Positronics and nanotechnologies: Possibilities of studying nanoobjects in critical engineering materials using positron annihilation spectrometry

It is shown that positron annihilation spectroscopy (PAS) is one of the efficient methods for determining the sizes of nanodefects (vacancies, vacancy clusters); free volumes of pores; cavities, and voids; their concentrations and the chemical composition at the annihilation site (location) in nanomaterials and other critical engineering materials. A brief review of experimental studies of nanodefects in porous silicon, silicon, and quartz monocrystal irradiated by protons as well as quartz powders are given.