Papers by Author: K. Havancsák

Abstract: Positron annihilation lifetime (LT) measurements were used to study the influence of addition of iron on ortho-positronium (o-Ps) in micro and mesoporous media. Three types of porous samples containing iron were chosen for the investigation. LT spectra were decomposed to four components in the 0.1 - 50 ns lifetime range. An attempt is made to correlate the data with sites occupied by iron in the framework as derived from Mössbauer studies. No significant correlation could be detected in this respect. Instead, dominating role of presence or absence of iron can be deduced. Certain influence can also be attributed to the presence of adsorbed water.