Nuclear physics research was the birth-place of charged-particle accelerators and for many decades their main ‘raison d'être’. This has given them a somewhat specialised and academic image in the eyes of the general public and indeed accelerators and storage rings do provide an extremely rich field for the study of fundamental physics principles. However, this academic image is fast changing as the applications for accelerators become more diversified. They are already well established in radiation therapy, ion implantation and isotope production. Synchrotron light sources form a large and rapidly growing branch of the accelerator family. The spallation neutron source is based on an accelerator and there are many small storage rings for research around the world relying on sophisticated accelerator technologies such as stochastic and electron cooling. In time accelerators may be used for the bulk sterilisation of food and waste products, for the cleaning of exhaust gases from factories, or as the drivers in inertial fusion devices.

During the first third of our century, natural radioactivity furnished the main source of energetic particles for research in atomic physics. Let us mention a famous example. At McGill University, Montreal, Canada, in 1906, Rutherford bombarded a thin mica sheet with alpha particles from a natural radioactive source. He observed occasional scattering, but most of the alpha particles traversed the mica without deviating or damaging the sheet.