Samila A. Structural and functional synthesis of the radioelectronic means for pulsed spectroscopy of materials with quadrupole nuclei of atoms.

The thesis is dedicated to development of scientific basis and hardware-software imple-mentation of fundamentally new solutions for the experimental methods deployment of pulsed Fourier spectroscopy of nuclear quadrupole resonance (NQR). Scientific investigations and developments represented in the thesis are based on solving the algorithmic, circuit, configuration-structural problems whose solution allowed achieving the purpose of the study, namely implementation of hardware-software complex radio technical system of recording NQR signals by improving pulse excitation method and the algorithms of informational transformation of spin induction decay signals to solve the problem of accuracy of the study of semiconductor structures of small volumes. A simulation model of pulsed method for NQR observation was developed on the basis of single-coil coherent Fourier radio spectrometer without carrier frequency conversion. Com-puter simulation of signal transformations of the free induction signal and spin echo in radio frequency paths of pulsed radio spectrometer at sinusoidal and noise excitation of resonance was carried out. The dependences of parameters of signal energy spectra at the output of transmitter of NQR pulsed spectrometer on the duration of sine and noise excitation pulses were studied. The energy efficiency was calculated, and the laboratory model of energy-efficient broadband transmitter was developed that can be used in the study of isotopes with quadrupole moments 14N, 35Cl, 63Cu, 69Ga, 71Ga, 113In, 115In, etc. A parametric estimation of the efficiency of generation algorithms most suitable for syn-thesis of digital periodic signals on the basis of embedded hardware systems was performed. On the basis of modeling syntax of dynamic modes in logical structures, formation algorithms of multi-pulse Han, Carr-Purcell, and Meiboom-Gill sequences were developed for the relaxation spectroscopy of nuclear quadrupole resonance. A hardware-software data collection system for pulsed NQR spectrometer was developed. Experimental testing of coherent laboratory radio spectrometer based on a multi-functional software-controlled digital computing core was performed by pulsed observation of nuclear quadrupole resonance in small volumes of layered semiconductor crystals GaSe and InSe for the purpose of studying their quality and sensor properties.