AGATA: Precision Spectroscopy of Exotic Nuclei

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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.