Home – Home – Jornals – Avtometriya 2003 number 5

Severe requirements are imposed on the geometric parameters of the grid spacers in order to ensure a high reliability of fuel assemblies of nuclear reactors. They specify position of the beam of fuel elements in the transverse and longitudinal directions of the fuel assemblies. This is of extreme importance for preventing their corrosion and maintaining the required heat regime of functioning. A laser measuring machine (LMM) was developed and produced using the multipoint structured illumination method to ensure 100 % 3D inspection of the geometric parameters of grid spacers in Russian VVER-1000 nuclear reactors. A measurement method as well as hardware and software of the LMM are presented. Results of LMM testing in the industrial conditions are presented and discussed. Phase retrieval profilometer for in-process measurement of 3D microstructure surfaces

An optical method for measuring the profile of three-dimensional micro-surface structures is proposed. Spatial spectral information on a surface profile is obtained by measuring its diffraction intensity, from which the surface is reconstructed by using the phase retrieval. A surface with a staircase-like shape having four steps with each step 70 nm high was measured to demonstrate that the method works for arbitrary nonperiodic surface structures. The successfully reconstructed surface is shown. This diffraction method has a potential application in in-process measurements.

Triangulation optical methods for melt level measurement in a crucible during crystal growth are analyzed. Main attention is given to the active method using a laser triangulation sensor. Estimates of the metrological characteristics (systematic measurement errors and effective range) depending on the level of melt, its angular velocity, the distance from the measurement zone to the center of rotation, and the crucible coordinate are presented. The limit value of the melt rotation speed is also estimated. The requirements to the optical system providing the maximal measurement range and also to the algorithms of processing of the optical signal formed as the sensor beam is reflected from the nonstationary mirror surface are formulated. The features of melt level measurement using a passive binocular sensor are discussed.

The interferometric method of measuring diameters of circular reflecting cylinders is investigated. The interference field behavior under conditions of inaccurate positioning of the object measured is studied in the geometrical optics approach. It is shown that in recording a field in the remote zone the measurement error of object diameter, caused by its inaccurate positioning, is substantially diminished. To estimate the effect of light diffraction on the interference pattern, an equivalent model was constructed; according to this model, the field can be considered as a result of interference between a plane monochromatic wave and two point sources: a

Results of investigation directed to creating an optoelectronic system for inspecting the hole size in sieves used for diamond classification are presented. A technique of determining the sizes of holes by their images is described. Results of investigating the hole dimension measurement algorithm ensuring an error of 3 m and less are discussed. Characteristics of the automatic system for analytical sieve inspection are given.

A schematic diagram and the principle of operation of the biophotometer-spectrum analyzer, that is, an optical device of a new generation for medical diagnostics and treatment, are presented. Results of preliminary tests of the device in the clinical conditions are presented. They demonstrate the diagnostic opportunities of the device.

The way for design and analysis of a tunable Fabry-Perot filter (FPF) for monochromatic wave filtering is presented. The filter is filled with a liquid crystal (LC) to achieve controlled variation of the optic axis. The dependence of the spectral characteristics of the tunable FPF on the refractive index dispersion of the liquid crystal is explained in detail. The phase of reflection for the electromagnetic waves in the reflecting layers inside the filter was experimentally determined. A technique for determining the extinction in a transparent, scattering LC layer is described.

The possibility of applying adaptive-optics devices to ground-based solar astronomy and high-resolution spectroscopy is considered. Schemes of adaptive-optics systems with quadrant and correlation image shift detectors are proposed. Results of their testing in the Big Solar Vacuum Telescope  of the Baikal Astrophysical Observatory are presented. It is shown that an adaptive system with the quadrant detector will reduce the dispersion of image fragment jittering in the neighborhood of a crater by a factor of 16

New application areas of the fiber-optic interferometer in the Sagnac configuration are proposed and discussed. Because this system detects the absolute rotation in the plane of its sensor loop, the application is directly designed for detection of the rotational events. From the seismological point of view, such events are named seismic rotation waves. In most cases, the seismic rotation waves are extracted from recordings of differential seismic signals. Thus, all differences in responses of the seismometers cause disturbances that obscure these hidden components as it is for two antiparallel pendulum seismometers (TAPS) system. The presented fiber-optic rotational seismometer (FORS) is free from this disadvantage, and can be used for calibration of other rotational seismometers as well as for detection of seismic rotation waves. A design based on the well-known optical gyroscope configuration but with optimization for detection of only the pure rotation is presented. Its application for the TAPS system calibration is considered. The obtained results were the source of TAPS work improvement by applying the data smoothing by spline functions. Moreover, the first application of FORS has shown that probably the rotational parts exist in seismic events only for strong earthquakes.

The operation principles and software of optical and optical-television devices intended for detailed quantitative investigation of the processes of plastic flows and fracture of metals and alloys are considered. Data on their resolution, measurement accuracy, and efficiency are presented. Experimental potentialities of the proposed methods used in investigating the plastic deformation localization by specially designed schemes applying decorrelation of two speckle patterns of the deformed solid surface are evaluated. Data on the peculiarities of kinetics of the plastic shaping process, which were obtained by the described methods, are given as examples.

Quenching of fluorescence of pressure-sensitive paints with the use of pulsed ultraviolet lasers (excimer and nitrogen-based lasers) as a light-excitation source is considered. The lasers provide rather uniform illumination of pressure-sensitive paints at the following wavelengths: 248 (KrF), 307 (XeCl), 353 (XeF), and 337 nm (). The laser-pulse duration is 5

A mathematical model of tree rings in the form of an interference pattern is presented. The model allows retrospective reconstruction of continuous radial growth of a tree during the entire vegetation season. The radial dependence of the wood density is considered as a certain oscillation whose phase is a strictly increasing function of radius. The radial growth is defined as a monotonic function of time, inverse with respect to the phase. Algorithms for model analysis are based on the condition of dispersion causality. Experimental results are discussed.

The effect of generation of the second harmonic of the probing laser emission is used for express, local, nondestructive inspection of the quantitative and qualitative crystal characteristics of materials. Specification is presented and potentialities of a computer-aided laser system for output inspection of semiconductor crystal parameters are described. The system will determine during several minutes the crystallographic axes orientation with an error of  in local surface regions ( m in diameter and 0.1