Nuclear Structure & Reactions: Theory & Experiment

一百年来，原子核的探测或多或少都是通过研究稳定的束流和稳定的靶之间的碰撞来实现的。这限制了可以研究的原子核只是那些被认为存在的原子核的一小部分。对于制造所有元素(在各种恒星过程中)至关重要的大多数原子核都无法进行实验。全球核物理学的主要推动力，也是英国计划的一个关键优先事项，是通过使用短寿命放射性同位素产生的束流来接触和研究这些奇异的原子核。这反过来又表明，原子核的结构并不总是像稳定的原子核那样，而且人们发现，原子核在稳定性方面有令人惊讶的趋势，并且具有不同的形状，这将影响恒星和超新星内部的反应速度。在萨里/布莱顿，我们非常重视英国的这些优先事项和新的机会，我们在世界上最好的设施中寻找和领导制造这些放射性束流的计划。制造光束很困难，而且设备和研究工作都是国际规模的。萨里/布莱顿在这些设施中建造和运行创新的实验设备。目前的拨款申请集中于在最好的实验室开发这些能力。实验进展与理论密切相关，开发新的和更好的理论方法是萨里小组的标志。整个团队的一个突出特点是我们的理论和实验能力的强大融合，这是我们研究计划的关键，也是公认的罕见和宝贵的优势。我们的科学目标与目前STFC的核物理战略保持一致，这在核物理咨询小组的路线图中得到了详细的表达。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。目前尚不清楚中子和质子是否会表现出不同的集体行为，以及能在多大程度上表现出不同的集体行为，甚至还不知道有多少中子可以与给定数量的质子结合。正是这样的特征决定了恒星如何爆炸。为了解决这些问题，我们需要对核力有一个更复杂的理解，我们需要更强大的理论来将这种理解建立在计算中，我们还需要关于具有异常数量的中子相对于质子的原子核的实验信息，以便我们能够检验我们的理论想法。因此，当我们向核极限迈进时，理论和实验是齐头并进的。对核结合的概述表明，大约一半的预测核从未被观测到，而这个未知领域的绝大多数涉及到具有过剩中子的核。我们的许多活动都是针对这一“富含中子的”领域，利用放射性束流带来的新能力，并利用计算能力和分析理论的进步，为最新的观测带来卓越的新理论工具。我们的主要动机是基础科学和STFC的“大问题”，我们为世界的知识和理解做出了巨大贡献。辐射探测器使我们的工作动力可以被纳入医疗诊断和治疗以及环境管理中。我们在这些问题上与国家物理实验室进行了强有力的接触。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行业工作，帮助填补了目前的技能缺口。此外，我们热衷于与广大受众分享我们的专业知识，并积极推动公众参与议程。

For a hundred years, atomic nuclei have been probed more or less exclusively by studying collisions between stable beams and stable targets. This restricted the nuclei that could be studied to just a just a small fraction of those that are thought to exist. Most of the nuclei important to making all of the elements (in various stellar processes) have been inaccessible to experiment. The major thrust in nuclear physics worldwide, and a key priority in the UK's programme, is to reach out and study these exotic nuclei by using beams produced from short-lived radioactive isotopes. This in turn reveals that nuclear structure is not always like it seems to be for the stable nuclei, and nuclei are found to have surprising trends in stability and to have different shapes that will affect reaction rates inside stars and supernovae. At Surrey/Brighton we take these UK priorities and the new opportunities very much to heart, and we seek out and lead programmes at the world's best facilities for making these radioactive beams. To make the beams is difficult and the facilities - as well as the research effort - are international in scale. Surrey/Brighton builds and runs innovative experimental equipment at these facilities. The present grant request is focused on the exploitation of these capabilities at the best laboratories.Experimental progress is intimately linked with theory, and the development of novel and better theoretical approaches are a hallmark of the Surrey group. An outstanding feature of the group as a whole, which is key to our research plans and acknowledged as a rare and valuable strength, is our powerful 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's road map. 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. It is unknown whether, and to what extent, the neutrons and protons can show different collective behaviour or even how many neutrons can bind to a given number of protons. It is features such as these that determine how stars explode. To tackle these problems, we need a more sophisticated understanding of the nuclear force, we need more powerful theories that can build this understanding into the calculations, and we need experimental information about nuclei with unusual numbers of neutrons relative to protons so that we can test our theoretical ideas. 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. Much of our activity addresses this "neutron rich" territory, exploiting the new capabilities made possible with radioactive beams and exploiting advances in computational power and analytical theories to bring superior new theoretical tools to bear on the latest observations.Our principal motivation is the basic science and the STFC "big questions", and we contribute strongly to the world sum of knowledge and understanding. The radiation-detector advances that our work drives can be incorporated in medical diagnosis and treatment and in environmental management. We engage strongly with the National Physical Laboratory on these topics. 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. Furthermore, we have a keen interest in sharing our specialist knowledge with a wide audience, and actively pursue a public engagement agenda.