Creation of a monoenergetic pulsed positron beam

Summary form only given. We have developed a versatile, pulsed source of cold (0.018 eV FWHM), low-energy positrons (E/spl sim/0-9 eV). Ten microsecond duration pulses of 10/sup 5/ positrons are extracted from a thermalized, room temperature positron plasma stored in a Penning trap. The frequency, duration, and amplitude of the pulses can be varied over a wide range. This technique allows for generation of electron pulses by simply inverting the polarity of all electrode potentials. Using this technique, we have also generated quasi steady state electron and positron beams with comparable energy resolution. There are numerous potential applications of such a source of intense, cold positrons. Examples include material surface characterization, such as depth profiling, positron and positronium gas scattering, and annihilation studies.