Ejection of electrons and positrons in collisions of positronium with atoms

We discuss the observation of electrons and positrons ejected in collisions of positronium with atomic targets. We consider processes in which the target is excited or ionized or where the observed electron is ejected from the target rather than from the positronium. Example calculations based upon the impulse approximation and the first Bom approximation are presented for total ionization cross sections, cross sections differential in the longitudinal energy of the ejected particle, and double differential cross sections in the energy and angle of the ejectile. Comparison is made with experimental data where available. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.