P. S. Zavyalov

Bio: P. S. Zavyalov is an academic researcher from Russian Academy of Sciences. The author has contributed to research in topics: Digital image processing & Mixing (physics). The author has an hindex of 3, co-authored 13 publications receiving 19 citations.

A structured-light method for the measurement of deformations in fuel assemblies in the cooling ponds of nuclear power plants

Abstract: Increasing the functional reliability, the lifetime, and the burn-up height are significant tasks for improving nuclear fuel. To solve these problems, it is necessary to ensure a high level of geometric stability for fuel assemblies during their operation in nuclear-power plants when mechanical deformations such as bending and twisting of the fuel assemblies are caused by various factors. In order to obtain objective information on the postreactor condition of fuel assemblies, analyze the information, and make recommendations for updating their structure, it is necessary to measure their geometric parameters in the cooling pond of a nuclear-power plant where the fuel assemblies are placed after they have operated in the reactor. Considering this problem, the authors developed and studied an optical structured-light method. This paper presents the theoretical calculations of the method and the experimental bench, describes the research, presents the results, and gives recommendations for the application of the method.

Development of Telecentric Objectives for Dimensional Inspection Systems

Abstract: Features of designing objectives telecentric in the object space are discussed. The optical layout of three telecentric objectives developed for dimensional inspection systems using the shadow projection method is presented. A method for monitoring the quality of manufacture of such objectives having small distortion (less than 0.02 %) and small non-telecentricity (less than 0.01°) is described. Comparison of experimentally obtained optical characteristics of two objectives manufactured by us and one objective manufactured by the Thorlabs company (U.S.) is carried out.

Diffractive focusing fan-out element for the parallel DNA sequencer

Abstract: Various issues of creation of diffractive optical elements transforming one laser beam with small divergence to a matrix of converging beams with a diffraction size of focused spots in the plane of object illumination and their application for problems of DNA sequencing and microscopy are considered. The parameters of diffractive elements are calculated and optimized in the approximation of the Fresnel–Kirchhoff diffraction theory. Diffractive elements are fabricated by the method of direct laser writing on a photoresist by using a circular laser writing system. Experimental characteristics of a diffractive element creating a matrix consisting of 33 × 33 beams, which are focused in one plane at a distance of 210 mm, are presented. The degree of nonuniformity of beam intensities determined by the ratio of beam intensities in the central region to intensities of peripheral beams is 1/2.5, which is potentially sufficient to be used in DNA sequencing problems. The maximum distortions of spot positions in the entire focusing field is <0.15%.

A dedicated optical system for the quality inspection of cylindrical surfaces

Abstract: Calculations of a dedicated optical system for the quality inspection of cylindrical surfaces are presented. Peculiarities of imaging a cylindrical surface by means of specially enhanced inherent field curvature are considered. Results of using the system for the inspection of quality of fuel pellets are provided.

A Contactless Method for Testing Inner Walls of Pipelines

Abstract: A new Doppler-effect–based method for nondestructive testing of the condition of the inner walls of pipelines using a flowing fluid is considered. An optical method has been used to reveal specific features in the structure of the fluid-medium flow in a circular-section pipeline. A new technique that makes use of laser radiation scattered on flowing-fluid particles has been proposed for determining the coordinates of a flawed zone on the inner pipeline wall. The technique makes it possible to determine the zone coordinates along the length and diameter of the pipeline.

Investigation of Computer-Generated Fresnel Holograms for Wavefront Sensors

Abstract: The possibility of using computer-generated Fresnel holograms to determine phase aberrations of a wavefront is studied. The results of computer simulation of the propagation of an elementary signal based on the Fresnel integral transform are presented. The principle of operation of a hologram for a wavefront sensor is discussed.