| NUKLEONIKA 2013, 58(1):225-228
POSITRON ANNIHILATION IN PRECIOUS AND COMMON OPALSJan Chojcan1, Michał Sachanbiński2, Rafał Idczak1, Robert Konieczny1 1 University of Wrocław, Institute of Experimental Physics, 9 M. Borna Sq., 50-204 Wrocław, Poland 2 College of Handicraft and Management, 21 St. Macieja Sq., 50-244 Wrocław, Poland The nano-porosity structure of several non-crystalline opal samples of different origin was investigated with positronium atoms. The obtained data show that the structure depends on both the kind of opal (precious, common or hyalite) as well as the place of its creation (sedimentary or volcanic rocks). The sizes of the pores “seen” by positronium atoms are relatively small, not greater than about 1 nm for all studied samples which may suggest that the pores are located inside the silica matter from which the samples are made. Moreover, the pores detected in the “sedimentary” precious opals are smaller and have less diverse sizes than those found in “sedimentary” common opals and “volcanic” precious opals. Close X |