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Positron Annihilation Spectroscopy of Polymers and Rubbers

Polymers and Rubbers

  1. Josef Bartoš

Published Online: 15 SEP 2006

DOI: 10.1002/9780470027318.a2027

Encyclopedia of Analytical Chemistry

Encyclopedia of Analytical Chemistry

How to Cite

Bartoš, J. 2006. Positron Annihilation Spectroscopy of Polymers and Rubbers. Encyclopedia of Analytical Chemistry. .

Author Information

  1. Polymer Institute of the Slovak Academy of Sciences, Bratislava, Slovak Republic

Publication History

  1. Published Online: 15 SEP 2006

Abstract

Positron annihilation spectroscopy (PAS) is a common name for a set of techniques based on measurements and analysis of the annihilation characteristics of a positron e+ and its bound form with an electron e, so-called positronium (e+e) ≡ Ps. PAS includes three basic techniques:

  1. Positron annihilation lifetime spectroscopy (PALS)

  2. Angular correlation of annihilation radiation (ACAR)

  3. Doppler broadening spectroscopy (DBS).

These techniques measure the time of emission, energies and momenta of positron–electron annihilation photons, respectively. PALS measures positron and positronium lifetimes and their relative intensities, giving information about the structural–physical properties of condensed materials such as metals, ceramics and polymers, while ACAR and DBS provide information about the electron momentum and energy distribution in a material. The first technique is the most developed and it serves to characterize the microstructural features of the disordered phase of condensed matter, such as defects or free-volume holes.