Surface physics with slow positron beams

Studies of solid surfaces by slow positron impact have seen notable successes in the last 20 years, and much effort is still concentrated in this area. However, the application of positron diffraction, re-emission or annihilation as a surface probe has yet to become widely established, primarily as a result of the relatively low intensities of high-quality positron beams. This paper reviews the current status of experimental positron-based research on surfaces and considers the prospects for future developments.