权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Nuclear Reaction Mechanisms for Synthesis of Superheavy Elements

超重元素合成的核反应机制

基本信息

批准号：
13640278
负责人：
ABE Yasuhisa
金额：
$ 1.92万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

项目摘要

Experiments of syntheses of the superheavy elements have been made more or less empirically, because there have been no reliable reaction theory for such unstable systems. Nevertheless, we want to synthesize as heavier elements as possible in order to know how many elements exist. According to the experiences, production rates decrease dramatically as the charge number Z of the element increases and thus, machine time is required enormously. Therefore, it is crucial to know optimum conditions for the productions, in other words, precise theoretical predictions of excitation functions for xn reaction channels, which is exactly the purpose of the present project. Now, it is achieved, as is shown in the publications, the list of which is attached below.Most unknown theoretically was mechanisms of the fusion of massive heavy ions which leads to the formation of superheavy compound nuclei. We have employed a Langevin Approach, which was firstly proposed by the head investigator of the prese … More nt project for description of nuclear collective motions, and was found to be successful for fusion of heavy ions and subsequent fission. We have developed the unique theoretical framework, i.e., the two-step model for synthesis of superheavy elements, which is now recognized as a canonical theoretical model, and was presented in the 2nd International Conference on Chemistry and Physics of Transactinide Elements, held at Napa, California, USA, Nov. 16-20, 2003, as an Introductory Review of Nuclear Reaction Theory.Furthermore, we have succeeded in reproducing the available data of the experiments with so-called hot and cold fusion paths. Now, we are making predictions on the elements Z=113 and 114, which are expected to be useful in planning experiments, and at the same time, are waiting for experimental confirmation. A new statistical code has been developed which enables us to follow time evolution of the cooling process of the superheavy compound nuclei. This is now open for potential users. Less

超重元素的合成实验或多或少是凭经验进行的，因为对于这种不稳定的体系还没有可靠的反应理论。然而，我们想要合成尽可能重的元素，以便知道有多少元素存在。根据经验，随着元件装料次数Z的增加，生产率急剧下降，因此需要大量的机器时间。因此，了解生产的最佳条件是至关重要的，换句话说，准确的xn反应通道激发函数的理论预测，这正是本项目的目的。现在，如出版物所示，它已经实现了，列表如下。理论上最未知的是导致超重化合物核形成的大质量重离子聚变的机制。我们采用了朗之万法，这是由Prese…的首席研究员首先提出的。More NT计划用于描述核集体运动，并被发现成功地用于重离子聚变和随后的裂变。我们发展了独特的理论框架，即超重元素合成的两步模型，该模型现已被公认为规范的理论模型，并于2003年11月16-20日在美国加利福尼亚州纳帕举行的第二届国际超文本元素化学和物理会议上发表，作为核反应理论的介绍性综述。此外，我们还成功地再现了所谓的热和冷聚变路径实验的可用数据。现在，我们正在对Z=113和114元素进行预测，这两个元素有望在计划实验中发挥作用，同时正在等待实验证实。发展了一个新的统计程序，使我们能够跟踪超重化合物核冷却过程的时间演化。现在，它对潜在用户开放。较少