University of the West of Scotland Nuclear Physics Group Consolidated Grant

It is just over 100 years since Ernest Rutherford's pioneering experiments which demonstrated the existence of the atomic nucleus. In the century that has followed, landmark developments, such as the inception of the nuclear shell model in the 1940s, the construction of heavy-ion accelerators in the 1960s, and major ongoing advances in nuclear-detector techniques, have firmly established nuclear physics as an international activity at the forefront of scientific research. In the past few decades, the quest to understand the properties of exotic nuclei ever further from the valley of stability has led to considerable experimental progress. The programme of research described in this Consolidated Grant application covers research into the structure and properties of atomic nuclei that lie far from stability. The overarching aim of our research programme is to achieve a better understanding of the structure and behaviour of exotic nuclei, on both the neutron-rich and proton-rich sides of the valley of stability, and for heavy nuclei.

Recent experimental observations, supported by theoretical calculations, have begun to suggest that the structure of exotic nuclei may be different from nuclei near stability. For example, the well-known sequence of magic numbers, corresponding to energy gaps in nuclear shell structure, is now thought to change in nuclei with an extreme excess of neutrons. The evidence for such a change is already convincing around neutron number N=20, and similar effects are expected for the other shell gaps at N=28, 50, and 82. In order to provide a test of nuclear models, experimental data are needed. In this respect, we will primarily focus our research on two areas of the nuclear chart, close to two doubly-magic nuclei: the proton-rich nuclei around Sn100 (N=Z=50) and the neutron-rich nuclei close to Sn132 (Z=50, N=82).

An important consideration in the description of an atomic nucleus is its shape. It is well established that nuclei with filled shells of neutrons and protons are spherical, and nuclei with partially-filled shells can become deformed. Indeed, it is the deformation of the nucleus into a prolate (rugby ball) shape, that leads to rotational excitations. A more exotic form of deformation is when the nucleus takes on a reflection-asymmetric "pear shape". The so-called "octupole deformation" is most prominent in localized regions of the nuclear chart, such as the light actinide region (radium, thorium, uranium nuclei with A~224) and the neutron-rich lanthanides (such as the A~144 barium and cerium nuclei). Although octupole correlations in nuclei have been studied for a number of years, recent developments in accelerator and detector technology will now allow experiments to be performed to provide new insights into this type of deformation. In our research programme, we will make a comprehensive study of octupole correlations in nuclei, focusing on the actinide and lanthanide regions, as well as the proton-rich nuclei near N=Z=56. The mirror-symmetry-violating pear shape allows for the search for physics that is responsible for the existent matter-antimatter symmetry violation.

Our research will primarily proceed using different methods of gamma-ray spectroscopy. We will use the best facilities available for the physics goals of the project. For example, we will carry out Coulomb excitation experiments at ISOLDE at CERN, fission-fragment spectroscopy at Institut Laue Langevin in Grenoble, and gamma-ray plus conversion electron spectroscopy with SAGE at JYFL in Jyväskylä, Finland. The funds requested here will provide support for postdoctoral research associates and PhD Students to help carry out this work, as well as funds for travel and subsistence. We have also requested funds to enable world leading theoretical nuclear physicists to visit our group to help with the interpretation of our results, and to provide important theoretical input into our experimental research programme.

This STFC-funded research will have a considerable impact on society. While some aspects will have an instant impact, and the benefits are immediately obvious, other aspects are more indirect, with the benefits realized in the long term.

A short-term impact is to attract the interest of school children, and hence to increase the numbers of students studying physics at university. The RCUK Review of UK Physics (Wakeham Report, 2008) stated that: "As part of a study looking at the societal benefits of UK research ... first year physics students were questioned in November 2007 as to which aspect of physics attracted them to the subject. In terms of most significant interest, fundamental particles, nuclear physics and astrophysics were the most cited, in this order." Dissemination of results from large-scale nuclear physics projects, such as AGATA and ISOLDE at CERN, will act as a carrot-on-a-stick to bring students into university to study physics. A greater number of physics students will equip the UK with a larger numerate and scientifically-minded workforce, which will have a positive effect on the economy. This impact will be maximized by presenting the results of this STFC-funded research to local schools and to the general public. This will be achieved by offering presentations and demonstrations to local schools and by communications such as web pages and newsletters.

Another impact of this research will be in the provision of skills to employees and future employees of the nuclear-power industry. With energy production high on political agendas, and with the imminent new-build of nuclear power stations and with the ongoing programme of decommissioning, the teaching of nuclear skills is presently in great demand. Our STFC-funded research will enable us to stay at the forefront of detector and technical developments. In turn, we will transfer our knowledge of, for example, radiation detection, to industry. We intend to carry out a programme of nuclear-skills training in several different ways. Firstly, we have recently developed a new undergraduate degree programme entitled "Physics with Nuclear Technology", which has a strong bias towards industrial applications of nuclear physics. Secondly, together with SUPA, we are developing a new MSc programme in Nuclear Technology, which will be focused on nuclear power, but which will also cover elements of other areas such as nuclear medicine and imaging. All of our skills training will be aimed at both local (Scottish) and UK students, and also students from abroad. We will thereby contribute to providing the UK with highly-skilled manpower who can help to meet future energy demands, and we will attract inward investment from overseas.

Our research will also have an impact in many other areas. Instrumentation and methods developed in nuclear-physics research have often found applications elsewhere. The use of nuclear and nuclear-related techniques in industry and society is widespread - some examples of which are mentioned below. In the oil industry, radioactive tracers are used to detect leaks in oil-well casings, to determine flow patterns and leaks in oil pipelines. Elsewhere in industry, tracers can also be used for wear analysis to monitor corrosion in engine parts, and radiography can be used to determine thicknesses of materials. Nuclear medical imaging has become commonplace in hospitals; such techniques have clear benefits to society and increase the quality of life. Cancer therapy using beams of gamma rays, electrons, protons, and carbon ions saves thousands of lives every year. Dating techniques such as radio-carbon dating and uranium-thorium dating have many applications, particularly in geophysical studies. These applications use methods and techniques that were developed in fundamental research in previous years and decades. Similarly, our STFC-funded research, proposed here, will lead to similar such applications in the future