Influence of Positron Irradiation on Positronium Formation in n-Alkanes

Positronium formation probability was investigated as a function of ir-radiation time and temperature for some long-chain saturated hydrocarbons (alkanes). Intensity of ortho-positronium component in the lifetime spec-trum depends on the concentration of trapped excess electrons, but also on concentration of radicals and ions acting as electron scavengers. The re-sults indicate the existence of two kinds of electron traps; those which are not emptied by thermal treatment disappear after several days of positron irradiation. PACS numbers: 36.10.Dr, 61.80.Fe, 78.70.Bj 1