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Relationship between Enhanced Positronium Formation and Enhanced Positron Trapping in Polymers at Low Temperature
- Source :
- Acta Physica Polonica A. 110:593-604
- Publication Year :
- 2006
- Publisher :
- Institute of Physics, Polish Academy of Sciences, 2006.
-
Abstract
- Positron annihilation lifetime spectroscopy is used for investigation of low-density polyethylene and ethylene-methyl methacrylate copolymers of 1.45, 3.0, and 5.4 mole% of methyl methacrylate. The lifetime spectra are collected at 30 K, one by one, as a function of elapsed time. In the computer analysis a new theoretical model is de eloped, which enables separating the annihilation from positron free state, its trapped state and bound state in positronium. The positron trapping rate ¹ and the enhanced positronium formation rate · are determined. The calculated values of ¹ and · turned out to be linearly correlated. This correlation presumably originates from an in°uence of trapped electrons on the trapping of positrons. The dependences of · on measurement time are determined for low-density polyethylene and ethylene-methyl methacrylate of different methyl methacrylate content. A theoretical model describing quantitatively the dependences is proposed. The model considers the processes of electron{ion recombination, electron trapping, and electron scavenging by dipolar carbonyl groups supplied by methyl methacrylate additives.
- Subjects :
- promieniowanie elektronowe
chemistry.chemical_classification
Materials science
pozytrony
Positron Lifetime Spectroscopy
Physics::Medical Physics
General Physics and Astronomy
Polymer
Positron trapping
Positronium
Condensed Matter::Soft Condensed Matter
promieniowanie pozytronowe
chemistry
Physics::Chemical Physics
Atomic physics
anihilacja pozytonów
Subjects
Details
- ISSN :
- 1898794X and 05874246
- Volume :
- 110
- Database :
- OpenAIRE
- Journal :
- Acta Physica Polonica A
- Accession number :
- edsair.doi.dedup.....aaf985d905b405a0cc4e39866397f09e