Nuclear Physics Consolidated Grant (Equipment)

原子核由质子和中子组成，每个粒子本身都由夸克组成。原子核形成了原子中心的微小质量核心。然而，这种知识并不允许我们对任何给定的原子核或同位素的行为做出完整的预测。该系统过于复杂，涉及四种基本力中的三种：电磁力、弱核力和强核力。原子核的行为通常被描述为一种紧急现象，因为它不容易从其组成部分中预测出来。这推动了理论工作和以精确测量为基准的理论的需要。我们的研究旨在研究原子核的基本性质、宇宙中元素的起源以及核技术的应用。我们研究原子核的稳定性极限，特别是那些质子过剩的原子核和具有相同数目的质子和中子的原子核(N=Z原子核)。N=Z核表现出特殊的对称性，而偏离这些对称性的情况告诉我们关于竞争核模型有效性的详细信息。这样的测量非常具有挑战性，因为这些原子核很难生产出任何数量的核来进行实验。我们的方案使用了世界各地核物理的一些主要设施，在那里可以产生这种奇特的原子核。我们的工作包括研究质子和中子如何在N=Z原子核中相互作用，以及核子(例如进入阿尔法粒子)在这种原子核中聚集的程度。在我们的工作中，我们的目标是添加与其中三个区域中的核有关的特定问题，(I)质量70附近的N=Z核，(Ii)质量150附近的形变核和(Iii)中子缺乏铅区周围的核，迄今为止在非常低的激发能下观察到了原子核形状共存的最好例子之一。我们研究原子核结构的另一个方面与它们的形状有关。原子核的一个显著特性是它可以采用不同的形状：球形、扁圆形(聪明的形状)和长方形(橄榄球形状)，通常只需很少的能量成本。从理论上讲，预测原子核的形状以及当原子核被激发(假设有更多的能量)时这种形状是如何演变的是非常具有挑战性的。从实验上确定原子核的形状有助于区分相互竞争的原子核模型，并确定我们的理论理解。在核素图的许多区域都发现了与核形状有关的核结构效应和形状共存现象。我们研究的第三个线索是恒星中化学元素的起源，以及核物理在这个问题中所扮演的角色。有些元素和同位素只有在非常热和奇异的事件中才会产生，例如正在爆炸的恒星：新星和超新星。在这些事件中，会发生一系列快速的核反应。我们试图通过在实验室中复制这些反应来了解这些反应发生的速度有多快。这是非常具有挑战性的，因为这些研究中涉及的许多原子核本身就具有放射性，很难产生。然而，我们能够推进我们对化学元素是如何产生的理解。最后一个研究领域是对核裂变机制的研究，重点是探索这些机制是如何在远离众所周知的核的超离线区的核中发展的，在最重的核甚至在它们产生后发生自发裂变的情况下，核会经历诱发裂解。我们关于这些新的裂变区域的数据，例如质量180附近的轻汞同位素，对目前的核裂变过程模型提出了挑战。我们在这方面提出的工作将提供有关极端奇异核的新数据，以帮助进一步发展裂变过程的模型。

The atomic nucleus, which forms the tiny massive core at the centre of the atom, is composed of protons and neutrons and each of these particles are themselves comprised of quarks. However, this knowledge does not allow us to make a complete prediction of the behaviour of any given nucleus or isotope. The system is too complex, involving three of the four fundamental forces: the electromagnetic, weak and strong nuclear forces. The behaviour of the nucleus is often described as an emergent phenomenon as it cannot be readily predicted from its component parts. This drives theoretical effort and the need to benchmark theory with precision measurements. Our research is aimed at studying the funadamental properties of atomic nuclei, the origin of elements in the cosmos and applications of nuclear technology. We study nuclei on the very limits of stability, in particular those with an excess of protons, and those which have the same number of protons and neutrons (N=Z nuclei). The N=Z nuclei exhibit special symmetries and deviations from these symmetries tell us very detailed information on the validity of competing nuclear models. Such measurements are very challenging as these nuclei are very difficult to produce in any quantity to perform experiments on. Our programme uses some of the principal facilities for nuclear physics worldwide where such exotic nuclei can be produced. Our work involves studies of how protons and neutrons interact in N=Z nuclei and to what extent the clustering of nucleons (eg into alpha particles) occurs in such nuclei. In our work we aim to addess specific questions related to nuclei residing in three of these regions, (i) N=Z nuclei around mass 70, (ii) deformed nuclei around mass 150 and (iii) nuclei around the neutron deficient lead region, where one of the best examples of nuclear shape co-existence has been observed to date at very low excitation energy. A further aspect of our research into the structure of nuclei concerns their shape. It is a remarkable property of the nucleus that it can adopt different shapes: spherical, oblate (smartie-shaped) and prolate (rugby-ball shaped) often for a small costs in energy. Predicting the shape of a nucleus and how this shape evolves as the nucleus is excited (given more energy) is extremely challenging from a theoretical perspective. Determining nuclear shape experimentally can help to discriminate between competing models of the nucleus and pin down our theoretical understanding. Nuclear structure effects relating to nuclear shapes and the phenomenon of shape co-existence are found in many regions of the chart of the nuclides. A third strand of our research is into the origin of the chemical elements in stars, and the role played by nuclear physics in this question. Some elements and isotopes are only produced in very hot and exotic events such as exploding stars: novae and supernovae. In these events, a rapid series of nuclear reactions takes place. We seek to understand how rapidly such reactions take place by reproducing them in the laboratory. This is very challenging as many of the nuclei involved in these studies are themselves radioactive and difficult to produce. Nevertheless, we are able to advance our understanding of how the chemical elements are created. The final area of research is into the mechanisms of nuclear fission, with emphasis on exploring how these develop in nuclei that reside away from the well known transactinide region of nuclei which can undergo induced fisson or in the case of the heaviest nuclei even spontaneous fission following their creation. Our data on these new regions of fission, such as in the light mercury isotopes around mass 180, are presenting challenges to the present models of the nuclear fission process. Our proposed work in this area will provide new data on extremely exotic nuclei to help develop the models of the fission process further.