DISSIPATIVE DYNAMICS OF HEAVY-ION FUSION-FISSION REACTION

重离子聚变裂变反应的耗散动力学

• 批准号: 08640398
• 负责人: WADA Takahiro
• 金额: $ 1.41万
• 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: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08640398/
• 关键词: Highly Excited Compound Nucleus; Fusion-Fission Reaction; Dissipative Dynamics; Multi-Dimensional Langevin Equation; Nuclear Friction; Particle Multiplicity; Fusion Hindrance; Superheavy Element; Fusion Hindrace; fast fission; 分裂片分布

We have studied various subjects concerning the heavy-ion fusion-fission reaction from the viewpoint of dissipative dynamics.(1) We have developed a computer code for solving a multi-dimensional Langevin equation. We have improved the interpolation routine to obtain a good performance especially on super computers. We can solve 3- and 4- dimensional Langevin equation without difficulties.(2) We have analyzed the experimental data on the angular momentum dependence of prescission time obtained from the coincidence measurements of gamma-ray and charged particles. We have reproduced the experimentally deduced prescission time, including its angular momentum dependence.(3) We have analyzed the phenomenon of fusion hindrance using the 2- and 3-dimensional Langevin equation. We have reproduced the experimental data for symmetric-like systems, and also calculated the systems with large mass asymmetry.(4) We have studied the dynamical process of the synthesis of superheavy elements by dissipative dynamical models. First, we used the 1-dimensional Smoluchowski equation. Then, for a more realistic estimation, we proposed to divide the process in two stages and used 2-dimensional Langevin equation and 2-dimensional Smoluchowski equation for respective stages. We have predicted that the maximum yield is obtained around E^<**>=25MeV.(5) We have analyzed the new data on the fission lifetime obtained with the crystal blocking method. We used the statistical model and the dissiative dynamical model.(6) We have studied the fission of excited nuclei using the microscopic nuclear friction coefficient calculated by Dr. Yamaji, RIKEN.

我们从耗散动力学的观点研究了重离子聚变-裂变反应的各种问题。(1)我们已经开发了一个计算机代码解决多维朗之万方程。我们改进了插值程序，以获得良好的性能，特别是在超级计算机上。我们可以毫无困难地求解三维和四维朗之万方程。(2)本文分析了γ射线和带电粒子的符合测量中角动量与裂前时间关系的实验数据。我们重现了实验推导的precission时间，包括它的角动量依赖性。(3)我们用二维和三维朗之万方程分析了熔合位阻现象。我们再现了类抛物系统的实验数据，并计算了具有大质量不对称性的系统。(4)我们用耗散动力学模型研究了超重元素合成的动力学过程。首先，我们使用一维Smoluchowski方程。然后，为了更真实地估计，我们提出了将该过程分为两个阶段，并分别使用二维Langevin方程和二维Smoluchowski方程。我们预测在E^<**>= 25 MeV附近获得最大产额。(5)我们分析了用晶体阻塞法获得的裂变寿命的新数据。我们使用的统计模型和耗散动力学模型。(6)本文用Yamaji博士计算的微观核摩擦系数研究了激发核的裂变。

项目成果

K.Okazaki: "Simulation for Fusion and Fusion-Fission Dynamics in Heavy Nuclei" Proc.3rd Tours Symp.on Nuclear Physics,AIP Conference Proceedings. (印刷中). (1998)

K.Okazaki：“重核聚变和聚变裂变动力学的模拟”Proc.3rd Tours Symp.on 核物理，AIP 会议记录（1998 年）。

T.Wada: "Fusion as Dissipative Process" Proc. 2nd Japan-Italy Symp., World Scientific, Singapore. 77-87 (1996)

T.Wada：“聚变作为耗散过程”Proc。

Y.Aritomo: "Dynamics of the Superheavy Element Synthesis with a Diffusion Model" Proc.3rd Tours Symp.on Nuclear Physics,AIP Conference Proceedings. (印刷中). (1998)

Y.Aritomo：“采用扩散模型的超重元素合成动力学”Proc.3rd Tours Symp.on 核物理，AIP 会议论文集（1998 年出版）。

Y. Aritomo: "A Diffusion Mechanism for Synthesis of Superheavy Elements" Physical Review. C55・3. R1011-R1014 (1997)

Y. Aritomo：“超重元素合成的扩散机制”物理评论 C55·3（1997）。

Yasuhisa Abe: "On Stochastic Approaches of Nuclear Dynamics" Physics Reports. 275・2,3. 49-196 (1996)

安倍泰久：“核动力学的随机方法”物理报告275・2,3（1996）。