Positrons and Positronium in Gases

TLDR: In this paper, a positron and electron interactions with atomic systems are discussed. But the authors point out that the absence of symmetries can make calculations more difficult, and positron interactions are not symmetric.

Abstract: Publisher Summary There are significant physical differences between positron and electron interactions with atomic systems Effects of the identity of the projectile with components of the target, exchange effects, do not arise in positron problems Although this would apparently lead to simplification, in fact the concomitant absence of symmetries can make calculations more difficult If its kinetic energy is high enough, a positron may pick up an electron from the target, forming the very light and large positronium atom; or it may, as do electrons, excite or ionize the target At sufficiently low energies, a positron will scatter only elastically Time to pulse-height converters, whose outputs are fed to multichannel pulse-height analyzers, are used in such work