QUASI-POSITRONIUM IN POLYETHYLENE TEREPHTHALATE - TEMPERATURE AND MAGNETIC QUENCHING EFFECTS

The features of the positron-electron bound system (quasi-positronium, qPs) in the semicrystalline polymer polyethylene terephthalate (mylar) are obtained while studying the dependence of the ortho-qPs lifetime on temperature in the range of 25-105-degrees-C, in the presence as well as in the absence of magnetic fields. In particular, the 'anomalous' effect, previously discovered by Bisi et al. at room temperature, is maintained at higher temperature.