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

我们研究了各种主题，讨论了从fluctuation-dissipation dynamics的视点中产生的大量核反应。（1）我们已经研究了用3-dimensional Langevin equation在融合中的大规模核核聚变现象。We have estimated the incident energy necessary for fusion forイD1100イD1Mo+イD1100イD1Mo，イD1100イD1Mo+イD1110イD1Pd， andイD1110イD1Pd+イD1110イD1Pd。由于使用了统计级联代码，我们已经估计了这些系统的蒸发安置交叉部分，并将它们与实验进行了比较。（2）我们已经研究了用3个维度的不同动力学模型来处理大不对称事件通道的超重元素合成的动力学。在1999年，有一个新的实验的超重元素的合成。In particular， the results of the yeD 148 yeD 1Ca + yeD 1244 yeD 1 Pu reaction that was performed at Flerov Laboratory in Dubua， Russia与我们的理论预测达成了良好的协议。在美国劳伦斯伯克利实验室进行了实验，以处理低激发能量实验，我们已经通过将外壳校正的能量纳入对聚变阶段的能量和水平密度参数的激发能量依赖性来改进我们的计算，该实验是从外壳校正产生的。（3）为了研究蒸发安置交叉部分的系统，并预测超重元素合成的最佳条件，我们已经参数化了动态计算的结果作为事件能量、质量对称、原子和复合系统的函数。（4）我们已经利用了Fokker-Planck equation的平均第一次通行时间，以便在情况下计算飞行器的飞行器宽度非常低。我们在级联代码中引入了这一方法，并在低功耗屏障的情况下估计了可生存性的可能性。

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.