AGATA: Precision Spectroscopy of Exotic Nuclei

AGATA是一种专门设计用于实现激发态核的精确光谱分析的工具。强大的伽马射线光谱仪对于核结构研究至关重要，而AGATA作为欧洲领先的伽马射线设备，在所有需要束内伽马射线光谱能力的欧洲主要设施中需求量非常大。因此，AGATA的科学范围非常广泛，并与这些设施的核结构物理长期计划密切相关。科学计划与STFC科学挑战保持一致，从中出现优先事项，在STFC核物理路线图中突出显示。这些问题包括：是什么决定了核存在的极限，在核束缚的极限处是否有新的结构和对称形式？是什么机制促使复杂原子核中出现简单模式？研究核稳定性极限时的结构是至关重要的，例如，为了理解有效核相互作用的同位旋依赖性，从单个核子的性质解释集体现象，以及建立核存在的极限。很明显，我们教科书上关于原子核结构的许多观点都需要修改。例如，核壳模型中的幻数值不再神圣不可侵犯，核子-核子相互作用的强度意味着中子（质子）壳闭合的位置随质子（中子）数而变化。现在，可以存在的富中子核的数量预计将远远超过以前的想法：改进的核理论，包括对相关性和聚类的更现实的估计，预测中子滴线似乎在不断后退。AGATA的高分辨率与新的高强度放射性离子束设施相结合，将使我们应对这些新挑战的能力发生重大变化。

AGATA is a tool specifically designed to enable precision spectroscopy of excited nuclear states. A powerful gamma-ray spectrometer is essential for nuclear structure studies, and AGATA - as Europe's leading gamma-ray device - is in very high demand at all the major European facilities that require in-beam gamma-ray spectroscopy capability for their science programmes. The AGATA science is, therefore, exceptionally broad-ranging and is strongly connected to the long-term plans for nuclear-structure physics at these facilities. The science programme is well aligned with the STFC Science Challenges, from which priorities emerge, highlighted in the STFC Nuclear Physics Roadmap. These include: What determines the limits of nuclear existence and are there new forms of structure and symmetry at the limits of nuclear binding? What mechanism drives the emergence of simple patterns in complex nuclei? The study of structure at the very limits of nuclear stability is crucial, for example, in order to understand the isospin dependence of the effective nuclear interaction, to explain collective phenomena from the properties of the individual nucleons, and to establish the limits of nuclear existence. It has become clear that many of our textbook ideas of nuclear structure need to be revised. For example, the values of the magic numbers in the nuclear shell model are no longer sacrosanct and the strength of the nucleon-nucleon interaction means that the position of the neutron (proton) shell closure varies with the proton (neutron) number. The number of neutron-rich nuclei which can exist is now expected to be far greater than previously thought: improvements nuclear theory, including more realistic estimates of correlations and clustering, predict a neutron drip-line which seems to be constantly receding. The combination of the high resolving power of AGATA with the new high-intensity radioactive ion beam facilities will provide a step-change in our capability to address these emerging challenges.