Studies of shapes and stability in exotic nuclei

The shape of an atomic nucleus is one of its most fundamental properties. The simplest shape that a nucleus can have is a sphere. Nuclei that have closed shells of neutrons and protons are spherical. Away from closed shells, nuclei can become non-spherical, or deformed. The most common deformed shapes are rugby-ball (prolate) shapes or pumpkin (oblate) shapes, both of which are termed quadrupole deformation. Some nuclei can take on a reflection-asymmetric pear shape, termed as octupole deformation while some others can take a shape of a spinning top, termed as hexadecapole deformation. In a quantum-mechanical system of particles, the emergence of a shape is a direct consequence of the interaction between the constituent particles. Therefore, shape studies of nuclei can probe nucleon-nucleon interactions and, in particular, neutron-proton interactions, which are yet to be fully understood. The nuclear shape can also affect the characteristics of particle and cluster decays, which are currently topics at the forefront of nuclear-structure physics, particularly in the regions at the limits of stability. Experimental studies that are focused on the measurement of nuclear deformations will allow a comparison of the measured shapes with those predicted by theoretical calculations to test the validity of models. In general, the shapes of nuclei indisputably have an important impact on several areas of nuclear physics and some other areas such as the origin of elements in astrophysical environments. Consequently, the proposed experimental studies of shapes, neutron-proton interactions and particle decays are at the forefront of current nuclear-physics research.

The proposed work will increase UK/UWS presence at CERN-ISOLDE and will help to establish new collaborations and strengthen the existing network. This will subsequently strengthen the UK influence on the roadmap of future research in this area. The results of this research will help in providing directions to theoretical groups in improving nuclear models. Some of the information about shape configurations and low-lying level structures are directly used in nuclear astrophysics in interpreting elemental abundances. Information, especially about self-conjugate nuclei, is used to test unitarity of the CKM matrix and thereby test the standard model of particle physics

Ph.D. students and PDRAs connected with the research will be trained with which they will become attractive candidates for alternative sectors such as nuclear medicine, the nuclear industry and various companies. For example, in southern/central Scotland, the Chapelcross and Hunterston A power stations are being decommissioned and the Hunterston B and Torness power stations will be decommissioned in a few years' time: there is, therefore, a need for a skilled workforce in the local area. In the West of Scotland, the nuclear submarine installation at Faslane, will have staff will need training in radiation safety and radiation detection and environmental monitoring. Detector companies such as Kromek, Nuvia, and Micron Semiconductors Ltd. require detector development specialists.

The GEANT4 and GATE simulation packages will be used during the proposed work for designing experiments and building detectors using specifically developed codes. These codes will be directly adaptable for medical imaging using PET and
Single Photon Emission Computed Tomography (SPECT). Beam development and accelerator technology work needed for the proposed work has applications in health sector namely this knowledge is useful in producing radioactive isotopes; an example is the MEDICIS project at CERN. Detector developments can be useful for installation of beam diagnostics at medical imaging facilities such as the Beatson West of Scotland Cancer Centre.

Outreach involving both school teachers and pupils at the laboratories in UWS will help promote the importance of physics and STEM subjects. Outreach could include lectures or presentations about detector setups and principles of radiation detection and their applications in day-to-day life and in physics experiments. To further publicise the research, presentations will be given, for example, via Café Scientifique, a programme of talks that takes place outside the traditional academic context, in cafes, restaurants, and pubs for the general public. To address the fact that nuclear physics is still a highly debated, controversial, and often-misunderstood topic among the general public, talks will be designed on topics, covering nuclear energy, nuclear astrophysics, nuclear technology and applications, especially imaging, medicine, and radiotherapy.