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What kind of information we can obtain from positron annihilation spectroscopy?

Funded under: FP6-JRC


Positron annihilation spectroscopy (PAS) is nowadays well recognized as a powerful tool of microstructure investigations of condensed matter, as a spectroscopic technique for the study of vacancy type defects, and as an additional technique in material study for registration also very low concentration of defects. Undoubtedly, PAS is a very suitable technique for defects study in the near surface region. In the report, following frequently asked questions (in connection to the possible benefit from application of positron annihilation techniques in material research) are analysed in details:
1. What is positron annihilation spectroscopy (PAS) and which techniques are used? (State of art focused on metals)
2. What is capability of these techniques?
3. Which parameters are studied?
4. What types of defects can be observed by PAS techniques? Can we see dislocations or nanodefects?
5. Is it possible to compare these techniques with other? Is there some complementing or synergy effect to TEM?
Since 1990-s PAS has been extensively used in the study of RPV steels. The positron annihilation technique can give essential information about the deterioration of the mechanical properties of RPV steels during their irradiation, which is known as neutron embrittlement. The lifetime of positrons trapped at radiation-induced vacancies, vacancy-impurity pairs, dislocations, micro voids, etc. is longer than that of free positrons in perfect region of the same material. As a result of the presence of open volume defects, the average positron lifetime observed in structural materials is found to increase with radiation damage.
Based on own author�s practical experiences in this area, the most relevant application of PAS are summarised in two papers dealing with PAS contribution in i) RPV steels of Russian design (Annex I) and ii) perspective materials foreseen for nuclear fusion (Annex II). These papers will be published elsewhere next year.

Additional information

Authors: SLUGEN V, European Commission, Joint Research Centre, Institute for Energy, Petten (NL)
Bibliographic Reference: EUR 22468 EN (2006), 94 pp. Free of charge
Availability: Available from European Commission, JRC Knowledge Management Unit, Ispra (IT) Tel: +39 033278 9893 Fax: +39 033278 5409 E-mail: or Bruxelles (BE) Tel: +32 2 295 76 24 Fax: +32 2 299 63 22
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