The interaction of positronium with paramagnetic surface defect at low temperatures in fine Al2O3 powders

A study of inter-crystallite spaces in some polycrystalline inorganic systems using positron annihilation lifetime spectroscopy

“…Obviously, the longest lived component is associated with o-Ps pick-off annihilation in the inter-crystallite spaces (Paulin and Ambrosino, 1968). This was confirmed also by Bartenev et al, 1969;Weber and Lynn, 2003;Van Waenberge and Dauwe, 2003. We have studied Al 2 O 3 (Shantarovich et al, 2005a, b), hydroxi-apatite Ca 10 (PO 4 ) 6 (OH) 2 including samples where Ca(II) ions were partially replaced by threevalence Europium Eu(III) ions, and also vaterit samples CaCO 3 .…”