AGATA: Precision Spectroscopy of Exotic Nuclei

原子核的结构，即质子和中子如何排列以及它们如何相互作用形成复杂的原子核，对日常生活有着决定性的影响，从地球上碳基生命的存在到关键的核物理应用，如碳年代测定。我们对原子核结构的理解仍然是难以捉摸的，并且依赖于提供原子核关键观测值的复杂实验。例如，我们的实验使用粒子加速器，使以高达50%光速运动的原子核在静止物质上碰撞，以诱导核反应。通常情况下，不到百万分之一的反应会产生研究中的原子核，并且感兴趣的状态通常不到十亿分之一秒。为了探测这种罕见的事件并测量我们所追求的性质，我们需要开发非常灵敏的仪器。 该项目支持开发最灵敏的“显微镜”之一，AGATA光谱仪，用于探测加速器引起的核反应过程中发射的伽马射线。这些伽马射线携带着关于（剧烈）核反应期间发生的事情的关键信息。通过研究伽马射线的能量和方向，我们可以提取碰撞中涉及的原子核的性质。我们的研究结果将有助于解决现代核科学中的关键问题。AGATA是伽马射线探测的一个巨大进步，在医学成像、天体物理学、核保障和放射性废物监测方面有着广泛的应用，并为核结构研究引入了新的探测能力。事实上，这项工作所推动的仪器和技术进步以及相关人员所获得的知识将在广泛的应用中发挥重要作用，例如在医学和工业中。例如，在医学成像中，伽马射线能量的重建及其方向的确定将导致图像的极大改善。另一个受益者将是核保障措施，其中一个大问题是确定废物中同位素的范围及其数量。

The structure of the atomic nuclei, i.e. how protons and neutrons arrange themselves and how they interact among each other to form complex nuclei, has a decisive impact on everyday life, from the very existence of carbon-based life on Earth to critical nuclear physics applications such as carbon dating. Our understanding of nuclear structure is still elusive and relies on sophisticated experiments that deliver critical observables of atomic nuclei. For example, our experiments use particle accelerators that collide nuclei travelling at up to 50% the speed of light on stationary material to induce nuclear reactions. Typically, fewer than one in a million reactions will create the nucleus under study and the states of interest live, typically for less than a billionth of a second. To detect such rare events and measure the properties we are after, we need to develop very sensitive instruments. This project supports the development of one of the most sensitive "microscopes", the AGATA spectrometer, for gamma rays that are emitted during the accelerator-induced nuclear reactions. These gamma rays carry critical information about what happened during the (violent) nuclear reaction. By studying the energy and direction of the gamma rays, we can extract the properties of the atomic nuclei that were involved in the collisions. Our results will help address critical questions in modern nuclear science. AGATA constitutes a dramatic advance in gamma-ray detection that has wide ranging applications in medical imaging, astrophysics, nuclear safeguards and radioactive-waste monitoring, as well as introducing new detection capability for nuclear-structure studies. Indeed, the instrumentation and technical advances driven by this work and the knowledge gained by those involved will be important in a wide range of applications, such as in medicine and industry. For example, in medical imaging, reconstruction of the gamma-ray energies and determination of their direction will result in vastly improved images. Another beneficiary will be in nuclear safeguards where one of the big problems is the identification of the range of isotopes in waste and the determination of their quantities.