Nuclear structure and reactions: theory and experiment

核物理研究正处于一个新时代的黎明。近一百年来，原子核一直是通过稳定的束流和稳定的目标之间的碰撞来探测的，只有少量的放射性同位素可用。在过去的20年里，放射性同位素束的发展取得了稳步进展。现在，产生各种短寿命同位素的强流束流，即所谓的“放射性束流”成为可能，从而极大地扩大了实验核研究的范围。例如，在实验室里研究恒星爆炸中发生的一系列核反应是可能的。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形成和分布在宇宙中的。作为其实验研究的核心，萨里小组正在大力参与开发两个欧洲放射束设施：德国达姆施塔特的GSI的FIRE和法国卡昂的GANIL的螺旋。虽然我们正在为这些设施的重大技术发展作出贡献，但目前的赠款申请侧重于利用已经可用的能力。为了实现我们的物理目标，我们还需要使用几种不同的设施，包括稳定同位素加速器，因为这些设施可以提供互补的能力。实验进展与理论密切相关，在理论中，新颖和实用的方法是萨里小组的标志。在世界范围内核物理的发展过程中，理论、实验和辐射探测技术之间有着密切的联系。萨里集团的一个关键特征是我们在这三个领域的实力，这在英国是独一无二的。我们的科学目标与当前的STFC核物理战略保持一致。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原子核的极限条件。在这种情况下，核系统处于微妙状态，出现异常现象。它对核力的性质非常敏感。例如，弱结合的中子可以在非常远的距离绕其母核运行。这一点是已知的，萨里小组对这一知识做出了关键贡献。尚不清楚的是，中子和质子是否以及在多大程度上可以表现出不同的集体行为。对于大多数元素来说，同样未知的是，有多少中子可以与给定数量的质子结合。我们需要对核力有更深入的了解，这需要关于这些微妙原子核的实验信息来检验我们的理论想法和模型。我们还需要更好的辐射探测器(更灵敏、更高效)，以最大限度地利用新的放射性光束。因此，理论、实验和探测器的发展在我们迈向核极限的过程中齐头并进。我们的主要动力是基础科学，我们为世界贡献知识和理解的总和。然而，还有更多实实在在的好处。例如，我们的辐射探测器的进步最有可能被纳入医疗诊断和治疗。此外，我们为我们的研究学生和工作人员提供了良好的培训环境，他们中的许多人继续在核电和辐射防护行业工作，帮助填补了目前的技能缺口。从更冒险的角度来看，我们对核异构体(能量陷阱)的特殊兴趣可能会导致新的能源应用。此外，我们热衷于与广大受众分享我们的专业知识，我们已经在媒体方面取得了令人羡慕的记录。

Nuclear physics research is at the dawn of a new era. For almost 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. There has been steady progress over the past 20 years in the development of beams of radioactive isotopes. Now it is becoming possible to generate intense beams of a wide range of short-lived isotopes, so-called 'radioactive beams', and thus vastly to expand the scope of experimental nuclear research. For example, it is becoming possible 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 its experimental research, the Surrey group is participating strongly in the development of two European radioactive-beam facilities: FAIR at GSI, Darmstadt, Germany, and SPIRAL at GANIL, Caen, France. While we are contributing to substantial technical developments at these facilities, the present grant request is focused on the exploitation of the capabilities that are already becoming available. To achieve our physics objectives, we also need to use several different 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. In the world-wide development of nuclear physics, there is a close connection between theory, experiment, and radiation detection techniques. A key feature of the Surrey group, unique within the UK, is our strength in all three of these areas. Our science goals are aligned with current STFC strategy for nuclear physics. 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 the Surrey 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. We need a more sophisticated understanding of the nuclear force, and this needs experimental information about these delicate nuclei to test our theoretical ideas and models. We also need better radiation detectors (more sensitive and more efficient) to make best use of the new radioactive beams. Therefore, theory, experiment, and detector developments go hand-in-hand as we push forward towards the nuclear limits. Our principal motivation is the basic science, and we contribute to the world sum of knowledge and understanding. Nevertheless, there are more-tangible benefits. For example, our radiation-detector advances are most likely to 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 and radiation protection industries, 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.