In previous studies we have investigated artefacts which appear in analysed parameters of positron lifetime spectra containing distributed o-Ps lifetimes. Recently, we discovered also that the disagreements between the experimental positronium lifetime parameters and theoretical expectations, I 1 aI 3 b I p Ps aI o Ps 1a3 and t 1 b t p Ps , may be well understood by assuming a distribution of e + lifetimes in addition to an o-Ps lifetime distribution. In this paper we give further experimental evidence for these deviations by taking positron lifetime spectra of high statistical accuracy for various amorphous polymers. Furthermore, a systematic study of the influence of the widths of the e + and o-Ps lifetime distributions on the analysed lifetime parameters will be presented. The analysis of computer-generated spectra showed that all of the analysed lifetimes t 1 , t 2 and t 3 increase artificially with increasing width of the e + and o-Ps lifetime distributions. The intensity I 1 increases also, while I 2 and I 3 decrease. The deviations of I 1 aI 3 and t 1 from the theoretical expectations are mainly controlled by the width of the e + lifetime distribution. Suggestions for suitable constraints in the discrete-term analysis in order to get reliable lifetime parameters are also made.
In fru È heren Arbeiten haben wir Artefakte untersucht, die in analysierten Parametern von Positronenlebensdauerspektren auftreten, welche verteilte o-Ps-Lebenszeiten enthalten. Ku È rzlich entdeckten