Abstract

Postulated before 1920 to account for observations such as the fluctuating measured half-life of polonium and the unusual migration of polonium causing radioactive contamination throughout laboratories, by 1930 the phenomenon of aggregate recoil had become part of international textbook science. The formation of radioactive aggregates has been confirmed, but their migration is probably due either to volatility and diffusion or to electrostatic polarity and attraction. Knock-on recoil and sputtering may contribute to the release of such aggregates from solid surfaces, whereas carry-along recoil—the type of recoil event associated with the accepted theory of aggregate recoil—is shown here to run counter to known scientific principles