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In this work, the task was to investigate the properties of niobium oxide layers (geometric thickness, their optical constants n and k) in the design of a multilayer interference filter, in the manufacture of which a system for indirect control of the thickness of the deposited films is used. As an indirect control system, we used both quartz control and optical broadband control. The experiment was based on using a 6-position changer, which makes it possible to change the substrate on which the coating is deposited during the process of making a light filter by the electron beam evaporation. Thanks to this, we obtained substrates with a niobium oxide film, which corresponded to 1, 9, 17, 25 and 31 layers of an interference filter. Analysis of the obtained samples allows us to determine the geometric layer thickness, refractive index and absorption and to evaluate the effect of a change in the solid angle of the flow of the evaporated substance due to a change in the amount of substance in the crucible on the thickness of the sprayed film on the substrate, when we use indirect methods of thickness control. We used Ferrotec EV M-10 electron beam guns to evaporate the construction materials of the interference filter. For the evaporation of SiO2, a stock stream crucible was used; for the evaporation of Nb2O5, we ourselves made a special crucible in order to optimize the evaporation mode of this material. We managed to optimize the power of the electron beam and at the same time to obtain the desired form of the flow of the evaporated substance. Analysis of the obtained samples made it possible to answer the question of whether physicochemical changes in niobium oxide in the crucible occur when exposed to an electron beam for a sufficiently long time. In the course of the research, an X-ray phase analysis of the Nb2O5 film-forming material from various manufacturers was carried out.
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