The Creation of High Quality Positron Beams Using Traps

摘要

High quality positron beams are currently used for a variety of applications in science and technology. One of the most demanding applications is as analytical tools for surface and materials science, where ultra-short positron pulses (<200 ps) and microscopic beams (< 1 micron in diameter) are desirable. Positron traps offer a qualitatively new method for beam formation and manipulation that has significant advantages in efficiency, flexibility, and cost over current beam conditioning techniques. One important capability is brightness enhancement by radial compression of the positron plasma using the rotating wall technique developed for electron and ion plasmas. A second capability is the production of ultra-short positron pulses required for positron annihilation lifetime spcctroscopy. This can be accomplished using a trap by means of the simple technique of quadratic potential bunching, thus avoiding multiple stages of rf bunching currently used to produce pulsed positron beams.