Positronics and nanotechnologies: Possibilities of studying nanoobjects in materials and nanomaterials by the method of positron-annihilation spectroscopy

The method of positron-annihilation spectroscopy is shown to be one of the most efficient methods for determining sizes of nanoobjects (vacancies, vacancy clusters); free volumes of pores, cavities, and hollows; and their concentrations and chemical composition at the point of annihilation in porous systems and some defective materials (and generally in a lot of technologically important materials and nanomaterials). Experimental investigations of nanodefects in porous silicon, silicon, and quartz single crystals irradiated with protons and in quartz powders are briefly reviewed.