Galileo’s remark, “measure what is measurable, and make measurable what is not so”, says it all with respect to contemporary quantitative science. He gives pride of place not only to measurement, but also to extending the means of measurement beyond its current circle of light.
While these principles are broadly respected, the latter tends to be somewhat narrowly construed to our detriment. The particular example I have in mind is that of accelerators – although there are others. The range of applications of accelerators to science – and technological applications as well – has grown steadily, particularly with the rapidly expanding use of synchrotron radiation for the life, materials and engineering sciences, to say nothing of the growing use of accelerators for neutron production in these same fields. There are two excellent reasons for the stakeholders in these fields to take a more active role in this part of instrumentation development:
• the control of increasing facility costs needs intellectual input;
• the need for new capabilities in pushing forward the frontiers in the various sciences demands involvement by those who best understand these capabilities.
Before proceeding, it would be best to review the history of accelerator science and technology. The first half of the 20th century saw rapid development of the various accelerator types we use today. With a few exceptions, these developments were driven by the scientists who needed them for their research, both scientists working in university environments and those in the larger facilities that began to grow after the Second World War. With the scientific need for higher and higher energies enabled by the discovery of the alternating gradient principle and the development of systematic design methods for accelerators, a specialization of labour developed in which accelerator science became an identifiable speciality diverging from nuclear and particle science. This, coupled with the closing of most university accelerators, forced by the need for ever larger facilities, has effectively removed intellectual involvement in accelerator development from most university campuses (with a few notable exceptions). To continue with the example of particle physics, today only 13% of experimental particle physicists in North America claim involvement in accelerator work, and two-thirds of them reside at national laboratories. By contrast, three-quarters of experimental particle scientists reside at universities. The health of accelerator-based science depends on redressing this imbalance in intellectual centres of gravity.
While the laboratory structure that has developed, driven by these trends, has been hugely successful, the need for reconsideration is apparent. Progress at the energy frontier of particle science is now strongly compromised by the cost of the required facilities. Cost is also a factor in facilities for radiation production for the life, materials and engineering sciences – though not yet as urgent as for particle science. However, technical advances in improving brightness, coherence and time structure of radiation-producing accelerators are needed to continue advancing on the important frontiers. These advances need the intellectual input of those who know exactly what characteristics are needed, and who are capable of matching technical possibilities to these needs.
One often hears that the culture changes implied by these observations cannot take place because the subjects are not themselves accelerator specialists – how can one contribute to such a mature and well developed field dominated by experts? The point is that the problems to be solved and the concepts to be developed have significant components outside of the traditional accelerator science and technology purview – just the sort of instrument-developing activity that good experimental scientists have always engaged in. Of course the specialists are needed, but new ideas “outside the box” are required. It should be obvious that at this stage of world science, more intellectual input into this part of instrument development is needed. It’s a matter of perspective. University and lab scientists, and their cultural underpinnings, need to see themselves in this picture if we are to continue the progress that can be afforded by the use of accelerators.