要

We have studied various subjects concerning the fusion-fission reaction of massive nuclei from the viewpoint of fluctuation-dissipation dynamics.(1) We have studied the phenomenon of fusion hindrance in the fusion of massive nuclei with the 3-dimensional Langevin equation. We have estimated the incident energy necessary for fusion for ィイD1100ィエD1Mo+ィイD1100ィエD1Mo, ィイD1100ィエD1Mo+ィイD1110ィエD1Pd, and ィイD1110ィエD1Pd+ィイD1110ィエD1Pd systems. By using the statistical cascade code, we have estimated the evaporation residue cross section for these systems and compared them with the experiments.(2) We have studied the dynamics of the synthesis of superheavy elements with the 3-dimesional dissipative dynamical model to treat the mass-asymmetric incident channels. In 1999, there performed new experiments of the synthesis of the superheavy elements. In particular, the results of the ィイD148ィエD1Ca+ィイD1244ィエD1Pu reaction that was performed at Flerov Laboratory in Dubua, Russia is in good agreement with our theoretical prediction. In order to treat the low excitation energy experiment that was performed at Lawrence Berkeley Laboratory, USA, we have improved our calculation by taking into account of the shell correction energy from the fusion stage and the excitation energy dependence of the level density parameter that is originated from the shell correction.(3) To study systematics of the evaporation residue cross section and to predict the optimum condition for the synthesis of superheavy elements, we have parametrized the results of the dynamical calculation as functions of the incident energy, mass asymmetry, atomic and mass numbers of compound system.(4) We have utilized the mean first passage time of the Fokker-Planck equation to calculate the fission width in the case where the fission barrier is very low. We have incorporated this method in the cascade code and have estimated the survival probability against fission decay in the case of low fission barrier.

我们从涨落-耗散动力学的观点研究了有关大质量核聚变-裂变反应的各种问题。(1)本文用三维朗之万方程研究了大质量核熔合中的熔合阻碍现象。我们估算了三个系统聚变所需的入射能量，其中包括D1100-D1 Mo + D1100-D1 Mo，D1100-D1 Mo + D1110-D1 Pd，D1110-D1 Pd + D1110-D1 Pd。用统计级联程序估算了这些体系的蒸发残馀截面，并与实验结果进行了比较。(2)本文用三维耗散动力学模型处理质量非对称入射通道，研究了超重元素合成的动力学。1999年，进行了新的超重元素合成实验。特别是，在俄罗斯杜布阿的弗莱罗夫实验室进行的氘代D148氘代D1Ca+氘代D1244氘代D1 Pu反应的结果与我们的理论预测吻合得很好。为了处理在美国劳伦斯伯克利实验室进行的低激发能实验，我们改进了我们的计算，考虑到壳层修正能量的融合阶段和激发能的能级密度参数，源于壳层修正。(3)为了研究蒸发残渣截面的系统学和预测合成超重元素的最佳条件，我们将动力学计算结果参数化为入射能量、质量不对称性、化合物体系的原子数和质量数的函数。(4)我们利用Fokker-Planck方程的平均第一通过时间计算了裂变势垒很低时的裂变宽度。我们已将此方法应用于级联程序中，并估算了低裂变势垒情况下裂变衰变的存活概率。