کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1884825 | 1043368 | 2007 | 6 صفحه PDF | دانلود رایگان |
A new version of computer program (LT v.10) offers a new concept of polymer spectrum analysis. The theoretical model takes into account a few processes in which positron is involved: the process of slow formation and localization of positronium (Ps), delay formation of positronium from shallow trapped electrons and positron trapping in irradiation-induced centers. The model was applied to two series of spectra for LDPE and HDPE collected at constant temperature (much below the glass temperature) as a function of measurement time. The Ps internal relaxation time and time of localization of Ps in a free-volume center were determined. The results show that the trapping rate of positron is strictly correlated with the amount of the shallow trapped electrons. That suggests a coupling between the positron and electron-trapping centers.
Journal: Radiation Physics and Chemistry - Volume 76, Issue 2, February 2007, Pages 291–296