Surface Analysis and Atomic Physics with Slow Positron Beams

Abstract

Recent advances in slow positron beam techniques are making it possible to study the interactions of low-energy positrons with gas molecules and solid surfaces and to measure the properties of free positronium atoms. New surface related results include the observation of surfaces with negative positron affinity and the thermionic emission of slow positronium atoms, low-energy positron diffraction measurements, and the sensitive detection of near-surface crystalline imperfections. Two recent successful experiments in atomic physics are the formation of the positronium negative ion and the optical excitation of positronium for high precisin spectroscopy. Prospects for a positron microscope and the study of exotic antimatter systems such as the two-component Fermi gas are based on the imminent possibility of enormous increases in the brightness and instantaneous intensity of positron beams.