Nuclear Structure and Reactions: Theory and Experiment

核结构和反应：理论与实验

• 批准号: ST/J000051/1
• 负责人: Philip Malzard Walker
• 金额: $ 279.6万
• 依托单位: University of Surrey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FJ000051%2F1
• 关键词: Nuclear; Structure; Reactions; Theory; Experiment; Nuclear; Structure; Reactions; Theory; Experiment

Nuclear physics research is undergoing a transformation. For a hundred years, atomic nuclei have been probed by collisions between stable beams and stable targets, with just a small number of radioactive isotopes being available. Now, building on steady progress over the past 20 years, it is at last becoming possible to generate intense beams of a wide range of short-lived isotopes, so-called 'radioactive beams'. This enables us vastly to expand the scope of experimental nuclear research. For example, it is now realistic to plan to study in the laboratory a range of nuclear reactions that take place in exploding stars. Thereby, we will be able to understand how the chemical elements that we find on Earth were formed and distributed through the Universe. At the core of our experimental research is our strong participation at leading European radioactive-beam facilities: FAIR at GSI, Darmstadt, Germany; SPIRAL at GANIL, Caen, France; and ISOLDE at CERN, Geneva, Switzerland. While we are now contributing, or planning to contribute, to substantial technical developments at these facilities, the present grant request is focused on the exploitation of the capabilities that are now becoming available. To achieve our physics objectives, we also need to use other facilities, including stable-isotope accelerators, since these can provide complementary capabilities. Experimental progress is intimately linked with theory, where novel and practical approaches are a hallmark of the Surrey group. A key and unique feature (within the UK) of our group is our blend of theoretical and experimental capability. Our science goals are aligned with current STFC strategy for nuclear physics, as expressed in detail through the Nuclear Physics Advisory Panel. We wish to understand the boundaries of nuclear existence, i.e. the limiting conditions that enable neutrons and protons to bind together to form nuclei. Under such conditions, the nuclear system is in a delicate state and shows unusual phenomena. It is very sensitive to the properties of the nuclear force. For example, weakly bound neutrons can orbit their parent nucleus at remarkably large distances. This is already known, and our group made key contributions to this knowledge. What is unknown is whether, and to what extent, the neutrons and protons can show different collective behaviours. Also unknown, for most elements, is how many neutrons can bind to a given number of protons. It is features such as these that determine how stars explode. So, we need a more sophisticated understanding of the nuclear force, and we need experimental information about nuclei with unusual combinations of neutrons and protons to test our theoretical ideas and models. Therefore, theory and experiment go hand-in-hand as we push forward towards the nuclear limits. An overview of nuclear binding reveals that about one half of predicted nuclei have never been observed, and the vast majority of this unknown territory involves nuclei with an excess of neutrons. The focus of our activity addresses this 'neutron-rich' territory, exploiting the new capabilities with radioactive beams. Our principal motivation is the basic science, and we contribute strongly to the world sum of knowledge and understanding. Nevertheless, there are more-tangible benefits. For example, our radiation-detector advances can be incorporated in medical diagnosis and treatment. In addition, we provide an excellent training environment for our research students and staff, many of whom go on to work in the nuclear power industry, helping to fill the current skills gap. On a more adventurous note, our special interest in nuclear isomers (energy traps) could lead to novel energy applications. Furthermore, we have a keen interest in sharing our specialist knowledge with a wide audience, and we already have an enviable track record with the media.

核物理研究正在进行转变。一百年来，通过稳定梁和稳定靶标之间的碰撞来探测原子核，只有少量的放射性同位素可用。现在，在过去20年中，基于稳定的进步，终于有可能产生各种短寿命的同位素，即所谓的“放射性光束”。这使我们大大扩大了实验核研究的范围。例如，现在计划在实验室中研究在爆炸恒星中发生的一系列核反应是现实的。因此，我们将能够理解我们在地球上发现的化学元素是如何通过宇宙形成和分布的。我们实验研究的核心是我们在领先的欧洲放射梁设施中有很大的参与：在德国达姆施塔特的GSI公平；在法国凯恩的甘尼尔螺旋；和瑞士日内瓦塞瓦的伊索尔。尽管我们现在正在为这些设施的实质性技术发展做出贡献或计划做出贡献，但目前的赠款请求集中在利用现在可用的功能上。为了实现我们的物理目标，我们还需要使用其他设施，包括稳定的异位加速器，因为这些设施可以提供互补的功能。实验进步与理论密切相关，理论是新颖和实用的方法是萨里群体的标志。我们小组的一个关键和独特的特征是我们的理论和实验能力融合。我们的科学目标与当前的STFC核物理战略保持一致，如核物理咨询小组详细表达。我们希望了解核存在的边界，即使中子和质子结合在一起形成核的限制条件。在这种情况下，核系统处于微妙的状态，并显示出异常的现象。它对核力量的性质非常敏感。例如，弱结合的中子可以在较大的距离处绕其父核绕。这已经知道，我们的小组为这一知识做出了关键贡献。未知的是中子和质子是否可以显示出不同的集体行为。对于大多数元素而言，也未知的是有多少中子可以与给定数量的质子结合。诸如此类的功能决定了恒星的爆炸方式。因此，我们需要对核力量的更复杂的理解，并且需要与中子和质子的异常组合有关核的实验信息，以测试我们的理论思想和模型。因此，当我们向前迈向核极限时，理论和实验齐头并进。核结合的概述表明，从未观察到大约一半的预测核，而且绝大多数未知的领土涉及中子过多的核。我们活动的重点解决了这一“中子富裕”领域，并用放射性梁利用了新功能。我们的主要动机是基础科学，我们为世界知识和理解的总和做出了巨大贡献。然而，有更多的好处。例如，我们的辐射检测器的进步可以纳入医学诊断和治疗中。此外，我们为研究专业的学生和员工提供了出色的培训环境，其中许多人继续从事核电行业工作，帮助填补了当前的技能差距。更具冒险精神，我们对核异构体（能量陷阱）的特殊兴趣可能导致新颖的能源应用。此外，我们对与广泛的受众分享我们的专业知识有浓厚的兴趣，并且我们已经在媒体上拥有令人羡慕的往绩。