Thermalization of positrons

A rough outline of the thermalization of positrons (Green 1966 Brandt 1983). The time is measured from the "birth" of positron till the end of the stage... 

From a material-centered point of view, the thermalization of positrons is a process very similar to that of electrons. The initial stage of inelastic collisions and the electromagnetic slowing down process form the usual radiation products. In fluids and molecular or atomic solids, these are excited and ionized molecules, fi-ee radicals, and electrons. In metals, however, plasmon and phonon excitation also play significant roles in the thermalization of positrons. 

---