Temperature dependence of positron lifetime in ordered porous silica (SBA-3)

S. Kunishige, M. Koshimizu, K. Asai

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11 Citations (Scopus)


The temperature dependence of positron lifetime in uniform mesopores was analyzed. We used SBA-3 as the sample material, which possesses an ordered porous structure with uniform cylindrical mesopores. The positron lifetime corresponding to the annihilation in the mesopores increased gradually with a decrease in temperature down to 100 K, and its relative intensity also increased concomitantly. This result was attributed to the lower probability of the escape of the ortho-positronium (o-Ps) from the mesopores into the intergrain space at lower temperatures. An anomalous and sudden increase in the lifetime was observed at around 100 K; this result was in agreement with an increase in the positron lifetime reported in a previous study. It was revealed that the increase in the lifetime is very steep in cases of uniform mesopores, suggesting that the temperature dependence is influenced by the pore size.

Original languageEnglish
Pages (from-to)1088-1091
Number of pages4
JournalRadiation Physics and Chemistry
Issue number12
Publication statusPublished - 2009 Dec


  • Mesoporous silica
  • Positron lifetime
  • Positronium
  • SBA-3


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