Theoretical study of the scattering of unstable nuclei and the synthesis of superheavy elements

不稳定核散射与超重元素合成的理论研究

基本信息

批准号：
04640280
负责人：
TAKIGAWA Noboru
金额：
$ 1.02万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

This research project aimed at exploring characteristics of heavy-ion collisions induced by unstable nuclei, especially by halo nuclei, and at finding a new way to synthesize superheavy elements. The structure of unstable nuclei and quantum tunneling in multi-dimensional systems were also studied as closely related subjects. The main achievements are as follows. 1. We studied the effect of projectile berak-up on the heavy-ion fusion reactions induced by a halo nucleus, and showed that one can still expect a larger fusion cross section for a halo nucleus than for the other isotopes at energies below the Coulomb barrier, though the projectile break-up moderates the large enhancement of the fusion cross section suggested in one of our previous papers for the collisions of a halo nucleus. 2. We showed that the differential cross section of the elastic scattering in medium energy heavy-ion collisions has a steeper fall off at angles where the so called far-side component dominates if a halo nucleus is used as the projectile. 3. We studied multi-nucleon transfer neactions in deep inelastic heavy-ion collisions based on a transport theory, and found that much larger number of neutrons are exchanged than protons if a halo nucleus is used as the projectile. 4. We showed that the tranverse momentum distribution of the projectile fragments in medium energy heavy-ion collisions gets narrower by reflectiong the reaction mechanism. 5. We studied the effects of environments on the tunneling rate of a macroscoic variable, and showed the importahce of a mass renormalization in the cases, where the environments have slightly shorter time scale than that of the tunneling process. Also, we developed a method, the method of dynamical norm factor, to treat non adiabatic effects in macroscopic quantum tunneling, and demonstrated its numerical accuracy by a few model calculations. Using this method, we analyzed the fission of ^<234>U, and showed that the coupling to a nuclear intrins

该研究项目旨在探索不稳定核，特别是晕核引起的重离子碰撞特性，并寻找合成超重元素的新方法。不稳定核的结构和多维系统中的量子隧道效应也作为密切相关的学科进行了研究。主要成果如下。 1. 我们研究了射弹爆炸对晕核引起的重离子聚变反应的影响，结果表明，在低于库仑的能量下，晕核仍然可以预期比其他同位素有更大的聚变截面障碍，尽管射弹破碎缓和了我们之前一篇关于晕核碰撞的论文中提出的聚变截面的大幅增强。 2.我们表明，如果使用晕核作为射弹，中能重离子碰撞中弹性散射的微分截面在所谓的远侧分量占主导地位的角度处具有更陡的下降。 3. 基于输运理论研究了深部非弹性重离子碰撞中的多核子传递反应，发现如果使用晕核作为弹丸，交换的中子数量远多于质子。 4.通过反映反应机理，我们发现中能重离子碰撞中弹片的横向动量分布变窄。 5. 我们研究了环境对宏观变量的隧道速率的影响，并表明了在环境的时间尺度比隧道过程的时间尺度稍短的情况下质量重正化的重要性。此外，我们还开发了一种方法，即动态范数因子方法，来处理宏观量子隧道中的非绝热效应，并通过一些模型计算证明了其数值准确性。使用这种方法，我们分析了 ^<234>U 的裂变，并表明与核内含子的偶联