Applications of LINAC-based positron beams in atomic physics are described. The following broad subject areas are treated; e** plus mobility and momentum transfer cross section determinations, angularly resolved and integral cross sections for e** plus -atomic processes plus charge transfer (Ps formation) type experiments, experiments with tunable positronium beams and experiments with thermal Ps sources. In addition, some discussion is given concerning the use of channel electron multiplier arrays (CEMAs) in conjunction with charge coupled devices (CCDs) as position sensitive detectors.