Kobets A. Development and creation of a source of low-energy positrons and electrons for diagnostics of point defects in condensed matter

The thesis is devoted to the development and manufacture of low-energy positron source. Today, a number of applied problems in solid state physics require the use of sensitive research tools which can detect the absence of an atom in the material’s crystal lattice. Such a tool is Positron annihilation spectroscopy (PAS). Positron annihilation spectroscopy allows to detect structural defects with size ranging from single vacancy up to pores and concentration over 1 ppm. Nowadays, this technique is of a great interest due to the practical character of obtained results. It is successively applied to the field of solid state and applied physics, chemistry, materials science and surface engineering. Developed The source of slow positrons with a moderator based on solid neon is developed. The neon gas condenses on the work surface, which is cooled to a temperature of 5.5 K. The developed positron source design is cooled using a cryocooller. In contrast to the design with liquid helium cooling, this system requires significantly less time to cool the source to operating temperature. The maximum flux of slow positrons reaches 5106 e+/s. Keywords: beam, positron spectroscopy, positron, crystal lattice, aluminum, electron gun, vacuum chamber, solenoid.