Manchester Experimental Nuclear Physics Consolidated Grant Request 2011

Nuclear Physics aims to understand the structure and dynamics of nuclear systems. It is key to understanding the Universe from the first microseconds of its inception through its history of star and galaxy formation where nuclear reactions play a key role in the generation of energy and the creation of elements. The field has applications that benefit society in areas from medicine and security to power production, and a strong impact on other fields of science.

The Manchester group makes leading edge contributions at an international level. Experimental work is performed at specific overseas facilities with focussed investment in the necessary instrumentation to carry out this work.

Experiment:
Atomic nuclei are a unique quantal laboratory in which microscopic as well as mesoscopic features, driven by effective two-body and three-body forces, can be studied. They are complex many-body systems, but often display unexpected regularities and simple excitation patterns that arise from underlying shell structure, pairing and collective modes of excitation. Such properties are also exhibited by simpler mesoscopic systems (for example, metallic clusters, quantum dots, and atomic condensates) the understanding of which draws heavily on techniques developed and honed in nuclear physics. A fundamental challenge is to understand nuclear properties ab-initio from the interplay of the strong, weak, and electromagnetic forces between individual nucleons. Recently, enormous progress has been made with such programmes for light nuclei. For heavier nuclei, shell, cluster and other beyond mean field many-body techniques, based on effective interactions, provide essential frameworks for correlating experimental data, yet still lack the refinement to reliably predict nuclear properties as one moves more than a few nucleons from well-studied stable nuclei.
Uniquely, radioactive beam facilities allow an exploration of nuclear properties using both approaches over a wide range of N (neutron number), Z (proton number), T (temperature or excitation energy) and I (angular momentum).
The key open questions the Manchester group will address include:
* Do new forms of collective motion occur far from the valley of nuclear stability?
* How does the ordering of quantum states, with all of its consequent implications for nuclear structure and reactions, alter in highly dilute or neutron-rich matter?

Theory:
To make precise connections between the structure and properties of the lightest, simple atomic nuclei and the underlying theory that describes the strong forces between nucleons, Quantum Chromodynamics. This is difficult because of the strength of the interaction. Even its fundamental degrees of freedom, quarks and gluons, are not the ones we see in nuclei. As the theory cannot be solved for situations relevant to nuclear physics, we work with "effective" field theories, built out of the appropriate degrees of freedom but incorporating robust constraints from the underlying theory, in particular its symmetries. An effective theory shouldn't be used at short distances where the underlying physics starts to be resolved. We apply a cut-off to mask the short-distance behaviour; a renormalisation approach is then used to ensures that predictions do not depend on cut-off scale. This approach is well-developed for couplings of photons and pions to single nucleons and for the forces between a pair of nucleons.
We now wish to extend the approach to larger nuclei, initially looking at ones with 3-4 nucleons. We will use a powerful variational method to determine the nuclear wave functions, starting from forces provided by the effective theories. With these wave functions, we will then calculate interactions of photons with these nuclei to learn more about how nucleons respond to external fields. Experiments of these nuclei can tell us about the properties of the neutron, which are not accessible by other means since it is an unstable particle.

Trained manpower at postgraduate and postdoctoral levels is in great demand in nuclear, software and instrumentation industries. Young scientists trained within academic nuclear physics are the only source of independent expertise in areas concerning radioactivity and radiation detection. The importance of this expertise can only increase in the future as handling of nuclear wastes and reactor decommissioning become even more important issues in society. The research undertaken will also directly inform the teaching of undergraduates at Manchester who will benefit from advanced courses involving examples from topical, current research issues.

Since nuclear physics is the fundamental science underpinning the nuclear sector, our expertise developed in research projects such as these allows us to host for two major postgraduate training programmes: the Coordinating Centre for NTEC (Nuclear Technology Education Consortium involving 12 UK universities providing Masters-level courses to the nuclear industry) and the EPSRC Industrial Doctorate Centre for Nuclear Engineering (a consortium of 8 universities, see above). We deliver core and options modules for NTEC, and we are quickly expanding other KT activities (eg courses given to EURATOM Nuclear Safeguards inspectors; leading involvement in a European project to design nuclear safety culture courses across the European nuclear sector; and nuclear codes training courses).

Members of the group have a long track record in improving the wider scientific culture by initiating scientific outreach activities. As examples of current activity: group members are organising events in association with the Rutherford centenary in 2011 including a public lecture series and an exhibition at the Manchester Museum of Science and Industry; one group member acts as science correspondent for the weekly "Slice of Science" section on Manchester's Unity Radio; contributions will be made to the annual school teacher's conference on nuclear physics organised by several northern universities. Plans for the future include: participation in the NW Gifted and Talented Regional Partnership; "Raising Awareness of the Work of Nuclear Physicists", an STFC Large Award Proposal from Dalton and MoSI for Key Stage 4/5 and A-Level students; workshops for Key Stage 3/4 supported by the National Nuclear Laboratory and Urenco.
Group members have also been able to influence UK and International Policy on nuclear related issues via participation in select committee activities and by representing the UK at a variety of international meetings related to the nuclear industry and skills.

Nuclear data and technological expertise in the group will be used to make measurements relevant to the nuclear industry by improving a variety of important nuclear cross sections. This will improve the Joint European Fission-Fusion database, used throughout the nuclear industry for design and planning current operations. Improvement in the quality of the data automatically improves the safety and reliability of calculations made.

Work is on-going to identify and develop an alternative energy supply to Pu-238, for which world stocks are about to run out, involving neutron, gamma and beta dose calculations using radiation transport codes to assess both the dose to on-board equipment and also to personnel making the nuclear battery prototypes and preparing the craft for launch.

The group has supported medical research using short-lived positron emitters at the Wolfson Medical Imaging Centre, by supervising MPhys and MSc students to help WMIC's research project work. In the near future, there is the opportunity for us to contribute to developing separated radioisotope production at the medical cyclotron using laser techniques. Group members are involved in projects to improve SPECT imaging at the Christie hospital, with potential to commission commercial software.

For more detailed information, see accompanying paperwork.