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Nanoporous zirconia is used in gas sensors and as a membrane in high-temperature fuel cells. In the present work, positron annihilation spectroscopy and transmission electron microscopy (TEM) were performed on pure zirconia-sintered nanopowders, to determine the porosity. The ortho-positronium annihilation parameter R of zirconia samples, treated at 800°C and 700°C and annealed in oxygen–nitrogen atmosphere with different O2 contents, were obtained. The photoluminescence, positron annihilation spectroscopy, and TEM studies show presence of defects in all samples. Furthermore, the positron annihilation studies indicate a presence of large free volumes (of the order of few atomic units, at least), open towards the nanocrystals surface what was confirmed by TEM observations which detected a few types of defects such as voids within ≈2–4 interplane distances, stacking faults, terraces and point defects.

We report preliminary performance tests of an ORTEC PLS lifetime system based on plastic scintillators and analog electronic system. A variety of samples was measured, from metals (Cu, stainless steel), across semiconductors (Cz-grown silicon, ZnSe) to nanostructured ceramics (ZrO2). All results obtained are compatible with literature reports and indicate the lifetime resolution of the whole system as 180 ps.

Results of positron annihilation lifetime measurements of three organic liquids: benzene (C 6 H 6), cyclohexane (C 6 H 12) and methanol (CH 3 OH) are reported. The lifetime spectra are acquired at several temperatures for non-degassed, degassed and oxygen-saturated samples. The influence of oxygen on each lifetime and intensity component is discussed. Comparison of lifetime components with experiments in gas phase is done.

This paper reports on the results of positron annihilation lifetime measurements of three organic liquids: benzene (C6H6), cyclohexane (C6H12), and methanol (CH3OH). The lifetime spectra are acquired at different temperatures for non-degassed, degassed, and oxygen-saturated samples, at temperatures between 5 • C and 25 • C. The spectra are analyzed using a standard three-exponential model. The influence of oxygen on each lifetime and intensity component is discussed.