Future access to neutron sources

8. The Technology Panel concluded that “the UK science case requires access to the best possible neutron scattering facilities” to remain competitive with the best in the world. The Technology Panel said: “UK scientists occupy a major position in the exploitation of both facilities, with commensurate benefit to UK science and technology”. The Science and Technology Facilies Council's International Scientific Advisory Council (ISAC) endorsed the views of the Technology Panel and described the UK science case as "excellent ”.
9. The broad range of applications for neutrons makes them an essential tool in the discovery, understanding and applications of science in areas which are vital to the UK science and technology base. The UK has established a position of international leadership in the development of neutron-based techniques and, through facilities at ISIS and ILL, provides a unique platform to enable major contributions in areas crucial to society, such as in energy, health, transport and bioscience.

The UK has established a position of international leadership in the development of neutron-based techniques

10. While it is important to maximise the impact of the existing capabilities, it is essential to look forward to new opportunities and challenges. Chiefly, a next generation machine will allow increasingly complex systems to be analysed in real environments in real time. It is clear that increased power of neutron sources, together with ongoing advances in instrumentation, will continue to broaden the range of problems in science that can be tackled, thereby increasing the number of opportunities for breakthroughs that can be made. For example, higher power sources will enable experiments of higher resolution in both space and time, smaller sample sizes, and faster collection of data. Biological samples are often available only in small quantities, and stable for only a limited time, and samples such as crack tips are inherently small. Many spectroscopic techniques measure the small fraction of neutrons which undergo a change in energy and the accuracy of  measurement improves with higher power. The study of liquid-liquid interfaces requires neutrons to pass through a liquid layer at a shallow angle – higher intensity sources enhance neutron reflection. Extreme sample environments, such as pulsed magnetic fields, higher pressures, ultra-low temperatures and very high temperatures are also facilitated by increased source capability.

A next generation machine will allow increasingly complex systems to be analysed in real environments in real time

11. Higher specification sources can operate either in a short pulse mode (SPSS), similar to the existing ISIS or with longer pulse durations (LPSS) where the technical requirements associated with increasing the power are less severe but would require instrument development. However, while there is no single source which is best for all types of studies or disciplines it is important that UK scientists have access to, and can influence the development of, a hierarchy of complementary sources with a range of powers and pulse durations.
12. The future development of neutron sources will require international coordination and cooperation and they will be developed either in a single location or in several. Given the international lead which has been built up over the past 20 years, it is appropriate that the UK should exploit this expertise and be able to host new developments while maintaining and enhancing its existing experimental base.