An ion microprobe unit was used to study silver isotope ratios in gold-bearing ores. It was found that for ores formed under high-temperature conditions the light isotope '''Ag is enriched. Low-temperature deposits are enriched in the heavy isotope 'wAg.The Cameca IMS-4f ion microprobe unit has been utilized for the analysis of '09Ag/'07Ag ratios in goldbearing minerals. The samples of ores and rocks studied represent various genetic types of Precambrian and Phanerozoic deposits that have recently been discovered in the Ukraine. Studies of silver isotopic ratios have yielded an interesting result: for the deposits formed under high-temperature conditions, enrichment of the light silver isotope was observed in gold specimens whereas low-temperature deposits were mainly characterized by heavy isotope enrichment. The differences in the values of light silver-isotope content in the surface layer and the main body allowed us to visualize the oxidation degree of gold grains in gold-bearing deposits and sources of their formation. The present paper is devoted to the investigation of gold-bearing minerals using the secondary ion mass spectrometry (SIMS) technique and the investigation of the possibility of using SIMS mass spectra for measurement of ion energy distributions, for isotopic analysis and to obtain images of element distribution over the surface in a single experiment. These are of importance for closer studies of the processes in question and for better understanding of the secondary ion formation mechanism.Demand for gold in recent years has led to a sharp rise in geological prospecting. At the same time, prospecting remains ineffective, owing to the use of procedures that do not allow unequivocal inferences about the prospects of a given geological area to be drawn. The reason is that the formation of deposits is extremely complicated. Processes that result in the localization of ore material are, as a rule, extended in space and time , and have a multistage character determined by the interaction of endogenic and exogenic factors. Geochemical investigation techniques, particularly studies of the ratios of isotopes of elements that are components of the ore bodies, hold much promise for understanding this complex pattern.' To this end, extensive use is now made of the isotopy of oxygen, sulphur, carbon, hydrogen, strontium, lead, neodymium and other elements. The SIMS technique provides a way of extending significantly the range of elements under investigation and improving the quality of prospecting,' by providing the unique capability of in situ isotopic measurements with lateral resolutions of <1 pm and minimal sample consumption. The method is of particular efficiency for constructing genetic geochemical models that serve as a theoretical basis for development of new prospecting criteria. Samples of ores and rocks from deposits and ore manifestations in the Ukraine (the Middle Near-Dnieper region, the Carpathians, the Donets Basin) were selected for investigation. These samples represent various genetic...

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Using photoinjection, C–U and SIMS techniques a comparative study of the creation process of electrically active centers, together with the accompanying variations of impurity structural characteristics of the oxide caused by field treatment of MOS structures, is carried out. It is shown that in structures with the negative charge distributed in the oxide the field treatment results in the creation of interfacial defects and in partial annealing of negatively charged traps. Hydrogen movement from the oxide surface towards the SiSiO2 interface and the appearance of SiOH complexes is observed. A generalized model of Poole‐Frenkel emission of Protons is developed.

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The influence of doping with TbF3 and subsequent annealing on the properties of vacuum thermally deposited SiOx films is investigated. It is shown that: (i) in spite of the conservation of the amorphous structure and the rather weak dependence of x and the optical characteristics on these factors they influence strongly the secondary ion mass spectra, the conductivity, and other characteristics, which are sensitive to the SiOx matrix microstructure, (ii) there are the initial stages of the phase separation in the films which are suppressed by the doping and promoted by the annealing. A modified random‐bonding model taking into account local x‐fluctuations is considered. This model allows to explain the impurity influence on the Si–O network. The role of the microstructural rearrangements in the susceptibility to the electroluminescence is discussed.