The creation of high quality positron beams using traps

Abstract

Abstract. 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 spectroscopy. 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.

Design and Simulation of a Trap-Based Pulsed Slow Positron Beam

“…Positron annihilation spectroscopy has become a useful probe to study metal and alloy, semiconductor, nanomaterials, and polymers, etc. Recently, positron annihilation spectroscopy has capability to investigate material surface/interface, thin solid films [1,2], and even 3-dimensionally image defects distributions using a variable energy pulsed slow positron beam with high positron flux and brightness [3][4][5]. Improvement of the time resolution of positron pulse of a pulsed slow positron beam is a key issue for extending its applications in material science and fundamental physics [6,7].…”